Histamine-dependent behavioral response to methamphetamine in 12-month-old male mice

PubMed Central

Acevedo, Summer F.; Raber, Jacob

2011-01-01

Methamphetamine (MA) use is a growing problem across the United States. Effects of MA include hyperactivity and increased anxiety. Using a mouse model system, we examined behavioral performance in the open field and elevated zero maze and shock-startle response of 12-month-old wild-type mice injected with MA once (1mg/kg) 30 min prior to behavioral testing. MA treatment resulted in behavioral sensitization in the open field, consistent with studies in younger mice. There was an increased activity in the elevated zero maze and an increased shock-startle response 30 and 60 min post-injection. Since histamine mediates some effects of MA in the brain, we assessed whether 12-month-old mice lacking histidine decarboxylase (Hdc−/−), the enzyme required to synthesize histamine, respond differently to MA than wild-type (Hdc+/+) mice. Compared to saline treatment, acute and repeated MA administration increased activity in the open field and measures of anxiety, though more so in Hdc−/− than Hdc+/+ mice. In the elevated zero maze, opposite effects of MA on activity and measures of anxiety were seen in Hdc+/+ mice. In contrast, MA similarly increased the shock-startle response in Hdc−/− and Hdc+/+ mice, compared to saline-treated genotype-matched mice. These results are similar to those in younger mice suggesting that the effects are not age-dependent. Overall, single or repeated MA treatment causes histamine-dependent changes in 12-month-old mice in the open field and elevated zero-maze, but not in the shock-startle response. PMID:21466792

Velocity profiles of interplanetary shocks

NASA Technical Reports Server (NTRS)

Cane, H. V.

1983-01-01

The type 2 radio burst was identified as a shock propagating through solar corona. Radio emission from shocks travelling through the interplanetary (IP) medium was observed. Using the drift rates of IP type II bursts the velocity characteristics of eleven shocks were investigated. It is indicated that shocks in the IP medium undergo acceleration before decelerating and that the slower shocks take longer to attain their maximum velocity.

Existence Regions of Shock Wave Triple Configurations

ERIC Educational Resources Information Center

Bulat, Pavel V.; Chernyshev, Mikhail V.

2016-01-01

The aim of the research is to create the classification for shock wave triple configurations and their existence regions of various types: type 1, type 2, type 3. Analytical solutions for limit Mach numbers and passing shock intensity that define existence region of every type of triple configuration have been acquired. The ratios that conjugate…

Chaperones and protein folding in the archaea.

PubMed

Large, Andrew T; Goldberg, Martin D; Lund, Peter A

2009-02-01

A survey of archaeal genomes for the presence of homologues of bacterial and eukaryotic chaperones reveals several interesting features. All archaea contain chaperonins, also known as Hsp60s (where Hsp is heat-shock protein). These are more similar to the type II chaperonins found in the eukaryotic cytosol than to the type I chaperonins found in bacteria, mitochondria and chloroplasts, although some archaea also contain type I chaperonin homologues, presumably acquired by horizontal gene transfer. Most archaea contain several genes for these proteins. Our studies on the type II chaperonins of the genetically tractable archaeon Haloferax volcanii have shown that only one of the three genes has to be present for the organisms to grow, but that there is some evidence for functional specialization between the different chaperonin proteins. All archaea also possess genes for prefoldin proteins and for small heat-shock proteins, but they generally lack genes for Hsp90 and Hsp100 homologues. Genes for Hsp70 (DnaK) and Hsp40 (DnaJ) homologues are only found in a subset of archaea. Thus chaperone-assisted protein folding in archaea is likely to display some unique features when compared with that in eukaryotes and bacteria, and there may be important differences in the process between euryarchaea and crenarchaea.

Effects of various types of stress on the metabolism of reserve carbohydrates in Saccharomyces cerevisiae: genetic evidence for a stress-induced recycling of glycogen and trehalose.

PubMed

Parrou, J L; Teste, M A; François, J

1997-06-01

It is well known that glycogen and trehalose accumulate in yeast under nutrient starvation or entering into the stationary phase of growth, and that high levels of trehalose are found in heat-shocked cells. However, effects of various types of stress on trehalose, and especially on glycogen, are poorly documented. Taking into account that almost all genes encoding the enzymes involved in the metabolism of these two reserve carbohydrates contain between one and several copies of the stress-responsive element (STRE), an investigation was made of the possibility of a link between the potential transcriptional induction of these genes and the accumulation of glycogen and trehalose under different stress conditions. Using transcriptional fusions, it was found that all these genes were induced in a similar fashion, although to various extents, by temperature, osmotic and oxidative stresses. Experiments performed with an msn2/msn4 double mutant proved that the transcriptional induction of the genes encoding glycogen synthase (GSY2) and trehalose-6-phosphate synthase (TPS1) was needed for the small increase in glycogen and trehalose upon exposure to a mild heat stress and salt shock. However, the extent of transcriptional activation of these genes upon stresses in wild-type strains was not correlated with a proportional rise in either glycogen or trehalose. The major explanation for this lack of correlation comes from the fact that genes encoding the enzymes of the biosynthetic and of the biodegradative pathways were almost equally induced. Hence, trehalose and glycogen accumulated to much higher levels in cells lacking neutral trehalose or glycogen phosphorylase exposed to stress conditions, which suggested that one of the major effects of stress in yeast is to induce a wasteful expenditure of energy by increasing the recycling of these molecules. We also found that transcriptional induction of STRE-controlled genes was abolished at temperatures above 40 degree C, while induction was still observed for a heat-shock-element regulated gene. Remarkably, trehalose accumulated to very high levels under this condition. This can be explained by a stimulation of trehalose synthase and inhibition of trehalose by high temperature.

Solar radio bursts of spectral type II, coronal shocks, and optical coronal transients

NASA Technical Reports Server (NTRS)

Maxwell, A.; Dryer, M.

1981-01-01

An examination is presented of the association of solar radio bursts of spectral type II and coronal shocks with solar flare ejecta observed in H-alpha, the green coronal line, and white-light coronagraphs. It is suggested that fast-moving optical coronal transients should for the most part be identified with piston-type phenomena well behind the outward-traveling shock waves that generate type II radio bursts. A general model is presented which relates type II radio bursts and coronal shocks to optically observed ejecta and consists of three main velocity regimes: (1) a quasi-hemispherical shock wave moving outward from the flare at speeds of 1000-2000 km/sec and Alfven Mach number of about 1.5; (2) the velocity of the piston driving the shock, on the order of 0.8 that of the shock; and (3) the regime of the slower-moving H-alpha ejecta, with velocities of 300-500 km/sec.

The Progenitor of Tycho’s Supernova was Not Hot and Luminous

NASA Astrophysics Data System (ADS)

Ghavamian, Parviz; Woods, T. E.; Gilfanov, M.; Badenes, C.; T. E. Woods, C. Badenes, M. Gilfanov

2018-01-01

Canonical accretion models of Type Ia supernovae predict that a hot and luminous progenitor will ionize the surrounding gas out to a radius of ∼10–100 pc for ∼100,000 years after the explosion. Tycho’s supernova of 1572 was a Type Ia explosion which produced a remnant that is currently interacting with neutral gas in the form of Balmer-dominated shocks. From analysis of these shocks and photoionization calculations, we have placed stringent upper limits on the temperature and luminosity of the progenitor of Tycho’s supernova. Hot, luminous progenitors that would have produced a greater hydrogen ionization fraction than that measured at the current SNR radius (∼3 parsecs) can thus be excluded. This rules out steadily nuclear-burning white dwarfs (i..e, supersoft X-ray sources), as well as disk emission from a Chandrasekhar-mass white dwarf accreting 1E-8 solar masses per year (recurrent novae). The lack of a Stromgren sphere around Tycho’s SNR is consistent with a double degenerate explosion, although other more exotic scenarios may be possible.

Metallographic cooling rates of L-group ordinary chondrites

NASA Technical Reports Server (NTRS)

Bennett, Marvin E.; Mcsween, Harry Y., Jr.

1993-01-01

Shock metamorphism appears to be a ubiquitous feature in L-group ordinary chondrites. Brecciation and heterogeneous melting obscure much of the early history of this meteorite group and have caused confusion as to whether L chondrites have undergone thermal metamorphism within onion-shell or rubble-pile parent bodies. Employing the most recent shock criteria, we have examined 55 Antarctic and 24 non-Antarctic L chondrites in order to identify those which have been least affected by post-accretional shock. Six low-shock samples (those with shock grade less than S4) of petrographic types L3-L5 were selected from both populations and metallographic cooling rates were obtained following the technique of Willis and Goldstein. All non-Antarctic L6 chondrites inspected were too heavily shocked to be included in this group. However, 4 shocked L6 chondrites were analyzed in order to determine what effects shock may impose on metallographic cooling rates. Metallographic cooling rates were derived by analyzing the cores of taenite grains and then measuring the distance to the nearest grain edge. Taenites were identified using backscatter imaging on a Cameca SX-50 electron microprobe. Using backscatter we were able to locate homogeneous, rust-free, nearly spherical grains. M-shaped profiles taken from grain traverses were also used to help locate the central portions of selected grains. All points which contained phosphorus above detection limits were discarded. Plots of cooling-rate data are summarized and data from the high-shock samples are presented. The lack of coherency of cooling rates for individual samples is indicative of heterogeneous cooling following shock. The data confirms the statement expressed by numerous workers that extreme care must be taken when selecting samples of L chondrites for cooling-rate studies. Data for the 6 non-Antarctic low-shock samples are also presented. The samples display a general trend in cooling rates. The lowest metamorphic grade yielded the slowest cooling rates and an increase in grade follows an increase in cooling rate. This is the opposite relationship to that predicted by the onion-shell model.

Canine gastric carcinoma: immunohistochemical expression of cell cycle proteins (p53, p21, and p16) and heat shock proteins (Hsp27 and Hsp70).

PubMed

Carrasco, V; Canfrán, S; Rodríguez-Franco, F; Benito, A; Sáinz, A; Rodríguez-Bertos, A

2011-01-01

Immunohistochemical staining for cell cycle proteins and heat shock proteins was performed on 17 canine gastric carcinomas. The immunoexpression of p53, p21, p16, Hsp27, and Hsp70 was investigated. A study was conducted to determine the histological type and parameters related to tumor malignancy. Possible associations and trends were assessed between the immunoexpression of each protein and tumor type as well as specific parameters of malignancy. High intratumor frequency of cellular p53 immunostaining was observed (61.96% average), but lower frequencies of p21 and p16 expression were present (34.65% and 10.41%, respectively). The p53 overexpression was associated with tumor infiltration (P = .0258). Expression of p21 was lower in undifferentiated carcinomas, and the loss of expression was associated with histopathological parameters characteristic of a poor prognosis such as lymphatic vessel invasion (P = .0258). The lack of p16 immunoreactivity was related to histopathological characteristics of malignancy such as the presence of evident and multiple nucleoli (P = .0475). In contrast, deep tumor infiltration was observed in those carcinomas with a high p16 index (P = .0475). Hsp70 appeared to be overexpressed in all gastric neoplasms included in this study. This is in contrast to Hsp27, because a group of tumors showed complete lack of Hsp27 immunoexpression, whereas the others displayed extensive Hsp27 immunostaining. The differences in Hsp27 did not correlate with any of the histopathological parameters, but Hsp27 immunoexpression was higher in the undifferentiated carcinoma. No significant differences in the expression of the proteins were found in canine gastric carcinomas according to their histological type. These findings may be useful for establishing a prognosis for canine gastric carcinoma.

Characteristics of coronal shock waves and solar type 2 radio bursts

NASA Technical Reports Server (NTRS)

Mann, G.; Classen, H.-T.

1995-01-01

In the solar corona shock waves generated by flares and/or coronal mass ejections can be observed by radio astronomical methods in terms of solar type 2 radio bursts. In dynamic radio spectra they appear as emission stripes slowly drifting from high to low frequencies. A sample of 25 solar type 2 radio bursts observed in the range of 40 - 170 MHz with a time resolution of 0.1 s by the new radiospectrograph of the Astrophvsikalisches Institut Potsdam in Tremsdorf is statistically investigated concerning their spectral features, i.e, drift rate, instantaneous bandwidth, and fundamental harmonic ratio. In-situ plasma wave measurements at interplanetary shocks provide the assumption that type 2 radio radiation is emitted in the vicinity of the transition region of shock waves. Thus, the instantaneous bandwidth of a solar type 2 radio burst would reflect the density jump across the associated shock wave. Comparing the inspection of the Rankine-Hugoniot relations of shock waves under coronal circumstances with those obtained from the observational study, solar type 2 radio bursts should be regarded to be generated by weak supercritical, quasi-parallel, fast magnetosonic shock waves in the corona.

Toxic shock syndrome

MedlinePlus

Staphylococcal toxic shock syndrome; Toxic shock-like syndrome; TSLS ... Toxic shock syndrome is caused by a toxin produced by some types of staphylococcus bacteria. A similar problem, called toxic shock- ...

Assessing the Role of Anhydrite in the KT Mass Extinction: Hints from Shock-loading Experiments

NASA Technical Reports Server (NTRS)

Skala, R.; Lnagenhorst, F.; Hoerz, F.

2004-01-01

Various killing mechanisms have been suggested to contribute to the mass extinctions at the KT boundary, including severe, global deterioration of the atmosphere and hydrosphere due to SO(x) released from heavily shocked, sulfate-bearing target rocks. The devolatilization of anhydrite is predominantly inferred from thermodynamic considerations and lacks experimental confirmation. To date, the experimentally determined shock behavior of anhydrite is limited to solid-state effects employing X-ray diffraction methods. The present report employs additional methods to characterize experimentally shocked anhydrite.

Evidence of staphylococcal toxic shock syndrome caused by MRSA in a mother-newborn pair.

PubMed

Rostad, Christina A; Philipsborn, Rebecca Pass; Berkowitz, Frank E

2015-04-01

A neonate and his mother presented with fever and erythroderma. The mother met full diagnostic criteria for staphylococcal toxic shock syndrome, whereas the neonate lacked hypotension and multiorgan dysfunction. A wound culture from the neonate's circumcision site grew methicillin-resistant Staphylococcus aureus containing the tst gene. This provides evidence of the first reported case of toxic shock syndrome caused by methicillin-resistant Staphylococcus aureus in a mother-newborn pair.

Why is solar cycle 24 an inefficient producer of high-energy particle events?

NASA Astrophysics Data System (ADS)

Vainio, Rami; Raukunen, Osku; Tylka, Allan J.; Dietrich, William F.; Afanasiev, Alexandr

2017-08-01

Aims: The aim of the study is to investigate the reason for the low productivity of high-energy SEPs in the present solar cycle. Methods: We employ scaling laws derived from diffusive shock acceleration theory and simulation studies including proton-generated upstream Alfvén waves to find out how the changes observed in the long-term average properties of the erupting and ambient coronal and/or solar wind plasma would affect the ability of shocks to accelerate particles to the highest energies. Results: Provided that self-generated turbulence dominates particle transport around coronal shocks, it is found that the most crucial factors controlling the diffusive shock acceleration process are the number density of seed particles and the plasma density of the ambient medium. Assuming that suprathermal populations provide a fraction of the particles injected to shock acceleration in the corona, we show that the lack of most energetic particle events as well as the lack of low charge-to-mass ratio ion species in the present cycle can be understood as a result of the reduction of average coronal plasma and suprathermal densities in the present cycle over the previous one.

Geomorphology: the Shock of the Familiar

NASA Astrophysics Data System (ADS)

Dietrich, W. E.

2008-12-01

Everyone experiences landscapes and has a sense about how they work: water runs down hill, it erodes and carries sediments, and that's about it, right? Introductory earth science text books are uniformly qualitative about the field, and leave one with little sense of wonder, and certainly not "shock". But four shocks occur if one peels away the first impressions. First, landscapes are surprisingly similar: the same forms are repeated in virtually all environments, including under the ocean and on other planets. Second, we lack theory and mechanistic observations to answer many simple first-order questions, e.g. what controls the width of a river, how does rock type control hillslope form and erosion rate, or, is there a topographic signature of life. Third, there are unexpected connections between surface erosion, deep earth processes, and climate. And fourth, the field itself, despite having been a subject of study for well over 100 years, is currently experiencing a revolution of ideas and discoveries through new tools, observatories, centers, journals, books, contributions of researchers from other disciplines, and from a significant hiring of young researchers in geomorphology. Deep messages await discovery in the simple landforms surrounding us.

Influences of the Driver and Ambient Medium Characteristics on the Formation of Shocks in the Solar Atmosphere

NASA Technical Reports Server (NTRS)

Nat, Gopalswamy; Hong, Xie; Seiji, Yashiro; Pertti, Makela; Sachiko, Akiyama

2010-01-01

Traveling interplanetary (IP) shocks were discovered in the early 1960s, but their solar origin has been controversial. Early research focused on solar flares as the source of the shocks, but when coronal mass ejections (CMEs) were discovered, it became clear that fast CMEs clearly can drive the shocks. Type II radio bursts are excellent signatures of shocks near the Sun. The close correspondence between type II radio bursts and solar energetic particles (SEPs) makes it clear that the same shock accelerates ions and electrons. A recent investigation involving a large number of IP shocks revealed that about 35% of IP shocks do not produce type II bursts or SEPs. Comparing these radio quiet (RQ) shocks with the radio loud (RL) ones revealed some interesting results: (1) there is no evidence for blast waves, in that all IP shocks can be attributed to CMEs, (2) a small fraction (20%) of RQ shocks is associated with ion enhancements at the shocks when they move past the observing spacecraft, (3) the primary difference between the RQ and RL shocks can be traced to the different kinematic properties of the associated CMEs and the variation of the characteristic speeds of the ambient medium, and (4) the shock properties measured at 1 AU are not too different for the RQ and RL cases due to the interaction of the shock driver with the IP medium that seems to erase the difference.

The Role of Inducible Hsp70, and Other Heat Shock Proteins, in Adaptive Complex of Cold Tolerance of the Fruit Fly (Drosophila melanogaster)

PubMed Central

Štětina, Tomáš; Koštál, Vladimír; Korbelová, Jaroslava

2015-01-01

Background The ubiquitous occurrence of inducible Heat Shock Proteins (Hsps) up-regulation in response to cold-acclimation and/or to cold shock, including massive increase of Hsp70 mRNA levels, often led to hasty interpretations of its role in the repair of cold injury expressed as protein denaturation or misfolding. So far, direct functional analyses in Drosophila melanogaster and other insects brought either limited or no support for such interpretations. In this paper, we analyze the cold tolerance and the expression levels of 24 different mRNA transcripts of the Hsps complex and related genes in response to cold in two strains of D. melanogaster: the wild-type and the Hsp70- null mutant lacking all six copies of Hsp70 gene. Principal Findings We found that larvae of both strains show similar patterns of Hsps complex gene expression in response to long-term cold-acclimation and during recovery from chronic cold exposures or acute cold shocks. No transcriptional compensation for missing Hsp70 gene was seen in Hsp70- strain. The cold-induced Hsps gene expression is most probably regulated by alternative splice variants C and D of the Heat Shock Factor. The cold tolerance in Hsp70- null mutants was clearly impaired only when the larvae were exposed to severe acute cold shock. No differences in mortality were found between two strains when the larvae were exposed to relatively mild doses of cold, either chronic exposures to 0°C or acute cold shocks at temperatures down to -4°C. Conclusions The up-regulated expression of a complex of inducible Hsps genes, and Hsp70 mRNA in particular, is tightly associated with cold-acclimation and cold exposure in D. melanogaster. Genetic elimination of Hsp70 up-regulation response has no effect on survival of chronic exposures to 0°C or mild acute cold shocks, while it negatively affects survival after severe acute cold shocks at temperaures below -8°C. PMID:26034990

The Role of Inducible Hsp70, and Other Heat Shock Proteins, in Adaptive Complex of Cold Tolerance of the Fruit Fly (Drosophila melanogaster).

PubMed

Štětina, Tomáš; Koštál, Vladimír; Korbelová, Jaroslava

2015-01-01

The ubiquitous occurrence of inducible Heat Shock Proteins (Hsps) up-regulation in response to cold-acclimation and/or to cold shock, including massive increase of Hsp70 mRNA levels, often led to hasty interpretations of its role in the repair of cold injury expressed as protein denaturation or misfolding. So far, direct functional analyses in Drosophila melanogaster and other insects brought either limited or no support for such interpretations. In this paper, we analyze the cold tolerance and the expression levels of 24 different mRNA transcripts of the Hsps complex and related genes in response to cold in two strains of D. melanogaster: the wild-type and the Hsp70- null mutant lacking all six copies of Hsp70 gene. We found that larvae of both strains show similar patterns of Hsps complex gene expression in response to long-term cold-acclimation and during recovery from chronic cold exposures or acute cold shocks. No transcriptional compensation for missing Hsp70 gene was seen in Hsp70- strain. The cold-induced Hsps gene expression is most probably regulated by alternative splice variants C and D of the Heat Shock Factor. The cold tolerance in Hsp70- null mutants was clearly impaired only when the larvae were exposed to severe acute cold shock. No differences in mortality were found between two strains when the larvae were exposed to relatively mild doses of cold, either chronic exposures to 0°C or acute cold shocks at temperatures down to -4°C. The up-regulated expression of a complex of inducible Hsps genes, and Hsp70 mRNA in particular, is tightly associated with cold-acclimation and cold exposure in D. melanogaster. Genetic elimination of Hsp70 up-regulation response has no effect on survival of chronic exposures to 0°C or mild acute cold shocks, while it negatively affects survival after severe acute cold shocks at temperatures below -8°C.

Analysis of transactivation potential of rice (Oryza sativa L.) heat shock factors.

PubMed

Lavania, Dhruv; Dhingra, Anuradha; Grover, Anil

2018-06-01

Based on yeast one-hybrid assays, we show that the presence of C-terminal AHA motifs is not a prerequisite for transactivation potential in rice heat shock factors. Transcriptional activation or transactivation (TA) of heat stress responsive genes takes place by binding of heat shock factors (Hsfs) to heat shock elements. Analysis of TA potential of thirteen rice (Oryza sativa L.) Hsfs (OsHsfs) carried out in this study by yeast one-hybrid assay showed that OsHsfsA3 possesses strong TA potential while OsHsfs A1a, A2a, A2b, A4a, A4d, A5, A7b, B1, B2a, B2b, B2c and B4d lack TA potential. From a near complete picture of TA potential of the OsHsf family (comprising of 25 members) emerging from this study and an earlier report from our group (Mittal et al. in FEBS J 278(17):3076-3085, 2011), it is concluded that (1) overall, six OsHsfs, namely A3, A6a, A6b, A8, C1a and C1b possess TA potential; (2) four class A OsHsfs, namely A3, A6a, A6b and A8 have TA potential out of which A6a and A6b contain AHA motifs while A3 and A8 lack AHA motifs; (3) nine class A OsHsfs, namely A1a, A2a, A2b, A2e, A4a, A4d, A5, A7a and A7b containing AHA motif(s) lack TA function in the yeast assay system; (4) all class B OsHsfs lack AHA motifs and TA potential (B4a not analyzed) and (5) though all class C OsHsf members lack AHA motifs, two members C1a and C1b possess TA function, while one member C2a lacks TA potential (C2b not analyzed). Thus, the presence or absence of AHA motif is possibly not the only factor determining TA potential of OsHsfs. Our findings will help to identify the transcriptional activators of rice heat shock response.

Does Explosive Nuclear Burning Occur in Tidal Disruption Events of White Dwarfs by Intermediate-mass Black Holes?

NASA Astrophysics Data System (ADS)

Tanikawa, Ataru; Sato, Yushi; Nomoto, Ken'ichi; Maeda, Keiichi; Nakasato, Naohito; Hachisu, Izumi

2017-04-01

We investigate nucleosynthesis in tidal disruption events (TDEs) of white dwarfs (WDs) by intermediate-mass black holes. We consider various types of WDs with different masses and compositions by means of three-dimensional (3D) smoothed particle hydrodynamics (SPH) simulations. We model these WDs with different numbers of SPH particles, N, from a few 104 to a few 107 in order to check mass resolution convergence, where SPH simulations with N > 107 (or a space resolution of several 106 cm) have unprecedentedly high resolution in this kind of simulation. We find that nuclear reactions become less active with increasing N and that these nuclear reactions are excited by spurious heating due to low resolution. Moreover, we find no shock wave generation. In order to investigate the reason for the absence of a shock wave, we additionally perform one-dimensional (1D) SPH and mesh-based simulations with a space resolution ranging from 104 to 107 cm, using a characteristic flow structure extracted from the 3D SPH simulations. We find shock waves in these 1D high-resolution simulations, one of which triggers a detonation wave. However, we must be careful of the fact that, if the shock wave emerged in an outer region, it could not trigger the detonation wave due to low density. Note that the 1D initial conditions lack accuracy to precisely determine where a shock wave emerges. We need to perform 3D simulations with ≲106 cm space resolution in order to conclude that WD TDEs become optical transients powered by radioactive nuclei.

Shock Formation Height in the Solar Corona Estimated from SDO and Radio Observations

NASA Technical Reports Server (NTRS)

Gopalswamy, N.; Nitta, N.

2011-01-01

Wave transients at EUV wavelengths and type II radio bursts are good indicators of shock formation in the solar corona. We use recent EUV wave observations from SDO and combine them with metric type II radio data to estimate the height in the corona where the shocks form. We compare the results with those obtained from other methods. We also estimate the shock formation heights independently using white-light observations of coronal mass ejections that ultimately drive the shocks.

A Morphological Analysis of Gamma-Ray Burst Early-optical Afterglows

NASA Astrophysics Data System (ADS)

Gao, He; Wang, Xiang-Gao; Mészáros, Peter; Zhang, Bing

2015-09-01

Within the framework of the external shock model of gamma-ray burst (GRB) afterglows, we perform a morphological analysis of the early-optical light curves to directly constrain model parameters. We define four morphological types, i.e., the reverse shock-dominated cases with/without the emergence of the forward shock peak (Type I/Type II), and the forward shock-dominated cases without/with νm crossing the band (Type III/IV). We systematically investigate all of the Swift GRBs that have optical detection earlier than 500 s and find 3/63 Type I bursts (4.8%), 12/63 Type II bursts (19.0%), 30/63 Type III bursts (47.6%), 8/63 Type IV bursts (12.7%), and 10/63 Type III/IV bursts (15.9%). We perform Monte Carlo simulations to constrain model parameters in order to reproduce the observations. We find that the favored value of the magnetic equipartition parameter in the forward shock ({ɛ }B{{f}}) ranges from 10-6 to 10-2, and the reverse-to-forward ratio of ɛB ({{R}}B) is about 100. The preferred electron equipartition parameter {ɛ }{{e}}{{r},{{f}}} value is 0.01, which is smaller than the commonly assumed value, e.g., 0.1. This could mitigate the so-called “efficiency problem” for the internal shock model, if ɛe during the prompt emission phase (in the internal shocks) is large (say, ˜0.1). The preferred {{R}}B value is in agreement with the results in previous works that indicate a moderately magnetized baryonic jet for GRBs.

Not Just Fresh and Altered Basalt: Shocked Soil and Shocked Baked Zones Show the Collective Effects of Alteration and Shock

NASA Astrophysics Data System (ADS)

Wright, S. P.

2017-07-01

Besides shocked versions of both fresh and several types of altered basalt, shocked soils and baked zones found in Lonar Crater ejecta are examined to unravel the combined effects of alteration, shock, and then post-shock alteration of impact glass.

Structural and chemical alteration of crystalline olivine under low energy He+ irradiation

NASA Astrophysics Data System (ADS)

Demyk, K.; Carrez, Ph.; Leroux, H.; Cordier, P.; Jones, A. P.; Borg, J.; Quirico, E.; Raynal, P. I.; d'Hendecourt, L.

2001-03-01

We present the results of irradiation experiments on crystalline olivine with He+ ions at energies of 4 and 10 keV and fluences varying from 5 1016 to 1018 ions/cm2. The aim of these experiments is to simulate ion implantation into interstellar grains in shocks in the ISM. Irradiated samples were analysed by transmission electron microscopy (TEM). The irradiation causes the amorphization of the olivine, at all He+ fluences considered. The thickness of the amorphized region is 40 +/- 15 nm and 90 +/- 10 nm for the 4 keV and 10 keV experiments, respectively. The amorphization of the olivine occurs in conjunction with an increase in the porosity of the material due to the formation of bubbles. In addition, the amorphized layer is deficient in oxygen and magnesium. We find that the O/Si and Mg/Si ratios decrease as the He+ fluence increases. These experiments show that the irradiation of dust in supernova shocks can efficiently alter the dust structure and composition. Our result are consistent with the lack of crystalline silicates in the interstellar medium and also with the compositional evolution observed from olivine-type silicates around evolved stars to pyroxene-type silicates around protostars.

Ion Ramp Structure of Bow shocks and Interplanetary Shocks: Differences and Similarities

NASA Astrophysics Data System (ADS)

Goncharov, O.; Safrankova, J.; Nemecek, Z.; Koval, A.; Szabo, A.; Prech, L.; Zastenker, G. N.; Riazantseva, M.

2017-12-01

Collisionless shocks play a significant role in the solar wind interaction with the Earth. Fast forward shocks driven by coronal mass ejections or by interaction of fast and slow solar wind streams can be encountered in the interplanetary space, whereas the bow shock is a standing fast reverse shock formed by an interaction of the supersonic solar wind with the Earth magnetic field. Both types of shocks are responsible for a transformation of a part of the energy of the directed solar wind motion to plasma heating and to acceleration of reflected particles to high energies. These processes are closely related to the shock front structure. In present paper, we compares the analysis of low-Mach number fast forward interplanetary shocks registered in the solar wind by the DSCOVR, WIND, and ACE with observations of bow shock crossings observed by the Cluster, THEMIS, MMS, and Spektr-R spacecraft. An application of the high-time resolution data facilitates further discussion on formation mechanisms of both types of shocks.

Combined Measurement of Soluble ST2 and Amino-Terminal Pro-B-Type Natriuretic Peptide Provides Early Assessment of Severity in Cardiogenic Shock Complicating Acute Coronary Syndrome.

PubMed

Tolppanen, Heli; Rivas-Lasarte, Mercedes; Lassus, Johan; Sadoune, Malha; Gayat, Etienne; Pulkki, Kari; Arrigo, Mattia; Krastinova, Evguenia; Sionis, Alessandro; Parissis, John; Spinar, Jindrich; Januzzi, James; Harjola, Veli-Pekka; Mebazaa, Alexandre

2017-07-01

Mortality in cardiogenic shock complicating acute coronary syndrome is high, and objective risk stratification is needed for rational use of advanced therapies such as mechanical circulatory support. Traditionally, clinical variables have been used to judge risk in cardiogenic shock. The aim of this study was to assess the added value of serial measurement of soluble ST2 and amino-terminal pro-B-type natriuretic peptide to clinical parameters for risk stratification in cardiogenic shock. CardShock (www.clinicaltrials.gov NCT01374867) is a prospective European multinational study of cardiogenic shock. The main study introduced CardShock risk score, which is calculated from seven clinical variables at baseline, and was associated with short-term mortality. Nine tertiary care university hospitals. Patients with cardiogenic shock caused by acute coronary syndrome (n=145). In this substudy, plasma samples from the study patients were analyzed at eight time points during the ICU or cardiac care unit stay. Additional prognostic value of the biomarkers was assessed with incremental discrimination improvement. The combination of soluble ST2 and amino-terminal pro-B-type natriuretic peptide showed excellent discrimination for 30-day mortality (area under the curve, 0.77 at 12 hr up to 0.93 at 5-10 d after cardiogenic shock onset). At 12 hours, patients with both biomarkers elevated (soluble ST2, ≥ 500 ng/mL and amino-terminal pro-B-type natriuretic peptide, ≥ 4,500 ng/L) had higher 30-day mortality (79%) compared to those with one or neither biomarkers elevated (31% or 10%, respectively; p < 0.001). Combined measurement of soluble ST2 and amino-terminal pro-B-type natriuretic peptide at 12 hours added value to CardShock risk score, correctly reclassifying 11% of patients. The combination of results for soluble ST2 and amino-terminal pro-B-type natriuretic peptide provides early risk assessment beyond clinical variables in patients with acute coronary syndrome-related cardiogenic shock and may help therapeutic decision making in these patients.

Comparison Between Surf and Multi-Shock Forest Fire High Explosive Burn Models

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

Greenfield, Nicholas Alexander

PAGOSA1 has several different burn models used to model high explosive detonation. Two of these, Multi-Shock Forest Fire and Surf, are capable of modeling shock initiation. Accurately calculating shock initiation of a high explosive is important because it is a mechanism for detonation in many accident scenarios (i.e. fragment impact). Comparing the models to pop-plot data give confidence that the models are accurately calculating detonation or lack thereof. To compare the performance of these models, pop-plots2 were created from simulations where one two cm block of PBX 9502 collides with another block of PBX 9502.

Shock modon: a new type of coherent structure in rotating shallow water.

PubMed

Lahaye, Noé; Zeitlin, Vladimir

2012-01-27

We show that a new type of coherent structure, a shock modon, exists in a rotating shallow water model at large Rossby numbers. It is a combination of an asymmetric vortex dipole with a stationary hydraulic jump. The structure is long living, despite the energy dissipation by the hydraulic jump, and moving along a circular path. Collisions of shock modons can be elastic, or lead to formation of shock tripoles.

Glucose Starvation Alters Heat Shock Response, Leading to Death of Wild Type Cells and Survival of MAP Kinase Signaling Mutant

PubMed Central

Higgins, LeeAnn; Markowski, Todd; Brambl, Robert

2016-01-01

A moderate heat shock induces Neurospora crassa to synthesize large quantities of heat shock proteins that are protective against higher, otherwise lethal temperatures. However, wild type cells do not survive when carbohydrate deprivation is added to heat shock. In contrast, a mutant strain defective in a stress-activated protein kinase does survive the combined stresses. In order to understand the basis for this difference in survival, we have determined the relative levels of detected proteins in the mutant and wild type strain during dual stress, and we have identified gene transcripts in both strains whose quantities change in response to heat shock or dual stress. These data and supportive experimental evidence point to reasons for survival of the mutant strain. By using alternative respiratory mechanisms, these cells experience less of the oxidative stress that proves damaging to wild type cells. Of central importance, mutant cells recycle limited resources during dual stress by undergoing autophagy, a process that we find utilized by both wild type and mutant cells during heat shock. Evidence points to inappropriate activation of TORC1, the central metabolic regulator, in wild type cells during dual stress, based upon behavior of an additional signaling mutant and inhibitor studies. PMID:27870869

Lack of muco-cutaneous signs of toxic shock syndrome when T cells are absent: S.aureus shock in immunodeficient adults with multiple myeloma

PubMed Central

KAMEL, N S; BANKS, M C; DOSIK, A; URSEA, D; YARILINA, A A; POSNETT, D N

2002-01-01

Staphylococcal toxic shock syndrome (TSS) is an acute life threatening disease. The diagnosis can be made clinically based on diagnostic criteria. The clinical manifestations are caused in large part by the release of high levels of T-cell-derived cytokines as a result of potent toxins, also called superantigens (SAg), produced by Staphylococcus aureus, but it is not clear which clinical symptoms/signs are strictly T-cell dependent. Here, we report on three adults with multiple myeloma (MM) presenting with S. aureus sepsis/shock, and two patients with typical TSS. The MM patients had compromised humoral immunity because of depression of normal immunoglobulin (Ig) levels at the expense of the M protein. In addition, their T cells were absent due to high dose chemotherapy initiated for bone marrow transplantation. The MM cases lacked mucosal hyperemia, erythroderma and desquamation, but were otherwise indistinguishable from the TSS cases. All patients grew S. aureus and in each case, SAg genes were detected by PCR. In several cases, the plasma contained biological SAg activity resulting in Vβ specific proliferation of indicator T cells in vitro. The same specific activity was observed with the supernatant fluids of S. aureus broth cultures from the respective bacterial isolates. This confirms the presence of bio-active toxins in the plasma but did not lead to full blown TSS when T cells were lacking. Thus, S.aureus sepsis/shock can be clinically distinguished from typical TSS, and we suggest that muco-cutaneous manifestations of TSS are the most telling signs of massive T-cell-dependent cytokine release. PMID:12033193

The Western North American Cretaceous-Tertiary (K-T) boundary interval and its content of shock-metamorphosed minerals: Implications concerning the K-T boundary impact-extinction theory

NASA Technical Reports Server (NTRS)

Izett, G. A.

1988-01-01

At 20 sites in the Raton Basin of Colorado and New Mexico, and at several other sites in Wyoming, Montana, and Canada, a pair of claystone units, an Ir abundance anomaly, and a concentration of shock-metamorphosed minerals mark the palynological K-T boundary. The K-T boundary claystone, which is composed of kaolinite and small amounts of illite/smectite mixed-layer clay, is similar in most respects to kaolinite tonstein layers in coal beds. At some, but not all, K-T boundary localities, the boundary claystone contains solid kaolinite and hollow and solid goyazite spherules, 0.05 to 1.2 mm in diameter. The upper unit, the K-T boundary impact layer, consists chiefly of kaolinite and various amounts of illite/smectite mixed-layer clay. The impact layer and boundary claystone are similar chemically, except that the former has slightly more Fe, K, Ba, Cr, Cu, Li, V, and Zn than the latter. The facts that the boundary claystone and impact layer contain anomalous amounts of Ir, comprise a stratigraphic couplet at Western North American sites, and form thin, discrete layers, similar to air-fall units (volcanic or impact), suggest that the claystone units are of impact origin. Significantly, the impact layer contains as much as 2 percent clastic mineral grains, about 30 percent of which contain multiple sets of shock lamellae. Only one such concentration of shocked minerals has been found near the K-T boundary. The type of K-T boundary shock-metamorphosed materials (quartzite and metaquartzite) in the impact layer and the lack of shock lamellae in quartz and feldspar of pumice lapilli and granitic xenoliths in air-fall pumice units of silicic tuffs, such as the Bishop Tuff, eliminate the possibility that the shock-metamorphosed minerals in the K-T impact layer are of volcanic origin. The global size distribution and abundance of shock-metamorphosed mineral grains suggest that the K-T impact occurred in North America.

Molecular determinants for a cardiovascular collapse in anthrax

PubMed Central

Brojatsch, Jurgen; Casadevall, Arturo; Goldman, David L.

2015-01-01

Bacillus anthracis releases two bipartite proteins, lethal toxin and edema factor, that contribute significantly to the progression of anthrax-associated shock. As blocking the anthrax toxins prevents disease, the toxins are considered the main virulence factors of the bacterium. The anthrax bacterium and the anthrax toxins trigger multiorgan failure associated with enhanced vascular permeability, hemorrhage and cardiac dysfunction in animal challenge models. A recent study using mice that either lacked the anthrax toxin receptor in specific cells and corresponding mice expressing the receptor in specific cell types demonstrated that cardiovascular cells are critical for disease mediated by anthrax lethal toxin. These studies are consistent with involvement of the cardiovascular system, and with an increase of cardiac failure markers observed in human anthrax and in animal models using B. anthracis and anthrax toxins. This review discusses the current state of knowledge regarding the pathophysiology of anthrax and tries to provide a mechanistic model and molecular determinants for the circulatory shock in anthrax. PMID:24389148

Coronal Mass Ejection-driven Shocks and the Associated Sudden Commencements-sudden Impulses

NASA Technical Reports Server (NTRS)

Veenadhari, B.; Selvakumaran, R.; Singh, Rajesh; Maurya, Ajeet K.; Gopalswamy, N.; Kumar, Sushil; Kikuchi, T.

2012-01-01

Interplanetary (IP) shocks are mainly responsible for the sudden compression of the magnetosphere, causing storm sudden commencement (SC) and sudden impulses (SIs) which are detected by ground-based magnetometers. On the basis of the list of 222 IP shocks compiled by Gopalswamy et al., we have investigated the dependence of SC/SIs amplitudes on the speed of the coronal mass ejections (CMEs) that drive the shocks near the Sun as well as in the interplanetary medium. We find that about 91% of the IP shocks were associated with SC/SIs. The average speed of the SC/SI-associated CMEs is 1015 km/s, which is almost a factor of 2 higher than the general CME speed. When the shocks were grouped according to their ability to produce type II radio burst in the interplanetary medium, we find that the radio-loud (RL) shocks produce a much larger SC/SI amplitude (average approx. 32 nT) compared to the radio-quiet (RQ) shocks (average approx. 19 nT). Clearly, RL shocks are more effective in producing SC/SIs than the RQ shocks. We also divided the IP shocks according to the type of IP counterpart of interplanetary CMEs (ICMEs): magnetic clouds (MCs) and nonmagnetic clouds. We find that the MC-associated shock speeds are better correlated with SC/SI amplitudes than those associated with non-MC ejecta. The SC/SI amplitudes are also higher for MCs than ejecta. Our results show that RL and RQ type of shocks are important parameters in producing the SC/SI amplitude.

Energetic storm particle events in coronal mass ejection-driven shocks

NASA Astrophysics Data System (ADS)

Mäkelä, P.; Gopalswamy, N.; Akiyama, S.; Xie, H.; Yashiro, S.

2011-08-01

We investigate the variability in the occurrence of energetic storm particle (ESP) events associated with shocks driven by coronal mass ejections (CMEs). The interplanetary shocks were detected during the period from 1996 to 2006. First, we analyze the CME properties near the Sun. The CMEs with an ESP-producing shock are faster ($\\langle$VCME$\\rangle$ = 1088 km/s) than those driving shocks without an ESP event ($\\langle$VCME$\\rangle$ = 771 km/s) and have a larger fraction of halo CMEs (67% versus 38%). The Alfvénic Mach numbers of shocks with an ESP event are on average 1.6 times higher than those of shocks without. We also contrast the ESP event properties and frequency in shocks with and without a type II radio burst by dividing the shocks into radio-loud (RL) and radio-quiet (RQ) shocks, respectively. The shocks seem to be organized into a decreasing sequence by the energy content of the CMEs: RL shocks with an ESP event are driven by the most energetic CMEs, followed by RL shocks without an ESP event, then RQ shocks with and without an ESP event. The ESP events occur more often in RL shocks than in RQ shocks: 52% of RL shocks and only ˜33% of RQ shocks produced an ESP event at proton energies above 1.8 MeV; in the keV energy range the ESP frequencies are 80% and 65%, respectively. Electron ESP events were detected in 19% of RQ shocks and 39% of RL shocks. In addition, we find that (1) ESP events in RQ shocks are less intense than those in RL shocks; (2) RQ shocks with ESP events are predominately quasi-perpendicular shocks; (3) their solar sources are located slightly to the east of the central meridian; and (4) ESP event sizes show a modest positive correlation with the CME and shock speeds. The observation that RL shocks tend to produce more frequently ESP events with larger particle flux increases than RQ shocks emphasizes the importance of type II bursts in identifying solar events prone to producing high particle fluxes in the near-Earth space. However, the trend is not definitive. If there is no type II emission, an ESP event is less likely but not absent. The variability in the probability and size of ESP events most likely reflects differences in the shock formation in the low corona and changes in the properties of the shocks as they propagate through interplanetary space and the escape efficiency of accelerated particles from the shock front.

Does Explosive Nuclear Burning Occur in Tidal Disruption Events of White Dwarfs by Intermediate-mass Black Holes?

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

Tanikawa, Ataru; Sato, Yushi; Hachisu, Izumi

We investigate nucleosynthesis in tidal disruption events (TDEs) of white dwarfs (WDs) by intermediate-mass black holes. We consider various types of WDs with different masses and compositions by means of three-dimensional (3D) smoothed particle hydrodynamics (SPH) simulations. We model these WDs with different numbers of SPH particles, N , from a few 10{sup 4} to a few 10{sup 7} in order to check mass resolution convergence, where SPH simulations with N > 10{sup 7} (or a space resolution of several 10{sup 6} cm) have unprecedentedly high resolution in this kind of simulation. We find that nuclear reactions become less activemore » with increasing N and that these nuclear reactions are excited by spurious heating due to low resolution. Moreover, we find no shock wave generation. In order to investigate the reason for the absence of a shock wave, we additionally perform one-dimensional (1D) SPH and mesh-based simulations with a space resolution ranging from 10{sup 4} to 10{sup 7} cm, using a characteristic flow structure extracted from the 3D SPH simulations. We find shock waves in these 1D high-resolution simulations, one of which triggers a detonation wave. However, we must be careful of the fact that, if the shock wave emerged in an outer region, it could not trigger the detonation wave due to low density. Note that the 1D initial conditions lack accuracy to precisely determine where a shock wave emerges. We need to perform 3D simulations with ≲10{sup 6} cm space resolution in order to conclude that WD TDEs become optical transients powered by radioactive nuclei.« less

Mild deficits in mice lacking pituitary adenylate cyclase-activating polypeptide receptor type 1 (PAC1) performing on memory tasks.

PubMed

Sauvage, M; Brabet, P; Holsboer, F; Bockaert, J; Steckler, T

2000-12-08

Pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptor subtype 1 (PAC1) have been suggested to play a role in the modulation of learning and memory. However, behavioral evidence for altered mnemonic function due to altered PAC1 activity is missing. Therefore, the role of PAC1 in learning and memory was studied in mouse mutants lacking this receptor (PAC1 knock-out mice), tested in water maze two-choice spatial discrimination, one-trial contextual and cued fear conditioning, and multiple-session contextual discrimination. Water maze spatial discrimination was unaffected in PAC1 mutants, while a mild deficit was observed in multiple session contextual discrimination in PAC1 knock-out mice. Furthermore, PAC1 knock-out mice were able to learn the association between context and shock in one-trial contextual conditioning, but showed faster return to baseline than wild-type mice. Thus, the effects of PAC1 knock-out on modulating performance in these tasks were subtle and suggest that PAC1 only plays a limited role in learning and memory.

2-(4-(Biphenyl-4-ylamino)-6-chloropyrimidin-2-ylthio)octanoic acid (HZ52) – a novel type of 5-lipoxygenase inhibitor with favourable molecular pharmacology and efficacy in vivo

PubMed Central

Greiner, C; Hörnig, C; Rossi, A; Pergola, C; Zettl, H; Schubert-Zsilavecz, M; Steinhilber, D; Sautebin, L; Werz, O

2011-01-01

BACKGROUND AND PURPOSE 5-Lipoxygenase (5-LO) is the key enzyme in the biosynthesis of pro-inflammatory leukotrienes (LTs) representing a potential target for pharmacological intervention with inflammation and allergic disorders. Although many LT synthesis inhibitors are effective in simple in vitro test systems, they frequently fail in vivo due to lack of efficacy. Here, we attempted to assess the pharmacological potential of the previously identified 5-LO inhibitor 2-(4-(biphenyl-4-ylamino)-6-chloropyrimidin-2-ylthio)octanoic acid (HZ52). EXPERIMENTAL APPROACH We evaluated the efficacy of HZ52 in vivo using carrageenan-induced pleurisy in rats and platelet-activating factor (PAF)-induced lethal shock in mice. We also characterized 5-LO inhibition by HZ52 at the cellular and molecular level in comparison with other types of 5-LO inhibitor, that is, BWA4C, ZM230487 and hyperforin. KEY RESULTS HZ52, 1.5 mg·kg−1 i.p., prevented carrageenan-induced pleurisy accompanied by reduced LTB4 levels and protected mice (10 mg·kg−1, i.p.) against PAF-induced shock. Detailed analysis in cell-based and cell-free assays revealed that inhibition of 5-LO by HZ52 (i) does not depend on radical scavenging properties and is reversible; (ii) is not impaired by an increased peroxide tone or by elevated substrate concentrations; and (iii) is little affected by the cell stimulus or by phospholipids, glycerides, membranes or Ca2+. CONCLUSIONS AND IMPLICATIONS HZ52 is a promising new type of 5-LO inhibitor with efficacy in vivo and with a favourable pharmacological profile. It possesses a unique 5-LO inhibitory mechanism different from classical 5-LO inhibitors and seemingly lacks the typical disadvantages of former classes of LT synthesis blockers. PMID:21506958

Studies of aerothermal loads generated in regions of shock/shock interaction in hypersonic flow

NASA Technical Reports Server (NTRS)

Holden, Michael S.; Moselle, John R.; Lee, Jinho

1991-01-01

Experimental studies were conducted to examine the aerothermal characteristics of shock/shock/boundary layer interaction regions generated by single and multiple incident shocks. The presented experimental studies were conducted over a Mach number range from 6 to 19 for a range of Reynolds numbers to obtain both laminar and turbulent interaction regions. Detailed heat transfer and pressure measurements were made for a range of interaction types and incident shock strengths over a transverse cylinder, with emphasis on the 3 and 4 type interaction regions. The measurements were compared with the simple Edney, Keyes, and Hains models for a range of interaction configurations and freestream conditions. The complex flowfields and aerothermal loads generated by multiple-shock impingement, while not generating as large peak loads, provide important test cases for code prediction. The detailed heat transfer and pressure measurements proved a good basis for evaluating the accuracy of simple prediction methods and detailed numerical solutions for laminar and transitional regions or shock/shock interactions.

THE POSSIBLE ROLE OF CORONAL STREAMERS AS MAGNETICALLY CLOSED STRUCTURES IN SHOCK-INDUCED ENERGETIC ELECTRONS AND METRIC TYPE II RADIO BURSTS

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

Kong, Xiangliang; Chen, Yao; Feng, Shiwei

2015-01-10

Two solar type II radio bursts, separated by ∼24 hr in time, are examined together. Both events are associated with coronal mass ejections (CMEs) erupting from the same active region (NOAA 11176) beneath a well-observed helmet streamer. We find that the type II emissions in both events ended once the CME/shock fronts passed the white-light streamer tip, which is presumably the magnetic cusp of the streamer. This leads us to conjecture that the closed magnetic arcades of the streamer may play a role in electron acceleration and type II excitation at coronal shocks. To examine such a conjecture, we conduct a test-particle simulationmore » for electron dynamics within a large-scale partially closed streamer magnetic configuration swept by a coronal shock. We find that the closed field lines play the role of an electron trap via which the electrons are sent back to the shock front multiple times and therefore accelerated to high energies by the shock. Electrons with an initial energy of 300 eV can be accelerated to tens of keV concentrating at the loop apex close to the shock front with a counter-streaming distribution at most locations. These electrons are energetic enough to excite Langmuir waves and radio bursts. Considering the fact that most solar eruptions originate from closed field regions, we suggest that the scenario may be important for the generation of more metric type IIs. This study also provides an explanation of the general ending frequencies of metric type IIs at or above 20-30 MHz and the disconnection issue between metric and interplanetary type IIs.« less

[Biochemical indicators of anaphylactic shock and the application in forensic medicine].

PubMed

Mi, Li; Chen, Jie; Gao, Wei-Min; Du, Zhong-Bo; Cao, Zhi-Peng; Zhang, Yuan; Zhu, Bao-Li

2014-04-01

Fatal anaphylactic shock is common in forensic practice. However, it is difficult to diagnose for lacking specific pathological and morphologic changes in forensic autopsy. The application of some biochemical indicators is of great significance. This paper reviews the biological characteristics of some biochemical indicators and detection methods. The forensic application, problems and prospects of these indicators are also introduced in details. The stable biochemical indicators, IgE, tryptase and chymase, show great potential and advantages in the identification of fatal anaphylactic shock in forensic medicine.

Shock wave experiments on gallium

NASA Astrophysics Data System (ADS)

Jensen, Brian; Branch, Brittany; Cherne, Frank

2017-06-01

Gallium exhibits a complex phase diagram with multiple solid phases, an anomalous melt boundary, and a low-temperature melt transition making it a suitable material for shock wave studies focused on multiphase properties including kinetics and strength. Apart from high-pressure shock wave data that exists for the liquid phase, there is a clear lack of data in the low-pressure regime where much of the complexity in the phase diagram exists. In this work, a series of shock wave experiments were performed to begin examining the low-pressure region of the phase diagram. Additional data on a gallium alloy, which remains liquid at room temperature, will be presented and compared to data available for pure gallium (LA-UR-17-21449).

The Curious Events Leading to the Theory of Shock Waves

NASA Technical Reports Server (NTRS)

Salas, Manuel D.

2006-01-01

We review the history of the development of the modern theory of shock waves. Several attempts at an early-theory quickly collapsed for lack of foundations in mathematics and thermodynamics. It is not until the works of Rankine and later Hugoniot that a full theory is established. Rankine is the first to show that within the shock a non-adiabatic process must occur. Hugoniot showed that in the absence of viscosity and heat conduction conservation of energy implies conservation of entropy in smooth regions and a jump in entropy across a shock. Even after the theory is fully developed, old notions continue to pervade the literature well into the early part of the 20th Century.

Flow visualization of unsteady phenomena in the hypersonic regime using high-speed video camera

NASA Astrophysics Data System (ADS)

Hashimoto, Tokitada; Saito, Tsutomu; Takayama, Kazuyoshi

2004-02-01

Flows over double cones and wedges featured with a large shock induced separation zone are representative of many parts of hypersonic vehicle geometries. To be practically important at shock interactions is phenomena that the shock wave produced from another objects carries out incidence to bow shock around a blunt body in the hypersonic flows, the two shock waves interact each other and various shock interactions occur according to the intensity of the shock wave and depending on the case of the local maximum of pressure and heat flux is locally produced on the body surface. The six types of shock interactions are classified, and particularly in the Type IV, a shear layer generated from the intersection of the two shock reached on the body surface, and locally anomalous pressure increase and aerodynamic heating occurred experimentally. In the present study, unsteady shock oscillations and periodically separation flows were visualized by means of high-speed video camera. Particularly, sequential observations with combination of schlieren methods are very effective because of flow unsteadiness.

Experimentally Shock-loaded Anhydrite: Unit-Cell Dimensions, Microstrain and Domain Size from X-Ray Diffraction

NASA Technical Reports Server (NTRS)

Skala, R.; Hoerz, F.

2003-01-01

Cretaceous Tertiary (K/T) boundary is traditionally associated with one of the most dramatic mass extinctions in the Earth history. A number of killing mechanisms have been suggested to contribute to the widespread extinctions of Cretaceous biota at this boundary, including severe, global deterioration of the atmosphere and hydrosphere from the shock-induced release of CO2 and SO(x) from carbonate- and sulfate-bearing target rocks, respectively. Recently carried out calculations revealed that the global warming caused by CO2 release was considerably less important than the cooling due to SO(x) gases release during the Chicxulub impact event. Considering apparent potential importance of the response of sulfates to the shock metamorphism, relative lack of the data on shock behavior of sulfates as well as some general difficulties encountered during thermodynamic modeling of the shock-induced CO2 loss from carbonates we subjected anhydrite to a series of shock experiments designed for complete recovery of the shocked material. We report here on the detail X-ray diffraction analysis of seven samples that were subjected to experimental shock-loading from 10 to 65 GPa.

Development of low-shock pyrotechnic separation nuts. [design performance of flight type nuts

NASA Technical Reports Server (NTRS)

Bement, L. J.; Neubert, V. H.

1973-01-01

Performance demonstrations and comparisons were made on six flight type pyrotechnic separation nut designs, two of which are standard designs in current use, and four of which were designed to produce low shock on actuation. Although the shock performances of the four low shock designs are considerably lower than the standard designs, some penalties may be incurred in increased volume, weight, or complexity. These nuts, and how they are installed, can significantly influence the pyrotechnic shock created in spacecraft structures. A high response monitoring system has been developed and demonstrated to provide accurate performance comparisons for pyrotechnic separation nuts.

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

Kubouchi, Masatoshi; Hojo, Hidemitsu

The thermal shock resistance of epoxy resin specimens toughened with carboxy-terminated poly(butadiene-acrylonitrile) (CTBN) and poly-glycol were tested using a new notched disk-type specimen. The new thermal shock testing method consists of quenching a notched disk-type specimen and applying a theoretical analysis to the test results to determine crack propagation conditions. For both toughened epoxy resins, this test method evaluated improvements in thermal shock resistance. The thermal shock resistance of epoxy resin toughened with CTBN exhibited a maximum at a 35 parts per hundred resin content of CTBN. The epoxy resin toughened with polyglycol exhibited improved thermal shock resistance with increasingmore » glycol content. 7 refs., 14 figs., 1 tab.« less

Lucky in Life, Unlucky in Love? The Effect of Random Income Shocks on Marriage and Divorce

ERIC Educational Resources Information Center

Hankins, Scott; Hoekstra, Mark

2011-01-01

Economists have long been interested in the extent to which economic resources affect decisions to marry and divorce. However, this issue has been difficult to address empirically due to a lack of exogenous income shocks. We overcome this problem by exploiting the randomness of the Florida Lottery and comparing recipients of large prizes to those…

Chemical projectile-target interaction during hypervelocity cratering experiments (MEMIN project).

NASA Astrophysics Data System (ADS)

Ebert, M.; Hecht, L.; Deutsch, A.; Kenkmann, T.

2012-04-01

The detection and identification of meteoritic components in impact-derived rocks are of great value for confirming an impact origin and reconstructing the type of extraterrestrial material that repeatedly stroke the Earth during geologic evolution [1]. However, little is known about processes that control the projectile distribution into the various impactites that originate during the cratering and excavation process, and inter-element fractionation between siderophile elements during impact cratering. In the context of the MEMIN project, cratering experiments have been performed using spheres of Cr-V-Co-Mo-W-rich steel and of the iron meteorite Campo del Cielo (IAB) as projectiles accelerated to about 5 km/s, and blocks of Seeberger sandstone as target. The experiments were carried out at the two-stage acceleration facilities of the Fraunhofer Ernst-Mach-Institute (Freiburg). Our results are based on geochemical analyses of highly shocked ejecta material. The ejecta show various shock features including multiple sets of planar deformations features (PDF) in quartz, diaplectic quartz, and partial melting of the sandstone. Melting is concentrated in the phyllosilicate-bearing sandstone matrix but involves quartz, too. Droplets of molten projectile have entered the low-viscosity sandstone melt but not quartz glass. Silica-rich sandstone melts are enriched in the elements that are used to trace the projectile, like Fe, Ni, Cr, Co, and V (but no or little W and Mo). Inter-element ratios of these "projectile" tracer elements within the contaminated sandstone melt may be strongly modified from the original ratios in the projectiles. This fractionation most likely result from variation in the lithophile or siderophile character and/or from differences in reactivity of these tracer elements with oxygen [2] during interaction of metal melt with silicate melt. The shocked quartz with PDF is also enriched in Fe and Ni (experiment with a meteorite iron projectile) and in Fe, Cr, Co and V (experiment with the steel projectile). An enrichment of W and Mo in the shocked quartzes could not be observed. It is suggested that two types of geochemical mixing processes between projectile and target occur during the impact process: (i) After shock compression with formation of PDF in Qtz and diaplectic quartz glass, up to about 1 % of projectile matter is added to these phases without detectable fractionation between the meteoritic tracer elements (except W and Mo). We suggest that projectile material was introduced to shocked quartz from a metallic vapour phase, which was formed near the projectile-target interface. The lack of W and Mo enrichment in shocked target material probably results from the relatively high melting and boiling points of these elements. (ii) In addition heterogeneous melting of sandstone and projectile and subsequent mixing of both melts inter-element fractionation occurred according to the chemical properties of the elements. Fractionation processes similar to our type (ii) are known from natural impactites [3]. We acknowledge support by the German Science Foundation (DFG FOR 887)

A Temperature-Independent Cold-Shock Protein Homolog Acts as a Virulence Factor in Xylella fastidiosa.

PubMed

Burbank, Lindsey P; Stenger, Drake C

2016-05-01

Xylella fastidiosa, causal agent of Pierce's disease (PD) of grapevine, is a fastidious organism that requires very specific conditions for replication and plant colonization. Cold temperatures reduce growth and survival of X. fastidiosa both in vitro and in planta. However, little is known regarding physiological responses of X. fastidiosa to temperature changes. Cold-shock proteins (CSP), a family of nucleic acid-binding proteins, act as chaperones facilitating translation at low temperatures. Bacterial genomes often encode multiple CSP, some of which are strongly induced following exposure to cold. Additionally, CSP contribute to the general stress response through mRNA stabilization and posttranscriptional regulation. A putative CSP homolog (Csp1) with RNA-binding activity was identified in X. fastidiosa Stag's Leap. The csp1 gene lacked the long 5' untranslated region characteristic of cold-inducible genes and was expressed in a temperature-independent manner. As compared with the wild type, a deletion mutant of csp1 (∆csp1) had decreased survival rates following cold exposure and salt stress in vitro. The deletion mutant also was significantly less virulent in grapevine, as compared with the wild type, in the absence of cold stress. These results suggest an important function of X. fastidiosa Csp1 in response to cellular stress and during plant colonization.

Optical distortion in the field of a lithotripter shock wave

NASA Astrophysics Data System (ADS)

Carnell, M. T.; Emmony, D. C.

1995-10-01

The schlieren observation of cavitation phenomena produced in the tail of a lithotripter shock wave has indicated the presence of some interesting features. The images produced appear to indicate that cavitation transients in the field of a shock wave propagate nonsymmetrically; this is not the case. The apparent lack of symmetry exhibited by the primary cavitation transients is due to a complex optical lensing effect, which is brought about by the change in refractive index associated with the pressure profile of the shock wave. Objects seen through or immersed in the shock-wave field of an electromagnetic acoustic transducer, such as cavitation, appear highly distorted because of the strong positive and negative lensing effects of the compression and rarefaction cycles of the shock wave. A modification of the schlieren technique called the scale method has been used to model the distortion introduced by the shock wave and consequently explain the cavitation distortion. The technique has also been used to quantitatively analyze and partially reconstruct the lithotripter shock wave. The combination of schlieren and scale imaging gives more information about the refractive index field and therefore the shock-wave structure itself.

A New Method to Comprehensively Diagnose Shock Waves in the Solar Atmosphere Based on Simultaneous Spectroscopic and Imaging Observations

NASA Astrophysics Data System (ADS)

Ruan, Wenzhi; Yan, Limei; He, Jiansen; Zhang, Lei; Wang, Linghua; Wei, Yong

2018-06-01

Shock waves are believed to play an important role in plasma heating. The shock-like temporal jumps in radiation intensity and Doppler shift have been identified in the solar atmosphere. However, a quantitative diagnosis of the shocks in the solar atmosphere is still lacking, seriously hindering the understanding of shock dissipative heating of the solar atmosphere. Here, we propose a new method to realize the goal of the shock quantitative diagnosis, based on Rankine–Hugoniot equations and taking the advantages of simultaneous imaging and spectroscopic observations from, e.g., IRIS (Interface Region Imaging Spectrograph). Because of this method, the key parameters of shock candidates can be derived, such as the bulk velocity and temperature of the plasma in the upstream and downstream, the propagation speed and direction. The method is applied to the shock candidates observed by IRIS, and the overall characteristics of the shocks are revealed quantitatively for the first time. This method is also tested with the help of forward modeling, i.e., virtual observations of simulated shocks. The parameters obtained from the method are consistent with the parameters of the shock formed in the model and are independent of the viewing direction. Therefore, the method we proposed here is applicable to the quantitative and comprehensive diagnosis of the observed shocks in the solar atmosphere.

Spherical shock waves in general relativity

NASA Astrophysics Data System (ADS)

Nutku, Y.

1991-11-01

We present the metric appropriate to a spherical shock wave in the framework of general relativity. This is a Petrov type-N vacuum solution of the Einstein field equations where the metric is continuous across the shock and the Riemann tensor suffers a step-function discontinuity. Spherical gravitational waves are described by type-N Robinson-Trautman metrics. However, for shock waves the Robinson-Trautman solutions are unacceptable because the metric becomes discontinuous in the Robinson-Trautman coordinate system. Other coordinate systems that have so far been introduced for describing Robinson-Trautman solutions also suffer from the same defect. We shall present the C0-form of the metric appropriate to spherical shock waves using Penrose's approach of identification with warp. Further extensions of Penrose's method yield accelerating, as well as coupled electromagnetic-gravitational shock-wave solutions.

Sequential N-Terminal Pro-B-Type Natriuretic Peptide and High-Sensitivity Cardiac Troponin Measurements During Albumin Replacement in Patients With Severe Sepsis or Septic Shock.

PubMed

Masson, Serge; Caironi, Pietro; Fanizza, Caterina; Carrer, Sara; Caricato, Anselmo; Fassini, Paola; Vago, Tarcisio; Romero, Marilena; Tognoni, Gianni; Gattinoni, Luciano; Latini, Roberto

2016-04-01

Myocardial dysfunction is a frequent complication in patients with severe sepsis and can worsen the prognosis. We investigated whether circulating biomarkers related to myocardial function and injury predicted outcome and were associated with albumin replacement. A multicenter, randomized clinical trial about albumin replacement in severe sepsis or septic shock (the Albumin Italian Outcome Sepsis trial). Forty ICUs in Italy. Nine hundred and ninety-five patients with severe sepsis or septic shock. Randomization to albumin and crystalloid solutions or crystalloid solutions alone. Plasma concentrations of N- terminal pro-B-type natriuretic peptide and high-sensitivity cardiac troponin T were measured 1, 2, and 7 days after enrollment. We tested the relationship of single marker measurements or changes over time with clinical events, organ dysfunctions, albumin replacement, and ICU or 90-day mortality in the overall population and after stratification by shock. N-terminal pro-B-type natriuretic peptide levels were abnormal in 97.4% of the patients and high-sensitivity cardiac troponin T in 84.5%, with higher concentrations in those with shock. After extensive adjustments, N-terminal pro-B-type natriuretic peptide concentrations predicted ICU or 90-day mortality, better than high-sensitivity cardiac troponin T. Early changes in N-terminal pro-B-type natriuretic peptide or high-sensitivity cardiac troponin T concentrations were independently associated with subsequent mortality in patients with shock. Patients given albumin had significantly higher N-terminal pro-B-type natriuretic peptide levels; in addition, early rise in N-terminal pro-B-type natriuretic peptide was associated with a better outcome in this subgroup. Circulating N-terminal pro-B-type natriuretic peptide and high-sensitivity cardiac troponin T are frequently elevated in severe sepsis or septic shock and have relevant prognostic value, which may be important in monitoring the clinical efficacy of supporting therapy.

Determining the standoff distance of the bow shock: Mach number dependence and use of models

NASA Technical Reports Server (NTRS)

Farris, M. H.; Russell, C. T.

1994-01-01

We explore the factors that determine the bow shock standoff distance. These factors include the parameters of the solar wind, as well as the size and shape of the obstacle. In this report we develop a semiempirical Mach number relation for the bow shock standoff distance in order to take into account the shock's behavior at low Mach numbers. This is done by determining which properties of the shock are most important in controlling the standoff distance and using this knowledge to modify the current Mach number relation. While the present relation has proven useful at higher Mach numbers, it has lacked effectiveness at the low Mach number limit. We also analyze the bow shock dependence upon the size and shape of the obstacle, noting that it is most appropriate to compare the standoff distance of the bow shock to the radius of curvature of the obstacle, as opposed to the distance from the focus of the object to the nose. Last, we focus our attention on the use of bow shock models in determining the standoff distance. We note that the physical behavior of the shock must correctly be taken into account, specifically the behavior as a function of solar wind dynamic pressure; otherwise, erroneous results can be obtained for the bow shock standoff distance.

Effect of heat shock on ultrastructure and calcium distribution in Lavandula pinnata L. glandular trichomes.

PubMed

Huang, S S; Kirchoff, B K; Liao, J P

2013-02-01

The effects of heat shock (HS) on the ultrastructure and calcium distribution of Lavandula pinnata secretory trichomes are examined using transmission electron microscopy and potassium antimonate precipitation. After 48-h HS at 40°C, plastids become distorted and lack stroma and osmiophilic deposits, the cristae of the mitochondria become indistinct, the endoplasmic reticulum acquires a chain-like appearance with ribosomes prominently attached to the lamellae, and the plasma and organelle membranes become distorted. Heat shock is associated with a decrease in calcium precipitates in the trichomes, while the number of precipitates increases in the mesophyll cells. Prolonged exposure to elevated calcium levels may be toxic to the mesophyll cells, while the lack of calcium in the glands cell may deprive them of the normal protective advantages of elevated calcium levels. The inequality in calcium distribution may result not only from uptake from the transpiration stream, but also from redistribution of calcium from the trichomes to the mesophyll cells.

Time- and fluid-sensitive resuscitation for hemodynamic support of children in septic shock: barriers to the implementation of the American College of Critical Care Medicine/Pediatric Advanced Life Support Guidelines in a pediatric intensive care unit in a developing world.

PubMed

Oliveira, Cláudio F; Nogueira de Sá, Flávio R; Oliveira, Débora S F; Gottschald, Adriana F C; Moura, Juliana D G; Shibata, Audrey R O; Troster, Eduardo J; Vaz, Flávio A C; Carcillo, Joseph A

2008-12-01

To analyze mortality rates of children with severe sepsis and septic shock in relation to time-sensitive fluid resuscitation and treatments received and to define barriers to the implementation of the American College of Critical Care Medicine/Pediatric Advanced Life Support guidelines in a pediatric intensive care unit in a developing country. Retrospective chart review and prospective analysis of septic shock treatment in a pediatric intensive care unit of a tertiary care teaching hospital. Ninety patients with severe sepsis or septic shock admitted between July 2002 and June 2003 were included in this study. Of the 90 patients, 83% had septic shock and 17% had severe sepsis; 80 patients had preexisting severe chronic diseases. Patients with septic shock who received less than a 20-mL/kg dose of resuscitation fluid in the first hour of treatment had a mortality rate of 73%, whereas patients who received more than a 40-mL/kg dose in the first hour of treatment had a mortality rate of 33% (P < 0.05). Patients treated less than 30 minutes after diagnosis of severe sepsis and septic shock had a significantly lower mortality rate (40%) than patients treated more than 60 minutes after diagnosis (P < 0.05). Controlling for the risk of mortality, early fluid resuscitation was associated with a 3-fold reduction in the odds of death (odds ratio, 0.33; 95% confidence interval, 0.13-0.85). The most important barriers to achieve adequate severe sepsis and septic shock treatment were lack of adequate vascular access, lack of recognition of early shock, shortage of health care providers, and nonuse of goals and treatment protocols. The mortality rate was higher for children older than 2 years, for those who received less than 40 mL/kg in the first hour, and for those whose treatment was not initiated in the first 30 minutes after the diagnosis of septic shock. The acknowledgment of existing barriers to a timely fluid administration and the establishment of objectives to overcome these barriers may lead to a more successful implementation of the American College of Critical Care Medicine guidelines and reduced mortality rates for children with septic shock in the developing world.

Intermediate shocks in three-dimensional magnetohydrodynamic bow-shock flows with multiple interacting shock fronts

PubMed

De Sterck H; Poedts

2000-06-12

Simulation results of three-dimensional (3D) stationary magnetohydrodynamic (MHD) bow-shock flows around perfectly conducting spheres are presented. For strong upstream magnetic field a new complex bow-shock flow topology arises consisting of two consecutive interacting shock fronts. It is shown that the leading shock front contains a segment of intermediate 1-3 shock type. This is the first confirmation in 3D that intermediate shocks, which were believed to be unphysical for a long time, can be formed and can persist for small-dissipation MHD in a realistic flow configuration.

Operational, Real-Time, Sun-to-Earth Interplanetary Shock Predictions During Solar Cycle 23

NASA Astrophysics Data System (ADS)

Fry, C. D.; Dryer, M.; Sun, W.; Deehr, C. S.; Smith, Z.; Akasofu, S.

2002-05-01

We report on our progress in predicting interplanetary shock arrival time (SAT) in real-time, using three forecast models: the Hakamada-Akasofu-Fry (HAF) modified kinematic model, the Interplanetary Shock Propagation Model (ISPM) and the Shock Time of Arrival (STOA) model. These models are run concurrently to provide real-time predictions of the arrival time at Earth of interplanetary shocks caused by solar events. These "fearless forecasts" are the first, and presently only, publicly distributed predictions of SAT and are undergoing quantitative evaluation for operational utility and scientific benchmarking. All three models predict SAT, but the HAF model also provides a global view of the propagation of interplanetary shocks through the pre-existing, non-uniform heliospheric structure. This allows the forecaster to track the propagation of the shock and to differentiate between shocks caused by solar events and those associated with co-rotating interaction regions (CIRs). This study includes 173 events during the period February, 1997 to October, 2000. Shock predictions were compared with spacecraft observations at the L1 location to determine how well the models perform. Sixty-eight shocks were observed at L1 within 120 hours of an event. We concluded that 6 of these observed shocks were caused by CIRs, and the remainder were caused by solar events. The forecast skill of the models are presented in terms of RMS errors, contingency tables and skill scores commonly used by the weather forecasting community. The false alarm rate for HAF was higher than for ISPM or STOA but much lower than for predictions based upon empirical studies or climatology. Of the parameters used to characterize a shock source at the Sun, the initial speed of the coronal shock, as represented by the observed metric type II speed, has the largest influence on the predicted SAT. We also found that HAF model predictions based upon type II speed are generally better for shocks originating from sites near central meridian, and worse for limb events. This tendency suggests that the observed type II speed is more representative of the interplanetary shock speed for events occurring near central meridian. In particular, the type II speed appears to underestimate the actual Earth-directed IP shock speed when the source of the event is near the limb. Several of the most interesting events (Bastille Day epoch (2000), April Fools Day epoch (2001))will be discussed in more detail with the use of real-time animations.

On numerical instabilities of Godunov-type schemes for strong shocks

NASA Astrophysics Data System (ADS)

Xie, Wenjia; Li, Wei; Li, Hua; Tian, Zhengyu; Pan, Sha

2017-12-01

It is well known that low diffusion Riemann solvers with minimal smearing on contact and shear waves are vulnerable to shock instability problems, including the carbuncle phenomenon. In the present study, we concentrate on exploring where the instability grows out and how the dissipation inherent in Riemann solvers affects the unstable behaviors. With the help of numerical experiments and a linearized analysis method, it has been found that the shock instability is strongly related to the unstable modes of intermediate states inside the shock structure. The consistency of mass flux across the normal shock is needed for a Riemann solver to capture strong shocks stably. The famous carbuncle phenomenon is interpreted as the consequence of the inconsistency of mass flux across the normal shock for a low diffusion Riemann solver. Based on the results of numerical experiments and the linearized analysis, a robust Godunov-type scheme with a simple cure for the shock instability is suggested. With only the dissipation corresponding to shear waves introduced in the vicinity of strong shocks, the instability problem is circumvented. Numerical results of several carefully chosen strong shock wave problems are investigated to demonstrate the robustness of the proposed scheme.

Sepsis and Septic Shock Strategies.

PubMed

Armstrong, Bracken A; Betzold, Richard D; May, Addison K

2017-12-01

Three therapeutic principles most substantially improve organ dysfunction and survival in sepsis: early, appropriate antimicrobial therapy; restoration of adequate cellular perfusion; timely source control. The new definitions of sepsis and septic shock reflect the inadequate sensitivity, specify, and lack of prognostication of systemic inflammatory response syndrome criteria. Sequential (sepsis-related) organ failure assessment more effectively prognosticates in sepsis and critical illness. Inadequate cellular perfusion accelerates injury and reestablishing perfusion limits injury. Multiple organ systems are affected by sepsis and septic shock and an evidence-based multipronged approach to systems-based therapy in critical illness results in improve outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

[An rare complication of scarlet fever : invasive group A streptococcal infection with streptococcal toxic shock syndrome].

PubMed

Warnier, H; Depuis, Z; Nyamugabo, K; Desprechins, B; Seghaye, M-C

2017-03-01

Invasive Group A Streptococcus infections and streptococcal toxic shock syndrome are rare complications of common diseases in children such as scarlet fever or impetigo. These invasive diseases are particulary challenging because of their rapid progression and the lack of predisposing factors in most cases. Prompt diagnosis and treatment are mandatory to reduce the mortality associated with these severe diseases. We report the case of an 8- year-old girl who developped an invasive group A streptococcal disease with osteomyelitis and streptococcal toxic shock syndrome in the course of a classical scarlet fever.

Turbulence Associated With Broadband Shock Noise in Hot Jets

NASA Technical Reports Server (NTRS)

Bridges, James E.; Wernet, Mark P.

2008-01-01

Time-Resolved Particle Image Velocimetry (TRPIV) has been applied to a series of jet flows to measure turbulence statistics associated with broadband shock associated noise (BBSN). Data were acquired in jets of Mach numbers 1.05, 1.185, and 1.4 at different temperatures. Both convergent and ideally expanded nozzles were tested, along with a convergent nozzle modified to minimize screech. Key findings include the effect of heat on shock structure and jet decay, the increase in turbulent velocity when screech is present, and the relative lack of spectral detail associated with the enhanced turbulence.

Depilatory poisoning

MedlinePlus

... the eye) Collapse (shock) Coma (decreased level of consciousness and lack of responsiveness) Diarrhea (watery, bloody) Drooling ... output Rash Slurred speech Stupor (decreased level of consciousness) Vomiting

The ortho:para-H_2 ratio in C- and J-type shocks

NASA Astrophysics Data System (ADS)

Wilgenbus, D.; Cabrit, S.; Pineau des Forêts, G.; Flower, D. R.

2000-04-01

We have computed extensive grids of models of both C- and J-type planar shock waves, propagating in dark, cold molecular clouds, in order to study systematically the behaviour of the ortho:para-H_2 ratio. Careful attention was paid to both macroscopic (dynamical) and microscopic (chemical reactions and collisional population transfer in H_2) aspects. We relate the predictions of the models to observational determinations of the ortho:para-H_2 ratio using both pure rotational lines and rovibrational lines. As an illustration, we consider ISO and ground-based H_2 observations of HH 54. Neither planar C-type nor planar J-type shocks appear able to account fully for these observations. Given the additional constraints provided by the observed ortho:para H_2 ratios, a C-type bowshock, or a C-type precursor followed by a J-type shock, remain as plausible models. Tables~2a-f and 4a-f are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

B-type natriuretic peptide in the recognition of critical congenital heart disease in the newborn infant.

PubMed

Das, Srikant; Chanani, Nikhil K; Deshpande, Shriprasad; Maher, Kevin O

2012-08-01

Infants with congenital heart disease having obstruction to the left ventricular outflow and ductal-dependent systemic circulation can present critically ill with shock. Prompt disease recognition and initiation of prostaglandins are necessary to prevent excess morbidity and mortality. We assessed a large cohort of newborn infants with ductal-dependent systemic circulation to determine if B-type natriuretic peptide (BNP) is consistently elevated at presentation, potentially aiding in diagnosis and treatment. The clinical records of infants with left-sided obstructive lesions admitted from January 2005 to June 2009 were reviewed. Infants were divided into 2 groups: group 1 was diagnosed with cardiogenic/circulatory shock at presentation, and group 2 consisted of infants with ductal-dependent systemic circulation without evidence of shock. B-type natriuretic peptide levels and other variables between the groups were compared. All patients with critical congenital heart disease presenting with shock had elevated BNP levels, ranging from 553 to greater than 5000 pg/mL. Infants in group 1 (shock, n = 36) had significantly higher median BNP levels of 4100 pg/mL at presentation compared with group 2 patients (no shock, n = 86), who had a median BNP of 656 pg/mL (range, 30-3930 pg/mL; P < 0.001). Every 100 U of increase in BNP at presentation increased the likelihood of shock (odds ratio, 100; P < 0.001). B-type natriuretic peptide is markedly elevated in neonates presenting in shock secondary to left-sided obstructive heart disease and is an important diagnostic tool to aid in the rapid identification and treatment of these patients.

Positions of type II fundamental and harmonic sources in the 30-100 MHZ range

NASA Technical Reports Server (NTRS)

Sawant, H. S.; Gergely, T. E.; Kundu, M. R.

1982-01-01

An excellent example of a type III-V burst followed by a type II burst with fundamental and harmonic bands was observed on June 18, 1979 at the Clark Lake Radio Observatory. The observations are described in detail and their implications are discussed with regard to the problem of directionality with respect to the magnetic field lines of the collisionless MHD shock wave generated at the start of the flash phase. It is found that the positions of type III and type II (F) bursts at a number of frequencies are essentially the same, which implies that the shock responsible for the type II radiation follows the path of the type III exciter, that is, the shock propagates along the open field lines.

The solar wind interaction with Mars - Mariner 4, Mars 2, Mars 3, Mars 5, and Phobos 2 observations of bow shock position and shape

NASA Technical Reports Server (NTRS)

Slavin, J. A.; Schwingenschuh, K.; Riedler, W.; Eroshenko, E.

1991-01-01

An aggregate Mars bow shock data set using Mariner 4, Mars 2, Mars 3, Mars 5, and Phobos 2 observations has been analyzed. The results support the earlier conclusion that the mean distance to the subsolar shock at Mars is nearly 1.5 planetary radii, from which gas dynamic models predict an obstacle altitude of 500 km. The Martian bow shock does not appear to vary significantly in shape or altitude with the phase of the solar cycle. The unusually distant dayside bow shock crossings reported by Mars 2 and 3 also appear in the Phobos 3 observations, suggesting that the dayside obstacle can on rare occasions reach altitudes over 1000 km. The Martian bow shock differs from that of Venus in that its mean altitude is greater, it lacks a strong solar cycle variation, and its location is far more variable, including the occurrence of strong bow shocks over the dayside hemisphere at distances at least as great as the orbit of Phobos 2, i.e., 2.8 Mars radii.

Northwest Africa 428: Impact-induced Annealing of an L6 Chondrite Breccia

NASA Technical Reports Server (NTRS)

Rubin, Alan E.

2006-01-01

Northwest Africa (NWA) 428 is an L chondrite that was successively thermally metamorphosed to petrologic type-6, shocked to stage S4-S5, brecciated, and annealed to approximately petrologic type-4. Its thermal and shock history resembles that of the previously studied LL6 chondrite, Miller Range (MIL) 99301, which formed on a different asteroid. The petrologic type-6 classification of NWA 428 is based on its highly recrystallized texture, coarse metal (150 +/- 150 micron), troilite (100 +/- 170 micron), and plagioclase (20-60 micron) grains, and relatively homogeneous olivine (Fa(sub 24.4 +/- 0.6)), low-Ca pyroxene (FS(sub 2.5+/- 0,4) , and plagioclase (Ab(sub 84.2 +/- 0.4) compositions. The petrographic criteria that indicate shock stage S4-S5 include the presence of chromite veinlets, chromite-plagioclase assemblages, numerous occurrences of metallic Cu, irregular troilite grains within metallic Fe-Ni, polycrystalline troilite, duplex plessite, metal and troilite veins, large troilite nodules, and low-Ca clinopyroxene with polysynthetic twins. If the rock had been shocked before thermal metamorphism, low-Ca clinopyroxene produced by the shock event would have transformed into orthopyroxene. Post-shock brecciation is indicated by the presence of recrystallized clasts and highly shocked clasts that form sharp boundaries with the host. Post-shock annealing is indicated by the sharp optical extinction of the olivine grains; during annealing, the damaged olivine crystal lattices healed. If temperatures exceeded those approximating petrologic type-4 (approximately 600-700 C) during annealing, the low-Ca clinopyroxene would have transformed into orthopyroxene. The other shock indicators, likewise, survived the mild annealing. An impact event is the most plausible source of post-metamorphic, post-shock annealing because any A1-26 that may have been present when the asteroid accreted would have decayed away by the time NWA 428 was annealed. The similar inferred histories of NWA 428 (L6) and MIL 99301 (LL6) indicate that impact heating affected more than 1 ordinary chondrite parent body.

Spherical shock waves in general relativity

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

Nutku, Y.

1991-11-15

We present the metric appropriate to a spherical shock wave in the framework of general relativity. This is a Petrov type-{ital N} vacuum solution of the Einstein field equations where the metric is continuous across the shock and the Riemann tensor suffers a step-function discontinuity. Spherical gravitational waves are described by type-{ital N} Robinson-Trautman metrics. However, for shock waves the Robinson-Trautman solutions are unacceptable because the metric becomes discontinuous in the Robinson-Trautman coordinate system. Other coordinate systems that have so far been introduced for describing Robinson-Trautman solutions also suffer from the same defect. We shall present the {ital C}{sup 0}-formmore » of the metric appropriate to spherical shock waves using Penrose's approach of identification with warp. Further extensions of Penrose's method yield accelerating, as well as coupled electromagnetic-gravitational shock-wave solutions.« less

Toll-like receptor 2-independent host innate immune response against an epidemic strain of Streptococcus suis that causes a toxic shock-like syndrome in humans.

PubMed

Lachance, Claude; Segura, Mariela; Gerber, Pehuén Pereyra; Xu, Jianguo; Gottschalk, Marcelo

2013-01-01

Streptococcus suis is an emerging zoonotic agent causing meningitis and septicemia. Outbreaks in humans in China with atypical cases of streptococcal toxic shock-like syndrome have been described to be caused by a clonal epidemic S. suis strain characterized as sequence type (ST) 7 by multilocus sequence typing, different from the classical ST1 usually isolated in Europe. Previous in vitro studies showed that Toll-like receptor (TLR) 2 plays a major role in S. suis ST1 interactions with host cells. In the present study, the in vivo role of TLR2 in systemic infections caused by S. suis ST1 or ST7 strains using TLR2 deficient (TLR2(-/-)) mice was evaluated. TLR2-mediated recognition significantly contributes to the acute disease caused by the highly virulent S. suis ST1 strain, since the TLR2(-/-) mice remained unaffected when compared to wild type (WT) mice. The lack of mortality could not be associated with a lower bacterial burden; however, a significant decrease in the induction of pro-inflammatory mediators, as evaluated by microarray, real-time PCR and protein assays, was observed. On the other hand, TLR2(-/-) mice infected with the epidemic ST7 strain presented no significant differences regarding survival and expression of pro-inflammatory mediators when compared to the WT mice. Together, these results show a TLR2-independent host innate immune response to S. suis that depends on the strain.

Solar Type II Radio Bursts and IP Type II Events

NASA Technical Reports Server (NTRS)

Cane, H. V.; Erickson, W. C.

2005-01-01

We have examined radio data from the WAVES experiment on the Wind spacecraft in conjunction with ground-based data in order to investigate the relationship between the shocks responsible for metric type II radio bursts and the shocks in front of coronal mass ejections (CMEs). The bow shocks of fast, large CMEs are strong interplanetary (IP) shocks, and the associated radio emissions often consist of single broad bands starting below approx. 4 MHz; such emissions were previously called IP type II events. In contrast, metric type II bursts are usually narrowbanded and display two harmonically related bands. In addition to displaying complete dynamic spectra for a number of events, we also analyze the 135 WAVES 1 - 14 MHz slow-drift time periods in 2001-2003. We find that most of the periods contain multiple phenomena, which we divide into three groups: metric type II extensions, IP type II events, and blobs and bands. About half of the WAVES listings include probable extensions of metric type II radio bursts, but in more than half of these events, there were also other slow-drift features. In the 3 yr study period, there were 31 IP type II events; these were associated with the very fastest CMEs. The most common form of activity in the WAVES events, blobs and bands in the frequency range between 1 and 8 MHz, fall below an envelope consistent with the early signatures of an IP type II event. However, most of this activity lasts only a few tens of minutes, whereas IP type II events last for many hours. In this study we find many examples in the radio data of two shock-like phenomena with different characteristics that occur simultaneously in the metric and decametric/hectometric bands, and no clear example of a metric type II burst that extends continuously down in frequency to become an IP type II event. The simplest interpretation is that metric type II bursts, unlike IP type II events, are not caused by shocks driven in front of CMEs.

RR-MR transition of a Type V shock interaction in inviscid double-wedge flow with high-temperature gas effects

NASA Astrophysics Data System (ADS)

Xiong, W.; Li, J.; Zhu, Y.; Luo, X.

2018-07-01

The transition between regular reflection (RR) and Mach reflection (MR) of a Type V shock-shock interaction on a double-wedge geometry with non-equilibrium high-temperature gas effects is investigated theoretically and numerically. A modified shock polar method that involves thermochemical non-equilibrium processes is applied to calculate the theoretical critical angles of transition based on the detachment criterion and the von Neumann criterion. Two-dimensional inviscid numerical simulations are performed correspondingly to reveal the interactive wave patterns, the transition processes, and the critical transition angles. The theoretical and numerical results of the critical transition angles are compared, which shows evident disagreement, indicating that the transition mechanism between RR and MR of a Type V shock interaction is beyond the admissible scope of the classical theory. Numerical results show that the collisions of triple points of the Type V interaction cause the transition instead. Compared with the frozen counterpart, it is found that the high-temperature gas effects lead to a larger critical transition angle and a larger hysteresis interval.

Advanced Computational Modeling Approaches for Shock Response Prediction

NASA Technical Reports Server (NTRS)

Derkevorkian, Armen; Kolaini, Ali R.; Peterson, Lee

2015-01-01

Motivation: (1) The activation of pyroshock devices such as explosives, separation nuts, pin-pullers, etc. produces high frequency transient structural response, typically from few tens of Hz to several hundreds of kHz. (2) Lack of reliable analytical tools makes the prediction of appropriate design and qualification test levels a challenge. (3) In the past few decades, several attempts have been made to develop methodologies that predict the structural responses to shock environments. (4) Currently, there is no validated approach that is viable to predict shock environments overt the full frequency range (i.e., 100 Hz to 10 kHz). Scope: (1) Model, analyze, and interpret space structural systems with complex interfaces and discontinuities, subjected to shock loads. (2) Assess the viability of a suite of numerical tools to simulate transient, non-linear solid mechanics and structural dynamics problems, such as shock wave propagation.

Tactical Damage Control Resuscitation.

PubMed

Fisher, Andrew D; Miles, Ethan A; Cap, Andrew P; Strandenes, Geir; Kane, Shawn F

2015-08-01

Recently the Committee on Tactical Combat Casualty Care changed the guidelines on fluid use in hemorrhagic shock. The current strategy for treating hemorrhagic shock is based on early use of components: Packed Red Blood Cells (PRBCs), Fresh Frozen Plasma (FFP) and platelets in a 1:1:1 ratio. We suggest that lack of components to mimic whole blood functionality favors the use of Fresh Whole Blood in managing hemorrhagic shock on the battlefield. We present a safe and practical approach for its use at the point of injury in the combat environment called Tactical Damage Control Resuscitation. We describe pre-deployment preparation, assessment of hemorrhagic shock, and collection and transfusion of fresh whole blood at the point of injury. By approaching shock with goal-directed therapy, it is possible to extend the period of survivability in combat casualties. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.

Shock wave and flame front induced detonation in a rapid compression machine

NASA Astrophysics Data System (ADS)

Wang, Y.; Qi, Y.; Xiang, S.; Mével, R.; Wang, Z.

2018-05-01

The present study focuses on one mode of detonation initiation observed in a rapid compression machine (RCM). This mode is referred to as shock wave and flame front-induced detonation (SWFID). Experimental high-speed imaging and two-dimensional numerical simulations with skeletal chemistry are combined to unravel the dominant steps of detonation initiation under SWFID conditions. It is shown that the interaction between the shock wave generated by the end-gas auto-ignition and the spherical flame creates a region of high pressure and temperature which enables the acceleration of the flame front and the detonation onset. The experimental observation lacks adequate spatial and temporal resolution despite good reproducibility of the detonation onset. Based on the numerical results, phenomenological interpretation of the event within the framework of shock wave refraction indicates that the formation of a free-precursor shock wave at the transition between regular and irregular refraction may be responsible for detonation onset. The present results along with previous findings on shock wave reflection-induced detonation in the RCM indicate that super-knock occurs after the interaction of the shock wave generated by end-gas auto-ignition with the RCM walls, preignition flame, or another shock wave.

The Wardle Instability in Interstellar Shocks. 2; Gas Temperture and Line Emission

NASA Technical Reports Server (NTRS)

Neufeld, David A.; Stone, James M.

1997-01-01

We have modeled the gas temperature structure in unstable C-type shocks and obtained predictions for the resultant CO and H2 rotational line emissions, using numerical simulations of the Wardle instability. Our model for the thermal balance of the gas includes ion-neutral frictional heating; compressional heating; radiative cooling due to rotational and ro-vibrational transitions of the molecules CO, H2O, and H2; and gas-grain collisional cooling. We obtained results for the gas temperature distribution in-and H2 and CO line emission from-shocks of neutral Alfvenic Mach number 10 and velocity 20 or 40 km/ s in which the Wardle instability has saturated. Both two- and three-dimensional simulations were carried out for shocks in which the preshock magnetic field is perpendicular to the shock propagation direction, and a two-dimensional simulation was carried out for the case in which the magnetic field is obliquely oriented with respect to the shock propagation direction. Although the Wardle instability profoundly affects the density structure behind C-type shocks, most of the shock-excited molecular line emission is generated upstream of the region where the strongest effects of the instability are felt. Thus the Wardle instability has a relatively small effect on the overall gas temperature distribution in-and the emission-line spectrum from-C-type shocks, at least for the cases that we have considered. In none of the cases that we have considered thus far did any of the predicted emission-line luminosities change by more than a factor of 2.5, and in most cases the effects of instability were significantly smaller than that. Slightly larger changes in the line luminosities seem likely for three-dimensional simulations of oblique shocks, although such simulations have yet to be carried out and lie beyond the scope of this study. Given the typical uncertainties that are always present when model predictions are compared with real astronomical data, we conclude that Wardle instability does not imprint any clear observational signature on the shock-excited CO and H2 line strengths. This result justifies the use of one-dimensional steady shock models in the interpretation of observations of shock-excited line emission in regions of star formation. Our three-dimensional simulations of perpendicular shocks revealed the presence of warm filamentary structures that are aligned along the magnetic field, a result that is of possible relevance to models of water maser emission from C-type shocks.

Revisiting first type self-similar solutions of explosions containing ultrarelativistic shocks

NASA Astrophysics Data System (ADS)

Tian, Jun

2018-05-01

We revisit the first type self-similar solutions for ultrarelativistic shock waves produced by explosions propagating into cold external medium whose density profile decreases with radius as ρ ∝ r-k. The first-type solutions proposed by Blandford and McKee (hereafter BM solution) conforms to the global conservation of energy and applies when k < 4. They have been found to be invalid when k > 17/4 because of the divergence of total energy contained in the shocked fluids. So far no attention has been paid to the particle number. We use the BM solution to calculate the total particle number traversed by the shock and find that it diverges when k > 3. This is inconsistent with the finite particles in the surrounding medium. We propose a possible solution when k > 3 based on the conservation of particle number and discuss its implication for the second-type solutions.

Shock absorber operates over wide range

NASA Technical Reports Server (NTRS)

Creasy, W. K.; Jones, J. C.

1965-01-01

Piston-type hydraulic shock absorber, with a metered damping system, operates over a wide range of kinetic energy loading rates. It is used for absorbing shock and vibration on mounted machinery and heavy earth-moving equipment.

Laminar and turbulent flow computations of Type 4 shock-shock interference aerothermal loads using unstructured grids

NASA Technical Reports Server (NTRS)

Vemaganti, Gururaja R.

1994-01-01

This report presents computations for the Type 4 shock-shock interference flow under laminar and turbulent conditions using unstructured grids. Mesh adaptation was accomplished by remeshing, refinement, and mesh movement. Two two-equation turbulence models were used to analyze turbulent flows. The mean flow governing equations and the turbulence governing equations are solved in a coupled manner. The solution algorithm and the details pertaining to its implementation on unstructured grids are described. Computations were performed at two different freestream Reynolds numbers at a freestream Mach number of 11. Effects of the variation in the impinging shock location are studied. The comparison of the results in terms of wall heat flux and wall pressure distributions is presented.

Success and failure of the defibrillation shock: insights from a simulation study.

PubMed

Skouibine, K; Trayanova, N; Moore, P

2000-07-01

This simulation study presents a further inquiry into the mechanisms by which a strong electric shock fails to halt life-threatening cardiac arrhythmias. The research uses a model of the defibrillation process that represents a sheet of myocardium as a bidomain. The tissue consists of nonuniformly curved fibers in which spiral wave reentry is initiated. Monophasic defibrillation shocks are delivered via two line electrodes that occupy opposite tissue boundaries. In some simulation experiments, the polarity of the shock is reversed. Electrical activity in the sheet is compared for failed and successful shocks under controlled conditions. The maps of transmembrane potential and activation times calculated during and after the shock demonstrate that weak shocks fail to terminate the reentrant activity via two major mechanisms. As compared with strong shocks, weak shocks result in (1) smaller extension of refractoriness in the areas depolarized by the shock, and (2) slower or incomplete activation of the excitable gap created by deexcitation of the negatively polarized areas. In its turn, mechanism 2 is associated with one or more of the following events: (a) lack of some break excitations, (b) latency in the occurrence of the break excitations, and (c) slower propagation through deexcited areas. Reversal of shock polarity results in a change of the extent of the regions of deexcitation, and thus, in a change in defibrillation threshold. The results of this study indicate the paramount importance of shock-induced deexcitation in both defibrillation and postshock arrhythmogenesis.

Low Intensity Extracorporeal Shock Wave Therapy Improves Erectile Function in a Model of Type II Diabetes Independently of NO/cGMP Pathway.

PubMed

Assaly-Kaddoum, Rana; Giuliano, François; Laurin, Miguel; Gorny, Diane; Kergoat, Micheline; Bernabé, Jacques; Vardi, Yoram; Alexandre, Laurent; Behr-Roussel, Delphine

2016-09-01

Erectile dysfunction is highly prevalent in type II diabetes mellitus. Low intensity extracorporeal shock wave therapy improves erectile function in patients with erectile dysfunction of vasculogenic origin, including diabetes. However, its mode of action remains unknown. We investigated the effects of low intensity extracorporeal shock wave therapy compared to or combined with sildenafil on erectile dysfunction in a type II diabetes mellitus model. Our purpose was to test our hypothesis of a mode of action targeting the cavernous nitric oxide/cyclic guanosine monophosphate pathway. GK rats, a validated model of type II diabetes mellitus, and age matched Wistar rats were treated with low intensity extracorporeal shock wave therapy twice weekly for 3 weeks. Treatment was repeated after a 3-week no-treatment interval. The penis was stretched and dipped in a specifically designed water-filled cage. Shock waves were delivered by a calibrated probe yielding a controlled energy flux density (0.09 mJ/mm(2)). The probe was attached to an electrohydraulic unit with a focused shock wave source, allowing for accurate extrapolation to humans. Following a 4-week washout period erectile function was assessed as well as endothelium dependent and independent, and nitrergic relaxations of the corpus cavernosum of GK rats. Low intensity extracorporeal shock wave therapy significantly improved erectile function in GK rats to the same extent as sildenafil. Treatment effects were potentiated when combined with sildenafil. Shock wave effects were not associated with improved cavernous endothelium dependent or independent, or nitrergic reactivity. Low intensity extracorporeal shock wave therapy improved erectile function in GK rats. Unexpectedly, this was not mediated by a nitric oxide/cyclic guanosine monophosphate dependent mechanism. Sildenafil increased shock wave efficacy. This preclinical paradigm to deliver low intensity extracorporeal shock wave therapy to the rat penis should help further exploration of the mode of action of this therapy on erectile tissue. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Integrating Turnover Reasons and Shocks with Turnover Decision Processes

ERIC Educational Resources Information Center

Maertz, Carl P., Jr.; Kmitta, Kayla R.

2012-01-01

We interviewed and classified 186 quitters from many jobs and organizations via a theoretically-based protocol into five decision process types. We then tested exploratory hypotheses comparing users of these types on their propensity to report certain turnover reasons and turnover shocks. "Impulsive-type quitters," with neither a job offer in hand…

Different Types of Ion Populations Upstream of the 2013 October 8 Interplanetary Shock

NASA Astrophysics Data System (ADS)

Kajdič, Primož; Hietala, Heli; Blanco-Cano, Xóchitl

2017-11-01

We show for the first time that different types of suprathermal ion distributions may exist upstream of a single interplanetary shock. ACE and the two ARTEMIS satellites observed a shock on 2013 October 8. The ARTEMIS P1 and P2 spacecraft first observed field-aligned ions (P1) and gyrating ions (P2) arriving from the shock. These were followed by intermediate ions and later by a diffuse population. At the location of the P2 the shock exhibited an Alfvénic Mach number of M A = 5.7 and was marginally quasi-perpendicular ({θ }{Bn}=47^\\circ ). At P1 spacecraft the shock was weaker (M A = 4.9) and more perpendicular ({θ }{Bn}=61^\\circ ). Consequently, the observed suprathermal ion and ultra-low-frequency wave properties were somewhat different. At P2 the ultra-low-frequency waves are more intense and extend farther upstream from the shock. The energies of field-aligned and gyrating ions in the shock rest-frame were ˜20 keV, which is much more than in the case of the stronger (M A = 6-7) Earth’s bow shock, where they are less than 10 keV.

Small interfering RNA mediated Poly (ADP-ribose) Polymerase-1 inhibition upregulates the heat shock response in a murine fibroblast cell line

PubMed Central

2011-01-01

Poly (ADP-ribose) polymerase-1 (PARP-1) is a highly conserved multifunctional enzyme, and its catalytic activity is stimulated by DNA breaks. The activation of PARP-1 and subsequent depletion of nicotinamide adenine dinucleotide (NAD+) and adenosine triphosphate (ATP) contributes to significant cytotoxicity in inflammation of various etiologies. On the contrary, induction of heat shock response and production of heat shock protein 70 (HSP-70) is a cytoprotective defense mechanism in inflammation. Recent data suggests that PARP-1 modulates the expression of a number of cellular proteins at the transcriptional level. In this study, small interfering RNA (siRNA) mediated PARP-1 knockdown in murine wild-type fibroblasts augmented heat shock response as compared to untreated cells (as evaluated by quantitative analysis of HSP-70 mRNA and HSP-70 protein expression). These events were associated with increased DNA binding of the heat shock factor-1 (HSF-1), the major transcription factor of the heat shock response. Co-immunoprecipitation experiments in nuclear extracts of the wild type cells demonstrated that PARP-1directly interacted with HSF-1. These data demonstrate that, in wild type fibroblasts, PARP-1 plays a pivotal role in modulating the heat shock response both through direct interaction with HSF-1 and poly (ADP-ribosylation). PMID:21345219

Immunological Development and Cardiovascular Function Are Normal in Annexin VI Null Mutant Mice

PubMed Central

Hawkins, Tim E.; Roes, Jürgen; Rees, Daryl; Monkhouse, Jayne; Moss, Stephen E.

1999-01-01

Annexins are calcium-binding proteins of unknown function but which are implicated in important cellular processes, including anticoagulation, ion flux regulation, calcium homeostasis, and endocytosis. To gain insight into the function of annexin VI, we performed targeted disruption of its gene in mice. Matings between heterozygous mice produced offspring with a normal Mendelian pattern of inheritance, indicating that the loss of annexin VI did not interfere with viability in utero. Mice lacking annexin VI reached sexual maturity at the same age as their normal littermates, and both males and females were fertile. Because of interest in the role of annexin VI in cardiovascular function, we examined heart rate and blood pressure in knockout and wild-type mice and found these to be identical in the two groups. Similarly, the cardiovascular responses of both sets of mice to septic shock were indistinguishable. We also examined components of the immune system and found no differences in thymic, splenic, or bone marrow lymphocyte levels between knockout and wild-type mice. This is the first study of annexin knockout mice, and the lack of a clear phenotype has broad implications for current views of annexin function. PMID:10567528

Novel toxic shock syndrome toxin-1 amino acids required for biological activity.

PubMed

Brosnahan, Amanda J; Schaefers, Matthew M; Amundson, William H; Mantz, Mary J; Squier, Christopher A; Peterson, Marnie L; Schlievert, Patrick M

2008-12-09

Superantigens interact with T lymphocytes and macrophages to cause T lymphocyte proliferation and overwhelming cytokine production, which lead to toxic shock syndrome. Staphylococcus aureus superantigen toxic shock syndrome toxin-1 is a major cause of menstrual toxic shock syndrome. In general, superantigen-secreting S. aureus remains localized at the vaginal surface, and the superantigen must therefore penetrate the vaginal mucosa to interact with underlying immune cells to cause toxic shock syndrome. A dodecapeptide region (toxic shock syndrome toxin-1 amino acids F119-D130), relatively conserved among superantigens, has been implicated in superantigen penetration of the epithelium. The purpose of this study was to determine amino acids within this dodecapeptide region that are required for interaction with vaginal epithelium. Alanine mutations were constructed in S. aureus toxic shock syndrome toxin-1 amino acids D120 to D130. All mutants maintained superantigenicity, and selected mutants were lethal when given intravenously to rabbits. Toxic shock syndrome toxin-1 induces interleukin-8 from immortalized human vaginal epithelial cells; however, three toxin mutants (S127A, T128A, and D130A) induced low levels of interleukin-8 compared to wild type toxin. When carboxy-terminal mutants (S127A to D130A) were administered vaginally to rabbits, D130A was nonlethal, while S127A and T128A demonstrated delayed lethality compared to wild type toxin. In a porcine ex vivo permeability model, mutant D130A penetrated the vaginal mucosa more quickly than wild type toxin. Toxic shock syndrome toxin-1 residue D130 may contribute to binding an epithelial receptor, which allows it to penetrate the vaginal mucosa, induce interleukin-8, and cause toxic shock syndrome.

Automated Detection and Analysis of Interplanetary Shocks Running Real-Time on the Web

NASA Astrophysics Data System (ADS)

Vorotnikov, V.; Smith, C. W.; Hu, Q.; Szabo, A.; Skoug, R. M.; Cohen, C. M.; Davis, A. J.

2008-05-01

The ACE real-time data stream provides web-based now-casting capabilities for solar wind conditions upstream of Earth. We have built a fully automated code that finds and analyzes interplanetary shocks as they occur and posts their solutions on the Web for possible real-time application to space weather nowcasting. Shock analysis algorithms based on the Rankine-Hugoniot jump conditions exist and are in wide-spread use today for the interactive analysis of interplanetary shocks yielding parameters such as shock speed and propagation direction and shock strength in the form of compression ratios. At a previous meeting we reported on efforts to develop a fully automated code that used ACE Level-2 (science quality) data to prove the applicability and correctness of the code and the associated shock-finder. We have since adapted the code to run ACE RTSW data provided by NOAA. This data lacks the full 3-dimensional velocity vector for the solar wind and contains only a single component wind speed. We show that by assuming the wind velocity to be radial strong shock solutions remain essentially unchanged and the analysis performs as well as it would if 3-D velocity components were available. This is due, at least in part, to the fact that strong shocks tend to have nearly radial shock normals and it is the strong shocks that are most effective in space weather applications. Strong shocks are the only shocks that concern us in this application. The code is now running on the Web and the results are available to all.

75 FR 41078 - Revisions to the Commerce Control List To Update and Clarify Crime Control License Requirements

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-15

... * * * * * 0A985 Discharge type arms and devices to administer electric shock, for example, stun guns, shock batons, shock shields, electric cattle prods, immobilization guns and projectiles; except equipment used...

Importance of CME Radial Expansion on the Ability of Slow CMEs to Drive Shocks

NASA Astrophysics Data System (ADS)

Lugaz, N.; Farrugia, C. J.; Winslow, R. M.; Small, C. R.; Manion, T.; Savani, N.

2017-12-01

Coronal mass ejections (CMEs) may disturb the solar wind either by overtaking it, or by expanding into it, or both. CMEs whose front moves faster in the solar wind frame than the fast magnetosonic speed, drive shocks. In general, near 1 AU, CMEs with speed greater than about 500 km s-1 drive shocks, whereas slower CMEs do not. However, CMEs as slow as 350 km s-1 may sometimes, although rarely, drive shocks. Here, we study these slow CMEs with shocks and investigate the importance of CME expansion in contributing to their ability to drive shocks and in enhancing shock strength. Our focus is on CMEs with average speeds under 375 km s-1. From Wind measurements from 1996 to 2016, we find 22 cases of such shock-driving slow CMEs, and, for about half of them, the existence of the shock appears to be strongly related to CME expansion. We also investigate the proportion of all CMEs with speeds under 500 km s-1 with and without shocks in solar cycles 23 and 24, depending on their speed. We find no systematic difference, as might have been expected on the basis of the lower solar wind and Alfven speeds reported for solar cycle 24 vs. 23. The slower expansion speed of CMEs in solar cycle 24 is a reasonable explanation for this lack of increased frequency of shocks, but further studies are required.

Development of Partial Discharging Simulation Test Equipment

NASA Astrophysics Data System (ADS)

Kai, Xue; Genghua, Liu; Yan, Jia; Ziqi, Chai; Jian, Lu

2017-12-01

In the case of partial discharge training for recruits who lack of on-site work experience, the risk of physical shock and damage of the test equipment may be due to the limited skill level and improper operation by new recruits. Partial discharge simulation tester is the use of simulation technology to achieve partial discharge test process simulation, relatively true reproduction of the local discharge process and results, so that the operator in the classroom will be able to get familiar with and understand the use of the test process and equipment.The teacher sets up the instrument to display different partial discharge waveforms so that the trainees can analyze the test results of different partial discharge types.

Selection and Characterization of Dunaliella salina Mutants Defective in Haloadaptation 1

PubMed Central

Chitlaru, Edith; Pick, Uri

1989-01-01

A technique for selection of Dunaliella mutants defective in their capacity to recover from osmotic shocks has been developed. The selection is based on physical separation of mutants on density gradients. This technique takes advantage of the fact that Dunaliella cells, when exposed to osmotic shocks, initially change volume and density due to water gain or loss and subsequently recover their volume and density by readjusting their intracellular glycerol. Eight mutants that do not recover their original density following hyperosmotic shocks have been isolated. The mutants grow similar to wild type cells in 1 molar NaCl, and recover like the wild type from hypotonic shocks but are defective in recovering from hypertonic shocks. A partial characterization of one of the mutants is described. Images Figure 1 PMID:16667101

The differential effects of heat-shocking on the viability of spores from Bacillus anthracis, Bacillus subtilis, and Clostridium sporogenes after treatment with peracetic acid- and glutaraldehyde-based disinfectants

PubMed Central

March, Jordon K; Pratt, Michael D; Lowe, Chinn-Woan; Cohen, Marissa N; Satterfield, Benjamin A; Schaalje, Bruce; O'Neill, Kim L; Robison, Richard A

2015-01-01

This study investigated (1) the susceptibility of Bacillus anthracis (Ames strain), Bacillus subtilis (ATCC 19659), and Clostridium sporogenes (ATCC 3584) spores to commercially available peracetic acid (PAA)- and glutaraldehyde (GA)-based disinfectants, (2) the effects that heat-shocking spores after treatment with these disinfectants has on spore recovery, and (3) the timing of heat-shocking after disinfectant treatment that promotes the optimal recovery of spores deposited on carriers. Suspension tests were used to obtain inactivation kinetics for the disinfectants against three spore types. The effects of heat-shocking spores after disinfectant treatment were also determined. Generalized linear mixed models were used to estimate 6-log reduction times for each spore type, disinfectant, and heat treatment combination. Reduction times were compared statistically using the delta method. Carrier tests were performed according to AOAC Official Method 966.04 and a modified version that employed immediate heat-shocking after disinfectant treatment. Carrier test results were analyzed using Fisher's exact test. PAA-based disinfectants had significantly shorter 6-log reduction times than the GA-based disinfectant. Heat-shocking B. anthracis spores after PAA treatment resulted in significantly shorter 6-log reduction times. Conversely, heat-shocking B. subtilis spores after PAA treatment resulted in significantly longer 6-log reduction times. Significant interactions were also observed between spore type, disinfectant, and heat treatment combinations. Immediately heat-shocking spore carriers after disinfectant treatment produced greater spore recovery. Sporicidal activities of disinfectants were not consistent across spore species. The effects of heat-shocking spores after disinfectant treatment were dependent on both disinfectant and spore species. Caution must be used when extrapolating sporicidal data of disinfectants from one spore species to another. Heat-shocking provides a more accurate picture of spore survival for only some disinfectant/spore combinations. Collaborative studies should be conducted to further examine a revision of AOAC Official Method 966.04 relative to heat-shocking. PMID:26185111

Demonstration of a Novel Method for Measuring Mass-loss Rates for Massive Stars

NASA Astrophysics Data System (ADS)

Kobulnicky, Henry A.; Chick, William T.; Povich, Matthew S.

2018-03-01

The rate at which massive stars eject mass in stellar winds significantly influences their evolutionary path. Cosmic rates of nucleosynthesis, explosive stellar phenomena, and compact object genesis depend on this poorly known facet of stellar evolution. We employ an unexploited observational technique for measuring the mass-loss rates of O and early-B stars. Our approach, which has no adjustable parameters, uses the principle of pressure equilibrium between the stellar wind and the ambient interstellar medium for a high-velocity star generating an infrared bow shock nebula. Results for 20 bow-shock-generating stars show good agreement with two sets of theoretical predictions for O5–O9.5 main-sequence stars, yielding \\dot{M} = 1.3 × 10‑6 to 2 × 10‑9 {M}ȯ {yr}}-1. Although \\dot{M} values derived for this sample are smaller than theoretical expectations by a factor of about two, this discrepancy is greatly reduced compared to canonical mass-loss methods. Bow-shock-derived mass-loss rates are factors of 10 smaller than Hα-based measurements (uncorrected for clumping) for similar stellar types and are nearly an order of magnitude larger than P4+ and some other diagnostics based on UV absorption lines. Ambient interstellar densities of at least several cm‑3 appear to be required for formation of a prominent infrared bow shock nebula. Measurements of \\dot{M} for early-B stars are not yet compelling owing to the small number in our sample and the lack of clear theoretical predictions in the regime of lower stellar luminosities. These results may constitute a partial resolution of the extant “weak-wind problem” for late-O stars. The technique shows promise for determining mass-loss rates in the weak-wind regime.

Myeloid-derived NF-κB negative regulation of PU.1 and cEBPβ-driven pro-inflammatory cytokine production restrains LPS-induced Shock

PubMed Central

Vanoni, Simone; Tsai, Yi Ting; Waddell, Amanda; Waggoner, Lisa; Klarquist, Jared; Divanovic, Senad; Hoebe, Kasper; Steinbrecher, Kris A.; Hogan, Simon P.

2017-01-01

Sepsis is a life-threatening event predominantly caused by gram-negative bacteria. Bacterial infection causes a pronounced macrophage (MΦ) and dendritic cell (DC) activation that leads to excessive pro-inflammatory cytokine interleukin (IL)-1β, IL-6, and Tumor necrosis factor (TNF)-α production (cytokine storm), resulting in endotoxic shock. Previous experimental studies have revealed that inhibiting Nuclear Factor kappa Beta (NF-κB) signaling ameliorates disease symptoms; however, the contribution of myeloid p65 in endotoxic shock remains elusive. In this study, we demonstrate increased mortality in mice lacking p65 in the myeloid lineage (p65Δmye) compared to wild type (WT) mice upon ultra-pure LPS (U-LPS) challenge. We show that increased susceptibility to Lipopolysaccharide (LPS)-induced shock was associated with elevated serum level of IL-1β and IL-6. Mechanistic analyses revealed that LPS-induced pro-inflammatory cytokine production was ameliorated in p65-deficient bone marrow–derived macrophages (BMDMs); however, p65-deficient “activated” peritoneal macrophages (MΦs) exhibited elevated IL-1β and IL-6. We show that the elevated pro-inflammatory cytokine secretion was due in part to increased accumulation of IL-1β mRNA and protein in activated inflammatory MΦs. The increased IL-1β was linked with heightened binding of PU.1 and CCAAT/Enhancer Binding Protein Beta (cEBPβ to Il1b and Il6 promoters in activated inflammatory MΦs. Our data provides insight into a role for NF-κB in the negative regulation of pro-inflammatory cytokines in myeloid cells. PMID:27932520

Hierarchical functional specificity of cytosolic heat shock protein 70 (Hsp70) nucleotide exchange factors in yeast.

PubMed

Abrams, Jennifer L; Verghese, Jacob; Gibney, Patrick A; Morano, Kevin A

2014-05-09

Heat shock protein 70 (Hsp70) molecular chaperones play critical roles in protein homeostasis. In the budding yeast Saccharomyces cerevisiae, cytosolic Hsp70 interacts with up to three types of nucleotide exchange factors (NEFs) homologous to human counterparts: Sse1/Sse2 (Heat shock protein 110 (Hsp110)), Fes1 (HspBP1), and Snl1 (Bag-1). All three NEFs stimulate ADP release; however, it is unclear why multiple distinct families have been maintained throughout eukaryotic evolution. In this study we investigate NEF roles in Hsp70 cell biology using an isogenic combinatorial collection of NEF deletion mutants. Utilizing well characterized model substrates, we find that Sse1 participates in most Hsp70-mediated processes and is of particular importance in protein biogenesis and degradation, whereas Fes1 contributes to a minimal extent. Surprisingly, disaggregation and resolubilization of thermally denatured firefly luciferase occurred independently of NEF activity. Simultaneous deletion of SSE1 and FES1 resulted in constitutive activation of heat shock protein expression mediated by the transcription factor Hsf1, suggesting that these two factors are important for modulating stress response. Fes1 was found to interact in vivo preferentially with the Ssa family of cytosolic Hsp70 and not the co-translational Ssb homolog, consistent with the lack of cold sensitivity and protein biogenesis phenotypes for fes1Δ cells. No significant consequence could be attributed to deletion of the minor Hsp110 SSE2 or the Bag homolog SNL1. Together, these lines of investigation provide a comparative analysis of NEF function in yeast that implies Hsp110 is the principal NEF for cytosolic Hsp70, making it an ideal candidate for therapeutic intervention in human protein folding disorders.

Survival of microbial life under shock compression: implications for Panspermia

NASA Astrophysics Data System (ADS)

Burchell, M.

2007-09-01

An analysis is carried out of the survival fraction of micro-organisms exposed to extreme shock pressures. A variety of data sources are used in this analysis. The key findings are that survival depends on the behaviour of the cell wall. Below a critical shock pressure there is a relatively slow fall in survival fraction as shock pressures increase. Above the critical threshold survival starts to fall rapidly as shock pressure increases further. The critical shock pressures found here are in the range 2.4 to 20 GPa, and vary not only from organism to organism, but also depend on the growth stage of given organisms, with starved (i.e., no growth) states favoured for survival. At the shock pressures typical of those involved in interplanetary transfer of rocky materials, the survival fractions are found to be small but finite. This lends credence to the idea of Panspermia, i.e. life may naturally migrate through space. Thus for example, Martian meteorites should not a prior be considered as sterile due to the shock processes they have undergone, but their lack of viable micro-organisms either reflects no such life being present at the source at the time of departure or the influence of other hazardous processes such as radiation in space or heating of surfaces during entry into a planetary atmosphere.

Formation of Radio Type II Bursts During a Multiple Coronal Mass Ejection Event

NASA Astrophysics Data System (ADS)

Al-Hamadani, Firas; Pohjolainen, Silja; Valtonen, Eino

2017-12-01

We study the solar event on 27 September 2001 that consisted of three consecutive coronal mass ejections (CMEs) originating from the same active region, which were associated with several periods of radio type II burst emission at decameter-hectometer (DH) wavelengths. Our analysis shows that the first radio burst originated from a low-density environment, formed in the wake of the first, slow CME. The frequency-drift of the burst suggests a low-speed burst driver, or that the shock was not propagating along the large density gradient. There is also evidence of band-splitting within this emission lane. The origin of the first shock remains unclear, as several alternative scenarios exist. The second shock showed separate periods of enhanced radio emission. This shock could have originated from a CME bow shock, caused by the fast and accelerating second or third CME. However, a shock at CME flanks is also possible, as the density depletion caused by the three CMEs would have affected the emission frequencies and hence the radio source heights could have been lower than usual. The last type II burst period showed enhanced emission in a wider bandwidth, which was most probably due to the CME-CME interaction. Only one shock that could reliably be associated with the investigated CMEs was observed to arrive near Earth.

Characteristics of shocks in the solar corona, as inferred from radio, optical, and theoretical investigations

NASA Technical Reports Server (NTRS)

Maxwell, A.; Dryer, M.

1982-01-01

Solar radio bursts of spectral type II provide one of the chief diagnostics for the propagation of shocks through the solar corona. Radio data on the shocks are compared with computer models for propagation of fast-mode MHD shocks through the solar corona. Data on coronal shocks and high-velocity ejecta from solar flares are then discussed in terms of a general model consisting of three main velocity regimes.

Petrology of unshocked crystalline rocks and shock effects in lunar rocks and minerals

USGS Publications Warehouse

Chao, E.C.T.; James, O.B.; Minkin, J.A.; Boreman, J.A.; Jackson, E.D.; Raleigh, C.B.

1970-01-01

On the basis of rock modes, textures, and mineralogy, unshocked crystalline rocks are classified into a dominant ilmenite-rich suite (subdivided into intersertal, ophitic, and hornfels types) and a subordinate feldspar-rich suite (subdivided into poikilitic and granular types). Weakly to moderately shocked rocks show high strain-rate deformation and solid-state transformation of minerals to glasses; intensely shocked rocks are converted to rock glasses. Data on an unknown calcium-bearing iron metasilicate are presented.

Oxy-acetylene driven laboratory scale shock tubes for studying blast wave effects

NASA Astrophysics Data System (ADS)

Courtney, Amy C.; Andrusiv, Lubov P.; Courtney, Michael W.

2012-04-01

This paper describes the development and characterization of modular, oxy-acetylene driven laboratory scale shock tubes. Such tools are needed to produce realistic blast waves in a laboratory setting. The pressure-time profiles measured at 1 MHz using high-speed piezoelectric pressure sensors have relevant durations and show a true shock front and exponential decay characteristic of free-field blast waves. Descriptions are included for shock tube diameters of 27-79 mm. A range of peak pressures from 204 kPa to 1187 kPa (with 0.5-5.6% standard error of the mean) were produced by selection of the driver section diameter and distance from the shock tube opening. The peak pressures varied predictably with distance from the shock tube opening while maintaining both a true blast wave profile and relevant pulse duration for distances up to about one diameter from the shock tube opening. This shock tube design provides a more realistic blast profile than current compression-driven shock tubes, and it does not have a large jet effect. In addition, operation does not require specialized personnel or facilities like most blast-driven shock tubes, which reduces operating costs and effort and permits greater throughput and accessibility. It is expected to be useful in assessing the response of various sensors to shock wave loading; assessing the reflection, transmission, and absorption properties of candidate armor materials; assessing material properties at high rates of loading; assessing the response of biological materials to shock wave exposure; and providing a means to validate numerical models of the interaction of shock waves with structures. All of these activities have been difficult to pursue in a laboratory setting due in part to lack of appropriate means to produce a realistic blast loading profile.

Ar-39 - Ar-40 Evidence for an Approximately 4.26 Ga Impact Heating Event on the LL Parent Body

NASA Technical Reports Server (NTRS)

Dixon, E. T.; Bogard, D. D.; Rubin, A. E.

2003-01-01

Miller Range 99301 is a type 6, unbrecciated LL chondrite. MIL 99301 is of interest because some compositional and petrographic features suggest it experienced rather high shock grades, whereas other features suggest it is relatively unshocked. Inconsistent shock indicators could be explained if MIL 99301 was shocked but then partly annealed by heat produced by impacts on the parent body. The hypothesis that MIL 99301 experienced high temperature metamorphism (type 6) followed by a later shock event that heated, but did not melt, the constituent feldspar can be evaluated using (39)Ar-(40)Ar chronology. This is because (39)Ar-(40)Ar ages of shocked ordinary chondrites are generally <4.2 Ga, whereas (39)Ar-(40)Ar ages of unshocked meteorites are generally older, and between 4.52 - 4.38 Ga.

Central venous pressure and shock index predict lack of hemodynamic response to volume expansion in septic shock: a prospective, observational study.

PubMed

Lanspa, Michael J; Brown, Samuel M; Hirshberg, Eliotte L; Jones, Jason P; Grissom, Colin K

2012-12-01

Volume expansion is a common therapeutic intervention in septic shock, although patient response to the intervention is difficult to predict. Central venous pressure (CVP) and shock index have been used independently to guide volume expansion, although their use is questionable. We hypothesize that a combination of these measurements will be useful. In a prospective, observational study, patients with early septic shock received 10-mL/kg volume expansion at their treating physician's discretion after brief initial resuscitation in the emergency department. Central venous pressure and shock index were measured before volume expansion interventions. Cardiac index was measured immediately before and after the volume expansion using transthoracic echocardiography. Hemodynamic response was defined as an increase in a cardiac index of 15% or greater. Thirty-four volume expansions were observed in 25 patients. A CVP of 8 mm Hg or greater and a shock index of 1 beat min(-1) mm Hg(-1) or less individually had a good negative predictive value (83% and 88%, respectively). Of 34 volume expansions, the combination of both a high CVP and a low shock index was extremely unlikely to elicit hemodynamic response (negative predictive value, 93%; P = .02). Volume expansion in patients with early septic shock with a CVP of 8 mm Hg or greater and a shock index of 1 beat min(-1) mm Hg(-1) or less is unlikely to lead to an increase in cardiac index. Copyright © 2012 Elsevier Inc. All rights reserved.

Shock wave interactions in hypervelocity flow

NASA Astrophysics Data System (ADS)

Sanderson, S. R.; Sturtevant, B.

1994-08-01

The impingement of shock waves on blunt bodies in steady supersonic flow is known to cause extremely high local heat transfer rates and surface pressures. Although these problems have been studied in cold hypersonic flow, the effects of dissociative relaxation processes are unknown. In this paper we report a model aimed at determining the boundaries of the possible interaction regimes for an ideal dissociating gas. Local analysis about shock wave intersection points in the pressure-flow deflection angle plane with continuation of singular solutions is the fundamental tool employed. Further, we discuss an experimental investigation of the nominally two-dimensional mean flow that results from the impingement of an oblique shock wave on the leading edge of a cylinder. The effects of variations in shock impingement geometry were visualized using differential interferometry. Generally, real gas effects are seen to increase the range of shock impingement points for which enhanced heating occurs. They also reduce the type 4 interaction supersonic jet width and influence the type 2-3 transition process.

Temporal trend analysis of nurses' knowledge about implantable cardioverter defibrillators.

PubMed

Norekvål, Tone M; Peersen, Lene R L; Seivaag, Kirsten; Fridlund, Bengt; Wentzel-Larsen, Tore

2015-05-01

Although crucial, research on nurses' knowledge on the use of implantable cardioverter defibrillators (ICDs) is scant. The aims of the study were to investigate (i) the level of nurses' knowledge on care of patients with ICDs, (ii) whether knowledge level is related to education and type of hospital where nurses practice and (iii) whether knowledge level changes among nurses over time. We developed a questionnaire comprising 27 items in four parts: (1) Sociodemographics, (2) Technical facts about ICDs, (3) Daily life challenges and (4) Self-evaluation of knowledge. After validation, surveys were conducted during 1-week cardiac educational courses in 2003-2010. In total, 463 nurses working in cardiology-related areas participated, yielding a response rate of 91%. Practical and technical knowledge about ICDs was lacking. Nurses were unaware or did not know that mobile phones can affect the device (80%), that patients are restricted from driving heavy vehicles (69%), and that ICDs can deliver unintended shock therapy (73%). However, they were aware that ICD patients can resume sexual (87%) and physical activity (85%). There were few significant differences with regard to education and type of hospital where nurses practiced, but significant time trends in correct answers regarding kitchen appliances, resumption of physical activity and shock delivery. Over an 8-year period, despite the increased usage of ICDs, overall nurses had a lack of knowledge in relation to specific key clinical issues on the care of ICD patients. As a consequence, these patients may fail to receive qualified care. Future research should assess knowledge of other health care professionals and focus on interventions that increase and maintain an appropriate knowledge level in care of ICD patients. Relevance to clinical practice The level of nurses' knowledge on care of patients with ICDs needs to be systematically raised in order to ensure appropriate counselling and nursing care. © 2014 British Association of Critical Care Nurses.

Type II solar radio bursts, interplanetary shocks, and energetic particle events

NASA Technical Reports Server (NTRS)

Cane, H. V.; Stone, R. G.

1984-01-01

Using the ISEE-3 radio astronomy experiment data 37 interplanetary (IP) type II bursts have been identified in the period September 1978 to December 1981. These events and the associated phenomena are listed. The events are preceded by intense, soft X ray events with long decay times (LDEs) and type II and/or type IV bursts at meter wavelengths. The meter wavelength type II bursts are usually intense and exhibit herringbone structure. The extension of the herringbone structure into the kilometer wavelength range results in the occurrence of a shock accelerated (SA) event. The majority of the interplanetary type II bursts are associated with energetic particle events. These results support other studies awhich indicate that energetic solar particles detected at 1 A.U. are generated by shock acceleration. From a preliminary analysis of the available data there appears to be a high correlation with white light coronal transients.

Type 2 radio bursts, interplanetary shocks and energetic particle events

NASA Technical Reports Server (NTRS)

Cane, H. V.; Stone, R. G.

1982-01-01

Using the ISEE-3 radio astronomy experiment data 37 interplanetary (IP) type II bursts have been identified in the period September 1978 to December 1981. These events and the associated phenomena are listed. The events are preceded by intense, soft X ray events with long decay times (LDEs) and type II and/or type IV bursts at meter wavelengths. The meter wavelength type II bursts are usually intense and exhibit herringbone structure. The extension of the herringbone structure into the kilometer wavelength range results in the occurrence of a shock accelerated (SA) event. The majority of the interplanetary type II bursts are associated with energetic particle events. These results support other studies which indicate that energetic solar particles detected at 1 A.U. are generated by shock acceleration. From a preliminary analysis of the available data there appears to be a high correlation with white light coronal transients.

Characteristics of shock-associated fast-drift kilometric radio bursts

NASA Technical Reports Server (NTRS)

Macdowall, R. J.; Kundu, M. R.; Stone, R. G.

1987-01-01

The existence of a class of fast-drift, shock-associated (SA), kilometric radio bursts which occur at the time of metric type II emission and which are not entirely the kilometric continuation of metric type III bursts has been reported previously (Cane et al., 1981). In this paper unambiguous SA event criteria are established for the purpose of statistically comparing SA events with conventional kilometric type III bursts. Applying these criteria to all long-duration, fast-drift bursts observed by the ISEE-3 spacecraft during a 28-month interval, it is found that more than 70 percent of the events satisfying the criteria are associated with the radio signatures of coronal shocks. If a given event is associated with a metric type II or type IV burst, it is 13 times more likely to satisfy the SA criteria than an event associated only with metric type III activity.

Septic shock with no diagnosis at 24 hours: a pragmatic multicenter prospective cohort study.

PubMed

Contou, Damien; Roux, Damien; Jochmans, Sébastien; Coudroy, Rémi; Guérot, Emmanuel; Grimaldi, David; Ricome, Sylvie; Maury, Eric; Plantefève, Gaëtan; Mayaux, Julien; Mekontso Dessap, Armand; Brun-Buisson, Christian; de Prost, Nicolas

2016-11-06

The lack of a patent source of infection after 24 hours of management of shock considered septic is a common and disturbing scenario. We aimed to determine the prevalence and the causes of shock with no diagnosis 24 hours after its onset, and to compare the outcomes of patients with early-confirmed septic shock to those of others. We conducted a pragmatic, prospective, multicenter observational cohort study in ten intensive care units (ICU) in France. We included all consecutive patients admitted to the ICU with suspected septic shock defined by clinical suspicion of infection leading to antibiotic prescription plus acute circulatory failure requiring vasopressor support. A total of 508 patients were admitted with suspected septic shock. Among them, 374 (74 %) had early-confirmed septic shock, while the 134 others (26 %) had no source of infection identified nor microbiological documentation retrieved 24 hours after shock onset. Among these, 37/134 (28 %) had late-confirmed septic shock diagnosed after 24 hours, 59/134 (44 %) had a condition mimicking septic (septic shock mimicker, mainly related to adverse drug reactions, acute mesenteric ischemia and malignancies) and 38/134 (28 %) had shock of unknown origin by the end of the ICU stay. There were no differences between patients with early-confirmed septic shock and the remainder in ICU mortality and the median duration of ICU stay, of tracheal intubation and of vasopressor support. The multivariable Cox model showed that the risk of day-60 mortality did not differ between patients with or without early-confirmed septic shock. A sensitivity analysis was performed in the subgroup (n = 369/508) of patients meeting the Sepsis-3 definition criteria and displayed consistent results. One quarter of the patients admitted in the ICU with suspected septic shock had no infection identified 24 hours after its onset and almost half of them were eventually diagnosed with a septic shock mimicker. Outcome did not differ between patients with early-confirmed septic shock and other patients.

Metal-saturated sulfide assemblages in NWA 2737: Evidence for impact-related sulfur devolatilization in Martian meteorites

NASA Astrophysics Data System (ADS)

Lorand, Jean-Pierre; Barrat, Jean-Alix; Chevrier, Vincent; Sautter, Violaine; Pont, Sylvain

2012-11-01