Science.gov

Sample records for aes-2006 protective envelope

  1. Adaptive envelope protection methods for aircraft

    NASA Astrophysics Data System (ADS)

    Unnikrishnan, Suraj

    Carefree handling refers to the ability of a pilot to operate an aircraft without the need to continuously monitor aircraft operating limits. At the heart of all carefree handling or maneuvering systems, also referred to as envelope protection systems, are algorithms and methods for predicting future limit violations. Recently, envelope protection methods that have gained more acceptance, translate limit proximity information to its equivalent in the control channel. Envelope protection algorithms either use very small prediction horizon or are static methods with no capability to adapt to changes in system configurations. Adaptive approaches maximizing prediction horizon such as dynamic trim, are only applicable to steady-state-response critical limit parameters. In this thesis, a new adaptive envelope protection method is developed that is applicable to steady-state and transient response critical limit parameters. The approach is based upon devising the most aggressive optimal control profile to the limit boundary and using it to compute control limits. Pilot-in-the-loop evaluations of the proposed approach are conducted at the Georgia Tech Carefree Maneuver lab for transient longitudinal hub moment limit protection. Carefree maneuvering is the dual of carefree handling in the realm of autonomous Uninhabited Aerial Vehicles (UAVs). Designing a flight control system to fully and effectively utilize the operational flight envelope is very difficult. With the increasing role and demands for extreme maneuverability there is a need for developing envelope protection methods for autonomous UAVs. In this thesis, a full-authority automatic envelope protection method is proposed for limit protection in UAVs. The approach uses adaptive estimate of limit parameter dynamics and finite-time horizon predictions to detect impending limit boundary violations. Limit violations are prevented by treating the limit boundary as an obstacle and by correcting nominal control

  2. Envelope Protection and Recovery Guidance for Upset Conditions

    NASA Technical Reports Server (NTRS)

    Lombaerts, Thomas; Schuet, Stefan; Acosta, Diana; Kaneshige, John; Shish, Kim

    2016-01-01

    The slides are an overview and summary of past and current research projects in the field of envelope protection, upset prevention and upset recovery, with the aim to avoid loss of control accidents and improve safety in air transportation.

  3. Envelope Protection for In-Flight Ice Contamination

    NASA Technical Reports Server (NTRS)

    Gingras, David R.; Barnhart, Billy P.; Ranaudo, Richard J.; Ratvasky, Thomas P.; Morelli, Eugene A.

    2010-01-01

    Fatal loss-of-control (LOC) accidents have been directly related to in-flight airframe icing. The prototype system presented in this paper directly addresses the need for real-time onboard envelope protection in icing conditions. The combinations of a-priori information and realtime aerodynamic estimations are shown to provide sufficient input for determining safe limits of the flight envelope during in-flight icing encounters. The Icing Contamination Envelope Protection (ICEPro) system has been designed and implemented to identify degradations in airplane performance and flying qualities resulting from ice contamination and provide safe flight-envelope cues to the pilot. Components of ICEPro are described and results from preliminary tests are presented.

  4. 78 FR 19981 - Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection: High Speed...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-03

    ...; Flight Envelope Protection: High Speed Limiting AGENCY: Federal Aviation Administration (FAA), DOT... 11562). The document issued special conditions pertaining flight envelope protection: high...

  5. Methodologies for Adaptive Flight Envelope Estimation and Protection

    NASA Technical Reports Server (NTRS)

    Tang, Liang; Roemer, Michael; Ge, Jianhua; Crassidis, Agamemnon; Prasad, J. V. R.; Belcastro, Christine

    2009-01-01

    This paper reports the latest development of several techniques for adaptive flight envelope estimation and protection system for aircraft under damage upset conditions. Through the integration of advanced fault detection algorithms, real-time system identification of the damage/faulted aircraft and flight envelop estimation, real-time decision support can be executed autonomously for improving damage tolerance and flight recoverability. Particularly, a bank of adaptive nonlinear fault detection and isolation estimators were developed for flight control actuator faults; a real-time system identification method was developed for assessing the dynamics and performance limitation of impaired aircraft; online learning neural networks were used to approximate selected aircraft dynamics which were then inverted to estimate command margins. As off-line training of network weights is not required, the method has the advantage of adapting to varying flight conditions and different vehicle configurations. The key benefit of the envelope estimation and protection system is that it allows the aircraft to fly close to its limit boundary by constantly updating the controller command limits during flight. The developed techniques were demonstrated on NASA s Generic Transport Model (GTM) simulation environments with simulated actuator faults. Simulation results and remarks on future work are presented.

  6. Envelope protection systems for piloted and unmanned rotorcraft

    NASA Astrophysics Data System (ADS)

    Sahani, Nilesh A.

    Performance and agility of rotorcraft can be improved using envelope protection systems (or carefree maneuvering systems), which allow the aircraft to use the full flight envelope without risk of exceeding structural or controllability limits. Implementation of such a system can be divided into two necessary parts: "Limit Prediction" which detects the impending violation of the limit parameter, and "Limit Avoidance" where a preventive action is taken in the form of pilot cueing or autonomous limiting. Depending upon the underlying flight control system, implementation of the envelope limiting system was categorized into two different structures: "Inceptor Constraint Architecture" and "Command Limiting Architecture". The Inceptor Constraint Architecture is applicable to existing rotorcraft with conventional flight control system where control input proportionally affects control surfaces. The relationship between control input and limit parameter is complex which requires advanced algorithms for predicting impending limit violations. This research focuses on limits that exceed in transient response. A new algorithm was developed for predicting transient response using non-linear functions of measured aircraft states. The functions were generated off-line using simulation data from a non-real-time simulation, model to demonstrate the procedure for extracting them from flight test data. Modern rotorcraft flight control systems are designed to accurately track certain aircraft states like roll and pitch attitudes which are either specified as command inputs in unmanned rotorcraft or mapped to control stick in piloted aircrafts. In the Command Limiting Architecture applicable to these systems, performance constraints were generated on the command input corresponding to the envelope limit. To simulate this flight control system, an adaptive model inversion controller was applied to a non-linear, blade element simulation model of a helicopter. The controller generated

  7. Dengue Type-2 Virus Envelope Protein Made Using Recombinant Baculovirus Protects Mice Against Virus Challenge

    DTIC Science & Technology

    1994-01-01

    the envelope (E) glycoprotein of dengue 2 virus was cloned into baculovirus (IAutographa californical nuclear polyhedrosis virus, AcNPV). The...polyclonal, anti- dengue type 2 antibody and a dengue type 2-specific, neutralizing monoclonal antibody. Balb/c mice immunized with the recombinant...antigen produced only non-neutralizing antibody against dengue 2 virus but were partially protected against morbidity and mortality after

  8. 78 FR 31838 - Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection: General...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-28

    ... new control architecture and a full digital flight control system which provides flight envelope... flight envelope protection features integral to the electronic flight control system design. These flight...) occurs in the control laws of the electronic flight control system as the limit is approached or...

  9. A chimeric measles virus with canine distemper envelope protects ferrets from lethal distemper challenge.

    PubMed

    Rouxel, Ronan Nicolas; Svitek, Nicholas; von Messling, Veronika

    2009-08-06

    CDV infects a broad range of carnivores, and over the past decades it has caused outbreaks in a variety of wild carnivore populations. Since the currently available live-attenuated vaccine is not sufficiently safe in these highly susceptible species, we produced a chimeric virus combining the replication complex of the measles Moraten vaccine strain with the envelope of a recent CDV wild type isolate. The resulting virus did not cause disease or immunosuppression in ferrets and conferred protection from challenge with a lethal wild type strain, demonstrating its potential value for wildlife conservation efforts.

  10. Development and Implementation of a Model-Driven Envelope Protection System for In-Flight Ice Contamination

    NASA Technical Reports Server (NTRS)

    Gingras, David R.; Barnhart, Billy P.; Martos, Borja; Ratvasky, Thomas P.; Morelli, Eugene

    2011-01-01

    Fatal loss-of-control (LOC) accidents have been directly related to in-flight airframe icing. The prototype system presented in this paper directly addresses the need for real-time onboard envelope protection in icing conditions. The combinations of a-priori information and realtime aerodynamic estimations are shown to provide sufficient input for determining safe limits of the flight envelope during in-flight icing encounters. The Icing Contamination Envelope Protection (ICEPro) system has been designed and implemented to identify degradations in airplane performance and flying qualities resulting from ice contamination and provide safe flight-envelope cues to the pilot. Components of ICEPro are described and results from preliminary tests are presented.

  11. 78 FR 11562 - Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection: High Speed...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-19

    ...These special conditions are issued for the Embraer S.A. Model EMB-550 airplane. This airplane will have a novel or unusual design feature, specifically an electronic flight control system which contains fly-by-wire control laws, including envelope protections, for the overspeed protection and roll limiting function. The applicable airworthiness regulations do not contain adequate or......

  12. Vaccinia Virus Extracellular Enveloped Virion Neutralization In Vitro and Protection In Vivo Depend on Complement▿

    PubMed Central

    Benhnia, Mohammed Rafii-El-Idrissi; McCausland, Megan M.; Moyron, Juan; Laudenslager, John; Granger, Steven; Rickert, Sandra; Koriazova, Lilia; Kubo, Ralph; Kato, Shinichiro; Crotty, Shane

    2009-01-01

    Antibody neutralization is an important component of protective immunity against vaccinia virus (VACV). Two distinct virion forms, mature virion and enveloped virion (MV and EV, respectively), possess separate functions and nonoverlapping immunological properties. In this study we examined the mechanics of EV neutralization, focusing on EV protein B5 (also called B5R). We show that neutralization of EV is predominantly complement dependent. From a panel of high-affinity anti-B5 monoclonal antibodies (MAbs), the only potent neutralizer in vitro (90% at 535 ng/ml) was an immunoglobulin G2a (IgG2a), and neutralization was complement mediated. This MAb was the most protective in vivo against lethal intranasal VACV challenge. Further studies demonstrated that in vivo depletion of complement caused a >50% loss of anti-B5 IgG2a protection, directly establishing the importance of complement for protection against the EV form. However, the mechanism of protection is not sterilizing immunity via elimination of the inoculum as the viral inoculum consisted of a purified MV form. The prevention of illness in vivo indicated rapid control of infection. We further demonstrate that antibody-mediated killing of VACV-infected cells expressing surface B5 is a second protective mechanism provided by complement-fixing anti-B5 IgG. Cell killing was very efficient, and this effector function was highly isotype specific. These results indicate that anti-B5 antibody-directed cell lysis via complement is a powerful mechanism for clearance of infected cells, keeping poxvirus-infected cells from being invisible to humoral immune responses. These findings highlight the importance of multiple mechanisms of antibody-mediated protection against VACV and point to key immunobiological differences between MVs and EVs that impact the outcome of infection. PMID:19019965

  13. 78 FR 5148 - Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection: General...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-24

    ...(s), specifically new control architecture and a full digital flight control system which provides... flight envelope protection features integral to the electronic flight control system design. These flight...) occurs in the control laws of the electronic flight control system as the limit is approached or...

  14. Condensation heat transfer of pure steam and steam from gas-steam mixture in tubes of AES-2006 PHRS SG heat exchanger

    NASA Astrophysics Data System (ADS)

    Balunov, B. F.; Il'in, V. A.; Shcheglov, A. A.; Lychakov, V. D.; Alekseev, S. B.; Kuhtevich, V. O.; Svetlov, S. V.; Sidorov, V. G.

    2017-01-01

    Results of experimental determination of the average heat transfer coefficient upon condensation of pure steam αc and steam from air-steam mixture αas.m in tubes of a large-scale model of the emergency cooling heat exchanger in the system of passive heat removal through steam generators of AES-2006 project at Leningrad II NPP are presented. The model contained 16 parallel tubes with a diameter of 16 × 2 mm and a length of 2.9 m connected to the upper steam distributing and lower condensate gathering horizontal collectors; the distance between their axes was 2.28 m. The tube segments were vertical, horizontal, or inclined. The internal diameter of the collectors was 40 or 60 mm. The model was placed in the lower part of a tank with a height of 6.5 m and a volume of 5.85 m3 filled with boiling water at atmospheric pressure. The experimental parameters were as follows: pressure range 0.43-7.77 MPa, condensate Reynolds number Ref = (0.87-9.3) × 103, and average air volume fraction at the segment with air-steam mixture 0.18-0.85. The studies showed that nonuniformity of static pressure distribution along the steam-distributing collector strongly influences the reduction of αc value (ejecting effect). The agreement between experimental and calculated according to statutory guidelines values of αc for vertical tubes is achieved if the dynamic head of the steam flow at the input of the steam-distributing collector does not exceed 1 kPa. Equations for calculation of the diffusion heat transfer coefficient at steam condensation from the air-steam mixture αas.m on the internal tube surface are proposed. In the considered conditions, air is completely displaced by steam flow from the upper to the lower part of the tubes. The boundary between these regions is characterized by an average reduced steam velocity through this cross section of 1.6 ± 0.4 m/s. Above the boundary cross section, it is recommended to calculate αc. according to [1].

  15. A recombinant pseudotyped lentivirus expressing the envelope glycoprotein of Hantaan virus induced protective immunity in mice

    PubMed Central

    2013-01-01

    Background Hantaviruses cause acute hemorrhagic fever with renal syndrome (HFRS). Currently, several types of inactivated HFRS vaccines are widely used, however the limited ability of these immunogen to elicit neutralizing antibodies restricts vaccine efficacy. Development of an effective vaccine to overcome this weakness is must. Methods In the present study, a recombinant pseudotyped lentivirus bearing the hantaan virus (HTNV) envelope glycoproteins (GP), rLV-M, was constructed. C57BL/6 mice were immunized with the rLV-M and a series of immunological assays were conducted to determine the immunogenicity of the recombinant pseudotyped lentivirus. The humoral and cell-mediated immune responses induced by rLV-M were compared with those of the inactivated HFRS vaccine. Results Indirect immunofluorescence assay (IFA) showed the rLV-M expressed target proteins in HEK-293cells. In mice, the rLV-M efficiently induced GP-specific humoral responses and protection against HTNV infection. Furthermore, the rLV-M induced higher neutralizing antibody titers than the inactivated HFRS vaccine control. Conclusions The results indicated the potential of using a pseudotyped lentivirus as a delivery vector for a hantavirus vaccine immunogen. PMID:24093752

  16. Structural Organization of Baculovirus Occlusion Bodies and Protective Role of Multilayered Polyhedron Envelope Protein.

    PubMed

    Sajjan, Dayanand B; Hinchigeri, Shivayogeppa B

    2016-03-01

    Baculoviruses are the ingenious insect pathogens. Outside the host, baculovirus occlusion bodies (OB) provide stability to occlusion-derived viruses (ODV) embedded within. The OB is an organized structure, chiefly composed of proteins namely polyhedrin, polyhedron envelope protein (PEP) and P10. Currently, the structural organization of OB is poorly understood and the role of OB proteins in conferring the stability to ODV is unknown. Here we have shown that the assembly of polyhedrin unit cells into an OB is a rapid process; the PEP forms in multiple layers; the PEP layers predominantly contribute to ODV viability. Full-grown OBs (n = 36) were found to be 4.0 ± 1.0 µm in diameter and possessed a peculiar geometry of a truncated rhombic dodecahedron. The atomic force microscopy (AFM) study on the structure of OBs at different stages of growth in insect cells revealed polyhedrin assembly and thickness of PEP layers. The thickness of PEP layers at 53 h post-transfection (hpt) ranged from 56 to 80 nm. Mature PEP layers filled up approximately one third of the OB volume. The size of ODV nucleocapsid was found to be 433 ± 10 nm in length. The zeta potential and particle size distribution study of viruses revealed the protective role of PEP layers. The presence of a multilayered PEP confers a viable advantage to the baculoviruses compared to single-layered PEP. Thus, these findings may help in developing PEP layer-based biopolymers for protein-based nanodevices, nanoelectrodes and more stable biopesticides.

  17. Is obesity protective against wound healing complications in pilon surgery? Soft tissue envelope and pilon fractures in the obese.

    PubMed

    Graves, Matthew L; Porter, Scott E; Fagan, Bryan C; Brien, Glenn A; Lewis, Matthew W; Biggers, Marcus D; Woodall, James R; Russell, George V

    2010-08-11

    Open treatment of pilon fractures is associated with wound healing complications. A traumatized, limited soft tissue envelope contributes to wound healing complications. Obese patients have larger soft tissue envelopes around the ankle, theoretically providing a greater area for energy distribution and more accommodation to implants. This led us to test 2 hypotheses: (1) ankle dimensions in obese patients are larger than in lean patients, and (2) the increased soft tissue envelope volume translates into fewer wound complications. A consecutive series of 176 pilon fractures treated from March 2002 to December 2007 were retrospectively reviewed. Inclusion criteria were adults who received a preoperative computed tomography (CT) scan and were treated with a staged protocol including plating. Patients with body mass index (BMI) >30 were compared to those with BMI <30 for CT-derived ankle dimensions and wound complications. Comorbidities were evaluated for their role as potential confounders. Thirty-one fractures in obese patients were compared to 83 in lean patients. The average ratio of bone area to soft tissue area at the tibial plafond was 0.35 for the obese group and 0.38 for the lean group (P=.012). There were 8 major wound-healing complications. Four occurred in the obese group (incidence 13%), and 4 in the lean group (incidence 5%) (P=.252). Ankle dimensions in clinically obese patients are larger than in lean patients. Obesity does not appear to be protective of wound-healing complications, but rather there is a trend toward the opposite.

  18. Protecting from Envelope Stress: Variations on the Phage-Shock-Protein Theme.

    PubMed

    Manganelli, Riccardo; Gennaro, Maria Laura

    2017-03-01

    During envelope stress, critical inner-membrane functions are preserved by the phage-shock-protein (Psp) system, a stress response that emerged from work with Escherichia coli and other Gram-negative bacteria. Reciprocal regulatory interactions and multiple effector functions are well documented in these organisms. Searches for the Psp system across phyla reveal conservation of only one protein, PspA. However, examination of Firmicutes and Actinobacteria reveals that PspA orthologs associate with non-orthologous regulatory and effector proteins retaining functions similar to those in Gram-negative counterparts. Conservation across phyla emphasizes the long-standing importance of the Psp system in prokaryotes, while inter- and intra-phyla variations within the system indicate adaptation to different cell envelope structures, bacterial lifestyles, and/or bacterial morphogenetic strategies.

  19. Neutralizing antibodies to HIV-1 envelope protect more effectively in vivo than those to the CD4 receptor

    PubMed Central

    Pegu, Amarendra; Yang, Zhi-yong; Boyington, Jeffrey C.; Wu, Lan; Ko, Sung-Youl; Schmidt, Stephen D.; McKee, Krisha; Kong, Wing-Pui; Shi, Wei; Chen, Xuejun; Todd, John-Paul; Huang, Jinghe; Nason, Martha C.; Hoxie, James A.; Kwong, Peter D.; Connors, Mark; Rao, Srinivas S.; Mascola, John R.; Nabel, Gary J.

    2015-01-01

    HIV-1 infection depends on effective viral entry mediated by the interaction of its envelope (Env) glycoprotein with specific cell surface receptors. Protective antiviral antibodies generated by passive or active immunization must prevent these interactions. Because the HIV-1 Env is highly variable, attention has also focused on blocking the HIV-1 primary cell receptor CD4. We therefore analyzed the in vivo protective efficacy of three potent neutralizing monoclonal antibodies (mAbs) to HIV-1 Env compared to an antibody against the CD4 receptor. Protection was assessed after mucosal challenge of rhesus macaques with simian/HIV (SHIV). Despite its comparable or greater neutralization potency in vitro, the anti-CD4 antibody did not provide effective protection in vivo, whereas the HIV-1–specific mAbs VRC01, 10E8, and PG9, targeting the CD4 binding site, membrane-proximal, and V1V2 glycan Env regions, respectively, conferred complete protection, albeit at different relative potencies. These findings demonstrate the protective efficacy of broadly neutralizing antibodies directed to the HIV-1 Env and suggest that targeting the HIV-1 Env is preferable to the cell surface receptor CD4 for the prevention of HIV-1 transmission. PMID:24990883

  20. Piloted Simulation to Evaluate the Utility of a Real Time Envelope Protection System for Mitigating In-Flight Icing Hazards

    NASA Technical Reports Server (NTRS)

    Ranaudo, Richard J.; Martos, Borja; Norton, Bill W.; Gingras, David R.; Barnhart, Billy P.; Ratvasky, Thomas P.; Morelli, Eugene

    2011-01-01

    The utility of the Icing Contamination Envelope Protection (ICEPro) system for mitigating a potentially hazardous icing condition was evaluated by 29 pilots using the NASA Ice Contamination Effects Flight Training Device (ICEFTD). ICEPro provides real time envelope protection cues and alerting messages on pilot displays. The pilots participating in this test were divided into two groups; a control group using baseline displays without ICEPro, and an experimental group using ICEPro driven display cueing. Each group flew identical precision approach and missed approach procedures with a simulated failure case icing condition. Pilot performance, workload, and survey questionnaires were collected for both groups of pilots. Results showed that real time assessment cues were effective in reducing the number of potentially hazardous upset events and in lessening exposure to loss of control following an incipient upset condition. Pilot workload with the added ICEPro displays was not measurably affected, but pilot opinion surveys showed that real time cueing greatly improved their situation awareness of a hazardous aircraft state.

  1. Chimeric porcine reproductive and respiratory syndrome virus containing shuffled multiple envelope genes confers cross-protection in pigs.

    PubMed

    Tian, Debin; Ni, Yan-Yan; Zhou, Lei; Opriessnig, Tanja; Cao, Dianjun; Piñeyro, Pablo; Yugo, Danielle M; Overend, Christopher; Cao, Qian; Lynn Heffron, C; Halbur, Patrick G; Pearce, Douglas S; Calvert, Jay G; Meng, Xiang-Jin

    2015-11-01

    The extensive genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV) strains is a major obstacle for vaccine development. We previously demonstrated that chimeric PRRSVs in which a single envelope gene (ORF3, ORF4, ORF5 or ORF6) was shuffled via DNA shuffling had an improved heterologous cross-neutralizing ability. In this study, we incorporate all of the individually-shuffled envelope genes together in different combinations into an infectious clone backbone of PRRSV MLV Fostera(®) PRRS. Five viable progeny chimeric viruses were rescued, and their growth characteristics were characterized in vitro. In a pilot pig study, two chimeric viruses (FV-SPDS-VR2,FV-SPDS-VR5) were found to induce cross-neutralizing antibodies against heterologous strains. A subsequent vaccination/challenge study in 72 pigs revealed that chimeric virus FV-SPDS-VR2 and parental virus conferred partial cross-protection when challenged with heterologous strains NADC20 or MN184B. The results have important implications for future development of an effective PRRSV vaccine that confers heterologous protection.

  2. Phosphoinositide 3-Kinase Beta Protects Nuclear Envelope Integrity by Controlling RCC1 Localization and Ran Activity

    PubMed Central

    Redondo-Muñoz, Javier; Pérez-García, Vicente; Rodríguez, María J.; Valpuesta, José M.

    2014-01-01

    The nuclear envelope (NE) forms a barrier between the nucleus and the cytosol that preserves genomic integrity. The nuclear lamina and nuclear pore complexes (NPCs) are NE components that regulate nuclear events through interaction with other proteins and DNA. Defects in the nuclear lamina are associated with the development of laminopathies. As cells depleted of phosphoinositide 3-kinase beta (PI3Kβ) showed an aberrant nuclear morphology, we studied the contribution of PI3Kβ to maintenance of NE integrity. pik3cb depletion reduced the nuclear membrane tension, triggered formation of areas of lipid bilayer/lamina discontinuity, and impaired NPC assembly. We show that one mechanism for PI3Kβ regulation of NE/NPC integrity is its association with RCC1 (regulator of chromosome condensation 1), the activator of nuclear Ran GTPase. PI3Kβ controls RCC1 binding to chromatin and, in turn, Ran activation. These findings suggest that PI3Kβ regulates the nuclear envelope through upstream regulation of RCC1 and Ran. PMID:25348717

  3. Immunogenicity and protective efficacy of recombinant Modified Vaccinia virus Ankara candidate vaccines delivering West Nile virus envelope antigens.

    PubMed

    Volz, Asisa; Lim, Stephanie; Kaserer, Martina; Lülf, Anna; Marr, Lisa; Jany, Sylvia; Deeg, Cornelia A; Pijlman, Gorben P; Koraka, Penelope; Osterhaus, Albert D M E; Martina, Byron E; Sutter, Gerd

    2016-04-07

    West Nile virus (WNV) cycles between insects and wild birds, and is transmitted via mosquito vectors to horses and humans, potentially causing severe neuroinvasive disease. Modified Vaccinia virus Ankara (MVA) is an advanced viral vector for developing new recombinant vaccines against infectious diseases and cancer. Here, we generated and evaluated recombinant MVA candidate vaccines that deliver WNV envelope (E) antigens and fulfil all the requirements to proceed to clinical testing in humans. Infections of human and equine cell cultures with recombinant MVA demonstrated efficient synthesis and secretion of WNV envelope proteins in mammalian cells non-permissive for MVA replication. Prime-boost immunizations in BALB/c mice readily induced circulating serum antibodies binding to recombinant WNV E protein and neutralizing WNV in tissue culture infections. Vaccinations in HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-knockout mice elicited WNV E-specific CD8+ T cell responses. Moreover, the MVA-WNV candidate vaccines protected C57BL/6 mice against lineage 1 and lineage 2 WNV infection and induced heterologous neutralizing antibodies. Thus, further studies are warranted to evaluate these recombinant MVA-WNV vaccines in other preclinical models and use them as candidate vaccine in humans.

  4. Structures of the Zika Virus Envelope Protein and Its Complex with a Flavivirus Broadly Protective Antibody.

    PubMed

    Dai, Lianpan; Song, Jian; Lu, Xishan; Deng, Yong-Qiang; Musyoki, Abednego Moki; Cheng, Huijun; Zhang, Yanfang; Yuan, Yuan; Song, Hao; Haywood, Joel; Xiao, Haixia; Yan, Jinghua; Shi, Yi; Qin, Cheng-Feng; Qi, Jianxun; Gao, George F

    2016-05-11

    Zika virus (ZIKV), a mosquito-borne flavivirus, is a current global public health concern. The flavivirus envelope (E) glycoprotein is responsible for virus entry and represents a major target of neutralizing antibodies for other flaviviruses. Here, we report the structures of ZIKV E protein at 2.0 Å and in complex with a flavivirus broadly neutralizing murine antibody 2A10G6 at 3.0 Å. ZIKV-E resembles all the known flavivirus E structures but contains a unique, positively charged patch adjacent to the fusion loop region of the juxtaposed monomer, which may influence host attachment. The ZIKV-E-2A10G6 complex structure reveals antibody recognition of a highly conserved fusion loop. 2A10G6 binds to ZIKV-E with high affinity in vitro and neutralizes currently circulating ZIKV strains in vitro and in mice. The E protein fusion loop epitope represents a potential candidate for therapeutic antibodies against ZIKV.

  5. 78 FR 6195 - Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-30

    ... Protection: Performance Credit for Automatic Takeoff Thrust Control System (ATTCS) During Go-Around AGENCY... design feature associated with the use of an Automatic Takeoff Thrust Control System (ATTCS) during go... system architecture. Embraer S.A. proposed allowing performance credit for this function during...

  6. Dengue Virus Envelope Dimer Epitope Monoclonal Antibodies Isolated from Dengue Patients Are Protective against Zika Virus

    PubMed Central

    Swanstrom, J. A.; Plante, J. A.; Plante, K. S.; Young, E. F.; McGowan, E.; Gallichotte, E. N.; Widman, D. G.; Heise, M. T.; de Silva, A. M.

    2016-01-01

    ABSTRACT Zika virus (ZIKV) is a mosquito-borne flavivirus responsible for thousands of cases of severe fetal malformations and neurological disease since its introduction to Brazil in 2013. Antibodies to flaviviruses can be protective, resulting in lifelong immunity to reinfection by homologous virus. However, cross-reactive antibodies can complicate flavivirus diagnostics and promote more severe disease, as noted after serial dengue virus (DENV) infections. The endemic circulation of DENV in South America and elsewhere raises concerns that preexisting flavivirus immunity may modulate ZIKV disease and transmission potential. Here, we report on the ability of human monoclonal antibodies and immune sera derived from dengue patients to neutralize contemporary epidemic ZIKV strains. We demonstrate that a class of human monoclonal antibodies isolated from DENV patients neutralizes ZIKV in cell culture and is protective in a lethal murine model. We also tested a large panel of convalescent-phase immune sera from humans exposed to primary and repeat DENV infection. Although ZIKV is most closely related to DENV compared to other human-pathogenic flaviviruses, most DENV immune sera (73%) failed to neutralize ZIKV, while others had low (50% effective concentration [EC50], <1:100 serum dilution; 18%) or moderate to high (EC50, >1:100 serum dilution; 9%) levels of cross-neutralizing antibodies. Our results establish that ZIKV and DENV share epitopes that are targeted by neutralizing, protective human antibodies. The availability of potently neutralizing human monoclonal antibodies provides an immunotherapeutic approach to control life-threatening ZIKV infection and also points to the possibility of repurposing DENV vaccines to induce cross-protective immunity to ZIKV. PMID:27435464

  7. Gene-based vaccination with a mismatched envelope protects against simian immunodeficiency virus infection in nonhuman primates.

    PubMed

    Flatz, Lukas; Cheng, Cheng; Wang, Lingshu; Foulds, Kathryn E; Ko, Sung-Youl; Kong, Wing-Pui; Roychoudhuri, Rahul; Shi, Wei; Bao, Saran; Todd, John-Paul; Asmal, Mohammed; Shen, Ling; Donaldson, Mitzi; Schmidt, Stephen D; Gall, Jason G D; Pinschewer, Daniel D; Letvin, Norman L; Rao, Srinivas; Mascola, John R; Roederer, Mario; Nabel, Gary J

    2012-08-01

    The RV144 trial demonstrated that an experimental AIDS vaccine can prevent human immunodeficiency virus type 1 (HIV-1) infection in humans. Because of its limited efficacy, further understanding of the mechanisms of preventive AIDS vaccines remains a priority, and nonhuman primate (NHP) models of lentiviral infection provide an opportunity to define immunogens, vectors, and correlates of immunity. In this study, we show that prime-boost vaccination with a mismatched SIV envelope (Env) gene, derived from simian immunodeficiency virus SIVmac239, prevents infection by SIVsmE660 intrarectally. Analysis of different gene-based prime-boost immunization regimens revealed that recombinant adenovirus type 5 (rAd5) prime followed by replication-defective lymphocytic choriomeningitis virus (rLCMV) boost elicited robust CD4 and CD8 T-cell and humoral immune responses. This vaccine protected against infection after repetitive mucosal challenge with efficacies of 82% per exposure and 62% cumulatively. No effect was seen on viremia in infected vaccinated monkeys compared to controls. Protection correlated with the presence of neutralizing antibodies to the challenge viruses tested in peripheral blood mononuclear cells. These data indicate that a vaccine expressing a mismatched Env gene alone can prevent SIV infection in NHPs and identifies an immune correlate that may guide immunogen selection and immune monitoring for clinical efficacy trials.

  8. Immunogenicity and protective efficacy of recombinant major envelope protein (rH3L) of buffalopox virus in animal models.

    PubMed

    Kumar, Amit; Yogisharadhya, Revanaiah; Venkatesan, Gnanavel; Bhanuprakash, Veerakyathappa; Shivachandra, Sathish Bhadravati

    2016-02-01

    Buffalopox virus, a zoonotic Indian vaccinia-like virus, is responsible for contagious disease affecting mainly buffaloes, cattle and humans. H3L gene, encoding for an immunodominant major envelope protein of intracellular mature virion of orthopoxviruses, is highly conserved and found to elicit neutralizing antibodies. Therefore in the present study, the immunogenicity and protective efficacy of the recombinant H3L protein of buffalopox virus in laboratory animal models has been evaluated. A partial H3L gene encoding for the C-terminal truncated ectodomain of H3L protein (1M to I280) of BPXV-Vij/96 strain was cloned, over-expressed and purified as histidine-tagged fusion protein (50 kDa) from Escherichia coli using Ni-NTA affinity chromatography. The purified rH3L protein was further used for active immunization of guinea pig (250 μg/dose) and adult mice (10 μg and 50 μg/dose) with or without adjuvants (alum, Freund's Complete Adjuvant and CpG). Subsequently, a gradual increase in antigen specific serum IgG as well as neutralizing antibody titres measured by using indirect-ELISA and serum neutralization test respectively, was noted in both guinea pigs and mouse models. Suckling mice immunized passively with anti-H3L serum showed 80% pre-exposure prophylaxis upon challenge with virulent buffalopox virus strain. An indirect-ELISA based on rH3L protein showed no cross-reactivity with hyperimmune sera against sheeppox virus (SPPV), goatpox virus (GTPV), orf virus (ORFV), foot- and- mouth disease virus (FMDV), peste des petits ruminants virus (PPRV) and bluetongue virus (BTV) during the course of study. The study highlights the potential utility of rH3L protein as a safer prophylactic and diagnostic reagent for buffalopox.

  9. Cross-protection against lymphocytic choriomeningitis virus mediated by a CD4+ T-cell clone specific for an envelope glycoprotein epitope of Lassa virus.

    PubMed Central

    La Posta, V J; Auperin, D D; Kamin-Lewis, R; Cole, G A

    1993-01-01

    Recombinant vaccinia virus expressing the Lassa virus (LV) envelope glycoprotein precursor, V-LSGPC, was used to study the basis of LV-induced cross-protective immunity against the closely related arenavirus lymphocytic choriomeningitis virus (LCMV). C3H/HeJ mice primed with V-LSGPC developed neither circulating antibodies nor CD8+ cytotoxic T cells specific for LCMV, yet they resisted a normally lethal LCMV challenge. Spleen cells from such mice gave a proliferative response to LCMV in vitro that was inhibitable by anti-CD4 antibody. Synthetic peptides corresponding to predicted T-cell sites common to the envelope glycoprotein precursor (GP-C) of LV and that of LCMV were used to map the specificity of the proliferative response to an epitope located between amino acids 403 and 417 of LV GP-C. Several CD4+ T-cell clones specific for the 403-417 peptide were isolated and found to produce gamma interferon in response to both the peptide and LCMV. One of these clones, C9, was selected for further study. C9 lysed I-AK-bearing target cells, and when adoptively transferred to C3H/HeJ mice, it was capable of mediating both a peptide-specific delayed hypersensitivity reaction and resistance to lethal LCMV challenge. These collective findings demonstrate, for the first time, that CD4+ T cells can play a major role in arenavirus-specific cross-protective immunity. PMID:7684468

  10. 77 FR 75066 - Special Conditions: Airbus, A350-900 Series Airplane; Flight Envelope Protection (Icing and Non...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-19

    ...-floor system is to increase automatically the thrust on the operating engines under unusual... special conditions are the following: --High incidence protection system: A system that operates directly... incidence protection system operating and the longitudinal control held on its aft stop. --V min :...

  11. Antibodies targeting dengue virus envelope domain III are not required for serotype-specific protection or prevention of enhancement in vivo.

    PubMed

    Williams, Katherine L; Wahala, Wahala M P B; Orozco, Susana; de Silva, Aravinda M; Harris, Eva

    2012-07-20

    The envelope (E) protein of dengue virus (DENV) is composed of three domains (EDI, EDII, EDIII) and is the main target of neutralizing antibodies. Many monoclonal antibodies that bind EDIII strongly neutralize DENV. However in vitro studies indicate that anti-EDIII antibodies contribute little to the neutralizing potency of human DENV-immune serum. In this study, we assess the role of anti-EDIII antibodies in mouse and human DENV-immune serum in neutralizing or enhancing DENV infection in mice. We demonstrate that EDIII-depleted human DENV-immune serum was protective against homologous DENV infection in vivo. Although EDIII-depleted DENV-immune mouse serum demonstrated decreased neutralization potency in vitro, reduced protection in some organs, and enhanced disease in vivo, administration of increased volumes of EDIII-depleted serum abrogated these effects. These data indicate that anti-EDIII antibodies contribute to protection and minimize enhancement when present, but can be replaced by neutralizing antibodies targeting other epitopes on the dengue virion.

  12. 78 FR 14005 - Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection: Pitch and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-04

    ...) part 25 do not specifically relate to flight characteristics associated with fixed attitude limits. Embraer S.A. will implement pitch and roll attitude protection functions through the normal modes of the... Law 92-574, the ``Noise Control Act of 1972.'' The FAA issues special conditions, as defined in 14...

  13. The N-terminal domain of Schmallenberg virus envelope protein Gc is highly immunogenic and can provide protection from infection.

    PubMed

    Wernike, Kerstin; Aebischer, Andrea; Roman-Sosa, Gleyder; Beer, Martin

    2017-02-13

    Schmallenberg virus (SBV) is transmitted by insect vectors, and therefore vaccination is one of the most important tools of disease control. In our study, novel subunit vaccines on the basis of an amino-terminal domain of SBV Gc of 234 amino acids ("Gc Amino") first were tested and selected using a lethal small animal challenge model and then the best performing formulations also were tested in cattle. We could show that neither E. coli expressed nor the reduced form of "Gc Amino" protected from SBV infection. In contrast, both, immunization with "Gc Amino"-encoding DNA plasmids and "Gc-amino" expressed in a mammalian system, conferred protection in up to 66% of the animals. Interestingly, the best performance was achieved with a multivalent antigen containing the covalently linked Gc domains of both, SBV and the related Akabane virus. All vaccinated cattle and mice were fully protected against SBV challenge infection. Furthermore, in the absence of antibodies against the viral N-protein, differentiation between vaccinated and field-infected animals allows an SBV marker vaccination concept. Moreover, the presented vaccine design also could be tested for other members of the Simbu serogroup and might allow the inclusion of additional immunogenic domains.

  14. The N-terminal domain of Schmallenberg virus envelope protein Gc is highly immunogenic and can provide protection from infection

    PubMed Central

    Wernike, Kerstin; Aebischer, Andrea; Roman-Sosa, Gleyder; Beer, Martin

    2017-01-01

    Schmallenberg virus (SBV) is transmitted by insect vectors, and therefore vaccination is one of the most important tools of disease control. In our study, novel subunit vaccines on the basis of an amino-terminal domain of SBV Gc of 234 amino acids (“Gc Amino”) first were tested and selected using a lethal small animal challenge model and then the best performing formulations also were tested in cattle. We could show that neither E. coli expressed nor the reduced form of “Gc Amino” protected from SBV infection. In contrast, both, immunization with “Gc Amino”-encoding DNA plasmids and “Gc-amino” expressed in a mammalian system, conferred protection in up to 66% of the animals. Interestingly, the best performance was achieved with a multivalent antigen containing the covalently linked Gc domains of both, SBV and the related Akabane virus. All vaccinated cattle and mice were fully protected against SBV challenge infection. Furthermore, in the absence of antibodies against the viral N-protein, differentiation between vaccinated and field-infected animals allows an SBV marker vaccination concept. Moreover, the presented vaccine design also could be tested for other members of the Simbu serogroup and might allow the inclusion of additional immunogenic domains. PMID:28211908

  15. SAFEGUARDS ENVELOPE

    SciTech Connect

    Duc Cao; Richard Metcalf

    2010-07-01

    The Safeguards Envelope is a strategy to determine a set of specific operating parameters within which nuclear facilities may operate to maximize safeguards effectiveness without sacrificing safety or plant efficiency. This paper details advanced statistical techniques that will be applied to real plant process monitoring (PM) data from the Idaho Chemical Processing Plant (ICPP). In a simulation based on this data, multi-tank and multi-attribute correlations were tested against synthetic diversion scenarios. Kernel regression smoothing was used to fit a curve to the historical data, and multivariable, residual analysis and cumulative sum techniques set parameters for operating conditions. Diversion scenarios were created and tested, showing improved results when compared with a previous study utilizing only one-variable Z-testing. A brief analysis of the impact of the safeguards optimization on the rest of plant efficiency, criticality concerns, and overall requirements is presented.

  16. Nonstructural protein 2 (nsP2) of Chikungunya virus (CHIKV) enhances protective immunity mediated by a CHIKV envelope protein expressing DNA Vaccine.

    PubMed

    Bao, Huihui; Ramanathan, Aarti A; Kawalakar, Omkar; Sundaram, Senthil G; Tingey, Colleen; Bian, Charoran B; Muruganandam, Nagarajan; Vijayachari, Paluru; Sardesai, Niranjan Y; Weiner, David B; Ugen, Kenneth E; Muthumani, Karuppiah

    2013-02-01

    Chikungunya virus (CHIKV) is an important emerging mosquito-borne alphavirus, indigenous to tropical Africa and Asia. It can cause epidemic fever and acute illness characterized by fever and arthralgias. The epidemic cycle of this infection is similar to dengue and urban yellow fever viral infections. The generation of an efficient vaccine against CHIKV is necessary to prevent and/or control the disease manifestations of the infection. In this report, we studied immune response against a CHIKV-envelope DNA vaccine (pEnv) and the role of the CHIKV nonstructural gene 2 (nsP2) as an adjuvant for the induction of protective immune responses in a relevant mouse challenge model. When injected with the CHIKV pEnv alone, 70% of the immunized mice survived CHIKV challenge, whereas when co-injected with pEnv+pnsP2, 90% of the mice survived viral challenge. Mice also exhibited a delayed onset signs of illness, and a marked decrease in morbidity, suggesting a nsP2 mediated adjuvant effect. Co-injection of the pnsP2 adjuvant with pEnv also qualitatively and quantitatively increased antigen specific neutralizing antibody responses compared to vaccination with pEnv alone. In sum, these novel data imply that the addition of nsP2 to the pEnv vaccine enhances anti-CHIKV-Env immune responses and maybe useful to include in future CHIKV clinical vaccination strategies.

  17. Protection of red-legged partridges (Alectoris rufa) against West Nile virus (WNV) infection after immunization with WNV recombinant envelope protein E (rE).

    PubMed

    Escribano-Romero, E; Gamino, V; Merino-Ramos, T; Blázquez, A B; Martín-Acebes, M A; de Oya, N Jiménez; Gutiérrez-Guzmán, A V; Escribano, José M; Höfle, U; Saiz, J C

    2013-09-23

    West Nile virus (WNV) is maintained in nature in an enzootic transmission cycle between birds and mosquitoes, although it occasionally infects other vertebrates, including humans, in which it may result fatal. To date, no licensed vaccines against WNV infection are available for birds, but its availability would certainly benefit certain populations, as birds grown for restocking, hunting activities, or alimentary purposes, and those confined to wildlife reservations and recreation installations. We have tested the protective capability of WNV envelope recombinant (rE) protein in red-legged partridges (Alectoris rufa). Birds (n=28) were intramuscularly immunized three times at 2-weeks interval with rE and a control group (n=29) was sham-immunized. Except for 5 sham-immunized birds that were not infected and housed as contact controls, partridges were subcutaneously challenged with WNV. Oropharyngeal and cloacal swabs and feather pulps were collected at several days after infection and blood samples were taken during vaccination and after infection. All rE-vaccinated partridges elicited anti-WNV antibodies before challenge and survived to the infection, while 33.3% of the sham-immunized birds succumbed, as did 25% of the contact animals. Most (84%) unvaccinated birds showed viremia 3 d.p.i., but virus was only detected in 14% of the rE vaccinated birds. WNV-RNA was detected in feathers and swabs from sham-immunized partridges from 3 to 7 d.p.i., mainly in birds that succumbed to the infection, but not in rE vaccinated birds. Thus, rE vaccination fully protected partridges against WND and reduced the risk of virus spread.

  18. Development, Implementation, and Pilot Evaluation of a Model-Driven Envelope Protection System to Mitigate the Hazard of In-Flight Ice Contamination on a Twin-Engine Commuter Aircraft

    NASA Technical Reports Server (NTRS)

    Martos, Borja; Ranaudo, Richard; Norton, Billy; Gingras, David; Barnhart, Billy

    2014-01-01

    Fatal loss-of-control accidents have been directly related to in-flight airframe icing. The prototype system presented in this report directly addresses the need for real-time onboard envelope protection in icing conditions. The combination of prior information and real-time aerodynamic parameter estimations are shown to provide sufficient information for determining safe limits of the flight envelope during inflight icing encounters. The Icing Contamination Envelope Protection (ICEPro) system was designed and implemented to identify degradations in airplane performance and flying qualities resulting from ice contamination and provide safe flight-envelope cues to the pilot. The utility of the ICEPro system for mitigating a potentially hazardous icing condition was evaluated by 29 pilots using the NASA Ice Contamination Effects Flight Training Device. Results showed that real time assessment cues were effective in reducing the number of potentially hazardous upset events and in lessening exposure to loss of control following an incipient upset condition. Pilot workload with the added ICEPro displays was not measurably affected, but pilot opinion surveys showed that real time cueing greatly improved their awareness of a hazardous aircraft state. The performance of ICEPro system was further evaluated by various levels of sensor noise and atmospheric turbulence.

  19. Elevated temperature envelope forming

    NASA Technical Reports Server (NTRS)

    Burg, Bruce M. (Inventor); Gane, David H. (Inventor); Starowski, Robert M. (Inventor)

    1992-01-01

    Elevated temperature envelope forming includes enclosing a part blank and form tool within an envelope sealed against the atmosphere, heat treating the combination while forming pressure holds the envelope and part against the form tool, and allowing part cool down to occur in an inert atmosphere with forming pressure removed. The forming pressure is provided by evacuating the envelope and may be aided by differential force applied between the envelope and the form tool.

  20. 40 CFR 426.120 - Applicability; description of the incandescent lamp envelope manufacturing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... incandescent lamp envelope manufacturing subcategory. 426.120 Section 426.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Incandescent Lamp Envelope Manufacturing Subcategory § 426.120...

  1. 40 CFR 426.120 - Applicability; description of the incandescent lamp envelope manufacturing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... incandescent lamp envelope manufacturing subcategory. 426.120 Section 426.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Incandescent Lamp Envelope Manufacturing Subcategory § 426.120...

  2. 40 CFR 426.120 - Applicability; description of the incandescent lamp envelope manufacturing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... incandescent lamp envelope manufacturing subcategory. 426.120 Section 426.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Incandescent Lamp Envelope Manufacturing Subcategory § 426.120 Applicability; description of...

  3. 40 CFR 426.120 - Applicability; description of the incandescent lamp envelope manufacturing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... incandescent lamp envelope manufacturing subcategory. 426.120 Section 426.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) GLASS MANUFACTURING POINT SOURCE CATEGORY Incandescent Lamp Envelope Manufacturing Subcategory § 426.120...

  4. 40 CFR 426.120 - Applicability; description of the incandescent lamp envelope manufacturing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... incandescent lamp envelope manufacturing subcategory. 426.120 Section 426.120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Incandescent Lamp Envelope Manufacturing Subcategory § 426.120 Applicability; description of...

  5. Envelope-modified single-cycle simian immunodeficiency virus selectively enhances antibody responses and partially protects against repeated, low-dose vaginal challenge.

    PubMed

    Alpert, Michael D; Rahmberg, Andrew R; Neidermyer, William; Ng, Sharon K; Carville, Angela; Camp, Jeremy V; Wilson, Robert L; Piatak, Michael; Mansfield, Keith G; Li, Wenjun; Miller, Christopher J; Lifson, Jeffrey D; Kozlowski, Pamela A; Evans, David T

    2010-10-01

    Immunization of rhesus macaques with strains of simian immunodeficiency virus (SIV) that are limited to a single cycle of infection elicits T-cell responses to multiple viral gene products and antibodies capable of neutralizing lab-adapted SIV, but not neutralization-resistant primary isolates of SIV. In an effort to improve upon the antibody responses, we immunized rhesus macaques with three strains of single-cycle SIV (scSIV) that express envelope glycoproteins modified to lack structural features thought to interfere with the development of neutralizing antibodies. These envelope-modified strains of scSIV lacked either five potential N-linked glycosylation sites in gp120, three potential N-linked glycosylation sites in gp41, or 100 amino acids in the V1V2 region of gp120. Three doses consisting of a mixture of the three envelope-modified strains of scSIV were administered on weeks 0, 6, and 12, followed by two booster inoculations with vesicular stomatitis virus (VSV) G trans-complemented scSIV on weeks 18 and 24. Although this immunization regimen did not elicit antibodies capable of detectably neutralizing SIV(mac)239 or SIV(mac)251(UCD), neutralizing antibody titers to the envelope-modified strains were selectively enhanced. Virus-specific antibodies and T cells were observed in the vaginal mucosa. After 20 weeks of repeated, low-dose vaginal challenge with SIV(mac)251(UCD), six of eight immunized animals versus six of six naïve controls became infected. Although immunization did not significantly reduce the likelihood of acquiring immunodeficiency virus infection, statistically significant reductions in peak and set point viral loads were observed in the immunized animals relative to the naïve control animals.

  6. Protective role of the RpoE (σE) and Cpx envelope stress responses against gentamicin killing of nongrowing Escherichia coli incubated under aerobic, phosphate starvation conditions.

    PubMed

    Moreau, Patrice L

    2014-08-01

    The viability of Escherichia coli starved of nitrogen (N) or phosphorus (P) decreased by up to seven orders of magnitude during prolonged incubation under aerobic conditions when exposed to high levels of the antibiotic gentamicin, whereas viability of cells starved of carbon (C) was barely affected. However, the initial rate of killing was lower for P-starved cells than for N-starved cells. The transient resistance of P-starved cells was partially dependent upon the expression of the phosphate (Pho) and Cpx responses. Constitutive activity of the Cpx and RpoE (σ(E)) envelope stress regulons increased the resistance of P- and N-starved cells. The level of expression of the RpoE regulon was fourfold higher in P-starved cells than in N-starved cell at the time gentamicin was added. Gentamicin killing of nongrowing cells may thus require ongoing aerobic glucose metabolism and faulty synthesis of structural membrane proteins. However, membrane protein damage induced by gentamicin can be eliminated or repaired by RpoE- and Cpx-dependent mechanisms pre-emptively induced in P-starved cells, which reveals a novel mechanism of resistance to gentamicin that is active in certain circumstances.

  7. FRACTIONAL CRYSTALLIZATION FEED ENVELOPE

    SciTech Connect

    HERTING DL

    2008-03-19

    Laboratory work was completed on a set of evaporation tests designed to establish a feed envelope for the fractional crystallization process. The feed envelope defines chemical concentration limits within which the process can be operated successfully. All 38 runs in the half-factorial design matrix were completed successfully, based on the qualitative definition of success. There is no feed composition likely to be derived from saltcake dissolution that would cause the fractional crystallization process to not meet acceptable performance requirements. However, some compositions clearly would provide more successful operation than other compositions.

  8. 40 CFR 426.110 - Applicability; description of the television picture tube envelope manufacturing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... television picture tube envelope manufacturing subcategory. 426.110 Section 426.110 Protection of Environment... CATEGORY Television Picture Tube Envelope Manufacturing Subcategory § 426.110 Applicability; description of the television picture tube envelope manufacturing subcategory. The provisions of this subpart...

  9. 40 CFR 426.110 - Applicability; description of the television picture tube envelope manufacturing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... television picture tube envelope manufacturing subcategory. 426.110 Section 426.110 Protection of Environment... POINT SOURCE CATEGORY Television Picture Tube Envelope Manufacturing Subcategory § 426.110 Applicability; description of the television picture tube envelope manufacturing subcategory. The provisions of this...

  10. 40 CFR 426.110 - Applicability; description of the television picture tube envelope manufacturing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... television picture tube envelope manufacturing subcategory. 426.110 Section 426.110 Protection of Environment... POINT SOURCE CATEGORY Television Picture Tube Envelope Manufacturing Subcategory § 426.110 Applicability; description of the television picture tube envelope manufacturing subcategory. The provisions of this...

  11. 40 CFR 426.110 - Applicability; description of the television picture tube envelope manufacturing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... television picture tube envelope manufacturing subcategory. 426.110 Section 426.110 Protection of Environment... CATEGORY Television Picture Tube Envelope Manufacturing Subcategory § 426.110 Applicability; description of the television picture tube envelope manufacturing subcategory. The provisions of this subpart...

  12. 40 CFR 426.110 - Applicability; description of the television picture tube envelope manufacturing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... television picture tube envelope manufacturing subcategory. 426.110 Section 426.110 Protection of Environment... POINT SOURCE CATEGORY Television Picture Tube Envelope Manufacturing Subcategory § 426.110 Applicability; description of the television picture tube envelope manufacturing subcategory. The provisions of this...

  13. Pushing the endogenous envelope

    PubMed Central

    Henzy, Jamie E.; Johnson, Welkin E.

    2013-01-01

    The majority of retroviral envelope glycoproteins characterized to date are typical of type I viral fusion proteins, having a receptor binding subunit associated with a fusion subunit. The fusion subunits of lentiviruses and alpha-, beta-, delta- and gammaretroviruses have a very conserved domain organization and conserved features of secondary structure, making them suitable for phylogenetic analyses. Such analyses, along with sequence comparisons, reveal evidence of numerous recombination events in which retroviruses have acquired envelope glycoproteins from heterologous sequences. Thus, the envelope gene (env) can have a history separate from that of the polymerase gene (pol), which is the most commonly used gene in phylogenetic analyses of retroviruses. Focusing on the fusion subunits of the genera listed above, we describe three distinct types of retroviral envelope glycoproteins, which we refer to as gamma-type, avian gamma-type and beta-type. By tracing these types within the ‘fossil record’ provided by endogenous retroviruses, we show that they have surprisingly distinct evolutionary histories and dynamics, with important implications for cross-species transmissions and the generation of novel lineages. These findings validate the utility of env sequences in contributing phylogenetic signal that enlarges our understanding of retrovirus evolution. PMID:23938755

  14. Jacketed lamp bulb envelope

    DOEpatents

    MacLennan, Donald A.; Turner, Brian P.; Gitsevich, Aleksandr; Bass, Gary K.; Dolan, James T.; Kipling, Kent; Kirkpatrick, Douglas A.; Leng, Yongzhang; Levin, Izrail; Roy, Robert J.; Shanks, Bruce; Smith, Malcolm; Trimble, William C.; Tsai, Peter

    2001-01-01

    A jacketed lamp bulb envelope includes a ceramic cup having an open end and a partially closed end, the partially closed end defining an aperture, a lamp bulb positioned inside the ceramic cup abutting the aperture, and a reflective ceramic material at least partially covering a portion of the bulb not abutting the aperture. The reflective ceramic material may substantially fill an interior volume of the ceramic cup not occupied by the bulb. The ceramic cup may include a structural feature for aiding in alignment of the jacketed lamp bulb envelope in a lamp. The ceramic cup may include an external flange about a periphery thereof. One example of a jacketed lamp bulb envelope includes a ceramic cup having an open end and a closed end, a ceramic washer covering the open end of the ceramic cup, the washer defining an aperture therethrough, a lamp bulb positioned inside the ceramic cup abutting the aperture, and a reflective ceramic material filling an interior volume of the ceramic cup not occupied by the bulb. A method of packing a jacketed lamp bulb envelope of the type comprising a ceramic cup with a lamp bulb disposed therein includes the steps of filling the ceramic cup with a flowable slurry of reflective material, and applying centrifugal force to the cup to pack the reflective material therein.

  15. DNA vaccines encoding the envelope protein of West Nile virus lineages 1 or 2 administered intramuscularly, via electroporation and with recombinant virus protein induce partial protection in large falcons (Falco spp.).

    PubMed

    Fischer, Dominik; Angenvoort, Joke; Ziegler, Ute; Fast, Christine; Maier, Kristina; Chabierski, Stefan; Eiden, Martin; Ulbert, Sebastian; Groschup, Martin H; Lierz, Michael

    2015-08-17

    As West Nile virus (WNV) can cause lethal diseases in raptors, a vaccination prophylaxis of free-living and captive populations is desirable. In the absence of vaccines approved for birds, equine vaccines have been used in falcons, but full protection against WNV infection was not achieved. Therefore, two DNA vaccines encoding the ectodomain of the envelope protein of WNV lineages 1 and 2, respectively, were evaluated in 28 large falcons. Four different vaccination protocols were used, including electroporation and booster-injections of recombinant WNV domain III protein, before challenge with the live WNV lineage 1 strain NY99. Drug safety, plasmid shedding and antibody production were monitored during the vaccination period. Serological, virological, histological, immunohistochemical and molecular biological investigations were performed during the challenge trials. Antibody response following vaccination was low overall and lasted for a maximum of three weeks. Plasmid shedding was not detected at any time. Viremia, mortality and levels, but not duration, of oral virus shedding were reduced in all of the groups during the challenge trial compared to the non-vaccinated control group. Likewise, clinical scoring, levels of cloacal virus shedding and viral load in organs were significantly reduced in three vaccination groups. Histopathological findings associated with WNV infections (meningo-encephalitis, myocarditis, and arteritis) were present in all groups, but immunohistochemical detection of the viral antigen was reduced. In conclusion, the vaccines can be used safely in falcons to reduce mortality and clinical signs and to lower the risk of virus transmission due to decreased levels of virus shedding and viremia, but full protection was not achieved in all groups.

  16. Model scattering envelopes of young stellar objects. II - Infalling envelopes

    NASA Technical Reports Server (NTRS)

    Whitney, Barbara A.; Hartmann, Lee

    1993-01-01

    We present scattered light images for models of young stellar objects surrounded by dusty envelopes. The envelopes are assumed to have finite angular momentum and are falling in steady flow onto a disk. The model envelopes include holes, such as might be created by energetic bipolar flows. We calculate images using the Monte Carlo method to follow the light scattered in the dusty envelope and circumstellar disk, assuming that the photons originate from the central source. Adopting typical interstellar medium dust opacities and expected mass infall rates for protostars of about 10 exp -6 solar mass/yr, we find that detectable amounts of optical radiation can escape from envelopes falling into a disk as small as about 10-100 AU, depending upon the viewing angle and the size of the bipolar flow cavity. We suggest that the extended optical and near-IR light observed around several young stars is scattered by dusty infalling envelopes rather than disks.

  17. Refrigerated cryogenic envelope

    DOEpatents

    Loudon, John D.

    1976-11-16

    An elongated cryogenic envelope including an outer tube and an inner tube coaxially spaced within said inner tube so that the space therebetween forms a vacuum chamber for holding a vacuum. The inner and outer tubes are provided with means for expanding or contracting during thermal changes. A shield is located in the vacuum chamber intermediate the inner and outer tubes; and, a refrigeration tube for directing refrigeration to the shield is coiled about at least a portion of the inner tube within the vacuum chamber to permit the refrigeration tube to expand or contract along its length during thermal changes within said vacuum chamber.

  18. Antiviral Activity of Graphene–Silver Nanocomposites against Non-Enveloped and Enveloped Viruses

    PubMed Central

    Chen, Yi-Ning; Hsueh, Yi-Huang; Hsieh, Chien-Te; Tzou, Dong-Ying; Chang, Pai-Ling

    2016-01-01

    The discovery of novel antiviral materials is important because many infectious diseases are caused by viruses. Silver nanoparticles have demonstrated strong antiviral activity, and graphene is a potential antimicrobial material due to its large surface area, high carrier mobility, and biocompatibility. No studies on the antiviral activity of nanomaterials on non-enveloped viruses have been reported. To investigate the antiviral activity of graphene oxide (GO) sheets and GO sheets with silver particles (GO-Ag) against enveloped and non-enveloped viruses, feline coronavirus (FCoV) with an envelope and infectious bursal disease virus (IBDV) without an envelope were chosen. The morphology and sizes of GO and GO-Ag were characterized by transmission, scanning electron microscopy, and X-ray diffraction. A virus inhibition assay was used to identify the antiviral activity of GO and GO-Ag. Go-Ag inhibited 25% of infection by FCoV and 23% by IBDV, whereas GO only inhibited 16% of infection by FCoV but showed no antiviral activity against the infection by IBDV. Further application of GO and GO-Ag can be considered for personal protection equipment to decrease the transmission of viruses. PMID:27104546

  19. Development of High Specific Strength Envelope Materials

    NASA Astrophysics Data System (ADS)

    Komatsu, Keiji; Sano, Masa-Aki; Kakuta, Yoshiaki

    Progress in materials technology has produced a much more durable synthetic fabric envelope for the non-rigid airship. Flexible materials are required to form airship envelopes, ballonets, load curtains, gas bags and covering rigid structures. Polybenzoxazole fiber (Zylon) and polyalirate fiber (Vectran) show high specific tensile strength, so that we developed membrane using these high specific tensile strength fibers as a load carrier. The main material developed is a Zylon or Vectran load carrier sealed internally with a polyurethane bonded inner gas retention film (EVOH). The external surface provides weather protecting with, for instance, a titanium oxide integrated polyurethane or Tedlar film. The mechanical test results show that tensile strength 1,000 N/cm is attained with weight less than 230g/m2. In addition to the mechanical properties, temperature dependence of the joint strength and solar absorptivity and emissivity of the surface are measured. 

  20. Cell Walls and the Convergent Evolution of the Viral Envelope

    PubMed Central

    Buchmann, Jan P.

    2015-01-01

    SUMMARY Why some viruses are enveloped while others lack an outer lipid bilayer is a major question in viral evolution but one that has received relatively little attention. The viral envelope serves several functions, including protecting the RNA or DNA molecule(s), evading recognition by the immune system, and facilitating virus entry. Despite these commonalities, viral envelopes come in a wide variety of shapes and configurations. The evolution of the viral envelope is made more puzzling by the fact that nonenveloped viruses are able to infect a diverse range of hosts across the tree of life. We reviewed the entry, transmission, and exit pathways of all (101) viral families on the 2013 International Committee on Taxonomy of Viruses (ICTV) list. By doing this, we revealed a strong association between the lack of a viral envelope and the presence of a cell wall in the hosts these viruses infect. We were able to propose a new hypothesis for the existence of enveloped and nonenveloped viruses, in which the latter represent an adaptation to cells surrounded by a cell wall, while the former are an adaptation to animal cells where cell walls are absent. In particular, cell walls inhibit viral entry and exit, as well as viral transport within an organism, all of which are critical waypoints for successful infection and spread. Finally, we discuss how this new model for the origin of the viral envelope impacts our overall understanding of virus evolution. PMID:26378223

  1. Fast Moreau envelope computation I

    NASA Astrophysics Data System (ADS)

    Lucet, Yves

    2006-11-01

    The present article summarizes the state of the art algorithms to compute the discrete Moreau envelope, and presents a new linear-time algorithm, named NEP for NonExpansive Proximal mapping. Numerical comparisons between the NEP and two existing algorithms: The Linear-time Legendre Transform (LLT) and the Parabolic Envelope (PE) algorithms are performed. Worst-case time complexity, convergence results, and examples are included. The fast Moreau envelope algorithms first factor the Moreau envelope as several one-dimensional transforms and then reduce the brute force quadratic worst-case time complexity to linear time by using either the equivalence with Fast Legendre Transform algorithms, the computation of a lower envelope of parabolas, or, in the convex case, the non expansiveness of the proximal mapping.

  2. Border safety: quality control at the nuclear envelope

    PubMed Central

    Webster, Brant M.; Lusk, C. Patrick

    2015-01-01

    The unique biochemical identity of the nuclear envelope confers its capacity to establish a barrier that protects the nuclear compartment and directly contributes to nuclear function. Recent work uncovered quality control mechanisms employing the ESCRT machinery and a new arm of ERAD to counteract the unfolding, damage or misassembly of nuclear envelope proteins and ensure the integrity of the nuclear envelope membranes. Moreover, cells have the capacity to recognize and triage defective nuclear pore complexes in order to prevent their inheritance and preserve the longevity of progeny. These mechanisms serve to highlight the diverse strategies used by cells to maintain nuclear compartmentalization; we suggest they mitigate the progression and severity of diseases associated with nuclear envelope malfunction like the laminopathies. PMID:26437591

  3. Envelope glycoprotein of arenaviruses.

    PubMed

    Burri, Dominique J; da Palma, Joel Ramos; Kunz, Stefan; Pasquato, Antonella

    2012-10-17

    Arenaviruses include lethal human pathogens which pose serious public health threats. So far, no FDA approved vaccines are available against arenavirus infections, and therapeutic options are limited, making the identification of novel drug targets for the development of efficacious therapeutics an urgent need. Arenaviruses are comprised of two RNA genome segments and four proteins, the polymerase L, the envelope glycoprotein GP, the matrix protein Z, and the nucleoprotein NP. A crucial step in the arenavirus life-cycle is the biosynthesis and maturation of the GP precursor (GPC) by cellular signal peptidases and the cellular enzyme Subtilisin Kexin Isozyme-1 (SKI-1)/Site-1 Protease (S1P) yielding a tripartite mature GP complex formed by GP1/GP2 and a stable signal peptide (SSP). GPC cleavage by SKI-1/S1P is crucial for fusion competence and incorporation of mature GP into nascent budding virion particles. In a first part of our review, we cover basic aspects and newer developments in the biosynthesis of arenavirus GP and its molecular interaction with SKI-1/S1P. A second part will then highlight the potential of SKI-1/S1P-mediated processing of arenavirus GPC as a novel target for therapeutic intervention to combat human pathogenic arenaviruses.

  4. Masonry building envelope analysis

    NASA Astrophysics Data System (ADS)

    McMullan, Phillip C.

    1993-04-01

    Over the past five years, infrared thermography has proven an effective tool to assist in required inspections on new masonry construction. However, with more thermographers providing this inspection service, establishing a standard for conducting these inspections is imperative. To attempt to standardize these inspections, it is important to understand the nature of the inspection as well as the context in which the inspection is typically conducted. The inspection focuses on evaluating masonry construction for compliance with the design specifications with regard to structural components and thermal performance of the building envelope. The thermal performance of the building includes both the thermal resistance of the material as well as infiltration/exfiltration characteristics. Given that the inspections occur in the 'field' rather than the controlled environment of a laboratory, there are numerous variables to be considered when undertaking this type of inspection. Both weather and site conditions at the time of the inspection can vary greatly. In this paper we will look at the variables encountered during recent inspections. Additionally, the author will present the standard which was employed in collecting this field data. This method is being incorporated into a new standard to be included in the revised version of 'Guidelines for Specifying and Performing Infrared Inspections' developed by the Infraspection Institute.

  5. Multifamily Envelope Leakage Model

    SciTech Connect

    Faakye, Omari; Griffiths, Dianne

    2015-05-08

    “The cost for blower testing is high, because it is labor intensive, and it may disrupt occupants in multiple units. This high cost and disruption deter program participants, and dissuade them from pursuing energy improvements that would trigger air leakage testing, such as improvements to the building envelope.” This statement found in a 2012 report by Heschong Mahone Group for several California interests emphasizes the importance of reducing the cost and complexity of blower testing in multifamily buildings. Energy efficiency opportunities are being bypassed. The cost of single blower testing is on the order of $300. The cost for guarded blower door testing—the more appropriate test for assessing energy savings opportunities—could easily be six times that, and that’s only if you have the equipment and simultaneous access to multiple apartments. Thus, the proper test is simply not performed. This research seeks to provide an algorithm for predicting the guarded blower door test result based upon a single, total blower door test.

  6. Selective induction of cell-mediated immunity and protection of rhesus macaques from chronic SHIV{sub KU2} infection by prophylactic vaccination with a conserved HIV-1 envelope peptide-cocktail

    SciTech Connect

    Nehete, Pramod N.; Nehete, Bharti P.; Hill, Lori; Manuri, Pallavi R.; Baladandayuthapani, Veerabhadran; Feng Lei; Simmons, Johnny; Sastry, K. Jagannadha

    2008-01-05

    Infection of Indian-origin rhesus macaques by the simian human immunodeficiency virus (SHIV) is considered to be a suitable preclinical model for directly testing efficacy of vaccine candidates based on the HIV-1 envelope. We used this model for prophylactic vaccination with a peptide-cocktail comprised of highly conserved HIV-1 envelope sequences immunogenic/antigenic in macaques and humans. Separate groups of macaques were immunized with the peptide-cocktail by intravenous and subcutaneous routes using autologous dendritic cells (DC) and Freund's adjuvant, respectively. The vaccine elicited antigen specific IFN-{gamma}-producing cells and T-cell proliferation, but not HIV-neutralizing antibodies. The vaccinated animals also exhibited efficient cross-clade cytolytic activity against target cells expressing envelope proteins corresponding to HIV-1 strains representative of multiple clades that increased after intravenous challenge with pathogenic SHIV{sub KU2}. Virus-neutralizing antibodies were either undetectable or present only transiently at low levels in the control as well as vaccinated monkeys after infection. Significant control of plasma viremia leading to undetectable levels was achieved in majority of vaccinated monkeys compared to mock-vaccinated controls. Monkeys vaccinated with the peptide-cocktail using autologous DC, compared to Freund's adjuvant, and the mock-vaccinated animals, showed significantly higher IFN-{gamma} production, higher levels of vaccine-specific IFN-{gamma} producing CD4{sup +} cells and significant control of plasma viremia. These results support DC-based vaccine delivery and the utility of the conserved HIV-1 envelope peptide-cocktail, capable of priming strong cell-mediated immunity, for potential inclusion in HIV vaccination strategies.

  7. Regulation of bacterial virulence gene expression by cell envelope stress responses

    PubMed Central

    Flores-Kim, Josué; Darwin, Andrew J

    2014-01-01

    The bacterial cytoplasm lies within a multilayered envelope that must be protected from internal and external hazards. This protection is provided by cell envelope stress responses (ESRs), which detect threats and reprogram gene expression to ensure survival. Pathogens frequently need these ESRs to survive inside the host, where their envelopes face dangerous environmental changes and attack from antimicrobial molecules. In addition, some virulence genes have become integrated into ESR regulons. This might be because these genes can protect the cell envelope from damage by host molecules, or it might help ESRs to reduce stress by moderating the assembly of virulence factors within the envelope. Alternatively, it could simply be a mechanism to coordinate the induction of virulence gene expression with entry into the host. Here, we briefly describe some of the bacterial ESRs, followed by examples where they control virulence gene expression in both Gram-negative and Gram-positive pathogens. PMID:25603429

  8. Enhancing the Envelope

    ERIC Educational Resources Information Center

    Kennedy, Mike

    2005-01-01

    With energy prices escalating, schools and universities have enormous incentive to control heating and cooling costs. And, as concerns about campus security and student safety continue to be paramount, education administrators have a duty to make sure their facilities are protected from intruders, vandals or other criminals. At the same time,…

  9. Personnel occupied woven envelope robot

    NASA Technical Reports Server (NTRS)

    Wessling, F. C.

    1986-01-01

    The use of nonmetallic or fabric structures for space application is considered. The following structures are suggested: (1) unpressurized space hangars; (2) extendable tunnels for soft docking; and (3) manned habitat for space stations, storage facilities, and work structures. The uses of the tunnel as a passageway: for personnel and equipment, eliminating extravehicular activity, for access to a control cabin on a space crane and between free flyers and the space station are outlined. The personnal occupied woven envelope robot (POWER) device is shown. The woven envelope (tunnel) acts as part of the boom of a crane. Potential applications of POWER are outlined. Several possible deflection mechanisms and design criteria are determined.

  10. Carbon chemistry of circumstellar envelopes

    NASA Technical Reports Server (NTRS)

    Bieging, John H.

    1990-01-01

    The chemical composition of envelopes surrounding cool evolved stars, as determined from microwave spectroscopic observations, is reviewed. Emphasis is placed on recent observations with the new large mm-wavelength telescopes and interferometer arrays, and on new theoretical work, especially concerning ion-molecule chemistry of carbon-bearing in these envelopes. Thermal (as opposed to maser) emission lines are discussed. Much progress has been made in the past few years in the theoretical understanding of these objects. It is already clear, however, that observations with the new generation of mm-telescopes will require substantial improvements in the theoretical models to achieve a thorough understanding of the data now becoming available.

  11. Rotavirus protein rearrangements in purified membrane-enveloped intermediate particles.

    PubMed Central

    Poruchynsky, M S; Atkinson, P H

    1991-01-01

    Rotavirus, a double-shelled nonenveloped member of the REoviridae family, becomes transiently membrane enveloped during its maturation process, as single-shelled particles bud from cytoplasmic viroplasm structures into the adjacent endoplasmic reticulum. The present study describes the isolation of these membrane-enveloped viral intermediates from rotavirus SA11-infected Ma104 cells. The enveloped intermediates comprised the proteins VP1, VP2, VP4, VP6, VP7, and NS28 and small amounts of NS35 and NS34. VP7 in the intermediate particles was recognized by either a polyclonal antibody to VP7, which previous studies had shown recognizes the membrane-associated form of VP7, or a monoclonal antibody which recognizes VP7 on mature virus. NS28, VP7, and VP4 could be complexed to a higher-molecular-weight form when the membrane-permeable cross-linker dithiobis(succinimidylproprionate) was used. However, when an impermeable cross-linker was used, the structural proteins, including VP7, were not accessible to cross-linking. Velocity sedimentation of cross-linked immunoisolated enveloped virus particles showed that VP7 and VP4 were located in the same fractions only when the membrane-permeable cross-linker was used, implying their heterooligomeric association during outer capsid formation. When intermediate enveloped virus particles were treated with protease, VP6 and VP7 were protected, but not in the presence of detergent. Taken together, these results support the idea that in the membrane-enveloped intermediate, VP7 is repositioned from its location in the endoplasmic reticulum lumen back across the viral membrane envelope to the inferior of the virus particle during the maturation process. Images PMID:1651404

  12. Using a Down-Scaled Bioclimate Envelope Model to Determine Long-Term Temporal Connectivity of Garry oak ( Quercus garryana) Habitat in Western North America: Implications for Protected Area Planning

    NASA Astrophysics Data System (ADS)

    Pellatt, Marlow G.; Goring, Simon J.; Bodtker, Karin M.; Cannon, Alex J.

    2012-04-01

    Under the Canadian Species at Risk Act (SARA), Garry oak ( Quercus garryana) ecosystems are listed as "at-risk" and act as an umbrella for over one hundred species that are endangered to some degree. Understanding Garry oak responses to future climate scenarios at scales relevant to protected area managers is essential to effectively manage existing protected area networks and to guide the selection of temporally connected migration corridors, additional protected areas, and to maintain Garry oak populations over the next century. We present Garry oak distribution scenarios using two random forest models calibrated with down-scaled bioclimatic data for British Columbia, Washington, and Oregon based on 1961-1990 climate normals. The suitability models are calibrated using either both precipitation and temperature variables or using only temperature variables. We compare suitability predictions from four General Circulation Models (GCMs) and present CGCM2 model results under two emissions scenarios. For each GCM and emissions scenario we apply the two Garry oak suitability models and use the suitability models to determine the extent and temporal connectivity of climatically suitable Garry oak habitat within protected areas from 2010 to 2099. The suitability models indicate that while 164 km2 of the total protected area network in the region (47,990 km2) contains recorded Garry oak presence, 1635 and 1680 km2 of climatically suitable Garry oak habitat is currently under some form of protection. Of this suitable protected area, only between 6.6 and 7.3% will be "temporally connected" between 2010 and 2099 based on the CGCM2 model. These results highlight the need for public and private protected area organizations to work cooperatively in the development of corridors to maintain temporal connectivity in climatically suitable areas for the future of Garry oak ecosystems.

  13. Using a down-scaled bioclimate envelope model to determine long-term temporal connectivity of Garry oak (Quercus garryana) habitat in western North America: implications for protected area planning.

    PubMed

    Pellatt, Marlow G; Goring, Simon J; Bodtker, Karin M; Cannon, Alex J

    2012-04-01

    Under the Canadian Species at Risk Act (SARA), Garry oak (Quercus garryana) ecosystems are listed as "at-risk" and act as an umbrella for over one hundred species that are endangered to some degree. Understanding Garry oak responses to future climate scenarios at scales relevant to protected area managers is essential to effectively manage existing protected area networks and to guide the selection of temporally connected migration corridors, additional protected areas, and to maintain Garry oak populations over the next century. We present Garry oak distribution scenarios using two random forest models calibrated with down-scaled bioclimatic data for British Columbia, Washington, and Oregon based on 1961-1990 climate normals. The suitability models are calibrated using either both precipitation and temperature variables or using only temperature variables. We compare suitability predictions from four General Circulation Models (GCMs) and present CGCM2 model results under two emissions scenarios. For each GCM and emissions scenario we apply the two Garry oak suitability models and use the suitability models to determine the extent and temporal connectivity of climatically suitable Garry oak habitat within protected areas from 2010 to 2099. The suitability models indicate that while 164 km(2) of the total protected area network in the region (47,990 km(2)) contains recorded Garry oak presence, 1635 and 1680 km(2) of climatically suitable Garry oak habitat is currently under some form of protection. Of this suitable protected area, only between 6.6 and 7.3% will be "temporally connected" between 2010 and 2099 based on the CGCM2 model. These results highlight the need for public and private protected area organizations to work cooperatively in the development of corridors to maintain temporal connectivity in climatically suitable areas for the future of Garry oak ecosystems.

  14. Safeguards Envelope Progress FY08

    SciTech Connect

    Robert Bean; Richard Metcalf; Aaron Bevill

    2008-09-01

    The Safeguards Envelope Project met its milestones by creating a rudimentary safeguards envelope, proving the value of the approach on a small scale, and determining the most appropriate path forward. The Idaho Chemical Processing Plant’s large cache of reprocessing process monitoring data, dubbed UBER Data, was recovered and used in the analysis. A probabilistic Z test was used on a Markov Monte Carlo simulation of expected diversion data when compared with normal operating data. The data regarding a fully transient event in a tank was used to create a simple requirement, representative of a safeguards envelope, whose impact was a decrease in operating efficiency by 1.3% but an increase in material balance period of 26%. This approach is operator, state, and international safeguards friendly and should be applied to future reprocessing plants. Future requirements include tank-to-tank correlations in reprocessing facilities, detailed operations impact studies, simulation inclusion, automated optimization, advanced statistics analysis, and multi-attribute utility analysis.

  15. Heat recovery in building envelopes

    SciTech Connect

    Walker, Iain S.; Sherman, Max H.

    2003-08-01

    Infiltration has traditionally been assumed to contribute to the energy load of a building by an amount equal to the product of the infiltration flow rate and the enthalpy difference between inside and outside. Some studies have indicated that application of such a simple formula may produce an unreasonably high contribution because of heat recovery within the building envelope. The major objective of this study was to provide an improved prediction of the energy load due to infiltration by introducing a correction factor that multiplies the expression for the conventional load. This paper discusses simplified analytical modeling and CFD simulations that examine infiltration heat recovery (IHR) in an attempt to quantify the magnitude of this effect for typical building envelopes. For comparison, we will also briefly examine the results of some full-scale field measurements of IHR based on infiltration rates and energy use in real buildings. The results of this work showed that for houses with insulated walls the heat recovery is negligible due to the small fraction of the envelope that participates in heat exchange with the infiltrating air. However; there is the potential for IHR to have a significant effect for higher participation dynamic walls/ceilings or uninsulated walls. This result implies that the existing methods for evaluating infiltration related building loads provide adequate results for typical buildings.

  16. β-Casein hydrolysate generated by the cell envelope-associated proteinase of Lactobacillus delbrueckii ssp. lactis CRL 581 protects against trinitrobenzene sulfonic acid-induced colitis in mice.

    PubMed

    Espeche Turbay, M B; de Moreno de LeBlanc, A; Perdigón, G; Savoy de Giori, G; Hebert, E M

    2012-03-01

    Lactobacillus delbrueckii ssp. lactis CRL 581, a thermophilic lactic acid bacterium used as a starter culture for the manufacture of several fermented dairy products, possesses an efficient proteolytic system that is able to release a series of potentially bioactive peptides (i.e., antihypertensive and phosphopeptides) from α- and β-caseins. Considering the potential beneficial health effects of the peptides released by L. delbrueckii ssp. lactis CRL 581 from milk proteins, the aim of this work was to analyze the anti-mutagenic and anti-inflammatory properties of the casein hydrolysates generated by the cell envelope-associated proteinase of this bacterium. The ability of α- and β-casein hydrolysates to suppress the mutagenesis of a direct-acting mutagen 4-nitroquinoline-N-oxide on Salmonella typhimurium TA 98 and TA 100 increased concomitantly with the time of casein hydrolysis. The anti-inflammatory effect of the β-casein hydrolysate was evaluated using a trinitrobenzene sulfonic acid (TNBS)-induced Crohn's disease murine model. The hydrolysate was administered to mice 10 d before the intrarectal inoculation of TNBS. The mice that received β-casein hydrolysate previously to TNBS showed decreased mortality rates, faster recovery of initial body weight loss, less microbial translocation to the liver, decreased β-glucuronidase and myeloperoxidase activities in the gut, and decreased colonic macroscopic and microscopic damage compared with the animals that did not receive this hydrolysate. In addition, β-casein hydrolysate exerted a beneficial effect on acute intestinal inflammation by increased interleukin 10 and decreased IFN-γ production in the gut. Our findings are consistent with the health-promoting attributes of the milk products fermented by L. delbrueckii ssp. lactis CRL 581 and open up new opportunities for developing novel functional foods.

  17. The structure of common-envelope remnants

    NASA Astrophysics Data System (ADS)

    Hall, Philip D.

    2015-05-01

    We investigate the structure and evolution of the remnants of common-envelope evolution in binary star systems. In a common-envelope phase, two stars become engulfed in a gaseous envelope and, under the influence of drag forces, spiral to smaller separations. They may merge to form a single star or the envelope may be ejected to leave the stars in a shorter period orbit. This process explains the short orbital periods of many observed binary systems, such as cataclysmic variables and low-mass X-ray binary systems. Despite the importance of these systems, and of common-envelope evolution to their formation, it remains poorly understood. Specifically, we are unable to confidently predict the outcome of a common-envelope phase from the properties at its onset. After presenting a review of work on stellar evolution, binary systems, common-envelope evolution and the computer programs used, we describe the results of three computational projects on common-envelope evolution. Our work specifically relates to the methods and prescriptions which are used for predicting the outcome. We use the Cambridge stellar-evolution code STARS to produce detailed models of the structure and evolution of remnants of common-envelope evolution. We compare different assumptions about the uncertain end-of-common envelope structure and envelope mass of remnants which successfully eject their common envelopes. In the first project, we use detailed remnant models to investigate whether planetary nebulae are predicted after common-envelope phases initiated by low-mass red giants. We focus on the requirement that a remnant evolves rapidly enough to photoionize the nebula and compare the predictions for different ideas about the structure at the end of a common-envelope phase. We find that planetary nebulae are possible for some prescriptions for the end-of-common envelope structure. In our second contribution, we compute a large set of single-star models and fit new formulae to the core radii of

  18. Solar envelope zoning: application to the city planning process. Los Angeles case study

    SciTech Connect

    Not Available

    1980-06-01

    Solar envelope zoning represents a promising approach to solar access protection. A solar envelope defines the volume within which a building will not shade adjacent lots or buildings. Other solar access protection techniques, such as privately negotiated easements, continue to be tested and implemented but none offer the degree of comprehensiveness evident in this approach. Here, the City of Los Angeles, through the Mayor's Energy Office, the City Planning Department, and the City Attorney's Office, examine the feasibility of translating the concept of solar envelopes into zoning techniques. They concluded that envelope zoning is a fair and consistent method of guaranteeing solar access, but problems of complexity and uncertainty may limit its usefulness. Envelope zoning may be inappropriate for the development of high density centers and for more restrictive community plans. Aids or tools to administer envelope zoning need to be developed. Finally, some combination of approaches, including publicly recorded easements, subdivision approval and envelope zoning, need to be adopted to encourage solar use in cities. (MHR)

  19. Diversity in the fertilization envelopes of echinoderms.

    PubMed

    Oulhen, Nathalie; Reich, Adrian; Wong, Julian L; Ramos, Isabela; Wessel, Gary M

    2013-01-01

    Cell surface changes in an egg at fertilization are essential to begin development and for protecting the zygote. Most fertilized eggs construct a barrier around themselves by modifying their original extracellular matrix. This construction usually results from calcium-induced exocytosis of cortical granules, the contents of which in sea urchins function to form the fertilization envelope (FE), an extracellular matrix of cortical granule contents built upon a vitelline layer scaffold. Here, we examined the molecular mechanism of this process in sea stars, a close relative of the sea urchins, and analyze the evolutionary changes that likely occurred in the functionality of this structure between these two organisms. We find that the FE of sea stars is more permeable than in sea urchins, allowing diffusion of molecules in excess of 2 megadaltons. Through a proteomic and transcriptomic approach, we find that most, but not all, of the proteins present in the sea urchin envelope are present in sea stars, including SFE9, proteoliaisin, and rendezvin. The mRNAs encoding these FE proteins accumulated most densely in early oocytes, and then beginning with vitellogenesis, these mRNAs decreased in abundance to levels nearly undetectable in eggs. Antibodies to the SFE9 protein of sea stars showed that the cortical granules in sea star also accumulated most significantly in early oocytes, but different from sea urchins, they translocated to the cortex of the oocytes well before meiotic initiation. These results suggest that the preparation for cell surface changes in sea urchins has been shifted to later in oogenesis, and perhaps reflects the meiotic differences among the species-sea star oocytes are stored in prophase of meiosis and fertilized during the meiotic divisions, as in most animals, whereas sea urchins are one of the few taxons in which eggs have completed meiosis prior to fertilization.

  20. Isolating The Building Thermal Envelope

    NASA Astrophysics Data System (ADS)

    Harrje, D. T.; Dutt, G. S.; Gadsby, K. J.

    1981-01-01

    The evaluation of the thermal integrity of building envelopes by infrared scanning tech-niques is often hampered in mild weather because temperature differentials across the envelope are small. Combining the infrared scanning with positive or negative building pressures, induced by a "blower door" or the building ventilation system, considerably extends the periods during which meaningful diagnostics can be conducted. Although missing or poorly installed insulation may lead to a substantial energy penalty, it is the search for air leakage sites that often has the largest potential for energy savings. Infrared inspection of the attic floor with air forced from the occupied space through ceiling by-passes, and inspecting the interior of the building when outside air is being sucked through the envelope reveals unexpected leakage sites. Portability of the diagnostic equipment is essential in these surveys which may include access into some tight spaces. A catalog of bypass heat losses that have been detected in residential housing using the combined infrared pressure differential technique is included to point out the wide variety of leakage sites which may compromise the benefits of thermal insulation and allow excessive air infiltration. Detection and suppression of such leaks should be key items in any building energy audit program. Where a calibrated blower door is used to pressurize or evacuate the house, the leakage rate can be quantified and an excessively tight house recognized. Houses that are too tight may be improved with a minimal energy penalty by forced ventilation,preferably with a heat recuperator and/or by providing combustion air directly to the furnace.

  1. Aircraft maneuver envelope warning system

    NASA Technical Reports Server (NTRS)

    Bivens, Courtland C. (Inventor); Rosado, Joel M. (Inventor); Lee, Burnett (Inventor)

    1994-01-01

    A maneuver envelope warning system for an aircraft having operating limits, operating condition sensors and an indicator driver. The indicator driver has a plurality of visual indicators. The indicator driver determines a relationship between sensed operating conditions and the operating limits; such as, a ratio therebetween. The indicator driver illuminates a number of the indicators in proportion to the determined relationship. The position of the indicators illuminated represents to a pilot in an easily ascertainable manner whether the operational conditions are approaching operational limits of the aircraft, and the degree to which operational conditions lie within or exceed operational limits.

  2. Flexible Envelope Request Notation (FERN)

    NASA Technical Reports Server (NTRS)

    Zoch, David R.; Lavallee, David; Weinstein, Stuart

    1991-01-01

    The following topics are presented in view graph form and include the following: scheduling application; the motivation for the Flexible Envelope Request Notation (FERN); characteristics of FERN; types of information needed in requests; where information is stored in requests; FERN structures; generic requests; resource availability for pooled resources; expressive notation; temporal constraints; time formats; changes to FERN; sample FERN requests; the temporal relationship between two steps; maximum activity length to limit step delays; alternative requests; the temporal relationship between two activities; and idle resource usage between steps.

  3. The psychic envelopes in psychoanalytic theories of infancy

    PubMed Central

    Mellier, Denis

    2014-01-01

    This paper aims to review the topic of psychic envelopes and to sketch the main outlines of this concept in infancy. We first explore the origins of the concept in Freud's “protective shield” and then its development in adult psychoanalysis before going on to see how this fits in infancy with post-Bionian psychoanalysis and development. Four central notions guide this review: (1) Freud's “protective shield” describes a barrier to protect the psychic apparatus against potentially overflowing trauma. It is a core notion which highlights a serious clinical challenge for patients for whom the shield is damaged or faulty: the risk of confusion of borders between the internal/external world, conscious/unconscious, mind/body, or self-conservation/sexuality. (2) Anzieu's “Skin-Ego” is defined by the different senses of the body. The different layers of experienced sensation, of this body-ego, go on to form the psychic envelope. This theory contributes to our understanding of how early trauma, due to the failures of maternal care, can continue to have an impact in adult life. (3) Bick's “psychic skin” establishes the concept in relation to infancy. The mother's containing functions allow a first psychic skin to develop, which then defines an infant's psychic space and affords the infant a degree of self-containment. Houzel then conceptualized this process as a stabilization of drive forces. (4) Stern's “narrative envelope” derives from the intersection between psychoanalysis and neuroscience. It gives us another way to conceptualize the development of pre-verbal communication. It may also pave the way for a finer distinction of different types of envelopes. Ultimately, in this review we find that psychic envelopes in infancy can be viewed from four different perspectives (economic, topographical, dynamic, and genetic) and recommend further investigation. PMID:25076924

  4. Safeguards Envelope Progress FY10

    SciTech Connect

    Richard Metcalf

    2010-10-01

    The Safeguards Envelope is a strategy to determine a set of specific operating parameters within which nuclear facilities may operate to maximize safeguards effectiveness without sacrificing safety or plant efficiency. This paper details the additions to the advanced operating techniques that will be applied to real plant process monitoring (PM) data from the Idaho Chemical Processing Plant (ICPP). Research this year focused on combining disparate pieces of data together to maximize operating time with minimal downtime due to safeguards. A Chi-Square and Croiser's cumulative sum were both included as part of the new analysis. Because of a major issue with the original data, the implementation of the two new tests did not add to the existing set of tests, though limited one-variable optimization made a small increase in detection probability. Additional analysis was performed to determine if prior analysis would have caused a major security or safety operating envelope issue. It was determined that a safety issue would have resulted from the prior research, but that the security may have been increased under certain conditions.

  5. Circumplanetary disc or circumplanetary envelope?

    NASA Astrophysics Data System (ADS)

    Szulágyi, J.; Masset, F.; Lega, E.; Crida, A.; Morbidelli, A.; Guillot, T.

    2016-08-01

    We present three-dimensional simulations with nested meshes of the dynamics of the gas around a Jupiter mass planet with the JUPITER and FARGOCA codes. We implemented a radiative transfer module into the JUPITER code to account for realistic heating and cooling of the gas. We focus on the circumplanetary gas flow, determining its characteristics at very high resolution (80 per cent of Jupiter's diameter). In our nominal simulation where the temperature evolves freely by the radiative module and reaches 13000 K at the planet, a circumplanetary envelope was formed filling the entire Roche lobe. Because of our equation of state is simplified and probably overestimates the temperature, we also performed simulations with limited maximal temperatures in the planet region (1000, 1500, and 2000 K). In these fixed temperature cases circumplanetary discs (CPDs) were formed. This suggests that the capability to form a CPD is not simply linked to the mass of the planet and its ability to open a gap. Instead, the gas temperature at the planet's location, which depends on its accretion history, plays also fundamental role. The CPDs in the simulations are hot and cooling very slowly, they have very steep temperature and density profiles, and are strongly sub-Keplerian. Moreover, the CPDs are fed by a strong vertical influx, which shocks on the CPD surfaces creating a hot and luminous shock-front. In contrast, the pressure supported circumplanetary envelope is characterized by internal convection and almost stalled rotation.

  6. Structural Basis for Membrane Anchoring of HIV-1 Envelope Spike

    PubMed Central

    Fu, Qingshan; Chen, Jia; Ha, Heather Jiwon; Ghantous, Fadi; Herrmann, Tobias; Chang, Weiting; Liu, Zhijun; Frey, Gary; Seaman, Michael S.; Chen, Bing; Chou, James J.

    2016-01-01

    HIV-1 envelope spike (Env) is a type I membrane protein that mediates viral entry. We use NMR to determine an atomic structure of the transmembrane (TM) domain of HIV-1 Env reconstituted in bicelles that mimic a lipid bilayer. The TM forms a well-ordered trimer that protects a conserved membrane-embedded arginine. An N-terminal coiled-coil and a C-terminal hydrophilic core stabilize the trimer. Individual mutations of conserved residues did not disrupt the TM trimer and minimally affected membrane fusion and infectivity. Major changes in the hydrophilic core, however, altered the antibody sensitivity of Env. These results show how a TM domain anchors, stabilizes and modulates a viral envelope spike and suggest that its influence on Env conformation is an important consideration for HIV-1 immunogen design. PMID:27338706

  7. Envelope glycoproteins of human immunodeficiency virus type 1: profound influences on immune functions.

    PubMed Central

    Chirmule, N; Pahwa, S

    1996-01-01

    Infection by human immunodeficiency virus type 1 (HIV-1) leads to progressive destruction of the CD4+ T-cell subset, resulting in immune deficiency and AIDS. The specific binding of the viral external envelope glycoprotein of HIV-1, gp120, to the CD4 molecules initiates viral entry. In the past few years, several studies have indicated that the interaction of HIV-1 envelope glycoprotein with cells and molecules of the immune system leads to pleiotropic biological effects on immune functions, which include effects on differentiation of CD34+ lymphoid progenitor cells and thymocytes, aberrant activation and cytokine secretion patterns of mature T cells, induction of apoptosis, B-cell hyperactivity, inhibition of T-cell dependent B-cell differentiation, modulation of macrophage functions, interactions with components of complement, and effects on neuronal cells. The amino acid sequence homologies of the envelope glycoproteins with several cellular proteins have suggested that molecular mimicry may play a role in the pathogenesis of the disease. This review summarizes work done by several investigators demonstrating the profound biological effects of envelope glycoproteins of HIV-1 on immune system cells. Extensive studies have also been done on interactions of the viral envelope proteins with components of the immune system which may be important for eliciting a "protective immune response." Understanding the influences of HIV-1 envelope glycoproteins on the immune system may provide valuable insights into HIV-1 disease pathogenesis and carries implications for the trials of HIV-1 envelope protein vaccines and immunotherapeutics. PMID:8801439

  8. Naked Viruses That Aren't Always Naked: Quasi-Enveloped Agents of Acute Hepatitis.

    PubMed

    Feng, Zongdi; Hirai-Yuki, Asuka; McKnight, Kevin L; Lemon, Stanley M

    2014-11-01

    Historically, viruses were considered to be either enveloped or nonenveloped. However, recent work on hepatitis A virus and hepatitis E virus challenges this long-held tenet. Whereas these human pathogens are shed in feces as naked nonenveloped virions, recent studies indicate that both circulate in the blood completely masked in membranes during acute infection. These membrane-wrapped virions are as infectious as their naked counterparts, although they do not express a virally encoded protein on their surface, thus distinguishing them from conventional enveloped viruses. The absence of a viral fusion protein implies that these quasi-enveloped virions have unique mechanisms for entry into cells. Like true enveloped viruses, however, these phylogenetically distinct viruses usurp components of the host ESCRT system to hijack host cell membranes and noncytolytically exit infected cells. The membrane protects these viruses from neutralizing antibodies, facilitating dissemination within the host, whereas nonenveloped virions shed in feces are stable in the environment, allowing for epidemic transmission.

  9. Evolution of Space Shuttle Range Safety (RS) Ascent Flight Envelope Design

    NASA Technical Reports Server (NTRS)

    Brewer, Joan D.

    2011-01-01

    Ascent flight envelopes are trajectories that define the normal operating region of a space vehicle s position from liftoff until the end of powered flight. They fulfill part of the RS data requirements imposed by the Air Force s 45th Space Wing (45SW) on space vehicles launching from the Eastern Range (ER) in Florida. The 45SW is chartered to protect the public by minimizing risks associated with the inherent hazards of launching a vehicle into space. NASA s Space Shuttle program has launched 130+ manned missions over a 30 year period from the ER. Ascent envelopes were delivered for each of those missions. The 45SW envelope requirements have remained largely unchanged during this time. However, the methodology and design processes used to generate the envelopes have evolved over the years to support mission changes, maintain high data quality, and reduce costs. The evolution of the Shuttle envelope design has yielded lessons learned that can be applied to future endevours. There have been numerous Shuttle ascent design enhancements over the years that have caused the envelope methodology to evolve. One of these Shuttle improvements was the introduction of onboard flight software changes implemented to improve launch probability. This change impacted the preflight nominal ascent trajectory, which is a key element in the RS envelope design. While the early Shuttle nominal trajectories were designed preflight using a representative monthly mean wind, the new software changes involved designing a nominal ascent trajectory on launch day using real-time winds. Because the actual nominal trajectory position was not known until launch day, the envelope analysis had to be customized to account for this nominal trajectory variation in addition to the other envelope components.

  10. A stamp on the envelope

    PubMed Central

    SANDERS, ROGIER W.; MOORE, JOHN P.

    2015-01-01

    A high-resolution crystal structure of the HIV-1 Env trimer proteins, in their form before they fuse with target cells, will aid the design of vaccines that elicit protective immune responses to this protein complex. PMID:25296251

  11. The theoretical polarization of pure scattering axisymmetric circumstellar envelopes

    NASA Technical Reports Server (NTRS)

    Fox, G. K.

    1994-01-01

    The Sobolev approach to the scattering of starlight through a pure scattering circumstellar envelope is developed. The theoretical polarization due to electron scattering in Be star envelopes is calculated for two geometries (an equatorially enhanced envelope and a spheroidal envelope). Only the disk-type envelope is found to yield a maximum polarization consistent with the observed range for Be stars. A lower limit, analytical approximation to the theoretical polarization from a pure scattering envelope is obtained.

  12. Safeguards Envelope Progress FY09

    SciTech Connect

    Richard Metcalf; Robert Bean

    2009-09-01

    The Safeguards Envelope is a strategy to determine a set of specific operating parameters which nuclear facilities may operate within to maximize safeguards effectiveness without sacrificing safety or plant efficiency. This paper details advanced statistical techniques will be applied to real plant process monitoring (PM) data from the Idaho Chemical Processing Plant (ICPP). As a result of the U.S. having no operating nuclear chemical reprocessing plants, there has been a strong interest in obtaining process monitoring data from the ICPP. The ICPP was shut down in 1996 and a recent effort has been made to retrieve the PM data from storage in a data mining effort. In a simulation based on this data, multi-tank and multi-attribute correlations were tested against synthetic diversion scenarios. Kernel regression smoothing was used to fit a curve to the historical data, and multivariable, residual analysis and cumulative sum techniques set parameters for operating conditions. Diversion scenarios were created and tested, showing improved results when compared with a previous study utilizing only one-variable Z- testing7.

  13. Personnel occupied woven envelope robot

    NASA Technical Reports Server (NTRS)

    Wessling, Francis; Teoh, William; Ziemke, M. Carl

    1988-01-01

    The Personnel Occupied Woven Envelope Robot (POWER) provides an alternative to extravehicular activity (EVA) of space suited astronauts and/or use of long slender manipulator arms such as are used in the Shuttle Remote Manipulator System. POWER provides the capability for a shirt sleeved astronaut to perform such work by entering a control pod through air locks at both ends of an inflated flexible bellows (access tunnel). The exoskeleton of the tunnel is a series of six degrees of freedom (Six-DOF) articulated links compressible to 1/6 of their fully extended length. The operator can maneuver the control pod to almost any location within about 50 m of the base attachment to the space station. POWER can be envisioned as a series of hollow Six-DOF manipulator segments or arms wherein each arm grasps the shoulder of the next arm. Inside the hollow arms ia a bellow-type access tunnel. The control pod is the fist of the series of linked hollow arms. The fingers of the fist are conventional manipulator arms under direct visual control of the nearby operator in the pod. The applications and progress to date of the POWER system is given.

  14. Resource envelope concepts for mission planning

    NASA Technical Reports Server (NTRS)

    Ibrahim, K. Y.; Weiler, J. D.; Tokaz, J. C.

    1991-01-01

    Seven proposed methods for creating resource envelopes for Space Station Freedom mission planning are detailed. Four reference science activity models are used to illustrate the effect of adding operational flexibility to mission timelines. For each method, a brief explanation is given along with graphs to illustrate the application of the envelopes to the power and crew resources. The benefits and costs of each method are analyzed in terms of resource utilization. In addition to the effect on individual activities, resource envelopes are analyzed at the experiment level.

  15. Radiative accelerations in stellar envelopes

    NASA Astrophysics Data System (ADS)

    Seaton, M. J.

    1997-08-01

    In stars which are sufficiently quiescent, changes in the relative abundances of the chemical elements can result from gravitational settling and from levitation produced by radiation pressure forces, usually expressed as radiative accelerations g_rad. Those changes can affect the structure of such stars, due to modifications in opacities, and can lead to marked peculiarities in observed atmospheric abundances. It is necessary to consider diffusive movements both in the atmospheres and in much deeper layers of the stellar envelopes. For the envelopes the equation of radiative transfer can be solved in a diffusion approximation and, for an element k in ionization stage j, one obtains expressions for g_rad(j, k) proportional to the total radiative flux, to the Rosseland-mean opacity kappa_R (which may depend on the abundance of k), and to a dimensionless quantity gamma(j, k) which, due to saturation effects, can be sensitive to the abundance of k. The radiative accelerations are required for each ionization stage, because the diffusion coefficients depend on j. Using atomic data obtained in the course of the work of the Opacity Project (OP), we calculate kappa_R and gamma(j, k) for the chemical elements C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Cr, Mn, Fe and Ni. We start from standard Solar system abundances, and then vary the abundance of one element at a time (element k) by a factor chi. The following results are obtained and are available at the Centre de Donnees astronomiques de Strasbourg (CDS). (1) Files stages.zz (where zz specifies the nuclear charge of the selected element k) containing values of kappa_R and gamma(j, k) on a mesh of values of (T, N_e, chi), where T is temperature, and N_e is electron density. We include derivatives of kappa_R and gamma(j, k) with respect to chi, which are used for making interpolations. (2) A code add.f which reads a file stages.zz and writes a file acc.zz containing values of gamma(k) obtained on summing the gamma(j, k

  16. Personnel occupied woven envelope robot power

    NASA Technical Reports Server (NTRS)

    Wessling, F. C.

    1988-01-01

    The Personnel Occupied Woven Envelope Robot (POWER) concept has evolved over the course of the study. The goal of the project was the development of methods and algorithms for solid modeling for the flexible robot arm.

  17. Transcriptional regulation at the yeast nuclear envelope

    PubMed Central

    Steglich, Babett; Sazer, Shelley; Ekwall, Karl

    2013-01-01

    The spatial organization of the genome inside the nucleus affects many nuclear processes, such as DNA replication, DNA repair, and gene transcription. In metazoans, the nuclear periphery harbors mainly repressed genes that associate with the nuclear lamina. This review discusses how peripheral positioning is connected to transcriptional regulation in yeasts. Tethering of reporter genes to the nuclear envelope was found to result in transcriptional silencing. Similarly, repression of the silent mating type loci and subtelomeric genes is influenced by their position close to the nuclear envelope. In contrast, active genes are bound by nucleoporins and inducible genes associate with the nuclear pore complex upon activation. Taken together, these results portray the nuclear envelope as a platform for transcriptional regulation, both through activation at nuclear pores and silencing at the nuclear envelope. PMID:24021962

  18. Artificial Immune System for Flight Envelope Estimation and Protection

    DTIC Science & Technology

    2014-12-31

    consists of two equally important components: the innate system and the adaptive system1. The former is an inherited system that functions as the... innate immune system is always active and responds immediately to any class of pathogen without distinction. On the other hand, the adaptive immune...are macrophages (MΦs), dendritic cells (DCs), T-cells, and B-cells. The MΦ and DC populations form what is known as phagocytes (part of the innate

  19. Creating a Lunar EVA Work Envelope

    NASA Technical Reports Server (NTRS)

    Griffin, Brand N.; Howard, Robert; Rajulu, Sudhakar; Smitherman, David

    2009-01-01

    A work envelope has been defined for weightless Extravehicular Activity (EVA) based on the Space Shuttle Extravehicular Mobility Unit (EMU), but there is no equivalent for planetary operations. The weightless work envelope is essential for planning all EVA tasks because it determines the location of removable parts, making sure they are within reach and visibility of the suited crew member. In addition, using the envelope positions the structural hard points for foot restraints that allow placing both hands on the job and provides a load path for reacting forces. EVA operations are always constrained by time. Tasks are carefully planned to ensure the crew has enough breathing oxygen, cooling water, and battery power. Planning first involves computers using a virtual work envelope to model tasks, next suited crew members in a simulated environment refine the tasks. For weightless operations, this process is well developed, but planetary EVA is different and no work envelope has been defined. The primary difference between weightless and planetary work envelopes is gravity. It influences anthropometry, horizontal and vertical mobility, and reaction load paths and introduces effort into doing "overhead" work. Additionally, the use of spacesuits other than the EMU, and their impacts on range of motion, must be taken into account. This paper presents the analysis leading to a concept for a planetary EVA work envelope with emphasis on lunar operations. There is some urgency in creating this concept because NASA has begun building and testing development hardware for the lunar surface, including rovers, habitats and cargo off-loading equipment. Just as with microgravity operations, a lunar EVA work envelope is needed to guide designers in the formative stages of the program with the objective of avoiding difficult and costly rework.

  20. Genetic diversity of koala retroviral envelopes.

    PubMed

    Xu, Wenqin; Gorman, Kristen; Santiago, Jan Clement; Kluska, Kristen; Eiden, Maribeth V

    2015-03-17

    Genetic diversity, attributable to the low fidelity of reverse transcription, recombination and mutation, is an important feature of infectious retroviruses. Under selective pressure, such as that imposed by superinfection interference, gammaretroviruses commonly adapt their envelope proteins to use alternative receptors to overcome this entry block. The first characterized koala retroviruses KoRV subgroup A (KoRV-A) were remarkable in their absence of envelope genetic variability. Once it was determined that KoRV-A was present in all koalas in US zoos, regardless of their disease status, we sought to isolate a KoRV variant whose presence correlated with neoplastic malignancies. More than a decade after the identification of KoRV-A, we isolated a second subgroup of KoRV, KoRV-B from koalas with lymphomas. The envelope proteins of KoRV-A and KoRV-B are sufficiently divergent to confer the ability to bind and employ distinct receptors for infection. We have now obtained a number of additional KoRV envelope variants. In the present studies we report these variants, and show that they differ from KoRV-A and KoRV-B envelopes in their host range and superinfection interference properties. Thus, there appears to be considerable variation among KoRVs envelope genes suggesting genetic diversity is a factor following the KoRV-A infection process.

  1. Cooling of neutron stars with diffusive envelopes

    NASA Astrophysics Data System (ADS)

    Beznogov, M. V.; Fortin, M.; Haensel, P.; Yakovlev, D. G.; Zdunik, J. L.

    2016-12-01

    We study the effects of heat blanketing envelopes of neutron stars on their cooling. To this aim, we perform cooling simulations using newly constructed models of the envelopes composed of binary ion mixtures (H-He, He-C, C-Fe) varying the mass of lighter ions (H, He or C) in the envelope. The results are compared with those calculated using the standard models of the envelopes which contain the layers of lighter (accreted) elements (H, He and C) on top of the Fe layer, varying the mass of accreted elements. The main effect is that the chemical composition of the envelopes influences their thermal conductivity and, hence, thermal insulation of the star. For illustration, we apply these results to estimate the internal temperature of the Vela pulsar and to study the cooling of neutron stars of ages of 105-106 yr at the photon cooling stage. The uncertainties of the cooling models associated with our poor knowledge of chemical composition of the heat insulating envelopes strongly complicate theoretical reconstruction of the internal structure of cooling neutron stars from observations of their thermal surface emission.

  2. The joke envelope: a neglected precursor of the psychic envelope concept in Freud's writing.

    PubMed

    Spero, Moshe Halevi

    2009-01-01

    The concepts of the primeval skin ego, psychic envelope, and related pre-ego containing and wrapping functions elaborated respectively by Esther Bick, Didier Anzieu, and Francis Tustin occupy an important position in contemporary psychoanalytic theory and clinical practice. The psychic envelope begins as a virtual mental protostructure ("proto" because it is not yet based on fully symbolized representations) that holds the budding mind together pending further developments. With maturity, the enveloping functions adopt symbolized, metaphoric form (for example, the aesthetic use of cloth, the analytic framework), but can regress to more concrete and pathological forms. The aforementioned authors based their ideas on a cluster of specific allusions to the idea of a psychic covering, barrier, or envelope in Freud's work. Yet they neglected one reference, hidden in Freud's analysis of the structure ofjokes and humor: the 'joke envelope"--die witzige Einkleidung. The present essay explores Freud's use of the term Einkleidung, including his intriguing idea that a joke requires three people whereas a dream does not and the fact that Freud nowhere speaks of a "dream envelope. "I take the "joke envelope" beyond its original context and posit a relationship between laughter and the early, normative traumas of breathing, crying, and loss, and the dawn of rhythmic envelopes that enable mentalization. Jokes and joking symbolically repeat the early rupture and rapture of breathing and self-other differentiation and the internalization of maternal containing and envelopment.

  3. A linkage between SmeIJK efflux pump, cell envelope integrity, and σE-mediated envelope stress response in Stenotrophomonas maltophilia.

    PubMed

    Huang, Yi-Wei; Liou, Rung-Shiuan; Lin, Yi-Tsung; Huang, Hsin-Hui; Yang, Tsuey-Ching

    2014-01-01

    Resistance nodulation division (RND) efflux pumps, such as the SmeIJK pump of Stenotrophomonas maltophilia, are known to contribute to the multidrug resistance in Gram-negative bacteria. However, some RND pumps are constitutively expressed even though no antimicrobial stresses occur, implying that there should be some physical implications for these RND pumps. In this study, the role of SmeIJK in antimicrobials resistance, envelope integrity, and σE-mediated envelope stress response (ESR) of S. maltophilia was assessed. SmeIJK was involved in the intrinsic resistance of S. maltophilia KJ to aminoglycosides and leucomycin. Compared with the wild-type KJ, the smeIJK deletion mutant exhibited growth retardation in the MH medium, an increased sensitivity to membrane-damaging agents (MDAs), as well as activation of an σE-mediated ESR. Moreover, the expression of smeIJK was further induced by sub-lethal concentrations of MDAs or surfactants in an σE-dependent manner. These data collectively suggested an alternative physiological role of smeIJK in cell envelope integrity maintenance and σE-mediated ESR beyond the efflux of antibiotics. Because of the necessity of the physiological role of SmeIJK in protecting S. maltophilia from the envelope stress, smeIJK is constitutively expressed, which, in turn, contributes the intrinsic resistance to aminoglycoside and leucomycin. This is the first demonstration of the linkage among RND-type efflux pump, cell envelope integrity, and σE-mediated ESR in S. maltophilia.

  4. Solitary Alfven wave envelopes and the modulational instability

    SciTech Connect

    Kennel, C.F.

    1987-06-01

    The derivative nonlinear Schroedinger equation describes the modulational instability of circularly polarized dispersive Alfven wave envelopes. It also may be used to determine the properties of finite amplitude localized stationary wave envelopes. Such envelope solitons exist only in conditions of modulational stability. This leaves open the question of whether, and if so, how, the modulational instability produces envelope solitons. 12 refs.

  5. Envelope Variants Circulating as Initial Neutralization Breadth Developed in Two HIV-Infected Subjects Stimulate Multiclade Neutralizing Antibodies in Rabbits

    PubMed Central

    Malherbe, Delphine C.; Pissani, Franco; Sather, D. Noah; Guo, Biwei; Pandey, Shilpi; Sutton, William F.; Stuart, Andrew B.; Robins, Harlan; Park, Byung; Krebs, Shelly J.; Schuman, Jason T.; Kalams, Spyros; Hessell, Ann J.

    2014-01-01

    ABSTRACT Identifying characteristics of the human immunodeficiency virus type 1 (HIV-1) envelope that are effective in generating broad, protective antibodies remains a hurdle to HIV vaccine design. Emerging evidence of the development of broad and potent neutralizing antibodies in HIV-infected subjects suggests that founder and subsequent progeny viruses may express unique antigenic motifs that contribute to this developmental pathway. We hypothesize that over the course of natural infection, B cells are programmed to develop broad antibodies by exposure to select populations of emerging envelope quasispecies variants. To test this hypothesis, we identified two unrelated subjects whose antibodies demonstrated increasing neutralization breadth against a panel of HIV-1 isolates over time. Full-length functional env genes were cloned longitudinally from these subjects from months after infection through 2.6 to 5.8 years of infection. Motifs associated with the development of breadth in published, cross-sectional studies were found in both subjects. We compared the immunogenicity of envelope vaccines derived from time points obtained during and after broadening of neutralization activity within these subjects. Rabbits were coimmunized four times with selected multiple gp160 DNAs and gp140-trimeric envelope proteins. The affinity of the polyclonal response increased as a function of boosting. The most rapid and persistent neutralization of multiclade tier 1 viruses was elicited by envelopes that were circulating in plasma at time points prior to the development of 50% neutralization breadth in both human subjects. The breadth elicited in rabbits was not improved by exposure to later envelope variants. These data have implications for vaccine development in describing a target time point to identify optimal envelope immunogens. IMPORTANCE Vaccine protection against viral infections correlates with the presence of neutralizing antibodies; thus, vaccine components capable

  6. Self-contained clothing system provides protection against hazardous environments

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Self-contained clothing system protects personnel against hazardous environments. The clothing has an environmental control system and a complete protection envelope consisting of an outer garment, inner garment, underwear, boots, gloves, and helmet.

  7. Morphologically complex protostellar envelopes : structure and kinematics

    NASA Astrophysics Data System (ADS)

    Tobin, John J.

    I present an in-depth study of protostars and their surrounding envelopes of dense gas and dust, using a multitude of observational methods to reveal new details of the star formation process. I use mid-infrared imaging from the Spitzer Space Telescope, combined with photometry spanning the near-infrared to millimeter wavelengths, to construct a model of the L1527 protostellar system. I modeled both the spectral energy distribution and resolved scattered light images to determine physical properties of the protostellar system. The nature of the apparent central point source in the Spitzer images was uncertain until high-resolution L-band imaging from the Gemini observatory resolved the point source into a disk in scattered light, having a radius of 200 AU. Protostellar envelopes are also often found to cast shadows against the 8 micron Galactic background in Spitzer imaging, enabling direct probes of envelope structure. The shadow images show that the dense envelopes around twenty-two Class 0 protostars are generally morphologically complex from 0.1 pc scales down to ˜1000 AU; they are often filamentary, and frequently non-axisymmetric. The observed envelope structure indicates a likely origin in turbulent cloud structure rather than a quasi-static/equilibrium formation. The complex envelope structure also may indicate an increased likelihood of fragmentation during collapse, forming close binaries. To further characterize these envelopes, I have observed them in the dense molecular gas tracers nthp and nht, both of which closely follow the 8 micron extinction morphology. The magnitude of the velocity gradients and envelope complexity on ˜10000 AU scales indicates that the velocity structure may reflect large-scale infall in addition to the often assumed rotation. Comparisons with three-dimensional filamentary and symmetric rotating collapse models reinforce the interpretation of velocities reflecting large-scale infall, showing that the structure of the envelope

  8. The cell envelope proteome of Aggregatibacter actinomycetemcomitans.

    PubMed

    Smith, K P; Fields, J G; Voogt, R D; Deng, B; Lam, Y-W; Mintz, K P

    2015-04-01

    The cell envelope of gram-negative bacteria serves a critical role in maintenance of cellular homeostasis, resistance to external stress, and host-pathogen interactions. Envelope protein composition is influenced by the physiological and environmental demands placed on the bacterium. In this study, we report a comprehensive compilation of cell envelope proteins from the periodontal and systemic pathogen Aggregatibacter actinomycetemcomitans VT1169, an afimbriated serotype b strain. The urea-extracted membrane proteins were identified by mass spectrometry-based shotgun proteomics. The membrane proteome, isolated from actively growing bacteria under normal laboratory conditions, included 648 proteins representing 27% of the predicted open reading frames in the genome. Bioinformatic analyses were used to annotate and predict the cellular location and function of the proteins. Surface adhesins, porins, lipoproteins, numerous influx and efflux pumps, multiple sugar, amino acid and iron transporters, and components of the type I, II and V secretion systems were identified. Periplasmic space and cytoplasmic proteins with chaperone function were also identified. A total of 107 proteins with unknown function were associated with the cell envelope. Orthologs of a subset of these uncharacterized proteins are present in other bacterial genomes, whereas others are found exclusively in A. actinomycetemcomitans. This knowledge will contribute to elucidating the role of cell envelope proteins in bacterial growth and survival in the oral cavity.

  9. Adaptive Spectral Envelope Estimation for Doppler Ultrasound.

    PubMed

    Kathpalia, Aditi; Karabiyik, Yucel; Eik-Nes, Sturla; Tegnander, Eva; Ekroll, Ingvild; Kiss, Gabriel; Torp, Hans

    2016-07-07

    Estimation of accurate maximum velocities and spectral envelope in ultrasound Doppler blood flow spectrograms are both essential for clinical diagnostic purposes. However, obtaining accurate maximum velocity is not straightforward due to intrinsic spectral broadening and variance in the power spectrum estimate. The method proposed in this work for maximum velocity point detection has been developed by modifying an existing method - Signal Noise Slope Intersection (SNSI), incorporating in it steps from an altered version of another method called Geometric Method (GM). Adaptive noise estimation from the spectrogram ensures that a smooth spectral envelope is obtained post detection of these maximum velocity points. The method has been tested on simulated Doppler signal with scatterers possessing a parabolic flow velocity profile constant in time, steady and pulsatile string phantom recordings as well as in vivo recordings from uterine, umbilical, carotid and subclavian arteries. Results from simulation experiments indicate a bias of less than 2.5% in maximum velocities when estimated for a range of peak velocities, Doppler angles and SNR levels. Standard deviation in the envelope is low - less than 2% in case of experiments done by varying the peak velocity and Doppler angle for steady phantom and simulated flow; and also less than 2% in case of experiments done by varying SNR but keeping constant flow conditions for in vivo and simulated flow. Low variability in the envelope makes the prospect of using the envelope for automated blood flow measurements possible and is illustrated for the case of Pulsatility Index estimation in uterine and umbilical arteries.

  10. Featured Image: Orbiting Stars Share an Envelope

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-03-01

    This beautiful series of snapshots from a simulation (click for a better look!) shows what happens when two stars in a binary system become enclosed in the same stellar envelope. In this binary system, one of the stars has exhausted its hydrogen fuel and become a red giant, complete with an expanding stellar envelope composed of hydrogen and helium. Eventually, the envelope expands so much that the companion star falls into it, where it releases gravitational potential energy into the common envelope. A team led by Sebastian Ohlmann (Heidelberg Institute for Theoretical Studies and University of Wrzburg) recently performed hydrodynamic simulations of this process. Ohlmann and collaborators discovered that the energy release eventually triggers large-scale flow instabilities, which leads to turbulence within the envelope. This process has important consequences for how these systems next evolve (for instance, determining whether or not a supernova occurs!). You can check out the authors video of their simulated stellar inspiral below, or see their paper for more images and results from their study.CitationSebastian T. Ohlmann et al 2016 ApJ 816 L9. doi:10.3847/2041-8205/816/1/L9

  11. COMPLEX STRUCTURE IN CLASS 0 PROTOSTELLAR ENVELOPES

    SciTech Connect

    Tobin, John J.; Hartmann, Lee; Looney, Leslie W.; Chiang, Hsin-Fang

    2010-04-01

    We use archived Infrared Array Camera images from the Spitzer Space Telescope to show that many Class 0 protostars exhibit complex, irregular, and non-axisymmetric structure within their dusty envelopes. Our 8 {mu}m extinction maps probe some of the densest regions in these protostellar envelopes. Many of the systems are observed to have highly irregular and non-axisymmetric morphologies on scales {approx}>1000 AU, with a quarter of the sample exhibiting filamentary or flattened dense structures. Complex envelope structure is observed in regions spatially distinct from outflow cavities, and the densest structures often show no systematic alignment perpendicular to the cavities. These results indicate that mass ejection is not responsible for much of the irregular morphologies we detect; rather, we suggest that the observed envelope complexity is mostly the result of collapse from protostellar cores with initially non-equilibrium structures. The striking non-axisymmetry in many envelopes could provide favorable conditions for the formation of binary systems. We also note that protostars in the sample appear to be formed preferentially near the edges of clouds or bends in filaments, suggesting formation by gravitational focusing.

  12. Mixing Envelope D Sludge with LAW Intermediate Products with and without Glass Formers

    SciTech Connect

    Hansen, E.K.

    2001-09-21

    The Department of Energy (DOE) Office of River Protection is in the process of designing a waste treatment system to process the Hanford Reservation High Level Waste (HLW). Envelope D sludge slurries will be blended with the concentrated Cs/Ts eluates, and the Sr/TRU intermediates separated from Envelope A, B, and C feeds. This study produced two washed simulated sludges (representing tanks 241-AZ-101 and 241-AZ-102 sludge), a Sr/TRU washed precipitate produced from tank 241-AN-107 simulant, and a concentrated blended eluate simulant based upon eluates from processing 241-AZ-102 supernate.

  13. Ultradonut topology of the nuclear envelope

    PubMed Central

    Torbati, Mehdi; Lele, Tanmay P.; Agrawal, Ashutosh

    2016-01-01

    The nuclear envelope is a unique topological structure formed by lipid membranes in eukaryotic cells. Unlike other membrane structures, the nuclear envelope comprises two concentric membrane shells fused at numerous sites with toroid-shaped pores that impart a “geometric” genus on the order of thousands. Despite the intriguing architecture and vital biological functions of the nuclear membranes, how they achieve and maintain such a unique arrangement remains unknown. Here, we used the theory of elasticity and differential geometry to analyze the equilibrium shape and stability of this structure. Our results show that modest in- and out-of-plane stresses present in the membranes not only can define the pore geometry, but also provide a mechanism for destabilizing membranes beyond a critical size and set the stage for the formation of new pores. Our results suggest a mechanism wherein nanoscale buckling instabilities can define the global topology of a nuclear envelope-like structure. PMID:27647910

  14. Drug design from the cryptic inhibitor envelope.

    PubMed

    Lee, Chul-Jin; Liang, Xiaofei; Wu, Qinglin; Najeeb, Javaria; Zhao, Jinshi; Gopalaswamy, Ramesh; Titecat, Marie; Sebbane, Florent; Lemaitre, Nadine; Toone, Eric J; Zhou, Pei

    2016-02-25

    Conformational dynamics plays an important role in enzyme catalysis, allosteric regulation of protein functions and assembly of macromolecular complexes. Despite these well-established roles, such information has yet to be exploited for drug design. Here we show by nuclear magnetic resonance spectroscopy that inhibitors of LpxC--an essential enzyme of the lipid A biosynthetic pathway in Gram-negative bacteria and a validated novel antibiotic target--access alternative, minor population states in solution in addition to the ligand conformation observed in crystal structures. These conformations collectively delineate an inhibitor envelope that is invisible to crystallography, but is dynamically accessible by small molecules in solution. Drug design exploiting such a hidden inhibitor envelope has led to the development of potent antibiotics with inhibition constants in the single-digit picomolar range. The principle of the cryptic inhibitor envelope approach may be broadly applicable to other lead optimization campaigns to yield improved therapeutics.

  15. Drug design from the cryptic inhibitor envelope

    PubMed Central

    Lee, Chul-Jin; Liang, Xiaofei; Wu, Qinglin; Najeeb, Javaria; Zhao, Jinshi; Gopalaswamy, Ramesh; Titecat, Marie; Sebbane, Florent; Lemaitre, Nadine; Toone, Eric J.; Zhou, Pei

    2016-01-01

    Conformational dynamics plays an important role in enzyme catalysis, allosteric regulation of protein functions and assembly of macromolecular complexes. Despite these well-established roles, such information has yet to be exploited for drug design. Here we show by nuclear magnetic resonance spectroscopy that inhibitors of LpxC—an essential enzyme of the lipid A biosynthetic pathway in Gram-negative bacteria and a validated novel antibiotic target—access alternative, minor population states in solution in addition to the ligand conformation observed in crystal structures. These conformations collectively delineate an inhibitor envelope that is invisible to crystallography, but is dynamically accessible by small molecules in solution. Drug design exploiting such a hidden inhibitor envelope has led to the development of potent antibiotics with inhibition constants in the single-digit picomolar range. The principle of the cryptic inhibitor envelope approach may be broadly applicable to other lead optimization campaigns to yield improved therapeutics. PMID:26912110

  16. Envelope Solitons in Acoustically Dispersive Vitreous Silica

    NASA Technical Reports Server (NTRS)

    Cantrell, John H.; Yost, William T.

    2012-01-01

    Acoustic radiation-induced static strains, displacements, and stresses are manifested as rectified or dc waveforms linked to the energy density of an acoustic wave or vibrational mode via the mode nonlinearity parameter of the material. An analytical model is developed for acoustically dispersive media that predicts the evolution of the energy density of an initial waveform into a series of energy solitons that generates a corresponding series of radiation-induced static strains (envelope solitons). The evolutionary characteristics of the envelope solitons are confirmed experimentally in Suprasil W1 vitreous silica. The value (-11.9 plus or minus 1.43) for the nonlinearity parameter, determined from displacement measurements of the envelope solitons via a capacitive transducer, is in good agreement with the value (-11.6 plus or minus 1.16) obtained independently from acoustic harmonic generation measurements. The agreement provides strong, quantitative evidence for the validity of the model.

  17. [NESPRINS--nuclear envelope proteins ensuring integrity].

    PubMed

    Pershina, E G; Morozova, K N; Kiseleva, E V

    2014-01-01

    This review describes the nesprins (nuclear envelope spectrin-repeat proteins), which are recently discovered family of nuclear envelope proteins. These proteins play an important role in maintaining the cellular architecture and establish the link between the nucleus and other sub-cellular compartments. Many tissue-specific diseases including lipodystrophies, hearing loss, cardiac and skeletal myopathies are associated with nesprins mutations. These proteins comprise of multiple tissue specific isoforms which contain spectrin repeats providing interaction of nesprins with other nuclear membrane proteins, cytoskeleton and intranuclear matrix. We summarize recent findings and suggestions about nesprins structural organization and function inside the cell. Human diseases caused by abnormal nesprins expression are also described.

  18. The photodissociation of CO in circumstellar envelopes

    NASA Technical Reports Server (NTRS)

    Mamon, G. A.; Glassgold, A. E.; Huggins, P. J.

    1988-01-01

    The CO photodissociation rate for the unshielded ISM is calculated using recent laboratory results which confirm that photodissociation occurs by way of line absorption. A value of 2.0 x 10 to the -10th/s, an order of magnitude higher than the rate used in the past, is obtained. The new rate and a treatment of the radiative transfer and shielding are used to develop a theory for the CO abundance in the circumstellar envelopes of cool, evolved stars, and results are presented on the spatial variation of CO, C, and C(+). It is shown that these distributions play important roles in determining the observational properties of circumstellar envelopes.

  19. Consumer access to utility billing envelopes

    SciTech Connect

    Anglin, M.K.

    1984-09-13

    Billing envelope inserts are a medium of advertising used by utilities for a variety of purposes, from encouraging conservation to expressing political opinions. Recently, consumer groups have begun to assert a right of access to the same medium. A constitutional right of reply has been advocated. Commissions have found regulatory authority to direct companies to provide access on the basis of several different theories. At least two states have passed legislation permitting consumer groups to use bill inserts to solicit members and contributions. When examined, these developments reveal a trend of granting organizations access to utility billing envelopes.

  20. Perception and coding of envelopes in weakly electric fishes.

    PubMed

    Stamper, Sarah A; Fortune, Eric S; Chacron, Maurice J

    2013-07-01

    Natural sensory stimuli have a rich spatiotemporal structure and can often be characterized as a high frequency signal that is independently modulated at lower frequencies. This lower frequency modulation is known as the envelope. Envelopes are commonly found in a variety of sensory signals, such as contrast modulations of visual stimuli and amplitude modulations of auditory stimuli. While psychophysical studies have shown that envelopes can carry information that is essential for perception, how envelope information is processed in the brain is poorly understood. Here we review the behavioral salience and neural mechanisms for the processing of envelopes in the electrosensory system of wave-type gymnotiform weakly electric fishes. These fish can generate envelope signals through movement, interactions of their electric fields in social groups or communication signals. The envelopes that result from the first two behavioral contexts differ in their frequency content, with movement envelopes typically being of lower frequency. Recent behavioral evidence has shown that weakly electric fish respond in robust and stereotypical ways to social envelopes to increase the envelope frequency. Finally, neurophysiological results show how envelopes are processed by peripheral and central electrosensory neurons. Peripheral electrosensory neurons respond to both stimulus and envelope signals. Neurons in the primary hindbrain recipient of these afferents, the electrosensory lateral line lobe (ELL), exhibit heterogeneities in their responses to stimulus and envelope signals. Complete segregation of stimulus and envelope information is achieved in neurons in the target of ELL efferents, the midbrain torus semicircularis (Ts).

  1. Structural changes of envelope proteins during alphavirus fusion

    SciTech Connect

    Li, Long; Jose, Joyce; Xiang, Ye; Kuhn, Richard J.; Rossmann, Michael G.

    2010-12-08

    Alphaviruses are enveloped RNA viruses that have a diameter of about 700 {angstrom} and can be lethal human pathogens. Entry of virus into host cells by endocytosis is controlled by two envelope glycoproteins, E1 and E2. The E2-E1 heterodimers form 80 trimeric spikes on the icosahedral virus surface, 60 with quasi-three-fold symmetry and 20 coincident with the icosahedral three-fold axes arranged with T = 4 quasi-symmetry. The E1 glycoprotein has a hydrophobic fusion loop at one end and is responsible for membrane fusion. The E2 protein is responsible for receptor binding and protects the fusion loop at neutral pH. The lower pH in the endosome induces the virions to undergo an irreversible conformational change in which E2 and E1 dissociate and E1 forms homotrimers, triggering fusion of the viral membrane with the endosomal membrane and then releasing the viral genome into the cytoplasm. Here we report the structure of an alphavirus spike, crystallized at low pH, representing an intermediate in the fusion process and clarifying the maturation process. The trimer of E2-E1 in the crystal structure is similar to the spikes in the neutral pH virus except that the E2 middle region is disordered, exposing the fusion loop. The amino- and carboxy-terminal domains of E2 each form immunoglobulin-like folds, consistent with the receptor attachment properties of E2.

  2. SAFEGUARDS ENVELOPE: PREVIOUS WORK AND EXAMPLES

    SciTech Connect

    Richard Metcalf; Aaron Bevill; William Charlton; Robert Bean

    2008-07-01

    The future expansion of nuclear power will require not just electricity production but fuel cycle facilities such as fuel fabrication and reprocessing plants. As large reprocessing facilities are built in various states, they must be built and operated in a manner to minimize the risk of nuclear proliferation. Process monitoring has returned to the spotlight as an added measure that can increase confidence in the safeguards of special nuclear material (SNM). Process monitoring can be demonstrated to lengthen the allowable inventory period by reducing accountancy requirements, and to reduce the false positive indications. The next logical step is the creation of a Safeguards Envelope, a set of operational parameters and models to maximize anomaly detection and inventory period by process monitoring while minimizing operator impact and false positive rates. A brief example of a rudimentary Safeguards Envelope is presented, and shown to detect synthetic diversions overlaying a measured processing plant data set. This demonstration Safeguards Envelope is shown to increase the confidence that no SNM has been diverted with minimal operator impact, even though it is based on an information sparse environment. While the foundation on which a full Safeguards Envelope can be built has been presented in historical demonstrations of process monitoring, several requirements remain yet unfulfilled. Future work will require reprocessing plant transient models, inclusion of “non-traditional” operating data, and exploration of new methods of identifying subtle events in transient processes.

  3. The Methodology of Data Envelopment Analysis.

    ERIC Educational Resources Information Center

    Sexton, Thomas R.

    1986-01-01

    The methodology of data envelopment analysis, (DEA) a linear programming-based method, is described. Other procedures often used for measuring relative productive efficiency are discussed in relation to DEA, including ratio analysis and multiple regression analysis. The DEA technique is graphically illustrated for only two inputs and one output.…

  4. Ultraviolet Opacity and Fluorescence in Supernova Envelopes

    NASA Technical Reports Server (NTRS)

    Li, Hongwei; McCray, Richard

    1996-01-01

    By the time the expanding envelope of a Type 2 supernova becomes transparent in the optical continuum, most of the gamma-ray luminosity produced by radioactive Fe/Co/Ni clumps propagates into the hydrogen/helium envelope and is deposited there, if at all. The resulting fast electrons excite He 1 and H 1, the two- photon continua of which are the dominant internal sources of ultraviolet radiation. The UV radiation is blocked by scattering in thousands of resonance lines of metals and converted by fluorescence into optical and infrared emission lines that escape freely. We describe results of Monte Carlo calculations that simulate non-LTE scattering and fluorescence in more than five million allowed lines of Ca, Sc, Ti, V, Cr, Mn, Fe, Co, and Ni. For a model approximating conditions in the envelope of SN 1987A, the calculated emergent spectrum resembles the observed one. For the first 2 yr after explosion, the ultraviolet radiation (lambda less than or approximately equals 3000) is largely blocked and converted into a quasi continuum of many thousands of weak optical and infrared emission lines and some prominent emission features, such as the Ca 2 lambdalambda8600 triplet. Later, as the envelope cools and expands, it becomes more transparent, and an increasing fraction of the luminosity emerges in the UV band.

  5. Discriminating Dysarthria Type from Envelope Modulation Spectra

    ERIC Educational Resources Information Center

    Liss, Julie M.; LeGendre, Sue; Lotto, Andrew J.

    2010-01-01

    Purpose: Previous research demonstrated the ability of temporally based rhythm metrics to distinguish among dysarthrias with different prosodic deficit profiles (J. M. Liss et al., 2009). The authors examined whether comparable results could be obtained by an automated analysis of speech envelope modulation spectra (EMS), which quantifies the…

  6. 14 CFR 23.333 - Flight envelope.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... any combination of airspeed and load factor on and within the boundaries of a flight envelope (similar... altitudes between sea level and 20,000 feet. The gust velocity may be reduced linearly from 50 f.p.s. at 20... considered at altitudes between sea level and 20,000 feet. The gust velocity may be reduced linearly from...

  7. 14 CFR 23.333 - Flight envelope.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... any combination of airspeed and load factor on and within the boundaries of a flight envelope (similar... altitudes between sea level and 20,000 feet. The gust velocity may be reduced linearly from 50 f.p.s. at 20... considered at altitudes between sea level and 20,000 feet. The gust velocity may be reduced linearly from...

  8. Ozone Reductions Using Residential Building Envelopes

    SciTech Connect

    Walker, Iain S.; Sherman, Max; Nazaroff, William W.

    2009-02-01

    Ozone is an air pollutant with that can have significant health effects and a significant source of ozone in some regions of California is outdoor air. Because people spend the vast majority of their time indoors, reduction in indoor levels of ozone could lead to improved health for many California residents. Ozone is removed from indoor air by surface reactions and can also be filtered by building envelopes. The magnitude of the envelope impact depends on the specific building materials that the air flows over and the geometry of the air flow paths through the envelope that can be changes by mechanical ventilation operation. The 2008 Residential Building Standards in California include minimum requirements for mechanical ventilation by referencing ASHRAE Standard 62.2. This study examines the changes in indoor ozone depending on the mechanical ventilation system selected to meet these requirements. This study used detailed simulations of ventilation in a house to examine the impacts of different ventilation systems on indoor ozone concentrations. The simulation results showed that staying indoors reduces exposure to ozone by 80percent to 90percent, that exhaust ventilation systems lead to lower indoor ozone concentrations, that opening of windows should be avoided at times of high outdoor ozone, and that changing the time at which mechanical ventilation occurs has the ability to halve exposure to ozone. Future work should focus on the products of ozone reactions in the building envelope and the fate of these products with respect to indoor exposures.

  9. Right to Light: Ralph Knowles's Solar Envelope.

    ERIC Educational Resources Information Center

    Morton, David

    1979-01-01

    At the University of Southern California solar-access design research project, Barry Knowles and students have devised a solar envelope: the largest volumetric container over a land parcel that allows solar access to all adjacent neighbors within useful time constraints. (Author/MLF)

  10. CO line emission from circumstellar envelopes

    NASA Astrophysics Data System (ADS)

    Teyssier, D.; Hernandez, R.; Bujarrabal, V.; Yoshida, H.; Phillips, T. G.

    2006-04-01

    Aims.We present the results of a multi-transition CO observational program conducted on a sample of AGB and post-AGB stars envelopes. We have collected maps and single pointing observations of these envelopes in 5 rotational transitions ranging from J = 1-0 to J = 6-5, including in particular new observations of the CO line at 691 GHz at the CSO. The use of such a set of mm and submm CO line on stellar envelopes is rare and limited to the work of some authors on IRC+10216. Methods: .Using a model for the CO emission of an AGB circumstellar envelope, in combination with a standard LVG approach, we have conducted a systematic modelling analysis using the whole set of CO data collected for a sample of 12 sources. We simultaneously fit all five transitions, taking into account the spatial information provided by the maps. Results: .We find mass-loss rates in the range 1 × 10-7 to 4 × 10-4 M_⊙/yr, and envelope temperatures ranging from 20 K to 1000 K at a radius of 1016 cm. There seem to be a general anti-correlation between mass loss rates and temperature, the high mass loss rate AGBs having low temperatures, and vice versa. We show that most AGB data can be fitted using a constant mass loss rate, at least within the calibration uncertainties associated with the data collected at different frequencies. For some cases though (e.g. CIT 6, R Hya, χ Cyg), a change in the mass loss rate history needs to be invoked to reconcile data at low- and high-J, a scenario already mentioned by several authors to explain observations of WX Psc.

  11. The Circumstellar Envelope of IRC +10216.

    NASA Astrophysics Data System (ADS)

    Keady, John Joseph

    1982-03-01

    Using recently obtained spatial and spectral line data on the circumstellar envelope of IRC +10216, we have attempted to semi-empirically probe the conditions in this envelope. The computational techniques utilized in our analysis accurately incorporate the effects of geometrical extension and velocity fields on the radiative transfer. We have also attempted to account for the non-equilibrium expected in the vibrational level populations of the gas phase species. Our modelling of the spatial distribution of the dust-produced circumstellar radiation field at 5 (mu)m and 11 (mu)m indicates that dust may be condensing in the circumstellar envelope. The dominant opacity source in our calculations, amorphous carbon, also seems to provide sufficient far-infrared flux. Modelling of the SiC emission feature confirms previous results that suggest a nonuniform particle-shape distribution for the SiC. We can produce multi-component absorption lines, very similar to the 2 (mu)m CO first overtone lines seen in IRC +10216, with continuous distributions of material. The requirement is regions of relatively low acceleration. Modelling of our high resolution, high signal-to-noise observations of the CO fundamental and first overtone indicates a mass -loss rate of 1.5(10('-4)) M(,(CIRCLE))/yr. Our calculations to date indicate that the gas reaches terminal velocity between 10 and 20 R(,*). The envelope mass within 100 R(,*) is 3(10('-2)) M(,(CIRCLE)), with the ratio (by mass) of dust to gas being 10('-3). The assumption of a constant mass-loss rate implies an envelope mass of (TURN)1 M(,(CIRCLE)) within 5000 R(,*). The computational techniques utilized are sufficiently adaptable and economical so that considerable future refinement of the modelling is possible.

  12. Adaptive Spectral Envelope Estimation for Doppler Ultrasound.

    PubMed

    Kathpalia, Aditi; Karabiyik, Yucel; Eik-Nes, Sturla H; Tegnander, Eva; Ekroll, Ingvild Kinn; Kiss, Gabriel; Torp, Hans

    2016-11-01

    Estimation of accurate maximum velocities and spectral envelope in ultrasound Doppler blood flow spectrograms are both essential for clinical diagnostic purposes. However, obtaining accurate maximum velocity is not straightforward due to intrinsic spectral broadening and variance in the power spectrum estimate. The method proposed in this paper for maximum velocity point detection has been developed by modifying an existing method-signal noise slope intersection, incorporating in it steps from an altered version of another method called geometric method. Adaptive noise estimation from the spectrogram ensures that a smooth spectral envelope is obtained postdetection of these maximum velocity points. The method has been tested on simulated Doppler signal with scatterers possessing a parabolic flow velocity profile constant in time, steady and pulsatile string phantom recordings, as well as in vivo recordings from uterine, umbilical, carotid, and subclavian arteries. The results from simulation experiments indicate a bias of less than 2.5% in maximum velocities when estimated for a range of peak velocities, Doppler angles, and SNR levels. Standard deviation in the envelope is low-less than 2% in the case of experiments done by varying the peak velocity and Doppler angle for steady phantom and simulated flow, and also less than 2% in the case of experiments done by varying SNR but keeping constant flow conditions for in vivo and simulated flow. Low variability in the envelope makes the prospect of using the envelope for automated blood flow measurements possible and is illustrated for the case of pulsatility index estimation in uterine and umbilical arteries.

  13. The envelope-based cyclic periodogram

    NASA Astrophysics Data System (ADS)

    Borghesani, P.

    2015-06-01

    Cyclostationary analysis has proven effective in identifying signal components for diagnostic purposes. A key descriptor in this framework is the cyclic power spectrum, traditionally estimated by the averaged cyclic periodogram and the smoothed cyclic periodogram. A lengthy debate about the best estimator finally found a solution in a cornerstone work by Antoni, who proposed a unified form for the two families, thus allowing a detailed statistical study of their properties. Since then, the focus of cyclostationary research has shifted towards algorithms, in terms of computational efficiency and simplicity of implementation. Traditional algorithms have proven computationally inefficient and the sophisticated "cyclostationary" definition of these estimators slowed their spread in the industry. The only attempt to increase the computational efficiency of cyclostationary estimators is represented by the cyclic modulation spectrum. This indicator exploits the relationship between cyclostationarity and envelope analysis. The link with envelope analysis allows a leap in computational efficiency and provides a "way in" for the understanding by industrial engineers. However, the new estimator lies outside the unified form described above and an unbiased version of the indicator has not been proposed. This paper will therefore extend the analysis of envelope-based estimators of the cyclic spectrum, proposing a new approach to include them in the unified form of cyclostationary estimators. This will enable the definition of a new envelope-based algorithm and the detailed analysis of the properties of the cyclic modulation spectrum. The computational efficiency of envelope-based algorithms will be also discussed quantitatively for the first time in comparison with the averaged cyclic periodogram. Finally, the algorithms will be validated with numerical and experimental examples.

  14. Validating predictions from climate envelope models

    USGS Publications Warehouse

    Watling, J.; Bucklin, D.; Speroterra, C.; Brandt, L.; Cabal, C.; Romañach, Stephanie S.; Mazzotti, Frank J.

    2013-01-01

    Climate envelope models are a potentially important conservation tool, but their ability to accurately forecast species’ distributional shifts using independent survey data has not been fully evaluated. We created climate envelope models for 12 species of North American breeding birds previously shown to have experienced poleward range shifts. For each species, we evaluated three different approaches to climate envelope modeling that differed in the way they treated climate-induced range expansion and contraction, using random forests and maximum entropy modeling algorithms. All models were calibrated using occurrence data from 1967–1971 (t1) and evaluated using occurrence data from 1998–2002 (t2). Model sensitivity (the ability to correctly classify species presences) was greater using the maximum entropy algorithm than the random forest algorithm. Although sensitivity did not differ significantly among approaches, for many species, sensitivity was maximized using a hybrid approach that assumed range expansion, but not contraction, in t2. Species for which the hybrid approach resulted in the greatest improvement in sensitivity have been reported from more land cover types than species for which there was little difference in sensitivity between hybrid and dynamic approaches, suggesting that habitat generalists may be buffered somewhat against climate-induced range contractions. Specificity (the ability to correctly classify species absences) was maximized using the random forest algorithm and was lowest using the hybrid approach. Overall, our results suggest cautious optimism for the use of climate envelope models to forecast range shifts, but also underscore the importance of considering non-climate drivers of species range limits. The use of alternative climate envelope models that make different assumptions about range expansion and contraction is a new and potentially useful way to help inform our understanding of climate change effects on species.

  15. The Psp system of Mycobacterium tuberculosis integrates envelope stress-sensing and envelope-preserving functions.

    PubMed

    Datta, Pratik; Ravi, Janani; Guerrini, Valentina; Chauhan, Rinki; Neiditch, Matthew B; Shell, Scarlet S; Fortune, Sarah M; Hancioglu, Baris; Igoshin, Oleg A; Gennaro, Maria Laura

    2015-08-01

    The bacterial envelope integrates essential stress-sensing and adaptive functions; thus, envelope-preserving functions are important for survival. In Gram-negative bacteria, envelope integrity during stress is maintained by the multi-gene Psp response. Mycobacterium tuberculosis was thought to lack the Psp system since it encodes only pspA and no other psp ortholog. Intriguingly, pspA maps downstream from clgR, which encodes a transcription factor regulated by the MprAB-σ(E) envelope-stress-signaling system. clgR inactivation lowered ATP concentration during stress and protonophore treatment-induced clgR-pspA expression, suggesting that these genes express Psp-like functions. We identified a four-gene set - clgR, pspA (rv2744c), rv2743c, rv2742c - that is regulated by clgR and in turn regulates ClgR activity. Regulatory and protein-protein interactions within the set and a requirement of the four genes for functions associated with envelope integrity and surface-stress tolerance indicate that a Psp-like system has evolved in mycobacteria. Among Actinobacteria, the four-gene module occurred only in tuberculous mycobacteria and was required for intramacrophage growth, suggesting links between its function and mycobacterial virulence. Additionally, the four-gene module was required for MprAB-σ(E) stress-signaling activity. The positive feedback between envelope-stress-sensing and envelope-preserving functions allows sustained responses to multiple, envelope-perturbing signals during chronic infection, making the system uniquely suited to tuberculosis pathogenesis.

  16. Nuclear membrane: nuclear envelope PORosity in fission yeast meiosis.

    PubMed

    Sazer, Shelley

    2010-11-09

    The fission yeast Schizosaccharomyces pombe undergoes closed mitosis but 'virtual nuclear envelope breakdown' at anaphase of meiosis II, in which the nuclear envelope is structurally closed but functionally open.

  17. Thermodynamics and fluid dynamics of the double shell (envelope) house

    SciTech Connect

    Reno, V.

    1980-01-01

    The concepts of the envelope house are summarized and a systems approach to the house heat energy flows is presented. Some basic principles of physics in the area of thermodynamic conduction are discussed in relation to the envelope concept. (MHR)

  18. Kid-mediated chromosome compaction ensures proper nuclear envelope formation.

    PubMed

    Ohsugi, Miho; Adachi, Kenjiro; Horai, Reiko; Kakuta, Shigeru; Sudo, Katsuko; Kotaki, Hayato; Tokai-Nishizumi, Noriko; Sagara, Hiroshi; Iwakura, Yoichiro; Yamamoto, Tadashi

    2008-03-07

    Toward the end of mitosis, neighboring chromosomes gather closely to form a compact cluster. This is important for reassembling the nuclear envelope around the entire chromosome mass but not individual chromosomes. By analyzing mice and cultured cells lacking the expression of chromokinesin Kid/kinesin-10, we show that Kid localizes to the boundaries of anaphase and telophase chromosomes and contributes to the shortening of the anaphase chromosome mass along the spindle axis. Loss of Kid-mediated anaphase chromosome compaction often causes the formation of multinucleated cells, specifically at oocyte meiosis II and the first couple of mitoses leading to embryonic death. In contrast, neither male meiosis nor somatic mitosis after the morula-stage is affected by Kid deficiency. These data suggest that Kid-mediated anaphase/telophase chromosome compaction prevents formation of multinucleated cells. This protection is especially important during the very early stages of development, when the embryonic cells are rich in ooplasm.

  19. The action of three antiseptics/disinfectants against enveloped and non-enveloped viruses.

    PubMed

    Wood, A; Payne, D

    1998-04-01

    The antiviral action of chloroxylenol, benzalkonium chloride and cetrimide/chlorhexidine was assessed against a range of enveloped and non-enveloped human viruses using a suspension test method. Viral suspensions of 10(6)-10(7) pfu/TCID50 or sfu were prepared in each of the antiseptic/disinfectant solutions in the presence of a bovine serum/yeast extract mixture to simulate 'dirty conditions'. During incubation, aliquots were removed at predetermined timepoints up to 10 min to assess the kinetics of inactivation. Results indicate that all products were effective in inactivating the enveloped viruses herpes simplex virus type 1 and human immunodeficiency virus type 1, whilst being ineffective in inactivating human coronavirus, also enveloped, and the non-enveloped viruses. The exception to this was the benzalkonium chloride-based product (Dettol Hospital Concentrate) which was active against the non-enveloped human coxsackie virus. Four antiseptic/disinfectant solutions with chloroxylenol, benzalkonium chloride, cetrimide/chlorhexidine and povidone-iodine were also assessed for antiviral effect against human immunodeficiency virus in the presence of whole human blood. All four solutions proved to be effective within 1 min despite the cytotoxic nature of the compounds to the detection system.

  20. Solar Effective Envelope Design Advisor (SEEDA)

    NASA Astrophysics Data System (ADS)

    Mahaek, Ekkachai

    The lack of effort by mainstream architects in integrating energy-efficient strategies in architectural designing is due to the complexity in a building's energy conscious concepts and theories, the difficulties to visualize and quantify energy consumption, and the late implementing of energy consumption analysis in the conventional design process. This task would be accomplishing by a building system's engineer where results might be determined only after the basic architectural design has been completed. An effective simple tool and method should then be available to assist architects in building's energy-efficient designing at the beginning of the design. The building's energy consumption is directly and mainly influenced by the relationship of the sun, site, and its building configuration. The solar radiations will first impact on the building's envelope, which will have a direct effect on the amount of energy a building will consume. If an architect can define or map the intensity of solar energy on the site's buildable volume, and use this information to determine the levels of solar insolation, a more energy efficient building form can be proposed. This research hypothesis has shared the fundamental techniques of the Solar Envelope projection by Professor Ralph Knowles [Knowles, 1981] of the University of Southern California. However a different approach is taken by including the influence of regional restrictions and the surrounding buildings' shadows when projecting of solar volumes and solar envelope. The research methodology will discuss the development of a computer-based approach to develop a three-dimensional architectural form based on an insolation map related to the design site. The prototype computer program is referred as the Solar Effective Envelope Design Advisor (SEEDA). The solar insolation volume of the site is determined by integrating three types of computer-generated models include the Buildable Volume model based on design constraints

  1. 200 Area Deactivation Project Facilities Authorization Envelope Document

    SciTech Connect

    DODD, E.N.

    2000-03-28

    Project facilities as required by HNF-PRO-2701, Authorization Envelope and Authorization Agreement. The Authorization Agreements (AA's) do not identify the specific set of environmental safety and health requirements that are applicable to the facility. Therefore, the facility Authorization Envelopes are defined here to identify the applicable requirements. This document identifies the authorization envelopes for the 200 Area Deactivation.

  2. Analysis of Building Envelope Construction in 2003 CBECS

    SciTech Connect

    Winiarski, David W.; Halverson, Mark A.; Jiang, Wei

    2007-06-01

    The purpose of this analysis is to determine "typical" building envelope characteristics for buildings built after 1980. We address three envelope components in this paper - roofs, walls, and window area. These typical building envelope characteristics were used in the development of DOE’s Reference Buildings .

  3. Application of the Envelope Difference Index to Spectrally Sparse Speech

    ERIC Educational Resources Information Center

    Souza, Pamela; Hoover, Eric; Gallun, Frederick

    2012-01-01

    Purpose: Amplitude compression is a common hearing aid processing strategy that can improve speech audibility and loudness comfort but also has the potential to alter important cues carried by the speech envelope. In previous work, a measure of envelope change, the Envelope Difference Index (EDI; Fortune, Woodruff, & Preves, 1994), was moderately…

  4. Hydrogen sulfide in a circumstellar envelope

    NASA Technical Reports Server (NTRS)

    Ukita, N.; Morris, M.

    1983-01-01

    A search for hydrogen sulfide in the cool circumstellar envelopes of 25 stars was made using the 1(10)-1(01) rotational line at 1.8 mm. It was detected in the bipolar nebula/OH maser OH231.8+4.2, an object having a high rate of mass loss. An approximate analysis indicates that 1/60 of the sulfur in this outflowing envelope is in the form of H2S, a fraction which may be similar to that in the atmosphere of the central star. In addition, the shape of the observed line profile is discussed in terms of a possible variation of the outflow velocity with latitude above the system's equatorial plane.

  5. Constant envelope chirped OFDM power efficiency

    NASA Astrophysics Data System (ADS)

    Dida, Mussa A.; Hao, Huan; Anjum, M. R.; Ran, Tao

    2016-10-01

    Fractional Fourier OFDM or simply chirped OFDM performs better in time-frequency selective channel than its convectional OFDM. Although chirped OFDM outperforms OFDM it still inherits Peak to Average Power Ratio (PAPR) drawback as a convectional OFDM. To eliminate PAPR drawback Constant Envelope OFDM was developed and for better performance in time frequency selective channel Constant Envelope Fractional Fourier OFDM (CE-COFDM) is used. Its BER performance is analyzed and compared to chirped OFDM and OFDM in AWGN and Rayleigh channel. The simulations show the BER performance of CE-COFDM is the same as chirped OFDM and OFDM. The power efficiency of CE-COFDM is also studied and different simulations performed shows CE-COFDM is more power efficient than chirped OFDM and convectional OFDM for class A and class B Linear Power Amplifier (LPA).

  6. Small carbon chains in circumstellar envelopes

    NASA Astrophysics Data System (ADS)

    Hargreaves, R. J.; Hinkle, K.; Bernath, P. F.

    2014-11-01

    Observations of carbon-rich circumstellar envelopes were made using the Phoenix spectrograph on the Gemini South telescope to determine the abundance of small carbon chain molecules. Vibration-rotation lines of the ν3 antisymmetric stretch of C3 near 2040 cm-1 (4.902 μm) have been used to determine the column density for four carbon-rich circumstellar envelopes: CRL 865, CRL 1922, CRL 2023 and IRC +10216. We additionally calculate the column density of C5 for IRC +10216, and provide an upper limit for five more objects. An upper limit estimate for the C7 column density is also provided for IRC+10216. A comparison of these column densities suggests a revision to current circumstellar chemical models may be needed.

  7. Envelope instability and the fourth order resonance

    NASA Astrophysics Data System (ADS)

    Li, Chao; Zhao, Ya Liang

    2014-12-01

    The well-known envelope instability or the second order even collective mode [I. Hofmann, Phys. Rev. E 57, 4 (1998)] and the fourth order resonance 4 σ =360 ° due to the nonlinear space charge effect in high intensity beams have been studied previously. A wide stop band around 15° is found in a pure periodic focusing channel. In addition, it is illustrated that the fourth order resonance dominates over the envelope instability and practically replaces it in the stop band [D. Jeon et al., Phys. Rev. ST Accel. Beams 12, 054204 (2009)]. In this paper, for a continuous beam with remarkable space charge, our 2D self-consistent particle-in-cell simulation work with the code topopic shows these two kinds of effects respectively in a periodic focusing defocusing (FD) channel. For a fixed tune depression η =0.8 , a stop band with a width of almost 15° is also demonstrated. Moreover, it is confirmed that analytical results of the rms envelope instability diagram are a valid tool to interpret the width of the stop band. Emittance growth rates in stop band are also well explained. It is found that, for a nearly rms matched beam, the emittance growth in the stop band is almost proportional to the saturation time of the nonlinear instability of the envelope, which happens in a quick manner and takes only a few FD cells. In contrast, the fourth order resonance is independent of rms matching and will be accompanied by beam evolution as "a long term effect" once the related mechanism is excited.

  8. The cell envelope glycoconjugates of Mycobacterium tuberculosis

    PubMed Central

    Angala, Shiva Kumar; Belardinelli, Juan Manuel; Huc-Claustre, Emilie; Wheat, William H.; Jackson, Mary

    2015-01-01

    Tuberculosis (TB) remains the second most common cause of death due to a single infectious agent. The cell envelope of Mycobacterium tuberculosis (Mtb), the causative agent of the disease in humans, is a source of unique glycoconjugates and the most distinctive feature of the biology of this organism. It is the basis of much of Mtb pathogenesis and one of the major causes of its intrinsic resistance to chemotherapeutic agents. At the same time, the unique structures of Mtb cell envelope glycoconjugates, their antigenicity and essentiality for mycobacterial growth provide opportunities for drug, vaccine, diagnostic and biomarker development, as clearly illustrated by recent advances in all of these translational aspects. This review focuses on our current understanding of the structure and biogenesis of Mtb glycoconjugates with particular emphasis on one of most intriguing and least understood aspect of the physiology of mycobacteria: the translocation of these complex macromolecules across the different layers of the cell envelope. It further reviews the rather impressive progress made in the last ten years in the discovery and development of novel inhibitors targeting their biogenesis. PMID:24915502

  9. Multiscale envelope manifold for enhanced fault diagnosis of rotating machines

    NASA Astrophysics Data System (ADS)

    Wang, Jun; He, Qingbo; Kong, Fanrang

    2015-02-01

    The wavelet transform has been widely used in the field of machinery fault diagnosis for its good property of band-pass filtering. However, the filtered signal still faces the contamination of in-band noise. This paper focuses on wavelet enveloping, and proposes a new method, called multiscale envelope manifold (MEM), to extract the envelope information of fault impacts with in-band noise suppression. The MEM addresses manifold learning on the wavelet envelopes at multiple scales. Specifically, the proposed method is conducted by three following steps. First, the continuous wavelet transform (CWT) with complex Morlet wavelet base is introduced to obtain the wavelet envelopes at all scales. Second, the wavelet envelopes are restricted in one or more narrow scale bands to simply include the envelope information of fault impacts. The scale band is determined through a smoothness index-based (SI-based) selection method by considering the impulsiveness inside the power spectrum. Third, the manifold learning algorithm is conducted on the wavelet envelopes at selected scales to extract the intrinsic envelope manifold of fault-related impulses. The MEM combines the envelope information at multiple scales in a nonlinear approach, and may thus preserve the factual envelope structure of machinery fault. Simulation studies and experimental verifications confirm that the new method is effective for enhanced fault diagnosis of rotating machines.

  10. Envelope surface ultrastructure and specific gravity of artificially fertilized Pacific cod Gadus macrocephalus eggs.

    PubMed

    Bian, X; Zhang, X; Sakurai, Y; Jin, X; Gao, T; Wan, R; Yamamoto, J

    2014-02-01

    The envelope surface ultrastructure and specific gravity of artificially fertilized eggs of the Pacific cod Gadus macrocephalus were examined. The unfertilized, demersal and slightly adhesive eggs of G. macrocephalus were almost spherical and had no oil globules. Wrinkled envelope surface with elaborated hexagonal reticulated patterns and type I micropyle were observed under a scanning electron microscope. The adhesiveness of the eggs was lost at the blastodermal-cap stage after fertilization. The micropylar canal was sealed by secretion of the perivitelline fluid, and the entire surface became rough. Numerous bacilli were deposited at the micropyle and the outer envelope surface at the late germ-ring stage and at the embryo five-eighths around the yolk stage. The micropyle was completely deformed at the embryo seven-eighths around the yolk stage. The specific gravity of the fertilized G. macrocephalus eggs ranged from c. 1·0316 to 1·0454. These values, however, sharply decreased towards the end stages of egg development to produce pelagic larvae. The ultrastructural changes in the micropyle and envelope surface of the G. macrocephalus eggs protected the embryo from microorganism infections and mechanical stress during the long incubation period. The adhesiveness and specific gravity of the eggs influenced their dispersion potential.

  11. Modeling pollutant penetration across building envelopes

    SciTech Connect

    Liu, De-Ling; Nazaroff, William W.

    2001-04-01

    As air infiltrates through unintentional openings in building envelopes, pollutants may interact with adjacent surfaces. Such interactions can alter human exposure to air pollutants of outdoor origin. We present modeling explorations of the proportion of particles and reactive gases (e.g., ozone) that penetrate building envelopes as air enters through cracks and wall cavities. Calculations were performed for idealized rectangular cracks, assuming regular geometry, smooth inner crack surface and steady airflow. Particles of 0.1-1.0 {micro}m diameter are predicted to have the highest penetration efficiency, nearly unity for crack heights of 0.25 mm or larger, assuming a pressure difference of 4 Pa or greater and a flow path length of 3 cm or less. Supermicron and ultrafine particles are significantly removed by means of gravitational settling and Brownian diffusion, respectively. In addition to crack geometry, ozone penetration depends on its reactivity with crack surfaces, as parameterized by the reaction probability. For reaction probabilities less than {approx}10{sup -5}, penetration is complete for cracks heights greater than 1 mm. However, penetration through mm scale cracks is small if the reaction probability is {approx}10{sup -4} or greater. For wall cavities, fiberglass insulation is an efficient particle filter, but particles would penetrate efficiently through uninsulated wall cavities or through insulated cavities with significant airflow bypass. The ozone reaction probability on fiberglass fibers was measured to be 10{sup -7} for fibers previously exposed to high ozone levels and 6 x 10{sup -6} for unexposed fibers. Over this range, ozone penetration through fiberglass insulation would vary from >90% to {approx}10-40%. Thus, under many conditions penetration is high; however, there are realistic circumstances in which building envelopes can provide substantial pollutant removal. Not enough is yet known about the detailed nature of pollutant penetration

  12. Protective tubes for sodium heated water tubes

    DOEpatents

    Essebaggers, Jan

    1979-01-01

    A heat exchanger in which water tubes are heated by liquid sodium which minimizes the results of accidental contact between the water and the sodium caused by failure of one or more of the water tubes. A cylindrical protective tube envelopes each water tube and the sodium flows axially in the annular spaces between the protective tubes and the water tubes.

  13. 10 CFR 1013.24 - Protective order.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Protective order. 1013.24 Section 1013.24 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) PROGRAM FRAUD CIVIL REMEDIES AND PROCEDURES § 1013.24 Protective... simultaneously file specified documents or information enclosed in sealed envelopes to be opened as directed...

  14. 10 CFR 1013.24 - Protective order.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Protective order. 1013.24 Section 1013.24 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) PROGRAM FRAUD CIVIL REMEDIES AND PROCEDURES § 1013.24 Protective... simultaneously file specified documents or information enclosed in sealed envelopes to be opened as directed...

  15. 10 CFR 1013.24 - Protective order.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Protective order. 1013.24 Section 1013.24 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) PROGRAM FRAUD CIVIL REMEDIES AND PROCEDURES § 1013.24 Protective... simultaneously file specified documents or information enclosed in sealed envelopes to be opened as directed...

  16. 10 CFR 1013.24 - Protective order.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Protective order. 1013.24 Section 1013.24 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) PROGRAM FRAUD CIVIL REMEDIES AND PROCEDURES § 1013.24 Protective... simultaneously file specified documents or information enclosed in sealed envelopes to be opened as directed...

  17. 10 CFR 13.24 - Protective order.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Protective order. 13.24 Section 13.24 Energy NUCLEAR REGULATORY COMMISSION PROGRAM FRAUD CIVIL REMEDIES § 13.24 Protective order. (a) A party or a prospective... information enclosed in sealed envelopes to be opened as directed by the ALJ....

  18. The protein translocon of the plastid envelopes.

    PubMed

    Vojta, Aleksandar; Alavi, Marcel; Becker, Thomas; Hörmann, Friederike; Küchler, Michael; Soll, Jürgen; Thomson, Rowena; Schleiff, Enrico

    2004-05-14

    The Toc and Tic translocon facilitate import of preproteins into chloroplasts. In the past, it was speculated that several translocon subunits act specifically for different types of precursor proteins or in different tissues. To generate a comprehensive picture of the expression and tissue-specific localization of the translocon subunits, their transcript levels were analyzed in roots and leaves. Certain Tocs and Tics were found to be tissue-specific. The protein composition of the transloci in the envelope membranes of chloroplasts was analyzed to describe the function and possible stoichiometry. In contrast to Tic subunits, several Toc subunits seem to have a high turnover.

  19. Surface area coefficients for airship envelopes

    NASA Technical Reports Server (NTRS)

    Diehl, W S

    1922-01-01

    In naval architecture, it is customary to determine the wetted surface of a ship by means of some formula which involves the principal dimensions of the design and suitable constants. These formulas of naval architecture may be extended and applied to the calculation of the surface area of airship envelopes by the use of new values of the constants determined for this purpose. Surface area coefficients were calculated from the actual dimensions, surfaces, and volumes of 52 streamline bodies, which form a series covering the entire range of shapes used in the present aeronautical practice.

  20. Low heat-leak cryogenic envelope

    DOEpatents

    DeHaan, James R.

    1976-10-19

    A plurality of cryogenic envelope sections are joined together to form a power transmission line. Each of the sections is comprised of inner and outer tubes having multilayer metalized plastic spirally wrapped within a vacuum chamber formed between the inner and outer tubes. A refrigeration tube traverses the vacuum chamber, but exits one section and enters another through thermal standoffs for reducing heat-leak from the outer tube to the refrigeration tube. The refrigeration tube passes through a spirally wrapped shield within each section's vacuum chamber in a manner so that the refrigeration tube is in close thermal contact with the shield, but is nevertheless slideable with respect thereto.

  1. Fine-Tuning of the Cpx Envelope Stress Response Is Required for Cell Wall Homeostasis in Escherichia coli

    PubMed Central

    Delhaye, Antoine; Collet, Jean-François

    2016-01-01

    ABSTRACT The envelope of Gram-negative bacteria is an essential compartment that constitutes a protective and permeability barrier between the cell and its environment. The envelope also hosts the cell wall, a mesh-like structure made of peptidoglycan (PG) that determines cell shape and provides osmotic protection. Since the PG must grow and divide in a cell-cycle-synchronized manner, its synthesis and remodeling are tightly regulated. Here, we discovered that PG homeostasis is intimately linked to the levels of activation of the Cpx system, an envelope stress response system traditionally viewed as being involved in protein quality control in the envelope. We first show that Cpx is activated when PG integrity is challenged and that this activation provides protection to cells exposed to antibiotics inhibiting PG synthesis. By rerouting the outer membrane lipoprotein NlpE, a known Cpx activator, to a different envelope subcompartment, we managed to manipulate Cpx activation levels. We found that Cpx overactivation leads to aberrant cellular morphologies, to an increased sensitivity to β-lactams, and to dramatic division and growth defects, consistent with a loss of PG homeostasis. Remarkably, these phenotypes were largely abrogated by the deletion of ldtD, a Cpx-induced gene involved in noncanonical PG cross-linkage, suggesting that this transpeptidase is an important link between PG homeostasis and the Cpx system. Altogether our data show that fine-tuning of an envelope quality control system constitutes an important layer of regulation of the highly organized cell wall structure. PMID:26908573

  2. Envelope as Climate Negotiator: Evaluating adaptive building envelope's capacity to moderate indoor climate and energy

    NASA Astrophysics Data System (ADS)

    Erickson, James

    Through manipulation of adaptable opportunities available within a given environment, individuals become active participants in managing personal comfort requirements, by exercising control over their comfort without the assistance of mechanical heating and cooling systems. Similarly, continuous manipulation of a building skin's form, insulation, porosity, and transmissivity qualities exerts control over the energy exchanged between indoor and outdoor environments. This research uses four adaptive response variables in a modified software algorithm to explore an adaptive building skin's potential in reacting to environmental stimuli with the purpose of minimizing energy use without sacrificing occupant comfort. Results illustrate that significant energy savings can be realized with adaptive envelopes over static building envelopes even under extreme summer and winter climate conditions; that the magnitude of these savings are dependent on climate and orientation; and that occupant thermal comfort can be improved consistently over comfort levels achieved by optimized static building envelopes. The resulting adaptive envelope's unique climate-specific behavior could inform designers in creating an intelligent kinetic aesthetic that helps facilitate adaptability and resiliency in architecture.

  3. On-Line Safe Flight Envelope Determination for Impaired Aircraft

    NASA Technical Reports Server (NTRS)

    Lombaerts, Thomas; Schuet, Stefan; Acosta, Diana; Kaneshige, John

    2015-01-01

    The design and simulation of an on-line algorithm which estimates the safe maneuvering envelope of aircraft is discussed in this paper. The trim envelope is estimated using probabilistic methods and efficient high-fidelity model based computations of attainable equilibrium sets. From this trim envelope, a robust reachability analysis provides the maneuverability limitations of the aircraft through an optimal control formulation. Both envelope limits are presented to the flight crew on the primary flight display. In the results section, scenarios are considered where this adaptive algorithm is capable of computing online changes to the maneuvering envelope due to impairment. Furthermore, corresponding updates to display features on the primary flight display are provided to potentially inform the flight crew of safety critical envelope alterations caused by the impairment.

  4. Tissue specificity in the nuclear envelope supports its functional complexity.

    PubMed

    de Las Heras, Jose I; Meinke, Peter; Batrakou, Dzmitry G; Srsen, Vlastimil; Zuleger, Nikolaj; Kerr, Alastair Rw; Schirmer, Eric C

    2013-01-01

    Nuclear envelope links to inherited disease gave the conundrum of how mutations in near-ubiquitous proteins can yield many distinct pathologies, each focused in different tissues. One conundrum-resolving hypothesis is that tissue-specific partner proteins mediate these pathologies. Such partner proteins may have now been identified with recent proteome studies determining nuclear envelope composition in different tissues. These studies revealed that the majority of the total nuclear envelope proteins are tissue restricted in their expression. Moreover, functions have been found for a number these tissue-restricted nuclear envelope proteins that fit with mechanisms proposed to explain how the nuclear envelope could mediate disease, including defects in mechanical stability, cell cycle regulation, signaling, genome organization, gene expression, nucleocytoplasmic transport, and differentiation. The wide range of functions to which these proteins contribute is consistent with not only their involvement in tissue-specific nuclear envelope disease pathologies, but also tissue evolution.

  5. Tissue specificity in the nuclear envelope supports its functional complexity

    PubMed Central

    de las Heras, Jose I; Meinke, Peter; Batrakou, Dzmitry G; Srsen, Vlastimil; Zuleger, Nikolaj; Kerr, Alastair RW; Schirmer, Eric C

    2013-01-01

    Nuclear envelope links to inherited disease gave the conundrum of how mutations in near-ubiquitous proteins can yield many distinct pathologies, each focused in different tissues. One conundrum-resolving hypothesis is that tissue-specific partner proteins mediate these pathologies. Such partner proteins may have now been identified with recent proteome studies determining nuclear envelope composition in different tissues. These studies revealed that the majority of the total nuclear envelope proteins are tissue restricted in their expression. Moreover, functions have been found for a number these tissue-restricted nuclear envelope proteins that fit with mechanisms proposed to explain how the nuclear envelope could mediate disease, including defects in mechanical stability, cell cycle regulation, signaling, genome organization, gene expression, nucleocytoplasmic transport, and differentiation. The wide range of functions to which these proteins contribute is consistent with not only their involvement in tissue-specific nuclear envelope disease pathologies, but also tissue evolution. PMID:24213376

  6. Coat as a Dagger: The Use of Capsid Proteins to Perforate Membranes during Non-Enveloped DNA Viruses Trafficking

    PubMed Central

    Bilkova, Eva; Forstova, Jitka; Abrahamyan, Levon

    2014-01-01

    To get access to the replication site, small non-enveloped DNA viruses have to cross the cell membrane using a limited number of capsid proteins, which also protect the viral genome in the extracellular environment. Most of DNA viruses have to reach the nucleus to replicate. The capsid proteins involved in transmembrane penetration are exposed or released during endosomal trafficking of the virus. Subsequently, the conserved domains of capsid proteins interact with cellular membranes and ensure their efficient permeabilization. This review summarizes our current knowledge concerning the role of capsid proteins of small non-enveloped DNA viruses in intracellular membrane perturbation in the early stages of infection. PMID:25055856

  7. Glycolate transporter of the pea chloroplast envelope

    SciTech Connect

    Howitz, K.T.

    1985-01-01

    The discovery of a glycolate transporter in the pea (Pisum sativum) chloroplast envelope is described. Several novel silicone oil centrifugation methods were developed to resolve the initial rate kinetics of (/sup 14/C)glycolate transport by isolated, intact pea chloroplasts. Chloroplast glycolate transport was found to be carrier mediated. Transport rates saturated with increasing glycolate concentration. N-Ethylmaleimide (NEM) pretreatment of chloroplasts inhibited transport, an inhibition prevented by glycolate. Glycolate distributed across the envelope in a way which equalized stromal and medium glycolic acid concentrations, limiting possible transport mechanisms to facilitated glycolic acid diffusion, proton symport or hydroxyl antiport. The effects of stomal and medium pH's on the K/sub m/ and V/sub max/ fit the predictions of mobile carrier kinetic models of hydroxyl antiport or proton symport (H/sup +/ binds first). The carrier mediated transport was fast enough to be consistent with in vivo rates of photorespiration. The 2-hydroxymonocarboxylates, glycerate, lactate and glyoxylate are competitive inhibitors of chloroplast glycolate uptake. Glyoxylate, D-lactate and D-glycerate cause glycolate counterflow, indicating that they are also substrates of the glycolate carrier. This finding was confirmed for D-glycerate by studies on glycolate effects on (1-/sup 14/C)D-glycerate transport.

  8. Envelope Modes of Beams with Angular Momentum

    SciTech Connect

    Barnard, J J; Losic, B

    2000-08-21

    For a particle beam propagating in an alternating gradient focusing system, envelope equations are often employed to describe the evolution of the beam radii in the two directions transverse to the direction of propagation, and aligned with the principle axes of the alternating gradient system. When the beams have zero net angular momentum and when the alternating gradient focusing is approximated by a continuous focusing system, there are two normal modes to the envelope equations: the 'breathing' mode and a 'quadrupole' mode. In the former, the two radii oscillate in phase, and in the latter the radii oscillate 180 degrees out of phase. In this paper, we extend the analysis to include beams that have a finite angular momentum. We perturb the moment equations of ref. [1], wherein it was assumed that space charge is a distributed in a uniform density ellipse. Two additional modes are obtained. The breathing mode remains, but the quadrupole mode is split into two modes, and a new low frequency mode appears. We calculate the frequencies and eigenmodes of these four modes as a function of tune depression and a dimensionless net angular momentum. These modes can be excited by rotational errors of the quadrupoles in an alternating gradient focusing channel.

  9. Precision envelope detector and linear rectifier circuitry

    DOEpatents

    Davis, Thomas J.

    1980-01-01

    Disclosed is a method and apparatus for the precise linear rectification and envelope detection of oscillatory signals. The signal is applied to a voltage-to-current converter which supplies current to a constant current sink. The connection between the converter and the sink is also applied through a diode and an output load resistor to a ground connection. The connection is also connected to ground through a second diode of opposite polarity from the diode in series with the load resistor. Very small amplitude voltage signals applied to the converter will cause a small change in the output current of the converter, and the difference between the output current and the constant current sink will be applied either directly to ground through the single diode, or across the output load resistor, dependent upon the polarity. Disclosed also is a full-wave rectifier utilizing constant current sinks and voltage-to-current converters. Additionally, disclosed is a combination of the voltage-to-current converters with differential integrated circuit preamplifiers to boost the initial signal amplitude, and with low pass filtering applied so as to obtain a video or signal envelope output.

  10. Functional organization of the HIV lipid envelope

    PubMed Central

    Huarte, Nerea; Carravilla, Pablo; Cruz, Antonio; Lorizate, Maier; Nieto-Garai, Jon A.; Kräusslich, Hans-Georg; Pérez-Gil, Jesús; Requejo-Isidro, Jose; Nieva, José L.

    2016-01-01

    The chemical composition of the human immunodeficiency virus type 1 (HIV-1) membrane is critical for fusion and entry into target cells, suggesting that preservation of a functional lipid bilayer organization may be required for efficient infection. HIV-1 acquires its envelope from the host cell plasma membrane at sites enriched in raft-type lipids. Furthermore, infectious particles display aminophospholipids on their surface, indicative of dissipation of the inter-leaflet lipid asymmetry metabolically generated at cellular membranes. By combining two-photon excited Laurdan fluorescence imaging and atomic force microscopy, we have obtained unprecedented insights into the phase state of membranes reconstituted from viral lipids (i.e., extracted from infectious HIV-1 particles), established the role played by the different specimens in the mixtures, and characterized the effects of membrane-active virucidal agents on membrane organization. In determining the molecular basis underlying lipid packing and lateral heterogeneity of the HIV-1 membrane, our results may help develop compounds with antiviral activity acting by perturbing the functional organization of the lipid envelope. PMID:27678107

  11. TRANSPARENT HELIUM IN STRIPPED ENVELOPE SUPERNOVAE

    SciTech Connect

    Piro, Anthony L.; Morozova, Viktoriya S.

    2014-09-01

    Using simple arguments based on photometric light curves and velocity evolution, we propose that some stripped envelope supernovae (SNe) show signs that a significant fraction of their helium is effectively transparent. The main pieces of evidence are the relatively low velocities with little velocity evolution, as are expected deep inside an exploding star, along with temperatures that are too low to ionize helium. This means that the helium should not contribute to the shaping of the main SN light curve, and thus the total helium mass may be difficult to measure from simple light curve modeling. Conversely, such modeling may be more useful for constraining the mass of the carbon/oxygen core of the SN progenitor. Other stripped envelope SNe show higher velocities and larger velocity gradients, which require an additional opacity source (perhaps the mixing of heavier elements or radioactive nickel) to prevent the helium from being transparent. We discuss ways in which similar analysis can provide insights into the differences and similarities between SNe Ib and Ic, which will lead to a better understanding of their respective formation mechanisms.

  12. Sensitivity to changes in amplitude envelope

    NASA Astrophysics Data System (ADS)

    Gallun, Erick; Hafter, Ervin R.; Bonnel, Anne-Marie

    2002-05-01

    Detection of a brief increment in a tonal pedestal is less well predicted by energy-detection (e.g., Macmillan, 1973; Bonnel and Hafter, 1997) than by sensitivity to changes in the stimulus envelope. As this implies a mechanism similar to an envelope extractor (Viemeister, 1979), sinusoidal amplitude modulation was used to mask a single ramped increment (10, 45, or 70 ms) added to a 1000-ms pedestal with carrier frequency (cf)=477 Hz. As in informational masking (Neff, 1994) and ``modulation-detection interference'' (Yost and Sheft, 1989), interference occurred with masker cfs of 477 and 2013 Hz. While slight masking was found with modulation frequencies (mfs) from 16 to 96 Hz, masking grew inversely with still lower mfs, being greatest for mf=4 Hz. This division is reminiscent of that said to separate sensations of ``roughness'' and ``beats,'' respectively (Terhardt, 1974), with the latter also being related to durations associated with auditory groupings in music and speech. Importantly, this result held for all of the signal durations and onset-offset ramps tested, suggesting that an increment on a pedestal is treated as a single auditory object whose detection is most difficult in the presence of other objects (in this case, ``beats'').

  13. The cell envelope stress response of Bacillus subtilis: from static signaling devices to dynamic regulatory network.

    PubMed

    Radeck, Jara; Fritz, Georg; Mascher, Thorsten

    2017-02-01

    The cell envelope stress response (CESR) encompasses all regulatory events that enable a cell to protect the integrity of its envelope, an essential structure of any bacterial cell. The underlying signaling network is particularly well understood in the Gram-positive model organism Bacillus subtilis. It consists of a number of two-component systems (2CS) and extracytoplasmic function σ factors that together regulate the production of both specific resistance determinants and general mechanisms to protect the envelope against antimicrobial peptides targeting the biogenesis of the cell wall. Here, we summarize the current picture of the B. subtilis CESR network, from the initial identification of the corresponding signaling devices to unraveling their interdependence and the underlying regulatory hierarchy within the network. In the course of detailed mechanistic studies, a number of novel signaling features could be described for the 2CSs involved in mediating CESR. This includes a novel class of so-called intramembrane-sensing histidine kinases (IM-HKs), which-instead of acting as stress sensors themselves-are activated via interprotein signal transfer. Some of these IM-HKs are involved in sensing the flux of antibiotic resistance transporters, a unique mechanism of responding to extracellular antibiotic challenge.

  14. Defining the Core Proteome of the Chloroplast Envelope Membranes

    PubMed Central

    Simm, Stefan; Papasotiriou, Dimitrios G.; Ibrahim, Mohamed; Leisegang, Matthias S.; Müller, Bernd; Schorge, Tobias; Karas, Michael; Mirus, Oliver; Sommer, Maik S.; Schleiff, Enrico

    2013-01-01

    High-throughput protein localization studies require multiple strategies. Mass spectrometric analysis of defined cellular fractions is one of the complementary approaches to a diverse array of cell biological methods. In recent years, the protein content of different cellular (sub-)compartments was approached. Despite of all the efforts made, the analysis of membrane fractions remains difficult, in that the dissection of the proteomes of the envelope membranes of chloroplasts or mitochondria is often not reliable because sample purity is not always warranted. Moreover, proteomic studies are often restricted to single (model) species, and therefore limited in respect to differential individual evolution. In this study we analyzed the chloroplast envelope proteomes of different plant species, namely, the individual proteomes of inner and outer envelope (OE) membrane of Pisum sativum and the mixed envelope proteomes of Arabidopsis thaliana and Medicago sativa. The analysis of all three species yielded 341 identified proteins in total, 247 of them being unique. 39 proteins were genuine envelope proteins found in at least two species. Based on this and previous envelope studies we defined the core envelope proteome of chloroplasts. Comparing the general overlap of the available six independent studies (including ours) revealed only a number of 27 envelope proteins. Depending on the stringency of applied selection criteria we found 231 envelope proteins, while less stringent criteria increases this number to 649 putative envelope proteins. Based on the latter we provide a map of the outer and inner envelope core proteome, which includes many yet uncharacterized proteins predicted to be involved in transport, signaling, and response. Furthermore, a foundation for the functional characterization of yet unidentified functions of the inner and OE for further analyses is provided. PMID:23390424

  15. LINCing complex functions at the nuclear envelope

    PubMed Central

    Rothballer, Andrea; Schwartz, Thomas U.; Kutay, Ulrike

    2013-01-01

    Linker of nucleoskeleton and cytoskeleton (LINC) complexes span the double membrane of the nuclear envelope (NE) and physically connect nuclear structures to cytoskeletal elements. LINC complexes are envisioned as force transducers in the NE, which facilitate processes like nuclear anchorage and migration, or chromosome movements. The complexes are built from members of two evolutionary conserved families of transmembrane (TM) proteins, the SUN (Sad1/UNC-84) domain proteins in the inner nuclear membrane (INM) and the KASH (Klarsicht/ANC-1/SYNE homology) domain proteins in the outer nuclear membrane (ONM). In the lumen of the NE, the SUN and KASH domains engage in an intimate assembly to jointly form a NE bridge. Detailed insights into the molecular architecture and atomic structure of LINC complexes have recently revealed the molecular basis of nucleo-cytoskeletal coupling. They bear important implications for LINC complex function and suggest new potential and as yet unexplored roles, which the complexes may play in the cell. PMID:23324460

  16. Fullerenes and fulleranes in circumstellar envelopes

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Kwok, Sun; Sadjadi, SeyedAbdolreza

    2016-07-01

    Three decades of search have recently led to convincing discoveries of cosmic fullerenes. The presence of C60 and C+ 60 in both circumstellar and interstellar environments suggests that these molecules and their derivatives can be efficiently formed in circumstellar envelopes and survive in harsh conditions. Detailed analysis of the infrared bands from fullerenes and their connections with the local properties can provide valuable information on the physical conditions and chemical processes that occurred in the late stages of stellar evolution. The identification of C+ 60 as the carrier of four diffuse interstellar bands (DIBs) suggests that fullerene- related compounds are abundant in interstellar space and are essential for resolving the DIB mystery. Experiments have revealed a high hydrogenation rate when C60 is exposed to atomic hydrogen, motivating the attempt to search for cosmic fulleranes. In this paper, we present a short review of current knowledge of cosmic fullerenes and fulleranes and briefly discuss the implications on circumstellar chemistry.

  17. ASYMMETRIC ACCRETION FLOWS WITHIN A COMMON ENVELOPE

    SciTech Connect

    MacLeod, Morgan; Ramirez-Ruiz, Enrico

    2015-04-10

    This paper examines flows in the immediate vicinity of stars and compact objects dynamically inspiralling within a common envelope (CE). Flow in the vicinity of the embedded object is gravitationally focused, leading to drag and potentially to gas accretion. This process has been studied numerically and analytically in the context of Hoyle–Lyttleton accretion (HLA). Yet, within a CE, accretion structures may span a large fraction of the envelope radius, and in so doing sweep across a substantial radial gradient of density. We quantify these gradients using detailed stellar evolution models for a range of CE encounters. We provide estimates of typical scales in CE encounters that involve main sequence stars, white dwarfs, neutron stars, and black holes with giant-branch companions of a wide range of masses. We apply these typical scales to hydrodynamic simulations of three-dimensional HLA with an upstream density gradient. This density gradient breaks the symmetry that defines HLA flow, and imposes an angular momentum barrier to accretion. Material that is focused into the vicinity of the embedded object thus may not be able to accrete. As a result, accretion rates drop dramatically, by one to two orders of magnitude, while drag rates are only mildly affected. We provide fitting formulae to the numerically derived rates of drag and accretion as a function of the density gradient. The reduced ratio of accretion to drag suggests that objects that can efficiently gain mass during CE evolution, such as black holes and neutron stars, may grow less than implied by the HLA formalism.

  18. Enhanced conformational sampling using enveloping distribution sampling.

    PubMed

    Lin, Zhixiong; van Gunsteren, Wilfred F

    2013-10-14

    To lessen the problem of insufficient conformational sampling in biomolecular simulations is still a major challenge in computational biochemistry. In this article, an application of the method of enveloping distribution sampling (EDS) is proposed that addresses this challenge and its sampling efficiency is demonstrated in simulations of a hexa-β-peptide whose conformational equilibrium encompasses two different helical folds, i.e., a right-handed 2.7(10∕12)-helix and a left-handed 3(14)-helix, separated by a high energy barrier. Standard MD simulations of this peptide using the GROMOS 53A6 force field did not reach convergence of the free enthalpy difference between the two helices even after 500 ns of simulation time. The use of soft-core non-bonded interactions in the centre of the peptide did enhance the number of transitions between the helices, but at the same time led to neglect of relevant helical configurations. In the simulations of a two-state EDS reference Hamiltonian that envelops both the physical peptide and the soft-core peptide, sampling of the conformational space of the physical peptide ensures that physically relevant conformations can be visited, and sampling of the conformational space of the soft-core peptide helps to enhance the transitions between the two helices. The EDS simulations sampled many more transitions between the two helices and showed much faster convergence of the relative free enthalpy of the two helices compared with the standard MD simulations with only a slightly larger computational effort to determine optimized EDS parameters. Combined with various methods to smoothen the potential energy surface, the proposed EDS application will be a powerful technique to enhance the sampling efficiency in biomolecular simulations.

  19. Comparative proteomic analyses of the nuclear envelope and pore complex suggests a wide range of heretofore unexpected functions.

    PubMed

    Batrakou, Dzmitry G; Kerr, Alastair R W; Schirmer, Eric C

    2009-02-15

    Since the discovery of several inherited diseases linked to the nuclear envelope the number of functions ascribed to this subcellular organelle has skyrocketed. However the molecular pathways underlying these functions are not clear in most cases, perhaps because of missing components. Several recent proteomic analyses of the nuclear envelope and nuclear pore complex proteomes have yielded not only enough missing components to potentially elucidate these pathways, but suggest an exponentially greater number of functions at the nuclear periphery than ever imagined. Many of these functions appear to derive from recapitulation of pathways utilized at the plasma membrane and from other membrane systems. Additionally, many proteins identified in the comparative nuclear envelope studies have sequence characteristics suggesting that they might also contribute to nuclear pore complex functions. In particular, the striking enrichment for proteins in the nuclear envelope fractions that carry phenylalanine-glycine (FG) repeats may be significant for the mechanism of nuclear transport. In retrospect, these findings are only surprising in context of the notion held for many years that the nuclear envelope was only a barrier protecting the genome. In fact, it is arguably the most complex membrane organelle in the cell.

  20. Modeling Protostar Envelopes and Disks Seen With ALMA

    NASA Astrophysics Data System (ADS)

    Terebey, Susan; Flores-Rivera, Lizxandra; Willacy, Karen

    2017-01-01

    Thermal continuum emission from protostars comes from both the envelope and circumstellar disk. The dust emits on a variety of spatial scales, ranging from sub-arcseconds for disks to roughly 10 arcseconds for envelopes for nearby protostars. We present models of what ALMA should detect that incorporate a self-consistent collapse solution, radiative transfer, and realistic dust properties.

  1. Computer-Based Instruction on Skills for Addressing Envelopes.

    ERIC Educational Resources Information Center

    Humes, Ann

    The approach to computer-based instruction for third and fourth grade elementary students which is sketched teaches component placement, capitalization, and punctuation skills of addressing envelopes within the context of a simulated envelope. Part of a larger design for a complete program of composition instruction, this program comprises a set…

  2. Data Envelopment Analysis: Measurement of Educational Efficiency in Texas

    ERIC Educational Resources Information Center

    Carter, Lacy

    2012-01-01

    The purpose of this study was to examine the efficiency of Texas public school districts through Data Envelopment Analysis. The Data Envelopment Analysis estimation method calculated and assigned efficiency scores to each of the 931 school districts considered in the study. The efficiency scores were utilized in two phases. First, the school…

  3. 10 CFR 434.516 - Building exterior envelope.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Building exterior envelope. 434.516 Section 434.516 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CODE FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH RISE RESIDENTIAL BUILDINGS Building Energy Cost Compliance Alternative § 434.516 Building exterior envelope....

  4. Rolling bearing feature frequency extraction using extreme average envelope decomposition

    NASA Astrophysics Data System (ADS)

    Shi, Kunju; Liu, Shulin; Jiang, Chao; Zhang, Hongli

    2016-09-01

    The vibration signal contains a wealth of sensitive information which reflects the running status of the equipment. It is one of the most important steps for precise diagnosis to decompose the signal and extracts the effective information properly. The traditional classical adaptive signal decomposition method, such as EMD, exists the problems of mode mixing, low decomposition accuracy etc. Aiming at those problems, EAED(extreme average envelope decomposition) method is presented based on EMD. EAED method has three advantages. Firstly, it is completed through midpoint envelopment method rather than using maximum and minimum envelopment respectively as used in EMD. Therefore, the average variability of the signal can be described accurately. Secondly, in order to reduce the envelope errors during the signal decomposition, replacing two envelopes with one envelope strategy is presented. Thirdly, the similar triangle principle is utilized to calculate the time of extreme average points accurately. Thus, the influence of sampling frequency on the calculation results can be significantly reduced. Experimental results show that EAED could separate out single frequency components from a complex signal gradually. EAED could not only isolate three kinds of typical bearing fault characteristic of vibration frequency components but also has fewer decomposition layers. EAED replaces quadratic enveloping to an envelope which ensuring to isolate the fault characteristic frequency under the condition of less decomposition layers. Therefore, the precision of signal decomposition is improved.

  5. Planet formation with envelope enrichment: new insights on planetary diversity

    NASA Astrophysics Data System (ADS)

    Venturini, Julia; Alibert, Yann; Benz, Willy

    2016-12-01

    Aims: We compute for the first time self-consistent models of planet growth that include the effect of envelope enrichment. The change in envelope metallicity is assumed to be the result of planetesimal disruption or icy pebble sublimation. Methods: We solved internal structure equations taking into account global energy conservation for the envelope to compute in situ planetary growth. We considered different opacities and equations of state suited for a wide range of metallicities. Results: We find that envelope enrichment speeds up the formation of gas giants. It also explains naturally the formation of low- and intermediate-mass objects with large fractions of H-He ( 20-30% in mass). High-opacity models explain the metallicity of the giant planets of the solar system well, while low-opacity models are suited to explain the formation of low-mass objects with thick H-He envelopes and gas giants with sub-solar envelope metallicities. We find good agreement between our models and the estimated water abundance for WASP-43b. For HD 189733b, HD 209458b, and WASP-12b we predict fractions of water higher than what is estimated from observations by at least a factor 2. Conclusions: Envelope enrichment by icy planetesimals is the natural scenario to explain the formation of a wide variety of objects, ranging from mini-Neptunes to gas giants. We predict that the total and envelope metallicity decrease with planetary mass.

  6. 14 CFR 29.87 - Height-velocity envelope.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Height-velocity envelope. 29.87 Section 29... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.87 Height-velocity envelope. (a) If there is any combination of height and forward velocity (including hover) under which a...

  7. 14 CFR 29.87 - Height-velocity envelope.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Height-velocity envelope. 29.87 Section 29... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.87 Height-velocity envelope. (a) If there is any combination of height and forward velocity (including hover) under which a...

  8. 14 CFR 29.87 - Height-velocity envelope.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Height-velocity envelope. 29.87 Section 29... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.87 Height-velocity envelope. (a) If there is any combination of height and forward velocity (including hover) under which a...

  9. 14 CFR 29.87 - Height-velocity envelope.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Height-velocity envelope. 29.87 Section 29... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.87 Height-velocity envelope. (a) If there is any combination of height and forward velocity (including hover) under which a...

  10. 14 CFR 29.87 - Height-velocity envelope.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Height-velocity envelope. 29.87 Section 29... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.87 Height-velocity envelope. (a) If there is any combination of height and forward velocity (including hover) under which a...

  11. An Inside Look at the Two Envelopes Paradox

    ERIC Educational Resources Information Center

    Falk, Ruma; Nickerson, Raymond S.

    2009-01-01

    When two sealed envelopes contain money, one twice as much as the other, a player should be indifferent between them. But when one envelope is opened, one's decision should vary as a function of the observed value and one's subjective probabilities.

  12. A Spectral Algorithm for Envelope Reduction of Sparse Matrices

    NASA Technical Reports Server (NTRS)

    Barnard, Stephen T.; Pothen, Alex; Simon, Horst D.

    1993-01-01

    The problem of reordering a sparse symmetric matrix to reduce its envelope size is considered. A new spectral algorithm for computing an envelope-reducing reordering is obtained by associating a Laplacian matrix with the given matrix and then sorting the components of a specified eigenvector of the Laplacian. This Laplacian eigenvector solves a continuous relaxation of a discrete problem related to envelope minimization called the minimum 2-sum problem. The permutation vector computed by the spectral algorithm is a closest permutation vector to the specified Laplacian eigenvector. Numerical results show that the new reordering algorithm usually computes smaller envelope sizes than those obtained from the current standard algorithms such as Gibbs-Poole-Stockmeyer (GPS) or SPARSPAK reverse Cuthill-McKee (RCM), in some cases reducing the envelope by more than a factor of two.

  13. Envelope Enhancement Increases Cortical Sensitivity to Interaural Envelope Delays with Acoustic and Electric Hearing

    PubMed Central

    Hartley, Douglas E. H.; Isaiah, Amal

    2014-01-01

    Evidence from human psychophysical and animal electrophysiological studies suggests that sensitivity to interaural time delay (ITD) in the modulating envelope of a high-frequency carrier can be enhanced using half-wave rectified stimuli. Recent evidence has shown potential benefits of equivalent electrical stimuli to deaf individuals with bilateral cochlear implants (CIs). In the current study we assessed the effects of envelope shape on ITD sensitivity in the primary auditory cortex of normal-hearing ferrets, and profoundly-deaf animals with bilateral CIs. In normal-hearing animals, cortical sensitivity to ITDs (±1 ms in 0.1-ms steps) was assessed in response to dichotically-presented i) sinusoidal amplitude-modulated (SAM) and ii) half-wave rectified (HWR) tones (100-ms duration; 70 dB SPL) presented at the best-frequency of the unit over a range of modulation frequencies. In separate experiments, adult ferrets were deafened with neomycin administration and bilaterally-implanted with intra-cochlear electrode arrays. Electrically-evoked auditory brainstem responses (EABRs) were recorded in response to bipolar electrical stimulation of the apical pair of electrodes with singe biphasic current pulses (40 µs per phase) over a range of current levels to measure hearing thresholds. Subsequently, we recorded cortical sensitivity to ITDs (±800 µs in 80-µs steps) within the envelope of SAM and HWR biphasic-pulse trains (40 µs per phase; 6000 pulses per second, 100-ms duration) over a range of modulation frequencies. In normal-hearing animals, nearly a third of cortical neurons were sensitive to envelope-ITDs in response to SAM tones. In deaf animals with bilateral CI, the proportion of ITD-sensitive cortical neurons was approximately a fifth in response to SAM pulse trains. In normal-hearing and deaf animals with bilateral CI the proportion of ITD sensitive units and neural sensitivity to ITDs increased in response to HWR, compared with SAM stimuli. Consequently

  14. Release of outer membrane vesicles by Gram-negative bacteria is a novel envelope stress response

    PubMed Central

    McBroom, Amanda J; Kuehn, Meta J

    2007-01-01

    Conditions that impair protein folding in the Gram-negative bacterial envelope cause stress. The destabilizing effects of stress in this compartment are recognized and countered by a number of signal transduction mechanisms. Data presented here reveal another facet of the complex bacterial stress response, release of outer membrane vesicles. Native vesicles are composed of outer membrane and periplasmic material, and they are released from the bacterial surface without loss of membrane integrity. Here we demonstrate that the quantity of vesicle release correlates directly with the level of protein accumulation in the cell envelope. Accumulation of material occurs under stress, and is exacerbated upon impairment of the normal housekeeping and stress-responsive mechanisms of the cell. Mutations that cause increased vesiculation enhance bacterial survival upon challenge with stressing agents or accumulation of toxic misfolded proteins. Preferential packaging of a misfolded protein mimic into vesicles for removal indicates that the vesiculation process can act to selectively eliminate unwanted material. Our results demonstrate that production of bacterial outer membrane vesicles is a fully independent, general envelope stress response. In addition to identifying a novel mechanism for alleviating stress, this work provides physiological relevance for vesicle production as a protective mechanism. PMID:17163978

  15. Reviewed approach to defining the Active Interlock Envelope for Front End ray tracing

    SciTech Connect

    Seletskiy, S.; Shaftan, T.

    2015-09-24

    To protect the NSLS-II Storage Ring (SR) components from damage from synchrotron radiation produced by insertion devices (IDs) the Active Interlock (AI) keeps electron beam within some safe envelope (a.k.a Active Interlock Envelope or AIE) in the transverse phase space. The beamline Front Ends (FEs) are designed under assumption that above certain beam current (typically 2 mA) the ID synchrotron radiation (IDSR) fan is produced by the interlocked e-beam. These assumptions also define how the ray tracing for FE is done. To simplify the FE ray tracing for typical uncanted ID it was decided to provide the Mechanical Engineering group with a single set of numbers (x,x’,y,y’) for the AIE at the center of the long (or short) ID straight section. Such unified approach to the design of the beamline Front Ends will accelerate the design process and save valuable human resources. In this paper we describe our new approach to defining the AI envelope and provide the resulting numbers required for design of the typical Front End.

  16. Neural coding of echo-envelope disparities in echolocating bats.

    PubMed

    Borina, Frank; Firzlaff, Uwe; Wiegrebe, Lutz

    2011-05-01

    The effective use of echolocation requires not only measuring the delay between the emitted call and returning echo to estimate the distance of an ensonified object. To locate an object in azimuth and elevation, the bat's auditory system must analyze the returning echoes in terms of their binaural properties, i.e., the echoes' interaural intensity and time differences (IIDs and ITDs). The effectiveness of IIDs for echolocation is undisputed, but when bats ensonify complex objects, the temporal structure of echoes may facilitate the analysis of the echo envelope in terms of envelope ITDs. Using extracellular recordings from the auditory midbrain of the bat, Phyllostomus discolor, we found a population of neurons that are sensitive to envelope ITDs of echoes of their sonar calls. Moreover, the envelope-ITD sensitivity improved with increasing temporal fluctuations in the echo envelopes, a sonar parameter related to the spatial statistics of complex natural reflectors like vegetation. The data show that in bats envelope ITDs may be used not only to locate external, prey-generated rustling sounds but also in the context of echolocation. Specifically, the temporal fluctuations in the echo envelope, which are created when the sonar emission is reflected from a complex natural target, support ITD-mediated echolocation.

  17. Vitelline envelope, chorion, and micropyle of Fundulus heteroclitus eggs

    SciTech Connect

    Dumont, J.N.; Brummet, A.R.

    1980-01-01

    The architecture and transformation of the vitelline envelope of the developing oocyte into the chorion of the mature egg of Fundulus heteroclitus have been examined by scanning and transmission electron microscopy. The mature vitelline envelope is structurally complex and consists of about nine strata. The envelope is penetrated by pore canals that contain microvilli arising from the oocyte and macrovilli from follicle cells. During the envelope's transformation into the chorion, the pore canals are lost and the envelope becomes more fibrous and compact and its stratified nature less apparent. The micropyle, or pore, through which the sperm gains access to the enclosed egg is located at the bottom of a small funnel-shaped depression in the envelope. Internally, the micropyle opens on the apex of a cone-like elevation of the chorion. During the development of the envelope, structured chorionic fibrils, the components of which are presumed to be synthesized by the follicle cells, become attached to its surface. These chorionic fibrils are thought to aid in the attachment of the egg to the substratum and perhaps to help prevent water loss during low tides when the egg may be exposed.

  18. CLOSE STELLAR BINARY SYSTEMS BY GRAZING ENVELOPE EVOLUTION

    SciTech Connect

    Soker, Noam

    2015-02-20

    I suggest a spiral-in process in which a stellar companion grazes the envelope of a giant star while both the orbital separation and the giant radius shrink simultaneously, forming a close binary system. The binary system might be viewed as evolving in a constant state of 'just entering a common envelope (CE) phase.' In cases where this process takes place, it can be an alternative to CE evolution where the secondary star is immersed in the giant's envelope. Grazing envelope evolution (GEE) is made possible only if the companion manages to accrete mass at a high rate and launches jets that remove the outskirts of the giant envelope, hence preventing the formation of a CE. The high accretion rate is made possible by the accretion disk launching jets which efficiently carry the excess angular momentum and energy from the accreted mass. The orbital decay itself is caused by the gravitational interaction of the secondary star with the envelope inward of its orbit, i.e., dynamical friction (gravitational tide). Mass loss through the second Lagrangian point can carry additional angular momentum and envelope mass. The GEE lasts for tens to hundreds of years. The high accretion rate, with peaks lasting from months to years, might lead to a bright object referred to as the intermediate luminosity optical transient (Red Novae; Red Transients). A bipolar nebula and/or equatorial ring are formed around the binary remnant.

  19. Hymenolepis nana: the fine structure of the embryonic envelopes.

    PubMed

    Fairweather, I; Threadgold, L T

    1981-06-01

    The fine structure of the envelopes surrounding hatched and unhatched oncospheres of Hymenolepis nana has been investigated by transmission and scanning electron microscopy (SEM), together with light microscope histochemical observations of JB-4 embedded material. The oncosphere is surrounded by 3 layers--the capsule, the outer envelope and the inner envelope, the latter giving rise to the embryophore and the 'oncospheral membrane'. An additional layer--the polar filament layer--lies between the 'oncospheral membrane' and the oncosphere. Shell material is deposited on the capsule as a thin layer. It is secreted by the outer envelope, which degenerates once shell formation is complete. The uterus may also contribute to shell formation. The embryophore forms a thin incomplete and peripheral layer within the inner envelope. In the basal region of this envelope, partial development of an 'oncospheral membrane' takes place, but it does not become detached as a separate layer. The polar filaments, which are characteristic of the oncosphere of H. nana, are derived from the epithelial covering of the oncosphere itself, which delaminates to form a separate polar filament layer. The filaments arise from knob-like projections at opposite poles of this layer. The design of the embryonic envelopes in H. nana show a number of modifications from the basic cyclophyllidean pattern, and these can be related to the demands of its 'direct' life-cycle.

  20. Real-Time Flight Envelope Monitoring System

    NASA Technical Reports Server (NTRS)

    Kerho, Michael; Bragg, Michael B.; Ansell, Phillip J.

    2012-01-01

    The objective of this effort was to show that real-time aircraft control-surface hinge-moment information could be used to provide a robust and reliable prediction of vehicle performance and control authority degradation. For a given airfoil section with a control surface -- be it a wing with an aileron, rudder, or elevator -- the control-surface hinge moment is sensitive to the aerodynamic characteristics of the section. As a result, changes in the aerodynamics of the section due to angle-of-attack or environmental effects such as icing, heavy rain, surface contaminants, bird strikes, or battle damage will affect the control surface hinge moment. These changes include both the magnitude of the hinge moment and its sign in a time-averaged sense, and the variation of the hinge moment with time. The current program attempts to take the real-time hinge moment information from the aircraft control surfaces and develop a system to predict aircraft envelope boundaries across a range of conditions, alerting the flight crew to reductions in aircraft controllability and flight boundaries.

  1. Critical point analysis of phase envelope diagram

    NASA Astrophysics Data System (ADS)

    Soetikno, Darmadi; Kusdiantara, Rudy; Puspita, Dila; Sidarto, Kuntjoro A.; Siagian, Ucok W. R.; Soewono, Edy; Gunawan, Agus Y.

    2014-03-01

    Phase diagram or phase envelope is a relation between temperature and pressure that shows the condition of equilibria between the different phases of chemical compounds, mixture of compounds, and solutions. Phase diagram is an important issue in chemical thermodynamics and hydrocarbon reservoir. It is very useful for process simulation, hydrocarbon reactor design, and petroleum engineering studies. It is constructed from the bubble line, dew line, and critical point. Bubble line and dew line are composed of bubble points and dew points, respectively. Bubble point is the first point at which the gas is formed when a liquid is heated. Meanwhile, dew point is the first point where the liquid is formed when the gas is cooled. Critical point is the point where all of the properties of gases and liquids are equal, such as temperature, pressure, amount of substance, and others. Critical point is very useful in fuel processing and dissolution of certain chemicals. Here in this paper, we will show the critical point analytically. Then, it will be compared with numerical calculations of Peng-Robinson equation by using Newton-Raphson method. As case studies, several hydrocarbon mixtures are simulated using by Matlab.

  2. Aeroelastic Model Structure Computation for Envelope Expansion

    NASA Technical Reports Server (NTRS)

    Kukreja, Sunil L.

    2007-01-01

    Structure detection is a procedure for selecting a subset of candidate terms, from a full model description, that best describes the observed output. This is a necessary procedure to compute an efficient system description which may afford greater insight into the functionality of the system or a simpler controller design. Structure computation as a tool for black-box modeling may be of critical importance in the development of robust, parsimonious models for the flight-test community. Moreover, this approach may lead to efficient strategies for rapid envelope expansion that may save significant development time and costs. In this study, a least absolute shrinkage and selection operator (LASSO) technique is investigated for computing efficient model descriptions of non-linear aeroelastic systems. The LASSO minimises the residual sum of squares with the addition of an l(Sub 1) penalty term on the parameter vector of the traditional l(sub 2) minimisation problem. Its use for structure detection is a natural extension of this constrained minimisation approach to pseudo-linear regression problems which produces some model parameters that are exactly zero and, therefore, yields a parsimonious system description. Applicability of this technique for model structure computation for the F/A-18 (McDonnell Douglas, now The Boeing Company, Chicago, Illinois) Active Aeroelastic Wing project using flight test data is shown for several flight conditions (Mach numbers) by identifying a parsimonious system description with a high percent fit for cross-validated data.

  3. Discriminating Dysarthria Type From Envelope Modulation Spectra

    PubMed Central

    Liss, Julie M.; LeGendre, Sue; Lotto, Andrew J.

    2013-01-01

    Purpose Previous research demonstrated the ability of temporally based rhythm metrics to distinguish among dysarthrias with different prosodic deficit profiles (J. M. Liss et al., 2009). The authors examined whether comparable results could be obtained by an automated analysis of speech envelope modulation spectra (EMS), which quantifies the rhythmicity of speech within specified frequency bands. Method EMS was conducted on sentences produced by 43 speakers with 1 of 4 types of dysarthria and healthy controls. The EMS consisted of the spectra of the slow-rate (up to 10 Hz) amplitude modulations of the full signal and 7 octave bands ranging in center frequency from 125 to 8000 Hz. Six variables were calculated for each band relating to peak frequency and amplitude and relative energy above, below, and in the region of 4 Hz. Discriminant function analyses (DFA) determined which sets of predictor variables best discriminated between and among groups. Results Each of 6 DFAs identified 2–6 of the 48 predictor variables. These variables achieved 84%–100% classification accuracy for group membership. Conclusions Dysarthrias can be characterized by quantifiable temporal patterns in acoustic output. Because EMS analysis is automated and requires no editing or linguistic assumptions, it shows promise as a clinical and research tool. PMID:20643800

  4. Critical point analysis of phase envelope diagram

    SciTech Connect

    Soetikno, Darmadi; Siagian, Ucok W. R.; Kusdiantara, Rudy Puspita, Dila Sidarto, Kuntjoro A. Soewono, Edy; Gunawan, Agus Y.

    2014-03-24

    Phase diagram or phase envelope is a relation between temperature and pressure that shows the condition of equilibria between the different phases of chemical compounds, mixture of compounds, and solutions. Phase diagram is an important issue in chemical thermodynamics and hydrocarbon reservoir. It is very useful for process simulation, hydrocarbon reactor design, and petroleum engineering studies. It is constructed from the bubble line, dew line, and critical point. Bubble line and dew line are composed of bubble points and dew points, respectively. Bubble point is the first point at which the gas is formed when a liquid is heated. Meanwhile, dew point is the first point where the liquid is formed when the gas is cooled. Critical point is the point where all of the properties of gases and liquids are equal, such as temperature, pressure, amount of substance, and others. Critical point is very useful in fuel processing and dissolution of certain chemicals. Here in this paper, we will show the critical point analytically. Then, it will be compared with numerical calculations of Peng-Robinson equation by using Newton-Raphson method. As case studies, several hydrocarbon mixtures are simulated using by Matlab.

  5. Localization of phosphatidylcholine in outer envelope membrane of spinach chloroplasts

    PubMed Central

    1985-01-01

    We have examined the effects of phospholipase C from Bacillus cereus on the extent of phospholipid hydrolysis in envelope membrane vesicles and in intact chloroplasts. When isolated envelope vesicles were incubated in presence of phospholipase C, phosphatidylcholine and phosphatidylglycerol, but not phosphatidylinositol, were totally converted into diacylglycerol if they were available to the enzyme (i.e., when the vesicles were sonicated in presence of phospholipase C). These experiments demonstrate that phospholipase C can be used to probe the availability of phosphatidylcholine and phosphatidylglycerol in the cytosolic leaflet of the outer envelope membrane from spinach chloroplasts. When isolated, purified, intact chloroplasts were incubated with low amounts of phospholipase C (0.3 U/mg chlorophyll) under very mild conditions (12 degrees C for 1 min), greater than 80% of phosphatidylcholine molecules and almost none of phosphatidylglycerol molecules were hydrolyzed. Since we have also demonstrated, by using several different methods (phase-contrast and electron microscopy, immunochemical and electrophoretic analyses) that isolated spinach chloroplasts, and especially their outer envelope membrane, remained intact after mild treatment with phospholipase C, we can conclude that there is a marked asymmetric distribution of phospholipids across the outer envelope membrane of spinach chloroplasts. Phosphatidylcholine, the major polar lipid of the outer envelope membrane, is almost entirely accessible from the cytosolic side of the membrane and therefore is probably localized in the outer leaflet of the outer envelope bilayer. On the contrary, phosphatidylglycerol, the major polar lipid in the inner envelope membrane and the thylakoids, is probably not accessible to phospholipase C from the cytosol and therefore is probably localized mostly in the inner leaflet of the outer envelope membrane and in the other chloroplast membranes. PMID:3988805

  6. Nuclear envelope rupture drives genome instability in cancer

    PubMed Central

    Lim, Sanghee; Quinton, Ryan J.; Ganem, Neil J.

    2016-01-01

    The nuclear envelope, composed of two lipid bilayers and numerous accessory proteins, has evolved to house the genetic material of all eukaryotic cells. In so doing, the nuclear envelope provides a physical barrier between chromosomes and the cytoplasm. Once believed to be highly stable, recent studies demonstrate that the nuclear envelope is prone to rupture. These rupture events expose chromosomal DNA to the cytoplasmic environment and have the capacity to promote DNA damage. Thus nuclear rupture may be an unappreciated mechanism of mutagenesis. PMID:27799497

  7. The absolute energy flux envelopes of B type stars.

    NASA Technical Reports Server (NTRS)

    Underhill, A. B.

    1972-01-01

    Absolute energy flux envelopes covering the region of 1100 to 6000 A for main-sequence stars of types B3, B7 and A0 derived from published, ground-based observations and from spectrum scans with OAO-II are presented. These flux envelopes are compared with the predicted flux envelopes from lightly line-blanketed model atmospheres. The line blanketing at wavelengths shorter than 3000 A is severe, about one-half the predicted light being observed at 1600 A. These results demonstrate that a model which represents well the observed visible spectrum of a star may fail seriously for representing the ultraviolet spectrum.

  8. A recombinant envelope protein from Dengue virus purified by IMAC is bioequivalent with its immune-affinity chromatography purified counterpart.

    PubMed

    Hermida, L; Rodríguez, R; Lazo, L; López, C; Márquez, G; Páez, R; Suárez, C; Espinosa, R; García, J; Guzmán, G; Guillén, G

    2002-03-28

    Semi-purified DEN-4 envelope protein, obtained in Pichia pastoris, was capable of generating neutralising and protecting antibodies after immunisation in mice. Here we compared two purification processes of this recombinant protein using two chromatographic steps: immune-affinity chromatography and immobilised metal ion adsorption chromatography (IMAC). The protein purified by both methods produced functional antibodies reflected by titres of haemagglutination inhibition and neutralisation. IMAC could be used as an alternative for high scale purification.

  9. Differentiating founder and chronic HIV envelope sequences.

    PubMed

    Murray, John M; Maher, Stephen; Mota, Talia; Suzuki, Kazuo; Kelleher, Anthony D; Center, Rob J; Purcell, Damian

    2017-01-01

    Significant progress has been made in characterizing broadly neutralizing antibodies against the HIV envelope glycoprotein Env, but an effective vaccine has proven elusive. Vaccine development would be facilitated if common features of early founder virus required for transmission could be identified. Here we employ a combination of bioinformatic and operations research methods to determine the most prevalent features that distinguish 78 subtype B and 55 subtype C founder Env sequences from an equal number of chronic sequences. There were a number of equivalent optimal networks (based on the fewest covarying amino acid (AA) pairs or a measure of maximal covariance) that separated founders from chronics: 13 pairs for subtype B and 75 for subtype C. Every subtype B optimal solution contained the founder pairs 178-346 Asn-Val, 232-236 Thr-Ser, 240-340 Lys-Lys, 279-315 Asp-Lys, 291-792 Ala-Ile, 322-347 Asp-Thr, 535-620 Leu-Asp, 742-837 Arg-Phe, and 750-836 Asp-Ile; the most common optimal pairs for subtype C were 644-781 Lys-Ala (74 of 75 networks), 133-287 Ala-Gln (73/75) and 307-337 Ile-Gln (73/75). No pair was present in all optimal subtype C solutions highlighting the difficulty in targeting transmission with a single vaccine strain. Relative to the size of its domain (0.35% of Env), the α4β7 binding site occurred most frequently among optimal pairs, especially for subtype C: 4.2% of optimal pairs (1.2% for subtype B). Early sequences from 5 subtype B pre-seroconverters each exhibited at least one clone containing an optimal feature 553-624 (Ser-Asn), 724-747 (Arg-Arg), or 46-293 (Arg-Glu).

  10. Differentiating founder and chronic HIV envelope sequences

    PubMed Central

    Maher, Stephen; Mota, Talia; Suzuki, Kazuo; Kelleher, Anthony D.

    2017-01-01

    Significant progress has been made in characterizing broadly neutralizing antibodies against the HIV envelope glycoprotein Env, but an effective vaccine has proven elusive. Vaccine development would be facilitated if common features of early founder virus required for transmission could be identified. Here we employ a combination of bioinformatic and operations research methods to determine the most prevalent features that distinguish 78 subtype B and 55 subtype C founder Env sequences from an equal number of chronic sequences. There were a number of equivalent optimal networks (based on the fewest covarying amino acid (AA) pairs or a measure of maximal covariance) that separated founders from chronics: 13 pairs for subtype B and 75 for subtype C. Every subtype B optimal solution contained the founder pairs 178–346 Asn-Val, 232–236 Thr-Ser, 240–340 Lys-Lys, 279–315 Asp-Lys, 291–792 Ala-Ile, 322–347 Asp-Thr, 535–620 Leu-Asp, 742–837 Arg-Phe, and 750–836 Asp-Ile; the most common optimal pairs for subtype C were 644–781 Lys-Ala (74 of 75 networks), 133–287 Ala-Gln (73/75) and 307–337 Ile-Gln (73/75). No pair was present in all optimal subtype C solutions highlighting the difficulty in targeting transmission with a single vaccine strain. Relative to the size of its domain (0.35% of Env), the α4β7 binding site occurred most frequently among optimal pairs, especially for subtype C: 4.2% of optimal pairs (1.2% for subtype B). Early sequences from 5 subtype B pre-seroconverters each exhibited at least one clone containing an optimal feature 553–624 (Ser-Asn), 724–747 (Arg-Arg), or 46–293 (Arg-Glu). PMID:28187204

  11. Solubilization and reconstitution of vesicular stomatitis virus envelope using octylglucoside.

    PubMed Central

    Paternostre, M; Viard, M; Meyer, O; Ghanam, M; Ollivon, M; Blumenthal, R

    1997-01-01

    Reconstituted vesicular stomatitis virus envelopes or virosomes are formed by detergent removal from solubilized intact virus. We have monitored the solubilization process of the intact vesicular stomatitis virus by the nonionic surfactant octylglucoside at various initial virus concentrations by employing turbidity measurements. This allowed us to determine the phase boundaries between the membrane and the mixed micelles domains. We have also characterized the lipid and protein content of the solubilized material and of the reconstituted envelope. Both G and M proteins and all of the lipids of the envelope were extracted by octylglucoside and recovered in the reconstituted envelope. Fusion activity of the virosomes tested either on Vero cells or on liposomes showed kinetics and pH dependence similar to those of the intact virus. Images FIGURE 4 PMID:9083672

  12. Transport of Ions Across the Inner Envelope Membrane of Chloroplasts

    SciTech Connect

    McCarty, R. E.

    2004-06-02

    The technical report outlines the results of nine years of research on how ions cross the inner envelope membrane of chloroplasts. The ions include protons, nitrite, calcium and ferrous iron. Bicarbonate transport was also studied.

  13. A Systematic Approach to Evaluating the Building Envelope.

    ERIC Educational Resources Information Center

    Lindberg, Jon F.; Stewart, Edward J.; Morand, David A.

    2002-01-01

    Describes a process for evaluating a building's envelope (roof, walls, windows, waterproofing, and structure). Steps are grouped into the following categories: building history, field inspection, access methods, identifying defects, testing methods, and engineering analysis. (EV)

  14. Evolution of Space Shuttle Range Safety Ascent Flight Envelope Design

    NASA Technical Reports Server (NTRS)

    Brewer, Joan; Davis, Jerel; Glenn, Christopher

    2011-01-01

    For every space vehicle launch from the Eastern Range in Florida, the range user must provide specific Range Safety (RS) data products to the Air Force's 45th Space Wing in order to obtain flight plan approval. One of these data products is a set of RS ascent flight envelope trajectories that define the normal operating region of the vehicle during powered flight. With the Shuttle Program launching 135 manned missions over a 30-year period, 135 envelope sets were delivered to the range. During this time, the envelope methodology and design process evolved to support mission changes, maintain high data quality, and reduce costs. The purpose of this document is to outline the shuttle envelope design evolution and capture the lessons learned that could apply to future spaceflight endeavors.

  15. Testing Common Envelopes on Double White Dwarf Binaries

    NASA Astrophysics Data System (ADS)

    Nandez, Jose L. A.; Ivanova, Natalia; Lombardi, James C., Jr.

    2015-06-01

    The formation of a double white dwarf binary likely involves a common envelope (CE) event between a red giant and a white dwarf (WD) during the most recent episode of Roche lobe overflow mass transfer. We study the role of recombination energy with hydrodynamic simulations of such stellar interactions. We find that the recombination energy helps to expel the common envelope entirely, while if recombination energy is not taken into account, a significant fraction of the common envelope remains bound. We apply our numerical methods to constrain the progenitor system for WD 1101+364 - a double WD binary that has well-measured mass ratio of q=0.87±0.03 and an orbital period of 0.145 days. Our best-fit progenitor for the pre-common envelope donor is a 1.5 ⊙ red giant.

  16. Laboratory simulation of graphite formation in stellar envelopes

    NASA Technical Reports Server (NTRS)

    Dorfeld, W. G.; Hudson, J. B.

    1973-01-01

    A technique has been developed which permits laboratory simulation of graphite condensation in the envelopes of cool, late sequence stars. Processes in the stellar envelope were simulated by allowing hydrogen-carbon mixtures of typical circumstellar composition and temperature to expand freely into vacuum, cooling and supersaturating the vapor. Expansion products were determined mass spectrometrically through the use of molecular beam techniques. The results of laboratory expansions were scaled to those occurring near M and N stars by comparing the number of collisional events in each case. Kinetic considerations indicate that the important rate process in rarefied envelopes will be C2 formation; consequently scaling by termolecular collisions was employed. Results of this study imply that envelope expansions near M giants contribute at most .01 of the observed interstellar grain density. In the case of pulsating N stars, on the other hand, the results are not inconsistent with previous predictions of essentially complete carbon condensation.

  17. SIRT2 regulates nuclear envelope reassembly through ANKLE2 deacetylation

    PubMed Central

    Kaufmann, Tanja; Kukolj, Eva; Brachner, Andreas; Beltzung, Etienne; Bruno, Melania; Kostrhon, Sebastian; Opravil, Susanne; Hudecz, Otto; Mechtler, Karl; Warren, Graham

    2016-01-01

    ABSTRACT Sirtuin 2 (SIRT2) is an NAD-dependent deacetylase known to regulate microtubule dynamics and cell cycle progression. SIRT2 has also been implicated in the pathology of cancer, neurodegenerative diseases and progeria. Here, we show that SIRT2 depletion or overexpression causes nuclear envelope reassembly defects. We link this phenotype to the recently identified regulator of nuclear envelope reassembly ANKLE2. ANKLE2 acetylation at K302 and phosphorylation at S662 are dynamically regulated throughout the cell cycle by SIRT2 and are essential for normal nuclear envelope reassembly. The function of SIRT2 therefore extends beyond the regulation of microtubules to include the regulation of nuclear envelope dynamics. PMID:27875273

  18. Periodic envelopes of waves over non-uniform depth

    NASA Astrophysics Data System (ADS)

    Rajan, Girish K.; Bayram, Saziye; Henderson, Diane M.

    2016-04-01

    The envelope of narrow-banded, periodic, surface-gravity waves propagating in one dimension over water of finite, non-uniform depth may be modeled by the Djordjević and Redekopp ["On the development of packets of surface gravity waves moving over an uneven bottom," Z. Angew. Math. Phys. 29, 950-962 (1978)] equation (DRE). Here we find five approximate solutions of the DRE that are in the form of Jacobi-elliptic functions and discuss them within the framework of ocean swell. We find that in all cases, the maximum envelope-amplitude decreases/increases when the wave group propagates on water of decreasing/increasing depth. In the limit of the elliptic modulus approaching one, three of the solutions reduce to the envelope soliton solution. In the limit of the elliptic modulus approaching zero, two of the solutions reduce to an envelope-amplitude that is uniform in an appropriate reference frame.

  19. Beam envelope calculations in general linear coupled lattices

    SciTech Connect

    Chung, Moses; Qin, Hong; Groening, Lars; Xiao, Chen; Davidson, Ronald C.

    2015-01-15

    The envelope equations and Twiss parameters (β and α) provide important bases for uncoupled linear beam dynamics. For sophisticated beam manipulations, however, coupling elements between two transverse planes are intentionally introduced. The recently developed generalized Courant-Snyder theory offers an effective way of describing the linear beam dynamics in such coupled systems with a remarkably similar mathematical structure to the original Courant-Snyder theory. In this work, we present numerical solutions to the symmetrized matrix envelope equation for β which removes the gauge freedom in the matrix envelope equation for w. Furthermore, we construct the transfer and beam matrices in terms of the generalized Twiss parameters, which enables calculation of the beam envelopes in arbitrary linear coupled systems.

  20. RMS ENVELOPE BACK-PROPAGATION IN THE XAL ONLINE MODEL

    SciTech Connect

    Allen, Christopher K; Sako, Hiroyuki; Ikegami, Masanori

    2009-01-01

    The ability to back-propagate RMS envelopes was added to the J-PARC XAL online model. Specifically, given an arbitrary downstream location, the online model can propagate the RMS envelopes backward to an arbitrary upstream location. This feature provides support for algorithms estimating upstream conditions from downstream data. The upgrade required significant refactoring, which we outline. We also show simulations using the new feature.

  1. Advances in Understanding Durability of the Building Envelope: ORNL Research

    SciTech Connect

    Kehrer, Manfred; Desjarlais, Andre Omer

    2013-01-01

    Moisture, and its accompanying outriders things like mold, corrosion, freeze damage, and decay present powerful threats to the durability and long-term performance of a building envelope. Miscalculating the impact of environmental factors like rain, solar radiation, temperature, humidity, and indoor sources of moisture can cause significant damage to many types of building envelope components and materials, and also can lead to unhealthy indoor living environments.

  2. Universal enveloping crossed module of Leibniz crossed modules and representations

    NASA Astrophysics Data System (ADS)

    Casado, Rafael F.; García-Martínez, Xabier; Ladra, Manuel

    2016-03-01

    The universal enveloping algebra functor UL: Lb → Alg, defined by Loday and Pirashvili [1], is extended to crossed modules. Then we construct an isomorphism between the category of representations of a Leibniz crossed module and the category of left modules over its universal enveloping crossed module of algebras. Note that the procedure followed in the proof for the Lie case cannot be adapted, since the actor in the category of Leibniz crossed modules does not always exist.

  3. A Partial Differential Equation for the Rank One Convex Envelope

    NASA Astrophysics Data System (ADS)

    Oberman, Adam M.; Ruan, Yuanlong

    2017-02-01

    A partial differential equation (PDE) for the rank one convex envelope is introduced. The existence and uniqueness of viscosity solutions to the PDE is established. Elliptic finite difference schemes are constructed and convergence of finite difference solutions to the viscosity solution of the PDE is proven. Computational results are presented and laminates are computed from the envelopes. Results include the Kohn-Strang example, the classical four gradient example, and an example with eight gradients which produces nontrivial laminates.

  4. Disassembly of the cystovirus ϕ6 envelope by montmorillonite clay.

    PubMed

    Block, Karin A; Trusiak, Adrianna; Katz, Al; Gottlieb, Paul; Alimova, Alexandra; Wei, Hui; Morales, Jorge; Rice, William J; Steiner, Jeffrey C

    2014-02-01

    Prior studies of clay-virus interactions have focused on the stability and infectivity of nonenveloped viruses, yielding contradictory results. We hypothesize that the surface charge distribution of the clay and virus envelope dictates how the components react and affect aggregation, viral stability, and infectivity. The bacteriophage Cystoviridae species φ6 used in this study is a good model for enveloped pathogens. The interaction between φ6 and montmorillonite (MMT) clay (the primary component of bentonite) is explored by transmission electron microscopy. The analyses show that MMT-φ6 mixtures undergo heteroaggregation, forming structures in which virtually all the virions are either sequestered between MMT platelet layers or attached to platelet edges. The virions swell and undergo disassembly resulting in partial or total envelope loss. Edge-attached viral envelopes distort to increase contact area with the positively charged platelet edges indicating that the virion surface is negatively charged. The nucleocapsid (NCs) remaining after envelope removal also exhibit distortion, in contrast to detergent-produced NCs which exhibit no distortion. This visually discernible disassembly is a mechanism for loss of infectivity previously unreported by studies of nonenveloped viruses. The MMT-mediated sequestration and disassembly result in reduced infectivity, suggesting that clays may reduce infectivity of enveloped pathogenic viruses in soils and sediments.

  5. Preserving Envelope Efficiency in Performance Based Code Compliance

    SciTech Connect

    Thornton, Brian A.; Sullivan, Greg P.; Rosenberg, Michael I.; Baechler, Michael C.

    2015-06-20

    The City of Seattle 2012 Energy Code (Seattle 2014), one of the most progressive in the country, is under revision for its 2015 edition. Additionally, city personnel participate in the development of the next generation of the Washington State Energy Code and the International Energy Code. Seattle has pledged carbon neutrality by 2050 including buildings, transportation and other sectors. The United States Department of Energy (DOE), through Pacific Northwest National Laboratory (PNNL) provided technical assistance to Seattle in order to understand the implications of one potential direction for its code development, limiting trade-offs of long-lived building envelope components less stringent than the prescriptive code envelope requirements by using better-than-code but shorter-lived lighting and heating, ventilation, and air-conditioning (HVAC) components through the total building performance modeled energy compliance path. Weaker building envelopes can permanently limit building energy performance even as lighting and HVAC components are upgraded over time, because retrofitting the envelope is less likely and more expensive. Weaker building envelopes may also increase the required size, cost and complexity of HVAC systems and may adversely affect occupant comfort. This report presents the results of this technical assistance. The use of modeled energy code compliance to trade-off envelope components with shorter-lived building components is not unique to Seattle and the lessons and possible solutions described in this report have implications for other jurisdictions and energy codes.

  6. Name that percussive tune: Associative memory and amplitude envelope.

    PubMed

    Schutz, Michael; Stefanucci, Jeanine K; H Baum, Sarah; Roth, Amber

    2017-07-01

    A series of experiments demonstrated novel effects of amplitude envelope on associative memory, with tones exhibiting naturally decaying amplitude envelopes (e.g., those made by two wine glasses clinking) better associated with target objects than amplitude-invariant tones. In Experiment 1 participants learned associations between household objects and 4-note tone sequences constructed of spectrally matched pure tones with either "flat" or "percussive" amplitude envelopes. Those hearing percussive tones correctly recalled significantly more sequence-object associations. Experiment 2 demonstrated that participants hearing percussive tones learned the associations more quickly. Experiment 3 used "reverse percussive" tones (percussive tones played backwards) to test whether differences in overall energy might account for this effect, finding they did not lead to the same level of performance as percussive tones. Experiment 4 varied the envelope at encoding and retrieval to determine which stage of the task was most affected by the envelope manipulation. Participants hearing percussive tones at both encoding and retrieval performed significantly better than the other three groups (i.e., flat at encoding/percussive at retrieval, etc.). We conclude that amplitude envelope plays an important role in learning and memory, a finding with relevance to psychological research on audition and associative memory, as well as practical relevance for improving human-computer interface design.

  7. Disassembly of the cystovirus ϕ6 envelope by montmorillonite clay

    PubMed Central

    Block, Karin A; Trusiak, Adrianna; Katz, Al; Gottlieb, Paul; Alimova, Alexandra; Wei, Hui; Morales, Jorge; Rice, William J; Steiner, Jeffrey C

    2014-01-01

    Prior studies of clay–virus interactions have focused on the stability and infectivity of nonenveloped viruses, yielding contradictory results. We hypothesize that the surface charge distribution of the clay and virus envelope dictates how the components react and affect aggregation, viral stability, and infectivity. The bacteriophage Cystoviridae species φ6 used in this study is a good model for enveloped pathogens. The interaction between φ6 and montmorillonite (MMT) clay (the primary component of bentonite) is explored by transmission electron microscopy. The analyses show that MMT–φ6 mixtures undergo heteroaggregation, forming structures in which virtually all the virions are either sequestered between MMT platelet layers or attached to platelet edges. The virions swell and undergo disassembly resulting in partial or total envelope loss. Edge-attached viral envelopes distort to increase contact area with the positively charged platelet edges indicating that the virion surface is negatively charged. The nucleocapsid (NCs) remaining after envelope removal also exhibit distortion, in contrast to detergent-produced NCs which exhibit no distortion. This visually discernible disassembly is a mechanism for loss of infectivity previously unreported by studies of nonenveloped viruses. The MMT-mediated sequestration and disassembly result in reduced infectivity, suggesting that clays may reduce infectivity of enveloped pathogenic viruses in soils and sediments. PMID:24357622

  8. Protective Role of Ets1 in SLE

    DTIC Science & Technology

    2014-07-01

    Mycobacterium tuberculosis blocks crosslinking of annexin-1 and apoptotic envelope formation on infected macrophages to maintain virulence. Nat Immunol...and confer protection against multicellular parasitic infection (3, 4). Initially, IL-10 was reported as a typical Th2 cytokine (1). Recently, Th1...cells are the major source of host-protective reg- ulatory IL-10 during intracellular protozoan infection . J. Exp. Med. 204: 273–283. 8. Batten, M., N

  9. Phenylalanines at positions 88 and 159 of Ebolavirus envelope glycoprotein differentially impact envelope function

    SciTech Connect

    Ou Wu; King, Harlan; Delisle, Josie; Shi Dashuang; Wilson, Carolyn A.

    2010-01-05

    The envelope glycoprotein (GP) of Ebolavirus (EBOV) mediates viral entry into host cells. Through mutagenesis, we and other groups reported that two phenylalanines at positions 88 and 159 of GP are critical for viral entry. However, it remains elusive which steps of viral entry are impaired by F88 or F159 mutations and how. In this study, we further characterized these two phenylalanines through mutagenesis and examined the impact on GP expression, function, and structure. Our data suggest that F159 plays an indirect role in viral entry by maintaining EBOV GP's overall structure. In contrast, we did not detect any evidence for conformational differences in GP with F88 mutations. The data suggest that F88 influences viral entry during a step after cathepsin processing, presumably impacting viral fusion.

  10. Types of gaseous envelopes of "hot Jupiter" exoplanets

    NASA Astrophysics Data System (ADS)

    Bisikalo, D. V.; Kaigorodov, P. V.; Ionov, D. E.; Shematovich, V. I.

    2013-10-01

    As a rule, the orbital velocities of "hot Jupiters," i.e., exoplanets with masses comparable to the mass of Jupiter and orbital semi-major axes less than 0.1 AU, are supersonic relative to the stellar wind, resulting in the formation of a bow shock. Gas-dynamical modeling shows that the gaseous envelopes around hot Jupiters can belong to two classes, depending on the position of the collision point. if the collision point is inside the Roche lobe of the planet, the envelopes have the almost spherical shapes of classical atmospheres, slightly distorted by the influence of the star and interactions with the stellar-wind gas; if the collision point is located outside the Roche lobe, outflows from the vicinity of the Lagrangian points L1 and L2 arise, and the envelope becomes substantially asymmetrical. The latter class of objects can also be divided into two types. If the dynamical pressure of the stellar-wind gas is high enough to stop the most powerful outflow from the vicinity of the inner Lagrangian point L1, a closed quasi-spherical envelope with a complex shape forms in the system. If the wind is unable to stop the outflow from L1, an open aspherical envelope forms. The possible existence of atmospheres of these three types is confirmed by 3D numerical modeling. Using the typical hot Jupiter HD 209458b as an example, it is shown that all three types of atmospheres could exist within the range of estimated parameters of this planet. Since different types of envelopes have different observational manifestations, determining the type of envelope in HD 209458b could apply additional constrains on the parameters of this exoplanet.

  11. Metallicity dependence of envelope inflation in massive stars

    NASA Astrophysics Data System (ADS)

    Sanyal, D.; Langer, N.; Szécsi, D.; -C Yoon, S.; Grassitelli, L.

    2017-01-01

    Context. Recently it has been found that models of massive stars reach the Eddington limit in their interior, which leads to dilute extended envelopes. Aims: We perform a comparative study of the envelope properties of massive stars at different metallicities, with the aim to establish the impact of the stellar metallicity on the effect of envelope inflation. Methods: We analysed published grids of core-hydrogen burning massive star models computed with metallicities appropriate for massive stars in the Milky Way, the Large Magellanic Cloud, and the Small Magellanic Cloud, the very metal poor dwarf galaxy I Zwicky 18, and for metal-free chemical composition. Results: Stellar models of all the investigated metallicities reach and exceed the Eddington limit in their interior, aided by the opacity peaks of iron, helium, and hydrogen, and consequently develop inflated envelopes. Envelope inflation leads to a redward bending of the zero-age main sequence and a broadening of the main-sequence band in the upper part of the Hertzsprung-Russell diagram. We derive the limiting L/M-values as a function of the stellar surface temperature above which inflation occurs, and find them to be higher for lower metallicity. While Galactic models show inflation above 29 M⊙, the corresponding mass limit for Population III stars is 150 M⊙. While the masses of the inflated envelopes are generally low, we find that they can reach 1-100 M⊙ in models with effective temperatures below 8000 K, with higher masses reached by models of lower metallicity. Conclusions: Envelope inflation is expected to occur in sufficiently massive stars at all metallicities, and is expected to lead to rapidly growing pulsations, high macroturbulent velocities, and might well be related to the unexplained variability observed in luminous blue variables such as S Doradus and η Carina.

  12. Comparative Analysis of the Glycosylation Profiles of Membrane-Anchored HIV-1 Envelope Glycoprotein Trimers and Soluble gp140

    PubMed Central

    Go, Eden P.; Herschhorn, Alon; Gu, Christopher; Castillo-Menendez, Luis; Zhang, Shijian; Mao, Youdong; Chen, Haiyan; Ding, Haitao; Wakefield, John K.; Hua, David; Liao, Hua-Xin; Kappes, John C.; Sodroski, Joseph

    2015-01-01

    ABSTRACT The human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) trimer, which consists of the gp120 and gp41 subunits, is the focus of multiple strategies for vaccine development. Extensive Env glycosylation provides HIV-1 with protection from the immune system, yet the glycans are also essential components of binding epitopes for numerous broadly neutralizing antibodies. Recent studies have shown that when Env is isolated from virions, its glycosylation profile differs significantly from that of soluble forms of Env (gp120 or gp140) predominantly used in vaccine discovery research. Here we show that exogenous membrane-anchored Envs, which can be produced in large quantities in mammalian cells, also display a virion-like glycan profile, where the glycoprotein is extensively decorated with high-mannose glycans. Additionally, because we characterized the glycosylation with a high-fidelity profiling method, glycopeptide analysis, an unprecedented level of molecular detail regarding membrane Env glycosylation and its heterogeneity is presented. Each glycosylation site was characterized individually, with about 500 glycoforms characterized per Env protein. While many of the sites contain exclusively high-mannose glycans, others retain complex glycans, resulting in a glycan profile that cannot currently be mimicked on soluble gp120 or gp140 preparations. These site-level studies are important for understanding antibody-glycan interactions on native Env trimers. Additionally, we report a newly observed O-linked glycosylation site, T606, and we show that the full O-linked glycosylation profile of membrane-associated Env is similar to that of soluble gp140. These findings provide new insight into Env glycosylation and clarify key molecular-level differences between membrane-anchored Env and soluble gp140. IMPORTANCE A vaccine that protects against human immunodeficiency virus type 1 (HIV-1) infection should elicit antibodies that bind to the surface

  13. Optically thick envelopes around ULXs powered by accreating neutron stars

    NASA Astrophysics Data System (ADS)

    Mushtukov, Alexander A.; Suleimanov, Valery F.; Tsygankov, Sergey S.; Ingram, Adam

    2017-01-01

    Magnetized neutron stars power at least some ultra-luminous X-ray sources. The accretion flow in these cases is interrupted at the magnetospheric radius and then reaches the surface of a neutron star following magnetic field lines. Accreting matter moving along magnetic field lines forms the accretion envelope around the central object. We show that, in case of high mass accretion rates ≳ 1019 g s-1 the envelope becomes closed and optically thick, which influences the dynamics of the accretion flow and the observational manifestation of the neutron star hidden behind the envelope. Particularly, the optically thick accretion envelope results in a multi-color black-body spectrum originating from the magnetospheric surface. The spectrum and photon energy flux vary with the viewing angle, which gives rise to pulsations characterized by high pulsed fraction and typically smooth pulse profiles. The reprocessing of radiation due to interaction with the envelope leads to the disappearance of cyclotron scattering features from the spectrum. We speculate that the super-orbital variability of ultra-luminous X-ray sources powered by accreting neutron stars can be attributed to precession of the neutron star due to interaction of magnetic dipole with the accretion disc.

  14. Molecular biology of the baculovirus occlusion-derived virus envelope.

    PubMed

    Braunagel, Sharon C; Summers, Max D

    2007-10-01

    Study of the biology of the occlusion-derived virus (ODV) of the baculovirus Autographa californica nucleopolyhedrovirus provides opportunities to reveal new discoveries into the mechanism of several cellular pathways. The synchronous pulse of multiple ODV envelope proteins that integrate into the endoplasmic reticulum (ER) and traffic to the nuclear membranes on their way to the ODV envelope provide a unique tool to study the mechanisms of integral membrane protein trafficking from the ER to the outer and inner nuclear membrane. Studies of the formation of virus-induced, intranuclear membrane microvesicles provide insight on mechanisms that alter fluidity and regulate budding of the inner nuclear membrane. Since ODV is specially adapted for primary infection of the insect gut, studies of the structure and function of ODV envelope proteins reveals insights on the mechanism of viral invasion of the gut and this knowledge is fundamental for the development of new strategies for insect control. This review focuses on recent advances in understanding the source of the ODV envelope and the molecular events that sort and traffic integral membrane proteins from the ER to the ODV envelope. The composition of ODV is reviewed, however it is worth noting that the function of many ODV proteins are currently unknown.

  15. Virtual breakdown of the nuclear envelope in fission yeast meiosis.

    PubMed

    Asakawa, Haruhiko; Kojidani, Tomoko; Mori, Chie; Osakada, Hiroko; Sato, Mamiko; Ding, Da-Qiao; Hiraoka, Yasushi; Haraguchi, Tokuko

    2010-11-09

    Asymmetric localization of Ran regulators (RanGAP1 and RanGEF/RCC1) produces a gradient of RanGTP across the nuclear envelope. In higher eukaryotes, the nuclear envelope breaks down as the cell enters mitosis (designated "open" mitosis). This nuclear envelope breakdown (NEBD) leads to collapse of the RanGTP gradient and the diffusion of nuclear and cytoplasmic macromolecules in the cell, resulting in irreversible progression of the cell cycle. On the other hand, in many fungi, chromosome segregation takes place without NEBD (designated "closed" mitosis). Here we report that in the fission yeast Schizosaccharomyces pombe, despite the nuclear envelope and the nuclear pore complex remaining intact throughout both the meiotic and mitotic cell cycles, nuclear proteins diffuse into the cytoplasm transiently for a few minutes at the onset of anaphase of meiosis II. We also found that nuclear protein diffusion into the cytoplasm occurred coincidently with nuclear localization of Rna1, an S. pombe RanGAP1 homolog that is usually localized in the cytoplasm. These results suggest that nuclear localization of RanGAP1 and depression of RanGTP activity in the nucleus may be mechanistically tied to meiosis-specific diffusion of nuclear proteins into the cytoplasm. This nucleocytoplasmic shuffling of RanGAP1 and nuclear proteins represents virtual breakdown of the nuclear envelope.

  16. The ionization structure of the circumstellar envelope of Alpha Orionis

    NASA Technical Reports Server (NTRS)

    Glassgold, A. E.; Huggins, P. J.

    1986-01-01

    The physical processes which affect the ionization of the outer circumstellar envelope of Alpha Ori are analyzed and evaluated. The ultraviolet radiation fields of the chromosphere and the interstellar medium dominate the envelope, and the most common forms of all species are neutral atoms and first ions. Hydrogen recombines just outside the chromosphere, where atoms with smaller ionization potential are essentially fully ionized. The heavier ions gradually recombine with increasing distance from the star, until the interstellar radiation field reverses this trend. The electron fraction in the outer envelope is approximately equal to the abundance of all such heavy atoms, i.e., of the order of 0.0001. The analysis is applied to the case of neutral K, whose density in the envelope has been determined by scattering experiments. The theory predicts that the slope of the K I density distribution should decrease from -1.5 to -3.5 in the outer envelope. The mass loss rate of Alpha Ori implied by the K I scattering experiments is 4 x 10 to the -6th solar mass/yr.

  17. The South Carolina bridge-scour envelope curves

    USGS Publications Warehouse

    Benedict, Stephen T.; Feaster, Toby D.; Caldwell, Andral

    2016-09-30

    The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a series of three field investigations to evaluate historical, riverine bridge scour in the Piedmont and Coastal Plain regions of South Carolina. These investigations included data collected at 231 riverine bridges, which lead to the development of bridge-scour envelope curves for clear-water and live-bed components of scour. The application and limitations of the South Carolina bridge-scour envelope curves were documented in four reports, each report addressing selected components of bridge scour. The current investigation (2016) synthesizes the findings of these previous reports into a guidance manual providing an integrated procedure for applying the envelope curves. Additionally, the investigation provides limited verification for selected bridge-scour envelope curves by comparing them to field data collected outside of South Carolina from previously published sources. Although the bridge-scour envelope curves have limitations, they are useful supplementary tools for assessing the potential for scour at riverine bridges in South Carolina.

  18. Solar envelope concepts: moderate density building applications. Final report

    SciTech Connect

    Knowles, R.L.; Berry, R.D.

    1980-04-01

    Solar energy utilization in urban areas requires public guarantees that all property owners have direct access to the sun. The study examines the implications of this premise in relation to the need for cities to also encourage or accommodate rebuilding and future development. The public policy mechanism for guaranteeing solar access is conceptualized as a solar zoning envelope that allows the largest possible building bulk on a land parcel without shadowing neighboring properties during specified times. Step-by-step methods for generating solar envelopes are described with extensive drawings, showing a variety of urban platting and lot configurations. Development and design possibilities are examined on a selected set of Los Angeles sites with typically diverse urban characteristics. Envelope attributes suitable for encouraging moderate-density commercial and residential building are examined in the context of two hypothetical but realistic development programs: one for speculative office buildings and one for condominium housing. Numerous illustrations of envelope forms and prototypical building designs are provided. The results of development simulation studies on all test sites are tabulated to show building bulk, density, land-coverage and open space characteristics obtainable under the hypothesized envelopes.

  19. COMPLEX STRUCTURE IN CLASS 0 PROTOSTELLAR ENVELOPES. III. VELOCITY GRADIENTS IN NON-AXISYMMETRIC ENVELOPES, INFALL, OR ROTATION?

    SciTech Connect

    Tobin, John J.; Hartmann, Lee; Bergin, Edwin; Chiang, Hsin-Fang; Looney, Leslie W.; Maret, Sebastien

    2012-03-20

    We present an interferometric kinematic study of morphologically complex protostellar envelopes based on observations of the dense gas tracers N{sub 2}H{sup +} and NH{sub 3}. The strong asymmetric nature of most envelopes in our sample leads us to question the common interpretation of velocity gradients as rotation, given the possibility of projection effects in the observed velocities. Several 'idealized' sources with well-ordered velocity fields and envelope structures are now analyzed in more detail. We compare the interferometric data to position-velocity (PV) diagrams of kinematic models for spherical rotating collapse and filamentary rotating collapse. For this purpose, we developed a filamentary parameterization of the rotating collapse model to explore the effects of geometric projection on the observed velocity structures. We find that most envelopes in our sample have PV structures that can be reproduced by an infalling filamentary envelope projected at different angles within the plane of the sky. The infalling filament produces velocity shifts across the envelope that can mimic rotation, especially when viewed at single-dish resolutions and the axisymmetric rotating collapse model does not uniquely describe any data set. Furthermore, if the velocities are assumed to reflect rotation, then the inferred centrifugal radii are quite large in most cases, indicating significant fragmentation potential or more likely another component to the line-center velocity. We conclude that ordered velocity gradients cannot be interpreted as rotation alone when envelopes are non-axisymmetric and that projected infall velocities likely dominate the velocity field on scales larger than 1000 AU.

  20. Radiation Protection

    MedlinePlus

    Jump to main content US EPA United States Environmental Protection Agency Search Search Radiation Protection Share Facebook Twitter Google+ Pinterest Contact Us Radiation Protection Document Library View ...

  1. Chimeric hepatitis B virus (HBV)/hepatitis C virus (HCV) subviral envelope particles induce efficient anti-HCV antibody production in animals pre-immunized with HBV vaccine.

    PubMed

    Beaumont, Elodie; Roingeard, Philippe

    2015-02-18

    The development of an effective, affordable prophylactic vaccine against hepatitis C virus (HCV) remains a medical priority. The recently described chimeric HBV-HCV subviral envelope particles could potentially be used for this purpose, as they could be produced by industrial procedures adapted from those established for the hepatitis B virus (HBV) vaccine. We show here, in an animal model, that pre-existing immunity acquired through HBV vaccination does not influence the immunogenicity of the HCV E2 protein presented by these chimeric particles. Thus, these chimeric HBV-HCV subviral envelope particles could potentially be used as a booster in individuals previously vaccinated against HBV, to induce protective immunity to HCV.

  2. Simulating the onset of grazing envelope evolution of binary stars

    NASA Astrophysics Data System (ADS)

    Shiber, Sagiv; Kashi, Amit; Soker, Noam

    2017-02-01

    We present the first three-dimensional gas-dynamical simulations of the grazing envelope evolution (GEE) of stars, with the goal of exploring the basic flow properties and the role of jets at the onset of the GEE. In the simulated runs, a secondary main-sequence star grazes the envelope of the primary asymptotic giant branch (AGB) star. The orbit is circular at the radius of the AGB primary star on its equator. We inject two opposite jets perpendicular to the equatorial plane from the location of the secondary star, and follow the evolution for several orbital periods. We explore the flow pattern by which the jets eject the outskirts of the AGB envelope. After one orbit, the jets start to interact with gas ejected in previous orbits and inflate hot low-density bubbles.

  3. Second-order envelope equation of graphene electrons

    NASA Astrophysics Data System (ADS)

    Luo, Ji

    2014-10-01

    A treatment of graphene's electronic states based on the tight-binding method is presented. Like Dirac equation, this treatment uses envelope functions to eliminate crystal potential. Besides, a density-functional-theory Kohn-Sham (KS) orbital of an isolated carbon atom is employed. By locally expanding envelope functions into second-order polynomials and by involving up to third-nearest atoms in calculating orbital integrals, the second-order envelope equation is obtained. This equation does not contain any experimental data except graphene's crystal structure, and its coefficients are determined through several kinds of integrals of the carbon KS orbital. As an improvement, it leads to more accurate energy dispersion than Dirac equation including the triangular warping effect and asymmetry for electrons and holes, and gives the Fermi velocity which is in good agreement with the experimental value.

  4. Classification of oscillometric envelope shape using frequent sequence mining.

    PubMed

    Diao, Hung-Wen; Hu, Weichih; Lan, Gong-Yau; Shyu, Liang-Yu

    2013-01-01

    The shape of the oscillometric envelope is known to affect the accuracy of automatic noninvasive blood pressure (NIBP) measurement devices that use the oscillometric principle to determine systolic and diastolic blood pressures. This study proposes a novel shape classification method that uses data mining techniques to determine the characteristic sequences for different envelope shapes. The results indicate that the proposed method effectively determines the characteristic sequences for different subject groups. Subjects in the high- score group and in the low- score group tend to have an envelope with a broader plateau and are bell-shaped, respectively. This information about shape can be used for future determination of the correct algorithm for systolic and diastolic blood pressures determination in NIBP devices.

  5. Structure of Phage P22 Cell Envelope-Penetrating Needle

    SciTech Connect

    Olia,A.; Casjens, S.; Cingolani, G.

    2007-01-01

    Bacteriophage P22 infects Salmonella enterica by injecting its genetic material through the cell envelope. During infection, a specialized tail needle, gp26, is injected into the host, likely piercing a hole in the host cell envelope. The 2.1-Angstroms crystal structure of gp26 reveals a 240-Angstroms elongated protein fiber formed by two trimeric coiled-coil domains interrupted by a triple beta-helix. The N terminus of gp26 plugs the portal protein channel, retaining the genetic material inside the virion. The C-terminal tip of the fiber exposes beta-hairpins with hydrophobic tips similar to those seen in class II fusion peptides. The alpha-helical core connecting these two functionally polarized tips presents four trimerization octads with consensus sequence IXXLXXXV. The slender conformation of the gp26 fiber minimizes the surface exposed to solvent, which is consistent with the idea that gp26 traverses the cell envelope lipid bilayers.

  6. The envelope Hamiltonian for electron interaction with ultrashort pulses

    NASA Astrophysics Data System (ADS)

    Toyota, Koudai; Saalmann, Ulf; Rost, Jan M.

    2015-07-01

    For ultrashort VUV pulses with a pulse length comparable to the orbital time of the bound electrons they couple to, we propose a simplified envelope Hamiltonian. It is based on the Kramers-Henneberger representation in connection with a Floquet expansion of the strong-field dynamics but keeps the time dependence of the pulse envelope explicit. Thereby, the envelope Hamiltonian captures the essence of the physics—light-induced shifts of bound states, single-photon absorption, and non-adiabatic electronic transitions. It delivers quantitatively accurate ionization dynamics and allows for a physical insight into the processes occurring. Its minimal requirements for construction in terms of laser parameters make it ideally suited for a large class of atomic and molecular problems.

  7. Structure of Phage P22 Cell Envelope-Penetrating Needle

    SciTech Connect

    Olia, A.S.; Casjens, S.; Cingolani, G.

    2009-06-02

    Bacteriophage P22 infects Salmonella enterica by injecting its genetic material through the cell envelope. During infection, a specialized tail needle, gp26, is injected into the host, likely piercing a hole in the host cell envelope. The 2.1-{angstrom} crystal structure of gp26 reveals a 240-{angstrom} elongated protein fiber formed by two trimeric coiled-coil domains interrupted by a triple {beta}-helix. The N terminus of gp26 plugs the portal protein channel, retaining the genetic material inside the virion. The C-terminal tip of the fiber exposes {beta}-hairpins with hydrophobic tips similar to those seen in class II fusion peptides. The {alpha}-helical core connecting these two functionally polarized tips presents four trimerization octads with consensus sequence IXXLXXXV. The slender conformation of the gp26 fiber minimizes the surface exposed to solvent, which is consistent with the idea that gp26 traverses the cell envelope lipid bilayers.

  8. Method and apparatus for controlling carrier envelope phase

    DOEpatents

    Chang, Zenghu [Manhattan, KS; Li, Chengquan [Sunnyvale, CA; Moon, Eric [Manhattan, KS

    2011-12-06

    A chirped pulse amplification laser system. The system generally comprises a laser source, a pulse modification apparatus including first and second pulse modification elements separated by a separation distance, a positioning element, a measurement device, and a feedback controller. The laser source is operable to generate a laser pulse and the pulse modification apparatus operable to modify at least a portion of the laser pulse. The positioning element is operable to reposition at least a portion of the pulse modification apparatus to vary the separation distance. The measurement device is operable to measure the carrier envelope phase of the generated laser pulse and the feedback controller is operable to control the positioning element based on the measured carrier envelope phase to vary the separation distance of the pulse modification elements and control the carrier envelope phase of laser pulses generated by the laser source.

  9. Autopresentation of hepatitis B virus envelope antigens by T cells.

    PubMed Central

    Ferrari, C; Pilli, M; Penna, A; Bertoletti, A; Valli, A; Cavalli, A; Pasetti, G; Fiaccadori, F

    1992-01-01

    Processing and presentation by T cells appear to be limited to antigens that can directly interact with the T-cell surface, thereby overcoming the T-cell inefficiency in antigen capture and internalization. Our study provides evidence that the hepatitis B virus (HBV) envelope proteins can also be efficiently processed and presented by CD4+ and CD8+ T cells to other T cells in a human leukocyte antigen class II-restricted fashion. This phenomenon suggests a receptor-mediated interaction between T cells and the HBV envelope and defines a system that can, we hope, be exploited for the identification of the receptor binding site within the HBV envelope and for the characterization of the putative cellular HBV receptor. PMID:1548778

  10. Nuclear envelope fission is linked to cytokinesis in budding yeast.

    PubMed

    Lippincott, J; Li, R

    2000-11-01

    We have investigated the relationship between nuclear envelope fission and cytokinesis during mitotic cell division in budding yeast. By carrying out time-lapse and optical sectioning video microscopy analysis of cells that express green fluorescent protein (GFP)-tagged nuclear envelope and actomyosin ring components, we found that nuclear division is temporally coupled to cytokinesis. Light and electron microscopy analysis also showed that nuclear envelope fission and the division of the nucleoplasm are severely delayed in cytokinesis mutants, resulting in discoupling between the nuclear division cycle and the budding cycle. These results suggest that homotypic membrane fusion may be activated by components or the mechanical action of cytokinetic structures and presents a mechanism for the equal partitioning of the nucleus and the temporal coordination of this event with chromosome segregation during mitosis.

  11. Photochemistry and molecular ions in carbon-rich circumstellar envelopes

    NASA Technical Reports Server (NTRS)

    Glassgold, A. E.; Mamon, G. A.; Omont, A.; Lucas, R.

    1987-01-01

    An earlier theory of ionization of C-rich circumstellar envelopes based on the photochemical model is extended to include the temperature dependence of ion-molecule reactions with polar molecules, particularly HCN, and line self-shielding of CO dissociating radiation. The results are applied to the abundances of HCO(+) and HNC in C-rich circumstellar envelopes. With standard parameters for IRC + 10216, the model is found to be consistent with the new upper limit to the antenna temperature of the J = 1-0 line of HCO(+) obtained with the IRAM 30-m telescope. The photochemical model provides a natural explanation of the relatively large ratio of HCN to HNC observed for C-rich circumstellar envelopes, and good agreement is obtained for the H(C-13)N/HNC antenna temperature ratio measured for IRC + 10216.

  12. PAH formation in carbon-rich circumstellar envelopes

    NASA Technical Reports Server (NTRS)

    Feigelson, Eric D.; Frenklach, Michael

    1989-01-01

    While there is growing observational evidence that some fraction of interstellar carbon is in polycyclic aromatic hydrocarbons (PAH's), the mechanisms by which these molecules might be formed have not been extensively studied. A detailed investigation of PAH production in the outflowing molecular envelopes of carbon-rich red giant star is presented. The gasphase kinetics of a chemical reaction mechanism developed to study soot production in hydrocarbon flames is modified to apply in circumstellar environments. It was found that astrophysically significant quantities of PAH's can be formed in carbon star envelopes provided the gas is sufficiently dense and resides for a long time in the temperature range of 900 to 1100 k. The precise yield of PAH's is very sensitive to astronomical parameters of the envelope (e.g., mass loss rate, outflow velocity, and acetylene abundance) and certain poorly determined chemical reaction rates.

  13. Efficiency of planetesimal ablation in giant planetary envelopes

    NASA Astrophysics Data System (ADS)

    Pinhas, Arazi; Madhusudhan, Nikku; Clarke, Cathie

    2016-12-01

    Observations of exoplanetary spectra are leading to unprecedented constraints on their atmospheric elemental abundances, particularly O/H, C/H, and C/O ratios. Recent studies suggest that elemental ratios could provide important constraints on formation and migration mechanisms of giant exoplanets. A fundamental assumption in such studies is that the chemical composition of the planetary envelope represents the sum-total of compositions of the accreted gas and solids during the formation history of the planet. We investigate the efficiency with which accreted planetesimals ablate in a giant planetary envelope thereby contributing to its composition rather than sinking to the core. From considerations of aerodynamic drag causing `frictional ablation' and the envelope temperature structure causing `thermal ablation', we compute mass ablations for impacting planetesimals of radii 30 m to 1 km for different compositions (ice to iron) and a wide range of velocities and impact angles, assuming spherical symmetry. Icy impactors are fully ablated in the outer envelope for a wide range of parameters. Even for Fe impactors substantial ablation occurs in the envelope for a wide range of sizes and velocities. For example, iron impactors of sizes below ˜0.5 km and velocities above ˜30 km s-1 are found to ablate by ˜60-80 per cent within the outer envelope at pressures below 103 bar due to frictional ablation alone. For deeper pressures (˜107 bar), substantial ablation happens over a wider range of parameters. Therefore, our exploratory study suggests that atmospheric abundances of volatile elements in giant planets reflect their accretion history during formation.

  14. Repairing oxidized proteins in the bacterial envelope using respiratory chain electrons.

    PubMed

    Gennaris, Alexandra; Ezraty, Benjamin; Henry, Camille; Agrebi, Rym; Vergnes, Alexandra; Oheix, Emmanuel; Bos, Julia; Leverrier, Pauline; Espinosa, Leon; Szewczyk, Joanna; Vertommen, Didier; Iranzo, Olga; Collet, Jean-François; Barras, Frédéric

    2015-12-17

    The reactive species of oxygen and chlorine damage cellular components, potentially leading to cell death. In proteins, the sulfur-containing amino acid methionine is converted to methionine sulfoxide, which can cause a loss of biological activity. To rescue proteins with methionine sulfoxide residues, living cells express methionine sulfoxide reductases (Msrs) in most subcellular compartments, including the cytosol, mitochondria and chloroplasts. Here we report the identification of an enzymatic system, MsrPQ, repairing proteins containing methionine sulfoxide in the bacterial cell envelope, a compartment particularly exposed to the reactive species of oxygen and chlorine generated by the host defence mechanisms. MsrP, a molybdo-enzyme, and MsrQ, a haem-binding membrane protein, are widely conserved throughout Gram-negative bacteria, including major human pathogens. MsrPQ synthesis is induced by hypochlorous acid, a powerful antimicrobial released by neutrophils. Consistently, MsrPQ is essential for the maintenance of envelope integrity under bleach stress, rescuing a wide series of structurally unrelated periplasmic proteins from methionine oxidation, including the primary periplasmic chaperone SurA. For this activity, MsrPQ uses electrons from the respiratory chain, which represents a novel mechanism to import reducing equivalents into the bacterial cell envelope. A remarkable feature of MsrPQ is its capacity to reduce both rectus (R-) and sinister (S-) diastereoisomers of methionine sulfoxide, making this oxidoreductase complex functionally different from previously identified Msrs. The discovery that a large class of bacteria contain a single, non-stereospecific enzymatic complex fully protecting methionine residues from oxidation should prompt a search for similar systems in eukaryotic subcellular oxidizing compartments, including the endoplasmic reticulum.

  15. Repairing oxidized proteins in the bacterial envelope using respiratory chain electrons

    PubMed Central

    Henry, Camille; Agrebi, Rym; Vergnes, Alexandra; Oheix, Emmanuel; Bos, Julia; Leverrier, Pauline; Espinosa, Leon; Szewczyk, Joanna; Vertommen, Didier; Iranzo, Olga; Collet, Jean-François; Barras, Frédéric

    2015-01-01

    The reactive species of oxygen (ROS) and chlorine (RCS) damage cellular components, potentially leading to cell death. In proteins, the sulfur-containing amino acid methionine (Met) is converted to methionine sulfoxide (Met-O), which can cause a loss of biological activity. To rescue proteins with Met-O residues, living cells express methionine sulfoxide reductases (Msrs) in most subcellular compartments, including the cytosol, mitochondria and chloroplasts 1-3. Here, we report the identification of an enzymatic system, MsrPQ, repairing Met-O containing proteins in the bacterial cell envelope, a compartment particularly exposed to the ROS and RCS generated by the host defense mechanisms. MsrP, a molybdo-enzyme, and MsrQ, a heme-binding membrane protein, are widely conserved throughout Gram-negative bacteria, including major human pathogens. MsrPQ synthesis is induced by hypochlorous acid (HOCl), a powerful antimicrobial released by neutrophils. Consistently, MsrPQ is essential for the maintenance of envelope integrity under bleach stress, rescuing a wide series of structurally unrelated periplasmic proteins from Met oxidation, including the primary periplasmic chaperone SurA. For this activity, MsrPQ uses electrons from the respiratory chain, which represents a novel mechanism to import reducing equivalents into the bacterial cell envelope. A remarkable feature of MsrPQ is its capacity to reduce both R- and S- diastereoisomers of Met-O, making this oxidoreductase complex functionally different from previously identified Msrs. The discovery that a large class of bacteria contain a single, non-stereospecific enzymatic complex fully protecting Met residues from oxidation should prompt search for similar systems in eukaryotic subcellular oxidizing compartments, including the endoplasmic reticulum (ER). PMID:26641313

  16. The dynamic nature of the nuclear envelope: lessons from closed mitosis.

    PubMed

    Arnone, James T; Walters, Alison D; Cohen-Fix, Orna

    2013-01-01

    In eukaryotes, chromosomes are encased by a dynamic nuclear envelope. In contrast to metazoans, where the nuclear envelope disassembles during mitosis, many fungi including budding yeast undergo "closed mitosis," where the nuclear envelope remains intact throughout the cell cycle. Consequently, during closed mitosis the nuclear envelope must expand to accommodate chromosome segregation to the two daughter cells. A recent study by Witkin et al. in budding yeast showed that if progression through mitosis is delayed, for example due to checkpoint activation, the nuclear envelope continues to expand despite the block to chromosome segregation. Moreover, this expansion occurs at a specific region of the nuclear envelope- adjacent to the nucleolus- forming an extension referred to as a "flare." These observations raise questions regarding the regulation of nuclear envelope expansion both in budding yeast and in higher eukaryotes, the mechanisms confining mitotic nuclear envelope expansion to a particular region and the possible consequences of failing to regulate nuclear envelope expansion during the cell cycle.

  17. Maximum Torque and Momentum Envelopes for Reaction Wheel Arrays

    NASA Technical Reports Server (NTRS)

    Reynolds, R. G.; Markley, F. Landis

    2001-01-01

    Spacecraft reaction wheel maneuvers are limited by the maximum torque and/or angular momentum which the wheels can provide. For an n-wheel configuration, the torque or momentum envelope can be obtained by projecting the n-dimensional hypercube, representing the domain boundary of individual wheel torques or momenta, into three dimensional space via the 3xn matrix of wheel axes. In this paper, the properties of the projected hypercube are discussed, and algorithms are proposed for determining this maximal torque or momentum envelope for general wheel configurations. Practical implementation strategies for specific wheel configurations are also considered.

  18. Intracranial treatment envelope mapping of transcranial focused ultrasound

    NASA Astrophysics Data System (ADS)

    Eames, Matthew D. C.; Hananel, Arik; Kassell, Neal F.; Snell, John W.

    2012-11-01

    Presented here are the results of a volumetric, thermal treatment envelope map for transcranial focused ultrasound. The aim was to determine the treatable volume of the intracranial cavity in order to identify potential clinical applications and direct future research efforts. It was determined that thalamic targets are optimal for both transcranical MRg-FUS systems used in this work, which operate at 220 kHz and 650 kHz, respectively. It is hoped that future research efforts will focus on expanding these treatment envelopes in order to expand the possible neurosurgical applications for this technology.

  19. Planetesimal dissolution in the envelopes of the forming, giant planets

    NASA Technical Reports Server (NTRS)

    Pollack, J. B.; Podolak, M.; Bodenheimer, P.; Christofferson, B.

    1986-01-01

    An evaluation is made of the capacity of planetesimals to penetrate the envelopes of giant planets during their growth phase, by means of a core instability mechanism in which the growing core becomes gradually more adept in the gravitational concentration of gas from its solar nebula environment, until a runaway gas accretion occurs. If most of the accreted mass is contained in planetesimals larger that about 1 km, the critical core mass for runaway accretion will not significantly change when planetesimal dissolution is taken into account; it is accordingly suggested that giant planet envelopes should contain above-solar proportions of virtually all elements, relative to hydrogen.

  20. Role of Envelopment in the HEV Life Cycle

    PubMed Central

    Yin, Xin; Li, Xinlei; Feng, Zongdi

    2016-01-01

    Hepatitis E virus (HEV), an enterically transmitted hepatotropic virus, was thought to be non-enveloped for decades. However, recent studies have revealed that the virus circulating in the patient’s blood is completely cloaked in host membranes and resistant to neutralizing antibodies. The discovery of this novel enveloped form of HEV has raised a series of questions about the fundamental biology of HEV and the way this virus, which has been understudied in the past, interacts with its host. Here, we review recent advances towards understanding this phenomenon and discuss its potential impact on various aspects of the HEV life cycle and immunity. PMID:27548201

  1. Photochemistry and molecular ions in oxygen-rich circumstellar envelopes

    NASA Technical Reports Server (NTRS)

    Mamon, G. A.; Glassgold, A. E.; Omont, A.

    1987-01-01

    A theory for the ionization of the circumstellar envelopes around O-rich red giants is developed from the photochemical model. The main source of ionization is photoionization of H2O, OH, and C by the interstellar UV radiation field, supplemented by cosmic-ray ionization of hydrogen. Significant amounts of H3O(+) and HCO(+) are produced, with peak abundances of about 10 to the -7th at intermediate distances from the star. Although H3O(+) may be difficult to detect with current instrumentation, HCO(+) is probably detectable in nearby O-rich envelopes with large millimeter-wave telescopes.

  2. A Phase-Change Composite for Use in Building Envelopes

    SciTech Connect

    Graves, Ron S.

    1992-06-15

    The objective of this project is to develop composite thermal insulations containing phase-change materials for use in the building envelope. The use of a phase-change insulation composite in the building envelope could result in a significant increase in energy efficiency. PhD Research provided candidate phase-change composites, and ORNL performed analytical and experimental evaluations of their thermal performance. The thermal resistance of the prototype panels was somewhat less than that of commercial products, although their thermal capacity was greater. Using these results, PhD Research has been working to modify the design and to produce practical building elements that incorporate phase-change material.

  3. HIV envelope: challenges and opportunities for development of entry inhibitors

    PubMed Central

    Caffrey, Michael

    2011-01-01

    The HIV envelope proteins gp120 and gp41 play critical roles in HIV entry and thus are of extreme interest for the development of novel therapeutics. Study by diverse methods, including structural biology and mutagenesis, has resulted in a detailed model for envelope-mediated entry, which consists of multiple conformations, each a potential target for therapeutic intervention. In this review we discuss the challenges, strategies and progress to date for developing novel entry inhibitors directed at disrupting HIV gp120 and gp41 function. PMID:21377881

  4. Selective Gammatone Envelope Feature for Robust Sound Event Recognition

    NASA Astrophysics Data System (ADS)

    Leng, Yi Ren; Tran, Huy Dat; Kitaoka, Norihide; Li, Haizhou

    Conventional features for Automatic Speech Recognition and Sound Event Recognition such as Mel-Frequency Cepstral Coefficients (MFCCs) have been shown to perform poorly in noisy conditions. We introduce an auditory feature based on the gammatone filterbank, the Selective Gammatone Envelope Feature (SGEF), for Robust Sound Event Recognition where channel selection and the filterbank envelope is used to reduce the effect of noise for specific noise environments. In the experiments with Hidden Markov Model (HMM) recognizers, we shall show that our feature outperforms MFCCs significantly in four different noisy environments at various signal-to-noise ratios.

  5. Serial femtosecond X-ray diffraction of enveloped virus microcrystals

    DOE PAGES

    Lawrence, Robert M.; Conrad, Chelsie E.; Zatsepin, Nadia A.; ...

    2015-08-20

    Serial femtosecond crystallography (SFX) using X-ray free-electron lasers has produced high-resolution, room temperature, time-resolved protein structures. We report preliminary SFX of Sindbis virus, an enveloped icosahedral RNA virus with ~700 Å diameter. Microcrystals delivered in viscous agarose medium diffracted to ~40 Å resolution. Small-angle diffuse X-ray scattering overlaid Bragg peaks and analysis suggests this results from molecular transforms of individual particles. Viral proteins undergo structural changes during entry and infection, which could, in principle, be studied with SFX. This is a pertinent step toward determining room temperature structures from virus microcrystals that may enable time-resolved studies of enveloped viruses.

  6. Formation of Jupiter's Core and Early Stages of Envelope Accretion

    NASA Astrophysics Data System (ADS)

    D'Angelo, G.; Weidenschilling, S.; Lissauer, J. J.; Bodenheimer, P.; Hubickyj, O.

    2012-12-01

    We are performing calculations of the formation of Jupiter via core nucleated accretion and gas capture. The core starts as a seed body of a few hundred kilometers in radius and orbits within a swarm of planetesimals whose initial size distribution ranges from ~10 m to ~100 km. The planetesimals are immersed in a gaseous disk, representative of an early solar nebula. The evolution of the swarm of planetesimals accounts for collisions and gravitational stirring due to mutual interactions among bodies, and for migration and velocity damping due to interactions with the nebula gas. Collisions among planetesimals lead to growth and/or fragmentation, altering the size distribution of the swarm over time. Collisions of planetesimals with the seed body lead to its growth, resulting in the formation of a planetary core. Gas capture by the core leads to the accumulation of a tenuous atmosphere, which later becomes a massive envelope, increasing the size-dependent effective cross-section of the planet for planetesimals' accretion. Planetesimals that travel through the core's envelope release energy, affecting the thermal budget of the envelope, and deliver mass, affecting the opacity of the envelope. The calculation of dust opacity, which is especially important for envelope contraction, is performed self-consistently, accounting for coagulation and sedimentation of dust and small particles that are released in the envelope as passing planetesimals are ablated. We find that, in a disk of planetesimals with a surface density of about 10 g/cm2 at 5.2 AU, a one Earth mass core accumulates in less than 1e5 years, and that it takes over 1.5e6 years to accumulate a core of 3 Earth masses, when the core's geometrical cross-section is used for the accretion of planetesimals. Gas drag in the core's envelope increases the ability of the planet to accrete planetesimals. Smaller planetesimals are affected to a greater extent than are larger planetesimals. We find that the effective

  7. Refractive index dispersion measurement using carrier-envelope phasemeters

    NASA Astrophysics Data System (ADS)

    Hansinger, Peter; Töpfer, Philipp; Dimitrov, Nikolay; Adolph, Daniel; Hoff, Dominik; Rathje, Tim; Sayler, A. Max; Dreischuh, Alexander; Paulus, Gerhard G.

    2017-02-01

    We introduce a novel method for direct and accurate measurement of refractive index dispersion based on carrier-envelope phase detection of few-cycle laser pulses, exploiting the difference between phase and group velocity in a dispersive medium. In a layout similar to an interferometer, two carrier-envelope phasemeters are capable of measuring the dispersion of a transparent or reflective sample, where one phasemeter serves as the reference and the other records the influence of the sample. Here we report on proof-of-principle measurements that already reach relative uncertainties of a few 10‑4. Further development is expected to allow for unprecedented precision.

  8. A Mycobacterium tuberculosis Sigma Factor Network Responds to Cell-Envelope Damage by the Promising Anti-Mycobacterial Thioridazine

    PubMed Central

    Dutta, Noton K.; Mehra, Smriti; Kaushal, Deepak

    2010-01-01

    Background Novel therapeutics are urgently needed to control tuberculosis (TB). Thioridazine (THZ) is a candidate for the therapy of multidrug and extensively drug-resistant TB. Methodology/Principal Findings We studied the impact of THZ on Mycobacterium tuberculosis (Mtb) by analyzing gene expression profiles after treatment at the minimal inhibitory (1x MIC) or highly inhibitory (4x MIC) concentrations between 1–6 hours. THZ modulated the expression of genes encoding membrane proteins, efflux pumps, oxido-reductases and enzymes involved in fatty acid metabolism and aerobic respiration. The Rv3160c-Rv3161c operon, a multi-drug transporter and the Rv3614c/3615c/3616c regulon, were highly induced in response to THZ. A significantly high number of Mtb genes co-expressed with σB (the σB regulon) was turned on by THZ treatment. σB has recently been shown to protect Mtb from envelope-damage. We hypothesized that THZ damages the Mtb cell-envelope, turning on the expression of the σB regulon. Consistent with this hypothesis, we present electron-microscopy data which shows that THZ modulates cell-envelope integrity. Moreover, the Mtb mutants in σH and σE, two alternate stress response sigma factors that induce the expression of σB, exhibited higher sensitivity to THZ, indicating that the presence and expression of σB allows Mtb to resist the impact of THZ. Conditional induction of σB levels increased the survival of Mtb in the presence of THZ. Conclusions/Significance THZ targets different pathways and can thus be used as a multi-target inhibitor itself as well as provide strategies for multi-target drug development for combination chemotherapy. Our results show that the Mtb sigma factor network comprising of σH, σE and σB plays a crucial role in protecting the pathogen against cell-envelope damage. PMID:20386700

  9. Insights into the Function of YciM, a Heat Shock Membrane Protein Required To Maintain Envelope Integrity in Escherichia coli

    PubMed Central

    Nicolaes, Valérie; El Hajjaji, Hayat; Davis, Rebecca M.; Van der Henst, Charles; Depuydt, Matthieu; Leverrier, Pauline; Aertsen, Abram; Haufroid, Vincent; Ollagnier de Choudens, Sandrine; De Bolle, Xavier; Ruiz, Natividad

    2013-01-01

    The cell envelope of Gram-negative bacteria is an essential organelle that is important for cell shape and protection from toxic compounds. Proteins involved in envelope biogenesis are therefore attractive targets for the design of new antibacterial agents. In a search for new envelope assembly factors, we screened a collection of Escherichia coli deletion mutants for sensitivity to detergents and hydrophobic antibiotics, a phenotype indicative of defects in the cell envelope. Strains lacking yciM were among the most sensitive strains of the mutant collection. Further characterization of yciM mutants revealed that they display a thermosensitive growth defect on low-osmolarity medium and that they have a significantly altered cell morphology. At elevated temperatures, yciM mutants form bulges containing cytoplasmic material and subsequently lyse. We also discovered that yciM genetically interacts with envC, a gene encoding a regulator of the activity of peptidoglycan amidases. Altogether, these results indicate that YciM is required for envelope integrity. Biochemical characterization of the protein showed that YciM is anchored to the inner membrane via its N terminus, the rest of the protein being exposed to the cytoplasm. Two CXXC motifs are present at the C terminus of YciM and serve to coordinate a redox-sensitive iron center of the rubredoxin type. Both the N-terminal membrane anchor and the C-terminal iron center of YciM are important for function. PMID:24187084

  10. Human broadly neutralizing antibodies to the envelope glycoprotein complex of hepatitis C virus.

    PubMed

    Giang, Erick; Dorner, Marcus; Prentoe, Jannick C; Dreux, Marlène; Evans, Matthew J; Bukh, Jens; Rice, Charles M; Ploss, Alexander; Burton, Dennis R; Law, Mansun

    2012-04-17

    Hepatitis C virus (HCV) infects ∼2% of the world's population. It is estimated that there are more than 500,000 new infections annually in Egypt, the country with the highest HCV prevalence. An effective vaccine would help control this expanding global health burden. HCV is highly variable, and an effective vaccine should target conserved T- and B-cell epitopes of the virus. Conserved B-cell epitopes overlapping the CD81 receptor-binding site (CD81bs) on the E2 viral envelope glycoprotein have been reported previously and provide promising vaccine targets. In this study, we isolated 73 human mAbs recognizing five distinct antigenic regions on the virus envelope glycoprotein complex E1E2 from an HCV-immune phage-display antibody library by using an exhaustive-panning strategy. Many of these mAbs were broadly neutralizing. In particular, the mAb AR4A, recognizing a discontinuous epitope outside the CD81bs on the E1E2 complex, has an exceptionally broad neutralizing activity toward diverse HCV genotypes and protects against heterologous HCV challenge in a small animal model. The mAb panel will be useful for the design and development of vaccine candidates to elicit broadly neutralizing antibodies to HCV.

  11. Field Study and Energy-Plus Benchmarks for Energy Saver Homes having Different Envelope Designs

    SciTech Connect

    Shrestha, Som S; Childs, Kenneth W; Stannard, Eric E

    2012-01-01

    An alliance to maximize energy efficiency and cost-effective residential construction (ZEBRAlliance) built and field tested four homes that are 50 percent more energy efficient than a code compliant home. The homes are unoccupied for the duration of a two-year field study, thereby eliminating the confounding issue of occupancy habits. All homes have about the same consistent and scheduled internal load. Each home showcases a unique envelope strategy: 1) structural insulated panel (SIP), 2) optimal value wall framing (OVF), 3) advanced framing featuring the benefits of insulations mixed with phase change materials (PCM), and 4) an exterior insulation and finish system (EIFS). All homes have different weather resistive barriers (WRBs) and/or air barriers to limit air and moisture infiltration. Three homes provide space conditioning and water heating via a ground loop heat exchanger, while the fourth home uses a high efficiency air-to-air heat pump and heat pump water heater. Field performance and results of EnergyPlus V7.0 benchmarks were made for roof and attics as compared to cathedral design and for wall heat flows to validate models. The moisture content of the wall sheathing is shown to prove the protecting effectiveness of WRBs. Temperature distributions through insulations in the wall and ceiling with and without PCMs are described to characterize the performance of the PCM building envelopes.

  12. Energy Impacts of Envelope Tightening and Mechanical Ventilation for the U.S. Residential Sector

    SciTech Connect

    Logue, J. M.; Sherman, M. H.; Walker, I. S.; Singer, B. C.

    2013-01-01

    Effective residential envelope air sealing reduces infiltration and associated energy costs for thermal conditioning, yet often creates a need for mechanical ventilation to protect indoor air quality. This study estimated the potential energy savings of implementing airtightness improvements or absolute standards along with mechanical ventilation throughout the U.S. housing stock. We used a physics-based modeling framework to simulate the impact of envelope tightening, providing mechanical ventilation as needed. There are 113 million homes in the US. We calculated the change in energy demand for each home in a nationally representative sample of 50,000 virtual homes developed from the 2009 Residential Energy Consumption Survey. Ventilation was provided as required by 2010 and proposed 2013 versions of ASHRAE Standard 62.2. Ensuring that all current homes comply with 62.2-2010 would increase residential site energy demand by 0.07 quads (0.07 exajoules (EJ)) annually. Improving airtightness of all homes at current average retrofit performance levels would decrease demand by 0.7 quads (0.74 EJ) annually and upgrading all homes to be as airtight as the top 10% of similar homes would double the savings, leading to roughly $22 billion in annual savings in energy bills. We also analyzed the potential benefits of bringing the entire stock to airtightness specifications of IECC 2012, Canada's R2000, and Passive House standards.

  13. Role of Human Immunodeficiency Virus Type 1 Envelope Structure in the Induction of Broadly Neutralizing Antibodies

    PubMed Central

    Benjelloun, F.; Lawrence, P.; Verrier, B.; Genin, C.

    2012-01-01

    Very soon after the discovery of neutralizing antibodies (NAbs) toward human immunodeficiency virus type 1 (HIV-1) infection, it became apparent that characterization of these NAbs would be an important step in finding a cure for or a vaccine to eradicate HIV-1. Since the initial description of broadly cross-clade NAbs naturally produced in HIV-1 patients, numerous studies have described new viral targets for these antibodies. More recently, studies concerning new groups of patients able to control their viremia, such as long-term nonprogressors (LTNPs) or elite controllers, have described the generation of numerous envelope-targeted NAbs. Recent studies have marked a new stage in research on NAbs with the description of antibodies obtained from a worldwide screening of HIV-positive patients. These studies have permitted the discovery of NAb families with great potential for both neutralization and neutralization breadth, such as PG, PGT, CH, and highly active agonistic anti-CD4 binding site antibodies (HAADs), of which VRC01 and its variants are members. These antibodies are able to neutralize more than 80% of circulating strains without any autoreactivity and can be rapidly integrated into clinical trials in order to test their protective potential. In this review, we will focus on new insights into HIV-1 envelope structure and their implications for the generation of potent NAbs. PMID:23015715

  14. 10 CFR 434.516 - Building exterior envelope.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... default assumptions for computing the Design Energy Consumption. The solar absorptivity of opaque elements... 10 Energy 3 2012-01-01 2012-01-01 false Building exterior envelope. 434.516 Section 434.516 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CODE FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH...

  15. 10 CFR 434.516 - Building exterior envelope.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... default assumptions for computing the Design Energy Consumption. The solar absorptivity of opaque elements... 10 Energy 3 2011-01-01 2011-01-01 false Building exterior envelope. 434.516 Section 434.516 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CODE FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH...

  16. 10 CFR 434.516 - Building exterior envelope.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... default assumptions for computing the Design Energy Consumption. The solar absorptivity of opaque elements... 10 Energy 3 2013-01-01 2013-01-01 false Building exterior envelope. 434.516 Section 434.516 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY CODE FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH...

  17. Use and interpretation of climate envelope models: a practical guide

    USGS Publications Warehouse

    Watling, James I.; Brandt, Laura A.; Mazzotti, Frank J.; Romañach, Stephanie S.

    2013-01-01

    This guidebook is intended to provide a practical overview of climate envelope modeling for conservation professionals and natural resource managers. The material is intended for people with little background or experience in climate envelope modeling who want to better understand and interpret models developed by others and the results generated by such models, or want to do some modeling themselves. This is not an exhaustive review of climate envelope modeling, but rather a brief introduction to some key concepts in the discipline. Readers interested in a more in-depth treatment of much of the material presented here are referred to an excellent book, Mapping Species Distributions: Spatial Inference and Prediction by Janet Franklin. Also, a recent review (Araújo & Peterson 2012) provides an excellent, though more technical, discussion of many of the issues dealt with here. Here we treat selected topics from a practical perspective, using minimal jargon to explain and illustrate some of the many issues that one has to be aware of when using climate envelope models. When we do introduce specialized terminology in the guidebook, we bold the term when it is first used; a glossary of these terms is included at the back of the guidebook.

  18. Preparation of privatization samples for envelopes `A` and `C`

    SciTech Connect

    Winters, W.I., Westinghouse Hanford

    1996-07-17

    As part of the TWRS Privatization process, the DOE has committed to provide each of the two contractors who submitted successful bids with ten 125 mL samples of Hanford tank waste meeting chemical and radionuclide criteria specified as Waste Envelope A, B, and C. This test plan describes how the samples will be prepared before shipment.

  19. 10 CFR 434.402 - Building envelope assemblies and materials.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... MULTI-FAMILY HIGH RISE RESIDENTIAL BUILDINGS Building Design Requirements-Electric Systems and Equipment... Information. 402.1.1Material Properties. Information on thermal properties, building envelope system... RS-10 (incorporated by reference, see § 434.701). 402.2.1Air Barrier System. A barrier...

  20. 10 CFR 434.402 - Building envelope assemblies and materials.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... MULTI-FAMILY HIGH RISE RESIDENTIAL BUILDINGS Building Design Requirements-Electric Systems and Equipment... Information. 402.1.1Material Properties. Information on thermal properties, building envelope system... RS-10 (incorporated by reference, see § 434.701). 402.2.1Air Barrier System. A barrier...

  1. New tools for the analysis and design of building envelopes

    SciTech Connect

    Papamichael, K.; Winkelmann, F.C.; Buhl, W.F.; Chauvet, H.

    1994-08-01

    We describe the integrated development of PowerDOE, a new version of the DOE-2 building energy analysis program, and the Building Design Advisor (BDA), a multimedia-based design tool that assists building designers with the concurrent consideration of multiple design solutions with respect to multiple design criteria. PowerDOE has a windows-based Graphical User Interface (GUI) that makes it easier to use than DOE-2, while retaining DOE-2`s calculation power and accuracy. BDA, with a similar GUI, is designed to link to multiple analytical models and databases. In its first release it is linked to PowerDOE and a Daylighting Analysis Module, as well as to a Case Studies Database and a Schematic Graphic Editor. These allow building designers to set performance goals and address key building envelope parameters from the initial, schematic phases of building design to the detailed specification of building components and systems required by PowerDOE. The consideration of the thermal performance of building envelopes through PowerDOE and BDA is integrated with non-thermal envelope performance aspects, such as daylighting, as well as with the performance of non-envelope building components and systems, such as electric lighting and HVAC. Future versions of BDA will support links to CAD and electronic product catalogs, as well as provide context-dependent design advice to improve performance.

  2. 14 CFR 29.1517 - Limiting height-speed envelope.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Operating Limitations and Information Operating Limitations § 29.1517 Limiting height-speed envelope. For Category A rotorcraft, if a range of... following power failure, the range of heights and its variation with forward speed must be...

  3. 14 CFR 29.1517 - Limiting height-speed envelope.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Operating Limitations and Information Operating Limitations § 29.1517 Limiting height-speed envelope. For Category A rotorcraft, if a range of... following power failure, the range of heights and its variation with forward speed must be...

  4. 14 CFR 29.1517 - Limiting height-speed envelope.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Operating Limitations and Information Operating Limitations § 29.1517 Limiting height-speed envelope. For Category A rotorcraft, if a range of... following power failure, the range of heights and its variation with forward speed must be...

  5. 14 CFR 29.1517 - Limiting height-speed envelope.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Operating Limitations and Information Operating Limitations § 29.1517 Limiting height-speed envelope. For Category A rotorcraft, if a range of... following power failure, the range of heights and its variation with forward speed must be...

  6. Neural coding of sound envelope in reverberant environments.

    PubMed

    Slama, Michaël C C; Delgutte, Bertrand

    2015-03-11

    Speech reception depends critically on temporal modulations in the amplitude envelope of the speech signal. Reverberation encountered in everyday environments can substantially attenuate these modulations. To assess the effect of reverberation on the neural coding of amplitude envelope, we recorded from single units in the inferior colliculus (IC) of unanesthetized rabbit using sinusoidally amplitude modulated (AM) broadband noise stimuli presented in simulated anechoic and reverberant environments. Although reverberation degraded both rate and temporal coding of AM in IC neurons, in most neurons, the degradation in temporal coding was smaller than the AM attenuation in the stimulus. This compensation could largely be accounted for by the compressive shape of the modulation input-output function (MIOF), which describes the nonlinear transformation of modulation depth from acoustic stimuli into neural responses. Additionally, in a subset of neurons, the temporal coding of AM was better for reverberant stimuli than for anechoic stimuli having the same modulation depth at the ear. Using hybrid anechoic stimuli that selectively possess certain properties of reverberant sounds, we show that this reverberant advantage is not caused by envelope distortion, static interaural decorrelation, or spectral coloration. Overall, our results suggest that the auditory system may possess dual mechanisms that make the coding of amplitude envelope relatively robust in reverberation: one general mechanism operating for all stimuli with small modulation depths, and another mechanism dependent on very specific properties of reverberant stimuli, possibly the periodic fluctuations in interaural correlation at the modulation frequency.

  7. Modification of selected South Carolina bridge-scour envelope curves

    USGS Publications Warehouse

    Benedict, Stephen T.; Caldwell, Andral W.

    2012-01-01

    Historic scour was investigated at 231 bridges in the Piedmont and Coastal Plain physiographic provinces of South Carolina by the U.S. Geological Survey in cooperation with the South Carolina Department of Transportation. These investigations led to the development of field-derived envelope curves that provided supplementary tools to assess the potential for scour at bridges in South Carolina for selected scour components that included clear-water abutment, contraction, and pier scour, and live-bed pier and contraction scour. The envelope curves consist of a single curve with one explanatory variable encompassing all of the measured field data for the respective scour components. In the current investigation, the clear-water abutment-scour and live-bed contraction-scour envelope curves were modified to include a family of curves that utilized two explanatory variables, providing a means to further refine the assessment of scour potential for those specific scour components. The modified envelope curves and guidance for their application are presented in this report.

  8. Spectral Envelopes and Additive + Residual Analysis/Synthesis

    NASA Astrophysics Data System (ADS)

    Rodet, Xavier; Schwarz, Diemo

    The subject of this chapter is the estimation, representation, modification, and use of spectral envelopes in the context of sinusoidal-additive-plus-residual analysis/synthesis. A spectral envelope is an amplitude-vs-frequency function, which may be obtained from the envelope of a short-time spectrum (Rodet et al., 1987; Schwarz, 1998). [Precise definitions of such an envelope and short-time spectrum (STS) are given in Section 2.] The additive-plus-residual analysis/synthesis method is based on a representation of signals in terms of a sum of time-varying sinusoids and of a non-sinusoidal residual signal [e.g., see Serra (1989), Laroche et al. (1993), McAulay and Quatieri (1995), and Ding and Qian (1997)]. Many musical sound signals may be described as a combination of a nearly periodic waveform and colored noise. The nearly periodic part of the signal can be viewed as a sum of sinusoidal components, called partials, with time-varying frequency and amplitude. Such sinusoidal components are easily observed on a spectral analysis display (Fig. 5.1) as obtained, for instance, from a discrete Fourier transform.

  9. Modeling of heat and mass transfer in lateritic building envelopes

    NASA Astrophysics Data System (ADS)

    Meukam, Pierre; Noumowe, Albert

    2005-12-01

    The aim of the present work is to investigate the behavior of building envelopes made of local lateritic soil bricks subjected to different climatic conditions. The building envelopes studied in this work consist of lateritic soil bricks with incorporation of natural pozzolan or sawdust in order to obtain small thermal conductivity and low-density materials. In order to describe coupled heat and moisture transfer in wet porous materials, the coupled equations were solved by the introduction of diffusion coefficients. A numerical model HMtrans, developed for prediction of heat and moisture transfer in multi-layered building components, was used to simulate the temperature, water content and relative humidity profiles within the building envelopes. The results allow the prediction of the duration of the exposed building walls to the local weather conditions. They show that the durability of building envelopes made of lateritic soil bricks with incorporation of natural pozzolan or sawdust is not strongly affected by the climatic conditions in tropical and equatorial areas.

  10. Nuclear envelope reformation and chromosome decondensation are dissociable events.

    PubMed

    Ghosh, S; Paweletz, N; Armas-Portela, R

    1988-06-01

    Cells treated with 2,4-dinitrophenol, a metabolic inhibitor, show a strong retardation of anaphase movement. At the ultrastructural level these cells reveal nuclear envelope reformation without concurrent decondensation of the chromosomes which indicates that these are possibly two dissociable late mitotic events.

  11. COMMON ENVELOPE EVOLUTION LEADING TO SUPERNOVAE WITH DENSE INTERACTION

    SciTech Connect

    Chevalier, Roger A.

    2012-06-10

    A variety of supernova events, including Type IIn supernovae and ultraluminous supernovae, appear to have lost up to solar masses of their envelopes in tens to hundreds of years leading up to the explosion. In order to explain the close timing of the mass loss and supernova events, we explore the possibility that the mass loss is driven by common envelope evolution of a compact object (neutron star or black hole) in the envelope of a massive star and the supernova is triggered by the inspiral of the compact object to the central core of the companion star. The expected rate of such events is smaller than the observed rate of Type IIn supernovae but the rates may agree within the uncertainties. The mass loss velocity is related to the escape velocity from the common envelope system and is comparable to the observed velocity of hundreds of kilometers per second in Type IIn events. The mass loss is expected to be denser near the equatorial plane of the binary system and there is good evidence that the circumstellar media in Type IIn supernovae are asymmetric. Some of these supernova types show evidence for energies in excess of the canonical 10{sup 51} erg, which might be the result of explosions from rapid accretion onto a compact object through a disk.

  12. Effects of masker envelope coherence on intensity discrimination

    PubMed Central

    Buss, Emily; Hall, Joseph W.

    2009-01-01

    Masked detection threshold for a pure tone signal depends on the coherence of masker envelope fluctuation across frequency, with lower thresholds for coherent fluctuation under some conditions. The benefit of coherent masker modulation is larger for detection than for suprathreshold tasks, such as pure tone intensity discrimination [Hall, J. W. and Grose, J. H. (1995). J. Acoust. Soc. Am. 98, 847–852]. In the present study, sensitivity to increments in signal intensity was measured for a 1000-Hz signal, either a tone or a 20-Hz-wide narrowband noise. In one set of conditions the masker was one or more bands of noise, each 20 Hz wide, and in another set of conditions the masker was a single 1620-Hz-wide band of Gaussian noise or noise multiplied by the envelope of a 20-Hz bandpass noise. Coherent masker envelope fluctuation improved detection thresholds in all conditions. Intensity discrimination for a tonal standard in comodulated noise was elevated for standard levels near detection threshold and improved with increasing signal-to-noise ratio, whereas performance was uniformly poor across level for the noise standard. Results are most consistent with the interpretation that the reduced benefit of coherent masker modulation in suprathreshold intensity discrimination is due to the disruptive effects of envelope fluctuation. PMID:19894827

  13. Arms Race between Enveloped Viruses and the Host ERAD Machinery

    PubMed Central

    Frabutt, Dylan A.; Zheng, Yong-Hui

    2016-01-01

    Enveloped viruses represent a significant category of pathogens that cause serious diseases in animals. These viruses express envelope glycoproteins that are singularly important during the infection of host cells by mediating fusion between the viral envelope and host cell membranes. Despite low homology at protein levels, three classes of viral fusion proteins have, as of yet, been identified based on structural similarities. Their incorporation into viral particles is dependent upon their proper sub-cellular localization after being expressed and folded properly in the endoplasmic reticulum (ER). However, viral protein expression can cause stress in the ER, and host cells respond to alleviate the ER stress in the form of the unfolded protein response (UPR); the effects of which have been observed to potentiate or inhibit viral infection. One important arm of UPR is to elevate the capacity of the ER-associated protein degradation (ERAD) pathway, which is comprised of host quality control machinery that ensures proper protein folding. In this review, we provide relevant details regarding viral envelope glycoproteins, UPR, ERAD, and their interactions in host cells. PMID:27657106

  14. Infalling Envelopes and Pre-Main Sequence Disks

    NASA Technical Reports Server (NTRS)

    Hartmann, Lee W.

    1997-01-01

    The goal of this project is to understand the observed infrared emission of young stellar objects, and explore the implications of this emission for the evolution of dusty envelopes and circumstellar disks. We are using sophisticated radiative transfer methods to compare models with observations, thereby making critical tests of the standard picture of low-mass star formation.

  15. Envelopment technique and topographic overlays in bite mark analysis

    PubMed Central

    Djeapragassam, Parimala; Daniel, Mariappan Jonathan; Srinivasan, Subramanian Vasudevan; Ramadoss, Koliyan; Jimsha, Vannathan Kumaran

    2015-01-01

    Aims and Objectives: The aims and objectives of our study were to compare four sequential overlays generated using the envelopment technique and to evaluate inter- and intraoperator reliability of the overlays obtained by the envelopment technique. Materials and Methods: Dental stone models were prepared from impressions made from healthy individuals; photographs were taken and computer-assisted overlays were generated. The models were then enveloped in a different-color dental stone. After this, four sequential cuts were made at a thickness of 1mm each. Each sectional cut was photographed and overlays were generated. Thus, 125 overlays were generated and compared. Results: The scoring was done based on matching accuracy and the data were analyzed. The Kruskal-Wallis one-way analysis of variance (ANOVA) test was used to compare four sequential overlays and Spearman's rank correlation tests were used to evaluate the inter- and intraoperator reliability of the overlays obtained by the envelopment technique. Conclusion: Through our study, we conclude that the third and fourth cuts were the best among the four cuts and inter- and intraoperator reliability were found to be statistically significant at 5% level that is 95% confidence interval (P < 0.05). PMID:26816458

  16. Causes and consequences of nuclear envelope alterations in tumour progression.

    PubMed

    Bell, Emily S; Lammerding, Jan

    2016-11-01

    Morphological changes in the size and shape of the nucleus are highly prevalent in cancer, but the underlying molecular mechanisms and the functional relevance remain poorly understood. Nuclear envelope proteins, which can modulate nuclear shape and organization, have emerged as key components in a variety of signalling pathways long implicated in tumourigenesis and metastasis. The expression of nuclear envelope proteins is altered in many cancers, and changes in levels of nuclear envelope proteins lamins A and C are associated with poor prognosis in multiple human cancers. In this review we highlight the role of the nuclear envelope in different processes important for tumour initiation and cancer progression, with a focus on lamins A and C. Lamin A/C controls many cellular processes with key roles in cancer, including cell invasion, stemness, genomic stability, signal transduction, transcriptional regulation, and resistance to mechanical stress. In addition, we discuss potential mechanisms mediating the changes in lamin levels observed in many cancers. A better understanding of cause-and-effect relationships between lamin expression and tumour progression could reveal important mechanisms for coordinated regulation of oncogenic processes, and indicate therapeutic vulnerabilities that could be exploited for improved patient outcome.

  17. The Two Envelope Problem: There Is No Conundrum

    ERIC Educational Resources Information Center

    Mitchell, S. L.; O'Brien, S. B. G.

    2014-01-01

    We consider the famous two envelope conundrum and show, in a very simple way, that there is no conundrum. Our discussion is supported by numerical simulations. We use the problem to raise the issue of disputes in mathematics, rarely touched upon in mathematics education. We suggest that it is worthwhile to expose students of mathematics to such…

  18. Edge envelope equation for a ballistically focused neutralized ion beam

    SciTech Connect

    Lemons, D.S.; Thode, L.E.

    1980-11-01

    An envelope equation for a cold ion beam with overall charge and current neutralization provided by a coflowing electron gas obeying an adiabatic equation of state is derived. The derivation assumes the beam evolves self-similarly with the ion at the edge of a uniform density ion profile. Numerical and approximate analytical solutions are calculated.

  19. Dynamic Flight Envelope Assessment with Flight Safety Applications

    NASA Astrophysics Data System (ADS)

    Pandita, Rohit

    Aircraft have a manufacturer prescribed operating flight envelope for safe operation, exceeding these limits can result in unrecoverable departures or even structural failure. Numerous commercial aircraft accidents in the past have been attributed to loss-of-control (LOC) resulting from exceeding the safe operating flight envelope. Hence, real-time knowledge of the safe operating flight envelope is essential for safe flight operation, a problem known as dynamic flight envelope assessment. This dissertation explores dynamic flight envelope assessment from a control theoretic perspective. Two notions of the flight envelope, namely, the reachable sets and the region-of-attraction analysis are investigated. The NASA generic transport model (GTM) aircraft dynamics is used as an application problem. Linear and nonlinear techniques for flight envelope assessment are formulated in the linear matrix inequality (LMI) and sum-of-squares (SOS) framework, respectively. LMI and SOS problems are computationally tractable convex optimization problems for which many semi-definite programming solvers are available. This thesis also investigated fault detection and isolation strategies. Commercial jet transport aircrafts make extensive use of active controls. Faults or failures in the flight control system (FCS) elements like sensors or control effectors can lead to catastrophic failure. Model-based fault detection and isolation (FDI) filters can provide analytical redundancy by reliably detecting such faults in the system. Practical application of model-based FDI filters is limited so far due to poor performance, false alarms and missed detection arising out of uncertain dynamics of the aircraft, effect of nonlinearities in the system and the influence of closed-loop controllers. An application of closed-loop metrics to assess worst case FDI filter performance in the presence of a controller and uncertain dynamics is presented. Longitudinal GTM dynamics are considered. An Hinfinity

  20. Differentiation and ultrastructure of oncospheral and uterine envelopes in the nematotaeniid cestode, Nematotaenia dispar (Goeze, 1782).

    PubMed

    Swiderski, Z; Tkach, V

    1997-09-01

    The oncospheral envelopes of infective eggs in Nematotaenia dispar include the outer envelope with 2 sublayers, the inner envelope with a fibrillar embryophore and 2 cytoplasmic sublayers, and the oncospheral membrane. They differentiate from 3 primary embryonic envelopes, capsule, outer and inner envelope. The uterine envelopes are formed around the early embryos by processes of uterine epithelial cells, which surround the capsules. They degenerate rapidly in later stages; however, some structural components of the uterine envelopes were still visible in gravid proglottids as flattened perikarya with pyknotic, lobate nuclei, residual membranous structures and cellular debris situated usually between eggs. The following ultrastructural features of oncospheral envelopes differentiation appear to be characteristic for N. dispar: (1) lack of the outer capsule or shell in the fully mature eggs; (2) bi-layered structure of the outer envelope and tri-layered structure of the inner envelope; (3) absence of hook region membrane resulting probably from its early disintegration; (4) presence of small vesicles or "pits" incorporated into the inner envelope plasma membrane; (5) presence of densely packed microtubules in the external layer of the inner envelope; (6) changes in number of mitochondria and free ribosomes in the external and internal layers of inner envelope during egg maturation; and (7) probable "passage" of mitochondria and free ribosomes through the embryophoral pores in the developing eggs.

  1. Antigenic Properties of the HIV Envelope on Virions in Solution

    PubMed Central

    Mengistu, Meron; Lewis, George K.; Lakowicz, Joseph R.

    2014-01-01

    The structural flexibility found in human immunodeficiency virus (HIV) envelope glycoproteins creates a complex relationship between antigenicity and sensitivity to antiviral antibodies. The study of this issue in the context of viral particles is particularly problematic as conventional virus capture approaches can perturb antigenicity profiles. Here, we employed a unique analytical system based on fluorescence correlation spectroscopy (FCS), which measures antibody-virion binding with all reactants continuously in solution. Panels of nine anti-envelope monoclonal antibodies (MAbs) and five virus types were used to connect antibody binding profiles with neutralizing activities. Anti-gp120 MAbs against the 2G12 or b12 epitope, which marks functional envelope structures, neutralized viruses expressing CCR5-tropic envelopes and exhibited efficient virion binding in solution. MAbs against CD4-induced (CD4i) epitopes considered hidden on functional envelope structures poorly bound these viruses and were not neutralizing. Anti-gp41 MAb 2F5 was neutralizing despite limited virion binding. Similar antigenicity patterns occurred on CXCR4-tropic viruses, except that anti-CD4i MAbs 17b and 19e were neutralizing despite little or no virion binding. Notably, anti-gp120 MAb PG9 and anti-gp41 MAb F240 bound to both CCR5-tropic and CXCR4-tropic viruses without exerting neutralizing activity. Differences in the virus production system altered the binding efficiencies of some antibodies but did not enhance antigenicity of aberrant gp120 structures. Of all viruses tested, only JRFL pseudoviruses showed a direct relationship between MAb binding efficiency and neutralizing potency. Collectively, these data indicate that the antigenic profiles of free HIV particles generally favor the exposure of functional over aberrant gp120 structures. However, the efficiency of virion-antibody interactions in solution inconsistently predicts neutralizing activity in vitro. PMID:24284318

  2. Metal cladding envelope problems, retrofit solutions, and quality control investigations

    NASA Astrophysics Data System (ADS)

    Colantonio, Antonio

    1992-04-01

    This paper deals with a case study of a building envelope retrofit of an insulated sheet steel and corrugated metal clad building. The building in discussion is a satellite testing facility which requires specific clean room conditions with controlled interior temperature (22 degree(s)C +/- 1 degree(s)C) and high relative humidity conditions (45% +/- 3%) to facilitate satellite testing programs. Preliminary mechanical system inspections indicated substantial increase in air intake to make up for air leakage losses. An infrared inspection along with an approximate air leakage test of the building envelope was requested by the client to determine the magnitude of the building envelope problem. This investigation concluded that significant air leakage was present throughout the building envelope and that existing mechanical systems did not have sufficient capacity to pressurize the building and negate wind and stack effect. Exfiltration particularly through openings on the top sections of the building were causing interior moisture to saturate wall insulation and render it ineffective. Concern for rusting of metal components was indicated. The subsequent envelope analysis discovered a number of typical metal building details that led to poor air tightness and wall insulation ineffectiveness. These were correlated to infrared investigation data. The retrofit solutions produced for this building not only apply to this building but to other similar building types. Further investigations indicated that air leakage and mechanical system performance were significant problems with buildings using metal cladding systems comparable to this building. Quality control before, during and after construction was identified as an important function of the architectural commissioning of the retrofit work and infrared investigations were used to verify locations of air leakage and insulation effectiveness.

  3. FILAMENTARY STAR FORMATION: OBSERVING THE EVOLUTION TOWARD FLATTENED ENVELOPES

    SciTech Connect

    Lee, Katherine; Looney, Leslie; Johnstone, Doug; Tobin, John E-mail: lwl@illinois.edu E-mail: jtobin@nrao.edu

    2012-12-20

    Filamentary structures are ubiquitous from large-scale molecular clouds (a few parsecs) to small-scale circumstellar envelopes around Class 0 sources ({approx}1000 AU to {approx}0.1 pc). In particular, recent observations with the Herschel Space Observatory emphasize the importance of large-scale filaments (a few parsecs) and star formation. The small-scale flattened envelopes around Class 0 sources are reminiscent of the large-scale filaments. We propose an observationally derived scenario for filamentary star formation that describes the evolution of filaments as part of the process for formation of cores and circumstellar envelopes. If such a scenario is correct, small-scale filamentary structures (0.1 pc in length) with higher densities embedded in starless cores should exist, although to date almost all the interferometers have failed to observe such structures. We perform synthetic observations of filaments at the prestellar stage by modeling the known Class 0 flattened envelope in L1157 using both the Combined Array for Research in Millimeter-wave Astronomy (CARMA) and the Atacama Large Millimeter/Submillimeter Array (ALMA). We show that with reasonable estimates for the column density through the flattened envelope, the CARMA D array at 3 mm wavelengths is not able to detect such filamentary structure, so previous studies would not have detected them. However, the substructures may be detected with the CARMA D+E array at 3 mm and the CARMA E array at 1 mm as a result of more appropriate resolution and sensitivity. ALMA is also capable of detecting the substructures and showing the structures in detail compared to the CARMA results with its unprecedented sensitivity. Such detection will confirm the new proposed paradigm of non-spherical star formation.

  4. The Consonant-Weighted Envelope Difference Index (cEDI): A Proposed Technique for Quantifying Envelope Distortion

    ERIC Educational Resources Information Center

    Hoover, Eric C.; Souza, Pamela E.; Gallun, Frederick J.

    2012-01-01

    Purpose: The benefits of amplitude compression in hearing aids may be limited by distortion resulting from rapid gain adjustment. To evaluate this, it is convenient to quantify distortion by using a metric that is sensitive to the changes in the processed signal that decrease consonant recognition, such as the Envelope Difference Index (EDI;…

  5. Hfq reduces envelope stress by controlling expression of envelope-localized proteins and protein complexes in enteropathogenic Escherichia coli.

    PubMed

    Vogt, Stefanie L; Raivio, Tracy L

    2014-05-01

    Gram-negative bacteria possess several envelope stress responses that detect and respond to damage to this critical cellular compartment. The σ(E) envelope stress response senses the misfolding of outer membrane proteins (OMPs), while the Cpx two-component system is believed to detect the misfolding of periplasmic and inner membrane proteins. Recent studies in several Gram-negative organisms found that deletion of hfq, encoding a small RNA chaperone protein, activates the σ(E) envelope stress response. In this study, we assessed the effects of deleting hfq upon activity of the σ(E) and Cpx responses in non-pathogenic and enteropathogenic (EPEC) strains of Escherichia coli. We found that the σ(E) response was activated in Δhfq mutants of all E. coli strains tested, resulting from the misregulation of OMPs. The Cpx response was activated by loss of hfq in EPEC, but not in E. coli K-12. Cpx pathway activation resulted in part from overexpression of the bundle-forming pilus (BFP) in EPEC Δhfq. We found that Hfq repressed expression of the BFP via PerA, a master regulator of virulence in EPEC. This study shows that Hfq has a more extensive role in regulating the expression of envelope proteins and horizontally acquired virulence genes in E. coli than previously recognized.

  6. Function of nuclear membrane proteins in shaping the nuclear envelope integrity during closed mitosis.

    PubMed

    Yang, Hui-Ju; Iwamoto, Masaaki; Hiraoka, Yasushi; Haraguchi, Tokuko

    2017-04-08

    The nuclear envelope (NE) not only protects the genome from being directly accessed by detrimental agents but also regulates genome organization. Breaches in NE integrity threaten genome stability and impede cellular function. Nonetheless, the NE constantly remodels, and NE integrity is endangered in dividing or differentiating cells. Specifically, in unicellular eukaryotes undergoing closed mitosis, the NE expands instead of breaking down during chromosome segregation. The newly assembling nuclear pore complexes (NPCs) penetrate the existing NE in interphase. A peculiar example of NE remodeling during nuclear differentiation in Tetrahymena involves formation of the redundant NE and clustered NPCs. Even under these conditions, the NE remains intact. Many recent studies on unicellular organisms have revealed that nuclear membrane proteins, such as LEM-domain proteins, play a role in maintaining NE integrity. This review summarizes and discusses how nuclear membrane proteins participate in NE integrity.

  7. Aerothermal Performance Envelopes for Hypersonic Small Radius Unswept Leading Edges and Nosetips

    NASA Technical Reports Server (NTRS)

    Kolodziej, Paul; Rasky, Daniel J. (Technical Monitor)

    1995-01-01

    Small radius leading edges and nosetips were utilized to minimize wave drag in early hypersonic vehicle concepts until further analysis demonstrated that extreme aerothermodynamic heating would cause severe ablation or blunting of the available thermal protection system materials. Recent studies indicate that diboride composite materials are shape stable under extreme aerothermodynamic heating at ultra high temperatures. Aerothermal performance envelopes for sharp components made from these materials are presented in this work to demonstrate the effects of convective blocking, surface catalycity, surface emissivity, and rarefied flow effects on steady state operation at altitudes from sea level to 90 km. These components are capable of steady state operation at velocities up to 7.9 km/s at altitudes near 90 km.

  8. Flight Envelope Information-Augmented Display for Enhanced Pilot Situation Awareness

    NASA Technical Reports Server (NTRS)

    Ackerman, Kasey A.; Seefeldt, Benjamin D.; Xargay, Enric; Talleur, Donald A.; Carbonari, Ronald S.; Kirlik, Alex; Hovakimyan, Naira; Trujillo, Anna C.; Belcastro, Christine M.; Gregory, Irene M.

    2015-01-01

    This paper presents an interface system display which is conceived to improve pilot situation awareness with respect to a flight envelope protection system developed for a mid-sized transport aircraft. The new display is designed to complement existing cockpit displays, and to augment them with information that relates to both aircraft state and the control automation itself. In particular, the proposed display provides cues about the state of automation directly in terms of pilot control actions, in addition to flight parameters. The paper also describes a forthcoming evaluation test plan that is intended to validate the developed interface by assessing the relevance of the displayed information, as well as the adequacy of the display layout.

  9. Immunogenicity of a purified fragment of 17D yellow fever envelope protein.

    PubMed

    Brandriss, M W; Schlesinger, J J; Walsh, E E

    1990-06-01

    Information on the immunogenic properties of purified flavivirus proteins may be useful in the development of recombinant or synthetic peptide vaccines. Using a monoclonal antibody, an attempt was made to purify the envelope (E) protein of 17D yellow fever virus (17D YF) by affinity chromatography. The purified material could not be identified as intact E protein but it did bear antigenic determinants of E as determined by selective reactivity with anti-E monoclonal antibodies. Rabbits immunized with this material produced antibodies that neutralized 17D YF and dengue-2 viruses in comparable titers, indicating that cross-reactive antigenic determinants were preserved. Immunization of mice resulted in protection against intracerebral challenge with 17D YF.

  10. Ultrastructural study of the egg wall surrounding the developing miracidia of the digenean Prosotocus confusus (Looss, 1894) (Plagiorchiida: Pleurogenidae), with the description of a unique cocoon-like envelope.

    PubMed

    Świderski, Zdzisław; Miquel, Jordi; Torres, Jordi; Conn, David Bruce

    2015-01-01

    Helminth eggs play a critical role in movement of the parasite from definitive to intermediate host. Eggs of the pleurogenid digenean trematode Prosotocus confusus (Looss, 1894), a parasite of naturally infected frogs Pelophylax lessonae (Amphibia: Ranidae) in Europe, are described here for the first time. Particular emphasis is placed on the ultrastructure on the egg wall and on the detailed description of a unique cocoon-like envelope. Each embryonating egg is composed of an early embryo surrounded by a four-layered egg wall: (1) an outer, anucleate layer external to the eggshell, which forms a thick cocoon; (2) the operculate eggshell; (3) not fully formed, a differentiating outer embryonic envelope containing large nuclei of macromeres; and (4) situated below, an undifferentiated layer of the future inner embryonic envelope containing mesomere nuclei. Layers enveloping the egg apparently play an important role in the protection, metabolism, and storage of nutritive reserves for the developing miracidium. The outer anucleate layer, or cocoon, is situated externally to the eggshell and composed of an electron-lucent substance with numerous electron-dense islands attached to its peripheral membrane. A cocoon envelope such as this has never been seen in previous TEM studies of the eggs of parasitic platyhelminths, with the exception of another pleurogenid Brandesia turgida. The origin, formation, functional ultrastructure, and chemical composition of this peculiar layer remain enigmatic, although its function appears to be protective. The thick, electron-dense eggshell resembles that of other trematodes, exhibiting a characteristic fissure zone around the operculum. Numerous lysosome-like structures observed in some eggs may be involved in the autolysis of both the embryonic envelopes (particularly the early degeneration of macromere nuclei of the outer envelope, characteristic for this species) and in the disintegration of several early micromeres. The inner

  11. A rat model of human immunodeficiency virus 1 encephalopathy using envelope glycoprotein gp120 expression delivered by SV40 vectors.

    PubMed

    Louboutin, Jean-Pierre; Agrawal, Lokesh; Reyes, Beverly A S; Van Bockstaele, Elisabeth J; Strayer, David S

    2009-05-01

    Human immunodeficiency virus 1 (HIV-1) encephalopathy is thought to result in part from the toxicity of HIV-1 envelope glycoprotein gp120 for neurons. Experimental systems for studying the effects of gp120 and other HIV proteins on the brain have been limited to the acute effects of recombinant proteins in vitro or in vivo in simian immunodeficiency virus-infected monkeys. We describe an experimental rodent model of ongoing gp120-induced neurotoxicity in which HIV-1 envelope is expressed in the brain using an SV40-derived gene delivery vector, SV(gp120). When it is inoculated stereotaxically into the rat caudate putamen, SV(gp120) caused a partly hemorrhagic lesion in which neuron and other cell apoptosis continues for at least 12 weeks. Human immunodeficiency virus gp120 is expressed throughout this time, and some apoptotic cells are gp120 positive. Malondialdehyde and 4-hydroxynonenal assays indicated that there was lipid peroxidation in these lesions. Prior administration of recombinant SV40 vectors carrying antioxidant enzymes, copper/ zinc superoxide dismutase or glutathione peroxidase, was protective against SV(gp120)-induced oxidative injury and apoptosis. Thus, in vivo inoculation of SV(gp120) into the rat caudate putamen causes ongoing oxidative stress and apoptosis in neurons and may therefore represent a useful animal model for studying the pathogenesis and treatment of HIV-1 envelope-related brain damage.

  12. Habitat classification modeling with incomplete data: Pushing the habitat envelope

    USGS Publications Warehouse

    Zarnetske, P.L.; Edwards, T.C.; Moisen, G.G.

    2007-01-01

    Habitat classification models (HCMs) are invaluable tools for species conservation, land-use planning, reserve design, and metapopulation assessments, particularly at broad spatial scales. However, species occurrence data are often lacking and typically limited to presence points at broad scales. This lack of absence data precludes the use of many statistical techniques for HCMs. One option is to generate pseudo-absence points so that the many available statistical modeling tools can be used. Traditional techniques generate pseudoabsence points at random across broadly defined species ranges, often failing to include biological knowledge concerning the species-habitat relationship. We incorporated biological knowledge of the species-habitat relationship into pseudo-absence points by creating habitat envelopes that constrain the region from which points were randomly selected. We define a habitat envelope as an ecological representation of a species, or species feature's (e.g., nest) observed distribution (i.e., realized niche) based on a single attribute, or the spatial intersection of multiple attributes. We created HCMs for Northern Goshawk (Accipiter gentilis atricapillus) nest habitat during the breeding season across Utah forests with extant nest presence points and ecologically based pseudo-absence points using logistic regression. Predictor variables were derived from 30-m USDA Landfire and 250-m Forest Inventory and Analysis (FIA) map products. These habitat-envelope-based models were then compared to null envelope models which use traditional practices for generating pseudo-absences. Models were assessed for fit and predictive capability using metrics such as kappa, thresholdindependent receiver operating characteristic (ROC) plots, adjusted deviance (Dadj2), and cross-validation, and were also assessed for ecological relevance. For all cases, habitat envelope-based models outperformed null envelope models and were more ecologically relevant, suggesting

  13. Cloning and characterization of functional subtype A HIV-1 envelope variants transmitted through breastfeeding.

    PubMed

    Rainwater, Stephanie M J; Wu, Xueling; Nduati, Ruth; Nedellec, Rebecca; Mosier, Donald; John-Stewart, Grace; Mbori-Ngacha, Dorothy; Overbaugh, Julie

    2007-03-01

    Previous studies of HIV-1 variants transmitted from mother-to-infant have focused primarily on computational analyses of partial envelope gene sequences, rather than analyses of functional envelope variants. There are very few examples of well-characterized functional envelope clones from mother-infant pairs, especially from envelope variants representing the most prevalent subtypes worldwide. To address this, we amplified the envelope variants present in 4 mother-infant transmission pairs, all of whom were infected with subtype A and three of whom presumably transmitted HIV-1 during the breastfeeding period. Functional envelope clones were constructed, either encoding full-length envelope sequences from the mother and baby or by making chimeric envelope clones in a common backbone sequence. The infant envelope sequences were genetically homogeneous compared to the maternal viruses, and pseudoviruses bearing these envelopes all used CCR5 as a coreceptor. The infant viruses were generally resistant to neutralization by maternal antibodies present near the time of transmission. There were no notable differences in sensitivity of the mother and infant envelope variants to neutralization by heterologous plasma or monoclonal antibodies 2G12 and b12, or to inhibition by sCD4, PSC-RANTES or TAK779. This collection of viral envelopes, which can be used for making pseudotyped viruses, may be useful for examining the efficacy of interventions to block mother-infant transmission, including sera from vaccine candidates, purified antibodies under consideration for passive immunization and viral entry inhibitors.

  14. Maximum Torque and Momentum Envelopes for Reaction Wheel Arrays

    NASA Technical Reports Server (NTRS)

    Markley, F. Landis; Reynolds, Reid G.; Liu, Frank X.; Lebsock, Kenneth L.

    2009-01-01

    Spacecraft reaction wheel maneuvers are limited by the maximum torque and/or angular momentum that the wheels can provide. For an n-wheel configuration, the torque or momentum envelope can be obtained by projecting the n-dimensional hypercube, representing the domain boundary of individual wheel torques or momenta, into three dimensional space via the 3xn matrix of wheel axes. In this paper, the properties of the projected hypercube are discussed, and algorithms are proposed for determining this maximal torque or momentum envelope for general wheel configurations. Practical strategies for distributing a prescribed torque or momentum among the n wheels are presented, with special emphasis on configurations of four, five, and six wheels.

  15. Computing the Envelope for Stepwise Constant Resource Allocations

    NASA Technical Reports Server (NTRS)

    Muscettola, Nicola; Clancy, Daniel (Technical Monitor)

    2001-01-01

    Estimating tight resource level is a fundamental problem in the construction of flexible plans with resource utilization. In this paper we describe an efficient algorithm that builds a resource envelope, the tightest possible such bound. The algorithm is based on transforming the temporal network of resource consuming and producing events into a flow network with noises equal to the events and edges equal to the necessary predecessor links between events. The incremental solution of a staged maximum flow problem on the network is then used to compute the time of occurrence and the height of each step of the resource envelope profile. The staged algorithm has the same computational complexity of solving a maximum flow problem on the entire flow network. This makes this method computationally feasible for use in the inner loop of search-based scheduling algorithms.

  16. Balmer line profiles for infalling T Tauri envelopes

    NASA Technical Reports Server (NTRS)

    Calvet, Nuria; Hartmann, Lee

    1992-01-01

    The possibility that the Balmer emission lines of T Tauri stars arise in infalling envelopes rather than winds is considered. Line profiles for the upper Balmer lines are presented for models with cone geometry, intended to simulate the basic features of magnetospheric accretion from a circumstellar disk. An escape probability treatment is used to determine line source functions in nonspherically symmetric geometry. Thermalization effects are found to produce nearly symmetric H-alpha line profiles at the same time the higher Balmer series lines exhibit inverse P Cygni profiles. The infall models produce centrally peaked emission line wings, in good agreement with observations of many T Tauri stars. It is suggested that the Balmer emission of many T Tauri stars may be produced in an infalling envelope, with blue shifted absorption contributed by an overlying wind. Some of the observed narrow absorption components with small blueshifts may also arise in the accretion column.

  17. Full-Envelope Launch Abort System Performance Analysis Methodology

    NASA Technical Reports Server (NTRS)

    Aubuchon, Vanessa V.

    2014-01-01

    The implementation of a new dispersion methodology is described, which dis-perses abort initiation altitude or time along with all other Launch Abort System (LAS) parameters during Monte Carlo simulations. In contrast, the standard methodology assumes that an abort initiation condition is held constant (e.g., aborts initiated at altitude for Mach 1, altitude for maximum dynamic pressure, etc.) while dispersing other LAS parameters. The standard method results in large gaps in performance information due to the discrete nature of initiation conditions, while the full-envelope dispersion method provides a significantly more comprehensive assessment of LAS abort performance for the full launch vehicle ascent flight envelope and identifies performance "pinch-points" that may occur at flight conditions outside of those contained in the discrete set. The new method has significantly increased the fidelity of LAS abort simulations and confidence in the results.

  18. Prediction of Spacecraft Vibration using Acceleration and Force Envelopes

    NASA Technical Reports Server (NTRS)

    Gordon, Scott; Kaufman, Daniel; Kern, Dennis; Scharton, Terry

    2009-01-01

    The base forces in the GLAST X- and Z-axis sine vibration tests were similar to those derived using generic inputs (from users guide and handbook), but the base forces in the sine test were generally greater than the flight data. Basedrive analyses using envelopes of flight acceleration data provided more accurate predictions of the base force than generic inputs, and as expected, using envelopes of both the flight acceleration and force provided even more accurate predictions The GLAST spacecraft interface accelerations and forces measured during the MECO transient were relatively low in the 60 to 150 Hz regime. One may expect the flight forces measured at the base of various spacecraft to be more dependent on the mass, frequencies, etc. of the spacecraft than are the corresponding interface acceleration data, which may depend more on the launch vehicle configuration.

  19. Virulence Properties of the Legionella Pneumophila Cell Envelope

    PubMed Central

    Shevchuk, Olga; Jäger, Jens; Steinert, Michael

    2011-01-01

    The bacterial envelope plays a crucial role in the pathogenesis of infectious diseases. In this review, we summarize the current knowledge of the structure and molecular composition of the Legionella pneumophila cell envelope. We describe lipopolysaccharides biosynthesis and the biological activities of membrane and periplasmic proteins and discuss their decisive functions during the pathogen–host interaction. In addition to adherence, invasion, and intracellular survival of L. pneumophila, special emphasis is laid on iron acquisition, detoxification, key elicitors of the immune response and the diverse functions of outer membrane vesicles. The critical analysis of the literature reveals that the dynamics and phenotypic plasticity of the Legionella cell surface during the different metabolic stages require more attention in the future. PMID:21747794

  20. Analytical and numerical predictions of dendritic grain envelopes

    SciTech Connect

    Gandin, C.A.; Rappaz, M.; Schaefer, R.J.

    1996-08-01

    An analytical model is developed for the prediction of the shape of dendritic grain envelopes during solidification of a metallic alloy in a Bridgman configuration (i.e., constant thermal gradient and cooling rate). The assumptions built into the model allow a direct comparison of the results with those obtained from a previously developed cellular automation-finite element (CAFE) model. After this comparison, the CAFE model is applied to the study of the extension of a single grain into an open region of liquid after passing a re-entrant corner. The simulation results are compared with experimental observations made on a directionally solidified succinonitrile-acetone alloy. Good agreement is found for the shape of the grain envelopes when varying the orientation of the primary dendrites with respect to the thermal gradient direction, the velocity of the isotherms or the thermal gradient.

  1. Subdwarf B stars from the common envelope ejection channel

    NASA Astrophysics Data System (ADS)

    Xiong, H.; Chen, X.; Podsiadlowski, Ph.; Li, Y.; Han, Z.

    2017-02-01

    Context. Subdwarf B stars (sdB) are important to stellar evolutionary theory and asteroseismology, and they are crucial to our understanding of the structure and evolution of the Galaxy. According to the canonical binary scenario, the majority of sdBs are produced from low-mass stars with degenerate cores where helium is ignited in a way of flashes. Owing to numerical difficulties, the models of produced sdBs are generally constructed from more massive stars with non-degenerate cores. This leaves several uncertainties on the exact characteristics of sdB stars. Aims: The purpose of this paper is to study the characteristics of sdBs produced from the common envelope (CE) ejection channel. Methods: We used the stellar evolution code Modules for Experiments in Stellar Astrophysics (MESA), which can resolve flashes during stellar evolution. To mimic the CE ejection process, we first evolved a single star to a position near the tip of the red giant branch, then artificially removed its envelope with a very high mass-loss rate until the envelope began to shrink. Finally, we followed the evolution of the remnant until it became a helium or a carbon-oxygen white dwarf. Results: The sdB stars produced from the CE ejection channel appear to form two distinct groups on the effective temperature-gravity diagram. One group, referred to as the flash-mixing sdBs, almost has no H-rich envelope and crowds at the hottest temperature end of the extreme horizontal branch (EHB), while the other group, called the canonical sdBs, has significant H-rich envelope and is spread throughout the entire canonical EHB region. The key factor for the dichotomy of the sdB properties is the development of convection during the first helium flash, that is, that the convection region penetrates the H-rich envelope in the case of the flash-mixing sdBs, but fails to do this in the case of the canonical sdBs. Conclusions: The dichotomy of the sdB properties from the CE ejection channel is intrinsic and

  2. Time dependent wave envelope finite difference analysis of sound propagation

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.

    1984-01-01

    A transient finite difference wave envelope formulation is presented for sound propagation, without steady flow. Before the finite difference equations are formulated, the governing wave equation is first transformed to a form whose solution tends not to oscillate along the propagation direction. This transformation reduces the required number of grid points by an order of magnitude. Physically, the transformed pressure represents the amplitude of the conventional sound wave. The derivation for the wave envelope transient wave equation and appropriate boundary conditions are presented as well as the difference equations and stability requirements. To illustrate the method, example solutions are presented for sound propagation in a straight hard wall duct and in a two dimensional straight soft wall duct. The numerical results are in good agreement with exact analytical results.

  3. Influence of Building Envelope Thermal Mass on Heating Design Temperature

    NASA Astrophysics Data System (ADS)

    Gaujena, B.; Borodinecs, A.; Zemitis, J.; Prozuments, A.

    2015-11-01

    The stability of indoor air parameters is a very important factor, essential for such institutions as museums, schools and hospitals. Nowadays the use of renewable energy for space heating became one of the top priorities in modern building design. The active and passive solar energy as well as heat pumps are widely used nowadays. However, such technologies have a limitation in cold climates and often are not able to cover maximal heating loads. This paper is devoted to analysis of influence of building envelope's properties and outdoor air parameters on indoor air thermodynamic parameters stability in winter time. It presents analysis of thermal mass impact on building energy performance and indoor air parameter stability in cold climate. The results show that the thermal mass of building envelope is able to cover extreme winter temperatures as well as in case of emergency heat supply break.

  4. Expanded Content Envelope For The Model 9977 Packaging

    SciTech Connect

    Abramczyk, G. A.; Loftin, B. M.; Nathan, S. J.; Bellamy, J. S.

    2013-07-30

    An Addendum was written to the Model 9977 Safety Analysis Report for Packaging adding a new content consisting of DOE-STD-3013 stabilized plutonium dioxide materials to the authorized Model 9977 contents. The new Plutonium Oxide Content (PuO{sub 2}) Envelope will support the Department of Energy shipment of materials between Los Alamos National Laboratory and Savannah River Site facilities. The new content extended the current content envelope boundaries for radioactive material mass and for decay heat load and required a revision to the 9977 Certificate of Compliance prior to shipment. The Addendum documented how the new contents/configurations do not compromise the safety basis presented in the 9977 SARP Revision 2. The changes from the certified package baseline and the changes to the package required to safely transport this material is discussed.

  5. Computing the Envelope for Stepwise-Constant Resource Allocations

    NASA Technical Reports Server (NTRS)

    Muscettola, Nicola; Clancy, Daniel (Technical Monitor)

    2002-01-01

    Computing tight resource-level bounds is a fundamental problem in the construction of flexible plans with resource utilization. In this paper we describe an efficient algorithm that builds a resource envelope, the tightest possible such bound. The algorithm is based on transforming the temporal network of resource consuming and producing events into a flow network with nodes equal to the events and edges equal to the necessary predecessor links between events. A staged maximum flow problem on the network is then used to compute the time of occurrence and the height of each step of the resource envelope profile. Each stage has the same computational complexity of solving a maximum flow problem on the entire flow network. This makes this method computationally feasible and promising for use in the inner loop of flexible-time scheduling algorithms.

  6. 1612 MHz OH maser emission from axisymmetric circumstellar envelopes - Miras

    NASA Technical Reports Server (NTRS)

    Collison, Alan J.; Fix, John D.

    1992-01-01

    Radiative transfer calculations are performed using a modified form of the Sobolev approximation to determine the inversion of the 1612 MHz line of OH in axisymmetric circumstellar envelopes around Miras. The mass loss is assumed to be occurring in the form of a smooth wind. Line profiles and maps are presented for three models of varying degrees of asymmetry and for various orientations of the envelopes. It is concluded that the axisymmetric models can reproduce many of the features of observed profiles and maps which both the standard, spherically symmetric model and the discrete emission model cannot easily explain. The model profiles reproduce all of the general features seen in the line profiles of real sources.

  7. Virus strategies for passing the nuclear envelope barrier

    PubMed Central

    Kobiler, Oren; Drayman, Nir; Butin-Israeli, Veronika; Oppenheim, Ariella

    2012-01-01

    Viruses that replicate in the nucleus need to pass the nuclear envelope barrier during infection. Research in recent years indicates that the nuclear envelope is a major hurdle for many viruses. This review describes strategies to overcome this obstacle developed by seven virus families: herpesviridae, adenoviridae, orthomyxoviridae, lentiviruses (which are part of retroviridae), Hepadnaviridae, parvoviridae and polyomaviridae. Most viruses use the canonical nuclear pore complex (NPC) in order to get their genome into the nucleus. Viral capsids that are larger than the nuclear pore disassemble before or during passing through the NPC, thus allowing genome nuclear entry. Surprisingly, increasing evidence suggest that parvoviruses and polyomaviruses may bypass the nuclear pore by trafficking directly through the nuclear membrane. Additional studies are required for better understanding these processes. Since nuclear entry emerges as the limiting step in infection for many viruses, it may serve as an ideal target for antiviral drug development. PMID:22929056

  8. Case Study of Envelope Sealing in Existing Multiunit Structures

    SciTech Connect

    Dentz, Jordan; Conlin, Francis; Podorson, David

    2012-10-01

    This report describes envelope air sealing that was included in the retrofit of a 244 unit low-rise multifamily housing complex in Durham, N.C. On average, total leakage was reduced by nearly half, from 19.7 ACH50 to 9.4 ACH50. Important air leakage locations identified included plumbing and electrical penetrations, dropped ceilings/soffits, windows, ducts and wall-to-floor intersections. Specifications and a pictorial guide were developed for contractors performing the work.

  9. A Comparison of PSD Enveloping Methods for Nonstationary Vibration

    NASA Technical Reports Server (NTRS)

    Irvine, Tom

    2015-01-01

    There is a need to derive a power spectral density (PSD) envelope for nonstationary acceleration time histories, including launch vehicle data, so that components can be designed and tested accordingly. This paper presents the results of the three methods for an actual flight accelerometer record. Guidelines are given for the application of each method to nonstationary data. The method can be extended to other scenarios, including transportation vibration.

  10. The envelope of ballistic trajectories and elliptic orbits

    NASA Astrophysics Data System (ADS)

    Butikov, Eugene I.

    2015-11-01

    Simple geometric derivations are given for the shape of the "safety domain" boundary for the family of Keplerian orbits of equal energy in a central gravitational field and for projectile trajectories in a uniform field. Examples of practical uses of the envelope of the family of orbits are discussed and illustrated by computer simulations. This material is appropriate for physics teachers and undergraduate students studying classical mechanics and orbital motions.

  11. Envelope solitons of acoustic plate modes and surface waves.

    PubMed

    Mayer, Andreas P; Kovalev, Alexander S

    2003-06-01

    The problem of the existence of evelope solitons in elastic plates and at solid surfaces covered by an elastic film is revisited with special attention paid to nonlinear long-wave short-wave interactions. Using asymptotic expansions and multiple scales, conditions for the existence of envelope solitons are established and it is shown how their parameters can be expressed in terms of the elastic moduli and mass densities of the materials involved. In addition to homogeneous plates, weak periodic modulation of the plate's material parameters are also considered. In the case of wave propagation in an elastic plate, modulations of weakly nonlinear carrier waves are governed by a coupled system of partial differential equations consisting of evolution equations for the complex amplitude of the carrier wave (the nonlinear Schrödinger equation for envelope solitons and the Mills-Trullinger equations for gap solitons), and the wave equation for long-wavelength acoustic plate modes. In contrast to this situation, envelope solitons of surface acoustic waves in a layered structure are normally described by the nonlinear Schrödinger equation alone. However, at higher orders of the carrier wave amplitude, the envelope soliton is found to be accompanied by a quasistatic long-wavelength strain field, which may be localized at the surface with penetration depth into the substrate of the order of the inverse amplitude or which may radiate energy into the bulk. A new set of modulation equations is derived for the resonant case of the carrier wave's group velocity being equal to the phase velocity of long-wavelength Rayleigh waves of the uncoated substrate.

  12. Expert Meeting Report: Advanced Envelope Research for Factory Built Housing

    SciTech Connect

    Levy, E.; Mullens, M.; Tompos, E.; Kessler, B.; Rath, P.

    2012-04-01

    This report provides information about the expert meeting on advanced envelope research for factory built housing, hosted by the ARIES Collaborative on October 11, 2011, in Phoenix, Arizona. The goals of this meeting were to provide a comprehensive solution to the use of three previously selected advanced alternatives for factory-built wall construction, assess each option focusing on major issues relating to viability and commercial potential, and determine additional steps are required to reach this potential.

  13. Expert Meeting Report: Advanced Envelope Research for Factory Built Housing

    SciTech Connect

    Levy, E.; Mullens, M.; Tompos, E.; Kessler, B.; Rath, P.

    2012-04-01

    This report provides information about the Building America expert meeting on advanced envelope research for factory built housing, hosted by the ARIES Collaborative on October 11, 2011, in Phoenix, Arizona. The goals of this meeting were to provide a comprehensive solution to the use of three previously selected advanced alternatives for factory-built wall construction, assess each option focusing on major issues relating to viability and commercial potential, and determine additional steps are required to reach this potential.

  14. Structure of the cell envelope of Halobacterium halobium

    PubMed Central

    1976-01-01

    The structure of the isolated cell envelope of Halobacterium halobium is studied by X-ray diffraction, electron microscopy, and biochemical analysis. The envelope consists of the cell membrane and two layers of protein outside. The outer layer of protein shows a regular arrangement of the protein or glycoprotein particles and is therefore identified as the cell wall. Just outside the cell membrane is a 20 A-thick layer of protein. It is a third structure in the envelope, the function of which may be distinct from that of the cell membrane and the cell wall. This inner layer of protein is separated from the outer protein layer by a 65 A-wide space which has an electron density very close to that of the suspending medium, and which can be etched after freeze-fracture. The space is tentatively identified as the periplasmic space. At NaCl concentrations below 2.0 M, both protein layers of the envelope disintegrate. Gel filtration and analytical ultracentrifugation of the soluble components from the two protein layers reveal two major bands of protein with apparent mol wt of approximately 16,000 and 21,000. At the same time, the cell membrane stays essentially intact as long as the Mg++ concentration is kept at treater than or equal to 20 mM. The cell membrane breaks into small fragments when treated with 0.1 M NaCl and EDTA, or with distilled water, and some soluble proteins, including flavins and cytochromes, are released. The cell membrane apparently has an asymmetric core of the lipid bilayer. PMID:977644

  15. Neutralizing antibodies decrease the envelope fluidity of HIV-1

    SciTech Connect

    Harada, Shinji Monde, Kazuaki; Tanaka, Yuetsu; Kimura, Tetsuya; Maeda, Yosuke; Yusa, Keisuke

    2008-01-05

    For successful penetration of HIV-1, the formation of a fusion pore may be required in order to accumulate critical numbers of fusion-activated gp41 with the help of fluidization of the plasma membrane and viral envelope. An increase in temperature to 40 {sup o}C after viral adsorption at 25 {sup o}C enhanced the infectivity by 1.4-fold. The enhanced infectivity was inhibited by an anti-CXCR4 peptide, T140, and anti-V3 monoclonal antibodies (0.5{beta} and 694/98-D) by post-attachment neutralization, but not by non-neutralizing antibodies (670-30D and 246-D) specific for the C5 of gp120 and cluster I of gp41, respectively. Anti-HLA-II and an anti-HTLV-I gp46 antibody, LAT27, neutralized the molecule-carrying HIV-1{sub C-2(MT-2)}. The anti-V3 antibodies suppressed the fluidity of the HIV-1{sub C-2} envelope, whereas the non-neutralizing antibodies did not. The anti-HLA-II antibody decreased the envelope fluidity of HIV-1{sub C-2(MT-2)}, but not that of HIV-1{sub C-2}. Therefore, fluidity suppression by these antibodies represents an important neutralization mechanism, in addition to inhibition of viral attachment.

  16. Detecting cell death with optical coherence tomography and envelope statistics

    NASA Astrophysics Data System (ADS)

    Farhat, Golnaz; Yang, Victor X. D.; Czarnota, Gregory J.; Kolios, Michael C.

    2011-02-01

    Currently no standard clinical or preclinical noninvasive method exists to monitor cell death based on morphological changes at the cellular level. In our past work we have demonstrated that quantitative high frequency ultrasound imaging can detect cell death in vitro and in vivo. In this study we apply quantitative methods previously used with high frequency ultrasound to optical coherence tomography (OCT) to detect cell death. The ultimate goal of this work is to use these methods for optically-based clinical and preclinical cancer treatment monitoring. Optical coherence tomography data were acquired from acute myeloid leukemia cells undergoing three modes of cell death. Significant increases in integrated backscatter were observed for cells undergoing apoptosis and mitotic arrest, while necrotic cells induced a decrease. These changes appear to be linked to structural changes observed in histology obtained from the cell samples. Signal envelope statistics were analyzed from fittings of the generalized gamma distribution to histograms of envelope intensities. The parameters from this distribution demonstrated sensitivities to morphological changes in the cell samples. These results indicate that OCT integrated backscatter and first order envelope statistics can be used to detect and potentially differentiate between modes of cell death in vitro.

  17. A nuclear-envelope bridge positions nuclei and moves chromosomes.

    PubMed

    Starr, Daniel A

    2009-03-01

    Positioning the nucleus is essential for the formation of polarized cells, pronuclear migration, cell division, cell migration and the organization of specialized syncytia such as mammalian skeletal muscles. Proteins that are required for nuclear positioning also function during chromosome movement and pairing in meiosis. Defects in these processes lead to human diseases including laminopathies. To properly position the nucleus or move chromosomes within the nucleus, the cell must specify the outer surface of the nucleus and transfer forces across both membranes of the nuclear envelope. KASH proteins are specifically recruited to the outer nuclear membrane by SUN proteins, which reside in the inner nuclear membrane. KASH and SUN proteins physically interact in the perinuclear space, forming a bridge across the two membranes of the nuclear envelope. The divergent N-terminal domains of KASH proteins extend from the surface of the nucleus into the cytoplasm and interact with the cytoskeleton, whereas the N-termini of SUN proteins extend into the nucleoplasm to interact with the lamina or chromatin. The bridge of SUN and KASH across the nuclear envelope functions to transfer forces that are generated in the cytoplasm into the nucleoplasm during nuclear migration, nuclear anchorage, centrosome attachment, intermediate-filament association and telomere clustering.

  18. Phosphatidylserine receptors: enhancers of enveloped virus entry and infection

    PubMed Central

    Moller-Tank, Sven; Maury, Wendy

    2014-01-01

    A variety of both RNA and DNA viruses envelop their capsids in a lipid bilayer. One of the more recently appreciated benefits this envelope is incorporation of phosphatidylserine (PtdSer). Surface exposure of PtdSer disguises viruses as apoptotic bodies; tricking cells into engulfing virions. This mechanism is termed apoptotic mimicry. Several PtdSer receptors have been identified to enhance virus entry and we have termed this group of proteins PtdSer-mediated virus entry enhancing receptors or PVEERs. These receptors enhance entry of a broad range of enveloped viruses. Internalization of virions by PVEERs provides a broad mechanism of entry with little investment by the virus itself and may allow some viruses to attach to cells, thereby making viral glycoprotein/cellular receptor interactions more probable. Alternatively, other viruses may rely entirely on PVEERs for internalization into endosomes. This review provides an overview of PtdSer receptors that serve as PVEERs and the biology behind virion/PVEER interaction. PMID:25277499

  19. Magnetic field amplification during the common envelope phase

    NASA Astrophysics Data System (ADS)

    Ohlmann, Sebastian T.; Röpke, Friedrich K.; Pakmor, Rüdiger; Springel, Volker; Müller, Ewald

    2016-10-01

    During the common envelope (CE) phase, a giant star in a binary system overflows its Roche lobe and unstable mass transfer leads to a spiral-in of the companion, resulting in a close binary system or in a merger of the stellar cores. Dynamo processes during the CE phase have been proposed as a mechanism to generate magnetic fields that are important for forming magnetic white dwarfs (MWDs) and for shaping planetary nebulae. Here, we present the first magnetohydrodynamics simulations of the dynamical spiral-in during a CE phase. We find that magnetic fields are strongly amplified in the accretion stream around the 1 M⊙ companion as it spirals into the envelope of a 2 M⊙ RG. This leads to field strengths of 10-100 kG throughout the envelope after 120 d. The magnetic field amplification is consistent with being driven by the magnetorotational instability. The field strengths reached in our simulation make the magnetic field interesting for diagnostic purposes, but they are dynamically irrelevant. They are also too small to explain the formation of the highest fields found in MWDs, but may be relevant for luminous red novae, and detecting magnetic fields in these events would support the scenario as proposed here.

  20. Metallicity dependence of turbulent pressure and macroturbulence in stellar envelopes

    NASA Astrophysics Data System (ADS)

    Grassitelli, L.; Fossati, L.; Langer, N.; Simón-Díaz, S.; Castro, N.; Sanyal, D.

    2016-08-01

    Macroturbulence, introduced as a fudge to reproduce the width and shape of stellar absorption lines, reflects gas motions in stellar atmospheres. While in cool stars, it is thought to be caused by convection zones immediately beneath the stellar surface, the origin of macroturbulence in hot stars is still under discussion. Recent works established a correlation between the turbulent-to-total pressure ratio inside the envelope of stellar models and the macroturbulent velocities observed in corresponding Galactic stars. To probe this connection further, we evaluated the turbulent pressure that arises in the envelope convective zones of stellar models in the mass range 1-125 M⊙ based on the mixing-length theory and computed for metallicities of the Large and Small Magellanic Cloud. We find that the turbulent pressure contributions in models with these metallicities located in the hot high-luminosity part of the Hertzsprung-Russel (HR) diagram is lower than in similar models with solar metallicity, whereas the turbulent pressure in low-metallicity models populating the cool part of the HR-diagram is not reduced. Based on our models, we find that the currently available observations of hot massive stars in the Magellanic Clouds appear to support a connection between macroturbulence and the turbulent pressure in stellar envelopes. Multidimensional simulations of sub-surface convection zones and a larger number of high-quality observations are necessary to test this idea more rigorously.

  1. Top-down protein identification using isotopic envelope fingerprinting.

    PubMed

    Xiao, Kaijie; Yu, Fan; Tian, Zhixin

    2017-01-30

    For top-down protein database search and identification from tandem mass spectra, our isotopic envelope fingerprinting search algorithm and ProteinGoggle search engine have demonstrated their strength of efficiently resolving heavily overlapping data as well separating non-ideal data with non-ideal isotopic envelopes from ideal ones with ideal isotopic envelopes. Here we report our updated ProteinGoggle 2.0 for intact protein database search with full-capacity. The indispensable updates include users' optional definition of dynamic post-translational modifications and static chemical labeling during database creation, comprehensive dissociation methods and ion series, as well as a Proteoform Score for each proteoform. ProteinGoggle has previously been benchmarked with both collision-based dissociation (CID, HCD) and electron-based dissociation (ETD) data of either intact proteins or intact proteomes. Here we report our further benchmarking of the new version of ProteinGoggle with publically available photon-based dissociation (UVPD) data (http://hdl.handle.net/2022/17316) of intact E. coli ribosomal proteins.

  2. Species-free species distribution models describe macroecological properties of protected area networks.

    PubMed

    Robinson, Jason L; Fordyce, James A

    2017-01-01

    Among the greatest challenges facing the conservation of plants and animal species in protected areas are threats from a rapidly changing climate. An altered climate creates both challenges and opportunities for improving the management of protected areas in networks. Increasingly, quantitative tools like species distribution modeling are used to assess the performance of protected areas and predict potential responses to changing climates for groups of species, within a predictive framework. At larger geographic domains and scales, protected area network units have spatial geoclimatic properties that can be described in the gap analysis typically used to measure or aggregate the geographic distributions of species (stacked species distribution models, or S-SDM). We extend the use of species distribution modeling techniques in order to model the climate envelope (or "footprint") of individual protected areas within a network of protected areas distributed across the 48 conterminous United States and managed by the US National Park System. In our approach we treat each protected area as the geographic range of a hypothetical endemic species, then use MaxEnt and 5 uncorrelated BioClim variables to model the geographic distribution of the climatic envelope associated with each protected area unit (modeling the geographic area of park units as the range of a species). We describe the individual and aggregated climate envelopes predicted by a large network of 163 protected areas and briefly illustrate how macroecological measures of geodiversity can be derived from our analysis of the landscape ecological context of protected areas. To estimate trajectories of change in the temporal distribution of climatic features within a protected area network, we projected the climate envelopes of protected areas in current conditions onto a dataset of predicted future climatic conditions. Our results suggest that the climate envelopes of some parks may be locally unique or have

  3. Species-free species distribution models describe macroecological properties of protected area networks

    PubMed Central

    Fordyce, James A.

    2017-01-01

    Among the greatest challenges facing the conservation of plants and animal species in protected areas are threats from a rapidly changing climate. An altered climate creates both challenges and opportunities for improving the management of protected areas in networks. Increasingly, quantitative tools like species distribution modeling are used to assess the performance of protected areas and predict potential responses to changing climates for groups of species, within a predictive framework. At larger geographic domains and scales, protected area network units have spatial geoclimatic properties that can be described in the gap analysis typically used to measure or aggregate the geographic distributions of species (stacked species distribution models, or S-SDM). We extend the use of species distribution modeling techniques in order to model the climate envelope (or “footprint”) of individual protected areas within a network of protected areas distributed across the 48 conterminous United States and managed by the US National Park System. In our approach we treat each protected area as the geographic range of a hypothetical endemic species, then use MaxEnt and 5 uncorrelated BioClim variables to model the geographic distribution of the climatic envelope associated with each protected area unit (modeling the geographic area of park units as the range of a species). We describe the individual and aggregated climate envelopes predicted by a large network of 163 protected areas and briefly illustrate how macroecological measures of geodiversity can be derived from our analysis of the landscape ecological context of protected areas. To estimate trajectories of change in the temporal distribution of climatic features within a protected area network, we projected the climate envelopes of protected areas in current conditions onto a dataset of predicted future climatic conditions. Our results suggest that the climate envelopes of some parks may be locally unique or

  4. Rapid Process to Generate Beam Envelopes for Optical System Analysis

    NASA Technical Reports Server (NTRS)

    Howard, Joseph; Seals, Lenward

    2012-01-01

    The task of evaluating obstructions in the optical throughput of an optical system requires the use of two disciplines, and hence, two models: optical models for the details of optical propagation, and mechanical models for determining the actual structure that exists in the optical system. Previous analysis methods for creating beam envelopes (or cones of light) for use in this obstruction analysis were found to be cumbersome to calculate and take significant time and resources to complete. A new process was developed that takes less time to complete beam envelope analysis, is more accurate and less dependent upon manual node tracking to create the beam envelopes, and eases the burden on the mechanical CAD (computer-aided design) designers to form the beam solids. This algorithm allows rapid generation of beam envelopes for optical system obstruction analysis. Ray trace information is taken from optical design software and used to generate CAD objects that represent the boundary of the beam envelopes for detailed analysis in mechanical CAD software. Matlab is used to call ray trace data from the optical model for all fields and entrance pupil points of interest. These are chosen to be the edge of each space, so that these rays produce the bounding volume for the beam. The x and y global coordinate data is collected on the surface planes of interest, typically an image of the field and entrance pupil internal of the optical system. This x and y coordinate data is then evaluated using a convex hull algorithm, which removes any internal points, which are unnecessary to produce the bounding volume of interest. At this point, tolerances can be applied to expand the size of either the field or aperture, depending on the allocations. Once this minimum set of coordinates on the pupil and field is obtained, a new set of rays is generated between the field plane and aperture plane (or vice-versa). These rays are then evaluated at planes between the aperture and field, at a

  5. Recombinant Hepatitis C Virus Envelope Glycoprotein Vaccine Elicits Antibodies Targeting Multiple Epitopes on the Envelope Glycoproteins Associated with Broad Cross-Neutralization

    PubMed Central

    Wong, Jason Alexander Ji-Xhin; Bhat, Rakesh; Hockman, Darren; Logan, Michael; Chen, Chao; Levin, Aviad; Frey, Sharon E.; Belshe, Robert B.; Tyrrell, D. Lorne

    2014-01-01

    ABSTRACT Although effective hepatitis C virus (HCV) antivirals are on the horizon, a global prophylactic vaccine for HCV remains elusive. The diversity of the virus is a major concern for vaccine development; there are 7 major genotypes of HCV found globally. Therefore, a successful vaccine will need to protect against HCV infection by all genotypes. Despite the diversity, many monoclonal antibodies (MAbs) with broadly cross-neutralizing activity have been described, suggesting the presence of conserved epitopes that can be targeted to prevent infection. Similarly, a vaccine comprising recombinant envelope glycoproteins (rE1E2) derived from the genotype 1a HCV-1 strain has been shown to be capable of eliciting cross-neutralizing antibodies in guinea pigs, chimpanzees, and healthy human volunteers. In order to investigate the basis for this cross-neutralization, epitope mapping of anti-E1E2 antibodies present within antisera from goats and humans immunized with HCV-1 rE1E2 was conducted through peptide mapping and competition studies with a panel of cross-neutralizing MAbs targeting various epitopes within E1E2. The immunized-goat antiserum was shown to compete with the binding of all MAbs tested (AP33, HC33.4, HC84.26, 1:7, AR3B, AR4A, AR5A, IGH526, and A4). Antisera showed the best competition against HC84.26 and AR3B and the weakest competition against AR4A. Furthermore, antisera from five immunized human vaccinees were shown to compete with five preselected MAbs (AP33, AR3B, AR4A, AR5A, and IGH526). These data show that immunization with HCV-1 rE1E2 elicits antibodies targeting multiple cross-neutralizing epitopes. Our results further support the use of such a vaccine antigen to induce cross-genotype neutralization. IMPORTANCE An effective prophylactic vaccine for HCV is needed for optimal control of the disease burden. The high diversity of HCV has posed a challenge for developing vaccines that elicit neutralizing antibodies for protection against infection

  6. 77 FR 67309 - Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-09

    ... Go-Around AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed special... Takeoff Thrust Control System (ATTCS) during go-around. The applicable airworthiness regulations do not... using any of the following methods: Federal eRegulations Portal: Go to http://www.regulations.gov/...

  7. Genetic control of T cell responsiveness to the Friend murine leukemia virus envelope antigen. Identification of class II loci of the H-2 as immune response genes

    PubMed Central

    1988-01-01

    T cells primed specifically for the envelope glycoprotein of Friend murine leukemia helper virus (F-MuLV) were prepared by immunizing mice with a recombinant vaccinia virus that expressed the entire env gene of F-MuLV. Significant proliferative responses of F-MuLV envelope- specific, H-2a/b T cells were observed when the T cells were stimulated with antigen-pulsed peritoneal exudate cells (PEC) having the b allele at the K, A beta, A alpha, and E beta loci of the H-2. On the other hand, PEC having only the kappa allele at these loci did not induce the envelope-specific T cell proliferation, even when the PEC had the b allele at the E alpha, S, or D loci. F-MuLV envelope-specific proliferation of H-2a/b T cells under the stimulation of antigen- pulsed, H-2a/b PEC was specifically blocked with anti-I-Ab and anti-I- Ek mAbs but not with anti-Kb, anti-Kk, or anti-I-Ak mAbs. Moreover, (B10.MBR x A/WySn)F1 mice that have the b allele only at the K locus but not in I-A subregion were nonresponders to the envelope glycoprotein, and the bm12 mutation at the A beta locus completely abolished the T cell responsiveness to this antigen. These results indicate that proliferative T cells recognize a limited number of epitopes on F-MuLV envelope protein in the context of I-Ab, hybrid I- Ak/b, and/or hybrid I-Ek/b class II MHC molecules but fail to recognize the same envelope protein in the context of I-Ak or I-Ek molecules. This influence of the H-2I region on T cell recognition of the envelope glycoprotein appeared to control in vivo induction of protective immunity against Friend virus complex after immunization with the vaccinia-F-MuLV env vaccine. Thus, these results provide, for the first time, direct evidence for Ir gene-controlled responder/nonresponder phenotypes influencing the immune response to a pathogenic virus of mice. PMID:3141552

  8. Evaluation of a novel microextraction technique for aqueous samples: porous membrane envelope filled with multiwalled carbon nanotubes coated with molecularly imprinted polymer.

    PubMed

    Tan, Feng; Deng, Minjie; Liu, Xue; Zhao, Hongxia; Li, Xiaona; Quan, Xie; Chen, Jingwen

    2011-03-01

    A novel microextraction technique based on membrane-protected multiwalled carbon nanotubes coated with molecularly imprinted polymer (MWCNTs-MIP) was developed. In this technique, MWCNTs-MIP were packed inside a polypropylene membrane envelope, which was then clamped onto a paper clip. For extraction, the packed membrane envelope was first impregnated with toluene and then placed in sample solutions. Target analytes in the solutions were first extracted into toluene in the membrane envelope, and were then extracted specifically onto the MWCNTs-MIP. After the extraction, target analytes were desorbed in methanol for liquid chromatography analysis. MWCNTs-MIP of prometryn were used as a model to demonstrate the feasibility of this novel microextraction technique. Factors affecting the extraction including organic solvent, stirring rate, extraction time, salt concentration, and pH were investigated. Under the optimized conditions, the limits of detection (a signal-to-noise ratio of 3) for the selected triazine herbicides were 0.08-0.38 μg/L. The prepared membrane envelope could be used at least 50 times. The developed method was used for the analysis of the triazines spiked in river water, wastewater, and liquid milk, with recoveries ranging from 79.3-97.4, 58.9-110.3 and 76.2-104.9%, respectively.

  9. Characterization of hepatitis C virus envelope glycoprotein complexes expressed by recombinant vaccinia viruses.

    PubMed Central

    Ralston, R; Thudium, K; Berger, K; Kuo, C; Gervase, B; Hall, J; Selby, M; Kuo, G; Houghton, M; Choo, Q L

    1993-01-01

    We constructed recombinant vaccinia virus vectors for expression of the structural region of hepatitis C virus (HCV). Infection of mammalian cells with a vector (vv/HCV1-906) encoding C-E1-E2-NS2 generated major protein species of 22 kDa (C), 33 to 35 kDa (E1), and 70 to 72 kDa (E2), as observed previously with other mammalian expression systems. The bulk of the E1 and E2 expressed by vv/HCV1-906 was found integrated into endoplasmic reticulum membranes as core-glycosylated species, suggesting that these E1 and E2 species represent intracellular forms of the HCV envelope proteins. HCV E1 and E2 formed E1-E2 complexes which were precipitated by either anti-E1 or anti-E2 serum and which sedimented at approximately 15 S on glycerol density gradients. No evidence of intermolecular disulfide bonding between E1 and E2 was detected. E1 and E2 were copurified to approximately 90% purity by mild detergent extraction followed by chromatography on Galanthus nivalus lectin-agarose and DEAE-Fractogel. Immunization of chimpanzees with purified E1-E2 generated high titers of anti-E1 and anti-E2 antibodies. Further studies, to be reported separately, demonstrated that purified E1-E2 complexes were recognized at high frequency by HCV+ human sera (D. Y. Chien, Q.-L. Choo, R. Ralston, R. Spaete, M. Tong, M. Houghton, and G. Kuo, Lancet, in press) and generated protective immunity in chimpanzees (Q.-L. Choo, G. Kuo, R. Ralston, A. Weiner, D. Chien, G. Van Nest, J. Han, K. Berger, K. Thudium, J. Kansopon, J. McFarland, A. Tabrizi, K. Ching, B. Mass, L. B. Cummins, E. Muchmore, and M. Houghton, submitted for publication), suggesting that these purified HCV envelope proteins display native HCV epitopes. Images PMID:8411378

  10. Modeling study of seated reach envelopes based on spherical harmonics with consideration of the difficulty ratings.

    PubMed

    Yu, Xiaozhi; Ren, Jindong; Zhang, Qian; Liu, Qun; Liu, Honghao

    2017-04-01

    Reach envelopes are very useful for the design and layout of controls. In building reach envelopes, one of the key problems is to represent the reach limits accurately and conveniently. Spherical harmonics are proved to be accurate and convenient method for fitting of the reach capability envelopes. However, extensive study are required on what components of spherical harmonics are needed in fitting the envelope surfaces. For applications in the vehicle industry, an inevitable issue is to construct reach limit surfaces with consideration of the seating positions of the drivers, and it is desirable to use population envelopes rather than individual envelopes. However, it is relatively inconvenient to acquire reach envelopes via a test considering the seating positions of the drivers. In addition, the acquired envelopes are usually unsuitable for use with other vehicle models because they are dependent on the current cab packaging parameters. Therefore, it is of great significance to construct reach envelopes for real vehicle conditions based on individual capability data considering seating positions. Moreover, traditional reach envelopes provide little information regarding the assessment of reach difficulty. The application of reach envelopes will improve design quality by providing difficulty-rating information about reach operations. In this paper, using the laboratory data of seated reach with consideration of the subjective difficulty ratings, the method of modeling reach envelopes is studied based on spherical harmonics. The surface fitting using spherical harmonics is conducted for circumstances both with and without seat adjustments. For use with adjustable seat, the seating position model is introduced to re-locate the test data. The surface fitting is conducted for both population and individual reach envelopes, as well as for boundary envelopes. Comparison of the envelopes of adjustable seat and the SAE J287 control reach envelope shows that the latter

  11. Effects of 2-acetylaminofluorene, dietary fats and antioxidants on nuclear envelope cytochrome P-450

    SciTech Connect

    Carubelli, R.; Graham, S.A.; Griffin, M.J.; McCay, P.B.

    1986-05-01

    The authors reported a marked loss of cytochrome P-450 in hepatic nuclear envelope (NE) but not in microsomes of male Sprague-Dawley rats fed a semipurified diet containing 0.05% w/w 2-acetylaminofluorene (AAF) for 3 weeks. This may reflect loss of NE capacity to detoxify AAF metabolites generated by microsomal P-450. They are now investigating if dietary effects such as progressive decrease in the incidence of AAF-induced tumors in rats fed high polyunsaturated fat diet (HPUF) vs. high saturated fat diet (HSF) vs. low fat diet (LF), and the anticarcinogenic activity of butylated hydroxytoluene (BHT; 0.3% w/w) correlate with preservation of NE P-450. Rats fed AAF HSF (25.6% w/w corn oil) showed marked loss of NE P-450 after 3 weeks; BHT protected against this loss. Rats fed AAF in HSF (25.6% w/w; 18 parts beef tallow + 2 parts corn oil), on the other hand, experienced a marked drop in NE P-450 after 9 weeks; BHT protected against this loss. Comparison of NE P-450 levels in control rats fed HPUF or HSF for 3 weeks with those of rats fed a semipurified diet with 10% fat or Purina chow (ca. 5% fat), support the prediction of an inverse correlation between the levels of dietary fat and the NE P-450 content. Studies on AAF and BHT effects using LF (2% w/w corn oil) are in progress.

  12. Protective Eyewear

    MedlinePlus

    ... Home > NEI for Kids > Protective Eyewear All About Vision About the Eye Ask a Scientist Video Series ... Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun ...

  13. DIVERGENCE, NOT DIVERSITY OF AN ATTENUATED EQUINE LENTIVIRUS VACCINE STRAIN CORRELATES WITH PROTECTION FROM DISEASE

    PubMed Central

    Craigo, Jodi K.; Barnes, Shannon; Cook, Sheila J.; Issel, Charles J.; Montelaro, Ronald C.

    2010-01-01

    We recently reported an attenuated EIAV vaccine study that directly examined the effect of lentiviral envelope sequence variation on vaccine efficacy. The study [1] demonstrated for the first time the failure of an ancestral vaccine to protect and revealed a significant, inverse, linear relationship between envelope divergence and protection from disease. In the current study we examine in detail the evolution of the attenuated vaccine strain utilized in this previous study. We demonstrate here that the attenuated strain progressively evolved during the six-month pre-challenge period and that the observed protection from disease was significantly associated with divergence from the original vaccine strain. PMID:20955830

  14. Behavioral/Systems/Cognitive Cortical Processing of Dynamic Sound Envelope Transitions

    PubMed Central

    Zhou, Yi; Wang, Xiaoqin

    2012-01-01

    Slow envelope fluctuations in the range of 2-20Hz provide important segmental cues for processing communication sounds. For a successful segmentation, a neural processor must capture envelope features associated with the rise and fall of signal energy, a process that is often challenged by the interference of background noise. This study investigated the neural representations of slowly varying envelopes in quiet and in background noise in the primary auditory cortex (A1) of awake marmoset monkeys. We characterized envelope features based on the local average and rate of change of sound level in envelope waveforms and identified envelope features to which neurons were selective by reverse correlation. Our results showed that envelope feature selectivity of A1 neurons was correlated with the degree of non-monotonicity in their static rate-level functions. Non-monotonic neurons exhibited greater feature selectivity than monotonic neurons in quiet and in background noise. The diverse envelope feature selectivity decreased spike-timing correlation among A1 neurons in response to the same envelope waveforms. As a result, the variability, but not the average, of the ensemble responses of A1 neurons represented more faithfully the dynamic transitions in low-frequency sound envelopes both in quiet and in background noise. PMID:21148013

  15. Predicted effects of sensorineural hearing loss on across-fiber envelope coding in the auditory nervea

    PubMed Central

    Swaminathan, Jayaganesh; Heinz, Michael G.

    2011-01-01

    Cross-channel envelope correlations are hypothesized to influence speech intelligibility, particularly in adverse conditions. Acoustic analyses suggest speech envelope correlations differ for syllabic and phonemic ranges of modulation frequency. The influence of cochlear filtering was examined here by predicting cross-channel envelope correlations in different speech modulation ranges for normal and impaired auditory-nerve (AN) responses. Neural cross-correlation coefficients quantified across-fiber envelope coding in syllabic (0–5 Hz), phonemic (5–64 Hz), and periodicity (64–300 Hz) modulation ranges. Spike trains were generated from a physiologically based AN model. Correlations were also computed using the model with selective hair-cell damage. Neural predictions revealed that envelope cross-correlation decreased with increased characteristic-frequency separation for all modulation ranges (with greater syllabic-envelope correlation than phonemic or periodicity). Syllabic envelope was highly correlated across many spectral channels, whereas phonemic and periodicity envelopes were correlated mainly between adjacent channels. Outer-hair-cell impairment increased the degree of cross-channel correlation for phonemic and periodicity ranges for speech in quiet and in noise, thereby reducing the number of independent neural information channels for envelope coding. In contrast, outer-hair-cell impairment was predicted to decrease cross-channel correlation for syllabic envelopes in noise, which may partially account for the reduced ability of hearing-impaired listeners to segregate speech in complex backgrounds. PMID:21682421

  16. AKNS eigenvalue spectrum for densely spaced envelope solitary waves

    NASA Astrophysics Data System (ADS)

    Slunyaev, Alexey; Starobor, Alexey

    2010-05-01

    The problem of the influence of one envelope soliton to the discrete eigenvalues of the associated scattering problem for the other envelope soliton, which is situated close to the first one, is discussed. Envelope solitons are exact solutions of the integrable nonlinear Schrödinger equation (NLS). Their generalizations (taking into account the background nonlinear waves [1-4] or strongly nonlinear effects [5, 6]) are possible candidates to rogue waves in the ocean. The envelope solitary waves could be in principle detected in the stochastic wave field by approaches based on the Inverse Scattering Technique in terms of ‘unstable modes' (see [1-3]), or envelope solitons [7-8]. However, densely spaced intense groups influence the spectrum of the associated scattering problem, so that the solitary trains cannot be considered alone. Here we solve the initial-value problem exactly for some simplified configurations of the wave field, representing two closely placed intense wave groups, within the frameworks of the NLS equation by virtue of the solution of the AKNS system [9]. We show that the analogues of the level splitting and the tunneling effects, known in quantum physics, exist in the context of the NLS equation, and thus may be observed in application to sea waves [10]. These effects make the detecting of single solitary wave groups surrounded by other nonlinear wave groups difficult. [1]. A.L. Islas, C.M. Schober (2005) Predicting rogue waves in random oceanic sea states. Phys. Fluids 17, 031701-1-4. [2]. A.R. Osborne, M. Onorato, M. Serio (2005) Nonlinear Fourier analysis of deep-water random surface waves: Theoretical formulation and and experimental observations of rogue waves. 14th Aha Huliko's Winter Workshop, Honolulu, Hawaii. [3]. C.M. Schober, A. Calini (2008) Rogue waves in higher order nonlinear Schrödinger models. In: Extreme Waves (Eds.: E. Pelinovsky & C. Kharif), Springer. [4]. N. Akhmediev, A. Ankiewicz, M. Taki (2009) Waves that appear from

  17. Sensitivity of envelope following responses to vowel polarity.

    PubMed

    Easwar, Vijayalakshmi; Beamish, Laura; Aiken, Steven; Choi, Jong Min; Scollie, Susan; Purcell, David

    2015-02-01

    Envelope following responses (EFRs) elicited by stimuli of opposite polarities are often averaged due to their insensitivity to polarity when elicited by amplitude modulated tones. A recent report illustrates that individuals exhibit varying degrees of polarity-sensitive differences in EFR amplitude when elicited by vowel stimuli (Aiken and Purcell, 2013). The aims of the current study were to evaluate the incidence and degree of polarity-sensitive differences in EFRs recorded in a large group of individuals, and to examine potential factors influencing the polarity-sensitive nature of EFRs. In Experiment I of the present study, we evaluated the incidence and degree of polarity-sensitive differences in EFR amplitude in a group of 39 participants. EFRs were elicited by opposite polarities of the vowel /ε/ in a natural /hVd/ context presented at 80 dB SPL. Nearly 30% of the participants with detectable responses (n = 24) showed a difference of greater than ∼39 nV in EFR response amplitude between the two polarities, that was unexplained by variations in noise estimates. In Experiment II, we evaluated the effect of vowel, frequency of harmonics and presence of the first harmonic (h1) on the polarity sensitivity of EFRs in 20 participants with normal hearing. For vowels /u/, /a/ and /i/, EFRs were elicited by two simultaneously presented carriers representing the first formant (resolved harmonics), and the second and higher formants (unresolved harmonics). Individual but simultaneous EFRs were elicited by the formant carriers by separating the fundamental frequency in the two carriers by 8 Hz. Vowels were presented as part of a naturally produced, but modified sequence /susaʃi/, at an overall level of 65 dB SPL. To evaluate the effect of h1 on polarity sensitivity of EFRs, EFRs were elicited by the same vowels without h1 in an identical sequence. A repeated measures analysis of variance indicated a significant effect of polarity on EFR amplitudes for the

  18. Core-Envelope Interior Models of the Outer Planets

    NASA Astrophysics Data System (ADS)

    Schubert, G.; Anderson, J. D.; Helled, R.

    2009-12-01

    The constraints on giant planet interior models with density discontinuities, for example, a core-envelope boundary, are more difficult to treat than a continuous density distribution that decreases monotonically and continuously from the center to the surface of the planet. We revise our previous interior calculations (Anderson, J. D., and G. Schubert, Saturn’s gravitational field, internal rotation, and interior structure, 2007, Science, 317, 1384-1387, doi: 101126/science.1144835, 2007), which solved a system of integro-differential equations to third order in the smallness parameter ω2a3/GM (ω is the angular velocity of the planet, a is the planet’s equatorial radius, G is the gravitational constant, and M is the planet’s mass), and introduce Clairaut’s differential equation for the flattening f, with appropriate boundary conditions at the planet’s surface and at its center. The calculations can be carried to second order in the smallness parameter by solving Darwin’s differential equation for k, a parameter that describes a second-order deviation from sphericity. In principle, the calculations can be extended to differential equations of arbitrary order in smallness. As with our earlier method, we apply this revised method to the outer planets with interiors comprising a compressible core, obeying a linear density distribution, and an envelope in which density vs. radius is described by a sixth degree polynomial. This method of gravity sounding, with cores and envelope polynomial density distributions, can yield insights into a class of possible cores that fit the boundary conditions, consisting of the measured even zonal gravitational harmonics, plus the measured size and total mass of the planet. We apply the method to the four outer planets.

  19. Empirical Constraints on Common Envelope Evolution in Wide Binaries

    NASA Astrophysics Data System (ADS)

    Geller, Aaron M.; Hurley, J. R.; Mathieu, R. D.

    2012-01-01

    If a giant star in a binary overfills its Roche lobe, the giant's convective envelope may respond by expanding faster than its Roche lobe, transferring mass on a dynamical time scale, and creating a common envelope (CE) that engulfs both stars. Orbital energy may then be transferred from the binary to the envelope, which can shrink the orbit and drive away the material, leaving behind a detached system containing the white dwarf core of the giant. Such a CE event is thought to be critical for explaining certain populations of exotic stars (e.g., cataclysmic variables). Yet the application of CE evolution to binary population synthesis and N-body or Monte Carlo star cluster models requires many poorly constrained assumptions, which may lead to unphysical evolutionary paths. In fact, we find that such fictitious systems are created regularly within our N-body models of the old (7 Gyr) open cluster NGC 188. Most notably, the model predicts a population of post-CE long-period ( 1000 days) circular solar-type main sequence - white dwarf binaries, that are not present in our observations of the true binaries in NGC 188, or any other solar-type binary population in the literature (in star clusters or in the field). The absence of such post-CE systems in real binary populations places important limits on parameters used in most models of CE evolution, and may suggest that more binaries undergo stable mass transfer than has previously been assumed. We discuss how various solutions to this problem would impact other observable stellar populations, including cataclysmic variables, symbiotic stars and blue stragglers.

  20. Biliary Secretion of Quasi-Enveloped Human Hepatitis A Virus

    PubMed Central

    Hirai-Yuki, Asuka; Hensley, Lucinda; Whitmire, Jason K.

    2016-01-01

    ABSTRACT Hepatitis A virus (HAV) is an unusual picornavirus that is released from cells cloaked in host-derived membranes. These quasi-enveloped virions (eHAV) are the only particle type circulating in blood during infection, whereas only nonenveloped virions are shed in feces. The reason for this is uncertain. Hepatocytes, the only cell type known to support HAV replication in vivo, are highly polarized epithelial cells with basolateral membranes facing onto hepatic (blood) sinusoids and apical membranes abutting biliary canaliculi from which bile is secreted to the gut. To assess whether eHAV and nonenveloped virus egress from cells via vectorially distinct pathways, we studied infected polarized cultures of Caco-2 and HepG2-N6 cells. Most (>99%) progeny virions were released apically from Caco-2 cells, whereas basolateral (64%) versus apical (36%) release was more balanced with HepG2-N6 cells. Both apically and basolaterally released virions were predominantly enveloped, with no suggestion of differential vectorial release of eHAV versus naked virions. Basolateral to apical transcytosis of either particle type was minimal (<0.02%/h) in HepG2-N6 cells, arguing against this as a mechanism for differences in membrane envelopment of serum versus fecal virus. High concentrations of human bile acids converted eHAV to nonenveloped virions, whereas virus present in bile from HAV-infected Ifnar1−/− Ifngr1−/− and Mavs−/− mice banded over a range of densities extending from that of eHAV to that of nonenveloped virions. We conclude that nonenveloped virions shed in feces are derived from eHAV released across the canalicular membrane and stripped of membranes by the detergent action of bile acids within the proximal biliary canaliculus. PMID:27923925

  1. A flattest constrained envelope approach for empirical mode decomposition.

    PubMed

    Zhu, Weifang; Zhao, Heming; Xiang, Dehui; Chen, Xinjian

    2013-01-01

    Empirical mode decomposition (EMD) is an adaptive method for nonlinear, non-stationary signal analysis. However, the upper and lower envelopes fitted by cubic spline interpolation (CSI) may often occur overshoots. In this paper, a new envelope fitting method based on the flattest constrained interpolation is proposed. The proposed method effectively integrates the difference between extremes into the cost function, and applies a chaos particle swarm optimization method to optimize the derivatives of the interpolation nodes. The proposed method was tested on three different types of data: ascertain signal, random signals and real electrocardiogram signals. The experimental results show that: (1) The proposed flattest envelope effectively solves the overshoots caused by CSI method and the artificial bends caused by piecewise parabola interpolation (PPI) method. (2) The index of orthogonality of the intrinsic mode functions (IMFs) based on the proposed method is 0.04054, 0.02222 ± 0.01468 and 0.04013 ± 0.03953 for the ascertain signal, random signals and electrocardiogram signals, respectively, which is lower than the CSI method and the PPI method, and means the IMFs are more orthogonal. (3) The index of energy conversation of the IMFs based on the proposed method is 0.96193, 0.93501 ± 0.03290 and 0.93041 ± 0.00429 for the ascertain signal, random signals and electrocardiogram signals, respectively, which is closer to 1 than the other two methods and indicates the total energy deviation amongst the components is smaller. (4) The comparisons of the Hilbert spectrums show that the proposed method overcomes the mode mixing problems very well, and make the instantaneous frequency more physically meaningful.

  2. A Flattest Constrained Envelope Approach for Empirical Mode Decomposition

    PubMed Central

    Zhu, Weifang; Zhao, Heming; Xiang, Dehui; Chen, Xinjian

    2013-01-01

    Empirical mode decomposition (EMD) is an adaptive method for nonlinear, non-stationary signal analysis. However, the upper and lower envelopes fitted by cubic spline interpolation (CSI) may often occur overshoots. In this paper, a new envelope fitting method based on the flattest constrained interpolation is proposed. The proposed method effectively integrates the difference between extremes into the cost function, and applies a chaos particle swarm optimization method to optimize the derivatives of the interpolation nodes. The proposed method was tested on three different types of data: ascertain signal, random signals and real electrocardiogram signals. The experimental results show that: (1) The proposed flattest envelope effectively solves the overshoots caused by CSI method and the artificial bends caused by piecewise parabola interpolation (PPI) method. (2) The index of orthogonality of the intrinsic mode functions (IMFs) based on the proposed method is 0.04054, 0.02222±0.01468 and 0.04013±0.03953 for the ascertain signal, random signals and electrocardiogram signals, respectively, which is lower than the CSI method and the PPI method, and means the IMFs are more orthogonal. (3) The index of energy conversation of the IMFs based on the proposed method is 0.96193, 0.93501±0.03290 and 0.93041±0.00429 for the ascertain signal, random signals and electrocardiogram signals, respectively, which is closer to 1 than the other two methods and indicates the total energy deviation amongst the components is smaller. (4) The comparisons of the Hilbert spectrums show that the proposed method overcomes the mode mixing problems very well, and make the instantaneous frequency more physically meaningful. PMID:23626721

  3. Envelope-receptor interactions in Nipah virus pathobiology.

    PubMed

    Lee, Benhur

    2007-04-01

    Nipah (NiV) and Hendra (HeV) viruses are members of the newly defined Henipavirus genus of the Paramyxoviridae. Nipah virus (NiV) is an emergent paramyxovirus that causes fatal encephalitis in up to 70% of infected patients, and there is increasing evidence of human-to-human transmission. NiV is designated a priority pathogen in the NIAID Biodefense Research Agenda, and could be a devastating agent of agrobioterrorism if used against the pig farming industry. Endothelial syncytium is a pathognomonic feature of NiV infections, and is mediated by the fusion (F) and attachment (G) envelope glycoproteins. This review summarizes what is known about the pathophysiology of NiV infections, and documents the identification of the NiV receptor. EphrinB2, the NiV and HeV receptor, is expressed on endothelial cells and neurons, consistent with the known cellular tropism for NiV. We discuss how the identification of the henipahvirus receptor sheds light on the pathobiology of NiV infection, and how it will spur the rational development of effective therapeutics. In addition, ephrinB3, a related protein, can serve as an alternative receptor, and we suggest that differential usage of ephrinB2 versus B3 may explain the variant pathogenic profiles observed between NiV and HeV. Thus, identifying the NiV receptors opens the door for a more comprehensive analysis of the envelope-receptor interactions in NiV pathobiology. Finally, we also describe how galectin-1 (an innate immune defense lectin) can interact with specific N-glycans on the Nipah envelope fusion protein, underscoring the potential role that innate immune defense mechanisms may play against emerging pathogens.

  4. Dynamic network data envelopment analysis for university hospitals evaluation

    PubMed Central

    Lobo, Maria Stella de Castro; Rodrigues, Henrique de Castro; André, Edgard Caires Gazzola; de Azeredo, Jônatas Almeida; Lins, Marcos Pereira Estellita

    2016-01-01

    ABSTRACT OBJECTIVE To develop an assessment tool to evaluate the efficiency of federal university general hospitals. METHODS Data envelopment analysis, a linear programming technique, creates a best practice frontier by comparing observed production given the amount of resources used. The model is output-oriented and considers variable returns to scale. Network data envelopment analysis considers link variables belonging to more than one dimension (in the model, medical residents, adjusted admissions, and research projects). Dynamic network data envelopment analysis uses carry-over variables (in the model, financing budget) to analyze frontier shift in subsequent years. Data were gathered from the information system of the Brazilian Ministry of Education (MEC), 2010-2013. RESULTS The mean scores for health care, teaching and research over the period were 58.0%, 86.0%, and 61.0%, respectively. In 2012, the best performance year, for all units to reach the frontier it would be necessary to have a mean increase of 65.0% in outpatient visits; 34.0% in admissions; 12.0% in undergraduate students; 13.0% in multi-professional residents; 48.0% in graduate students; 7.0% in research projects; besides a decrease of 9.0% in medical residents. In the same year, an increase of 0.9% in financing budget would be necessary to improve the care output frontier. In the dynamic evaluation, there was progress in teaching efficiency, oscillation in medical care and no variation in research. CONCLUSIONS The proposed model generates public health planning and programming parameters by estimating efficiency scores and making projections to reach the best practice frontier. PMID:27191158

  5. HIV Entry and Envelope Glycoprotein-mediated Fusion*

    PubMed Central

    Blumenthal, Robert; Durell, Stewart; Viard, Mathias

    2012-01-01

    HIV entry involves binding of the trimeric viral envelope glycoprotein (Env) gp120/gp41 to cell surface receptors, which triggers conformational changes in Env that drive the membrane fusion reaction. The conformational landscape that the lipids and Env navigate en route to fusion has been examined by biophysical measurements on the microscale, whereas electron tomography, x-rays, and NMR have provided insights into the process on the nanoscale and atomic scale. However, the coupling between the lipid and protein pathways that give rise to fusion has not been resolved. Here, we discuss the known and unknown about the overall HIV Env-mediated fusion process. PMID:23043104

  6. Scattering theory for the quantum envelope of a classical system

    SciTech Connect

    Sudarshan, E.C.G.

    1993-12-31

    Classical dynamics, reformulated in terms of its quantum envelope is studied for the stationary states of the interacting system. The dynamical variable of ``elapsed time`` plays a crucial role in this study. It is shown that the perturbation series for the elapsed time can be summed in various simple cases even when standard perturbation series diverge. For the special class of systems where the interactions fall off sufficiently fast at infinity one could define ``in`` and ``out`` states; and consequently the wave matrices and scattering matrices. The scattering phase shifts bear a simple relation to the time delay in scattering.

  7. BF Orionis - Evidence for an infalling circumstellar envelope

    NASA Technical Reports Server (NTRS)

    Welty, Alan D.; Barden, Samuel C.; Huenemoerder, David P.; Ramsey, Lawrence W.

    1992-01-01

    Analysis of the optical magnitudes and Balmer lines of the Herbig Ae/Be star BF Orionis confirm that the object is an early to mid A-type star, but appears to be below the zero-age main sequence. Enhanced metal-line strengths (once thought to link BF Ori with the Am stars), line asymmetries, and radial velocities are shown to be signatures of an infalling circumstellar envelope. The possibility that BF Ori has a late-type companion is examined, and it is concluded that it does not.

  8. Envelope model of a heavy-ion recirculator

    SciTech Connect

    Sharp, W.M.; Barnard, J.J.; Yu, S.S.

    1990-12-01

    A simple transport code has been developed to model the beam in a heavy-ion recirculating accelerator. The novel feature of the model is the treatment of the beam charge density as a Lagrangian fluid in the axial direction. In addition, the envelope and centroid equations include terms that account for the transverse self-force, image forces, and bend fields in the paraxial limit. The use of compressible'' beam slices makes the code suitable for designing the acceleration and compression schedules. The code has been used primarily to design the lattice of the LLNL recirculator, and preliminary magnet configurations for that machine are presented here. 3 refs., 2 figs.

  9. Genetics of Capsular Polysaccharides and Cell Envelope (Glyco)lipids

    PubMed Central

    Daffé, Mamadou; Crick, Dean C.; Jackson, Mary

    2014-01-01

    This chapter summarizes what is currently known of the structures, physiological roles, involvement in pathogenicity and biogenesis of a variety of non-covalently bound cell envelope lipids and glycoconjugates of Mycobacterium tuberculosis and other Mycobacterium species. Topics addressed in this chapter include phospholipids; phosphatidylinositol mannosides; triglycerides; isoprenoids and related compounds (polyprenyl phosphate, menaquinones, carotenoids, non-carotenoid cyclic isoprenoids); acyltrehaloses (lipooligosaccharides, trehalose mono- and di-mycolates, sulfolipids, di- and poly-acyltrehaloses); mannosyl-beta-1-phosphomycoketides; glycopeptidolipids; phthiocerol dimycocerosates, para-hydroxybenzoic acids and phenolic glycolipids; mycobactins; mycolactones; and capsular polysaccharides. PMID:25485178

  10. Thermonuclear runaways in thick hydrogen rich envelopes of neutron stars

    NASA Technical Reports Server (NTRS)

    Starrfield, S. G.; Kenyon, S.; Truran, J. W.; Sparks, W. M.

    1981-01-01

    A Lagrangian, fully implicit, one dimensional hydrodynamic computer code was used to evolve thermonuclear runaways in the accreted hydrogen rich envelopes of 1.0 Msub solar neutron stars with radii of 10 km and 20 km. Simulations produce outbursts which last from about 750 seconds to about one week. Peak effective temeratures and luninosities were 26 million K and 80 thousand Lsub solar for the 10 km study and 5.3 millison and 600 Lsub solar for the 20 km study. Hydrodynamic expansion on the 10 km neutron star produced a precursor lasting about one ten thousandth seconds.

  11. Safe Maneuvering Envelope Estimation Based on a Physical Approach

    NASA Technical Reports Server (NTRS)

    Lombaerts, Thomas J. J.; Schuet, Stefan R.; Wheeler, Kevin R.; Acosta, Diana; Kaneshige, John T.

    2013-01-01

    This paper discusses a computationally efficient algorithm for estimating the safe maneuvering envelope of damaged aircraft. The algorithm performs a robust reachability analysis through an optimal control formulation while making use of time scale separation and taking into account uncertainties in the aerodynamic derivatives. This approach differs from others since it is physically inspired. This more transparent approach allows interpreting data in each step, and it is assumed that these physical models based upon flight dynamics theory will therefore facilitate certification for future real life applications.

  12. Field Testing of Nano-PCM Enhanced Building Envelope Components

    SciTech Connect

    Biswas, Kaushik; Childs, Phillip W; Atchley, Jerald Allen

    2013-08-01

    The U.S. Department of Energy s (DOE) Building Technologies Program s goal of developing high-performance, energy efficient buildings will require more cost-effective, durable, energy efficient building envelopes. Forty-eight percent of the residential end-use energy consumption is spent on space heating and air conditioning. Reducing envelope-generated heating and cooling loads through application of phase change material (PCM)-enhanced envelope components can facilitate maximizing the energy efficiency of buildings. Field-testing of prototype envelope components is an important step in estimating their energy benefits. An innovative phase change material (nano-PCM) was developed with PCM encapsulated with expanded graphite (interconnected) nanosheets, which is highly conducive for enhanced thermal storage and energy distribution, and is shape-stable for convenient incorporation into lightweight building components. During 2012, two test walls with cellulose cavity insulation and prototype PCM-enhanced interior wallboards were installed in a natural exposure test (NET) facility at Charleston, SC. The first test wall was divided into four sections, which were separated by wood studs and thin layers of foam insulation. Two sections contained nano-PCM-enhanced wallboards: one was a three-layer structure, in which nano-PCM was sandwiched between two gypsum boards, and the other one had PCM dispersed homogeneously throughout graphite nanosheets-enhanced gypsum board. The second test wall also contained two sections with interior PCM wallboards; one contained nano-PCM dispersed homogeneously in gypsum and the other was gypsum board containing a commercial microencapsulated PCM (MEPCM) for comparison. Each test wall contained a section covered with gypsum board on the interior side, which served as control or a baseline for evaluation of the PCM wallboards. The walls were instrumented with arrays of thermocouples and heat flux transducers. Further, numerical modeling of

  13. Relative concordance of human immunodeficiency virus oligomeric and monomeric envelope in CCR5 coreceptor usage

    SciTech Connect

    Teeravechyan, Samaporn; Suphaphiphat, Pirada; Essex, Max; Lee, Tun-Hou

    2008-01-20

    A major difference between binding and fusion assays commonly used to study the human immunodeficiency virus (HIV) envelope is the use of monomeric envelope for the former assay and oligomeric envelope for the latter. Due to discrepancies in their readouts for some mutants, envelope regions involved in CCR5 coreceptor usage were systematically studied to determine whether the discordance is due to inherent differences between the two assays or whether it genuinely reflects functional differences at each entry step. By adding the binding inhibitor TAK-779 to delay coreceptor binding kinetics in the fusion assay, the readouts were found comparable between the assays for the mutants analysed in this study. Our finding indicates that monomeric binding reflects oligomeric envelope-CCR5 interaction, thus discordant results between binding and fusion assays do not necessarily indicate differences in coreceptor usage by oligomeric envelope and monomeric gp120.

  14. Immunogenicity of Escherichia coli expressed envelope 2 protein of Chikungunya virus

    PubMed Central

    Tripathi, Nagesh K; Priya, Raj; Shrivastava, Ambuj

    2014-01-01

    Chikungunya fever, a re-emerging infection, is an arthropod-borne viral disease prevalent in different parts of the world, particularly Africa and South East Asia. Chikungunya virus envelope 2 protein is involved in binding to host receptors and it contains specific epitopes that elicit virus neutralizing antibodies. A highly immunogenic, recombinant Chikungunya virus envelope 2 protein was produced by bioreactor in Escherichia coli for development of a suitable diagnostic and vaccine candidate. This protein was refolded and further purified to achieve biologically active protein. The biological function of refolded and purified recombinant envelope 2 protein of Chikungunya virus was confirmed by its ability to generate envelope 2 specific antibodies with high titers in animal models. These findings suggest that recombinant envelope 2 protein of Chikungunya virus in combination with compatible adjuvant is highly immunogenic. Thus, recombinant envelope 2 protein can be a potential diagnostic reagent and vaccine candidate against Chikungunya virus infection. PMID:24637708

  15. Differentiating speech and nonspeech sounds via amplitude envelope cues

    NASA Astrophysics Data System (ADS)

    Lehnhoff, Robert J.; Strange, Winifred; Long, Glenis

    2001-05-01

    Recent evidence from neuroscience and behavioral speech science suggests that the temporal modulation pattern of the speech signal plays a distinctive role in speech perception. As a first step in exploring the nature of the perceptually relevant information in the temporal pattern of speech, this experiment examined whether speech versus nonspeech environmental sounds could be differentiated on the basis of their amplitude envelopes. Conversational speech was recorded from native speakers of six different languages (French, German, Hebrew, Hindi, Japanese, and Russian) along with samples of their English. Nonspeech sounds included animal vocalizations, water sounds, and other environmental sounds (e.g., thunder). The stimulus set included 30 2-s speech segments and 30 2-s nonspeech events. Frequency information was removed from all stimuli using a technique described by Dorman et al. [J. Acoust. Soc. Am. 102 (1997)]. Nine normal-hearing adult listeners participated in the experiment. Subjects decided whether each sound was (originally) speech or nonspeech and rated their confidence (7-point Likert scale). Overall, subjects differentiated speech from nonspeech very accurately (84% correct). Only 12 stimuli were not correctly categorized at greater than chance levels. Acoustical analysis is underway to determine what parameters of the amplitude envelope differentiate speech from nonspeech sounds.

  16. A novel family of plant nuclear envelope-associated proteins.

    PubMed

    Pawar, Vidya; Poulet, Axel; Détourné, Gwénaëlle; Tatout, Christophe; Vanrobays, Emmanuel; Evans, David E; Graumann, Katja

    2016-10-01

    This paper describes the characterisation of a new family of higher plant nuclear envelope-associated proteins (NEAPs) that interact with other proteins of the nuclear envelope. In the model plant Arabidopsis thaliana, the family consists of three genes expressed ubiquitously (AtNEAP1-3) and a pseudogene (AtNEAP4). NEAPs consist of extensive coiled-coil domains, followed by a nuclear localisation signal and a C-terminal predicted transmembrane domain. Domain deletion mutants confirm the presence of a functional nuclear localisation signal and transmembrane domain. AtNEAP proteins localise to the nuclear periphery as part of stable protein complexes, are able to form homo- and heteromers, and interact with the SUN domain proteins AtSUN1 and AtSUN2, involved in the linker of nucleoskeleton and cytoskeleton (LINC) complex. An A. thaliana cDNA library screen identified a putative transcription factor called AtbZIP18 as a novel interactor of AtNEAP1, which suggest a connection between NEAP and chromatin. An Atneap1 Atneap3 double-knockout mutant showed reduced root growth, and altered nuclear morphology and chromatin structure. Thus AtNEAPs are suggested as inner nuclear membrane-anchored coiled-coil proteins with roles in maintaining nuclear morphology and chromatin structure.

  17. Case Study of Envelope Sealing in Existing Multiunit Structures

    SciTech Connect

    Dentz, J.; Conlin, F.; Podorson, D.

    2012-10-01

    Envelope air sealing was included in the retrofit of a 244 unit low-rise multifamily housing complex in Durham, N.C. Pre- and post-retrofit enclosure leakage tests were conducted on 51 units and detailed diagnostics were performed on 16. On average, total leakage was reduced by nearly half, from 19.7 ACH50 to 9.4 ACH50. Costs for air sealing were $0.31 per square foot of conditioned floor area, lower than estimates found in the National Residential Efficiency Measures Database (NREMD) and other sources, perhaps due in part to the large-scale production nature of the project. Modeling with BEopt software -- using an estimate of 85% of the envelope air leakage going to the outside (based on guarded tests performed at the site) -- calculated a space conditioning energy cost savings of 15% to 21% due to the air sealing retrofit. Important air leakage locations identified included plumbing and electrical penetrations, dropped ceilings/soffits, windows, ducts and wall-to-floor intersections. Previous repair activity had created significant leakage locations as well. Specifications and a pictorial guide were developed for contractors performing the work.

  18. Design of hydrodynamically confined microfluidics: controlling flow envelope and pressure.

    PubMed

    Christ, Kevin V; Turner, Kevin T

    2011-04-21

    Closed-channel microfluidic devices are widely used in a number of chemical and biological applications; however, it is often difficult to interact with samples, such as cells, that are enclosed inside them. Hydrodynamically confined microflows (HCMs) allow microfluidic-type flows to be generated in open liquid environments, such as Petri dishes, thus greatly increasing the flexibility of microfluidic approaches. HCMs have previously been used for protein patterning and selective cell treatment applications, but the underlying fluid mechanics is not fully understood. Here, we examine the effect of device geometry and flow parameters on the properties of the flow envelope and pressure drop of several two-port HCM devices using a combination of experiments and modeling. A three-port device, which allows for different flow envelope shapes to be generated, is also analyzed. The experimental results agree well with the 3-D computational fluid dynamics simulations, with the majority of the measurements within 10% of the simulations. The results presented provide a framework for understanding the fluid mechanics of HCMs and will aid in the design of HCM devices for a broad range of applications.

  19. Low-Frequency Envelope Sensitivity Produces Asymmetric Binaural Tuning Curves

    PubMed Central

    Agapiou, John P.; McAlpine, David

    2008-01-01

    Neurons in the auditory midbrain are sensitive to differences in the timing of sounds at the two ears—an important sound localization cue. We used broadband noise stimuli to investigate the interaural-delay sensitivity of low-frequency neurons in two midbrain nuclei: the inferior colliculus (IC) and the dorsal nucleus of the lateral lemniscus. Noise-delay functions showed asymmetries not predicted from a linear dependence on interaural correlation: a stretching along the firing-rate dimension (rate asymmetry), and a skewing along the interaural-delay dimension (delay asymmetry). These asymmetries were produced by an envelope-sensitive component to the response that could not entirely be accounted for by monaural or binaural nonlinearities, instead indicating an enhancement of envelope sensitivity at or after the level of the superior olivary complex. In IC, the skew-like asymmetry was consistent with intermediate-type responses produced by the convergence of ipsilateral peak-type inputs and contralateral trough-type inputs. This suggests a stereotyped pattern of input to the IC. In the course of this analysis, we were also able to determine the contribution of time and phase components to neurons' internal delays. These findings have important consequences for the neural representation of interaural timing differences and interaural correlation—cues critical to the perception of acoustic space. PMID:18753329

  20. Hospitals Productivity Measurement Using Data Envelopment Analysis Technique

    PubMed Central

    TORABIPOUR, Amin; NAJARZADEH, Maryam; ARAB, Mohammad; FARZIANPOUR, Freshteh; GHASEMZADEH, Roya

    2014-01-01

    Abstract Background This study aimed to measure the hospital productivity using data envelopment analysis (DEA) technique and Malmquist indices. Methods This is a cross sectional study in which the panel data were used in a 4 year period from 2007 to 2010. The research was implemented in 12 teaching and non-teaching hospitals of Ahvaz County. Data envelopment analysis technique and the Malmquist indices with an input-orientation approach, was used to analyze the data and estimation of productivity. Data were analyzed using the SPSS.18 and DEAP.2 software. Results Six hospitals (50%) had a value lower than 1, which represents an increase in total productivity and other hospitals were non-productive. the average of total productivity factor (TPF) was 1.024 for all hospitals, which represents a decrease in efficiency by 2.4% from 2007 to 2010. The average technical, technologic, scale and managerial efficiency change was 0.989, 1.008, 1.028, and 0.996 respectively. There was not a significant difference in mean productivity changes among teaching and non-teaching hospitals (P>0.05) (except in 2009 years). Conclusion Productivity rate of hospitals had an increasing trend generally. However, the total average of productivity was decreased in hospitals. Besides, between the several components of total productivity, variation of technological efficiency had the highest impact on reduce of total average of productivity. PMID:26060727

  1. Reconfigurable Control Design for the Full X-33 Flight Envelope

    NASA Technical Reports Server (NTRS)

    Cotting, M. Christopher; Burken, John J.

    2001-01-01

    A reconfigurable control law for the full X-33 flight envelope has been designed to accommodate a failed control surface and redistribute the control effort among the remaining working surfaces to retain satisfactory stability and performance. An offline nonlinear constrained optimization approach has been used for the X-33 reconfigurable control design method. Using a nonlinear, six-degree-of-freedom simulation, three example failures are evaluated: ascent with a left body flap jammed at maximum deflection; entry with a right inboard elevon jammed at maximum deflection; and landing with a left rudder jammed at maximum deflection. Failure detection and identification are accomplished in the actuator controller. Failure response comparisons between the nominal control mixer and the reconfigurable control subsystem (mixer) show the benefits of reconfiguration. Single aerosurface jamming failures are considered. The cases evaluated are representative of the study conducted to prove the adequate and safe performance of the reconfigurable control mixer throughout the full flight envelope. The X-33 flight control system incorporates reconfigurable flight control in the existing baseline system.

  2. Crystal Structure of the Japanese Encephalitis Virus Envelope Protein

    SciTech Connect

    Luca, Vincent C.; AbiMansour, Jad; Nelson, Christopher A.; Fremont, Daved H.

    2012-03-13

    Japanese encephalitis virus (JEV) is the leading global cause of viral encephalitis. The JEV envelope protein (E) facilitates cellular attachment and membrane fusion and is the primary target of neutralizing antibodies. We have determined the 2.1-{angstrom} resolution crystal structure of the JEV E ectodomain refolded from bacterial inclusion bodies. The E protein possesses the three domains characteristic of flavivirus envelopes and epitope mapping of neutralizing antibodies onto the structure reveals determinants that correspond to the domain I lateral ridge, fusion loop, domain III lateral ridge, and domain I-II hinge. While monomeric in solution, JEV E assembles as an antiparallel dimer in the crystal lattice organized in a highly similar fashion as seen in cryo-electron microscopy models of mature flavivirus virions. The dimer interface, however, is remarkably small and lacks many of the domain II contacts observed in other flavivirus E homodimers. In addition, uniquely conserved histidines within the JEV serocomplex suggest that pH-mediated structural transitions may be aided by lateral interactions outside the dimer interface in the icosahedral virion. Our results suggest that variation in dimer structure and stability may significantly influence the assembly, receptor interaction, and uncoating of virions.

  3. Design and performance of an integrated envelope/lighting system

    SciTech Connect

    Lee, E.S.; Selkowitz, S.E.

    1997-04-01

    Dynamic envelope/lighting systems offer the potential to achieve a near optimum energy-efficient environment meeting occupant needs throughout the year by adapting to dynamic meteorological conditions and changing occupant preferences in real time. With the dramatic increased functionality of the microprocessor, there is an untapped potential to make dynamic envelop/lighting systems easier to use, diagnose, and monitor, and to integrate them as part of a sophisticated building-wide control system. This study addresses the complex relationship between this energy-efficiency technology and many of the non-energy issues related to its potential acceptance by the building industry, architects, owners, and users. The authors demonstrate the concept of integrated dynamic systems with a prototype motorized venetian blind operated in synchronization with electric lighting and daylighting controls via an intelligent control system. Research work conducted with simulation software and reduced-scale and full-scale field tests is summarized. Much of this work is directly relevant to other active shading and daylighting systems on the market today and to state-of-the-art window systems yet to come (i.e., electrochromics).

  4. Do bioclimate variables improve performance of climate envelope models?

    USGS Publications Warehouse

    Watling, James I.; Romañach, Stephanie S.; Bucklin, David N.; Speroterra, Carolina; Brandt, Laura A.; Pearlstine, Leonard G.; Mazzotti, Frank J.

    2012-01-01

    Climate envelope models are widely used to forecast potential effects of climate change on species distributions. A key issue in climate envelope modeling is the selection of predictor variables that most directly influence species. To determine whether model performance and spatial predictions were related to the selection of predictor variables, we compared models using bioclimate variables with models constructed from monthly climate data for twelve terrestrial vertebrate species in the southeastern USA using two different algorithms (random forests or generalized linear models), and two model selection techniques (using uncorrelated predictors or a subset of user-defined biologically relevant predictor variables). There were no differences in performance between models created with bioclimate or monthly variables, but one metric of model performance was significantly greater using the random forest algorithm compared with generalized linear models. Spatial predictions between maps using bioclimate and monthly variables were very consistent using the random forest algorithm with uncorrelated predictors, whereas we observed greater variability in predictions using generalized linear models.

  5. A tenuous X-ray corona enveloping AE Aquarii

    NASA Astrophysics Data System (ADS)

    Venter, L. A.; Meintjes, P. J.

    2007-06-01

    In this paper we propose that the observed unpulsed X-ray emission in AE Aquarii is the result of a very tenuous hot corona associated with the secondary star, which is pumped magnetohydrodynamically by the propeller action of the fast rotating white dwarf. It is shown that the closed coronal field of the secondary star envelops a substantial portion of the binary system, including the fast rotating magnetized white dwarf. This implies that the propeller outflow of material in AE Aquarii is initiated inside an enveloping magnetic cavity. The outflow crossing the secondary dead-zone field constitutes a βgen = (8πρv2esc/B2) >> 1 plasma, acting as a magnetohydrodynamic generator resulting in the induction of field-aligned currents in these closed magnetospheric circuits where βcir = (8πnkT/B2) << 1. The Ohmic heating of the coronal circuit can readily account for a Tx >= 107 K plasma in the coronal flux tubes connecting the generator and the stellar surface. Further, the bremsstrahlung losses of the thermal electrons in the coronal circuit can readily drive the observed unpulsed X-ray luminosity of Lx ~ 1031 ergs -1, which correlates with the luminosity and relatively large source implied by recent XMM-Newton observations.

  6. Space station Platform Management System (PMS) replanning using resource envelopes

    NASA Technical Reports Server (NTRS)

    Bush, Joy Lee; Critchfield, Anna; Loomis, Audrey

    1987-01-01

    One of the responsibilities of the Space Station Platform Management System (PMS) is to maintain constraint-free, short-term plans for platform and free-flyer activities. Both the replanning function and the associated constraint-checking function are viewed as potentially requiring expert system assistance. The PMS Resource Envelope Scheduling System (PRESS) expert system, which is currently under development, is described. The PRESS capabilities will include the following: plan, replan, and perform constraint checking using resource envelopes resembling those required for telescience; initialize itself using the results fo a previous run; infer the replanning needs associated with a change in resource availability; allow the user to determine the level of interaction (including an advisory capability) with the system during execution; and generate both a graphic timeline and a report as output. The PRESS is being developed on an IBM PC/AT using TeKnowledge, Inc.'s M.1 expert system shell. The PRESS activity definitions and constraints are based on those defined for the Cosmic Background Explorer (COBE) mission scheduled for launch in early 1989.

  7. The Properties of Heavy Elements in Giant Planet Envelopes

    NASA Astrophysics Data System (ADS)

    Soubiran, François; Militzer, Burkhard

    2016-09-01

    The core-accretion model for giant planet formation suggests a two-layer picture for the initial structure of Jovian planets, with heavy elements in a dense core and a thick H-He envelope. Late planetesimal accretion and core erosion could potentially enrich the H-He envelope in heavy elements, which is supported by the threefold solar metallicity that was measured in Jupiter’s atmosphere by the Galileo entry probe. In order to reproduce the observed gravitational moments of Jupiter and Saturn, models for their interiors include heavy elements, Z, in various proportions. However, their effect on the equation of state of the hydrogen-helium mixtures has not been investigated beyond the ideal mixing approximation. In this article, we report results from ab initio simulations of fully interacting H-He-Z mixtures in order to characterize their equation of state and to analyze possible consequences for the interior structure and evolution of giant planets. Considering C, N, O, Si, Fe, MgO, and SiO2, we show that the behavior of heavy elements in H-He mixtures may still be represented by an ideal mixture if the effective volumes and internal energies are chosen appropriately. In the case of oxygen, we also compute the effect on the entropy. We find the resulting changes in the temperature-pressure profile to be small. A homogeneous distribution of 2% oxygen by mass changes the temperature in Jupiter’s interior by only 80 K.

  8. Type of silicate feature in oxygen rich stellar envelopes

    NASA Technical Reports Server (NTRS)

    Iyengar, K. V. K.; Rengarajan, T. N.

    1989-01-01

    In many astronomical studies, the emissivity function derived from the Trapezium emission feature has been used. A statistical study of a large sample of objects is described that deals with the applicability of this function (hereafter TR). For comparison, another emissivity function derived for lunar silicate (LS) sample 14321 was used which has a maximum at 10.2 microns instead of at 9.7 microns as for TR. The IRAS low resolution spectra sources classified as 7n was used which has a silicate absorption feature without any atomic line emission. Most of these sources are likely to be oxygen rich stellar envelopes or hotspots in molecular clouds. The central source as assumed to emit a Plankian spectrum characterized by a temperature (t) and an absorbing envelope with an emissivity dependence of type TR or LS. Values of t and tau, the absorption optical depth were obtained by minimizing chi(exp 2) between the observed and fitted spectra in the 7 to 13 micron range. Values of reduced chi(exp 2) were obtained by taking the noise listed in the LRS Catalog as standard deviation. The tau values obtained correspond to 9.7 microns for TR and 10.2 for LS.

  9. Differentiating speech and nonspeech sounds via amplitude envelope cues

    NASA Astrophysics Data System (ADS)

    Lehnhoff, Robert J.; Strange, Winifred; Long, Glenis

    2004-05-01

    Recent evidence from neuroscience and behavioral speech science suggests that the temporal modulation pattern of the speech signal plays a distinctive role in speech perception. As a first step in exploring the nature of the perceptually relevant information in the temporal pattern of speech, this experiment examined whether speech versus nonspeech environmental sounds could be differentiated on the basis of their amplitude envelopes. Conversational speech was recorded from native speakers of six different languages (French, German, Hebrew, Hindi, Japanese, and Russian) along with samples of their English. Nonspeech sounds included animal vocalizations, water sounds, and other environmental sounds (e.g., thunder). The stimulus set included 30 2-s speech segments and 30 2-s nonspeech events. Frequency information was removed from all stimuli using a technique described by Dorman et al. [J. Acoust. Soc. Am. 102 (1997)]. Nine normal-hearing adult listeners participated in the experiment. Subjects decided whether each sound was (originally) speech or nonspeech and rated their confidence (7-point Likert scale). Overall, subjects differentiated speech from nonspeech very accurately (84% correct). Only 12 stimuli were not correctly categorized at greater than chance levels. Acoustical analysis is underway to determine what parameters of the amplitude envelope differentiate speech from nonspeech sounds.

  10. Protein folding in the cell envelope of Escherichia coli.

    PubMed

    De Geyter, Jozefien; Tsirigotaki, Alexandra; Orfanoudaki, Georgia; Zorzini, Valentina; Economou, Anastassios; Karamanou, Spyridoula

    2016-07-26

    While the entire proteome is synthesized on cytoplasmic ribosomes, almost half associates with, localizes in or crosses the bacterial cell envelope. In Escherichia coli a variety of mechanisms are important for taking these polypeptides into or across the plasma membrane, maintaining them in soluble form, trafficking them to their correct cell envelope locations and then folding them into the right structures. The fidelity of these processes must be maintained under various environmental conditions including during stress; if this fails, proteases are called in to degrade mislocalized or aggregated proteins. Various soluble, diffusible chaperones (acting as holdases, foldases or pilotins) and folding catalysts are also utilized to restore proteostasis. These responses can be general, dealing with multiple polypeptides, with functional overlaps and operating within redundant networks. Other chaperones are specialized factors, dealing only with a few exported proteins. Several complex machineries have evolved to deal with binding to, integration in and crossing of the outer membrane. This complex protein network is responsible for fundamental cellular processes such as cell wall biogenesis; cell division; the export, uptake and degradation of molecules; and resistance against exogenous toxic factors. The underlying processes, contributing to our fundamental understanding of proteostasis, are a treasure trove for the development of novel antibiotics, biopharmaceuticals and vaccines.

  11. LINC'ing form and function at the nuclear envelope.

    PubMed

    Meinke, Peter; Schirmer, Eric C

    2015-09-14

    The nuclear envelope is an amazing piece of engineering. On one hand it is built like a mediaeval fortress with filament systems reinforcing its membrane walls and its double membrane structure forming a lumen like a castle moat. On the other hand its structure can adapt while maintaining its integrity like a reed bending in a river. Like a fortress it has guarded drawbridges in the nuclear pore complexes, but also has other mechanical means of communication. All this is enabled largely because of the LINC complex, a multi-protein structure that connects the intermediate filament nucleoskeleton across the lumen of the double membrane nuclear envelope to multiple cytoplasmic filament systems that themselves could act simultaneously both like mediaeval buttresses and like lines on a suspension bridge. Although many details of the greater LINC structure remain to be discerned, a number of recent findings are giving clues as to how its structural organization can yield such striking dynamic yet stable properties. Combining double- and triple-helical coiled-coils, intrinsic disorder and order, tissue-specific components, and intermediate filaments enables these unique properties.

  12. Focal Targeting of the Bacterial Envelope by Antimicrobial Peptides

    PubMed Central

    Rashid, Rafi; Veleba, Mark; Kline, Kimberly A.

    2016-01-01

    Antimicrobial peptides (AMPs) are utilized by both eukaryotic and prokaryotic organisms. AMPs such as the human beta defensins, human neutrophil peptides, human cathelicidin, and many bacterial bacteriocins are cationic and capable of binding to anionic regions of the bacterial surface. Cationic AMPs (CAMPs) target anionic lipids [e.g., phosphatidylglycerol (PG) and cardiolipins (CL)] in the cell membrane and anionic components [e.g., lipopolysaccharide (LPS) and lipoteichoic acid (LTA)] of the cell envelope. Bacteria have evolved mechanisms to modify these same targets in order to resist CAMP killing, e.g., lysinylation of PG to yield cationic lysyl-PG and alanylation of LTA. Since CAMPs offer a promising therapeutic alternative to conventional antibiotics, which are becoming less effective due to rapidly emerging antibiotic resistance, there is a strong need to improve our understanding about the AMP mechanism of action. Recent literature suggests that AMPs often interact with the bacterial cell envelope at discrete foci. Here we review recent AMP literature, with an emphasis on focal interactions with bacteria, including (1) CAMP disruption mechanisms, (2) delocalization of membrane proteins and lipids by CAMPs, and (3) CAMP sensing systems and resistance mechanisms. We conclude with new approaches for studying the bacterial membrane, e.g., lipidomics, high resolution imaging, and non-detergent-based membrane domain extraction. PMID:27376064

  13. Sexual coevolution of spermatophore envelopes and female genital traits in butterflies: Evidence of male coercion?

    PubMed

    Sánchez, Víctor; Cordero, Carlos

    2014-01-01

    Signa are sclerotized structures located on the inner wall of the corpus bursa of female Lepidoptera whose main function is tearing open spermatophores. The sexually antagonistic coevolution (SAC) hypothesis proposes that the thickness of spermatophore envelopes has driven the evolution of the females signa; this idea is based in the fact that in many lepidopterans female sexual receptivity is at least partially controlled by the volume of ejaculate remaining in the corpus bursa. According to the SAC hypothesis, males evolved thick spermatophore envelopes to delay the post-mating recovery of female sexual receptivity thus reducing sperm competition; in response, females evolved signa for breaking spermatophore envelopes faster, gaining access to the resources contained in them and reducing their intermating intervals; the evolution of signa, in turn, favored the evolution of even thicker spermatophore envelopes, and so on. We tested two predictions of the SAC hypothesis with comparative data on the thickness of spermatophore envelopes of eleven species of Heliconiinae butterflies. The first prediction is that the spermatophore envelopes of polyandrous species with signa will be thicker than those of monandrous species without signa. In agreement with this prediction, we found that the spermatophore envelopes of a polyandrous Heliconius species with signa are thicker than those of two monandrous Heliconius species without signa. The second prediction is that in some species with signa males could enforce monandry in females by evolving "very thick" spermatophore envelopes, in these species we predict that their spermatophore envelopes will be thicker than those of their closer polyandrous relatives with signa. In agreement with this prediction, we found that in two out of three comparisons, spermatophore envelopes of monandrous species with signa have thicker spermatophore envelopes than their closer polyandrous relatives with signa. Thus, our results support the

  14. Sexual coevolution of spermatophore envelopes and female genital traits in butterflies: Evidence of male coercion?

    PubMed Central

    Sánchez, Víctor

    2014-01-01

    Signa are sclerotized structures located on the inner wall of the corpus bursa of female Lepidoptera whose main function is tearing open spermatophores. The sexually antagonistic coevolution (SAC) hypothesis proposes that the thickness of spermatophore envelopes has driven the evolution of the females signa; this idea is based in the fact that in many lepidopterans female sexual receptivity is at least partially controlled by the volume of ejaculate remaining in the corpus bursa. According to the SAC hypothesis, males evolved thick spermatophore envelopes to delay the post-mating recovery of female sexual receptivity thus reducing sperm competition; in response, females evolved signa for breaking spermatophore envelopes faster, gaining access to the resources contained in them and reducing their intermating intervals; the evolution of signa, in turn, favored the evolution of even thicker spermatophore envelopes, and so on. We tested two predictions of the SAC hypothesis with comparative data on the thickness of spermatophore envelopes of eleven species of Heliconiinae butterflies. The first prediction is that the spermatophore envelopes of polyandrous species with signa will be thicker than those of monandrous species without signa. In agreement with this prediction, we found that the spermatophore envelopes of a polyandrous Heliconius species with signa are thicker than those of two monandrous Heliconius species without signa. The second prediction is that in some species with signa males could enforce monandry in females by evolving “very thick” spermatophore envelopes, in these species we predict that their spermatophore envelopes will be thicker than those of their closer polyandrous relatives with signa. In agreement with this prediction, we found that in two out of three comparisons, spermatophore envelopes of monandrous species with signa have thicker spermatophore envelopes than their closer polyandrous relatives with signa. Thus, our results support

  15. Residential commissioning to assess envelope and HVAC system performance

    SciTech Connect

    Wray, Craig P.; Sherman, Max H.

    2001-08-31

    Houses do not perform optimally or even as many codes and forecasts predict. For example, Walker et al. (1998a) found large variations in thermal distribution system efficiency, as much as a factor of two even between side-by-side houses with the same system design and installation crew. This and other studies (e.g., Jump et al. 1996) indicate that duct leakage testing and sealing can readily achieve a 25 to 30% reduction in installed cooling capacity and energy consumption. As another example, consider that the building industry has recognized for at least 20 years the substantial impact that envelope airtightness has on thermal loads, energy use, comfort, and indoor air quality. However, Walker et al. (1998a) found 50% variances in airtightness for houses with the same design and construction crews, within the same subdivision. A substantial reason for these problems is that few houses are now built or retrofitted using formal design procedures, most are field assembled from a large number of components, and there is no consistent process to identify problems or to correct them. Solving the problems requires field performance evaluations of houses using appropriate and agreed upon procedures. Many procedural elements already exist in a fragmented environment; some are ready now to be integrated into a new process called residential commissioning (Wray et al. 2000). For example, California's Title 24 energy code already provides some commissioning elements for evaluating the energy performance of new houses. A house consists of components and systems that need to be commissioned, such as building envelopes, air distribution systems, cooling equipment, heat pumps, combustion appliances, controls, and other electrical appliances. For simplicity and practicality, these components and systems are usually evaluated individually, but we need to bear in mind that many of them interact. Therefore, commissioning must not only identify the energy and non-energy benefits

  16. Immunogenicity and efficacy of flagellin-envelope fusion dengue vaccines in mice and monkeys.

    PubMed

    Liu, Ge; Song, Langzhou; Beasley, David W C; Putnak, Robert; Parent, Jason; Misczak, John; Li, Hong; Reiserova, Lucia; Liu, Xiangyu; Tian, Haijun; Liu, Wenzhe; Labonte, Darlene; Duan, Lihua; Kim, Youngsun; Travalent, Linda; Wigington, Devin; Weaver, Bruce; Tussey, Lynda

    2015-05-01

    The envelope (E) protein of flaviviruses includes three domains, EI, EII, and EIII, and is the major protective antigen. Because EIII is rich in type-specific and subcomplex-specific neutralizing epitopes and is easy to express, it is particularly attractive as a recombinant vaccine antigen. VaxInnate has developed a vaccine platform that genetically links vaccine antigens to bacterial flagellin, a Toll-like receptor 5 ligand. Here we report that tetravalent dengue vaccines (TDVs) consisting of four constructs, each containing two copies of EIII fused to flagellin (R3.2x format), elicited robust and long-lived neutralizing antibodies (geometric mean titers of 200 to 3,000), as measured with a 50% focus reduction neutralization test (FRNT50). In an immunogenicity study, rhesus macaques (n = 2) immunized subcutaneously with 10 μg or 90 μg of TDV three or four times, at 4- to 6-week intervals, developed neutralizing antibodies to four dengue virus (DENV) serotypes (mean post-dose 3 FRNT50 titers of 102 to 601). In an efficacy study, rhesus macaques (n = 4) were immunized intramuscularly with 16 μg or 48 μg of TDV or a placebo control three times, at 1-month intervals. The animals that received 48-μg doses of TDV developed neutralizing antibodies against the four serotypes (geometric mean titers of 49 to 258) and exhibited reduced viremia after DENV-2 challenge, with a group mean viremia duration of 1.25 days and 2 of 4 animals being completely protected, compared to the placebo-treated animals, which all developed viremia, with a mean duration of 4 days. In conclusion, flagellin-EIII fusion vaccines are immunogenic and partially protective in a nonhuman primate model.

  17. Immunogenicity and Efficacy of Flagellin-Envelope Fusion Dengue Vaccines in Mice and Monkeys

    PubMed Central

    Song, Langzhou; Beasley, David W. C.; Putnak, Robert; Parent, Jason; Misczak, John; Li, Hong; Reiserova, Lucia; Liu, Xiangyu; Tian, Haijun; Liu, Wenzhe; Labonte, Darlene; Duan, Lihua; Kim, Youngsun; Travalent, Linda; Wigington, Devin; Weaver, Bruce; Tussey, Lynda

    2015-01-01

    The envelope (E) protein of flaviviruses includes three domains, EI, EII, and EIII, and is the major protective antigen. Because EIII is rich in type-specific and subcomplex-specific neutralizing epitopes and is easy to express, it is particularly attractive as a recombinant vaccine antigen. VaxInnate has developed a vaccine platform that genetically links vaccine antigens to bacterial flagellin, a Toll-like receptor 5 ligand. Here we report that tetravalent dengue vaccines (TDVs) consisting of four constructs, each containing two copies of EIII fused to flagellin (R3.2x format), elicited robust and long-lived neutralizing antibodies (geometric mean titers of 200 to 3,000), as measured with a 50% focus reduction neutralization test (FRNT50). In an immunogenicity study, rhesus macaques (n = 2) immunized subcutaneously with 10 μg or 90 μg of TDV three or four times, at 4- to 6-week intervals, developed neutralizing antibodies to four dengue virus (DENV) serotypes (mean post-dose 3 FRNT50 titers of 102 to 601). In an efficacy study, rhesus macaques (n = 4) were immunized intramuscularly with 16 μg or 48 μg of TDV or a placebo control three times, at 1-month intervals. The animals that received 48-μg doses of TDV developed neutralizing antibodies against the four serotypes (geometric mean titers of 49 to 258) and exhibited reduced viremia after DENV-2 challenge, with a group mean viremia duration of 1.25 days and 2 of 4 animals being completely protected, compared to the placebo-treated animals, which all developed viremia, with a mean duration of 4 days. In conclusion, flagellin-EIII fusion vaccines are immunogenic and partially protective in a nonhuman primate model. PMID:25761459

  18. Enhancement of speech intelligibility in reverberant rooms: role of amplitude envelope and temporal fine structure.

    PubMed

    Srinivasan, Nirmal Kumar; Zahorik, Pavel

    2014-06-01

    The temporal envelope and fine structure of speech make distinct contributions to the perception of speech in normal-hearing listeners, and are differentially affected by room reverberation. Previous work has demonstrated enhanced speech intelligibility in reverberant rooms when prior exposure to the room was provided. Here, the relative contributions of envelope and fine structure cues to this intelligibility enhancement were tested using an open-set speech corpus and virtual auditory space techniques to independently manipulate the speech cues within a simulated room. Intelligibility enhancement was observed only when the envelope was reverberant, indicating that the enhancement is envelope-based.

  19. Illusory position shift induced by motion within a moving envelope during smooth-pursuit eye movements.

    PubMed

    Hisakata, Rumi; Terao, Masahiko; Murakami, Ikuya

    2013-10-30

    The static envelope of a Gabor patch with a moving carrier appears to shift in the direction of the carrier motion; this phenomenon is known as the motion-induced position shift (De Valois & De Valois, 1991; Ramachandran & Anstis, 1990). This conventional stimulus configuration contains at least three covarying factors: the retinal carrier velocity, the environmental carrier velocity, and the carrier velocity relative to the envelope velocity, which happens to be zero. We manipulated these velocities independently to identify which is critical, and we measured the perceived position of the moving Gabor patch relative to a reference stimulus moving in the same direction at the same speed. In the first experiment, the position of the moving envelope observed with fixation appeared to shift in the direction of the carrier velocity relative to the envelope velocity. Furthermore, the illusion was more pronounced when the carrier moved in a direction opposite to that of the envelope. In the second and third experiments, we measured the illusion during smooth-pursuit eye movement in which the envelope was either static or moving, thereby dissociating retinal and environmental velocities. Under all conditions, the illusion occurred according to the envelope-relative velocity of the carrier. Additionally, the illusion was more pronounced when the carrier and envelope moved in opposite directions. We conclude that the carrier's envelope-relative velocity is the primary determinant of the motion-induced position shift.

  20. Final Step of Phosphatidic Acid Synthesis in Pea Chloroplasts Occurs in the Inner Envelope Membrane 1

    PubMed Central

    Andrews, Jaen; Ohlrogge, John B.; Keegstra, Kenneth

    1985-01-01

    The second enzyme of phosphatidic acid synthesis from glycerol-3-phosphate, 1-acylglycerophospate acyltransferase, was localized to the inner envelope membrane of pea chloroplasts. The activity of this enzyme was measured by both a coupled enzyme assay and a direct enzyme assay. Using the coupled enzyme assay, phosphatidic acid phosphatase was also localized to the inner envelope membrane, although this enzyme has very low activity in pea chloroplasts. The addition of UDP-galactose to unfractionated pea chloroplast envelope preparations did not result in significant conversion of newly synthesized diacylglycerol to monogalactosyldiacylglycerol. Thus, the envelope synthesized phosphatidic acid may not be involved in galactolipid synthesis in pea chloroplasts. PMID:16664266

  1. The effect of common-envelope evolution on the visible population of post-common-envelope binaries

    NASA Astrophysics Data System (ADS)

    Toonen, S.; Nelemans, G.

    2013-09-01

    Context. An important ingredient in binary evolution is the common-envelope (CE) phase. Although this phase is believed to be responsible for the formation of many close binaries, the process is not well understood. Aims: We investigate the characteristics of the population of post-common-envelope binaries (PCEB). As the evolution of these binaries and their stellar components are relatively simple, this population can be directly used to constraint CE evolution. Methods: We use the binary population synthesis code SeBa to simulate the current-day population of PCEBs in the Galaxy. We incorporate the selection effects in our model that are inherent to the general PCEB population and that are specific to the SDSS survey, which enables a direct comparison for the first time between the synthetic and observed population of visible PCEBs. Results: We find that selection effects do not play a significant role on the period distribution of visible PCEBs. To explain the observed dearth of long-period systems, the α-CE efficiency of the main evolutionary channel must be low. In the main channel, the CE is initiated by a red giant as it fills its Roche lobe in a dynamically unstable way. Other evolutionary paths cannot be constrained more. Additionally our model reproduces well the observed space density, the fraction of visible PCEBs amongst white dwarf (WD)-main sequence (MS) binaries, and the WD mass versus MS mass distribution, but overestimates the fraction of PCEBs with helium WD companions.

  2. Replication and neutralization of human immunodeficiency virus type 1 lacking the V1 and V2 variable loops of the gp120 envelope glycoprotein.

    PubMed Central

    Cao, J; Sullivan, N; Desjardin, E; Parolin, C; Robinson, J; Wyatt, R; Sodroski, J

    1997-01-01

    A human immunodeficiency virus type 1 (HIV-1) mutant lacking the V1 and V2 variable loops in the gp120 exterior envelope glycoprotein replicated in Jurkat lymphocytes with only modest delays compared with the wild-type virus. Revertants that replicated with wild-type efficiency rapidly emerged and contained only a few amino acid changes in the envelope glycoproteins compared with the parent virus. Both the parent and revertant viruses exhibited increased sensitivity to neutralization by antibodies directed against the V3 loop or a CD4-induced epitope on gp120 but not by soluble CD4 or an antibody against the CD4 binding site. This result demonstrates the role of the gp120 V1 and V2 loops in protecting HIV-1 from some subsets of neutralizing antibodies. PMID:9371651

  3. Oligomeric rearrangement of tick-borne encephalitis virus envelope proteins induced by an acidic pH.

    PubMed Central

    Allison, S L; Schalich, J; Stiasny, K; Mandl, C W; Kunz, C; Heinz, F X

    1995-01-01

    The flavivirus envelope protein E undergoes irreversible conformational changes at a mildly acidic pH which are believed to be necessary for membrane fusion in endosomes. In this study we used a combination of chemical cross-linking and sedimentation analysis to show that the envelope proteins of the flavivirus tick-borne encephalitis virus also change their oligomeric structure when exposed to a mildly acidic environment. Under neutral or slightly alkaline conditions, protein E on the surface of native virions exists as a homodimer which can be isolated by solubilization with the nonionic detergent Triton X-100. Solubilization with the same detergent after pretreatment at an acidic pH, however, yielded homotrimers rather than homodimers, suggesting that exposure to an acidic pH had induced a simultaneous weakening of dimeric contacts and a strengthening of trimeric ones. The pH threshold for the dimer-to-trimer transition was found to be 6.5. Because the pH dependence of this transition parallels that of previously observed changes in the conformation and hydrophobicity of protein E and that of virus-induced membrane fusion, it appears likely that the mechanism of fusion with endosomal membranes involves a specific rearrangement of the proteins in the viral envelope. Immature virions in which protein E is associated with the uncleaved precursor (prM) of the membrane protein M did not undergo a low-pH-induced rearrangement. This is consistent with a protective role of protein prM for protein E during intracellular transport of immature virions through acidic compartments of the trans-Golgi network. PMID:7529335

  4. Diagnostics of the unstable envelopes of Wolf-Rayet stars

    NASA Astrophysics Data System (ADS)

    Grassitelli, L.; Chené, A.-N.; Sanyal, D.; Langer, N.; St-Louis, N.; Bestenlehner, J. M.; Fossati, L.

    2016-05-01

    Context. The envelopes of stars near the Eddington limit are prone to various instabilities. A high Eddington factor in connection with the iron opacity peak leads to convective instability, and a corresponding envelope inflation may induce pulsational instability. Here, we investigate the occurrence and consequences of both instabilities in models of Wolf-Rayet stars. Aims: We determine the convective velocities in the sub-surface convective zones to estimate the amplitude of the turbulent velocity at the base of the wind that potentially leads to the formation of small-scale wind structures, as observed in several Wolf-Rayet stars. We also investigate the effect of stellar wind mass loss on the pulsations of our stellar models. Methods: We approximated solar metallicity Wolf-Rayet stars in the range 2-17 M⊙ by models of mass-losing helium stars, computed with the Bonn stellar evolution code. We characterized the properties of convection in the envelope of these stars adopting the standard mixing length theory. Results: Our results show the occurrence of sub-surface convective regions in all studied models. Small (≈1 km s-1) surface velocity amplitudes are predicted for models with masses below ≈10 M⊙. For models with M ≳ 10 M⊙, the surface velocity amplitudes are of the order of 10 km s-1. Moreover we find the occurrence of pulsations for stars in the mass range 9-14 M⊙, while mass loss appears to stabilize the more massive Wolf-Rayet stars. We confront our results with observationally derived line variabilities of 17 WN stars, of which we analysed eight here for the first time. The data suggest variability to occur for stars above 10 M⊙, which is increasing linearly with mass above this value, in agreement with our results. We further find our models in the mass range 9-14M⊙ to be unstable to radial pulsations, and predict local magnetic fields of the order of hundreds of gauss in Wolf-Rayet stars more massive than ≈10 M⊙. Conclusions: Our

  5. Beyond the Jamming Avoidance Response: weakly electric fish respond to the envelope of social electrosensory signals.

    PubMed

    Stamper, Sarah A; Madhav, Manu S; Cowan, Noah J; Fortune, Eric S

    2012-12-01

    Recent studies have shown that central nervous system neurons in weakly electric fish respond to artificially constructed electrosensory envelopes, but the behavioral relevance of such stimuli is unclear. Here we investigate the possibility that social context creates envelopes that drive behavior. When Eigenmannia virescens are in groups of three or more, the interactions between their pseudo-sinusoidal electric fields can generate 'social envelopes'. We developed a simple mathematical prediction for how fish might respond to such social envelopes. To test this prediction, we measured the responses of E. virescens to stimuli consisting of two sinusoids, each outside the range of the Jamming Avoidance Response (JAR), that when added to the fish's own electric field produced low-frequency (below 10 Hz) social envelopes. Fish changed their electric organ discharge (EOD) frequency in response to these envelopes, which we have termed the Social Envelope Response (SER). In 99% of trials, the direction of the SER was consistent with the mathematical prediction. The SER was strongest in response to the lowest initial envelope frequency tested (2 Hz) and depended on stimulus amplitude. The SER generally resulted in an increase of the envelope frequency during the course of a trial, suggesting that this behavior may be a mechanism for avoiding low-frequency social envelopes. Importantly, the direction of the SER was not predicted by the superposition of two JAR responses: the SER was insensitive to the amplitude ratio between the sinusoids used to generate the envelope, but was instead predicted by the sign of the difference of difference frequencies.

  6. Thermal-envelop stone house, solar. Final technical report

    SciTech Connect

    Avery, S.C.

    1982-05-19

    The purpose of this project is to create a comfortable, low-cost heating system for a single-family house, without dependence on non-renewable energy sources. I have attempted to combine a simple solar air-heating collector with the thermal envelop concept (for thermal air circulation) and massive interior stone walls for heat storage. All building materials, with the exception of the solar glazing material and certain other solar components, are inexpensive and locally produced. Examples are: rough-cut hardwood lumber, sandstone (free for the gathering), galvanized roofing for absorberplate, concrete, concrete block, and cellulose insulation. The collector has operated with a relatively high degree of efficiency, though three 0.6 amp duct fans had to be installed in order to increase air circulation. The interior stonework has provided more than adequate heat storage, along with even heat radiation throughout cloudy periods. My main problem has been heat loss around the foundation.

  7. Hepatitis C Virus E2 Envelope Glycoprotein Core Structure

    SciTech Connect

    Kong, Leopold; Giang, Erick; Nieusma, Travis; Kadam, Rameshwar U.; Cogburn, Kristin E.; Hua, Yuanzi; Dai, Xiaoping; Stanfield, Robyn L.; Burton, Dennis R.; Ward, Andrew B.; Wilson, Ian A.; Law, Mansun

    2014-08-26

    Hepatitis C virus (HCV), a Hepacivirus, is a major cause of viral hepatitis, liver cirrhosis, and hepatocellular carcinoma. HCV envelope glycoproteins E1 and E2 mediate fusion and entry into host cells and are the primary targets of the humoral immune response. The crystal structure of the E2 core bound to broadly neutralizing antibody AR3C at 2.65 angstroms reveals a compact architecture composed of a central immunoglobulin-fold β sandwich flanked by two additional protein layers. The CD81 receptor binding site was identified by electron microscopy and site-directed mutagenesis and overlaps with the AR3C epitope. The x-ray and electron microscopy E2 structures differ markedly from predictions of an extended, three-domain, class II fusion protein fold and therefore provide valuable information for HCV drug and vaccine design.

  8. Consequences of a tight squeeze: Nuclear envelope rupture and repair.

    PubMed

    Isermann, Philipp; Lammerding, Jan

    2017-03-13

    Cell migration through tight spaces can induce substantial deformations of the nucleus and cause nuclear envelope (NE) rupture, resulting in uncontrolled exchange of nuclear and cytosolic proteins. These events can cause DNA damage and, in severe cases, nuclear fragmentation, challenging the integrity of the genomic material. Cells overcome NE ruptures during interphase by repairing the NE using components of the endosomal sorting complexes required for transport (ESCRT) machinery. Paralleling the molecular mechanism employed during NE reformation in late mitosis, ESCRT-III subunits and the associated AAA-ATPase VPS4B are recruited to NE rupture sites and help restore NE integrity. While these findings are common to many cell types, they are particularly relevant in the context of cancer metastasis, where nuclear deformation and rupture could drive genomic instability in invading cells and further promote cancer progression. At the same time, inhibiting NE repair may offer new therapeutic approaches to specifically target invasive cancer cells.

  9. Hydrodynamic models of a Cepheid atmosphere. I - Deep envelope models

    NASA Technical Reports Server (NTRS)

    Karp, A. H.

    1975-01-01

    The implicit hydrodynamic code of Kutter and Sparks has been modified to include radiative transfer effects. This modified code has been used to compute deep envelope models of a classical Cepheid with a period of 12 days. It is shown that in this particular model the hydrogen ionization region plays only a small role in producing the observed phase lag between the light and velocity curves. The cause of the bumps on the model's light curve is examined, and a mechanism is presented to explain those Cepheids with two secondary features on their light curves. This mechanism is shown to be consistent with the Hertzsprung sequence only if the evolutionary mass-luminosity law is used.

  10. Nuclear envelope protein MAN1 regulates clock through BMAL1

    PubMed Central

    Lin, Shu-Ting; Zhang, Luoying; Lin, Xiaoyan; Zhang, Linda Chen; Garcia, Valentina Elizabeth; Tsai, Chen-Wei; Ptáček, Louis; Fu, Ying-Hui

    2014-01-01

    Circadian clocks serve as internal pacemakers that influence many basic homeostatic processes; consequently, the expression and function of their components are tightly regulated by intricate networks of feedback loops that fine-tune circadian processes. Our knowledge of these components and pathways is far from exhaustive. In recent decades, the nuclear envelope has emerged as a global gene regulatory machine, although its role in circadian regulation has not been explored. We report that transcription of the core clock component BMAL1 is positively modulated by the inner nuclear membrane protein MAN1, which directly binds the BMAL1 promoter and enhances its transcription. Our results establish a novel connection between the nuclear periphery and circadian rhythmicity, therefore bridging two global regulatory systems that modulate all aspects of bodily functions. DOI: http://dx.doi.org/10.7554/eLife.02981.001 PMID:25182847

  11. Nonlinear Landau damping of wave envelopes in a quantum plasma

    NASA Astrophysics Data System (ADS)

    Chatterjee, Debjani; Misra, A. P.

    2016-10-01

    The nonlinear theory of Landau damping of electrostatic wave envelopes (WEs) is revisited in a quantum electron-positron pair plasma. Starting from a Wigner-Moyal equation coupled to the Poisson equation and applying the multiple scale technique, we derive a nonlinear Schrödinger (NLS) equation which governs the evolution of electrostatic WEs. It is shown that the coefficients of the NLS equation, including the nonlocal nonlinear term, which appears due to the resonant particles having a group velocity of the WEs, are significantly modified by the particle dispersion. The effects of the quantum parameter H (the ratio of the plasmon energy to the thermal energy densities), associated with the particle dispersion, are examined on the Landau damping rate of carrier waves, as well as on the modulational instability of WEs. It is found that the Landau damping rate and the decay rate of the solitary wave amplitude are greatly reduced compared to their classical values (H = 0).

  12. Modeling technical efficiency of inshore fishery using data envelopment analysis

    NASA Astrophysics Data System (ADS)

    Rahman, Rahayu; Zahid, Zalina; Khairi, Siti Shaliza Mohd; Hussin, Siti Aida Sheikh

    2016-10-01

    Fishery industry contributes significantly to the economy of Malaysia. This study utilized Data Envelopment Analysis application in estimating the technical efficiency of fishery in Terengganu, a state on the eastern coast of Peninsular Malaysia, based on multiple output, i.e. total fish landing and income of fishermen with six inputs, i.e. engine power, vessel size, number of trips, number of workers, cost and operation distance. The data were collected by survey conducted between November and December 2014. The decision making units (DMUs) involved 100 fishermen from 10 fishery areas. The result showed that the technical efficiency in Season I (dry season) and Season II (rainy season) were 90.2% and 66.7% respectively. About 27% of the fishermen were rated to be efficient during Season I, meanwhile only 13% of the fishermen achieved full efficiency 100% during Season II. The results also found out that there was a significance difference in the efficiency performance between the fishery areas.

  13. Nuclear envelope and genome interactions in cell fate

    PubMed Central

    Talamas, Jessica A.; Capelson, Maya

    2015-01-01

    The eukaryotic cell nucleus houses an organism’s genome and is the location within the cell where all signaling induced and development-driven gene expression programs are ultimately specified. The genome is enclosed and separated from the cytoplasm by the nuclear envelope (NE), a double-lipid membrane bilayer, which contains a large variety of trans-membrane and associated protein complexes. In recent years, research regarding multiple aspects of the cell nucleus points to a highly dynamic and coordinated concert of efforts between chromatin and the NE in regulation of gene expression. Details of how this concert is orchestrated and how it directs cell differentiation and disease are coming to light at a rapid pace. Here we review existing and emerging concepts of how interactions between the genome and the NE may contribute to tissue specific gene expression programs to determine cell fate. PMID:25852741

  14. Nucleosome functions in spindle assembly and nuclear envelope formation

    PubMed Central

    Zierhut, Christian; Funabiki, Hironori

    2016-01-01

    Summary Chromosomes are not only carriers of the genetic material, but also actively regulate the assembly of complex intracellular architectures. During mitosis, chromosome-induced microtubule polymerisation ensures spindle assembly in cells without centrosomes and plays a supportive role in centrosome-containing cells. Chromosomal signals also mediate post-mitotic nuclear envelope (NE) re-formation. Recent studies using novel approaches to manipulate histones in oocytes, where functions can be analysed in the absence of transcription, have established that nucleosomes, but not DNA alone, mediate the chromosomal regulation of spindle assembly and NE formation. Both processes require the generation of RanGTP by RCC1 recruited to nucleosomes but nucleosomes also acquire cell cycle stage specific regulators, Aurora B in mitosis and ELYS, the initiator of nuclear pore complex assembly, at mitotic exit. Here, we review the mechanisms by which nucleosomes control assembly and functions of the spindle and the NE, and discuss their implications for genome maintenance. PMID:26222742

  15. Disorder and size effects in the envelope-function approximation

    NASA Astrophysics Data System (ADS)

    Dargam, T. G.; Capaz, R. B.; Koiller, Belita

    1997-10-01

    We investigate the validity and limitations of the envelope-function approximation (EFA), widely accepted for the description of the electronic states of semiconductor heterostructures. We consider narrow quantum wells of GaAs confined by AlxGa1-xAs barriers. Calculations performed within the tight-binding approximation using ensembles of supercells are compared to the EFA results. Results for miniband widths in superlattices obtained in different approximations are also discussed. The main source of discrepancy for narrow wells is the treatment of alloy disorder within the virtual crystal approximation. We also test the two key assumptions of the EFA: (a) that the electronic wave functions have Bloch symmetry with well-defined k--> in the alloy region; (b) that the periodic parts of the Bloch functions are the same throughout the heterostructure. We show that inaccuracies are mainly due to the former assumption.

  16. Chemical stratification in white dwarf atmospheres and envelopes

    NASA Technical Reports Server (NTRS)

    Koester, D.

    1989-01-01

    Theoretical arguments supporting a new mechanism maintaining a homogeneously mixed composition in white dwarf atmospheres with traces of helium are presented. Diffusion time scales, meridional circulation, mass loss, accretion of interstellar matter, convection, and radiative levitation are discussed. Theoretically, layered envelopes, with hydrogen on top of helium and an abundance profile in the transition layer determined by diffusion equilibrium, are expected. In cases with observed helium and hydrogen in the atmosphere this means that the total hydrogen mass must be very small. The empirical evidence for such atmospheres are assessed, using a new grid of model atmospheres with stratified element abundances and applying it to typical mixed abundance cases at the hot end of the white dwarf temperature sequence.

  17. The supernova envelope shock origin of cosmic rays - A review

    NASA Astrophysics Data System (ADS)

    Colgate, Stirling A.

    The hydrodynamic shock origin of cosmic rays in the envelope of a Type I presupernova star is reviewed. The spectrum produced by the relativistic hydrodynamic shock is one power of E steeper than observed and so is unlikely to be the primary source of cosmic rays. On the other hand the possibility of accelerating ultrahigh energy particles to >~ 1018 eV is unique to the shock mechanism and currently no other suggested galactic or extragalactic site is likely. The nonrelativistic hydrodynamic supernova explosion shock becomes relativistic at an external mass fraction of (1-F) = 3 × 10-6 of the star that is composed primarily of helium plus heavier nuclei. The resulting ejected relativistic energy, (1-F) MΘ c2 ≅ 6 × 1048 ergs per SNI is roughly 1/5 that necessary to explain the Galactic cosmic ray energy. The resulting spectrum becomes, N(>E) ~ (1-F) ~ E-2.5, steeper than E-1.6 observed. The heavy nuclei are partially spalled in the shock transition and partially resynthesized in the postshock expansion for E <~ 1015 eV dependent upon the large number of pairs in the post-shock fluid. Above this energy the shock progresses in the magnetized photosphere. The high energy limit is ≅ 1021 eV due to the coronal density of the presupernova star. The objection to SN shock accelerated cosmic rays by adiabatic deceleration is questioned on the basis of the Alfvén wave scattering conditions. Ultrahigh energy particles escape because the wave excitation energy density is too low in the dimension of many Larmor radii necessary for scattering back to the SN remnant. Others escape if the energy density is too high. For all others between these two limits the immediately following matter of lower velocity and greater mass compresses and energizes previously trapped highe renergy particles, allowing them to escape at energies still higher than originally shock ejected from the supernova. The so-called piston that drives the envelope shock is the same, i.e. the SN bulk

  18. Integrated simulation and data envelopment analysis models in emergency department

    NASA Astrophysics Data System (ADS)

    Aminuddin, Wan Malissa Wan Mohd; Ismail, Wan Rosmanira

    2016-11-01

    This study aims to determine the best resource allocation and to increase the efficiency service of an emergency department in a public hospital in Kuala Lumpur. We integrate Discrete Event Simulation (DES) and three models of Data Envelopment Analysis (DEA); Input-oriented CCR model, Input-oriented BCC model and Super-Efficiency model to fulfill such objective. Based on the comparison of results taken from the DEA models, the combination of DES, Input-oriented BCC model and Super-Efficiency BCC model is seen to be the best resource allocation technique to be used for enhancing the hospital efficiency. The combination has reduced patients waiting time while improving the average utilization rate of hospital resources compared to the current situation.

  19. Low-Cost Phase Change Material for Building Envelopes

    SciTech Connect

    Abhari, Ramin

    2015-08-06

    A low-cost PCM process consisting of conversion of fats and oils to PCM-range paraffins, and subsequent “encapsulation” of the paraffin using conventional plastic compounding/pelletizing equipment was demonstrated. The PCM pellets produced were field-tested in a building envelope application. This involved combining the PCM pellets with cellulose insulation, whereby 33% reduction in peak heat flux and 12% reduction in heat gain was observed (average summertime performance). The selling price of the PCM pellets produced according to this low-cost process is expected to be in the $1.50-$3.00/lb range, compared to current encapsulated PCM price of about $7.00/lb. Whole-building simulations using corresponding PCM thermal analysis data suggest a payback time of 8 to 16 years (at current energy prices) for an attic insulation retrofit project in the Phoenix climate area.

  20. Dust mineralogy in the circumstellar envelope of SVS13

    NASA Astrophysics Data System (ADS)

    Fujiyoshi, T.; Wright, C.; Moore, T.

    It is of great interest to study the mineralogy of circumstellar dust around young stars as it represents the original constituents of planetesimals, hence of the rocky planets like our own Earth. To this end, we have obtained an N-band (8-13 µm) spectrum of a pre-main-sequence star SVS13, using the facility mid-infrared imaging spectrometer COMICS on the Japanese 8.2-m Subaru Telescope atop the summit of Mauna Kea, Hawaii. We have fitted various emissivities/absorption coefficients of dust species to the spectrum to examine dust mineralogy in the circumstellar envelope of this remarkable young star. In this presentation, we outline the modelling and highlight some of our findings.

  1. Pulse Shaped Constant Envelope 8-PSK Modulation Study

    NASA Technical Reports Server (NTRS)

    Tao, Jianping; Horan, Sheila

    1997-01-01

    This report provides simulation results for constant envelope pulse shaped 8 Level Phase Shift Keying (8 PSK) modulation for end to end system performance. In order to increase bandwidth utilization, pulse shaping is applied to signals before they are modulated. This report provides simulation results of power spectra and measurement of bit errors produced by pulse shaping in a non-linear channel with Additive White Gaussian Noise (AWGN). The pulse shaping filters can placed before (Type B) or after (Type A) signals are modulated. Three kinds of baseband filters, 5th order Butterworth, 3rd order Bessel and Square-Root Raised Cosine with different BTs or roll off factors, are utilized in the simulations. The simulations were performed on a Signal Processing Worksystem (SPW).

  2. Case study of the Mastin double-envelope house

    NASA Astrophysics Data System (ADS)

    Jones, R. F.; Dennehy, G.; Ghaffari, H. T.; Munson, G. E.

    1981-05-01

    An evaluation is made of a double-envelope house of Ekose, a design built by Robert Mastin in Middletown, Rhode Island. The home has two shells with an airspace between through which air can circulate. Performance monitoring of the house in the heating season showed that the requirements for auxiliary heat are very low, about 2.1 Btu per square foot of floor space per degree-day. Design changes are identified which could reduce the heating requirement even further. This ranks the house among the most energy-efficient building designs available today. It is concluded that the low heating needs of the house are due primarily to the excellent insulative value of the double shell.

  3. The Envelope of Physiological Motion of the First Carpometacarpal Joint

    PubMed Central

    Crisco, Joseph J.; Patel, Tarpit; Halilaj, Eni; Moore, Douglas C.

    2015-01-01

    Much of the hand's functional capacity is due to the versatility of the motions at the thumb carpometacarpal (CMC) joint, which are presently incompletely defined. The aim of this study was to develop a mathematical model to completely describe the envelope of physiological motion of the thumb CMC joint and then to examine if there were differences in the kinematic envelope between women and men. In vivo kinematics of the first metacarpal with respect to the trapezium were computed from computed tomography (CT) volume images of 44 subjects (20M, 24F, 40.3 ± 17.7 yr) with no signs of CMC joint pathology. Kinematics of the first metacarpal were described with respect to the trapezium using helical axis of motion (HAM) variables and then modeled with discrete Fourier analysis. Each HAM variable was fit in a cyclic domain as a function of screw axis orientation in the trapezial articular plane; the RMSE of the fits was 14.5 deg, 1.4 mm, and 0.8 mm for the elevation, location, and translation, respectively. After normalizing for the larger bone size in men, no differences in the kinematic variables between sexes could be identified. Analysis of the kinematic data also revealed notable coupling of the primary rotations of the thumb with translation and internal and external rotations. This study advances our basic understanding of thumb CMC joint function and provides a complete description of the CMC joint for incorporation into future models of hand function. From a clinical perspective, our findings provide a basis for evaluating CMC pathology, especially the mechanically mediated aspects of osteoarthritis (OA), and should be used to inform artificial joint design, where accurate replication of kinematics is essential for long-term success. PMID:26201612

  4. Morphology and kinematics of the gas envelope of Mira Ceti

    NASA Astrophysics Data System (ADS)

    Nhung, P. T.; Hoai, D. T.; Diep, P. N.; Phuong, N. T.; Thao, N. T.; Tuan-Anh, P.; Darriulat, P.

    2016-07-01

    Observations of 12CO(3-2) emission of the circumbinary envelope of Mira Ceti, made by Atacama Large Millimetre/sub-millimetre Array, are analysed. The observed Doppler velocity distribution is made of three components: a blueshifted south-eastern arc, which can be described as a ring in slow radial expansion, ˜1.7 km s-1, making an angle of ˜50° with the plane of the sky and born some 2000 years ago; a few arcs, probably born at the same epoch as the blueshifted arc, all sharing Doppler velocities redshifted by approximately 3±2 km s-1 with respect to the main star; thirdly, a central region dominated by the circumbinary envelope, displaying two outflows in the south-western and north-eastern hemispheres. At short distances from the star, up to ˜1.5 arcsec, these hemispheres display very different morphologies: the south-western outflow covers a broad solid angle, expands radially at a rate between 5 and 10 km s-1 and is slightly redshifted; the north-eastern outflow consists of two arms, both blueshifted, bracketing a broad dark region where emission is suppressed. At distances between ˜1.5 and ˜2.5 arcsec the asymmetry between the two hemispheres is significantly smaller and detached arcs, particularly spectacular in the north-eastern hemisphere are present. Close to the stars, we observe a mass of gas surrounding Mira B, with a size of a few tens of au, and having Doppler velocities with respect to Mira B reaching ±1.5 km s-1, which we interpret as gas flowing from Mira A towards Mira B.

  5. Photoevaporating stellar envelopes observed with Rayleigh beacon adaptive optics

    NASA Technical Reports Server (NTRS)

    Mccullough, P. R.; Fugate, R. Q.; Christou, J. C.; Ellerbroek, B. L.; Higgins, C. H.; Spinhirne, J. M.; Cleis, R. A.; Moroney, J. F.

    1995-01-01

    We present H-alpha and I-band images of a approximately 1 min diameter field centered on theta(sup 1) C Ori made with a unique adaptive optics system that uses either starlight or Rayleigh-backscattered laser light to correct for atmospheric wavefront distortion. Approximately one-half of the stars in this region are positionally associated with knots of ionized gas, which are interpreted as photoevaporating envelopes of low-mass stars. The acronyms 'partially ionized globule' (PIGs), external ionized (accretion) disks in the environs of radiation sources (EIDERs), or protoplanetary disks (ProPlyDs) all refer to these same knots. The H-alpha fluxes of the PIGs are proportional to their 2 cm radio continumm flux densities, and for nearly all the ionized knots, the 2 cm brightness temperatures are consistent with theta(sup 1) C Ori as the primary source of ionization. The comet-like morphology of the bright nebulosities is modeled as the result of an equilibrium between photoionization, recombination, and shadowing. The radii of the ionized 'head' of the cometary PIGs grow with distance from theta(sup 1) C Ori; the radii range from approximately less than or equal to 0.05 sec to approximately 0.25 sec. We interpret the size-distance relationship as evidence that the envelopes all have the same density profile and mass-loss rate within a factor of 2. Faint, arcuate wisps are observed 1 sec to 2 sec distance from some of the cometary nebulosities; these are modeled as bow shocks caused by the wind from theta(sup 1) C Ori. The positions of the stars associated with the PIGs in the observational H-R diagram indicate they are pre-main-sequence stars with masses less than approximately 3 solar mass, with approximately 1 solar mass being typical. Their medium I-K color is 2.9.

  6. Towards a Diagnosis of Cochlear Neuropathy with Envelope Following Responses.

    PubMed

    Shaheen, Luke A; Valero, Michelle D; Liberman, M Charles

    2015-12-01

    Listeners with normal audiometric thresholds can still have suprathreshold deficits, for example, in the ability to discriminate sounds in complex acoustic scenes. One likely source of these deficits is cochlear neuropathy, a loss of auditory nerve (AN) fibers without hair cell damage, which can occur due to both aging and moderate acoustic overexposure. Since neuropathy can affect up to 50 % of AN fibers, its impact on suprathreshold hearing is likely profound, but progress is hindered by lack of a robust non-invasive test of neuropathy in humans. Reduction of suprathreshold auditory brainstem responses (ABRs) can be used to quantify neuropathy in inbred mice. However, ABR amplitudes are highly variable in humans, and thus more challenging to use. Since noise-induced neuropathy is selective for AN fibers with high thresholds, and because phase locking to temporal envelopes is particularly strong in these fibers, the envelope following response (EFR) might be a more robust measure. We compared EFRs to sinusoidally amplitude-modulated tones and ABRs to tone-pips in mice following a neuropathic noise exposure. EFR amplitude, EFR phase-locking value, and ABR amplitude were all reduced in noise-exposed mice. However, the changes in EFRs were more robust: the variance was smaller, thus inter-group differences were clearer. Optimum detection of neuropathy was achieved with high modulation frequencies and moderate levels. Analysis of group delays was used to confirm that the AN population was dominating the responses at these high modulation frequencies. Application of these principles in clinical testing can improve the differential diagnosis of sensorineural hearing loss.

  7. NET23/STING promotes chromatin compaction from the nuclear envelope.

    PubMed

    Malik, Poonam; Zuleger, Nikolaj; de las Heras, Jose I; Saiz-Ros, Natalia; Makarov, Alexandr A; Lazou, Vassiliki; Meinke, Peter; Waterfall, Martin; Kelly, David A; Schirmer, Eric C

    2014-01-01

    Changes in the peripheral distribution and amount of condensed chromatin are observed in a number of diseases linked to mutations in the lamin A protein of the nuclear envelope. We postulated that lamin A interactions with nuclear envelope transmembrane proteins (NETs) that affect chromatin structure might be altered in these diseases and so screened thirty-one NETs for those that promote chromatin compaction as determined by an increase in the number of chromatin clusters of high pixel intensity. One of these, NET23 (also called STING, MITA, MPYS, ERIS, Tmem173), strongly promoted chromatin compaction. A correlation between chromatin compaction and endogenous levels of NET23/STING was observed for a number of human cell lines, suggesting that NET23/STING may contribute generally to chromatin condensation. NET23/STING has separately been found to be involved in innate immune response signaling. Upon infection cells make a choice to either apoptose or to alter chromatin architecture to support focused expression of interferon genes and other response factors. We postulate that the chromatin compaction induced by NET23/STING may contribute to this choice because the cells expressing NET23/STING eventually apoptose, but the chromatin compaction effect is separate from this as the condensation was still observed when cells were treated with Z-VAD to block apoptosis. NET23/STING-induced compacted chromatin revealed changes in epigenetic marks including changes in histone methylation and acetylation. This indicates a previously uncharacterized nuclear role for NET23/STING potentially in both innate immune signaling and general chromatin architecture.

  8. Polymers in cell encapsulation from an enveloped cell perspective.

    PubMed

    de Vos, Paul; Lazarjani, Hamideh Aghajani; Poncelet, Denis; Faas, Marijke M

    2014-04-01

    In the past two decades, many polymers have been proposed for producing immunoprotective capsules. Examples include the natural polymers alginate, agarose, chitosan, cellulose, collagen, and xanthan and synthetic polymers poly(ethylene glycol), polyvinyl alcohol, polyurethane, poly(ether-sulfone), polypropylene, sodium polystyrene sulfate, and polyacrylate poly(acrylonitrile-sodium methallylsulfonate). The biocompatibility of these polymers is discussed in terms of tissue responses in both the host and matrix to accommodate the functional survival of the cells. Cells should grow and function in the polymer network as adequately as in their natural environment. This is critical when therapeutic cells from scarce cadaveric donors are considered, such as pancreatic islets. Additionally, the cell mass in capsules is discussed from the perspective of emerging new insights into the release of so-called danger-associated molecular pattern molecules by clumps of necrotic therapeutic cells. We conclude that despite two decades of intensive research, drawing conclusions about which polymer is most adequate for clinical application is still difficult. This is because of the lack of documentation on critical information, such as the composition of the polymer, the presence or absence of confounding factors that induce immune responses, toxicity to enveloped cells, and the permeability of the polymer network. Only alginate has been studied extensively and currently qualifies for application. This review also discusses critical issues that are not directly related to polymers and are not discussed in the other reviews in this issue, such as the functional performance of encapsulated cells in vivo. Physiological endocrine responses may indeed not be expected because of the many barriers that the metabolites encounter when traveling from the blood stream to the enveloped cells and back to circulation. However, despite these diffusion barriers, many studies have shown optimal

  9. A New Approach to Produce HIV-1 Envelope Trimers

    PubMed Central

    AlSalmi, Wadad; Mahalingam, Marthandan; Ananthaswamy, Neeti; Hamlin, Christopher; Flores, Dalia; Gao, Guofen; Rao, Venigalla B.

    2015-01-01

    The trimeric envelope spike of HIV-1 mediates virus entry into human cells. The exposed part of the trimer, gp140, consists of two noncovalently associated subunits, gp120 and gp41 ectodomain. A recombinant vaccine that mimics the native trimer might elicit entry-blocking antibodies and prevent virus infection. However, preparation of authentic HIV-1 trimers has been challenging. Recently, an affinity column containing the broadly neutralizing antibody 2G12 has been used to capture recombinant gp140 and prepare trimers from clade A BG505 that naturally produces stable trimers. However, this antibody-based approach may not be as effective for the diverse HIV-1 strains with different epitope signatures. Here, we report a new and simple approach to produce HIV-1 envelope trimers. The C terminus of gp140 was attached to Strep-tag II with a long linker separating the tag from the massive trimer base and glycan shield. This allowed capture of nearly homogeneous gp140 directly from the culture medium. Cleaved, uncleaved, and fully or partially glycosylated trimers from different clade viruses were produced. Extensive biochemical characterizations showed that cleavage of gp140 was not essential for trimerization, but it triggered a conformational change that channels trimers into correct glycosylation pathways, generating compact three-blade propeller-shaped trimers. Uncleaved trimers entered aberrant pathways, resulting in hyperglycosylation, nonspecific cross-linking, and conformational heterogeneity. Even the cleaved trimers showed microheterogeneity in gp41 glycosylation. These studies established a broadly applicable HIV-1 trimer production system as well as generating new insights into their assembly and maturation that collectively bear on the HIV-1 vaccine design. PMID:26088135

  10. NET23/STING Promotes Chromatin Compaction from the Nuclear Envelope

    PubMed Central

    de las Heras, Jose I.; Saiz-Ros, Natalia; Makarov, Alexandr A.; Lazou, Vassiliki; Meinke, Peter; Waterfall, Martin; Kelly, David A.; Schirmer, Eric C.

    2014-01-01

    Changes in the peripheral distribution and amount of condensed chromatin are observed in a number of diseases linked to mutations in the lamin A protein of the nuclear envelope. We postulated that lamin A interactions with nuclear envelope transmembrane proteins (NETs) that affect chromatin structure might be altered in these diseases and so screened thirty-one NETs for those that promote chromatin compaction as determined by an increase in the number of chromatin clusters of high pixel intensity. One of these, NET23 (also called STING, MITA, MPYS, ERIS, Tmem173), strongly promoted chromatin compaction. A correlation between chromatin compaction and endogenous levels of NET23/STING was observed for a number of human cell lines, suggesting that NET23/STING may contribute generally to chromatin condensation. NET23/STING has separately been found to be involved in innate immune response signaling. Upon infection cells make a choice to either apoptose or to alter chromatin architecture to support focused expression of interferon genes and other response factors. We postulate that the chromatin compaction induced by NET23/STING may contribute to this choice because the cells expressing NET23/STING eventually apoptose, but the chromatin compaction effect is separate from this as the condensation was still observed when cells were treated with Z-VAD to block apoptosis. NET23/STING-induced compacted chromatin revealed changes in epigenetic marks including changes in histone methylation and acetylation. This indicates a previously uncharacterized nuclear role for NET23/STING potentially in both innate immune signaling and general chromatin architecture. PMID:25386906

  11. A mammalian cell based FACS-panning platform for the selection of HIV-1 envelopes for vaccine development.

    PubMed

    Bruun, Tim-Henrik; Mühlbauer, Katharina; Benen, Thomas; Kliche, Alexander; Wagner, Ralf

    2014-01-01

    An increasing number of broadly neutralizing monoclonal antibodies (bnMAb) against the HIV-1 envelope (Env) protein has been discovered recently. Despite this progress, vaccination efforts with the aim to re-elicit bnMAbs that provide protective immunity have failed so far. Herein, we describe the development of a mammalian cell based FACS-panning method in which bnMAbs are used as tools to select surface-exposed envelope variants according to their binding affinity. For that purpose, an HIV-1 derived lentiviral vector was developed to infect HEK293T cells at low multiplicity of infection (MOI) in order to link Env phenotype and genotype. For proof of principle, a gp145 Env model-library was established in which the complete V3 domain was substituted by five strain specific V3 loop sequences with known binding affinities to nMAb 447-52D, respectively. Env genes were recovered from selected cells by PCR, subcloned into a lentiviral vector (i) to determine and quantify the enrichment nMAb binders and (ii) to generate a new batch of transduction competent particles. After 2 selection cycles the Env variant with highest affinity was enriched 20-fold and represented 80% of the remaining Env population. Exploiting the recently described bnMAbs, this procedure might prove useful in selecting Env proteins from large Env libraries with the potential to elicit bnMAbs when used as vaccine candidates.

  12. The comparison of genetic variation in the envelope protein between various immunodeficiency viruses and equine infectious anemia virus.

    PubMed

    Yuan, Qing; Liu, Chang; Liang, Zhipin; Chen, Xueqing; Diao, Danhong; Kong, Xiaohong

    2012-08-01

    The envelope protein (Env) of lentiviruses such as HIV, SIV, FIV and EIAV is larger than that of other retroviruses. The Chinese EIAV attenuated vaccine is based on Env and has helped to successfully control this virus, demonstrating that envelope is crucial for vaccine. We compared Env variation of the four kinds of lentiviruses. Phylogenetic analysis showed that the evolutionary relationship of Env between HIV and SIV was the closest and they appeared to descend from a common ancestor, and the relationship of HIV and EIAV was the furthest. EIAV had the shortest Env length and the least number of potential N-linked glycosylation sites (PNGS) as well as glycosylation density compared to various immunodeficiency viruses. However, HIV had the longest Env length and the most PNGS. Moreover, the alignment of HIV and SIV showed that PNGS were primarily distributed within extracellular membrane protein gp120 rather than transmembrane gp41. It implies that the size difference among these viruses is associated with a lentivirus specific function and also the diversity of env. There are low levels of modification of glycosylation sites of Env and selection of optimal protective epitopes might be useful for development of an effective vaccine against HIV/AIDS.

  13. Comparison of computational methods for estimation of energy balance of building envelopes

    NASA Astrophysics Data System (ADS)

    Kočí, Václav; Černý, Robert

    2013-10-01

    Two calculation methods of annual energy balance of building envelopes are presented in this paper. As reference building envelope, single-layer autoclaved aerated concrete masonry is chosen. The first calculation method is based on simplified standard procedure, the second method on results of more sophisticated hygrothermal simulation under realistic climatic conditions. Both results are compared and analyzed.

  14. Spastin and ESCRT-III coordinate mitotic spindle disassembly and nuclear envelope sealing.

    PubMed

    Vietri, Marina; Schink, Kay O; Campsteijn, Coen; Wegner, Catherine Sem; Schultz, Sebastian W; Christ, Liliane; Thoresen, Sigrid B; Brech, Andreas; Raiborg, Camilla; Stenmark, Harald

    2015-06-11

    At the onset of metazoan cell division the nuclear envelope breaks down to enable capture of chromosomes by the microtubule-containing spindle apparatus. During anaphase, when chromosomes have separated, the nuclear envelope is reassembled around the forming daughter nuclei. How the nuclear envelope is sealed, and how this is coordinated with spindle disassembly, is largely unknown. Here we show that endosomal sorting complex required for transport (ESCRT)-III, previously found to promote membrane constriction and sealing during receptor sorting, virus budding, cytokinesis and plasma membrane repair, is transiently recruited to the reassembling nuclear envelope during late anaphase. ESCRT-III and its regulatory AAA (ATPase associated with diverse cellular activities) ATPase VPS4 are specifically recruited by the ESCRT-III-like protein CHMP7 to sites where the reforming nuclear envelope engulfs spindle microtubules. Subsequent association of another ESCRT-III-like protein, IST1, directly recruits the AAA ATPase spastin to sever microtubules. Disrupting spastin function impairs spindle disassembly and results in extended localization of ESCRT-III at the nuclear envelope. Interference with ESCRT-III functions in anaphase is accompanied by delayed microtubule disassembly, compromised nuclear integrity and the appearance of DNA damage foci in subsequent interphase. We propose that ESCRT-III, VPS4 and spastin cooperate to coordinate nuclear envelope sealing and spindle disassembly at nuclear envelope-microtubule intersection sites during mitotic exit to ensure nuclear integrity and genome safeguarding, with a striking mechanistic parallel to cytokinetic abscission.

  15. 78 FR 42820 - Agency Information Collection (Caution to Bidders-Bid Envelopes) Activities Under OMB Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-17

    ... AFFAIRS Agency Information Collection (Caution to Bidders--Bid Envelopes) Activities Under OMB Review... burden; it includes the actual data collection instrument. DATES: Comments must be submitted on or before... to Bidders--Bid Envelopes. OMB Control Number: 2900-0593. Type of Review: Revision of a...

  16. 75 FR 28859 - Agency Information Collection (Caution to Bidders-Bid Envelopes) Activities Under OMB Review

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-24

    ... AFFAIRS Agency Information Collection (Caution to Bidders--Bid Envelopes) Activities Under OMB Review... burden; it includes the actual data collection instrument. DATES: Comments must be submitted on or before...) Provision 852.214-70, Caution to Bidders--Bid Envelopes. OMB Control Number: 2900-0593. Type of...

  17. Transduction of human primitive repopulating hematopoietic cells with lentiviral vectors pseudotyped with various envelope proteins.

    PubMed

    Kim, Yoon-Sang; Wielgosz, Matthew M; Hargrove, Phillip; Kepes, Steven; Gray, John; Persons, Derek A; Nienhuis, Arthur W

    2010-07-01

    Lentiviral vectors are useful for transducing primitive hematopoietic cells. We examined four envelope proteins for their ability to mediate lentiviral transduction of mobilized human CD34(+) peripheral blood cells. Lentiviral particles encoding green fluorescent protein (GFP) were pseudotyped with the vesicular stomatitis virus envelope glycoprotein (VSV-G), the amphotropic (AMPHO) murine leukemia virus envelope protein, the endogenous feline leukemia viral envelope protein or the feline leukemia virus type C envelope protein. Because the relative amount of genome RNA per ml was similar for each pseudotype, we transduced CD34(+) cells with a fixed volume of each vector preparation. Following an overnight transduction, CD34(+) cells were transplanted into immunodeficient mice which were sacrificed 12 weeks later. The average percentages of engrafted human CD45(+) cells in total bone marrow were comparable to that of the control, mock-transduced group (37-45%). Lenti-particles pseudotyped with the VSV-G envelope protein transduced engrafting cells two- to tenfold better than particles pseudotyped with any of the gamma-retroviral envelope proteins. There was no correlation between receptor mRNA levels for the gamma-retroviral vectors and transduction efficiency of primitive hematopoietic cells. These results support the use of the VSV-G envelope protein for the development of lentiviral producer cell lines for manufacture of clinical-grade vector.

  18. 77 FR 40527 - New Express Mail Price Category-Express Mail Padded Flat Rate Envelope

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-10

    ... 111 New Express Mail Price Category--Express Mail Padded Flat Rate Envelope AGENCY: Postal Service TM... Service, Domestic Mail Manual (DMM ), to expand Express Mail product options to include a new Padded Flat... a new price category under Express Mail, Express Mail Padded Flat Rate Envelope, established by...

  19. On the mechanisms involved in the recovery of envelope information from temporal fine structure

    PubMed Central

    Apoux, Frédéric; Millman, Rebecca E.; Viemeister, Neal F.; Brown, Christopher A.; Bacon, Sid P.

    2011-01-01

    Three experiments were designed to provide psychophysical evidence for the existence of envelope information in the temporal fine structure (TFS) of stimuli that were originally amplitude modulated (AM). The original stimuli typically consisted of the sum of a sinusoidally AM tone and two unmodulated tones so that the envelope and TFS could be determined a priori. Experiment 1 showed that normal-hearing listeners not only perceive AM when presented with the Hilbert fine structure alone but AM detection thresholds are lower than those observed when presenting the original stimuli. Based on our analysis, envelope recovery resulted from the failure of the decomposition process to remove the spectral components related to the original envelope from the TFS and the introduction of spectral components related to the original envelope, suggesting that frequency- to amplitude-modulation conversion is not necessary to recover envelope information from TFS. Experiment 2 suggested that these spectral components interact in such a way that envelope fluctuations are minimized in the broadband TFS. Experiment 3 demonstrated that the modulation depth at the original carrier frequency is only slightly reduced compared to the depth of the original modulator. It also indicated that envelope recovery is not specific to the Hilbert decomposition. PMID:21786897

  20. The influence of different segments of the ongoing envelope on sensitivity to interaural time delays.

    PubMed

    Klein-Hennig, Martin; Dietz, Mathias; Hohmann, Volker; Ewert, Stephan D

    2011-06-01

    The auditory system is sensitive to interaural timing disparities in the fine structure and the envelope of sounds, each contributing important cues for lateralization. In this study, psychophysical measurements were conducted with customized envelope waveforms in order to investigate the isolated effect of different segments of a periodic, ongoing envelope on lateralization. One envelope cycle was composed of the four segments attack flank, hold duration, decay flank, and pause duration, which were independently varied to customize the envelope waveform. The envelope waveforms were applied to a 4-kHz sinusoidal carrier, and just noticeable envelope interaural time differences were measured in six normal hearing subjects. The results indicate that attack durations and pause durations prior to the attack are the most important stimulus characteristics for processing envelope timing disparities. The results were compared to predictions of three binaural lateralization models based on the normalized cross correlation coefficient. Two of the models included an additional stage to mimic neural adaptation prior to binaural interaction, involving either a single short time constant (5 ms) or a combination of five time constants up to 500 ms. It was shown that the model with the single short time constant accounted best for the data.

  1. Oral and parenteral immunization of chickens (Gallus gallus) against West Nile virus with recombinant envelope protein

    USGS Publications Warehouse

    Fassbinder-Orth, C. A.; Hofmeister, E.K.; Weeks-Levy, C.; Karasov, W.H.

    2009-01-01

    West Nile virus (WNV) causes morbidity and mortality in humans, horses, and in more than 315 bird species in North America. Currently approved WNV vaccines are designed for parenteral administration and, as yet, no effective oral WNV vaccines have been developed. WNV envelope (E) protein is a highly antigenic protein that elicits the majority of virus-neutralizing antibodies during a WNV immune response. Leghorn chickens were given three vaccinations (each 2 wk apart) of E protein orally (20 ??g or 100 ??g/dose), of E protein intramuscularly (IM, 20 ??g/dose), or of adjuvant only (control group) followed by a WNV challenge. Viremias were measured post-WNV infection, and three new enzyme-linked immunosorbent assays were developed for quantifying IgM, IgY, and IgA-mediated immune response of birds following WNV infection. WNV viremia levels were significantly lower in the IM group than in both oral groups and the control group. Total WNV E protein-specific IgY production was significantly greater, and WNV nonstructural 1-specific IgY was significantly less, in the IM group compared to all other treatment groups. The results of this study indicate that IM vaccination of chickens with E protein is protective against WNV infection and results in a significantly different antibody production profile as compared to both orally vaccinated and nonvaccinated birds. ?? 2009 American Association of Avian Pathologists.

  2. Mutation analysis of the fusion domain region of St. Louis encephalitis virus envelope protein

    SciTech Connect

    Trainor, Nicole B.; Crill, Wayne D. . E-mail: wcrill@cdc.gov; Roberson, Jill A.; Chang, Gwong-Jen J.

    2007-04-10

    The immune response to flavivirus infections produces both species-specific and flavivirus cross-reactive antibodies. The presence of cross-reactive antibodies complicates serodiagnosis of flavivirus infections, especially secondary infections caused by a heterologous virus. A successful public health response to the growing global threat posed by flaviviruses necessitates the development of virus-specific diagnostic antigens. The flavivirus envelope (E) glycoprotein is the principle antigen stimulating protective immunity during infection. Using recombinant St. Louis encephalitis virus-like particles (VLPs), we have identified amino acid residues involved in flavivirus cross-reactive epitope determinants. Most significant among the residues studied are three highly conserved amino acids in the fusion peptide: Gly104, Gly106, and Leu107. Substitutions of these residues dramatically influenced VLP secretion and cross-reactive monoclonal antibody reactivity. These results provide critical insight into the antigenic structure of the flaviviral E protein and toward development of species-specific diagnostic antigens that should improve both flavivirus diagnosis and estimates of disease burden.

  3. Maternal HIV-1 envelope-specific antibody responses and reduced risk of perinatal transmission.

    PubMed

    Permar, Sallie R; Fong, Youyi; Vandergrift, Nathan; Fouda, Genevieve G; Gilbert, Peter; Parks, Robert; Jaeger, Frederick H; Pollara, Justin; Martelli, Amanda; Liebl, Brooke E; Lloyd, Krissey; Yates, Nicole L; Overman, R Glenn; Shen, Xiaoying; Whitaker, Kaylan; Chen, Haiyan; Pritchett, Jamie; Solomon, Erika; Friberg, Emma; Marshall, Dawn J; Whitesides, John F; Gurley, Thaddeus C; Von Holle, Tarra; Martinez, David R; Cai, Fangping; Kumar, Amit; Xia, Shi-Mao; Lu, Xiaozhi; Louzao, Raul; Wilkes, Samantha; Datta, Saheli; Sarzotti-Kelsoe, Marcella; Liao, Hua-Xin; Ferrari, Guido; Alam, S Munir; Montefiori, David C; Denny, Thomas N; Moody, M Anthony; Tomaras, Georgia D; Gao, Feng; Haynes, Barton F

    2015-07-01

    Despite the wide availability of antiretroviral drugs, more than 250,000 infants are vertically infected with HIV-1 annually, emphasizing the need for additional interventions to eliminate pediatric HIV-1 infections. Here, we aimed to define humoral immune correlates of risk of mother-to-child transmission (MTCT) of HIV-1, including responses associated with protection in the RV144 vaccine trial. Eighty-three untreated, HIV-1-transmitting mothers and 165 propensity score-matched nontransmitting mothers were selected from the Women and Infants Transmission Study (WITS) of US nonbreastfeeding, HIV-1-infected mothers. In a multivariable logistic regression model, the magnitude of the maternal IgG responses specific for the third variable loop (V3) of the HIV-1 envelope was predictive of a reduced risk of MTCT. Neutralizing Ab responses against easy-to-neutralize (tier 1) HIV-1 strains also predicted a reduced risk of peripartum transmission in secondary analyses. Moreover, recombinant maternal V3-specific IgG mAbs mediated neutralization of autologous HIV-1 isolates. Thus, common V3-specific Ab responses in maternal plasma predicted a reduced risk of MTCT and mediated autologous virus neutralization, suggesting that boosting these maternal Ab responses may further reduce HIV-1 MTCT.

  4. Non-destructive inspections of illicit drugs in envelope using terahertz time-domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Li, Ning; Shen, Jingling; Lu, Meihong; Jia, Yan; Sun, Jinhai; Liang, Laishun; Shi, Yanning; Xu, Xiaoyu; Zhang, Cunlin

    2006-09-01

    The absorption spectra of two illicit drugs, methylenedioxyamphetarnine (MDA) and methamphetamine (MA), within and without two conventional envelopes are studied using terahertz time-domain spectroscopy technique. The characteristic absorption spectra of MDA and MA are obtained in the range of 0.2 THz to 2.5 THz. MDA has an obvious absorption peak at 1.41 THz while MA has obvious absorption peaks at 1.23 THz, 1.67 THz, 1.84 THz and 2.43 THz. We find that the absorption peaks of MDA and MA within the envelopes are almost the same as those without the envelopes respectively although the two envelopes have some different absorption in THz waveband. This result indicates that the type of illicit drugs in envelopes can be determined by identifying their characteristic absorption peaks, and THz time-domain spectroscopy is one of the most powerful candidates for illicit drugs inspection.

  5. Chemical alterations in cell envelopes of polymyxin-resistant Pseudomonas aeruginosa isolates.

    PubMed Central

    Gilleland, H E; Lyle, R D

    1979-01-01

    Cell envelopes from Pseudomonas aeruginosa strains resistant to polymyxin were compared with cell envelopes from polymyxin-sensitive strains as to their content of total protein, carbohydrate, and 2-keto-3-deoxyoctonate and as to their protein composition as determined by slab polyacrylamide gel electrophoresis. The cell envelopes of the polymyxin-resistant strains had reduced amounts of lipopolysaccharide, as indicated a reduction in both carbohydrate and 2-keto-3-deoxyoctonate concentrations, and a greatly altered protein composition as shown by polyacrylamide gel electrophoresis. There was a quantitative increase in total cell envelop protein in these strains. However, those protein bands identified as being major outer membrane proteins upon polyacrylamide gel electrophoresis of separated outer and cytoplasmic membranes were reduced greatly in concentration in the polymyxin-resistant cell envelopes. Thus, it appears that polymyxin resistance in these strains is associated with the alteration of the outer membrane through a loss of lipopolysaccharide and outer membrane proteins. Images PMID:222726

  6. Chemical composition and biological activity of the Yersinia pestis envelope substance.

    PubMed Central

    Głosnicka, R; Gruszkiewicz, E

    1980-01-01

    Purification of the envelope antigen of Yersinia pestis EV with passive hemagglutination activity is described. The purification procedure consisted of pancreatin digestion, chromatography on human erythrocyte stroma set on Celite, and rechromatography on Sephadex G-200. Chemical, physical, and biological properties of this antigen were investigated. The results show the lipid-polysaccharide structure of the isolated antigen. The carbohydrate moiety of the galactolipid antigen consists of galactose and fucose. The lipid fraction contained phosphatidylethanolamine and phosphatidylserine. The preparation showed high specificity in the hemagglutination reaction and in Y. pestis phage receptor activity. In two-dimensional immunoelectrophoresis, the isolated pancreatic envelope digest antigen appeared as a single line. Two-dimensional immunoelectrophoresis was modified for tandem separation and was employed to electrophoretically identify the pancreatic envelope digest, trypsin envelope digest preparation, and F1 envelope antigen of Y. pestis. Related or identical antigens showed confluence of peaks with reactions of identity. Images Fig. 8 Fig. 9 PMID:7002800

  7. Nonlinear scale separation and a renormalization interpretation in seismic envelope inversion

    NASA Astrophysics Data System (ADS)

    Luo, J.; Wu, R. S.

    2015-12-01

    Envelope inversion can nonlinearly separate the response of large-scale structure from the fine-structure. The convergence behavior of envelope inversion can be well-explained by renormalization and renormalization group (RG) theory/method. The local integration (local interaction) of the envelope operator and the local re-linearization of the envelope inversion solve the divergence problem, although it can only recover the large-scale background structure (low resolution inversion). The combined inversion of envelope inversion and waveform inversion (SEI+FWI) can substantially reduce the starting model dependence of the regular full-waveform inversion. Numerical examples from the Marmousi model and the Overthrust model are shown to demonstrate the method.

  8. Interactive buckling of an inflated envelope under mechanical and thermal loads

    NASA Astrophysics Data System (ADS)

    Wang, C. G.; Liu, M. X.; Tan, H. F.

    2017-02-01

    This paper elucidates the interactive buckling behaviors of an inflated envelope under coupled mechanical and thermal loads, especially the longitudinal wrinkling bifurcation and hoop ovalization buckling. The longitudinal bending buckling process of the inflated envelope can be divided into three continuous stages, which are global buckling, interactive global-local buckling, and kink. A variety of hoop ovalization buckling modes are observed under coupled mechanical-thermal load. Unlike the mechanical case, thermal load leads to a hoop negative ovalization buckling. In addition, it can accelerate the longitudinal coupled bifurcation and resist the hoop coupled ovalization buckling. Moreover, the bending resistance of the inflated envelope will be improved when the length of the structure is increased, resulting in the difficulty of it to become wrinkled. These results provide a new insight into the buckling behaviors of an inflated envelope under coupled external loads, and give a reference for the design of the inflated envelope.

  9. Microtubules as key coordinators of nuclear envelope and endoplasmic reticulum dynamics during mitosis.

    PubMed

    Schlaitz, Anne-Lore

    2014-07-01

    During mitosis, cells comprehensively restructure their interior to promote the faithful inheritance of DNA and cytoplasmic contents. In metazoans, this restructuring entails disassembly of the nuclear envelope, redistribution of its components into the endoplasmic reticulum (ER) and eventually nuclear envelope reassembly around the segregated chromosomes. The microtubule cytoskeleton has recently emerged as a critical regulator of mitotic nuclear envelope and ER dynamics. Microtubules and associated molecular motors tear open the nuclear envelope in prophase and remove nuclear envelope remnants from chromatin. Additionally, two distinct mechanisms of microtubule-based regulation of ER dynamics operate later in mitosis. First, association of the ER with microtubules is reduced, preventing invasion of ER into the spindle area, and second, organelle membrane is actively cleared from metaphase chromosomes. However, we are only beginning to understand the role of microtubules in shaping and distributing ER and other organelles during mitosis.

  10. Isolation and preliminary characterization of herpes simplex virus 1 primary enveloped virions from the perinuclear space.

    PubMed

    Padula, Maryn E; Sydnor, Mariam L; Wilson, Duncan W

    2009-05-01

    Herpes simplex virus 1 (HSV-1) nucleocapsids exit the nucleus by budding into the inner nuclear membrane, where they exist briefly as primary enveloped virions. These virus particles subsequently fuse their envelopes with the outer nuclear membrane, permitting nucleocapsids to then enter the cytoplasm and complete assembly. We have developed a method to isolate primary enveloped virions from HSV-1-infected cells and subjected the primary enveloped virion preparation to MALDI-MS/MS (matrix-assisted laser desorption ionization-tandem mass spectrometry) analyses. We identified most capsid proteins, a tegument protein (VP22), a glycoprotein (gD), and a cellular protein (annexin A2) in the primary enveloped virion preparation. We determined that annexin A2 does not play an essential role in infection under our experimental conditions. Elucidating the structure and biochemical properties of this unique virus assembly intermediate will provide new insights into HSV-1 biology.

  11. Quantifying envelope and fine-structure coding in auditory nerve responses to chimaeric speech.

    PubMed

    Heinz, Michael G; Swaminathan, Jayaganesh

    2009-09-01

    Any sound can be separated mathematically into a slowly varying envelope and rapidly varying fine-structure component. This property has motivated numerous perceptual studies to understand the relative importance of each component for speech and music perception. Specialized acoustic stimuli, such as auditory chimaeras with the envelope of one sound and fine structure of another have been used to separate the perceptual roles for envelope and fine structure. Cochlear narrowband filtering limits the ability to isolate fine structure from envelope; however, envelope recovery from fine structure has been difficult to evaluate physiologically. To evaluate envelope recovery at the output of the cochlea, neural cross-correlation coefficients were developed that quantify the similarity between two sets of spike-train responses. Shuffled auto- and cross-correlogram analyses were used to compute separate correlations for responses to envelope and fine structure based on both model and recorded spike trains from auditory nerve fibers. Previous correlogram analyses were extended to isolate envelope coding more effectively in auditory nerve fibers with low center frequencies, which are particularly important for speech coding. Recovered speech envelopes were present in both model and recorded responses to one- and 16-band speech fine-structure chimaeras and were significantly greater for the one-band case, consistent with perceptual studies. Model predictions suggest that cochlear recovered envelopes are reduced following sensorineural hearing loss due to broadened tuning associated with outer-hair cell dysfunction. In addition to the within-fiber cross-stimulus cases considered here, these neural cross-correlation coefficients can also be used to evaluate spatiotemporal coding by applying them to cross-fiber within-stimulus conditions. Thus, these neural metrics can be used to quantitatively evaluate a wide range of perceptually significant temporal coding issues relevant to

  12. Trace Element Condensation in Circumstellar Envelopes of Carbon Stars

    NASA Astrophysics Data System (ADS)

    Lodders, K.; Fegley, B., Jr.

    1992-07-01

    It is now well established that meteorites contain reduced presolar grains, such as graphite and silicon carbide (SiC), which are probably formed by condensation of dust in the circumstellar envelopes of carbon-rich AGB stars. Here we model condensation in envelopes of carbon stars, with an emphasis on trace elements. Since absolute elemental abundances in stellar atmospheres are generally not known, we assume solar abundances (Anders and Grevesse 1989), except for carbon. A C/O ratio of 2, consistent with the mean and median values of 2.1 and 1.8 respectively, for 61 carbon stars (Gow 1977) was used. The C/O ratio was increased by adding carbon because astrophysicists believe that carbon produced in helium-burning zones may be mixed to the surfaces of C stars (e.g. Lucy 1976). We used physical parameters for the circumstellar shell of the high mass-loss rate, prototypical carbon star IRC +10216 (e.g. Keady et al. 1988, Dominik et al. 1990) and theoretical considerations by Salpeter (1974a,b) to construct a P-T-model of the envelope (see Fig. 1). Thermodynamic equilibrium condensation calculations for a reduced gas include ~600 gaseous and solid compounds of the elements H, C, N, O, S, P, F, Cl, Fe, Mg, Al, Ti, Si, Ca, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and REE. Refractory oxides, sulfides, nitrides, and carbides were considered as condensates. The calculations were done from T = 800 to 2500 K, and P= 10^-5 to 10^-13 bars. The effects of nucleation on condensation temperatures were calculated using the nucleation model discussed by Salpeter (1974a,b) and Cameron and Fegley (1982). The temperature drop required for condensation depends on (P,T, density) in the expanding envelope and also on the abundance, density, and surface energy (Es) of the nucleating compound. The range of E(sub)s values for NaCl-type carbides are about 800-1700 erg/cm^2 (Livey & Murray 1956); however, these data are generally poorly known. Another important variable is the sticking coefficient (s

  13. Glycosylation Benchmark Profile for HIV-1 Envelope Glycoprotein Production Based on Eleven Env Trimers.

    PubMed

    Go, Eden P; Ding, Haitao; Zhang, Shijian; Ringe, Rajesh P; Nicely, Nathan; Hua, David; Steinbock, Robert T; Golabek, Michael; Alin, James; Alam, S Munir; Cupo, Albert; Haynes, Barton F; Kappes, John C; Moore, John P; Sodroski, Joseph G; Desaire, Heather

    2017-05-01

    HIV-1 envelope glycoprotein (Env) glycosylation is important because individual glycans are components of multiple broadly neutralizing antibody epitopes, while shielding other sites that might otherwise be immunogenic. The glycosylation on Env is influenced by a variety of factors, including the genotype of the protein, the cell line used for its expression, and the details of the construct design. Here, we used a mass spectrometry (MS)-based approach to map the complete glycosylation profile at every site in multiple HIV-1 Env trimers, accomplishing two goals. (i) We determined which glycosylation sites contain conserved glycan profiles across many trimeric Envs. (ii) We identified the variables that impact Env's glycosylation profile at sites with divergent glycosylation. Over half of the gp120 glycosylation sites on 11 different trimeric Envs have a conserved glycan profile, indicating that a native consensus glycosylation profile does indeed exist among trimers. We showed that some soluble gp120s and gp140s exhibit highly divergent glycosylation profiles compared to trimeric Env. We also assessed the impact of several variables on Env glycosylation: truncating the full-length Env; producing Env, instead of the more virologically relevant T lymphocytes, in CHO cells; and purifying Env with different chromatographic platforms, including nickel-nitrilotriacetic acid (Ni-NTA), 2G12, and PGT151 affinity. This report provides the first consensus glycosylation profile of Env trimers, which should serve as a useful benchmark for HIV-1 vaccine developers. This report also defines the sites where glycosylation may be impacted when Env trimers are truncated or produced in CHO cells.IMPORTANCE A protective HIV-1 vaccine will likely include a recombinant version of the viral envelope glycoprotein (Env). Env is highly glycosylated, and yet vaccine developers have lacked guidance on how to assess whether their immunogens have optimal glycosylation. The following important

  14. Memory protection

    NASA Technical Reports Server (NTRS)

    Denning, Peter J.

    1988-01-01

    Accidental overwriting of files or of memory regions belonging to other programs, browsing of personal files by superusers, Trojan horses, and viruses are examples of breakdowns in workstations and personal computers that would be significantly reduced by memory protection. Memory protection is the capability of an operating system and supporting hardware to delimit segments of memory, to control whether segments can be read from or written into, and to confine accesses of a program to its segments alone. The absence of memory protection in many operating systems today is the result of a bias toward a narrow definition of performance as maximum instruction-execution rate. A broader definition, including the time to get the job done, makes clear that cost of recovery from memory interference errors reduces expected performance. The mechanisms of memory protection are well understood, powerful, efficient, and elegant. They add to performance in the broad sense without reducing instruction execution rate.

  15. Protective Eyewear

    MedlinePlus

    ... David Turbert Reviewed by: Brenda Pagan-Duran MD Mar. 01, 2016 Eye protection means more than just ... after cataract surgery? Aug 30, 2015 Scleritis Symptoms Mar 01, 2015 Anti-reflective Coating Feb 27, 2015 ...

  16. Corrosion protection

    DOEpatents

    Brown, Donald W.; Wagh, Arun S.

    2003-05-27

    There has been invented a chemically bonded phosphate corrosion protection material and process for application of the corrosion protection material for corrosion prevention. A slurry of iron oxide and phosphoric acid is used to contact a warm surface of iron, steel or other metal to be treated. In the presence of ferrous ions from the iron, steel or other metal, the slurry reacts to form iron phosphates which form grains chemically bonded onto the surface of the steel.

  17. Interaction of Zika Virus Envelope Protein with Glycosaminoglycans.

    PubMed

    Kim, So Young; Zhao, Jing; Liu, Xinyue; Fraser, Keith; Lin, Lei; Zhang, Xing; Zhang, Fuming; Dordick, Jonathan S; Linhardt, Robert J

    2017-02-28

    In February 2016, the World Health Organization declared a Public Health Emergency of International Concern on Zika Virus (ZIKV), because of its association with severe fetal anomalies of congenitally infected humans. This has led to urgent efforts by academic, federal, and industry research groups to improve our understanding of the pathogenesis of ZIKV and to develop detection methods, therapeutic strategies, and vaccines. Although we still do not have the entire picture of the pathogenesis of ZIKV, extensive research has been conducted on related pathogenic flaviviruses (i.e., dengue virus, West Nile virus, and yellow fever virus). Binding to glycosaminoglycans (GAGs) through its envelope protein is the first step in successful host cell invasion of dengue virus. In this study, we examined ZIKV envelope protein (ZIKV E) binding to GAGs in a real time interaction study using surface plasmon resonance (SPR) to explore the role of GAGs in host cell entry of ZIKV into placenta and brain. ZIKV E strongly binds (KD = 443 nM) pharmaceutical heparin (HP), a highly sulfated GAG, and binds with lower avidity to less sulfated GAGs, suggesting that the ZIKV E-GAG interaction may be electrostatically driven. Using SPR competition assays with various chain length HP oligosaccharides (from 4 to 18 saccharide units in length), we observed that ZIKV E preferentially binds to longer HP oligosaccharides (with 8-18 saccharides). Next, we examined GAGs prepared from human placentas to determine if they bound ZIKV E, possibly mediating placental cell invasion of ZIKV. Compositional analysis of these GAGs as well as SPR binding studies showed that both chondroitin sulfate and heparan sulfate GAGs, present on the placenta, showed low-micromolar interactions with ZIKV E. Both porcine brain CS and HS also showed micromolar binding with ZIKV E. Moreover, heparan sulfate with a higher TriS content, the dominant repeating unit of HP, shows a high affinity for ZIKV E. These results suggest

  18. Extendable chord rotors for helicopter performance improvement and envelope expansion

    NASA Astrophysics Data System (ADS)

    Khoshlahjeh, Maryam

    A helicopter with a fixed geometry rotor, operating at a fixed rotational speed, performs sub-optimally over the vehicle’s flight envelope. On the other hand, if the rotor geometry and RPM can be varied from one flight condition to another, the aircraft performance can be substantially improved over the operating envelope. The geometry change considered in this study is the variation of rotor chord over a spanwise section of the blade. Simulations are based on a UH-60A Blackhawk helicopter with an effective chord increase of 20% realized by extending a Trailing-Edge Plate (TEP) through a slit in the trailing-edge between 63-83% blade span. Rigid and elastic blade models are studied. Since TEP extension changes the baseline SC-1094R8 airfoil profile, 2D aerodynamic coefficients of the modified profile from Navier-Stokes CFD calculations are used, coupled with 12x12 dynamic inflow and Leishman-Beddoes dynamic stall model in the Rotorcraft Comprehensive Analysis System (RCAS). From the simulations, reductions of up to nearly 18% in rotor power requirement are observed for operation at high gross weight and altitude. Further, increases of around 18 kts in maximum speed, 1,500 lbs in maximum gross weight capability, and 1,800 ft in maximum altitude are observed. Moreover, maneuvering flights can benefit from an extended chord. Required power for a steady level turn could be reduced nearly 7% at the maximum turn rate. Vibratory loads also reduce with TEP. Hub vertical shear, in-plane shear, and in-plane moment 4/rev component are reduced up to 47%, 29.6% and 51%, respectively, in a stall dominant condition. Furthermore, rotor speed variations of ±15% nominal RPM are considered in combination with TEP. Rotor speed reduction alone is most beneficial during low and light flight conditions. However, increasing rotor speed to 105% nominal RPM along with TEP offers additional 2,000 lbs payload capability, 5,000 ft gain in maximum altitude and up to 60 kts increase in

  19. Achieving Potent Autologous Neutralizing Antibody Responses against Tier 2 HIV-1 Viruses by Strategic Selection of Envelope Immunogens.

    PubMed

    Hessell, Ann J; Malherbe, Delphine C; Pissani, Franco; McBurney, Sean; Krebs, Shelly J; Gomes, Michelle; Pandey, Shilpi; Sutton, William F; Burwitz, Benjamin J; Gray, Matthew; Robins, Harlan; Park, Byung S; Sacha, Jonah B; LaBranche, Celia C; Fuller, Deborah H; Montefiori, David C; Stamatatos, Leonidas; Sather, D Noah; Haigwood, Nancy L

    2016-04-01

    Advancement in immunogen selection and vaccine design that will rapidly elicit a protective Ab response is considered critical for HIV vaccine protective efficacy. Vaccine-elicited Ab responses must therefore have the capacity to prevent infection by neutralization-resistant phenotypes of transmitted/founder (T/F) viruses that establish infection in humans. Most vaccine candidates to date have been ineffective at generating Abs that neutralize T/F or early variants. In this study, we report that coimmunizing rhesus macaques with HIV-1 gp160 DNA and gp140 trimeric protein selected from native envelope gene sequences (envs) induced neutralizing Abs against Tier 2 autologous viruses expressing cognate envelope (Env). The Env immunogens were selected from envs emerging during the earliest stages of neutralization breadth developing within the first 2 years of infection in two clade B-infected human subjects. Moreover, the IgG responses in macaques emulated the targeting to specific regions of Env known to be associated with autologous and heterologous neutralizing Abs developed within the human subjects. Furthermore, we measured increasing affinity of macaque polyclonal IgG responses over the course of the immunization regimen that correlated with Tier 1 neutralization. In addition, we report firm correlations between Tier 2 autologous neutralization and Tier 1 heterologous neutralization, as well as overall TZM-bl breadth scores. Additionally, the activation of Env-specific follicular helper CD4 T cells in lymphocytes isolated from inguinal lymph nodes of vaccinated macaques correlated with Tier 2 autologous neutralization. These results demonstrate the potential for native Env derived from subjects at the time of neutralization broadening as effective HIV vaccine elements.

  20. Achieving Potent Autologous Neutralizing Antibody Responses against Tier 2 HIV-1 Viruses by Strategic Selection of Envelope Immunogens

    PubMed Central

    Hessell, Ann J.; Malherbe, Delphine C.; Pissani, Franco; McBurney, Sean; Krebs, Shelly J.; Gomes, Michelle; Pandey, Shilpi; Sutton, William F.; Burwitz, Benjamin J.; Gray, Matthew; Robins, Harlan; Park, Byung S.; Sacha, Jonah B.; LaBranche, Celia C.; Fuller, Deborah H.; Montefiori, David C.; Stamatatos, Leonidas; Sather, D. Noah

    2016-01-01

    Advancement in immunogen selection and vaccine design that will rapidly elicit a protective Ab response is considered critical for HIV vaccine protective efficacy. Vaccine-elicited Ab responses must therefore have the capacity to prevent infection by neutralization-resistant phenotypes of transmitted/founder (T/F) viruses that establish infection in humans. Most vaccine candidates to date have been ineffective at generating Abs that neutralize T/F or early variants. In this study, we report that coimmunizing rhesus macaques with HIV-1 gp160 DNA and gp140 trimeric protein selected from native envelope gene sequences (envs) induced neutralizing Abs against Tier 2 autologous viruses expressing cognate envelope (Env). The Env immunogens were selected from envs emerging during the earliest stages of neutralization breadth developing within the first 2 years of infection in two clade B–infected human subjects. Moreover, the IgG responses in macaques emulated the targeting to specific regions of Env known to be associated with autologous and heterologous neutralizing Abs developed within the human subjects. Furthermore, we measured increasing affinity of macaque polyclonal IgG responses over the course of the immunization regimen that correlated with Tier 1 neutralization. In addition, we report firm correlations between Tier 2 autologous neutralization and Tier 1 heterologous neutralization, as well as overall TZM-bl breadth scores. Additionally, the activation of Env-specific follicular helper CD4 T cells in lymphocytes isolated from inguinal lymph nodes of vaccinated macaques correlated with Tier 2 autologous neutralization. These results demonstrate the potential for native Env derived from subjects at the time of neutralization broadening as effective HIV vaccine elements. PMID:26944928

  1. The Role of Amplitude Envelope in Lexical Tone Perception: Evidence from Cantonese Lexical Tone Discrimination in Adults with Normal Hearing

    ERIC Educational Resources Information Center

    Zhou, Yining Victor

    2012-01-01

    Previously published studies on the role of amplitude envelope in lexical tone perception focused on Mandarin only. Amplitude envelope was found to co-vary with fundamental frequency in Mandarin lexical tones, and amplitude envelope alone could cue tone perception in Mandarin which uses primarily tone contour for phonemic tonal contrasts. The…

  2. Development and use of chlorotetracycline fluorescence as a measurement assay of chloroplast envelope-bound mg.

    PubMed

    Gupta, A S; Berkowitz, G A

    1989-03-01

    Experiments were conducted to develop chlorotetracycline (CTC) fluorescence as an assay of Mg(2+) bound to the envelope of the intact chloroplast. This assay technique has been widely used to measure envelope associated divalent cations in animal cell and subcellular systems, but has not been used with chloroplasts. Chloroplast envelope-associated Mg(2+) was altered by pretreatment with Mg(2+) and divalent cation chelating agents and by additions of Mg(2+) to the CTC assay medium. Results indicated that for a given chloroplast preparation, relative changes in envelope-associated Mg(2+) can be effectively monitored with CTC fluorescence. It was concluded that the limitations of this assay system are: (a) chlorophyll strongly quenches CTC fluorescence signal, so a constant chlorophyll concentration must be maintained, (b) measurements must be made quickly, and (c) use of the technique to compare different chloroplast preparations may not be valid. Studies with (28)Mg(2+) confirmed our interpretation of the fluorescence results, and also suggested that the chloroplast envelope is fairly impermeable to Mg(2+). It was concluded that changes in Mg(2+) associated with the chloroplast due to incubation of plastids in solutions containing up to 5 millimolar Mg(2+) may be exclusively due to increased envelope-associated Mg(2+). The CTC assay was used in experiments to demonstrate that increases in chloroplast envelope-associated Mg(2+) inhibit photosynthetic capacity. This inhibition can be partially overcome by the presence of K(+) in the photosynthetic reaction media.

  3. Seasonal benefits of a natural propolis envelope to honey bee immunity and colony health.

    PubMed

    Borba, Renata S; Klyczek, Karen K; Mogen, Kim L; Spivak, Marla

    2015-11-01

    Honey bees, as social insects, rely on collective behavioral defenses that produce a colony-level immune phenotype, or social immunity, which in turn impacts the immune response of individuals. One behavioral defense is the collection and deposition of antimicrobial plant resins, or propolis, in the nest. We tested the effect of a naturally constructed propolis envelope within standard beekeeping equipment on the pathogen and parasite load of large field colonies, and on immune system activity, virus and storage protein levels of individual bees over the course of a year. The main effect of the propolis envelope was a decreased and more uniform baseline expression of immune genes in bees during summer and autumn months each year, compared with the immune activity in bees with no propolis envelope in the colony. The most important function of the propolis envelope may be to modulate costly immune system activity. As no differences were found in levels of bacteria, pathogens and parasites between the treatment groups, the propolis envelope may act directly on the immune system, reducing the bees' need to activate the physiologically costly production of humoral immune responses. Colonies with a natural propolis envelope had increased colony strength and vitellogenin levels after surviving the winter in one of the two years of the study, despite the fact that the biological activity of the propolis diminished over the winter. A natural propolis envelope acts as an important antimicrobial layer enshrouding the colony, benefiting individual immunity and ultimately colony health.

  4. The metastable state of nucleocapsids of enveloped viruses as probed by high hydrostatic pressure.

    PubMed

    Gaspar, L P; Terezan, A F; Pinheiro, A S; Foguel, D; Rebello, M A; Silva, J L

    2001-03-09

    Enveloped viruses fuse their membranes with cellular membranes to transfer their genomes into cells at the beginning of infection. What is not clear, however, is the role of the envelope (lipid bilayer and glycoproteins) in the stability of the viral particle. To address this question, we compared the stability between enveloped and nucleocapsid particles of the alphavirus Mayaro using hydrostatic pressure and urea. The effects were monitored by intrinsic fluorescence, light scattering, and binding of fluorescent dyes, including bis(8-anilinonaphthalene-1-sulfonate) and ethidium bromide. Pressure caused a drastic dissociation of the nucleocapsids as determined by tryptophan fluorescence, light scattering, and gel filtration chromatography. Pressure-induced dissociation of the nucleocapsids was poorly reversible. In contrast, when the envelope was present, pressure effects were much less marked and were highly reversible. Binding of ethidium bromide occurred when nucleocapsids were dissociated under pressure, indicating exposure of the nucleic acid, whereas enveloped particles underwent no changes. Overall, our results demonstrate that removal of the envelope with the glycoproteins leads the particle to a metastable state and, during infection, may serve as the trigger for disassembly and delivery of the genome. The envelope acts as a "Trojan horse," gaining entry into the host cell to allow release of a metastable nucleocapsid prone to disassembly.

  5. Millimeter-sized grains in the protostellar envelopes: Where do they come from?

    NASA Astrophysics Data System (ADS)

    Wong, Yi Hang Valerie; Hirashita, Hiroyuki; Li, Zhi-Yun

    2016-08-01

    Grain growth during star formation affects the physical and chemical processes in the evolution of star-forming clouds. We investigate the origin of the millimeter (mm)-sized grains recently observed in Class I protostellar envelopes. We use the coagulation model developed in our previous paper and find that a hydrogen number density of as high as 1010 cm-3, instead of the typical density 105 cm-3, is necessary for the formation of mm-sized grains. Thus, we test a hypothesis that such large grains are transported to the envelope from the inner, denser parts, finding that gas drag by outflow efficiently "launches" the large grains as long as the central object has not grown to ≳0.1 M⊙. By investigating the shattering effect on the mm-sized grains, we ensure that the large grains are not significantly fragmented after being injected in the envelope. We conclude that the mm-sized grains observed in the protostellar envelopes are not formed in the envelopes but formed in the inner parts of the star-forming regions and transported to the envelopes before a significant mass growth of the central object, and that they survive in the envelopes.

  6. Low-mass gas envelopes around accreting cores embedded in radiative 3D discs

    NASA Astrophysics Data System (ADS)

    Lega, Elena; Lambrechts, Michiel

    2016-10-01

    Planets with a core mass larger than few Earth masses and a gaseous envelope not exceeding about 10% of the total mass budget are common. Such planets are present in the Solar System (Uranus, Neptune) and are frequently observed around other stars.Our knowledge about the evolution of gas envelopes is mainly based on 1D models. However, such models cannot investigate the complex interaction between the forming envelope and the surrounding gas disc.In this work we perform 3D hydrodynamics simulations accounting for energy transfer and radiative cooling using the FARGOCA code (Lega et al., MNRAS 440, 2014). In addition to the usually considered heatingsources, namely viscous and compressional heating, we have modeled the energy deposited by the accretion of solids.We show that the thermal evolution of the envelope of a 5 Earth mass core is mainly dominated by compressional heating for accretion rates lower than 5 Earth masses per 105 years.Additionally, we demonstrate efficient gas circulation through the envelope. Under certain conditions, the competition between gas circulation and cooling of the envelope can efficiently delay the onset of runaway accretion. This could help in explaining the population of planets with low-mass gas envelope.

  7. Can the removal of molecular cloud envelopes by external feedback affect the efficiency of star formation?

    NASA Astrophysics Data System (ADS)

    Lucas, William E.; Bonnell, Ian A.; Forgan, Duncan H.

    2017-01-01

    We investigate how star formation efficiency can be significantly decreased by the removal of a molecular cloud's envelope by feedback from an external source. Feedback from star formation has difficulties halting the process in dense gas but can easily remove the less dense and warmer envelopes where star formation does not occur. However, the envelopes can play an important role keeping their host clouds bound by deepening the gravitational potential and providing a constraining pressure boundary. We use numerical simulations to show that removal of the cloud envelopes results in all cases in a fall in the star formation efficiency (SFE). At 1.38 free-fall times our 4 pc cloud simulation experienced a drop in the SFE from 16 to six percent, while our 5 pc cloud fell from 27 to 16 per cent. At the same time, our 3 pc cloud (the least bound) fell from an SFE of 5.67 per cent to zero when the envelope was lost. The star formation efficiency per free-fall time varied from zero to ≈0.25 according to α, defined to be the ratio of the kinetic plus thermal to gravitational energy, and irrespective of the absolute star forming mass available. Furthermore the fall in SFE associated with the loss of the envelope is found to even occur at later times. We conclude that the SFE will always fall should a star forming cloud lose its envelope due to stellar feedback, with less bound clouds suffering the greatest decrease.

  8. Respiratory syncytial virus envelope glycoprotein (G) has a novel structure.

    PubMed Central

    Satake, M; Coligan, J E; Elango, N; Norrby, E; Venkatesan, S

    1985-01-01

    Amino acid sequence of human respiratory syncytial virus envelope glycoprotein (G) was deduced from the DNA sequence of a recombinant plasmid and confirmed by limited amino acid microsequencing of purified 90K G protein. The calculated molecular mass of the protein encoded by the only long open reading frame of 298 amino acids was 32,588 daltons and was somewhat smaller than the 36K polypeptide translated in vitro from mRNA selected by this plasmid. Inspection of the sequence revealed a single hydrophobic domain of 23 amino acids capable of membrane insertion at 41 residues from the N-terminus. There was no N-terminal signal sequence and the hydrophilic N-terminal 20 residues probably represent the cytoplasmic tail of the protein. The N-terminally oriented membrane insertion was somewhat analogous to paramyxovirus hemagglutinin-neuraminidase (HN) and influenza neuraminidase (NA). The protein was moderately hydrophilic and rich in hydroxy-amino acids. It was both N- and O-glycosylated with the latter contributing significantly to the net molecular mass 90K. Images PMID:4069997

  9. Mathematical models: a key to understanding HIV envelope interactions?

    PubMed

    Magnus, Carsten; Brandenberg, Oliver F; Rusert, Peter; Trkola, Alexandra; Regoes, Roland R

    2013-12-15

    The spikes of the human immunodeficiency virus (HIV) mediate viral entry and are the most important targets for neutralizing antibodies. Each spike consists of three identical subunits. The role of the spike's subunits in antibody binding is not fully understood. One experimental approach to analyze trimer function uses assays with mixed envelope trimer expressing cells or viruses. As these experiments do not allow direct observation of subunit functions, mathematical models are required to interpret them. Here we describe a modeling framework to study (i) the interaction of the V1V2 loop with epitopes on the V3 loop and (ii) the composition of quaternary epitopes. In a first step we identify which trimers can form in these assays and how they function under antibody binding. We then derive the behavior of an average trimer. We contrast two experimental reporting systems and list their advantages and disadvantages. In these experiments trimer formation might not be perfectly random and we show how these effects can be tested. As we still lack a potent vaccine against HIV, and this vaccine surely has to stimulate the production of neutralizing antibodies, mixed trimer approaches in combination with mathematical models will help to identify vulnerable sites of the HIV spike.

  10. Assessment of Suited Reach Envelope in an Underwater Environment

    NASA Technical Reports Server (NTRS)

    Kim, Han; Benson, Elizabeth; Bernal, Yaritza; Jarvis, Sarah; Meginnis, Ian; Rajulu, Sudhakar

    2017-01-01

    Predicting the performance of a crewmember in an extravehicular activity (EVA) space suit presents unique challenges. The kinematic patterns of suited motions are difficult to reproduce in gravity. Additionally, 3-D suited kinematics have been practically and technically difficult to quantify in an underwater environment, in which crewmembers are commonly trained and assessed for performance. The goal of this study is to develop a hardware and software system to predictively evaluate the kinematic mobility of suited crewmembers, by measuring the 3-D reach envelope of the suit in an underwater environment. This work is ultimately aimed at developing quantitative metrics to compare the mobility of the existing Extravehicular Mobility Unit (EMU) to newly developed space suit, such as the Z-2. The EMU has been extensively used at NASA since 1981 for EVA outside the Space Shuttle and International Space Station. The Z-2 suit is NASA's newest prototype space suit. The suit is comprised of new upper torso and lower torso architectures, which were designed to improve test subject mobility.

  11. Nucleocytoplasmic transport of nucleocapsid proteins of enveloped RNA viruses

    PubMed Central

    Wulan, Wahyu N.; Heydet, Deborah; Walker, Erin J.; Gahan, Michelle E.; Ghildyal, Reena

    2015-01-01

    Most viruses with non-segmented single stranded RNA genomes complete their life cycle in the cytoplasm of infected cells. However, despite undergoing replication in the cytoplasm, the structural proteins of some of these RNA viruses localize to the nucleus at specific times in the virus life cycle, primarily early in infection. Limited evidence suggests that this enhances successful viral replication by interfering with or inhibiting the host antiviral response. Nucleocapsid proteins of RNA viruses have a well-established, essential cytoplasmic role in virus replication and assembly. Intriguingly, nucleocapsid proteins of some RNA viruses also localize to the nucleus/nucleolus of infected cells. Their nuclear function is less well understood although significant advances have been made in recent years. This review will focus on the nucleocapsid protein of cytoplasmic enveloped RNA viruses, including their localization to the nucleus/nucleolus and function therein. A greater understanding of the nuclear localization of nucleocapsid proteins has the potential to enhance therapeutic strategies as it can be a target for the development of live-attenuated vaccines or antiviral drugs. PMID:26082769

  12. Penicillin-binding site on the Escherichia coli cell envelope

    SciTech Connect

    Amaral, L.; Lee, Y.; Schwarz, U.; Lorian, V.

    1986-08-01

    The binding of /sup 35/S-labeled penicillin to distinct penicillin-binding proteins (PBPs) of the cell envelope obtained from the sonication of Escherichia coli was studied at different pHs ranging from 4 to 11. Experiments distinguishing the effect of pH on penicillin binding by PBP 5/6 from its effect on beta-lactamase activity indicated that although substantial binding occurred at the lowest pH, the amount of binding increased with pH, reaching a maximum at pH 10. Based on earlier studies, it is proposed that the binding at high pH involves the formation of a covalent bond between the C-7 of penicillin and free epsilon amino groups of the PBPs. At pHs ranging from 4 to 8, position 1 of penicillin, occupied by sulfur, is considered to be the site that establishes a covalent bond with the sulfhydryl groups of PBP 5. The use of specific blockers of free epsilon amino groups or sulfhydryl groups indicated that wherever the presence of each had little or no effect on the binding of penicillin by PBP 5, the presence of both completely prevented binding. The specific blocker of the hydroxyl group of serine did not affect the binding of penicillin.

  13. HIV-1 envelope glycoprotein immunogens to induce broadly neutralizing antibodies.

    PubMed

    Sliepen, Kwinten; Sanders, Rogier W

    2016-01-01

    The long pursuit for a vaccine against human immunodeficiency virus 1 (HIV-1) has recently been boosted by a number of exciting developments. An HIV-1 subunit vaccine ideally should elicit potent broadly neutralizing antibodies (bNAbs), but raising bNAbs by vaccination has proved extremely difficult because of the characteristics of the HIV-1 envelope glycoprotein complex (Env). However, the isolation of bNAbs from HIV-1-infected patients demonstrates that the human humoral immune system is capable of making such antibodies. Therefore, a focus of HIV-1 vaccinology is the elicitation of bNAbs by engineered immunogens and by using vaccination strategies aimed at mimicking the bNAb maturation pathways in HIV-infected patients. Important clues can also be taken from the successful subunit vaccines against hepatitis B virus and human papillomavirus. Here, we review the different types of HIV-1 immunogens and vaccination strategies that are being explored in the search for an HIV-1 vaccine that induces bNAbs.

  14. Asteroseismic constraints on diffusion in white dwarf envelopes

    NASA Astrophysics Data System (ADS)

    Bischoff-Kim, A.; Metcalfe, T. S.

    2011-06-01

    The asteroseismic analysis of white dwarfs allows us to peer below their photospheres and determine their internal structure. At ˜28 000 K EC20058-5234 is the hottest known pulsating helium atmosphere white dwarf. As such, it constitutes an important link in the evolution of white dwarfs down the cooling track. It is also astrophysically interesting because it is at a temperature where white dwarfs are expected to cool mainly through the emission of plasmon neutrinos. In the present work, we perform an asteroseismic analysis of EC20058-5234 and place the results in the context of stellar evolution and time-dependent diffusion calculations. We use a parallel genetic algorithm complemented with targeted grid searches to find the models that fit the observed periods best. Comparing our results with similar modelling of EC20058-5234's cooler cousin CBS114, we find a helium envelope thickness consistent with time-dependent diffusion calculations and obtain a precise mode identification for EC20058-5234.

  15. Assessing farming eco-efficiency: a Data Envelopment Analysis approach.

    PubMed

    Picazo-Tadeo, Andrés J; Gómez-Limón, José A; Reig-Martínez, Ernest

    2011-04-01

    This paper assesses farming eco-efficiency using Data Envelopment Analysis (DEA) techniques. Eco-efficiency scores at both farm and environmental pressure-specific levels are computed for a sample of Spanish farmers operating in the rain-fed agricultural system of Campos County. The determinants of eco-efficiency are then studied using truncated regression and bootstrapping techniques. We contribute to previous literature in this field of research by including information on slacks in the assessment of the potential environmental pressure reductions in a DEA framework. Our results reveal that farmers are quite eco-inefficient, with very few differences emerging among specific environmental pressures. Moreover, eco-inefficiency is closely related to technical inefficiencies in the management of inputs. Regarding the determinants of eco-efficiency, farmers benefiting from agri-environmental programs as well as those with university education are found to be more eco-efficient. Concerning the policy implications of these results, public expenditure in agricultural extension and farmer training could be of some help to promote integration between farming and the environment. Furthermore, Common Agricultural Policy agri-environmental programs are an effective policy to improve eco-efficiency, although some doubts arise regarding their cost-benefit balance.

  16. Full Flight Envelope Direct Thrust Measurement on a Supersonic Aircraft

    NASA Technical Reports Server (NTRS)

    Conners, Timothy R.; Sims, Robert L.

    1998-01-01

    Direct thrust measurement using strain gages offers advantages over analytically-based thrust calculation methods. For flight test applications, the direct measurement method typically uses a simpler sensor arrangement and minimal data processing compared to analytical techniques, which normally require costly engine modeling and multisensor arrangements throughout the engine. Conversely, direct thrust measurement has historically produced less than desirable accuracy because of difficulty in mounting and calibrating the strain gages and the inability to account for secondary forces that influence the thrust reading at the engine mounts. Consequently, the strain-gage technique has normally been used for simple engine arrangements and primarily in the subsonic speed range. This paper presents the results of a strain gage-based direct thrust-measurement technique developed by the NASA Dryden Flight Research Center and successfully applied to the full flight envelope of an F-15 aircraft powered by two F100-PW-229 turbofan engines. Measurements have been obtained at quasi-steady-state operating conditions at maximum non-augmented and maximum augmented power throughout the altitude range of the vehicle and to a maximum speed of Mach 2.0 and are compared against results from two analytically-based thrust calculation methods. The strain-gage installation and calibration processes are also described.

  17. Impact assessment and performance targets for lighting and envelope systems

    SciTech Connect

    Sullivan, R.; Lee, E.S.; Selkowitz, S.

    1992-06-01

    Electric lighting loads and cooling from solar heat gains and from lights are the two largest components of peak demand in commercial buildings. The most cost effective demand side management solutions are generally those that directly reduce or eliminate these loads. Existing technologies can provide modest reductions, however they are typically applied an a piecemeal manner that yields less than optimal results. The full potential of existing technologies will be realized when they are commercially available in an integrated package easily specifiable by architects and engineers. Emerging technologies can also be developed to provide even greater savings and extend the savings over a greater portion of the building floor area. This report assesses achievable energy and peak demand performance in California commercial buildings with technologies available today and in the future. We characterize energy performance over a large range of building envelope and lighting conditions, both through computer simulation models and through case study measured data, and subsequently determine reasonable energy targets if building design were further optimized with integrated systems of current or new technologies. Energy targets are derived from the study after consideration of industry priorities, design constraints, market forces, energy code influence, and the state of current building stock.

  18. Coronavirus envelope (E) protein remains at the site of assembly

    SciTech Connect

    Venkatagopalan, Pavithra; Daskalova, Sasha M.; Lopez, Lisa A.; Dolezal, Kelly A.; Hogue, Brenda G.

    2015-04-15

    Coronaviruses (CoVs) assemble at endoplasmic reticulum Golgi intermediate compartment (ERGIC) membranes and egress from cells in cargo vesicles. Only a few molecules of the envelope (E) protein are assembled into virions. The role of E in morphogenesis is not fully understood. The cellular localization and dynamics of mouse hepatitis CoV A59 (MHV) E protein were investigated to further understanding of its role during infection. E protein localized in the ERGIC and Golgi with the amino and carboxy termini in the lumen and cytoplasm, respectively. E protein does not traffic to the cell surface. MHV was genetically engineered with a tetracysteine tag at the carboxy end of E. Fluorescence recovery after photobleaching (FRAP) showed that E is mobile in ERGIC/Golgi membranes. Correlative light electron microscopy (CLEM) confirmed the presence of E in Golgi cisternae. The results provide strong support that E proteins carry out their function(s) at the site of budding/assembly. - Highlights: • Mouse hepatitis coronavirus (MHV-CoV) E protein localizes in the ERGIC and Golgi. • MHV-CoV E does not transport to the cell surface. • MHV-CoV can be genetically engineered with a tetracysteine tag appended to E. • First FRAP and correlative light electron microscopy of a CoV E protein. • Live-cell imaging shows that E is mobile in ERGIC/Golgi membranes.

  19. Enhanced antagonism of BST-2 by a neurovirulent SIV envelope

    PubMed Central

    Matsuda, Kenta; Chen, Chia-Yen; Whitted, Sonya; Chertova, Elena; Roser, David J.; Wu, Fan; Plishka, Ronald J.; Ourmanov, Ilnour; Buckler-White, Alicia; Lifson, Jeffrey D.; Strebel, Klaus; Hirsch, Vanessa M.

    2016-01-01

    Current antiretroviral therapy (ART) is not sufficient to completely suppress disease progression in the CNS, as indicated by the rising incidence of HIV-1–associated neurocognitive disorders (HAND) among infected individuals on ART. It is not clear why some HIV-1–infected patients develop HAND, despite effective repression of viral replication in the circulation. SIV-infected nonhuman primate models are widely used to dissect the mechanisms of viral pathogenesis in the CNS. Here, we identified 4 amino acid substitutions in the cytoplasmic tail of viral envelope glycoprotein gp41 of the neurovirulent virus SIVsm804E that enhance replication in macrophages and associate with enhanced antagonism of the host restriction factor BM stromal cell antigen 2 (BST-2). Rhesus macaques were inoculated with a variant of the parental virus SIVsmE543-3 that had been engineered to contain the 4 amino acid substitutions present in gp41 of SIVsm804E. Compared with WT virus–infected controls, animals infected with mutant virus exhibited higher viral load in cerebrospinal fluid. Together, these results are consistent with a potential role for BST-2 in the CNS microenvironment and suggest that BST-2 antagonists may serve as a possible target for countermeasures against HAND. PMID:27159392

  20. Control room envelope unfiltered air inleakage test protocols

    SciTech Connect

    Lagus, P.L.; Grot, R.A.

    1997-08-01

    In 1983, the Advisory Committee on Reactor Safeguards (ACRS) recommended that the US NRC develop a control room HVAC performance testing protocol. To date no such protocol has been forthcoming. Beginning in mid-1994, an effort was funded by NRC under a Small Business Innovation Research (SBIR) grant to develop several simplified test protocols based on the principles of tracer gas testing in order to measure the total unfiltered inleakage entering a CRE during emergency mode operation of the control room ventilation system. These would allow accurate assessment of unfiltered air inleakage as required in SRP 6.4. The continuing lack of a standard protocol is unfortunate since one of the significant parameters required to calculate operator dose is the amount of unfiltered air inleakage into the control room. Often it is assumed that, if the Control Room Envelope (CRE) is maintained at +1/8 in. w.g. differential pressure relative to the surroundings, no significant unfiltered inleakage can occur it is further assumed that inleakage due to door openings is the only source of unfiltered air. 23 refs., 13 figs., 2 tabs.

  1. Carrier-envelope-offset frequency detection of an ultrafast VECSEL

    NASA Astrophysics Data System (ADS)

    Mangold, M.; Zaugg, C. A.; Klenner, A.; Mayer, A. S.; Link, S. M.; Emaury, F.; Golling, M.; Gini, E.; Saraceno, C. J.; Tilma, B. W.; Keller, U.

    2015-03-01

    Ultrafast VECSELs with high peak power are of great interest for gigahertz frequency combs, as they provide a high power per comb-line and large comb-tooth spacing. However, the detection and stabilization of the carrier-envelope-offset frequency (fCEO) using an f-to-2f detection scheme, crucial for most frequency comb applications, requires short pulse durations around 100 fs combined with kilowatt peak power to generate a coherent octave-spanning supercontinuum. We present the detection of the fCEO beat notes from an ultrafast semiconductor laser. The laser is a SESAM-modelocked VECSEL which generates 231-fs pulses in 100-mW average output power at a repetition rate of 1.75 GHz and a wavelength of 1040 nm. As the performance of the oscillator is not sufficient for direct fCEO detection the pulses were amplified in an Yb-doped fiber amplifier and subsequently broadened by self-phase modulation in a large mode area fiber. The amplified pulses were compressed to a pulse duration of 85 fs at 2.2 W of average output power and launched into a highly nonlinear photonic crystal fiber. A coherent octave-spanning supercontinuum covering 680 nm to 1360 nm was generated, which supported for the first time fCEO detection from a femtosecond VECSEL in a standard f-to-2f interferometer.

  2. Lipid partitioning at the nuclear envelope controls membrane biogenesis

    PubMed Central

    Barbosa, Antonio Daniel; Sembongi, Hiroshi; Su, Wen-Min; Abreu, Susana; Reggiori, Fulvio; Carman, George M.; Siniossoglou, Symeon

    2015-01-01

    Partitioning of lipid precursors between membranes and storage is crucial for cell growth, and its disruption underlies pathologies such as cancer, obesity, and type 2 diabetes. However, the mechanisms and signals that regulate this process are largely unknown. In yeast, lipid precursors are mainly used for phospholipid synthesis in nutrient-rich conditions in order to sustain rapid proliferation but are redirected to triacylglycerol (TAG) stored in lipid droplets during starvation. Here we investigate how cells reprogram lipid metabolism in the endoplasmic reticulum. We show that the conserved phosphatidate (PA) phosphatase Pah1, which generates diacylglycerol from PA, targets a nuclear membrane subdomain that is in contact with growing lipid droplets and mediates TAG synthesis. We find that cytosol acidification activates the master regulator of Pah1, the Nem1-Spo7 complex, thus linking Pah1 activity to cellular metabolic status. In the absence of TAG storage capacity, Pah1 still binds the nuclear membrane, but lipid precursors are redirected toward phospholipids, resulting in nuclear deformation and a proliferation of endoplasmic reticulum membrane. We propose that, in response to growth signals, activation of Pah1 at the nuclear envelope acts as a switch to control the balance between membrane biogenesis and lipid storage. PMID:26269581

  3. Sporulation, bacterial cell envelopes and the origin of life

    PubMed Central

    Tocheva, Elitza I.; Ortega, Davi R.; Jensen, Grant J.

    2016-01-01

    Electron cryotomography (ECT) enables the 3D reconstruction of intact cells in a near-native state. Images produced by ECT have led to the proposal that an ancient sporulation-like event gave rise to the second membrane in diderm bacteria. Tomograms of sporulating monoderm and diderm bacterial cells show how sporulation can lead to the generation of diderm cells. Tomograms of Gram-negative and Gram-positive cell walls and purified sacculi suggest that they are more closely related than previously thought and support the hypothesis that they share a common origin. Mapping the distribution of cell envelope architectures onto a recent phylogenetic tree of life indicates that the diderm cell plan, and therefore the sporulation-like event that gave rise to it, must be very ancient. One explanation for this model is that during the cataclysmic transitions of the early Earth, cellular evolution may have gone through a bottleneck in which only spores survived, which implies that the last bacterial common ancestor was a spore. PMID:28232669

  4. ACCEPTABILITY ENVELOPE FOR METAL HYDRIDE-BASED HYDROGEN STORAGE SYSTEMS

    SciTech Connect

    Hardy, B.; Corgnale, C.; Tamburello, D.; Garrison, S.; Anton, D.

    2011-07-18

    The design and evaluation of media based hydrogen storage systems requires the use of detailed numerical models and experimental studies, with significant amount of time and monetary investment. Thus a scoping tool, referred to as the Acceptability Envelope, was developed to screen preliminary candidate media and storage vessel designs, identifying the range of chemical, physical and geometrical parameters for the coupled media and storage vessel system that allow it to meet performance targets. The model which underpins the analysis allows simplifying the storage system, thus resulting in one input-one output scheme, by grouping of selected quantities. Two cases have been analyzed and results are presented here. In the first application the DOE technical targets (Year 2010, Year 2015 and Ultimate) are used to determine the range of parameters required for the metal hydride media and storage vessel. In the second case the most promising metal hydrides available are compared, highlighting the potential of storage systems, utilizing them, to achieve 40% of the 2010 DOE technical target. Results show that systems based on Li-Mg media have the best potential to attain these performance targets.

  5. Measuring the efficiency of wastewater services through Data Envelopment Analysis.

    PubMed

    Guerrini, A; Romano, G; Leardini, C; Martini, M

    2015-01-01

    Efficient water management is a priority in the European Union, since the operational efficiency of many water utilities is very low compared to best practice. Several countries are restructuring the water industry to save costs. Larger-scale operations and vertical integration are promoted to achieve scale and scope economies; however, the literature is not unanimous that such economies exist. There is also little evidence of the effect of customer density on costs. This article offers some insights into this matter, analysing the Danish water industry by a two-stage Data Envelopment Analysis approach to investigate the effects of size, scope and density in the wastewater industry. The results show that the Danish wastewater industry is positively affected by vertical integration and higher population density: firms that serve more than 100 person per km of sewer and combine water and wastewater services achieve better efficiency. Size does not have any significant influence on global efficiency, although technical pure efficiency decreases statistically with firm size.

  6. Structural constraints determine the glycosylation of HIV-1 envelope trimers

    PubMed Central

    Pritchard, Laura K.; Vasiljevic, Snezana; Ozorowski, Gabriel; Seabright, Gemma E.; Cupo, Albert; Ringe, Rajesh; Kim, Helen J.; Sanders, Rogier W.; Doores, Katie J.; Burton, Dennis R.; Wilson, Ian A.; Ward, Andrew B.; Moore, John P.; Crispin, Max

    2015-01-01

    A highly glycosylated, trimeric envelope glycoprotein (Env) mediates HIV-1 cell entry. The high density and heterogeneity of the glycans shield Env from recognition by the immune system but, paradoxically, many potent broadly neutralizing antibodies (bNAbs) recognize epitopes involving this glycan shield. To better understand Env glycosylation and its role in bNAb recognition, we characterized a soluble, cleaved recombinant trimer (BG505 SOSIP.664) that is a close structural and antigenic mimic of native Env. Large, unprocessed oligomannose-type structures (Man8-9GlcNAc2) are notably prevalent on the gp120 components of the trimer, irrespective of the mammalian cell expression system or the bNAb used for affinity-purification. In contrast, gp41 subunits carry more highly processed glycans. The glycans on uncleaved, non-native oligomeric gp140 proteins are also highly processed. A homogeneous, oligomannose-dominated glycan profile is therefore a hallmark of a native Env conformation and a potential Achilles’ heel that can be exploited for bNAb recognition and vaccine design. PMID:26051934

  7. Synthesis of cell envelope glycoproteins of Cryptococcus laurentii

    PubMed Central

    Schutzbach, John; Ankel, Helmut; Brockhausen, Inka

    2007-01-01

    Fungi of the genus Cryptococcus are encapsulated basidiomycetes that are ubiquitously found in the environment. These organisms infect both lower and higher animals. Human infections that are common in immune-compromised individuals have proven difficult to cure or even control with currently available antimycotics that are quite often toxic to the host. The virulence of Cryptococcus has been linked primarily to its polysaccharide capsule, but also to cell-bound glycoproteins. In this review we show that C. laurentii is an excellent model for studies of polysaccharide and glycoprotein synthesis in the pathogenic relative C. neoformans. In particular we will discuss the structure and biosynthesis of O-linked carbohydrates on cell envelope glycoproteins of C. laurentii. These O-linked structures are synthesized by at least four mannosyltransferases, two galactosyltransferases and at least one xylosyltransferase that have been characterized. These glycosyltransferases have no known homologues in human tissues. Therefore enzymes involved in the synthesis of cryptococcal glycoproteins, as well as related enzymes involved in capsule synthesis, are potential targets for the development of specific inhibitors for treatment of cryptococcal disease. PMID:17316583

  8. Mechanism of Dissolution of Envelopes of the Extreme Halophile Halobacterium cutirubrum1

    PubMed Central

    Onishi, H.; Kushner, D. J.

    1966-01-01

    Onishi, H. (National Research Council, Ottawa, Ontario, Canada), and D. J. Kushner. Mechanism of dissolution of envelopes of the extreme halophile Halobacterium cutirubrum. J. Bacteriol. 91:646–652. 1966.—Envelopes of Halobacterium cutirubrum dissolved rapidly in media of low ionic strength. Heating partially inhibited breakdown, probably because of nonspecific protein coagulation rather than inactivation of a lytic enzyme(s). Dissolution of envelopes in water did not involve splitting of peptide bonds or protein-lipid bonds, or any extensive breakdown of carbohydrate polymers. Dissolution was increased by alcohols and urea, even at high salt concentrations, but was not affected by metabolic inhibitors. Thus, no evidence was found for a dilution-activated lytic enzyme that contributes to envelope breakdown. Cells of H. cutirubrum were stable in 2 m NaCl, but lysis occurred in 2 m KCl or NH4Cl. This lysis did not involve an extensive breakdown of the envelope. No evidence for different sites of Na+, K+, and NH4+ action was obtained from the pattern of release of envelope constituents in different concentrations of these salts. Ultracentrifugation studies showed that adding salts to envelopes that had been dissolved in water led to a nonspecific reaggregation of envelope material. No difference was seen between the effects of KCl and NaCl, except at 3 to 4 m concentrations where KCl caused more aggregation. The preferential effect of Na+ on intact cells is probably due to its ability specifically to prevent leakage rather than to an overall effect on envelope integrity. Images PMID:5883109

  9. Envelope, phase, and frequency of ultrabroadband signal in a transparent medium

    SciTech Connect

    Shpolyanskiy, Yu. A.

    2010-10-15

    Analytical signal formalism is used for derivation of expressions for a complex envelope of radiation with ultrabroadband spectrum and an arbitrary waveform, which occur rarely in modern texts on nonlinear optics. It is demonstrated that the envelope, phase, and instantaneous frequency of femtosecond radiation pulses with an ultrabroad spectrum in a transparent medium can exhibit oscillations with a characteristic time scale considerably shorter than one field cycle at the central frequency. The interference of pulses and the generation of multiple frequencies are among phenomena giving rise to such features. It is marked that the violation of conditions imposed by the theory of analytical signal leads to ambiguity of the complex envelope.

  10. Deformations of non-compact complex curves and envelopes of meromorphy of spheres

    SciTech Connect

    Ivashkovich, S M; Shevchishin, V V

    1998-10-31

    The paper discusses the properties of the envelopes of meromorphy of neighbourhoods of symplectically immersed two-spheres in complex Kahler surfaces. The method used to study the envelopes of meromorphy is based on Gromov's theory of pseudoholomorphic curves. The exposition includes a construction of a complete family of holomorphic deformations of a non-compact complex curve in a complex manifold parametrized by a finite-codimensional analytic subset of a Banach ball. The existence of this family is used to prove a generalization of Levi's continuity principle, which is applied to describe envelopes of meromorphy.

  11. Six-month-old infants discriminate voicing on the basis of temporal envelope cues (L).

    PubMed

    Bertoncini, Josiane; Nazzi, Thierry; Cabrera, Laurianne; Lorenzi, Christian

    2011-05-01

    Young deaf children using a cochlear implant develop speech abilities on the basis of speech temporal-envelope signals distributed over a limited number of frequency bands. A Headturn Preference Procedure was used to measure looking times in 6-month-old, normal-hearing infants during presentation of repeating or alternating sequences composed of different tokens of /aba/and /apa/ processed to retain envelope information below 64 Hz while degrading temporal fine structure cues. Infants attended longer to the alternating sequences, indicating that they perceive the voicing contrast on the basis of envelope cues alone in the absence of fine spectral and temporal structure information.

  12. Noise Protection

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Environmental Health Systems puts forth an increasing effort in the U.S. to develop ways of controlling noise, particularly in industrial environments due to Federal and State laws, labor union insistence and new findings relative to noise pollution impact on human health. NASA's Apollo guidance control system aided in the development of a noise protection product, SMART. The basis of all SMART products is SMART compound a liquid plastic mixture with exceptional energy/sound absorbing qualities. The basic compound was later refined for noise protection use.

  13. Structures protection

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Materials of which an aircraft is made and the methods used to hold these materials together forming the aircraft structure were studied as factors important in protecting a modern aircraft from hazardous natural environments. Since all-metal aircraft are being replaced by aircraft constructed partly of fiber reinforced plastics with desirable light weight and high strength properties but with poor electrical conductivity, the danger of lightning strikes has become more serious. Lightning effects on metal structures were reviewed and design protection was discussed. The expected lightning effects on nonmetallic materials such as fiberglass and advanced composites were also reviewed.

  14. Ozone Layer Protection

    MedlinePlus

    ... EPA United States Environmental Protection Agency Search Search Ozone Layer Protection Share Facebook Twitter Google+ Pinterest Contact Us Ozone Layer Protection Welcome to EPA's ozone layer protection web ...

  15. Palmitoylation of the feline immunodeficiency virus envelope glycoprotein and its effect on fusion activity and envelope incorporation into virions

    SciTech Connect

    Gonzalez, Silvia A.; Paladino, Monica G.; Affranchino, Jose L.

    2012-06-20

    The feline immunodeficiency virus (FIV) envelope glycoprotein (Env) possesses a short cytoplasmic domain of 53 amino acids containing four highly conserved cysteines at Env positions 804, 811, 815 and 848. Since palmitoylation of transmembrane proteins occurs at or near the membrane anchor, we investigated whether cysteines 804, 811 and 815 are acylated and analyzed the relevance of these residues for Env functions. Replacement of cysteines 804, 811 and 815 individually or in combination by serine residues resulted in Env glycoproteins that were efficiently expressed and processed. However, mutations C804S and C811S reduced Env fusogenicity by 93% and 84%, respectively, compared with wild-type Env. By contrast, mutant C815S exhibited a fusogenic capacity representing 50% of the wild-type value. Remarkably, the double mutation C804S/C811S abrogated both Env fusion activity and Env incorporation into virions. Finally, by means of Click chemistry assays we demonstrated that the four FIV Env cytoplasmic cysteines are palmitoylated.

  16. N-terminal sequences from Autographa californica nuclear polyhedrosis virus envelope proteins ODV-E66 and ODV-E25 are sufficient to direct reporter proteins to the nuclear envelope, intranuclear microvesicles and the envelope of occlusion derived virus.

    PubMed

    Hong, T; Summers, M D; Braunagel, S C

    1997-04-15

    Baculovirus occlusion-derived virus (ODV) derives its envelope from an intranuclear membrane source. N-terminal amino acid sequences of the Autographa californica nuclear polyhedrosis virus (AcMNPV) envelope proteins, ODV-E66 and ODV-E25 (23 and 24 amino acids, respectively) are highly hydrophobic. Recombinant viruses that express the two N-terminal amino acid sequences fused to green fluorescent protein (23GFP or 24GFP) provided visual markers to follow protein transport and localization within the nucleus during infection. Autoflourescence was first detected along the cytoplasmic periphery of the nucleus and subsequently localized as foci to discrete locations within the nucleus. Immunoelectron microscopy confirmed that these foci predominantly contained intranuclear microvesicles and the reporter fusion proteins were also detected in cytoplasmic membranes near the nucleus, and the outer and inner nuclear membrane. Therefore, these defined hydrophobic domains are sufficient to direct native and fusion proteins to induced membrane microvesicles within a baculovirus-infected cell nucleus and the viral envelope. In addition, these data suggest that movement of these proteins into the nuclear envelope may initiate through cytoplasmic membranes, such as endoplasmic reticulum, and that transport into the nucleus may be mediated through the outer and inner nuclear membrane.

  17. Protective Clothing

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Beta Glass material, originating from the Apollo program is supplied to Fyrepel by Owens-Corning and incorporated into Fyrepel's Fyretex and Beta-Mex aluminized fabrics. Fabrics are used in fire entry suits, several other types of protective suits for wear in hot industrial environments and such accessory items as heat-reflecting curtains for industrial applications.

  18. Methanol along the path from envelope to protoplanetary disc

    NASA Astrophysics Data System (ADS)

    Drozdovskaya, Maria N.; Walsh, Catherine; Visser, Ruud; Harsono, Daniel; van Dishoeck, Ewine F.

    2014-11-01

    Interstellar methanol is considered to be a parent species of larger, more complex organic molecules. A physicochemical simulation of infalling parcels of matter is performed for a low-mass star-forming system to trace the chemical evolution from cloud to disc. An axisymmetric 2D semi-analytic model generates the time-dependent density and velocity distributions, and full continuum radiative transfer is performed to calculate the dust temperature and the UV radiation field at each position as a function of time. A comprehensive gas-grain chemical network is employed to compute the chemical abundances along infall trajectories. Two physical scenarios are studied, one in which the dominant disc growth mechanism is viscous spreading, and another in which continuous infall of matter prevails. The results show that the infall path influences the abundance of methanol entering each type of disc, ranging from complete loss of methanol to an enhancement by a factor of >1 relative to the prestellar phase. Critical chemical processes and parameters for the methanol chemistry under different physical conditions are identified. The exact abundance and distribution of methanol is important for the budget of complex organic molecules in discs, which will be incorporated into forming planetary system objects such as protoplanets and comets. These simulations show that the comet-forming zone contains less methanol than in the precollapse phase, which is dominantly of prestellar origin, but also with additional layers built up in the envelope during infall. Such intriguing links will soon be tested by upcoming data from the Rosetta mission.

  19. Genotypic and functional properties of early infant HIV-1 envelopes

    PubMed Central

    2011-01-01

    Background Understanding the properties of HIV-1 variants that are transmitted from women to their infants is crucial to improving strategies to prevent transmission. In this study, 162 full-length envelope (env) clones were generated from plasma RNA obtained from 5 HIV-1 Clade B infected mother-infant pairs. Following extensive genotypic and phylogenetic analyses, 35 representative clones were selected for functional studies. Results Infant quasispecies were highly homogeneous and generally represented minor maternal variants, consistent with transmission across a selective bottleneck. Infant clones did not differ from the maternal in env length, or glycosylation. All infant variants utilized the CCR5 co-receptor, but were not macrophage tropic. Relatively high levels (IC50 ≥ 100 μg/ml) of autologous maternal plasma IgG were required to neutralize maternal and infant viruses; however, all infant viruses were neutralized by pooled sera from HIV-1 infected individuals, implying that they were not inherently neutralization-resistant. All infant viruses were sensitive to the HIV-1 entry inhibitors Enfuvirtide and soluble CD4; none were resistant to Maraviroc. Sensitivity to human monoclonal antibodies 4E10, 2F5, b12 and 2G12 varied. Conclusions This study provides extensive characterization of the genotypic and functional properties of HIV-1 env shortly after transmission. We present the first detailed comparisons of the macrophage tropism of infant and maternal env variants and their sensitivity to Maraviroc, the only CCR5 antagonist approved for therapeutic use. These findings may have implications for improving approaches to prevent mother-to-child HIV-1 transmission. PMID:21843318

  20. Ceiling fans as extenders of the summer comfort envelope

    SciTech Connect

    Rohles, F.M.; Jones, B.W.; Konz, S.A.

    1983-01-01

    The ASHRAE Standard 55-1981 specifies temperature limits or zones for winter and summer comfort. It states that the upper limit of the summer comfort zone, which is 79/sup 0/F or 26/sup 0/C, can be extended to 82/sup 0/F or 28/sup 0/C with air velocities of 160 fpm or 0.8 m/s. The manufacturers of ceiling fans claim comfort may be obtained at velocities considerably below the 160 fpm (0.8 m/s) level. They further claim that 82/sup 0/F (28/sup 0/C) with a ceiling fan will provide the same amount of comfort as 75/sup 0/F (24/sup 0/C) without a fan. Since ceiling fans require less than a penny per hour to operate, their use, as opposed to air conditioning, could represent a large energy savings without affecting human comfort. The National Bureau of Standards suggests a reduction in air conditioning demand of 3%//sup 0/F (5.4%/C). Thus the energy saving provided by 140 fpm (0.7 m/s) from a ceiling fan would be 5.6/sup 0/F X 3%//sup 0/F = 17%. Thus it was concluded that a ceiling fan may extend the upper limit of the summer comfort envelope from 79/sup 0/F (26/sup 0/C) to 85/sup 0/F (29/sup 0/C) (the equivalent temperature on any specific situation depends on the velocity of the air on the person). The results suggest that the turbulent and variable characteristics of the air plume of the ceiling fan may be its major comfort-producing feature.