Reassessment of probabilistic seismic hazard in the Marmara region

USGS Publications Warehouse

Kalkan, Erol; Gulkan, Polat; Yilmaz, Nazan; Çelebi, Mehmet

2009-01-01

In 1999, the eastern coastline of the Marmara region (Turkey) witnessed increased seismic activity on the North Anatolian fault (NAF) system with two damaging earthquakes (M 7.4 Kocaeli and M 7.2 D??zce) that occurred almost three months apart. These events have reduced stress on the western segment of the NAF where it continues under the Marmara Sea. The undersea fault segments have been recently explored using bathymetric and reflection surveys. These recent findings helped scientists to understand the seismotectonic environment of the Marmara basin, which has remained a perplexing tectonic domain. On the basis of collected new data, seismic hazard of the Marmara region is reassessed using a probabilistic approach. Two different earthquake source models: (1) the smoothed-gridded seismicity model and (2) fault model and alternate magnitude-frequency relations, Gutenberg-Richter and characteristic, were used with local and imported ground-motion-prediction equations. Regional exposure is computed and quantified on a set of hazard maps that provide peak horizontal ground acceleration (PGA) and spectral acceleration at 0.2 and 1.0 sec on uniform firm-rock site condition (760 m=sec average shear wave velocity in the upper 30 m). These acceleration levels were computed for ground motions having 2% and 10% probabilities of exceedance in 50 yr, corresponding to return periods of about 2475 and 475 yr, respectively. The maximum PGA computed (at rock site) is 1.5g along the fault segments of the NAF zone extending into the Marmara Sea. The new maps generally show 10% to 15% increase for PGA, 0.2 and 1.0 sec spectral acceleration values across much of Marmara compared to previous regional hazard maps. Hazard curves and smooth design spectra for three site conditions: rock, soil, and soft-soil are provided for the Istanbul metropolitan area as possible tools in future risk estimates.

Paleo-earthquake timing on the North Anatolian Fault: Where, when, and how sure are we?

NASA Astrophysics Data System (ADS)

Fraser, J.; Vanneste, K.; Hubert-Ferrari, A.

2009-04-01

The North Anatolian Fault (NAF) traces from the Karilova Triple Junction in the east 1400km into the Aegean Sea in the west, forming a northwardly convex arch across northern Turkey. In the 20th century the NAF ruptured in an approximate east to west migrating sequence of large, destructive and deadly earthquakes. This migrating sequence suggests a simple relationship between crustal loading and fault rupture. A primary question remains unclear: Does the NAF always rupture in episodic bursts? To address this question we have reanalysed selected pre-existing paleoseismic investigations (PIs), from along the NAF, using Bayesian statistical modelling to determine a standardised record of the temporal probability distribution of earthquakes. A wealth of paleoseismic records have accumulated over recent years concerning the NAF although sadly much research remains un-published. A significant output of this study is tabulated results from all of the existing published paleoseismic studies on the NAF with recalibration of the radiocarbon ages using standardized methodology and standardized error reporting by determining the earthquake probability rather than using errors associated with individual bounding dates. We followed the approach outlined in Biasi & Weldon (1994) and in Biasi et al. (2002) to calculate the actual probability density distributions for the timing of paleoseismic events and for the recurrence intervals. Our implementation of these algorithms is reasonably fast and yields PDFs that are comparable to but smoother than those obtained by Markov Chain Monte Carlo type simulations (e.g., OxCal, Bronk-Ramsey, 2007). Additionally we introduce three new earthquake records from PIs we have conducted in spatial gaps in the existing data. By presenting all of this earthquake data we hope to focus further studies and help to define the distribution of earthquake risk. Because of the long historical record of earthquakes in Turkey, we can begin to address some fundamental questions in the field of paleoseismology. For example; can we use sample ages from PIs situated 100s of kilometres apart, on a historical rupture segment, to more accurately determine the timing of paleo-earthquakes? Because the approach to earthquake age constraint is continuing to evolve, this study highlights the importance of publishing raw data from paleoseismic investigations. Biasi, G. and R. Weldon (1994). "Quantitative refinement of calibrated C-14 distributions."Quaternary Research 41: 1-18 Biasi, G. and R. Weldon (2002). "Paleoseismic Event Dating and the Conditional Probability of Large Earthquakes on the Southern San Andreas Fault, California." Bulletin of the Seismological Society of America 92(7): 2761-2781. Bronk Ramsey, C. (2007). OxCal version 4.0.5 Radiocarbon Calibration software.

Delineation of major geologic structures in Turkey using SIR-B data

NASA Technical Reports Server (NTRS)

Toksoz, M. N.; Pettengill, G. H.; Ford, P.; Gulen, L.

1984-01-01

Shuttle Imaging Radar-B (SIR-B) images of well mapped segments of major faults, such as the North Anatolian Fault (NAF) and East Anatolian Fault (EAF) will be studied to identify the prominent signatures that characterize the fault zones for those specific regions. The information will be used to delineate the unmapped fault zones in areas with similar geological and geomorphological properties. The data obtained from SIR-B images will be compared and correlated with the LANDSAT thematic mapper and seismicity alignments based on well constrained earthquake epicenters.

Intra-basinal water movements induced by faulting: The August 17, 1999, Golcuk (Izmit Bay) earthquake (M(W) = 7.4)

USGS Publications Warehouse

Ozturk, H.; Koral, H.; Geist, E.L.

2000-01-01

A strong earthquake (M(w) = 7.4) occurred near the town of Golcuk, Izmit Bay, Western Turkey, at 00:01 GMT on August 17, 1999. Izmit Bay is a E-W trending pull-apart basin with a surface area of about 300 km2 along the North Anatolian Fault Zone (NAF), in the eastern extension of the Sea of Marmara. The earthquake was caused by a westerly movement of the Anatolian plate along NAF and was accompanied by isolated, chaotic water movements along the northern and southern shores of the bay. At localities along the shoreline a sudden drop in sea level, and a subsequent rise was prominent. The mode of observed sea-level movements rules out the occurrence of a basin-wide tsunami, sensu stricto. Instead, the water movements are attributed to localized sudden dip-slip movements of fault blocks in this pull-apart basin. (C) 2000 Elsevier Science B.V.

The 2014, MW6.9 North Aegean earthquake: seismic and geodetic evidence for coseismic slip on persistent asperities

NASA Astrophysics Data System (ADS)

Konca, Ali Ozgun; Cetin, Seda; Karabulut, Hayrullah; Reilinger, Robert; Dogan, Ugur; Ergintav, Semih; Cakir, Ziyadin; Tari, Ergin

2018-05-01

We report that asperities with the highest coseismic slip in the 2014 MW6.9 North Aegean earthquake persisted through the interseismic, coseismic and immediate post-seismic periods. We use GPS and seismic data to obtain the source model of the 2014 earthquake, which is located on the western extension of the North Anatolian Fault (NAF). The earthquake ruptured a bilateral, 90 km strike-slip fault with three slip patches: one asperity located west of the hypocentre and two to the east with a rupture duration of 40 s. Relocated pre-earthquake seismicity and aftershocks show that zones with significant coseismic slip were relatively quiet during both the 7 yr of interseismic and the 3-month aftershock periods, while the surrounding regions generated significant seismicity during both the interseismic and post-seismic periods. We interpret the unusually long fault length and source duration, and distribution of pre- and post-main-shock seismicity as evidence for a rupture of asperities that persisted through strain accumulation and coseismic strain release in a partially coupled fault zone. We further suggest that the association of seismicity with fault creep may characterize the adjacent Izmit, Marmara Sea and Saros segments of the NAF. Similar behaviour has been reported for sections of the San Andreas Fault, and some large subduction zones, suggesting that the association of seismicity with creeping fault segments and rapid relocking of asperities may characterize many large earthquake faults.

Estimating slip deficit of the North Anatolian Fault beneath the Sea of Marmara, Turkey, using on- and off-shore geodetic data

NASA Astrophysics Data System (ADS)

Yamamoto, R.; Kido, M.; Ohta, Y.; Takahashi, N.; Yamamoto, Y.; Kalafat, D.; Pinar, A.; Ozener, H.; Ozeren, M. S.; Yoshiyuki, K.

2016-12-01

The North Anatolian Fault (NAF) in the northern Turkey regionally has right-lateral strike-slip motion. In the last decade, seismic activities have been migrating from east to west along the fault. In 1999, Izmit and Duzce Earthquakes were respectively occurred at 100 km and 200 km east of Istanbul, while it remains un-ruptured in the vicinity of Istanbul beneath the Sea of Marmara. In this region, onshore geodetic tools cannot be used and we instead used "seafloor acoustic extensometers" to detect slip deficit rate across the western part of the NAF (around 27.7 °E). A pair of extensometers can periodically measure precise range (about 3-4 mm precision per 1 km baseline) by observing round-trip time of acoustic signal between the two. We installed four instruments in September 2014 and an additional one in March 2015 across the NAF. We have recovered data for about 600-days through acoustic modem. By correcting travel-times for sound velocity using concurrently measured temperature, pressure and tilt change of instruments, we obtained 8-10 ±1 mm/yr of right-lateral movement at the site. Combing the result with on-shore GNSS data across the Sea of Marmara, we constructed a possible fault model. According to the model in Kaneko et al. (2013), we simply assume a bimodal slip condition on the fault plane that infinitely continues to the E-W direction; full-creep (25 mm/yr as is given at infinite distant from the fault plane) deeper than 15 km and applied an overriding partially locked layer (17 mm/yr slip deficit as is obtained by extensometers). We calculated 2-D displacement field in a homogeneous elastic half-space medium. With this model, N-S variation of on-shore GNSS data across the Sea of Marmara can be reasonably explained. However, due to the lack of GNSS site near the fault plane, constraint on the depth of the partially locked layer is not sufficient. We have newly installed GNSS sites, one of which is closer to the fault plane ( 10 km) than before and will be expected to provide much information on the fault condition. Acknowledgement: This observation is carried out in the MarDiM (Marmara Disaster Mitigation) project, SATREPS promoted by JICA/JST and Ministry of Development of Turkey.

Installation of EarthScope Borehole Strainmeters in Turkey to complement GONAF.

NASA Astrophysics Data System (ADS)

Johnson, W.; Gottlieb, M. H.; Mencin, D.; Van Boskirk, E.; Ozener, H.; Bohnhoff, M.; Bulut, F.; Bal, O.; Acarel, D.; Aydin, H.; Mattioli, G. S.

2015-12-01

Twice in the past 1000 years a sequence of damaging earthquakes has propagated over a period of a few decades along the North Anatolian Fault (NAF) in Turkey towards Istanbul, with the final earthquake in the sequence catastrophically damaging the city. This occurred most recently in 1509, causing 10,000 casualties in a population of about 200,000. The population is now 20 million, the building stock more fragile, and the last earthquake of the current sequence is considered imminent. Since July 2014, UNAVCO has installed 2 EarthScope borehole geophysical instrument strings, which include Gladwin Tensor strainmeters and passive, short-period 3-component seismometers, into boreholes provided by internationally supported Geophysical Observatory at the North Anatolian Fault (GONAF) and Bogazici University Kandilli Observatory. Funding for instruments and staff participation was provided by NSF. If the project remains on schedule, we anticipate that 4 additional BSM strings will be installed by the fall 2015. Our joint international project gives an opportunity to enhance the detection capability of a suite of deep seismometers (GONAF) installed near Istanbul and will permit us to image dynamic rupture along the NAF and to monitor and better understand the tectonic processes leading to failure. The tectonic and geodynamic environment of the NAF near Istanbul in many ways resembles the San Andreas Fault setting of San Francisco; these instruments will enhance the ability to monitor ultra-slow process near the probable source zone of the Mw>7 earthquake beneath the Marmara Sea on the NAF This project has provided UNAVCO an opportunity to gain experience in strainmeters installations outside of North America. The techniques developed to adapt to the challenges of installing borehole strainmeters on islands and other remote locations with limited resources will greatly enhance our ability to install these BSM instruments in similar locations in the future.

Gas, slumps and faulting in the Marmara Sea: new results from TAMAM high-resolution seismic reflection data

NASA Astrophysics Data System (ADS)

Shillington, D. J.; Dondurur, D.; Seeber, L.; Steckler, M. S.; Sorlien, C. C.; Diebold, J. B.; Cifci, G.; Gurcay, S.; Okay, S.; Imren, C.; Kurt, H.; Timur, D.; Demirbag, E.

2009-12-01

The Marmara Sea comprises a series of active transtensional basins forming along the North Anatolian Fault (NAF). Both deformation and sedimentation are punctuated by large, destructive earthquakes. Slumping and gas migration also appear to be coupled with these seismotectonic processes. Sediment cores, water column measurements, ROV observations and Chirp data acquired in the Marmara Sea over the last 10 years indicate numerous fluid/gas seeps along active faults, particularly the NAF. Furthermore, some authors infer fluidization and collapse of gas-charged sediments occurred during the 1999 Gulf of Izmit earthquake (farther east along the NAF) based on the presence of mudvolcanoes and slumps after the earthquake. These studies hint at interesting interactions between tectonics, slumping and fluid/gas migration. However, they comprise detailed observations focused on the fault and the upper 20 m of sediments and thus do not provide a complete picture. Here we use a new high-resolution multi-channel seismic (MCS) reflection dataset acquired in the Marmara Sea in July 2008 to elucidate the spatial relationships between gas, slumps and tectonic elements, particularly faults and progressively tilted sediments. The Turkish-American MAmara Multichannel (TAMAM) project involved the acquisition of >2600 km of MCS data throughout the Marmara Sea aboard the R/V K. Piri Reis using a GI gun and a ~450-m-long streamer. We employ several techniques to extract information on the distribution of gas from these data: 1) visual identification of attributes associated with gas (wipe-out zones, high amplitudes, polarity reversals, etc) using a seismic interpretation package, 2) instantaneous attribute analysis (particularly frequency and amplitude), and 3) AVO on select data in shallow water. Many TAMAM profiles exhibit abundant seismic signatures associated with gas. Likewise, many structures are apparent in TAMAM data that may be related to gravitational collapse, and they cover a wide range of sizes, forms, and ages. Possible slumps are observed in our data in the southern portions of the Tekirdag and Cinarcik basins, on both flanks of the Central High, and north of Kumburgaz Basin. Some are clearly non-tectonic, but others may be, and their significance is controversial. Preliminary results from our work suggest that shallow subsurface gas is particularly prevalent in sediments on the Central and Western Highs and in the North Imrali Basin. It occurs in gravitational structures as amplitude anomalies at the apices of waves or blocks. Furthermore, our initial results show abundant gas north of the Imrali Fault and along thrusts associated with the Central and Western highs. Gas is also observed near the NAF. However, gas also occurs away from faults and possible slumps. Our new constraints on the spatial distribution of gas, slumps and shallow faulting from MCS and Chirp data will be used to test competing models for the relationship between these features.

Undersea acoustic telemetry across the North Anatolian Fault, Marmara Sea: results from the first 6 months of monitoring of the fault displacement

NASA Astrophysics Data System (ADS)

Royer, J. Y.; Deschamps, A.; Piete, H.; Sakic, P.; Ballu, V.; Apprioual, R.; Kopp, H.; Lange, D.; Ruffine, L.; Géli, L.

2015-12-01

Located in the Marmara Sea, the Istanbul-Silivri segment of the North Anatolian Fault (NAF) is known to be a seismic gap since 1766, although, in the last century, the NAF has caused major devastating earthquakes over most of its extent. This fault segment, void of seismicity, may be either creeping aseismically or blocked and accumulating enough strain to produce an earthquake of magnitude 7 or greater. This section of the NAF may thus represent a major seismic and tsunamigenic hazard for the Istanbul megalopolis, located only 40 km away. The objective of the MARSITE project, funded by the European Union and coordinated by the Observatory of the University of Kandilli (KOERI), is to determine the blocking state of the Istanbul-Silivri fault segment. In this context, an array of 10 acoustic transponders has been deployed on either sides of the fault, in the eastern part of the Kumburgaz Basin, to measure the displacements of the fault over a period of 3 to 5 years. The telemetric beacons (4 from the University of Brest and 6 from the GEOMAR Institute in Kiel) form two arrays fitted in one another. The principle of the experiment is to repeatedly measure the distance (ie two-way-travel time of acoustic pings) between pairs of beacons and thus to monitor the deformation of an array of 9 baselines, 500m to 3000m long, of which 5 cross obliquely the assumed fault trace. The French and German arrays are independent but ensure a redundancy of rangings along common baselines. Each acoustic transponder also monitors the temperature, pressure, sound-velocity and attitude (tiltmeters), every one or two hours. Data are stored in each beacon and can be downloaded from the surface using an acoustic modem. We present here the first 6 months of recording by the French array, from November 1st, 2014 to April 25, 2015. All acoustic transponders worked nominally for 6 months and appear to have remained stable on the seafloor. Recorded sea-bottom temperatures provide evidence for transient changes likely due to episodic flows of deep colder water across the Kumburgaz Basin. Pressure records display diurnal variations related to the tides. Both parameters affect the sound-velocity and thus the acoustic ranges, and are used to correct the baselines.

Mud volcano monitoring and seismic events along the North Anatolian Fault (Sea of Marmara)

NASA Astrophysics Data System (ADS)

Javad Fallahi, Mohammad; Lupi, Matteo; Mazzini, Adriano; Polonia, Alina; D'Alessandro, Antonino; D'Anna, Giuseppe; Gasperini, Luca

2017-04-01

The Sea of Marmara, a pull-apart basin formed along the northern strand of the North Anatolian Fault (NAF) system, is considered a seismic gap, that will be filled in the next decades by a large magnitude (M>7) earthquake, close to the Istanbul Metropolitan area (12 million inhabitants). For this reason, several marine geological and geophysical studies have been carried out in this region, starting from the destructive 1999 Mw 7.4 Izmit earthquake, to gather information relative to seismogenic potential of major fault strands. Together with these studies, in the frame of EC projects (i.e., MarmESONET and Marsite, among others), an intensive program of long-term monitoring of seismogenic faults was carried out using seafloor observatories deployed during several expeditions led by Italian, French and Turkish groups. These expeditions included MARM2013, on board of the R/V Urania, of the Italian CNR, when four ocean bottom seismometers (OBS) were deployed in the central part of the Sea of Marmara, at depths between 550 and 1000 m. One of the main aims of the experiment was to assess the long-term seismic activity along an active segment of the NAF, which connects the central and the western basins (depocenters), where the principal deformation zone appears relatively narrow and almost purely strike-slip. The present study shows the results of processing and analysis of continuous data records from these OBS stations during 50 days. We were able to detect seismic signal produced by an active mud volcano located close to the NAF trace, from about 3 to 6 km of distance from the OBS stations. Additionally, we captured the May 24, 2014, Mw 6.9 strike-slip earthquake occurred in the northern Aegean Sea between Greece and Turkey, which caused serious damage on the Turkish island of Imbros and the cities of Edirne and Çanakkale, as well as on the Greek island of Lemnos. The earthquake nucleated on the westward continuation of the NAF system in the NE Aegean Sea, and was felt in Bulgaria and southern Romania. Several aftershocks followed the main shock, the strongest measuring 5.3 of magnitude. To verify the effects of this external forcing on the activity of the submarine mud volcano in Marmara, we calculated the root-mean-square (RMS) and standard deviation (STD) on three-minute waveform segments in a period from 2014.04.11 to 2014.05.31 in the 10-25 Hz frequency band. In addition, we also calculated auto- and cross-correlation of seismic ambient noise in the same time-period and frequency range to assess the variations of waveform coherency prior to the earthquake. Preliminary results show periodic changes of RMS and STD amplitudes, which may result from the effects of tides, but no short- or long-term precursory signs of the earthquake detected by our approach.

Offshore Seismic Observation in the Western Marmara Sea, Turkey

NASA Astrophysics Data System (ADS)

Yamamoto, Y.; Takahashi, N.; Citak, S.; Kalafat, D.; Pinar, A.; Gurbuz, C.; Kaneda, Y.

2014-12-01

The North Anatolian Fault (NAF) extends 1600 km westward from a junction with the East Anatolian Fault at the Karliova Triple Junction in eastern Turkey, across northern Turkey and into the Aegean Sea, accommodating about 25 mm/yr of right-lateral motion between Anatolia and the Eurasian plate. Since 1939, devastating earthquakes with magnitude greater than seven ruptured NAF westward, starting from 1939 Erzincan at the eastern Turkey and including the latest 1999 Izmit-Golcuk and the Duzce earthquakes in the Marmara region. Considering the fault segments ruptured by the May 24th, 2014 Northern Aegean earthquake, the only un-ruptured segments left behind NAF locate beneath the Marmara Sea and those segments keep their mystery due to their underwater location. To clarify the detailed fault geometry beneath the western Marmara Sea, we started to operate a series of ocean bottom seismographic (OBS) observations. As a first step, we deployed 3 pop-up type OBSs on 20th of March 2014 as a trial observation, and recovered them on 18thof June 2014. Although one of the OBSs worked only 6 days from the start of the observation, other two OBSs functioned properly during the whole 3-month observation period. Only 8 earthquakes were reported near the OBS network in 3 months periods according to the Kandilli Observatory and Earthquake Research Institute catalogue. Thus, we first searched for the microearthquakes missing by the land seismic network and estimated their precious location by using the initial 6 days data. We could identify about 50 earthquakes with more than 5 picking data of P and S first arrivals, and half of them located near the NAF. We also tested the hypocenter relocation by combining the land and OBS seismic data for the 8 earthquakes, and found that these earthquakes are located in between 12-24 km depths. Next, we are planning to deploy 10 OBSs from September 2014 to June 2015 as a second step for our observation. At the AGU fall meeting, we will be able to introduce the OBS location of this new observation. These OBS observations are conducted as a part of the "Earthquake and Tsunami Disaster Mitigation in the Marmara Region and Disaster Education in Turkey" project, financially supported by Japan International Cooperation Agency (JICA), Japan Science and Technology Agency (JST), and the Ministry of Development in Turkey.

2D - 3D high resolution seismic survey on the Sea of Marmara - Western High

NASA Astrophysics Data System (ADS)

Saritas, H.; Cifci, G.; Géli, L.; Thomas, Y.; Marsset, B.; Rochat, A.; Westbrook, G. K.; Ker, S.; Atgin, O.; Akhun ćoşkun, S. D.; Grall, C.; Henr, P.; Gürçay, S.; Okay, S.; ćoşkun, S.; Özkan, Ö.; Barın, B.

2012-04-01

In the Sea of Marmara the main strand of the NAF is made up of the Ganos (15km long), Central Marmara (150 km), and North Boundary (45 km) fault segment (Okay et al., 2000). The Central Marmara Fault crosses over The Western High which is located between Tekirdag and Central Marmara Basins. The Western High and Cinarcik Basin is one of the major regions of geological interest which is the area close to the NAF where evidence of gas hydrates and gas escapes have been observed during previous scientific cruises. To understand movement of the NAF and origin of the gas , collecting data was focused on these areas by the latter cruises. It started with TAMAM (Turkish-American Marmara Multichannel) cruise in July 2008 by R/V Koca Piri Reis which belongs to Dokuz Eylul University , and after that it continued with MARMESONET (Marmara Demonstration Mission Program supported by European Seafloor Observatory Network) in December 2009 by R/V Le Suroit which belongs to IFREMER. This cruise consisted of two leg; leg-1 was about collecting multibeam and AUV data, Leg-2 was about collecting High Resolution 3D Seismic data. The last cruise PirMarmara was carried out in June 2010 by R/V Koca Piri Reis , its aim was that collecting 2D High Resolution Seismic Data .These projects are grouped in ESONET MARMARA-DM Project. 3D seismic data provide detailed information about fault distribution and subsurface structures. Computer-based interpretation and display of 3D seismic data allow for more thorough analysis than 2D seismic data. The objectives of this survey are; find gas strata and gas hydrate formation location in the western high, geological description of this area, understand tectonical movement related to dextral strike slip North Anatolian fault, focus on the mud volcano in which close to NAF, find gas hydrate and origin of the existing gas , and location of the gas escaping, investigate the creation of the Marmara Sea concerning with Western High. Integrate good velocity information which is obtained from 2D seismic processing with to 3D seismic data for effective interpretation. In conclusion, there were some cruises related to collecting kind of the marine geology and geophysics data in The Western High. The investigations have been focused on gas hydrate, gas escape, location of the gas strata and tectonic movement. The Data has been processed and started to interpretation. Keywords: Sea of Marmara, Western High, Gas field, Gas Hyrate, 2D-3D Seismic

Preliminary results about the Quaternary activiy of the Ovacik Fault, Eastern Turkey

NASA Astrophysics Data System (ADS)

Zabcı, Cengiz; Sançar, Taylan; Aktaǧ, Alican

2013-04-01

The Erzincan Basin and the surrounding region have a complex structure, which is formed by the interaction of the North Anatolian Fault (NAF), the Northeast Anatolian Fault (NEAF), the Pülümür Fault (PF), and the Ovacık Fault (OF). The region has been shaked many times by devastating earthquakes throughout both the instrumental and the historical periods. The infamous 26 December 1939 Erzincan Earthquake (M~7.9) is the largest event, which was instrumentally recorded along the NAF. Moreover, the eastern continuation of the surface rupture of this earthquake, "the Yedisu Segment", is known as one of the two seismic gaps on this dextral shear zone. We started multi-disciplinary studies on the OF, which has relatively very limited data. Even though some researches think about this tectonic feature as a non-active fault, recent GPS measurements point strain accumulation along it. In addition to that 1992 Erzincan and 2003 Pülümür earthquakes loaded additional stress on the neighboring faults, including the OF. The OF elongate between the SE Erzincan Basin and Kemaliye (Erzincan) about 110 km with a general strike of N60E. The clear morphological expression of the fault is especially observed around Ovacık, Tunceli. The OF delimits the Jurassic aged Munzur limestone in the north and the Miocene volcanoclastics and Permo-Carboniferous schist in the south in this vicinity. We identified many offset features, such as wash plains, moraines, alluvial fans and inset terraces in our preliminary morphological maps. The measured displacements change from 20 to 350 m, which may play a critical role in the calculation of the geological slip-rate. Moreover, we used morphological indices, such as topographic profiling, hypsometric integral, basin asymmetry, and the mountain front sinuosity to quantify the activity of the OF. Our preliminary results clearly point out the necessity of future studies, which may help to understand the earthquake potential of this poorly known tectonic feature.

Paleoseismic history and slip rate along the Sapanca-Akyazı segment of the 1999 İzmit earthquake rupture (Mw = 7.4) of the North Anatolian Fault (Turkey)

NASA Astrophysics Data System (ADS)

Dikbaş, Aynur; Akyüz, H. Serdar; Meghraoui, Mustapha; Ferry, Matthieu; Altunel, Erhan; Zabcı, Cengiz; Langridge, Robert; Yalçıner, Cahit Çağlar

2018-07-01

The Sapanca-Akyazı segment (SAS) is located on western part of the North Anatolian Fault (NAF) of Turkey. It was ruptured together with four other segments during the 17th August 1999 İzmit earthquake (Mw = 7.4) which caused 145-km-long surface rupture in the east Marmara region. We conducted geomorphological investigations and 2D-3D paleoseismic trenching at 3 different sites near the Sakarya River along the SAS to obtain new data for the timing of past earthquakes and slip rate of this section of the NAF. Detailed investigations using Ground Penetrating Radar on the western bank of the Sakarya River reveal 18.5 ± 0.5 m of right-lateral cumulative offset of an alluvial terrace dated as 850 ± 11 years BP using Optically Stimulated Luminescence. The analysis of trench data from the three different sites of the SAS indicates the occurrence of four surface rupturing past earthquakes including the 1999 İzmit earthquake. According to the radiocarbon dating, these paleo-earthquakes can be correlated with the 1719 CE, 1567 CE, and 1037 CE historical earthquakes and suggest an average recurrence period between 273 and 322 years. The total dextral offset, the age of trench units and the terrace deposits together suggest a 22 ± 3 mm/yr slip rate for this portion of the NAF.

Fault creep and persistent asperities on the western section of the North Anatolian Fault, Turkey

NASA Astrophysics Data System (ADS)

Floyd, M.; Reilinger, R. E.; Ergintav, S.; Karabulut, H.; Vernant, P.; Konca, A. O.; Dogan, U.; Cetin, S.; Cakir, Z.; Mencin, D.; Bilham, R. G.; King, R. W.

2017-12-01

We interpret new geodetic and seismic observations along the western section of the North Anatolian Fault (NAF) in Turkey as evidence for persistent asperities on the fault surface. Analysis of geodetic and seismic observations of seven segments of the fault at different stages of the earthquake cycle suggest that areas of the fault surface that are accumulating strain (i.e. asperities) are deficient in interseismic seismicity and earthquake aftershocks compared to areas between asperities that are failing at least in part by fault creep. From west to east, these segments include the 2014 M6.9 Gokceada earthquake and 1912 M7.4 Ganos earthquake segments, the Sea of Marmara and Princes' Islands seismic "gaps", the 1999 M7.6/7.2 Izmit/Duzce earthquake segments, and the 1944 M7.4 Ismetpasa segment, which remains actively creeping. Aspects of each segment contribute to our interpretation of overall fault behavior. The most well-defined distribution of coseismic slip in relation to pre- and post-earthquake seismicity is for the 2014 Gokceada event. The most complete set of geodetic observations (pre-, co-, and short- and long-term post-seismic) come from the 1999 Izmit and Duzce events. Simple three-layer elastic models including a middle layer that is fully locked between earthquakes, and shallow and deeper layers that are allowed to creep, can account for these observations of the deformation cycle. Recent observations from InSAR, creepmeters and small-aperture GPS profiles indicate ongoing surface and shallow fault creep rates, as allowed by the upper layer of the three-layer model. Conceptually, creep in the deeper layer represents the deep healing of the fault following the earthquake. For the Izmit and Duzce earthquake segments, healing from prior earthquakes was complete before the 1999 sequence. More generally, the consistent pattern of strain accumulation along the full length of the NAF, including the long eastern segments that ruptured in major earthquakes in 1939, 1942 and 1943, suggests that deep fault healing is complete over time scales much shorter than the earthquake repeat time. Given their similarities, these results may be applicable and provide insights into the mechanics of strain accumulation and earthquake potential along other continental strike-slip faults such as the San Andreas Fault.

Fluids along the North Anatolian Fault, Niksar basin, north central Turkey: Insight from stable isotopic and geochemical analysis of calcite veins

NASA Astrophysics Data System (ADS)

Sturrock, Colin P.; Catlos, Elizabeth J.; Miller, Nathan R.; Akgun, Aykut; Fall, András; Gabitov, Rinat I.; Yilmaz, Ismail Omer; Larson, Toti; Black, Karen N.

2017-08-01

Six limestone assemblages along the North Anatolian Fault (NAF) Niksar pull-apart basin in northern Turkey were analyzed for δ18OPDB and δ13CPDB using bulk isotope ratio mass spectrometry (IRMS). Matrix-vein differences in δ18OPDB (-2.1 to 6.3‰) and δ13CPDB (-0.9 to 4.6‰) suggest a closed fluid system and rock buffering. Veins in one travertine and two limestone assemblages were further subjected to cathodoluminescence, trace element (Laser Ablation Inductively Coupled Plasma Mass Spectrometry) and δ18OPDB (Secondary Ion Mass Spectrometry, SIMS) analyses. Fluid inclusions in one limestone sample yield Th of 83.8 ± 7.3 °C (±1σ, mean average). SIMS δ18OPDB values across veins show fine-scale variations interpreted as evolving thermal conditions during growth and limited rock buffering seen at a higher-resolution than IRMS. Rare earth element data suggest calcite veins precipitated from seawater, whereas the travertine has a hydrothermal source. The δ18OSMOW-fluid for the mineralizing fluid that reproduces Th is +2‰, in range of Cretaceous brines, as opposed to negative δ18OSMOW-fluid from meteoric, groundwater, and geothermal sites in the region and highly positive δ18OSMOW-fluid expected for mantle-derived fluids. Calcite veins at this location do not record evidence for deeply-sourced metamorphic and magmatic fluids, an observation that differs from what is reported for the NAF elsewhere along strike.

Thick-skinned tectonics in a Late Cretaceous-Neogene intracontinental belt (High Atlas Mountains, Morocco): The flat-ramp fault control on basement shortening and cover folding

NASA Astrophysics Data System (ADS)

Fekkak, A.; Ouanaimi, H.; Michard, A.; Soulaimani, A.; Ettachfini, E. M.; Berrada, I.; El Arabi, H.; Lagnaoui, A.; Saddiqi, O.

2018-04-01

Most of the structural studies of the intracontinental High Atlas belt of Morocco have dealt with the central part of the belt, whose basement does not crop out. Here we study the Alpine deformation of the North Subatlas Zone, which is the part of the Western High Atlas (WHA) Paleozoic Massif that involves both Paleozoic basement units and remnants of their Mesozoic-Cenozoic cover formations. Our aim is to better constrain the geometry and kinematics of the basement faults during the Alpine shortening. Based on detail mapping, satellite imagery and field observations, we describe an array of sub-equatorial, transverse and oblique faults between the WHA Axial Zone and the Haouz Neogene basin. They define a mosaic of basement blocks pushed upon one another and upon the Haouz basement along the North Atlas Fault (NAF). The Axial Zone makes up the hanging-wall of the Adassil-Medinet Fault (AMF) south of this mosaic. The faults generally presents flat-ramp-flat geometry linked to the activation of multiple décollement levels, either within the basement where its foliation is subhorizontal or within favourable cover formations (Jurassic evaporites, Lower Cretaceous silty red beds, Upper Cretaceous evaporitic marls, Neogene basal argillites). The occurrence of the North Atlas detachment (NAD) allowed folded pop-up units to develop in front of the propagating NAF. Shortening began as early as the Campanian-Maastrichtian along the AMF. The direction of the maximum horizontal stress rotated from NNE-SSW to NNW-SSE from the Maastrichtian-Paleocene to the Neogene. The amount of shortening reaches 20% in the Azegour transect. This compares with the shortening amount published for the central-eastern High Atlas, suggesting that similar structures characterize the Paleozoic basement all along the belt. The WHA thick-skinned tectonics evokes that of the frontal Sevier belt and of the external Western Alps, although with a much minor pre-inversion burial.

Morphotectonics of Sea of Marmara: A Basin on North Anatolian Continental Transform Plate Boundary

NASA Astrophysics Data System (ADS)

Çaǧatay, M. Namık; Uçarkuş, Gülsen; Eriş, K. Kadir; Henry, Pierre; Geli, Louis; Gasperini, Luca

2017-04-01

The Sea of Marmara is located the North Anatolian Fault (NAF), a continental transform plate boundary between the Eurasian and Anatolian-Aegean plates. The area is also under the influence of the N-S extensional Aegean regime. The 100 km-wide NAF zone in the Marmara region accommodates about 25 mm/yr dextral motion, with 70-80% of this displacement taking place along the northern branch of the NAF, the Main Marmara Fault in the Sea of Marmara. The main morphological elements of the Sea of Marmara consists of less than 100 m deep shelf areas, 1250 m three deep sub-basins (Tekirdaǧ, Central and Çınarcık) and two NE-trending pressure highs (Western and Central) separating the deep subbasins. The other elements are 800 m deep Kumburgaz Basin on the Central High, 400 m deep İmralı Basin in the south, and 100-200 m deep, E-W oriented gulfs or bays. The slopes connecting the shelf to the deep basins have slope angles ranging between 6° and 29°, and are incised by submarine canyons and marked by landslides scars. The basins have accumulated up to 6 km thick sediments. They are subsiding at a rate 5-6 mm/year and accumulating sediments at rates of 1-3 mm/yr over the last 15 ka, with the rates for the glacial periods being the 2-3 times that for interglacials. The sedimentation rates over the highs range between 0.2 and 0.4 mm/yr over the last 70 ka. The morphology of the Sea of Marmara is controlled by the NAF activity that was in turn guided a complex basement structure in the region. The basement of the Sea of Marmara region consists of various micro-continents (Istanbul Zone and Rhodope-Pontide and Sakarya continents), ophiolitic suture zones and the hydrocarbon bearing Eocene-Middle Miocene Thrace Basin on the southern margin of Rhodope-Pontide continent. After closure of the Intra-Pontide Ocean and the collision of the Sakarya and Rhodope-Pontide continents during the Oligocene-Early Miocene, the region was uplifted, and subjected to peneplanation during the mid-Late Miocene. The incipient NAF activity started about the same time, when the Marmara region was covered by shallow lakes. Initiation of crustal extension and strain localization in the Sea of Marmara area started in the Earliest Pliocene while shallow siliciclastic and carbonate sediment were deposited. Considering the rates of subsidence and sedimentation, the present day morphology of the Sea of Marmara, with its transtensional basins and the intervening highs between the splays of the NAF, developed mainly during the last 1-2 Ma. This geomorphic evolution is reviewed on the basis of published and unpublished data.

A 3000-year record of ground-rupturing earthquakes along the central North Anatolian fault near Lake Ladik, Turkey

USGS Publications Warehouse

Fraser, J.; Pigati, J.S.; Hubert-Ferrari, A.; Vanneste, K.; Avsar, U.; Altinok, S.

2009-01-01

The North Anatolian fault (NAF) is a ???1500 km long, arcuate, dextral strike-slip fault zone in northern Turkey that extends from the Karliova triple junction to the Aegean Sea. East of Bolu, the fault zone exhibits evidence of a sequence of large (Mw >7) earthquakes that occurred during the twentieth century that displayed a migrating earthquake sequence from east to west. Prolonged human occupation in this region provides an extensive, but not exhaustive, historical record of large earthquakes prior to the twentieth century that covers much of the last 2000 yr. In this study, we extend our knowledge of rupture events in the region by evaluating the stratigraphy and chronology of sediments exposed in a paleoseismic trench across a splay of the NAF at Destek, ???6:5 km east of Lake Ladik (40.868?? N, 36.121?? E). The trenched fault strand forms an uphill-facing scarp and associated sediment trap below a small catchment area. The trench exposed a narrow fault zone that has juxtaposed a sequence of weakly defined paleosols interbedded with colluvium against highly fractured bedrock. We mapped magnetic susceptibility variations on the trench walls and found evidence for multiple visually unrecognized colluvial wedges. This technique was also used to constrain a predominantly dip-slip style of displacement on this fault splay. Sediments exposed in the trench were dated using both charcoal and terrestrial gastropod shells to constrain the timing of the earthquake events. While the gastropod shells consistently yielded 14 C ages that were too old (by ???900 yr), we obtained highly reliable 14 C ages from the charcoal by dating multiple components of the sample material. Our radiocarbon chronology constrains the timing of seven large earthquakes over the past 3000 yr prior to the 1943 Tosya earthquake, including event ages of (2?? error): A.D. 1437-1788, A.D. 1034-1321, A.D. 549-719, A.D. 17-585 (1-3 events), 35 B.C.-A.D. 28, 700-392 B.C., 912-596 B.C. Our results indicate an average interevent time of 385 166?? yr (1??).

Holocene ruptures along the North Anatolia Fault in the Marmara Sea, Turkey: Sedimentary processes, spatial extent and age

NASA Astrophysics Data System (ADS)

Braudy, N.; McHugh, C. M.; Cagatay, M.; Seeber, L.; Henry, P.; Geli, L.

2010-12-01

The North Anatolian fault (NAF), which extends east west for over 1600 km across Turkey, is one of the world's major continental transforms. Since 1939, a sequence of M>7 earthquakes ruptured progressively westward the entire NAF east of Marmara. The most recent and westernmost events in this sequence, the Mw7.4 Izmit and the Mw7.2 Duzce main shocks of 1999, ruptured about 160 km of the fault and were particularly destructive (~17,000 deaths). The only portion of the NAF that did not rupture in the last century is the segment beneath the Marmara Sea that is considered a seismic gap and presents high risk to Istanbul and surroundings. To decipher Holocene earthquake ruptures and the processes leading to their signature in the sedimentary record we applied submarine paleoseismology techniques to study a transect of three 10 m long cores recovered from the Central Basin. The sediments were analyzed with x-ray radiography, for grain size variability at cm-scale, geochemical elements at mm-scale and physical properties. These measurements were calibrated to a chronology developed from short-lived radioisotopes (137-Cs, 210-Pb) and radiocarbon. Turbidites were sampled from the deepest part of the Central Basin, from 1248 to 1262 m depth. As previously documented by McHugh et al (2006), these turbidites are characterized by multiple sand and coarse silt beds, each normally graded, and that together grade upwards into a non-stratified silt that also fines upwards. Elemental concentrations of Al and Si increase with the sand and coarser silt components indicative of an influx of terrigenous components. These complex turbidites-homogenites are as thick as 1 m and dominate the sedimentation in the basin (≈80%). The remainder includes 10 to 20 cm thick fining upwards silt deposits. We interpret these depositional events to represent large earthquakes, the ones including transport of sand are proximal, and the ones without the sand are distal. We measured concentrations of Ca within the coarse component of the complex turbidite and depletion of Mn above. These elemental trends, previously documented by Cagatay et al (2008) can generally be associated with the turbidite-homogenite units and are linked to diagnetic processes resulting from diffuse fluid/gas escape during strong shaking of the sea floor or after the earthquake. Fifteen turbidites-homogenites were preserved within the past 4000 years with an average recurrence interval of 300 years. This is consistent with previous estimates and with a constant slip rate for the NAF for the mid to late Holocene. We have tentatively linked one of the turbidite-homogenite deposits to the 740 AD historical earthquake and two others to possibly the 1912 > Ms 7.4 and more distal 1963 or 1964 events Ms >6.4 linked to the Yalova and Manyas faults, respectively.

76 FR 9640 - Prevailing Rate Systems: Santa Clara, CA, Tulsa County, OK, and Angelina County, TX

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-22

... System (FWS) wage area and Angelina County, Texas, as an area of application to the Dallas, TX, NAF FWS... County, Texas, as an area of application to the Dallas, TX, NAF FWS wage area. The Federal Prevailing... area listing for the Oklahoma, OK, and Dallas, TX, NAF wage areas to read as follows: Appendix D to...

An L-band interferometric synthetic aperture radar study on the Ganos section of the north Anatolian fault zone between 2007 and 2011: Evidence for along strike segmentation and creep in a shallow fault patch.

PubMed

de Michele, Marcello; Ergintav, Semih; Aochi, Hideo; Raucoules, Daniel

2017-01-01

We utilize L-band interferometric synthetic aperture radar (InSAR) data in this study to retrieve a ground velocity map for the near field of the Ganos section of the north Anatolian fault (NAF) zone. The segmentation and creep distribution of this section, which last ruptured in 1912 to generate a moment magnitude (Mw)7.3 earthquake, remains incompletely understood. Because InSAR processing removes the mean orbital plane, we do not investigate large scale displacements due to regional tectonics in this study as these can be determined using global positioning system (GPS) data, instead concentrating on the close-to-the-fault displacement field. Our aim is to determine whether, or not, it is possible to retrieve robust near field velocity maps from stacking L-band interferograms, combining both single and dual polarization SAR data. In addition, we discuss whether a crustal velocity map can be used to complement GPS observations in an attempt to discriminate the present-day surface displacement of the Ganos fault (GF) across multiple segments. Finally, we characterize the spatial distribution of creep on shallow patches along multiple along-strike segments at shallow depths. Our results suggest the presence of fault segmentation along strike as well as creep on the shallow part of the fault (i.e. the existence of a shallow creeping patch) or the presence of a smoother section on the fault plane. Data imply a heterogeneous fault plane with more complex mechanics than previously thought. Because this study improves our knowledge of the mechanisms underlying the GF, our results have implications for local seismic hazard assessment.

An L-band interferometric synthetic aperture radar study on the Ganos section of the north Anatolian fault zone between 2007 and 2011: Evidence for along strike segmentation and creep in a shallow fault patch

PubMed Central

Ergintav, Semih; Aochi, Hideo; Raucoules, Daniel

2017-01-01

We utilize L-band interferometric synthetic aperture radar (InSAR) data in this study to retrieve a ground velocity map for the near field of the Ganos section of the north Anatolian fault (NAF) zone. The segmentation and creep distribution of this section, which last ruptured in 1912 to generate a moment magnitude (Mw)7.3 earthquake, remains incompletely understood. Because InSAR processing removes the mean orbital plane, we do not investigate large scale displacements due to regional tectonics in this study as these can be determined using global positioning system (GPS) data, instead concentrating on the close-to-the-fault displacement field. Our aim is to determine whether, or not, it is possible to retrieve robust near field velocity maps from stacking L-band interferograms, combining both single and dual polarization SAR data. In addition, we discuss whether a crustal velocity map can be used to complement GPS observations in an attempt to discriminate the present-day surface displacement of the Ganos fault (GF) across multiple segments. Finally, we characterize the spatial distribution of creep on shallow patches along multiple along-strike segments at shallow depths. Our results suggest the presence of fault segmentation along strike as well as creep on the shallow part of the fault (i.e. the existence of a shallow creeping patch) or the presence of a smoother section on the fault plane. Data imply a heterogeneous fault plane with more complex mechanics than previously thought. Because this study improves our knowledge of the mechanisms underlying the GF, our results have implications for local seismic hazard assessment. PMID:28961264

Leptin expression in breast nipple aspirate fluid (NAF) and serum is influenced by body mass index (BMI) but not by the presence of breast cancer.

PubMed

Sauter, E R; Garofalo, C; Hewett, J; Hewett, J E; Morelli, C; Surmacz, E

2004-05-01

While obesity is a known risk factor for postmenopausal breast cancer, the molecular mechanisms involved are unclear. Systemic levels of leptin, the product of the ob (obesity) gene, are increased in obese individuals (body mass index, BMI, over 25) and are higher in women than men. Leptin has been found to stimulate the growth of breast cancer cells in vitro. Our goal was to determine whether leptin was 1) present in nipple aspirate fluid (NAF), and 2) whether NAF leptin levels were associated with a) levels in serum, b) obesity, and c) breast cancer. We collected and evaluated NAF specimens from 83 subjects and serum specimens from 49 subjects. NAF leptin was detectable in 16/41 (39 %) of premenopausal and 21/42 (50 %) postmenopausal subjects. NAF leptin was significantly lower (p = 0.042) in premenopausal than postmenopausal women with a BMI < 25, but not in those with a higher BMI. NAF leptin was significantly associated with BMI in premenopausal (p = 0.011) but not in postmenopausal women. Serum leptin was associated with BMI in both premenopausal and postmenopausal women (p = 0.0001 for both). NAF and serum leptin were associated in premenopausal (p = 0.02) but not postmenopausal women. Neither NAF nor serum leptin was associated with premenopausal or postmenopausal breast cancer. Our findings include that 1) leptin is present in the breast and detectable in a subset of NAF samples, 2) NAF leptin in premenopausal but not postmenopausal women parallels serum leptin levels, and 3) neither NAF nor serum levels of leptin were associated with premenopausal or postmenopausal breast cancer.

Seismarmara experiment: results from reprocessing of selected multi-channel seismic reflection profiles

NASA Astrophysics Data System (ADS)

Cetin, S.; Voogd, B.; Carton, H.; Laigle, M.; Becel, A.; Saatcilar, R.; Singh, S.; Hirn, A.

2003-04-01

The North Anatolian Fault (NAF) has been responsible for the earthquakes of Izmit and Duzce in 1999. The occurrence of these earthquakes has drawn scientific attention into the Sea of Marmara since the NAF enters into the Sea of Marmara where the latest Izmit earthquake rupture stopped. The SEISMARMARA-2001 survey is a combined seismic reflection, refraction and earthquake experiment carried out in 2001 in the Marmara Region in Turkey by French-Turkish scientific cooperation. The objectives of this survey were to image the various branches of the NAF and related other fault systems. R/V Le Nadir was equipped with a 4.5 km long streamer with 360 channels and a large airgun source. During Leg 1, a grid of large regional lines encompassing the whole Marmara trough was shot. For part of them a strong 8100 cu.in. source for deepest penetration was used, with a 150 m shot interval giving a 15-fold coverage. Another part was shot for a higher resolution with a 2900 cu. in. array at a 50m or 38 m interval to give a 45 or 60-fold coverage. The latter acquisition parameters were used for Leg 2 that was devoted to a very dense grid of lines in the Cinarcik Basin Reprocessing of the multi-channel seismic data is currently being undertaken in several Institutions using different seismic processing softwares (GeoVecteur, ProMAX, Focus), to take advantage of the diverse acquisitions and cope with their limitations, for instance high fold-order for Leg 2 and strength of signal but loose spatial sampling for the bigger source. The main objectives of the reprocessing of the selected profiles are to do a detailed velocity analysis and stacking after deconvolution, filtering to remove or suppress deep sea bottom multiples and out of plane reflections, and time-migration and depth conversion and thus reveal both the shallow and deeper reflection image of the crust in the Sea of Marmara. We show that choosing an appropriate processing sequence for different sources and acquisition geometries makes it possible to obtain an enhanced image of different targets such as faults, basins with several seconds of sedimentary infill, lower crust and Moho structure. Along selected lines reflected events from the top of lower crust and the Moho boundary (7 to 12 seconds two-way time) have been identified and will contribute together with wide-angle data recorded at fixed receivers (OBS and land stations) to a joint structural and velocity model at crustal scale. Improved images shed light on the tectonic evolution of the Marmara Sea at crustal scale and contribute to its discussion in terms of structure and earthquake activity.

77 FR 63205 - Prevailing Rate Systems; Abolishment of Montgomery, Pennsylvania, as a Nonappropriated Fund...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-16

... Montgomery, Pennsylvania, as a Nonappropriated Fund Federal Wage System Wage Area AGENCY: U.S. Office of... final rule to abolish the Montgomery, Pennsylvania, nonappropriated fund (NAF) Federal Wage System (FWS) wage area and redefine Chester, Montgomery, and Philadelphia Counties, PA, to the Burlington, NJ, NAF...

76 FR 31785 - Prevailing Rate Systems; Abolishment of Cumberland, ME, as a Nonappropriated Fund Federal Wage...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-02

... of Cumberland, ME, as a Nonappropriated Fund Federal Wage System Wage Area AGENCY: U.S. Office of... (NAF) Federal Wage System (FWS) wage area and redefine Cumberland, Kennebec, and Penobscot Counties, ME, to the York, ME, NAF wage area. Aroostook, Hancock, Knox, Sagadahoc, and Washington Counties, ME...

76 FR 70321 - Prevailing Rate Systems; Abolishment of Cumberland, ME, as a Nonappropriated Fund Federal Wage...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-14

... abolish the Cumberland, Maine, nonappropriated fund (NAF) Federal Wage System (FWS) wage area and redefine... closure of the Naval Air Station Brunswick left the Cumberland wage area without an activity having the... Cumberland, Maine, nonappropriated fund (NAF) Federal Wage System (FWS) wage area and redefine Cumberland...

The central branch of the North Anatolian Fault In The Southern Marmara Sea: Evidence for a distributed, Holocene-active fault system

NASA Astrophysics Data System (ADS)

Barın, Burcu; Okay, Seda; Çifçi, Günay; Dondurur, Derman; Cormier, Marie Helene; Sorlien, Christopher; Meriç İlkimen, Elif

2015-04-01

The North Anatolian Fault (NAF) is a major right-lateral transform fault in northern Turkey that branches westward into several strands in the vicinity of the Sea of Marmara. The main northern branch bisects the Marmara Sea from east to west, and seismic reflection profiles acquired over the past 15 years have revealed its complex geometry. Further, the several basins that developed along that branch record stratigraphic sequences that provide the needed framework to interpret the relative timing of tectonic deformation in the Marmara Sea. In contrast, the central branch, which snakes across the shallow southern shelf of the Marmara Sea, has been much less investigated. Here, we analyze a comprehensive dataset of high-resolution multi-channel, sparker, and CHIRP seismic profiles, which were collected with the facilities of Seismic Laboratory (SeisLab) in the Institute of Marine Sciences and Technology and R/V K. Piri Reis belonging to Dokuz Eylül University, along the central branch in 2008 (TAMAM expedition) and in 2013-2014 (SoMAR expedition), within the framework of a bilateral TÜBİTAK - NSF project. In combination with other existing seismic profiles, these new data reveal that the Central Branch consists of multiple faults strands that are distributed across the broad southern shelf. They also reveal that many of these strands are Holocene-active, although they slip at slower rates than the northern branch and are associated with slower basin subsidence or local uplift. Lastly, seismic data image a system of half-grabens across the southern shelf that are associated with the strands of the central branch. Strata within these half-grabens are progressively tilted and consistently dip to the south. Further analysis will be conducted to determine whether the formation of these grabens are controlled by oblique slip on the strands of the central branch, or by slip on detachment faults beneath the southern shelf.

Novel duplex vapor-electrochemical method for silicon solar cells. [reaction of fluorine and silicon compounds with sodium

NASA Technical Reports Server (NTRS)

Nanis, L.; Sanjurjo, A.; Sancier, K. M.; Bartlett, R.; Westphal, S.

1979-01-01

The dependence of the SiF4 Na reaction initiation time and of the efficiency of the reaction on Na particle size and reaction temperature were studied. Close to 100 percent utilization of Na was obtained, and formation of byproduct fluoro-silicate was decreased to below 10 percent. A SiF4 Na reactor was built to scale up the reaction by a factor of about four and is now being tested. A scaled up melting system was built and successfully used to separate Si from kilogram quantities of SiF4 NaF mixtures. Support studies of the volatilization of NaF performed in a smaller melting system indicated minimal loss of NaF as vapor at 1410 C. The wetting of graphite was also investigated to determine the constituents of the NaF phase which promote good wetting.

Possible worst-case tsunami scenarios around the Marmara Sea from combined earthquake and landslide sources

NASA Astrophysics Data System (ADS)

Latcharote, Panon; Suppasri, Anawat; Imamura, Fumihiko; Aytore, Betul; Yalciner, Ahmet Cevdet

2016-12-01

This study evaluates tsunami hazards in the Marmara Sea from possible worst-case tsunami scenarios that are from submarine earthquakes and landslides. In terms of fault-generated tsunamis, seismic ruptures can propagate along the North Anatolian Fault (NAF), which has produced historical tsunamis in the Marmara Sea. Based on the past studies, which consider fault-generated tsunamis and landslide-generated tsunamis individually, future scenarios are expected to generate tsunamis, and submarine landslides could be triggered by seismic motion. In addition to these past studies, numerical modeling has been applied to tsunami generation and propagation from combined earthquake and landslide sources. In this study, tsunami hazards are evaluated from both individual and combined cases of submarine earthquakes and landslides through numerical tsunami simulations with a grid size of 90 m for bathymetry and topography data for the entire Marmara Sea region and validated with historical observations from the 1509 and 1894 earthquakes. This study implements TUNAMI model with a two-layer model to conduct numerical tsunami simulations, and the numerical results show that the maximum tsunami height could reach 4.0 m along Istanbul shores for a full submarine rupture of the NAF, with a fault slip of 5.0 m in the eastern and western basins of the Marmara Sea. The maximum tsunami height for landslide-generated tsunamis from small, medium, and large of initial landslide volumes (0.15, 0.6, and 1.5 km3, respectively) could reach 3.5, 6.0, and 8.0 m, respectively, along Istanbul shores. Possible tsunamis from submarine landslides could be significantly higher than those from earthquakes, depending on the landslide volume significantly. These combined earthquake and landslide sources only result in higher tsunami amplitudes for small volumes significantly because of amplification within the same tsunami amplitude scale (3.0-4.0 m). Waveforms from all the coasts around the Marmara Sea indicate that other residential areas might have had a high risk of tsunami hazards from submarine landslides, which can generate higher tsunami amplitudes and shorter arrival times, compared to Istanbul.

Fluoride induces apoptosis in H9c2 cardiomyocytes via the mitochondrial pathway.

PubMed

Yan, Xiaoyan; Wang, Lu; Yang, Xia; Qiu, Yulan; Tian, Xiaolin; Lv, Yi; Tian, Fengjie; Song, Guohua; Wang, Tong

2017-09-01

Numerous studies have shown that chronic excessive fluoride intake can adversely affect different organ systems. In particular, the cardiovascular system is susceptible to disruption by a high concentration of fluoride. The objectives of this study were to explore the mechanism of apoptosis by detecting the toxic effects of different concentrations of sodium fluoride (NaF) in H9c2 cells exposed for up to 96 h. NaF not only inhibited H9c2 cell proliferation but also induced apoptosis and morphological damage. With increasing NaF concentrations, early apoptosis of H9c2 cells was increased while the mitochondrial membrane potential was decreased. Compared with the control group, the mRNA levels of caspase-3, caspase-9, and cytochrome c all increased with increasing concentrations of NaF. In summary, these data suggest that apoptosis is involved in NaF-induced H9c2 cell toxicity and that activation of the mitochondrial pathway may occur. Copyright © 2017 Elsevier Ltd. All rights reserved.

The role of deterministic analyses and seismotectonic data in earthquake risk assessment, Istanbul, Turkey.

NASA Astrophysics Data System (ADS)

Pondard, Nicolas; Armijo, Rolando; King, Geoffrey C. P.; Meyer, Bertrand; Ucarkus, Gulsen

2010-05-01

Seismotectonic methods allowing quantitative measures of the frequency and severity of earthquakes have greatly advanced over the last 30 years, aided by high-resolution imagery, digital topography and modern techniques for dating. During the same period, deterministic models based on the physics of earthquakes (Coulomb stress interactions) have been extensively developed to explain the distribution of earthquakes in space and time. Seismotectonic data and Coulomb Stress models provide valuable information on seismic hazard and could assist the public policy, disaster risk management and financial risk transfer communities to make more informed decisions around their strategic planning and risk management activities. The Sea of Marmara and Istanbul regions (North Anatolian Fault, NAF) are among the most appropriate on Earth to analyse seismic hazard, because reliable data covers almost completely two seismic cycles (the past ~500 years). Earthquake ruptures associated with historical events have been found in the direct vicinity of the city, on the Marmara sea floor. The MARMARASCARPS cruise using an unmanned submersible (ROV) provides direct observations to study the morphology and geology of those ruptures, their distribution and geometry. These observations are crucial to quantify the magnitude of past earthquakes along the submarine fault system (e.g. 1894, 1912, 1999, M > 7). In particular, the identification of a break continuous over 60 km with a right-lateral slip of 5 m, corresponding probably to the offshore extension of the Ganos earthquake rupture (1912, Ms 7.4), modifies substantially our understanding of the current state of loading along the NAF next to Istanbul. Coulomb stress analysis is used to characterise loading evolution in well-identified fault segments, including secular loading from below and lateral loading imposed by the occurrence of previous earthquakes. The 20th century earthquake sequence in the region of Istanbul is modelled using geological and geophysical records. For the 18th century M≥7.0 earthquake clusters, we construct scenarios consistent with the tectonic and historical data. Coulomb stress modeling including the 20th and 18th century historical events shows a current zone of maximum loading along a 70 km long strike-slip segment, south-west of Istanbul, with at least 4-5 m of slip deficit. That segment alone would be capable of generating a large magnitude earthquake (Mw 7.2). Other segments in Marmara appear less loaded.

Performance and age of African and non-African runners in half- and full marathons held in Switzerland, 2000–2010

PubMed Central

Aschmann, André; Knechtle, Beat; Cribari, Marco; Rüst, Christoph Alexander; Onywera, Vincent; Rosemann, Thomas; Lepers, Romuald

2013-01-01

Background Endurance running performance of African (AF) and non-African (NAF) athletes is investigated, with better performances seen for Africans. To date, no study has compared the age of peak performance between AF and NAF runners. The present research is an analysis of the age and running performance of top AF and NAF athletes, using the hypothesis that AF athletes were younger and faster than NAF athletes. Methods Age and performance of male and female AF and NAF athletes in half-marathons and marathons held in Switzerland in 2000–2010 were investigated using single and multilevel hierarchical regression analyses. Results For half-marathons, male NAF runners were older than male AF runners (P = 0.02; NAF, 31.1 years ± 6.4 years versus AF, 26.2 years ± 4.9 years), and their running time was longer (P = 0.02; NAF, 65.3 minutes ± 1.7 minutes versus AF, 64.1 minutes ± 0.9 minutes). In marathons, differences between NAF and AF male runners in age (NAF, 33.0 years ± 4.8 years versus AF, 28.6 years ± 3.8 years; P < 0.01) and running time (NAF, 139.5 minutes ± 5.6 minutes versus AF, 133.3 minutes ± 2.7 minutes; P < 0.01) were more pronounced. There was no difference in age (NAF, 31.0 years ± 7.0 years versus AF, 26.7 years ± 6.0 years; P > 0.05) or running time (NAF, 75.0 minutes ± 3.7 minutes versus AF, 75.6 minutes ± 5.3 minutes; P > 0.05) between NAF and AF female half-marathoners. For marathoners, NAF women were older than AF female runners (P = 0.03; NAF, 31.6 years ± 4.8 years versus AF, 27.8 years ± 5.3 years), but their running times were similar (NAF, 162.4 minutes ± 7.2 minutes versus AF, 163.0 minutes ± 7.0 minutes; P > 0.05). Conclusion In Switzerland, the best AF male half-marathoners and marathoners were younger and faster than the NAF counterpart runners. In contrast to the results seen in men, AF and NAF female runners had similar performances. Future studies need to investigate performance and age of AF and NAF marathoners in the World Marathon Majors Series. PMID:24379724

Need for denser geodetic network to get real constrain on the fault behavior along the Main Marmara Sea segments of the NAF, toward an optimized GPS network.

NASA Astrophysics Data System (ADS)

Klein, E.; Masson, F.; Duputel, Z.; Yavasoglu, H.; Agram, P. S.

2016-12-01

Over the last two decades, the densification of GPS networks and the development of new radar satellites offered an unprecedented opportunity to study crustal deformation due to faulting. Yet, submarine strike slip fault segments remain a major issue, especially when the landscape appears unfavorable to the use of SAR measurements. It is the case of the North Anatolian fault segments located in the Main Marmara Sea, that remain unbroken ever since the Mw7.4 earthquake of Izmit in 1999, which ended a eastward migrating seismic sequence of Mw > 7 earthquakes. Located directly offshore Istanbul, evaluation of seismic hazard appears capital. But a strong controversy remains over whether these segments are accumulating strain and are likely to experience a major earthquake, or are creeping, resulting both from the simplicity of current geodetic models and the scarcity of geodetic data. We indeed show that 2D infinite fault models cannot account for the complexity of the Marmara fault segments. But current geodetic data in the western region of Istanbul are also insufficient to invert for the coupling using a 3D geometry of the fault. Therefore, we implement a global optimization procedure aiming at identifying the most favorable distribution of GPS stations to explore the strain accumulation. We present here the results of this procedure that allows to determine both the optimal number and location of the new stations. We show that a denser terrestrial survey network can indeed locally improve the resolution on the shallower part of the fault, even more efficiently with permanent stations. But data closer from the fault, only possible by submarine measurements, remain necessary to properly constrain the fault behavior and its potential along strike coupling variations.

Differences in transcriptional effects of 1α,25 dihydroxyvitamin D3 on fibroblasts associated to breast carcinomas and from paired normal breast tissues.

PubMed

Campos, Laura Tojeiro; Brentani, Helena; Roela, Rosimeire Aparecida; Katayama, Maria Lucia Hirata; Lima, Leandro; Rolim, Cíntia Flores; Milani, Cíntia; Folgueira, Maria Aparecida Azevedo Koike; Brentani, Maria Mitzi

2013-01-01

The effects of 1α,25 dihydroxyvitamin D3 (1,25D) on breast carcinoma associated fibroblasts (CAFs) are still unknown. This study aimed to identify genes whose expression was altered after 1,25D treatment in CAFs and matched adjacent normal mammary associated fibroblasts (NAFs). CAFs and NAFs (from 5 patients) were cultured with or without (control) 1,25D 100 nM. Both CAF and NAF expressed vitamin D receptor (VDR) and 1,25D induction of the genomic pathway was detected through up-regulation of the target gene CYP24A1. Microarray analysis showed that despite presenting 50% of overlapping genes, CAFs and NAFs exhibited distinct transcriptional profiles after 1,25D treatment (FDR<0.05). Functional analysis revealed that in CAFs, genes associated with proliferation (NRG1, WNT5A, PDGFC) were down regulated and those involved in immune modulation (NFKBIA, TREM-1) were up regulated, consistent with anti tumor activities of 1,25D in breast cancer. In NAFs, a distinct subset of genes was induced by 1,25D, involved in anti apoptosis, detoxification, antibacterial defense system and protection against oxidative stress, which may limit carcinogenesis. Co-expression network and interactome analysis of genes commonly regulated by 1,25D in NAFs and CAFs revealed differences in their co-expression values, suggesting that 1,25D effects in NAFs are distinct from those triggered in CAFs. Copyright © 2012 Elsevier Ltd. All rights reserved.

Identification of salt-alloy combinations for thermal energy storage applications in advanced solar dynamic power systems

NASA Technical Reports Server (NTRS)

Whittenberger, J. D.; Misra, A. K.

1987-01-01

Thermodynamic calculations based on the available data for flouride salt systems reveal that a number of congruently melting compositions and eutectics exist which have the potential to meet the lightweight, high energy storage requirements imposed for advanced solar dynamic systems operating between about 1000 and 1400 K. Compatibility studies to determine suitable containment alloys to be used with NaF-22CaF2-13MgF2, NaF-32CaF2, and NaF-23MgF2 have been conducted at the eutectic temperature + 25 K for each system. For these three NaF-based eutectics, none of the common, commercially available high temperature alloys appear to offer adequate corrosion resistance for a long lifetime; however mild steel, pure nickel and Nb-1Zr could prove useful. These latter materials suggest the possibility that a strong, corrosion resistant, nonrefractory, elevated temperature alloy based on the Ni-Ni3Nb system could be developed.

Preliminary Obtained Data from Borehole Geodetic Measurements in Marmara Region, Turkey

NASA Astrophysics Data System (ADS)

Ozener, H.; Aktug, B.; Karabulut, H.; Ergintav, S.; Dogru, A.; Yilmaz, O.; Turgut, B.; Ahiska, B.; Mencin, D.; Mattioli, G. S.

2014-12-01

Dense continuous GPS networks quantify the time-dependent deformation field of the earthquake cycle. However the strainmeters can capture signals with superior precision at local spatial scales, in particular in the short-period, from minutes to a month. Many relatively small-scale events (e.i. SSEs, creeps) have been successfully determined on the subduction zones. Istanbul located near the most active parts of the North Anatolian Fault (NAF) has been monitored by different observing techniques such as seismic networks and continuous/survey-mode GPS networks for decades. However, it is still essential to observe deformation in a broad range of temporal and spatial scales (from seismology to geodesy and to geology). Borehole strainmeters are very sensitive to deformation in the range of less than a month. In this study, we present a new project, financially and technically supported by Istanbul Development Agency (ISTKA) and UNAVCO, respectively, which includes the installation of two borehole strainmeters are being deployed in European side of Istanbul in Marmara Region. Since these instruments can also respond to non-tectonic processes, it is necessary to have more instruments to increase spatial coherence and to have additional sensors to detect and model noise (such as barometric pressure, tides, or precipitation). The introduced monitoring system will provide significant insight about the creeping phenomenon and the possible SSE to our understanding of seismic hazards in active zones and possible precursors. Our long term objective is to build a borehole monitoring system in the region. By integrating various data obtained from borehole observations, we expect to get a better understanding of dynamics in the western NAF. In this presentation, we introduce data and ongoing analysis obtained with strainmeters.

Lipid Emulsion Inhibits Vasodilation Induced by a Toxic Dose of Bupivacaine via Attenuated Dephosphorylation of Myosin Phosphatase Target Subunit 1 in Isolated Rat Aorta

PubMed Central

Ok, Seong-Ho; Byon, Hyo-Jin; Kwon, Seong-Chun; Park, Jungchul; Lee, Youngju; Hwang, Yeran; Baik, Jiseok; Choi, Mun-Jeoung; Sohn, Ju-Tae

2015-01-01

Lipid emulsions are widely used for the treatment of systemic toxicity that arises from local anesthetics. The goal of this in vitro study was to examine the cellular mechanism associated with the lipid emulsion-mediated attenuation of vasodilation induced by a toxic dose of bupivacaine in isolated endothelium-denuded rat aorta. The effects of lipid emulsion on vasodilation induced by bupivacaine, mepivacaine, and verapamil were assessed in isolated aorta precontracted with phenylephrine, the Rho kinase stimulant NaF, and the protein kinase C activator phorbol 12,13-dibutyrate (PDBu). The effects of Rho kinase inhibitor Y-27632 on contraction induced by phenylephrine or NaF were assessed. The effects of bupivacaine on intracellular calcium concentrations ([Ca2+]i) and tension induced by NaF were simultaneously measured. The effects of bupivacaine alone and lipid emulsion plus bupivacaine on myosin phosphatase target subunit 1 (MYPT1) phosphorylation induced by NaF were examined in rat aortic vascular smooth muscle cells. In precontracted aorta, the lipid emulsion attenuated bupivacaine-induced vasodilation but had no effect on mepivacaine-induced vasodilation. Y-27632 attenuated contraction induced by either phenylephrine or NaF. The lipid emulsion attenuated verapamil-induced vasodilation. Compared with phenylephrine-induced precontracted aorta, bupivacaine-induced vasodilation was slightly attenuated in NaF-induced precontracted aorta. The magnitude of the bupivacaine-induced vasodilation was higher than that of a bupivacaine-induced decrease in [Ca2+]i. Bupivacaine attenuated NaF-induced MYPT1 phosphorylation, whereas lipid emulsion pretreatment attenuated the bupivacaine-induced inhibition of MYPT1 phosphorylation induced by NaF. Taken together, these results suggest that lipid emulsions attenuate bupivacaine-induced vasodilation via the attenuation of inhibition of MYPT1 phosphorylation evoked by NaF. PMID:26664257

40 CFR Appendix 7 to Subpart A of... - Determination of the Amount of Non-Aqueous Drilling Fluid (NAF) Base Fluid From Drill Cuttings by...

Code of Federal Regulations, 2013 CFR

2013-07-01

... multiplying the density of the small volume NAF-cuttings discharges (ρsvd) times the volume of the small...-cuttings discharges (kg) ρsvd = density of the small volume NAF-cuttings discharges (kg/bbl) VSVD = volume of the small volume NAF-cuttings discharges (bbl) The density of the small volume NAF-cuttings...

40 CFR Appendix 7 to Subpart A of... - Determination of the Amount of Non-Aqueous Drilling Fluid (NAF) Base Fluid From Drill Cuttings by...

Code of Federal Regulations, 2014 CFR

2014-07-01

... multiplying the density of the small volume NAF-cuttings discharges (ρsvd) times the volume of the small...-cuttings discharges (kg) ρsvd = density of the small volume NAF-cuttings discharges (kg/bbl) VSVD = volume of the small volume NAF-cuttings discharges (bbl) The density of the small volume NAF-cuttings...

40 CFR Appendix 7 to Subpart A of... - Determination of the Amount of Non-Aqueous Drilling Fluid (NAF) Base Fluid From Drill Cuttings by...

Code of Federal Regulations, 2012 CFR

2012-07-01

... multiplying the density of the small volume NAF-cuttings discharges (ρsvd) times the volume of the small...-cuttings discharges (kg) ρsvd = density of the small volume NAF-cuttings discharges (kg/bbl) VSVD = volume of the small volume NAF-cuttings discharges (bbl) The density of the small volume NAF-cuttings...

HIV-1 Nef-associated Factor 1 Enhances Viral Production by Interacting with CRM1 to Promote Nuclear Export of Unspliced HIV-1 gag mRNA.

PubMed

Ren, Xiao-Xin; Wang, Hai-Bo; Li, Chuan; Jiang, Jin-Feng; Xiong, Si-Dong; Jin, Xia; Wu, Li; Wang, Jian-Hua

2016-02-26

HIV-1 depends on host-cell-encoded factors to complete its life cycle. A comprehensive understanding of how HIV-1 manipulates host machineries during viral infection can facilitate the identification of host targets for antiviral drugs or gene therapy. The cellular protein Naf1 (HIV-1 Nef-associated factor 1) is a CRM1-dependent nucleo-cytoplasmic shuttling protein, and has been identified to regulate multiple receptor-mediated signal pathways in inflammation. The cytoplasm-located Naf1 can inhibit NF-κB activation through binding to A20, and the loss of Naf1 controlled NF-κB activation is associated with multiple autoimmune diseases. However, the effect of Naf1 on HIV-1 mRNA expression has not been characterized. In this study we found that the nucleus-located Naf1 could promote nuclear export of unspliced HIV-1 gag mRNA. We demonstrated that the association between Naf1 and CRM1 was required for this function as the inhibition or knockdown of CRM1 expression significantly impaired Naf1-promoted HIV-1 production. The mutation of Naf1 nuclear export signals (NESs) that account for CRM1 recruitment for nuclear export decreased Naf1 function. Additionally, the mutation of the nuclear localization signal (NLS) of Naf1 diminished its ability to promote HIV-1 production, demonstrating that the shuttling property of Naf1 is required for this function. Our results reveal a novel role of Naf1 in enhancing HIV-1 production, and provide a potential therapeutic target for controlling HIV-1 infection. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Effect of NaF, SnF(2), and TiF(4) Toothpastes on Bovine Enamel and Dentin Erosion-Abrasion In Vitro.

PubMed

Comar, Lívia Picchi; Gomes, Marina Franciscon; Ito, Naiana; Salomão, Priscila Aranda; Grizzo, Larissa Tercília; Magalhães, Ana Carolina

2012-01-01

The aim of this study was to compare the effect of toothpastes containing TiF(4), NaF, and SnF(2) on tooth erosion-abrasion. Bovine enamel and dentin specimens were distributed into 10 groups (n = 12): experimental placebo toothpaste (no F); NaF (1450 ppm F); TiF(4) (1450 ppm F); SnF(2) (1450 ppm F); SnF(2) (1100 ppm F) + NaF (350 ppm F); TiF(4) (1100 ppm F) + NaF (350 ppm F); commercial toothpaste Pro-Health (SnF(2)-1100 ppm F + NaF-350 ppm F, Oral B); commercial toothpaste Crest (NaF-1.500 ppm F, Procter & Gamble); abrasion without toothpaste and only erosion. The erosion was performed 4 × 90 s/day (Sprite Zero). The toothpastes' slurries were applied and the specimens abraded using an electric toothbrush 2 × 15 s/day. Between the erosive and abrasive challenges, the specimens remained in artificial saliva. After 7 days, the tooth wear was evaluated using contact profilometry (μm). The experimental toothpastes with NaF, TiF(4), SnF(2), and Pro-Health showed a significant reduction in enamel wear (between 42% and 54%). Pro-Health also significantly reduced the dentin wear. The toothpastes with SnF(2)/NaF and TiF(4)/NaF showed the best results in the reduction of enamel wear (62-70%) as well as TiF(4), SnF(2), SnF(2)/NaF, and TiF(4)/NaF for dentin wear (64-79%) (P < 0.05). Therefore, the experimental toothpastes containing both conventional and metal fluoride seem to be promising in reducing tooth wear.

Breast cancer tumorigenicity is dependent on high expression levels of NAF-1 and the lability of its Fe-S clusters

PubMed Central

Darash-Yahana, Merav; Pozniak, Yair; Lu, Mingyang; Sohn, Yang-Sung; Karmi, Ola; Tamir, Sagi; Bai, Fang; Song, Luhua; Jennings, Patricia A.; Pikarsky, Eli; Geiger, Tamar; Onuchic, José N.; Mittler, Ron; Nechushtai, Rachel

2016-01-01

Iron–sulfur (Fe-S) proteins are thought to play an important role in cancer cells mediating redox reactions, DNA replication, and telomere maintenance. Nutrient-deprivation autophagy factor-1 (NAF-1) is a 2Fe-2S protein associated with the progression of multiple cancer types. It is unique among Fe-S proteins because of its 3Cys-1His cluster coordination structure that allows it to be relatively stable, as well as to transfer its clusters to apo-acceptor proteins. Here, we report that overexpression of NAF-1 in xenograft breast cancer tumors results in a dramatic augmentation in tumor size and aggressiveness and that NAF-1 overexpression enhances the tolerance of cancer cells to oxidative stress. Remarkably, overexpression of a NAF-1 mutant with a single point mutation that stabilizes the NAF-1 cluster, NAF-1(H114C), in xenograft breast cancer tumors results in a dramatic decrease in tumor size that is accompanied by enhanced mitochondrial iron and reactive oxygen accumulation and reduced cellular tolerance to oxidative stress. Furthermore, treating breast cancer cells with pioglitazone that stabilizes the 3Cys-1His cluster of NAF-1 results in a similar effect on mitochondrial iron and reactive oxygen species accumulation. Taken together, our findings point to a key role for the unique 3Cys-1His cluster of NAF-1 in promoting rapid tumor growth through cellular resistance to oxidative stress. Cluster transfer reactions mediated by the overexpressed NAF-1 protein are therefore critical for inducing oxidative stress tolerance in cancer cells, leading to rapid tumor growth, and drugs that stabilize the NAF-1 cluster could be used as part of a treatment strategy for cancers that display high NAF-1 expression. PMID:27621439

Breast cancer tumorigenicity is dependent on high expression levels of NAF-1 and the lability of its Fe-S clusters.

PubMed

Darash-Yahana, Merav; Pozniak, Yair; Lu, Mingyang; Sohn, Yang-Sung; Karmi, Ola; Tamir, Sagi; Bai, Fang; Song, Luhua; Jennings, Patricia A; Pikarsky, Eli; Geiger, Tamar; Onuchic, José N; Mittler, Ron; Nechushtai, Rachel

2016-09-27

Iron-sulfur (Fe-S) proteins are thought to play an important role in cancer cells mediating redox reactions, DNA replication, and telomere maintenance. Nutrient-deprivation autophagy factor-1 (NAF-1) is a 2Fe-2S protein associated with the progression of multiple cancer types. It is unique among Fe-S proteins because of its 3Cys-1His cluster coordination structure that allows it to be relatively stable, as well as to transfer its clusters to apo-acceptor proteins. Here, we report that overexpression of NAF-1 in xenograft breast cancer tumors results in a dramatic augmentation in tumor size and aggressiveness and that NAF-1 overexpression enhances the tolerance of cancer cells to oxidative stress. Remarkably, overexpression of a NAF-1 mutant with a single point mutation that stabilizes the NAF-1 cluster, NAF-1(H114C), in xenograft breast cancer tumors results in a dramatic decrease in tumor size that is accompanied by enhanced mitochondrial iron and reactive oxygen accumulation and reduced cellular tolerance to oxidative stress. Furthermore, treating breast cancer cells with pioglitazone that stabilizes the 3Cys-1His cluster of NAF-1 results in a similar effect on mitochondrial iron and reactive oxygen species accumulation. Taken together, our findings point to a key role for the unique 3Cys-1His cluster of NAF-1 in promoting rapid tumor growth through cellular resistance to oxidative stress. Cluster transfer reactions mediated by the overexpressed NAF-1 protein are therefore critical for inducing oxidative stress tolerance in cancer cells, leading to rapid tumor growth, and drugs that stabilize the NAF-1 cluster could be used as part of a treatment strategy for cancers that display high NAF-1 expression.

New Field Observations About 19 August 1966 Varto earthquake, Eastern Turkey

NASA Astrophysics Data System (ADS)

Gurboga, S.

2013-12-01

Some destructive earthquakes in the past and even in the recent have several mysteries. For example, magnitude, epicenter location, faulting type and source fault of an earthquake have not been detected yet. One of these mysteries events is 19 August 1966 Varto earthquake in Turkey. 19 August 1966 Varto earthquake (Ms = 6.8) was an extra ordinary event at the 40 km east of junction between NAFS and EAFS which are two seismogenic system and active structures shaping the tectonics of Turkey. This earthquake sourced from Varto fault zone which are approximately 4 km width and 43 km length. It consists of faults which have parallel to sub-parallel, closely-spaced, north and south-dipping up to 85°-88° dip amount. Although this event has 6.8 (Ms) magnitude that is big enough to create a surface rupture, there was no clear surface deformation had been detected. This creates the controversial issue about the source fault and the mechanism of the earthquake. According to Wallace (1968) the type of faulting is right-lateral. On the other hand, McKenzie (1972) proposed right-lateral movement with thrust component by using the focal mechanism solution. The recent work done by Sançar et al. (2011) claimed that type of faulting is pure right-lateral strike-slip and there is no any surface rupture during the earthquake. Furthermore, they suggested that Varto segment in the Varto Fault Zone was most probably not broken in 1966 earthquake. This study is purely focused on the field geology and trenching survey for the investigation of 1966 Varto earthquake. Four fault segments have been mapped along the Varto fault zone: Varto, Sazlica, Leylekdağ and Çayçati segments. Because of the thick volcanic cover on the area around Varto, surface rupture has only been detected by trenching survey. Two trenching survey have been applied along the Yayikli and Ağaçalti faults in the Varto fault zone. Consequently, detailed geological work in the field and trenching survey indicate that a) source of 1966 earthquake is Varto segment in Varto Fault Zone, b) many of the surface deformations observed just after the earthquake is lateral-spreading and small landslides, c) surface rupture was created with 10 cm displacement at the surface with thrust component. Because of the volcanic cover and activation of many faults, ground surface rupture could not be seen clearly which has been expected after 6.8 magnitude earthquake, d) faulting type is right-lateral component with thrust component. Keywords: 1966 Varto earthquake, paleoseismology, right-lateral fault with thrust component.

Quantification of fluvial response to tectonic deformation in the Central Pontides, Turkey; inferences from OSL dating of fluvial terraces

NASA Astrophysics Data System (ADS)

McClain, Kevin; Yıldırım, Cengiz; Çiner, Attila; Akif Sarıkaya, M.; Şahin, Sefa; Özcan, Orkan; Güneç Kıyak, Nafiye; Öztürk, Tuǧba

2017-04-01

From Late Miocene to present, Anatolia's rapid counterclockwise movement, which increases in velocity towards the Hellenic Arc, has formed the North Anatolian Fault (NAF), a dextral transform fault along the Anatolia-Eurasia plate boundary and the northern margin of the Central Anatolian Plateau (CAP). A zone of transpression referred to as the Central Pontides exists between the broad restraining bend of the NAF and the Black Sea Basin, uplifting what is interpreted as a detached flower structure. Dating of Quaternary landforms in the eastern flank of the Central Pontides has helped to understand its recent deformation. However, in the western flank of the Central Pontides there is an absence of Quaternary studies, relatively quiet modern seismicity, and difficulties locating or observing fault scarps. This led us to use optically stimulated luminescence dating (OSL-dating) of fluvial terrace sediments and the study of geomorphic features to gain insight into the influence of climate and tectonics on landscape evolution of this area. In this area, the Filyos River crosses the Karabük Fault (reverse fault) and deeply incises a gorge through the Karabük Range before flowing towards the Black Sea. In the gorge an abundance of indicators of tectonic deformation were mapped, such as hanging valleys, wind gaps, bedrock gorges, landslides, steep V-shaped channels, tilted basins, as well as fluvial strath terraces. In particular, strath terraces of at least 8 levels within just 1.5 km of horizontal distance were examined. We used OSL-dating to estimate five deposition ages of fluvial strath terrace sediments, leading to an estimation of incision and uplift rates over time. Using three samples per terrace with strath elevations of 246 ± 0.2 m, 105.49 ± 0.2 m, 43.6 ± 0.2 m, 15.3 ± 0.2 m and 3.6 ± 0.2 m above the Filyos River, we determined corresponding ages of 841 ± 76 ka, 681 ± 49 ka, 386 ± 18 ka, 88 ± 5.1 ka and 50.9 ± 2.8 ka. Incision rates over time (oldest terrace to youngest) suggest uplift of 0.29 ± 0.03 mm/y, 0.16 ± 0.01 mm/y, 0.10 ± 0.01 mm/y, 0.17 ± 0.01 mm/y and 0.07 ± 0.004 mm/y. Collectively, our ages infer decelerating fluvial incision and rock uplift rates in the Karabük Range of the Central Pontides. The highest rate that belongs to oldest terrace level (841 ± 76 ka) also implies long-term mean uplift, which is well correlated with long term ( 350 ka) mean uplift rate obtained from fluvial terraces in the eastern flank of the (Gökırmak Basin) Central Pontides. These results indicate Quaternary activity of the Karabük Fault despite the fact that very low modern seismicity and partition of strain in the north of the North Anatolian Fault. Keywords: Tectonics, Geomorphology, Fluvial Terrace, OSL Dating, Central Pontides, North Anatolian Fault, Filyos River, Turkey, Central Anatolian Plateau

A point mutation in the [2Fe–2S] cluster binding region of the NAF-1 protein (H114C) dramatically hinders the cluster donor properties

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

Tamir, Sagi; Eisenberg-Domovich, Yael; Conlan, Andrea R.

2014-06-01

NAF-1 has been shown to be related with human health and disease, is upregulated in epithelial breast cancer and suppression of its expression significantly suppresses tumor growth. It is shown that replacement of the single His ligand with Cys resulted in dramatic changes to the properties of its 2Fe-2S clusters without any global crystal structural changes. NAF-1 is an important [2Fe–2S] NEET protein associated with human health and disease. A mis-splicing mutation in NAF-1 results in Wolfram Syndrome type 2, a lethal childhood disease. Upregulation of NAF-1 is found in epithelial breast cancer cells, and suppression of NAF-1 expression bymore » knockdown significantly suppresses tumor growth. Key to NAF-1 function is the NEET fold with its [2Fe–2S] cluster. In this work, the high-resolution structure of native NAF-1 was determined to 1.65 Å resolution (R factor = 13.5%) together with that of a mutant in which the single His ligand of its [2Fe–2S] cluster, His114, was replaced by Cys. The NAF-1 H114C mutant structure was determined to 1.58 Å resolution (R factor = 16.0%). All structural differences were localized to the cluster binding site. Compared with native NAF-1, the [2Fe–2S] clusters of the H114C mutant were found to (i) be 25-fold more stable, (ii) have a redox potential that is 300 mV more negative and (iii) have their cluster donation/transfer function abolished. Because no global structural differences were found between the mutant and the native (wild-type) NAF-1 proteins, yet significant functional differences exist between them, the NAF-1 H114C mutant is an excellent tool to decipher the underlying biological importance of the [2Fe–2S] cluster of NAF-1 in vivo.« less

Age of the North Anatolian Fault Segments in the Yalova with U/Th Dating Method by Travertine Data

NASA Astrophysics Data System (ADS)

Selim, Haluk; Ömer Taş, K.

2016-04-01

Travertine occurrences developed along the segments of the North Anatolian Fault (NAF) in the south of Yalova. Travertines outcrop approximately 1 km2 area. These are middle-thick bedded approximately 20-40 m and back-tilted southward or horizontally. Lithology of travertines deposited such as physolite, stalactites-stalagmites, cave pearls, sharp pebble carbonate nodules, spherical-roller-intricate shapes or laminated banded travertine. Geochemical analyses were performed on the six samples of the travertines. X-ray analysis indicates that all samples are entirely composed of low-Mg calcite. Banded travertines with some tubular structures formed by precipitation from rising hot water are best developed near the toes of the large, hanging-wall-derived alluvial fans, whereas phreatic cement preferentially exists in footwall-derived, alluvial-fan conglomerates. The unit developed clarity which is controlled by normal fault as the structural and morphological, relationship with active tectonics. The travertines are a range-front type. U/Th series age dating results indicate that the travertine deposition extends back to 155 ka and yields ages of 60.000 (± 3, 091) to 153.149 (±13,466) from the range-front type travertines.

Determination of Aseismic Creep or Strain Field on the Main Marmara Fault

NASA Astrophysics Data System (ADS)

Özbey, V.; Yavasoglu, H.; Masson, F.; Klein, E.; Alkan, M. N.; Alkan, R. M.

2016-12-01

Plate motion affecting the Earth's crust have occurred for millions of years. Determination of strain accumulation based on the plate motion is commonly monitored with GPS in recent years. The North Anatolian Fault (NAF) Zone, which is one of the fastest faults in the world, extends along all North Anatolia from Bingöl to Saros Gulf. Several destructive earthquakes occurred there, such as Izmit (in 1999, Mw=7.4) and Duzce (in 1999, Mw=7.2) in last century. The NAFZ is dividing into southern and northern branches to the east of Marmara region and the Northern branch (Main Marmara Fault-MMF) is crossing the Marmara Sea, starting in from the Gulf of Izmit - Adapazarı and reaching the Gulf of Saros. According to recent studies, the MMF is the largest unbroken part of the fault and is divided into segments (among which the Central Marmara-CM and Prince's Island-PI segments). The determination of the deformation accumulated on the MMF has become extremely important especially after the 1999 Izmit earthquake. Recent studies have demonstrated that the Prince's Island segment is fully locked. However, studies that are focused on the Central Marmara segment, that is located offshore Istanbul, a giant metropole that has more than 14 million population, do not conclude about the presence of a seismic gap, capable of generating a big earthquake. Therefore, in the scope of this study, a new GPS network will be established at short and long distance from the Main Marmara Fault, to densify the existing GPS network. several campaign measurements will be necessary to compute a velocity field. The velocity field will reveal the compression and variations of accumulation rate on the fault. Also, the amount of aseismic creep deep within the fault will be determined using Elastic Displacement Modeling method, allowing to conclude about the existence of a seismic gap on the Main Marmara Fault originated from aseismic deformation or not.

Effects of NaBF4 + NaF on the Tensile and Impact Properties of Al-Si-Mg-Fe Alloys

NASA Astrophysics Data System (ADS)

Chen, Zongning; Wang, Tongmin; Zhao, Yufei; Zheng, Yuanping; Kang, Huijun

2015-05-01

NaBF4 + NaF were found to play three roles, i.e., Fe-eliminator, grain refiner, and eutectic modifier, in treating A356 alloy with a high Fe content. The joint effects led to significant improvement in both tensile and impact properties of thus treated alloy. The multiple reactions between the NaBF4 + NaF and Al-Si-Mg-Fe system are suggested to form Fe2B, AlB2, and Na in the melt, as per thermodynamic analysis. The three are responsible for Fe removal, grain refinement, and eutectic modification, respectively. When NaBF4 and NaF are mixed in weight ratio of 1:1, an optimum addition rate is in the range between 1.0 and 2.0 wt pct for treating AlSi7Mg0.3Fe0.65 alloy, based on the results of tensile and impact tests. Excessive addition of the salt may deteriorate the mechanical properties of the alloy, basically owing to overmodification of Si and contamination of salt inclusions.

Fluoride loaded polymeric nanoparticles for dental delivery.

PubMed

Nguyen, Sanko; Escudero, Carlos; Sediqi, Nadia; Smistad, Gro; Hiorth, Marianne

2017-06-15

The overall aim of the present paper was to develop fluoride loaded nanoparticles based on the biopolymers chitosan, pectin, and alginate, for use in dental delivery. First, the preparation of nanoparticles in the presence of sodium fluoride (NaF) as the active ingredient by ionic gelation was investigated followed by an evaluation of their drug entrapment and release properties. Chitosan formed stable, spherical, and monodisperse nanoparticles in the presence of NaF and tripolyphoshate as the crosslinker, whereas alginate and pectin were not able to form any definite nanostructures in similar conditions. The fluoride loading capacity was found to be 33-113ppm, and the entrapment efficiency 3.6-6.2% for chitosan nanoparticles prepared in 0.2-0.4% (w/w) NaF, respectively. A steady increase in the fluoride release was observed for chitosan nanoparticles prepared in 0.2% NaF both in pH5 and 7 until it reached a maximum at time point 4h and maintained at this level for at least 24h. Similar profiles were observed for formulations prepared in 0.4% NaF; however the fluoride was released at a higher level at pH5. The low concentration, but continuous delivery of fluoride from the chitosan nanoparticles, with possible expedited release in acidic environment, makes these formulations highly promising as dental delivery systems in the protection against caries development. Copyright © 2017 Elsevier B.V. All rights reserved.

Circulating testosterone and prostate-specific antigen in nipple aspirate fluid and tissue are associated with breast cancer.

PubMed Central

Sauter, Edward R; Tichansky, David S; Chervoneva, Inna; Diamandis, Eleftherios P

2002-01-01

Preliminary evidence has associated testosterone and prostate-specific antigen (PSA) with breast cancer. Our objective was to determine whether a) testosterone levels in nipple aspirate fluid (NAF), serum, or breast tissue are associated with breast cancer; b) testosterone levels in serum are associated with levels in NAF; c) PSA in NAF, serum, or breast tissue is associated with breast cancer; and d) serum PSA is associated with NAF PSA levels. We obtained 342 NAF specimens from 171 women by means of a modified breast pump. Additionally, we collected 201 blood samples from 99 women and 51 tissue samples from 41 subjects who underwent surgical resection for suspected disease. Women currently using birth control pills or hormone replacement therapy were excluded from the study. Controlling for age and menopausal status, serum testosterone was significantly increased in women with breast cancer (p = 0.002). NAF and serum testosterone levels were not associated. Neither NAF nor tissue testosterone was associated with breast cancer. Controlling for menopausal status and age, NAF PSA was significantly decreased in women with breast cancer (p < 0.001). We did not find serum PSA to be associated with breast cancer, although we found an indication that, in postmenopausal women, its levels were lower in women with cancer. Serum PSA was associated with NAF PSA in postmenopausal women (p < 0.001). PSA levels in cancerous tissue were significantly lower than in benign breast specimens from subjects without cancer (p = 0.011), whereas levels of PSA in histologically benign specimens from subjects with cancer were intermediate. Our results suggest that serum testosterone is increased and NAF PSA is decreased in women with breast cancer, with PSA expression being higher in normal than in cancerous breast tissues. NAF and serum PSA levels in postmenopausal women are correlated, suggesting that as laboratory assessment of PSA becomes more sensitive, serum PSA may become useful in identifying women with breast cancer. PMID:11882474

Quantification of Fluvial Response to Tectonic Deformation and Climate in the Central Pontides, Turkey; Inferences from OSL Dating of Fluvial Terraces

NASA Astrophysics Data System (ADS)

McClain, K.; Yildirim, C.; Çiner, A.; Sahin, S.; Sarıkaya, A.; Ozturk, T.; Kıyak, N. G.; Ozcan, O.

2016-12-01

This study intends to improve the understanding of the topographic evolution and fluvial processes responding to tectonics and climate within the high-relief and deeply-incised Karabük Range of the Central Pontides, a large transpressional wedge at the northern margin of the Central Anatolian Plateau. Insight into these interactions can be obtained through the dating of fluvial sediment and understanding of geomorphic features. From Late Miocene to present, Anatolia's rapid counterclockwise movement, which increases in velocity towards the Hellenic Arc, has formed the North Anatolian Fault (NAF), a dextral transform fault along the Anatolia-Eurasia boundary. North of the transpressional zone of the NAF's massive restraining bend, an area that had experienced previous uplift due to the closure of the Intra-Pontide Ocean, the landscape experienced further uplift and the development of a detached flower structure. In the west side of this zone of transpression, the Filyos River deeply incises a gorge while bisecting the Karabük Range. This created an area with an abundance of indicators of tectonic deformation to map, such as hanging valleys, wind gaps, bedrock gorges, landslides, steep v-shaped channels, as well as an abundance of fluvial strath terraces. In particular, the village of Bolkuş lies among strath terraces of at least 8 ages within just 1.5 km of horizontal distance. In Bolkuş, we used optically stimulated luminescence dating (OSL dating) to estimate five deposition ages of fluvial strath terrace sediment, or their last exposure to daylight, leading to an estimation of incision and uplift rates over time. After collecting three samples from each terrace, with strath elevations of 246, 105.49, 43.6, 15.3 and 3.6 m.a.s.l., we determined corresponding ages of 841 ±76, 681 ±49, 386 ±18, 88 ±5.1 and 50.9 ±2.8 ka. These ages are older than expected for an area of active vertical deformation. Incision rates over time (highest/oldest terrace to lowest/youngest) suggest uplift of 0.29, 0.15, 0.12, 0.17 and 0.07 mm/y. When compared to the mean 0.06 mm/y uplift rate of the Central Anatolian Plateau, the results suggest not only that uplift has slowed, but that the restraining bend transpression of the NAF may no longer cause vertical deformation at this location within the Central Pontides.

A comparative evaluation to assess the efficacy of 5% sodium fluoride varnish and diode laser and their combined application in the treatment of dentin hypersensitivity

PubMed Central

Suri, Isha; Singh, Poonam; Shakir, Quaid Johar; Shetty, Arvind; Bapat, Ranjeet; Thakur, Roshani

2016-01-01

Background: Dentin hypersensitivity (DH) is an age old complaint with a great number of treatment modalities, but none of these are totally effective till date. Lasers being one of the latest treatment options in periodontics, a study was conducted to test the efficacy of diode laser (DL) in DH alone and in comparison with 5% sodium fluoride (NaF) varnish. Aim: The aim of the present study was to compare the effectiveness of 5% topical NaF varnish and 980 nm gallium aluminum arsenide (GaAlAs) DL alone and combination of 5% NaF + 980 nm GaAlAs DL in the management of DH. Materials and Methods: The study was conducted on 120 teeth in thirty patients with DH assessed by tactile and air blast (AB) stimuli measured by visual analog scale (VAS). Teeth were randomly divided into Group 1 (P) placebo-treated control group, Group 2 (NaF) treated by 5% NaF varnish, Group 3 (DL) treated with 980 nm DL, and Group 4 (NaF + DL) treated with both 5% NaF varnish and 980 nm DL (combination group). Results: There was a significant reduction in DH. The VAS reduction percentages were calculated, and there was a significant decrease in DH above all in G4 (NaF + DL) than G3 (DL) and G2 (NaF). Conclusion: Even though all the three groups (2, 3, and 4) showed improvement in terms of DH reduction, 5% NaF varnish with DL showed the best results among all the groups. PMID:27563205

Interactions between mitoNEET and NAF-1 in cells

PubMed Central

Tamir, Sagi; Luo, Yuting; Bai, Fang; Adenwalla, Ammar; Darash-Yahana, Merav; Sohn, Yang-Sung; Jennings, Patricia A.; Azad, Rajeev K.; Onuchic, Jose' N.; Morcos, Faruck; Nechushtai, Rachel

2017-01-01

The NEET proteins mitoNEET (mNT) and nutrient-deprivation autophagy factor-1 (NAF-1) are required for cancer cell proliferation and resistance to oxidative stress. NAF-1 and mNT are also implicated in a number of other human pathologies including diabetes, neurodegeneration and cardiovascular disease, as well as in development, differentiation and aging. Previous studies suggested that mNT and NAF-1 could function in the same pathway in mammalian cells, preventing the over-accumulation of iron and reactive oxygen species (ROS) in mitochondria. Nevertheless, it is unknown whether these two proteins directly interact in cells, and how they mediate their function. Here we demonstrate, using yeast two-hybrid, in vivo bimolecular fluorescence complementation (BiFC), direct coupling analysis (DCA), RNA-sequencing, ROS and iron imaging, and single and double shRNA lines with suppressed mNT, NAF-1 and mNT/NAF-1 expression, that mNT and NAF-1 directly interact in mammalian cells and could function in the same cellular pathway. We further show using an in vitro cluster transfer assay that mNT can transfer its clusters to NAF-1. Our study highlights the possibility that mNT and NAF-1 function as part of an iron-sulfur (2Fe-2S) cluster relay to maintain the levels of iron and Fe-S clusters under control in the mitochondria of mammalian cells, thereby preventing the activation of apoptosis and/or autophagy and supporting cellular proliferation. PMID:28426722

ANTICARIOGENIC POTENCIAL OF ACIDULATE SOLUTIONS WITH LOW FLUORIDE CONCENTRATION

PubMed Central

Delbem, Alberto Carlos Botazzo; Tiano, Gilberto Carlos; Alves, Karina Mirela Ribeiro Pinto; Cunha, Robson Frederico

2006-01-01

Objectives: The aim of this study was to verify the anticariogenic effect of acidulate solutions with low NaF concentration, using pH-cycling model and bovine enamel. Material and methods: Enamel blocks were submitted to the surface microhardness (SMH) test and randomly divided in 12 experimental and one placebo groups. The blocks were submitted to pH cycling for 7 days, with daily applications once/day of 0.05% NaF and 0.1% NaF and twice/day of 0.02% NaF solutions. Four different pH: 4.0, 5.0, 6.0 and 7.0 were used. Next, SMH test was again used to determine the surface microhardness percentage change (%SMH). Data obtained for %SMH were homogeneous and passed through variance analyses and Tukey's test (5%) as far as fluoride concentrations and pH. Results: The results showed that pH influenced %SMH in 0.02% NaF and 0.05% NaF solutions with pH 4.0, which had less mineral loss compared to pH 7.0 (p<0.05). The 0.02% NaF - pH 4.0, and 0.05% NaF – pH 7.0 groups showed similar results (p>0.05). A dose-response relationship was observed among the tested solutions, with better anticariogenic effect for the 0.1% NaF solution. Conclusion: The results suggest that the addition of citric acid to acidulate mouth rinses reduce mineral loss. PMID:19089268

Stretching Fibroblasts Remodels Fibronectin and Alters Cancer Cell Migration

NASA Astrophysics Data System (ADS)

Ao, Mingfang; Brewer, Bryson M.; Yang, Lijie; Franco Coronel, Omar E.; Hayward, Simon W.; Webb, Donna J.; Li, Deyu

2015-02-01

Most investigations of cancer-stroma interactions have focused on biochemical signaling effects, with much less attention being paid to biophysical factors. In this study, we investigated the role of mechanical stimuli on human prostatic fibroblasts using a microfluidic platform that was adapted for our experiments and further developed for both repeatable performance among multiple assays and for compatibility with high-resolution confocal microscopy. Results show that mechanical stretching of normal tissue-associated fibroblasts (NAFs) alters the structure of secreted fibronectin. Specifically, unstretched NAFs deposit and assemble fibronectin in a random, mesh-like arrangement, while stretched NAFs produce matrix with a more organized, linearly aligned structure. Moreover, the stretched NAFs exhibited an enhanced capability for directing co-cultured cancer cell migration in a persistent manner. Furthermore, we show that stretching NAFs triggers complex biochemical signaling events through the observation of increased expression of platelet derived growth factor receptor α (PDGFRα). A comparison of these behaviors with those of cancer-associated fibroblasts (CAFs) indicates that the observed phenotypes of stretched NAFs are similar to those associated with CAFs, suggesting that mechanical stress is a critical factor in NAF activation and CAF genesis.

Seismic Evidence And Complex Trace Attributes Of Shallow Gas Structures In The Sea Of Marmara

NASA Astrophysics Data System (ADS)

Aydemir, Seval; Okay, Seda; Cifci, Gunay; Dondurur, Derman; Sorlien, Christopher; Cormier, Marie-Helene

2015-04-01

Analysis of multi-channel seismic reflection, sparker and chirp data from Marmara Sea observed various shallow gas indicators including seismic chimneys, bright spots, mud diapirs, pockmarks, and acoustic blanking related to gas accumulations along North Anatolian Fault (NAF) system which branches out towards the west into the in Marmara Sea. Middle branch of the (NAF) is the place where distinct amount of seismic activity has occurred and gas deposits have been observed. This study is also devoted to evaluate the gas related structures with seismic attributes of multichannel seismic reflection data which have been collected at South Marmara shelf. The dataset was collected in September 2013 and July 2014 including nearly 1000 km high Resolution Multichannel Seismic and Chirp data and 967 km Sparker data in the frame of a bilateral TÜBİTAK Project onboard R/V K. Piri Reis. The streamer has 168 or 144 channel and group interval was 6.25 m. The source was 45+45 inch GI gun fired every 12.5 or 25 m producing high-resolution seismic signal between 10-250 Hz frequency bands. The Chirp data was collected with a transducer, which produced acoustic signal between 2.75-6.75 kHz. The source of sparker system was used to 1000 J. The data have been processed using a conventional data processing flow. In addition attributes were applied to final migration sections and than was tried to find gas accumulations with Reflection strength section, instantaneous frequency section and apparent polarity. Reflection strength section has strong reflections (bright spot). Also instantaneous frequency section has low-frequency zone depending on absorption where gas accumulations are expected. Apparent polarity section has negative polarity anamoly due to low acoustic impedance where gas accumulations are expected in sediments. In addition, attributes were coincided with sparker and chirp data where expected shallow gas accumulations.

Exposure to Sodium Fluoride Produces Signs of Apoptosis in Rat Leukocytes

PubMed Central

Gutiérrez-Salinas, José; Morales-González, José A.; Madrigal-Santillán, Eduardo; Esquivel-Soto, Jaime; Esquivel-Chirino, César; González-Rubio, Manuel García-Luna y; Suástegui-Domínguez, Sigrit; Valadez-Vega, Carmen

2010-01-01

Fluoride is naturally present in the earth’s crust and can be found in rocks, coal, and clay; thus, it can be found in small quantities in water, air, plants, and animals. Therefore, humans are exposed to fluoride through food, drinking water, and in the air they breathe. Flouride is essential to maintain bone strength and to protect against dental decay, but if it is absorbed too frequently, it can cause tooth decay, osteoporosis, and damage to kidneys, bones, nerves, and muscles. Therefore, the present work was aimed at determining the effect of intake of sodium fluoride (NaF) as an apoptosis inducer in leukocytes of rats treated for eight weeks with 1 or 50 parts per million (ppm) NaF. Expression of p53, bcl-2, and caspade-3 were used as apoptotic and general metabolism indicators of leukocyte-like indicators of the (INT) oxidation system. Male rats were exposed to NaF (1 and 500 ppm) for eight weeks, and then sacrificed weekly to obtain blood samples. Expression of p53, bcl-2, and caspase-3 were determined in leukocytes by Western blot, and general metabolism of leukocytes was analyzed with a commercial kit. We found changes in the expression of the proteins described, especially when the animals received 50 ppm of NaF. These results indicate that NaF intoxication can be an apoptosis inducer in rat leukocytes treated with the compound for eight weeks. PMID:20957113

The model of nano-scale copper particle removal from silicon surface in high pressure CO2 + H2O and CO2 + H2O + IPA cleaning solutions.

PubMed

Tan, Xin; Chai, Jiajue; Zhang, Xiaogang; Chen, Jiawei

2011-12-01

This study focuses on the description of the static forces in CO2-H2O and CO2-H2O-IPA cleaning solutions with a separate fluid phase entrapped between nano-scale copper particles and a silicon surface. Calculations demonstrate that increasing the pressure of the cleaning system decreases net adhesion force (NAF) between the particle and silicon. The NAF of a particle for in CO2-H2O-IPA system is less than that in CO2-H2O system, suggesting that the particles enter into bulk layer more easily as the CO2-H2O cleaning system is added IPA.

Characterization of the microbiome of nipple aspirate fluid of breast cancer survivors.

PubMed

Chan, Alfred A; Bashir, Mina; Rivas, Magali N; Duvall, Karen; Sieling, Peter A; Pieber, Thomas R; Vaishampayan, Parag A; Love, Susan M; Lee, Delphine J

2016-06-21

The microbiome impacts human health and disease. Until recently, human breast tissue and milk were presumed to be sterile. Here, we investigated the presence of microbes in the nipple aspirate fluid (NAF) and their potential association with breast cancer. We compared the NAF microbiome between women with a history of breast cancer (BC) and healthy control women (HC) using 16S rRNA gene amplicon sequencing. The NAF microbiome from BC and HC showed significant differences in community composition. Two Operational Taxonomic Units (OTUs) showed differences in relative abundances between NAF collected from BC and HC. In NAF collected from BC, there was relatively higher incidence of the genus Alistipes. By contrast, an unclassified genus from the Sphingomonadaceae family was relatively more abundant in NAF from HC. These findings reflect the ductal source DNA since there were no differences between areolar skin samples collected from BC and HC. Furthermore, the microbes associated with BC share an enzymatic activity, Beta-Glucuronidase, which may promote breast cancer. This is the first report of bacterial DNA in human breast ductal fluid and the differences between NAF from HC and BC. Further investigation of the ductal microbiome and its potential role in breast cancer are warranted.

F-18 sodium fluoride PET/CT does not effectively image myocardial inflammation due to suspected cardiac sarcoidosis.

PubMed

Weinberg, Richard L; Morgenstern, Rachelle; DeLuca, Albert; Chen, Jennifer; Bokhari, Sabahat

2017-12-01

Sarcoidosis is an inflammatory disorder of unknown etiology that can involve the heart. While effective in imaging cardiac sarcoidosis, F-18 fluorodeoxyglucose (FDG) PET/CT often shows non-specific myocardial uptake. F-18 sodium fluoride (NaF) has been used to image inflammation in coronary artery plaques and has low background myocardial uptake. Here, we evaluated whether F-18 NaF can image myocardial inflammation due to clinically suspected cardiac sarcoidosis. We performed a single institution pilot study testing if F-18 NaF PET/CT can detect myocardial inflammation in patients with suspected cardiac sarcoidosis. Patients underwent cardiac PET/CT with F-18 FDG as part of their routine care and subsequently received an F-18 NaF PET/CT scan. Three patients underwent F-18 FDG and F-18 NaF imaging. In all patients, there was F-18 FDG uptake consistent with cardiac sarcoidosis. The F-18 NaF PET/CT scans showed no myocardial uptake. In this small preliminary study, PET/CT scan using F-18 NaF does not appear to detect myocardial inflammation caused by suspected cardiac sarcoidosis.

Comparison of NaF and FDG PET/CT for assessment of treatment response in castrate-resistant prostate cancers with osseous metastases

PubMed Central

Simoncic, Urban; Perlman, Scott; Liu, Glenn; Staab, Mary Jane; Straus, Jane; Jeraj, Robert

2014-01-01

Background Assessment of skeletal metastases response to therapy is highly relevant, but unresolved clinical problem. The main goal of this work was to compare pharmacodynamic responses to therapy assessed with NaF and FDG PET/CT. Materials and Methods Prostate cancer patients with known osseous metastases were treated with Zibotentan (ZD4054) and imaged with combined dynamic NaF/FDG PET/CT prior to therapy (Baseline), after 4 weeks of therapy (Week 4) and after 2 weeks of treatment break (Week 6). Kinetic analysis allowed comparison of voxel-based tracer uptake rate parameter Ki, vasculature parameters K1 (measuring perfusion/permeability) and Vb (measuring vasculature fraction in the tissue) together with standardized uptake values (SUVs). Results Correlations were high for the NaF and FDG peak uptake parameters (Ki and SUV correlations ranged from 0.57 to 0.88) and for vasculature parameters (K1 and Vb correlations ranged from 0.61 to 0.81). Correlation between the NaF and FDG Week 4 Ki responses was low (ρ=0.35, p=0.084), but higher for NaF and FDG Week 6 Ki responses (ρ=0.72, p<0.0001). Correlations for vasculature responses were always low (ρ<0.35). NaF and FDG uptakes in the osseous metastases were spatially dislocated, with overlap in the range from 0% to 80%. Conclusions These results showed that late NaF and FDG uptake responses are consistently correlated, but earlier uptake responses and all vasculature responses can be unrelated. This study also proved that FDG and NaF uptakes are spatially dislocated. Although treatment responses assessed with NaF and FDG may be correlated, using both tracers provides additional information. PMID:25128349

Effect of fluoride sodium mouthwash solutions on cpTI: evaluation of physicochemical properties.

PubMed

Toniollo, Marcelo Bighetti; Galo, Rodrigo; Macedo, Ana Paula; Rodrigues, Renata Cristina Silveira; Ribeiro, Ricardo Faria; Mattos, Maria da Gloria Chiarello de

2012-01-01

The effects of fluoride, which is present in different oral hygiene products, deserve more investigation because little is known about their impact on the surface of titanium, which is largely used in Implantology. This study evaluated the surface of commercially pure titanium (cpTi) after exposure to different concentrations of sodium fluoride (NaF). The hypothesis tested in this study was that different concentrations of NaF applied at different time intervals can affect the titanium surface in different ways. The treatments resulted in the following groups: GA (control): immersion in distilled water; GB: immersion in 0.05% NaF for 3 min daily; GC: immersion in 0.2% NaF for 3 min daily; GD: immersion in 0.05% NaF for 3 min every 2 weeks; and GE: immersion in 0.2% NaF for 3 min every 2 weeks. The experiment lasted 60 days. Roughness was measured initially and every 15 days subsequently up to 60 days. After 60 days, corrosion analysis and anodic polarization were done. The samples were examined by scanning electron microscopy (SEM). The roughness data were analyzed by ANOVA and there was no significant difference among groups and among time intervals. The corrosion data (i(corr)) were analyzed by the Mann-Whitney test, and significant differences were found between GA and GC, GB and GC, GC and GD, GC and GE. SEM micrographs showed that the titanium surface exposed to NaF presented corrosion that varied with the different concentrations. This study suggests that the use of 0.05% NaF solution on cpTi is safe, whereas the 0.2% NaF solution should be carefully evaluated with regard to its daily use.

Influence of Surfactants and Fluoride against Enamel Erosion.

PubMed

Zanatta, Rayssa Ferreira; Ávila, Daniele Mara da Silva; Miyamoto, Karen Mayumi; Torres, Carlos Rocha Gomes; Borges, Alessandra Bühler

2018-06-06

This study investigated the effect of surfactants associated with sodium fluoride (NaF) on enamel erosion prevention, using an erosion-remineralization in vitro model. Sodium lauryl sulfate (SLS), polysorbate 20 (P20), and cocoamidopropyl betaine (CAPB) were tested, at concentrations of 1.0 and 1.5%, and associated or not with NaF (275 ppm). The control groups were distilled water and the NaF solution. Bovine enamel samples (n = 12) were prepared and submitted to a 5-day cycling model: acid challenge (0.3% citric acid, pH 2.6, 4×/day), human saliva (2 h, 4×/day), and the treatment solutions (2 min, 2×/day). The protective potential of the agents against initial erosion was assessed by microhardness and the surface loss by profilometry. Enamel surface wettability was determined by goniometry, protein adsorption was measured by spectroscopy (FTIR), and the KOH-soluble fluoride was quantified. Goniometry showed that SLS and CAPB increased enamel wettability. No differences were found among the surfactants regarding protein adsorption. Microhardness showed that SLS reduced NaF protection. P20 (1 and 1.5%) and CAPB 1.5% presented a protective effect, but lower than the NaF solution. Profilometry showed that CAPB protected enamel, but no agent associated with NaF promoted a higher protection than the NaF solution alone. KOH-soluble fluoride analysis showed that all surfactants reduced the fluoride adsorption on the enamel surface. Therefore, the surfactants tested (except for P20) changed the enamel surface energy. The SLS decreased the protective potential of NaF on initial erosion, but no tested agent interfered with the protective effect of NaF on enamel erosive wear. © 2018 S. Karger AG, Basel.

Erosion protection by calcium lactate/sodium fluoride rinses under different salivary flows in vitro.

PubMed

Borges, Alessandra B; Scaramucci, Taís; Lippert, Frank; Zero, Domenick T; Hara, Anderson T

2014-01-01

This study investigated the effect of a calcium lactate prerinse on sodium fluoride protection in an in vitro erosion-remineralization model simulating two different salivary flow rates. Enamel and dentin specimens were randomly assigned to 6 groups (n = 8), according to the combination between rinse treatments - deionized water (DIW), 12 mM NaF (NaF) or 150 mM calcium lactate followed by NaF (CaL + NaF) - and unstimulated salivary flow rates - 0.5 or 0.05 ml/min - simulating normal and low salivary flow rates, respectively. The specimens were placed into custom-made devices, creating a sealed chamber on the specimen surface connected to a peristaltic pump. Citric acid was injected into the chamber for 2 min, followed by artificial saliva (0.5 or 0.05 ml/min) for 60 min. This cycle was repeated 4×/day for 3 days. Rinse treatments were performed daily 30 min after the 1st and 4th erosive challenges, for 1 min each time. Surface loss was determined by optical profilometry. KOH-soluble fluoride and structurally bound fluoride were determined in specimens at the end of the experiment. Data were analyzed by 2-way ANOVA and Tukey tests (α = 0.05). NaF and CaL + NaF exhibited significantly lower enamel and dentin loss than DIW, with no difference between them for normal flow conditions. The low salivary flow rate increased enamel and dentin loss, except for CaL + NaF, which presented overall higher KOH-soluble and structurally bound fluoride levels. The results suggest that the NaF rinse was able to reduce erosion progression. Although the CaL prerinse considerably increased F availability, it enhanced NaF protection against dentin erosion only under hyposalivatory conditions.

Subsurface signature of North Anatolian Fault Zone and its relation with old sutures: New insight from receiver function analysis.

NASA Astrophysics Data System (ADS)

Özacar, Arda A.; Abgarmi, Bizhan

2017-04-01

The North Anatolian Fault Zone (NAFZ) is an active continental transform plate boundary that accommodates the westward extrusion of the Anatolian plate. The central segment of NAFZ displays northward convex surface trace which coincides partly with the Paleo-Tethyan suture formed during the early Cenozoic. The depth extent and detailed structure of the actively deforming crust along the NAF is still under much debate and processes responsible from rapid uplift are enigmatic. In this study, over five thousand high quality P receiver functions are computed using teleseismic earthquakes recorded by permanent stations of national agencies and temporary North Anatolian Fault Passive Seismic experiment (2005-2008). In order to map the crustal thickness and Vp/Vs variations accurately, the study area is divided into grids with 20 km spacing and along each grid line Moho phase and its multiples are picked through constructed common conversion point (CCP) profiles. According to our results, nature of discontinuities and crustal thickness display sharp changes across the main strand of NAFZ supporting a lithospheric scale faulting that offsets Moho discontinuity. In the southern block, crust is relatively thin in the west ( 35 km) and becomes thicker gradually towards east ( 40 km). In contrast, the northern block displays a strong lateral change in crustal thickness reaching up to 10 km across a narrow roughly N-S oriented zone which is interpreted as the subsurface signature of the ambiguous boundary between Istanbul Block and Pontides located further west at the surface.

[Interaction between fluorine and zinc after long-term oral administration into the digestive system of rats].

PubMed

Mazurek-Mochol, Małgorzata

2002-01-01

Drug interactions are the side effect of administration of two or more drugs or a drug-food combination. Although some drug interactions are intentional and beneficial to the patient, the majority are unintentional and associated with a potentially harmful effect. The aim of this study was to search for interactions in rats between fluoride and zinc administered orally for 12 weeks and to elucidate any potential toxicological and therapeutic consequences. 60 male Wistar rats were divided into six groups of ten rats each and exposed to: 1. controls (distilled water); 2. sodium fluoride (NaF); 3. low-dose zinc (Zn); 4. high-dose zinc; 5. NaF + low-dose Zn; 6. NaF + high-dose Zn. At the end of the experiment the content of F- and Zn+ in serum, urine, incisors, femur and mandible was measured and densitometry of femoral bones was performed. Serum alkaline phosphatase, alanine and aspartate aminotransferase activities, as well as bilirubin and creatinine concentrations were determined to confirm non-toxicity of fluoride dose. Animals receiving NaF only demonstrated higher content of fluorine in serum, urine bones and teeth. Zinc concentrations in serum, urine, bones and teeth were elevated in rats receiving zinc with or without NaF. Fluorine accumulation in bones and teeth was reduced by Zn, but in general the effect lacked statistical significance. Zinc slightly reduced the concentrations of fluorine in serum and urine. Sodium fluoride slightly reduced the concentration of zinc in serum and urine. Bone mineral content (BMC) was significantly increased by NaF and was not further increased by co-administration of zinc. No changes in serum alkaline phosphatase, alanine and aspartate aminotransferase activities, bilirubin and creatinine concentrations were detected. In conclusion, simultaneous administration of fluorine and zinc may be beneficial for prevention and treatment of pathologic conditions in bones and teeth and is not accompanied by an increase in fluorine levels which could be responsible for toxicological symptoms.

High-Dose Fluoride Impairs the Properties of Human Embryonic Stem Cells via JNK Signaling.

PubMed

Fu, Xin; Xie, Fang-Nan; Dong, Ping; Li, Qiu-Chen; Yu, Guang-Yan; Xiao, Ran

2016-01-01

Fluoride is a ubiquitous natural substance that is often used in dental products to prevent dental caries. The biphasic actions of fluoride imply that excessive systemic exposure to fluoride can cause harmful effects on embryonic development in both animal models and humans. However, insufficient information is available on the effects of fluoride on human embryonic stem cells (hESCs), which is a novel in vitro humanized model for analyzing the embryotoxicities of chemical compounds. Therefore, we investigated the effects of sodium fluoride (NaF) on the proliferation, differentiation and viability of H9 hESCs. For the first time, we showed that 1 mM NaF did not significantly affect the proliferation of hESCs but did disturb the gene expression patterns of hESCs during embryoid body (EB) differentiation. Higher doses of NaF (2 mM and above) markedly decreased the viability and proliferation of hESCs. The mode and underlying mechanism of high-dose NaF-induced cell death were further investigated by assessing the sub-cellular morphology, mitochondrial membrane potential (MMP), caspase activities, cellular reactive oxygen species (ROS) levels and activation of mitogen-activated protein kinases (MAPKs). High-dose NaF caused the death of hESCs via apoptosis in a caspase-mediated but ROS-independent pathway, coupled with an increase in the phospho-c-Jun N-terminal kinase (p-JNK) levels. Pretreatment with a p-JNK-specific inhibitor (SP600125) could effectively protect hESCs from NaF-induced cell death in a concentration- and time-dependent manner. These findings suggest that NaF might interfere with early human embryogenesis by disturbing the specification of the three germ layers as well as osteogenic lineage commitment and that high-dose NaF could cause apoptosis through a JNK-dependent pathway in hESCs.

A novel third generation uric acid biosensor using uricase electro-activated with ferrocene on a Nafion coated glassy carbon electrode.

PubMed

Ghosh, Tanushree; Sarkar, Priyabrata; Turner, Anthony P F

2015-04-01

A new uric acid biosensor was constructed using ferrocene (Fc) induced electro-activated uricase (UOx) deposited within Nafion (Naf) on glassy carbon electrode (GCE). Electro-activation of UOx was successfully achieved by cyclic voltammetry through the electrostatic interaction of Fc with Trp residues within the hydrophobic pockets in UOx. The Naf/UOx/Fc composite was characterised by AFM, FTIR and EDX to ensure proper immobilisation. The interaction of Fc with the enzyme was analysed by Trp fluorescence spectroscopy and the α-helicity of the protein was measured by CD spectropolarimetry. The charge transfer resistance (Rct), calculated from electrochemical impedance spectroscopy, for the modified sensor was lowered (1.39 kΩ) and the enzyme efficiency was enhanced by more than two fold as a result of Fc incorporation. Cyclic voltammetry, differential pulse voltammetry and amperometry all demonstrated the excellent response of the Naf/UOx/Fc/GCE biosensor to uric acid. The sensor system generated a linear response over a range of 500 nM to 600 μM UA, with a sensitivity and limit of detection of 1.78 μA μM(-1) and 230 nM, respectively. The heterogeneous rate constant (ks) for UA oxidation was much higher for Naf/UOx/Fc/GCE (1.0 × 10(-4) cm s(-1)) than for Naf/UOx/GCE (8.2 × 10(-5) cm s(-1)). Real samples, i.e. human blood, were tested for serum UA and the sensor yielded accurate results at a 95% confidence limit. Copyright © 2014 Elsevier B.V. All rights reserved.

Characterization of the microbiome of nipple aspirate fluid of breast cancer survivors

PubMed Central

Chan, Alfred A.; Bashir, Mina; Rivas, Magali N.; Duvall, Karen; Sieling, Peter A.; Pieber, Thomas R.; Vaishampayan, Parag A.; Love, Susan M.; Lee, Delphine J.

2016-01-01

The microbiome impacts human health and disease. Until recently, human breast tissue and milk were presumed to be sterile. Here, we investigated the presence of microbes in the nipple aspirate fluid (NAF) and their potential association with breast cancer. We compared the NAF microbiome between women with a history of breast cancer (BC) and healthy control women (HC) using 16S rRNA gene amplicon sequencing. The NAF microbiome from BC and HC showed significant differences in community composition. Two Operational Taxonomic Units (OTUs) showed differences in relative abundances between NAF collected from BC and HC. In NAF collected from BC, there was relatively higher incidence of the genus Alistipes. By contrast, an unclassified genus from the Sphingomonadaceae family was relatively more abundant in NAF from HC. These findings reflect the ductal source DNA since there were no differences between areolar skin samples collected from BC and HC. Furthermore, the microbes associated with BC share an enzymatic activity, Beta-Glucuronidase, which may promote breast cancer. This is the first report of bacterial DNA in human breast ductal fluid and the differences between NAF from HC and BC. Further investigation of the ductal microbiome and its potential role in breast cancer are warranted. PMID:27324944

Aseismic slip and surface creep on the Hazar-Palu Section of the East Anatolian Fault, Turkey

NASA Astrophysics Data System (ADS)

Ergintav, S.; Cakir, Z.; Dogan, U.; Cetin, S.; Senturk, S.; Karabulut, H.; Saroglu, F.; Dikmen, U.; Bilham, R. G.; Ozdemir, A.; Julaiti, W.; Ozener, H.

2017-12-01

Forming the boundary between the Anatolian and Arabian plates in Turkey, the East Anatolian fault (EAF) is one of the most important tectonic structures in the Eastern Mediterranean region. Together with its conjugate, the North Anatolian Fault (NAF), it accommodates the westward motion of the Anatolian plate at a rate of 10 mm/yr. We study the interseismic deformation along the eastern section of the EAF using SAR data (2012-2017). Interferograms are calculated, using GMT5SAR software (Sandwell et al., 2011). The interferograms are then used to map the velocity field with the Stanford Method for Persistent Scatterers technique (STAMPS; Hooper et al., 2012). In 2015 a new GPS network was established with 6 fault perpendicular profiles crossing segments identified to be creeping from SAR analysis. The closest GPS sites are within 2 km from the surface EAF. Far-field continuous GPS sites permit us to determine the long-term slip rate and hence the depth of creep on the fault using dislocation models. Additionally, two creepmeters were installed to monitor fault creep in a railway tunnel crossing the fault at ≈50 m depth below the ruined medieval village of Palu, at a location where the walls of the tunnel have been offset by 10-20 cm since construction in the middle of the last century. To confirm these results, earthquake catalogs were, also, re-analyzed. The preliminary results, which are obtained from multidisciplinary data, confirm the average slip rate of the EAF is about 10 mm/yr. The results also reveal that the 100-km-long Palu segment in the Elazıg-Bingöl seismic gap is exhibiting aseismic creep at the surface. The surface creep rate varies along the fault locally attaining the far field plate velocity (i.e. 10 mm/yr), implying that significant portion of the elastic strain has been released aseismically. Preliminary modelling with elastic dislocations suggests that some sections of the fault may be creeping from the surface down to the entire seismogenic crust. Our data are the first to confirm aseismic slip on the EAF (supported by TUBITAK 1001 project no:114Y250)

Influence of methionine and vitamin E on fluoride concentration in bones and teeth of rats exposed to sodium fluoride in drinking water.

PubMed

Błaszczyk, Iwona; Birkner, Ewa; Gutowska, Izabela; Romuk, Ewa; Chlubek, Dariusz

2012-06-01

Increased exposure to fluorine-containing compounds leads to accumulation of fluorides in hard tissues of bones and teeth, which may result in numerous skeletal and dental disorders. This study evaluates the influence of methionine and vitamin E on fluoride concentration in bones and teeth of rats subjected to long-term exposure to sodium fluoride in drinking water. The study was conducted in 30 3-month-old female Wistar FL rats. The animals were divided into five groups, six rats per group. The control group consisted of rats receiving only distilled water as drinking water. All other groups received NaF in the amount of 10 mg/kg of body mass/day in their drinking water. In addition, respective animal groups received: NaF + Met group--10 mg of methionine/kg of body mass/day, NaF + Met + E group--10 mg of methionine/kg of body mass/day and 3 mg of vitamin E (tocopheroli acetas)/rat/day and NaF + E group--3 mg of vitamin E/rat/day. Femoral bones and incisor teeth were collected for the study, and the fluoride concentration was determined using a fluoride ion-selective electrode. Fluoride concentration in both bones and teeth was found to be higher in the NaF and NaF + Met groups compared to the control group. In groups NaF + Met + E and NaF + E, the study material contained much lower fluoride concentration compared to the NaF group, while the effect was more prominent in the NaF + E group. The results of the studies indicate that methionine and vitamin E have opposite effects on accumulation of fluorides in hard tissue in rats. By stimulating fluoride accumulation, methionine reduces the adverse effect of fluorides on soft tissue, while vitamin E, which prevents excessive accumulation of fluorides in bones and teeth, protects these tissues from fluorosis. Therefore, it seems that combined application of both compounds would be optimal for the prevention of the adverse effects of chronic fluoride intoxication.

Specific binding, internalization, and degradation of human neutrophil activating factor by human polymorphonuclear leukocytes

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

Besemer, J.; Hujber, A.; Kuhn, B.

1989-10-15

The interaction of {sup 125}I-labeled recombinant human neutrophil activating factor (NAF) with polymorphonuclear leukocytes (PMN) was studied by means of a radioreceptor assay. The binding was characterized by a rapid transition (t1/2 less than or equal to 1 min) from a pH 3-sensitive state at 4{degree}C to pH 3 resistance at 37{degree}C. This was not caused by internalization of NAF since pH 3-resistant bound iodinated NAF could still be exchanged by an excess of nonlabeled NAF, i.e. was dissociable. Internalized iodinated NAF was processed into trichloroacetic acid-soluble forms. Scatchard transformation of binding isotherms at 4 and 37{degree}C led to nonlinearmore » curves, a finding which is consistent with the expression of two receptor populations, one with high (KD = 11-35 pM) and the other with lower affinity (KD = 640-830 pM) at 4 degrees C. Numbers of the low affinity binding sites were approximately 34,000, and those with high affinity were 5,200/PMN when estimated at 4 degrees C. Binding of iodinated NAF to PMN was specific since it could be competed by an excess of nonlabeled NAF but not by two other activators of PMN function, formylmethionyl-leucyl-phenylalanine or human recombinant granulocyte-macrophage colony-stimulating factor. In addition to human PMN, NAF also bound specifically to two human monocytic cell lines; however, only the low affinity binding site could be detected on these cells.« less

Evaluation of standardized Bacopa monniera extract in sodium fluoride-induced behavioural, biochemical, and histopathological alterations in mice.

PubMed

Balaji, Bhaskar; Kumar, Ekambaram Prem; Kumar, Anil

2015-01-01

Effect of standardized Bacopa monniera (BM; family: Scrophulariaceae) extract (100 and 300 mg/kg) against sodium fluoride (NaF; 100 and 200 ppm)-induced behavioural, biochemical, and neuropathological alterations in mice was evaluated. Akinesia, rotarod (motor coordination), forced swim test (depression), open field test (anxiety), transfer latency (memory), cholinesterase (ChE), and oxidative stress (superoxide dismutase, catalase, glutathione peroxidase, and lipid peroxidation) were determined in mice treated with NaF for 30 days alone and in combination with BM. NaF induced motor incoordination, depression, and memory impairment, and these were prevented by coadministration of BM in mice. However, NaF did not alter the weight gain, feed/water consumption, and anxiety profile. Suppression of ChE levels and increased oxidative stress were observed in mice treated with NaF. Coadministration of BM significantly improved the memory, ChE levels, and antioxidant enzymes but failed to alter the fluoride levels in NaF-treated mice. Histopathological studies revealed that BM protected the neuropathological alterations induced by NaF. © The Author(s) 2012.

Comparison of NaF and FDG PET/CT for assessment of treatment response in castration-resistant prostate cancers with osseous metastases.

PubMed

Simoncic, Urban; Perlman, Scott; Liu, Glenn; Staab, Mary Jane; Straus, Jane Elizabeth; Jeraj, Robert

2015-02-01

Assessment of skeletal metastases' response to therapy is a highly relevant but unresolved clinical problem. The main goal of this work was to compare pharmacodynamic responses to therapy assessed with positron emission tomography-computed tomography (PET/CT) using fluorine-18 sodium fluoride (NaF) and fluorine-18 fluorodeoxyglucose (FDG) as the tracers. Patients with prostate cancer with known osseous metastases were treated with zibotentan (ZD4054) and imaged with combined dynamic NaF/FDG PET/CT before therapy (baseline), after 4 weeks of therapy (week 4), and after 2 weeks of treatment break (week 6). Kinetic analysis allowed comparison of the voxel-based tracer uptake rate parameter Ki, the vasculature parameters K1 (measuring perfusion/permeability) and Vb (measuring vasculature fraction in the tissue), and the standardized uptake values (SUVs). Correlations were high for the NaF and FDG peak uptake parameters (Ki and SUV correlations ranged from 0.57 to 0.88) and for vasculature parameters (K1 and Vb correlations ranged from 0.61 to 0.81). Correlation was low between the NaF and FDG week 4 Ki responses (ρ = 0.35; P = .084) but was higher for NaF and FDG week 6 Ki responses (ρ = 0.72; P < .0001). Correlations for vasculature responses were always low (ρ < 0.35). NaF and FDG uptakes in the osseous metastases were spatially dislocated, with overlap in the range from 0% to 80%. This study found that late NaF and FDG uptake responses are consistently correlated but that earlier uptake responses and all vasculature responses can be unrelated. This study also confirmed that FDG and NaF uptakes are spatially dislocated. Although treatment responses assessed with NaF and FDG may be correlated, using both tracers provides additional information. Copyright © 2015 Elsevier Inc. All rights reserved.

Sodium fluoride induces apoptosis in the kidney of rats through caspase-mediated pathways and DNA damage.

PubMed

Song, Guo Hua; Gao, Ji Ping; Wang, Chun Fang; Chen, Chao Yang; Yan, Xiao Yan; Guo, Min; Wang, Yu; Huang, Fu Bing

2014-09-01

Long-term excessive sodium fluoride (NaF) intake can cause many bone diseases and nonskeletal fluorosis. The kidneys are the primary organs involved in the excretion and retention of NaF. The objective of the present study was to determine the effects of NaF treatment on renal cell apoptosis, DNA damage, and the protein expression levels of cytosolic cytochrome C (Cyt C) and cleaved caspases 9, 8, and 3 in vivo. Male Sprague-Dawley rats were divided randomly into four groups (control, low fluoride, medium fluoride, and high fluoride) and administered 0, 50, 100, and 200 mg/L of NaF, respectively, via drinking water for 120 days. Histopathological changes in the kidneys were visualized using hematoxylin and eosin staining. Renal cell apoptosis was examined using flow cytometry, and renal cell DNA damage was detected using the comet assay. Cytosolic Cyt C and cleaved caspases 9, 8, and 3 protein expression levels were visualized using immunohistochemistry and Western blotting. The results showed that NaF treatment increased apoptosis and DNA damage. In addition, NaF treatment increased the protein expression levels of cytosolic Cyt C and cleaved caspases 9, 8, and 3. These results indicated that NaF induces apoptosis in the kidney of rats through caspase-mediated pathway, and DNA damage may be involved in this process.

Increased caries-incidence by oral inoculation of cariogenic bacteria in rats after dietary fluoride

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

Clark, W.B.; Kreitzman, S.N.; Howell, T.H.

1976-04-01

The authors had previously observed that dietary NaF administered to rats during the formative and eruptive stages of tooth development does not significantly reduce the enamel solubility in acid buffer solution. They hypothesized that NaF reduces the cariogenicity of the bacterial flora. In order to test this hypothesis, rats from the same litter were divided into three groups all of which received a cariogenic diet. Group one received no fluoride. Groups two and three were supplemented with 50 ppm NaF, from day 1 to day 21. In the first study, one of the 21-day-old NaF-supplemented groups was inoculated by smearsmore » of fecal material from the control animals that did not receive NaF supplement. The second NaF group was not inoculated and served as control. In a second study, cariogenic Strep. mutans 6715 was used as the inoculum in place of the fecal smear. In both studies, the inoculation of a NaF group increased the caries to about 70% of the control group, while the mean scores on the non-inoculated NaF group were about 50% of the control group. These results indicate that alteration of the transmissible flora may be an important factor in the cariostatic action of dietary fluoride in experimental animals. This observation supports the suggestion that fluoride may alter the cariogenic flora.« less

Soil fluoride spiking effects on olive trees (Olea europaea L. cv. Chemlali).

PubMed

Zouari, M; Ben Ahmed, C; Fourati, R; Delmail, D; Ben Rouina, B; Labrousse, P; Ben Abdallah, F

2014-10-01

A pot experiment under open air conditions was carried out to investigate the uptake, accumulation and toxicity effects of fluoride in olive trees (Olea europaea L.) grown in a soil spiked with inorganic sodium fluoride (NaF). Six different levels (0, 20, 40, 60, 80 and 100mM NaF) of soil spiking were applied through NaF to irrigation water. At the end of the experiment, total fluoride content in soil was 20 and 1770mgFkg(-1) soil in control and 100mM NaF treatments, respectively. The comparative distribution of fluoride partitioning among the different olive tree parts showed that the roots accumulated the most fluoride and olive fruits were minimally affected by soil NaF spiking as they had the lowest fluoride content. In fact, total fluoride concentration varied between 12 and 1070µgFg(-1) in roots, between 9 and 570µgFg(-1) in shoots, between 12 and 290µgFg(-1) in leaves, and between 10 and 29µgFg(-1) in fruits, respectively for control and 100mM NaF treatments. Indeed, the fluoride accumulation pattern showed the following distribution: roots>shoots>leaves>fruits. On the other hand, fluoride toxicity symptoms such as leaf necrosis and leaf drop appeared only in highly spiked soils (60, 80 and 100mM NaF). Copyright © 2014 Elsevier Inc. All rights reserved.

L band InSAR sudy on the Ganos section of the North Anatolian Fault Zone (NAFZ)

NASA Astrophysics Data System (ADS)

de Michele, Marcello

2016-04-01

The North Anatolian Fault (NAF), with a total length of about 1500 km, is one of the most active right-lateral strike-slip faults in the world. It defines the tectonic boundary between the Anatolian Plate and the Eurasian Plate in northern Turkey, accommodating ~14-30 mm/yr of relative plate motion between the two plates (fig. 1). The Gazikoy-Saros segment (the Ganos fault, GF) is the onshore segment of the northern strand of the NAF between the Marmara Sea and the Gulf of Saros. It was last ruptured in 1912 with a Ms=7.4 earthquake that broke the entire inland segment of the fault, a length of about 50 km, and produced a right-lateral strike-slip component of at least 3 m. Other large historical earthquakes that have been attributed to the Ganos fault occurred in A.D. 824, 1343, 1509 and 1766 (e. g. Reilinger et al., 2000; Meade et al., 2002; Motagh et al., 2007; Janssen et al., 2009; Megraoui et al., 2012 ; Ersen Aksoy et al., 2010). The GF forms a 45 km long linear fault system and represents the link between the northern strand of the NAFZ in the Sea of Marmara and the North Aegean Trough where slip partitioning results in branching of the fault zone. The present study aims at showing the results retrieved from L band Interferometric Syntethic Aperture Radar (InSAR) measurements for the monitoring of Crustal Deformation in the Anatolian Fault Zone in the frame of the MARMARA SUPERSITE PROJECT "MARSITE" on the Ganos section of the North Anatolian fault zone. We processed SAR data made available through the CAT-1 ESA (European Space Agency) archives, acquired by the L-band radar sensor ALOS PALSAR between 2007 and 2011. The aim of this exercise is to test L-band capabilities to map the spatial and temporal evolution of the present-day crustal deformation phenomena affecting the Ganos section of the NAFZ with high level of spatial details. The goal of this task is to assess whether InSAR L-Band data can be useful to evaluate the long-term behavior of active faults and eventual interactions between geologic structures, complementarily to GPS measurements and other in-situ observations on the study area. Mid-term monitoring (4 - 10 years) of the crustal deformation in the MARsite area is targeted. The ALOS Palsar archive over the Ganos Section of the NAFZ is not extraordinarily rich concerning the number of SAR scenes acquired with the same viewing and polarisation mode, which is a necessity when willing to perform a standard InSAR study. Thus, we decided to improve the number of potential SAR scenes by performing a processing on multiple polarisation data. We combine Fine Beam Mode Single Polarisation (FBS) and Fine Beam Mode Dual Polarisation (FBD) data, with a look angle of about 38.7°. We actually can process both these data together at the price of a decrease in spatial resolution but improving the data temporal sampling and dataset population. We then have 13 Single Look Complex (SLC) L-band data spanning 4 years, from 2007/07/07 to 2011/01/15. Besides, the satellite path orientation with respect to the fault orientation is optimal to obtain a suitable InSAR LOS sensitivity to strike-slip surface movement parallel to the NAFZ at the Ganos section. The shallow creep signal is expected to range from ~0 to 1.5 cm/yr. From the 66 initial differential interferograms, we select a subset of 41 high-signal-coherence interferograms as input for the stacking procedure. Our results suggest that the tectonic signal within the velocity map retrieved from ALOS Palsar InSAR presented in this study is hidden beneath a number of interferometric phase contributions. The phase contributions are mainly due Radio Frequency Interferences (RFI) that are emitted from the ground and affect L-band data. RFI bias the amplitude and phase of the L-band signal resulting in serious co-registration problems and stripes on the interferometric phase. To compensate this bias, we apply RFI filtering during the SAR focusing. Unfortunately, the RFI filter application results in image distortions and difficulties in image co-registration. We could anyway measure a number of across fault 20km-length profiles that reveal a displacement gradient of 0.6 cm/yr. Is this due to tectonic movements ? At the present stage, our conclusion is that L-Band SAR data on the Ganos section of the NAFZ are too few and too affected by RFI to allow a robust seismotectonic interpretation. Longer-term data acquisitions are needed and could be provided by the new generation L-Band sensor Alos-2.

Corrosive effects of fluoride on titanium under artificial biofilm.

PubMed

Fukushima, Azusa; Mayanagi, Gen; Sasaki, Keiichi; Takahashi, Nobuhiro

2018-01-01

This study aimed to investigate the effect of sodium fluoride (NaF) on titanium corrosion using a biofilm model, taking environmental pH into account. Streptococcus mutans cells were used as the artificial biofilm, and pH at the bacteria-titanium interface was monitored after the addition of 1% glucose with NaF (0, 225 or 900ppmF) at 37°C for 90min. In an immersion test, the titanium samples were immersed in the NaF solution (0, 225 or 900ppm F; pH 4.2 or 6.5) for 30 or 90min. Before and after pH monitoring or immersion test, the electrochemical properties of the titanium surface were measured using a potentiostat. The amount of titanium eluted into the biofilm or the immersion solution was measured using inductively coupled plasma mass spectrometry. The color difference (ΔE*ab) and gloss of the titanium surface were determined using a spectrophotometer. After incubation with biofilm, pH was maintained at around 6.5 in the presence of NaF. There was no significant change in titanium surface and elution, regardless of the concentration of NaF. After immersion in 900ppm NaF solution at pH 4.2, corrosive electrochemical change was induced on the surface, titanium elution and ΔE*ab were increased, and gloss was decreased. NaF induces titanium corrosion in acidic environment in vitro, while NaF does not induce titanium corrosion under the biofilm because fluoride inhibits bacterial acid production. Neutral pH fluoridated agents may still be used to protect the remaining teeth, even when titanium-based prostheses are worn. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Fluoride exposure changed the structure and the expressions of Y chromosome related genes in testes of mice.

PubMed

Cao, Jinling; Chen, Yan; Chen, Jianjie; Yan, Hanghang; Li, Meiyan; Wang, Jundong

2016-10-01

It is known that during spermatogenesis, pluripotent germ cells differentiate to become efficient delivery vehicles to the oocyte of paternal DNA, and the process is easily damaged by external poison. In this study, the effects of fluoride on the body weight, fluoride content in femur, testosterone levels in serum and testis, sperm quality, and the expressions of Y chromosome microdeletion genes and protein levels were examined in testes of Kunming male mice treated with different concentrations of 0, 25, 50, 100 mg/L of NaF in drinking water for 11 weeks, respectively. The results showed that compared with the control group, fluoride contents in three treatment groups were significantly increased and the structure of testes was seriously injured. The testosterone contents and the sperm count were decreased. Sperm malformation ratio was distinctly elevated. The expressions of Sly and HSF2 mRNA were markedly reduced in 100 mg/L NaF group and Ssty2 mRNA expression was dramatically decreased in 50 and 100 mg/L NaF groups. Meanwhile, the protein levels of Ssty2 and Sly were significantly reduced in 50 and 100 mg/L NaF groups and HSF2 protein levels were significantly decreased in 100 mg/L NaF group. These studies indicated that fluoride had toxic effects on male reproductive system by reducing the testosterone and sperm count, and increasing the sperm malformation ratio, supported by the damage of testicular structure, as a consequence of depressed HSF2 level, which resulted in the down-regulation of Ssty2 and Sly mRNA and protein. Copyright © 2016 Elsevier Ltd. All rights reserved.

The unique fold and lability of the [2Fe-2S] clusters of NEET proteins mediate their key functions in health and disease.

PubMed

Karmi, Ola; Marjault, Henri-Baptiste; Pesce, Luca; Carloni, Paolo; Onuchic, Jose' N; Jennings, Patricia A; Mittler, Ron; Nechushtai, Rachel

2018-02-12

NEET proteins comprise a new class of [2Fe-2S] cluster proteins. In human, three genes encode for NEET proteins: cisd1 encodes mitoNEET (mNT), cisd2 encodes the Nutrient-deprivation autophagy factor-1 (NAF-1) and cisd3 encodes MiNT (Miner2). These recently discovered proteins play key roles in many processes related to normal metabolism and disease. Indeed, NEET proteins are involved in iron, Fe-S, and reactive oxygen homeostasis in cells and play an important role in regulating apoptosis and autophagy. mNT and NAF-1 are homodimeric and reside on the outer mitochondrial membrane. NAF-1 also resides in the membranes of the ER associated mitochondrial membranes (MAM) and the ER. MiNT is a monomer with distinct asymmetry in the molecular surfaces surrounding the clusters. Unlike its paralogs mNT and NAF-1, it resides within the mitochondria. NAF-1 and mNT share similar backbone folds to the plant homodimeric NEET protein (At-NEET), while MiNT's backbone fold resembles a bacterial MiNT protein. Despite the variation of amino acid composition among these proteins, all NEET proteins retained their unique CDGSH domain harboring their unique 3Cys:1His [2Fe-2S] cluster coordination through evolution. The coordinating exposed His was shown to convey the lability to the NEET proteins' [2Fe-2S] clusters. In this minireview, we discuss the NEET fold and its structural elements. Special attention is given to the unique lability of the NEETs' [2Fe-2S] cluster and the implication of the latter to the NEET proteins' cellular and systemic function in health and disease.

Development of a sustained fluoride delivery system.

PubMed

Baturina, Olga; Tufekci, Eser; Guney-Altay, Ozge; Khan, Shadeed M; Wnek, Gary E; Lindauer, Steven J

2010-11-01

To develop a novel delivery system by which fluoride incorporated into elastomeric rings, such as those used to ligate orthodontic wires, will be released in a controlled and constant manner. Polyethylene co-vinyl acetate (PEVA) was used as the model elastomer. Samples (N = 3) were prepared by incorporating 0.02 to 0.4 g of sodium fluoride (NaF) into previously prepared PEVA solution. Another group of samples prepared in the same manner were additionally dip-coated in PEVA to create an overcoat. Fluoride release studies were conducted in vitro using an ion selective electrode over a period of 45 days. The amount of fluoride released was compared to the optimal therapeutic dose of 0.7 microg F(-)/ring/d. Only coated samples with the highest fluoride content (group D, 0.4 g of NaF) were able to release fluoride at therapeutic levels. When fluoride release from coated and uncoated samples with the same amount of NaF were compared, it was shown that the dip-coating technique resulted in a fluoride release in a controlled manner while eliminating the initial burst effect. This novel fluoride delivery matrix provided fluoride release at a therapeutically effective rate and profile.

Protective effects of selenium on fluoride induced alterations in certain enzymes in brain of mice.

PubMed

Reddy, K Pratap; Sailaja, G; Krishnaiah, Chirumari

2009-09-01

This study reports the protective effects of selenium on fluoride induced alterations in the activities of pro-oxidative (xanthine oxidase (XOD), lipid peroxidation (LPO) free radical scavenging, [catalase, superoxide dismutase (SOD), glutathione-s-transferase (GST), glutathione peroxidase (GPX), glutathione reductase (GR), glutathione) and metabolic (glucose-6-phosphate dehydrogenase, alanine amino transferase (ALAT), aspartate aminotransferase (AAT), creatine phosphokinase (CPK), acid phosphatase (AP), alkaline phosphatase (ALP)] enzymes along with fluoride and selenium levels in brain of mice. Animals were divided into control, NaF treated group (20 mg kg(-1) body wt.(-1) intraperitonial) and Selenium+NaF treated group (sodium selenite, 5 microg of selenium/0.2 ml distilled water kg(-1) body wt.(-1) day) and were maintained for 14 days on respective treatments. The decreased bodyweight (-11.35%) as well as organosomatic index (-15.1%) of brain in NaF group were recovered in treatment of selenium along with NaF. The increased accumulation of fluoride (32.1%) in brain observed in NaF treated group compared to control was diminished in selenium+NaF treated group. Selenium levels (3.03%) increased in selenium+NaF treated group in compared to decrement in NaF treatment. The SOD (-16.6%), Catalase (-21.5%), GST(-13.72%), GPX (-19.16%), GR (-44.97%) activities and Glutathione (-23%) content in NaF treated group were decreased significantly compared to controls, which were significantly (p < 0.01) recovered in selenium+NaF group. Increased XOD (10.85%) and LPO (8.61%) levels observed in brain of NaF treated mice were reversed with selenium treatment. Glucose-6-phosphate dehydrogenase (-46.98%), ALAT (-10.44%), AAT (-10.21%), CPK (-27.98%) were decreased and alkaline phosphatase (10.6%), acid phosphatase (24.09%) increased in brain of mice after administration of NaF. All metabolic enzymes were significantly (p < 0.01) reversed after administration of selenium to the NaF treated group. Thus, the adverse effects of NaF on oxidative and metabolic enzymes of brain were reversible with ameliorative action of selenium supplementation. As evident in this study the antioxidative nature of selenium coupled with its reversal effect on metabolic enzymes in brain of mice treated with fluoride suggests its use as antidote agent against fluorosis.

WE-H-207A-05: Spatial Co-Localization of F-18 NaF Vs. F-18 FDG Defined Disease Volumes

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

Ferjancic, P; Harmon, S; Jeraj, R

Purpose: Both [F-18]NaF and [F-18]FDG show promise for quantitative PET/CT assessment in metastatic prostate cancer to bone. Broad agreement between the tracers has been shown but voxel-wise correspondence has not been explored in depth. This study evaluates the spatial co-localization of [F-18]NaF PET and [F-18]FDG PET in bone lesions. Methods: Seventy-three lesion contours were identified in six patients receiving dynamic NaF PET/CT and FDG PET/CT scans two hours apart using identical fields-of-view. Tracer uptake (SUV) reflecting 60 minutes post-injection was modeled from kinetic parameters. Lesions were segmented by a physician separately on NaF PET and FDG PET. PET images weremore » rigidly aligned using skeletal references on CT images. Lesion size, degree of overlap, voxel-wise tracer uptake values (SUV), and CT density distributions were compared using Dice coefficient, Positive Predictive Value (PPV), and Spearman rank correlation tests. Results: Across all patients, 42 lesions were identified on NaF PET (median 1.4 cm{sup 3}, range <1–204 cm{sup 3}) compared to 31 using FDG PET (median 1.8 cm{sup 3}, range <1–244 cm{sup 3}). Spatial cooccurrence was found in 25 lesion pairs. Lesions on NaF PET had PPV of 0.91 and on FDG a PPV of 0.65. Overall, NaF-defined lesions were 47% (±24%) larger by volume with moderate overlap to FDG, resulting in mean Dice coefficient of 34% (±22%). In areas of overlap, voxel-wise correlation of NaF and FDG SUV was moderate (ρ=0.56). Expanding to regions of non-spatial overlap, voxels contained in FDG-only contours were almost exclusively low HU (median 118), compared to dense regions of NaF-only voxels (median 250). In sclerotic sub-volumes (HU > 300) NaF-defined contours encompassed 83% of total FDG volume. Conclusion: Moderate voxel-wise correlation of FDG and NaF PET/CT uptake was observed. Spatial discrepancies in FDG and NaF PET/CT imaging of boney metastases could be influenced by poor sensitivity of FDG PET/CT in sclerotic regions. Funded by Prostate Cancer Foundation.« less

Sustaining Service Members and Their Families: Exploring Opportunities for Efficiency and Joint Provision of Services Using Nonappropriated Funds

DTIC Science & Technology

2016-05-31

do not necessarily reflect the opinions of its research clients and sponsors. Support RAND Make a tax -deductible charitable contribution at...This report con- tains the results of that analysis, looking at the areas of NAF accounting and NAF employee benefits in terms of best practices in...5 CHAPTER TWO Program Area Descriptions: NAF Accounting

Texture and acceptability of goat meat frankfurters processed with 3 different sources of fat.

PubMed

Bratcher, C L; Dawkins, N L; Solaiman, S; Kerth, C R; Bartlett, J R

2011-05-01

The objective of this research was to evaluate the texture and consumer acceptability of goat meat frankfurter formulations with no added fat (NAF), beef fat (BF), or canola oil (CO). Consumer sensory evaluation, fat, and moisture and texture profile analyses were performed on goat meat frankfurters produced with the fat sources BF, CO, and NAF. For sensory evaluations, NAF was less tender (P = 0.007; 4.90 vs. 4.11 and 4.35 for BF and CO, respectively) and the flavor was liked less (P = 0.004; 4.59 vs. 3.83 and 4.30 for BF and CO, respectively); BF was scored as the juiciest (P = 0.003; 3.86 vs. 4.49 and 4.58 for CO and NAF, respectively); and CO had the least amount of flavor (P = 0.029; 3.65 vs. 3.12 and 3.10 for BF and NAF, respectively). Moisture was least (P < 0.001) in CO (46.59%), followed by BF (48.57%) and NAF (55.80%). The amount of fat was not different (P = 0.761) in BF (24.36%) or CO (24.43%) but was less (P < 0.001) in NAF (9.06%), as expected. The NAF had the most protein (P < 0.001; 34.14%), followed by CO (27.98%) and BF (26.07%). For texture profile analyses, NAF had the least hardness value (P = 0.008; 3.92 vs. 4.48 and 4.40 for BF and CO, respectively) and least chewiness value (P = 0.026; 2.89 vs. 3.39 and 3.29 for BF and CO, respectively). Beef fat and CO were not different for hardness (P = 0.596) or chewiness (P = 0.530). No differences were observed in springiness (P = 0.954) or resilience (P = 0.561). The sensory panelists tended to prefer BF for overall acceptability. Results from these data revealed that value-added goat meat products received acceptable sensory scores; therefore, continued research and development will greatly expand the knowledge of goat meat and increase the acceptance of value-added products.

Effect of Sodium Fluoride Ingestion on Malondialdehyde Concentration and the Activity of Antioxidant Enzymes in Rat Erythrocytes

PubMed Central

Morales-González, José A.; Gutiérrez-Salinas, José; García-Ortiz, Liliana; del Carmen Chima-Galán, María; Madrigal-Santillán, Eduardo; Esquivel-Soto, Jaime; Esquivel-Chirino, César; González-Rubio, Manuel García-Luna y

2010-01-01

Fluoride intoxication has been shown to produce diverse deleterious metabolic alterations within the cell. To determine the effects of sodium fluoride (NaF) treatment on malondialdehyde (MDA) levels and on the activity of antioxidant enzymes in rat erythrocytes, Male Wistar rats were treated with 50 ppm of NaF or were untreated as controls. Erythrocytes were obtained from rats sacrificed weekly for up to eight weeks and the concentration of MDA in erythrocyte membrane was determined. In addition, the activity of the enzymes superoxide, dismutase, catalase, and glutathione peroxidase were determined. Treatment with NaF produces an increase in the concentration of malondialdehyde in the erythrocyte membrane only after the eight weeks of treatment. On the other hand, antioxidant enzyme activity was observed to increase after the fourth week of NaF treatment. In conclusion, intake of NaF produces alterations in the erythrocyte of the male rat, which indicates induction of oxidative stress. PMID:20640162

Cu(In,Ga)Se2 surface treatment with Na and NaF: A combined photoelectron spectroscopy and surface photovoltage study in ultra-high vacuum

NASA Astrophysics Data System (ADS)

Parvan, V.; Mizrak, A.; Majumdar, I.; Ümsür, B.; Calvet, W.; Greiner, D.; Kaufmann, C. A.; Dittrich, T.; Avancini, E.; Lauermann, I.

2018-06-01

Either metallic Na or NaF were deposited onto Cu(In,Ga)Se2 surfaces and studied by photoelectron spectroscopy and surface photovoltage spectroscopy without breaking the ultra-high vacuum. The deposition of elemental Na at room temperature led to the formation of an intermediate Cu and Ga rich layer at the CIGSe surface, whereas for NaF the composition of the CIGSe surface remained unchanged. A metal like surface induced by an inverted near surface region with a reduced number of defect states was formed after the deposition of Na. Under the chosen experimental conditions, the near surface layer was independent on the amount of Na and stable in time. In contrast, the usage of NaF weakened the inversion and led to an increased band bending compared to the untreated CIGSe sample. The SPV signals decreased with proceeding time after the deposition of NaF.

Results from the latest SN-4 multi-parametric benthic observatory experiment (MARsite EU project) in the Gulf of Izmit, Turkey: oceanographic, chemical and seismic monitoring

NASA Astrophysics Data System (ADS)

Embriaco, Davide; Marinaro, Giuditta; Frugoni, Francesco; Giovanetti, Gabriele; Monna, Stephen; Etiope, Giuseppe; Gasperini, Luca; Çağatay, Namık; Favali, Paolo

2015-04-01

An autonomous and long-term multiparametric benthic observatory (SN-4) was designed to study gas seepage and seismic energy release along the submerged segment of the North Anatolian Fault (NAF). Episodic gas seepage occurs at the seafloor in the Gulf of Izmit (Sea of Marmara, NW Turkey) along this submerged segment of the NAF, which ruptured during the 1999 Mw7.4 Izmit earthquake. The SN-4 observatory already operated in the Gulf of Izmit at the western end of the 1999 Izmit earthquake rupture for about one-year at 166 m water depth during the 2009-2010 experiment (EGU2014-13412-1, EGU General Assembly 2014). SN-4 was re-deployed in the same site for a new long term mission (September 2013 - April 2014) in the framework of MARsite (New Directions in Seismic Hazard assessment through Focused Earth Observation in the Marmara Supersite, http://marsite.eu/ ) EC project, which aims at evaluating seismic risk and managing of long-term monitoring activities in the Marmara Sea. A main scientific objective of the SN-4 experiment is to investigate the possible correlations between seafloor methane seepage and release of seismic energy. We used the same site of the 2009-2010 campaign to verify both the occurrence of previously observed phenomena and the reliability of results obtained in the previous experiment (Embriaco et al., 2014, doi:10.1093/gji/ggt436). In particular, we are interested in the detection of gas release at the seafloor, in the role played by oceanographic phenomena in this detection, and in the association of gas and seismic energy release. The scientific payload included, among other instruments, a three-component broad-band seismometer, and gas and oceanographic sensors. We present a technical description of the observatory, including the data acquisition and control system, results from the preliminary analysis of this new multidisciplinary data set, and a comparison with the previous experiment.

Toxicity assessment of sodium fluoride in Drosophila melanogaster after chronic sub-lethal exposure.

PubMed

Dutta, Moumita; Rajak, Prem; Khatun, Salma; Roy, Sumedha

2017-01-01

Sodium fluoride (NaF), one of the most frequently used fluoride compound is composed of Na + and F - . Apart from its use in water fluoridation, NaF also acts as a major component for different dental products like toothpastes, gels and mouth rinses etc. The present study was carried out to explore the toxic impact of chronic NaF exposure on a non-target organism, Drosophila melanogaster. The larvae exposed to different concentrations of NaF through food showed a significant increase in HSP70 expression both qualitatively and quantitatively. The altered tail length and tail intensity in Comet assay validate the increased DNA damage in treated larvae. The activity of AChE, oxidative stress marker enzymes, phase I and phase II detoxifying enzymes were found to be significantly inhibited in the treated larvae when compared to control though there was no evidence of dose dependent change in each case. The alterations in the mentioned parameters can be due to increased body Fluoride ion (F - ) concentration since the analysis with ion electrode analyzer revealed that F - concentration increased significantly with NaF treatment. Hence, the results suggest that D. melanogaster manifest prominent toxic response when subjected to chronic exposure to sub-lethal NaF concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

The toxic effect of sodium fluoride on Spodoptera frugiperda 9 cells and differential protein analysis following NaF treatment of cells.

PubMed

Zuo, Huan; Chen, Liang; Kong, Ming; Yang, Yanhua; Lü, Peng; Qiu, Lipeng; Wang, Qiang; Ma, Shangshang; Chen, Keping

2018-05-01

Accumulation of excess fluoride has a destructive effect on the environment, endangering human health, affecting organism growth and development, and leading to damage to the biological chain, thereby affecting ecological environment balance. In recent years, numerous studies focused on the molecular mechanisms associated with fluoride toxicity; however, fluoride-toxicity mechanisms in insect cells remain unclear. This study explored the toxic impact of sodium fluoride (NaF) on Spodoptera frugiperda 9 (Sf9) insect cells. High concentrations of NaF (10 -4  M, 10 -3  M and 10 -2  M) resulted in cell enlargement, cell membrane blurring and breakage, and release of cellular contents. Dose-response curves indicated that NaF-specific inhibition rates on Sf9-cell activity increased along with increases in NaF concentration, with a half-inhibitory concentration (IC 50 ) for NaF of 5.919 × 10 -3  M at 72 h. Compared with controls, the percentages of early and late apoptotic and necrotic cells clearly increased based on observed increases in NaF concentrations. Two-dimensional gel electrophoresis combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to detect differentially expressed proteins in Sf9 cells treated with IC 50 NaF, identifying 17 proteins, seven of which were upregulated and 10 downregulated. These results demonstrated that Sf9 cells showed signs of NaF-mediated toxicity through alterations in cell morphology, apoptosis rates, and protein expression. Copyright © 2018 Elsevier Ltd. All rights reserved.

TiF(4) and NaF at pH 1.2 but not at pH 3.5 are able to reduce dentin erosion.

PubMed

Wiegand, Annette; Magalhães, Ana Carolina; Sener, Beatrice; Waldheim, Elena; Attin, Thomas

2009-08-01

This study aimed to analyse and compare the protective effect of buffered (pH 3.5) and native (pH 1.2) TiF(4) in comparison to NaF solutions of same pH on dentin erosion. Bovine samples were pretreated with 1.50% TiF(4) or 2.02% NaF (both 0.48M F) solutions, each with a pH of 1.2 and 3.5. The control group received no fluoride pretreatment. Ten samples in each group were eroded with HCl (pH 2.6) for 10x60s. Erosion was analysed by determination of calcium release into the acid. Additionally, the surface and the elemental surface composition were examined by scanning electron microscopy (two samples in each group) and X-ray energy-dispersive spectroscopy in fluoridated but not eroded samples (six samples in each group). Cumulative calcium release (nmol/mm(2)) was statistically analysed by repeated measures ANOVA and one-way ANOVA at t=10min. TiF(4) and NaF at pH 1.2 decreased calcium release significantly, while TiF(4) and NaF at pH 3.5 were not effective. Samples treated with TiF(4) at pH 1.2 showed a significant increase of Ti, while NaF pretreatment increased F concentration significantly. TiF(4) at pH 1.2 led to the formation of globular precipitates occluding dentinal tubules, which could not be observed on samples treated with TiF(4) at pH 3.5. NaF at pH 1.2 but not at pH 3.5 induced the formation of surface precipitates covering dentinal tubules. Dentin erosion can be significantly reduced by TiF(4) and NaF at pH 1.2, but not at pH 3.5.

Caries-Preventive Effect of NaF, NaF plus TCP, NaF plus CPP-ACP, and SDF Varnishes on Sound Dentin and Artificial Dentin Caries in vitro.

PubMed

Wierichs, Richard J; Stausberg, Sabrina; Lausch, Julian; Meyer-Lueckel, Hendrik; Esteves-Oliveira, Marcella

2018-01-01

The aim of this study was to compare the caries-preventive effect of different fluoride varnishes on sound dentin as well as on artificial dentin caries-like lesions. Bovine dentin specimens (n = 220) with one sound surface (ST) and one artificial caries lesion (DT) were prepared and randomly allocated to 11 groups. The interventions before pH cycling were as follows: application of a varnish containing NaF (22,600 ppm F-; Duraphat [NaF0/NaF1]), NaF plus tricalcium phosphate (22,600 ppm F-; Clinpro White Varnish Mint [TCP0/TCP1]), NaF plus casein phosphopeptide-stabilized amorphous calcium phosphate complexes (CPP-ACP; 22,600 ppm F-; MI Varnish [CPP0/CPP1]), or silver diamine fluoride (SDF; 35,400 ppm F-; Cariestop 30% [SDF0/SDF1]) and no intervention (NNB/N0/N1). During pH cycling (14 days, 6 × 120 min demineralization/day) half of the specimens in each group were brushed (10 s; 2 times/day) with either fluoride-free ("0"; e.g., TCP0) or 1,100 ppm F- ("1"; e.g., TCP1) dentifrice slurry. In another subgroup, the specimens were pH cycled but not brushed (NNB). Differences in integrated mineral loss (ΔΔZ), lesion depth (ΔLD), and colorimetric values (ΔΔE) were calculated between the values after initial demineralization and those after pH cycling, using transversal microradiography and photographic images. After pH cycling, no discoloration could be observed. Furthermore, NNB, N0, and N1 showed significantly increased ΔZDT/LDDT and ΔZST/LDST values, indicating further demineralization. In contrast, CPP0, CPP1, SDF0, and SDF1 showed significantly decreased ΔZDT/LDDT values, indicating remineralization (p ≤ 0.004; paired t test). CPP0, CPP1, SDF0, and SDF1 showed significantly higher changes in ΔΔZDT/ΔLDDT and ΔΔZST/ΔLDST than NNB, N0, and N1 (p < 0.001; Bonferroni post hoc test). In conclusion, under the conditions chosen, all fluoride varnishes prevented further demineralization. However, only NaF plus CPP-ACP and SDF could remineralize artificial dentin caries-like lesions under net-demineralizing conditions, thereby indicating that NaF plus CPP-ACP and SDF may be helpful to high-caries-risk patients. © 2018 S. Karger AG, Basel.

Fluoride rinse effect on retention of CaF2 formed on enamel/dentine by fluoride application.

PubMed

Falcão, Amanda; Masson, Nadia; Leitão, Tarcísio Jorge; Botelho, Juliana Nunes; Ferreira-Nóbilo, Naiara de Paula; Tabchoury, Cínthia Pereira Machado; Tenuta, Livia Maria Andaló; Cury, Jaime Aparecido

2016-01-01

Calcium fluoride-like materials ("CaF2") formed on dental surfaces after professional fluoride application are unstable in the oral environment but can be retained longer with a daily NaF mouthrinse. We tested the effect of twice daily 0.05% NaF rinses on the retention of "CaF2" formed on enamel and dentine after applying acidulated phosphate fluoride (APF). "CaF2" formed on enamel/dentine by APF application significantly decreased after exposure to artificial saliva and the 0.05% NaF rinse was ineffective to avoid this reduction. These findings suggest that the combination of APF and 0.05% NaF is not clinically relevant, either for caries or dental hypersensitivity.

Pilot of the Modern Army Recordkeeping System (MARKS) at Headquarters, U.S. Army Armor Center and Fort Knox, Fort Knox, Kentucky, January-December 1984.

DTIC Science & Technology

1985-05-01

Clothing and Textile Materiel 341 Standardization 36 Audit 37 Financial Administration 410 Medical Services 50 Nuclear and Chemical Weapons and Materiel 55...Transaction Files 314-18 210-60b NAF Report of Audit Files 314-27 36-5a NAF Payroll Control Files 36-75a 316-01 36-2a GAO Audit Reporting Files 36-5b 316-02...ll-7a Internal Review Files 316-03 36-5c AAA Audit Reporting Files 316-15 36-5d DAS Audit Reporting Files 319-12 37-107a Commercial Account Claim

Assessment of nickel titanium and beta titanium corrosion resistance behavior in fluoride and chloride environments.

PubMed

Kassab, Elisa J; Gomes, José Ponciano

2013-09-01

To assess the influence of fluoride concentration on the corrosion behavior of nickel titanium (NiTi) superelastic wire and to compare the corrosion resistance of NiTi with that of beta titanium alloy in physiological solution with and without addition of fluoride. NiTi corrosion resistance was investigated through electrochemical impedance spectroscopy and anodic polarization in sodium chloride (NaCl 0.15 M) with and without addition of 0.02 M sodium fluoride (NaF), and the results were compared with those associated with beta titanium. The influence of fluoride concentration on NiTi corrosion behavior was assessed in NaCl (0.15 M) with and without 0.02, 0.04, 0.05, 0.07, and 0.12 M NaF solution. Galvanic corrosion between NiTi and beta titanium were investigated. All samples were characterized by scanning electron microscopy. Polarization resistance decreased when NaF concentration was increased, and, depending on NaF concentration, NiTi can suffer localized or generalized corrosion. In NaCl solution with 0.02 M NaF, NiTi suffer localized corrosion, while beta titanium alloys remained passive. Current values near zero were observed by galvanic coupling of NiTi and beta titanium. There is a decrease in NiTi corrosion resistance in the presence of fluoride. The corrosion behavior of NiTi alloy depends on fluoride concentration. When 0.02 and 0.04 M of NaF were added to the NaCl solution, NiTi presented localized corrosion. When NaF concentration increased to 0.05, 0.07, and 0.12 M, the alloy presented general corrosion. NiTi corrosion resistance behavior is lower than that of beta titanium. Galvanic coupling of these alloys does not increase corrosion rates.

The volume of nipple aspirate fluid is not affected by 6 months of treatment with soy foods in premenopausal women.

PubMed

Maskarinec, Gertraud; Morimoto, Yukiko; Conroy, Shannon M; Pagano, Ian S; Franke, Adrian A

2011-04-01

Based on the hypothesis that soy food consumption may influence breast tissue activity, we examined its effect on the production of nipple aspirate fluid (NAF), a possible indicator of breast cancer risk. Of 310 premenopausal women screened, 112 (36%) produced at least 10 μL of NAF, the minimum for study participation. In a crossover design, we randomized 96 women to 2 groups who, in reverse order, consumed a high-soy diet with 2 soy servings/d (1 serving = 177 mL soy milk, 126 g tofu, or 23 g soy nuts) and a low-soy diet with <3 servings/wk of soy for 6 mo each separated by a 1-mo washout period. During each diet period, 3 NAF samples were obtained (baseline and 3 and 6 mo) using a FirstCyte Aspirator and 4 urine samples (baseline and 1, 3, and 6 mo) were analyzed for isoflavonoids by liquid chromatography tandem MS. Adherence to the study protocol according to 24-h dietary recalls and urinary isoflavonoid excretion was high. The drop-out rate was 15% (n = 14); 82 women completed the intervention. The 2 groups produced similar mean NAF volumes at baseline (P = 0.95) but differed in age and previous soy intake and in their response to the intervention (P = 0.03). In both groups, NAF volume decreased during the first 3 mo of the high-soy diet period and returned to baseline at 6 mo, but there was no effect of the high-soy diet on NAF volume (P = 0.50 for diet; P-interaction = 0.21 for diet with time). Contrary to an earlier report, soy foods in amounts consumed by Asians did not increase breast tissue activity as assessed by NAF volume.

The Volume of Nipple Aspirate Fluid Is Not Affected by 6 Months of Treatment with Soy Foods in Premenopausal Women1234

PubMed Central

Maskarinec, Gertraud; Morimoto, Yukiko; Conroy, Shannon M.; Pagano, Ian S.; Franke, Adrian A.

2011-01-01

Based on the hypothesis that soy food consumption may influence breast tissue activity, we examined its effect on the production of nipple aspirate fluid (NAF), a possible indicator of breast cancer risk. Of 310 premenopausal women screened, 112 (36%) produced at least 10 μL of NAF, the minimum for study participation. In a crossover design, we randomized 96 women to 2 groups who, in reverse order, consumed a high-soy diet with 2 soy servings/d (1 serving = 177 mL soy milk, 126 g tofu, or 23 g soy nuts) and a low-soy diet with <3 servings/wk of soy for 6 mo each separated by a 1-mo washout period. During each diet period, 3 NAF samples were obtained (baseline and 3 and 6 mo) using a FirstCyte Aspirator and 4 urine samples (baseline and 1, 3, and 6 mo) were analyzed for isoflavonoids by liquid chromatography tandem MS. Adherence to the study protocol according to 24-h dietary recalls and urinary isoflavonoid excretion was high. The drop-out rate was 15% (n = 14); 82 women completed the intervention. The 2 groups produced similar mean NAF volumes at baseline (P = 0.95) but differed in age and previous soy intake and in their response to the intervention (P = 0.03). In both groups, NAF volume decreased during the first 3 mo of the high-soy diet period and returned to baseline at 6 mo, but there was no effect of the high-soy diet on NAF volume (P = 0.50 for diet; P-interaction = 0.21 for diet with time). Contrary to an earlier report, soy foods in amounts consumed by Asians did not increase breast tissue activity as assessed by NAF volume. PMID:21325473

The effects of fluoride on neuronal function occurs via cytoskeleton damage and decreased signal transmission.

PubMed

Chen, Lingli; Ning, Hongmei; Yin, Zhihong; Song, Xiaochao; Feng, Yongchao; Qin, Hao; Li, Yi; Wang, Jundong; Ge, Yaming; Wang, Wenkui

2017-10-01

It has been reported that fluoride exposure may cause serious public health problems, particularly neurotoxicity. However, the underlying mechanisms remain unclear. This study used Neuro-2A cells to investigate the effects of fluoride on the cytoskeleton. The Neuro-2A cells were exposed to 0, 1, 2, 4 and 6 mM sodium fluoride (NaF) for 24 h. Cell viability and lactate dehydrogenase (LDH) release were examined. It was observed that exposure to NaF reduced cell viability, disrupted cellular membrane integrity, and high levels of LDH were released. The observed changes occurred in a dose response manner. Morphologic observations showed that cell became rounded and were loosely adherent following exposure to NaF. Axon spines and normal features disappeared with high dose NaF treatment. The expression of MAP2 and synaptophysin decreased, particularly at 4 mM and 6 mM (P < 0.05) for MAP2. These results corroborate the morphologic observations. The content of glutamate and NMDAR (glutamate receptor) protein were assessed to help understand the relationship between synapses and neurotransmitter release using ELISA and Western-blot. Compared with the control, glutamate and NMDAR expression declined significantly at 4 mM and 6 mM (P < 0.05) group. Finally, the ultrastructural changes observed with increasing doses of NaF were: disappearance of synapses, mitochondrial agglutination, vacuole formation, and cellular edema. Taken together, NaF exposure disrupted cellular integrity and suppressed the release of neurotransmitters, thus effecting neuronal function. These findings provide deeper insights into roles of NaF in neuron damage, which could contribute to a better understanding of fluoride-induced neurotoxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of murine bladder permeability with fluorescein: validation with cyclophosphamide and protamine.

PubMed

Eichel, L; Scheidweiler, K; Kost, J; Shojaie, J; Schwarz, E; Messing, E; Wood, R

2001-07-01

Bladder hyperpermeability should result in elevated blood levels of intravesically administered agents. Reabsorption from a hyperpermeable bladder should result in prolonged urinary excretion of an agent after parenteral administration. To test these hypotheses, urinary clearance and plasma levels of sodium fluorescein (NaF) were measured in mice before and during cyclophosphamide (CYP) and protamine-induced hemorrhagic cystitis. To measure the plasma uptake of NaF from the bladder, 10 mg/mL NaF was instilled, either by catheter or retrograde urethral infusion, 15 minutes before retro-orbital or ventricular sampling. The plasma levels were measured 24 hours and 14 days after exposure to CYP 300 mg/kg or 15 minutes after instillation of protamine 10 mg/mL. Hourly urine concentrations were measured immediately after intraperitoneal administration of 10 mg/kg NaF. Pretreatment samples were compared with those obtained 24 hours after intraperitoneal administration of 300 mg/kg CYP. Urinary NaF excretion was delayed in CYP-exposed mice. A bi-exponential model provided an appropriate fit of the data, both before and after CYP administration. The plasma levels of NaF were significantly elevated at 24 hours and 14 days after CYP exposure when sampled by ventricular nick or retro-orbitally. The median concentration of fluorescein in the protamine-treated mice was significantly higher than in the control mice. Fluorescein can be used to measure alterations in bladder permeability after bladder mucosal injury in mice. Urinary excretion of NaF is a bi-exponential process that is delayed after bladder mucosal injury, presumably because of increased mucosal permeability and resorption from the urine into the bloodstream.

Properties of the Ca2+ influx reveal the duality of events underlying the activation by vanadate and fluoride of the Gárdos effect in human red blood cells.

PubMed

Varecka, L; Peterajová, E; Písová, E

1998-08-14

The properties of the 45Ca2+ influx by human red blood cells (RBC) induced by NaVO3 or NaF were compared. The NaVO3-induced 45Ca2+ influx was slower and less extensive than that induced by NaF. Both processes were saturable with Ca2+. Substitution of Na+ by K+ inhibited the 45Ca2+ influx induced by NaVO3 but stimulated that by NaF. The NaVO3-induced Ca2+ influx was sensitive to nifedipine (IC50 = 50 mol/l), Cu2+ (IC50=9 mol/l), DTNB (5,5'-dithiobis-(dinitrobenzoic acid)) (IC50 = 12 mol/l) (maximal inhibition 16%, 18%, and 28%, respectively, if NaF was used as inducer). On the other hand, tetrodotoxin (TTX) and cyclosporin A inhibited only the NaF-induced 45Ca2+ influx (IC50 = 21 mol/l and 28 mol/l, respectively). Pig RBC, known not to display the NaVO3-induced Ca2+ influx, exhibited Ca2+ influx induced by NaF. The results show that NaVO3 activates the Ca2+ influx via a pathway homologous to the L-type Ca2+ channel while the NaF-induced Ca2+ influx is mediated via the TTX-sensitive Na+ channel in the presence of NaF with possible participation of calcineurin or cyclophilin. Thus, the Gardos effect induced by NaVO3 and NaF represents two phenomena activated by different mechanisms present in the cryptic state in the RBC membrane.

Fluoride-induced iron overload contributes to hepatic oxidative damage in mouse and the protective role of Grape seed proanthocyanidin extract.

PubMed

Niu, Qiang; He, Ping; Xu, Shangzhi; Ma, Ruling; Ding, Yusong; Mu, Lati; Li, Shugang

2018-01-01

Emerging evidence has demonstrated that iron overload plays an important role in oxidative stress in the liver. This study aimed to explore whether fluoride-induced hepatic oxidative stress is associated with iron overload and whether grape seed proanthocyanidin extract (GSPE) alleviates oxidative stress by reducing iron overload. Forty Kunming male mice were randomly divided into 4 groups and treated for 5 weeks with distilled water (control), sodium fluoride (NaF) (100 mg/L), GSPE (400 mg/kg bw), or NaF (100 mg/L) + GSPE (400 mg/kg bw). Mice exposed to NaF showed typical poisoning changes of morphology, increased aspartate aminotransferase and alanine aminotransferase activities in the liver. NaF treatment also increased MDA accumulation, decreased GSH-Px, SOD and T-AOC levels in liver, indicative of oxidative stress. Intriguingly, all these detrimental effects were alleviated by GSPE. Further study revealed that NaF induced disorders of iron metabolism, as manifested by elevated iron level with increased hepcidin but decreased ferroportin expression, which contributed to hepatic oxidative stress. Importantly, the iron dysregulation induced by NaF could be normalized by GSPE. Collectively, these data provide a novel insight into mechanisms underlying fluorosis and highlight the potential of GSPE as a naturally occurring prophylactic treatment for fluoride-induced hepatotoxicity associated with iron overload.

Influence of sodium fluoride on the synthesis of hydroxyapatite by gel method

NASA Astrophysics Data System (ADS)

Kanchana, P.; Sekar, C.

2010-03-01

Hydroxyapatite (HA) is a good candidate for bone substitutes due to its chemical and structural similarity to bone mineral. Hydroxyapatite has been grown by the gel method using sodium fluoride (NaF) as additive. The growth was carried out at room temperature under the physiological pH of 7.4. The addition of NaF has significantly reduced growth rate and the yield was much less when compared to pure system. The samples of pure and fluoride doped HA were sintered at 600, 900 and 1200 °C in ambient atmosphere. Scanning electron microscopy (SEM), powder X-ray diffraction (XRD), thermogravimetric analysis (TG) and Fourier transform infrared spectroscopy (FTIR) were adopted to investigate the influence of NaF on the morphology, crystallinity, stability and phase purity of HA. EDAX and FTIR studies confirm that the fluoride is doped into the hydroxyapatite. Powder XRD and TGA results suggested that the incorporation of fluorine into the HA matrix improves the phase formation and crystallinity. SEM studies show that the microstructural morphology of HA changes from the fibers for pure to granular structure for the fluoride doped.

The effects of brushing on human enamel surface roughness after NaF gel and theobromine gel exposure

NASA Astrophysics Data System (ADS)

Mahardhika, A.; Noerdin, A.; Eriwati, Y. K.

2017-08-01

This study aimed to determine the effects of brushing on human enamel surface roughness after different exposure times of 200 mg/L theobromine gel (8, 16, and 32 minutes) and 2% NaF gel (16 minutes). Twenty-four human upper premolars were used and divided into four groups. Group 1 was exposed to 2% NaF gel for 16 minutes. In contrast, groups 2, 3, and 4 were exposed to 200 mg/L theobromine gel for 8 minutes, 16 minutes, and 32 minutes, and each group was then brushed for 9 minutes and 20 seconds. After the treatment, samples were tested using a surface roughness tester (Mitutoyo SJ 301, Japan). The Wilcoxon test showed significant changes (p < 0.05) in roughness values after exposure to the theobromine gel or NaF gel and after brushing for 9 minutes and 20 seconds. It can be concluded that exposure to 200 mg/L theobromine gel or 2% NaF gel can soften the enamel surface and then increase roughness after brushing.

Fluid activity within the North Anatolian Fault Zone according to 3D marine seismic data on the Sea of Marmara Western High

NASA Astrophysics Data System (ADS)

Grall, C.; Henry, P.; Thomas, Y.; Marsset, B.; Westbrook, G.; Saritas, H.; Géli, L.; Ruffine, L.; Dupré, S.; Scalabrin, C.; Augustin, J. M.; Cifçi, G.; Zitter, T.

2012-04-01

Along the northern branch of the North Anatolian Fault Zone (NAFZ) within the Sea of Marmara, numerous gas seeps occur. A large part of the gas origin is biogenic but on the Western High, gas bubbles and gas hydrate with a thermogenic signature have been sampled. The expulsion of deep fluids opened new perspective about the permeability, the mechanical properties and the monitoring of the NAFZ. Consequently, the Western High was selected for the deployment of a 3D seismic acquisition layout during the MARMESONET cruise (2009). Thirty-three km2 of high resolution seismic data (with a frequency content of 50-180 Hz) have been collected within the shear band of the fault. The SIMRAD EM-302 was also operated to detect acoustic anomalies related to the presence of gas bubbles in the water column. Within the upper sedimentary cover (seismic penetration ranges from 100 to 500 m bsf), high seismic amplitude variations of the reflectors allow to identify gas traps and gas pathways. Local high amplitude of negative polarity, such as flat spots and bright spots, are observed. Amplitude anomalies are located above and within anticlines and along normal faults. They often correlate with seafloor manifestations of fluid outflow and gas plumes in the water column. This suggests that gas migrates from depth towards the seafloor along normal faults and permeable strata, and part of it is trapped in anticlines. North of the NAF, seabed mounds, corresponding to active hydrocarbon gas seeps, are aligned along a NE-SW direction. They are linked in depth to buried mud volcanoes with an episodic activity. The last mud eruption activity apparently just before or during the Red-H1 horizon deposition which is a prominent reflector of high amplitude and negative polarity occurring all over the Sea of Marmara. It has been interpreted as a stratigraphic horizon, corresponding to slow sedimentation and high sea-level interglacial period.

32 CFR 536.146 - Claims against nonappropriated fund employees-generally.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) activities. NAF activities include NAF or Army and Air Force Exchange Service (AAFES) facilities, post exchanges, bowling centers, officers and noncommissioned officers' clubs, and other facilities located on...

32 CFR 536.146 - Claims against nonappropriated fund employees-generally.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) activities. NAF activities include NAF or Army and Air Force Exchange Service (AAFES) facilities, post exchanges, bowling centers, officers and noncommissioned officers' clubs, and other facilities located on...

32 CFR 536.146 - Claims against nonappropriated fund employees-generally.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) activities. NAF activities include NAF or Army and Air Force Exchange Service (AAFES) facilities, post exchanges, bowling centers, officers and noncommissioned officers' clubs, and other facilities located on...

32 CFR 536.146 - Claims against nonappropriated fund employees-generally.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) activities. NAF activities include NAF or Army and Air Force Exchange Service (AAFES) facilities, post exchanges, bowling centers, officers and noncommissioned officers' clubs, and other facilities located on...

32 CFR 536.146 - Claims against nonappropriated fund employees-generally.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) activities. NAF activities include NAF or Army and Air Force Exchange Service (AAFES) facilities, post exchanges, bowling centers, officers and noncommissioned officers' clubs, and other facilities located on...

Evaluation of the effects of the solution used for electrochemical dissolution of nickel-titanium endodontic files on dentine structure, microhardness and cell viability.

PubMed

Amaral, C C F; Ormiga, F; Boldrini, L C; Miranda, P G; Mendonça, T A; Granjeiro, J M; Gomes, J A C P

2018-05-15

To evaluate the effects of the [NaF 12 g/L + NaCl 1 g/L] solution used in the electrochemical dissolution process of fractured endodontic files, as well as its NiTi-containing product, on dentine hardness, topography and human fibroblast viability. Sixty single-rooted human teeth were evaluated for dentine microhardness using the Vickers hardness test and the area and number of dentinal tubules by scanning electron microscopy. The samples were divided according to the dentine surface treatment: distilled water; 17% EDTA; [NaF 12 g/L + NaCl 1 g/L]; and 17% EDTA + [NaF 12 g/L + NaCl 1 g/L]. Thirty-six single-rooted human teeth were divided according to the irrigation protocol: Dulbecco's Modified Eagle's Medium + 10% fetal bovine serum; 5.25% NaOCl; [NaF 12 g/L + NaCl 1 g/L]; and [NaF 12 g/L + NaCl 1 g/L+NiTi]. The extracts in contact with the apical foramen were used in the MTT assay to evaluate human fibroblast viability, with dilutions of 100, 50, 25 and 12.5%. Statistical tests used were paired t-tests, one-way ANOVA, Tukey's test, Kruskal-Wallis test and Dunn's post-test. The [NaF 12 g/L + NaCl 1 g/L] solution did not modify the dentine microhardness or the average dentinal tubule area. However, the EDTA induced changes in the dentine structure and microhardness (p<0.05). The [NaF 12 g/L + NaCl 1 g/L] solution and its NiTi-containing product had lower cytotoxicity than NaOCl at dilutions of 25% and 50% (p<0.01). The [NaF 12 g/L + NaCl 1 g/L] solution did not alter dentine microhardness or damage the dentine structure. It also demonstrated lower cytotoxicity than NaOCl. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

The cytotoxic effect of TiF4 and NaF on fibroblasts is influenced by the experimental model, fluoride concentration and exposure time

PubMed Central

Salomão, Priscila Maria Aranda; de Oliveira, Flávia Amadeu; Rodrigues, Paula Danielle; Al-Ahj, Luana Polioni; Gasque, Kellen Cristina da Silva; Jeggle, Pia; Buzalaf, Marilia Afonso Rabelo; de Oliveira, Rodrigo Cardoso; Edwardson, John Michael

2017-01-01

Objective Titanium tetrafluoride (TiF4) has shown promising effect in preventing tooth lesions. Therefore, we compared the cytotoxicity of TiF4 with sodium fluoride (NaF) (already applied in Dentistry) considering different fluoride concentrations, pH values and experimental models. Materials and methods Step 1) NIH/3T3 fibroblasts were exposed to mediums containing NaF or TiF4 (from 0.15 to 2.45% F), both at native and adjusted pH, for 6 h. Step 2) NIH/3T3 were exposed to NaF or TiF4 varnishes with 0.95, 1.95 or 2.45% F (native pH), for 6, 12 or 24 h. We applied MTT (1st and 2nd steps) and Hoescht/PI stain (2nd step) assays. Step 3) NIH/3T3 were exposed to NaF or TiF4 varnish (2.45% F), at native pH, for 6 or 12 h. The cell stiffness was measured by atomic force microscopy (AFM). Results Step 1) All cells exposed to NaF or TiF4 mediums died, regardless of the F concentration and pH. Step 2) Both varnishes, at 1.90 and 2.45% F, reduced cell viability by similar extents (33–86% at 6 h, 35–93% at 12 h, and 87–98% at 24 h) compared with control, regardless of the type of fluoride. Varnishes with 0.95% F did not differ from control. Step 3) TiF4 and NaF reduced cell stiffness to a similar extent, but only TiF4 differed from control at 6 h. Conclusions Based on the results of the 3 experimental steps, we conclude that TiF4 and NaF have similar cytotoxicity. The cytotoxicity was dependent on F concentration and exposure time. This result gives support for testing the effect of TiF4 varnish in vivo. PMID:28614381

Sodium fluoride induces apoptosis in mouse embryonic stem cells through ROS-dependent and caspase- and JNK-mediated pathways

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

Nguyen Ngoc, Tam Dan; Son, Young-Ok; Lim, Shin-Saeng

2012-03-15

Sodium fluoride (NaF) is used as a source of fluoride ions in diverse applications. Fluoride salt is an effective prophylactic for dental caries and is an essential element required for bone health. However, fluoride is known to cause cytotoxicity in a concentration-dependent manner. Further, no information is available on the effects of NaF on mouse embryonic stem cells (mESCs). We investigated the mode of cell death induced by NaF and the mechanisms involved. NaF treatment greater than 1 mM reduced viability and DNA synthesis in mESCs and induced cell cycle arrest in the G{sub 2}/M phase. The addition of NaFmore » induced cell death mainly by apoptosis rather than necrosis. Catalase (CAT) treatment significantly inhibited the NaF-mediated cell death and also suppressed the NaF-mediated increase in phospho-c-Jun N-terminal kinase (p-JNK) levels. Pre-treatment with SP600125 or z-VAD-fmk significantly attenuated the NaF-mediated reduction in cell viability. In contrast, intracellular free calcium chelator, but not of sodium or calcium ion channel blockers, facilitated NaF-induced toxicity in the cells. A JNK specific inhibitor (SP600125) prevented the NaF-induced increase in growth arrest and the DNA damage-inducible protein 45α. Further, NaF-mediated loss of mitochondrial membrane potential was apparently inhibited by pifithrin-α or CAT inhibitor. These findings suggest that NaF affects viability of mESCs in a concentration-dependent manner, where more than 1 mM NaF causes apoptosis through hydroxyl radical-dependent and caspase- and JNK-mediated pathways. -- Highlights: ► The mode of NaF-induced cell death and the mechanisms involved were examined. ► NaF induced mainly apoptotic death of mouse embryonic stem cells (mESCs). ► NaF induced mitochondrial-mediated and caspase-dependent apoptosis. ► JNK- and p53-mediated pathways are involved in NaF-mediated apoptosis in the cells. ► ROS are the up-stream effector in NaF-mediated activation of JNK and p53 in mESCs.« less

Antibacterial Effects of Toothpastes Evaluated in an 
In Vitro Biofilm Model.

PubMed

Fernández, Eva; Sánchez, María Del Carmen; Llama-Palacios, Arancha; Sanz, Mariano; Herrera, David

To test the antibacterial effects of different toothpastes with the slurry method of toothpaste application in an in vitro oral biofilm model including relevant periodontal pathogens. Four commercially available toothpastes, two containing sodium fluoride (NaF) at different concentrations (1450 and 2500 ppm), two NaF with either triclosan or stannous fluoride, and a control phosphate-buffered saline (PBS) were used. Multispecies biofilms containing 6 species of oral bacteria were grown on hydroxyapatite disks for 72 h and then exposed for 2 min to the toothpaste slurries or phosphate buffer saline (PBS) by immersion, under continuous agitation at 37°C. Biofilms were then analysed by means of real-time polymerase chain reaction (PCR), combined with propidium monoazide (PMA). Statistical evaluation was performed using ANOVA and Student's t-test, with Bonferroni correction for multiple comparisons. The toothpastes containing NaF and stannous fluoride demonstrated superior antimicrobial activity for A. actinomycetencomitans, P. gingivalis and F. nucleatum when compared to those containing NaF and triclosan, 1450 ppm NaF or 2500 ppm NaF in this multispecies biofilm model. The proposed model for the evaluation of toothpastes in the form of slurries detected significant differences in the antimicrobial effects among the tested NaF-containing toothpastes, with the stannous fluoride-based formulation achieving better results than the other formulations. The use of toothpaste as slurries and real-time PCR with PMA is an adequate method for comparing the in vitro antimicrobial effect of different toothpastes.

Dentin bonding performance and interface observation of an MMA-based restorative material.

PubMed

Shinagawa, Junichi; Inoue, Go; Nikaido, Toru; Ikeda, Masaomi; Sadr, Alireza; Tagami, Junji

2016-07-30

The purpose of this study was to evaluate bonding performance and dentin interface acid resistance using a 4-META/MMA-TBB based restorative material (BF) compared to a conventional 4-META/MMA-TBB resin cement (SB), and the effect of sodium fluoride (NaF) addition to the materials. Dentin surfaces were treated with 10% citric acid-3% ferric chloride (10-3) or 4-META containing self-etching primer (TP), followed by application of BF or SB polymer powders with or without NaF, to evaluate microtensile bond strength (µTBS) in six experimental groups; 10-3/SB, 10-3/BF, TP/SB, TP/BF, TP/SB/NaF and TP/BF/NaF. SEM observation of the resin-dentin interface was performed after acid-base challenge to evaluate interfacial dentin resistance to acid attack. TP/BF showed highest µTBS, while NaF polymers decreased µTBS. TP/BF showed funnel-shaped erosion at the interface, however, NaF polymers improved acid resistance of interface. In conclusion, BF demonstrated high µTBSs and low acid-resistance at the interface. NaF addition enhanced acid resistance but decreased µTBS.

Identification of the need for home visiting nurse: development of a new assessment tool.

PubMed

Taguchi, Atsuko; Nagata, Satoko; Naruse, Takashi; Kuwahara, Yuki; Yamaguchi, Takuhiro; Murashima, Sachiyo

2014-01-01

To develop a Home Visiting Nursing Service Need Assessment Form (HVNS-NAF) to standardize the decision about the need for home visiting nursing service. The sample consisted of older adults who had received coordinated services by care managers. We defined the need for home visiting nursing service by elderly individuals as the decision of the need by a care manager so that the elderly can continue to live independently. Explanatory variables included demographic factors, medical procedure, severity of illness, and caregiver variables. Multiple logistic regression was carried out after univariate analyses to decide the variables to include and the weight of each variable in the HVNS-NAF. We then calculated the sensitivity and specificity of each cutoff value, and defined the score with the highest sensitivity and specificity as the cutoff value. Nineteen items were included in the final HVNS-NAF. When the cutoff value was 2 points, the sensitivity was 77.0%, specificity 68.5%, and positive predictive value 56.8%. HVNS-NAF is the first validated standard based on characteristics of elderly clients who required home visiting nursing service. Using the HVNS-NAF may result in reducing the unmet need for home visiting nursing service and preventing hospitalization.

Post-Seismic Crustal Deformation Following The 1999 Izmit Earthquake, Western Part Of North Anatolian Fault Zone, Turkey

NASA Astrophysics Data System (ADS)

Gurkan, O.; Ozener, H.

2004-12-01

The North Anatolian Fault is an about 1500 km long, extending from the Karliova to the North Aegean. Turkey is a natural laboratory with high tectonic activity caused by the relative motion of the Eurasian, Arabian and Anatolian plates. Western part of Turkey and its vicinity is a seismically active area. Since 1972 crustal deformation has been observed by various kinds of geodetic measurements in the area. Three GPS networks were installed in this region by Geodesy Department of Kandilli Observatory and Earthquake Research Institute( KOERI ) of Bogazici University: (1) Iznik Network, installed on the Iznik-Mekece fault zone, seismically low active part, (2) Sapanca Network, installed on the Izmit-Sapanca fault zone, seismically active part, (3) Akyazi Network, installed on their intersection area, the Mudurnu fault zone. First period observations were performed by using terrestrial methods in 1990 and these observations were repeated annually until 1993. Since 1994, GPS measurements have been carried out at the temporary and permanent points in the area and the crustal movements are being monitored. Horizontal deformations, which have not been detected by terrestrial methods, were determined from the results of GPS measurements. A M=7.4 earthquake hit Izmit, northern Turkey, on August 17, 1999. After this earthquake many investigations have been started in the region. An international project has been performed with the collaboration of Massachussets Institute of Technology, Turkish General Command of Mapping, Istanbul Technical University, TUBITAK-Marmara Research Center and Geodesy Department of KOERI. Postseismic movements have been observed by the region-wide network. A GPS network including 49 well spread points in Marmara region was observed twice a year between 1999 and 2003 years. During these surveys, another network with 6 points has been formed by using 2 points from each 3 microgeodetic networks on NAFZ with appropriate coverage and geometry. These points have been connected by GPS observations to monitor the deformations. This expanded microgeodetic network has been occupied with Istanbul-Kandilli continuous GPS station (KANT). The objective of this paper is to present the post-seismic crustal deformation obtained from the GPS observations at the Western Part of the North Anatolian Fault (NAF) in Turkey.

Postseismic deformation of the 1999 Izmit Earthquake (Turkey) - the longest recorded afterslip on a major continental fault

NASA Astrophysics Data System (ADS)

Cakir, Z.; Aslan, G.; Cetin, S.; Dogan, U.; Ergintav, S.; Lasserre, C.; Renard, F.; Reilinger, R. E.

2017-12-01

Studies based on InSAR and GPS observations until 2012 have shown that the central segment of the August 17, 1999 Izmit earthquake rupture on the North Anatolian Fault (NAF) began slipping aseismically following the event. To monitor this long-lasting afterslip and characterize its spatio-temporal behaviour, we calculated InSAR time series based on a single master network and Stanford Method for Persistent Scatterers (StaMPS) PS-InSAR approaches. We use 32 TerraSAR-X (Track 24) radar images acquired between 2011 and 2015 from Supersites Istanbul archive provided by the German Aerospace Center (project Marmara Region Supersite, http://www.earthobservations.org/gsnl.php) and 260 ascending and descending Sentinel 1A/B TOPS images (Track 58 [Asc], 160 [Asc] and 138 [Dsc]) spanning the period from October 2014 until July 2017. Together with InSAR data, measurements from a campaign type GPS network of 35 benchmarks we established in 2013 are also used in analyzing spatial distribution of horizontal creep rate. Our GPS and Persistent Scatterer InSAR (PSI) measurements over the period of past 5 years show that afterslip on the central segment of 1999 Izmit fault rupture is still taking place since the earthquake at an average rate of about 6 mm/year, becoming the longest (i.e. 18 years) recorded afterslip. Decaying logarithmically with time, afterslip appears to have reached a steady rate comparable to the pre- earthquake full fault-crossing rate, suggesting that it may continue for decades and possibly until late in the earthquake cycle. In addition to the stable steady state creep, PS time series reveal at least two transient creep events (creep bursts) in August 2015 and December 2016. Vertical velocity field obtained with decomposition of velocity fields on ascending and descending tracks reveals persistent subsidence on the hangingwall block of the Golcuk fault. It is not clear however if this oblique normal fault in a releasing step over is also creeping or acting as a boundary to local subsidence (supported by TUBITAK 1001 project no:113Y102).

Non-consumable anode and lining for aluminum electrolytic reduction cell

DOEpatents

Beck, Theodore R.; Brooks, Richard J.

1994-01-01

An oxidation resistant, non-consumable anode, for use in the electrolytic reduction of alumina to aluminum, has a composition comprising copper, nickel and iron. The anode is part of an electrolytic reduction cell comprising a vessel having an interior lined with metal which has the same composition as the anode. The electrolyte is preferably composed of a eutectic of AlF.sub.3 and either (a) NaF or (b) primarily NaF with some of the NaF replaced by an equivalent molar amount of KF or KF and LiF.

75 FR 45557 - Prevailing Rate Systems; Definition of Tulsa County, OK, and Angelina County, TX, to...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-03

.... Veterans Canteen Service (VCS) now operates franchise coffee bars, staffed with NAF employees, at..., Government employees, Reporting and recordkeeping requirements, Wages. U.S. Office of Personnel Management...

Cancer-Related NEET Proteins Transfer 2Fe-2S Clusters to Anamorsin, a Protein Required for Cytosolic Iron-Sulfur Cluster Biogenesis.

PubMed

Lipper, Colin H; Paddock, Mark L; Onuchic, José N; Mittler, Ron; Nechushtai, Rachel; Jennings, Patricia A

2015-01-01

Iron-sulfur cluster biogenesis is executed by distinct protein assembly systems. Mammals have two systems, the mitochondrial Fe-S cluster assembly system (ISC) and the cytosolic assembly system (CIA), that are connected by an unknown mechanism. The human members of the NEET family of 2Fe-2S proteins, nutrient-deprivation autophagy factor-1 (NAF-1) and mitoNEET (mNT), are located at the interface between the mitochondria and the cytosol. These proteins have been implicated in cancer cell proliferation, and they can transfer their 2Fe-2S clusters to a standard apo-acceptor protein. Here we report the first physiological 2Fe-2S cluster acceptor for both NEET proteins as human Anamorsin (also known as cytokine induced apoptosis inhibitor-1; CIAPIN-1). Anamorsin is an electron transfer protein containing two iron-sulfur cluster-binding sites that is required for cytosolic Fe-S cluster assembly. We show, using UV-Vis spectroscopy, that both NAF-1 and mNT can transfer their 2Fe-2S clusters to apo-Anamorsin with second order rate constants similar to those of other known human 2Fe-2S transfer proteins. A direct protein-protein interaction of the NEET proteins with apo-Anamorsin was detected using biolayer interferometry. Furthermore, electrospray mass spectrometry of holo-Anamorsin prepared by cluster transfer shows that it receives both of its 2Fe-2S clusters from the NEETs. We propose that mNT and NAF-1 can provide parallel routes connecting the mitochondrial ISC system and the CIA. 2Fe-2S clusters assembled in the mitochondria are received by NEET proteins and when needed transferred to Anamorsin, activating the CIA.

Determination of Seismic Activity on the Main Marmara Fault with GPS Measurements

NASA Astrophysics Data System (ADS)

Alkan, M. N.; Alkan, R. M.; Yavaşoğlu, H.; Köse, Z.; Aladoğan, K.; Özbey, V.

2017-12-01

The tectonic plates that creates the Earth have always been an important topic to work on for Geosciences. Plate motion affecting the Earth's crust have occurred for millions of years. This slow but continuous movement that has been going on for millions of years can only be followed by instrumental measurements. In recent years, this process has been done with GPS very accurately. The North Anatolian Fault (NAF) is a major right-lateral, strike-slip fault that extends more than 1200 km extends along all North Anatolia from Bingol to Saros Gulf. The NAFZ is divided into Southern and Northern Branches to the east of Marmara region that several destructive earthquakes occurred, such as Izmit (in 1999, Mw=7.4) and Duzce (in 1999, Mw=7.2) in the last century. MMF (Main Marmara Fault) which is the part of the Northern Branch in the Marmara Sea, starting in from the Gulf of Izmit-Adapazarı and reaching the Gulf of Saros. The determination of the deformation accumulated on the MMF has become extremely important especially after the 1999 Izmit earthquake. According to the recent studies, the MMF is the largest unbroken part of the fault and is divided into segments. These segments are Cinarcik, Prince Island, Central Marmara and Tekirdag. Recent studies have demonstrated that the Prince Island segment is fully locked. However, studies that are focused on the Central Marmara segment, that is located offshore Istanbul, a giant metropole that has more than 14 million populations, do not conclude about the presence of a seismic gap, capable of generating a big earthquake. Therefore, in the scope of this study, a new GPS network was established at short and long distance from the Main Marmara Fault, to densify the existing GPS network. 3 campaign GPS measurements were done in 2015, 2016, 2017. The evaluation of the datasets were done by GAMIT/GLOBK software. For the evaluation, 30 continuous observation stations, 14 stations connected to the IGS network and 16 stations connected to the local networks CORS-TR and ISKI-UKBS, and 18 campaign stations that located in the study area were used. The evaluation was made between 12-26 August for each year and thus intended to determine the kinematics of the Main Marmara Fault.

Fluorine-18 NaF PET imaging of child abuse.

PubMed

Drubach, Laura A; Sapp, Mark V; Laffin, Stephen; Kleinman, Paul K

2008-07-01

We describe the use of 18F-NaF positron emission tomography (PET) whole-body imaging for the evaluation of skeletal trauma in a case of suspected child abuse. To our knowledge, 18F NaF PET has not been used in the past for the evaluation of child abuse. In our patient, this technique detected all sites of trauma shown by initial and follow-up skeletal surveys, including bilateral metaphyseal fractures of the proximal humeri. Fluorine-18 NaF PET has potential advantage over Tc-99m-labeled methylene diphosphonate (MDP) based upon superior image contrast and spatial resolution.

Identification of the need for home visiting nurse: development of a new assessment tool

PubMed Central

Taguchi, Atsuko; Nagata, Satoko; Naruse, Takashi; Kuwahara, Yuki; Yamaguchi, Takuhiro; Murashima, Sachiyo

2014-01-01

Objective To develop a Home Visiting Nursing Service Need Assessment Form (HVNS-NAF) to standardize the decision about the need for home visiting nursing service. Methods The sample consisted of older adults who had received coordinated services by care managers. We defined the need for home visiting nursing service by elderly individuals as the decision of the need by a care manager so that the elderly can continue to live independently. Explanatory variables included demographic factors, medical procedure, severity of illness, and caregiver variables. Multiple logistic regression was carried out after univariate analyses to decide the variables to include and the weight of each variable in the HVNS-NAF. We then calculated the sensitivity and specificity of each cutoff value, and defined the score with the highest sensitivity and specificity as the cutoff value. Results Nineteen items were included in the final HVNS-NAF. When the cutoff value was 2 points, the sensitivity was 77.0%, specificity 68.5%, and positive predictive value 56.8%. Conclusions HVNS-NAF is the first validated standard based on characteristics of elderly clients who required home visiting nursing service. Using the HVNS-NAF may result in reducing the unmet need for home visiting nursing service and preventing hospitalization. PMID:24665229

78 FR 60182 - Prevailing Rate Systems; Definition of Broward County, Florida, to a Nonappropriated Fund Federal...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-01

... OFFICE OF PERSONNEL MANAGEMENT 5 CFR Part 532 RIN 3206-AM83 Prevailing Rate Systems; Definition of..., nonappropriated fund (NAF) Federal Wage System (FWS) wage area. This change is necessary because there are three... Beach * * * * * [FR Doc. 2013-23867 Filed 9-30-13; 8:45 am] BILLING CODE 6325-39-P ...

Microtremor Array Measurement Survey and Strong Ground Motion Observation Activities of The MarDiM (SATREPS) Project

NASA Astrophysics Data System (ADS)

Ozgur Citak, Seckin; Karagoz, Ozlem; Chimoto, Kosuke; Ozel, Oguz; Yamanaka, Hiroaki; Aksahin, Bengi; Arslan, Safa; Hatayama, Ken; Ohori, Michihiro; Hori, Muneo

2015-04-01

Since 1939, devastating earthquakes with magnitude greater than seven ruptured North Anatolian Fault (NAF) westward, starting from 1939 Erzincan (Ms=7.9) at the eastern Turkey and including the latest 1999 Izmit-Golcuk (Ms=7.4) and the Duzce (Ms=7.2) earthquakes in the eastern Marmara region, Turkey. On the other hand, the west of the Sea of Marmara an Mw7.4 earthquake ruptured the NAF' s Ganos segment in 1912. The only un-ruptured segments of the NAF in the last century are within the Sea of Marmara, and are identified as a "seismic gap" zone that its rupture may cause a devastating earthquake. In order to unravel the seismic risks of the Marmara region a comprehensive multidisciplinary research project The MarDiM project "Earthquake And Tsunami Disaster Mitigation in The Marmara Region and Disaster Education in Turkey", has already been started since 2003. The project is conducted in the framework of "Science and Technology Research Partnership for Sustainable Development (SATREPS)" sponsored by Japan Science and Technology Agency (JST) and Japan International Cooperation Agency (JICA). One of the main research field of the project is "Seismic characterization and damage prediction" which aims to improve the prediction accuracy of the estimation of the damages induced by strong ground motions and tsunamis based on reliable source parameters, detailed deep and shallow velocity structure and building data. As for detailed deep and shallow velocity structure microtremor array measurement surveys were conducted in Zeytinburnu district of Istanbul and Tekirdag province at about 81 sites on October 2013 and September 2014. Also in September 2014, 11 accelerometer units were installed mainly in public buildings in both Zeytinburnu and Tekirdag area and are currently in operation. Each accelerometer unit compose of a Network Sensor (CV-374A2) by Tokyo Sokushin, post processing PC for data storage and power supply unit. The Network Sensor (CV-374A2) consist of three servo type accelerometers for two horizontal and one vertical component combined with 24 bit AD converter. In the presentation current achievements and activities of research group, preliminary results of microtremor array measurement surveys and recorded data by the newly installed stations will be introduced.

Microtremor Array Measurement Survey and Strong Ground Motion observation activities of The SATREPS, MarDiM project -Part 2-

NASA Astrophysics Data System (ADS)

Citak, Seckin; Karagoz, Ozlem; Chimoto, Kosuke; Ozel, Oguz; Yamanaka, Hiroaki; Arslan, Safa; Aksahin, Bengi; Hatayama, Ken; Ohori, Michihiro; Hori, Muneo

2016-04-01

Since 1939, devastating earthquakes with magnitude greater than seven ruptured North Anatolian Fault (NAF) westward, starting from 1939 Erzincan (Ms=7.9) at the eastern Turkey and including the latest 1999 Izmit-Golcuk (Ms=7.4) and the Duzce (Ms=7.2) earthquakes in the eastern Marmara region, Turkey. On the other hand, the west of the Sea of Marmara an Mw7.4 earthquake ruptured the NAF' s Ganos segment in 1912. The only un-ruptured segments of the NAF in the last century are within the Sea of Marmara, and are identified as a "seismic gap" zone that its rupture may cause a devastating earthquake. In order to unravel the seismic risks of the Marmara region a comprehensive multidisciplinary research project The MarDiM project "Earthquake And Tsunami Disaster Mitigation in The Marmara Region and Disaster Education in Turkey", has already been started since 2003. The project is conducted in the framework of "Science and Technology Research Partnership for Sustainable Development (SATREPS)" sponsored by Japan Science and Technology Agency (JST) and Japan International Cooperation Agency (JICA). One of the main research field of the project is "Seismic characterization and damage prediction" which aims to improve the prediction accuracy of the estimation of the damages induced by strong ground motions and tsunamis based on reliable source parameters, detailed deep and shallow velocity structure and building data. As for detailed deep and shallow velocity structure microtremor array measurement surveys were conducted in Zeytinburnu district of Istanbul, Tekirdag, Canakkale and Edirne provinces at about 109 sites on October 2013, September 2014 and 2015. Also in September 2014, 11 accelerometer units were installed mainly in public buildings in both Zeytinburnu and Tekirdag area and are currently in operation. Each accelerometer unit compose of a Network Sensor (CV-374A) by Tokyo Sokushin, post processing PC for data storage and power supply unit. The Network Sensor (CV-374A) consist of three servo type accelerometers for two horizontal and one vertical component combined with 24 bit AD converter. In the presentation current achievements and activities of research group, preliminary results of microtremor array measurement surveys and recorded data by the newly installed stations will be introduced.

Microtremor Array Measurement Survey and Strong Ground Motion observation activities of The SATREPS, MarDiM project -Part 3-

NASA Astrophysics Data System (ADS)

Citak, Seckin; Safa Arslan, Mehmet; Karagoz, Ozlem; Chimoto, Kosuke; Ozel, Oguz; Yamanaka, Hiroaki; Behiye Aksahin, Bengi; Hatayama, Ken; Sahin, Abdurrahman; Ohori, Michihiro; Safak, Erdal; Hori, Muneo

2017-04-01

Since 1939, devastating earthquakes with magnitude greater than seven ruptured North Anatolian Fault (NAF) westward, starting from 1939 Erzincan (Ms=7.9) at the eastern Turkey and including the latest 1999 Izmit-Golcuk (Ms=7.4) and the Duzce (Ms=7.2) earthquakes in the eastern Marmara region, Turkey. On the other hand, the west of the Sea of Marmara an Mw7.4 earthquake ruptured the NAF' s Ganos segment in 1912. The only un-ruptured segments of the NAF in the last century are within the Sea of Marmara, and are identified as a "seismic gap" zone that its rupture may cause a devastating earthquake. In order to unravel the seismic risks of the Marmara region a comprehensive multidisciplinary research project The MarDiM project "Earthquake And Tsunami Disaster Mitigation in The Marmara Region and Disaster Education in Turkey", has already been started since 2003. The project is conducted in the framework of "Science and Technology Research Partnership for Sustainable Development (SATREPS)" sponsored by Japan Science and Technology Agency (JST) and Japan International Cooperation Agency (JICA). One of the main research field of the project is "Seismic characterization and damage prediction" which aims to improve the prediction accuracy of the estimation of the damages induced by strong ground motions and tsunamis based on reliable source parameters, detailed deep and shallow velocity structure and building data. As for detailed deep and shallow velocity structure microtremor array measurement surveys were conducted in Zeytinburnu district of Istanbul, Tekirdag, Canakkale and Edirne provinces at about 140 sites on October 2013, September 2014, 2015 and 2016. Also in September 2014, 11 accelerometer units were installed mainly in public buildings in both Zeytinburnu and Tekirdag area and are currently in operation. Each accelerometer unit compose of a Network Sensor (CV-374A) by Tokyo Sokushin, post processing PC for data storage and power supply unit. The Network Sensor (CV-374A) consist of three servo type accelerometers for two horizontal and one vertical component combined with 24 bit AD converter. In the presentation current achievements and activities of research group, preliminary results of microtremor array measurement surveys and recorded data by the newly installed stations will be introduced.

Association between fundus autofluorescence and visual outcome in surgically closed macular holes.

PubMed

Lee, Young Seob; Yu, Seung-Young; Cho, Nam Suk; Kim, Moo Sang; Kim, Young Gyun; Kim, Eung Suk; Kwak, Hyung Woo

2013-06-01

To investigate the association between fundus autofluorescence (FAF) and visual acuity, recovery of foveal microstructure, and FAF in surgically closed macular holes. Twenty-six eyes with surgically closed macular hole were classified into two groups based on foveal FAF: normal autofluorescence (NAF) or increased autofluorescence (IAF). The association between foveal FAF and visual acuity was analyzed. In addition, we examined the relationship between recovery of the foveal microstructure assessed by spectral domain optical coherence tomography and FAF after macular hole surgery. At 1 month and 6 months after surgery, there were 9 NAF eyes and 17 IAF eyes. There were no differences between NAF and IAF eyes at 1 month and 6 months after surgery. Preoperative best-corrected visual acuity (logarithm of the minimum angle of resolution) did not differ between groups. Best-corrected visual acuity was significantly higher in the NAF group than in the IAF group at 1 month postoperatively (0.59 ± 0.34 vs. 0.91 ± 0.36, P = 0.044) and tended to be higher at 6 months (0.37 ± 0.38 vs. 0.69 ± 0.53, P = 0.126). Restoration of photoreceptor external limiting membrane differed significantly in 8 NAF eyes (89%) and 4 IAF eyes (24%) at postoperation 1 month (P = 0.001). After 6 months, external limiting membrane was restored in all 9 NAF eyes (100%) and in only 11 IAF eyes (65%) (P = 0.042). Fundus autofluorescence findings observed in surgically closed macular holes correlated with visual improvement and photoreceptor status. Eyes with visual improvement had restoration of normal foveal autofluorescence and retinal microstructure, whereas eyes with persistent foveal hyperautofluorescence did not achieve complete restoration of the retinal microstructure, and visual improvement was not as significant.

Body Fat Distribution Ratios and Obstructive Sleep Apnea Severity in Youth With Obesity.

PubMed

Glicksman, Amy; Hadjiyannakis, Stasia; Barrowman, Nicholas; Walker, Scott; Hoey, Lynda; Katz, Sherri Lynne

2017-04-15

Obesity and regional fat distribution, measured by neck fat mass percentage using dual-energy X-ray absorptiometry (DXA), correlate with obstructive sleep apnea (OSA) severity in adults. In obese children, neck-to-waist-circumference ratio predicts OSA. This study examined associations between body fat percentage and distribution and sleep-disordered breathing (SDB) severity in obese youth, measured with DXA. Cross-sectional retrospective study conducted at a tertiary children's hospital. Participants were aged 6 to 18 years with obesity (body mass index [BMI] > 99th percentile [BMI z-score 2.35] or > 95th percentile with comorbidity). They underwent polysomnography and DXA to quantify body fat percentage and distribution ratios (neck-to-abdominal fat percentage [NAF % ratio]). SDB was defined as apnea-hypopnea index (AHI) > 5 and OSA as obstructive AHI (OAHI) > 1 event/h. Relationships of BMI z-score and NAF % ratio to log AHI and log OAHI were evaluated. Thirty individuals participated; 18 male; median age 14.1 years. Twenty-four individuals had BMI z-scores > 2.35. Ten had AHI > 5 events/h. NAF % ratio was significantly associated with log AHI in males and with log OAHI in all, whereas total fat mass percent was not. The association between log OAHI and NAF % ratio was significant in males, but not females. NAF % ratio was significantly associated with log OAHI in those with BMI z-score above 2.35. NAF % ratio was associated with OSA severity in males and youth with BMI > 99th percentile; however, total fat mass percentage was not, suggesting that body fat distribution is associated with OSA risk in youth. © 2017 American Academy of Sleep Medicine

Methodological considerations in estrogen assays of breast fluid and breast tissue.

PubMed

Chatterton, Robert T; Muzzio, Miguel; Heinz, Richard; Gann, Peter H; Khan, Seema A

2015-07-01

Estradiol (E2) in nipple aspirate fluid (NAF), ductal lavage fluid (DLF), and random fine needle aspirates (rFNA) are compared. Quantification was by immunoassay or tandem MS. The percent of women yielding NAF varied between 24% and 48% and for DLF was 86.3%. Variation between ducts within a breast was not less than variation between breasts within women but variation between breasts and within women over time was significantly less than variation between women. Serum E2 was highly significantly different among phases of the menstrual cycle but NAF E2 was not different. The correlation between serum and breast fluid E2 concentrations in premenopausal women had coefficients of determination of less than 15%. The correlation between serum and NAF in studies of postmenopausal women varied greatly and may depend on patient selection. The difference between NAF E2 between pre- and postmenopausal women was only 22%; for rFNA it was non-significantly 44% lower in a similar group of postmenopausal women. Progesterone was 96% and 98% lower in postmenopausal NAF and rFNA samples, respectively. Measurements of E2 in breast fluid or breast tissue appears to provide similar estimates of E2 exposure. E2 levels in breast fluid do not reflect the rapid changes that occur in serum and, thus, serum availability of E2 is only one factor determining its levels in the breast. The similarity of levels between breasts and between ducts suggests that estimates of estrogen exposure does not require multiple samples, however, unavailability of fluid may require rFNA in some cases. Copyright © 2014 Elsevier Inc. All rights reserved.

In situ evaluation of low-fluoride toothpastes associated to calcium glycerophosphate on enamel remineralization.

PubMed

Zaze, A C S F; Dias, A P; Amaral, J G; Miyasaki, M L; Sassaki, K T; Delbem, A C B

2014-12-01

This study aimed to evaluate the effect of low-fluoride toothpastes with calcium glycerophosphate (CaGP) on enamel remineralization in situ. Volunteers (n=10) wore palatal devices holding four bovine enamel blocks. The treatments involved 5 experimental phases of 3 days each according to the following toothpastes: placebo, 500 ppm F (500 NaF), 500 ppm F with 0.25% CaGP (500 NaF CaGP), 500 ppm F with 0.25% CaGP (500 MFP CaGP) and 1100 ppm F (1100; positive control). After this experimental period, the fluoride, calcium, and phosphorus ion concentrations from enamel were determined. Surface and cross-sectional hardness were also performed. Data were analysed by 1-way ANOVA, Student-Newman-Keuls' test and by Pearson's correlation. The addition of 0.25% CaGP improved the remineralization potential of low-fluoride toothpastes and the NaF as source of fluoride yielded the best results (p<0.001) as evidenced by the hardness analysis. The 1100 ppm F toothpaste provided higher presence of fluoride in the enamel after remineralization (p<0.001). The addition of CaGP to the NaF and MFP toothpastes led to similar calcium concentration in the enamel as the observed with the positive control (p=0.054). Toothpastes with 500 ppm F (NaF or MFP) and CaGP showed similar remineralization potential than 1100 ppm F toothpaste. Toothpastes containing 500 ppm F associated to CaGP, with both fluoride source (NaF or MFP), showed a potential of remineralization similar to commercial toothpaste. Although there is a need for confirmation in the clinical setting, these results point to an alternative for improving the risk-benefit relationship between fluorosis and dental caries in small children. Copyright © 2014 Elsevier Ltd. All rights reserved.

Reciprocal changes in gene expression profiles of cocultured breast epithelial cells and primary fibroblasts.

PubMed

Rozenchan, Patricia Bortman; Carraro, Dirce Maria; Brentani, Helena; de Carvalho Mota, Louise Danielle; Bastos, Elen Pereira; e Ferreira, Elisa Napolitano; Torres, Cesar H; Katayama, Maria Lúcia Hirata; Roela, Rosimeire Aparecida; Lyra, Eduardo C; Soares, Fernando Augusto; Folgueira, Maria Aparecida Azevedo Koike; Góes, João Carlos Guedes Sampaio; Brentani, Maria Mitzi

2009-12-15

The importance of epithelial-stroma interaction in normal breast development and tumor progression has been recognized. To identify genes that were regulated by these reciprocal interactions, we cocultured a nonmalignant (MCF10A) and a breast cancer derived (MDA-MB231) basal cell lines, with fibroblasts isolated from breast benign-disease adjacent tissues (NAF) or with carcinoma-associated fibroblasts (CAF), in a transwell system. Gene expression profiles of each coculture pair were compared with the correspondent monocultures, using a customized microarray. Contrariwise to large alterations in epithelial cells genomic profiles, fibroblasts were less affected. In MDA-MB231 highly represented genes downregulated by CAF derived factors coded for proteins important for the specificity of vectorial transport between ER and golgi, possibly affecting cell polarity whereas the response of MCF10A comprised an induction of genes coding for stress responsive proteins, representing a prosurvival effect. While NAF downregulated genes encoding proteins associated to glycolipid and fatty acid biosynthesis in MDA-MB231, potentially affecting membrane biogenesis, in MCF10A, genes critical for growth control and adhesion were altered. NAFs responded to coculture with MDA-MB231 by a decrease in the expression of genes induced by TGFbeta1 and associated to motility. However, there was little change in NAFs gene expression profile influenced by MCF10A. CAFs responded to the presence of both epithelial cells inducing genes implicated in cell proliferation. Our data indicate that interactions between breast fibroblasts and basal epithelial cells resulted in alterations in the genomic profiles of both cell types which may help to clarify some aspects of this heterotypic signaling. Copyright (c) 2009 UICC.

Differential effect of N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) on (/sup 3/H)SCH23390 and (/sup numberH/)forskolin binding in rat striatum

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

Norman, A.B.; Wachendorf, T.J.; Sanberg, P.R.

1989-01-01

The binding of (/sup 3/H)forskolin to a homogeneous population of binding sites in rat striatum was enhanced by NaF, guanine nucleotides and MgCl/sub 2/. These effects of NaF and guanylylimidodiphosphate (Gpp(NH)p) were synergistic with MgCl/sub 2/, but NaF and Gpp(NH)p together elicited no greater enhancement of (/sup 3/H)forskolin binding. These data suggest that (/sup 3/H)forskolin may label a site which is modulated by the guanine nucleotide regulatory subunit which mediates the stimulation of adenylate cyclase (N/sub S/). The D/sub 1/ dopamine receptor is known to stimulate adenylate cyclase via N/sub S/. In rat striatum, the B/sub max/ of (/sup 3/H)forskolinmore » binding sites in the presence of MgCl/sub 2/ and NaF was approximately two fold greater than the B/sub max/ of (/sup 3/H)SCH23390-labeled D/sub 1/ dopamine receptors. Incubation of striatal homogenates with the protein modifying reagent EEDQ elicited a concentration-dependent decrease in the binding of both (/sup 3/H)SCH23390 and (/sup 3/H)forskolin, although EEDQ was approximately 14 fold more potent at inactivating the D/sub 1/ dopamine receptor. Following in vivo administration of EEDQ there was no significant effect on (/sup 3/H)forskolin binding sites using a dose of EEDQ that irreversibly inactivated greater than 90% of D/sub 1/ dopamine receptors. These data suggest that EEDQ is a suitable tool for investigating changes in the stoichiometry of receptors and their second messenger systems.« less

Comparison of the toxicity of fluoridation compounds in the nematode Caenorhabditis elegans.

PubMed

Rice, Julie R; Boyd, Windy A; Chandra, Dave; Smith, Marjolein V; Den Besten, Pamela K; Freedman, Jonathan H

2014-01-01

Fluorides are commonly added to drinking water in the United States to decrease the incidence of dental caries. Silicofluorides, such as sodium hexafluorosilicate (Na2 SiF6 ) and fluorosilicic acid (H2 SiF6 ), are mainly used for fluoridation, although fluoride salts such as sodium fluoride (NaF) are also used. Interestingly, only the toxicity of NaF has been examined and not that of the more often used silicofluorides. In the present study, the toxicities of NaF, Na2 SiF6 , and H2 SiF6 were compared. The toxicity of these fluorides on the growth, feeding, and reproduction in the alternative toxicological testing organism Caenorhabditis elegans was examined. Exposure to these compounds produced classic concentration-response toxicity profiles. Although the effects of the fluoride compounds varied among the 3 biological endpoints, no differences were found between the 3 compounds, relative to the fluoride ion concentration, in any of the assays. This suggests that silicofluorides have similar toxicity to NaF. © 2013 SETAC.

Altered sperm chromatin structure in mice exposed to sodium fluoride through drinking water.

PubMed

Sun, Zilong; Niu, Ruiyan; Wang, Bin; Wang, Jundong

2014-06-01

This study investigated the effects of sodium fluoride (NaF) on sperm abnormality, sperm chromatin structure, protamine 1 and protamine 2 (P1 and P2) mRNA expression, and histones expression in sperm in male mice. NaF was orally administrated to male mice at 30, 70, and 150 mg/l for 49 days (more than one spermatogenic cycle). Sperm head and tail abnormalities were significantly enhanced at middle and high doses. Similarly, sperm chromatin structure was also adversely affected by NaF exposure, indicating DNA integrity damage. Furthermore, middle and high NaF significantly reduced the mRNA expressions of P1 and P2, and P1/P2 ratio, whereas the sperm histones level was increased, suggesting the abnormal histone-protamine replacement. Therefore, we concluded that the mechanism by which F induced mice sperm abnormality and DNA integrity damage may involved in the alterations in P1, P2, and histones expression in sperm of mice. Copyright © 2012 Wiley Periodicals, Inc.

Long-term effect of diode laser irradiation compared to sodium fluoride varnish in the treatment of dentine hypersensitivity in periodontal maintenance patients: a randomized controlled clinical study.

PubMed

Yilmaz, Hasan Guney; Kurtulmus-Yilmaz, Sevcan; Cengiz, Esra

2011-11-01

The aim of this clinical study was to evaluate and compare the desensitizing effects of a gallium?aluminum?arsenide (GaAlAs) laser and sodium fluoride (NaF) varnish on dentine hypersensitivity (DH) in periodontal maintenance patients. The use of lasers opens a new dimension in the treatment of DH. Forty-eight patients with 244 teeth affected by DH were included in the trial. To be included in the study, the subjects had to have 4 or more hypersensitive teeth at different quadrants. Selected teeth were randomly assigned to a GaAlAs laser group, placebo laser group, NaF varnish group, or a placebo NaF varnish group. Laser therapy was performed at 8.5?J/cm(2) energy density. In the placebo laser group, the same laser without laser emission was used. In the NaF varnish group, the varnish was painted at the cervical region of the teeth. In the placebo NaF varnish group, the same treatment procedures were performed with a saline solution. DH was assessed with a visual analog scale (VAS); immediately, at 1 week, and at 1, 3, and 6 months after treatments. Intra-group time-dependent data were analyzed by Friedman's test, and Wilcoxon's rank sum test was used to evaluate the differences within groups. GaAlAs laser and NaF varnish treatments resulted in a significant reduction in the VAS scores immediately after treatments that were maintained throughout the study when compared to the baseline and placebo treatments. In the NaF group, there was a significant increase in the VAS scores at 3 and 6 months compared to at 1 week and 1 month. The placebo treatments showed no significant changes in VAS scores throughout the study period. Within the limits of the study, GaAlAs laser irradiation was effective in the treatment of DH, and it is a more comfortable and faster procedure than traditional DH treatment.

Diversity and function of the Antarctic krill microorganisms from Euphausia superba

NASA Astrophysics Data System (ADS)

Cui, Xiaoqiu; Zhu, Guoliang; Liu, Haishan; Jiang, Guoliang; Wang, Yi; Zhu, Weiming

2016-11-01

The diversity and ecological function of microorganisms associated with Euphausia superba, still remain unknown. This study identified 75 microbial isolates from E. superba, that is 42 fungi and 33 bacteria including eight actinobacteria. And all the isolates showed NaF tolerance in conformity with the nature of the fluoride krill. The maximum concentration was 10%, 3% and 0.5% NaF for actinobacteria, bacteria and fungi, respectively. The results demonstrated that 82.4% bacteria, 81.3% actinobacteria and 12.3% fungi produced antibacterial metabolites against pathogenic bacteria without NaF; the MIC value reached to 3.9 μg/mL. In addition, more than 60% fungi produced cytotoxic metabolites against A549, MCF-7 or K562 cell lines. The presence of NaF led to a reduction in the producing antimicrobial compounds, but stimulated the production of cytotoxic compounds. Furthermore, seven cytotoxic compounds were identified from the metabolites of Penicillium citrinum OUCMDZ4136 under 0.5% NaF, with the IC50 values of 3.6-13.1 μM for MCF-7, 2.2-19.8 μM for A549 and 5.4-15.4 μM for K562, respectively. These results indicated that the krill microbes exert their chemical defense by producing cytotoxic compounds to the mammalians and antibacterial compounds to inhibiting the pathogenic bacteria.

77 FR 47852 - Agency Information Collection Activities: Proposed Collection; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-10

... Beneficiaries Receiving NaF-18 Positron Emission Tomography (PET) to Identify Bone Metastasis in Cancer; Use: In... NaF-18 PET scan to identify bone metastasis in cancer is reasonable and necessary only when the... strategy by the identification, location and quantification of bone [[Page 47853

Estimation of the long-term slip, surface uplift and block rotation along the northern strand of the North Anatolian Fault Zone: Inferences from geomorphology of the Almacık Block

NASA Astrophysics Data System (ADS)

Yıldırım, Cengiz; Tüysüz, Okan

2017-11-01

The Almacık Block is one of the key morphotectonic units in the eastern Marmara Region associated with the long-term slip partitioning within the North Anatolian Fault Zone (NAFZ). In this study, we provide new geomorphic reconstructions of offset drainage basins, morphometric analysis of topography, and longitudinal profiles of the rivers crossing different flanks of the Almacık Block. Our geomorphic reconstructions of offset drainage basins along the Hendek and Karadere faults imply mean offsets of 2.3 ± 0.4 km and 8.4 ± 0.7 km, respectively, during the Quaternary. Our dataset also imply that slip partitioning occurs in a broader zone than previously proposed, and that the total 10.7 ± 0.6 km offset along the Hendek and Karadere faults of the northern strand must be taken into account for long-term slip partitioning in the Eastern Marmara Region. Together with previously suggested 10 km offset along the southern strand (Yaltırak, 2002), 16 ± 1.0 km offset along the middle strand (Özalp et al., 2013) and the 52 ± 1.0 km offset along the Mudurnu Segment of the northern strand (Akbayram et al., 2016) our newly proposed geomorphic markers raise the cumulative offset in the eastern Marmara region associated with the NAF to 89 ± 1.0 km since the Latest Pliocene - Quaternary. In addition to these lateral displacements, our morphometric analysis and longitudinal profiles of the rivers imply up to 1130 ± 130 m surface uplift of the Almacık Block as a combined result of vertical displacement within the deformation zone of the northern strand of the NAFZ. Finally, by assuming that river basins act as passive deformation markers, our basin azimuth analyses imply 20° ± 2° clockwise rotation of the Almacık Block associated with the NAFZ.

Analysis of micro-seismicity and gas emissions along the North-Anatolian Fault within the Sea of Marmara

NASA Astrophysics Data System (ADS)

Evangelia, B.; Géli, L.; Lomax, A.; Henry, P.; Tary, J. B.; Klingelhoefer, F.; Gurbuz, C.; Monna, S.; Bayrakci, G.

2016-12-01

The Marmara-Istanbul region, along the North-Anatolian Fault (NAF), is generally considered to be within a seismic gap, with the potential of an impending earthquake of magnitude > 7. The determination of the mechanical behavior of the submarine segments in the Sea of Marmara is of utmost importance for seismic hazard assessment. Seismic catalogs for the period 2007-2012 (e.g. Schmittbuhl et al., 2015) show that earthquakes of magnitude > 4.5 in the Western Sea of Marmara are systematically located where gas emissions have been found and followed by swarms of aftershocks which appear to be vertically distributed from the base of the crust to the sediment surface. These observations suggest that there is a possible relation between the presence of gas and the occurrence of shallow seismicity (< 4 km). To test this hypotheses, a detailed analysis of the micro-seismicity recorded by Ocean Bottom Seismometers (OBSs) in 2011 and 2014, was performed, using a 3D high resolution velocity model. Due to an insufficient station coverage in the immediate vicinity of the fault, locations are subject to ambiguity, from the base of the crust to the surface. The results however confirm the presence of shallow (< 4 km) aftershock sequences in relation to gas emissions. Considering 1) that, following Schmittbuhl et al (2015), the western segment of the MMF is creeping; and 2) that, following Sakic et al (2016), the central segment -where no gas emissions are observed- is locked; it has been proposed that a causal relation exists between i) creeping at crustal levels; ii) increase in sediment permeability within the fault zone; and iii) gas emissions. In addition, we here propose that the crustal creep-related seismicity may in some cases also induce shallow seismicity and enhance gas emissions from the seafloor. Sakic et al, (2016), Geophys. Res. Let., doi/10.1002/2016GL069600 Schmittbuhl et al, (2015), Geochemistry, Geophysics, Geosystems, DOI 10.1002/2015GC006120

Effect of sodium fluoride on skeletal mass in primary osteoporosis

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

Zanzi, I.; Aloia, J.; Ellis, K.

1977-01-01

The administration of NaF plus Ca to a group of eleven patients with primary osteoporosis did not result in an increase in TBCa as measured by TBNAA or in BMC by photon absorptiometry. However, the group of osteoporotic patients receiving Ca alone differed significantly from the group receiving NaF, with initial increase in TBCa, although the treatment of Ca was maintained for only one year. A possible explanation for the lack of effect of NaF here and the previously reported beneficial effect may be the absence of concomitant administration of vitamin D. However, no clinical or consistent laboratory manifestation ofmore » osteomalacia were observed in the patients.« less

Speaking Personally--With Glenn Nierman

ERIC Educational Resources Information Center

Long, Joshua

2017-01-01

Dr. Glenn Nierman, current Glenn Korff Chair of Music Education at the University of Nebraska-Lincoln, is the immediate past president of the National Association for Music Education (NAfME) and a member of the board of directors of the International Society of Music Education (ISME). He has authored several journal articles, presented at NAfME…

Abnormal spermatogenesis following sodium fluoride exposure is associated with the downregulation of CREM and ACT in the mouse testis.

PubMed

Wang, Chong; Chen, Yan; Manthari, Ram Kumar; Wang, Jundong

2018-04-01

cAMP response element modulator (CREM) is involved in regulating gene expression in normal spermatogenesis. The transcriptional activity of CREM is partly regulated by activator of CREM in the testis (ACT). To investigate the effects of different concentrations of sodium fluoride (NaF) on the gene and protein expression of CREM and ACT in the mouse testis, sexually mature male Kunming mice were exposed to 50, 100, or 150 mg/L NaF in their drinking water for 90 days. NaF reduced the sperm count and viability and increased the percentage of malformed sperm in a dose-dependent manner. The mRNA expression of CREM and ACT was markedly downregulated in the NaF-treated groups. Furthermore, immunohistochemistry revealed that CREM and ACT proteins were decreased significantly in the 50, 100, and 150 mg/L NaF-treated groups compared to the control group. These findings indicate that the decreased gene and protein expression of CREM and ACT in the testis is associated with an impairment of reproductive functions by NaF.

Effective removal of the antibiotic Nafcillin from water by combining the Photoelectro-Fenton process and Anaerobic Biological Digestion.

PubMed

Vidal, Jorge; Huiliñir, Cesar; Santander, Rocío; Silva-Agredo, Javier; Torres-Palma, Ricardo A; Salazar, Ricardo

2018-05-15

The elimination of the antibiotic Nafcillin (NAF), which is usually used in hospitals and veterinary clinics around the world, was assessed through a combination of three advanced electrochemical oxidation processes followed by anaerobic digestion process. In the first stage different electrochemical advanced oxidation processes (EAOPs) were used: electro-oxidation with hydrogen peroxide (EO-H 2 O 2 ), electro-Fenton (EF) and Photo electro-Fenton (PEF). After PEF, almost complete and highly efficient degradation and elimination of NAF was achieved, with the concomitant elimination of the associated antimicrobial activity. The fast degradation rate produced by PEF is explained by the oxidative action of hydroxyl radicals (•OH) together with the direct UV photolysis of complexes formed between Fe 3+ and some organic intermediates. Total removal of NAF occurs after 90min of electrolysis by PEF, with the generation of organic intermediates that remain in solution. However, when this post PEF process solution was treated with an anaerobic biological process, the intermediates generated in the electrochemical degradation of NAF were completely eliminated after 24h. The kinetic degradation of NAF as well as the identification/quantification of products and intermediates formed during the degradation of antibiotic, such as inorganic ions, carboxylic acids and aromatic compounds, were determined by chromatographic and photometric methods. Finally, an oxidation pathway is proposed for the complete conversion to CO 2 . Copyright © 2017 Elsevier B.V. All rights reserved.

The role of the IRE1 pathway in excessive iodide- and/or fluoride-induced apoptosis in Nthy-ori 3-1 cells in vitro.

PubMed

Liu, Hongliang; Zeng, Qiang; Cui, Yushan; Zhao, Liang; Zhang, Lei; Fu, Gang; Hou, Changchun; Zhang, Shun; Yu, Linyu; Jiang, Chunyang; Wang, Zhenglun; Chen, Xuemin; Wang, Aiguo

2014-01-30

Excessive iodide and fluoride coexist in the groundwater in many regions, causing a potential risk to the human thyroid. To investigate the mechanism of iodide- and fluoride-induced thyroid cytotoxicity, human thyroid follicular epithelial cells (Nthy-ori 3-1) were treated with different concentrations of potassium iodide (KI), with or without sodium fluoride (NaF). Cell morphology, viability, lactate dehydrogenase (LDH) leakage, apoptosis, and expression of inositol-requiring enzyme 1 (IRE1) pathway-related molecules were assessed. Results showed 50 mM of KI, 1 mM of NaF, and 50 mM of KI +1 mM of NaF changed cellular morphology, decreased viability, and increased LDH leakage and apoptosis. Elevated expression of binding protein (BiP), IRE1, and C/EBP homologous protein (CHOP) mRNA and protein, as well as spliced X-box-binding protein-1 (sXBP-1) mRNA, were observed in the 1 mM NaF and 50 mM KI +1 mM NaF groups. Collectively, excessive iodide and/or fluoride is cytotoxic to the human thyroid. Although these data do not manifest iodide could induce the IRE1 pathway, the cytotoxicity followed by exposure to fluoride alone or in combination with iodide may be related to IRE1 pathway-induced apoptosis. Furthermore, exposure to the combination of excessive iodide and fluoride may cause interactive effects on thyroid cytotoxicity. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Influence of bioadhesive polymers on the protective effect of fluoride against erosion.

PubMed

Ávila, Daniele Mara da Silva; Zanatta, Rayssa Ferreira; Scaramucci, Tais; Aoki, Idalina Vieira; Torres, Carlos Rocha Gomes; Borges, Alessandra Bühler

2017-01-01

This study investigated if the incorporation of the bioadhesive polymers Carbopol 980, Carboxymethyl cellulose (CMC), and Aristoflex AVC in a fluoridated solution (NaF-900ppm) would increase the solution's protective effect against enamel erosion. Enamel specimens were submitted to a 5-day de-remineralization cycling model, consisting of 2min immersions in 0.3% citric acid (6x/day), 1min treatments with the polymers (associated or not with fluoride), and 60min storage in artificial saliva. Ultrapure water was used as the negative control and a 900ppm fluoride solution as positive control. The initial Knoop microhardness (KHN1) was used to randomize the samples into groups. Another two microhardness assessments were performed after the first (KHN2) and second (KHN3) acid immersions, to determine initial erosion in the first day. The formula: %KHN alt =[(KHN3-KHN2)/KHN2]*100 was used to define the protective effect of the treatments. After the 5-day cycling, surface loss (SL, in μm) was evaluated with profilometry. Data were analyzed with 2-way ANOVA and Tukey's tests (p<0.05). For %KHN alt , the polymers alone did not reduce enamel demineralization when compared to the negative control, but Carbopol associated with NaF significantly improved its protective effect. The profilometric analysis showed that Carbopol, associated or not with NaF, exhibited the lowest SL, while CMC and Aristoflex did not exhibit a protective effect, nor were they able to improve the protection of NaF. It is concluded that Carbopol enhanced NaF's protection against initial erosion. Carbopol alone or associated with NaF was able to reduce SL after several erosive challenges. Carbopol by itself was able to reduce the erosive wear magnitude to the same extent as the sodium fluoride, therefore, is a promising agent to prevent or control enamel erosion. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Fe-S cluster-containing NEET proteins mitoNEET and NAF-1 as chemotherapeutic targets in breast cancer.

PubMed

Bai, Fang; Morcos, Faruck; Sohn, Yang-Sung; Darash-Yahana, Merav; Rezende, Celso O; Lipper, Colin H; Paddock, Mark L; Song, Luhua; Luo, Yuting; Holt, Sarah H; Tamir, Sagi; Theodorakis, Emmanuel A; Jennings, Patricia A; Onuchic, José N; Mittler, Ron; Nechushtai, Rachel

2015-03-24

Identification of novel drug targets and chemotherapeutic agents is a high priority in the fight against cancer. Here, we report that MAD-28, a designed cluvenone (CLV) derivative, binds to and destabilizes two members of a unique class of mitochondrial and endoplasmic reticulum (ER) 2Fe-2S proteins, mitoNEET (mNT) and nutrient-deprivation autophagy factor-1 (NAF-1), recently implicated in cancer cell proliferation. Docking analysis of MAD-28 to mNT/NAF-1 revealed that in contrast to CLV, which formed a hydrogen bond network that stabilized the 2Fe-2S clusters of these proteins, MAD-28 broke the coordinative bond between the His ligand and the cluster's Fe of mNT/NAF-1. Analysis of MAD-28 performed with control (Michigan Cancer Foundation; MCF-10A) and malignant (M.D. Anderson-metastatic breast; MDA-MB-231 or MCF-7) human epithelial breast cells revealed that MAD-28 had a high specificity in the selective killing of cancer cells, without any apparent effects on normal breast cells. MAD-28 was found to target the mitochondria of cancer cells and displayed a surprising similarity in its effects to the effects of mNT/NAF-1 shRNA suppression in cancer cells, causing a decrease in respiration and mitochondrial membrane potential, as well as an increase in mitochondrial iron content and glycolysis. As expected, if the NEET proteins are targets of MAD-28, cancer cells with suppressed levels of NAF-1 or mNT were less susceptible to the drug. Taken together, our results suggest that NEET proteins are a novel class of drug targets in the chemotherapeutic treatment of breast cancer, and that MAD-28 can now be used as a template for rational drug design for NEET Fe-S cluster-destabilizing anticancer drugs.

Global Insurgency to Reestablish the Caliphate; Identifying and Understanding the Enemy

DTIC Science & Technology

2009-05-21

article&id=729: qwe -have-returned- from-the-lesser-jihad-to-the-greater-jihad-jihad-un-nafs-jihad-ul-akbarq&catid=129&Itemid=63 (accessed 31...article&id=729: qwe -have- returned-from-the-lesser-jihad-to-the-greater-jihad-jihad-un-nafs-jihad-ul- akbarq&catid=129&Itemid=63 (accessed February 18, 2009

Establishment of Antakya Basin Strong Ground Motion Monitoring System

NASA Astrophysics Data System (ADS)

Durukal, E.; Özel, O.; Bikce, M.; Geneş, M. C.; Kacın, S.; Erdik, M.; Safak, E.; Över, S.

2009-04-01

Turkey is located in one of the most active earthquake zones of the world. The cities located along the North Anatolian Fault (NAF) and the East Anatolian Fault (EAF) are exposed to significant earthquake hazard. The Hatay province near the southern terminus of the EAF has always experienced a significant seismic activity, since it is on the intersection of the northernmost segment of Dead Sea Fault Zone coming from the south, with the Cyprean Arc approaching from south-west. Historical records extending over the last 2000 years indicate that Antakya, founded in the 3rd century B.C., is effected by intensity IX-X earthquakes every 150 years. In the region, the last destructive earthquake occurred in 1872. Destructive earthquakes should be expected in the region in the near future similar to the ones that occurred in the past. The strong response of sedimentary basins to seismic waves was largely responsible for the damage produced by the devastating earthquakes of 1985 Michoacan Earthquake which severely damaged parts of Mexico City, and the 1988 Spitak Earthquake which destroyed most of Leninakan, Armenia. Much of this devastating response was explained by the conversion of seismic body waves to surface waves at the sediment/rock contacts of sedimentary basins. "Antakya Basin Strong Ground Motion Monitoring System" is set up with the aim of monitoring the earthquake response of the Antakya Basin, contributing to our understanding of basin response, contributing to earthquake risk assessment of Antakya, monitoring of regional earthquakes and determining the effects of local and regional earthquakes on the urban environment of Antakya. The soil properties beneath the strong motion stations (S-Wave velocity structure and dominant soil frequency) are determined by array measurements that involve broad-band seismometers. The strong motion monitoring system consists of six instruments installed in small buildings. The stations form a straight line along the short axis of Antakya basin passing through the city center. They are equipped with acceleration sensors, GPS and communication units and operate in continuous recording mode. For on-line data transmission the EDGE mode of available GSM systems are employed. In the array measurements for the determination of soil properties beneath the stations two 4-seismometer sets have been utilized. The system is the first monitoring installment in Turkey dedicated to understanding basin effects. The records obtained will allow for the visualization of the propagation of long-period ground motion in the basin and show the refraction of surface waves at the basin edge. The records will also serve to enhance our capacity to realistically synthesize the strong ground motion in basin-type environments.

77 FR 11383 - Prevailing Rate Systems; Abolishment of Monmouth, NJ, as a Nonappropriated Fund Federal Wage...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-27

...;Prices of new books are listed in the first FEDERAL REGISTER issue of each #0;week. #0; #0; #0; #0;#0... abolish the Monmouth, New Jersey, nonappropriated fund (NAF) Federal Wage System (FWS) wage area and... closure of Fort Monmouth left the Monmouth wage area without an activity having the capability to conduct...

System architecture of communication infrastructures for PPDR organisations

NASA Astrophysics Data System (ADS)

Müller, Wilmuth

2017-04-01

The growing number of events affecting public safety and security (PS and S) on a regional scale with potential to grow up to large scale cross border disasters puts an increased pressure on organizations responsible for PS and S. In order to respond timely and in an adequate manner to such events Public Protection and Disaster Relief (PPDR) organizations need to cooperate, align their procedures and activities, share the needed information and be interoperable. Existing PPDR/PMR technologies do not provide broadband capability, which is a major limitation in supporting new services hence new information flows and currently they have no successor. There is also no known standard that addresses interoperability of these technologies. The paper at hands provides an approach to tackle the above mentioned aspects by defining an Enterprise Architecture (EA) of PPDR organizations and a System Architecture of next generation PPDR communication networks for a variety of applications and services on broadband networks, including the ability of inter-system, inter-agency and cross-border operations. The Open Safety and Security Architecture Framework (OSSAF) provides a framework and approach to coordinate the perspectives of different types of stakeholders within a PS and S organization. It aims at bridging the silos in the chain of commands and on leveraging interoperability between PPDR organizations. The framework incorporates concepts of several mature enterprise architecture frameworks including the NATO Architecture Framework (NAF). However, OSSAF is not providing details on how NAF should be used for describing the OSSAF perspectives and views. In this contribution a mapping of the NAF elements to the OSSAF views is provided. Based on this mapping, an EA of PPDR organizations with a focus on communication infrastructure related capabilities is presented. Following the capability modeling, a system architecture for secure and interoperable communication infrastructures for PPDR organizations is presented. This architecture was implemented within a project sponsored by the European Union and successfully demonstrated in a live validation exercise in June 2016.

Study of the quaternary Na+, K+//F-, Br-, NO 3 - reciprocal system using an innovative methodology

NASA Astrophysics Data System (ADS)

Morgunova, O. E.; Ukhanov, A. S.; Katasonova, E. A.; Trunin, A. S.; Surinskii, K. D.

2016-08-01

The topological structure of the quaternary Na+, K+//F-, Br-, NO 3 - system is studied using a computer-assisted research system. A tree of phases is constructed, and the eutectic characteristics of the secant triangle NaNO3-KBr-NaF, (equiv. %) 84.6 NaNO3-9.1 KBr-6.3 NaF, at 255.3°C are determined.

Hydrogen-fluorine exchange in NaBH4-NaBF4.

PubMed

Rude, L H; Filsø, U; D'Anna, V; Spyratou, A; Richter, B; Hino, S; Zavorotynska, O; Baricco, M; Sørby, M H; Hauback, B C; Hagemann, H; Besenbacher, F; Skibsted, J; Jensen, T R

2013-11-07

Hydrogen-fluorine exchange in the NaBH4-NaBF4 system is investigated using a range of experimental methods combined with DFT calculations and a possible mechanism for the reactions is proposed. Fluorine substitution is observed using in situ synchrotron radiation powder X-ray diffraction (SR-PXD) as a new Rock salt type compound with idealized composition NaBF2H2 in the temperature range T = 200 to 215 °C. Combined use of solid-state (19)F MAS NMR, FT-IR and DFT calculations supports the formation of a BF2H2(-) complex ion, reproducing the observation of a (19)F chemical shift at -144.2 ppm, which is different from that of NaBF4 at -159.2 ppm, along with the new absorption bands observed in the IR spectra. After further heating, the fluorine substituted compound becomes X-ray amorphous and decomposes to NaF at ~310 °C. This work shows that fluorine-substituted borohydrides tend to decompose to more stable compounds, e.g. NaF and BF3 or amorphous products such as closo-boranes, e.g. Na2B12H12. The NaBH4-NaBF4 composite decomposes at lower temperatures (300 °C) compared to NaBH4 (476 °C), as observed by thermogravimetric analysis. NaBH4-NaBF4 (1:0.5) preserves 30% of the hydrogen storage capacity after three hydrogen release and uptake cycles compared to 8% for NaBH4 as measured using Sievert's method under identical conditions, but more than 50% using prolonged hydrogen absorption time. The reversible hydrogen storage capacity tends to decrease possibly due to the formation of NaF and Na2B12H12. On the other hand, the additive sodium fluoride appears to facilitate hydrogen uptake, prevent foaming, phase segregation and loss of material from the sample container for samples of NaBH4-NaF.

Efficacy of triclosan-based toothpastes in the prevention and treatment of plaque-induced periodontal and peri-implant diseases.

PubMed

Trombelli, L; Farina, R

2013-03-01

To evaluate the efficacy of triclosan (T)-based toothpaste formulations in the prevention and treatment of plaque-induced periodontal and peri-implant diseases. A review of the existing literature was conducted with a systematic approach in order to retrieve pertinent articles. i) Compared with a control fluoride dentifrice, a fluoride dentifrice containing T formulations provides a more effective level of plaque control and gingival health in patients affected by gingivitis; ii) 0.3% T/2% copolymer/0.243% NaF formulation and 0.3% T/0.13% Ca glicerophosphate/1000 ppm F toothpaste in a natural Ca carbonate base seem the most effective T-based toothpaste formulations in controlling plaque and gingival inflammation in patients with gingivitis or mild/moderate periodontitis over a 6-month period; iii) 0.3% T/2% copolymer/0.243% NaF toothpaste formulation can reduce clinical attachment loss in young adolescents when compared with a 0.243% NaF toothpaste formulation, the magnitude of the difference being greater for patients with deep periodontal pockets at baseline; iv) 0.3% T/2% copolymer/0.243% NaF toothpaste formulation is either similarly or more efficacious in preventing the progression/recurrence of periodontal destruction when compared to a conventional fluoride toothpaste; v) 0.3% T/2% copolymer/0.243% NaF toothpaste formulation seems to be more effective than a fluoride toothpaste formulation in controlling the severity of mucosal inflammation, the incidence of mucosal bleeding as well as reducing probing pocket depth around dental implants.

Fluoride exposure changed the structure and the expressions of HSP related genes in testes of pubertal rats.

PubMed

Zhao, Yangfei; Zhao, Jun; Wang, Jinming; Wang, Jundong

2017-10-01

Previous studies have indicated that fluoride exposure damaged the male reproductive function; however, the cellular mechanism of fluoride-induced testicular toxicity is still unclear. In this study, twenty-two female pregnant Wistar rats were allotted randomly to two groups: control (deionized water) and sodium fluoride (NaF, contain F - : 67.86 mg/L) groups. After delivery, the dosage was continued for 15 weeks for puppies. Twelve rats in each group were tested at 6 and 9 (pubertal); 12 and 15 (mature) weeks of age. Our results suggested that organ coefficient of epididymis was significantly decreased in the mature (12 and 15 week-old) rats. Epididymal sperm abnormality and femur fluoride concentration were increased with the concomitant decrease in sperm motility and concentration in these experimental periods. Compared to the control, in the NaF group, the seminiferous tubules of each age were reduced in terms of diameter and thickness. The sperm cells were lost and shedding and finally disappeared after 9 weeks. mRNA and protein levels of HSP27 and 90 were decreased with a concomitant increase in HSP70 and HSF mRNA and protein levels in NaF exposed rats. The mRNA and protein levels of HSP27 and HSF (only mRNA) were significantly increased in NaF treated rats at 9 and 15 weeks of age, respectively. In summary, these results emphasize that NaF induces testicular and sperm abnormalities through the involvement of HSPs especially during the pubertal period. Copyright © 2017 Elsevier Ltd. All rights reserved.

Erythrocyte metabolism in hyperthyroidism: a microcalorimetric study on changes in the Embden-Meyerhof and the hexose monophosphate pathways.

PubMed

Monti, M; Hedner, P; Ikomi-Kumm, J; Valdemarsson, S

1987-05-01

Erythrocyte metabolism was studied in vitro by microcalorimetry in 10 hyperthyroid subjects before and after treatment. By inhibiting the enzyme enolase in the Embden-Meyerhof pathway with sodium fluoride (NaF) we have recorded the anaerobic and aerobic contributions in erythrocyte thermogenesis. The decrease in heat production rate in samples with NaF corresponds to the anaerobic contribution, whereas the values from samples with NaF reflect aerobic processes. Before treatment, total heat production rate was 120 +/- 2 mW/l erythrocytes which was higher than the post-treatment value of 99 +/- 2 (P less than 0.001) as well as the value for 14 euthyroid subjects, 108 +/- 2 mW/l (P less than 0.001). The NaF inhibitable rate was 73 +/- 2 before and 63 +/- 1 mW/l after therapy (P less than 0.01). These values correspond to 61 +/- 1 and 64 +/- 1% (n.s.) of the total heat production rate, and were similar to that of 61 +/- 2% for the controls. Heat production rates in the presence of NaF were 47 +/- 1 before and 36 +/- 1 mW/l after therapy (P less than 0.001), representing 39 +/- 1 and 36 +/- 1% of total values, respectively. The present results show that overall metabolism is increased in erythrocytes from hyperthyroid subjects before treatment and returns to normal after normalization of the thyroid function. Moreover, by using microcalorimetry we found that the metabolic activity along the Embden-Meyerhof anaerobic pathway as well as along the hexose monophosphate aerobic pathway in erythrocytes is stimulated by thyroid hormones.

Formaldehyde emissions from ULEF- and NAF-bonded commercial hardwood plywood as influenced by temperature and relative humidity

Treesearch

Charles R. Frihart; James M. Wescott; Michael J. Birkeland; Kyle M. Gonner

2010-01-01

It is well documented in the literature that temperature and humidity can influence formaldehyde emissions from composite panels that are produced using urea-formaldehyde (UF) adhesives. This work investigates the effect of temperature and humidity on newer, ultra-low emitting formaldehyde urea formaldehyde (ULEF-UF) and no-added formaldehyde (NAF) adhesives. A...

Antioxidant status in oral subchronic toxicity of fipronil and fluoride co-exposure in buffalo calves.

PubMed

Gill, Kamalpreet Kaur; Dumka, Vinod Kumar

2016-02-01

The effects of fipronil and fluoride co-exposure were investigated on antioxidant status of buffalo calves. A total of 24 healthy male buffalo calves divided into 4 groups were treated for 98 consecutive days. Group I, receiving no treatment, served as the control. Animals of groups II and III were orally administered with fipronil at the dosage of 0.5 mg/kg/day and sodium fluoride (NaF) at the dosage of 6.67 mg/kg/day, respectively, for 98 days. Group IV was coadministered with fipronil and NaF at the same dosages as groups II and III. Administration of fipronil alone produced significant elevation in lipid peroxidation (LPO) and decrease in the levels of nonenzymatic antioxidant glutathione (GSH). However, it did not produce any significant effect on the activities of enzymatic antioxidants including glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD). NaF exposure led to enhanced oxidative stress as shown by significant increase in the LPO and SOD activities while GPx and CAT activities and GSH levels were significantly decreased. Co-exposure to fipronil and NaF showed additive effects on LPO, GPx activity, and GSH levels. © The Author(s) 2013.

Tacrolimus interaction with nafcillin resulting in significant decreases in tacrolimus concentrations: A case report.

PubMed

Wungwattana, Minkey; Savic, Marizela

2017-04-01

Tacrolimus (TAC) is subject to many drug interactions as a result of its metabolism primarily via CYP450 isoenzyme 3A4. Numerous case reports of TAC and CYP3A4 inducers and inhibitors have been described including antimicrobials, calcium channel antagonists, and antiepileptic drugs. We present the case of a 13-year-old patient with cystic fibrosis and a history of liver transplantation, where subtherapeutic TAC concentrations were suspected to be a result of concomitant TAC and nafcillin (NAF) therapy. The observed drug interaction occurred on two separate hospital admissions, during both of which the patient exhibited therapeutic TAC concentrations prior to exposure to NAF, a CYP3A4 inducer. Upon discontinuation of NAF, TAC concentrations recovered in both instances. This case represents a drug-drug interaction between TAC and NAF that has not previously been reported to our knowledge. Despite the lack of existing reports of interaction between these two agents, this case highlights the importance of therapeutic drug monitoring and assessing for any potential drug-drug or drug-food interactions in patients receiving TAC therapy. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Surface nano-architecture of a metal-organic framework.

PubMed

Makiura, Rie; Motoyama, Soichiro; Umemura, Yasushi; Yamanaka, Hiroaki; Sakata, Osami; Kitagawa, Hiroshi

2010-07-01

The rational assembly of ultrathin films of metal-organic frameworks (MOFs)--highly ordered microporous materials--with well-controlled growth direction and film thickness is a critical and as yet unrealized issue for enabling the use of MOFs in nanotechnological devices, such as sensors, catalysts and electrodes for fuel cells. Here we report the facile bottom-up fabrication at ambient temperature of such a perfect preferentially oriented MOF nanofilm on a solid surface (NAFS-1), consisting of metalloporphyrin building units. The construction of NAFS-1 was achieved by the unconventional integration in a modular fashion of a layer-by-layer growth technique coupled with the Langmuir-Blodgett method. NAFS-1 is endowed with highly crystalline order both in the out-of-plane and in-plane orientations to the substrate, as demonstrated by synchrotron X-ray surface crystallography. The proposed structural model incorporates metal-coordinated pyridine molecules projected from the two-dimensional sheets that allow each further layer to dock in a highly ordered interdigitated manner in the growth of NAFS-1. We expect that the versatility of the solution-based growth strategy presented here will allow the fabrication of various well-ordered MOF nanofilms, opening the way for their use in a range of important applications.

NaF-assisted combustion synthesis of MoSi2 nanoparticles and their densification behavior

NASA Astrophysics Data System (ADS)

Nersisyan, Hayk H.; Lee, Tae Hyuk; Ri, Vladislav; Lee, Jong Hyeon; Suh, Hoyoung; Kim, Jin-Gyu; Son, Hyeon Taek; Kim, Yong-Ho

2017-03-01

The exothermic reduction of oxides mixture (MoO3+2SiO2) by magnesium in NaF melt enables the synthesis of nanocrystalline MoSi2 powders in near-quantitative yields. The combustion wave with temperature of about 1000-1200 °C was recorded in highly diluted by NaF starting mixtures. The by-products of combustion reaction (NaF and MgO) were subsequently removed by leaching with acid and washing with water. The as-prepared MoSi2 nanopowder composed of spherical and dendritic shape particles was consolidated using the spark plasma sintering method at 1200-1500 °C and 50 MPa for 10 min. The result was dense compacts (98.6% theoretical density) possessing submicron grains and exhibiting hardness of 8.74-12.92 GPa.

Effect of Fluoride-Containing Toothpastes on Enamel Demineralization and Streptococcus mutans Biofilm Architecture.

PubMed

Fernández, Constanza E; Fontana, Margherita; Samarian, Derek; Cury, Jaime A; Rickard, Alexander H; González-Cabezas, Carlos

This study aimed to explore the effect of fluoridated toothpastes on biofilm architecture and enamel demineralization in an in vitro biofilm model. Streptococcus mutans was grown on enamel and treated with slurries of commercial toothpastes, containing SnF2 or NaF. Water and chlorhexidine were used as negative and positive controls, respectively. The developed biofilms were imaged and enamel demineralization was measured. SnF2 and NaF toothpaste treatments significantly reduced enamel demineralization, but SnF2 toothpaste was more effective. Only SnF2 toothpaste and chlorhexidine treatments caused reductions on biofilm mass and thickness. In conclusion, this biofilm model was able to differentiate the effects of the SnF2 and NaF toothpastes on biofilm architecture and enamel demineralization. © 2016 S. Karger AG, Basel.

Preparation of Drug-loaded Chitosan Microspheres and Its Application in Paper-based PVC Wallpaper

NASA Astrophysics Data System (ADS)

Lin, Hui; Chen, Lihui; Yan, Guiyang; Chen, Feng; Huang, Liulian

2018-03-01

By screening through test, it was found that the drug-loaded chitosan microspheres with the average particle size of 615 nm may be prepared with NaF as the mold-proof drug, chitosan as the drug carrier and sodium tripolyphosphate as the cross-linking agent; and they can improve the aspergillus niger-proof effect if loaded onto the base paper surface of the paper-based PVC wallpaper. The results show that NaF and chitosan have mold-proof synergistic effects; the mold-proof effect of the wallpaper may be improved by increasing the dose of chitosan; when the mass ratio of NaF, sodium tripolyphosphate and chitosan was 2:7:28, the paper-based PVC wallpaper with good mold-proof property can be prepared.

Comparison of the incipient lesion enamel fluoride uptake from various prescription and OTC fluoride toothpastes and gels.

PubMed

Schemehorn, B R; DiMarino, J C; Movahed, N

2014-01-01

The objective of this in vitro study was to compare the fluoride uptake into incipient enamel lesions of a novel 970 ppm F- ion SnF2 over-the-counter (OTC) gel (Enamelon Preventive Treatment Gel) and a novel 1150 ppm F- ion OTC toothpaste (Enamelon), each delivering amorphous calcium phosphate (ACP), to the uptake from two different prescription strength, 5000 ppm F- ion dentifrices containing tri-calcium phosphate (TCP) and a prescription 900 ppm F- ion paste containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). The test procedure followed method #40 in the US-FDA Anticaries Drug Products for OTC Human Use, Final Monograph testing procedures. Eight sets of twelve incisor enamel cores were mounted in Plexiglas rods and the exposed surfaces were polished. The indigenous fluoride levels of each specimen were determined prior to treatment. The treatments were performed using slurries of a negative control (water) and the following products applied to a set of sound enamel cores: 5000 ppm F- ion, sodium fluoride (NaF) prescription (Rx) dentifrice "A" containing TCP; 5000 ppm F- ion, NaF Rx dentifrice "B" containing TCP; 900 ppm F- ion, NaF Rx paste with CPP-ACP; 1150 ppm F- ion, NaF OTC toothpaste; 1150 ppm F- ion, stannous fluoride (SnF2) OTC toothpaste delivering ACP (Enamelon); 1100 ppm F- ion, SnF2 OTC toothpaste; and 970 ppm F- ion, SnF2 OTC gel delivering ACP (Enamelon Preventive Treatment Gel). The twelve specimens of each group were immersed into 25 ml of their assigned slurry with constant stirring (350 rpm) for 30 minutes. Following treatment, one layer of enamel was removed from each specimen and analyzed for fluoride and calcium. The pre-treatment fluoride (indigenous) level of each specimen was subtracted from the post-treatment value to determine the change in enamel fluoride due to the test treatment. The increase in the average fluoride uptake for treated enamel cores was: 10,263 ± 295 ppm for the 970 ppm F- ion, Enamelon Preventive Treatment Gel; 7,016 ± 353 ppm for the 1150 ppm F- ion Enamelon Toothpaste; 4,138 ± 120 ppm for the 5000 ppm F- ion, NaF prescription dentifrice "A" with TCP; 3801 ± 121 ppm for the 5000 ppm F- ion, NaF prescription dentifrice "B" with TCP; 2,647 ± 57 ppm for the 1100 ppm F- ion, SnF2 OTC toothpaste; 1470 ± 40 ppm for the 1150 ppm F- ion, NaF OTC toothpaste; and 316 ± 9 ppm for the 900 ppm F- ion, NaF paste with CPP-ACP. The differences among all the products tested were statistically significant (p < 0.05), except for the two 5000 ppm F- ion products with TCP that were not statistically different from one another, and the 900 ppm F ion, NaF paste with CPP-ACP that was not statistically different from the negative water control. The Enamelon products (970 ppm and 150 ppm F ion, SnF2OTC dentifrices) delivering ACP provide statistically significantly more fluoride to incipient enamel lesions than two prescription strength 5000 ppm F- ion toothpastes containing TCP, the 900 ppm F- ion prescription paste containing CPP-ACP, and the other OTC toothpastes compared in this study.

Comparison of antimicrobial effects of titanium tetrafluoride, chlorhexidine, xylitol and sodium fluoride on streptococcus mutans: An in-vitro study.

PubMed

Eskandarian, Tahereh; Motamedifar, Mohammad; Arasteh, Peyman; Eghbali, Seyed Sajad; Adib, Ali; Abdoli, Zahra

2017-03-01

No studies have yet documented the bactericidal effects of TiF4, and its role in the treatment of dental caries, and no definite protocol has been introduced to regulate its use. The aim of this study was to determine the antimicrobial/bactericidal effects of TiF4 on Streptococcus Mutans ( S. Mutans ) and to compare it with chlorhexidine (Chx), sodium fluoride (NaF) and xylitol. This study was conducted at the Shiraz University of Medical Sciences microbiology laboratory during March 2015 to September 2015. In this in-vitro study, first a bacterial suspension was prepared and adjusted to a 0.5 McFarland standard (equivalent to 1×10 8 CFU/ml). The minimal inhibitory concentration (MIC) and minimal bactericidal concentrations (MBC) of TiF4, Chx, NaF and xylitol were assessed using broth microdilution assay and disk diffusion methods. In order to neutralize the acidic nature of TiF4, we used a sodium hydroxide preparation to obtain a pH of 7.2 and repeated all of the previous tests with the neutralized TiF4 solution. We reported the final results as percentages where appropriate. The MIC of TiF4, NaF and Chx for S. Mutans were 12.5%, 12.5% and 6.25%, respectively. At a concentration of 12.5% the inhibition zone diameters were 9 mm, 15mm and 14mm for TiF4, NaF and Chx, respectively. The MBC was 25%, 12.5% and 12.5% for TiF4, NaF and Chx, respectively. Xylitol failed to show any bactericidal or growth inhibitory effect in all of its concentrations. When we repeated the tests with an adjusted pH, identical results were obtained. TiF4 solutions have anti-growth and bactericidal effects on S. Mutans at a concentration of 12.5% which is comparable with chlorhexidine and NaF, indicating the possible use of this solution in dental practice as an anti-cariogenic agent, furthermore the antimicrobial activity is unaffected by pH of the environment.

Comparison of antimicrobial effects of titanium tetrafluoride, chlorhexidine, xylitol and sodium fluoride on streptococcus mutans: An in-vitro study

PubMed Central

Eskandarian, Tahereh; Motamedifar, Mohammad; Arasteh, Peyman; Eghbali, Seyed Sajad; Adib, Ali; Abdoli, Zahra

2017-01-01

Introduction No studies have yet documented the bactericidal effects of TiF4, and its role in the treatment of dental caries, and no definite protocol has been introduced to regulate its use. The aim of this study was to determine the antimicrobial/bactericidal effects of TiF4 on Streptococcus Mutans (S. Mutans) and to compare it with chlorhexidine (Chx), sodium fluoride (NaF) and xylitol. Methods This study was conducted at the Shiraz University of Medical Sciences microbiology laboratory during March 2015 to September 2015. In this in-vitro study, first a bacterial suspension was prepared and adjusted to a 0.5 McFarland standard (equivalent to 1×108 CFU/ml). The minimal inhibitory concentration (MIC) and minimal bactericidal concentrations (MBC) of TiF4, Chx, NaF and xylitol were assessed using broth microdilution assay and disk diffusion methods. In order to neutralize the acidic nature of TiF4, we used a sodium hydroxide preparation to obtain a pH of 7.2 and repeated all of the previous tests with the neutralized TiF4 solution. We reported the final results as percentages where appropriate. Results The MIC of TiF4, NaF and Chx for S. Mutans were 12.5%, 12.5% and 6.25%, respectively. At a concentration of 12.5% the inhibition zone diameters were 9 mm, 15mm and 14mm for TiF4, NaF and Chx, respectively. The MBC was 25%, 12.5% and 12.5% for TiF4, NaF and Chx, respectively. Xylitol failed to show any bactericidal or growth inhibitory effect in all of its concentrations. When we repeated the tests with an adjusted pH, identical results were obtained. Conclusion TiF4 solutions have anti-growth and bactericidal effects on S. Mutans at a concentration of 12.5% which is comparable with chlorhexidine and NaF, indicating the possible use of this solution in dental practice as an anti-cariogenic agent, furthermore the antimicrobial activity is unaffected by pH of the environment. PMID:28461883

Combined effect of fluoride and 2,3,7,8-tetrachlorodibenzo-p-dioxin on mouse dental hard tissue formation in vitro.

PubMed

Salmela, Eija; Lukinmaa, Pirjo-Liisa; Partanen, Anna-Maija; Sahlberg, Carin; Alaluusua, Satu

2011-08-01

Fluoride interferes with enamel matrix secretion and mineralization and dentin mineralization. The most toxic dioxin congener, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), also impairs dental hard tissue formation and mineralization in vitro and in vivo. Our aim was to investigate in vitro whether the combined effect of sodium fluoride (NaF) and TCDD on dental hard tissue formation is potentiative. For this purpose, mandibular first and second molar tooth germs of E18 mouse embryos were cultured for 5-12 days with NaF and TCDD alone at various concentrations (2.5, 5, 10, 12.5, 15, and 20 μM and 5, 10, 12.5, and 15 nM, respectively) to determine the highest concentrations, which alone cause no or negligible effects. Morphological changes were studied from the whole tooth photographs and histological tissue sections. The concentrations found were 15 μM for NaF and 10 nM for TCDD. While at these concentrations, the effects of NaF and TCDD alone were barely detectable, the effect of simultaneous exposure on dentin and enamel formation was overt; mineralization of predentin to dentin and enamel matrix secretion and mineralization were impaired. Immunohistochemical analysis revealed that the combined exposure modified amelogenin expression by odontoblasts. Morphology of ameloblasts and the expression of amelogenin indicated that ameloblasts were still secretory. The results show that NaF and TCDD have potentiative, harmful effects on the formation of dental hard tissues. Since children can be exposed to subclinical levels of fluoride and dioxins during early childhood, coincidently with mineralization of the first permanent teeth, this finding may have clinical significance.

Promotion of enamel caries remineralization by an amelogenin-derived peptide in a rat model.

PubMed

Han, Sili; Fan, Yingying; Zhou, Zhengli; Tu, Huanxin; Li, Danxue; Lv, Xueping; Ding, Longjiang; Zhang, Linglin

2017-01-01

An amelogenin-derived peptide has been shown to promote remineralization of demineralized enamel in an in vitro model of initial caries induced by pH cycling. The present study examines whether the peptide exerts similar effects within the complex oral environment in vivo. Specific pathogen-free Sprague-Dawley rats (n=36) were infected with Streptococcus mutans, given ad libitum access to Diet 2000 and drinking water supplemented with sucrose (10%, w/v), and then randomly divided into three groups treated with 25μM peptide solution, 1g/L NaF or deionized water. Molar teeth were swabbed twice daily with the respective solutions for 24days. Then animals were killed, their jaws were removed and caries lesions were analyzed using the quantitative light-induced fluorescence-digital (QLF-D) technique to measure changes in mineral content. To verify QLF-D results, caries were scored for lesion depth and size using the Keyes method, and analyzed using polarized light microscopy (PLM). Mineral gain was significantly higher in teeth treated with peptide or NaF than in teeth treated with water (p<0.05), based on the QLF-D results (ΔF and ΔQ). Incidence of smooth-surface and sulcal caries based on Keyes scores was similar in rats treated with peptide or NaF, and significantly lower in these groups than in rats treated with water (p<0.05). Lesions on teeth treated with peptide or NaF were shallower, based on PLM. No significant differences were observed between molar enamel caries treated with peptide or NaF. This amelogenin-derived peptide can promote remineralization in a rat caries model, indicating strong potential for clinical use. Copyright © 2016 Elsevier Ltd. All rights reserved.

Diagnostic test accuracy study of 18F-sodium fluoride PET/CT, 99mTc-labelled diphosphonate SPECT/CT, and planar bone scintigraphy for diagnosis of bone metastases in newly diagnosed, high-risk prostate cancer

PubMed Central

Fonager, Randi F; Zacho, Helle D; Langkilde, Niels C; Fledelius, Joan; Ejlersen, June A; Haarmark, Christian; Hendel, Helle W; Lange, Mine Benedicte; Jochumsen, Mads R; Mortensen, Jesper C; Petersen, Lars J

2017-01-01

The aim of this study was to prospectively compare planar, bone scan (BS) versus SPECT/CT and NaF PET/CT in detecting bone metastases in prostate cancer. Thirty-seven consecutive, newly diagnosed, prostate cancer patients with prostate specific antigen (PSA) levels ≥ 50 ng/mL and who were considered eligible for androgen-deprivation therapy (ADT) were included in this study. BS, SPECT/CT, and NaF PET/CT, were performed prior to treatment and were repeated after six months of ADT. Baseline images from each index test were independently read by two experienced readers. The reference standard was based on a consensus decision made by a multidisciplinary team on the basis of baseline and follow-up images of the index tests, the findings of the baseline index tests by the experienced readers, and any available imaging, biochemical, and clinical data, including the response to ADT. Twenty-seven (73%) of the 37 patients had bone metastases according to the reference standard. The sensitivities for BS, SPECT/CT and NaF PET/CT were 78%, 89%, and 89%, respectively, and the specificities were 90%, 100%, and 90%, respectively. The positive predictive values of BS, SPECT/CT and NaF PET/CT were 96%, 100%, and 96%, respectively, and the negative predictive values were 60%, 77% and 75%, respectively. No statistically significant difference among the three imaging modalities was observed. All three imaging modalities showed high sensitivity and specificity. NaF PET/CT and SPECT/CT showed numerically improved, but not statistically superior, sensitivity compared with BS in this limited and selected patient cohort. PMID:29181269

Nano-encapsulation of Dietary Phytoconstituent Capsaicin on Emulsome: Evaluation of Anticancer Activity Through the Measurement of Liver Oxidative Stress in Rats.

PubMed

Giri, Tapan K; Pramanik, Kaustav; Barman, Tapan K; Maity, Subhasis

2017-01-01

Excessive reactive species derived from oxygen and nitrogen leads to oxidative damage to tissue and organs. Capsaicin (CAP), a pungent component found in red pepper can prevent oxidative stress. The aim of the present work was to evaluate the protective effects of CAP loaded nano-emulsomes (EML) against the oxidative stress of rat livers induced through sodium fluoride (NaF). EML was prepared by thin film hydration method that is development of thin lipid film followed by hydration and sonication. EML was characterized by Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) techniques. EML was evaluated for drug entrapment, in vitro drug release, and in vivo study. In vitro drug release study of optimized formulation showed that 50% of CAP was released within 50.21 min while 85% CAP was released in 227.4 min. Single oral dose of free CAP and CAP loaded EML were given to rats 2 hour after NaF administration. Membrane of hepatic cells was damaged by NaF and it was judged by the estimation of lipid peroxidation, reactive oxygen species (ROS), and catalase activity. The administration of CAP loaded EML 2 hr after NAF consumption showed significant decrease in ROS level compared to free CAP. EML containing CAP was more effective in comparison to free CAP in controlling the lipid peroxidation that is thiobarbituric acid substance augmentation in liver by the treatment of NaF. The administration of CAP loaded EML showed significant increase in catalase activity compared to free CAP administration. The results clearly demonstrated that CAP loaded EML may be accepted as an effective therapeutic formulation in preventing oxidative damage. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Effect of NaF and TiF(4) varnish and solution on bovine dentin erosion plus abrasion in vitro.

PubMed

Magalhães, Ana Carolina; Levy, Flávia Mauad; Rizzante, Fábio A; Rios, Daniela; Buzalaf, Marília Afonso Rabelo

2012-03-01

This in vitro study aimed to analyze the effect of TiF(4) compared to NaF varnishes and solutions, to protect against dentin erosion associated with abrasion. Bovine dentin specimens were pre-treated with NaF-Duraphat (2.26% F), NaF/CaF(2)-Duofluorid (5.63% F), experimental-NaF (2.45% F), experimental-TiF(4) (2.45% F) and placebo varnishes; NaF (2.26% F) and TiF(4) (2.45% F) solutions. Controls remained untreated. The erosive pH cycling was performed using a soft drink (pH 2.6) 4 × 90 s/day and the toothbrushing-abrasion 2 × 10 s/day, in vitro for 5 days. Between the challenges, the specimens were exposed to artificial saliva. Dentin tissue loss was measured profilometrically (μm). ANOVA/Tukey's test showed that all fluoridated varnishes (Duraphat, 7.5 ± 1.1; Duofluorid, 6.8 ± 1.1; NaF, 7.2 ± 1.9; TiF(4), 6.5 ± 1.0) were able to significantly reduce dentin tissue loss (40.7% reduction compared to control) when compared to placebo varnish (11.2 ± 1.3), control (11.8 ± 1.7) and fluoridated (NaF, 9.9 ± 1.8; TiF(4), 10.3 ± 2.1) solutions (p < 0.0001), which in turn did not significantly differ from each other. All fluoridated varnishes, but not the solutions, had a similar performance and a good potential to reduce dentin tissue loss under mild erosive and abrasive conditions in vitro. Risk patients for erosion and abrasion, especially those with exposed dentin, should benefit from this clinical preventive measure. Further research has to confirm this promising result in the clinical situation.

Antibacterial activity against Streptococcus mutans and inhibition of bacterial induced enamel demineralization of propolis, miswak, and chitosan nanoparticles based dental varnishes.

PubMed

Wassel, Mariem O; Khattab, Mona A

2017-07-01

Using natural products can be a cost-effective approach for caries prevention especially in low income countries where dental caries is highly prevalent and the resources are limited. Specially prepared dental varnishes containing propolis, miswak, and chitosan nanoparticles (CS-NPs) with or without sodium fluoride (NaF) were assessed for antibacterial effect against Streptococcus mutans ( S. mutans ) using disk diffusion test. In addition, the protective effect of a single pretreatment of primary teeth enamel specimens against in vitro bacterial induced enamel demineralization was assessed for 3 days. All natural products containing varnishes inhibited bacterial growth significantly better than 5% NaF varnish, with NaF loaded CS-NPs (CSF-NPs) showing the highest antibacterial effect, though it didn't significantly differ than those of other varnishes except miswak ethanolic extract (M) varnish. Greater inhibitory effect was noted with varnish containing freeze dried aqueous miswak extract compared to that containing ethanolic miswak extract, possibly due to concentration of antimicrobial substances by freeze drying. Adding natural products to NaF in a dental varnish showed an additive effect especially compared to fluoride containing varnish. 5% NaF varnish showed the best inhibition of demineralization effect. Fluoride containing miswak varnish (MF) and CSF-NPs varnish inhibited demineralization significantly better than all experimental varnishes, especially during the first 2 days, though CSF-NPs varnish had a low fluoride concentration, probably due to better availability of fluoride ions and the smaller size of nanoparticles. Incorporating natural products with fluoride into dental varnishes can be an effective approach for caries prevention, especially miswak and propolis when financial resources are limited.

Crustal anisotropy along the North Anatolian Fault Zone from receiver functions

NASA Astrophysics Data System (ADS)

Licciardi, Andrea; Eken, Tuna; Taymaz, Tuncay; Piana Agostinetti, Nicola; Yolsal-Çevikbilen, Seda; Tilmann, Frederik

2016-04-01

The North Anatolian Fault Zone (NAFZ) that is considered to be one of the largest plate-bounding transform faults separates the Anatolian Plate to the south from the Eurasian Plate to the north. A proper estimation of the crustal anisotropy in the area is a key point to understand the present and past tectonic processes associated with the plate boundary as well as for assessing its strength and stability. In this work we used data from the North Anatolian Fault (NAF) passive seismic experiment in order to retrieve the anisotropic properties of the crust by means of the receiver function (RF) method. This approach provides robust constraints on the location at depth of anisotropic bodies compared to other seismological tools like S-waves splitting observations where anisotropic parameters are obtained through a path-integrated measurement process over depth. We computed RFs from teleseismic events, for 39 stations with a recording period of nearly 2 years, providing an excellent azimuthal coverage. The observed azimuthal variations in amplitudes and delay times on the Radial and Transverse RF indicate the presence of anisotropy in the crust. Isotropic and anisotropic effects on the RFs are analyzed separately after harmonic decomposition of the RF dataset (Bianchi et al. 2010). Pseudo 2D profiles are built to observe both the seismic isotropic structure and the depth-dependent lateral variations of crustal anisotropy in the area, including orientation of the symmetry axis. Preliminary results show that the isotropic structure is characterized by a complex crustal setting above a nearly flat Moho at a depth of ~40 km in the central portion of the studied area. Strong anisotropy is present in the upper crust along some portions of the NAFZ and the Ezinepazari-Sungurlu Fault (ESF), with a strong correlation between the orientation of the symmetry axis of anisotropy and the strike of the main geological structures. More complex patterns of anisotropy are present in the middle and lower crust as well as in the upper mantle. Bianchi, I., J. Park, N. Piana Agostinetti, and V. Levin (2010), Mapping seismic anisotropy using harmonic decomposition of receiver functions: An application to Northern Apennines, Italy, J. Geophys. Res., 115, B12317, doi:10.1029/2009JB007061.

Complex Hydrocarbon Seepages Along a Short Segment of the North Anatolian Fault (Sea of Marmara, Turkey).

NASA Astrophysics Data System (ADS)

Ruffine, L.; Croguennec, C.; Donval, J. P.; Rinnert, E.; Germain, Y.; Bignon, L.; Scalabrin, C.; Ondreas, H.; Alix, A. S.; Legoix, L.; Bermell, S.; Géli, L.

2016-02-01

The Sea of Marmara represents an outstanding environment for geoscientists to investigate on complex hydrocarbon migration through faults. It is characterized by a large number of seeps located along the faults and the basin edge, very diverse in composition, origin and flux. MARSITECruise in November 2014 corresponds to the latest expedition in a long series of scientific expeditions started in early 2000. During this multidisciplinary expedition, an ROV dive has been undertaken to study natural hydrocarbon emissions along the Ganos fault, a segment of the North Anatolian Faults (NAF) located at the westernmost part of the Sea of Marmara. The seafloor inspection revealed the presence of both oil and gas seeps. Six gas seeps have been sampled using an in-situ pressure-preservation device. The selection of the seeps to sample relied on both in situRaman analyses, followed by onboard measurement of the molecular and isotopic compositions of the collected gases. The gas flow-rate of each seep was also measured prior sampling. The results show that the sampled gases are highly heterogeneous from one seep to another, with methane molecular composition and δ13C varying between 2 and 99 % -mol and 34 and 58.4 ‰, respectively. In this communication, the hydrocarbon origin and flow-rate are discussed, as well as the influence area of each source. Acoustic data combined with video recording from the ROV-dive have also been used to discuss their fate into the water column. References Bourry, C., B. Chazallon, J. L. Charlou, J. P. Donval, L. Ruffine, P. Henry, L. Géli, M. N. Cagatay, S. Inan, and M. Moreau (2009), Free gas and gas hydrates from the Sea of Marmara, Turkey Chemical and structural characterization, Chem. Geol., 264(1-4), 197-206. Dupré, S., C. Scalabrin, L. Géli, P. Henry, C. Grall, J.-B. Tary, M. N. Çagatay, and C. Imren (2010), the MARMESONET Scientific Party Team Widespread gas emissions in the Sea of Marmara in relation with the tectonic and sedimentary environments: Results from shipborne multibeam echosounder water column imagery (MARMESONET expedition, 2009), European Geosciences Union General Assembly 2010, 2-7 May, Geophysical Research Abstracts, pp. 9429-9422, Vienna, Austria.

Soy Food Intake and Biomarkers of Breast Cancer Risk: Possible Difference in Asian Women?

PubMed Central

Maskarinec, Gertraud; Ju, Dan; Morimoto, Yukiko; Franke, Adrian A.; Stanczyk, Frank Z.

2017-01-01

Soy foods may protect against breast cancer in Asian but not in Western populations. We examined if the levels of various markers of breast cancer risk and inflammation, as well as the effects of soy food consumption on these markers, differ between Asian and non-Asian premenopausal women in two soy intervention trials. One study randomized 220 women to a 2-year intervention and the other one randomized 96 women in a cross-over design to examine the effects of consumption of 2 daily soy servings on nipple aspirate fluid (NAF) volume, estrogens in serum, NAF, and urine, insulin-like growth factor-1 (IGF-1), IGF binding protein 3, and inflammatory markers in serum, and mammographic densities. Mixed linear models were applied to assess ethnic differences in biomarkers and response to the soy diet. Serum C-reactive protein, serum leptin, NAF volume, and NAF estrone-sulfate were lower, while urinary isoflavones were higher in Asian than in non-Asian women. A significant interaction (pinteraction=0.05) between ethnicity and soy diet was observed for IGF-1 but not for other biomarkers. The current findings suggest possible ethnic differences in levels of biomarkers for breast cancer risk but little evidence that Asian women respond differently to soy foods than non-Asian women. PMID:27918846

New horizon for breast cancer biomarker discoveries: What might the liquid biopsy of nipple aspirate fluid hold?

PubMed

Mannello, Ferdinando

2017-09-01

The existence of cellular, molecular and biochemical heterogeneity of human breast cancers reveals the intricacy of biomarkers complexity, stimulating studies on new approaches (like "liquid biopsies") for the improvements in precision medicine. Breast cancer is recognized as a leading cause of morbidity and mortality worldwide with tumors significantly diverse and containing many types of cells showing different genetic and epigenetic profiles. In this field, the technology of liquid biopsy (applied to a fluid produced by breast gland, named nipple aspirate fluids, NAF) highlights the power of combining basic and clinical research. NAF is the mirror of the entire ductal/alveolar breast tree providing almost complete proteomic profile and a valuable source for biomarker discovery, in non-invasive manner than tissue biopsies. The liquid biopsy technology using NAF may represent the outstanding breakthrough of proteomic cancer research revealing novel diagnostic and prognostic applications. In conjunction to metabolomic and degradome profiling, the use of NAF as liquid biopsy approach will improve the detection of changes in the cellular microenvironment of the breast tumors, understanding molecular and biochemical mechanisms which drive breast tumor initiation, maintenance and progression, and finally enhancing the development of novel drug targets and new treatment strategies. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fluorine-induced apoptosis and lipid peroxidation in human hair follicles in vitro.

PubMed

Wang, Zheng-hui; Li, Xiao-li; Yang, Zhuang-qun; Xu, Min

2010-12-01

Fluoride is an essential trace element for human body; however, exposure to high amounts of fluoride has been documented to be correlated with an increasing risk of hair loss. To date, little is known about the mechanism(s) of how fluoride affects hair follicles. Here, we demonstrated that middle (1.0 mmol/L) and high (10.0 mmol/L) concentrations of sodium fluoride (NaF) significantly inhibited hair follicle elongation in vitro, but low NaF (0.1 mmol/L) showed little influence. Moreover, treatment with high levels of NaF resulted in a marked increase in terminal dUTP nick end labeling-positive cells in the outer layer of the outer root sheath, the dermal sheath, and the lower bulb matrix surrounding dermal papilla. Furthermore, the enhanced apoptosis was coupled with an increased oxidative stress manifested as higher malondialdehyde content. Additionally, the presence of selenium considerably antagonized the effects of middle NaF on hair follicles, with regard to either the suppression of hair growth or the induction of oxidative stress and apoptosis. In conclusion, exposure to high levels of fluoride compromises hair follicle growth and accelerate cell apoptosis in vitro. The toxicity of fluoride can be reduced by selenium, at least partially via the suppression of intracellular oxidative stress.

Reproductive and developmental toxicity of degradation products of refrigerants in experimental animals.

PubMed

Ema, Makoto; Naya, Masato; Yoshida, Kikuo; Nagaosa, Ryuichi

2010-01-01

The present paper summarizes the results of animal studies on the reproductive and developmental toxicity of the degradation products of refrigerants, including trifluoroacetic acid (TFA), carbon dioxide (CO(2)), carbon monoxide (CO), carbonyl fluoride (CF), hydrogen fluoride (HF) and formic acid (FA). Excessive CO(2) in the atmosphere is testicular and reproductive toxic, embryolethal, developmentally neurotoxic and teratogenic in experimental animals. As for CO, maternal exposure causes prenatal and postnatal lethality and growth retardation, skeletal variations, cardiomegaly, blood biochemical, immunological and postnatal behavioral changes, and neurological impairment in offspring of several species. Very early studies of CO in rats and guinea pigs reported fetal malformations in exposed dams. The results of toxicological studies on sodium fluoride (NaF) were used to obtain insight into the toxicity of CF and HF, because CF is rapidly hydrolyzed in contact with water yielding CO(2) and HF, and NaF is similar in kinetics and dynamics to HF. Increased fetal skeletal variation, but not malformation, was noted after the maternal administration of NaF. Rat multiple-generation studies revealed that NaF caused retarded ossification and degenerative changes in the lung and kidney in offspring. There is a lack of information about the toxicity of TFA and FA. Copyright 2009 Elsevier Inc. All rights reserved.

Solubilization of bovine corpus-luteum adenylate cyclase in lubrol-PX, triton X-100 or digitonin and the stabilizing effect of sodium fluoride present in the solubilization medium.

PubMed

Young, J L; Stansfield, D A

1978-09-01

1. Adenylate cyclase activity of the washed 600g sediment of bovine corpus-luteum homogenate was solubilized by Lubrol-PX, Triton X-100 and digitonin. Digitonin was the least destructive of NaF-stimulated activity. 2. NaF, present in the solubilization medium together with MgSO4, increased the percentage yields of soluble activity from untreated 600g sediment and 600g sediment which had been preincubated with p[NH]ppG (guanosine 5'-[betagamma-imido]triphosphate). The stabilizing influence of NaF was most marked with digitonin. However, the highest specific activities of soluble enzyme were obtained with Lubrol-PX as solubilizing agent, since digitonin solubilized more membrane protein than does Lubrol-PX, and less of the activity of the digitonin-dispersed 600g sediment was recovered in the 105000g supernatant. 3. p[NH]ppG also has a stabilizing effect when present during the solubilization, but less so than NaF. 4. Both NaF and MgSO4 alone have a stabilizing effect during solubilization. The greatest amounts of soluble activity were obtained with both agents present in the solubilization medium, there being a synergistic effect.

Solubilization of bovine corpus-luteum adenylate cyclase in lubrol-PX, triton X-100 or digitonin and the stabilizing effect of sodium fluoride present in the solubilization medium.

PubMed Central

Young, J L; Stansfield, D A

1978-01-01

1. Adenylate cyclase activity of the washed 600g sediment of bovine corpus-luteum homogenate was solubilized by Lubrol-PX, Triton X-100 and digitonin. Digitonin was the least destructive of NaF-stimulated activity. 2. NaF, present in the solubilization medium together with MgSO4, increased the percentage yields of soluble activity from untreated 600g sediment and 600g sediment which had been preincubated with p[NH]ppG (guanosine 5'-[betagamma-imido]triphosphate). The stabilizing influence of NaF was most marked with digitonin. However, the highest specific activities of soluble enzyme were obtained with Lubrol-PX as solubilizing agent, since digitonin solubilized more membrane protein than does Lubrol-PX, and less of the activity of the digitonin-dispersed 600g sediment was recovered in the 105000g supernatant. 3. p[NH]ppG also has a stabilizing effect when present during the solubilization, but less so than NaF. 4. Both NaF and MgSO4 alone have a stabilizing effect during solubilization. The greatest amounts of soluble activity were obtained with both agents present in the solubilization medium, there being a synergistic effect. PMID:568467

Sodium fluoride adversely affects ovarian development and reproduction in Drosophila melanogaster.

PubMed

Khatun, Salma; Rajak, Prem; Dutta, Moumita; Roy, Sumedha

2017-11-01

The study demonstrates the effects of chronic sub-lethal exposure of sodium fluoride (NaF) on reproductive structure and function of female Drosophila melanogaster. As a part of treatment, flies were maintained in food supplemented with sub-lethal concentrations of NaF (10-100 μg/mL). Fecundity, ovarian morphology, presence and profusion of viable cells from ovary and fat body were taken into consideration for evaluating changes in reproductive homeostasis. Wing length (a factor demonstrating body size and reproductive fitness) was also monitored after NaF exposure. Significant reduction in fecundity, alteration in ovarian morphology along with an increase in apoptosis was observed in treated females. Simultaneous decline in viable cell number and larval weight validates the result of MTT assay. Furthermore, altered ovarian Glucose-6-phosphate dehydrogenase and catalase activities together with increased rate of lipid peroxidation after 20 and 40 μg/mL NaF exposure confirmed the changes in reproduction related metabolism. Enhanced lipid peroxidation known for ROS generation might have induced genotoxicity which is confirmed through Comet assay. The enzyme activities were not dose dependent, rather manifested a bimodal response, which suggests a well-knit interaction among the players inducing stress and the ones that help establish physiological homeostasis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Soy Food Intake and Biomarkers of Breast Cancer Risk: Possible Difference in Asian Women?

PubMed

Maskarinec, Gertraud; Ju, Dan; Morimoto, Yukiko; Franke, Adrian A; Stanczyk, Frank Z

2017-01-01

Soy foods may protect against breast cancer in Asian but not in Western populations. We examined if the levels of various markers of breast cancer risk and inflammation, as well as the effects of soy food consumption on these markers, differ between Asian and non-Asian premenopausal women in two soy intervention trials. One study randomized 220 women to a 2-yr intervention and the other one randomized 96 women in a crossover design to examine the effects of consumption of 2 daily soy servings on nipple aspirate fluid (NAF) volume; estrogens in serum, NAF, and urine; insulin-like growth factor-1 (IGF-1), IGF-binding protein 3, and inflammatory markers in serum; and mammographic densities. Mixed linear models were applied to assess ethnic differences in biomarkers and response to the soy diet. Serum C-reactive protein, serum leptin, NAF volume, and NAF estrone sulfate were lower, while urinary isoflavones were higher in Asian than in non-Asian women. A significant interaction (p interaction = 0.05) between ethnicity and soy diet was observed for IGF-1 but not for other biomarkers. The current findings suggest possible ethnic differences in levels of biomarkers for breast cancer risk but little evidence that Asian women respond differently to soy foods than non-Asian women.

Improved detection and relocation of micro-earthquakes applied to the Sea of Marmara

NASA Astrophysics Data System (ADS)

Tary, J. B.; Evangelia, B.; Géli, L.; Lomax, A.

2016-12-01

The Sea of Marmara is located at the western end of the North Anatolian Fault (NAF). This part of the NAF is considered as a seismic gap, being between the Izmit and Duzce earthquakes to the East and the Ganos earthquake to the West. Improved detection and location of seismicity in the Sea of Marmara is important for defining the seismic hazard in this area.On July 25, 2011, a Mw 5 earthquake occurred below the Western High in the western part of the Sea of Marmara. This earthquake as well as its aftershock sequence were recorded by a network of 10 ocean bottom seismometers (Ifremer) as well as seafloor observatories (KOERI). The OBSs were deployed from mid-April, 2011, to the end of July, 2011.The aftershock sequence is characterized by deep seismicity ( 10-15 km) around the main shock and shallow seismicity. Some of the shallow seismicity could be located at a similar depth as gas prone sediment layers below the Western High. The exact causes of these shallow aftershocks are still unclear. To better define this aftershock sequence, we use the match filter technique with a selection of aftershocks as templates to dig out child events from the continuous data streams. The templates are cross-correlated with the continuous data for stations with absolute time picks. The cross-correlation coefficients are then summed over all stations and components, and we then compute its median absolute deviation (MAD). Signals are detected when the summed cross-correlation time series exceeds a given number of times the MAD. Using a conservative detection threshold, we obtain a 10-fold increase in the number of events. The newly detected events are then relocated using the double-difference technique. With these newly detected events, we investigate the nucleation phase of the main shock and the aftershock sequence, as well as the possible triggering of the shallow aftershocks by the deeper seismicity.

Electrochemical Study and Characterization of an Amperometric Biosensor Based on the Immobilization of Laccase in a Nanostructure of TiO₂ Synthesized by the Sol-Gel Method.

PubMed

Romero-Arcos, Mariana; Garnica-Romo, Ma Guadalupe; Martínez-Flores, Héctor Eduardo

2016-07-07

Laccase amperometric biosensors were developed to detect the catechol compound. The laccase enzyme (LAC) immobilization was performed on nanostructures of (a) titania (TiO₂); (b) titania/Nafion (TiO₂/NAF) (both immobilized by the sol-gel method) and a third nanostructure, which consisted of a single biosensor composite of Nafion and laccase enzyme denoted as NAF/LAC. The Nafion was deposited on a graphite electrode and used to avoid "cracking" on the matrix. The TiO₂ particle size was an average of 66 nm. FTIR spectroscopy vibration modes of different composites were determined. The electrochemical behavior of the biosensor was studied using electrochemical spectroscopy (EIS) and cyclic voltammetry (CV). The biosensor based on TiO₂/NAF/LAC presented the best electro-chemical properties with regard to sensitivity, stability and detection limit after a period of 22 days.

The NASA Auralization Framework and Plugin Architecture

NASA Technical Reports Server (NTRS)

Aumann, Aric R.; Tuttle, Brian C.; Chapin, William L.; Rizzi, Stephen A.

2015-01-01

NASA has a long history of investigating human response to aircraft flyover noise and in recent years has developed a capability to fully auralize the noise of aircraft during their design. This capability is particularly useful for unconventional designs with noise signatures significantly different from the current fleet. To that end, a flexible software architecture has been developed to facilitate rapid integration of new simulation techniques for noise source synthesis and propagation, and to foster collaboration amongst researchers through a common releasable code base. The NASA Auralization Framework (NAF) is a skeletal framework written in C++ with basic functionalities and a plugin architecture that allows users to mix and match NAF capabilities with their own methods through the development and use of dynamically linked libraries. This paper presents the NAF software architecture and discusses several advanced auralization techniques that have been implemented as plugins to the framework.

Novel duplex vapor: Electrochemical method for silicon solar cells. [chemical reactor for a silicon sodium reaction system

NASA Technical Reports Server (NTRS)

Nanis, L.; Sanjurjo, A.; Sancier, K.

1979-01-01

The scaled up chemical reactor for a SiF4-Na reaction system is examined for increased reaction rate and production rate. The reaction system which now produces 5 kg batches of mixed Si and NaF is evaluated. The reactor design is described along with an analysis of the increased capacity of the Na chip feeder. The reactor procedure is discussed and Si coalescence in the reaction products is diagnosed.

Ameloblasts require active RhoA to generate normal dental enamel.

PubMed

Xue, Hui; Li, Yong; Everett, Eric T; Ryan, Kathleen; Peng, Li; Porecha, Rakhee; Yan, Yan; Lucchese, Anna M; Kuehl, Melissa A; Pugach, Megan K; Bouchard, Jessica; Gibson, Carolyn W

2013-08-01

RhoA plays a fundamental role in regulation of the actin cytoskeleton, intercellular attachment, and cell proliferation. During amelogenesis, ameloblasts (which produce the enamel proteins) undergo dramatic cytoskeletal changes and the RhoA protein level is up-regulated. Transgenic mice were generated that express a dominant-negative RhoA transgene in ameloblasts using amelogenin gene-regulatory sequences. Transgenic and wild-type (WT) molar tooth germs were incubated with sodium fluoride (NaF) or sodium chloride (NaCl) in organ culture. Filamentous actin (F-actin) stained with phalloidin was elevated significantly in WT ameloblasts treated with NaF compared with WT ameloblasts treated with NaCl or with transgenic ameloblasts treated with NaF, thereby confirming a block in the RhoA/Rho-associated protein kinase (ROCK) pathway in the transgenic mice. Little difference in quantitative fluorescence (an estimation of fluorosis) was observed between WT and transgenic incisors from mice provided with drinking water containing NaF. We subsequently found reduced transgene expression in incisors compared with molars. Transgenic molar teeth had reduced amelogenin, E-cadherin, and Ki67 compared with WT molar teeth. Hypoplastic enamel in transgenic mice correlates with reduced expression of the enamel protein, amelogenin, and E-cadherin and cell proliferation are regulated by RhoA in other tissues. Together these findings reveal deficits in molar ameloblast function when RhoA activity is inhibited. © 2013 Eur J Oral Sci.

Mitigation of enamel erosion using commercial toothpastes evaluated with optical coherence tomography

NASA Astrophysics Data System (ADS)

Cassimiro-Silva, Patricia Fernandes; Maia, Ana Marly Araújo; Monteiro, Gabriela Queiroz de Melo; Gomes, Anderson S. L.

2016-03-01

The aim of this study was to evaluate the efficacy of commercial toothpastes containing sodium fluoride (NaF), stannous fluoride (SnF2), or casein phosphopeptides (CPP)-amorphous calcium phosphate (ACP)/NaF regarding their potential to inhibit enamel erosion. Twenty-eight 4×4 mm enamel specimens were randomly allocated into 4 groups (n=7): negative control; Pronamel (NaF); Pro Health (SnF2/NaF); Mi Paste Plus (CPP-ACP/NaF). Erosive cycles with 0.5% citric acid, 5 times, 3 minutes/day for 7 days were performed. After the first and last cycle of each day, toothpaste slurries were applied for 2 min. The quantitative analysis was accomplished using Contact Profilometry and Optical Coherence Tomography (OCT), complemented by roughness and qualitative scanning electron microscopy (SEM) analysis. OCT and Profilometry analysis showed similar effectiveness in measuring the reduction of mineral loss. A significant increase in the mean roughness values was observed on eroded surface and also on treated surface as revealed by scanning electron microscopy. The use of SnF2/NaF toothpaste was the most effective method for reducing mineral loss. As quantitative methods, OCT and Contact Profilometry showed no statistical differences. OCT, which was used for this purpose for the first time, has the advantage of being noninvasive, and therefore have the potential for clinical application.

Fluoride bioavailability in saliva and plaque

PubMed Central

2012-01-01

Background Different fluoride formulations may have different effects on caries prevention. It was the aim of this clinical study to assess the fluoride content, provided by NaF compared to amine fluoride, in saliva and plaque. Methods Eight trained volunteers brushed their teeth in the morning for 3 minutes with either NaF or amine fluoride, and saliva and 3-day-plaque-regrowth was collected at 5 time intervals during 6 hours after tooth brushing. The amount of collected saliva and plaque was measured, and the fluoride content was analysed using a fluoride sensitive electrode. All subjects repeated all study cycles 5 times, and 3 cycles per subject underwent statistical analysis using the Wilcoxon-Mann-Whitney test. Results Immediately after brushing the fluoride concentration in saliva increased rapidly and dropped to the baseline level after 360 minutes. No difference was found between NaF and amine fluoride. All plaque fluoride levels were elevated after 30 minutes until 120 minutes after tooth brushing, and decreasing after 360 minutes to baseline. According to the highly individual profile of fluoride in saliva and plaque, both levels of bioavailability correlated for the first 30 minutes, and the fluoride content of saliva and plaque was back to baseline after 6 hours. Conclusions Fluoride levels in saliva and plaque are interindividually highly variable. However, no significant difference in bioavailability between NaF and amine fluoride, in saliva, or in plaque was found. PMID:22230722

Comparison of in vitro fluoride uptake from whitening toothpastes and a conventional toothpaste in demineralised enamel.

PubMed

Altenburger, Markus J; Bernhart, Jasmin; Schicha, Thurid D; Wrbas, Karl-Thomas; Hellwig, Elmar

2010-01-01

Studies on the compatibility of abrasives and fluoride compounds deal exclusively with fluoride uptake and remineralization after storing the enamel specimens in a toothpaste-saliva mixture. The influence of brushing on the fluoride uptake when highly abrasive toothpastes are used has hardly been investigated so far. The aim of the present study was to investigate fluoride uptake in initially demineralised dental enamel after storage in, or brushing with, whitening toothpaste slurries, compared to a conventional toothpaste. For this purpose two widely available whitening toothpastes with ionically bound fluoride (sodium fluoride NaF), two with covalently-bound fluoride toothpastes (sodium monofluorophosphate, NaMFP) and a conventional amine fluoride toothpaste (AmF) were compared. The fluoride uptake after use of the AmF toothpaste was shown to be statistically significantly higher than that after application of the NaF toothpastes, which in turn was statistically significantly higher than the uptake resulting from NaMFP application. The fluoride uptake was slightly higher when the enamel samples were brushed with NaF toothpaste, rather than just stored in the respective toothpaste slurry. Brushing with highly abrasive toothpastes did not negatively influence fluoride uptake in demineralised dental enamel. The ionic form of the fluoride in toothpastes appears to be critical for increased fluoride uptake. The acidic components of the AmF toothpaste improved fluoride uptake compared to alkaline NaF toothpastes.

Lead enhances fluoride influence on apoptotic processes in the HepG2 liver cell line.

PubMed

Gutowska, Izabela; Baranowska-Bosiacka, Irena; Siwiec, Ewa; Szczuko, Małgorzata; Kolasa, Agnieszka; Kondarewicz, Anna; Rybicka, Marta; Dunaj-Stańczyk, Małgorzata; Wiernicki, Ireneusz; Chlubek, Dariusz; Stachowska, Ewa

2016-03-01

Chronic long-term exposure to high levels of fluoride leads to fluorosis, manifested by skeletal fluorosis and damage to internal organs, including kidneys, liver, parathyroid glands, and brain. Excess fluoride can also cause DNA damage, trigger apoptosis, and change cell cycle. The effect of fluoride may be exacerbated by lead (Pb), a potent inhibitor of many enzymes and a factor causing apoptosis, still present in the environment in excessive amounts. Therefore, in this study, we investigated the effects of sodium fluoride (NaF) and/or lead acetate (PbAc) on development of apoptosis, cell vitality, and proliferation in the liver cell line HepG2. We examined hepatocytes from the liver cell line HepG2, incubated for 48 h with NaF, PbAc, and their mixture (NaF + PbAc), and used for measuring apoptosis, index of proliferation, and vitality of cells. Incubation of the hepatocytes with NaF or PbAc increased apoptosis, more when fluoride and Pb were used simultaneously. Vitality of the cells depended on the compound used and its concentration. Proliferation slightly increased and then decreased in a high fluoride environment; it decreased significantly after addition of Pb in a dose-dependent manner. When used together, fluoride inhibited the decreasing effect of Pb on cell proliferation. © The Author(s) 2013.

Effect of halide salts on development of surface browning on fresh-cut 'Granny Smith' (Malus × domestica Borkh) apple slices during storage at low temperature.

PubMed

Li, Yongxin; Wills, Ron B H; Golding, John B; Huque, Roksana

2015-03-30

The postharvest life of fresh-cut apple slices is limited by browning on cut surfaces. Dipping in halide salt solutions was examined for their inhibition of surface browning on 'Granny Smith' apple slices and the effects on biochemical factors associated with browning. Delay in browning by salts was greatest with chloride = phosphate > sulfate > nitrate with no difference between sodium, potassium and calcium ions. The effectiveness of sodium halides on browning was fluoride > chloride = bromide > iodide = control. Polyphenol oxidase (PPO) activity of tissue extracted from chloride- and fluoride-treated slices was not different to control but when added into the assay solution, NaF > NaCl both showed lower PPO activity at pH 3-5 compared to control buffer. The level of polyphenols in treated slices was NaF > NaCl > control. Addition of chlorogenic acid to slices enhanced browning but NaCl and NaF counteracted this effect. There was no effect of either halide salt on respiration, ethylene production, ion leakage, and antioxidant activity. Dipping apple slices in NaCl is a low cost treatment with few impediments to commercial use and could be a replacement for other anti-browning additives. The mode of action of NaCl and NaF is through decreasing PPO activity resulting in reduced oxidation of polyphenols. © 2014 Society of Chemical Industry.

Effects of non-aqueous fluids cuttings discharge from exploratory drilling activities on the deep-sea macrobenthic communities

NASA Astrophysics Data System (ADS)

Santos, M. F. L.; Lana, P. C.; Silva, J.; Fachel, J. G.; Pulgati, F. H.

2009-01-01

This paper assesses the effects of non-aqueous fluids (NAFs-type III) cuttings discharge from exploratory drilling activities on deep-sea macrobenthic communities in the Campos Basin, off the southeastern Brazilian coast, Rio de Janeiro State. One hundred and fifty nine sediment samples were taken with a 0.25 m 2 box corer at a depth of 902 m on three monitoring cruises: first cruise—before drilling (April 2001), second cruise—after drilling (July 2001), and third cruise—one year after drilling (July 2002). The results indicated no significant changes in values of density, number of families and functional groups related to drilling activities in the reference area (2500 m distance), and biological variations may be result from the natural variability of the fauna. Evidence indicates that drilling activities led to measurable effects on the community structure related to NAF cuttings discharge but were limited to a 500 m radius from the drilling well. Such effects were much more evident at isolated sites in the impact area (WBF and WBF+NAF areas) and are characterized as localized impacts. One year after drilling, a recolonization was observed, with the probable recovery of the macrobenthic community in most of the study area; only at part of the WBF+NAF area (stations 05, 24 and 36) was the community still undergoing recovery.

The effects of sodium fluoride and stannous fluoride on the surface roughness of intraoral magnet systems.

PubMed

Obatake, R M; Collard, S M; Martin, J; Ladd, G D

1991-10-01

Four types of intraoral magnets used for retention of overdentures and maxillofacial prostheses were exposed in vitro to SnF2 and NaF to determine the effects of fluoride rinses on surface roughness. The surface roughness (Ra) was measured, after simulated 1, 2, and 5 years' clinical exposure to fluoride (31, 62, and 155 hours). The mean change in Ra was calculated for each period of simulated exposure to fluoride for each magnet type. Two-way ANOVA was used to compare mean change in Ra between magnets within fluorides, and between fluorides within magnets. Paired t tests were used to compare mean change in Ra within fluorides within magnets. The mean change in Ra increased for all magnets after simulated 1, 2, and 5 years of exposure to SnF2 and NaF (p less than 0.03). Using the change in Ra as an indicator for corrosion, PdCo encapsulated SmCo5 magnets and their keepers demonstrated the least corrosion with either fluoride.

Risk Assessment Study of Fluoride Salts: Probability-Impact Matrix of Renal and Hepatic Toxicity Markers.

PubMed

Usuda, Kan; Ueno, Takaaki; Ito, Yuichi; Dote, Tomotaro; Yokoyama, Hirotaka; Kono, Koichi; Tamaki, Junko

2016-09-01

The present risk assessment study of fluoride salts was conducted by oral administration of three different doses of sodium and potassium fluorides (NaF, KF) and zinc fluoride tetrahydrate (ZnF2 •4H2O) to male Wistar rats. The rats were divided into control and nine experimental groups, to which oral injections of 0.5 mL distilled water and 0.5 mL of fluoride solutions, respectively, were given. The dosage of fluoride compounds was adjusted to contain 2.1 mg (low-dose group, LG), 4.3 mg (mid-dose group, MG), and 5.4 mg fluoride per 200 g rat body weight (high-dose group, HG) corresponding to 5, 10, and 12.5 % of LD50 values for NaF. The 24-h urine volume, N-acetyl-β-D-glucosaminidase (NAG) and creatinine clearance (Ccr) were measured as markers of possible acute renal impact. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined in serum samples as markers of acute hepatic impact. The levels of serum and urinary fluoride were determined to evaluate fluoride bioavailability. The results reveal that higher doses of NaF, KF, and ZnF2 induced renal damage as indicated by higher urinary NAG (p < 0.05 with ≥90th percentile of control). High doses of ZnF2 also induced a significant Ccr decrease (p < 0.05 with ≤10th percentile of control). Low doses of NaF and mid-doses of ZnF2 induced polyuria (p < 0.05 with ≥90th percentile of control) while medium doses of NaF and low doses of KF also induced liver damage, as indicated by a high level of AST (p < 0.05 with ≥90th percentile of control). These findings suggest that oral administration of fluoride is a potential, dose-dependent risk factor of renal tubular damage.

A novel neutrophil-activating factor released by Trichomonas vaginalis.

PubMed Central

Shaio, M F; Lin, P R; Lee, C S; Hou, S C; Tang, P; Yang, K D

1992-01-01

We have investigated the effects of a novel neutrophil-activating factor released by Trichomonas vaginalis (TV-NAF) on neutrophil chemotaxis. TV-NAF was present in the supernatant from 10(7) T. vaginalis (STV) cultured in 1 ml of serum-free Hanks' balanced salt solution (HBSS) at 37 degrees C for 30 min. With a multichamber chemotactic assay, we found that there were 112 +/- 15 migrated neutrophils (mean +/- standard deviation, n = 7) for STV and 11 +/- 4 for HBSS per high-power field (x 400). STV was also able to induce neutrophil actin assembly (increased 1.5-fold), enhance expression of complement receptor type 3 (increased 5-fold), and promote intracellular calcium mobilization (increased 2.5-fold). There was no chemotactic activity in the preparation of STV from killed trichomonads. The fact that heating up to 100 degrees C or deproteinization by treatment with proteinase K at 65 degrees C for 1 h did not abolish its chemotactic activity suggests that the TV-NAF involved was not a protein. The chemotactic activity of TV-NAF was associated with the fraction containing small molecules of less than 3,000 Da. Therefore, the possibility that eicosanoid production by trichomonads is responsible for neutrophil activation was investigated. Leukotriene B4 (LTB4; 500 pg/ml) but not thromboxane B2 (< 20 pg/ml) or prostaglandin E2 (< 8 pg/ml) was found in the STV by radioimmunoassay. Production of LTB4 by trichomonads was time dependent and increased twofold when arachidonic acid (100 microM) was added but was not decreased when eicosanoid inhibitors were present. Evidence for the presence of LTB4 in STV was further provided by the fact that rabbit anti-LTB4 antiserum could abolish the chemotactic activity of STV. These studies suggest that the spontaneous release of TV-NAF, which is most likely LTB4, may activate neutrophils, presumably through a different arachidonate metabolic pathway than that in mammalian cells. PMID:1398962

Long term fault system reorganization of convergent and strike-slip systems

NASA Astrophysics Data System (ADS)

Cooke, M. L.; McBeck, J.; Hatem, A. E.; Toeneboehn, K.; Beyer, J. L.

2017-12-01

Laboratory and numerical experiments representing deformation over many earthquake cycles demonstrate that fault evolution includes episodes of fault reorganization that optimize work on the fault system. Consequently, the mechanical and kinematic efficiencies of fault systems do not increase monotonically through their evolution. New fault configurations can optimize the external work required to accommodate deformation, suggesting that changes in system efficiency can drive fault reorganization. Laboratory evidence and numerical results show that fault reorganization within accretion, strike-slip and oblique convergent systems is associated with increasing efficiency due to increased fault slip (frictional work and seismic energy) and commensurate decreased off-fault deformation (internal work and work against gravity). Between episodes of fault reorganization, fault systems may become less efficient as they produce increasing off fault deformation. For example, laboratory and numerical experiments show that the interference and interaction between different fault segments may increase local internal work or that increasing convergence can increase work against gravity produced by a fault system. This accumulation of work triggers fault reorganization as stored work provides the energy required to grow new faults that reorganize the system to a more efficient configuration. The results of laboratory and numerical experiments reveal that we should expect crustal fault systems to reorganize following periods of increasing inefficiency, even in the absence of changes to the tectonic regime. In other words, fault reorganization doesn't require a change in tectonic loading. The time frame of fault reorganization depends on fault system configuration, strain rate and processes that relax stresses within the crust. For example, stress relaxation may keep pace with stress accumulation, which would limit the increase in the internal work and gravitational work so that irregularities can persist along active fault systems without reorganization of the fault system. Consequently, steady state behavior, for example with constant fault slip rates, may arise either in systems with high degree of stress-relaxation or occur only within the intervals between episodes of fault reorganization.

Nonappropriated Fund Employees: Development of Revised NAF (Nonappropriated Fund) Employee Appraisal Form.

DTIC Science & Technology

1984-07-01

practices to ensure the health and well-being of self and co- workers . NAF 15 22. [MANAGERIAL ABILITY] The employee demonstrates the ability to plan...ABILITY] 21. The employee uses safe work practices to ensure the health and "- well-being of self and co- workers . [SAFETY MINDEDNESS] 22. The employee ...5 Outstanding COL COL APPRAISAL ITEMS 2 19. The employee uses safe work practices to ensure the health and well-being of self and co- workers . [SAFETY

Investigating the Role of Cyclin D1 in the Promotion of Genomic Instability and Breast Cancer

DTIC Science & Technology

2011-09-01

Tween-20, and protease/phosphatase inhibitors (1mM PMSF, 20U/mL aprotinin, 5mg/mL 12 leupeptin, 1mM DTT, 0.4mM NaF, and 10mM β- glycerophosphate ). Whole...inhibitors (1 mM PMSF, 20 U/ml aprotinin, 5 mg/ml leupeptin, 1 mM DTT, 0.4 mM NaF, and 10 mM b- glycerophosphate ), and protein concentration of samples was

Combinatorial investigation of the effects of sodium on Cu 2ZnSnSe4 polycrystalline thin films

NASA Astrophysics Data System (ADS)

Gibbs, Alex Hilton

Cu2ZnSnSe4 (CZTSe) possess highly suitable optical and electronic properties for use as an absorber layer in thin film solar cells. CZTSe also has potential to achieve terawatt level solar energy production due to its inexpensive and abundant material constituents. Currently, fabricating CZTSe devices with the expected theoretical performance has not been achieved, making the growth and formation of CZTSe an interesting topic of research. In this work, a two-step vacuum fabrication process consisting of RF co-sputtering followed by reactive annealing was explored as a viable technique for synthesizing CZTSe thin films. Furthermore, the enhancement of the fabrication process by the incorporation of sodium during annealing was studied using a combinatorial approach. Film composition was analyzed using electron dispersive spectroscopy. Structure, phase morphology, and formation were determined using scanning electron microscopy, x-ray diffraction, atomic force microscopy and raman spectroscopy. Optical and electronic properties were characterized using UV-Vis and Voc were measurements under a one sun solar simulator. RF co-sputtering CuSe, ZnSe, and SnSe precursors produced films with good thickness uniformity, adhesion and stoichiometry control over 3 x 3 in 2 substrates. Composition measurements showed that the precursor films maintained stability during an annealing process of 580° C for 20 minutes producing near stoichiometric CZTSe. However, grain size was small with an average diameter of 350 nm. The CZTSe film produced by this process exhibited a suitable absorption coefficient of > 104 cm-1 and aband gap near 1.0 eV. The film also produced an XRD pattern consistent with tetragonal CZTSe with no secondary phase formation with the exception of approximately 12.5 nm of interfacial MoSe2 formation at the back contact. The combinatorial investigation of the influence of sodium on CZTSe growth and morphology was achieved using a custom built constant withdraw shutter to evaporate NaF with a 0-60 nm thickness spread on the substrate prior to precursor sputtering. This experiment showed that the incorporation of NaF did enhance grain size; however, there was little correlation with initial NaF composition observed. It is concluded that NaF undergoes high degree of vapor transport and readily distributes nonuniformly throughout the film during the annealing process and also potentially escapes the annealing environment if not properly contained. An experiment on achieving Na incorporation by diffusion from a soda lime glass substrate resulted in a far more uniform enhancement of grain growth. The experiment also revealed that NaF greatly reduced precursor film adhesion to the substrate due to the hygroscopic nature of NaF. X-ray diffraction measurements also showed that the addition of the NaF layer was could potentially suppress the formation of MoSe2.

Earthquake and Tsunami Disaster Mitigation in the Marmara Region and Disaster Education in Turkey Part3

NASA Astrophysics Data System (ADS)

Kaneda, Yoshiyuki; Ozener, Haluk; Meral Ozel, Nurcan; Kalafat, Dogan; Ozgur Citak, Seckin; Takahashi, Narumi; Hori, Takane; Hori, Muneo; Sakamoto, Mayumi; Pinar, Ali; Oguz Ozel, Asim; Cevdet Yalciner, Ahmet; Tanircan, Gulum; Demirtas, Ahmet

2017-04-01

There have been many destructive earthquakes and tsunamis in the world.The recent events are, 2011 East Japan Earthquake/Tsunami in Japan, 2015 Nepal Earthquake and 2016 Kumamoto Earthquake in Japan, and so on. And very recently a destructive earthquake occurred in Central Italy. In Turkey, the 1999 Izmit Earthquake as the destructive earthquake occurred along the North Anatolian Fault (NAF). The NAF crosses the Sea of Marmara and the only "seismic gap" remains beneath the Sea of Marmara. Istanbul with high population similar to Tokyo in Japan, is located around the Sea of Marmara where fatal damages expected to be generated as compound damages including Tsunami and liquefaction, when the next destructive Marmara Earthquake occurs. The seismic risk of Istanbul seems to be under the similar risk condition as Tokyo in case of Nankai Trough earthquake and metropolitan earthquake. It was considered that Japanese and Turkish researchers can share their own experiences during past damaging earthquakes and can prepare for the future large earthquakes in cooperation with each other. Therefore, in 2013 the two countries, Japan and Turkey made an agreement to start a multidisciplinary research project, MarDiM SATREPS. The Project runs researches to aim to raise the preparedness for possible large-scale earthquake and Tsunami disasters in Marmara Region and it has four research groups with the following goals. 1) The first one is Marmara Earthquake Source region observational research group. This group has 4 sub-groups such as Seismicity, Geodesy, Electromagnetics and Trench analyses. Preliminary results such as seismicity and crustal deformation on the sea floor in Sea of Marmara have already achieved. 2) The second group focuses on scenario researches of earthquake occurrence along the North Anatolia Fault and precise tsunami simulation in the Marmara region. Research results from this group are to be the model of earthquake occurrence scenario in Sea of Marmara and the case studies with advanced tsunami simulation for measure cities. 3) Aims of the third group are improvements and constructions of seismic characterizations and damage predictions based on observation researches and precise simulations. Research results from this group will be very important for disaster measures. 4) The fourth group is promoting disaster educations using research result visuals. The mission of this group is very important for information dissemination and practical and effective disaster education in Turkey. The research results from all components will be integrated and utilized for disaster mitigation in Marmara region and disaster education in Turkey. Updated research results of the MarDiM SATREPS Project will be officially presented toward the end of the Project period, which is March 2018.

Low glucose utilization and neurodegenerative changes caused by sodium fluoride exposure in rat's developmental brain.

PubMed

Jiang, Chunyang; Zhang, Shun; Liu, Hongliang; Guan, Zhizhong; Zeng, Qiang; Zhang, Cheng; Lei, Rongrong; Xia, Tao; Wang, Zhenglun; Yang, Lu; Chen, Yihu; Wu, Xue; Zhang, Xiaofei; Cui, Yushan; Yu, Linyu; Wang, Aiguo

2014-03-01

Fluorine, a toxic and reactive element, is widely prevalent throughout the environment and can induce toxicity when absorbed into the body. This study was to explore the possible mechanisms of developmental neurotoxicity in rats treated with different levels of sodium fluoride (NaF). The rats' intelligence, as well as changes in neuronal morphology, glucose absorption, and functional gene expression within the brain were determined using the Morris water maze test, transmission electron microscopy, small-animal magnetic resonance imaging and Positron emission tomography and computed tomography, and Western blotting techniques. We found that NaF treatment-impaired learning and memory in these rats. Furthermore, NaF caused neuronal degeneration, decreased brain glucose utilization, decreased the protein expression of glucose transporter 1 and glial fibrillary acidic protein, and increased levels of brain-derived neurotrophic factor in the rat brains. The developmental neurotoxicity of fluoride may be closely associated with low glucose utilization and neurodegenerative changes.

Predeployment validation of fault-tolerant systems through software-implemented fault insertion

NASA Technical Reports Server (NTRS)

Czeck, Edward W.; Siewiorek, Daniel P.; Segall, Zary Z.

1989-01-01

Fault injection-based automated testing (FIAT) environment, which can be used to experimentally characterize and evaluate distributed realtime systems under fault-free and faulted conditions is described. A survey is presented of validation methodologies. The need for fault insertion based on validation methodologies is demonstrated. The origins and models of faults, and motivation for the FIAT concept are reviewed. FIAT employs a validation methodology which builds confidence in the system through first providing a baseline of fault-free performance data and then characterizing the behavior of the system with faults present. Fault insertion is accomplished through software and allows faults or the manifestation of faults to be inserted by either seeding faults into memory or triggering error detection mechanisms. FIAT is capable of emulating a variety of fault-tolerant strategies and architectures, can monitor system activity, and can automatically orchestrate experiments involving insertion of faults. There is a common system interface which allows ease of use to decrease experiment development and run time. Fault models chosen for experiments on FIAT have generated system responses which parallel those observed in real systems under faulty conditions. These capabilities are shown by two example experiments each using a different fault-tolerance strategy.

NaF-loaded core-shell PAN-PMMA nanofibers as reinforcements for Bis-GMA/TEGDMA restorative resins.

PubMed

Cheng, Liyuan; Zhou, Xuegang; Zhong, Hong; Deng, Xuliang; Cai, Qing; Yang, Xiaoping

2014-01-01

A kind of core-shell nanofibers containing sodium fluoride (NaF) was produced and used as reinforcing materials for dimethacrylate-based dental restorative resins in this study. The core-shell nanofibers were prepared by coaxial-electrospinning with polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA) solutions as core and shell fluids, respectively. The produced PAN-PMMA nanofibers varied in fiber diameter and the thickness of PMMA shell depending on electrospinning parameters. NaF-loaded nanofibers were obtained by incorporating NaF nanocrystals into the core fluid at two loadings (0.8 or 1.0wt.%). Embedment of NaF nanocrystals into the PAN core did not damage the core-shell structure. The addition of PAN-PMMA nanofibers into Bis-GMA/TEGDMA clearly showed the reinforcement due to the good interfacial adhesion between fibers and resin. The flexural strength (Fs) and flexural modulus (Ey) of the composites decreased slightly as the thickness of PMMA shell increasing. Sustained fluoride releases with minor initial burst release were achieved from NaF-loaded core-shell nanofibers and the corresponding composites, which was quite different from the case of embedding NaF nanocrystals into the dental resin directly. The study demonstrated that NaF-loaded PAN-PMMA core-shell nanofibers were not only able to improve the mechanical properties of restorative resin, but also able to provide sustained fluoride release to help in preventing secondary caries. © 2013.

The engine fuel system fault analysis

NASA Astrophysics Data System (ADS)

Zhang, Yong; Song, Hanqiang; Yang, Changsheng; Zhao, Wei

2017-05-01

For improving the reliability of the engine fuel system, the typical fault factor of the engine fuel system was analyzed from the point view of structure and functional. The fault character was gotten by building the fuel system fault tree. According the utilizing of fault mode effect analysis method (FMEA), several factors of key component fuel regulator was obtained, which include the fault mode, the fault cause, and the fault influences. All of this made foundation for next development of fault diagnosis system.

Electrochemical and Spectroscopic Studies of Molten Halides

DTIC Science & Technology

1993-01-08

industry and in the construction of electrical and electronic devices. In 1965, Mellors and Senderoff [1] introduced a general method for obtaining pure...illustrate the complexity of homogeneous Fischer - Tropsch catalysis in chloroaluminate melts and partially explain the differences observed in the...system NaAICI4-NaF has been determined using differential thermal analysis (DTA). This method results in temperatures at which endothermic and

A distributed fault-detection and diagnosis system using on-line parameter estimation

NASA Technical Reports Server (NTRS)

Guo, T.-H.; Merrill, W.; Duyar, A.

1991-01-01

The development of a model-based fault-detection and diagnosis system (FDD) is reviewed. The system can be used as an integral part of an intelligent control system. It determines the faults of a system from comparison of the measurements of the system with a priori information represented by the model of the system. The method of modeling a complex system is described and a description of diagnosis models which include process faults is presented. There are three distinct classes of fault modes covered by the system performance model equation: actuator faults, sensor faults, and performance degradation. A system equation for a complete model that describes all three classes of faults is given. The strategy for detecting the fault and estimating the fault parameters using a distributed on-line parameter identification scheme is presented. A two-step approach is proposed. The first step is composed of a group of hypothesis testing modules, (HTM) in parallel processing to test each class of faults. The second step is the fault diagnosis module which checks all the information obtained from the HTM level, isolates the fault, and determines its magnitude. The proposed FDD system was demonstrated by applying it to detect actuator and sensor faults added to a simulation of the Space Shuttle Main Engine. The simulation results show that the proposed FDD system can adequately detect the faults and estimate their magnitudes.

A three-year clinical comparison of a sodium monofluorophosphate dentifrice with sodium fluoride dentifrices on dental caries in children.

PubMed

Lu, K H; Ruhlman, C D; Chung, K L; Sturzenberger, O P; Lehnhoff, R W

1987-01-01

This study compared the anticaries effects of these three fluoride-containing dentifrices: 1100 ppm F as NaF (positive control); 2800 ppm F as SMFP; and 2800 ppm F as NaF. The group using the 2800 SMFP dentifrice showed no significant differences in DMFS or DMFT, compared to the positive control, at anytime during the study. This indicated that higher levels of sodium monofluorophosphate in a dentifrice offer no advantage in caries protection over the conventional level of sodium fluoride, 1100 ppm F.

Dyskeratosis congenita mutations in the H/ACA domain of human telomerase RNA affect its assembly into a pre-RNP

PubMed Central

Trahan, Christian; Dragon, François

2009-01-01

Dyskeratosis congenita (DC) is an inherited disorder that implicates defects in the biology of telomeres, which are maintained by telomerase, a ribonucleoprotein with reverse transcriptase activity. Like all H/ACA RNAs, the H/ACA domain of nascent human telomerase RNA (hTR) forms a pre-RNP with H/ACA proteins NAF1, dyskerin, NOP10, and NHP2 in vivo. To assess the pre-RNP assembly of hTR mutants that poorly accumulate in vivo, we developed an in vitro system that uses components of human origin. Pre-RNPs were reconstituted with synthetic 32P-labeled RNAs and 35S-labeled proteins produced in rabbit reticulocyte lysate, and immunoprecipitations were carried out to analyze RNP formation. We show that human NAF1 cannot bind directly to the H/ACA domain of hTR, and requires the core trimer dyskerin-NOP10-NHP2 to be efficiently incorporated into the pre-RNP. This order of assembly seems common to H/ACA RNAs since it was observed with snoRNA ACA36 and scaRNA U92, which are predicted to guide pseudouridylation of 18S rRNA and U2 snRNA, respectively. However, the processing H/ACA snoRNA U17 did not conform to this rule, as NAF1 alone was able to bind it. We also provide the first evidence that DC-related mutations of hTR C408G and Δ378-451 severely impair pre-RNP assembly. Integrity of boxes H and ACA of hTR are also crucial for pre-RNP assembly, while the CAB box is dispensable. Our results offer new insights into the defects caused by some mutations located in the H/ACA domain of hTR. PMID:19095616

[The effect of alternating administration of aluminum chloride and sodium fluoride in drinking water on the concentration of fluoride in serum and its content in bones of rats].

PubMed

Lubkowska, Anna; Chlubek, Dariusz; Machoy-Mokrzyniska, Anna

2006-01-01

Fluorine and aluminum remain a very interesting research topic due to equivocal and relatively unknown toxic action, role in the etiology of various diseases, and interactions of both elements. Fluorine and aluminum compounds are absorbed by organisms through the gastric and respiratory systems, although the latter route operates only at very high concentrations in air. Chronic exposure to fluorine and aluminum leads to accumulation of both elements, especially in bones and teeth, but also in lung, brain, kidney, and liver. Organisms excrete these elements with urine, faeces, and to a minor extent with sweat and bile. In the light of reports suggesting that aluminum has protective properties against fluorine toxicity during exposure to both elements, we decided to examine the effect of alternating doses of aluminum fluoride and sodium fluoride in drinking water on rats. Four female groups received: I--100 ppm fluorine ions during one month; II--100 ppm fluorine ions alternating every two days with 300 ppm aluminum ions during one month; III--100 ppm fluoride ions during four months; IV--100 ppm fluorine ions alternating every two days with 300 ppm aluminum ions during four months. The respective male groups called IA, IIA, IIIA, and IVA were treated identically. Subsequently, the animals were anesthetized and sacrificed. Blood was sampled from the heart and the right femur was removed for fluorine determination. Fluorine content in the femur and serum was determined with an ion-selective electrode (Orion). The results were analyzed statistically (Statistica 6). We observed higher fluoride concentrations in serum as compared with control values in all groups of female and male rats exposed to sodium fluoride only. Longer exposure time (4 months) did not result in further increase in serum fluoride concentration. However, longer exposure increased fluoride accumulation in the femur (p < 0.001). All groups exposed to NaF had significantly higher fluoride concentration in the femur as compared with control animals. Groups receiving NaF and AlCl3 showed lower fluoride concentration in serum and femur compared with those exposed to NaF only and higher in comparison with controls. Fluorine content in the femur of rats exposed to NaF and AlCI3 for four months was similar to the results obtained after one month of exposure.

Zero-gravity growth of NaF-NaCl eutectics in the NASA Skylab program

NASA Technical Reports Server (NTRS)

Yue, A. S.; Allen, F. G.; Yu, J. G.

1976-01-01

Continuous and discontinuous NaF fibers, embedded in a NaCl matrix, were produced in space and on earth. The production of continuous fibers in a eutectic mixture is attributed to the absence of convection current in the liquid during solidification in space. Image transmission and optical transmittance measurements of transverse sections of the space-grown and earth-grown ingots were made with a light microscope and a spectrometer. It is shown that better optical properties were obtained from samples grown in space. This was attributed to a better alignment of NaF fibers along the ingot axis. A new concept is advanced to explain the phenomenon of transmittance versus far infrared wavelength of the directionally solidified NaCl-NaF eutectic in terms of the two-dimensional Bragg Scattering and the polarization effect of Rayleigh scattering. This concept can be applied to other eutectic systems as long as the index of refraction of the matrix over a range of wavelengths is known. Experimental data are in agreement with the theoretical prediction.

WE-FG-202-05: Quantification of Bone Flare On [F-18] NaF PET/CT in Metastatic Prostate Cancer

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

Weisman, A; Harmon, S; Perk, T

Purpose: Bone flare has been observed on Tc-99m bone scans during early assessment in metastatic Castration-Resistant Prostate Cancer (mCRPC) patients receiving select androgen-signaling pathway (AR) targeted treatments, including CYP17-inhibitor Abiraterone. This study investigates the appearance and potential clinical impact of bone flare in mCRPC patients receiving CYP17-inhibitors using {sup 18}F-NaF PET/CT. Methods: Twenty-three mCRPC patients being treated with CYP17-inhibitors received NaF PET/CT scans at baseline, week 6, and week 12 of treatment. Individual lesions were identified using a SUV>15 threshold within skeletal regions and articulated bone registration was used to track lesions between scans. Standard SUV metrics were extracted globallymore » for each patient (pSUV) and for each individual lesion (iSUV). Differences in metrics across time-points were compared using Wilcoxon signed-rank tests. Cox proportional hazard regression analyses were conducted between global metrics and progression-free survival (PFS). Results: Nineteen patients (83%) showed increasing NaF PET global metrics at week 6, with pSUV{sub total} reflecting consensus change across other global metrics with median increase +33% (range +2 to 205%). Of these patients, 14 showed subsequent decrease in pSUV{sub total}, with a median of −17% (range −76 to −1%), indicating flare phenomenon. Increasing pSUV{sub mean} at week 6 correlated with extended clinical PFS (HR = 0.58, p=0.02). New lesions did not account for the initial increase in global NaF metrics. Lesion-level analysis reveals 316 lesions in the 14 patients exhibiting global flare. On average, 75% (sd: 22%) of lesions follow global trends with iSUV{sub total} increasing at week 6 and 65% (sd: 17%) showing iSUV{sub total} decrease at week 12. Conclusion: Bone flare was detected on NaF PET/CT in the first 6 weeks of treatment for mCRPC patients receiving CYP17-inhibitors, subsiding by week 12. Characterization provided in this study suggests prolonged PFS in patients showing bone flare early in select AR-directed treatments. Prostate Cancer Foundation.« less

Remineralization effect of CPP-ACP and fluoride for white spot lesions in vitro.

PubMed

Oliveira, Gustavo M S; Ritter, André V; Heymann, Harald O; Swift, Edward; Donovan, Terry; Brock, Guy; Wright, Tim

2014-12-01

This in vitro study compared the remineralization effect on white spot lesions of casein phosphopeptide-amorphous calcium phosphate crème, or CPP-ACP (MI Paste™), 1.1% NaF dentifrice containing 5000ppm of fluoride (ControlRX™), or CPP-ACP crème with 900ppm of fluoride (MI Paste Plus™) with that of a control. Artificial white spot lesions were created on smooth enamel surfaces of sound molars using a previously reported demineralization model. Specimens were randomly assigned to four treatments (n=35) with a pH-cycling model over 30 days: Control (no treatment); MI Paste (10% CPP-ACP crème); F5000 (1.1% NaF dentifrice); or MI Paste Plus (10% CPP-ACP plus 900ppm fluoride crème). Products were applied following manufacturers' directions. Changes in mean lesion depth expressed by percent fluorescence loss (ΔF%), and lesion area (mm(2)) from baseline to after treatment were measured with light-induced fluorescence (QLF). Mean values of each parameter were compared between groups (p<0.05). The remineralization pattern for the F5000 group was unique with marked initial remineralization during the first 10 days and little subsequent change. Based on mean lesion area, the F5000 demonstrated greater remineralization than Control, MI Paste and MI Paste Plus groups. Based on mean fluorescence loss, the F5000 group showed improved remineralization relative to MI Paste Plus, but did not differ statistically from the Control at the end of 30 days. The 1.1% NaF dentifrice demonstrated overall greater remineralization ability than 10% CPP-ACP crème. However, the 1.1% NaF dentifrice was only as effective as the Control to reduce fluorescence loss. This study showed that a 1.1% NaF dentifrice (5000ppm) demonstrated greater remineralization ability than the CPP-ACP topical tooth crème and that the addition of fluoride to its formulation seems to enhance remineralization. Saliva also has the ability to exert an important remineralization effect over time. Copyright © 2014 Elsevier Ltd. All rights reserved.

TU-AB-BRA-05: Repeatability of [F-18]-NaF PET Imaging Biomarkers for Bone Lesions: A Multicenter Study

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

Lin, C; Bradshaw, T; Perk, T

2015-06-15

Purpose: Quantifying the repeatability of imaging biomarkers is critical for assessing therapeutic response. While therapeutic efficacy has been traditionally quantified by SUV metrics, imaging texture features have shown potential for use as quantitative biomarkers. In this study we evaluated the repeatability of quantitative {sup 18}F-NaF PET-derived SUV metrics and texture features in bone lesions from patients in a multicenter study. Methods: Twenty-nine metastatic castrate-resistant prostate cancer patients received whole-body test-retest NaF PET/CT scans from one of three harmonized imaging centers. Bone lesions of volume greater than 1.5 cm{sup 3} were identified and automatically segmented using a SUV>15 threshold. From eachmore » lesion, 55 NaF PET-derived texture features (including first-order, co-occurrence, grey-level run-length, neighbor gray-level, and neighbor gray-tone difference matrix) were extracted. The test-retest repeatability of each SUV metric and texture feature was assessed with Bland-Altman analysis. Results: A total of 315 bone lesions were evaluated. Of the traditional SUV metrics, the repeatability coefficient (RC) was 12.6 SUV for SUVmax, 2.5 SUV for SUVmean, and 4.3 cm{sup 3} for volume. Their respective intralesion coefficients of variation (COVs) were 12%, 17%, and 6%. Of the texture features, COV was lowest for entropy (0.03%) and highest for kurtosis (105%). Lesion intraclass correlation coefficient (ICC) was lowest for maximum correlation coefficient (ICC=0.848), and highest for entropy (ICC=0.985). Across imaging centers, repeatability of texture features and SUV varied. For example, across imaging centers, COV for SUVmax ranged between 11–23%. Conclusion: Many NaF PET-derived SUV metrics and texture features for bone lesions demonstrated high repeatability, such as SUVmax, entropy, and volume. Several imaging texture features demonstrated poor repeatability, such as SUVtotal and SUVstd. These results can be used to establish response criteria for NaF PET-based treatment response assessment. Prostate Cancer Foundation (PCF)« less

Data-driven simultaneous fault diagnosis for solid oxide fuel cell system using multi-label pattern identification

NASA Astrophysics Data System (ADS)

Li, Shuanghong; Cao, Hongliang; Yang, Yupu

2018-02-01

Fault diagnosis is a key process for the reliability and safety of solid oxide fuel cell (SOFC) systems. However, it is difficult to rapidly and accurately identify faults for complicated SOFC systems, especially when simultaneous faults appear. In this research, a data-driven Multi-Label (ML) pattern identification approach is proposed to address the simultaneous fault diagnosis of SOFC systems. The framework of the simultaneous-fault diagnosis primarily includes two components: feature extraction and ML-SVM classifier. The simultaneous-fault diagnosis approach can be trained to diagnose simultaneous SOFC faults, such as fuel leakage, air leakage in different positions in the SOFC system, by just using simple training data sets consisting only single fault and not demanding simultaneous faults data. The experimental result shows the proposed framework can diagnose the simultaneous SOFC system faults with high accuracy requiring small number training data and low computational burden. In addition, Fault Inference Tree Analysis (FITA) is employed to identify the correlations among possible faults and their corresponding symptoms at the system component level.

Fault detection and isolation for complex system

NASA Astrophysics Data System (ADS)

Jing, Chan Shi; Bayuaji, Luhur; Samad, R.; Mustafa, M.; Abdullah, N. R. H.; Zain, Z. M.; Pebrianti, Dwi

2017-07-01

Fault Detection and Isolation (FDI) is a method to monitor, identify, and pinpoint the type and location of system fault in a complex multiple input multiple output (MIMO) non-linear system. A two wheel robot is used as a complex system in this study. The aim of the research is to construct and design a Fault Detection and Isolation algorithm. The proposed method for the fault identification is using hybrid technique that combines Kalman filter and Artificial Neural Network (ANN). The Kalman filter is able to recognize the data from the sensors of the system and indicate the fault of the system in the sensor reading. Error prediction is based on the fault magnitude and the time occurrence of fault. Additionally, Artificial Neural Network (ANN) is another algorithm used to determine the type of fault and isolate the fault in the system.

Job-Grading System Manual for Nonappropriated Fund Instrumentalities

DTIC Science & Technology

1981-10-01

rationale for use and forwarded through designated channels to the office of DoD NAF Personnel Policy. E. USE OF OPM POSITION CLASSIFICATION AND JOB...marking, building and control of campfires, and identification of hazardous plants and animals. Schedules day or longer "camp-outs," publicizes the...Merchandisers PS-5 decorate designated areas, including showcases, ledges, and fixtures. Incumbents set up focal displays near entrances to attract cus

Analysis of a hardware and software fault tolerant processor for critical applications

NASA Technical Reports Server (NTRS)

Dugan, Joanne B.

1993-01-01

Computer systems for critical applications must be designed to tolerate software faults as well as hardware faults. A unified approach to tolerating hardware and software faults is characterized by classifying faults in terms of duration (transient or permanent) rather than source (hardware or software). Errors arising from transient faults can be handled through masking or voting, but errors arising from permanent faults require system reconfiguration to bypass the failed component. Most errors which are caused by software faults can be considered transient, in that they are input-dependent. Software faults are triggered by a particular set of inputs. Quantitative dependability analysis of systems which exhibit a unified approach to fault tolerance can be performed by a hierarchical combination of fault tree and Markov models. A methodology for analyzing hardware and software fault tolerant systems is applied to the analysis of a hypothetical system, loosely based on the Fault Tolerant Parallel Processor. The models consider both transient and permanent faults, hardware and software faults, independent and related software faults, automatic recovery, and reconfiguration.

[Experimental study on fas expression of spermatogenic cell in male rats induced by fluorine].

PubMed

Xu, Rui; Shang, Weichao; Liu, Jianmin; Cheng, Xuemin; Ba, Yue; Huang, Hui; Cui, Liuxin

2010-05-01

To research the effect of fluorine on the expression of Fas protein, then study the mechanism of male reproductive toxicity induced by fluoride on molecular level. Thirty Wistar male rats were divided into control group, low-dose group and high-dose group. The NaF dosage for every group were 0,2 and 4g/L. The content of NaF in testis was measured by using fluorine selective electrode. Changes of testosterone and Fas protein were observed using the methods of radioimmunoassay, in situ hybridization. In addition, we observed the quality of spermatozoa. The testis fluoride content of two fluorine treatment groups were higher than that of control group (P < 0.05), and had a dose-dependent effect. The level of testosterone, the number and the livability of the spermatozoon in fluorotic groups were lower than those of control rats (P < 0.05), and the above indexes decreased with the incrase of dosage. The expression of Fas in spermatogenic cells and the sperm aberration of each fluorotic group were higher than control group (P < 0.05), both of them increased with the increase of dosage. Fluorin could reduce the level of serum testosterone, then activated the Fas/FasL system, which caused damage to the reprodutive system.

X-ray photoelectron spectroscopy as detection tool for coordinated or uncoordinated fluorine atoms demonstrated on fluoride systems NaF, K2TaF7, K3TaF8, K2ZrF6, Na7Zr6F31 and K3ZrF7

NASA Astrophysics Data System (ADS)

Boča, Miroslav; Barborík, Peter; Mičušík, Matej; Omastová, Mária

2012-07-01

While systems K3TaF8 and K3ZrF7 were prepared by modified molten salt method modified wet pathway was used for reproducible preparation of Na7Zr6F31. Its congruently melting character was demonstrated on simultaneous TG/DSC measurements and XRD patterns. X-ray photoelectron spectroscopy was applied for identification of differently bonded fluorine atoms in series of compounds NaF, K2TaF7, K3TaF8, K2ZrF6, Na7Zr6F31 and K3ZrF7. Three different types of fluorine atoms were described qualitatively and quantitatively. Uncoordinated fluorine atoms (F-) provide signals at lowest binding energies, followed by signals from terminally coordinated fluorine atoms (M-F) and then bridging fluorine atoms (M-F-M) at highest energy. Based on XPS F 1s signals assigned to fluorine atoms in compounds with correctly determined structure it was suggested that fluorine atoms in K3ZrF7 have partially bridging character.

Dendritic sodium channels promote active decorrelation and reduce phase locking to parkinsonian input oscillations in model globus pallidus neurons

PubMed Central

Edgerton, Jeremy R.; Jaeger, Dieter

2011-01-01

Correlated firing among populations of neurons is present throughout the brain and is often rhythmic in nature, observable as an oscillatory fluctuation in the local field potential. Although rhythmic population activity is believed to be critical for normal function in many brain areas, synchronized neural oscillations are associated with disease states in other cases. In the globus pallidus (GP in rodents, homolog of the primate GPe), pairs of neurons generally have uncorrelated firing in normal animals despite an anatomical organization suggesting that they should receive substantial common input. By contrast, correlated and rhythmic GP firing is observed in animal models of Parkinson's disease (PD). Based in part on these findings it has been proposed that an important part of basal ganglia function is active decorrelation, whereby redundant information is compressed. Mechanisms that implement active decorrelation, and changes that cause it to fail in PD, are subjects of great interest. Rat GP neurons express fast, transient voltage-dependent sodium channels (NaF channels) in their dendrites, with the expression level being highest near asymmetric synapses. We recently showed that the dendritic NaF density strongly influences the responsiveness of model GP neurons to synchronous excitatory inputs. In the present study we use rat GP neuron models to show that dendritic NaF channel expression is a potential cellular mechanism of active decorrelation. We further show that model neurons with lower dendritic NaF channel expression have a greater tendency to phase lock with oscillatory synaptic input patterns like those observed in PD. PMID:21795543

Effects of perinatal fluoride exposure on the expressions of miR-124 and miR-132 in hippocampus of mouse pups.

PubMed

Wang, Jixiang; Zhang, Yuliang; Guo, Zhenzhen; Li, Rui; Xue, Xingchen; Sun, Zilong; Niu, Ruiyan

2018-04-01

To investigate the effects of perinatal fluoride exposure on learning and memory ability of mouse offspring, ICR female mice were received different doses of sodium fluoride (0, 25, 50, 100 mg/L NaF) from pregnant day 7 to lactational day 21. Pups were exposed to fluoride through the cord blood and breast milk. Open field test showed that compared to the control group, perinatal fluoride exposure significantly decreased the number of entries into the center zone in 100 mg/L NaF group. In the eight-arm maze test, the number of working memory errors, reference memory errors, and the total arm entries were significantly increased in fluoride treatment groups, compared to the control group. Additionally, 100 mg/L NaF significantly elevated the expression levels of miR-124, miR-132, and DiGeorge syndrome chromosomal region 8 (DGCR8) in hippocampus of mouse pups at postnatal day (PND) 21. Contrarily, methyl CpG binding protein 2 (MeCP2) were dramatically reduced in 50 and 100 mg/L NaF groups, while cAMP-response element binding protein (CREB) mRNA level was significantly decreased in all fluoride groups. These findings suggested that the impairment of learning and memory in mouse offspring induced by perinatal fluoride exposure may partly result from the enhanced miR-124 and miR-132 and the alterations of their target genes. Copyright © 2018 Elsevier Ltd. All rights reserved.

Five ab initio potential energy and dipole moment surfaces for hydrated NaCl and NaF. I. Two-body interactions.

PubMed

Wang, Yimin; Bowman, Joel M; Kamarchik, Eugene

2016-03-21

We report full-dimensional, ab initio-based potentials and dipole moment surfaces for NaCl, NaF, Na(+)H2O, F(-)H2O, and Cl(-)H2O. The NaCl and NaF potentials are diabatic ones that dissociate to ions. These are obtained using spline fits to CCSD(T)/aug-cc-pV5Z energies. In addition, non-linear least square fits using the Born-Mayer-Huggins potential are presented, providing accurate parameters based strictly on the current ab initio energies. The long-range behavior of the NaCl and NaF potentials is shown to go, as expected, accurately to the point-charge Coulomb interaction. The three ion-H2O potentials are permutationally invariant fits to roughly 20,000 coupled cluster CCSD(T) energies (awCVTZ basis for Na(+) and aVTZ basis for Cl(-) and F(-)), over a large range of distances and H2O intramolecular configurations. These potentials are switched accurately in the long range to the analytical ion-dipole interactions, to improve computational efficiency. Dipole moment surfaces are fits to MP2 data; for the ion-ion cases, these are well described in the intermediate- and long-range by the simple point-charge expression. The performance of these new fits is examined by direct comparison to additional ab initio energies and dipole moments along various cuts. Equilibrium structures, harmonic frequencies, and electronic dissociation energies are also reported and compared to direct ab initio results. These indicate the high fidelity of the new PESs.

Effect of fluoride and chlorhexidine digluconate mouthrinses on plaque biofilms.

PubMed

Rabe, Per; Twetman, Svante; Kinnby, Bertil; Svensäter, Gunnel; Davies, Julia R

2015-01-01

To develop a model in which to investigate the architecture of plaque biofilms formed on enamel surfaces in vivo and to compare the effects of anti-microbial agents of relevance for caries on biofilm vitality. Materials and Methodology : Enamel discs mounted on healing abutments in the pre-molar region were worn by three subjects for 7 days. Control discs were removed before subjects rinsed with 0.1% chlorhexidine digluconate (CHX) or 0.2% sodium fluoride (NaF) for 1 minute. Biofilms were stained with Baclight Live/Dead and z-stacks of images created using confocal scanning laser micoscopy. The levels of vital and dead/damaged bacteria in the biofilms, assessed as the proportion of green and red pixels respectively, were analysed using ImageTrak(®) software. Results : The subjects showed individual differences in biofilm architecture. The thickness of the biofilms varied from 28-96µm although cell density was always the greatest in the middle layers. In control biofilms, the overall levels of vitality were high (71-98%) especially in the area closest to the enamel interface. Rinsing with either CHX or NaF caused a similar reduction in overall vitality. CHX exerted an effect throughout the biofilm, particularly on the surface of cell clusters whereas NaF caused cell damage/death mainly in the middle to lower biofilm layers. Conclusion : We describe a model that allows the formation of mature, undisturbed oral biofilms on human enamel surfaces in vivo and show that CHX and NaF have a similar effect on overall vitality but differ in their sites of action.

Diabetes Diminishes the Portal-Systemic Collateral Vascular Response to Vasopressin via Vasopressin Receptor and Gα Proteins Regulations in Cirrhotic Rats

PubMed Central

Lee, Jing-Yi; Huo, Teh-Ia; Wang, Sun-Sang; Lin, Han-Chieh; Chuang, Chiao-Lin; Lee, Shou-Dong

2013-01-01

Liver cirrhosis may lead to portal-systemic collateral formation and bleeding. The hemostatic effect is influenced by the response of collateral vessels to vasoconstrictors. Diabetes and glucose also influence vasoresponsiveness, but their net effect on collaterals remains unexplored. This study investigated the impact of diabetes or glucose application on portal-systemic collateral vasoresponsiveness to arginine vasopressin (AVP) in cirrhosis. Spraque-Dawley rats with bile duct ligation (BDL)-induced cirrhosis received vehicle (citrate buffer) or streptozotocin (diabetic, BDL/STZ). The in situ collateral perfusion was done after hemodynamic measurements: Both were perfused with Krebs solution, D-glucose, or D-glucose and NaF, with additional OPC-31260 for the BDL/STZ group. Splenorenal shunt vasopressin receptors and Gα proteins mRNA expressions were evaluated. The survival rate of cirrhotic rats was decreased by STZ injection. The collateral perfusion pressure changes to AVP were lower in STZ-injected groups, which were reversed by OPC-31260 (a V2R antagonist) and overcome by NaF (a G protein activator). The splenorenal shunt V2R mRNA expression was increased while Gα proteins mRNA expressions were decreased in BDL/STZ rats compared to BDL rats. The Gαq and Gα11 mRNA expressions also correlated with the maximal perfusion pressure changes to AVP. Diabetes diminished the portal-systemic collateral vascular response to AVP in rats with BDL-induced cirrhosis, probably via V2 receptor up-regulation and Gα proteins down-regulation. PMID:23874439

Diabetes diminishes the portal-systemic collateral vascular response to vasopressin via vasopressin receptor and Gα proteins regulations in cirrhotic rats.

PubMed

Lee, Jing-Yi; Huo, Teh-Ia; Wang, Sun-Sang; Huang, Hui-Chun; Lee, Fa-Yauh; Lin, Han-Chieh; Chuang, Chiao-Lin; Lee, Shou-Dong

2013-01-01

Liver cirrhosis may lead to portal-systemic collateral formation and bleeding. The hemostatic effect is influenced by the response of collateral vessels to vasoconstrictors. Diabetes and glucose also influence vasoresponsiveness, but their net effect on collaterals remains unexplored. This study investigated the impact of diabetes or glucose application on portal-systemic collateral vasoresponsiveness to arginine vasopressin (AVP) in cirrhosis. Spraque-Dawley rats with bile duct ligation (BDL)-induced cirrhosis received vehicle (citrate buffer) or streptozotocin (diabetic, BDL/STZ). The in situ collateral perfusion was done after hemodynamic measurements: Both were perfused with Krebs solution, D-glucose, or D-glucose and NaF, with additional OPC-31260 for the BDL/STZ group. Splenorenal shunt vasopressin receptors and Gα proteins mRNA expressions were evaluated. The survival rate of cirrhotic rats was decreased by STZ injection. The collateral perfusion pressure changes to AVP were lower in STZ-injected groups, which were reversed by OPC-31260 (a V2R antagonist) and overcome by NaF (a G protein activator). The splenorenal shunt V2R mRNA expression was increased while Gα proteins mRNA expressions were decreased in BDL/STZ rats compared to BDL rats. The Gαq and Gα11 mRNA expressions also correlated with the maximal perfusion pressure changes to AVP. Diabetes diminished the portal-systemic collateral vascular response to AVP in rats with BDL-induced cirrhosis, probably via V2 receptor up-regulation and Gα proteins down-regulation.

Flight elements: Fault detection and fault management

NASA Technical Reports Server (NTRS)

Lum, H.; Patterson-Hine, A.; Edge, J. T.; Lawler, D.

1990-01-01

Fault management for an intelligent computational system must be developed using a top down integrated engineering approach. An approach proposed includes integrating the overall environment involving sensors and their associated data; design knowledge capture; operations; fault detection, identification, and reconfiguration; testability; causal models including digraph matrix analysis; and overall performance impacts on the hardware and software architecture. Implementation of the concept to achieve a real time intelligent fault detection and management system will be accomplished via the implementation of several objectives, which are: Development of fault tolerant/FDIR requirement and specification from a systems level which will carry through from conceptual design through implementation and mission operations; Implementation of monitoring, diagnosis, and reconfiguration at all system levels providing fault isolation and system integration; Optimize system operations to manage degraded system performance through system integration; and Lower development and operations costs through the implementation of an intelligent real time fault detection and fault management system and an information management system.

Effect of dopant on electrical properties of PVA doped NaF polymer electrolyte films

NASA Astrophysics Data System (ADS)

Irfan, Mohammed; Razikha Banu, S.; Manjunath, A.; Mahesh, S. S.

2018-05-01

Polymer electrolyte films of Poly (vinyl alcohol) (PVA) doped with Sodium fluoride (NaF) of different weight ratios (6, 8 and 10 wt %) were prepared by solution casting method. We observed that AC conductivity was found to increase with rise in temperature and frequency with slope S ranging from 0.7 to 0.9. The Correlated Barrier Hopping (CBH) model is used because the value of S is temperature dependent and its value decreases by increasing temperature. The dielectric constant has high values in the low frequency region; this is due to the existence of various types of polarization mechanisms. The X-ray diffraction (XRD) diagram of pure PVA shows a characteristic peak at 2θ=19.490 indicating its semi-crystalline nature. On the incorporation of NaF salt into the polymer, the intensity of peak decreases gradually, suggesting a decrease in the degree of crystallinity of the complex. The CBH model is used to calculate the polaron binding energy (WM), the Hoping distance (R), the minimum hoping distance (Rmin) and the activation energy (Ea) results are discussed.

A new perspective on metals and other contaminants in fluoridation chemicals*

PubMed Central

Mullenix, Phyllis J

2014-01-01

Background: Fluoride additives contain metal contaminants that must be diluted to meet drinking water regulations. However, each raw additive batch supplied to water facilities does not come labeled with concentrations per contaminant. This omission distorts exposure profiles and the risks associated with accidents and routine use. Objectives: This study provides an independent determination of the metal content of raw fluoride products. Methods: Metal concentrations were analyzed in three hydrofluorosilicic acid (HFS) and four sodium fluoride (NaF) samples using inductively coupled plasma-atomic emission spectrometry. Arsenic levels were confirmed using graphite furnace atomic absorption analysis. Results: Results show that metal content varies with batch, and all HFS samples contained arsenic (4.9–56.0 ppm) or arsenic in addition to lead (10.3 ppm). Two NaF samples contained barium (13.3–18.0 ppm) instead. All HFS (212–415 ppm) and NaF (3312–3630 ppm) additives contained a surprising amount of aluminum. Conclusions: Such contaminant content creates a regulatory blind spot that jeopardizes any safe use of fluoride additives. PMID:24999851

NO-FAULT COMPENSATION FOR MEDICAL INJURIES: TRENDS AND CHALLENGES.

PubMed

Kassim, Puteri Nemie

2014-12-01

As an alternative to the tort or fault-based system, a no-fault compensation system has been viewed as having the potential to overcome problems inherent in the tort system by providing fair, speedy and adequate compensation for medically injured victims. Proponents of the suggested no-fault compensation system have argued that this system is more efficient in terms of time and money, as well as in making the circumstances in which compensation is paid, much clearer. However, the arguments against no-fault compensation systems are mainly on issues of funding difficulties, accountability and deterrence, particularly, once fault is taken out of the equation. Nonetheless, the no-fault compensation system has been successfully implemented in various countries but, at the same time, rejected in some others, as not being implementable. In the present trend, the no-fault system seems to fit the needs of society by offering greater access to justice for medically injured victims and providing a clearer "road map" towards obtaining suitable redress. This paper aims at providing the readers with an overview of the characteristics of the no fault compensation system and some examples of countries that have implemented it. Qualitative Research-Content Analysis. Given the many problems and hurdles posed by the tort or fault-based system, it is questionable that it can efficiently play its role as a mechanism that affords fair and adequate compensation for victims of medical injuries. However, while a comprehensive no-fault compensation system offers a tempting alternative to the tort or fault-based system, to import such a change into our local scenario requires a great deal of consideration. There are major differences, mainly in terms of social standing, size of population, political ideology and financial commitment, between Malaysia and countries that have successfully implemented no-fault systems. Nevertheless, implementing a no-fault compensation system in Malaysia is not entirely impossible. A custom-made no-fault model tailored to suit our local scenario can be promising, provided that a thorough research is made, assessing the viability of a no-fault system in Malaysia, addressing the inherent problems and, consequently, designing a workable no-fault system in Malaysia.

High-Intensity Radiated Field Fault-Injection Experiment for a Fault-Tolerant Distributed Communication System

NASA Technical Reports Server (NTRS)

Yates, Amy M.; Torres-Pomales, Wilfredo; Malekpour, Mahyar R.; Gonzalez, Oscar R.; Gray, W. Steven

2010-01-01

Safety-critical distributed flight control systems require robustness in the presence of faults. In general, these systems consist of a number of input/output (I/O) and computation nodes interacting through a fault-tolerant data communication system. The communication system transfers sensor data and control commands and can handle most faults under typical operating conditions. However, the performance of the closed-loop system can be adversely affected as a result of operating in harsh environments. In particular, High-Intensity Radiated Field (HIRF) environments have the potential to cause random fault manifestations in individual avionic components and to generate simultaneous system-wide communication faults that overwhelm existing fault management mechanisms. This paper presents the design of an experiment conducted at the NASA Langley Research Center's HIRF Laboratory to statistically characterize the faults that a HIRF environment can trigger on a single node of a distributed flight control system.

The fractional laser-induced coagulation zone characterized over time by laser scanning confocal microscopy-A proof of concept study.

PubMed

Banzhaf, Christina A; Lin, Lynlee L; Dang, Nhung; Freeman, Michael; Haedersdal, Merete; Prow, Tarl W

2018-01-01

Ablative fractional laser (AFXL) is an acknowledged technique to increase uptake of topical agents in skin. Micro thermal ablation zones (MAZs) consist of ablated vertical channels surrounded by a coagulation zone (CZ). Laser scanning confocal microscopy (LSCM) images individual MAZs at 733 nm (reflectance confocal microscopy (RCM)). Further, LSCM can image sodium fluorescein (NaF) fluorescence with 488 nm excitation (fluorescence confocal microcopy (FCM)), a small hydrophilic test molecule (370 MW, log P -1.52), which may simulate uptake, bio-distribution and kinetics of small hydrophilic drugs. To explore LSCM for combined investigations of CZ thickness and uptake, bio-distribution and kinetics of NaF in AFXL-exposed skin. Excised human abdominal skin samples were exposed to AFXL (15 mJ/microbeam, 2% density) and NaF gel (1000 μg/ml, 10 μl/cm2) in six repetitions, including untreated control samples. CZ thickness and spatiotemporal fluorescence intensities (FI) were quantified up to four hours after NaF application by RCM and FCM. Test sites were scanned to a depth of 200 μm, quantifying thickness of skin compartments (stratum corneum, epidermis, upper dermis), individual CZ thicknesses and FI in CZ and surrounding skin. RCM images established skin morphology to a depth of 200 μm. The CZ thickness measurements were feasible to a depth of 50 μm, and remained unchanged over time at 50 μm (P > 0.5). FI were detected to a depth of 160 μm and remained constant in CZ up to four hours after NaF application (15 minutes: 79 AU (73-92 AU), 60 minutes: 72 AU (58-82 AU), four hours: 78 AU (71-90 AU), P > 0.1). In surrounding skin, FI increased significantly over time, but remained lower than FI in CZ (15 minutes: 21 AU (17-22 AU), 60 minutes: 21 AU (19-26 AU), four hours: 42 (31- 48 AU), P = 0.03). AFXL-processed skin generated higher FI compared to non-laser processed skin in epidermis and upper dermis at 60 minutes and four hours (P = 0.03). By LSCM, assessment of the AFXL-induced CZ thickness was feasible to a depth of 50 μm, and assessment of FI from a small hydrophilic test molecule, NaF in CZ and surrounding skin feasible to a depth of 160 μm. Lasers Surg. Med. 50:70-77, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Fault recovery characteristics of the fault tolerant multi-processor

NASA Technical Reports Server (NTRS)

Padilla, Peter A.

1990-01-01

The fault handling performance of the fault tolerant multiprocessor (FTMP) was investigated. Fault handling errors detected during fault injection experiments were characterized. In these fault injection experiments, the FTMP disabled a working unit instead of the faulted unit once every 500 faults, on the average. System design weaknesses allow active faults to exercise a part of the fault management software that handles byzantine or lying faults. It is pointed out that these weak areas in the FTMP's design increase the probability that, for any hardware fault, a good LRU (line replaceable unit) is mistakenly disabled by the fault management software. It is concluded that fault injection can help detect and analyze the behavior of a system in the ultra-reliable regime. Although fault injection testing cannot be exhaustive, it has been demonstrated that it provides a unique capability to unmask problems and to characterize the behavior of a fault-tolerant system.

Coordinated Fault-Tolerance for High-Performance Computing Final Project Report

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

Panda, Dhabaleswar Kumar; Beckman, Pete

2011-07-28

With the Coordinated Infrastructure for Fault Tolerance Systems (CIFTS, as the original project came to be called) project, our aim has been to understand and tackle the following broad research questions, the answers to which will help the HEC community analyze and shape the direction of research in the field of fault tolerance and resiliency on future high-end leadership systems. Will availability of global fault information, obtained by fault information exchange between the different HEC software on a system, allow individual system software to better detect, diagnose, and adaptively respond to faults? If fault-awareness is raised throughout the system throughmore » fault information exchange, is it possible to get all system software working together to provide a more comprehensive end-to-end fault management on the system? What are the missing fault-tolerance features that widely used HEC system software lacks today that would inhibit such software from taking advantage of systemwide global fault information? What are the practical limitations of a systemwide approach for end-to-end fault management based on fault awareness and coordination? What mechanisms, tools, and technologies are needed to bring about fault awareness and coordination of responses on a leadership-class system? What standards, outreach, and community interaction are needed for adoption of the concept of fault awareness and coordination for fault management on future systems? Keeping our overall objectives in mind, the CIFTS team has taken a parallel fourfold approach. Our central goal was to design and implement a light-weight, scalable infrastructure with a simple, standardized interface to allow communication of fault-related information through the system and facilitate coordinated responses. This work led to the development of the Fault Tolerance Backplane (FTB) publish-subscribe API specification, together with a reference implementation and several experimental implementations on top of existing publish-subscribe tools. We enhanced the intrinsic fault tolerance capabilities representative implementations of a variety of key HPC software subsystems and integrated them with the FTB. Targeting software subsystems included: MPI communication libraries, checkpoint/restart libraries, resource managers and job schedulers, and system monitoring tools. Leveraging the aforementioned infrastructure, as well as developing and utilizing additional tools, we have examined issues associated with expanded, end-to-end fault response from both system and application viewpoints. From the standpoint of system operations, we have investigated log and root cause analysis, anomaly detection and fault prediction, and generalized notification mechanisms. Our applications work has included libraries for fault-tolerance linear algebra, application frameworks for coupled multiphysics applications, and external frameworks to support the monitoring and response for general applications. Our final goal was to engage the high-end computing community to increase awareness of tools and issues around coordinated end-to-end fault management.« less

A fault isolation method based on the incidence matrix of an augmented system

NASA Astrophysics Data System (ADS)

Chen, Changxiong; Chen, Liping; Ding, Jianwan; Wu, Yizhong

2018-03-01

A new approach is proposed for isolating faults and fast identifying the redundant sensors of a system in this paper. By introducing fault signal as additional state variable, an augmented system model is constructed by the original system model, fault signals and sensor measurement equations. The structural properties of an augmented system model are provided in this paper. From the viewpoint of evaluating fault variables, the calculating correlations of the fault variables in the system can be found, which imply the fault isolation properties of the system. Compared with previous isolation approaches, the highlights of the new approach are that it can quickly find the faults which can be isolated using exclusive residuals, at the same time, and can identify the redundant sensors in the system, which are useful for the design of diagnosis system. The simulation of a four-tank system is reported to validate the proposed method.

The Effect of a Low Fluoride Delivery System on Bacterial Metabolism.

DTIC Science & Technology

1980-09-01

Fluorides, an4 -Ique mechanisms, slow release delivery, temporary restora- tions, bacterial attachment, Streptococcus mutans , bacterial metabo’ilsm...concentrations of NaF, SnF 4 , Na2SnF6 , TiF 4 , and SnCI2 on altering plaque formation by Streptococcus mutans NCTC 10449. Specific tests were...preparation. Microorganisms, Growth Media, and Growth A streptomycin resistant mutant of Streptococcus mutans NCTC 10449 (Bratthall serotype c) has been

Parameter Transient Behavior Analysis on Fault Tolerant Control System

NASA Technical Reports Server (NTRS)

Belcastro, Christine (Technical Monitor); Shin, Jong-Yeob

2003-01-01

In a fault tolerant control (FTC) system, a parameter varying FTC law is reconfigured based on fault parameters estimated by fault detection and isolation (FDI) modules. FDI modules require some time to detect fault occurrences in aero-vehicle dynamics. This paper illustrates analysis of a FTC system based on estimated fault parameter transient behavior which may include false fault detections during a short time interval. Using Lyapunov function analysis, the upper bound of an induced-L2 norm of the FTC system performance is calculated as a function of a fault detection time and the exponential decay rate of the Lyapunov function.

Development of an accurate transmission line fault locator using the global positioning system satellites

NASA Technical Reports Server (NTRS)

Lee, Harry

1994-01-01

A highly accurate transmission line fault locator based on the traveling-wave principle was developed and successfully operated within B.C. Hydro. A transmission line fault produces a fast-risetime traveling wave at the fault point which propagates along the transmission line. This fault locator system consists of traveling wave detectors located at key substations which detect and time tag the leading edge of the fault-generated traveling wave as if passes through. A master station gathers the time-tagged information from the remote detectors and determines the location of the fault. Precise time is a key element to the success of this system. This fault locator system derives its timing from the Global Positioning System (GPS) satellites. System tests confirmed the accuracy of locating faults to within the design objective of +/-300 meters.

A footwall system of faults associated with a foreland thrust in Montana

NASA Astrophysics Data System (ADS)

Watkinson, A. J.

1993-05-01

Some recent structural geology models of faulting have promoted the idea of a rigid footwall behaviour or response under the main thrust fault, especially for fault ramps or fault-bend folds. However, a very well-exposed thrust fault in the Montana fold and thrust belt shows an intricate but well-ordered system of subsidiary minor faults in the footwall position with respect to the main thrust fault plane. Considerable shortening has occurred off the main fault in this footwall collapse zone and the distribution and style of the minor faults accord well with published patterns of aftershock foci associated with thrust faults. In detail, there appear to be geometrically self-similar fault systems from metre length down to a few centimetres. The smallest sets show both slip and dilation. The slickensides show essentially two-dimensional displacements, and three slip systems were operative—one parallel to the bedding, and two conjugate and symmetric about the bedding (acute angle of 45-50°). A reconstruction using physical analogue models suggests one possible model for the evolution and sequencing of slip of the thrust fault system.

Integrated Approach To Design And Analysis Of Systems

NASA Technical Reports Server (NTRS)

Patterson-Hine, F. A.; Iverson, David L.

1993-01-01

Object-oriented fault-tree representation unifies evaluation of reliability and diagnosis of faults. Programming/fault tree described more fully in "Object-Oriented Algorithm For Evaluation Of Fault Trees" (ARC-12731). Augmented fault tree object contains more information than fault tree object used in quantitative analysis of reliability. Additional information needed to diagnose faults in system represented by fault tree.

Fault recovery for real-time, multi-tasking computer system

NASA Technical Reports Server (NTRS)

Hess, Richard (Inventor); Kelly, Gerald B. (Inventor); Rogers, Randy (Inventor); Stange, Kent A. (Inventor)

2011-01-01

System and methods for providing a recoverable real time multi-tasking computer system are disclosed. In one embodiment, a system comprises a real time computing environment, wherein the real time computing environment is adapted to execute one or more applications and wherein each application is time and space partitioned. The system further comprises a fault detection system adapted to detect one or more faults affecting the real time computing environment and a fault recovery system, wherein upon the detection of a fault the fault recovery system is adapted to restore a backup set of state variables.

First-Principles Analysis of Defect Thermodynamics and Ion Transport in Inorganic SEI Compounds: LiF and NaF

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

Yildirim, Handan; Kinaci, Alper; Chan, Maria K. Y.

The formation mechanism and composition of the solid electrolyte interphase (SEI) in lithium ion batteries has been widely explored. However, relatively little is known about the function of the SEI as a transport medium. Such critical information is directly relevant to battery rate performance, power loss, and capacity fading. To partially bridge this gap in the case of inorganic SEI compounds, we report herein the results of first-principles calculations on the defect thermodynamics, the dominant diffusion carriers, and the diffusion pathways associated with crystalline LiF and NaF, which are stable components of the SEI in Li-ion and Na-ion batteries, respectively.more » The thermodynamics of common point defects are computed, and the dominant diffusion carriers are determined over a voltage range of 0-4 V, corresponding to conditions relevant to both anode and cathode SEI's. Our analyses reveal that for both compounds, vacancy defects are energetically more favorable, therefore form more readily than interstitials, due to the close-packed nature of the crystal structures. However, the vacancy concentrations are very small for the diffusion processes facilitated by defects. Ionic conductivities are calculated as a function of voltage, considering the diffusion carrier concentration and the diffusion barriers as determined by nudged elastic band calculations. These conductivities are more than ten orders of magnitude smaller in NaF than in LiF. As compared to the diffusivity of Li in other common inorganic SEI compounds, such as Li2CO3 and Li2O,the cation diffusivity in LiF and NaF is quite low, with at least three orders of magnitude lower ionic conductivities. The results quantify the extent to which fluorides pose rate limitations in Li and Na batteries.« less

Aluminium, carbonyls and cytokines in human nipple aspirate fluids: Possible relationship between inflammation, oxidative stress and breast cancer microenvironment.

PubMed

Mannello, F; Ligi, D; Canale, M

2013-11-01

The human breast is likely exposed to Al (aluminium) from many sources including diet and personal care products. Underarm applications of aluminium salt-based antiperspirant provide a possible long-term source of exposure, especially after underarm applications to shaved and abraded skin. Al research in breast fluids likely reflects the intraductal microenvironment. We found increased levels of aluminium in noninvasively collected nipple aspirate fluids (NAF) from 19 breast cancer patients compared with 16 healthy control subjects (268 vs 131 μg/l, respectively; p < 0.0001). In the same NAF samples we found significantly increased levels of protein oxidative carbonyls in cancer patients compared to healthy women (2.35 vs 0.41 nmol/mg prot, respectively; p < 0.0001). Aluminium content and carbonyl levels showed a significant positive linear correlation (r(2) 0.6628, p < 0.0001). In cancer NAF samples (containing higher amounts of aluminium salts) we also found a significantly increased levels of pro-inflammatory cytokines (IL-1β, IL-6, IL-12 p70, and TNF-α) and chemoattractant CC and CXC chemokines (IL-8, MIP-1α and MCP-1). In 12 invasive cancer NAF samples we found a significant positive linear correlation among aluminium, carbonyls and pro-inflammatory IL-6 cytokine (Y = 64.79x-39.63, r(2) 0.8192, p < 0.0005), as well as pro-inflammatory monocyte chemoattractant MCP-1 cytokine (Y = 2026x-866, r(2) 0.9495, p < 0.0001). In addition to emerging evidence, our results support the possible involvement of aluminium ions in oxidative and inflammatory status perturbations of breast cancer microenvironment, suggesting aluminium accumulation in breast microenvironment as a possible risk factor for oxidative/inflammatory phenotype of breast cells. © 2013.

Casein phosphopeptide-amorphous calcium phosphate remineralization of primary teeth early enamel lesions.

PubMed

Zhou, Chunhua; Zhang, Dongliang; Bai, Yuxing; Li, Song

2014-01-01

Early childhood caries (ECC) is a serious problem that progresses rapidly and often goes untreated. Current traumatic treatments may be replaced by safe and effective remineralization at very early stages. The aim of this in vitro study was to evaluate the remineralization effects of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste on enamel lesions by assessing ultrastructure, nanomechanical properties, and compound and elemental analysis. Enamel specimens from 6-year-old children were divided into groups: (1) native enamel; (2) water as negative control; (3) 500ppm NaF as positive control; and (4-7) CPP-ACP paste for 4, 8, 12, and 24h, as test groups. Ultrastructure and roughness were observed by atomic force microscopy (AFM); nanohardness and elastic modulus were measured by nanoindentation; compound and crystal size of enamel surface patterns were investigated by X-ray diffractometer (XRD). An electron microprobe (EPMA) was used for element analysis. Data were analyzed using one-way ANOVA. The CPP-ACP paste repaired the microstructure of enamel, including prism and interprism, through significantly increased hydroxyapatite crystal size (12.06±0.21nm) and Ca/P molar ratios (1.637±0.096) as compared with NaF (8.56±0.13nm crystal size and 1.397±0.086 Ca/P, p<0.01). Both CPP-ACP and NaF decrease roughness, and increase the nanohardness and elastic modulus, with no significant differences between the materials. The CPP-ACP paste is more suitable for children than NaF, due to advantages for remineralization. The AFM, nanoindentation, EPMA, and XRD are very helpful methods for further understanding of microscale and nanoscale remineralization mechanisms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Five ab initio potential energy and dipole moment surfaces for hydrated NaCl and NaF. I. Two-body interactions

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

Wang, Yimin, E-mail: yimin.wang@emory.edu; Bowman, Joel M., E-mail: jmbowma@emory.edu; Kamarchik, Eugene, E-mail: eugene.kamarchik@gmail.com

2016-03-21

We report full-dimensional, ab initio-based potentials and dipole moment surfaces for NaCl, NaF, Na{sup +}H{sub 2}O, F{sup −}H{sub 2}O, and Cl{sup −}H{sub 2}O. The NaCl and NaF potentials are diabatic ones that dissociate to ions. These are obtained using spline fits to CCSD(T)/aug-cc-pV5Z energies. In addition, non-linear least square fits using the Born-Mayer-Huggins potential are presented, providing accurate parameters based strictly on the current ab initio energies. The long-range behavior of the NaCl and NaF potentials is shown to go, as expected, accurately to the point-charge Coulomb interaction. The three ion-H{sub 2}O potentials are permutationally invariant fits to roughly 20 000more » coupled cluster CCSD(T) energies (awCVTZ basis for Na{sup +} and aVTZ basis for Cl{sup −} and F{sup −}), over a large range of distances and H{sub 2}O intramolecular configurations. These potentials are switched accurately in the long range to the analytical ion-dipole interactions, to improve computational efficiency. Dipole moment surfaces are fits to MP2 data; for the ion-ion cases, these are well described in the intermediate- and long-range by the simple point-charge expression. The performance of these new fits is examined by direct comparison to additional ab initio energies and dipole moments along various cuts. Equilibrium structures, harmonic frequencies, and electronic dissociation energies are also reported and compared to direct ab initio results. These indicate the high fidelity of the new PESs.« less

Evaluation of corrosion resistance and surface characteristics of orthodontic wires immersed in different mouthwashes.

PubMed

Nalbantgil, Didem; Ulkur, Feyza; Kardas, Gulfeza; Culha, Mustafa

2016-11-25

Patients use mouthwashes in addition to mechanical cleaning during orthodontic treatment. The effects of mouthwashes on the archwires have not been examined yet. To compare the corrosion resistance of four different arch wires and corrosion effects of different mouthwashes to formulate a biocompatible and mechanically useful arch wire and mouthwash combination. Each group comprised of 4 wire samples of 2 cm 0.016 × 0.022 inch. 1st group: ion implanted nickel titanium (INT), 2nd group: nickel titanium, without ion implantation (NT), 3rd group: micro layered esthetic nickel titanium (ENT), 4th group: stainless steel (SS) wires. They were immersed inside 2 ml of artificial saliva solutions (AS) for the control, or AS (9%) combined with 1 of the 3 mouthwashes (91%) for study groups, for 24 hours. These mouthwashes were essential oil (EO), chlorhexidine (CHX), sodium-fluoride (NaF). An electrochemical analyzer was used for electrochemical impedance spectroscopy measurements. High corrosion resistance was obtained for ENT than the other wires. The corrosion potentials are 0.007, -0.042, 0.074 and -0.015 V (Ag/AgCl) for ENT, INT, SS and NT in the artificial salivary, respectively. In NaF containing mouthwash Rp value of ENT is significantly high in comparison to others. The impedance responses of all materials increased significantly in the presence of NaF mouthwash as well as in the CHX mouthwash. Low frequencies are seen at all materials in EO mouthwash. Diameters of loops are 22, 5.9, 5.9 and 3.7 MΩ at ENT, INT, SS and NT. In this study, micro layered esthetic nickel titanium wires are found biocompatible among other wires and NaF and CHX mouthwashes can be recommend for their good corrosion resistance during fixed orthodontic therapy.

Effect of xylitol varnishes on remineralization of artificial enamel caries lesions in vitro.

PubMed

Cardoso, C A B; de Castilho, A R F; Salomão, P M A; Costa, E N; Magalhães, A C; Buzalaf, M A R

2014-11-01

Analyse the effect of varnishes containing xylitol alone or combined with fluoride on the remineralization of artificial enamel caries lesions in vitro. Bovine enamel specimens were randomly allocated to 7 groups (n=15/group). Artificial caries lesions were produced by immersion in 30 mL of lactic acid buffer containing 3mM CaCl2·2H2O, 3mM KH2PO4, 6 μM tetraetil metil diphosphanate (pH 5.0) for 6 days. The enamel blocks were treated with the following varnishes: 10% xylitol; 20% xylitol; 10% xylitol plus F (5% NaF); 20% xylitol plus F (5% NaF); Duofluorid™ (6% NaF, 2.71% F+6% CaF2), Duraphat™ (5% NaF, positive control) and placebo (no-F/xylitol, negative control). The varnishes were applied in a thin layer and removed after 6h. The blocks were subjected to pH-cycles (demineralization-2h/remineralization-22 h during 8 days) and enamel alterations were quantified by surface hardness and transversal microradiography. The percentage of surface hardness recovery (%SHR), the integrated mineral loss and lesion depth were statistically analysed by ANOVA/Tukey's test or Kruskal-Wallis/Dunn's test (p<0.05). Enamel surface remineralization was significantly increased by Duraphat™, 10% xylitol plus F and 20% xylitol plus F formulations, while significant subsurface mineral remineralization could be seen only for enamel treated with Duraphat™, Duofluorid™ and 20% xylitol formulations. 20% xylitol varnishes seem to be promising alternatives to increase remineralization of artificial caries lesions. effective vehicles are desirable for caries control. Xylitol varnishes seem to be promising alternatives to increase enamel remineralization in vitro, which should be confirmed by in situ and clinical studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effect of increasing sodium fluoride concentrations on erosion and attrition of enamel and dentine in vitro.

PubMed

Austin, R S; Rodriguez, J M; Dunne, S; Moazzez, R; Bartlett, D W

2010-10-01

To investigate the effect of an aqueous sodium fluoride solution of increasing concentration on erosion and attrition of enamel and dentine in vitro. Enamel and dentine sections from caries-free human third molars were polished flat and taped (exposing a 3 mm x 3 mm area) before being randomly allocated to 1 of 5 groups per substrate (n=10/gp): G1 (distilled water control); G2 (225 ppm NaF); G3 (1450 ppm NaF); G4 (5000 ppm NaF); G5 (19,000 ppm NaF). All specimens were subjected to 5, 10 and 15 cycles of experimental wear [1 cycle=artificial saliva (2h, pH 7.0)+erosion (0.3% citric acid, pH 3.2, 5 min)+fluoride/control (5 min)+attrition (60 linear strokes in artificial saliva from enamel antagonists loaded to 300 g)]. Following tape removal, step height (SH) in mum was measured using optical profilometry. When the number of cycles increased the amount of tooth surface loss increased significantly in enamel and dentine after attrition and erosion and for dentine after attrition. Attrition and erosion resulted in greater surface loss than attrition alone after 15 cycles of experimental wear of enamel. 5000 ppm and 19,000 ppm sodium fluoride solutions had a protective effect on erosive and attritional enamel tooth wear in vitro, however no other groups showed significant differences. The more intensive the fluoride regime the more protection was afforded to enamel from attrition and erosion. However, in this study no such protective effect was demonstrated for dentine. Copyright 2010 Elsevier Ltd. All rights reserved.

Correlation between uncoupled ATP hydrolysis and heat production by the sarcoplasmic reticulum Ca2+-ATPase: coupling effect of fluoride.

PubMed

Reis, M; Farage, M; de Souza, A C; de Meis, L

2001-11-16

The sarcoplasmic reticulum Ca(2+)-ATPase transports Ca(2+) using the chemical energy derived from ATP hydrolysis. Part of the chemical energy is used to translocate Ca(2+) through the membrane (work) and part is dissipated as heat. The amount of heat produced during catalysis increases after formation of the Ca(2+) gradient across the vesicle membrane. In the absence of gradient (leaky vesicles) the amount of heat produced/mol of ATP cleaved is half of that measured in the presence of the gradient. After formation of the gradient, part of the ATPase activity is not coupled to Ca(2+) transport. We now show that NaF can impair the uncoupled ATPase activity with discrete effect on the ATPase activity coupled to Ca(2+) transport. For the control vesicles not treated with NaF, after formation of the gradient only 20% of the ATP cleaved is coupled to Ca(2+) transport, and the caloric yield of the total ATPase activity (coupled plus uncoupled) is 22.8 kcal released/mol of ATP cleaved. In contrast, the vesicles treated with NaF consume only the ATP needed to maintain the gradient, and the caloric yield of ATP hydrolysis is 3.1 kcal/mol of ATP. The slow ATPase activity measured in vesicles treated with NaF has the same Ca(2+) dependence as the control vesicles. This demonstrates unambiguously that the uncoupled activity is an actual pathway of the Ca(2+)-ATPase rather than a contaminating phosphatase. We conclude that when ATP hydrolysis occurs without coupled biological work most of the chemical energy is dissipated as heat. Thus, uncoupled ATPase activity appears to be the mechanistic feature underlying the ability of the Ca(2+)-ATPase to modulated heat production.

Stafford fault system: 120 million year fault movement history of northern Virginia

USGS Publications Warehouse

Powars, David S.; Catchings, Rufus D.; Horton, J. Wright; Schindler, J. Stephen; Pavich, Milan J.

2015-01-01

The Stafford fault system, located in the mid-Atlantic coastal plain of the eastern United States, provides the most complete record of fault movement during the past ~120 m.y. across the Virginia, Washington, District of Columbia (D.C.), and Maryland region, including displacement of Pleistocene terrace gravels. The Stafford fault system is close to and aligned with the Piedmont Spotsylvania and Long Branch fault zones. The dominant southwest-northeast trend of strong shaking from the 23 August 2011, moment magnitude Mw 5.8 Mineral, Virginia, earthquake is consistent with the connectivity of these faults, as seismic energy appears to have traveled along the documented and proposed extensions of the Stafford fault system into the Washington, D.C., area. Some other faults documented in the nearby coastal plain are clearly rooted in crystalline basement faults, especially along terrane boundaries. These coastal plain faults are commonly assumed to have undergone relatively uniform movement through time, with average slip rates from 0.3 to 1.5 m/m.y. However, there were higher rates during the Paleocene–early Eocene and the Pliocene (4.4–27.4 m/m.y), suggesting that slip occurred primarily during large earthquakes. Further investigation of the Stafford fault system is needed to understand potential earthquake hazards for the Virginia, Maryland, and Washington, D.C., area. The combined Stafford fault system and aligned Piedmont faults are ~180 km long, so if the combined fault system ruptured in a single event, it would result in a significantly larger magnitude earthquake than the Mineral earthquake. Many structures most strongly affected during the Mineral earthquake are along or near the Stafford fault system and its proposed northeastward extension.

Differential Extension, Displacement Transfer, and the South to North Decrease in Displacement on the Furnace Creek - Fish Lake Valley Fault System, Western Great Basin.

NASA Astrophysics Data System (ADS)

Katopody, D. T.; Oldow, J. S.

2015-12-01

The northwest-striking Furnace Creek - Fish Lake Valley (FC-FLV) fault system stretches for >250 km from southeastern California to western Nevada, forms the eastern boundary of the northern segment of the Eastern California Shear Zone, and has contemporary displacement. The FC-FLV fault system initiated in the mid-Miocene (10-12 Ma) and shows a south to north decrease in displacement from a maximum of 75-100 km to less than 10 km. Coeval elongation by extension on north-northeast striking faults within the adjoining blocks to the FC-FLV fault both supply and remove cumulative displacement measured at the northern end of the transcurrent fault system. Elongation and displacement transfer in the eastern block, constituting the southern Walker Lane of western Nevada, exceeds that of the western block and results in the net south to north decrease in displacement on the FC-FLV fault system. Elongation in the eastern block is accommodated by late Miocene to Pliocene detachment faulting followed by extension on superposed, east-northeast striking, high-angle structures. Displacement transfer from the FC-FLV fault system to the northwest-trending faults of the central Walker Lane to the north is accomplished by motion on a series of west-northwest striking transcurrent faults, named the Oriental Wash, Sylvania Mountain, and Palmetto Mountain fault systems. The west-northwest striking transcurrent faults cross-cut earlier detachment structures and are kinematically linked to east-northeast high-angle extensional faults. The transcurrent faults are mapped along strike for 60 km to the east, where they merge with north-northwest faults forming the eastern boundary of the southern Walker Lane. The west-northwest trending transcurrent faults have 30-35 km of cumulative left-lateral displacement and are a major contributor to the decrease in right-lateral displacement on the FC-FLV fault system.

Multiple incipient sensor faults diagnosis with application to high-speed railway traction devices.

PubMed

Wu, Yunkai; Jiang, Bin; Lu, Ningyun; Yang, Hao; Zhou, Yang

2017-03-01

This paper deals with the problem of incipient fault diagnosis for a class of Lipschitz nonlinear systems with sensor biases and explores further results of total measurable fault information residual (ToMFIR). Firstly, state and output transformations are introduced to transform the original system into two subsystems. The first subsystem is subject to system disturbances and free from sensor faults, while the second subsystem contains sensor faults but without any system disturbances. Sensor faults in the second subsystem are then formed as actuator faults by using a pseudo-actuator based approach. Since the effects of system disturbances on the residual are completely decoupled, multiple incipient sensor faults can be detected by constructing ToMFIR, and the fault detectability condition is then derived for discriminating the detectable incipient sensor faults. Further, a sliding-mode observers (SMOs) based fault isolation scheme is designed to guarantee accurate isolation of multiple sensor faults. Finally, simulation results conducted on a CRH2 high-speed railway traction device are given to demonstrate the effectiveness of the proposed approach. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Mechanical energy profiles of the combined ankle-foot system in normal gait: insights for prosthetic designs.

PubMed

Takahashi, Kota Z; Stanhope, Steven J

2013-09-01

Over the last half-century, the field of prosthetic engineering has continuously evolved with much attention being dedicated to restoring the mechanical energy properties of ankle joint musculatures during gait. However, the contributions of 'distal foot structures' (e.g., foot muscles, plantar soft tissue) have been overlooked. Therefore, the purpose of this study was to quantify the total mechanical energy profiles (e.g., power, work, and work-ratio) of the natural ankle-foot system (NAFS) by combining the contributions of the ankle joint and all distal foot structures during stance in level-ground steady state walking across various speeds (0.4, 0.6, 0.8 and 1.0 statures/s). The results from eleven healthy subjects walking barefoot indicated ankle joint and distal foot structures generally performed opposing roles: the ankle joint performed net positive work that systematically increased its energy generation with faster walking speeds, while the distal foot performed net negative work that systematically increased its energy absorption with faster walking speeds. Accounting for these simultaneous effects, the combined ankle-foot system exhibited increased work-ratios with faster walking. Most notably, the work-ratio was not significantly greater than 1.0 during the normal walking speed of 0.8 statures/s. Therefore, a prosthetic design that strategically exploits passive-dynamic properties (e.g., elastic energy storage and return) has the potential to replicate the mechanical energy profiles of the NAFS during level-ground steady-state walking. Copyright © 2013 Elsevier B.V. All rights reserved.

Strike-slip fault propagation and linkage via work optimization with application to the San Jacinto fault, California

NASA Astrophysics Data System (ADS)

Madden, E. H.; McBeck, J.; Cooke, M. L.

2013-12-01

Over multiple earthquake cycles, strike-slip faults link to form through-going structures, as demonstrated by the continuous nature of the mature San Andreas fault system in California relative to the younger and more segmented San Jacinto fault system nearby. Despite its immaturity, the San Jacinto system accommodates between one third and one half of the slip along the boundary between the North American and Pacific plates. It therefore poses a significant seismic threat to southern California. Better understanding of how the San Jacinto system has evolved over geologic time and of current interactions between faults within the system is critical to assessing this seismic hazard accurately. Numerical models are well suited to simulating kilometer-scale processes, but models of fault system development are challenged by the multiple physical mechanisms involved. For example, laboratory experiments on brittle materials show that faults propagate and eventually join (hard-linkage) by both opening-mode and shear failure. In addition, faults interact prior to linkage through stress transfer (soft-linkage). The new algorithm GROW (GRowth by Optimization of Work) accounts for this complex array of behaviors by taking a global approach to fault propagation while adhering to the principals of linear elastic fracture mechanics. This makes GROW a powerful tool for studying fault interactions and fault system development over geologic time. In GROW, faults evolve to minimize the work (or energy) expended during deformation, thereby maximizing the mechanical efficiency of the entire system. Furthermore, the incorporation of both static and dynamic friction allows GROW models to capture fault slip and fault propagation in single earthquakes as well as over consecutive earthquake cycles. GROW models with idealized faults reveal that the initial fault spacing and the applied stress orientation control fault linkage propensity and linkage patterns. These models allow the gains in efficiency provided by both hard-linkage and soft-linkage to be quantified and compared. Specialized models of interactions over the past 1 Ma between the Clark and Coyote Creek faults within the San Jacinto system reveal increasing mechanical efficiency as these fault structures change over time. Alongside this increasing efficiency is an increasing likelihood for single, larger earthquakes that rupture multiple fault segments. These models reinforce the sensitivity of mechanical efficiency to both fault structure and the regional tectonic stress orientation controlled by plate motions and provide insight into how slip may have been partitioned between the San Andreas and San Jacinto systems over the past 1 Ma.

ISHM-oriented adaptive fault diagnostics for avionics based on a distributed intelligent agent system

NASA Astrophysics Data System (ADS)

Xu, Jiuping; Zhong, Zhengqiang; Xu, Lei

2015-10-01

In this paper, an integrated system health management-oriented adaptive fault diagnostics and model for avionics is proposed. With avionics becoming increasingly complicated, precise and comprehensive avionics fault diagnostics has become an extremely complicated task. For the proposed fault diagnostic system, specific approaches, such as the artificial immune system, the intelligent agents system and the Dempster-Shafer evidence theory, are used to conduct deep fault avionics diagnostics. Through this proposed fault diagnostic system, efficient and accurate diagnostics can be achieved. A numerical example is conducted to apply the proposed hybrid diagnostics to a set of radar transmitters on an avionics system and to illustrate that the proposed system and model have the ability to achieve efficient and accurate fault diagnostics. By analyzing the diagnostic system's feasibility and pragmatics, the advantages of this system are demonstrated.

The continuation of the Kazerun fault system across the Sanandaj-Sirjan zone (Iran)

NASA Astrophysics Data System (ADS)

Safaei, Homayon

2009-08-01

The Kazerun (or Kazerun-Qatar) fault system is a north-trending dextral strike-slip fault zone in the Zagros mountain belt of Iran. It probably originated as a structure in the Panafrican basement. This fault system played an important role in the sedimentation and deformation of the Phanerozoic cover sequence and is still seismically active. No previous studies have reported the continuation of this important and ancient fault system northward across the Sanandaj-Sirjan zone. The Isfahan fault system is a north-trending dextral strike-slip fault across the Sanandaj-Sirjan zone that passes west of Isfahan city and is here recognized for the first time. This important fault system is about 220 km long and is seismically active in the basement as well as the sedimentary cover sequence. This fault system terminates to the south near the Main Zagros Thrust and to the north at the southern boundary of the Urumieh-Dokhtar zone. The Isfahan fault system is the boundary between the northern and southern parts of Sanandaj-Sirjan zone, which have fundamentally different stratigraphy, petrology, geomorphology, and geodynamic histories. Similarities in the orientations, kinematics, and geologic histories of the Isfahan and Kazerun faults and the way they affect the magnetic basement suggest that they are related. In fact, the Isfahan fault is a continuation of the Kazerun fault across the Sanandaj-Sirjan zone that has been offset by about 50 km of dextral strike-slip displacement along the Main Zagros Thrust.

Application Research of Fault Tree Analysis in Grid Communication System Corrective Maintenance

NASA Astrophysics Data System (ADS)

Wang, Jian; Yang, Zhenwei; Kang, Mei

2018-01-01

This paper attempts to apply the fault tree analysis method to the corrective maintenance field of grid communication system. Through the establishment of the fault tree model of typical system and the engineering experience, the fault tree analysis theory is used to analyze the fault tree model, which contains the field of structural function, probability importance and so on. The results show that the fault tree analysis can realize fast positioning and well repairing of the system. Meanwhile, it finds that the analysis method of fault tree has some guiding significance to the reliability researching and upgrading f the system.

Analysis of typical fault-tolerant architectures using HARP

NASA Technical Reports Server (NTRS)

Bavuso, Salvatore J.; Bechta Dugan, Joanne; Trivedi, Kishor S.; Rothmann, Elizabeth M.; Smith, W. Earl

1987-01-01

Difficulties encountered in the modeling of fault-tolerant systems are discussed. The Hybrid Automated Reliability Predictor (HARP) approach to modeling fault-tolerant systems is described. The HARP is written in FORTRAN, consists of nearly 30,000 lines of codes and comments, and is based on behavioral decomposition. Using the behavioral decomposition, the dependability model is divided into fault-occurrence/repair and fault/error-handling models; the characteristics and combining of these two models are examined. Examples in which the HARP is applied to the modeling of some typical fault-tolerant systems, including a local-area network, two fault-tolerant computer systems, and a flight control system, are presented.

Fault tolerant filtering and fault detection for quantum systems driven by fields in single photon states

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

Gao, Qing, E-mail: qing.gao.chance@gmail.com; Dong, Daoyi, E-mail: daoyidong@gmail.com; Petersen, Ian R., E-mail: i.r.petersen@gmai.com

The purpose of this paper is to solve the fault tolerant filtering and fault detection problem for a class of open quantum systems driven by a continuous-mode bosonic input field in single photon states when the systems are subject to stochastic faults. Optimal estimates of both the system observables and the fault process are simultaneously calculated and characterized by a set of coupled recursive quantum stochastic differential equations.

NASA ground terminal communication equipment automated fault isolation expert systems

NASA Technical Reports Server (NTRS)

Tang, Y. K.; Wetzel, C. R.

1990-01-01

The prototype expert systems are described that diagnose the Distribution and Switching System I and II (DSS1 and DSS2), Statistical Multiplexers (SM), and Multiplexer and Demultiplexer systems (MDM) at the NASA Ground Terminal (NGT). A system level fault isolation expert system monitors the activities of a selected data stream, verifies that the fault exists in the NGT and identifies the faulty equipment. Equipment level fault isolation expert systems are invoked to isolate the fault to a Line Replaceable Unit (LRU) level. Input and sometimes output data stream activities for the equipment are available. The system level fault isolation expert system compares the equipment input and output status for a data stream and performs loopback tests (if necessary) to isolate the faulty equipment. The equipment level fault isolation system utilizes the process of elimination and/or the maintenance personnel's fault isolation experience stored in its knowledge base. The DSS1, DSS2 and SM fault isolation systems, using the knowledge of the current equipment configuration and the equipment circuitry issues a set of test connections according to the predefined rules. The faulty component or board can be identified by the expert system by analyzing the test results. The MDM fault isolation system correlates the failure symptoms with the faulty component based on maintenance personnel experience. The faulty component can be determined by knowing the failure symptoms. The DSS1, DSS2, SM, and MDM equipment simulators are implemented in PASCAL. The DSS1 fault isolation expert system was converted to C language from VP-Expert and integrated into the NGT automation software for offline switch diagnoses. Potentially, the NGT fault isolation algorithms can be used for the DSS1, SM, amd MDM located at Goddard Space Flight Center (GSFC).

Expert System Detects Power-Distribution Faults

NASA Technical Reports Server (NTRS)

Walters, Jerry L.; Quinn, Todd M.

1994-01-01

Autonomous Power Expert (APEX) computer program is prototype expert-system program detecting faults in electrical-power-distribution system. Assists human operators in diagnosing faults and deciding what adjustments or repairs needed for immediate recovery from faults or for maintenance to correct initially nonthreatening conditions that could develop into faults. Written in Lisp.

Results of an electrical power system fault study (CDDF)

NASA Technical Reports Server (NTRS)

Dugal-Whitehead, N. R.; Johnson, Y. B.

1993-01-01

This report gives the results of an electrical power system fault study which has been conducted over the last 2 and one-half years. First, the results of the literature search into electrical power system faults in space and terrestrial power system applications are reported. A description of the intended implementations of the power system faults into the Large Autonomous Spacecraft Electrical Power System (LASEPS) breadboard is then presented. Then, the actual implementation of the faults into the breadboard is discussed along with a discussion describing the LASEPS breadboard. Finally, the results of the injected faults and breadboard failures are discussed.

Multiple Fault Isolation in Redundant Systems

NASA Technical Reports Server (NTRS)

Pattipati, Krishna R.; Patterson-Hine, Ann; Iverson, David

1997-01-01

Fault diagnosis in large-scale systems that are products of modern technology present formidable challenges to manufacturers and users. This is due to large number of failure sources in such systems and the need to quickly isolate and rectify failures with minimal down time. In addition, for fault-tolerant systems and systems with infrequent opportunity for maintenance (e.g., Hubble telescope, space station), the assumption of at most a single fault in the system is unrealistic. In this project, we have developed novel block and sequential diagnostic strategies to isolate multiple faults in the shortest possible time without making the unrealistic single fault assumption.

Multiple Fault Isolation in Redundant Systems

NASA Technical Reports Server (NTRS)

Pattipati, Krishna R.

1997-01-01

Fault diagnosis in large-scale systems that are products of modem technology present formidable challenges to manufacturers and users. This is due to large number of failure sources in such systems and the need to quickly isolate and rectify failures with minimal down time. In addition, for fault-tolerant systems and systems with infrequent opportunity for maintenance (e.g., Hubble telescope, space station), the assumption of at most a single fault in the system is unrealistic. In this project, we have developed novel block and sequential diagnostic strategies to isolate multiple faults in the shortest possible time without making the unrealistic single fault assumption.

Effects of sodium fluoride on blood cellular and humoral immunity in mice.

PubMed

Guo, Hongrui; Kuang, Ping; Luo, Qin; Cui, Hengmin; Deng, Huidan; Liu, Huan; Lu, Yujiao; Fang, Jing; Zuo, Zhicai; Deng, Junliang; Li, Yinglun; Wang, Xun; Zhao, Ling

2017-10-17

Exposure to high fluorine can cause toxicity in human and animals. Currently, there are no systematic studies on effects of high fluorine on blood cellular immunity and humoral immunity in mice. We evaluated the alterations of blood cellular immunity and humoral immunity in mice by using flow cytometry and ELISA. In the cellular immunity, we found that sodium fluoride (NaF) in excess of 12 mg/Kg resulted in a significant decrease in the percentages of CD3 + , CD3 + CD4 + , CD3 + CD8 + T lymphocytes in the peripheral blood. Meanwhile, serum T helper type 1 (Th1) cytokines including interleukin (IL)-2, interferon (IFN)-γ, tumor necrosis factor (TNF), and Th2 cytokines including IL-4, IL-6, IL-10, and Th17 cytokine (IL-17A) contents were decreased. In the humoral immunity, NaF reduced the peripheral blood percentages of CD19 + B lymphocytes and serum immunoglobulin A (IgA), immunoglobulin G (IgG) and immunoglobulin M (IgM). The above results show that NaF can reduce blood cellular and humoral immune function in mice, providing an excellent animal model for clinical studies on immunotoxicity-related fluorosis.

Fixed-Base Comb with Window-Non-Adjacent Form (NAF) Method for Scalar Multiplication

PubMed Central

Seo, Hwajeong; Kim, Hyunjin; Park, Taehwan; Lee, Yeoncheol; Liu, Zhe; Kim, Howon

2013-01-01

Elliptic curve cryptography (ECC) is one of the most promising public-key techniques in terms of short key size and various crypto protocols. For this reason, many studies on the implementation of ECC on resource-constrained devices within a practical execution time have been conducted. To this end, we must focus on scalar multiplication, which is the most expensive operation in ECC. A number of studies have proposed pre-computation and advanced scalar multiplication using a non-adjacent form (NAF) representation, and more sophisticated approaches have employed a width-w NAF representation and a modified pre-computation table. In this paper, we propose a new pre-computation method in which zero occurrences are much more frequent than in previous methods. This method can be applied to ordinary group scalar multiplication, but it requires large pre-computation table, so we combined the previous method with ours for practical purposes. This novel structure establishes a new feature that adjusts speed performance and table size finely, so we can customize the pre-computation table for our own purposes. Finally, we can establish a customized look-up table for embedded microprocessors. PMID:23881143

MO-AB-BRA-05: [18F]NaF PET/CT Imaging Biomarkers in Metastatic Prostate Cancer

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

Harmon, S; Perk, T; Lin, C

Purpose: Clinical use of {sup 18}F-Sodium Fluoride (NaF) PET/CT in metastatic settings often lacks technology to quantitatively measure full disease dynamics due to high tumor burden. This study assesses radiomics-based extraction of NaF PET/CT measures, including global metrics of overall burden and local metrics of disease heterogeneity, in metastatic prostate cancer for correlation to clinical outcomes. Methods: Fifty-six metastatic Castrate-Resistant Prostate Cancer (mCRPC) patients had NaF PET/CT scans performed at baseline and three cycles into chemotherapy (N=16) or androgen-receptor (AR) inhibitors (N=39). A novel technology, Quantitative Total Bone Imaging (QTBI), was used for analysis. Employing hybrid PET/CT segmentation and articulatedmore » skeletal-registration, QTBI allows for response assessment of individual lesions. Various SUV metrics were extracted from each lesion (iSUV). Global metrics were extracted from composite lesion-level statistics for each patient (pSUV). Proportion of detected lesions and those with significant response (%-increase or %-decrease) was calculated for each patient based on test-retest limits for iSUV metrics. Cox proportional hazard regression analyses were conducted between imaging metrics and progression-free survival (PFS). Results: Functional burden (pSUV{sub total}) assessed mid-treatment was the strongest univariate predictor of PFS (HR=2.03; p<0.0001). Various global metrics outperformed baseline clinical markers, including fraction of skeletal burden, mean uptake (pSUV{sub mean}), and heterogeneity of average lesion uptake (pSUV{sub hetero}). Of 43 patients with paired baseline/mid-treatment imaging, 40 showed heterogeneity in lesion-level response, containing populations of lesions with both increasing/decreasing metrics. Proportion of lesions with significantly increasing iSUV{sub mean} was highly predictive of clinical PFS (HR=2.0; p=0.0002). Patients exhibiting higher proportion of lesions with decreasing iSUV{sub total} saw prolonged radiographic PFS (HR=0.51; p=0.02). Conclusion: Technology presented here provides comprehensive disease quantification on NaF PET/CT imaging, showing strong correlation to clinical outcomes. Total functional burden as well as proportions of similarly responding lesions was predictive of PFS. This supports ongoing development of NaF PET/CT based imaging biomarkers in mCRPC. Prostate Cancer Foundation.« less

Simultaneous Sensor and Process Fault Diagnostics for Propellant Feed System

NASA Technical Reports Server (NTRS)

Cao, J.; Kwan, C.; Figueroa, F.; Xu, R.

2006-01-01

The main objective of this research is to extract fault features from sensor faults and process faults by using advanced fault detection and isolation (FDI) algorithms. A tank system that has some common characteristics to a NASA testbed at Stennis Space Center was used to verify our proposed algorithms. First, a generic tank system was modeled. Second, a mathematical model suitable for FDI has been derived for the tank system. Third, a new and general FDI procedure has been designed to distinguish process faults and sensor faults. Extensive simulations clearly demonstrated the advantages of the new design.

Fault-tolerant software - Experiment with the sift operating system. [Software Implemented Fault Tolerance computer

NASA Technical Reports Server (NTRS)

Brunelle, J. E.; Eckhardt, D. E., Jr.

1985-01-01

Results are presented of an experiment conducted in the NASA Avionics Integrated Research Laboratory (AIRLAB) to investigate the implementation of fault-tolerant software techniques on fault-tolerant computer architectures, in particular the Software Implemented Fault Tolerance (SIFT) computer. The N-version programming and recovery block techniques were implemented on a portion of the SIFT operating system. The results indicate that, to effectively implement fault-tolerant software design techniques, system requirements will be impacted and suggest that retrofitting fault-tolerant software on existing designs will be inefficient and may require system modification.

How fault evolution changes strain partitioning and fault slip rates in Southern California: Results from geodynamic modeling

NASA Astrophysics Data System (ADS)

Ye, Jiyang; Liu, Mian

2017-08-01

In Southern California, the Pacific-North America relative plate motion is accommodated by the complex southern San Andreas Fault system that includes many young faults (<2 Ma). The initiation of these young faults and their impact on strain partitioning and fault slip rates are important for understanding the evolution of this plate boundary zone and assessing earthquake hazard in Southern California. Using a three-dimensional viscoelastoplastic finite element model, we have investigated how this plate boundary fault system has evolved to accommodate the relative plate motion in Southern California. Our results show that when the plate boundary faults are not optimally configured to accommodate the relative plate motion, strain is localized in places where new faults would initiate to improve the mechanical efficiency of the fault system. In particular, the Eastern California Shear Zone, the San Jacinto Fault, the Elsinore Fault, and the offshore dextral faults all developed in places of highly localized strain. These younger faults compensate for the reduced fault slip on the San Andreas Fault proper because of the Big Bend, a major restraining bend. The evolution of the fault system changes the apportionment of fault slip rates over time, which may explain some of the slip rate discrepancy between geological and geodetic measurements in Southern California. For the present fault configuration, our model predicts localized strain in western Transverse Ranges and along the dextral faults across the Mojave Desert, where numerous damaging earthquakes occurred in recent years.

Advanced information processing system: Fault injection study and results

NASA Technical Reports Server (NTRS)

Burkhardt, Laura F.; Masotto, Thomas K.; Lala, Jaynarayan H.

1992-01-01

The objective of the AIPS program is to achieve a validated fault tolerant distributed computer system. The goals of the AIPS fault injection study were: (1) to present the fault injection study components addressing the AIPS validation objective; (2) to obtain feedback for fault removal from the design implementation; (3) to obtain statistical data regarding fault detection, isolation, and reconfiguration responses; and (4) to obtain data regarding the effects of faults on system performance. The parameters are described that must be varied to create a comprehensive set of fault injection tests, the subset of test cases selected, the test case measurements, and the test case execution. Both pin level hardware faults using a hardware fault injector and software injected memory mutations were used to test the system. An overview is provided of the hardware fault injector and the associated software used to carry out the experiments. Detailed specifications are given of fault and test results for the I/O Network and the AIPS Fault Tolerant Processor, respectively. The results are summarized and conclusions are given.

Sensor fault diagnosis of singular delayed LPV systems with inexact parameters: an uncertain system approach

NASA Astrophysics Data System (ADS)

Hassanabadi, Amir Hossein; Shafiee, Masoud; Puig, Vicenc

2018-01-01

In this paper, sensor fault diagnosis of a singular delayed linear parameter varying (LPV) system is considered. In the considered system, the model matrices are dependent on some parameters which are real-time measurable. The case of inexact parameter measurements is considered which is close to real situations. Fault diagnosis in this system is achieved via fault estimation. For this purpose, an augmented system is created by including sensor faults as additional system states. Then, an unknown input observer (UIO) is designed which estimates both the system states and the faults in the presence of measurement noise, disturbances and uncertainty induced by inexact measured parameters. Error dynamics and the original system constitute an uncertain system due to inconsistencies between real and measured values of the parameters. Then, the robust estimation of the system states and the faults are achieved with H∞ performance and formulated with a set of linear matrix inequalities (LMIs). The designed UIO is also applicable for fault diagnosis of singular delayed LPV systems with unmeasurable scheduling variables. The efficiency of the proposed approach is illustrated with an example.

Hierarchical Simulation to Assess Hardware and Software Dependability

NASA Technical Reports Server (NTRS)

Ries, Gregory Lawrence

1997-01-01

This thesis presents a method for conducting hierarchical simulations to assess system hardware and software dependability. The method is intended to model embedded microprocessor systems. A key contribution of the thesis is the idea of using fault dictionaries to propagate fault effects upward from the level of abstraction where a fault model is assumed to the system level where the ultimate impact of the fault is observed. A second important contribution is the analysis of the software behavior under faults as well as the hardware behavior. The simulation method is demonstrated and validated in four case studies analyzing Myrinet, a commercial, high-speed networking system. One key result from the case studies shows that the simulation method predicts the same fault impact 87.5% of the time as is obtained by similar fault injections into a real Myrinet system. Reasons for the remaining discrepancy are examined in the thesis. A second key result shows the reduction in the number of simulations needed due to the fault dictionary method. In one case study, 500 faults were injected at the chip level, but only 255 propagated to the system level. Of these 255 faults, 110 shared identical fault dictionary entries at the system level and so did not need to be resimulated. The necessary number of system-level simulations was therefore reduced from 500 to 145. Finally, the case studies show how the simulation method can be used to improve the dependability of the target system. The simulation analysis was used to add recovery to the target software for the most common fault propagation mechanisms that would cause the software to hang. After the modification, the number of hangs was reduced by 60% for fault injections into the real system.

Revisiting the 1912 Murefet, Turkey earthquake and tsunami

NASA Astrophysics Data System (ADS)

Baptista, M.; Aksoy, M. M.; Ferreira, H.; Ucarkus, G.; Meghraoui, M.; Çakir, Z.

2012-12-01

The 9 August 1912 Mürefte Earthquake M 7.4 is one of the largest destructive earthquakes of the 20th century, in the Balkan region. The tremor struck at 03:30 a.m. and was felt in a wide region including Greece and Bulgaria. The damage was localized in the western part of the Sea of Marmara, between Tekirdag and Çanakkale with maximum intenstiy IX-X MSK near the Mürefte village. The damage killed 2800 and injured 7000 people. It totally destroyed 12600 houses, damaged 12100 beyond repair and caused serious damage to another 15,400. The earthquake occurred on the westernmost segment of the North Anatolian Fault (NAF), limited by the Marmara Sea and the Aegean Sea on both ends. The event was accompanied with major surface faulting and co-seismic slip all along the on land and offshore sections. Up to date several faulting scenarios were proposed for this event claiming surface ruptures ranging from 50- 150 km. The tsunami reports of this event are scarce Contemporary accounts reported several onshore and offshore natural events that can be related to a tsunami caused by submarine surface faulting. Receding of the sea and inundations were observed along the northern shores of the Sea of Marmara. Besides, most of the coastal area of the Strait of the Dardanelles (Çanakkale) experienced flooding. Strong sea waves hit the northern coasts of Hayirsiz Ada and at Yesilköy (near Istanbul) a rowing-boat has been lifted up to a height of 2.7 m. In this study we present a summary of the tsunami observations and perform tsunami numerical simulations using a nonlinear shallow water code (NSLW7) that uses an explicit leap-frog finite difference scheme to solve the non-linear shallow water equations and high resolution DEM (Digital Earth Model) including bathymetry and topography in order to compute inundation. The initial condition of the tsunami propagation model is the static vertical displacement of the ocean floor due to the submarine earthquake that is computed Mansinha and Smylie (1971) homogenous elastic half space approach, as implemented in the Mirone suite (Luis, 2007). The parameters used in this computation are obtained by the earthquake fault geometry and slip distribution. The source is composed by 8 segments of variable length with dip angles varying between 70 to 850 and an average slip of 3 m. Preliminary results show maximum wave heights along the northern coast of the Marmara sea, Saros Gulf and Marmara Island according to the historical reports. This study was supported by Instituto Dom Luiz - LA, Universidade de Lisboa

Character and Significance of Surface Rupture Near the Intersection of the Denali and Totschunda Faults, M7.9 Denali Fault Earthquake, Alaska, November 3, 2002

NASA Astrophysics Data System (ADS)

Wallace, W. K.; Sherrod, B. L.; Dawson, T. E.

2002-12-01

Preliminary observations suggest that right-lateral strike-slip on the Denali fault is transferred to the Totschunda fault via an extensional bend in the Little Tok River valley. Most of the surface rupture during the Denali fault earthquake was along an east- to east-southeast striking, gently curved segment of the Denali fault. However, in the Little Tok River valley, rupture transferred to the southeast-striking Totschunda fault and continued to the southeast for another 75 km. West of the Little Tok River valley, 5-7 m of right-lateral slip and up to 2 m of vertical offset occurred on the main strand of the Denali fault, but no apparent displacement occurred on the Denali fault east of the valley. Rupture west of the intersection also occurred on multiple discontinuous strands parallel to and south of the main strand of the Denali fault. In the Little Tok River valley, the northern part of the Totschunda fault system consists of multiple discontinuous southeast-striking strands that are connected locally by south-striking stepover faults. Faults of the northern Totschunda system display 0-2.5 m of right-lateral slip and 0-2.75 m of vertical offset, with the largest vertical offset on a dominantly extensional stepover fault. The strands of the Totschunda system converge southeastward to a single strand that had up to 2 m of slip. Complex and discontinuous faulting may reflect in part the immaturity of the northern Totschunda system, which is known to be younger and have much less total slip than the Denali. The Totschunda fault forms an extensional bend relative to the dominantly right-lateral Denali fault to the west. The fault geometry and displacements at the intersection suggest that slip on the Denali fault during the earthquake was accommodated largely by extension in the northern Totschunda fault system, allowing a significant decrease in strike-slip relative to the Denali fault. Strands to the southwest in the area of the bend may represent shortcut faults that have reduced the curvature at the intersection of the two fault systems.

Comparative study of superconducting fault current limiter both for LCC-HVDC and VSC-HVDC systems

NASA Astrophysics Data System (ADS)

Lee, Jong-Geon; Khan, Umer Amir; Lim, Sung-Woo; Shin, Woo-ju; Seo, In-Jin; Lee, Bang-Wook

2015-11-01

High Voltage Direct Current (HVDC) system has been evaluated as the optimum solution for the renewable energy transmission and long-distance power grid connections. In spite of the various advantages of HVDC system, it still has been regarded as an unreliable system compared to AC system due to its vulnerable characteristics on the power system fault. Furthermore, unlike AC system, optimum protection and switching device has not been fully developed yet. Therefore, in order to enhance the reliability of the HVDC systems mitigation of power system fault and reliable fault current limiting and switching devices should be developed. In this paper, in order to mitigate HVDC fault, both for Line Commutated Converter HVDC (LCC-HVDC) and Voltage Source Converter HVDC (VSC-HVDC) system, an application of resistive superconducting fault current limiter which has been known as optimum solution to cope with the power system fault was considered. Firstly, simulation models for two types of LCC-HVDC and VSC-HVDC system which has point to point connection model were developed. From the designed model, fault current characteristics of faulty condition were analyzed. Second, application of SFCL on each types of HVDC system and comparative study of modified fault current characteristics were analyzed. Consequently, it was deduced that an application of AC-SFCL on LCC-HVDC system with point to point connection was desirable solution to mitigate the fault current stresses and to prevent commutation failure in HVDC electric power system interconnected with AC grid.

Intermittent/transient fault phenomena in digital systems

NASA Technical Reports Server (NTRS)

Masson, G. M.

1977-01-01

An overview of the intermittent/transient (IT) fault study is presented. An interval survivability evaluation of digital systems for IT faults is discussed along with a method for detecting and diagnosing IT faults in digital systems.

Distributed Fault-Tolerant Control of Networked Uncertain Euler-Lagrange Systems Under Actuator Faults.

PubMed

Chen, Gang; Song, Yongduan; Lewis, Frank L

2016-05-03

This paper investigates the distributed fault-tolerant control problem of networked Euler-Lagrange systems with actuator and communication link faults. An adaptive fault-tolerant cooperative control scheme is proposed to achieve the coordinated tracking control of networked uncertain Lagrange systems on a general directed communication topology, which contains a spanning tree with the root node being the active target system. The proposed algorithm is capable of compensating for the actuator bias fault, the partial loss of effectiveness actuation fault, the communication link fault, the model uncertainty, and the external disturbance simultaneously. The control scheme does not use any fault detection and isolation mechanism to detect, separate, and identify the actuator faults online, which largely reduces the online computation and expedites the responsiveness of the controller. To validate the effectiveness of the proposed method, a test-bed of multiple robot-arm cooperative control system is developed for real-time verification. Experiments on the networked robot-arms are conduced and the results confirm the benefits and the effectiveness of the proposed distributed fault-tolerant control algorithms.

A systematic way for the cost reduction of density fitting methods

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

Kállay, Mihály, E-mail: kallay@mail.bme.hu

2014-12-28

We present a simple approach for the reduction of the size of auxiliary basis sets used in methods exploiting the density fitting (resolution of identity) approximation for electron repulsion integrals. Starting out of the singular value decomposition of three-center two-electron integrals, new auxiliary functions are constructed as linear combinations of the original fitting functions. The new functions, which we term natural auxiliary functions (NAFs), are analogous to the natural orbitals widely used for the cost reduction of correlation methods. The use of the NAF basis enables the systematic truncation of the fitting basis, and thereby potentially the reduction of themore » computational expenses of the methods, though the scaling with the system size is not altered. The performance of the new approach has been tested for several quantum chemical methods. It is demonstrated that the most pronounced gain in computational efficiency can be expected for iterative models which scale quadratically with the size of the fitting basis set, such as the direct random phase approximation. The approach also has the promise of accelerating local correlation methods, for which the processing of three-center Coulomb integrals is a bottleneck.« less

Smart intimation and location of faults in distribution system

NASA Astrophysics Data System (ADS)

Hari Krishna, K.; Srinivasa Rao, B.

2018-04-01

Location of faults in the distribution system is one of the most complicated problems that we are facing today. Identification of fault location and severity of fault within a short time is required to provide continuous power supply but fault identification and information transfer to the operator is the biggest challenge in the distribution network. This paper proposes a fault location method in the distribution system based on Arduino nano and GSM module with flame sensor. The main idea is to locate the fault in the distribution transformer by sensing the arc coming out from the fuse element. The biggest challenge in the distribution network is to identify the location and the severity of faults under different conditions. Well operated transmission and distribution systems will play a key role for uninterrupted power supply. Whenever fault occurs in the distribution system the time taken to locate and eliminate the fault has to be reduced. The proposed design was achieved with flame sensor and GSM module. Under faulty condition, the system will automatically send an alert message to the operator in the distribution system, about the abnormal conditions near the transformer, site code and its exact location for possible power restoration.

Seismic interpretation of the deep structure of the Wabash Valley Fault System

USGS Publications Warehouse

Bear, G.W.; Rupp, J.A.; Rudman, A.J.

1997-01-01

Interpretations of newly available seismic reflection profiles near the center of the Illinois Basin indicate that the Wabash Valley Fault System is rooted in a series of basement-penetrating faults. The fault system is composed predominantly of north-northeast-trending high-angle normal faults. The largest faults in the system bound the 22-km wide 40-km long Grayville Graben. Structure contour maps drawn on the base of the Mount Simon Sandstone (Cambrian System) and a deeper pre-Mount Simon horizon show dip-slip displacements totaling at least 600 meters across the New Harmony fault. In contrast to previous interpretations, the N-S extent of significant fault offsets is restricted to a region north of 38?? latitude and south of 38.35?? latitude. This suggests that the graben is not a NE extension of the structural complex composed of the Rough Creek Fault System and the Reelfoot Rift as previously interpreted. Structural complexity on the graben floor also decreases to the south. Structural trends north of 38?? latitude are offset laterally across several large faults, indicating strike-slip motions of 2 to 4 km. Some of the major faults are interpreted to penetrate to depths of 7 km or more. Correlation of these faults with steep potential field gradients suggests that the fault positions are controlled by major lithologic contacts within the basement and that the faults may extend into the depth range where earthquakes are generated, revealing a potential link between specific faults and recently observed low-level seismicity in the area.

Advanced Ground Systems Maintenance Functional Fault Models For Fault Isolation Project

NASA Technical Reports Server (NTRS)

Perotti, Jose M. (Compiler)

2014-01-01

This project implements functional fault models (FFM) to automate the isolation of failures during ground systems operations. FFMs will also be used to recommend sensor placement to improve fault isolation capabilities. The project enables the delivery of system health advisories to ground system operators.

Recent deformation along the offshore Malibu Coast, Dume, and related faults west of Point Dume, southern California

USGS Publications Warehouse

Fisher, M.A.; Langenheim, V.E.; Sorlien, C.C.; Dartnell, P.; Sliter, R.W.; Cochrane, G.R.; Wong, F.L.

2005-01-01

Offshore faults west of Point Dume, southern California, are part of an important regional fault system that extends for about 206 km, from near the city of Los Angeles westward along the south flank of the Santa Monica Mountains and through the northern Channel Islands. This boundary fault system separates the western Transverse Ranges, on the north, from the California Continental Borderland, on the south. Previous research showed that the fault system includes many active fault strands; consequently, the entire system is considered a serious potential earthquake hazard to nearby Los Angeles. We present an integrated analysis of multichannel seismic- and high-resolution seismic-reflection data and multibeam-bathymetric information to focus on the central part of the fault system that lies west of Point Dume. We show that some of the main offshore faults have cumulative displacements of 3-5 km, and many faults are currently active because they deform the seafloor or very shallow sediment layers. The main offshore fault is the Dume fault, a large north-dipping reverse fault. In the eastern part of the study area, this fault offsets the seafloor, showing Holocene displacement. Onshore, the Malibu Coast fault dips steeply north, is active, and shows left-oblique slip. The probable offshore extension of this fault is a large fault that dips steeply in its upper part but flattens at depth. High-resolution seismic data show that this fault deforms shallow sediment making up the Hueneme fan complex, indicating Holocene activity. A structure near Sycamore knoll strikes transversely to the main faults and could be important to the analysis of the regional earthquake hazard because the structure might form a boundary between earthquake-rupture segments.

Activation of preexisting transverse structures in an evolving magmatic rift in East Africa

NASA Astrophysics Data System (ADS)

Muirhead, J. D.; Kattenhorn, S. A.

2018-01-01

Inherited crustal weaknesses have long been recognized as important factors in strain localization and basin development in the East African Rift System (EARS). However, the timing and kinematics (e.g., sense of slip) of transverse (rift-oblique) faults that exploit these weaknesses are debated, and thus the roles of inherited weaknesses at different stages of rift basin evolution are often overlooked. The mechanics of transverse faulting were addressed through an analysis of the Kordjya fault of the Magadi basin (Kenya Rift). Fault kinematics were investigated from field and remote-sensing data collected on fault and joint systems. Our analysis indicates that the Kordjya fault consists of a complex system of predominantly NNE-striking, rift-parallel fault segments that collectively form a NNW-trending array of en echelon faults. The transverse Kordjya fault therefore reactivated existing rift-parallel faults in ∼1 Ma lavas as oblique-normal faults with a component of sinistral shear. In all, these fault motions accommodate dip-slip on an underlying transverse structure that exploits the Aswa basement shear zone. This study shows that transverse faults may be activated through a complex interplay among magma-assisted strain localization, preexisting structures, and local stress rotations. Rather than forming during rift initiation, transverse structures can develop after the establishment of pervasive rift-parallel fault systems, and may exhibit dip-slip kinematics when activated from local stress rotations. The Kordjya fault is shown here to form a kinematic linkage that transfers strain to a newly developing center of concentrated magmatism and normal faulting. It is concluded that recently activated transverse faults not only reveal the effects of inherited basement weaknesses on fault development, but also provide important clues regarding developing magmatic and tectonic systems as young continental rift basins evolve.

Fault management for data systems

NASA Technical Reports Server (NTRS)

Boyd, Mark A.; Iverson, David L.; Patterson-Hine, F. Ann

1993-01-01

Issues related to automating the process of fault management (fault diagnosis and response) for data management systems are considered. Substantial benefits are to be gained by successful automation of this process, particularly for large, complex systems. The use of graph-based models to develop a computer assisted fault management system is advocated. The general problem is described and the motivation behind choosing graph-based models over other approaches for developing fault diagnosis computer programs is outlined. Some existing work in the area of graph-based fault diagnosis is reviewed, and a new fault management method which was developed from existing methods is offered. Our method is applied to an automatic telescope system intended as a prototype for future lunar telescope programs. Finally, an application of our method to general data management systems is described.

The stress shadow effect: a mechanical analysis of the evenly-spaced parallel strike-slip faults in the San Andreas fault system

NASA Astrophysics Data System (ADS)

Zuza, A. V.; Yin, A.; Lin, J. C.

2015-12-01

Parallel evenly-spaced strike-slip faults are prominent in the southern San Andreas fault system, as well as other settings along plate boundaries (e.g., the Alpine fault) and within continental interiors (e.g., the North Anatolian, central Asian, and northern Tibetan faults). In southern California, the parallel San Jacinto, Elsinore, Rose Canyon, and San Clemente faults to the west of the San Andreas are regularly spaced at ~40 km. In the Eastern California Shear Zone, east of the San Andreas, faults are spaced at ~15 km. These characteristic spacings provide unique mechanical constraints on how the faults interact. Despite the common occurrence of parallel strike-slip faults, the fundamental questions of how and why these fault systems form remain unanswered. We address this issue by using the stress shadow concept of Lachenbruch (1961)—developed to explain extensional joints by using the stress-free condition on the crack surface—to present a mechanical analysis of the formation of parallel strike-slip faults that relates fault spacing and brittle-crust thickness to fault strength, crustal strength, and the crustal stress state. We discuss three independent models: (1) a fracture mechanics model, (2) an empirical stress-rise function model embedded in a plastic medium, and (3) an elastic-plate model. The assumptions and predictions of these models are quantitatively tested using scaled analogue sandbox experiments that show that strike-slip fault spacing is linearly related to the brittle-crust thickness. We derive constraints on the mechanical properties of the southern San Andreas strike-slip faults and fault-bounded crust (e.g., local fault strength and crustal/regional stress) given the observed fault spacing and brittle-crust thickness, which is obtained by defining the base of the seismogenic zone with high-resolution earthquake data. Our models allow direct comparison of the parallel faults in the southern San Andreas system with other similar strike-slip fault systems, both on Earth and throughout the solar system (e.g., the Tiger Stripe Fractures on Enceladus).

Neotectonics and geomorphic evolution of the northwestern arm of the Yellowstone Tectonic Parabola: Controls on intra-cratonic extensional regimes, southwest Montana

USGS Publications Warehouse

Ruleman, Chester A.; Larsen, Mort; Stickney, Michael C.

2014-01-01

The catastrophic Hebgen Lake earthquake of 18 August 1959 (MW 7.3) led many geoscientists to develop new methods to better understand active tectonics in extensional tectonic regimes that address seismic hazards. The Madison Range fault system and adjacent Hebgen Lake–Red Canyon fault system provide an intermountain active tectonic analog for regional analyses of extensional crustal deformation. The Madison Range fault system comprises fault zones (~100 km in length) that have multiple salients and embayments marked by preexisting structures exposed in the footwall. Quaternary tectonic activity rates differ along the length of the fault system, with less displacement to the north. Within the Hebgen Lake basin, the 1959 earthquake is the latest slip event in the Hebgen Lake–Red Canyon fault system and southern Madison Range fault system. Geomorphic and paleoseismic investigations indicate previous faulting events on both fault systems. Surficial geologic mapping and historic seismicity support a coseismic structural linkage between the Madison Range and Hebgen Lake–Red Canyon fault systems. On this trip, we will look at Quaternary surface ruptures that characterize prehistoric earthquake magnitudes. The one-day field trip begins and ends in Bozeman, and includes an overview of the active tectonics within the Madison Valley and Hebgen Lake basin, southwestern Montana. We will also review geologic evidence, which includes new geologic maps and geomorphic analyses that demonstrate preexisting structural controls on surface rupture patterns along the Madison Range and Hebgen Lake–Red Canyon fault systems.

Software-implemented fault insertion: An FTMP example

NASA Technical Reports Server (NTRS)

Czeck, Edward W.; Siewiorek, Daniel P.; Segall, Zary Z.

1987-01-01

This report presents a model for fault insertion through software; describes its implementation on a fault-tolerant computer, FTMP; presents a summary of fault detection, identification, and reconfiguration data collected with software-implemented fault insertion; and compares the results to hardware fault insertion data. Experimental results show detection time to be a function of time of insertion and system workload. For the fault detection time, there is no correlation between software-inserted faults and hardware-inserted faults; this is because hardware-inserted faults must manifest as errors before detection, whereas software-inserted faults immediately exercise the error detection mechanisms. In summary, the software-implemented fault insertion is able to be used as an evaluation technique for the fault-handling capabilities of a system in fault detection, identification and recovery. Although the software-inserted faults do not map directly to hardware-inserted faults, experiments show software-implemented fault insertion is capable of emulating hardware fault insertion, with greater ease and automation.

Abstractions for Fault-Tolerant Distributed System Verification

NASA Technical Reports Server (NTRS)

Pike, Lee S.; Maddalon, Jeffrey M.; Miner, Paul S.; Geser, Alfons

2004-01-01

Four kinds of abstraction for the design and analysis of fault tolerant distributed systems are discussed. These abstractions concern system messages, faults, fault masking voting, and communication. The abstractions are formalized in higher order logic, and are intended to facilitate specifying and verifying such systems in higher order theorem provers.

Duplex development and abandonment during evolution of the Lewis thrust system, southern Glacier National Park, Montana

NASA Astrophysics Data System (ADS)

Yin, An; Kelty, Thomas K.; Davis, Gregory A.

1989-09-01

Geologic mapping in southern Glacier National Park, Montana, reveals the presence of two duplexes sharing the same floor thrust fault, the Lewis thrust. The westernmost duplex (Brave Dog Mountain) includes the low-angle Brave Dog roof fault and Elk Mountain imbricate system, and the easternmost (Rising Wolf Mountain) duplex includes the low-angle Rockwell roof fault and Mt. Henry imbricate system. The geometry of these duplexes suggests that they differ from previously described geometric-kinematic models for duplex development. Their low-angle roof faults were preexisting structures that were locally utilized as roof faults during the formation of the imbricate systems. Crosscutting of the Brave Dog fault by the Mt. Henry imbricate system indicates that the two duplexes formed at different times. The younger Rockwell-Mt. Henry duplex developed 20 km east of the older Brave Dog-Elk Mountain duplex; the roof fault of the former is at a higher structural level. Field relations confirm that the low-angle Rockwell fault existed across the southern Glacier Park area prior to localized formation of the Mt. Henry imbricate thrusts beneath it. These thrusts kinematically link the Rockwell and Lewis faults and may be analogous to P shears that form between two synchronously active faults bounding a simple shear system. The abandonment of one duplex and its replacement by another with a new and higher roof fault may have been caused by (1) warping of the older and lower Brave Dog roof fault during the formation of the imbricate system (Elk Mountain) beneath it, (2) an upward shifting of the highest level of a simple shear system in the Lewis plate to a new decollement level in subhorizontal belt strata (= the Rockwell fault) that lay above inclined strata within the first duplex, and (3) a reinitiation of P-shear development (= Mt. Henry imbricate faults) between the Lewis thrust and the subparallel, synkinematic Rockwell fault.

An information transfer based novel framework for fault root cause tracing of complex electromechanical systems in the processing industry

NASA Astrophysics Data System (ADS)

Wang, Rongxi; Gao, Xu; Gao, Jianmin; Gao, Zhiyong; Kang, Jiani

2018-02-01

As one of the most important approaches for analyzing the mechanism of fault pervasion, fault root cause tracing is a powerful and useful tool for detecting the fundamental causes of faults so as to prevent any further propagation and amplification. Focused on the problems arising from the lack of systematic and comprehensive integration, an information transfer-based novel data-driven framework for fault root cause tracing of complex electromechanical systems in the processing industry was proposed, taking into consideration the experience and qualitative analysis of conventional fault root cause tracing methods. Firstly, an improved symbolic transfer entropy method was presented to construct a directed-weighted information model for a specific complex electromechanical system based on the information flow. Secondly, considering the feedback mechanisms in the complex electromechanical systems, a method for determining the threshold values of weights was developed to explore the disciplines of fault propagation. Lastly, an iterative method was introduced to identify the fault development process. The fault root cause was traced by analyzing the changes in information transfer between the nodes along with the fault propagation pathway. An actual fault root cause tracing application of a complex electromechanical system is used to verify the effectiveness of the proposed framework. A unique fault root cause is obtained regardless of the choice of the initial variable. Thus, the proposed framework can be flexibly and effectively used in fault root cause tracing for complex electromechanical systems in the processing industry, and formulate the foundation of system vulnerability analysis and condition prediction, as well as other engineering applications.

FAULT PROPAGATION AND EFFECTS ANALYSIS FOR DESIGNING AN ONLINE MONITORING SYSTEM FOR THE SECONDARY LOOP OF A NUCLEAR POWER PLANT PART OF A HYBRID ENERGY SYSTEM

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

Li, Huijuan; Diao, Xiaoxu; Li, Boyuan

This paper studies the propagation and effects of faults of critical components that pertain to the secondary loop of a nuclear power plant found in Nuclear Hybrid Energy Systems (NHES). This information is used to design an on-line monitoring (OLM) system which is capable of detecting and forecasting faults that are likely to occur during NHES operation. In this research, the causes, features, and effects of possible faults are investigated by simulating the propagation of faults in the secondary loop. The simulation is accomplished by using the Integrated System Failure Analysis (ISFA). ISFA is used for analyzing hardware and softwaremore » faults during the conceptual design phase. In this paper, the models of system components required by ISFA are initially constructed. Then, the fault propagation analysis is implemented, which is conducted under the bounds set by acceptance criteria derived from the design of an OLM system. The result of the fault simulation is utilized to build a database for fault detection and diagnosis, provide preventive measures, and propose an optimization plan for the OLM system.« less

Clustering of GPS velocities in the Mojave Block, southeastern California

USGS Publications Warehouse

Savage, James C.; Simpson, Robert W.

2013-01-01

We find subdivisions within the Mojave Block using cluster analysis to identify groupings in the velocities observed at GPS stations there. The clusters are represented on a fault map by symbols located at the positions of the GPS stations, each symbol representing the cluster to which the velocity of that GPS station belongs. Fault systems that separate the clusters are readily identified on such a map. The most significant representation as judged by the gap test involves 4 clusters within the Mojave Block. The fault systems bounding the clusters from east to west are 1) the faults defining the eastern boundary of the Northeast Mojave Domain extended southward to connect to the Hector Mine rupture, 2) the Calico-Paradise fault system, 3) the Landers-Blackwater fault system, and 4) the Helendale-Lockhart fault system. This division of the Mojave Block is very similar to that proposed by Meade and Hager. However, no cluster boundary coincides with the Garlock Fault, the northern boundary of the Mojave Block. Rather, the clusters appear to continue without interruption from the Mojave Block north into the southern Walker Lane Belt, similar to the continuity across the Garlock Fault of the shear zone along the Blackwater-Little Lake fault system observed by Peltzer et al. Mapped traces of individual faults in the Mojave Block terminate within the block and do not continue across the Garlock Fault [Dokka and Travis, ].

Improving Multiple Fault Diagnosability using Possible Conflicts

NASA Technical Reports Server (NTRS)

Daigle, Matthew J.; Bregon, Anibal; Biswas, Gautam; Koutsoukos, Xenofon; Pulido, Belarmino

2012-01-01

Multiple fault diagnosis is a difficult problem for dynamic systems. Due to fault masking, compensation, and relative time of fault occurrence, multiple faults can manifest in many different ways as observable fault signature sequences. This decreases diagnosability of multiple faults, and therefore leads to a loss in effectiveness of the fault isolation step. We develop a qualitative, event-based, multiple fault isolation framework, and derive several notions of multiple fault diagnosability. We show that using Possible Conflicts, a model decomposition technique that decouples faults from residuals, we can significantly improve the diagnosability of multiple faults compared to an approach using a single global model. We demonstrate these concepts and provide results using a multi-tank system as a case study.

Geophysical Characterization of the Hilton Creek Fault System

NASA Astrophysics Data System (ADS)

Lacy, A. K.; Macy, K. P.; De Cristofaro, J. L.; Polet, J.

2016-12-01

The Long Valley Caldera straddles the eastern edge of the Sierra Nevada Batholith and the western edge of the Basin and Range Province, and represents one of the largest caldera complexes on Earth. The caldera is intersected by numerous fault systems, including the Hartley Springs Fault System, the Round Valley Fault System, the Long Valley Ring Fault System, and the Hilton Creek Fault System, which is our main region of interest. The Hilton Creek Fault System appears as a single NW-striking fault, dipping to the NE, from Davis Lake in the south to the southern rim of the Long Valley Caldera. Inside the caldera, it splays into numerous parallel faults that extend toward the resurgent dome. Seismicity in the area increased significantly in May 1980, following a series of large earthquakes in the vicinity of the caldera and a subsequent large earthquake swarm which has been suggested to be the result of magma migration. A large portion of the earthquake swarms in the Long Valley Caldera occurs on or around the Hilton Creek Fault splays. We are conducting an interdisciplinary geophysical study of the Hilton Creek Fault System from just south of the onset of splay faulting, to its extension into the dome of the caldera. Our investigation includes ground-based magnetic field measurements, high-resolution total station elevation profiles, Structure-From-Motion derived topography and an analysis of earthquake focal mechanisms and statistics. Preliminary analysis of topographic profiles, of approximately 1 km in length, reveals the presence of at least three distinct fault splays within the caldera with vertical offsets of 0.5 to 1.0 meters. More detailed topographic mapping is expected to highlight smaller structures. We are also generating maps of the variation in b-value along different portions of the Hilton Creek system to determine whether we can detect any transition to more swarm-like behavior towards the North. We will show maps of magnetic anomalies, topography, various models of the Hilton Creek Fault System and cross-sections through focal mechanism and earthquake catalogs, and will attempt to integrate these observations into a single fault geometry model.

Active faulting, earthquakes, and restraining bend development near Kerman city in southeastern Iran

NASA Astrophysics Data System (ADS)

Walker, Richard Thomas; Talebian, Morteza; Saiffori, Sohei; Sloan, Robert Alastair; Rasheedi, Ali; MacBean, Natasha; Ghassemi, Abbas

2010-08-01

We provide descriptions of strike-slip and reverse faulting, active within the late Quaternary, in the vicinity of Kerman city in southeastern Iran. The faults accommodate north-south, right-lateral, shear between central Iran and the Dasht-e-Lut depression. The regions that we describe have been subject to numerous earthquakes in the historical and instrumental periods, and many of the faults that are documented in this paper constitute hazards for local populations, including the city of Kerman itself (population ˜200,000). Faults to the north and east of Kerman are associated with the transfer of slip from the Gowk to the Kuh Banan right-lateral faults across a 40 km-wide restraining bend. Faults south and west of the city are associated with oblique slip on the Mahan and Jorjafk systems. The patterns of faulting observed along the Mahan-Jorjafk system, the Gowk-Kuh Banan system, and also the Rafsanjan-Rayen system further to the south, appear to preserve different stages in the development of these oblique-slip fault systems. We suggest that the faulting evolves through time. Topography is initially generated on oblique slip faults (as is seen on the Jorjafk fault). The shortening component then migrates to reverse faults situated away from the high topography whereas strike-slip continues to be accommodated in the high, mountainous, regions (as is seen, for example, on the Rafsanjan fault). The reverse faults may then link together and eventually evolve into new, through-going, strike-slip faults in a process that appears to be occurring, at present, in the bend between the Gowk and Kuh Banan faults.

AGSM Functional Fault Models for Fault Isolation Project

NASA Technical Reports Server (NTRS)

Harp, Janicce Leshay

2014-01-01

This project implements functional fault models to automate the isolation of failures during ground systems operations. FFMs will also be used to recommend sensor placement to improve fault isolation capabilities. The project enables the delivery of system health advisories to ground system operators.

Data-based fault-tolerant control for affine nonlinear systems with actuator faults.

PubMed

Xie, Chun-Hua; Yang, Guang-Hong

2016-09-01

This paper investigates the fault-tolerant control (FTC) problem for unknown nonlinear systems with actuator faults including stuck, outage, bias and loss of effectiveness. The upper bounds of stuck faults, bias faults and loss of effectiveness faults are unknown. A new data-based FTC scheme is proposed. It consists of the online estimations of the bounds and a state-dependent function. The estimations are adjusted online to compensate automatically the actuator faults. The state-dependent function solved by using real system data helps to stabilize the system. Furthermore, all signals in the resulting closed-loop system are uniformly bounded and the states converge asymptotically to zero. Compared with the existing results, the proposed approach is data-based. Finally, two simulation examples are provided to show the effectiveness of the proposed approach. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Validation techniques for fault emulation of SRAM-based FPGAs

DOE PAGES

Quinn, Heather; Wirthlin, Michael

2015-08-07

A variety of fault emulation systems have been created to study the effect of single-event effects (SEEs) in static random access memory (SRAM) based field-programmable gate arrays (FPGAs). These systems are useful for augmenting radiation-hardness assurance (RHA) methodologies for verifying the effectiveness for mitigation techniques; understanding error signatures and failure modes in FPGAs; and failure rate estimation. For radiation effects researchers, it is important that these systems properly emulate how SEEs manifest in FPGAs. If the fault emulation systems does not mimic the radiation environment, the system will generate erroneous data and incorrect predictions of behavior of the FPGA inmore » a radiation environment. Validation determines whether the emulated faults are reasonable analogs to the radiation-induced faults. In this study we present methods for validating fault emulation systems and provide several examples of validated FPGA fault emulation systems.« less

Fault-tolerant cooperative output regulation for multi-vehicle systems with sensor faults

NASA Astrophysics Data System (ADS)

Qin, Liguo; He, Xiao; Zhou, D. H.

2017-10-01

This paper presents a unified framework of fault diagnosis and fault-tolerant cooperative output regulation (FTCOR) for a linear discrete-time multi-vehicle system with sensor faults. The FTCOR control law is designed through three steps. A cooperative output regulation (COR) controller is designed based on the internal mode principle when there are no sensor faults. A sufficient condition on the existence of the COR controller is given based on the discrete-time algebraic Riccati equation (DARE). Then, a decentralised fault diagnosis scheme is designed to cope with sensor faults occurring in followers. A residual generator is developed to detect sensor faults of each follower, and a bank of fault-matching estimators are proposed to isolate and estimate sensor faults of each follower. Unlike the current distributed fault diagnosis for multi-vehicle systems, the presented decentralised fault diagnosis scheme in each vehicle reduces the communication and computation load by only using the information of the vehicle. By combing the sensor fault estimation and the COR control law, an FTCOR controller is proposed. Finally, the simulation results demonstrate the effectiveness of the FTCOR controller.

Previously unrecognized now-inactive strand of the North Anatolian fault in the Thrace basin

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

Perincek, D.

1988-08-01

The North Anatolian fault is a major 1,200 km-long transform fault bounding the Anatolian plate to the north. It formed in late middle Miocene time as a broad shear zone with a number of strands splaying westward in a horsetail fashion. Later, movement became localized along the stem, and the southerly and northerly splays became inactive. One such right-lateral, now-inactive splay is the west-northwest-striking Thrace strike-slip fault system, consisting of three subparallel strike-slip faults. From north to south these are the Kirklareli, Lueleburgaz, and Babaeski fault zones, extending {plus minus} 130 km along the strike. The Thrace fault zone probablymore » connected with the presently active northern strand of the North Anatolian fault in the Sea of Marmara in the southeast and may have joined the Plovdiv graben zone in Bulgaria in the northwest. The Thrace basin in which the Thrace fault system is located, is Cenozoic with a sedimentary basin fill from middle Eocene to Pliocene. The Thrace fault system formed in pre-Pliocene time and had become inactive by the Pliocene. Strike-slip fault zones with normal and reverse separation are detected by seismic reflection profiles and subsurface data. Releasing bend extensional structures (e.g., near the town of Lueleburgaz) and restraining bend compressional structures (near Vakiflar-1 well) are abundant on the fault zones. Umurca and Hamitabad fields are en echelon structures on the Lueleburgaz fault zone. The Thrace strike-slip fault system has itself a horsetail shape, the various strands of which become younger southward. The entire system died before the Pliocene, and motion on the North Anatolian fault zone began to be accommodated in the Sea of Marmara region. Thus the Thrace fault system represents the oldest strand of the North Anatolian fault in the west.« less

Magma-tectonic Interaction at Laguna del Maule, Chile

NASA Astrophysics Data System (ADS)

Keranen, K. M.; Peterson, D. E.; Miller, C. A.; Garibaldi, N.; Tikoff, B.; Williams-Jones, G.

2016-12-01

The Laguna del Maule Volcanic Field (LdM), Chile, the largest concentration of rhyolite <20 kyr globally, exhibits crustal deformation at rates higher than any non-erupting volcano. The interaction of large magmatic systems with faulting is poorly understood, however, the Chaitén rhyolitic system demonstrated that faults can serve as magma pathways during an eruption. We present a complex fault system at LdM in close proximity to the magma reservoir. In March 2016, 18 CHIRP seismic reflection lines were acquired at LdM to identify faults and analyze potential spatial and temporal impacts of the fault system on volcanic activity. We mapped three key horizons on each line, bounding sediment packages between Holocene onset, 870 ybp, and the present date. Faults were mapped on each line and offset was calculated across key horizons. Our results indicate a system of normal-component faults in the northern lake sector, striking subparallel to the mapped Troncoso Fault SW of the lake. These faults correlate to prominent magnetic lineations mapped by boat magnetic data acquired February 2016 which are interpreted as dykes intruding along faults. We also imaged a vertical fault, interpreted as a strike-slip fault, and a series of normal faults in the SW lake sector near the center of magmatic inflation. Isochron and fault offset maps illuminate areas of growth strata and indicate migration and increase of fault activity from south to north through time. We identify a domal structure in the SW lake sector, coincident with an area of low magnetization, in the region of maximum deformation from InSAR results. The dome experienced 10 ms TWT ( 10 meters) of uplift throughout the past 16 kybp, which we interpret as magmatic inflation in a shallow magma reservoir. This inflation is isolated to a 1.5 km diameter region in the hanging wall of the primary normal fault system, indicating possible fault-facilitated inflation.

Evolution of the Rodgers Creek–Maacama right-lateral fault system and associated basins east of the northward-migrating Mendocino Triple Junction, northern California

USGS Publications Warehouse

McLaughlin, Robert J.; Sarna-Wojcicki, Andrei M.; Wagner, David L.; Fleck, Robert J.; Langenheim, V.E.; Jachens, Robert C.; Clahan, Kevin; Allen, James R.

2012-01-01

The Rodgers Creek–Maacama fault system in the northern California Coast Ranges (United States) takes up substantial right-lateral motion within the wide transform boundary between the Pacific and North American plates, over a slab window that has opened northward beneath the Coast Ranges. The fault system evolved in several right steps and splays preceded and accompanied by extension, volcanism, and strike-slip basin development. Fault and basin geometries have changed with time, in places with younger basins and faults overprinting older structures. Along-strike and successional changes in fault and basin geometry at the southern end of the fault system probably are adjustments to frequent fault zone reorganizations in response to Mendocino Triple Junction migration and northward transit of a major releasing bend in the northern San Andreas fault. The earliest Rodgers Creek fault zone displacement is interpreted to have occurred ca. 7 Ma along extensional basin-forming faults that splayed northwest from a west-northwest proto-Hayward fault zone, opening a transtensional basin west of Santa Rosa. After ca. 5 Ma, the early transtensional basin was compressed and extensional faults were reactivated as thrusts that uplifted the northeast side of the basin. After ca. 2.78 Ma, the Rodgers Creek fault zone again splayed from the earlier extensional and thrust faults to steeper dipping faults with more north-northwest orientations. In conjunction with the changes in orientation and slip mode, the Rodgers Creek fault zone dextral slip rate increased from ∼2–4 mm/yr 7–3 Ma, to 5–8 mm/yr after 3 Ma. The Maacama fault zone is shown from several data sets to have initiated ca. 3.2 Ma and has slipped right-laterally at ∼5–8 mm/yr since its initiation. The initial Maacama fault zone splayed northeastward from the south end of the Rodgers Creek fault zone, accompanied by the opening of several strike-slip basins, some of which were later uplifted and compressed during late-stage fault zone reorganization. The Santa Rosa pull-apart basin formed ca. 1 Ma, during the reorganization of the right stepover geometry of the Rodgers Creek–Maacama fault system, when the maturely evolved overlapping geometry of the northern Rodgers Creek and Maacama fault zones was overprinted by a less evolved, non-overlapping stepover geometry. The Rodgers Creek–Maacama fault system has contributed at least 44–53 km of right-lateral displacement to the East Bay fault system south of San Pablo Bay since 7 Ma, at a minimum rate of 6.1–7.8 mm/yr.

Structural styles of Paleozoic intracratonic fault reactivation: A case study of the Grays Point fault zone in southeastern Missouri, USA

USGS Publications Warehouse

Clendenin, C.W.; Diehl, S.F.

1999-01-01

A pronounced, subparallel set of northeast-striking faults occurs in southeastern Missouri, but little is known about these faults because of poor exposure. The Commerce fault system is the southernmost exposed fault system in this set and has an ancestry related to Reelfoot rift extension. Recent published work indicates that this fault system has a long history of reactivation. The northeast-striking Grays Point fault zone is a segment of the Commerce fault system and is well exposed along the southeast rim of an inactive quarry. Our mapping shows that the Grays Point fault zone also has a complex history of polyphase reactivation, involving three periods of Paleozoic reactivation that occurred in Late Ordovician, Devonian, and post-Mississippian. Each period is characterized by divergent, right-lateral oblique-slip faulting. Petrographic examination of sidwall rip-out clasts in calcite-filled faults associated with the Grays Point fault zone supports a minimum of three periods of right-lateral oblique-slip. The reported observations imply that a genetic link exists between intracratonic fault reactivation and strain produced by Paleozoic orogenies affecting the eastern margin of Laurentia (North America). Interpretation of this link indicate that right-lateral oblique-slip has occurred on all of the northeast-striking faults in southeastern Missouri as a result of strain influenced by the convergence directions of the different Paleozoic orogenies.

Managing Space System Faults: Coalescing NASA's Views

NASA Technical Reports Server (NTRS)

Muirhead, Brian; Fesq, Lorraine

2012-01-01

Managing faults and their resultant failures is a fundamental and critical part of developing and operating aerospace systems. Yet, recent studies have shown that the engineering "discipline" required to manage faults is not widely recognized nor evenly practiced within the NASA community. Attempts to simply name this discipline in recent years has been fraught with controversy among members of the Integrated Systems Health Management (ISHM), Fault Management (FM), Fault Protection (FP), Hazard Analysis (HA), and Aborts communities. Approaches to managing space system faults typically are unique to each organization, with little commonality in the architectures, processes and practices across the industry.

Provable Transient Recovery for Frame-Based, Fault-Tolerant Computing Systems

NASA Technical Reports Server (NTRS)

DiVito, Ben L.; Butler, Ricky W.

1992-01-01

We present a formal verification of the transient fault recovery aspects of the Reliable Computing Platform (RCP), a fault-tolerant computing system architecture for digital flight control applications. The RCP uses NMR-style redundancy to mask faults and internal majority voting to purge the effects of transient faults. The system design has been formally specified and verified using the EHDM verification system. Our formalization accommodates a wide variety of voting schemes for purging the effects of transients.

Automatic Detection of Electric Power Troubles (ADEPT)

NASA Technical Reports Server (NTRS)

Wang, Caroline; Zeanah, Hugh; Anderson, Audie; Patrick, Clint; Brady, Mike; Ford, Donnie

1988-01-01

ADEPT is an expert system that integrates knowledge from three different suppliers to offer an advanced fault-detection system, and is designed for two modes of operation: real-time fault isolation and simulated modeling. Real time fault isolation of components is accomplished on a power system breadboard through the Fault Isolation Expert System (FIES II) interface with a rule system developed in-house. Faults are quickly detected and displayed and the rules and chain of reasoning optionally provided on a Laser printer. This system consists of a simulated Space Station power module using direct-current power supplies for Solar arrays on three power busses. For tests of the system's ability to locate faults inserted via switches, loads are configured by an INTEL microcomputer and the Symbolics artificial intelligence development system. As these loads are resistive in nature, Ohm's Law is used as the basis for rules by which faults are located. The three-bus system can correct faults automatically where there is a surplus of power available on any of the three busses. Techniques developed and used can be applied readily to other control systems requiring rapid intelligent decisions. Simulated modelling, used for theoretical studies, is implemented using a modified version of Kennedy Space Center's KATE (Knowledge-Based Automatic Test Equipment), FIES II windowing, and an ADEPT knowledge base. A load scheduler and a fault recovery system are currently under development to support both modes of operation.

Integrated Fault Diagnosis Algorithm for Motor Sensors of In-Wheel Independent Drive Electric Vehicles.

PubMed

Jeon, Namju; Lee, Hyeongcheol

2016-12-12

An integrated fault-diagnosis algorithm for a motor sensor of in-wheel independent drive electric vehicles is presented. This paper proposes a method that integrates the high- and low-level fault diagnoses to improve the robustness and performance of the system. For the high-level fault diagnosis of vehicle dynamics, a planar two-track non-linear model is first selected, and the longitudinal and lateral forces are calculated. To ensure redundancy of the system, correlation between the sensor and residual in the vehicle dynamics is analyzed to detect and separate the fault of the drive motor system of each wheel. To diagnose the motor system for low-level faults, the state equation of an interior permanent magnet synchronous motor is developed, and a parity equation is used to diagnose the fault of the electric current and position sensors. The validity of the high-level fault-diagnosis algorithm is verified using Carsim and Matlab/Simulink co-simulation. The low-level fault diagnosis is verified through Matlab/Simulink simulation and experiments. Finally, according to the residuals of the high- and low-level fault diagnoses, fault-detection flags are defined. On the basis of this information, an integrated fault-diagnosis strategy is proposed.

Neotectonics of interior Alaska and the late Quaternary slip rate along the Denali fault system

USGS Publications Warehouse

Haeussler, Peter J.; Matmon, Ari; Schwartz, David P.; Seitz, Gordon G.

2017-01-01

The neotectonics of southern Alaska (USA) are characterized by a several hundred kilometers–wide zone of dextral transpressional that spans the Alaska Range. The Denali fault system is the largest active strike-slip fault system in interior Alaska, and it produced a Mw 7.9 earthquake in 2002. To evaluate the late Quaternary slip rate on the Denali fault system, we collected samples for cosmogenic surface exposure dating from surfaces offset by the fault system. This study includes data from 107 samples at 19 sites, including 7 sites we previously reported, as well as an estimated slip rate at another site. We utilize the interpreted surface ages to provide estimated slip rates. These new slip rate data confirm that the highest late Quaternary slip rate is ∼13 mm/yr on the central Denali fault near its intersection with the eastern Denali and the Totschunda faults, with decreasing slip rate both to the east and west. The slip rate decreases westward along the central and western parts of the Denali fault system to 5 mm/yr over a length of ∼575 km. An additional site on the eastern Denali fault near Kluane Lake, Yukon, implies a slip rate of ∼2 mm/yr, based on geological considerations. The Totschunda fault has a maximum slip rate of ∼9 mm/yr. The Denali fault system is transpressional and there are active thrust faults on both the north and south sides of it. We explore four geometric models for southern Alaska tectonics to explain the slip rates along the Denali fault system and the active fault geometries: rotation, indentation, extrusion, and a combination of the three. We conclude that all three end-member models have strengths and shortcomings, and a combination of rotation, indentation, and extrusion best explains the slip rate observations.

Geometry and kinematics of the eastern Lake Mead fault system in the Virgin Mountains, Nevada and Arizona

USGS Publications Warehouse

Beard, Sue; Campagna, David J.; Anderson, R. Ernest

2010-01-01

The Lake Mead fault system is a northeast-striking, 130-km-long zone of left-slip in the southeast Great Basin, active from before 16 Ma to Quaternary time. The northeast end of the Lake Mead fault system in the Virgin Mountains of southeast Nevada and northwest Arizona forms a partitioned strain field comprising kinematically linked northeast-striking left-lateral faults, north-striking normal faults, and northwest-striking right-lateral faults. Major faults bound large structural blocks whose internal strain reflects their position within a left step-over of the left-lateral faults. Two north-striking large-displacement normal faults, the Lakeside Mine segment of the South Virgin–White Hills detachment fault and the Piedmont fault, intersect the left step-over from the southwest and northeast, respectively. The left step-over in the Lake Mead fault system therefore corresponds to a right-step in the regional normal fault system.Within the left step-over, displacement transfer between the left-lateral faults and linked normal faults occurs near their junctions, where the left-lateral faults become oblique and normal fault displacement decreases away from the junction. Southward from the center of the step-over in the Virgin Mountains, down-to-the-west normal faults splay northward from left-lateral faults, whereas north and east of the center, down-to-the-east normal faults splay southward from left-lateral faults. Minimum slip is thus in the central part of the left step-over, between east-directed slip to the north and west-directed slip to the south. Attenuation faults parallel or subparallel to bedding cut Lower Paleozoic rocks and are inferred to be early structures that accommodated footwall uplift during the initial stages of extension.Fault-slip data indicate oblique extensional strain within the left step-over in the South Virgin Mountains, manifested as east-west extension; shortening is partitioned between vertical for extension-dominated structural blocks and south-directed for strike-slip faults. Strike-slip faults are oblique to the extension direction due to structural inheritance from NE-striking fabrics in Proterozoic crystalline basement rocks.We hypothesize that (1) during early phases of deformation oblique extension was partitioned to form east-west–extended domains bounded by left-lateral faults of the Lake Mead fault system, from ca. 16 to 14 Ma. (2) Beginning ca. 13 Ma, increased south-directed shortening impinged on the Virgin Mountains and forced uplift, faulting, and overturning along the north and west side of the Virgin Mountains. (3) By ca. 10 Ma, initiation of the younger Hen Spring to Hamblin Bay fault segment of the Lake Mead fault system accommodated westward tectonic escape, and the focus of south-directed shortening transferred to the western Lake Mead region. The shift from early partitioned oblique extension to south-directed shortening may have resulted from initiation of right-lateral shear of the eastern Walker Lane to the west coupled with left-lateral shear along the eastern margin of the Great Basin.

Slip distribution, strain accumulation and aseismic slip on the Chaman Fault system

NASA Astrophysics Data System (ADS)

Amelug, F.

2015-12-01

The Chaman fault system is a transcurrent fault system developed due to the oblique convergence of the India and Eurasia plates in the western boundary of the India plate. To evaluate the contemporary rates of strain accumulation along and across the Chaman Fault system, we use 2003-2011 Envisat SAR imagery and InSAR time-series methods to obtain a ground velocity field in radar line-of-sight (LOS) direction. We correct the InSAR data for different sources of systematic biases including the phase unwrapping errors, local oscillator drift, topographic residuals and stratified tropospheric delay and evaluate the uncertainty due to the residual delay using time-series of MODIS observations of precipitable water vapor. The InSAR velocity field and modeling demonstrates the distribution of deformation across the Chaman fault system. In the central Chaman fault system, the InSAR velocity shows clear strain localization on the Chaman and Ghazaband faults and modeling suggests a total slip rate of ~24 mm/yr distributed on the two faults with rates of 8 and 16 mm/yr, respectively corresponding to the 80% of the total ~3 cm/yr plate motion between India and Eurasia at these latitudes and consistent with the kinematic models which have predicted a slip rate of ~17-24 mm/yr for the Chaman Fault. In the northern Chaman fault system (north of 30.5N), ~6 mm/yr of the relative plate motion is accommodated across Chaman fault. North of 30.5 N where the topographic expression of the Ghazaband fault vanishes, its slip does not transfer to the Chaman fault but rather distributes among different faults in the Kirthar range and Sulaiman lobe. Observed surface creep on the southern Chaman fault between Nushki and north of City of Chaman, indicates that the fault is partially locked, consistent with the recorded M<7 earthquakes in last century on this segment. The Chaman fault between north of the City of Chaman to North of Kabul, does not show an increase in the rate of strain accumulation. However, lack of seismicity on this segment, presents a significant hazard on Kabul. The high rate of strain accumulation on the Ghazaband fault and lack of evidence for the rupture of the fault during the 1935 Quetta earthquake, present a growing earthquake hazard to the Balochistan and the populated areas such as the city of Quetta.

The mid-Miocene structural conversion within the NE Tibetan Plateau from new proof of the interaction between two conflicting fault systems in the western Qaidam Basin

NASA Astrophysics Data System (ADS)

Zhao, H.; Wu, L.; Xiao, A.

2016-12-01

We present a detailed structural analysis on the fault geometry and Cenozoic development in the Dongping area, northwestern Qaidam Basin, based on the precise 3-D seismic interpretation, remote sensing images and seismic attribute analysis. Two conflicting fault systems distributed in different orientations ( EW-striking and NNW-striking) with opposing senses of shear are recognized and discussed, and the interaction between them provides new insights to the intracontinental deformation of the Qaidam Basin within the NE Tibetan Plateau. The EW-striking fault system constitutes the south part of the Altyn left-slip positive flower structure. Faulting on the EW-striking faults dominated the northwestern Qaidam since 40 Ma in respond to the inception of the Altyn Tagh fault system as a ductile shear zone, tilting the south slope of the Altyn Tagh. Whereas the NNW-striking fault system became the dominant structures since the mid-Miocene ( 15 Ma), induced by the large scale strike-slip of the Altyn Tagh fault which leads to the NE-SW directed compression of the Qaidam Basin. Thus it evidently implies a structural conversion taking place within the NE Tibetan Plateau since the mid-Miocece ( 15 Ma). Interestingly, the preexisting faults possibly restrained the development of the later period faults, while the latter tended to track and link to the former fault traces. Taken the large scale sinistral striking-slip East Kunlun fault system into account, the late Cenozoic intracontinental deformation in the Qaidam Basin showing the dextral transpressional attribute is suggested to be the consequence of the combined effect of its two border sinistral strike-slip faults, which furthermore favors a continuous and lateral-extrusion mechanism of the growth of the NE Tibetan Plateau.

Clustering of GPS velocities in the Mojave Block, southeastern California

NASA Astrophysics Data System (ADS)

Savage, J. C.; Simpson, R. W.

2013-04-01

find subdivisions within the Mojave Block using cluster analysis to identify groupings in the velocities observed at GPS stations there. The clusters are represented on a fault map by symbols located at the positions of the GPS stations, each symbol representing the cluster to which the velocity of that GPS station belongs. Fault systems that separate the clusters are readily identified on such a map. The most significant representation as judged by the gap test involves 4 clusters within the Mojave Block. The fault systems bounding the clusters from east to west are 1) the faults defining the eastern boundary of the Northeast Mojave Domain extended southward to connect to the Hector Mine rupture, 2) the Calico-Paradise fault system, 3) the Landers-Blackwater fault system, and 4) the Helendale-Lockhart fault system. This division of the Mojave Block is very similar to that proposed by Meade and Hager []. However, no cluster boundary coincides with the Garlock Fault, the northern boundary of the Mojave Block. Rather, the clusters appear to continue without interruption from the Mojave Block north into the southern Walker Lane Belt, similar to the continuity across the Garlock Fault of the shear zone along the Blackwater-Little Lake fault system observed by Peltzer et al. []. Mapped traces of individual faults in the Mojave Block terminate within the block and do not continue across the Garlock Fault [Dokka and Travis, ].

Timing of activity of two fault systems on Mercury

NASA Astrophysics Data System (ADS)

Galluzzi, V.; Guzzetta, L.; Giacomini, L.; Ferranti, L.; Massironi, M.; Palumbo, P.

2015-10-01

Here we discuss about two fault systems found in the Victoria and Shakespeare quadrangles of Mercury. The two fault sets intersect each other and show probable evidence for two stages of deformation. The most prominent system is N-S oriented and encompasses several tens to hundreds of kilometers long and easily recognizable fault segments. The other system strikes NE- SW and encompasses mostly degraded and short fault segments. The structural framework of the studied area and the morphological appearance of the faults suggest that the second system is older than the first one. We intend to apply the buffered crater counting technique on both systems to make a quantitative study of their timing of activity that could confirm the already clear morphological evidence.

Modeling and Fault Simulation of Propellant Filling System

NASA Astrophysics Data System (ADS)

Jiang, Yunchun; Liu, Weidong; Hou, Xiaobo

2012-05-01

Propellant filling system is one of the key ground plants in launching site of rocket that use liquid propellant. There is an urgent demand for ensuring and improving its reliability and safety, and there is no doubt that Failure Mode Effect Analysis (FMEA) is a good approach to meet it. Driven by the request to get more fault information for FMEA, and because of the high expense of propellant filling, in this paper, the working process of the propellant filling system in fault condition was studied by simulating based on AMESim. Firstly, based on analyzing its structure and function, the filling system was modular decomposed, and the mathematic models of every module were given, based on which the whole filling system was modeled in AMESim. Secondly, a general method of fault injecting into dynamic system was proposed, and as an example, two typical faults - leakage and blockage - were injected into the model of filling system, based on which one can get two fault models in AMESim. After that, fault simulation was processed and the dynamic characteristics of several key parameters were analyzed under fault conditions. The results show that the model can simulate effectively the two faults, and can be used to provide guidance for the filling system maintain and amelioration.

Structural superposition in fault systems bounding Santa Clara Valley, California

USGS Publications Warehouse

Graymer, Russell W.; Stanley, Richard G.; Ponce, David A.; Jachens, Robert C.; Simpson, Robert W.; Wentworth, Carl M.

2015-01-01

Santa Clara Valley is bounded on the southwest and northeast by active strike-slip and reverse-oblique faults of the San Andreas fault system. On both sides of the valley, these faults are superposed on older normal and/or right-lateral normal oblique faults. The older faults comprised early components of the San Andreas fault system as it formed in the wake of the northward passage of the Mendocino Triple Junction. On the east side of the valley, the great majority of fault displacement was accommodated by the older faults, which were almost entirely abandoned when the presently active faults became active after ca. 2.5 Ma. On the west side of the valley, the older faults were abandoned earlier, before ca. 8 Ma and probably accumulated only a small amount, if any, of the total right-lateral offset accommodated by the fault zone as a whole. Apparent contradictions in observations of fault offset and the relation of the gravity field to the distribution of dense rocks at the surface are explained by recognition of superposed structures in the Santa Clara Valley region.

Delivery and application of precise timing for a traveling wave powerline fault locator system

NASA Technical Reports Server (NTRS)

Street, Michael A.

1990-01-01

The Bonneville Power Administration (BPA) has successfully operated an in-house developed powerline fault locator system since 1986. The BPA fault locator system consists of remotes installed at cardinal power transmission line system nodes and a central master which polls the remotes for traveling wave time-of-arrival data. A power line fault produces a fast rise-time traveling wave which emanates from the fault point and propagates throughout the power grid. The remotes time-tag the traveling wave leading edge as it passes through the power system cardinal substation nodes. A synchronizing pulse transmitted via the BPA analog microwave system on a wideband channel sychronizes the time-tagging counters in the remote units to a different accuracy of better than one microsecond. The remote units correct the raw time tags for synchronizing pulse propagation delay and return these corrected values to the fault locator master. The master then calculates the power system disturbance source using the collected time tags. The system design objective is a fault location accuracy of 300 meters. BPA's fault locator system operation, error producing phenomena, and method of distributing precise timing are described.

Spatial and Temporal Variations in Slip Partitioning During Oblique Convergence Experiments

NASA Astrophysics Data System (ADS)

Beyer, J. L.; Cooke, M. L.; Toeneboehn, K.

2017-12-01

Physical experiments of oblique convergence in wet kaolin demonstrate the development of slip partitioning, where two faults accommodate strain via different slip vectors. In these experiments, the second fault forms after the development of the first fault. As one strain component is relieved by one fault, the local stress field then favors the development of a second fault with different slip sense. A suite of physical experiments reveals three styles of slip partitioning development controlled by the convergence angle and presence of a pre-existing fault. In experiments with low convergence angles, strike-slip faults grow prior to reverse faults (Type 1) regardless of whether the fault is precut or not. In experiments with moderate convergence angles, slip partitioning is dominantly controlled by the presence of a pre-existing fault. In all experiments, the primarily reverse fault forms first. Slip partitioning then develops with the initiation of strike-slip along the precut fault (Type 2) or growth of a secondary reverse fault where the first fault is steepest. Subsequently, the slip on the first fault transitions to primarily strike-slip (Type 3). Slip rates and rakes along the slip partitioned faults for both precut and uncut experiments vary temporally, suggesting that faults in these slip-partitioned systems are constantly adapting to the conditions produced by slip along nearby faults in the system. While physical experiments show the evolution of slip partitioning, numerical simulations of the experiments provide information about both the stress and strain fields, which can be used to compute the full work budget, providing insight into the mechanisms that drive slip partitioning. Preliminary simulations of precut experiments show that strain energy density (internal work) can be used to predict fault growth, highlighting where fault growth can reduce off-fault deformation in the physical experiments. In numerical simulations of uncut experiments with a first non-planar oblique slip fault, strain energy density is greatest where the first fault is steepest, as less convergence is accommodated along this portion of the fault. The addition of a second slip-partitioning fault to the system decreases external work indicating that these faults increase the mechanical efficiency of the system.

Late Quaternary faulting along the Death Valley-Furnace Creek fault system, California and Nevada

USGS Publications Warehouse

Brogan, George E.; Kellogg, Karl; Slemmons, D. Burton; Terhune, Christina L.

1991-01-01

The Death Valley-Furnace Creek fault system, in California and Nevada, has a variety of impressive late Quaternary neotectonic features that record a long history of recurrent earthquake-induced faulting. Although no neotectonic features of unequivocal historical age are known, paleoseismic features from multiple late Quaternary events of surface faulting are well developed throughout the length of the system. Comparison of scarp heights to amount of horizontal offset of stream channels and the relationships of both scarps and channels to the ages of different geomorphic surfaces demonstrate that Quaternary faulting along the northwest-trending Furnace Creek fault zone is predominantly right lateral, whereas that along the north-trending Death Valley fault zone is predominantly normal. These observations are compatible with tectonic models of Death Valley as a northwest-trending pull-apart basin. The largest late Quaternary scarps along the Furnace Creek fault zone, with vertical separation of late Pleistocene surfaces of as much as 64 m (meters), are in Fish Lake Valley. Despite the predominance of normal faulting along the Death Valley fault zone, vertical offset of late Pleistocene surfaces along the Death Valley fault zone apparently does not exceed about 15 m. Evidence for four to six separate late Holocene faulting events along the Furnace Creek fault zone and three or more late Holocene events along the Death Valley fault zone are indicated by rupturing of Q1B (about 200-2,000 years old) geomorphic surfaces. Probably the youngest neotectonic feature observed along the Death Valley-Furnace Creek fault system, possibly historic in age, is vegetation lineaments in southernmost Fish Lake Valley. Near-historic faulting in Death Valley, within several kilometers south of Furnace Creek Ranch, is represented by (1) a 2,000-year-old lake shoreline that is cut by sinuous scarps, and (2) a system of young scarps with free-faceted faces (representing several faulting events) that cuts Q1B surfaces.

Preparation of sodium fluoride-loaded gelatin microspheres, characterization and cariostatic studies.

PubMed

Wu, H; Zhang, Z X; Zhao, H P; Wu, D C; Wu, B L; Cong, R

2004-12-01

Sodium fluoride-loaded gelatin microspheres (NaF-GMS) were prepared using double-phase emulsified condensation polymerization. The average diameter of microspheres was (11.33+/-5.56) microm. The drug content and encapsulation efficiency were 8.80% and 76.73%, respectively. The fluoride releasing profiles of NaF-GMS in physiological saline and artificial saliva (pH 4.5, pH 6.8) showed that NaF-GMS had a sustained-release property and fluoride release rate was increased in pH 4.5 artificial saliva. Experiments conducted in rabbits' oral cavity using NaF-GMS and NaF solution as control revealed NaF-GMS could maintain oral fluoride retention longer than NaF solution. Cariostatic abilities of NaF-GMS including demineralization prohibition in vitro, fluoride deposition in artificial dental plaque and the ability of targeting to cariogenic bacteria were investigated in artificial dental plaque. The results indicated NaF-GMS with lower fluoride concentrations could achieve equivalent cariostatic effect to the concentrated NaF solution, at the same time, could prolong fluoride retention in dental plaque. Microscopic observation showed that NaF-GMS carrying fusion protein of glucan-binding domain could adhere more bacteria than NaF-GMS and this might indicate the possibility of targeting to cariogenic bacteria when NaF-GMS were properly modified.

Effect of Diode Laser Irradiation Combined with Topical Fluoride on Enamel Microhardness of Primary Teeth.

PubMed

Bahrololoomi, Zahra; Lotfian, Malihe

2015-02-01

Laser irradiation has been suggested as an adjunct to traditional caries prevention methods. But little is known about the cariostatic effect of diode laser and most studies available are on permanent teeth.The purpose of the present study was to investigate the effect of diode laser irradiation combined with topical fluoride on enamel surface microhardness. Forty-five primary teeth were used in this in vitro study. The teeth were sectioned to produce 90 slabs. The baseline Vickers microhardness number of each enamel surface was determined. The samples were randomly divided into 3 groups. Group 1: 5% NaF varnish, group 2: NaF varnish+ diode laser at 5 W power and group 3: NaF varnish+ diode laser at 7 W power. Then, the final microhardness number of each surface was again determined. The data were statistically analyzed by repeated measures ANOVA at 0.05 level of significance. In all 3 groups, microhardness number increased significantly after surface treatment (P<0.05). However, Microhardness change after treatment was not significantly different among groups (P >0.05). The combined application of diode laser and topical fluoride varnish on enamel surface did not show any significant additional effect on enamel resistance to caries.

Nitrate-Dependent Activation of the Dif Signaling Pathway of Myxococcus xanthus Mediated by a NarX-DifA Interspecies Chimera

PubMed Central

Xu, Qian; Black, Wesley P.; Ward, Scott M.; Yang, Zhaomin

2005-01-01

Myxococcus xanthus fibril exopolysaccharide (EPS), essential for the social gliding motility and development of this bacterium, is regulated by the Dif chemotaxis-like pathway. DifA, an MCP homolog, is proposed to mediate signal input to the Dif pathway. However, DifA lacks a prominent periplasmic domain, which in classical chemoreceptors is responsible for signal perception and for initiating transmembrane signaling. To investigate the signaling properties of DifA, we constructed a NarX-DifA (NafA) chimera from the sensory module of Escherichia coli NarX and the signaling module of M. xanthus DifA. We report here the first functional chimeric signal transducer constructed using genes from organisms in two different phylogenetic subdivisions. When expressed in M. xanthus, NafA restored fruiting body formation, EPS production, and S-motility to difA mutants in the presence of nitrate. Studies with various double mutants indicate that NafA requires the downstream Dif proteins to function. We propose that signal inputs to the Dif pathway and transmembrane signaling by DifA are essential for the regulation of EPS production in M. xanthus. Despite the apparent structural differences, DifA appears to share similar transmembrane signaling mechanisms with enteric sensor kinases and chemoreceptors. PMID:16159775

Influence of sodium fluoride (NaF) on the crystallization and spectral properties of L-tyrosine

NASA Astrophysics Data System (ADS)

Thenmozhi, M.; Suguna, K.; Sekar, C.

2011-12-01

L-Tyrosine (C 9H 11NO 3) is an essential amino acid in living organisms. It is also a building unit in protein, takes part in bio-synthesis of hormones, neurotransmitters, pigments and one of the organic chemical constituents of urinary stones. L-Tyrosine has been crystallized in silica gel by double diffusion technique with and without the addition of NaF. The crystals had rosette-like shape. In case of fluoride addition, two types of crystals have formed: rosette like crystallites, at the gel-solution interface and reticulate type crystallites beneath the interface. XRD results confirmed that both the products are of L-tyrosine with identical crystal structures. Crystal structure, morphology, thermal and spectral properties are analyzed using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric and differential thermal analysis (TG-DTA), Fourier transform infrared spectroscopy (FTIR) and UV-vis transmittance studies. The TG-DTA results suggest that the thermal stability of L-tyrosine has markedly improved due to fluoride doping. Optical band gap energy of NaF grown L-tyrosine crystallite is estimated as 4.28 eV. Second harmonic generation efficiency test indicates that L-tyrosine crystals can be used for application in nonlinear optical devices.

Simultaneous Event-Triggered Fault Detection and Estimation for Stochastic Systems Subject to Deception Attacks.

PubMed

Li, Yunji; Wu, QingE; Peng, Li

2018-01-23

In this paper, a synthesized design of fault-detection filter and fault estimator is considered for a class of discrete-time stochastic systems in the framework of event-triggered transmission scheme subject to unknown disturbances and deception attacks. A random variable obeying the Bernoulli distribution is employed to characterize the phenomena of the randomly occurring deception attacks. To achieve a fault-detection residual is only sensitive to faults while robust to disturbances, a coordinate transformation approach is exploited. This approach can transform the considered system into two subsystems and the unknown disturbances are removed from one of the subsystems. The gain of fault-detection filter is derived by minimizing an upper bound of filter error covariance. Meanwhile, system faults can be reconstructed by the remote fault estimator. An recursive approach is developed to obtain fault estimator gains as well as guarantee the fault estimator performance. Furthermore, the corresponding event-triggered sensor data transmission scheme is also presented for improving working-life of the wireless sensor node when measurement information are aperiodically transmitted. Finally, a scaled version of an industrial system consisting of local PC, remote estimator and wireless sensor node is used to experimentally evaluate the proposed theoretical results. In particular, a novel fault-alarming strategy is proposed so that the real-time capacity of fault-detection is guaranteed when the event condition is triggered.

Evaluation of an Enhanced Bank of Kalman Filters for In-Flight Aircraft Engine Sensor Fault Diagnostics

NASA Technical Reports Server (NTRS)

Kobayashi, Takahisa; Simon, Donald L.

2004-01-01

In this paper, an approach for in-flight fault detection and isolation (FDI) of aircraft engine sensors based on a bank of Kalman filters is developed. This approach utilizes multiple Kalman filters, each of which is designed based on a specific fault hypothesis. When the propulsion system experiences a fault, only one Kalman filter with the correct hypothesis is able to maintain the nominal estimation performance. Based on this knowledge, the isolation of faults is achieved. Since the propulsion system may experience component and actuator faults as well, a sensor FDI system must be robust in terms of avoiding misclassifications of any anomalies. The proposed approach utilizes a bank of (m+1) Kalman filters where m is the number of sensors being monitored. One Kalman filter is used for the detection of component and actuator faults while each of the other m filters detects a fault in a specific sensor. With this setup, the overall robustness of the sensor FDI system to anomalies is enhanced. Moreover, numerous component fault events can be accounted for by the FDI system. The sensor FDI system is applied to a commercial aircraft engine simulation, and its performance is evaluated at multiple power settings at a cruise operating point using various fault scenarios.

Faults Discovery By Using Mined Data

NASA Technical Reports Server (NTRS)

Lee, Charles

2005-01-01

Fault discovery in the complex systems consist of model based reasoning, fault tree analysis, rule based inference methods, and other approaches. Model based reasoning builds models for the systems either by mathematic formulations or by experiment model. Fault Tree Analysis shows the possible causes of a system malfunction by enumerating the suspect components and their respective failure modes that may have induced the problem. The rule based inference build the model based on the expert knowledge. Those models and methods have one thing in common; they have presumed some prior-conditions. Complex systems often use fault trees to analyze the faults. Fault diagnosis, when error occurs, is performed by engineers and analysts performing extensive examination of all data gathered during the mission. International Space Station (ISS) control center operates on the data feedback from the system and decisions are made based on threshold values by using fault trees. Since those decision-making tasks are safety critical and must be done promptly, the engineers who manually analyze the data are facing time challenge. To automate this process, this paper present an approach that uses decision trees to discover fault from data in real-time and capture the contents of fault trees as the initial state of the trees.

First Results from a Forward, 3-Dimensional Regional Model of a Transpressional San Andreas Fault System

NASA Astrophysics Data System (ADS)

Fitzenz, D. D.; Miller, S. A.

2001-12-01

We present preliminary results from a 3-dimensional fault interaction model, with the fault system specified by the geometry and tectonics of the San Andreas Fault (SAF) system. We use the forward model for earthquake generation on interacting faults of Fitzenz and Miller [2001] that incorporates the analytical solutions of Okada [85,92], GPS-constrained tectonic loading, creep compaction and frictional dilatancy [Sleep and Blanpied, 1994, Sleep, 1995], and undrained poro-elasticity. The model fault system is centered at the Big Bend, and includes three large strike-slip faults (each discretized into multiple subfaults); 1) a 300km, right-lateral segment of the SAF to the North, 2) a 200km-long left-lateral segment of the Garlock fault to the East, and 3) a 100km-long right-lateral segment of the SAF to the South. In the initial configuration, three shallow-dipping faults are also included that correspond to the thrust belt sub-parallel to the SAF. Tectonic loading is decomposed into basal shear drag parallel to the plate boundary with a 35mm yr-1 plate velocity, and East-West compression approximated by a vertical dislocation surface applied at the far-field boundary resulting in fault-normal compression rates in the model space about 4mm yr-1. Our aim is to study the long-term seismicity characteristics, tectonic evolution, and fault interaction of this system. We find that overpressured faults through creep compaction are a necessary consequence of the tectonic loading, specifically where high normal stress acts on long straight fault segments. The optimal orientation of thrust faults is a function of the strike-slip behavior, and therefore results in a complex stress state in the elastic body. This stress state is then used to generate new fault surfaces, and preliminary results of dynamically generated faults will also be presented. Our long-term aim is to target measurable properties in or around fault zones, (e.g. pore pressures, hydrofractures, seismicity catalogs, stress orientation, surface strain, triggering, etc.), which may allow inferences on the stress state of fault systems.

Abnormal fault-recovery characteristics of the fault-tolerant multiprocessor uncovered using a new fault-injection methodology

NASA Technical Reports Server (NTRS)

Padilla, Peter A.

1991-01-01

An investigation was made in AIRLAB of the fault handling performance of the Fault Tolerant MultiProcessor (FTMP). Fault handling errors detected during fault injection experiments were characterized. In these fault injection experiments, the FTMP disabled a working unit instead of the faulted unit once in every 500 faults, on the average. System design weaknesses allow active faults to exercise a part of the fault management software that handles Byzantine or lying faults. Byzantine faults behave such that the faulted unit points to a working unit as the source of errors. The design's problems involve: (1) the design and interface between the simplex error detection hardware and the error processing software, (2) the functional capabilities of the FTMP system bus, and (3) the communication requirements of a multiprocessor architecture. These weak areas in the FTMP's design increase the probability that, for any hardware fault, a good line replacement unit (LRU) is mistakenly disabled by the fault management software.

Implementation of a model based fault detection and diagnosis for actuation faults of the Space Shuttle main engine

NASA Technical Reports Server (NTRS)

Duyar, A.; Guo, T.-H.; Merrill, W.; Musgrave, J.

1992-01-01

In a previous study, Guo, Merrill and Duyar, 1990, reported a conceptual development of a fault detection and diagnosis system for actuation faults of the space shuttle main engine. This study, which is a continuation of the previous work, implements the developed fault detection and diagnosis scheme for the real time actuation fault diagnosis of the space shuttle main engine. The scheme will be used as an integral part of an intelligent control system demonstration experiment at NASA Lewis. The diagnosis system utilizes a model based method with real time identification and hypothesis testing for actuation, sensor, and performance degradation faults.

Robust Fault Detection and Isolation for Stochastic Systems

NASA Technical Reports Server (NTRS)

George, Jemin; Gregory, Irene M.

2010-01-01

This paper outlines the formulation of a robust fault detection and isolation scheme that can precisely detect and isolate simultaneous actuator and sensor faults for uncertain linear stochastic systems. The given robust fault detection scheme based on the discontinuous robust observer approach would be able to distinguish between model uncertainties and actuator failures and therefore eliminate the problem of false alarms. Since the proposed approach involves precise reconstruction of sensor faults, it can also be used for sensor fault identification and the reconstruction of true outputs from faulty sensor outputs. Simulation results presented here validate the effectiveness of the robust fault detection and isolation system.

Sliding Mode Observer-Based Current Sensor Fault Reconstruction and Unknown Load Disturbance Estimation for PMSM Driven System.

PubMed

Zhao, Kaihui; Li, Peng; Zhang, Changfan; Li, Xiangfei; He, Jing; Lin, Yuliang

2017-12-06

This paper proposes a new scheme of reconstructing current sensor faults and estimating unknown load disturbance for a permanent magnet synchronous motor (PMSM)-driven system. First, the original PMSM system is transformed into two subsystems; the first subsystem has unknown system load disturbances, which are unrelated to sensor faults, and the second subsystem has sensor faults, but is free from unknown load disturbances. Introducing a new state variable, the augmented subsystem that has sensor faults can be transformed into having actuator faults. Second, two sliding mode observers (SMOs) are designed: the unknown load disturbance is estimated by the first SMO in the subsystem, which has unknown load disturbance, and the sensor faults can be reconstructed using the second SMO in the augmented subsystem, which has sensor faults. The gains of the proposed SMOs and their stability analysis are developed via the solution of linear matrix inequality (LMI). Finally, the effectiveness of the proposed scheme was verified by simulations and experiments. The results demonstrate that the proposed scheme can reconstruct current sensor faults and estimate unknown load disturbance for the PMSM-driven system.

Kinematics of shallow backthrusts in the Seattle fault zone, Washington State

USGS Publications Warehouse

Pratt, Thomas L.; Troost, K.G.; Odum, Jackson K.; Stephenson, William J.

2015-01-01

Near-surface thrust fault splays and antithetic backthrusts at the tips of major thrust fault systems can distribute slip across multiple shallow fault strands, complicating earthquake hazard analyses based on studies of surface faulting. The shallow expression of the fault strands forming the Seattle fault zone of Washington State shows the structural relationships and interactions between such fault strands. Paleoseismic studies document an ∼7000 yr history of earthquakes on multiple faults within the Seattle fault zone, with some backthrusts inferred to rupture in small (M ∼5.5–6.0) earthquakes at times other than during earthquakes on the main thrust faults. We interpret seismic-reflection profiles to show three main thrust faults, one of which is a blind thrust fault directly beneath downtown Seattle, and four small backthrusts within the Seattle fault zone. We then model fault slip, constrained by shallow deformation, to show that the Seattle fault forms a fault propagation fold rather than the alternatively proposed roof thrust system. Fault slip modeling shows that back-thrust ruptures driven by moderate (M ∼6.5–6.7) earthquakes on the main thrust faults are consistent with the paleoseismic data. The results indicate that paleoseismic data from the back-thrust ruptures reveal the times of moderate earthquakes on the main fault system, rather than indicating smaller (M ∼5.5–6.0) earthquakes involving only the backthrusts. Estimates of cumulative shortening during known Seattle fault zone earthquakes support the inference that the Seattle fault has been the major seismic hazard in the northern Cascadia forearc in the late Holocene.

Development, Interaction and Linkage of Normal Fault Segments along the 100-km Bilila-Mtakataka Fault, Malawi

NASA Astrophysics Data System (ADS)

Fagereng, A.; Hodge, M.; Biggs, J.; Mdala, H. S.; Goda, K.

2016-12-01

Faults grow through the interaction and linkage of isolated fault segments. Continuous fault systems are those where segments interact, link and may slip synchronously, whereas non-continuous fault systems comprise isolated faults. As seismic moment is related to fault length (Wells and Coppersmith, 1994), understanding whether a fault system is continuous or not is critical in evaluating seismic hazard. Maturity may be a control on fault continuity: immature, low displacement faults are typically assumed to be non-continuous. Here, we study two overlapping, 20 km long, normal fault segments of the N-S striking Bilila-Mtakataka fault, Malawi, in the southern section of the East African Rift System. Despite its relative immaturity, previous studies concluded the Bilila-Mtakataka fault is continuous for its entire 100 km length, with the most recent event equating to an Mw8.0 earthquake (Jackson and Blenkinsop, 1997). We explore whether segment geometry and relationship to pre-existing high-grade metamorphic foliation has influenced segment interaction and fault development. Fault geometry and scarp height is constrained by DEMs derived from SRTM, Pleiades and `Structure from Motion' photogrammetry using a UAV, alongside direct field observations. The segment strikes differ on average by 10°, but up to 55° at their adjacent tips. The southern segment is sub-parallel to the foliation, whereas the northern segment is highly oblique to the foliation. Geometrical surface discontinuities suggest two isolated faults; however, displacement-length profiles and Coulomb stress change models suggest segment interaction, with potential for linkage at depth. Further work must be undertaken on other segments to assess the continuity of the entire fault, concluding whether an earthquake greater than that of the maximum instrumentally recorded (1910 M7.4 Rukwa) is possible.

Verification of an IGBT Fusing Switch for Over-current Protection of the SNS HVCM

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

Benwell, Andrew; Kemp, Mark; Burkhart, Craig

2010-06-11

An IGBT based over-current protection system has been developed to detect faults and limit the damage caused by faults in high voltage converter modulators. During normal operation, an IGBT enables energy to be transferred from storage capacitors to a H-bridge. When a fault occurs, the over-current protection system detects the fault, limits the fault current and opens the IGBT to isolate the remaining stored energy from the fault. This paper presents an experimental verification of the over-current protection system under applicable conditions.

Discrete Wavelet Transform for Fault Locations in Underground Distribution System

NASA Astrophysics Data System (ADS)

Apisit, C.; Ngaopitakkul, A.

2010-10-01

In this paper, a technique for detecting faults in underground distribution system is presented. Discrete Wavelet Transform (DWT) based on traveling wave is employed in order to detect the high frequency components and to identify fault locations in the underground distribution system. The first peak time obtained from the faulty bus is employed for calculating the distance of fault from sending end. The validity of the proposed technique is tested with various fault inception angles, fault locations and faulty phases. The result is found that the proposed technique provides satisfactory result and will be very useful in the development of power systems protection scheme.

Dynamic characteristics of a 20 kHz resonant power system - Fault identification and fault recovery

NASA Technical Reports Server (NTRS)

Wasynczuk, O.

1988-01-01

A detailed simulation of a dc inductor resonant driver and receiver is used to demonstrate the transient characteristics of a 20 kHz resonant power system during fault and overload conditions. The simulated system consists of a dc inductor resonant inverter (driver), a 50-meter transmission cable, and a dc inductor resonant receiver load. Of particular interest are the driver and receiver performance during fault and overload conditions and on the recovery characteristics following removal of the fault. The information gained from these studies sets the stage for further work in fault identification and autonomous power system control.

The Quaternary thrust system of the northern Alaska Range

USGS Publications Warehouse

Bemis, Sean P.; Carver, Gary A.; Koehler, Richard D.

2012-01-01

The framework of Quaternary faults in Alaska remains poorly constrained. Recent studies in the Alaska Range north of the Denali fault add significantly to the recognition of Quaternary deformation in this active orogen. Faults and folds active during the Quaternary occur over a length of ∼500 km along the northern flank of the Alaska Range, extending from Mount McKinley (Denali) eastward to the Tok River valley. These faults exist as a continuous system of active structures, but we divide the system into four regions based on east-west changes in structural style. At the western end, the Kantishna Hills have only two known faults but the highest rate of shallow crustal seismicity. The western northern foothills fold-thrust belt consists of a 50-km-wide zone of subparallel thrust and reverse faults. This broad zone of deformation narrows to the east in a transition zone where the range-bounding fault of the western northern foothills fold-thrust belt terminates and displacement occurs on thrust and/or reverse faults closer to the Denali fault. The eastern northern foothills fold-thrust belt is characterized by ∼40-km-long thrust fault segments separated across left-steps by NNE-trending left-lateral faults. Altogether, these faults accommodate much of the topographic growth of the northern flank of the Alaska Range.Recognition of this thrust fault system represents a significant concern in addition to the Denali fault for infrastructure adjacent to and transecting the Alaska Range. Although additional work is required to characterize these faults sufficiently for seismic hazard analysis, the regional extent and structural character should require the consideration of the northern Alaska Range thrust system in regional tectonic models.

Jurassic faults of southwest Alabama and offshore areas

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

Mink, R.M.; Tew, B.H.; Bearden, B.L.

1991-03-01

Four fault groups affecting Jurassic strata occur in the southwest and offshore Alabama areas. They include the regional basement rift trend, the regional peripheral fault trend, the Mobile graben fault system, and the Lower Mobile Bay fault system. The regional basement system rift and regional peripheral fault trends are distinct and rim the inner margin of the eastern Gulf Coastal Plain. The regional basement rift trend is genetically related to the breakup of Pangea and the opening of the Gulf of Mexico in the Late Triassic-Early Jurassic. This fault trend is thought to have formed contemporaneously with deposition of Latemore » Triassic-Early Jurassic Eagle Mills Formation and to displace pre-Mesozoic rocks. The regional peripheral fault trend consists of a group of en echelon extensional faults that are parallel or subparallel to regional strike of Gulf Coastal Plain strata and correspond to the approximate updip limit of thick Louann Salt. Nondiapiric salt features are associated with the trend and maximum structural development is exhibited in the Haynesville-Smackover section. No hydrocarbon accumulations have been documented in the pre-Jurassic strata of southwest and offshore Alabama. Productive hydrocarbon reservoirs occur in Jurassic strata along the trends of the fault groups, suggesting a significant relationship between structural development in the Jurassic and hydrocarbon accumulation. Hydrocarbon traps are generally structural or contain a major structural component and include salt anticlines, faulted salt anticlines, and extensional fault traps. All of the major hydrocarbon accumulations are associated with movement of the Louann Salt along the regional peripheral fault trend, the Mobile graben fault system, or the Lower Mobile Bay fault system.« less

The SCEC 3D Community Fault Model (CFM-v5): An updated and expanded fault set of oblique crustal deformation and complex fault interaction for southern California

NASA Astrophysics Data System (ADS)

Nicholson, C.; Plesch, A.; Sorlien, C. C.; Shaw, J. H.; Hauksson, E.

2014-12-01

Southern California represents an ideal natural laboratory to investigate oblique deformation in 3D owing to its comprehensive datasets, complex tectonic history, evolving components of oblique slip, and continued crustal rotations about horizontal and vertical axes. As the SCEC Community Fault Model (CFM) aims to accurately reflect this 3D deformation, we present the results of an extensive update to the model by using primarily detailed fault trace, seismic reflection, relocated hypocenter and focal mechanism nodal plane data to generate improved, more realistic digital 3D fault surfaces. The results document a wide variety of oblique strain accommodation, including various aspects of strain partitioning and fault-related folding, sets of both high-angle and low-angle faults that mutually interact, significant non-planar, multi-stranded faults with variable dip along strike and with depth, and active mid-crustal detachments. In places, closely-spaced fault strands or fault systems can remain surprisingly subparallel to seismogenic depths, while in other areas, major strike-slip to oblique-slip faults can merge, such as the S-dipping Arroyo Parida-Mission Ridge and Santa Ynez faults with the N-dipping North Channel-Pitas Point-Red Mountain fault system, or diverge with depth. Examples of the latter include the steep-to-west-dipping Laguna Salada-Indiviso faults with the steep-to-east-dipping Sierra Cucapah faults, and the steep southern San Andreas fault with the adjacent NE-dipping Mecca Hills-Hidden Springs fault system. In addition, overprinting by steep predominantly strike-slip faulting can segment which parts of intersecting inherited low-angle faults are reactivated, or result in mutual cross-cutting relationships. The updated CFM 3D fault surfaces thus help characterize a more complex pattern of fault interactions at depth between various fault sets and linked fault systems, and a more complex fault geometry than typically inferred or expected from projecting near-surface data down-dip, or modeled from surface strain and potential field data alone.

Mechanism of Action of TiF4 on Dental Enamel Surface: SEM/EDX, KOH-Soluble F, and X-Ray Diffraction Analysis.

PubMed

Comar, Lívia P; Souza, Beatriz M; Al-Ahj, Luana P; Martins, Jessica; Grizzo, Larissa T; Piasentim, Isabelle S; Rios, Daniela; Buzalaf, Marília Afonso Rabelo; Magalhães, Ana Carolina

2017-10-12

This in vitro study aimed to evaluate the action of TiF4 on sound and carious bovine and human enamel. Sound (S) and pre-demineralised (DE) bovine and human (primary and permanent) enamel samples were treated with TiF4 (pH 1.0) or NaF varnishes (pH 5.0), containing 0.95, 1.95, or 2.45% F for 12 h. The enamel surfaces were analysed using SEM-EDX (scanning electron microscopy/energy-dispersive X-ray spectroscopy) (n = 10, 5 S and 5 DE) and KOH-soluble fluoride was quantified (n = 20, 10 S and 10 DE). Hydroxyapatite powder produced by precipitation method was treated with the corresponding fluoride solutions for 1 min (n = 2). The formed compounds were detected using X-ray diffraction (XRD). All TiF4 varnishes produced a coating layer rich in Ti and F on all types of enamel surface, with micro-cracks in its extension. TiF4 (1.95 and 2.45% F) provided higher fluoride deposition than NaF, especially for bovine enamel (p < 0.0001). It also induced a higher fluoride deposition on DE samples compared to S samples (p < 0.0001), except for primary enamel. The Ti content was higher for bovine and human primary enamel than human permanent enamel, with some differences between S and DE. The XRD analysis showed that TiF4 induced the formation of new compounds such as CaF2, TiO2, and Ti(HPO4)2·H2O. In conclusion, TiF4 (>0.95% F) interacts better, when compared to NaF, with bovine and human primary enamel than with human permanent enamel. TiF4 provoked higher F deposition compared to NaF. Carious enamel showed higher F uptake than sound enamel by TiF4 application, while Ti uptake was dependent on the enamel condition and origin. © 2017 S. Karger AG, Basel.

Trends and sources vs air mass origins in a major city in South-western Europe: Implications for air quality management.

PubMed

Fernández-Camacho, R; de la Rosa, J D; Sánchez de la Campa, A M

2016-05-15

This study presents a 17-years air quality database comprised of different parameters corresponding to the largest city in the south of Spain (Seville) where atmospheric pollution is frequently attributed to traffic emissions and is directly affected by Saharan dust outbreaks. We identify the PM10 contributions from both natural and anthropogenic sources in this area associated to different air mass origins. Hourly, daily and seasonal variation of PM10 and gaseous pollutant concentrations (CO, NO2 and SO2), all of them showing negative trends during the study period, point to the traffic as one of the main sources of air pollution in Seville. Mineral dust, secondary inorganic compounds (SIC) and trace elements showed higher concentrations under North African (NAF) air mass origins than under Atlantic. We observe a decreasing trend in all chemical components of PM10 under both types of air masses, NAF and Atlantic. Principal component analysis using more frequent air masses in the area allows the identification of five PM10 sources: crustal, regional, marine, traffic and industrial. Natural sources play a more relevant role during NAF events (20.6 μg · m(-3)) than in Atlantic episodes (13.8 μg · m(-3)). The contribution of the anthropogenic sources under NAF doubles the one under Atlantic conditions (33.6 μg · m(-3) and 15.8 μg · m(-3), respectively). During Saharan dust outbreaks the frequent accumulation of local anthropogenic pollutants in the lower atmosphere results in poor air quality and an increased risk of mortality. The results are relevant when analysing the impact of anthropogenic emissions on the exposed population in large cities. The increase in potentially toxic elements during Saharan dust outbreaks should also be taken into account when discounting the number of exceedances attributable to non-anthropogenic or natural origins. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of Silver Nitrate and Sodium Fluoride with Tri-Calcium Phosphate on Streptococcus mutans and Demineralised Dentine.

PubMed

Yu, Ollie Yiru; Zhao, Irene Shuping; Mei, May Lei; Lo, Edward Chin-Man; Chu, Chun-Hung

2018-04-25

This study investigated the effect of 25% silver nitrate (AgNO₃) and 5% sodium fluoride (NaF) varnish with functionalized tri-calcium phosphate (fTCP) on a Streptococcus mutans ( S. mutans ) biofilm and dentine caries lesion. Demineralised dentine specimens were treated with 25% AgNO₃ and 5% NaF + fTCP (Group 1), 25% AgNO₃ and 5% NaF (Group 2), 25% AgNO₃ (Group 3), or water (Group 4). The specimens were subjected to a S. mutans biofilm challenge after treatment. The biofilm was then studied via scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and colony forming units (CFU). The specimens were assessed by micro-computed tomography, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). SEM and CLSM revealed less biofilm in Groups 1 to 3. The log 10 CFU of Groups 1 to 4 were 4.5 ± 0.7, 4.4 ± 0.9, 4.4 ± 0.9, and 6.7 ± 1.0, respectively (Groups 1, 2, 3 < 4, p < 0.001). The lesion depths of Groups 1 to 4 were 212.6 ± 20.1 µm, 280.8 ± 51.6 µm, 402.5 ± 61.7 µm, and 497.4 ± 67.2 µm, respectively (Groups 1 < 2 < 3 < 4, p < 0.001). XRD demonstrated silver chloride formation in Groups 1, 2, and 3. FTIR found the amide I: HPO₄ 2− values of the four groups were 0.22 ± 0.05, 0.25 ± 0.05, 0.41 ± 0.12, and 0.64 ± 0.14, respectively (Groups 1, 2 < 3 < 4; p < 0.001). In conclusion, this study revealed that AgNO₃ and NaF + fTCP reduced the damage of dentine caries by cariogenic biofilm.

Impact of Nano Hydroxyapatite, Nano Silver Fluoride and Sodium Fluoride Varnish on Primary Teeth Enamel Remineralization: An In Vitro Study

PubMed Central

Nozari, Ali; Ajami, Shabnam; Rafiei, Azade

2017-01-01

Introduction Dental caries is still prevailing worldwide, although different anti caries products have been introduced. Each remineralizing agent has its own shortcomings. Therefore, looking for new agents to have benefits of previous ones with lesser side effects is worthwhile. Aim To determine the remineralization ability of NaF varnish, nano-Hydroxyapatite Serum (n-HAP) and Nano Silver Fluoride (NSF) on enamel of primary anterior teeth. Materials and Methods Incipient caries were induced in primary sound anterior teeth by storing each specimen in demineralization solution for 72 hours. Then they were randomly divided into four groups of 15 samples each: (1) NaF varnish; (2) n-HAP repairing serum; (3) NSF and (4) no treatment (control). Surface Microhardness (SMH) was assessed with Vickers micro hardness tester before and after demineralization and after 10 days of pH-cycling. A total of 12 random specimens from groups 1 to 4 (3 random samples of each group) were examined by Atomic Force Microscopy (AFM). The SMH values were analysed with one-way and repeated measures ANOVA. Level of significance was set at p=0.05. Results Post lesion SMH values significantly decreased in all groups (p<0.001). Post treatment SMH values significantly increased in comparison to post lesion ones (p<0.001) except for control group which was not different statistically (p=0.86). The highest SMH values were observed in NSF group (mean 222.90 ± 28.79). Statistically significant differences were shown between all groups (p<0.05). However, NaF varnish and n-HAP groups were not statistically different (p=0.165). AFM images demonstrated protective layers in all treated groups. Conclusion The results of this in vitro study suggest that NSF could have the greatest remineralization efficacy. NaF varnish and n-HAP serum were similar in remineralizing initial caries. Future clinical studies are recommended for selection of the most appropriate remineralizing agent in primary teeth. PMID:29207844

TiF4 varnish protects the retention of brackets to enamel after in vitro mild erosive challenge.

PubMed

Medeiros, Maria Isabel Dantas de; Carlo, Hugo Lemes; Santos, Rogério Lacerda Dos; Sousa, Frederico Barbosa; Castro, Ricardo Dias de; França, Renata Cristina Sobreira; Carvalho, Fabíola Galbiatti de

2018-05-14

The effect of fluoride agents on the retention of orthodontic brackets to enamel under erosive challenge is little investigated. The aim of this study was to evaluate the effect of titanium tetrafluoride (TiF4) and sodium fluoride (NaF) agents on the shear bond strength of brackets to enamel and on the enamel microhardness around brackets under erosive challenge. Brackets were bonded to bovine incisors. Five groups were formed according to fluoride application (n=10): TiF4 varnish, TiF4 solution, NaF varnish, NaF solution and control (without application). The specimens were submitted to erosive challenge (90 s cola drink/2h artificial saliva, 4x per day for 7 days). Solutions were applied before each erosive cycle and varnishes were applied once. Vickers Microhardness (VHN) was obtained before and after all cycles of erosion and the percentage of microhardness loss was calculated. Shear bond strength, adhesive remnant index and polarized light microscopy were conducted after erosion. The data were analyzed by ANOVA, Tukey, Kruskal-Wallis and Mann-Whitney U tests (α=0.05). The %VHN had no statistically significant differences among the experimental groups. However, considering the comparisons of all groups with the control group, TiF4 varnish showed the highest protection from enamel demineralization (effect size of 2.94, while the effect size for the other groups was >2.4). The TiF4 varnish group had significantly higher shear bond strength compared to other groups. There was no difference among groups for adhesive remnant index. Polarized light microscopy showed higher demineralization depth for the control group. Application of NaF and TiF4 agents during mild erosive challenge minimized the enamel mineral loss around brackets, however only the experimental TiF4 varnish was able to prevent the reduction of shear bond strength of brackets to enamel.

Fluoride Varnishes against Dental Erosion Caused by Soft Drink Combined with Pediatric Liquid Medicine.

PubMed

Alexandria, Adílis Kalina; Valença, Ana Maria Gondim; Cabral, Lúcio Mendes; Maia, Lucianne Cople

2017-01-01

The present study evaluated the effect of NaF and CPP-ACP/NaF varnishes to reduce erosion produced by soft drink (SD) combined or not with pediatric liquid medicine. Enamel specimens were pre-treated with fluoride varnish, according to the following groups: NaF varnish (Duraphat®) or CPP-ACP/NaF varnish (MI varnishTM). Two types of erosive cycles were made: by soft drink erosion (SDE) or by pediatric liquid medicine plus soft drink erosion (PLM/SDE). Bovine enamel specimens were randomly assigned in six groups (n=10): G1=NaF + SDE; G2=CPP-ACP/NaF + SDE; G3=Distilled and deionized (DD) water + SDE; G4=NaF + PLM/SDE; G5=CPP-ACP/NaF + PLM/SDE and G6=DD water + PLM/SDE. Before treatments, the sample surface was divided in two areas (unexposed area-UA and exposed area-EA). The specimens were evaluated by 3D non-contact profilometry technique to determinate tooth structure loss (TSL) and surface roughness (Sa). Scanning electron microscopy (SEM) analysis was also performed. After SDE, G2 presented the lowest TSL values compared to G3 (p=0.008). G1 and G2 did not differ between them (p=0.203) and no groups differed among them despite Sa. Regarding TSL and Sa, G4 and G5 differed from G6 (p=0.0001), but not between them (p=1.00). Examining 3D and SEM images, the greatest differences between UA and EA were observed for G3 and G6. CPP-ACP/NaF varnish seems to be a promising treatment to reduce enamel loss from the erosion produced by a soft drink. Both varnishes also showed capacity to reduce TSL and Sa after erosion by soft drink combined to pediatric liquid medicine.

IMPACT OF FLUORIDE ON DENTAL HEALTH QUALITY.

PubMed

Medjedovic, Eida; Medjedovic, Senad; Deljo, Dervis; Sukalo, Aziz

2015-12-01

Fluoride is natural element that strengthens teeth and prevents their decay. Experts believe that the best way to prevent cavities is the use of fluoride from multiple sources. Studies even show that in some cases, fluoride can stop already started damage of the teeth. In children younger than 6 years fluoride is incorporated into the enamel of permanent teeth, making the teeth more resistant to the action of bacterial and acids in food. The aim of this study is to determine the effects of improving the health status of teeth after six months treatment with the use of topical fluoridation 0.5% NaF, and the level and quality of the impact of treatment with chemical 0.5% NaF on the dental health of children at age from 8 to 15 years, in relation to gender and chronological age. This study included school children aged 8 to 15 years who visited health and dental services dependent in Mostar. It is obvious that after the implementation of treatment with 5% NaF by the method of topical fluoridation, health status of subjects from the experimental group significantly improved, so that at the final review 89.71% or 61 subjects of the experimental group had healthy (cured teeth), tooth with dental caries only 5.88% or 4 respondents tooth with dental caries and filling 4.41% or 3 respondents, extracted baby tooth 14.71% or 10 respondents, while for 13.24% of respondents was identified state with still unerupted teeth. Our findings are indirectly confirmed that the six-month treatment of fluoridation with 5% NaF, contributed to statistically significant improvement in overall oral health of the experimental group compared to the control group which was not treated by any dental treatment. It can be concluded that there is a statistically significant difference in the evaluated parameters of oral health of children in the control group compared to the studied parameters of oral health the experimental group of children at the final dental examination.

Effectiveness of a mouthrinse containing active ingredients in addition to chlorhexidine and triclosan compared with chlorhexidine and triclosan rinses on plaque, gingivitis, supragingival calculus and extrinsic staining.

PubMed

Kumar, S; Patel, S; Tadakamadla, J; Tibdewal, H; Duraiswamy, P; Kulkarni, S

2013-02-01

To assess the effectiveness of three different mouthrinses--chlorhexidine, triclosan + sodium fluoride and chlorhexidine + triclosan + sodium fluoride + zinc chloride--on plaque, calculus, gingivitis and stains and to evaluate the occurrence of adverse effects with these three treatments. Forty-eight healthy subjects participated in a double-blind, randomized, parallel experiment and were randomly allocated to any one of the three experimental mouthrinses: group A (0.2% chlorhexidine (CHX) gluconate), group B (0.03% triclosan + 0.025% sodium fluoride (NaF) + 12% ethyl alcohol) or group C (0.2% CHX + 0.3% triclosan + 0.3% NaF + 0.09% Zn chloride (ZnCl(2)). All the subjects were assessed for gingivitis, plaque, supragingival calculus and extrinsic stains at baseline and at the end of the 21-day experimental period. There was a significant difference (P = 0.046) in the effectiveness for the prevention of gingivitis and plaque, with subjects of group A and group C presenting least and highest gingival and plaque scores, respectively. Significant differences (P = 0.03) were observed for the accumulation of supragingival calculus where the deposition of calculus in group A was nearly double that of the group B, and group B was most effective in the prevention of supragingival calculus. Highest deposition of extrinsic stains was in the group A followed by group C and group B. There was no significant difference between the three treatments for adverse events' occurrence. CHX mouthrinse was most effective in controlling plaque and gingivitis but caused greatest deposition of extrinsic stains. Supragingival calculus deposition was least in triclosan + NaF group followed by CHX + triclosan + NaF + ZnCl(2) and CHX. More than half of the subjects reported adverse events during the experimental phase. © 2012 John Wiley & Sons A/S.

Transscleral diffusion of ethacrynic acid and sodium fluorescein

PubMed Central

Lin, Cheng-Wen; Wang, Yong; Challa, Pratap; Epstein, David L.

2007-01-01

Purpose One of the current limitations in developing novel glaucoma drugs that target the trabecular meshwork (TM) is the induced corneal toxicity from eyedrop formulations. To avoid the corneal toxicity, an alternative approach would be to deliver TM drugs through the sclera. To this end, we quantified ex vivo diffusion coefficient of a potential TM drug, ethacrynic acid (ECA), and investigated mechanisms of ECA transport in the sclera. Methods An Ussing-type diffusion apparatus was built to measure the apparent diffusion coefficient of ECA in fresh porcine sclera at 4 °C. To understand mechanisms of ECA transport, we quantified the transscleral transport of a fluorescent tracer, sodium fluorescein (NaF), that has a similar molecular weight but is more hydrophilic compared to ECA. Furthermore, we developed a mathematical model to simulate the transport processes and used it to analyze the experimental data. The model was also used to investigate the dependence of diffusion coefficients on volume fraction of viable cells and the binding of NaF and ECA to scleral tissues. Results The diffusion coefficients of ECA and NaF in the sclera were 48.5±15.1x10-7 cm2/s (n=9) and 5.23±1.93x10-7 cm2/s (n=8), respectively. Both diffusion coefficients were insensitive to cell shrinkage caused by ECA during the diffusion experiments and cell damage caused by the storage of tissues ex vivo before the experiments. Binding of ECA to scleral tissues could not be detected. The apparent maximum binding capacity and the apparent equilibrium dissociation constant for NaF were 80±5 mM and 2.5±0.5 mM (n=3), respectively. Conclusions These data demonstrated that ECA diffusion was minimally hindered by structures in the sclera, presumably due to the lack of cells and binding sites for ECA in the sclera. PMID:17356511

Structural controls on a geothermal system in the Tarutung Basin, north central Sumatra

NASA Astrophysics Data System (ADS)

Nukman, Mochamad; Moeck, Inga

2013-09-01

The Sumatra Fault System provides a unique geologic setting to evaluate the influence of structural controls on geothermal activity. Whereas most of the geothermal systems in Indonesia are controlled by volcanic activity, geothermal systems at the Sumatra Fault System might be controlled by faults and fractures. Exploration strategies for these geothermal systems need to be verified because the typical pattern of heat source and alteration clays are missing so that conventional exploration with magnetotelluric surveys might not provide sufficient data to delineate favorable settings for drilling. We present field geological, structural and geomorphological evidence combined with mapping of geothermal manifestations to allow constraints between fault dynamics and geothermal activity in the Tarutung Basin in north central Sumatra. Our results indicate that the fault pattern in the Tarutung Basin is generated by a compressional stress direction acting at a high angle to the right-lateral Sumatra Fault System. NW-SE striking normal faults possibly related to negative flower structures and NNW-SSE to NNE-SSW oriented dilative Riedel shears are preferential fluid pathways whereas ENE-WSW striking faults act as barriers in this system. The dominant of geothermal manifestations at the eastern part of the basin indicates local extension due to clockwise block rotation in the Sumatra Fault System. Our results support the effort to integrate detailed field geological surveys to refined exploration strategies even in tropical areas where outcrops are limited.

The Trans-Rocky Mountain Fault System - A Fundamental Precambrian Strike-Slip System

USGS Publications Warehouse

Sims, P.K.

2009-01-01

Recognition of a major Precambrian continental-scale, two-stage conjugate strike-slip fault system - here designated as the Trans-Rocky Mountain fault system - provides new insights into the architecture of the North American continent. The fault system consists chiefly of steep linear to curvilinear, en echelon, braided and branching ductile-brittle shears and faults, and local coeval en echelon folds of northwest strike, that cut indiscriminately across both Proterozoic and Archean cratonic elements. The fault system formed during late stages of two distinct tectonic episodes: Neoarchean and Paleoproterozoic orogenies at about 2.70 and 1.70 billion years (Ga). In the Archean Superior province, the fault system formed (about 2.70-2.65 Ga) during a late stage of the main deformation that involved oblique shortening (dextral transpression) across the region and progressed from crystal-plastic to ductile-brittle deformation. In Paleoproterozoic terranes, the fault system formed about 1.70 Ga, shortly following amalgamation of Paleoproterozoic and Archean terranes and the main Paleoproterozoic plastic-fabric-producing events in the protocontinent, chiefly during sinistral transpression. The postulated driving force for the fault system is subcontinental mantle deformation, the bottom-driven deformation of previous investigators. This model, based on seismic anisotropy, invokes mechanical coupling and subsequent shear between the lithosphere and the asthenosphere such that a major driving force for plate motion is deep-mantle flow.

Automatic Fault Characterization via Abnormality-Enhanced Classification

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

Bronevetsky, G; Laguna, I; de Supinski, B R

Enterprise and high-performance computing systems are growing extremely large and complex, employing hundreds to hundreds of thousands of processors and software/hardware stacks built by many people across many organizations. As the growing scale of these machines increases the frequency of faults, system complexity makes these faults difficult to detect and to diagnose. Current system management techniques, which focus primarily on efficient data access and query mechanisms, require system administrators to examine the behavior of various system services manually. Growing system complexity is making this manual process unmanageable: administrators require more effective management tools that can detect faults and help tomore » identify their root causes. System administrators need timely notification when a fault is manifested that includes the type of fault, the time period in which it occurred and the processor on which it originated. Statistical modeling approaches can accurately characterize system behavior. However, the complex effects of system faults make these tools difficult to apply effectively. This paper investigates the application of classification and clustering algorithms to fault detection and characterization. We show experimentally that naively applying these methods achieves poor accuracy. Further, we design novel techniques that combine classification algorithms with information on the abnormality of application behavior to improve detection and characterization accuracy. Our experiments demonstrate that these techniques can detect and characterize faults with 65% accuracy, compared to just 5% accuracy for naive approaches.« less

Sequential Test Strategies for Multiple Fault Isolation

NASA Technical Reports Server (NTRS)

Shakeri, M.; Pattipati, Krishna R.; Raghavan, V.; Patterson-Hine, Ann; Kell, T.

1997-01-01

In this paper, we consider the problem of constructing near optimal test sequencing algorithms for diagnosing multiple faults in redundant (fault-tolerant) systems. The computational complexity of solving the optimal multiple-fault isolation problem is super-exponential, that is, it is much more difficult than the single-fault isolation problem, which, by itself, is NP-hard. By employing concepts from information theory and Lagrangian relaxation, we present several static and dynamic (on-line or interactive) test sequencing algorithms for the multiple fault isolation problem that provide a trade-off between the degree of suboptimality and computational complexity. Furthermore, we present novel diagnostic strategies that generate a static diagnostic directed graph (digraph), instead of a static diagnostic tree, for multiple fault diagnosis. Using this approach, the storage complexity of the overall diagnostic strategy reduces substantially. Computational results based on real-world systems indicate that the size of a static multiple fault strategy is strictly related to the structure of the system, and that the use of an on-line multiple fault strategy can diagnose faults in systems with as many as 10,000 failure sources.

Fault Modeling of Extreme Scale Applications Using Machine Learning

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

Vishnu, Abhinav; Dam, Hubertus van; Tallent, Nathan R.

Faults are commonplace in large scale systems. These systems experience a variety of faults such as transient, permanent and intermittent. Multi-bit faults are typically not corrected by the hardware resulting in an error. Here, this paper attempts to answer an important question: Given a multi-bit fault in main memory, will it result in an application error — and hence a recovery algorithm should be invoked — or can it be safely ignored? We propose an application fault modeling methodology to answer this question. Given a fault signature (a set of attributes comprising of system and application state), we use machinemore » learning to create a model which predicts whether a multibit permanent/transient main memory fault will likely result in error. We present the design elements such as the fault injection methodology for covering important data structures, the application and system attributes which should be used for learning the model, the supervised learning algorithms (and potentially ensembles), and important metrics. Lastly, we use three applications — NWChem, LULESH and SVM — as examples for demonstrating the effectiveness of the proposed fault modeling methodology.« less

Fault Modeling of Extreme Scale Applications Using Machine Learning

DOE PAGES

Vishnu, Abhinav; Dam, Hubertus van; Tallent, Nathan R.; ...

2016-05-01

Faults are commonplace in large scale systems. These systems experience a variety of faults such as transient, permanent and intermittent. Multi-bit faults are typically not corrected by the hardware resulting in an error. Here, this paper attempts to answer an important question: Given a multi-bit fault in main memory, will it result in an application error — and hence a recovery algorithm should be invoked — or can it be safely ignored? We propose an application fault modeling methodology to answer this question. Given a fault signature (a set of attributes comprising of system and application state), we use machinemore » learning to create a model which predicts whether a multibit permanent/transient main memory fault will likely result in error. We present the design elements such as the fault injection methodology for covering important data structures, the application and system attributes which should be used for learning the model, the supervised learning algorithms (and potentially ensembles), and important metrics. Lastly, we use three applications — NWChem, LULESH and SVM — as examples for demonstrating the effectiveness of the proposed fault modeling methodology.« less

A comparative study of sensor fault diagnosis methods based on observer for ECAS system

NASA Astrophysics Data System (ADS)

Xu, Xing; Wang, Wei; Zou, Nannan; Chen, Long; Cui, Xiaoli

2017-03-01

The performance and practicality of electronically controlled air suspension (ECAS) system are highly dependent on the state information supplied by kinds of sensors, but faults of sensors occur frequently. Based on a non-linearized 3-DOF 1/4 vehicle model, different methods of fault detection and isolation (FDI) are used to diagnose the sensor faults for ECAS system. The considered approaches include an extended Kalman filter (EKF) with concise algorithm, a strong tracking filter (STF) with robust tracking ability, and the cubature Kalman filter (CKF) with numerical precision. We propose three filters of EKF, STF, and CKF to design a state observer of ECAS system under typical sensor faults and noise. Results show that three approaches can successfully detect and isolate faults respectively despite of the existence of environmental noise, FDI time delay and fault sensitivity of different algorithms are different, meanwhile, compared with EKF and STF, CKF method has best performing FDI of sensor faults for ECAS system.

Hardware fault insertion and instrumentation system: Mechanization and validation

NASA Technical Reports Server (NTRS)

Benson, J. W.

1987-01-01

Automated test capability for extensive low-level hardware fault insertion testing is developed. The test capability is used to calibrate fault detection coverage and associated latency times as relevant to projecting overall system reliability. Described are modifications made to the NASA Ames Reconfigurable Flight Control System (RDFCS) Facility to fully automate the total test loop involving the Draper Laboratories' Fault Injector Unit. The automated capability provided included the application of sequences of simulated low-level hardware faults, the precise measurement of fault latency times, the identification of fault symptoms, and bulk storage of test case results. A PDP-11/60 served as a test coordinator, and a PDP-11/04 as an instrumentation device. The fault injector was controlled by applications test software in the PDP-11/60, rather than by manual commands from a terminal keyboard. The time base was especially developed for this application to use a variety of signal sources in the system simulator.

The weakest t-norm based intuitionistic fuzzy fault-tree analysis to evaluate system reliability.

PubMed

Kumar, Mohit; Yadav, Shiv Prasad

2012-07-01

In this paper, a new approach of intuitionistic fuzzy fault-tree analysis is proposed to evaluate system reliability and to find the most critical system component that affects the system reliability. Here weakest t-norm based intuitionistic fuzzy fault tree analysis is presented to calculate fault interval of system components from integrating expert's knowledge and experience in terms of providing the possibility of failure of bottom events. It applies fault-tree analysis, α-cut of intuitionistic fuzzy set and T(ω) (the weakest t-norm) based arithmetic operations on triangular intuitionistic fuzzy sets to obtain fault interval and reliability interval of the system. This paper also modifies Tanaka et al.'s fuzzy fault-tree definition. In numerical verification, a malfunction of weapon system "automatic gun" is presented as a numerical example. The result of the proposed method is compared with the listing approaches of reliability analysis methods. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

Comparisons of stuttering frequency during and after speech initiation in unaltered feedback, altered auditory feedback and choral speech conditions.

PubMed

Saltuklaroglu, Tim; Kalinowski, Joseph; Robbins, Mary; Crawcour, Stephen; Bowers, Andrew

2009-01-01

Stuttering is prone to strike during speech initiation more so than at any other point in an utterance. The use of auditory feedback (AAF) has been found to produce robust decreases in the stuttering frequency by creating an electronic rendition of choral speech (i.e., speaking in unison). However, AAF requires users to self-initiate speech before it can go into effect and, therefore, it might not be as helpful as true choral speech during speech initiation. To examine how AAF and choral speech differentially enhance fluency during speech initiation and in subsequent portions of utterances. Ten participants who stuttered read passages without altered feedback (NAF), under four AAF conditions and under a true choral speech condition. Each condition was blocked into ten 10 s trials separated by 5 s intervals so each trial required 'cold' speech initiation. In the first analysis, comparisons of stuttering frequencies were made across conditions. A second, finer grain analysis involved examining stuttering frequencies on the initial syllable, the subsequent four syllables produced and the five syllables produced immediately after the midpoint of each trial. On average, AAF reduced stuttering by approximately 68% relative to the NAF condition. Stuttering frequencies on the initial syllables were considerably higher than on the other syllables analysed (0.45 and 0.34 for NAF and AAF conditions, respectively). After the first syllable was produced, stuttering frequencies dropped precipitously and remained stable. However, this drop in stuttering frequency was significantly greater (approximately 84%) in the AAF conditions than in the NAF condition (approximately 66%) with frequencies on the last nine syllables analysed averaging 0.15 and 0.05 for NAF and AAF conditions, respectively. In the true choral speech condition, stuttering was virtually (approximately 98%) eliminated across all utterances and all syllable positions. Altered auditory feedback effectively inhibits stuttering immediately after speech has been initiated. However, unlike a true choral signal, which is exogenously initiated and offers the most complete fluency enhancement, AAF requires speech to be initiated by the user and 'fed back' before it can directly inhibit stuttering. It is suggested that AAF can be a viable clinical option for those who stutter and should often be used in combination with therapeutic techniques, particularly those that aid speech initiation. The substantially higher rate of stuttering occurring on initiation supports a hypothesis that overt stuttering events help 'release' and 'inhibit' central stuttering blocks. This perspective is examined in the context of internal models and mirror neurons.

GPS Measurements for Detecting Aseismic Creeping in the Ismetpasa Region of North Anatolian Fault Zone, Turkey

NASA Astrophysics Data System (ADS)

Ozener, H.; Dogru, A.; Turgut, B.; Yilmaz, O.; Halicioglu, K.; Sabuncu, A.

2010-12-01

In 1972, a six point-network was established by General Directorate of Mapping in Gerede-Ismetpasa. This region is relatively quiet segment of western NAF which is creeping along steadily. This network was surveyed by terrestrial techniques in 1972 and 1973. The Ismetpasa Network was re-measured in 1982 and in 1992 by the Geodesy Working Group of Istanbul Technical University. Although the same network (with five points) was observed in 2002 and 2007 by Zonguldak Karaelmas University applying GPS technique, with 1-hour site occupation, the characteristics of movement has not been detected implicitly. This type of movement still raises a question about the accumulation of tectonic movements in the region. Geodesy Department of Kandilli Observatory and Earthquake Research Institute (KOERI) of Bogazici University has been re-surveyed the network by campaign-based static GPS surveying (10-hour site occupation) since 2005. The GPS velocities data coming from geodynamic GPS networks of the crustal deformation studies and the analysis of repeated geodetic observations give us significant information about the elastic deformation. Therefore, data gathered in this study is processed using GAMIT/GLOBK software and analyzed together with previously collected data to obtain velocity field and strain accumulation in the study area.

Probabilistic evaluation of on-line checks in fault-tolerant multiprocessor systems

NASA Technical Reports Server (NTRS)

Nair, V. S. S.; Hoskote, Yatin V.; Abraham, Jacob A.

1992-01-01

The analysis of fault-tolerant multiprocessor systems that use concurrent error detection (CED) schemes is much more difficult than the analysis of conventional fault-tolerant architectures. Various analytical techniques have been proposed to evaluate CED schemes deterministically. However, these approaches are based on worst-case assumptions related to the failure of system components. Often, the evaluation results do not reflect the actual fault tolerance capabilities of the system. A probabilistic approach to evaluate the fault detecting and locating capabilities of on-line checks in a system is developed. The various probabilities associated with the checking schemes are identified and used in the framework of the matrix-based model. Based on these probabilistic matrices, estimates for the fault tolerance capabilities of various systems are derived analytically.

Integrated Fault Diagnosis Algorithm for Motor Sensors of In-Wheel Independent Drive Electric Vehicles

PubMed Central

Jeon, Namju; Lee, Hyeongcheol

2016-01-01

An integrated fault-diagnosis algorithm for a motor sensor of in-wheel independent drive electric vehicles is presented. This paper proposes a method that integrates the high- and low-level fault diagnoses to improve the robustness and performance of the system. For the high-level fault diagnosis of vehicle dynamics, a planar two-track non-linear model is first selected, and the longitudinal and lateral forces are calculated. To ensure redundancy of the system, correlation between the sensor and residual in the vehicle dynamics is analyzed to detect and separate the fault of the drive motor system of each wheel. To diagnose the motor system for low-level faults, the state equation of an interior permanent magnet synchronous motor is developed, and a parity equation is used to diagnose the fault of the electric current and position sensors. The validity of the high-level fault-diagnosis algorithm is verified using Carsim and Matlab/Simulink co-simulation. The low-level fault diagnosis is verified through Matlab/Simulink simulation and experiments. Finally, according to the residuals of the high- and low-level fault diagnoses, fault-detection flags are defined. On the basis of this information, an integrated fault-diagnosis strategy is proposed. PMID:27973431

Neogene contraction between the San Andreas fault and the Santa Clara Valley, San Francisco Bay region, California

USGS Publications Warehouse

McLaughlin, R.J.; Langenheim, V.E.; Schmidt, K.M.; Jachens, R.C.; Stanley, R.G.; Jayko, A.S.; McDougall, K.A.; Tinsley, J.C.; Valin, Z.C.

1999-01-01

In the southern San Francisco Bay region of California, oblique dextral reverse faults that verge northeastward from the San Andreas fault experienced triggered slip during the 1989 M7.1 Loma Prieta earthquake. The role of these range-front thrusts in the evolution of the San Andreas fault system and the future seismic hazard that they may pose to the urban Santa Clara Valley are poorly understood. Based on recent geologic mapping and geophysical investigations, we propose that the range-front thrust system evolved in conjunction with development of the San Andreas fault system. In the early Miocene, the region was dominated by a system of northwestwardly propagating, basin-bounding, transtensional faults. Beginning as early as middle Miocene time, however, the transtensional faulting was superseded by transpressional NE-stepping thrust and reverse faults of the range-front thrust system. Age constraints on the thrust faults indicate that the locus of contraction has focused on the Monte Vista, Shannon, and Berrocal faults since about 4.8 Ma. Fault slip and fold reconstructions suggest that crustal shortening between the San Andreas fault and the Santa Clara Valley within this time frame is ~21%, amounting to as much as 3.2 km at a rate of 0.6 mm/yr. Rates probably have not remained constant; average rates appear to have been much lower in the past few 100 ka. The distribution of coseismic surface contraction during the Loma Prieta earthquake, active seismicity, late Pleistocene to Holocene fluvial terrace warping, and geodetic data further suggest that the active range-front thrust system includes blind thrusts. Critical unresolved issues include information on the near-surface locations of buried thrusts, the timing of recent thrust earthquake events, and their recurrence in relation to earthquakes on the San Andreas fault.

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

Quinn, Heather; Wirthlin, Michael

A variety of fault emulation systems have been created to study the effect of single-event effects (SEEs) in static random access memory (SRAM) based field-programmable gate arrays (FPGAs). These systems are useful for augmenting radiation-hardness assurance (RHA) methodologies for verifying the effectiveness for mitigation techniques; understanding error signatures and failure modes in FPGAs; and failure rate estimation. For radiation effects researchers, it is important that these systems properly emulate how SEEs manifest in FPGAs. If the fault emulation systems does not mimic the radiation environment, the system will generate erroneous data and incorrect predictions of behavior of the FPGA inmore » a radiation environment. Validation determines whether the emulated faults are reasonable analogs to the radiation-induced faults. In this study we present methods for validating fault emulation systems and provide several examples of validated FPGA fault emulation systems.« less

In-flight Fault Detection and Isolation in Aircraft Flight Control Systems

NASA Technical Reports Server (NTRS)

Azam, Mohammad; Pattipati, Krishna; Allanach, Jeffrey; Poll, Scott; Patterson-Hine, Ann

2005-01-01

In this paper we consider the problem of test design for real-time fault detection and isolation (FDI) in the flight control system of fixed-wing aircraft. We focus on the faults that are manifested in the control surface elements (e.g., aileron, elevator, rudder and stabilizer) of an aircraft. For demonstration purposes, we restrict our focus on the faults belonging to nine basic fault classes. The diagnostic tests are performed on the features extracted from fifty monitored system parameters. The proposed tests are able to uniquely isolate each of the faults at almost all severity levels. A neural network-based flight control simulator, FLTZ(Registered TradeMark), is used for the simulation of various faults in fixed-wing aircraft flight control systems for the purpose of FDI.

From experiment to design -- Fault characterization and detection in parallel computer systems using computational accelerators

NASA Astrophysics Data System (ADS)

Yim, Keun Soo

This dissertation summarizes experimental validation and co-design studies conducted to optimize the fault detection capabilities and overheads in hybrid computer systems (e.g., using CPUs and Graphics Processing Units, or GPUs), and consequently to improve the scalability of parallel computer systems using computational accelerators. The experimental validation studies were conducted to help us understand the failure characteristics of CPU-GPU hybrid computer systems under various types of hardware faults. The main characterization targets were faults that are difficult to detect and/or recover from, e.g., faults that cause long latency failures (Ch. 3), faults in dynamically allocated resources (Ch. 4), faults in GPUs (Ch. 5), faults in MPI programs (Ch. 6), and microarchitecture-level faults with specific timing features (Ch. 7). The co-design studies were based on the characterization results. One of the co-designed systems has a set of source-to-source translators that customize and strategically place error detectors in the source code of target GPU programs (Ch. 5). Another co-designed system uses an extension card to learn the normal behavioral and semantic execution patterns of message-passing processes executing on CPUs, and to detect abnormal behaviors of those parallel processes (Ch. 6). The third co-designed system is a co-processor that has a set of new instructions in order to support software-implemented fault detection techniques (Ch. 7). The work described in this dissertation gains more importance because heterogeneous processors have become an essential component of state-of-the-art supercomputers. GPUs were used in three of the five fastest supercomputers that were operating in 2011. Our work included comprehensive fault characterization studies in CPU-GPU hybrid computers. In CPUs, we monitored the target systems for a long period of time after injecting faults (a temporally comprehensive experiment), and injected faults into various types of program states that included dynamically allocated memory (to be spatially comprehensive). In GPUs, we used fault injection studies to demonstrate the importance of detecting silent data corruption (SDC) errors that are mainly due to the lack of fine-grained protections and the massive use of fault-insensitive data. This dissertation also presents transparent fault tolerance frameworks and techniques that are directly applicable to hybrid computers built using only commercial off-the-shelf hardware components. This dissertation shows that by developing understanding of the failure characteristics and error propagation paths of target programs, we were able to create fault tolerance frameworks and techniques that can quickly detect and recover from hardware faults with low performance and hardware overheads.

Palaeopermeability structure within fault-damage zones: A snap-shot from microfracture analyses in a strike-slip system

NASA Astrophysics Data System (ADS)

Gomila, Rodrigo; Arancibia, Gloria; Mitchell, Thomas M.; Cembrano, Jose M.; Faulkner, Daniel R.

2016-02-01

Understanding fault zone permeability and its spatial distribution allows the assessment of fluid-migration leading to precipitation of hydrothermal minerals. This work is aimed at unraveling the conditions and distribution of fluid transport properties in fault zones based on hydrothermally filled microfractures, which reflect the ''frozen-in'' instantaneous advective hydrothermal activity and record palaeopermeability conditions of the fault-fracture system. We studied the Jorgillo Fault, an exposed 20 km long, left-lateral strike-slip fault, which juxtaposes Jurassic gabbro against metadiorite belonging to the Atacama Fault System in northern Chile. Tracings of microfracture networks of 19 oriented thin sections from a 400 m long transect across the main fault trace was carried out to estimate the hydraulic properties of the low-strain fault damagezone, adjacent to the high-strain fault core, by assuming penny-shaped microfractures of constant radius and aperture within an anisotropic fracture system. Palaeopermeability values of 9.1*10-11 to 3.2*10-13 m2 in the gabbro and of 5.0*10-10 to 1.2*10-13 m2 in the metadiorite were determined, both decreasing perpendicularly away from the fault core. Fracture porosity values range from 40.00% to 0.28%. The Jorgillo Fault has acted as a left-lateral dilational fault-bend, generating large-scale dilation sites north of the JF during co-seismic activity.

Evaluation of reliability modeling tools for advanced fault tolerant systems

NASA Technical Reports Server (NTRS)

Baker, Robert; Scheper, Charlotte

1986-01-01

The Computer Aided Reliability Estimation (CARE III) and Automated Reliability Interactice Estimation System (ARIES 82) reliability tools for application to advanced fault tolerance aerospace systems were evaluated. To determine reliability modeling requirements, the evaluation focused on the Draper Laboratories' Advanced Information Processing System (AIPS) architecture as an example architecture for fault tolerance aerospace systems. Advantages and limitations were identified for each reliability evaluation tool. The CARE III program was designed primarily for analyzing ultrareliable flight control systems. The ARIES 82 program's primary use was to support university research and teaching. Both CARE III and ARIES 82 were not suited for determining the reliability of complex nodal networks of the type used to interconnect processing sites in the AIPS architecture. It was concluded that ARIES was not suitable for modeling advanced fault tolerant systems. It was further concluded that subject to some limitations (the difficulty in modeling systems with unpowered spare modules, systems where equipment maintenance must be considered, systems where failure depends on the sequence in which faults occurred, and systems where multiple faults greater than a double near coincident faults must be considered), CARE III is best suited for evaluating the reliability of advanced tolerant systems for air transport.

Expert systems for real-time monitoring and fault diagnosis

NASA Technical Reports Server (NTRS)

Edwards, S. J.; Caglayan, A. K.

1989-01-01

Methods for building real-time onboard expert systems were investigated, and the use of expert systems technology was demonstrated in improving the performance of current real-time onboard monitoring and fault diagnosis applications. The potential applications of the proposed research include an expert system environment allowing the integration of expert systems into conventional time-critical application solutions, a grammar for describing the discrete event behavior of monitoring and fault diagnosis systems, and their applications to new real-time hardware fault diagnosis and monitoring systems for aircraft.

Ultrareliable fault-tolerant control systems

NASA Technical Reports Server (NTRS)

Webster, L. D.; Slykhouse, R. A.; Booth, L. A., Jr.; Carson, T. M.; Davis, G. J.; Howard, J. C.

1984-01-01

It is demonstrated that fault-tolerant computer systems, such as on the Shuttles, based on redundant, independent operation are a viable alternative in fault tolerant system designs. The ultrareliable fault-tolerant control system (UFTCS) was developed and tested in laboratory simulations of an UH-1H helicopter. UFTCS includes asymptotically stable independent control elements in a parallel, cross-linked system environment. Static redundancy provides the fault tolerance. A polling is performed among the computers, with results allowing for time-delay channel variations with tight bounds. When compared with the laboratory and actual flight data for the helicopter, the probability of a fault was, for the first 10 hr of flight given a quintuple computer redundancy, found to be 1 in 290 billion. Two weeks of untended Space Station operations would experience a fault probability of 1 in 24 million. Techniques for avoiding channel divergence problems are identified.

Award ER25750: Coordinated Infrastructure for Fault Tolerance Systems Indiana University Final Report

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

Lumsdaine, Andrew

2013-03-08

The main purpose of the Coordinated Infrastructure for Fault Tolerance in Systems initiative has been to conduct research with a goal of providing end-to-end fault tolerance on a systemwide basis for applications and other system software. While fault tolerance has been an integral part of most high-performance computing (HPC) system software developed over the past decade, it has been treated mostly as a collection of isolated stovepipes. Visibility and response to faults has typically been limited to the particular hardware and software subsystems in which they are initially observed. Little fault information is shared across subsystems, allowing little flexibility ormore » control on a system-wide basis, making it practically impossible to provide cohesive end-to-end fault tolerance in support of scientific applications. As an example, consider faults such as communication link failures that can be seen by a network library but are not directly visible to the job scheduler, or consider faults related to node failures that can be detected by system monitoring software but are not inherently visible to the resource manager. If information about such faults could be shared by the network libraries or monitoring software, then other system software, such as a resource manager or job scheduler, could ensure that failed nodes or failed network links were excluded from further job allocations and that further diagnosis could be performed. As a founding member and one of the lead developers of the Open MPI project, our efforts over the course of this project have been focused on making Open MPI more robust to failures by supporting various fault tolerance techniques, and using fault information exchange and coordination between MPI and the HPC system software stack from the application, numeric libraries, and programming language runtime to other common system components such as jobs schedulers, resource managers, and monitoring tools.« less

Fault tolerant operation of switched reluctance machine

NASA Astrophysics Data System (ADS)

Wang, Wei

The energy crisis and environmental challenges have driven industry towards more energy efficient solutions. With nearly 60% of electricity consumed by various electric machines in industry sector, advancement in the efficiency of the electric drive system is of vital importance. Adjustable speed drive system (ASDS) provides excellent speed regulation and dynamic performance as well as dramatically improved system efficiency compared with conventional motors without electronics drives. Industry has witnessed tremendous grow in ASDS applications not only as a driving force but also as an electric auxiliary system for replacing bulky and low efficiency auxiliary hydraulic and mechanical systems. With the vast penetration of ASDS, its fault tolerant operation capability is more widely recognized as an important feature of drive performance especially for aerospace, automotive applications and other industrial drive applications demanding high reliability. The Switched Reluctance Machine (SRM), a low cost, highly reliable electric machine with fault tolerant operation capability, has drawn substantial attention in the past three decades. Nevertheless, SRM is not free of fault. Certain faults such as converter faults, sensor faults, winding shorts, eccentricity and position sensor faults are commonly shared among all ASDS. In this dissertation, a thorough understanding of various faults and their influence on transient and steady state performance of SRM is developed via simulation and experimental study, providing necessary knowledge for fault detection and post fault management. Lumped parameter models are established for fast real time simulation and drive control. Based on the behavior of the faults, a fault detection scheme is developed for the purpose of fast and reliable fault diagnosis. In order to improve the SRM power and torque capacity under faults, the maximum torque per ampere excitation are conceptualized and validated through theoretical analysis and experiments. With the proposed optimal waveform, torque production is greatly improved under the same Root Mean Square (RMS) current constraint. Additionally, position sensorless operation methods under phase faults are investigated to account for the combination of physical position sensor and phase winding faults. A comprehensive solution for position sensorless operation under single and multiple phases fault are proposed and validated through experiments. Continuous position sensorless operation with seamless transition between various numbers of phase fault is achieved.

Design of on-board Bluetooth wireless network system based on fault-tolerant technology

NASA Astrophysics Data System (ADS)

You, Zheng; Zhang, Xiangqi; Yu, Shijie; Tian, Hexiang

2007-11-01

In this paper, the Bluetooth wireless data transmission technology is applied in on-board computer system, to realize wireless data transmission between peripherals of the micro-satellite integrating electronic system, and in view of the high demand of reliability of a micro-satellite, a design of Bluetooth wireless network based on fault-tolerant technology is introduced. The reliability of two fault-tolerant systems is estimated firstly using Markov model, then the structural design of this fault-tolerant system is introduced; several protocols are established to make the system operate correctly, some related problems are listed and analyzed, with emphasis on Fault Auto-diagnosis System, Active-standby switch design and Data-Integrity process.

Slip accumulation and lateral propagation of active normal faults in Afar

NASA Astrophysics Data System (ADS)

Manighetti, I.; King, G. C. P.; Gaudemer, Y.; Scholz, C. H.; Doubre, C.

2001-01-01

We investigate fault growth in Afar, where normal fault systems are known to be currently growing fast and most are propagating to the northwest. Using digital elevation models, we have examined the cumulative slip distribution along 255 faults with lengths ranging from 0.3 to 60 km. Faults exhibiting the elliptical or "bell-shaped" slip profiles predicted by simple linear elastic fracture mechanics or elastic-plastic theories are rare. Most slip profiles are roughly linear for more than half of their length, with overall slopes always <0.035. For the dominant population of NW striking faults and fault systems longer than 2 km, the slip profiles are asymmetric, with slip being maximum near the eastern ends of the profiles where it drops abruptly to zero, whereas slip decreases roughly linearly and tapers in the direction of overall Aden rift propagation. At a more detailed level, most faults appear to be composed of distinct, shorter subfaults or segments, whose slip profiles, while different from one to the next, combine to produce the roughly linear overall slip decrease along the entire fault. On a larger scale, faults cluster into kinematically coupled systems, along which the slip on any scale individual fault or fault system complements that of its neighbors, so that the total slip of the whole system is roughly linearly related to its length, with an average slope again <0.035. We discuss the origin of these quasilinear, asymmetric profiles in terms of "initiation points" where slip starts, and "barriers" where fault propagation is arrested. In the absence of a barrier, slip apparently extends with a roughly linear profile, tapered in the direction of fault propagation.

Comparing Different Fault Identification Algorithms in Distributed Power System

NASA Astrophysics Data System (ADS)

Alkaabi, Salim

A power system is a huge complex system that delivers the electrical power from the generation units to the consumers. As the demand for electrical power increases, distributed power generation was introduced to the power system. Faults may occur in the power system at any time in different locations. These faults cause a huge damage to the system as they might lead to full failure of the power system. Using distributed generation in the power system made it even harder to identify the location of the faults in the system. The main objective of this work is to test the different fault location identification algorithms while tested on a power system with the different amount of power injected using distributed generators. As faults may lead the system to full failure, this is an important area for research. In this thesis different fault location identification algorithms have been tested and compared while the different amount of power is injected from distributed generators. The algorithms were tested on IEEE 34 node test feeder using MATLAB and the results were compared to find when these algorithms might fail and the reliability of these methods.

Automatic translation of digraph to fault-tree models

NASA Technical Reports Server (NTRS)

Iverson, David L.

1992-01-01

The author presents a technique for converting digraph models, including those models containing cycles, to a fault-tree format. A computer program which automatically performs this translation using an object-oriented representation of the models has been developed. The fault-trees resulting from translations can be used for fault-tree analysis and diagnosis. Programs to calculate fault-tree and digraph cut sets and perform diagnosis with fault-tree models have also been developed. The digraph to fault-tree translation system has been successfully tested on several digraphs of varying size and complexity. Details of some representative translation problems are presented. Most of the computation performed by the program is dedicated to finding minimal cut sets for digraph nodes in order to break cycles in the digraph. Fault-trees produced by the translator have been successfully used with NASA's Fault-Tree Diagnosis System (FTDS) to produce automated diagnostic systems.

Fault tolerant architectures for integrated aircraft electronics systems, task 2

NASA Technical Reports Server (NTRS)

Levitt, K. N.; Melliar-Smith, P. M.; Schwartz, R. L.

1984-01-01

The architectural basis for an advanced fault tolerant on-board computer to succeed the current generation of fault tolerant computers is examined. The network error tolerant system architecture is studied with particular attention to intercluster configurations and communication protocols, and to refined reliability estimates. The diagnosis of faults, so that appropriate choices for reconfiguration can be made is discussed. The analysis relates particularly to the recognition of transient faults in a system with tasks at many levels of priority. The demand driven data-flow architecture, which appears to have possible application in fault tolerant systems is described and work investigating the feasibility of automatic generation of aircraft flight control programs from abstract specifications is reported.

Nonlinear dynamic failure process of tunnel-fault system in response to strong seismic event

NASA Astrophysics Data System (ADS)

Yang, Zhihua; Lan, Hengxing; Zhang, Yongshuang; Gao, Xing; Li, Langping

2013-03-01

Strong earthquakes and faults have significant effect on the stability capability of underground tunnel structures. This study used a 3-Dimensional Discrete Element model and the real records of ground motion in the Wenchuan earthquake to investigate the dynamic response of tunnel-fault system. The typical tunnel-fault system was composed of one planned railway tunnel and one seismically active fault. The discrete numerical model was prudentially calibrated by means of the comparison between the field survey and numerical results of ground motion. It was then used to examine the detailed quantitative information on the dynamic response characteristics of tunnel-fault system, including stress distribution, strain, vibration velocity and tunnel failure process. The intensive tunnel-fault interaction during seismic loading induces the dramatic stress redistribution and stress concentration in the intersection of tunnel and fault. The tunnel-fault system behavior is characterized by the complicated nonlinear dynamic failure process in response to a real strong seismic event. It can be qualitatively divided into 5 main stages in terms of its stress, strain and rupturing behaviors: (1) strain localization, (2) rupture initiation, (3) rupture acceleration, (4) spontaneous rupture growth and (5) stabilization. This study provides the insight into the further stability estimation of underground tunnel structures under the combined effect of strong earthquakes and faults.

Orion GN&C Fault Management System Verification: Scope And Methodology

NASA Technical Reports Server (NTRS)

Brown, Denise; Weiler, David; Flanary, Ronald

2016-01-01

In order to ensure long-term ability to meet mission goals and to provide for the safety of the public, ground personnel, and any crew members, nearly all spacecraft include a fault management (FM) system. For a manned vehicle such as Orion, the safety of the crew is of paramount importance. The goal of the Orion Guidance, Navigation and Control (GN&C) fault management system is to detect, isolate, and respond to faults before they can result in harm to the human crew or loss of the spacecraft. Verification of fault management/fault protection capability is challenging due to the large number of possible faults in a complex spacecraft, the inherent unpredictability of faults, the complexity of interactions among the various spacecraft components, and the inability to easily quantify human reactions to failure scenarios. The Orion GN&C Fault Detection, Isolation, and Recovery (FDIR) team has developed a methodology for bounding the scope of FM system verification while ensuring sufficient coverage of the failure space and providing high confidence that the fault management system meets all safety requirements. The methodology utilizes a swarm search algorithm to identify failure cases that can result in catastrophic loss of the crew or the vehicle and rare event sequential Monte Carlo to verify safety and FDIR performance requirements.

Evidence for Phanerozoic reactivation of the Najd Fault System in AVHRR, TM, and SPOT images of central Arabia

NASA Technical Reports Server (NTRS)

Andre, Constance G.

1989-01-01

SPOT stereoscopic and TM multispectral images support evidence in AVHRR thermal-IR images of a major unmapped shear zone in Phanerozoic cover rocks southeast of the ancient Najd Fault System in the Arabian Shield. This shear zone and faults of the Najd share a common alignment, orientation, and sinistral sense of movement. These similarities suggest a 200-km extension of the Najd Fault System and reactivation since it formed in the late Precambrian. Topographic and lithologic features in the TM and SPOT data along one of three faults inferred from the AVHRR data indicate sinistral offsets up to 2.5 km, en echelon folds and secondary faults like those predicted by models of left-lateral strike-slip faulting. The age of the affected outcrops indicates reactivation of Najd faults in the Cretaceous, judging from TM and SPOT data or in the Tertiary, based on AVHRR data. The total length of the system visible at the surface measures 1300 km. If the Najd Fault System is extrapolated beneath sands of the Empty Quarter to faults of a similar trend in South Yemen, the shear zone would span the Arabian Plate. Furthermore, if extensions into the Arabian Sea bed and into Egypt proposed by others are considered, it would exceed 3000 km.

A fault diagnosis system for PV power station based on global partitioned gradually approximation method

NASA Astrophysics Data System (ADS)

Wang, S.; Zhang, X. N.; Gao, D. D.; Liu, H. X.; Ye, J.; Li, L. R.

2016-08-01

As the solar photovoltaic (PV) power is applied extensively, more attentions are paid to the maintenance and fault diagnosis of PV power plants. Based on analysis of the structure of PV power station, the global partitioned gradually approximation method is proposed as a fault diagnosis algorithm to determine and locate the fault of PV panels. The PV array is divided into 16x16 blocks and numbered. On the basis of modularly processing of the PV array, the current values of each block are analyzed. The mean current value of each block is used for calculating the fault weigh factor. The fault threshold is defined to determine the fault, and the shade is considered to reduce the probability of misjudgments. A fault diagnosis system is designed and implemented with LabVIEW. And it has some functions including the data realtime display, online check, statistics, real-time prediction and fault diagnosis. Through the data from PV plants, the algorithm is verified. The results show that the fault diagnosis results are accurate, and the system works well. The validity and the possibility of the system are verified by the results as well. The developed system will be benefit for the maintenance and management of large scale PV array.

Software fault tolerance in computer operating systems

NASA Technical Reports Server (NTRS)

Iyer, Ravishankar K.; Lee, Inhwan

1994-01-01

This chapter provides data and analysis of the dependability and fault tolerance for three operating systems: the Tandem/GUARDIAN fault-tolerant system, the VAX/VMS distributed system, and the IBM/MVS system. Based on measurements from these systems, basic software error characteristics are investigated. Fault tolerance in operating systems resulting from the use of process pairs and recovery routines is evaluated. Two levels of models are developed to analyze error and recovery processes inside an operating system and interactions among multiple instances of an operating system running in a distributed environment. The measurements show that the use of process pairs in Tandem systems, which was originally intended for tolerating hardware faults, allows the system to tolerate about 70% of defects in system software that result in processor failures. The loose coupling between processors which results in the backup execution (the processor state and the sequence of events occurring) being different from the original execution is a major reason for the measured software fault tolerance. The IBM/MVS system fault tolerance almost doubles when recovery routines are provided, in comparison to the case in which no recovery routines are available. However, even when recovery routines are provided, there is almost a 50% chance of system failure when critical system jobs are involved.

Possible strand of the North Anatolian fault in the Thrace basin, Turkey - An interpretation

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

Perincek, D.

1991-02-01

This study focuses on the presence of a major strike-slip fault system in the Thrace basin. This new discovery is important for the geology of the Thrace basin and also brings a new perspective to petroleum exploration. The wrench fault system is named the Thrace strike-slip fault system (Perincek, 1988). Similarities with the North Anatolian fault zone prompted an investigation of the relationship between these two fault system.s The study area covers most of the Thrace region of Turkey. The purposes of this paper are (1) to outline the geometry of the Thrace fault system, (2) to demonstrate its tectonicmore » relation with other major structures of the region, (3) to define the age of its inception, and (4) to discuss possible magnitudes of the lateral displacement. The interpretation is based mainly on seismic data consisting of 180 seismic reflection profiles that have a total cumulative length of 2,800 km. Seismic data are complemented with subsurface control from 54 wells.« less

Critical fault patterns determination in fault-tolerant computer systems

NASA Technical Reports Server (NTRS)

Mccluskey, E. J.; Losq, J.

1978-01-01

The method proposed tries to enumerate all the critical fault-patterns (successive occurrences of failures) without analyzing every single possible fault. The conditions for the system to be operating in a given mode can be expressed in terms of the static states. Thus, one can find all the system states that correspond to a given critical mode of operation. The next step consists in analyzing the fault-detection mechanisms, the diagnosis algorithm and the process of switch control. From them, one can find all the possible system configurations that can result from a failure occurrence. Thus, one can list all the characteristics, with respect to detection, diagnosis, and switch control, that failures must have to constitute critical fault-patterns. Such an enumeration of the critical fault-patterns can be directly used to evaluate the overall system tolerance to failures. Present research is focused on how to efficiently make use of these system-level characteristics to enumerate all the failures that verify these characteristics.

Practical Methods for Estimating Software Systems Fault Content and Location

NASA Technical Reports Server (NTRS)

Nikora, A.; Schneidewind, N.; Munson, J.

1999-01-01

Over the past several years, we have developed techniques to discriminate between fault-prone software modules and those that are not, to estimate a software system's residual fault content, to identify those portions of a software system having the highest estimated number of faults, and to estimate the effects of requirements changes on software quality.

Fault diagnosis

NASA Technical Reports Server (NTRS)

Abbott, Kathy

1990-01-01

The objective of the research in this area of fault management is to develop and implement a decision aiding concept for diagnosing faults, especially faults which are difficult for pilots to identify, and to develop methods for presenting the diagnosis information to the flight crew in a timely and comprehensible manner. The requirements for the diagnosis concept were identified by interviewing pilots, analyzing actual incident and accident cases, and examining psychology literature on how humans perform diagnosis. The diagnosis decision aiding concept developed based on those requirements takes abnormal sensor readings as input, as identified by a fault monitor. Based on these abnormal sensor readings, the diagnosis concept identifies the cause or source of the fault and all components affected by the fault. This concept was implemented for diagnosis of aircraft propulsion and hydraulic subsystems in a computer program called Draphys (Diagnostic Reasoning About Physical Systems). Draphys is unique in two important ways. First, it uses models of both functional and physical relationships in the subsystems. Using both models enables the diagnostic reasoning to identify the fault propagation as the faulted system continues to operate, and to diagnose physical damage. Draphys also reasons about behavior of the faulted system over time, to eliminate possibilities as more information becomes available, and to update the system status as more components are affected by the fault. The crew interface research is examining display issues associated with presenting diagnosis information to the flight crew. One study examined issues for presenting system status information. One lesson learned from that study was that pilots found fault situations to be more complex if they involved multiple subsystems. Another was pilots could identify the faulted systems more quickly if the system status was presented in pictorial or text format. Another study is currently under way to examine pilot mental models of the aircraft subsystems and their use in diagnosis tasks. Future research plans include piloted simulation evaluation of the diagnosis decision aiding concepts and crew interface issues. Information is given in viewgraph form.

cost and benefits optimization model for fault-tolerant aircraft electronic systems

NASA Technical Reports Server (NTRS)

1983-01-01

The factors involved in economic assessment of fault tolerant systems (FTS) and fault tolerant flight control systems (FTFCS) are discussed. Algorithms for optimization and economic analysis of FTFCS are documented.

Intracontinental movements in Western Gondwanaland: a palaeomagnetic test

NASA Astrophysics Data System (ADS)

Rapalini, A. E.; Abdeldayem, A. L.; Tarling, D. H.

1993-04-01

Early Cretaceous intracontinental movements within Africa and/or South America, to account for misfit problem in the pre-drift reconstruction of Western Gondwana, have been tested using palaeomagnetic poles from both continents. Each continent has been considered as comprising separate subplates according to the boundaries proposed by Pindell and Dewey (1982) and Curie (1983): i.e., northern Africa ( NAF), southern Africa ( SAF), northern South America (nsa) and southern South America ( SSA). Visual and statistical distribution of Late Permian to Jurassic poles from the African subplates indicate two distinct groups before rotating SAF relative to NAF, while after the rotation they become indistinguishable. The distribution and sparsity of data from South America limit the study in this continent as the data are statistically indistinguishable before and after rotation of SSA with respect to NSA. When the test is extended to the reconstruction of Western Gondwana, the tightest grouping of the poles occurs when an intracontinental movement is assumed within Africa. This suggests that the misfit between the two continents is probably due to intracontinental deformation within Africa and not in South America. If confirmed, this may have profound implications in the kinematics of the processes related to the opening of the South and Central Atlantic Oceans and also the origin of the West African Rift System.

Role of the Precambrian Mughese Shear Zone on Cenozoic faulting along the Rukwa-Malawi Rift segment of the East African Rift System

NASA Astrophysics Data System (ADS)

Heilman, E.; Kolawole, F.; Mayle, M.; Atekwana, E. A.; Abdelsalam, M. G.

2017-12-01

We address the longstanding question of the role of long-lived basement structures in strain accommodation within active rift systems. Studies have highlighted the influence of pre-existing zones of lithospheric weakness in modulating faulting and fault kinematics. Here, we investigate the role of the Neoproterozoic Mughese Shear Zone (MSZ) in Cenozoic rifting along the Rukwa-Malawi rift segment of the East African Rift System (EARS). Detailed analyses of Shuttle Radar Topography Mission (SRTM) DEM and filtered aeromagnetic data allowed us to determine the relationship between rift-related basement-rooted normal faults and the MSZ fabric extending along the southern boundary of the Rukwa-Malawi Rift North Basin. Our results show that the magnetic lineaments defining the MSZ coincide with the collinear Rukwa Rift border fault (Ufipa Fault), a dextral strike-slip fault (Mughese Fault), and the North Basin hinge-zone fault (Mbiri Fault). Fault-scarp and minimum fault-throw analyses reveal that within the Rukwa Rift, the Ufipa Border Fault has been accommodating significant displacement relative to the Lupa Border Fault, which represents the northeastern border fault of the Rukwa Rift. Our analysis also shows that within the North Basin half-graben, the Mbiri Fault has accommodated the most vertical displacement relative to other faults along the half-graben hinge zone. We propose that the Cenozoic reactivation along the MSZ facilitated significant normal slip displacement along the Ufipa Border Fault and the Mbiri Fault, and minor dextral strike-slip between the two faults. We suggest that the fault kinematics along the Rukwa-Malawi Rift is the result of reactivation of the MSZ through regional oblique extension.

ARGES: an Expert System for Fault Diagnosis Within Space-Based ECLS Systems

NASA Technical Reports Server (NTRS)

Pachura, David W.; Suleiman, Salem A.; Mendler, Andrew P.

1988-01-01

ARGES (Atmospheric Revitalization Group Expert System) is a demonstration prototype expert system for fault management for the Solid Amine, Water Desorbed (SAWD) CO2 removal assembly, associated with the Environmental Control and Life Support (ECLS) System. ARGES monitors and reduces data in real time from either the SAWD controller or a simulation of the SAWD assembly. It can detect gradual degradations or predict failures. This allows graceful shutdown and scheduled maintenance, which reduces crew maintenance overhead. Status and fault information is presented in a user interface that simulates what would be seen by a crewperson. The user interface employs animated color graphics and an object oriented approach to provide detailed status information, fault identification, and explanation of reasoning in a rapidly assimulated manner. In addition, ARGES recommends possible courses of action for predicted and actual faults. ARGES is seen as a forerunner of AI-based fault management systems for manned space systems.

Sliding Mode Observer-Based Current Sensor Fault Reconstruction and Unknown Load Disturbance Estimation for PMSM Driven System

PubMed Central

Li, Xiangfei; Lin, Yuliang

2017-01-01

This paper proposes a new scheme of reconstructing current sensor faults and estimating unknown load disturbance for a permanent magnet synchronous motor (PMSM)-driven system. First, the original PMSM system is transformed into two subsystems; the first subsystem has unknown system load disturbances, which are unrelated to sensor faults, and the second subsystem has sensor faults, but is free from unknown load disturbances. Introducing a new state variable, the augmented subsystem that has sensor faults can be transformed into having actuator faults. Second, two sliding mode observers (SMOs) are designed: the unknown load disturbance is estimated by the first SMO in the subsystem, which has unknown load disturbance, and the sensor faults can be reconstructed using the second SMO in the augmented subsystem, which has sensor faults. The gains of the proposed SMOs and their stability analysis are developed via the solution of linear matrix inequality (LMI). Finally, the effectiveness of the proposed scheme was verified by simulations and experiments. The results demonstrate that the proposed scheme can reconstruct current sensor faults and estimate unknown load disturbance for the PMSM-driven system. PMID:29211017

Model-Based Diagnostics for Propellant Loading Systems

NASA Technical Reports Server (NTRS)

Daigle, Matthew John; Foygel, Michael; Smelyanskiy, Vadim N.

2011-01-01

The loading of spacecraft propellants is a complex, risky operation. Therefore, diagnostic solutions are necessary to quickly identify when a fault occurs, so that recovery actions can be taken or an abort procedure can be initiated. Model-based diagnosis solutions, established using an in-depth analysis and understanding of the underlying physical processes, offer the advanced capability to quickly detect and isolate faults, identify their severity, and predict their effects on system performance. We develop a physics-based model of a cryogenic propellant loading system, which describes the complex dynamics of liquid hydrogen filling from a storage tank to an external vehicle tank, as well as the influence of different faults on this process. The model takes into account the main physical processes such as highly nonequilibrium condensation and evaporation of the hydrogen vapor, pressurization, and also the dynamics of liquid hydrogen and vapor flows inside the system in the presence of helium gas. Since the model incorporates multiple faults in the system, it provides a suitable framework for model-based diagnostics and prognostics algorithms. Using this model, we analyze the effects of faults on the system, derive symbolic fault signatures for the purposes of fault isolation, and perform fault identification using a particle filter approach. We demonstrate the detection, isolation, and identification of a number of faults using simulation-based experiments.

Active Structures as Deduced from Geomorphic Features: A case in Hsinchu Area, northwestern Taiwan

NASA Astrophysics Data System (ADS)

Chen, Y.; Shyu, J.; Ota, Y.; Chen, W.; Hu, J.; Tsai, B.; Wang, Y.

2002-12-01

Hsinchu area is located in the northwestern Taiwan, the fold-and thrust belt created by arc-continent collision between Eurasian and Philippine. Since the collision event is still ongoing, the island is tectonically active and full of active faults. According to the historical records, some of the faults are seismically acting. In Hsinchuarea two active faults, the Hsinchu and Hsincheng, have been previously mapped. To evaluate the recent activities, we studied the related geomorphic features by using newly developed Digital Elevation Model (DEM), the aerial photos and field investigation. Geologically, both of the faults are coupled with a hanging wall anticline. The anticlines are recently active due to the deformation of the geomorphic surfaces. The Hsinchu fault system shows complicate corresponding scarps, distributed sub-parallel to the fault trace previously suggested by projection of subsurface geology. This is probably caused by its strike-slip component tearing the surrounding area along the main trace. The scarps associated with the Hsincheng fault system are rather simple and unique. It offsets a flight of terraces all the way down to recent flood plain, indicating its long lasting activity. One to two kilometers to east of main trace a back-thrust is found, showing coupled vertical surface offsets with the main fault. The striking discovery in this study is that the surface deformation is only distributed in the southern bank of Touchien river, also suddenly decreasing when crossing another tear fault system, which is originated from Hsincheng fault in the west and extending southeastward parallel to the Touchien river. The strike-slip fault system mentioned above not only bisects the Hsinchu fault, but also divides the Hsincheng fault into segments. The supporting evidence found in this study includes pressure ridges and depressions. As a whole, the study area is tectonically dominated by three active fault systems and two actively growing anticlines. The interactions between active structural systems formed the complicate geomorphic features presented in this paper.

An Ontology for Identifying Cyber Intrusion Induced Faults in Process Control Systems

NASA Astrophysics Data System (ADS)

Hieb, Jeffrey; Graham, James; Guan, Jian

This paper presents an ontological framework that permits formal representations of process control systems, including elements of the process being controlled and the control system itself. A fault diagnosis algorithm based on the ontological model is also presented. The algorithm can identify traditional process elements as well as control system elements (e.g., IP network and SCADA protocol) as fault sources. When these elements are identified as a likely fault source, the possibility exists that the process fault is induced by a cyber intrusion. A laboratory-scale distillation column is used to illustrate the model and the algorithm. Coupled with a well-defined statistical process model, this fault diagnosis approach provides cyber security enhanced fault diagnosis information to plant operators and can help identify that a cyber attack is underway before a major process failure is experienced.

Solar Photovoltaic (PV) Distributed Generation Systems - Control and Protection

NASA Astrophysics Data System (ADS)

Yi, Zhehan

This dissertation proposes a comprehensive control, power management, and fault detection strategy for solar photovoltaic (PV) distribution generations. Battery storages are typically employed in PV systems to mitigate the power fluctuation caused by unstable solar irradiance. With AC and DC loads, a PV-battery system can be treated as a hybrid microgrid which contains both DC and AC power resources and buses. In this thesis, a control power and management system (CAPMS) for PV-battery hybrid microgrid is proposed, which provides 1) the DC and AC bus voltage and AC frequency regulating scheme and controllers designed to track set points; 2) a power flow management strategy in the hybrid microgrid to achieve system generation and demand balance in both grid-connected and islanded modes; 3) smooth transition control during grid reconnection by frequency and phase synchronization control between the main grid and microgrid. Due to the increasing demands for PV power, scales of PV systems are getting larger and fault detection in PV arrays becomes challenging. High-impedance faults, low-mismatch faults, and faults occurred in low irradiance conditions tend to be hidden due to low fault currents, particularly, when a PV maximum power point tracking (MPPT) algorithm is in-service. If remain undetected, these faults can considerably lower the output energy of solar systems, damage the panels, and potentially cause fire hazards. In this dissertation, fault detection challenges in PV arrays are analyzed in depth, considering the crossing relations among the characteristics of PV, interactions with MPPT algorithms, and the nature of solar irradiance. Two fault detection schemes are then designed as attempts to address these technical issues, which detect faults inside PV arrays accurately even under challenging circumstances, e.g., faults in low irradiance conditions or high-impedance faults. Taking advantage of multi-resolution signal decomposition (MSD), a powerful signal processing technique based on discrete wavelet transformation (DWT), the first attempt is devised, which extracts the features of both line-to-line (L-L) and line-to-ground (L-G) faults and employs a fuzzy inference system (FIS) for the decision-making stage of fault detection. This scheme is then improved as the second attempt by further studying the system's behaviors during L-L faults, extracting more efficient fault features, and devising a more advanced decision-making stage: the two-stage support vector machine (SVM). For the first time, the two-stage SVM method is proposed in this dissertation to detect L-L faults in PV system with satisfactory accuracies. Numerous simulation and experimental case studies are carried out to verify the proposed control and protection strategies. Simulation environment is set up using the PSCAD/EMTDC and Matlab/Simulink software packages. Experimental case studies are conducted in a PV-battery hybrid microgrid using the dSPACE real-time controller to demonstrate the ease of hardware implementation and the controller performance. Another small-scale grid-connected PV system is set up to verify both fault detection algorithms which demonstrate promising performances and fault detecting accuracies.

Solar system fault detection

DOEpatents

Farrington, R.B.; Pruett, J.C. Jr.

1984-05-14

A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

Solar system fault detection

DOEpatents

Farrington, Robert B.; Pruett, Jr., James C.

1986-01-01

A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

Real-time fault diagnosis for propulsion systems

NASA Technical Reports Server (NTRS)

Merrill, Walter C.; Guo, Ten-Huei; Delaat, John C.; Duyar, Ahmet

1991-01-01

Current research toward real time fault diagnosis for propulsion systems at NASA-Lewis is described. The research is being applied to both air breathing and rocket propulsion systems. Topics include fault detection methods including neural networks, system modeling, and real time implementations.

The Gabbs Valley, Nevada, geothermal prospect: Exploring for a potential blind geothermal resource

NASA Astrophysics Data System (ADS)

Payne, J.; Bell, J. W.; Calvin, W. M.

2012-12-01

The Gabbs Valley prospect in west-central Nevada is a potential blind geothermal resource system. Possible structural controls on this system were investigated using high-resolution LiDAR, low sun-angle aerial (LSA) photography, exploratory fault trenching and a shallow temperature survey. Active Holocene faults have previously been identified at 37 geothermal systems with indication of temperatures greater than 100° C in the western Nevada region. Active fault controls in Gabbs Valley include both Holocene and historical structures. Two historical earthquakes occurring in 1932 and 1954 have overlapping surface rupture patterns in Gabbs Valley. Three active fault systems identified through LSA and LiDAR mapping have characteristics of Basin and Range normal faulting and Walker Lane oblique dextral faulting. The East Monte Cristo Mountains fault zone is an 8.5 km long continuous NNE striking, discrete fault with roughly 0.5 m right-normal historic motion and 3 m vertical Quaternary separation. The Phillips Wash fault zone is an 8.2 km long distributed fault system striking NE to N, with Quaternary fault scarps of 1-3 m vertical separation and a 500 m wide graben adjacent to the Cobble Cuesta anticline. This fault displays ponded drainages, an offset terrace riser and right stepping en echelon fault patterns suggestive of left lateral offset, and fault trenching exposed non-matching stratigraphy typical of a significant component of lateral offset. The unnamed faults of Gabbs Valley are a 10.6 km long system of normal faults striking NNE and Quaternary scarps are up to 4 m high. These normal faults largely do not have historic surface rupture, but a small segment of 1932 rupture has been identified. A shallow (2 m deep) temperature survey of 80 points covering roughly 65 square kilometers was completed. Data were collected over approximately 2 months, and continual base station temperature measurements were used to seasonally correct temperature measurements. A 2.5 km long temperature anomaly greater than 3° C above background temperatures forms west-northwest trending zone between terminations of the Phillips Wash fault zone and unnamed faults of Gabbs Valley to the south. Rupture segments of two young active faults bracket the temperature anomaly. The temperature anomaly may be due to several possible causes. 1. Increases in stress near the rupture segments or tip-lines of these faults, or where multiple fault splays exist, can increase fault permeability. The un-ruptured segments of these faults may be controlling the location of the Gabbs Valley thermal anomaly between ruptured segments of the 1932 Cedar Mountain and 1954 Fairview Peak earthquakes. 2. Numerous unnamed normal faults may interact and the hanging wall of these faults is hosting the thermal anomaly. The size and extent of the anomaly may be due to its proximity to a flat playa and not the direct location of the shallow heat anomaly. 3. The linear northwest nature of the thermal anomaly may reflect a hydrologic barrier in the subsurface controlling where heated fluids rise. A concealed NW- striking fault is possible, but has not been identified in previous studies or in the LiDAR or LSA fault mapping.

Nearly frictionless faulting by unclamping in long-term interaction models

USGS Publications Warehouse

Parsons, T.

2002-01-01

In defiance of direct rock-friction observations, some transform faults appear to slide with little resistance. In this paper finite element models are used to show how strain energy is minimized by interacting faults that can cause long-term reduction in fault-normal stresses (unclamping). A model fault contained within a sheared elastic medium concentrates stress at its end points with increasing slip. If accommodating structures free up the ends, then the fault responds by rotating, lengthening, and unclamping. This concept is illustrated by a comparison between simple strike-slip faulting and a mid-ocean-ridge model with the same total transform length; calculations show that the more complex system unclapms the transforms and operates at lower energy. In another example, the overlapping San Andreas fault system in the San Francisco Bay region is modeled; this system is complicated by junctions and stepovers. A finite element model indicates that the normal stress along parts of the faults could be reduced to hydrostatic levels after ???60-100 k.y. of system-wide slip. If this process occurs in the earth, then parts of major transform fault zones could appear nearly frictionless.

Automatic Detection of Electric Power Troubles (ADEPT)

NASA Technical Reports Server (NTRS)

Wang, Caroline; Zeanah, Hugh; Anderson, Audie; Patrick, Clint; Brady, Mike; Ford, Donnie

1988-01-01

Automatic Detection of Electric Power Troubles (A DEPT) is an expert system that integrates knowledge from three different suppliers to offer an advanced fault-detection system. It is designed for two modes of operation: real time fault isolation and simulated modeling. Real time fault isolation of components is accomplished on a power system breadboard through the Fault Isolation Expert System (FIES II) interface with a rule system developed in-house. Faults are quickly detected and displayed and the rules and chain of reasoning optionally provided on a laser printer. This system consists of a simulated space station power module using direct-current power supplies for solar arrays on three power buses. For tests of the system's ablilty to locate faults inserted via switches, loads are configured by an INTEL microcomputer and the Symbolics artificial intelligence development system. As these loads are resistive in nature, Ohm's Law is used as the basis for rules by which faults are located. The three-bus system can correct faults automatically where there is a surplus of power available on any of the three buses. Techniques developed and used can be applied readily to other control systems requiring rapid intelligent decisions. Simulated modeling, used for theoretical studies, is implemented using a modified version of Kennedy Space Center's KATE (Knowledge-Based Automatic Test Equipment), FIES II windowing, and an ADEPT knowledge base.

Automatic Detection of Electric Power Troubles (ADEPT)

NASA Astrophysics Data System (ADS)

Wang, Caroline; Zeanah, Hugh; Anderson, Audie; Patrick, Clint; Brady, Mike; Ford, Donnie

1988-11-01

Automatic Detection of Electric Power Troubles (A DEPT) is an expert system that integrates knowledge from three different suppliers to offer an advanced fault-detection system. It is designed for two modes of operation: real time fault isolation and simulated modeling. Real time fault isolation of components is accomplished on a power system breadboard through the Fault Isolation Expert System (FIES II) interface with a rule system developed in-house. Faults are quickly detected and displayed and the rules and chain of reasoning optionally provided on a laser printer. This system consists of a simulated space station power module using direct-current power supplies for solar arrays on three power buses. For tests of the system's ablilty to locate faults inserted via switches, loads are configured by an INTEL microcomputer and the Symbolics artificial intelligence development system. As these loads are resistive in nature, Ohm's Law is used as the basis for rules by which faults are located. The three-bus system can correct faults automatically where there is a surplus of power available on any of the three buses. Techniques developed and used can be applied readily to other control systems requiring rapid intelligent decisions. Simulated modeling, used for theoretical studies, is implemented using a modified version of Kennedy Space Center's KATE (Knowledge-Based Automatic Test Equipment), FIES II windowing, and an ADEPT knowledge base.

Seismarmara 2001: A Marine Seismic Survey and Offshore-onshore Artificial Source and Natural Earthquakes In The Seismogenic Region of The Sea of Marmara

NASA Astrophysics Data System (ADS)

Hirn, A.; Singh, S.; Charvis, P.; Géli, L.; Laigle, M.; Lépine, J.-C.; de Voogd, B.; Saatcilar, R.; Taymaz, T.; Ozalaybey, S.; Shimamura, H.; Selvi, O.; Karabulut, H.; Murai, Y.; Nishimura, Y.; Yamada, A.; Vigner, A.; Bazin, S.; Tan, O.; Yolsal, S.; Aktar, M.; Galvé, A.; Sapin, M.; Marthelot, J.-M.; Imren, C.; Ergin, M.; Tapirdamaz, C.; Koçaoglu, A.; Tarancioglu, A.; Diaz, J.; Verhille, J.; Auffret, Y.; Cetin, S.; Oçakoglu, N.; Karakoç, F.; Klien, E.; Ricolleau, A.; Selvigen, V.; Demirbag, E.; Hakyemez, Y.; Sarikawak, K.

SEISMARMARA is a Turkish-French survey carried out in July-October 2001 as a multi-method approach of seismic structure and activity of the Sea of Marmara. This is the segment of the North Anatolian Fault system that continues the one that produced the two destructive earthquakes in 1999 to the East, and is prone to future major earth- quakes as it has experienced in the past. Aims of the programme are to shed light on the regional tectonics and recent evolution at crustal scale, image faults by their structure and seismic activity, and provide a model and reference to improve loca- tion of earthquakes and focal mechanism studies. The programme bases on marine multichannel reflection seismics (MCS), ocean bottom seismometers (OBS) and land stations recording of wide-angle reflection-refraction from the same source, as well as recording of local earthquakes for tomography and stress/strain distribution. The French N/O Le Nadir acquired 4000 km of MCS profiles in the northern Sea of Mar- mara, using a 4.5 km long digital streamer with 360-channels and sources of 8100 cu. in., or 2900 cu. in., provided by a 12-airgun array in single-bubble mode. Navigation safety was provided by a vessel of the Turkish Coast Guards (Sahil Güvenlik), Leg 1 comprises 4 E-W lines and 30 cross-lines in the whole Marmara Trough, leg 2 has 1 been devoted to a very dense grid of lines in the Cinarcik basin and its margins, record- ing over 80 dip-lines at 0.6-0.9 km spacing At sea-bottom 38 OBS, with 3-component sensors and continuous recording over 1 to 2-month in order to also record natural earthquakes were deployed and collected by the Turkish ship MTA Sismik-1. On land the permanent array has been complemented by as many temporary stations, in par- ticular over 30 continuous recording 3-component 2 Hz stations. Refraction seismics from offshore to onshore was further implemented by short-duration deployments of vertical component lightweight instruments with short recording capacity. A teleseis- mic recording effort with temporary stations, tested in the previous year concentrated on a line through the NAF East of Izmit 2

Geology along the Fairweather-Queen Charlotte fault system off southeast Alaska and British Columbia from GLORIA images and seismic-reflection data

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

Bruns, T.R.; Carlson, P.R.; Stevenson, A.J.

1990-06-01

GLORIA images collected in 1989 along southeast Alaska and British Columbia strikingly show the active trace of the Fairweather-Queen Charlotte transform fault system beneath the outer shelf and slope; seismic-reflection data are used to track the fault system across the continental shelf where GLORIA data are not available. From Cross Sound to Chatham Strait, the fault system is comprised of two sets of subparallel fault traces separated by 3 to 6 km. The fault system crosses the shelf from Icy Point to south of Yakobi Valley, then follows the shelf edge to Chatham Strait. Between Chatham Strait and Dixon Entrance,more » a single, sharply defined active fault trace underlies the upper and middle slope. This fault segment is bounded on the seaward side by a high, midslope ridge and by lower slope Quaternary( ) anticlines up to 35 km wide. Southeast of Dixon Entrance, the active fault trace trends back onto the outer shelf until midway along the Queen Charlotte Islands, then cuts back to and stays at midslope to the Tuzo Wilson Knolls south of the Queen Charlotte Islands. The fault steps westward at Tuzo Wilson Knolls, which are likely part of a spreading ridge segment. Major deep-sea fans along southeast Alaska show a southeastward age progression from older to younger and record both point source deposition at Chatham Strait and Dixon Entrance and subsequent (Quaternary ) offset along the fault system. Subsidence of ocean plate now adjacent to the Chatham Strait-Dixon Entrance fault segment initiated development of both Mukluk and Horizon Channels.« less

Tutorial: Advanced fault tree applications using HARP

NASA Technical Reports Server (NTRS)

Dugan, Joanne Bechta; Bavuso, Salvatore J.; Boyd, Mark A.

1993-01-01

Reliability analysis of fault tolerant computer systems for critical applications is complicated by several factors. These modeling difficulties are discussed and dynamic fault tree modeling techniques for handling them are described and demonstrated. Several advanced fault tolerant computer systems are described, and fault tree models for their analysis are presented. HARP (Hybrid Automated Reliability Predictor) is a software package developed at Duke University and NASA Langley Research Center that is capable of solving the fault tree models presented.

InSAR analysis of the crustal deformation affecting the megacity of Istanbul: the results of the FP7 Marsite Project as a GEO Supersite Initiative

NASA Astrophysics Data System (ADS)

Solaro, Giuseppe; Bonano, Manuela; Manzo, Mariarosaria

2016-04-01

The North Anatolian Fault (NAF) is one of the most active faults worldwide, extending approximately 1,200 km from Eastern Turkey to the Northern Aegean Sea. During the 20th century series of damaging earthquakes occurred along the NAF, generally propagated westward towards Istanbul; the last one occurred in 1999 at Izmit, a city 80 km away from Istanbul. Within this scenario, the FP7 MARsite project (New Directions in Seismic Hazard assessment through Focused Earth Observation in Marmara Supersite), supported by EU, intends to collect, share and integrate multidisciplinary data (seismologic, geochemical, surveying, satellite, etc.) in order to carry out assessment, mitigation and management of seismic risk in the region of the Sea of Marmara. In the framework of the MARsite project, we performed the analysis and monitoring of the surface deformation affecting the Istanbul mega city by exploiting the large archives of X-band satellite SAR data, made available through the Supersites Initiatives, and by processing them via the advanced multi-temporal and multi-scale InSAR technique, known as the Small BAseline Subset (SBAS) approach. In particular, we applied the SBAS technique to a dataset of 101 SAR images acquired by the TerraSAR-X constellation of the German Space Agency (DLR) over descending orbits and spanning the November 2010 - August 2014 time interval. From,these images, we generated 312 differential interferograms with a maximum spatial separation (perpendicular baseline) between the acquisition orbits of about 500 m., that were used to generate, via the SBAS approach, mean deformation velocity map and corresponding ground time series of the investigated area. The performed InSAR analysis reveals a generalized stability over the Istanbul area, except for some localized displacements, related to subsidence and slope instability phenomena. In particular, we identified: (i) a displacement pattern related to the Istanbul airport, showing a mostly linear deformation trend with a velocity of about 1 cm/yr, although a slowdown effect is observed starting from early 2014, and (ii) a subsidence phenomenon in correspondence to Miniaturk park with a mean velocity value of about 1.5 cm/yr. Moreover, by benefiting from the recent launch of the C-band Sentinel-1A (S1A) satellite (April 2014), developed within the European Commission Copernicus Programme, we performed a more recent InSAR analysis of the Istanbul mega city and its surroundings by exploiting datasets collected during the October 2014 - December 2015 time interval. In such a way, we are able to investigate possible changes in the spatial and temporal deformation rates of the detected displacements over time with the aim to improve the comprehension of the deformation processes already occurred and/or occurring in this area. The obtained results, generated within the MARsite project, are expected to be available to scientific community through the Geohazards Exploitation Platform (GEP), an ESA platform aimed at supporting the exploitation of satellite EO data for geohazards, to be fully compliant with some of the major issues of the Supersites Initiative, as well as to foster the InSAR data sharing within a wider scientific community.

Fault Analysis in Solar Photovoltaic Arrays

NASA Astrophysics Data System (ADS)

Zhao, Ye

Fault analysis in solar photovoltaic (PV) arrays is a fundamental task to increase reliability, efficiency and safety in PV systems. Conventional fault protection methods usually add fuses or circuit breakers in series with PV components. But these protection devices are only able to clear faults and isolate faulty circuits if they carry a large fault current. However, this research shows that faults in PV arrays may not be cleared by fuses under some fault scenarios, due to the current-limiting nature and non-linear output characteristics of PV arrays. First, this thesis introduces new simulation and analytic models that are suitable for fault analysis in PV arrays. Based on the simulation environment, this thesis studies a variety of typical faults in PV arrays, such as ground faults, line-line faults, and mismatch faults. The effect of a maximum power point tracker on fault current is discussed and shown to, at times, prevent the fault current protection devices to trip. A small-scale experimental PV benchmark system has been developed in Northeastern University to further validate the simulation conclusions. Additionally, this thesis examines two types of unique faults found in a PV array that have not been studied in the literature. One is a fault that occurs under low irradiance condition. The other is a fault evolution in a PV array during night-to-day transition. Our simulation and experimental results show that overcurrent protection devices are unable to clear the fault under "low irradiance" and "night-to-day transition". However, the overcurrent protection devices may work properly when the same PV fault occurs in daylight. As a result, a fault under "low irradiance" and "night-to-day transition" might be hidden in the PV array and become a potential hazard for system efficiency and reliability.

Stress concentrations at structural discontinuities in active fault zones in the western United States: Implications for permeability and fluid flow in geothermal fields

USGS Publications Warehouse

Siler, Drew; Hinz, Nicholas H.; Faulds, James E.

2018-01-01

Slip can induce concentration of stresses at discontinuities along fault systems. These structural discontinuities, i.e., fault terminations, fault step-overs, intersections, bends, and other fault interaction areas, are known to host fluid flow in ore deposition systems, oil and gas reservoirs, and geothermal systems. We modeled stress transfer associated with slip on faults with Holocene-to-historic slip histories at the Salt Wells and Bradys geothermal systems in western Nevada, United States. Results show discrete locations of stress perturbation within discontinuities along these fault systems. Well field data, surface geothermal manifestations, and subsurface temperature data, each a proxy for modern fluid circulation in the fields, indicate that geothermal fluid flow is focused in these same areas where stresses are most highly perturbed. These results suggest that submeter- to meter-scale slip on these fault systems generates stress perturbations that are sufficiently large to promote slip on an array of secondary structures spanning the footprint of the modern geothermal activity. Slip on these secondary faults and fractures generates permeability through kinematic deformation and allows for transmission of fluids. Still, mineralization is expected to seal permeability along faults and fractures over time scales that are generally shorter than either earthquake recurrence intervals or the estimated life span of geothermal fields. This suggests that though stress perturbations resulting from fault slip are broadly important for defining the location and spatial extent of enhanced permeability at structural discontinuities, continual generation and maintenance of flow conduits throughout these areas are probably dependent on the deformation mechanism(s) affecting individual structures.

Adaptive robust fault-tolerant control for linear MIMO systems with unmatched uncertainties

NASA Astrophysics Data System (ADS)

Zhang, Kangkang; Jiang, Bin; Yan, Xing-Gang; Mao, Zehui

2017-10-01

In this paper, two novel fault-tolerant control design approaches are proposed for linear MIMO systems with actuator additive faults, multiplicative faults and unmatched uncertainties. For time-varying multiplicative and additive faults, new adaptive laws and additive compensation functions are proposed. A set of conditions is developed such that the unmatched uncertainties are compensated by actuators in control. On the other hand, for unmatched uncertainties with their projection in unmatched space being not zero, based on a (vector) relative degree condition, additive functions are designed to compensate for the uncertainties from output channels in the presence of actuator faults. The developed fault-tolerant control schemes are applied to two aircraft systems to demonstrate the efficiency of the proposed approaches.

Publications - PIR 2015-5-2 | Alaska Division of Geological & Geophysical

Science.gov Websites

faults in the Bruin Bay fault system, Ursus Head, lower Cook Inlet Authors: Betka, P.M., and Gillis, R.J strike-slip and reverse-slip faults in the Bruin Bay fault system, Ursus Head, lower Cook Inlet, in

Formal Validation of Fault Management Design Solutions

NASA Technical Reports Server (NTRS)

Gibson, Corrina; Karban, Robert; Andolfato, Luigi; Day, John

2013-01-01

The work presented in this paper describes an approach used to develop SysML modeling patterns to express the behavior of fault protection, test the model's logic by performing fault injection simulations, and verify the fault protection system's logical design via model checking. A representative example, using a subset of the fault protection design for the Soil Moisture Active-Passive (SMAP) system, was modeled with SysML State Machines and JavaScript as Action Language. The SysML model captures interactions between relevant system components and system behavior abstractions (mode managers, error monitors, fault protection engine, and devices/switches). Development of a method to implement verifiable and lightweight executable fault protection models enables future missions to have access to larger fault test domains and verifiable design patterns. A tool-chain to transform the SysML model to jpf-Statechart compliant Java code and then verify the generated code via model checking was established. Conclusions and lessons learned from this work are also described, as well as potential avenues for further research and development.

Identifiability of Additive, Time-Varying Actuator and Sensor Faults by State Augmentation

NASA Technical Reports Server (NTRS)

Upchurch, Jason M.; Gonzalez, Oscar R.; Joshi, Suresh M.

2014-01-01

Recent work has provided a set of necessary and sucient conditions for identifiability of additive step faults (e.g., lock-in-place actuator faults, constant bias in the sensors) using state augmentation. This paper extends these results to an important class of faults which may affect linear, time-invariant systems. In particular, the faults under consideration are those which vary with time and affect the system dynamics additively. Such faults may manifest themselves in aircraft as, for example, control surface oscillations, control surface runaway, and sensor drift. The set of necessary and sucient conditions presented in this paper are general, and apply when a class of time-varying faults affects arbitrary combinations of actuators and sensors. The results in the main theorems are illustrated by two case studies, which provide some insight into how the conditions may be used to check the theoretical identifiability of fault configurations of interest for a given system. It is shown that while state augmentation can be used to identify certain fault configurations, other fault configurations are theoretically impossible to identify using state augmentation, giving practitioners valuable insight into such situations. That is, the limitations of state augmentation for a given system and configuration of faults are made explicit. Another limitation of model-based methods is that there can be large numbers of fault configurations, thus making identification of all possible configurations impractical. However, the theoretical identifiability of known, credible fault configurations can be tested using the theorems presented in this paper, which can then assist the efforts of fault identification practitioners.

Designing Fault-Injection Experiments for the Reliability of Embedded Systems

NASA Technical Reports Server (NTRS)

White, Allan L.

2012-01-01

This paper considers the long-standing problem of conducting fault-injections experiments to establish the ultra-reliability of embedded systems. There have been extensive efforts in fault injection, and this paper offers a partial summary of the efforts, but these previous efforts have focused on realism and efficiency. Fault injections have been used to examine diagnostics and to test algorithms, but the literature does not contain any framework that says how to conduct fault-injection experiments to establish ultra-reliability. A solution to this problem integrates field-data, arguments-from-design, and fault-injection into a seamless whole. The solution in this paper is to derive a model reduction theorem for a class of semi-Markov models suitable for describing ultra-reliable embedded systems. The derivation shows that a tight upper bound on the probability of system failure can be obtained using only the means of system-recovery times, thus reducing the experimental effort to estimating a reasonable number of easily-observed parameters. The paper includes an example of a system subject to both permanent and transient faults. There is a discussion of integrating fault-injection with field-data and arguments-from-design.

Formal Techniques for Synchronized Fault-Tolerant Systems

NASA Technical Reports Server (NTRS)

DiVito, Ben L.; Butler, Ricky W.

1992-01-01

We present the formal verification of synchronizing aspects of the Reliable Computing Platform (RCP), a fault-tolerant computing system for digital flight control applications. The RCP uses NMR-style redundancy to mask faults and internal majority voting to purge the effects of transient faults. The system design has been formally specified and verified using the EHDM verification system. Our formalization is based on an extended state machine model incorporating snapshots of local processors clocks.

The Cottage Grove fault system (Illinois Basin): Late Paleozoic transpression along a Precambrian crustal boundary

USGS Publications Warehouse

Duchek, A.B.; McBride, J.H.; Nelson, W.J.; Leetaru, H.E.

2004-01-01

The Cottage Grove fault system in southern Illinois has long been interpreted as an intracratonic dextral strike-slip fault system. We investigated its structural geometry and kinematics in detail using (1) outcrop data, (2) extensive exposures in underground coal mines, (3) abundant borehole data, and (4) a network of industry seismic reflection profiles, including data reprocessed by us. Structural contour mapping delineates distinct monoclines, broad anticlines, and synclines that express Paleozoic-age deformation associated with strike slip along the fault system. As shown on seismic reflection profiles, prominent near-vertical faults that cut the entire Paleozoic section and basement-cover contact branch upward into outward-splaying, high-angle reverse faults. The master fault, sinuous along strike, is characterized along its length by an elongate anticline, ???3 km wide, that parallels the southern side of the master fault. These features signify that the overall kinematic regime was transpressional. Due to the absence of suitable piercing points, the amount of slip cannot be measured, but is constrained at less than 300 m near the ground surface. The Cottage Grove fault system apparently follows a Precambrian terrane boundary, as suggested by magnetic intensity data, the distribution of ultramafic igneous intrusions, and patterns of earthquake activity. The fault system was primarily active during the Alleghanian orogeny of Late Pennsylvanian and Early Permian time, when ultramatic igneous magma intruded along en echelon tensional fractures. ?? 2004 Geological Society of America.

Alaska Crustal Deformation: Finite Element Modeling Constrained by Geologic and Very Long Baseline Interferometry Data

NASA Technical Reports Server (NTRS)

Lundgren, Paul; Saucier, Fraancois; Palmer, Randy; Langon, Marc

1995-01-01

We compute crustal motions in Alaska by calculating the finite element solution for an elastic spherical shell problem. The method we use allows the finite element mesh to include faults and very long baseline interferometry (VLBI) baseline rates of change. Boundary conditions include Pacific-North American (PA-NA) plate motions. The solution is constrained by the oblique orientation of the Fairweather-Queen Charlotte strike-slip faults relative to the PA-NA relative motion direction and the oblique orientation from normal convergence of the eastern Aleutian trench fault systems, as well as strike-shp motion along the Denali and Totschunda fault systems. We explore the effects that a range of fault slip constraints and weighting of VLBI rates of change has on the solution. This allows us to test the motion on faults, such as the Denali fault, where there are conflicting reports on its present-day slip rate. We find a pattern of displacements which produce fault motions generally consistent with geologic observations. The motion of the continuum has the general pattern of radial movement of crust to the NE away from the Fairweather-Queen Charlotte fault systems in SE Alaska and Canada. This pattern of crustal motion is absorbed across the Mackenzie Mountains in NW Canada, with strike-slip motion constrained along the Denali and Tintina fault systems. In south central Alaska and the Alaska forearc oblique convergence at the eastern Aleutian trench and the strike-shp motion of the Denali fault system produce a counterclockwise pattern of motion which is partially absorbed along the Contact and related fault systems in southern Alaska and is partially extruded into the Bering Sea and into the forearc parallel the Aleutian trench from the Alaska Peninsula westward. Rates of motion and fault slip are small in western and northern Alaska, but the motions we compute are consistent with the senses of strike-slip motion inferred geologically along the Kaltag, Kobuk Trench, and Thompson Creek faults and with the normal faulting observed in NW Alaska near Nome. The nonrigid behavior of our finite element solution produces patterns of motion that would not have been expected from rigid block models: strike-slip faults can exist in a continuum that has motion mostly perpendicular to their strikes, and faults can exhibit along-strike differences in magnitudes and directions.

Method and system for environmentally adaptive fault tolerant computing

NASA Technical Reports Server (NTRS)

Copenhaver, Jason L. (Inventor); Jeremy, Ramos (Inventor); Wolfe, Jeffrey M. (Inventor); Brenner, Dean (Inventor)

2010-01-01

A method and system for adapting fault tolerant computing. The method includes the steps of measuring an environmental condition representative of an environment. An on-board processing system's sensitivity to the measured environmental condition is measured. It is determined whether to reconfigure a fault tolerance of the on-board processing system based in part on the measured environmental condition. The fault tolerance of the on-board processing system may be reconfigured based in part on the measured environmental condition.

A Solid-State Fault Current Limiting Device for VSC-HVDC Systems

NASA Astrophysics Data System (ADS)

Larruskain, D. Marene; Zamora, Inmaculada; Abarrategui, , Oihane; Iturregi, Araitz

2013-08-01

Faults in the DC circuit constitute one of the main limitations of voltage source converter VSC-HVDC systems, as the high fault currents can damage seriously the converters. In this article, a new design for a fault current limiter (FCL) is proposed, which is capable of limiting the fault current as well as interrupting it, isolating the DC grid. The operation of the proposed FCL is analysed and verified with the most usual faults that can occur in overhead lines.

Graph-based real-time fault diagnostics

NASA Technical Reports Server (NTRS)

Padalkar, S.; Karsai, G.; Sztipanovits, J.

1988-01-01

A real-time fault detection and diagnosis capability is absolutely crucial in the design of large-scale space systems. Some of the existing AI-based fault diagnostic techniques like expert systems and qualitative modelling are frequently ill-suited for this purpose. Expert systems are often inadequately structured, difficult to validate and suffer from knowledge acquisition bottlenecks. Qualitative modelling techniques sometimes generate a large number of failure source alternatives, thus hampering speedy diagnosis. In this paper we present a graph-based technique which is well suited for real-time fault diagnosis, structured knowledge representation and acquisition and testing and validation. A Hierarchical Fault Model of the system to be diagnosed is developed. At each level of hierarchy, there exist fault propagation digraphs denoting causal relations between failure modes of subsystems. The edges of such a digraph are weighted with fault propagation time intervals. Efficient and restartable graph algorithms are used for on-line speedy identification of failure source components.

The emergence of asymmetric normal fault systems under symmetric boundary conditions

NASA Astrophysics Data System (ADS)

Schöpfer, Martin P. J.; Childs, Conrad; Manzocchi, Tom; Walsh, John J.; Nicol, Andrew; Grasemann, Bernhard

2017-11-01

Many normal fault systems and, on a smaller scale, fracture boudinage often exhibit asymmetry with one fault dip direction dominating. It is a common belief that the formation of domino and shear band boudinage with a monoclinic symmetry requires a component of layer parallel shearing. Moreover, domains of parallel faults are frequently used to infer the presence of a décollement. Using Distinct Element Method (DEM) modelling we show, that asymmetric fault systems can emerge under symmetric boundary conditions. A statistical analysis of DEM models suggests that the fault dip directions and system polarities can be explained using a random process if the strength contrast between the brittle layer and the surrounding material is high. The models indicate that domino and shear band boudinage are unreliable shear-sense indicators. Moreover, the presence of a décollement should not be inferred on the basis of a domain of parallel faults alone.

Indirect adaptive fuzzy fault-tolerant tracking control for MIMO nonlinear systems with actuator and sensor failures.

PubMed

Bounemeur, Abdelhamid; Chemachema, Mohamed; Essounbouli, Najib

2018-05-10

In this paper, an active fuzzy fault tolerant tracking control (AFFTTC) scheme is developed for a class of multi-input multi-output (MIMO) unknown nonlinear systems in the presence of unknown actuator faults, sensor failures and external disturbance. The developed control scheme deals with four kinds of faults for both sensors and actuators. The bias, drift, and loss of accuracy additive faults are considered along with the loss of effectiveness multiplicative fault. A fuzzy adaptive controller based on back-stepping design is developed to deal with actuator failures and unknown system dynamics. However, an additional robust control term is added to deal with sensor faults, approximation errors, and external disturbances. Lyapunov theory is used to prove the stability of the closed loop system. Numerical simulations on a quadrotor are presented to show the effectiveness of the proposed approach. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Model-based development of a fault signature matrix to improve solid oxide fuel cell systems on-site diagnosis

NASA Astrophysics Data System (ADS)

Polverino, Pierpaolo; Pianese, Cesare; Sorrentino, Marco; Marra, Dario

2015-04-01

The paper focuses on the design of a procedure for the development of an on-field diagnostic algorithm for solid oxide fuel cell (SOFC) systems. The diagnosis design phase relies on an in-deep analysis of the mutual interactions among all system components by exploiting the physical knowledge of the SOFC system as a whole. This phase consists of the Fault Tree Analysis (FTA), which identifies the correlations among possible faults and their corresponding symptoms at system components level. The main outcome of the FTA is an inferential isolation tool (Fault Signature Matrix - FSM), which univocally links the faults to the symptoms detected during the system monitoring. In this work the FTA is considered as a starting point to develop an improved FSM. Making use of a model-based investigation, a fault-to-symptoms dependency study is performed. To this purpose a dynamic model, previously developed by the authors, is exploited to simulate the system under faulty conditions. Five faults are simulated, one for the stack and four occurring at BOP level. Moreover, the robustness of the FSM design is increased by exploiting symptom thresholds defined for the investigation of the quantitative effects of the simulated faults on the affected variables.

Research on Fault Characteristics and Line Protections Within a Large-scale Photovoltaic Power Plant

NASA Astrophysics Data System (ADS)

Zhang, Chi; Zeng, Jie; Zhao, Wei; Zhong, Guobin; Xu, Qi; Luo, Pandian; Gu, Chenjie; Liu, Bohan

2017-05-01

Centralized photovoltaic (PV) systems have different fault characteristics from distributed PV systems due to the different system structures and controls. This makes the fault analysis and protection methods used in distribution networks with distributed PV not suitable for a centralized PV power plant. Therefore, a consolidated expression for the fault current within a PV power plant under different controls was calculated considering the fault response of the PV array. Then, supported by the fault current analysis and the on-site testing data, the overcurrent relay (OCR) performance was evaluated in the collection system of an 850 MW PV power plant. It reveals that the OCRs at downstream side on overhead lines may malfunction. In this case, a new relay scheme was proposed using directional distance elements. In the PSCAD/EMTDC, a detailed PV system model was built and verified using the on-site testing data. Simulation results indicate that the proposed relay scheme could effectively solve the problems under variant fault scenarios and PV plant output levels.

Evidence of Quaternary and recent activity along the Kyaukkyan Fault, Myanmar

NASA Astrophysics Data System (ADS)

Crosetto, Silvia; Watkinson, Ian M.; Soe Min; Gori, Stefano; Falcucci, Emanuela; Nwai Le Ngal

2018-05-01

Cenozoic right-lateral shear between the eastern Indian margin and Eurasia is expressed by numerous N-S trending fault systems inboard of the Sunda trench, including the Sagaing Fault. The most easterly of these fault systems is the prominent ∼500 km long Kyaukkyan Fault, on the Shan Plateau. Myanmar's largest recorded earthquake, Mw 7.7 on 23rd May 1912, focused near Maymyo, has been attributed to the Kyaukkyan Fault, but the area has experienced little significant seismicity since then. Despite its demonstrated seismic potential and remarkable topographic expression, questions remain about the Kyaukkyan Fault's neotectonic history.

A distributed fault-tolerant signal processor /FTSP/

NASA Astrophysics Data System (ADS)

Bonneau, R. J.; Evett, R. C.; Young, M. J.

1980-01-01

A digital fault-tolerant signal processor (FTSP), an example of a self-repairing programmable system is analyzed. The design configuration is discussed in terms of fault tolerance, system-level fault detection, isolation and common memory. Special attention is given to the FDIR (fault detection isolation and reconfiguration) logic, noting that the reconfiguration decisions are based on configuration, summary status, end-around tests, and north marker/synchro data. Several mechanisms of fault detection are described which initiate reconfiguration at different levels. It is concluded that the reliability of a signal processor can be significantly enhanced by the use of fault-tolerant techniques.

Advanced power system protection and incipient fault detection and protection of spaceborne power systems

NASA Technical Reports Server (NTRS)

Russell, B. Don

1989-01-01

This research concentrated on the application of advanced signal processing, expert system, and digital technologies for the detection and control of low grade, incipient faults on spaceborne power systems. The researchers have considerable experience in the application of advanced digital technologies and the protection of terrestrial power systems. This experience was used in the current contracts to develop new approaches for protecting the electrical distribution system in spaceborne applications. The project was divided into three distinct areas: (1) investigate the applicability of fault detection algorithms developed for terrestrial power systems to the detection of faults in spaceborne systems; (2) investigate the digital hardware and architectures required to monitor and control spaceborne power systems with full capability to implement new detection and diagnostic algorithms; and (3) develop a real-time expert operating system for implementing diagnostic and protection algorithms. Significant progress has been made in each of the above areas. Several terrestrial fault detection algorithms were modified to better adapt to spaceborne power system environments. Several digital architectures were developed and evaluated in light of the fault detection algorithms.

On-board fault management for autonomous spacecraft

NASA Technical Reports Server (NTRS)

Fesq, Lorraine M.; Stephan, Amy; Doyle, Susan C.; Martin, Eric; Sellers, Suzanne

1991-01-01

The dynamic nature of the Cargo Transfer Vehicle's (CTV) mission and the high level of autonomy required mandate a complete fault management system capable of operating under uncertain conditions. Such a fault management system must take into account the current mission phase and the environment (including the target vehicle), as well as the CTV's state of health. This level of capability is beyond the scope of current on-board fault management systems. This presentation will discuss work in progress at TRW to apply artificial intelligence to the problem of on-board fault management. The goal of this work is to develop fault management systems. This presentation will discuss work in progress at TRW to apply artificial intelligence to the problem of on-board fault management. The goal of this work is to develop fault management systems that can meet the needs of spacecraft that have long-range autonomy requirements. We have implemented a model-based approach to fault detection and isolation that does not require explicit characterization of failures prior to launch. It is thus able to detect failures that were not considered in the failure and effects analysis. We have applied this technique to several different subsystems and tested our approach against both simulations and an electrical power system hardware testbed. We present findings from simulation and hardware tests which demonstrate the ability of our model-based system to detect and isolate failures, and describe our work in porting the Ada version of this system to a flight-qualified processor. We also discuss current research aimed at expanding our system to monitor the entire spacecraft.

Early Tertiary transtension-related deformation and magmatism along the Tintina fault system, Alaska

USGS Publications Warehouse

Till, A.B.; Roeske, S.M.; Bradley, D.C.; Friedman, R.; Layer, P.W.

2007-01-01

Transtensional deformation was concentrated in a zone adjacent to the Tintina strike-slip fault system in Alaska during the early Tertiary. The deformation occurred along the Victoria Creek fault, the trace of the Tintina system that connects it with the Kaltag fault; together the Tintina and Kaltag fault systems girdle Alaska from east to west. Over an area of ???25 by 70 km between the Victoria Creek and Tozitna faults, bimodal volcanics erupted; lacustrine and fluvial rocks were deposited; plutons were emplaced and deformed; and metamorphic rocks cooled, all at about the same time. Plutonic and volcanic rocks in this zone yield U-Pb zircon ages of ca. 60 Ma; 40Ar/ 39Ar cooling ages from those plutons and adjacent metamorphic rocks are also ca. 60 Ma. Although early Tertiary magmatism occurred over a broad area in central Alaska, meta- morphism and ductile deformation accompanied that magmatism in this one zone only. Within the zone of deformation, pluton aureoles and metamorphic rocks display consistent NE-SW-stretching lineations parallel to the Victoria Creek fault, suggesting that deformation processes involved subhorizontal elongation of the package. The most deeply buried metamorphic rocks, kyanite-bearing metapelites, occur as lenses adjacent to the fault, which cuts the crust to the Moho (Beaudoin et al., 1997). Geochronologic data and field relationships suggest that the amount of early Tertiary exhumation was greatest adjacent to the Victoria Creek fault. The early Tertiary crustal-scale events that may have operated to produce transtension in this area are (1) increased heat flux and related bimodal within-plate magmatism, (2) movement on a releasing stepover within the Tintina fault system or on a regional scale involving both the Tintina and the Kobuk fault systems, and (3) oroclinal bending of the Tintina-Kaltag fault system with counterclockwise rotation of western Alaska. ?? 2007 The Geological Society of America. All rights reserved.

Robust fault detection of wind energy conversion systems based on dynamic neural networks.

PubMed

Talebi, Nasser; Sadrnia, Mohammad Ali; Darabi, Ahmad

2014-01-01

Occurrence of faults in wind energy conversion systems (WECSs) is inevitable. In order to detect the occurred faults at the appropriate time, avoid heavy economic losses, ensure safe system operation, prevent damage to adjacent relevant systems, and facilitate timely repair of failed components; a fault detection system (FDS) is required. Recurrent neural networks (RNNs) have gained a noticeable position in FDSs and they have been widely used for modeling of complex dynamical systems. One method for designing an FDS is to prepare a dynamic neural model emulating the normal system behavior. By comparing the outputs of the real system and neural model, incidence of the faults can be identified. In this paper, by utilizing a comprehensive dynamic model which contains both mechanical and electrical components of the WECS, an FDS is suggested using dynamic RNNs. The presented FDS detects faults of the generator's angular velocity sensor, pitch angle sensors, and pitch actuators. Robustness of the FDS is achieved by employing an adaptive threshold. Simulation results show that the proposed scheme is capable to detect the faults shortly and it has very low false and missed alarms rate.

Robust Fault Detection of Wind Energy Conversion Systems Based on Dynamic Neural Networks

PubMed Central

Talebi, Nasser; Sadrnia, Mohammad Ali; Darabi, Ahmad

2014-01-01

Occurrence of faults in wind energy conversion systems (WECSs) is inevitable. In order to detect the occurred faults at the appropriate time, avoid heavy economic losses, ensure safe system operation, prevent damage to adjacent relevant systems, and facilitate timely repair of failed components; a fault detection system (FDS) is required. Recurrent neural networks (RNNs) have gained a noticeable position in FDSs and they have been widely used for modeling of complex dynamical systems. One method for designing an FDS is to prepare a dynamic neural model emulating the normal system behavior. By comparing the outputs of the real system and neural model, incidence of the faults can be identified. In this paper, by utilizing a comprehensive dynamic model which contains both mechanical and electrical components of the WECS, an FDS is suggested using dynamic RNNs. The presented FDS detects faults of the generator's angular velocity sensor, pitch angle sensors, and pitch actuators. Robustness of the FDS is achieved by employing an adaptive threshold. Simulation results show that the proposed scheme is capable to detect the faults shortly and it has very low false and missed alarms rate. PMID:24744774

Quasi-dynamic earthquake fault systems with rheological heterogeneity

NASA Astrophysics Data System (ADS)

Brietzke, G. B.; Hainzl, S.; Zoeller, G.; Holschneider, M.

2009-12-01

Seismic risk and hazard estimates mostly use pure empirical, stochastic models of earthquake fault systems tuned specifically to the vulnerable areas of interest. Although such models allow for reasonable risk estimates, such models cannot allow for physical statements of the described seismicity. In contrary such empirical stochastic models, physics based earthquake fault systems models allow for a physical reasoning and interpretation of the produced seismicity and system dynamics. Recently different fault system earthquake simulators based on frictional stick-slip behavior have been used to study effects of stress heterogeneity, rheological heterogeneity, or geometrical complexity on earthquake occurrence, spatial and temporal clustering of earthquakes, and system dynamics. Here we present a comparison of characteristics of synthetic earthquake catalogs produced by two different formulations of quasi-dynamic fault system earthquake simulators. Both models are based on discretized frictional faults embedded in an elastic half-space. While one (1) is governed by rate- and state-dependent friction with allowing three evolutionary stages of independent fault patches, the other (2) is governed by instantaneous frictional weakening with scheduled (and therefore causal) stress transfer. We analyze spatial and temporal clustering of events and characteristics of system dynamics by means of physical parameters of the two approaches.

Preparation of Synthetic Earthquake Catalogue and Tsunami Hazard Curves in Marmara Sea using Monte Carlo Simulations

NASA Astrophysics Data System (ADS)

Bayraktar, Başak; Özer Sözdinler, Ceren; Necmioǧlu, Öcal; Meral Özel, Nurcan

2017-04-01

The Marmara Sea and its surrounding is one of the most populated areas in Turkey. Many densely populated cities, such as megacity Istanbul with a population of more than 14 million, a great number of industrial facilities in largest capacity and potential, refineries, ports and harbors are located along the coasts of Marmara Sea. The region is highly seismically active. There has been a wide range of studies in this region regarding the fault mechanisms, seismic activities, earthquakes and triggered tsunamis in the Sea of Marmara. The historical documents reveal that the region has been experienced many earthquakes and tsunamis in the past. According to Altinok et al. (2011), 35 tsunami events happened in Marmara Sea between BC 330 and 1999. As earthquakes are expected in Marmara Sea with the break of segments of North Anatolian Fault (NAF) in the future, the region should be investigated in terms of the possibility of tsunamis by the occurrence of earthquakes in specific return periods. This study aims to make probabilistic tsunami hazard analysis in Marmara Sea. For this purpose, the possible sources of tsunami scenarios are specified by compiling the earthquake catalogues, historical records and scientific studies conducted in the region. After compiling all this data, a synthetic earthquake and tsunami catalogue are prepared using Monte Carlo simulations. For specific return periods, the possible epicenters, rupture lengths, widths and displacements are determined with Monte Carlo simulations assuming the angles of fault segments as deterministic. For each earthquake of synthetic catalogue, the tsunami wave heights will be calculated at specific locations along Marmara Sea. As a further objective, this study will determine the tsunami hazard curves for specific locations in Marmara Sea including the tsunami wave heights and their probability of exceedance. This work is supported by SATREPS-MarDim Project (Earthquake and Tsunami Disaster Mitigation in the Marmara Region and Disaster Education in Turkey) and JICA (Japan International Cooperation Agency). The authors would like to acknowledge the project MARsite - New Directions in Seismic Hazard assessment through Focused Earth Observation in the Marmara Supersite (FP7-ENV.2012 6.4-2, Grant 308417 - see NH2.3/GMPV7.4/SM7.7). The authors also would like to acknowledge Prof. Dr. Mustafa Erdik and Prof. Dr. Sinan Akkar for their valuable feedback and guidance throughout this study.

Fragipan Horizon Fragmentation in Slaking Experiments with Amendment Materials and Ryegrass Root Tissue Extracts

PubMed Central

Karathanasis, A. D.; Murdock, L. W.; Matocha, C. J.; Grove, J.; Thompson, Y. L.

2014-01-01

Slaking experiments were conducted of fragipan clods immersed in solutions of poultry manure, aerobically digested biosolid waste (ADB), fluidized bed combustion byproduct (FBC), D-H2O, CaCO3, NaF, Na-hexa-metaphosphate, and ryegrass root biomass. The fragipan clods were sampled from the Btx horizon of an Oxyaquic Fragiudalf in Kentucky. Wet sieving aggregate analysis showed significantly better fragmentation in the NaF, Na-hexa-metaphosphate, and ryegrass root solutions with a mean weight diameter range of 15.5–18.8 mm compared to the 44.2–47.9 mm of the poultry manure, ADB, and FBC treatments. Dissolved Si, Al, Fe, and Mn levels released in solution were ambiguous. The poor efficiency of the poultry manure, ADB, and FBC treatments was attributed to their high ionic strength, while the high efficiency of the NaF, Na-hexa-metaphosphate, and rye grass root solutions to their high sodium soluble ratio (SSR). A slaking mechanism is proposed suggesting that aqueous solutions with high SSR penetrate faster into the fragipan capillaries and generate the critical swelling pressure and shearing stress required to rupture the fragipan into several fragments. Additional fragmentation occurs in a followup stage during which potential Si, Al, Fe, and Mn binding agents may be released into solution. Field experiments testing these findings are in progress. PMID:25254233

Corrosive effects of fluoride on titanium: investigation by X-ray photoelectron spectroscopy, atomic force microscopy, and human epithelial cell culturing.

PubMed

Stájer, Anette; Ungvári, Krisztina; Pelsoczi, István K; Polyánka, Hilda; Oszkó, Albert; Mihalik, Erzsébet; Rakonczay, Zoltán; Radnai, Márta; Kemény, Lajos; Fazekas, András; Turzó, Kinga

2008-11-01

High fluoride (F(-)) concentrations and acidic pH impair the corrosion resistance of titanium (Ti). Effects of F(-)-containing caries-preventive prophylactic rinses, and gels on Ti were investigated by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Human epithelial cell attachment and proliferation were investigated by dimethylthiazol-diphenyl tetrazolium bromide (MTT) and protein content assays. Aqueous 1% NaF solution (3800 ppm F(-), pH 4.5) or high (12,500 ppm) F(-) content gel (pH 4.8) strongly corroded the surface and modified its composition. XPS revealed formation of a strongly bound F(-)-containing complex (Na(2)TiF(6)). AFM indicated an increase in roughness (R(a)) of the surfaces: 10-fold for the NaF solution and smaller for the gel or a mouthwash (250 ppm F(-), pH 4.4). MTT revealed that cell attachment was significantly increased by the gel, but was not disturbed by either the mouthwash or the NaF. Cell proliferation determined by MTT decreased significantly only for the NaF-treated samples; protein content assay experiments showed no such effect. This study indicates that epithelial cell culturing results can depend on the method used, and the adverse effects of a high F(-) concentration and low pH should be considered when prophylactic gels are applied by patients with Ti implants or other dental devices.

Phylogenetic analysis of eukaryotic NEET proteins uncovers a link between a key gene duplication event and the evolution of vertebrates.

PubMed

Inupakutika, Madhuri A; Sengupta, Soham; Nechushtai, Rachel; Jennings, Patricia A; Onuchic, Jose' N; Azad, Rajeev K; Padilla, Pamela; Mittler, Ron

2017-02-16

NEET proteins belong to a unique family of iron-sulfur proteins in which the 2Fe-2S cluster is coordinated by a CDGSH domain that is followed by the "NEET" motif. They are involved in the regulation of iron and reactive oxygen metabolism, and have been associated with the progression of diabetes, cancer, aging and neurodegenerative diseases. Despite their important biological functions, the evolution and diversification of eukaryotic NEET proteins are largely unknown. Here we used the three members of the human NEET protein family (CISD1, mitoNEET; CISD2, NAF-1 or Miner 1; and CISD3, Miner2) as our guides to conduct a phylogenetic analysis of eukaryotic NEET proteins and their evolution. Our findings identified the slime mold Dictyostelium discoideum's CISD proteins as the closest to the ancient archetype of eukaryotic NEET proteins. We further identified CISD3 homologs in fungi that were previously reported not to contain any NEET proteins, and revealed that plants lack homolog(s) of CISD3. Furthermore, our study suggests that the mammalian NEET proteins, mitoNEET (CISD1) and NAF-1 (CISD2), emerged via gene duplication around the origin of vertebrates. Our findings provide new insights into the classification and expansion of the NEET protein family, as well as offer clues to the diverged functions of the human mitoNEET and NAF-1 proteins.

Extent and architecture of major fault systems between northern Victoria Land and the eastern margin of the Wilkes Subglacial Basin (East Antarctica)

NASA Astrophysics Data System (ADS)

Armadillo, E.; Ferraccioli, F.; Balbi, P.; Bozzo, E.

2013-12-01

Terrane bounding and intra-terrane faults of the Ross Orogen in East Antarctica are linked to several phases of Cambrian to Ordovician age subduction and accretion along the active paleo-Pacific margin of Gondwana. Here we compile and analyse new enhanced aeromagnetic anomaly images over the Northern Victoria Land (NVL) segment of the Ross Orogen and the eastern margin of the Wilkes Subglacial Basin (WSB) that help constrain the extent and structural architecture of these fault systems and enable us re-assess their tectonic evolution. Long-wavelength magnetic lows and residual Bouguer gravity highs are modelled as several-km thick inverted sedimentary basins of early Cambrian(?) age. Tectonic inversion occurred along major thrust faults during the late stages of the Ross Orogen, forming a major high-grade pop-up structure within the central Wilson Terrane, flanked by lower grade rocks. The Prince Albert Fault System can now be recongnised as being located to the west of the Exiles Thrust fault system rather than representing its southern continuation. Relatively thin sheets of mylonitic sheared granitoids and possible ultramafic lenses are associated with the late-Ross (ca 480 Ma) Exiles Thrust fault system, while significantly larger and thicker batholiths were emplaced along the Prince Albert Fault System. Recent zircon U-Pb dating over small exposures of gabbro-diorites within the Prince Albert Mountains to the south lead us to propose that this part of the magmatic arc was emplaced during an earlier phase of subduction (~520 Ma or older?), compared to the late-Ross intrusions to the east. Whether the Prince Albert Fault System was indeed a major cryptic suture in early Cambrian times (Ferraccioli et al., 2002, GRL) remains speculative, but possible. Our aeromagnetic interpretation leads us to conclude that these inherited terrane bounding and intra-terrane fault systems of the Ross Orogen exerted a key influence on Cenozoic tectonic blocks and faults of the Transantarctic Mountains, and that the eastern margin of the WSB adjacent to NVL was also strongly controlled by a complex array of major intraplate strike-slip fault systems.

Multi-faults decoupling on turbo-expander using differential-based ensemble empirical mode decomposition

NASA Astrophysics Data System (ADS)

Li, Hongguang; Li, Ming; Li, Cheng; Li, Fucai; Meng, Guang

2017-09-01

This paper dedicates on the multi-faults decoupling of turbo-expander rotor system using Differential-based Ensemble Empirical Mode Decomposition (DEEMD). DEEMD is an improved version of DEMD to resolve the imperfection of mode mixing. The nonlinear behaviors of the turbo-expander considering temperature gradient with crack, rub-impact and pedestal looseness faults are investigated respectively, so that the baseline for the multi-faults decoupling can be established. DEEMD is then utilized on the vibration signals of the rotor system with coupling faults acquired by numerical simulation, and the results indicate that DEEMD can successfully decouple the coupling faults, which is more efficient than EEMD. DEEMD is also applied on the vibration signal of the misalignment coupling with rub-impact fault obtained during the adjustment of the experimental system. The conclusion shows that DEEMD can decompose the practical multi-faults signal and the industrial prospect of DEEMD is verified as well.

Wavelet Based Protection Scheme for Multi Terminal Transmission System with PV and Wind Generation

NASA Astrophysics Data System (ADS)

Manju Sree, Y.; Goli, Ravi kumar; Ramaiah, V.

2017-08-01

A hybrid generation is a part of large power system in which number of sources usually attached to a power electronic converter and loads are clustered can operate independent of the main power system. The protection scheme is crucial against faults based on traditional over current protection since there are adequate problems due to fault currents in the mode of operation. This paper adopts a new approach for detection, discrimination of the faults for multi terminal transmission line protection in presence of hybrid generation. Transient current based protection scheme is developed with discrete wavelet transform. Fault indices of all phase currents at all terminals are obtained by analyzing the detail coefficients of current signals using bior 1.5 mother wavelet. This scheme is tested for different types of faults and is found effective for detection and discrimination of fault with various fault inception angle and fault impedance.

Functional requirements for an intelligent RPC. [remote power controller for spaceborne electrical distribution system

NASA Technical Reports Server (NTRS)

Aucoin, B. M.; Heller, R. P.

1990-01-01

An intelligent remote power controller (RPC) based on microcomputer technology can implement advanced functions for the accurate and secure detection of all types of faults on a spaceborne electrical distribution system. The intelligent RPC will implement conventional protection functions such as overcurrent, under-voltage, and ground fault protection. Advanced functions for the detection of soft faults, which cannot presently be detected, can also be implemented. Adaptive overcurrent protection changes overcurrent settings based on connected load. Incipient and high-impedance fault detection provides early detection of arcing conditions to prevent fires, and to clear and reconfigure circuits before soft faults progress to a hard-fault condition. Power electronics techniques can be used to implement fault current limiting to prevent voltage dips during hard faults. It is concluded that these techniques will enhance the overall safety and reliability of the distribution system.

Investigating Crustal Scale Fault Systems Controlling Volcanic and Hydrothermal Fluid Processes in the South-Central Andes, First Results from a Magnetotelluric Survey

NASA Astrophysics Data System (ADS)

Pearce, R.; Mitchell, T. M.; Moorkamp, M.; Araya, J.; Cembrano, J. M.; Yanez, G. A.; Hammond, J. O. S.

2017-12-01

At convergent plate boundaries, volcanic orogeny is largely controlled by major thrust fault systems that act as magmatic and hydrothermal fluid conduits through the crust. In the south-central Andes, the volcanically and seismically active Tinguiririca and Planchon-Peteroa volcanoes are considered to be tectonically related to the major El Fierro thrust fault system. These large scale reverse faults are characterized by 500 - 1000m wide hydrothermally altered fault cores, which possess a distinct conductive signature relative to surrounding lithology. In order to establish the subsurface architecture of these fault systems, such conductivity contrasts can be detected using the magnetotelluric method. In this study, LEMI fluxgate-magnetometer long-period and Metronix broadband MT data were collected at 21 sites in a 40km2 survey grid that surrounds this fault system and associated volcanic complexes. Multi-remote referencing techniques is used together with robust processing to obtain reliable impedance estimates between 100 Hz and 1,000s. Our preliminary inversion results provide evidence of structures within the 10 - 20 km depth range that are attributed to this fault system. Further inversions will be conducted to determine the approximate depth extent of these features, and ultimately provide constraints for future geophysical studies aimed to deduce the role of these faults in volcanic orogeny and hydrothermal fluid migration processes in this region of the Andes.

Software fault tolerance for real-time avionics systems

NASA Technical Reports Server (NTRS)

Anderson, T.; Knight, J. C.

1983-01-01

Avionics systems have very high reliability requirements and are therefore prime candidates for the inclusion of fault tolerance techniques. In order to provide tolerance to software faults, some form of state restoration is usually advocated as a means of recovery. State restoration can be very expensive for systems which utilize concurrent processes. The concurrency present in most avionics systems and the further difficulties introduced by timing constraints imply that providing tolerance for software faults may be inordinately expensive or complex. A straightforward pragmatic approach to software fault tolerance which is believed to be applicable to many real-time avionics systems is proposed. A classification system for software errors is presented together with approaches to recovery and continued service for each error type.

Airborne Advanced Reconfigurable Computer System (ARCS)

NASA Technical Reports Server (NTRS)

Bjurman, B. E.; Jenkins, G. M.; Masreliez, C. J.; Mcclellan, K. L.; Templeman, J. E.

1976-01-01

A digital computer subsystem fault-tolerant concept was defined, and the potential benefits and costs of such a subsystem were assessed when used as the central element of a new transport's flight control system. The derived advanced reconfigurable computer system (ARCS) is a triple-redundant computer subsystem that automatically reconfigures, under multiple fault conditions, from triplex to duplex to simplex operation, with redundancy recovery if the fault condition is transient. The study included criteria development covering factors at the aircraft's operation level that would influence the design of a fault-tolerant system for commercial airline use. A new reliability analysis tool was developed for evaluating redundant, fault-tolerant system availability and survivability; and a stringent digital system software design methodology was used to achieve design/implementation visibility.

Intelligent classifier for dynamic fault patterns based on hidden Markov model

NASA Astrophysics Data System (ADS)

Xu, Bo; Feng, Yuguang; Yu, Jinsong

2006-11-01

It's difficult to build precise mathematical models for complex engineering systems because of the complexity of the structure and dynamics characteristics. Intelligent fault diagnosis introduces artificial intelligence and works in a different way without building the analytical mathematical model of a diagnostic object, so it's a practical approach to solve diagnostic problems of complex systems. This paper presents an intelligent fault diagnosis method, an integrated fault-pattern classifier based on Hidden Markov Model (HMM). This classifier consists of dynamic time warping (DTW) algorithm, self-organizing feature mapping (SOFM) network and Hidden Markov Model. First, after dynamic observation vector in measuring space is processed by DTW, the error vector including the fault feature of being tested system is obtained. Then a SOFM network is used as a feature extractor and vector quantization processor. Finally, fault diagnosis is realized by fault patterns classifying with the Hidden Markov Model classifier. The importing of dynamic time warping solves the problem of feature extracting from dynamic process vectors of complex system such as aeroengine, and makes it come true to diagnose complex system by utilizing dynamic process information. Simulating experiments show that the diagnosis model is easy to extend, and the fault pattern classifier is efficient and is convenient to the detecting and diagnosing of new faults.

Fault Deformation and Segmentation of the Newport-Inglewood Rose Canyon, and San Onofre Trend Fault Systems from New High-Resolution 3D Seismic Imagery

NASA Astrophysics Data System (ADS)

Holmes, J. J.; Driscoll, N. W.; Kent, G. M.

2016-12-01

The Inner California Borderlands (ICB) is situated off the coast of southern California and northern Baja. The structural and geomorphic characteristics of the area record a middle Oligocene transition from subduction to microplate capture along the California coast. Marine stratigraphic evidence shows large-scale extension and rotation overprinted by modern strike-slip deformation. Geodetic and geologic observations indicate that approximately 6-8 mm/yr of Pacific-North American relative plate motion is accommodated by offshore strike-slip faulting in the ICB. The farthest inshore fault system, the Newport-Inglewood Rose Canyon (NIRC) Fault is a dextral strike-slip system that is primarily offshore for approximately 120 km from San Diego to the San Joaquin Hills near Newport Beach, California. Based on trenching and well data, the NIRC Fault Holocene slip rate is 1.5-2.0 mm/yr to the south and 0.5-1.0 mm/yr along its northern extent. An earthquake rupturing the entire length of the system could produce an Mw 7.0 earthquake or larger. West of the main segments of the NIRC Fault is the San Onofre Trend (SOT) along the continental slope. Previous work concluded that this is part of a strike-slip system that eventually merges with the NIRC Fault. Others have interpreted this system as deformation associated with the Oceanside Blind Thrust fault purported to underlie most of the region. In late 2013, we acquired the first high-resolution 3D Parallel Cable (P-Cable) seismic surveys of the NIRC and SOT faults as part of the Southern California Regional Fault Mapping project aboard the R/V New Horizon. Analysis of these data volumes provides important new insights and constraints on the fault segmentation and transfer of deformation. Based on this new data, we've mapped several small fault strands associated with the SOT that appear to link up with a westward jog in right-lateral fault splays of the NIRC Fault on the shelf and then narrowly radiate southwards. Our observations are that these strands are strike-slip features associated with a dying splay of the NIRC system rather than compressional features associated with a regional thrust.

Sliding Mode Fault Tolerant Control with Adaptive Diagnosis for Aircraft Engines

NASA Astrophysics Data System (ADS)

Xiao, Lingfei; Du, Yanbin; Hu, Jixiang; Jiang, Bin

2018-03-01

In this paper, a novel sliding mode fault tolerant control method is presented for aircraft engine systems with uncertainties and disturbances on the basis of adaptive diagnostic observer. By taking both sensors faults and actuators faults into account, the general model of aircraft engine control systems which is subjected to uncertainties and disturbances, is considered. Then, the corresponding augmented dynamic model is established in order to facilitate the fault diagnosis and fault tolerant controller design. Next, a suitable detection observer is designed to detect the faults effectively. Through creating an adaptive diagnostic observer and based on sliding mode strategy, the sliding mode fault tolerant controller is constructed. Robust stabilization is discussed and the closed-loop system can be stabilized robustly. It is also proven that the adaptive diagnostic observer output errors and the estimations of faults converge to a set exponentially, and the converge rate greater than some value which can be adjusted by choosing designable parameters properly. The simulation on a twin-shaft aircraft engine verifies the applicability of the proposed fault tolerant control method.

Geometric-kinematic characteristics of the main faults in the W-SW of the Lut Block (SE Iran)

NASA Astrophysics Data System (ADS)

Rashidi Boshrabadi, Ahmad; Khatib, Mohamad Mahdi; Raeesi, Mohamad; Mousavi, Seyed Morteza; Djamour, Yahya

2018-03-01

The area to the W-SW of the Lut Block in Iran has experienced numerous historical and recent destructive earthquakes. We examined a number of faults in this area that have high potential for generating destructive earthquakes. In this study a number of faults are introduced and named for the first time. These new faults are Takdar, Dehno, Suru, Hojat Abad, North Faryab, North Kahnoj, Heydarabad, Khatun Abad and South Faryab. For a group of previously known faults, their mechanism and geological offsets are investigated for the first time. This group of faults include East Nayband, West Nayband, Sardueiyeh, Dalfard, Khordum, South Jabal-e-Barez, and North Jabal-e-Barez. The N-S fault systems of Sabzevaran, Gowk, and Nayband induce slip on the E-W, NE-SW and NW-SE fault systems. The faulting patterns appear to preserve different stages of fault development. We investigated the distribution of active faults and the role that they play in accommodating tectonic strain in the SW-Lut. In the study area, the fault systems with en-echelon arrangement create structures such as restraining and releasing stepover, fault bend and pullapart basin. The main mechanism for fault growth in the region seems to be 'segment linkage of preexisting weaknesses' and also for a limited area through 'process zone'. Estimations are made for the likely magnitudes of separate or combined failure of the fault segments. Such magnitudes are used in hazard analysis of the region.

Response of deformation patterns to reorganizations of the southern San Andreas fault system since ca. 1.5 Ma

NASA Astrophysics Data System (ADS)

Cooke, M. L.; Fattaruso, L.; Dorsey, R. J.; Housen, B. A.

2015-12-01

Between ~1.5 and 1.1 Ma, the southern San Andreas fault system underwent a major reorganization that included initiation of the San Jacinto fault and termination of slip on the extensional West Salton detachment fault. The southern San Andreas fault itself has also evolved since this time, with several shifts in activity among fault strands within San Gorgonio Pass. We use three-dimensional mechanical Boundary Element Method models to investigate the impact of these changes to the fault network on deformation patterns. A series of snapshot models of the succession of active fault geometries explore the role of fault interaction and tectonic loading in abandonment of the West Salton detachment fault, initiation of the San Jacinto fault, and shifts in activity of the San Andreas fault. Interpreted changes to uplift patterns are well matched by model results. These results support the idea that growth of the San Jacinto fault led to increased uplift rates in the San Gabriel Mountains and decreased uplift rates in the San Bernardino Mountains. Comparison of model results for vertical axis rotation to data from paleomagnetic studies reveals a good match to local rotation patterns in the Mecca Hills and Borrego Badlands. We explore the mechanical efficiency at each step in the evolution, and find an overall trend toward increased efficiency through time. Strain energy density patterns are used to identify regions of off-fault deformation and potential incipient faulting. These patterns support the notion of north-to-south propagation of the San Jacinto fault during its initiation. The results of the present-day model are compared with microseismicity focal mechanisms to provide additional insight into the patterns of off-fault deformation within the southern San Andreas fault system.

Fault Management Techniques in Human Spaceflight Operations

NASA Technical Reports Server (NTRS)

O'Hagan, Brian; Crocker, Alan

2006-01-01

This paper discusses human spaceflight fault management operations. Fault detection and response capabilities available in current US human spaceflight programs Space Shuttle and International Space Station are described while emphasizing system design impacts on operational techniques and constraints. Preflight and inflight processes along with products used to anticipate, mitigate and respond to failures are introduced. Examples of operational products used to support failure responses are presented. Possible improvements in the state of the art, as well as prioritization and success criteria for their implementation are proposed. This paper describes how the architecture of a command and control system impacts operations in areas such as the required fault response times, automated vs. manual fault responses, use of workarounds, etc. The architecture includes the use of redundancy at the system and software function level, software capabilities, use of intelligent or autonomous systems, number and severity of software defects, etc. This in turn drives which Caution and Warning (C&W) events should be annunciated, C&W event classification, operator display designs, crew training, flight control team training, and procedure development. Other factors impacting operations are the complexity of a system, skills needed to understand and operate a system, and the use of commonality vs. optimized solutions for software and responses. Fault detection, annunciation, safing responses, and recovery capabilities are explored using real examples to uncover underlying philosophies and constraints. These factors directly impact operations in that the crew and flight control team need to understand what happened, why it happened, what the system is doing, and what, if any, corrective actions they need to perform. If a fault results in multiple C&W events, or if several faults occur simultaneously, the root cause(s) of the fault(s), as well as their vehicle-wide impacts, must be determined in order to maintain situational awareness. This allows both automated and manual recovery operations to focus on the real cause of the fault(s). An appropriate balance must be struck between correcting the root cause failure and addressing the impacts of that fault on other vehicle components. Lastly, this paper presents a strategy for using lessons learned to improve the software, displays, and procedures in addition to determining what is a candidate for automation. Enabling technologies and techniques are identified to promote system evolution from one that requires manual fault responses to one that uses automation and autonomy where they are most effective. These considerations include the value in correcting software defects in a timely manner, automation of repetitive tasks, making time critical responses autonomous, etc. The paper recommends the appropriate use of intelligent systems to determine the root causes of faults and correctly identify separate unrelated faults.

Structural setting and kinematics of Nubian fault system, SE Western Desert, Egypt: An example of multi-reactivated intraplate strike-slip faults

NASA Astrophysics Data System (ADS)

Sakran, Shawky; Said, Said Mohamed

2018-02-01

Detailed surface geological mapping and subsurface seismic interpretation have been integrated to unravel the structural style and kinematic history of the Nubian Fault System (NFS). The NFS consists of several E-W Principal Deformation Zones (PDZs) (e.g. Kalabsha fault). Each PDZ is defined by spectacular E-W, WNW and ENE dextral strike-slip faults, NNE sinistral strike-slip faults, NE to ENE folds, and NNW normal faults. Each fault zone has typical self-similar strike-slip architecture comprising multi-scale fault segments. Several multi-scale uplifts and basins were developed at the step-over zones between parallel strike-slip fault segments as a result of local extension or contraction. The NNE faults consist of right-stepping sinistral strike-slip fault segments (e.g. Sin El Kiddab fault). The NNE sinistral faults extend for long distances ranging from 30 to 100 kms and cut one or two E-W PDZs. Two nearly perpendicular strike-slip tectonic regimes are recognized in the NFS; an inactive E-W Late Cretaceous - Early Cenozoic dextral transpression and an active NNE sinistral shear.

Paleoseismology of Sinistral-Slip Fault System, Focusing on the Mae Chan Fault, on the Shan Plateau, SE Asia.

NASA Astrophysics Data System (ADS)

Curtiss, E. R.; Weldon, R. J.; Wiwegwin, W.; Weldon, E. M.

2017-12-01

The Shan Plateau, which includes portions of Myanmar, China, Thailand, Laos, and Vietnam lies between the dextral NS-trending Sagaing and SE-trending Red River faults and contains 14 active E-W sinistral-slip faults, including the Mae Chan Fault (MCF) in northern Thailand. The last ground-rupturing earthquake to occur on the broader sinistral fault system was the M6.8 Tarlay earthquake in Myanmar in March 2011 on the Nam Ma fault immediately north of the MCF the last earthquake to occur on the MCF was a M4.0 in the 5th century that destroyed the entire city of Wiang Yonok (Morley et al., 2011). We report on a trenching study of the MCF, which is part of a broader study to create a regional seismic hazard map of the entire Shan Plateau. By studying the MCF, which appears to be representative of the sinistral faults, and easy to work on, we hope to characterize both it and the other unstudied faults in the system. As part of a paleoseismology training course we dug two trenches at the Pa Tueng site on the MCF, within an offset river channel and the trenches exposed young sediment with abundant charcoal (in process of dating), cultural artifacts, and evidence for the last two (or three) ground-rupturing earthquakes on the fault. We hope to use the data from this site to narrow the recurrence interval, which is currently to be 2,000-4,000 years and the slip rate of 1-2 mm/year, being developed at other sites on the fault. By extrapolating the data of the MCF to the other faults we will have a better understanding of the whole fault system. Once we have characterized the MCF, we plan to use geomorphic offsets and strain rates from regional GPS to relatively estimate the activity of the other faults in this sinistral system.

Estimation of Faults in DC Electrical Power System

NASA Technical Reports Server (NTRS)

Gorinevsky, Dimitry; Boyd, Stephen; Poll, Scott

2009-01-01

This paper demonstrates a novel optimization-based approach to estimating fault states in a DC power system. Potential faults changing the circuit topology are included along with faulty measurements. Our approach can be considered as a relaxation of the mixed estimation problem. We develop a linear model of the circuit and pose a convex problem for estimating the faults and other hidden states. A sparse fault vector solution is computed by using 11 regularization. The solution is computed reliably and efficiently, and gives accurate diagnostics on the faults. We demonstrate a real-time implementation of the approach for an instrumented electrical power system testbed, the ADAPT testbed at NASA ARC. The estimates are computed in milliseconds on a PC. The approach performs well despite unmodeled transients and other modeling uncertainties present in the system.

Survivable algorithms and redundancy management in NASA's distributed computing systems

NASA Technical Reports Server (NTRS)

Malek, Miroslaw

1992-01-01

The design of survivable algorithms requires a solid foundation for executing them. While hardware techniques for fault-tolerant computing are relatively well understood, fault-tolerant operating systems, as well as fault-tolerant applications (survivable algorithms), are, by contrast, little understood, and much more work in this field is required. We outline some of our work that contributes to the foundation of ultrareliable operating systems and fault-tolerant algorithm design. We introduce our consensus-based framework for fault-tolerant system design. This is followed by a description of a hierarchical partitioning method for efficient consensus. A scheduler for redundancy management is introduced, and application-specific fault tolerance is described. We give an overview of our hybrid algorithm technique, which is an alternative to the formal approach given.

Effects of Strike-Slip Fault Segmentation on Earthquake Energy and Seismic Hazard

NASA Astrophysics Data System (ADS)

Madden, E. H.; Cooke, M. L.; Savage, H. M.; McBeck, J.

2014-12-01

Many major strike-slip faults are segmented along strike, including those along plate boundaries in California and Turkey. Failure of distinct fault segments at depth may be the source of multiple pulses of seismic radiation observed for single earthquakes. However, how and when segmentation affects fault behavior and energy release is the basis of many outstanding questions related to the physics of faulting and seismic hazard. These include the probability for a single earthquake to rupture multiple fault segments and the effects of segmentation on earthquake magnitude, radiated seismic energy, and ground motions. Using numerical models, we quantify components of the earthquake energy budget, including the tectonic work acting externally on the system, the energy of internal rock strain, the energy required to overcome fault strength and initiate slip, the energy required to overcome frictional resistance during slip, and the radiated seismic energy. We compare the energy budgets of systems of two en echelon fault segments with various spacing that include both releasing and restraining steps. First, we allow the fault segments to fail simultaneously and capture the effects of segmentation geometry on the earthquake energy budget and on the efficiency with which applied displacement is accommodated. Assuming that higher efficiency correlates with higher probability for a single, larger earthquake, this approach has utility for assessing the seismic hazard of segmented faults. Second, we nucleate slip along a weak portion of one fault segment and let the quasi-static rupture propagate across the system. Allowing fractures to form near faults in these models shows that damage develops within releasing steps and promotes slip along the second fault, while damage develops outside of restraining steps and can prohibit slip along the second fault. Work is consumed in both the propagation of and frictional slip along these new fractures, impacting the energy available for further slip and for subsequent earthquakes. This suite of models reveals that efficiency may be a useful tool for determining the relative seismic hazard of different segmented fault systems, while accounting for coseismic damage zone production is critical in assessing fault interactions and the associated energy budgets of specific systems.

A Unified Nonlinear Adaptive Approach for Detection and Isolation of Engine Faults

NASA Technical Reports Server (NTRS)

Tang, Liang; DeCastro, Jonathan A.; Zhang, Xiaodong; Farfan-Ramos, Luis; Simon, Donald L.

2010-01-01

A challenging problem in aircraft engine health management (EHM) system development is to detect and isolate faults in system components (i.e., compressor, turbine), actuators, and sensors. Existing nonlinear EHM methods often deal with component faults, actuator faults, and sensor faults separately, which may potentially lead to incorrect diagnostic decisions and unnecessary maintenance. Therefore, it would be ideal to address sensor faults, actuator faults, and component faults under one unified framework. This paper presents a systematic and unified nonlinear adaptive framework for detecting and isolating sensor faults, actuator faults, and component faults for aircraft engines. The fault detection and isolation (FDI) architecture consists of a parallel bank of nonlinear adaptive estimators. Adaptive thresholds are appropriately designed such that, in the presence of a particular fault, all components of the residual generated by the adaptive estimator corresponding to the actual fault type remain below their thresholds. If the faults are sufficiently different, then at least one component of the residual generated by each remaining adaptive estimator should exceed its threshold. Therefore, based on the specific response of the residuals, sensor faults, actuator faults, and component faults can be isolated. The effectiveness of the approach was evaluated using the NASA C-MAPSS turbofan engine model, and simulation results are presented.

Active tectonic deformation of the western Indian plate boundary: A case study from the Chaman Fault System

NASA Astrophysics Data System (ADS)

Crupa, Wanda E.; Khan, Shuhab D.; Huang, Jingqiu; Khan, Abdul S.; Kasi, Aimal

2017-10-01

Collision of the Eurasian and Indian plates has resulted in two spatially offset subduction zones, the Makran subduction zone to the south and the Himalayan convergent margin to the north. These zones are linked by a system of left-lateral strike-slip faults known as the Chaman Fault System, ∼1200 km, which spans along western Pakistan. Although this is one of the greatest strike-slip faults, yet temporal and spatial variation in displacement has not been adequately defined along this fault system. This study conducted geomorphic and geodetic investigations along the Chaman Fault in a search for evidence of spatial variations in motion. Four study areas were selected over the span of the Chaman Fault: (1) Tarnak-Rud area over the Tarnak-Rud valley, (2) Spinatizha area over the Spinatizha Mountain Range, (3) Nushki area over the Nushki basin, and (4) Kharan area over the northern tip of the Central Makran Mountains. Remote sensing data allowed for in depth mapping of different components and faults within the Kohjak group. Wind and water gap pairs along with offset rivers were identified using high-resolution imagery and digital-elevation models to show displacement for the four study areas. The mountain-front-sinuosity ratio, valley height-to-width-ratio, and the stream-length-gradient index were calculated and used to determine the relative tectonic activity of each area. These geomorphic indices suggest that the Kharan area is the most active and the Tarnak-Rud area is the least active. GPS data were processed into a stable Indian plate reference frame and analyzed. Fault parallel velocity versus fault normal distance yielded a ∼8-10 mm/yr displacement rate along the Chaman Fault just north of the Spinatizha area. InSAR data were also integrated to assess displacement rates along the fault system. Geodetic data support that ultra-slow earthquakes similar to those that strike along other major strike-slip faults, such as the San Andreas Fault System, are possible along the northern segments of the Chaman Fault zone. Geomorphic data suggest that the Chaman Fault along southern part is not very active now but may have gone through high tectonic activity in the past.

Audio-frequency magnetotelluric imaging of the Hijima fault, Yamasaki fault system, southwest Japan

NASA Astrophysics Data System (ADS)

Yamaguchi, S.; Ogawa, Y.; Fuji-Ta, K.; Ujihara, N.; Inokuchi, H.; Oshiman, N.

2010-04-01

An audio-frequency magnetotelluric (AMT) survey was undertaken at ten sites along a transect across the Hijima fault, a major segment of the Yamasaki fault system, Japan. The data were subjected to dimensionality analysis, following which two-dimensional inversions for the TE and TM modes were carried out. This model is characterized by (1) a clear resistivity boundary that coincides with the downward projection of the surface trace of the Hijima fault, (2) a resistive zone (>500 Ω m) that corresponds to Mesozoic sediment, and (3) shallow and deep two highly conductive zones (30-40 Ω m) along the fault. The shallow conductive zone is a common feature of the Yamasaki fault system, whereas the deep conductor is a newly discovered feature at depths of 800-1,800 m to the southwest of the fault. The conductor is truncated by the Hijima fault to the northeast, and its upper boundary is the resistive zone. Both conductors are interpreted to represent a combination of clay minerals and a fluid network within a fault-related fracture zone. In terms of the development of the fluid networks, the fault core of the Hijima fault and the highly resistive zone may play important roles as barriers to fluid flow on the northeast and upper sides of the conductive zones, respectively.

Along-strike variations of the partitioning of convergence across the Haiyuan fault system detected by InSAR

NASA Astrophysics Data System (ADS)

Daout, S.; Jolivet, R.; Lasserre, C.; Doin, M.-P.; Barbot, S.; Tapponnier, P.; Peltzer, G.; Socquet, A.; Sun, J.

2016-04-01

Oblique convergence across Tibet leads to slip partitioning with the coexistence of strike-slip, normal and thrust motion on major fault systems. A key point is to understand and model how faults interact and accumulate strain at depth. Here, we extract ground deformation across the Haiyuan Fault restraining bend, at the northeastern boundary of the Tibetan plateau, from Envisat radar data spanning the 2001-2011 period. We show that the complexity of the surface displacement field can be explained by the partitioning of a uniform deep-seated convergence. Mountains and sand dunes in the study area make the radar data processing challenging and require the latest developments in processing procedures for Synthetic Aperture Radar interferometry. The processing strategy is based on a small baseline approach. Before unwrapping, we correct for atmospheric phase delays from global atmospheric models and digital elevation model errors. A series of filtering steps is applied to improve the signal-to-noise ratio across high ranges of the Tibetan plateau and the phase unwrapping capability across the fault, required for reliable estimate of fault movement. We then jointly invert our InSAR time-series together with published GPS displacements to test a proposed long-term slip-partitioning model between the Haiyuan and Gulang left-lateral Faults and the Qilian Shan thrusts. We explore the geometry of the fault system at depth and associated slip rates using a Bayesian approach and test the consistency of present-day geodetic surface displacements with a long-term tectonic model. We determine a uniform convergence rate of 10 [8.6-11.5] mm yr-1 with an N89 [81-97]°E across the whole fault system, with a variable partitioning west and east of a major extensional fault-jog (the Tianzhu pull-apart basin). Our 2-D model of two profiles perpendicular to the fault system gives a quantitative understanding of how crustal deformation is accommodated by the various branches of this thrust/strike-slip fault system and demonstrates how the geometry of the Haiyuan fault system controls the partitioning of the deep secular motion.

Implementation of an experimental fault-tolerant memory system

NASA Technical Reports Server (NTRS)

Carter, W. C.; Mccarthy, C. E.

1976-01-01

The experimental fault-tolerant memory system described in this paper has been designed to enable the modular addition of spares, to validate the theoretical fault-secure and self-testing properties of the translator/corrector, to provide a basis for experiments using the new testing and correction processes for recovery, and to determine the practicality of such systems. The hardware design and implementation are described, together with methods of fault insertion. The hardware/software interface, including a restricted single error correction/double error detection (SEC/DED) code, is specified. Procedures are carefully described which, (1) test for specified physical faults, (2) ensure that single error corrections are not miscorrections due to triple faults, and (3) enable recovery from double errors.

Measurement and analysis of workload effects on fault latency in real-time systems

NASA Technical Reports Server (NTRS)

Woodbury, Michael H.; Shin, Kang G.

1990-01-01

The authors demonstrate the need to address fault latency in highly reliable real-time control computer systems. It is noted that the effectiveness of all known recovery mechanisms is greatly reduced in the presence of multiple latent faults. The presence of multiple latent faults increases the possibility of multiple errors, which could result in coverage failure. The authors present experimental evidence indicating that the duration of fault latency is dependent on workload. A synthetic workload generator is used to vary the workload, and a hardware fault injector is applied to inject transient faults of varying durations. This method makes it possible to derive the distribution of fault latency duration. Experimental results obtained from the fault-tolerant multiprocessor at the NASA Airlab are presented and discussed.

Structural Data for the Columbus Salt Marsh Geothermal Area - GIS Data

DOE Data Explorer

Faulds, James E.

2011-12-31

Shapefiles and spreadsheets of structural data, including attitudes of faults and strata and slip orientations of faults. - Detailed geologic mapping of ~30 km2 was completed in the vicinity of the Columbus Marsh geothermal field to obtain critical structural data that would elucidate the structural controls of this field. - Documenting E‐ to ENE‐striking left lateral faults and N‐ to NNE‐striking normal faults. - Some faults cut Quaternary basalts. - This field appears to occupy a displacement transfer zone near the eastern end of a system of left‐lateral faults. ENE‐striking sinistral faults diffuse into a system of N‐ to NNE‐striking normal faults within the displacement transfer zone. - Columbus Marsh therefore corresponds to an area of enhanced extension and contains a nexus of fault intersections, both conducive for geothermal activity.

An autonomous fault detection, isolation, and recovery system for a 20-kHz electric power distribution test bed

NASA Technical Reports Server (NTRS)

Quinn, Todd M.; Walters, Jerry L.

1991-01-01

Future space explorations will require long term human presence in space. Space environments that provide working and living quarters for manned missions are becoming increasingly larger and more sophisticated. Monitor and control of the space environment subsystems by expert system software, which emulate human reasoning processes, could maintain the health of the subsystems and help reduce the human workload. The autonomous power expert (APEX) system was developed to emulate a human expert's reasoning processes used to diagnose fault conditions in the domain of space power distribution. APEX is a fault detection, isolation, and recovery (FDIR) system, capable of autonomous monitoring and control of the power distribution system. APEX consists of a knowledge base, a data base, an inference engine, and various support and interface software. APEX provides the user with an easy-to-use interactive interface. When a fault is detected, APEX will inform the user of the detection. The user can direct APEX to isolate the probable cause of the fault. Once a fault has been isolated, the user can ask APEX to justify its fault isolation and to recommend actions to correct the fault. APEX implementation and capabilities are discussed.

Silicon oxidation in fluoride solutions

NASA Technical Reports Server (NTRS)

Sancier, K. M.; Kapur, V.

1980-01-01

Silicon is produced in a NaF, Na2SiF6, and Na matrix when SiF4 is reduced by metallic sodium. Hydrogen is evolved during acid leaching to separate the silicon from the accompanying reaction products, NaF and Na2SiF6. The hydrogen evolution reaction was studied under conditions simulating leaching conditions by making suspensions of the dry silicon powder in aqueous fluoride solutions. The mechanism for the hydrogen evolution is discussed in terms of spontaneous oxidation of silicon resulting from the cooperative effects of (1) elemental sodium in the silicon that reacts with water to remove a protective silica layer, leaving clean reactive silicon, and (2) fluoride in solution that complexes with the oxidized silicon in solution and retards formation of a protective hydrous oxide gel.

Evaluation of different fluoridated dentifrice formulations using an in situ erosion remineralization model.

PubMed

Barlow, A P; Sufi, F; Mason, S C

2009-01-01

The objective of these three clinical in situ studies was to investigate the relative performance of commercially available and experimental dentifrice formulations, having different fluoride sources and excipient ingredients, at remineralizing a bovine enamel surface previously softened by a dietary acid challenge. Each study utilized the same randomized, placebo-controlled, single-blind, crossover design. Subjects undertook single brushings of their natural teeth, with an in situ appliance in place, using different dentifrices in a randomly assigned order. Study A involved 58 subjects with the following dentifrices: Sensodyne Pronamel (1450 ppm F as NaF/5% KNO3); Blend-a-Med Classic (1450 ppm F as NaF); and a matched (Pronamel) placebo control (0 ppm F). Study B involved 56 subjects with the following dentifrices: Sensodyne Pronamel (1150 ppm F as NaF/5% KNO3); Crest Cavity Protection (1100 ppm F as NaF); Crest Pro-Health (0.454% SnF2 [1100 ppm F]/sodium hexametaphosphate); and a matched (Pronamel) placebo control (0 ppm F). Study C involved 56 subjects with the following dentifrices: Sensodyne Pronamel (1150 ppm F as NaF/5% KNO3); Sensodyne Pronamel Gentle Whitening (1150 ppm F as NaF/5% KNO3); Colgate Sensitive Multi Protection (1000 ppm F as NaMFP/5.53% potassium citrate/2% zinc citrate); and a matched (Pronamel) placebo control (0 ppm F). Subjects wore their palatal appliances holding eight bovine enamel blocks, previously exposed for 25 minutes to an in vitro erosive challenge with grapefruit juice, for the duration of the experiment. Five minutes after appliance insertion, subjects undertook a supervised, 90-second brush/rinse regimen with their assigned dentifrice. Surface microhardness (SMH) of the specimens was determined prior to the erosive challenge (baseline), after the in vitro erosive challenge, and were remeasured after four hours in situ remineralization following the tooth brushing event. Finally, SMH values were determined after a second in vitro erosive challenge at the end of the in situ remineralization period. Statistical analyses included ANOVA and pair-wise comparisons between treatments, testing at a 5% significance level. All three studies demonstrated significantly greater percent surface microhardness recovery (% SMHr) and percent relative erosion resistance (% RER) for dentifrices containing sodium fluoride compared to placebo controls. Overall, significantly greater % SMHr (p < 0.0001) was observed for Sensodyne Pronamel compared to Blend-a-Med Classic, Crest Pro-Health, and Colgate Sensitive Multi Protection dentifrices. Similarly, Sensodyne Pronamel delivered directionally better % RER vs. Blend-a-Med Classic (p = 0.0731), and significantly higher % RER vs. Crest Pro-Health (p = 0.0074) and Colgate Sensitive Multi Protection (p <0.0001). Crest Cavity Protection demonstrated significantly better % RER (p = 0.031) than Crest Pro-Health, which in turn demonstrated significantly better % RER than the placebo control (p < 0.0001). No other statistically significant between-product comparisons were observed. The results of these in situ studies support the effectiveness of dentifrices containing sodium fluoride to reharden enamel previously softened with an erosive challenge. Furthermore, these studies demonstrate the protective effects conferred to enamel, from erosion following the remineralization process in the presence of "ionic" fluoride. Under clinically relevant conditions, Sensodyne Pronamel and Sensodyne Pronamel Gentle Whitening offered superior anti-erosion performance compared to currently marketed dentifrice controls. These studies reinforce previous research indicating the importance of formulation effects on the relative remineralization performance of dentifrices under erosive conditions.

Shortening accommodated by extension-parallel folding of detachment faults during oblique rifting in the Gulf of California

NASA Astrophysics Data System (ADS)

Seiler, Christian; Fletcher, John

2013-04-01

Large-scale fault corrugations or megamullions are a common feature of detachment faults and form either as original fault grooves, displacement-gradient folds or constrictional folds parallel to the extension direction. In highly oblique extensional settings such as the Gulf of California, horizontal shortening perpendicular to the extension direction is an inherent part of the regional stress field and likely forms a key factor during the development of extension-parallel fault corrugations. However, the amount of horizontal shortening absorbed by megamullions is difficult to quantify, and constrictional folding is not normally thought to accommodate significant strike-slip deformation. The Las Cuevitas and Santa Rosa detachments are two low-angle normal fault systems exposed on the Gulf of California rifted margin in northeastern Baja California, Mexico. The two detachments accommodate between ~7-9km of SE-directed extension and represent the next significant set of faults in direction of transport from the rift breakaway fault. Fault kinematics are highly complex, but suggest integrated normal, oblique- and strike-slip faulting, with kinematics controlled by the orientation of faults with respect to the regional transtensional stress field. Both fault systems are strongly corrugated, with megamullion amplitudes of ~4-7km and half wavelenghts of between ~15 to 20km. Differential folding of the syntectonic basin-fill of the supradetachment basins strongly suggest that the observed megamullions formed largely, though not exclusively, due to constrictional folding associated with the transtensional stress regime of the plate boundary. This is consistent with basin-scale facies variations that record differential uplift and subsidence in antiformal and synformal megamullion domains, respectively. Compared to the two detachments, the San Pedro Martir fault - the master fault of the rift system at this latitude - shows more subtle fault corrugations with amplitudes of <3km. Unlike the Las Cuevitas and Santa Rosa detachments, though, there is no evidence for constrictional folding on the San Pedro Martir fault. Instead, the observed corrugations likely represent original grooves of the fault plane, formed as adjacent fault nuclei joined along-strike during fault growth. Comparison between the sinuosity of the San Pedro Martir fault (1.08), attributed entirely to original fault asperities, with the sinuosity of the two detachment systems (Las Cuevitas detachment: 1.17, Santa Rosa detachment: 1.22), suggests that about 10% of shortening occurred on each of the two detachments due to synextensional constrictional folding. This corresponds to a combined total of ~8km of N-S shortening, or ~10km of dextral shear resolved in direction of the relative plate motion, and occurs in addition to ~21km of right-lateral strain accommodated by clockwise vertical-axis block rotations. Thus, strain in this part of the rift system was partitioned between discrete extensional faulting on the two detachment systems, and significant right-lateral shear accommodated by distributed volume deformation.

3D Constraints On Fault Architecture and Strain Distribution of the Newport-Inglewood Rose Canyon and San Onofre Trend Fault Systems

NASA Astrophysics Data System (ADS)

Holmes, J. J.; Driscoll, N. W.; Kent, G. M.

2017-12-01

The Inner California Borderlands (ICB) is situated off the coast of southern California and northern Baja. The structural and geomorphic characteristics of the area record a middle Oligocene transition from subduction to microplate capture along the California coast. Marine stratigraphic evidence shows large-scale extension and rotation overprinted by modern strike-slip deformation. Geodetic and geologic observations indicate that approximately 6-8 mm/yr of Pacific-North American relative plate motion is accommodated by offshore strike-slip faulting in the ICB. The farthest inshore fault system, the Newport-Inglewood Rose Canyon (NIRC) Fault is a dextral strike-slip system that is primarily offshore for approximately 120 km from San Diego to the San Joaquin Hills near Newport Beach, California. Based on trenching and well data, the NIRC Fault Holocene slip rate is 1.5-2.0 mm/yr to the south and 0.5-1.0 mm/yr along its northern extent. An earthquake rupturing the entire length of the system could produce an Mw 7.0 earthquake or larger. West of the main segments of the NIRC Fault is the San Onofre Trend (SOT) along the continental slope. Previous work concluded that this is part of a strike-slip system that eventually merges with the NIRC Fault. Others have interpreted this system as deformation associated with the Oceanside Blind Thrust Fault purported to underlie most of the region. In late 2013, we acquired the first high-resolution 3D Parallel Cable (P-Cable) seismic surveys of the NIRC and SOT faults as part of the Southern California Regional Fault Mapping project. Analysis of stratigraphy and 3D mapping of this new data has yielded a new kinematic fault model of the area that provides new insight on deformation caused by interactions in both compressional and extensional regimes. For the first time, we can reconstruct fault interaction and investigate how strain is distributed through time along a typical strike-slip margin using 3D constraints on fault architecture.

A fault-tolerant intelligent robotic control system

NASA Technical Reports Server (NTRS)

Marzwell, Neville I.; Tso, Kam Sing

1993-01-01

This paper describes the concept, design, and features of a fault-tolerant intelligent robotic control system being developed for space and commercial applications that require high dependability. The comprehensive strategy integrates system level hardware/software fault tolerance with task level handling of uncertainties and unexpected events for robotic control. The underlying architecture for system level fault tolerance is the distributed recovery block which protects against application software, system software, hardware, and network failures. Task level fault tolerance provisions are implemented in a knowledge-based system which utilizes advanced automation techniques such as rule-based and model-based reasoning to monitor, diagnose, and recover from unexpected events. The two level design provides tolerance of two or more faults occurring serially at any level of command, control, sensing, or actuation. The potential benefits of such a fault tolerant robotic control system include: (1) a minimized potential for damage to humans, the work site, and the robot itself; (2) continuous operation with a minimum of uncommanded motion in the presence of failures; and (3) more reliable autonomous operation providing increased efficiency in the execution of robotic tasks and decreased demand on human operators for controlling and monitoring the robotic servicing routines.

Fault-tolerant Control of a Cyber-physical System

NASA Astrophysics Data System (ADS)

Roxana, Rusu-Both; Eva-Henrietta, Dulf

2017-10-01

Cyber-physical systems represent a new emerging field in automatic control. The fault system is a key component, because modern, large scale processes must meet high standards of performance, reliability and safety. Fault propagation in large scale chemical processes can lead to loss of production, energy, raw materials and even environmental hazard. The present paper develops a multi-agent fault-tolerant control architecture using robust fractional order controllers for a (13C) cryogenic separation column cascade. The JADE (Java Agent DEvelopment Framework) platform was used to implement the multi-agent fault tolerant control system while the operational model of the process was implemented in Matlab/SIMULINK environment. MACSimJX (Multiagent Control Using Simulink with Jade Extension) toolbox was used to link the control system and the process model. In order to verify the performance and to prove the feasibility of the proposed control architecture several fault simulation scenarios were performed.

Tectonic and Structural Controls of Geothermal Activity in the Great Basin Region, Western USA

NASA Astrophysics Data System (ADS)

Faulds, J. E.; Hinz, N.; Kreemer, C. W.

2012-12-01

We are conducting a thorough inventory of structural settings of geothermal systems (>400 total) in the extensional to transtensional Great Basin region of the western USA. Most of the geothermal systems in this region are not related to upper crustal magmatism and thus regional tectonic and local structural controls are the most critical factors controlling the locations of the geothermal activity. A system of NW-striking dextral faults known as the Walker Lane accommodates ~20% of the North American-Pacific plate motion in the western Great Basin and is intimately linked to N- to NNE-striking normal fault systems throughout the region. Overall, geothermal systems are concentrated in areas with the highest strain rates within or proximal to the eastern and western margins of the Great Basin, with the high temperature systems clustering in transtensional areas of highest strain rate in the northwestern Great Basin. Enhanced extension in the northwestern Great Basin probably results from the northwestward termination of the Walker Lane and the concomitant transfer of dextral shear into west-northwest directed extension, thus producing a broad transtensional region. The capacity of geothermal power plants also correlates with strain rates, with the largest (hundreds of megawatts) along the Walker Lane or San Andreas fault system, where strain rates range from 10-100 nanostrain/yr to 1,000 nanostrain/yr, respectively. Lesser systems (tens of megawatts) reside in the Basin and Range (outside the Walker Lane), where local strain rates are typically < 10 nanostrain/yr. Of the 250+ geothermal fields catalogued, step-overs or relay ramps in normal fault zones serve as the most favorable setting, hosting ~32% of the systems. Such areas have multiple, overlapping fault strands, increased fracture density, and thus enhanced permeability. Other common settings include a) intersections between normal faults and strike-slip or oblique-slip faults (27%), where multiple minor faults connect major structures and fluids can flow readily through highly fractured, dilational quadrants, and b) normal fault terminations or tip-lines (22%), where horse-tailing generates closely-spaced faults and increased permeability. Other settings include accommodation zones (i.e., belts of intermeshing, oppositely dipping normal faults; 8%), major range-front faults (5-6%), and pull-aparts in strike-slip faults (4%). In addition, Quaternary faults lie within or near most systems. The relative scarcity of geothermal systems along displacement-maxima of major normal faults may be due to reduced permeability in thick zones of clay gouge and periodic release of stress in major earthquakes. Step-overs, terminations, intersections, and accommodation zones correspond to long-term, critically stressed areas, where fluid pathways are more likely to remain open in networks of closely-spaced, breccia-dominated fractures. These findings may help guide future exploration efforts, especially for blind geothermal systems, which probably comprise the bulk of the geothermal resources in the Great Basin.

Detection of faults and software reliability analysis

NASA Technical Reports Server (NTRS)

Knight, J. C.

1986-01-01

Multiversion or N-version programming was proposed as a method of providing fault tolerance in software. The approach requires the separate, independent preparation of multiple versions of a piece of software for some application. Specific topics addressed are: failure probabilities in N-version systems, consistent comparison in N-version systems, descriptions of the faults found in the Knight and Leveson experiment, analytic models of comparison testing, characteristics of the input regions that trigger faults, fault tolerance through data diversity, and the relationship between failures caused by automatically seeded faults.

Publications - PIR 2014-5 | Alaska Division of Geological & Geophysical

Science.gov Websites

the Iniskin Peninsula: Implications for the kinematic history of the Bruin Bay fault system, lower Iniskin Peninsula: Implications for the kinematic history of the Bruin Bay fault system, lower Cook Inlet (3.0 M) Keywords Bruin Bay Fault; Chinitna Bay; Faults; Folds; Forearc Basin; Geologic Map; Iniskin Bay

Software For Fault-Tree Diagnosis Of A System

NASA Technical Reports Server (NTRS)

Iverson, Dave; Patterson-Hine, Ann; Liao, Jack

1993-01-01

Fault Tree Diagnosis System (FTDS) computer program is automated-diagnostic-system program identifying likely causes of specified failure on basis of information represented in system-reliability mathematical models known as fault trees. Is modified implementation of failure-cause-identification phase of Narayanan's and Viswanadham's methodology for acquisition of knowledge and reasoning in analyzing failures of systems. Knowledge base of if/then rules replaced with object-oriented fault-tree representation. Enhancement yields more-efficient identification of causes of failures and enables dynamic updating of knowledge base. Written in C language, C++, and Common LISP.

Fault Management Metrics

NASA Technical Reports Server (NTRS)

Johnson, Stephen B.; Ghoshal, Sudipto; Haste, Deepak; Moore, Craig

2017-01-01

This paper describes the theory and considerations in the application of metrics to measure the effectiveness of fault management. Fault management refers here to the operational aspect of system health management, and as such is considered as a meta-control loop that operates to preserve or maximize the system's ability to achieve its goals in the face of current or prospective failure. As a suite of control loops, the metrics to estimate and measure the effectiveness of fault management are similar to those of classical control loops in being divided into two major classes: state estimation, and state control. State estimation metrics can be classified into lower-level subdivisions for detection coverage, detection effectiveness, fault isolation and fault identification (diagnostics), and failure prognosis. State control metrics can be classified into response determination effectiveness and response effectiveness. These metrics are applied to each and every fault management control loop in the system, for each failure to which they apply, and probabilistically summed to determine the effectiveness of these fault management control loops to preserve the relevant system goals that they are intended to protect.

A Novel Online Data-Driven Algorithm for Detecting UAV Navigation Sensor Faults.

PubMed

Sun, Rui; Cheng, Qi; Wang, Guanyu; Ochieng, Washington Yotto

2017-09-29

The use of Unmanned Aerial Vehicles (UAVs) has increased significantly in recent years. On-board integrated navigation sensors are a key component of UAVs' flight control systems and are essential for flight safety. In order to ensure flight safety, timely and effective navigation sensor fault detection capability is required. In this paper, a novel data-driven Adaptive Neuron Fuzzy Inference System (ANFIS)-based approach is presented for the detection of on-board navigation sensor faults in UAVs. Contrary to the classic UAV sensor fault detection algorithms, based on predefined or modelled faults, the proposed algorithm combines an online data training mechanism with the ANFIS-based decision system. The main advantages of this algorithm are that it allows real-time model-free residual analysis from Kalman Filter (KF) estimates and the ANFIS to build a reliable fault detection system. In addition, it allows fast and accurate detection of faults, which makes it suitable for real-time applications. Experimental results have demonstrated the effectiveness of the proposed fault detection method in terms of accuracy and misdetection rate.

3D Model of the Neal Hot Springs Geothermal Area

DOE Data Explorer

Faulds, James E.

2013-12-31

The Neal Hot Springs geothermal system lies in a left-step in a north-striking, west-dipping normal fault system, consisting of the Neal Fault to the south and the Sugarloaf Butte Fault to the north (Edwards, 2013). The Neal Hot Springs 3D geologic model consists of 104 faults and 13 stratigraphic units. The stratigraphy is sub-horizontal to dipping <10 degrees and there is no predominant dip-direction. Geothermal production is exclusively from the Neal Fault south of, and within the step-over, while geothermal injection is into both the Neal Fault to the south of the step-over and faults within the step-over.

Association of the 1886 Charleston, South Carolina, earthquake and seismicity near Summervile with a 12º bend in the East Coast fault system and triple-fault junctions

USGS Publications Warehouse

Marple, R.; Miller, R.

2006-01-01

Seismic-reflection data were integrated with other geophysical, geologic, and seismicity data to better determine the location and nature of buried faults in the Charleston, South Carolina, region. Our results indicate that the 1886 Charleston, South Carolina, earthquake and seismicity near Summerville are related to local stresses caused by a 12?? bend in the East Coast fault system (ECFS) and two triple-fault junctions. One triple junction is formed by the intersection of the northwest-trending Ashley River fault with the two segments of the ECFS north and south of the bend. The other triple junction is formed by the intersection of the northeast-trending Summerville fault and a newly discovered northwest-trending Berkeley fault with the ECFS about 10 km north of the bend. The Summerville fault is a northwest-dipping border fault of the Triassic-age Jedburg basin that is undergoing reverse-style reactivation. This reverse-style reactivation is unusual because the Summerville fault parallels the regional stress field axis, suggesting that the reactivation is from stresses applied by dextral motion on the ECFS. The southwest-dip and reverse-type motion of the Berkeley fault are interpreted from seismicity data and a seismic-reflection profile in the western part of the study area. Our results also indicate that the East Coast fault system is a Paleozoic basement fault and that its reactivation since early Mesozoic time has fractured through the overlying allochthonous terranes.

Structural Inventory of Great Basin Geothermal Systems and Definition of Favorable Structural Settings

DOE Data Explorer

Faulds, James E.

2013-12-31

Over the course of the entire project, field visits were made to 117 geothermal systems in the Great Basin region. Major field excursions, incorporating visits to large groups of systems, were conducted in western Nevada, central Nevada, northwestern Nevada, northeastern Nevada, east‐central Nevada, eastern California, southern Oregon, and western Utah. For example, field excursions to the following areas included visits of multiple geothermal systems: - Northwestern Nevada: Baltazor Hot Spring, Blue Mountain, Bog Hot Spring, Dyke Hot Springs, Howard Hot Spring, MacFarlane Hot Spring, McGee Mountain, and Pinto Hot Springs in northwest Nevada. - North‐central to northeastern Nevada: Beowawe, Crescent Valley (Hot Springs Point), Dann Ranch (Hand‐me‐Down Hot Springs), Golconda, and Pumpernickel Valley (Tipton Hot Springs) in north‐central to northeast Nevada. - Eastern Nevada: Ash Springs, Chimney Hot Spring, Duckwater, Hiko Hot Spring, Hot Creek Butte, Iverson Spring, Moon River Hot Spring, Moorman Spring, Railroad Valley, and Williams Hot Spring in eastern Nevada. - Southwestern Nevada‐eastern California: Walley’s Hot Spring, Antelope Valley, Fales Hot Springs, Buckeye Hot Springs, Travertine Hot Springs, Teels Marsh, Rhodes Marsh, Columbus Marsh, Alum‐Silver Peak, Fish Lake Valley, Gabbs Valley, Wild Rose, Rawhide‐ Wedell Hot Springs, Alkali Hot Springs, and Baileys/Hicks/Burrell Hot Springs. - Southern Oregon: Alvord Hot Spring, Antelope Hot Spring‐Hart Mountain, Borax Lake, Crump Geyser, and Mickey Hot Spring in southern Oregon. - Western Utah: Newcastle, Veyo Hot Spring, Dixie Hot Spring, Thermo, Roosevelt, Cove Fort, Red Hill Hot Spring, Joseph Hot Spring, Hatton Hot Spring, and Abraham‐Baker Hot Springs. Structural controls of 426 geothermal systems were analyzed with literature research, air photos, google‐Earth imagery, and/or field reviews (Figures 1 and 2). Of the systems analyzed, we were able to determine the structural settings of more than 240 sites. However, we found that many “systems” consisted of little more than a warm or hot well in the central part of a basin. Such “systems” were difficult to evaluate in terms of structural setting in areas lacking in geophysical data. Developed database for structural catalogue in a master spreadsheet. Data components include structural setting, primary fault orientation, presence or absence of Quaternary faulting, reservoir lithology, geothermometry, presence or absence of recent magmatism, and distinguishing blind systems from those that have surface expressions. Reviewed site locations for all 426 geothermal systems– Confirmed and/or relocated spring and geothermal sites based on imagery, maps, and other information for master database. Many systems were mislocated in the original database. In addition, some systems that included several separate springs spread over large areas were divided into two or more distinct systems. Further, all hot wells were assigned names based on their location to facilitate subsequent analyses. We catalogued systems into the following eight major groups, based on the dominant pattern of faulting (Figure 1): - Major normal fault segments (i.e., near displacement maxima). - Fault bends. - Fault terminations or tips. - Step‐overs or relay ramps in normal faults. - Fault intersections. - Accommodation zones (i.e., belts of intermeshing oppositely dipping normal faults), - Displacement transfer zones whereby strike‐slip faults terminate in arrays of normal faults. - Transtensional pull‐aparts. These settings form a hierarchal pattern with respect to fault complexity. - Major normal faults and fault bends are the simplest. - Fault terminations are typically more complex than mid‐segments, as faults commonly break up into multiple strands or horsetail near their ends. - A fault intersection is generally more complex, as it generally contains both multiple fault strands and can include discrete di...