Synapses of amphids defective (SAD-A) kinase promotes glucose-stimulated insulin secretion through activation of p21-activated kinase (PAK1) in pancreatic β-Cells.

PubMed

Nie, Jia; Sun, Chao; Faruque, Omar; Ye, Guangming; Li, Jia; Liang, Qiangrong; Chang, Zhijie; Yang, Wannian; Han, Xiao; Shi, Yuguang

2012-07-27

The p21-activated kinase-1 (PAK1) is implicated in regulation of insulin exocytosis as an effector of Rho GTPases. PAK1 is activated by the onset of glucose-stimulated insulin secretion (GSIS) through phosphorylation of Thr-423, a major activation site by Cdc42 and Rac1. However, the kinase(s) that phosphorylates PAK1 at Thr-423 in islet β-cells remains elusive. The present studies identified SAD-A (synapses of amphids defective), a member of AMP-activated protein kinase-related kinases exclusively expressed in brain and pancreas, as a key regulator of GSIS through activation of PAK1. We show that SAD-A directly binds to PAK1 through its kinase domain. The interaction is mediated by the p21-binding domain (PBD) of PAK1 and requires both kinases in an active conformation. The binding leads to direct phosphorylation of PAK1 at Thr-423 by SAD-A, triggering the onset of GSIS from islet β-cells. Consequently, ablation of PAK1 kinase activity or depletion of PAK1 expression completely abolishes the potentiating effect of SAD-A on GSIS. Consistent with its role in regulating GSIS, overexpression of SAD-A in MIN6 islet β-cells significantly stimulated cytoskeletal remodeling, which is required for insulin exocytosis. Together, the present studies identified a critical role of SAD-A in the activation of PAK1 during the onset of insulin exocytosis.

Structural optimization of SadA, an Fe(II)- and α-ketoglutarate-dependent dioxygenase targeting biocatalytic synthesis of N-succinyl-L-threo-3,4-dimethoxyphenylserine.

PubMed

Qin, Hui-Min; Miyakawa, Takuya; Nakamura, Akira; Hibi, Makoto; Ogawa, Jun; Tanokura, Masaru

2014-08-08

L-threo-3,4-Dihydroxyphenylserine (l-DOPS, Droxidopa) is a psychoactive drug and synthetic amino acid precursor that acts as a prodrug to the neurotransmitters. SadA, a dioxygenase from Burkholderia ambifaria AMMD, is an Fe(II)- and α-ketoglutarate (KG)-dependent enzyme that catalyzes N-substituted branched-chain or aromatic l-amino acids. SadA is able to produce N-succinyl-l-threo-3,4-dimethoxyphenylserine (NSDOPS), which is a precursor of l-DOPS, by catalyzing the hydroxylation of N-succinyl-3,4-dimethoxyphenylalanine (NSDOPA). However, the catalytic activity of SadA toward NSDOPS is much lower than that toward N-succinyl branched-chain l-amino acids. Here, we report an improved biocatalytic synthesis of NSDOPS with SadA. Structure-based protein engineering was applied to improve the α-KG turnover activity for the synthesis of NSDOPS. The G79A, G79A/F261W or G79A/F261R mutant showed a more than 6-fold increase in activity compared to that of the wild-type enzyme. The results provide a new insight into the substrate specificity toward NSDOPA and will be useful for the rational design of SadA mutants as a target of industrial biocatalysts. Copyright © 2014 Elsevier Inc. All rights reserved.

The loss of the kinases SadA and SadB results in early neuronal apoptosis and a reduced number of progenitors.

PubMed

Dhumale, Pratibha; Menon, Sindhu; Chiang, Joanna; Püschel, Andreas W

2018-01-01

The neurons that form the mammalian neocortex originate from progenitor cells in the ventricular (VZ) and subventricular zone (SVZ). Newborn neurons are multipolar but become bipolar during their migration from the germinal layers to the cortical plate (CP) by forming a leading process and an axon that extends in the intermediate zone (IZ). Once they settle in the CP, neurons assume a highly polarized morphology with a single axon and multiple dendrites. The AMPK-related kinases SadA and SadB are intrinsic factors that are essential for axon formation during neuronal development downstream of Lkb1. The knockout of both genes encoding Sad kinases (Sada and Sadb) results not only in a loss of axons but also a decrease in the size of the cortical plate. The defect in axon formation has been linked to a function of Sad kinases in the regulation of microtubule binding proteins. However, the causes for the reduced size of the cortical plate in the Sada-/-;Sadb-/- knockout remain to be analyzed in detail. Here we show that neuronal cell death is increased and the number of neural progenitors is decreased in the Sada-/-;Sadb-/- CP. The reduced number of progenitors is a non-cell autonomous defect since they do not express Sad kinases. These defects are restricted to the neocortex while the hippocampus remains unaffected.

SaDA: From Sampling to Data Analysis—An Extensible Open Source Infrastructure for Rapid, Robust and Automated Management and Analysis of Modern Ecological High-Throughput Microarray Data

PubMed Central

Singh, Kumar Saurabh; Thual, Dominique; Spurio, Roberto; Cannata, Nicola

2015-01-01

One of the most crucial characteristics of day-to-day laboratory information management is the collection, storage and retrieval of information about research subjects and environmental or biomedical samples. An efficient link between sample data and experimental results is absolutely important for the successful outcome of a collaborative project. Currently available software solutions are largely limited to large scale, expensive commercial Laboratory Information Management Systems (LIMS). Acquiring such LIMS indeed can bring laboratory information management to a higher level, but most of the times this requires a sufficient investment of money, time and technical efforts. There is a clear need for a light weighted open source system which can easily be managed on local servers and handled by individual researchers. Here we present a software named SaDA for storing, retrieving and analyzing data originated from microorganism monitoring experiments. SaDA is fully integrated in the management of environmental samples, oligonucleotide sequences, microarray data and the subsequent downstream analysis procedures. It is simple and generic software, and can be extended and customized for various environmental and biomedical studies. PMID:26047146

SaDA: From Sampling to Data Analysis-An Extensible Open Source Infrastructure for Rapid, Robust and Automated Management and Analysis of Modern Ecological High-Throughput Microarray Data.

PubMed

Singh, Kumar Saurabh; Thual, Dominique; Spurio, Roberto; Cannata, Nicola

2015-06-03

One of the most crucial characteristics of day-to-day laboratory information management is the collection, storage and retrieval of information about research subjects and environmental or biomedical samples. An efficient link between sample data and experimental results is absolutely important for the successful outcome of a collaborative project. Currently available software solutions are largely limited to large scale, expensive commercial Laboratory Information Management Systems (LIMS). Acquiring such LIMS indeed can bring laboratory information management to a higher level, but most of the times this requires a sufficient investment of money, time and technical efforts. There is a clear need for a light weighted open source system which can easily be managed on local servers and handled by individual researchers. Here we present a software named SaDA for storing, retrieving and analyzing data originated from microorganism monitoring experiments. SaDA is fully integrated in the management of environmental samples, oligonucleotide sequences, microarray data and the subsequent downstream analysis procedures. It is simple and generic software, and can be extended and customized for various environmental and biomedical studies.

Characterization of two mosquito STATs, AaSTAT and CtSTAT. Differential regulation of tyrosine phosphorylation and DNA binding activity by lipopolysaccharide treatment and by Japanese encephalitis virus infection.

PubMed

Lin, Chang-Chi; Chou, Chih-Ming; Hsu, Ya-Li; Lien, Jih-Ching; Wang, Yu-Ming; Chen, Shui-Tsung; Tsai, Shu-Chuan; Hsiao, Pei-Wen; Huang, Chang-Jen

2004-01-30

Two mosquito STATs, AaSTAT and CtSTAT, have been cloned from Aedes albopictus and Culex tritaeniorhynchus mosquitoes, respectively. These two STATs are more similar to those of Drosophila, Anopheles, and mammalian STAT5 in the DNA binding and Src homology 2 domains. The mRNA transcripts are expressed at all developmental stages, and the proteins are present predominantly at the pupal and adult stages in both mosquitoes. Stimulation with lipopolysaccharide resulted in an increase of tyrosine phosphorylation and DNA binding activity of AaSTAT and CtSTAT as well as an increase of luciferase activity of a reporter gene containing Drosophila STAT binding motif in mosquito C6/36 cells. After being infected with Japanese encephalitis virus, nuclear extracts of C6/36 cells revealed a decrease of tyrosine phosphorylation and DNA binding activity of AaSTAT which could be restored by sodium orthovanadate treatment. Taking all of the data together, this is the first report to clone and characterize two mosquito STATs with 81% identity and to demonstrate a different response of tyrosine phosphorylation and DNA binding of these two STATs by lipopolysaccharide treatment and by Japanese encephalitis virus infection.

TM9/Phg1 and SadA proteins control surface expression and stability of SibA adhesion molecules in Dictyostelium.

PubMed

Froquet, Romain; le Coadic, Marion; Perrin, Jackie; Cherix, Nathalie; Cornillon, Sophie; Cosson, Pierre

2012-02-01

TM9 proteins form a family of conserved proteins with nine transmembrane domains essential for cellular adhesion in many biological systems, but their exact role in this process remains unknown. In this study, we found that genetic inactivation of the TM9 protein Phg1A dramatically decreases the surface levels of the SibA adhesion molecule in Dictyostelium amoebae. This is due to a decrease in sibA mRNA levels, in SibA protein stability, and in SibA targeting to the cell surface. A similar phenotype was observed in cells devoid of SadA, a protein that does not belong to the TM9 family but also exhibits nine transmembrane domains and is essential for cellular adhesion. A contact site A (csA)-SibA chimeric protein comprising only the transmembrane and cytosolic domains of SibA and the extracellular domain of the Dictyostelium surface protein csA also showed reduced stability and relocalization to endocytic compartments in phg1A knockout cells. These results indicate that TM9 proteins participate in cell adhesion by controlling the levels of adhesion proteins present at the cell surface.

Comparison of risk-based decision-support systems for brownfield site rehabilitation: DESYRE and SADA applied to a Romanian case study.

PubMed

Stezar, I C; Pizzol, L; Critto, A; Ozunu, A; Marcomini, A

2013-12-15

Brownfield rehabilitation is an essential step for sustainable land-use planning and management in the European Union. In brownfield regeneration processes, the legacy contamination plays a significant role, firstly because of the persistent contaminants in soil or groundwater which extends the existing hazards and risks well into the future; and secondly, problems from historical contamination are often more difficult to manage than contamination caused by new activities. Due to the complexity associated with the management of brownfield site rehabilitation, Decision Support Systems (DSSs) have been developed to support problem holders and stakeholders in the decision-making process encompassing all phases of the rehabilitation. This paper presents a comparative study between two DSSs, namely SADA (Spatial Analysis and Decision Assistance) and DESYRE (Decision Support System for the Requalification of Contaminated Sites), with the main objective of showing the benefits of using DSSs to introduce and process data and then to disseminate results to different stakeholders involved in the decision-making process. For this purpose, a former car manufacturing plant located in the Brasov area, Central Romania, contaminated chiefly by heavy metals and total petroleum hydrocarbons, has been selected as a case study to apply the two examined DSSs. Major results presented here concern the analysis of the functionalities of the two DSSs in order to identify similarities, differences and complementarities and, thus, to provide an indication of the most suitable integration options. Copyright © 2013 Elsevier Ltd. All rights reserved.

Analytical Kinematics and Coupled Vibrations Analysis of Mechanical System Operated by Solar Array Drive Assembly

NASA Astrophysics Data System (ADS)

Sattar, M.; Wei, C.; Jalali, A.; Sattar, R.

2017-07-01

To address the impact of solar array (SA) anomalies and vibrations on performance of precision space-based operations, it is important to complete its accurate jitter analysis. This work provides mathematical modelling scheme to approximate kinematics and coupled micro disturbance dynamics of rigid load supported and operated by solar array drive assembly (SADA). SADA employed in analysis provides a step wave excitation torque to activate the system. Analytical investigations into kinematics is accomplished by using generalized linear and Euler angle coordinates, applying multi-body dynamics concepts and transformations principles. Theoretical model is extended, to develop equations of motion (EoM), through energy method (Lagrange equation). The main emphasis is to research coupled frequency response by determining energies dissipated and observing dynamic behaviour of internal vibratory systems of SADA. The disturbance model captures discrete active harmonics of SADA, natural modes and vibration amplifications caused by interactions between active harmonics and structural modes of mechanical assembly. The proposed methodology can help to predict true micro disturbance nature of SADA operating rigid load. Moreover, performance outputs may be compared against actual mission requirements to assess precise spacecraft controller design to meet next space generation stringent accuracy goals.

Spatial Approaches for Ecological Screening and Exposure Assessment of Chemicals and Radionclides

EPA Science Inventory

This presentation details a tool, SADA, available for use in environmental assessments of chemicals that can also be used for radiological assessments of the environment. Spatial Analysis and Decision Assistance (SADA) is a Windows freeware program that incorporates tools from e...

Environmental Tools and Radiological Assessment

EPA Science Inventory

This presentation details two tools (SADA and FRAMES) available for use in environmental assessments of chemicals that can also be used for radiological assessments of the environment. Spatial Analysis and Decision Assistance (SADA) is a Windows freeware program that incorporate...

Standard module approach to scanning requirements for second-generation airborne FLIRs

NASA Astrophysics Data System (ADS)

Ludwiszewski, Alan P.

1995-05-01

This paper examines the specification requirements for the development of standard module scanning components to be used in conjunction with SADA I and SADA II sensor arrays. System-level design considerations are presented to identify a selection of components that is consistent with optimum use of the SADA technology. A limited-rotation electromagnetic actuator, used in conjunction with an angular position sensor and a digital controller, is shown to have the necessary performance and flexibility to perform the frame scan function for a wide range of airborne systems. System level requirements and specifications for an optional interlace scan system are also provided.

Lightcurve Analysis of 932 Hooveria

NASA Astrophysics Data System (ADS)

Warner, Brian D.; Sada, Pedro V.; Pollock, J.; Reichart, Daniel; Ivarsen, Ivan; Haislip, Josh; Lacluyze, Aaron; Nysewander, Melissa

2010-10-01

CCD observations of the main-belt asteroid 932 Hooveria in 2010 February and March led to a lightcurve with a synodic period of P = 39.15 ± 0.05 h. This contradicted a period of 30 h (Sada, 2004). Re-analysis of the Sada data set gives P = 39.23 ± 0.02 h, putting the two periods in fairly close agreement.

Manufacturing Methods and Technology Program Plan, CY 1986

DTIC Science & Technology

1986-02-01

Sada Barik ) C: (201) 5 32- 4 035 Fort Monmouth, NJ 07T03 AV: 992-4995 DESCOM U.S. Army Depot Systems Command ATTN: AMSDS-RM-EM (-Mr. Mike Ahearn) C...A.MSETL-PC-SI-I (Mr. Sada Barik ) (-r, ATTN: AMSEL-POD-P-G (Messrs. Feddeler, Esposito, Resnic) Cdt ATTN: RD&E Technical Documents Center PM, 6ITTN: AMCPM

A Trimeric Lipoprotein Assists in Trimeric Autotransporter Biogenesis in Enterobacteria*

PubMed Central

Grin, Iwan; Hartmann, Marcus D.; Sauer, Guido; Hernandez Alvarez, Birte; Schütz, Monika; Wagner, Samuel; Madlung, Johannes; Macek, Boris; Felipe-Lopez, Alfonso; Hensel, Michael; Lupas, Andrei; Linke, Dirk

2014-01-01

Trimeric autotransporter adhesins (TAAs) are important virulence factors of many Gram-negative bacterial pathogens. TAAs form fibrous, adhesive structures on the bacterial cell surface. Their N-terminal extracellular domains are exported through a C-terminal membrane pore; the insertion of the pore domain into the bacterial outer membrane follows the rules of β-barrel transmembrane protein biogenesis and is dependent on the essential Bam complex. We have recently described the full fiber structure of SadA, a TAA of unknown function in Salmonella and other enterobacteria. In this work, we describe the structure and function of SadB, a small inner membrane lipoprotein. The sadB gene is located in an operon with sadA; orthologous operons are only found in enterobacteria, whereas other TAAs are not typically associated with lipoproteins. Strikingly, SadB is also a trimer, and its co-expression with SadA has a direct influence on SadA structural integrity. This is the first report of a specific export factor of a TAA, suggesting that at least in some cases TAA autotransport is assisted by additional periplasmic proteins. PMID:24369174

GENERAL: Application of Symplectic Algebraic Dynamics Algorithm to Circular Restricted Three-Body Problem

NASA Astrophysics Data System (ADS)

Lu, Wei-Tao; Zhang, Hua; Wang, Shun-Jin

2008-07-01

Symplectic algebraic dynamics algorithm (SADA) for ordinary differential equations is applied to solve numerically the circular restricted three-body problem (CR3BP) in dynamical astronomy for both stable motion and chaotic motion. The result is compared with those of Runge-Kutta algorithm and symplectic algorithm under the fourth order, which shows that SADA has higher accuracy than the others in the long-term calculations of the CR3BP.

Micro-Vibration Performance Prediction of SEPTA24 Using SMeSim (RUAG Space Mechanism Simulator Tool)

NASA Astrophysics Data System (ADS)

Omiciuolo, Manolo; Lang, Andreas; Wismer, Stefan; Barth, Stephan; Szekely, Gerhard

2013-09-01

Scientific space missions are currently challenging the performances of their payloads. The performances can be dramatically restricted by micro-vibration loads generated by any moving parts of the satellites, thus by Solar Array Drive Assemblies too. Micro-vibration prediction of SADAs is therefore very important to support their design and optimization in the early stages of a programme. The Space Mechanism Simulator (SMeSim) tool, developed by RUAG, enhances the capability of analysing the micro-vibration emissivity of a Solar Array Drive Assembly (SADA) under a specified set of boundary conditions. The tool is developed in the Matlab/Simulink® environment throughout a library of blocks simulating the different components a SADA is made of. The modular architecture of the blocks, assembled by the user, and the set up of the boundary conditions allow time-domain and frequency-domain analyses of a rigid multi-body model with concentrated flexibilities and coupled- electronic control of the mechanism. SMeSim is used to model the SEPTA24 Solar Array Drive Mechanism and predict its micro-vibration emissivity. SMeSim and the return of experience earned throughout its development and use can now support activities like verification by analysis of micro-vibration emissivity requirements and/or design optimization to minimize the micro- vibration emissivity of a SADA.

SadA-Expressing Staphylococci in the Human Gut Show Increased Cell Adherence and Internalization.

PubMed

Luqman, Arif; Nega, Mulugeta; Nguyen, Minh-Thu; Ebner, Patrick; Götz, Friedrich

2018-01-09

A subgroup of biogenic amines, the so-called trace amines (TAs), are produced by mammals and bacteria and can act as neuromodulators. In the genus Staphylococcus, certain species are capable of producing TAs through the activity of staphylococcal aromatic amino acid decarboxylase (SadA). SadA decarboxylates aromatic amino acids to produce TAs, as well as dihydroxy phenylalanine and 5-hydroxytryptophan to thus produce the neurotransmitters dopamine and serotonin. SadA-expressing staphylococci were prevalent in the gut of most probands, where they are part of the human intestinal microflora. Furthermore, sadA-expressing staphylococci showed increased adherence to HT-29 cells and 2- to 3-fold increased internalization. Internalization and adherence was also increased in a sadA mutant in the presence of tryptamine. The α2-adrenergic receptor is required for enhanced adherence and internalization. Thus, staphylococci in the gut might contribute to gut activity and intestinal colonization. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Structure and inhibition analysis of the mouse SAD-B C-terminal fragment.

PubMed

Ma, Hui; Wu, Jing-Xiang; Wang, Jue; Wang, Zhi-Xin; Wu, Jia-Wei

2016-10-01

The SAD (synapses of amphids defective) kinases, including SAD-A and SAD-B, play important roles in the regulation of neuronal development, cell cycle, and energy metabolism. Our recent study of mouse SAD-A identified a unique autoinhibitory sequence (AIS), which binds at the junction of the kinase domain (KD) and the ubiquitin-associated (UBA) domain and exerts autoregulation in cooperation with UBA. Here, we report the crystal structure of the mouse SAD-B C-terminal fragment including the AIS and the kinase-associated domain 1 (KA1) at 2.8 Å resolution. The KA1 domain is structurally conserved, while the isolated AIS sequence is highly flexible and solvent-accessible. Our biochemical studies indicated that the SAD-B AIS exerts the same autoinhibitory role as that in SAD-A. We believe that the flexible isolated AIS sequence is readily available for interaction with KD-UBA and thus inhibits SAD-B activity.

Status and distribution of the angonoka tortoise (Geochelone yniphora) of western Madagascar

USGS Publications Warehouse

Smith, Lora L.; Reid, Don; Robert, Bourou; Joby, Mahatoly; Clement, Sibo

1999-01-01

From 1993 to 1995, field surveys were conducted in western Madagascar to assess the current status of the angonoka tortoise (Geochelone yniphora) in the wild. Tortoise presence was documented at 10 of 11 localities surveyed. These localities represent at least five populations, all within a 30-km radius of Baly Bay, near the town of Soalala. The populations occur on fragments of habitat ranging from <50 to 4–6000 ha in size. One hundred and forty-five tortoises were marked in the five populations. Hatchling or juvenile tortoises were observed in all populations, indicating that reproduction was occurring. Most of the 145 tortoises (68%) were marked on Cape Sada, where monthly surveys were conducted. The tortoise density on the c. 150 ha peninsula was 0.66 tortoises/ha. The remains of 22 dead juveniles were found on Cape Sada over the 2-year period. This evidence, combined with the low number of juveniles in intermediate size classes in the Cape Sada population suggests that juvenile mortality may be high.

Thermal design of the XTE deployables

NASA Astrophysics Data System (ADS)

Neuberger, David

1997-01-01

This paper describes the thermal design and flight results of the X-Ray Timing Explorer (XTE) deployable mechanisms. The two subsystems discussed are the SADA and the APS gimbal. The SADA (Solar Array Drive Assembly) is the mechanism that maneuvers the solar arrays during flight operation and the APS gimbal (Antenna Pointing System gimbal) is the mechanism that maneuvers the high gain antenna during flight operation. Testing and analysis will be covered where appropriate and flight results will be given and compared to requirements. The XTE spacecraft was launched in December 30, 1995at8:40 EST. The solar arrays and both high gain antennas deployed nominally and are operating within their temperature limits.

Performance enhancement of linear stirling cryocoolers

NASA Astrophysics Data System (ADS)

Korf, Herbert; Ruehlich, Ingo; Wiedmann, Th.

2000-12-01

Performance and reliability parameters of the AIM Stirling coolers have been presented in several previous publications. This paper focuses on recent developments at AIM for the COP improvement of cryocoolers in IR-detectors and systems applications. Improved COP of cryocoolers is a key for optimized form factors, weight and reliability. In addition, some systems are critical for minimum input power and consequently minimum electromagnetic interference or magnetic stray fields, heat sinking or minimum stress under high g-level, etc. Although performance parameters and loss mechanism are well understood and can be calculated precisely, several losses still had been excessive and needed to be minimized. The AIM program is based on the SADA I cryocooler, which now is optimized to carry 4.3 W net heat load at 77K. As this program will lead into applications on a space platform, in a next step AIM is introducing flexure bearings and in a final step, an advanced pulse tube cold head will be implemented. The performance of the SADA II cooler is also improved by using the same tools and methods than used for the performance increase of the SADA I cooler by a factor of two. The main features are summarized together with measured or calculated performance data.

Crystal Structure of a Novel N-Substituted L-Amino Acid Dioxygenase from Burkholderia ambifaria AMMD

PubMed Central

Qin, Hui-Min; Miyakawa, Takuya; Jia, Min Ze; Nakamura, Akira; Ohtsuka, Jun; Xue, You-Lin; Kawashima, Takashi; Kasahara, Takuya; Hibi, Makoto; Ogawa, Jun; Tanokura, Masaru

2013-01-01

A novel dioxygenase from Burkholderia ambifaria AMMD (SadA) stereoselectively catalyzes the C3-hydroxylation of N-substituted branched-chain or aromatic L-amino acids, especially N-succinyl-L-leucine, coupled with the conversion of α-ketoglutarate to succinate and CO2. To elucidate the structural basis of the substrate specificity and stereoselective hydroxylation, we determined the crystal structures of the SadA.Zn(II) and SadA.Zn(II).α-KG complexes at 1.77 Å and 1.98 Å resolutions, respectively. SadA adopted a double-stranded β-helix fold at the core of the structure. In addition, an HXD/EXnH motif in the active site coordinated a Zn(II) as a substitute for Fe(II). The α-KG molecule also coordinated Zn(II) in a bidentate manner via its 1-carboxylate and 2-oxo groups. Based on the SadA.Zn(II).α-KG structure and mutation analyses, we constructed substrate-binding models with N-succinyl-L-leucine and N-succinyl-L-phenylalanine, which provided new insight into the substrate specificity. The results will be useful for the rational design of SadA variants aimed at the recognition of various N-succinyl L-amino acids. PMID:23724013

Input Shaping to Reduce Solar Array Structural Vibrations

NASA Technical Reports Server (NTRS)

Doherty, Michael J.; Tolson, Robert J.

1998-01-01

Structural vibrations induced by actuators can be minimized using input shaping. Input shaping is a feedforward method in which actuator commands are convolved with shaping functions to yield a shaped set of commands. These commands are designed to perform the maneuver while minimizing the residual structural vibration. In this report, input shaping is extended to stepper motor actuators. As a demonstration, an input-shaping technique based on pole-zero cancellation was used to modify the Solar Array Drive Assembly (SADA) actuator commands for the Lewis satellite. A series of impulses were calculated as the ideal SADA output for vibration control. These impulses were then discretized for use by the SADA stepper motor actuator and simulated actuator outputs were used to calculate the structural response. The effectiveness of input shaping is limited by the accuracy of the knowledge of the modal frequencies. Assuming perfect knowledge resulted in significant vibration reduction. Errors of 10% in the modal frequencies caused notably higher levels of vibration. Controller robustness was improved by incorporating additional zeros in the shaping function. The additional zeros did not require increased performance from the actuator. Despite the identification errors, the resulting feedforward controller reduced residual vibrations to the level of the exactly modeled input shaper and well below the baseline cases. These results could be easily applied to many other vibration-sensitive applications involving stepper motor actuators.

An Environmental Decision Support System for Spatial Assessment and Selective Remediation

EPA Science Inventory

Spatial Analysis and Decision Assistance (SADA) is a Windows freeware program that incorporates environmental assessment tools for effective problem-solving. The software integrates modules for GIS, visualization, geospatial analysis, statistical analysis, human health and ecolog...

Leveraging metal matrix composites to reduce costs in space mechanisms

NASA Technical Reports Server (NTRS)

Nye, Ted; Claridge, Rex; Walker, Jim

1994-01-01

Advanced metal matrix composites may be one of the most promising technologies for reducing cost in structural components without compromise to strength or stiffness. A microlight 12.50 N (2.81 lb), two-axis, solar array drive assembly (SADA) was made for the Advanced Materials Applications to Space Structures (AMASS) Program flight experiment. The SADA had both its inner and outer axis housings fabricated from silicon carbide particulate reinforced alumimun. Two versions of the housings were made. The first was machined from a solid billet of material. The second was plaster cast to a near net shape that required minimal finish machining. Both manufacturing methods were compared upon completion. Results showed a cost savings with the cast housing was possible for quantities greater than one and probable for quantities greater than two. For quantities approaching ten, casting resulted in a reduction factor of almost three in the cost per part.

Flexure bearing compressor in the one watt linear (OWL) envelope

NASA Astrophysics Data System (ADS)

Rühlich, I.; Mai, M.; Wiedmann, Th.; Rosenhagen, C.

2007-04-01

For high performance IR detectors the split linear cooler is a preferred solution. High reliability, low induced vibration and low audible noise are major benefits of such coolers. Today, most linear coolers are qualified for MTTF of 8,000h or above. It is a strong customer desire to further reduce the maintenance costs on system level with significantly higher cooler lifetime. Increased cooler MTTF figures are also needed for IR applications with high lifetime requirements like missile warning applications, border surveillance or homeland security applications. AIM developed a Moving Magnet Flexure Bearing compressor to meet a MTTF of minimum 20,000h. The compressor has a full flexure bearing support on both sides of the driving mechanism. In the assembly process of the compressor an automated alignment process is used to achieve the necessary accuracy. Thus, side-forces on the pistons are minimized during operation, which significantly reduces the wear-out. In order to reduce the outgassing potential most of the internal junctions are welded and the use of all non-metallic components is minimized. The outline dimensions comply with the SADA2 requirements in length and diameter. Further, when operated with a 1/2" SADA type coldfinger, the cooler meets all specified performance data for SADA2. The compressor can be combined with different Stirling type coldfingers and also with the AIM Pulse Tube coldfinger, which gives increased lifetime potential up to 50,000h MTTF. Technical details and performance data of the new compressor are shown.

ICC Type II large-format FPA detector assemblies

NASA Astrophysics Data System (ADS)

Clynne, Thomas H.; Powers, Thomas P.

1997-08-01

ICC presents a new addition to their integrated detector assembly product line with the announcement of their type II large format staring class FPA units. A result of internally funded research and development, the ICC type II detector assembly can accommodate all existing large format staring class PtSi, InSb and MCT focal planes, up to 640 by 480. Proprietary methodologies completely eliminate all FPA stresses to allow for maximum FPA survivability. Standard optical and cryocooler interfaces allow for the use of BEI, AEG, TI SADA Hughes/Magnavox and Joule Thompson coolers. This unit has been qualified to the current SADA II thermal environmental specifications and was tailored around ICC's worldwide industry standard type IV product. Assembled in a real world flexible manufacturing environment, this unit features a wide degree of adaptability and can be easily modified to a user's specifications via standard options and add-ons that include optical interfaces, electrical interfaces and window/filter material selections.

Space assets for demining assistance

NASA Astrophysics Data System (ADS)

Kruijff, Michiel; Eriksson, Daniel; Bouvet, Thomas; Griffiths, Alexander; Craig, Matthew; Sahli, Hichem; González-Rosón, Fernando Valcarce; Willekens, Philippe; Ginati, Amnon

2013-02-01

Populations emerging from armed conflicts often remain threatened by landmines and explosive remnants of war. The international mine action community is concerned with the relief of this threat. The Space Assets for Demining Assistance (SADA) undertaking is a set of activities that aim at developing new services to improve the socio-economic impact of mine action activities, primarily focused on the release of land thought to be contaminated, a process described as land release. SADA was originally initiated by the International Astronautical Federation (IAF). It has been implemented under the Integrated Applications Promotion (IAP) program of the European Space Agency (ESA). Land release in mine action is the process whereby the demining community identifies, surveys and prioritizes suspected hazardous areas for more detailed investigation, which eventually results in the clearance of landmines and other explosives, thereby releasing land to the local population. SADA has a broad scope, covering activities, such as planning (risk and impact analysis, prioritization, and resource management), field operations and reporting. SADA services are developed in two phases: feasibility studies followed by demonstration projects. Three parallel feasibility studies have been performed. They aimed at defining an integrated set of space enabled services to support the land release process in mine action, and at analyzing their added value, viability and sustainability. The needs of the mine action sector have been assessed and the potential contribution of space assets has been identified. Support services have been formulated. To test their fieldability, proofs of concept involving mine action end users in various operational field settings have been performed by each of the study teams. The economic viability has also been assessed. Whenever relevant and cost-effective, SADA aims at integrating Earth observation data, GNSS navigation and SatCom technologies with existing

Development of a Solar Array Drive Assembly for CubeSat

NASA Technical Reports Server (NTRS)

Passaretti, Mike; Hayes, Ron

2010-01-01

Small satellites and in particular CubeSats, have increasingly become more viable as platforms for payloads typically requiring much larger bus structures. As advances in technology make payloads and instruments for space missions smaller, lighter and more power efficient, a niche market is emerging from the university community to perform rapidly developed, low-cost missions on very small spacecraft - micro, nano, and picosatellites. In just the last few years, imaging, biological and new technology demonstration missions have been either proposed or have flown using variations of the CubeSat structure as a basis. As these missions have become more complex, and the CubeSat standard has increased in both size (number of cubes) and mass, available power has become an issue. Body-mounted solar cells provide a minimal amount of power; deployable arrays improve on that baseline but are still limited. To truly achieve maximum power, deployed tracked arrays are necessary. To this end, Honeybee Robotics Spacecraft Mechanisms Corporation, along with MMA of Nederland Colorado, has developed a solar array drive assembly (SADA) and deployable solar arrays specifically for CubeSat missions. In this paper, we discuss the development of the SADA.

Characterization of Biofouling Marine Caulobacters and Their Adhesive Holdfast

DTIC Science & Technology

1988-06-30

SAD-A 197 211 _, 111 3 CEILL GJU JREPORT DOCUMENTATION PAGE la. REPORT SECURITY CLASSIFiCATION ’b RESTRICTIVE MARKIN6, S U 1 2a. SECURITY...what types of surfaces to which the Caulobacters will attach. This was approached by the preparation of glass surfaces covalently modified with a...finding that dimethyldichlorosilane treated glass (ie classical "silanizing") was reasonably effective in discouraging attachment, a convenience for many

Benzocaine-Induced Methemoglobinemia Attributed to Topical Application of the Anesthetic in Several Laboratory Animal Species

DTIC Science & Technology

1993-01-01

SAD-A273 571 T PON AGE DoaM No o,.Q ’a J 0Lt)141 IF( AND UAItS COVIAto 4. TITLE AND SUBfII( 5 FUNDING NUMBERS Benzocaine -inducd methemoglobinemia...PUBLIC RELEASE: DISTRIBUTION UNLIMITED * 13. ABSTRACT (Mj,,mum 200 wotds) Case reports of benzocaine -induced methemoglobinemia following application...for several types of experimental studies. We designed a screening study using a common topical benzocaine -contzining anesthetics. Response to

CTC Sentinel. Volume 3, Number 11-12, November 2010

DTIC Science & Technology

2010-11-01

crave freedom and reject tyranny, despotism, humility and subjugation. But you have followed an erroneous path.”7 Whereas al-Zindani preached fire ...established a Salafist center in the Zaydi stronghold of Sa`da in 1979, he again encountered resistance at the hands of their aristocracy and even...the imam in the Northern Civil War that lasted from 1962 to 1970 have encountered similar resistance when they tried to extend their authority

Qatar: Background and U.S. Relations

DTIC Science & Technology

2014-11-04

Ahmed bin Abdullah bin Ziad Al Mahmoud Foreign Minister Khalid Bin Mohammed Al Attiyah Minister of Energy and Industry Mohammed bin Saleh al Sada...about voter franchise extension were resolved.5 The Advisory Council would have oversight authority over the Council of Ministers and would be able...Sunni armed groups in Syria has the potential to have a more lasting impact on the region, but has challenged the traditional Qatari preference for

Qatar: Background and U.S. Relations

DTIC Science & Technology

2014-01-30

Industry Mohammed bin Saleh al Sada Minister of State for Defense Affairs MG Hamad bin Ali Al Attiyah Chief of Staff, Qatari Armed Forces MG Ghanim bin...May 2008 after concerns about voter franchise extension were resolved.5 The Advisory Council would have oversight authority over the Council of...have a more lasting impact on the region, but has challenged the traditional Qatari preference for remaining engaged with all sides in regional

Small Business Awards Program

DTIC Science & Technology

1987-01-12

Department of Defense - ’ ’> INSTRUCTION SAD-A269 980 o493 04199’ J3anuary 12, 1987 NUMBIPR 13 !•.SD (A) SUBJECT: Small Business Awards Program...References: (a) DoD Directive 4205.1, "DoD Small Business and Small Disadvantaged Business Utilization Programs," June 21, 1984 (b) DoD Federal Acquisition...the Department of Defense who have made significant contribution to the Small and Disadvantaged Business Utilization Program. 2. Prescribes

Solar array stepping problems in satellites and solutions

NASA Astrophysics Data System (ADS)

Maharana, P. K.; Goel, P. S.

1992-01-01

The dynamics problems arising due to stepping motion of the solar arrays of spacecraft are studied. To overcome these problems, design improvements in the drive logic based on the phase plane analysis are suggested. The improved designs are applied to the Solar Array Drive Assembly (SADA) of IRS-1B and INSAT-2A satellites. In addition, an alternate torquing strategy for very successful slewing of the arrays, and with minimum excitation of flexible modes, is proposed.

Simulation of solar array slewing of Indian remote sensing satellite

NASA Astrophysics Data System (ADS)

Maharana, P. K.; Goel, P. S.

The effect of flexible arrays on sun tracking for the IRS satellite is studied. Equations of motion of satellites carrying a rotating flexible appendage are developed following the Newton-Euler approach and utilizing the constrained modes of the appendage. The drive torque, detent torque and friction torque in the SADA are included in the model. Extensive simulations of the slewing motion are carried out. The phenomena of back-stepping, step-missing, step-slipping and the influences of array flexibility in the acquisition mode are observed for certain combinations of parameters.

Development of the LSF95xx 2nd generation flexure bearing coolers

NASA Astrophysics Data System (ADS)

Mullie, J. C.; Bruins, P. C.; Benschop, T.; Meijers, M.

2005-05-01

Thales Cryogenics has been working on high reliability cryocoolers since 1997. During this period two cooler series have been developed, the LSF91xx series for cooling powers up to 3W at 80K and the LSF93xx series for cooling powers up to 8W at 80K. As a result of several design improvements, it was possible to decrease the length and mass of our flexure-bearing coolers. These improvements have been applied in the new LSF95xx series. With the length and mass reduction, the LSF95xx complies with the SADA II specification with respect to envelope and mass. Based on this, Thales Cryogenics is the first manufacturer offering a full flexure-bearing supported cooler that fits within the SADA II envelope. By using a moving magnet configuration in all our flexure-bearing coolers, the risk with respect to contamination problems due to out-gassing has been diminished because the coils are not part of the helium circuit. Furthermore, all connections in the LSF95xx are laser-welded, which means that there is no additional locking required inside the cooler. By using a different magnet design, no magnet segments have to be glued together, which decreases the risk of out-gassing and increases the reliability even more. This paper describes the trade-offs that have been considered in the design phase, and gives a detailed overview of the test results, the status of the qualification program and the resulting specification of the LSF95xx cooler series.

Velocity and Vorticity Measurements of Jupiter's Great Red Spot Using Automated Cloud Feature Trackers

NASA Astrophysics Data System (ADS)

Choi, D. S.; Gierasch, P.; Banfield, D.; Showman, A.

2005-12-01

During the 28th orbit of Galileo in May 2000, the spacecraft imaged Jupiter's Great Red Spot (GRS) with a remarkable level of detail. Three observations of the vortex were made over a span of about two hours. We have produced mosaics of the GRS at each observation, and have measured the winds of the GRS using an automated algorithm that does not require manual cloud tracking. The advantage of using this method is the production of a high-density, regular grid of wind velocity vectors as compared to a limited number of scattered wind vectors that result from manual cloud tracking [1]. Using the wind velocity measurements, we are able to compute particle trajectories around the GRS as well as relative and absolute vorticities. We have also mapped turbulent eddies inside the chaotic central region of the GRS, similar to those tracked by Sada et al [2]. We calculate how absolute vorticity changes as a function of latitude along a trajectory around the GRS and compare these measurements to similar ones performed by Dowling and Ingersoll using Voyager imaging data [3]. Future projects with the automated cloud feature trackers will analyze Voyager images of the GRS as well as other high-resolution images of Jovian vortices. We also hope to apply this method to other relevant datasets on planetary atmospheres. References: [1] Legarreta, J. and Sanchez-Lavega, A. (2005) Icarus 174: 178--191. [2] Sada, P. et al. (1996) Icarus 119: 311--335. [3] Dowling, T. and Ingersoll, A. (1988) J. Atm. Sci. 45: 1380--1396.

Raytheon dual-use long life cryocooler

NASA Astrophysics Data System (ADS)

Kirkconnell, Carl S.; Ross, Bradley A.

2005-05-01

Raytheon has manufactured closed-cycle cryocoolers for both tactical military and space applications for over thirty years. Tactical and space cryocooler technologies have historically been treated as distinct both at Raytheon and throughout the industry. Differing technical requirements, operating lifetimes, and order quantities have driven these types of coolers to dramatically different design approaches and cost levels. For example, a typical space cryocooler system today costs approximately 2M as compared to roughly 10,000 for a tactical cryocooler. However, stimuli from both the tactical and space cooler user communities are driving the markets together. Tactical cryocooler requirements are starting to push towards operating lifetime requirements more characteristic of the space coolers (e.g., 20,000+ hours). Space cryocooler users, in particular Missile Defense Agency, are pushing for substantial cost reduction. In response, Raytheon is developing a low cost space cryocooler with an intended dual-use capability to also serve the tactical marketplace. This cooler leverages proven flexure-suspension technology to achieve long life, and a low cost concentric pulse tube cold head design has been developed that can be packaged into the existing Standard Advanced Dewar Assembly, Type One (SADA-I). The cooler meets or exceeds the SADA-I operational requirements (capacity, efficiency, etc.) as well. For the space-version of the cooler, the electronics cost has been reduced by an estimated 80% versus current designs, largely by approaching the vibration cancellation requirement from a dramatically different perspective. Fabrication of the brassboard expander is nearly complete, and the prototype design is well underway. The design approach, development progress, and proposed applications are presented.

Solar Effects on Tensile and Optical Properties of Hubble Space Telescope Silver-Teflon(Registered Trademark) Insulation

NASA Technical Reports Server (NTRS)

deGroh, Kim, K.; Dever, Joyce A.; Snyder, Aaron; Kaminski, Sharon; McCarthy, Catherine E.; Rapoport, Alison L.; Rucker, Rochelle N.

2006-01-01

A section of the retrieved Hubble Space Telescope (HST) solar array drive arm (SADA) multilayer insulation (MLI), which experienced 8.25 years of space exposure, was analyzed for environmental durability of the top layer of silver-Teflon (DuPont) fluorinated ethylene propylene (Ag-FEP). Because the SADA MLI had solar and anti-solar facing surfaces and was exposed to the space environment for a long duration, it provided a unique opportunity to study solar effects on the environmental degradation of Ag-FEP, a commonly used spacecraft thermal control material. Data obtained included tensile properties, solar absorptance, surface morphology and chemistry. The solar facing surface was found to be extremely embrittled and contained numerous through-thickness cracks. Tensile testing indicated that the solar facing surface lost 60% of its mechanical strength and 90% of its elasticity while the anti-solar facing surface had ductility similar to pristine FEP. The solar absorptance of both the solar facing surface (0.155 plus or minus 0.032) and the anti-solar facing surface (0.208 plus or minus 0.012) were found to be greater than pristine Ag-FEP (0.074). Solar facing and anti-solar facing surfaces were microscopically textured, and locations of isolated contamination were present on the anti-solar surface resulting in increased localized texturing. Yet, the overall texture was significantly more pronounced on the solar facing surface indicating a synergistic effect of combined solar exposure and increased heating with atomic oxygen erosion. The results indicate a very strong dependence of degradation, particularly embrittlement, upon solar exposure with orbital thermal cycling having a significant effect.

Erratum: "A Smaller Radius for the Transiting Exoplanet WASP-10b" (2009, ApJ, 692, L100)

NASA Astrophysics Data System (ADS)

Johnson, John Asher; Winn, Joshua N.; Cabrera, Nicole E.; Carter, Joshua A.

2010-03-01

We have identified an error in our Heliocentric Julian Dates (HJDs) of observation caused by incorrect input to the code used to convert from JD to HJD. The times in Table 1 have been corrected by adding 0.006382 day to each entry in the original Column 1. Similarly, the measured mid-transit time in Table 2 has been changed to Tc = 2454664.037295. We also note that the header in Column 1 of Table 1 is incorrect. The label should read HJD, rather than BJD. The updated Tables 1 and 2 have been included herein. This error has no impact on our main conclusions. We thank Pedro Valdes Sada and Gracjan Maciejewski for pointing out the incorrect mid-transit time.

Flap Edge Aeroacoustic Measurements and Predictions

NASA Technical Reports Server (NTRS)

Brooks, Thomas F.; Humphreys, William M., Jr.

2000-01-01

An aeroacoustic model test has been conducted to investigate the mechanisms of sound generation on high-lift wing configurations. This paper presents an analysis of flap side-edge noise, which is often the most dominant source. A model of a main element wing section with a half-span flap was tested at low speeds of up to a Mach number of 0.17, corresponding to a wing chord Reynolds number of approximately 1.7 million. Results are presented for flat (or blunt), flanged, and round flap-edge geometries, with and without boundary-layer tripping, deployed at both moderate and high flap angles. The acoustic database is obtained from a Small Aperture Directional Array (SADA) of microphones, which was constructed to electronically steer to different regions of the model and to obtain farfield noise spectra and directivity from these regions. The basic flap-edge aerodynamics is established by static surface pressure data, as well as by Computational Fluid Dynamics (CFD) calculations and simplified edge flow analyses. Distributions of unsteady pressure sensors over the flap allow the noise source regions to be defined and quantified via cross-spectral diagnostics using the SADA output. It is found that shear layer instability and related pressure scatter is the primary noise mechanism. For the flat edge flap, two noise prediction methods based on unsteady surface pressure measurements are evaluated and compared to measured noise. One is a new causality spectral approach developed here. The other is a new application of an edge-noise scatter prediction method. The good comparisons for both approaches suggest that much of the physics is captured by the prediction models. Areas of disagreement appear to reveal when the assumed edge noise mechanism does not fully define the noise production. For the different edge conditions, extensive spectra and directivity are presented. Significantly, for each edge configuration, the spectra for different flow speeds, flap angles, and

Flap Edge Aeroacoustic Measurements and Predictions

NASA Technical Reports Server (NTRS)

Brooks, Thomas F.; Humphreys, William M., Jr.

2000-01-01

An aeroacoustic model test has been conducted to investigate the mechanisms of sound generation on high-lift wing configurations. This paper presents an analysis of flap side-edge noise, which is often the most dominant source. A model of a main element wing section with a half-span flap was tested at low speeds of up to a Mach number of 0.17, corresponding to a wing chord Reynolds number of approximately 1.7 million. Results are presented for flat (or blunt), flanged, and round flap-edge geometries, with and without boundary-layer tripping, deployed at both moderate and high flap angles. The acoustic database is obtained from a Small Aperture Directional Array (SADA) of microphones, which was constructed to electronically steer to different regions of the model and to obtain farfield noise spectra and directivity from these regions. The basic flap-edge aerodynamics is established by static surface pressure data, as well as by Computational Fluid Dynamics (CFD) calculations and simplified edge flow analyses. Distributions of unsteady pressure sensors over the flap allow the noise source regions to be defined and quantified via cross-spectral diagnostics using the SADA output. It is found that shear layer instability and related pressure scatter is the primary noise mechanism. For the flat edge flap, two noise prediction methods based on unsteady-surface-pressure measurements are evaluated and compared to measured noise. One is a new causality spectral approach developed here. The other is a new application of an edge-noise scatter prediction method. The good comparisons for both approaches suggest that much of the physics is captured by the prediction models. Areas of disagreement appear to reveal when the assumed edge noise mechanism does not fully define, the noise production. For the different edge conditions, extensive spectra and directivity are presented. Significantly, for each edge configuration, the spectra for different flow speeds, flap angles, and

Velocity and vorticity measurements of Jupiter's Great Red Spot using automated cloud feature tracking

NASA Astrophysics Data System (ADS)

Choi, David S.; Banfield, Don; Gierasch, Peter; Showman, Adam P.

2007-05-01

We have produced mosaics of the Great Red Spot (GRS) using images taken by the Galileo spacecraft in May 2000, and have measured the winds of the GRS using an automated algorithm that does not require manual cloud tracking. Our technique yields a high-density, regular grid of wind velocity vectors that is advantageous over a limited number of scattered wind vectors that result from manual cloud tracking. The high-velocity collar of the GRS is clearly seen from our velocity vector map, and highest wind velocities are measured to be around 170 m s -1. The high resolution of the mosaics has also enabled us to map turbulent eddies inside the chaotic central region of the GRS, similar to those mapped by Sada et al. [Sada, P.V., Beebe, R.F., Conrath, B.J., 1996. Icarus 119, 311-335]. Using the wind velocity measurements, we computed particle trajectories around the GRS as well as maps of relative and absolute vorticities. We have discovered a narrow ring of cyclonic vorticity that surrounds the main anti-cyclonic high-velocity collar. This narrow ring appears to correspond to a ring surrounding the GRS that is bright in 5 μm [Terrile, R.J., Beebe, R.F., 1979. Science 204, 948-951]. It appears that this cyclonic ring is not a transient feature of the GRS, as we have discovered it in a re-analysis of Galileo data taken in 1996 first analyzed by Vasavada et al. [Vasavada, A.R., and 13 colleagues, 1998. Icarus 135, 265-275]. We also calculate how absolute vorticity changes as a function of latitude along a trajectory around the GRS and compare these measurements to similar ones performed by Dowling and Ingersoll [Dowling, T.E., Ingersoll, A.P., 1988. J. Atmos. Sci. 45, 1380-1396] using Voyager data. We show no dramatic evolution in the structure of the GRS since the Voyager era except for additional evidence for a counter-rotating GRS core, an increase in velocity in the main velocity collar, and an overall decrease in the length of the GRS.

Flap-edge aeroacoustic measurements and predictions

NASA Astrophysics Data System (ADS)

Brooks, Thomas F.; Humphreys, William M.

2003-03-01

An aeroacoustic model test has been conducted to investigate the mechanisms of sound generation on high-lift wing configurations. This paper presents an analysis of flap side-edge noise, which is often the most dominant source. A model of a main element wing section with a half-span flap was tested at low speeds of up to a Mach number of 0.17, corresponding to a wing chord Reynolds number of approximately 1.7 million. Results are presented for flat (or blunt), flanged, and round flap-edge geometries, with and without boundary-layer tripping, deployed at both moderate and high flap angles. The acoustic database is obtained from a small aperture directional array (SADA) of microphones, which was constructed to electronically steer to different regions of the model and to obtain farfield noise spectra and directivity from these regions. The basic flap-edge aerodynamics is established by static surface pressure data, as well as by computational fluid dynamics (CFD) calculations and simplified edge flow analyses. Distributions of unsteady pressure sensors over the flap allow the noise source regions to be defined and quantified via cross-spectral diagnostics using the SADA output. It is found that shear layer instability and related pressure scatter is the primary noise mechanism. For the flat edge flap, two noise prediction methods based on unsteady-surface-pressure measurements are evaluated and compared to measured noise. One is a new causality spectral approach developed here. The other is a new application of an edge-noise scatter prediction method. The good comparisons for both approaches suggest that the prediction models capture much of the physics. Areas of disagreement appear to reveal when the assumed edge noise mechanism does not fully define the noise production. For the different edge conditions, extensive spectra and directivity are presented. The complexity of the directivity results demonstrate the strong role of edge source geometry and frequency in

Development of a Coaxial Pulse Tube Cryocooler for 77 K Cooling

NASA Astrophysics Data System (ADS)

Olson, J. R.; Moore, M.; Evtimov, B.; Jensen, J.; Nast, T. C.

2006-04-01

Lockheed Martin's Advanced Technology Center has developed a compact coaxial pulse tube cryocooler for avionics applications. The cooler was designed to deliver in excess of 1W cooling at 77K with a heat rejection temperature of 70°C, and to cool down from ambient temperature in a very short period of time. The cryocooler utilizes our MINI compressor, developed for NASA-GSFC, coupled with a newly-designed coaxial pulse tube designed to approximate the Standard Advanced Dewar Assembly (SADA II) packaging envelope. The cryocooler mass is 1.25 kg. Test data show excellent performance, with cooldown times of less than 6 minutes (coldhead only, with no additional thermal mass attached to the coldhead). Performance data will be shown for a variety of operating conditions. A discussion of low cost pulse tube cryocoolers will also be presented. This cryocooler was developed and tested with Lockheed Martin IRAD funding.

Statistical mapping of zones of focused groundwater/surface-water exchange using fiber-optic distributed temperature sensing

USGS Publications Warehouse

Mwakanyamale, Kisa; Day-Lewis, Frederick D.; Slater, Lee D.

2013-01-01

Fiber-optic distributed temperature sensing (FO-DTS) increasingly is used to map zones of focused groundwater/surface-water exchange (GWSWE). Previous studies of GWSWE using FO-DTS involved identification of zones of focused GWSWE based on arbitrary cutoffs of FO-DTS time-series statistics (e.g., variance, cross-correlation between temperature and stage, or spectral power). New approaches are needed to extract more quantitative information from large, complex FO-DTS data sets while concurrently providing an assessment of uncertainty associated with mapping zones of focused GSWSE. Toward this end, we present a strategy combining discriminant analysis (DA) and spectral analysis (SA). We demonstrate the approach using field experimental data from a reach of the Columbia River adjacent to the Hanford 300 Area site. Results of the combined SA/DA approach are shown to be superior to previous results from qualitative interpretation of FO-DTS spectra alone.

Structural insight into the mechanism of synergistic autoinhibition of SAD kinases

PubMed Central

Wu, Jing-Xiang; Cheng, Yun-Sheng; Wang, Jue; Chen, Lei; Ding, Mei; Wu, Jia-Wei

2015-01-01

The SAD/BRSK kinases participate in various important life processes, including neural development, cell cycle and energy metabolism. Like other members of the AMPK family, SAD contains an N-terminal kinase domain followed by the characteristic UBA and KA1 domains. Here we identify a unique autoinhibitory sequence (AIS) in SAD kinases, which exerts autoregulation in cooperation with UBA. Structural studies of mouse SAD-A revealed that UBA binds to the kinase domain in a distinct mode and, more importantly, AIS nestles specifically into the KD-UBA junction. The cooperative action of AIS and UBA results in an ‘αC-out' inactive kinase, which is conserved across species and essential for presynaptic vesicle clustering in C. elegans. In addition, the AIS, along with the KA1 domain, is indispensable for phospholipid binding. Taken together, these data suggest a model for synergistic autoinhibition and membrane activation of SAD kinases. PMID:26626945

Structural insight into the mechanism of synergistic autoinhibition of SAD kinases.

PubMed

Wu, Jing-Xiang; Cheng, Yun-Sheng; Wang, Jue; Chen, Lei; Ding, Mei; Wu, Jia-Wei

2015-12-02

The SAD/BRSK kinases participate in various important life processes, including neural development, cell cycle and energy metabolism. Like other members of the AMPK family, SAD contains an N-terminal kinase domain followed by the characteristic UBA and KA1 domains. Here we identify a unique autoinhibitory sequence (AIS) in SAD kinases, which exerts autoregulation in cooperation with UBA. Structural studies of mouse SAD-A revealed that UBA binds to the kinase domain in a distinct mode and, more importantly, AIS nestles specifically into the KD-UBA junction. The cooperative action of AIS and UBA results in an 'αC-out' inactive kinase, which is conserved across species and essential for presynaptic vesicle clustering in C. elegans. In addition, the AIS, along with the KA1 domain, is indispensable for phospholipid binding. Taken together, these data suggest a model for synergistic autoinhibition and membrane activation of SAD kinases.

Aeroacoustic Measurements of a Wing/Slat Model

NASA Astrophysics Data System (ADS)

Mendoza, Jeff M.; Brooks, Thomas F.; Humphreys, William M.

2002-01-01

Aeroacoustic evaluations of high-lift devices have been carried out in the Quiet Flow Facility of the NASA Langley Research Center. The present paper deals with detailed flow and acoustic measurements that have been made to understand, and to possibly predict and reduce, the noise from a wing leading edge slat configuration. The acoustic database is obtained by a moveable Small Aperture Directional Array (SADA) of microphones designed to electronically steer to different portions of models under study. The slat is shown to be a uniform distributed noise source. The data was processed such that spectra and directivity were determined with respect to a one-foot span of slat. The spectra are normalized in various fashions to demonstrate slat noise character. In order to equate portions of the spectra to different slat noise components, trailing edge noise predictions using measured slat boundary layer parameters as inputs are compared to the measured slat noise spectra.

Aeroacoustic Measurements of a Wing/Slat Model. [Research conducted at the Quiet Flow Facility of the NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Mendoza, Jeff M.; Brooks, Thomas F.; Humphreys, William M.

2002-01-01

Aeroacoustic evaluations of high-lift devices have been carried out in the Quiet Flow Facility of the NASA Langley Research Center. The present paper deals with detailed flow and acoustic measurements that have been made to understand, and to possibly predict and reduce, the noise from a wing leading edge slat configuration. The acoustic database is obtained by a moveable Small Aperture Directional Array (SADA) of microphones designed to electronically steer to different portions of models under study. The slat is shown to be a uniform distributed noise source. The data was processed such that spectra and directivity were determined with respect to a one-foot span of slat. The spectra are normalized in various fashions to demonstrate slat noise character. In order to equate portions of the spectra to different slat noise components, trailing edge noise predictions using measured slat boundary layer parameters as inputs are compared to the measured slat noise spectra.

SAD kinases sculpt axonal arbors of sensory neurons through long and short-term responses to neurotrophin signals

PubMed Central

Lilley, Brendan N.; Pan, Y. Albert; Sanes, Joshua R.

2013-01-01

SUMMARY Extrinsic cues activate intrinsic signaling mechanisms to pattern neuronal shape and connectivity. We showed previously that three cytoplasmic Ser/Thr kinases, LKB1, SAD-A and SAD-B, control early axon-dendrite polarization in forebrain neurons. Here we assess their role in other neuronal types. We found that all three kinases are dispensable for axon formation outside of the cortex, but that SAD kinases are required for formation of central axonal arbors by subsets of sensory neurons. The requirement for SAD kinases is most prominent in NT-3 dependent neurons. SAD kinases transduce NT-3 signals in two ways through distinct pathways. First, sustained NT-3/TrkC signaling increases SAD protein levels. Second, short duration NT-3/TrkC signals transiently activate SADs by inducing dephosphorylation of C-terminal domains, thereby allowing activating phosphorylation of the kinase domain. We propose that SAD kinases integrate long- and short duration signals from extrinsic cues to sculpt axon arbors within the CNS. PMID:23790753

Tactical versus space cryocoolers: a comparision

NASA Astrophysics Data System (ADS)

Arts, R.; Mullié, J.; Leenders, H.; de Jonge, G.; Benschop, T.

2017-05-01

In recent years, several space cryocooler developments have been performed in parallel at Thales Cryogenics. On one end of the spectrum are research programmes such as the ESA-funded 30-50 K system developed in cooperation with CEA and Absolut System and the LPT6510 cooler developed in cooperation with Absolut System. On the other end of the spectrum are commercial designs adapted for space applications, such as the LPT9310 commercial coolers delivered for JPL's ECOSTRESS instrument and the LSF9199/30 SADA-compatible cooler delivered for various space programmes at Sofradir. In this paper, an overview is presented of the latest developments regarding these coolers. Initial performance results of the 30-50K cooler are discussed, pending developments for the LPT6510 cooler are presented, and the synergies between COTS and space are reviewed, such as design principles from space coolers being applied to an upgraded variant of the COTS LPT9310, as well as design principles from COTS coolers being applied to the LPT6510 for improved manufacturability.

SAD kinases sculpt axonal arbors of sensory neurons through long- and short-term responses to neurotrophin signals.

PubMed

Lilley, Brendan N; Pan, Y Albert; Sanes, Joshua R

2013-07-10

Extrinsic cues activate intrinsic signaling mechanisms to pattern neuronal shape and connectivity. We showed previously that three cytoplasmic Ser/Thr kinases, LKB1, SAD-A, and SAD-B, control early axon-dendrite polarization in forebrain neurons. Here, we assess their role in other neuronal types. We found that all three kinases are dispensable for axon formation outside of the cortex but that SAD kinases are required for formation of central axonal arbors by subsets of sensory neurons. The requirement for SAD kinases is most prominent in NT-3 dependent neurons. SAD kinases transduce NT-3 signals in two ways through distinct pathways. First, sustained NT-3/TrkC signaling increases SAD protein levels. Second, short-duration NT-3/TrkC signals transiently activate SADs by inducing dephosphorylation of C-terminal domains, thereby allowing activating phosphorylation of the kinase domain. We propose that SAD kinases integrate long- and short-duration signals from extrinsic cues to sculpt axon arbors within the CNS. Copyright © 2013 Elsevier Inc. All rights reserved.

Second-generation detector work in Israel

NASA Astrophysics Data System (ADS)

Rosenfeld, David

2001-10-01

A tremendous developmental effort in the field of infrared detectors during the last decade in Israel has resulted in a variety of InSb and HgCdTe infrared detectors. Additional and significant R&D effort associated with other IR components, have also been done in Israel, in order to integrate the detectors into advanced Detector-Dewar-Cooler assemblies (DDCs). This R&D effort included notable activities in the field of materials, signal processors, dewars and cryocoolers. These activities are presented together with the status of infrared detector work in Israel. Several two-dimensional InSb staring detectors and DDCs are demonstrated. This includes two versions of the classical 256 X 256 detectors and DDCs, improved 640 X 480 InSb detectors and DDC, and a 2000- element detector with high TDI level. SADA II type HgCdTe detectors are also presented. Considerations regarding the course of future detector work are also described. The classical DDC requirement list which traditionally included demands for high D*, low NETD and high resolution is widened to include cost related issues such as higher reliability, lower maintenance, smaller volume, lower power consumption and higher operation temperature.

Producibility of Vertically Integrated Photodiode (VIP)tm scanning focal plane arrays

NASA Astrophysics Data System (ADS)

Turner, Arthur M.; Teherani, Towfik; Ehmke, John C.; Pettitt, Cindy; Conlon, Peggy; Beck, Jeffrey D.; McCormack, Kent; Colombo, Luigi; Lahutsky, Tom; Murphy, Terry; Williams, Robert L.

1994-07-01

Vertically integrated photodiode, VIPTM, technology is now being used to produce second generation infrared focal plane arrays with high yields and performance. The VIPTM process employs planar, ion implanted, n on p diodes in HgCdTe which is epoxy hybridized directly to the read out integrated circuits on 100 mm Si wafers. The process parameters that are critical for high performance and yield include: HgCdTe dislocation density and thickness, backside passivation, frontside passivation, and junction formation. Producibility of infrared focal plane arrays (IRFPAs) is also significantly enhanced by read out integrated circuits (ROICs) which have the ability to deselect defective pixels. Cold probe screening before lab dewar assembly reduces costs and improves cycle times. The 240 X 1 and 240 X 2 scanning array formats are used to demonstrate the effect of process optimization, deselect, and cold probe screening on yield and cycle time. The versatility of the VIPTM technology and its extension to large area arrays is demonstrated using 240/288 X 4 and 480 X 5 TDI formats. Finally, the high performance of VIPTM IRFPAs is demonstrated by comparing data from a 480 X 5 to the SADA-II specification.

INSAT-3D: an advanced meteorological mission over Indian Ocean

NASA Astrophysics Data System (ADS)

Katti, V. R.; Pratap, V. R.; Dave, R. K.; Mankad, K. N.

2006-12-01

This paper presents the salient features of INSAT 3D mission and its Met Payloads. INSAT-3D, the next ISRO meteorological satellite aims for a significant technological improvement in sensor capabilities as compared to earlier INSAT missions. It is an exclusive mission designed for enhanced meteorological observations and monitoring of land and ocean surfaces for weather forecasting and disaster warning. The three-axis stabilized geostationary satellite is to carry two meteorological instruments: a six channel Imager and an IR Sounder. Along with the channels in Visible, Middle Infrared, Water Vapor and Thermal Infrared bands, the Imager includes a SWIR channel for wider applications. The Sounder will have eighteen narrow spectral channels in three IR bands in addition to a channel in visible band. INSAT-3D is configured around standard 2000 kg I2K spacecraft bus with 7-year life. Several innovative technologies like on-the-fly correction of scan mirror pointing errors, biannual yaw rotation of the spacecraft, micro-stepping SADA, star sensors and integrated bus management unit have been incorporated to meet the stringent payload requirements like pointing accuracies, thermal management of IR detectors and concurrent operation of both instruments.

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT, ENVIRONMENTAL DECISION SUPPORT SOFTWARE, UNIVERSITY OF TENNESSEE RESEARCH CORPORATION, SPATIAL ANALYSIS AND DECISION ASSISTANCE (SADA)

EPA Science Inventory

The U.S. Environmental Protection Agency (EPA) has created the Environmental Technology Verification Program (ETV) to facilitate the deployment of innovative or improved environmental technologies through performance verification and dissemination of information. The goal of the...

Trial Burn Plan for a Transportable Incineration System (TIS) at the Savanna Army Depot Activity (SADA) Washout Lagoon Area

DTIC Science & Technology

1991-11-27

the methylene chloride/methanol mix. All test train components will be composited and explosives will be analyzed and reported on a total test train...check ute volume metering system nicked. dented. or cored . they Shall be note the barometric preure. nd the ulibration values ax the field test site...antimony, arsenic, cadmium, lead, selenium, thallium hollow cathode lamps (HCLs) or electrodeless discharge lamps (EDLs). [Same as EPA SW-846 Methods 7041

Wideband RELAX and wideband CLEAN for aeroacoustic imaging

NASA Astrophysics Data System (ADS)

Wang, Yanwei; Li, Jian; Stoica, Petre; Sheplak, Mark; Nishida, Toshikazu

2004-02-01

Microphone arrays can be used for acoustic source localization and characterization in wind tunnel testing. In this paper, the wideband RELAX (WB-RELAX) and the wideband CLEAN (WB-CLEAN) algorithms are presented for aeroacoustic imaging using an acoustic array. WB-RELAX is a parametric approach that can be used efficiently for point source imaging without the sidelobe problems suffered by the delay-and-sum beamforming approaches. WB-CLEAN does not have sidelobe problems either, but it behaves more like a nonparametric approach and can be used for both point source and distributed source imaging. Moreover, neither of the algorithms suffers from the severe performance degradations encountered by the adaptive beamforming methods when the number of snapshots is small and/or the sources are highly correlated or coherent with each other. A two-step optimization procedure is used to implement the WB-RELAX and WB-CLEAN algorithms efficiently. The performance of WB-RELAX and WB-CLEAN is demonstrated by applying them to measured data obtained at the NASA Langley Quiet Flow Facility using a small aperture directional array (SADA). Somewhat surprisingly, using these approaches, not only were the parameters of the dominant source accurately determined, but a highly correlated multipath of the dominant source was also discovered.

Wideband RELAX and wideband CLEAN for aeroacoustic imaging.

PubMed

Wang, Yanwei; Li, Jian; Stoica, Petre; Sheplak, Mark; Nishida, Toshikazu

2004-02-01

Microphone arrays can be used for acoustic source localization and characterization in wind tunnel testing. In this paper, the wideband RELAX (WB-RELAX) and the wideband CLEAN (WB-CLEAN) algorithms are presented for aeroacoustic imaging using an acoustic array. WB-RELAX is a parametric approach that can be used efficiently for point source imaging without the sidelobe problems suffered by the delay-and-sum beamforming approaches. WB-CLEAN does not have sidelobe problems either, but it behaves more like a nonparametric approach and can be used for both point source and distributed source imaging. Moreover, neither of the algorithms suffers from the severe performance degradations encountered by the adaptive beamforming methods when the number of snapshots is small and/or the sources are highly correlated or coherent with each other. A two-step optimization procedure is used to implement the WB-RELAX and WB-CLEAN algorithms efficiently. The performance of WB-RELAX and WB-CLEAN is demonstrated by applying them to measured data obtained at the NASA Langley Quiet Flow Facility using a small aperture directional array (SADA). Somewhat surprisingly, using these approaches, not only were the parameters of the dominant source accurately determined, but a highly correlated multipath of the dominant source was also discovered.

The long and the short of SAD-1 kinase.

PubMed

Kim, Joanne S M; Hung, Wesley; Zhen, Mei

2010-05-01

The Ser/Thr SAD kinases are evolutionarily conserved, critical regulators of neural development. Exciting findings in recent years have significantly advanced our understanding of the mechanism through which SAD kinases regulate neural development. Mammalian SAD-A and SAD-B, activated by a master kinase LKB1, regulate microtubule dynamics and polarize neurons. In C. elegans, the sad-1 gene encodes two isoforms, namely the long and the short, which exhibit overlapping and yet distinct functions in neuronal polarity and synaptic organization. Surprisingly, our most recent findings in C. elegans revealed a SAD-1-independent LKB1 activity in neuronal polarity. We also found that the long SAD-1 isoform directly interacts with a STRADalpha pseudokinase, STRD-1, to regulate neuronal polarity and synaptic organization. We elaborate here a working model of SAD-1 in which the two isoforms dimer/oligomerize to form a functional complex, and STRD-1 clusters and localizes the SAD-1 complex to synapses. While the mechanistic difference between the vertebrate and invertebrate SAD kinases may be puzzling, a recent discovery of the functionally distinct SAD-B isoforms predicts that the difference likely arises from our incomplete understanding of the SAD kinase mechanism and may eventually be reconciled as the revelation continues.

The pea SAD short-chain dehydrogenase/reductase: quinone reduction, tissue distribution, and heterologous expression.

PubMed

Scherbak, Nikolai; Ala-Häivälä, Anneli; Brosché, Mikael; Böwer, Nathalie; Strid, Hilja; Gittins, John R; Grahn, Elin; Eriksson, Leif A; Strid, Åke

2011-04-01

The pea (Pisum sativum) tetrameric short-chain alcohol dehydrogenase-like protein (SAD) family consists of at least three highly similar members (SAD-A, -B, and -C). According to mRNA data, environmental stimuli induce SAD expression. The aim of this study was to characterize the SAD proteins by examining their catalytic function, distribution in pea, and induction in different tissues. In enzyme activity assays using a range of potential substrates, the SAD-C enzyme was shown to reduce one- or two-ring-membered quinones lacking long hydrophobic hydrocarbon tails. Immunological assays using a specific antiserum against the protein demonstrated that different tissues and cell types contain small amounts of SAD protein that was predominantly located within epidermal or subepidermal cells and around vascular tissue. Particularly high local concentrations were observed in the protoderm of the seed cotyledonary axis. Two bow-shaped rows of cells in the ovary and the placental surface facing the ovule also exhibited considerable SAD staining. Ultraviolet-B irradiation led to increased staining in epidermal and subepidermal cells of leaves and stems. The different localization patterns of SAD suggest functions both in development and in responses to environmental stimuli. Finally, the pea SAD-C promoter was shown to confer heterologous wound-induced expression in Arabidopsis (Arabidopsis thaliana), which confirmed that the inducibility of its expression is regulated at the transcriptional level.

The Pea SAD Short-Chain Dehydrogenase/Reductase: Quinone Reduction, Tissue Distribution, and Heterologous Expression1[W][OA

PubMed Central

Scherbak, Nikolai; Ala-Häivälä, Anneli; Brosché, Mikael; Böwer, Nathalie; Strid, Hilja; Gittins, John R.; Grahn, Elin; Eriksson, Leif A.; Strid, Åke

2011-01-01

The pea (Pisum sativum) tetrameric short-chain alcohol dehydrogenase-like protein (SAD) family consists of at least three highly similar members (SAD-A, -B, and -C). According to mRNA data, environmental stimuli induce SAD expression. The aim of this study was to characterize the SAD proteins by examining their catalytic function, distribution in pea, and induction in different tissues. In enzyme activity assays using a range of potential substrates, the SAD-C enzyme was shown to reduce one- or two-ring-membered quinones lacking long hydrophobic hydrocarbon tails. Immunological assays using a specific antiserum against the protein demonstrated that different tissues and cell types contain small amounts of SAD protein that was predominantly located within epidermal or subepidermal cells and around vascular tissue. Particularly high local concentrations were observed in the protoderm of the seed cotyledonary axis. Two bow-shaped rows of cells in the ovary and the placental surface facing the ovule also exhibited considerable SAD staining. Ultraviolet-B irradiation led to increased staining in epidermal and subepidermal cells of leaves and stems. The different localization patterns of SAD suggest functions both in development and in responses to environmental stimuli. Finally, the pea SAD-C promoter was shown to confer heterologous wound-induced expression in Arabidopsis (Arabidopsis thaliana), which confirmed that the inducibility of its expression is regulated at the transcriptional level. PMID:21343423

On the development of co-axial miniature pulse tube coolers for space applications

NASA Astrophysics Data System (ADS)

Zhou, Y.; Liang, J. T.; Zhu, W. Q.; Cai, J. H.; Ju, Y. L.

2002-05-01

Cryocoolers for cooling infrared sensors in space applications require high reliability, long lifetime, low power and minimum weight. In this paper we report work on a miniature pulse tube cooler specifically designed for such applications. A series of engineering model co-axial miniature pulse tube coolers with a flexure bearing linear compressor of 1 cc swept volume have been designed and fabricated in our laboratory. A theoretical model is established based on the analyses of thermodynamic and hydrodynamic behaviors of oscillatory flows in regenerator, for performance prediction, optimization and as a rough guide in the early stages of system design. An experimental apparatus, including a hot wire anemometer, has been set up to study the flow resistance of regenerators under oscillatory flow conditions. The co-axial, multi-bypass, and symmetric nozzle structure has been used in the coolers. We will present here the performance of two sizes of coolers with 9 mm and 8 mm diameter of cold fingers. The 9 mm cooler currently provides 500 mW net cooling power at 80 K with input power of 47 W, and the 8 mm cooler, provides 450 mW at 80 K with 51 W input power with a 65% efficient compressor. The cold fingers of our co-axial pulse tube coolers have the similar size of miniature Stirling coolers and are the only one that could meet the geometry specifications of the Standard Advance Dewar Assembly (SADA) for thermal imaging systems in most military applications.

Evaluation of cardioprotective effect of silk cocoon (Abresham) on isoprenaline-induced myocardial infarction in rats.

PubMed

Srivastav, Ritesh Kumar; Siddiqui, Hefazat Hussain; Mahmood, Tarique; Ahsan, Farogh

2013-01-01

The study was conducted to evaluate cardioprotective effect of silk cocoon (Abresham) Bombyx mori (B. mori) on isoprenaline-induced myocardial infarction. This study deals with the cocoons, which is called Abresham in the Unani system of medicine. It is one of the 64 drugs which Avicenna has mentioned in Avicenna's tract on cardiac drugs and used in the treatment of cardiovascular diseases. Abresham is a chief ingredient of the two very famous Unani formulation viz. Khamira Abresham Sada, and Khamira Abresham Hakim Arshad Wala. The ethanolic extract of B. mori (Abresham) silk cocoons in the dose of 250 mg/kg and 500 mg/kg body weight was administered orally for 28 days before isoprenaline administration to test their cardioprotective effect. Isoprenaline (85 mg/kg) was administered subcutaneously on days 29(th) and 30(th), respectively in order to induce myocardial infarction. The parameters for evaluation of cardioprotective activity were the physical parameters and the biochemical estimations. The physical parameters were gross examination of heart, heart weight/body weight ratio and histopathology examination. In biochemical estimations, the activity of various cardiac enzymes such as aspartate transaminase, alanine transaminase, creatinine kinase, lactate dehydrogenase, and the gold marker troponin-I were determined. The levels altered by isoproterenol were restored significantly by the administration of the both doses of test extract especially at higher dose. The result of this study shows that alcoholic extract B. mori has significant cardioprotective activity against isoprenaline-induced myocardial infarction.

Site Safety and Health Plan (SSHP) for a Transportable Incineration System (TIS) at the Savanna Army Depot Activity (SADA), Washout Lagoon Area. Appendices

DTIC Science & Technology

1991-03-08

on rates of death by cancer, funded by the Nuclear Regulatory Commission 1977 - 1978 - Special Consultant to Assistant Secretary for Health... BY LIFTING THE CHIN. PASS TUBE OVER TONGUE AND TOWARD BACK OF THROAT WITHOUT EXTENDING HEAD OR NECK. IF OBSTRUCTION IS MET BEFORE THE MARK ON TUBE...COMPENSATION, AND LIABILITY ACT OF 1980 (CERCLA) BY EXHIBITING ONE OR MORE OF THE CHARACTERISTICS OF IGNITABILITY,

Smokeless tobacco and public health in Bangladesh.

PubMed

Huque, Rumana; Zaman, M Mostafa; Huq, Syed Mahfuzul; Sinha, Dhirendra N

2017-09-01

Despite the high prevalence of smokeless tobacco (SLT) use among adults in Bangladesh, SLT was not included in the Tobacco Control Law till 2013. Information on SLT use among Bangladeshi people is inadequate for policymaking and implementing effective control measures. With the aim to identify the prevalence and trends of different SLT products, health and economic impacts, manufacture, and sale of and policies related to SLT in Bangladesh, we carried out a literature review, which involved literature search, data extraction, and synthesis. Evidence suggests that in Bangladesh, SLTs range from unprocessed to processed or manufactured products including Sada Pata, Zarda, Gul, and Khoinee. Over 27% of Bangladeshi adults aged 15 years and older use SLT in one form or other. SLT use is associated with age, sex, education, and socioeconomic status. SLT consumption has reportedly been associated with increased prevalence of heart diseases, stroke, and oral cancer and led to around 320,000 disability adjusted life years lost in Bangladesh in 2010. No cessation service is available for SLT users in public facilities. Compared to cigarettes, taxation on SLT remains low in Bangladesh. The amendment made in Tobacco Control Law in 2013 requires graphic health warnings to cover 50% of SLT packaging, ban on advertisement of SLT products, and restriction to sale to minors. However, implementation of the law is weak. As the use of SLT is culturally accepted in Bangladesh, culturally appropriate public awareness program is required to curb SLT use along with increased tax and cessation services.

Advances in Current Rating Techniques for Flexible Printed Circuits

NASA Technical Reports Server (NTRS)

Hayes, Ron

2014-01-01

Twist Capsule Assemblies are power transfer devices commonly used in spacecraft mechanisms that require electrical signals to be passed across a rotating interface. Flexible printed circuits (flex tapes, see Figure 2) are used to carry the electrical signals in these devices. Determining the current rating for a given trace (conductor) size can be challenging. Because of the thermal conditions present in this environment the most appropriate approach is to assume that the only means by which heat is removed from the trace is thru the conductor itself, so that when the flex tape is long the temperature rise in the trace can be extreme. While this technique represents a worst-case thermal situation that yields conservative current ratings, this conservatism may lead to overly cautious designs when not all traces are used at their full rated capacity. A better understanding of how individual traces behave when they are not all in use is the goal of this research. In the testing done in support of this paper, a representative flex tape used for a flight Solar Array Drive Assembly (SADA) application was tested by energizing individual traces (conductors in the tape) in a vacuum chamber and the temperatures of the tape measured using both fine-gauge thermocouples and infrared thermographic imaging. We find that traditional derating schemes used for bundles of wires do not apply for the configuration tested. We also determine that single active traces located in the center of a flex tape operate at lower temperatures than those on the outside edges.

Thermal Infrared Frontiers

NASA Astrophysics Data System (ADS)

Jennings, D. E.

2002-05-01

The solar spectrum between 5 and 28 microns has a rich diagnostic potential that is only now being realized. The ATST will have instrumentation specialized for this ``thermal" infrared region that will go well beyond present capabilities for solar magnetic field research. In particular, the MgI emission lines near 12 microns offer advantages for polarimetry. The Zeeman splittings in these lines are completely resolved at field strengths of a few hundred gauss. These lines are formed in the upper photosphere and, when used with data from the visible and near-infrared, produce three-dimensional pictures of the magnetic field. During the past two years, a team from Goddard Space Flight Center has been mapping vector fields in Stokes IQUV using a cryogenic grating spectrometer and a 12-micron polarization analyzer at the McMath-Pierce Telescope. On 24 April 2001 active region NOAA 9433 was mapped just before an M2 flare, revealing opposite polarity fields of 2700 and 1000 G within a single 2 arcsec pixel and implying a very high 5 G/km horizontal field gradient prior to the flare (1). In addition to polarimetry, there are advantages for imaging in the thermal infrared. The continuum brightness is a direct measure of temperature, and probes heights from 50 to 250 km at progressively longer wavelengths. The ATST will take advantage of the low light scattering and negligible instrumental polarization in the infrared, and will minimize thermal background. The large aperture of the ATST will produce unprecedented diffraction-limited spatial resolution at infrared wavelengths. This work is supported in part by NASA's Solar and Heliospheric Physics Program. (1) Jennings, D.E., Deming, D., McCabe, G., Sada, P.V., and Moran, T. 2002, ApJ, 568, April 1, to be published.

Velocity and Vorticity Measurements of Jupiter's Great Red Spot Using Automated Cloud Feature Trackers

NASA Astrophysics Data System (ADS)

Choi, David S.; Banfield, D.; Gierasch, P. J.; Showman, A. P.

2006-09-01

We have produced mosaics of the Great Red Spot (GRS) using images taken by Galileo in May 2000, and have measured the winds of the GRS using an automated algorithm that does not require manual cloud tracking. Our technique yields a high-density, regular grid of wind velocity vectors that is advantageous over a limited number of scattered wind vectors that result from manual cloud tracking. The high-velocity collar of the GRS is clearly seen in our velocity vector map, and highest wind velocities are measured to be 166.4 m/s. The high resolution of the mosaics have also enabled us to map turbulent eddies inside the chaotic central region of the GRS, similar to those mapped by Sada et al. (1996) and Vasavada et al. (1998). We have also discovered a narrow ring of cyclonic vorticity that surrounds the main anti-cyclonic high-velocity collar. This narrow ring appears to correspond to a ring surrounding the GRS that is bright in 5-um (Terrile et al. 1979). It appears that this cyclonic ring is not a transient feature of the GRS, as we have discovered it in a re-analysis of Galileo images from 1996, first analyzed by Vasavada et al. (1998). Cyclonic rings around Jovian anti-cyclones have also appeared in numerical modeling studies by Showman (2006). We also calculate how absolute vorticity changes as a function of latitude along particle trajectories around the GRS and compare these measurements to similar ones performed by Dowling & Ingersoll (1988) using Voyager data. From this comparison, we show no dramatic evolution in the structure of the GRS since the Voyager era. This work was supported by NASA Planetary Atmospheres grants to APS and PJG, along with support from Cornell Presidential Research Scholars.

Effect of crude extract of Bombyx mori coccoons in hyperlipidemia and atherosclerosis

PubMed Central

Ali, Mir Mahdi; Arumugam, Sarasa Bharati A.

2011-01-01

The silkworm is the larva or caterpillar of the domesticated silkmoth, Bombyx mori and being a primary producer of silk is an economically important insect. These days the silk is emerging as a resource for solving a broad range of biological problems. The silk (Abresham) is popularly known as Abresham muqriz (muqriz means cut) in Unani medicine. Its cocoons are extensively used as an ingredient of various Unani formulations like Khameer-E- Abresham Sada, Khameere Abresham Hakeem Arshad Wala, Khameere Abresham Ood Mastagi Wala etc. and are used to treat many cardiac and nervous disorders. The hypolipidemic activity of this drug, along with Nepata Hindostana (Badranjboya) and Terminalia Arjuna (Arjan) has been documented. But action of extract of Bombyx mori cocoons as a single drug is not documented. That's why; it was decided to study its effect on hyperlipidemia and atherosclerosis. The Male New Zealand White rabbits all of 1.5kgs were selected for the study. After stabilization period (2 weeks) the rabbits were divided into 3 groups (Group I - Control, Group II Lesion Control and Group III treated with extract of Bombyx mori silk cocoon). Hyperlipidemia and atherosclerosis were induced with 1% cholesterol diet. After induction of hyperlipidemia and atherosclerosis for twelve weeks, Group III rabbits were treated with Bombyx mori for 6 weeks (45 days). A significant decrease in hyperlipidemia was seen within 4 weeks of treatment. Histopathologically, the atherosclerotic plaques showed reduction in size. The third group showed a significant increase in the body weight and also an increase in the HDL cholesterol levels. The study concludes that extract of Bombyx mori cocoons has a significant effect on hypercholesterolemia and atherosclerosis probably because of its antioxidant and hypolipidemic effect. PMID:21760692

Effect of crude extract of Bombyx mori coccoons in hyperlipidemia and atherosclerosis.

PubMed

Ali, Mir Mahdi; Arumugam, Sarasa Bharati A

2011-04-01

The silkworm is the larva or caterpillar of the domesticated silkmoth, Bombyx mori and being a primary producer of silk is an economically important insect. These days the silk is emerging as a resource for solving a broad range of biological problems. The silk (Abresham) is popularly known as Abresham muqriz (muqriz means cut) in Unani medicine. Its cocoons are extensively used as an ingredient of various Unani formulations like Khameer-E- Abresham Sada, Khameere Abresham Hakeem Arshad Wala, Khameere Abresham Ood Mastagi Wala etc. and are used to treat many cardiac and nervous disorders. The hypolipidemic activity of this drug, along with Nepata Hindostana (Badranjboya) and Terminalia Arjuna (Arjan) has been documented. But action of extract of Bombyx mori cocoons as a single drug is not documented. That's why; it was decided to study its effect on hyperlipidemia and atherosclerosis. The Male New Zealand White rabbits all of 1.5kgs were selected for the study. After stabilization period (2 weeks) the rabbits were divided into 3 groups (Group I - Control, Group II Lesion Control and Group III treated with extract of Bombyx mori silk cocoon). Hyperlipidemia and atherosclerosis were induced with 1% cholesterol diet. After induction of hyperlipidemia and atherosclerosis for twelve weeks, Group III rabbits were treated with Bombyx mori for 6 weeks (45 days). A significant decrease in hyperlipidemia was seen within 4 weeks of treatment. Histopathologically, the atherosclerotic plaques showed reduction in size. The third group showed a significant increase in the body weight and also an increase in the HDL cholesterol levels. The study concludes that extract of Bombyx mori cocoons has a significant effect on hypercholesterolemia and atherosclerosis probably because of its antioxidant and hypolipidemic effect.

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

PubMed Central

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

2015-01-01

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

An innovative deployable solar panel system for Cubesats

NASA Astrophysics Data System (ADS)

Santoni, Fabio; Piergentili, Fabrizio; Donati, Serena; Perelli, Massimo; Negri, Andrea; Marino, Michele

2014-02-01

One of the main Cubesat bus limitations is the available on-board power. The maximum power obtained using body mounted solar panels and advanced triple junction solar cells on a triple unit Cubesat is typically less than 10 W. The Cubesat performance and the mission scenario opened to these small satellite systems could be greatly enhanced by an increase of the available power. This paper describes the design and realization of a modular deployable solar panel system for Cubesats, consisting of a modular hinge and spring system that can be potentially used on-board single (1U), double(2U), triple (3U) and six units (6U) Cubesats. The size of each solar panels is the size of a lateral Cubesat surface. The system developed is the basis for a SADA (Solar Array Drive Assembly), in which a maneuvering capability is added to the deployed solar array in order to follow the apparent motion of the sun. The system design trade-off is discussed, comparing different deployment concepts and architectures, leading to the final selection for the modular design. A prototype of the system has been realized for a 3U Cubesat, consisting of two deployable solar panel systems, made of three solar panels each, for a total of six deployed solar panels. The deployment system is based on a plastic fiber wire and thermal cutters, guaranteeing a suitable level of reliability. A test-bed for the solar panel deployment testing has been developed, supporting the solar array during deployment reproducing the dynamical situation in orbit. The results of the deployment system testing are discussed, including the design and realization of the test-bed, the mechanical stress given to the solar cells by the deployment accelerations and the overall system performance. The maximum power delivered by the system is about 50.4 W BOL, greatly enhancing the present Cubesat solar array performance.

Ground based Mid-IR Observations of Temporally Varying Ethylene Emission on Jupiter

NASA Astrophysics Data System (ADS)

Romani, P. N.; Jennings, D. E.; Bjoraker, G. L.; Sada, P. V.; Boyle, R.; McCabe, G.

2003-05-01

Ethylene (C2H4)is an important species in our understanding of hydrocarbon photochemistry in the atmospheres of the giant planets. It also provides a sensitive probe of conditions at the 10-microbar level in Jupiter's atmosphere, a region that is strongly influenced by aurora. We performed high-resolution spectral observations of C2H4 at 10.53 microns (949.5 cm-1) on Jupiter with Celeste, a Goddard-developed cryogenic echelle spectrometer, during October-November 1998 at the McMath-Pierce telescope of the National Solar Observatory at Kitt Peak and during June 2000 at the IRTF at Mt. Kea in Hawai'i. We observed C2H4 line emission in the equatorial region and enhanced emission in the auroral latitudes. We modeled the emission using photochemical model profiles and either multiplied the model profile by a constant factor, adjusted the temperature in the isothermal region of the atmosphere, or adjusted the pressure level where the large thermal gradient starts. Analysis of the southern and northern auroral region emission yielded similar results with the exception of one day (21 June 2000) in the northern hemisphere "hot spot: (LIII 180 degrees). On this day the C2H4 emission was exceptionally bright. To match the emission required either multiplying the photochemical model profile by 25, or increasing the isothermal region temperature from 168K to 261K, or lowering the start of the temperature gradient region to 0.055 mbar. Of these three possibilities the increase in C2H4 abundance profile provided the poorest fit. Since the C2H4 emission on either side of this day was lower, and similar to each other, whatever mechanism that caused the increase in emission had to "turn on and off" within 48 hours. Similar short term behavior has been seen with Cassini-CIRS (see abstract by Sada et al.) This work is supported by the NASA Planetary Astronomy Program.

Adaptive Jacobian Fuzzy Attitude Control for Flexible Spacecraft Combined Attitude and Sun Tracking System

NASA Astrophysics Data System (ADS)

Chak, Yew-Chung; Varatharajoo, Renuganth

2016-07-01

Many spacecraft attitude control systems today use reaction wheels to deliver precise torques to achieve three-axis attitude stabilization. However, irrecoverable mechanical failure of reaction wheels could potentially lead to mission interruption or total loss. The electrically-powered Solar Array Drive Assemblies (SADA) are usually installed in the pitch axis which rotate the solar arrays to track the Sun, can produce torques to compensate for the pitch-axis wheel failure. In addition, the attitude control of a flexible spacecraft poses a difficult problem. These difficulties include the strong nonlinear coupled dynamics between the rigid hub and flexible solar arrays, and the imprecisely known system parameters, such as inertia matrix, damping ratios, and flexible mode frequencies. In order to overcome these drawbacks, the adaptive Jacobian tracking fuzzy control is proposed for the combined attitude and sun-tracking control problem of a flexible spacecraft during attitude maneuvers in this work. For the adaptation of kinematic and dynamic uncertainties, the proposed scheme uses an adaptive sliding vector based on estimated attitude velocity via approximate Jacobian matrix. The unknown nonlinearities are approximated by deriving the fuzzy models with a set of linguistic If-Then rules using the idea of sector nonlinearity and local approximation in fuzzy partition spaces. The uncertain parameters of the estimated nonlinearities and the Jacobian matrix are being adjusted online by an adaptive law to realize feedback control. The attitude of the spacecraft can be directly controlled with the Jacobian feedback control when the attitude pointing trajectory is designed with respect to the spacecraft coordinate frame itself. A significant feature of this work is that the proposed adaptive Jacobian tracking scheme will result in not only the convergence of angular position and angular velocity tracking errors, but also the convergence of estimated angular velocity to

The 12C/13C Isotopic Ratio In Titan's Hydrocarbons

NASA Astrophysics Data System (ADS)

Nixon, Conor A.; Achterberg, R. K.; Vinatier, S.; Bezard, B.; Coustenis, A.; Teanby, N. A.; Irwin, P. G.; Cassini CIRS Team

2007-10-01

Isotopic ratios in planetary atmospheres are of considerable interest, yielding insights both about currently occurring processes, and also the formation and early evolution of the body. Before Cassini, ground-based measurements of Titan's 12C/13C in HCN showed no firm evidence of deviation from the terrestrial inorganic standard (88.9) - albeit with large error bars of 20% - contrasting the enrichment in nitrogen (15N/14N≈4.5 terrestrial). Since 2004, the Composite Infrared Spectrometer (CIRS) instrument on Cassini has recorded spectra of Titan's stratosphere globally, including the emissions of multiple isotopologues for certain hydrocarbons. We selected spectra for analysis from four flybys (T4, T12, T19, T22), covering five latitudes from 65°S to 71°N. By means of a radiative transfer code and inversion scheme, we have first modeled the ν4 band of 12CH4 at 1304 cm-1 to retrieve stratospheric temperatures, and subsequently the emissions of 13CH4, 12C2H2, 13C12CH2, 12C2H6 and 13C12CH6. Our results indicate 12C/13C = 81.2±2.0 for all three species combined over all five latitudes, in excellent agreement with the Huygens GCMS value of 12CH4/13CH4 = 82.3±1.0 (Niemann et al. 2005), some 9% lower than terrestrial inorganic, and lower than in ethane on Saturn (91 (-13) (+26)) and Jupiter (99 (-23) (+43)) (Sada et al. 1996). No latitude variation was detected, however the 12C/13C in the C2 species (83.9±3.1 in acetylene, 89.9±7.2 in ethane) were consistently higher than in methane (78.0±2.7) after considering random errors. Although it is possible that this is a real chemical or physical (condensation) effect, it is more likely due to systematic errors in our temperature profile, as our spectra do not yield independent temperature information at 10 mbar where the emissions of 13C12CH2 and 13C12CH6 originate, and we default to the Huygens probe temperatures. In future, this problem may be resolved by modeling CIRS limb spectra.

Titan's Carbon Isotopic Ratio: A Clue To Atmospheric Evolution?

NASA Astrophysics Data System (ADS)

Nixon, C. A.; Jennings, D. E.; Romani, P. N.; Jolly, A.; Teanby, N. A.; Irwin, P. G.; Bézard, B.; Vinatier, S.; Coustenis, A.; Flasar, F. M.

2009-12-01

In this presentation we describe the latest results to come from Cassini CIRS and ground-based telescopic measurements of Titan's 12C/13C ratio in atmospheric molecules, focusing on hydrocarbons. Previously, the Huygens GCMS instrument measured 12CH4/13CH4 to be 82±1 (Niemann et al., Nature, 438, 779-784, 2005), substantially and significantly lower than the VPDB inorganic Earth standard of 89.4. It is also at odds with measurements for the giant planets. Cassini CIRS infrared spectra have confirmed this enhancement in 13CH4, but also revealed that the ratio in ethane, the major photochemical product of methane photolysis, does not appear enhanced (90±7) (Nixon et al.. Icarus, 195, 778-791, 2008) and is compatible with the terrestrial and combined giant planet value (88±7, Sada et al., Ap. J., 472, p. 903-907, 1996). Recently-published results from spectroscopy using the McMath-Pierce telescope at Kitt Pitt (Jennings et al., JCP, 2009, in press) have confirmed this deviation between methane and ethane, and an explanation has been proposed. This invokes a kinetic isotope effect (KIE) in the abstraction of methane by ethynyl, a major ethane formation pathway, to preferentially partition 12C into ethane and leave an enhancement in atmospheric 13CH4 relative to the incoming flux from the reservoir. Modeling shows that a steady-state solution exists where the 12C/13C methane is decreased from the reservoir value by exactly the KIE factor (the ratio of 12CH4 to 13CH4 abstraction reaction rates): which is plausibly around 1.08, very close to the observed amount. However, a second solution exists in which we are observing Titan about ~1 methane lifetime after a major injection of methane into the atmosphere which is rapidly being eliminated. Updated measurements by Cassini CIRS of both the methane and ethane 12C/13C ratios will be presented, along with progress in interpreting this ratio. In addition, we summarize the 12C/13C measurements by CIRS in multiple other Titan

Titan's methane clock

NASA Astrophysics Data System (ADS)

Nixon, C. A.; Jennings, D. E.; Romani, P. N.; Teanby, N. A.; Irwin, P. G. J.; Flasar, F. M.

2010-04-01

Measurements of the 12C/13C and D/H isotopic ratios in Titan's methane show intriguing differences from the values recorded in the giant planets. This implies that either (1) the atmosphere was differently endowed with material at the time of formation, or (2) evolutionary processes are at work in the moon's atmosphere - or some combination of the two. The Huygens Gas Chromatograph Mass Spectrometer Instrument (GCMS) found 12CH4/13CH4 = 82 +/- 1 (Niemann et al. 2005), some 7% lower than the giant planets' value of 88 +/- 7 (Sada et al. 1996), which closely matches the terrestrial inorganic standard of 89. The Cassini Composite Infrared Spectrometer (CIRS) has previously reported 12CH4/13CH4 of 77 +/-3 based on nadir sounding, which we now revise upwards to 80 +/- 4 based on more accurate limb sounding. The CIRS and GCMS results are therefore in agreement about an overall enrichment in 13CH4 of ~10%. The value of D/H in Titan's CH4 has long been controversial: historical measurements have ranged from about 8-15 x 10-5 (e.g. Coustenis et al. 1989, Coustenis et al. 2003). A recent measurement based on CIRS limb data by Bezard et al. (2007) puts the D/H in CH4 at (13 +/- 1) x 10-5, very much greater than in Jupiter and Saturn, ~2 x 10-5 (Mahaffy et al. 1998, Fletcher et al. 2009). To add complexity, the 12C/13C and D/H vary among molecules in Titan atmosphere, typically showing enhancement in D but depletion in 13C in the daughter species (H2, C2H2, C2H6), relative to the photochemical progenitor, methane. Jennings et al. (2009) have sought to interpret the variance in carbon isotopes as a Kinetic Isotope Effect (KIE), whilst an explanation for the D/H in all molecules remains elusive (Cordier et al. 2008). In this presentation we argue that evolution of isotopic ratios in Titan's methane over time forms a ticking 'clock', somewhat analogous to isotopic ratios in geochronology. Under plausible assumptions about the initial values and subsequent replenishment, various

Water on the Early M Supergiant Stars α Orionis and μ Cephei

NASA Astrophysics Data System (ADS)

Tsuji, T.

2000-08-01

We reanalyze the spectra of α Ori (M2 Iab) and μ Cep (M2 Ia) observed with the balloon-borne telescope Stratoscope II more than 35 years ago, and we confirm the presence of water in these early M supergiant stars. This identification was first proposed by the Stratoscope observers themselves (Woolf, Schwarzschild, and Rose in 1964; and Danielson, Woolf, and Gaustad in 1965), but this important discovery was overlooked for a long time without any follow-up observation. Consequently, this finding has so far had little influence on the theory of the atmosphere of red supergiant stars. A reason for this may be due to an early criticism by Wing and Spinrad, who suggested CN instead of H2O for the spectral features observed by Stratoscope II. This alternative proposition has more easily been accepted since CN has widely been observed from the Sun to red supergiants, while H2O has been observed only in very cool stars such as Mira variables. In fact, we confirm that the self-consistent photospheric model of the early M supergiants shows CN bands but no H2O band in the near-infrared. Nevertheless, we find that the contribution of CN is only minor and that H2O should be the dominant absorber for the 1.4 and 1.9 μm features on the Stratoscope spectra of α Ori and μ Cep, a conclusion opposite to that of Wing and Spinrad. The observed spectra can best be interpreted by the water gas with the column density of the order of 1020 cm-2 and temperature about 1500+/-500 K, but they cannot be originating in the photosphere. We suggest a possible presence of a gaseous component not as hot as the chromosphere but warmer than the cool expanding envelope. On the other hand, we notice that the mid-infrared pure-rotation lines of H2O recently discovered on Betelgeuse (α Ori) and Antares (α Sco) by Jennings and Sada may partly be originating in the photosphere, even though the larger part should again be nonphotospheric in origin. Thus, the presence of water possibly originating in

The 12C/ 13C isotopic ratio in Titan hydrocarbons from Cassini/CIRS infrared spectra

NASA Astrophysics Data System (ADS)

Nixon, C. A.; Achterberg, R. K.; Vinatier, S.; Bézard, B.; Coustenis, A.; Irwin, P. G. J.; Teanby, N. A.; de Kok, R.; Romani, P. N.; Jennings, D. E.; Bjoraker, G. L.; Flasar, F. M.

2008-06-01

We have analyzed infrared spectra of Titan recorded by the Cassini Composite Infrared Spectrometer (CIRS) to measure the isotopic ratio 12C/ 13C in each of three chemical species in Titan's stratosphere: CH 4, C 2H 2 and C 2H 6. This is the first measurement of 12C/ 13C in any C 2 molecule on Titan, and the first measurement of 12CH 4/ 13CH 4 (non-deuterated) on Titan by remote sensing. Our spectra cover five widely-spaced latitudes, 65° S to 71° N and we have searched for both latitude variability of 12C/ 13C within a given species, and also for differences between the 12C/ 13C in the three gases. For CH 4 alone, we find C12/C13=76.6±2.7 (1- σ), essentially in agreement with the 12CH 4/ 13CH 4 measured by the Huygens Gas Chromatograph/Mass Spectrometer instrument (GCMS) [Niemann, H.B., and 17 colleagues, 2005. Nature 438, 779-784]: 82.3±1.0, and also with measured values in H 13CN and 13CH 3D by CIRS at lower precision [Bézard, B., Nixon, C., Kleiner, I., Jennings, D., 2007. Icarus 191, 397-400; Vinatier, S., Bézard, B., Nixon, C., 2007. Icarus 191, 712-721]. For the C 2 species, we find C12/C13=84.8±3.2 in C 2H 2 and 89.8±7.3 in C 2H 6, a possible trend of increasingly value with molecular mass, although these values are both compatible with the Huygens GCMS value to within error bars. There are no convincing trends in latitude. Combining all fifteen measurements, we obtain a value of C12/C13=80.8±2.0, also compatible with GCMS. Therefore, the evidence is mounting that 12C/ 13C is some 8% lower on Titan than on the Earth (88.9, inorganic standard), and lower than typical for the outer planets ( 88±7 [Sada, P.V., McCabe, G.H., Bjoraker, G.L., Jennings, D.E., Reuter, D.C., 1996. Astrophys. J. 472, 903-907]). There is no current model for this enrichment, and we discuss several mechanisms that may be at work.