Science.gov

Sample records for 5-6 altitude steps

  1. Observations of Negative Leader Stepping Mechanisms in Altitude Triggered Lightning

    NASA Astrophysics Data System (ADS)

    Biagi, C. J.; Hill, J. D.; Jordan, D. M.; Uman, M. A.

    2011-12-01

    On 27 May 2009, at approximately 20:19:36 UTC, an attempt at classically triggering lightning with a grounded wire resulted in an altitude triggered lightning after the wire broke during the rocket ascent. The lightning was triggered at the International Center for Lightning Research and Testing at the Camp Blanding in north-central Florida. The wire extension began when the upward pointing electric field magnitude at ground was about 6 kV m-1. The triggered lightning contained nine leader/return stroke sequences, including a downward negative stepped leader that developed from the bottom of the triggering wire to the ground and the return stroke that followed. The downward negative stepped leader initiated from the bottom of the triggering wire at a height of about 133 m above ground level, and connected to ground in about 585 μs. A high-speed video camera operating at a framing rate of 108 kfps (9.25 μs per frame) imaged the stepped leader development from a height of about 120 m to 70 m in 38 frames (350 μs), and from a height of about 30 m to 20 m in 6 frames (56 μs). There was evidence of step formation mechanisms in the leader's streamer zone in seven of the high-speed video images. More specifically, secondary segments of luminosity that were separate from and ahead of the primary leader channel were observed that are similar to those reported in Biagi et al. [2009, 2010] and Hill et al. [2011]. These segments of luminosity are interpreted to have been either space stems or space leaders. There were five apparent space stems (two co-existing parallel to each other in a single frame), and three apparent space leaders. The five luminous segments that are thought to have been space stems were 1 to 2 m in length, and extended to maximum distances from the primary leader channel between 3 and 5 m (4.4 m on average). The three luminous segments that are thought to have been space leaders were 2, 3 and 6 m in length, and extended to maximum distances from the

  2. Preliminary breakdown of intracloud lightning: Initiation altitude, propagation speed, pulse train characteristics, and step length estimation

    NASA Astrophysics Data System (ADS)

    Wu, Ting; Yoshida, Satoru; Akiyama, Yasuhiro; Stock, Michael; Ushio, Tomoo; Kawasaki, Zen

    2015-09-01

    Using a low-frequency lightning location system comprising 11 sites, we located preliminary breakdown (PB) processes in 662 intracloud (IC) lightning flashes during the summer of 2013 in Osaka area of Japan. On the basis of three-dimensional location results, we studied initiation altitude and upward propagation speed of PB processes. PB in most IC flashes has an initiation altitude that ranges from 5 to 10 km with an average of 7.8 km. Vertical speed ranges from 0.5 to 17.8 × 105 m/s with an average of 4.0 × 105 m/s. Vertical speed is closely related with initiation altitude, with IC flashes initiated at higher altitude having lower vertical speed during PB stage. Characteristics of PB pulse trains including pulse rate, pulse amplitude, and pulse width are also analyzed. The relationship between pulse rate and vertical speed has the strongest correlation, suggesting that each PB pulse corresponds to one step of the initial leader during the PB stage. Pulse rate, pulse amplitude, and pulse width all show decreasing trends with increasing initiation altitude and increasing trends with increasing vertical speed. Using a simple model, the step length of the initial leader during the PB stage is estimated. Most of initial leaders have step lengths that range from 40 to 140 m with an average of 113 m. Estimated step length has a strong correlation with initiation altitude, indicating that leaders initiated at higher altitude have longer steps. Based on the results of this study, we speculate that above certain altitude (~12 km), initial leaders in PB stages of IC flashes may only have horizontal propagations. PB processes at very high altitude may also have very weak radiation, so detecting and locating them would be relatively difficult.

  3. A ONE STEP METHOD FOR THE DETERMINATION OF CARBAMATE PESTICIDES BY DERIVATIZATION WITH ALPHA-BROMO-2,3,4,5,6-PENTAFLUOROTOLUENE

    EPA Science Inventory

    A procedure was developed for the determination of trace quantities of a broad range of carbamate pesticides. The carbamates were hydrolyzed and derivatized in a single step, using alkali and alpha-bromo-2,3,4,5,6-pentafluorotoluene (PFBB), and were subsequently analyzed using el...

  4. Sgs1's roles in DNA end resection, HJ dissolution, and crossover suppression require a two-step SUMO regulation dependent on Smc5/6

    PubMed Central

    Bermúdez-López, Marcelino; Villoria, María Teresa; Esteras, Miguel; Jarmuz, Adam; Torres-Rosell, Jordi; Clemente-Blanco, Andres; Aragon, Luis

    2016-01-01

    The RecQ helicase Sgs1 plays critical roles during DNA repair by homologous recombination, from end resection to Holliday junction (HJ) dissolution. Sgs1 has both pro- and anti-recombinogenic roles, and therefore its activity must be tightly regulated. However, the controls involved in recruitment and activation of Sgs1 at damaged sites are unknown. Here we show a two-step role for Smc5/6 in recruiting and activating Sgs1 through SUMOylation. First, auto-SUMOylation of Smc5/6 subunits leads to recruitment of Sgs1 as part of the STR (Sgs1–Top3–Rmi1) complex, mediated by two SUMO-interacting motifs (SIMs) on Sgs1 that specifically recognize SUMOylated Smc5/6. Second, Smc5/6-dependent SUMOylation of Sgs1 and Top3 is required for the efficient function of STR. Sgs1 mutants impaired in recognition of SUMOylated Smc5/6 (sgs1-SIMΔ) or SUMO-dead alleles (sgs1-KR) exhibit unprocessed HJs at damaged replication forks, increased crossover frequencies during double-strand break repair, and severe impairment in DNA end resection. Smc5/6 is a key regulator of Sgs1's recombination functions. PMID:27298337

  5. Estimation of source altitudes of Terrestrial Gamma-ray Flashes produced during the stepping of lighting leaders

    NASA Astrophysics Data System (ADS)

    Xu, W.; Celestin, S. J.; Pasko, V. P.

    2011-12-01

    Terrestrial Gamma-ray Flashes (TGFs) are high-energy photon bursts originating from the Earth's atmosphere. After their discovery in 1994 by the Burst and Transient Source Experiment (BATSE) detector aboard the Compton Gamma-Ray Observatory [Fishman et al., Science, 264, 1313, 1994], this phenomenon has been further observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) [Smith et al., Science, 307, 1085, 2005], the Fermi Gamma-ray Space Telescope [Briggs et al., JGR, 115, A07323, 2010] and the Astrorivelatore Gamma a Immagini Leggero (AGILE) satellite [Marisaldi et al., JGR, 115, A00E13, 2010]. Photon spectra corresponding to well-established model of relativistic runaway electron avalanches (RREAs) usually provide a very good agreement with satellite observations [Dwyer and Smith, GRL, 32, L22804, 2005]. However, it has been suggested that long unbranched +IC lightning leaders could produce a sufficient number of energetic electrons to explain TGFs without invoking further amplification in RREAs [Celestin and Pasko, JGR, 116, A03315, 2011]. We have developed a detailed Monte Carlo model to simulate photon transport in the atmosphere. In the present study, we simulate photons with energies ranging from ~10 keV to ~100 MeV. Three different types of collisions are taken into account: Photoelectric absorption (main process for energies <30 keV), Compton scattering (main process for energies from 30 keV to 30 MeV) and pair production (main process for energies >30 MeV). The initial photons are generated from energetic electrons produced by lightning during negative corona flashes. We utilize electron energy distributions derived from the most recent Monte Carlo runaway models developed at Penn State to define spectral properties of these photons. The propagation of these photons is simulated up to 500 km, which is the typical altitude of satellites detecting TGFs. Based on the mechanism of direct TGFs production in the lightning leaders, we will

  6. Weather Requirements and Procedures for Step 1: High Altitude Long Endurance (HALE) Unmanned Aircraft System (UAS) Flight Operations in the National Air Space (NAS)

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This cover sheet is for version 2 of the weather requirements document along with Appendix A. The purpose of the requirements document was to identify and to list the weather functional requirements needed to achieve the Access 5 vision of "operating High Altitude, Long Endurance (HALE) Unmanned Aircraft Systems (UAS) routinely, safely, and reliably in the National Airspace System (NAS) for Step 1." A discussion of the Federal Aviation Administration (FAA) references and related policies, procedures, and standards is provided as basis for the recommendations supported within this document. Additional procedures and reference documentation related to weather functional requirements is also provided for background. The functional requirements and related information are to be proposed to the FAA and various standards organizations for consideration and approval. The appendix was designed to show that sources of flight weather information are readily available to UAS pilots conducting missions in the NAS. All weather information for this presentation was obtained from the public internet.

  7. 4 CFR 5.6 - Allowances.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 4 Accounts 1 2010-01-01 2010-01-01 false Allowances. 5.6 Section 5.6 Accounts GOVERNMENT ACCOUNTABILITY OFFICE PERSONNEL SYSTEM COMPENSATION § 5.6 Allowances. The provisions of chapter 59 of title 5, U.S. Code and the implementing regulations for the Executive Branch apply to Government...

  8. 1 CFR 5.6 - Daily publication.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 1 General Provisions 1 2013-01-01 2012-01-01 true Daily publication. 5.6 Section 5.6 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.6 Daily publication. There shall be an edition of the Federal Register published for each official Federal working day....

  9. 1 CFR 5.6 - Daily publication.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 1 General Provisions 1 2012-01-01 2012-01-01 false Daily publication. 5.6 Section 5.6 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.6 Daily publication. There shall be an edition of the Federal Register published for each official Federal working day....

  10. 1 CFR 5.6 - Daily publication.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 1 General Provisions 1 2014-01-01 2012-01-01 true Daily publication. 5.6 Section 5.6 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.6 Daily publication. There shall be an edition of the Federal Register published for each official Federal working day....

  11. 1 CFR 5.6 - Daily publication.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 1 General Provisions 1 2011-01-01 2011-01-01 false Daily publication. 5.6 Section 5.6 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.6 Daily publication. There shall be an edition of the Federal Register published for each official Federal working day....

  12. 1 CFR 5.6 - Daily publication.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 1 General Provisions 1 2010-01-01 2010-01-01 false Daily publication. 5.6 Section 5.6 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.6 Daily publication. There shall be an edition of the Federal Register published for each official Federal working day....

  13. 43 CFR 1610.5-6 - Revision.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Revision. 1610.5-6 Section 1610.5-6 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR GENERAL MANAGEMENT (1000) PLANNING, PROGRAMMING, BUDGETING Resource...

  14. 36 CFR 5.6 - Commercial vehicles.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Commercial vehicles. 5.6... COMMERCIAL AND PRIVATE OPERATIONS § 5.6 Commercial vehicles. (a) The term “Commercial vehicle” as used in... used in connection with any business. (b) The use of government roads within park areas by...

  15. 11 CFR 5.6 - Fees.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... CFR 5.6(a) include, but are not limited to, the following: Advisory Opinion Index Report on Financial... ELECTION COMMISSION ACCESS TO PUBLIC DISCLOSURE DIVISION DOCUMENTS § 5.6 Fees. (a)(1) Fees will be charged... Time/Photocopying Time Clerical: First 1/2 hour is free; remaining time costs $4.50 per each half...

  16. 11 CFR 5.6 - Fees.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... CFR 5.6(a) include, but are not limited to, the following: Advisory Opinion Index Report on Financial... ELECTION COMMISSION ACCESS TO PUBLIC DISCLOSURE DIVISION DOCUMENTS § 5.6 Fees. (a)(1) Fees will be charged... Time/Photocopying Time Clerical: First 1/2 hour is free; remaining time costs $4.50 per each half...

  17. 36 CFR 5.6 - Commercial vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Commercial vehicles. 5.6... COMMERCIAL AND PRIVATE OPERATIONS § 5.6 Commercial vehicles. (a) The term “Commercial vehicle” as used in... other vehicles when used in transporting movable property for a fee or profit, either as a direct...

  18. 36 CFR 5.6 - Commercial vehicles.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Commercial vehicles. 5.6... COMMERCIAL AND PRIVATE OPERATIONS § 5.6 Commercial vehicles. (a) The term “Commercial vehicle” as used in... other vehicles when used in transporting movable property for a fee or profit, either as a direct...

  19. 41 CFR 51-5.6 - Shipping.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Shipping. 51-5.6 Section 51-5.6 Public Contracts and Property Management Other Provisions Relating to Public Contracts COMMITTEE FOR PURCHASE FROM PEOPLE WHO ARE BLIND OR SEVERELY DISABLED 5-CONTRACTING REQUIREMENTS §...

  20. New synthesis of 5,6-benzindole

    SciTech Connect

    Shagalov, L.B.; Ostapchuk, G.M.; Ivanova, T.M.; Suvorov, N.N.

    1987-12-01

    A method has been developed for the synthesis of linear 5,6-benzindole by reduction of N-acetyl-5,6-benzindoxy with NaBH/sub 4/ and subsequent hydrolysis of the N-acetyl group. The PMR spectra were obtained on a Varian H-100 spectrometer in solutions of acetone-d/sub 6/ and chloroform-d/sub 3/ with TMA as internal standard. IR spectra were recorded on a Perkin-Elmer 180 spectrometer in KBr disks or in chloroform solutions in standard cells. TLC was conducted on Silufol UV-254 plates, with chloroform as eluent.

  1. 44 CFR 5.6 - Congressional information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Congressional information. 5... HOMELAND SECURITY GENERAL PRODUCTION OR DISCLOSURE OF INFORMATION General Provisions § 5.6 Congressional information. Nothing in this part authorizes withholding information from the Congress except when...

  2. 11 CFR 5.6 - Fees.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... CFR 5.6(a) include, but are not limited to, the following: Advisory Opinion Index Report on Financial... ID numbers. Requests for more than 20 ID numbers will cost $.05 for each ID number requested. E Index (Parts 1-4)—Candidate Index of Supporting Documents—No charge for requests of 20 or fewer candidate...

  3. 44 CFR 5.6 - Congressional information.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 44 Emergency Management and Assistance 1 2013-10-01 2013-10-01 false Congressional information. 5... HOMELAND SECURITY GENERAL PRODUCTION OR DISCLOSURE OF INFORMATION General Provisions § 5.6 Congressional information. Nothing in this part authorizes withholding information from the Congress except when...

  4. 11 CFR 5.6 - Fees.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... CFR 5.6(a) include, but are not limited to, the following: Advisory Opinion Index Report on Financial... ID numbers. Requests for more than 20 ID numbers will cost $.05 for each ID number requested. E Index (Parts 1-4)—Candidate Index of Supporting Documents—No charge for requests of 20 or fewer candidate...

  5. 11 CFR 5.6 - Fees.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... CFR 5.6(a) include, but are not limited to, the following: Advisory Opinion Index Report on Financial... ID numbers. Requests for more than 20 ID numbers will cost $.05 for each ID number requested. E Index (Parts 1-4)—Candidate Index of Supporting Documents—No charge for requests of 20 or fewer candidate...

  6. Re-analysis of protein data reveals the germination pathway and up accumulation mechanism of cell wall hydrolases during the radicle protrusion step of seed germination in Podophyllum hexandrum- a high altitude plant

    PubMed Central

    Dogra, Vivek; Bagler, Ganesh; Sreenivasulu, Yelam

    2015-01-01

    Podophyllum hexandrum Royle is an important high-altitude plant of Himalayas with immense medicinal value. Earlier, it was reported that the cell wall hydrolases were up accumulated during radicle protrusion step of Podophyllum seed germination. In the present study, Podophyllum seed Germination protein interaction Network (PGN) was constructed by using the differentially accumulated protein (DAP) data set of Podophyllum during the radicle protrusion step of seed germination, with reference to Arabidopsis protein–protein interaction network (AtPIN). The developed PGN is comprised of a giant cluster with 1028 proteins having 10,519 interactions and a few small clusters with relevant gene ontological signatures. In this analysis, a germination pathway related cluster which is also central to the topology and information dynamics of PGN was obtained with a set of 60 key proteins. Among these, eight proteins which are known to be involved in signaling, metabolism, protein modification, cell wall modification, and cell cycle regulation processes were found commonly highlighted in both the proteomic and interactome analysis. The systems-level analysis of PGN identified the key proteins involved in radicle protrusion step of seed germination in Podophyllum. PMID:26579141

  7. High-Altitude Illness

    MedlinePlus

    ... altitude illness: Acute mountain sickness High-altitude pulmonary edema (also called HAPE), which affects the lungs High-altitude cerebral edema (also called HACE), which affects the brain These ...

  8. 6 CFR 5.6 - Responses to requests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 6 Domestic Security 1 2014-01-01 2014-01-01 false Responses to requests. 5.6 Section 5.6 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY DISCLOSURE OF RECORDS AND INFORMATION Freedom of Information Act § 5.6 Responses to requests. (a) Acknowledgements of requests. On receipt of a request, a component ordinarily...

  9. Ears and Altitude

    MedlinePlus

    ... Meeting Calendar Find an ENT Doctor Near You Ears and Altitude Ears and Altitude Patient Health Information ... uncomfortable feeling of fullness or pressure. Why do ears pop? Normally, swallowing causes a little click or ...

  10. Fulminant high altitude blindness.

    PubMed

    Mashkovskiy, Evgeny; Szawarski, Piotr; Ryzhkov, Pavel; Goslar, Tomaz; Mrak, Irena

    2016-06-01

    Prolonged altitude exposure even with acclimatization continues to present a physiological challenge to all organ systems including the central nervous system. We describe a case of a 41-year-old Caucasian female climber who suffered severe visual loss that was due to possible optic nerve pathology occurring during a high altitude expedition in the Himalayas. This case is atypical of classic high altitude cerebral oedema and highlights yet another danger of prolonged sojourn at extreme altitudes. PMID:27601532

  11. High altitude decelerator systems

    NASA Technical Reports Server (NTRS)

    Silbert, Mendel N.; Moltedo, A. David; Gilbertson, Gaylord S.

    1989-01-01

    High Altitude Decelerator Systems are used to provide a stable descending platform when deployed from a sounding rocket at altitudes greater than 40 kilometers allowing a scientific mission to be conducted in a specific altitude region. The High Altitude Decelerator is designed to provide a highly stable, high drag area system packed in a minimum volume to deploy successfully from a sounding rocket. Deployment altitudes greater than 100 kilometers have been successfully demonstrated at dynamic pressures as low as 0.004 pounds per square foot.

  12. High-altitude headache.

    PubMed

    Marmura, Michael J; Hernandez, Pablo Bandres

    2015-05-01

    High-altitude headache is one of many neurological symptoms associated with the ascent to high altitudes. Cellular hypoxia due to decreased barometric pressure seems to be the common final pathway for headache as altitude increases. Susceptibility to high-altitude headache depends on genetic factors, history of migraine, and acclimatization, but symptoms of acute mountain sickness are universal at very high altitudes. This review summarizes the pathophysiology of acute mountain sickness and high-altitude headache as well as the evidence for treatment and prevention with different drugs and devices which may be useful for regular and novice mountaineers. This includes an examination of other headache disorders which may mimic high-altitude headache. PMID:25795155

  13. Delirium at high altitude.

    PubMed

    Basnyat, Buddha

    2002-01-01

    A 35-year-old man on a trek to the Mount Everest region of Nepal presented with a sudden, acute confusional state at an altitude of about 5000 m. Although described at higher altitudes, delirium presenting alone has not been documented at 5000 m or at lower high altitudes. The differential diagnosis which includes acute mountain sickness and high altitude cerebral edema is discussed. Finally, the importance of travelling with a reliable partner and using proper insurance is emphasized in treks to the Himalayas. PMID:12006167

  14. [Mountaineering and altitude sickness].

    PubMed

    Maggiorini, M

    2001-06-01

    Almost every second trekker or climber develops two to three symptoms of the high altitude illness after a rapid ascent (> 300 m/day) to an altitude above 4000 m. We distinguish two forms of high altitude illness, a cerebral form called acute mountain sickness and a pulmonary form called high altitude pulmonary edema. Essentially, acute mountain sickness is self-limiting and benign. Its symptoms are mild to moderate headache, loss of appetite, nausea, dizziness and insomnia. Nausea rarely progresses to vomiting, but if it does, this may anticipate a progression of the disease into the severe form of acute mountain sickness, called high altitude cerebral edema. Symptoms and signs of high altitude cerebral edema are severe headache, which is not relieved by acetaminophen, loss of movement coordination, ataxia and mental deterioration ending in coma. The mechanisms leading to acute mountain sickness are not very well understood; the loss of cerebral autoregulation and a vasogenic type of cerebral edema are being discussed. High altitude pulmonary edema presents in roughly twenty percent of the cases with mild symptoms of acute mountain sickness or even without any symptoms at all. Symptoms associated with high altitude pulmonary edema are incapacitating fatigue, chest tightness, dyspnoe at the minimal effort that advances to dyspnoe at rest and orthopnoe, and a dry non-productive cough that progresses to cough with pink frothy sputum due to hemoptysis. The hallmark of high altitude pulmonary edema is an exaggerated hypoxic pulmonary vasoconstriction. Successful prophylaxis and treatment of high altitude pulmonary edema using nifedipine, a pulmonary vasodilator, indicates that pulmonary hypertension is crucial for the development of high altitude pulmonary edema. The primary treatment of high altitude illness consists in improving hypoxemia and acclimatization. For prophylaxis a slow ascent at a rate of 300 m/day is recommended, if symptoms persist, acetazolamide at a

  15. Ear - blocked at high altitudes

    MedlinePlus

    High altitudes and blocked ears; Flying and blocked ears; Eustachian tube dysfunction - high altitude ... you are going up or coming down from high altitudes. Chewing gum the entire time you are changing ...

  16. Endurance training at altitude.

    PubMed

    Saunders, Philo U; Pyne, David B; Gore, Christopher J

    2009-01-01

    Since the 1968 Olympic Games when the effects of altitude on endurance performance became evident, moderate altitude training ( approximately 2000 to 3000 m) has become popular to improve competition performance both at altitude and sea level. When endurance athletes are exposed acutely to moderate altitude, a number of physiological responses occur that can comprise performance at altitude; these include increased ventilation, increased heart rate, decreased stroke volume, reduced plasma volume, and lower maximal aerobic power ((.)Vo(2max)) by approximately 15% to 20%. Over a period of several weeks, one primary acclimatization response is an increase in the volume of red blood cells and consequently of (.)Vo(2max). Altitudes > approximately 2000 m for >3 weeks and adequate iron stores are required to elicit these responses. However, the primacy of more red blood cells for superior sea-level performance is not clear-cut since the best endurance athletes in the world, from Ethiopia (approximately 2000 to 3000 m), have only marginally elevated hemoglobin concentrations. The substantial reduction in (.)Vo(2max) of athletes at moderate altitude implies that their training should include adequate short-duration (approximately 1 to 2 min), high-intensity efforts with long recoveries to avoid a reduction in race-specific fitness. At the elite level, athlete performance is not dependent solely on (.)Vo(2max), and the "smallest worthwhile change" in performance for improving race results is as little as 0.5%. Consequently, contemporary statistical approaches that utilize the concept of the smallest worthwhile change are likely to be more appropriate than conventional statistical methods when attempting to understand the potential benefits and mechanisms of altitude training. PMID:19519223

  17. CAT altitude avoidance system

    NASA Technical Reports Server (NTRS)

    Gary, B. L. (Inventor)

    1982-01-01

    A method and apparatus are provided for indicating the altitude of the tropopause or of an inversion layer wherein clear air turbulence (CAT) may occur, and the likely severity of any such CAT, includes directing a passive microwave radiometer on the aircraft at different angles with respect to the horizon. The microwave radiation measured at a frequency of about 55 GHz represents the temperature of the air at an ""average'' range of about 3 kilometers, so that the sine of the angle of the radiometer times 3 kilometers equals the approximate altitude of the air whose temperature is measured. A plot of altitude (with respect to the aircraft) versus temperature of the air at that altitude, can indicate when an inversion layer is present and can indicate the altitude of the tropopause or of such an inversion layer. The plot can also indicate the severity of any CAT in an inversion layer. If CAT has been detected in the general area, then the aircraft can be flown at an altitude to avoid the tropopause or inversion layer.

  18. E. coli QueD is a 6-carboxy-5,6,7,8-tetrahydropterin synthase†

    PubMed Central

    McCarty, Reid M.; Somogyi, Árpád; Bandarian, Vahe

    2009-01-01

    To elucidate the early steps required during biosynthesis of a broad class of 7-deazapurine containing natural products, we have studied the reaction catalyzed by Escherichia coli QueD, a 6-pyruvoyl-5,6,7,8-tetrahydropterin synthase (PTPS) homolog possibly involved in queuosine biosynthesis. While mammalian PTPS homologs convert 7,8-dihydroneopterin triphosphate (H2NTP) to 6-pyruvoyltetrahydropterin (PPH4) in biopterin biosynthesis, E. coli QueD catalyzes the conversion of H2NTP to 6-carboxy-5,6,7,8-tetrahydropterin (CPH4). E. coli QueD can also convert PPH4 and sepiapterin to CPH4, allowing a mechanism to be proposed. PMID:19231875

  19. Altitude Modulates Concussion Incidence

    PubMed Central

    Smith, David W.; Myer, Gregory D.; Currie, Dustin W.; Comstock, R. Dawn; Clark, Joseph F.; Bailes, Julian E.

    2013-01-01

    Background: Recent research indicates that the volume and/or pressure of intracranial fluid, a physiology affected by one’s altitude (ie, elevation above sea level), may be associated with the likelihood and/or severity of a concussion. The objective was to employ an epidemiological field investigation to evaluate the relationship between altitude and concussion rate in high school sports. Hypothesis: Because of the physiologies that occur during acclimatization, including a decline in intracranial compliance (a “tighter fit”), increased altitude may be related to a reduction in concussion rates in high school athletes. Study Design: Cohort study; Level of evidence, 3. Methods: Data on concussions and athlete exposures (AEs) between 2005-2006 and 2011-2012 were obtained from a large national sample of high schools (National High School Sports-Related Injury Surveillance System [High School RIO]) and were used to calculate total, competition, and practice concussion rates for aggregated sports and for football only. Results: Altitude of participating schools ranged from 7 to 6903 ft (median, 600 ft), and a total of 5936 concussions occurred in 20,618,915 exposures (2.88 per 10,000 AEs). When concussion rates were dichotomized by altitude using the median, elevated altitude was associated with a reduction in concussion rates overall (rate ratio [RR], 1.31; P < .001), in competition (RR, 1.31; P < .001), and in practice (RR, 1.29; P < .001). Specifically, high school sports played at higher altitude demonstrated a 31% reduction (95% confidence interval [CI], 25%-38%) in the incidence of total reported concussions. Likewise, concussion rates at increased altitude were reduced 30% for overall exposures, 27% for competition exposures, and 28% for practice exposures in football players (P < .001). Conclusion: The results of this epidemiological investigation indicate increased physiological responses to altitude may be associated with a reduction in sports

  20. High Altitude Medical Problems

    PubMed Central

    Hultgren, Herbert N.

    1979-01-01

    Increased travel to high altitude areas by mountaineers and nonclimbing tourists has emphasized the clinical problems associated with rapid ascent. Acute mountain sickness affects most sojourners at elevations above 10,000 feet. Symptoms are usually worse on the second or third day after arrival. Gradual ascent, spending one to three days at an intermediate altitude, and the use of acetazolamide (Diamox) will prevent or ameliorate symptoms in most instances. Serious and potentially fatal problems, such as high altitude pulmonary edema or cerebral edema, occur in approximately 0.5 percent to 1.0 percent of visitors to elevations above 10,000 feet—especially with heavy physical exertion on arrival, such as climbing or skiing. Early recognition, high flow oxygen therapy and prompt descent are crucially important in management. Our knowledge of the causes of these and other high altitude problems, such as retinal hemorrhage, systemic edema and pulmonary hypertension, is still incomplete. Even less is known of the effect of high altitudes on medical conditions common at sea level or on the action of commonly used drugs. ImagesFigure 2. PMID:483805

  1. How We Make Energy Work: Grades 4, 5, 6 Science.

    ERIC Educational Resources Information Center

    National Science Teachers Association, Washington, DC.

    This packet of units is designed to focus on the technological aspects of energy. Four units are presented, with from 1-4 lessons included in each unit. Units include: (1) basic concepts and applications of energy; (2) steps and processes of energy production and transmission; (3) fuel acquisition; and (4) energy futures and application of…

  2. Preterm birth risk at high altitude in Peru

    PubMed Central

    Levine, Lisa D.; Gonzales, Gustavo F.; Tapia, Vilma L.; Gasco, Manuel; Sammel, Mary D.; Srinivas, Sindhu K.; Ludmir, Jack

    2014-01-01

    Objective High altitude has been implicated in a variety of adverse pregnancy outcomes including preeclampsia and stillbirth. Smaller studies show conflicting data on the association between high altitude and preterm birth (PTB). The objective of this study was to assess the association between altitude and PTB. Study Design A retrospective cohort study was performed using data from the Perinatal Information System which includes deliveries from 43 hospitals in Peru from 2000–2010. Altitude was classified into: low (0–1999m), moderate (2000–2900m), and high (3000–4340m). The primary outcome was PTB (delivery <37 weeks). Secondary outcomes were cesarean delivery and small for gestational age (SGA). Deliveries <23 weeks are not included in the database. Chi-square analyses were performed to compare categorical variables and logistic regression was used to calculate odds ratios and control for confounders. Clustering by hospital was accounted for using generalized estimating equations. Results 550,166 women were included (68% low, 15% moderate, 17% high altitude). The overall PTB rate was 5.9% with no difference in PTB rate among the 3 altitudes (5.6, 6.2, 6.8%, p=0.13). There was a significant difference in cesarean rates (28.0, 26.6, 20.6%, p<0.001) with a 34% decreased risk at high vs. low altitude adjusted for confounders (aOR 0.66 [0.51–0.85]). There was a difference in SGA (3.3, 3.6, 5.0%, p=0.02) with a 51% increased risk at high vs. low altitude adjusted for confounders (aOR 1.49 [1.14–1.93]). Conclusions High altitude is not associated with PTB. At high altitude, the cesarean rate was reduced and SGA rate was increased. PMID:25173185

  3. Ear - blocked at high altitudes

    MedlinePlus

    ... ears; Flying and blocked ears; Eustachian tube dysfunction - high altitude ... the middle ear and the back of the nose and upper throat. ... down from high altitudes. Chewing gum the entire time you are ...

  4. Solar altitude frequency tables

    NASA Astrophysics Data System (ADS)

    McDowell, R. S.

    1983-02-01

    A table is presented that gives the total number of hours in the year during which the sun's altitude exceeds a given value h, for h = 0-88 deg in 2 deg increments and for latitudes from the Equator to the North Pole in 2 deg increments. The table also gives corrections to these figures for the effect of atmospheric refraction and the total hours of daylight at each latitude.

  5. Security: Step by Step

    ERIC Educational Resources Information Center

    Svetcov, Eric

    2005-01-01

    This article provides a list of the essential steps to keeping a school's or district's network safe and sound. It describes how to establish a security architecture and approach that will continually evolve as the threat environment changes over time. The article discusses the methodology for implementing this approach and then discusses the…

  6. Satellite altitude determination uncertainties

    NASA Technical Reports Server (NTRS)

    Siry, J. W.

    1972-01-01

    Satellite altitude determination uncertainties will be discussed from the standpoint of the GEOS-C satellite, from the longer range viewpoint afforded by the Geopause concept. Data are focused on methods for short-arc tracking which are essentially geometric in nature. One uses combinations of lasers and collocated cameras. The other method relies only on lasers, using three or more to obtain the position fix. Two typical locales are looked at, the Caribbean area, and a region associated with tracking sites at Goddard, Bermuda and Canada which encompasses a portion of the Gulf Stream in which meanders develop.

  7. The fifth spectrum of platinum (Pt V): Analysis of the (5d6 + 5d5 6 s) - 5d5 6 p transition array

    NASA Astrophysics Data System (ADS)

    Azarov, Vladimir I.; Gayasov, Robert R.

    2016-03-01

    The spectrum of platinum was observed in the 300-2100 Å wavelength region. The (5d6 + 5d5 6 s) - 5d5 6 p transition array of four times ionized platinum, Pt V, has been investigated and 1659 spectral lines have been classified in the region of 460-1730 Å. The analysis has led to the determination of the 5d6, 5d5 6 s and 5d5 6 p configurations. Thirty two of 34 theoretically possible 5d6 levels, 45 of 74 possible 5d5 6 s levels and 181 of 214 possible 5d5 6 p levels have been established. The orthogonal operators technique was used to calculate the level structure and transition probabilities. The energy parameters have been determined by the least squares fit to the observed levels. Calculated transition probability and energy values, as well as LS-compositions obtained from the fitted parameters are presented.

  8. Risk of impaired coagulation in warfarin patients ascending to altitude (>2400 m).

    PubMed

    Van Patot, Martha C Tissot; Hill, Ashley E; Dingmann, Colleen; Gaul, Lawrence; Fralick, Kelly; Christians, Uwe; Honigman, Benjamin; Salman, M D

    2006-01-01

    Approximately 476,000 people on warfarin therapy visit a resort at altitude (>2400 m) annually in Colorado. Clinicians practicing at altitude have expressed concern that ascent to altitude adversely affects coagulation in patients taking warfarin in both high altitude residents and visitors. We sought to determine the effect of ascent to and descent from altitude on coagulation in warfarin patients, as assessed by the international normalized ratio (INR). A retrospective medical chart review was conducted on all warfarin patients treated between August 1998 and October 2003 at a cardiology clinic in which travel to and from altitude was documented in association with each INR measurement in high altitude residents. Of the 1139 INR measurements in 49 patients, 143 were associated with changes in altitude (in 32 of 49 patients). The odds of an INR measurement being below the prescribed range were 2.7 times (95% CI: 1.2-5.8) higher among warfarin patients with recent ascent to altitude, 2.1 times (95% CI: 1.4-3.2) higher among warfarin patients with atrial fibrillation, and 5.6 (95% CI: 2.3-13.7) times higher among warfarin patients with both atrial fibrillation and recent ascent to altitude. Increasing altitude is a risk factor for subtherapeutic INR in warfarin patients and this risk is doubled in atrial fibrillation patients. PMID:16544965

  9. Infectious Diseases at High Altitude.

    PubMed

    Basnyat, Buddha; Starling, Jennifer M

    2015-08-01

    Travel to elevations above 2,500 m is an increasingly common activity undertaken by a diverse population of individuals. These may be trekkers, climbers, miners in high-altitude sites in South America, and more recently, soldiers deployed for high-altitude duty in remote areas of the world. What is also being increasingly recognized is the plight of the millions of pilgrims, many with comorbidities, who annually ascend to high-altitude sacred areas. There are also 400 million people who reside permanently in high mountain ranges, which cover one-fifth of the Earth's surface. Many of these high-altitude areas are in developing countries, for example, the Himalayan range in South Asia. Although high-altitude areas may not harbor any specific infectious disease agents, it is important to know about the pathogens encountered in the mountains to be better able to help both the ill sojourner and the native high-altitude dweller. Often the same pathogens prevalent in the surrounding lowlands are found at high altitude, but various factors such as immunomodulation, hypoxia, poor physiological adaptation, and harsh environmental stressors at high altitude may enhance susceptibility to these pathogens. Against this background, various gastrointestinal, respiratory, dermatological, neurological, and other infections encountered at high altitude are discussed. PMID:26350326

  10. High Altitude Emissions

    NASA Technical Reports Server (NTRS)

    Bulzan, Dan

    2007-01-01

    An overview of emissions related research being conducted as part of the Fundamental Aeronautics Supersonics Project is presented. The overview includes project objectives, milestones, and descriptions of major research areas. The overview also includes information on the emissions research being conducted under NASA Research Announcements. Technical challenges include: 1) Environmental impact of supersonic cruise emissions is greater due to higher flight altitudes which makes emissions reduction increasingly important. 2) Accurate prediction tools to enable combustor designs that reduce emissions at supersonic cruise are needed as well as intelligent systems to minimize emissions. 3) Combustor operating conditions at supersonic cruise are different than at subsonic cruise since inlet fuel and air temperatures are considerably increased.

  11. Satellite altitude determination uncertainties

    NASA Technical Reports Server (NTRS)

    Siry, J. W.

    1971-01-01

    Satellite altitude determination uncertainties are discussed from the standpoint of the GEOS-C satellite. GEOS-C will be tracked by a number of the conventional satellite tracking systems, as well as by two advanced systems; a satellite-to-satellite tracking system and lasers capable of decimeter accuracies which are being developed in connection with the Goddard Earth and Ocean Dynamics Applications program. The discussion is organized in terms of a specific type of GEOS-C orbit which would satisfy a number of scientific objectives including the study of the gravitational field by means of both the altimeter and the satellite-to-satellite tracking system, studies of tides, and the Gulf Stream meanders.

  12. Altitude release mechanism

    DOEpatents

    Kulhanek, Frank C.

    1977-01-01

    An altitude release mechanism for releasing a radiosonde or other measuring instrument from a balloon carrying it up into the atmosphere includes a bottle partially filled with water, a tube sealed into the bottle having one end submerged in the water in the bottle and the free end extending above the top of the bottle and a strip of water-disintegrable paper held within the free end of the tube linking the balloon to the remainder of the package. As the balloon ascends, the lowered atmospheric air pressure causes the air in the bottle to expand, forcing the water in the bottle up the tubing to wet and disintegrate the paper, releasing the package from the balloon.

  13. Long-Term Exposure to High Altitude Affects Response Inhibition in the Conflict-monitoring Stage

    PubMed Central

    Ma, Hailin; Wang, Yan; Wu, Jianhui; Luo, Ping; Han, Buxin

    2015-01-01

    To investigate the effects of high-altitude exposure on response inhibition, event-related potential (ERP) components N2 and P3 were measured in Go/NoGo task. The participants included an ‘immigrant’ high-altitude group (who had lived at high altitude for three years but born at low altitude) and a low-altitude group (living in low altitude only). Although the behavioural data showed no significant differences between the two groups, a delayed latency of NoGo-N2 was found in the high-altitude group compared to the low-altitude group. Moreover, larger N2 and smaller P3 amplitudes were found in the high-altitude group compared to the low-altitude group, for both the Go and NoGo conditions. These findings suggest that high-altitude exposure affects response inhibition with regard to processing speed during the conflict monitoring stage. In addition, high altitude generally increases the neural activity in the matching step of information processing and attentional resources. These results may provide some insights into the neurocognitive basis of the effects on high-altitude exposure on response inhibition. PMID:26324166

  14. 7 CFR 5.6 - Revision of the parity price of a commodity.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false Revision of the parity price of a commodity. 5.6 Section 5.6 Agriculture Office of the Secretary of Agriculture DETERMINATION OF PARITY PRICES § 5.6 Revision of the parity price of a commodity. (a) Initiation of hearings. The “modernized” parity...

  15. 7 CFR 5.6 - Revision of the parity price of a commodity.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false Revision of the parity price of a commodity. 5.6 Section 5.6 Agriculture Office of the Secretary of Agriculture DETERMINATION OF PARITY PRICES § 5.6 Revision of the parity price of a commodity. (a) Initiation of hearings. The “modernized” parity...

  16. 7 CFR 5.6 - Revision of the parity price of a commodity.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 1 2014-01-01 2014-01-01 false Revision of the parity price of a commodity. 5.6 Section 5.6 Agriculture Office of the Secretary of Agriculture DETERMINATION OF PARITY PRICES § 5.6 Revision of the parity price of a commodity. (a) Initiation of hearings. The “modernized” parity...

  17. 7 CFR 5.6 - Revision of the parity price of a commodity.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Revision of the parity price of a commodity. 5.6 Section 5.6 Agriculture Office of the Secretary of Agriculture DETERMINATION OF PARITY PRICES § 5.6 Revision of the parity price of a commodity. (a) Initiation of hearings. The “modernized” parity...

  18. 7 CFR 5.6 - Revision of the parity price of a commodity.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 1 2012-01-01 2012-01-01 false Revision of the parity price of a commodity. 5.6 Section 5.6 Agriculture Office of the Secretary of Agriculture DETERMINATION OF PARITY PRICES § 5.6 Revision of the parity price of a commodity. (a) Initiation of hearings. The “modernized” parity...

  19. Cardiovascular physiology at high altitude.

    PubMed

    Hooper, T; Mellor, A

    2011-03-01

    The role of the cardiovascular system is to deliver oxygenated blood to the tissues and remove metabolic effluent. It is clear that this complex system will have to adapt to maintain oxygen deliver in the profound hypoxia of high altitude. The literature on the adaptation of both the systemic and pulmonary circulations to high altitude is reviewed. PMID:21465906

  20. Cardiovascular medicine at high altitude.

    PubMed

    Whayne, Thomas F

    2014-07-01

    Altitude physiology began with Paul Bert in 1878. Chronic mountain sickness (CMS) was defined by Carlos Monge in the 1940s in the Peruvian Andes as consisting of excess polycythemia. Hurtado et al performed studies in the Peruvian Andes in the 1950s to 1960s which defined acclimatization in healthy altitude natives, including polycythemia, moderate pulmonary hypertension, and low systemic blood pressure (BP). Electrocardiographic changes of right ventricular hypertrophy (RVH) were noted. Acclimatization of newcomers to altitude involves hyperventilation stimulated by hypoxia and is usually benign. Acute mountain sickness (AMS) in travelers to altitude is characterized by hypoxia-induced anorexia, dyspnea, headache, insomnia, and nausea. The extremes of AMS are high-altitude cerebral edema and high-altitude pulmonary edema. The susceptible high-altitude resident can lose their tolerance to altitude and develop CMS, also referred to as Monge disease. The CMS includes extreme polycythemia, severe RVH, excess pulmonary hypertension, low systemic BP, arterial oxygen desaturation, and hypoventilation. PMID:23892441

  1. Synthesis and study of fluorescence properties of novel pyrazolo[4‧,3‧:5,6]pyrido[2,3-d]pyrimidin-5(6H)-one derivatives

    NASA Astrophysics Data System (ADS)

    Quiroga, Jairo; Acosta, Paola; Ortiz, Alejandro; Insuasty, Braulio; Abonia, Rodrigo

    2015-10-01

    New pyrazolo[4‧,3‧:5,6]pyrido[2,3-d]pyrimidin-5(6H)-one derivatives 5 were prepared by cyclocondensation reaction between heterocyclic o-aminonitriles 3 and carboxylic acids 4 in the presence of sulfuric acid as catalyst. This procedure provides the desired compound in good yield with a simple one-step methodology. The obtained products show interesting fluorescence properties in both solution and solid state; in this way several spectra of absorption and emission were measured for selected compounds 5b, 5e, 5g and 5j, showing a broad and intense emission band around of 470 nm. In other to understand the electronic transition processes, theoretical calculations were performed at TD-DFT level, using B3LYP as functional and 6-31(d,p) as basis set, finding a good agreement with experimental measurements.

  2. Next Step for STEP

    SciTech Connect

    Wood, Claire; Bremner, Brenda

    2013-08-09

    The Siletz Tribal Energy Program (STEP), housed in the Tribe’s Planning Department, will hire a data entry coordinator to collect, enter, analyze and store all the current and future energy efficiency and renewable energy data pertaining to administrative structures the tribe owns and operates and for homes in which tribal members live. The proposed data entry coordinator will conduct an energy options analysis in collaboration with the rest of the Siletz Tribal Energy Program and Planning Department staff. An energy options analysis will result in a thorough understanding of tribal energy resources and consumption, if energy efficiency and conservation measures being implemented are having the desired effect, analysis of tribal energy loads (current and future energy consumption), and evaluation of local and commercial energy supply options. A literature search will also be conducted. In order to educate additional tribal members about renewable energy, we will send four tribal members to be trained to install and maintain solar panels, solar hot water heaters, wind turbines and/or micro-hydro.

  3. High altitude reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Yazdo, Renee Anna; Moller, David

    1990-01-01

    At the equator the ozone layer ranges from 65,000 to 130,000 plus feet, which is beyond the capabilities of the ER-2, NASA's current high altitude reconnaissance aircraft. The Universities Space Research Association, in cooperation with NASA, is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to cruise at 130,000 feet for six hours at Mach 0.7, while carrying 3,000 lbs. of payload. In addition, the aircraft must have a minimum range of 6,000 miles. In consideration of the novel nature of this project, the pilot must be able to take control in the event of unforeseen difficulties. Three aircraft configurations were determined to be the most suitable - a joined-wing, a biplane, and a twin-boom conventional airplane. The performance of each configuration was analyzed to investigate the feasibility of the project.

  4. The discovery of novel 5,6,5- and 5,5,6-tricyclic pyrrolidines as potent and selective DPP-4 inhibitors.

    PubMed

    Cox, Jason M; Chu, Hong D; Kuethe, Jeffrey T; Gao, Ying-Duo; Scapin, Giovanna; Eiermann, George; He, Huaibing; Li, Xiaohua; Lyons, Kathryn A; Metzger, Joseph; Petrov, Aleksandr; Wu, Joseph K; Xu, Shiyao; Sinha-Roy, Ranabir; Weber, Ann E; Biftu, Tesfaye

    2016-06-01

    Novel potent and selective 5,6,5- and 5,5,6-tricyclic pyrrolidine dipeptidyl peptidase IV (DPP-4) inhibitors were identified. Structure-activity relationship (SAR) efforts focused on improving the intrinsic DPP-4 inhibition potency, increasing protease selectivity, and demonstrating clean ion channel and cytochrome P450 profiles while trying to achieve a pharmacokinetic profile suitable for once weekly dosing in humans. PMID:27106708

  5. Coronary heart disease at altitude.

    PubMed Central

    Alexander, J K

    1994-01-01

    In the past, it has been assumed that some basic physiologic responses to altitude, exposure in coronary patients are comparable to those in normal young subjects. In fact there are similar changes in sympathetic activation, heart rate, and blood pressure early after ascent, with decrements in plasma volume, cardiac output, and stroke volume as acclimatization proceeds. These responses are described, and experience with coronary patients is reviewed. During the 1st 2 to 3 days at altitude, coronary patients are at greatest risk of untoward events. Gradual rather than abrupt ascent, a moderate degree of physical conditioning, early limitation of activity to a level tolerated at low altitude for somewhat less), and attention to blood pressure control all appear to have protective effects. Ascent to moderate altitude appears to entail little risk in coronary patients who are asymptomatic or have moderate exercise tolerance, provided that the above precautions are observed and that activity does not exceed levels at lower altitude. If activity is to be increased, pre-ascent treadmill exercise testing or Holter monitor data secured under conditions comparable to those anticipated at altitude may provide reasonable guidelines. For coronary patients previously evaluated and known to be in a high-risk category, indications for ascent should be examined more critically, and precautionary measures should be more rigorous. Advice for patients with known coronary disease who may desire to trek at very high altitude must involve individual evaluation, and guidelines remain elusive. PMID:7888800

  6. Lung Disease at High Altitude

    PubMed Central

    Stream, JO; Luks, AM; Grissom, CK

    2016-01-01

    Large numbers of people travel to high altitudes, entering an environment of hypobaric hypoxia. Exposure to low oxygen tension leads to a series of important physiologic responses that allow individuals to tolerate these hypoxic conditions. However, in some cases hypoxia triggers maladaptive responses that lead to various forms of acute and chronic high altitude illness, such as high-altitude pulmonary edema or chronic mountain sickness. Because the respiratory system plays a critical role in these adaptive and maladaptive responses, patients with underlying lung disease may be at increased risk for complications in this environment and warrant careful evaluation before any planned sojourn to higher altitudes. In this review, we describe respiratory disorders that occur with both acute and chronic exposures to high altitudes. These disorders may occur in any individual who ascends to high altitude, regardless of his/her baseline pulmonary status. We then consider the safety of high-altitude travel in patients with various forms of underlying lung disease. The available data regarding how these patients fare in hypoxic conditions are reviewed, and recommendations are provided for management prior to and during the planned sojourn. PMID:20477353

  7. All-cis 1,2,3,4,5,6-hexafluorocyclohexane is a facially polarized cyclohexane

    NASA Astrophysics Data System (ADS)

    Keddie, Neil S.; Slawin, Alexandra M. Z.; Lebl, Tomas; Philp, Douglas; O'Hagan, David

    2015-06-01

    The highest-energy stereoisomer of 1,2,3,4,5,6-hexafluorocyclohexane, in which all of the fluorines are ‘up’, is prepared in a 12-step protocol. The molecule adopts a classic chair conformation with alternate C-F bonds aligned triaxially, clustering three highly electronegative fluorine atoms in close proximity. This generates a cyclohexane with a high molecular dipole (μ = 6.2 D), unusual in an otherwise aliphatic compound. X-ray analysis indicates that the intramolecular Fax···Fax distances (˜2.77 Å) are longer than the vicinal Fax···Feq­ distances (˜2.73 Å) suggesting a tension stabilizing the chair conformation. In the solid state the molecules pack in an orientation consistent with electrostatic ordering. Our synthesis of this highest-energy isomer demonstrates the properties that accompany the placement of axial fluorines on a cyclohexane and the unusual property of a facially polarized ring in organic chemistry. Derivatives have potential as new motifs for the design of functional organic molecules or for applications in supramolecular chemistry design.

  8. A3 Altitude Test Facility

    NASA Technical Reports Server (NTRS)

    Dulreix, Lionel J.

    2009-01-01

    This slide presentation shows drawings, diagrams and photographs of the A3 Altitude Test Facility. It includes a review of the A3 Facility requirements, and drawings of the various sections of the facility including Engine Deck and Superstructure, Test Cell and Thrust Takeout, Structure and Altitude Support Systems, Chemical Steam generators, and the subscale diffuser. There are also pictures of the construction site, and the facility under construction. A Diagram of the A3 Steam system schematic is also shown

  9. The Effects of the Parenting Styles on Social Skills of Children Aged 5-6

    ERIC Educational Resources Information Center

    Kol, Suat

    2016-01-01

    The purpose of this study is to determine the effects of the parenting styles on social skills of children aged 5-6. The problem sentence of the research is; Do the parenting styles' have any effects on social skills of children aged 5-6?. The sub-problems of the research are in the form as; Does the social skills of children aged 5-6 differs from…

  10. Analysis of Pulsed Airborne Lidar Measurements of Atmospheric CO2 Column Absorption from 3-13 km Altitudes

    NASA Technical Reports Server (NTRS)

    Abshire, James B.; Weaver, Clark J.; Riris, Haris; Mao, Jianping; Sun, Xiaoli; Allan, Graham R.; Hasselbrack, William; Browell, Edward V.

    2011-01-01

    through thin clouds. The Oklahoma and east coast flights were coordinated with a LaRC/ITT CO2 lidar on the LaRC UC-12 aircraft, and in-situ measurements were made using its CO2 sensor and radiosondes. We have conducted an analysis of the ranging and IPDA lidar measurements from these four flights. Most flights had 5-6 altitude steps with 200-300 seconds of recorded measurements per step. We used a cross-correlation approach to process the laser echo records. This was used to estimate the range to the scattering surface, to define the edges of the laser pulses and to determine echo pulse energy at each wavelength. We used a minimum mean square approach to fit an instrument response function and to solve for the best-fit CO2 absorption line shape. We then calculated the differential optical depth (DOD) of the fitted CO2 line. We computed its statistics at the various altitude steps, and compare them to the DODs calculated from spectroscopy based on HITRAN 2008 and the column conditions calculated from the airborne in-situ readings. The results show the lidar and in-situ measurements have very similar DOD change with altitude and greater than 10 segments per flight where the scatter in the lidar measurements are less than or equal to 1ppm. We also present the results from subsequent CO2 column absorption measurements, which were made with stronger detected signals during three flights on the NASA DC-8 over the southwestern US in during July 2010.

  11. Renal failure in high altitude: renal functions, renal pathology and bone mineralization in rats with ablation nephropathy at 1200 m altitude.

    PubMed

    Soylu, Alper; Kavukçu, Salih; Yilmaz, Osman; Astarcioğlu, Hüseyin; Ozkal, Sermin; Türkmen, Mehmet; Sarioğlu, Sülen

    2007-01-01

    The effect of altitude on renal failure and bone mineralization is not well known. This topic is studied in a 5/6 nephrectomy rat model. After hemoglobin, creatinine clearance and proteinuria were determined in 28 Wistar rats. Two 5/6 nephrectomy (Nx1-Nx2, n=7 each) and two sham (Sh1-Sh2, n=7 each) groups were formed. The Nx1-Sh1 and Nx2-Sh2 groups were kept at sea level and at 1200 m altitude, respectively. The same analyses were performed after 3 months just before sacrifices in order to harvest kidneys and femurs for histopathologic examination. Hemoglobin, creatinine clearance, and proteinuria were similar in all groups at the onset. Final hemoglobin was higher in Nx2-Sh2, but only Sh2 vs. Sh1 was significant (p=0.001). Creatinine clearance decreased (p=0.001 for Nx1) and proteinuria increased (p=0.002 for Nx1 and p=0.005 for Nx2) after 5/6 nephrectomy, but Nx1 vs. Nx2 was similar. Histopathological changes in the remnant kidneys were prominent, but Nx1 vs. Nx2 was not different. Although the relative osteoid volume increased in Nx groups, only Nx1 vs. Sh1 was different (p=0.006). In conclusion, exposure to 1200 m altitude, compared to the sea level, preserved the creatinine clearance better in 5/6 nephrectomized rats. No change was observed in proteinuria, renal histopathology, and bone mineralization. PMID:17904299

  12. 43 CFR 3585.5-6 - Publication and posting of notice.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Publication and posting of notice. 3585.5-6 Section 3585.5-6 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) SPECIAL LEASING AREAS...

  13. The Effect of Science Activities on Concept Acquisition of Age 5-6 Children Groups

    ERIC Educational Resources Information Center

    Dogru, Mustafa; Seker, Fatih

    2012-01-01

    Present research aims to determine the effect of science activities on concept development of preschool period age 5-6 children groups. Parallel to research objective, qualitative research pattern has been the selected method. Study group comprises of collectively 48 children from 5-6 age group attending to a private education institution in city…

  14. IMMUNOASSAY METHODS FOR MEASURING ATRAZINE AND 3,5,6-TRICHLORO-2-PYRIDINOL IN FOODS

    EPA Science Inventory

    This chapter describes the use of enzyme-linked immunosorbent assay (ELISA) methods for the analysis of two potential environmental contaminants in food sample media, atrazine and 3,5,6-trichloro-2-pyridinol (3,5,6-TCP). Two different immunoassay formats are employed: a magnetic...

  15. Synthesis and biological activity of substituted-4,5,6,7-tetrahydrothieno pyridines: a review.

    PubMed

    Sangshetti, Jaiprakash N; Zambare, Abhay S; Khan, Firoz A Kalam; Gonjari, Indrajeet; Zaheer, Zahid

    2014-01-01

    4,5,6,7-Tetrahydrothieno pyridine is an important class of heterocyclic nucleus. Various 4,5,6,7-tetrahydrothieno pyridine derivatives have been synthesized and evaluated for various biological activities in different models with desired findings. Some analogs have shown potent biological activities and may be considered as lead molecule for the development of future drugs. Number of drug molecules are available in the market and many molecules are in clinical development containing 4,5,6,7-tetrahydrothieno pyridine nucleus as an important core. This review is an attempt to organize the chemical and biological aspects of 4,5,6,7-tetrahydrothieno pyridine analogs reported in last 20 year to till date. Review mainly focuses on the important role of the core in synthesis of drug or drug intermediates giving emphasis on synthetic schemes and biological activities of the different 4,5,6,7-tetrahydrothieno pyridine analogs. PMID:25373848

  16. The TRPV5/6 calcium channels contain multiple calmodulin binding sites with differential binding properties.

    PubMed

    Kovalevskaya, Nadezda V; Bokhovchuk, Fedir M; Vuister, Geerten W

    2012-06-01

    The epithelial Ca(2+) channels TRPV5/6 (transient receptor potential vanilloid 5/6) are thoroughly regulated in order to fine-tune the amount of Ca(2+) reabsorption. Calmodulin has been shown to be involved into calcium-dependent inactivation of TRPV5/6 channels by binding directly to the distal C-terminal fragment of the channels (de Groot et al. in Mol Cell Biol 31:2845-2853, 12). Here, we investigate this binding in detail and find significant differences between TRPV5 and TRPV6. We also identify and characterize in vitro four other CaM binding fragments of TRPV5/6, which likely are also involved in TRPV5/6 channel regulation. The five CaM binding sites display diversity in binding modes, binding stoichiometries and binding affinities, which may fine-tune the response of the channels to varying Ca(2+)-concentrations. PMID:22354706

  17. Solar collector with altitude tracking

    DOEpatents

    Barak, Amitzur Z.

    1977-01-01

    A device is provided for turning a solar collector about an east-west horizontal axis so that the collector is tilted toward the sun as the EWV altitude of the sun varies each day. It includes one or more heat responsive elements and a shading means aligned so that within a range of EWV altitudes of the sun during daylight hours the shading means shades the element or elements while during the rest of the daylight hours the elements or elements are heated by the sun to assume heated, stable states. Mechanical linkage between the collector and the element is responsive to the states of the element or elements to tilt the collector in accordance with variations in the EWV altitude of the sun.

  18. Return to Activity at Altitude After High-Altitude Illness

    PubMed Central

    DeWeber, Kevin; Scorza, Keith

    2010-01-01

    Context: Sports and other activities at high altitude are popular, yet they pose the unique risk for high-altitude illness (HAI). Once those who have suffered from a HAI recover, they commonly desire or need to perform the same activity at altitude in the immediate or distant future. Evidence Acquisition: As based on key text references and peer-reviewed journal articles from a Medline search, this article reviews the pathophysiology and general treatment principles of HAI. Results: In addition to the type of HAI experienced and the current level of recovery, factors needing consideration in the return-to-play plan include physical activity requirements, flexibility of the activity schedule, and available medical equipment and facilities. Most important, adherence to prudent acclimatization protocols and gradual ascent recommendations (when above 3000 m, no more than 600-m net elevation gain per day, and 1 rest day every 1 to 2 ascent days) is powerful in its preventive value and thus strongly recommended. When these are not practical, prophylactic medications (acetazolamide, dexamethasone, salmeterol, nifedipine, or phosphodiesterase inhibitors, depending on the type of prior HAI) may be prescribed and can reduce the risk of illness. Athletes with HAI should be counseled that physical and mental performance may be adversely affected if activity at altitude continues before recovery is complete and that there is a risk of progression to a more serious HAI. Conclusion: With a thoughtful plan, most recurrent HAI in athletes can be prevented. PMID:23015950

  19. Inositol 1,3,4,5,6-Pentakisphosphate 2-Kinase from Maize: Molecular and Biochemical Characterization[OA

    PubMed Central

    Sun, Yuejin; Thompson, Mark; Lin, Gaofeng; Butler, Holly; Gao, Zhifang; Thornburgh, Scott; Yau, Kerrm; Smith, Doug A.; Shukla, Vipula K.

    2007-01-01

    Inositol 1,3,4,5,6-pentakisphosphate 2-kinase, an enzyme encoded by the gene IPK1, catalyzes the terminal step in the phytic acid biosynthetic pathway. We report here the isolation and characterization of IPK1 cDNA and genomic clones from maize (Zea mays). DNA Southern-blot analysis revealed that ZmIPK1 in the maize genome constitutes a small gene family with two members. Two nearly identical ZmIPK1 paralogs, designated as ZmIPK1A and ZmIPK1B, were identified. The transcripts of ZmIPK1A were detected in various maize tissues, including leaves, silks, immature ears, seeds at 12 d after pollination, midstage endosperm, and maturing embryos. However, the transcripts of ZmIPK1B were exclusively detected in roots. A variety of alternative splicing products of ZmIPK1A were discovered in maize leaves and seeds. These products are derived from alternative acceptor sites, alternative donor sites, and retained introns in the transcripts. Consequently, up to 50% of the ZmIPK1A transcripts in maize seeds and leaves have an interrupted open reading frame. In contrast, only one type of splicing product of ZmIPK1B was detected in roots. When expressed in Escherichia coli and subsequently purified, the ZmIPK1 enzyme catalyzes the conversion of myo-inositol 1,3,4,5,6-pentakisphosphate to phytic acid. In addition, it is also capable of catalyzing the phosphorylation of myo-inositol 1,4,6-trisphosphate, myo-inositol 1,4,5,6-tetrakisphosphate, and myo-inositol 3,4,5,6-tetrakisphosphate. Nuclear magnetic resonance spectroscopy analysis indicates that the phosphorylation product of myo-inositol 1,4,6-trisphosphate is inositol 1,2,4,6-tetrakisphosphate. Kinetic studies showed that the Km for ZmIPK1 using myo-inositol 1,3,4,5,6-pentakisphosphate as a substrate is 119 μm with a Vmax at 625 nmol/min/mg. These data describing the tissue-specific accumulation and alternative splicing of the transcripts from two nearly identical ZmIPK1 paralogs suggest that maize has a highly sophisticated

  20. Efficient alcoholysis of 5,6-dihydro-1,10-phenanthroline-5,6-epoxide with ytterbium(III) triflate and subsequent enantioselective transesterification with lipases

    PubMed Central

    Schoffers, Elke; Kohler, Lars

    2009-01-01

    New 5,6-dihydro-1,10-phenanthroline derivatives were prepared in high yield via ytterbium(III) triflate-catalyzed alcoholysis of the corresponding epoxide. Enzymatic transesterifications of racemic alkoxy alcohols afforded enantioselective separations with up to 99% ee. The lipase derived from Burkholderia cepacia (PSCI) was the most efficient, with E-values of up to 200. The steric effect of substituents in the 6-position on reaction time and enantioselectivities was assessed. PMID:20160975

  1. Hydrogen peroxide generation associated with the oxidations of the eumelanin precursors 5,6-dihydroxyindole and 5,6-dihydroxyindole-2-carboxylic acid.

    PubMed

    Nappi, A J; Vass, E

    1996-10-01

    The ability of iron chelates to promote hydroxyl radical (.OH) formation from hydrogen peroxide (H2O2) via Fenton chemistry was exploited to detect H2O2 produced during the oxidations of the eumelanin precursors 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA). H2O2 generation during the autooxidations of DHI and DHICA was confirmed on the basis of the electrochemical detection of three hydroxylation products of salicylate [2,3 and 2,5-dihydroxybenzoic acid (DHBA) and catechol], which was used as an .OH indicator. The oxidations of both 5,6-dihydroxyindoles were augmented by tyrosinase and peroxidase without the addition of H2O2. The partial inhibitions by catalase of the auto-oxidations and tyrosinase- and peroxidase-mediated oxidations of DHI and DHICA provide additional evidence of an endogenous origin of H2O2 during the final stages of eumelanogenesis. The mechanism proposed for the formation of H2O2 involves the semiquinones of DHI and DHICA in the univalent transfer of electrons to molecular oxygen. The observations described in this study support previous reports suggesting that factors modulating the levels of H2O2 in melanocytes and melanoma cells play critical roles in directing the course of melanogenesis and influencing the potential cytotoxicity of the biosynthetic pathways. PMID:8908594

  2. Lidar Altitude Data Read Routine

    Atmospheric Science Data Center

    2013-03-19

    ... Profile products. It is written in Interactive Data Language (IDL) and uses HDF routine calls to read the altitude data which are ... Data Read routine  (1.5 KB) Interactive Data Language (IDL) is available from  Exelis Visual Information Solutions . ...

  3. Development of Aptitude at Altitude

    ERIC Educational Resources Information Center

    Hogan, Alexandra M.; Virues-Ortega, Javier; Botti, Ana Baya; Bucks, Romola; Holloway, John W.; Rose-Zerilli, Matthew J.; Palmer, Lyle J.; Webster, Rebecca J.; Baldeweg, Torsten; Kirkham, Fenella J.

    2010-01-01

    Millions of people currently live at altitudes in excess of 2500 metres, where oxygen supply is limited, but very little is known about the development of brain and behavioural function under such hypoxic conditions. We describe the physiological, cognitive and behavioural profile of a large cohort of infants (6-12 months), children (6-10 years)…

  4. Altitude Compensating Nozzle Concepts Evaluation

    NASA Technical Reports Server (NTRS)

    Soni, Bharat

    2000-01-01

    This report contains the summary of work accomplished during summer of 2000 by Mr. Chad Hammons, undergraduate senior student, Mississippi State University/ERC in support of NASA/MSFC mission pertinent to Altitude compensating nozzle concepts evaluations. In particular, the development of automatic grid generator applicable in conducting sensitivity analysis involving Aerospike engine is described.

  5. Synthesis of 2-arylamino substituted 5,6-dihydropyrido[2,3-d]pyrimidine-7(8H)-ones from arylguanidines.

    PubMed

    Galve, Iñaki; Puig de la Bellacasa, Raimon; Sánchez-García, David; Batllori, Xavier; Teixidó, Jordi; Borrell, José I

    2012-11-01

    A practical protocol was developed for the synthesis of 2-arylamino substituted 4-amino-5,6-dihydropyrido[2,3-d]pyrimidin-7(8H)-ones from α,β-unsaturated esters, malononitrile, and an aryl substituted guanidine via the corresponding 3-aryl-3,4,5,6- tetrahydropyrido[2,3-d]pyrimidin-7(8H)-ones. Such compounds are formed upon treatment of 2-methoxy-6-oxo-1,4,5,6-tetrahydropyridine-3-carbonitriles with an aryl substituted guanidine in 1,4-dioxane and are converted to the desired 4-aminopyridopyrimidines with NaOMe/MeOH through a Dimroth rearrangement. The overall yields of this three-step protocol are, generally speaking, higher than the multicomponent reaction, previously developed by our group, between an α,β-unsaturated ester, malononitrile, and an aryl substituted guanidine. PMID:23054532

  6. PHOEBE - step by step manual

    NASA Astrophysics Data System (ADS)

    Zasche, P.

    2016-03-01

    An easy step-by-step manual of PHOEBE is presented. It should serve as a starting point for the first time users of PHOEBE analyzing the eclipsing binary light curve. It is demonstrated on one particular detached system also with the downloadable data and the whole procedure is described easily till the final trustworthy fit is being reached.

  7. Step Pultrusion

    NASA Astrophysics Data System (ADS)

    Langella, A.; Carbone, R.; Durante, M.

    2012-12-01

    The pultrusion process is an efficient technology for the production of composite material profiles. Thanks to this positive feature, several studies have been carried out, either to expand the range of products made using the pultrusion technology, or improve its already high production rate. This study presents a process derived from the traditional pultrusion technology named "Step Pultrusion Process Technology" (SPPT). Using the step pultrusion process, the final section of the composite profiles is obtainable by means of a progressive cross section increasing through several resin cure stations. This progressive increasing of the composite cross section means that a higher degree of cure level can be attained at the die exit point of the last die. Mechanical test results of the manufactured pultruded samples have been used to compare both the traditional and the step pultrusion processes. Finally, there is a discussion on ways to improve the new step pultrusion process even further.

  8. Sleep and Breathing at High Altitude.

    PubMed

    Wickramasinghe, Himanshu; Anholm, James D.

    1999-01-01

    Sleep at high altitude is characterized by poor subjective quality, increased awakenings, frequent brief arousals, marked nocturnal hypoxemia, and periodic breathing. A change in sleep architecture with an increase in light sleep and decreasing slow-wave and REM sleep have been demonstrated. Periodic breathing with central apnea is almost universally seen amongst sojourners to high altitude, although it is far less common in long-standing high altitude dwellers. Hypobaric hypoxia in concert with periodic breathing appears to be the principal cause of sleep disruption at altitude. Increased sleep fragmentation accounts for the poor sleep quality and may account for some of the worsened daytime performance at high altitude. Hypoxic sleep disruption contributes to the symptoms of acute mountain sickness. Hypoxemia at high altitude is most severe during sleep. Acetazolamide improves sleep, AMS symptoms, and hypoxemia at high altitude. Low doses of a short acting benzodiazepine (temazepam) may also be useful in improving sleep in high altitude. PMID:11898114

  9. High Altitude Cooking and Food Safety

    MedlinePlus

    ... Where to Place the Food Thermometer Recommended Internal Temperatures Is egg cookery affected at high altitudes? Is ... atmospheric pressure — affects both the time and the temperature of most everything that's cooked. Where the altitude ...

  10. Altitude, Acute Mountain Sickness and Headache

    MedlinePlus

    ... Mountain Sickness, and Headache Print Email Altitude, Acute Mountain Sickness, and Headache ACHE Newsletter Sign up for ... entering your e-mail address below. Altitude, Acute Mountain Sickness, and Headache David W. Dodick, MD, FAHS, ...

  11. High Altitude Ozone Research Balloon

    NASA Technical Reports Server (NTRS)

    Cauthen, Timothy A.; Daniel, Leslie A.; Herrick, Sally C.; Rock, Stacey G.; Varias, Michael A.

    1990-01-01

    In order to create a mission model of the high altitude ozone research balloon (HAORB) several options for flight preparation, altitude control, flight termination, and payload recovery were considered. After the optimal launch date and location for two separate HAORB flights were calculated, a method for reducing the heat transfer from solar and infrared radiation was designed and analytically tested. This provided the most important advantage of the HAORB over conventional balloons, i.e., its improved flight duration. Comparisons of different parachute configurations were made, and a design best suited for the HAORB's needs was determined to provide for payload recovery after flight termination. In an effort to avoid possible payload damage, a landing system was also developed.

  12. Altitude characteristics of selected air quality analyzers

    NASA Technical Reports Server (NTRS)

    White, J. H.; Strong, R.; Tommerdahl, J. B.

    1979-01-01

    The effects of altitude (pressure) on the operation and sensitivity of various air quality analyzers frequently flown on aircraft were analyzed. Two ozone analyzers were studied at altitudes from 600 to 7500 m and a nitrogen oxides chemiluminescence detector and a sulfur dioxide flame photometric detector were studied at altitudes from 600 to 3000 m. Calibration curves for altitude corrections to the sensitivity of the instruments are presented along with discussion of observed instrument behavior.

  13. Low altitude plume impingement handbook

    NASA Technical Reports Server (NTRS)

    Smith, Sheldon D.

    1991-01-01

    Plume Impingement modeling is required whenever an object immersed in a rocket exhaust plume must survive or remain undamaged within specified limits, due to thermal and pressure environments induced by the plume. At high altitudes inviscid plume models, Monte Carlo techniques along with the Plume Impingement Program can be used to predict reasonably accurate environments since there are usually no strong flowfield/body interactions or atmospheric effects. However, at low altitudes there is plume-atmospheric mixing and potential large flowfield perturbations due to plume-structure interaction. If the impinged surface is large relative to the flowfield and the flowfield is supersonic, the shock near the surface can stand off the surface several exit radii. This results in an effective total pressure that is higher than that which exists in the free plume at the surface. Additionally, in two phase plumes, there can be strong particle-gas interaction in the flowfield immediately ahead of the surface. To date there have been three levels of sophistication that have been used for low altitude plume induced environment predictions. Level 1 calculations rely on empirical characterizations of the flowfield and relatively simple impingement modeling. An example of this technique is described by Piesik. A Level 2 approach consists of characterizing the viscous plume using the SPF/2 code or RAMP2/LAMP and using the Plume Impingement Program to predict the environments. A Level 3 analysis would consist of using a Navier-Stokes code such as the FDNS code to model the flowfield and structure during a single calculation. To date, Level 1 and Level 2 type analyses have been primarily used to perform environment calculations. The recent advances in CFD modeling and computer resources allow Level 2 type analysis to be used for final design studies. Following some background on low altitude impingement, Level 1, 2, and 3 type analysis will be described.

  14. Hepatitis B Virus X Protein Promotes Degradation of SMC5/6 to Enhance HBV Replication.

    PubMed

    Murphy, Christopher M; Xu, Yanping; Li, Feng; Nio, Kouki; Reszka-Blanco, Natalia; Li, Xiaodong; Wu, Yaxu; Yu, Yanbao; Xiong, Yue; Su, Lishan

    2016-09-13

    The hepatitis B virus (HBV) regulatory protein X (HBx) activates gene expression from the HBV covalently closed circular DNA (cccDNA) genome. Interaction of HBx with the DDB1-CUL4-ROC1 (CRL4) E3 ligase is critical for this function. Using substrate-trapping proteomics, we identified the structural maintenance of chromosomes (SMC) complex proteins SMC5 and SMC6 as CRL4(HBx) substrates. HBx expression and HBV infection degraded the SMC5/6 complex in human hepatocytes in vitro and in humanized mice in vivo. HBx targets SMC5/6 for ubiquitylation by the CRL4(HBx) E3 ligase and subsequent degradation by the proteasome. Using a minicircle HBV (mcHBV) reporter system with HBx-dependent activity, we demonstrate that SMC5/6 knockdown, or inhibition with a dominant-negative SMC6, enhance HBx null mcHBV-Gluc gene expression. Furthermore, SMC5/6 knockdown rescued HBx-deficient HBV replication in human hepatocytes. These results indicate that a primary function of HBx is to degrade SMC5/6, which restricts HBV replication by inhibiting HBV gene expression. PMID:27626656

  15. Two 6-substituted 5,6-dihydro-alpha-pyrones from Ravensara anisata.

    PubMed

    Andrianaivoravelona, J O; Sahpaz, S; Terreaux, C; Hostettmann, K; Stoeckli-Evans, H; Rasolondramanitra, J

    1999-09-01

    The leaves and bark dichloromethane extracts of Ravensara anisata showed antifungal activity against the yeast Candida albicans and the phytopathogenic fungus Cladosporium cucumerinum in bioautographic TLC assays. Activity-guided fractionation afforded two new alpha-pyrones: 6R*-(4R*-acetoxy-2S*-hydroxy- 8-phenyloctyl)-5,6-dihydro-2-H-pyran-2-one and 6R*-(2S*-acetoxy-4R*- hydroxy-8-phenyloctyl)-5,6-dihydro-2-H-pyran-2-one. Their structures have been established by NMR spectroscopy, chemical methods and X-ray crystallographic analysis. The antifungal activity against C. albicans and C. cucumerinum was determined for both compounds. PMID:10513401

  16. Facile synthesis of 4,5,6a,7-tetrahydrodibenzo[de,g]chromene heterocycles and their transformation to phenanthrene alkaloids

    PubMed Central

    Kapadia, Nirav; Harding, Wayne

    2013-01-01

    Oxa-Pictet-Spengler cyclization and microwave-assisted C-H arylation have been implemented as key steps in the synthesis of new isochroman heterocycles containing a 4,5,6a,7-tetrahydrodibenzo[de,g]chromene motif. These isochromans may be easily transformed to phenanthrene alkaloids via acidic cleavage of the isochroman ring and standard synthetic manipulations thereafter. The route described is attractive in that it provides access to two biologically interesting scaffolds in simple and high yielding synthetic steps. PMID:24187388

  17. Analysis of the Rotational Spectra of 2,3,4,5,6-PENTAFLUOROTOLUENE and 1-CHLORO-2,3,4,5,6-PENTAFLUOROBENZENE

    NASA Astrophysics Data System (ADS)

    Osthoff, Ashley A.; Peebles, Rebecca A.; Peebles, Sean A.; Grubbs, Garry S. Grubbs, II; Cooke, Stephen A.; Pate, Brooks H.; Neill, Justin L.; Muckle, Matt T.

    2009-06-01

    The microwave spectra of two substituted pentafluorobenzenes have been obtained. 2,3,4,5,6-Pentafluorotoluene was measured using the FTMW spectrometer at Eastern Illinois University and the chirped-pulse FTMW spectrometer at University of North Texas. The heavy atom structure has been obtained from the assigned ^{13}C transitions and is in reasonable agreement with ab initio calculations at the MP2/6-311++G(2d, 2p) level. The ground state rotational constants are A = 1036.61253(10) MHz, B = 1030.94126(10) MHz, and C = 516.92062(9) MHz, and the single dipole moment component is μ_b = 1.98(17) D. Very small splittings for many of the assigned transitions and multiple, as yet unassigned, lines were presumably due to excited torsional states of the methyl group. In a related study, the microwave spectrum of 1-chloro-2,3,4,5,6-pentafluorobenzene was obtained for both the ^{35}Cl and the ^{37}Cl isotopologues using the chirped-pulse microwave spectrometer at University of Virginia. The preliminary ground state rotational constants for this compound are A = 1028.5403(14) MHz, B = 751.8198(3) MHz and C = 434.3533(4) MHz for ^{35}Cl and A = 1028.5435(7) MHz, B = 734.4786(2) MHz and C = 428.5082(2) MHz for ^{37}Cl. Initial fits of the nuclear quadrupole coupling constants give χ_{aa} = -79.512(15) MHz, χ_{bb} = 43.593(8) MHz, χ_{cc} = 35.92(2) MHz for the ^{35}Cl species and χ_{aa} = -62.68(2) MHz, χ_{bb} = 34.38(4) MHz, χ_{cc} = 28.29(17) MHz for the ^{37}Cl species. These results will be compared with pentafluorotoluene to observe the effects on the structure of the benzene ring when substituting a chlorine atom for a methyl group.

  18. The structure and properties of 5,6-dinitro-1H-benzotriazole

    NASA Astrophysics Data System (ADS)

    Santa María, Dolores; Claramunt, Rosa M.; Torralba, M. Carmen; Torres, M. Rosario; Alkorta, Ibon; Elguero, José

    2016-06-01

    5,6-Dinitro-1H-benzotriazole crystallizes in the monoclinic system, space group P21/c. The asymmetric unit contains the planar 1H-tautomer together with a water molecule of crystallization. Each water molecule is hydrogen bonded to three adjacent 5,6-dinitrobenzotriazoles forming a tape along the b-axis of the crystal. These tapes stack along the c-axis through hydrogen bonds involving the water molecules and one of the nitro groups leading to a bidimensional structure. Solid-state 13C and 15N CPMAS NMR allow to confirm that the tautomer present is the 1H one. In DMSO-d6 solution the results are quite different and, based on GIAO/B3LYP/6-311++G(d,p) calculations, lead us to conclude that the major tautomer is the 5,6-dinitro-2H-benzotriazole, a surprising result that contradicts the rule that the major tautomer in solution coincides with the one present in the crystal. An anhydrous pseudopolymorph of 5,6-dinitro-1H-benzotriazole has been obtained as a non-crystalline form and from solid-state NMR and theoretical calculations, we conclude that it is an 1H-tautomer.

  19. Early development of Drosophila embryos requires Smc5/6 function during oogenesis.

    PubMed

    Tran, Martin; Tsarouhas, Vasilios; Kegel, Andreas

    2016-01-01

    Mutations in structural maintenance of chromosomes (Smc) proteins are frequently associated with chromosomal abnormalities commonly observed in developmental disorders. However, the role of Smc proteins in development still remains elusive. To investigate Smc5/6 function during early embryogenesis we examined smc5 and smc6 mutants of the fruit fly Drosophila melanogaster using a combination of reverse genetics and microscopy approaches. Smc5/6 exhibited a maternally contributed function in maintaining chromosome stability during early embryo development, which manifested as female subfertility in its absence. Loss of Smc5/6 caused an arrest and a considerable delay in embryo development accompanied by fragmented nuclei and increased anaphase-bridge formation, respectively. Surprisingly, early embryonic arrest was attributable to the absence of Smc5/6 during oogenesis, which resulted in insufficient repair of pre-meiotic and meiotic DNA double-strand breaks. Thus, our findings contribute to the understanding of Smc proteins in higher eukaryotic development by highlighting a maternal function in chromosome maintenance and a link between oogenesis and early embryogenesis. PMID:27288507

  20. Can 5-6 Year Old Children Orientate Themselves in a Cave?

    ERIC Educational Resources Information Center

    Jovignot, Francois

    1995-01-01

    Spatial capacities of 36 children ages 5-6 were tested in 3 experiments involving an electronic maze, map training and testing, and finding the way out of a cave using a map. All subjects could use simple maps; this ability improved with age. However, no subject navigated the cave without help, perhaps because of stress or task complexity. (SV)

  1. 2,2\\',3,3\\',4,4\\',5,5\\',6,6\\'-Decabromodiphenyl ether (BDE-209)

    Integrated Risk Information System (IRIS)

    2,2 ' , 3,3 ' , 4,4 ' , 5,5 ' , 6,6 ' - Decabromodiphenyl ether ( BDE - 209 ) ; CASRN 1163 - 19 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process

  2. Early development of Drosophila embryos requires Smc5/6 function during oogenesis

    PubMed Central

    Tran, Martin; Tsarouhas, Vasilios

    2016-01-01

    ABSTRACT Mutations in structural maintenance of chromosomes (Smc) proteins are frequently associated with chromosomal abnormalities commonly observed in developmental disorders. However, the role of Smc proteins in development still remains elusive. To investigate Smc5/6 function during early embryogenesis we examined smc5 and smc6 mutants of the fruit fly Drosophila melanogaster using a combination of reverse genetics and microscopy approaches. Smc5/6 exhibited a maternally contributed function in maintaining chromosome stability during early embryo development, which manifested as female subfertility in its absence. Loss of Smc5/6 caused an arrest and a considerable delay in embryo development accompanied by fragmented nuclei and increased anaphase-bridge formation, respectively. Surprisingly, early embryonic arrest was attributable to the absence of Smc5/6 during oogenesis, which resulted in insufficient repair of pre-meiotic and meiotic DNA double-strand breaks. Thus, our findings contribute to the understanding of Smc proteins in higher eukaryotic development by highlighting a maternal function in chromosome maintenance and a link between oogenesis and early embryogenesis. PMID:27288507

  3. DETERMINATION OF 3,5,6-TRICHLORO-2-PYRIDINOL (TCP) BY ELISA

    EPA Science Inventory

    A sensitive, competitive enzyme-linked immunosorbent assay (ELISA) for 3,5,6-trichloro-2pyridinol (TCP) has been developed to quantitate parts per billion (ppb) amounts of the analyte in urine. TCP is a major metabolite and environmental degradation product of the insecticide c...

  4. Pyrogen fever in rabbits pretreated with p-chlorophenylalanine or 5, 6-dihydroxytryptamine.

    PubMed

    Carruba, M O; Bächtold, H P

    1976-06-15

    The hyperthermic effect of a bacterial pyrogen has been studied in rabbits pretreated or not with p-chlorophenylalanine or 5, 6-dihydroxytryptamine. The results obtained indicate that a selective reduction of cerebral 5-hydroxytryptamine levels by these drugs do not significantly affect pyrogen hypertermia. PMID:133031

  5. IMMUNOHISTOCHEMICAL ANALYSIS OF ZNT1, 4, 5, 6, AND 7 IN THE MOUSE GASTROINTESTINAL TRACT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Expression of five zinc transporters (ZnT1, 4, 5, 6, and 7) of the Slc30 family in the mouse gastrointestinal tract was studied by immunohistochemical analysis. The results demonstrated unique expression patterns, levels, and cellular localization among ZnT proteins in the mouse gastrointestinal tra...

  6. Viscosity Measurements of Eclogite Melt up to 5.6 GPa and 2000 K

    NASA Astrophysics Data System (ADS)

    Liu, H.; Fei, Y.; Han, L.; Kono, Y.; Hou, M.; Zhao, Z.; Du, J.

    2014-12-01

    The melting and rheology of eclogite is critical for understanding the dynamics of the subduction zone and plate tectonic. Viscosity of eclogite melt as a function of depth is a key parameter to model the long-term chemical evolution of the subduction zone and volcanic magma. It also plays an important role in earthquakes and continent formation. However, the viscosity and rheology of eclogite melt remain poorly understood at high pressure and temperature. In this study, we have carried out in-situ falling-sphere viscometry measurements to determine the viscosity of eclogite melt from 1.3 to 5.6 GPa at temperatures between 1500 and 2000 K, using the Paris-Edinburgh cell at the 16-BM-B beamline of the High Pressure Collaborative Access Team (HPCAT) at the Advanced Photon Source. We used a natural eclogite sample with 47.7wt% SiO2. The viscosity (η) was calculated with the Stokes' equation. The viscosity of eclogite melt decreases between 1.3 and 5.6 GPa at 2000K. At 1.4 GPa and 2000K the viscosity is 0.43 Pa·s, whereas at 5.6 GPa and 2000 K it is 0.13Pa·s. No minimum in the viscosity of eclogite was found in the measured pressure range up to 5.6 GPa.

  7. Altitude Stress During Participation of Medical Congress.

    PubMed

    Kim, Soon Bae; Kim, Jong Sung; Kim, Sang Jun; Cho, Su Hee; Suh, Dae Chul

    2016-09-01

    Medical congresses often held in highlands. We reviewed several medical issues associated with altitude stress especially while physicians have participated medical congress held in high altitude. Altitude stress, also known as an acute mountain sickness (AMS), is caused by acute exposure to low oxygen level at high altitude which is defined as elevations at or above 1,200 m and AMS commonly occurs above 2,500 m. Altitude stress with various symptoms including insomnia can also be experienced in airplane. AMS and drunken state share many common features in symptoms, neurologic manifestations and even show multiple microbleeds in corpus callosum and white matter on MRI. Children are more susceptible to altitude stress than adults. Gradual ascent is the best method for the prevention of altitude stress. Adequate nutrition (mainly carbohydrates) and hydration are recommended. Consumption of alcohol can exacerbate the altitude-induced impairments in judgment and the visual senses and promote psychomotor dysfunction. For prevention or treatment of altitude stress, acetazolamide, phosphodiesterase inhibitors, dexamethasone and erythropoietin are helpful. Altitude stress can be experienced relatively often during participation of medical congress. It is necessary to remind the harmful effect of AMS because it can cause serious permanent organ damage even though the symptoms are negligible in most cases. PMID:27621942

  8. Altitude Stress During Participation of Medical Congress

    PubMed Central

    Kim, Soon Bae; Kim, Jong Sung; Kim, Sang Jun; Cho, Su Hee

    2016-01-01

    Medical congresses often held in highlands. We reviewed several medical issues associated with altitude stress especially while physicians have participated medical congress held in high altitude. Altitude stress, also known as an acute mountain sickness (AMS), is caused by acute exposure to low oxygen level at high altitude which is defined as elevations at or above 1,200 m and AMS commonly occurs above 2,500 m. Altitude stress with various symptoms including insomnia can also be experienced in airplane. AMS and drunken state share many common features in symptoms, neurologic manifestations and even show multiple microbleeds in corpus callosum and white matter on MRI. Children are more susceptible to altitude stress than adults. Gradual ascent is the best method for the prevention of altitude stress. Adequate nutrition (mainly carbohydrates) and hydration are recommended. Consumption of alcohol can exacerbate the altitude-induced impairments in judgment and the visual senses and promote psychomotor dysfunction. For prevention or treatment of altitude stress, acetazolamide, phosphodiesterase inhibitors, dexamethasone and erythropoietin are helpful. Altitude stress can be experienced relatively often during participation of medical congress. It is necessary to remind the harmful effect of AMS because it can cause serious permanent organ damage even though the symptoms are negligible in most cases. PMID:27621942

  9. ALT space shuttle barometric altimeter altitude analysis

    NASA Technical Reports Server (NTRS)

    Killen, R.

    1978-01-01

    The accuracy was analyzed of the barometric altimeters onboard the space shuttle orbiter. Altitude estimates from the air data systems including the operational instrumentation and the developmental flight instrumentation were obtained for each of the approach and landing test flights. By comparing the barometric altitude estimates to altitudes derived from radar tracking data filtered through a Kalman filter and fully corrected for atmospheric refraction, the errors in the barometric altitudes were shown to be 4 to 5 percent of the Kalman altitudes. By comparing the altitude determined from the true atmosphere derived from weather balloon data to the altitude determined from the U.S. Standard Atmosphere of 1962, it was determined that the assumption of the Standard Atmosphere equations contributes roughly 75 percent of the total error in the baro estimates. After correcting the barometric altitude estimates using an average summer model atmosphere computed for the average latitude of the space shuttle landing sites, the residual error in the altitude estimates was reduced to less than 373 feet. This corresponds to an error of less than 1.5 percent for altitudes above 4000 feet for all flights.

  10. Rocket Engine Altitude Simulation Technologies

    NASA Technical Reports Server (NTRS)

    Woods, Jody L.; Lansaw, John

    2010-01-01

    John C. Stennis Space Center is embarking on a very ambitious era in its rocket engine propulsion test history. The first new large rocket engine test stand to be built at Stennis Space Center in over 40 years is under construction. The new A3 Test Stand is designed to test very large (294,000 Ibf thrust) cryogenic propellant rocket engines at a simulated altitude of 100,000 feet. A3 Test Stand will have an engine testing chamber where the engine will be fired after the air in the chamber has been evacuated to a pressure at the simulated altitude of less than 0.16 PSIA. This will result in a very unique environment with extremely low pressures inside a very large chamber and ambient pressures outside this chamber. The test chamber is evacuated of air using a 2-stage diffuser / ejector system powered by 5000 lb/sec of steam produced by 27 chemical steam generators. This large amount of power and flow during an engine test will result in a significant acoustic and vibrational environment in and around A3 Test Stand.

  11. High-altitude reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Yazdi, Renee Anna

    1991-01-01

    At the equator the ozone layer ranges from 65,000 to 130,000+ ft, which is beyond the capabilities of the ER-2, NASA's current high-altitude reconnaissance aircraft. This project is geared to designing an aircraft that can study the ozone layer. The aircraft must be able to satisfy four mission profiles. The first is a polar mission that ranges from Chile to the South Pole and back to Chile, a total range of 6000 n.m. at 100,000 ft with a 2500-lb payload. The second mission is also a polar mission with a decreased altitude and an increased payload. For the third mission, the aircraft will take off at NASA Ames, cruise at 100,000 ft, and land in Chile. The final mission requires the aircraft to make an excursion to 120,000 ft. All four missions require that a subsonic Mach number be maintained because of constraints imposed by the air sampling equipment. Three aircraft configurations were determined to be the most suitable for meeting the requirements. The performance of each is analyzed to investigate the feasibility of the mission requirements.

  12. Rhubarb Enema Attenuates Renal Tubulointerstitial Fibrosis in 5/6 Nephrectomized Rats by Alleviating Indoxyl Sulfate Overload

    PubMed Central

    Lu, Fuhua; Liu, Xusheng; Zou, Chuan

    2015-01-01

    Aim To investigate the effects of rhubarb enema treatment using a 5/6 nephrectomized rat model and study its mechanisms. Methods Twenty-eight Sprague Dawley rats were divided into three groups: sham operation group (n = 8), 5/6 nephrectomized (5/6Nx) (n = 10), and 5/6Nx with rhubarb enema treatment (n = 10). The rhubarb enema was continuous for 1.0 month. Serum creatinine, serum indoxyl sulfate (IS) level, renal pathology, tubulointerstitial fibrosis, and renal oxidative stress were assessed. Results 5/6Nx rats showed increasing levels of serum creatinine and severe pathological lesions. Their serum creatinine levels obviously decreased after rhubarb enema treatment (P < 0.05 vs 5/6Nx group). The administration of rhubarb enema attenuated the histopathological changes in 5/6Nx rats. In addition, 5/6Nx rats showed an enhanced extent of tubulointerstitial fibrosis compared with sham rats, and administration of rhubarb enema to 5/6Nx rats ameliorated tubulointerstitial fibrosis. 5/6Nx rats showed increased serum levels of IS, renal oxidative stress, and NF-κB compared with sham rats, whereas administration of rhubarb enema to 5/6Nx rats decreased serum levels of IS, renal oxidative stress, and NF-κB levels. Conclusion Rhubarb enema treatment ameliorates tubulointerstitial fibrosis in the kidneys of 5/6Nx rats, most likely by alleviating IS overload and reducing kidney oxidative stress and inflammatory injury. PMID:26671452

  13. Constructions of Optimal (v,{4,5,6},1,Q)-OOCs

    NASA Astrophysics Data System (ADS)

    Li, Xiyang; Fan, Pingzhi; Wu, Dianhua

    Optical code-division multiple-access (OCDMA) is a promising technique for multimedia transmission in fiber-optic local-area networks (LANs). Variable-weight optical orthogonal codes (OOCs) can be used for OCDMA networks supporting multiple quality of services (QoS). Most constructions for optimal variable-weight OOCs have focused on the case where the number of distinct Hamming weights of all codewords is equal to two, and the codewords of weight 3 are normally included. In this letter, four explicit constructions of optimal (v,{4,5,6},1,Q)-OOCs are presented, and more new optimal (v,{4,5,6},1,Q)-OOCs are obtained via recursive constructions. These improve the existing results on optimal variable-weight OOCs with at least three distinct Hamming weights and minimum Hamming weight 4.

  14. Dihydro-5,6-dehydrokavain (DDK) from Alpinia zerumbet: Its Isolation, Synthesis, and Characterization.

    PubMed

    Xuan, Tran Dang; Teschke, Rolf

    2015-01-01

    Dihydro-5,6-dehydrokavain (DDK) is the major and most promising component of the tropical plant Alpinia zerumbet (shell ginger), a species of the ginger family Zingiberaceae. Alpinia zerumbet is known for its human use as a traditional herbal medicine, food, and dietary supplement. With its α-lactone ring, DDK belongs to the large chemical group of kavalactones, which are also found in kava (Piper methysticum), another herbal medicine; DDK is characterized by a double-bond linkage at positions 5,6 and the absence of a double-bond linkage at positions 7,8. This dissociates DDK from other kavalactones with their linkages at positions 7,8 and 5,6 that are both either completely saturated or unsaturated, or may have an unsaturated bond at the position 7,8 as well as a saturated bond at the position 5,6. DDK is easily identified and quantified by HPLC and GC. DDK contents in fresh leaves, stems and rhizomes range from 80 to 410 mg/g, requiring solvent extraction procedures to ensure high DDK yield. This is best achieved by hexane extraction from fresh rhizomes that were previously boiled in water, allowing DDK yields of up to 424 mg/g. Successful synthesis of DDK can be achieved by asymmetric pathways, whereas its simple chemical structure facilitates the synthesis of DDK derivatives by HCl hydrolysis. Thus, all synthesized products may be used for various commercial purposes, including the potential development of promising antiobesity pharmaceutical drugs, preparation of specific and safe dietary supplements, and use as effective natural herbicides or fungicides. PMID:26370954

  15. Conformational Changes in Inositol 1,3,4,5,6-Pentakisphosphate 2-Kinase upon Substrate Binding

    PubMed Central

    Baños-Sanz, José Ignacio; Sanz-Aparicio, Julia; Whitfield, Hayley; Hamilton, Chris; Brearley, Charles A.; González, Beatriz

    2012-01-01

    Inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IP5 2-K) catalyzes the synthesis of inositol 1,2,3,4,5,6-hexakisphosphate from ATP and IP5. Inositol 1,2,3,4,5,6-hexakisphosphate is implicated in crucial processes such as mRNA export, DNA editing, and phosphorus storage in plants. We previously solved the first structure of an IP5 2-K, which shed light on aspects of substrate recognition. However, failure of IP5 2-K to crystallize in the absence of inositide prompted us to study putative conformational changes upon substrate binding. We have made mutations to residues on a region of the protein that produces a clasp over the active site. A W129A mutant allowed us to capture IP5 2-K in its different conformations by crystallography. Thus, the IP5 2-K apo-form structure displays an open conformation, whereas the nucleotide-bound form shows a half-closed conformation, in contrast to the inositide-bound form obtained previously in a closed conformation. Both nucleotide and inositide binding produce large conformational changes that can be understood as two rigid domain movements, although local changes were also observed. Changes in intrinsic fluorescence upon nucleotide and inositide binding are in agreement with the crystallographic findings. Our work suggests that the clasp might be involved in enzyme kinetics, with the N-terminal lobe being essential for inositide binding and subsequent conformational changes. We also show how IP5 2-K discriminates between inositol 1,3,4,5-tetrakisphosphate and 3,4,5,6-tetrakisphosphate enantiomers and that substrate preference can be manipulated by Arg130 mutation. Altogether, these results provide a framework for rational design of specific inhibitors with potential applications as biological tools for in vivo studies, which could assist in the identification of novel roles for IP5 2-K in mammals. PMID:22745128

  16. Cytokeratin 5/6 and P63 immunophenotype of thyroid lymphoepithelial complexes.

    PubMed

    Handra-Luca, Adriana; Dragoescu, Ema

    2016-08-01

    Thyroid lymphoepithelial complexes (LECos) are rare, being reported in lymphoma, Graves-Basedow disease, Hashimoto thyroiditis, pericarcinomatous thyroid or in the context of branchial cleft-like cysts. Here we report immunohistochemical expression of cytokeratin 5/6, P63 and TTF1 in 6 cases of thyroid LECos. Two cases had carbimazole treatment for hyperthyroidia and Graves disease. Anti-thyroglobulin, -thyroperoxidase or -TSH antibodies were detected in 4 cases. NSAID or poviodone iodine allergy were present in 2 cases. The treatment consisted in total thyroidectomy or lobectomy. Microscopy showed nodular goiter and focal lymphocytic thyroiditis. Basaloid LECos were seen in all thyroids while squamoid LECos in 2. Associated lesions were papillary thyroid microcarcinoma (2 cases), solid cell nest, thyroglosal duct remnant, lymphoepithelial cyst and thymus-parathyroid unit (one case each). Cytokeratin 5/6 was expressed in both squamoid and basaloid LECos along with P63. TTF1 expression was faint or absent. In conclusion LECos may occur in the context of autoimmune thyroiditis or of a specific immune susceptibility background. The expression of CK5/6 and of P63 suggests a squamous differentiation including in the basaloid LECos. The etiologic relevance of these immunostainings remains limited although rather suggestive of a metaplastic process than of migration-abnormalities. PMID:27130144

  17. A case of T2 radiculopathy after anterior C5-6 fusion.

    PubMed

    Takenaka, Tomofumi; Ohnishi, Yu-Ichiro; Oshino, Satoru

    2016-01-01

    Thoracic radiculopathy is a rare entity. Symptomatic adjacent-segment disease after anterior cervical fusion occurs commonly in the lower cervical spine segment. We describe the clinical presentation and treatment of T2 radiculopathy after C5-6 anterior fusion. A 60-year-old man presented with the right axillary pain for 3 months. He had undergone C5-6 anterior fusion for cervical spondylosis 5 years prior. Computed tomography (CT) and magnetic resonance images showed T2-3 degenerative disease. C5-6 anterior fusion exacerbated the T2-3 segment involved in the patient's scoliotic deformity. After 2 months of conservative treatment, we decompressed the T2 foramen via T2-3 hemilaminectomy and partial facet resection. After the surgery, his symptoms disappeared. T2 radiculopathy is rare but should be considered in the differential diagnosis of chest pain. Surgeons should pay attention not only to adjacent-segment disease but also to segmental degeneration at the apex of a scoliotic deformity after cervical anterior fusion. PMID:27197614

  18. Sudden Infant Death Syndrome and Residential Altitude

    PubMed Central

    Shore, Supriya; Bandle, Brian; Niermeyer, Susan; Bol, Kirk A.; Khanna, Amber

    2015-01-01

    BACKGROUND: Theories of sudden infant death syndrome (SIDS) suggest hypoxia is a common pathway. Infants living at altitude have evidence of hypoxia; however, the association between SIDS incidence and infant residential altitude has not been well studied. METHODS: We performed a retrospective cohort study by using data from the Colorado birth and death registries from 2007 to 2012. Infant residential altitude was determined by geocoding maternal residential address. Logistic regression was used to determine adjusted association between residential altitude and SIDS. We evaluated the impact of the Back to Sleep campaign across various altitudes in an extended cohort from 1990 to 2012 to assess for interaction between sleep position and altitude. RESULTS: A total of 393 216 infants born between 2007 and 2012 were included in the primary cohort (51.4% boys; mean birth weight 3194 ± 558 g). Overall, 79.6% infants resided at altitude <6000 feet, 18.5% at 6000 to 8000 feet, and 1.9% at >8000 feet. There were no meaningful differences in maternal characteristics across altitude groups. Compared with residence <6000 feet, residence at high altitude (>8000 feet), was associated with an adjusted increased risk of SIDS (odds ratio 2.30; 95% confidence interval 1.01–5.24). Before the Back to Sleep campaign, the incidence of SIDS in Colorado was 1.99/1000 live births and dropped to 0.57/1000 live births after its implementation. The Back to Sleep campaign had similar effect across different altitudes (P = .45). CONCLUSIONS: Residence at high altitude was significantly associated with an increased adjusted risk for SIDS. Impact of the Back to Sleep campaign was similar across various altitudes. PMID:26009621

  19. Measurement of Altitude in Blind Flying

    NASA Technical Reports Server (NTRS)

    Brombacher, W G

    1934-01-01

    In this note, instruments for measuring altitude and rate of change of altitude in blind flying and landing of aircraft and their performance are discussed. Of those indicating the altitude above ground level, the sonic altimeter is the most promising. Its present bulk, intermittent operation, and more or less unsatisfactory means of indication are serious drawbacks to its use. The sensitive type aneroid altimeter is also discussed and errors in flying at a pressure level and in landing are discussed in detail.

  20. Hormonal contraceptives and travel to high altitude.

    PubMed

    Keyes, Linda E

    2015-03-01

    Women frequently ask about the safety and efficacy of using hormonal contraception (HC), either oral contraceptive pills (OC) or other forms, when traveling to high altitude locales. What are the risks and benefits of using HC at high altitude? Does HC affect acclimatization, exercise performance, or occurrence of acute mountain sickness? This article reviews current data regarding the risks and benefits of HC at high altitude, both demonstrated and theoretical, with the aim of helping health care providers to advise women traveling above 2500 meters. Most healthy women can safely use HC when traveling to high altitude, but should be aware of the potential risks and inconveniences. PMID:25759908

  1. Low Altitude Space Communication System

    NASA Astrophysics Data System (ADS)

    Namiki, Michiyoshi; Matsuzaka, Yukihiko; Honda, Hideyuki; Toriumi, Michihiko; Kamioka, Eiji; Saito, Yoshitaka; Izutsu, Naoki; Ohta, Sigeo; Yamagami, Takamasa; Yajima, Nobuyuki; Hirosawa, Haruto; Ohya, Nobuhiko; Takezawa, Fukashi; Yamaguchi, Kenji

    We describe a new Low Altitude Space Communication System (LASCOS), which was completed in 1996 by the Institute of Space and Astronautical Science in Japan. This system consists of a mobile balloon tracking and receiving station and networks which connect them to the Sanriku Balloon Center in Iwate Municipality and the Institute of Space and Astronautical Science (ISAS) in Kanagawa Municipality. This station and the SBC receiving station are connected via telephone lines, i. e. an Integrated Services Digital Network (ISDN) or an analog communication network. Balloon trajectory monitoring, telecommand transmission operation and telemetry data acquisition can be done from any computer terminal through the LASCOS. LASCOS has built-in flexibility to adapt to a foreign balloon station. The number of individuals necessary to operate it minimum. LASCOS will be used for long range tracking and balloon expedition. We present the results of its first test with an actual balloon flight

  2. The high-altitude brain.

    PubMed

    Hornbein, T F

    2001-09-01

    The highest place on our planet, Mount Everest (8850 m), appears to be close to the limit of how high an acclimatized human can go, albeit slowly. In this paper, I will explore the possibility that what limits human performance at such extreme degrees of hypoxia is the availability of oxygen to the brain. Also, one of the known costs of such extreme exposure is residual mild impairment of performance on neuropsychometric tests after return to sea level, implying injury to brain cells. That such injury could occur in the absence of any overt impairment of function, much less without loss of consciousness, is unexpected. I will speculate about physiological mechanisms that might cause or contribute to both decrements in real-time performance while at altitude and residual deficits for a time after return to low elevations; the effects of hypoxia on brain cells are an even greater puzzle at the present time. PMID:11581326

  3. Fire Fighting from High Altitude

    NASA Technical Reports Server (NTRS)

    Cobleigh, Brent; Ambrosia, Vince

    2007-01-01

    A viewgraph presentation on high altitude fire fighting is shown. The topics include: 1) Yellowstone Fire - 1988; 2) 2006 Western States Fire Mission Over-View; 3) AMS-Wildfire Scanner; 4) October 24-25 Mission: Yosemite NP and NF; 5) October 24-25 Mission MODIS Overpass; 6) October 24-25 Mission Highlights; 7) October 28-29 Mission Esperanza Fire, California; 8) Response to the Esperanza Fire in Southern California -- Timeline Oct 27-29 2006; 9) October 28-29 Mission Esperanza Fire Altair Flight Routing; 10) October 28-29 Mission Esperanza Fire Altair Over-Flights; 11) October 28-29 Mission Highlights; 12) Results from the Esperanza Fire Response; 13) 2007 Western States Fire Mission; and 14) Western States UAS Fire Mission 2007

  4. Environmental dynamics at orbital altitudes

    NASA Technical Reports Server (NTRS)

    Karr, G. R.

    1976-01-01

    The influence of real satellite aerodynamics on the determination of upper atmospheric density was investigated. A method of analysis of satellite drag data is presented which includes the effect of satellite lift and the variation in aerodynamic properties around the orbit. The studies indicate that satellite lift may be responsible for the observed orbit precession rather than a super rotation of the upper atmosphere. The influence of simplifying assumptions concerning the aerodynamics of objects in falling sphere analysis were evaluated and an improved method of analysis was developed. Wind tunnel data was used to develop more accurate drag coefficient relationships for studying altitudes between 80 and 120 Km. The improved drag coefficient relationships revealed a considerable error in previous falling sphere drag interpretation. These data were reanalyzed using the more accurate relationships. Theoretical investigations of the drag coefficient in the very low speed ratio region were also conducted.

  5. Stepped nozzle

    DOEpatents

    Sutton, G.P.

    1998-07-14

    An insert is described which allows a supersonic nozzle of a rocket propulsion system to operate at two or more different nozzle area ratios. This provides an improved vehicle flight performance or increased payload. The insert has significant advantages over existing devices for increasing nozzle area ratios. The insert is temporarily fastened by a simple retaining mechanism to the aft end of the diverging segment of the nozzle and provides for a multi-step variation of nozzle area ratio. When mounted in place, the insert provides the nozzle with a low nozzle area ratio. During flight, the retaining mechanism is released and the insert ejected thereby providing a high nozzle area ratio in the diverging nozzle segment. 5 figs.

  6. Stepped nozzle

    DOEpatents

    Sutton, George P.

    1998-01-01

    An insert which allows a supersonic nozzle of a rocket propulsion system to operate at two or more different nozzle area ratios. This provides an improved vehicle flight performance or increased payload. The insert has significant advantages over existing devices for increasing nozzle area ratios. The insert is temporarily fastened by a simple retaining mechanism to the aft end of the diverging segment of the nozzle and provides for a multi-step variation of nozzle area ratio. When mounted in place, the insert provides the nozzle with a low nozzle area ratio. During flight, the retaining mechanism is released and the insert ejected thereby providing a high nozzle area ratio in the diverging nozzle segment.

  7. 75 FR 24790 - IFR Altitudes; Miscellaneous Amendments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-06

    ...This amendment adopts miscellaneous amendments to the required IFR (instrument flight rules) altitudes and changeover points for certain Federal Airways, jet routes, or direct routes for which a minimum or maximum en route authorized IFR altitude is prescribed. This regulatory action is needed because of changes occurring in the National Airspace System. These changes are designed to provide......

  8. 76 FR 11675 - IFR Altitudes; Miscellaneous Amendments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-03

    ...This amendment adopts miscellaneous amendments to the required IFR (instrument flight rules) altitudes and changeover points for certain Federal airways, jet routes, or direct routes for which a minimum or maximum en route authorized IFR altitude is prescribed. This regulatory action is needed because of changes occurring in the National Airspace System. These changes are designed to provide......

  9. High Altitude Illnesses in Hawai‘i

    PubMed Central

    2014-01-01

    High Altitude Headache (HAH), Acute Mountain Sickness (AMS), and High Altitude Cerebral Edema (HACE) are all high altitude related illnesses in order of severity from the mildly symptomatic to the potentially life-threatening. High altitude illnesses occur when travelers ascend to high altitudes too rapidly, which does not allow enough time for the body to adjust. Slow graded ascent to the desired altitude and termination of ascent if AMS symptoms present are keys to illness prevention. Early recognition and rapid intervention of AMS can halt progression to HACE. Pharmacologic prophylaxis with acetazolamide is a proven method of prevention and treatment of high altitude illness. If prevention fails then treatment modalities include supplemental oxygen, supportive therapy, hyperbaric treatment, and dexamethasone. Given the multitude of visitors to the mountains of Hawai‘i, high altitude illness will continue to persist as a prevalent local condition. This paper will emphasize the prevention and early diagnosis of AMS so that the illness does not progress to HACE. PMID:25478293

  10. An Optical Altitude Indicator for Night Landing

    NASA Technical Reports Server (NTRS)

    Warner, John A C

    1923-01-01

    One of the most ingenious of the devices intended for use in night landing, especially emergency landing, is a very simple optical instrument known as the Jenkins night altitude indicator. The design and operation of this instrument, which allows a pilot to determine the altitude of the aircraft, is discussed. The author discusses various modifications and improvements that might be made to the instrument.

  11. Linear polarization variations modulo 5.6 days in HDE 226868

    NASA Technical Reports Server (NTRS)

    Nolt, I. G.; Kemp, J. C.; Rudy, R. J.; Southwick, R. G.; Radostitz, J. V.; Caroff, L. J.

    1975-01-01

    Results are reported for observations of variations in the linear polarization in HDE 226868 (the optical counterpart of Cyg X-1) made with a photoelastic polarimeter and a U-filter. The UV linear-polarization variations, as folded on the 5.6-day orbital period, are found to have amplitudes of 0.25% and position-angle changes of 2.7 deg. These results are shown to be consistent with the geometry and phasing required by the model of the binary system.

  12. Rare-earth plasma extreme ultraviolet sources at 6.5-6.7 nm

    SciTech Connect

    Otsuka, Takamitsu; Higashiguchi, Takeshi; Yugami, Noboru; Yatagai, Toyohiko; Kilbane, Deirdre; White, John; Dunne, Padraig; O'Sullivan, Gerry; Jiang, Weihua; Endo, Akira

    2010-09-13

    We have demonstrated a laser-produced plasma extreme ultraviolet source operating in the 6.5-6.7 nm region based on rare-earth targets of Gd and Tb coupled with a Mo/B{sub 4}C multilayer mirror. Multiply charged ions produce strong resonance emission lines, which combine to yield an intense unresolved transition array. The spectra of these resonant lines around 6.7 nm (in-band: 6.7 nm {+-}1%) suggest that the in-band emission increases with increased plasma volume by suppressing the plasma hydrodynamic expansion loss at an electron temperature of about 50 eV, resulting in maximized emission.

  13. Photophysics of poly(2,3,4,5,6-pentafluorostyrene) film

    SciTech Connect

    O'Connor, D.B.; Scott, G.W. ); Coulter, D.R.; Miskowski, V.M.; Yavrouian, A. )

    1990-08-09

    The temperature-dependent steady-state emission, emission polarization anisotropy, and fluorescence kinetics of poly(2,3,4,5,6-pentafluorostyrene) film are reported. Two interconverting excited-state conformations of the chromophore have been identified. The fluorescence of the higher energy conformation results from excitation on the red edge of the polymer absorption band at temperatures below 180 K. The energy barrier for conversion of the higher energy conformer to the lower energy conformer is estimated to be E/hc = 27 {plus minus} 7 cm{sup {minus}1}. Electronic energy migration is not evident in this polymer.

  14. Jupiter's High-Altitude Clouds

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The New Horizons Multispectral Visible Imaging Camera (MVIC) snapped this incredibly detailed picture of Jupiter's high-altitude clouds starting at 06:00 Universal Time on February 28, 2007, when the spacecraft was only 2.3 million kilometers (1.4 million miles) from the solar system's largest planet. Features as small as 50 kilometers (30 miles) are visible. The image was taken through a narrow filter centered on a methane absorption band near 890 nanometers, a considerably redder wavelength than what the eye can see. Images taken through this filter preferentially pick out clouds that are relatively high in the sky of this gas giant planet because sunlight at the wavelengths transmitted by the filter is completely absorbed by the methane gas that permeates Jupiter's atmosphere before it can reach the lower clouds.

    The image reveals a range of diverse features. The south pole is capped with a haze of small particles probably created by the precipitation of charged particles into the polar regions during auroral activity. Just north of the cap is a well-formed anticyclonic vortex with rising white thunderheads at its core. Slightly north of the vortex are the tendrils of some rather disorganized storms and more pinpoint-like thunderheads. The dark 'measles' that appear a bit farther north are actually cloud-free regions where light is completely absorbed by the methane gas and essentially disappears from view. The wind action considerably picks up in the equatorial regions where giant plumes are stretched into a long wave pattern. Proceeding north of the equator, cirrus-like clouds are shredded by winds reaching speeds of up to 400 miles per hour, and more pinpoint-like thunderheads are visible. Although some of the famous belt and zone structure of Jupiter's atmosphere is washed out when viewed at this wavelength, the relatively thin North Temperate Belt shows up quite nicely, as does a series of waves just north of the belt. The north polar region of

  15. Sleep at high altitude: guesses and facts.

    PubMed

    Bloch, Konrad E; Buenzli, Jana C; Latshang, Tsogyal D; Ulrich, Silvia

    2015-12-15

    Lowlanders commonly report a poor sleep quality during the first few nights after arriving at high altitude. Polysomnographic studies reveal that reductions in slow wave sleep are the most consistent altitude-induced changes in sleep structure identified by visual scoring. Quantitative spectral analyses of the sleep electroencephalogram have confirmed an altitude-related reduction in the low-frequency power (0.8-4.6 Hz). Although some studies suggest an increase in arousals from sleep at high altitude, this is not a consistent finding. Whether sleep instability at high altitude is triggered by periodic breathing or vice versa is still uncertain. Overnight changes in slow wave-derived encephalographic measures of neuronal synchronization in healthy subjects were less pronounced at moderately high (2,590 m) compared with low altitude (490 m), and this was associated with a decline in sleep-related memory consolidation. Correspondingly, exacerbation of breathing and sleep disturbances experienced by lowlanders with obstructive sleep apnea during a stay at 2,590 m was associated with poor performance in driving simulator tests. These findings suggest that altitude-related alterations in sleep may adversely affect daytime performance. Despite recent advances in our understanding of sleep at altitude, further research is required to better establish the role of gender and age in alterations of sleep at different altitudes, to determine the influence of acclimatization and of altitude-related illness, and to uncover the characteristics of sleep in highlanders that may serve as a study paradigm of sleep in patients exposed to chronic hypoxia due to cardiorespiratory disease. PMID:26229000

  16. Diving at altitude: from definition to practice.

    PubMed

    Egi, S Murat; Pieri, Massimo; Marroni, Alessandro

    2014-01-01

    Diving above sea level has different motivations for recreational, military, commercial and scientific activities. Despite the apparently wide practice of inland diving, there are three major discrepancies about diving at altitude: threshold elevation that requires changes in sea level procedures; upper altitude limit of the applicability of these modifications; and independent validation of altitude adaptation methods of decompression algorithms. The first problem is solved by converting the normal fluctuation in barometric pressure to an altitude equivalent. Based on the barometric variations recorded from a meteorological center, it is possible to suggest 600 meters as a threshold for classifying a dive as an "altitude" dive. The second problem is solved by proposing the threshold altitude of aviation (2,400 meters) to classify "high" altitude dives. The DAN (Divers Alert Network) Europe diving database (DB) is analyzed to solve the third problem. The database consists of 65,050 dives collected from different dive computers. A total of 1,467 dives were found to be classified as altitude dives. However, by checking the elevation according to the logged geographical coordinates, 1,284 dives were disqualified because the altitude setting had been used as a conservative setting by the dive computer despite the fact that the dive was made at sea level. Furthermore, according to the description put forward in this manuscript, 72 dives were disqualified because the surface level elevation is lower than 600 meters. The number of field data (111 dives) is still very low to use for the validation of any particular method of altitude adaptation concerning decompression algorithms. PMID:25562941

  17. Neurological conditions at altitude that fall outside the usual definition of altitude sickness.

    PubMed

    Basnyat, Buddha; Wu, Tianyi; Gertsch, Jeffrey H

    2004-01-01

    Altitude sickness in its commonly recognized forms consists of acute mountain sickness and the two life-threatening forms, high altitude cerebral and pulmonary edema. Less well known are other conditions, chiefly neurological, that may arise completely outside the usual definition of altitude sickness. These, often focal, neurological conditions are important to recognize so that they do not become categorized as altitude sickness because, besides oxygen and descent, treatment may be vastly different. Transient ischemic attacks, cerebral venous thrombosis, seizures, syncope, double vision, and scotomas are some of the well-documented neurological disturbances at high altitude discussed here in order to enhance their recognition and treatment. PMID:15265338

  18. High altitude aircraft flight tests

    NASA Astrophysics Data System (ADS)

    Helmken, Henry; Emmons, Peter; Homeyer, David

    1996-03-01

    In order to make low earth orbit L-band propagation measurements and test new voice communication concepts, a payload was proposed and accepted for flight aboard the COMET (now METEOR) spacecraft. This Low Earth Orbiting EXperiment payload (LEOEX) was designed and developed by Motorola Inc. and sponsored by the Space Communications Technology Center (SCTC), a NASA Center for the Commercial Development of Space (CCDS) located at Florida Atlantic University. In order to verify the LEOEX payload for satellite operation and obtain some preliminary propagation data, a series of 9 high altitude aircraft (SR-71 and ER-2) flight tests were conducted. These flights took place during a period of 7 months, from October 1993 to April 1994. This paper will summarize the operation of the LEOEX payload and the particular configuration used for these flights. The series of flyby tests were very successful and demonstrated how bi-directional, Time Division Multiple Access (TDMA) voice communication will work in space-to-ground L-band channels. The flight tests also acquired propagation data which will be representative of L-band Low Earth Orbiting (LEO) communication systems. In addition to verifying the LEOEX system operation, it also uncovered and ultimately aided the resolution of several key technical issues associated with the payload.

  19. Smc5/6-Mms21 Prevents and Eliminates Inappropriate Recombination Intermediates in Meiosis

    PubMed Central

    Xaver, Martin; Huang, Lingzhi; Chen, Doris; Klein, Franz

    2013-01-01

    Repairing broken chromosomes via joint molecule (JM) intermediates is hazardous and therefore strictly controlled in most organisms. Also in budding yeast meiosis, where production of enough crossovers via JMs is imperative, only a subset of DNA breaks are repaired via JMs, closely regulated by the ZMM pathway. The other breaks are repaired to non-crossovers, avoiding JM formation, through pathways that require the BLM/Sgs1 helicase. “Rogue” JMs that escape the ZMM pathway and BLM/Sgs1 are eliminated before metaphase by resolvases like Mus81-Mms4 to prevent chromosome nondisjunction. Here, we report the requirement of Smc5/6-Mms21 for antagonizing rogue JMs via two mechanisms; destabilizing early intermediates and resolving JMs. Elimination of the Mms21 SUMO E3-ligase domain leads to transient JM accumulation, depending on Mus81-Mms4 for resolution. Absence of Smc6 leads to persistent rogue JMs accumulation, preventing chromatin separation. We propose that the Smc5/6-Mms21 complex antagonizes toxic JMs by coordinating helicases and resolvases at D-Loops and HJs, respectively. PMID:24385936

  20. Thermal responses to 5. 6-GHz radiofrequency radiation in anesthetized rats. Effect of chlorpromazine

    SciTech Connect

    Jauchem, J.R.; Frei, M.R.; Heinmets, F.

    1988-01-01

    Anesthetized rats were exposed to 5.6-GHz continuous-wave radiofrequency radiation (RFR) at an average power density of 60 mW/Sq. cm (average specific absorption rate 12 W/kg). Exposure was performed to raise colonic temperature from 38.5 to 39.5C. Following acute administration of chlorpromazine, body temperature exhibited a faster return to baseline temperature when exposure was discontinued. When exposure was initiated at 38.5C and continued until lethal temperature resulted, chlorpromazine-treated animals exhibited significantly shorter survival times than saline-treated animals. Thus, although chlorpromazine enhanced thermoregulatory efficiency at colonic temperature below 39.5 deg C, the drug caused increased susceptibility to terminal RFR. The present results, when compared with previous studies of irradiation at 2.8 GHz, indicate that the effects of chlorpromazine on thermal response to RFR during intermittent and terminal exposure are similar at both 2.8 and 5.6 GHz.

  1. Thermal responses to 5. 6-GHz radiofrequency radiation in anesthetized rats: effect of chlorpromazine

    SciTech Connect

    Jauchem, J.R.; Frei, M.R.; Heinmets, F.

    1988-01-01

    Anesthetized rats were exposed to 5.6-GHz continuous wave radiofrequency radiation at an average power density of 60 mW/cm2 (average specific absorption rate 12 W/kg). Exposure was performed to raise colonic temperature from 38.5 to 39.5 degrees C. Following acute administration of chlorpromazine, body temperature exhibited a faster return to baseline temperature when exposure was discontinued. When exposure was initiated at 38.5 degrees C and continued until lethal temperatures resulted, chlorpromazine-treated animals exhibited significantly shorter survival times than saline-treated animals. Thus, although chlorpromazine enhanced thermo-regulatory efficiency at colonic temperatures below 39.5 degrees C, the drug caused increased susceptibility to terminal radiofrequency radiation exposure. The present results, when compared to previous studies of irradiation at 2.8 GHz, indicate that the effects of chlorpromazine on thermal responses to RFR during intermittent and terminal exposure are similar at both 2.8 and 5.6 GHz.

  2. MnTBAP Therapy Attenuates Renal Fibrosis in Mice with 5/6 Nephrectomy

    PubMed Central

    Yu, Jing; Mao, Song; Zhang, Yue; Gong, Wei; Jia, Zhanjun; Huang, Songming; Zhang, Aihua

    2016-01-01

    Renal fibrosis is a common pathological feature of all kinds of chronic kidney diseases (CKDs) with uncertain mechanisms. Accumulating evidence demonstrated an important role of oxidative stress in the pathogenesis of CKD. Here we hypothesized that MnTBAP (manganese (III) tetrakis (4-benzoic acid)porphyrin chloride), a cell-permeable mimic of superoxide dismutase (SOD), may protect against the fibrotic response in CKD by antagonizing oxidative stress. To verify this hypothesis, we performed experiments in tubular epithelial cells and mice with 5/6 nephrectomy (Nx). In mouse tubular epithelial cells, TGF-β1 induced a significant transition to fibrotic phenotype in line with a remarkable mitochondrial dysfunction, which was markedly improved by MnTBAP (1.14 μM) pretreatment. In remnant kidneys of 5/6 Nx mice, tubulointerstitial fibrosis occurred in parallel with mitochondrial abnormality in renal tubular cells. Administration of MnTBAP significantly attenuated the deposition of extracellular matrix as evidenced by the blocked expressions of fibronectin, collagen I, and collagen III. Masson staining also displayed an ameliorated accumulation of collagenous matrix in MnTBAP-treated mice. Moreover, MnTBAP also significantly improved the severity of proteinuria without altering CKD-related hypertension. Collectively, MnTBAP therapy served as a promising strategy in preventing renal fibrosis in CKDs possibly via antagonizing mitochondrial-derived oxidative stress and subsequent protection of mitochondrial function. PMID:26989454

  3. Excision repair of 5,6-dihydroxydihydrothymine from the DNA of Micrococcus radiodurans

    SciTech Connect

    Targovnik, H.S.; Hariharan, P.V.

    1980-08-01

    One of the major ionizing radiation products, 5,6-dihydroxydihydrothymine (thymine glycol), was measured in the DNA of Micrococcus radiodurans following exposure of cells to 6.8-MeV electrons or 254-nm ultraviolet light. Removal of 5,6-dihydroxydihydrothymine was measured in both an ionizing radiation-sensitive strain (262) and a highly radioresistant strain (the wild type W/sup +/) of Micrococcus radiodurans. Within 30 min of incubation (33/sup 0/C) following exposure to ultraviolet light (2400 J/m/sup 2/) approximately 60% of the thymine glycols were excised, whereas in the case of ionizing radiation (250 krad) only 35% were removed from the cellular DNA of the wild-type strain. In contrast less than 50% of the thymine glycols were excised from the sensitive strain. The amount of DNA degradation induced by radiation was less than 10% in both strains. The results suggest a possible correlation between reduced excision repair of base damage and increased radiation sensitivity.

  4. Destabilized SMC5/6 complex leads to chromosome breakage syndrome with severe lung disease.

    PubMed

    van der Crabben, Saskia N; Hennus, Marije P; McGregor, Grant A; Ritter, Deborah I; Nagamani, Sandesh C S; Wells, Owen S; Harakalova, Magdalena; Chinn, Ivan K; Alt, Aaron; Vondrova, Lucie; Hochstenbach, Ron; van Montfrans, Joris M; Terheggen-Lagro, Suzanne W; van Lieshout, Stef; van Roosmalen, Markus J; Renkens, Ivo; Duran, Karen; Nijman, Isaac J; Kloosterman, Wigard P; Hennekam, Eric; Orange, Jordan S; van Hasselt, Peter M; Wheeler, David A; Palecek, Jan J; Lehmann, Alan R; Oliver, Antony W; Pearl, Laurence H; Plon, Sharon E; Murray, Johanne M; van Haaften, Gijs

    2016-08-01

    The structural maintenance of chromosomes (SMC) family of proteins supports mitotic proliferation, meiosis, and DNA repair to control genomic stability. Impairments in chromosome maintenance are linked to rare chromosome breakage disorders. Here, we have identified a chromosome breakage syndrome associated with severe lung disease in early childhood. Four children from two unrelated kindreds died of severe pulmonary disease during infancy following viral pneumonia with evidence of combined T and B cell immunodeficiency. Whole exome sequencing revealed biallelic missense mutations in the NSMCE3 (also known as NDNL2) gene, which encodes a subunit of the SMC5/6 complex that is essential for DNA damage response and chromosome segregation. The NSMCE3 mutations disrupted interactions within the SMC5/6 complex, leading to destabilization of the complex. Patient cells showed chromosome rearrangements, micronuclei, sensitivity to replication stress and DNA damage, and defective homologous recombination. This work associates missense mutations in NSMCE3 with an autosomal recessive chromosome breakage syndrome that leads to defective T and B cell function and acute respiratory distress syndrome in early childhood. PMID:27427983

  5. Structural basis of Wnt signaling inhibition by Dickkopf binding to LRP5/6

    PubMed Central

    Ahn, Victoria E.; Chu, Matthew Ling-Hon; Choi, Hee-Jung; Tran, Denise; Abo, Arie; Weis, William I.

    2011-01-01

    Summary LDL receptor-related proteins 5 and 6 (LRP5/6) are co-receptors for Wnt growth factors, and also bind Dkk proteins, secreted inhibitors of Wnt signaling. The LRP5/6 ectodomain contains four β-propeller/EGF-like domain repeats. The first two repeats (LRP6(1-2)) bind to several Wnt variants, whereas LRP6(3-4) binds other Wnts. We present the crystal structure of the Dkk1 C-terminal domain bound to LRP6(3-4), and show that the Dkk1 N-terminal domain binds to LRP6(1-2), demonstrating that a single Dkk1 molecule can bind to both portions of the LRP6 ectodomain and thereby inhibit different Wnts. Small-angle x-ray scattering analysis of LRP6(1-4) bound to a non-inhibitory antibody fragment or to full-length Dkk1 shows that in both cases the ectodomain adopts a curved conformation that places the first three repeats at a similar height relative to the membrane. Thus, Wnts bound to either portion of the LRP6 ectodomain likely bear a similar spatial relationship to Frizzled co-receptors. PMID:22000856

  6. Hemoglobin Mass and Aerobic Performance at Moderate Altitude in Elite Athletes.

    PubMed

    Wehrlin, Jon Peter; Marti, Bernard; Hallén, Jostein

    2016-01-01

    Fore more than a decade, the live high-train low (LHTL) approach, developed by Levine and Stray-Gundersen, has been widely used by elite endurance athletes. Originally, it was pointed out, that by living at moderate altitude, athletes should benefit from an increased red cell volume (RCV) and hemoglobin mass (Hbmass), while the training at low altitudes should prevent the disadvantage of reduced training intensity at moderate altitude. VO2max is reduced linearly by about 6-8 % per 1000 m increasing altitude in elite athletes from sea level to 3000 m, with corresponding higher relative training intensities for the same absolute work load. With 2 weeks of acclimatization, this initial deficit can be reduced by about one half. It has been debated during the last years whether sea-level training or exposure to moderate altitude increases RCV and Hbmass in elite endurance athletes. Studies which directly measured Hbmass with the optimized CO-rebreathing technique demonstrated that Hbmass in endurance athletes is not influenced by sea-level training. We documented that Hbmass is not increased after 3 years of training in national team cross-country skiers. When athletes are exposed to moderate altitude, new studies support the argument that it is possible to increase Hbmass temporarily by 5-6 %, provided that athletes spend >400 h at altitudes above 2300-2500 m. However, this effect size is smaller than the reported 10-14 % higher Hbmass values of endurance athletes living permanently at 2600 m. It remains to be investigated whether endurance athletes reach these values with a series of LHTL camps. PMID:27343108

  7. Multicomponent Double Diels-Alder/Nazarov Tandem Cyclization of Symmetric Cross-Conjugated Diynones to Generate [6-5-6] Tricyclic Products.

    PubMed

    Carmichael, Rachael A; Chalifoux, Wesley A

    2016-06-20

    The construction of complex polycyclic terpenoid products in an efficient and step-economical manner using multicomponent and tandem processes is highly valuable. Herein, we report a tandem cyclization sequence that initiates with a multicomponent double Diels-Alder reaction of cross-conjugated diynones, followed by a Nazarov cyclization to efficiently produce [6-5-6] tricyclic products with excellent regio- and diastereoselectivity. This methodology generates five new carbon-carbon bonds, three rings, quaternary or vicinal quaternary carbons, and stereogenic centers in a one-pot reaction. PMID:27124516

  8. High altitude syndromes at intermediate altitudes: a pilot study in the Australian Alps.

    PubMed

    Slaney, Graham; Cook, Angus; Weinstein, Philip

    2013-10-01

    Our hypothesis is that symptoms of high altitude syndromes are detectable even at intermediate altitudes, as commonly encountered under Australian conditions (<2500 m above sea level). High altitude medicine has long recognised several syndromes associated with rapid ascent to altitudes above 2500 m, including high altitude pulmonary oedema (HAPE), high altitude cerebral oedema (HACE) and high altitude flatus expulsion (HAFE). Symptoms of high altitude syndromes are of growing concern because of the global trend toward increasing numbers of tourists and workers exposed to both rapid ascent and sustained physical activity at high altitude. However, in Australia, high altitude medicine has almost no profile because of our relatively low altitudes by international standards. Three factors lead us to believe that altitude sickness in Australia deserves more serious consideration: Australia is subject to rapid growth in alpine recreational industries; altitude sickness is highly variable between individuals, and some people do experience symptoms already at 1500 m; and there is potential for an occupational health and safety issue amongst workers. To test this hypothesis we examined the relationship between any high altitude symptoms and a rapid ascent to an intermediate altitude (1800 m) by undertaking an intervention study in a cohort of eight medical clinic staff, conducted during July of the 2012 (Southern Hemisphere) ski season, using self-reporting questionnaires, at Mansfield (316 m above sea level) and at the Ski Resort of Mt Buller (1800 m), Victoria, Australia. The intervention consisted of ascent by car from Mansfield to Mt Buller (approx. 40 min drive). Participants completed a self-reporting questionnaire including demographic data and information on frequency of normal homeostatic processes (fluid intake and output, food intake and output, symptoms including thirst and headaches, and frequency of passing wind or urine). Data were recorded in hourly periods

  9. [Sildenafil and exercise performance at altitude].

    PubMed

    Peidro, Roberto M

    2015-01-01

    Barometric pressure and partial oxygen pressure decrease with increasing altitude. Hypobaric hypoxia produced is responsible for altitude-related diseases and it can cause severe decrements in exercise performance. The physiological adaptations to the altitude are multiple and they contribute to alter different athletic qualities. The VO2 worsening could be associated to increased pulmonary vascular resistance and nitric oxide diffusion alteration. Performance impairments at altitude can also be accentuated by hypoxia-induced elevations in pulmonary arterial pressure. Clinical studies have demonstrated the beneficial effects of sildenafil on the treatment of pulmonary hypertension. These effects have led to suggest that its indication for competitions at altitude might improve athletic performance. The investigations demonstrate different results depending on the altitude level and times and intensities of exercise. Some studies show performance improvements, although not in all participants. Individual responses vary widely between different athletes. This presentation examines the effects of altitude on exercise capacity and shows studies about the use of sildenafil to improve sport performance. This text also discusses the possible side effects and implications for the use of sildenafil in athletes, indication that is not the basic one of the drug. The physicians must know in each athlete the individual sildenafil side effects that could arise and that would influence negatively on health and performance. PMID:26339884

  10. Acclimatization and tolerance to extreme altitude

    NASA Technical Reports Server (NTRS)

    West, J. B.

    1993-01-01

    During the last ten years, two major experiments have elucidated the factors determining acclimatization and tolerance to extreme altitude (over 7000 m). These were the American Medical Research Expedition to Everest, and the low pressure chamber simulation, Operation Everest II. Extreme hyperventilation is one of the most important responses to extreme altitude. Its chief value is that it allows the climber to maintain an alveolar PO2 which keeps the arterial PO2 above dangerously low levels. Even so, there is evidence of residual impairment of central nervous system function after ascents to extreme altitude, and maximal oxygen consumption falls precipitously above 7000 m. The term 'acclimatization' is probably not appropriate for altitudes above 8000 m, because the body steadily deteriorates at these altitudes. Tolerance to extreme altitude is critically dependent on barometric pressure, and even seasonal changes in pressure probably affect climbing performance near the summit of Mt Everest. Supplementary oxygen always improves exercise tolerance at extreme altitudes, and rescue oxygen should be available on climbing expeditions to 8000 m peaks.

  11. Velocity gained and altitude lost in recoveries from inclined flight paths

    NASA Technical Reports Server (NTRS)

    Pearson, H A; Garvin, J B

    1941-01-01

    A series of charts is given showing the variation of the velocity gained and the altitude lost in dive pullouts with the initial indicated air speed and the dive angle. The effects of the maximum load factor, the drag parameter K, the initial altitude, and the type of recovery on the velocity gained and the altitude lost are also considered. The results were obtained from a step-by-step solution of the equations of motion in which mean values of the air density and the airplane drag coefficient were used. The load-factor variation with time is arbitrarily specified in various ways to simulate pull-out procedures, some of which might be encountered in flight.

  12. Cerebral blood flow at high altitude.

    PubMed

    Ainslie, Philip N; Subudhi, Andrew W

    2014-06-01

    This brief review traces the last 50 years of research related to cerebral blood flow (CBF) in humans exposed to high altitude. The increase in CBF within the first 12 hours at high altitude and its return to near sea level values after 3-5 days of acclimatization was first documented with use of the Kety-Schmidt technique in 1964. The degree of change in CBF at high altitude is influenced by many variables, including arterial oxygen and carbon dioxide tensions, oxygen content, cerebral spinal fluid pH, and hematocrit, but can be collectively summarized in terms of the relative strengths of four key integrated reflexes: 1) hypoxic cerebral vasodilatation; 2) hypocapnic cerebral vasoconstriction; 3) hypoxic ventilatory response; and 4) hypercapnic ventilatory response. Understanding the mechanisms underlying these reflexes and their interactions with one another is critical to advance our understanding of global and regional CBF regulation. Whether high altitude populations exhibit cerebrovascular adaptations to chronic levels of hypoxia or if changes in CBF are related to the development of acute mountain sickness are currently unknown; yet overall, the integrated CBF response to high altitude appears to be sufficient to meet the brain's large and consistent demand for oxygen. This short review is organized as follows: An historical overview of the earliest CBF measurements collected at high altitude introduces a summary of reported CBF changes at altitude over the last 50 years in both lowlanders and high-altitude natives. The most tenable candidate mechanism(s) regulating CBF at altitude are summarized with a focus on available data in humans, and a role for these mechanisms in the pathophysiology of AMS is considered. Finally, suggestions for future directions are provided. PMID:24971767

  13. High-Altitude Hydration System

    NASA Technical Reports Server (NTRS)

    Parazynski, Scott E.; Orndoff, Evelyne; Bue, Grant C.; Schaefbauer, Mark E.; Urban, Kase

    2010-01-01

    Three methods are being developed for keeping water from freezing during high-altitude climbs so that mountaineers can remain hydrated. Three strategies have been developed. At the time of this reporting two needed to be tested in the field and one was conceptual. The first method is Passive Thermal Control Using Aerogels. This involves mounting the fluid reservoir of the climber s canteen to an inner layer of clothing for better heat retention. For the field test, bottles were mounted to the inner fleece layer of clothing, and then aerogel insulation was placed on the outside of the bottle, and circumferentially around the drink straw. When climbers need to drink, they can pull up the insulated straw from underneath the down suit, take a sip, and then put it back into the relative warmth of the suit. For the field test, a data logger assessed the temperatures of the water reservoir, as well as near the tip of the drink straw. The second method is Passive Thermal Control with Copper-Shielded Drink Straw and Aerogels, also mounted to inner layers of clothing for better heat retention. Braided wire emanates from the inside of the fleece jacket layer, and continues up and around the drink straw in order to use body heat to keep the system-critical drink straw warm enough to keep water in the liquid state. For the field test, a data logger will be used to compare this with the above concept. The third, and still conceptual, method is Active Thermal Control with Microcontroller. If the above methods do not work, microcontrollers and tape heaters have been identified that could keep the drink straw warm even under extremely cold conditions. Power requirements are not yet determined because the thermal environment inside the down suit relative to the external environment has not been established. A data logger will be used to track both the external and internal temperatures of the suit on a summit day.

  14. [Human oxygen metabolism at high altitudes].

    PubMed

    Dabrowski, Wojciech; Dabrowski, Roman; Wyciszczok, Tomasz; Falk, Joanna

    2006-01-01

    The rapid tourism development resulted in higher incidence of the diseases related to oxygen metabolism pathologies at high altitudes. On the other hand, the lack of ability of close monitoring of changes during oxygen breathing in these conditions still makes it a subject of high interest for clinical studies. It seems that the main problem in oxygen metabolism at high altitudes is the disorder of pulmonary oxygen diffusion. In this paper the authors present the current knowledge, based on available literature, about the high-altitude oxygen metabolism. PMID:16813271

  15. Two tautomeric forms of 2-amino-5,6-dimethylpyrimidin-4-one.

    PubMed

    Hall, Victoria M; Bertke, Jeffery A; Swift, Jennifer A

    2016-06-01

    Derivatives of 4-hydroxypyrimidine are an important class of biomolecules. These compounds can undergo keto-enol tautomerization in solution, though a search of the Cambridge Structural Database shows a strong bias toward the 3H-keto tautomer in the solid state. Recrystallization of 2-amino-5,6-dimethyl-4-hydroxypyrimidine, C6H9N3O, from aqueous solution yielded triclinic crystals of the 1H-keto tautomer, denoted form (I). Though not apparent in the X-ray data, the IR spectrum suggests that small amounts of the 4-hydroxy tautomer are also present in the crystal. Monoclinic crystals of form (II), comprised of a 1:1 ratio of both the 1H-keto and the 3H-keto tautomers, were obtained from aqueous solutions containing uric acid. Forms (I) and (II) exhibit one-dimensional and three-dimensional hydrogen-bonding motifs, respectively. PMID:27256693

  16. Sequential Injection/Electrochemical Immunoassay for Quantifying the Pesticide Metabolite 3, 5, 6-Trichloro-2-Pyridinol

    SciTech Connect

    Liu, Guodong; Riechers, Shawn L.; Timchalk, Chuck; Lin, Yuehe

    2005-12-04

    An automated and sensitive sequential injection electrochemical immunoassay was developed to monitor a potential insecticide biomarker, 3, 5, 6-trichloro-2-pyridinol. The current method involved a sequential injection analysis (SIA) system equipped with a thin-layer electrochemical flow cell and permanent magnet, which was used to fix 3,5,6-trichloro-2-pyridinol (TCP) antibody coated magnetic beads (TCP-Ab-MBs) in the reaction zone. After competitive immunoreactions among TCP-Ab-MBs, TCP analyte, and horseradish peroxidase (HRP) labeled TCP, a 3, 3?, 5, 5?-tetramethylbenzidine dihydrochloride and hydrogen peroxide (TMB-H2O2) substrate solution was injected to produce an electroactive enzymatic product. The activity of HRP tracers was monitored by a square wave voltammetric scanning electroactive enzymatic product in the thin-layer flow cell. The voltammetric characteristics of the substrate and the enzymatic product were investigated under batch conditions, and the parameters of the immunoassay were optimized in the SIA system. Under the optimal conditions, the system was used to measure as low as 6 ng L-1 (ppt) TCP, which is around 50-fold lower than the value indicated by the manufacturer of the TCP RaPID Assay? kit (0.25 ug/L, colorimetric detection). The performance of the developed immunoassay system was successfully evaluated on tap water and river water samples spiked with TCP. This technique could be readily used for detecting other environmental contaminants by developing specific antibodies against contaminants and is expected to open new opportunities for environmental and biological monitoring.

  17. Field orientation effects during 5. 6-GHz radiofrequency irradiation of rats

    SciTech Connect

    Frei, M.R.; Jauchem, J.R.; Price, D.L.; Padilla, J.M. )

    1990-12-01

    Ketamine-anesthetized Sprague-Dawley rats were exposed in E and H orientations (long axis parallel to electric and magnetic fields, respectively) to far-field 5.6-GHz continuous-wave radio-frequency radiation (RFR). Power densities were used that resulted in equivalent whole-body average specific absorption rates of 14 W/kg in both orientations (90 mW/cm2 for E and 66 mW/cm2 for H). Irradiation was conducted to increase colonic temperature by 1 degree C (from 38.5 to 39.5 degrees C). During experimentation, arterial blood pressure and respiratory rate and colonic, tympanic, left and right subcutaneous (sides toward and away from RFR source), and tail temperatures were continuously recorded. Results showed no significant difference in the times required to cause a 1 degree C increase or to recover to the initial temperature when irradiation was stopped. Significant differences between E- and H-orientation exposure were seen in the patterns of localized heating. The tail and left subcutaneous temperature increases were significantly greater during E-orientation exposure, the tympanic site showed no difference, and the right subcutaneous temperature increase was significantly greater during H-orientation exposure. Under both exposure conditions, heart rate and mean arterial blood pressure significantly increased during irradiation; however, there were no significant differences between E and H orientation responses. These findings at 5.6 GHz are in contrast to the significant cardiovascular response differences between E- and H-orientation exposure noted during a previous study of irradiation at 2.45 GHz.

  18. Living altitude influences endurance exercise performance change over time at altitude.

    PubMed

    Chapman, Robert F; Karlsen, Trine; Ge, R-L; Stray-Gundersen, James; Levine, Benjamin D

    2016-05-15

    For sea level based endurance athletes who compete at low and moderate altitudes, adequate time for acclimatization to altitude can mitigate performance declines. We asked whether it is better for the acclimatizing athlete to live at the specific altitude of competition or at a higher altitude, perhaps for an increased rate of physiological adaptation. After 4 wk of supervised sea level training and testing, 48 collegiate distance runners (32 men, 16 women) were randomly assigned to one of four living altitudes (1,780, 2,085, 2,454, or 2,800 m) where they resided for 4 wk. Daily training for all subjects was completed at a common altitude from 1,250 to 3,000 m. Subjects completed 3,000-m performance trials on the track at sea level, 28 and 6 days before departure, and at 1,780 m on days 5, 12, 19, and 26 of the altitude camp. Groups living at 2,454 and 2,800 m had a significantly larger slowing of performance vs. the 1,780-m group on day 5 at altitude. The 1,780-m group showed no significant change in performance across the 26 days at altitude, while the groups living at 2,085, 2,454, and 2,800 m showed improvements in performance from day 5 to day 19 at altitude but no further improvement at day 26 The data suggest that an endurance athlete competing acutely at 1,780 m should live at the altitude of the competition and not higher. Living ∼300-1,000 m higher than the competition altitude, acute altitude performance may be significantly worse and may require up to 19 days of acclimatization to minimize performance decrements. PMID:26968028

  19. Risk assessment of high altitude free flight commercial aircraft operations

    SciTech Connect

    Kimura, C.Y.; Sandquist, G.M.; Slaughter, D.M.; Sanzo, D.L.

    1998-04-23

    A quantitative model is under development to assess the safety and efficiency of commercial aircraft operations under the Free Flight Program proposed for air traffic control for the US National Airspace System. The major objective of the Free Flight Program is to accommodate the dramatic growth anticipated in air traffic in the US. However, the potential impacts upon aircraft safety from implementing the Program have not been fully explored and evaluated. The model is directed at assessing aircraft operations at high altitude over the continental US airspace since this action is the initial step for Free Flight. Sequential steps with analysis, assessment, evaluation, and iteration will be required to satisfactorily accomplish the complete transition of US commercial aircraft traffic operations.

  20. Reliability and Validity of "Parents' Evaluation of Responsible Behaviors of 5-6 Year Old Children" Scale

    ERIC Educational Resources Information Center

    Polat, Ozgul; Dagal, Asude B.

    2013-01-01

    This study is aimed at developing a scale (Parents' Evaluation of Responsible Behaviors of 5-6 Year Old Children) for measuring parents' evaluation of their 5-6 year-old children's responsible behaviors. The construct validity of the scale was tested by Factor Analysis. Factor analysis determined that the scale can be clustered under 10 factors.…

  1. EVALUATION OF IMMUNOASSAY METHODS FOR DETERMINATION OF 3,5,6-TRICHLORO-2-PYRIDINOL IN MULTIPLE SAMPLE MEDIA

    EPA Science Inventory

    Two enzyme-linked immunosorbent assay (ELISA) methods were evaluated for the determination of 3,5,6-trichloro-2-pyridinol (3,5,6-TCP) in multiple sample media (dust, soil, food, and urine). The dust and soil samples were analyzed by the RaPID (TM) commercial immunoassay testing ...

  2. 17 CFR 5.6 - Maintenance of minimum financial requirements by retail foreign exchange dealers and futures...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... engaging in retail forex transactions. 5.6 Section 5.6 Commodity and Securities Exchanges COMMODITY FUTURES... forex transactions. (a) Each futures commission merchant offering or engaging in retail forex... engage in retail forex transactions and each person registered as a retail foreign exchange dealer or...

  3. 17 CFR 5.6 - Maintenance of minimum financial requirements by retail foreign exchange dealers and futures...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... engaging in retail forex transactions. 5.6 Section 5.6 Commodity and Securities Exchanges COMMODITY FUTURES... forex transactions. (a) Each futures commission merchant offering or engaging in retail forex... engage in retail forex transactions and each person registered as a retail foreign exchange dealer or...

  4. 17 CFR 5.6 - Maintenance of minimum financial requirements by retail foreign exchange dealers and futures...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... engaging in retail forex transactions. 5.6 Section 5.6 Commodity and Securities Exchanges COMMODITY FUTURES... forex transactions. (a) Each futures commission merchant offering or engaging in retail forex... engage in retail forex transactions and each person registered as a retail foreign exchange dealer or...

  5. 17 CFR 5.6 - Maintenance of minimum financial requirements by retail foreign exchange dealers and futures...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... engaging in retail forex transactions. 5.6 Section 5.6 Commodity and Securities Exchanges COMMODITY FUTURES... forex transactions. (a) Each futures commission merchant offering or engaging in retail forex... engage in retail forex transactions and each person registered as a retail foreign exchange dealer or...

  6. Altitude Testing of Large Liquid Propellant Engines

    NASA Technical Reports Server (NTRS)

    Maynard, Bryon; Raines, Nickey

    2008-01-01

    Altitude Testing of the J2-X engine at 100,000 feet (start capability). Chemical Steam Generation for providing vacuum. Project Started Mar 07. Test Stand Activation around Late 2010. J-2X Testing around early 2011.

  7. ALTITUDE AS A FACTOR IN AIR POLLUTION

    EPA Science Inventory

    Air pollution is affected by change in altitude. Cities with surface elevations above 1500 meters have atmospheric pressures which are approximately fifteen percent (15%) below pressures at sea level. Consequently, mobile sources designed to operate at pressures of one atmosphere...

  8. High-altitude cerebral oedema mimicking stroke.

    PubMed

    Yanamandra, Uday; Gupta, Amul; Patyal, Sagarika; Varma, Prem Prakash

    2014-01-01

    High-altitude cerebral oedema (HACO) is the most fatal high-altitude illness seen by rural physicians practising in high-altitude areas. HACO presents clinically with cerebellar ataxia, features of raised intracranial pressure (ICP) and coma. Early identification is important as delay in diagnosis can be fatal. We present two cases of HACO presenting with focal deficits mimicking stroke. The first patient presented with left-sided hemiplegia associated with the rapid deterioration in the sensorium. Neuroimaging revealed features suggestive of vasogenic oedema. The second patient presented with monoplegia of the lower limb. Neuroimaging revealed perfusion deficit in anterior cerebral artery territory. Both patients were managed with dexamethasone and they improved dramatically. Clinical picture and neuroimaging closely resembled acute ischaemic stroke in both cases. Thrombolysis in these patients would have been disastrous. Recent travel to high altitude, young age, absence of atherosclerotic risk factors and features of raised ICP concomitantly directed the diagnosis to HACO. PMID:24671373

  9. Paul Bikle's Record Altitude Sailplane Flight

    NASA Video Gallery

    On a cold and windy February afternoon 50 years ago, the late Paul Bikle, then director of NASA's Flight Research Center, soared into the stratosphere with one goal in mind - a world altitude recor...

  10. Aeronautic Instruments. Section II : Altitude Instruments

    NASA Technical Reports Server (NTRS)

    Mears, A H; Henrickson, H B; Brombacher, W G

    1923-01-01

    This report is Section two of a series of reports on aeronautic instruments (Technical Report nos. 125 to 132, inclusive). This section discusses briefly barometric altitude determinations, and describes in detail the principal types of altimeters and barographs used in aeronautics during the recent war. This is followed by a discussion of performance requirements for such instruments and an account of the methods of testing developed by the Bureau of Standards. The report concludes with a brief account of the results of recent investigations. For accurate measurements of altitude, reference must also be made to thermometer readings of atmospheric temperature, since the altitude is not fixed by atmospheric pressure alone. This matter is discussed in connection with barometric altitude determination.

  11. 77 FR 14269 - IFR Altitudes; Miscellaneous Amendments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ... ``significant rule'' under DOT Regulatory Policies and Procedures (44 ] FR 11034; February 26, 1979); and (3... Points From To MEA MAA Sec. 95.3000 Low Altitude RNAV Routes Sec. 95.3223 RNAV Route T223 Is Amended...

  12. Dual-bell altitude compensating nozzles

    NASA Technical Reports Server (NTRS)

    Horn, M.; Fisher, S.

    1993-01-01

    The primary objective of this cold flow test effort was to assess the performance characteristics of dual bell nozzles and to obtain preliminary design criteria by testing a number of configurations. Characteristics of interest included low altitude performance, high altitude performance, and the flow transition process. In combination with this performance data, other factors such as cost, weight, fabricability, and vehicle related issues could then be traded to establish the feasibility of the concept.

  13. Python Engine Installed in Altitude Wind Tunnel

    NASA Technical Reports Server (NTRS)

    1949-01-01

    An engine mechanic checks instrumentation prior to an investigation of engine operating characteristics and thrust control of a large turboprop engine with counter-rotating propellers under high-altitude flight conditions in the 20-foot-dianieter test section of the Altitude Wind Tunnel at the Lewis Flight Propulsion Laboratory of the National Advisory Committee for Aeronautics, Cleveland, Ohio, now known as the John H. Glenn Research Center at Lewis Field.

  14. Strand I: Physical Health. Sensory Perception. Health Curriculum Materials Grades 4, 5, 6.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Bureau of Elementary Curriculum Development.

    GRADES OR AGES: Grades 4, 5, and 6. SUBJECT MATTER: Sensory perceptions, the organs involved, and eye and hearing care. ORGANIZATION AND PHYSICAL APPEARANCE: The guide is divided into six different sectional steps organized around a gradual, ascending understanding of the sense organs. OBJECTIVES AND ACTIVITIES: The material is divided into…

  15. Sticky steps inhibit step motions near equilibrium

    NASA Astrophysics Data System (ADS)

    Akutsu, Noriko

    2012-12-01

    Using a Monte Carlo method on a lattice model of a vicinal surface with a point-contact-type step-step attraction, we show that, at low temperature and near equilibrium, there is an inhibition of the motion of macrosteps. This inhibition leads to a pinning of steps without defects, adsorbates, or impurities (self-pinning of steps). We show that this inhibition of the macrostep motion is caused by faceted steps, which are macrosteps that have a smooth side surface. The faceted steps result from discontinuities in the anisotropic surface tension (the surface free energy per area). The discontinuities are brought into the surface tension by the point-contact-type step-step attraction. The point-contact-type step-step attraction also originates “step droplets,” which are locally merged steps, at higher temperatures. We derive an analytic equation of the surface stiffness tensor for the vicinal surface around the (001) surface. Using the surface stiffness tensor, we show that step droplets roughen the vicinal surface. Contrary to what we expected, the step droplets slow down the step velocity due to the diminishment of kinks in the merged steps (smoothing of the merged steps).

  16. Child health and living at high altitude.

    PubMed

    Niermeyer, S; Andrade Mollinedo, P; Huicho, L

    2009-10-01

    The health of children born and living at high altitude is shaped not only by the low-oxygen environment, but also by population ancestry and sociocultural determinants. High altitude and the corresponding reduction in oxygen delivery during pregnancy result in lower birth weight with higher elevation. Children living at high elevations are at special risk for hypoxaemia during infancy and during acute lower respiratory infection, symptomatic high-altitude pulmonary hypertension, persistence of fetal vascular connections, and re-entry high-altitude pulmonary oedema. However, child health varies from one population group to another due to genetic adaptation as well as factors such as nutrition, intercurrent infection, exposure to pollutants and toxins, socioeconomic status, and access to medical care. Awareness of the risks uniquely associated with living at high altitude and monitoring of key health indicators can help protect the health of children at high altitude. These considerations should be incorporated into the scaling-up of effective interventions for improving global child health and survival. PMID:19066173

  17. Nasal peak inspiratory flow at altitude.

    PubMed

    Barry, P W; Mason, N P; Richalet, J P

    2002-01-01

    The present study investigated whether there are changes in nasal peak inspiratory flow (NPIF) during hypobaric hypoxia under controlled environmental conditions. During operation Everest III (COMEX '97), eight subjects ascended to a simulated altitude of 8,848 m in a hypobaric chamber. NPIF was recorded at simulated altitudes of 0 m, 5,000 m and 8,000 m. Oral peak inspiratory and expiratory flow (OPIF, OPEF) were also measured. Ambient air temperature and humidity were controlled. NPIF increased by a mean +/- SD of 16 +/- 12% from sea level to 8,000 m, whereas OPIF increased by 47 +/- 14%. NPIF rose by 0.085 +/- 0.03 L x s(-1) per kilometre of ascent (p<0.05), significantly less than the rise in OPIF and OPEF of 0.35 +/- 0.10 and 0.33 +/- 0.04 L x s(-1) per kilometre (p<0.0005). Nasal peak inspiratory flow rises with ascent to altitude. The rise in nasal peak inspiratory flow with altitude was far less than oral peak inspiratory flow and less than the predicted rise according to changes in air density. This suggests flow limitation at the nose, and occurs under controlled environmental conditions, refuting the hypothesis that nasal blockage at altitude is due to the inhalation of cold, dry air. Further work is needed to determine if nasal blockage limits activity at altitude. PMID:11843316

  18. Cabin cruising altitudes for regular transport aircraft.

    PubMed

    2008-04-01

    The adverse physiological effects of flight, caused by ascent to altitude and its associated reduction in barometric pressure, have been known since the first manned balloon flights in the 19th century. It soon became apparent that the way to protect the occupant of an aircraft from the effects of ascent to altitude was to enclose either the individual, or the cabin, in a sealed or pressurized environment. Of primary concern in commercial airline transport operations is the selection of a suitable cabin pressurization schedule that assures adequate oxygen partial pressures for all intended occupants. For the past several decades, 8000 ft has been accepted as the maximum operational cabin pressure altitude in the airline industry. More recent research findings on the physiological and psycho-physiological effects of mild hypoxia have provided cause for renewed discussion of the "acceptability" of a maximum cabin cruise altitude of 8000 ft; however, we did not find sufficient scientific data to recommend a change in the cabin altitude of transport category aircraft. The Aerospace Medical Association (AsMA) should support further research to evaluate the safety, performance and comfort of occupants at altitudes between 5000 and 10,000 ft. PMID:18457303

  19. Early history of high-altitude physiology.

    PubMed

    West, John B

    2016-02-01

    High-altitude physiology can be said to have begun in 1644 when Torricelli described the first mercury barometer and wrote the immortal words "We live submerged at the bottom of an ocean of the element air." Interestingly, the notion of atmospheric pressure had eluded his teacher, the great Galileo. Blaise Pascal was responsible for describing the fall in pressure with increasing altitude, and Otto von Guericke gave a dramatic demonstration of the enormous force that could be developed by atmospheric pressure. Robert Boyle learned of Guericke's experiment and, with Robert Hooke, constructed the first air pump that allowed small animals to be exposed to a low pressure. Hooke also constructed a small low-pressure chamber and exposed himself to a simulated altitude of about 2400 meters. With the advent of ballooning, humans were rapidly exposed to very low pressures, sometimes with tragic results. For example, the French balloon, Zénith, rose to over 8000 m, and two of the three aeronauts succumbed to the hypoxia. Paul Bert was the first person to clearly state that the deleterious effects of high altitude were caused by the low partial pressure of oxygen (PO2), and later research was accelerated by high-altitude stations and expeditions to high altitude. PMID:25762218

  20. Comparing earthquake models for the Corinth rift for Mw>=5.5/6/6.5 (Greece)

    NASA Astrophysics Data System (ADS)

    Boiselet, Aurélien; Scotti, Oona; Lyon-Caen, Hélène; Ford, Mary; Meyer, NIcolas; Bernard, Pascal

    2013-04-01

    The Corinth rift (Greece) is identified as a site of major importance for earthquake studies in Europe, producing one of the highest seismic activity and strain in the Euro-Mediterranean region. It is characterized by an asymmetrical structure, with the most active normal faults dipping north and a north-south extension rate measured by GPS increasing from 0.6 mm/year in the eastern part of the rift to 15 mm/year in the western part. Frequent seismic swarms and destructive earthquakes are observed in this area. The Corinth rift Laboratory (CRL, http://crlab.eu) european project investigates fault mechanics, its relationship with earthquakes, fluid flow and the related hazards in the western part of the rift, covering an area about 50 km by 40 km, between the city of Patras to the west and the city of Aigion to the east. As part of this project, within the CRL-SISCOR group, we construct earthquake forecast models (EFM) for M>=5.5/6/6.5 events of the Corinth rift area based on the in-depth seismotectonic studies available for this region. We first present the methodology used to construct the earthquake and fault databases and to quantify the associated uncertainties. We then propose EFM following two approaches: one based on the definition of seimotectonic areas with similar geologic or strain characteristics, the second one based on the definition of fault sources mapped at the surface as well as blind ones. In order to compute the probability of occurrence for M>=5.5/6/6.5 for seismotectonic areas, we analyse two earthquake catalogues available for Greece (National Observatory of Athens, Thessaloniki), apply two declustering methods (Reasenberg and Gardner) to construct a Poissonian earthquake catalogue and test the influence of the minimal magnitude (3.5; 4.0). We compare the impact of maximum magnitude and corner magnitude (Kagan 1997, 2002) estimations. We then apply the Weichert method to estimate the probability of occurrence of M>=5.5/6/6.5 based on

  1. Elevated plasma atrial natriuretic factor and vasopressin in high-altitude pulmonary edema.

    PubMed

    Cosby, R L; Sophocles, A M; Durr, J A; Perrinjaquet, C L; Yee, B; Schrier, R W

    1988-11-15

    A diagnosis of acute high-altitude pulmonary edema was made in five male skiers (age, 35.0 +/- 1.8 years) by history and physical examination and was confirmed by a characteristic chest radiogram showing alveolar infiltrates associated with a normal cardiac silhouette. Five healthy age- and sex-matched subjects with similar physical activity at the same altitude served as controls. Plasma sodium was 135.0 +/- 1.5 mmol/L in the acutely ill patients compared with 144.0 +/- 3.3 mmol/L in the controls (P less than 0.025). Mean plasma atrial natriuretic factor immunoreactivity averaged 17.6 +/- 5.6 pmol/L in patients with high-altitude pulmonary edema compared with 6.8 +/- 0.7 pmol/L in the controls at the same altitude (P less than 0.05). Elevated atrial natriuretic factor levels normalized to 7.5 +/- 1.9 pmol/L (P less than 0.05) during recovery in Denver (altitude, 1600 meters) 24 hours later. Plasma arginine vasopressin levels were 1.8 +/- 0.37 pmol/L in patients with high-altitude pulmonary edema at diagnosis compared with 0.92 +/- 0.28 pmol/L in controls (P = 0.07). The inappropriately elevated arginine vasopressin levels decreased to 1.29 +/- 0.37 pmol/L during recovery (P less than 0.025), but the lowered plasma sodium concentration had not normalized by discharge within 24-hours of transfer to Denver and averaged 135.8 +/- 1.2 mmol/L. The pathophysiologic implications of these findings are discussed. PMID:2973274

  2. Essential Roles of the Smc5/6 Complex in Replication through Natural Pausing Sites and Endogenous DNA Damage Tolerance.

    PubMed

    Menolfi, Demis; Delamarre, Axel; Lengronne, Armelle; Pasero, Philippe; Branzei, Dana

    2015-12-17

    The essential functions of the conserved Smc5/6 complex remain elusive. To uncover its roles in genome maintenance, we established Saccharomyces cerevisiae cell-cycle-regulated alleles that enable restriction of Smc5/6 components to S or G2/M. Unexpectedly, the essential functions of Smc5/6 segregated fully and selectively to G2/M. Genetic screens that became possible with generated alleles identified processes that crucially rely on Smc5/6 specifically in G2/M: metabolism of DNA recombination structures triggered by endogenous replication stress, and replication through natural pausing sites located in late-replicating regions. In the first process, Smc5/6 modulates remodeling of recombination intermediates, cooperating with dissolution activities. In the second, Smc5/6 prevents chromosome fragility and toxic recombination instigated by prolonged pausing and the fork protection complex, Tof1-Csm3. Our results thus dissect Smc5/6 essential roles and reveal that combined defects in DNA damage tolerance and pausing site-replication cause recombination-mediated DNA lesions, which we propose to drive developmental and cancer-prone disorders. PMID:26698660

  3. Smc5/6 Coordinates Formation and Resolution of Joint Molecules with Chromosome Morphology to Ensure Meiotic Divisions

    PubMed Central

    Blitzblau, Hannah G.; Newcombe, Sonya; Chan, Andrew Chi-ho; Newnham, Louise; Li, Zhaobo; Gray, Stephen; Herbert, Alex D.; Arumugam, Prakash; Hochwagen, Andreas; Hunter, Neil; Hoffmann, Eva

    2013-01-01

    During meiosis, Structural Maintenance of Chromosome (SMC) complexes underpin two fundamental features of meiosis: homologous recombination and chromosome segregation. While meiotic functions of the cohesin and condensin complexes have been delineated, the role of the third SMC complex, Smc5/6, remains enigmatic. Here we identify specific, essential meiotic functions for the Smc5/6 complex in homologous recombination and the regulation of cohesin. We show that Smc5/6 is enriched at centromeres and cohesin-association sites where it regulates sister-chromatid cohesion and the timely removal of cohesin from chromosomal arms, respectively. Smc5/6 also localizes to recombination hotspots, where it promotes normal formation and resolution of a subset of joint-molecule intermediates. In this regard, Smc5/6 functions independently of the major crossover pathway defined by the MutLγ complex. Furthermore, we show that Smc5/6 is required for stable chromosomal localization of the XPF-family endonuclease, Mus81-Mms4Eme1. Our data suggest that the Smc5/6 complex is required for specific recombination and chromosomal processes throughout meiosis and that in its absence, attempts at cell division with unresolved joint molecules and residual cohesin lead to severe recombination-induced meiotic catastrophe. PMID:24385939

  4. Regulation of Ins(3,4,5,6)P(4) signaling by a reversible kinase/phosphatase.

    PubMed

    Ho, Melisa W Y; Yang, Xiaonian; Carew, Mark A; Zhang, Tong; Hua, Len; Kwon, Yong-Uk; Chung, Sung-Kee; Adelt, Stephan; Vogel, Günter; Riley, Andrew M; Potter, Barry V L; Shears, Stephen B

    2002-03-19

    Regulation of Cl(-) channel conductance by Ins(3,4,5,6)P(4) provides receptor-dependent control over salt and fluid secretion, cell volume homeostasis, and electrical excitability of neurones and smooth muscle. Ignorance of how Ins(3,4,5,6)P(4) is synthesized has long hindered our understanding of this signaling pathway. We now show Ins(3,4,5,6)P(4) synthesis by Ins(1,3,4,5,6)P(5) 1-phosphatase activity by an enzyme previously characterized as an Ins(3,4,5,6)P(4) 1-kinase. Rationalization of these phenomena with a ligand binding model unveils Ins(1,3,4)P(3) as not simply an alternative kinase substrate, but also an activator of Ins(1,3,4,5,6)P(5) 1-phosphatase. Stable overexpression of the enzyme in epithelial monolayers verifies its physiological role in elevating Ins(3,4,5,6)P(4) levels and inhibiting secretion. It is exceptional for a single enzyme to catalyze two opposing signaling reactions (1-kinase/1-phosphatase) under physiological conditions. Reciprocal coordination of these opposing reactions offers an alternative to general doctrine that intracellular signals are regulated by integrating multiple, distinct phosphatases and kinases. PMID:11909533

  5. Smc5/6 Is a Telomere-Associated Complex that Regulates Sir4 Binding and TPE

    PubMed Central

    Chartrand, Pascal; Cobb, Jennifer A.

    2016-01-01

    SMC proteins constitute the core members of the Smc5/6, cohesin and condensin complexes. We demonstrate that Smc5/6 is present at telomeres throughout the cell cycle and its association with chromosome ends is dependent on Nse3, a subcomponent of the complex. Cells harboring a temperature sensitive mutant, nse3-1, are defective in Smc5/6 localization to telomeres and have slightly shorter telomeres. Nse3 interacts physically and genetically with two Rap1-binding factors, Rif2 and Sir4. Reduction in telomere-associated Smc5/6 leads to defects in telomere clustering, dispersion of the silencing factor, Sir4, and a loss in transcriptional repression for sub-telomeric genes and non-coding telomeric repeat-containing RNA (TERRA). SIR4 recovery at telomeres is reduced in cells lacking Smc5/6 functionality and vice versa. However, nse3-1/ sir4 Δ double mutants show additive defects for telomere shortening and TPE indicating the contribution of Smc5/6 to telomere homeostasis is only in partial overlap with SIR factor silencing. These findings support a role for Smc5/6 in telomere maintenance that is separate from its canonical role(s) in HR-mediated events during replication and telomere elongation. PMID:27564449

  6. Smc5/6 Is a Telomere-Associated Complex that Regulates Sir4 Binding and TPE.

    PubMed

    Moradi-Fard, Sarah; Sarthi, Jessica; Tittel-Elmer, Mireille; Lalonde, Maxime; Cusanelli, Emilio; Chartrand, Pascal; Cobb, Jennifer A

    2016-08-01

    SMC proteins constitute the core members of the Smc5/6, cohesin and condensin complexes. We demonstrate that Smc5/6 is present at telomeres throughout the cell cycle and its association with chromosome ends is dependent on Nse3, a subcomponent of the complex. Cells harboring a temperature sensitive mutant, nse3-1, are defective in Smc5/6 localization to telomeres and have slightly shorter telomeres. Nse3 interacts physically and genetically with two Rap1-binding factors, Rif2 and Sir4. Reduction in telomere-associated Smc5/6 leads to defects in telomere clustering, dispersion of the silencing factor, Sir4, and a loss in transcriptional repression for sub-telomeric genes and non-coding telomeric repeat-containing RNA (TERRA). SIR4 recovery at telomeres is reduced in cells lacking Smc5/6 functionality and vice versa. However, nse3-1/ sir4 Δ double mutants show additive defects for telomere shortening and TPE indicating the contribution of Smc5/6 to telomere homeostasis is only in partial overlap with SIR factor silencing. These findings support a role for Smc5/6 in telomere maintenance that is separate from its canonical role(s) in HR-mediated events during replication and telomere elongation. PMID:27564449

  7. Reactions of organyl and silyl alanes with 1,3,4,5,6-pentamethyl-2-aminoborazine.

    PubMed

    Fan, Maomin; Duesler, Eileen N; Nöth, Heinrich; Paine, Robert T

    2010-03-15

    The reactions of (Me(3)Si)(3)Al, Me(3)Al, Et(3)Al, and i-Bu(3)Al with 1,3,4,5,6-pentamethyl-2-aminoborazine have been examined. An amine alane adduct (Me(3)Si)(3)Al.NH(2)B(3)(Me)(2)N(3)Me(3) (1) and several elimination products [(Me(3)Si)(2)AlN(H)B(3)(Me)(2)N(3)Me(3)](2) (2), [(Me(3)SiAl)(4)(Me(3)SiN)(3)NH] (3), [Me(2)AlN(H) B(3)(Me)(2)N(3)Me(3)](2) (4), [Et(2)AlN(H) B(3)(Me)(2)N(3)Me(3)](2) (5), and [i-Bu(2)AlN(H) B(3)(Me)(2)N(3)Me(3)](2) (6) have been isolated. Compounds 1, 2, 4-6 have been spectroscopically characterized, and single crystal X-ray diffraction structure determinations have been completed for 1-4 and 6. The molecular chemistry provides insight into the reaction of Me(3)Al and 1,3,5-N-trimethyl-2,4,6-B-triaminoborazine that, upon pyrolysis, produces AlN/BN composite ceramic materials. PMID:20158196

  8. Brazilian Red Propolis Attenuates Hypertension and Renal Damage in 5/6 Renal Ablation Model

    PubMed Central

    Teles, Flávio; da Silva, Tarcilo Machado; da Cruz Júnior, Francisco Pessoa; Honorato, Vitor Hugo; de Oliveira Costa, Henrique; Barbosa, Ana Paula Fernandes; de Oliveira, Sabrina Gomes; Porfírio, Zenaldo; Libório, Alexandre Braga; Borges, Raquel Lerner; Fanelli, Camilla

    2015-01-01

    The pathogenic role of inflammation and oxidative stress in chronic kidney disease (CKD) is well known. Anti-inflammatories and antioxidant drugs has demonstrated significant renoprotection in experimental nephropathies. Moreover, the inclusion of natural antioxidants derived from food and herbal extracts (such as polyphenols, curcumin and lycopene) as an adjuvant therapy for slowing CKD progression has been largely tested. Brazilian propolis is a honeybee product, whose anti-inflammatory, antimicrobial and antioxidant effects have been widely shown in models of sepsis, cancer, skin irritation and liver fibrosis. Furthermore, previous studies demonstrated that this compound promotes vasodilation and reduces hypertension. However, potential renoprotective effects of propolis in CKD have never been investigated. The aim of this study was to evaluate the effects of a subtype of Brazilian propolis, the Red Propolis (RP), in the 5/6 renal ablation model (Nx). Adult male Wistar rats underwent Nx and were divided into untreated (Nx) and RP-treated (Nx+RP) groups, after 30 days of surgery; when rats already exhibited marked hypertension and proteinuria. Animals were observed for 90 days from the surgery day, when Nx+RP group showed significant reduction of hypertension, proteinuria, serum creatinine retention, glomerulosclerosis, renal macrophage infiltration and oxidative stress, compared to age-matched untreated Nx rats, which worsened progressively over time. In conclusion, RP treatment attenuated hypertension and structural renal damage in Nx model. Reduction of renal inflammation and oxidative stress could be a plausible mechanism to explain this renoprotection. PMID:25607548

  9. Intracellular localization of human Ins(1,3,4,5,6)P5 2-kinase

    PubMed Central

    Brehm, Maria A.; Schenk, Tobias M. H.; Zhou, Xuefei; Fanick, Werner; Lin, Hongying; Windhorst, Sabine; Nalaskowski, Marcus M.; Kobras, Mario; Shears, Stephen B.; Mayr, Georg W.

    2007-01-01

    InsP6 is an intracellular signal with several proposed functions that is synthesized by IP5K [Ins(1,3,4,5,6)P5 2-kinase]. In the present study, we overexpressed EGFP (enhanced green fluorescent protein)–IP5K fusion proteins in NRK (normal rat kidney), COS7 and H1299 cells. The results indicate that there is spatial microheterogeneity in the intracellular localization of IP5K that could also be confirmed for the endogenous enzyme. This may facilitate changes in InsP6 levels at its sites of action. For example, overexpressed IP5K showed a structured organization within the nucleus. The kinase was preferentially localized in euchromatin and nucleoli, and co-localized with mRNA. In the cytoplasm, the overexpressed IP5K showed locally high concentrations in discrete foci. The latter were attributed to stress granules by using mRNA, PABP [poly(A)-binding protein] and TIAR (TIA-1-related protein) as markers. The incidence of stress granules, in which IP5K remained highly concentrated, was further increased by puromycin treatment. Using FRAP (fluorescence recovery after photobleaching) we established that IP5K was actively transported into the nucleus. By site-directed mutagenesis we identified a nuclear import signal and a peptide segment mediating the nuclear export of IP5K. PMID:17705785

  10. DNA binding studies of 3, 5, 6-trichloro-2-pyridinol pesticide metabolite.

    PubMed

    Kashanian, Soheila; Shariati, Zohreh; Roshanfekr, Hamideh; Ghobadi, Sirous

    2012-07-01

    3, 5, 6-Trichloro-2-pyridinol (TCP) is a stable metabolite of two major pesticides, Chlopyrifos insecticide and Triclopyr herbicide, which are widely used in the world. The potential health hazard associated with TCP is identified due to its high affinity to the DNA molecule. Therefore, in this study, the interaction of native calf thymus DNA with TCP has been investigated using spectrophotometric, circular dichroism (CD), spectrofluorometric, viscometric and voltametric techniques. It was found that TCP molecules could interact with DNA via a groove-binding mode, as evidenced by hyperchromism, with no red shift in the UV absorption band of TCP, no changes in K(b) values in the presence of salt, no significant changes in the specific viscosity and CD spectra of DNA, and a decrease in peak currents with no shift in the voltamogram. In addition, TCP is able to release Hoechst 33258, a strong groove binder, in the DNA solutions. The results are indicative of the groove-binding mode of TCP to DNA. PMID:22519761

  11. Fe L-shell lines from n (n=4, 5, 6) to 2 transitions

    NASA Astrophysics Data System (ADS)

    Chen, H.; Beiersdorfer, P.; Brown, G.; Behar, E.

    2003-03-01

    Fe L-shell emission lines at wavelengths less than 10 angstroms come from n (n great than 3) to 2 transitions. These lines embed information such as electron density and temperature that is of fundamental importance to understanding the physics of astrophysical objects. Unresolved by previous x-ray observatories, these low wavelength Fe lines are clearly observable by Chandra and XMM x-ray satellites. To meet the needs of using these lines as diagnostics, we have studied the n to 2 transitions (n = 4, 5, 6) Fe L-shell lines using the atomic codes HULLAC and FAC. Using the LLNL electron beam ion trap, we also made laboratory measurements for this wavelength region, following the success of our Fe L-shell emission lines for the 3-2 transitions (Brown et al, APJ supp. 2002). Our measurements and their comparison with code simulations will be reported, together with a discussion of the possible use of these low wavelength lines as diagnostics for astrophysics. This work was performed under the auspices of the U.S. DOE by LLNL under contract No. W-7405-Eng-48 and supported by NASA SARA grants to LLNL, GSFC, and Columbia University.

  12. Endothelial cell transfusion ameliorates endothelial dysfunction in 5/6 nephrectomized rats

    PubMed Central

    Pacurari, Maricica; Xing, Dongqi; Hilgers, Rob H. P.; Guo, Yuan Yuan; Yang, Zhengqin

    2013-01-01

    Endothelial dysfunction is prevalent in chronic kidney disease. This study tested the hypothesis that transfusion of rat aortic endothelial cells (ECs) ameliorates endothelial dysfunction in a rat model of chronic kidney disease. Male Sprague-Dawley rats underwent sham surgery or 5/6 nephrectomy (Nx). Five weeks after Nx, EC (1.5 × 106 cells/rat) or vehicle were transfused intravenously. One week later, vascular reactivity of mesenteric artery was assessed on a wire myograph. Sensitivity of endothelium-dependent relaxation to acetylcholine and maximum vasodilation were impaired by Nx and improved by EC transfusion. Using selective pharmacological nitric oxide synthase isoform inhibitors, we demonstrated that the negative effect of Nx on endothelial function and rescue by EC transfusion are, at least in part, endothelial nitric oxide synthase mediated. Plasma asymmetric dimethylarginine was increased by Nx and decreased by EC transfusion, whereas mRNA expression of dimethylarginine dimethylaminohydrolases 1 (DDAH1) was decreased by Nx and restored by EC transfusion. Immunohistochemical staining confirmed that local expression of DDAH1 is decreased by Nx and increased by EC transfusion. In conclusion, EC transfusion attenuates Nx-induced endothelium-dependent vascular dysfunction by regulating DDAH1 expression and enhancing endothelial nitric oxide synthase activity. These results suggest that EC-based therapy could provide a novel therapeutic strategy to improve vascular function in chronic kidney disease. PMID:23955716

  13. Nitric oxide in adaptation to altitude

    PubMed Central

    Laskowski, Daniel; Erzurum, Serpil C.

    2012-01-01

    This review summarizes published information on levels of nitric oxide gas (NO) in the lungs and NO-derived liquid phase molecules in the acclimatization of visitors newly arrived at altitudes of 2500m or more and adaptation of populations whose ancestors arrived thousands of years ago. Studies of acutely exposed visitors to high altitude focus on the first 24–48 hours with just a few extending to days or weeks. Among healthy visitors, NO levels in the lung, plasma and/or red blood cells fell within three hours, but then returned toward baseline or slightly higher by 48 hours, and increased above baseline by 5 days. Among visitors ill with high-altitude pulmonary edema at the time of the study or in the past, NO levels were lower than their healthy counterparts. As for highland populations, Tibetans had NO levels in the lung, plasma and red blood cells that were at least double and in some cases orders of magnitude greater than other populations regardless of altitude. Red blood cell associated nitrogen oxides were more than two hundred times higher. Other highland populations had generally higher levels although not to the degree showed by Tibetans. Overall, responses of those acclimatized and those presumed to be adapted are in the same direction although the Tibetans have much larger responses. Missing are long-term data on lowlanders at altitude showing how similar they become to the Tibetan phenotype. Also missing are data on Tibetans at low altitude to see the extent to which their phenotype is a response to the immediate environment or expressed constitutively. The mechanisms causing the visitors’ and the Tibetans’ high levels of NO and NO-derived molecules at altitude remain unknown. Limited data suggest processes including hypoxic upregulation of NO synthase gene expression, hemoglobin-NO reactions and genetic variation. Gains in understanding will require integrating appropriate methods and measurement techniques with indicators of adaptive function

  14. Neutral Wind Observations below 200 km altitudes

    NASA Astrophysics Data System (ADS)

    Watanabe, S.; Abe, T.; Habu, H.; Kakinami, Y.; Larsen, M. F.; Pfaff, R. F., Jr.; Yamamoto, M.

    2015-12-01

    Neutral Wind Observations below 200 km altitudesS. Watanabe1, T. Abe2, H. Habu2, Y. Kakinami3, M. Larsen4, R. Pfaff5, M. Yamamoto6, M-Y. Yamamoto31Hokkaido University/Hokkaido Information University, 2JAXA/ISAS, 3Kochi University of Technology, 4Clemson University, 5NASA/Goddard Space Flight Center, 6Kyoto University, Neutral wind in the thermosphere is one of the key parameters to understand the ionosphere-thermosphere coupling process. JAXA/ISAS successfully launched sounding rockets from Uchinoura Space Center (USC) on September 2, 2007, January 12, 2012, and July 20, 2013, and NASA launched sounding rockets from Kwajalein on May 7, 2013 and from Wallops on July 4, 2013. The rockets installed Lithium and/or TMA canisters as well as instruments for plasma and electric and magnetic fields. The atomic Lithium gases were released at altitudes between 150 km and 300 km in the evening on September 2, 2007, at altitude of ~100 km in the morning on January 12, 2012, at altitude of ~120km in the midnight on July 20, 2013, at altitude between 150 km and 300 km in the evening on May 7, 2013 and at altitude of ~150 km in the noon on July 4, 2013. The Lithium atoms were scattering sunlight by resonance scattering with wavelength of 670nm. However, the Lithium atoms scattered moon light on July 20, 2013. The moon light scattering is the first time to use for thermospheric wind measurement in the midnight. The Lithium clouds/trails and TMA trails showed clearly the neutral wind shears and atmospheric waves at ~150 km altitude in the lower thermosphere for all local time.

  15. High antiallergic activity of 5,6,4'-trihydroxy-7,8,3'-trimethoxyflavone and 5,6-dihydroxy-7,8,3',4'-tetramethoxyflavone from eau de cologne mint (Mentha×piperita citrata).

    PubMed

    Sato, Akihiko; Tamura, Hirotoshi

    2015-04-01

    The following compounds with higher antiallergic activities were isolated from eau de cologne mint leaves: 5,6,4'-trihydroxy-7,8-dimethoxyflavone (6), 5,6,4'-trihydroxy-7,8,3'-trimethoxyflavone (7), 5,6-dihydroxy-7,3',4'-trimethoxyflavone (8), 5,6-dihydroxy-7,8,3',4'-tetramethoxyflavone (9), and 5,6-dihydroxy-7,8,4'-trimethoxyflavone (10). The IC50 values of compounds 6-10 against RBL-2H3 cells were 6.7, 2.4, 5.6, 3.0, and 6.1μM. Compounds 7 and 9 (IC50 2.4μM and 3.0μM) had the highest antiallergic activities among the flavonoids previously reported. The amounts of 7, 9, and 10 isolated were fairly high, at 177.7mg/kg, 278.0mg/kg, and 179.7mg/kg in the mint, respectively. LD5 value (index of toxicity) and LD5/IC50 ratio of 7 and 9 indicate that the safety is greater than that of luteolin, a typical antiallergic substance. The extract containing powerful antiallergic flavones, 6-10 with higher hydrophobicity could be selectively separated from the extract containing luteolin and other flavonoid glycosides by partition with dichloromethane and water. Therefore, compounds 7 and 9 in mint, and the dichloromethane extract would be the most potent and preventive resources against type I allergy. PMID:25704366

  16. Decadally resolved quantitative temperature reconstruction spanning 5.6 ka at Kurupa Lake, Arctic Alaska

    NASA Astrophysics Data System (ADS)

    Boldt, B. R.; Kaufman, D. S.; Briner, J. P.

    2012-12-01

    Pre-instrumental quantitative temperature records, fundamental for placing recent warming in the context of long-term, natural climate variability, are scarce in Arctic Alaska. New non-destructive high-resolution core scanning methods provide a means of constructing downcore inference models for various paleoclimate signals. Here we use visible reflectance spectroscopy (VIS-RS) to measure organic pigment (chlorophyll derivative) concentration in sediments from Kurupa Lake to quantitatively reconstruct air temperature in the north-central Brooks Range, Alaska during the past 5.6 ka. Kurupa Lake (N 68.35°, W -154.61°) is 29.7 km2, 40 m at maximum depth, and is fed by several tributaries, including meltwater from eight rapidly disappearing cirque glaciers. A 6.2-m-long core composed of finely laminated (sub-mm to 5 cm) coarse-grained clays to medium-grained silts was collected in 2010 from the primary depocenter of Kurupa Lake (depth = 34 m). The age model for the core is based on six radiocarbon ages and a Pu profile to capture the 1963 spike and 1953 onset of Pu deposition from atmospheric weapons testing. The split-core face was scanned with a Konica Minolta CM-2600d spectrometer at 2 mm intervals, corresponding to 1-2 years. The relative absorption band depth at 660-670 nm (RABD660-670) was used to quantify total sedimentary organic pigments (primarily diagenetic products of chlorophyll-a) as a proxy for primary productivity. Gridded temperature data from the NCEP reanalysis dataset were used for this study because regional weather stations in the Brooks Range are scarce and records discontinuous. The gridded data perform well in this area and are highly correlated (r = 0.88) with the instrumental record from Barrow. Mean May-through-October (warm half-year) temperature (5-year smoothed) from NCEP reanalysis data (130 years) correlates with inferred organic pigment content from Kurupa Lake (r = 0.76, p < 0.001). We chose k-fold cross-validation (k = 10) to

  17. Advanced Gas Reactor (AGR)-5/6/7 Fuel Irradiation Experiments in the Advanced Test Reactor

    SciTech Connect

    A. Joseph Palmer; David A. Petti; S. Blaine Grover

    2014-04-01

    The United States Department of Energy’s Very High Temperature Reactor (VHTR) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating up to seven separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which each consist of at least five separate capsules, are being irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gases also have on-line fission product monitoring the effluent from each capsule to track performance of the fuel during irradiation. The first two experiments (designated AGR-1 and AGR-2), have been completed. The third and fourth experiments have been combined into a single experiment designated AGR-3/4, which started its irradiation in December 2011 and is currently scheduled to be completed in April 2014. The design of the fuel qualification experiment, designated AGR-5/6/7, is well underway and incorporates lessons learned from the three previous experiments. Various design issues will be discussed with particular details related to selection of thermometry.

  18. HIGH ALTITUDE TESTING OF RESIDENTIAL WOOD-FIRED COMBUSTION EQUIPMENT

    EPA Science Inventory

    To determine whether emissions from operating a wood stove at high altitude differ from those at low altitude, a high altitude sampling program was conducted which was compared to previously collected low altitude data. Emission tests were conducted in the identical model stove u...

  19. Wind study for high altitude platform design

    NASA Technical Reports Server (NTRS)

    Strganac, T. W.

    1979-01-01

    An analysis of upper air winds was performed to define the wind environment at potential operating altitudes for high-altitude powered platform concepts. Expected wind conditions of the contiguous United States, Pacific area (Alaska to Sea of Japan), and European area (Norwegian and Mediterranean Seas) were obtained using a representative network of sites selected based upon adequate high-altitude sampling, geographic dispersion, and observed upper wind patterns. A data base of twenty plus years of rawinsonde gathered wind information was used in the analysis. Annual variations from surface to 10 mb (approximately 31 km) pressure altitude were investigated to encompass the practical operating range for the platform concepts. Parametric analysis for the United States and foreign areas was performed to provide a basis for vehicle system design tradeoffs. This analysis of wind magnitudes indicates the feasibility of annual operation at a majority of sites and more selective seasonal operation for the extreme conditions between the pressure altitudes of 100 to 25 mb based upon the assumed design speeds.

  20. Altitude, Gun Ownership, Rural Areas, and Suicide

    PubMed Central

    Kim, Namkug; Mickelson, Jennie B.; Brenner, Barry E.; Haws, Charlotte A.; Yurgelun-Todd, Deborah A.; Renshaw, Perry F.

    2015-01-01

    Objective The authors recently observed a correlation between state altitude and suicide rate in the United States, which could be explained by higher rates of gun ownership and lower population density in the intermountain West. The present study evaluated the relationship between mean county and state altitude in the United States and total age-adjusted suicide rates, firearm-related suicide rates, and non-firearm-related suicide rates. The authors hypothesized that altitude would be significantly associated with suicide rate. Method Elevation data were calculated with an approximate spatial resolution of 0.5 km, using zonal statistics on data sets compiled from the National Geospatial-Intelligence Agency and the National Aeronautics and Space Administration. Suicide and population density data were obtained through the Centers for Disease Control and Prevention (CDC) WONDER database. Gun ownership data were obtained through the CDC’s Behavioral Risk Factor Surveillance System. Results A significant positive correlation was observed between age-adjusted suicide rate and county elevation (r=0.51). Firearm (r=0.41) and non-firearm suicide rates (r=0.32) were also positively correlated with mean county elevation. Conclusions When altitude, gun ownership, and population density are considered as predictor variables for suicide rates on a state basis, altitude appears to be a significant independent risk factor. This association may be related to the effects of metabolic stress associated with mild hypoxia in individuals with mood disorders. PMID:20843869

  1. High altitude pulmonary edema in mountain climbers.

    PubMed

    Korzeniewski, Krzysztof; Nitsch-Osuch, Aneta; Guzek, Aneta; Juszczak, Dariusz

    2015-04-01

    Every year thousands of ski, trekking or climbing fans travel to the mountains where they stay at the altitude of more than 2500-3000m above sea level or climb mountain peaks, often exceeding 7000-8000m. High mountain climbers are at a serious risk from the effects of adverse environmental conditions prevailing at higher elevations. They may experience health problems resulting from hypotension, hypoxia or exposure to low temperatures; the severity of those conditions is largely dependent on elevation, time of exposure as well as the rate of ascent and descent. A disease which poses a direct threat to the lives of mountain climbers is high altitude pulmonary edema (HAPE). It is a non-cardiogenic pulmonary edema which typically occurs in rapidly climbing unacclimatized lowlanders usually within 2-4 days of ascent above 2500-3000m. It is the most common cause of death resulting from the exposure to high altitude. The risk of HAPE rises with increased altitude and faster ascent. HAPE incidence ranges from an estimated 0.01% to 15.5%. Climbers with a previous history of HAPE, who ascent rapidly above 4500m have a 60% chance of illness recurrence. The aim of this article was to present the relevant details concerning epidemiology, pathophysiology, clinical symptoms, prevention, and treatment of high altitude pulmonary edema among climbers in the mountain environment. PMID:25291181

  2. Patients with Obstructive Sleep Apnea at Altitude.

    PubMed

    Bloch, Konrad E; Latshang, Tsogyal D; Ulrich, Silvia

    2015-06-01

    Bloch, Konrad E., Tsogyal D. Latshang, and Silvia Ulrich. Patients with obstructive sleep apnea at altitude. High Alt Med Biol 16:110-116, 2015.--Obstructive sleep apnea (OSA) is highly prevalent in the general population, in particular in men and women of older age. In OSA patients sleeping near sea level, the apneas/hypopneas associated with intermittent hypoxemia are predominantly due to upper airway collapse. When OSA patients stay at altitudes above 1600 m, corresponding to that of many tourist destinations, hypobaric hypoxia promotes frequent central apneas in addition to obstructive events, resulting in combined intermittent and sustained hypoxia. This induces strong sympathetic activation with elevated heart rate, cardiac arrhythmia, and systemic hypertension. There are concerns that these changes expose susceptible OSA patients, in particular those with advanced age and co-morbidities, to an excessive risk of cardiovascular and other adverse events during a stay at altitude. Based on data from randomized trials, it seems advisable for OSA patients to use continuous positive airway pressure treatment with computer controlled mask pressure adjustment (autoCPAP) in combination with acetazolamide during an altitude sojourn. If CPAP therapy is not feasible, acetazolamide alone is better than no treatment at all, as it improves oxygenation and sleep apnea and prevents excessive blood pressure rises of OSA patients at altitude. PMID:25973669

  3. Wind study for high altitude platform design

    NASA Technical Reports Server (NTRS)

    Strganac, T. W.

    1979-01-01

    An analysis of upper air winds was performed to define the wind environment at potential operating altitudes for high altitude powered platform concepts. Wind conditions of the continental United States, Pacific area (Alaska to Sea of Japan), and European area (Norwegian and Mediterranean Sea) were obtained using a representative network of sites selected based upon adequate high altitude sampling, geographic dispersion, and observed upper wind patterns. A data base of twenty plus years of rawinsonde gathered wind information was used in the analysis. Annual variations from surface to 10 mb pressure altitude were investigated to encompass the practical operating range for the platform concepts. Parametric analysis for the United States and foreign areas was performed to provide a basis for vehicle system design tradeoffs. This analysis of wind magnitudes indicates the feasibility of annual operation at a majority of sites and more selective seasonal operation for the extreme conditions between the pressure altitudes of 100 to 25 mb based upon the assumed design speeds.

  4. Sprite initiation altitude measured by triangulation

    NASA Astrophysics Data System (ADS)

    Stenbaek-Nielsen, H. C.; Haaland, R.; McHarg, M. G.; Hensley, B. A.; Kanmae, T.

    2010-03-01

    High time resolution (10,000 frames per second) images of sprites combined with multistation concurrent video recordings have provided data for triangulation of the altitude of the initial sprite onset. The high-speed images were obtained from the Langmuir Laboratory, New Mexico, during summer campaigns in 2007 and 2008 with video observations from sites at Portales, New Mexico, and Las Vegas, New Mexico. Sprites start with one or more downward-propagating streamer heads. The triangulated onset altitudes of this initial downward streamer vary between 66 and 89 km. In some sprites the downward streamers are followed a little later by upward-propagating streamers. The upward streamers start from a lower altitude and existing luminous sprite structures and their triangulated altitudes vary from 64 to 78 km. The downward streamers create C sprite characteristics, while the upward streamers form the broad diffuse tops of carrot sprites. In the sprites analyzed the higher onset altitudes for the downward-propagating initial streamers were associated with C sprites and the lower with carrot sprites, but our larger data set indicates that this is not generally the case. It appears that the dominant sprite types vary from year to year, indicating that some longer-lasting environmental parameter, such as mesospheric conductivity and composition or thunderstorm cloud dynamics, may play an important role in determining the types of sprites observed.

  5. Responses of the autonomic nervous system in altitude adapted and high altitude pulmonary oedema subjects

    NASA Astrophysics Data System (ADS)

    Mathew, Lazar; Purkayastha, S. S.; Jayashankar, A.; Radhakrishnan, U.; Sen Gupta, J.; Nayar, H. S.

    1985-06-01

    Studies were carried out to ascertain the role of sympatho-parasympathetic responses in the process of adaptation to altitude. The assessment of status of autonomic balance was carried out in a group of 20 young male subjects by recording their resting heart rate, blood pressure, oral temperature, mean skin temperature, extremity temperatures, pupillary diameter, cold pressor response, oxygen consumption, cardioacceleration during orthostasis and urinary excretion of catecholamines; in a thermoneutral laboratory. The same parameters were repeated on day 3 and at weekly intervals for a period of 3 weeks, after exposing them to 3,500 m; and also after return to sea level. At altitude, similar studies were carried out in a group of 10 acclimatized lowlanders, 10 high altitude natives and 6 patients who had recently recovered from high altitude pulmonary oedema. In another phase, similar studies were done in two groups of subjects, one representing 15 subjects who had stayed at altitude (3,500 4,000 m) without any ill effects and the other comprising of 10 subjects who had either suffered from high altitude pulmonary oedema (HAPO) or acute mountain sickness (AMS). The results revealed sympathetic overactivity on acute induction to altitude which showed gradual recovery on prolonged stay, the high altitude natives had preponderance to parasympathetic system. Sympathetic preponderance may not be an essential etiological factor for the causation of maladaptation syndromes.

  6. Chromatin association of the SMC5/6 complex is dependent on binding of its NSE3 subunit to DNA

    PubMed Central

    Zabrady, Katerina; Adamus, Marek; Vondrova, Lucie; Liao, Chunyan; Skoupilova, Hana; Novakova, Marketa; Jurcisinova, Lenka; Alt, Aaron; Oliver, Antony W.; Lehmann, Alan R.; Palecek, Jan J.

    2016-01-01

    SMC5/6 is a highly conserved protein complex related to cohesin and condensin, which are the key components of higher-order chromatin structures. The SMC5/6 complex is essential for proliferation in yeast and is involved in replication fork stability and processing. However, the precise mechanism of action of SMC5/6 is not known. Here we present evidence that the NSE1/NSE3/NSE4 sub-complex of SMC5/6 binds to double-stranded DNA without any preference for DNA-replication/recombination intermediates. Mutations of key basic residues within the NSE1/NSE3/NSE4 DNA-binding surface reduce binding to DNA in vitro. Their introduction into the Schizosaccharomyces pombe genome results in cell death or hypersensitivity to DNA damaging agents. Chromatin immunoprecipitation analysis of the hypomorphic nse3 DNA-binding mutant shows a reduced association of fission yeast SMC5/6 with chromatin. Based on our results, we propose a model for loading of the SMC5/6 complex onto the chromatin. PMID:26446992

  7. Chromatin association of the SMC5/6 complex is dependent on binding of its NSE3 subunit to DNA.

    PubMed

    Zabrady, Katerina; Adamus, Marek; Vondrova, Lucie; Liao, Chunyan; Skoupilova, Hana; Novakova, Marketa; Jurcisinova, Lenka; Alt, Aaron; Oliver, Antony W; Lehmann, Alan R; Palecek, Jan J

    2016-02-18

    SMC5/6 is a highly conserved protein complex related to cohesin and condensin, which are the key components of higher-order chromatin structures. The SMC5/6 complex is essential for proliferation in yeast and is involved in replication fork stability and processing. However, the precise mechanism of action of SMC5/6 is not known. Here we present evidence that the NSE1/NSE3/NSE4 sub-complex of SMC5/6 binds to double-stranded DNA without any preference for DNA-replication/recombination intermediates. Mutations of key basic residues within the NSE1/NSE3/NSE4 DNA-binding surface reduce binding to DNA in vitro. Their introduction into the Schizosaccharomyces pombe genome results in cell death or hypersensitivity to DNA damaging agents. Chromatin immunoprecipitation analysis of the hypomorphic nse3 DNA-binding mutant shows a reduced association of fission yeast SMC5/6 with chromatin. Based on our results, we propose a model for loading of the SMC5/6 complex onto the chromatin. PMID:26446992

  8. Altitude Performance of J35-A-17 Turbojet Engine in an Altitude Chamber

    NASA Technical Reports Server (NTRS)

    Vincent, K. R.; Gale, B. M.

    1951-01-01

    An investigation of the altitude performance characteristics of an Allison J35-A-17 turbojet engines have been conducted in an altitude chamber at the NACA Lewis laboratory. Engine performance was obtained over a range of altitudes from 20,000 to 60,000 feet at a flight Mach number of 0.62 and a range of flight Mach numbers from 0.42 to 1.22 at an altitude of 30,000 feet. The performance of the engine over the range investigated could be generalized up to an altitude of 30,000 feet. Performance of the engine at any flight Mach number in the range investigated can be predicted for those operating condition a t which critical flow exits in the exhaust nozzle with the exception of the variables corrected net thrust, and net-thrust specific fuel consumption.

  9. Tests of artificial flight at high altitudes

    NASA Technical Reports Server (NTRS)

    Gradenwitz, Arthur

    1920-01-01

    If we wish to form an accurate idea of the extraordinary progress achieved in aeronautics, a comparison must be made of the latest altitude records and the figures regarded as highest attainable limit some ten years ago. It is desirable, for two reasons, that we should be able to define the limit of the altitudes that can be reached without artificial aid. First, to know to what extent the human body can endure the inhalation of rarified air. Second, the mental capacity of the aviator must be tested at high altitudes and the limit known below which he is able to make reliable observations without being artificially supplied with oxygen. A pneumatic chamber was used for the most accurate observations.

  10. Sonic Thermometer for High-Altitude Balloons

    NASA Technical Reports Server (NTRS)

    Bognar, John

    2012-01-01

    The sonic thermometer is a specialized application of well-known sonic anemometer technology. Adaptations have been made to the circuit, including the addition of supporting sensors, which enable its use in the high-altitude environment and in non-air gas mixtures. There is a need to measure gas temperatures inside and outside of superpressure balloons that are flown at high altitudes. These measurements will allow the performance of the balloon to be modeled more accurately, leading to better flight performance. Small thermistors (solid-state temperature sensors) have been used for this general purpose, and for temperature measurements on radiosondes. A disadvantage to thermistors and other physical (as distinct from sonic) temperature sensors is that they are subject to solar heating errors when they are exposed to the Sun, and this leads to issues with their use in a very high-altitude environment

  11. Paschen Considerations for High Altitude Airships

    NASA Technical Reports Server (NTRS)

    Ferguson, D. C.; Hillard, G. B.

    2004-01-01

    Recently, there have been several proposals submitted to funding agencies for long-lived high altitude (about 70,000 feet) airships for communications, surveillance, etc. In order for these airships to remain at altitude, high power, high efficiency, lightweight solar arrays must be used, and high efficiency power management and distribution systems must be employed. The needs for high power and high efficiency imply high voltage systems. However, the air pressure at these extreme altitudes is such that electrical power systems will be near the Paschen discharge minimum over a wide range of electrode separations. In this paper, preliminary calculations are made for acceptable high voltage design practices under ambient, hydrogen and helium gas atmospheres.

  12. Achievements and Planned Programmes of Activities of The Csg.5/6 "geodynamics of Northern Carpathians"

    NASA Astrophysics Data System (ADS)

    Zablotskyj, F.; Tretyak, K.

    Within the programme of the regional group CSG.5/6 "Geodynamics of Northern Carpathians", the following main lines are carried out. (1) Geodetic and geophysical investigations of the recent crustal movements and geophysical analysis of deep struc- ture on the Carpathian geodynamic test field. (2) Subsequent study of geological struc- tures in the region of Northern Carpathians. On the initiative of the Main Astronomical Observatory, the National Space Agency and the Aerogeodetic Enterprise of Ukraine two permanent GPS stations, UZHL and SULP, were being established during last 1.5 years. The first one is situated in the zone of Transcarpathian flexure (Uzhgorod, University) and the second one - in the west of East-European plate (the Precarpathi- ans, Lviv, Polytechnic University). In addition to the long-term project "Restoration of Ukrainian-Polish complex geophysical station at Pip Ivan Mount in Charnohora (Ukrainian Carpathians)", the following actions are planned for 2002-2004. (1) To carry out the complex geodetic, geophysical, geological and geomorphological in- vestigations in this region, which is less studied in comparison with other areas in Carpathians. The comparison of simultaneous appearance of geophysical processes in these regions will allow detect a degree of influence of endogenic, exogenic, and antro- pogenig factors on present day hydro-geological processes in the whole Carpathian region. (2) To create a network of permanent stations for the complex geophysical and geodynamic monitoring, which will include measurements of intensity of Earth's surface deformation field, remote photogrammetric measurements of intensity of de- structive and shift processes, the determination of parameters of gravity and mag- netic fields, seismic and electrometric measurements, spectral analysis of space im- ages for quality and quantity estimations of technogenic and antropogenic activity, generalization of data on evolution and dynamics of river systems and

  13. The 2012 MW5.6 earthquake in the vicinity of the city of Sofia

    NASA Astrophysics Data System (ADS)

    Simeonova, Stela; Solakov, Dimcho; Aleksandrova, Irena; Dimitrova, Liliya; Popova, Iliana; Raykova, Plamena

    2013-04-01

    The territory of Bulgaria represents a typical example of high seismic risk area in the eastern part of the Balkan Peninsula. The neotectonic movements on the Balkan Peninsula were controlled by extensional collapse of the Late Alpin orogen, and were influenced by extension behind the Aegean arc and by the complicated vertical and horizontal movements in the Pannonian region. The city of Sofia is the capital of Bulgaria. It is situated in the centre of the Sofia seismic zone that is the most populated (more than 1.2 mil. inhabitants), industrial and cultural region of Bulgaria that faces considerable earthquake risk. Seismicity in the zone is related mainly to the marginal neotectonic faults of Sofia graben. The available historical documents prove the occurrence of destructive earthquakes during the 15th-18th centuries in the Sofia zone. In 19th century the city of Sofia has experienced two strong earthquakes: the 1818 earthquake with epicentral intensity I0=8-9 MSK and the 1858 earthquake with I0=IX-X MSK64. The 1858 earthquake caused heavy destruction in the town of Sofia and the appearance of thermal springs in the western part of the town. After a quiescence of about 50 years a strong event with M=6.5 occurred in 1905 near the western marginal part of the Sofia zone. During the 20th century the strongest event occurred in the vicinity of the city of Sofia is the 1917 earthquake with MS=5.3 (I0=7-8 MSK64). The earthquake caused a lot of damages in the town and changed the capacity of the thermal mineral springs in Sofia and the surrounding villages. The earthquake was felt in an area of 50000 km2 and followed by aftershocks, which lasted more than one year. Almost a century later (95 years) an earthquake of moment magnitude 5.6 hit Sofia seismic zone, on May 22nd, 2012, at 25 km south west of the city of Sofia. This shallow earthquake was largely felt in the region and up to Greece, FYROM, Serbia and Romania. No severe injuries have been reported so far, though

  14. Structural reassignment, absolute configuration, and conformation of hypurticin, a highly flexible polyacyloxy-6-heptenyl-5,6-dihydro-2H-pyran-2-one.

    PubMed

    Mendoza-Espinoza, José Alberto; López-Vallejo, Fabian; Fragoso-Serrano, Mabel; Pereda-Miranda, Rogelio; Cerda-García-Rojas, Carlos M

    2009-04-01

    The structural reassignment, absolute configuration, and conformational behavior of the highly flexible natural product hypurticin (pectinolide E), 6S-[3'S,5'R,6'S-triacetoxy-1Z-heptenyl]-5S-acetoxy-5,6-dihydro-2H-pyran-2-one (1), were ascertained by a molecular modeling protocol, which includes extensive conformational searching, geometry optimization by DFT B3LYP/DGDZVP calculations, and comparison between the theoretical (DFT) and experimental (1)H-(1)H NMR coupling constants. Hyptolide (2), a related cytotoxic 5,6-dihydro-2H-pyran-2-one that increased the S phase of the HeLa cell cycle, was employed as a reference substance to validate the theoretical protocol designed to characterize the 3D properties of compound 1. The related synthetic derivative, tri-O-acetyl-3,6-dideoxy-d-glucose diphenyldithioacetal (14), was prepared by a six-step reaction sequence starting from d-glucose and served as an enantiopure building block to reinforce the structural and configurational assignment of 1. This protocol proved to be an important tool for the structural characterization of highly flexible bioactive polyoxygenated natural products. PMID:19265396

  15. Synthesis of 5,6-dihydro-4H-benzo[d]isoxazol-7-one and 5,6-dihydro-4H-isoxazolo[5,4-c]pyridin-7-one derivatives as potential Hsp90 inhibitors.

    PubMed

    Musso, Loana; Cincinelli, Raffaella; Giannini, Giuseppe; Manetti, Fabrizio; Dallavalle, Sabrina

    2015-11-01

    A novel class of 5,6-dihydro-4H-benzo[d]isoxazol-7-ones and 5,6-dihydro-4H-isoxazolo[5,4-c]pyridin-7-ones was designed, synthesized, and assayed to investigate the affinity toward Hsp90 protein. The synthetic route was based on a 1,3-dipolar cycloaddition of nitriloxides, generated in situ from suitable benzaldoximes, with 2-bromocyclohex-2-enones or 3-bromo-5,6-dihydro-1H-pyridin-2-ones. Whereas all the compounds bearing a benzamide group on the bicyclic scaffold were devoid of activity, the derivatives carrying a resorcinol-like fragment showed a remarkable inhibitory effect on Hsp90. Docking calculations were performed to investigate the orientation of the new compounds within the binding site of the enzyme. PMID:25855505

  16. Control of breathing and the circulation in high-altitude mammals and birds.

    PubMed

    Ivy, Catherine M; Scott, Graham R

    2015-08-01

    Hypoxia is an unremitting stressor at high altitudes that places a premium on oxygen transport by the respiratory and cardiovascular systems. Phenotypic plasticity and genotypic adaptation at various steps in the O2 cascade could help offset the effects of hypoxia on cellular O2 supply in high-altitude natives. In this review, we will discuss the unique mechanisms by which ventilation, cardiac output, and blood flow are controlled in high-altitude mammals and birds. Acclimatization to high altitudes leads to some changes in respiratory and cardiovascular control that increase O2 transport in hypoxia (e.g., ventilatory acclimatization to hypoxia). However, acclimatization or development in hypoxia can also modify cardiorespiratory control in ways that are maladaptive for O2 transport. Hypoxia responses that arose as short-term solutions to O2 deprivation (e.g., peripheral vasoconstriction) or regional variation in O2 levels in the lungs (i.e., hypoxic pulmonary vasoconstriction) are detrimental at in chronic high-altitude hypoxia. Evolved changes in cardiorespiratory control have arisen in many high-altitude taxa, including increases in effective ventilation, attenuation of hypoxic pulmonary vasoconstriction, and changes in catecholamine sensitivity of the heart and systemic vasculature. Parallel evolution of some of these changes in independent highland lineages supports their adaptive significance. Much less is known about the genomic bases and potential interactive effects of adaptation, acclimatization, developmental plasticity, and trans-generational epigenetic transfer on cardiorespiratory control. Future work to understand these various influences on breathing and circulation in high-altitude natives will help elucidate how complex physiological systems can be pushed to their limits to maintain cellular function in hypoxia. PMID:25446936

  17. Passive range estimation for rotorcraft low-altitude flight

    NASA Technical Reports Server (NTRS)

    Sridhar, B.; Suorsa, R.; Hussien, B.

    1991-01-01

    The automation of rotorcraft low-altitude flight presents challenging problems in control, computer vision and image understanding. A critical element in this problem is the ability to detect and locate obstacles, using on-board sensors, and modify the nominal trajectory. This requirement is also necessary for the safe landing of an autonomous lander on Mars. This paper examines some of the issues in the location of objects using a sequence of images from a passive sensor, and describes a Kalman filter approach to estimate the range to obstacles. The Kalman filter is also used to track features in the images leading to a significant reduction of search effort in the feature extraction step of the algorithm. The method can compute range for both straight line and curvilinear motion of the sensor. A laboratory experiment was designed to acquire a sequence of images along with sensor motion parameters under conditions similar to helicopter flight. Range estimation results using this imagery are presented.

  18. Passive range estimation for rotorcraft low-altitude flight

    NASA Technical Reports Server (NTRS)

    Sridhar, B.; Suorsa, R.; Hussien, B.

    1993-01-01

    The automation of rotorcraft low-altitude flight presents challenging problems in control, computer vision and image understanding. A critical element in this problem is the ability to detect and locate obstacles, using on-board sensors, and modify the nominal trajectory. This requirement is also necessary for the safe landing of an autonomous lander on Mars. This paper examines some of the issues in the location of objects using a sequence of images from a passive sensor, and describes a Kalman filter approach to estimate the range to obstacles. The Kalman filter is also used to track features in the images leading to a significant reduction of search effort in the feature extraction step of the algorithm. The method can compute range for both straight line and curvilinear motion of the sensor. A laboratory experiment was designed to acquire a sequence of images along with sensor motion parameters under conditions similar to helicopter flight. Range estimation results using this imagery are presented.

  19. Habit modification of 5,6-dimethyl-1H-benzotriazole in the presence of nonionic triblock copolymers

    NASA Astrophysics Data System (ADS)

    Molloy, Meghan R.; Partch, Richard

    2013-06-01

    The effects of different nonionic surfactants on the habit modification of 5,6-dimethyl-1H-benzotriazole (5,6-DMBTA) were evaluated. Three different triblock copolymers, Pluronic® F-127, Pluronic® L44NF, and Pluronic® P-123 were selected as nonionic surfactants. Crystallization was achieved by pH adjustment in an aqueous solution with or without the presence of surfactants. Pluronic® P-123 was found to have the most dramatic effect in changing the crystal habit of 5,6-DMBTA from needles to platelets. The surfactant with a smaller hydrophobic block, Pluronic® L44NF, or the one with a larger hydrophilic block, Pluronic® F-127, yield only shorter needles for the crystal habit. This indicates that both blocks of a surfactant backbone have an impact on habit modification. Analytical data confirmed that none of the three surfactants were incorporated into the crystal lattice of 5,6-DMBTA after crystallization. All the habit modified crystals have the same crystal form as the original 5,6-DMBTA crystal sample, indicating that solely a habit modifying process took place.

  20. Microbial Dechlorination of 2,3,5,6-Tetrachlorobiphenyl under Anaerobic Conditions in the Absence of Soil or Sediment

    PubMed Central

    Cutter, Leah; Sowers, Kevin R.; May, Harold D.

    1998-01-01

    Bacterial enrichment cultures developed with Baltimore Harbor (BH) sediments were found to reductively dechlorinate 2,3,5,6-tetrachlorobiphenyl (2,3,5,6-CB) when incubated in a minimal estuarine medium containing short-chain fatty acids under anaerobic conditions with and without the addition of sediment. Primary enrichment cultures formed both meta and ortho dechlorination products from 2,3,5,6-CB. The lag time preceding dechlorination decreased from 30 to less than 20 days as the cultures were sequentially transferred into estuarine medium containing dried, sterile BH sediment. In addition, only ortho dechlorination was observed following transfer of the cultures. Sequential transfer into medium without added sediment also resulted in the development of a strict ortho-dechlorinating culture following a lag of more than 100 days. Upon further transfer into the minimal medium without sediment, the lag time decreased to less than 50 days. At this stage all cultures, regardless of the presence of sediment, would produce 2,3,5-CB and 3,5-CB from 2,3,5,6-CB. The strict ortho-dechlorinating activity in the sediment-free cultures has remained stable for more than 1 year through several transfers. These results reveal that the classical microbial enrichment technique using a minimal medium with a single polychlorinated biphenyl (PCB) congener selected for ortho dechlorination of 2,3,5,6-CB. Furthermore, this is the first report of sustained anaerobic PCB dechlorination in the complete absence of soil or sediment. PMID:9687458

  1. Repeated cocaine weakens GABAB-Girk signaling in Layer 5/6 pyramidal neurons in the prelimbic cortex

    PubMed Central

    Hearing, Matthew; Kotecki, Lydia; de Velasco, Ezequiel Marron Fernandez; Fajardo-Serrano, Ana; Luján, Rafael; Wickman, Kevin

    2013-01-01

    Summary Repeated cocaine exposure triggers adaptations in Layer 5/6 glutamatergic neurons in the medial prefrontal cortex (mPFC) that promote behavioral sensitization and drug-seeking behavior. While suppression of metabotropic inhibitory signaling has been implicated in these behaviors, underlying mechanisms are unknown. Here, we show that Girk/KIR3 channels mediate most of the GABAB receptor (GABABR)-dependent inhibition of Layer 5/6 pyramidal neurons in the mPFC and that repeated cocaine suppresses this pathway. This adaptation was selective for GABABR-dependent Girk signaling in Layer 5/6 pyramidal neurons of the prelimbic cortex (PrLC) and involved a D1/5 dopamine receptor- and phosphorylation-dependent internalization of GABABR and Girk channels. Persistent suppression of Girk signaling in Layer 5/6 of the dorsal mPFC enhanced cocaine-induced locomotor activity and occluded behavioral sensitization. Thus, the cocaine-induced suppression of GABABR-Girk signaling in Layer 5/6 pyramidal neurons of the prelimbic cortex appears to represent an early adaptation critical for promoting addiction-related behavior. PMID:24094109

  2. The Power of Aircraft Engines at Altitude

    NASA Technical Reports Server (NTRS)

    Ragazzi, Paolo

    1939-01-01

    The subject of the present paper is confined to the investigations and methods employed by the Fiat company in their studies on the altitude performance of an air-cooled engine of the production type. The experimental set-up as well as test engine data are provided.

  3. Sickle Cell Trait, Exercise, and Altitude.

    ERIC Educational Resources Information Center

    Eichner, Edward R.

    1986-01-01

    Sickle cell trait is generally benign and does not shorten life, but it may confer some small risk with extremes of exercise or altitude. Research concerning these risks is presented, and it is concluded sickle cell trait is no barrier to outstanding athletic performance. (Author/MT)

  4. AWT aerodynamic design status. [Altitude Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Davis, Milt W.

    1984-01-01

    The aerodynamic design of the NASA Altitude Wind Tunnel is presented in viewgraph format. The main topics covered are: analysis of a plenum evacuation system; airline definition and pressure loss code development; contraction geometry and code analysis; and design of the two stage fan. Flow characteristics such as pressure ratio, mach number distribution, adiabatic efficiency, and losses are shown.

  5. Sextant measures spacecraft altitude without gravitational reference

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Horizon-sensing sextant measures the altitude of an orbiting spacecraft without gravitational reference by optically measuring the dip angle to the horizon along a line of sight in each of two planes. The sextant scans over a relatively limited field of view.

  6. SRB Altitude Switch Assembly Wire Harness Failure

    NASA Astrophysics Data System (ADS)

    Blanche, Jim

    2002-01-01

    This paper presents an assessment of two wire harness failures that had occurred in Solid Rocket Booster Altitude Switch Assemblies S/N 200001 and S/N 20002. A list of modifications to EDU #4 and modification of qualification units 2000001 and 2000002 are also presented.

  7. Dietary Recommendations for Cyclists during Altitude Training

    PubMed Central

    Michalczyk, Małgorzata; Czuba, Miłosz; Zydek, Grzegorz; Zając, Adam; Langfort, Józef

    2016-01-01

    The concept of altitude or hypoxic training is a common practice in cycling. However, several strategies for training regimens have been proposed, like “live high, train high” (LH-TH), “live high, train low” (LH-TL) or “intermittent hypoxic training” (IHT). Each of them combines the effect of acclimatization and different training protocols that require specific nutrition. An appropriate nutrition strategy and adequate hydration can help athletes achieve their fitness and performance goals in this unfriendly environment. In this review, the physiological stress of altitude exposure and training will be discussed, with specific nutrition recommendations for athletes training under such conditions. However, there is little research about the nutrition demands of athletes who train at moderate altitude. Our review considers energetic demands and body mass or body composition changes due to altitude training, including respiratory and urinary water loss under these conditions. Carbohydrate intake recommendations and hydration status are discussed in detail, while iron storage and metabolism is also considered. Last, but not least the risk of increased oxidative stress under hypoxic conditions and antioxidant supplementation suggestions are presented. PMID:27322318

  8. High power synchronous altitude satellite system

    SciTech Connect

    Keigler, J.E.

    1981-12-01

    The design and attitude control system of the illustrated momentum stabilized synchronous altitude spacecraft are such that relatively large amounts of electrical power may be derived from its sun oriented planar solar array. The system is illustrated and the control of the spacecraft to stabilize it about all three axes with respect to the sun is described.

  9. High-altitude physiology: lessons from Tibet

    NASA Astrophysics Data System (ADS)

    Wagner, Peter D.; Simonson, Tatum S.; Wei, Guan; Wagner, Harrieth; Wuren, Tanna; Yan, Ma; Qin, Ga; Ge, Rili

    2013-05-01

    Polycythemia is a universal lowlander response to altitude; healthy Andean high-altitude natives also have elevated [Hb]. While this may enhance O2 transport to tissues, studies have shown that acute isovolumic changes in [Hb] do not affect exercise capacity. Many high-altitude Tibetans have evolved sea-level values of [Hb], providing a natural opportunity to study this issue. In 21 young healthy male Tibetans with [Hb] between 15 and 23 g/dl, we measured VO2MAX and O2 transport capacity at 4200m. VO2MAX was higher when [Hb] was lower (P<0.05), enabled by both higher cardiac output and muscle O2 diffusional conductance, but neither ventilation nor the alveolar-arterial PO2 difference (AaPO2) varied with [Hb]. In contrast, Andean high altitude natives remain polycythemic with larger lungs and higher lung diffusing capacity, a smaller exercising AaPO2, and lower ventilation. The challenges now are (1) to understand the different adaptive pathways used by Andeans and Tibetans, and (2) to determine in Tibetans whether, during evolution, reduced [Hb] appeared first, causing compensatory cardiac and muscle adaptations, or if enhanced cardiac function and muscle O2 transport capacity appeared first, permitting secondary reduction in [Hb]. For (2), further research is necessary to determine the basis of enhanced cardiac function and muscle O2 transport, and identify molecular targets of evolution in heart and muscle. Putative mutations can then be timed and compared to appearance of those affecting [Hb].

  10. The visually guided control of simulated altitude

    NASA Technical Reports Server (NTRS)

    Johnson, W. W.; Tsang, P. S.; Bennett, C. T.; Phatak, A. V.

    1989-01-01

    Simulated "flights" over three different ground textures were used to examine people's ability to extract optical information useful for active regulation of altitude. The textures were regularly spaced lines as follows: 1) orthogonal to the direction of flight (latitude texture); 2) parallel to the direction of flight (meridian texture); and 3) both parallel and orthogonal (square texture). Visual constant velocity forward flight simulations were displayed on a CRT screen, and subjects asked to maintain one of three initial altitudes using a rate control stick. This task was made difficult by the presence of lateral (irrelevant) and vertical (relevant) "wind gusts." The attitude never varied as winds, forward speed, and vertical rate control resulted in only translational movements. Adjusted root mean square errors (ARMSE) showed altitude regulation was more difficult at higher altitudes and when flying over meridian textures. Refined analysis of a single subject's data showed that this was due both to poorer regulation of the vertical wind disturbance and to a tendency to confuse the lateral wind disturbance for a vertical disturbance.

  11. Safely Enabling Low-Altitude Airspace Operations

    NASA Technical Reports Server (NTRS)

    Kopardekar, Parimal

    2015-01-01

    Near-term Goal: Enable initial low-altitude airspace and UAS operations with demonstrated safety as early as possible, within 5 years. Long-term Goal: Accommodate increased UAS operations with highest safety, efficiency, and capacity as much autonomously as possible (10-15 years).

  12. Safely Enabling Low-Altitude Airspace Operations

    NASA Technical Reports Server (NTRS)

    Kopardekar, Parimal

    2015-01-01

    Near-term Goal - Enable initial low-altitude airspace and UAS operations with demonstrated safety as early as possible, within 5 years. Long-term Goal - Accommodate increased UAS operations with highest safety, efficiency, and capacity as much autonomously as possible (10-15 years).

  13. High-altitude solar power platform

    SciTech Connect

    Bailey, M.D.; Bower, M.V.

    1992-04-01

    Solar power is a preeminent alternative to conventional aircraft propulsion. With the continued advances in solar cells, fuel cells, and composite materials technology, the solar powered airplane is no longer a simple curiosity constrained to flights of several feet in altitude or minutes of duration. A high altitude solar powered platform (HASPP) has several potential missions, including communications and agriculture. In remote areas, a HASPP could be used as a communication link. In large farming areas, a HASPP could perform remote sensing of crops. The impact of HASPP in continuous flight for one year on agricultural monitoring mission is presented. This mission provides farmers with near real-time data twice daily from an altitude which allows excellant resolution on water conditions, crop diseases, and insect infestation. Accurate, timely data will enable farmers to increase their yield and efficiency. A design for HASPP for the foregoing mission is presented. In the design power derived from solar cells covering the wings is used for propulsion, avionics, and sensors. Excess power produced midday will be stored in fuel cells for use at night to maintain altitude and course.

  14. Altitude Adaptation: A Glimpse Through Various Lenses

    PubMed Central

    2015-01-01

    Abstract Simonson, Tatum S. Altitude adaptation: A glimpse through various lenses. High Alt Med Biol 16:125–137, 2015.—Recent availability of genome-wide data from highland populations has enabled the identification of adaptive genomic signals. Some of the genomic signals reported thus far among Tibetan, Andean, and Ethiopian are the same, while others appear unique to each population. These genomic findings parallel observations conveyed by decades of physiological research: different continental populations, resident at high altitude for hundreds of generations, exhibit a distinct composite of traits at altitude. The most commonly reported signatures of selection emanate from genomic segments containing hypoxia-inducible factor (HIF) pathway genes. Corroborative evidence for adaptive significance stems from associations between putatively adaptive gene copies and sea-level ranges of hemoglobin concentration in Tibetan and Amhara Ethiopians, birth weights and metabolic factors in Andeans and Tibetans, maternal uterine artery diameter in Andeans, and protection from chronic mountain sickness in Andean males at altitude. While limited reports provide mechanistic insights thus far, efforts to identify and link precise genetic variants to molecular, physiological, and developmental functions are underway, and progress on the genomics front continues to provide unprecedented movement towards these goals. This combination of multiple perspectives is necessary to maximize our understanding of orchestrated biological and evolutionary processes in native highland populations, which will advance our understanding of both adaptive and non-adaptive responses to hypoxia. PMID:26070057

  15. 78 FR 9583 - IFR Altitudes; Miscellaneous Amendments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-11

    ... ``significant rule'' under DOT Regulatory Policiesand Procedures (44 FR 11034; February 26, 1979); and (3) does... Changeover Points FROM TO MEA MAA Sec. 95.3000 Low Altitude RNAV Routes Sec. 95.3254 RNAV Route T254 is Amended to Read in Part COLLEGE STATION, TX VORTAC HIPPS, TX FIX 3000 15000 HIPPS, TX FIX EAKES, TX...

  16. Measurement of aircraft speed and altitude

    NASA Technical Reports Server (NTRS)

    Gracey, W.

    1980-01-01

    Problems involved in measuring speed and altitude with pressure-actuated instruments (altimeter, airspeed indicator, true-airspeed indicator, Machmeter, and vertical-speed indicator) are examined. Equations relating total pressure and static pressure to the five flight quantities are presented, and criteria for the design of total and static pressure tubes are given. Calibrations of typical static pressure installations (fuselage nose, wing tip, vertical fin, and fuselage vent) are presented, various methods for flight calibration of these installations are described, and the calibration of a particular installation by two of the methods is described in detail. Equations are given for estimating the effects of pressure lag and leaks. Test procedures for the laboratory calibration of the five instruments are described, and accuracies of mechanical and electrical instruments are presented. Operational use of the altimeter for terrain clearance and vertical separation of aircraft is discussed, along with flight technical errors and overall altitude errors of aircraft in cruise operations. Altitude-measuring techniques based on a variety of properties of the Earth and the atmosphere are included. Two appendixes present airspeed and altitude tables and sample calculations for determining the various flight parameters from measured total and static pressures.

  17. The morbid anatomy of high altitude

    PubMed Central

    Heath, Donald

    1979-01-01

    The morbid anatomical changes which take place in man and animals exposed to the chronic hypoxia of residence at high altitude are briefly reviewed. ImagesFig. 1Fig. 2Fig. 3Fig. 5Fig. 4Fig. 6Fig. 7Fig. 8 PMID:493205

  18. Dietary Recommendations for Cyclists during Altitude Training.

    PubMed

    Michalczyk, Małgorzata; Czuba, Miłosz; Zydek, Grzegorz; Zając, Adam; Langfort, Józef

    2016-01-01

    The concept of altitude or hypoxic training is a common practice in cycling. However, several strategies for training regimens have been proposed, like "live high, train high" (LH-TH), "live high, train low" (LH-TL) or "intermittent hypoxic training" (IHT). Each of them combines the effect of acclimatization and different training protocols that require specific nutrition. An appropriate nutrition strategy and adequate hydration can help athletes achieve their fitness and performance goals in this unfriendly environment. In this review, the physiological stress of altitude exposure and training will be discussed, with specific nutrition recommendations for athletes training under such conditions. However, there is little research about the nutrition demands of athletes who train at moderate altitude. Our review considers energetic demands and body mass or body composition changes due to altitude training, including respiratory and urinary water loss under these conditions. Carbohydrate intake recommendations and hydration status are discussed in detail, while iron storage and metabolism is also considered. Last, but not least the risk of increased oxidative stress under hypoxic conditions and antioxidant supplementation suggestions are presented. PMID:27322318

  19. SHARP (Stationary High Altitude Relay Platform) - Rectenna and low altitude tests

    NASA Astrophysics Data System (ADS)

    Schlesak, J. J.; Alden, A.; Ohno, T.

    This paper describes a planned low-altitude microwave-powered flight test to demonstrate several key features of the SHARP (Stationary High Altitude Relay Platform) concept. A small-scale airplane will be flown at an altitude of about 50 m, powered by microwave energy transmitted from the ground. RF power at a frequency of 2.45 GHz will be converted to dc by an array of rectennas mounted on the lower surfaces of the airplane's wings. A novel dual-polarized rectenna system has been developed for powering the scaled model. The RF to dc power conversion efficiency of this rectenna is about 60 percent.

  20. Italian high altitude laboratories: past and present.

    PubMed

    Cogo, A; Ponchia, A; Pecchio, O; Losano, G; Cerretelli, P

    2000-01-01

    Italy is a mountainous country with a total of 88 huts and bivouacs at altitudes higher than 3,000 m. Starting in the 19th century a great deal of research in high altitude pathophysiology has been carried out in Italy and many Italian physicians have been involved in mountain medicine. Most of the Italian research has been carried out at two locations: the scientific laboratories "Angelo Mosso" on Monte Rosa (Capanna Regina Margherita and Laboratorio Angelo Mosso), and the "Pyramid" in Nepal. The Capanna Regina Margherita, located on the top of Punta Gnifetti (Monte Rosa, 4,559 m), was inaugurated in 1893. With the support of Queen Margherita of Savoy, an Observatory for scientific studies was built beside this hut in 1894. In 1980 the hut was completely rebuilt by the Italian Alpine Club. The Istituto Angelo Mosso at Col d'Olen, at the base of Monte Rosa (at 2,900 m) was inaugurated in 1907. The high altitude laboratory named the "Pyramid" was built in 1990. Made of glass and aluminium, this pyramid-shaped structure is situated in Nepal at 5,050 m. The scientific laboratories "Angelo Mosso" on Monte Rosa (mainly the Capanna Regina Margherita) and the Pyramid form a nucleus for high altitude research: the former is especially devoted to research regarding acute mountain sickness and the response to subacute hypoxia, whereas the latter is a unique facility for research responses to chronic hypoxia, the effect of exposure to very high altitude, and the study of the resident population living in the Himalayas for at least 25,000 years. PMID:11256565

  1. Estimation of high altitude Martian dust parameters

    NASA Astrophysics Data System (ADS)

    Pabari, Jayesh; Bhalodi, Pinali

    2016-07-01

    Dust devils are known to occur near the Martian surface mostly during the mid of Southern hemisphere summer and they play vital role in deciding background dust opacity in the atmosphere. The second source of high altitude Martian dust could be due to the secondary ejecta caused by impacts on Martian Moons, Phobos and Deimos. Also, the surfaces of the Moons are charged positively due to ultraviolet rays from the Sun and negatively due to space plasma currents. Such surface charging may cause fine grains to be levitated, which can easily escape the Moons. It is expected that the escaping dust form dust rings within the orbits of the Moons and therefore also around the Mars. One more possible source of high altitude Martian dust is interplanetary in nature. Due to continuous supply of the dust from various sources and also due to a kind of feedback mechanism existing between the ring or tori and the sources, the dust rings or tori can sustain over a period of time. Recently, very high altitude dust at about 1000 km has been found by MAVEN mission and it is expected that the dust may be concentrated at about 150 to 500 km. However, it is mystery how dust has reached to such high altitudes. Estimation of dust parameters before-hand is necessary to design an instrument for the detection of high altitude Martian dust from a future orbiter. In this work, we have studied the dust supply rate responsible primarily for the formation of dust ring or tori, the life time of dust particles around the Mars, the dust number density as well as the effect of solar radiation pressure and Martian oblateness on dust dynamics. The results presented in this paper may be useful to space scientists for understanding the scenario and designing an orbiter based instrument to measure the dust surrounding the Mars for solving the mystery. The further work is underway.

  2. The metabolism of gamma-2,3,4,5,6-pentachlorocyclohex-1-ene and gamma-hexachlorocyclohexane in rats.

    PubMed

    Grover, P L; Sims, P

    1965-08-01

    1. After intraperitoneal administration, gamma-hexachlorocyclohexane (Gammexane) and gamma-2,3,4,5,6-pentachlorocyclohex-1-ene were converted by rats into 2,3,5- and 2,4,5-trichlorophenol, which were excreted as free phenols and as sulphuric acid and glucuronic acid conjugates. 2. Derivatives of 2,4,5-trichlorophenol and 2,4,5-trichlorophenyl glucosiduronic acid and 2,4-dichlorophenylmercapturic acid were isolated from the urine as metabolites of gamma-2,3,4,5,6-pentachlorocyclohex-1-ene. 3. The phenolic metabolites of gamma-hexachlorocyclohexane and gamma-2,3,4,5,6-pentachlorocyclohex-1-ene isolated from urine were similar to those of 1,2,4-trichlorobenzene, which indicates that the two latter compounds are intermediates in gamma-hexachlorocyclohexane metabolism in rats. PMID:4158352

  3. Is High Altitude Pulmonary Edema Relevant to Hawai‘i?

    PubMed Central

    2014-01-01

    High altitude clinical syndromes have been described in the medical literature but may be under recognized in the state of Hawai‘i. As tourism increases, high altitude injuries may follow given the easy access to high altitude attractions. Visitors and clinicians should be aware of the dangers associated with the rapid ascent to high altitudes in the perceived comfort of a vehicle. This paper will review the basic pathophysiology, prevention, and treatment of the most serious of the high altitude clinical syndromes, high altitude pulmonary edema. PMID:25478294

  4. Kinetically Blocked Stable 5,6:12,13-Dibenzozethrene: A Laterally π-Extended Zethrene with Enhanced Diradical Character.

    PubMed

    Yadav, Priya; Das, Soumyajit; Phan, Hoa; Herng, Tun Seng; Ding, Jun; Wu, Jishan

    2016-06-17

    Although the ground-state and physical properties of zethrene and recently invented 1,2:8,9-dibenzozethrene have been well studied, the other dibenzozethrene isomer, i.e., 5,6:12,13-dibenzozethrene, remained unexplored. A short synthetic route to a kinetically blocked stable 5,6:12,13-dibenzozethrene derivative 5 is presented. The ground state is found to be open-shell singlet experimentally, and the theoretical y0 was enhanced to 0.414, which corroborates nicely with the experimental and theoretical singlet-triplet energy gap. PMID:27227758

  5. Gravity waves generated by a tropical cyclone during the STEP tropical field program - A case study

    NASA Technical Reports Server (NTRS)

    Pfister, L.; Chan, K. R.; Bui, T. P.; Bowen, S.; Legg, M.; Gary, B.; Kelly, K.; Proffitt, M.; Starr, W.

    1993-01-01

    Overflights of a tropical cyclone during the Australian winter monsoon field experiment of the Stratosphere-Troposphere Exchange Project (STEP) show the presence of two mesoscale phenomena: a vertically propagating gravity wave with a horizontal wavelength of about 110 km and a feature with a horizontal scale comparable to that of the cyclone's entire cloud shield. The larger feature is fairly steady, though its physical interpretation is ambiguous. The 110-km gravity wave is transient, having maximum amplitude early in the flight and decreasing in amplitude thereafter. Its scale is comparable to that of 100-to 150-km-diameter cells of low satellite brightness temperatures within the overall cyclone cloud shield; these cells have lifetimes of 4.5 to 6 hrs. These cells correspond to regions of enhanced convection, higher cloud altitude, and upwardly displaced potential temperature surfaces. The temporal and spatial distribution of meteorological variables associated with the 110-km gravity wave can be simulated by a slowly moving transient forcing at the anvil top having an amplitude of 400-600 m, a lifetime of 4.5-6 hrs, and a size comparable to the cells of low brightness temperature.

  6. Why Are High-Altitude Natives So Strong at Altitude? Maximal Oxygen Transport to the Muscle Cell in Altitude Natives.

    PubMed

    Lundby, Carsten; Calbet, Jose A L

    2016-01-01

    In hypoxia aerobic exercise performance of high-altitude natives is suggested to be superior to that of lowlanders; i.e., for a given altitude natives are reported to have higher maximal oxygen uptake (VO2max). The likely basis for this is a higher pulmonary diffusion capacity, which in turn ensures higher arterial O2 saturation (SaO2) and therefore also potentially a higher delivery of O2 to the exercising muscles. This review focuses on O2 transport in high-altitude Aymara. We have quantified femoral artery O2 delivery, arterial O2 extraction and calculated leg VO2 in Aymara, and compared their values with that of acclimatizing Danish lowlanders. All subjects were studied at 4100 m. At maximal exercise SaO2 dropped tremendously in the lowlanders, but did not change in the Aymara. Therefore arterial O2 content was also higher in the Aymara. At maximal exercise however, fractional O2 extraction was lower in the Aymara, and the a-vO2 difference was similar in both populations. The lower extraction levels in the Aymara were associated with lower muscle O2 conductance (a measure of muscle diffusion capacity). At any given submaximal exercise intensity, leg VO2 was always of similar magnitude in both groups, but at maximal exercise the lowlanders had higher leg blood flow, and hence also higher maximum leg VO2. With the induction of acute normoxia fractional arterial O2 extraction fell in the highlanders, but remained unchanged in the lowlanders. Hence high-altitude natives seem to be more diffusion limited at the muscle level as compared to lowlanders. In conclusion Aymara preserve very high SaO2 during hypoxic exercise (likely due to a higher lung diffusion capacity), but the effect on VO2max is reduced by a lower ability to extract O2 at the muscle level. PMID:27343089

  7. Architecture of the Smc5/6 Complex of Saccharomyces cerevisiae Reveals a Unique Interaction between the Nse5-6 Subcomplex and the Hinge Regions of Smc5 and Smc6.

    PubMed

    Duan, Xinyuan; Yang, Yan; Chen, Yu-Hung; Arenz, Jacqueline; Rangi, Gurdish K; Zhao, Xiaolan; Ye, Hong

    2009-03-27

    The evolutionarily conserved structural maintenance of chromosome (SMC) proteins forms the core structures of three multisubunit complexes as follows: cohesin, condensin, and the Smc5/6 complex. These complexes play crucial roles in different aspects of chromosomal organization, duplication, and segregation. Although the architectures of cohesin and condensin are better understood, that of the more recently identified Smc5/6 complex remains to be elucidated. We have previously shown that the Smc5/6 complex of Saccharomyces cerevisiae contains Smc5, Smc6, and six non-SMC elements (Nse1-6). In this study, we investigated the architecture of the budding yeast Smc5/6 complex employing the yeast two-hybrid assay as well as in vitro biochemical approaches using purified recombinant proteins. These analyses revealed that Smc5 and Smc6 associate with each other at their hinge regions and constitute the backbone of the complex, whereas the Nse1-6 subunits form three distinct subcomplexes/entities that interact with different regions of Smc5 and Smc6. The Nse1, -3, and -4 subunits form a stable subcomplex that binds to the head and the adjacent coiled-coil region of Smc5. Nse2 binds to the middle of the coiled-coil region of Smc5. Nse5 and Nse6 interact with each other and, as a heterodimer, bind to the hinge regions of Smc5 and Smc6. These findings provide new insights into the structures of the Smc5/6 complex and lay the foundation for further investigations into the mechanism of its functions. PMID:19141609

  8. Periodic breathing and oxygen supplementation in Chilean miners at high altitude (4200m).

    PubMed

    Moraga, Fernando A; Jiménez, Daniel; Richalet, Jean Paul; Vargas, Manuel; Osorio, Jorge

    2014-11-01

    Our objective was to determine the nocturnal ventilatory pattern and characterize the effect of oxygen enrichment on nocturnal ventilatory pattern and sleep quality in miners exposed to intermittent hypobaric hypoxia at 4200m. A total of 16 acclimatized miners were studied. Nocturnal ventilatory pattern (plethysmographic inductance), arterial oxygen saturation and heart rate (pulse oximetry) were performed in 9/16 subjects. Sleep quality at high altitude was assessed by self-questionnaires in 16/16 subjects. All measurements were performed during at least 7h of sleep. Subjects were studied while sleeping at high altitude without (control, C) and with oxygen supplementation (FiO2=0.25, treated, T). Periodic breathing (%) C: 25±18 vs T: 6.6±5.6 (p<0.05), apneas index (no./h) C: 34.9±24.1 vs T: 8.5±6.8 (p<0.05); and sleep quality C: 17.8±3.4 vs T: 12.1±2.2 (p<0.0001) were evaluated. In conclusion, periodic breathing with apneas was present in miners exposed to high altitude for 1 to 4 years and was reduced by treatment with supplementary oxygen. PMID:25219448

  9. 14 CFR 135.93 - Autopilot: Minimum altitudes for use.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... minimum altitude engagement certification restriction; (2) The system is not engaged prior to the minimum engagement certification restriction specified in the Airplane Flight Manual, or an altitude specified by...

  10. Acute high-altitude illness: a clinically orientated review

    PubMed Central

    Smedley, Tom

    2013-01-01

    Acute high-altitude illness is an encompassing term for the range of pathology that the unacclimatised individual can develop at increased altitude. This includes acute mountain sickness, high-altitude cerebral oedema and high-altitude pulmonary oedema. These conditions represent an increasing clinical problem as more individuals are exposed to the hypobaric hypoxic environment of high altitude for both work and leisure. In this review of acute high-altitude illness, the epidemiology, risk factors and pathophysiology are explored, before their prevention and treatment are discussed. Appropriate ascent rate remains the most effective acute high-altitude illness prevention, with pharmacological prophylaxis indicated in selected individuals. Descent is the definitive treatment for acute high-altitude illness, with the adjuncts of oxygen and specific drug therapies. PMID:26516505

  11. DETAIL OF VACUUM PIPE OPENING WITHIN ALTITUDE CHAMBER R, FACING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF VACUUM PIPE OPENING WITHIN ALTITUDE CHAMBER R, FACING SOUTHEAST - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

  12. Selective and effective binding of pillar[5,6]arenes toward secondary ammonium salts with a weakly coordinating counteranion.

    PubMed

    Li, Chunju; Shu, Xiaoyan; Li, Jian; Fan, Jiazeng; Chen, Zhenxia; Weng, Linhong; Jia, Xueshun

    2012-08-17

    The selective and effective binding of secondary ammoniums with a weakly coordinating tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF) counteranion by per-ethylated pillar[5,6]arenes is reported. The construction of a first pillararene-based self-sorting system consisting of two wheels and two axles is also described. PMID:22866893

  13. Cyg X-1: A return to the pre-1971 intensity level and a 5.6-day modulation

    NASA Technical Reports Server (NTRS)

    Holt, S. S.; Kaluzienski, L. J.; Boldt, E. A.; Serlemitsos, P. J.

    1976-01-01

    Ariel-5 all sky monitor data on Cyg X-1 X-ray intensity increase during 1975 are analyzed. Data cover rise, maximum, and decay variability of the constellation. Special attention was given to the failure of the increase to decay over the specified period of 5.6 days.

  14. A Study on the Relationship between the Rhythm and Mathematics Skills of 5-6 Year Old Children

    ERIC Educational Resources Information Center

    Mertoglu, Ercan

    2010-01-01

    This is a relational scan study aiming to question the relationship between rhythm skills which are the most fundamental element in musical development and mathematics ability. Also within the general aims of the study is to examine whether this relationship varies with respect to the personal characteristics of 5-6 year olds. It has been…

  15. Lack of mutagenicity of the fungicide 2,4,5,6-tetrachloroisophthalonitrile in the Ames Salmonella/microsome test

    SciTech Connect

    Wei, C.I.

    1982-01-01

    The fungicide 2,4,5,6-tetrachloroisophthalonitrile, detected from a coal fly ash sample, was found to be not mutagenic to five Salmonella typhimurium tester strains. Incorporation of either a liver or a kidney activation system did not increase the mutagenic activity of the fungicide.

  16. Cs[H2NB2(C6F5)6] Featuring an Unequivocal 16-Coordinate Cation.

    PubMed

    Pollak, David; Goddard, Richard; Pörschke, Klaus-Richard

    2016-08-01

    Cesium bis(perfluoro-triphenylborane)amide, Cs[H2NB2(C6F5)6] (1), has been prepared by the reaction of sodium salt and CsF in dichloromethane and water. The compound is exceptional for a [H2NB2(C6F5)6](-) salt in that it contains a monatomic solute-free cation. Determination of the molecular structure revealed a novel C2 symmetrical conformation of the weakly coordinating [H2NB2(C6F5)6](-) anion, which gives rise to an unprecedented 16-coordinate (CN 16) Cs(+) cation in a likewise unprecedented tetracosahedral arrangement of F atoms. The poor solubility of 1 allows nearly quantitative separation of Cs(+) from water, which suggests potential applications as an effective (134/137)Cs remover from nuclear waste solutions, administration as an antidote for (134/137)Cs poisoning, and use for (131/137)Cs radiotherapy (brachytherapy). Rb[H2NB2(C6F5)6]·CH2Cl2 (2) has also been characterized, featuring two inequivalent Rb(+) cations having CN 10, one of which involves Rb(+)(η(2)-Cl2CH2)2 coordination. PMID:27267866

  17. 5-Bromo (or chloro)-6-azido-5,6-dihydro-2' -deoxyuridine and -thymidine derivatives with potent antiviral activity.

    PubMed

    Kumar, Rakesh

    2002-02-11

    Synthesis, antiviral, and cytotoxic activities of 5-bromo (or chloro)-6-azido-5,6-dihydro-2' -deoxyuridine (4,5) and -thymidine (6,7) are reported. Compounds 4 and 5 exhibited a broad spectrum of antiherpes activity against (HSV-1, HSV-2, HCMV, and VZV). PMID:11814776

  18. 77 FR 17386 - Significant New Use Rule for Hexabromocyclododecane and 1,2,5,6,9,10-Hexabromocyclododecane

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-26

    ...EPA is proposing a significant new use rule (SNUR) under section 5(a)(2) of the Toxic Substances Control Act (TSCA) for two chemical substances: Hexabromocyclododecane (Chemical Abstracts Service Registry Number (CASRN) 25637-99-4) and 1,2,5,6,9,10- hexabromocyclododecane (CASRN 3194-55-6), hereinafter collectively referred to as HBCD. This proposed rule would designate ``use in consumer......

  19. Stepping motor controller

    DOEpatents

    Bourret, S.C.; Swansen, J.E.

    1982-07-02

    A stepping motor is microprocessor controlled by digital circuitry which monitors the output of a shaft encoder adjustably secured to the stepping motor and generates a subsequent stepping pulse only after the preceding step has occurred and a fixed delay has expired. The fixed delay is variable on a real-time basis to provide for smooth and controlled deceleration.

  20. Stepping motor controller

    DOEpatents

    Bourret, Steven C.; Swansen, James E.

    1984-01-01

    A stepping motor is microprocessingly controlled by digital circuitry which monitors the output of a shaft encoder adjustably secured to the stepping motor and generates a subsequent stepping pulse only after the preceding step has occurred and a fixed delay has expired. The fixed delay is variable on a real-time basis to provide for smooth and controlled deceleration.

  1. Enzyme-assisted total synthesis of the optical antipodes D-myo-inositol 3,4,5-trisphosphate and D-myo-inositol 1,5, 6-trisphosphate: aspects of their structure-activity relationship to biologically active inositol phosphates.

    PubMed

    Adelt, S; Plettenburg, O; Stricker, R; Reiser, G; Altenbach, H J; Vogel, G

    1999-04-01

    Unambiguous total syntheses of both optical antipodes of the enantiomeric pair D-myo-inositol 3,4,5-trisphosphate (Ins(3,4,5)P3) and D-myo-inositol 1,5,6-trisphosphate (Ins(1,5,6)P3) are described. The ring system characteristic of myo-inositol was constructed de novo from p-benzoquinone. X-ray data for the enzymatically resolved (1S,2R,3R,4S)-1,4-diacetoxy-2,3-dibromocyclohex-5-ene enabled the unequivocal assignment of the absolute configuration. Subsequent transformations under stereocontrolled conditions led to enantiopure C2-symmetrical 1,4-(di-O-benzyldiphospho)conduritol B derivatives. Their synthetic potential was exploited to prepare Ins(3,4,5,6)P4 and Ins(1,4,5,6)P4 in three steps. With a recently identified and partially purified InsP5/InsP4 phosphohydrolase from Dictyostelium discoideum, these enantiomers could be converted to the target compounds, Ins(3,4,5)P3 and Ins(1,5,6)P3, on a preparative scale. An HPLC system employed for both purification of the inositol phosphates and analytical runs ensured that the products were isomerically homogeneous. The sensitivity of detection achieved by a complexometric postcolumn derivatization method indicates that the complexation properties of Ins(3,4,5)P3/Ins(1,5,6)P3 resemble those of Ins(1,2,3)P3, a compound with antioxidant potential. The set of inositol phosphates synthesized was used to clarify structural motifs important for molecular recognition by p42(IP4), a high-affinity Ins(1,3,4,5)P4/PtdIns(3,4,5)P3-specific binding protein from pig cerebellum. PMID:10197969

  2. Dust observations at orbital altitudes surrounding Mars

    NASA Astrophysics Data System (ADS)

    Andersson, L.; Weber, T. D.; Malaspina, D.; Crary, F.; Ergun, R. E.; Delory, G. T.; Fowler, C. M.; Morooka, M. W.; McEnulty, T.; Eriksson, A. I.; Andrews, D. J.; Horanyi, M.; Collette, A.; Yelle, R.; Jakosky, B. M.

    2015-11-01

    Dust is common close to the martian surface, but no known process can lift appreciable concentrations of particles to altitudes above ~150 kilometers. We present observations of dust at altitudes ranging from 150 to above 1000 kilometers by the Langmuir Probe and Wave instrument on the Mars Atmosphere and Volatile Evolution spacecraft. Based on its distribution, we interpret this dust to be interplanetary in origin. A comparison with laboratory measurements indicates that the dust grain size ranges from 1 to 12 micrometers, assuming a typical grain velocity of ~18 kilometers per second. These direct observations of dust entering the martian atmosphere improve our understanding of the sources, sinks, and transport of interplanetary dust throughout the inner solar system and the associated impacts on Mars’s atmosphere.

  3. HAWC - The High Altitude Water Cherenkov Detector

    NASA Astrophysics Data System (ADS)

    Tepe, Andreas; HAWC Collaboration

    2012-07-01

    The high altitude water Cherenkov observatory (HAWC) is an instrument for the detection of high energy cosmic gamma-rays. Its predecessor Milagro has successfully proven that the water Cherenkov technology for gamma-ray astronomy is a useful technique. HAWC is currently under construction at Sierra Negra in Mexico at an altitude of 4100 m and will include several improvements compared to Milagro. Two complementary DAQ systems of the HAWC detector allow for the observation of a large fraction of the sky with a very high duty cycle and independent of environmental conditions. HAWC will observe the gamma-ray sky from about 100 GeV up to 100 TeV. Also the cosmic ray flux anisotropy on different angular length scales is object of HAWC science. Because of HAWC's large effective area and field of view, we describe its prospects to observe gamma-ray bursts (GRBs) as an example for transient sources.

  4. High altitude plumes at Mars morning terminator

    NASA Astrophysics Data System (ADS)

    Sanchez-Lavega, A.; Garcia Muñoz, A.; Garcia Melendo, E.; Perez-Hoyos, S.; Gomez Forrellad, J. M.; Pellier, C.; Delcroix, M.; Lopez Valverde, M. A.; González Galindo, F.; Jaeschke, W.; Parker, D.; Phillips, J.; Peach, D.

    2015-10-01

    In March and April 2012 two extremely high altitude plumes were observed at the Martian terminator reaching 200 -250 km or more above the surface[1]. They were located at about 195o West longitude and 45o South latitude (at Terra Cimmeria) and extended ˜500 -1,000 km in both North-South and East- West, and lasted for about 10 days. Both plumes exhibited day-to-day variability, and were seen at the morning terminator but not at the evening limb. Another large plume was captured on Hubble Space Telescope images in May 1997 at 99º West longitude and 3º South latitude, but its altitude cannot be pr ecisely determined.Broad-band photometry was performed of both events in the spectral range 255 nm -1052 nm. Based on the observed properties, we discuss different possible scenarios for the mechanism responsible for the formation of these plumes.

  5. Antidiuretic hormone excretion at high altitude.

    PubMed

    Harber, M J; Williams, J D; Morton, J J

    1981-01-01

    Urinary excretion of electrolytes, creatinine, urea, and antidiuretic hormone--measured as arginine vasopressin (AVP) by radioimmunoassay--was investigated in eight Himalayan mountaineers during ascent on foot from 1900- 5400 m. Specimens were collected from each individual whenever urine was voided, preserved with 1% boric acid, and subsequently pooled to give samples representative of 24-h collections. AVP was found to be reasonably stable under simulated conditions of storage. In all subjects, the observed AVP excretion rates were mostly in the lower region of the normal range and there was generally no correlation with altitude, urine osmolality, electrolyte excretion, or occurrence of AMS symptoms--even in a fatal case of cerebral oedema. It is concluded that AVP does not play a primary role in the changes in fluid balance which accompany either acclimatization to high altitude or the onset of AMS. PMID:7213286

  6. The visual control of simulated altitude

    NASA Technical Reports Server (NTRS)

    Johnson, Walter W.; Bennett, C. Thomas; Tsang, Pamela S.; Phatak, Anil V.

    1987-01-01

    The ability of a subject flying an experimental flight to use the different sources of visual information by looking at the vertical tracking error was investigated using a 3 (altitude) x 3 (texture) x 2 (replication) factorial design. Each subject flew these 18 flights in the same partially counterbalanced order, constructed such that there was one flight at each of the three altitudes, and over each of the three surface textures within each successive set of three flights. The three ground-surface textures used consisted of meridian, latitudinal, and square textures described by Wolpert et al. (1983). The results showed that, in displays where only splay information was available, the subjects tended to confuse lateral motion with vertical.

  7. Dust observations at orbital altitudes surrounding Mars.

    PubMed

    Andersson, L; Weber, T D; Malaspina, D; Crary, F; Ergun, R E; Delory, G T; Fowler, C M; Morooka, M W; McEnulty, T; Eriksson, A I; Andrews, D J; Horanyi, M; Collette, A; Yelle, R; Jakosky, B M

    2015-11-01

    Dust is common close to the martian surface, but no known process can lift appreciable concentrations of particles to altitudes above ~150 kilometers. We present observations of dust at altitudes ranging from 150 to above 1000 kilometers by the Langmuir Probe and Wave instrument on the Mars Atmosphere and Volatile Evolution spacecraft. Based on its distribution, we interpret this dust to be interplanetary in origin. A comparison with laboratory measurements indicates that the dust grain size ranges from 1 to 12 micrometers, assuming a typical grain velocity of ~18 kilometers per second. These direct observations of dust entering the martian atmosphere improve our understanding of the sources, sinks, and transport of interplanetary dust throughout the inner solar system and the associated impacts on Mars's atmosphere. PMID:26542578

  8. Pulmonary Embolism in Young Natives of High Altitude.

    PubMed

    Singhal, Sanjay; Bhattachar, Srinivasa Alasinga; Paliwal, Vivek; Malhotra, Vineet Kumar; Addya, Kalyani; Kotwal, Atul

    2016-01-01

    Thrombotic events are relatively common in high altitude areas and known to occur in young soldiers working at high altitude without usual risk factors associated with thrombosis at sea-level. However, till now, cases with thrombotic events were reported only in lowlanders staying at high altitude. These two cases of pulmonary embolism demonstrate that thrombotic events can occur in highlanders after a prolonged stay at the extreme altitude. PMID:27512534

  9. Pulmonary Embolism in Young Natives of High Altitude

    PubMed Central

    Singhal, Sanjay; Bhattachar, Srinivasa Alasinga; Paliwal, Vivek; Malhotra, Vineet Kumar; Addya, Kalyani; Kotwal, Atul

    2016-01-01

    Thrombotic events are relatively common in high altitude areas and known to occur in young soldiers working at high altitude without usual risk factors associated with thrombosis at sea-level. However, till now, cases with thrombotic events were reported only in lowlanders staying at high altitude. These two cases of pulmonary embolism demonstrate that thrombotic events can occur in highlanders after a prolonged stay at the extreme altitude. PMID:27512534

  10. Observations from a constant-altitude stratospheric balloon

    NASA Technical Reports Server (NTRS)

    Mollo-Christensen, Erik; Vermillion, Charles H.; Chan, Paul H.; Mcbrien, Gary E.; Ward, William; Coronado, Patrick

    1991-01-01

    The paper describes a constant-altitude stratospheric balloon system, called Earthwinds, designed for high-altitude atmospheric observations. Special attention is given to the balloon's variable ballast system for altitude control; reactions of the balloon system to air motions in a stratified atmosphere; instruments for locating the balloon position, controlling the altitude, and making observations of atmospheric movements; balloon dynamics; and the atmospheric phenomena that will be observed by the balloon instruments.

  11. Altitude Compensating Nozzle Cold Flow Test Results

    NASA Technical Reports Server (NTRS)

    Ruf, J. H.; McDaniels, D. M.

    2002-01-01

    A suite of four altitude compensating nozzle (ACN) concepts were evaluated by NASA MSFC in the Nozzle Test Facility. The ACN concepts were a dual bell, a dual expander, an annular plug nozzle and an expansion deflection nozzle. Two reference bell nozzles were also tested. Axial thrust and nozzle wall static pressures were measured for each nozzle over a wide range of nozzle pressure ratios. The nozzle hardware and test program are described. Sample test results are presented.

  12. Renal adrenomedullin and high altitude diuresis.

    PubMed

    Haditsch, B; Roessler, A; Hinghofer-Szalkay, H G

    2007-01-01

    Previous investigations revealed that most of the fluid regulating hormones showed no consistent relationship to the hypoxic diuretic response (HDR). In this study we examined if adrenomedullin (AM), a hypoxia-mediated diuretic/natriuretic peptide is connected to HDR. Thirty-three persons were examined at low altitude (LA), on the third exposure day at 3440 m (medium altitude, MA) and on the fourteenth day at 5050 m (high altitude, HA). Nocturnal diuresis rose from 460 ml [interquartile range 302 ml] at LA to 560 [660] ml at MA to 1015 [750] ml at HA (p<0.005). Sodium excretion was similar at LA and MA (41.8 [27.0] vs. 41.4 [28.4] mM) and increased to 80.2 [29.1] mM at HA (p<0.005). Urinary AM excretion was 7.9 [3.9] at LA, 7.5 [5.7] pM at MA, and increased to 10.5 [5.1] pM (p<0.05) at HA. Urinary AM excretion was correlated to diuresis (r=0.72, p<0.005) and sodium excretion (r=0.57, p<0.005). Plasma AM concentration rose from 16.4 [3.1] to 18.8 [4.9] pM/l at MA (p<0.005) and to 18.3 [4.3] pM/l at HA (p<0.005). Plasma AM concentration and urinary AM excretion were not correlated, neither were plasma AM concentration and diuresis or natriuresis. Our data suggest the involvement of increased renal AM production in the pathophysiology of high altitude fluid and sodium loss. PMID:17087599

  13. Infrared reflectance of high altitude clouds.

    PubMed

    Hovis, W A; Blaine, L R; Forman, M L

    1970-03-01

    The spectral reflectance characteristics of cirrostratus, cirrus clouds, and a jet contrail, in the 0.68-2.4-micro spectral interval, are of interest for remote sensing of cloud types from orbiting satellites. Measurements made with a down-looking spectrometer from a high altitude aircraft show differences between the signatures of naturally formed ice clouds, a fresh jet contrail, and a snow covered surface. PMID:20076243

  14. Mitochondrial function at extreme high altitude.

    PubMed

    Murray, Andrew J; Horscroft, James A

    2016-03-01

    At high altitude, barometric pressure falls and with it inspired P(O2), potentially compromising O2 delivery to the tissues. With sufficient acclimatisation, the erythropoietic response increases red cell mass such that arterial O2 content (C(aO2)) is restored; however arterial P(O2)(P(aO2)) remains low, and the diffusion of O2 from capillary to mitochondrion is impaired. Mitochondrial respiration and aerobic capacity are thus limited, whilst reactive oxygen species (ROS) production increases. Restoration of P(aO2) with supplementary O2 does not fully restore aerobic capacity in acclimatised individuals, possibly indicating a peripheral impairment. With prolonged exposure to extreme high altitude (>5500 m), muscle mitochondrial volume density falls, with a particular loss of the subsarcolemmal population. It is not clear whether this represents acclimatisation or deterioration, but it does appear to be regulated, with levels of the mitochondrial biogenesis factor PGC-1α falling, and shows similarities to adapted Tibetan highlanders. Qualitative changes in mitochondrial function also occur, and do so at more moderate high altitudes with shorter periods of exposure. Electron transport chain complexes are downregulated, possibly mitigating the increase in ROS production. Fatty acid oxidation capacity is decreased and there may be improvements in biochemical coupling at the mitochondrial inner membrane that enhance O2 efficiency. Creatine kinase expression falls, possibly impairing high-energy phosphate transfer from the mitochondria to myofibrils. In climbers returning from the summit of Everest, cardiac energetic reserve (phosphocreatine/ATP) falls, but skeletal muscle energetics are well preserved, possibly supporting the notion that mitochondrial remodelling is a core feature of acclimatisation to extreme high altitude. PMID:26033622

  15. The High Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    Mostafa, Miguel; HAWC Collaboration

    2016-03-01

    The High Altitude Water Cherenkov (HAWC) Observatory is a continuously operated, wide field of view experiment comprised of an array of 300 water Cherenkov detectors (WCDs) to study transient and steady emission of TeV gamma and cosmic rays. Each 200000 l WCD is instrumented with 4 PMTs providing charge and timing information. The array covers ~22000 m2 at an altitude of 4100 m a.s.l. inside the Pico de Orizaba national park in Mexico. The high altitude, large active area, and optical isolation of the PMTs allows us to reliably estimate the energy and determine the arrival direction of gamma and cosmic rays with significant sensitivity over energies from several hundred GeV to a hundred TeV. Continuously observing 2 / 3 of the sky every 24 h, HAWC plays a significant role as a survey instrument for multi-wavelength studies. The performance of HAWC makes possible the detection of both transient and steady emissions, the study of diffuse emission and the measurement of the spectra of gamma-ray sources at TeV energies. HAWC is also sensitive to the emission from GRBs above 100 GeV. I will highlight the results from the first year of operation of the full HAWC array, and describe the ongoing site work to expand the array by a factor of 4 to explore the high energy range.

  16. Use of ultrasound in altitude decompression modeling

    NASA Technical Reports Server (NTRS)

    Olson, Robert M.; Pilmanis, Andrew A.

    1993-01-01

    A model that predicts the probability of developing decompression sickness (DCS) with various denitrogenation schedules is being developed by the Armstrong Laboratory, using human data from previous exposures. It was noted that refinements are needed to improve the accuracy and scope of the model. A commercially developed ultrasonic echo imaging system is being used in this model development. Using this technique, bubbles images from a subject at altitude can be seen in the gall bladder, hepatic veins, vena cava, and chambers of the heart. As judged by their motion and appearance in the vena cava, venous bubbles near the heart range in size from 30 to 300 M. The larger bubbles skim along the top, whereas the smaller ones appear as faint images near the bottom of the vessel. Images from growing bubbles in a model altitude chamber indicate that they grow rapidly, going from 20 to 100 M in 3 sec near 30,000 ft altitude. Information such as this is valuable in verifying those aspects of the DCS model dealing with bubble size, their growth rate, and their site of origin.

  17. A Challenge to the Highest Balloon Altitude

    NASA Astrophysics Data System (ADS)

    Saito, Yoshitaka; Akita, Daisuke; Fuke, Hideyuki; Iijima, Issei; Izutsu, Naoki; Kato, Yoichi; Kawada, Jiro; Matsuzaka, Yukihiko; Mizuta, Eiichi; Namiki, Michiyoshi; Nonaka, Naoki; Ohta, Shigeo; Sato, Takatoshi; Seo, Motoharu; Takada, Atsushi; Tamura, Keisuke; Toriumi, Michihiko; Yamagami, Takamasa; Yamada, Kazuhiko; Yoshida, Tetsuya; Matsushima, Kiyoho; Tanaka, Shigeki

    Development of a balloon to fly at higher altitudes is one of the most attractive challenges in scientific balloon technologies. After reaching the highest record setting balloon altitude of 53.0 km using the 3.4 µm film in 2002, a thinner balloon film with a thickness of 2.8 µm using a higher density resin was developed. In 2004, a 5,000 m3 balloon with the film was successfully launched, however, 60,000 m3 balloons launched in 2005, 2006, and 2007, were broken during the ascending phase. The problem was suspected to be due to the properties of the film including the uniformity and the strength, neither of which can be estimated by the conventional tensile test. Thus, we checked the strength of the film with large sample, the bi-axial tensile test properties, the creep properties, and the viscoelasticity, comparing with these to the other thick balloon films. In this conference, we are going to report our new test procedure of the balloon film, results of our current and a new 2.8 µm balloon film, and our future plan to launch the highest altitude balloon.

  18. Altitude and arteriolar hyalinosis after kidney transplantation.

    PubMed

    Cippà, Pietro E; Grebe, Scott O; Fehr, Thomas; Wüthrich, Rudolf P; Mueller, Thomas F

    2016-09-01

    The kidney is very susceptible to hypoxic injury. Calcineurin inhibitors (CNIs) induce vasoconstriction and might reduce renal tissue oxygenation. We aimed to investigate if the synergistic deleterious effects of CNI-treatment and hypoxia of high altitude living might accelerate the development of arteriolar hyalinosis in kidney allografts. We stratified all patients who received a kidney graft from 2000 to 2010 in our centre (n = 477) in three groups according to the residential elevation (below 400, between 400 to 600 and above 600 m above sea level) and we retrospectively re-evaluated all transplant biopsies performed during follow-up, specifically looking at the degree of arteriolar hyalinosis, the hallmark of chronic CNI nephrotoxicity. Living at high altitude was markedly associated with a higher degree of arteriolar hyalinosis (P < 0.001). Haemoglobin levels confirmed the functional relevance of different arterial oxygenation among the groups (P = 0.01). Thus, patients living at high altitude seem to be more susceptible to the development of arteriolar hyalinosis after kidney transplantation. PMID:26823025

  19. Exhausted Plume Flow Field Prediction Near the Afterbody of Hypersonic Flight Vehicles in High Altitudes

    NASA Technical Reports Server (NTRS)

    Chou, Lynn Chen; Mach, Kervyn D.; Deng, Zheng-Tao; Liaw, Goang-Shin

    1995-01-01

    A two-dimensional computer code to solve the Burnett equations has been developed which computes the flow interaction between an exhausted plume and hypersonic external flow near the afterbody of a flight vehicle. This Burnett-2D code extends the capability of Navier-Stokes solver (RPLUS2D code) to include high-order Burnett source terms and slip-wall conditions for velocity and temperature. Higher-order Burnett viscous stress and heat flux terms are discretized using central-differencing and treated as source terms. Blocking logic is adopted in order to overcome the difficulty of grid generation. The computation of exhaust plume flow field is divided into two steps. In the first step, the thruster nozzle exit conditions are computed which generates inflow conditions in the base area near the afterbody. Results demonstrated that at high altitudes, the computations of nozzle exit conditions must include the effects of base flow since significant expansion exists in the base region. In the second step, Burnett equations were solved for exhaust plume flow field near the afterbody. The free stream conditions are set at an altitude equal to 80km and the Mach number is equal to 5.0. The preliminary results show that the plume expansion, as altitude increases, will eventually cause upstream flow separation.

  20. Human Behaviour and Development under High-Altitude Conditions

    ERIC Educational Resources Information Center

    Virues-Ortega, Javier; Garrido, Eduardo; Javierre, Casimiro; Kloezeman, Karen C.

    2006-01-01

    Although we are far from a universally accepted pattern of impaired function at altitude, there is evidence indicating motor, perceptual, memory and behavioural deficits in adults. Even relatively low altitudes (2500 m) may delay reaction time, and impair motor function. Extreme altitude exposure (greater than 5000 m) may result in more pronounced…

  1. Detection of ocean color changes from high altitudes

    NASA Technical Reports Server (NTRS)

    Hovis, W. A.; Forman, M. L.; Blaine, L. R.

    1973-01-01

    The detection of ocean color changes, thought to be due to chlorophyll concentrations and gelbstoffe variations, is attempted from high altitude (11.3km) and low altitude (0.3km). The atmospheric back scattering is shown to reduce contrast, but not sufficiently to obscure color change detection at high altitudes.

  2. MoARG1, MoARG5,6 and MoARG7 involved in arginine biosynthesis are essential for growth, conidiogenesis, sexual reproduction, and pathogenicity in Magnaporthe oryzae.

    PubMed

    Zhang, Yong; Shi, Huanbin; Liang, Shuang; Ning, Guoao; Xu, Nanchang; Lu, Jianping; Liu, Xiaohong; Lin, Fucheng

    2015-11-01

    Arginine is one of the most versatile amino acids in eukaryote cells, which plays important roles in a multitude of processes such as protein synthesis, nitrogen metabolism, nitric oxide (NO) and urea biosynthesis. The de novo arginine biosynthesis pathway is conserved among fungal kingdom, but poorly understood in plant pathogenic fungi. Here, we characterized the functions of three synthetic enzyme-encoding genes MoARG1, MoARG5,6, and MoARG7, which involved the seventh step, second-third step and fifth step of arginine biosynthesis in Magnaporthe oryzae, respectively. Deletion of MoARG1 or MoARG5,6, resulted in arginine auxotrophic mutants, which had a strict requirement for arginine on minimal medium (MM). Both ΔMoarg1 and ΔMoarg5,6 severely reduced in aerial hyphal growth, pigmentation, conidiogenesis, sexual reproduction and pathogenicity. Interestingly, like Saccharomyces cerevisiae, deletion of MoARG7 caused a leaky arginine auxotrophy, and attenuated pathogenicity. Limited appressorium-mediated penetration and restricted invasive hyphae growth in host cells are responsible for the severely attenuated pathogenicity of the Arg(-) mutants. Additionally, we monitored the NO generation during conidial germination and appressorial formation in both Arg(-) mutants and wild type, and demonstrated that NO generation may not occur via arginine-dependent pathway in M. oryzae. In summary, MoARG1, MoARG5,6, and MoARG7 are required for growth, conidiogenesis, sexual reproduction, and pathogenicity in M. oryzae. PMID:26505307

  3. Carbohydrate supplementation and exercise performance at high altitude: a randomized controlled trial.

    PubMed

    Oliver, Samuel J; Golja, Petra; Macdonald, Jamie H

    2012-03-01

    Acute carbohydrate supplementation decreases effort perception and increases endurance exercise capacity at sea level. It also improves laboratory-based endurance performance at altitude. However, the effect of chronic carbohydrate supplementation at altitude, when acclimatization may attenuate carbohydrate effects, achieved doses are lower and metabolic effects may be different, is unknown and was therefore focused on in the present study. Forty-one members of a 22-day high altitude expedition were randomized in a double-blind design to receive either placebo or carbohydrate supplementation. Diet was manipulated with commercially available energy drinks consumed ad libitum throughout the expedition. Participants performed a mountaineering time trial at 5192 m, completed submaximal incremental exercise step tests to assess cardiovascular parameters before, during, and after the expedition, and recorded spontaneous physical activity by accelerometer on rest days. Compared to placebo, compliant individuals of the carbohydrate-supplemented group received daily an additional 3.5±1.4 g carbohydrate·kg body mass(-1). Compliant individuals of the carbohydrate supplemented group reported 18% lower ratings of perceived exertion during the time trial at altitude, and completed it 17% faster than the placebo group (both p<0.05 by t-test). However, cardiovascular parameters obtained during submaximal exercise and spontaneous physical activity on rest days were similar between the two groups (all p>0.05 by analysis of variance). This study utilized testing protocols of specific relevance to high altitude sojourners, including the highest mountaineering time trial completed to date at altitude. Chronic carbohydrate supplementation reduced ratings of perceived exertion and improved physical performance, especially during prolonged and higher intensity exercise tasks. PMID:22429229

  4. Global Trends in Glacial Cirque Floor Altitudes and Their Relationships with Climate, Equilibrium Line Altitudes, and Mountain Range Heights

    NASA Astrophysics Data System (ADS)

    Mitchell, S. G.; Humphries, E.

    2013-12-01

    Glacial erosion at the base of cirque headwalls and the creation of threshold slopes above cirque floors may contribute to the 'glacial buzzsaw' effect in limiting the altitude of some mountain ranges. Since glacial extent and therefore glacial erosion rate depends on the equilibrium line altitude (ELA) of a region, the altitude of cirque formation should be a function of the ELA. Several regional studies have shown that cirque floors form at an altitude approximating average Quaternary ELAs in some mountain ranges, but a global correlation has not yet been demonstrated. We examined the correlation between cirque altitudes and global ELA trends by compiling existing and new cirque altitude and morphometry data from > 30 mountain ranges at a wide range of latitudes. Where available, we calculate or present the average cirque altitude, relief, and latitude. We compared these altitudes to both the global East Pacific ELA and local ELAs where available. For the locations analyzed, the majority of average cirque altitudes fall between the Eastern Pacific modern and LGM ELAs, and mountain range height is typically limited to < 600 m above that altitude. This evidence supports the hypothesis that cirque formation is dependent upon the ELA, and that cirques likely form as a result of average, rather than extreme, glacial conditions. Furthermore, the correlation between cirque altitude and ELA, along with the restricted window of relief, implies that cirque formation is a factor in limiting peak altitude in ranges that rise above the ELA.

  5. High altitude pulmonary oedema (HAPE) in an Indian pilgrim.

    PubMed

    Panthi, Sagar; Basnyat, Buddha

    2013-11-01

    Increasing number of Hindu pilgrims visit the Himalayas where some of them suffer from high altitude illness including the life threatening forms, high altitude pulmonary oedema (HAPE) and high altitude cerebral oedema. Compared to tourists and trekkers, pilgrims are usually ignorant about altitude illness. This is a case of a pilgrim who suffered from HAPE on his trip to Kailash-Mansarovar and is brought to a tertiary level hospital in Kathmandu. This report emphasises on how to treat a patient with HAPE, a disease which is increasingly being seen in the high altitude pilgrim population. PMID:24974506

  6. Aerodynamics of heat exchangers for high-altitude aircraft

    NASA Technical Reports Server (NTRS)

    Drela, Mark

    1996-01-01

    Reduction of convective beat transfer with altitude dictates unusually large beat exchangers for piston- engined high-altitude aircraft The relatively large aircraft drag fraction associated with cooling at high altitudes makes the efficient design of the entire heat exchanger installation an essential part of the aircraft's aerodynamic design. The parameters that directly influence cooling drag are developed in the context of high-altitude flight Candidate wing airfoils that incorporate heat exchangers are examined. Such integrated wing-airfoil/heat-exchanger installations appear to be attractive alternatives to isolated heat.exchanger installations. Examples are drawn from integrated installations on existing or planned high-altitude aircraft.

  7. Synthesis of S-(-)-5,6-Dihydrocanthin-4-ones via a Triple Cooperative Catalysis-Mediated Domino Reaction.

    PubMed

    Dighe, Shashikant U; Mahar, Rohit; Shukla, Sanjeev K; Kant, Ruchir; Srivastava, Kumkum; Batra, Sanjay

    2016-06-01

    An enantioselective synthesis of S-(-)-5,6-dihydrocanthin-4-ones via a triple cooperative catalysis-mediated domino reaction having a broad substrate scope is reported. The reaction between substituted 1-formyl-9H-β-carbolines and terminal alkynes in the presence of catalytic amounts of Jorgensen-Hayashi catalyst, copper iodide, and Hunig base proceeded via a multicascade route, affording the title compounds in good yields and excellent ees with interesting mechanistic features. These compounds were assessed for in vitro antiplasmodial activity against P. falciparum strains. Additionally, 5,6-dihydrocanthin-4-ones are demonstrated to be a versatile precursor to different fused β-carboline derivatives via simple synthetic transformations. PMID:27159615

  8. Polarization Components in π0 Photoproduction at Photon Energies up to 5.6 GeV

    NASA Astrophysics Data System (ADS)

    Luo, W.; Brash, E. J.; Gilman, R.; Jones, M. K.; Meziane, M.; Pentchev, L.; Perdrisat, C. F.; Puckett, A. J. R.; Punjabi, V.; Wesselmann, F. R.; Ahmidouch, A.; Albayrak, I.; Aniol, K. A.; Arrington, J.; Asaturyan, A.; Ates, O.; Baghdasaryan, H.; Benmokhtar, F.; Bertozzi, W.; Bimbot, L.; Bosted, P.; Boeglin, W.; Butuceanu, C.; Carter, P.; Chernenko, S.; Christy, M. E.; Commisso, M.; Cornejo, J. C.; Covrig, S.; Danagoulian, S.; Daniel, A.; Davidenko, A.; Day, D.; Dhamija, S.; Dutta, D.; Ent, R.; Frullani, S.; Fenker, H.; Frlez, E.; Garibaldi, F.; Gaskell, D.; Gilad, S.; Goncharenko, Y.; Hafidi, K.; Hamilton, D.; Higinbotham, D. W.; Hinton, W.; Horn, T.; Hu, B.; Huang, J.; Huber, G. M.; Jensen, E.; Kang, H.; Keppel, C.; Khandaker, M.; King, P.; Kirillov, D.; Kohl, M.; Kravtsov, V.; Kumbartzki, G.; Li, Y.; Mamyan, V.; Margaziotis, D. J.; Markowitz, P.; Marsh, A.; Matulenko, Y.; Maxwell, J.; Mbianda, G.; Meekins, D.; Melnik, Y.; Miller, J.; Mkrtchyan, A.; Mkrtchyan, H.; Moffit, B.; Moreno, O.; Mulholland, J.; Narayan, A.; Nuruzzaman; Nedev, S.; Piasetzky, E.; Pierce, W.; Piskunov, N. M.; Prok, Y.; Ransome, R. D.; Razin, D. S.; Reimer, P. E.; Reinhold, J.; Rondon, O.; Shabestari, M.; Shahinyan, A.; Shestermanov, K.; Širca, S.; Sitnik, I.; Smykov, L.; Smith, G.; Solovyev, L.; Solvignon, P.; Strakovsky, I. I.; Subedi, R.; Suleiman, R.; Tomasi-Gustafsson, E.; Vasiliev, A.; Veilleux, M.; Wood, S.; Ye, Z.; Zanevsky, Y.; Zhang, X.; Zhang, Y.; Zheng, X.; Zhu, L.

    2012-06-01

    We present new data for the polarization observables of the final state proton in the H1(γ→,p→)π0 reaction. These data can be used to test predictions based on hadron helicity conservation and perturbative QCD. These data have both small statistical and systematic uncertainties and were obtained with beam energies between 1.8 and 5.6 GeV and for π0 scattering angles larger than 75° in the center-of-mass frame. The data extend the polarization measurements database for neutral pion photoproduction up to Eγ=5.6GeV. The results show a nonzero induced polarization above the resonance region. The polarization transfer components vary rapidly with the photon energy and π0 scattering angle in the center-of-mass frame. This indicates that hadron helicity conservation does not hold and that the perturbative QCD limit is still not reached in the energy regime of this experiment.

  9. Antimalarial 5,6-Dihydro-α-pyrones from Cryptocarya rigidifolia: Related Bicyclic Tetrahydro-α-Pyrones Are Artifacts1

    PubMed Central

    2016-01-01

    Antimalarial bioassay-guided fractionation of an EtOH extract of the root wood of Cryptocarya rigidifolia (Lauraceae) led to the isolation of the five new 5,6-dihydro-α-pyrones cryptorigidifoliols A–E (1–5) and the six bicyclic tetrahydro-α-pyrone derivatives cryptorigidifoliols F–K (6–11). The structure elucidations of all compounds were made on the basis of the interpretation of spectroscopic data and chemical derivatization, and the relative and absolute configurations were determined by NOESY, electronic circular dichroism (ECD), and 1H NMR analysis of α-methoxyphenylacetyl (MPA) derivatives. The bicyclic tetrahydro-α-pyrone derivatives were identified as products of acid-catalyzed intramolecular Michael addition of the 5,6-dihydro-α-pyrones in the presence of silica gel. A structure–activity relationship study suggested that the presence of an α,β-unsaturated carbonyl moiety is not essential for potent antimalarial activity. PMID:26042470

  10. Growth among Tibetans at high and low altitudes in India.

    PubMed

    Tripathy, Vikal; Gupta, Ranjan

    2007-01-01

    In India, Tibetans have been living at different altitudes for more than 40 years. This study describes physical growth in terms of height, weight, sitting height, skinfold thickness at triceps and upper arm circumference of Tibetans born and raised at three Tibetan refugee settlements (3,521; 970; and 800 m) from the view point of the hypothesis that growth is retarded at high altitude. Samples consist of individuals between the ages of 2 and 40 years. Tibetans at high altitude in India show a growth pattern similar to that previously observed among Tibetans in Tibet. Tibetans at high altitude are taller and heavier compared to Andean highlanders. The general trends show that Tibetan children and adults of both sexes at low altitude in India are advanced in terms of height, weight, skinfold thickness at triceps and upper arm circumference compared to Tibetans at high altitude. Trunk length (sitting height) is similar at the two altitudes but relative sitting height is greater at high altitude. Greater relative sitting height and lesser leg length at high altitude than at low altitudes is discussed in terms of effect of altitude, temperature, and nutritional status. PMID:17691098

  11. High-Altitude Illnesses: Physiology, Risk Factors, Prevention, and Treatment

    PubMed Central

    Taylor, Andrew T.

    2011-01-01

    High-altitude illnesses encompass the pulmonary and cerebral syndromes that occur in non-acclimatized individuals after rapid ascent to high altitude. The most common syndrome is acute mountain sickness (AMS) which usually begins within a few hours of ascent and typically consists of headache variably accompanied by loss of appetite, nausea, vomiting, disturbed sleep, fatigue, and dizziness. With millions of travelers journeying to high altitudes every year and sleeping above 2,500 m, acute mountain sickness is a wide-spread clinical condition. Risk factors include home elevation, maximum altitude, sleeping altitude, rate of ascent, latitude, age, gender, physical condition, intensity of exercise, pre-acclimatization, genetic make-up, and pre-existing diseases. At higher altitudes, sleep disturbances may become more profound, mental performance is impaired, and weight loss may occur. If ascent is rapid, acetazolamide can reduce the risk of developing AMS, although a number of high-altitude travelers taking acetazolamide will still develop symptoms. Ibuprofen can be effective for headache. Symptoms can be rapidly relieved by descent, and descent is mandatory, if at all possible, for the management of the potentially fatal syndromes of high-altitude pulmonary and cerebral edema. The purpose of this review is to combine a discussion of specific risk factors, prevention, and treatment options with a summary of the basic physiologic responses to the hypoxia of altitude to provide a context for managing high-altitude illnesses and advising the non-acclimatized high-altitude traveler. PMID:23908794

  12. NLRP3 deletion protects against renal fibrosis and attenuates mitochondrial abnormality in mouse with 5/6 nephrectomy.

    PubMed

    Gong, Wei; Mao, Song; Yu, Jing; Song, Jiayu; Jia, Zhanjun; Huang, Songming; Zhang, Aihua

    2016-05-15

    Progressive fibrosis in chronic kidney disease (CKD) is the well-recognized cause leading to the progressive loss of renal function. Emerging evidence indicated a pathogenic role of the NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome in mediating kidney injury. However, the role of NLRP3 in the remnant kidney disease model is still undefined. The present study was undertaken to evaluate the function of NLRP3 in modulating renal fibrosis in a CKD model of 5/6 nephrectomy (5/6 Nx) and the potential involvement of mitochondrial dysfunction in the pathogenesis. Employing NLRP3(+/+) and NLRP3(-/-) mice with or without 5/6 Nx, we examined renal fibrotic response and mitochondrial function. Strikingly, tubulointerstitial fibrosis was remarkably attenuated in NLRP3(-/-) mice as evidenced by the blockade of extracellular matrix deposition. Meanwhile, renal tubular cells in NLRP3(-/-) mice maintained better mitochondrial morphology and higher mitochondrial DNA copy number, indicating an amelioration of mitochondrial abnormality. Moreover, NLRP3 deletion also blunted the severity of proteinuria and CKD-related hypertension. To further evaluate the direct role of NLRP3 in triggering fibrogenesis, mouse proximal tubular cells (PTCs) were subjected to transforming growth factor β1 (TGF-β1), and the cellular phenotypic changes were detected. As expected, TGF-β1-induced alterations of PTC phenotype were abolished by NLRP3 small interfering RNA, in line with a protection of mitochondrial function. Taken together, NLRP3 deletion protected against renal fibrosis in the 5/6 Nx disease model, possibly via inhibiting mitochondrial dysfunction. PMID:26887832

  13. Euphorikanin A, a Diterpenoid Lactone with a Fused 5/6/7/3 Ring System from Euphorbia kansui.

    PubMed

    Fei, Dong-Qing; Dong, Le-Le; Qi, Feng-Ming; Fan, Gai-Xia; Li, Hui-Hong; Li, Zheng-Yu; Zhang, Zhan-Xin

    2016-06-17

    Euphorikanin A (1), an unprecedented diterpenoid lactone which possesses a novel 5/6/7/3-fused tetracyclic ring skeleton, was isolated from the roots of Euphorbia kansui. The chemical structure and absolute stereochemistry were elucidated on the basis of extensive spectroscopic methods and single-crystal X-ray diffraction analysis. Compound 1 exhibited moderate cytotoxicity against two human tumor cell lines HeLa and NCI-446. A proposed biosynthetic pathway of compound 1 is also described. PMID:27230557

  14. Glucose intolerance associated with hypoxia in people living at high altitudes in the Tibetan highland

    PubMed Central

    Okumiya, Kiyohito; Sakamoto, Ryota; Ishimoto, Yasuko; Kimura, Yumi; Fukutomi, Eriko; Ishikawa, Motonao; Suwa, Kuniaki; Imai, Hissei; Chen, Wenling; Kato, Emiko; Nakatsuka, Masahiro; Kasahara, Yoriko; Fujisawa, Michiko; Wada, Taizo; Wang, Hongxin; Dai, Qingxiang; Xu, Huining; Qiao, Haisheng; Ge, Ri-Li; Norboo, Tsering; Tsering, Norboo; Kosaka, Yasuyuki; Nose, Mitsuhiro; Yamaguchi, Takayoshi; Tsukihara, Toshihiro; Ando, Kazuo; Inamura, Tetsuya; Takeda, Shinya; Ishine, Masayuki; Otsuka, Kuniaki; Matsubayashi, Kozo

    2016-01-01

    Objectives To clarify the association between glucose intolerance and high altitudes (2900–4800 m) in a hypoxic environment in Tibetan highlanders and to verify the hypothesis that high altitude dwelling increases vulnerability to diabetes mellitus (DM) accelerated by lifestyle change or ageing. Design Cross-sectional epidemiological study on Tibetan highlanders. Participants We enrolled 1258 participants aged 40–87 years. The rural population comprised farmers in Domkhar (altitude 2900–3800 m) and nomads in Haiyan (3000–3100 m), Ryuho (4400 m) and Changthang (4300–4800 m). Urban area participants were from Leh (3300 m) and Jiegu (3700 m). Main outcome measure Participants were classified into six glucose tolerance-based groups: DM, intermediate hyperglycaemia (IHG), normoglycaemia (NG), fasting DM, fasting IHG and fasting NG. Prevalence of glucose intolerance was compared in farmers, nomads and urban dwellers. Effects of dwelling at high altitude or hypoxia on glucose intolerance were analysed with the confounding factors of age, sex, obesity, lipids, haemoglobin, hypertension and lifestyle, using multiple logistic regression. Results The prevalence of DM (fasting DM)/IHG (fasting IHG) was 8.9% (6.5%)/25.1% (12.7%), respectively, in all participants. This prevalence was higher in urban dwellers (9.5% (7.1%)/28.5% (11.7%)) and in farmers (8.5% (6.1%)/28.5% (18.3%)) compared with nomads (8.2% (5.7%)/15.7% (9.7%)) (p=0.0140/0.0001). Dwelling at high altitude was significantly associated with fasting IHG+fasting DM/fasting DM (ORs for >4500 and 3500–4499 m were 3.59/4.36 and 2.07/1.76 vs <3500 m, respectively). After adjusting for lifestyle change, hypoxaemia and polycythaemia were closely associated with glucose intolerance. Conclusions Socioeconomic factors, hypoxaemia and the effects of altitudes >3500 m play a major role in the high prevalence of glucose intolerance in highlanders. Tibetan highlanders may be vulnerable to glucose

  15. Dose-response of altitude training: how much altitude is enough?

    PubMed

    Levine, Benjamin D; Stray-Gundersen, James

    2006-01-01

    Altitude training continues to be a key adjunctive aid for the training of competitive athletes throughout the world. Over the past decade, evidence has accumulated from many groups of investigators that the "living high--training low" approach to altitude training provides the most robust and reliable performance enhancements. The success of this strategy depends on two key features: 1) living high enough, for enough hours per day, for a long enough period of time, to initiate and sustain an erythropoietic effect of high altitude; and 2) training low enough to allow maximal quality of high intensity workouts, requiring high rates of sustained oxidative flux. Because of the relatively limited access to environments where such a strategy can be practically applied, numerous devices have been developed to "bring the mountain to the athlete," which has raised the key issue of the appropriate "dose" of altitude required to stimulate an acclimatization response and performance enhancement. These include devices using molecular sieve technology to provide a normobaric hypoxic living or sleeping environment, approaches using very high altitudes (5,500m) for shorter periods of time during the day, and "intermittent hypoxic training" involving breathing very hypoxic gas mixtures for alternating 5 minutes periods over the course of 60-90 minutes. Unfortunately, objective testing of the strategies employing short term (less than 4 hours) normobaric or hypobaric hypoxia has failed to demonstrate an advantage of these techniques. Moreover individual variability of the response to even the best of living high--training low strategies has been great, and the mechanisms behind this variability remain obscure. Future research efforts will need to focus on defining the optimal dosing strategy for these devices, and determining the underlying mechanisms of the individual variability so as to enable the individualized "prescription" of altitude exposure to optimize the performance of

  16. A Combined Experimental and Theoretical Approach to the Photogeneration of 5,6-Dihydropyrimidin-5-yl Radicals in Nonaqueous Media.

    PubMed

    Aparici-Espert, Isabel; Francés-Monerris, Antonio; Rodríguez-Muñiz, Gemma M; Roca-Sanjuán, Daniel; Lhiaubet-Vallet, Virginie; Miranda, Miguel A

    2016-05-20

    The chemical fate of radical intermediates is relevant to understand the biological effects of radiation and to explain formation of DNA lesions. A direct approach to selectively generate the putative reactive intermediates is based on the irradiation of photolabile precursors. But, to date, radical formation and reactivity have only been studied in aqueous media, which do not completely mimic the microenvironment provided by the DNA structure and its complexes with proteins. Thus, it is also important to evaluate the photogeneration of nucleoside-based radicals in nonaqueous media. The attention here is focused on the independent generation of 5,6-dihydropyrimidin-5-yl radicals in organic solvent through the synthesis of new lipophilic tert-butyl ketone precursors. Formation of 5,6-dihydro-2'-deoxyuridin-5-yl and 5,6-dihydrothymidin-5-yl radicals has first been confirmed by using a new nitroxide-derived profluorescent radical trap. Further evidence has been obtained by nanosecond laser flash photolysis through detection of long-lived transients. Finally, the experimental data are corroborated by multiconfigurational ab initio CASPT2//CASSCF methodology. PMID:27088245

  17. Structure and functional properties of Norrin mimic Wnt for signalling with Frizzled4, Lrp5/6, and proteoglycan

    PubMed Central

    Chang, Tao-Hsin; Hsieh, Fu-Lien; Zebisch, Matthias; Harlos, Karl; Elegheert, Jonathan; Jones, E Yvonne

    2015-01-01

    Wnt signalling regulates multiple processes including angiogenesis, inflammation, and tumorigenesis. Norrin (Norrie Disease Protein) is a cystine-knot like growth factor. Although unrelated to Wnt, Norrin activates the Wnt/β-catenin pathway. Signal complex formation involves Frizzled4 (Fz4), low-density lipoprotein receptor related protein 5/6 (Lrp5/6), Tetraspanin-12 and glycosaminoglycans (GAGs). Here, we report crystallographic and small-angle X-ray scattering analyses of Norrin in complex with Fz4 cysteine-rich domain (Fz4CRD), of this complex bound with GAG analogues, and of unliganded Norrin and Fz4CRD. Our structural, biophysical and cellular data, map Fz4 and putative Lrp5/6 binding sites to distinct patches on Norrin, and reveal a GAG binding site spanning Norrin and Fz4CRD. These results explain numerous disease-associated mutations. Comparison with the Xenopus Wnt8–mouse Fz8CRD complex reveals Norrin mimics Wnt for Frizzled recognition. The production and characterization of wild-type and mutant Norrins reported here open new avenues for the development of therapeutics to combat abnormal Norrin/Wnt signalling. DOI: http://dx.doi.org/10.7554/eLife.06554.001 PMID:26158506

  18. Steps in Behavior Modividation.

    ERIC Educational Resources Information Center

    Straughan, James H.; And Others

    James H. Straughan lists five steps for modifying target behavior and four steps for working with teachers using behavior modification. Grant Martin and Harold Kunzelmann then outline an instructional program for pinpointing and recording classroom behaviors. (JD)

  19. Altitude Testing of Large Liquid Propellant Engines

    NASA Technical Reports Server (NTRS)

    Maynard, Bryon T.; Raines, Nickey G.

    2010-01-01

    The National Aeronautics and Space Administration entered a new age on January 14, 2004 with President Bush s announcement of the creation the Vision for Space Exploration that will take mankind back to the Moon and on beyond to Mars. In January, 2006, after two years of hard, dedicated labor, engineers within NASA and its contractor workforce decided that the J2X rocket, based on the heritage of the Apollo J2 engine, would be the new engine for the NASA Constellation Ares upper stage vehicle. This engine and vehicle combination would provide assured access to the International Space Station to replace that role played by the Space Shuttle and additionally, would serve as the Earth Departure Stage, to push the Crew Excursion Vehicle out of Earth Orbit and head it on a path for rendezvous with the Moon. Test as you fly, fly as you test was chosen to be the guiding philosophy and a pre-requisite for the engine design, development, test and evaluation program. An exhaustive survey of national test facility assets proved the required capability to test the J2X engine at high altitude for long durations did not exist so therefore, a high altitude/near space environment testing capability would have to be developed. After several agency concepts the A3 High Altitude Testing Facility proposal was selected by the J2X engine program on March 2, 2007 and later confirmed by a broad panel of NASA senior leadership in May 2007. This facility is to be built at NASA s John C. Stennis Space Center located near Gulfport, Mississippi. 30 plus years of Space Shuttle Main Engine development and flight certification testing makes Stennis uniquely suited to support the Vision For Space Exploration Return to the Moon. Propellant handling infrastructure, engine assembly facilities, a trained and dedicated workforce and a broad and varied technical support base will all ensure that the A3 facility will be built on time to support the schedule needs of the J2X engine and the ultimate flight

  20. Stepped Hydraulic Geometry in Stepped Channels

    NASA Astrophysics Data System (ADS)

    Comiti, F.; Cadol, D. D.; Wohl, E.

    2007-12-01

    Steep mountain streams typically present a stepped longitudinal profile. Such stepped channels feature tumbling flow, where hydraulic jumps represent an important source of channel roughness (spill resistance). However, the extent to which spill resistance persists up to high flows has not been ascertained yet, such that a faster, skimming flow has been envisaged to begin at those conditions. In order to analyze the relationship between flow resistance and bed morphology, a mobile bed physical model was developed at Colorado State University (Fort Collins, USA). An 8 m-long, 0.6 m-wide flume tilted at a constant 14% slope was used, testing 2 grain-size mixtures differing only for the largest fraction. Experiments were conducted under clear water conditions. Reach-averaged flow velocity was measured using salt tracers, bed morphology and flow depth by a point gage, and surface grain size using commercial image-analysis software. Starting from an initial plane bed, progressively higher flow rates were used to create different bed structures. After each bed morphology was stable with its forming discharge, lower-than-forming flows were run to build a hydraulic geometry curve. Results show that even though equilibrium slopes ranged from 8.5% to 14%, the reach-averaged flow was always sub-critical. Steps formed through a variety of mechanisms, with immobile clasts playing a dominant role by causing local scouring and/or trapping moving smaller particles. Overall, step height, step pool steepness, relative pool area and volume increased with discharge up to the threshold when the bed approached fully- mobilized conditions. For bed morphologies surpassing a minimum profile roughness, a stepped velocity- discharge relationship is evident, with sharp rises in velocity correlated with the disappearance of rollers in pools at flows approaching the formative discharge for each morphology. Flow resistance exhibits an opposite pattern, with drops in resistance being a function

  1. One Step to Learning.

    ERIC Educational Resources Information Center

    Thornton, Carol A.; And Others

    1980-01-01

    Described are activities and games incorporating a technique of "one step" which is used with children with learning difficulties. The purpose of "one step" is twofold, to minimize difficulties with typical trouble spots and to keep the step size of the instruction small. (Author/TG)

  2. A Step Circuit Program.

    ERIC Educational Resources Information Center

    Herman, Susan

    1995-01-01

    Aerobics instructors can use step aerobics to motivate students. One creative method is to add the step to the circuit workout. By incorporating the step, aerobic instructors can accommodate various fitness levels. The article explains necessary equipment and procedures, describing sample stations for cardiorespiratory fitness, muscular strength,…

  3. Regression of altitude-produced cardiac hypertrophy.

    NASA Technical Reports Server (NTRS)

    Sizemore, D. A.; Mcintyre, T. W.; Van Liere, E. J.; Wilson , M. F.

    1973-01-01

    The rate of regression of cardiac hypertrophy with time has been determined in adult male albino rats. The hypertrophy was induced by intermittent exposure to simulated high altitude. The percentage hypertrophy was much greater (46%) in the right ventricle than in the left (16%). The regression could be adequately fitted to a single exponential function with a half-time of 6.73 plus or minus 0.71 days (90% CI). There was no significant difference in the rates of regression for the two ventricles.

  4. High altitude balloon experiments at IIA

    NASA Astrophysics Data System (ADS)

    Nayak, Akshata; Sreejith, A. G.; Safonova, Margarita; Murthy, Jayant

    Recent advances in balloon experiments as well as in electronics have made it possible to fly scientific payloads at costs accessible to university departments. We have begun a program of high altitude ballooning at the Indian Institute of Astrophysics, Bengaluru. The primary purpose of this activity is to test low-cost ultraviolet (UV) payloads for eventual space flight, but we will also try scientific exploration of the phenomena occurring in the upper atmosphere, including sprites and meteorite impacts. We present the results of the initial experiments carried out at the CREST campus of IIA, Hosakote, and describe our plans for the future.

  5. Determining the Altitude of Iridium Flares

    NASA Technical Reports Server (NTRS)

    Foster, James; Owe, Manfred

    1999-01-01

    Iridium flares have nothing to do with the element iridium. Iridium is also the name of a telecommunications company that has been launching satellites into low orbits around the Earth. These satellites are being used for a new type of wireless phone and paging service. Flares have been observed coming from these satellites. These flares have the potential, especially when the full fleet of satellites is in orbit, to disrupt astronomical observations. The paper reviews using simple trigonometry how to calculate the altitude of one of these satellites.

  6. STEP: A Futurevision, Today

    NASA Technical Reports Server (NTRS)

    1994-01-01

    STEP (STandard for the Exchange of Product Model Data) is an innovative software tool that allows the exchange of data between different programming systems to occur and helps speed up the designing in various process industries. This exchange occurs easily between those companies that have STEP, and many industries and government agencies are requiring that their vendors utilize STEP in their computer aided design projects, such as in the areas of mechanical, aeronautical, and electrical engineering. STEP allows the process of concurrent engineering to occur and increases the quality of the design product. One example of the STEP program is the Boeing 777, the first paperless airplane.

  7. High Altitude Ballooning and Site Selection

    NASA Astrophysics Data System (ADS)

    Metcalf, John

    2008-10-01

    High altitude ballooning provides a near-space platform for amateur research projects in science and engineering. This venue allows new experiments, otherwise not conducted from costs or lack of transportation, from WSU and surrounding areas to be flown into the upper atmosphere. A highly skilled and motivated group of scientist and engineering students from WSU have contrived its own high altitude balloon to lift payload capsules filled with experiments and tracking equipment up to 120,000 feet where it then bursts and payload capsules are parachuted into a landing zone. Launch site selection is based upon the safety of those that come within the balloons projected flight path and terrain accessibility from the launch and landing zones. Restricted ground and airspace, mountainous regions, lakes and rivers, and densely populated or high air traffic areas were obstacles to be avoided. Computer flight simulations and region analysis show that there are several viable launch and recovery sites in Utah as well as SE Idaho, SW Wyoming, and NW Colorado.

  8. Optic neuropathy following an altitude exposure.

    PubMed

    Steigleman, Allan; Butler, Frank; Chhoeu, Austin; O'Malley, Timothy; Bower, Eric; Giebner, Stephen

    2003-09-01

    This case report describes a 20-yr-old man who presented with retro-orbital pain and blurred vision in his left eye 3 wk after an altitude exposure in a hypobaric chamber. He was found to have significant deficits in color vision and visual fields consistent with an optic neuropathy in his left eye. The patient was diagnosed with decompression sickness and treated with hyperbaric oxygen with a U.S. Navy Treatment Table VI. All signs and symptoms resolved with a single hyperbaric oxygen treatment but recurred. A head MRI revealed a left frontoethmoid sinus opacity. A concomitant sinusitis was diagnosed. The patient had full resolution of symptoms after a total of four hyperbaric oxygen treatments and antibiotic therapy at 6-wk follow-up. Although a para-infectious etiology for this patient's optic neuropathy cannot be excluded, his history of altitude exposure and significant, rapid response to hyperbaric oxygen treatment strongly implies decompression sickness in this case. PMID:14503679

  9. Conformational and electronic properties of the two cis (5S,6R) and (5R,6S) diastereoisomers of 5,6-dihydroxy-5,6-dihydrothymidine: X-ray and theoretical studies.

    PubMed

    Jolibois, F; Voituriez, L; Grand, A; Cadet, J

    1996-01-01

    The structure of (+)-cis-(5S,6R)-5,6-dihydroxy-5,6-dihydrothymidine was obtained using X-ray crystallography [space group P2(1) with a = 10.130(3) angstroms, b = 6.434(9) angstroms, c = 11.02(5) angstroms, and beta = 112.646(2) angstroms]. The comparison of the two cis diastereoisomers of thymidine glycol (I, II) showed several structural and conformational differences. The solid state structures appear to be in agreement with the results of 1H NMR studies which were carried out in aqueous solution. Conformational and electronic properties of the ground state of the molecules I and II were obtained using ab initio LSD-DFT theory. Only slight differences between the crystal structure and the optimized geometry are observed for each of the two oxidized nucleosides. On the other hand, molecules I and II exhibit significant differences in their electronic properties. In particular, the dipole moment of (5S,6R)-thymidine glycol (I) is twice smaller than that of the (5R,6S) diastereoisomer (II). It is noteworthy that these differences in the electronic properties between the two compounds may be related to changes in the rotameric population around the C4'-C5' bond. The repartition of the electrostatic potential is different in the two compounds. These observations lead to a better understanding of the structural changes when the above lesions are included within a DNA molecule. PMID:8924607

  10. Curcumin Induces Nrf2 Nuclear Translocation and Prevents Glomerular Hypertension, Hyperfiltration, Oxidant Stress, and the Decrease in Antioxidant Enzymes in 5/6 Nephrectomized Rats

    PubMed Central

    Tapia, Edilia; Soto, Virgilia; Ortiz-Vega, Karla Mariana; Zarco-Márquez, Guillermo; Molina-Jijón, Eduardo; Cristóbal-García, Magdalena; Santamaría, José; García-Niño, Wylly Ramsés; Correa, Francisco; Zazueta, Cecilia; Pedraza-Chaverri, José

    2012-01-01

    Renal injury resulting from renal ablation induced by 5/6 nephrectomy (5/6NX) is associated with oxidant stress, glomerular hypertension, hyperfiltration, and impaired Nrf2-Keap1 pathway. The purpose of this work was to know if the bifunctional antioxidant curcumin may induce nuclear translocation of Nrf2 and prevents 5/6NX-induced oxidant stress, renal injury, decrease in antioxidant enzymes, and glomerular hypertension and hyperfiltration. Four groups of rats were studied: (1) control, (2) 5/6NX, (3) 5/6NX +CUR, and (4) CUR (n = 8–10). Curcumin was given by gavage to NX5/6 +CUR and CUR groups (60 mg/kg/day) starting seven days before surgery. Rats were studied 30 days after NX5/6 or sham surgery. Curcumin attenuated 5/6NX-induced proteinuria, systemic and glomerular hypertension, hyperfiltration, glomerular sclerosis, interstitial fibrosis, interstitial inflammation, and increase in plasma creatinine and blood urea nitrogen. This protective effect was associated with enhanced nuclear translocation of Nrf2 and with prevention of 5/6NX-induced oxidant stress and decrease in the activity of antioxidant enzymes. It is concluded that the protective effect of curcumin against 5/6NX-induced glomerular and systemic hypertension, hyperfiltration, renal dysfunction, and renal injury was associated with the nuclear translocation of Nrf2 and the prevention of both oxidant stress and the decrease of antioxidant enzymes. PMID:22919438

  11. Cyclic steps on ice

    NASA Astrophysics Data System (ADS)

    Yokokawa, M.; Izumi, N.; Naito, K.; Parker, G.; Yamada, T.; Greve, R.

    2016-05-01

    Boundary waves often form at the interface between ice and fluid flowing adjacent to it, such as ripples under river ice covers, and steps on the bed of supraglacial meltwater channels. They may also be formed by wind, such as the megadunes on the Antarctic ice sheet. Spiral troughs on the polar ice caps of Mars have been interpreted to be cyclic steps formed by katabatic wind blowing over ice. Cyclic steps are relatives of upstream-migrating antidunes. Cyclic step formation on ice is not only a mechanical but also a thermodynamic process. There have been very few studies on the formation of either cyclic steps or upstream-migrating antidunes on ice. In this study, we performed flume experiments to reproduce cyclic steps on ice by flowing water, and found that trains of steps form when the Froude number is larger than unity. The features of those steps allow them to be identified as ice-bed analogs of cyclic steps in alluvial and bedrock rivers. We performed a linear stability analysis and obtained a physical explanation of the formation of upstream-migrating antidunes, i.e., precursors of cyclic steps. We compared the results of experiments with the predictions of the analysis and found the observed steps fall in the range where the analysis predicts interfacial instability. We also found that short antidune-like undulations formed as a precursor to the appearance of well-defined steps. This fact suggests that such antidune-like undulations correspond to the instability predicted by the analysis and are precursors of cyclic steps.

  12. Tacrolimus restores podocyte injury and stabilizes the expression of Cabin1 in 5/6 nephrectomized rats.

    PubMed

    Wen, Yueqiang; Liu, Lingling; Zhou, Peilan; Li, Huiyuan; Wang, Zebin; Zhang, Yajie; Liang, Jianbo

    2016-05-01

    Podocyte injury is a vital factor, which induces massive proteinuria. Studies have shown that tacrolimus (TAC) protected podocyte via stabilizing cytoskeleton. Our latest study indicates that calcineurin binding protein 1 (Cabin1) undergoes nuclear translocation during podocytes injury. Whether TAC targets on Cabin1 during podocyte injury is still not clear. This study establishes non-immunological proteinuric model. To observe the effect of the treatment of TAC on Cabin1 expression in 5/6 nephrectomized rats. Sprague-Dawley rats were injected with TAC (0.2 mg/kg/day) for 4-8 weeks after 5/6 nephrectomy. Then, rats were sacrificed in the eighth week after operation, renal tissues were processed for morphological studies under light and electrical microscope. Cabin1 expression and distribution were detected by western blot and indirect immunofluorescence staining. In 5/6 nephrectomized rats, urinary protein excretion reached 90.2 ± 30.1 mg/24 h, glomerular sclerosis index and tubulointerstitial fibrosis score were significantly increased, and widespread of podocyte foot processes fusion was found. Moreover, Cabin1 protein expression was markedly increased, and its distribution became much more obviously in podocytes nuclei. In TAC treated rats, urinary protein excretion significantly decreased (44.9 ± 22.5 mg/24 h), glomerular sclerosis and tubulointerstitial fibrosis were alleviated, and podocyte foot processes fusion was inhibited. Furthermore, TAC alleviated the increased protein expression and abnormal distribution of Cabin1. In conclusion, TAC restores podocyte injury and stabilizes the expression of Cabin1. Cabin1 may become a new target to demonstrate the mechanism of TAC in podocyte injury. PMID:26905810

  13. Phagraphene: A Low-Energy Graphene Allotrope Composed of 5-6-7 Carbon Rings with Distorted Dirac Cones.

    PubMed

    Wang, Zhenhai; Zhou, Xiang-Feng; Zhang, Xiaoming; Zhu, Qiang; Dong, Huafeng; Zhao, Mingwen; Oganov, Artem R

    2015-09-01

    Using systematic evolutionary structure searching we propose a new carbon allotrope, phagraphene [fæ'græfi:n], standing for penta-hexa-hepta-graphene, because the structure is composed of 5-6-7 carbon rings. This two-dimensional (2D) carbon structure is lower in energy than most of the predicted 2D carbon allotropes due to its sp(2)-binding features and density of atomic packing comparable to graphene. More interestingly, the electronic structure of phagraphene has distorted Dirac cones. The direction-dependent cones are further proved to be robust against external strain with tunable Fermi velocities. PMID:26262429

  14. Comparison of energy calibration of Prognoz 5, 6, 7, and 8 and other hard-X-ray solar photometers

    NASA Astrophysics Data System (ADS)

    Farnik, F.; Valnicek, B.; Sylwester, B.; Sylwester, J.; Jakimiec, J.

    1984-08-01

    The data obtained by the Prognoz 5, 6, 7, and 8 hard-X-ray photometers are compared with the measurements carried out by similar instruments aboard Solrad 11, ISEE 3, SMM, and Hinotori satellites. Using the method of relative-amplitude analysis, the apparent disagreement in the energy-discrimination-level calibration between the instruments is pointed out. The results of the comparison and possible sources of disagreement are given. An international effort to develop a system of uniform prelaunch calibration of photometers based on a reference calibration source is suggested.

  15. Synthesis of Substituted 2,3,5,6-tetraarylbenzo(1,2-b:5,4-b')difurans

    NASA Technical Reports Server (NTRS)

    Abdul-Aziz, Mahmoud; Auping, Judith V.; Meador, Michael A.

    1995-01-01

    A series of substituted 2,3,5,6-tetraarylbenzo(l,2-b:5,4-b')difurans 1 was synthesized. This synthesis is based upon the photocyclization of 2,5-dibenzoylresorcinol dibenzyl ethers to the corresponding tetrahydrobenzo(1,2-b:5,4-b')difurans. Treatment of the photoproducts with methanesulfonyl chloride in pyridine afforded 1 in overall yields ranging from 30-72%. A number of these compounds have high fluorescence quantum yields (of phi(sub f) = 0.76-0.90), and their fluorescence spectra exhibit large solvatochromic shifts. These compounds may be suitable for use as fluorescent probes.

  16. Bronchial asthma: advice for patients traveling to high altitude.

    PubMed

    Cogo, Annalisa; Fiorenzano, Giuseppe

    2009-01-01

    This article examines the possibility of traveling to altitude for patients suffering from bronchial asthma. The mountain environment, the adaptations of the respiratory system to high altitude, the underlying patho-physiologies of asthma, and the recommendations for patients, according to altitude, are discussed. In summary, staying at low altitude has a significant beneficial effect for asthmatic patients, due to the reduction of airway inflammation and the lower response to bronchoconstrictor stimuli; for staying at moderate altitude, there is conflicting information and no clinical data; at high altitude, the environment seems beneficial for well-controlled asthmatics, but intense exercise and upper airway infections (frequent during trekking) can be additional risks and should be avoided. Further, in remote areas health facilities are often difficult to reach. PMID:19519226

  17. The self-assembly of 5,6,7-trithiapentacene-13-one molecules on gold: from low-coverage molecular chains to monolayer coverage

    NASA Astrophysics Data System (ADS)

    Larson, Amanda; Tang, Jian-Ming; Pohl, Karsten

    2015-03-01

    Understanding electronic devices down to the atomic scale is essential for the development of novel organic molecule based nanotechnologies. 5,6,7-trithiapentacene-13-one (TTPO) is a promising organic semiconductor with potential applications in high temperature photovoltaic devices. Scanning tunneling microscopy (STM) of TTPO on the close-packed stepped Au (788) surface reveals interesting nanoscale surface structures ranging from molecular chains at low coverage to an ordered self-assembled monolayer. Density functional theory (DFT) calculations have been used to further probe this unique 3-D angular assembly, where the long-axis of TTPO is parallel to the gold surface, distinctive from previously observed pentacene and pentacene derivative assemblies on surfaces. It is the lateral arrangement of the underlying pentacene backbone of the molecule that is unique, causing the thiol substituent side of the molecule to be angled down towards the gold surface, with the oxygen angled away. Combining imaging with density functional theory calculations allows for classification of these self-assembled structures with particular interest being directed toward the interaction between TTPO and gold at this organic-metallic interface. Understanding of the structure of such interfaces can potentially guide nanoscale modifications for improved electrical transport and energy-conversion efficiency in future devices.

  18. A DFT study of the [3 + 2] versus [4 + 2] cycloaddition reactions of 1,5,6-trimethylpyrazinium-3-olate with methyl methacrylate.

    PubMed

    Domingo, Luis R; Sáez, Jose A; Joule, John A; Rhyman, Lydia; Ramasami, Ponnadurai

    2013-02-15

    The reaction between 1,5,6-trimethylpyrazinium-3-olate and methyl methacrylate (MMA) yielding a lactone-lactam has been studied using the DFT method at the B3LYP/6-31G(d) level. It is concluded that formation of the lactone-lactam is a domino process involving three consecutive reactions: (i) a 1,3-dipolar cycloaddition (13DC) reaction between the pyrazinium-3-olate and MMA yielding a [3 + 2] cycloadduct (CA); (ii) a skeletal rearrangement, which converts the [3 + 2] CA into a formal [4 + 2] CA, possessing a diazabicyclo[2.2.2]octane structure; and finally, (iii) an S(N)2 reaction, promoted by halide anion, with concomitant nucleophilic attack of the created carboxylate anion on an iminium carbon with formation of the lactone ring present in the lactone-lactam. Analysis of the four competitive channels associated with the 13DC reaction indicates that this cycloaddition takes place with complete endo stereoselectivity and 6 regioselectivity, yielding [3 + 2] CA. The subsequent skeletal rearrangement also takes place in an elementary step via a non-concerted mechanism. Electron localization function bonding analysis makes it possible to establish that the bicyclo[2.2.2]octane skeleton present in the lactone-lactam complex structure is not attained via a Diels-Alder reaction between pyrazinium-3-olate and MMA. PMID:23342990

  19. Control of erythropoiesis after high altitude acclimatization.

    PubMed

    Savourey, Gustave; Launay, Jean-Claude; Besnard, Yves; Guinet, Angélique; Bourrilhon, Cyprien; Cabane, Damien; Martin, Serge; Caravel, Jean-Pierre; Péquignot, Jean-Marc; Cottet-Emard, Jean-Marie

    2004-10-01

    Erythropoiesis was studied in 11 subjects submitted to a 4-h hypoxia (HH) in a hypobaric chamber (4,500 m, barometric pressure 58.9 kPa) both before and after a 3-week sojourn in the Andes. On return to sea level, increased red blood cells (+3.27%), packed cell volume (+4.76%), haemoglobin (+6.55%) ( P<0.05), and increased arterial partial pressure of oxygen (+8.56%), arterial oxygen saturation (+7.40%) and arterial oxygen blood content ( C(a)O(2)) (+12.93%) at the end of HH ( P<0.05) attested high altitude acclimatization. Reticulocytes increased during HH after the sojourn only (+36.8% vs +17.9%, P<0.01) indicating a probable higher reticulocyte release and/or production despite decreased serum erythropoietin (EPO) concentrations (-46%, P<0.01). Hormones (thyroid, catecholamines and cortisol), iron status (serum iron, ferritin, transferrin and haptoglobin) and renal function (creatinine, renal, osmolar and free-water clearances) did not significantly vary (except for lower thyroid stimulating hormone at sea level, P<0.01). Levels of 2,3-diphosphoglycerate (2,3-DPG) increased throughout HH on return (+14.7%, P<0.05) and an inverse linear relationship was found between 2,3-DPG and EPO at the end of HH after the sojourn only ( r=-0.66, P<0.03). Inverse linear relationships were also found between C(a)O(2) and EPO at the end of HH before ( r=-0.63, P<0.05) and after the sojourn ( r=-0.60, P=0.05) with identical slopes but different ordinates at the origin, suggesting that the sensitivity but not the gain of the EPO response to hypoxia was modified by altitude acclimatization. Higher 2,3-DPG levels could partly explain this decreased sensitivity of the EPO response to hypoxia. In conclusion, we show that altitude acclimatization modifies the control of erythropoiesis not only at sea level, but also during a subsequent hypoxia. PMID:15248067

  20. Work at high altitude and oxidative stress: antioxidant nutrients.

    PubMed

    Askew, E W

    2002-11-15

    A significant portion of the world's geography lies above 10,000 feet elevation, an arbitrary designation that separates moderate and high altitude. Although the number of indigenous people living at these elevations is relatively small, many people travel to high altitude for work or recreation, exposing themselves to chronic or intermittent hypoxia and the associated risk of acute mountain sickness (AMS) and less frequently, high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE). The symptoms of AMS (headache, nausea, anorexia, fatigue, lassitude) occur in those who travel too high, too fast. Some investigators have linked the development of these symptoms with the condition of altered blood-brain barrier permeability, possibly related to hypoxia induced free radical formation. The burden of oxidative stress increases during the time spent at altitude and may even persist for some time upon return to sea level. The physiological and medical consequences of increased oxidative stress engendered by altitude is unclear; indeed, hypoxia is believed to be the trigger for the cascade of signaling events that ultimately leads to adaptation to altitude. These signaling events include the generation of reactive oxygen species (ROS) that may elicit important adaptive responses. If produced in excess, however, these ROS may contribute to impaired muscle function and reduced capillary perfusion at altitude or may even play a role in precipitating more serious neurological and pulmonary crisis. Oxidative stress can be observed at altitude without strenuous physical exertion; however, environmental factors other than hypoxia, such as exercise, UV light exposure and cold exposure, can also contribute to the burden. Providing antioxidant nutrients via the diet or supplements to the diet can reduce oxidative stress secondary to altitude exposure. In summary, the significant unanswered question concerning altitude exposure and antioxidant supplementation is

  1. High-altitude pulmonary edema: diagnosis, prevention, and treatment.

    PubMed

    Pennardt, Andre

    2013-01-01

    High-altitude pulmonary edema (HAPE) is a lethal, noncardiogenic form of pulmonary edema that afflicts susceptible individuals after rapid ascent to high altitude above 2,500 m. Prevention of HAPE is achieved most effectively by gradual ascent allowing time for proper acclimatization. Certain prophylactic medications may further reduce the risk of ascending to high altitude in individuals with a prior history of HAPE. The most effective and reliable treatment of HAPE is immediate descent and administration of supplemental oxygen. PMID:23478563

  2. Golgi-Cox Staining Step by Step

    PubMed Central

    Zaqout, Sami; Kaindl, Angela M.

    2016-01-01

    Golgi staining remains a key method to study neuronal morphology in vivo. Since most protocols delineating modifications of the original staining method lack details on critical steps, establishing this method in a laboratory can be time-consuming and frustrating. Here, we describe the Golgi-Cox staining in such detail that should turn the staining into an easily feasible method for all scientists working in the neuroscience field. PMID:27065817

  3. OPTIMUM PLASMA STATES FOR NEXT STEP TOKAMAKS

    SciTech Connect

    LIN-LIU,YR; STAMBAUGH,RD

    2002-11-01

    OAK A271 OPTIMUM PLASMA STATES FOR NEXT STEP TOKAMAKS. The dependence of the ideal ballooning {beta} limit on aspect ratio, A, and elongation {kappa} is systematically explored for nearly 100% bootstrap current driven tokamak equilibria in a wide range of the shape parameters (A = 1.2-7.0, {kappa} = 1.5-6.0 with triangularity {delta} = 0.5). The critical {beta}{sub N} is shown to be optimal at {kappa} = 3.0-4.0 for all A studied and increases as A decreases with a dependence close to A{sup -0.5}. The results obtained can be used as a theoretical basis for the choice of optimum aspect ratio and elongation of next step burning plasma tokamaks or tokamak reactors.

  4. Estimation of doses to Taikonauts in SZ-5/6/7 missions using a male voxel model

    NASA Astrophysics Data System (ADS)

    Xu, Feng; Zeng, Zhi; Jia, Xianghong

    2011-11-01

    Objective To assess the Taikonaut's space radiation risk organ, doses have been calculated using a male voxel model. Methods A male voxel model based on MRI was built. The proton spectra were calculated by AP-8 with SPENVIS and Badhwar's GCR model. The general 3 D Monte Carlo particle and heavy ion transport code GEANT4 was used to calculate the average doses for some organs and tissues. Results After 1 g/cm2 shielding shell, the absorbed dose rate of skin is 0.6 mGy/d and effective dose rate is estimated to be 2.3 mSv/d during the SZ-5/6/7 mission. The total effective dosesof the taikonauts are estimated to be around 2.0 mSv during the SZ-5 mission, 10.9mSv during the SZ-6 mission and 6.5 mSv during the SZ-7 mission separately. Conclusion The calculated skin doses are closed to the values measured by TLDs in SZ-5/6/7, and within the range of 0.2~0.6mSv published by USA and Russia.

  5. Estimation of doses to Taikonauts in SZ-5/6/7 missions using a male voxel model

    NASA Astrophysics Data System (ADS)

    Xu, Feng; Zeng, Zhi; Jia, Xianghong

    2012-03-01

    Objective To assess the Taikonaut's space radiation risk organ, doses have been calculated using a male voxel model. Methods A male voxel model based on MRI was built. The proton spectra were calculated by AP-8 with SPENVIS and Badhwar's GCR model. The general 3 D Monte Carlo particle and heavy ion transport code GEANT4 was used to calculate the average doses for some organs and tissues. Results After 1 g/cm2 shielding shell, the absorbed dose rate of skin is 0.6 mGy/d and effective dose rate is estimated to be 2.3 mSv/d during the SZ-5/6/7 mission. The total effective dosesof the taikonauts are estimated to be around 2.0 mSv during the SZ-5 mission, 10.9mSv during the SZ-6 mission and 6.5 mSv during the SZ-7 mission separately. Conclusion The calculated skin doses are closed to the values measured by TLDs in SZ-5/6/7, and within the range of 0.2~0.6mSv published by USA and Russia.

  6. Polarization components in π0 photoproduction at photon energies up to 5.6 GeV

    SciTech Connect

    Luo, W.; Brash, E. J.; Gilman, R.; Jones, M. K.; Meziane, M.; Pentchev, L.; Perdrisat, C. F; Puckett, A. J.R.; Punjabi, V.; Wesselmann, F. R.; Marsh, A.; Matulenko, Y.; Maxwell, J.; Meekins, D.; Melnik, Y.; Miller, J.; Mkrtchyan, A.; Mkrtchyan, H.; Moffit, B.; Moreno, O.; Mulholland, J.; Narayan, A.; Nuruzzaman, .; Nedev, S.; Piasetzky, E.; Pierce, W.; Piskunov, N. M.; Prok, Y.; Ransome, R. D.; Razin, D. S.; Reimer, P. E.; Reinhold, J.; Rondon, O.; Shabestari, M.; Shahinyan, A.; Shestermanov, K.; Sirca, S.; Sitnik, I.; Smykov, L.; Smith, G.; Solovyev, L.; Solvignon, P.; Strakovsky, I. I; Subedi, R.; Suleiman, R.; Tomasi-Gustafsson, E.; Vasiliev, A.; Veilleux, M.; Wood, S.; Ye, Z.; Zanevsky, Y.; Zhang, X.; Zhang, Y.; Zheng, X.; Zhu, L.; Ahmidouch, A.; Albayrak, I.; Aniol, K. A.; Arrington, J.; Asaturyan, A.; Ates, O.; Baghdasaryan, H.; Benmokhtar, F.; Bertozzi, W.; Bimbot, L.; Bosted, P.; Boeglin, W.; Butuceanu, C.; Carter, P.; Chernenko, S.; Christy, M. E.; Commisso, M.; Cornejo, J. C.; Covrig, S.; Danagoulian, S.; Daniel, A.; Davidenko, A.; Day, D.; Dhamija, S.; Dutta, D.; Ent, R.; Frullani, S.; Fenker, H.; Frlez, E.; Garibaldi, F.; Gaskell, D.; Gilad, S.; Goncharenko, Y.; Hafidi, K.; Hamilton, D.; Higinbotham, D. W.; Hinton, W.; Horn, T.; Hu, B.; Huang, J.; Huber, G. M.; Jensen, E.; Kang, H.; Keppel, C.; Khandaker, M.; King, P.; Kirillov, D.; Kohl, M.; Kravtsov, V.; Kumbartzki, G.; Li, Y.; Mamyan, V.; Margaziotis, D. J.; Markowitz, P.

    2012-05-31

    We present new data for the polarization observables of the final state proton in the 1H(→ γ, → p)π0 reaction. These data can be used to test predictions based on hadron helicity conservation (HHC) and perturbative QCD (pQCD). These data have both small statistical and systematic uncertainties, and were obtained with beam energies between 1.8 and 5.6 GeV and for π0 scattering angles larger than 75{sup o} in center-of-mass (c.m.) frame. The data extend the polarization measurements data base for neutral pion photoproduction up to Eγ = 5.6 GeV. The results show non-zero induced polarization above the resonance region. The polarization transfer components vary rapidly with the photon energy and π0 scattering angle in the center-of-mass frame. This indicates that HHC does not hold and that the pQCD limit is still not reached in the energy regime of this experiment.

  7. Polarization components in π0 photoproduction at photon energies up to 5.6 GeV

    DOE PAGESBeta

    Luo, W.; Brash, E. J.; Gilman, R.; Jones, M. K.; Meziane, M.; Pentchev, L.; Perdrisat, C. F; Puckett, A. J.R.; Punjabi, V.; Wesselmann, F. R.; et al

    2012-05-31

    We present new data for the polarization observables of the final state proton in the 1H(→ γ, → p)π0 reaction. These data can be used to test predictions based on hadron helicity conservation (HHC) and perturbative QCD (pQCD). These data have both small statistical and systematic uncertainties, and were obtained with beam energies between 1.8 and 5.6 GeV and for π0 scattering angles larger than 75{sup o} in center-of-mass (c.m.) frame. The data extend the polarization measurements data base for neutral pion photoproduction up to Eγ = 5.6 GeV. The results show non-zero induced polarization above the resonance region. Themore » polarization transfer components vary rapidly with the photon energy and π0 scattering angle in the center-of-mass frame. This indicates that HHC does not hold and that the pQCD limit is still not reached in the energy regime of this experiment.« less

  8. Smc5/6 Mediated Sumoylation of the Sgs1-Top3-Rmi1 Complex Promotes Removal of Recombination Intermediates.

    PubMed

    Bonner, Jaclyn N; Choi, Koyi; Xue, Xiaoyu; Torres, Nikko P; Szakal, Barnabas; Wei, Lei; Wan, Bingbing; Arter, Meret; Matos, Joao; Sung, Patrick; Brown, Grant W; Branzei, Dana; Zhao, Xiaolan

    2016-07-12

    Timely removal of DNA recombination intermediates is critical for genome stability. The DNA helicase-topoisomerase complex, Sgs1-Top3-Rmi1 (STR), is the major pathway for processing these intermediates to generate conservative products. However, the mechanisms that promote STR-mediated functions remain to be defined. Here we show that Sgs1 binds to poly-SUMO chains and associates with the Smc5/6 SUMO E3 complex in yeast. Moreover, these interactions contribute to the sumoylation of Sgs1, Top3, and Rmi1 upon the generation of recombination structures. We show that reduced STR sumoylation leads to accumulation of recombination structures, and impaired growth in conditions when these structures arise frequently, highlighting the importance of STR sumoylation. Mechanistically, sumoylation promotes STR inter-subunit interactions and accumulation at DNA repair centers. These findings expand the roles of sumoylation and Smc5/6 in genome maintenance by demonstrating that they foster STR functions in the removal of recombination intermediates. PMID:27373152

  9. 5,6-Dehydrokawain from Alpinia zerumbet promotes osteoblastic MC3T3-E1 cell differentiation.

    PubMed

    Kumagai, Momochika; Mishima, Takashi; Watanabe, Akio; Harada, Teppei; Yoshida, Izumi; Fujita, Kazuhiro; Watai, Masatoshi; Tawata, Shinkichi; Nishikawa, Keisuke; Morimoto, Yoshiki

    2016-07-01

    Bone homeostasis is maintained by balancing bone formation and bone resorption, but an imbalance between them is associated with various bone-related diseases such as osteoporosis and rheumatoid arthritis. We found that 5,6-dehydrokawain (DK) and dihydro-5,6-dehydrokawain (DDK), which were isolated as promising compounds from Alpinia zerumbet rhizomes, promote differentiation of osteoblastic MC3T3-E1 cells. DK and DDK increased the alkaline phosphatase activity and matrix mineralization of MC3T3-E1 cells. DK exerts larger effects than DDK. The gene expression of runt-related transcription factor 2 and osterix, which are essential transcription factors in the early period of osteoblast differentiation, was significantly increased by DK treatment. The mRNA level of distal-less homeobox 5 was also enhanced by DK treatment, and DK activated the p38 mitogen-activated protein kinase pathway. Therefore, DK may have clinical potential for preventing osteoporosis, and could be considered as a potential anabolic therapeutic agent. PMID:26940726

  10. Polarization components in π0 photoproduction at photon energies up to 5.6 GeV.

    PubMed

    Luo, W; Brash, E J; Gilman, R; Jones, M K; Meziane, M; Pentchev, L; Perdrisat, C F; Puckett, A J R; Punjabi, V; Wesselmann, F R; Ahmidouch, A; Albayrak, I; Aniol, K A; Arrington, J; Asaturyan, A; Ates, O; Baghdasaryan, H; Benmokhtar, F; Bertozzi, W; Bimbot, L; Bosted, P; Boeglin, W; Butuceanu, C; Carter, P; Chernenko, S; Christy, M E; Commisso, M; Cornejo, J C; Covrig, S; Danagoulian, S; Daniel, A; Davidenko, A; Day, D; Dhamija, S; Dutta, D; Ent, R; Frullani, S; Fenker, H; Frlez, E; Garibaldi, F; Gaskell, D; Gilad, S; Goncharenko, Y; Hafidi, K; Hamilton, D; Higinbotham, D W; Hinton, W; Horn, T; Hu, B; Huang, J; Huber, G M; Jensen, E; Kang, H; Keppel, C; Khandaker, M; King, P; Kirillov, D; Kohl, M; Kravtsov, V; Kumbartzki, G; Li, Y; Mamyan, V; Margaziotis, D J; Markowitz, P; Marsh, A; Matulenko, Y; Maxwell, J; Mbianda, G; Meekins, D; Melnik, Y; Miller, J; Mkrtchyan, A; Mkrtchyan, H; Moffit, B; Moreno, O; Mulholland, J; Narayan, A; Nuruzzaman; Nedev, S; Piasetzky, E; Pierce, W; Piskunov, N M; Prok, Y; Ransome, R D; Razin, D S; Reimer, P E; Reinhold, J; Rondon, O; Shabestari, M; Shahinyan, A; Shestermanov, K; Širca, S; Sitnik, I; Smykov, L; Smith, G; Solovyev, L; Solvignon, P; Strakovsky, I I; Subedi, R; Suleiman, R; Tomasi-Gustafsson, E; Vasiliev, A; Veilleux, M; Wood, S; Ye, Z; Zanevsky, Y; Zhang, X; Zhang, Y; Zheng, X; Zhu, L

    2012-06-01

    We present new data for the polarization observables of the final state proton in the (1)H(γ,p)π(0) reaction. These data can be used to test predictions based on hadron helicity conservation and perturbative QCD. These data have both small statistical and systematic uncertainties and were obtained with beam energies between 1.8 and 5.6 GeV and for π(0) scattering angles larger than 75° in the center-of-mass frame. The data extend the polarization measurements database for neutral pion photoproduction up to E(γ)=5.6 GeV. The results show a nonzero induced polarization above the resonance region. The polarization transfer components vary rapidly with the photon energy and π(0) scattering angle in the center-of-mass frame. This indicates that hadron helicity conservation does not hold and that the perturbative QCD limit is still not reached in the energy regime of this experiment. PMID:23180491

  11. Renal endothelial function is associated with the anti-proteinuric effect of ACE inhibition in 5/6 nephrectomized rats.

    PubMed

    Vettoretti, Simone; Vavrinec, Peter; Ochodnicky, Peter; Deelman, Leo E; De Zeeuw, Dick; Henning, Rob H; Buikema, Hendrik

    2016-05-01

    In healthy rats, the physiological variation of baseline endothelial function of intrarenal arteries correlates with the severity of renal damage in response to a subsequent specific renal injury. However, whether such a variation in endothelial function may also condition or predict the variable response to angiotensin-converting enzyme-inhibiting treatment in these individuals has not been addressed before. To study this, 5/6 nephrectomy was performed to induce renal injury and chronic kidney disease in a group of healthy Wistar rats. At the time of nephrectomy, interlobar arteries were obtained from the extirpated right kidney and studied in vitro for endothelium-dependent relaxation to acetylcholine. Six weeks thereafter, treatment with lisinopril was started (n = 11) and continued for 9 wk. Proteinuria (metabolic cages) and systolic blood pressure (SBP; tail cuff) were evaluated weekly, and these were analyzed in relation to renal endothelial function at baseline. 5/6 Nephrectomy induced an increase in SBP and progressive proteinuria. Treatment with lisinopril reduced SBP and slowed proteinuria, albeit to a variable degree among individuals. The acetylcholine-induced renal artery dilation at baseline negatively correlated with lisinopril-induced reduction of proteinuria (r(2) = 0.648, P = 0.003) and with the decrease in SBP (r(2) = 0.592, P = 0.006). Our data suggest that angiotensin-converting enzyme-inhibitor attenuates the progression of renal damage the most in those individuals with decreased basal renal endothelial-mediated vasodilation. PMID:26911850

  12. Evaluation of a color-coded Landsat 5/6 ratio image for mapping lithologic differences in western South Dakota

    USGS Publications Warehouse

    Raines, Gary L.; Bretz, R.F.; Shurr, George W.

    1979-01-01

    From analysis of a color-coded Landsat 5/6 ratio, image, a map of the vegetation density distribution has been produced by Raines of 25,000 sq km of western South Dakota. This 5/6 ratio image is produced digitally calculating the ratios of the bands 5 and 6 of the Landsat data and then color coding these ratios in an image. Bretz and Shurr compared this vegetation density map with published and unpublished data primarily of the U.S. Geological Survey and the South Dakota Geological Survey; good correspondence is seen between this map and existing geologic maps, especially with the soils map. We believe that this Landsat ratio image can be used as a tool to refine existing maps of surficial geology and bedrock, where bedrock is exposed, and to improve mapping accuracy in areas of poor exposure common in South Dakota. In addition, this type of image could be a useful, additional tool in mapping areas that are unmapped.

  13. Does 'altitude training' increase exercise performance in elite athletes?

    PubMed

    Lundby, Carsten; Robach, Paul

    2016-07-01

    What is the topic of this review? The aim is to evaluate the effectiveness of various altitude training strategies as investigated within the last few years. What advances does it highlight? Based on the available literature, the foundation to recommend altitude training to athletes is weak. Athletes may use one of the various altitude training strategies to improve exercise performance. The scientific support for such strategies is, however, not as sound as one would perhaps imagine. The question addressed in this review is whether altitude training should be recommended to elite athletes or not. PMID:27173805

  14. APOLLO 16 COMMANDER JOHN YOUNG ENTERS ALTITUDE CHAMBER FOR TESTS

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Apollo 16 commander John W. Young prepares to enter the lunar module in an altitude chamber in the Manned Spacecraft Operations Building at the spaceport prior to an altitude run. During the altitude run, in which Apollo 16 lunar module pilot Charles M. Duke also participated, the chamber was pumped down to simulate pressure at an altitude in excess of 200,000 feet. Young, Duke and command module pilot Thomas K. Mattingly II, are training at the Kennedy Space Center for the Apollo 16 mission. Launch is scheduled from Pad 39A, March 17, 1972.

  15. A study of altitude-constrained supersonic cruise transport concepts

    NASA Technical Reports Server (NTRS)

    Tice, David C.; Martin, Glenn L.

    1992-01-01

    The effect of restricting maximum cruise altitude on the mission performance of two supersonic transport concepts across a selection of cruise Mach numbers is studied. Results indicate that a trapezoidal wing concept can be competitive with an arrow wing depending on the altitude and Mach number constraints imposed. The higher wing loading of trapezoidal wing configurations gives them an appreciably lower average cruise altitude than the lower wing loading of the arrow wing configurations, and this advantage increases as the maximum allowable cruise altitude is reduced.

  16. Variability of cloudiness at airline cruise altitudes from GASP measurements

    NASA Technical Reports Server (NTRS)

    Jasperson, W. H.; Nastrom, G. D.; Davis, R. E.; Holdeman, J. D.

    1985-01-01

    Additional statistics relating to the climatology of cloud cover at airline cruise altitudes are presented. The data were obtained between 1975 and 1979 from commercial airliners participating in the Global Atmospheric Sampling Program (GASP). The statistics describe the seasonal, latitudinal and altitudinal variation in cloudiness parameters as well as differences in the high-altitude cloud structure attributed to cyclone and convective-cloud generation processes. The latitudinal distribution of cloud cover derived form the GASP data was found to agree with high-altitude satellite observations. The relationships between three different measures of cloudiness and the relative vorticity at high altitudes is also discussed.

  17. The pulmonary circulation of some domestic animals at high altitude

    NASA Astrophysics Data System (ADS)

    Anand, I.; Heath, D.; Williams, D.; Deen, M.; Ferrari, R.; Bergel, D.; Harris, P.

    1988-03-01

    Pulmonary haemodynamics and the histology of the pulmonary vasculature have been studied at high altitude in the yak, in interbreeds between yaks and cattle, and in domestic goats and sheep indigenous to high altitudes together with crosses between them and low-altitude strains. Cattle at high altitude had a higher pulmonary arterial pressure than cattle at low altitude. The yak and two interbreeds with cattle (dzos and stols) had a low pulmonary arterial pressure compared with cattle, while the medial thickness of the small pulmonary arteries was less than would be expected in cattle, suggesting that the yak has a low capacity for hypoxic pulmonary vasoconstriction and that this characteristic is transmitted genetically. Goats and sheep showed haemodynamic evidence of a limited response of the pulmonary circulation to high altitude, but no evidence that the high altitude breeds had lost this response. There were no measurable differences in the thickness of the media of the small pulmonary arteries between high- and low-altitude breeds of goats and sheep. All these species showed prominent intimal protrusions of muscle into the pulmonary veins but no specific effect of high altitude in this respect.

  18. Pulmonary hemodynamics in children living at high altitudes.

    PubMed

    Penaloza, Dante; Sime, Francisco; Ruiz, Luis

    2008-01-01

    There are numerous publications on altitude-related diseases in adults. In addition, an International Consensus Statement published in 2001 deals with altitude-related illnesses occurring in lowland children who travel to high altitudes. However, despite the millions of children living permanently at high altitudes around the world, there are few publications on altitude-related diseases and pulmonary hemodynamics in this pediatric population. In this paper, we review the published literature on this subject. First, the pulmonary hemodynamics of healthy children (newborns, infants, children, and adolescents) residing at altitudes above 4000 m are summarized. Asymptomatic pulmonary hypertension, which slowly declines with increasing age, is found in these children. This is followed by a discussion of the functional closure of ductus arteriosus, which is delayed at high altitude. Then, the high prevalence of patent ductus arteriosus (PDA) in highland children and the pulmonary hemodynamics in these patients are described. Next, the pulmonary hemodynamics in highland children who suffer high altitude pulmonary edema (HAPE) after a short stay at lower levels is discussed, and the possible reasons for susceptibility to reentry HAPE in this pediatric population are postulated. The pulmonary hemodynamics in children with subacute mountain sickness (SMS) are then described. Moderate to severe pulmonary hypertension is a common finding in all these altitude-related diseases. Finally, the management of these clinical conditions is outlined. PMID:18800956

  19. Power Budget Analysis for High Altitude Airships

    NASA Technical Reports Server (NTRS)

    Choi, Sang H.; Elliott, James R.; King, Glen C.

    2006-01-01

    The High Altitude Airship (HAA) has various potential applications and mission scenarios that require onboard energy harvesting and power distribution systems. The energy source considered for the HAA s power budget is solar photon energy that allows the use of either photovoltaic (PV) cells or advanced thermoelectric (ATE) converters. Both PV cells and an ATE system utilizing high performance thermoelectric materials were briefly compared to identify the advantages of ATE for HAA applications in this study. The ATE can generate a higher quantity of harvested energy than PV cells by utilizing the cascaded efficiency of a three-staged ATE in a tandem mode configuration. Assuming that each stage of ATE material has the figure of merit of 5, the cascaded efficiency of a three-staged ATE system approaches the overall conversion efficiency greater than 60%. Based on this estimated efficiency, the configuration of a HAA and the power utility modules are defined.

  20. Threshold altitude resulting in decompression sickness

    NASA Technical Reports Server (NTRS)

    Kumar, K. V.; Waligora, James M.; Calkins, Dick S.

    1990-01-01

    A review of case reports, hypobaric chamber training data, and experimental evidence indicated that the threshold for incidence of altitude decompression sickness (DCS) was influenced by various factors such as prior denitrogenation, exercise or rest, and period of exposure, in addition to individual susceptibility. Fitting these data with appropriate statistical models makes it possible to examine the influence of various factors on the threshold for DCS. This approach was illustrated by logistic regression analysis on the incidence of DCS below 9144 m. Estimations using these regressions showed that, under a noprebreathe, 6-h exposure, simulated EVA profile, the threshold for symptoms occurred at approximately 3353 m; while under a noprebreathe, 2-h exposure profile with knee-bends exercise, the threshold occurred at 7925 m.

  1. Temporal, latitude and altitude absorbed dose dependences

    NASA Astrophysics Data System (ADS)

    Stozhkov, Y.; Svirzhevsky, N.; Bazilevskaya, G.

    The regular balloon measurements in the Earth's atmosphere are carried on at the Lebedev Physical Institute since 1957. The regular balloon flights have been made at the high latitude stations (near Murmansk - northern hemisphere and Mi ny -r Antarctica) and at the middle latitude (Moscow). Based on these long-term measurements as well as on the latitude data obtained in the several Soviet Antarctic expeditions the calculations of absorbed doses were fulfilled for altitudes of 10, 15, 20 and 30 km. The absorbed dose dependences on the geomagnetic cutoff rigidities and the phase of the 11-year solar cycle were found. The evaluation of the solar proton events and energetic electron precipitation contributions to the absorbed dose enhancements was made.

  2. Anticoagulation Considerations for Travel to High Altitude.

    PubMed

    DeLoughery, Thomas G

    2015-09-01

    DeLoughery, Thomas G. Anticoagulation considerations for travel to high altitude. High Alt Med Biol 16:181-185, 2015.-An increasing percentage of the population are on anticoagulation medicine for clinical reasons ranging from stroke prevention in atrial fibrillation to long term prevention of deep venous thrombosis. In recent years, several new direct oral anticoagulants have entered the market. The key questions that should be kept in mind when approaching a potential traveler on anticoagulation are: 1) why is the patient on anticoagulation? 2) do they need to stay on anticoagulation? 3) what are the choices for their anticoagulation? 4) will there be any drug interactions with medications needed for travel? and 5) how will they monitor their anticoagulation while traveling? Knowing the answers to these questions then can allow for proper counseling and planning for the anticoagulated traveler's trip. PMID:26186419

  3. Aviation fuel property effects on altitude relight

    NASA Technical Reports Server (NTRS)

    Venkataramani, K.

    1987-01-01

    The major objective of this experimental program was to investigate the effects of fuel property variation on altitude relight characteristics. Four fuels with widely varying volatility properties (JP-4, Jet A, a blend of Jet A and 2040 Solvent, and Diesel 2) were tested in a five-swirl-cup-sector combustor at inlet temperatures and flows representative of windmilling conditions of turbofan engines. The effects of fuel physical properties on atomization were eliminated by using four sets of pressure-atomizing nozzles designed to give the same spray Sauter mean diameter (50 + or - 10 micron) for each fuel at the same design fuel flow. A second series of tests was run with a set of air-blast nozzles. With comparable atomization levels, fuel volatility assumes only a secondary role for first-swirl-cup lightoff and complete blowout. Full propagation first-cup blowout were independent of fuel volatility and depended only on the combustor operating conditions.

  4. A Daytime Aspect Camera for Balloon Altitudes

    NASA Technical Reports Server (NTRS)

    Dietz, Kurt L.; Ramsey, Brian D.; Alexander, Cheryl D.; Apple, Jeff A.; Ghosh, Kajal K.; Swift, Wesley R.; Six, N. Frank (Technical Monitor)

    2001-01-01

    We have designed, built, and flight-tested a new star camera for daytime guiding of pointed balloon-borne experiments at altitudes around 40km. The camera and lens are commercially available, off-the-shelf components, but require a custom-built baffle to reduce stray light, especially near the sunlit limb of the balloon. This new camera, which operates in the 600-1000 nm region of the spectrum, successfully provided daytime aspect information of approximately 10 arcsecond resolution for two distinct star fields near the galactic plane. The detected scattered-light backgrounds show good agreement with the Air Force MODTRAN models, but the daytime stellar magnitude limit was lower than expected due to dispersion of red light by the lens. Replacing the commercial lens with a custom-built lens should allow the system to track stars in any arbitrary area of the sky during the daytime.

  5. Daytime Aspect Camera for Balloon Altitudes

    NASA Technical Reports Server (NTRS)

    Dietz, Kurt L.; Ramsey, Brian D.; Alexander, Cheryl D.; Apple, Jeff A.; Ghosh, Kajal K.; Swift, Wesley R.

    2002-01-01

    We have designed, built, and flight-tested a new star camera for daytime guiding of pointed balloon-borne experiments at altitudes around 40 km. The camera and lens are commercially available, off-the-shelf components, but require a custom-built baffle to reduce stray light, especially near the sunlit limb of the balloon. This new camera, which operates in the 600- to 1000-nm region of the spectrum, successfully provides daytime aspect information of approx. 10 arcsec resolution for two distinct star fields near the galactic plane. The detected scattered-light backgrounds show good agreement with the Air Force MODTRAN models used to design the camera, but the daytime stellar magnitude limit was lower than expected due to longitudinal chromatic aberration in the lens. Replacing the commercial lens with a custom-built lens should allow the system to track stars in any arbitrary area of the sky during the daytime.

  6. High Altitude Supersonic Decelerator Test Vehicle

    NASA Technical Reports Server (NTRS)

    Cook, Brant T.; Blando, Guillermo; Kennett, Andrew; Von Der Heydt, Max; Wolff, John Luke; Yerdon, Mark

    2013-01-01

    The Low Density Supersonic Decelerator (LDSD) project is tasked by NASA's Office of the Chief Technologist (OCT) to advance the state of the art in Mars entry and descent technology in order to allow for larger payloads to be delivered to Mars at higher altitudes with better accuracy. The project will develop a 33.5 m Do Supersonic Ringsail (SSRS) parachute, 6m attached torus, robotic class Supersonic Inflatable Aerodynamic Decelerator (SIAD-R), and an 8 m attached isotensoid, exploration class Supersonic Inflatable Aerodynamic Decelerator (SIAD-E). The SSRS and SIAD-R should be brought to TRL-6, while the SIAD-E should be brought to TRL-5. As part of the qualification and development program, LDSD must perform a Mach-scaled Supersonic Flight Dynamics Test (SFDT) in order to demonstrate successful free flight dynamic deployments at Mars equivalent altitude, of all three technologies. In order to perform these tests, LDSD must design and build a test vehicle to deliver all technologies to approximately 180,000 ft and Mach 4, deploy a SIAD, free fly to approximately Mach 2, deploy the SSRS, record high-speed and high-resolution imagery of both deployments, as well as record data from an instrumentation suite capable of characterizing the technology induced vehicle dynamics. The vehicle must also be recoverable after splashdown into the ocean under a nominal flight, while guaranteeing forensic data protection in an off nominal catastrophic failure of a test article that could result in a terminal velocity, tumbling water impact.

  7. Uav Borne Low Altitude Photogrammetry System

    NASA Astrophysics Data System (ADS)

    Lin, Z.; Su, G.; Xie, F.

    2012-07-01

    In this paper,the aforementioned three major aspects related to the Unmanned Aerial Vehicles (UAV) system for low altitude aerial photogrammetry, i.e., flying platform, imaging sensor system and data processing software, are discussed. First of all, according to the technical requirements about the least cruising speed, the shortest taxiing distance, the level of the flight control and the performance of turbulence flying, the performance and suitability of the available UAV platforms (e.g., fixed wing UAVs, the unmanned helicopters and the unmanned airships) are compared and analyzed. Secondly, considering the restrictions on the load weight of a platform and the resolution pertaining to a sensor, together with the exposure equation and the theory of optical information, the principles of designing self-calibration and self-stabilizing combined wide-angle digital cameras (e.g., double-combined camera and four-combined camera) are placed more emphasis on. Finally, a software named MAP-AT, considering the specialty of UAV platforms and sensors, is developed and introduced. Apart from the common functions of aerial image processing, MAP-AT puts more effort on automatic extraction, automatic checking and artificial aided adding of the tie points for images with big tilt angles. Based on the recommended process for low altitude photogrammetry with UAVs in this paper, more than ten aerial photogrammetry missions have been accomplished, the accuracies of Aerial Triangulation, Digital orthophotos(DOM)and Digital Line Graphs(DLG) of which meet the standard requirement of 1:2000, 1:1000 and 1:500 mapping.

  8. Cluster II Mid-Altitude Cusp Observations

    NASA Astrophysics Data System (ADS)

    Winningham, J. D.

    2002-05-01

    Thirty plus years after its discovery the cusp is still an enigma. Questions such as is it open, closed, or mixed; where does it map; what constitutes a cusp etc still abound. Cusps have been defined on the basis of satellite, rocket, and ground based data from single and multiple sensor types. Cartoons and detailed models have been put forward to define what constitutes a cusp. An equal number of questions abound relative to the role the cusp plays in magnetospheric dynamics, mass and momentum transfer, and even energization to populate the rest of the magnetosphere. In a recent series of papers Savin et al have presented both Interball and Prognoz results in the high altitude cusp and sash region. In these papers they divide the high cusp into several new regions. They have an outer throat (OT) exterior to the MP with field lines connected to the earth and heated, stagnant plasma, a turbulent boundary layer (TBL) just at and outside the MP, an outer cusp (OC) that is inside the MP. They state an indentation depth of 1-2 RE. In the TBL large amplitude, low-frequency waves are observed. We will present multi-instrument/satellite Cluster II data that indicates the depth of the OT may be much deeper than thought by Savin. This stems from the higher spatial temporal resolution available from Cluster. Mid altitudes (~5RE) passes will be shown that exhibit the same morphology as Savin. This leads to a new definition of the cusp as the focus of open magnetopause current layer field lines.

  9. Evaluation of changes in snow water equivalent in different altitude zones

    NASA Astrophysics Data System (ADS)

    Kotríková, Katarína; Hlavčová, Kamila; Szolgay, Ján

    2015-04-01

    Snow cover is specific for its seasonality in Slovakia; the data of the snow cover have been collected since the middle of the 20th century. In this work we evaluated the snow cover and its change in the basins in Slovakia by the measured data and modelled data of the decade 1961 - 2010. The semi-distributed model derived from the concept of the HBV was used. The model was adapted for the simulation of the snow water equivalent (SWE) at different altitude zones. The input data were the mean daily values of the air temperature, the mean daily precipitation, and the mean daily discharges at the outlet point of the catchment. The zones' daily rainfall was processed by the interpolation method of inverse distance weighting; the zones' average air temperature values were calculated by linear regression between the stations' mean daily air temperatures and the altitudes of the stations. The daily evapotranspiration values were calculated by the Blaney-Criddle method. The calculations were based on the basin's average daily air temperature and the sunshine index of the river basin. The input data were divided into five altitude zones and the area' dimensions were set according to the five altitude zones. The next step was the validation of the simulated SWE with the measured data. We compared the simulated daily values in each altitude zone, which represent the zone's average data, with the measured value of the SWE for the mean altitude of each zone. There is a satisfactory degree of compliance between the daily simulated and measured SWE values. The changes in the simulated SWE were evaluated by comparing the mean, minimum and maximum daily values of SWE in each altitude zone. There is a decreasing trend in the values of the snow water equivalent in recent decades. Also, the trend was confirmed by a non-parametric Mann-Kendall test. The adapted rainfall-runoff model provides detailed output data, which contributes to increasing the level of accuracy of the modelling of

  10. 40 CFR 721.9504 - Silane, triethoxy (3,3,4,4,5,5, 6,6,7,7,8,8,8-tridecafluorooctyl)-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Silane, triethoxy (3,3,4,4,5,5, 6,6,7... Significant New Uses for Specific Chemical Substances § 721.9504 Silane, triethoxy (3,3,4,4,5,5, 6,6,7,7,8,8,8... substance identified as silane, triethoxy (3,3,4,4,5, 5,6,6,7,7,8,8,8-tridecafluorooctyl)- (PMN...

  11. 40 CFR 721.9504 - Silane, triethoxy (3,3,4,4,5,5, 6,6,7,7,8,8,8-tridecafluorooctyl)-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Silane, triethoxy (3,3,4,4,5,5, 6,6,7... Significant New Uses for Specific Chemical Substances § 721.9504 Silane, triethoxy (3,3,4,4,5,5, 6,6,7,7,8,8,8... substance identified as silane, triethoxy (3,3,4,4,5, 5,6,6,7,7,8,8,8-tridecafluorooctyl)- (PMN...

  12. 40 CFR 721.9504 - Silane, triethoxy (3,3,4,4,5,5, 6,6,7,7,8,8,8-tridecafluorooctyl)-.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Silane, triethoxy (3,3,4,4,5,5, 6,6,7... Significant New Uses for Specific Chemical Substances § 721.9504 Silane, triethoxy (3,3,4,4,5,5, 6,6,7,7,8,8,8... substance identified as silane, triethoxy (3,3,4,4,5, 5,6,6,7,7,8,8,8-tridecafluorooctyl)- (PMN...

  13. 40 CFR 721.9504 - Silane, triethoxy (3,3,4,4,5,5, 6,6,7,7,8,8,8-tridecafluorooctyl)-.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Silane, triethoxy (3,3,4,4,5,5, 6,6,7... Significant New Uses for Specific Chemical Substances § 721.9504 Silane, triethoxy (3,3,4,4,5,5, 6,6,7,7,8,8,8... substance identified as silane, triethoxy (3,3,4,4,5, 5,6,6,7,7,8,8,8-tridecafluorooctyl)- (PMN...

  14. 40 CFR 721.9504 - Silane, triethoxy (3,3,4,4,5,5, 6,6,7,7,8,8,8-tridecafluorooctyl)-.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Silane, triethoxy (3,3,4,4,5,5, 6,6,7... Significant New Uses for Specific Chemical Substances § 721.9504 Silane, triethoxy (3,3,4,4,5,5, 6,6,7,7,8,8,8... substance identified as silane, triethoxy (3,3,4,4,5, 5,6,6,7,7,8,8,8-tridecafluorooctyl)- (PMN...

  15. Transient Luminosity along Negative Stepped Leaders in Lightning

    NASA Astrophysics Data System (ADS)

    Stolzenburg, Maribeth; Marshall, Thomas; Karunarathne, Sumedhe; Karunarathna, Nadeeka; Orville, Richard

    2016-04-01

    We present observations of abandoned stepped leader branches that briefly reconnect to the main stepped leader trunk or another active branch during the negative stepped leader advance in natural cloud-to-ground lightning strokes. The transient luminous features described, termed sparks, are common, bright and fast based on high-speed video data with 20 us image interval. Sparks typically reach maximum visible extent of a few hundred meters or less and peak intensity of one to three times that of their parent leader within 40 us. Most sparks connect to a parent leader within their first 20 us and are visible for less than 120 us. Generally, there are several milliseconds (average 3.3 ms) before the spark during which its branch is visibly abandoned, i.e., apparently neither propagating nor connected to the active stepped leader system. There is a tendency for sparks to occur late in the stepped leader advance, averaging 900 us before the return stroke for 90 sparks in 14 strokes. Sparks occur at altitudes at least as high as the visible stepped leader top (about 3000 m in these data), but they have not been observed below 500 m altitude. Parent leaders typically get brighter below the connection point after the spark, and in some cases their speed of advance increases. Nearby time-correlated electric field change data show a distinct spark signature characterized by a relatively large bipolar pulse, followed by a slower decrease over 40-100 us, ending with another relatively large pulse.

  16. 5,6-EET Is Released upon Neuronal Activity and Induces Mechanical Pain Hypersensitivity via TRPA1 on Central Afferent Terminals

    PubMed Central

    Sisignano, Marco; Park, Chul-Kyu; Angioni, Carlo; Zhang, Dong Dong; von Hehn, Christian; Cobos, Enrique J.; Ghasemlou, Nader; Xu, Zhen-Zhong; Kumaran, Vigneswara; Lu, Ruirui; Grant, Andrew; Fischer, Michael J. M.; Schmidtko, Achim; Reeh, Peter; Ji, Ru-Rong; Woolf, Clifford J.; Geisslinger, Gerd; Scholich, Klaus; Brenneis, Christian

    2012-01-01

    Epoxyeicosatrienoic acids (EETs) are cytochrome P450-epoxygenase-derived metabolites of arachidonic acid that act as endogenous signaling molecules in multiple biological systems. Here we have investigated the specific contribution of 5,6-EET to transient receptor potential (TRP) channel activation in nociceptor neurons and its consequence for nociceptive processing. We found that, during capsaicin-induced nociception, 5,6-EET levels increased in dorsal root ganglia (DRGs) and the dorsal spinal cord, and 5,6-EET is released from activated sensory neurons in vitro. 5,6-EET potently induced a calcium flux (100 nm) in cultured DRG neurons that was completely abolished when TRPA1 was deleted or inhibited. In spinal cord slices, 5,6-EET dose dependently enhanced the frequency, but not the amplitude, of spontaneous EPSCs (sEPSCs) in lamina II neurons that also responded to mustard oil (allyl isothiocyanate), indicating a presynaptic action. Furthermore, 5,6-EET-induced enhancement of sEPSC frequency was abolished in TRPA1-null mice, suggesting that 5,6-EET presynaptically facilitated spinal cord synaptic transmission by TRPA1. Finally, in vivo intrathecal injection of 5,6-EET caused mechanical allodynia in wild-type but not TRPA1-null mice. We conclude that 5,6-EET is synthesized on the acute activation of nociceptors and can produce mechanical hypersensitivity via TRPA1 at central afferent terminals in the spinal cord. PMID:22553041

  17. On the contribution of stereochemistry to human ITPK1 specificity: Ins(1,4,5,6)P4 is not a physiologic substrate.

    PubMed

    Riley, Andrew M; Deleu, Sandrine; Qian, Xun; Mitchell, Jennifer; Chung, Sung-Kee; Adelt, Stephan; Vogel, Günter; Potter, Barry V L; Shears, Stephen B

    2006-01-01

    Ins(1,4,5,6)P4, a biologically active cell constituent, was recently advocated as a substrate of human Ins(3,4,5,6)P4 1-kinase (hITPK1), because stereochemical factors were believed relatively unimportant to specificity [Miller, G.J., Wilson, M.P., Majerus, P.W. and Hurley, J.H. (2005) Specificity determinants in inositol polyphosphate synthesis: crystal structure of inositol 1,3,4-triphosphate 5/6-kinase. Mol. Cell. 18, 201-212]. Contrarily, we provide three examples of hITPK1 stereospecificity. hITPK1 phosphorylates only the 1-hydroxyl of both Ins(3,5,6)P3 and the meso-compound, Ins(4,5,6)P3. Moreover, hITPK1 has >13,000-fold preference for Ins(3,4,5,6)P4 over its enantiomer, Ins(1,4,5,6)P4. The biological significance of hITPK1 being stereospecific, and not physiologically phosphorylating Ins(1,4,5,6)P4, is reinforced by our demonstrating that Ins(1,4,5,6)P4 is phosphorylated (K(m) = 0.18 microM) by inositolphosphate-multikinase. PMID:16376887

  18. Stepped-to-dart leaders preceding lightning return strokes

    NASA Astrophysics Data System (ADS)

    Stolzenburg, Maribeth; Marshall, Thomas C.; Karunarathne, Sumedhe; Karunarathna, Nadeeka; Warner, Tom A.; Orville, Richard E.

    2013-09-01

    time-correlated high-speed video and electric field change data, three cases are described in which dart leaders toward ground are immediately preceded by stepped leaders that find and use previously used channels. These "stepped-to-dart leaders" occur in three natural negative ground flashes. Prior to the stepped-to-dart connection, the leaders have characteristics of stepped leaders, including average two-dimensional speeds of 1.6-2.7 × 105 m s-1 (visible from 5.5, 3.4, and 0.9 km altitude). After the connection, they behave as dart (or dart-stepped) leaders, with larger amplitude E-change pulses and faster average speeds of 3.4-7.8 × 106 m s-1. Connection altitudes are 3.32, 1.57, and 0.75 km. Immediately after the connection, there is a brief lighting in a short part of the prior return stroke channel. Luminosity travels up the stepped leader path after the connection, while the dart leader proceeds toward ground. In two cases, all the strokes subsequent to the stepped-to-dart stroke follow the visible portion of its channel. The other case has two subsequent strokes which do not reuse any portion of the stepped-to-dart channel. For the other 12 strokes in these flashes, stepped leader average speeds range from 1.7 to 3.0 × 105 m s-1, and dart leader average speeds are 0.82 to 16.67 × 106 m s-1. Overall, the return stroke waveforms give reasonable indication of the type of leader that preceded the stroke. Stepped-to-dart leaders are apparently rare in optical data, occurring in about 1% of subsequent strokes and 2.5% of flashes.

  19. The Twelve Steps Experientially.

    ERIC Educational Resources Information Center

    Horne, Lianne

    Experiential activities provide each participant with the ability to see, feel, and experience whatever therapeutic issue the facilitator is addressing, and usually much more. This paper presents experiential activities to address the 12 steps of recovery adopted from Alcoholics Anonymous. These 12 steps are used worldwide for many other recovery…

  20. STEP Experiment Requirements

    NASA Technical Reports Server (NTRS)

    Brumfield, M. L. (Compiler)

    1984-01-01

    A plan to develop a space technology experiments platform (STEP) was examined. NASA Langley Research Center held a STEP Experiment Requirements Workshop on June 29 and 30 and July 1, 1983, at which experiment proposers were invited to present more detailed information on their experiment concept and requirements. A feasibility and preliminary definition study was conducted and the preliminary definition of STEP capabilities and experiment concepts and expected requirements for support services are presented. The preliminary definition of STEP capabilities based on detailed review of potential experiment requirements is investigated. Topics discussed include: Shuttle on-orbit dynamics; effects of the space environment on damping materials; erectable beam experiment; technology for development of very large solar array deployers; thermal energy management process experiment; photovoltaic concentrater pointing dynamics and plasma interactions; vibration isolation technology; flight tests of a synthetic aperture radar antenna with use of STEP.

  1. Effects of Ascent to High Altitude on Human Antimycobacterial Immunity

    PubMed Central

    Aldridge, Robert W.; Siedner, Mark J.; Necochea, Alejandro; Leybell, Inna; Valencia, Teresa; Herrera, Beatriz; Wiles, Siouxsie; Friedland, Jon S.; Gilman, Robert H.; Evans, Carlton A.

    2013-01-01

    Background Tuberculosis infection, disease and mortality are all less common at high than low altitude and ascent to high altitude was historically recommended for treatment. The immunological and mycobacterial mechanisms underlying the association between altitude and tuberculosis are unclear. We studied the effects of altitude on mycobacteria and antimycobacterial immunity. Methods Antimycobacterial immunity was assayed in 15 healthy adults residing at low altitude before and after they ascended to 3400 meters; and in 47 long-term high-altitude residents. Antimycobacterial immunity was assessed as the extent to which participants’ whole blood supported or restricted growth of genetically modified luminescent Bacille Calmette-Guérin (BCG) mycobacteria during 96 hours incubation. We developed a simplified whole blood assay that could be used by a technician in a low-technology setting. We used this to compare mycobacterial growth in participants’ whole blood versus positive-control culture broth and versus negative-control plasma. Results Measurements of mycobacterial luminescence predicted the number of mycobacterial colonies cultured six weeks later. At low altitude, mycobacteria grew in blood at similar rates to positive-control culture broth whereas ascent to high altitude was associated with restriction (p≤0.002) of mycobacterial growth to be 4-times less than in culture broth. At low altitude, mycobacteria grew in blood 25-times more than negative-control plasma whereas ascent to high altitude was associated with restriction (p≤0.01) of mycobacterial growth to be only 6-times more than in plasma. There was no evidence of differences in antimycobacterial immunity at high altitude between people who had recently ascended to high altitude versus long-term high-altitude residents. Conclusions An assay of luminescent mycobacterial growth in whole blood was adapted and found to be feasible in low-resource settings. This demonstrated that ascent to or

  2. Photographic observations of streamers and steps in a cloud-to-air negative leader

    NASA Astrophysics Data System (ADS)

    Edens, H. E.; Eack, K. B.; Rison, W.; Hunyady, S. J.

    2014-02-01

    A color photograph has been obtained of a negative lightning leader in clear air at 10.3 km altitude. The individual leader steps are resolved as relatively straight segments of at least ~200 m in length, between sharp kinks (nodes) in the channel. Each node is accompanied by a group of streamers of ~100 m in length. One node has an unconnected secondary leader with streamers at both ends. Lightning Mapping Array observations show that the leader was part of an intracloud (IC) flash. The observation shows that steps of negative leaders near 10 km altitude are an order of magnitude longer than values reported in the literature for negative leaders near sea level. Since negative leaders propagate at comparable velocities at low and high altitudes, stepping occurs at a lower rate in IC flashes, which can explain why RF emissions from IC flashes are more intermittent than those from cloud-to-ground flashes.

  3. Ventilation during simulated altitude, normobaric hypoxia and normoxic hypobaria

    NASA Technical Reports Server (NTRS)

    Loeppky, J. A.; Icenogle, M.; Scotto, P.; Robergs, R.; Hinghofer-Szalkay, H.; Roach, R. C.; Leoppky, J. A. (Principal Investigator)

    1997-01-01

    To investigate the possible effect of hypobaria on ventilation (VE) at high altitude, we exposed nine men to three conditions for 10 h in a chamber on separate occasions at least 1 week apart. These three conditions were: altitude (PB = 432, FIO2 = 0.207), normobaric hypoxia (PB = 614, FIO2 = 0.142) and normoxic hypobaria (PB = 434, FIO2 = 0.296). In addition, post-test measurements were made 2 h after returning to ambient conditions at normobaric normoxia (PB = 636, FIO2 = 0.204). In the first hour of exposure VE was increased similarly by altitude and normobaric hypoxia. The was 38% above post-test values and end-tidal CO2 (PET(CO2) was lower by 4 mmHg. After 3, 6 and 9 h, the average VE in normobaric hypoxia was 26% higher than at altitude (p < 0.01), resulting primarily from a decline in VE at altitude. The difference between altitude and normobaric hypoxia was greatest at 3 h (+ 39%). In spite of the higher VE during normobaric hypoxia, the PET(CO2) was higher than at altitude. Changes in VE and PET(CO2) in normoxic hypobaria were minimal relative to normobaric normoxia post-test measurements. One possible explanation for the lower VE at altitude is that CO2 elimination is relatively less at altitude because of a reduction in inspired gas density compared to normobaric hypoxia; this may reduce the work of breathing or alveolar deadspace. The greater VE during the first hour at altitude, relative to subsequent measurements, may be related to the appearance of microbubbles in the pulmonary circulation acting to transiently worsen matching. Results indicate that hypobaria per se effects ventilation under altitude conditions.

  4. Improving oxygenation at high altitude: acclimatization and O2 enrichment.

    PubMed

    West, John B

    2003-01-01

    When lowlanders go to high altitude, the resulting oxygen deprivation impairs mental and physical performance, quality of sleep, and general well-being. This paper compares the effects of ventilatory acclimatization and oxygen enrichment of room air on the improvement of oxygenation as judged by the increase in the alveolar P(O2) and the reduction in equivalent altitude. The results show that, on the average, complete ventilatory acclimatization at an altitude of 5000 m increases the alveolar P(O2) by nearly 8 torr, which corresponds to a reduction in equivalent altitude of about 1000 m, although there is considerable individual variability. By comparison, oxygen enrichment to 27% at 5000 m can easily reduce the equivalent altitude to 3200 m, which is generally well tolerated. Because full ventilatory acclimatization at altitudes up to about 3600 m reduces the equivalent altitude to about 3000 m, oxygen enrichment is not justified for well-acclimatized persons. At an altitude of 4200 m, where several telescopes are located on the summit of Mauna Kea, full acclimatization reduces the equivalent altitude to about 3400 m, but the pattern of commuting probably would not allow this. Therefore, at this altitude, oxygen enrichment would be beneficial but is not essential. At higher altitudes such as 5050 m, where other telescopes are located or planned, the gain in oxygenation from acclimatization is insufficient to produce an adequate mental or physical performance for most work, and oxygen enrichment is highly desirable. Full ventilatory acclimatization requires at least a week of continuous exposure, although much of the improvement is seen in the first 2 days. PMID:14561244

  5. The stereochemical outcome of electrophilic addition reactions on the 5,6-double bond in the spinosyns.

    PubMed

    De Amicis, C V; Graupner, P R; Erickson, J A; Paschal, J W; Kirst, H A; Creemer, L C; Fanwick, P E

    2001-12-14

    The electrophilic addition of reagents to the 5,6-double bond in spinosyn A and spinosyn D systems occurred with high pi-diastereofacial selectivity. Addition occurred preferentially from the beta face of the molecule with selectivities ranging from 5:1 to better than 30:1. Various NMR properties were investigated in order to distinguish the beta and alpha isomers with the help of theoretical models of the products. These NMR properties include a (13)C gamma effect to C-11 and vicinal coupling between H-4 and H-5. To help rationalize the selectivity, computational studies on the transition states for epoxidation were calculated using density functional theory. The results indicate that beta epoxidation is favored and that the geometries of the transition structures are consistent with torsional steering being the source of the selectivity. PMID:11735521

  6. Flexible charge balanced stimulator with 5.6 fC accuracy for 140 nC injections.

    PubMed

    Nag, Sudip; Jia, Xiaofeng; Thakor, Nitish V; Sharma, Dinesh

    2013-06-01

    Electrical stimulations of neuronal structures must ensure net injected charges to be zero for biological safety and voltage compliance reasons. We present a novel architecture of general purpose biphasic constant current stimulator that exhibits less than 5.6 fC error while injecting 140 nC charges using 1.4 mA currents. The floating current sources and conveyor switch based system can operate in monopolar or bipolar modes. Anodic-first or cathodic-first pulses with optional inter-phase delays have been demonstrated with zero quiescent current requirements at the analog front-end. The architecture eliminates blocking capacitors, electrode shorting and complex feedbacks. Bench-top and in-vivo measurement results have been presented with emulated electrode impedances (resistor-capacitor network), Ag-AgCl electrodes in saline and in-vivo (acute) peripheral nerve stimulations in anesthetized rats. PMID:23853326

  7. Synthesis of 1,4,5,6-tetrahydropyridine derivatives starting from trans-3-chloro-1,3-alkadien-5-ones

    SciTech Connect

    Melikyan, G.G.; Atanesyan, K.A.; Aslanyan, G.Kh.; Tirakyan, M.R.; Khachatryan, L.A.; Badanyan, Sh.O.

    1987-10-01

    A method has been developed for the synthesis of 3-carbethoxy-2-methyl-6-(oxo-alkylidene)-1,4,5,6-tetrahydropyridines by reaction of trans-3-chloro-1,3-alkadien-5-ones with ethyl aminocrotonate. It is shown that the corresponding vinylacetylanic ketones are intermediate products of the reactions. PMR spectra in CCl/sub 4/ were obtained on a Perkin-Elmer R12B (60 MHz) spectrometer, with TMS as internal standard. /sup 13/C NMR spectra were recordeed on a Bruker WH-90 instrument (22.63 MHz) without suppression and with complete suppression of spin-spin coupling. IR spectra were recorded in CCl/sub 4/ on a UR-10 instrument, mass spectra were recorded on a MX-1303 spectrometer with electron ionization energy of 30 eV.

  8. Bioconcentration of 5,5',6-trichlorobiphenyl and pentachlorophenol in the midge, Chironomus riparius, as measured by a pharmacokinetic model

    USGS Publications Warehouse

    Lydy, M.J.; Hayton, W.L.; Staubus, A.E.; Fisher, S.W.

    1994-01-01

    A two compartment pharmacokinetic model was developed which describes the uptake and elimination of 5,5',6-trichlorobiphenyl (TCB) and pentachlorophenol (PCP) in the midge, Chironomus riparius. C. riparius were exposed to nominal TCB (2 ??g L-1) and PCP (9 ??g L-1) concentrations during a 16 h static uptake phase. Depuration was determined over approximately 45 h using a flowthrough system without feeding. The uptake clearance (P) was 330 ?? 61 ml g-1 midge h-1 for TCB and 55 ?? 4 ml g-1 midge h-1 for PCP, while measured bioconcentration factors (BCF) were 35,900 and 458 for TCB and PCP, respectively. Overall, the clearance-volume- based pharmacokinetic model predicted BCF values that were consistent with published values as well as with BCF values obtained from the octanol-water partition coefficient (K(ow)).

  9. New 2-phenyl-4,5,6,7-tetrahydro-2H-indazole derivatives as paddy field herbicides.

    PubMed

    Hwang, In Taek; Kim, Hyoung Rae; Jeon, Dong Ju; Hong, Kyung Sik; Song, Jong Hwan; Chung, Chang Kook; Cho, Kwang Yun

    2005-05-01

    A series of 3-chloro-2-(4-chloro-2-fluorophenyl)-4,5,6,7-tetrahydro-2H-indazole derivatives containing various substituted isoxazolinylmethoxy groups at the 5-position of the benzene ring were synthesized and their herbicidal activities assessed under greenhouse and flooded paddy conditions. Among them, compounds having a phenyl or cyano substituent at the 3-position of the 5-methyl-isoxazolin-5-yl structure demonstrated good rice selectivity and potent herbicidal activity against annual weeds at 16-63 g AI ha(-1) under greenhouse conditions. Field trials indicated that these two compounds controlled a wide range of annual weeds rapidly with a good tolerance on transplanted rice seedlings by pre-emergence application. They showed a low mammalian and environmental toxicity in various toxicological tests. PMID:15627239

  10. SAMS Acceleration Measurements on Mir from May 1997 to June 1998 (NASA Increments 5, 6, and 7)

    NASA Technical Reports Server (NTRS)

    DeLombard, Richard

    1999-01-01

    During NASA Increments 5, 6, and 7 (May 1997 to June 1998), about eight gigabytes of acceleration data were collected by the Space Acceleration Measurement System (SAMS) onboard the Russian Space Station Mir. The data were recorded on twenty-seven optical disks which were returned to Earth on Orbiter missions STS-86, STS-89, and STS-91. During these increments, SAMS data were collected in the Priroda module to support various microgravity experiments. This report points out some of the salient features of the microgravity acceleration environment to which the experiments were exposed. This report presents an overview of the SAMS acceleration measurements recorded by 10 Hz and 100 Hz sensor heads. The analyses included herein complement those presented in previous Mir increment summary reports prepared by the Principal Investigator Microgravity Services project.

  11. Design, Synthesis and Evaluation of Novel 2,5,6-Trisubstituted Benzimidazoles Targeting FtsZ as Antitubercular Agents

    PubMed Central

    Park, Bora; Awasthi, Divya; Chowdhury, Soumya R.; Melief, Eduard H.; Kumar, Kunal; Knudson, Susan E.; Slayden, Richard A.; Ojima, Iwao

    2014-01-01

    Filamenting temperature-sensitive protein Z (FtsZ), an essential cell division protein, is a promising target for the drug discovery of new-generation antibacterial agents against various bacterial pathogens. As a part of SAR studies on benzimidazoles, we have synthesized a library of 376 novel 2,5,6-trisubstituted benzimidazoles, bearing ether or thioether linkage at the 6-position. In a preliminary HTP screening against Mtb H37Rv, 108 compounds were identified as hits at a cut off concentration of 5 μg/mL. Among those hits, 10 compounds exhibited MIC values in the range of 0.63–12.5 μg/mL. Light scattering assay and TEM analysis with the most potent compound 5a clearly indicate that its molecular target is Mtb-FtsZ. Also, the Kd of 5a with Mtb-FtsZ was determined to be 1.32 μM. PMID:24726304

  12. Spark-Plasma Sintering of W-5.6Ni-1.4Fe Heavy Alloys: Densification and Grain Growth

    NASA Astrophysics Data System (ADS)

    Hu, Ke; Li, Xiaoqiang; Qu, Shengguan; Li, Yuanyuan

    2013-02-01

    W-5.6Ni-1.4Fe heavy alloys were prepared by the method of spark-plasma sintering, and the densification and grain growth kinetics were analyzed as a function of various parameters such as sintering temperature and dwell duration. It is found that the local temperature gradient at the vicinity of the pores can cause the matrix phase melting or softening, resulting in a viscous layer coating the W particles and an improved solubility of W into the matrix phase. In the initial stage, particle rearrangement and neck formation and growth take place, and γ-(Ni, Fe) matrix phase has formed. Dissolution-precipitation and Ni-enhanced W grain boundary diffusion together with viscous process contribute to the simultaneous densification and grain growth in the intermediate stage. During the final stage, fast grain growth, controlled by both gas-phase diffusion and dissolution-precipitation mechanisms, dominates over the densification.

  13. Spectrofluorimetric determination of nitric oxide at trace levels with 5,6-diamino-1,3-naphthalene disulfonic acid.

    PubMed

    Zhang, Xian; Wang, Hong; Liang, Shu-Cai; Zhang, Hua-Shan

    2002-03-01

    Based on the selective reaction that 5,6-diamino-1,3-naphthalene disulfonic acid (DANDS) traps nitric oxide (NO) in the presence of dioxygen to yield the highly fluorescent form, 1-[H]-naphthotriazole-6,8-disulfonic acid in moderately alkaline medium, a new spectrofluorimetric method for the determination of NO has been reported. The method offered the advantage of specificity, sensitivity and a simple protocol for the direct detection of NO in aqueous solution. The linear calibration range for NO was 0.04-1.44 mumoll(-1) with a 3sigma detection limit of 0.6 nmoll(-1). The proposed method has been used to monitor the release of NO from S-nitrosocysteine, a NO-releasing agent. PMID:18968522

  14. Structure-based discovery of novel 4,5,6-trisubstituted pyrimidines as potent covalent Bruton's tyrosine kinase inhibitors.

    PubMed

    Zou, Yi; Xiao, Jianhu; Tu, Zhengchao; Zhang, Yingyi; Yao, Kun; Luo, Minghao; Ding, Ke; Zhang, Yihua; Lai, Yisheng

    2016-07-01

    A series of novel 4,5,6-trisubstituted pyrimidines were designed as potent covalent Bruton's tyrosine kinase (BTK) inhibitors based on the structure of ibrutinib by using a ring-opening strategy. Among these derivatives, compound I1 exhibited the most potent inhibitory activity with an IC50 value of 0.07μM. The preliminary structure-activity relationship was discussed and the primary amino group at the C-4 position of pyrimidine was crucial for maintaining BTK activity. Furthermore, molecular dynamics simulations and binding free energy calculations were performed for three inhibitor-BTK complexes to determine the probable binding model, which provided a comprehensive guide for further structural modification and optimization. PMID:27210433

  15. Histopathological characterization of renal tubular and interstitial changes in 5/6 nephrectomized marmoset monkeys (Callithrix jacchus).

    PubMed

    Suzuki, Yui; Yamaguchi, Itaru; Myojo, Kensuke; Kimoto, Naoya; Imaizumi, Minami; Takada, Chie; Sanada, Hiroko; Takaba, Katsumi; Yamate, Jyoji

    2015-01-01

    Common marmosets (Callithrix jacchus) have become a useful animal model, particularly for development of biopharmaceuticals. While various renal failure models have been established in rodents, there is currently no acceptable model in marmosets. We analyzed the damaged renal tubules and tubulointerstitial changes (inflammation and fibrosis) of 5/6 nephrectomized (Nx) common marmosets by histopathological/immunohistochemical methods, and compared these findings to those in 5/6 Nx SD rats. In Nx marmosets and rats sacrificed at 5 and 13 weeks after Nx, variously dilated and atrophied renal tubules were seen in the cortex in common; however, the epithelial proliferating activity was much less in Nx marmosets. Furthermore, the degrees of inflammation and fibrosis seen in the affected cortex were more severe and massive in Nx marmosets with time-dependent increase. Interestingly, inflammation in Nx marmosets, of which degree was less in Nx rats, consisted of a large number of CD3-positive T cells and CD20-positive B cells (occasionally forming follicles), and a few CD68-positive macrophages. Based on these findings, lymphocytes might contribute to the progressive renal lesions in Nx marmosets. Fibrotic areas in Nx marmosets comprised myofibroblasts expressing vimentin and α-smooth muscle actin (α-SMA), whereas along with vimentin and α-SMA expressions, desmin was expressed in myofibroblasts in Nx rats. This study shows that there are some differences in renal lesions induced by Nx between marmosets and rats, which would provide useful, base-line information for pharmacology and toxicology studies using Nx marmosets. PMID:25446802

  16. Synthesis and antinociceptive activity of new 2-substituted 4-(trifluoromethyl)-5,6-dihydrobenzo[h]quinazolines.

    PubMed

    Bonacorso, Helio G; Rosa, Wilian C; Oliveira, Sara M; Brusco, Indiara; Pozza, Camila C Dalla; Nogara, Pablo A; Wiethan, Carson W; Rodrigues, Melissa B; Frizzo, Clarissa P; Zanatta, Nilo

    2016-10-01

    A useful synthetic route for an initial new series of 2-substituted 4-(trifluoromethyl)-5,6-dihydrobenzo[h]quinazolines (3), as well as an evaluation of their analgesic effect in a mice pain model, is reported. Five new quinazolines were formed from the cyclocondensation reactions of 2,2,2-trifluoro-1-(1-methoxy-1,2,3,4-tetrahydronaphthalen-2-yl)ethanone (1) with some well-known amidine salts [NH2CR(=NH)] (2), in which R=H, Me, Ph, NH2 and SMe, at a 40-70% yield. Subsequently, due to the importance of the pyrrole nucleus, a 2-(pyrrol-1-yl)quinazoline (4) was obtained through a Clauson-Kaas reaction from the respective 2-(amino)quinazoline, in a reaction with 2,5-dimethoxy-tetrahydrofuran. The analgesic evaluation demonstrated that four 5,6-dihydrobenzo[h]quinazolines (compounds of 3c (R=Ph), 3d (R=NH2), 3e (R=SMe), and 4 (R=pyrrol-1-yl); 100mg/kg, p.o.) and ketoprofen (100mg/kg, p.o.) significantly reduced the spontaneous nociception in a capsaicin-induced test. Moreover, in comparison with ketoprofen (100 and 300mg/kg, p.o.), compound 3c (30-300mg/kg, p.o.) showed an anti-hyperalgesic action in an arthritic pain model without locomotor alterations in the mice, suggesting that quinazoline 3c is a promising prototype scaffold for new analgesic drugs in the treatment of pathological pain such as that in arthritis. PMID:27561714

  17. Isolation of oligomers of 5,6-dihydroxyindole-2-carboxylic acid from the eye of the catfish.

    PubMed

    Ito, S; Nicol, J A

    1974-10-01

    The reflecting material of the tapetum lucidum of the sea catfish (Arius felis) was chromatographed on Sephadex LH-20 in methanol-dimethyl sulphoxide-formic acid. Two components were present: one, showing an absorption maximum at 330nm, was tapetal pigment; the other, at 257nm, was an associated nucleoside. The tapetal pigment was extracted in methanol-HCl and isolated by adsorption chromatography on Sephadex LH-20. It yielded a methoxy methyl ester on treatment with diazomethane, and permanganate oxidation gave pyrrole-2,3,5-tricarboxylic acid. From the information provided by u.v. and i.r. spectra of the pigment and its methoxy methyl ester, from elemental analyses and from the oxidation products, we suggest that the tapetal pigment is derived from oxidative coupling of 5,6-dihydroxyindole-2-carboxylic acid. A molecular-weight determination and chromatography of the methoxy methyl ester indicate that the pigment is a mixture of oligomers, among which the tetramers probably predominate. We consider that the monomers are joined mainly by C-C linkages at positions 4 and 7. A synthetic pigment having spectral properties nearly identical with those of the natural pigment was prepared by enzymic oxidation of 5,6-dihydroxyindole-2-carboxylic acid with mushroom tyrosinase. The identity of the tapetal pigment with the synthetic pigment was further confirmed by comparing u.v. and i.r. spectra of their methoxy methyl esters. Formation of the tapetal pigment from tyrosine and relationships of the tapetal pigment to melanin are discussed. PMID:4464851

  18. X- and gamma ray observations in high-altitude thunderstorms in Mexico

    NASA Astrophysics Data System (ADS)

    Kelley, N. A.; Smith, D. M.; Lara, A.

    2014-12-01

    High-energy emission from lightning is more easily measured at high altitudes, close to or within the electric fields accelerating the energetic particles. Gamma rays from long duration glows and x-rays from stepped leaders attenuate with distance. From mountaintops, it may be possible to measure an amplified version of the x-rays commonly seen from stepped leaders. These amplified x-rays could arise from the thunderstorm electric field multiplying the energetic particles via Relativistic Runaway Electron Avalanches (RREA). Amplified stepped leaders may be similar or even the same as terrestrial gamma-ray flashes (TGFs), which need long-range electric fields to produce the intensities seen from space. We deployed two gamma-ray detectors at the High Altitude Water Cherenkov (HAWC) Observatory site on the northeastern slope of the Sierra Negra near Puebla, Mexico at 4100 meters to search for amplified leader events and also for the minutes-long gamma-ray glows observed from thunderstorms by other groups from the ground, balloons, and aircraft. We will also examine the data from HAWC itself, a large array of water tanks viewed by photomultiplier tubes, to look for signals simultaneous with any in our scintillators. In principle, large Cherenkov detectors and small scintillators can give complementary data about the radiation field, emphasizing the total energy content and the number flux of particles, respectively. We will present results from the summer 2014 deployment and talk about future lightning gamma-ray detectors to be deployed at HAWC.

  19. Low-Altitude Operation of Unmanned Rotorcraft

    NASA Astrophysics Data System (ADS)

    Scherer, Sebastian

    Currently deployed unmanned rotorcraft rely on preplanned missions or teleoperation and do not actively incorporate information about obstacles, landing sites, wind, position uncertainty, and other aerial vehicles during online motion planning. Prior work has successfully addressed some tasks such as obstacle avoidance at slow speeds, or landing at known to be good locations. However, to enable autonomous missions in cluttered environments, the vehicle has to react quickly to previously unknown obstacles, respond to changing environmental conditions, and find unknown landing sites. We consider the problem of enabling autonomous operation at low-altitude with contributions to four problems. First we address the problem of fast obstacle avoidance for a small aerial vehicle and present results from over a 1000 rims at speeds up to 10 m/s. Fast response is achieved through a reactive algorithm whose response is learned based on observing a pilot. Second, we show an algorithm to update the obstacle cost expansion for path planning quickly and demonstrate it on a micro aerial vehicle, and an autonomous helicopter avoiding obstacles. Next, we examine the mission of finding a place to land near a ground goal. Good landing sites need to be detected and found and the final touch down goal is unknown. To detect the landing sites we convey a model based algorithm for landing sites that incorporates many helicopter relevant constraints such as landing sites, approach, abort, and ground paths in 3D range data. The landing site evaluation algorithm uses a patch-based coarse evaluation for slope and roughness, and a fine evaluation that fits a 3D model of the helicopter and landing gear to calculate a goodness measure. The data are evaluated in real-time to enable the helicopter to decide on a place to land. We show results from urban, vegetated, and desert environments, and demonstrate the first autonomous helicopter that selects its own landing sites. We present a generalized

  20. 14 CFR 91.119 - Minimum safe altitudes: General.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Minimum safe altitudes: General. 91.119... § 91.119 Minimum safe altitudes: General. Except when necessary for takeoff or landing, no person may... fails, an emergency landing without undue hazard to persons or property on the surface. (b)...

  1. 14 CFR 135.203 - VFR: Minimum altitudes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false VFR: Minimum altitudes. 135.203 Section 135... Operating Limitations and Weather Requirements § 135.203 VFR: Minimum altitudes. Except when necessary for... above the surface or less than 500 feet horizontally from any obstacle; or (2) At night, at an...

  2. 14 CFR 135.203 - VFR: Minimum altitudes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false VFR: Minimum altitudes. 135.203 Section 135... Operating Limitations and Weather Requirements § 135.203 VFR: Minimum altitudes. Except when necessary for... above the surface or less than 500 feet horizontally from any obstacle; or (2) At night, at an...

  3. 14 CFR 135.203 - VFR: Minimum altitudes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false VFR: Minimum altitudes. 135.203 Section 135... Operating Limitations and Weather Requirements § 135.203 VFR: Minimum altitudes. Except when necessary for... above the surface or less than 500 feet horizontally from any obstacle; or (2) At night, at an...

  4. 14 CFR 91.119 - Minimum safe altitudes: General.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Minimum safe altitudes: General. 91.119... § 91.119 Minimum safe altitudes: General. Except when necessary for takeoff or landing, no person may... fails, an emergency landing without undue hazard to persons or property on the surface. (b)...

  5. 14 CFR 91.119 - Minimum safe altitudes: General.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Minimum safe altitudes: General. 91.119... § 91.119 Minimum safe altitudes: General. Except when necessary for takeoff or landing, no person may... fails, an emergency landing without undue hazard to persons or property on the surface. (b)...

  6. 14 CFR 135.203 - VFR: Minimum altitudes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false VFR: Minimum altitudes. 135.203 Section 135... Operating Limitations and Weather Requirements § 135.203 VFR: Minimum altitudes. Except when necessary for... above the surface or less than 500 feet horizontally from any obstacle; or (2) At night, at an...

  7. 14 CFR 91.119 - Minimum safe altitudes: General.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Minimum safe altitudes: General. 91.119... § 91.119 Minimum safe altitudes: General. Except when necessary for takeoff or landing, no person may... fails, an emergency landing without undue hazard to persons or property on the surface. (b)...

  8. Photocopy of drawing, RIGHT ALTITUDE CHAMBER REACTIVATION. NASA, John F. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of drawing, RIGHT ALTITUDE CHAMBER REACTIVATION. NASA, John F. Kennedy Space Center, Florida. Drawing 82K06032, Boeing, December, 1997. ACCESS PLATFORM INSTALLATION. Sheet S2 - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

  9. Photocopy of drawing. RIGHT ALTITUDE CHAMBER REACTIVATION. NASA, John F. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of drawing. RIGHT ALTITUDE CHAMBER REACTIVATION. NASA, John F. Kennedy Space Center, Florida. Drawing 82K06032, Boeing, December, 1997. 15 FT LEVEL EQUIPMENT LAYOUT. Sheet E13 - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

  10. Photocopy of drawing. RIGHT ALTITUDE CHAMBER REACTIVATION. NASA, John F. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of drawing. RIGHT ALTITUDE CHAMBER REACTIVATION. NASA, John F. Kennedy Space Center, Florida. Drawing 82K06032, Boeing, December, 1997. ACCESS PLATFORM DEMOLITION. Sheet S1 - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

  11. 10 CFR 862.6 - Voluntary minimum altitude.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Voluntary minimum altitude. 862.6 Section 862.6 Energy DEPARTMENT OF ENERGY RESTRICTIONS ON AIRCRAFT LANDING AND AIR DELIVERY AT DEPARTMENT OF ENERGY NUCLEAR SITES § 862.6 Voluntary minimum altitude. In addition to complying with all applicable FAA prohibitions...

  12. Quadrant to Measure the Sun's Altitude

    ERIC Educational Resources Information Center

    Windsor, A Morgan, Jr.

    2013-01-01

    The changing altitude of the Sun (either over the course of a day or longer periods) is a phenomenon that students do not normally appreciate. However, the altitude of the Sun affects many topics in disciplines as diverse as astronomy, meteorology, navigation, or horology, such as the basis for seasons, determination of latitude and longitude, or…

  13. Comparative aspects of high-altitude adaptation in human populations.

    PubMed

    Moore, L G; Armaza, F; Villena, M; Vargas, E

    2000-01-01

    The conditions and duration of high-altitude residence differ among high-altitude populations. The Tibetan Plateau is larger, more geographically remote, and appears to have been occupied for a longer period of time than the Andean Altiplano and, certainly, the Rocky Mountain region as judged by archaeological, linguistic, genetic and historical data. In addition, the Tibetan gene pool is less likely to have been constricted by small numbers of initial migrants and/or severe population decline, and to have been less subject to genetic admixture with lowland groups. Comparing Tibetans to other high-altitude residents demonstrates that Tibetans have less intrauterine growth retardation better neonatal oxygenation higher ventilation and hypoxic ventilatory response lower pulmonary arterial pressure and resistance lower hemoglobin concentrations and less susceptibility to CMS These findings are consistent with the conclusion that "adaptation" to high altitude increases with time, considering time in generations of high-altitude exposure. Future research is needed to compare the extent of IUGR and neonatal oxygenation in South American high-altitude residents of Andean vs. European ancestry, controlling for gestational age and other characteristics. Another fruitful line of inquiry is likely to be determining whether persons with CMS or other altitude-associated problems experienced exaggerated hypoxia during prenatal or neonatal life. Finally, the comparison of high-altitude populations with respect to the frequencies of genes involved in oxygen sensing and physiologic response to hypoxia will be useful, once candidate genes have been identified. PMID:10849648

  14. Altitude acclimatization. Citations from the International Aerospace Abstracts data base

    NASA Technical Reports Server (NTRS)

    Mauk, S. C.

    1980-01-01

    This bibliography of citations to the international literature covers aspects of altitude acclimatization. Included are articles concerning high altitude environments, hypoxia, heart function and hemodynamic responses, physical exercise, human tolerances and reactions, physiological responses, and oxygen consumption. This updated bibliography contains 164 citations, 35 of which are new entries to the previous edition.

  15. 14 CFR 121.661 - Initial approach altitude: Flag operations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Initial approach altitude: Flag operations... OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Dispatching and Flight Release Rules § 121.661 Initial approach altitude: Flag operations. When making an initial approach to a...

  16. 14 CFR 121.661 - Initial approach altitude: Flag operations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Initial approach altitude: Flag operations... OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Dispatching and Flight Release Rules § 121.661 Initial approach altitude: Flag operations. When making an initial approach to a...

  17. 14 CFR 121.661 - Initial approach altitude: Flag operations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Initial approach altitude: Flag operations... OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Dispatching and Flight Release Rules § 121.661 Initial approach altitude: Flag operations. When making an initial approach to a...

  18. 14 CFR 121.661 - Initial approach altitude: Flag operations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Initial approach altitude: Flag operations... OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Dispatching and Flight Release Rules § 121.661 Initial approach altitude: Flag operations. When making an initial approach to a...

  19. 14 CFR 121.661 - Initial approach altitude: Flag operations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Initial approach altitude: Flag operations... OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Dispatching and Flight Release Rules § 121.661 Initial approach altitude: Flag operations. When making an initial approach to a...

  20. Biventricular thrombosis in a structurally normal heart at high altitude

    PubMed Central

    Malani, Susheel; Chadha, Davinder; Banerji, Anup

    2014-01-01

    We present a rare case of biventricular thrombus in a young patient with a structurally normal heart at high altitude, complicated with pulmonary embolism. Detailed evaluation revealed him to have protein S deficiency. Altered environmental conditions at high altitude associated with protein S deficiency resulted in thrombus formation at an unusual location; the same is discussed in this case report. PMID:24879736

  1. 14 CFR 91.515 - Flight altitude rules.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Flight altitude rules. 91.515 Section 91...) AIR TRAFFIC AND GENERAL OPERATING RULES GENERAL OPERATING AND FLIGHT RULES Large and Turbine-Powered Multiengine Airplanes and Fractional Ownership Program Aircraft § 91.515 Flight altitude rules....

  2. Spirometry and respiratory muscle function during ascent to higher altitudes.

    PubMed

    Sharma, Sat; Brown, Bryce

    2007-01-01

    Alteration in lung function at high altitude influences exercise capacity, worsens hypoxia, and may predispose to high-altitude illness. The effect of high altitude on lung function and mechanisms responsible for these alterations remain unclear. Seven adult male mountaineers were followed prospectively during a climbing expedition to Mount Everest, Nepal. Measurements of spirometry and respiratory muscle function were performed for the duration of the expedition, during changes in altitude between 3450 and 7200 meters (m). Measurements included the forced vital capacity (FVC), forced expiratory volume in 1 second (FEV(1)), maximal voluntary ventilation (MVV) in 12 seconds, maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and respiratory muscle endurance (Tlim). At an altitude of 3450 m, the FVC initially increased (9%) over 24 h, followed by a significant decline; the FEV(1), MVV, MIP, and MEP showed similar progressive decline. At 5350 m, FVC increased by 21% over the first 48 h, then decreased. The FVC, FEV(1), MVV, MIP, and MEP initially increased and then gradually diminished over time. Respiratory muscle endurance (Tlim) decreased over the first three days at 3450 m but then remained unchanged. MVV decreased at lower altitude followed by a slight increase and then a significant decline. Compared with baseline, we observed a fluctuating course for spirometric measurements, respiratory muscle strength, and endurance at high altitude. Initial transient increases in parameters occurred on ascent to each new altitude followed by a gradual decline during prolonged stay. PMID:17393241

  3. Users guide to high altitude imagery of Michigan

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A guide to the high altitude imagery of Michigan outlines the areas of the state covered by selected recent high altitude aircraft and Earth Resources Technology Satellite flights. The types of remote sensing used are described. Maps of the flight coverage areas are included along with price lists of available imagery.

  4. Introductory address: lessons to be learned from high altitude.

    PubMed Central

    Houston, C. S.

    1979-01-01

    A historical account of the important landmarks in man's experience with the high altitude environment is followed by comments on the important stages in the understanding of its physiological effects. The work of The Mount Logan High Altitude Physiology Study on acute mountain sickness is reviewed from its inception in 1967 until the present. PMID:386292

  5. 14 CFR 91.177 - Minimum altitudes for IFR operations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... pilot operating the aircraft of that distance); or (2) If no applicable minimum altitude is prescribed... mountainous area in part 95 of this chapter, an altitude of 2,000 feet above the highest obstacle within a horizontal distance of 4 nautical miles from the course to be flown; or (ii) In any other case, an...

  6. 14 CFR 135.203 - VFR: Minimum altitudes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false VFR: Minimum altitudes. 135.203 Section 135.203 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED... Operating Limitations and Weather Requirements § 135.203 VFR: Minimum altitudes. Except when necessary...

  7. Perspectives on functional adaptation of the high altitude native.

    PubMed

    Frisancho, A R

    1983-01-01

    The major physiological processes that enable humans to attain a complete acclimatization to high altitude are briefly reviewed. The available data indicate that: (a) complete acclimatization to high altitude is associated with changes of environmentally modifiable functional traits such as lung volume but not associated with the expression of genetically controlled features such as chest size; (b) as judged by measurements of maximal aerobic power, the high altitude native has attained at high altitude an adaptation that is comparable to that attained by the low altitude native at sea level; the available information suggests that such adaptation is acquired through growth and development in an hypoxic environment; at present, however, we do not know the developmental modifications that occur within each component of the oxygen transport system, such as ventilation, pulmonary diffusion, and oxygen transport, that enable a sea level native to attain a complete functional adaptation to high altitude; and (c) at comparable altitudes among high altitude natives, there are some inter-regional differences in hemopoietic response, so that the samples derived from mining regions of the Andes are characterized by higher hemoglobin concentration than those derived from non-mining areas or the Himalayas. The source of these differences remains to be investigated. PMID:6364176

  8. Visual-Motion Cueing in Altitude and Yaw Control

    NASA Technical Reports Server (NTRS)

    Johnson, Walter W.; Schroeder, Jeffery; Statler, Irving C. (Technical Monitor)

    1994-01-01

    Research conducted using the Vertical Motion Simulator at the NASA Ames Research Center examined the contributions of platform motion and visual level-of-detail (LOD) cueing to tasks that required altitude and/or yaw control in a simulated AH-64 Apache helicopter. Within the altitude control tasks the LOD manipulation caused optical density to change across altitudes by a small, moderate, or large amount; while platform motion was either present or absent. The results from these tasks showed that both constant optical density and platform motion improved altitude awareness in an altitude repositioning task, while the presence of platform motion also led to improved performance in a vertical rate control task. The yaw control tasks had pilots'sit 4.5 ft in front of the center of rotation, thus subjecting them to both rotational and lateral motions during a yaw. The pilots were required to regulate their yaw, while the platform motion was manipulated in order to present all combinations of the resulting rotational and lateral motion components. Ratings of simulation fidelity and sensed platform motion showed that the pilots were relatively insensitive to the rotational component, but highly aware of the lateral component. Together these findings show that: 1) platform motion cues are important when speed regulation is required during altitude change; 2) platform motion contributes to the perception of movement amplitude; 3) lateral, but not rotational, motion cues are essential to the perception of vehicle yaw; and 4) LOD management yielding constant optical density across altitudes improves altitude awareness.

  9. AltitudeOmics: Resetting of Cerebrovascular CO2 Reactivity Following Acclimatization to High Altitude

    PubMed Central

    Fan, Jui-Lin; Subudhi, Andrew W.; Duffin, James; Lovering, Andrew T.; Roach, Robert C.; Kayser, Bengt

    2016-01-01

    Previous studies reported enhanced cerebrovascular CO2 reactivity upon ascent to high altitude using linear models. However, there is evidence that this response may be sigmoidal in nature. Moreover, it was speculated that these changes at high altitude are mediated by alterations in acid-base buffering. Accordingly, we reanalyzed previously published data to assess middle cerebral blood flow velocity (MCAv) responses to modified rebreathing at sea level (SL), upon ascent (ALT1) and following 16 days of acclimatization (ALT16) to 5260 m in 21 lowlanders. Using sigmoid curve fitting of the MCAv responses to CO2, we found the amplitude (95 vs. 129%, SL vs. ALT1, 95% confidence intervals (CI) [77, 112], [111, 145], respectively, P = 0.024) and the slope of the sigmoid response (4.5 vs. 7.5%/mmHg, SL vs. ALT1, 95% CIs [3.1, 5.9], [6.0, 9.0], respectively, P = 0.026) to be enhanced at ALT1, which persisted with acclimatization at ALT16 (amplitude: 177, 95% CI [139, 215], P < 0.001; slope: 10.3%/mmHg, 95% CI [8.2, 12.5], P = 0.003) compared to SL. Meanwhile, the sigmoidal response midpoint was unchanged at ALT1 (SL: 36.5 mmHg; ALT1: 35.4 mmHg, 95% CIs [34.0, 39.0], [33.1, 37.7], respectively, P = 0.982), while it was reduced by ~7 mmHg at ALT16 (28.6 mmHg, 95% CI [26.4, 30.8], P = 0.001 vs. SL), indicating leftward shift of the cerebrovascular CO2 response to a lower arterial partial pressure of CO2 (PaCO2) following acclimatization to altitude. Sigmoid fitting revealed a leftward shift in the midpoint of the cerebrovascular response curve which could not be observed with linear fitting. These findings demonstrate that there is resetting of the cerebrovascular CO2 reactivity operating point to a lower PaCO2 following acclimatization to high altitude. This cerebrovascular resetting is likely the result of an altered acid-base buffer status resulting from prolonged exposure to the severe hypocapnia associated with ventilatory acclimatization to high altitude. PMID:26779030

  10. Access 5 - Step 1: Human Systems Integration Program Plan (HSIPP)

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This report describes the Human System Interface (HSI) analysis, design and test activities that will be performed to support the development of requirements and design guidelines to facilitate the incorporation of High Altitude Long Endurance (HALE) Remotely Operated Aircraft (ROA) at or above FL400 in the National Airspace System (NAS). These activities are required to support the design and development of safe, effective and reliable ROA operator and ATC interfaces. This plan focuses on the activities to be completed for Step 1 of the ACCESS 5 program. Updates to this document will be made for each of the four ACCESS 5 program steps.

  11. Microgravity combustion experiment using high altitude balloon.

    NASA Astrophysics Data System (ADS)

    Kan, Yuji

    In JAXA, microgravity experiment system using a high altitude balloon was developed , for good microgravity environment and short turn-around time. In this publication, I give an account of themicrogravity experiment system and a combustion experiment to utilize the system. The balloon operated vehicle (BOV) as a microgravity experiment system was developed from 2004 to 2009. Features of the BOV are (1) BOV has double capsule structure. Outside-capsule and inside-capsule are kept the non-contact state by 3-axis drag-free control. (2) The payload is spherical shape and itsdiameter is about 300 mm. (3) Keep 10-4 G level microgravity environment for about 30 seconds However, BOV’s payload was small, and could not mount large experiment module. In this study, inherits the results of past, we established a new experimental system called “iBOV” in order toaccommodate larger payload. Features of the iBOV are (1) Drag-free control use for only vertical direction. (2) The payload is a cylindrical shape and its size is about 300 mm in diameter and 700 mm in height. (3) Keep 10-3-10-4 G level microgravity environment for about 30 seconds We have "Observation experiment of flame propagation behavior of the droplets column" as experiment using iBOV. This experiment is a theme that was selected first for technical demonstration of iBOV. We are conducting the flame propagation mechanism elucidation study of fuel droplets array was placed at regular intervals. We conducted a microgravity experiments using TEXUS rocket ESA and drop tower. For this microgravity combustion experiment using high altitude balloon, we use the Engineering Model (EM) for TEXUS rocket experiment. The EM (This payload) consists of combustion vessel, droplets supporter, droplets generator, fuel syringe, igniter, digital camera, high-speed camera. And, This payload was improved from the EM as follows. (1) Add a control unit. (2) Add inside batteries for control unit and heater of combustion

  12. Understanding controls on cirque floor altitudes: Insights from Kamchatka

    NASA Astrophysics Data System (ADS)

    Barr, Iestyn D.; Spagnolo, Matteo

    2015-11-01

    Glacial cirques reflect former regions of glacier initiation, and are therefore used as indicators of past climate. One specific way in which palaeoclimatic information is obtained from cirques is by analysing their elevations, on the assumption that cirque floor altitudes are a proxy for climatically controlled equilibrium-line altitudes (ELAs) during former periods of small scale (cirque-type) glaciation. However, specific controls on cirque altitudes are rarely assessed, and the validity of using cirque floor altitudes as a source of palaeoclimatic information remains open to question. In order to address this, here we analyse the distribution of 3520 ice-free cirques on the Kamchatka Peninsula (eastern Russia), and assess various controls on their floor altitudes. In addition, we analyse controls on the mid-altitudes of 503 modern glaciers, currently identifiable on the peninsula, and make comparisons with the cirque altitude data. The main study findings are that cirque floor altitudes increase steeply inland from the Pacific, suggesting that moisture availability (i.e., proximity to the coastline) played a key role in regulating the altitudes at which former (cirque-forming) glaciers were able to initiate. Other factors, such as latitude, aspect, topography, geology, and neo-tectonics seem to have played a limited (but not insignificant) role in regulating cirque floor altitudes, though south-facing cirques are typically higher than their north-facing equivalents, potentially reflecting the impact of prevailing wind directions (from the SSE) and/or variations in solar radiation on the altitudes at which former glaciers were able to initiate. Trends in glacier and cirque altitudes across the peninsula are typically comparable (i.e., values typically rise from both the north and south, inland from the Pacific coastline, and where glaciers/cirques are south-facing), yet the relationship with latitude is stronger for modern glaciers, and the relationship with

  13. Practical immunochemical method for determination of 3,5, 6-trichloro-2-pyridinol in human urine: applications and considerations for exposure assessment.

    PubMed

    Shackelford, D D; Young, D L; Mihaliak, C A; Shurdut, B A; Itak, J A

    1999-01-01

    An analytical method is described for the quantitative determination of 3,5,6-trichloro-2-pyridinol (3,5,6-TCP) in human urine. This is the primary analyte found in urine as a result of exposure to chlorpyrifos, chlorpyrifos-methyl, triclopyr, or 3,5,6-TCP. Conjugates of 3,5,6-TCP are released from urine by acid hydrolysis. The free 3,5,6-TCP is purified using C(18) solid-phase extraction, eluting the analyte with 1-chlorobutane. An aliquot of 1-chlorobutane is placed in a vial containing Trichloropyridinol Sample Diluent and evaporated, leaving the 3,5,6-TCP in the aqueous sample diluent. The samples are assayed using the Trichloropyridinol RaPID Assay immunoassay test kit. Final results are calculated using a standard curve constructed by linear regression after a ln/Logit data transformation is performed of the concentration and the absorbance readings, respectively. The calculated lower limit of quantitation for 3,5,6-TCP in fortified control urine samples is 2. 96 ng/mL (2.96 ppb). Residues of 3,5,6-TCP determined using both immunochemical and gas chromatography with mass spectrometric detection correlate well. PMID:10563869

  14. COMPARISON OF IMMUNOASSAY AND GAS CHROMATOGRAPHY/MASS SPECTROMETRY METHODS FOR MEASURING 3,5,6-TRICHLORO-2PYRIDINOL IN MULTIPLE SAMPLE MEDIA

    EPA Science Inventory

    Two enzyme-linked immunosorbent assay (ELISA) methods were evaluated for the determination of 3,5,6-trichloro-2-pyridinol (3,5,6-TCP) in multiple sample media (dust, soil, food, and urine). The dust and soil samples were analyzed by a commercial RaPID immunoassay testing kit. ...

  15. Dynamic response at altitude of a turbojet engine with variable area exhaust nozzle

    NASA Technical Reports Server (NTRS)

    Delio, Gene J; Rosenweig, Solomon

    1952-01-01

    The dynamic characteristics of turbojet engine with variable exhaust nozzle area were investigated over a range of altitudes and flight Mach numbers. These characteristics generalize to standard static level condition. Data resulting from approximate step disturbances in either manipulated variable suggested functional relationships from which functions can be derived. The constants of the transfer functions are listed for five combinations of engine speed and exhaust nozzle area. The minimum data needed to completely define the transfer functions were: experimentally determined dynamic characteristics, such as engine time constant and initial rise ratio, resulting from either manipulated variable; static characteristics determined from steady-state performance curves.

  16. Free and total thyroid hormones in humans at extreme altitude

    NASA Astrophysics Data System (ADS)

    Basu, Minakshi; Pal, K.; Malhotra, A. S.; Prasad, R.; Sawhney, R. C.

    1995-03-01

    Alterations in circulatory levels of total T4 (TT4), total T3 (TT3), free T4 (FT4), free T3 (FT3), thyrotropin (TSH) and T3 uptake (T3U) were studied in male and female sea-level residents (SLR) at sea level, in Armed forces personnel staying at high altitude (3750 m) for prolonged duration (acclimatized lowlanders, ALL) and in high-altitude natives (HAN). Identical studies were also performed on male ALL who trekked to an extreme altitude of 5080 m and stayed at an altitude of more than 6300 m for about 6 months. The total as well as free thyroid hormones were found to be significantly higher in ALL and HAN as compared to SLR values. Both male as well as female HAN had higher levels of thyroid hormones. The rise in hormone levels in different ALL ethnic groups drawn from amongst the southern and northern parts of the country was more or less identical. In both HAN and ALL a decline in FT3 and FT4 occurred when these subjects trekked at subzero temperatures to extreme altitude of 5080 m but the levels were found to be higher in ALL who stayed at 6300 m for a prolonged duration. Plasma TSH did not show any appreciable change at lower altitudes but was found to be decreased at extreme altitude. The increase in thyroid hormones at high altitude was not due to an increase in hormone binding proteins, since T3U was found to be higher at high altitudes. A decline in TSH and hormone binding proteins and an increase in the free moiety of the hormones is indicative of a subtle degree of tissue hyperthyroidism which may be playing an important role in combating the extreme cold and hypoxic environment of high altitudes.

  17. Increased oxidative stress following acute and chronic high altitude exposure.

    PubMed

    Jefferson, J Ashley; Simoni, Jan; Escudero, Elizabeth; Hurtado, Maria-Elena; Swenson, Erik R; Wesson, Donald E; Schreiner, George F; Schoene, Robert B; Johnson, Richard J; Hurtado, Abdias

    2004-01-01

    The generation of reactive oxygen species is typically associated with hyperoxia and ischemia reperfusion. Recent evidence has suggested that increased oxidative stress may occur with hypoxia. We hypothesized that oxidative stress would be increased in subjects exposed to high altitude hypoxia. We studied 28 control subjects living in Lima, Peru (sea level), at baseline and following 48 h exposure to high altitude (4300 m). To assess the effects of chronic altitude exposure, we studied 25 adult males resident in Cerro de Pasco, Peru (altitude 4300 m). We also studied 27 subjects living in Cerro de Pasco who develop excessive erythrocytosis (hematocrit > 65%) and chronic mountain sickness. Acute high altitude exposure led to increased urinary F(2)-isoprostane, 8-iso PGF(2 alpha) (1.31 +/- 0.8 microg/g creatinine versus 2.15 +/- 1.1, p = 0.001) and plasma total glutathione (1.29 +/- 0.10 micromol versus 1.37 +/- 0.09, p = 0.002), with a trend to increased plasma thiobarbituric acid reactive substance (TBARS) (59.7 +/- 36 pmol/mg protein versus 63.8 +/- 27, p = NS). High altitude residents had significantly elevated levels of urinary 8-iso PGF(2 alpha) (1.3 +/- 0.8 microg/g creatinine versus 4.1 +/- 3.4, p = 0.007), plasma TBARS (59.7 +/- 36 pmol/mg protein versus 85 +/- 28, p = 0.008), and plasma total glutathione (1.29 +/- 0.10 micromol versus 1.55 +/- 0.19, p < 0.0001) compared to sea level. High altitude residents with excessive erythrocytosis had higher levels of oxidative stress compared to high altitude residents with normal hematological adaptation. In conclusion, oxidative stress is increased following both acute exposure to high altitude without exercise and with chronic residence at high altitude. PMID:15072717

  18. Impact of Altitude on Power Output during Cycling Stage Racing

    PubMed Central

    Garvican-Lewis, Laura A; Clark, Bradley; Martin, David T.; Schumacher, Yorck Olaf; McDonald, Warren; Stephens, Brian; Ma, Fuhai; Thompson, Kevin G.; Gore, Christopher J.; Menaspà, Paolo

    2015-01-01

    Purpose The purpose of this study was to quantify the effects of moderate-high altitude on power output, cadence, speed and heart rate during a multi-day cycling tour. Methods Power output, heart rate, speed and cadence were collected from elite male road cyclists during maximal efforts of 5, 15, 30, 60, 240 and 600 s. The efforts were completed in a laboratory power-profile assessment, and spontaneously during a cycling race simulation near sea-level and an international cycling race at moderate-high altitude. Matched data from the laboratory power-profile and the highest maximal mean power output (MMP) and corresponding speed and heart rate recorded during the cycling race simulation and cycling race at moderate-high altitude were compared using paired t-tests. Additionally, all MMP and corresponding speeds and heart rates were binned per 1000m (<1000m, 1000–2000, 2000–3000 and >3000m) according to the average altitude of each ride. Mixed linear modelling was used to compare cycling performance data from each altitude bin. Results Power output was similar between the laboratory power-profile and the race simulation, however MMPs for 5–600 s and 15, 60, 240 and 600 s were lower (p ≤ 0.005) during the race at altitude compared with the laboratory power-profile and race simulation, respectively. Furthermore, peak power output and all MMPs were lower (≥ 11.7%, p ≤ 0.001) while racing >3000 m compared with rides completed near sea-level. However, speed associated with MMP 60 and 240 s was greater (p < 0.001) during racing at moderate-high altitude compared with the race simulation near sea-level. Conclusion A reduction in oxygen availability as altitude increases leads to attenuation of cycling power output during competition. Decrement in cycling power output at altitude does not seem to affect speed which tended to be greater at higher altitudes. PMID:26629912

  19. The Next Giant Step

    NASA Video Gallery

    Artist Robert McCall painted "The Next Giant Step" in 1979 to commemorate the heroism and courage of spaceflight pioneers. Located in the lobby of Johnson's building 2, the mural depicts America's ...

  20. High Altitude Observatory YBJ and ARGO Project

    NASA Astrophysics Data System (ADS)

    Tan, Y.; ARGO Collaboration

    A 5800 m2 RPC (Resistive Plate Chamber) full coverage air shower array is under construction in the YangBaJing Cosmic Ray Observatory, Tibet of China, by the ChinaItaly ARGO Collaboration. YBJ is a large flat grassland with an area 10 × 70 km2 at 4300m altitude, about 90 north west from Lhasa. Its nearby power station, asphalt road to Lhasa, passing railway (will be constructed during the coming 5 years), optical fiber link to the INTERNET, rare snow and other favourable weather conditions are well suitable for setting an Astrophysical Observatory here. The installation of a large area carpet-like detector in this peculiar site will allow one to perform an all-sky and high duty cycle study of high energy gamma rays from 100GeV to 50 TeV as well as accurate measurements on UHE cosmic rays. To insure the stable and uniform working condition of RPCs, a 104 M2 carpet hall was constructed, the RPC installation have be started in it since last November. The natural distribution and daily variation of temperature in the hall, the data concerning the performances of the installed RPCs, have been measured, the results are presented. ce

  1. NASA/USRA high altitude reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Richardson, Michael; Gudino, Juan; Chen, Kenny; Luong, Tai; Wilkerson, Dave; Keyvani, Anoosh

    1990-01-01

    At the equator, the ozone layer ranges from approximately 80,000 to 130,000+ feet which is beyond the capabilities of the ER-2, NASA's current high altitude reconnaissance aircraft. This project is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to cruise at 130,000 lbs. of payload. In addition, the aircraft must have a minimum of a 6,000 mile range. The low Mach number, payload, and long cruising time are all constraints imposed by the air sampling equipment. A pilot must be able to take control in the event of unforseen difficulties. Three aircraft configurations were determined to be the most suitable for meeting the above requirements, a joined-wing, a bi-plane, and a twin-boom conventional airplane. The techniques used have been deemed reasonable within the limits of 1990 technology. The performance of each configuration is analyzed to investigate the feasibility of the project requirements. In the event that a requirement can not be obtained within the given constraints, recommendations for proposal modifications are given.

  2. The High Altitude Water Cherenkov (HAWC) Observatory

    NASA Astrophysics Data System (ADS)

    Springer, Wayne

    2014-06-01

    The High Altitude Water Cherenkov (HAWC) observatory is a continuously operated, wide field of view detector based upon a water Cherenkov technology developed by the Milagro experiment. HAWC observes, at an elevation of 4100 m on Sierra Negra Mountain in Mexico, extensive air showers initiated by gamma and cosmic rays. The completed detector will consist of 300 closely spaced water tanks each instrumented with four photomultiplier tubes that provide timing and charge information used to reconstruct energy and arrival direction. HAWC has been optimized to observe transient and steady emission from point as well as diffuse sources of gamma rays in the energy range from several hundred GeV to several hundred TeV. Studies in solar physics as well as the properties of cosmic rays will also be performed. HAWC has been making observations at various stages of deployment since completion of 10% of the array in summer 2012. A discussion of the detector design, science capabilities, current construction/commissioning status, and first results will be presented...

  3. SHARP: Subsonic High Altitude Research Platform

    NASA Technical Reports Server (NTRS)

    Beals, Todd; Burton, Craig; Cabatan, Aileen; Hermano, Christine; Jones, Tom; Lee, Susan; Radloff, Brian

    1991-01-01

    The Universities Space Research Association is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to satisfy four mission profiles. Mission one is a polar mission that ranges from Chile to the South Pole and back to Chile, a total range of 6000 n.mi. at 100,000 ft with a 2500 lb payload. The second mission is also a polar mission, with an altitude of 70,000 ft and an increased payload of 4000 lbs. For the third mission, the aircraft will takeoff at NASA Ames, cruise at 100,000 ft carrying a 2500 lb payload, and land at Puerto Montt, Chile. The final mission requires the aircraft to take off at NASA Ames, cruise at 100,000 ft with a 1000 lb payload, make an excursion to 120,000 ft, and land at Howard AFB, Panama. Three missions require that a subsonic Mach number be maintained due to constraints imposed by the air sampling equipment. The aircraft need not be manned for all four missions. Three aircraft configurations have been determined to be the most suitable for meeting the above requirements. In the event that a requirement cannot be obtained within the given constraints, recommendations for proposal modifications are given.

  4. The High-Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    Mostafá, Miguel A.

    2014-10-01

    The High-Altitude Water Cherenkov (HAWC) observatory is a large field of view, continuously operated, TeV γ-ray experiment under construction at 4,100 m a.s.l. in Mexico. The HAWC observatory will have an order of magnitude better sensitivity, angular resolution, and background rejection than its predecessor, the Milagro experiment. The improved performance will allow us to detect both the transient and steady emissions, to study the Galactic diffuse emission at TeV energies, and to measure or constrain the TeV spectra of GeV γ-ray sources. In addition, HAWC will be the only ground-based instrument capable of detecting prompt emission from γ-ray bursts above 50 GeV. The HAWC observatory will consist of an array of 300 water Cherenkov detectors (WCDs), each with four photomultiplier tubes. This array is currently under construction on the flanks of the Sierra Negra volcano near the city of Puebla, Mexico. The first 30 WCDs (forming an array approximately the size of Milagro) were deployed in Summer 2012, and 100 WCDs will be taking data by May, 2013. We present in this paper the motivation for constructing the HAWC observatory, the status of the deployment, and the first results from the constantly growing array.

  5. Effects of High Altitude on Sleep and Respiratory System and Theirs Adaptations

    PubMed Central

    San, Turhan; Polat, Senol; Cingi, Cemal; Eskiizmir, Gorkem; Oghan, Fatih; Cakir, Burak

    2013-01-01

    High-altitude (HA) environments have adverse effects on the normal functioning body of people accustomed to living at low altitudes because of the change in barometric pressure which causes decrease in the amount of oxygen leading to hypobaric hypoxia. Sustained exposure to hypoxia has adverse effects on body weight, muscle structure and exercise capacity, mental functioning, and sleep quality. The most important step of acclimatization is the hyperventilation which is achieved by hypoxic ventilatory response of the peripheral chemoreceptors. Hyperventilation results in increase in arterial carbondioxide concentration. Altitude also affects sleep and cardiac output, which is the other determinant of oxygen delivery. Upon initial exposure to HA, the resting pulse rate increases rapidly, but with acclimatization, heart rate and cardiac output tend to fall. Another important component that leads to decrease in cardiac output is the reduction in the stroke volume with acclimatization. During sleep at HA, the levels of CO2 in the blood can drop very low and this can switch off the drive to breathe. Only after the body senses a further drop in O2 levels breathing is started again. Periodic breathing is thought to result from instability in the control system through the hypoxic drive or the response to CO2. PMID:23690739

  6. Altitude Effects on Thermal Ice Protection System Performance; a Study of an Alternative Approach

    NASA Technical Reports Server (NTRS)

    Addy, Harold E., Jr.; Orchard, David; Wright, William B.; Oleskiw, Myron

    2016-01-01

    Research has been conducted to better understand the phenomena involved during operation of an aircraft's thermal ice protection system under running wet icing conditions. In such situations, supercooled water striking a thermally ice-protected surface does not fully evaporate but runs aft to a location where it freezes. The effects of altitude, in terms of air pressure and density, on the processes involved were of particular interest. Initial study results showed that the altitude effects on heat energy transfer were accurately modeled using existing methods, but water mass transport was not. Based upon those results, a new method to account for altitude effects on thermal ice protection system operation was proposed. The method employs a two-step process where heat energy and mass transport are sequentially matched, linked by matched surface temperatures. While not providing exact matching of heat and mass transport to reference conditions, the method produces a better simulation than other methods. Moreover, it does not rely on the application of empirical correction factors, but instead relies on the straightforward application of the primary physics involved. This report describes the method, shows results of testing the method, and discusses its limitations.

  7. Effects of high altitude on sleep and respiratory system and theirs adaptations.

    PubMed

    San, Turhan; Polat, Senol; Cingi, Cemal; Eskiizmir, Gorkem; Oghan, Fatih; Cakir, Burak

    2013-01-01

    High-altitude (HA) environments have adverse effects on the normal functioning body of people accustomed to living at low altitudes because of the change in barometric pressure which causes decrease in the amount of oxygen leading to hypobaric hypoxia. Sustained exposure to hypoxia has adverse effects on body weight, muscle structure and exercise capacity, mental functioning, and sleep quality. The most important step of acclimatization is the hyperventilation which is achieved by hypoxic ventilatory response of the peripheral chemoreceptors. Hyperventilation results in increase in arterial carbon-dioxide concentration. Altitude also affects sleep and cardiac output, which is the other determinant of oxygen delivery. Upon initial exposure to HA, the resting pulse rate increases rapidly, but with acclimatization, heart rate and cardiac output tend to fall. Another important component that leads to decrease in cardiac output is the reduction in the stroke volume with acclimatization. During sleep at HA, the levels of CO2 in the blood can drop very low and this can switch off the drive to breathe. Only after the body senses a further drop in O2 levels breathing is started again. Periodic breathing is thought to result from instability in the control system through the hypoxic drive or the response to CO2. PMID:23690739

  8. Novel Gene Clusters and Metabolic Pathway Involved in 3,5,6-Trichloro-2-Pyridinol Degradation by Ralstonia sp. Strain T6

    PubMed Central

    Li, Jingquan; Huang, Yan; Hou, Ying; Li, Xiangmin; Cao, Hui

    2013-01-01

    3,5,6-Trichloro-2-pyridinol (TCP) is a widespread pollutant. Some bacteria and fungi have been reported to degrade TCP, but the gene clusters responsible for TCP biodegradation have not been characterized. In this study, a fragment of the reduced flavin adenine dinucleotide (FADH2)-dependent monooxygenase gene tcpA was amplified from the genomic DNA of Ralstonia sp. strain T6 with degenerate primers. The tcpA disruption mutant strain T6-ΔtcpA could not degrade TCP but could degrade the green intermediate metabolite 3,6-dihydroxypyridine-2,5-dione (DHPD), which was generated during TCP biodegradation by strain T6. The flanking sequences of tcpA were obtained by self-formed adaptor PCR. tcpRXA genes constitute a gene cluster. TcpR and TcpX are closely related to the LysR family transcriptional regulator and flavin reductase, respectively. T6-ΔtcpA-com, the complementation strain for the mutant strain T6-ΔtcpA, recovered the ability to degrade TCP, and the strain Escherichia coli DH10B-tcpRXA, which expressed the tcpRXA gene cluster, had the ability to transform TCP to DHPD, indicating that tcpA is a key gene in the initial step of TCP degradation and that TcpA dechlorinates TCP to DHPD. A library of DHPD degradation-deficient mutants of strain T6 was obtained by random transposon mutagenesis. The fragments flanking the Mariner transposon were amplified and sequenced, and the dhpRIJK gene cluster was cloned. DhpJ could transform DHPD to yield an intermediate product, 5-amino-2,4,5-trioxopentanoic acid (ATOPA), which was further degraded by DhpI. DhpR and DhpK are closely related to the AraC family transcriptional regulator and the MFS family transporter, respectively. PMID:24056464

  9. Two different deglaciation processes in the subtropical Pacific at MIS 5/6 and 1/2

    NASA Astrophysics Data System (ADS)

    Ujiie, Y.; Asahi, H.

    2011-12-01

    Deglaciation process is one of the results that the tropical climate forcing impact on the global changes by its large heat capacity. However, the deglacial fluctuation has poorly been explored in the tropical Pacific area due to less resolution records from the marine deposits. The Okinawa region is available to represent the high-resolution paleocenographic records of the tropical-subtropical Pacific during the late Quaternary, because of the oscillation between the Kuroshio Current continuing from the North Equatorial Current and central water of the subtropical gyre in this region. Two IMAGES cores were collected from the Okinawa Trough (under the Kuroshio Current) and Ryukyu Trench (under the central water of the subtropical gyre), respectively. Both cores MD982196 (Okinawa Trough) and MD012398 (Ryukyu Trench) covered over the records until Marine Isotope Stage (MIS) 7. Here, we aim to demonstrate the deglacial fluctuations of the surface and intermediate waters during two glacial-interglacial shifts, MIS 6 to 5 and MIS 2 to 1, based on the comprehensive analyses of the oxygen isotopes, Mg/Ca ratios of two planktic foraminiferal faunas (surface and upper intermediate species), and faunal assemblages of planktic foraminifera. The glacial-interglacial cycles were clearly confirmed in whole of the Okinawa region by the planktic δ18O curves. Surface Mg/Ca paleo-temperature showed a same trend as the δ18O curve. However, the paleo-temperature of the upper intermediate water showed unique fluctuation: temperature increased from late MIS 6 to 5e, whereas decreased from MIS 2 to Holocene. Moreover, the temperature difference (dT) between the surface and intermediate layers defined these phenomena. Fast warming of intermediate layer proitor to the deglaciation MIS 5/6 delayed a stratification of water column, while cooling of this layer make a large dT during MIS 1/2. Intriguingly, the faunal compositions of planktic foraminifera changed through the shifts of the

  10. Observations of corona in triggered dart-stepped leaders

    NASA Astrophysics Data System (ADS)

    Gamerota, W. R.; Uman, M. A.; Hill, J. D.; Jordan, D. M.

    2015-03-01

    Corona streamers are a critical component of lightning leader step formation and are postulated to produce the very high electric fields at their tips that produce runaway electrons resulting in the observed X-ray bursts associated with leader stepping. Corona emanating from the vicinity of the leader tip between leader steps was analyzed using three sequential high-speed video sequences of dart-stepped leaders in three different triggered lightning flashes during the summers of 2013 and 2014 in northeast Florida. Images were recorded at 648 kiloframes per second (1.16 µs exposure time, 380 ns dead time) at an altitude of 65 m or less. In each image sequence, the leader propagates downward in consecutive frames, with corona streamers observed to fan outward from the bright leader tip in less than the image frame time of about 1.5 µs. In 21 exposures, corona streamers propagate, on average, 9 m below the bright leader tip.

  11. HIGH LIFE: High altitude fatalities led to pulse oximetry.

    PubMed

    Severinghaus, John W

    2016-01-15

    In 1875, Paul Bert linked high altitude danger to the low partial pressure of oxygen when 2 of 3 French balloonists died euphorically at about 8,600 m altitude. World War I fatal crashes of high altitude fighter pilots led to a century of efforts to use oximetry to warn pilots. The carotid body, discovered in 1932 to be the hypoxia detector, led to most current physiologic understanding of the body's respiratory responses to hypoxia and CO2. The author describes some of his UCSF group's work: In 1963, we reported both the brain's ventral medullary near-surface CO2 (and pH) chemosensors and the role of cerebrospinal fluid in acclimatization to altitude. In 1966, we reported the effect of altitude on cerebral blood flow and later the changes of carotid body sensitivity at altitude and the differences in natives of high altitude. In 1973, pulse oximetry was invented when Japanese biophysicist Takuo Aoyagi read and applied to pulses a largely forgotten 35-year-old discovery by English medical student J. R. Squire of a method of computing oxygen saturation from red and infrared light passing through both perfused and blanched tissue. PMID:26251514

  12. Effects of high altitude and exercise on marksmanship.

    PubMed

    Tharion, W J; Hoyt, R W; Marlowe, B E; Cymerman, A

    1992-02-01

    The effects of exercise and high altitude (3,700 m to 4,300 m) on marksmanship accuracy and sighting time were quantified in 16 experienced marksmen. Subjects dry-fired a disabled rifle equipped with a laser-based system from a free-standing position. The 2.3-cm circular target was at a distance of 5 m. Marksmanship was assessed under the following conditions: 1) at rest at sea level; 2) immediately after a 21-km run/walk ascent from 1,800 m to 4,300 m elevation; 3) at rest during days 1 to 3 at altitude; 4) at rest during days 14 to 16 at altitude; and 5) immediately after a second ascent after 17 d at altitude. Exercise reduced marksmanship accuracy (p less than 0.05) but did not affect sighting time. Acute altitude exposure reduced marksmanship accuracy, and decreased sighting time (p less than 0.05). However, after residence at altitude, accuracy and sighting time at rest returned to sea level values. Exercise and acute altitude exposure had similar but independent detrimental effects on marksmanship. PMID:1546938

  13. DLR HABLEG- High Altitude Balloon Launched Experimental Glider

    NASA Astrophysics Data System (ADS)

    Wlach, S.; Schwarzbauch, M.; Laiacker, M.

    2015-09-01

    The group Flying Robots at the DLR Institute of Robotics and Mechatronics in Oberpfaffenhofen conducts research on solar powered high altitude aircrafts. Due to the high altitude and the almost infinite mission duration, these platforms are also denoted as High Altitude Pseudo-Satellites (HAPS). This paper highlights some aspects of the design, building, integration and testing of a flying experimental platform for high altitudes. This unmanned aircraft, with a wingspan of 3 m and a mass of less than 10 kg, is meant to be launched as a glider from a high altitude balloon in 20 km altitude and shall investigate technologies for future large HAPS platforms. The aerodynamic requirements for high altitude flight included the development of a launch method allowing for a safe transition to horizontal flight from free-fall with low control authority. Due to the harsh environmental conditions in the stratosphere, the integration of electronic components in the airframe is a major effort. For regulatory reasons a reliable and situation dependent flight termination system had to be implemented. In May 2015 a flight campaign was conducted. The mission was a full success demonstrating that stratospheric research flights are feasible with rather small aircrafts.

  14. Gravity Disturbances at Altitude and at the Surface

    NASA Astrophysics Data System (ADS)

    Damiani, T.

    2013-12-01

    The U.S. National Geodetic Survey (NGS) is committed to redefining the nation's vertical datum by 2022. In support of the new vertical datum, NGS is collecting high-altitude airborne gravity data across the United States through the Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project. GRAV-D (as of August 2013) has publicly released full-field gravity products from these high-altitude flights for >15% of the country. The full-field gravity (FFG) at altitude product is versatile because it allows the user to calculate any disturbance or anomaly that is appropriate for their application- based on any datum and height above the datum desired. However, conventional geophysical methods for calculating gravity disturbances assume very low altitudes above the ellipsoid. This presentation addresses the differences between several conventional and non-conventional methods for calculating gravity disturbances, from the perspective of altitudes as high as 40,000 ft. The methods for calculating a disturbance at altitude apply different corrections to the FFG for: 1. Normal gravity at the surface of the ellipsoid and the free-air reduction (1st order, 2nd order, and higher order approximations); 2. Normal gravity at the surface of the ellipsoid, upward continued to flight height; 3. Normal gravity at flight altitude above the ellipsoid from Heiskanen and Moritz (1967)'s closed equations; 4. Normal gravity at flight altitude above the ellipsoid from spherical and ellipsoidal harmonic coefficients of the ellipsoid. Initial results indicate that these methods produce gravity disturbances that are 10s of mGals different at altitude. This presentation will also investigate disturbances calculated at the surface of the ellipsoid, by downward continuing the results of the above methods. Gravity disturbances continued from airborne flight heights down to the surface are desired for comparison to terrestrial and marine gravity data.

  15. The effect of high altitude on nasal nitric oxide levels.

    PubMed

    Altundag, Aytug; Salihoglu, Murat; Cayonu, Melih; Cingi, Cemal; Tekeli, Hakan; Hummel, Thomas

    2014-09-01

    The aim of the present study was to investigate whether nasal nitric oxide (nNO) levels change in relation to high altitude in a natural setting where the weather conditions were favorable. The present study included 41 healthy volunteers without a history of acute rhinosinusitis within 3 weeks and nasal polyposis. The study group consisted of 31 males (76 %) and 10 females (24 %) and the mean age of the study population was 38 ± 10 years. The volunteers encamped for 2 days in a mountain village at an altitude of 1,500 m above sea level (masl) and proceeded to highlands at an altitude of 2,200 masl throughout the day. The measurements of nNO were done randomly, either first at the mountain village or at sea level. Each participant had nNO values both at sea level and at high altitude at the end of the study. The nNO values of sea level and high altitude were compared to investigate the effect of high altitude on nNO levels. The mean of average nNO measurements at the high altitude was 74.2 ± 41 parts-per-billion (ppb) and the mean of the measurements at sea level was 93.4 ± 45 ppb. The change in nNO depending on the altitude level was statistically significant (p < 0.001). The current investigation showed that nNO levels were decreased at high altitude even if the weather conditions were favorable, such as temperature, humidity, and wind. PMID:24972544

  16. Comparison of sprite initiation altitudes between observations and models

    NASA Astrophysics Data System (ADS)

    Gamerota, W. R.; Cummer, S. A.; Li, J.; Stenbaek-Nielsen, H. C.; Haaland, R. K.; McHarg, M. G.

    2011-02-01

    Simultaneous analyses of measured sprite initiation altitudes with predicted initiation altitudes from simulations enable an examination of our understanding of the sprite initiation mechanism and the modeling techniques to simulate this mesospheric electrical phenomenon. In this work, we selected a subset of sprites optically observed from Langmuir Laboratory, NM; locations near Las Vegas, NM, in 2007 and near Portales, NM, in 2008; and a Duke University field station. The sprites were observed by high-speed imaging with time resolutions of at least 1 ms and by low light level imagers. Sprite initiation altitudes were determined by triangulation between Langmuir Laboratory and either Portales or Las Vegas, while star field analysis determined the approximate measured initiation altitudes for Duke observations. These video observations were coordinated with electromagnetic field measurements from Yucca Ridge Field Station and Duke University, respectively. With a 2-D finite difference time domain model, we simulated the lightning-driven electric fields and predict the likely altitude of sprite initiation and compare these findings with the measured initiation altitude of each sprite analyzed. Of 20 discrete sprite events analyzed, both the measured and the simulation-predicted initiation altitudes indicate that long-delayed sprites tend to initiate at lower altitude. The average discrepancy between the measurements and the simulation results is 0.35 km with a standard deviation of 3.6 km. This consistency not only confirms previous results about the relationship between sprite initiation altitude and time delay but also helps to develop confidence in the models to reveal the sprite physics.

  17. Can patients with coronary heart disease go to high altitude?

    PubMed

    Dehnert, Christoph; Bärtsch, Peter

    2010-01-01

    Tourism to high altitude is very popular and includes elderly people with both manifest and subclinical coronary heart disease (CHD). Thus, risk assessment regarding high altitude exposure of patients with CHD is of increasing interest, and individual recommendations are expected despite the lack of sufficient scientific evidence. The major factor increasing cardiac stress is hypoxia. At rest and for a given external workload, myocardial oxygen demand is increased at altitude, particularly in nonacclimatized individuals, and there is some evidence that blood-flow reserve is reduced in atherosclerotic coronary arteries even in the absence of severe stenosis. Despite a possible imbalance between oxygen demand and oxygen delivery, studies on selected patients have shown that exposure and exercise at altitudes of 3000 to 3500 m is generally safe for patients with stable CHD and sufficient work capacity. During the first days at altitude, patients with stable angina may develop symptoms of myocardial ischemia at slightly lower heart rate x  blood-pressure products. Adverse cardiac events, however, such as unstable angina coronary syndromes, do not occur more frequently compared with sea level except for those who are unaccustomed to exercise. Therefore, training should start before going to altitude, and the altitude-related decrease in exercise capacity should be considered. Travel to 3500 m should be avoided unless patients have stable disease, preserved left ventricular function without residual capacity, and above-normal exercise capacity. CHD patients should avoid travel to elevations above 4500 m owing to severe hypoxia at these altitudes. The risk assessment of CHD patients at altitude should always consider a possible absence of medical support and that cardiovascular events may turn into disaster. PMID:20919884

  18. The 5-6 December 1991 FIRE IFO II jet stream cirrus case study: Possible influences of volcanic aerosols

    SciTech Connect

    Sassen, K.; Starr, D.O.C.; Melfi, S.H.; Spinhirne, J.D.; Poellot, M.R.; Eberhard, W.L.; Eloranta, E.W.; Hagen, D.E.; Hallett, J.

    1995-01-01

    In presenting an overview of the cirrus clouds comprehensively studied by ground-based and airborne sensors from Coffeyville, Kansas, during the 5-6 December 1992 Project FIRE IFO II case study period, evidence is provided that volcanic aerosols from the June 1991 Pinatubo eruptions may have significantly influenced the formation and maintenance of the cirrus. Following the local appearance of a spur of stratospheric volcanic debris from the subtropics, a series of jet streaks subsequently conditioned the troposphere through tropopause foldings with sulfur-based particles that became effective cloud-forming nuclei in cirrus clouds. Aerosol and ozone measurements suggest a complicated history of stratospheric-tropospheric exchanges embedded within the upper-level flow, and cirrus cloud formation was noted to occur locally at the boundaries of stratospheric aerosol-enriched layers that became humidified through diffusion, precipitation, or advective processes. Apparent cirrus cloud alterations include abnormally high ice crystal concentrations (up to {approximately}600 L{sup {minus}1}), complex radial ice crystal types, and relatively large haze particles in cirrus uncinus cell heads at temperatures between {minus}40{degrees} and {minus}50{degrees}C. Implications for volcanic-cirrus cloud climate effects and usual (nonvolcanic aerosol) jet stream cirrus cloud formation are discussed. 42 refs., 25 figs., 3 tabs.

  19. Toxicity of 3,5,6-trichloro-2-pyridinol tested at multiple stages of zebrafish (Danio rerio) development.

    PubMed

    Suvarchala, Gonuguntla; Philip, Gundala Harold

    2016-08-01

    Organophosphate compounds (OP) are widely used throughout the world for pest control. 3,5,6-Trichloro-2-pyridinol (TCP) is a primary metabolite of two OP compounds namely CP and triclopyr. This study is carried out to know whether a metabolite of parent compound is doing well or harm to biota. The potential effect of TCP was evaluated on development as destabilization of any events transpiring during embryogenesis could be deleterious. To determine this, 4-hpf zebrafish embryos were exposed to five concentrations of TCP (200, 400, 600, 800, 1000 μg/L) or 99.5 % acetone (solvent control). Different early life-stage parameters were observed at four different developmental stages, 24, 48, 72 and 96 hpf. TCP-treated embryo/larvae showed increased mortality, delay in hatching time and decrease in percentage of hatched embryos. Reduction in heartbeat rate, blood flow and body and eye pigmentation was noticed in a dose-dependent manner. Pericardial and yolk sac edema were most severe malformations caused by TCP. Along with this crooked spine/notochord, tail deformation was noticed in hatched and unhatched embryos. The malformations observed provide a good starting point for examination of the molecular mechanisms that are affected during development by TCP. Results gain significance as TCP, which is a breakdown product, appears to be more toxic during development compared to parent compound, CP (our earlier publication). PMID:27121015

  20. Determination of irradiation histories of raw beef livers using liquid chromatography-tandem mass spectrometry of 5,6-dihydrothymidine.

    PubMed

    Fukui, Naoki; Takatori, Satoshi; Kitagawa, Yoko; Okihashi, Masahiro; Ishikawa, Etsuko; Fujiyama, Takatomo; Kajimura, Keiji; Furuta, Masakazu; Obana, Hirotaka

    2017-02-01

    A method for detecting irradiation histories of raw beef livers was developed by measuring 5,6-dihydrothymidine (DHdThd) using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Liver DNA was extracted using phenol-chloroform extraction followed by precipitation in 50% ethanol. DNA was then enzymatically digested and nucleosides were purified using an OASIS MCX column. DHdThd and thymidine (dThd) contents of resulting test solutions were analyzed using LC-MS/MS. DHdThd was detected specifically after γ-irradiation. Concentration ratios of DHdThd to dThd in the test solutions increased dose-dependently after irradiation at 1.0-11.3kGy, which included the practical dose for sterilization of 2-7kGy. Dose-response curves from beef livers of individual animals almost overlapped. Thus, this method is a candidate for the detection of irradiation histories of foods from which DNA can be extracted. PMID:27596408

  1. Electrochemical biosensor based on glucose oxidase encapsulated within enzymatically synthesized poly(1,10-phenanthroline-5,6-dione).

    PubMed

    Ciftci, Hakan; Oztekin, Yasemin; Tamer, Ugur; Ramanaviciene, Almira; Ramanavicius, Arunas

    2014-11-01

    This study is focused on the investigation of electrocatalytic effect of glucose oxidase (GOx) immobilized on the graphite rod (GR) electrode. The enzyme modified electrode was prepared by encapsulation of immobilized GOx within enzymatically formed poly(1,10-phenanthroline-5,6-dione) (pPD) film. The electrochemical responses of such enzymatic electrode (pPD/GOx/GR) vs. different glucose concentrations were examined chronoamperometrically in acetate-phosphate buffer solution (A-PBS), pH 6.0, under aerobic or anaerobic conditions. Amperometric signals of the pPD/GOx/GR electrode exhibited well-defined hyperbolic dependence upon glucose concentration. Amperometric signals at 100mM of glucose were 41.17 and 32.27 μA under aerobic and anaerobic conditions, respectively. Amperometric signals of the pPD/GOx/GR electrode decreased by 6% within seven days. The pPD/GOx/GR electrode showed excellent selectivity in the presence of dopamine and uric acid. Furthermore it had a good reproducibility and repeatability with standard deviation of 9.4% and 8.0%, respectively. PMID:25454754

  2. Arabidopsis inositol 1,3,4-trisphosphate 5/6 kinase 2 is required for seed coat development.

    PubMed

    Tang, Yong; Tan, Shutang; Xue, Hongwei

    2013-07-01

    Inositol 1,3,4-trisphosphate 5/6 kinase (ITPK) phosphorylates inositol 1,3,4-trisphosphate to form inositol 1,3,4,5-tetrakisphosphate and inositol 1,3,4,6-tetrakisphosphate which can be finally transferred to inositol hexaphosphate (IP₆) and play important roles during plant growth and development. There are 4 putative ITPK members in Arabidopsis. Expression pattern analysis showed that ITPK2 is constitutively expressed in various tissues. A T-DNA knockout mutant of ITPK2 was identified and scanning electron microscopy (SEM) analysis showed that the epidermis structure of seed coat was irregularly formed in seeds of itpk2-1 mutant, resulting in the increased permeability of seed coat to tetrazolium salts. Further analysis by gas chromatography coupled with mass spectrometry of lipid polyester monomers in cell wall confirmed a dramatic decrease in composition of suberin and cutin, which relate to the permeability of seed coat and the formation of which is accompanied with seed coat development. These results indicate that ITPK2 plays an essential role in seed coat development and lipid polyester barrier formation. PMID:23595027

  3. Acid-coated Textiles (pH 5.5-6.5)--a New Therapeutic Strategy for Atopic Eczema?

    PubMed

    Jaeger, Teresa; Rothmaier, Markus; Zander, Holger; Ring, Johannes; Gutermuth, Jan; Anliker, Mark D

    2015-07-01

    Increased transepidermal water loss (TEWL) and decreased skin capacitance are characteristic features of the disturbed epidermal barrier in atopic eczema (AE). The "acid mantle", which is a slightly acidic film on the surface of the skin has led to the development of acidic emollients for skin care. In this context, the effect of citric acid-coated textiles on atopic skin has not been examined to date. A textile carrier composed of cellulose fibres was coated with a citric acid surface layer by esterification, ensuring a constant pH of 5.5-6.5. Twenty patients with AE or atopic diathesis were enrolled in the study. In a double-blind, half-side experiment, patients had to wear these textiles for 12 h a day for 14 days. On day 0 (baseline), 7 and 14, tolerability (erythema, pruritus, eczema, wearing comfort) and efficacy on skin barrier were assessed by TEWL skin hydration (corneometry/capacitance), pH and clinical scoring of eczema (SCORAD). Citric acid-coated textiles were well tolerated and improved eczema and objective parameters of skin physiology, including barrier function and a reduced skin surface pH, with potential lower pathogenic microbial colonisation. PMID:24953993

  4. The 5-6 December 1991 FIRE IFO 2 Jet Stream Cirrus Case Study: Possible Influences of Volcanic Aerosols

    NASA Technical Reports Server (NTRS)

    Sassen, Kenneth; Starr, David OC.; Mace, Gerald G.; Poellot, Michael R.; Melfi, S. H.; Eberhard, Wynn L.; Spinhirne, James D.; Eloranta, E. W.; Hagen, Donald E.; Hallett, John

    1996-01-01

    In presenting an overview of the cirrus clouds comprehensively studied by ground based and airborne sensors from Coffeyville, Kansas, during the 5-6 December 1992 First ISCCP Regional Experiment (FIRE) intensive field observation (IFO) case study period, evidence is provided that volcanic aerosols from the June 1991 Pinatubo eruptions may have significantly influenced the formation and maintenance of the cirrus. Following the local appearance of a spur of stratospheric volcanic debris from the subtropics, a series of jet streaks subsequently conditioned the troposphere through tropopause foldings with sulfur based particles that became effective cloud forming nuclei in cirrus clouds. Aerosol and ozone measurements suggest a complicated history of stratospheric-tropospheric exchanges embedded with the upper level flow, and cirrus cloud formation was noted to occur locally at the boundaries of stratospheric aerosol enriched layers that became humidified through diffusion, precipitation, or advective processes. Apparent cirrus cloud alterations include abnormally high ice crystal concentrations (up to approximately 600 L(exp. 1)), complex radial ice crystal types, and relatively large haze particles in cirrus uncinus cell heads at temperatures between -40 and -50 degrees C. Implications for volcanic-cirrus cloud climate effects and unusual (nonvolcanic) aerosol jet stream cirrus cloud formation are discussed.

  5. Comprehensive Synthesis of Monohydroxy-Cucurbit[n]urils (n = 5, 6, 7, 8): High Purity and High Conversions.

    PubMed

    Ayhan, Mehmet M; Karoui, Hakim; Hardy, Micaël; Rockenbauer, Antal; Charles, Laurence; Rosas, Roselyne; Udachin, Konstantin; Tordo, Paul; Bardelang, David; Ouari, Olivier

    2015-08-19

    We describe a photochemical method to introduce a single alcohol function directly on cucurbit[n]urils (n = 5, 6, 7, 8) with conversions of the order 95-100% using hydrogen peroxide and UV light. The reaction was easily scaled up to 1 g for CB[6] and CB[7]. Spin trapping of cucurbituril radicals combined with MS experiments allowed us to get insights about the reaction mechanism and characterize CB[5], CB[6], CB[7], and CB[8] monofunctional compounds. Experiments involving (18)O isotopically labeled water indicated that the mechanism was complex and showed signs of both radical and ionic intermediates. DFT calculations allowed estimating the Bond Dissociation Energies (BDEs) of each hydrogen atom type in the CB series, providing an explanation of the higher reactivity of the "equatorial" C-H position of CB[n] compounds. These results also showed that, for CB[8], direct functionalization on the cucurbituril skeleton is more difficult because one of the methylene hydrogen atoms (Hb) has its BDE lowering within the series and coming close to that of Hc, thus opening the way to other types of free radicals generated on the CB[8] skeleton leading to several side products. Yet CB[5]-(OH)1 and CB[8]-(OH)1, the first CB[8] derivative, were obtained in excellent yields thanks to the soft method presented here. PMID:26197228

  6. Magnetic properties of YMn{sub x}Al{sub 12{minus}x}(x = 4,5,6)

    SciTech Connect

    Coldea, M.; Coldea, R.; Borodi, G.

    1994-03-01

    Magnetic susceptibility of YMn{sub x}Al{sub 12{minus}x} (x=4,5,6) with ThMn{sub 12} structure was measured at temperatures 90K to 900K. These compounds show varied magnetic behaviors depending upon the relative abundance of Mn atoms in the 8f, 8j and 8i crystallographic sites. In the high temperature range, the temperature dependence of the susceptibility is of the Curie-Weiss type. The occurrence of a Mn moment in YMn{sub 4}Al{sub 8} and YMn{sub 8}Al{sub 6} is strongly correlated with the critical value d{approx}2.6{angstrom} of MD-Mn distance below which the Mn moment collapses. In YMn{sub 8}Al{sub 6} both the magnetic and the nonmagnetic Mn atoms were observed to coexist. It has been revealed that the magnetic character of Mn moment in the 8f sites of these two compounds changes from an itinerant electron type to a local moment type with increasing temperature. A transition to a spin glass state at low temperatures for YMn{sub 5}Al{sub 7}, was suggested.

  7. Lipoic acid does not improve renal function markers in 5/6 nephrectomy model: possible role of Nrf2 inactivation.

    PubMed

    Lo, Sze M; Dal Lin, Fernando T; Soares, Maria F; Hauser, Aline B; Pecoits-Filho, Roberto; Nakao, Lia S

    2016-05-01

    Chronic kidney disease (CKD) progression and complications are associated with increased oxidative stress, as well as with Nrf2 inactivation. Lipoic acid (LA) has been considered an inducer of Nrf2 antioxidant response. We tested whether oral administration of LA provides beneficial effects in experimental CKD in rats. Wistar rats underwent 5/6 nephrectomy (CKD group) or sham laparotomy. Seven days later, CKD group was divided into three subgroups that received: (i) LA continuously in the drinking water (100 mg/kg/day), (ii) LA by gavage every other day (100 mg/kg), or (iii) no LA treatment. LA treatment lasted until day 60. Plasma urea and creatinine, 24 h-proteinuria, glomerulosclerosis, interstitial fibrosis/tubular atrophy, and Nrf2 activation were analyzed. All parameters measured were significantly altered in the untreated CKD group, compared with the sham group, as expected. Oral LA administration, either in the drinking water or by gavage, did not improve significantly any parameter, comparing the treated-groups with the untreated CKD group. These results indicate that oral LA administration for 53 days was ineffective to reactivate Nrf2 in the remnant kidney of uremic rats, likely preventing improvements in biochemical and histopathological markers of renal function. PMID:26904958

  8. Improved propionic acid and 5,6-dimethylbenzimidazole control strategy for vitamin B12 fermentation by Propionibacterium freudenreichii.

    PubMed

    Wang, Peng; Zhang, Zhiwei; Jiao, Youjing; Liu, Shouxin; Wang, Yunshan

    2015-01-10

    An efficient fermentation-strengthening approach was developed to improve the anaerobic production of vitamin B12 by cultivation process optimization with Propionibacterium freudenreichii. The effects of the byproduct propionic acid and the precursor 5,6-dimethylbenzimidazole (DMB) on vitamin B12 biosynthesis were investigated. Byproduct inhibition experiments showed that maintaining propionic acid concentration in broth below 10-20 g/L in the early stage and 20-30 g/L in the late stage can efficiently improve vitamin B12 biosynthesis. Batch fermentation indicated the occurrence of feed-back inhibition in intracellular intermediate biosynthesis. In addition, the incorporation of the precursor DMB depended on the fermentation level of the vitamin B12 intermediate. High vitamin B12 concentration (58.8 mg/L) and production (0.37 mg/g) were obtained with an expanded bed adsorption bioreactor by using the propionic acid and DMB control method. The optimum concentration and production of 59.5 and 0.59 mg/L h for vitamin B12 production were respectively achieved after five continuous batches. PMID:25455014

  9. Finite-fault slip model of the 2011 Mw 5.6 Prague, Oklahoma earthquake from regional waveforms

    USGS Publications Warehouse

    Sun, Xiaodan; Hartzell, Stephen

    2014-01-01

    The slip model for the 2011 Mw 5.6 Prague, Oklahoma, earthquake is inferred using a linear least squares methodology. Waveforms of six aftershocks recorded at 21 regional stations are used as empirical Green's functions (EGFs). The solution indicates two large slip patches: one located around the hypocenter with a depth range of 3–5.5 km; the other located to the southwest of the epicenter with a depth range from 7.5 to 9.5 km. The total moment of the solution is estimated at 3.37 × 1024 dyne cm (Mw 5.65). The peak slip and average stress drop for the source at the hypocenter are 70 cm and 90 bars, respectively, approximately one half the values for the Mw 5.8 2011 Mineral, Virginia, earthquake. The stress drop averaged over all areas of slip is 16 bars. The relatively low peak slip and stress drop may indicate an induced component in the origin of the Prague earthquake from deep fluid injection.

  10. Synthesis and anticancer activities of 5,6,7-trimethoxy-N-phenyl(ethyl)-4-aminoquinazoline derivatives.

    PubMed

    Zhang, Ying; Jin, Linhong; Xiang, Hongmei; Wu, Jian; Wang, Peiyi; Hu, Deyu; Xue, Wei; Yang, Song

    2013-08-01

    A series of 5,6,7-trimethoxy-N-phenyl(ethyl)-4-aminoquinazoline compounds was prepared by microwave irradiation and conventional heating methods. Compounds 6p, 6q, and 6x strongly inhibited extracellular regulated kinase1/2 (ERK1/2) phosphorylation induced by epidermal growth factor (EGF) at 1.28 μM in PC3 cells. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that all compounds had certain anticancer activities, and the IC₅₀ values of 6x were 6.2 ± 0.9, 3.2 ± 0.1, and 3.1 ± 0.1 μM against PC3, BGC823, and Bcap37 cells, respectively. Acridine orange/ethidium bromide staining, Hoechst 33258 staining, DNA ladder, and flow cytometry analyses revealed that 6x induced cell apoptosis in PC3 cells, with apoptosis ratios of 11.6% at 1 μM and 31.8% at 10 μM after 72 h. PMID:23811258

  11. Electron density determinations of stellar coronae using Fe XXI ndarrow2p (n=3,4,5,6) transitions

    NASA Astrophysics Data System (ADS)

    Chen, H.; Beiersdorfer, P.; Liedahl, D. A.; Bitter, M.; Brown, G. V.; Kahn, S. M.

    2002-04-01

    The idea of using L-shell iron spectroscopic information to infer the electron density has become very attractive following the availability of high-resolution data measured by current x-ray observatories. Following suggestions in [1], we developed the n darrow2p line (n=3,4,5,6) intensities in Fe XXI as a diagnostic that is sensitive to densities near 10^13 cm-3 and applied it to Chandra observations of HR1099. HULLAC code predictions of the density sensitivity were checked with the Livermore EBIT-II ion trap for low densities. Checks at high density are in progress at the Princeton NSTX tokamak. For HR1099 we find a density of about 2 to 8 x 10^13 cm-3. This is in the range of 10^12 - 10^13 cm-3 that was determined using the Fe XXI EUV line ratios (102/128 ÅÅobserved with EUVE [2]. This work was performed under the auspice of DOE by UC-LLNL under contract W-7405-Eng-48 and supported by DOE OFES and by NASA SARA grants to LLNL, GSFC, PPPL and Columbia University.\\$[1]. Wargelin, et al, APJ 496 (1998). [2]. Ayres,et al, APJ, 549, (2001) 554)

  12. Rapid and sensitive spectrofluorimetric determination of enrofloxacin, levofloxacin and ofloxacin with 2,3,5,6-tetrachloro- p-benzoquinone

    NASA Astrophysics Data System (ADS)

    Ulu, Sevgi Tatar

    2009-06-01

    A highly sensitive spectrofluorimetric method was developed for the first time, for the analysis of three fluoroquinolones (FQ) antibacterials, namely enrofloxacin (ENR), levofloxacin (LEV) and ofloxacin (OFL) in pharmaceutical preparations through charge transfer (CT) complex formation with 2,3,5,6-tetrachloro- p-benzoquinone (chloranil,CLA). At the optimum reaction conditions, the FQ-CLA complexes showed excitation maxima ranging from 359 to 363 nm and emission maxima ranging from 442 to 488 nm. Rectilinear calibration graphs were obtained in the concentration range of 50-1000, 50-1000 and 25-500 ng mL -1 for ENR, LEV and OFL, respectively. The detection limit was found to be 17 ng mL -1 for ENR, 17 ng mL -1 for LEV, 8 ng mL -1 for OFL, respectively. Excipients used as additive in commercial formulations did not interfere in the analysis. The method was validated according to the ICH guidelines with respect to specificity, linearity, accuracy, precision and robustness. The proposed method was successfully applied to the analysis of pharmaceutical preparations. The results obtained were in good agreement with those obtained using the official method; no significant difference in the accuracy and precision as revealed by the accepted values of t- and F-tests, respectively.

  13. Phosphorylation regulates proteolytic efficiency of TEV protease detected by a 5(6)-carboxyfluorescein-pyrene based fluorescent sensor.

    PubMed

    He, Yao-Hui; Li, Yan-Mei; Chen, Yong-Xiang

    2016-04-01

    TEV protease is of great importance for in vitro and in vivo site-specific cleavage of proteins. The proteolytic efficiency of TEV protease is often regulated by mutation of the substrate, which is irreversible and hard to be modulated. Herein, a facile and reversible method, based on phosphorylation in the substrate, is developed to regulate the cleavage capability of TEV protease. Phosphorylation at P3 tyrosine hinders the recognition of TEV protease to the substrate by using a robust fluorescent protease sensor. Moreover, the phosphate group can be easily removed by alkaline phosphatases for recovering the proteolytic efficiency of TEV protease. Additionally, 5(6)-carboxyfluorescein and pyrene have been used as high-efficiency mutual fluorophore-quencher pair in the peptide-based protease sensor for the first time, which provides a chance to simultaneously monitor the cleavage process in two respective fluorescence channels. Further studies indicated both dynamic and static components contributing to the mutual quenching system. The phosphorylation-regulated TEV protease proteolysis system can be used in conditional cleavage of protein or peptide tag. PMID:26838417

  14. Turbulent mixing in high-altitude explosions

    SciTech Connect

    Kuhl, A.L.; Bell, J.B. ); Ferguson, R.E. ); White, W.W.; McCartor, T.H. )

    1992-09-01

    Numerical simulations of a high-altitude explosion were performed using a Godunov code with Adaptive Mesh Refinement (AMR). The code solves the two-dimensional (2-D), time-dependent conservation laws of inviscid gas dynamics while AMR is used to focus the computational effort in the mixing regions. The calculations revealed that a spherical density interface embedded in this flow was unstable and rolled up into a turbulent mixing layer. The shape of the interface was qualitatively similar to experimental photographs. Initially, the mixing layer width grew as a linear function of time, but eventually it reached an asymptotically-constant value. The flow field was azimuthally-averaged to evaluate the mean-flow profiles and the R.M.S. fluctuation profiles across the mixing layer. The mean kinetic energy rapidly approached zero as the blast wave decayed, but the fluctuating kinetic energy asymptotically approached a small constant value (a fraction of a percent of the maximum kinetic energy). This represents the rotational kinetic energy driven by the vorticity field, that continued to mix the fluid indefinitely. It was shown that the vorticity field corresponds to a function that fluctuates between plus and minus values -- with a volume-averaged mean of zero. The amplitude of the vorticity fluctuations decayed as t[sup [minus]1]. The corresponding enstrophy increased linearly with time because of a cascade process for the mean-squared vorticity. This result is in good agreement with the 2-D calculations of turbulent flow as reported by G.K. Batchelor. The problem should be recalculated in 3-D to study the decay of turbulent mixing for spherical interfaces.

  15. Turbulent mixing in high-altitude explosions

    SciTech Connect

    Kuhl, A.L.; Bell, J.B.; Ferguson, R.E.; White, W.W.; McCartor, T.H.

    1992-09-01

    Numerical simulations of a high-altitude explosion were performed using a Godunov code with Adaptive Mesh Refinement (AMR). The code solves the two-dimensional (2-D), time-dependent conservation laws of inviscid gas dynamics while AMR is used to focus the computational effort in the mixing regions. The calculations revealed that a spherical density interface embedded in this flow was unstable and rolled up into a turbulent mixing layer. The shape of the interface was qualitatively similar to experimental photographs. Initially, the mixing layer width grew as a linear function of time, but eventually it reached an asymptotically-constant value. The flow field was azimuthally-averaged to evaluate the mean-flow profiles and the R.M.S. fluctuation profiles across the mixing layer. The mean kinetic energy rapidly approached zero as the blast wave decayed, but the fluctuating kinetic energy asymptotically approached a small constant value (a fraction of a percent of the maximum kinetic energy). This represents the rotational kinetic energy driven by the vorticity field, that continued to mix the fluid indefinitely. It was shown that the vorticity field corresponds to a function that fluctuates between plus and minus values -- with a volume-averaged mean of zero. The amplitude of the vorticity fluctuations decayed as t{sup {minus}1}. The corresponding enstrophy increased linearly with time because of a cascade process for the mean-squared vorticity. This result is in good agreement with the 2-D calculations of turbulent flow as reported by G.K. Batchelor. The problem should be recalculated in 3-D to study the decay of turbulent mixing for spherical interfaces.

  16. High altitude cerebral oedema during adventure training on Mount Kenya.

    PubMed

    Raitt, S

    2012-09-01

    The trekking ascent to Point Lenana (4,985m) on Mount Kenya is a popular objective for soldiers on adventurous training in Kenya. The standard route previously taken has been the Naro Moru route which involves an ascent rate far in excess of that recommended to avoid altitude illness. This article describes the case of a British soldier who developed high altitude cerebral oedema during an ascent of Point Lenana via the Naro Moro route. Recommendations to reduce the risk of altitude illness on Mount Kenya include alternative and more gradual routes of ascent. Early symptom recognition and descent are vital to prevent clinical deterioration. PMID:23472574

  17. Composition of the hot plasma near geosynchronous altitude

    NASA Technical Reports Server (NTRS)

    Johnson, R. G.; Sharp, R. D.; Shelley, E. G.

    1977-01-01

    Although there were no direct measurements of the composition of the hot (keV) plasma at geosynchronous altitudes, the combination of other observations leads to the conclusion that, at least during geomagnetically disturbed periods, there are significant fluxes of ions heavier than protons in this region. Ion composition measurements below 8000 km altitude show upward streaming fluxes of both O(+) and H(+) ions in the L-region of the geosynchronous orbit. These observations are consistent with the conclusion that at least a portion of the total ion fluxes observed at geosynchronous altitude to be highly peaked near the magnetic field lines are heavier than protons and originate in the ionosphere.

  18. 14 CFR 91.217 - Data correspondence between automatically reported pressure altitude data and the pilot's...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... maintain flight altitude, with that altimeter referenced to 29.92 inches of mercury for altitudes from sea level to the maximum operating altitude of the aircraft; or (c) Unless the altimeters and digitizers...

  19. Long-Term Exposure to High Altitude Affects Conflict Control in the Conflict-Resolving Stage

    PubMed Central

    Wu, Jianhui; Wang, Baoxi; Guo, Shichun; Luo, Ping; Han, Buxin

    2015-01-01

    The neurocognitive basis of the effect of long-term high altitude exposure on conflict control is unclear. Event related potentials (ERPs) were recorded in a flanker task to investigate the influence of high altitude on conflict control in the high-altitude group (who had lived at high altitude for three years but were born at low altitude) and the low-altitude group (living in low altitude only). Although altitude effect was not significant at the behavioral level, ERPs showed cognitive conflict modulation. The interaction between group and trial type was significant: P3 amplitude was greater in the low-altitude group than in the high-altitude group in the incongruent trial. This result suggests that long-term exposure to high altitude affects conflict control in the conflict-resolving stage, and that attentional resources are decreased to resist the conflict control in the high-altitude group. PMID:26671280

  20. Model of Atmospheric Links on Optical Communications from High Altitude

    NASA Technical Reports Server (NTRS)

    Subich, Christopher

    2004-01-01

    Optical communication links have the potential to solve many of the problems of current radio and microwave links to satellites and high-altitude aircraft. The higher frequency involved in optical systems allows for significantly greater signal bandwidth, and thus information transfer rate, in excess of 10 Gbps, and the highly directional nature of laser-based signals eliminates the need for frequency-division multiplexing seen in radio and microwave links today. The atmosphere, however, distorts an optical signal differently than a microwave signal. While the ionosphere is one of the most significant sources of noise and distortion in a microwave or radio signal, the lower atmosphere affects an optical signal more significantly. Refractive index fluctuations, primarily caused by changes in atmospheric temperature and density, distort the incoming signal in both deterministic and nondeterministic ways. Additionally, suspended particles, such as those in haze or rain, further corrupt the transmitted signal. To model many of the atmospheric effects on the propagating beam, we use simulations based on the beam-propagation method. This method, developed both for simulation of signals in waveguides and propagation in atmospheric turbulence, separates the propagation into a diffraction and refraction problem. The diffraction step is an exact solution, within the limits of numerical precision, to the problem of propagation in free space, and the refraction step models the refractive index variances over a segment of the propagation path. By applying refraction for a segment of the propagation path, then diffracting over that same segment, this method forms a good approximation to true propagation through the atmospheric medium. Iterating over small segments of the total propagation path gives a good approximation to the problem of propagation over the entire path. Parameters in this model, such as initial beam profile and atmospheric constants, are easily modified in a

  1. Whole-genome sequencing of six dog breeds from continuous altitudes reveals adaptation to high-altitude hypoxia

    PubMed Central

    Gou, Xiao; Wang, Zhen; Li, Ning; Qiu, Feng; Xu, Ze; Yan, Dawei; Yang, Shuli; Jia, Jia; Kong, Xiaoyan; Wei, Zehui; Lu, Shaoxiong; Lian, Linsheng; Wu, Changxin; Wang, Xueyan; Li, Guozhi; Ma, Teng; Jiang, Qiang; Zhao, Xue; Yang, Jiaqiang; Liu, Baohong; Wei, Dongkai; Li, Hong; Yang, Jianfa; Yan, Yulin; Zhao, Guiying; Dong, Xinxing; Li, Mingli; Deng, Weidong; Leng, Jing; Wei, Chaochun; Wang, Chuan; Mao, Huaming; Zhang, Hao; Ding, Guohui; Li, Yixue

    2014-01-01

    The hypoxic environment imposes severe selective pressure on species living at high altitude. To understand the genetic bases of adaptation to high altitude in dogs, we performed whole-genome sequencing of 60 dogs including five breeds living at continuous altitudes along the Tibetan Plateau from 800 to 5100 m as well as one European breed. More than 150× sequencing coverage for each breed provides us with a comprehensive assessment of the genetic polymorphisms of the dogs, including Tibetan Mastiffs. Comparison of the breeds from different altitudes reveals strong signals of population differentiation at the locus of hypoxia-related genes including endothelial Per-Arnt-Sim (PAS) domain protein 1 (EPAS1) and beta hemoglobin cluster. Notably, four novel nonsynonymous mutations specific to high-altitude dogs are identified at EPAS1, one of which occurred at a quite conserved site in the PAS domain. The association testing between EPAS1 genotypes and blood-related phenotypes on additional high-altitude dogs reveals that the homozygous mutation is associated with decreased blood flow resistance, which may help to improve hemorheologic fitness. Interestingly, EPAS1 was also identified as a selective target in Tibetan highlanders, though no amino acid changes were found. Thus, our results not only indicate parallel evolution of humans and dogs in adaptation to high-altitude hypoxia, but also provide a new opportunity to study the role of EPAS1 in the adaptive processes. PMID:24721644

  2. Stepped inlet optical panel

    DOEpatents

    Veligdan, James T.

    2001-01-01

    An optical panel includes stacked optical waveguides having stepped inlet facets collectively defining an inlet face for receiving image light, and having beveled outlet faces collectively defining a display screen for displaying the image light channeled through the waveguides by internal reflection.

  3. Steps Toward Effective Assessment.

    ERIC Educational Resources Information Center

    Cope, Carolyn O.

    1996-01-01

    Describes and defines the steps involved in measurement and evaluation: (1) determining an outcome; (2)defining scoring criteria; (3)establishing appropriate assessment tasks; and (4)creating opportunities for learning. Includes a flow chart for a design-down curriculum and an example of a vocal performance rating scale assessment. (MJP)

  4. Thermodynamic relationship between structural isomers of the thermochromic compound bis(N-Isopropyl-5,6-benzosalicylideneiminato)nickel(II).

    PubMed

    Wang, Qi; Takeuchi, Akira; Yamamura, Yasuhisa; Saito, Kazuya; Mori, Wasuke; Sorai, Michio

    2008-09-01

    A pair of structural isomers was isolated at room temperature for the thermochromic nickel complex bis( N-isopropyl-5,6-benzosalicylideneiminato)nickel(II); one is a diamagnetic green form with square-planar coordination geometry (G phase), and the other is a paramagnetic brown form with a tetrahedral geometry (B phase). However, a question as to which form is thermodynamically stable was left open. To solve this problem, thermal and magnetic properties of this complex were investigated by adiabatic heat capacity calorimetry in the 6-508 K temperature range and magnetic measurements in the 2-400 K region. In addition to the two forms previously reported, two metastable crystal forms (G' and B' phases) were found. The stable phase sequence was G phase, B phase, and then liquid upon heating. The supercooled B phase gave rise to a small phase transition with nonmagnetic origin at around 50 K. By rapidly cooling the liquid, a glassy liquid state was realized below approximately 290 K. The order of thermodynamic stability at 298.15 K was revealed to be the G, B, G', and then the B' phase. The entropy, enthalpy, and Gibbs energy differences between the B and the G phases at 298.15 K were S degrees (B) - S degrees (G) = 32.8 J K (-1) mol (-1), H degrees (B) - H degrees (G) = 16.0 kJ mol (-1), and G degrees (B) - G degrees (G) = 6.25 kJ mol (-1), respectively. PMID:18698710

  5. Inhibition of Bovine Viral Diarrhea Virus RNA Synthesis by Thiosemicarbazone Derived from 5,6-Dimethoxy-1-Indanone▿

    PubMed Central

    Castro, Eliana F.; Fabian, Lucas E.; Caputto, María E.; Gagey, Dolores; Finkielsztein, Liliana M.; Moltrasio, Graciela Y.; Moglioni, Albertina G.; Campos, Rodolfo H.; Cavallaro, Lucía V.

    2011-01-01

    In the present work, we described the activity of the thiosemicarbazone derived from 5,6-dimethoxy-1-indanone (TSC), which we previously characterized as a new compound that inhibits bovine viral diarrhea virus (BVDV) infection. We showed that TSC acts at a point of time that coincides with the onset of viral RNA synthesis and that it inhibits the activity of BVDV replication complexes (RCs). Moreover, we have selected five BVDV mutants that turned out to be highly resistant to TSC but still susceptible to ribavirin (RBV). Four of these resistant mutants carried an N264D mutation in the viral RNA-dependent RNA polymerase (RdRp). The remaining mutant showed an A392E mutation within the same protein. Some of these mutants replicated slower than the wild-type (wt) virus in the absence of TSC, whereas others showed a partial reversion to the wt phenotype over several passages in the absence of the compound. The docking of TSC in the crystal structure of the BVDV RdRp revealed a close contact between the indane ring of the compound and several residues within the fingers domain of the enzyme, some hydrophobic contacts, and hydrogen bonds with the thiosemicarbazone group. Finally, in the mutated RdRp from resistant BVDV, these interactions with TSC could not be achieved. Interestingly, TSC inhibited BVDV replication in cell culture synergistically with RBV. In conclusion, TSC emerges as a new nonnucleoside inhibitor of BVDV RdRp that is synergistic with RBV, a feature that turns it into a potential compound to be evaluated against hepatitis C virus (HCV). PMID:21430053

  6. Inhibition of bovine viral diarrhea virus RNA synthesis by thiosemicarbazone derived from 5,6-dimethoxy-1-indanone.

    PubMed

    Castro, Eliana F; Fabian, Lucas E; Caputto, María E; Gagey, Dolores; Finkielsztein, Liliana M; Moltrasio, Graciela Y; Moglioni, Albertina G; Campos, Rodolfo H; Cavallaro, Lucía V

    2011-06-01

    In the present work, we described the activity of the thiosemicarbazone derived from 5,6-dimethoxy-1-indanone (TSC), which we previously characterized as a new compound that inhibits bovine viral diarrhea virus (BVDV) infection. We showed that TSC acts at a point of time that coincides with the onset of viral RNA synthesis and that it inhibits the activity of BVDV replication complexes (RCs). Moreover, we have selected five BVDV mutants that turned out to be highly resistant to TSC but still susceptible to ribavirin (RBV). Four of these resistant mutants carried an N264D mutation in the viral RNA-dependent RNA polymerase (RdRp). The remaining mutant showed an A392E mutation within the same protein. Some of these mutants replicated slower than the wild-type (wt) virus in the absence of TSC, whereas others showed a partial reversion to the wt phenotype over several passages in the absence of the compound. The docking of TSC in the crystal structure of the BVDV RdRp revealed a close contact between the indane ring of the compound and several residues within the fingers domain of the enzyme, some hydrophobic contacts, and hydrogen bonds with the thiosemicarbazone group. Finally, in the mutated RdRp from resistant BVDV, these interactions with TSC could not be achieved. Interestingly, TSC inhibited BVDV replication in cell culture synergistically with RBV. In conclusion, TSC emerges as a new nonnucleoside inhibitor of BVDV RdRp that is synergistic with RBV, a feature that turns it into a potential compound to be evaluated against hepatitis C virus (HCV). PMID:21430053

  7. Study of a conjugate Pc 5-6 magnetic and absorption pulsation event at subauroral latitudes in the morning sector

    SciTech Connect

    Oksman, J.; Rosenberg, T.J. ); Lanzerotti, L.J.; MaClennan, C.G. ); Singer, H.J. )

    1988-06-01

    An interval of long-period hydromagnetic wave activity occurring in the decay phase of a magnetic storm has been studied using ground-based magnetic field and cosmic noise absorption data recorded at L {approx lt} 4.2. There is some evidence in the data for the wave frequencies to be {approximately} 0.2 mHz lower at L {approximately} 3.0-3.2 than at L {approximately} 3.8-4.2. The low wave frequencies are inconsistent with resonant oscillations of the field lines within the L shell range and probable magnetosphere plasma density conditions of observation. The waves were observed to propagate westward over at least 3 hours of local time, near dawn. An azimuthal wave number m {approx} 9 and a westward phase velocity varying from {approximately} 2.5 to {approximately} 7.5 km s{sup {minus}1} at 55{degree} magnetic latitude characterized the event. The low azimuthal phase velocities make it unlikely that the waves were generated by the Kelvin-Helmholtz instability on the magnetopause. These Pc 5-6 waves appear to be odd mode, locally driven nonresonant oscillations. The ULF wave generation and propagation were most likely located on geomagnetic field lines in the range 3.5 {approx lt} L {approx lt} 6 in the region of hot storm time plasma outside the plasmapause where a gradient in particle precipitation flux was also observed. Neither the drift mirror instability nor the compressional drift wave instability appears to be a likely source for these waves. Modulation by the ULF waves of the pitch angle diffusion of energetic electrons injected into outer radiation zone during the magnetospheric storm is suggested to account for the cosmic noise absorption pulsations observed outside the plasmapause. Irregular plasma density gradients in this region, inferred from the propagation characteristics of whistler mode VLF signals, may have caused the observed H-D plane wave polarization variations.

  8. Synthesis and anticancer activities of 4-(4-substituted piperazin)-5,6,7-trialkoxy quinazoline derivatives.

    PubMed

    Zhang, Ying; Huang, Yin-Jiu; Xiang, Hong-Mei; Wang, Pei-Yi; Hu, De-Yu; Xue, Wei; Song, Bao-An; Yang, Song

    2014-05-01

    A series of 4-(4-substituted piperazin)-5,6,7-trialkoxy quinazoline was prepared by conventional heating methods. Among these compounds, the crystal structure of compound 10o (CCDC: 916922) was determined by X-ray crystallography. Bioassay results showed that most target compounds had certain inhibition activities against proliferation of tumor cells, and some compounds even had good broad-spectrum inhibition activities. The ethoxyl series of compounds possessed higher inhibition activities against tumor cells than the methoxyl series of compounds. Bioactivity tests showed that the IC50 values of compound 10s against PC3, MGC803, A375, and A549 cells were 1.8, 2.8, 1.3, and 2.9 μΜ, respectively, which were much higher than those of commercial gefitinib (7.2, 7.6, 7.2, and 9.8 μM, respectively). Conversely, the IC50 values of compound 10s were very low against NH3T3, indicating only weak effect on normal cells as also proven by lactate dehydrogenase and acridine orange/ethidium bromide staining. Analyses of cell configuration and cell cycle revealed that compound 10s possibly caused cells to remain at G0/G1 phase by inhibiting cell proliferation for 24 h. Compound 10s also inhibited the phosphorylation of ERK1/2 and P38 with obvious concentration dependence. Thus, these compounds can inhibit the proliferation of A549 cells through the interruption of ERK1/2 and P38signaling pathways. PMID:24675177

  9. Pulmonary vascular disease in a rabbit a high altitude

    NASA Astrophysics Data System (ADS)

    Heath, Donald; Williams, David; Rios-Datenz, Jaime; Gosney, John

    1990-03-01

    A male weanling rabbit of the New Zealand White strain, born and living at an altitude of 3800 m in La Paz, Bolivia, developed right ventricular hypertrophy. This was found to be associated with growth of vascular smooth muscle cells in the intima of pulmonary arterioles, and contrasted with muscularization of the walls of pulmonary arterioles, without extension into the intima, found in a healthy, high-altitude control rabbit of the same strain. A low-altitude control showed no such muscularization. It is concluded that alveolar hypoxia, acting directly or through an intermediate agent, is a growth factor for vascular smooth muscle cells in pulmonary arterioles. This is the first report of pulmonary vascular disease due to high altitude in rabbits.

  10. Preparing for Hiking and Rock-Climbing At Altitude

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.

    2002-01-01

    Exposure to altitude with or without exercise usually results in body dehydration. Psychological and physiological preparation for exercise at altitude involves consideration of maintaining body warmth in a cool to cold environment with progressively lower oxygen content (partial pressure) as altitude increases. However, this discussion will focus on altitudes below 14,000 it where supplemental breathing oxygen is not required for sojourns of healthy people. Background information and helpful advice for those who exercise in the cold can be found in selected articles in the 2001 Winter Issue of this Newsletter: M.B. Ducharme, Get ready for outdoor winter play: prepare yourself for the cold; C. O'Brien, Think layers when dressing for exercise in the cold; B.G. Rice and R. Ellis, Let it snow, let it snow, let it snow - but be aware of winter hazards; and L.B. Mayers, Exercise - induced asthma.

  11. The radiation protection problems of high altitude and space flight

    SciTech Connect

    Fry, R.J.M.

    1993-01-01

    This paper considers the radiation environment in aircraft at high altitudes and spacecraft in low earth orbit and in deep space and the factors that influence the dose equivalents. Altitude, latitude and solar cycle are the major influences for flights below the radiation belts. In deep space, solar cycle and the occurrence of solar particle events are the factors of influence. The major radiation effects of concern are cancer and infertility in males. In high altitude aircraft the radiation consists mainly of protons and neutrons, with neutrons contributing about half the equivalent dose. The average dose rate at altitudes of transcontinental flights that approach the polar regions are greater by a factor of about 2.5 than on routes at low latitudes. Current estimates of does to air crews suggest they are well within the ICRP (1990) recommended dose limits for radiation workers.

  12. The radiation protection problems of high altitude and space flight

    SciTech Connect

    Fry, R.J.M.

    1993-04-01

    This paper considers the radiation environment in aircraft at high altitudes and spacecraft in low earth orbit and in deep space and the factors that influence the dose equivalents. Altitude, latitude and solar cycle are the major influences for flights below the radiation belts. In deep space, solar cycle and the occurrence of solar particle events are the factors of influence. The major radiation effects of concern are cancer and infertility in males. In high altitude aircraft the radiation consists mainly of protons and neutrons, with neutrons contributing about half the equivalent dose. The average dose rate at altitudes of transcontinental flights that approach the polar regions are greater by a factor of about 2.5 than on routes at low latitudes. Current estimates of does to air crews suggest they are well within the ICRP (1990) recommended dose limits for radiation workers.

  13. 14 CFR 91.177 - Minimum altitudes for IFR operations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... from the course to be flown; or (ii) In any other case, an altitude of 1,000 feet above the highest obstacle within a horizontal distance of 4 nautical miles from the course to be flown. (b) Climb. Climb...

  14. The cerebral effects of ascent to high altitudes.

    PubMed

    Wilson, Mark H; Newman, Stanton; Imray, Chris H

    2009-02-01

    Cellular hypoxia is the common final pathway of brain injury that occurs not just after asphyxia, but also when cerebral perfusion is impaired directly (eg, embolic stroke) or indirectly (eg, raised intracranial pressure after head injury). We Review recent advances in the understanding of neurological clinical syndromes that occur on exposure to high altitudes, including high altitude headache (HAH), acute mountain sickness (AMS), and high altitude cerebral oedema (HACE), and the genetics, molecular mechanisms, and physiology that underpin them. We also present the vasogenic and cytotoxic bases for HACE and explore venous hypertension as a possible contributory factor. Although the factors that control susceptibility to HACE are poorly understood, the effects of exposure to altitude (and thus hypobaric hypoxia) might provide a reproducible model for the study of cerebral cellular hypoxia in healthy individuals. The effects of hypobaric hypoxia might also provide new insights into the understanding of hypoxia in the clinical setting. PMID:19161909

  15. Calibration of infrared satellite images using high altitude aircraft measurements

    NASA Technical Reports Server (NTRS)

    Hammer, Philip D.; Gore, Warren J. Y.; Valero, Francisco P. J.

    1989-01-01

    The use of infrared radiance measurements made from high altitude aircraft for satellite image validation is discussed. Selected examples are presented to illustrate the techniques and the potentials of such validation studies.

  16. Altitude control performance of a natural energy driven stratospheric aerostat

    NASA Astrophysics Data System (ADS)

    Wu, Yao; Wang, Chao; Wang, Lei; Ma, Rong; Lu, Xiaochen; Yao, Wei

    2015-12-01

    The superheating induced overpressure is one of the key obstacles for long-endurance station-keeping of stratospheric aerostats. A novel stratospheric aerostat by utilizing the natural energy is presented and discussed in this paper. A thermo-mechanical dynamic model is established to analyze the altitude control performance of this novel aerostat. The simulation results show that the novel stratospheric aerostat can ascend to a high altitude about 25.8 km due to the combined heating effects of the solar radiation, the Earth albedo and the infrared radiation from the Earth's surface and keeps at an altitude about 22 km by the infrared radiation from the Earth's surface. In addition, the aerostat can be controlled within the desired altitude range by the simple open/close valve control strategy.

  17. System for indicating fuel-efficient aircraft altitude

    NASA Technical Reports Server (NTRS)

    Gary, B. L. (Inventor)

    1984-01-01

    A method and apparatus are provided for indicating the altitude at which an aircraft should fly so the W/d ratio (weight of the aircraft divided by the density of air) more closely approaches the optimum W/d for the aircraft. A passive microwave radiometer on the aircraft is directed at different angles with respect to the horizon to determine the air temperature, and therefore the density of the air, at different altitudes. The weight of the aircraft is known. The altitude of the aircraft is changed to fly the aircraft at an altitude at which is W/d ratio more closely approaches the optimum W/d ratio for that aircraft.

  18. Multi Rotor Uav at Different Altitudes for Slope Mapping Studies

    NASA Astrophysics Data System (ADS)

    Tahar, K. N.

    2015-08-01

    Most of consultation work only involves a small area, especially for slope mapping studies. The objective of this study is to evaluate the accuracy of slope mapping results from different altitudes at semi-undulated area and undulated area. Multi-rotor UAV is used as an instrument for data acquisition for this study. The images of slope were captured from five different altitudes in the same study area. All images were processed using photogrammetric software to produce digital elevation models and digital orthophoto. In this study, slope map from all different altitudes were identified and recorded for analysis purposes. It was found that the accuracy of slope is increase when altitude is increase. In conclusion, the condition of slope such as semi-undulated and undulated area did have an influence on the slope accuracy.

  19. The Altitude Laboratory for the Test of Aircraft Engines

    NASA Technical Reports Server (NTRS)

    Dickinson, H C; Boutell, H G

    1920-01-01

    Report presents descriptions, schematics, and photographs of the altitude laboratory for the testing of aircraft engines constructed at the Bureau of Standards for the National Advisory Committee for Aeronautics.

  20. Aging, Tolerance to High Altitude, and Cardiorespiratory Response to Hypoxia.

    PubMed

    Richalet, Jean-Paul; Lhuissier, François J

    2015-06-01

    Richalet, Jean-Paul, and François J. Lhuissier. Aging, tolerance to high altitude, and cardiorespiratory response to hypoxia. High Alt Med Biol. 16:117-124, 2015.--It is generally accepted that aging is rather protective, at least at moderate altitude. Some anecdotal reports even mention successful ascent of peaks over 8000 m and even Everest by elderly people. However, very few studies have explored the influence of aging on tolerance to high altitude and prevalence of acute high altitude related diseases, taking into account all confounding factors such as speed of ascent, altitude reached, sex, training status, and chemo-responsiveness. Changes in physiological responses to hypoxia with aging were assessed through a cross-sectional 20-year study including 4675 subjects (2789 men, 1886 women; 14-85 yrs old) and a longitudinal study including 30 subjects explored at a mean 10.4-year interval. In men, ventilatory response to hypoxia increased, while desaturation was less pronounced with aging. Cardiac response to hypoxia was blunted with aging in both genders. Similar results were found in the longitudinal study, with a decrease in cardiac and an increase in ventilatory response to hypoxia with aging. These adaptive responses were less pronounced or absent in post-menopausal untrained women. In conclusion, in normal healthy and active subjects, aging has no deleterious effect on cardiac and ventilatory responses to hypoxia, at least up to the eighth decade. Aging is not a contraindication for high altitude, as far as no pathological condition interferes and physical fitness is compatible with the intensity of the expected physical demand of one's individual. Physiological evaluation through hypoxic exercise testing before going to high altitude is helpful to detect risk factors of severe high altitude-related diseases. PMID:25946570

  1. Altitude performance evaluation of J71-A-11 turbojet engine

    NASA Technical Reports Server (NTRS)

    Useller, James W; Pappas, George E

    1956-01-01

    Data were obtained with five exhaust-nozzle areas and with the variable-area exhaust nozzle interlinked with the control system at conditions simulating flight at a Mach number of 0.8 and altitudes of 35,00 and 45,000 feet. Data simulating operation at zero flight Mach number at an altitude of 15,000 feet are also included. Engine component performance data are presented in addition to the overall engine performance.

  2. Using the NPSS Environment to Model an Altitude Test Facility

    NASA Technical Reports Server (NTRS)

    Lavelle, Thomas M.; Owen, Albert K.; Huffman, Brian C.

    2013-01-01

    An altitude test facility was modeled using Numerical Propulsion System Simulation (NPSS). This altitude test facility model represents the most detailed facility model developed in the NPSS architecture. The current paper demonstrates the use of the NPSS system to define the required operating range of a component for the facility. A significant number of additional component models were easily developed to complete the model. Discussed in this paper are the additional components developed and what was done in the development of these components.

  3. Volume Regulation and Renal Function at High Altitude across Gender

    PubMed Central

    Haditsch, Bernd; Roessler, Andreas; Krisper, Peter; Frisch, Herwig; Hinghofer-Szalkay, Helmut G.; Goswami, Nandu

    2015-01-01

    Aims We investigated changes in volume regulating hormones and renal function at high altitudes and across gender. Methodology Included in this study were 28 subjects (n = 20 males; n = 8 females. ages: 19 – 65 yrs), who ascended to a height of 3440m (HA1), on the 3rd day and to 5050m (HA2), on the 14th day. Plasma and urinary creatinine and urinary osmolality as well as plasma levels of plasma renin activity (PRA), Aldosterone, antidiuretic hormone (ADH), and atrial natriuretic peptide (ANP) were measured. The plasma volume loss (PVL) was estimated from plasma density and hematocrit. Glomerular filtration rate (GFR) was measured based on nocturnal (9 hour) creatinine clearance; this was compared with various methods for estimation of GFR. Results The mean 24-hour urine production increased significantly in both sexes across the expedition. But PVL reached significance only in males. No changes in Na+ in plasma, urine or its fractional excretion were seen at both altitudes. Urinary osmolality decreased upon ascent to the higher altitudes. ADH and PRA decreased significantly at both altitudes in males but only at HA2 in females. However, no changes in aldosterone were seen across the sexes and at different altitudes. ANP increased significantly only in males during the expedition. GFR, derived from 9-h creatinine clearance (CreaCl), decreased in both sexes at HA1 but remained stable at HA2. Conventional Crea[p]-based GFR estimates (eGFR) showed only poor correlation to CreaCl. Conclusions We report details of changes in hormonal patterns across high altitude sojourn. To our knowledge we are not aware of any study that has examined these hormones in same subjects and across gender during high altitude sojourn. Our results also suggest that depending on the estimation formula used, eGFR underestimated the observed decrease in renal function measured by CreaCl, thus opening the debate regarding the use of estimated glomerular filtration rates at high altitudes. PMID

  4. Energy metabolism and the high-altitude environment.

    PubMed

    Murray, Andrew J

    2016-01-01

    At high altitude the barometric pressure falls, challenging oxygen delivery to the tissues. Thus, whilst hypoxia is not the only physiological stress encountered at high altitude, low arterial P(O2) is a sustained feature, even after allowing adequate time for acclimatization. Cardiac and skeletal muscle energy metabolism is altered in subjects at, or returning from, high altitude. In the heart, energetic reserve falls, as indicated by lower phosphocreatine-to-ATP ratios. The underlying mechanism is unknown, but in the hypoxic rat heart fatty acid oxidation and respiratory capacity are decreased, whilst pyruvate oxidation is also lower after sustained hypoxic exposure. In skeletal muscle, there is not a consensus. With prolonged exposure to extreme high altitude (>5500 m) a loss of muscle mitochondrial density is seen, but this was not observed in a simulated ascent of Everest in hypobaric chambers. At more moderate high altitude, decreased respiratory capacity may occur without changes in mitochondrial volume density, and fat oxidation may be downregulated, although this is not seen in all studies. The underlying mechanisms, including the possible role of hypoxia-signalling pathways, remain to be resolved, particularly in light of confounding factors in the high-altitude environment. In high-altitude-adapted Tibetan natives, however, there is evidence of natural selection centred around the hypoxia-inducible factor pathway, and metabolic features in this population (e.g. low cardiac phosphocreatine-to-ATP ratios, increased cardiac glucose uptake and lower muscle mitochondrial densities) share similarities with those in acclimatized lowlanders, supporting a possible role for the hypoxia-inducible factor pathway in the metabolic response of cardiac and skeletal muscle energy metabolism to high altitude. PMID:26315373

  5. 40 CFR 721.9503 - Silane, (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl)trimethoxy-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Silane, (3,3,4,4,5,5,6,6,7,7,8,8,9,9... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.9503 Silane, (3,3,4,4,5,5,6,6,7,7,8,8... subject to reporting. (1) The chemical substance identified as silane,...

  6. 40 CFR 721.9503 - Silane, (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl)trimethoxy-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Silane, (3,3,4,4,5,5,6,6,7,7,8,8,9,9... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.9503 Silane, (3,3,4,4,5,5,6,6,7,7,8,8... subject to reporting. (1) The chemical substance identified as silane,...

  7. 40 CFR 721.9503 - Silane, (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl)trimethoxy-.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Silane, (3,3,4,4,5,5,6,6,7,7,8,8,9,9... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.9503 Silane, (3,3,4,4,5,5,6,6,7,7,8,8... subject to reporting. (1) The chemical substance identified as silane,...

  8. 40 CFR 721.9503 - Silane, (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl)trimethoxy-.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Silane, (3,3,4,4,5,5,6,6,7,7,8,8,9,9... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.9503 Silane, (3,3,4,4,5,5,6,6,7,7,8,8... subject to reporting. (1) The chemical substance identified as silane,...

  9. 40 CFR 721.9503 - Silane, (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl)trimethoxy-.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Silane, (3,3,4,4,5,5,6,6,7,7,8,8,9,9... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.9503 Silane, (3,3,4,4,5,5,6,6,7,7,8,8... subject to reporting. (1) The chemical substance identified as silane,...

  10. Predator foraging altitudes reveal the structure of aerial insect communities.

    PubMed

    Helms, Jackson A; Godfrey, Aaron P; Ames, Tayna; Bridge, Eli S

    2016-01-01

    The atmosphere is populated by a diverse array of dispersing insects and their predators. We studied aerial insect communities by tracking the foraging altitudes of an avian insectivore, the Purple Martin (Progne subis). By attaching altitude loggers to nesting Purple Martins and collecting prey delivered to their nestlings, we determined the flight altitudes of ants and other insects. We then tested hypotheses relating ant body size and reproductive ecology to flight altitude. Purple Martins flew up to 1,889 meters above ground, and nestling provisioning trips ranged up to 922 meters. Insect communities were structured by body size such that species of all sizes flew near the ground but only light insects flew to the highest altitudes. Ant maximum flight altitudes decreased by 60% from the lightest to the heaviest species. Winged sexuals of social insects (ants, honey bees, and termites) dominated the Purple Martin diet, making up 88% of prey individuals and 45% of prey biomass. By transferring energy from terrestrial to aerial food webs, mating swarms of social insects play a substantial role in aerial ecosystems. Although we focus on Purple Martins and ants, our combined logger and diet method could be applied to a range of aerial organisms. PMID:27352817

  11. VLF waves at satellite altitude to investigate Earth electrical conductivity

    NASA Astrophysics Data System (ADS)

    Leye, P. O.; Tarits, P.

    2015-03-01

    At and near the Earth surface, electromagnetic (EM) fields radiated from VLF transmitters are commonly used in geological exploration to determine the shallow Earth conductivity structure. Onboard satellites such as DEMETER, the electric and magnetic sensors detect the VLF signal in altitude. While we know for surface measurement that the VLF EM field recorded at some distance from the transmitter is a function of the ground conductivity, we do not know how this relationship changes when the field is measured at satellite altitude. Here we study the electromagnetic field radiated by a vertical electric dipole located on the Earth surface in the VLF range and measured at satellite altitude in a free space. We investigate the EM field as function of distance from the source, the height above the Earth surface, and the electrical conductivity of the Earth. The mathematical solution in altitude has more severe numerical complications than the well-known solutions at or near the Earth surface. We test most of the solutions developed for the latter case and found that direct summation was best at several hundred kilometers above the Earth. The numerical modeling of the EM field in altitude shows that the field remains a function of Earth conductivity. The dependence weakens with altitude and distance from the transmitter. It remains more important for the electric radial component.

  12. Wilderness medicine at high altitude: recent developments in the field.

    PubMed

    Shah, Neeraj M; Hussain, Sidra; Cooke, Mark; O'Hara, John P; Mellor, Adrian

    2015-01-01

    Travel to high altitude is increasingly popular. With this comes an increased incidence of high-altitude illness and therefore an increased need to improve our strategies to prevent and accurately diagnose these. In this review, we provide a summary of recent advances of relevance to practitioners who may be advising travelers to altitude. Although the Lake Louise Score is now widely used as a diagnostic tool for acute mountain sickness (AMS), increasing evidence questions the validity of doing so, and of considering AMS as a single condition. Biomarkers, such as brain natriuretic peptide, are likely correlating with pulmonary artery systolic pressure, thus potential markers of the development of altitude illness. Established drug treatments include acetazolamide, nifedipine, and dexamethasone. Drugs with a potential to reduce the risk of developing AMS include nitrate supplements, propagators of nitric oxide, and supplemental iron. The role of exercise in the development of altitude illness remains hotly debated, and it appears that the intensity of exercise is more important than the exercise itself. Finally, despite copious studies demonstrating the value of preacclimatization in reducing the risk of altitude illness and improving performance, an optimal protocol to preacclimatize an individual remains elusive. PMID:26445563

  13. Wilderness medicine at high altitude: recent developments in the field

    PubMed Central

    Shah, Neeraj M; Hussain, Sidra; Cooke, Mark; O’Hara, John P; Mellor, Adrian

    2015-01-01

    Travel to high altitude is increasingly popular. With this comes an increased incidence of high-altitude illness and therefore an increased need to improve our strategies to prevent and accurately diagnose these. In this review, we provide a summary of recent advances of relevance to practitioners who may be advising travelers to altitude. Although the Lake Louise Score is now widely used as a diagnostic tool for acute mountain sickness (AMS), increasing evidence questions the validity of doing so, and of considering AMS as a single condition. Biomarkers, such as brain natriuretic peptide, are likely correlating with pulmonary artery systolic pressure, thus potential markers of the development of altitude illness. Established drug treatments include acetazolamide, nifedipine, and dexamethasone. Drugs with a potential to reduce the risk of developing AMS include nitrate supplements, propagators of nitric oxide, and supplemental iron. The role of exercise in the development of altitude illness remains hotly debated, and it appears that the intensity of exercise is more important than the exercise itself. Finally, despite copious studies demonstrating the value of preacclimatization in reducing the risk of altitude illness and improving performance, an optimal protocol to preacclimatize an individual remains elusive. PMID:26445563

  14. Prior altitude experience of climbers attempting to summit Aconcagua.

    PubMed

    Borm, Nicholas; Van Roo, Jon D; Pesce, Carlos; Courtney, D Mark; Malik, Sanjeev; Lazio, Matthew P

    2011-01-01

    Aconcagua (6962 m) is one of the seven summits and the highest mountain outside of Asia. Climbers of varying experience are drawn to its nontechnical route. Our objective was to detail the prior altitude experience of climbers attempting to summit Aconcagua. We asked all climbers on the normal route of Aconcagua to complete questionnaires with demographics and prior high altitude experience while acclimatizing at Plaza de Mulas base camp during 9 nonconsecutive days in January 2009. 127 volunteers from 22 countries were enrolled. Mean age was 39.8 years and 88.2% were male. Median altitude at place of residence was 200 m (IQR: 30, 700). Median previous maximum altitude reached was 5895 m (IQR: 5365, 6150). 7.1% of climbers had never been above 4000 m. Median previous maximum sleeping altitude was 4800 m (IQR: 4300, 5486). 12.6% of climbers had never slept above 4000 m. Climbers who performed acclimatization treks spent a mean of 3.6 (2.5, 4.7) days at>3000 m in the previous 2 months. However, 50.4% of climbers performed no acclimatization treks. Although the majority of mountaineers who attempt Aconcagua have prior high altitude experience, a substantial minority has never been above 4000 m. PMID:22206564

  15. Convergent Evolution of Rumen Microbiomes in High-Altitude Mammals.

    PubMed

    Zhang, Zhigang; Xu, Dongming; Wang, Li; Hao, Junjun; Wang, Jinfeng; Zhou, Xin; Wang, Weiwei; Qiu, Qiang; Huang, Xiaodan; Zhou, Jianwei; Long, Ruijun; Zhao, Fangqing; Shi, Peng

    2016-07-25

    Studies of genetic adaptation, a central focus of evolutionary biology, most often focus on the host's genome and only rarely on its co-evolved microbiome. The Qinghai-Tibetan Plateau (QTP) offers one of the most extreme environments for the survival of human and other mammalian species. Yaks (Bos grunniens) and Tibetan sheep (T-sheep) (Ovis aries) have adaptations for living in this harsh high-altitude environment, where nomadic Tibetan people keep them primarily for food and livelihood [1]. Adaptive evolution affects energy-metabolism-related genes in a way that helps these ruminants live at high altitude [2, 3]. Herein, we report convergent evolution of rumen microbiomes for energy harvesting persistence in two typical high-altitude ruminants, yaks and T-sheep. Both ruminants yield significantly lower levels of methane and higher yields of volatile fatty acids (VFAs) than their low-altitude relatives, cattle (Bos taurus) and ordinary sheep (Ovis aries). Ultra-deep metagenomic sequencing reveals significant enrichment in VFA-yielding pathways of rumen microbial genes in high-altitude ruminants, whereas methanogenesis pathways show enrichment in the cattle metagenome. Analyses of RNA transcriptomes reveal significant upregulation in 36 genes associated with VFA transport and absorption in the ruminal epithelium of high-altitude ruminants. Our study provides novel insights into the contributions of microbiomes to adaptive evolution in mammals and sheds light on the biological control of greenhouse gas emissions from livestock enteric fermentation. PMID:27321997

  16. Predator foraging altitudes reveal the structure of aerial insect communities

    PubMed Central

    Helms, Jackson A.; Godfrey, Aaron P.; Ames, Tayna; Bridge, Eli S.

    2016-01-01

    The atmosphere is populated by a diverse array of dispersing insects and their predators. We studied aerial insect communities by tracking the foraging altitudes of an avian insectivore, the Purple Martin (Progne subis). By attaching altitude loggers to nesting Purple Martins and collecting prey delivered to their nestlings, we determined the flight altitudes of ants and other insects. We then tested hypotheses relating ant body size and reproductive ecology to flight altitude. Purple Martins flew up to 1,889 meters above ground, and nestling provisioning trips ranged up to 922 meters. Insect communities were structured by body size such that species of all sizes flew near the ground but only light insects flew to the highest altitudes. Ant maximum flight altitudes decreased by 60% from the lightest to the heaviest species. Winged sexuals of social insects (ants, honey bees, and termites) dominated the Purple Martin diet, making up 88% of prey individuals and 45% of prey biomass. By transferring energy from terrestrial to aerial food webs, mating swarms of social insects play a substantial role in aerial ecosystems. Although we focus on Purple Martins and ants, our combined logger and diet method could be applied to a range of aerial organisms. PMID:27352817

  17. Focusing Cosmic Telescopes: Exploring Redshift z ~ 5-6 Galaxies with the Bullet Cluster 1E0657 - 56

    NASA Astrophysics Data System (ADS)

    Bradač, Maruša; Treu, Tommaso; Applegate, Douglas; Gonzalez, Anthony H.; Clowe, Douglas; Forman, William; Jones, Christine; Marshall, Phil; Schneider, Peter; Zaritsky, Dennis

    2009-12-01

    The gravitational potential of clusters of galaxies acts as a cosmic telescope allowing us to find and study galaxies at fainter limits than otherwise possible and thus probe closer to the epoch of formation of the first galaxies. We use the Bullet cluster 1E0657 - 56 (z = 0.296) as a case study, because its high mass and merging configuration makes it one of the most efficient cosmic telescopes we know. We develop a new algorithm to reconstruct the gravitational potential of the Bullet cluster based on a non-uniform adaptive grid, combining strong and weak gravitational lensing data derived from deep Hubble Space Telescope/Advanced Camera for Surveys F606W-F775W-F850LP and ground-based imaging. We exploit this improved mass map to study z ~ 5-6 Lyman break galaxies (LBGs), which we detect as dropouts. One of the LBGs is multiply imaged, providing a geometric confirmation of its high redshift, and is used to further improve our mass model. We quantify the uncertainties in the magnification map reconstruction in the intrinsic source luminosity, and in the volume surveyed, and show that they are negligible compared to sample variance when determining the luminosity function of high-redshift galaxies. With shallower and comparable magnitude limits to Hubble Ultra Deep Field (HUDF) and Great Observatories Origins Deep Survey (GOODS), the Bullet cluster observations, after correcting for magnification, probe deeper into the luminosity function of the high-redshift galaxies than GOODS and only slightly shallower than HUDF. We conclude that accurately focused cosmic telescopes are the most efficient way to sample the bright end of the luminosity function of high-redshift galaxies and—in case they are multiply imaged—confirm their redshifts. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5

  18. Emerging toxicity of 5,6-methylenedioxy-2-aminoindane (MDAI): Pharmacokinetics, behaviour, thermoregulation and LD50 in rats.

    PubMed

    Páleníček, Tomáš; Lhotková, Eva; Žídková, Monika; Balíková, Marie; Kuchař, Martin; Himl, Michal; Mikšátková, Petra; Čegan, Martin; Valeš, Karel; Tylš, Filip; Horsley, Rachel R

    2016-08-01

    MDAI (5,6-Methylenedioxy-2-aminoindane) has a reputation as a non-neurotoxic ecstasy replacement amongst recreational users, however the drug has been implicated in some severe and lethal intoxications. Due to this, and the fact that the drug is almost unexplored scientifically we investigated a broad range of effects of acute MDAI administration: pharmacokinetics (in sera, brain, liver and lung); behaviour (open field; prepulse inhibition, PPI); acute effects on thermoregulation (in group-/individually-housed rats); and systemic toxicity (median lethal dose, LD50) in Wistar rats. Pharmacokinetics of MDAI was rapid, maximum median concentration in serum and brain was attained 30min and almost returned to zero 6h after subcutaneous (sc.) administration of 10mg/kg MDAI; brain/serum ratio was ~4. MDAI particularly accumulated in lung tissue. In the open field, MDAI (5, 10, 20 and 40mg/kg sc.) increased exploratory activity, induced signs of behavioural serotonin syndrome and reduced locomotor habituation, although by 60min some effects had diminished. All doses of MDAI significantly disrupted PPI and the effect was present during the onset of its action as well as 60min after treatment. Unexpectedly, 40mg/kg MDAI killed 90% of animals in the first behavioural test, hence LD50 tests were conducted which yielded 28.33mg/kg sc. and 35mg/kg intravenous but was not established up to 40mg/kg after gastric administration. Disseminated intravascular coagulopathy (DIC) with brain oedema was concluded as a direct cause of death in sc. treated animals. Finally, MDAI (10, 20mg/kg sc.) caused hyperthermia and perspiration in group-housed rats. In conclusion, the drug had fast pharmacokinetics and accumulated in lipohilic tissues. Behavioural findings were consistent with mild, transient stimulation with anxiolysis and disruption of sensorimotor processing. Together with hyperthermia, the drug had a similar profile to related entactogens, especially 3

  19. Mesoscale simulations of the November 25-26 and December 5-6 cirrus cases using the RAMS model

    NASA Technical Reports Server (NTRS)

    Harrington, J. L.; Meyers, Michael P.; Cotton, William R.

    1993-01-01

    The Regional Atmospheric Modeling System (RAMS), developed at Colorado State University, was used during the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment (FIRE) 2 (13 Nov. through 6 Dec. 1991) to provide real time forecasts of cirrus clouds. Forecasts were run once a day, initializing with the 0000 UTC dataset provided by NOAA (Forecast Systems Laboratory (FSL) Mesoscale Analysis and Prediction System (MAPS)). In order to obtain better agreement with observations, a second set of simulations were done for the FIRE 2 cases that occurred on 25-26 Nov. and 5-6 Dec. In this set of simulations, a more complex radiation scheme was used, the Chen/Cotton radiation scheme, along with the nucleation of ice occurring at ice supersaturations as opposed to nucleation occurring at water supersaturations that was done in the actual forecast version. The runs using these more complex schemes took longer wall clock time (7-9 hours for the actual forecasts as compared to 12-14 hrs for the runs using the more complex schemes) however, the final results of the simulations were definitely improved upon. Comparisons between these two sets of simulations are given. Now underway are simulations of these cases using a closed analytical solution for the auto-conversion of ice from a pristine ice class (sizes less than about 50 microns in effective diameter) to a snow class (effective diameters on the order of several hundred microns). This solution is employed along with a new scheme for the nucleation of ice crystals due to Meyers et al and Demott et al. The scheme is derived assuming complete gamma distributions for both the pristine and snow classes. The time rate of change of the number concentration and mass mixing-ratio of each distribution is found by calculating either the flux of crystals that grow beyond a certain critical diameter by vapor deposition in an ice supersaturated regime or by calculating the flux of crystals that evaporate to

  20. Pharmacokinetics and metabolism of triclopyr 3,5,6-trichloro-2-pyridinyloxyacetic acid) in Fischer 344 rats.

    PubMed

    Timchalk, C; Dryzga, M D; Kastl, P E

    1990-05-14

    Triclopyr, (3,5,6-trichloro-2-pyridinyloxyacetic acid) is the active component of GARLON (trademark of the Dow Chemical Company) brand herbicide. [14C]Triclopyr was administered orally to groups of 5 rats/sex as a single 3 and 60 mg/kg body weight dose and as a multiple 3 mg/kg nonradiolabeled dose for 14 days followed by a single 3 mg [14C]triclopyr/kg dose on day 15. A fourth group (5 rats/sex) was administered a single 3 mg/kg intravenous dose of [14C]triclopyr. In addition, two groups of male rats (3/dose) were used to obtain 14C plasma time-course data and were orally administered [14C]triclopyr at doses of 3 and 60 mg/kg. Between 94 and 97% of the administered radioactivity was recovered, and the principal route of excretion was the urine (89-95%). The feces contained less than 3% of the dose and the expired 14CO2 and cage wash accounted for less than 0.2 and 1% of the dose, respectively. The tissues and carcass accounted for less than 2% of the radioactivity at 72 h post-dosing. [14C]Triclopyr was rapidly and completely absorbed after oral administration of 3 and 60 mg/kg. The radioactivity was cleared from the plasma of male rats at 3 mg/kg in a mono-exponential manner, with an apparent first-order elimination half-life of 3.6 h. The primary difference between the 3 and 60 mg/kg dose kinetics was the saturation of renal elimination of triclopyr through 9 h post-dosing for the 60 mg/kg group. [14C]Triclopyr was primarily excreted unchanged in the urine (81-96% of the urinary radioactivity), although 4 minor urinary metabolites were noted. Aside from the initial saturation of renal elimination of triclopyr at 60 mg/kg, there were no appreciable differences in the absorption, disposition, or metabolism of [14C]triclopyr, based on sex, or prior exposure. PMID:2343458