Sample records for active transport system

  1. Active Transportation Surveillance - United States, 1999-2012.

    PubMed

    Whitfield, Geoffrey P; Paul, Prabasaj; Wendel, Arthur M

    2015-08-28

    Physical activity is a health-enhancing behavior, and most U.S. adults do not meet the 2008 Physical Activity Guidelines for Americans. Active transportation, such as by walking or bicycling, is one way that persons can be physically active. No comprehensive, multiyear assessments of active transportation surveillance in the United States have been conducted. 1999-2012. Five surveillance systems assess one or more components of active transportation. The American Community Survey and the National Household Travel Survey (NHTS) both assess the mode of transportation to work in the past week. From these systems, the proportion of respondents who reported walking or bicycling to work can be calculated. NHTS and the American Time Use Survey include 1-day assessments of trips or activities. With that information, the proportion of respondents who report any walking or bicycling for transportation can be calculated. The National Health and Nutrition Examination Survey and the National Health Interview Survey both assess recent (i.e., in the past week or past month) habitual physical activity behaviors, including those performed during active travel. From these systems, the proportion of respondents who report any recent habitual active transportation can be calculated. The prevalence of active transportation as the primary commute mode to work in the past week ranged from 2.6% to 3.4%. The 1-day assessment indicated that the prevalence of any active transportation ranged from 10.5% to 18.5%. The prevalence of any habitual active transportation ranged from 23.9% to 31.4%. No consistent trends in active transportation across time periods and surveillance systems were identified. Among systems, active transportation was usually more common among men, younger respondents, and minority racial/ethnic groups. Among education groups, the highest prevalence of active transportation was usually among the least or most educated groups, and active transportation tended to be more prevalent in densely populated, urban areas. Active transportation is assessed in a wide variety of ways in multiple surveillance systems. Different assessment techniques and construct definitions result in widely discrepant estimates of active transportation; however, some consistent patterns were detected across covariates. Although each type of assessment (i.e., transportation to work, single day, and habitual behavior) measures a different active transportation component, all can be used to monitor population trends in active transportation participation. An understanding of the strengths, limitations, and lack of comparability of active transportation assessment techniques is necessary to correctly evaluate findings from the various surveillance systems. When used appropriately, these systems can be used by public health and transportation professionals to monitor population participation in active transportation and plan and evaluate interventions that influence active transportation.

  2. Current status of the thiol redox model for the regulation of hexose transport by insulin.

    PubMed

    Czech, M P

    1976-12-01

    Data obtained over the last two years pertinent to the thiol redox model for the modulation of hexose transport activity by insulin is summarized. The model proposes that activation of hexose transport in fat cells involves sulfhydryl oxidation to the disulfide form in a key protein component of the fat cell surface membrane. Theoretically, the rapid activation of transport by insulin may involve either the conversion of inactive membrane carriers to the active form as originally proposed, or the conversion of a low Vmax transport system to a high Vmax form. The present experiments showed that the percent inhibition of insulin-activated transport rates by submaximal levels of cytochalasin B was decreased compared to its effects on basal transport. Treatment of fat cells with N-ethylmaleimide inhibited cytochalasin B action but not transport activity. When insulin or the oxidant vitamin K5 was added to cells 5 minutes before the N-ethylmaleimide, the elevated transport activity was also resistant to the sulfhydryl reagent, but cytochalasin B retained its potent inhibitory effect on transport. The data demonstrate that unique properties characterize basal versus insulin-activated transport activity with respect to the sensitivity of cytochalasin B action to sulfhydryl blockade in isolated fat cells. The data are consistent with the concept that activation of transport activity reflects the conversion of a reduced (sulfhydryl) system characterized by a low Vmax to an oxidized (disulfide), high Vmax transport system.

  3. Expression and functional characterisation of System L amino acid transporters in the human term placenta.

    PubMed

    Gaccioli, Francesca; Aye, Irving L M H; Roos, Sara; Lager, Susanne; Ramirez, Vanessa I; Kanai, Yoshikatsu; Powell, Theresa L; Jansson, Thomas

    2015-06-09

    System L transporters LAT1 (SLC7A5) and LAT2 (SLC7A8) mediate the uptake of large, neutral amino acids in the human placenta. Many System L substrates are essential amino acids, thus representing crucial nutrients for the growing fetus. Both LAT isoforms are expressed in the human placenta, but the relative contribution of LAT1 and LAT2 to placental System L transport and their subcellular localisation are not well established. Moreover, the influence of maternal body mass index (BMI) on placental System L amino acid transport is poorly understood. Therefore the aims of this study were to determine: i) the relative contribution of the LAT isoforms to System L transport activity in primary human trophoblast (PHT) cells isolated from term placenta; ii) the subcellular localisation of LAT transporters in human placenta; and iii) placental expression and activity of System L transporters in response to maternal overweight/obesity. System L mediated leucine uptake was measured in PHT cells after treatment with si-RNA targeting LAT1 and/or LAT2. The localisation of LAT isoforms was studied in isolated microvillous plasma membranes (MVM) and basal membranes (BM) by Western blot analysis. Results were confirmed by immunohistochemistry in sections of human term placenta. Expression and activity System L transporters was measured in isolated MVM from women with varying pre-pregnancy BMI. Both LAT1 and LAT2 isoforms contribute to System L transport activity in primary trophoblast cells from human term placenta. LAT1 and LAT2 transporters are highly expressed in the MVM of the syncytiotrophoblast layer at term. LAT2 is also localised in the basal membrane and in endothelial cells lining the fetal capillaries. Measurements in isolated MVM vesicles indicate that System L transporter expression and activity is not influenced by maternal BMI. LAT1 and LAT2 are present and functional in the syncytiotrophoblast MVM, whereas LAT2 is also expressed in the BM and in the fetal capillary endothelium. In contrast to placental System A and beta amino acid transporters, MVM System L activity is unaffected by maternal overweight/obesity.

  4. Down-Regulation of Placental Transport of Amino Acids Precedes the Development of Intrauterine Growth Restriction in Maternal Nutrient Restricted Baboons1

    PubMed Central

    Pantham, Priyadarshini; Rosario, Fredrick J.; Weintraub, Susan T.; Nathanielsz, Peter W.; Powell, Theresa L.; Li, Cun; Jansson, Thomas

    2016-01-01

    Intrauterine growth restriction (IUGR) is an important risk factor for perinatal complications and adult disease. IUGR is associated with down-regulation of placental amino acid transporter expression and activity at birth. It is unknown whether these changes are a cause or a consequence of human IUGR. We hypothesized that placental amino acid transport capacity is reduced prior to onset of reduced fetal growth in baboons with maternal nutrient restriction (MNR). Pregnant baboons were fed either a control (n = 8) or MNR diet (70% of control diet, n = 9) from Gestational Day 30. At Gestational Day 120 (0.65 of gestation), fetuses and placentas were collected. Microvillous (MVM) and basal (BM) plasma membrane vesicles were isolated. System A and system L transport activity was determined in MVM, and leucine transporter activity was assessed in BM using radiolabeled substrates. MVM amino acid transporter isoform expression (SNAT1, SNAT2, and SNAT4 and LAT1 and LAT2) was measured using Western blots. LAT1 and LAT2 expression were also determined in BM. Maternal and fetal plasma amino acids concentrations were determined using mass spectrometry. Fetal and placental weights were unaffected by MNR. MVM system A activity was decreased by 37% in MNR baboon placentas (P = 0.03); however MVM system A amino acid transporter protein expression was unchanged. MVM system L activity and BM leucine transporter activity were not altered by MNR. Fetal plasma concentrations of essential amino acids isoleucine and leucine were reduced, while citrulline increased (P < 0.05) in MNR fetuses compared to controls. In this primate model of IUGR, placental MVM system A amino acid transporter activity is decreased prior to the onset of reduction in the fetal growth trajectory. The reduction in plasma leucine and isoleucine in MNR fetuses may be caused by reduced activity of MVM system A, which is strongly coupled with system L essential amino acid uptake. Our findings indicate that reduced placental amino acid transport may be a cause rather than a consequence of IUGR due to inadequate maternal nutrition. PMID:27605346

  5. Down-Regulation of Placental Transport of Amino Acids Precedes the Development of Intrauterine Growth Restriction in Maternal Nutrient Restricted Baboons.

    PubMed

    Pantham, Priyadarshini; Rosario, Fredrick J; Weintraub, Susan T; Nathanielsz, Peter W; Powell, Theresa L; Li, Cun; Jansson, Thomas

    2016-11-01

    Intrauterine growth restriction (IUGR) is an important risk factor for perinatal complications and adult disease. IUGR is associated with down-regulation of placental amino acid transporter expression and activity at birth. It is unknown whether these changes are a cause or a consequence of human IUGR. We hypothesized that placental amino acid transport capacity is reduced prior to onset of reduced fetal growth in baboons with maternal nutrient restriction (MNR). Pregnant baboons were fed either a control (n = 8) or MNR diet (70% of control diet, n = 9) from Gestational Day 30. At Gestational Day 120 (0.65 of gestation), fetuses and placentas were collected. Microvillous (MVM) and basal (BM) plasma membrane vesicles were isolated. System A and system L transport activity was determined in MVM, and leucine transporter activity was assessed in BM using radiolabeled substrates. MVM amino acid transporter isoform expression (SNAT1, SNAT2, and SNAT4 and LAT1 and LAT2) was measured using Western blots. LAT1 and LAT2 expression were also determined in BM. Maternal and fetal plasma amino acids concentrations were determined using mass spectrometry. Fetal and placental weights were unaffected by MNR. MVM system A activity was decreased by 37% in MNR baboon placentas (P = 0.03); however MVM system A amino acid transporter protein expression was unchanged. MVM system L activity and BM leucine transporter activity were not altered by MNR. Fetal plasma concentrations of essential amino acids isoleucine and leucine were reduced, while citrulline increased (P < 0.05) in MNR fetuses compared to controls. In this primate model of IUGR, placental MVM system A amino acid transporter activity is decreased prior to the onset of reduction in the fetal growth trajectory. The reduction in plasma leucine and isoleucine in MNR fetuses may be caused by reduced activity of MVM system A, which is strongly coupled with system L essential amino acid uptake. Our findings indicate that reduced placental amino acid transport may be a cause rather than a consequence of IUGR due to inadequate maternal nutrition. © 2016 by the Society for the Study of Reproduction, Inc.

  6. 75 FR 49943 - New Agency Information Collection Activity Under OMB Review: Pipeline System Operator Security...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-16

    ... DEPARTMENT OF HOMELAND SECURITY Transportation Security Administration New Agency Information Collection Activity Under OMB Review: Pipeline System Operator Security Information AGENCY: Transportation... INFORMATION CONTACT: Joanna Johnson, Office of Information Technology, TSA-11, Transportation Security...

  7. ABCB1 and ABCC1-like transporters in immune system cells from sea urchins Echinometra lucunter and Echinus esculentus and oysters Crassostrea gasar and Crassostrea gigas.

    PubMed

    Marques-Santos, Luis Fernando; Hégaret, Hélène; Lima-Santos, Leonardo; Queiroga, Fernando Ramos; da Silva, Patricia Mirella

    2017-11-01

    ABC transporters activity and expression have been associated with the multixenobiotic resistance phenotype (MXR). The activity of these proteins leads to a reduction in the intracellular concentration of several xenobiotics, thus reducing their toxicity. However, little attention has been given to the expression of ABC transporters in marine invertebrates and few studies have investigated their role in immune system cells of sea urchins and shellfish bivalves. The aim of the present study was to investigate the activity of the ABC transporters ABCB1 and ABCC1 in immune system cells of sea urchins (coelomocytes) and oysters (hemocytes) from different climatic regions (Brazil and France). Sea urchins and oysters were collected at Paraíba coast; Brazil (Echinometra lucunter and Crassostrea gasar) and Rade of Brest; France (Echinus esculentus and Crassostrea gigas). Coelomocytes and hemocytes were stained with the ABC transporter substrate calcein-AM and dye accumulation analyzed under flow cytometry. Reversin 205 (ABCB1 transporter blocker) and MK571 (ABCC1 transporter blocker) were used as pharmacological tools to investigate ABC transporter activity. A different pattern of calcein accumulation was observed in coelomocytes: phagocytes > colorless spherulocytes > vibrate cells > red spherulocytes. The treatment with MK571 increased calcein fluorescence levels in coelomocytes from both species. However, reversin 205 treatment was not able to increase calcein fluorescence in E. esculentus coelomocytes. These data suggest that ABCC1-like transporter activity is present in both sea urchin species, but ABCB1-like transporter activity might only be present in E. lucunter coelomocytes. The activity of ABCC1-like transporter was observed in all cell types from both bivalve species. However, reversin 205 only increased calcein accumulation in hyalinocytes of the oyster C. gasar, suggesting the absence of ABCB1-like transporter activity in all other cell types, including hyalinocytes from the oyster C. gigas. Additionally, our results showed that C. gigas exhibited higher activity of ABCC1-like transporter in all hemocyte types than C. gasar. The present work is the first to characterize ABCB1 and ABCC1-like transporter activity in the immune system cells of sea urchins E. lucunter and E. esculentus and oysters. Our findings encourage the performing studies regarding ABC transporters activity/expression in immune system cells form marine invertebrates under stress conditions and the possible use of ABC transporters as biomarkers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Heating and Cooling System Design for a Modern Transportable Container

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Berger, Jason E.

    Sandia National Laboratories (SNL) has been tasked with the design of a modern transportable container (MTC) for use in high reliability transportation environments. The container is required to transport cargo capable of generating its own heat and operate under the United States’ climatic extremes. In response to these requirements, active heating and cooling is necessary to maintain a controlled environment inside the container. The following thesis project documents the design of an active heating, active cooling, and combined active heating and cooling system (now referred to as active heating and cooling systems) through computational thermal analyses, scoping of commercial systemmore » options, and mechanical integration with the container’s structure.« less

  9. Possible site-specific reagent for the general amino acid transport system of Saccharomyces cerevisiae.

    PubMed

    Larimore, F S; Roon, R J

    1978-02-07

    The general amino acid transport system of Saccharomyces cerevisiae functions in the uptake of neutral, basic, and acidic amino acids. The amino acid analogue N-delta-chloroacetyl-L-ornithine (NCAO) has been tested as potential site specific reagent for this system. L-Tryptophan, which is transported exclusively by the general transport system, was used as a substrate. In the presence of glucose as an energy source, NCAO inhibited tryptophan transport competitively (Ki = 80 micrometer) during short time intervals (1-2 min), but adding 100 micrometer NCAO to a yeast cell suspension resulted in a time-dependent activation of tryptophan transport during the first 15 min of treatment. Following the activation a time-dependent decay of tryptophan transport activity occurred. Approximately 80% inactivation of the system was observed after 90 min. When a yeast cell suspension was treated with NCAO in the absence of an energy source, an 80% inactivation of tryptophan transport occurred in 90 min. The inactivation was noncompetitive (Ki congruent to 60 micrometer) and could not be reversed by the removal of the NCAO. Addition of a five-fold excess of L-lysine during NCAO treatment or prevented inactivation of tryptophan transport. Under parallel conditions of incubation, other closely related transport systems were not inhibited by NCAO.

  10. Identification of two proline transport systems in Staphylococcus aureus and their possible roles in osmoregulation.

    PubMed

    Bae, J H; Miller, K J

    1992-02-01

    The food-borne pathogen Staphylococcus aureus is distinguished from other food-borne pathogens by its ability to grow at water activity values below 0.90. Previous studies have indicated that proline accumulation mediated by transport represents a primary osmoregulatory strategy utilized by this bacterium (C. B. Anderson and L. D. Witter, Appl. Environ, Microbiol. 43:1501-1503, 1982; I. Koujima, H. Hayashi, K. Tomochika, A. Okabe, and Y. Kanemasa, Appl. Environ. Microbiol. 35:467-470, 1978; K. J. Miller, S. C. Zelt, and J.-H. Bae, Curr. Microbiol. 23:131-137, 1991). In this study, we demonstrate the presence of two proline transport systems within whole cells of S. aureus, a high-affinity transport system (Km, 7 microM) and a low-affinity transport system (Km, 420 microM). Our results indicate that the low-affinity proline transport system is osmotically activated and is the primary system responsible for the accumulation of proline by this pathogen during growth at low water activity.

  11. Achieving global perfect homeostasis through transporter regulation

    PubMed Central

    Springer, Michael

    2017-01-01

    Nutrient homeostasis—the maintenance of relatively constant internal nutrient concentrations in fluctuating external environments—is essential to the survival of most organisms. Transcriptional regulation of plasma membrane transporters by internal nutrient concentrations is typically assumed to be the main mechanism by which homeostasis is achieved. While this mechanism is homeostatic we show that it does not achieve global perfect homeostasis—a condition where internal nutrient concentrations are completely independent of external nutrient concentrations for all external nutrient concentrations. We show that the criterion for global perfect homeostasis is that transporter levels must be inversely proportional to net nutrient flux into the cell and that downregulation of active transporters (activity-dependent regulation) is a simple and biologically plausible mechanism that meets this criterion. Activity-dependent transporter regulation creates a trade-off between robustness and efficiency, i.e., the system's ability to withstand perturbation in external nutrients and the transporter production rate needed to maintain homeostasis. Additionally, we show that a system that utilizes both activity-dependent transporter downregulation and regulation of transporter synthesis by internal nutrient levels can create a system that mitigates the shortcomings of each of the individual mechanisms. This analysis highlights the utility of activity-dependent regulation in achieving homeostasis and calls for a re-examination of the mechanisms of regulation of other homeostatic systems. PMID:28414718

  12. Trimodal Control of Ion-Transport Activity on Cyclo-oligo-(1→6)-β-D-glucosamine-Based Artificial Ion-Transport Systems.

    PubMed

    Roy, Arundhati; Saha, Tanmoy; Gening, Marina L; Titov, Denis V; Gerbst, Alexey G; Tsvetkov, Yury E; Nifantiev, Nikolay E; Talukdar, Pinaki

    2015-11-23

    Cyclo-oligo-(1→6)-β-D-glucosamines functionalized with hydrophobic tails are reported as a new class of transmembrane ion-transport system. These macrocycles with hydrophilic cavities were introduced as an alternative to cyclodextrins, which are supramolecular systems with hydrophobic cavities. The transport activities of these glycoconjugates were manipulated by altering the oligomericity of the macrocycles, as well as the length and number of attached tails. Hydrophobic tails of 3 different sizes were synthesized and coupled with each glucosamine scaffold through the amide linkage to obtain 18 derivatives. The ion-transport activity increased from di- to tetrameric glucosamine macrocycles, but decreased further when flexible pentameric glucosamine was introduced. The ion-transport activity also increased with increasing length of attached linkers. For a fixed length of linkers, the transport activity decreased when the number of such tails was reduced. All glycoconjugates displayed a uniform anion-selectivity sequence: Cl(-) >Br(-) >I(-) . From theoretical studies, hydrogen bonding between the macrocycle backbone and the anion bridged through water molecules was observed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Effects of prior exercise on the action of insulin-like growth factor I in skeletal muscle

    NASA Technical Reports Server (NTRS)

    Henriksen, E. J.; Louters, L. L.; Stump, C. S.; Tipton, C. M.

    1992-01-01

    Prior exercise increases insulin sensitivity for glucose and system A neutral amino acid transport activities in skeletal muscle. Insulin-like growth factor I (IGF-I) also activates these transport processes in resting muscle. It is not known, however, whether prior exercise increases IGF-I action in muscle. Therefore we determined the effect of a single exhausting bout of swim exercise on IGF-I-stimulated glucose transport activity [assessed by 2-deoxy-D-glucose (2-DG) uptake] and system A activity [assessed by alpha-(methylamino)isobutyric acid (MeAIB) uptake] in the isolated rat epitrochlearis muscle. When measured 3.5 h after exercise, the responses to a submaximal concentration (0.2 nM), but not a maximal concentration (13.3 nM), of insulin for activation of 2-DG uptake and MeAIB uptake were enhanced. In contrast, prior exercise increased markedly both the submaximal (5 nM) and maximal (20 nM) responses to IGF-I for activation of 2-DG uptake, whereas only the submaximal response to IGF-I (3 nM) for MeAIB uptake was enhanced after exercise. We conclude that 1) prior exercise significantly enhances the response to a submaximal concentration of IGF-I for activation of the glucose transport and system A neutral amino acid transport systems in skeletal muscle and 2) the enhanced maximal response for IGF-I action after exercise is restricted to the signaling pathway for activation of the glucose transport system.

  14. Framework for the Intelligent Transportation System (ITS) Evaluation : ITS Integration Activities

    DOT National Transportation Integrated Search

    2006-08-01

    Intelligent Transportation Systems (ITS) represent a significant opportunity to improve the efficiency and safety of the surface transportation system. ITS includes technologies to support information processing, communications, surveillance and cont...

  15. 2009 Iowa railroad system plan.

    DOT National Transportation Integrated Search

    2009-01-01

    The 2009 Iowa Railroad System Plan is intended to guide the Iowa Department of Transportation (DOT) in its activities of promoting access to rail transportation, helping to improve the freight railroad transportation system, expanding passenger rail ...

  16. Binding proteins enhance specific uptake rate by increasing the substrate-transporter encounter rate.

    PubMed

    Bosdriesz, Evert; Magnúsdóttir, Stefanía; Bruggeman, Frank J; Teusink, Bas; Molenaar, Douwe

    2015-06-01

    Microorganisms rely on binding-protein assisted, active transport systems to scavenge for scarce nutrients. Several advantages of using binding proteins in such uptake systems have been proposed. However, a systematic, rigorous and quantitative analysis of the function of binding proteins is lacking. By combining knowledge of selection pressure and physiochemical constraints, we derive kinetic, thermodynamic, and stoichiometric properties of binding-protein dependent transport systems that enable a maximal import activity per amount of transporter. Under the hypothesis that this maximal specific activity of the transport complex is the selection objective, binding protein concentrations should exceed the concentration of both the scarce nutrient and the transporter. This increases the encounter rate of transporter with loaded binding protein at low substrate concentrations, thereby enhancing the affinity and specific uptake rate. These predictions are experimentally testable, and a number of observations confirm them. © 2015 FEBS.

  17. 2009 Iowa railroad system plan : cover.

    DOT National Transportation Integrated Search

    2009-01-01

    The 2009 Iowa Railroad System Plan is intended to guide the Iowa Department of Transportation (DOT) in its activities of promoting access to rail transportation, helping to improve the freight railroad transportation system, expanding passenger rail ...

  18. 2009 Iowa railroad system plan : part I.

    DOT National Transportation Integrated Search

    2009-01-01

    The 2009 Iowa Railroad System Plan is intended to guide the Iowa Department of Transportation (DOT) in its activities of promoting access to rail transportation, helping to improve the freight railroad transportation system, expanding passenger rail ...

  19. 2009 Iowa railroad system plan : part III.

    DOT National Transportation Integrated Search

    2009-01-01

    The 2009 Iowa Railroad System Plan is intended to guide the Iowa Department of Transportation (DOT) in its activities of promoting access to rail transportation, helping to improve the freight railroad transportation system, expanding passenger rail ...

  20. 2009 Iowa railroad system plan : part II.

    DOT National Transportation Integrated Search

    2009-01-01

    The 2009 Iowa Railroad System Plan is intended to guide the Iowa Department of Transportation (DOT) in its activities of promoting access to rail transportation, helping to improve the freight railroad transportation system, expanding passenger rail ...

  1. 49 CFR 234.106 - Partial activation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING SIGNAL SYSTEMS, STATE ACTION PLANS, AND EMERGENCY NOTIFICATION SYSTEMS Response to Credible Reports of Warning System Malfunction at Highway-Rail...

  2. 49 CFR 234.107 - False activation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING SIGNAL SYSTEMS, STATE ACTION PLANS, AND EMERGENCY NOTIFICATION SYSTEMS Response to Credible Reports of Warning System Malfunction at Highway-Rail...

  3. 49 CFR 234.105 - Activation failure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING SIGNAL SYSTEMS, STATE ACTION PLANS, AND EMERGENCY NOTIFICATION SYSTEMS Response to Credible Reports of Warning System Malfunction at Highway-Rail...

  4. 49 CFR 234.107 - False activation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING SIGNAL SYSTEMS, STATE ACTION PLANS, AND EMERGENCY NOTIFICATION SYSTEMS Response to Credible Reports of Warning System Malfunction at Highway-Rail...

  5. 49 CFR 234.107 - False activation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING SIGNAL SYSTEMS, STATE ACTION PLANS, AND EMERGENCY NOTIFICATION SYSTEMS Response to Credible Reports of Warning System Malfunction at Highway-Rail...

  6. 49 CFR 234.106 - Partial activation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING SIGNAL SYSTEMS, STATE ACTION PLANS, AND EMERGENCY NOTIFICATION SYSTEMS Response to Credible Reports of Warning System Malfunction at Highway-Rail...

  7. 49 CFR 234.105 - Activation failure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING SIGNAL SYSTEMS, STATE ACTION PLANS, AND EMERGENCY NOTIFICATION SYSTEMS Response to Credible Reports of Warning System Malfunction at Highway-Rail...

  8. 49 CFR 234.106 - Partial activation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING SIGNAL SYSTEMS, STATE ACTION PLANS, AND EMERGENCY NOTIFICATION SYSTEMS Response to Credible Reports of Warning System Malfunction at Highway-Rail...

  9. 49 CFR 234.105 - Activation failure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SAFETY, INCLUDING SIGNAL SYSTEMS, STATE ACTION PLANS, AND EMERGENCY NOTIFICATION SYSTEMS Response to Credible Reports of Warning System Malfunction at Highway-Rail...

  10. 2009 Iowa railroad system plan : introduction.

    DOT National Transportation Integrated Search

    2009-01-01

    The 2009 Iowa Railroad System Plan is intended to guide the Iowa Department of Transportation (DOT) in its activities of promoting access to rail transportation, helping to improve the freight railroad transportation system, expanding passenger rail ...

  11. Regulation of amino acid transport in Escherichia coli by transcription termination factor rho.

    PubMed

    Quay, S C; Oxender, D L

    1977-06-01

    Amino acid transport rates and amino acid binding proteins were examined in a strain containing the rho-120 mutation (formerly SuA), which has been shown to lower the rho-dependent, ribonucleic acid-activated adenosine triphosphatase activity to 9% of the rho activity in the isogenic wild-type strain. Tryptophan and proline transport, which occur by membrane-bound systems, were not altered. On the other hand, arginine, histidine, leucine, isoleucine, and valine transport were variably increased by a factor of 1.4 to 5.0. Kinetics of leucine transport showed that the LIV (leucine, isoleucine, and valine)-I (binding protein-associated) transport system is increased 8.5-fold, whereas the LIV-II (membrane-bound) system is increased 1.5-fold in the rho mutant under leucine-limited growth conditions. The leucine binding protein is increased fourfold under the same growth conditions. The difference in leucine transport in these strains was greatest during leucine-limited growth; growth on complex media repressed both strains to the same transport activity. We propose that rho-dependent transcriptional termination is important for leucine-specific repression of branched-chain amino acid transport, although rho-independent regulation, presumably by a corepressor-aporepressor-type mechanism, must also occur.

  12. Calcium transport in tonoplast and endoplasmic reticulum vesicles isolated from cultured carrot cells. [Daucus carota Danvers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bush, D.R.; Sze, H.

    1986-02-01

    Two active calcium (Ca/sup 2 +/) transport systems have been identified and partially characterized in membrane vesicles isolated from cultured carrot cells (Daucus carota Danvers). Both transport systems required MgATP for activity and were enhanced by 10 millimolar oxalate. Ca/sup 2 +/ transport in membrane vesicles derived from isolated vacuoles equilibrated at 1.10 grams per cubic centimeter and comigrated with Cl/sup -/-stimulated, NO/sub 3//sup -/-inhibited ATPase activity on sucrose density gradients. Ca/sup 2 +/ transport in this system was insensitive to vanadate, but was inhibited by nitrate, carbonyl cyanide-m-chlorophenylhydrazone (CCCP), N,N'-dicyclohexylcarbodiimide (DCCD), and 4,4-diisothiocyano-2,2'-stilbene disulfonic acid (DIDS). The K/sub m/more » for MgATP and Ca/sup 2 +/ were 0.1 mM and 21 micromolar, respectively. The predominant Ca/sup 2 +/ transport system detectable in microsomal membrane preparations equilibrated at a density of 1.13 grams per cubic centimeter and comigrated with the endoplasmic reticulum (ER) marker, antimycin A-insensitive NADH-dependent cytochrome c reductase. Ca/sup 2 +/ transport activity and the ER marker also shifted in parallel in ER shifting experiments. This transport system was inhibited by vanadate (I/sub 50/ = 12 micromolar) and was insensitive to nitrate, CCCP, DCCD, and DIDS. Transport exhibited cooperative MgATP dependent kinetics. Ca/sup 2 +/ dependent kinetics were complex with an apparent K/sub m/ ranging from 0.7 to 2 micromolar. We conclude that the vacuolar-derived system is a Ca/sup 2 +//H/sup +/ antiport located on the tonoplast and that the microsomal transport system is a Ca,Mg-ATPase enriched on the ER. These two Ca/sup 2 +/ transport systems are proposed to restore and maintain cytoplasmic Ca/sup 2 +/ homeostasis under changing cellular and environmental conditions.« less

  13. Engineering intracellular active transport systems as in vivo biomolecular tools.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bachand, George David; Carroll-Portillo, Amanda

    2006-11-01

    Active transport systems provide essential functions in terms of cell physiology and metastasis. These systems, however, are also co-opted by invading viruses, enabling directed transport of the virus to and from the cell's nucleus (i.e., the site of virus replication). Based on this concept, fundamentally new approaches for interrogating and manipulating the inner workings of living cells may be achievable by co-opting Nature's active transport systems as an in vivo biomolecular tool. The overall goal of this project was to investigate the ability to engineer kinesin-based transport systems for in vivo applications, specifically the collection of effector proteins (e.g., transcriptionalmore » regulators) within single cells. In the first part of this project, a chimeric fusion protein consisting of kinesin and a single chain variable fragment (scFv) of an antibody was successfully produced through a recombinant expression system. The kinesin-scFv retained both catalytic and antigenic functionality, enabling selective capture and transport of target antigens. The incorporation of a rabbit IgG-specific scFv into the kinesin established a generalized system for functionalizing kinesin with a wide range of target-selective antibodies raised in rabbits. The second objective was to develop methods of isolating the intact microtubule network from live cells as a platform for evaluating kinesin-based transport within the cytoskeletal architecture of a cell. Successful isolation of intact microtubule networks from two distinct cell types was demonstrated using glutaraldehyde and methanol fixation methods. This work provides a platform for inferring the ability of kinesin-scFv to function in vivo, and may also serve as a three-dimensional scaffold for evaluating and exploiting kinesin-based transport for nanotechnological applications. Overall, the technology developed in this project represents a first-step in engineering active transport system for in vivo applications. Further development could potentially enable selective capture of intracellular antigens, targeted delivery of therapeutic agents, or disruption of the transport systems and consequently the infection and pathogenesis cycle of biothreat agents.« less

  14. 49 CFR 234.105 - Activation failure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Activation failure. 234.105 Section 234.105 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY AND STATE ACTION PLANS Response to Reports...

  15. 49 CFR 234.107 - False activation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false False activation. 234.107 Section 234.107 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY AND STATE ACTION PLANS Response to Reports...

  16. 49 CFR 234.106 - Partial activation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Partial activation. 234.106 Section 234.106 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY AND STATE ACTION PLANS Response to Reports...

  17. 49 CFR 234.106 - Partial activation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Partial activation. 234.106 Section 234.106 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY AND STATE ACTION PLANS Response to Reports...

  18. 49 CFR 234.105 - Activation failure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Activation failure. 234.105 Section 234.105 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY AND STATE ACTION PLANS Response to Reports...

  19. 49 CFR 234.107 - False activation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false False activation. 234.107 Section 234.107 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY AND STATE ACTION PLANS Response to Reports...

  20. Paratransit and Transit Integration Areawide Demand Responsive Transportation System - Program Analysis

    DOT National Transportation Integrated Search

    1977-04-01

    The Urban Mass Transportation Administration carries out research and developmet on Areawide Demand Responsive Transportation (AWDRT) systems as part of the Bus and Paratransit Technoloy activities. AWDRT systems are basically the interation of flexi...

  1. 77 FR 71430 - New Agency Information Collection Activity Under OMB Review: Public Transportation Baseline...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-30

    ... DEPARTMENT OF HOMELAND SECURITY Transportation Security Administration New Agency Information Collection Activity Under OMB Review: Public Transportation Baseline Assessment for Security Enhancement... voluntary site visits with security and operating officials of public transportation systems. This program...

  2. Space Transportation System Payloads Data and Analysis

    NASA Technical Reports Server (NTRS)

    Peterson, J. D.; Craft, H. G., Jr.

    1975-01-01

    The background, current developments and future plans for the Space Transportation System Payloads Data and Analysis (SPDA) activities at Marshall Space Flight Center are reviewed. It is shown how the payload data bank and future planned activities will interface with the payloads community and Space Transportation System designers. The interfaces with the STS data base include NASA planning, international planning, payload design, shuttle design, user agencies planning and information, and OMB, Congress and others.

  3. The Science of Transportation Analysis and Simulation

    NASA Astrophysics Data System (ADS)

    Gleibe, John

    2010-03-01

    Transportation Science focuses on methods developed to model and analyze the interaction between human behavior and transportation systems. From the human behavioral, or demand, perspective, we are interested in how person and households organize their activities across space and time, with travel viewed as an enabling activity. We have a particular interest in how to model the range of responses to public policy and transportation system changes, which leads to the consideration of both short- and long-term decision-making, interpersonal dependencies, and non-transportation-related opportunities and constraints, including household budgets, land use systems and economic systems. This has led to the development of complex structural econometric modeling systems as well as agent-based simulations. From the transportation systems, or supply, perspective we are interested in the level of service provide by transportation facilities, be it auto, transit or multi-modal systems. This has led to the development of network models and equilibrium concepts as well as hybrid simulation systems based on concepts borrowed from physics, such as fluid flow models, and cellular automata-type models. In this presentation, we review a representative sample of these methods and their use in transportation planning and public policy analysis.

  4. Transport and health: a look at three Latin American cities.

    PubMed

    Becerra, Janeth Mosquera; Reis, Rodrigo S; Frank, Lawrence D; Ramirez-Marrero, Farah A; Welle, Benjamin; Arriaga Cordero, Eugenio; Mendez Paz, Fabian; Crespo, Carlos; Dujon, Veronica; Jacoby, Enrique; Dill, Jennifer; Weigand, Lynn; Padin, Carlos M

    2013-04-01

    Transport is associated with environmental problems, economic losses, health and social inequalities. A number of European and US cities have implemented initiatives to promote multimodal modes of transport. In Latin America changes are occurring in public transport systems and a number of projects aimed at stimulating non-motorized modes of transport (walking and cycling) have already been implemented. Based on articles from peer-reviewed academic journals, this paper examines experiences in Bogotá (Colombia), Curitiba (Brazil), and Santiago (Chile), and identifies how changes to the transport system contribute to encourage active transportation. Bus rapid transit, ciclovias, bike paths/lanes, and car use restriction are initiatives that contribute to promoting active transportation in these cities. Few studies have been carried out on the relationship between transport and physical activity. Car ownership continues to increase. The public health sector needs to be a stronger activist in the transport policy decision-making process to incorporate health issues into the transport agenda in Latin America.

  5. Development and testing of heat transport fluids for use in active solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Parker, J. C.

    1981-01-01

    Work on heat transport fluids for use with active solar heating and cooling systems is described. Program objectives and how they were accomplished including problems encountered during testing are discussed.

  6. Assay of Ca2+ transport by VDAC1 reconstituted into liposomes.

    PubMed

    Ben-Hail, Danya; Shoshan-Barmatz, Varda

    2014-02-01

    Ca(2+) permeability mediated by voltage-dependent anion-selective channel protein 1 (VDAC1) can be tested by reconstitution of purified VDAC1 into liposomes. Here, we describe a setup for this membranal system, which has been used to study the transport activity of various transporters, including VDAC1, and allows detection of the passage of molecules across the lipid bilayer. Despite the disadvantage of needing radiolabeled molecules, this system is highly desirable when the transport properties of noncharged molecules and/or active transporters are studied.

  7. Abundance of amino acid transporters involved in mTORC1 activation in skeletal muscle of neonatal pigs is developmentally regulated

    USDA-ARS?s Scientific Manuscript database

    Previously we demonstrated that the insulinand amino acid-induced activation of the mammalian target of rapamycin complex 1 (mTORC1) is developmentally regulated in neonatal pigs. Recent studies have indicated that members of the System A transporter (SNAT2), the System N transporter (SNAT3), the Sy...

  8. TNF-α stimulates System A amino acid transport in primary human trophoblast cells mediated by p38 MAPK signaling

    PubMed Central

    Aye, Irving L M H; Jansson, Thomas; Powell, Theresa L

    2015-01-01

    Maternal obesity and gestational diabetes mellitus (GDM) increase the risk of delivering infants that are large for gestational age with greater adiposity, who are prone to the development of metabolic disease in childhood and beyond. These maternal conditions are also associated with increased levels of the proinflammatory cytokine TNF-α in maternal tissues and the placenta. Recent evidence suggests that changes in placental amino acid transport contribute to altered fetal growth. TNF-α was previously shown to stimulate System A amino acid transport in primary human trophoblasts (PHTs), however the molecular mechanisms remain unknown. In this study, we tested the hypothesis that TNF-α regulates amino acid uptake in cultured PHTs by a mitogen-activated protein kinase (MAPK)-dependent mechanism. Treatment of PHTs with TNF-α significantly increased System A amino acid transport, as well as Erk and p38 MAPK signaling. Pharmacological antagonism of p38, but not Erk MAPK activity, inhibited TNF-α stimulated System A activity. Silencing of p38 MAPK using siRNA transfections prevented TNF-α stimulated System A transport in PHTs. TNF-α significantly increased the protein expression of System A transporters SNAT1 and SNAT2, but did not affect their mRNA expression. The effects of TNF-α on SNAT1 and SNAT2 protein expression were reversed by p38 MAPK siRNA silencing. In conclusion, TNF-α regulates System A activity through increased SNAT1 and SNAT2 transporter protein expression in PHTs. These findings suggest that p38 MAPK may represent a critical mechanistic link between elevated proinflammatory cytokines and increased placental amino acid transport in obese and GDM pregnancies associated with fetal overgrowth. PMID:26508738

  9. Contextual barriers to lifestyle physical activity interventions in Hong Kong.

    PubMed

    Eves, Frank F; Masters, Rich S W; McManus, Alison; Leung, Moon; Wong, Peggy; White, Mike J

    2008-05-01

    Increased lifestyle physical activity, for instance, use of active transport, is a current public health target. Active transport interventions that target stair climbing are consistently successful in English-speaking populations yet unsuccessful in Hong Kong. We report two further studies on active transport in the Hong Kong Chinese. Pedestrians on a mass transit escalator system (study 1) and in an air-conditioned shopping mall (study 2) were encouraged to take the stairs for their cardiovascular health by point-of-choice prompts. Observers coded sex, age, and walking on the mass transit system, with the additional variables of presence of children and bags coded in the shopping mall. In the first study, a 1-wk baseline was followed by 4 wk of intervention (N = 76,710) whereas in the second study (shopping mall) a 2-wk baseline was followed by a 2-wk intervention period (N = 18,257). A small but significant increase in stair climbing (+0.29%) on the mass transit system contrasted with no significant changes in the shopping mall (+0.09%). The active transport of walking on the mass transit system was reduced at higher rates of humidity and temperature, with steeper slopes for the effects of climate variables in men than in women. These studies confirm that lifestyle physical activity interventions do not have universal application. The context in which the behavior occurs (e.g., climate) may act as a barrier to active transport.

  10. The contribution of SNAT1 to system A amino acid transporter activity in human placental trophoblast

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Desforges, M., E-mail: michelle.desforges@manchester.ac.uk; Greenwood, S.L.; Glazier, J.D.

    2010-07-16

    Research highlights: {yields} mRNA levels for SNAT1 are higher than other system A subtype mRNAs in primary human cytotrophoblast. {yields} SNAT1 knockdown in cytotrophoblast cells significantly reduces system A activity. {yields} SNAT1 is a key contributor to system A-mediated amino acid transport in human placenta. -- Abstract: System A-mediated amino acid transport across the placenta is important for the supply of neutral amino acids needed for fetal growth. All three system A subtypes (SNAT1, 2, and 4) are expressed in human placental trophoblast suggesting there is an important biological role for each. Placental system A activity increases as pregnancy progresses,more » coinciding with increased fetal nutrient demands. We have previously shown SNAT4-mediated system A activity is higher in first trimester than at term, suggesting that SNAT1 and/or SNAT2 are responsible for the increased system A activity later in gestation. However, the relative contribution of each subtype to transporter activity in trophoblast at term has yet to be evaluated. The purpose of this study was to identify the predominant subtype of system A in cytotrophoblast cells isolated from term placenta, maintained in culture for 66 h, by: (1) measuring mRNA expression of the three subtypes and determining the Michaelis-Menten constants for uptake of the system A-specific substrate, {sup 14}C-MeAIB, (2) investigating the contribution of SNAT1 to total system A activity using siRNA. Results: mRNA expression was highest for the SNAT1 subtype of system A. Kinetic analysis of {sup 14}C-MeAIB uptake revealed two distinct transport systems; system 1: K{sub m} = 0.38 {+-} 0.12 mM, V{sub max} = 27.8 {+-} 9.0 pmol/mg protein/20 min, which resembles that reported for SNAT1 and SNAT2 in other cell types, and system 2: K{sub m} = 45.4 {+-} 25.0 mM, V{sub max} = 1190 {+-} 291 pmol/mg protein/20 min, which potentially represents SNAT4. Successful knockdown of SNAT1 mRNA using target-specific siRNA significantly reduced system A activity (median 75% knockdown, n = 7). Conclusion: These data enhance our limited understanding of the relative importance of the system A subtypes for amino acid transport in human placental trophoblast by demonstrating that SNAT1 is a key contributor to system A activity at term.« less

  11. Intracellular acidification reduces l-arginine transport via system y+L but not via system y+/CATs and nitric oxide synthase activity in human umbilical vein endothelial cells.

    PubMed

    Ramírez, Marco A; Morales, Jorge; Cornejo, Marcelo; Blanco, Elias H; Mancilla-Sierpe, Edgardo; Toledo, Fernando; Beltrán, Ana R; Sobrevia, Luis

    2018-04-01

    l-Arginine is taken up via the cationic amino acid transporters (system y + /CATs) and system y + L in human umbilical vein endothelial cells (HUVECs). l-Arginine is the substrate for endothelial NO synthase (eNOS) which is activated by intracellular alkalization, but nothing is known regarding modulation of system y + /CATs and system y + L activity, and eNOS activity by the pHi in HUVECs. We studied whether an acidic pHi modulates l-arginine transport and eNOS activity in HUVECs. Cells loaded with a pH-sensitive probe were subjected to 0.1-20 mmol/L NH 4 Cl pulse assay to generate pHi 7.13-6.55. Before pHi started to recover, l-arginine transport (0-20 or 0-1000 μmol/L, 10 s, 37 °C) in the absence or presence of 200 μmol/L N-ethylmaleimide (NEM) (system y + /CATs inhibitor) or 2 mmol/L l-leucine (systemy + L substrate) was measured. Protein abundance for eNOS and serine 1177 or threonine 495 phosphorylated eNOS was determined. The results show that intracellular acidification reduced system y + L but not system y + /CATs mediated l-arginine maximal transport capacity due to reduced maximal velocity. Acidic pHi reduced NO synthesis and eNOS serine 1177 phosphorylation. Thus, system y + L activity is downregulated by an acidic pHi, a phenomenon that may result in reduced NO synthesis in HUVECs. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Rapid Pneumatic Transport of Radioactive Samples - RaPToRS

    NASA Astrophysics Data System (ADS)

    Padalino, S.; Barrios, M.; Sangster, C.

    2005-10-01

    Some ICF neutron activation diagnostics require quick retrieval of the activated sample. Minimizing retrieval times is particularly important when the half-life of the activated material is on the order of the transport time or the degree of radioactivity is close to the background counting level. These restrictions exist in current experiments performed at the Laboratory for Laser Energetics, thus motivating the development of the RaPToRS system. The system has been designed to minimize transportation time while requiring no human intervention during transport or counting. These factors will be important if the system is to be used at the NIF where radiological hazards will be present during post activation. The sample carrier is pneumatically transported via a 4 inch ID PVC pipe to a remote location in excess of 100 meters from the activation site at a speed of approximately 7 m/s. It arrives at an end station where it is dismounted robotically from the carrier and removed from its hermetic package. The sample is then placed by the robot in a counting station. This system is currently being developed to measure back-to-back gamma rays produced by positron annihilation which were emitted by activated graphite. Funded in part by the U.S. DOE under sub contract with LLE at the University of Rochester.

  13. Us in a Bus: A Transportation Manual for Head Start Programs.

    ERIC Educational Resources Information Center

    Education Development Center, Inc., Newton, MA.

    The purpose of this manual is to provide Head Start directors, transportation supervisors, and trainers with information and activities that will help develop, enhance, and maintain a safe and efficient transportation system for their programs. Contents are organized into three categories: safety procedures, planning a transportation system, and…

  14. Development, deployment, and assessment of activity-based transportation courses.

    DOT National Transportation Integrated Search

    2012-12-01

    This project developed four new activitybased transportation courses including Traffic Signal Systems Operations and Design, Understanding and Communicating Transportation Data, Introduction to Freight Transportation, and Rura...

  15. Osmoregulated ABC-transport system of Lactococcus lactis senses water stress via changes in the physical state of the membrane.

    PubMed

    van der Heide, T; Poolman, B

    2000-06-20

    An osmoregulated ABC transporter (OpuA) with novel structural features has been identified that responds to water stress. This glycine betaine transport system consists of an ATP-binding/hydrolyzing subunit (OpuAA) and a protein (OpuABC) that contains both the translocator and the substrate-binding domain. The components of OpuA have been overexpressed, purified, and functionally incorporated into liposomes with an ATP-regenerating system in the vesicle lumen. A transmembrane osmotic gradient (outside hyperosmotic relative to the inside) of both ionic and nonionic compounds was able to osmotically activate OpuA in the proteoliposomal system. Hypoosmotic medium conditions inhibited the basal activity of the system. The data show that OpuAA and OpuABC are sufficient for osmoregulated transport, indicating that OpuA can act both as osmosensor and osmoregulator. Strikingly, OpuA could also be activated by low concentrations of cationic and anionic amphipaths, which interact with the membrane. This result indicates that activation by a transmembrane osmotic gradient is mediated by changes in membrane properties/protein-lipid interactions.

  16. Osmoregulated ABC-transport system of Lactococcus lactis senses water stress via changes in the physical state of the membrane

    PubMed Central

    van der Heide, Tiemen; Poolman, Bert

    2000-01-01

    An osmoregulated ABC transporter (OpuA) with novel structural features has been identified that responds to water stress. This glycine betaine transport system consists of an ATP-binding/hydrolyzing subunit (OpuAA) and a protein (OpuABC) that contains both the translocator and the substrate-binding domain. The components of OpuA have been overexpressed, purified, and functionally incorporated into liposomes with an ATP-regenerating system in the vesicle lumen. A transmembrane osmotic gradient (outside hyperosmotic relative to the inside) of both ionic and nonionic compounds was able to osmotically activate OpuA in the proteoliposomal system. Hypoosmotic medium conditions inhibited the basal activity of the system. The data show that OpuAA and OpuABC are sufficient for osmoregulated transport, indicating that OpuA can act both as osmosensor and osmoregulator. Strikingly, OpuA could also be activated by low concentrations of cationic and anionic amphipaths, which interact with the membrane. This result indicates that activation by a transmembrane osmotic gradient is mediated by changes in membrane properties/protein–lipid interactions. PMID:10860977

  17. 48 CFR 47.105 - Transportation assistance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Transportation assistance... MANAGEMENT TRANSPORTATION General 47.105 Transportation assistance. (a) Civilian Government activities that do not have transportation officers, or otherwise need assistance on transportation matters, shall...

  18. 48 CFR 47.105 - Transportation assistance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Transportation assistance... MANAGEMENT TRANSPORTATION General 47.105 Transportation assistance. (a) Civilian Government activities that do not have transportation officers, or otherwise need assistance on transportation matters, shall...

  19. 48 CFR 47.105 - Transportation assistance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Transportation assistance... MANAGEMENT TRANSPORTATION General 47.105 Transportation assistance. (a) Civilian Government activities that do not have transportation officers, or otherwise need assistance on transportation matters, shall...

  20. 48 CFR 47.105 - Transportation assistance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Transportation assistance... MANAGEMENT TRANSPORTATION General 47.105 Transportation assistance. (a) Civilian Government activities that do not have transportation officers, or otherwise need assistance on transportation matters, shall...

  1. 48 CFR 47.105 - Transportation assistance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Transportation assistance... MANAGEMENT TRANSPORTATION General 47.105 Transportation assistance. (a) Civilian Government activities that do not have transportation officers, or otherwise need assistance on transportation matters, shall...

  2. Memoryless self-reinforcing directionality in endosomal active transport within living cells

    NASA Astrophysics Data System (ADS)

    Chen, Kejia; Wang, Bo; Granick, Steve

    2015-06-01

    In contrast to Brownian transport, the active motility of microbes, cells, animals and even humans often follows another random process known as truncated Lévy walk. These stochastic motions are characterized by clustered small steps and intermittent longer jumps that often extend towards the size of the entire system. As there are repeated suggestions, although disagreement, that Lévy walks have functional advantages over Brownian motion in random searching and transport kinetics, their intentional engineering into active materials could be useful. Here, we show experimentally in the classic active matter system of intracellular trafficking that Brownian-like steps self-organize into truncated Lévy walks through an apparent time-independent positive feedback such that directional persistence increases with the distance travelled persistently. A molecular model that allows the maximum output of the active propelling forces to fluctuate slowly fits the experiments quantitatively. Our findings offer design principles for programming efficient transport in active materials.

  3. NanoShuttles: Harnessing Motor Proteins to Transport Cargo in Synthetic Environments

    NASA Astrophysics Data System (ADS)

    Vogel, V.; Hess, H.

    Motors have become a crucial commodity in our daily lives, from transportation to driving conveyor belts that enable the sequential assembly of cars and other industrial machines. For the sequential assembly of building blocks at the nanoscale that would not assemble spontaneously into larger functional systems, however, active transport systems are not yet available. In contrast, cells have evolved sophisticated molecular machinery that drives movement and active transport. Driven by the conversion of chemical into mechanical energy, namely through hydrolysis of the biological fuel ATP, molecular motors enable cells to operate far away from equilibrium by transporting organelles and molecules to designated locations within the cell, often against concentration gradients. Inspired by the biological concept of active transport, major efforts are underway to learn how to build nanoscale transport systems that are driven by molecular motors. Emerging engineering principles are discussed of how to build tracks and junctions to guide such nanoshuttles, how to load them with cargo and control their speed, how to use active transport to assemble mesoscopic structures that would otherwise not assemble spontaneously and what polymeric materials to choose to integrate motors into MEMS and other biohybrid devices. Finally, two applications that exploit the physical properties of microtubules are discussed, surface imaging by a swarm of microtubules and a self-assembled picoNewton force meter to probe receptor-ligand interactions.

  4. Introduction to Solid Supported Membrane Based Electrophysiology

    PubMed Central

    Bazzone, Andre; Costa, Wagner Steuer; Braner, Markus; Călinescu, Octavian; Hatahet, Lina; Fendler, Klaus

    2013-01-01

    The electrophysiological method we present is based on a solid supported membrane (SSM) composed of an octadecanethiol layer chemisorbed on a gold coated sensor chip and a phosphatidylcholine monolayer on top. This assembly is mounted into a cuvette system containing the reference electrode, a chlorinated silver wire. After adsorption of membrane fragments or proteoliposomes containing the membrane protein of interest, a fast solution exchange is used to induce the transport activity of the membrane protein. In the single solution exchange protocol two solutions, one non-activating and one activating solution, are needed. The flow is controlled by pressurized air and a valve and tubing system within a faraday cage. The kinetics of the electrogenic transport activity is obtained via capacitive coupling between the SSM and the proteoliposomes or membrane fragments. The method, therefore, yields only transient currents. The peak current represents the stationary transport activity. The time dependent transporter currents can be reconstructed by circuit analysis. This method is especially suited for prokaryotic transporters or eukaryotic transporters from intracellular membranes, which cannot be investigated by patch clamp or voltage clamp methods. PMID:23711952

  5. Introduction to solid supported membrane based electrophysiology.

    PubMed

    Bazzone, Andre; Costa, Wagner Steuer; Braner, Markus; Călinescu, Octavian; Hatahet, Lina; Fendler, Klaus

    2013-05-11

    The electrophysiological method we present is based on a solid supported membrane (SSM) composed of an octadecanethiol layer chemisorbed on a gold coated sensor chip and a phosphatidylcholine monolayer on top. This assembly is mounted into a cuvette system containing the reference electrode, a chlorinated silver wire. After adsorption of membrane fragments or proteoliposomes containing the membrane protein of interest, a fast solution exchange is used to induce the transport activity of the membrane protein. In the single solution exchange protocol two solutions, one non-activating and one activating solution, are needed. The flow is controlled by pressurized air and a valve and tubing system within a faraday cage. The kinetics of the electrogenic transport activity is obtained via capacitive coupling between the SSM and the proteoliposomes or membrane fragments. The method, therefore, yields only transient currents. The peak current represents the stationary transport activity. The time dependent transporter currents can be reconstructed by circuit analysis. This method is especially suited for prokaryotic transporters or eukaryotic transporters from intracellular membranes, which cannot be investigated by patch clamp or voltage clamp methods.

  6. TNF-α stimulates System A amino acid transport in primary human trophoblast cells mediated by p38 MAPK signaling.

    PubMed

    Aye, Irving L M H; Jansson, Thomas; Powell, Theresa L

    2015-10-01

    Maternal obesity and gestational diabetes mellitus (GDM) increase the risk of delivering infants that are large for gestational age with greater adiposity, who are prone to the development of metabolic disease in childhood and beyond. These maternal conditions are also associated with increased levels of the proinflammatory cytokine TNF-α in maternal tissues and the placenta. Recent evidence suggests that changes in placental amino acid transport contribute to altered fetal growth. TNF-α was previously shown to stimulate System A amino acid transport in primary human trophoblasts (PHTs), however the molecular mechanisms remain unknown. In this study, we tested the hypothesis that TNF-α regulates amino acid uptake in cultured PHTs by a mitogen-activated protein kinase (MAPK)-dependent mechanism. Treatment of PHTs with TNF-α significantly increased System A amino acid transport, as well as Erk and p38 MAPK signaling. Pharmacological antagonism of p38, but not Erk MAPK activity, inhibited TNF-α stimulated System A activity. Silencing of p38 MAPK using siRNA transfections prevented TNF-α stimulated System A transport in PHTs. TNF-α significantly increased the protein expression of System A transporters SNAT1 and SNAT2, but did not affect their mRNA expression. The effects of TNF-α on SNAT1 and SNAT2 protein expression were reversed by p38 MAPK siRNA silencing. In conclusion, TNF-α regulates System A activity through increased SNAT1 and SNAT2 transporter protein expression in PHTs. These findings suggest that p38 MAPK may represent a critical mechanistic link between elevated proinflammatory cytokines and increased placental amino acid transport in obese and GDM pregnancies associated with fetal overgrowth. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  7. The Space Shuttle - A future space transportation system

    NASA Technical Reports Server (NTRS)

    Thompson, R. F.

    1974-01-01

    The objective of the Space Shuttle Program is to achieve an economical space transportation system. This paper provides an introductory review of the considerations which led to the Government decisions to develop the Space Shuttle. The role of a space transportation system is then considered within the context of historical developments in the general field of transportation, followed by a review of the Shuttle system, mission profile, payload categories, and payload accommodations which the Shuttle system will provide, and concludes with a forecast of the systems utilization for space science research and payload planning activity.

  8. Using heterologous expression systems to characterize potassium and sodium transport activities.

    PubMed

    Rodríguez, Alonso; Benito, Begoña; Cagnac, Olivier

    2012-01-01

    The expression of plant transporters in simple well-characterized cell systems is an irreplaceable technique for gaining insights into the kinetic and energetic features of plant transporters. Among all the available expression systems, yeast cells offer the highest simplicity and have the capacity to mimic the in vivo properties of plant transporters. Here, we describe the use of yeast mutants to express K(+) and Na(+) plant transporters and discuss some experimental problems that can produce misleading results.

  9. Comparative molecular biological analysis of membrane transport genes in organisms

    PubMed Central

    Nagata, Toshifumi; Iizumi, Shigemi; Satoh, Kouji

    2008-01-01

    Comparative analyses of membrane transport genes revealed many differences in the features of transport homeostasis in eight diverse organisms, ranging from bacteria to animals and plants. In bacteria, membrane-transport systems depend mainly on single genes encoding proteins involved in an ATP-dependent pump and secondary transport proteins that use H+ as a co-transport molecule. Animals are especially divergent in their channel genes, and plants have larger numbers of P-type ATPase and secondary active transporters than do other organisms. The secondary transporter genes have diverged evolutionarily in both animals and plants for different co-transporter molecules. Animals use Na+ ions for the formation of concentration gradients across plasma membranes, dependent on secondary active transporters and on membrane voltages that in turn are dependent on ion transport regulation systems. Plants use H+ ions pooled in vacuoles and the apoplast to transport various substances; these proton gradients are also dependent on secondary active transporters. We also compared the numbers of membrane transporter genes in Arabidopsis and rice. Although many transporter genes are similar in these plants, Arabidopsis has a more diverse array of genes for multi-efflux transport and for response to stress signals, and rice has more secondary transporter genes for carbohydrate and nutrient transport. Electronic supplementary material The online version of this article (doi:10.1007/s11103-007-9287-z) contains supplementary material, which is available to authorized users. PMID:18293089

  10. A study of characteristics of intercity transportation systems. Phase 1: Definition of transportation comparison methodology

    NASA Technical Reports Server (NTRS)

    English, J. M.; Smith, J. L.; Lifson, M. W.

    1978-01-01

    Decision making in early transportation planning must be responsive to complex value systems representing various policies and objectives. The assessment of alternative transportation concepts during the early initial phases of the system life cycle, when supportive research and technology development activities are defined, requires estimates of transportation, environmental, and socio-economic impacts throughout the system life cycle, which is a period of some 40 or 50 years. A unified methodological framework for comparing intercity passenger and freight transportation systems is described and is extended to include the comparison of long term transportation trends arising from implementation of the various R & D programs. The attributes of existing and future transportation systems are reviewed in order to establish measures for comparison, define value functions, and attribute weightings needed for comparing alternative policy actions for furthering transportation goals. Comparison criteria definitions and an illustrative example are included.

  11. Expression of apical Na(+)-L-glutamine co-transport activity, B(0)-system neutral amino acid co-transporter (B(0)AT1) and angiotensin-converting enzyme 2 along the jejunal crypt-villus axis in young pigs fed a liquid formula

    USDA-ARS?s Scientific Manuscript database

    Gut apical amino acid (AA) transport activity is high at birth and during suckling, thus being essential to maintain luminal nutrient-dependent mucosal growth through providing AA as essential metabolic fuel, substrates and nutrient stimuli for cellular growth. Because system-B(0) Na(+)-neutral AA c...

  12. The ABC of Biofilm Drug Tolerance: the MerR-Like Regulator BrlR Is an Activator of ABC Transport Systems, with PA1874-77 Contributing to the Tolerance of Pseudomonas aeruginosa Biofilms to Tobramycin.

    PubMed

    Poudyal, Bandita; Sauer, Karin

    2018-02-01

    A hallmark of biofilms is their tolerance to killing by antimicrobial agents. In Pseudomonas aeruginosa , biofilm drug tolerance requires the c-di-GMP-responsive MerR transcriptional regulator BrlR. However, the mechanism by which BrlR mediates biofilm drug tolerance has not been elucidated. Here, we demonstrate that BrlR activates the expression of at least 7 ABC transport systems, including the PA1874-PA1875-PA1876-PA1877 (PA1874-77) operon, with chromatin immunoprecipitation and DNA binding assays confirming BrlR binding to the promoter region of PA1874-77. Insertional inactivation of the 7 ABC transport systems rendered P. aeruginosa PAO1 biofilms susceptible to tobramycin or norfloxacin. Susceptibility was linked to drug accumulation, with BrlR contributing to norfloxacin accumulation in a manner dependent on multidrug efflux pumps and the PA1874-77 ABC transport system. Inactivation of the respective ABC transport system, furthermore, eliminated the recalcitrance of biofilms to killing by tobramycin but not norfloxacin, indicating that drug accumulation is not linked to biofilm drug tolerance. Our findings indicate for the first time that BrlR, a MerR-type transcriptional activator, activates genes encoding several ABC transport systems, in addition to multiple multidrug efflux pump genes. Moreover, our data confirm a BrlR target contributing to drug tolerance, likely countering the prevailing dogma that biofilm tolerance arises from a multiplicity of factors. Copyright © 2018 American Society for Microbiology.

  13. Mammalian target of rapamycin signalling modulates amino acid uptake by regulating transporter cell surface abundance in primary human trophoblast cells.

    PubMed

    Rosario, Fredrick J; Kanai, Yoshikatsu; Powell, Theresa L; Jansson, Thomas

    2013-02-01

    Abnormal fetal growth increases the risk for perinatal complications and predisposes for the development of obesity, diabetes and cardiovascular disease later in life. Emerging evidence suggests that changes in placental amino acid transport directly contribute to altered fetal growth. However, the molecular mechanisms regulating placental amino acid transport are largely unknown. Here we combined small interfering (si) RNA-mediated silencing approaches with protein expression/localization and functional studies in cultured primary human trophoblast cells to test the hypothesis that mammalian target of rapamycin complex 1 (mTORC1) and 2 (mTORC2) regulate amino acid transporters by post-translational mechanisms. Silencing raptor (inhibits mTORC1) or rictor (inhibits mTORC2) markedly decreased basal System A and System L amino acid transport activity but had no effect on growth factor-stimulated amino acid uptake. Simultaneous inhibition of mTORC1 and 2 completely inhibited both basal and growth factor-stimulated amino acid transport activity. In contrast, mTOR inhibition had no effect on serotonin transport. mTORC1 or mTORC2 silencing markedly decreased the plasma membrane expression of specific System A (SNAT2, SLC38A2) and System L (LAT1, SLC7A5) transporter isoforms without affecting global protein expression. In conclusion, mTORC1 and mTORC2 regulate human trophoblast amino acid transporters by modulating the cell surface abundance of specific transporter isoforms. This is the first report showing regulation of amino acid transport by mTORC2. Because placental mTOR activity and amino acid transport are decreased in human intrauterine growth restriction our data are consistent with the possibility that dysregulation of placental mTOR plays an important role in the development of abnormal fetal growth.

  14. Assessment of Operational Barriers and Impediments to Transit Use: Transit Information and Scheduling for Major Activity Centers

    DOT National Transportation Integrated Search

    2001-12-01

    The decision to use public transit as a means of alternative transportation is a somewhat complex process. The potential rider must know that a public transportation system is available, how to contact the public transportation system for information...

  15. Intelligent transportation systems for improving traffic energy efficiency and reducing GHG emissions from roadways : a white paper from the National Center for Sustainable Transportation.

    DOT National Transportation Integrated Search

    2015-11-01

    The field of Intelligent Transportation Systems (ITS) has : witnessed significantly increased activity in recent years, : with the application of modern control, communications, : and information technologies to vehicles and roadway : infrastructure....

  16. Applying GPS to enhance understanding of transport-related physical activity.

    PubMed

    Duncan, Mitch J; Badland, Hannah M; Mummery, W Kerry

    2009-09-01

    The purpose of the paper is to review the utility of the global positioning system (GPS) in the study of health-related physical activity. The paper draws from existing literature to outline the current work performed using GPS to examine transport-related physical activity, with a focus on the relative utility of the approach when combined with geographic information system (GIS) and other data sources including accelerometers. The paper argues that GPS, especially when used in combination with GIS and accelerometery, offers great promise in objectively measuring and studying the relationship of numerous environmental attributes to human behaviour in terms of physical activity and transport-related activity. Limitations to the use of GPS for the purpose of monitoring health-related physical activity are presented, and recommendations for future avenues of research are discussed.

  17. Transportation Systems. Curriculum Guide for Technology Education.

    ERIC Educational Resources Information Center

    Chastain, Gary K.

    This curriculum guide for a 1-semester or 1-year course in transportation provides activities that show and explain many of the occupations, devices, and systems that are related to transportation on land, water, air, and space. The guide contains competencies (task lists), student competency records, and management sheets. Management sheets,…

  18. 14 CFR 25.672 - Stability augmentation and automatic and power-operated systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Control Systems § 25.672 Stability augmentation and automatic and power-operated systems. If the... the pilot were not aware of the failure. Warning systems must not activate the control systems. (b...

  19. 14 CFR 25.672 - Stability augmentation and automatic and power-operated systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Control Systems § 25.672 Stability augmentation and automatic and power-operated systems. If the... the pilot were not aware of the failure. Warning systems must not activate the control systems. (b...

  20. 14 CFR 25.672 - Stability augmentation and automatic and power-operated systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Control Systems § 25.672 Stability augmentation and automatic and power-operated systems. If the... the pilot were not aware of the failure. Warning systems must not activate the control systems. (b...

  1. 14 CFR 25.672 - Stability augmentation and automatic and power-operated systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Control Systems § 25.672 Stability augmentation and automatic and power-operated systems. If the... the pilot were not aware of the failure. Warning systems must not activate the control systems. (b...

  2. Functional significance of the E loop, a novel motif conserved in the lantibiotic immunity ATP-binding cassette transport systems.

    PubMed

    Okuda, Ken-ichi; Yanagihara, Sae; Sugayama, Tomomichi; Zendo, Takeshi; Nakayama, Jiro; Sonomoto, Kenji

    2010-06-01

    Lantibiotics are peptide-derived antibacterial substances produced by some Gram-positive bacteria and characterized by the presence of unusual amino acids, like lanthionines and dehydrated amino acids. Because lantibiotic producers may be attacked by self-produced lantibiotics, they express immunity proteins on the cytoplasmic membrane. An ATP-binding cassette (ABC) transport system mediated by the LanFEG protein complex is a major system in lantibiotic immunity. Multiple-sequence alignment analysis revealed that LanF proteins contain the E loop, a variant of the Q loop, which is a well-conserved motif in the nucleotide-binding domains (NBDs) of general ABC transporters. To elucidate E loop function, we introduced a mutation in the NukF protein, which is involved in the nukacin-ISK-1 immunity system. Amino acid replacement of glutamic acid in the E loop with glutamine (E85Q) resulted in slight decreases in the immunity level and transport activity. Additionally, the E85A mutation severely impaired the immunity level and transport activity. On the other hand, ATPase activities of purified E85Q and E85A mutants were almost similar to that of the wild type. These results suggested that the E loop found in ABC transporters involved in lantibiotic immunity plays a significant role in the function of these transporters, especially in the structural change of transmembrane domains.

  3. Mechanistic kinetic modeling generates system-independent P-glycoprotein mediated transport elementary rate constants for inhibition and, in combination with 3D SIM microscopy, elucidates the importance of microvilli morphology on P-glycoprotein mediated efflux activity.

    PubMed

    Ellens, Harma; Meng, Zhou; Le Marchand, Sylvain J; Bentz, Joe

    2018-06-01

    In vitro transporter kinetics are typically analyzed by steady-state Michaelis-Menten approximations. However, no clear evidence exists that these approximations, applied to multiple transporters in biological membranes, yield system-independent mechanistic parameters needed for reliable in vivo hypothesis generation and testing. Areas covered: The classical mass action model has been developed for P-glycoprotein (P-gp) mediated transport across confluent polarized cell monolayers. Numerical integration of the mass action equations for transport using a stable global optimization program yields fitted elementary rate constants that are system-independent. The efflux active P-gp was defined by the rate at which P-gp delivers drugs to the apical chamber, since as much as 90% of drugs effluxed by P-gp partition back into nearby microvilli prior to reaching the apical chamber. The efflux active P-gp concentration was 10-fold smaller than the total expressed P-gp for Caco-2 cells, due to their microvilli membrane morphology. The mechanistic insights from this analysis are readily extrapolated to P-gp mediated transport in vivo. Expert opinion: In vitro system-independent elementary rate constants for transporters are essential for the generation and validation of robust mechanistic PBPK models. Our modeling approach and programs have broad application potential. They can be used for any drug transporter with minor adaptations.

  4. An Abiotic Glass-Bead Collector Exhibiting Active Transport

    NASA Astrophysics Data System (ADS)

    Goto, Youhei; Kanda, Masato; Yamamoto, Daigo; Shioi, Akihisa

    2015-09-01

    Animals relocate objects as needed by active motion. Active transport is ubiquitous in living organisms but has been difficult to realize in abiotic systems. Here we show that a self-propelled droplet can gather scattered beads toward one place on a floor and sweep it clean. This is a biomimetic active transport with loadings and unloadings, because the transport was performed by a carrier and the motion of the carrier was maintained by the energy of the chemical reaction. The oil droplet produced fluctuation of the local number density of the beads on the floor, followed by its autocatalytic growth. This mechanism may inspire the technologies based on active transport wherein chemical and physical substances migrate as in living organisms.

  5. 14 CFR 29.672 - Stability augmentation, automatic, and power-operated systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.672 Stability augmentation, automatic, and power-operated systems. If the... unsafe condition if the pilot is unaware of the failure. Warning systems must not activate the control...

  6. Functional analysis of choline transporters in rheumatoid arthritis synovial fibroblasts.

    PubMed

    Seki, Masayuki; Kawai, Yuiko; Ishii, Chikanao; Yamanaka, Tsuyoshi; Odawara, Masato; Inazu, Masato

    2017-11-01

    In this study, we examined the functional characteristics of choline uptake and sought to identify the transporters in rheumatoid arthritis synovial fibroblasts (RASFs). The expression of choline transporters was evaluated by quantitative real-time PCR, western blotting, and immunocytochemistry. Time course, Na + -dependency, and kinetics of [ 3 H]choline uptake were investigated. Effects of cationic drugs on the uptake of [ 3 H]choline, cell viability, and caspase-3/7 activity were also examined. Finally, we investigated the influence of choline uptake inhibitor, hemicholinium-3 (HC-3), and choline deficiency on cell viability and caspase-3/7 activity. Choline transporter-like protein 1 (CTL1) and CTL2 mRNA and protein were highly expressed in RASFs and were localized to the plasma membrane. [ 3 H]Choline uptake occurred via a Na + -independent and pH-dependent transport system. The cells have two different [ 3 H]choline transport systems, high- and low-affinity. Various organic cations, HC-3 and choline deficiency inhibited both [ 3 H]choline uptake and cell viability, and enhanced the caspase-3/7 activity. The functional inhibition of choline transporters could promote apoptotic cell death. In RASFs, [ 3 H]choline uptake was significantly increased compared with that in OASFs without a change in gene expression. These results suggest that CTL1 (high-affinity) and CTL2 (low-affinity) are highly expressed in RASFs and choline may be transported by a choline/H +  antiport system. Identification of this CTL1- and CTL2-mediated choline transport system should provide a potential new target for RA therapy.

  7. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The Current and Advanced Technology ACT control system definition tasks of the Integrated Application of Active Controls (IAAC) Technology project within the Energy Efficient Transport Program are summarized. The systems mechanize six active control functions: (1) pitch augmented stability; (2) angle of attack limiting; (3) lateral/directional augmented stability; (4) gust load alleviation; (5) maneuver load control; and (6) flutter mode control. The redundant digital control systems meet all function requirements with required reliability and declining weight and cost as advanced technology is introduced.

  8. Development of risk models for Florida's bridge management system.

    DOT National Transportation Integrated Search

    2013-06-01

    Florida Department of Transportation (FDOT) has been actively implementing the American Association of State Highway Transportation Officials (AASHTO) Pontis Bridge Management System (BMS), recently renamed AASHTOWare Bridge Management (BrM), to supp...

  9. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study. Volume 2: Appendices

    NASA Technical Reports Server (NTRS)

    Hanks, G. W.; Shomber, H. A.; Dethman, H. A.; Gratzer, L. B.; Maeshiro, A.; Gangsaas, D.; Blight, J. D.; Buchan, S. M.; Crumb, C. B.; Dorwart, R. J.

    1981-01-01

    The current status of the Active Controls Technology (ACT) for the advanced subsonic transport project is investigated through analysis of the systems technical data. Control systems technologies under examination include computerized reliability analysis, pitch axis fly by wire actuator, flaperon actuation system design trade study, control law synthesis and analysis, flutter mode control and gust load alleviation analysis, and implementation of alternative ACT systems. Extensive analysis of the computer techniques involved in each system is included.

  10. In-Space Transportation for GEO Space Solar Power Satellites

    NASA Technical Reports Server (NTRS)

    Martin, James A.; Donnahue, Benjamin B.; Henley, Mark W.

    1999-01-01

    This report summarizes results of study tasks to evaluate design options for in-space transportation of geostationary Space Solar Power Satellites. Referring to the end-to-end architecture studies performed in 1988, this current activity focuses on transportation of Sun Tower satellite segments from an initial low Earth orbit altitude to a final position in geostationary orbit (GEO; i.e., 35,786 km altitude, circular, equatorial orbit). This report encompasses study activity for In-Space Transportation of GEO Space Solar Power (SSP) Satellites including: 1) assessment of requirements, 2) design of system concepts, 3) comparison of alternative system options, and 4) assessment of potential derivatives.

  11. Variable stoichiometry in active ion transport: theoretical analysis of physiological consequences.

    PubMed

    Johnson, E A; Tanford, C; Reynolds, J A

    1985-08-01

    Active ion transport systems with fixed stoichiometry are subject to a thermodynamic limit on the ion concentration gradients that they can generate and maintain, and their net rates of transport must inevitably decrease as this limit is approached. The capability to vary stoichiometry might thus be physiologically advantageous: a shift to lower stoichiometry (fewer ions pumped per reaction cycle) at increasing thermodynamic load could increase the limit on the supportable concentration gradient and could accelerate the rate of transport under high-load conditions. Here we present a theoretical and numerical analysis of this possibility, using the sarcoplasmic reticulum ATP-driven Ca pump as the example. It is easy to introduce alternate pathways into the reaction cycle for this system to shift the stoichiometry (Ca2+/ATP) from the normal value of 2:1 to 1:1, but it cannot be done without simultaneous generation of a pathway for uncoupled leak of Ca2+ across the membrane. This counteracts the advantageous effect of the change in transport stoichiometry and a physiologically useful rate acceleration cannot be obtained. This result is likely to be generally applicable to most active transport systems.

  12. Variable stoichiometry in active ion transport: theoretical analysis of physiological consequences.

    PubMed Central

    Johnson, E A; Tanford, C; Reynolds, J A

    1985-01-01

    Active ion transport systems with fixed stoichiometry are subject to a thermodynamic limit on the ion concentration gradients that they can generate and maintain, and their net rates of transport must inevitably decrease as this limit is approached. The capability to vary stoichiometry might thus be physiologically advantageous: a shift to lower stoichiometry (fewer ions pumped per reaction cycle) at increasing thermodynamic load could increase the limit on the supportable concentration gradient and could accelerate the rate of transport under high-load conditions. Here we present a theoretical and numerical analysis of this possibility, using the sarcoplasmic reticulum ATP-driven Ca pump as the example. It is easy to introduce alternate pathways into the reaction cycle for this system to shift the stoichiometry (Ca2+/ATP) from the normal value of 2:1 to 1:1, but it cannot be done without simultaneous generation of a pathway for uncoupled leak of Ca2+ across the membrane. This counteracts the advantageous effect of the change in transport stoichiometry and a physiologically useful rate acceleration cannot be obtained. This result is likely to be generally applicable to most active transport systems. PMID:3860866

  13. Fluorescent sensors reporting the activity of ammonium transceptors in live cells

    DOE PAGES

    De Michele, Roberto; Ast, Cindy; Loqué, Dominique; ...

    2013-07-02

    Ammonium serves as key nitrogen source and metabolic intermediate, yet excess causes toxicity. Ammonium uptake is mediated by ammonium transporters, whose regulation is poorly understood. While transport can easily be characterized in heterologous systems, measuring transporter activity in vivo remains challenging. Here we developed a simple assay for monitoring activity in vivo by inserting circularly-permutated GFP into conformation-sensitive positions of two plant and one yeast ammonium transceptors (‘AmTrac’ and ‘MepTrac’). Addition of ammonium to yeast cells expressing the sensors triggered concentration-dependent fluorescence intensity (FI) changes that strictly correlated with the activity of the transporter. Fluorescence-based activity sensors present a novelmore » technology for monitoring the interaction of the transporters with their substrates, the activity of transporters and their regulation in vivo, which is particularly valuable in the context of analytes for which no radiotracers exist, as well as for cell-specific and subcellular transport processes that are otherwise difficult to track.« less

  14. Single-cell-based system to monitor carrier driven cellular auxin homeostasis

    PubMed Central

    2013-01-01

    Background Abundance and distribution of the plant hormone auxin play important roles in plant development. Besides other metabolic processes, various auxin carriers control the cellular level of active auxin and, hence, are major regulators of cellular auxin homeostasis. Despite the developmental importance of auxin transporters, a simple medium-to-high throughput approach to assess carrier activities is still missing. Here we show that carrier driven depletion of cellular auxin correlates with reduced nuclear auxin signaling in tobacco Bright Yellow-2 (BY-2) cell cultures. Results We developed an easy to use transient single-cell-based system to detect carrier activity. We use the relative changes in signaling output of the auxin responsive promoter element DR5 to indirectly visualize auxin carrier activity. The feasibility of the transient approach was demonstrated by pharmacological and genetic interference with auxin signaling and transport. As a proof of concept, we provide visual evidence that the prominent auxin transport proteins PIN-FORMED (PIN)2 and PIN5 regulate cellular auxin homeostasis at the plasma membrane and endoplasmic reticulum (ER), respectively. Our data suggest that PIN2 and PIN5 have different sensitivities to the auxin transport inhibitor 1-naphthylphthalamic acid (NPA). Also the putative PIN-LIKES (PILS) auxin carrier activity at the ER is insensitive to NPA in our system, indicating that NPA blocks intercellular, but not intracellular auxin transport. Conclusions This single-cell-based system is a useful tool by which the activity of putative auxin carriers, such as PINs, PILS and WALLS ARE THIN1 (WAT1), can be indirectly visualized in a medium-to-high throughput manner. Moreover, our single cell system might be useful to investigate also other hormonal signaling pathways, such as cytokinin. PMID:23379388

  15. 49 CFR 234.225 - Activation of warning system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Activation of warning system. 234.225 Section 234....225 Activation of warning system. A highway-rail grade crossing warning system shall be maintained to activate in accordance with the design of the warning system, but in no event shall it provide less than 20...

  16. 49 CFR 234.225 - Activation of warning system.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Activation of warning system. 234.225 Section 234....225 Activation of warning system. A highway-rail grade crossing warning system shall be maintained to activate in accordance with the design of the warning system, but in no event shall it provide less than 20...

  17. 49 CFR 234.225 - Activation of warning system.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Activation of warning system. 234.225 Section 234....225 Activation of warning system. A highway-rail grade crossing warning system shall be maintained to activate in accordance with the design of the warning system, but in no event shall it provide less than 20...

  18. 49 CFR 234.225 - Activation of warning system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Activation of warning system. 234.225 Section 234... Maintenance, Inspection, and Testing Maintenance Standards § 234.225 Activation of warning system. A highway-rail grade crossing warning system shall be maintained to activate in accordance with the design of the...

  19. 49 CFR 234.225 - Activation of warning system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Activation of warning system. 234.225 Section 234... Maintenance, Inspection, and Testing Maintenance Standards § 234.225 Activation of warning system. A highway-rail grade crossing warning system shall be maintained to activate in accordance with the design of the...

  20. Air transportation noise technology overview

    NASA Technical Reports Server (NTRS)

    Maggin, B.; Chestnutt, D.

    1973-01-01

    The NASA and DOT technology program planning for quieter air transportation systems is reviewed. To put this planning in context, the nature of the noise problem and the projected nature of the air transportation fleet are identified. The technology program planning reviewed here is discussed in relation to the following areas of activity: systems analysis, community acceptance, basic research and technology, and the various classes of civil aircraft, i.e. existing and advanced transports, powered-lift transports, and general aviation.

  1. Space transportation nodes assumptions and requirements: Lunar base systems study task 2.1

    NASA Technical Reports Server (NTRS)

    Kahn, Taher Ali; Simonds, Charles H.; Stump, William R.

    1988-01-01

    The Space Transportation Nodes Assumptions and Requirements task was performed as part of the Advanced Space Transportation Support Contract, a NASA Johnson Space Center (JSC) study intended to provide planning for a Lunar Base near the year 2000. The original task statement has been revised to satisfy the following queries: (1) What vehicles are to be processed at the transportation node; (2) What is the flow of activities involved in a vehicle passing through the node; and (3) What node support resources are necessary to support a lunar scenario traffic model composed of a mix of vehicles in an active flight schedule. The Lunar Base Systems Study is concentrating on the initial years of the Phase 2 Lunar Base Scenario. The study will develop the first five years of that phase in order to define the transportation and surface systems (including mass, volumes, power requirements, and designs).

  2. Isolation of Plasma Membrane Vesicles from Mouse Placenta at Term and Measurement of System A and System β Amino Acid Transporter Activity

    PubMed Central

    Kusinski, L.C.; Jones, C.J.P.; Baker, P.N.; Sibley, C.P.; Glazier, J.D.

    2010-01-01

    Placental amino acid transport is essential for optimal fetal growth and development, with a reduced fetal provision of amino acids being implicated as a potential cause of fetal growth restriction (FGR). Understanding placental insufficiency related FGR has been aided by the development of mouse models that have features of the human disease. However, to take maximal advantage of these, methods are required to study placental function in the mouse. Here, we report a method to isolate plasma membrane vesicles from mouse placenta near-term and have used these to investigate two amino acid transporters, systems A and β, the activities of which are reduced in human placental microvillous plasma membrane (MVM) vesicles from FGR pregnancies. Plasma membrane vesicles were isolated at embryonic day 18 by a protocol involving homogenisation, MgCl2 precipitation and centrifugation. Vesicles were enriched 11.3 ± 0.5-fold in alkaline phosphatase activity as compared to initial homogenate, with minimal intracellular organelle contamination as judged by marker analyses. Cytochemistry revealed alkaline phosphatase was localised between trophoblast layers I and II, with intense reaction product deposited on the maternal-facing plasma membrane of layer II, suggesting that vesicles were derived from this trophoblast membrane. System A and system β activity in mouse placental vesicles, measured as Na+-dependent uptake of 14C-methylaminoisobutyric acid (MeAIB) and 3H-taurine respectively confirmed localisation of these transporters to the maternal-facing plasma membrane of layer II. Comparison to human placental MVM showed that system A activity was comparable at initial rate between species whilst system β activity was significantly lower in mouse. This mirrored the lower expression of TAUT observed in mouse placental vesicles. We conclude that syncytiotrophoblast layer II-derived plasma membrane vesicles can be isolated and used to examine transporter function. PMID:19954844

  3. Improving transportation systems management and operations (TSM&O), capability maturity model workshop white paper : systems and technology.

    DOT National Transportation Integrated Search

    2015-04-01

    Research done through the Second Strategic Highway Research Program (SHRP 2) determined that agencies with the most effective transportation systems management and operations (TSM&O) activities were differentiated not by budgets or technical skills a...

  4. Transportation Planning and ITS: Putting the Pieces Together

    DOT National Transportation Integrated Search

    2013-11-01

    Both the Dynamic Mobility Applications (DMA) and Active Transportation and Demand Management (ATDM) Programs have similar overarching goals to improve surface transportation system efficiency and individual traveler mobility. However, each program ha...

  5. Recessive constitutive mutant Chinese hamster ovary cells (CHO-K1) with an altered A system for amino acid transport and the mechanism of gene regulation of the A system.

    PubMed Central

    Moffett, J; Englesberg, E

    1984-01-01

    Chinese hamster ovary cells (CHO-K1) starved for 24 h for amino acids show a severalfold increase in velocity of proline transport through the A system (Vmax is five times that of unstarved cells). This increase is inhibited by cycloheximide, actinomycin D, N-methyl-alpha-amino isobutyric acid (MeAIB, a non-metabolizable specific A system amino acid analog), and by other amino acids that are generally transported by the A system. However, transport by the A system is not a prerequisite for this repression, and all compounds that have affinity for the A system do not necessarily act as "co-repressors." The addition of proline, MeAIB, or other amino acids, as described above, to derepressed cells results in a rapid decrease in A system activity. As shown with proline and MeAIB, this decrease in activity is in part due to a rapid trans-inhibition and a slow, irreversible inactivation of the A system. Neither process is inhibited by cycloheximide or actinomycin D. Alanine antagonizes the growth of CHO-K1 pro cells by preventing proline transport, and alanine-resistant mutants (alar) have been isolated (Moffett et al., Somatic Cell Genet. 9:189-213, 1983). alar2 and alar4 are partial and full constitutive mutants for the A system and have two and six times the Vmax for proline uptake by the A system, respectively. The A system in alar4 is also immune to the co-repressor-induced inactivation. Both alar2 and alar4 phenotypes are recessive. Alar3 shows an increase in Vmax and Km for proline transport through the A system, and this phenotype is codominant. All three mutants have a pleiotropic effect, producing increases in activity of the ASC and P systems of amino acid transport. This increase is not due to an increase in the Na+ gradient. The ASC and P phenotypes behave similarly to the A system in hybrids. A model has been proposed incorporating these results. PMID:6538929

  6. Characteristics of urban transportation systems. A handbook for transportation planners

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Not Available

    1975-05-01

    The objective of the handbook, specifically for use by transportation planners in the evaluation of alternative systems, is to provide a single simplified reference source which characterizes the most important performance characteristics of the following contemporary urban transportation systems: (1) rail (commuter, rapid, and light); (2) local bus and bus rapid transit; (3) automobile-highway system (automobiles and other vehicles); (4) pedestrian assistance systems; and (5) activity center systems--people mover systems that have been installed at airports, zoos, amusement parks, etc. The handbook assesses the supply or performance aspect of urban transportation dealing with passenger demand implicitly. Seven supply parameters studiedmore » are: speed, capacity (service volume), operating cost (vehicle), energy consumption (vehicle or source), pollution, capital cost, and accident frequency.« less

  7. America's container ports : freight hubs that connect our nation to global markets

    DOT National Transportation Integrated Search

    2009-06-01

    The U.S. marine transportation system continues to handle large volumes of domestic and international : freight in support of the nations economic activities. The demand for freight transportation : responds to trends in global economic activity a...

  8. Na-coupled bicarbonate transporters of the Slc4 family in the nervous system: function, localization, and relevance to neurologic function

    PubMed Central

    Majumdar, Debeshi; Bevensee, Mark O.

    2010-01-01

    Many cellular processes including neuronal activity are sensitive to changes in intracellular and/or extracellular pH— both of which are regulated by acid-base transporter activity. HCO3−-dependent transporters are particularly potent regulators of intracellular pH in neurons and astrocytes, and also contribute to the composition of the cerebrospinal fluid (CSF). The molecular physiology of HCO3− transporters has advanced considerably over the past ~14 years as investigators have cloned and characterized the function and localization of many Na-Coupled Bicarbonate Transporters of the Slc4 family (NCBTs). In this review, we provide an updated overview of the function and localization of NCBTs in the nervous system. Multiple NCBTs are expressed in neurons and astrocytes in various brain regions, as well as in epithelial cells of the choroid plexus. Characteristics of human patients with SLC4 gene mutations/deletions and results from recent studies on mice with Slc4 gene disruptions highlight the functional importance of NCBTs in neuronal activity, somatosensory function, and CSF production. Furthermore, energy-deficient states (e.g., hypoxia and ischemia) lead to altered expression and activity of NCBTs. Thus, recent studies expand our understanding of the role of NCBTs in regulating the pH and ionic composition of the nervous system that can modulate neuronal activity. PMID:20884330

  9. Bureau of Land Management Transportation Brochure

    DOT National Transportation Integrated Search

    2018-02-01

    Each fiscal year, Congress appropriates the BLM annual funding for land management, resource management, and many other activities, some of which are used for the BLMs transportation system. The general funding that is used for transportation prov...

  10. 48 CFR 47.305 - Solicitation provisions, contract clauses, and transportation factors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., and award phases of the acquisition process (see 47.105). (b) To the extent feasible, activities shall..., contract clauses, and transportation factors. 47.305 Section 47.305 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACT MANAGEMENT TRANSPORTATION Transportation in Supply Contracts 47...

  11. 48 CFR 47.305 - Solicitation provisions, contract clauses, and transportation factors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., and award phases of the acquisition process (see 47.105). (b) To the extent feasible, activities shall..., contract clauses, and transportation factors. 47.305 Section 47.305 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACT MANAGEMENT TRANSPORTATION Transportation in Supply Contracts 47...

  12. Transportation and public health.

    PubMed

    Litman, Todd

    2013-01-01

    This article investigates various ways that transportation policy and planning decisions affect public health and better ways to incorporate public health objectives into transport planning. Conventional planning tends to consider some public health impacts, such as crash risk and pollution emissions measured per vehicle-kilometer, but generally ignores health problems resulting from less active transport (reduced walking and cycling activity) and the additional crashes and pollution caused by increased vehicle mileage. As a result, transport agencies tend to undervalue strategies that increase transport system diversity and reduce vehicle travel. This article identifies various win-win strategies that can help improve public health and other planning objectives.

  13. Colloidal transport by active filaments

    NASA Astrophysics Data System (ADS)

    Manna, Raj Kumar; Kumar, P. B. Sunil; Adhikari, R.

    2017-01-01

    Enhanced colloidal transport beyond the limit imposed by diffusion is usually achieved through external fields. Here, we demonstrate the ballistic transport of a colloidal sphere using internal sources of energy provided by an attached active filament. The latter is modeled as a chain of chemo-mechanically active beads connected by potentials that enforce semi-flexibility and self-avoidance. The fluid flow produced by the active beads and the forces they mediate are explicitly taken into account in the overdamped equations of motion describing the colloid-filament assembly. The speed and efficiency of transport depend on the dynamical conformational states of the filament. We characterize these states using filament writhe as an order parameter and identify ones yielding maxima in speed and efficiency of transport. The transport mechanism reported here has a remarkable resemblance to the flagellar propulsion of microorganisms which suggests its utility in biomimetic systems.

  14. Activation energy-activation volume master plots for ion transport behavior in polymer electrolytes and supercooled molten salts.

    PubMed

    Ingram, Malcolm D; Imrie, Corrie T; Stoeva, Zlatka; Pas, Steven J; Funke, Klaus; Chandler, Howard W

    2005-09-08

    We demonstrate the use of activation energy versus activation volume "master plots" to explore ion transport in typical fragile glass forming systems exhibiting non-Arrhenius behavior. These systems include solvent-free salt complexes in poly(ethylene oxide) (PEO) and low molecular weight poly(propylene oxide) (PPO) and molten 2Ca(NO3)2.3KNO3 (CKN). Plots showing variations in apparent activation energy EA versus apparent activation volume VA are straight lines with slopes given by M = DeltaEA/DeltaVA. A simple ion transport mechanism is described where the rate determining step involves a dilatation (expressed as VA) around microscopic cavities and a corresponding work of expansion (EA). The slopes of the master plots M are equated to internal elastic moduli, which vary from 1.1 GPa for liquid PPO to 5.0 GPa for molten CKN on account of differing intermolecular forces in these materials.

  15. Transportation noise and recreational lands

    DOT National Transportation Integrated Search

    2002-08-20

    An active and widely distributed transportation system is virtually a requirement for and a hallmark of countries that have a vigorous economy. As this conference demonstrates, one of the products of such a system is noise, and it is most certainly t...

  16. Requirement for Coenzyme Q in Plasma Membrane Electron Transport

    NASA Astrophysics Data System (ADS)

    Sun, I. L.; Sun, E. E.; Crane, F. L.; Morre, D. J.; Lindgren, A.; Low, H.

    1992-12-01

    Coenzyme Q is required in the electron transport system of rat hepatocyte and human erythrocyte plasma membranes. Extraction of coenzyme Q from the membrane decreases NADH dehydrogenase and NADH:oxygen oxidoreductase activity. Addition of coenzyme Q to the extracted membrane restores the activity. Partial restoration of activity is also found with α-tocopherylquinone, but not with vitamin K_1. Analogs of coenzyme Q inhibit NADH dehydrogenase and oxidase activity and the inhibition is reversed by added coenzyme Q. Ferricyanide reduction by transmembrane electron transport from HeLa cells is inhibited by coenzyme Q analogs and restored with added coenzyme Q10. Reduction of external ferricyanide and diferric transferrin by HeLa cells is accompanied by proton release from the cells. Inhibition of the reduction by coenzyme Q analogs also inhibits the proton release, and coenzyme Q10 restores the proton release activity. Trans-plasma membrane electron transport stimulates growth of serum-deficient cells, and added coenzyme Q10 increases growth of HeLa (human adenocarcinoma) and BALB/3T3 (mouse fibroblast) cells. The evidence is consistent with a function for coenzyme Q in a trans-plasma membrane electron transport system which influences cell growth.

  17. Subsurface flow pathway dynamics in the active layer of coupled permafrost-hydrogeological systems under seasonal and annual temperature variability.

    NASA Astrophysics Data System (ADS)

    Frampton, Andrew

    2017-04-01

    There is a need for improved understanding of the mechanisms controlling subsurface solute transport in the active layer in order to better understand permafrost-hydrological-carbon feedbacks, in particular with regards to how dissolved carbon is transported in coupled surface and subsurface terrestrial arctic water systems under climate change. Studying solute transport in arctic systems is also relevant in the context of anthropogenic pollution which may increase due to increased activity in cold region environments. In this contribution subsurface solute transport subject to ground surface warming causing permafrost thaw and active layer change is studied using a physically based model of coupled cryotic and hydrogeological flow processes combined with a particle tracking method. Changes in subsurface water flows and solute transport travel times are analysed for different modelled geological configurations during a 100-year warming period. Results show that for all simulated cases, the minimum and mean travel times increase non-linearly with warming irrespective of geological configuration and heterogeneity structure. The timing of the start of increase in travel time depends on heterogeneity structure, combined with the rate of permafrost degradation that also depends on material thermal and hydrogeological properties. These travel time changes are shown to depend on combined warming effects of increase in pathway length due to deepening of the active layer, reduced transport velocities due to a shift from horizontal saturated groundwater flow near the surface to vertical water percolation deeper into the subsurface, and pathway length increase and temporary immobilization caused by cryosuction-induced seasonal freeze cycles. The impact these change mechanisms have on solute and dissolved substance transport is further analysed by integrating pathway analysis with a Lagrangian approach, incorporating considerations for both dissolved organic and inorganic carbon releases. Further model development challenges are also highlighted and discussed, including coupling between subsurface and surface runoff, soil deformations, as well as site applications and larger system scales.

  18. Sustainable transportation according to certification systems: A viability analysis based on neighborhood size and context relevance

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gouda, Amr Ah., E-mail: amr.gouda@eng.asu.edu.eg; Architecture Department, Faculty of Engineering, Ain Shams University, 1 Sarayat St., Abassia, Cairo; Masoumi, Houshmand E.

    Urban sustainability certification (USC) systems comprehensively assess and benchmark the sustainability of neighborhoods, communities, etc. However, it is important to understand what USCs mean by neighborhoods and communities in terms of definition and their certified developments' size. This study focuses on sustainable transportation and its measures in USCs in order to discern: how relevant are these measures to the varied local conditions, especially in developing countries? And whether they can generate palpable benefits vis-à-vis the certified developments' site areas. Taking descriptive analysis methods, this study focuses on four prominent USCs, namely, LEED for Neighborhood Development, BREEAM Communities, CASBEE for Urbanmore » Development, and The Pearl Community Rating System. The four USCs prescribed multiple measures for sustainable transportation, particularly in favor of active transportation and public transportation. However, the relatively small size of their citified developments and the varying transportation conditions among different contexts attenuate the viability and relevance of the advocated measures for both modes. In order to yield more benefits, USCs should underscore the integrative nature of neighborhoods and communities, and transportation within their prescribed criteria and measures. Moreover, sustainable transportation as a theme should be tailored to the local conditions rather than being adopted or adapted from global USCs. - Highlights: • Transportation measures in four prominent certification systems were investigated. • Most certified neighborhoods, communities and developments have small site areas. • Certifications are insensitive to realities of transport in developing countries. • Benefits from advocating active transport only within certified areas are minimal. • Certifications devalue the integrative nature of neighborhoods and transportation.« less

  19. Human Erythrocyte Glucose Transporter: Normal Asymmetric Orientation and Function in Liposomes

    NASA Astrophysics Data System (ADS)

    Chen, Chia-Chen; Kurokawa, Tomonori; Shaw, Shyh-Yu; Tillotson, Loyal G.; Kalled, Susan; Isselbacher, Kurt J.

    1986-04-01

    The transport function and orientation of the reconstituted human erythrocyte glucose transporter was studied with liposomes made with bovine brain lipid or Escherichia coli lipid. Reconstitution was achieved by a simple octyl glucoside dilution method. The reconstituted transporters with either lipid showed identical counterflow transport activity, the same response to various inhibitors, and characteristic cytochalasin B (CB) labeling. Functional location and purification of the glucose transporter was performed by using gel-permeation high-performance liquid chromatography with octyl glucoside-containing buffer. The reconstituted transport activity was associated only with band 4.5 protein (preactin) and not with band 3 protein. Both CB binding and transport function of the reconstituted transporters were resistant to trypsin but susceptible to chymotrypsin digestion. However, both trypsin and chymotrypsin treatment of unsealed ghosts completely eliminated the CB labeling and transport function of the glucose transporter. In our reconstitution system the glucose transporters maintained a normal asymmetrical (rightside-out) orientation and good transport function. A specific monoclonal antibody against the glucose transporter inhibited CB labeling of the transporters on unsealed ghosts. This was not found with the reconstituted system; however, after freeze-thawing there was a significant inhibition of CB binding by the antibody. These findings suggest that the CB-binding site of the reconstituted transporter is on the inner side of the proteoliposomes.

  20. UNC-16 (JIP3) Acts Through Synapse-Assembly Proteins to Inhibit the Active Transport of Cell Soma Organelles to Caenorhabditis elegans Motor Neuron Axons

    PubMed Central

    Edwards, Stacey L.; Morrison, Logan M.; Yorks, Rosalina M.; Hoover, Christopher M.; Boominathan, Soorajnath; Miller, Kenneth G.

    2015-01-01

    The conserved protein UNC-16 (JIP3) inhibits the active transport of some cell soma organelles, such as lysosomes, early endosomes, and Golgi, to the synaptic region of axons. However, little is known about UNC-16’s organelle transport regulatory function, which is distinct from its Kinesin-1 adaptor function. We used an unc-16 suppressor screen in Caenorhabditis elegans to discover that UNC-16 acts through CDK-5 (Cdk5) and two conserved synapse assembly proteins: SAD-1 (SAD-A Kinase), and SYD-2 (Liprin-α). Genetic analysis of all combinations of double and triple mutants in unc-16(+) and unc-16(−) backgrounds showed that the three proteins (CDK-5, SAD-1, and SYD-2) are all part of the same organelle transport regulatory system, which we named the CSS system based on its founder proteins. Further genetic analysis revealed roles for SYD-1 (another synapse assembly protein) and STRADα (a SAD-1-interacting protein) in the CSS system. In an unc-16(−) background, loss of the CSS system improved the sluggish locomotion of unc-16 mutants, inhibited axonal lysosome accumulation, and led to the dynein-dependent accumulation of lysosomes in dendrites. Time-lapse imaging of lysosomes in CSS system mutants in unc-16(+) and unc-16(−) backgrounds revealed active transport defects consistent with the steady-state distributions of lysosomes. UNC-16 also uses the CSS system to regulate the distribution of early endosomes in neurons and, to a lesser extent, Golgi. The data reveal a new and unprecedented role for synapse assembly proteins, acting as part of the newly defined CSS system, in mediating UNC-16’s organelle transport regulatory function. PMID:26354976

  1. Technology: Manufacturing, Transportation, Construction, Communication.

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Public Instruction, Raleigh. Div. of Vocational Education.

    The technology-based student activities in this curriculum resource book are intended to be incorporated into any industrial arts/technology education program. The activities are classified according to one of four technological systems--construction, communications, manufacturing, and transportation. Within the four parts of the guide, individual…

  2. Urban Transportation Renewal.

    ERIC Educational Resources Information Center

    Wolter, Kurt A.; Foster, Patrick N.

    1995-01-01

    Describes a learning activity that involves planning a community and then altering the transportation system to meet new specifications. Includes the rationale for the activity, how it fits into the technology education curriculum, and how it was implemented to fit a variety of age and grade levels. (JOW)

  3. Specific character of sustainable innovative development of transport construction in self-regulation conditions

    NASA Astrophysics Data System (ADS)

    Gumba, Khuta; Belyaeva, Svetlana

    2017-10-01

    The providing of sustainable development is impossible without activating the innovative activity of backbone economical sectors, in particular of transport construction. The system of self-regulation of activities is a specific feature of the transport industry development. The authors carried out the correlation analysis of innovative activity of construction enterprises, which proved the necessity of improving the normative and technical documents. The authors proposed and calculated the index of the legislation stability in the industry. The article suggests recommendations on the activation of innovative development in construction industry basing on the results of the modeling.

  4. Demonstration of relaxed static stability on a commercial transport

    NASA Technical Reports Server (NTRS)

    Rising, J. J.; Davis, W. J.; Willey, C. S.; Cokeley, R. C.

    1984-01-01

    Increasing jet aircraft fuel costs from 25 percent to nearly 60 percent of the aircraft direct operating costs have led to a heavy emphasis on the development of transport aircraft with significantly improved aerodynamic performance. The application of the concept of relaxed static stability (RSS) and the utilization of an active control stability augmentation system make it possible to design an aircraft with reduced aerodynamic trim drag due to a farther-aft cg balance. Reduced aerodynamic parasite drag and lower structural weight due to a smaller horizontal tail surface can also be obtained. The application of RSS has been studied under a NASA-sponsored program to determine ways of improving the energy efficiency in current and future transport aircraft. Attention is given to a near-term pitch active control system, an advanced pitch active control system, and an operational overview.

  5. Effect of zolpidem on human cytochrome P450 activity, and on transport mediated by P-glycoprotein.

    PubMed

    von Moltke, Lisa L; Weemhoff, James L; Perloff, Michael D; Hesse, Leah M; Harmatz, Jerold S; Roth-Schechter, Barbara F; Greenblatt, David J

    2002-12-01

    The influence of high concentrations of zolpidem (100 microM, corresponding to approximately 200 times maximum therapeutic concentrations) on the activity of six human Cytochrome P450 (CYP) enzymes was evaluated in a model system using human liver microsomes. Zolpidem produced negligible or weak inhibition of human CYP1A2, 2B6, 2C9, 2C19, 2D6, and 3A. Transport of rhodamine 123, presumed to be mediated mainly by the energy-dependent efflux transport protein P-glycoprotein, was studied in a cell culture system using a human intestinal cell line. High concentrations of zolpidem (100 microM), exceeding the usual therapeutic range by more than 100-fold, produced only modest impairment of rhodamine 123 transport. The findings indicate that zolpidem is very unlikely to cause clinical drug interactions attributable to impairment of CYP activity or P-gp mediated transport. Copyright 2002 John Wiley & Sons, Ltd.

  6. Generic Transport Mechanisms for Molecular Traffic in Cellular Protrusions

    NASA Astrophysics Data System (ADS)

    Graf, Isabella R.; Frey, Erwin

    2017-03-01

    Transport of molecular motors along protein filaments in a half-closed geometry is a common feature of biologically relevant processes in cellular protrusions. Using a lattice-gas model we study how the interplay between active and diffusive transport and mass conservation leads to localized domain walls and tip localization of the motors. We identify a mechanism for task sharing between the active motors (maintaining a gradient) and the diffusive motion (transport to the tip), which ensures that energy consumption is low and motor exchange mostly happens at the tip. These features are attributed to strong nearest-neighbor correlations that lead to a strong reduction of active currents, which we calculate analytically using an exact moment identity, and might prove useful for the understanding of correlations and active transport also in more elaborate systems.

  7. A two-component response regulator, gltR, is required for glucose transport activity in Pseudomonas aeruginosa PAO1.

    PubMed Central

    Sage, A E; Proctor, W D; Phibbs, P V

    1996-01-01

    A 729-bp open reading frame (gltR) was identified in Pseudomonas aeruginosa PAO1 that encodes a product homologous to the two-component response regulator family of proteins. Disruption of gltR caused loss of glucose transport activity. Restoration of gltR resulted in wild-type levels of glucose transport. These findings indicate that gltR is required for expression of the glucose transport system in P. aeruginosa. PMID:8830708

  8. Aloe vera enhances the innate immune response of pacu (Piaractus mesopotamicus) after transport stress and combined heat killed Aeromonas hydrophila infection.

    PubMed

    Zanuzzo, Fábio S; Sabioni, Rafael E; Montoya, Luz Natalia F; Favero, Gisele; Urbinati, Elisabeth C

    2017-06-01

    In this study, pacu (Piaractus mesopotamicus) were fed with diets containing Aloe vera for 10 days prior to transport stress and infection with heat killed Aeromonas hydrophila. A. vera is popular around the world due to its medicinal properties, including immunostimulatory effects which was observed in this study. The results show that transport causes immunosuppression, an effect that was prevented by A. vera. Specifically, A. vera prevented reductions of both leukocyte respiratory burst and hemolytic activity of complement system caused by transport. Further, fish fed with A. vera also showed significantly higher leukocyte respiratory burst, serum lysozyme concentrations and activity of complement system 24 h after bacterial infection. Additionally, we observed that A. vera may modulate the innate response through activation of complement system during bacterial immune stimulation. In summary, A. vera extract enhanced innate immune parameters and consequently the ability of fish to cope with pathogens following transport stress. These findings show that A. vera has promise for use in aquaculture and add further evidence that medicinal herbs added to fish feed assist to prevent disease outbreaks. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. A Functional-Phylogenetic Classification System for Transmembrane Solute Transporters

    PubMed Central

    Saier, Milton H.

    2000-01-01

    A comprehensive classification system for transmembrane molecular transporters has been developed and recently approved by the transport panel of the nomenclature committee of the International Union of Biochemistry and Molecular Biology. This system is based on (i) transporter class and subclass (mode of transport and energy coupling mechanism), (ii) protein phylogenetic family and subfamily, and (iii) substrate specificity. Almost all of the more than 250 identified families of transporters include members that function exclusively in transport. Channels (115 families), secondary active transporters (uniporters, symporters, and antiporters) (78 families), primary active transporters (23 families), group translocators (6 families), and transport proteins of ill-defined function or of unknown mechanism (51 families) constitute distinct categories. Transport mode and energy coupling prove to be relatively immutable characteristics and therefore provide primary bases for classification. Phylogenetic grouping reflects structure, function, mechanism, and often substrate specificity and therefore provides a reliable secondary basis for classification. Substrate specificity and polarity of transport prove to be more readily altered during evolutionary history and therefore provide a tertiary basis for classification. With very few exceptions, a phylogenetic family of transporters includes members that function by a single transport mode and energy coupling mechanism, although a variety of substrates may be transported, sometimes with either inwardly or outwardly directed polarity. In this review, I provide cross-referencing of well-characterized constituent transporters according to (i) transport mode, (ii) energy coupling mechanism, (iii) phylogenetic grouping, and (iv) substrates transported. The structural features and distribution of recognized family members throughout the living world are also evaluated. The tabulations should facilitate familial and functional assignments of newly sequenced transport proteins that will result from future genome sequencing projects. PMID:10839820

  10. Improving transportation systems management and operations (TSM&O), capability maturity model workshop white paper : business processes.

    DOT National Transportation Integrated Search

    2015-04-01

    Research done through the Second Strategic Highway Research Program (SHRP 2) determined that agencies with the most effective transportation systems management and operations (TSM&O) activities were differentiated not by budgets or technical skills a...

  11. Improving transportation systems management and operations (TSM&O), capability maturity model workshop white paper : collaboration.

    DOT National Transportation Integrated Search

    2015-04-01

    Research done through the Second Strategic Highway Research Program (SHRP 2) determined that agencies with the most effective transportation systems management and operations (TSM&O) activities were differentiated not by budgets or technical skills a...

  12. Improving transportation systems management and operations (TSM&O), capability maturity model workshop white paper : culture.

    DOT National Transportation Integrated Search

    2015-04-01

    Research done through the Second Strategic Highway Research Program (SHRP 2) determined that agencies with the most effective transportation systems management and operations (TSM&O) activities were differentiated not by budgets or technical skills a...

  13. Improving transportation systems management and operations (TSM&O), capability maturity model workshop white paper : performance measurement.

    DOT National Transportation Integrated Search

    2015-04-01

    Research done through the Second Strategic Highway Research Program (SHRP 2) determined that agencies with the most effective transportation systems management and operations (TSM&O) activities were differentiated not by budgets or technical skills a...

  14. Transport of beta-casein-derived peptides by the oligopeptide transport system is a crucial step in the proteolytic pathway of Lactococcus lactis.

    PubMed

    Kunji, E R; Hagting, A; De Vries, C J; Juillard, V; Haandrikman, A J; Poolman, B; Konings, W N

    1995-01-27

    In the proteolytic pathway of Lactococcus lactis, milk proteins (caseins) are hydrolyzed extracellularly to oligopeptides by the proteinase (PrtP). The fate of these peptides, i.e. extracellular hydrolysis followed by amino acid uptake or transport followed by intracellular hydrolysis, has been addressed. Mutants have been constructed that lack a functional di-tripeptide transport system (DtpT) and/or oligopeptide transport system (Opp) but do express the P1-type proteinase (specific for hydrolysis of beta- and to a lesser extent kappa-casein). The wild type strain and the DtpT- mutant accumulate all beta-casein-derived amino acids in the presence of beta-casein as protein substrate and glucose as a source of metabolic energy. The amino acids are not accumulated significantly inside the cells by the Opp- and DtpT- Opp- mutants. When cells are incubated with a mixture of amino acids mimicking the composition of beta-casein, the amino acids are taken up to the same extent in all four strains. Analysis of the extracellular peptide fraction, formed by the action of PrtP on beta-casein, indicates that distinct peptides disappear only when the cells express an active Opp system. These and other experiments indicate that (i) oligopeptide transport is essential for the accumulation of all beta-casein-derived amino acids, (ii) the activity of the Opp system is sufficiently high to support high growth rates on beta-casein provided leucine and histidine are present as free amino acids, and (iii) extracellular peptidase activity is not present in L. lactis.

  15. 77 FR 70792 - Privacy Act of 1974; Retirement of Department of Homeland Security Transportation Security...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-27

    ... from its inventory of record systems. TSA will rely upon DHS/ALL-017 General Legal Records (November 23, 2011, 76 FR 72428) to cover its legal activities. Eliminating the system of records notice DHS/TSA-009... Department of Homeland Security Transportation Security Administration System of Records AGENCY: Privacy...

  16. Collaborative Approaches in Developing Environmental and Safety Management Systems for Commercial Space Transportation

    NASA Technical Reports Server (NTRS)

    Zee, Stacey; Murray, D.

    2009-01-01

    The Federal Aviation Administration (FAA), Office of Commercial Space Transportation (AST) licenses and permits U.S. commercial space launch and reentry activities, and licenses the operation of non-federal launch and reentry sites. ASTs mission is to ensure the protection of the public, property, and the national security and foreign policy interests of the United States during commercial space transportation activities and to encourage, facilitate, and promote U.S. commercial space transportation. AST faces unique challenges of ensuring the protection of public health and safety while facilitating and promoting U.S. commercial space transportation. AST has developed an Environmental Management System (EMS) and a Safety Management System (SMS) to help meet its mission. Although the EMS and SMS were developed independently, the systems share similar elements. Both systems follow a Plan-Do-Act-Check model in identifying potential environmental aspects or public safety hazards, assessing significance in terms of severity and likelihood of occurrence, developing approaches to reduce risk, and verifying that the risk is reduced. This paper will describe the similarities between ASTs EMS and SMS elements and how AST is building a collaborative approach in environmental and safety management to reduce impacts to the environment and risks to the public.

  17. Effects on transport of rapidly penetrating, competing substrates: activation and inhibition of the choline carrier in erythrocytes by imidazole.

    PubMed

    Devés, R; Krupka, R M

    1987-01-01

    The properties of the choline transport system are fundamentally altered in saline solution containing 5 mM imidazole buffer instead of 5 mM phosphate: (i) The system no longer exhibits accelerated exchange. (ii) Choline in the external compartment fails to increase the rate of inactivation of the carrier by N-ethylmaleimide. (iii) Depending on the relative concentrations of choline and imidazole, transport may be activated or inhibited. The maximum rates are increased more than fivefold by imidazole, but at moderate substrate concentrations activation is observed with low concentrations of imidazole and inhibition with high concentrations. (iv) The imidazole effect is asymmetric, there being a greater tendency to activate exit than entry. All this behavior is predicted by the carrier model if imidazole is a substrate of the choline carrier having a high maximum transport rate but a relatively low affinity, and if imidazole rapidly enters the cell by simple diffusion, so that it can add to carrier sites on both sides of the membrane. Addition at the cis side inhibits, and at the trans side activates. According to the carrier model, asymmetry is a necessary consequence of the potassium ion gradient in red cells, potassium ion being another substrate of the choline system.

  18. Ratchet Effects in Active Matter Systems

    NASA Astrophysics Data System (ADS)

    Reichhardt, C. J. Olson; Reichhardt, C.

    2017-03-01

    Ratchet effects can arise for single or collectively interacting Brownian particles on an asymmetric substrate when a net dc transport is produced by an externally applied ac driving force or by periodically flashing the substrate. Recently, a new class of active ratchet systems that do not require the application of external driving has been realized through the use of active matter; they are self-propelled units that can be biological or nonbiological in nature. When active materials such as swimming bacteria interact with an asymmetric substrate, a net dc directed motion can arise even without external driving, opening a wealth of possibilities such as sorting, cargo transport, or micromachine construction. We review the current status of active matter ratchets for swimming bacteria, cells, active colloids, and swarming models, focusing on the role of particle-substrate interactions. We describe ratchet reversals produced by collective effects and the use of active ratchets to transport passive particles. We discuss future directions including deformable substrates or particles, the role of different swimming modes, varied particle-particle interactions, and nondissipative effects.

  19. Brefeldin A Inhibits Cell-Free, De Novo Synthesis of Poliovirus

    PubMed Central

    Cuconati, Andrea; Molla, Akhteruzzaman; Wimmer, Eckard

    1998-01-01

    Brefeldin A (BFA), an inhibitor of intracellular vesicle-dependent secretory transport, is a potent inhibitor of poliovirus RNA replication in infected cells. We have determined that the unknown mechanism of BFA inhibition of replication is reproduced in the cell-free poliovirus translation, replication, and encapsidation system. Furthermore, we provide evidence suggesting that the cellular mechanism targeted by BFA, the GTP-dependent synthesis of secretory transport vesicles, may be involved in viral RNA replication in the system via a soluble cellular GTP-binding and -hydrolyzing activity. This activity is related to the ARF (ADP-ribosylation factor) family of GTP-binding proteins. ARFs are required for the formation of several classes of secretory vesicles, and some family members are indirectly inactivated by BFA. Peptides that function as competitive inhibitors of ARF activity in cell-free transport systems also inhibit poliovirus RNA replication, and this inhibitory effect can be countered by the addition of exogenous ARF. We suggest that BFA inhibition of replication is diagnostic of a requirement for ARF activity in the cell-free system. PMID:9658088

  20. Modular System to Enable Extravehicular Activity

    NASA Technical Reports Server (NTRS)

    Sargusingh, Miriam J.

    2011-01-01

    The ability to perform extravehicular activity (EVA), both human and robotic, has been identified as a key component to space missions to support such operations as assembly and maintenance of space system (e.g. construction and maintenance of the International Space Station), and unscheduled activities to repair an element of the transportation and habitation systems that can only be accessed externally and via unpressurized areas. In order to make human transportation beyond lower earth orbit (BLEO) practical, efficiencies must be incorporated into the integrated transportation systems to reduce system mass and operational complexity. Affordability is also a key aspect to be considered in space system development; this could be achieved through commonality, modularity and component reuse. Another key aspect identified for the EVA system was the ability to produce flight worthy hardware quickly to support early missions and near Earth technology demonstrations. This paper details a conceptual architecture for a modular extravehicular activity system (MEVAS) that would meet these stated needs for EVA capability that is affordable, and that could be produced relatively quickly. Operational concepts were developed to elaborate on the defined needs and define the key capabilities, operational and design constraints, and general timelines. The operational concept lead to a high level design concept for a module that interfaces with various space transportation elements and contains the hardware and systems required to support human and telerobotic EVA; the module would not be self-propelled and would rely on an interfacing element for consumable resources. The conceptual architecture was then compared to EVA Systems used in the Shuttle Orbiter, on the International Space Station to develop high level design concepts that incorporate opportunities for cost savings through hardware reuse, and quick production through the use of existing technologies and hardware designs. An upgrade option was included to make use of the developing suitport technologies.

  1. Earth Observing System (EOS) Communication (Ecom) Modeling, Analysis, and Testbed (EMAT) activiy

    NASA Technical Reports Server (NTRS)

    Desai, Vishal

    1994-01-01

    This paper describes the Earth Observing System (EOS) Communication (Ecom) Modeling, Analysis, and Testbed (EMAT) activity performed by Code 540 in support of the Ecom project. Ecom is the ground-to-ground data transport system for operational EOS traffic. The National Aeronautic and Space Administration (NASA) Communications (Nascom) Division, Code 540, is responsible for implementing Ecom. Ecom interfaces with various systems to transport EOS forward link commands, return link telemetry, and science payload data. To understand the complexities surrounding the design and implementation of Ecom, it is necessary that sufficient testbedding, modeling, and analysis be conducted prior to the design phase. These activities, when grouped, are referred to as the EMAT activity. This paper describes work accomplished to date in each of the three major EMAT activities: modeling, analysis, and testbedding.

  2. The Space Transportation System. [Space Shuttle-Spacelab-Space Tug system

    NASA Technical Reports Server (NTRS)

    Donlan, C. J.; Brazill, E. J.

    1976-01-01

    The Space Transportation System, consisting of the Space Shuttle, Spacelab, and the Space Tug, is discussed from the viewpoint of reductions in the cost of space operations. Each of the three vehicles is described along with its mission capabilities, and the time table for system development activities is outlined. Basic attributes of the Space Transportation System are reviewed, all operational modes are considered, and the total cost picture of the system is examined from the standpoint of a mission economic analysis. It is concluded that as the features of the Space Transportation System, especially the Shuttle and the Tug, are put to more efficient use during the maturing-operation phase, the total cost of conducting space missions should be about half of what it would be if any other system were employed.

  3. Protecting Surface Transportation Systems and Patrons from Terrorist Activities

    DOT National Transportation Integrated Search

    1997-11-01

    This report documents the first phase of a continuing research effort carried out by the Norman Y. Mineta International Institute for Surface Transportation Policy Studies (IISTPS) on behalf of the U.S. Department of Transportation. It comprises a ch...

  4. 49 CFR 234.109 - Recordkeeping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY AND STATE ACTION PLANS Response to Reports... retain for at least one year (from the latest date of railroad activity in response to a credible report...

  5. 49 CFR 234.109 - Recordkeeping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GRADE CROSSING SIGNAL SYSTEM SAFETY AND STATE ACTION PLANS Response to Reports... retain for at least one year (from the latest date of railroad activity in response to a credible report...

  6. The aircraft energy efficiency active controls technology program

    NASA Technical Reports Server (NTRS)

    Hood, R. V., Jr.

    1977-01-01

    Broad outlines of the NASA Aircraft Energy Efficiency Program for expediting the application of active controls technology to civil transport aircraft are presented. Advances in propulsion and airframe technology to cut down on fuel consumption and fuel costs, a program for an energy-efficient transport, and integrated analysis and design technology in aerodynamics, structures, and active controls are envisaged. Fault-tolerant computer systems and fault-tolerant flight control system architectures are under study. Contracts with leading manufacturers for research and development work on wing-tip extensions and winglets for the B-747, a wing load alleviation system, elastic mode suppression, maneuver-load control, and gust alleviation are mentioned.

  7. Orally active-targeted drug delivery systems for proteins and peptides.

    PubMed

    Li, Xiuying; Yu, Miaorong; Fan, Weiwei; Gan, Yong; Hovgaard, Lars; Yang, Mingshi

    2014-09-01

    In the past decade, extensive efforts have been devoted to designing 'active targeted' drug delivery systems (ATDDS) to improve oral absorption of proteins and peptides. Such ATDDS enhance cellular internalization and permeability of proteins and peptides via molecular recognition processes such as ligand-receptor or antigen-antibody interaction, and thus enhance drug absorption. This review focuses on recent advances with orally ATDDS, including ligand-protein conjugates, recombinant ligand-protein fusion proteins and ligand-modified carriers. In addition to traditional intestinal active transport systems of substrates and their corresponding receptors, transporters and carriers, new targets such as intercellular adhesion molecule-1 and β-integrin are also discussed. ATDDS can improve oral absorption of proteins and peptides. However, currently, no clinical studies on ATDDS for proteins and peptides are underway, perhaps due to the complexity and limited knowledge of transport mechanisms. Therefore, more research is warranted to optimize ATDDS efficiency.

  8. A common transport system for methionine, L-methionine-DL-sulfoximine (MSX), and phosphinothricin (PPT) in the diazotrophic cyanobacterium Nostoc muscorum.

    PubMed

    Singh, Arvind Kumar; Syiem, Mayashree B; Singh, Rajkumar S; Adhikari, Samrat; Rai, Amar Nath

    2008-05-01

    We present evidence, for the first time, of the occurrence of a transport system common for amino acid methionine, and methionine/glutamate analogues L-methionine-DL-sulfoximine (MSX) and phosphinothricin (PPT) in cyanobacterium Nostoc muscorum. Methionine, which is toxic to cyanobacterium, enhanced its nitrogenase activity at lower concentrations. The cyanobacterium showed a biphasic pattern of methionine uptake activity that was competitively inhibited by the amino acids alanine, isoleucine, leucine, phenylalanine, proline, valine, glutamine, and asparagine. The methionine/glutamate analogue-resistant N. muscorum strains (MSX-R and PPT-R strains) also showed methionine-resistant phenotype accompanied by a drastic decrease in 35S methionine uptake activity. Treatment of protein extracts from these mutant strains with MSX and PPT reduced biosynthetic glutamine synthetase (GS) activity only in vitro and not in vivo. This finding implicated that MSX- and PPT-R phenotypes may have arisen due to a defect in their MSX and PPT transport activity. The simultaneous decrease in methionine uptake activity and in vitro sensitivity toward MSX and PPT of GS protein in MSX- and PPT-R strains indicated that methionine, MSX, and PPT have a common transport system that is shared by other amino acids as well in N. muscorum. Such information can become useful for isolation of methionine-producing cyanobacterial strains.

  9. Improving transportation systems management and operations (TSM&O), capability maturity model workshop white paper : organization and staffing.

    DOT National Transportation Integrated Search

    2015-04-01

    Research done through the Second Strategic Highway Research Program (SHRP 2) determined that agencies with the most effective transportation systems management and operations (TSM&O) activities were differentiated not by budgets or technical skills a...

  10. Orbital transportation in the 1980's and beyond

    NASA Technical Reports Server (NTRS)

    Davis, H. P.

    1975-01-01

    Orbital transportation beyond the low earth orbit operating regime of the Space Shuttle will be required for the 1980's and beyond. The characteristics and first order requirements of the mission arenas are discussed in context with a broad spectrum of future space transportation systems. Several concepts are highlighted and identify the distinctly different requirements imposed by manned vehicles versus unmanned vehicles. Considerable analytic and design activities are necessary prior to selection of orbital transportation systems to be developed after the Interim Upper Stage (IUS).

  11. Hydrogen Research for Spaceport and Space-Based Applications: Hydrogen Production, Storage, and Transport. Part 3

    NASA Technical Reports Server (NTRS)

    Anderson, Tim; Balaban, Canan

    2008-01-01

    The activities presented are a broad based approach to advancing key hydrogen related technologies in areas such as fuel cells, hydrogen production, and distributed sensors for hydrogen-leak detection, laser instrumentation for hydrogen-leak detection, and cryogenic transport and storage. Presented are the results from research projects, education and outreach activities, system and trade studies. The work will aid in advancing the state-of-the-art for several critical technologies related to the implementation of a hydrogen infrastructure. Activities conducted are relevant to a number of propulsion and power systems for terrestrial, aeronautics and aerospace applications. Hydrogen storage and in-space hydrogen transport research focused on developing and verifying design concepts for efficient, safe, lightweight liquid hydrogen cryogenic storage systems. Research into hydrogen production had a specific goal of further advancing proton conducting membrane technology in the laboratory at a larger scale. System and process trade studies evaluated the proton conducting membrane technology, specifically, scale-up issues.

  12. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project. ACT/Control/Guidance System study, volume 1

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The active control technology (ACT) control/guidance system task of the integrated application of active controls (IAAC) technology project within the NASA energy efficient transport program was documented. The air traffic environment of navigation and air traffic control systems and procedures were extrapolated. An approach to listing flight functions which will be performed by systems and crew of an ACT configured airplane of the 1990s, and a determination of function criticalities to safety of flight, are the basis of candidate integrated ACT/Control/Guidance System architecture. The system mechanizes five active control functions: pitch augmented stability, angle of attack limiting, lateral/directional augmented stability, gust load alleviation, and maneuver load control. The scope and requirements of a program for simulating the integrated ACT avionics and flight deck system, with pilot in the loop, are defined, system and crew interface elements are simulated, and mechanization is recommended. Relationships between system design and crew roles and procedures are evaluated.

  13. Impact of GDP Information Technology in Developing of Regional Central Business (Case 50 Airports IT City Development in Indonesia)

    NASA Astrophysics Data System (ADS)

    Suyono, Joko; Sukoco, Agus; Ikhsan Setiawan, M.; Suhermin; Rahim, Robbi

    2017-12-01

    Indonesia a great number of populations and demand of air transportation services keep increasing by the year in line with the increasing of population and welfare its people. Need for telematics solutions to support goods transport and distribution in cities is mainly due to the complexity of the processes taking place in urban transport systems and the importance of the optimisation of transport operations via ensuring adequate availability of linear and point infrastructure, while reducing the adverse impacts of the transport system on the environment. Efficient infrastructure supports economic growth, improves quality of life, and it is important for national security. Impact of GDP Information Technology in developing of Regional Central Business especially SME Business, are very large correlations and very significant supported by Passenger Arrival and Departure, Baggage Loaded and Unloaded, Cargo Loaded and Unloaded, Separated regional asset, Grant, Capital Expenditure, Investment of Regional Gov., GDP Agriculture-Forestry-Fishing, GDP Manufacturing, GDP Electricity-Gas, GDP Water supply- Sewerage-Waste Management-Remediation Activities, GDP Financial-Insurance Activities, GDP Business Activities, GDP Public Administration and Defense-Compulsory Social Security, GDP Education and GDP Other Services Activities

  14. The transport forecast - an important stage of transport management

    NASA Astrophysics Data System (ADS)

    Dragu, Vasile; Dinu, Oana; Oprea, Cristina; Alina Roman, Eugenia

    2017-10-01

    The transport system is a powerful system with varying loads in operation coming from changes in freight and passenger traffic in different time periods. The variations are due to the specific conditions of organization and development of socio-economic activities. The causes of varying loads can be included in three groups: economic, technical and organizational. The assessing of transport demand variability leads to proper forecast and development of the transport system, knowing that the market price is determined on equilibrium between supply and demand. The reduction of transport demand variability through different technical solutions, organizational, administrative, legislative leads to an increase in the efficiency and effectiveness of transport. The paper presents a new way of assessing the future needs of transport through dynamic series. Both researchers and practitioners in transport planning can benefit from the research results. This paper aims to analyze in an original approach how a good transport forecast can lead to a better management in transport, with significant effects on transport demand full meeting in quality terms. The case study shows how dynamic series of statistics can be used to identify the size of future demand addressed to the transport system.

  15. Stochastic dynamics of coupled active particles in an overdamped limit

    NASA Astrophysics Data System (ADS)

    Ann, Minjung; Lee, Kong-Ju-Bock; Park, Pyeong Jun

    2015-10-01

    We introduce a model for Brownian dynamics of coupled active particles in an overdamped limit. Our system consists of several identical active particles and one passive particle. Each active particle is elastically coupled to the passive particle and there is no direct coupling among the active particles. We investigate the dynamics of the system with respect to the number of active particles, viscous friction, and coupling between the active and passive particles. For this purpose, we consider an intracellular transport process as an application of our model and perform a Brownian dynamics simulation using realistic parameters for processive molecular motors such as kinesin-1. We determine an adequate energy conversion function for molecular motors and study the dynamics of intracellular transport by multiple motors. The results show that the average velocity of the coupled system is not affected by the number of active motors and that the stall force increases linearly as the number of motors increases. Our results are consistent with well-known experimental observations. We also examine the effects of coupling between the motors and the cargo, as well as of the spatial distribution of the motors around the cargo. Our model might provide a physical explanation of the cooperation among active motors in the cellular transport processes.

  16. Conference Proceedings for the Advanced Multimodal Transportation Weather Services Partnership Initiatives

    DOT National Transportation Integrated Search

    1999-01-01

    A symposium was held at the Volpe National Transportation Systems Center on September 28, 1998 to continue an active dialogue on issues related to the use of weather informaiton to support transportation decision making, safety, and efficiency. The o...

  17. Indigenous Māori perspectives on urban transport patterns linked to health and wellbeing.

    PubMed

    Raerino Ngāti Awa Te Arawa, K; Macmillan, Alex K; Jones Ngāti Kahungunu, Rhys G

    2013-09-01

    There is a growing body of research linking urban transport systems to inequities in health. However, there is a lack of research providing evidence of the effect of transport systems on indigenous family wellbeing. We examined the connections between urban transport and the health and wellbeing of Māori, the indigenous people of New Zealand. We provide an indigenous exploration of current urban transport systems, with a particular focus on the impacts of car dependence and the need for culturally relevant travel. We interviewed nineteen Māori participants utilising qualitative research techniques underpinned by an indigenous research methodology (Kaupapa Māori). The data highlighted the importance of accessing cultural activities and sites relevant to 'being Māori', and issues with affordability and safety of public transport. Understanding the relationship between indigenous wellbeing and transport systems that goes further than limited discourses of inequity is essential to improving transport for indigenous wellbeing. Providing an indigenous voice in transport decision-making will make it more likely that indigenous health and wellbeing is prioritised in transport planning. Copyright © 2013. Published by Elsevier Ltd.

  18. 75 FR 11621 - Agency Information Collection Activities: Notice of Request for Extension of Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-11

    ... Awards (TPEA) Program is a biennial awards program developed by the FHWA and the Federal Transit... System Preservation Program Grant Application. Delta Region Transportation Development Program Grant...: Transportation, Community, and System Preservation Program Grant Application: Section 1117 of the Safe...

  19. An Investigation of The Use of Global Positioning System (GPS) Technology and Its Augmentations Within State and Local Transportation Departments

    DOT National Transportation Integrated Search

    2000-07-01

    This report summarizes Global Positioning System (GPS) technology and its augmentation-related activities within State and local transportation agencies. In general, the following items are addressed for each State that participated in this investiga...

  20. Activity-Based Travel Demand Modeling for Metropolitan Areas in Texas: Model Components and Mathematical Formulations

    DOT National Transportation Integrated Search

    2001-09-01

    The goal of this project is to comprehensively model the activity-travel patterns of workers as well as non-workers in a household. The activity-travel system will take as input various land use, socio-demographic, activity system, and transportation...

  1. NH4+ transport system of a psychrophilic marine bacterium, Vibrio sp. strain ABE-1.

    PubMed

    Chou, M; Matsunaga, T; Takada, Y; Fukunaga, N

    1999-05-01

    NH4(+) transport system of a psychrophilic marine bacterium Vibrio sp. strain ABE-1 (Vibrio ABE-1) was examined by measuring the uptake of [14C]methylammonium ion (14CH3NH3+) into the intact cells. 14CH3NH3+ uptake was detected in cells grown in medium containing glutamate as the sole nitrogen source, but not in those grown in medium containing NH4Cl instead of glutamate. Vibrio ABE-1 did not utilize CH3NH3+ as a carbon or nitrogen source. NH4Cl and nonradiolabeled CH3NH3+ completely inhibited 14CH3NH3+ uptake. These results indicate that 14CH3NH3+ uptake in this bacterium is mediated via an NH4+ transport system and not by a specific carrier for CH3NH3+. The respiratory substrate succinate was required to drive 14CH3NH3+ uptake and the uptake was completely inhibited by KCN, indicating that the uptake was energy dependent. The electrochemical potentials of H+ and/or Na+ across membranes were suggested to be the driving forces for the transport system because the ionophores carbonylcyanide m-chlorophenylhydrazone and monensin strongly inhibited uptake activities at pH 6.5 and 8.5, respectively. Furthermore, KCl activated 14CH3NH3+ uptake. The 14CH3NH3+ uptake activity of Vibrio ABE-1 was markedly high at temperatures between 0 degrees and 15 degrees C, and the apparent Km value for CH3NH3+ of the uptake did not change significantly over the temperature range from 0 degrees to 25 degrees C. Thus, the NH4+ transport system of this bacterium was highly active at low temperatures.

  2. The plasma membrane of Saccharomyces cerevisiae: structure, function, and biogenesis.

    PubMed Central

    van der Rest, M E; Kamminga, A H; Nakano, A; Anraku, Y; Poolman, B; Konings, W N

    1995-01-01

    The composition of phospholipids, sphingolipids, and sterols in the plasma membrane has a strong influence on the activity of the proteins associated or embedded in the lipid bilayer. Since most lipid-synthesizing enzymes in Saccharomyces cerevisiae are located in intracellular organelles, an extensive flux of lipids from these organelles to the plasma membrane is required. Although the pathway of protein traffic to the plasma membrane is similar to that of most of the lipids, the bulk flow of lipids is separate from vesicle-mediated protein transport. Recent advances in the analysis of membrane budding and membrane fusion indicate that the mechanisms of protein transport from the endoplasmic reticulum to the Golgi and from the Golgi to plasma membrane are similar. The majority of plasma membrane proteins transport solutes across the membrane. A number of ATP-dependent export systems have been detected that couple the hydrolysis of ATP to transport of molecules out of the cell. The hydrolysis of ATP by the plasma membrane H(+)-ATPase generates a proton motive force which is used to drive secondary transport processes. In S. cerevisiae, many substrates are transported by more than one system. Transport of monosaccharide is catalyzed by uniport systems, while transport of disaccharides, amino acids, and nucleosides is mediated by proton symport systems. Transport activity can be regulated at the level of transcription, e.g., induction and (catabolite) repression, but transport proteins can also be affected posttranslationally by a process termed catabolite inactivation. Catabolite inactivation is triggered by the addition of fermentable sugars, intracellular acidification, stress conditions, and/or nitrogen starvation. Phosphorylation and/or ubiquitination of the transport proteins has been proposed as an initial step in the controlled inactivation and degradation of the target enzyme. The use of artificial membranes, like secretory vesicles and plasma membranes fused with proteoliposomes, as model systems for studies on the mechanism and regulation of transport is evaluated. PMID:7603412

  3. Ergonomics, safety, and resilience in the helicopter offshore transportation system of Campos Basin.

    PubMed

    Gomes, José Orlando; Huber, Gilbert J; Borges, Marcos R S; de Carvalho, Paulo Victor R

    2015-01-01

    Air transportation of personnel to offshore oil platforms is one of the major hazards of this kind of endeavor. Pilot performance is a key factor in the safety of the transportation system. This study seeks to identify the ergonomic factors present in pilots' activities that may in some way compromise or enhance their performance, the constraints and affordances which they are subject to; and where possible to link these to their associated risk factors. Methodology adopted in this project studies work in its context. It is a merging of Activity Analysis (Guerin et al. 2001) of European tradition with Cognitive Task Analysis (CTA - www.ctaresource.com) articulated with the recent approaches to cognitive systems engineering developed by Professors David Woods and Erik Hollnagel. Fifty-five hours of field interviews provided the input for analysis. Sixteen ergonomic constraints were identified, some cognitive, some physical, all considered relevant by the research subjects and expert advisers. Although the safety record of the personnel transportation system studied is considered acceptable, there is low hanging fruit to be picked which can help improve the system's safety.

  4. Sodium-coupled neutral amino acid (System N/A) transporters of the SLC38 gene family.

    PubMed

    Mackenzie, Bryan; Erickson, Jeffrey D

    2004-02-01

    The sodium-coupled neutral amino acid transporters (SNAT) of the SLC38 gene family resemble the classically-described System A and System N transport activities in terms of their functional properties and patterns of regulation. Transport of small, aliphatic amino acids by System A subtypes (SNAT1, SNAT2, and SNAT4) is rheogenic and pH sensitive. The System N subtypes SNAT3 and SNAT5 also countertransport H(+), which may be key to their operation in reverse, and have narrower substrate profiles than do the System A subtypes. Glutamine emerges as a favored substrate throughout the family, except for SNAT4. The SLC38 transporters undoubtedly play many physiological roles including the transfer of glutamine from astrocyte to neuron in the CNS, ammonia detoxification and gluconeogenesis in the liver, and the renal response to acidosis. Probing their regulation has revealed additional roles, and recent work has considered SLC38 transporters as therapeutic targets in neoplasia.

  5. Emergency EDAPTS retainer support.

    DOT National Transportation Integrated Search

    2007-06-01

    The Efficient Deployment of Advanced Transportation Systems (EDAPTS) Smart Transit System Project : required various quick-response deployment support activities over the 26-month period from April 18, 2005 : to June 30, 2007. These activities requir...

  6. Frequency and concentration windows for the electric activation of a membrane active transport system.

    PubMed Central

    Markin, V. S.; Tsong, T. Y.

    1991-01-01

    Previous work has shown that a simple four-state membrane transport system can interact with an oscillating electric field to become an active transport system if there is charge translocation associated with conformational changes of the transporter and if affinities of the transporter for the ligand on the two sides of membrane are different. The relationship between the transport flux and both the frequency of the applied field and the concentration of ligand have been examined based on the following assumptions: the rate of the electroconformational change of the transporter is much greater than that of the ligand association/dissociation reaction, and the oscillating electric field has a large amplitude. It was found that the transport flux depends strongly on the frequency of the field and on the concentration of the ligand and it displays a window of broad bandwidth both on the frequency and the concentration axes. The maximum concentration gradient, or the static head, which can be supported by this mechanism is shown to be constant for field frequencies smaller than the rate of the electroconformational change. The static head value diminishes completely when the field frequency exceeds the rate of the conformational change. The presence of an optimal field frequency has been shown experimentally in several membrane enzyme systems. The theory was applied to the description of Rb and Na pumping in human erythrocytes stimulated by an AC field. The prediction of a window for a ligand concentration and the static head value may be tested experimentally. In addition, the rate constants and the equilibrium constants of the four state model can be determined by measuring positions of windows, fluxes, and static head values under different experimental conditions. These results are equally applicable to the oscillation of pressure, membrane tension, substrate concentration, or temperature if these external parameters can induce functionally relevant conformational changes of the transporter. Images FIGURE 8 PMID:1873467

  7. Using GPS, GIS, and Accelerometer Data to Predict Transportation Modes.

    PubMed

    Brondeel, Ruben; Pannier, Bruno; Chaix, Basile

    2015-12-01

    Active transportation is a substantial source of physical activity, which has a positive influence on many health outcomes. A survey of transportation modes for each trip is challenging, time-consuming, and requires substantial financial investments. This study proposes a passive collection method and the prediction of modes at the trip level using random forests. The RECORD GPS study collected real-life trip data from 236 participants over 7 d, including the transportation mode, global positioning system, geographical information systems, and accelerometer data. A prediction model of transportation modes was constructed using the random forests method. Finally, we investigated the performance of models on the basis of a limited number of participants/trips to predict transportation modes for a large number of trips. The full model had a correct prediction rate of 90%. A simpler model of global positioning system explanatory variables combined with geographical information systems variables performed nearly as well. Relatively good predictions could be made using a model based on the 991 trips of the first 30 participants. This study uses real-life data from a large sample set to test a method for predicting transportation modes at the trip level, thereby providing a useful complement to time unit-level prediction methods. By enabling predictions on the basis of a limited number of observations, this method may decrease the workload for participants/researchers and provide relevant trip-level data to investigate relations between transportation and health.

  8. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project. ACT/Control/Guidance System study. Volume 2: Appendices

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The integrated application of active controls (IAAC) technology to an advanced subsonic transport is reported. Supplementary technical data on the following topics are included: (1) 1990's avionics technology assessment; (2) function criticality assessment; (3) flight deck system for total control and functional features list; (4) criticality and reliability assessment of units; (5) crew procedural function task analysis; and (6) recommendations for simulation mechanization.

  9. Glutathione affects the transport activity of Rhizobium leguminosarum 3841 and is essential for efficient nodulation.

    PubMed

    Cheng, Guojun; Karunakaran, Ramakrishnan; East, Alison K; Munoz-Azcarate, Olaya; Poole, Philip S

    2017-04-01

    As glutathione (GSH) plays an essential role in growth and symbiotic capacity of rhizobia, a glutathione synthetase (gshB) mutant of Rhizobium leguminosarum biovar viciae 3841 (Rlv3841) was characterised. It fails to efficiently utilise various compounds as a sole carbon source, including glucose, succinate, glutamine and histidine, and shows 60%-69% reduction in uptake rates of glucose, succinate and the non-metabolisable substrate α-amino isobutyric acid. The defect in glucose uptake can be overcome by addition of exogenous GSH, indicating GSH, but not its bacterial synthesis, is required for efficient transport. GSH is not involved in the regulation of the activity of Rlv3841's transporters via the global regulator of transport, PtsNTR. Although lack of GSH reduces transcription of the branched amino acid transporter, this was not the case for all uptake transport systems, for example, the amino acid permease. This suggests GSH alters activity and/or assembly of transport systems by an unknown mechanism. In interaction with plants, the gshB mutant is not only severely impaired in rhizosphere colonisation, but also shows a 50% reduction in dry weight of plants and nitrogen-fixation ability. This reveals that changes in GSH metabolism affect the bacterial-plant interactions required for symbiosis. © FEMS 2017.

  10. Structure-activity relationships for xenobiotic transport substrates and inhibitory ligands of P-glycoprotein.

    PubMed Central

    Bain, L J; McLachlan, J B; LeBlanc, G A

    1997-01-01

    The multixenobiotic resistance phenotype is characterized by the reduced accumulation of xenobiotics by cells or organisms due to increased efflux of the compounds by P-glycoprotein (P-gp) or related transporters. An extensive xenobiotic database, consisting primarily of pesticides, was utilized in this study to identify molecular characteristics that render a xenobiotic susceptible to transport by or inhibition of P-gp. Transport substrates were differentiated by several molecular size/shape parameters, lipophilicity, and hydrogen bonding potential. Electrostatic features differentiated inhibitory ligands from compounds not catagorized as transport substrates and that did no interact with P-gp. A two-tiered system was developed using the derived structure-activity relationships to identify P-gp transport substrates and inhibitory ligands. Prediction accuracy of the approach was 82%. We then validated the system using six additional pesticides of which tow were predicted to be P-gp inhibitors and four were predicted to be noninteractors, based upon the structure-activity analyses. Experimental determinations using cells transfected with the human MDR1 gene demonstrated that five of the six pesticides were properly catagorized by the structure-activity analyses (83% accuracy). Finally, structure-activity analyses revealed that among P-gp inhibitors, relative inhibitory potency can be predicted based upon the surface area or volume of the compound. These results demonstrate that P-gp transport substrates and inhibitory ligands can be distinguished using molecular characteristics. Molecular characteristics of transport substrates suggest that P-gp may function in the elimination of hydroxylated metabolites of xenobiotics. Images Figure 1. A Figure 1. B Figure 1. C Figure 1. D Figure 1. E Figure 1. F Figure 1. G Figure 1. H Figure 2. Figure 2. Figure 2. Figure 2. Figure 2. Figure 2. Figure 3. A Figure 3. B PMID:9347896

  11. Transportation analyses for the lunar-Mars initiative

    NASA Technical Reports Server (NTRS)

    Woodcock, Gordon R.; Buddington, Patricia A.

    1991-01-01

    This paper focuses on certain results of an ongoing NASA-sponsored study by Boeing, including (1) a series of representative space exploration scenarios; (2) the levels of effort required to accomplish each; and (3) a range of candidate transportation system as partial implementations of the scenarios. This effort predated release of the Synthesis report; the three levels of activity described are not responses to the Synthesis architectures. These three levels (minimum, median and ambitious), do envelope the range of scope described in the four Synthesis architecture models. The level of analysis detail was to the current known level of detail of transportation hardware systems and mission scenarios. The study did not include detailed analysis of earth-to-orbit transportation, surface systems, or tracking and communications systems. The influence of earth-to-orbit systems was considered in terms of delivery capacity and cost. Aspects of additional options, such as in situ resource utilization are explored as needed to indicate potential benefits. Results favored cryogenic chemical propulsion for low activity levels and undemanding missions (such as cargo and some lunar missions), nuclear thermal propulsion for median activity levels similar to the Synthesis architectures, and nuclear thermal propulsion with aerobraking or nuclear electric propulsion for high activity levels. Solar electric propulsion was seen as having an important role if the present high unit cost (i.e., dollars per watt) of space photovoltaics could be reduced by a factor of five or more at production rates of megawatts per year.

  12. Biking in fresh air: consideration of exposure to traffic-related air pollution in bicycle route planning.

    DOT National Transportation Integrated Search

    2017-03-01

    Active transportation modes such as walking and biking are key elements of sustainable : transportation systems. In order to promote biking as an alternative form of transportation, a : holistic approach to improving the quality of the biking experie...

  13. Constitutive mRNA expression and protein activity levels of nine ABC efflux transporters in seven permanent cell lines derived from different tissues of rainbow trout (Oncorhynchus mykiss).

    PubMed

    Fischer, Stephan; Loncar, Jovica; Zaja, Roko; Schnell, Sabine; Schirmer, Kristin; Smital, Tvrtko; Luckenbach, Till

    2011-01-25

    Permanent fish cell lines have become common model systems for determining ecotoxicological effects of pollutants. For these cell lines little is known on the cellular active transport mechanisms that control the amount of a compound entering the cell, such as the MXR (multixenobiotic resistance) system mediated by ATP binding cassette (ABC) transport proteins. Therefore, for toxic evaluation of chemicals with those cells information on MXR is important. We here present data on constitutive mRNA expression and protein activity levels of a series of ABC efflux transporters in seven permanent cell lines derived from liver (RTL-W1; R1) and liver hepatoma (RTH-149), gill (RTgill-W1), gonad (RTG-2), gut (RTgutGC) and brain (RTbrain) of rainbow trout (Oncorhynchus mykiss). In addition to known transporters abcb1 (designated here abcb1a), abcb11, abcc1-3, abcc5 and abcg2, we quantified expression levels of a newly identified abcb1 isoform (abcb1b) and abcc4, previously unknown in trout. Quantitative real time PCR (qPCR) indicated that mRNA of the examined ABC transporters was constitutively expressed in all cell lines. Transporter mRNA expression patterns were similar in all cell lines, with expression levels of abcc transporters being 80 to over 1000 fold higher than for abcg2, abcb1a/b and abcb11 (abcc1-5>abcg2>abcb1a/b, 11). Transporter activity in the cell lines was determined by measuring uptake of transporter type specific fluorescent substrates in the presence of activity inhibitors. The combination of the ABCB1 and ABCC transporter substrate calcein-AM with inhibitors cyclosporine A, PSC833 and MK571 resulted in a concentration-dependent fluorescence increase of up to 3-fold, whereas reversin 205 caused a slight, but not concentration-dependent fluorescence increase. Accumulation of the dyes Hoechst 33342 and 2',7'-dichlorodihydrofluorescein diacetate was basically unchanged in the presence of Ko134 and taurocholate, respectively, indicating low Abcg2 and Abcb11 activities, in accordance with low abcg2 and abcb11 transcript levels. Our data indicate that transporter expression and activity patterns in the different trout cell lines are irrespective of the tissue of origin, but are determined by factors of cell cultivation. 2010 Elsevier B.V. All rights reserved.

  14. 77 FR 3557 - Agency Information Collection Activity Under OMB Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-24

    ... financial and operating information from the nation's public transportation systems. Congress created the NTD to be the repository of transit data for the nation to support public transportation service... each system to report the data, including collecting and assembling the data for each mode, filling out...

  15. Space transportation systems within ESA programmes: Current status and perspectives

    NASA Astrophysics Data System (ADS)

    Delahais, Maurice

    1993-03-01

    An overview of the space transportation aspects of the ESA (European Space Agency) programs as they result from history, present status, and decisions taken at the ministerial level conference in Granada, Spain is presented. The new factors taken into consideration for the long term plan proposed in Munich, Germany, the three strategic options for the reorientation of the ESA long term plan, and the essential elements of space transportation in the Granada long term plan in three areas of space activities, scientific, and commercial launches with expendable launch vehicles, manned flight and in-orbit infrastructure, and future transportation systems are outlined. The new ESA long term plan, in the field of space transportation systems, constitutes a reorientation of the initial program contemplated in previous councils at ministerial level. It aims at balancing the new economic situation with the new avenues of cooperation, and the outcome will be a new implementation of the space transportation systems policy.

  16. Estimated United States Transportation Energy Use 2005

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Smith, C A; Simon, A J; Belles, R D

    A flow chart depicting energy flow in the transportation sector of the United States economy in 2005 has been constructed from publicly available data and estimates of national energy use patterns. Approximately 31,000 trillion British Thermal Units (trBTUs) of energy were used throughout the United States in transportation activities. Vehicles used in these activities include automobiles, motorcycles, trucks, buses, airplanes, rail, and ships. The transportation sector is powered primarily by petroleum-derived fuels (gasoline, diesel and jet fuel). Biomass-derived fuels, electricity and natural gas-derived fuels are also used. The flow patterns represent a comprehensive systems view of energy used within themore » transportation sector.« less

  17. Coupling of active motion and advection shapes intracellular cargo transport.

    PubMed

    Khuc Trong, Philipp; Guck, Jochen; Goldstein, Raymond E

    2012-07-13

    Intracellular cargo transport can arise from passive diffusion, active motor-driven transport along cytoskeletal filament networks, and passive advection by fluid flows entrained by such cargo-motor motion. Active and advective transport are thus intrinsically coupled as related, yet different representations of the same underlying network structure. A reaction-advection-diffusion system is used here to show that this coupling affects the transport and localization of a passive tracer in a confined geometry. For sufficiently low diffusion, cargo localization to a target zone is optimized either by low reaction kinetics and decoupling of bound and unbound states, or by a mostly disordered cytoskeletal network with only weak directional bias. These generic results may help to rationalize subtle features of cytoskeletal networks, for example as observed for microtubules in fly oocytes.

  18. Flutter suppression and gust alleviation using active controls

    NASA Technical Reports Server (NTRS)

    Nissim, E.

    1974-01-01

    The effects of active controls on the suppression of flutter and gust alleviation of two different types of subsonic aircraft (the Arava, twin turboprop STOL transport, and the Westwind twin-jet business transport) are investigated. The active controls are introduced in pairs which include, in any chosen wing strip, a leading-edge (LE) control and a trailing-edge (TE) control. Each control surface is allowed to be driven by a combined linear-rotational sensor system, located on the activated strip. The control law, which translates the sensor signals into control surface rotations, is based on the concept of aerodynamic energy. The results indicate the extreme effectiveness of the active systems in controlling flutter. A single system spanning 10% of the wing semispan made the Arava flutter-free, and a similar active system, for the Westwind aircraft, yielded a reduction of 75% in the maximum bending moment of the wing and a reduction of 90% in the acceleration of the cg of the aircraft. Results for simultaneous activation of several LE - TE systems are presented. Further work needed to bring the investigation to completion is also discussed.

  19. Analysis, Modeling, and Simulation (AMS) testbed framework for Dynamic Mobility Applications (DMA) and Active Transportation and Demand Management (ATDM) programs.

    DOT National Transportation Integrated Search

    1997-08-01

    A Regional ITS/CVO Coordination Plan outlines a strategy for the deployment of Intelligent Transportation Systems (ITS)/Commercial Vehicle Operations (CVO) technologies by a group of states with common economic and transportation needs. The Coordinat...

  20. High-Affinity Vanadate Transport System in the Cyanobacterium Anabaena variabilis ATCC 29413

    PubMed Central

    Pratte, Brenda S.; Thiel, Teresa

    2006-01-01

    High-affinity vanadate transport systems have not heretofore been identified in any organism. Anabaena variabilis, which can fix nitrogen by using an alternative V-dependent nitrogenase, transported vanadate well. The concentration of vanadate giving half-maximum V-nitrogenase activity when added to V-starved cells was about 3 × 10−9 M. The genes for an ABC-type vanadate transport system, vupABC, were found in A. variabilis about 5 kb from the major cluster of genes encoding the V-nitrogenase, and like those genes, the vupABC genes were repressed by molybdate; however, unlike the V-nitrogenase genes the vanadate transport genes were expressed in vegetative cells. A vupB mutant failed to grow by using V-nitrogenase unless high levels of vanadate were provided, suggesting that there was also a low-affinity vanadate transport system that functioned in the vupB mutant. The vupABC genes belong to a family of putative metal transport genes that include only one other characterized transport system, the tungstate transport genes of Eubacterium acidaminophilum. Similar genes are not present in the complete genomes of other bacterial strains that have a V-nitrogenase, including Azotobacter vinelandii, Rhodopseudomonas palustris, and Methanosarcina barkeri. PMID:16385036

  1. Microfluidic systems and methods of transport and lysis of cells and analysis of cell lysate

    DOEpatents

    Culbertson, Christopher T.; Jacobson, Stephen C.; McClain, Maxine A.; Ramsey, J. Michael

    2004-08-31

    Microfluidic systems and methods are disclosed which are adapted to transport and lyse cellular components of a test sample for analysis. The disclosed microfluidic systems and methods, which employ an electric field to rupture the cell membrane, cause unusually rapid lysis, thereby minimizing continued cellular activity and resulting in greater accuracy of analysis of cell processes.

  2. Microfluidic systems and methods for transport and lysis of cells and analysis of cell lysate

    DOEpatents

    Culbertson, Christopher T [Oak Ridge, TN; Jacobson, Stephen C [Knoxville, TN; McClain, Maxine A [Knoxville, TN; Ramsey, J Michael [Knoxville, TN

    2008-09-02

    Microfluidic systems and methods are disclosed which are adapted to transport and lyse cellular components of a test sample for analysis. The disclosed microfluidic systems and methods, which employ an electric field to rupture the cell membrane, cause unusually rapid lysis, thereby minimizing continued cellular activity and resulting in greater accuracy of analysis of cell processes.

  3. CTOL Transport Technology, 1978. [conferences

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Technology associated with advanced conventional takeoff and landing transport aircraft is discussed. Topics covered include: advanced aerodynamics and active controls; operations and safety; and advanced systems. Emphasis is placed on increased energy efficiency.

  4. Final report : UF workforce development efforts.

    DOT National Transportation Integrated Search

    2014-06-01

    Workforce development activities aim to attract new entrants into the transportation field : and improve the skills of the existing workforce to effectively address todays transportation : system challenges. The University of Florida Transportatio...

  5. High voltage disconnect systems

    DOT National Transportation Integrated Search

    2008-03-01

    The recent establishment of the National University Transportation Center at MST under the "Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users," expands the research and education activities to include alternative tr...

  6. Advanced control technology and its potential for future transport aircraft

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The topics covered include fly by wire, digital control, control configured vehicles, applications to advanced flight vehicles, advanced propulsion control systems, and active control technology for transport aircraft.

  7. Measuring H(+) Pumping and Membrane Potential Formation in Sealed Membrane Vesicle Systems.

    PubMed

    Wielandt, Alex Green; Palmgren, Michael G; Fuglsang, Anja Thoe; Günther-Pomorski, Thomas; Justesen, Bo Højen

    2016-01-01

    The activity of enzymes involved in active transport of matter across lipid bilayers can conveniently be assayed by measuring their consumption of energy, such as ATP hydrolysis, while it is more challenging to directly measure their transport activities as the transported substrate is not converted into a product and only moves a few nanometers in space. Here, we describe two methods for the measurement of active proton pumping across lipid bilayers and the concomitant formation of a membrane potential, applying the dyes 9-amino-6-chloro-2-methoxyacridine (ACMA) and oxonol VI. The methods are exemplified by assaying transport of the Arabidopsis thaliana plasma membrane H(+)-ATPase (proton pump), which after heterologous expression in Saccharomyces cerevisiae and subsequent purification has been reconstituted in proteoliposomes.

  8. Variations in periplasmic loop interactions determine the pH-dependent activity of the hexameric urea transporter UreI from Helicobacter pylori: a molecular dynamics study.

    PubMed

    Cáceres-Delpiano, Javier; Teneb, Jaime; Mansilla, Rodrigo; García, Apolinaria; Salas-Burgos, Alexis

    2015-06-26

    Helicobacter pylori is an important factor in the development of diseases such as ulcer and gastric cancer. This bacterium uses a periplasmic transporter, UreI, to deliver urea to the intracelullar space, where later it is transformed into ammonia by the cytoplasmic enzyme urease to survive the acidic condition of the human stomach. The UreI transporter presents a pH-dependent activity, where this pH-dependence remains unknown at a structural level. Althought the existance of several protonable residues in the periplasmic loops are related to the pH-dependent activity, we find interesting to have a clear view of the conformational changes involved in this phenomena through a molecular dynamic study. Molecular dynamic simulations of the UreI transporter at three different pH conditions were performed, revealing two main pH-dependent conformations, which we present as the open and close states. We find that salt bridges between the periplasmic loops are crucial interactions that stabilize these conformations. Besides, a cooperative behaviour exists between the six subunits of the system that is necessary to fulfill the activity of this transporter. We found different pH-dependent conformations of the urea transporter UreI from Helicobacter pylori, which are related to salt-bridge interactions in the periplasmic regions. The behaviour of every channel in the system is not independent, given the existance of a cooperative behaviour through the formation of salt-bridges between the subunits of the hexameric system. We believe that our results will be related to the generation of new eradication therapies using this transporter as an attractive target, denoting that the knowledge of the possible pH-dependent conformations adopted for this transporter are important for the development of rational drug design approximations.

  9. Molecular-Flow Properties of RIB Type Vapor-Transport Systems Using a Fast-Valve

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Alton, Gerald D; Bilheux, Hassina Z; Zhang, Y.

    2014-01-01

    The advent of the fast-valve device, described previously, permits measurement of molecular-flow times of chemically active or inactive gaseous species through radioactive ion beam (RIB) target ion source systems, independent of size, geometry and materials of construction. Thus, decay losses of short-half-life RIBs can be determined for a given target/vapor-transport system in advance of on-line operation, thereby ascertaining the feasibility of the system design for successful processing of a given isotope. In this article, molecular-flow-time theory and experimentally measured molecular-flow time data are given for serial- and parallel-coupled Ta metal RIB vapor-transport systems similar to those used at ISOL basedmore » RIB facilities. In addition, the effect of source type on the molecular-flow time properties of a given system is addressed, and a chemical passivation method for negating surface adsorption enthalpies for chemically active gaseous species on Ta surfaces is demonstrated.« less

  10. System Theoretic Frameworks for Mitigating Risk Complexity in the Nuclear Fuel Cycle

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Williams, Adam David; Mohagheghi, Amir H.; Cohn, Brian

    In response to the expansion of nuclear fuel cycle (NFC) activities -- and the associated suite of risks -- around the world, this project evaluated systems-based solutions for managing such risk complexity in multimodal and multi-jurisdictional international spent nuclear fuel (SNF) transportation. By better understanding systemic risks in SNF transportation, developing SNF transportation risk assessment frameworks, and evaluating these systems-based risk assessment frameworks, this research illustrated interdependency between safety, security, and safeguards risks is inherent in NFC activities and can go unidentified when each "S" is independently evaluated. Two novel system-theoretic analysis techniques -- dynamic probabilistic risk assessment (DPRA) andmore » system-theoretic process analysis (STPA) -- provide integrated "3S" analysis to address these interdependencies and the research results suggest a need -- and provide a way -- to reprioritize United States engagement efforts to reduce global nuclear risks. Lastly, this research identifies areas where Sandia National Laboratories can spearhead technical advances to reduce global nuclear dangers.« less

  11. Ratchet Effects in Active Matter Systems

    DOE PAGES

    Reichhardt, Cynthia Jane; Reichhardt, Charles

    2016-12-21

    Ratchet effects can arise for single or collectively interacting Brownian particles on an asymmetric substrate when a net dc transport is produced by an externally applied ac driving force or by periodically flashing the substrate. Recently, a new class of active ratchet systems that do not require the application of external driving has been realized through the use of active matter; they are self-propelled units that can be biological or nonbiological in nature. When active materials such as swimming bacteria interact with an asymmetric substrate, a net dc directed motion can arise even without external driving, opening a wealth ofmore » possibilities such as sorting, cargo transport, or micromachine construction. We review the current status of active matter ratchets for swimming bacteria, cells, active colloids, and swarming models, focusing on the role of particle-substrate interactions. Here, we describe ratchet reversals produced by collective effects and the use of active ratchets to transport passive particles. We discuss future directions including deformable substrates or particles, the role of different swimming modes, varied particle–particle interactions, and nondissipative effects.« less

  12. A continuation of base-line studies for environmentally monitoring space transportation systems at John F. Kennedy Space Center. Volume 3, part 2: Ichthyological studies, sailfin molly reproduction study

    NASA Technical Reports Server (NTRS)

    Snelson, F. F., Jr.

    1980-01-01

    The applicability of monitoring populations of Poccilia latipinna (sailfin molly) and its reproductive efforts as reliable indicators of environmental effects of aerospace activities in the Kennedy Space Center area was investigated. Results show that the sailfin molly experiences drastic fluctuations in population and reproductive success and is not an appropriate factor for monitoring to establish perturbations of the environment due to space transportation system related activities.

  13. Perturbed rhythmic activation of signaling pathways in mice deficient for Sterol Carrier Protein 2-dependent diurnal lipid transport and metabolism

    PubMed Central

    Jouffe, Céline; Gobet, Cédric; Martin, Eva; Métairon, Sylviane; Morin-Rivron, Delphine; Masoodi, Mojgan; Gachon, Frédéric

    2016-01-01

    Through evolution, most of the living species have acquired a time keeping system to anticipate daily changes caused by the rotation of the Earth. In all of the systems this pacemaker is based on a molecular transcriptional/translational negative feedback loop able to generate rhythmic gene expression with a period close to 24 hours. Recent evidences suggest that post-transcriptional regulations activated mostly by systemic cues play a fundamental role in the process, fine tuning the time keeping system and linking it to animal physiology. Among these signals, we consider the role of lipid transport and metabolism regulated by SCP2. Mice harboring a deletion of the Scp2 locus present a modulated diurnal accumulation of lipids in the liver and a perturbed activation of several signaling pathways including PPARα, SREBP, LRH-1, TORC1 and its upstream regulators. This defect in signaling pathways activation feedbacks upon the clock by lengthening the circadian period of animals through post-translational regulation of core clock regulators, showing that rhythmic lipid transport is a major player in the establishment of rhythmic mRNA and protein expression landscape. PMID:27097688

  14. Perturbed rhythmic activation of signaling pathways in mice deficient for Sterol Carrier Protein 2-dependent diurnal lipid transport and metabolism.

    PubMed

    Jouffe, Céline; Gobet, Cédric; Martin, Eva; Métairon, Sylviane; Morin-Rivron, Delphine; Masoodi, Mojgan; Gachon, Frédéric

    2016-04-21

    Through evolution, most of the living species have acquired a time keeping system to anticipate daily changes caused by the rotation of the Earth. In all of the systems this pacemaker is based on a molecular transcriptional/translational negative feedback loop able to generate rhythmic gene expression with a period close to 24 hours. Recent evidences suggest that post-transcriptional regulations activated mostly by systemic cues play a fundamental role in the process, fine tuning the time keeping system and linking it to animal physiology. Among these signals, we consider the role of lipid transport and metabolism regulated by SCP2. Mice harboring a deletion of the Scp2 locus present a modulated diurnal accumulation of lipids in the liver and a perturbed activation of several signaling pathways including PPARα, SREBP, LRH-1, TORC1 and its upstream regulators. This defect in signaling pathways activation feedbacks upon the clock by lengthening the circadian period of animals through post-translational regulation of core clock regulators, showing that rhythmic lipid transport is a major player in the establishment of rhythmic mRNA and protein expression landscape.

  15. Functional identification of activity-regulated, high-affinity glutamine transport in hippocampal neurons inhibited by riluzole.

    PubMed

    Erickson, Jeffrey D

    2017-07-01

    Glutamine (Gln) is considered the preferred precursor for the neurotransmitter pool of glutamate (Glu), the major excitatory transmitter in the mammalian CNS. Here, an activity-regulated, high-affinity Gln transport system is described in developing and mature neuron-enriched hippocampal cultures that is potently inhibited by riluzole (IC 50 1.3 ± 0.5 μM), an anti-glutamatergic drug, and is blocked by low concentrations of 2-(methylamino)isobutyrate (MeAIB), a system A transport inhibitor. K + -stimulated MeAIB transport displays an affinity (K m ) for MeAIB of 37 ± 1.2 μM, saturates at ~ 200 μM, is dependent on extracellular Ca 2+ , and is blocked by inhibition of voltage-gated Ca 2+ channels. Spontaneous MeAIB transport is also dependent on extracellullar Ca 2+ and voltage-gated calcium channels, but is also blocked by the Na + channel blocker tetrodotoxin, by Glu receptor antagonists, and by GABA indicating its dependence on intact neural circuits driven by endogenous glutamatergic activity. The transport of MeAIB itself does not rely on Ca 2+ , but on Na + ions, and is pH sensitive. Activity-regulated, riluzole-sensitive spontaneous and K + -stimulated transport is minimal at 7-8 days in vitro, coordinately induced during the next 2 weeks and is maximally expressed by days in vitro > 20; the known period for maturation of the Glu/Gln cycle and regulated pre-synaptic Glu release. Competition analyses with various amino acids indicate that Gln is the most likely physiological substrate. Activity-regulated Gln/MeAIB transport is not observed in astrocytes. The functional identification of activity-regulated, high-affinity, riluzole-sensitive Gln/MeAIB transport in hippocampal neurons may have important ramifications in the neurobiology of activity-stimulated pre-synaptic Glu release, the Glu/Gln cycle between astrocytes and neurons, and neuronal Glu-induced excitotoxicity. Cover Image for this issue: doi: 10.1111/jnc.13805. © 2017 International Society for Neurochemistry.

  16. Active Control of Flow Separation on a High-Lift System with Slotted Flap at High Reynolds Number

    NASA Technical Reports Server (NTRS)

    Khodadoust, Abdollah; Washburn, Anthony

    2007-01-01

    The NASA Energy Efficient Transport (EET) airfoil was tested at NASA Langley's Low- Turbulence Pressure Tunnel (LTPT) to assess the effectiveness of distributed Active Flow Control (AFC) concepts on a high-lift system at flight scale Reynolds numbers for a medium-sized transport. The test results indicate presence of strong Reynolds number effects on the high-lift system with the AFC operational, implying the importance of flight-scale testing for implementation of such systems during design of future flight vehicles with AFC. This paper describes the wind tunnel test results obtained at the LTPT for the EET high-lift system for various AFC concepts examined on this airfoil.

  17. Mission roles for the Solar Electric Propulsion Stage (SEPS) with the space transportation system. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Hammock, D. M.

    1975-01-01

    A study was conducted to determine the characteristics of solar electric propulsion stage (SEPS) for the space transportation system. Emphasis is placed on the rationale leading to the concepts for the development and operations program which enhances the cost effectiveness of the SEPS operating with the space transportation system. The approach in describing design concepts and configurations is concerned with the decision controlling factors and selection criteria. The mission roles for the SEPS in accomplishing proposed space activities are defined.

  18. Protecting surface transportation systems and patrons from terrorist activities : case studies of best security practices and a chronology of attacks

    DOT National Transportation Integrated Search

    1997-12-01

    This report documents the first phase of a continuing research effort carried out by the Norman Y. Mineta International Institute for Surface Transportation Policy Studies (IISTPS) on behalf of the U.S. Department of Transportation. It comprises a ch...

  19. 15th Annual Freight and Logistics Symposium : the future is front and center : the impacts of economic change on freight transportation.

    DOT National Transportation Integrated Search

    2011-12-01

    The U.S. transportation system stands at the center of virtually all economic : activity in the country today. Effects of a lengthy global recession are radically and : rapidly reshaping transportation priorities and needs. Now more than ever, freigh...

  20. 77 FR 19680 - Extension of Agency Information Collection Activity Under OMB Review: Rail Transportation Security

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-02

    ... receivers of certain hazardous materials; and passenger railroad carriers, including each carrier operating light rail or heavy rail transit service on track that is part of the general railroad system of transportation and rail transit systems. Also, these persons are required to report significant security concerns...

  1. 25 CFR 170.806 - What is an IRR Transportation Facilities Maintenance Management System?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... facility maintenance activities. It will be used to extend the service life of an IRR transportation facility, ensure safety, and report future funding needs to the Secretary. BIA will develop the IRR TFMMS. ... Management System? 170.806 Section 170.806 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND...

  2. 25 CFR 170.806 - What is an IRR Transportation Facilities Maintenance Management System?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... facility maintenance activities. It will be used to extend the service life of an IRR transportation facility, ensure safety, and report future funding needs to the Secretary. BIA will develop the IRR TFMMS. ... Management System? 170.806 Section 170.806 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND...

  3. 25 CFR 170.806 - What is an IRR Transportation Facilities Maintenance Management System?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... facility maintenance activities. It will be used to extend the service life of an IRR transportation facility, ensure safety, and report future funding needs to the Secretary. BIA will develop the IRR TFMMS. ... Management System? 170.806 Section 170.806 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND...

  4. Tracking small mountainous river derived terrestrial organic carbon across the active margin marine environment

    NASA Astrophysics Data System (ADS)

    Childress, L. B.; Blair, N. E.; Orpin, A. R.

    2015-12-01

    Active margins are particularly efficient in the burial of organic carbon due to the close proximity of highland sources to marine sediment sinks and high sediment transport rates. Compared with passive margins, active margins are dominated by small mountainous river systems, and play a unique role in marine and global carbon cycles. Small mountainous rivers drain only approximately 20% of land, but deliver approximately 40% of the fluvial sediment to the global ocean. Unlike large passive margin systems where riverine organic carbon is efficiently incinerated on continental shelves, small mountainous river dominated systems are highly effective in the burial and preservation of organic carbon due to the rapid and episodic delivery of organic carbon sourced from vegetation, soil, and rock. To investigate the erosion, transport, and burial of organic carbon in active margin small mountainous river systems we use the Waipaoa River, New Zealand. The Waipaoa River, and adjacent marine depositional environment, is a system of interest due to a large sediment yield (6800 tons km-2 yr-1) and extensive characterization. Previous studies have considered the biogeochemistry of the watershed and tracked the transport of terrestrially derived sediment and organics to the continental shelf and slope by biogeochemical proxies including stable carbon isotopes, lignin phenols, n-alkanes, and n-fatty acids. In this work we expand the spatial extent of investigation to include deep sea sediments of the Hikurangi Trough. Located in approximately 3000 m water depth 120 km from the mouth of the Waipaoa River, the Hikurangi Trough is the southern extension of the Tonga-Kermadec-Hikurangi subduction system. Piston core sediments collected by the National Institute of Water and Atmospheric Research (NIWA, NZ) in the Hikurangi Trough indicate the presence of terrestrially derived material (lignin phenols), and suggest a continuum of deposition, resuspension, and transport across the margin. Based on tephra beds identified within the sediments, this material was likely transported by a series of turbidite events, delivered to the Hikurangi Trough through Poverty Canyon.

  5. Blood-brain barrier permeation and efflux exclusion of anticholinergics used in the treatment of overactive bladder.

    PubMed

    Chancellor, Michael B; Staskin, David R; Kay, Gary G; Sandage, Bobby W; Oefelein, Michael G; Tsao, Jack W

    2012-04-01

    Overactive bladder (OAB) is a common condition, particularly in the elderly. Anticholinergic agents are the mainstay of pharmacological treatment of OAB; however, many anticholinergics can cross the blood-brain barrier (BBB) and may cause central nervous system (CNS) effects, including cognitive deficits, which can be especially detrimental in older patients. Many anticholinergics have the potential to cause adverse CNS effects due to muscarinic (M(1)) receptor binding in the brain. Of note, permeability of the BBB increases with age and can also be affected by trauma, stress, and some diseases and medications. Passive crossing of a molecule across the BBB into the brain is dependent upon its physicochemical properties. Molecular characteristics that hinder passive BBB penetration include a large molecular size, positive or negative ionic charge at physiological pH, and a hydrophilic structure. Active transport across the BBB is dependent upon protein-mediated transporter systems, such as that of permeability-glycoprotein (P-gp), which occurs only for P-gp substrates, such as trospium chloride, darifenacin and fesoterodine. Reliance on active transport can be problematic since genetic polymorphisms of P-gp exist, and many commonly used drugs and even some foods are P-gp inhibitors or are substrates themselves and, due to competition, can reduce the amount of the drug that is actively transported out of the CNS. Therefore, for drugs that are preferred not to cross into the CNS, such as potent anticholinergics intended for the bladder, it is optimal to have minimal passive crossing of the BBB, although it may also be beneficial for the drug to be a substrate for an active efflux transport system. Anticholinergics demonstrate different propensities to cross the BBB. Darifenacin, fesoterodine and trospium chloride are substrates for P-gp and, therefore, are actively transported away from the brain. In addition, trospium chloride has not been detected in cerebrospinal fluid assays and does not appear to have significant CNS penetration. This article reviews the properties of anticholinergics that affect BBB penetration and active transport out of the CNS, discusses issues of increased BBB permeability in patients with OAB, and examines the clinical implications of BBB penetration on adverse events associated with anticholinergics.

  6. Systems and methods for solar energy storage, transportation, and conversion utilizing photochemically active organometallic isomeric compounds and solid-state catalysts

    DOEpatents

    Vollhardt, K. Peter C.; Segalman, Rachel A; Majumdar, Arunava; Meier, Steven

    2015-02-10

    A system for converting solar energy to chemical energy, and, subsequently, to thermal energy includes a light-harvesting station, a storage station, and a thermal energy release station. The system may include additional stations for converting the released thermal energy to other energy forms, e.g., to electrical energy and mechanical work. At the light-harvesting station, a photochemically active first organometallic compound, e.g., a fulvalenyl diruthenium complex, is exposed to light and is photochemically converted to a second, higher-energy organometallic compound, which is then transported to a storage station. At the storage station, the high-energy organometallic compound is stored for a desired time and/or is transported to a desired location for thermal energy release. At the thermal energy release station, the high-energy organometallic compound is catalytically converted back to the photochemically active organometallic compound by an exothermic process, while the released thermal energy is captured for subsequent use.

  7. 76 FR 12209 - Access to Aircraft Situation Display (ASDI) and National Airspace System Status Information (NASSI)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-04

    ..., a recent history of violent terrorist activity in the geographic area in which the transportation is...-oriented security concern'' that requires an employee to travel on a company plane for business and... history of violent terrorist activity in the geographic area in which the transportation is provided, or a...

  8. A wireless electronic monitoring system for securing milk from farm to processor

    NASA Astrophysics Data System (ADS)

    Womble, Phillip; Hopper, Lindsay; Thompson, Chris; Alexander, Suraj M.; Crist, William; Payne, Fred; Stombaugh, Tim; Paschal, Jon; Moore, Ryan; Luck, Brian; Tabayehnejab, Nasrin

    2008-04-01

    The Department of Homeland Security and the Department of Health and Human Services have targeted bulk food contamination as a focus for attention. The contamination of bulk food poses a high consequence threat to our society. Milk transport falls into three of the 17 targeted NIPP (National Infrastructure Protection Plan) sectors including agriculture-food, public health, and commercial facilities. Minimal security safeguards have been developed for bulk milk transport. The current manual methods of securing milk are paper intensive and prone to errors. The bulk milk transportation sector requires a security enhancement that will both reduce recording errors and enable normal transport activities to occur while providing security against unauthorized access. Milk transportation companies currently use voluntary seal programs that utilize plastic, numbered seals on milk transport tank openings. Our group has developed a Milk Transport Security System which is an electromechanical access control and communication system that assures the secure transport of milk, milk samples, milk data, and security data between locations and specifically between dairy farms, transfer stations, receiving stations, and milk plants. It includes a security monitoring system installed on the milk transport tank, a hand held device, optional printers, data server, and security evaluation software. The system operates automatically and requires minimal or no attention by the bulk milk hauler/sampler. The system is compatible with existing milk transport infrastructure, and has the support of the milk producers, milk transportation companies, milk marketing agencies, and dairy processors. The security protocol developed is applicable for transport of other bulk foods both nationally and internationally. This system adds significantly to the national security infrastructure for bulk food transport. We are currently demonstrating the system in central Kentucky and will report on the results of the demonstration.

  9. Increased ubiquitination and reduced plasma membrane trafficking of placental amino acid transporter SNAT-2 in human IUGR.

    PubMed

    Chen, Yi-Yung; Rosario, Fredrick J; Shehab, Majida Abu; Powell, Theresa L; Gupta, Madhulika B; Jansson, Thomas

    2015-12-01

    Placental amino acid transport is decreased in intrauterine growth restriction (IUGR); however, the underlying mechanisms remain largely unknown. We have shown that mechanistic target of rapamycin (mTOR) signalling regulates system A amino acid transport by modulating the ubiquitination and plasma membrane trafficking of sodium-coupled neutral amino acid transporter 2 (SNAT-2) in cultured primary human trophoblast cells. We hypothesize that IUGR is associated with (1) inhibition of placental mTORC1 and mTORC2 signalling pathways, (2) increased amino acid transporter ubiquitination in placental homogenates and (3) decreased protein expression of SNAT-2 in the syncytiotrophoblast microvillous plasma membrane (MVM). To test this hypothesis, we collected placental tissue and isolated MVM from women with pregnancies complicated by IUGR (n=25) and gestational age-matched women with appropriately grown control infants (n=19, birth weights between the twenty-fifth to seventy-fifth percentiles). The activity of mTORC1 and mTORC2 was decreased whereas the protein expression of the ubiquitin ligase NEDD4-2 (neural precursor cell expressed developmentally down-regulated protein 4-2; +72%, P<0.0001) and the ubiquitination of SNAT-2 (+180%, P<0.05) were increased in homogenates of IUGR placentas. Furthermore, IUGR was associated with decreased system A amino acid transport activity (-72%, P<0.0001) and SNAT-1 (-42%, P<0.05) and SNAT-2 (-31%, P<0.05) protein expression in MVM. In summary, these findings are consistent with the possibility that decreased placental mTOR activity causes down-regulation of placental system A activity by shifting SNAT-2 trafficking towards proteasomal degradation, thereby contributing to decreased fetal amino acid availability and restricted fetal growth in IUGR. © 2015 Authors; published by Portland Press Limited.

  10. Increased ubiquitination and reduced plasma membrane trafficking of placental amino acid transporter SNAT-2 in human IUGR

    PubMed Central

    Rosario, Fredrick J.; Shehab, Majida Abu; Powell, Theresa L.; Gupta, Madhulika B.; Jansson, Thomas

    2015-01-01

    Placental amino acid transport is decreased in intrauterine growth restriction (IUGR); however, the underlying mechanisms remain largely unknown. We have shown that mechanistic target of rapamycin (mTOR) signalling regulates system A amino acid transport by modulating the ubiquitination and plasma membrane trafficking of sodium-coupled neutral amino acid transporter 2 (SNAT-2) in cultured primary human trophoblast cells. We hypothesize that IUGR is associated with (1) inhibition of placental mTORC1 and mTORC2 signalling pathways, (2) increased amino acid transporter ubiquitination in placental homogenates and (3) decreased protein expression of SNAT-2 in the syncytiotrophoblast microvillous plasma membrane (MVM). To test this hypothesis, we collected placental tissue and isolated MVM from women with pregnancies complicated by IUGR (n=25) and gestational age-matched women with appropriately grown control infants (n=19, birth weights between the twenty-fifth to seventy-fifth percentiles). The activity of mTORC1 and mTORC2 was decreased whereas the protein expression of the ubiquitin ligase NEDD4-2 (neural precursor cell expressed developmentally down-regulated protein 4-2; +72%, P<0.0001) and the ubiquitination of SNAT-2 (+180%, P<0.05) were increased in homogenates of IUGR placentas. Furthermore, IUGR was associated with decreased system A amino acid transport activity (–72%, P<0.0001) and SNAT-1 (–42%, P<0.05) and SNAT-2 (–31%, P<0.05) protein expression in MVM. In summary, these findings are consistent with the possibility that decreased placental mTOR activity causes down-regulation of placental system A activity by shifting SNAT-2 trafficking towards proteasomal degradation, thereby contributing to decreased fetal amino acid availability and restricted fetal growth in IUGR. PMID:26374858

  11. Active transportation environments surrounding Canadian schools.

    PubMed

    O'Loghlen, Sean; Pickett, J William; Janssen, Ian

    2011-01-01

    Walking or cycling to school represents an opportunity for children to engage in physical activity. The study objectives were to: 1) describe active transportation policies, programs, and built environments of Canadian schools and their surrounding neighbourhoods, and 2) document variations based on urban-rural location and school type (primary vs. secondary vs. mixed primary/secondary schools). 397 schools from across Canada were studied. A school administrator completed a questionnaire and responses were used to assess schools' policies and programs related to active transportation and the safety and aesthetics of their respective neighbourhoods. Built environment features in a 1 km-radius circular buffer around each school were measured using geographic information systems. Greater than 70% of schools had passive policies (e.g., skateboards permitted on school grounds) and facilities (e.g., bicycle racks in secure area to avoid theft) to encourage bicycle and small-wheeled vehicle use. Less than 40% of schools had active programs designed to encourage active transportation, such as organized 'walk to school' days. Garbage in the streets, crime and substance abuse were barriers in most school neighbourhoods. Approximately 42% of schools were located on high-speed roads not amenable to active transportation and 14% did not have a sidewalk leading to the school. Secondary schools had less favourable active transportation policies/programs and neighbourhood safety/aesthetics compared to primary schools. Rural schools had less favourable built environments than urban schools. Canadian children, particularly those from rural areas, face a number of impediments to active transportation as a method of travelling to school.

  12. Reduced placental amino acid transport in response to maternal nutrient restriction in the baboon.

    PubMed

    Pantham, Priyadarshini; Rosario, Fredrick J; Nijland, Mark; Cheung, Alex; Nathanielsz, Peter W; Powell, Theresa L; Galan, Henry L; Li, Cun; Jansson, Thomas

    2015-10-01

    Intrauterine growth restriction increases the risk of perinatal complications and predisposes the infant to diabetes and cardiovascular disease in later life. Mechanisms by which maternal nutrient restriction (MNR) reduces fetal growth are poorly understood. We hypothesized that MNR decreases placental amino acid (AA) transporter activity, leading to reduced transplacental transfer of AAs. Pregnant baboons were fed either a control (ad libitum, n = 7), or MNR diet (70% of control diet, n = 7) from gestational day (GD) 30. At GD 165 (0.9 gestation), placentas (n = 7 in each group) were collected, and microvillous plasma membrane vesicles (MVM) isolated. MVM system A and system L AA transport was determined in vitro using radiolabeled substrates and rapid filtration techniques. In vivo transplacental AA transport was assessed by infusing nine (13)C- or (2)H-labeled essential AA as a bolus into the maternal circulation (n = 5 control, n = 4 MNR) at cesarean section. A fetal vein-to-maternal artery mole percent excess ratio for each essential AA was calculated. Fetal and placental weights were significantly reduced in the MNR group compared with controls (P < 0.01). The activity of system A and system L was markedly reduced by 73 and 84%, respectively, in MVM isolated from baboon placentas at GD 165 following MNR (P < 0.01). In vivo, the fetal vein-to-maternal artery mole percent excess ratio was significantly reduced for leucine, isoleucine, methionine, phenylalanine, threonine, and tryptophan in MNR baboons (P < 0.05). This is the first study to investigate placental AA transport in a nonhuman primate model of MNR. We demonstrate that the downregulation of system A and system L activity in syncytiotrophoblast MVM in MNR leads to decreased transplacental AA transport and, consequently, reduced circulating fetal AA concentrations, a potential mechanism linking maternal undernutrition to reduced fetal growth. Copyright © 2015 the American Physiological Society.

  13. Inhibition of Human Drug Transporter Activities by the Pyrethroid Pesticides Allethrin and Tetramethrin

    PubMed Central

    Chedik, Lisa; Bruyere, Arnaud; Le Vee, Marc; Stieger, Bruno; Denizot, Claire; Parmentier, Yannick; Potin, Sophie; Fardel, Olivier

    2017-01-01

    Pyrethroids are widely-used chemical insecticides, to which humans are commonly exposed, and known to alter functional expression of drug metabolizing enzymes. Limited data have additionally suggested that drug transporters, that constitute key-actors of the drug detoxification system, may also be targeted by pyrethroids. The present study was therefore designed to analyze the potential regulatory effects of these pesticides towards activities of main ATP-binding cassette (ABC) and solute carrier (SLC) drug transporters, using transporter-overexpressing cells. The pyrethroids allethrin and tetramethrin were found to inhibit various ABC and SLC drug transporters, including multidrug resistance-associated protein (MRP) 2, breast cancer resistance protein (BCRP), organic anion transporter polypeptide (OATP) 1B1, organic anion transporter (OAT) 3, multidrug and toxin extrusion transporter (MATE) 1, organic cation transporter (OCT) 1 and OCT2, with IC50 values however ranging from 2.6 μM (OCT1 inhibition by allethrin) to 77.6 μM (OAT3 inhibition by tetramethrin) and thus much higher than pyrethroid concentrations (in the nM range) reached in environmentally pyrethroid-exposed humans. By contrast, allethrin and tetramethrin cis-stimulated OATP2B1 activity and failed to alter activities of OATP1B3, OAT1 and MATE2-K, whereas P-glycoprotein activity was additionally moderately inhibited. Twelve other pyrethoids used at 100 μM did not block activities of the various investigated transporters, or only moderately inhibited some of them (inhibition by less than 50%). In silico analysis of structure-activity relationships next revealed that molecular parameters, including molecular weight and lipophilicity, are associated with transporter inhibition by allethrin/tetramethrin and successfully predicted transporter inhibition by the pyrethroids imiprothrin and prallethrin. Taken together, these data fully demonstrated that two pyrethoids, i.e., allethrin and tetramethrin, can act as regulators of the activity of various ABC and SLC drug transporters, but only when used at high and non-relevant concentrations, making unlikely any contribution of these transporter activity alterations to pyrethroid toxicity in environmentally exposed humans. PMID:28099443

  14. Function of fusion regulatory proteins (FRPs) in immune cells and virus-infected cells.

    PubMed

    Tsurudome, M; Ito, Y

    2000-01-01

    Two molecules that regulate cell fusion have been identified and designated fusion regulatory protein-1 (FRP-1) and FRP-2. FRP-1 is a complex composed of a glycosylated heavy chain and a nonglycosylated light chain that are disulfide linked. FRP-1 heavy chain is identical to 4F2/CD98 heavy chain, whereas FRP-2 is identical to integrin alpha3 subunit. The FRP-1 heavy chain is a multifunctional molecule: that is, fusion regulator, amino acid transporter, integrin regulator, comitogenic factor, Na+-Ca2+ exchanger, oncogenic protein, and so on. Several aspects of the structure and function of the FRP-1 system are reviewed: fusion regulatory molecular mechanisms, cross-talk between the FRP-1 and integrin, the FRP-1 system as amino acid transporter, and FRP-1-mediated T-cell activation. The FRP-1 system is involved in virus-mediated cell fusion and multinucleated giant cell formation of blood monocytes. Monoclonal antibodies against human FRP-1 heavy chain induce polykaryocytes that have properties as osteoclasts. Multiple steps participate in molecular mechanisms regulating cell fusion. The FRP-1 heavy chain supports amino acid transport activity and the FRP-1 light chains have recently been cloned as amino acid transporters that require association with the heavy chain to exhibit their activity. Novel pathways for monocyte-dependent regulation of T-cell activation have recently been found that are mediated by the FRP-1 system. In conclusion, the FRP-1 molecules are essential factors for basic cellular functions.

  15. In situ calibration of neutron activation system on the large helical device

    NASA Astrophysics Data System (ADS)

    Pu, N.; Nishitani, T.; Isobe, M.; Ogawa, K.; Kawase, H.; Tanaka, T.; Li, S. Y.; Yoshihashi, S.; Uritani, A.

    2017-11-01

    In situ calibration of the neutron activation system on the Large Helical Device (LHD) was performed by using an intense 252Cf neutron source. To simulate a ring-shaped neutron source, we installed a railway inside the LHD vacuum vessel and made a train loaded with the 252Cf source run along a typical magnetic axis position. Three activation capsules loaded with thirty pieces of indium foils stacked with total mass of approximately 18 g were prepared. Each capsule was irradiated over 15 h while the train was circulating. The activation response coefficient (9.4 ± 1.2) × 10-8 of 115In(n, n')115mIn reaction obtained from the experiment is in good agreement with results from three-dimensional neutron transport calculations using the Monte Carlo neutron transport simulation code 6. The activation response coefficients of 2.45 MeV birth neutron and secondary 14.1 MeV neutron from deuterium plasma were evaluated from the activation response coefficient obtained in this calibration experiment with results from three-dimensional neutron calculations using the Monte Carlo neutron transport simulation code 6.

  16. Malate-aspartate shuttle and exogenous NADH/cytochrome c electron transport pathway as two independent cytosolic reducing equivalent transfer systems.

    PubMed

    Abbrescia, Daniela Isabel; La Piana, Gianluigi; Lofrumento, Nicola Elio

    2012-02-15

    In mammalian cells aerobic oxidation of glucose requires reducing equivalents produced in glycolytic phase to be channelled into the phosphorylating respiratory chain for the reduction of molecular oxygen. Data never presented before show that the oxidation rate of exogenous NADH supported by the malate-aspartate shuttle system (reconstituted in vitro with isolated liver mitochondria) is comparable to the rate obtained on activation of the cytosolic NADH/cytochrome c electron transport pathway. The activities of these two reducing equivalent transport systems are independent of each other and additive. NADH oxidation induced by the malate-aspartate shuttle is inhibited by aminooxyacetate and by rotenone and/or antimycin A, two inhibitors of the respiratory chain, while the NADH/cytochrome c system remains insensitive to all of them. The two systems may simultaneously or mutually operate in the transfer of reducing equivalents from the cytosol to inside the mitochondria. In previous reports we suggested that the NADH/cytochrome c system is expected to be functioning in apoptotic cells characterized by the presence of cytochrome c in the cytosol. As additional new finding the activity of reconstituted shuttle system is linked to the amount of α-ketoglutarate generated inside the mitochondria by glutamate dehydrogenase rather than by aspartate aminotransferase. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Motion-base simulator results of advanced supersonic transport handling qualities with active controls

    NASA Technical Reports Server (NTRS)

    Feather, J. B.; Joshi, D. S.

    1981-01-01

    Handling qualities of the unaugmented advanced supersonic transport (AST) are deficient in the low-speed, landing approach regime. Consequently, improvement in handling with active control augmentation systems has been achieved using implicit model-following techniques. Extensive fixed-based simulator evaluations were used to validate these systems prior to tests with full motion and visual capabilities on a six-axis motion-base simulator (MBS). These tests compared the handling qualities of the unaugmented AST with several augmented configurations to ascertain the effectiveness of these systems. Cooper-Harper ratings, tracking errors, and control activity data from the MBS tests have been analyzed statistically. The results show the fully augmented AST handling qualities have been improved to an acceptable level.

  18. 78 FR 68501 - Agency Information Collection Activity Under OMB Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-14

    ... 3038 of the Transportation Equity Act for the 21st Century (TEA-21), Public Law 105-85, as amended by....S. transportation system. TEA-21 authorized FTA's OTRB Accessibility Program to assist OTRB...

  19. Control of the Water Transport Activity of Barley HvTIP3;1 Specifically Expressed in Seeds.

    PubMed

    Utsugi, Shigeko; Shibasaka, Mineo; Maekawa, Masahiko; Katsuhara, Maki

    2015-09-01

    Tonoplast intrinsic proteins (TIPs) are involved in the transport and storage of water, and control intracellular osmotic pressure by transporting material related to the water potential of cells. In the present study, we focused on HvTIP3;1 during the periods of seed development and desiccation in barley. HvTIP3;1 was specifically expressed in seeds. An immunochemical analysis showed that HvTIP3;1 strongly accumulated in the aleurone layers and outer layers of barley seeds. The water transport activities of HvTIP3;1 and HvTIP1;2, which also accumulated in seeds, were measured in the heterologous expression system of Xenopus oocytes. When they were expressed individually, HvTIP1;2 transported water, whereas HvTIP3;1 did not. However, HvTIP3;1 exhibited water transport activity when co-expressed with HvTIP1;2 in oocytes, and this activity was higher than when HvTIP1;2 was expressed alone. This is the first report to demonstrate that the water permeability of a TIP aquaporin was activated when co-expressed with another TIP. The split-yellow fluorescent protein (YFP) system in onion cells revealed that HvTIP3;1 interacted with HvTIP1;2 to form a heterotetramer in plants. These results suggest that HvTIP3;1 functions as an active water channel to regulate water movement through tissues during the periods of seed development and desiccation. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  20. Transportation and the handicapped

    NASA Technical Reports Server (NTRS)

    Richardson, H. H.

    1974-01-01

    Some statistics on the handicapped in relation to transportation are considered, and some of the major deterrents to travel in our existing systems are outlined. Some of the benefits of enhanced mobility are identified and examples are given of minimizing travel barriers. Finally, some of DOT's activities that are directed toward improving transportation for the handicapped are outlined.

  1. The Societal Costs and Benefits of Commuter Bicycling: Simulating the Effects of Specific Policies Using System Dynamics Modeling

    PubMed Central

    Connor, Jennie; Witten, Karen; Kearns, Robin; Rees, David; Woodward, Alistair

    2014-01-01

    Background: Shifting to active modes of transport in the trip to work can achieve substantial co-benefits for health, social equity, and climate change mitigation. Previous integrated modeling of transport scenarios has assumed active transport mode share and has been unable to incorporate acknowledged system feedbacks. Objectives: We compared the effects of policies to increase bicycle commuting in a car-dominated city and explored the role of participatory modeling to support transport planning in the face of complexity. Methods: We used system dynamics modeling (SDM) to compare realistic policies, incorporating feedback effects, nonlinear relationships, and time delays between variables. We developed a system dynamics model of commuter bicycling through interviews and workshops with policy, community, and academic stakeholders. We incorporated best available evidence to simulate five policy scenarios over the next 40 years in Auckland, New Zealand. Injury, physical activity, fuel costs, air pollution, and carbon emissions outcomes were simulated. Results: Using the simulation model, we demonstrated the kinds of policies that would likely be needed to change a historical pattern of decline in cycling into a pattern of growth that would meet policy goals. Our model projections suggest that transforming urban roads over the next 40 years, using best practice physical separation on main roads and bicycle-friendly speed reduction on local streets, would yield benefits 10–25 times greater than costs. Conclusions: To our knowledge, this is the first integrated simulation model of future specific bicycling policies. Our projections provide practical evidence that may be used by health and transport policy makers to optimize the benefits of transport bicycling while minimizing negative consequences in a cost-effective manner. The modeling process enhanced understanding by a range of stakeholders of cycling as a complex system. Participatory SDM can be a helpful method for integrating health and environmental outcomes in transport and urban planning. Citation: Macmillan A, Connor J, Witten K, Kearns R, Rees D, Woodward A. 2014. The societal costs and benefits of commuter bicycling: simulating the effects of specific policies using system dynamics modeling. Environ Health Perspect 122:335–344; http://dx.doi.org/10.1289/ehp.1307250 PMID:24496244

  2. Merging long range transportation planning with public health: a case study from Utah's Wasatch Front.

    PubMed

    Burbidge, Shaunna K

    2010-01-01

    US transportation systems have been identified as a problem for public health, as they often encourage automobile transportation and discourage physical activity. This paper provides a case study examination of the Public Health Component of the Wasatch Front Regional Council's Regional Transportation Plan. This plan provides an example of what transportation planners at Utah's largest metropolitan planning organization (MPO) are doing to encourage physical activity through transportation. Existing active living research was used to guide recommendations using a process that included a comprehensive literature review and a review of existing state programs, advisory group and stakeholder meetings, and policy recommendations based on existing local conditions. Stakeholders from a diversity of background and interests came together with one common goal: to improve public health. Based on this collaborative process, nine policy approaches were specifically recommended for approval and integration in the Wasatch Front Regional Transportation Plan. By using current research as a guide and integrating a variety of interests, the Wasatch Front Regional Council is setting a new standard for a collaborative multi-modal focus in transportation planning, which can be replicated nationwide.

  3. Adolescents who engage in active school transport are also more active in other contexts: A space-time investigation.

    PubMed

    Stewart, Tom; Duncan, Scott; Schipperijn, Jasper

    2017-01-01

    Although active school travel (AST) is important for increasing moderate-to-vigorous physical activity (MVPA), it is unclear how AST is related to context-specific physical activity and non-school travel. This study investigated how school travel is related to physical activity and travel behaviours across time- and space-classified domains. A total of 196 adolescents wore a Global Positioning System receiver and an accelerometer for 7 days. All data were classified into one of four domains: home, school, transport, or leisure. Generalized linear mixed models were used to compare domain-specific PA and non-school trips between active and passive school travellers. Active travellers accumulated 13 and 14 more min of MVPA on weekdays and weekend days, respectively. They also spent 15min less time in vehicular travel during non-school trips, and accrued an additional 9min of MVPA while walking on weekend days. However, those with no AST still achieved most of their MVPA in the transport domain. AST is related to out-of-school physical activity and transportation, but transport is also important for those who do not use AST. As such, future studies should consider overall mobility and destinations other than school when assessing travel and physical activity behaviours. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Conservation and renewable energy technologies for transportation

    NASA Astrophysics Data System (ADS)

    1990-11-01

    The Office of Transportation Technologies (OTT) is charged with long-term, high-risk, and potentially high-payoff research and development of promising transportation technologies that are unlikely to be undertaken by the private sector alone. OTT activities are designed to develop an advanced technology base within the U.S. transportation industry for future manufacture of more energy-efficient, fuel-flexible, and environmentally sound transportation systems. OTT operations are focused on three areas: advanced automotive propulsion systems including gas turbines, low heat rejection diesel, and electric vehicle technologies; advanced materials development and tribology research; and research, development, demonstration, test, and evaluation (including field testing in fleet operations) of alternative fuels. Five papers describing the transportation technologies program have been indexed separately for inclusion on the data base.

  5. Gulf of Mexico Helicopter Offshore System Technologies Recommended Development Path

    NASA Technical Reports Server (NTRS)

    Koenke, Edmund J.; Williams, Larry; Calafa, Caesar

    1999-01-01

    The National Aeronautics and Space Administration (NASA) Advanced Air Transportation Technologies (AATT) project in cooperation with the Department of Transportation (DOT) Volpe National Transportation Systems Center (VNTSC) contracted with the System Resources Corporation (SRC) for the evaluation of the existing environment and the identification of user and service provider needs in the Gulf of Mexico low-altitude Offshore Sector. The results of this contractor activity are reported in the Gulf of Mexico Helicopter Offshore System Technologies Engineering Needs Assessment. A recommended system design and transition strategy was then developed to satisfy the identified needs within the constraints of the environment. This work, also performed under contract to NASA, is the subject of this report.

  6. Final Report for the Center for Momentum Transport and Flow Organization (CMTFO)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tynan, George R.

    The Center for Momentum Transport and Flow Organization (CMTFO) was established in 2009 as a multi-institutional U.S. DOE Plasma Science Center, with a focus on the fundamental physics mechanisms that lead to the transport of momentum within fusion and astrophysical plasma systems, and the subsequent formation of ordered behavior in such systems. It was funded in two tranches; this report covers the activities supported by the second period of funding which ran from May 2012 through May 2016.

  7. Constitutive androstane receptor upregulates Abcb1 and Abcg2 at the blood-brain barrier after CITCO activation.

    PubMed

    Lemmen, Julia; Tozakidis, Iasson E P; Bele, Prachee; Galla, Hans-Joachim

    2013-03-21

    ATP-driven efflux transporters are considered to be the major hurdle in the treatment of central nervous system (CNS) diseases. Abcb1 (P-glycoprotein) and Abcg2 (breast cancer resistance protein/brain multidrug resistance protein) belong to the best known ABC-transporters. These ABC-transporters limit the permeability of the blood-brain barrier and protect the brain against toxic compounds in the blood but on the other hand they also reduce the efficacy of CNS pharmacotherapy. Even after 40 years of extensive research, the regulatory mechanisms of these efflux transporters are still not completely understood. To unravel the efflux transporter regulation, we analyzed the effect of the nuclear receptor CAR (constitutive androstane receptor) on the expression of Abcb1 and Abcg2 in primary cultures of porcine brain capillary endothelial cells (PBCEC). CAR is a xenobiotic-activated transcription factor, which is, like the other important nuclear receptor pregnane X receptor (PXR), highly expressed in barrier tissue and known to be a positive regulator of ABC-transporters. We demonstrate that activation of porcine CAR by the human CAR (hCAR) ligand CITCO (6-(4-chlorophenyl)-imidazo[2,1-b]thiazole-5-carbaldehyde) leads to an up-regulation of both transporters, whereas the mouse-specific CAR ligand TCPOBOP (1,4-bis-[2-(3,5-dichloropyridyloxy)]benzene) had no effect on transporter expression. The stimulation of PBCEC with CITCO caused a significant up-regulation of both efflux-transporters on RNA-level, protein level and transport level. Furthermore the additional application of a CAR inhibitor significantly decreased the transporter expression to control niveau. In conclusion our data prove CAR activation only by the human ligand CITCO leading to an increased ABC-transporter expression and transport activity. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Volpe Center work on ITS helps forge new partnerships

    DOT National Transportation Integrated Search

    1997-01-01

    Intelligent Transportation Systems (ITS) offer the promise of increased efficiency and safety in our transportation infrastructure. The Volpe Center is actively providing support for the development and deployment of ITS technologies as well as ident...

  9. To develop effective strategies for mainstreaming intelligent transportation systems (ITS).

    DOT National Transportation Integrated Search

    2002-11-01

    This report investigates factors affecting ITS implementation as a mainstream transportation planning activity. It draws upon a detailed literature review, interviews with fifty-one leaders from a cross-section of jurisdictions and agencies in ...

  10. Seminar and TRB conference attendance : year 9.

    DOT National Transportation Integrated Search

    2012-12-01

    Students from the three campuses of the University of Alabama of System are engaged in a variety of transportation related research activities. This project intended to provide a forum for transportation students to present their research results to ...

  11. Selenium-containing organic nanoparticles as silent precursors for ultra-sensitive thiol-responsive transmembrane anion transport.

    PubMed

    Lang, Chao; Zhang, Xin; Dong, Zeyuan; Luo, Quan; Qiao, Shanpeng; Huang, Zupeng; Fan, Xiaotong; Xu, Jiayun; Liu, Junqiu

    2016-02-07

    An anion transporter with a selenoxide group was able to form nanoparticles in water, whose activity was fully turned off due to the aggregation effect. The formed nanoparticles have a uniform size and can be readily dispersed in water at high concentrations. Turn-on of the nanoparticles by reducing molecules is proposed to be a combined process, including the reduction of selenoxide to selenide, disassembly of the nanoparticles and location of the transporter to the lipid membrane. Accordingly, a special acceleration phase can be observed in the turn-on kinetic curves. Since turn-on of the nanoparticles is quantitatively related to the amount of reductant, the nanoparticles can be activated in a step-by-step manner. Due to the sensibility of this system to thiols, cysteine can be detected at low nanomolar concentrations. This ultra-sensitive thiol-responsive transmembrane anion transport system is quite promising in biological applications.

  12. Improving efficiency of transport fuels production by thermal hydrolysis of waste activated sludge

    NASA Astrophysics Data System (ADS)

    Gulshin, Igor

    2017-10-01

    The article deals with issues of transport biofuels. Transport biofuels are an important element of a system of energy security. Moreover, as part of a system it is inextricably linked to the urban, rural or industrial infrastructure. The paper discusses methods of increasing the yield of biogas from anaerobic digesters at wastewater treatment plants. The thermal hydrolysis method was considered. The main advantages and drawbacks of this method were analyzed. The experimental biomass (from SNDOD-bioreactor) and high-organic substrate have been previously studied by respirometry methods. A biomethane potential of the investigated organic substrate has high rates because of substrate composition (the readily biodegradable substrate in the total composition takes about 85%). Waste activated sludge from SNDOD-bioreactor can be used for biofuel producing with high efficiency especially with pre-treatment like a thermal hydrolysis. Further studies have to consider the possibility of withdrawing inhibitors from waste activated sludge.

  13. Transport of BMAA into Neurons and Astrocytes by System xc.

    PubMed

    Albano, Rebecca; Lobner, Doug

    2018-01-01

    The study of the mechanism of β-N-methylamino-L-alanine (BMAA) neurotoxicity originally focused on its effects at the N-methyl-D-aspartate (NMDA) receptor. In recent years, it has become clear that its mechanism of action is more complicated. First, there are certain cell types, such as motor neurons and cholinergic neurons, where the dominate mechanism of toxicity is through action at AMPA receptors. Second, even in cortical neurons where the primary mechanism of toxicity appears to be activation of NMDA receptors, there are other mechanisms involved. We found that along with NMDA receptors, activation of mGLuR5 receptors and effects on the cystine/glutamate antiporter (system x c -) were involved in the toxicity. The effects on system x c - are of particular interest. System x c - mediates the transport of cystine into the cell in exchange for releasing glutamate into the extracellular fluid. By releasing glutamate, system x c - can potentially cause excitotoxicity. However, through providing cystine to the cell, it regulates the levels of cellular glutathione (GSH), the main endogenous intracellular antioxidant, and in this way may protect cells against oxidative stress. We have previously published that BMAA inhibits cystine uptake leading to GSH depletion and had indirect evidence that BMAA is transported into the cells by system x c -. We now present direct evidence that BMAA is transported into both astrocytes and neurons through system x c -. The fact that BMAA is transported by system x c - also provides a mechanism for BMAA to enter brain cells potentially leading to misincorporation into proteins and protein misfolding.

  14. Time-dependent current into and through multilevel parallel quantum dots in a photon cavity

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Vidar; Abdullah, Nzar Rauf; Sitek, Anna; Goan, Hsi-Sheng; Tang, Chi-Shung; Manolescu, Andrei

    2017-05-01

    We analyze theoretically the charging current into, and the transport current through, a nanoscale two-dimensional electron system with two parallel quantum dots embedded in a short wire placed in a photon cavity. A plunger gate is used to place specific many-body states of the interacting system in the bias window defined by the external leads. We show how the transport phenomena active in the many-level complex central system strongly depend on the gate voltage. We identify a resonant transport through the central system as the two spin components of the one-electron ground state are in the bias window. This resonant transport through the lowest energy electron states seems to a large extent independent of the detuned photon field when judged from the transport current. This could be expected in the small bias regime, but an observation of the occupancy of the states of the system reveals that this picture is not entirely true. The current does not reflect slower photon-active internal transitions bringing the system into the steady state. The number of initially present photons determines when the system reaches the real steady state. With two-electron states in the bias window we observe a more complex situation with intermediate radiative and nonradiative relaxation channels leading to a steady state with a weak nonresonant current caused by inelastic tunneling through the two-electron ground state of the system. The presence of the radiative channels makes this phenomena dependent on the number of photons initially in the cavity.

  15. Purified reconstituted lac carrier protein from Escherichia coli is fully functional.

    PubMed

    Viitanen, P; Garcia, M L; Kaback, H R

    1984-03-01

    Proteoliposomes reconstituted with lac carrier protein purified from the plasma membrane of Escherichia coli catalyze each of the translocation reactions typical of the beta-galactoside transport system (i.e., active transport, counterflow, facilitated influx and efflux) with turnover numbers and apparent Km values comparable to those observed in right-side-out membrane vesicles. Furthermore, detailed kinetic studies show that the reconstituted system exhibits properties analogous to those observed in membrane vesicles. Imposition of a membrane potential (delta psi, interior negative) causes a marked decrease in apparent Km (by a factor of 7 to 10) with a smaller increase in Vmax (approximately equal to 3-fold). At submaximal values of delta psi, the reconstituted carrier exhibits biphasic kinetics, with one component manifesting the kinetic parameters of active transport and the other exhibiting the characteristics of facilitated diffusion. Finally, at low lactose concentrations, the initial velocity of influx varies linearly with the square of the proton electro-chemical gradient. The results provide quantitative support for the contention that a single polypeptide species, the product of the lac y gene, is responsible for each of the transport reactions typical of the beta-galactoside transport system.

  16. [Lipoproteins as a specific circulatory transport system].

    PubMed

    Titov, V N

    1998-01-01

    In accordance with the systemic approach, each circulatory transport system is highly specific and transports an elementary substance from cell to cell in the hydrated medium. In the author's opinion, the lipoprotein system has also a functional specificity and carries the elementary substance fatty acid in the blood stream. A great variety of fatty acids, the individuality of their physicochemical properties, great stereochemic differences of saturated and polyenic fatty acids make their transport virtually impossible. The steric individuality of fatty acids can be reduced if the acids are covalently bonded by a matrix as complex lipids. For formation of complex lipids, nature prefers esterification of fatty acids with alcohols which have a varying hydrophoby, such as glycerol, sphingosine, cholesterol, cetyl alcohol. The steric differences of saturated and polyenic fatty acids form a basis for their being structurized in different lipids. Triacyl glycerides are a transport form of saturated, monounsaturated fatty acids and their transforms and give rise to a crystalline phase. Phospholipids and cholesterol esters are a transport form of mainly polyunsaturated fatty acids in the polar phase in the former case and in the crystalline phase in the latter one. The individual apolipoproteins structure complex lipids into individual lipoprotein particles and transport them in the hydrated medium of blood flow. Saturated fatty acids chiefly transport lipoprotein particles formed by apoB-48- and apoB-100-isoproteins. Polyenic acids transport mainly high-density apoA-1-lipoprotein particles, which makes up a main physiological function of the latter. Cholesterol is nothing more than a matrix; it reesterifies polyenic fatty acids from the polar transport form of phospholipids into the unpolar transport form of cholesterol esters. Cholesterol esterification of polyenic fatty acids may structure complex lipid in the unpolar phase and transport it to the cells via apoB-100-ligand-receptor interaction, which is considered to be a key stage in the multistage process of active transport to the cells of polyenic fatty acids. However, the significant differences of active and inactive transport of polyenic fatty acids in the blood stream await a separate consideration.

  17. Opposite temperature effect on transport activity of KCC2/KCC4 and N(K)CCs in HEK-293 cells.

    PubMed

    Hartmann, Anna-Maria; Nothwang, Hans Gerd

    2011-12-09

    Cation chloride cotransporters play essential roles in many physiological processes such as volume regulation, transepithelial salt transport and setting the intracellular chloride concentration in neurons. They consist mainly of the inward transporters NCC, NKCC1, and NKCC2, and the outward transporters KCC1 to KCC4. To gain insight into regulatory and structure-function relationships, precise determination of their activity is required. Frequently, these analyses are performed in HEK-293 cells. Recently the activity of the inward transporters NKCC1 and NCC was shown to increase with temperature in these cells. However, the temperature effect on KCCs remains largely unknown. Here, we determined the temperature effect on KCC2 and KCC4 transport activity in HEK-293 cells. Both transporters demonstrated significantly higher transport activity (2.5 fold for KCC2 and 3.3 fold for KCC4) after pre-incubation at room temperature compared to 37°C. These data identify a reciprocal temperature dependence of cation chloride inward and outward cotransporters in HEK-293 cells. Thus, lower temperature should be used for functional characterization of KCC2 and KCC4 and higher temperatures for N(K)CCs in heterologous mammalian expression systems. Furthermore, if this reciprocal effect also applies to neurons, the action of inhibitory neurotransmitters might be more affected by changes in temperature than previously thought.

  18. Distance from public transportation and physical activity in Japanese older adults: The moderating role of driving status.

    PubMed

    Harada, Kazuhiro; Lee, Sangyoon; Lee, Sungchul; Bae, Seongryu; Anan, Yuya; Harada, Kenji; Shimada, Hiroyuki

    2018-04-01

    Although previous studies have shown that good access to public transportation is positively related with physical activity, the moderators of this relationship have not been explored sufficiently in older adults. It is possible that driving status could moderate this relationship. The present study examined whether the objectively measured distance between public transportation and the home was associated with physical activity levels, and whether this association was moderated by driving status among Japanese older adults. In this cross-sectional study, participants (n = 2,878) completed questionnaires and wore accelerometers for at least 7 days, to measure their average daily step counts and minutes spent engaging in moderate-to-vigorous physical activity. Road network distances between the home and the nearest bus stop or train station were measured using geographic information systems. Driving status was assessed using questionnaires. Multiple regression analyses stratified by driving status revealed that, among nondrivers, living further away from public transportation was associated with higher step counts (β = 0.08, p < .001) and moderate-to-vigorous physical activity (β = 0.06, p = .029). Among drivers, living closer to public transportation was significantly associated with higher moderate-to-vigorous physical activity levels (β = -0.05, p = .042). Despite the small effect sizes, the direction of the association between distance from public transportation and physical activity was different for current drivers and nondrivers. These findings imply that good access to public transportation does not positively relate with greater engagement in physical activity among nondriving older adults. Shorter distances to public transportation might reduce opportunities for engaging in physical activity for them. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  19. Mitochondrial phenotype during torpor: Modulation of mitochondrial electron transport system in the Chilean mouse-opossum Thylamys elegans.

    PubMed

    Cortes, Pablo A; Bozinovic, Francisco; Blier, Pierre U

    2018-07-01

    Mammalian torpor is a phenotype characterized by a controlled decline of metabolic rate, generally followed by a reduction in body temperature. During arousal from torpor, both metabolic rate and body temperature rapidly returns to resting levels. Metabolic rate reduction experienced by torpid animals is triggered by active suppression of mitochondrial respiration, which is rapidly reversed during rewarming process. In this study, we analyzed the changes in the maximal activity of key enzymes related to electron transport system (complexes I, III and IV) in six tissues of torpid, arousing and euthermic Chilean mouse-opossums (Thylamys elegans). We observed higher maximal activities of complexes I and IV during torpor in brain, heart and liver, the most metabolically active organs in mammals. On the contrary, higher enzymatic activities of complexes III were observed during torpor in kidneys and lungs. Moreover, skeletal muscle was the only tissue without significant differences among stages in all complexes evaluated, suggesting no modulation of oxidative capacities of electron transport system components in this thermogenic tissue. In overall, our data suggest that complexes I and IV activity plays a major role in initiation and maintenance of metabolic suppression during torpor in Chilean mouse-opossum, whereas improvement of oxidative capacities in complex III might be critical to sustain metabolic machinery in organs that remains metabolically active during torpor. Copyright © 2018 Elsevier Inc. All rights reserved.

  20. VELoCiRaPTORS.

    NASA Astrophysics Data System (ADS)

    Lundgren, J.; Esham, B.; Padalino, S. J.; Sangster, T. C.; Glebov, V.

    2007-11-01

    The Venting and Exhausting of Low Level Air Contaminants in the Rapid Pneumatic Transport of Radioactive Samples (VELoCiRaPTORS) system is constructed to transport radioactive materials quickly and safely at the NIF. A radioactive sample will be placed inside a carrier that is transported via an airflow system produced by controlled differential pressure. Midway through the transportation process, the carrier will be stopped and vented by a powered exhaust blower which will remove radioactive gases within the transport carrier. A Geiger counter will monitor the activity of the exhaust gas to ensure that it is below acceptable levels. If the radiation level is sufficient, the carrier will pass through the remainder of the system, pneumatically braking at the counting station. The complete design will run manually or automatically with control software. Tests were performed using an inactive carrier to determine possible transportation problems. The system underwent many consecutive trials without failure. VELoCiRaPTORS is a prototype of a system that could be installed at both the Laboratory for Laser Energetics at the University of Rochester and the National Ignition Facility at LLNL.

  1. Alternative electron transports participate in the maintenance of violaxanthin De-epoxidase activity of Ulva sp. under low irradiance.

    PubMed

    Xie, Xiujun; Gu, Wenhui; Gao, Shan; Lu, Shan; Li, Jian; Pan, Guanghua; Wang, Guangce; Shen, Songdong

    2013-01-01

    The xanthophyll cycle (Xc), which involves violaxanthin de-epoxidase (VDE) and the zeaxanthin epoxidase (ZEP), is one of the most rapid and efficient responses of plant and algae to high irradiance. High light intensity can activate VDE to convert violaxanthin (Vx) to zeaxanthin (Zx) via antheraxanthin (Ax). However, it remains unclear whether VDE remains active under low light or dark conditions when there is no significant accumulation of Ax and Zx, and if so, how the ΔpH required for activation of VDE is built. In this study, we used salicylaldoxime (SA) to inhibit ZEP activity in the intertidal macro-algae Ulva sp. (Ulvales, Chlorophyta) and then characterized VDE under low light and dark conditions with various metabolic inhibitors. With inhibition of ZEP by SA, VDE remained active under low light and dark conditions, as indicated by large accumulations of Ax and Zx at the expense of Vx. When PSII-mediated linear electron transport systems were completely inhibited by SA and DCMU, alternative electron transport systems (i.e., cyclic electron transport and chlororespiration) could maintain VDE activity. Furthermore, accumulations of Ax and Zx decreased significantly when SA, DCMU, or DBMIB together with an inhibitor of chlororespiration (i.e., propyl gallate (PG)) were applied to Ulva sp. This result suggests that chlororespiration not only participates in the build-up of the necessary ΔpH, but that it also possibly influences VDE activity indirectly by diminishing the oxygen level in the chloroplast.

  2. Alternative Electron Transports Participate in the Maintenance of Violaxanthin De-Epoxidase Activity of Ulva sp. under Low Irradiance

    PubMed Central

    Xie, Xiujun; Gu, Wenhui; Gao, Shan; Lu, Shan; Li, Jian; Pan, Guanghua; Wang, Guangce; Shen, Songdong

    2013-01-01

    The xanthophyll cycle (Xc), which involves violaxanthin de-epoxidase (VDE) and the zeaxanthin epoxidase (ZEP), is one of the most rapid and efficient responses of plant and algae to high irradiance. High light intensity can activate VDE to convert violaxanthin (Vx) to zeaxanthin (Zx) via antheraxanthin (Ax). However, it remains unclear whether VDE remains active under low light or dark conditions when there is no significant accumulation of Ax and Zx, and if so, how the ΔpH required for activation of VDE is built. In this study, we used salicylaldoxime (SA) to inhibit ZEP activity in the intertidal macro-algae Ulva sp. (Ulvales, Chlorophyta) and then characterized VDE under low light and dark conditions with various metabolic inhibitors. With inhibition of ZEP by SA, VDE remained active under low light and dark conditions, as indicated by large accumulations of Ax and Zx at the expense of Vx. When PSII-mediated linear electron transport systems were completely inhibited by SA and DCMU, alternative electron transport systems (i.e., cyclic electron transport and chlororespiration) could maintain VDE activity. Furthermore, accumulations of Ax and Zx decreased significantly when SA, DCMU, or DBMIB together with an inhibitor of chlororespiration (i.e., propyl gallate (PG)) were applied to Ulva sp. This result suggests that chlororespiration not only participates in the build-up of the necessary ΔpH, but that it also possibly influences VDE activity indirectly by diminishing the oxygen level in the chloroplast. PMID:24250793

  3. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Program review

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This report summarizes the Integrated Application of Active Controls (IAAC) Technology to an Advanced Subsonic Transport Project, established as one element of the NASA/Boeing Energy Efficient Transport Technology Program. The performance assessment showed that incorporating ACT into an airplane designed to fly approximately 200 passengers approximately 2,000 nmi could yield block fuel savings from 6 to 10 percent at the design range. The principal risks associated with incorporating these active control functions into a commercial airplane are those involved with the ACT system implementation. The Test and Evaluation phase of the IAAC Project focused on the design, fabrication, and test of a system that implemented pitch axis fly-by-wire, pitch axis augmentation, and wing load alleviation. The system was built to be flight worthy, and was planned to be experimentally flown on the 757. The system was installed in the Boeing Digital Avionics Flight Controls Laboratory (DAFCL), where open loop hardware and software tests, and a brief examination of a direct drive valve (DDV) actuation concept were accomplished. The IAAC Project has shown that ACT can be beneficially incorporated into a commercial transport airplane. Based on the results achieved during the testing phase, there appears to be no fundamental reason(s) that would preclude the commercial application of ACT, assuming an appropriate development effort is included.

  4. Functional reconstitution of an ATP-driven Ca sup 2+ -transport system from the plasma membrane of Commelina communis L

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Graef, P.; Weiler, E.W.

    1990-10-01

    The protein(s) that constitute(s) the ATP-driven Ca{sup 2+}-translocator of plasma membrane enriched vesicles obtained by aqueous two-phase partitioning from leaves of Commelina communis L. has/have been solubilized and reincorporated into tightly sealed liposomes. The reconstituted Ca{sup 2+}-transport system was studied using ATP-driven {sup 45}Ca{sup 2+} import into the proteoliposomes as a measure of activity. The detergent, 3- ((3-cholamidopropyl) dimethylammonio) -1-propane-sulfonate proved to be the most suitable and was used at 10 millimolar concentration, i.e. just above its critical micellar concentration. The presence of additional phospholipid and ATP improved the solubilization and/or reconstitution. The characteristics of the reconstituted system were similarmore » to those of the plasma membrane-bound activity, including the apparent K{sub m} for Ca{sup 2+} inhibition by relatively high levels of vanadate and lacking response to added calmodulin. The reconstituted transport system was very strongly inhibited by erythrosine B and had a low apparent K{sub m} for ATP levels of the Ca{sup 2+}-ionophore A 23187 instantaneously discharged 90% of the Ca{sup 2+} associated with the vesicles, proving that it had been accumulated in the intravesicular volume in soluble, freely exchangeable form. Ca{sup 2+}-transport in the reconstituted system was thus primary active, through a Ca{sup 2+}-translocating ATPase.« less

  5. Transport and Application of Heat-Activated Persulfate for In-situ Chemical Oxidation of Residual Trichloroethylene

    NASA Astrophysics Data System (ADS)

    Quig, L.; Johnson, G. R.

    2015-12-01

    Persulfate ISCO has been shown to treat a wide range of contaminants. While persulfate ISCO can be tailored to site and pollutant specific characteristics (e.g., activation via energy or catalysis), thermal activation of persulfate is particularly promising as it can be easily controlled and requires no additional reagents. A mechanistic study of the physical and chemical processes controlling the effectiveness of this remedial approach is not well documented in the literature with much therein focused on reactions in batch systems. The purpose of this research was twofold. Initial studies characterized the overall transport behavior of unactivated and thermally-activated persulfate (20, 60, and 90°C) in one-dimensional soil column systems. Finally, experiments were conducted to investigate persulfate ISCO as a remedial approach for residual-phase trichloroethylene (TCE). At all activation temperatures investigated, persulfate exhibited ideal transport behavior in miscible displacement experiments. Moment analysis of persulfate ion breakthrough curves indicated negligible interaction of persulfate with the natural sandy material. Persulfate ISCO for residual-phase TCE was characterized at two flow rates, 0.2 mL/min and 0.5 mL/min, resulting in two degrees of persulfate activation, 39.5% and 24.6%, respectively. Both ISCO soil column systems showed an initial, long-term plateau in effluent TCE concentrations indicating steady-state dissolution of pure phase TCE. Observed effluent concentrations decreased after 75 and 100 pore volumes (normalized for the measured residual NAPL fraction) compared to 110 pore volumes in the control study. Pseudo first-order reaction rate constants for the decreasing TCE concentrations equaled 0.063/hr and 0.083/hr, respectively, compared to 0.041/hr for the control. Moment analysis of the complete dissolution of TCE in the persulfate/activated persulfate remediation systems indicated approximately 33% oxidation of TCE mass present. By characterizing the overall transport behavior and application of persulfate/heat-activated persulfate in a natural porous media for the ISCO of residual nonaqueous phase liquid, this work aids in improving the implementation of persulfate ISCO systems.

  6. Multimotor Transport in a System of Active and Inactive Kinesin-1 Motors

    PubMed Central

    Scharrel, Lara; Ma, Rui; Schneider, René; Jülicher, Frank; Diez, Stefan

    2014-01-01

    Long-range directional transport in cells is facilitated by microtubule-based motor proteins. One example is transport in a nerve cell, where small groups of motor proteins, such as kinesins and cytoplasmic dynein, work together to ensure the supply and clearance of cellular material along the axon. Defects in axonal transport have been linked to Alzheimer’s and other neurodegenerative diseases. However, it is not known in detail how multimotor-based cargo transport is impaired if a fraction of the motors are defective. To mimic impaired multimotor transport in vitro, we performed gliding motility assays with varying fractions of active kinesin-1 motors and inactive kinesin-1 motor mutants. We found that impaired transport manifests in multiple motility regimes: 1), a fast-motility regime characterized by gliding at velocities close to the single-molecule velocity of the active motors; 2), a slow-motility regime characterized by gliding at close-to zero velocity or full stopping; and 3), a regime in which fast and slow motilities coexist. Notably, the transition from the fast to the slow regime occurred sharply at a threshold fraction of active motors. Based on single-motor parameters, we developed a stochastic model and a mean-field theoretical description that explain our experimental findings. Our results demonstrate that impaired multimotor transport mostly occurs in an either/or fashion: depending on the ratio of active to inactive motors, transport is either performed at close to full speed or is out of action. PMID:25028878

  7. Artificial transmembrane ion channels from self-assembling peptide nanotubes

    NASA Astrophysics Data System (ADS)

    Ghadiri, M. Reza; Granja, Juan R.; Buehler, Lukas K.

    1994-05-01

    NATURALLY occurring membrane channels and pores are formed from a large family of diverse proteins, peptides and organic secon-dary metabolites whose vital biological functions include control of ion flow, signal transduction, molecular transport and produc-tion of cellular toxins. But despite the availability of a large amount of biochemical information about these molecules1, the design and synthesis of artificial systems that can mimic the bio-logical function of natural compounds remains a formidable task2-12. Here we present a simple strategy for the design of artifi-cial membrane ion channels based on a self-assembled cylindrical β-sheet peptide architecture13. Our systems-essentially stacks of peptide rings-display good channel-mediated ion-transport activ-ity with rates exceeding 107 ions s-1, rivalling the performance of many naturally occurring counterparts. Such molecular assemblies should find use in the design of novel cytotoxic agents, membrane transport vehicles and drug-delivery systems.

  8. A preliminary demonstration of "virtual warehousing" and cross-docking technique with active RFID combined with asset tracking equipment.

    DOT National Transportation Integrated Search

    2010-11-01

    The University of Denvers Intermodal Transportation Institute and System Planning : Corporations GlobalTrak system have successfully demonstrated the integration of GPS : tracking and active RFID monitoring of simulated cargo of pallet and cart...

  9. 77 FR 58616 - Pipeline Safety: Information Collection Activities, Revision to Gas Transmission and Gathering...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-21

    ... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration [Docket No. PHMSA-2012-0024] Pipeline Safety: Information Collection Activities, Revision to Gas Transmission and Gathering Pipeline Systems Annual Report, Gas Transmission and Gathering Pipeline Systems Incident Report...

  10. Integrating the transportation system with a university campus transportation master plan : a case study.

    DOT National Transportation Integrated Search

    2010-04-01

    University campuses are considered major trip attractors. This intense level of activity generates significant : congestion levels within the campuses and in their vicinity, particularly in urban campus settings. With : university enrollment trends e...

  11. Pre-Demonstration Activities of the Westport Integrated Transit System

    DOT National Transportation Integrated Search

    1977-07-01

    In August 1976 the Urban Mass Transportation Administration of the U.S. Department of Transportation awarded a demonstration grant to the Westport Transit District (WTD) to examine the feasibility of combining shared-ride taxi service and other parat...

  12. SNAT2 and LAT1 transporter abundance is developmentally regulated in skeletal muscle of neonatal pigs

    USDA-ARS?s Scientific Manuscript database

    Previously, we demonstrated that the insulin and amino acid–induced activation of the mammalian target of rapamycin complex 1 (mTORC1), is developmentally regulated in neonatal pigs. Recent studies have indicated an important role of the System A transporters (SNAT2 and SLC1A5) and the L transporter...

  13. Activation product transport in fusion reactors. [RAPTOR

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Klein, A.C.

    1983-01-01

    Activated corrosion and neutron sputtering products will enter the coolant and/or tritium breeding material of fusion reactor power plants and experiments and cause personnel access problems. Radiation levels around plant components due to these products will cause difficulties with maintenance and repair operations throughout the plant. Similar problems are experienced around fission reactor systems. The determination of the transport of radioactive corrosion and neutron sputtering products through the system is achieved using the computer code RAPTOR. This code calculates the mass transfer of a number of activation products based on the corrosion and sputtering rates through the system, the depositionmore » and release characteristics of various plant components, the neturon flux spectrum, as well as other plant parameters. RAPTOR assembles a system of first order linear differential equations into a matrix equation based upon the reactor system parameters. Included in the transfer matrix are the deposition and erosion coefficients, and the decay and activation data for the various plant nodes and radioactive isotopes. A source vector supplies the corrosion and neutron sputtering source rates. This matrix equation is then solved using a matrix operator technique to give the specific activity distribution of each radioactive species throughout the plant. Once the amount of mass transfer is determined, the photon transport due to the radioactive corrosion and sputtering product sources can be evaluated, and dose rates around the plant components of interest as a function of time can be determined. This method has been used to estimate the radiation hazards around a number of fusion reactor system designs.« less

  14. Ridesharing: Transportation demand management

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Valdez, R.; Wang, J.; Flynn, C.P.

    1989-01-01

    The 13 papers in the report deal with the following areas: Comparison of transportation demand management market research study results and transportation management association development in three suburban activity centers; Ten cities' strategies for transportation demand management; Key considerations for developing local government transportation system management programs; First Hill Action Plan: A unique public/private approach to transportation demand management; Comparison of travel behavior before and after the opening of HOV lanes in a suburban travel corridor; Evaluation of Springfield instant carpooling; George Washington Bridge bus-carpool lane: 1-Year Operational Report; Guaranteed Ride Home: An insurance program for HOV users; Evaluation ofmore » Ridefinders and Central Richmond Association's transportation and parking information service; Vanpools: Pricing and market penetration; Cost-effectiveness of private employer ridesharing programs: An employer's assessment; Temporal analysis of handicapped ridership in specialized transportation service: Lexington/Fayette County experience; Characterization of the 'publico' system of Puerto Rico.« less

  15. Cholinergic regulation of epithelial ion transport in the mammalian intestine

    PubMed Central

    Hirota, C L; McKay, D M

    2006-01-01

    Acetylcholine (ACh) is critical in controlling epithelial ion transport and hence water movements for gut hydration. Here we review the mechanism of cholinergic control of epithelial ion transport across the mammalian intestine. The cholinergic nervous system affects basal ion flux and can evoke increased active ion transport events. Most studies rely on measuring increases in short-circuit current (ISC = active ion transport) evoked by adding ACh or cholinomimetics to intestinal tissue mounted in Ussing chambers. Despite subtle species and gut regional differences, most data indicate that, under normal circumstances, the effect of ACh on intestinal ion transport is mainly an increase in Cl- secretion due to interaction with epithelial M3 muscarinic ACh receptors (mAChRs) and, to a lesser extent, neuronal M1 mAChRs; however, AChR pharmacology has been plagued by a lack of good receptor subtype-selective compounds. Mice lacking M3 mAChRs display intact cholinergically-mediated intestinal ion transport, suggesting a possible compensatory mechanism. Inflamed tissues often display perturbations in the enteric cholinergic system and reduced intestinal ion transport responses to cholinomimetics. The mechanism(s) underlying this hyporesponsiveness are not fully defined. Inflammation-evoked loss of mAChR-mediated control of epithelial ion transport in the mouse reveals a role for neuronal nicotinic AChRs, representing a hitherto unappreciated braking system to limit ACh-evoked Cl- secretion. We suggest that: i) pharmacological analyses should be supported by the use of more selective compounds and supplemented with molecular biology techniques targeting specific ACh receptors and signalling molecules, and ii) assessment of ion transport in normal tissue must be complemented with investigations of tissues from patients or animals with intestinal disease to reveal control mechanisms that may go undetected by focusing on healthy tissue only. PMID:16981004

  16. National space transportation studies

    NASA Technical Reports Server (NTRS)

    Durocher, Cort L.; Irby, Thomas M.; Jenkins, James C.; Gorski, Raymond J.

    1986-01-01

    This paper describes the government and industry activities and findings in response to a Presidential directive to study second-generation space transportation systems. Topics discussed include study purpose, mission needs, architecture development, system concepts, and technology recommendations. Interim study findings will also be presented. The study is being jointly managed by DOD and NASA and equally funded by DOD, NASA, and the Strategic Defense Initiative Organization.

  17. Frataxin Depletion in Yeast Triggers Up-regulation of Iron Transport Systems before Affecting Iron-Sulfur Enzyme Activities*

    PubMed Central

    Moreno-Cermeño, Armando; Obis, Èlia; Bellí, Gemma; Cabiscol, Elisa; Ros, Joaquim; Tamarit, Jordi

    2010-01-01

    The primary function of frataxin, a mitochondrial protein involved in iron homeostasis, remains controversial. Using a yeast model of conditional expression of the frataxin homologue YFH1, we analyzed the primary effects of YFH1 depletion. The main conclusion unambiguously points to the up-regulation of iron transport systems as a primary effect of YFH1 down-regulation. We observed that inactivation of aconitase, an iron-sulfur enzyme, occurs long after the iron uptake system has been activated. Decreased aconitase activity should be considered part of a group of secondary events promoted by iron overloading, which includes decreased superoxide dismutase activity and increased protein carbonyl formation. Impaired manganese uptake, which contributes to superoxide dismutase deficiency, has also been observed in YFH1-deficient cells. This low manganese content can be attributed to the down-regulation of the metal ion transporter Smf2. Low Smf2 levels were not observed in AFT1/YFH1 double mutants, indicating that high iron levels could be responsible for the Smf2 decline. In summary, the results presented here indicate that decreased iron-sulfur enzyme activities in YFH1-deficient cells are the consequence of the oxidative stress conditions suffered by these cells. PMID:20956517

  18. Toward Optimal Transport Networks

    NASA Technical Reports Server (NTRS)

    Alexandrov, Natalia; Kincaid, Rex K.; Vargo, Erik P.

    2008-01-01

    Strictly evolutionary approaches to improving the air transport system a highly complex network of interacting systems no longer suffice in the face of demand that is projected to double or triple in the near future. Thus evolutionary approaches should be augmented with active design methods. The ability to actively design, optimize and control a system presupposes the existence of predictive modeling and reasonably well-defined functional dependences between the controllable variables of the system and objective and constraint functions for optimization. Following recent advances in the studies of the effects of network topology structure on dynamics, we investigate the performance of dynamic processes on transport networks as a function of the first nontrivial eigenvalue of the network's Laplacian, which, in turn, is a function of the network s connectivity and modularity. The last two characteristics can be controlled and tuned via optimization. We consider design optimization problem formulations. We have developed a flexible simulation of network topology coupled with flows on the network for use as a platform for computational experiments.

  19. Pulmonary microsomes contain a Ca(2+)-transport system sensitive to oxidative stress.

    PubMed

    Menshikova, E V; Ritov, V B; Shvedova, A A; Elsayed, N; Karol, M H; Kagan, V E

    1995-03-14

    A variety of events, including inhalation of atmospheric chemicals, trauma, and ischemia-reperfusion, may cause generation of reactive oxygen species in the lung and result in airways constriction. The specific metabolic mechanisms that translate oxygen radical production into airways constriction are yet to be identified. In the lung, calcium homeostasis is central to release of bronchoactive and vasoactive chemical mediators and to regulation of smooth muscle cell contractility, i.e., airway constriction. In the present work, we characterized Ca(2+)-transport in the microsomal fraction of mouse lungs, and determined how reactive oxygen species, generated by Fe2+/ascorbate and H2O2/hemoglobin, affected Ca2+ transport. The microsomal fraction of pulmonary tissue accumulated 90 +/- 5 nmol Ca2+/mg protein by an ATP-dependent process in the presence of 15 mM oxalate, and 16 +/- 2 nmol Ca2+ in its absence. In the presence of oxalate, the rate of Ca2+ uptake was 50 +/- 5 nmol Ca2+/min per mg protein at pCa 5.9 (37 degrees C). The Ca(2+)-ATPase activity was 50-60 nmol Pi/min per mg protein (pCa 5.9, 37 degrees C) in the presence of alamethicin. Inhibitors of mitochondrial H(+)-ATPase had no effect on the Ca2+ transport. Half-maximal activation of Ca2+ transport was produced by 0.4-0.5 microM Ca2+. Endoplasmic reticulum Ca(2+)-pump (SERC-ATPase) was found to be predominantly responsible for the Ca(2+)-accumulating capacity of the pulmonary microsomes. Incubation of the microsomes in the presence of either Fe2+/ascorbate or H2O2/hemoglobin resulted in a time-dependent accumulation of peroxidation products (TBARS) and in inhibition of the Ca2+ transport. The inhibitory effect of Fe2+/ascorbate on Ca2+ transport strictly correlated with the inhibition of the Ca(2+)-ATPase activity. These results are the first to indicate a highly active microsomal Ca2+ transport system in murine lungs which is sensitive to endogenous oxidation products. The importance of this system to pulmonary disorders exacerbated by oxidative chemicals remains to be studied.

  20. Active controls for ride smoothing

    NASA Technical Reports Server (NTRS)

    Conner, D. W.; Thompson, G. O.

    1976-01-01

    Active controls technology offers great promise for significantly smoothing the ride, and thus improving public and air carrier acceptance, of certain types of transport aircraft. Recent findings which support this promise are presented in the following three pertinent areas: (1) Ride quality versus degree of traveler satisfaction; (2) significant findings from a feasibility study of a ride smoothing system; and (3) potential ride problems identified for several advanced transport concepts.

  1. The competitive advantage of a dual-transporter system.

    PubMed

    Levy, Sagi; Kafri, Moshe; Carmi, Miri; Barkai, Naama

    2011-12-09

    Cells use transporters of different affinities to regulate nutrient influx. When nutrients are depleted, low-affinity transporters are replaced by high-affinity ones. High-affinity transporters are helpful when concentrations of nutrients are low, but the advantage of reducing their abundance when nutrients are abundant is less clear. When we eliminated such reduced production of the Saccharomyces cerevisiae high-affinity transporters for phosphate and zinc, the elapsed time from the initiation of the starvation program until the lack of nutrients limited growth was shortened, and recovery from starvation was delayed. The latter phenotype was rescued by constitutive activation of the starvation program. Dual-transporter systems appear to prolong preparation for starvation and to facilitate subsequent recovery, which may optimize sensing of nutrient depletion by integrating internal and external information about nutrient availability.

  2. Walking associated with public transit: moving toward increased physical activity in the United States.

    PubMed

    Freeland, Amy L; Banerjee, Shailendra N; Dannenberg, Andrew L; Wendel, Arthur M

    2013-03-01

    We assessed changes in transit-associated walking in the United States from 2001 to 2009 and documented their importance to public health. We examined transit walk times using the National Household Travel Survey, a telephone survey administered by the US Department of Transportation to examine travel behavior in the United States. People are more likely to transit walk if they are from lower income households, are non-White, and live in large urban areas with access to rail systems. Transit walkers in large urban areas with a rail system were 72% more likely to transit walk 30 minutes or more per day than were those without a rail system. From 2001 to 2009, the estimated number of transit walkers rose from 7.5 million to 9.6 million (a 28% increase); those whose transit-associated walking time was 30 minutes or more increased from approximately 2.6 million to 3.4 million (a 31% increase). Transit walking contributes to meeting physical activity recommendations. Study results may contribute to transportation-related health impact assessment studies evaluating the impact of proposed transit systems on physical activity, potentially influencing transportation planning decisions.

  3. Transport delay compensation for computer-generated imagery systems

    NASA Technical Reports Server (NTRS)

    Mcfarland, Richard E.

    1988-01-01

    In the problem of pure transport delay in a low-pass system, a trade-off exists with respect to performance within and beyond a frequency bandwidth. When activity beyond the band is attenuated because of other considerations, this trade-off may be used to improve the performance within the band. Specifically, transport delay in computer-generated imagery systems is reduced to a manageable problem by recognizing frequency limits in vehicle activity and manual-control capacity. Based on these limits, a compensation algorithm has been developed for use in aircraft simulation at NASA Ames Research Center. For direct measurement of transport delays, a beam-splitter experiment is presented that accounts for the complete flight simulation environment. Values determined by this experiment are appropriate for use in the compensation algorithm. The algorithm extends the bandwidth of high-frequency flight simulation to well beyond that of normal pilot inputs. Within this bandwidth, the visual scene presentation manifests negligible gain distortion and phase lag. After a year of utilization, two minor exceptions to universal simulation applicability have been identified and subsequently resolved.

  4. 78 FR 44622 - Agency Information Collection; Activity Under OMB Review; Confidential Close Call Reporting System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

    ... (OMB) for approval for renewal of information collection supporting a multi-year research study that... DEPARTMENT OF TRANSPORTATION Research and Innovative Technology Administration Agency Information Collection; Activity Under OMB Review; Confidential Close Call Reporting System AGENCY: Research & Innovative...

  5. 78 FR 77484 - Extension of Agency Information Collection Activity Under OMB Review: Pipeline System Operator...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-23

    ... Federal agency for pipeline security, it is important for TSA to have contact information for company... DEPARTMENT OF HOMELAND SECURITY Transportation Security Administration Extension of Agency Information Collection Activity Under OMB Review: Pipeline System Operator Security Information AGENCY...

  6. Perinatal treatment of rats with opiates affects the development of the blood-brain barrier transport system PTS-1.

    PubMed

    Banks, W A; Kastin, A J; Harrison, L M; Zadina, J E

    1996-01-01

    Previous results have shown that treatment of rats with morphine during the neonatal period can influence development of peptide transport system-1 (PTS-1), the blood-brain barrier transport system for Tyr-MIF-1 and methionine enkephalin. Previous work has suggested that the activity level of PTS-1 correlates with the concentration of methionine enkephalin in the brain. We show here that rats treated peripherally with morphine sulfate (MS) in both the prenatal and neonatal periods have enhanced activity of PTS-1. The degree of enhancement increases with age to reach a 66% increase in comparison with controls at age 9 weeks. The mu agonist MS was more powerful than the kappa agonist ethylketocyclazocine (EKC) or the delta agonist [D-Pen2.5,pCl-Phe4]enkephalin (pCl-DPDPE) in producing this effect. Opiate antagonists had complex effects with methylnaltrexone blocking the action of MS on PTS-1. These results show that the level of PTS-1 activity in adult rats can be modified by perinatal events that affect opiate tone during development.

  7. Drones for aerodynamic and structural testing /DAST/ - A status report

    NASA Technical Reports Server (NTRS)

    Murrow, H. N.; Eckstrom, C. V.

    1978-01-01

    A program for providing research data on aerodynamic loads and active control systems on wings with supercritical airfoils in the transonic speed range is described. Analytical development, wind tunnel tests, and flight tests are included. A Firebee II target drone vehicle has been modified for use as a flight test facility. The program currently includes flight experiments on two aeroelastic research wings. The primary purpose of the first flight experiment is to demonstrate an active control system for flutter suppression on a transport-type wing. Design and fabrication of the wing are complete and after installing research instrumentation and the flutter suppression system, flight testing is expected to begin in early 1979. The experiment on the second research wing - a fuel-conservative transport type - is to demonstrate multiple active control systems including flutter suppression, maneuver load alleviation, gust load alleviation, and reduce static stability. Of special importance for this second experiment is the development and validation of integrated design methods which include the benefits of active controls in the structural design.

  8. Stoichiometry for binding and transport by the twin arginine translocation system.

    PubMed

    Celedon, Jose M; Cline, Kenneth

    2012-05-14

    Twin arginine translocation (Tat) systems transport large folded proteins across sealed membranes. Tat systems accomplish this feat with three membrane components organized in two complexes. In thylakoid membranes, cpTatC and Hcf106 comprise a large receptor complex containing an estimated eight cpTatC-Hcf106 pairs. Protein transport occurs when Tha4 joins the receptor complex as an oligomer of uncertain size that is thought to form the protein-conducting structure. Here, binding analyses with intact membranes or purified complexes indicate that each receptor complex could bind eight precursor proteins. Kinetic analysis of translocation showed that each precursor-bound site was independently functional for transport, and, with sufficient Tha4, all sites were concurrently active for transport. Tha4 titration determined that ∼26 Tha4 protomers were required for transport of each OE17 (oxygen-evolving complex subunit of 17 kD) precursor protein. Our results suggest that, when fully saturated with precursor proteins and Tha4, the Tat translocase is an ∼2.2-megadalton complex that can individually transport eight precursor proteins or cooperatively transport multimeric precursors.

  9. Water and Carbon Footprints for Sustainability Analysis of Urban Infrastructure

    EPA Science Inventory

    Water and transportation infrastructures define spatial distribution of urban population and economic activities. In this context, energy and water consumed per capita are tangible measures of how efficient water and transportation systems are constructed and operated. At a hig...

  10. Technology in rural transportation. Simple solution #10, wireless pagers to activate warning beacons

    DOT National Transportation Integrated Search

    1997-01-01

    This application was identified as a promising rural Intelligent Transportation Systems (ITS) solution under a project sponsored by the Federal Highway Administration (FHWA) and the ENTERPRISE program. This summary describes the solution as well as o...

  11. Demystifying Mag-Lev.

    ERIC Educational Resources Information Center

    Ruiz, Ernest; And Others

    1991-01-01

    Presented are classroom activities in which students explore the potential use of magnetic levitation for transportation purposes. The advantages of using a MagLev transportation system instead of conventional trains are discussed. Directions for designing and building a MagLev track and circuit are provided. (KR)

  12. The discovery of slowness: low-capacity transport and slow anion channel gating by the glutamate transporter EAAT5.

    PubMed

    Gameiro, Armanda; Braams, Simona; Rauen, Thomas; Grewer, Christof

    2011-06-08

    Excitatory amino acid transporters (EAATs) control the glutamate concentration in the synaptic cleft by glial and neuronal glutamate uptake. Uphill glutamate transport is achieved by the co-/countertransport of Na(+) and other ions down their concentration gradients. Glutamate transporters also display an anion conductance that is activated by the binding of Na(+) and glutamate but is not thermodynamically coupled to the transport process. Of the five known glutamate transporter subtypes, the retina-specific subtype EAAT5 has the largest conductance relative to glutamate uptake activity. Our results suggest that EAAT5 behaves as a slow-gated anion channel with little glutamate transport activity. At steady state, EAAT5 was activated by glutamate, with a K(m)= 61 ± 11 μM. Binding of Na(+) to the empty transporter is associated with a K(m) = 229 ± 37 mM, and binding to the glutamate-bound form is associated with a K(m) = 76 ± 40 mM. Using laser-pulse photolysis of caged glutamate, we determined the pre-steady-state kinetics of the glutamate-induced anion current of EAAT5. This was characterized by two exponential components with time constants of 30 ± 1 ms and 200 ± 15 ms, which is an order of magnitude slower than those observed in other glutamate transporters. A voltage-jump analysis of the anion currents indicates that the slow activation behavior is caused by two slow, rate-limiting steps in the transport cycle, Na(+) binding to the empty transporter, and translocation of the fully loaded transporter. We propose a kinetic transport scheme that includes these two slow steps and can account for the experimentally observed data. Overall, our results suggest that EAAT5 may not act as a classical high-capacity glutamate transporter in the retina; rather, it may function as a slow-gated glutamate receptor and/or glutamate buffering system. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  13. One-dimensional potential of mean force underestimates activation barrier for transport across flexible lipid membranes

    NASA Astrophysics Data System (ADS)

    Kopelevich, Dmitry I.

    2013-10-01

    Transport of a fullerene-like nanoparticle across a lipid bilayer is investigated by coarse-grained molecular dynamics (MD) simulations. Potentials of mean force (PMF) acting on the nanoparticle in a flexible bilayer suspended in water and a bilayer restrained to a flat surface are computed by constrained MD simulations. The rate of the nanoparticle transport into the bilayer interior is predicted using one-dimensional Langevin models based on these PMFs. The predictions are compared with the transport rates obtained from a series of direct (unconstrained) MD simulations of the solute transport into the flexible bilayer. It is observed that the PMF acting on the solute in the flexible membrane underestimates the transport rate by more than an order of magnitude while the PMF acting on the solute in the restrained membrane yields an accurate estimate of the activation energy for transport into the flexible membrane. This paradox is explained by a coexistence of metastable membrane configurations for a range of the solute positions inside and near the flexible membrane. This leads to a significant reduction of the contribution of the transition state to the mean force acting on the solute. Restraining the membrane shape ensures that there is only one stable membrane configuration corresponding to each solute position and thus the transition state is adequately represented in the PMF. This mechanism is quite general and thus this phenomenon is expected to occur in a wide range of interfacial systems. A simple model for the free energy landscape of the coupled solute-membrane system is proposed and validated. This model explicitly accounts for effects of the membrane deformations on the solute transport and yields an accurate prediction of the activation energy for the solute transport.

  14. Evaluation of advanced propulsion options for the next manned transportation system: Propulsion evolution study

    NASA Technical Reports Server (NTRS)

    Spears, L. T.; Kramer, R. D.

    1990-01-01

    The objectives were to examine launch vehicle applications and propulsion requirements for potential future manned space transportation systems and to support planning toward the evolution of Space Shuttle Main Engine (SSME) and Space Transportation Main Engine (STME) engines beyond their current or initial launch vehicle applications. As a basis for examinations of potential future manned launch vehicle applications, we used three classes of manned space transportation concepts currently under study: Space Transportation System Evolution, Personal Launch System (PLS), and Advanced Manned Launch System (AMLS). Tasks included studies of launch vehicle applications and requirements for hydrogen-oxygen rocket engines; the development of suggestions for STME engine evolution beyond the mid-1990's; the development of suggestions for STME evolution beyond the Advanced Launch System (ALS) application; the study of booster propulsion options, including LOX-Hydrocarbon options; the analysis of the prospects and requirements for utilization of a single engine configuration over the full range of vehicle applications, including manned vehicles plus ALS and Shuttle C; and a brief review of on-going and planned LOX-Hydrogen propulsion technology activities.

  15. Synthetic cathinone MDPV downregulates glutamate transporter subtype I (GLT-1) and produces rewarding and locomotor-activating effects that are reduced by a GLT-1 activator

    PubMed Central

    Gregg, Ryan A.; Hicks, Callum; Nayak, Sunil U.; Tallarida, Christopher S.; Nucero, Paul; Reitz, Allen B.; Smith, Garry R.; Rawls, Scott M.

    2016-01-01

    Synthetic cathinones produce dysregulation of monoamine systems, but their effects on the glutamate system and the influence of glutamate on behavioral effects related to cathinone abuse are unknown. A principal regulator of glutamate homeostasis is glutamate transporter subtype 1 (GLT-1), an astrocytic protein that clears glutamate from the extracellular space and influences behavioral effects of established psychostimulants. We hypothesized that repeated administration of the synthetic cathinone, MDPV (3,4-methylenedioxypyrovalerone), would affect GLT-1 expression in the corticolimbic circuit, and that a GLT-1 activator (ceftriaxone, CTX) would reduce rewarding and locomotor-stimulant effects of MDPV in rats. GLT-1 protein expression in the nucleus accumbens (NAcc), but not prefrontal cortex (PFC), was decreased following withdrawal (2, 5 and 10 days) from repeated MDPV treatment, but not immediately after the last MDPV injection. CTX (200 mg/kg) pretreatment did not affect acute locomotor activation produced by MDPV (0.5, 1, 3 mg/kg). However, CTX (200 mg/kg) administered during a 7-day MDPV treatment paradigm attenuated the development of MDPV-induced sensitization of repetitive movements in rats challenged with MDPV following 11 days of drug abstinence. Pretreatment with CTX (200 mg/kg) during a 4-day MDPV (2 mg/kg) conditioned place preference (CPP) paradigm reduced the development of place preference produced by MDPV. The present data demonstrate dysregulation of corticolimbic glutamate transport systems during withdrawal from chronic MDPV exposure, and show that a GLT-1 transporter activator disrupts behavioral effects of MDPV that are related to synthetic cathinone abuse. PMID:27085607

  16. Commercial vehicle information systems and networks (CVISN) glossary : baseline version

    DOT National Transportation Integrated Search

    1999-01-01

    This document defines terms and acronyms used in current Commercial Vehicle Information Systems and Networks (CVISN) documents and used in activities relevant to development of a national Intelligent Transportation System (ITS) system architecture fo...

  17. Commercial vehicle information systems and networks (CVISN) glossary : preliminary issue

    DOT National Transportation Integrated Search

    1996-10-01

    This document defines terms and acronyms used in current Commercial Vehicle Information Systems and Networks (CVISN) documents and used in activities relevant to development of a national Intelligent Transportation System (ITS) system architecture fo...

  18. Toxin activity assays, devices, methods and systems therefor

    DOEpatents

    Koh, Chung-Yan; Schaff, Ulrich Y.; Sommer, Gregory Jon

    2016-04-05

    Embodiments of the present invention are directed toward devices, system and method for conducting toxin activity assay using sedimentation. The toxin activity assay may include generating complexes which bind to a plurality of beads in a fluid sample. The complexes may include a target toxin and a labeling agent, or may be generated due to presence of active target toxin and/or labeling agent designed to be incorporated into complexes responsive to the presence of target active toxin. The plurality of beads including the complexes may be transported through a density media, wherein the density media has a lower density than a density of the beads and higher than a density of the fluid sample, and wherein the transporting occurs, at least in part, by sedimentation. Signal may be detected from the labeling agents of the complexes.

  19. Insulin-sensitive phospholipid signaling systems and glucose transport. Update II.

    PubMed

    Farese, R V

    2001-04-01

    Insulin provokes rapid changes in phospholipid metabolism and thereby generates biologically active lipids that serve as intracellular signaling factors that regulate glucose transport and glycogen synthesis. These changes include: (i) activation of phosphatidylinositol 3-kinase (PI3K) and production of PIP3; (ii) PIP3-dependent activation of atypical protein kinase Cs (PKCs); (iii) PIP3-dependent activation of PKB; (iv) PI3K-dependent activation of phospholipase D and hydrolysis of phosphatidylcholine with subsequent increases in phosphatidic acid (PA) and diacylglycerol (DAG); (v) PI3K-independent activation of glycerol-3-phosphate acylytansferase and increases in de novo synthesis of PA and DAG; and (vi) activation of DAG-sensitive PKCs. Recent findings suggest that atypical PKCs and PKB serve as important positive regulators of insulin-stimulated glucose metabolism, whereas mechanisms that result in the activation of DAG-sensitive PKCs serve mainly as negative regulators of insulin signaling through PI3K. Atypical PKCs and PKB are rapidly activated by insulin in adipocytes, liver, skeletal muscles, and other cell types by a mechanism requiring PI3K and its downstream effector, 3-phosphoinositide-dependent protein kinase-1 (PDK-1), which, in conjunction with PIP3, phosphorylates critical threonine residues in the activation loops of atypical PKCs and PKB. PIP3 also promotes increases in autophosphorylation and allosteric activation of atypical PKCs. Atypical PKCs and perhaps PKB appear to be required for insulin-induced translocation of the GLUT 4 glucose transporter to the plasma membrane and subsequent glucose transport. PKB also appears to be the major regulator of glycogen synthase. Together, atypical PKCs and PKB serve as a potent, integrated PI3K/PDK-1-directed signaling system that is used by insulin to regulate glucose metabolism.

  20. Aeronautical fuel conservation possibilities for advanced subsonic transports. [application of aeronautical technology for drag and weight reduction

    NASA Technical Reports Server (NTRS)

    Braslow, A. L.; Whitehead, A. H., Jr.

    1973-01-01

    The anticipated growth of air transportation is in danger of being constrained by increased prices and insecure sources of petroleum-based fuel. Fuel-conservation possibilities attainable through the application of advances in aeronautical technology to aircraft design are identified with the intent of stimulating NASA R and T and systems-study activities in the various disciplinary areas. The material includes drag reduction; weight reduction; increased efficiency of main and auxiliary power systems; unconventional air transport of cargo; and operational changes.

  1. Design and Development of Instructional Modules for Transportation Education and Development and Evaluation of Diffusion and Adoption Plan. Final Report.

    ERIC Educational Resources Information Center

    DeVore, Paul W.

    The background and objectives of the 1985-1986 Transportation Education Project of the Urban Mass Transportation Agency (UMTA) are discussed, along with project activities. The project was undertaken to transfer knowledge gained from federally-sponsored research and demonstrations to transit systems and to include the knowledge in college courses…

  2. Transportation research : the Department of Transportation has made progress in coordinating and reviewing its research activities : testimony before the Subcommittee on Technology and Innovation, Committee on Science and Technology, House of Representatives

    DOT National Transportation Integrated Search

    2009-02-12

    The FAST-TRAC (Faster and Safer Travel through Traffic Routing and Advanced Controls) Operational Field Test (OFT) is an Intelligent Transportation Systems (ITS) project being conducted in Southeast Michigan, managed by the Road Commission of Oakland...

  3. Active transport improves the precision of linear long distance molecular signalling

    NASA Astrophysics Data System (ADS)

    Godec, Aljaž; Metzler, Ralf

    2016-09-01

    Molecular signalling in living cells occurs at low copy numbers and is thereby inherently limited by the noise imposed by thermal diffusion. The precision at which biochemical receptors can count signalling molecules is intimately related to the noise correlation time. In addition to passive thermal diffusion, messenger RNA and vesicle-engulfed signalling molecules can transiently bind to molecular motors and are actively transported across biological cells. Active transport is most beneficial when trafficking occurs over large distances, for instance up to the order of 1 metre in neurons. Here we explain how intermittent active transport allows for faster equilibration upon a change in concentration triggered by biochemical stimuli. Moreover, we show how intermittent active excursions induce qualitative changes in the noise in effectively one-dimensional systems such as dendrites. Thereby they allow for significantly improved signalling precision in the sense of a smaller relative deviation in the concentration read-out by the receptor. On the basis of linear response theory we derive the exact mean field precision limit for counting actively transported molecules. We explain how intermittent active excursions disrupt the recurrence in the molecular motion, thereby facilitating improved signalling accuracy. Our results provide a deeper understanding of how recurrence affects molecular signalling precision in biological cells and novel medical-diagnostic devices.

  4. Inositol trisphosphate modification of ion transport in rough endoplasmic reticulum.

    PubMed

    Muallem, S; Schoeffield, M; Pandol, S; Sachs, G

    1985-07-01

    The ion transport properties of the rough endoplasmic reticulum (RER) from liver have been defined by using measurements of active and potential gradient-driven transport. The Ca2+ pump is shown to be electrogenic, and both ATP and potential difference is able to drive vanadate-inhibitable Ca2+ uptake into the RER. ATP-dependent Ca2+ transport into the RER depends on the presence of tetraethylammonium-sensitive cation conductance and a furosemide-inhibited cation/chloride cotransport pathway. Inositol trisphosphate does not affect either of the monovalent ion translocation systems but activates a Ca2+ conductance in the RER, allowing efflux of RER Ca2+ stores into the cytosol in exchange for K+ uptake.

  5. Inositol trisphosphate modification of ion transport in rough endoplasmic reticulum.

    PubMed Central

    Muallem, S; Schoeffield, M; Pandol, S; Sachs, G

    1985-01-01

    The ion transport properties of the rough endoplasmic reticulum (RER) from liver have been defined by using measurements of active and potential gradient-driven transport. The Ca2+ pump is shown to be electrogenic, and both ATP and potential difference is able to drive vanadate-inhibitable Ca2+ uptake into the RER. ATP-dependent Ca2+ transport into the RER depends on the presence of tetraethylammonium-sensitive cation conductance and a furosemide-inhibited cation/chloride cotransport pathway. Inositol trisphosphate does not affect either of the monovalent ion translocation systems but activates a Ca2+ conductance in the RER, allowing efflux of RER Ca2+ stores into the cytosol in exchange for K+ uptake. PMID:3874400

  6. Exploring the impact of walk–bike infrastructure, safety perception, and built-environment on active transportation mode choice: a random parameter model using New York City commuter data

    DOE PAGES

    Aziz, H. M. Abdul; Nagle, Nicholas N.; Morton, April M.; ...

    2017-02-06

    Here, this study finds the effects of traffic safety, walk-bike network facilities, and land use attributes on walk and bicycle mode choice decision in the New York City for home-to-work commute. Applying the flexible econometric structure of random parameter models, we capture the heterogeneity in the decision making process and simulate scenarios considering improvement in walk-bike infrastructure such as sidewalk width and length of bike lane. Our results indicate that increasing sidewalk width, total length of bike lane, and proportion of protected bike lane will increase the likelihood of more people taking active transportation mode This suggests that the localmore » authorities and planning agencies to invest more on building and maintaining the infrastructure for pedestrians. Furthermore, improvement in traffic safety by reducing traffic crashes involving pedestrians and bicyclists will increase the likelihood of taking active transportation modes. Our results also show positive correlation between number of non-motorized trips by the other family members and the likelihood to choose active transportation mode. The findings will help to make smart investment decisions in context of building sustainable transportation systems accounting for active transportation.« less

  7. Exploring the impact of walk–bike infrastructure, safety perception, and built-environment on active transportation mode choice: a random parameter model using New York City commuter data

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aziz, H. M. Abdul; Nagle, Nicholas N.; Morton, April M.

    Here, this study finds the effects of traffic safety, walk-bike network facilities, and land use attributes on walk and bicycle mode choice decision in the New York City for home-to-work commute. Applying the flexible econometric structure of random parameter models, we capture the heterogeneity in the decision making process and simulate scenarios considering improvement in walk-bike infrastructure such as sidewalk width and length of bike lane. Our results indicate that increasing sidewalk width, total length of bike lane, and proportion of protected bike lane will increase the likelihood of more people taking active transportation mode This suggests that the localmore » authorities and planning agencies to invest more on building and maintaining the infrastructure for pedestrians. Furthermore, improvement in traffic safety by reducing traffic crashes involving pedestrians and bicyclists will increase the likelihood of taking active transportation modes. Our results also show positive correlation between number of non-motorized trips by the other family members and the likelihood to choose active transportation mode. The findings will help to make smart investment decisions in context of building sustainable transportation systems accounting for active transportation.« less

  8. The Type VI Secretion System Engages a Redox-Regulated Dual-Functional Heme Transporter for Zinc Acquisition.

    PubMed

    Si, Meiru; Wang, Yao; Zhang, Bing; Zhao, Chao; Kang, Yiwen; Bai, Haonan; Wei, Dawei; Zhu, Lingfang; Zhang, Lei; Dong, Tao G; Shen, Xihui

    2017-07-25

    The type VI secretion system was recently reported to be involved in zinc acquisition, but the underlying mechanism remains unclear. Here, we report that Burkholderia thailandensis T6SS4 is involved in zinc acquisition via secretion of a zinc-scavenging protein, TseZ, that interacts with the outer membrane heme transporter HmuR. We find that HmuR is a redox-regulated dual-functional transporter that transports heme iron under normal conditions but zinc upon sensing extracellular oxidative stress, triggered by formation of an intramolecular disulfide bond. Acting as the first line of defense against oxidative stress, HmuR not only guarantees an immediate response to the changing environment but also provides a fine-tuned mechanism that allows a gradual response to perceived stress. The T6SS/HmuR-mediated active zinc transport system is also involved in bacterial virulence and contact-independent bacterial competition. We describe a sophisticated bacterial zinc acquisition mechanism affording insights into the role of metal ion transport systems. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  9. Water and Carbon Footprints for Sustainability Analysis of Urban Infrastructure - abstract

    EPA Science Inventory

    Water and transportation infrastructures define spatial distribution of urban population and economic activities. In this context, energy and water consumed per capita are tangible measures of how efficient water and transportation systems are constructed and operated. At a hig...

  10. Evidence of Two Functionally Distinct Ornithine Decarboxylation Systems in Lactic Acid Bacteria

    PubMed Central

    Romano, Andrea; Trip, Hein; Lonvaud-Funel, Aline; Lolkema, Juke S.

    2012-01-01

    Biogenic amines are low-molecular-weight organic bases whose presence in food can result in health problems. The biosynthesis of biogenic amines in fermented foods mostly proceeds through amino acid decarboxylation carried out by lactic acid bacteria (LAB), but not all systems leading to biogenic amine production by LAB have been thoroughly characterized. Here, putative ornithine decarboxylation pathways consisting of a putative ornithine decarboxylase and an amino acid transporter were identified in LAB by strain collection screening and database searches. The decarboxylases were produced in heterologous hosts and purified and characterized in vitro, whereas transporters were heterologously expressed in Lactococcus lactis and functionally characterized in vivo. Amino acid decarboxylation by whole cells of the original hosts was determined as well. We concluded that two distinct types of ornithine decarboxylation systems exist in LAB. One is composed of an ornithine decarboxylase coupled to an ornithine/putrescine transmembrane exchanger. Their combined activities results in the extracellular release of putrescine. This typical amino acid decarboxylation system is present in only a few LAB strains and may contribute to metabolic energy production and/or pH homeostasis. The second system is widespread among LAB. It is composed of a decarboxylase active on ornithine and l-2,4-diaminobutyric acid (DABA) and a transporter that mediates unidirectional transport of ornithine into the cytoplasm. Diamines that result from this second system are retained within the cytosol. PMID:22247134

  11. Objective and subjective measures of neighborhood environment (NE): relationships with transportation physical activity among older persons.

    PubMed

    Nyunt, Ma Shwe Zin; Shuvo, Faysal Kabir; Eng, Jia Yen; Yap, Keng Bee; Scherer, Samuel; Hee, Li Min; Chan, Siew Pang; Ng, Tze Pin

    2015-09-15

    This study examined the associations of subjective and objective measures of the neighbourhood environment with the transportation physical activity of community-dwelling older persons in Singapore. A modified version of the Neighborhood Environment Walkability Scale (NEWS) and Geographical Information System (GIS) measures of the built environment characteristics were related to the frequency of walking for transportation purpose in a study sample of older persons living in high-density apartment blocks within a public housing estate in Singapore. Relevant measured variables to assess the complex relationships among built environment measures and transportation physical activity were examined using structural equation modelling and multiple regression analyses. The subjective measures of residential density, street connectivity, land use mix diversity and aesthetic environment and the objective GIS measure of Accessibility Index have positively significant independent associations with transportation physical activity, after adjusting for demographics, socio-economic and health status. Subjective and objective measures are non-overlapping measures complementing each other in providing information on built environment characteristics. For elderly living in a high-density urban neighborhood, well connected street, diversity of land use mix, close proximity to amenities and facilities, and aesthetic environment were associated with higher frequency of walking for transportation purposes.

  12. Flight elements: Advanced avionics systems architectures

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Space transportation objectives are associated with transporting material from Earth to orbit, interplanetary travel, and planetary landing. The objectives considered herein are associated with Earth to orbit transportation. Many good avionics architectural features will support all phases of space transportation, but interplanetary transportation poses significantly different problems such as long mission time with high reliability, unattended operation, and many different opportunities such as long nonoperational flight segments that can be used for equipment fault diagnosis and repair. Fault tolerance can be used to permit continued operation with faulty units, not only during launch but also, and perhaps with more impact, during prelaunch activities. Avionics systems are entering a phase of development where the traditional approaches to satisfactory systems based on engineering judgement and thorough testing will alone no longer be adequate to assure that the required system performance can be obtained. A deeper understanding will be required to make the effects of obscure design decisions clear at a level where their impact can be properly judged.

  13. Extravehicular Activity Probabilistic Risk Assessment Overview for Thermal Protection System Repair on the Hubble Space Telescope Servicing Mission

    NASA Technical Reports Server (NTRS)

    Bigler, Mark; Canga, Michael A.; Duncan, Gary

    2010-01-01

    The Shuttle Program initiated an Extravehicular Activity (EVA) Probabilistic Risk Assessment (PRA) to assess the risks associated with performing a Shuttle Thermal Protection System (TPS) repair during the Space Transportation System (STS)-125 Hubble repair mission as part of risk trades between TPS repair and crew rescue.

  14. Sucrose-Metabolizing Enzymes in Transport Tissues and Adjacent Sink Structures in Developing Citrus Fruit 1

    PubMed Central

    Lowell, Cadance A.; Tomlinson, Patricia T.; Koch, Karen E.

    1989-01-01

    Juice tissues of citrus lack phloem; therefore, photosynthates enroute to juice sacs exit the vascular system on the surface of each segment. Areas of extensive phloem unloading and transport (vascular bundles + segment epidermis) can thus be separated from those of assimilate storage (juice sacs) and adjacent tissues where both processes occur (peel). Sugar composition, dry weight accumulation, and activities of four sucrose-metabolizing enzymes (soluble and cell-wall-bound acid invertase, alkaline invertase, sucrose synthase, and sucrose phosphate synthase) were measured in these transport and sink tissues of grapefruit (Citrus paradisi Macf.) to determine more clearly whether a given enzyme appeared to be more directly associated with assimilate transport versus deposition or utilization. Results were compared at three developmental stages. Activity of sucrose (per gram fresh weight and per milligram protein) extracted from zones of extensive phloem unloading and transport was significantly greater than from adjacent sink tissues during the stages (II and III) when juice sacs grow most rapidly. In stage II fruit, activity of sucrose synthase also significantly surpassed that of all other sucrose-metabolizing enzymes in extracts from the transport tissues (vascular bundles + segment epidermis). In contrast, sucrose phosphate synthase and alkaline invertase at this stage of growth were the most active enzymes from adjacent, rapidly growing, phloem-free sink tissues (juice sacs). Activity of these two enzymes in extracts from juice sacs was significantly greater than that form the transport tissues (vascular bundles + segment epidermis). Soluble acid invertase was the most active enzyme in extracts from all tissues of very young fruit (stage I), including nonvascular regions, but nearly disappeared prior to the onset of juice sac sugar accumulation. The physiological function of high sucrose synthase activity in the transport tissues during rapid sucrose import remains to be determined. PMID:16666942

  15. Analysis of Radiation Transport Due to Activated Coolant in the ITER Neutral Beam Injection Cell

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Royston, Katherine; Wilson, Stephen C.; Risner, Joel M.

    Detailed spatial distributions of the biological dose rate due to a variety of sources are required for the design of the ITER tokamak facility to ensure that all radiological zoning limits are met. During operation, water in the Integrated loop of Blanket, Edge-localized mode and vertical stabilization coils, and Divertor (IBED) cooling system will be activated by plasma neutrons and will flow out of the bioshield through a complex system of pipes and heat exchangers. This paper discusses the methods used to characterize the biological dose rate outside the tokamak complex due to 16N gamma radiation emitted by the activatedmore » coolant in the Neutral Beam Injection (NBI) cell of the tokamak building. Activated coolant will enter the NBI cell through the IBED Primary Heat Transfer System (PHTS), and the NBI PHTS will also become activated due to radiation streaming through the NBI system. To properly characterize these gamma sources, the production of 16N, the decay of 16N, and the flow of activated water through the coolant loops were modeled. The impact of conservative approximations on the solution was also examined. Once the source due to activated coolant was calculated, the resulting biological dose rate outside the north wall of the NBI cell was determined through the use of sophisticated variance reduction techniques. The AutomateD VAriaNce reducTion Generator (ADVANTG) software implements methods developed specifically to provide highly effective variance reduction for complex radiation transport simulations such as those encountered with ITER. Using ADVANTG with the Monte Carlo N-particle (MCNP) radiation transport code, radiation responses were calculated on a fine spatial mesh with a high degree of statistical accuracy. In conclusion, advanced visualization tools were also developed and used to determine pipe cell connectivity, to facilitate model checking, and to post-process the transport simulation results.« less

  16. Analysis of Radiation Transport Due to Activated Coolant in the ITER Neutral Beam Injection Cell

    DOE PAGES

    Royston, Katherine; Wilson, Stephen C.; Risner, Joel M.; ...

    2017-07-26

    Detailed spatial distributions of the biological dose rate due to a variety of sources are required for the design of the ITER tokamak facility to ensure that all radiological zoning limits are met. During operation, water in the Integrated loop of Blanket, Edge-localized mode and vertical stabilization coils, and Divertor (IBED) cooling system will be activated by plasma neutrons and will flow out of the bioshield through a complex system of pipes and heat exchangers. This paper discusses the methods used to characterize the biological dose rate outside the tokamak complex due to 16N gamma radiation emitted by the activatedmore » coolant in the Neutral Beam Injection (NBI) cell of the tokamak building. Activated coolant will enter the NBI cell through the IBED Primary Heat Transfer System (PHTS), and the NBI PHTS will also become activated due to radiation streaming through the NBI system. To properly characterize these gamma sources, the production of 16N, the decay of 16N, and the flow of activated water through the coolant loops were modeled. The impact of conservative approximations on the solution was also examined. Once the source due to activated coolant was calculated, the resulting biological dose rate outside the north wall of the NBI cell was determined through the use of sophisticated variance reduction techniques. The AutomateD VAriaNce reducTion Generator (ADVANTG) software implements methods developed specifically to provide highly effective variance reduction for complex radiation transport simulations such as those encountered with ITER. Using ADVANTG with the Monte Carlo N-particle (MCNP) radiation transport code, radiation responses were calculated on a fine spatial mesh with a high degree of statistical accuracy. In conclusion, advanced visualization tools were also developed and used to determine pipe cell connectivity, to facilitate model checking, and to post-process the transport simulation results.« less

  17. Using GIS and Ahp for Planning Primer Transportation of Forest Products

    NASA Astrophysics Data System (ADS)

    Akay, A. E.; Yılmaz, B.

    2017-11-01

    Primer transportation is one of the most costly and time consuming forestry activities in extraction of timber from forest lands. Transportation methods are essentially determined based on terrain characteristics, especially ground slope. Besides, unsuitable machine selection and unplanned operations may cause ecological damages such as soil disturbance. Soil damage can lead to long term impacts on forest ecosystem. Thus, the optimum transportation methods should be determined by considering not only economic factors but also topographical factors and soil conditions. In recent decades, some of the advanced features of Geographical Information System (GIS) assist decision makers to solve such complex transportation problems with various constraints. In this study, it was aimed to plan forest transportation operation by using GIS integrated Analytical Hierarchy Process (AHP) method, considering ground slope, soil type, and available transportation equipment in the region. This method was implemented within the border of İnegöl Forest Enterprise Chief in the city of Bursa in Turkey. Alternative transportation method included cable system, chute system, skidder, and farm tractor. GIS-based method integrated with AHP found that skidder was the optimal transportation method for about 60% of the study area, while farm tractor was the second most suitable method with 25% ground cover. The results indicated that GIS-based decision support systems can be effectively used as rational, quick, and economic tool for forest transportation planning.

  18. Primary system fission product release and transport: A state-of-the-art report to the committee on the safety of nuclear installations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wright, A.L.

    This report presents a summary of the status of research activities associated with fission product behavior (release and transport) under severe accident conditions within the primary systems of water-moderated and water-cooled nuclear reactors. For each of the areas of fission product release and fission product transport, the report summarizes relevant information on important phenomena, major experiments performed, relevant computer models and codes, comparisons of computer code calculations with experimental results, and general conclusions on the overall state of the art. Finally, the report provides an assessment of the overall importance and knowledge of primary system release and transport phenomena andmore » presents major conclusions on the state of the art.« less

  19. TRANSPORT PLANNING MODEL FOR WIDE AREA RECYCLING SYSTEM OF INDUSTRIAL WASTE PLASTIC

    NASA Astrophysics Data System (ADS)

    Arai, Yasuhiro; Kawamura, Hisashi; Koizumi, Akira; Mogi, Satoshi

    To date, the majority of industrial waste plastic generated in an urban city has been processed into landfill. However, it is now necessary to actively utilize that plastic as a useful resource to create a recycling society with a low environment influence. In order to construct a reasonable recycling system, it is necessary to address the "transportation problem," which means determining how much industrial waste plastic is to be transported to what location. With the goal of eliminating landfill processing, this study considers a transport planning model for industrial waste plastic applying linear programming. The results of running optimized calculations under given scenarios clarified not only the possibilities for recycle processing in the Metropolitan area, but also the validity of wide area recycling system.

  20. Early decline in glucose transport and metabolism precedes shift to ketogenic system in female aging and Alzheimer's mouse brain: implication for bioenergetic intervention.

    PubMed

    Ding, Fan; Yao, Jia; Rettberg, Jamaica R; Chen, Shuhua; Brinton, Roberta Diaz

    2013-01-01

    We previously demonstrated that mitochondrial bioenergetic deficits in the female brain accompanied reproductive senescence and was accompanied by a shift from an aerobic glycolytic to a ketogenic phenotype. Herein, we investigated the relationship between systems of fuel supply, transport and mitochondrial metabolic enzyme expression/activity during aging (3-15 months) in the hippocampus of nontransgenic (nonTg) background and 3xTgAD female mice. Results indicate that during female brain aging, both nonTg and 3xTgAD brains undergo significant decline in glucose transport, as detected by FDG-microPET, between 6-9 months of age just prior to the transition into reproductive senescence. The deficit in brain metabolism was sustained thereafter. Decline in glucose transport coincided with significant decline in neuronal glucose transporter expression and hexokinase activity with a concomitant rise in phosphorylated/inactivated pyruvate dehydrogenase. Lactate utilization declined in parallel to the decline in glucose transport suggesting lactate did not serve as an alternative fuel. An adaptive response in the nonTg hippocampus was a shift to transport and utilization of ketone bodies as an alternative fuel. In the 3xTgAD brain, utilization of ketone bodies as an alternative fuel was evident at the earliest age investigated and declined thereafter. The 3xTgAD adaptive response was to substantially increase monocarboxylate transporters in neurons while decreasing their expression at the BBB and in astrocytes. Collectively, these data indicate that the earliest change in the metabolic system of the aging female brain is the decline in neuronal glucose transport and metabolism followed by decline in mitochondrial function. The adaptive shift to the ketogenic system as an alternative fuel coincided with decline in mitochondrial function. Translationally, these data provide insights into the earliest events in bioenergetic aging of the female brain and provide potential targets for preventing shifts to less efficient bioenergetic fuels and transition to the ketogenic phenotype of the Alzheimer's brain.

  1. A new approach to tracer transport analysis: From fracture systems to strongly heterogeneous porous media

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tsang, Chin-Fu

    Many current development and utilization of groundwater resources include a study of their flow and transport properties. These properties are needed in evaluating possible changes in groundwater quality and potential transport of hazardous solutes through the groundwater system. Investigation of transport properties of fractured rocks is an active area of research. Most of the current approaches to the study of flow and transport in fractured rocks cannot be easily used for analysis of tracer transport field data. A new approach is proposed based on a detailed study of transport through a fracture of variable aperture. This is a two-dimensional stronglymore » heterogeneous permeable system. It is suggested that tracer breakthrough curves can be analyzed based on an aperture or permeability probability distribution function that characterizes the tracer flow through the fracture. The results are extended to a multi-fracture system and can be equally applied to a strongly heterogeneous porous medium. Finally, the need for multi-point or line and areal tracer injection and observation tests is indicated as a way to avoid the sensitive dependence of point measurements on local permeability variability. 30 refs., 15 figs.« less

  2. Impact of Wireless Power Transfer in Transportation: Future Transportation Enabler, or Near Term Distraction

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Onar, Omer C; Jones, Perry T

    2014-01-01

    While the total liquid fuels consumed in the U.S. for transportation of goods and people is expected to hold steady, or decline slightly over the next few decades, the world wide consumption is projected to increase of over 30% according to the Annual Energy Outlook 2014 [1]. The balance of energy consumption for transportation between petroleum fuels and electric energy, and the related greenhouse gas (GHG) emissions produced consuming either, is of particular interest to government administrations, vehicle OEMs, and energy suppliers. The market adoption of plug-in electric vehicles (PEVs) appears to be inhibited by many factors relating to themore » energy storage system (ESS) and charging infrastructure. Wireless power transfer (WPT) technologies have been identified as a key enabling technology to increase the acceptance of EVs. Oak Ridge National Laboratory (ORNL) has been involved in many research areas related to understanding the impacts, opportunities, challenges and costs related to various deployments of WPT technology for transportation use. Though the initial outlook for WPT deployment looks promising, many other emerging technologies have met unfavorable market launches due to unforeseen technology limitations, sometimes due to the complex system in which the new technology was placed. This paper will summarize research and development (R&D) performed at ORNL in the area of Wireless Power Transfer (WPT). ORNL s advanced transportation technology R&D activities provide a unique set of experienced researchers to assist in the creation of a transportation system level view. These activities range from fundamental technology development at the component level to subsystem controls and interactions to applicable system level analysis of impending market and industry responses and beyond.« less

  3. Multi-level examination of correlates of active transportation to school among youth living within 1 mile of their school.

    PubMed

    Gropp, Kathleen M; Pickett, William; Janssen, Ian

    2012-10-16

    Active transportation to school is a method by which youth can build physical activity into their daily routines. We examined correlates of active transportation to school at both individual- (characteristics of the individual and family) and area- (school and neighborhood) levels amongst youth living within 1 mile (1.6 km) of their school. Using the 2009/10 Canadian Health Behaviour in School-Aged Children (HBSC) survey, we selected records of students (n = 3 997) from 161 schools that resided in an urban setting and lived within 1 mile from their school. Student records were compiled from: (1) individual-level HBSC student questionnaires; (2) area-level administrator (school) questionnaires; and (3) area-level geographic information system data sources. The outcome, active transportation to school, was determined via a questionnaire item describing the method of transportation that individual students normally use to get to school. Analyses focused on factors at multiple levels that potentially contribute to student decisions to engage in active transportation. Multi-level logistic regression analyses were employed. Approximately 18% of the variance in active transportation was accounted for at the area-level. Several individual and family characteristics were associated with engagement in active transportation to school including female gender (RR vs. males = 0.86, 95% CI: 0.80-0.91), having ≥2 cars in the household (RR vs. no cars = 0.87, 0.74-0.97), and family socioeconomic status (RR for 'not well off' vs. 'very well off' = 1.14, 1.01-1.26). Neighborhood characteristics most strongly related to active transportation were: the length of roads in the 1 km buffer (RR in quartile 4 vs. quartile 1 = 1.23, 1.00-1.42), the amount of litter in the neighborhood (RR for 'major problem' vs. 'no problem' = 1.47, 1.16-1.57), and relatively hot climates (RR in quartile 4 vs. quartile 1 = 1.33 CI, 1.05-1.53). Engagement in active transportation to school was related to multiple factors at multiple levels. We identified gender, perception of residential neighborhood safety, the percentage of streets with sidewalks, and the total length of roads as the most important correlates of active transportation to school.

  4. Multi-level examination of correlates of active transportation to school among youth living within 1 mile of their school

    PubMed Central

    2012-01-01

    Background Active transportation to school is a method by which youth can build physical activity into their daily routines. We examined correlates of active transportation to school at both individual- (characteristics of the individual and family) and area- (school and neighborhood) levels amongst youth living within 1 mile (1.6 km) of their school. Methods Using the 2009/10 Canadian Health Behaviour in School-Aged Children (HBSC) survey, we selected records of students (n = 3 997) from 161 schools that resided in an urban setting and lived within 1 mile from their school. Student records were compiled from: (1) individual-level HBSC student questionnaires; (2) area-level administrator (school) questionnaires; and (3) area-level geographic information system data sources. The outcome, active transportation to school, was determined via a questionnaire item describing the method of transportation that individual students normally use to get to school. Analyses focused on factors at multiple levels that potentially contribute to student decisions to engage in active transportation. Multi-level logistic regression analyses were employed. Results Approximately 18% of the variance in active transportation was accounted for at the area-level. Several individual and family characteristics were associated with engagement in active transportation to school including female gender (RR vs. males = 0.86, 95% CI: 0.80-0.91), having ≥2 cars in the household (RR vs. no cars = 0.87, 0.74-0.97), and family socioeconomic status (RR for ‘not well off’ vs. ‘very well off’ = 1.14, 1.01-1.26). Neighborhood characteristics most strongly related to active transportation were: the length of roads in the 1 km buffer (RR in quartile 4 vs. quartile 1 = 1.23, 1.00-1.42), the amount of litter in the neighborhood (RR for ‘major problem’ vs. ‘no problem’ = 1.47, 1.16-1.57), and relatively hot climates (RR in quartile 4 vs. quartile 1 = 1.33 CI, 1.05-1.53). Conclusion Engagement in active transportation to school was related to multiple factors at multiple levels. We identified gender, perception of residential neighborhood safety, the percentage of streets with sidewalks, and the total length of roads as the most important correlates of active transportation to school. PMID:23067247

  5. Altered erythrocyte sodium-lithium counter-transport and Na+/K(+)-ATPase activity in cystic fibrosis.

    PubMed

    Luczay, A; Vásárhelyi, B; Dobos, M; Holics, K; Ujhelyi, R; Tulassay, T

    1997-03-01

    Patients with cystic fibrosis (CF) exhibit normal concentrations of sodium and chloride in spite of the disturbance of Cl- and Na+ transport in epithelial cells. To characterize compensatory mechanisms in the regulation of sodium homeostasis, erythrocytes of 13 CF patients were analysed for sodium-lithium counter-transport (SLC), Na+/K(+)-ATPase activity and intracellular sodium content. Values were compared to those of healthy controls. Patients with CF had normal serum sodium and chloride concentrations and renal excretions of these ions were within the physiological range. Intracellular sodium concentration was similar in the CF and the control group (6.8 +/- 2.2 vs 5.7 +/- 1.0 mmol/l RBCs). Red blood cells' SLC and Na+/ K(+)-ATPase activity were elevated in CF patients (381 +/- 106 mumol/h/l RBCs vs 281 +/- 64; p < 0.01) and (445 +/- 129 mumol ATP mg prot/h vs 322 +/- 84, p < 0.01). Our study demonstrates that transmembrane cation transport systems are highly activated in CF. The increased sodium transport may be part of a compensatory mechanism of sodium homeostasis in children with CF.

  6. Placental glucose and amino acid transport in calorie-restricted wild-type and Glut3 null heterozygous mice.

    PubMed

    Ganguly, Amit; Collis, Laura; Devaskar, Sherin U

    2012-08-01

    Calorie restriction (CR) decreased placenta and fetal weights in wild-type (wt) and glucose transporter (Glut) 3 heterozygous null (glut3(+/-)) mice. Because placental nutrient transport is a primary energy determinant of placentofetal growth, we examined key transport systems. Maternal CR reduced intra- and transplacental glucose and leucine transport but enhanced system A amino acid transport in wt mice. These transport perturbations were accompanied by reduced placental Glut3 and leucine amino acid transporter (LAT) family member 2, no change in Glut1 and LAT family member 1, but increased sodium coupled neutral amino acid transporter (SNAT) and SNAT2 expression. We also noted decreased total and active phosphorylated forms of mammalian target of rapamycin, which is the intracellular nutrient sensor, the downstream total P70S6 kinase, and pS6 ribosomal protein with no change in total and phosphorylated 4E-binding protein 1. To determine the role of placental Glut3 in mediating CR-induced placental transport changes, we next investigated the effect of gestational CR in glut3(+/-) mice. In glut3(+/-) mice, a key role of placental Glut3 in mediating transplacental and intraplacental glucose transport was established. In addition, reduced Glut3 results in a compensatory increase of leucine and system A transplacental transport. On the other hand, diminished Glut3-mediated intraplacental glucose transport reduced leucine transport and mammalian target of rapamycin and preserved LAT and enhancing SNAT. CR in glut3(+/-) mice further reduced transplacental glucose transport and enhanced system A amino acid transport, although the increased leucine transport was lost. In addition, increased Glut3 was seen and preserved Glut1, LAT, and SNAT. These placental changes collectively protect survival of wt and glut3(+/-) fetuses against maternal CR-imposed reduction of macromolecular nutrients.

  7. Quantifying the relative contributions of different solute carriers to aggregate substrate transport

    PubMed Central

    Taslimifar, Mehdi; Oparija, Lalita; Verrey, Francois; Kurtcuoglu, Vartan; Olgac, Ufuk; Makrides, Victoria

    2017-01-01

    Determining the contributions of different transporter species to overall cellular transport is fundamental for understanding the physiological regulation of solutes. We calculated the relative activities of Solute Carrier (SLC) transporters using the Michaelis-Menten equation and global fitting to estimate the normalized maximum transport rate for each transporter (Vmax). Data input were the normalized measured uptake of the essential neutral amino acid (AA) L-leucine (Leu) from concentration-dependence assays performed using Xenopus laevis oocytes. Our methodology was verified by calculating Leu and L-phenylalanine (Phe) data in the presence of competitive substrates and/or inhibitors. Among 9 potentially expressed endogenous X. laevis oocyte Leu transporter species, activities of only the uniporters SLC43A2/LAT4 (and/or SLC43A1/LAT3) and the sodium symporter SLC6A19/B0AT1 were required to account for total uptake. Furthermore, Leu and Phe uptake by heterologously expressed human SLC6A14/ATB0,+ and SLC43A2/LAT4 was accurately calculated. This versatile systems biology approach is useful for analyses where the kinetics of each active protein species can be represented by the Hill equation. Furthermore, its applicable even in the absence of protein expression data. It could potentially be applied, for example, to quantify drug transporter activities in target cells to improve specificity. PMID:28091567

  8. [Carbohydrate transport in the cestode Triaenophorus nodulosus].

    PubMed

    Izvekova, G I

    1989-01-01

    The data demonstrating the presence of the glucose active transport system in the cestode T. nodulosus are obtained. Kinetic characteristics of the transport are estimated and their dependence on the incubation temperature are shown. Heterogeneity of the worm body in respect to transport processes and their dependence on the physiological state of cestodes are discovered. The absorption of different forms of glucose is studied and the similarity of digestion processes in parasites and their hosts is shown.

  9. A Member of the Sugar Transporter Family, Stl1p Is the Glycerol/H+ Symporter in Saccharomyces cerevisiae

    PubMed Central

    Ferreira, Célia; van Voorst, Frank; Martins, António; Neves, Luisa; Oliveira, Rui; Kielland-Brandt, Morten C.; Lucas, Cândida; Brandt, Anders

    2005-01-01

    Glycerol and other polyols are used as osmoprotectants by many organisms. Several yeasts and other fungi can take up glycerol by proton symport. To identify genes involved in active glycerol uptake in Saccharomyces cerevisiae we screened a deletion mutant collection comprising 321 genes encoding proteins with 6 or more predicted transmembrane domains for impaired growth on glycerol medium. Deletion of STL1, which encodes a member of the sugar transporter family, eliminates active glycerol transport. Stl1p is present in the plasma membrane in S. cerevisiae during conditions where glycerol symport is functional. Both the Stl1 protein and the active glycerol transport are subject to glucose-induced inactivation, following identical patterns. Furthermore, the Stl1 protein and the glycerol symporter activity are strongly but transiently induced when cells are subjected to osmotic shock. STL1 was heterologously expressed in Schizosaccharomyces pombe, a yeast that does not contain its own active glycerol transport system. In S. pombe, STL1 conferred the ability to take up glycerol against a concentration gradient in a proton motive force-dependent manner. We conclude that the glycerol proton symporter in S. cerevisiae is encoded by STL1. PMID:15703210

  10. Low levels of graphene and graphene oxide inhibit cellular xenobiotic defense system mediated by efflux transporters.

    PubMed

    Liu, Su; Jiang, Wei; Wu, Bing; Yu, Jing; Yu, Haiyan; Zhang, Xu-Xiang; Torres-Duarte, Cristina; Cherr, Gary N

    2016-01-01

    Low levels of graphene and graphene oxide (GO) are considered to be environmentally safe. In this study, we analyzed the potential effects of graphene and GO at relatively low concentrations on cellular xenobiotic defense system mediated by efflux transporters. The results showed that graphene (<0.5 μg/mL) and GO (<20 μg/mL) did not decrease cell viability, generate reactive oxygen species, or disrupt mitochondrial function. However, graphene and GO at the nontoxic concentrations could increase calcein-AM (CAM, an indicator of membrane ATP-binding cassette (ABC) transporter) activity) accumulation, indicating inhibition of ABC transporters' efflux capabilities. This inhibition was observed even at 0.005 μg/mL graphene and 0.05 μg/mL GO, which are 100 times and 400 times lower than their lowest toxic concentration from cytotoxicity experiments, respectively. The inhibition of ABC transporters significantly increased the toxicity of paraquat and arsenic, known substrates of ABC transporters. The inhibition of ABC transporters was found to be based on graphene and GO damaging the plasma membrane structure and fluidity, thus altering functions of transmembrane ABC transporters. This study demonstrates that low levels of graphene and GO are not environmentally safe since they can significantly make cell more susceptible to other xenobiotics, and this chemosensitizing activity should be considered in the risk assessment of graphene and GO.

  11. Modular System to Enable Extravehicular Activity

    NASA Technical Reports Server (NTRS)

    Sargusingh, Miriam J.

    2012-01-01

    The ability to perform extravehicular activity (EVA), both human and robotic, has been identified as a key component to space missions to support such operations as assembly and maintenance of space systems (e.g. construction and maintenance of the International Space Station), and unscheduled activities to repair an element of the transportation and habitation systems that can only be accessed externally and via unpressurized areas. In order to make human transportation beyond lower Earth orbit (LEO) practical, efficiencies must be incorporated into the integrated transportation systems to reduce system mass and operational complexity. Affordability is also a key aspect to be considered in space system development; this could be achieved through commonality, modularity and component reuse. Another key aspect identified for the EVA system was the ability to produce flight worthy hardware quickly to support early missions and near Earth technology demonstrations. This paper details a conceptual architecture for a modular EVA system that would meet these stated needs for EVA capability that is affordable, and that could be produced relatively quickly. Operational concepts were developed to elaborate on the defined needs, and to define the key capabilities, operational and design constraints, and general timelines. The operational concept lead to a high level design concept for a module that interfaces with various space transportation elements and contains the hardware and systems required to support human and telerobotic EVA; the module would not be self-propelled and would rely on an interfacing element for consumable resources. The conceptual architecture was then compared to EVA Systems used in the Space Shuttle Orbiter, on the International Space Station to develop high level design concepts that incorporate opportunities for cost savings through hardware reuse, and quick production through the use of existing technologies and hardware designs. An upgrade option was included to make use of the developing suit port technologies.

  12. Evaluation of the impact of the I-66 active traffic management system : final report.

    DOT National Transportation Integrated Search

    2016-09-01

    Construction of a Virginia Department of Transportation project to install an Active Traffic Management (ATM) system on Interstate-66 (I-66) from U.S. 29 in Centreville to the Capital Beltway (I-495) was completed in September 2015. The project was c...

  13. Induction of the high-affinity Na(+)-dependent glutamate transport system XAG- by hypertonic stress in the renal epithelial cell line NBL-1.

    PubMed Central

    Ferrer-Martinez, A; Felipe, A; Nicholson, B; Casado, J; Pastor-Anglada, M; McGivan, J

    1995-01-01

    The high-affinity Na(+)-dependent glutamate transport system XAG- is induced (threefold increase in Vmax. with no change in Km) by hypertonicity in the renal epithelial cell line NBL-1. This effect is dependent on protein synthesis and glycosylation and is accompanied by an increase in EAAC1 mRNA levels. Other Na(+)-dependent transport systems in this cell line do not respond to hypertonic stress. In contrast to recent findings [Ruiz-Montasell, Gomez-Angelats, Casado, Felipe, McGivan and Pastor-Anglada (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 9569-9573] showing that increased system A activity after hyperosmotic shock results from induction of a regulatory protein, this is the first demonstration that hypertonicity may increase the expression of the gene for an amino acid transport protein itself. Images Figure 4 PMID:7654212

  14. System dynamics of subcellular transport.

    PubMed

    Chen, Vivien Y; Khersonsky, Sonya M; Shedden, Kerby; Chang, Young Tae; Rosania, Gus R

    2004-01-01

    In pharmacokinetic experiments, interpretations often hinge on treating cells as a "black box": a single, lumped compartment or boundary. Here, a combinatorial library of fluorescent small molecules was used to visualize subcellular transport pathways in living cells, using a kinetic, high content imaging system to monitor spatiotemporal variations of intracellular probe distribution. Most probes accumulate in cytoplasmic vesicles and probe kinetics conform to a nested, two-compartment dynamical system. At steady state, probes preferentially partition from the extracellular medium to the cytosol, and from the cytosol to cytoplasmic vesicles, with hydrophobic molecules favoring sequestration. Altogether, these results point to a general organizing principle underlying the system dynamics of subcellular, small molecule transport. In addition to plasma membrane permeability, subcellular transport phenomena can determine the active concentration of small molecules in the cytosol and the efflux of small molecules from cells. Fundamentally, direct observation of intracellular probe distribution challenges the simple boundary model of classical pharmacokinetics, which considers cells as static permeability barriers.

  15. Influence of nucleation seeding on the compressive strength of ordinary Portland cement and alkali activated blast-furnace slag

    DOT National Transportation Integrated Search

    2011-05-10

    The Intelligent Transportation Systems (ITS) Joint Program Office (JPO) of the U.S. Department of Transportation (USDOT) has been collecting the benefits, costs, lessons learned, and deployment status information of ITS. Such information, intended to...

  16. Mass Transport: Circulatory System with Emphasis on Nonendothermic Species.

    PubMed

    Crossley, Dane A; Burggren, Warren W; Reiber, Carl L; Altimiras, Jordi; Rodnick, Kenneth J

    2016-12-06

    Mass transport can be generally defined as movement of material matter. The circulatory system then is a biological example given its role in the movement in transporting gases, nutrients, wastes, and chemical signals. Comparative physiology has a long history of providing new insights and advancing our understanding of circulatory mass transport across a wide array of circulatory systems. Here we focus on circulatory function of nonmodel species. Invertebrates possess diverse convection systems; that at the most complex generate pressures and perform at a level comparable to vertebrates. Many invertebrates actively modulate cardiovascular function using neuronal, neurohormonal, and skeletal muscle activity. In vertebrates, our understanding of cardiac morphology, cardiomyocyte function, and contractile protein regulation by Ca2+ highlights a high degree of conservation, but differences between species exist and are coupled to variable environments and body temperatures. Key regulators of vertebrate cardiac function and systemic blood pressure include the autonomic nervous system, hormones, and ventricular filling. Further chemical factors regulating cardiovascular function include adenosine, natriuretic peptides, arginine vasotocin, endothelin 1, bradykinin, histamine, nitric oxide, and hydrogen sulfide, to name but a few. Diverse vascular morphologies and the regulation of blood flow in the coronary and cerebral circulations are also apparent in nonmammalian species. Dynamic adjustments of cardiovascular function are associated with exercise on land, flying at high altitude, prolonged dives by marine mammals, and unique morphology, such as the giraffe. Future studies should address limits of gas exchange and convective transport, the evolution of high arterial pressure across diverse taxa, and the importance of the cardiovascular system adaptations to extreme environments. © 2017 American Physiological Society. Compr Physiol 7:17-66, 2017. Copyright © 2017 John Wiley & Sons, Inc.

  17. Computational Structures Technology for Airframes and Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K. (Compiler); Housner, Jerrold M. (Compiler); Starnes, James H., Jr. (Compiler); Hopkins, Dale A. (Compiler); Chamis, Christos C. (Compiler)

    1992-01-01

    This conference publication contains the presentations and discussions from the joint University of Virginia (UVA)/NASA Workshops. The presentations included NASA Headquarters perspectives on High Speed Civil Transport (HSCT), goals and objectives of the UVA Center for Computational Structures Technology (CST), NASA and Air Force CST activities, CST activities for airframes and propulsion systems in industry, and CST activities at Sandia National Laboratory.

  18. S-nitrosothiol transport via PEPT2 mediates biological effects of nitric oxide gas exposure in macrophages.

    PubMed

    Brahmajothi, Mulugu V; Sun, Natalie Z; Auten, Richard L

    2013-02-01

    The pharmacological effects of nitric oxide (NO) administered as a gas are dependent on the conversion to S-nitrosocysteine, and as such are largely mediated by the L-type amino-acid transporters (LATs) in several cell types. The dipeptide transporter PEPT2 has been proposed as a second route for S-nitrosothiol (SNO) transport, but this has never been demonstrated. Because NO governs important immune functions in alveolar macrophages, we exposed rat alveolar macrophages (primary and NR8383 cells) to NO gas at the air-liquid interface ± LPS stimulation in the presence of PEPT2 substrate Cys-Gly (or the LAT substrate L-Cys) ± transporter competitors. We found that SNO uptake and NO-dependent actions, such as the activation of soluble guanylyl cyclase (sGC), the augmentation of sGC-dependent filamentous actin (F-actin) polymerization, phagocytosis, and the inhibition of NF-κB activation, were significantly augmented by the addition of Cys-Gly in a manner dependent on PEPT2 transport. We found parallel (and greater) effects that were dependent on LAT transport. The contribution of cystine/cysteine shuttling via system x cystine transporter (xCT) to SNO uptake was relatively minor. The observed effects were unaffected by NO synthase inhibition. The NO gas treatment of alveolar macrophages increased SNO uptake, the activation of sGC, F-actin polymerization, and phagocytosis, and inhibited NF-κB activation, in a manner dependent on SNO transport via PEPT2, as well as via LAT.

  19. Relationships among community characteristics and walking and bicycling for transportation or recreation.

    PubMed

    Zlot, Amy I; Schmid, Tom L

    2005-01-01

    Compare walking and bicycling for transportation and recreation with the percentage of the community devoted to parklands. Behavioral Risk Factor Surveillance System (N = 206,992), Nationwide Personal Transportation Survey (N = 409,025), and Trust for Public Land (N = 55) data were used to estimate recreational walking and bicycling, utilitarian walking and bicycling, and parkland as a percentage of city acreage. Data were linked at the metropolitan statistical area or city level (N = 34). Pearson correlation coefficients were used to assess the associations among recreational and utilitarian walking and bicycling and parkland acreage. Utilitarian walking and bicycling and parkland acreage were significantly correlated (r = .62, p < .0001). No significant relationships were observed for leisure time walking or bicycling. Communities with more parks had significantly higher levels of walking and bicycling for transportation. Urban design features associated with leisure time physical activity might differ from those associated with transportation-related physical activity. Further studies are needed to articulate the relationships among community attributes and purposes of physical activity.

  20. Interferon-gamma regulates nucleoside transport systems in macrophages through signal transduction and activator of transduction factor 1 (STAT1)-dependent and -independent signalling pathways.

    PubMed Central

    Soler, Concepció; Felipe, Antonio; García-Manteiga, José; Serra, Maria; Guillén-Gómez, Elena; Casado, F Javier; MacLeod, Carol; Modolell, Manuel; Pastor-Anglada, Marçal; Celada, Antonio

    2003-01-01

    The expressions of CNT and ENT (concentrative and equilibrative nucleoside transporters) in macrophages are differentially regulated by IFN-gamma (interferon-gamma). This cytokine controls gene expression through STAT1-dependent and/or -independent pathways (where STAT1 stands for signal transduction and activator of transcription 1). In the present study, the role of STAT1 in the response of nucleoside transporters to IFN-gamma was studied using macrophages from STAT1 knockout mice. IFN-gamma triggered an inhibition of ENT1-related nucleoside transport activity through STAT1-dependent mechanisms. Such inhibition of macrophage growth and ENT1 activity by IFN-gamma is required for DNA synthesis. Interestingly, IFN-gamma led to an induction of the CNT1- and CNT2-related nucleoside transport activities independent of STAT1, thus ensuring the supply of extracellular nucleosides for the STAT1-independent RNA synthesis. IFN-gamma up-regulated CNT2 mRNA and CNT1 protein levels and down-regulated ENT1 mRNA in both wild-type and STAT1 knockout macrophages. This is consistent with a STAT1-independent, long-term-mediated, probably transcription-dependent, regulation of nucleoside transporter genes. Moreover, STAT1-dependent post-transcriptional mechanisms are implicated in the regulation of ENT1 activity. Although nitric oxide is involved in the regulation of ENT1 activity in B-cells at a post-transcriptional level, our results show that STAT1-dependent induction of nitric oxide by IFN-gamma is not implicated in the regulation of ENT1 activity in macrophages. Our results indicate that both STAT1-dependent and -independent pathways are involved in the regulation of nucleoside transporters by IFN-gamma in macrophages. PMID:12868960

  1. A biographical memoir of Donald Edward White

    USGS Publications Warehouse

    Muffler, L. J. Patrick

    2016-01-01

    Donald E. White was a leading scientist for the U.S. Geological Survey, where his career was devoted almost entirely to the study of hydrothermal processes in the Earth’s crust, from the dual perspectives of active geothermal systems and of extinct hydrothermal systems now represented only by ore deposits and alteration patterns. White was devoted to analyzing the mechanisms by which ore-forming metals are concentrated, transported, and deposited. His early work on antimony deposits and on mercury transport led to the understanding that these elements, as well as some precious metals, were concentrated in hydrothermal convection systems characterized by dilute chloride waters of predominantly meteoric origin. He concluded, on the other hand, that base metals required more concentrated brines, as was impressively confirmed in the early 1960s by the discovery of the metal-rich fluids of the Salton Sea geothermal system and subsequently by the recognition of sulfide-depositing hydrothermal systems on the sea floor. His studies of active hot-spring systems elucidated the principles of geyser activity and provided the scientific foundation for research programs aimed at the understanding of geothermal systems throughout the world.

  2. A role for gamma-glutamyl transpeptidase and the amino acid transport system xc- in cystine transport by a human pancreatic duct cell line.

    PubMed Central

    Sweiry, J H; Sastre, J; Viña, J; Elsässer, H P; Mann, G E

    1995-01-01

    1. The roles of the gamma-glutamyl cycle and the anionic amino acid transport system xc- in mediating L-cystine uptake were investigated in cultured human pancreatic duct PaTu 8902 cells. This cell line exhibits morphological features of normal pancreatic duct cells and expresses gamma-glutamyl transpeptidase (gamma-GT, EC 2.3.2.2), an enzyme involved in the metabolism and regulation of intracellular glutathione (GSH). 2. Uptake of L-cystine (10 microM) was linear for up to 10 min, temperature dependent, Na+ independent, saturable (Michaelis-Menten constant (Km), 86 +/- 25 microM; maximal velocity (Vmax), 109 +/- 33 nmol (mg protein)-1 h-1) and reduced by 80-90% by a 50-fold excess concentration of L-glutamate and L-homocysteic acid, but not L-aspartate. These transport properties resemble those described for system xc-, which exchanges cystine for intracellular glutamate. 3. Acivicin, a known inhibitor of gamma-GT, decreased gamma-GT activity from 2.58 +/- 0.96 to 0.97 +/- 0.11 mU (mg protein)-1 and decreased the initial rates of L-cystine and L-glutamine uptake by 41-55%. Anthglutin (1-gamma-L-glutamyl-2-(2-carboxyphenylhyl)hydrazine), a structurally different inhibitor of gamma-GT, also caused a concentration-dependent (0.01-1 mM) decrease in gamma-GT activity and L-cystine uptake. 4. Neither acivicin nor anthglutin inhibited the uptake of L-glutamate, a poor substrate for gamma-GT. 5. In the presence of a 500-fold excess concentration of glutamate, which should abolish entry of cystine via system xc-, the remaining fraction of cystine transport was inhibited by 50% by acivicin, suggesting that transport is, in part, dependent on the activity of gamma-GT. 6. Cystine transport was also 60-80% inhibited by a series of gamma-glutamyl amino acids (5 mM) including gamma-glutamyl-glutamate, gamma-glutamyl-glutamine and gamma-glutamyl-glycine. alpha-Dipeptides inhibited cystine transport by only 6-22%. 7. These findings demonstrate that in human pancreatic duct PaTu 8902 cells, cystine uptake is mediated by system xc- (50-60%) and the gamma-glutamyl cycle. Our results provide the first evidence linking gamma-GT with cystine transport in human epithelial cells and are of relevance in view of the importance of cystine as a sulphur amino acid source for GSH synthesis in cells exposed to oxidative stress. Images Figure 1 PMID:7658371

  3. The relationship between the electrochemical proton gradient and active transport in Escherichia coli membrane vesicles.

    PubMed

    Ramos, S; Kaback, H R

    1977-03-08

    In the previous paper [ramos, S., and Kaback, H.R. (1977), Biochemistry 16 (preceding paper in this issue)], it was demonstrated that Escherichia coli membrane vesicles generate a large electrochemical proton gradient (delta-muH+) under appropriate conditions, and some of the properties of delta-muH+ and its component forces [i.e., the membrane potential (delta psi) and the chemical gradient of protons (deltapH)] were described. In this paper, the relationship between delta-muH+, delta psi, and deltapH and the active transport of specific solutes is examined. Addition of lactose or glucose 6-phosphate to membrane vesicles containing the appropriate transport systems results in partial collapse of deltapH, providing direct evidence for the suggestion that respiratory energy can drive active transport via the pH gradient across the membrane. Titration studies with valinomycin and nigericin lead to the conclusion that, at pH 5.5, there are two general classes of transport systems: those that are driven primarily by delta-muH+ (lactose, proline, serine, glycine, tyrosine, glutamate, leucine, lysine, cysteine, and succinate) and those that are driven primarily by deltapH (glucose 6-phosphate, D-lactate, glucuronate, and gluconate). Importantly, however, it is also demonstrated that at pH 7.5, all of these transport systems are driven by delta psi which comprises the only component of delta-muH+ at this external pH. In addition, the effect of external pH on the steady-state levels of accumulation of different solutes is examined, and it is shown that none of the pH profiles correspond to those observed for delta-muH+, delta psi, or deltapH. Moreover, at external pH values above 6.0-6.5, delta-muH+ is insufficient to account for the concentration gradients established for each substrate unless the stoichiometry between protons and accumulated solutes is greater than unity. The results confirm many facets of the chemiosmotic hypothesis, but they also extend the concept in certain important respects and allow explanations for some earlier observations which seemed to preclude the involvement of chemiosmotic phenomena in active transport.

  4. Survey of RFID and Its Application to International Ocean/Air Container Tracking

    NASA Astrophysics Data System (ADS)

    Katayama, Minoru; Nakada, Hiroshi; Hayashi, Hitoshi; Shimizu, Masashi

    “Internet of Things” (IoT) requires information to be collected from “anything”, “anytime”, and “anywhere”. In order to achieve this, wireless devices are required that have (1) automatic data acquisition capability, (2) small size, (3) long life, and (4) long range communication capability. One way to meet these requirements is to adopt active Radio Frequency Identification (RFID) systems. Active RFID is more advantageous than passive RFID and enables higher data reading performance over longer distances. This paper surveys active RFID systems, the services they currently promise to provide, technical problems common to these services, and the direction in which research should head in the future. It also reports the results of EPCglobal (EPC: Electronic Product Code) pilot tests conducted on global logistics for tracking ocean/air container transportation using active RFID systems for which we developed several new types of active RFID tags. The test results confirm that our active RFID tags have sufficient capability and low power consumption to well support ocean/air transportation and logistics service.

  5. 78 FR 57455 - Pipeline Safety: Information Collection Activities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-18

    ... ``. . . system-specific information, including pipe diameter, operating pressure, product transported, and...) must provide contact information and geospatial data on their pipeline system. This information should... Mapping System (NPMS) to support various regulatory programs, pipeline inspections, and authorized...

  6. Technology needs for lunar and Mars space transfer systems

    NASA Technical Reports Server (NTRS)

    Woodcock, Gordon R.; Cothran, Bradley C.; Donahue, Benjamin; Mcghee, Jerry

    1991-01-01

    The determination of appropriate space transportation technologies and operating modes is discussed with respect to both lunar and Mars missions. Three levels of activity are set forth to examine the sensitivity of transportation preferences including 'minimum,' 'full science,' and 'industrialization and settlement' categories. High-thrust-profile missions for lunar and Mars transportation are considered in terms of their relative advantages, and transportation options are defined in terms of propulsion and braking technologies. Costs and life-cycle cost estimates are prepared for the transportation preferences by using a parametric cost model, and a return-on-investment summary is given. Major technological needs for the programs are listed and include storable propulsion systems; cryogenic engines and fluids management; aerobraking; and nuclear thermal, nuclear electric, electric, and solar electric propulsion technologies.

  7. A vacuolar membrane protein Avt7p is involved in transport of amino acid and spore formation in Saccharomyces cerevisiae.

    PubMed

    Tone, Junichi; Yamanaka, Atsushi; Manabe, Kunio; Murao, Nami; Kawano-Kawada, Miyuki; Sekito, Takayuki; Kakinuma, Yoshimi

    2015-01-01

    Active transport systems for various amino acids operate in the vacuolar membrane of Saccharomyces cerevisiae. The gene families for vacuolar amino acid transporters were identified by reverse genetics experiments. In the AVT transporter family, Avt1p works for active uptake of amino acid into vacuole, and Avt3p, Avt4p, and Avt6p for active extrusion of amino acid from vacuole to cytosol. Here, we found green fluorescent protein-tagged Avt7p, an unidentified member of the AVT family, localized to the vacuolar membrane of S. cerevisiae. Disruption of the AVT7 gene enhanced both vacuolar contents of several amino acids and uptake activities of glutamine and proline by vacuolar membrane vesicles. Efficiency of spore formation was impaired by the disruption of the AVT7 gene, suggesting the physiological importance of Avt7p-dependent efflux of amino acid from vacuoles under nutrient-poor condition.

  8. Effect of the porous structure of activated carbon on the adsorption kinetics of gold(I) cyanide complex

    NASA Astrophysics Data System (ADS)

    Ibragimova, P. I.; Grebennikov, S. F.; Gur'yanov, V. V.; Fedyukevich, V. A.; Vorob'ev-Desyatovskii, N. V.

    2014-06-01

    The effect the porous structure of activated carbons obtained from furfural and coconut shells has on the kinetics of [Au(CN)2]- ion adsorption is studied. Effective diffusion coefficients for [Au(CN)2]- anions in transport and adsorbing pores and mass transfer coefficients in a transport system of the pores and in microporous zones are calculated using the statistical moments of the kinetic curve.

  9. An investigation of air transportation technology at the Massachusetts Institute of Technology, 1992-1993

    NASA Technical Reports Server (NTRS)

    Simpson, Robert W.

    1994-01-01

    An investigation of air transportation technology at MIT during 1992 - 1993 is presented. One completed project and two continuing research activities are under the sponsorship of the FAA/NASA Joint University Program. The completed project was on tracking aircraft around a turn with wind effects. Active research projects are on ASLOTS - an interactive adaptive system of automated approach spacing of aircraft and alerting in automated and datalink capable cockpits.

  10. Using Grey Relational Analysis to Evaluate Energy Consumption, CO2 Emissions and Growth Patterns in China’s Provincial Transportation Sectors

    PubMed Central

    Yuan, Changwei; Liu, Hongchao

    2017-01-01

    The transportation sector is a complex system. Collecting transportation activity and the associated emissions data is extremely expensive and time-consuming. Grey Relational Analysis provides a viable alternative to overcome data insufficiency and gives insights for decision makers into such a complex system. In this paper, we achieved three major goals: (i) we explored the inter-relationships among transportation development, energy consumption and CO2 emissions for 30 provincial units in China; (ii) we identified the transportation development mode for each individual province; and (iii) we revealed policy implications regarding the sustainable transportation development at the provincial level. We can classify the 30 provinces into eight development modes according to the calculated Grey Relational Grades. Results also indicated that energy consumption has the largest influence on CO2 emission changes. Lastly, sustainable transportation policies were discussed at the province level according to the level of economy, urbanization and transportation energy structure. PMID:29292779

  11. Decreased membrane potassium permeability and transport in human chronic leukemic and tonsillar lymphocytes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Segel, G.B.; Lichtman, M.A.

    Human blood T-lymphocytes increase their potassium (K/sup +/) permeability and active K/sup +/ transport following lectin or antigen stimulation. We have studied the permeability and active transport of K/sup +/ by lymphocytes in chronic lymphocytic leukemia (CLL) to determine if their membrane K/sup +/ transport was similar to resting or lectin-stimulated normal blood lymphocytes. K/sup +/ transport was assessed both by the rate of isotopic /sup 42/K/sup +/ uptake and by the rate of change in cell K/sup +/ concentration after inhibition of the K/sup +/ transport system with ouabain. CLL lymphocytes had a marked decrease in membrane K/sup +/more » permeability and active transport of K/sup +/ when compared to blood T lymphocytes. K/sup +/ transport in five subjects with CLL (10 mmol . 1 cell water/sup -1/ . h/sup -1/) was half that in normal blood T-lymphocytes (20 mmol . 1 cell water/sup -1/ h/sup -1/). Phytohemagglutinin (PHA) treatment of CLL lymphocytes did not increase significantly their active K/sup +/ transport, whereas K/sup +/ transport by normal T-lymphocytes increased by 100%. Since there were 73% T-lymphocytes in normal blood and 14% in CLL blood, the difference in membrane K/sup +/ turnover could be related either to neoplasia or to the proposed B-lymphocyte origin of CLL. We studied human tonsillar lymphocytes which contained a mean of 34% T-cells. In five studies of tonsils, K/sup +/ transport was 14 mmol . 1 cell water/sup -1/ . h/sup -1/ and treatment with PHA increased K/sup +/ transport only 30%. The intermediate values for basal K/sup +/ transport and K/sup +/ transport in response to PHA in tonsillar lymphocytes were consistent with the proportion of T-lymphocytes present. These data sugges t that B-lymphocytes have reduced membrane permeability and active transport of K/sup +/. Thus the marked decrease in CLL lymphocyte membrane K/sup +/ permeability and transport may be a reflection of its presumed B-cell origin, rather than a membrane alteration related to malignant transformation.« less

  12. 49 CFR 25.520 - Job classification and structure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 25.520 Transportation Office of the Secretary of Transportation NONDISCRIMINATION ON THE BASIS OF SEX... Basis of Sex in Employment in Education Programs or Activities Prohibited § 25.520 Job classification... based on sex; or (c) Maintain or establish separate lines of progression, seniority systems, career...

  13. Calibration and operational data for a compact photodiode detector useful for monitoring the location of moving sources of positron emitting radioisotopes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Marsland, M. G.; Dehnel, M. P.; Theroux, J.

    2013-04-19

    D-Pace has developed a compact cost-effective gamma detector system based on technology licensed from TRIUMF. These photodiode detectors are convenient for detecting the presence of positron emitting radioisotopes, particularly for the case of transport of radioisotopes from a PET cyclotron to hotlab, or from one location to another in an automated radiochemistry processing unit. This paper describes recent calibration experiments undertaken at the Turku PET Centre for stationary and moving sources of F18 and C11 in standard setups. The practical diagnostic utility of using several of these devices to track the transport of radioisotopes from the cyclotron to hotlab ismore » illustrated. For example, such a detector system provides: a semi-quantitative indication of total activity, speed of transport, location of any activity lost en route and effectiveness of follow-up system flushes, a means of identifying bolus break-up, feedback useful for deciding when to change out tubing.« less

  14. The Natural Protective Mechanism Against Hyperglycemia in Vascular Endothelial Cells

    PubMed Central

    Riahi, Yael; Sin-Malia, Yoav; Cohen, Guy; Alpert, Evgenia; Gruzman, Arie; Eckel, Juergen; Staels, Bart; Guichardant, Michel; Sasson, Shlomo

    2010-01-01

    OBJECTIVE Vascular endothelial cells (VECs) downregulate their rate of glucose uptake in response to hyperglycemia by decreasing the expression of their typical glucose transporter GLUT-1. Hitherto, we discovered critical roles for the protein calreticulin and the arachidonic acid–metabolizing enzyme 12-lipoxygenase in this autoregulatory process. The hypothesis that 4-hydroxydodeca-(2E,6Z)-dienal (4-HDDE), the peroxidation product of 12-lipoxygenase, mediates this downregulatory mechanism by activating peroxisome proliferator–activated receptor (PPAR) δ was investigated. RESEARCH DESIGN AND METHODS Effects of 4-HDDE and PPARδ on the glucose transport system and calreticulin expression in primary bovine aortic endothelial cells were evaluated by pharmacological and molecular interventions. RESULTS Using GW501516 (PPARδ agonist) and GSK0660 (PPARδ antagonist), we discovered that high-glucose–induced downregulation of the glucose transport system in VECs is mediated by PPARδ. A PPAR-sensitive luciferase reporter assay in VECs revealed that high glucose markedly increased luciferase activity, while GSK0660 abolished it. High-performance liquid chromatography analysis showed that high-glucose incubation substantially elevated the generation of 4-HDDE in VECs. Treatment of VECs, exposed to normal glucose, with 4-HDDE mimicked high glucose and downregulated the glucose transport system and increased calreticulin expression. Like high glucose, 4-HDDE significantly activated PPARδ in cells overexpressing human PPAR (hPPAR)δ but not hPPARα, -γ1, or -γ2. Moreover, silencing of PPARδ prevented high-glucose–dependent alterations in GLUT-1 and calreticulin expression. Finally, specific binding of PPARδ to a PPAR response element in the promoter region of the calreticulin gene was identified by utilizing a specific chromatin immunoprecipitation assay. CONCLUSIONS Collectively, our data show that 4-HDDE plays a central role in the downregulation of glucose uptake in VECs by activating PPARδ. PMID:20107107

  15. Na+-dependent and Na+-independent betaine transport across the apical membrane of rat renal epithelium.

    PubMed

    Cano, Mercedes; Calonge, María L; Ilundáin, Anunciación A

    2015-10-01

    The low renal excretion of betaine indicates that the kidney efficiently reabsorbs the betaine filtered by the glomeruli but the mechanisms involved in such a process have been scarcely investigated. We have detected concentrative and non-concentrative betaine transport activity in brush-border membrane vesicles (BBMV) from rat renal cortex and medulla. The concentrative system is the Sodium/Imino-acid Transporter 1 (SIT1) because it is Na+- and Cl--dependent, electrogenic and is inhibited by an anti-SIT1 antibody. Its apparent affinity constant for betaine, Kt, is 1.1±0.5 mM and its maximal transport velocity, Vmax, 0.5±0.1 nmol betaine/mg protein/s. Inhibitors of the Na+/Cl-/betaine uptake are L-proline (75%) and cold betaine, L-carnitine and choline (40-60%). Neither creatine, TEA, taurine, β-alanine, GABA nor glycine significantly inhibited Na+/Cl-/betaine uptake. The non-concentrative betaine transport system is Na+- and H+-independent, electroneutral, with a Kt for betaine of 47±7 μM and a Vmax of 7.8±1 pmol betaine/mg protein/s. Its transport activity is nearly abolished by betaine, followed by L-carnitine (70-80%) and proline (40-50%), but a difference from the Na+/Cl-/betaine transport is that it is inhibited by TEA (approx. 50%) and unaffected by choline. The underlying carrier functions as an antiporter linking betaine entry into the BBMV with the efflux of either L-carnitine or betaine, an exchange unaffected by the anti-SIT1 antibody. As far as we know this is the first work reporting that betaine crosses the apical membrane of rat renal epithelium by SIT1 and by a Na+- and H+-independent transport system. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Sirtuin activation: a role for plasma membrane in the cell growth puzzle.

    PubMed

    Crane, Frederick L; Navas, Plácido; Low, Hans; Sun, Iris L; de Cabo, Rafael

    2013-04-01

    For more than 20 years, the observation that impermeable oxidants can stimulate cell growth has not been satisfactorily explained. The discovery of sirtuins provides a logical answer to the puzzle. The NADH-dependent transplasma membrane electron transport system, which is stimulated by growth factors and interventions such as calorie restriction, can transfer electrons to external acceptors and protect against stress-induced apoptosis. We hypothesize that the activation of plasma membrane electron transport contributes to the cytosolic NAD(+) pool required for sirtuin to activate transcription factors necessary for cell growth and survival.

  17. [The participation of the transport-barrier functions of the plasma membrane in the development of fluoroquinolone (ciprofloxacin) resistance in Acholeplasma laidlawii].

    PubMed

    Abramycheva, N Iu; Govorun, V M

    2000-01-01

    The role of transport activity of Acholeplasma laidlawii plasmatic membrane in the development of resistance to ciprofloxacin was investigated. It was shown that ethidium bromide used as fluoroquinolone analogue in plasmatic membrane efflux pump was accumulated in ciprofloxacin-resistant cells in much less amount. It was estimated that ethidium bromide efflux depended on temperature, glucose and transmembrane electro-chemical proton potential. Inhibitors of efflux systems--reserpine and verapamil enhanced the ethidium bromide accumulation much more intensively in ciprofloxacin resistant cells. The results of investigation allowed to consider the existence of active efflux system for toxic agents in acholeplasma; in the case of ciprofloxacin-resistant strain these systems are inducible.

  18. The transport of Staufen2-containing ribonucleoprotein complexes involves kinesin motor protein and is modulated by mitogen-activated protein kinase pathway.

    PubMed

    Jeong, Ji-Hye; Nam, Yeon-Ju; Kim, Seok-Yong; Kim, Eung-Gook; Jeong, Jooyoung; Kim, Hyong Kyu

    2007-09-01

    There is increasing evidence showing that mRNA is transported to the neuronal dendrites in ribonucleoprotein (RNP) complexes or RNA granules, which are aggregates of mRNA, rRNA, ribosomal proteins, and RNA-binding proteins. In these RNP complexes, Staufen, a double-stranded RNA-binding protein, is believed to be a core component that plays a key role in the dendritic mRNA transport. This study investigated the molecular mechanisms of the dendritic mRNA transport using green fluorescent protein-tagged Staufen2 produced employing a Sindbis viral expression system. The kinesin heavy chain was found to be associated with Staufen2. The inhibition of kinesin resulted in a significant decrease in the level of dendritic transport of the Staufen2-containing RNP complexes in neurons under non-stimulating or stimulating conditions. This suggests that the dendritic transport of the Staufen2-containing RNP complexes use kinesin as a motor protein. A mitogen-activated protein kinase inhibitor, PD98059, inhibited the activity-induced increase in the amount of both the Staufen2-containing RNP complexes and Ca(2+)/calmodulin-dependent protein kinase II alpha-subunit mRNA in the distal dendrites of cultured hippocampal neurons. Overall, these results suggest that dendritic mRNA transport is mediated via the Staufen2 and kinesin motor proteins and might be modulated by the neuronal activity and mitogen-activated protein kinase pathway.

  19. Diverse Functional Properties of Wilson Disease ATP7B Variants

    PubMed Central

    Huster, Dominik; Kühne, Angelika; Bhattacharjee, Ashima; Raines, Lily; Jantsch, Vanessa; Noe, Johannes; Schirrmeister, Wiebke; Sommerer, Ines; Sabri, Osama; Berr, Frieder; Mössner, Joachim; Stieger, Bruno; Caca, Karel; Lutsenko, Svetlana

    2012-01-01

    BACKGROUND & AIMS Wilson disease is a severe disorder of copper metabolism caused by mutations in ATP7B, which encodes a copper-transporting adenosine triphosphatase. The disease presents with a variable phenotype that complicates the diagnostic process and treatment. Little is known about the mechanisms that contribute to the different phenotypes of the disease. METHODS We analyzed 28 variants of ATP7B from patients with Wilson disease that affected different functional domains; the gene products were expressed using the baculovirus expression system in Sf9 cells. Protein function was analyzed by measuring catalytic activity and copper (64Cu) transport into vesicles. We studied intracellular localization of variants of ATP7B that had measurable transport activities and were tagged with green fluorescent protein in mammalian cells using confocal laser scanning microscopy. RESULTS Properties of ATP7B variants with pathogenic amino-acid substitution varied greatly even if substitutions were in the same functional domain. Some variants had complete loss of catalytic and transport activity, whereas others lost transport activity but retained phosphor-intermediate formation or had partial losses of activity. In mammalian cells, transport-competent variants differed in stability and subcellular localization. CONCLUSIONS Variants in ATP7B associated with Wilson disease disrupt the protein’s transport activity, result in its mislocalization, and reduce its stability. Single assays are insufficient to accurately predict the effects of ATP7B variants the function of its product and development of Wilson disease. These findings will contribute to our understanding of genotype–phenotype correlation and mechanisms of disease pathogenesis. PMID:22240481

  20. Diminished L-arginine bioavailability in hypertension.

    PubMed

    Moss, Monique B; Brunini, Tatiana M C; Soares De Moura, Roberto; Novaes Malagris, Lúcia E; Roberts, Norman B; Ellory, J Clive; Mann, Giovanni E; Mendes Ribeiro, Antônio C

    2004-10-01

    L-Arginine is the precursor of NO (nitric oxide), a key endogenous mediator involved in endothelium-dependent vascular relaxation and platelet function. Although the concentration of intracellular L-arginine is well above the Km for NO synthesis, in many cells and pathological conditions the transport of L-arginine is essential for NO production (L-arginine paradox). The present study was designed to investigate the modulation of L-arginine/NO pathway in systemic arterial hypertension. Transport of L-arginine into RBCs (red blood cells) and platelets, NOS (NO synthase) activity and amino acid profiles in plasma were analysed in hypertensive patients and in an animal model of hypertension. Influx of L-arginine into RBCs was mediated by the cationic amino acid transport systems y+ and y+L, whereas, in platelets, influx was mediated only via system y+L. Chromatographic analyses revealed higher plasma levels of L-arginine in hypertensive patients (175+/-19 micromol/l) compared with control subjects (137+/-8 micromol/l). L-Arginine transport via system y+L, but not y+, was significantly reduced in RBCs from hypertensive patients (60+/-7 micromol.l(-1).cells(-1).h(-1); n=16) compared with controls (90+/-17 micromol.l(-1).cells(-1).h(-1); n=18). In human platelets, the Vmax for L-arginine transport via system y+L was 86+/-17 pmol.10(9) cells(-1).min(-1) in controls compared with 36+/-9 pmol.10(9) cells(-1).min(-1) in hypertensive patients (n=10; P<0.05). Basal NOS activity was decreased in platelets from hypertensive patients (0.12+/-0.02 pmol/10(8) cells; n=8) compared with controls (0.22+/-0.01 pmol/10(8) cells; n=8; P<0.05). Studies with spontaneously hypertensive rats demonstrated that transport of L-arginine via system y+L was also inhibited in RBCs. Our findings provide the first evidence that hypertension is associated with an inhibition of L-arginine transport via system y+L in both humans and animals, with reduced availability of L-arginine limiting NO synthesis in blood cells.

  1. Constant change: dynamic regulation of membrane transport by calcium signalling networks keeps plants in tune with their environment.

    PubMed

    Kleist, Thomas J; Luan, Sheng

    2016-03-01

    Despite substantial variation and irregularities in their environment, plants must conform to spatiotemporal demands on the molecular composition of their cytosol. Cell membranes are the major interface between organisms and their environment and the basis for controlling the contents and intracellular organization of the cell. Membrane transport proteins (MTPs) govern the flow of molecules across membranes, and their activities are closely monitored and regulated by cell signalling networks. By continuously adjusting MTP activities, plants can mitigate the effects of environmental perturbations, but effective implementation of this strategy is reliant on precise coordination among transport systems that reside in distinct cell types and membranes. Here, we examine the role of calcium signalling in the coordination of membrane transport, with an emphasis on potassium transport. Potassium is an exceptionally abundant and mobile ion in plants, and plant potassium transport has been intensively studied for decades. Classic and recent studies have underscored the importance of calcium in plant environmental responses and membrane transport regulation. In reviewing recent advances in our understanding of the coding and decoding of calcium signals, we highlight established and emerging roles of calcium signalling in coordinating membrane transport among multiple subcellular locations and distinct transport systems in plants, drawing examples from the CBL-CIPK signalling network. By synthesizing classical studies and recent findings, we aim to provide timely insights on the role of calcium signalling networks in the modulation of membrane transport and its importance in plant environmental responses. © 2015 John Wiley & Sons Ltd.

  2. Application of rain scanner SANTANU and transportable weather radar in analyze of Mesoscale Convective System (MCS) events over Bandung, West Java

    NASA Astrophysics Data System (ADS)

    Nugroho, G. A.; Sinatra, T.; Trismidianto; Fathrio, I.

    2018-05-01

    Simultaneous observation of transportable weather radar LAPAN-GMR25SP and rain-scanner SANTANU were conducted in Bandung and vicinity. The objective is to observe and analyse the weather condition in this area during rainy and transition season from March until April 2017. From the observation result reported some heavy rainfall with hail and strong winds occurred on March 17th and April 19th 2017. This events were lasted within 1 to 2 hours damaged some properties and trees in Bandung. Mesoscale convective system (MCS) are assumed to be the cause of this heavy rainfall. From two radar data analysis showed a more local convective activity in around 11.00 until 13.00 LT. This local convective activity are showed from the SANTANU observation supported by the VSECT and CMAX of the Transportable radar data that signify the convective activity within those area. MCS activity were observed one hour after that. This event are confirm by the classification of convective-stratiform echoes from radar data and also from the high convective index from Tbb Himawari 8 satellite data. The different MCS activity from this two case study is that April 19 have much more MCS activity than in March 17, 2017.

  3. [The specific features of the blood gas transport system in patients with postinfarction cardiosclerosis].

    PubMed

    Mikashinovich, Z I; Suroedova, R A; Olempieva, E V

    2009-10-01

    The specific features of blood gas transport system functioning were analyzed in patients with cardiovascular diseases. In patients with postinfarction cardiosclerosis (PICS), the quantitative mechanism for hypoxia adaptation tended to decrease, which may be considered to be a compensatory-adaptive reaction aimed at eliminating the sludge phenomenon and improving the rheological characteristics of blood. Acute myocardial reinfarction developed in patents with PICS is characterized by the lower functional activity of red blood cells, and developing hypoxia is an important link of activation of apoptotic cell death. The degree of hypoxia may be believed to correlate with the sizes of a myocardial necrosis focus.

  4. Preface: cardiac control pathways: signaling and transport phenomena.

    PubMed

    Sideman, Samuel

    2008-03-01

    Signaling is part of a complex system of communication that governs basic cellular functions and coordinates cellular activity. Transfer of ions and signaling molecules and their interactions with appropriate receptors, transmembrane transport, and the consequent intracellular interactions and functional cellular response represent a complex system of interwoven phenomena of transport, signaling, conformational changes, chemical activation, and/or genetic expression. The well-being of the cell thus depends on a harmonic orchestration of all these events and the existence of control mechanisms that assure the normal behavior of the various parameters involved and their orderly expression. The ability of cells to sustain life by perceiving and responding correctly to their microenvironment is the basis for development, tissue repair, and immunity, as well as normal tissue homeostasis. Natural deviations, or human-induced interference in the signaling pathways and/or inter- and intracellular transport and information transfer, are responsible for the generation, modulation, and control of diseases. The present overview aims to highlight some major topics of the highly complex cellular information transfer processes and their control mechanisms. Our goal is to contribute to the understanding of the normal and pathophysiological phenomena associated with cardiac functions so that more efficient therapeutic modalities can be developed. Our objective in this volume is to identify and enhance the study of some basic passive and active physical and chemical transport phenomena, physiological signaling pathways, and their biological consequences.

  5. Regulation of Nitrate Transport in Citrus Rootstocks Depending on Nitrogen Availability

    PubMed Central

    Cerezo, Miguel; Camañes, Gemma; Flors, Víctor; Primo-Millo, Eduardo

    2007-01-01

    Previously, we reported that in Citrus plants, nitrate influx through the plasmalemma of roots cells follows a biphasic pattern, suggesting the existence of at least two different uptake systems, a high and low affinity transport system (HATS and LATS, respectively). Here, we describe a novel inducible high affinity transport system (iHATS). This new nitrate transport system has a high capacity to uptake nitrate in two different Citrus rootstocks (Cleopatra mandarin and Troyer citrange). The iHATS was saturable, showing higher affinity than constitutive high affinity transport system (cHATS) to the substrate NO3−. The Vmax for this saturable component iHATS was higher than cHATS, reaching similar values in both rootstocks. Additionally, we studied the regulation of root NO3− uptake mediated by both HATS (iHATS and cHATS) and LATS. In both rootstocks, cHATS is constitutive and independent of N-status. Concerning the regulation of iHATS, this system is upregulated by NO3− and down-regulated by the N status and by NO3− itself when plants are exposed to it for a longer period of time. LATS in Cleopatra mandarin and Troyer citrange rootstocks is repressed by the N-status. The use of various metabolic uncouplers or inhibitors indicated that NO3− net uptake mediated by iHATS and LATS was an active transport system in both rootstocks. PMID:19516998

  6. Lunar base thermal management/power system analysis and design

    NASA Technical Reports Server (NTRS)

    Mcghee, Jerry R.

    1992-01-01

    A compilation of several lunar surface thermal management and power system studies completed under contract and IR&D is presented. The work includes analysis and preliminary design of all major components of an integrated thermal management system, including loads determination, active internal acquisition and transport equipment, external transport systems (active and passive), passive insulation, solar shielding, and a range of lunar surface radiator concepts. Several computer codes were utilized in support of this study, including RADSIM to calculate radiation exchange factors and view factors, RADIATOR (developed in-house) for heat rejection system sizing and performance analysis over a lunar day, SURPWER for power system sizing, and CRYSTORE for cryogenic system performance predictions. Although much of the work was performed in support of lunar rover studies, any or all of the results can be applied to a range of surface applications. Output data include thermal loads summaries, subsystem performance data, mass, and volume estimates (where applicable), integrated and worst-case lunar day radiator size/mass and effective sink temperatures for several concepts (shielded and unshielded), and external transport system performance estimates for both single and two-phase (heat pumped) transport loops. Several advanced radiator concepts are presented, along with brief assessments of possible system benefits and potential drawbacks. System point designs are presented for several cases, executed in support of the contract and IR&D studies, although the parametric nature of the analysis is stressed to illustrate applicability of the analysis procedure to a wide variety of lunar surface systems. The reference configuration(s) derived from the various studies will be presented along with supporting criteria. A preliminary design will also be presented for the reference basing scenario, including qualitative data regarding TPS concerns and issues.

  7. Next generation: In-space transportation system(s)

    NASA Technical Reports Server (NTRS)

    Huffaker, Fredrick; Redus, Jerry; Kelley, David L.

    1991-01-01

    The development of the next generation In-Space Transportation System presents a unique challenge to the design of a propulsion system for the Space Exploration Initiative (SEI). Never before have the requirements for long-life, multiple mission use, space basing, high reliability, man-rating, and minimum maintenance come together with performance in one system that must protect the lives of space travelers, support the mission logistics needs, and do so at an acceptable cost. The challenge that is presented is to quantify the bounds of these requirements. The issue is one of degree. The length of acceptable life in space, the time it takes for reuse to pay off, and the degree to which space basing is practical (full, partial, or expended) are the issues that determine the reusable bounds of a design and include dependability, contingency capabilities, resilency, and minimum dependence on a maintenance node in preparation for and during a mission. Missions to planet earth, other non-NASA missions, and planetary missions will provide important but less demanding requirements for the transportation systems of the future. The mission proposed for the SEI require a family of transportation vehicles to meet the requirements for establishing a permanent human presence on the Moon and eventually on Mars. Specialized vehicles are needed to accomplish the different phases of each mission. These large scale missions require assembly in space and will provide the greatest usage of the planned integrated transportation system. The current approach to defining the In-Space Transportation System for the SEI Moon missions with later Mars mission applications is presented. Several system development options, propulsion concepts, current/proposed activities are reviewed, and key propulsion design criteria, issues, and technology challenges for the next generation In-Space Transportation System(s) are outlined.

  8. Steps for action : getting intelligent transportation systems ready for the year 2000

    DOT National Transportation Integrated Search

    1999-01-01

    This brochure is addressed to the U.S. Department of Transportation's (DOT's) public- and private-sector partners. It's purpose is to serve as an organizing tool that will help map out Y2K problem-solving activities between now and January 1, 2000. I...

  9. Afstemming Questa-Factoren en Scenario Verkenner 1.2 : deel 3, vervoerprestaties personenvervoer.

    DOT National Transportation Integrated Search

    1999-09-01

    The Questa project is an activity of the Ministry of Transport and Public Works and aims to develop a long term view on developments in society and their impacts on the traffic and transport system. Four scenarios are evaluated for a timescale up to ...

  10. Forecasting the impacts of shale gas developments on public health and transportation systems on both sides of the Mexico-U.S. border.

    DOT National Transportation Integrated Search

    2015-08-01

    The activities completed for this project includes the literature research on the Eagle Ford formation, the review : of public-health and transportation related variables to shale gas developments, and the definition of the project : collaborative si...

  11. A COMPUTER-CONTROLLED SYSTEM FOR GENERATING UNIFORM SURFACE DEPOSITS TO STUDY THE TRANSPORT OF PARTICULATE MATTER

    EPA Science Inventory

    Improved methods for measuring and assessing microenvironmental exposure in individuals are needed. How human activities affect particulate matter in the personal cloud is poorly understood. A quality assurance tool to aid the study of particle transport mechanisms (e.g., re-en...

  12. Expression of apical Na(+)-L-glutamine co-transport activity, B(0)-system neutral amino acid co-transporter (B(0)AT1) and angiotensin-converting enzyme 2 along the jejunal crypt-villus axis in young pigs fed a liquid formula.

    PubMed

    Yang, Chengbo; Yang, Xiaojian; Lackeyram, Dale; Rideout, Todd C; Wang, Zirong; Stoll, Barbara; Yin, Yulong; Burrin, Douglas G; Fan, Ming Z

    2016-06-01

    Gut apical amino acid (AA) transport activity is high at birth and during suckling, thus being essential to maintain luminal nutrient-dependent mucosal growth through providing AA as essential metabolic fuel, substrates and nutrient stimuli for cellular growth. Because system-B(0) Na(+)-neutral AA co-transporter (B(0)AT1, encoded by the SLC6A19 gene) plays a dominant role for apical uptake of large neutral AA including L-Gln, we hypothesized that high apical Na(+)-Gln co-transport activity, and B(0)AT1 (SLC6A19) in co-expression with angiotensin-converting enzyme 2 (ACE2) were expressed along the entire small intestinal crypt-villus axis in young animals via unique control mechanisms. Kinetics of Na(+)-Gln co-transport activity in the apical membrane vesicles, prepared from epithelial cells sequentially isolated along the jejunal crypt-villus axis from liquid formula-fed young pigs, were measured with the membrane potential being clamped to zero using thiocyanate. Apical maximal Na(+)-Gln co-transport activity was much higher (p < 0.05) in the upper villus cells than in the middle villus (by 29 %) and the crypt (by 30 %) cells, whereas Na(+)-Gln co-transport affinity was lower (p < 0.05) in the upper villus cells than in the middle villus and the crypt cells. The B(0)AT1 (SLC6A19) mRNA abundance was lower (p < 0.05) in the crypt (by 40-47 %) than in the villus cells. There were no significant differences in B(0)AT1 and ACE2 protein abundances on the apical membrane among the upper villus, the middle villus and the crypt cells. Our study suggests that piglet fast growth is associated with very high intestinal apical Na(+)-neutral AA uptake activities via abundantly co-expressing B(0)AT1 and ACE2 proteins in the apical membrane and by transcribing the B(0)AT1 (SLC6A19) gene in the epithelia along the entire crypt-villus axis.

  13. Physical activity patterns among Latinos in the United States: putting the pieces together.

    PubMed

    Ham, Sandra A; Yore, Michelle M; Kruger, Judy; Heath, Gregory W; Moeti, Refilwe

    2007-10-01

    Estimates of participation in physical activity among Latinos are inconsistent across studies. To obtain better estimates and examine possible reasons for inconsistencies, we assessed 1) patterns of participation in various categories of physical activity among Latino adults, 2) changes in their activity patterns with acculturation, and 3) variations in their activity patterns by region of origin. Using data from four national surveillance systems (the National Health and Nutrition Examination Survey, 1999-2002; the Behavioral Risk Factor Surveillance System, 2003; the National Household Travel Survey, 2001; and the National Health Interview Survey Cancer Supplement, 2000), we estimated the percentage of Latinos who participated at least once per week in leisure-time, household, occupational, or transportation-related physical activity, as well as in an active pattern of usual daily activity. We reported prevalences by acculturation measures and region of origin. The percentage of Latinos who participated in the various types of physical activity ranged from 28.7% for having an active level of usual daily activity (usually walking most of the day and usually carrying or lifting objects) to 42.8% for participating in leisure-time physical activity at least once per week. The percentage who participated in leisure-time and household activities increased with acculturation, whereas the percentage who participated in occupational and transportation-related activities decreased with acculturation. Participation in an active level of usual daily activity did not change significantly. The prevalence of participation in transportation-related physical activity and of an active level of usual daily activity among Latino immigrants varied by region of origin. Physical activity patterns among Latinos vary with acculturation and region of origin. To assess physical activity levels in Latino communities, researchers should measure all types of physical activity and the effects of acculturation on each type of activity.

  14. Materials Genomics Screens for Adaptive Ion Transport Behavior by Redox-Switchable Microporous Polymer Membranes in Lithium-Sulfur Batteries.

    PubMed

    Ward, Ashleigh L; Doris, Sean E; Li, Longjun; Hughes, Mark A; Qu, Xiaohui; Persson, Kristin A; Helms, Brett A

    2017-05-24

    Selective ion transport across membranes is critical to the performance of many electrochemical energy storage devices. While design strategies enabling ion-selective transport are well-established, enhancements in membrane selectivity are made at the expense of ionic conductivity. To design membranes with both high selectivity and high ionic conductivity, there are cues to follow from biological systems, where regulated transport of ions across membranes is achieved by transmembrane proteins. The transport functions of these proteins are sensitive to their environment: physical or chemical perturbations to that environment are met with an adaptive response. Here we advance an analogous strategy for achieving adaptive ion transport in microporous polymer membranes. Along the polymer backbone are placed redox-active switches that are activated in situ, at a prescribed electrochemical potential, by the device's active materials when they enter the membrane's pore. This transformation has little influence on the membrane's ionic conductivity; however, the active-material blocking ability of the membrane is enhanced. We show that when used in lithium-sulfur batteries, these membranes offer markedly improved capacity, efficiency, and cycle-life by sequestering polysulfides in the cathode. The origins and implications of this behavior are explored in detail and point to new opportunities for responsive membranes in battery technology development.

  15. Materials Genomics Screens for Adaptive Ion Transport Behavior by Redox-Switchable Microporous Polymer Membranes in Lithium–Sulfur Batteries

    PubMed Central

    2017-01-01

    Selective ion transport across membranes is critical to the performance of many electrochemical energy storage devices. While design strategies enabling ion-selective transport are well-established, enhancements in membrane selectivity are made at the expense of ionic conductivity. To design membranes with both high selectivity and high ionic conductivity, there are cues to follow from biological systems, where regulated transport of ions across membranes is achieved by transmembrane proteins. The transport functions of these proteins are sensitive to their environment: physical or chemical perturbations to that environment are met with an adaptive response. Here we advance an analogous strategy for achieving adaptive ion transport in microporous polymer membranes. Along the polymer backbone are placed redox-active switches that are activated in situ, at a prescribed electrochemical potential, by the device’s active materials when they enter the membrane’s pore. This transformation has little influence on the membrane’s ionic conductivity; however, the active-material blocking ability of the membrane is enhanced. We show that when used in lithium–sulfur batteries, these membranes offer markedly improved capacity, efficiency, and cycle-life by sequestering polysulfides in the cathode. The origins and implications of this behavior are explored in detail and point to new opportunities for responsive membranes in battery technology development. PMID:28573201

  16. Using fluorometry and ion-sensitive microelectrodes to study the functional expression of heterologously-expressed ion channels and transporters in Xenopus oocytes

    PubMed Central

    Musa-Aziz, Raif; Boron, Walter F.; Parker, Mark D.

    2010-01-01

    The Xenopus laevis oocyte is a model system for the electrophysiological study of exogenous ion transporters. Three main reasons make the oocyte suitable for this purpose: (a) it has a large cell size (~1 mm diameter), (b) it has an established capacity to produce—from microinjected mRNAs or cRNAs—exogenous ion transporters with close-to-physiological post-translational modifications and actions, and (c) its membranes contain endogenous ion-transport activities which are usually smaller in magnitude than the activities of exogenously-expressed ion transporters. The expression of ion-transporters as green-fluorescent-protein fusions allows the fluorometric assay of transporter yield in living oocytes. Monitoring of transporter-mediated movement of ions such as Cl−, H+ (and hence base equivalents like OH−1 and HCO3−), K+, and Na+ is achieved by positioning the tips of ion-sensitive microelectrodes inside the oocyte and/or at the surface of the oocyte plasma membrane. The use of ion-sensitive electrodes is critical for studying net ion-movements mediated by electroneutral transporters. The combined use of fluorometry and electrophysiology expedites transporter study by allowing measurement of transporter yield prior to electrophysiological study and correlation of relative transporter yield with transport rates. PMID:20051266

  17. Effective equations governing an active poroelastic medium

    PubMed Central

    2017-01-01

    In this work, we consider the spatial homogenization of a coupled transport and fluid–structure interaction model, to the end of deriving a system of effective equations describing the flow, elastic deformation and transport in an active poroelastic medium. The ‘active’ nature of the material results from a morphoelastic response to a chemical stimulant, in which the growth time scale is strongly separated from other elastic time scales. The resulting effective model is broadly relevant to the study of biological tissue growth, geophysical flows (e.g. swelling in coals and clays) and a wide range of industrial applications (e.g. absorbant hygiene products). The key contribution of this work is the derivation of a system of homogenized partial differential equations describing macroscale growth, coupled to transport of solute, that explicitly incorporates details of the structure and dynamics of the microscopic system, and, moreover, admits finite growth and deformation at the pore scale. The resulting macroscale model comprises a Biot-type system, augmented with additional terms pertaining to growth, coupled to an advection–reaction–diffusion equation. The resultant system of effective equations is then compared with other recent models under a selection of appropriate simplifying asymptotic limits. PMID:28293138

  18. The Transportable Applications Environment - An interactive design-to-production development system

    NASA Technical Reports Server (NTRS)

    Perkins, Dorothy C.; Howell, David R.; Szczur, Martha R.

    1988-01-01

    An account is given of the design philosophy and architecture of the Transportable Applications Environment (TAE), an executive program binding a system of applications programs into a single, easily operable whole. TAE simplifies the job of a system developer by furnishing a stable framework for system-building; it also integrates system activities, and cooperates with the host operating system in order to perform such functions as task-scheduling and I/O. The initial TAE human/computer interface supported command and menu interfaces, data displays, parameter-prompting, error-reporting, and online help. Recent extensions support graphics workstations with a window-based, modeless user interface.

  19. Blockade of Y177 and Nuclear Translocation of Bcr-Abl Inhibits Proliferation and Promotes Apoptosis in Chronic Myeloid Leukemia Cells.

    PubMed

    Li, Qianyin; Huang, Zhenglan; Gao, Miao; Cao, Weixi; Xiao, Qin; Luo, Hongwei; Feng, Wenli

    2017-03-02

    The gradual emerging of resistance to imatinib urgently calls for the development of new therapy for chronic myeloid leukemia (CML). The fusion protein Bcr-Abl, which promotes the malignant transformation of CML cells, is mainly located in the cytoplasm, while the c-Abl protein which is expressed in the nucleus can induce apoptosis. Based on the hetero-dimerization of FKBP (the 12-kDa FK506- and rapamycin-binding protein) and FRB (the FKBP-rapamycin binding domain of the protein kinase, mTOR) mediated by AP21967, we constructed a nuclear transport system to induce cytoplasmic Bcr-Abl into nuclear. In this study, we reported the construction of the nuclear transport system, and we demonstrated that FN3R (three nuclear localization signals were fused to FRBT2098L with a FLAG tag), HF2S (two FKBP domains were in tandem and fused to the SH2 domain of Grb2 with an HA tag) and Bcr-Abl form a complexus upon AP21967. Bcr-Abl was imported into the nucleus successfully by the nuclear transport system. The nuclear transport system inhibited CML cell proliferation through mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 5 (STAT5) pathways mainly by HF2S. It was proven that nuclear located Bcr-Abl induced CML cell (including imatinib-resistant K562G01 cells) apoptosis by activation of p73 and its downstream molecules. In summary, our study provides a new targeted therapy for the CML patients even with Tyrosine Kinase Inhibitor (TKI)-resistance.

  20. Theory of activated transport in bilayer quantum Hall systems.

    PubMed

    Roostaei, B; Mullen, K J; Fertig, H A; Simon, S H

    2008-07-25

    We analyze the transport properties of bilayer quantum Hall systems at total filling factor nu=1 in drag geometries as a function of interlayer bias, in the limit where the disorder is sufficiently strong to unbind meron-antimeron pairs, the charged topological defects of the system. We compute the typical energy barrier for these objects to cross incompressible regions within the disordered system using a Hartree-Fock approach, and show how this leads to multiple activation energies when the system is biased. We then demonstrate using a bosonic Chern-Simons theory that in drag geometries current in a single layer directly leads to forces on only two of the four types of merons, inducing dissipation only in the drive layer. Dissipation in the drag layer results from interactions among the merons, resulting in very different temperature dependences for the drag and drive layers, in qualitative agreement with experiment.

  1. Electrocardiographic Indicators of Acute Coronary Syndrome are More Common in Patients with Ambulance Transport Compared to Those who Self-Transport to the Emergency Department Journal of Electrocardiology

    PubMed Central

    Pickham, David; Pelter, Michele M

    2016-01-01

    Introduction The American Heart Association recommends individuals with symptoms suggestive of acute coronary syndrome (ACS) activate the Emergency Medical Services’ (EMS) 911 system for ambulance transport to the emergency department (ED), which enables treatment to begin prior to hospital arrival. Despite this recommendation, the majority of patients with symptoms suspicious of ACS continue to self-transport to the ED. The IMMEDIATE AIM study was a prospective study that enrolled individuals who presented to the ED with ischemic symptoms. Objectives The purpose of this secondary analysis was to determine differences in patients presenting the ED for possible ACS who arrive by ambulance versus self-transport on: 1) Time-to-initial hospital electrocardiogram (ECG), 2) presence of ischemic ECG changes, and 3) patient characteristics. Methods Initial 12-lead ECGs acquired upon patient arrival to the ED were evaluated for ST-elevation, ST-depression, and T-wave inversion. ECG signs of ischemia were analyzed both individually and collapsed into an independent dichotomous variable (ED ECG ischemia yes/no) for statistical analysis. Patient characteristics tested included: gender, age, race, ethnicity, English speaking, living alone, mode of transport, and presenting symptoms (chest pain, jaw pain, shortness of breath, nausea/vomiting, syncope, and clinical history). Results In 1299 patients (mean age 63.9, 46.7% male), 384 (29.6%) patients arrived by ambulance to the ED. The mean time-to-initial ECG was 47 minutes for ambulance patients versus 53 minutes for self-transport patients (p<0.001). Mode of transport was found to be an independent predictor for time-to-initial ECG controlling for age, gender, and race (p=0.004). There were significantly higher rates of ECG changes of ischemia for patients who arrived by ambulance versus self-transport (p=0.02), and patient characteristics differed by mode of transport to the ED. Discussion Our findings indicate that less than 30% of individuals with symptoms of ACS activate the EMS ‘911’ system for ambulance transport to the ED. Individuals more likely to activate 911 have timelier ECG but higher rates of ischemic changes, specifically ST-depression and T-wave inversion. Individuals least likely to activate 911 are women, younger individuals, Latino ethnicity, live with a significant other, and those experiencing chest or jaw pain. PMID:27614946

  2. Nitrate transport in the cyanobacterium Anacystis nidulans R2. Kinetic and energetic aspects.

    PubMed Central

    Rodríguez, R; Lara, C; Guerrero, M G

    1992-01-01

    Nitrate transport has been studied in the cyanobacterium Anacystis nidulans R2 by monitoring intracellular nitrate accumulation in intact cells of the mutant strain FM6, which lacks nitrate reductase activity and is therefore unable to reduce the transported nitrate. Kinetic analysis of nitrate transport as a function of external nitrate concentration revealed apparent substrate inhibition, with a peak velocity at 20-25 microM-nitrate. A Ks (NO3-) of 1 microM was calculated. Nitrate transport exhibited a stringent requirement for Na+. Neither Li+ nor K+ could substitute for Na+. Monensin depressed nitrate transport in a concentration-dependent manner, inhibition being more than 60% at 2 microM, indicating that the Na(+)-dependence of active nitrate transport relies on the maintenance of a Na+ electrochemical gradient. The operation of an Na+/NO3- symport system is suggested. Nitrite behaved as an effective competitive inhibitor of nitrate transport, with a Ki (NO2-) of 3 microM. The time course of nitrite inhibition of nitrate transport was consistent with competitive inhibition by mixed alternative substrates. Nitrate and nitrite might be transported by the same carrier. PMID:1554347

  3. [Transportation and transformation of 14C-phenanthrene in closed chamber (nutrient solution-lava-plant-air) system].

    PubMed

    Jiang, X; Ou, Z; Ying, P; Yediler, A; Ketrrup, A

    2001-06-01

    The transportation and transformation of 14C-phenanthrene in a closed 'plant-lava-nutrient solution-air' chamber system was studied by using radioactivity technology. The results showed that in this closed chamber system, phenanthrene was degraded fast. The radioactivity of 14C left at 23d in the nutrient solution was only 25% of applied. At the end of experiment (46d), the distribution sequence of 14C activity in the components of closed chamber system was root (38.55%) > volatile organic compounds (VOCs, 17.68%) > lava (14.35%) > CO2 (11.42%) > stem (2%). 14C-activities in plant tissue were combined with the tissue, and existed in the forms of lava-bound(root 4.68%; stem and leaves 0.68%) and polar metabolites (root 23.14%; stem 0.78%).

  4. Hydrocyclonic separation of invasive New Zealand mudsnails from an aquaculture water source

    USGS Publications Warehouse

    Nielson, R. Jordan; Moffitt, Christine M.; Watten, Barnaby J.

    2012-01-01

    Invasive New Zealand mudsnails (Potamopyrgus antipodarum, NZMS) have infested freshwater aquaculture facilities in the western United States and disrupted stocking or fish transportation activities because of the risk of transporting NZMS to naive locations. We tested the efficacy of a gravity-fed, hydrocyclonicseparation system to remove NZMS from an aquaculture water source at two design flows: 367 L/min and 257 L/min. The hydrocyclone effectively filtered all sizes of snails (including newly emerged neonates) from inflows. We modeled cumulative recovery of three sizes of snails, and determined that both juvenile and adult sized snails were transported similarly through the filtration system, but the transit of neonates was faster and similar to the transport of water particles. We found that transit times through the filtration system were different between the two flows regardless of snail size, and the hydrocyclone filter operated more as a plug flow system with dispersion, especially when transporting and removing the larger sized adult and juvenile sized snails. Our study supports hydrocyclonic filtration as an important tool to provide snail free water for aquaculture operations that require uninfested water sources.

  5. A systems approach to hemostasis: 3. Thrombus consolidation regulates intrathrombus solute transport and local thrombin activity

    PubMed Central

    Welsh, John D.; Tomaiuolo, Maurizio; Wu, Jie; Colace, Thomas V.; Diamond, Scott L.

    2014-01-01

    Hemostatic thrombi formed after a penetrating injury have a distinctive structure in which a core of highly activated, closely packed platelets is covered by a shell of less-activated, loosely packed platelets. We have shown that differences in intrathrombus molecular transport emerge in parallel with regional differences in platelet packing density and predicted that these differences affect thrombus growth and stability. Here we test that prediction in a mouse vascular injury model. The studies use a novel method for measuring thrombus contraction in vivo and a previously characterized mouse line with a defect in integrin αIIbβ3 outside-in signaling that affects clot retraction ex vivo. The results show that the mutant mice have a defect in thrombus consolidation following vascular injury, resulting in an increase in intrathrombus transport rates and, as predicted by computational modeling, a decrease in thrombin activity and platelet activation in the thrombus core. Collectively, these data (1) demonstrate that in addition to the activation state of individual platelets, the physical properties of the accumulated mass of adherent platelets is critical in determining intrathrombus agonist distribution and platelet activation and (2) define a novel role for integrin signaling in the regulation of intrathrombus transport rates and localization of thrombin activity. PMID:24951426

  6. Structural specificity of mucosal-cell transport and metabolism of peptide drugs: implication for oral peptide drug delivery

    NASA Technical Reports Server (NTRS)

    Bai, J. P.; Amidon, G. L.

    1992-01-01

    The brush border membrane of intestinal mucosal cells contains a peptide carrier system with rather broad substrate specificity and various endo- and exopeptidase activities. Small peptide (di-/tripeptide)-type drugs with or without an N-terminal alpha-amino group, including beta-lactam antibiotics and angiotensin-converting enzyme (ACE) inhibitors, are transported by the peptide transporter. Polypeptide drugs are hydrolyzed by brush border membrane proteolytic enzymes to di-/tripeptides and amino acids. Therefore, while the intestinal brush border membrane has a carrier system facilitating the absorption of di-/tripeptide drugs, it is a major barrier limiting oral availability of polypeptide drugs. In this paper, the specificity of peptide transport and metabolism in the intestinal brush border membrane is reviewed.

  7. Central role of the observable electric potential in transport equations.

    PubMed

    Garrido, J; Compañ, V; López, M L

    2001-07-01

    Nonequilibrium systems are usually studied in the framework of transport equations that involve the true electric potential (TEP), a nonobservable variable. Nevertheless another electric potential, the observable electric potential (OEP), may be defined to construct a useful set of transport equations. In this paper several basic characteristics of the OEP are deduced and emphasized: (i) the OEP distribution depends on thermodynamic state of the solution, (ii) the observable equations have a reference value for all other transport equations, (iii) the bridge that connects the OEP with a certain TEP is usually defined by the ion activity coefficient, (iv) the electric charge density is a nonobservable variable, and (v) the OEP formulation constitutes a natural model for studying the fluxes in membrane systems.

  8. The Endoplasmic Reticulum Coat Protein II Transport Machinery Coordinates Cellular Lipid Secretion and Cholesterol Biosynthesis*

    PubMed Central

    Fryer, Lee G. D.; Jones, Bethan; Duncan, Emma J.; Hutchison, Claire E.; Ozkan, Tozen; Williams, Paul A.; Alder, Olivia; Nieuwdorp, Max; Townley, Anna K.; Mensenkamp, Arjen R.; Stephens, David J.; Dallinga-Thie, Geesje M.; Shoulders, Carol C.

    2014-01-01

    Triglycerides and cholesterol are essential for life in most organisms. Triglycerides serve as the principal energy storage depot and, where vascular systems exist, as a means of energy transport. Cholesterol is essential for the functional integrity of all cellular membrane systems. The endoplasmic reticulum is the site of secretory lipoprotein production and de novo cholesterol synthesis, yet little is known about how these activities are coordinated with each other or with the activity of the COPII machinery, which transports endoplasmic reticulum cargo to the Golgi. The Sar1B component of this machinery is mutated in chylomicron retention disorder, indicating that this Sar1 isoform secures delivery of dietary lipids into the circulation. However, it is not known why some patients with chylomicron retention disorder develop hepatic steatosis, despite impaired intestinal fat malabsorption, and why very severe hypocholesterolemia develops in this condition. Here, we show that Sar1B also promotes hepatic apolipoprotein (apo) B lipoprotein secretion and that this promoting activity is coordinated with the processes regulating apoB expression and the transfer of triglycerides/cholesterol moieties onto this large lipid transport protein. We also show that although Sar1A antagonizes the lipoprotein secretion-promoting activity of Sar1B, both isoforms modulate the expression of genes encoding cholesterol biosynthetic enzymes and the synthesis of cholesterol de novo. These results not only establish that Sar1B promotes the secretion of hepatic lipids but also adds regulation of cholesterol synthesis to Sar1B's repertoire of transport functions. PMID:24338480

  9. An integrated field-effect microdevice for monitoring membrane transport in Xenopus laevis oocytes via lateral proton diffusion.

    PubMed

    Schaffhauser, Daniel Felix; Patti, Monica; Goda, Tatsuro; Miyahara, Yuji; Forster, Ian Cameron; Dittrich, Petra Stephanie

    2012-01-01

    An integrated microdevice for measuring proton-dependent membrane activity at the surface of Xenopus laevis oocytes is presented. By establishing a stable contact between the oocyte vitelline membrane and an ion-sensitive field-effect (ISFET) sensor inside a microperfusion channel, changes in surface pH that are hypothesized to result from facilitated proton lateral diffusion along the membrane were detected. The solute diffusion barrier created between the sensor and the active membrane area allowed detection of surface proton concentration free from interference of solutes in bulk solution. The proposed sensor mechanism was verified by heterologously expressing membrane transport proteins and recording changes in surface pH during application of the specific substrates. Experiments conducted on two families of phosphate-sodium cotransporters (SLC20 & SLC34) demonstrated that it is possible to detect phosphate transport for both electrogenic and electroneutral isoforms and distinguish between transport of different phosphate species. Furthermore, the transport activity of the proton/amino acid cotransporter PAT1 assayed using conventional whole cell electrophysiology correlated well with changes in surface pH, confirming the ability of the system to detect activity proportional to expression level.

  10. Analogies between respiration and a light-driven proton pump as sources of energy for active glutamate transport in Halobacterium halobium

    NASA Technical Reports Server (NTRS)

    Belliveau, J. W.; Lanyi, J. K.

    1977-01-01

    Halobacterium halobium is known to contain sheets of bacteriorhodopsin, a pigment which upon exposure to light undergoes cyclic protonation and deprotonation, resulting in net H(+) translocation. In this paper, experiments were conducted to test H. halobium cell envelope vesicles for respiration-induced glutamate uptake. It is shown that glutamate transport in H. halobium cell envelope vesicles can occur as a result of respiration, as well as light acting on bacteriorhodopsin. Glutamate transport can be energized by the oxidation of dimethyl phenylenediamine, and the properties of the transport system are entirely analogous to those observed with illumination as the source of energy. In the case of respiration-dependent glutamate transport, the transportation is also driven by a Na(+) gradient, thereby confirming the existence of a single glutamate transport system independent of the source of energy. The analogy observed is indirect evidence that the cytochrome oxidase of H. halobium functions as a H(+) pump.

  11. Lockheed laminar-flow control systems development and applications

    NASA Technical Reports Server (NTRS)

    Lange, Roy H.

    1987-01-01

    Progress is summarized from 1974 to the present in the practical application of laminar-flow control (LFC) to subsonic transport aircraft. Those efforts included preliminary design system studies of commercial and military transports and experimental investigations leading to the development of the leading-edge flight test article installed on the NASA JetStar flight test aircraft. The benefits of LFC on drag, fuel efficiency, lift-to-drag ratio, and operating costs are compared with those for turbulent flow aircraft. The current activities in the NASA Industry Laminar-Flow Enabling Technologies Development contract include summaries of activities in the Task 1 development of a slotted-surface structural concept using advanced aluminum materials and the Task 2 preliminary conceptual design study of global-range military hybrid laminar flow control (HLFC) to obtain data at high Reynolds numbers and at Mach numbers representative of long-range subsonic transport aircraft operation.

  12. Sodium-coupled electrogenic transport of pyroglutamate (5-oxoproline) via SLC5A8, a monocarboxylate transporter.

    PubMed

    Miyauchi, Seiji; Gopal, Elangovan; Babu, Ellappan; Srinivas, Sonne R; Kubo, Yoshiyuki; Umapathy, Nagavedi S; Thakkar, Santoshanand V; Ganapathy, Vadivel; Prasad, Puttur D

    2010-06-01

    Pyroglutamate, also known as 5-oxoproline, is a structural analog of proline. This amino acid derivative is a byproduct of glutathione metabolism, and is reabsorbed efficiently in kidney by Na(+)-coupled transport mechanisms. Previous studies have focused on potential participation of amino acid transport systems in renal reabsorption of this compound. Here we show that it is not the amino acid transport systems but instead the Na(+)-coupled monocarboxylate transporter SLC5A8 that plays a predominant role in this reabsorptive process. Expression of cloned human and mouse SLC5A8 in mammalian cells induces Na(+)-dependent transport of pyroglutamate that is inhibitable by various SLC5A8 substrates. SLC5A8-mediated transport of pyroglutamate is saturable with a Michaelis constant of 0.36+/-0.04mM. Na(+)-activation of the transport process exhibits sigmoidal kinetics with a Hill coefficient of 1.8+/-0.4, indicating involvement of more than one Na(+) in the activation process. Expression of SLC5A8 in Xenopuslaevis oocytes induces Na(+)-dependent inward currents in the presence of pyroglutamate under voltage-clamp conditions. The concentration of pyroglutamate necessary for induction of half-maximal current is 0.19+/-0.01mM. The Na(+)-activation kinetics is sigmoidal with a Hill coefficient of 2.3+/-0.2. Ibuprofen, a blocker of SLC5A8, suppressed pyroglutamate-induced currents in SLC5A8-expressing oocytes; the concentration of the blocker necessary for causing half-maximal inhibition is 14+/-1microM. The involvement of SLC5A8 can be demonstrated in rabbit renal brush border membrane vesicles by showing that the Na(+)-dependent uptake of pyroglutamate in these vesicles is inhibitable by known substrates of SLC5A8. The Na(+) gradient-driven pyroglutamate uptake was stimulated by an inside-negative K(+) diffusion potential induced by valinomycin, showing that the uptake process is electrogenic.

  13. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Reichhardt, Cynthia Jane; Reichhardt, Charles

    Ratchet effects can arise for single or collectively interacting Brownian particles on an asymmetric substrate when a net dc transport is produced by an externally applied ac driving force or by periodically flashing the substrate. Recently, a new class of active ratchet systems that do not require the application of external driving has been realized through the use of active matter; they are self-propelled units that can be biological or nonbiological in nature. When active materials such as swimming bacteria interact with an asymmetric substrate, a net dc directed motion can arise even without external driving, opening a wealth ofmore » possibilities such as sorting, cargo transport, or micromachine construction. We review the current status of active matter ratchets for swimming bacteria, cells, active colloids, and swarming models, focusing on the role of particle-substrate interactions. Here, we describe ratchet reversals produced by collective effects and the use of active ratchets to transport passive particles. We discuss future directions including deformable substrates or particles, the role of different swimming modes, varied particle–particle interactions, and nondissipative effects.« less

  14. A sensory complex consisting of an ATP-binding cassette transporter and a two-component regulatory system controls bacitracin resistance in Bacillus subtilis.

    PubMed

    Dintner, Sebastian; Heermann, Ralf; Fang, Chong; Jung, Kirsten; Gebhard, Susanne

    2014-10-03

    Resistance against antimicrobial peptides in many Firmicutes bacteria is mediated by detoxification systems that are composed of a two-component regulatory system (TCS) and an ATP-binding cassette (ABC) transporter. The histidine kinases of these systems depend entirely on the transporter for sensing of antimicrobial peptides, suggesting a novel mode of signal transduction where the transporter constitutes the actual sensor. The aim of this study was to investigate the molecular mechanisms of this unusual signaling pathway in more detail, using the bacitracin resistance system BceRS-BceAB of Bacillus subtilis as an example. To analyze the proposed communication between TCS and the ABC transporter, we characterized their interactions by bacterial two-hybrid analyses and could show that the permease BceB and the histidine kinase BceS interact directly. In vitro pulldown assays confirmed this interaction, which was found to be independent of bacitracin. Because it was unknown whether BceAB-type transporters could detect their substrate peptides directly or instead recognized the peptide-target complex in the cell envelope, we next analyzed substrate binding by the transport permease, BceB. Direct and specific binding of bacitracin by BceB was demonstrated by surface plasmon resonance spectroscopy. Finally, in vitro signal transduction assays indicated that complex formation with the transporter influenced the autophosphorylation activity of the histidine kinase. Taken together, our findings clearly show the existence of a sensory complex composed of TCS and ABC transporters and provide the first functional insights into the mechanisms of stimulus perception, signal transduction, and antimicrobial resistance employed by Bce-like detoxification systems. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. A Sensory Complex Consisting of an ATP-binding Cassette Transporter and a Two-component Regulatory System Controls Bacitracin Resistance in Bacillus subtilis*

    PubMed Central

    Dintner, Sebastian; Heermann, Ralf; Fang, Chong; Jung, Kirsten; Gebhard, Susanne

    2014-01-01

    Resistance against antimicrobial peptides in many Firmicutes bacteria is mediated by detoxification systems that are composed of a two-component regulatory system (TCS) and an ATP-binding cassette (ABC) transporter. The histidine kinases of these systems depend entirely on the transporter for sensing of antimicrobial peptides, suggesting a novel mode of signal transduction where the transporter constitutes the actual sensor. The aim of this study was to investigate the molecular mechanisms of this unusual signaling pathway in more detail, using the bacitracin resistance system BceRS-BceAB of Bacillus subtilis as an example. To analyze the proposed communication between TCS and the ABC transporter, we characterized their interactions by bacterial two-hybrid analyses and could show that the permease BceB and the histidine kinase BceS interact directly. In vitro pulldown assays confirmed this interaction, which was found to be independent of bacitracin. Because it was unknown whether BceAB-type transporters could detect their substrate peptides directly or instead recognized the peptide-target complex in the cell envelope, we next analyzed substrate binding by the transport permease, BceB. Direct and specific binding of bacitracin by BceB was demonstrated by surface plasmon resonance spectroscopy. Finally, in vitro signal transduction assays indicated that complex formation with the transporter influenced the autophosphorylation activity of the histidine kinase. Taken together, our findings clearly show the existence of a sensory complex composed of TCS and ABC transporters and provide the first functional insights into the mechanisms of stimulus perception, signal transduction, and antimicrobial resistance employed by Bce-like detoxification systems. PMID:25118291

  16. Glucose transport in brain - effect of inflammation.

    PubMed

    Jurcovicova, J

    2014-01-01

    Glucose is transported across the cell membrane by specific saturable transport system, which includes two types of glucose transporters: 1) sodium dependent glucose transporters (SGLTs) which transport glucose against its concentration gradient and 2) sodium independent glucose transporters (GLUTs), which transport glucose by facilitative diffusion in its concentration gradient. In the brain, both types of transporters are present with different function, affinity, capacity, and tissue distribution. GLUT1 occurs in brain in two isoforms. The more glycosylated GLUT1 is produced in brain microvasculature and ensures glucose transport across the blood brain barrier (BBB). The less glycosylated form is localized in astrocytic end-feet and cell bodies and is not present in axons, neuronal synapses or microglia. Glucose transported to astrocytes by GLUT1 is metabolized to lactate serving to neurons as energy source. Proinflammatory cytokine interleukin (IL)-1β upregulates GLUT1 in endothelial cells and astrocytes, whereas it induces neuronal death in neuronal cell culture. GLUT2 is present in hypothalamic neurons and serves as a glucose sensor in regulation of food intake. In neurons of the hippocampus, GLUT2 is supposed to regulate synaptic activity and neurotransmitter release. GLUT3 is the most abundant glucose transporter in the brain having five times higher transport capacity than GLUT1. It is present in neuropil, mostly in axons and dendrites. Its density and distribution correlate well with the local cerebral glucose demands. GLUT5 is predominantly fructose transporter. In brain, GLUT5 is the only hexose transporter in microglia, whose regulation is not yet clear. It is not present in neurons. GLUT4 and GLUT8 are insulin-regulated glucose transporters in neuronal cell bodies in the cortex and cerebellum, but mainly in the hippocampus and amygdala, where they maintain hippocampus-dependent cognitive functions. Insulin translocates GLUT4 from cytosol to plasma membrane to transport glucose into cells, and GLUT8 from cytosol to rough endoplasmic reticulum to recover redundant glucose to cytosol after protein glycosylation. In autoimmune diseases, the enhanced glucose uptake was found in inflamed peripheral tissue, mainly due to proliferating fibroblasts and activated macrophages. In our experimental model of rheumatoid arthritis (adjuvant arthritis), enhanced 2-deoxy-2[F-18]fluoro-D-glucose was found in the hippocampus and amygdala two days after the induction of the disease which, similarly as in the peripheral joints, can be ascribed to the activated macrophages. The knowledge on the glucose transport and the role of glucose transporters in the brain during systemic autoimmune inflammation is still incomplete and needs further investigations.

  17. WRKY6 Transcription Factor Restricts Arsenate Uptake and Transposon Activation in Arabidopsis[W

    PubMed Central

    Castrillo, Gabriel; Sánchez-Bermejo, Eduardo; de Lorenzo, Laura; Crevillén, Pedro; Fraile-Escanciano, Ana; TC, Mohan; Mouriz, Alfonso; Catarecha, Pablo; Sobrino-Plata, Juan; Olsson, Sanna; Leo del Puerto, Yolanda; Mateos, Isabel; Rojo, Enrique; Hernández, Luis E.; Jarillo, Jose A.; Piñeiro, Manuel; Paz-Ares, Javier; Leyva, Antonio

    2013-01-01

    Stress constantly challenges plant adaptation to the environment. Of all stress types, arsenic was a major threat during the early evolution of plants. The most prevalent chemical form of arsenic is arsenate, whose similarity to phosphate renders it easily incorporated into cells via the phosphate transporters. Here, we found that arsenate stress provokes a notable transposon burst in plants, in coordination with arsenate/phosphate transporter repression, which immediately restricts arsenate uptake. This repression was accompanied by delocalization of the phosphate transporter from the plasma membrane. When arsenate was removed, the system rapidly restored transcriptional expression and membrane localization of the transporter. We identify WRKY6 as an arsenate-responsive transcription factor that mediates arsenate/phosphate transporter gene expression and restricts arsenate-induced transposon activation. Plants therefore have a dual WRKY-dependent signaling mechanism that modulates arsenate uptake and transposon expression, providing a coordinated strategy for arsenate tolerance and transposon gene silencing. PMID:23922208

  18. System data communication structures for active-control transport aircraft, volume 2

    NASA Technical Reports Server (NTRS)

    Hopkins, A. L.; Martin, J. H.; Brock, L. D.; Jansson, D. G.; Serben, S.; Smith, T. B.; Hanley, L. D.

    1981-01-01

    The application of communication structures to advanced transport aircraft are addressed. First, a set of avionic functional requirements is established, and a baseline set of avionics equipment is defined that will meet the requirements. Three alternative configurations for this equipment are then identified that represent the evolution toward more dispersed systems. Candidate communication structures are proposed for each system configuration, and these are compared using trade off analyses; these analyses emphasize reliability but also address complexity. Multiplex buses are recognized as the likely near term choice with mesh networks being desirable for advanced, highly dispersed systems.

  19. Simulated-airline-service flight tests of laminar-flow control with perforated-surface suction system

    NASA Technical Reports Server (NTRS)

    Maddalon, Dal V.; Braslow, Albert L.

    1990-01-01

    The effectiveness and practicality of candidate leading edge systems for suction laminar flow control transport airplanes were investigated in a flight test program utilizing a modified JetStar airplane. The leading edge region imposes the most severe conditions on systems required for any type of laminar flow control. Tests of the leading edge systems, therefore, provided definitive results as to the feasibility of active laminar flow control on airplanes. The test airplane was operated under commercial transport operating procedures from various commercial airports and at various seasons of the year.

  20. Built Environment and Active Transport to School (BEATS) Study: protocol for a cross-sectional study

    PubMed Central

    Mandic, Sandra; Williams, John; Moore, Antoni; Hopkins, Debbie; Flaherty, Charlotte; Wilson, Gordon; García Bengoechea, Enrique; Spence, John C

    2016-01-01

    Introduction Active transport to school (ATS) is a convenient way to increase physical activity and undertake an environmentally sustainable travel practice. The Built Environment and Active Transport to School (BEATS) Study examines ATS in adolescents in Dunedin, New Zealand, using ecological models for active transport that account for individual, social, environmental and policy factors. The study objectives are to: (1) understand the reasons behind adolescents and their parents' choice of transport mode to school; (2) examine the interaction between the transport choices, built environment, physical activity and weight status in adolescents; and (3) identify policies that promote or hinder ATS in adolescents. Methods and analysis The study will use a mixed-method approach incorporating both quantitative (surveys, anthropometry, accelerometers, Geographic Information System (GIS) analysis, mapping) and qualitative methods (focus groups, interviews) to gather data from students, parents, teachers and school principals. The core data will include accelerometer-measured physical activity, anthropometry, GIS measures of the built environment and the use of maps indicating route to school (students)/work (parents) and perceived safe/unsafe areas along the route. To provide comprehensive data for understanding how to change the infrastructure to support ATS, the study will also examine complementary variables such as individual, family and social factors, including student and parental perceptions of walking and cycling to school, parental perceptions of different modes of transport to school, perceptions of the neighbourhood environment, route to school (students)/work (parents), perceptions of driving, use of information communication technology, reasons for choosing a particular school and student and parental physical activity habits, screen time and weight status. The study has achieved a 100% school recruitment rate (12 secondary schools). Ethics and dissemination The study has been approved by the University of Otago Ethics Committee. The results will be actively disseminated through reports and presentations to stakeholders, symposiums and scientific publications. PMID:27221127

  1. Sucrose-mediated transcriptional regulation of sucrose symporter activity in the phloem.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Matt Vaughn Greg Harrington Daniel R Bush

    2002-08-06

    This project was based on our discovery that sucrose acts as a signaling molecule that regulates the activity of a proton-sucrose symporter in sugar beet leaf tissue. A major objective here was determining how sucrose transporter activity is being regulated. When sucrose accumulates in the phloem sucrose transport activity drops dramatically. Western blots of plasma membrane proteins isolated from sucrose treated leaves showed that the loss of sucrose transport activity was proportional to a decline in symporter abundance, demonstrating that sucrose transport is regulated by changes in the amount of BvSUT1 protein. BvSUT1 transcript levels decreased in parallel with themore » loss of sucrose transport activity. Nuclear run-on experiments demonstrated that BvSUT1 gene transcription was repressed significantly in nuclei from leaves fed 100 mM exogenous sucrose, showing that sucrose-dependent modulation of BvSUT1 mRNA levels is mediated by changes in transcription. To identify which secondary messenger systems might be involved in regulating symporter activity, we used a variety of pharmacological agents to probe for a role of calcium or protein phosphorylation in sucrose signaling. In a detailed analysis, only okadaic acid altered sucrose transport activity. These results suggest a protein phosphatase is involved. We hypothesized that protein kinase inhibitors would have a neutral affect or increase symporter transcription. Transpirational feeding of the protein kinase inhibitor staurosporine had no impact on sucrose transport while calphostin C, an inhibitor of protein kinase C, caused a 60% increase. These data provided good evidence that protein phosphorylation plays a central role in regulating sucrose symporter expression and sucrose transport activity. To determine whether protein phosphorylation is involved in sucrose regulation of proton-sucrose symporter activity, we pre-fed leaves with staurosporine for 4 h and then fed the treated leaves water or 100 mM sucrose for an additional 20 h. Sucrose transport activity was higher than the water control in both staurosporine/water- and staurosporine/sucrose-fed leaves. In contrast, sucrose transport activity was only 40% of the water control in sucrose-fed leaves. Taken together, these results showed that a phosphorylation-dependent signal transduction pathway is involved in sucrose-mediated regulation of BvSUT1 gene expression, sucrose transport activity, and ultimately phloem loading. Publications originating from this work: Vaughn MW, GN. Harrington, and DR Bush 2002. Sucrose-mediated transcriptional regulation of sucrose symporter activity in the phloem. Proc. Natl. Acad. Sci. USA 99:10876-10880 Ransom-Hodgkins W, MW Vaughn, and DR Bush 2003. Protein phosphorylation mediates a key step in sucrose-regulation of the expression and transport activity of a beet proton-sucrose symporter. Planta 217:483-489 Harrington GN and Bush DR 2003. The bifunctional role of hexokinase in metabolism and glucose signaling. Plant Cell 15: 2493-2496« less

  2. Vibrio Iron Transport: Evolutionary Adaptation to Life in Multiple Environments

    PubMed Central

    Mey, Alexandra R.; Wyckoff, Elizabeth E.

    2015-01-01

    SUMMARY Iron is an essential element for Vibrio spp., but the acquisition of iron is complicated by its tendency to form insoluble ferric complexes in nature and its association with high-affinity iron-binding proteins in the host. Vibrios occupy a variety of different niches, and each of these niches presents particular challenges for acquiring sufficient iron. Vibrio species have evolved a wide array of iron transport systems that allow the bacteria to compete for this essential element in each of its habitats. These systems include the secretion and uptake of high-affinity iron-binding compounds (siderophores) as well as transport systems for iron bound to host complexes. Transporters for ferric and ferrous iron not complexed to siderophores are also common to Vibrio species. Some of the genes encoding these systems show evidence of horizontal transmission, and the ability to acquire and incorporate additional iron transport systems may have allowed Vibrio species to more rapidly adapt to new environmental niches. While too little iron prevents growth of the bacteria, too much can be lethal. The appropriate balance is maintained in vibrios through complex regulatory networks involving transcriptional repressors and activators and small RNAs (sRNAs) that act posttranscriptionally. Examination of the number and variety of iron transport systems found in Vibrio spp. offers insights into how this group of bacteria has adapted to such a wide range of habitats. PMID:26658001

  3. Light-activated amino acid transport in Halobacterium halobium envelope vesicles

    NASA Technical Reports Server (NTRS)

    Macdonald, R. E.; Lanyi, J. K.

    1977-01-01

    Vesicles prepared from Halobacterium halobium cell envelopes accumulate amino acids in response to light-induced electrical and chemical gradients. Nineteen of 20 commonly occurring amino acids have been shown to be actively accumulated by these vesicles in response to illumination or in response to an artificially created Na+ gradient. On the basis of shared common carriers the transport systems can be divided into eight classes, each responsible for the transport of one or several amino acids: arginine, lysine, histidine; asparagine, glutamine; alanine, glycine, threonine, serine; leucine, valine, isoleucine, methionine; phenylalanine, tyrosine, tryptophan; aspartate; glutamate; proline. Available evidence suggests that these carriers are symmetrical in that amino acids can be transported equally well in both directions across the vesicle membranes. A tentative working model to account for these observations is presented.

  4. Accelerated development and flight evaluation of active controls concepts for subsonic transport aircraft. Volume 2: AFT C.G. simulation and analysis

    NASA Technical Reports Server (NTRS)

    Urie, D. M.

    1979-01-01

    Relaxed static stability and stability augmentation with active controls were investigated for subsonic transport aircraft. Analytical and simulator evaluations were done using a contemporary wide body transport as a baseline. Criteria for augmentation system performance and unaugmented flying qualities were evaluated. Augmentation control laws were defined based on selected frequency response and time history criteria. Flying qualities evaluations were conducted by pilots using a moving base simulator with a transport cab. Static margin and air turbulence intensity were varied in test with and without augmentation. Suitability of a simple pitch control law was verified at neutral static margin in cruise and landing flight tasks. Neutral stability was found to be marginally acceptable in heavy turbulence in both cruise and landing conditions.

  5. 14 CFR 27.672 - Stability augmentation, automatic, and power-operated systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.672 Stability augmentation, automatic, and power-operated systems. If the... unsafe condition if the pilot is unaware of the failure. Warning systems must not activate the control...

  6. Placental Glucose and Amino Acid Transport in Calorie-Restricted Wild-Type and Glut3 Null Heterozygous Mice

    PubMed Central

    Ganguly, Amit; Collis, Laura

    2012-01-01

    Calorie restriction (CR) decreased placenta and fetal weights in wild-type (wt) and glucose transporter (Glut) 3 heterozygous null (glut3+/−) mice. Because placental nutrient transport is a primary energy determinant of placentofetal growth, we examined key transport systems. Maternal CR reduced intra- and transplacental glucose and leucine transport but enhanced system A amino acid transport in wt mice. These transport perturbations were accompanied by reduced placental Glut3 and leucine amino acid transporter (LAT) family member 2, no change in Glut1 and LAT family member 1, but increased sodium coupled neutral amino acid transporter (SNAT) and SNAT2 expression. We also noted decreased total and active phosphorylated forms of mammalian target of rapamycin, which is the intracellular nutrient sensor, the downstream total P70S6 kinase, and pS6 ribosomal protein with no change in total and phosphorylated 4E-binding protein 1. To determine the role of placental Glut3 in mediating CR-induced placental transport changes, we next investigated the effect of gestational CR in glut3+/− mice. In glut3+/− mice, a key role of placental Glut3 in mediating transplacental and intraplacental glucose transport was established. In addition, reduced Glut3 results in a compensatory increase of leucine and system A transplacental transport. On the other hand, diminished Glut3-mediated intraplacental glucose transport reduced leucine transport and mammalian target of rapamycin and preserved LAT and enhancing SNAT. CR in glut3+/− mice further reduced transplacental glucose transport and enhanced system A amino acid transport, although the increased leucine transport was lost. In addition, increased Glut3 was seen and preserved Glut1, LAT, and SNAT. These placental changes collectively protect survival of wt and glut3+/− fetuses against maternal CR-imposed reduction of macromolecular nutrients. PMID:22700768

  7. The absence of intrarenal ACE protects against hypertension

    PubMed Central

    Gonzalez-Villalobos, Romer A.; Janjoulia, Tea; Fletcher, Nicholas K.; Giani, Jorge F.; Nguyen, Mien T.X.; Riquier-Brison, Anne D.; Seth, Dale M.; Fuchs, Sebastien; Eladari, Dominique; Picard, Nicolas; Bachmann, Sebastian; Delpire, Eric; Peti-Peterdi, Janos; Navar, L. Gabriel; Bernstein, Kenneth E.; McDonough, Alicia A.

    2013-01-01

    Activation of the intrarenal renin-angiotensin system (RAS) can elicit hypertension independently from the systemic RAS. However, the precise mechanisms by which intrarenal Ang II increases blood pressure have never been identified. To this end, we studied the responses of mice specifically lacking kidney angiotensin-converting enzyme (ACE) to experimental hypertension. Here, we show that the absence of kidney ACE substantially blunts the hypertension induced by Ang II infusion (a model of high serum Ang II) or by nitric oxide synthesis inhibition (a model of low serum Ang II). Moreover, the renal responses to high serum Ang II observed in wild-type mice, including intrarenal Ang II accumulation, sodium and water retention, and activation of ion transporters in the loop of Henle (NKCC2) and distal nephron (NCC, ENaC, and pendrin) as well as the transporter activating kinases SPAK and OSR1, were effectively prevented in mice that lack kidney ACE. These findings demonstrate that ACE metabolism plays a fundamental role in the responses of the kidney to hypertensive stimuli. In particular, renal ACE activity is required to increase local Ang II, to stimulate sodium transport in loop of Henle and the distal nephron, and to induce hypertension. PMID:23619363

  8. Space Station technology testbed: 2010 deep space transport

    NASA Technical Reports Server (NTRS)

    Holt, Alan C.

    1993-01-01

    A space station in a crew-tended or permanently crewed configuration will provide major R&D opportunities for innovative, technology and materials development and advanced space systems testing. A space station should be designed with the basic infrastructure elements required to grow into a major systems technology testbed. This space-based technology testbed can and should be used to support the development of technologies required to expand our utilization of near-Earth space, the Moon and the Earth-to-Jupiter region of the Solar System. Space station support of advanced technology and materials development will result in new techniques for high priority scientific research and the knowledge and R&D base needed for the development of major, new commercial product thrusts. To illustrate the technology testbed potential of a space station and to point the way to a bold, innovative approach to advanced space systems' development, a hypothetical deep space transport development and test plan is described. Key deep space transport R&D activities are described would lead to the readiness certification of an advanced, reusable interplanetary transport capable of supporting eight crewmembers or more. With the support of a focused and highly motivated, multi-agency ground R&D program, a deep space transport of this type could be assembled and tested by 2010. Key R&D activities on a space station would include: (1) experimental research investigating the microgravity assisted, restructuring of micro-engineered, materials (to develop and verify the in-space and in-situ 'tuning' of materials for use in debris and radiation shielding and other protective systems), (2) exposure of microengineered materials to the space environment for passive and operational performance tests (to develop in-situ maintenance and repair techniques and to support the development, enhancement, and implementation of protective systems, data and bio-processing systems, and virtual reality and telepresence/kinetic processes), (3) subsystem tests of advanced nuclear power, nuclear propulsion and communication systems (using boom extensions, remote station-keeping platforms and mobile EVA crew and robots), and (4) logistics support (crew and equipment) and command and control of deep space transport assembly, maintenance, and refueling (using a station-keeping platform).

  9. 17 CFR 39.34 - System safeguards for systemically important derivatives clearing organizations and subpart C...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... rely on the same critical transportation, telecommunications, power, water, or other critical infrastructure components the entity normally relies upon for such activities; (2) Personnel, who live and work...

  10. Pennsylvania Turnpike Commission's advanced traveler information system (ATIS) phase III project

    DOT National Transportation Integrated Search

    2006-02-14

    In October 1998, the Pennsylvania Turnpike Commission (Commission) submitted a Partnership Agreement to the Federal Highway Administration (FHWA) for specific Intelligent Transportation Systems (ITS) activities, and to maximize the involvement of the...

  11. Protein kinase C activation decreases cell surface expression of the GLT-1 subtype of glutamate transporter. Requirement of a carboxyl-terminal domain and partial dependence on serine 486.

    PubMed

    Kalandadze, Avtandil; Wu, Ying; Robinson, Michael B

    2002-11-29

    Na(+)-dependent glutamate transporters are required for the clearance of extracellular glutamate and influence both physiological and pathological effects of this excitatory amino acid. In the present study, the effects of a protein kinase C (PKC) activator on the cell surface expression and activity of the GLT-1 subtype of glutamate transporter were examined in two model systems, primary co-cultures of neurons and astrocytes that endogenously express GLT-1 and C6 glioma cells transfected with GLT-1. In both systems, activation of PKC with phorbol ester caused a decrease in GLT-1 cell surface expression. This effect is opposite to the one observed for the EAAC1 subtype of glutamate transporter (Davis, K. E., Straff, D. J., Weinstein, E. A., Bannerman, P. G., Correale, D. M., Rothstein, J. D., and Robinson, M. B. (1998) J. Neurosci. 18, 2475-2485). Several recombinant chimeric proteins between GLT-1 and EAAC1 transporter subtypes were generated to identify domains required for the subtype-specific redistribution of GLT-1. We identified a carboxyl-terminal domain consisting of 43 amino acids (amino acids 475-517) that is required for PKC-induced GLT-1 redistribution. Mutation of a non-conserved serine residue at position 486 partially attenuated but did not completely abolish the PKC-dependent redistribution of GLT-1. Although we observed a phorbol ester-dependent incorporation of (32)P into immunoprecipitable GLT-1, mutation of serine 486 did not reduce this signal. We also found that chimeras containing the first 446 amino acids of GLT-1 were not functional unless amino acids 475-517 of GLT-1 were also present. These non-functional transporters were not as efficiently expressed on the cell surface and migrated to a smaller molecular weight, suggesting that a subtype-specific interaction is required for the formation of functional transporters. These studies demonstrate a novel effect of PKC on GLT-1 activity and define a unique carboxyl-terminal domain as an important determinant in cellular localization and regulation of GLT-1.

  12. Abscisic acid accumulation modulates auxin transport in the root tip to enhance proton secretion for maintaining root growth under moderate water stress.

    PubMed

    Xu, Weifeng; Jia, Liguo; Shi, Weiming; Liang, Jiansheng; Zhou, Feng; Li, Qianfeng; Zhang, Jianhua

    2013-01-01

    Maintenance of root growth is essential for plant adaptation to soil drying. Here, we tested the hypothesis that auxin transport is involved in mediating ABA's modulation by activating proton secretion in the root tip to maintain root growth under moderate water stress. Rice and Arabidopsis plants were raised under a hydroponic system and subjected to moderate water stress (-0.47 MPa) with polyethylene glycol (PEG). ABA accumulation, auxin transport and plasma membrane H(+)-ATPase activity at the root tip were monitored in addition to the primary root elongation and root hair density. We found that moderate water stress increases ABA accumulation and auxin transport in the root apex. Additionally, ABA modulation is involved in the regulation of auxin transport in the root tip. The transported auxin activates the plasma membrane H(+)-ATPase to release more protons along the root tip in its adaption to moderate water stress. The proton secretion in the root tip is essential in maintaining or promoting primary root elongation and root hair development under moderate water stress. These results suggest that ABA accumulation modulates auxin transport in the root tip, which enhances proton secretion for maintaining root growth under moderate water stress. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  13. Auxin polar transport in arabidopsis under simulated microgravity conditions - relevance to growth and development

    NASA Astrophysics Data System (ADS)

    Miyamoto, K.; Oka, M.; Yamamoto, R.; Masuda, Y.; Hoson, T.; Kamisaka, S.; Ueda, J.

    1999-01-01

    Activity of auxin polar transport in inflorescence axes of Arabidopsis thaliana grown under simulated microgravity conditions was studied in relation to the growth and development. Seeds were germinated and allowed to grow on an agar medium in test tubes on a horizontal clinostat. Horizontal clinostat rotation substantially reduced the growth of inflorescence axes and the productivity of seeds of Arabidopsis thaliana (ecotypes Landsberg erecta and Columbia), although it little affected seed germination, development of rosette leaves and flowering. The activity of auxin polar transport in inflorescence axes decreased when Arabidopsis plants were grown on a horizontal clinostat from germination stage, being ca. 60% of 1 g control. On the other hand, the auxin polar transport in inflorescence axes of Arabidopsis grown in 1 g conditions was not affected when the segments were exposed to various gravistimuli, including 3-dimensional clinorotation, during transport experiments. Pin-formed mutant of Arabidopsis, having a unique structure of the inflorescence axis with no flower and extremely low levels of the activity of auxin polar transport in inflorescence axes and endogenous auxin, did not continue its vegetative growth under clinostat rotation. These facts suggest that the development of the system of auxin polar transport in Arabidopsis is affected by microgravity, resulting in the inhibition of growth and development, especially during reproductive growth.

  14. E&P forum land transport safety management guidelines

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Barber, S.; Carouso, M.; Covil, M.

    1996-11-01

    Against a general background of falling lost time injuries the member of serious incidents and fatalities in the upstream E&P industry involving motor vehicles employed in land transport remains stubbornly high. In consequence the E&P Forum has prepared guidelines to provide the E&P industry with clear guidance and a shared aim in minimizing vehicle incidents and their costs. Logistics and land transport are multifunctional activities involving personnel throughout the E&P industry. All those involved in land transport share a joint commitment to amazing land transport risks in their operation and to preventing incidents and fatalities as stated in their HSEmore » policies. Historically management`s focus has been on those activities which have a higher perceived risk. This attention has resulted in significant reductions in the number of accidents in these areas. The management of land transport safety requires the same approach and the same proactive emphasis as the management of other HSE risks within the business activity. Companies should have in place a management system for land transport operations based on a full and careful appraisal of the risks, followed by a clear management strategy to minimis and control those risks to a level as low as reasonably practicable.« less

  15. Early Decline in Glucose Transport and Metabolism Precedes Shift to Ketogenic System in Female Aging and Alzheimer's Mouse Brain: Implication for Bioenergetic Intervention

    PubMed Central

    Ding, Fan; Yao, Jia; Rettberg, Jamaica R.; Chen, Shuhua; Brinton, Roberta Diaz

    2013-01-01

    We previously demonstrated that mitochondrial bioenergetic deficits in the female brain accompanied reproductive senescence and was accompanied by a shift from an aerobic glycolytic to a ketogenic phenotype. Herein, we investigated the relationship between systems of fuel supply, transport and mitochondrial metabolic enzyme expression/activity during aging (3–15 months) in the hippocampus of nontransgenic (nonTg) background and 3xTgAD female mice. Results indicate that during female brain aging, both nonTg and 3xTgAD brains undergo significant decline in glucose transport, as detected by FDG-microPET, between 6–9 months of age just prior to the transition into reproductive senescence. The deficit in brain metabolism was sustained thereafter. Decline in glucose transport coincided with significant decline in neuronal glucose transporter expression and hexokinase activity with a concomitant rise in phosphorylated/inactivated pyruvate dehydrogenase. Lactate utilization declined in parallel to the decline in glucose transport suggesting lactate did not serve as an alternative fuel. An adaptive response in the nonTg hippocampus was a shift to transport and utilization of ketone bodies as an alternative fuel. In the 3xTgAD brain, utilization of ketone bodies as an alternative fuel was evident at the earliest age investigated and declined thereafter. The 3xTgAD adaptive response was to substantially increase monocarboxylate transporters in neurons while decreasing their expression at the BBB and in astrocytes. Collectively, these data indicate that the earliest change in the metabolic system of the aging female brain is the decline in neuronal glucose transport and metabolism followed by decline in mitochondrial function. The adaptive shift to the ketogenic system as an alternative fuel coincided with decline in mitochondrial function. Translationally, these data provide insights into the earliest events in bioenergetic aging of the female brain and provide potential targets for preventing shifts to less efficient bioenergetic fuels and transition to the ketogenic phenotype of the Alzheimer's brain. PMID:24244584

  16. A cislunar transportation system fuelled by lunar resources

    NASA Astrophysics Data System (ADS)

    Sowers, G. F.

    2016-11-01

    A transportation system for a self sustaining economy in cislunar space is discussed. The system is based on liquid oxygen (LO2), liquid hydrogen (LH2) propulsion whose fuels are derived from ice mined at the polar regions of the Moon. The elements of the transportation system consist of the Advanced Cryogenic Evolved Stage (ACES) and the XEUS lander, both being developed by United Launch Alliance (ULA). The main propulsion elements and structures are common between ACES and XEUS. Both stages are fully reusable with refueling of their LO2/LH2 propellants. Utilization of lunar sourced propellants has the potential to dramatically lower the cost of transportation within the cislunar environs. These lower costs dramatically lower the barriers to entry of a number of promising cislunar based activities including space solar power. One early application of the architecture is providing lunar sourced propellant to refuel ACES for traditional spacecraft deployment missions. The business case for this application provides an economic framework for a potential lunar water mining operation.

  17. Final Report: Mass Production Cost Estimation of Direct H2 PEM Fuel Cell Systems for Transportation Applications (2012-2016)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    James, Brian David; Huya-Kouadio, Jennie Moton; Houchins, Cassidy

    This report summarizes project activities for Strategic Analysis, Inc. (SA) Contract Number DE-EE0005236 to the U.S. Department of Energy titled “Transportation Fuel Cell System Cost Assessment”. The project defined and projected the mass production costs of direct hydrogen Proton Exchange Membrane fuel cell power systems for light-duty vehicles (automobiles) and 40-foot transit buses. In each year of the five-year contract, the fuel cell power system designs and cost projections were updated to reflect technology advances. System schematics, design assumptions, manufacturing assumptions, and cost results are presented.

  18. Transport processes of the legume symbiosome membrane

    PubMed Central

    Clarke, Victoria C.; Loughlin, Patrick C.; Day, David A.; Smith, Penelope M. C.

    2014-01-01

    The symbiosome membrane (SM) is a physical barrier between the host plant and nitrogen-fixing bacteria in the legume:rhizobia symbiosis, and represents a regulated interface for the movement of solutes between the symbionts that is under plant control. The primary nutrient exchange across the SM is the transport of a carbon energy source from plant to bacteroid in exchange for fixed nitrogen. At a biochemical level two channels have been implicated in movement of fixed nitrogen across the SM and a uniporter that transports monovalent dicarboxylate ions has been characterized that would transport fixed carbon. The aquaporin NOD26 may provide a channel for ammonia, but the genes encoding the other transporters have not been identified. Transport of several other solutes, including calcium and potassium, have been demonstrated in isolated symbiosomes, and genes encoding transport systems for the movement of iron, nitrate, sulfate, and zinc in nodules have been identified. However, definitively matching transport activities with these genes has proved difficult and many further transport processes are expected on the SM to facilitate the movement of nutrients between the symbionts. Recently, work detailing the SM proteome in soybean has been completed, contributing significantly to the database of known SM proteins. This represents a valuable resource for the identification of transporter protein candidates, some of which may correspond to transport processes previously described, or to novel transport systems in the symbiosis. Putative transporters identified from the proteome include homologs of transporters of sulfate, calcium, peptides, and various metal ions. Here we review current knowledge of transport processes of the SM and discuss the requirements for additional transport routes of other nutrients exchanged in the symbiosis, with a focus on transport systems identified through the soybean SM proteome. PMID:25566274

  19. Steps for Action: Getting Intelligent Transportation Systems Ready for the Year 2000. Partners for ITS Y2K.

    DOT National Transportation Integrated Search

    1999-01-01

    The purpose of this brochure is to serve as an organizing tool that will help you map out your Y2K problem-solving activities between now and January 1, 2000. During that period, the U.S. Department of Transportation will communicate the importance o...

  20. Space transfer concepts and analyses for exploration missions, phase 4

    NASA Technical Reports Server (NTRS)

    Woodcock, Gordon R.

    1993-01-01

    Earlier studies carried out under this contract covered a wide range of lunar and Mars transportation options, and lunar rove concepts and technology needs. The current report discusses the activities conducted under Technical Directives 16 and 17. Mars transportation was addressed as well as a review and update of architectures and propulsion systems.

  1. 76 FR 53045 - Prevailing Rate Systems; Abolishment of Monmouth, NJ, as a Nonappropriated Fund Federal Wage...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-25

    ... contains regulatory documents #0;having general applicability and legal effect, most of which are keyed #0... facilities activity in each county; Transportation facilities and commuting patterns; and Similarities of the... employees. The transportation facilities and commuting patterns criteria do not favor one wage area more...

  2. Bovine neuronal vesicular glutamate transporter activity is inhibited by ergovaline and other ergopeptines

    USDA-ARS?s Scientific Manuscript database

    L-Glutamate (Glu) is the major excitatory neurotransmitter responsible for neurotransmission in the vertebrate central nervous system, including the gastrointestinal tract (GIT) of cattle. Vesicular Glu transporters VGLUT1 and VGLUT2 concentrate (50 mM) Glu (Km = 1 to 4 mM) into synaptic vesicles (S...

  3. Caveolin-1-mediated internalization of the vitamin C transporter SVCT2 in microglia triggers an inflammatory phenotype.

    PubMed

    Portugal, Camila C; Socodato, Renato; Canedo, Teresa; Silva, Cátia M; Martins, Tânia; Coreixas, Vivian S M; Loiola, Erick C; Gess, Burkhard; Röhr, Dominik; Santiago, Ana R; Young, Peter; Minshall, Richard D; Paes-de-Carvalho, Roberto; Ambrósio, António F; Relvas, João B

    2017-03-28

    Vitamin C is essential for the development and function of the central nervous system (CNS). The plasma membrane sodium-vitamin C cotransporter 2 (SVCT2) is the primary mediator of vitamin C uptake in neurons. SVCT2 specifically transports ascorbate, the reduced form of vitamin C, which acts as a reducing agent. We demonstrated that ascorbate uptake through SVCT2 was critical for the homeostasis of microglia, the resident myeloid cells of the CNS that are essential for proper functioning of the nervous tissue. We found that depletion of SVCT2 from the plasma membrane triggered a proinflammatory phenotype in microglia and resulted in microglia activation. Src-mediated phosphorylation of caveolin-1 on Tyr 14 in microglia induced the internalization of SVCT2. Ascorbate treatment, SVCT2 overexpression, or blocking SVCT2 internalization prevented the activation of microglia. Overall, our work demonstrates the importance of the ascorbate transport system for microglial homeostasis and hints that dysregulation of ascorbate transport might play a role in neurological disorders. Copyright © 2017, American Association for the Advancement of Science.

  4. Space transportation node - The Atrium Facility

    NASA Technical Reports Server (NTRS)

    Kennedy, Kriss J.

    1990-01-01

    A conceptual design for a space transportation node is presented with a view to the fulfilment of assembly platform support requirements associated with a lunar transportation system. This 'Atrium Facility', which will support lunar base activities before, during, and after the lunar base buildup phase, encompasses a central assembly area surrounded by hangars and workstation platforms; six permanent crewmembers will be supported, as well as four to six transient lunar and Space Shuttle crewmembers. The Atrium Facility dry mass of nearly 320,000 kg excludes cryogenic propellant stowage and the traslunar vehicle envisioned for transportation.

  5. Active Solute Transport across Frog Skin and Epithelial Cell Systems According to the Association-Induction Hypothesis,

    DTIC Science & Technology

    1980-01-01

    indicated in insect Malpighian tubules, insect midgut , choroid plexus and gastric mucosa. 9.2.5 Conciliation of the Conflict Between Models of "Homocellular...SeApeinaebility is therefore under close I Ling (P;. 14) control by hormones or drugs that react with receptor sites on these protelns and so...bears remembering that in active transport across bifacial cells the key cation is not always No% Thus in MalPighian tubules of insects the key Lon

  6. Sirtuin Activation: A Role for Plasma Membrane in the Cell Growth Puzzle

    PubMed Central

    2013-01-01

    For more than 20 years, the observation that impermeable oxidants can stimulate cell growth has not been satisfactorily explained. The discovery of sirtuins provides a logical answer to the puzzle. The NADH-dependent transplasma membrane electron transport system, which is stimulated by growth factors and interventions such as calorie restriction, can transfer electrons to external acceptors and protect against stress-induced apoptosis. We hypothesize that the activation of plasma membrane electron transport contributes to the cytosolic NAD+ pool required for sirtuin to activate transcription factors necessary for cell growth and survival. PMID:23033342

  7. Concepts for the material development of phosphorescent organic materials processable from solution and their application in OLEDs

    NASA Astrophysics Data System (ADS)

    Janietz, S.; Krueger, H.; Thesen, M.; Salert, B.; Wedel, A.

    2014-10-01

    One example of organic electronics is the application of polymer based light emitting devices (PLEDs). PLEDs are very attractive for large area and fine-pixel displays, lighting and signage. The polymers are more amenable to solution processing by printing techniques which are favourable for low cost production in large areas. With phosphorescent emitters like Ir-complexes higher quantum efficiencies were obtained than with fluorescent systems, especially if multilayer stack systems with separated charge transport and emitting layers were applied in the case of small molecules. Polymers exhibit the ability to integrate all the active components like the hole-, electron-transport and phosphorescent molecules in only one layer. Here, the active components of a phosphorescent system - triplet emitter, hole- and electron transport molecules - can be linked as a side group to a polystyrene main chain. By varying the molecular structures of the side groups as well as the composition of the side chains with respect to the triplet emitter, hole- and electron transport structure, and by blending with suitable glass-forming, so-called small molecules, brightness, efficiency and lifetime of the produced OLEDs can be optimized. By choosing the triplet emitter, such as iridium complexes, different emission colors can be specially set. Different substituted triazine molecules were introduced as side chain into a polystyrene backbone and applied as electron transport material in PLED blend systems. The influence of alkyl chain lengths of the performance will be discussed. For an optimized blend system with a green emitting phosphorescent Ir-complex efficiencies of 60 cd/A and an lifetime improvement of 66.000 h @ 1000 cd/m2 were achieved.

  8. Cytoskeletal Network Morphology Regulates Intracellular Transport Dynamics

    PubMed Central

    Ando, David; Korabel, Nickolay; Huang, Kerwyn Casey; Gopinathan, Ajay

    2015-01-01

    Intracellular transport is essential for maintaining proper cellular function in most eukaryotic cells, with perturbations in active transport resulting in several types of disease. Efficient delivery of critical cargos to specific locations is accomplished through a combination of passive diffusion and active transport by molecular motors that ballistically move along a network of cytoskeletal filaments. Although motor-based transport is known to be necessary to overcome cytoplasmic crowding and the limited range of diffusion within reasonable timescales, the topological features of the cytoskeletal network that regulate transport efficiency and robustness have not been established. Using a continuum diffusion model, we observed that the time required for cellular transport was minimized when the network was localized near the nucleus. In simulations that explicitly incorporated network spatial architectures, total filament mass was the primary driver of network transit times. However, filament traps that redirect cargo back to the nucleus caused large variations in network transport. Filament polarity was more important than filament orientation in reducing average transit times, and transport properties were optimized in networks with intermediate motor on and off rates. Our results provide important insights into the functional constraints on intracellular transport under which cells have evolved cytoskeletal structures, and have potential applications for enhancing reactions in biomimetic systems through rational transport network design. PMID:26488648

  9. Magnetic hard gap due to bound magnetic polarons in the localized regime.

    PubMed

    Rimal, Gaurab; Tang, Jinke

    2017-02-08

    We investigate the low temperature electron transport properties of manganese doped lead sulfide films. The system shows variable range hopping at low temperatures that crosses over into an activation regime at even lower temperatures. This crossover is destroyed by an applied magnetic field which suggests a magnetic origin of the hard gap, associated with bound magnetic polarons. Even though the gap forms around the superconducting transition temperature of lead, we do not find evidence of this being due to insulator-superconductor transition. Comparison with undoped PbS films, which do not show the activated transport behavior, suggests that bound magnetic polarons create the hard gap in the system that can be closed by magnetic fields.

  10. 49 CFR 236.1027 - PTC system exclusions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... distributed computer-based system that directly or indirectly controls the active movement of trains in a rail... 49 Transportation 4 2010-10-01 2010-10-01 false PTC system exclusions. 236.1027 Section 236.1027..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Positive Train Control...

  11. 49 CFR 236.1027 - PTC system exclusions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... distributed computer-based system that directly or indirectly controls the active movement of trains in a rail... 49 Transportation 4 2013-10-01 2013-10-01 false PTC system exclusions. 236.1027 Section 236.1027..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Positive Train Control...

  12. 49 CFR 236.1027 - PTC system exclusions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... distributed computer-based system that directly or indirectly controls the active movement of trains in a rail... 49 Transportation 4 2011-10-01 2011-10-01 false PTC system exclusions. 236.1027 Section 236.1027..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Positive Train Control...

  13. 49 CFR 236.1027 - PTC system exclusions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... distributed computer-based system that directly or indirectly controls the active movement of trains in a rail... 49 Transportation 4 2014-10-01 2014-10-01 false PTC system exclusions. 236.1027 Section 236.1027..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Positive Train Control...

  14. 49 CFR 236.1027 - PTC system exclusions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... distributed computer-based system that directly or indirectly controls the active movement of trains in a rail... 49 Transportation 4 2012-10-01 2012-10-01 false PTC system exclusions. 236.1027 Section 236.1027..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Positive Train Control...

  15. Pendular behavior of public transport networks

    NASA Astrophysics Data System (ADS)

    Izawa, Mirian M.; Oliveira, Fernando A.; Cajueiro, Daniel O.; Mello, Bernardo A.

    2017-07-01

    In this paper, we propose a methodology that bears close resemblance to the Fourier analysis of the first harmonic to study networks subjected to pendular behavior. In this context, pendular behavior is characterized by the phenomenon of people's dislocation from their homes to work in the morning and people's dislocation in the opposite direction in the afternoon. Pendular behavior is a relevant phenomenon that takes place in public transport networks because it may reduce the overall efficiency of the system as a result of the asymmetric utilization of the system in different directions. We apply this methodology to the bus transport system of Brasília, which is a city that has commercial and residential activities in distinct boroughs. We show that this methodology can be used to characterize the pendular behavior of this system, identifying the most critical nodes and times of the day when this system is in more severe demanded.

  16. The effects of the ride environment on intercity train passenger activities

    DOT National Transportation Integrated Search

    1979-01-01

    The ability to perform activities such as reading, writing, : talking, and sleeping has frequently been cited in the : ride quality literature as an important factor in passengers' : comfort and satisfaction with transportation systems. A field : stu...

  17. Operations and maintenance plan : Dallas Integrated Corridor Management (ICM) demonstration project.

    DOT National Transportation Integrated Search

    2014-01-01

    This Operations and Maintenance (O&M) Plan describes how the Integrated Corridor Management System (ICMS) will be used in daily transportation operations and maintenance activities. The Plan addresses the activities needed to effectively operate the ...

  18. 75 FR 53733 - Pipeline Safety: Information Collection Activities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-01

    ... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration [Docket No. PHMSA-2010-0246] Pipeline Safety: Information Collection Activities AGENCY: Pipeline and Hazardous... liquefied natural gas, hazardous liquid, and gas transmission pipeline systems operated by a company. The...

  19. Norepinephrine Transporter Heterozygous Knockout Mice Exhibit Altered Transport and Behavior

    PubMed Central

    Fentress, HM; Klar, R; Krueger, JK; Sabb, T; Redmon, SN; Wallace, NM; Shirey-Rice, JK; Hahn, MK

    2013-01-01

    The norepinephrine (NE) transporter (NET) regulates synaptic NE availability for noradrenergic signaling in the brain and sympathetic nervous system. Although genetic variation leading to a loss of NET expression has been implicated in psychiatric and cardiovascular disorders, complete NET deficiency has not been found in people, limiting the utility of NET knockout mice as a model for genetically-driven NET dysfunction. Here, we investigate NET expression in NET heterozygous knockout male mice (NET+/−), demonstrating that they display an ~50% reduction in NET protein levels. Surprisingly, these mice display no significant deficit in NET activity, assessed in hippocampal and cortical synaptosomes. We found that this compensation in NET activity was due to enhanced activity of surface-resident transporters, as opposed to surface recruitment of NET protein or compensation through other transport mechanisms, including serotonin, dopamine or organic cation transporters. We hypothesize that loss of NET protein in the NET+/− mouse establishes an activated state of existing, surface NET proteins. NET+/− mice exhibit increased anxiety in the open field and light-dark box and display deficits in reversal learning in the Morris Water Maze. These data suggest recovery of near basal activity in NET+/− mice appears to be insufficient to limit anxiety responses or support cognitive performance that might involve noradrenergic neurotransmission. The NET+/− mice represent a unique model to study the loss and resultant compensatory changes in NET that may be relevant to behavior and physiology in human NET deficiency disorders. PMID:24102798

  20. Associations of Perceived and Objectively Measured Neighborhood Environmental Attributes With Leisure-Time Sitting for Transport.

    PubMed

    Liao, Yung; Sugiyama, Takemi; Shibata, Ai; Ishii, Kaori; Inoue, Shigeru; Koohsari, Mohammad Javad; Owen, Neville; Oka, Koichiro

    2016-12-01

    This study examined associations of perceived and objectively measured neighborhood environmental attributes with leisure-time sitting for transport among middle-to-older aged Japanese adults. Data were collected using a postal survey of 998 adults aged 40 to 69 years. Generalized linear modeling with a gamma distribution and a log link was used to examine associations of perceived (International Physical Activity Questionnaire-Environmental module) and Geographic Information Systems (GIS)-derived built environment attributes with self-reported leisure-time sitting for transport. Mean leisure-time sitting time for transport was 20.4 min/day. After adjusting for potential confounders, perceived higher residential density, GIS-measured higher population density, better access to destinations, better access to public transport, longer sidewalk length, and higher street connectivity, were associated significantly with lower sitting time for transport. Residents living in neighborhoods with attributes previously found to be associated with more walking tended to spend less time sitting for transport during leisure-time. The health benefits of walkability-related attributes may accrue not only through increased physical activity, but also through less sedentary time.

  1. Inhibition of the ubiquitin-proteasome activity prevents glutamate transporter degradation and morphine tolerance.

    PubMed

    Yang, Liling; Wang, Shuxing; Lim, Grewo; Sung, Backil; Zeng, Qing; Mao, Jianren

    2008-12-01

    Glutamate transporters play a crucial role in physiological glutamate homeostasis and neurotoxicity. Recently, we have shown that downregulation of glutamate transporters after chronic morphine exposure contributed to the development of morphine tolerance. In the present study, we examined whether regulation of the glutamate transporter expression with the proposed proteasome inhibitor MG-132 would contribute to the development of tolerance to repeated intrathecal (twice daily x 7 days) morphine administration in rats. The results showed that MG-132 (5 nmol) given intrathecally blocked morphine-induced glutamate transporter downregulation and the decrease in glutamate uptake activity within the spinal cord dorsal horn. Co-administration of morphine (15 nmol) with MG-132 (vehicle=1<2.5<5=10 nmol) also dose-dependently prevented the development of morphine tolerance in rats. These findings suggest that prevention of spinal glutamate transporter downregulation may regulate the glutamatergic function that has been implicated in the development of morphine tolerance. The possible relationship between MG-132-mediated regulation of glutamate transporters, ubiquitin-proteasome system, and the cellular mechanisms of morphine tolerance is discussed in light of these findings.

  2. Changes in ion transport in inflammatory disease.

    PubMed

    Eisenhut, Michael

    2006-03-29

    Ion transport is essential for maintenance of transmembranous and transcellular electric potential, fluid transport and cellular volume. Disturbance of ion transport has been associated with cellular dysfunction, intra and extracellular edema and abnormalities of epithelial surface liquid volume. There is increasing evidence that conditions characterized by an intense local or systemic inflammatory response are associated with abnormal ion transport. This abnormal ion transport has been involved in the pathogenesis of conditions like hypovolemia due to fluid losses, hyponatremia and hypokalemia in diarrhoeal diseases, electrolyte abnormalities in pyelonephritis of early infancy, septicemia induced pulmonary edema, and in hypersecretion and edema induced by inflammatory reactions of the mucosa of the upper respiratory tract. Components of membranous ion transport systems, which have been shown to undergo a change in function during an inflammatory response include the sodium potassium ATPase, the epithelial sodium channel, the Cystic Fibrosis Transmembrane Conductance Regulator and calcium activated chloride channels and the sodium potassium chloride co-transporter. Inflammatory mediators, which influence ion transport are tumor necrosis factor, gamma interferon, interleukins, transforming growth factor, leukotrienes and bradykinin. They trigger the release of specific messengers like prostaglandins, nitric oxide and histamine which alter ion transport system function through specific receptors, intracellular second messengers and protein kinases. This review summarizes data on in vivo measurements of changes in ion transport in acute inflammatory conditions and in vitro studies, which have explored the underlying mechanisms. Potential interventions directed at a correction of the observed abnormalities are discussed.

  3. Changes in ion transport in inflammatory disease

    PubMed Central

    Eisenhut, Michael

    2006-01-01

    Ion transport is essential for maintenance of transmembranous and transcellular electric potential, fluid transport and cellular volume. Disturbance of ion transport has been associated with cellular dysfunction, intra and extracellular edema and abnormalities of epithelial surface liquid volume. There is increasing evidence that conditions characterized by an intense local or systemic inflammatory response are associated with abnormal ion transport. This abnormal ion transport has been involved in the pathogenesis of conditions like hypovolemia due to fluid losses, hyponatremia and hypokalemia in diarrhoeal diseases, electrolyte abnormalites in pyelonephritis of early infancy, septicemia induced pulmonary edema, and in hypersecretion and edema induced by inflammatory reactions of the mucosa of the upper respiratory tract. Components of membranous ion transport systems, which have been shown to undergo a change in function during an inflammatory response include the sodium potassium ATPase, the epithelial sodium channel, the Cystic Fibrosis Transmembrane Conductance Regulator and calcium activated chloride channels and the sodium potassium chloride co-transporter. Inflammatory mediators, which influence ion transport are tumor necrosis factor, gamma interferon, interleukins, transforming growth factor, leukotrienes and bradykinin. They trigger the release of specific messengers like prostaglandins, nitric oxide and histamine which alter ion transport system function through specific receptors, intracellular second messengers and protein kinases. This review summarizes data on in vivo measurements of changes in ion transport in acute inflammatory conditions and in vitro studies, which have explored the underlying mechanisms. Potential interventions directed at a correction of the observed abnormalities are discussed. PMID:16571116

  4. Expression and purification of functionally active ferrous iron transporter FeoB from Klebsiella pneumoniae.

    PubMed

    Smith, Aaron T; Sestok, Alexandrea E

    2018-02-01

    The acquisition of ferrous iron (Fe 2+ ) is an important virulence factor utilized by several hospital-acquired (nosocomial) pathogens such as Klebsiella pneumoniae to establish infection within human hosts. Virtually all bacteria use the ferrous iron transport system (Feo) to acquire ferrous iron from their environments, which are often biological niches that stabilize Fe 2+ relative to Fe 3+ . However, the details of this process remain poorly understood, likely owing to the few expression and purification systems capable of supplying sufficient quantities of the chief component of the Feo system, the integral membrane GTPase FeoB. This bottleneck has undoubtedly hampered efforts to understand this system in order to target it for therapeutic intervention. In this study, we describe the expression, solubilization, and purification of the Fe 2+ transporter from K. pneumoniae, KpFeoB. We show that this protein may be heterologously overexpressed in Escherichia coli as the host organism. After testing several different commercially-available detergents, we have developed a solubilization and purification protocol that produces milligram quantities of KpFeoB with sufficient purity for enzymatic and biophysical analyses. Importantly, we demonstrate that KpFeoB displays robust GTP hydrolysis activity (k cat GTP of ∼10 -1 s -1 ) in the absence of any additional stimulatory factors. Our findings suggest that K. pneumoniae may be capable of using its Feo system to drive Fe 2+ import in an active manner. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Homologs of the Acinetobacter baumannii AceI transporter represent a new family of bacterial multidrug efflux systems.

    PubMed

    Hassan, Karl A; Liu, Qi; Henderson, Peter J F; Paulsen, Ian T

    2015-02-10

    Multidrug efflux systems are a major cause of resistance to antimicrobials in bacteria, including those pathogenic to humans, animals, and plants. These proteins are ubiquitous in these pathogens, and five families of bacterial multidrug efflux systems have been identified to date. By using transcriptomic and biochemical analyses, we recently identified the novel AceI (Acinetobacter chlorhexidine efflux) protein from Acinetobacter baumannii that conferred resistance to the biocide chlorhexidine, via an active efflux mechanism. Proteins homologous to AceI are encoded in the genomes of many other bacterial species and are particularly prominent within proteobacterial lineages. In this study, we expressed 23 homologs of AceI and examined their resistance and/or transport profiles. MIC analyses demonstrated that, like AceI, many of the homologs conferred resistance to chlorhexidine. Many of the AceI homologs conferred resistance to additional biocides, including benzalkonium, dequalinium, proflavine, and acriflavine. We conducted fluorimetric transport assays using the AceI homolog from Vibrio parahaemolyticus and confirmed that resistance to both proflavine and acriflavine was mediated by an active efflux mechanism. These results show that this group of AceI homologs represent a new family of bacterial multidrug efflux pumps, which we have designated the proteobacterial antimicrobial compound efflux (PACE) family of transport proteins. Bacterial multidrug efflux pumps are an important class of resistance determinants that can be found in every bacterial genome sequenced to date. These transport proteins have important protective functions for the bacterial cell but are a significant problem in the clinical setting, since a single efflux system can mediate resistance to many structurally and mechanistically diverse antibiotics and biocides. In this study, we demonstrate that proteins related to the Acinetobacter baumannii AceI transporter are a new class of multidrug efflux systems which are very common in Proteobacteria: the proteobacterial antimicrobial compound efflux (PACE) family. This is the first new family of multidrug efflux pumps to be described in 15 years. Copyright © 2015 Hassan et al.

  6. Freight planning support system : final summary report

    DOT National Transportation Integrated Search

    2003-07-01

    This report summarizes the activities and the findings of the Freight Planning Support System (FPSS) project conducted for the North Jersey Transportation Planning Authority (NJTPA). The underlying purpose of the project is to allow for better projec...

  7. Highlights of 1980 activities

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Progress in the Space Transportation System is reported. A review of the Voyager 1 mission is presented along with a summary of facts gathered on its Saturn encounter. Research and development in energy technology, space tracking, and data systems is described.

  8. Automotive collision avoidance system field operational test

    DOT National Transportation Integrated Search

    2005-03-01

    The Automotive Collision Avoidance System field operational test (or ACAS FOT) program was led by General Motors (GM) under a cooperative agreement with the U.S. Department of Transportation. This report summarizes the activities of the entire progra...

  9. Announcement: Community Preventive Services Task Force Recommendation for Built Environment Interventions to Increase Physical Activity.

    PubMed

    2017-05-05

    The Community Preventive Services Task Force recently posted new information on its website: "Physical Activity: Built Environment Approaches Combining Transportation System Interventions with Land Use and Environmental Design." This information is available at https://www.thecommunityguide.org/findings/physical-activity-built-environment-approaches.

  10. Examining Changes in Radioxenon Isotope Activity Ratios during Subsurface Transport

    NASA Astrophysics Data System (ADS)

    Annewandter, Robert

    2014-05-01

    The Non-Proliferation Experiment (NPE) has demonstrated and modelled the usefulness of barometric pumping induced gas transport and subsequent soil gas sampling during On-Site inspections. Generally, gas transport has been widely studied with different numerical codes. However, gas transport of radioxenons and radioiodines in the post-detonation regime and their possible fractionation is still neglected in the open peer-reviewed literature. Atmospheric concentrations of the radioxenons Xe-135, Xe-133m, Xe-133 and Xe-131m can be used to discriminate between civilian releases (nuclear power plants or medical isotope facilities), and nuclear explosion sources. It is based on the multiple isotopic activity ratio method. Yet it is not clear whether subsurface migration of the radionuclides, with eventual release into the atmosphere, can affect the activity ratios due to fractionation. Fractionation can be caused by different mass diffusivities due to mass differences between the radionuclides. Cyclical changes in atmospheric pressure can drive subsurface gas transport. This barometric pumping phenomenon causes an oscillatoric flow in upward trending fractures or highly conductive faults which, combined with diffusion into the porous matrix, leads to a net transport of gaseous components - a so-called ratcheting effect. We use a general purpose reservoir simulator (Complex System Modelling Platform, CSMP++) which is recognized by the oil industry as leading in Discrete Fracture-Matrix (DFM) simulations. It has been applied in a range of fields such as deep geothermal systems, three-phase black oil simulations, fracture propagation in fractured, porous media, and Navier-Stokes pore-scale modelling among others. It is specifically designed to account for structurally complex geologic situation of fractured, porous media. Parabolic differential equations are solved by a continuous Galerkin finite-element method, hyperbolic differential equations by a complementary finite volume method. The parabolic and hyperbolic problem can be solved separately by operator-splitting. The resulting system of linear equations is solved by the algebraic multigrid library SAMG, developed at the Fraunhofer Institute for Algorithms and Scientific Computing, Germany. CSMP++ is developed at Montan University of Leoben, ETH Zuerich, Imperial College London and Heriot-Watt University in Edinburgh. This study examines barometric pumping-driven subsurface transport of Xe-135, Xe-133m, Xe-133, Xe-131m including I-131, I-133 and I-135 on arrival times and isotopic activity ratios. This work was funded by the CTBTO Research Award for Young Scientist and Engineers (2013).

  11. Determining the transport mechanism of an enzyme-catalytic complex metabolic network based on biological robustness.

    PubMed

    Wang, Lei

    2013-04-01

    Understanding the transport mechanism of 1,3-propanediol (1,3-PD) is of critical importance to do further research on gene regulation. Due to the lack of intracellular information, on the basis of enzyme-catalytic system, using biological robustness as performance index, we present a system identification model to infer the most possible transport mechanism of 1,3-PD, in which the performance index consists of the relative error of the extracellular substance concentrations and biological robustness of the intracellular substance concentrations. We will not use a Boolean framework but prefer a model description based on ordinary differential equations. Among other advantages, this also facilitates the robustness analysis, which is the main goal of this paper. An algorithm is constructed to seek the solution of the identification model. Numerical results show that the most possible transport way is active transport coupled with passive diffusion.

  12. A monograph of the National Space Transportation System Office (NSTSO) integration activities conducted at the NASA Lyndon B. Johnson Space Center for the EASE/ACCESS payload flown on STS 61-B

    NASA Technical Reports Server (NTRS)

    Chassay, Charles

    1987-01-01

    The integration process of activities conducted at the NASA Lyndon B. Johnson Space Center (JSC) for the Experimental Assembly of Structures in Extravehicular activity (EASE)/Assembly Concept for Construction of Erectable Space Structures (ACCESS) payload is provided as a subset to the standard payload integration process used by the NASA Space Transportation System (STS) to fly payloads on the Space Shuttle. The EASE/ACCESS payload integration activities are chronologically reviewed beginning with the initiation of the flight manifesting and integration process. The development and documentation of the EASE/ACCESS integration requirements are also discussed along with the implementation of the mission integration activities and the engineering assessments supporting the flight integration process. In addition, the STS management support organizations, the payload safety process leading to the STS 61-B flight certification, and the overall EASE/ACCESS integration schedule are presented.

  13. Single photon emission computed tomography and positron emission tomography imaging of multi-drug resistant P-glycoprotein--monitoring a transport activity important in cancer, blood-brain barrier function and Alzheimer's disease.

    PubMed

    Piwnica-Worms, David; Kesarwala, Aparna H; Pichler, Andrea; Prior, Julie L; Sharma, Vijay

    2006-11-01

    Overexpression of multi-drug resistant P-glycoprotein (Pgp) remains an important barrier to successful chemotherapy in cancer patients and impacts the pharmacokinetics of many important drugs. Pgp is also expressed on the luminal surface of brain capillary endothelial cells wherein Pgp functionally comprises a major component of the blood-brain barrier by limiting central nervous system penetration of various therapeutic agents. In addition, Pgp in brain capillary endothelial cells removes amyloid-beta from the brain. Several single photon emission computed tomography and positron emission tomography radiopharmaceutical have been shown to be transported by Pgp, thereby enabling the noninvasive interrogation of Pgp-mediated transport activity in vivo. Therefore, molecular imaging of Pgp activity may enable noninvasive dynamic monitoring of multi-drug resistance in cancer, guide therapeutic choices in cancer chemotherapy, and identify transporter deficiencies of the blood-brain barrier in Alzheimer's disease.

  14. Transport of polyamines in Drosophila S2 cells: kinetics, pharmacology and dependence on the plasma membrane proton gradient

    PubMed Central

    Romero-Calderón, Rafael; Krantz, David E.

    2005-01-01

    Polyamine transport activities have been described in diverse multicellular systems, but their bioenergetic mechanisms and molecular identity remain unclear. In the present paper, we describe a high-affinity spermine/spermidine transport activity expressed in Drosophila S2 cells. Ion-replacement experiments indicate that polyamine uptake across the cell membrane is Na+-, K+-, Cl−- and Ca2+-independent, but pH-sensitive. Additional experiments using ionophores suggest that polyamine uptake may be H+-coupled. Pharmacological experiments show that polyamine uptake in S2 cells is selectively blocked by MGBG {methylglyoxal bis(guanylhydrazone) or 1,1′-[(methylethanediylidine)-dinitrilo]diguanidine} and paraquat (N,N-dimethyl-4,4′-bipyridylium), two known inhibitors of polyamine uptake in mammalian cells. In addition, inhibitors known to block the Slc22 (solute carrier 22) family of organic anion/cation transporters inhibit spermine uptake in S2 cells. These data and the genetic tools available in Drosophila will facilitate the molecular identification and further characterization of this activity. PMID:16248856

  15. Transport of polyamines in Drosophila S2 cells: kinetics, pharmacology and dependence on the plasma membrane proton gradient.

    PubMed

    Romero-Calderón, Rafael; Krantz, David E

    2006-01-15

    Polyamine transport activities have been described in diverse multicellular systems, but their bioenergetic mechanisms and molecular identity remain unclear. In the present paper, we describe a high-affinity spermine/spermidine transport activity expressed in Drosophila S2 cells. Ion-replacement experiments indicate that polyamine uptake across the cell membrane is Na+-, K+-, Cl-- and Ca2+-independent, but pH-sensitive. Additional experiments using ionophores suggest that polyamine uptake may be H+-coupled. Pharmacological experiments show that polyamine uptake in S2 cells is selectively blocked by MGBG {methylglyoxal bis(guanylhydrazone) or 1,1'-[(methylethanediylidine)-dinitrilo]diguanidine} and paraquat (N,N-dimethyl-4,4'-bipyridylium), two known inhibitors of polyamine uptake in mammalian cells. In addition, inhibitors known to block the Slc22 (solute carrier 22) family of organic anion/cation transporters inhibit spermine uptake in S2 cells. These data and the genetic tools available in Drosophila will facilitate the molecular identification and further characterization of this activity.

  16. Materials genomics screens for adaptive ion transport behavior by redox-switchable microporous polymer membranes in lithium–sulfur batteries

    DOE PAGES

    Ward, Ashleigh L.; Doris, Sean E.; Li, Longjun; ...

    2017-04-27

    Selective ion transport across membranes is critical to the performance of many electrochemical energy storage devices. While design strategies enabling ion-selective transport are well-established, enhancements in membrane selectivity are made at the expense of ionic conductivity. To design membranes with both high selectivity and high ionic conductivity, there are cues to follow from biological systems, where regulated transport of ions across membranes is achieved by transmembrane proteins. The transport functions of these proteins are sensitive to their environment: physical or chemical perturbations to that environment are met with an adaptive response. Here we advance an analogous strategy for achieving adaptivemore » ion transport in microporous polymer membranes. Along the polymer backbone are placed redox-active switches that are activated in situ, at a prescribed electrochemical potential, by the device’s active materials when they enter the membrane’s pore. This transformation has little influence on the membrane’s ionic conductivity; however, the active-material blocking ability of the membrane is enhanced. We show that when used in lithium-sulfur batteries, these membranes offer markedly improved capacity, efficiency, and cycle-life by sequestering polysulfides in the cathode. Furthermore, the origins and implications of this behavior are explored in detail and point to new opportunities for responsive membranes in battery technology development« less

  17. Materials genomics screens for adaptive ion transport behavior by redox-switchable microporous polymer membranes in lithium–sulfur batteries

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ward, Ashleigh L.; Doris, Sean E.; Li, Longjun

    Selective ion transport across membranes is critical to the performance of many electrochemical energy storage devices. While design strategies enabling ion-selective transport are well-established, enhancements in membrane selectivity are made at the expense of ionic conductivity. To design membranes with both high selectivity and high ionic conductivity, there are cues to follow from biological systems, where regulated transport of ions across membranes is achieved by transmembrane proteins. The transport functions of these proteins are sensitive to their environment: physical or chemical perturbations to that environment are met with an adaptive response. Here we advance an analogous strategy for achieving adaptivemore » ion transport in microporous polymer membranes. Along the polymer backbone are placed redox-active switches that are activated in situ, at a prescribed electrochemical potential, by the device’s active materials when they enter the membrane’s pore. This transformation has little influence on the membrane’s ionic conductivity; however, the active-material blocking ability of the membrane is enhanced. We show that when used in lithium-sulfur batteries, these membranes offer markedly improved capacity, efficiency, and cycle-life by sequestering polysulfides in the cathode. Furthermore, the origins and implications of this behavior are explored in detail and point to new opportunities for responsive membranes in battery technology development« less

  18. Effect of insulin-like factors on glucose transport activity in unweighted rat skeletal muscle

    NASA Technical Reports Server (NTRS)

    Henriksen, Erik J.; Ritter, Leslie S.

    1993-01-01

    The effect of 3 or 6 days of unweighting on glucose transport activity, as assessed by 2-deoxyglucose uptake, in soleus strips stimulated by maximally effective concentrations of insulin, IGF-I, vanadate, or phospholipase C (PLC) is examined. Progressively increased responses to maximally effective doses of insulin or insulin-like growth factor were observed after 3 and 6 days of unweighting compared with weight matched control strips. Enhanced maximal responses to vanadate (6 days only) and PLC (3 and 6 days) were also observed. The data provide support for the existance of postreceptor binding mechanisms for the increased action of insulin on the glucose transport system in unweighted rat skeletal muscle.

  19. Ancient road transport devices: Developments from the Bronze Age to the Roman Empire

    NASA Astrophysics Data System (ADS)

    Rossi, Cesare; Chondros, Thomas G.; Milidonis, Kypros F.; Savino, Sergio; Russo, Flavio

    2016-03-01

    The development of transportation systems has significantly enhanced the welfare and modernization of society. Wooden vehicles pulled by animals have been used for land transportation since the early Bronze Age. Whole-body gharries with rigid wheels pulled by oxen appeared in Crete by 2000 BC or earlier. Horses originating from the East were depicted in early Cretan seal-rings of the same period. The two-wheeled horsedrawn chariot was one of the most important inventions in history. This vehicle provided humanity its first concept of personal transport and was the key technology of war for 2000 years. Chariots of Mycenaean and Archaic Greece with light and flexible four-spoked wheels acting as spring suspensions were depicted in vase paintings. The development of this vehicle incorporated the seeds of a primitive design activity and was important for engineering. The Trojan horse since 1194 BC and the helepolis since 700 BC were the first known machines on a wheeled base transported by horses or self-powered. Ancient engineers invented bearings lubricated with fat, and Romans introduced the ancestors of ball bearings for their wagons and carts. The historic evolution of wheeled transportation systems, along with early traction, suspension, and braking systems, is presented in this paper. Analytical and numerical methods are incorporated to analyze the most conceivable loading situations of typically reconstructed wheeled transportation systems in ancient times. Traction requirements both for horse-driven machines and the power for internal motors are also analyzed. This study can serve as a basis for further development of detailed reconstruction of transportation systems in antiquity.

  20. Direct Effects on the Membrane Potential due to "Pumps" that Transfer No Net Charge

    PubMed Central

    Schwartz, Tobias L.

    1971-01-01

    The effects of active ionic transport are included in the derivation of a general expression for the zero current membrane potential. It is demonstrated that an active transport system that transfers no net charge (nonrheogenic) may, nevertheless, directly alter the membrane potential. This effect depends upon the exchange of matter within the membrane between the active and passive diffusion regimes. Furthermore, in the presence of such exchange, the transmembrane active fluxes measured by the usual techniques and the local pumped fluxes are not identical. Several common uses of the term “electrogenic pump” are thus shown to be inconsistent with each other. These inconsistencies persist when the derivation is extended to produce a Goldman equation modified to account for active transport; however, that equation is shown to be limited by less narrow constraints on membrane heterogeneity and internal electric field than those previously required. In particular, it is applicable to idealized mosaic membranes limited by these requirements. PMID:5113004

  1. Polar transport in plants mediated by membrane transporters: focus on mechanisms of polar auxin transport.

    PubMed

    Naramoto, Satoshi

    2017-12-01

    Directional cell-to-cell transport of functional molecules, called polar transport, enables plants to sense and respond to developmental and environmental signals. Transporters that localize to plasma membranes (PMs) in a polar manner are key components of these systems. PIN-FORMED (PIN) auxin efflux carriers, which are the most studied polar-localized PM proteins, are implicated in the polar transport of auxin that in turn regulates plant development and tropic growth. In this review, the regulatory mechanisms underlying polar localization of PINs, control of auxin efflux activity, and PIN abundance at PMs are considered. Up to date information on polar-localized nutrient transporters that regulate directional nutrient movement from soil into the root vasculature is also discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Houttuynia cordata extract increased systemic exposure and liver concentrations of metformin through OCTs and MATEs in rats.

    PubMed

    You, Byoung Hoon; Chin, Young-Won; Kim, Hojun; Choi, Han Seok; Choi, Young Hee

    2018-06-01

    The synergistic activity of Houttuynia cordata ethanol extract (HCT) and metformin combination in diabetic rats has been previously reported, but the fundamental causes remain unsolved. Organic cation transporters (OCTs) and multidrug and toxin extrusion proteins (MATEs) transport metformin to the liver and kidneys. Therefore, pharmacological activity and systemic exposure of metformin in HCT-metformin combination were determined from pharmacokinetic change and glucose-lowering activity using in vitro HEK-293 cells expressing human OCTs or human MATEs and in vivo rats. HCT inhibited human OCT2 and human MATE1-mediated metformin transports in vitro. In in vivo rats, treatment with HCT and metformin for 28 days in rats (28MH rats) reduced the rat Oct2-mediated renal excretion of metformin and thereby the increased systemic exposure of metformin compared with only metformin-treated rats for 28 days (28M rats). In 28MH rats, rat Oct1-mediated metformin uptake into the liver was enhanced, leading to an improved glucose-lowering effect without hypoglycaemia compared with 28M rats. There was no impairment of renal function in HCT and metformin treatments. These results suggest that HCT-metformin combination therapy is applicable in terms of efficacy and safety. Copyright © 2018 John Wiley & Sons, Ltd.

  3. Multiple blood-brain barrier transport mechanisms limit bumetanide accumulation, and therapeutic potential, in the mammalian brain.

    PubMed

    Römermann, Kerstin; Fedrowitz, Maren; Hampel, Philip; Kaczmarek, Edith; Töllner, Kathrin; Erker, Thomas; Sweet, Douglas H; Löscher, Wolfgang

    2017-05-01

    There is accumulating evidence that bumetanide, which has been used over decades as a potent loop diuretic, also exerts effects on brain disorders, including autism, neonatal seizures, and epilepsy, which are not related to its effects on the kidney but rather mediated by inhibition of the neuronal Na-K-Cl cotransporter isoform NKCC1. However, following systemic administration, brain levels of bumetanide are typically below those needed to inhibit NKCC1, which critically limits its clinical use for treating brain disorders. Recently, active efflux transport at the blood-brain barrier (BBB) has been suggested as a process involved in the low brain:plasma ratio of bumetanide, but it is presently not clear which transporters are involved. Understanding the processes explaining the poor brain penetration of bumetanide is needed for developing strategies to improve the brain delivery of this drug. In the present study, we administered probenecid and more selective inhibitors of active transport carriers at the BBB directly into the brain of mice to minimize the contribution of peripheral effects on the brain penetration of bumetanide. Furthermore, in vitro experiments with mouse organic anion transporter 3 (Oat3)-overexpressing Chinese hamster ovary cells were performed to study the interaction of bumetanide, bumetanide derivatives, and several known inhibitors of Oats on Oat3-mediated transport. The in vivo experiments demonstrated that the uptake and efflux of bumetanide at the BBB is much more complex than previously thought. It seems that both restricted passive diffusion and active efflux transport, mediated by Oat3 but also organic anion-transporting polypeptide (Oatp) Oatp1a4 and multidrug resistance protein 4 explain the extremely low brain concentrations that are achieved after systemic administration of bumetanide, limiting the use of this drug for targeting abnormal expression of neuronal NKCC1 in brain diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Impact of a pneumatic tube system transport on hemostasis parameters measurement: the experiment of Cochin universitary hospital (AP-HP, Paris, France).

    PubMed

    Calmette, Leyla; Ibrahim, Firas; Gouin, Isabelle; Horellou, Marie-Hélène; Mazoyer, Élisabeth; Fontenay, Michaela; Flaujac, Claire

    2017-02-01

    Samples transported by pneumatic tube system are submitted to forces of acceleration and deceleration which can affect laboratory parameters. At Cochin hospital, majority of samples of hemostasis, except for platelets tests, are transported by pneumatic tube system. The objective of this study was to evaluate the impact of a pneumatic tube system (PTS) transport compared to hand-delivered transport on samples and to qualify Cochin hospital PTS according to requirements of standard ISO 15189. A bibliographical study was made and showed that pneumatic tube system particularly influences platelets tests. Four citrate tubes were collected in 5 healthy volunteers in the maternity: 2 tubes were transported by PTS and 2 others were hand-delivered to the laboratory. Five coagulation tests were analyzed: prothrombine time (PT), activated partial thromboplastin time (aPTT), factor (F) V, FVIII and platelet closure time with PFA-100TM collagen/epinephrine. For each volunteer, the results obtained by PTS and by hand-delivered transport were compared with formula usually used for biological analysis retake: 2.8 x standard deviation of reproductibility variation coefficient (SH GTA 01, COFRAC). This study did not show an impact of PTS on PT, aPTT, FV and FVIII. For PFA-100TM collagen/epinephrine, we noted an impact on 2/5 volunteers. These results, in agreement with the literature, led to the conclusion that Cochin hospital PTS is in compliance to transport samples for usual coagulation tests except platelet tests. This study allowed to issue French recommendations for PTS transport of hemostasis tubes qualification available on "Groupe français d'hémostase et thrombose" Web site.

  5. Hybrid Monte Carlo/Deterministic Methods for Accelerating Active Interrogation Modeling

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Peplow, Douglas E.; Miller, Thomas Martin; Patton, Bruce W

    2013-01-01

    The potential for smuggling special nuclear material (SNM) into the United States is a major concern to homeland security, so federal agencies are investigating a variety of preventive measures, including detection and interdiction of SNM during transport. One approach for SNM detection, called active interrogation, uses a radiation source, such as a beam of neutrons or photons, to scan cargo containers and detect the products of induced fissions. In realistic cargo transport scenarios, the process of inducing and detecting fissions in SNM is difficult due to the presence of various and potentially thick materials between the radiation source and themore » SNM, and the practical limitations on radiation source strength and detection capabilities. Therefore, computer simulations are being used, along with experimental measurements, in efforts to design effective active interrogation detection systems. The computer simulations mostly consist of simulating radiation transport from the source to the detector region(s). Although the Monte Carlo method is predominantly used for these simulations, difficulties persist related to calculating statistically meaningful detector responses in practical computing times, thereby limiting their usefulness for design and evaluation of practical active interrogation systems. In previous work, the benefits of hybrid methods that use the results of approximate deterministic transport calculations to accelerate high-fidelity Monte Carlo simulations have been demonstrated for source-detector type problems. In this work, the hybrid methods are applied and evaluated for three example active interrogation problems. Additionally, a new approach is presented that uses multiple goal-based importance functions depending on a particle s relevance to the ultimate goal of the simulation. Results from the examples demonstrate that the application of hybrid methods to active interrogation problems dramatically increases their calculational efficiency.« less

  6. The NATO Unmanned Aircraft System Human Systems Integration Guidebook

    DTIC Science & Technology

    2012-11-01

    Stakeholders HSI Management Activity Goals Project SMEs HCR Acceptance Methods & Criteria Figure 2. Overarching HSI Goal Structure ...88ABW Clear 10/21/2013; 88ABW-2013-4442 55 N NATO North Atlantic Treaty Organisation NTSB National Transportation Safety Board S SME Subject...support the organisation Personnel trained to support safety Operational Concepts HSI Technical Activity Goals Allocation of Functions

  7. Protein–Protein Interactions between Sucrose Transporters of Different Affinities Colocalized in the Same Enucleate Sieve Element

    PubMed Central

    Reinders, Anke; Schulze, Waltraud; Kühn, Christina; Barker, Laurence; Schulz, Alexander; Ward, John M.; Frommer, Wolf B.

    2002-01-01

    Suc represents the major transport form for carbohydrates in plants. Suc is loaded actively against a concentration gradient into sieve elements, which constitute the conduit for assimilate export out of leaves. Three members of the Suc transporter family with different properties were identified: SUT1, a high-affinity Suc proton cotransporter; SUT4, a low-affinity transporter; and SUT2, which in yeast is only weakly active and shows features similar to those of the yeast sugar sensors RGT2 and SNF3. Immunolocalization demonstrated that all three SUT proteins are localized in the same enucleate sieve element. Thus, the potential of Suc transporters to form homooligomers was tested by the yeast-based split-ubiquitin system. The results show that both SUT1 and SUT2 have the potential to form homooligomers. Moreover, all three Suc transporters have the potential to interact with each other. As controls, a potassium channel and a monosaccharide transporter, expressed in the plasma membrane, did not interact with the SUTs. The in vivo interaction between the functionally different Suc transporters indicates that the membrane proteins are capable of forming oligomeric structures that, like mammalian Glc transporter complexes, might be of functional significance for the regulation of transport. PMID:12119375

  8. Protonic transport through solitons in hydrogen-bonded systems

    NASA Astrophysics Data System (ADS)

    Kavitha, L.; Jayanthi, S.; Muniyappan, A.; Gopi, D.

    2011-09-01

    We offer an alternative route for investigating soliton solutions in hydrogen-bonded (HB) chains. We invoke the modified extended tangent hyperbolic function method coupled with symbolic computation to solve the governing equation of motion for proton dynamics. We investigate the dynamics of proton transfer in HB chains through bell-shaped soliton excitations, which trigger the bio-energy transport in most biological systems. This solitonic mechanism of proton transfer could play functional roles in muscular contraction, enzymatic activity and oxidative phosphorylation.

  9. Viscous streaming for locomotion and transport

    NASA Astrophysics Data System (ADS)

    Gazzola, Mattia; Parthasarathy, Tejaswin

    2017-11-01

    Rectified and oscillatory flows associated with vibrating boundaries have been employed in a variety of tasks, especially in microfluidics. The associated fluid mechanics is well known in the case of simple geometries, cylinders in particular, yet little is known in the case of active, complex systems. Motivated by potential applications in swimming mini-bots, we established an accurate and robust computational framework to investigate the flow behavior associated with oscillations of multiple and deforming shapes with an emphasis on streaming assisted locomotion and transport systems.

  10. NASA Lewis Research Center's Program on Icing Research

    NASA Technical Reports Server (NTRS)

    Reinmann, J. J.; Shaw, R. J.; Olsen, W. A., Jr.

    1982-01-01

    The helicopter and general aviation, light transport, and commercial transport aircraft share common icing requirements: highly effective, lightweight, low power consuming deicing systems, and detailed knowledge of the aeropenalties due to ice on aircraft surfaces. To meet current and future needs, NASA has a broadbased icing research program which covers both research and engineering applications, and is well coordinated with the FAA, DOD, universities, industry, and some foreign governments. Research activity in ice protection systems, icing instrumentation, experimental methods, analytical modeling, and in-flight research are described.

  11. Conserved ABC Transport System Regulated by the General Stress Response Pathways of Alpha- and Gammaproteobacteria.

    PubMed

    Herrou, Julien; Willett, Jonathan W; Czyż, Daniel M; Babnigg, Gyorgy; Kim, Youngchang; Crosson, Sean

    2017-03-01

    Brucella abortus σ E1 is an EcfG family sigma factor that regulates the transcription of dozens of genes in response to diverse stress conditions and is required for maintenance of chronic infection in a mouse model. A putative ATP-binding cassette transporter operon, bab1_0223-bab1_0226 , is among the most highly activated gene sets in the σ E1 regulon. The proteins encoded by the operon resemble quaternary ammonium-compatible solute importers but are most similar in sequence to the broadly conserved YehZYXW system, which remains largely uncharacterized. Transcription of yehZYXW is activated by the general stress sigma factor σ S in Enterobacteriaceae , which suggests a functional role for this transport system in bacterial stress response across the classes Alphaproteobacteria and Gammaproteobacteria We present evidence that B. abortus YehZYXW does not function as an importer of known compatible solutes under physiological conditions and does not contribute to the virulence defect of a σ E1 -null strain. The sole in vitro phenotype associated with genetic disruption of this putative transport system is reduced growth in the presence of high Li + ion concentrations. A crystal structure of B. abortus YehZ revealed a class II periplasmic binding protein fold with significant structural homology to Archaeoglobus fulgidus ProX, which binds glycine betaine. However, the structure of the YehZ ligand-binding pocket is incompatible with high-affinity binding to glycine betaine. This is consistent with weak measured binding of YehZ to glycine betaine and related compatible solutes. We conclude that YehZYXW is a conserved, stress-regulated transport system that is phylogenetically and functionally distinct from quaternary ammonium-compatible solute importers. IMPORTANCE Brucella abortus σ E1 regulates transcription in response to stressors encountered in its mammalian host and is necessary for maintenance of chronic infection in a mouse model. The functions of the majority of genes regulated by σ E1 remain undefined. We present a functional/structural analysis of a conserved putative membrane transport system (YehZYXW) whose expression is strongly activated by σ E1 Though annotated as a quaternary ammonium osmolyte uptake system, experimental physiological studies and measured ligand-binding properties of the periplasmic binding protein (PBP), YehZ, are inconsistent with this function. A crystal structure of B. abortus YehZ provides molecular insight into differences between bona fide quaternary ammonium osmolyte importers and YehZ-related proteins, which form a distinct phylogenetic and functional group of PBPs. Copyright © 2017 American Society for Microbiology.

  12. Effects of active warning reliability on motorist compliance at highway-railroad grade crossings.

    DOT National Transportation Integrated Search

    2007-11-01

    The Federal Railroad Administration is interested in understanding the effect of warning reliability on motorist compliance to warnings at active grade crossings. The John A. Volpe National Transportation Systems Center conducted two studies to exami...

  13. Systems thinking applied to safety during manual handling tasks in the transport and storage industry.

    PubMed

    Goode, Natassia; Salmon, Paul M; Lenné, Michael G; Hillard, Peter

    2014-07-01

    Injuries resulting from manual handling tasks represent an on-going problem for the transport and storage industry. This article describes an application of a systems theory-based approach, Rasmussen's (1997. Safety Science 27, 183), risk management framework, to the analysis of the factors influencing safety during manual handling activities in a freight handling organisation. Observations of manual handling activities, cognitive decision method interviews with workers (n=27) and interviews with managers (n=35) were used to gather information about three manual handling activities. Hierarchical task analysis and thematic analysis were used to identify potential risk factors and performance shaping factors across the levels of Rasmussen's framework. These different data sources were then integrated using Rasmussen's Accimap technique to provide an overall analysis of the factors influencing safety during manual handling activities in this context. The findings demonstrate how a systems theory-based approach can be applied to this domain, and suggest that policy-orientated, rather than worker-orientated, changes are required to prevent future manual handling injuries. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Persistent changes in the initial rate of pyruvate transport by isolated rat liver mitochondria after preincubation with adenine nucleotides and calcium ions.

    PubMed

    Vaartjes, W J; den Breejen, J N; Geelen, M J; van den Bergh, S G

    1980-08-05

    1. Preincubation of isolated rat-liver mitochondria in the presence of adenine nucleotides or Ca2+ results in definite and persistent changes in the initial rate of pyruvate transport. 2. These changes in the rate of pyruvate transport are accompanied by equally persistent changes in the opposite direction of the activity of pyruvate dehydrogenase (EC 1.2.4.1). 3. Changes of the transmembrane pH gradient and of the membrane potential, brought about by the pretreatments of the mitochondria, cannot account for the observed changes in the rate of pyruvate transport. 4. It is proposed that the pretreatment of the mitochondria directly modulates the activity of the mitochondrial pyruvate carrier. The possible regulatory role of such a modulation system is discussed.

  15. A health impact assessment of proposed public transportation service cuts and fare increases in Boston, Massachusetts (U.S.A.).

    PubMed

    James, Peter; Ito, Kate; Buonocore, Jonathan J; Levy, Jonathan I; Arcaya, Mariana C

    2014-08-07

    Transportation decisions have health consequences that are often not incorporated into policy-making processes. Health Impact Assessment (HIA) is a process that can be used to evaluate health effects of transportation policy. We present a rapid HIA, conducted over eight weeks, evaluating health and economic effects of proposed fare increases and service cuts to Boston, Massachusetts' public transportation system. We used transportation modeling in concert with tools allowing for quantification and monetization of multiple pathways. We estimated health and economic costs of proposed public transportation system changes to be hundreds of millions of dollars per year, exceeding the budget gap the public transportation authority was required to close. Significant health pathways included crashes, air pollution, and physical activity. The HIA enabled stakeholders to advocate for more modest fare increases and service cuts, which were eventually adopted by decision makers. This HIA was among the first to quantify and monetize multiple pathways linking transportation decisions with health and economic outcomes, using approaches that could be applied in different settings. Including health costs in transportation decisions can lead to policy choices with both economic and public health benefits.

  16. A Health Impact Assessment of Proposed Public Transportation Service Cuts and Fare Increases in Boston, Massachusetts (U.S.A.)

    PubMed Central

    James, Peter; Ito, Kate; Buonocore, Jonathan J.; Levy, Jonathan I.; Arcaya, Mariana C.

    2014-01-01

    Transportation decisions have health consequences that are often not incorporated into policy-making processes. Health Impact Assessment (HIA) is a process that can be used to evaluate health effects of transportation policy. We present a rapid HIA, conducted over eight weeks, evaluating health and economic effects of proposed fare increases and service cuts to Boston, Massachusetts’ public transportation system. We used transportation modeling in concert with tools allowing for quantification and monetization of multiple pathways. We estimated health and economic costs of proposed public transportation system changes to be hundreds of millions of dollars per year, exceeding the budget gap the public transportation authority was required to close. Significant health pathways included crashes, air pollution, and physical activity. The HIA enabled stakeholders to advocate for more modest fare increases and service cuts, which were eventually adopted by decision makers. This HIA was among the first to quantify and monetize multiple pathways linking transportation decisions with health and economic outcomes, using approaches that could be applied in different settings. Including health costs in transportation decisions can lead to policy choices with both economic and public health benefits. PMID:25105550

  17. 75 FR 42475 - Agency Information Collection Activities; Revision of a Currently-Approved Information Collection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-21

    ... records system 32,700 hours = 5,556,000]. Background: The Motor Carrier Safety Improvement Act of 1999 (Public Law 106-159, 113 Stat. 1749, December 9, 1999) (MCSIA) authorized the Secretary of Transportation... Transportation Equity Act: A Legacy for Users (Pub. L. 109- 59, 119 Stat. 1144, Aug. 10, 2005) (SAFETEA-LU...

  18. Estimating the potential safety benefits of intelligent transportation systems : working paper

    DOT National Transportation Integrated Search

    2000-01-01

    Highway agencies and contractors now have a new tool for estimating the remaining service life of pavements and selecting the appropriate maintenance and rehabilitation activities?ground-penetrating radar (GPR). GPR systems collect pavement layer thi...

  19. 48 CFR 47.202 - Presolicitation planning.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Presolicitation planning. 47.202 Section 47.202 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACT... Presolicitation planning. Contracting officers shall inform activities that plan to acquire transportation or...

  20. COSMIC monthly progress report

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Activities of the Computer Software Management and Information Center (COSMIC) are summarized for the month of May 1994. Tables showing the current inventory of programs available from COSMIC are presented and program processing and evaluation activities are summarized. Nine articles were prepared for publication in the NASA Tech Brief Journal. These articles (included in this report) describe the following software items: (1) WFI - Windowing System for Test and Simulation; (2) HZETRN - A Free Space Radiation Transport and Shielding Program; (3) COMGEN-BEM - Composite Model Generation-Boundary Element Method; (4) IDDS - Interactive Data Display System; (5) CET93/PC - Chemical Equilibrium with Transport Properties, 1993; (6) SDVIC - Sub-pixel Digital Video Image Correlation; (7) TRASYS - Thermal Radiation Analyzer System (HP9000 Series 700/800 Version without NASADIG); (8) NASADIG - NASA Device Independent Graphics Library, Version 6.0 (VAX VMS Version); and (9) NASADIG - NASA Device Independent Graphics Library, Version 6.0 (UNIX Version). Activities in the areas of marketing, customer service, benefits identification, maintenance and support, and dissemination are also described along with a budget summary.

  1. Physical Layer Secret-Key Generation Scheme for Transportation Security Sensor Network

    PubMed Central

    Yang, Bin; Zhang, Jianfeng

    2017-01-01

    Wireless Sensor Networks (WSNs) are widely used in different disciplines, including transportation systems, agriculture field environment monitoring, healthcare systems, and industrial monitoring. The security challenge of the wireless communication link between sensor nodes is critical in WSNs. In this paper, we propose a new physical layer secret-key generation scheme for transportation security sensor network. The scheme is based on the cooperation of all the sensor nodes, thus avoiding the key distribution process, which increases the security of the system. Different passive and active attack models are analyzed in this paper. We also prove that when the cooperative node number is large enough, even when the eavesdropper is equipped with multiple antennas, the secret-key is still secure. Numerical results are performed to show the efficiency of the proposed scheme. PMID:28657588

  2. Physical Layer Secret-Key Generation Scheme for Transportation Security Sensor Network.

    PubMed

    Yang, Bin; Zhang, Jianfeng

    2017-06-28

    Wireless Sensor Networks (WSNs) are widely used in different disciplines, including transportation systems, agriculture field environment monitoring, healthcare systems, and industrial monitoring. The security challenge of the wireless communication link between sensor nodes is critical in WSNs. In this paper, we propose a new physical layer secret-key generation scheme for transportation security sensor network. The scheme is based on the cooperation of all the sensor nodes, thus avoiding the key distribution process, which increases the security of the system. Different passive and active attack models are analyzed in this paper. We also prove that when the cooperative node number is large enough, even when the eavesdropper is equipped with multiple antennas, the secret-key is still secure. Numerical results are performed to show the efficiency of the proposed scheme.

  3. Intravital imaging of intestinal lacteals unveils lipid drainage through contractility

    PubMed Central

    Choe, Kibaek; Jang, Jeon Yeob; Park, Intae; Kim, Yeseul; Ahn, Soyeon; Park, Dae-Young; Hong, Young-Kwon; Alitalo, Kari; Koh, Gou Young; Kim, Pilhan

    2015-01-01

    Lacteals are lymphatic vessels located at the center of each intestinal villus and provide essential transport routes for lipids and other lipophilic molecules. However, it is unclear how absorbed molecules are transported through the lacteal. Here, we used reporter mice that express GFP under the control of the lymphatic-specific promoter Prox1 and a custom-built confocal microscope and performed intravital real-time visualization of the absorption and transport dynamics of fluorescence-tagged fatty acids (FAs) and various exogenous molecules in the intestinal villi in vivo. These analyses clearly revealed transepithelial absorption of these molecules via enterocytes, diffusive distribution over the lamina propria, and subsequent transport through lacteals. Moreover, we observed active contraction of lacteals, which seemed to be directly involved in dietary lipid drainage. Our analysis revealed that the smooth muscles that surround each lacteal are responsible for contractile dynamics and that lacteal contraction is ultimately controlled by the autonomic nervous system. These results indicate that the lacteal is a unique organ-specific lymphatic system and does not merely serve as a passive conduit but as an active pump that transports lipids. Collectively, using this efficient imaging method, we uncovered drainage of absorbed molecules in small intestinal villus lacteals and the involvement of lacteal contractibility. PMID:26436648

  4. Mechanism of the Antimicrobial Action of Pyrithione: Effects on Membrane Transport, ATP Levels, and Protein Synthesis

    PubMed Central

    Chandler, Carol J.; Segel, Irwin H.

    1978-01-01

    Pyrithione is a general inhibitor of membrane transport processes in fungi. A brief preincubation of Penicillium mycelia with pyrithione resulted in a marked decrease in the activities of a variety of independently regulated transport systems, including those for inorganic sulfate, inorganic phosphate, methylamine (actually, the NH4+ permease), choline-O-sulfate, glucose, l-methionine (a specific system), and several hydrophobic l-α-amino acids (the general amino acid permease). The degree of inhibition at any fixed pyrithione concentration and exposure time increased as the pH of the incubation medium was decreased. This result strongly suggests that the active species is the un-ionized molecule and that pyrithione acts by collapsing a transmembrane ΔpH driving force. The degree of transport inhibition caused by a given concentration of pyrithione increased with increasing time of exposure to the inhibitor. However, exposure time and pyrithione concentration were not reciprocally related. At “low” pyrithione concentrations, transport inhibition plateaued at some finite value. This observation suggests that the fungi can detoxify low levels of the inhibitor. The concentration of pyrithione required for a given degree of growth inhibition increased as the experimental mycelial density increased. This phenomenon was consistent with the suggestion that the fungi are capable of inactivating pyrithione. PMID:28693

  5. Dicarboxylic acid transport in Bradyrhizobium japonicum: use of Rhizobium meliloti dct gene(s) to enhance nitrogen fixation.

    PubMed Central

    Birkenhead, K; Manian, S S; O'Gara, F

    1988-01-01

    A recombinant plasmid encoding Rhizobium meliloti sequences involved in dicarboxylic acid transport (plasmid pRK290:4:46) (E. Bolton, B. Higgisson, A. Harrington, and F. O'Gara, Arch. Microbiol. 144:142-146, 1986) was used to study the relationship between dicarboxylic acid transport and nitrogen fixation in Bradyrhizobium japonicum. The expression of the dct sequences on plasmid pRK290:4:46 in B. japonicum CJ1 resulted in increased growth rates in media containing dicarboxylic acids as the sole source of carbon. In addition, strain CJ1(pRK290:4:46) exhibited enhanced succinate uptake activity when grown on dicarboxylic acids under aerobic conditions. Under free-living nitrogen-fixing conditions, strain CJ1(pRK290:4:46) exhibited higher nitrogenase (acetylene reduction) activity compared with that of the wild-type strain. This increase in nitrogenase activity also correlated with an enhanced dicarboxylic acid uptake rate under these microaerobic conditions. The regulation of dicarboxylic acid transport by factors such as metabolic inhibitors and the presence of additional carbon sources was similar in both the wild-type and the engineered strains. The implications of increasing nitrogenase activity through alterations in the dicarboxylic acid transport system are discussed. PMID:3422072

  6. Geomorphic and geochemical controls on leaf wax biomarker transport and preservation in alluvial river systems: Rio Bermejo, Argentina

    NASA Astrophysics Data System (ADS)

    Repasch, M. N.; Sachse, D.; Hovius, N.; Scheingross, J. S.; Szupiany, R. N.

    2017-12-01

    Rivers are the primary conduits for organic carbon (OC) transfer from vegetation-rich uplands to long-term sinks, and thus are responsible for significant fluxes among different reservoirs of the carbon cycle. Fluxes of terrestrial OC out of river systems are generally less than fluxes into the systems, indicating loss of OC either during active fluvial transport, during residence in the active channel belt, or in older deposits outside of the active channel belt. Sedimentary biomarkers can be used to elucidate the mechanisms of transport, preservation, and/or transformation of OC during its passage from source to sink. In this study we evaluate the influence of fluvial sediment transport on preservation of terrestrial leaf wax n-alkanes. Our natural laboratory is the Rio Bermejo in northern Argentina, which transports sediment and organic matter from the central Andes over 700 km across the foreland basin without input of foreign material from tributaries. Rapid channel migration rates in a region of flexural foreland basin uplift (the forebulge) are responsible for remobilization of floodplain sediment and terrestrial OC. By sampling suspended sediment, river bank sediment, and soil from several locations along the length of the Rio Bermejo, and analyzing the dissolved chemistry, biomarker composition, and compound-specific stable isotopes, we can evaluate the geomorphic and geochemical processes that act to influence the preservation of terrestrial biomarkers through the river system. Data suggest that concentrations of long-chain terrestrial (C25-C33) alkanes decrease downstream, while concentrations of short-chain (C15-C19) alkanes increase. This trend is corroborated by a downstream increase in suspended sediment δ13C values, suggesting a replacement of terrestrial OC by microbial OC. It is likely that microbial degradation is responsible for loss of terrestrial biomarkers as their residence time in the river system increases. Controlled laboratory experiments and analysis of modern and aged river bank sediment samples will determine where and over what timescales leaf wax alkanes are oxidized by microorganisms. With these data, we will be able to quantify the loss of OC during fluvial transit and determine the mechanisms responsible, enabling carbon cycle models to account for these losses.

  7. Evaluation of organic anion-transporting polypeptide 1B1 and CYP3A4 activities in primary human hepatocytes and HepaRG cells cultured in a dynamic three-dimensional bioreactor system.

    PubMed

    Ulvestad, Maria; Darnell, Malin; Molden, Espen; Ellis, Ewa; Åsberg, Anders; Andersson, Tommy B

    2012-10-01

    The long-term stability of liver cell functions is a major challenge when studying hepatic drug transport, metabolism, and toxicity in vitro. The aim of the present study was to investigate organic anion-transporting polypeptide (OATP) 1B1 and CYP3A4 activities in fresh primary human hepatocytes and differentiated cryopreserved HepaRG cells when cultured in a three-dimensional (3D) bioreactor system. OATP1B1 activity was determined by loss from media experiments of [(3)H]estradiol-17β-D-glucuronide and atorvastatin acid (ATA) for up to 7 days in culture. ATA metabolite formation was determined at days 3 to 4 to evaluate CYP3A4 activity. Overall, the results showed that freshly isolated human hepatocytes inoculated in the bioreactor retained OATP1B1 activity for at least 7 days, whereas in HepaRG cells no OATP1B1 activity was observed beyond day 2. The activity data were in agreement with immunohistochemical stainings, which showed that OATP1B1 protein expression was preserved for at least 9 days in fresh human hepatocytes, whereas OATP1B1 was expressed markedly lower in HepaRG cells after 9 days in culture. Fresh human hepatocytes and HepaRG cells exhibited similar CYP3A4 activity in bioreactor culture, and immunohistochemical stainings supported these findings. Activity and mRNA expression of OATP1B1 and CYP3A4 in primary human hepatocytes compared with HepaRG cells in fresh suspensions were in agreement with data obtained in bioreactor culture. In conclusion, freshly isolated human hepatocytes cultured in a 3D bioreactor system preserve both OATP1B1 and CYP3A4 activities, allowing long-term in vitro studies on drug disposition and toxicity.

  8. ABCdb: an online resource for ABC transporter repertories from sequenced archaeal and bacterial genomes.

    PubMed

    Fichant, Gwennaele; Basse, Marie-Jeanne; Quentin, Yves

    2006-03-01

    The ATP-binding cassette (ABC) transporters are one of the major classes of active transporters. They are widespread in archaea, bacteria, and eukaryota, indicating that they have arisen early in evolution. They are involved in many essential physiological processes, but the majority import or export a wide variety of compounds across cellular membranes. These systems share a common architecture composed of four (exporters) or five (importers) domains. To identify and reconstruct functional ABC transporters encoded by archaeal and bacterial genomes, we have developed a bioinformatic strategy. Cross-reference to the transport classification system is used to predict the type of compound transported. A high quality of annotation is achieved by manual verification of the predictions. However, in order to face the rapid increase in the number of published genomes, we also include analyses of genomes issuing directly from the automated strategy. Querying the database (http://www-abcdb.biotoul.fr) allows to easily retrieve ABC transporter repertories and related data. Additional query tools have been developed for the analysis of the ABC family from both functional and evolutionary perspectives.

  9. Walkability parameters, active transportation and objective physical activity: moderating and mediating effects of motor vehicle ownership in a cross-sectional study

    PubMed Central

    2012-01-01

    Background Neighborhood walkability has been associated with physical activity in several studies. However, as environmental correlates of physical activity may be context specific, walkability parameters need to be investigated separately in various countries and contexts. Furthermore, the mechanisms by which walkability affects physical activity have been less investigated. Based on previous research, we hypothesized that vehicle ownership is a potential mediator. We investigated the associations between walkability parameters and physical activity, and the mediating and moderating effects of vehicle ownership on these associations in a large sample of Swedish adults. Methods Residential density, street connectivity and land use mix were assessed within polygon-based network buffers (using Geographic Information Systems) for 2,178 men and women. Time spent in moderate to vigorous physical activity was assessed by accelerometers, and walking and cycling for transportation were assessed by the International Physical Activity Questionnaire. Associations were examined by linear regression and adjusted for socio-demographic characteristics. The product of coefficients approach was used to investigate the mediating effect of vehicle ownership. Results Residential density and land use mix, but not street connectivity, were significantly associated with time spent in moderate to vigorous physical activity and walking for transportation. Cycling for transportation was not associated with any of the walkability parameters. Vehicle ownership mediated a significant proportion of the association between the walkability parameters and physical activity outcomes. For residential density, vehicle ownership mediated 25% of the association with moderate to vigorous physical activity and 20% of the association with the amount of walking for transportation. For land use mix, the corresponding proportions were 34% and 14%. Vehicle ownership did not moderate any of the associations between the walkability parameters and physical activity outcomes. Conclusions Residential density and land use mix were associated with time spent in moderate to vigorous physical activity and walking for transportation. Vehicle ownership was a mediator but not a moderator of these associations. The present findings may be useful for policy makers and city planners when designing neighborhoods that promote physical activity. PMID:23035633

  10. Walkability parameters, active transportation and objective physical activity: moderating and mediating effects of motor vehicle ownership in a cross-sectional study.

    PubMed

    Eriksson, Ulf; Arvidsson, Daniel; Gebel, Klaus; Ohlsson, Henrik; Sundquist, Kristina

    2012-10-05

    Neighborhood walkability has been associated with physical activity in several studies. However, as environmental correlates of physical activity may be context specific, walkability parameters need to be investigated separately in various countries and contexts. Furthermore, the mechanisms by which walkability affects physical activity have been less investigated. Based on previous research, we hypothesized that vehicle ownership is a potential mediator. We investigated the associations between walkability parameters and physical activity, and the mediating and moderating effects of vehicle ownership on these associations in a large sample of Swedish adults. Residential density, street connectivity and land use mix were assessed within polygon-based network buffers (using Geographic Information Systems) for 2,178 men and women. Time spent in moderate to vigorous physical activity was assessed by accelerometers, and walking and cycling for transportation were assessed by the International Physical Activity Questionnaire. Associations were examined by linear regression and adjusted for socio-demographic characteristics. The product of coefficients approach was used to investigate the mediating effect of vehicle ownership. Residential density and land use mix, but not street connectivity, were significantly associated with time spent in moderate to vigorous physical activity and walking for transportation. Cycling for transportation was not associated with any of the walkability parameters. Vehicle ownership mediated a significant proportion of the association between the walkability parameters and physical activity outcomes. For residential density, vehicle ownership mediated 25% of the association with moderate to vigorous physical activity and 20% of the association with the amount of walking for transportation. For land use mix, the corresponding proportions were 34% and 14%. Vehicle ownership did not moderate any of the associations between the walkability parameters and physical activity outcomes. Residential density and land use mix were associated with time spent in moderate to vigorous physical activity and walking for transportation. Vehicle ownership was a mediator but not a moderator of these associations. The present findings may be useful for policy makers and city planners when designing neighborhoods that promote physical activity.

  11. 78 FR 29427 - Agency Information Collection Activities: Requests for Comments; Clearance of Renewed Approval of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-20

    ... provide annual Management Information System testing information, and to communicate with entities subject... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Agency Information Collection Activities: Requests for Comments; Clearance of Renewed Approval of Information Collection: Anti-Drug Program...

  12. 78 FR 31626 - Agency Information Collection Activities: Requests for Comments; Clearance of Renewed Approval of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-24

    ... provide annual Management Information System testing information, and to communicate with entities subject... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Agency Information Collection Activities: Requests for Comments; Clearance of Renewed Approval of Information Collection: Anti-Drug Program...

  13. Advanced aerodynamics and active controls. Selected NASA research

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Aerodynamic and active control concepts for application to commercial transport aircraft are discussed. Selected topics include in flight direct strike lightning research, triply redundant digital fly by wire control systems, tail configurations, winglets, and the drones for aerodynamic and structural testing (DAST) program.

  14. Economic impact of applying advanced technologies to transport airplanes.

    NASA Technical Reports Server (NTRS)

    Carline, A. J. K.

    1972-01-01

    Various technologies have been studied which could have application to the design of future transport airplanes. These technologies include the use of supercritical aerodynamics, composite materials, and active control systems, together with advanced engine designs that provide lower noise and pollutant levels. The economic impact of each technology is shown for a typical fleet of 195-passenger, transcontinental commercial transports cruising at both 0.9M and 0.98M. Comparisons are made with conventional transports cruising at 0.82M. Effects of combining the technologies are discussed. An R & D program aimed at bringing the technologies to fruition is outlined.

  15. Space transportation, satellite services, and space platforms

    NASA Technical Reports Server (NTRS)

    Disher, J. H.

    1979-01-01

    The paper takes a preview of the progressive development of vehicles for space transportation, satellite services, and orbital platforms. A low-thrust upper stage of either the ion engine or chemical type will be developed to transport large spacecraft and space platforms to and from GEO. The multimission spacecraft, space telescope, and other scientific platforms will require orbital serves going beyond that provided by the Shuttle's remote manipulator system, and plans call for extravehicular activity tools, improved remote manipulators, and a remote manned work station (the cherry picker).

  16. Approach to an Affordable and Productive Space Transportation System

    NASA Technical Reports Server (NTRS)

    McCleskey, Carey M.; Rhodes, Russel E.; Lepsch, Roger A.; Henderson, Edward M.; Robinson, John W.

    2012-01-01

    This paper describes an approach for creating space transportation architectures that are affordable, productive, and sustainable. The architectural scope includes both flight and ground system elements, and focuses on their compatibility to achieve a technical solution that is operationally productive, and also affordable throughout its life cycle. Previous papers by the authors and other members of the Space Propulsion Synergy Team (SPST) focused on space flight system engineering methods, along with operationally efficient propulsion system concepts and technologies. This paper follows up previous work by using a structured process to derive examples of conceptual architectures that integrate a number of advanced concepts and technologies. The examples are not intended to provide a near-term alternative architecture to displace current near-term design and development activity. Rather, the examples demonstrate an approach that promotes early investments in advanced system concept studies and trades (flight and ground), as well as in advanced technologies with the goal of enabling highly affordable, productive flight and ground space transportation systems.

  17. Kinase-dependent Regulation of Monoamine Neurotransmitter Transporters

    PubMed Central

    Bermingham, Daniel P.

    2016-01-01

    Modulation of neurotransmission by the monoamines dopamine (DA), norepinephrine (NE), and serotonin (5-HT) is critical for normal nervous system function. Precise temporal and spatial control of this signaling in mediated in large part by the actions of monoamine transporters (DAT, NET, and SERT, respectively). These transporters act to recapture their respective neurotransmitters after release, and disruption of clearance and reuptake has significant effects on physiology and behavior and has been linked to a number of neuropsychiatric disorders. To ensure adequate and dynamic control of these transporters, multiple modes of control have evolved to regulate their activity and trafficking. Central to many of these modes of control are the actions of protein kinases, whose actions can be direct or indirectly mediated by kinase-modulated protein interactions. Here, we summarize the current state of our understanding of how protein kinases regulate monoamine transporters through changes in activity, trafficking, phosphorylation state, and interacting partners. We highlight genetic, biochemical, and pharmacological evidence for kinase-linked control of DAT, NET, and SERT and, where applicable, provide evidence for endogenous activators of these pathways. We hope our discussion can lead to a more nuanced and integrated understanding of how neurotransmitter transporters are controlled and may contribute to disorders that feature perturbed monoamine signaling, with an ultimate goal of developing better therapeutic strategies. PMID:27591044

  18. Calcium- and potassium-permeable plasma membrane transporters are activated by copper in Arabidopsis root tips: linking copper transport with cytosolic hydroxyl radical production.

    PubMed

    Rodrigo-Moreno, Ana; Andrés-Colás, Nuria; Poschenrieder, Charlotte; Gunsé, Benet; Peñarrubia, Lola; Shabala, Sergey

    2013-04-01

    Transition metals such as copper can interact with ascorbate or hydrogen peroxide to form highly reactive hydroxyl radicals (OH(•) ), with numerous implications to membrane transport activity and cell metabolism. So far, such interaction was described for extracellular (apoplastic) space but not cytosol. Here, a range of advanced electrophysiological and imaging techniques were applied to Arabidopsis thaliana plants differing in their copper-transport activity: Col-0, high-affinity copper transporter COPT1-overexpressing (C1(OE) ) seedlings, and T-DNA COPT1 insertion mutant (copt1). Low Cu concentrations (10 µm) stimulated a dose-dependent Gd(3+) and verapamil sensitive net Ca(2+) influx in the root apex but not in mature zone. C1(OE) also showed a fivefold higher Cu-induced K(+) efflux at the root tip level compared with Col-0, and a reduction in basal peroxide accumulation at the root tip after copper exposure. Copper caused membrane disruptions of the root apex in C1(OE) seedlings but not in copt1 plants; this damage was prevented by pretreatment with Gd(3+) . Our results suggest that copper transport into cytosol in root apex results in hydroxyl radical generation at the cytosolic side, with a consequent regulation of plasma membrane OH(•) -sensitive Ca(2+) and K(+) transport systems. © 2012 Blackwell Publishing Ltd.

  19. Renal sympathetic nerve, blood flow, and epithelial transport responses to thermal stress.

    PubMed

    Wilson, Thad E

    2017-05-01

    Thermal stress is a profound sympathetic stress in humans; kidney responses involve altered renal sympathetic nerve activity (RSNA), renal blood flow, and renal epithelial transport. During mild cold stress, RSNA spectral power but not total activity is altered, renal blood flow is maintained or decreased, and epithelial transport is altered consistent with a sympathetic stress coupled with central volume loaded state. Hypothermia decreases RSNA, renal blood flow, and epithelial transport. During mild heat stress, RSNA is increased, renal blood flow is decreased, and epithelial transport is increased consistent with a sympathetic stress coupled with a central volume unloaded state. Hyperthermia extends these directional changes, until heat illness results. Because kidney responses are very difficult to study in humans in vivo, this review describes and qualitatively evaluates an in vivo human skin model of sympathetically regulated epithelial tissue compared to that of the nephron. This model utilizes skin responses to thermal stress, involving 1) increased skin sympathetic nerve activity (SSNA), decreased skin blood flow, and suppressed eccrine epithelial transport during cold stress; and 2) increased SSNA, skin blood flow, and eccrine epithelial transport during heat stress. This model appears to mimic aspects of the renal responses. Investigations of skin responses, which parallel certain renal responses, may aid understanding of epithelial-sympathetic nervous system interactions during cold and heat stress. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. TransMilenio, a Scalable Bus Rapid Transit System for Promoting Physical Activity.

    PubMed

    Lemoine, Pablo D; Sarmiento, Olga L; Pinzón, Jose David; Meisel, Jose D; Montes, Felipe; Hidalgo, Dario; Pratt, Michael; Zambrano, Juan Manuel; Cordovez, Juan Manuel; Zarama, Roberto

    2016-04-01

    Transport systems can play an important role in increasing physical activity (PA). Bogotá has been recognized for its bus rapid transit (BRT) system, TransMilenio (TM). To date, BRTs have been implemented in over 160 cities worldwide. The aim of this study was to assess the association between PA and the use of TM among adults in Bogotá. The study consists of a cross-sectional study conducted from 2010 to 2011 with 1000 adults. PA was measured using the International Physical Activity Questionnaire. In a subsample of 250 adults, PA was objectively measured using ActiGraph accelerometers. Analyses were conducted using multilevel logistic regression models. The use of TM was associated with meeting moderate-to-vigorous PA (MVPA). TM users were more likely to complete an average of >22 min a day of MVPA (odds ratio [OR] = 3.1, confidence interval [CI] = 95 % 1.4-7.1) and to walk for transportation for ≥150 min per week (OR = 1.5; CI = 95 % 1.1-2.0). The use of TM was associated with 12 or more minutes of MVPA (95 % CI 4.5-19.4, p < 0.0001). Associations between meeting PA recommendations and use of TM did not differ by socioeconomic status (p value = 0.106) or sex (p value = 0.288). The use of TM is a promising strategy for enhancing public health efforts to reduce physical inactivity through walking for transport. Given the expansion of BRTs, these results could inform the development of transport PA programs in low- to high-income countries.

  1. Key factors of successful JIT integration with IBS - An overview

    NASA Astrophysics Data System (ADS)

    Asri, Mohammad Azwanie Naim Mohammad; Nawi, Mohd Nasrun Mohd; Nadarajan, Santhirasegaran

    2016-08-01

    The Just-In-Time (JIT) philosophy has been used for many decades to increase productivity through waste elimination process. The purpose of this paper is to contribute to the knowledge by addressing the transportation and material delivery activities in Industrialized Building System (IBS) and integrating JIT to improve the performance of those activities. The literature review has been conducted through relevant database. It was found that there is a need for more holistic approach to be adopted to integrate JIT in IBS project. This paper discusses the key success factors for effective integration between JIT and IBS in the context of transportation and material delivery activities.

  2. The 1991 Marshall Space Flight Center research and technology

    NASA Technical Reports Server (NTRS)

    1991-01-01

    A compilation of 194 articles addressing research and technology activities at the Marshall Space Flight Center (MSFC) is given. Activities are divided into three major areas: advanced studies addressing transportation systems, space systems, and space science activities conducted primarily in the Program Development Directorate; research tasks carried out in the Space Science Laboratory; and technology programs hosted by a wide array of organizations at the Center. The theme for this year's report is 'Building for the Future'.

  3. Development Activities on Airbreathing Combined Cycle Engines

    NASA Technical Reports Server (NTRS)

    McArthur, J. Craig; Lyles, Garry (Technical Monitor)

    2000-01-01

    Contents include the following: Advanced reusable transportation(ART); aerojet and rocketdyne tests, RBCC focused concept flowpaths,fabricate flight weigh, test select components, document ART project, Istar (Integrated system test of an airbreathing rocket); combined cycle propulsion testbed;hydrocarbon demonstrator tracebility; Istar engine system and vehicle system closure study; and Istar project planning.

  4. Rural automated highway systems case study : greater Yellowstone rural ITS corridor : final report

    DOT National Transportation Integrated Search

    1998-01-01

    In cooperation with the National Automated Highway System Consortium (NAHSC), case studies are being conducted on existing transportation corridors to determine the feasibility of AHS. Initial activities by the NAHSC have focused on urbanized areas. ...

  5. Evaluation of an active wildlife-sensing and driver warning system at Trapper's Point.

    DOT National Transportation Integrated Search

    2009-04-01

    Collisions with wildlife are a serious concern on American highways. In Wyoming, the concern has prompted the Wyoming Department of Transportation : to construct an experimental wildlife detection and driver warning system at Trappers Point, north...

  6. Aircraft fuel conservation technology. Task force report, September 10, 1975

    NASA Technical Reports Server (NTRS)

    1975-01-01

    An advanced technology program is described for reduced fuel consumption in air transport. Cost benefits and estimates are given for improved engine design and components, turboprop propulsion systems, active control systems, laminar flow control, and composite primary structures.

  7. Cytoskeletal Network Morphology Regulates Intracellular Transport Dynamics.

    PubMed

    Ando, David; Korabel, Nickolay; Huang, Kerwyn Casey; Gopinathan, Ajay

    2015-10-20

    Intracellular transport is essential for maintaining proper cellular function in most eukaryotic cells, with perturbations in active transport resulting in several types of disease. Efficient delivery of critical cargos to specific locations is accomplished through a combination of passive diffusion and active transport by molecular motors that ballistically move along a network of cytoskeletal filaments. Although motor-based transport is known to be necessary to overcome cytoplasmic crowding and the limited range of diffusion within reasonable timescales, the topological features of the cytoskeletal network that regulate transport efficiency and robustness have not been established. Using a continuum diffusion model, we observed that the time required for cellular transport was minimized when the network was localized near the nucleus. In simulations that explicitly incorporated network spatial architectures, total filament mass was the primary driver of network transit times. However, filament traps that redirect cargo back to the nucleus caused large variations in network transport. Filament polarity was more important than filament orientation in reducing average transit times, and transport properties were optimized in networks with intermediate motor on and off rates. Our results provide important insights into the functional constraints on intracellular transport under which cells have evolved cytoskeletal structures, and have potential applications for enhancing reactions in biomimetic systems through rational transport network design. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  8. AMP-activated protein kinase-mediated glucose transport as a novel target of tributyltin in human embryonic carcinoma cells.

    PubMed

    Yamada, Shigeru; Kotake, Yaichiro; Sekino, Yuko; Kanda, Yasunari

    2013-05-01

    Organotin compounds such as tributyltin (TBT) are known to cause various forms of cytotoxicity, including developmental toxicity and neurotoxicity. However, the molecular target of the toxicity induced by nanomolar levels of TBT has not been identified. In the present study, we found that exposure to 100 nM TBT induced growth arrest in human pluripotent embryonic carcinoma cell line NT2/D1. Since glucose provides metabolic energy, we focused on the glycolytic system. We found that exposure to TBT reduced the levels of both glucose-6-phosphate and fructose-6-phosphate. To investigate the effect of TBT exposure on glycolysis, we examined glucose transporter (GLUT) activity. TBT exposure inhibited glucose uptake via a decrease in the level of cell surface-bound GLUT1. Furthermore, we examined the effect of AMP-activated protein kinase (AMPK), which is known to regulate glucose transport by facilitating GLUT translocation. Treatment with the potent AMPK activator, AICAR, restored the TBT-induced reduction in cell surface-bound GLUT1 and glucose uptake. In conclusion, these results suggest that exposure to nanomolar levels of TBT causes growth arrest by targeting glycolytic systems in human embryonic carcinoma cells. Thus, understanding the energy metabolism may provide new insights into the mechanisms of metal-induced cytotoxicity.

  9. Inhibition of intra-Golgi transport in vitro by mitotic kinase.

    PubMed

    Stuart, R A; Mackay, D; Adamczewski, J; Warren, G

    1993-02-25

    It has previously been shown that exocytic and endocytic membrane traffic are inhibited in mitotic mammalian cells. Here we have used a cell-free intra-Golgi transport assay supplemented with heterologous cytosols to mimic this effect in vitro. Cytosols with high histone kinase activity, made either from mitotic cells or by cyclin A treatment of interphase cells, inhibited intra-Golgi transport by up to 75%. Inhibition of transport was reversed by the kinase inhibitor staurosporine or by reduction in ATP levels leading to inactivation of histone kinase. The data indicate that cell cycle control of intra-Golgi transport is due to a reversible modification of cytosol, and this assay system may be used to study the molecular mechanism of mitotic transport inhibition in mammalian cells.

  10. The mechanics and three-dimensional internal structure of active magmatic systems: Kilauea volcano, Hawaii.

    USGS Publications Warehouse

    Ryan, M.P.

    1988-01-01

    Interpretation of abundant seismic data suggest that Kilauea's primary conduit within the upper mantle is concentrically zoned to about 34-km depth. This zoned structure is inferred to contain a central core region of relatively higher permeability, surrounded by numerous dikes that are in intermittent hydraulic communication with each other and with the central core. During periods of relatively high magma transport, the entire cross section of the conduit is utilized. During periods of relatively low to moderate transport, however, only the central core is active.-from Author

  11. Does Pedestrian Danger Mediate the Relationship between Local Walkability and Active Travel to Work?

    PubMed

    Slater, Sandy J; Nicholson, Lisa; Abu Zayd, Haytham; Chriqui, Jamie Friedman

    2016-01-01

    Environmental and policy factors play an important role in influencing people's lifestyles, physical activity (PA), and risks for developing obesity. Research suggests that more walkable communities are needed to sustain lifelong PA behavior, but there is a need to determine what local built environment features facilitate making being active the easy choice. This county-level study examined the association between local walkability (walkability and traffic calming scales), pedestrian danger, and the percent of adults who used active transport to work. Built environment and PA outcome measures were constructed for the 496 most populous counties representing 74% of the U.S. population. Geographic information system-based walkability scales were constructed and include a census of roads located within the counties using 2011 Navteq data. The pedestrian danger index (PDI) includes data collected from the Fatality Analysis Reporting System 2009-2011, and measures the likelihood of a pedestrian being hit and killed by a vehicle. Four continuous outcome measures were constructed using 2009-2013 American Community Survey county-level 5-year estimates. The measures represent the percentage of workers living in a county who worked away from home and (1) walked to work; (2) biked to work; (3) took public transit; and (4) used any form of active transport. Linear regression and mediation analyses were conducted to examine the association between walkability, PDI, and active transport. Models accounted for clustering within state with robust SEs, and controlled for median household income, families with children in poverty, race, ethnicity, urbanicity, and region. The walkability scale was significantly negatively associated with the PDI (β = -0.06, 95% CI = -0.111, -0.002). In all models, the PDI was significantly negatively associated with all active travel-related outcomes at the p < 0.01 level. The walkability scale was positively associated with all four outcomes at the p < 0.01 level. Results showed that the significant positive relationship between local walkability and the four active transport outcome measures was partially mediated by the PDI. We found no association between traffic calming, the PDI, and the active transport outcomes. Results from this study show that, at the county-level, walkability is associated with active travel, and this association is partially mediated by an index of pedestrian safety.

  12. An in vitro assay for entry into cilia reveals unique properties of the soluble diffusion barrier

    PubMed Central

    Breslow, David K.; Koslover, Elena F.; Seydel, Federica; Spakowitz, Andrew J.

    2013-01-01

    Specific proteins are concentrated within primary cilia, whereas others remain excluded. To understand the mechanistic basis of entry into cilia, we developed an in vitro assay using cells in which the plasma membrane was permeabilized, but the ciliary membrane was left intact. Using a diffusion-to-capture system and quantitative analysis, we find that proteins >9 nm in diameter (∼100 kD) are restricted from entering cilia, and we confirm these findings in vivo. Interference with the nuclear pore complex (NPC) or the actin cytoskeleton in permeabilized cells demonstrated that the ciliary diffusion barrier is mechanistically distinct from those of the NPC or the axon initial segment. Moreover, applying a mass transport model to this system revealed diffusion coefficients for soluble and membrane proteins within cilia that are compatible with rapid exploration of the ciliary space in the absence of active transport. Our results indicate that large proteins require active transport for entry into cilia but not necessarily for movement inside cilia. PMID:24100294

  13. Norepinephrine transporter heterozygous knockout mice exhibit altered transport and behavior.

    PubMed

    Fentress, H M; Klar, R; Krueger, J J; Sabb, T; Redmon, S N; Wallace, N M; Shirey-Rice, J K; Hahn, M K

    2013-11-01

    The norepinephrine (NE) transporter (NET) regulates synaptic NE availability for noradrenergic signaling in the brain and sympathetic nervous system. Although genetic variation leading to a loss of NET expression has been implicated in psychiatric and cardiovascular disorders, complete NET deficiency has not been found in people, limiting the utility of NET knockout mice as a model for genetically driven NET dysfunction. Here, we investigate NET expression in NET heterozygous knockout male mice (NET(+/-) ), demonstrating that they display an approximately 50% reduction in NET protein levels. Surprisingly, these mice display no significant deficit in NET activity assessed in hippocampal and cortical synaptosomes. We found that this compensation in NET activity was due to enhanced activity of surface-resident transporters, as opposed to surface recruitment of NET protein or compensation through other transport mechanisms, including serotonin, dopamine or organic cation transporters. We hypothesize that loss of NET protein in the NET(+/-) mouse establishes an activated state of existing surface NET proteins. The NET(+/-) mice exhibit increased anxiety in the open field and light-dark box and display deficits in reversal learning in the Morris water maze. These data suggest that recovery of near basal activity in NET(+/-) mice appears to be insufficient to limit anxiety responses or support cognitive performance that might involve noradrenergic neurotransmission. The NET(+/-) mice represent a unique model to study the loss and resultant compensatory changes in NET that may be relevant to behavior and physiology in human NET deficiency disorders. © 2013 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  14. Expression of thyroid hormone transporters and deiodinases at the brain barriers in the embryonic chicken: Insights into the regulation of thyroid hormone availability during neurodevelopment.

    PubMed

    Van Herck, Stijn L J; Delbaere, Joke; Bourgeois, Nele M A; McAllan, Bronwyn M; Richardson, Samantha J; Darras, Veerle M

    2015-04-01

    Thyroid hormones (THs) are key regulators in the development of the vertebrate brain. Therefore, TH access to the developing brain needs to be strictly regulated. The brain barriers separate the central nervous system from the rest of the body and impose specific transport mechanisms on the exchange of molecules between the general circulation and the nervous system. As such they form ideal structures for regulating TH exchange between the blood and the brain. To investigate the mechanism by which the developing brain regulates TH availability, we investigated the ontogenetic expression profiles of TH transporters, deiodinases and the TH distributor protein transthyretin (TTR) at the brain barriers during embryonic and early postnatal development using the chicken as a model. In situ hybridisation revealed expression of the TH transporters monocarboxylate transporter 8 (MCT8) and 10 (MCT10), organic anion transporting polypeptide 1C1 (OATP1C1) and L-type amino acid transporter 1 (LAT1) and the inactivating type 3 deiodinase (D3) in the choroid plexus which forms the blood-cerebrospinal fluid barrier. This was confirmed by quantitative PCR which additionally indicated strongly increasing expression of TTR as well as detectable expression of the activating type 2 deiodinase (D2) and the (in)activating type 1 deiodinase (D1). In the brain capillaries forming the blood-brain barrier in situ hybridisation showed exclusive expression of LAT1 and D2. The combined presence of LAT1 and D2 in brain capillaries suggests that the blood-brain barrier forms the main route for receptor-active T3 uptake into the embryonic chicken brain. Expression of multiple transporters, deiodinases and TTR in the choroid plexus indicates that the blood-cerebrospinal fluid barrier is also important in regulating early TH availability. The impact of these barrier systems can be deduced from the clear difference in T3 and T4 levels as well as the T3/T4 ratio between the developing brain and the general circulation. We conclude that the tight regulation of TH exchange at the brain barriers from early embryonic stages is one of the factors needed to allow the brain to develop within a relative microenvironment. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Wisconsin's study of manned Mars missions

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The design group focused on three topics: (1) Extravehicular Activities, (2) Sample Return Missions, and (3) Structural and Construction Considerations of a Manned Mars Habitat. Extravehicular Activities permit a Mars based astronaut to exit the habitat and perform mission activities in the harsh Mars environment. Today's spacesuit gloves are bulky, hard to manipulate and fatiguing. A mechanical assistance mechanism has been developed for the glove that will reduce user fatigue and increase the duration of EVA's. Oxygen supply systems are also being developed for the EVA astronaut. A scuba type system of tanked breathing air proves to be the most efficient system for short duration EVA's. A system that extracts the oxygen from atmospheric carbon dioxide can provide oxygen for long duration FVA's. Sample Return Missions require that samples be taken from several sites. Transportation considerations are addressed and two transportation schemes are proposed. The first scheme involves a lighter than air balloon. This system provides excellent range. The second design is a rover that uses tracks rather than wheels. Track rovers perform well in soft, sandy conditions. Engineering aspects of a habitat and domed greenhouse were investigated and plans for the habitat have been made. A configuration has been established and construction details have been made.

  16. Strategic Technologies for Deep Space Transport

    NASA Technical Reports Server (NTRS)

    Litchford, Ronald J.

    2016-01-01

    Deep space transportation capability for science and exploration is fundamentally limited by available propulsion technologies. Traditional chemical systems are performance plateaued and require enormous Initial Mass in Low Earth Orbit (IMLEO) whereas solar electric propulsion systems are power limited and unable to execute rapid transits. Nuclear based propulsion and alternative energetic methods, on the other hand, represent potential avenues, perhaps the only viable avenues, to high specific power space transport evincing reduced trip time, reduced IMLEO, and expanded deep space reach. Here, key deep space transport mission capability objectives are reviewed in relation to STMD technology portfolio needs, and the advanced propulsion technology solution landscape is examined including open questions, technical challenges, and developmental prospects. Options for potential future investment across the full compliment of STMD programs are presented based on an informed awareness of complimentary activities in industry, academia, OGAs, and NASA mission directorates.

  17. Toward a community coastal sediment transport modeling system: the second workshop

    USGS Publications Warehouse

    Sherwood, Christopher R.; Harris, Courtney K.; Geyer, W. Rockwell; Butman, Bradford

    2002-01-01

    Models for transport and the long-term fate of particles in coastal waters are essential for a variety of applications related to commerce, defense, public health, and the quality of the marine environment. Examples include: analysis of waste disposal and transport and the fate of contaminated materials; evaluation of burial rates for naval mines or archaeological artifacts; prediction of water-column optical properties; analysis of transport and the fate of biological particles; prediction of coastal flooding and coastal erosion; evaluation of impacts of sea-level or wave-climate changes and coastal development; planning for construction and maintenance of navigable waterways; evaluation of habitat for commercial fisheries; evaluation of impacts of natural or anthropogenic changes in coastal conditions on recreational activities; and design of intakes and outfalls for sewage treatment, cooling systems, and desalination plants.

  18. Toward a community coastal sediment transport modeling system: The second workshop

    NASA Astrophysics Data System (ADS)

    Sherwood, Christopher R.; Harris, Courtney K.; Rockwell Geyer, W.; Butman, Bradford

    Models for transport and the long-term fate of particles in coastal waters are essential for a variety of applications related to commerce, defense, public health, and the quality of the marine environment. Examples include: analysis of waste disposal and transport and the fate of contaminated materials; evaluation of burial rates for naval mines or archaeological artifacts; prediction of water-column optical properties; analysis of transport and the fate of biological particles; prediction of coastal flooding and coastal erosion; evaluation of impacts of sea-level or wave-climate changes and coastal development; planning for construction and maintenance of navigable waterways; evaluation of habitat for commercial fisheries; evaluation of impacts of natural or anthropogenic changes in coastal conditions on recreational activities; and design of intakes and outfalls for sewage treatment, cooling systems, and desalination plants.

  19. Orbit Transfer Systems with Emphasis on Shuttle Applications, 1986-1991

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A systems study is presented for a transportation system which will follow the interim upper stage and spinning solid upper stage. Included are concepts, concept comparisons, trends, parametric data, etc. associated with the future system. Relevant technical and programmatic information is developed. This information is intended to focus future activity to identify attractive options and to summarize the major issues associated with the future development of the system. To establish a common basis for identifying current transportation concepts, an orbit transfer vehicle (OTV) is defined as a propulsive (velocity producing) rocket or stage. When used with a crew transfer module, a manned sortie module or other payloads, the combination becomes an orbit transfer system (OTS). Standardization of OTV's and OTS's is required.

  20. Regulation of transport processes across the tonoplast

    PubMed Central

    Neuhaus, H. Ekkehard; Trentmann, Oliver

    2014-01-01

    In plants, the vacuole builds up the cellular turgor and represents an important component in cellular responses to diverse stress stimuli. Rapid volume changes of cells, particularly of motor cells, like guard cells, are caused by variation of osmolytes and consequently of the water contents in the vacuole. Moreover, directed solute uptake into or release out of the large central vacuole allows adaptation of cytosolic metabolite levels according to the current physiological requirements and specific cellular demands. Therefore, solute passage across the vacuolar membrane, the tonoplast, has to be tightly regulated. Important principles in vacuolar transport regulation are changes of tonoplast transport protein abundances by differential expression of genes or changes of their activities, e.g., due to post-translational modification or by interacting proteins. Because vacuolar transport is in most cases driven by an electro-chemical gradient altered activities of tonoplast proton pumps significantly influence vacuolar transport capacities. Intense studies on individual tonoplast proteins but also unbiased system biological approaches have provided important insights into the regulation of vacuolar transport. This short review refers to selected examples of tonoplast proteins and their regulation, with special focus on protein phosphorylation. PMID:25309559

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