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1

MBL Research in the Rio Tinto  

NSDL National Science Digital Library

This web site describes ongoing research of the Marine Biological Laboratory's Astrobiology Group in the Rio Tinto, Spain. The resource includes an image-rich introduction to the Rio Tinto, images of sample sites, information about Rio Tinto biofilms, a list of Rio Tinto references, and a 10-page print-version pdf document including information found on the web site.

Zettler, L. A.; Laboratory, Marine B.

2

Toward a Cultural Advancement of Tinto's Theory  

ERIC Educational Resources Information Center

Despite the broad appeal of Tinto's (1993) theory, it is not well supported by empirical research, especially when applied to minority students. While prior critiques of the theory indicate the need to modify Tinto's concept of "breaking away" when applying the theory to diverse students, research suggests a need for additional refinements. In…

Guiffrida, Douglas A.

2006-01-01

3

Chicano Students: Applying Tinto's and Astin's Theories.  

ERIC Educational Resources Information Center

Chicano student dropout and persistence is discussed in terms of the theories of Tinto and Astin on student integration and involvement. An overview of each theory is presented with references to Chicano student retention, and a review of the literature on Chicano students is provided. The studies reviewed here identified Chicano student…

von Destinon, Mark

4

Extreme environments as Mars terrestrial analogs: The Rio Tinto case  

NASA Astrophysics Data System (ADS)

The geomicrobiological characterization of the Río Tinto (Iberian Pyritic Belt) has recently proven the importance of the iron cycle, not only in the generation of the extreme conditions of the habitat (low pH, high concentration of heavy metals), but also in the maintenance of a high level of microbial diversity. The presence of vast deposits of sulfates and iron oxides on Mars, the main products of the bioleaching of iron containing sulfides found in Río Tinto, and the physico-chemical properties of iron as a source of energy, protection from radiation and oxidative stress as well as pH control, make Río Tinto an interesting Mars terrestrial analog.

Amils, Ricardo; González-Toril, Elena; Fernández-Remolar, David; Gómez, Felipe; Aguilera, Ángeles; Rodríguez, Nuria; Malki, Mustafá; García-Moyano, Antonio; Fairén, Alberto G.; de la Fuente, Vicenta; Luis Sanz, José

2007-02-01

5

Mars Analog Rio Tinto Experiment (MARTE): 2003 Drilling Campaign to Search for a Subsurface Biosphere at Rio Tinto Spain  

NASA Technical Reports Server (NTRS)

The MARTE (Mars Astrobiology Research and Technology Experiment) project, an ASTEP field experiment, is exploring for a hypothesized subsurface anaerobic chemoautotrophic biosphere in the region of the Tinto River- or Rio Tinto- in southwestern Spain. It is also demonstrating technology needed to search for a subsurface biosphere on Mars. The project has three primary objectives: (1) search for and characterize subsurface life at Rio Tinto along with the physical and chemical properties and sustaining energy sources of its environment, (2) perform a high fidelity simulation of a robotic Mars drilling mission to search for life, and (3) demonstrate the drilling, sample handling, and instrument technologies relevant to searching for life on Mars. The simulation of the robotic drilling mission is guided by the results of the aseptic drilling campaign to search for life at Rio Tinto. This paper describes results of the first phase of the aseptic drilling campaign.

Stoker, Carol; Dunagan, Stephen; Stevens, Todd; Amils, Ricardo; Gomez-Elvira, Javier; Fernandez, David; Hall, James; Lynch, Kennda; Cannon, Howard; Zavaleta, Jhony

2004-01-01

6

Mars Analog Rio Tinto Experiment (MARTE): 2003 Drilling Campaign to Search for a Subsurface Biosphere at Rio Tinto Spain  

NASA Astrophysics Data System (ADS)

The results of an drilling experiment to search for a subsurface biosphere in a pyritic mineral deposit at Rio Tinto, Spain, are described. The experiment provides ground truth for a simulation of a Mars drilling mission to search for subsurface life.

Stoker, C.; Dunagan, S.; Stevens, T.; Amils, R.; Gómez-Elvira, J.; Fernández, D.; Hall, J.; Lynch, K.; Cannon, H.; Zavaleta, J.; Glass, B.; Lemke, L.

2004-03-01

7

Student Drop-Out in Distance Education: An Application of Tinto's Model.  

ERIC Educational Resources Information Center

Describes a survey of 356 adult students enrolled in university-level courses at the Open Learning Institute which was conducted to assess the predictive validity of Tinto's theoretical model of student dropout. It was found that, overall, the Tinto model appears to be a useful framework for such investigations. (Author/LRW)

Sweet, Robert

1986-01-01

8

A Path Analytic Validation of Tinto's Theory of College Student Attrition.  

ERIC Educational Resources Information Center

An earlier path analytic study of the predictive validity of Tinto's theory of college student attrition was replicated using an independent sample of students from another university. Tinto conceived of the attrition/retention process as a series of sociopsychological interactions between the characteristics students bring with them to college…

Terenzini, Patrick T.; And Others

9

Audio Interview with Dr. Carol Stoker about MARTE and the Rio Tinto  

NSDL National Science Digital Library

This site features links to broadcast quality audio files and transcripts from an interview with Dr. Carol Stoker about the Mars Analog Research and Technology Experiment (MARTE) which is to take place near the Rio Tinto in Spain. Interview topics include the MARTE expedition, the definition of an extremophile, the significance of the color and pH of Rio Tinto, equipment for the MARTE experiment, the possibility of a Mars drilling mission, and the resemblance of Rio Tinto geochemistry to that of Mars.

Stoker, Carol

2009-06-18

10

Microbial Community Composition and Ecology of an Acidic Aquatic Environment: The Tinto River, Spain  

NSDL National Science Digital Library

This journal article examines the correlation between physicochemical and biological characteristics of the Rio Tinto in Spain. It explains that the extreme acidic environment of the Rio Tinto is due to the metabolic activity of chemolithotrophic microorganisms. The article includes an illustration depicting the geographical position of the Rio Tinto with highlighted sampling and mining sites, tables indicating the values of physio-chemical parameters measured in different seasons and in different rivers, a table listing the taxonomic classification of different microbial groups in the Rio Tinto, a table examining the seasonality of microorganism populations in different sampling sites, phenotypic properties of different sulfur-oxidizing bacteria, and a correlation analysis. A paid subscription to SpringerLink is required to view this article.

Lopez-Archilla, A.; Marin, I.; Amils, R.; Ecology, Microbial

11

Iron world and its astrobiological implications: The Tinto River case  

NASA Astrophysics Data System (ADS)

Extreme ecosystems have recently attracted considerable interest, not only because they prove that life is robust and adaptable, but also because their existence increases the probability of finding life elsewhere in the universe. Most of the best characterized extreme habitats on Earth correspond to geophysical constraints to which opportunistic microorganisms have adapted. However, some extreme acidic environments are unique in that they are the product of biological activity (chemolithotrophy). The Tinto River (Huelva, Southwestern Spain) is an unusual acidic ecosystem (100 km long, mean pH of 2.3) containing a high concentration of heavy metals and an unexpected level of microbial diversity (1,2). In the past, the extreme conditions of the river were considered the result of intense mining activity. The geomicrobiological analysis of the Tinto ecosystem strongly suggests that these conditions are the result of the metabolic activity of chemolithotrophic prokaryotes, mainly iron-oxidizers (3). The system seems to be controlled by iron, which is not only used as an electron donor, but also as an electron acceptor, allowing a full iron cycle to operate. Furthermore, ferric iron is responsible for the maintenance of the constant pH of the ecosystem and can protect the different organisms thriving in its waters from radiation. Laminar, iron-rich stromatolitic formations are generated by the precipitation of different iron minerals on the surface of the biofilms that cover most of the rocks in the river and the riverbed. These structures are similar to ancient massive bioinduced laminated iron bioformations formed long before the first mining activities started in the area 5000 years ago. The existence of these ancient iron-rich deposits formed prior to any known mining activity, under hydrochemical conditions similar to modern deposits, is considered a strong argument in favor of a natural origin of the river (4,5). Recently, the source area of the Tinto ecosystem has been used like an environmental scenario for new technology validation for astrobiology space missions. M.A.R.T.E. (Mars Analog Research Technology Experiment) was a multidisciplinary project for technology development in the NAI framework. REFERENCES 1.- López-Archilla, A.I., Marín, I., Amils, R. (2001) Microbial Ecol., 41: 20-35. 2.- Amaral-Zettler, L.A., Gómez, F., Zettler, E., Keenan, B.G., Amils, R., Sogin, M. (2002) Nature, 417: 137. 3.- González-Toril, E., Gómez, F., Rodríguez, N., Fernández-Remolar, D., Zuluaga, J., Marín, I., Amils, R., (2002) Hydrometall., in press. 4.- Amils, R., González-Toril, E., Gómez, F., Fernández-Remolar, D., Rodríguez, N. (2000) Spring Meeting American Geophysical Society, Abstract B22B-05. 5.- Fernández-Remolar, D.C., Rodríguez, N., Gómez, F., Amils, R. (2003) J. Geophys. Res., 108, No.E7 doi. 10.1029/2002JE001918

Gomez, F.; Amils, A.

2007-08-01

12

Searching for Organics During the Robotic Mars Analog Rio Tinto Drilling Experiment: Ground Truth and Contamination Issues  

NASA Astrophysics Data System (ADS)

The Mars Analog Rio Tinto Experiment (MARTE) performed a simulation of a Mars drilling experiment at the Rio Tinto (Spain). Ground-truth and contamination issues during the distribution of bulk organics and their CN isotopic composition in hematite and go

Bonaccorsi, R.; Stoker, C. R.; Marte Project Science Team

2007-03-01

13

Iberian Pyrite Belt Subsurface Life (IPBSL): searching for life in the Rio Tinto subsurface  

NASA Astrophysics Data System (ADS)

The geomicrobiologica l characterization of Río Tinto (Iberian Pyrite Belt), has proven the importance of the iron and sulfur cycles in generating the extreme conditions of acidity and high concentration of heavy metals of the habitat. It has been hypothesized that the extreme conditions found in the Tinto basin are the product of the subsurface chemolithotrophic metabolism of microorganisms thriving on the high concentrat ion of metal sulfides of the IPB. To test this hypothesis, a drilling project (IPBSL) is currently under development to provide evidence of subsurface microbial activities and the potential resources to support them.

Amils, R.; Gómez, F.; Prieto-Ballesteros, O.; Fernández-Remolar, D.; Parro, V.; Rodríguez-Manfredi, J. A.; Tornos-Arroyo, F.; Timmis, K.; Oggerin, M.; Sánchez-Román, M.; López, F. J.; Fernández, J. P.; Omoregie, E.; Puente-Sánchez, F.; García, M.; Rodríguez, N.

2013-09-01

14

Spectroscopic Raman study of sulphate precipitation sequence in Rio Tinto mining district (SW Spain).  

PubMed

Acidic waters and sulphate-rich precipitates are typical by-products of mining activity such as in Rio Tinto (Huelva, SW Spain). This river drains pyrite mines situated in the Iberian Pyrite Belt which have been in operation since the Bronze Age and probably constitutes the oldest continuously operating mining activity over the world. In the present work, we have used Raman spectroscopy to study a wide range of natural mineral samples collected at Rio Tinto which origin is related to evaporation and mineral transformation processes in a wet and extreme acidic environment. In addition, we simulated the phenomenon of mineral precipitation in controlled conditions by using a simulator developed at the laboratory evaporating natural water collected at Rio Tinto. Also, a series of experiments using the same waters as small droplets have been carried out using micro-Raman technique. The droplets were placed on substrates with different chemical composition and reactivity. The results reveal that the precipitation sequence occurred in Rio Tinto mainly comprises copiapite and coquimbite group minerals followed by several other low hydrated iron sulphates. The experiments carried out on droplets allow estimating with higher accuracy the precipitation sequence. PMID:23818074

Rull, Fernando; Guerrero, Julia; Venegas, Gloria; Gázquez, Fernando; Medina, Jesús

2014-06-01

15

Specific jarosite biomineralization by Purpureocillium lilacinum, an acidophilic fungi isolated from Río Tinto.  

PubMed

Río Tinto (Huelva, southwestern Spain) is an extreme environment with a remarkably constant acidic pH and a high concentration of heavy metals, conditions generated by the metabolic activity of chemolithotrophic microorganisms thriving in the rich complex sulfides of the Iberian Pyrite Belt (IPB). Fungal strains isolated from the Tinto basin were characterized morphologically and phylogenetically. The strain identified as Purpureocillium lilacinum specifically induced the formation of a yellow-ocher precipitate, identified as hydronium-jarosite, an iron sulfate mineral which appears in abundance on the banks of Río Tinto. The biomineral was characterized by X-ray diffraction (XRD) and its formation was observed with high-resolution transmission electron microscopy (TEM) and scanning electron microscopy (SEM) coupled to energy-dispersive X-ray spectroscopy (EDX) microanalysis. Jarosite began to nucleate on the fungal cell wall, associated to the EPS, due to a local increase in the Fe(3+) /Fe(2+) ratio which generated supersaturation. Its formation has been also observed in non-viable cells, although with much less efficiency. The occurrence of P.?lilacinum in an ecosystem with high concentrations of ferric iron and sulfates such as Río Tinto suggests that it could participate in the process of jarosite precipitation, helping to shape and control the geochemical properties of this environment. PMID:23425574

Oggerin, M; Tornos, F; Rodríguez, N; del Moral, C; Sánchez-Román, M; Amils, R

2013-08-01

16

Why do HE Students Drop Out? A test of Tinto's model  

Microsoft Academic Search

This study examined Tinto's (1975) model of student attrition, which suggests that student's dropout decisions are social and academic worlds. The model was tested with path analysis using LISREL8 software (Jöreskog & Sörbom, 1993a) using maximum likelihood estimation. Findings were that the model does not provide an acceptable description of the data. The findings were based on a global test

Vivienne Brunsden; Mark Davies; Mark Shevlin; Maeve Bracken

2000-01-01

17

Attrition at a Commuter Institution: A Path Analytic Validation of Tinto's Theoretical Model of College Withdrawal.  

ERIC Educational Resources Information Center

This study tested Pascarella's reconceptualization of Tinto's model of the persistence/withdrawal process for use in a non-residential institution. Subjects (n=372) were college freshmen who had attended freshmen orientation and had completed an opinionnaire both during orientation and at the end of their first year in a medium-sized, urban…

Allen, David F.

18

Fast-Turnoff Transient Electromagnetic (TEM) Field Study at the Mars Analog Site of Rio Tinto, Spain  

NASA Astrophysics Data System (ADS)

This report describes a Fast-Turnoff Transient Electromagnetic (TEM) study at the Peña de Hierro ("Berg of Iron") field area of the Mars Analog Research and Technology Experiment (MARTE), near the towns Rio Tinto and Nerva, Andalucia region, Spain.

Jernsletten, J. A.

2005-03-01

19

From río tinto to Mars: the terrestrial and extraterrestrial ecology of acidophiles.  

PubMed

The recent geomicrobiological characterization of Río Tinto, Iberian Pyrite Belt (IPB), has proven the importance of the iron cycle, not only in generating the extreme conditions of the habitat (low pH, high concentration of toxic heavy metals) but also in maintaining the high level of microbial diversity, both prokaryotic and eukaryotic, detected in the water column and the sediments. The extreme conditions of the Tinto basin are not the product of industrial contamination but the consequence of the presence of an underground bioreactor that obtains its energy from the massive sulfide minerals of the IPB. To test this hypothesis, a drilling project was carried out to intersect ground waters that interact with the mineral ore in order to provide evidence of subsurface microbial activities and the potential resources to support these activities. The oxidants that drive the system appear to come from the rock matrix, contradicting conventional acid mine drainage models. These resources need only groundwater to launch microbial metabolism. There are several similarities between the vast deposits of sulfates and iron oxides on Mars and the main sulfide-containing iron bioleaching products found in the Tinto. Firstly, the short-lived methane detected both in Mars' atmosphere and in the sediments and subsurface of the IPB and secondly, the abundance of iron, common to both. The physicochemical properties of iron make it a source of energy, a shield against radiation and oxidative stress as well as a natural pH controller. These similarities have led to Río Tinto's status as a Mars terrestrial analogue. PMID:22050821

Amils, R; González-Toril, E; Aguilera, A; Rodríguez, N; Fernández-Remolar, D; Gómez, F; García-Moyano, A; Malki, M; Oggerin, M; Sánchez-Andrea, I; Sanz, J L

2011-01-01

20

Hydrogeochemical characteristics of the Tinto and Odiel Rivers (SW Spain). Factors controlling metal contents.  

PubMed

The Tinto and Odiel Rivers are strongly affected by acid mine drainage (AMD) due to the intense sulphide mining developed in their basins over the past 5000 years. In this study the results obtained from a weekly sampling in both rivers, before their mouth in the Ría of Huelva, over three and a half years of control are analysed. In the Tinto River, the concentrations of sulphates, Al, Cd, Co, Li and Zn are double to those of the Odiel as a consequence of lower dilution. However, the concentration of Fe in the Odiel River is 20 times lower, since the precipitation of Fe oxyhydroxysulphates caused by neutralisation processes is more intense. Lower As, Cr, Cu and Pb concentrations are also found in the Odiel River as, to a greater or lesser extent, they are sorbed and/or coprecipitated with Fe. Other elements such as Be, Mn, Ni and Mg show similar values in both systems, which is ascribed to lithological factors. The seasonal evolution of contaminants is typical of rivers affected by AMD, reaching a maximum in autumn due to the dissolution of evaporitic salts precipitated during the summer. Nevertheless, in the Tinto River, Ca, Na and Sr show a strong increase during the summer, probably due to a greater water interaction with marly materials, through which the last reach of the river flows. Barium has a different behaviour from the rest of the metals and its concentration seems to be controlled by the solubility of barite. Iron, As and Pb show different behaviours in both rivers, those for Fe and As possibly linked to the prevalence of different dissolved species of Fe. The different Pb pattern is probably due to the control of Pb solubility by anglesite or other minerals rich in Pb in the Tinto River. PMID:17207846

Cánovas, C R; Olías, M; Nieto, J M; Sarmiento, A M; Cerón, J C

2007-02-01

21

Scale-integrated spectral characterisation of mineralogical analogues to Mars at Rio Tinto  

NASA Astrophysics Data System (ADS)

Iron-sulfur assemblages within the Rio Tinto basin of Huelva province in Spain show mineralogical similarities to sites on the surface of Mars as determined by orbital and lander datasets. Exploration of Mars surface environments is intermittent and resolution-limited, and additional layers of information available for terrestrial analogue sites may extend incomplete planetary datasets. Characterising mineralogy in satellite, field and laboratory reflectance spectra of Rio Tinto sites can determine how accurately Mars-relevant mineralogies are represented in orbital data. Comparisons with Mars datasets, such as OMEGA and CRISM, can provide insights into planetary surface conditions. Interaction between materials in field mixtures can lead to potential interferences between endmembers and/or offsets in spectral features, which can obscure or hinder the identification of certain minerals. Such interactions can be difficult to predict on the basis of library spectra collected using pure materials. Determination of which diagnostic spectral features can be identified in field mixtures is an advantage of collecting data in real world environments, and can be used to aid interpretation of planetary datasets. This study utilizes the dynamic sulfur and iron deposits of Rio Tinto as an analogue of Mars sites such as Meridiani Planum, using the many scales of observation available for the terrestrial sites as a means of extending our view of Mars surface conditions from the orbital view to which we are frequently limited.

Gleeson, Damhnait; Fernandez-Remolar, David; Martin, Patrick; Moissl, Richard; Ruiz, Vicente

2013-04-01

22

Heavy metal anomalies in the Tinto and Odiel River and estuary system, Spain  

USGS Publications Warehouse

The Tinto and Odiel rivers drain 100 km from the Rio Tinto sulphide mining district, and join at a 20-km long estuary entering the Atlantic Ocean. A reconnaissance study of heavy metal anomalies in channel sand and overbank mud of the river and estuary by semi-quantitative emission dc-arc spectrographic analysis shows the following upstream to downstream ranges in ppm (??g g-1): As 3,000 to <200, Cd 30 to <0.1, Cu 1,500 to 10, Pb 2,000 to <10, Sb 3000 to <150, and Zn 3,000 to <200. Organic-rich (1.3-2.6% total organic carbon, TOC), sandysilty overbank clay has been analyzed to represent suspended load materials. The high content of heavy metals in the overbank clay throughout the river and estuary systems indicates the importance of suspended sediment transport for dispersing heavy metals from natural erosion and anthropogenic mining activities of the sulfide deposit. The organic-poor (0.21-0.37% TOC) river bed sand has been analyzed to represent bedload transport of naturally-occurring sulfide minerals. The sand has high concentrations of metals upstream but these decrease an order of magnitude in the lower estuary. Although heavy metal contamination of estuary mouth beach sand has been diluted to background levels estuary mud exhibits increased contamination apparently related to finer grain size, higher organic carbon content, precipitation of river-borne dissolved solids, and input of anthropogenic heavy metals from industrial sources. The contaminated estuary mud disperses to the inner shelf mud belt and offshore suspended sediment, which exhibit metal anomalies from natural erosion and mining of upstream Rio Tinto sulphide lode sources (Pb, Cu, Zn) and industrial activities within the estuary (Fe, Cr, Ti). Because heavy metal contamination of Tinto-Odiel river sediment reaches or exceeds the highest levels encountered in other river sediments of Spain and Europe, a detailed analysis of metals in water and suspended sediment throughout the system, and epidemiological analysis of heavy metal effects in humans is appropriate. ?? 1993 Estuarine Research Federation.

Nelson, C. H.; Lamothe, P. J.

1993-01-01

23

Identification of Hydrated Sulfates Collected in the Northern Rio Tinto Valley by Reflectance and Raman Spectroscopy  

NASA Technical Reports Server (NTRS)

OMEGA recently identified spectral signatures of kieserite, gypsum, and other polyhydrated sulfates at multiple locations on the surface of Mars [1,2]. The presence of sulfates was confirmed through in situ spectroscopy by MER Opportunity [3]. An approach to validate these interpretations is to collect corresponding spectral data from sulfate-rich terrestrial analog sites. The northern Rio Tinto Valley near Nerva, Spain, is a good Martian analog locale because it features extensive seasonal sulfate mineralization driven by highly acidic waters [4]. We report on mineralogical compositions identified by field VNIR spectroscopy and laboratory Raman spectroscopy.

Chemtob, S. M.; Arvidson, R. E.; Fernandez-Remolar, D. C.; Amils, R.; Morris, R. V.; Ming, D. W.; Prieto-Ballesteros, O.; Mustard, J. F.; Hutchinson, L.; Stein, T. C.; Donovan, C. E.; Fairchild, G. M.; Friedlander, L. R.; Karas, N. M.; Klasen, N.; Mendenhall, M. P.; Robinson, E. M.; Steinhardt, S. E.; Weber, L. R.

2006-01-01

24

Underground habitats in the Río Tinto basin: a model for subsurface life habitats on Mars.  

PubMed

A search for evidence of cryptic life in the subsurface region of a fractured Paleozoic volcanosedimentary deposit near the source waters of the Río Tinto River (Iberian pyrite belt, southwest Spain) was carried out by Mars Astrobiology Research and Technology Experiment (MARTE) project investigators in 2003 and 2004. This conventional deep-drilling experiment is referred to as the MARTE ground truth drilling project. Boreholes were drilled at three sites, and samples from extracted cores were analyzed with light microscopy, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy. Core leachates were analyzed with ion chromatography, and borehole fluids were analyzed with ion and gas chromatography. Key variables of the groundwater system (e.g., pO(2), pH, and salinity) exhibit huge ranges probably due to surficial oxygenation of overall reducing waters, physical mixing of waters, and biologically mediated water-rock interactions. Mineral distribution is mainly driven by the pH of subsurface solutions, which range from highly acidic to neutral. Borehole fluids contain dissolved gases such as CO(2), CH(4), and H(2). SEM-EDS analyses of core samples revealed evidence of microbes attacking pyrite. The Río Tinto alteration mechanisms may be similar to subsurface weathering of the martian crust and provide insights into the possible (bio)geochemical cycles that may have accompanied underground habitats in extensive early Mars volcanic regions and associated sulfide ores. PMID:19105758

Fernández-Remolar, David C; Prieto-Ballesteros, Olga; Rodríguez, Nuria; Gómez, Felipe; Amils, Ricardo; Gómez-Elvira, Javier; Stoker, Carol R

2008-10-01

25

Underground Habitats in the Río Tinto Basin: A Model for Subsurface Life Habitats on Mars  

NASA Astrophysics Data System (ADS)

A search for evidence of cryptic life in the subsurface region of a fractured Paleozoic volcanosedimentary deposit near the source waters of the Río Tinto River (Iberian pyrite belt, southwest Spain) was carried out by Mars Astrobiology Research and Technology Experiment (MARTE) project investigators in 2003 and 2004. This conventional deep-drilling experiment is referred to as the MARTE ground truth drilling project. Boreholes were drilled at three sites, and samples from extracted cores were analyzed with light microscopy, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy. Core leachates were analyzed with ion chromatography, and borehole fluids were analyzed with ion and gas chromatography. Key variables of the groundwater system (e.g. , pO2, pH, and salinity) exhibit huge ranges probably due to surficial oxygenation of overall reducing waters, physical mixing of waters, and biologically mediated water-rock interactions. Mineral distribution is mainly driven by the pH of subsurface solutions, which range from highly acidic to neutral. Borehole fluids contain dissolved gases such as CO2, CH4, and H2. SEM-EDS analyses of core samples revealed evidence of microbes attacking pyrite. The Río Tinto alteration mechanisms may be similar to subsurface weathering of the martian crust and provide insights into the possible (bio)geochemical cycles that may have accompanied underground habitats in extensive early Mars volcanic regions and associated sulfide ores.

Fernández-Remolar, David C.; Prieto-Ballesteros, Olga; Rodríguez, Nuria; Gómez, Felipe; Amils, Ricardo; Gómez-Elvira, Javier; Stoker, Carol R.

2008-10-01

26

Raman and Mössbauer Spectroscopic Characterisation of Sulfate Minerals from the Mars Analogue Sites at Rio Tinto and Jaroso Ravine, Spain  

NASA Astrophysics Data System (ADS)

A combined Raman and Mössbauer spectroscopic study of natural sulfates from two martian analogues, Rio Tinto and Jaroso Ravine (Spain), is presented. The work was performed in similar experimental conditions to those envisaged for Mars surface within the ExoMars mission.

Rull, F.; Fleischer, I.; Martinez-Frias, J.; Sanz, A.; Upadhyay, C.; Klingelhöfer, G.

2008-03-01

27

Characterization of a Subsurface Biosphere in a Massive Sulfide Deposit At Rio Tinto, Spain: Implications For Extant Life On Mars  

NASA Technical Reports Server (NTRS)

The recent discovery of abundant sulfate minerals, particularly Jarosite by the Opportunity Rover at Sinus Merdiani on Mars has been interpreted as evidence for an acidic lake or sea on ancient Mars [1,2], since the mineral Jarosite is soluble in liquid water at pH above 4. The most likely mechanism to produce sufficient protons to acidify a large body of liquid water is near surface oxidation of pyrite rich deposits [3]. The acidic waters of the Rio Tinto, and the associated deposits of Hematite, Goethite, and Jarosite have been recognized as an important chemical analog to the Sinus Merdiani site on Mars [4]. The Rio Tinto is a river in southern Spain that flows 100 km from its source in the Iberian pyrite belt, one of the Earth's largest Volcanically Hosted Massive Sulfide (VHMS) provinces, into the Atlantic ocean. The river originates in artesian springs emanating from ground water that is acidified by the interaction with subsurface pyrite ore deposits. The Mars Analog Rio Tinto Experiment (MARTE) has been investigating the hypothesis that a subsurface biosphere exists at Rio Tinto living within the VHMS deposit living on chemical energy derived from sulfur and iron minerals. Reduced iron and sulfur might provide electron donors for microbial metabolism while in situ oxidized iron or oxidants entrained in recharge water might provide electron acceptors.

Stoker, C. R.; Stevens, T.; Amils, R.; Gomez-Elvira, J.; Rodriguez, N.; Gomez, F.; Gonzalez-Toril, E.; Aguilera, A.; Fernandez-Remolar, D.; Dunagan, S.

2005-01-01

28

Characterization of a Subsurface Biosphere in a Massive Sulfide Deposits at Rio Tinto, Spain: Implications for Extant Life on Mars  

NASA Technical Reports Server (NTRS)

The recent discovery of abundant sulfate minerals, particularly Jarosite by the Opportunity Rover at Sinus Merdiani on Mars has been interpreted as evidence for an acidic lake or sea on ancient Mars [1,2], since the mineral Jarosite is soluble in liquid water at pH above 4. The most likely mechanism to produce sufficient protons to acidify a large body of liquid water is near surface oxidation of pyrite rich deposits [3]. The acidic waters of the Rio Tinto, and the associated deposits of Hematite, Goethite, and Jarosite have been recognized as an important chemical analog to the Sinus Merdiani site on Mars [4]. The Rio Tinto is a river in southern Spain that flows 100 km from its source in the Iberian pyrite belt, one of the Earth s largest Volcanically Hosted Massive Sulfide (VHMS) provinces, into the Atlantic ocean. The river originates in artesian springs emanating from ground water that is acidified by the interaction with subsurface pyrite ore deposits. The Mars Analog Rio Tinto Experiment (MARTE) has been investigating the hypothesis that a subsurface biosphere exists at Rio Tinto living within the VHMS deposit living on chemical energy derived from sulfur and iron minerals. Reduced iron and sulfur might provide electron donors for microbial metabolism while in situ oxidized iron or oxidants entrained in recharge water might provide electron acceptors.

Stoker, C. R.; Stevens, T.; Amils, R.; Gomez-Elvira, J.; Rodriquez, N.; Gomez, F.; Gonzalez-Toril, E.; Aguilera, A.; Fernandez-Remolar, D.; Dunagan, S.

2005-01-01

29

Inorganic arsenic speciation at river basin scales: The Tinto and Odiel Rivers in the Iberian Pyrite Belt, SW Spain  

Microsoft Academic Search

The Tinto and Odiel rivers are heavily affected by acid mine drainage from mining areas in the Iberian Pyrite Belt. In this work we have conducted a study along these rivers where surface water samples have been collected. Field measurements, total dissolved metals and Fe and inorganic As speciation analysis were performed. The average total concentration of As in the

A. M. Sarmiento; J. M. Nieto; C. Casiot; F. Elbaz-Poulichet; M. Egal

2009-01-01

30

Multidisciplinary integrated field campaign to an acidic Martian Earth analogue with astrobiological interest: Rio Tinto  

NASA Astrophysics Data System (ADS)

Recently reported results from latest Mars Orbiters and Rovers missions are transforming our opinion about the red planet. That dry and inhospitable planet reported in the past is becoming a wetter planet with high probabilities of water existence in the past. Nowadays, some results seem to indicate the presence of water beneath the Mars surface. But also mineralogy studies by NASA Opportunity Rover report iron oxides and hydroxides precipitates on Endurance Crater. Sedimentary deposits have been identified at Meridiani Planum. These deposits must have generated in a dune aqueous acidic and oxidizing environment. Similarities appear when we study Rio Tinto, and acidic river under the control of iron. The discovery of extremophiles on Earth widened the window of possibilities for life to develop in the Universe, and as a consequence on Mars and other planetary bodies with astrobiological interest. The compilation of data produced by the ongoing missions offers an interested view for life possibilities to exist: signs of an early wet Mars and rather recent volcanic activity as well as ground morphological characteristics that seem to be promoted by liquid water. The discovery of important accumulations of sulfates and the existence of iron minerals such as jarosite in rocks of sedimentary origin has allowed specific terrestrial models to come into focus. Río Tinto (Southwestern Spain, Iberian Pyritic Belt) is an extreme acidic environment, product of the chemolithotrophic activity of micro-organisms that thrive in the massive pyrite-rich deposits of the Iberian Pyritic Belt. Some particular protective environments should house the organic molecules and bacterial life forms in harsh environments such as Mars surface supporting microniches inside precipitated minerals or inside rocks. Terrestrial analogues could help us to afford the comprehension of habitability (on other planetary bodies). We are reporting here the multidisciplinary study of some endolithic niches inside salt deposits used by phototrophs for taking advantage of sheltering particular light wavelengths. These acidic salts deposits located in Río Tinto shelter life forms that are difficult to visualize by eye. This interdisciplinary field analogue campaign was conducted in the framework of the CAREX FP7 EC programme.

Gómez, F.; Walter, N.; Amils, R.; Rull, F.; Klingelhöfer, A. K.; Kviderova, J.; Sarrazin, P.; Foing, B.; Behar, A.; Fleischer, I.; Parro, V.; Garcia-Villadangos, M.; Blake, D.; Martin Ramos, J. D.; Direito, S.; Mahapatra, P.; Stam, C.; Venkateswaran, K.; Voytek, M.

2011-07-01

31

Gulf/RTR oil sands extraction process. [Gulf/Rio Tinto TIL Holding S. A  

SciTech Connect

The activities carried out and the results obtained from a 15 tons/hour oil sands extraction pilot plant operated in Fort McMurray in Northern Alberta are described. The process is the Rio Tinto TIL Holding S.A. (RTR)/Gulf Canada Lt. Oil Sands Extraction Process. It is a modified hot water extraction process. It is used to extract bitumen from Athabasca oil sands. The test ran from July to December 1981 through ambient conditions ranging from plus 38/sup 0/C to minus 30/sup 0/C (100/sup 0/F to -22/sup 0/F). The process, the on-site facilities, the test program, an analysis of plant performance, an appraisal of the process economics, and an evaluation of its potential application are described.

Logan, A.; Devenny, D.; Porcari, G.; Corti, A.

1984-06-01

32

Application of a systemic approach to the study of pollution of the Tinto and Odiel rivers (Spain).  

PubMed

The province of Huelva in the SW of Spain presents high environmental contrasts: together with the great abundance of natural spaces, it shows the impacts of historical natural resources exploitation processes. In the Ria of Huelva, the effluents of the chemical industries must be added to the contaminating inputs of the Tinto and Odiel rivers, coming from the acid drainage of the mines located in the Iberian Pyrite Belt. This forced the Environmental Agency (AMA) to elaborate in 1987 an Effluent Remediation Plan in order to negate unacceptable environmental impacts. The application of a "grey box" systemic analysis to the AMD pollution, undergone by the Tinto and Odiel rivers has allowed to set a conclusive explanation of the sampling results observed for a period of 11 years, thus making available an overall view of the polluting process and, above all, an explanation of its partial aspects. PMID:15869201

Sainz, A; Grande, J A; De La Torre, M L

2005-03-01

33

Exploration of a Subsurface Biosphere in a Volcanic Massive Sulfide: Results of the Mars Analog Rio Tinto Drilling Experiment  

NASA Astrophysics Data System (ADS)

Biological systems on Earth require three key ingredients-- liquid water, an energy source, and a carbon source, that are found in very few extraterrestrial environments. Previous examples of independent subsurface ecosystems have been found only in basalt aquifers. Such lithotrophic microbial ecosystems (LME) have been proposed as models for steps in the early evolution of Earth's biosphere and for potential biospheres on other planets where the surface is uninhabitable, such as Mars and Europa.. The Mars Analog Rio Tinto Experiment (MARTE) has searched in a volcanic massive sulfide deposit in Rio Tinto Spain for a subsurface biosphere capable of living without sunlight or oxygen and found a subsurface ecosystem driven by the weathering of the massive sulfide deposit (VMS) in which the rock matrix provides sufficient resources to support microbial metabolism, including the vigorous production of H2 by water-rock interactions. Microbial production of methane and sulfate occurred in the sulfide orebody and microbial production of methane and hydrogen sulfide continued in an anoxic plume downgradient from the sulfide ore. Organic carbon concentrations in the parent rock were too low to support microbes. The Rio Tinto system thus represents a new type of subsurface ecosystem with strong relevance for exobiological studies. Commercial drilling was used to reach the aquifer system at 100 m depth and conventional laboratory techniques were used to identify and characterize the biosphere. Then, the life search strategy that led to successful identification of this biosphere was applied to the development of a robotic drilling, core handling, inspection, subsampling, and life detection system built on a prototype planetary lander that was deployed in Rio Tinto Spain in September 2005 to test the capability of a robotic drilling system to search for subsurface life. A remote science team directed the simulation and analyzed the data from the MARTE robotic drill. The results of this experiment have important implications for the strategy for searching for life on Mars.

Stoker, C. R.; Stevens, T.; Amils, R.; Fernandez, D.

2005-12-01

34

Application of cluster analysis to the geochemistry zonation of the estuary waters in the Tinto and Odiel rivers (Huelva, Spain).  

PubMed

The combination of acid water from mines, industrial effluents and sea water plays a determining role in the evolutionary process of the chemical makeup of the water in the estuary of the Tinto and Odiel rivers. This estuary is in the southwest of the Iberian Peninsula and is one of the estuarine systems on the northwest coast of the Gulf of Cádiz. From the statistical treatment of data obtained by analyzing samples of water from this system, which is affected by industrial and mining pollution processes, we can see how the sampling points studied form two large groups depending on whether they receive tidal or fluvial influences. Fluvial input contributes acid water with high concentrations of heavy metal, whereas industrial effluents are responsible for the presence of phosphates, silica and other nutrients. The estuarine system of the Tinto and Odiel Rivers can be divided into three areas--the Tinto estuary, the Odiel estuary and the area of confluence--based on the physical--chemical characteristics of the water. PMID:12901168

Grande, José Antonio; Borrego, José; de la Torre, Maria Luisa; Sáinz, A

2003-06-01

35

Raman spectroscopy of the system iron(III)-sulfuric acid-water: an approach to Tinto River's (Spain) hydrogeochemistry.  

PubMed

Acid mine drainage is formed when pyrite (FeS(2)) is exposed and reacts with air and water to form sulfuric acid and dissolved iron. Tinto River (Huelva, Spain) is an example of this phenomenon. In this study, Raman spectroscopy has been used to investigate the speciation of the system iron(III)-sulfuric acid-water as an approach to Tinto River's aqueous solutions. The molalities of sulfuric acid (0.09 mol/kg) and iron(III) (0.01-1.5 mol/kg) were chosen to mimic the concentration of the species in Tinto River waters. Raman spectra of the solutions reveal a strong iron(III)-sulfate inner-sphere interaction through the nu(1) sulfate band at 981 cm(-1) and its shoulder at 1005 cm(-1). Iron(III)-sulfate interaction may also be facilitated by hydrogen bonds and monitored in the Raman spectra through the symmetric stretching band of bisulfate at 1052 cm(-1) and a shoulder at 1040 cm(-1). Other bands in the low-frequency region of the Raman spectra are attributed to the hydrogen-bonded complexes formation as well. PMID:17869164

Sobron, P; Rull, F; Sobron, F; Sanz, A; Medina, J; Nielsen, C J

2007-12-15

36

Acid mine drainage in the Iberian Pyrite Belt: 1. Hydrochemical characteristics and pollutant load of the Tinto and Odiel rivers.  

PubMed

Acid mine drainage in the Iberian Pyrite Belt is probably the worst case in the world of surface water pollution associated with mining of sulphide mineral deposits. The Iberian Pyrite Belt is located in SW Iberian Peninsula, and it has been mined during the last 4,500 years. The central and eastern part of the Iberian Pyrite Belt is drained by the Tinto and Odiel rivers, which receive most of the acidic leachates from the mining areas. As a result, the main channels of the Tinto and Odiel rivers are very rich in metals and highly acidic until reaching the Atlantic Ocean. A significant amount of the pollutant load transported by these two rivers is delivered during the rainy season, as is usual in rivers of Mediterranean climate regions. Therefore, in order to have an accurate estimation of the pollutant loads transported by the Tinto and Odiel rivers, a systematic sampling on a weekly basis and a high temporal resolution sampling of floods events were both performed. Results obtained show that metal fluxes are strongly dependent on the study period, highlighting the importance of inter-annual studies involving dry and wet years. PMID:23589239

Nieto, Jose M; Sarmiento, Aguasanta M; Canovas, Carlos R; Olias, Manuel; Ayora, Carlos

2013-11-01

37

Searching for Life Underground: An Analysis of Remote Sensing Observations of a Drill Core from Rio Tinto, Spain for Mineralogical Indications of Biological Activity  

NASA Technical Reports Server (NTRS)

Water is unstable on the surface of Mars, and therefore the Martian surface is not likely to support life. It is possible, however, that liquid water exists beneath the surface of Mars, and thus life might also be found in the subsurface. Subsurface life would most likely be microbial, anaerobic, and chemoautotrophic; these types of biospheres on Earth are rare, and not well understood. Finding water and life are high priorities for Mars exploration, and therefore it is important that we learn to explore the subsurface robotically, by drilling. The Mars Analog Rio Tinto Experiment (MARTE), has searched successfully for a subsurface biosphere at Rio Tinto, Spain [1,2,3,4]. The Rio Tinto study site was selected to search for a subsurface biosphere because the extremely low pH and high concentrations of elements such as iron and copper in the Tinto River suggest the presence of a chemoautotrophic biosphere in the subsurface beneath the river. The Rio Tinto has been recognized as an important mineralogical analog to the Sinus Meridiani site on Mars [5].

Battler, M.; Stoker, C.

2005-01-01

38

Mars Sulfate Formation Sourced in Sulfide-Enriched Subsurface Fluids: The Rio Tinto Model  

NASA Technical Reports Server (NTRS)

The extensive evidence for sulfate deposits on Mars provided by analyses of MER and Mars Express data shows that the sulfur played an essential role in the geochemical cycles of the planet, including reservoirs in the atmosphere, hydro-sphere and geosphere. Overall the data are consistent with a fluvial/lacustrine-evaporative origin of at least some of the sulfate deposits, with mineral precipitation through oversaturation of salty acidic fluids enriched in sulfates. This scenario requires reservoirs of sulfur and associated cations, as well as an acidic and oxidizing hydrochemistry which could be provided by surface and subsurface catching of meteoric waters resulting in the presence of sulfur-bearing gases and steam photochemistry. In this work we suggest a new scenario for the extensive generation of sulfates in Mars based on the observation of seasonal changes in the redox and pH of subsurface waters enriched in sulfur that supply the acidic Mars process analog of Rio Tinto. This model considers the long-term subsurface storage of sulfur during most of Noachian and its release from the late Noachian to Hesperian time through weathering by meteoric fluids that would acidify and oxidize the sulfur bearing compounds stored in the subsurface.

Fernandez-Remolar, D. C.; Prieto-Ballesteros, O.; Osburn, M. R.; Gomez-Ortiz, D.; Arvidson, R. E.; Morris, R. V.; Ming, D.; Amils, R.; Friendlander, L. R.

2007-01-01

39

Contrasting Microbial Community Assembly Hypotheses: A Reconciling Tale from the R?o Tinto  

PubMed Central

Background The Río Tinto (RT) is distinguished from other acid mine drainage systems by its natural and ancient origins. Microbial life from all three domains flourishes in this ecosystem, but bacteria dominate metabolic processes that perpetuate environmental extremes. While the patchy geochemistry of the RT likely influences the dynamics of bacterial populations, demonstrating which environmental variables shape microbial diversity and unveiling the mechanisms underlying observed patterns, remain major challenges in microbial ecology whose answers rely upon detailed assessments of community structures coupled with fine-scale measurements of physico-chemical parameters. Methodology/Principal Findings By using high-throughput environmental tag sequencing we achieved saturation of richness estimators for the first time in the RT. We found that environmental factors dictate the distribution of the most abundant taxa in this system, but stochastic niche differentiation processes, such as mutation and dispersal, also contribute to observed diversity patterns. Conclusions/Significance We predict that studies providing clues to the evolutionary and ecological processes underlying microbial distributions will reconcile the ongoing debate between the Baas Becking vs. Hubbell community assembly hypotheses.

Palacios, Carmen; Zettler, Erik; Amils, Ricardo; Amaral-Zettler, Linda

2008-01-01

40

Field rates for natural attenuation of arsenic in Tinto Santa Rosa acid mine drainage (SW Spain).  

PubMed

Reactive transport modelling of the main processes related to the arsenic natural attenuation observed in the acid mine drainage (AMD) impacted stream of Tinto Santa Rosa (SW Spain) was performed. Despite the simplicity of the kinetic expressions used to deal with arsenic attenuation processes, the model reproduced successfully the major chemical trends observed along the acid discharge. Results indicated that the rate of ferrous iron oxidation was similar to the one obtained in earlier field studies in which microbial catalysis is reported to occur. With regard to the scaled arsenic oxidation rate, it is one order of magnitude faster than the values obtained under laboratory conditions suggesting the existence of a catalytic agent in the natural system. Schwertmannite precipitation rate, which was represented by a simple kinetic expression relying on Fe(III) and pH, was in the range calculated for other AMD impacted sites. Finally, the obtained distribution coefficients used for representing arsenic sorption onto Fe(III) precipitates were lower than those deduced from reported laboratory data. This discrepancy is attributed to a decrease in the schwertmannite arsenate sorption capacity as sulphate increases in the solution. PMID:20153577

Asta, Maria P; Ayora, Carlos; Acero, Patricia; Cama, Jordi

2010-05-15

41

Enzyme-Cascade Analysis of the Rio Tinto Subsurface Environment: A Biosensor Experiment  

NASA Technical Reports Server (NTRS)

The Portable Test System (PTS), designed & developed by Charles Rivers Laboratories, Inc. (Charleston, SC) is a portable instrument that was designed to perform analysis of enzymatic assays related to rapid assessment of microbial contamination (Wainwright, 2003). The enzymatic cascade of Limulus Amebocyte Lysate (LAL) is known to be one of the most sensitive techniques available for microbial detection, enabling the PTS to be evaluated as a potential life detection instrument for in situ Astrobiology missions. In the summer of 2003 the system was tested as a part of the Mars Astrobiology Research and Technology Experiment (MARTE) ground truth science campaign in the Rio Tinto Analogue environment near Nerva, Spain. The preliminary results show that the PTS analysis correlates well with the contamination control tests and the more traditional lab-based biological assays performed during the MARTE field mission. Further work will be conducted on this research during a second field campaign in 2004 and a technology demonstration of a prototype instrument that includes autonomous sample preparation will occur in 2005.

McKay, David S.; Lynch, Kennda; Wainwright, Norman; Child, Alice; Williams, Kendra; McKay, David; Amils, Ricardo; Gonzalez, Elena; Stoker, Carol

2004-01-01

42

Microbial Diversity in Anaerobic Sediments at R?o Tinto, a Naturally Acidic Environment with a High Heavy Metal Content?†  

PubMed Central

The Tinto River is an extreme environment located at the core of the Iberian Pyritic Belt (IPB). It is an unusual ecosystem due to its size (100 km long), constant acidic pH (mean pH, 2.3), and high concentration of heavy metals, iron, and sulfate in its waters, characteristics that make the Tinto River Basin comparable to acidic mine drainage (AMD) systems. In this paper we present an extensive survey of the Tinto River sediment microbiota using two culture-independent approaches: denaturing gradient gel electrophoresis and cloning of 16S rRNA genes. The taxonomic affiliation of the Bacteria showed a high degree of biodiversity, falling into 5 different phyla: Proteobacteria, Firmicutes, Bacteroidetes, Acidobacteria, and Actinobacteria; meanwhile, all the Archaea were affiliated with the order Thermoplasmatales. Microorganisms involved in the iron (Acidithiobacillus ferrooxidans, Sulfobacillus spp., Ferroplasma spp., etc.), sulfur (Desulfurella spp., Desulfosporosinus spp., Thermodesulfobium spp., etc.), and carbon (Acidiphilium spp., Bacillus spp., Clostridium spp., Acidobacterium spp., etc.) cycles were identified, and their distribution was correlated with physicochemical parameters of the sediments. Ferric iron was the main electron acceptor for the oxidation of organic matter in the most acid and oxidizing layers, so acidophilic facultative Fe(III)-reducing bacteria appeared widely in the clone libraries. With increasing pH, the solubility of iron decreases and sulfate-reducing bacteria become dominant, with the ecological role of methanogens being insignificant. Considering the identified microorganisms—which, according to the rarefaction curves and Good's coverage values, cover almost all of the diversity—and their corresponding metabolism, we suggest a model of the iron, sulfur, and organic matter cycles in AMD-related sediments.

Sanchez-Andrea, Irene; Rodriguez, Nuria; Amils, Ricardo; Sanz, Jose Luis

2011-01-01

43

Metal uptake and distribution in cultured seedlings of Nerium oleander L. (Apocynaceae) from the Río Tinto (Huelva, Spain).  

PubMed

Nerium oleander L. (Apocynaceae) is a micro-nano phanerophyte that grows in the riverbanks of the Río Tinto basin (Southwest Iberian Peninsula). The waters and soils of the Río Tinto area are highly acidic and have high concentrations of heavy metals. In this environment, N. oleander naturally grows in both extreme acidic (EA) and less extreme acidic (LEA) water courses, excluding, and bioindicating certain metals. In this work, we compared and evaluated the accumulation preferences and capacities, the distribution and processes of biomineralization of metals (Fe, Cu, Zn, Mn, Mg, Ca) in the first stages of growth of EA and LEA oleanders by means of inductively coupled plasma-mass spectrometry, scanning electron microscopy, and energy dispersive X-ray analyzer analysis. Seeds from both environments were grown and treated with a self-made solution simulating the most extreme red waters from the Río Tinto. LEA plants drastically reduces the metal uptake at the beginning, but later reactivates the uptake reaching concentration values in the same range as the EA plants. The results showed high Mn, Zn and Mg concentrations, accumulation of Fe and Cu in plants from both environments, differing from the metal concentrations of field-grown oleanders. Iron bioformations with traces of other metals were present inside and over epidermal cells and inside vascular cells of stems and roots. They were absent of leaves. The accumulation properties of N. oleander in its early stages of development make it a species to take in consideration in phytoremediation processes but optimized conditions are needed to ensure enough biomass production. PMID:23892697

Franco, Alejandro; Rufo, Lourdes; Zuluaga, Javier; de la Fuente, Vicenta

2013-10-01

44

Development and structure of eukaryotic biofilms in an extreme acidic environment, rio tinto (SW, Spain).  

PubMed

An in situ colonization assay was performed to study the early stages of biofilm formation in Rio Tinto (SW, Spain), an extremely acidic environment (pH ca. 2). Eukaryotic assemblages were monitored at monthly intervals for 1 year. Diversity, colonization rates, and seasonal variations were analyzed. Structural features of naturally grown biofilms were explored by light and scanning electron microscopy in backscattered electron mode. A total of 14 taxa were recognized as constituents of the eukaryotic assemblages. The eukaryotic communities were dissimilar at the different sampling sites. The lowest diversity was found at the most extreme locations, in terms of pH and heavy metal concentrations. The biofilms were mainly formed by species from the genera Dunaliella and Cyanidium. Two genera of filamentous algae, Zygnemopsis and Klebsormidium, were principally responsible for the variability in the cell number throughout the year. These species appear in June to decrease almost completely between October and November. In contrast, the number of heterotrophic flagellates and ciliates remained constant throughout the year. The microcolonization sequence showed an initial accumulation of amorphous particles composed of bacteria and inorganic grains of minerals. By the end of the second month, the organic matrix was also populated by fungi, bacteria, and a few eukaryotic heterotrophs such as amoebae and small flagellates. Diatoms only showed significant colonization in regions where mycelial matrices were first established. Flagellated green algae such as Dunaliella or Chlamydomonas as well as Euglena were also present at the very beginning of the biofilm development, although in low numbers (<100 cells cm(-2)). After the flagellated cells, sessile species of algae such Chlorella or Cyanidium appeared. Filamentous algae were the last species to colonize the biofilms. Most of the naturally grown biofilms were found to be structures composed of different species organized in different layers separated, probably by extracellular polymeric substances, although more analysis should be done in this regard. The possible implications of the biofilm structure in the adaptation to this extreme habitat are discussed. PMID:17268880

Aguilera, Angeles; Souza-Egipsy, Virginia; Gómez, Felipe; Amils, Ricardo

2007-02-01

45

Prokaryotic community composition and ecology of floating macroscopic filaments from an extreme acidic environment, Río Tinto (SW, Spain).  

PubMed

The prokaryotic diversity of macroscopic filaments located at the water surface in an extreme acidic environment, Río Tinto (SW, Spain), has been analysed through denaturing gradient gel electrophoresis (DGGE), cloning of 16S rRNA genes and fluorescence in situ hybridization (FISH). The dominant species present in the macrofilaments were Acidithiobacillus ferrooxidans, Leptospirillum ferrooxidans and Acidiphilium spp., which represented the three main bacterial genera found in the water column of the river. However, our results also showed the presence of other microorganisms not previously detected in the Río Tinto. Within the Gammaproteobacteria class, sequences closely related to the iron-oxidizing bacteria WJ2 and DSM 2392 were found, as well as sequences related to the non-acidophilic genera Aeromonas and Acinetobacter. In addition, two other new phylotypes related to Gram-positive species from the genera Desulfosporosinus, Clostridium and Mycobacterium were identified. The presence of these anaerobic microorganisms strongly suggests that the filaments could originate in the deeper parts of the river as a typical acid streamer attached to the rocks or the sediments and be pulled up towards the surface when they reach certain buoyancy. PMID:17950555

García-Moyano, A; González-Toril, E; Aguilera, A; Amils, R

2007-12-01

46

ESTABELECENDO PONTES ENTRE O OCIDENTE E O ORIENTE: UM CONTRIBUTO DA PERSPECTIVA BUDISTA NA EDUCAÇÃO PARA A SUSTENTABILIDADE  

Microsoft Academic Search

Dialogue among cultures is a main characteristic on the knowledge construction in the 21st century societies. In this document, following a tradition started around thirty years ago, we try a conversation between western science and eastern Mahayana Buddhist school. The goal of this conversation is to find what contribute this philosophical tradition may give to the development of sustained societies

Orlando Figueiredo; Escola Secundária de Peniche

2006-01-01

47

Scientific results and lessons learned from an integrated crewed Mars exploration simulation at the Rio Tinto Mars analogue site  

NASA Astrophysics Data System (ADS)

Between 15 and 25 April 2011 in the framework of the PolAres programme of the Austrian Space Forum, a five-day field test of the Aouda.X spacesuit simulator was conducted at the Rio Tinto Mars-analogue site in southern Spain. The field crew was supported by a full-scale Mission Control Center (MCC) in Innsbruck, Austria. The field telemetry data were relayed to the MCC, enabling a Remote Science Support (RSS) team to study field data in near-real-time and adjust the flight planning in a flexible manner. We report on the experiences in the field of robotics, geophysics (Ground Penetrating Radar) and geology as well as life sciences in a simulated spaceflight operational environment. Extravehicular Activity (EVA) maps had been prepared using Google Earth and aerial images. The Rio Tinto mining area offers an excellent location for Mars analogue simulations. It is recognised as a terrestrial Mars analogue site because of the presence of jarosite and related sulphates, which have been identified by the NASA Mars Exploration Rover "Opportunity" in the El Capitan region of Meridiani Planum on Mars. The acidic, high ferric-sulphate content water of Rio Tinto is also considered as a possible analogue in astrobiology regarding the analysis of ferric sulphate related biochemical pathways and produced biomarkers. During our Mars simulation, 18 different types of soil and rock samples were collected by the spacesuit tester. The Raman results confirm the presence of minerals expected, such as jarosite, different Fe oxides and oxi-hydroxides, pyrite and complex Mg and Ca sulphates. Eight science experiments were conducted in the field. In this contribution first we list the important findings during the management and realisation of tests, and also a first summary of the scientific results. Based on these experiences suggestions for future analogue work are also summarised. We finish with recommendations for future field missions, including the preparation of the experiments, communication and data transfer - as an aid to the planning of future simulations.

Orgel, Csilla; Kereszturi, Ákos; Váczi, Tamás; Groemer, Gernot; Sattler, Birgit

2014-02-01

48

A Search for Life in the Subsurface At Rio Tinto Spain, An Analog To Searching For Life On Mars.  

NASA Astrophysics Data System (ADS)

Most familiar life forms on Earth live in the surface biosphere where liquid water, sunlight, and the essential chemical elements for life are abundant. However, such environments are not found on Mars or anywhere else in the solar system. On Mars, the surface environmental conditions of pressure and temperature prevent formation of liquid water. Furthermore, conditions at the Martian surface are unfavorable to life due to intense ultraviolet radiation and strong oxidizing compounds that destroy organic compounds. However, subsurface liquid water on Mars has been predicted on theoretical grounds. The recent discovery of near surface ground ice by the Mars Odyssey mission, and the abundant evidence for recent Gully features observed by the Mars Global Surveyor mission strengthen the case for subsurface liquid water on Mars. Thus, the strategy for searching for life on Mars points to drilling to the depth of liquid water, bringing samples to the surface and analyzing them with instrumentation to detect in situ organisms and biomarker compounds. The MARTE (Mars Astrobiology Research and Technology Experiment) project is a field experiment focused on searching for a hypothesized subsurface anaerobic chemoautotrophic biosphere in the region of the Rio Tinto, a river in southwestern Spain while also demonstrating technology relevant to searching for a subsurface biosphere on Mars. The Tinto river is located in the Iberian Pyrite belt, one of the largest deposits of sulfide minerals in the world. The surface (river) system is an acidic extreme environment produced and maintained by microbes that metabolize sulfide minerals and produce sulfuric acid as a byproduct. Evidence suggests that the river is a surface manifestation of an underground biochemical reactor. Organisms found in the river are capable of chemoautotrophic metabolism using sulfide and ferric iron mineral substrates, suggesting these organisms could thrive in groundwater which is the source of the Rio Tinto. The MARTE project will simulate the search for subsurface life on Mars using a drilling system developed for future Mars flight to accomplish subsurface access. Augmenting the drill are robotic systems for extracting the cores from the drill head and performing analysis using a suite of instruments to understand the composition, mineralogy, presence of organics, and to search for life signatures in subsurface samples. A robotic bore-hole inspection system will characterize borehole properties in situ. A Mars drilling mission simulation including remote operation of the drilling, sample handling, and instruments and interpretation of results by a remote science team will be performed. This simulated mission will be augmented by manual methods of drilling, sample handling, and sample analysis to fully document the subsurface, prevent surface microbial contamination, identify subsurface biota, and compare what can be learned with robotically-operated instruments. The first drilling campaign in the MARTE project takes place in September 2003 and is focused on characterizing the microbiology of the subsurface at Rio Tinto using conventional drilling, sample handling and laboratory analysis techniques. Lessons learned from this "ground truth" drilling campaign will guide the development of robotic systems and instruments needed for searching for life underground on Mars.

Stoker, C. R.

2003-12-01

49

Río Tinto sedimentary mineral assemblages: A terrestrial perspective that suggests some formation pathways of phyllosilicates on Mars  

NASA Astrophysics Data System (ADS)

The presence of extensive phyllosilicate deposits from the early Noachian of Mars are often interpreted as having formed from neutral to subalkaline solutions. In this paper we examine the Río Tinto fluvial basin, an early Mars analog, that hosts clay production and sedimentation along the entire course of the river. At Río Tinto, phyllosilicate minerals including clays and micas are sourced by volcanosedimentary bedrock of rhyolitic and andesitic composition affected by Carboniferous hydrothermal alteration. Pleistocene to modern acidic weathering of those materials chemically altered the volcanic and sedimentary materials to K/Na-clay-(montmorillonite/smectites)-kaolinite assemblages in paleosoils and fractures while physical weathering degrades phyllosilicates more resistant to acidic attack. During the wet season, phyllosilicates are eroded, transported and deposited from both acidic headwaters and neutral tributaries. During the dry season, sulfates and nanophase oxyhydroxides co-precipitate. Late summer storms that cause fast flooding events mix illite, quartz, feldspars, iron oxides and other minerals in fluvial deposits where these minerals are stabilized and aggrade until the following wet season. As a result, chemical precipitates, primary phyllosilicates and secondary clays form mineral admixtures that explain the compositional diversity of the fluvial deposits. These deposits reveal the persistence of smectites, whose occurrence is explained given that the reaction kinetics under acidic conditions of degradation is lowered by seasonal discharges of the river. The longevity of phyllosilicate minerals within fluvial deposits depends on climatic and geochemical conditions and processes which are in turn are correlated to temperature, persistence of water, hydrological cycling, hydrogeochemistry and composition of the source materials in the basement. These parameters are universal and have to be characterized in order to understand the distribution of mineral composition on any planetary surface, including Mars.

Fernández-Remolar, D. C.; Prieto-Ballesteros, O.; Gómez-Ortíz, D.; Fernández-Sampedro, M.; Sarrazin, P.; Gailhanou, M.; Amils, R.

2011-01-01

50

Mars Analog Research and Technology Experiment (MARTE): A Simulated Mars Drilling Mission to Search for Subsurface Life at the Rio Tinto, Spain  

NASA Technical Reports Server (NTRS)

The MARTE (Mars Astrobiology Research and Technology Experiment) project was selected by the new NASA ASTEP program, which supports field experiments having an equal emphasis on Astrobiology science and technology development relevant to future Astrobiology missions. MARTE will search for a hypothesized subsurface anaerobic chemoautotrophic biosphere in the region of the Tinto River in southwestern Spain while also demonstrating technology needed to search for a subsurface biosphere on Mars. The experiment is informed by the strategy for searching for life on Mars.

Stoker, Carol; Lemke, Larry; Mandell, Humboldt; McKay, David; George, Jeffrey; Gomez-Alvera, Javier; Amils, Ricardo; Stevens, Todd; Miller, David

2003-01-01

51

RIO Tinto Faulted Volcanosedimentary Deposits as Analog Habitats for Extant Subsurface Biospheres on Mars: A Synthesis of the MARTE Drilling Project Geobiology Results  

NASA Technical Reports Server (NTRS)

Geochemistry and mineralogy on Mars surface characterized by the MER Opportunity Rover suggest that early Mars hosted acidic environments in the Meridiani Planum region [1, 2]. Such extreme paleoenvironments have been suggested to be a regional expression of the global Mars geological cycle that induced acidic conditions by sulfur complexation and iron buffering of aqueous solutions [3]. Under these assumptions, underground reservoirs of acidic brines and, thereby, putative acidic cryptobiospheres, may be expected. The MARTE project [4, 5] has performed a drilling campaign to search for acidic and anaerobic biospheres in R o Tinto basement [6] that may be analogs of these hypothetical communities occurring in cryptic habitats of Mars. This Rio Tinto geological region is characterized by the occurrence of huge metallic deposits of iron sulfides [7]. Late intensive diagenesis of rocks driven by a compressive regimen [8] largely reduced the porosity of rocks and induced a cortical thickening through thrusting and inverse faulting and folding. Such structures play an essential role in transporting and storing water underground as any other aquifers do in the Earth. Once the underground water reservoirs of the Ro Tinto basement contact the hydrothermal pyrite deposits, acidic brines are produced by the release of sulfates and iron through the oxidation of sulfides [9].

Fernandez-Remolar, D. C.; Prieto-Ballesteros, O.; Rodriquez, N.; Davila, F.; Stevens, T.; Amils, R.; Gomez-Elvira, J.; Stoker, C.

2005-01-01

52

Mineralogical In-situ Investigation of Acid-Sulfate Samples from the Rio Tinto River, Spain, with a Portable XRD/XRF Instrument  

NASA Technical Reports Server (NTRS)

A field campaign was organized in September 2006 by Centro de Astobiologica (Spain) and Washington University (St Louis, USA) for the geological study of the Rio Tinto river bed sediments using a suite of in-situ instruments comprising an ASD reflectance spectrometer, an emission spectrometer, panoramic and close-up color imaging cameras, a life detection system and NASA's CheMin 4 XRD/XRF prototype. The primary objectives of the field campaign were to study the geology of the site and test the potential of the instrument suite in an astrobiological investigation context for future Mars surface robotic missions. The results of the overall campaign will be presented elsewhere. This paper focuses on the results of the XRD/XRF instrument deployment. The specific objectives of the CheMin 4 prototype in Rio Tinto were to 1) characterize the mineralogy of efflorescent salts in their native environments; 2) analyze the mineralogy of salts and oxides from the modern environment to terraces formed earlier as part of the Rio Tinto evaporative system; and 3) map the transition from hematite-dominated terraces to the mixed goethite/salt-bearing terraces where biosignatures are best preserved.

Sarrazin, P.; Ming, D. W.; Morris, R. V.; Fernandez-Remolar, D.; Amils, R.; Arvidson, R. E.; Blake, D.; Bish, D. L.

2007-01-01

53

Classification of modern and old Río Tinto sedimentary deposits through the biomolecular record using a life marker biochip: implications for detecting life on Mars.  

PubMed

The particular mineralogy formed in the acidic conditions of the Río Tinto has proven to be a first-order analogue for the acid-sulfate aqueous environments of Mars. Therefore, studies about the formation and preservation of biosignatures in the Río Tinto will provide insights into equivalent processes on Mars. We characterized the biomolecular patterns recorded in samples of modern and old fluvial sediments along a segment of the river by means of an antibody microarray containing more than 200 antibodies (LDCHIP200, for Life Detector Chip) against whole microorganisms, universal biomolecules, or environmental extracts. Samples containing 0.3-0.5?g of solid material were automatically analyzed in situ by the Signs Of LIfe Detector instrument (SOLID2), and the results were corroborated by extensive analysis in the laboratory. Positive antigen-antibody reactions indicated the presence of microbial strains or high-molecular-weight biopolymers that originated from them. The LDCHIP200 results were quantified and subjected to a multivariate analysis for immunoprofiling. We associated similar immunopatterns, and biomolecular markers, to samples with similar sedimentary age. Phyllosilicate-rich samples from modern fluvial sediments gave strong positive reactions with antibodies against bacteria of the genus Acidithiobacillus and against biochemical extracts from Río Tinto sediments and biofilms. These samples contained high amounts of sugars (mostly polysaccharides) with monosaccharides like glucose, rhamnose, fucose, and so on. By contrast, the older deposits, which are a mix of clastic sands and evaporites, showed only a few positives with LDCHIP200, consistent with lower protein and sugar content. We conclude that LDCHIP200 results can establish a correlation between microenvironments, diagenetic stages, and age with the biomarker profile associated with a sample. Our results would help in the search for putative martian biomarkers in acidic deposits with similar diagenetic maturity. Our LDCHIP200 and SOLID-like instruments may be excellent tools for the search for molecular biomarkers on Mars or other planets. PMID:21294642

Parro, Victor; Fernández-Remolar, David; Rodríguez-Manfredi, José A; Cruz-Gil, Patricia; Rivas, Luis A; Ruiz-Bermejo, Marta; Moreno-Paz, Mercedes; García-Villadangos, Miriam; Gómez-Ortiz, David; Blanco-López, Yolanda; Menor-Salván, César; Prieto-Ballesteros, Olga; Gómez-Elvira, Javier

2011-01-01

54

Eukaryotic Community Distribution and Its Relationship to Water Physicochemical Parameters in an Extreme Acidic Environment, R?o Tinto (Southwestern Spain)†  

PubMed Central

The correlation between water physicochemical parameters and eukaryotic benthic composition was examined in Río Tinto. Principal component analysis showed a high inverse relationship between pH and most of the heavy metals analyzed as well as Dunaliella sp., while Chlamydomonas sp. abundance was positively related. Zn, Cu, and Ni clustered together and showed a strong inverse correlation with the diversity coefficient and most of the species analyzed. These eukaryotic communities seem to be more influenced by the presence of heavy metals than by the pH.

Aguilera, Angeles; Manrubia, Susanna C.; Gomez, Felipe; Rodriguez, Nuria; Amils, Ricardo

2006-01-01

55

Science Results from a Mars Drilling Simulation (Río Tinto, Spain) and Ground Truth for Remote Science Observations  

NASA Astrophysics Data System (ADS)

Science results from a field-simulated lander payload and post-mission laboratory investigations provided "ground truth" to interpret remote science observations made as part of the 2005 Mars Astrobiology Research and Technology Experiment (MARTE) drilling mission simulation. The experiment was successful in detecting evidence for life, habitability, and preservation potential of organics in a relevant astrobiological analogue of Mars. Science results. Borehole 7 was drilled near the Río Tinto headwaters at Peña de Hierro (Spain) in the upper oxidized remnant of an acid rock drainage system. Analysis of 29 cores (215 cm of core was recovered from 606 cm penetrated depth) revealed a matrix of goethite- (42-94%) and hematite-rich (47-87%) rocks with pockets of phyllosilicates (47-74%) and fine- to coarse-grained loose material. Post-mission X-ray diffraction (XRD) analysis confirmed the range of hematite:goethite mixtures that were visually recognizable (˜1:1, ˜1:2, and ˜1:3 mixtures displayed a yellowish-red color whereas 3:1 mixtures displayed a dark reddish-brown color). Organic carbon was poorly preserved in hematite/goethite-rich materials (Corg <0.05 wt %) beneath the biologically active organic-rich soil horizon (Corg ˜3-11 wt %) in contrast to the phyllosilicate-rich zones (Corg ˜0.23 wt %). Ground truth vs. remote science analysis. Laboratory-based analytical results were compared to the analyses obtained by a Remote Science Team (RST) using a blind protocol. Ferric iron phases, lithostratigraphy, and inferred geologic history were correctly identified by the RST with the exception of phyllosilicate-rich materials that were misinterpreted as weathered igneous rock. Adenosine 5?-triphosphate (ATP) luminometry, a tool available to the RST, revealed ATP amounts above background noise, i.e., 278-876 Relative Luminosity Units (RLUs) in only 6 cores, whereas organic carbon was detected in all cores. Our manned vs. remote observations based on automated acquisitions during the project provide insights for the preparation of future astrobiology-driven Mars missions.

Bonaccorsi, Rosalba; Stoker, Carol R.

2008-10-01

56

A description of how metal pollution occurs in the Tinto-Odiel rias (Huelva-Spain) through the application of cluster analysis.  

PubMed

In the last few decades, the study of space-time distribution and variations of heavy metals in estuaries has been extensively studied as an environmental indicator. In the case described here, the combination of acid water from mines, industrial effluents and sea water plays a determining role in the evolutionary process of the chemical makeup of the water in the estuary of the Tinto and Odiel Rivers, located in the southwest of the Iberian Peninsula. Based on the statistical treatment of the data from the analysis of the water samples from this system, which has been affected by processes of industrial and mining pollution, the 16 variables analyzed can be grouped into two large families. Each family presents high, positive Pearson r values that suggest common origins (fluvial or sea) for the pollutants present in the water analyzed and allow their subsequent contrast through cluster analysis. PMID:12705921

Grande, J A; Borrego, J; Morales, J A; de la Torre, M L

2003-04-01

57

Contribution of mine wastes to atmospheric metal deposition in the surrounding area of an abandoned heavily polluted mining district (Rio Tinto mines, Spain).  

PubMed

The present study seeks to estimate the impact of abandoned mine wastes on the levels and chemical profile of total atmospheric deposition in one of the oldest and largest mining districts in Europe (Rio Tinto mines, Iberian Pyrite Belt), on the basis of a complete geochemical characterization of particulate matter samples periodically collected in five sampling stations located around the mining district between March 2009 and February 2011. The annual levels of total bulk deposition (soluble and insoluble fractions) registered in the Rio Tinto Mining District ranged between 18 and 43 g/m(2) depending on the distance from the sampling station with regard to the mine waste deposits. As a general pattern in the area, high mass levels of Zn and Cu were deposited in a range of 9-62 mg/m(2) not only in the insoluble but also in the soluble fraction. Other potentially toxic trace elements such as As, Sb, Ba, Pb, Sn and Bi showed greater deposition fluxes in the locations closest to the mine waste deposits. A principal component analysis with a Multilinear Regression Analysis certifies the presence of two common sources in the mining area: 1) a mineral factor composed mainly of elements derived from silicate minerals (Al, Ca, Sr, Ti, Li, Mg, Mn, K, Na and Fe), mixed with other anthropogenic species (NH4(+), SO4(2-), NO3(-)) within the village closest to the mine; and 2) a marine factor composed of Na, Cl, Mg, SO4(2-) and Sr. In addition, a mine waste factor made up of toxic elements (Cu, Zn, Ga, As, Sb, Ba, Pb, Sn, Cd and Bi) has been recognized in the sampling sites exposed to dust-bearing winds downwind of the mining area, suggesting that mine wastes are a relevant source of heavy-mineral particles with potentially adverse environmental effects to surrounding soils, plants and humans. PMID:23454697

Castillo, Sonia; de la Rosa, Jesús D; Sánchez de la Campa, Ana M; González-Castanedo, Yolanda; Fernández-Caliani, Juan C; Gonzalez, Isabel; Romero, Antonio

2013-04-01

58

Some Ecological Mechanisms to Generate Habitability in Planetary Subsurface Areas by Chemolithotrophic Communities: The Ro Tinto Subsurface Ecosystem as a Model System  

NASA Astrophysics Data System (ADS)

Chemolithotrophic communities that colonize subsurface habitats have great relevance for the astrobiological exploration of our Solar System. We hypothesize that the chemical and thermal stabilization of an environment through microbial activity could make a given planetary region habitable. The MARTE project ground-truth drilling campaigns that sampled cryptic subsurface microbial communities in the basement of the Ro Tinto headwaters have shown that acidic surficial habitats are the result of the microbial oxidation of pyritic ores. The oxidation process is exothermic and releases heat under both aerobic and anaerobic conditions. These microbial communities can maintain the subsurface habitat temperature through storage heat if the subsurface temperature does not exceed their maximum growth temperature. In the acidic solutions of the Ro Tinto, ferric iron acts as an effective buffer for controlling water pH. Under anaerobic conditions, ferric iron is the oxidant used by microbes to decompose pyrite through the production of sulfate, ferrous iron, and protons. The integration between the physical and chemical processes mediated by microorganisms with those driven by the local geology and hydrology have led us to hypothesize that thermal and chemical regulation mechanisms exist in this environment and that these homeostatic mechanisms could play an essential role in creating habitable areas for other types of microorganisms. Therefore, searching for the physicochemical expression of extinct and extant homeostatic mechanisms through physical and chemical anomalies in the Mars crust (i.e., local thermal gradient or high concentration of unusual products such as ferric sulfates precipitated out from acidic solutions produced by hypothetical microbial communities) could be a first step in the search for biological traces of a putative extant or extinct Mars biosphere.

Fernández-Remolar, David C.; Gómez, Felipe; Prieto-Ballesteros, Olga; Schelble, Rachel T.; Rodríguez, Nuria; Amiols, Ricardo

2008-02-01

59

Energia solar fotovoltaica: Contributo para um roadmapping do seu desenvolvimento tecnológico [Fotovoltaic solar energy: a contribute to a technological development roadmapping  

Microsoft Academic Search

The main goal for this report is to alert for the need of a continuous investment in policies that should be developed worldwide, with respect to research and development (R&D), at all levels, in photovoltaic energy. The R&D in this area leads to a strong and possible solution to the actual environmental problems. Such problems are based on the climate

Hugo Gil Silva; Marcos Afonso

2009-01-01

60

Organic and Inorganic Carbon in the Rio Tinto (Spain) Deep Subsurface System: a Possible Model for Subsurface Carbon and Lithoautotrophs on Mars.  

NASA Astrophysics Data System (ADS)

The subsurface is the key environment for searching for life on planets lacking surface life. Subsurface ecosystems are of great relevance to astrobiology including the search for past/present life on Mars. Conditions on the Martian surface do not support biological activity but the subsurface might preserve organics and host subsurface life [1]. A key requirement for the analysis of subsurface samples on Mars is the ability to characterize organic vs. inorganic carbon pools. This information is needed to determine if the sample contains organic material of biological origin and/ or to establish if pools of inorganic carbon can support subsurface biospheres. The Mars Analog Rio Tinto Experiment (MARTE) performed deep drilling of cores i.e., down to 165-m depth, in a volcanically-hosted-massive-sulfide deposit at Rio Tinto, Spain, which is considered an important analog of the Sinus Meridiani site on Mars. Results from MARTE suggest the existence of a relatively complex subsurface life including aerobic and anaerobic chemoautotrophs, and strict anaerobic methanogens sustained by Fe and S minerals in anoxic conditions, which is an ideal model analog for a deep subsurface Martian environment. We report here on the distribution of organic (C-org: 0.01-0.3Wt% and inorganic carbon (IC = 0.01-7.0 Wt%) in a subsurface rock system including weathered/oxidized i.e., gossan, and unaltered pyrite stockwork. Cores were analyzed from 3 boreholes (BH-4, BH-7, and BH-8) that penetrated down to a depth of ~165 m into massive sulfide. Nearsurface phyllosilicate rich-pockets contain the highest amounts of organics (0.3Wt%) [2], while the deeper rocks contain the highest amount of carbonates. Assessing the amount of C pools available throughout the RT subsurface brings key insight on the type of trophic system sustaining its microbial ecosystem (i.e., heterotrophs vs. autotrophs) and the biogeochemical relationships that characterize a new type of subsurface biosphere at RT. This potentially novel biosphere on Earth could be used as a model to test for extant and extinct life on Mars. Furthermore, having found carbonates in an hyperacidic system (pH ~2.3) brings new insights on the possible occurrence of deep carbonates deposits under low-pH condition on Mars. [1] Boston, P.J., et al., 1992. Icarus 95,300-308; Bonaccorsi, Stoker and Sutter, 2007 Accepted with review in Astrobiology.

Bonaccorsi, R.; Stoker, C. R.; MARTE Science Team

2007-12-01

61

Visible-Near Infrared Point Spectrometry of Drill Core Samples from Río Tinto, Spain: Results from the 2005 Mars Astrobiology Research and Technology Experiment (MARTE) Drilling Exercise  

NASA Astrophysics Data System (ADS)

Sampling of subsurface rock may be required to detect evidence of past biological activity on Mars. The Mars Astrobiology Research and Technology Experiment (MARTE) utilized the Río Tinto region, Spain, as a Mars analog site to test dry drilling technologies specific to Mars that retrieve subsurface rock for biological analysis. This work examines the usefulness of visible-near infrared (VNIR) (450-1000 nm) point spectrometry to characterize ferric iron minerals in core material retrieved during a simulated Mars drilling mission. VNIR spectrometry can indicate the presence of aqueously precipitated ferric iron minerals and, thus, determine whether biological analysis of retrieved rock is warranted. Core spectra obtained during the mission with T1 (893-897 nm) and T2 (644-652 nm) features indicate goethite-dominated samples, while relatively lower wavelength T1 (832-880 nm) features indicate hematite. Hematite/goethite molar ratios varied from 0 to 1.4, and within the 880-898 nm range, T1 features were used to estimate hematite/goethite molar ratios. Post-mission X-ray analysis detected phyllosilicates, which indicates that examining beyond the VNIR (e.g., shortwave infrared, 1000-2500 nm) will enhance the detection of other minerals formed by aqueous processes. Despite the limited spectral range of VNIR point spectrometry utilized in the MARTE Mars drilling simulation project, ferric iron minerals could be identified in retrieved core material, and their distribution served to direct core subsampling for biological analysis.

Sutter, Brad; Brown, Adrian J.; Stoker, Carol R.

2008-10-01

62

The Subsurface Geology of Río Tinto: Material Examined During a Simulated Mars Drilling Mission for the Mars Astrobiology Research and Technology Experiment (MARTE)  

NASA Astrophysics Data System (ADS)

The 2005 Mars Astrobiology Research and Technology Experiment (MARTE) project conducted a simulated 1-month Mars drilling mission in the Río Tinto district, Spain. Dry robotic drilling, core sampling, and biological and geological analytical technologies were collectively tested for the first time for potential use on Mars. Drilling and subsurface sampling and analytical technologies are being explored for Mars because the subsurface is the most likely place to find life on Mars. The objectives of this work are to describe drilling, sampling, and analytical procedures; present the geological analysis of core and borehole material; and examine lessons learned from the drilling simulation. Drilling occurred at an undis closed location, causing the science team to rely only on mission data for geological and biological interpretations. Core and borehole imaging was used for micromorphological analysis of rock, targeting rock for biological analysis, and making decisions regarding the next day's drilling operations. Drilling reached 606 cm depth into poorly consolidated gossan that allowed only 35% of core recovery and contributed to borehole wall failure during drilling. Core material containing any indication of biology was sampled and analyzed in more detail for its confirmation. Despite the poorly consolidated nature of the subsurface gossan, dry drilling was able to retrieve useful core material for geological and biological analysis. Lessons learned from this drilling simulation can guide the development of dry drilling and subsurface geological and biological analytical technologies for future Mars drilling missions.

Prieto-Ballesteros, Olga; Martínez-Frías, Jesús; Schutt, John; Sutter, Brad; Heldmann, Jennifer L.; Bell Johnson, Mary Sue; Battler, Melissa; Cannon, Howard; Gómez-Elvira, Javier; Stoker, Carol R.

2008-10-01

63

The 2005 MARTE Robotic Drilling Experiment in Río Tinto, Spain: Objectives, Approach, and Results of a Simulated Mission to Search for Life in the Martian Subsurface  

NASA Astrophysics Data System (ADS)

The Mars Astrobiology Research and Technology Experiment (MARTE) simulated a robotic drilling mission to search for subsurface life on Mars. The drill site was on Peña de Hierro near the headwaters of the Río Tinto river (southwest Spain), on a deposit that includes massive sulfides and their gossanized remains that resemble some iron and sulfur minerals found on Mars. The mission used a fluidless, 10-axis, autonomous coring drill mounted on a simulated lander. Cores were faced; then instruments collected color wide-angle context images, color microscopic images, visible near infrared point spectra, and (lower resolution) visible-near infrared hyperspectral images. Cores were then stored for further processing or ejected. A borehole inspection system collected panoramic imaging and Raman spectra of borehole walls. Life detection was performed on full cores with an adenosine triphosphate luciferin-luciferase bioluminescence assay and on crushed core sections with SOLID2, an antibody array-based instrument. Two remotely located science teams analyzed the remote sensing data and chose subsample locations. In 30 days of operation, the drill penetrated to 6 m and collected 21 cores. Biosignatures were detected in 12 of 15 samples analyzed by SOLID2. Science teams correctly interpreted the nature of the deposits drilled as compared to the ground truth. This experiment shows that drilling to search for subsurface life on Mars is technically feasible and scientifically rewarding.

Stoker, Carol R.; Cannon, Howard N.; Dunagan, Stephen E.; Lemke, Lawrence G.; Glass, Brian J.; Miller, David; Gomez-Elvira, Javier; Davis, Kiel; Zavaleta, Jhony; Winterholler, Alois; Roman, Matt; Rodriguez-Manfredi, Jose Antonio; Bonaccorsi, Rosalba; Bell, Mary Sue; Brown, Adrian; Battler, Melissa; Chen, Bin; Cooper, George; Davidson, Mark; Fernández-Remolar, David; Gonzales-Pastor, Eduardo; Heldmann, Jennifer L.; Martínez-Frías, Jesus; Parro, Victor; Prieto-Ballesteros, Olga; Sutter, Brad; Schuerger, Andrew C.; Schutt, John; Rull, Fernando

2008-10-01

64

Influence of the very polluted inputs of the Tinto-Odiel system on the adjacent littoral sediments of southwestern Spain: a statistical approach.  

PubMed

A spatial and temporal analysis (period 1990-2003) of 15 sampling points distributed along the southwestern Spanish coast permits to delimitate the influence area of the extremely polluted discharges coming from the Tinto-Odiel system in the bottom sediments of the adjacent littoral area. As, Cu, Pb and Zn are the main heavy metals transported by the freshwater runoffs toward the shallow shelf and present very high negative (r < -0.7) and significant (p < 0.001) correlations with the distance to the estuarine mouth. The statistical analysis (index of geoaccumulation, Pearson correlation matrix, cluster analysis) of their concentrations in the littoral sediments located between the Guadiana and Guadalquivir mouths delimitates three zones: (a) Zone 1 (from the estuarine mouth to 6 km to the east), characterized by moderate to strongly polluted bottom sediments and main responsible of the mean annual variations of the former heavy metals in the area studied; (b) Zone 2 (from 21.2 km to the west to 29 km to the east), characterized by moderate pollution levels; and (c) Zone 3, located near the Guadiana and Guadalquivir mouths, with very low As-Cu-Pb contents and unpolluted to moderately levels of Zn due to urban sewages or the presence of local low mobility areas for this element. PMID:16122777

Sainz, A; Ruiz, F

2006-03-01

65

Chemical and Isotopic Characterization of Waters in Rio Tinto, Spain, Shows Possible Origin of the Blueberry Haematite Nodules in Meridiani Planum, Mars  

NASA Astrophysics Data System (ADS)

Meridiani Planum sediments formed in an acid environment and include jarosite and other evaporitic sulfate minerals. Nodular spheroidal concretions appear to have grown in situ and are predominantly hematite. The source of the Rio Tinto, S. Spain, drains an area of extensive sulfide mineralization and is dominated by acid mine drainage processes. The system is not a Mars analog but potentially similar processes of sulfide oxidation produce sulfate rich waters which feed into the river and precipitate a large range of evaporitic sulfates including jarosite. Iron oxide minerals associated with the evaporites are either dispersed or bedded but not nodular. The water compositions appear to be mixtures of a few discreet end-members: the two most significant occur in undiluted form as inputs to the river and are relevant to many such systems. They both have all sulfur totally oxidized as sulfate. The first is a bright red water, pH ~1.5, Fe/S 0.5 and 23 g/L iron which is greater than 95% Fe3+. Its sulfate oxygen isotope composition is +2‰SMOW and about +7‰, relative to the water O isotope composition. These data indicate pyrite oxidation by Fe3+ with O in sulfate coming mainly from water. The second end-member is a pale green water, pH ~0.7, Fe/S 0.7, 50 g/L iron present mainly as Fe2+ and O isotope composition of sulfate about +6‰SMOW , about +12.5‰ relative to the water O value. Oxygen in sulfate comes mainly from atmospheric oxygen resulting from pyrite oxidation by molecular oxygen dissolved in water. Although the Rio Tinto system reactions probably are microbiologically mediated (relevant genera have been identified there) similar processes could occur abiotically but more slowly. Meridiani Planum sediments and nodules can be described by a plausible set of similar end-member processes. The primary source of sulfate is oxidation of sulfides present in basalt (pyrite, FeS2 or pyrrhotite, FeS) and weathering would have produced oxidized sulfate rich solutions at low pH. Ground water migration could produce evaporitic ponds where various bedded sulfate mineral sediments could form. The intergranular pore-spaces would be water filled. Most terrestrial spheroidal nodular concretions form by radial diffusion in pore-water of a chemical component of a very different oxidation state from that of the surrounding water. A nodular concretion is most usually formed by the reaction of the diffusive component with others in the pore-water. There are two main possible reaction sets for formation of the Blueberries that are consistent with all current data. 1. Local concentrations of organic matter (pre-biotic or biotic) formed reduction spots in which a small amount of Fe3+ either in solution or from evaporite mineral salts, was reduced to Fe2+ and then diffused radially to form an iron oxide nodule by reaction with inwardly diffusing dissolved oxygen. 2. Similar local concentrations of organic matter could also have engendered sulfate reduction and consequent outward diffusion of dissolved sulfide reacted with iron in solution to produce an iron sulfide nodule, subsequently oxidized in situ to hematite (maybe via goethite). Our current work is successfully identifying chemical and stable isotopic characteristics for both microbial and abiotic modes of all relevant reactions.

Coleman, M. L.; Hubbard, C. G.; Mielke, R. E.; Black, S.

2005-12-01

66

Quantification of Tinto River Sediment Microbial Communities: Importance of Sulfate-Reducing Bacteria and Their Role in Attenuating Acid Mine Drainage  

PubMed Central

Tinto River (Huelva, Spain) is a natural acidic rock drainage (ARD) environment produced by the bio-oxidation of metallic sulfides from the Iberian Pyritic Belt. This study quantified the abundance of diverse microbial populations inhabiting ARD-related sediments from two physicochemically contrasting sampling sites (SN and JL dams). Depth profiles of total cell numbers differed greatly between the two sites yet were consistent in decreasing sharply at greater depths. Although catalyzed reporter deposition fluorescence in situ hybridization with domain-specific probes showed that Bacteria (>98%) dominated over Archaea (<2%) at both sites, important differences were detected at the class and genus levels, reflecting differences in pH, redox potential, and heavy metal concentrations. At SN, where the pH and redox potential are similar to that of the water column (pH 2.5 and +400 mV), the most abundant organisms were identified as iron-reducing bacteria: Acidithiobacillus spp. and Acidiphilium spp., probably related to the higher iron solubility at low pH. At the JL dam, characterized by a banded sediment with higher pH (4.2 to 6.2), more reducing redox potential (?210 mV to 50 mV), and a lower solubility of iron, members of sulfate-reducing genera Syntrophobacter, Desulfosporosinus, and Desulfurella were dominant. The latter was quantified with a newly designed CARD-FISH probe. In layers where sulfate-reducing bacteria were abundant, pH was higher and redox potential and levels of dissolved metals and iron were lower. These results suggest that the attenuation of ARD characteristics is biologically driven by sulfate reducers and the consequent precipitation of metals and iron as sulfides.

Sanchez-Andrea, Irene; Knittel, Katrin; Amann, Rudolf; Amils, Ricardo

2012-01-01

67

Quantification of Tinto River sediment microbial communities: importance of sulfate-reducing bacteria and their role in attenuating acid mine drainage.  

PubMed

Tinto River (Huelva, Spain) is a natural acidic rock drainage (ARD) environment produced by the bio-oxidation of metallic sulfides from the Iberian Pyritic Belt. This study quantified the abundance of diverse microbial populations inhabiting ARD-related sediments from two physicochemically contrasting sampling sites (SN and JL dams). Depth profiles of total cell numbers differed greatly between the two sites yet were consistent in decreasing sharply at greater depths. Although catalyzed reporter deposition fluorescence in situ hybridization with domain-specific probes showed that Bacteria (>98%) dominated over Archaea (<2%) at both sites, important differences were detected at the class and genus levels, reflecting differences in pH, redox potential, and heavy metal concentrations. At SN, where the pH and redox potential are similar to that of the water column (pH 2.5 and +400 mV), the most abundant organisms were identified as iron-reducing bacteria: Acidithiobacillus spp. and Acidiphilium spp., probably related to the higher iron solubility at low pH. At the JL dam, characterized by a banded sediment with higher pH (4.2 to 6.2), more reducing redox potential (-210 mV to 50 mV), and a lower solubility of iron, members of sulfate-reducing genera Syntrophobacter, Desulfosporosinus, and Desulfurella were dominant. The latter was quantified with a newly designed CARD-FISH probe. In layers where sulfate-reducing bacteria were abundant, pH was higher and redox potential and levels of dissolved metals and iron were lower. These results suggest that the attenuation of ARD characteristics is biologically driven by sulfate reducers and the consequent precipitation of metals and iron as sulfides. PMID:22544246

Sánchez-Andrea, Irene; Knittel, Katrin; Amann, Rudolf; Amils, Ricardo; Sanz, José Luis

2012-07-01

68

Aseptically Sampled Organics in Subsurface Rocks From the Mars Analog Rio Tinto Experiment: An Analog For The Search for Deep Subsurface Life on Mars.}  

NASA Astrophysics Data System (ADS)

The subsurface is the key environment for searching for life on planets lacking surface life. Subsurface ecosystems are of great relevance to astrobiology including the search for past/present life on Mars. The surface of Mars has conditions preventing current life but the subsurface might preserve organics and even host some life [1]. The Mars-Analog-Rio-Tinto-Experiment (MARTE) is performing a simulation of a Mars drilling experiment. This comprises conventional and robotic drilling of cores in a volcanically-hosted-massive-pyrite deposit [2] from the Iberian Pyritic Belt (IBP) and life detection experiments applying anti-contamination protocols (e.g., ATP Luminometry assay). The RT is considered an important analog of the Sinus Meridiani site on Mars and an ideal model analog for a deep subsurface Martian environment. Former results from MARTE suggest the existence of a relatively complex subsurface life including aerobic and anaerobic chemoautotrophs and strict anaerobic methanogens sustained by Fe and S minerals in anoxic conditions. A key requirement for the analysis of a subsurface sample on Mars is a set of simple tests that can help determine if the sample contains organic material of biological origin, and its potential for retaining definitive biosignatures. We report here on the presence of bulk organic matter Corg (0.03-0.05 Wt%), and Ntot (0.01-0.04 Wt%) and amount of measured ATP (Lightning MVP, Biocontrol) in weathered rocks (tuffs, gossan, pyrite stockwork from Borehole #8; >166m). This provides key insight on the type of trophic system sustaining the subsurface biosphere (i.e., heterotrophs vs. autotrophs) at RT. ATP data (Relative-Luminosity-Units, RLU) provide information on possible contamination and distribution of viable biomass with core depth (BH#8, and BH#7, ~3m). Avg. 153 RLU, i.e., surface vs. center of core, suggest that cleaness/sterility can be maintained when using a simple sterile protocol under field conditions. Results from this research will support future drilling mission planned on Mars. [1] Boston, P.J., et al., 1992. Icarus 95,300-308; [2] Leistel et al., 1998.

Bonaccorsi, R.; Stoker, C. R.

2005-12-01

69

Organics-bearing Clays from the Rio Tinto (spain): A Novel Analog for the Phyllosilicates Outcrops Seen By Omega-mex  

NASA Astrophysics Data System (ADS)

The Rio Tinto (RT) is considered an important analog of Sinus Meridiani on Mars and an ideal model analog for a subsurface Martian setting [1]. The RT system comprises the upper sequence of an acid rock drainage system where weathered iron -rich rocks, overlain a massive-pyrite deposit. The RT analog site is ideal for testing on the preservation of organics in hematite-rich vs. phyllosilicates-rich environments [3]. It is suggested here that RT near-surface rocks, which embed pockets of Clays, represent also a potential new model analog for the phyllosilicates-rich outcrops seen by OMEGA-MEx on the surface of Mars [5]. Results from the analysis of cores drilled under the 2005 Robotic experiment of the MARTE project (Borehole#7 Site 607cm) [2-3] are presented in this paper. Primary mineral assemblages include hematite, goethite, and Phyllosilicates e.g.,smectite, kaolinite, as quantified by X-ray diffraction [4]. Organic carbon is at low concentration (<0.05%) beneath the soil horizon in most cores dominated by iron minerals but is considerably higher in Phyllosilicate-rich levels i.e., 0.2-0.3Wt% at 385 -550 cm-depth [2-3]. Phyllosilicate-rich terrains have been identified OMEGA/MEx in the Nili Fossae, Mawrth Valles and Candor Chasma regions [e.g., 5]. These outcrops are surrounded by hematite-rich deposits, which are potentially barren in organics [6]. The potential of phyllosilicates to preserve higher amounts of organics/ biosignatures is well known for several Earth environments as well as the RT near subsurface. This potential brings a relevant element for the selection of candidate sites for the MSL mission [e.g., 1]. References: [1]Fernandez-Remolar et al.,2005 EPSL, 240,149-167; [2]Stoker et al., 2007; [3] Bonaccorsi et al., 2007; [4] Sutter et al., 2007 in Astrobiology,MARTE Spec. Issue; [5] Bibring et al., 2006, Science 312, 400-404; [6] Sumner, 2004, JGR 109. Anknowlegments: NASA-Postdoctoral-Program/C.Stoker, B.Sutter, A.F Davila and the MARTE team for valuable suggestions.

Bonaccorsi, Rosalba

2007-12-01

70

76 FR 80430 - Rio Tinto plc and Rio Tinto Limited; Notice of Application  

Federal Register 2010, 2011, 2012, 2013

...2) and 45(a) of the Investment Company Act of 1940 (the...551-6821 (Division of Investment Management, Office of Investment Company Regulation). SUPPLEMENTARY...coal, iron ore, uranium, gold and industrial...

2011-12-23

71

Mensaje para alumnos y padres  

NASA Video Gallery

El astronauta de la NASA José Hernández alienta a los estudiantes a que sigan sus sueños. Hernández también habla acerca del papel que juegan los padres para ayudar a que sus hijos hagan realidad s...

72

Tomografía computarizada (TC) y exploraciones para cáncer  

Cancer.gov

Hoja informativa que describe el procedimiento y la tecnología de exploraciones con tomografía computarizada así como sus usos para el diagnóstico, para exámenes de detección y para tratamiento del cáncer.

73

Centro para la Salud Mundial del NCI  

Cancer.gov

El Centro para la Salud Mundial del NCI coordina actividades de investigación y trabaja con socios nacionales e internacionales para entender y enfrentar la carga que representa el cáncer a nivel mundial.

74

Novos currículos de Geologia no Ensino Secundário português: contributos da Associação Portuguesa de Geólogos  

Microsoft Academic Search

The Education and Training in Geology are critical to the development of varied competences, concurring to an eclectic scientific literacy that is useful to a lucid citizenship in the Society of the present and future. For the Se - condary School level, the Geology learning programmes should be organized in order to: (1) include the core issues\\/ concepts needed for

Edite Bolacha; António Mateus; Escola Secundária; D. Dinis; Manuel Teixeira Gomes

2008-01-01

75

La Cometa 67P Churyumov-Gerasimenko el il contributo degli astrofili italiani alla missione ROSETTA  

NASA Astrophysics Data System (ADS)

Comet 67P Churyumov-Gerasimenko, the new target of the ROSETTA spacecraft, was oberved during the 2002/2003 apparition, displacing an unusual tail. The tail was compatible with a neck-line structure and this implies a high nuclear activity far before perihelion. Images and data from the current and previous apparitions show that the comet reaches the maximum brightening after the perihelion passage (Af[rho] = 200-250 cm).

Milani, Giannantonio

2004-08-01

76

?-Cyclodextrin- para-aminosalicylic acid inclusion complexes  

NASA Astrophysics Data System (ADS)

Complex formation of ?-cyclodextrin with para-aminosalicylic acid in buffer solutions is studied by UV spectroscopy. It is found that the stoichiometric proportion of the components in the ?-cyclodextrin-para-aminosalicylic acid inclusion complex is 1:1. The Ketelar equation is used to calculate the stability constants of the inclusion complexes at different temperatures. The thermodynamic parameters of the complex formation process (?G, ?H, ?S) are calculated using the van't Hoff equation. The 1:1 ?-cyclodextrin-para-aminosalicylic acid inclusion complex is prepared in solid form and its characteristics are determined by IR spectroscopic and x-ray diffraction techniques.

Roik, N. V.; Belyakova, L. A.; Oranskaya, E. I.

2010-11-01

77

Preguntas para el doctor sobre el cáncer  

Cancer.gov

Serie de preguntas, organizadas por tema, que los pacientes con cáncer pueden hacerle al médico o a otros miembros de su equipo de atención médica para conocer más acerca de su tipo de cáncer y lo que pueden esperar.

78

Una técnica para filtrar patrones de fringing  

NASA Astrophysics Data System (ADS)

Se presenta una nueva técnica para filtrar los patrones de fringing producidos en los CCDs tipo RCA. El método consiste en construir un mapa con los ángulos de inclinación de las franjas en cada punto de la imagen. Este mapa es ulteriormente utilizado para alinear con el patrón de interferencia una ventana estrecha, sobre la que se aplica un filtro de mediana. Este procedimiento permite eliminar la mayor parte del ruido del patrón de fringing sin destruirlo.

Ostrov, P. G.

79

The ParaScope parallel programming environment  

NASA Technical Reports Server (NTRS)

The ParaScope parallel programming environment, developed to support scientific programming of shared-memory multiprocessors, includes a collection of tools that use global program analysis to help users develop and debug parallel programs. This paper focuses on ParaScope's compilation system, its parallel program editor, and its parallel debugging system. The compilation system extends the traditional single-procedure compiler by providing a mechanism for managing the compilation of complete programs. Thus, ParaScope can support both traditional single-procedure optimization and optimization across procedure boundaries. The ParaScope editor brings both compiler analysis and user expertise to bear on program parallelization. It assists the knowledgeable user by displaying and managing analysis and by providing a variety of interactive program transformations that are effective in exposing parallelism. The debugging system detects and reports timing-dependent errors, called data races, in execution of parallel programs. The system combines static analysis, program instrumentation, and run-time reporting to provide a mechanical system for isolating errors in parallel program executions. Finally, we describe a new project to extend ParaScope to support programming in FORTRAN D, a machine-independent parallel programming language intended for use with both distributed-memory and shared-memory parallel computers.

Cooper, Keith D.; Hall, Mary W.; Hood, Robert T.; Kennedy, Ken; Mckinley, Kathryn S.; Mellor-Crummey, John M.; Torczon, Linda; Warren, Scott K.

1993-01-01

80

MÉTODOS PARA DETERMINAÇÃO DA DENSIDADE BÁSICA DE CAVACOS PARA CONÍFERAS E FOLHOSAS  

Microsoft Academic Search

1 - INTRODUÇÃO A densidade da madeira é uma característica complexa resultante da combinação de diversos fatôres. Existem inúmeros trabalhos mostrando sua relação com as dimensões das fibras, particularmente espessura da parede, volume dos vasos e parênquimas, proporção entre madeira primaveril e outonal, e arranjo dos elementos anatômicos. Êste assunto tem sido intensivamente estudado para as coníferas, porém para as

Celso Edmundo; Bochetti Foelkel; Maria Aparecida Mourão Brasil; Luiz Ernesto; George Barrichelo

81

Searching for an Acidic Aquifer in the Rio Tinto Basin: First Geobiology Results of MARTE Project  

NASA Technical Reports Server (NTRS)

Among the conceivable modern habitats to be explored for searching life on Mars are those potentially developed underground. Subsurface habitats are currently environments that, under certain physicochemical circumstances, have high thermal and hydrochemical stability [1, 2]. In planets like Mars lacking an atmospheric shield, such systems are obviously protected against radiation, which strongly alters the structure of biological macromolecules. Low porosity but fractured aquifers currently emplaced inside ancient volcano/sedimentary and hydrothermal systems act as excellent habitats [3] due to its thermal and geochemical properties. In these aquifers the temperature is controlled by a thermal balance between conduction and advection processes, which are driven by the rock composition, geological structure, water turnover of aquifers and heat generation from geothermal processes or chemical reactions [4]. Moreover, microbial communities based on chemolithotrophy can obtain energy by the oxidation of metallic ores that are currently associated to these environments. Such a community core may sustain a trophic web composed of non-autotrophic forms like heterotrophic bacteria, fungi and protozoa.

Fernandez-Remolar, D. C.; Prieto-Ballesteros, O.; Stoker, C.

2004-01-01

82

PRODUCTOS TUBULARES PARA REDUCIR EL COSTO TOTAL  

Microsoft Academic Search

Nuevos equipos, materiales, herramientas y operaciones se han desarrollado con el objetivo de reducir los tiempos de ejecución y\\/o de completación de los pozos y por lo tanto el costo operativo y de materiales. En este trabajo nos ocuparemos de mencionar algunos de los métodos y materiales alternativos para llevar a cabo estas operaciones, especialmente en los que están involucradas

Daniel Ghidina; Fabián Benedetto

83

Sistema de Web Mapping para Geologia Médica  

Microsoft Academic Search

Resumo - Este trabalho apresenta um sistema de Web Mapping para pesquisa em Geologia Médica, no qual, por meio de uma navegação em mapas interativos, epidemiologistas visualizam as distribuições espaciais de teores de elementos químicos em águas não tratadas (bacias hidrográficas) e dos coeficientes de morbi-mortalidade por doenças nos municípios. A sobreposição desses temas compõe um mapa onde se podem

Humberto Cereser Ibañez; Marilea Vieira de Camargo; Hélio Pedrini

84

Para-hydrogen perspectives in hyperpolarized NMR.  

PubMed

The first instance of para-hydrogen induced polarization (PHIP) in an NMR experiment was serendipitously observed in the 1980s while investigating a hydrogenation reaction (Seldler et al., 1983; Bowers and Weitekamp, 1986, 1987; Eisenschmid et al., 1987) [1-4]. Remarkably a theoretical investigation of the applicability of para-hydrogen as a hyperpolarization agent was being performed in the 1980's thereby quickly providing a theoretical basis for the PHIP-effect (Bowers and Weitekamp, 1986) [2]. The discovery of signal amplification by a non-hydrogenating interaction with para-hydrogen has recently extended the interest to exploit the PHIP effect, as it enables investigation of compounds without structural alteration while retaining the advantages of spectroscopy with hyperpolarized compounds [5]. In this article we will place more emphasis of the future applications of the method while only briefly discussing the efforts that have been made in the understanding of the phenomenon and the development of the method so far. PMID:23932399

Glöggler, Stefan; Colell, Johannes; Appelt, Stephan

2013-10-01

85

Planificación para la etapa final de la vida  

Cancer.gov

Información para pacientes, sus familiares y amigos sobre el cuidado del paciente terminal, la planificación para el final de la vida, y la aflicción, el duelo y manejo de la pérdida de un ser querido.

86

EVALUACIÓN ERGONÓMICA DEL USO DE BOMBAS PORTATILES PARA FUMIGAR  

Microsoft Academic Search

Como primera actividad se observó al operario trabajando, anotando cualquier detalle que fuera relevante para la investigación, posteriormente se evaluó con el método “e-RULA” el uso de las mochilas para fumigar cuando se encuentran con el liquido para fumigar y cuando se encuentran vacías. Adicionalmente se aplicaron encuestas a 30 empleados campesinos (hombres) que laboran en ranchos y tienen por

Karla CeliaVázquez Arroyo; Hugo Cesar Ramos Herrera; Dulce María García Gómez; Juan Luis Hernández Arellano

2007-01-01

87

The para radiation effects current simulator  

NASA Astrophysics Data System (ADS)

The Parametric Analysis of Radiation effects software development is given the general title PARA. This report describes the development of algorithms and source codes for the simulation of radiation effects on CMOS ICs. The project concentrated on the simulation of total dose effects and the ways to establish/predict the operational lifetime and radiation tolerance of ICs. The switch level simulator incorporates the capability to assign bias dependent post-irradiation drive parameters to transistors within a microcircuit and to calculate propagation delays based on those parameters. This permits test vectors to be assigned based on worst case post-irradiation propagation delays.

Bhuva, Bharat; Kerns, Sherra

1992-01-01

88

On q-DEFORMED Para Oscillators and PARA-q Oscillators  

NASA Astrophysics Data System (ADS)

Three generalized commutation relations for a single mode of the harmonic oscillator which contains para-bose and q oscillator commutation relations are constructed. These are shown to be inequivalent. The coherent states of the annihilation operator for these three cases are also constructed.

Kumari, M. Krishna; Shanta, P.; Chaturvedi, S.; Srinivasan, V.

89

Tributación Simplificada para Pequeñas y Microempresas: Análisis y Propuesta de Reforma para el Caso Chileno  

Microsoft Academic Search

Este trabajo analiza las principales debilidades de los actuales regímenes simplificados de tributación a la renta en Chile y propone un nuevo modelo para la tributación dirigido a la pequeña y microempresa (PYME). El diagnóstico indica que los actuales regímenes simplificados son, en general, efectivos en reducir los costos de cumplimiento. No obstante, detecta tres deficiencias que perjudican fuertemente su

Patricio Barra

2005-01-01

90

ParaView for climate scientists  

NASA Astrophysics Data System (ADS)

ParaView is an immensely popular scientific visualization framework that provides a variety of tools necessary for scientific visualization especially dealing with large data that ultimately leads to better understanding of simulation and non simulation data. The Ultrascale Visualization Climate Data Analysis Tools (UV-CDAT), is a powerful and complete front-end to a rich set of visual-data exploration and analysis capabilities well suited for climate-data analysis problems. This talk describes integration of Paraview within UV-CDAT framework by leveraging python interface of Paraview and various new features added to uvcdat and Paraview specifically targeting climate data such as new readers, filters and parallel spatiotemporal capabilities.

Chaudhary, A.

2012-12-01

91

On Lightlike Geometry of Para-Sasakian Manifolds  

PubMed Central

We study lightlike hypersurfaces of para-Sasakian manifolds tangent to the characteristic vector field. In particular, we define invariant lightlike hypersurfaces and screen semi-invariant lightlike hypersurfaces, respectively, and give examples. Integrability conditions for the distributions on a screen semi-invariant lightlike hypersurface of para-Sasakian manifolds are investigated. We obtain a para-Sasakian structure on the leaves of an integrable distribution of a screen semi-invariant lightlike hypersurface.

Acet, Bilal Eftal; K?l?c, Erol

2014-01-01

92

Il contributo di G. Braga alla Sociologia del linguaggio (The Contributions of G. Braga to the Sociology of Language).  

ERIC Educational Resources Information Center

Discusses Braga's contribution to the study of the sociology of language. Braga developed a dynamic interdisciplinary model of verbal communication based on theories of sociology and linguistics and stressed the importance of language in the acculturation of an individual and in the determination of that individual's status in society. (CFM)

Tessarolo, Marisella

1989-01-01

93

Benchmarking para Investimentos socialmente Responsáveis: ISE a experiência brasileira  

Microsoft Academic Search

Este artigo apresenta os desafios da criação e o desenvolvimento de uma nova ferramenta para o mercado de ações - o Índice de Sustentabilidade Empresarial (ISE) da Bovespa. Pretende-se demonstrar como o ISE tem se tornado uma ferramenta para destacar as empresas com estratégia de geração de valor por meio da sustentabilidade através da melhora contínua da metodologia. Os índices

ROBERTA SIMONETTI

94

Ortho/Para Ratio of Water Vapor in Comet Halley.  

National Technical Information Service (NTIS)

The ortho/para ratio of H2O is shown to be an invariant in the cometary coma. The dependence of ortho-para ratio on temperature in thermal equilibrium is given, and the nuclear-spin-temperature is defined. Its relation to the physical temperature of the c...

M. J. Mumma H. P. Larson H. A. Weaver

1986-01-01

95

Towards a double field theory on para-Hermitian manifolds  

SciTech Connect

In a previous paper, we have shown that the geometry of double field theory has a natural interpretation on flat para-Kähler manifolds. In this paper, we show that the same geometric constructions can be made on any para-Hermitian manifold. The field is interpreted as a compatible (pseudo-)Riemannian metric. The tangent bundle of the manifold has a natural, metric-compatible bracket that extends the C-bracket of double field theory. In the para-Kähler case, this bracket is equal to the sum of the Courant brackets of the two Lagrangian foliations of the manifold. Then, we define a canonical connection and an action of the field that correspond to similar objects of double field theory. Another section is devoted to the Marsden-Weinstein reduction in double field theory on para-Hermitian manifolds. Finally, we give examples of fields on some well-known para-Hermitian manifolds.

Vaisman, Izu [Department of Mathematics, University of Haifa, Haifa (Israel)] [Department of Mathematics, University of Haifa, Haifa (Israel)

2013-12-15

96

Properties of Armos Para-Aramid Fibres in Conditions of Use. Comparison with Other Para-Aramids  

Microsoft Academic Search

The mechanical, thermal, and hygroscopic properties of Armos fibres and thread and their resistance to active media and other effects during use were analyzed. In comparing the structure and properties of Armos with other types of para-aramid fibres and thread, it was found that in the para-aramid series, Armos is distinguished by a unique combination of strength and flame resistance.

K. E. Perepelkin; N. N. Machalaba; V. A. Kvartskheliya

2001-01-01

97

¿Son las políticas locales una buena estrategia para dinamizar el mercado de trabajo? Algunos elementos para el caso colombiano  

Microsoft Academic Search

Resumen: En períodos de bajo crecimiento económico, tiempos de recesión o crisis económica, implementar una política fiscal contra-cíclica puede ser una herramienta fundamental para crear empleo y dinamizar la economía. En Colombia, específicamente en las principales ciudades del país existe una posibilidad concreta para que los gobiernos locales, a través de incrementos del gasto de inversión, impacten positivamente en la

Diana Galvis G; Mauricio López Gonzalez

2010-01-01

98

A Model of the Para-Terphenyl Dye Laser (Un Modele du Laser a Colorant Para-Terphenyl).  

National Technical Information Service (NTIS)

A theoretical model for a Para-Terphenyl dye laser pumped by an excimer laser has been developed. A new set of reaction-rate coefficients for Para-Terphenyl has been established. The problem of spontaneous emission in a dye has been solved analytically. T...

G. Fournier

1981-01-01

99

Autoguía para el telescopio 2,15 mts de CASLEO  

NASA Astrophysics Data System (ADS)

Se está desarrollando un sistema de autoguía para el telescopio de 2,15 mts. El mismo se realizará aprovechando el Offset Guider. Al ocular móvil de éste se vinculará alguna cámara digital (ST4-ST7-CH250) para lograr la visión del objeto. El funcionamiento del equipo será el siguiente: primero, dadas las coordenadas del objeto a observar, se tomarán las coordenadas del telescopio para que, a través de una base de datos, se determine un campo de objetos que sirvan para la cámara de visión, luego, la PC obtendrá el offset entre la estrella de observación y la estrella seleccionada como guía, este valor será trasladado a los motores que posicionarán en forma automática el ocular. Una vez que la estrella es visualizada en la cámara (monitor de PC ) se correrá el programa que guiará el telescopio automáticamente.

Aballay, J. A.; Casagrande, A. R.; Pereyra, P. F.; Marún, A. H.

100

Control del dolor: Apoyo para las personas con cáncer  

Cancer.gov

Libro sobre el control del dolor en pacientes con cáncer. Cubre los métodos y medicinas, así como los efectos físicos y emocionales del dolor. Es una adaptación cultural para el público de habla hispana del libro en inglés Pain Control.

101

Confocal Interferometer Without the Para-Axial Approximation.  

National Technical Information Service (NTIS)

The perturbed eigenfunctions of the confocal cavity without the para-axial condition are obtained. It is shown that in spite of the perturbation being small, the eigenfunctions change appreciably. (Atomindex citation 10:459675)

E. Gerck O. Andrade

1978-01-01

102

La quimioterapia y usted: Apoyo para las personas con cáncer  

Cancer.gov

Publicación para personas que van a recibir o que ya están recibiendo quimioterapia contra el cáncer. Contiene información sobre la quimioterapia y sus efectos secundarios y describe cómo puede cuidarse durante y después del tratamiento.

103

La radioterapia y usted: Apoyo para las personas con cáncer  

Cancer.gov

E-book para personas que van a recibir o que ya están recibiendo radioterapia contra el cáncer. Contiene información sobre la radioterapia y sus efectos secundarios y describe cómo puede cuidarse durante y después del tratamiento.

104

Preguntas para el doctor si tiene un cáncer avanzado  

Cancer.gov

Serie de preguntas que los pacientes con cáncer pueden hacerle al médico sobre las opciones de tratamiento si el cáncer es avanzado, las formas de controlar los síntomas y cómo prepararse para la etapa final de la vida.

105

La terapia hormonal para la menopausia y el cáncer  

Cancer.gov

Hoja informativa acerca de los resultados de los estudios sobre el uso de la terapia hormonal para la menopausia. Incluye información sobre el efecto de esta terapia en el cuerpo y explica los riesgos y beneficios del uso de hormonas.

106

40 CFR 721.9520 - Methylated-para-rosaniline salt of a trisulfonated triarylmethane dye (generic).  

Code of Federal Regulations, 2010 CFR

... false Methylated-para-rosaniline salt of a trisulfonated triarylmethane dye...9520 Methylated-para-rosaniline salt of a trisulfonated triarylmethane dye...generically as methylated-para-rosaniline salt of a trisulfonated triarylmethane...

2010-07-01

107

Chylous ascites following para-aortic lymphadenectomy: a case report  

Microsoft Academic Search

Background. Chylous ascites is an uncommon complication following para-aortic lymph node dissection in the management of gynecologic malignancies. Treatment options are serial paracentesis, medium-chain triglyceride diet, total parenteral nutrition and somatostatin as conservative management and peritoneovenous shunting, and surgical exploration for refractory cases.Case. A 31-year-old female patient developed chylous ascites following para-aortic lymph node dissection for borderline mucinous tumor of

Nurettin Boran; Aylin Pelin Cil; Gokhan Tulunay; Nejat Ozgul; M. Faruk Kose

2004-01-01

108

Cooling by conversion of para to ortho-hydrogen  

NASA Technical Reports Server (NTRS)

The cooling capacity of a solid hydrogen cooling system is significantly increased by exposing vapor created during evaporation of a solid hydrogen mass to a catalyst and thereby accelerating the endothermic para-to-ortho transition of the vapor to equilibrium hydrogen. Catalyst such as nickel, copper, iron or metal hydride gels of films in a low pressure drop catalytic reactor are suitable for accelerating the endothermic para-to-ortho conversion.

Sherman, A. (inventor)

1983-01-01

109

ParaText : scalable text modeling and analysis.  

SciTech Connect

Automated processing, modeling, and analysis of unstructured text (news documents, web content, journal articles, etc.) is a key task in many data analysis and decision making applications. As data sizes grow, scalability is essential for deep analysis. In many cases, documents are modeled as term or feature vectors and latent semantic analysis (LSA) is used to model latent, or hidden, relationships between documents and terms appearing in those documents. LSA supplies conceptual organization and analysis of document collections by modeling high-dimension feature vectors in many fewer dimensions. While past work on the scalability of LSA modeling has focused on the SVD, the goal of our work is to investigate the use of distributed memory architectures for the entire text analysis process, from data ingestion to semantic modeling and analysis. ParaText is a set of software components for distributed processing, modeling, and analysis of unstructured text. The ParaText source code is available under a BSD license, as an integral part of the Titan toolkit. ParaText components are chained-together into data-parallel pipelines that are replicated across processes on distributed-memory architectures. Individual components can be replaced or rewired to explore different computational strategies and implement new functionality. ParaText functionality can be embedded in applications on any platform using the native C++ API, Python, or Java. The ParaText MPI Process provides a 'generic' text analysis pipeline in a command-line executable that can be used for many serial and parallel analysis tasks. ParaText can also be deployed as a web service accessible via a RESTful (HTTP) API. In the web service configuration, any client can access the functionality provided by ParaText using commodity protocols ... from standard web browsers to custom clients written in any language.

Dunlavy, Daniel M.; Stanton, Eric T.; Shead, Timothy M.

2010-06-01

110

Mars Analog Rio Tinto Experiment (MARTE): An Experimental Demonstration of Key Technologies for Searching for Life on Mars  

NASA Technical Reports Server (NTRS)

The discovery of near surface ground ice by the Mars Odyssey mission and the abundant evidence for recent Gulley features observed by the Mars Global Surveyor mission support longstanding theoretical arguments for subsurface liquid water on Mars. Thus, implementing the Mars program goal to search for life points to drilling on Mars to reach liquid water, collecting samples and analyzing them with instrumentation to detect in situ organisms and biomarker compounds. Searching for life in the subsurface of Mars will require drilling, sample extraction and handling, and new technologies to find and identify biomarker compounds and search for living organisms.

Stoker, Carol

2004-01-01

111

The Search for Subsurface Life on Mars: Results from the MARTE Analog Drill Experiment in Rio Tinto, Spain  

NASA Astrophysics Data System (ADS)

The Mars Analog Research and Technology (MARTE) experiment has developed an automated drilling system on a simulated Mars lander platform including drilling, sample handling, core analysis and down-hole instruments relevant to searching for life in the Martian subsurface.

Stoker, C. R.; Lemke, L. G.; Cannon, H.; Glass, B.; Dunagan, S.; Zavaleta, J.; Miller, D.; Gomez-Elvira, J.

2006-03-01

112

Direct His bundle and paraHisian cardiac pacing.  

PubMed

The success rate of direct His bundle pacing (DHBP) and paraHisian pacing has improved remarkably in the last 3-5 years with the advent of dedicated fixation systems that have reduced procedural duration, dislodgement rate, and fluoroscopy time. The methodology of DBHP remains still more complex than paraHisian pacing and is associated with high-pacing thresholds. Thus, DHBP entails greater battery current drain and reduced device longevity. A shift toward paraHisian pacing (which is fusion pacing of myocardium and His bundle) has occurred because its implementation is easier and the electrical parameters are superior to those of DBHP. Currently, an additional safety lead is inserted at the RV apex or outflow tract to prevent asystole, especially in patients with pure DHBP. It is often possible to avoid a safety lead with paraHisian pacing because ventricular pacing is virtually assured on a long-term basis via myocardial capture. DBHP and paraHisian pacing can be achieved in a substantial proportion of patients with varying grades of narrow QRS AV block or after AV junctional ablation and in some patients with the ECG manifestation of bundle branch block caused by an intraHisian lesion. Preliminary observations suggest that DHBP may be useful in some patients requiring cardiac resynchronization if it produces a narrow QRS complex because the site of an intraHisian lesion responsible for left bundle branch block is above the site of DHBP. PMID:22537323

Zanon, Francesco; Barold, S S

2012-04-01

113

El diseño final del espectrógrafo de banco (EBASIM) para CASLEO  

NASA Astrophysics Data System (ADS)

Utilizando el código de óptica ACCOS V se ha finalizado el diseño del espectrógrafo de banco para CASLEO. En una comunicación anterior habíamos indicado que utilizaríamos un colimador de 150 mm de diámetro con un radio de curvatura de 1540 mm. Para el espejo cámara, que tiene un diámetro de 200 mm, el radio de curvatura es de 1200 mm, ambos radios con una tolerancia no mayor a los 3 mm. En la presente, se informa sobre los detalles finales del cálculo del espectrógrafo que incluye el cómputo para 5 longitudes de onda diferentes y alrededor de 100 rayos. En todos los casos el 75 % de energía está dentro de un diámetro de 13 micrones. El diseño ha sido probado entre 3500 Å hasta 9000 Å con resultados satisfactorios.

Simmons, J.; Levato, H.

114

Laparoscopic repair of a right para duodenal hernia.  

PubMed

Para duodenal hernia is among the uncommon and rare causes of intestinal obstruction, but it is the most common type of internal hernia in abdomen and accounts for more than half of cases that do occur. Here, we are reporting a case of right Para duodenal hernia, reduced and repaired laparoscopically. This thirteen year old girl presented to us with features of small bowel obstruction of two days duration. Plain abdominal X-ray showed multiple fluid levels confined to right side of abdomen. A diagnostic laparoscopy was done under General Anaesthesia. Right Para duodenal hernia was found with small bowel confined to the right side between the ascending colon and hepatic flexure of colon. Laparoscopic reduction of contents of the hernia was done starting from the Ileocaecal junction. Hernial opening was closed laparoscopically with nonabsorbable suture. Patient is quite well till date and has had no recurrence of symptoms. PMID:20407574

Bhartia, Vishnu; Kumar, Anil; Khedkar, Indira; Savita, K S; Goel, N

2009-10-01

115

Laparoscopic repair of a right para duodenal hernia  

PubMed Central

Para duodenal hernia is among the uncommon and rare causes of intestinal obstruction, but it is the most common type of internal hernia in abdomen and accounts for more than half of cases that do occur. Here, we are reporting a case of right Para duodenal hernia, reduced and repaired laparoscopically. This thirteen year old girl presented to us with features of small bowel obstruction of two days duration. Plain abdominal X-ray showed multiple fluid levels confined to right side of abdomen. A diagnostic laparoscopy was done under General Anaesthesia. Right Para duodenal hernia was found with small bowel confined to the right side between the ascending colon and hepatic flexure of colon. Laparoscopic reduction of contents of the hernia was done starting from the Ileocaecal junction. Hernial opening was closed laparoscopically with nonabsorbable suture. Patient is quite well till date and has had no recurrence of symptoms

Bhartia, Vishnu; Kumar, Anil; Khedkar, Indira; Savita, K S; Goel, N

2009-01-01

116

Astronomia para/com crianças carentes em Limeira  

NASA Astrophysics Data System (ADS)

Em 2001, o Instituto Superior de Ciências Aplicadas (ISCA Faculdades de Limeira) iniciou um projeto pelo qual o Observatório do Morro Azul empreendeu uma parceria com o Centro de Promoção Social Municipal (CEPROSOM), instituição mantida pela Prefeitura Municipal de Limeira para atender crianças e adolescentes carentes. O CEPROSOM contava com dois projetos: Projeto Centro de Convivência Infantil (CCI) e Programa Criança e Adolescente (PCA), que atendiam crianças e adolescentes em Centros Comunitários de diversas áreas da cidade. Esses projetos têm como prioridades estabelecer atividades prazerosas para as crianças no sentido de retirá-las das ruas. Assim sendo, as crianças passaram a ter mais um tipo de atividade - as visitas ao observatório. Este painel descreve as várias fases do projeto, que envolveu: reuniões de planejamento, curso de Astronomia para as orientadoras dos CCIs e PCAs, atividades relacionadas a visitas das crianças ao Observatório, proposta de construção de gnômons e relógios de Sol nos diversos Centros Comunitários de Limeira e divulgação do projeto na imprensa. O painel inclui discussões sobre a aprendizagem de crianças carentes, relatos que mostram a postura das orientadoras sobre a pertinência do ensino de Astronomia, relatos do monitor que fez o atendimento no Observatório e o que o número de crianças atendidas representou para as atividades da instituição desde o início de suas atividades e, em particular, em 2001. Os resultados são baseados na análise de relatos das orientadoras e do monitor do Observatório, registros de visitas e matérias da imprensa local. Conclui com uma avaliação do que tal projeto representou para as Instituições participantes. Para o Observatório, em particular, foi feita uma análise com relação às outras modalidades de atendimentos que envolvem alunos de escolas e público em geral. Também é abordada a questão do compromisso social do Observatório na educação do público em questão.

Bretones, P. S.; Oliveira, V. C.

2003-08-01

117

Usina de ciências: um espaço pedagógico para aprendizagens múltiplas  

NASA Astrophysics Data System (ADS)

Entendemos que o Ensino de Astronomia é especialmente apropriado para motivar os alunos e aprofundar conteúdos em diversas áreas do conhecimento, pois envolve temas ligados à Física, Matemática, Química, Computação, Tratamento de Imagens e Instrumentação de Alta Precisão, além daqueles pertinentes as áreas de Geografia, História e Antropologia. Contudo, apesar do caráter interdisciplinar que esta ciência possui, a realidade atual é que a maioria dos professores em sala de aula não foram devidamente capacitados, durante o período de formação acadêmica, para ministrar conteúdos de Astronomia nos atuais Ensinos Fundamental e Médio. Neste trabalho, discutiremos de maneira ampla, num primeiro momento, a realidade do atual ensino de ciências praticado no Estado da Bahia, apontando por dependência administrativa, o crescimento e a redução do número de escolas, da taxa de analfabetismo por faixa etária, da escolarização, do atendimento, da aprovação, reprovação e abandono, de equipamentos e laboratórios e o grau de formação dos nossos atuais professores em pleno exercício de atividade docente. Num segundo momento, discutiremos o papel do Observatório Astronômico Antares/UEFS dentro desse contexto, ou seja, suas ações implementadas ao longo dos últimos anos e em particular, o recente projeto de extensão Ensino e Difusão de Astronomia, financiado pela Fundação Vitae, que procura traduzir no lúdico, no brincar de ciências, um espaço pedagógico para aprendizagens múltiplas. Neste, o papel do professor multiplicador associado ao laboratório de kits didáticos, de fácil construção e manipulação (alguns dos quais serão mostrados), perfazem os principais veículos para o desenvolvimento de conhecimentos, atitudes, habilidades e valores que preparam os nossos alunos para a carreira técnico-científica e para sua participação crítica e criativa na Sociedade.

Martin, V. A. F.; Poppe, P. C. R.; Orrico, A. C. P.; Pereira, M. G.

2003-08-01

118

Instrumentos económicos para la gestión de residuos sólidos  

Microsoft Academic Search

Esta presentación discute industria del reciclaje, incluye el caso de botellas PET en Río de Janeiro y el caso de sistema reciclaje de la Municipalidad de La Reina, Santiago; mercado de servicios, incluye el caso de apertura del mercado para usuarios no residenciales en Río de Janeiro y el caso de participación privada en Santiago; gestión integral, incluye el caso

Jorge Ducci

2003-01-01

119

Para-acetabular periarthritis calcarea: Its radiographic manifestations  

Microsoft Academic Search

On retrospective reviews of radiographs, periarthritis calcarea was distinguished from os acetabula by interval radiographic progression and regression. Among 59 men and 51 women, there were 137 instances of para-acetabular calcifications and ossifications, which were morphologically classified as 58 discrete, 58 amorphous, and 21 segmented types. Correlations with other radiographic abnormalities, symptoms, signs, and laboratory abnormalities were sought, but not

Akira Kawashima; Sadayuki Murayama; Toshiyuki Ohuchida; Walter J. Russell

1988-01-01

120

Notas para la Regulación Eficiente de la Transmisión Eléctrica  

Microsoft Academic Search

El proyecto de “ley corta” de electricidad propone importantes modificaciones a la actual regulación de la transmisión eléctrica en Chile. En este artículo desarrollamos un modelo simple para analizar dos de las propuestas centrales del proyecto: (i) el traspaso directo de parte de los costos de transmisión a los consumidores, y (ii) la planificación centralizada de la expansión de la

Juan Pablo Montero; Salvador Valdés

2003-01-01

121

Tumours Linked to Para-Occupational Exposure to Airborne Asbestos  

Microsoft Academic Search

Members of the households of former asbestos workers are at a higher risk of dying from mesothelioma resulting from asbestos exposure from cleaning asbestos-contaminated working clothes of their relatives at home. The lung fibre burdens of some of those who develop mesothelioma are similar even to those of former asbestos workers. Such people are said to be para-occupation- ally exposed.

Joachim Schneider; Hans-Joachim Woitowitz

1996-01-01

122

Nuevos sistemas de frecuencia intermedia para el IAR  

Microsoft Academic Search

Se presenta el diagrama en bloques de los nuevos sistemas de Frecuencia Intermedia para los dos radiómetros instalados en el IAR. Entre las características más importantes del sistema podemos mencionar la posibilidad de conectar cualquiera de las dos antenas a los ``backend\\

J. C. Olalde; D. Perilli; J. J. Larrarte

1996-01-01

123

Fungi associated with leaf litter of para rubber (Hevea brasiliensis)  

Microsoft Academic Search

The objective of this research was to study the diversity of fungi associated with the degradation of para rubber leaf litter. Samples were collected at three periods in 2010: January (during the late rainy season), April (during the dry season) and July (early in the rainy season) in Nakhon Si Thammarat and Songkhla Provinces, both in southern Thailand. Each sample

P. Seephueak; V. Petcharat; S. Phongpaichit

2010-01-01

124

Analyzing and Visualizing Cosmological Simulations with ParaView  

SciTech Connect

The advent of large cosmological sky surveys - ushering in the era of precision cosmology - has been accompanied by ever larger cosmological simulations. The analysis of these simulations, which currently encompass tens of billions of particles and up to a trillion particles in the near future, is often as daunting as carrying out the simulations in the first place. Therefore, the development of very efficient analysis tools combining qualitative and quantitative capabilities is a matter of some urgency. In this paper, we introduce new analysis features implemented within ParaView, a fully parallel, open-source visualization toolkit, to analyze large N-body simulations. A major aspect of ParaView is that it can live and operate on the same machines and utilize the same parallel power as the simulation codes themselves. In addition, data movement is in a serious bottleneck now and will become even more of an issue in the future; an interactive visualization and analysis tool that can handle data in situ is fast becoming essential. The new features in ParaView include particle readers and a very efficient halo finder that identifies friends-of-friends halos and determines common halo properties, including spherical overdensity properties. In combination with many other functionalities already existing within ParaView, such as histogram routines or interfaces to programming languages like Python, this enhanced version enables fast, interactive, and convenient analyses of large cosmological simulations. In addition, development paths are available for future extensions.

Woodring, Jonathan [Los Alamos National Laboratory (LANL); Heitmann, Katrin [ORNL; Ahrens, James P [ORNL; Fasel, Patricia [Los Alamos National Laboratory (LANL); Hsu, Chung-Hsing [ORNL; Habib, Salman [ORNL; Pope, Adrian [Los Alamos National Laboratory (LANL)

2011-01-01

125

Do lar para as ruas: capitalismo, trabalho e feminismo  

Microsoft Academic Search

Neste artigo, busca-se discutir as influências sociais, culturais e econômicas que contribuíram para a formulação de um discurso e práticas coletivas feministas 1 . Com efeito, esse discurso passou a se manifestar na Europa e nos Estados Unidos ainda no século XIX, sendo que, no caso do Brasil, o mesmo fenômeno ocorreu nas últimas décadas deste e nos primórdios do

Natalia Pietra Méndez

126

Ambiente para la Captura y Administración de Versiones de Modelos  

Microsoft Academic Search

El proceso de desarrollo de modelos para la gestión, investigación, producción, etc., en general involucra actividades creativas, que frecuentemente son poco estructuradas, es decir, no existe un flujo de trabajo definido previamente. Durante este proceso se genera un gran número de modelos de distinto nivel de abstracción del objeto que se desarrolla, el cual puede consistir en un sistema de

Diego Sánchez Schenone; Silvio Gonnet; Horacio Leone

127

ACUTE TOXICITY OF PARA-NONYLPHENOL TO SALTWATER ANIMALS  

EPA Science Inventory

?para-Nonylphenol (PNP), a mixture of alkylphenols used in producing nonionic surfactants, is distributed widely in surface waters and aquatic sediments, where it can affect saltwater species. This article describes a database for acute toxicity of PNP derived for calculating a n...

128

Terapias adyuvantes y neoadyuvantes para el cáncer de seno  

Cancer.gov

Hoja informativa que explica las terapias adyuvantes (tratamiento que se administra además de la terapia primaria para aumentar la posibilidad de supervivencia a largo plazo) y las neoadyuvantes (terapia que se administra antes de la terapia principal). Contiene información sobre los efectos secundarios y sobre los riesgos y beneficios de estas terapias.

129

ParaView and visualization on the TeraGrid  

NSDL National Science Digital Library

Overview on starting and running ParaView on the TeraGrid. With provided data, the tutorial instructs how to load the data, change the display mode, and edit the color map. It also shows how to add isosurfaces and cutting planes.

Teragrid

130

Comparison of dissociation tendencies of meta- & para- trifluorotolylglycine methyl esters and meta- & para- tolylglycine methyl esters in ESI-MS  

Microsoft Academic Search

Peptide fragmentation is an integral part of an evolving field commonly referred to as proteomics. Understanding of peptide fragmentation is vital to continued proteomic research. The frame work of this study was the benzylglycine methyl ester with either a methyl or trifluoromethyl constituent in the para- and meta-positions of the benzyl ring. The glycine methyl ester was coupled to the

Dale Kerstetter; Anthony Vu; Adam Graichen; Richard Vachet; Idia Tokunboh; Mike Van Stipdonk

131

NCI Anuncia Contribuciones para Incrementar Acceso de Minorías a Información sobre el Cáncer  

Cancer.gov

El Instituto Nacional del Cáncer (NCI) anunció este mes una variedad de contribuciones que totalizan casi 1 millón de dólares para ayudar a desarrollar la investigación y programas para comprender y finalmente romper la División Digital que existe en muchas poblaciones minoritarias para el acceso y uso de la información sobre el cáncer disponible en la Internet. Las contribuciones son un esfuerzo del Servicio de Información sobre el Cáncer (CIS), dependiente de la NCI, para trabajar con grupos y organizaciones regionales para el control del cáncer para probar estrategias destinadas a aumentar las comunicaciones sobre el cáncer en comunidades deficientemente atendidas

132

Focal para-hisian atrial tachycardia with dual exits.  

PubMed

Focal atrial tachycardias (AT) in the right atrium (RA) tend to cluster around the crista terminalis, coronary sinus (CS) region, tricuspid annulus, and para-hisian region. In most cases, the AT focus can be identified by careful activation mapping, and completely eliminated by radiofrequency (RF) catheter ablation. However, RF ablation near the His bundle (HB) carries a risk of inadvertent damage to the atrioventricular (AV) conduction system. Here we describe a patient with an AT originating in the vicinity of the AV node, which was successfully ablated earlier from non-coronary aortic cusp (NCC), and recurred with an exit from para-hisian location. Respiratory excursions of the catheter were associated with migration to the area of HIs. This was successfully ablated during controlled apnoea, using 3D electroanatomic mapping. PMID:23993015

Lawrance Jesuraj, M; Sharada, K; Sridevi, C; Narasimhan, C

2013-01-01

133

Focal para-hisian atrial tachycardia with dual exits  

PubMed Central

Focal atrial tachycardias (AT) in the right atrium (RA) tend to cluster around the crista terminalis, coronary sinus (CS) region, tricuspid annulus, and para-hisian region. In most cases, the AT focus can be identified by careful activation mapping, and completely eliminated by radiofrequency (RF) catheter ablation. However, RF ablation near the His bundle (HB) carries a risk of inadvertent damage to the atrioventricular (AV) conduction system. Here we describe a patient with an AT originating in the vicinity of the AV node, which was successfully ablated earlier from non-coronary aortic cusp (NCC), and recurred with an exit from para-hisian location. Respiratory excursions of the catheter were associated with migration to the area of HIs. This was successfully ablated during controlled apnoea, using 3D electroanatomic mapping.

Lawrance Jesuraj, M.; Sharada, K.; Sridevi, C.; Narasimhan, C.

2013-01-01

134

Validation of the Escala de Inteligencia Wechsler Para Adultos  

Microsoft Academic Search

This study examined the comparability between the Wechsler Adult Intelligence Scale-Revised (WAIS-R) and its Spanish-language adaptation the Escala De Inteligencia Para Adultos (EIWA). Fifty Puerto Rican, bilingual examinees who showed equal language proficiency in English and Spanish using the Bilingual Syntax Measure II (BSM-II) were administered both intelligence tests.^ Results of this study showed a mean difference between the EIWA

Carlos Y Maldonado

1995-01-01

135

DYNA3D\\/ParaDyn Regression Test Suite Inventory  

Microsoft Academic Search

The following table constitutes an initial assessment of feature coverage across the regression test suite used for DYNA3D and ParaDyn. It documents the regression test suite at the time of production release 10.1 in September 2010. The columns of the table represent groupings of functionalities, e.g., material models. Each problem in the test suite is represented by a row in

Lin

2011-01-01

136

On Linear Differential Equations Involving a Para-Grassmann Variable  

NASA Astrophysics Data System (ADS)

As a first step towards a theory of differential equations involving para-Grassmann variables the linear equations with constant coefficients are discussed and solutions for equations of low order are given explicitly. A connection to n-generalized Fibonacci numbers is established. Several other classes of differential equations (systems of first order, equations with variable coefficients, nonlinear equations) are also considered and the analogies or differences to the usual (''bosonic'') differential equations discussed.

Mansour, Toufik; Schork, Matthias

2009-07-01

137

Utilização de hardware reconfigurável para acelerar a satisfação booleana  

Microsoft Academic Search

* Trabalho financiado com a bolsa da FCT-PRAXIS XXI\\/BD\\/21353\\/99 Resumo - Este artigo apresenta um estudo de possibilidade de aceleração da satisfação booleana com a ajuda do hardware reconfigurável. A satisfação booleana (SAT) é um problema importante que tem muitas aplicações em CAD e outras áreas. Neste artigo propomos uma técnica de desenvolvimento orientada a problema em geral para acelerar

Iouliia Skliarova; António B. Ferrari

2001-01-01

138

Microbial conversion of glucose to para-hydroxystyrene  

US Patent & Trademark Office Database

An in vivo method for the production of pHS via a recombinant host cell is disclosed. The host cell expresses at least one gene encoding a polypeptide having para-hydroxycinnamic acid decarboxylase activity in combination with either at least one gene encoding a polypeptide having tyrosine ammonia lyase activity or at least one gene encoding a polypeptide having phenylalanine ammonia lyase activity.

2007-06-12

139

Edukalibre: una herramienta para la creacion colaborativa de material didactico  

Microsoft Academic Search

El Software Libre, con sus caracter¶‡sticas y su particular modelo de desarrollo, ha permitido la creacion de un conjunto de metodolog¶‡as de trabajo en grupo que han resultado satisfactorias en gran cantidad diferentesambitos. En este sentido, el proyecto Edukalibre importa y adapta estas metodolog¶‡as para ser aplicadas en la creacion y man- tenimiento de documentacion en elambito de la educacion.

Diego Chaparro; Teofllo Romera

140

PARA-HYDROXYBENZOATE AS AN INTERMEDIATE IN THE ANAEROBIC TRANSFORMATION OF PHENOL TO BENZOATE  

EPA Science Inventory

Anaerobic phenol transformation was studied using a consortium which transformed phenol to benzoate without complete mineralization of benzoate. Products of monofluorophenol transformation indicate para-carboxylation. henol and benzoate were detected during para-hydroxybenzoate (...

141

A study of the valence shell electronic structure and photoionisation dynamics of para-dichlorobenzene and para-bromochlorobenzene  

NASA Astrophysics Data System (ADS)

The valence shell electronic structure and photoionisation dynamics of para-dichlorobenzene and para-bromochlorobenzene have been investigated both experimentally and theoretically. High resolution photoelectron spectra of the outer valence orbitals have been recorded with HeI radiation and the observed structure has been interpreted using calculated ionisation energies and spectral intensities. The theoretical predictions for the single-hole ionic states due to outer valence ionisation agree satisfactorily with the experimental results. Ionisation from the inner valence orbitals is strongly influenced by many-body effects and the with a particular orbital is spread amongst numerous satellites. Some of the photoelectron bands exhibit vibrational progressions and tentative assignments have been proposed. The photoionisation dynamics of the outer valence orbitals of para-dichlorobenzene have been investigated theoretically by using the continuum multiple scattering approach to calculate photoionisation partial cross-sections and photoelectron anisotropy parameters. The results show that ionisation from some of the orbitals is affected by the Cooper minimum associated with the chlorine atom. Synchrotron radiation has been used to record angle resolved photoelectron spectra of the entire valence shell, for photon energies between threshold and ˜100 eV, and these have allowed the corresponding experimental data to be derived. A comparison between the predicted and measured anisotropy parameters confirms the influence of the Cooper minimum in those orbitals related to the chlorine lone-pairs.

Powis, I.; Trofimov, A. B.; Bodzuk, I. L.; Holland, D. M. P.; Potts, A. W.; Karlsson, L.

2013-03-01

142

Opciones de cirugía para mujeres con CDIS o con cáncer de seno  

Cancer.gov

Folleto para mujeres con CDIS o con cáncer de seno que pueden operarse con cirugía. Esta guía explica los tipos de cirugía de seno, como la operación para preservar el seno y la mastectomía, y ayuda a las mujeres a decidir cuál cirugía es la mejor opción para ellas.

143

Consideraciones para el desarrollo de la creatividad y la enseñanza problémica en el aula  

Microsoft Academic Search

La “Metodología para estimular y desarrollar la creatividad técnica a través de la enseñanza del dibujo básico” ofrece un material docente contentivo con un conjunto de orientaciones e indicaciones que contribuya a estimular la creatividad técnica en la solución de problemas técnicos para los estudiantes que cursan carreras técnicas y como vía para la capacitación de los docentes. La misma

Angel Carvajal Castillo; María Elena Sierra Sandoval

2011-01-01

144

Opciones de cirugía para mujeres con CDIS o con cáncer de seno  

Cancer.gov

E-book para mujeres con CDIS o con cáncer de seno que pueden operarse con cirugía. Esta guía explica los tipos de cirugía de seno, como la operación para preservar el seno y la mastectomía, y ayuda a las mujeres a decidir cuál cirugía es la mejor opción para ellas.

145

LABORATORIO REMOTO PARA LA PROGRAMACIÓN DE ROBOTS INDUSTRIALES ABB EN LENGUAJE RAPID  

Microsoft Academic Search

El aprendizaje efectivo del lenguaje de programación para robots necesita de una constante realización de prácticas. Este trabajo describe la metodología llevada a cabo para conseguir el aprendizaje del lenguaje RAPID. Se ha desarrollado un sistema de aprendizaje para prácticas remotas y presenciales que emplea un robot IRB140 de ABB, un PLC con tarjeta Ethernet y servidor web, una cámara

A. ROSADO; R. SEGURA; G. RUIZ; J. MUÑOZ; R. MAGDALENA

146

Ortho-to-para ratio of interstellar heavy water  

NASA Astrophysics Data System (ADS)

Context. Despite the low elemental deuterium abundance in the Galaxy, enhanced molecular D/H ratios have been found in the environments of low-mass star-forming regions, and in particular the Class 0 protostar IRAS 16293-2422. Aims: The CHESS (Chemical HErschel Surveys of Star forming regions) key program aims to study the molecular complexity of the interstellar medium. The high sensitivity and spectral resolution of the Herschel/HIFI instrument provide a unique opportunity to observe the fundamental 11,1-00,0 transition of the ortho-D2O molecule, which is inaccessible from the ground, and determine the ortho-to-para D2O ratio. Methods: We detected the fundamental transition of the ortho-D2O molecule at 607.35 GHz towards IRAS 16293-2422. The line is seen in absorption with a line opacity of 0.62 ± 0.11 (1?). From the previous ground-based observations of the fundamental 11,0-10,1 transition of para-D2O seen in absorption at 316.80 GHz, we estimate a line opacity of 0.26 ± 0.05 (1?). Results: We show that the observed absorption is caused by the cold gas in the envelope of the protostar. Using these new observations, we estimate for the first time the ortho-to-para D2O ratio to be lower than 2.6 at a 3? level of uncertainty, which should be compared with the thermal equilibrium value of 2:1. Herschel is an ESA space observatory with science instruments provided by European-led principal Investigator consortia and with important participation from NASA.

Vastel, C.; Ceccarelli, C.; Caux, E.; Coutens, A.; Cernicharo, J.; Bottinelli, S.; Demyk, K.; Faure, A.; Wiesenfeld, L.; Scribano, Y.; Bacmann, A.; Hily-Blant, P.; Maret, S.; Walters, A.; Bergin, E. A.; Blake, G. A.; Castets, A.; Crimier, N.; Dominik, C.; Encrenaz, P.; Gérin, M.; Hennebelle, P.; Kahane, C.; Klotz, A.; Melnick, G.; Pagani, L.; Parise, B.; Schilke, P.; Wakelam, V.; Baudry, A.; Bell, T.; Benedettini, M.; Boogert, A.; Cabrit, S.; Caselli, P.; Codella, C.; Comito, C.; Falgarone, E.; Fuente, A.; Goldsmith, P. F.; Helmich, F.; Henning, T.; Herbst, E.; Jacq, T.; Kama, M.; Langer, W.; Lefloch, B.; Lis, D.; Lord, S.; Lorenzani, A.; Neufeld, D.; Nisini, B.; Pacheco, S.; Pearson, J.; Phillips, T.; Salez, M.; Saraceno, P.; Schuster, K.; Tielens, X.; van der Tak, F.; van der Wiel, M. H. D.; Viti, S.; Wyrowski, F.; Yorke, H.; Cais, P.; Krieg, J. M.; Olberg, M.; Ravera, L.

2010-10-01

147

Amazon Land Wars in the South of Para  

NASA Technical Reports Server (NTRS)

The South of Para, located in the heart of the Brazilian Amazon, has become notorious for violent land struggle. Although land conflict has a long history in Brazil, and today impacts many parts of the country, violence is most severe and persistent here. The purpose of this article is to examine why. Specifically, we consider how a particular Amazonian place, the so-called South of Para has come to be known as Brazil's most dangerous badland. We begin by considering the predominant literature, which attributes land conflict to the frontier expansion process with intensified struggle emerging in the face of rising property values and demand for private property associated with capitalist development. From this discussion, we distill a concept of the frontier, based on notions of property rights evolution and locational rents. We then empirically test the persistence of place-based violence in the region, and assess the frontier movement through an analysis of transportation costs. The findings from the analyses indicate that the prevalent theorization of frontier violence in Amazonia does little to explain its persistent and pervasive nature in the South of Para. To fill this gap in understanding, we develop an explanation based the geographic conception of place, and we use contentious politics theory heuristically to elucidate the ways in which general processes interact with place specific history to engender a landscape of violence. In so doing, we focus on environmental, cognitive, and relational mechanisms (and implicated structures), and attempt to deploy them in an explanatory framework that allows direct observation of the accumulating layers of the region's tragic history. We end by placing our discussion within a political ecological context, and consider the implications of the Amazon Land War for the environment.

Simmons, Cynthia S.; Walker, Robert T.; Arima, Eugenio Y.; Aldrich, Stephen P.; Caldas, Marcellus M.

2007-01-01

148

ORTHO-PARA SELECTION RULES IN THE GAS-PHASE CHEMISTRY OF INTERSTELLAR AMMONIA  

SciTech Connect

The ortho-para chemistry of ammonia in the cold interstellar medium is investigated using a gas-phase chemical network. Branching ratios for the primary reaction chain involved in the formation and destruction of ortho- and para-NH{sub 3} were derived using angular momentum rules based on the conservation of the nuclear spin. We show that the 'anomalous' ortho-to-para ratio of ammonia ({approx}0.7) observed in various interstellar regions is in fact consistent with nuclear spin selection rules in a para-enriched H{sub 2} gas. This ratio is found to be independent of temperature in the range 5-30 K. We also predict an ortho-to-para ratio of {approx}2.3 for NH{sub 2}. We conclude that a low ortho-to-para ratio of H{sub 2} naturally drives the ortho-to-para ratios of nitrogen hydrides below the statistical values.

Faure, A.; Hily-Blant, P.; Le Gal, R.; Rist, C. [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d'Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble F-38041 (France); Pineau des Forets, G., E-mail: afaure@obs.ujf-grenoble.fr [Institut d'Astrophysique Spatiale, Universite Paris-Orsay and CNRS, Orsay (France)

2013-06-10

149

Persistent molecular superfluid response in doped para-hydrogen clusters.  

PubMed

Direct observation of superfluid response in para-hydrogen (p-H(2)) remains a challenge because of the need for a probe that would not induce localization and a resultant reduction in superfluid fraction. Earlier work [H. Li, R. J. Le Roy, P.-N. Roy, and A. R. W. McKellar, Phys. Rev. Lett. 105, 133401 (2010)] has shown that carbon dioxide can probe the effective inertia of p-H(2) although larger clusters show a lower superfluid response due to localization. It is shown here that the lighter carbon monoxide probe molecule allows one to measure the effective inertia of p-H(2) clusters while maintaining a maximum superfluid response with respect to dopant rotation. Microwave spectroscopy and a theoretical analysis based on Feynman path-integral simulations are used to support this conclusion. PMID:23004599

Raston, P L; Jäger, W; Li, H; Le Roy, R J; Roy, P-N

2012-06-22

150

Persistent Molecular Superfluid Response in Doped Para-Hydrogen Clusters  

NASA Astrophysics Data System (ADS)

Direct observation of superfluid response in para-hydrogen (p-H2) remains a challenge because of the need for a probe that would not induce localization and a resultant reduction in superfluid fraction. Earlier work [H. Li, R. J. Le Roy, P.-N. Roy, and A. R. W. McKellar, Phys. Rev. Lett.PRLTAO0031-9007 105, 133401 (2010)10.1103/PhysRevLett.105.133401] has shown that carbon dioxide can probe the effective inertia of p-H2 although larger clusters show a lower superfluid response due to localization. It is shown here that the lighter carbon monoxide probe molecule allows one to measure the effective inertia of p-H2 clusters while maintaining a maximum superfluid response with respect to dopant rotation. Microwave spectroscopy and a theoretical analysis based on Feynman path-integral simulations are used to support this conclusion.

Raston, P. L.; Jäger, W.; Li, H.; Le Roy, R. J.; Roy, P.-N.

2012-06-01

151

ParaText : scalable text analysis and visualization.  

SciTech Connect

Automated analysis of unstructured text documents (e.g., web pages, newswire articles, research publications, business reports) is a key capability for solving important problems in areas including decision making, risk assessment, social network analysis, intelligence analysis, scholarly research and others. However, as data sizes continue to grow in these areas, scalable processing, modeling, and semantic analysis of text collections becomes essential. In this paper, we present the ParaText text analysis engine, a distributed memory software framework for processing, modeling, and analyzing collections of unstructured text documents. Results on several document collections using hundreds of processors are presented to illustrate the exibility, extensibility, and scalability of the the entire process of text modeling from raw data ingestion to application analysis.

Dunlavy, Daniel M.; Stanton, Eric T.; Shead, Timothy M.

2010-07-01

152

Technique to match mantle and para-aortic fields  

SciTech Connect

A technique is described to match the mantle and para-aortic fields used in treatment of Hodgkin's disease, when the patient is treated alternately in supine and prone position. The approach is based on referencing the field edges to a point close to the vertebral column, where uncontrolled motion is minimal and where accurate matching is particularly important. Fiducial surface points are established in the simulation process to accomplish the objective. Dose distributions have been measured to study the combined effect of divergence differences, changes in body angulation and setup errors. Even with the most careful technique, the use of small cord blocks of 50% transmission is an advisable precaution for the posterior fields.

Lutz, W.R.; Larsen, R.D.

1983-11-01

153

Sponges, Tubules and Modulated Phases of Para-Antinematic Membranes  

NASA Astrophysics Data System (ADS)

We theoretically analyze the behavior of membranes presenting a nematic susceptibility, induced by the presence of anisotropic phospholipids having a quadrupolar nematic symmetry. This kind of anisotropic phospholipids is either naturally found in some biological membranes, or can be chemically tailored by linking pairs of single surfactants at the level of their polar heads, giving rise to so-called “gemini” surfactants. We predict that such membranes can acquire a non-zero paranematic order induced by the membrane curvature, which in turn produces curvature instabilities. We call the resulting paranematic order para-antinematic, since it is opposite on opposite sides of the membrane. We find phase transitions toward sponges (L3), tubules, or modulated “egg-carton” phases.

Fournier, J. B.; Galatola, P.

1997-10-01

154

Cosmoeducação: uma proposta para o ensino de astronomia  

NASA Astrophysics Data System (ADS)

Entende-se por cosmoeducação o desenvolvimento vivencial da unidade homem-cosmo. Este conceito é norteado pela psicologia transpessoal, que estuda o ser humano em sua totalidade, onde suas relações ecológicas e cósmicas são de grande importância. Constata-se uma necessidade latente no ser humano moderno em resgatar uma relação holística com o Universo. Neste trabalho exploramos meios de cultivar a consciência de que o ser humano constitui parte integrante do cosmo e se relaciona com este com o objetivo de promover em si uma percepção ambiental mais ampla. Nossa hipótese de trabalho inicial foi que o ensino de conteúdos básicos em astronomia realizado através de uma abordagem holística, que incorpore práticas vivenciais correlacionadas àqueles conteúdos, pode despertar no indivíduo sua identidade cósmica. O método que utilizamos é o fenomenológico e o universo desta pesquisa é um grupo de estudantes da disciplina de Astronomia (Curso de Licenciatura em Geografia/UFRN), onde realizamos observação participante, entrevistas, depoimentos e as práticas vivenciais mencionadas. Neste caso estamos desenvolvendo e adaptando exercícios de algumas técnicas terapêuticas de psicologia transpessoal, que um de nós (LALM) tem aplicado no contexto clínico, para trabalhar aspectos cognitivos envolvidos naquele processo de conscientização cósmica. Resultados parciais claramente referendam a hipótese inicial. Um resultado a destacar é fruto de uma dinâmica de representação corporal interiorizada do eclipse lunar, envolvendo um pequeno grupo daqueles estudantes, na qual conteúdos míticos afloraram de maneira espontânea e contundente para todos, sugerindo ressonância, ou pelo menos isomorfismo, entre o macro e o microcosmo. Este e outros resultados são discutidos em detalhe neste trabalho. (PPGECNM/UFRN; PRONEX/FINEP; NUPA/USP; Temáticos/FAPESP).

Medeiros, L. A. L.; Jafelice, L. C.

2003-08-01

155

A conversation robot using head gesture recognition as para-linguistic information  

Microsoft Academic Search

A conversation robot that recognizes user's head gestures and uses its results as para-linguistic information is developed. In the conversation, humans exchange linguistic information, which can be obtained by transcription of the utterance, and para-linguistic information, which helps the transmission of linguistic information. Para-linguistic information brings a nuance that cannot be transmitted by linguistic information, and the natural and effective

Shinya Fujie; Yasushi Ejiri; Kei Nakajima; Yosuke Matsusaka; Tetsunori Kobayashi

2004-01-01

156

Ammonium-excreting Azospirillum sp. become intracellularly established in maize ( Zea mays ) para-nodules  

Microsoft Academic Search

Maize seedlings develop nodule-like tumour knots (para-nodules) along primary roots when treated with the auxin 2,4-dichlor-phenoxy-acetic acid (2,4-D). Inoculated NH4+-excreting Azospirillum brasilense cells were shown to colonize these tumours, mostly intracellularly, promoting a high level of N2 fixation when microaerophilic conditions were imposed. The nitrogenase activity inside the para-nodules was less sensitive to free O2 than in non-para-nodulating roots. Both

C. Christiansen-Weniger; Jos Vanderleyden

1994-01-01

157

EQUAÇÕES DE VOLUME PARA A FLORESTA NACIONAL DO TAPAJÓS (Volume equations for the Tapajós National Forest)  

Microsoft Academic Search

Com o objetivo de atender a demanda de informações acerca de relações quantitativas para a Floresta Nacional do Tapajós, Estado do Pará, selecionaram-se equações de volume para andiroba (Carapa guianensis), abiurana (diversos gêneros), jutaí-açu (Hymenaea courbaril), jarana (Holopyxidium jarana), ucuuba- da-terra-firme (Virola sp), taxi-vermelho (Sclerolobium chrysophyllum), maçaranduba (Manilkara huberi), além de equações abrangentes, para qualquer espécie. Testaram-se 16 equações, nove

José Natalino Macedo Silva

158

CARACTERÍSTICAS PRODUTIVAS E QUALITATIVAS DE HÍBRIDOS DE MILHO PARA PRODUÇÃO DE SILAGEM  

Microsoft Academic Search

RESUMO - A avaliação dos genótipos de milho disponíveis no mercado é de grande interesse tanto para produtores como para pesquisadores da área de produção animal e vegetal. Nesse sentido, objetivou-se avaliar o potencial produtivo e qualitativo de híbri- dos de milho para a produção de silagem. Os tratamentos foram constituídos por seis híbridos de milho: DKB-215, DKB-344, C-747, AS-32,

RENIUS MELLO; JOSÉ LAERTE NÖRNBERG; MARTA GOMES DA ROCHA; DIEGO BITENCOURT DE DAVID

159

Nueva opción de tratamiento para mujeres jóvenes con cáncer de seno sensible a las hormonas  

Cancer.gov

Un fármaco usado para el tratamiento del cáncer de seno (mama), conocido como exemestano, es más eficaz que tamoxifeno, un fármaco preventivo de uso común para el cáncer de seno, en la prevención de la recidiva del cáncer de seno en mujeres jóvenes que también reciben tratamiento posoperativo para suprimir el funcionamiento ovárico. Los resultados de este estudio se presentaron en mujeres que tenían un tipo de cáncer de seno en estadio inicial sensible al tratamiento hormonal.

160

The Ratio of Ortho- to Para-H2 in Photodissociation Regions  

NASA Technical Reports Server (NTRS)

We discuss the ratio of ortho- to para-H2 in photodissociation regions (PDRs). We draw attention to an apparent confusion in the literature between the ortho-to-para ratio of molecules in FUV-pumped vibrationally excited states and the total H2 ortho-to-para abundance ratio. These ratios are not the same because the process of FUV pumping of fluorescent H2 emission in PDRs occurs via optically thick absorption lines. Thus gas with an equilibrium ratio of ortho- to para-H2 equal to 3 will yield FUV-pumped vibrationally excited ortho-to-para ratios smaller than 3, because the ortho-H2 pumping rates are preferentially reduced by optical depth effects. Indeed, if the ortho and para pumping lines are on the "square root" part of the curve of growth, then the expected ratio of ortho and para vibrational line strengths is 3(sup 1/2) approximately 1.7, close to the typically observed value. Thus, contrary to what has sometimes been stated in the literature, most previous measurements of the ratio of ortho- to para-H2 in vibrationally excited states are entirely consistent with a total ortho-to-para ratio of 3, the equilibrium value for temperatures greater than 200 K. We present an analysis and several detailed models that illustrate the relationship between the total ratios of ortho- to para-H2 and the vibrationally excited ortho-to-para ratios in PDRs. Recent Infrared Space Observatory measurements of pure rotational and vibrational H2 emissions from the PDR in the star-forming region S140 provide strong observational support for our conclusions.

Sternberg, Amiel; Neufeld, David A.

1999-01-01

161

Uninfected Para-Anastomotic Aneurysms after Infrarenal Aortic Grafting  

PubMed Central

Purpose This single-institution retrospective review examines the management of uninfected para-anastomotic aneurysms of the abdominal aorta (PAAA), developed after infrarenal grafting. Materials and Methods From October 1979 to November 2005, 31 PAAA were observed in our Department. Twenty-six uninfected PAAA of degenerative etiology, including 24 false and 2 true aneurysms, were candidates for intervention and retrospectively included in our database for management and outcome evaluation. Six (23%) patients were treated as emergencies. Surgery included tube graft interposition (n = 12), new reconstruction (n = 8), and graft removal with extra-anatomic bypass (n = 3). Endovascular management (n = 3) consisted of free-flow tube endografts. Results The mortality rate among the elective and emergency cases was 5% and 66.6%, respectively (p = 0.005). The morbidity rate in elective cases was 57.8%, whereas 75% in emergency cases (p = 0.99). The survival rate during the follow-up was significantly higher for elective cases than for emergency cases. Conclusion Uninfected PAAA is a late complication of aortic grafting, tends to evolve silently and is difficult to diagnose. The prevalence is underestimated and increases with time since surgery. The mortality rate is higher among patients treated as an emergency than among patients who undergo elective surgery, therefore, elective treatment and aggressive management in the case of pseudoaneurysm are the keys to obtain a good outcome. Endovascular treatment could reduce mortality. Patients who undergo infrarenal aortic grafting require life-long surveillance after surgery.

Nano, Giovanni; Cusmai, Francesco; Ramponi, Fabio; Stegher, Silvia; Dell'Aglio, Daniela; Malacrida, Giovanni; Tealdi, Domenico G.

2009-01-01

162

Evidence for para dechlorination of polychlorobiphenyls by methanogenic bacteria  

SciTech Connect

When microorganisms eluted from upper Hudson River sediment were cultured without any substrate except polychlorobiphenyl (PCB)-free Hudson River sediment, methane formation was the terminal step of the anaerobic food chain. In sediments containing Aroclor 1242, addition of eubacterium-inhibiting antibiotics, which should have directly inhibited fermentative bacteria and thereby should have indirectly inhibited methanogens, resulted in no dechlorination activity or methane production. However, when substrates for methanogenic bacteria were provided along with the antibiotics (to free the methanogens from dependence on eubacteria), concomitant methane production and dechlorination of PCBs were observed. The dechlorination of Aroclor 1242 was from the para positions, a pattern distinctly different from, and more limited than, the pattern observed with untreated or pasteurized inocula. Both methane production and dechlorination in cultures amended with antibiotics plus methanogenic substrates were inhibited by 2-bromoethanesulfonic acid. These results suggest that the methanogenic bacteria are among the physiological groups capable of anaerobic dechlorination of PCBs, but that the dechlorination observed with methanogenic bacteria is less extensive than the dechlorination observed with more complex anaerobic consortia. 27 refs., 5 figs., 1 tab.

Ye, D.; Quensen, J.F.; Tiedje, J.M. [Michigan State Univ., East Lansing, MI (United States)] [and others

1995-06-01

163

A Para-Canalicular Abscess Resembling an Inflamed Chalazion  

PubMed Central

Background. Lacrimal infections by Actinomyces are rare and commonly misdiagnosed for long periods of time. They account for 2% of all lacrimal diseases. Case Report. We report a case of a 70-year-old female patient suffering from a para-canalicular abscess in the medial canthus of the left eye, beside the lower punctum lacrimale, resembling a chalazion. Purulence exited from the punctum lacrimale due to inflammation of the inferior canaliculus (canaliculitis). When pressure was applied to the mass, a second exit of purulence was also observed under the palpebral conjunctiva below the lacrimal caruncle. A surgical excision was performed followed by administration of local antibiotic therapy. The histopathological examination of the extracted mass revealed the existence of actinomycosis. Conclusion. Persistent or recurrent infections and lumps of the eyelids should be thoroughly investigated. Actinomyces as a causative agent should be considered. Differential diagnosis is broad and should include canaliculitis, chalazion, and multiple types of neoplasias. For this reason, in nonconclusive cases, a histopathological examination should be performed.

Almaliotis, Diamantis; Nakos, Elias; Siempis, Thomas; Koletsa, Triantafyllia; Kostopoulos, Ioannis; Chatzipantazi, Maria; Karampatakis, Vasileios

2013-01-01

164

New gene responsible for para-aminobenzoate biosynthesis.  

PubMed

Folate is an essential cofactor in all living cells for one-carbon transfer reactions. para-Aminobenzoate (pABA), a building block of folate, is usually derived from chorismate in the shikimate pathway by reactions of aminodeoxychorismate synthase (PabA and -B) and 4-amino-4-deoxychorismate lyase (PabC). We previously suggested that an alternative pathway for pABA biosynthesis would operate in some microorganisms such as Lactobacillus fermentum and Nitrosomonas europaea since these bacteria showed a prototrophic phenotype to pABA despite the fact that there are no orthologs of pabA, -B, and -C in their genome databases. In this study, a gene of unknown function, NE1434, was obtained from N. europaea by shotgun cloning using a pABA-auxotrophic Escherichia coli mutant (?pabABC) as a host. A tracer experiment using [U-(13)C6]glucose suggested that pABA was de novo synthesized in the transformant. An E. coli ?pabABC?aroB mutant carrying the NE1434 gene exhibited a prototrophic phenotype to pABA, suggesting that compounds in the shikimate pathway including chorismate were not utilized as substrates by NE1434. Moreover, the CT610 gene, an ortholog of NE1434 located in the folate biosynthetic gene cluster in Chlamydia trachomatis, also complemented pABA-auxotrophic E. coli mutants. Taken together, these results suggest that NE1434 and CT610 participate in pABA biosynthesis. PMID:23972426

Satoh, Yasuharu; Kuratsu, Masahiro; Kobayashi, Daiki; Dairi, Tohru

2014-02-01

165

Para-dichlorobenzene toxicity - a review of potential neurotoxic manifestations  

PubMed Central

Background: Para-dichlorobenzene (PDCB) is an active ingredient of mothballs, deodorizers and fumigants. Due to the easy availability of this chemical, there is a considerable risk for accidental or intentional toxic exposure. Recently, multiple cases of PDCB toxicity due to mothball ingestion were reported. PDCB toxicity can affect multiple organ systems including liver, kidneys, skin, lung and the central nervous system (CNS). CNS toxicity often results in leukoencephalopathy and heterogeneous neurological manifestations. Objectives: The objective of this study was to illustrate the clinical presentation, imaging findings, diagnosis and management of PDCB toxicity. Methods: We carried out a literature review of the pharmacological and toxicological properties of PDCB. Conclusions: PDCB and other aromatic hydrocarbons are capable of CNS tissue damage and in promoting functional neurological decline. While very little is currently known about prevalence of PDCB addiction, it cannot be ruled out that its illicit use among young people is under-recognized. The number of cases of PDCB toxicity might also rise due to the increasing industrial and domestic use of this chemical.

Dubey, Divyanshu; Sharma, Vibhash D.; Pass, Steven E.; Sawhney, Anshudha

2014-01-01

166

Anise oil as para-methoxyamphetamine (PMA) precursor.  

PubMed

These days, MDMA is one of the most popular drugs of abuse. Due to its illegality, MDMA and its chemical precursors are watched by governmental organizations in many countries. To avoid conflicts with legal instances, underground chemists have tried to market several new unregulated amphetamine analogues, such as 4-MTA. Para-methoxyamphetamine (PMA), on the other hand, is regulated by law but its precursors are easily obtained since they are cheap and unwatched. This article presents such a case, namely the large scale synthesis of PMA using anethole, a main constituent of anise oil, as precursor. Anethole has been converted to its phenyl acetone analogue via peracid oxidation, while PMA itself has been synthesized using this ketone as precursor in the Leuckart synthesis. The synthesis of PMA using anethole as starting product has been investigated applying GC/MS and GC-HSPME/MS techniques, hereby discovering new specific (4-methoxyphenol) and already identified synthesis impurities (4-methyl-5-(4-methoxyphenyl)pyrimidine, N-(beta-4-methoxyphenylisopropyl)-4-methoxybenzyl methyl ketimine, 1-(4-methoxyphenyl)-N-(2-(4-methoxyphenyl)-1-methylethyl-2-propanamine, 1-(4-methoxyphenyl)-N-methyl-N-(2-(4-methoxyphenyl)-1-methylethyl-2-propanamine, N-(beta-4-methoxyphenylisopropyl)-4-methoxybenzaldimine). The new impurity 4-methoxyphenol is specific for the application of a peracid oxidation method where anethole is used as precursor. PMID:12742705

Waumans, Dieter; Bruneel, Noël; Tytgat, Jan

2003-04-23

167

Effect of thermal aging on the defectiveness of ultrastrong para-aromatic armos and SVM fibres  

Microsoft Academic Search

The change in the defectiveness of ultrastrong para-aromatic Armos and SVM fibres during thermal aging in air was investigated based on the scale dependences and coefficients of variation of the breaking characteristics: strength, elongation, and strain energy at break. The increase in the defectiveness of ultrastrong para-aromatic fibres during thermal aging can be more objectively assessed by the change in

K. E. Perepelkin; S. A. Baranova; E. Yu. Gurova

1995-01-01

168

Development of polymorphic microsatellite markers for the livebearing fish Poecilia parae  

Microsoft Academic Search

We developed 16 novel polymorphic tetranucleotide microsatellite markers for Poecilia parae, a livebearing fish used in evolutionary studies because of its Y-linked colour and size polymorphism. A set of 199 clones was sequenced out of an enriched genomic library, and we achieved an enrichment efficiency of nearly 80%. Primers were designed for 16 pure repeats, and 59 P. parae were

ALEXANDER NATER; MICHAEL KRÜTZEN; ANNA K. LINDHOLM

2008-01-01

169

WebAPSEE: Um Ambiente Livre e Flexível Para Gerência de Processos de Software1  

Microsoft Academic Search

This paper describes an open-source Flexible Environment for Software Development Process Management. Thus, it presents a process enactment scenario used by the NetBeans project in order show the main functionalities provided by the cited environment. Resumo. Este artigo descreve um Ambiente Flexível para Gerência de Processos de desenvolvimento de Software baseado em Software Livre. Para ilustrar as funcionalidades fornecidas pelo

Adailton Lima; Breno França; Heribert Schlebbe; Rodrigo Quites Reis; Carla Lima Reis

170

Thermal Structure and Para Hydrogen Fraction on the Outer Planets from VoyagerIRIS Measurements  

Microsoft Academic Search

Voyagerinfrared spectra from Jupiter, Saturn, Uranus, and Neptune are used to infer latitude-height cross sections of temperature and para hydrogen fraction. A new inversion algorithm is developed that simultaneously retrieves both quantities. It uses all portions of the spectra containing information about temperature and para fraction and not influenced by other properties, such as cloud opacity. The sensitivity of spectra

Barney J. Conrath; Peter J. Gierasch; Eugene A. Ustinov

1998-01-01

171

Sudan azo dyes and Para Red degradation by prevalent bacteria of the human gastrointestinal tract  

Microsoft Academic Search

Sudan azo dyes have genotoxic effects and ingestion of food products contaminated with Sudan I, II, III, IV, and Para Red could lead to exposure in the human gastrointestinal tract. In this study, we examined thirty-five prevalent species of human intestinal bacteria to evaluate their capacity to degrade Sudan dyes and Para Red. Among these tested bacterial strains, 23, 13,

Haiyan Xu; Thomas M. Heinze; Donald D. Paine; Carl E. Cerniglia; Huizhong Chen

2010-01-01

172

PERSPECTIVAS METODOLÓGICAS PARA LA INVESTIGACIÓN DENTRO DEL AULA DE L2  

Microsoft Academic Search

Dicen Larsen- Freeman y Long (1991) que las premisas básicas para un experimento son que todos los factores excepto uno sean constantes para poder comprobar el efecto de ese factor sobre el fenómeno que se inves- tiga, y que se cuente con dos criterios esenciales: primero, que haya al me- nos dos grupos incluidos en el estudio, uno de control

Guadalupe Ruiz Fajardo

1991-01-01

173

[The place of para-aortic lymphadenectomy in gynaecological malignancies. An old debate].  

PubMed

There is a lack of prospective randomized trial and scientific evidence for the use of para-aortic lymphadenectomy in gynaecological malignancies. This results in variations between countries for its utility. Based on the recommandations of the French Institute of Cancer (INCa), we open the debate of the place of para-aortic lymphadenectomy. PMID:24793624

Philippe, Anne-Cécile; Dauplat, Jacques; Martinez, Alejandra; Canis, Michel; Bourdel, Nicolas; Ferron, Gwenaël; Pomel, Christophe

2014-04-01

174

Para-nitrobenzyl esterases with enhanced activity in aqueous and nonaqueous media  

DOEpatents

A method is disclosed for isolating and identifying modified para-nitrobenzyl esterases which exhibit improved stability and/or esterase hydrolysis activity toward selected substrates and under selected reaction conditions relative to the unmodified para-nitrobenzyl esterase. The method involves preparing a library of modified para-nitrobenzyl esterase nucleic acid segments (genes) which have nucleotide sequences that differ from the nucleic acid segment which encodes for unmodified para-nitrobenzyl esterase. The library of modified para-nitrobenzyl nucleic acid segments is expressed to provide a plurality of modified enzymes. The clones expressing modified enzymes are then screened to identify which enzymes have improved esterase activity by measuring the ability of the enzymes to hydrolyze the selected substrate under the selected reaction conditions. Specific modified para-nitrobenzyl esterases are disclosed which have improved stability and/or ester hydrolysis activity in aqueous or aqueous-organic media relative to the stability and/or ester hydrolysis activity of unmodified naturally occurring para-nitrobenzyl esterase. 43 figs.

Arnold, F.H.; Moore, J.C.

1999-05-25

175

Para-nitrobenzyl esterases with enhanced activity in aqueous and nonaqueous media  

DOEpatents

A method is disclosed for isolating and identifying modified para-nitrobenzyl esterases. These enzymes exhibit improved stability and/or esterase hydrolysis activity toward selected substrates and under selected reaction conditions relative to the unmodified para-nitrobenzyl esterase. The method involves preparing a library of modified para-nitrobenzyl esterase nucleic acid segments (genes) which have nucleotide sequences that differ from the nucleic acid segment which encodes for unmodified para-nitrobenzyl esterase. The library of modified para-nitrobenzyl nucleic acid segments is expressed to provide a plurality of modified enzymes. The clones expressing modified enzymes are then screened to identify which enzymes have improved esterase activity by measuring the ability of the enzymes to hydrolyze the selected substrate under the selected reaction conditions. Specific modified para-nitrobenzyl esterases are disclosed which have improved stability and/or ester hydrolysis activity in aqueous or aqueous-organic media relative to the stability and/or ester hydrolysis activity of unmodified naturally occurring para-nitrobenzyl esterase. 43 figs.

Arnold, F.H.; Moore, J.C.

1998-04-21

176

Sudan azo dyes and Para Red degradation by prevalent bacteria of the human gastrointestinal tract.  

PubMed

Sudan azo dyes have genotoxic effects and ingestion of food products contaminated with Sudan I, II, III, IV, and Para Red could lead to exposure in the human gastrointestinal tract. In this study, we examined thirty-five prevalent species of human intestinal bacteria to evaluate their capacity to degrade Sudan dyes and Para Red. Among these tested bacterial strains, 23, 13, 33, 30, and 29 out of 35 species tested were able to reduce Sudan I, II, III, IV, and Para Red, respectively, to some extent. Bifidobacterium infantis, Clostridium indolis, Enterococcus faecalis, Lactobacillus rhamnosus, and Ruminococcus obeum were able to reduce completely all four tested Sudan dyes and Para Red. Escherichia coli and Peptostreptococcus magnus were the only two strains that were not able to reduce any of the tested Sudan dyes and Para Red to any significant extent. Metabolites of the reduction of the tested Sudan dyes and Para Red by E. faecalis were isolated and identified by HPLC and LC/ESI-MS analyses and compared with authentic standards. Thus it appears that the ability to reduce Sudan dyes and Para Red except Sudan II is common among bacteria in the human colon. PMID:19580882

Xu, Haiyan; Heinze, Thomas M; Paine, Donald D; Cerniglia, Carl E; Chen, Huizhong

2010-04-01

177

Um enfoque antropológico para o ensino de astronomia no nível médio  

NASA Astrophysics Data System (ADS)

Há uma enorme carência de materiais didático-pedagógicos em astronomia para professores do ensino médio, sobretudo materiais que explorem também aspectos humanísticos. A origem do Universo é um bom exemplo desta constatação central. Embora tal origem teve explicações culturais diversas, os professores não têm informações sobre isso e muito menos material que trabalhe diferentes visões de mundo e treinamento que os capacite a abordá-las devidamente. Conseqüentemente o ensino de astronomia costuma ser tecnicista e dissociado do aspecto humano que alimenta o grande interesse e curiosidade que esses temas despertam. Aqui apresentamos propostas visando contribuir para reverter esse quadro e trabalhamos distintas visões de Universo: espontâneas, autóctones e científicas. Desenvolvemos práticas, materiais instrucionais e textos para viabilizar a adoção de um enfoque antropológico para o ensino de astronomia no nível médio, no qual as culturas humanística e científica sejam integradas de uma maneira contextualizada e eficaz para aquele ensino. Estas propostas foram aplicadas em um curso de treinamento para professores da rede pública de diferentes disciplinas. A receptividade dos professores à abordagem proposta e os resultados alcançados foram muito estimulantes. Destes, destacamos: produção de roteiros de atividades; desenvolvimento de práticas didático-pedagógicas específicas (e.g., encenação de mitos; dança primordial guarani; "criação" de constelações e interpretações pluriculturais; etc.); e sugestões concretas para a efetiva realização de um ensino interdisciplinar contextualizado, onde questões cosmogônicas servem de mote para iniciar tal ensino. Discutimos estes resultados e como o enfoque adotado pode instrumentalizar os professores para leituras de mundo que incluem naturalmente aspectos culturais, sociais e históricos associados aos temas estudados. (PPGECNM/UFRN; PRONEX/FINEP; NUPA/USP; Temáticos/FAPESP)

Costa, G. B.; Jafelice, L. C.

2003-08-01

178

Descripción de la zona de alta difusión en un modelo bidimensional para hojas de corriente  

NASA Astrophysics Data System (ADS)

Los modelos bidimensionales para describir hojas de corriente de alta simetría no suministran una descripción detallada de las regiones donde la difusión es considerablemente importante. Tal es el caso de los modelos desarrollados en la década del '60 por Sweet, Parker, Petschek y Sonnerup. En esta comunicación presentamos una solución de las ecuaciones MHD en el entorno del origen, construyendo series bidimensionales para todas las magnitudes físicas involucradas. Valiéndonos de la alta simetría y de las características del problema, logramos reducir el número de coeficientes a calcular. Utilizamos un programa autoconsistente para extender el cálculo a regiones vecinas con difusión moderada o despreciable.

Montero, M. F.; Paola, C. A.; Platzeck, A. M.

179

Measurement of the formaldehyde ortho to para ratio in three molecular clouds  

NASA Technical Reports Server (NTRS)

Observations of ortho and para H2CO in two types of clouds, a warm cloud (Orion A) and two cold clouds (L183 and TMC1), are presented. The ortho to para ratio in Orion deduced from the H2(C-13)O data is about three, while that for TMC1 is about one and that for L183 is 1-2. The former value is in agreement with the value calculated from chemical models of ortho and para H2CO production. The values for the cold clouds are consistent with thermal equilibrium at a temperature slightly smaller than 10 K.

Kahane, C.; Lucas, R.; Frerking, M. A.; Langer, W. D.; Encrenaz, P.

1984-01-01

180

Triebel-Lizorkin Spaces of Para-Accretive Type and a  Tb Theorem  

Microsoft Academic Search

In this article, we use a discrete Calderón-type reproducing formula and Plancherel-Pôlya-type inequality associated to a\\u000a para-accretive function to characterize the Triebel-Lizorkin spaces of para-accretive type \\u000a \\u000a , which reduces to the classical Triebel-Lizorkin spaces when the para-accretive function is constant. Moreover, we give a\\u000a necessary and sufficient condition for the \\u000a \\u000a boundedness of paraproduct operators. From this, we show that a

Chin-Cheng Lin; Kunchuan Wang

2009-01-01

181

Endovascular Treatment of a Ruptured Para-Anastomotic Aneurysm of the Abdominal Aorta  

SciTech Connect

We report a case of a ruptured para-anastomotic aortic aneurysm treated with implantation of a bifurcated stent-graft. A 72-year-old patient, who had undergone aortobifemoral bypass for aortoiliac occlusive disease 16 years ago, presented with a ruptured para-anastomotic aortic aneurysm. A bifurcated stent-graft was successfully deployed into the old bifurcated graft. This is the first report of a bifurcated stent-graft being placed through an 'end-to-side' anastomosed old aortobifemoral graft. Endovascular treatment of ruptured para-anastomotic aortic aneurysms can be accomplished successfully, avoiding open surgery which is associated with increased mortality and morbidity.

Sfyroeras, Giorgos S.; Lioupis, Christos, E-mail: lioupisC@vodafone.net.gr; Bessias, Nikolaos; Maras, Dimitris [Red Cross Hospital of Athens, Department of Vascular Surgery (Greece); Pomoni, Maria [Red Cross Hospital of Athens, Department of Radiology (Greece); Andrikopoulos, Vassilios [Red Cross Hospital of Athens, Department of Vascular Surgery (Greece)

2008-07-15

182

Contextual Factors that Foster or Inhibit Para-Teacher Professional Development: The Case of an Indian, Non-Governmental Organization  

ERIC Educational Resources Information Center

The appointment of para-professionals to overcome skill shortages and/or make efficient use of expensive resources is well established in both developing and developed countries. The present research concerns para-teachers in India. The literature on para-teachers is dominated by training for special needs settings, largely in developed societies.…

Raval, Harini; McKenney, Susan; Pieters, Jules

2012-01-01

183

Investigation of para-sulfonatocalix[n]arenes [n = 6, 8] as potential chelates for (230)U.  

PubMed

Literature reports of the efficacy of para-sulfonatocalix[6]- and calix[8]-arenes as U(vi) complexants indicated that they might be useful for in vivo chelation of the novel therapeutic alpha-emitter (230)U. We have studied the complexation of U(vi) with para-sulfonatocalix[6]arene and para-sulfonatocalix[8]arene by time resolved laser induced fluorescence spectroscopy and using competition methods with Chelex resin and 4-(2-pyridylazo)resorcinol in simplified and in biological media. New thermodynamic parameters describing the stability of U(vi)-para-sulfonatocalix[n]arene [n = 6, 8] complexes were obtained. Although the interactions are strong, the complexes do not exhibit sufficient stability to compete with carbonate ions and serum proteins for complexation of U(vi) under physiological conditions. PMID:20104364

Montavon, Gilles; Repinc, Urska; Apostolidis, Christos; Bruchertseifer, Frank; Abbas, Kamel; Morgenstern, Alfred

2010-02-01

184

Potential Demand for Ecotourism in the Tapajos National Forest, Para, Brazil.  

National Technical Information Service (NTIS)

Sustainable forest management is a global issue of increasing importance. As part of an effort to evaluate sustainable forest management alternatives for the Tapajos National Forest (TNF) in Para, Brazil, IBAMA (The Brazilian Institute for Environment and...

1997-01-01

185

Cold-plasma assisted hydrophobisation of cellulose fibres with styrene and para-halogenated homologues  

NASA Astrophysics Data System (ADS)

Cold-plasma-assisted treatment of additive-free hand sheet paper samples with styrene (ST), para-fluorostyrene (FST), para-fluoro-?-methylstyrene (FMST) and para-chloro-?-methylstyrene (ClMST) and para-bromostyrene (BrST) was studied and found that the grafting has occurred efficiently, as established by contact angle measurement. Thus, after solvent extraction of the modified substrates, in order to remove unbounded grafts, the contact angle value of a drop of water deposited at the surface of paper increased from 40° for unmodified substrate to 102, 99, 116, 100 and 107°, for ST-, FST- FMST-, ClMST- and BrST-treated samples, respectively, indicating that the surface has became totally hydrophobic. In fact, the polar component of the surface energy of treated samples decreased from 25 mJ/m2 to practically zero, indicating that treated surfaces were rendered totally non polar.

Gaiolas, C.; Costa, A. P.; Santos Silva, M. J.; Belgacem, M. N.

2012-07-01

186

Contribuições para o projeto da câmara infravermelha Spartan do telescópio SOAR  

NASA Astrophysics Data System (ADS)

Como parte de uma colaboração entre a Divisão de Astrofísica do INPE, IAG-USP, Instituto do Milênio MEGALIT e a Michigan State University, trabalhamos durante um ano junto ao grupo do Dr. Edwin Loh (MSU) no projeto e detalhamento de diversos subsistemas para a câmara infravermelho Spartan do telescópio SOAR. Trata-se de um imageador para as bandas J, H e K que explora todo o potencial, em termos de qualidade de imagem e campo de visada, fornecido pelo sistema de óptica adaptativa de primeira ordem do telescópio SOAR. Projetamos soluções detalhadas para os subsistemas de rodas de filtros/grismas/máscaras de Lyot; subsistema de compactação do mosaico de detectores em duas versões distintas; subsistema de alimentação de Nitrogênio líquido. Mantivemos sempre uma supervisão geral sobre todas as partes restantes e os respectivos envelopes volumétricos produzindo soluções para a integração de todos os componentes. Neste trabalho, ilustramos as principais contribuições e fornecemos um resumo do estado atual do instrumento.

Laporte, R.; Jablonski, F.; Loh, E.

2003-08-01

187

Significance of CIELAB parameters in the routine analysis of red wines Relevancia de los parámetros CIELAB en el análisis de rutina de vinos tintos  

Microsoft Academic Search

Correlations have been sought among different parameters (total polyphenols, anthocyanins and flavonoids, monomeric anthocyanins, Zn, Cu, Mn, and Fe) analyzed in two consecutive vintages of a Tempranillo wine. A comparative study of those parameters with color characteristics (both CIELAB and Glories parameters) is presented for these wines. Principal Component Analysis (PCA) has showed the existence of a close relationship between

I. Esparza; C. Santamaría; I. Calvo; J. M. Fernández

2009-01-01

188

Río Tinto Faulted Volcanosedimentary Deposits as Analog Habitats for Extant Subsurface Biospheres on Mars: A Synthesis of the MARTE Drilling Project Geobiology Results  

NASA Astrophysics Data System (ADS)

Reconstruction of the probable habitats hosting the detected microbial communities through the integration of the geobiological data obtained from the MARTE drilling campaigns, TEM sounding and field surface geological survey

Fernández-Remolar, D. C.; Prieto-Ballesteros, O.; Rodríguez, N.; Dávila, F.; Stevens, T.; Amils, R.; Gómez-Elvira, J.; Stoker, C. R.

2005-03-01

189

Mars Analog Research and Technology Experiment (MARTE): A Simulated Mars Drilling Mission to Search for Subsurface Life at the Rio Tinto, Spain  

NASA Astrophysics Data System (ADS)

MARTE is a Mars analog drilling experiment to search for subsurface life on Mars while also characterizing a sulfide-based subsurface biosphere. MARTE is among the first set of field experiments supported by the ASTEP program.

Stoker, C. R.; Lemke, L. G.; Mandell, H.; McKay, D.; George, J.; Gomez-Elvira, J.; Amils, R.; Stevens, T.; Miller, D.

2003-03-01

190

The Tinto River, an extreme acidic environment under control of iron, as an analog of the Terra Meridiani hematite site of Mars  

Microsoft Academic Search

One remarkable discovery in Mars geology is the extensive Meridiani iron formation. Although thermal oxidation mechanisms have been proposed for its origin, geomorphology and IR spectroscopy studies support an aqueous scenario as the most feasible environment to host its secondary iron-enriched mineralogy. Terrestrial hydrothermal systems or the iron-rich Precambrian oceans have been proposed as analogs to understand these interesting Martian

D. Fernandez-Remolar; J. Gomez-Elvira; F. Gomez; E. Sebastian; J. Mart??in; J. A. Manfredi; J. Torres; C. González Kesler; R. Amils

2004-01-01

191

Path Integral Monte Carlo Studies of molecular para-hydrogen clusters  

Microsoft Academic Search

Using the path integral Monte Carlo method, we have extensively studied para-hydrogen clusters, (pH_2)_N, with 6<= N <= 35 as a function of temperature. Small molecular para-hydrogen clusters are predicted to be superfluid at temperatures below about 2K. In view of recent experiments, we characterize the structual and energetic properties over the temperature range T = 1 - 10K using

Kwangsik Nho; Doerte Blume

2004-01-01

192

Thermal characterization of para- tert-butylphenol formaldehyde epoxy-acrylic resin cured with reactive diluents  

Microsoft Academic Search

The thermal decomposition of para-tert-butylphenol formaldehyde epoxy-acrylic resin as such or in the presence of reactive diluents based on glycidyl ethers of phenol and para-alkyl substituted phenols has been studied using pyrolysis in combination with gas chromatography and thermogravimetric techniques. The samples analysed in the range of temperatures between 200 and 600°C degrade statistically by a radical mechanism. The decomposition

C. N. Ca?caval; D. Ro?u; A. Stoleriu

2000-01-01

193

Observation of Ortho-Para H+3 Selection Rules in Plasma Chemistry  

NASA Astrophysics Data System (ADS)

Intensity ratios of infrared spectral lines of ortho- and para- H+3 have been measured in hydrogen plasmas using normal and para- H2. Large dependences of the intensity ratios on the parent gases have been observed, indicating the spin memory of protons even after chemical reactions. The results clearly demonstrate the existence of selection rules on nuclear spin modifications in chemical reactions theoretically anticipated by M. Quack [Mol. Phys. 34, 477 (1977)].

Uy, Dairene; Cordonnier, Michel; Oka, Takeshi

1997-05-01

194

Blurring the boundaries between professional and para-professional catalogers at California State University, Northridge  

Microsoft Academic Search

What used to be a clear-cut division between the duties of professional and para-professional catalogers has become blurred in many libraries. The authors will illustrate this point by discussing the evolution of responsibilities held by para-professional and professional catalogers over the course of a 10-year period in the Cataloging Department at California State University, Northridge (CSUN). Comparisons will be made

Jina Choi Wakimoto; Gina R Hsiung

2000-01-01

195

ParaDIS: A relational database for the consistent documentation and analysis of metamorphic mineral assemblages  

Microsoft Academic Search

A set of integrated computer programs has been developed to optimize documentation, storage, and analysis of petrological data. Primary petrographic and mineral chemistry data, as well as petrological results (such as stability diagrams) derived from these data, are documented by a relational database named ParaDIS (Paragenetic Data Inventory System).ParaDIS is implemented using INGRES™, a commercial relational database-management system running under

D. R. Schmatz; M. Engi; J. E. Lieberman

1995-01-01

196

Rhabdomyolysis and acute renal failure in a child with para-influenza type 1 infection  

Microsoft Academic Search

We present a rare case of para-influenza type 1 virus-induced rhabdomyolysis, complicated by acute renal failure (ARF). The\\u000a child underwent continuous venovenous haemofiltration and has shown full clinical and biochemical recovery. ARF due to rhabdomyolysis\\u000a in para-influenza type 1 infection in a child has, to the best of our knowledge, not been previously reported.

Renata Vrsalovic; Goran Tesovic; Branko Mise

2007-01-01

197

Synthesis and biological activity of Para-substituted 3?-phenyl docetaxel analogs  

Microsoft Academic Search

An expedient route for semisynthetic para-modified 3?-phenyl docetaxel analogs is described using the initial regioselective iodination of the oxazolidinecarboxylate 3. Palladium catalyzed coupling reactions of the iodo intermediate 4 with alkenyl and aryl boronic acids and alkynes led after alkaline hydrolysis to a series of N,O-protected para-substituted phenylisoserines 6. Coupling with 10-deacetyl-7, 10-O-diTroc-baccatin III followed by standard deprotections and acylation

Jean-Dominique Bourzat; François Lavelle; Alain Commerçon

1995-01-01

198

ParA ATPases can move and position DNA and subcellular structures.  

PubMed

Prokaryotic chromosomes and plasmids can be actively segregated by partitioning (par) loci. The common ParA-encoding par loci segregate plasmids by arranging them in regular arrays over the nucleoid by an unknown mechanism. Recent observations indicate that ParA moves plasmids and chromosomes by a pulling mechanism. Even though ParAs form filaments in vitro it is not known whether similar structures are present in vivo. ParA of P1 forms filaments in vitro at very high concentrations only and filament-like structures have not been observed in vivo. Consequently, a 'diffusion-ratchet' mechanism was suggested to explain plasmid movement by ParA of P1. We compare this mechanism with our previously proposed filament model for plasmid movement by ParA. Remarkably, ParA homologues have been discovered to arrange subcellular structures such as carboxysomes and chemotaxis sensory receptors in a regular manner very similar to those of the plasmid arrays. PMID:21963112

Szardenings, Florian; Guymer, David; Gerdes, Kenn

2011-12-01

199

Ghost loci imply Hox and ParaHox existence in the last common ancestor of animals.  

PubMed

Hox genes are renowned for patterning animal development, with widespread roles in developmental gene regulation. Despite this importance, their evolutionary origin remains obscure, due to absence of Hox genes (and their evolutionary sisters, the ParaHox genes) from basal lineages and because the phylogenies of these genes are poorly resolved. This has led to debate about whether Hox and ParaHox genes originated coincidently with the origin of animals or instead evolved after the divergence of the earliest animal lineages. Here we use genomic synteny and Monte Carlo-based simulations to resolve Hox/ParaHox origins, our approach being independent of poorly resolved homeodomain phylogenies and better able to accommodate gene loss. We show Trox-2 of placozoans occupies a ParaHox locus. In addition, a separate locus sharing synteny and hence homology with human Hox loci exists in the placozoan genome, but without a Hox-like gene in it. We call this second locus a "ghost" Hox locus, because it is homologous to the human Hox loci, but does not itself contain a Hox gene. Extending our approach to sponges, we discover distinct ghost Hox and ParaHox loci. Thus, distinct Hox and ParaHox loci were present in the last common ancestor of all living animal lineages. PMID:23022064

Mendivil Ramos, Olivia; Barker, Daniel; Ferrier, David E K

2012-10-23

200

Intensity-modulated Radiation Therapy Versus Para-aortic Field Radiotherapy to Treat Para-aortic Lymph Node Metastasis in Cervical Cancer: Prospective Study  

PubMed Central

Aim To compare dosimetry, efficacy, and toxicity of intensity-modulated radiation therapy (IMRT) with para-aortic field radiotherapy in patients with para-aortic lymph node (PALN) metastasis of cervical cancer. Methods This prospective study examined 60 patients with cervical cancer with PALN metastasis who underwent whole-pelvis radiotherapy followed by brachytherapy between November 1, 2004 and May 31, 2008. After 3 cycles of chemotherapy, patients were serially allocated into two groups and treated with IMRT or para-aortic field RT at doses of 58-68 Gy and 45-50 Gy, respectively. Treatment response was evaluated and toxicities were assessed. Patients in the IMRT group were treated with both para-aortic field RT and IMRT in order to compare the exposure dose of organs at risk. Results In the IMRT group, the mean dose delivered to the planning target volume was 67.5 Gy. At least 99% of the gross tumor volume received effective coverage and radical dose (median, 63.5 Gy; range, 54.5-66) during treatment. IMRT plans yielded better dose conformity to the target and better sparing of the spinal cord and small intestine than para-aortic field RT. The IMRT patients experienced less acute and chronic toxicities. The IMRT group also had higher 2- and 3-year survival rates than the para-aortic RT group (2-year, 58.8% vs 25.0%, P = 0.019; 3-year, 36.4% vs 15.6%, P = 0.016). However, no significant difference was found in 1-year survival (67.7% vs 51.3%, P =0.201). The median survival in the IMRT group was 25 months (range, 3 to 37 months). The actuarial overall survival, disease-free survival, and locoregional control rates at 2 years were 67%, 77%, and 88%, respectively. Conclusions IMRT provides better clinical outcomes than para-aortic field radiotherapy in patients with PALN metastasis. However, cervical local and distal recurrence remain a problem. Long-term follow-up and studies involving more patients are needed to confirm our results.

Du, Xue-lian; Sheng, Xiu-gui; Jiang, Tao; Yu, Hao; Yan, Yu-feng; Gao, Rong; Lu, Chun-hua; Li, Qing-shui

2010-01-01

201

Spontaneous Emission Between - and Para-Levels of Water-Ion H_2O^+  

NASA Astrophysics Data System (ADS)

Nuclear spin conversion interaction of water ion, H_2O^+, has been studied to derive spontaneous emission lifetime between ortho- and para-levels. H_2O^+ is a radical ion with the ^2B_1 electronic ground state. Its off-diagonal electron spin-nuclear spin interaction term, Tab(S_a? I_b + S_b? I_a), connects para and ortho levels, because ? I = I_1 - I_2 has nonvanishing matrix elements between I = 0 and 1. The mixing by this term with Tab = 72 MHz predicted by ab initio theory in the MRD-CI/Bk level, is many orders of magnitude larger than for closed shell molecules because of the large magnetic interaction due to the un-paired electron. Using the molecular constants reported by Mürtz et al. by FIR-LMR, we searched for ortho and para coupling channels below 1000 cm-1 with accidental near degeneracy between para and ortho levels. For example, hyperfine components of the 42,2(ortho) and 33,0(para) levels mix by 1.2 × 10-3 due to their near degeneracy (? E = 0.417 cm-1), and give the ortho-para spontaneous emission lifetime of about 0.63 year. The most significant low lying 10,1(para) and 11,1(ortho) levels, on the contrary, mix only by 8.7 × 10-5 because of their large separation (? E = 16.267 cm-1) and give the spontaneous emission lifetime from 10,1(para) to 00,0(ortho) of about 100 year.These results qualitatively help to understand the observed high ortho- to para- H_2O^+ ratio of 4.8 ± 0.5 toward Sgr B2 but they are too slow to compete with the conversion by collision unless the number density of the region is very low (n ˜1 cm-3) or radiative temperature is very high (T_r > 100 K). M. Staikova, B. Engels, M. Peric, and S.D. Peyerimhoff, Mol. Phys. 80, 1485 (1993) P. Mürtz, L.R. Zink, K.M. Evenson, and J.M. Brown J. Chem. Phys. 109, 9744 (1998). LP. Schilke, et al., A&A 521, L11 (2010).

Tanaka, Keiichi; Harada, Kensuke; Nanbu, Shinkoh; Oka, Takeshi

2012-06-01

202

The Formaldehyde Ortho/Para Ratio as a Probe of Dark Cloud Chemistry and Evolution  

NASA Astrophysics Data System (ADS)

We present measurements of the H2CO ortho/para ratio toward four star-forming cores, L723, L1228, L1527, and L43, and one quiescent core, L1498. Combining these data with earlier results by Minh et al., three quiescent cores are found to have ortho/para ratios near 3, the ratio of statistical weights expected for gas-phase formation processes. In contrast, ortho/para ratios are 1.5-2.1 in five star-forming cores, suggesting thermalization at a kinetic temperature of 10 K. We attribute modification of the ortho/para ratio in the latter cores to formation and/or equilibration of H2CO on grains with subsequent release back into the gas phase due to the increased energy inputs from the forming star and outflow. We see accompanying enhancements in the H2CO abundance relative to H2 to support this idea. The results suggest that the formaldehyde ortho/para ratio can differentiate between quiescent cores and those in which low-mass star formation has occurred.

Dickens, J. E.; Irvine, W. M.

1999-06-01

203

ParaPep: a web resource for experimentally validated antiparasitic peptide sequences and their structures.  

PubMed

ParaPep is a repository of antiparasitic peptides, which provides comprehensive information related to experimentally validated antiparasitic peptide sequences and their structures. The data were collected and compiled from published research papers, patents and from various databases. The current release of ParaPep holds 863 entries among which 519 are unique peptides. In addition to peptides having natural amino acids, ParaPep also consists of peptides having d-amino acids and chemically modified residues. In ParaPep, most of the peptides have been evaluated for growth inhibition of various species of Plasmodium, Leishmania and Trypanosoma. We have provided comprehensive information about these peptides that include peptide sequence, chemical modifications, stereochemistry, antiparasitic activity, origin, nature of peptide, assay types, type of parasite, mode of action and hemolytic activity. Structures of peptides consisting of natural, as well as modified amino acids have been determined using state-of-the-art software, PEPstr. To facilitate users, various user-friendly web tools, for data fetching, analysis and browsing, have been integrated. We hope that ParaPep will be advantageous in designing therapeutic peptides against parasitic diseases. Database URL: http://crdd.osdd.net/raghava/parapep/ PMID:24923818

Mehta, Divya; Anand, Priya; Kumar, Vineet; Joshi, Anshika; Mathur, Deepika; Singh, Sandeep; Tuknait, Abhishek; Chaudhary, Kumardeep; Gautam, Shailendra K; Gautam, Ankur; Varshney, Grish C; Raghava, Gajendra P S

2014-01-01

204

The formaldehyde ortho/para ratio as a probe of dark cloud chemistry and evolution  

NASA Technical Reports Server (NTRS)

We present measurements of the H2CO ortho/para ratio toward four star-forming cores, L723, L1228, L1527, and L43, and one quiescent core, L1498. Combining these data with earlier results by Minh et al., three quiescent cores are found to have ortho/para ratios near 3, the ratio of statistical weights expected for gas-phase formation processes. In contrast, ortho/para ratios are 1.5-2.1 in five star-forming cores, suggesting thermalization at a kinetic temperature of 10 K. We attribute modification of the ortho/para ratio in the latter cores to formation and/or equilibration of H2CO on grains with sub-sequent release back into the gas phase due to the increased energy inputs from the forming star and outflow. We see accompanying enhancements in the H2CO abundance relative to H, to support this idea. The results suggest that the formaldehyde ortho/para ratio can differentiate between quiescent cores and those in which low-mass star formation has occurred.

Dickens, J. E.; Irvine, W. M.

1999-01-01

205

Rotational excitation of HCN by para- and ortho-H2.  

PubMed

Rotational excitation of the hydrogen cyanide (HCN) molecule by collisions with para-H2(?j = 0,?2) and ortho-H2(?j = 1) is investigated at low temperatures using a quantum time independent approach. Both molecules are treated as rigid rotors. The scattering calculations are based on a highly correlated ab initio 4-dimensional (4D) potential energy surface recently published. Rotationally inelastic cross sections among the 13 first rotational levels of HCN were obtained using a pure quantum close coupling approach for total energies up to 1200 cm(-1). The corresponding thermal rate coefficients were computed for temperatures ranging from 5 to 100 K. The HCN rate coefficients are strongly dependent on the rotational level of the H2 molecule. In particular, the rate coefficients for collisions with para-H2(?j = 0) are significantly lower than those for collisions with ortho-H2(?j = 1) and para-H2(?j = 2). Propensity rules in favor of even ?j transitions were found for HCN in collisions with para-H2(?j = 0) whereas propensity rules in favor of odd ?j transitions were found for HCN in collisions with H2(?j ? 1). The new rate coefficients were compared with previously published HCN-para-H2(?j = 0) rate coefficients. Significant differences were found due the inclusion of the H2 rotational structure in the scattering calculations. These new rate coefficients will be crucial to improve the estimation of the HCN abundance in the interstellar medium. PMID:24929383

Vera, Mario Hernández; Kalugina, Yulia; Denis-Alpizar, Otoniel; Stoecklin, Thierry; Lique, François

2014-06-14

206

ParaDIS: A relational database for the consistent documentation and analysis of metamorphic mineral assemblages  

NASA Astrophysics Data System (ADS)

A set of integrated computer programs has been developed to optimize documentation, storage, and analysis of petrological data. Primary petrographic and mineral chemistry data, as well as petrological results (such as stability diagrams) derived from these data, are documented by a relational database named ParaDIS (Paragenetic Data Inventory System). ParaDIS is implemented using INGRES ™, a commercial relational database-management system running under UNIX on Sun computers. Two user-friendly applications, forms-based and menu-operated, allow for entry, retrieval, and various manipulations of any amount of petrological data. In the current version, ParaDIS is interfaced with external thermobarometric programs (e.g. TWEEQU, PTAX) based on consistent thermodynamic models, allowing for coherent interpretation of metamorphic assemblages. The results (e.g. P-T- or T-X-graphs) can be directed back into ParaDIS for further analysis and to document the interpretations. P-T-data derived for particular field areas also can be fed into graphics programs or Geographical Information Systems (GIS) for further manipulation, such as P-T-contouring, and display. Data architecture and storage structure of ParaDIS are presented in detail.

Schmatz, D. R.; Engi, M.; Lieberman, J. E.

1995-11-01

207

Estimation of Carbon Storage in Para Rubber Plantation in Eastern Thailand  

NASA Astrophysics Data System (ADS)

This study aims to estimate the carbon stock and sequestration in Para rubber plantation of East Thailand using the THAICHOTE (Thailand Earth Observation System data). For that purpose we identify the area of every stage class Para rubber plantation by the analysis of different image objects (i.e., rule base and multiple regression classifications) and we map the carbon stock and sequestration of each Para rubber class using biomass allometric regressions and carbon content equations. THAICHOTE data include Multispectral image (4 bands at 15x15 m spatial resolution), Panchromatic image (2x2 m spatial resolution) and Stereo image, data acquisition from December 2011-April 2012. The preliminary investigated area is located in Wangchun, (Eastern, Thailand) and covers about 20 Km2. Calibrating the class stage, by image analysis that integrated edge-based segmentation, reflectance, remote sensing indices, texture analysis and canopy height model (CHM), we found that best classification was obtained by multiple regression (accuracy of 80%) compared to rule base logical operation (accuracy 70%) suggesting that manual 3D stereo measurements or Light Detection And Ranging (LiDAR) both are able to construct the CHM. The results of this study indicate that for a total Para rubber biomass of 14,651 tons, the amount of stored carbon is of 7,326 tons. Mature stage of Para rubber plantations exhibits the highest capacity of sequestering with a global flux of 0.21 tons C/ Km2/year.

Charoenjit, K.; Zuddas, P.; Allemand, P.

2012-12-01

208

ParaPep: a web resource for experimentally validated antiparasitic peptide sequences and their structures  

PubMed Central

ParaPep is a repository of antiparasitic peptides, which provides comprehensive information related to experimentally validated antiparasitic peptide sequences and their structures. The data were collected and compiled from published research papers, patents and from various databases. The current release of ParaPep holds 863 entries among which 519 are unique peptides. In addition to peptides having natural amino acids, ParaPep also consists of peptides having d-amino acids and chemically modified residues. In ParaPep, most of the peptides have been evaluated for growth inhibition of various species of Plasmodium, Leishmania and Trypanosoma. We have provided comprehensive information about these peptides that include peptide sequence, chemical modifications, stereochemistry, antiparasitic activity, origin, nature of peptide, assay types, type of parasite, mode of action and hemolytic activity. Structures of peptides consisting of natural, as well as modified amino acids have been determined using state-of-the-art software, PEPstr. To facilitate users, various user-friendly web tools, for data fetching, analysis and browsing, have been integrated. We hope that ParaPep will be advantageous in designing therapeutic peptides against parasitic diseases. Database URL: http://crdd.osdd.net/raghava/parapep/

Mehta, Divya; Anand, Priya; Kumar, Vineet; Joshi, Anshika; Mathur, Deepika; Singh, Sandeep; Tuknait, Abhishek; Chaudhary, Kumardeep; Gautam, Shailendra K.; Gautam, Ankur; Varshney, Grish C.; Raghava, Gajendra P.S.

2014-01-01

209

A Review of the Theories Developed to Describe the Process of College Persistence and Attainment  

Microsoft Academic Search

\\u000a A review of the peer-reviewed papers in the top higher education journals in the last 20 years suggests that the field is\\u000a relying heavily on Tinto’s (1993, Leaving college: Rethinking the causes and cures of student attrition. Chicago: University\\u000a of Chicago Press) theory of student departure. The fact that there is limited empirical support for Tinto’s theory (Braxton,\\u000a Sullivan, &

Tatiana Melguizo

210

Identification and Characterization of Catabolic para-Nitrophenol 4Monooxygenase and para-Benzoquinone Reductase from Pseudomonas sp. Strain WBC3  

Microsoft Academic Search

Pseudomonas sp. strain WBC-3 utilizes para-nitrophenol (PNP) as a sole source of carbon, nitrogen, and energy. In order to identify the genes involved in this utilization, we cloned and sequenced a 12.7-kb fragment containing a conserved region of NAD(P)H:quinone oxidoreductase genes. Of the products of the 13 open reading frames deduced from this fragment, PnpA shares 24% identity to the

Jun-Jie Zhang; Hong Liu; Yi Xiao; Xian-En Zhang; Ning-Yi Zhou

2009-01-01

211

MODELO MATEMÁTICO PARA ESTIMAR EL ESPACIAMIENTO ENTRE DRENES SUBTERRÁNEOS EN RÉGIMEN TRANSITORIO Mathematical Model for Estimating Spacing Between Subterranean Drains in Transitory Regime  

Microsoft Academic Search

Para el diseño de sistemas de drenaje subterráneo existen diferentes modelos, tanto para régimen permanente, como transitorio; sin embargo, la mayoría de ellos no se han obtenido para condiciones de suelo y clima semiáridas. Por lo tanto, este trabajo tuvo como objetivo desarrollar una ecuación empírica para régimen transitorio que permitiera determinar el espaciamiento entre drenes paralelos, considerando los intervalos

Pablo Miguel Coras-Merino

2006-01-01

212

Ortho-para-H2 conversion by hydrogen exchange: Comparison of theory and experiment  

NASA Astrophysics Data System (ADS)

We report fully-quantum time-independent calculations of cross sections and rate coefficients for the collisional (de)excitation of H2 by H. Our calculations are based on the H3 global potential energy surface of Mielke et al. [J. Chem. Phys. 116, 4142 (2002)]. The reactive hydrogen exchange channels are taken into account. We show that the ortho-para and para-ortho conversion of H2 are significant processes at temperatures above ~300 K and for the last process we provide the first comparison with available experimental rate coefficients between 300 and 444 K. The good agreement between theory and experiment is a new illustration of our detailed understanding of the simplest chemical reaction. The importance of the ortho-para-H2 conversion by hydrogen exchange in astrophysics is discussed.

Lique, François; Honvault, Pascal; Faure, Alexandre

2012-10-01

213

Irritant contact dermatitis from a black henna tattoo without sensitization to para-phenylendiamine.  

PubMed

Allergic contact dermatitis from nonpermanent black henna tattoos has been frequently reported, particularly in children. Contamination or adulteration of the dyes with para-phenylendiamine has been identified as major cause of active sensitization and elicitation of severe allergic contact dermatitis. Sequelae include permanent sensitization, hyper- or hypopigmentation, scarring, keloids, and hypertrichosis. We report a rare case of irritant dermatitis to an unknown ingredient in a black henna tattoo with consecutive hypopigmentation. Sensitization to para-phenylendiamine and other para-compounds was excluded by patch test evaluation. This is relevant for future exposure to consumer products such as hair dyes or in occupational settings. Generally, black henna tattoos, particularly if done with dyes of unknown composition, should be strongly discouraged. PMID:23690526

Kind, Fabiola; Hofmeier, Kathrin Scherer; Bircher, Andreas J

2013-06-01

214

Terahertz absorption spectrum of para and ortho water vapors at different humidities at room temperature  

NASA Astrophysics Data System (ADS)

Terahertz time-domain spectroscopy has been used to measure the absorption of water vapor in 0.2-2.4 THz range from low to high humidity at room temperature. The observed absorption lines are due to the water molecular rotations in the ground vibrational state. We find that the absorption strength of para transitions increases as humidity increases, while the absorption strength of ortho transitions increases and then decreases in intensity with increasing humidity. We explain this difference based on the nuclear spin statistics based ratio of ortho to para water monomer populations at room temperature. The preferential adsorption on the solid surfaces of para water leads to an ortho dominated vapor cloud whose monomer rotational absorption intensity decreases due to the effects of dimerization, molecular collisions, clustering, and interactions with liquid droplets at high concentrations.

Xin, X.; Altan, H.; Saint, A.; Matten, D.; Alfano, R. R.

2006-11-01

215

Superfluid Effects in PARA-H_2 Clusters Probed by CO_2 Rotation-Vibration Transitions  

NASA Astrophysics Data System (ADS)

The prospect of directly observing superfluidity in para-H_2 is a tantalizing but elusive goal. Like ^4He, para-H_2 is a light zero-spin boson. However, H_2-H_2 intermolecular interactions, though weak, are stronger than He-He interactions, and hydrogen is a solid below about 14 K. This makes detection of superfluidity in bulk hydrogen problematical, to say the least. But there are still possibilities for para-H_2 in the form of clusters or in nano-confined environments, and superfluid transition temperatures as high as ˜6 K have been predicted. Spectroscopic observations of (para-H_2)_N-CO_2 clusters were at first very difficult to interpret for N > 5. However, with the help of path integral Monte Carlo simulations and an accurate new H_2-CO_2 intermolecular potential surface which explicitly incorporates dependence on the CO_2 ?b{3} asymmetric stretch, it is now possible to achieve a remarkably consistent picture of (para-H_2)_N-CO_2 clusters in the size range N = 1 ˜ 20. By combining the experimental spectroscopic measurements and theoretical simulations, we determine the size evolution of the superfluid response of the CO_2-doped para-H_2 clusters, which peaks for the "magic" number N = 12. V. L. Ginzburg and A. A. Sobyanin, JETP Lett. 15, 343 (1972). A. R. W. McKellar, Paper WH04, 63rd OSU International Symposium on Molecular Spectroscopy, June 16-20, 2008. H. Li, P.-N. Roy, and R. J. Le Roy, J. Chem. Phys., submitted.

Li, Hui; Le Roy, Robert J.; Roy, Pierre-Nicholas; McKellar, A. R. W.

2010-06-01

216

Um supressor de fundo térmico para a câmara infravermelha CamIV  

NASA Astrophysics Data System (ADS)

O ângulo sólido subtendido pelos pixels na câmara infravermelha do NexGal (CamIV) que operamos no OPD/LNA contém contribuições provenientes do sistema de coleta de fluxo propriamente dito - sendo esta a parte que interessa para as medidas astronômicas - e contribuições da obstrução central, sistema de suporte do espelho secundário e região exterior à pupila de entrada do telescópio. Estas últimas contribuições são devi-das à emissão de corpo negro à temperatura ambiente e aumentam exponencialmente para comprimentos de onda maiores que 2 micra (banda K, no infravermelho próximo). Embora a resultante pode ser quantificada e subtraída dos sinais relevantes, sua variância se adiciona à variância do sinal, e pode ser facilmente a contribuição domi-nante para a incerteza final das medidas, tornando ineficiente o processo de extração de informação e degradando a sensibilidade da câmara. A maneira clássica de resolver esse problema em sistemas ópticos que operam no infravermelho, onde os efeitos da emissão térmica do ambiente são importantes, é restringir o ângulo sólido subtendido pelos pixels individuais exclusivamente aos raios provenientes do sistema óptico. Para tanto, projeta-se uma imagem real, bastante reduzida, da pupila de entrada do sistema óptico num anteparo que transmita para o sistema de imageamento só o que interessa, bloqueando as contribuições das bordas externas à pupila de entrada, obstrução central do telescópio e sistema de suporte. Como a projeção é realizada em ambiente criogênico, a contribuição térmica espúria é efetivamente eliminada. Nós optamos por um sistema do tipo Offner para implementar na prática esta função. Trata-se de um sistema baseado em espelhos esféricos, bastante compacto e ajustado por construção. A opção por espelhos do mesmo material que o sistema de suporte (Alumínio) minimiza a dilatação diferencial, crítica nesse tipo de aplicação. Apresentamos as soluções detalhadas do projeto óptico-mecânico, bem como uma análise de flexões e desempenho em termos de qualidade de imagem.

Jablonski, F.; Laporte, R.

2003-08-01

217

Large scale visualization on the Cray XT3 using ParaView.  

SciTech Connect

Post-processing and visualization are key components to understanding any simulation. Porting ParaView, a scalable visualization tool, to the Cray XT3 allows our analysts to leverage the same supercomputer they use for simulation to perform post-processing. Visualization tools traditionally rely on a variety of rendering, scripting, and networking resources; the challenge of running ParaView on the Lightweight Kernel is to provide and use the visualization and post-processing features in the absence of many OS resources. We have successfully accomplished this at Sandia National Laboratories and the Pittsburgh Supercomputing Center.

Rogers, David; Geveci, Berk (Kitware, Inc.); Eschenbert, Kent (Pittsburgh Supercomputing Center); Neundorf, Alexander (Technical University of Kaiserslautern); Marion, Patrick (Kitware, Inc.); Moreland, Kenneth D.; Greenfield, John

2008-05-01

218

Development of polymorphic microsatellite markers for the livebearing fish Poecilia parae.  

PubMed

We developed 16 novel polymorphic tetranucleotide microsatellite markers for Poecilia parae, a livebearing fish used in evolutionary studies because of its Y-linked colour and size polymorphism. A set of 199 clones was sequenced out of an enriched genomic library, and we achieved an enrichment efficiency of nearly 80%. Primers were designed for 16 pure repeats, and 59 P. parae were screened for polymorphism. Cross-amplification was tested on Poecilia picta and Poecilia reticulata, the guppy. The new microsatellite markers showed an exceptionally high allelic diversity and low stutter formation, proving their suitability for a broad range of applications in these species. PMID:21585912

Nater, Alexander; Krützen, Michael; Lindholm, Anna K

2008-07-01

219

Quantum rotation of ortho and para-water encapsulated in a fullerene cage  

PubMed Central

Inelastic neutron scattering, far-infrared spectroscopy, and cryogenic nuclear magnetic resonance are used to investigate the quantized rotation and ortho–para conversion of single water molecules trapped inside closed fullerene cages. The existence of metastable ortho-water molecules is demonstrated, and the interconversion of ortho-and para-water spin isomers is tracked in real time. Our investigation reveals that the ground state of encapsulated ortho water has a lifted degeneracy, associated with symmetry-breaking of the water environment.

Beduz, Carlo; Carravetta, Marina; Chen, Judy Y.-C.; Concistre, Maria; Denning, Mark; Frunzi, Michael; Horsewill, Anthony J.; Johannessen, Ole G.; Lawler, Ronald; Lei, Xuegong; Levitt, Malcolm H.; Li, Yongjun; Mamone, Salvatore; Murata, Yasujiro; Nagel, Urmas; Nishida, Tomoko; Ollivier, Jacques; Rols, Stephane; Room, Toomas; Sarkar, Riddhiman; Turro, Nicholas J.; Yang, Yifeng

2012-01-01

220

An excellent Pd-based nanocomposite catalyst for the selective hydrogenation of para-chloronitrobenzene  

Microsoft Academic Search

A partially reduced Pd\\/?-Fe2O3 nanocomposite catalyst (Pd\\/?-Fe2O3-PR) was prepared using PdO and ferric hydroxide colloidal particles as starting materials. This catalyst exhibited excellent catalytic properties for the selective hydrogenation of para-chloronitrobenzene (p-CNB) to para-chloroaniline (p-CAN). The selectivity to p-CAN reached 99.2% at complete conversion of the substrate and intermediates, and the hydrodechlorination of p-CAN was fully suppressed over Pd\\/?-Fe2O3-PR. The

Hongquan Liu; Minghui Liang; Chao Xiao; Ning Zheng; Xuhui Feng; Yan Liu; Jinglin Xie; Yuan Wang

2009-01-01

221

In search of higher persistence rates in distance education online programs  

Microsoft Academic Search

Tinto's [Rev. Educ. Res. 45 (1975) 89; Tinto, V. (1987). Leaving college. Chicago: The University of Chicago Press; Tinto, V. (1993). Leaving college: rethinking the causes and cures of student attrition. Chicago: The University of Chicago Press] student integration model and Bean and Metzner's [Rev. Educ. Res. 55 (1985) 485] student attrition model have been influential in explaining persistence and

Alfred P. Rovai

2003-01-01

222

Performance characteristics of magnesium/para-nitrophenol cells in 2:1 magnesium electrolytes  

SciTech Connect

1 V/1 Ah magnesium/para-nitrophenol (PNP) reserve cells were fabricated and their performance was evaluated in different electrolytes [2M aqueous solutions of Mg(C1O[sub 4])[sub 2], MgCl[sub 2], and MgBr[sub 2

Kumar, G.; Sivashanugam, A.; Sridharan, R. (Central Electrochemical Research Inst., Karaikudi (India))

1993-11-01

223

EMPLEO DE FRACCIONES CELULARES DE LA LEVADURA Saccharomyces cerevisiae COMO ADITIVO ALIMENTARIO PARA Artemia franciscana  

Microsoft Academic Search

RESUMEN En el presente estudio se evalúa la levadura Saccharomyces cerevisiae de forma desintegrada (LD) y tres fracciones celulares obtenidas de ella: complejo pared-membrana (FP), núcleo-proteínas (FN) y citoplasma (FC) como aditivo alimentario utilizando al crustáceo Artemia franciscana como modelo de experimentación. Se realizaron dos bioensayos para determinar el efecto que ejercían dichos aditivos en el crecimiento, biomasa seca, supervivencia

Yamilé Comabella; Tsai García-Galano; Olimpia Carrillo; Yadir Mauri

224

Cuadro de mando y sistemas de información: herramientas estratégicas para la gestión medioambiental corporativa  

Microsoft Academic Search

En la actualidad protección del ambiente es un nuevo e importante objetivo estratégico de las empresas cubanas y del mundo. La información medioambiental se vuelve cada vez más relevante para las decisiones económicas, por lo que es necesario manejarla de manera oportuna. Muchas entidades presentan Sistemas de Gestión Medioambientales según NC ISO 14000 que se quedan en fases meramente declarativas

Frank Medel; Lourdes García; Liesby Gómez; Rebeca Pentón

2011-01-01

225

A Compendium of Provisions for a Model Ordinance for the Regulation of Public Para-Transit.  

National Technical Information Service (NTIS)

This report comprises a complete set of provisions for the regulation of various types of public para-transit transportation. Its preparation consisted for five stages: Collection and analysis of the statutes of every state, the ordinances of some 600 mun...

R. E. Samuels

1976-01-01

226

LIBROS DE MÚSICA PARA EL NUEVO MUNDO EN EL SIGLO XVI  

Microsoft Academic Search

En el Archivo General de Indias de Sevilla se conserva el expediente de un pleito que enfrentó a Alonso Pérez, copista y clérigo de Medina del Campo, y a Francisco Fernández de Córdoba, conocido impresor de Valladolid, en activo entre 1541 y 1570. Cada uno de los litigantes pretendía los derechos de publicación de los cantorales para las Indias, en

Emilio Ros-Fábregas

2001-01-01

227

Computer-controlled radiation therapy machine for pelvic and para-aortic nodal areas  

Microsoft Academic Search

A computer-controlled radiation therapy technique has been developed to treat cancer of the uterine cervix that has extended to the pelvic and para-aortic lymph nodes. During five longitudinal scans with a 4 cm wide 8 MV X ray beam, conformation of the high dose region to the target volume was achieved primarily by varying the other field dimensions. Treatment planning

Lee M. Chin; Peter K. Kijewski; Göran K. Svensson; John T. Chaffey; Martin B. Levene; B. E. Bjaerngard

1981-01-01

228

Factor Structure of the Escala de Autoeficacia para la Depresión en Adolescentes (EADA)  

Microsoft Academic Search

The current concept and measures of self-efficacy for depression in adolescents do not consider developmental and cultural aspects essential to understand and assess this construct in Latino youth. We examined the factor structure of the Escala de Autoeficacia para la Depresión en Adolescentes (EADA), a Spanish instrument designed to assess this construct as experienced by this population. Participants were 116

Mirella Díaz-Santos; Eduardo Cumba-Avilés; Guillermo Bernal; Carmen Rivera-Medina

2011-01-01

229

Hacia un framework Orientado a Objetos para Bills of Materials Complejos  

Microsoft Academic Search

Las empresas de producción industrial se enfrentan por un lado, a los cambios constantes de las condiciones del mercado, como po r ejemplo, los patrones de demanda, ciclo de vida de los productos mucho más cortos, etc. Por otro, a un mercado global, que requiere que la cadena de suministros, alcance muy altos niveles de eficiencia. Para mantener la competitividad

Marcela Vegetti; Gabriela Henning; Horacio Leone

230

Un Juego de Gravedad con Reconocimiento de Voz para Niños con Problemas de Lenguaje  

Microsoft Academic Search

En este trabajo presentamos un juego electrónico (Gravedad) con reconocimiento de voz para estimular a niños en edad escolar con problemas del lenguaje dislalia. Se presenta las características y elementos del juego electrónico, así como su integración con el sistema de reconocimiento de voz y los resultados de unas pruebas de usabilidad. El juego de Gravedad se desarrolló utilizando el

Carlos Miranda-Palm; Reyna Camal-U; José Cen-Magaña; Cinhtia Gonzalez-Segura; Sergio Gonzalez-Segura; Michel García; Lizzie Narvaez-Díaz

231

Estados Unidos y cuatro países de América Latina se unen para combatir el cáncer  

Cancer.gov

El Instituto Nacional del Cáncer (NCI) de Estados Unidos formalizó esta semana alianzas bilaterales con los gobiernos de Argentina, Brasil, México y Uruguay, para acelerar el avance contra el cáncer en la población hispana de Estados Unidos y de América Latina y mejorar la investigación del cáncer.

232

Aprovechamiento de los mercados financieros internacionales para gestionar el riesgo de amenazas naturales en América Latina  

Microsoft Academic Search

El presente informe técnico analiza la potencial aplicación práctica de los instrumentos financieros diseñados para el financiamiento y la transferencia del riesgo de las amenazas naturales en América Latina. En primer lugar, se presenta, en términos generales, el papel del financiamiento y de la transferencia de los riesgos en la gestión del riesgo de desastres. Luego se analiza las fuentes

Ivar Pettersen; John Magne Skjelvik; Nils Atle Krokeide

2006-01-01

233

Caracterización del mercado de energía elétrica para usuarios no regulados en Colombia  

Microsoft Academic Search

En este artículo se presenta un análisis sobre las características del mercado de energía para usuarios no regulados en Colombia, el cual puede ser considerado como un sub-mercado dentro del mercado global de energía eléctrica en Colombia. En este análisis se incluye un indicador de concentración de mercado (Herfindahl-Hirschman), así como los porcentajes de participación en cubrimiento de demanda y

Ana Cecilia Escudero; Sergio Botero Botero

2006-01-01

234

Sindicalismo docente, gobiernos y reformas educativas en América Latina y el Caribe: Condiciones para el diálogo  

Microsoft Academic Search

Este documento fue comisionado por la Red de Educación del Diálogo Regional de Política para la 9a Reunión Hemisférica celebrada entre los días 8 y 10 de noviembre de 2006. El trabajo está dividido en cuatro partes: se presenta una breve y esquemática caracterización del contexto y de las reformas educativas; se desarrolla un panorama general de las características de

Mariano Palamidessi; Martín Legarralde

2006-01-01

235

GOBIERNO ELECTRÓNICO: FASES, DIMENSIONES Y ALGUNAS CONSIDERACIONES A TENER EN CUENTA PARA SU IMPLEMENTACIÓN  

Microsoft Academic Search

El uso de las TIC cambia radicalmente la forma en que los gobiernos administran y ejecutan sus procesos internos, y abre la posibilidad de mejorar e incrementar los canales de comunicación con los ciudadanos. Así, el gobierno electrónico se observa como un medio para que los gobiernos modernicen sus procesos, mejoren sus interacciones con los ciudadanos y disminuyan la fractura

Roberto de Armas Urquiza; Alejandro de Armas Suárez

2011-01-01

236

EL TLC CA-EE.UU.: ¿Una Oportunidad de Crecimiento para los Paises Centroamericanos¿  

Microsoft Academic Search

Esta presentación fue comisionado por la Red de Integración y Comercio del Diálogo Regional de Política para la V Reunión Hemisférica celebrada los días 14 y 15 de agosto de 2003. Antecedentes Motivos y Razones de la Negociación Objetivos Generales de la Negociación Características y Estructura de la Negociación Contenido del TLC Agenda Integral de Cooperación Avances de la negociación

Gabriela Llobet

2003-01-01

237

Carencia de hierro en la infancia: Causas y consecuencias para el desarrollo infantil  

Microsoft Academic Search

ResumenSe comentan brevemente las causas principales de la carencia de hierro (CH), seguido de un examen de los estudios sobre la CH y el desarrollo y comportamiento cognitivos y motores del niño para probar un vínculo causal, clasificando dichos estudios por su diseño. La anemia por carencia de hierro (ACH) se asocia a numerosos inconvenientes psicosociales y económicos que pueden

Sally Grantham-McGregor; Helen Baker-Henningham

2010-01-01

238

La actuación pública para el fomento de nuevas empresas Hacia un enfoque de política económica  

Microsoft Academic Search

A lo largo de este trabajo abordaremos la tarea de analizar el perfil de las distintas actuaciones y la potencial existencia de una política econó- mica específica de creación de empresas, tras lo que trataremos de esta- blecer, en su caso, una posible estructura de la misma. Para alcanzar sen- dos propósitos intentaremos: revisar las líneas generales de los diferentes

José Antonio; Belso Martínez

239

30 anos de investigação sobre externalidades do IDE para as empresas nacionais: que conclusões?  

Microsoft Academic Search

Resumo: Durante as últimas três décadas, surgiu uma vasta literatura sobre a existência potencial de externalidades do IDE para as empresas domésticas traduzidas em ganhos de produtividade. Esta ocorrência relaciona-se com o facto de as empresas multinacionais possuírem activos intangíveis que podem ser transmitidos às empresas domésticas. A análise empírica não dá, contudo, indicações claras sobre o fenómeno. Neste artigo,

Nuno Crespo; Maria Paula Fontoura

2007-01-01

240

Sugestões para o uso do mini-exame do estado mental no Brasil  

Microsoft Academic Search

RESUMO - Modificações no mini-exame do estado mental (MEM) foram sugeridas anteriormente em nosso meio. Neste artigo relatamos sugestões para aplicação uniforme deste instrumento. Método: Avaliamos 433 indivíduos saudáveis sem queixas de memória através do MEM tendo seu desempenho sido avaliado quanto às variáveis demográficas. As modificações propostas foram detalhadamente descritas. Resultados: A escolaridade foi o principal fator que influenciou

Sonia M. D. Brucki; Ricardo Nitrini; Paulo Caramelli; Paulo H. F. Bertolucci; Ivan H. Okamoto

2003-01-01

241

SISTEMA REMOTO DE ADQUISICIÓN PARA EL CONTROL DEL RUIDO AMBIENTAL CON FPGA Y FPAA  

Microsoft Academic Search

RESUMEN Este artículo propone el diseño de un sistema de adquisición de datos con componentes digitales y analógicos microelectrónicos reconfigurables, como son el FPGA (Field Programmable Gate Array) y el FPAA (Field Programmable Analog Array), para monitorear y analizar la contaminación por ruido ambiental. Este prototipo obtiene los datos del ruido de una zona vial (zona centro de una ciudad)

A. Castillo Atoche; J. Vázquez Castillo; V. Sanchez Huerta; P. Del Río Dawn

242

Nivelación interterritorial e ineficiencia de las decisiones presupuestarias: reflexiones para el caso español  

Microsoft Academic Search

En este trabajo se estudian los efectos negativos de los esquemas de nivelación horizontal sobre la eficiencia en las elecciones fiscales de los gobiernos regionales. Partiendo de unos resultados teóricos básicos, se examinan los aspectos dinámicos del problema, se ofrece alguna evidencia empírica para el caso español y se presenta una solución que combina los criterios de eficiencia y equidad.

Santiago Lago Peñas

2002-01-01

243

LA ENERGÍA EN LA FORMACIÓN DE LOS SUELOS: ASPECTOS TEÓRICOS Y METODOLÓGICOS PARA SU EVALUACIÓN  

Microsoft Academic Search

RESUMEN El suelo es un sistema abierto que tiende hacia un equilibrio dinámico acumulando y reciclando materia y energía a través del tiempo. Mediante un balance energético es posible evaluar la energía acumulada o la que circula a través de su masa. Esta miscelánea tiene por objetivo presentar aspectos teóricos y metodológicos para cuantificar la energía dinamizada durante la formación

AMÉRICO DEGIOANNI; ESTELA BRICCHI; EUGENIO HAMPP

2008-01-01

244

Fondo de Compensación Regional: Igualdad de oportunidades para la periferia colombiana  

Microsoft Academic Search

En el presente documento se propone la creación de un Fondo de Compensación Regional (FCR) para impulsar el desarrollo de la periferia de Colombia, la cual concentra más del 44% de la población total y el 60% de los habitantes con Necesidades Básicas Insatisfechas (NBI). Es importante resaltar que el principio que debe orientar la política del FCR es el

Luis Armando Galvis Aponte; Adolfo meisel R

2010-01-01

245

Programa em Educação a Distância para a Melhoria das Condições de Aprendizagem da Matemática  

Microsoft Academic Search

Resumo - A fim de fundamentar uma ação pedagógica diferenciada, frente ao elevado número de reprovações e desistências que ocorrem em disciplinas iniciais de Matemática na Universidade de Caxias do Sul, apresentamos um programa através do qual investigamos as reais possibilidades de constituir nova opção para alunos reprovados em Cálculo Diferencial e Integral I. Num ambiente virtual de aprendizagem os

Isolda G. De Lima; Laurete Z. Sauer

246

Convection in the Outer Planet Atmospheres Including ortho-para Hydrogen Conversion  

Microsoft Academic Search

Convective adjustment and diffusive schemes based on terrestrial methods are extended to outer planet applications in order to develop an algorithm that can be used in dynamical modeling of outer planetary flows. Over the temperature range between 50 K and 250 K the delayed conversion of ortho- hydrogen to para-hydrogen can have large effects on stratification. One-dimensional modeling of atmospheric

Michael D. Smith; Peter J. Gierasch

1995-01-01

247

Para-Professionals in Further Education: Changing Roles in Vocational Delivery  

ERIC Educational Resources Information Center

Roles and structures within further education colleges seem to be in constant change and development; roles are becoming blurred, and lecturers are taking on more management tasks. Alongside this has been the development of para-professional roles, using non-lecturers to undertake teaching tasks. This can allow for the greater involvement of…

Scott, Gill

2005-01-01

248

ESTUDIO MESOMECÁNICO DE LA FRACTURA DEL HORMIGÓN PARA DIFERENTES VELOCIDADES DE CARGA  

Microsoft Academic Search

Resumen. En este artículo se analiza el comportamiento del hormigón a un nivel mesomecánico de observación bajo cargas de tracción uniaxial dependientes del tiempo. Como punto de partida se ha empleado un modelo mesoestructural en 2D para materiales heterogéneos basado en elementos junta de espesor nulo, desarrollado dentro del grupo de investigación de la ETSECCPB-UPC. En este modelo, la estructura

Ricardo Lorefice; Guillermo Etse; Carlos M. López; Ignacio Carol

249

Desafíos en la gestión de tecnologías de información y comunicación para Colombia: caso de internet  

Microsoft Academic Search

Resumen Actualmente Colombia alcanza el 5,4% en el nivel de penetración de internet, mientras que en economías desarrolladas se observan niveles superiores al 40%. Con el objetivo de establecer los retos que el país debe superar para reducir la amplia brecha que estas cifras evidencian, se revisó el fenómeno de internet en diferentes ámbitos, identificándose nueve factores clave que influyen

Juan Camilo Uribe Véleza; Claudia Nelcy Jiménez Hernándezb; María Elena García Vergarac

2011-01-01

250

Indicadores de gestión urbana. Los observatorios urbano-territoriales para el desarrollo sostenible. Manizales, Colombia  

Microsoft Academic Search

Los Observatorios para el Desarrollo Sostenible del Municipio de Manizales en Colombia, hacen parte del Sistema de Monitoreo diseñado por el Municipio como apoyo a la gestión urbana local. A partir de los resultados de indicadores económicos, sociales y ambientales, los ciudadanos podrán evaluar de forma permanente el desempeño de programas y proyectos del Plan de Desarrollo Municipal y participar

Luz Stella Velásquez

2001-01-01

251

UPLC-ESI-MS/MS analysis of Sudan dyes and Para Red in food.  

PubMed

An analytical method for the simultaneous determination of Sudan dyes (Sudan Red G, Sudan I, Sudan II, Sudan III, Sudan Red 7B and Sudan IV) and Para Red in food by ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-ESI-MS/MS) was developed. Samples were extracted with acetonitrile, and water added into the extract. The supernatant was analysed by UPLC-MS/MS after refrigeration and centrifugation. The sample was separated on an Acquity BEH C(18) column, and detected by MS/MS with the multiple reaction monitoring mode. Matrix calibration was used for quantitative testing of the method. The linear matrix calibrations of Sudan dyes and Para Red were 2-50 and 10-250 ng g(-1), respectively, and the regression coefficients were >0.9945. The recoveries were 83.4-112.3% with good coefficients of variation of 2.0-10.8%. The limits of detection were between 0.3 and 1.4 ng g(-1) for the six Sudan dyes, and between 3.7 and 6.0 ng g(-1) for Para Red. The limits of quantification were between 0.9 and 4.8 ng g(-1) for the six Sudan dyes, and between 12.2 and 19.8 ng g(-1) for Para Red. PMID:20582780

Li, C; Wu, Y L; Shen, J Z

2010-09-01

252

Salud Para Su Corazón: A Community-Based Latino Cardiovascular Disease Prevention and Outreach Model  

Microsoft Academic Search

Cardiovascular disease (CVD) is the leading cause of death for Latinos living in the United States. This population is generally unaware of important lifestyle or behavioral changes that can prevent CVD. The National Heart, Lung, and Blood Institute (NHLBI) designed and implemented Salud para su Corazón (Health for Your Heart), a culturally appropriate, community-based, theory-driven intervention model. NHLBI's goals were:

Rina Alcalay; Matilde Alvarado; Hector Balcazar; Eileen Newman; Elmer Huerta

1999-01-01

253

SISTEMA PARA GESTIONAR LA ACTIVIDAD CIENTÍFICA DEL DEPARTAMENTO DE INFORMÁTICA DE LA UNIVERSIDAD DE GUANTÁNAMO  

Microsoft Academic Search

El sistema para gestionar la actividad científica del Departamento de Informática de la Universidad de Guantánamo surge debido a la necesidad de gestionar de manera más rápida, segura y eficaz los procesos que se desarrollan actualmente en dicho centro. Fue desarrollado utilizando los lenguajes PHP del lado del servidor con CodeIgniter como framework y JavaScript del lado del cliente. Se

Denis Boizan Romero

2012-01-01

254

Montagem e Resultados Preliminares de Aparato Experimental para Estudo Térmico de Materiais Ablativos  

Microsoft Academic Search

O estudo do fenômeno físico de ablação, que ocorre em determinados materiais usados em sistemas de proteção térmica de satélites, bem como a caracterização das propriedades térmicas dos mesmos são considerados de grande importância, por representar um ponto estratégico para a tecnologia espacial. No Brasil, os estudos de materiais ablativos têm sido realizados dentro da perspectiva do Programa Nacional de

Gabriel Antônio de Souza Júnior; Lucas Mello de Campos Arruda; Walber Ferreira Braga; Márcia Barbosa; Henriques Mantelli

255

Bacterial Inoculum Density and Probability of para-Nitrophenol Biodegradability Test Response  

Microsoft Academic Search

This study has been carried out to establish a model linking probability of positive response in para-nitrophenol biodegradability test to controlled variables of the test (suspended solids, SS; total bacteria, AODC; cultivable bacteria, CFU; specific biodegraders, MPN). Series of dilution of 11 raw inocula (6 activated sludges, 5 river waters) were tested. They reveal very dispersed values of biomass measured

G. Thouand; P. Friant; F. Bois; A. Cartier; A. Maul; J. C. Block

1995-01-01

256

Lenguajes de libre distribución para la gestión de redes basada en políticas  

Microsoft Academic Search

La gestión basada en políticas es uno de los últimos desarrollos en el área de gestión de redes y sistemas distribuidos. Este artículo presenta una propuesta del uso de lenguajes de libre distribución para la definición, edición y almacenamiento de políticas aplicables a la gestión de redes. 1 Introducción Las redes del mundo de las telecomunicaciones de hoy en día

Angélica Reyes; Antoni Barba; Ingeniería Telemática

257

Moléculas que marcam o tempo: implicações para os fenótipos circadianos Timekeeping molecules: implications for circadian phenotypes  

Microsoft Academic Search

Resumo Objetivo: Revisar resumidamente a literatura dos últimos 36 anos de pesquisa em cronobiologia molecular a fim de informar aos profissionais de saúde os avanços obtidos nesta área e os potenciais para aplicação na clínica médica. Método: Buscas na literatura foram realizadas utilizando as bases de dados PubMed e Scopus usando como palavras-chave \\

Danyella Silva Pereira; Sergio Tufik; Mario Pedrazzoli

258

Gestión de recursos de un navegador Web para prevenir ataques contra la privacidad en Tor  

Microsoft Academic Search

Resumen—En este trabajo presentamos una propuesta para el despliegue de políticas de autorización contextuales sobre navegadores Web. El objetivo de nuestra propuesta es la automatización del proceso de control de recursos de un navegador Web cuando el contexto de navegación varía. Cuando esto sucede, los requisitos de seguridad del navegador cambian igualmente. La utilización de nuestra propuesta está orientada a

G. Navarro-Arribas; J. Garcia-Alfaro; O. Mula-Valls; J. Herrera-Joancomartí

259

Intact cluster and chordate-like expression of ParaHox genes in a sea star  

PubMed Central

Background The ParaHox genes are thought to be major players in patterning the gut of several bilaterian taxa. Though this is a fundamental role that these transcription factors play, their activities are not limited to the endoderm and extend to both ectodermal and mesodermal tissues. Three genes compose the ParaHox group: Gsx, Xlox and Cdx. In some taxa (mostly chordates but to some degree also in protostomes) the three genes are arranged into a genomic cluster, in a similar fashion to what has been shown for the better-known Hox genes. Sea urchins possess the full complement of ParaHox genes but they are all dispersed throughout the genome, an arrangement that, perhaps, represented the primitive condition for all echinoderms. In order to understand the evolutionary history of this group of genes we cloned and characterized all ParaHox genes, studied their expression patterns and identified their genomic loci in a member of an earlier branching group of echinoderms, the asteroid Patiria miniata. Results We identified the three ParaHox orthologs in the genome of P. miniata. While one of them, PmGsx is provided as maternal message, with no zygotic activation afterwards, the other two, PmLox and PmCdx are expressed during embryogenesis, within restricted domains of both endoderm and ectoderm. Screening of a Patiria bacterial artificial chromosome (BAC) library led to the identification of a clone containing the three genes. The transcriptional directions of PmGsx and PmLox are opposed to that of the PmCdx gene within the cluster. Conclusions The identification of P. miniata ParaHox genes has revealed the fact that these genes are clustered in the genome, in contrast to what has been reported for echinoids. Since the presence of an intact cluster, or at least a partial cluster, has been reported in chordates and polychaetes respectively, it becomes clear that within echinoderms, sea urchins have modified the original bilaterian arrangement. Moreover, the sea star ParaHox domains of expression show chordate-like features not found in the sea urchin, confirming that the dynamics of gene expression for the respective genes and their putative regulatory interactions have clearly changed over evolutionary time within the echinoid lineage.

2013-01-01

260

In para totale...una cosa da panico...sulla lingua dei giovani in Italia (In para totale...una cosa da panico...The Language of Young People in Italy).  

ERIC Educational Resources Information Center

Describes and analyzes the language of young people in Italy today. Particular focus is on the expressions using "para" (e.g., "in para totale" = to be very bored or worried) and the phrase "una cosa da panico" (something terrible or its opposite something wonderful). (CFM)

Marcato, Carla

1997-01-01

261

La política brasileña para los residuos sólidos urbanos. Los planteamientos de catadores y empresarios en sus páginas electrónicas  

Microsoft Academic Search

El gobierno brasileño señala la posibilidad de aprobar la política nacional para los residuos sólidos urbanos (PNRS). La propuesta del Proyecto de Ley 1991\\/07 está en trámite en la cámara de los diputados desde el año 1991. Los senadores mantuvieron una charla con los catadores, empresarios del reciclaje y empresarios de servicios de gestión de residuos sólidos urbanos para conocer

Fábio Fonseca Figueiredo

2008-01-01

262

Gastric perforation: a late complication of abdominal radiation for para-aortic lymph node metastasis from cervical squamous carcinoma.  

PubMed

Gastric perforation was found at laparotomy for acute abdominal pain in a woman treated with pelvic and abdominal radiation for squamous cell carcinoma of the uterine cervix metastatic to the para-aortic nodes. This case may provide additional evidence suggesting that risks involved in para-aortic radiation may outweigh the benefits. PMID:6655724

Dini, M M; Miller, M

1983-12-01

263

Gastric Perforation: A Late Complication of Abdominal Radiation for Para-Aortic Lymph Node Metastasis From Cervical Squamous Carcinoma  

PubMed Central

Gastric perforation was found at laparotomy for acute abdominal pain in a woman treated with pelvic and abdominal radiation for squamous cell carcinoma of the uterine cervix metastatic to the para-aortic nodes. This case may provide additional evidence suggesting that risks involved in para-aortic radiation may outweigh the benefits.

Dini, Morteza M.; Miller, Madeline

1983-01-01

264

EVALUATION OF PARA-DICHLOROBENZENE EMISSIONS FROM SOLID MOTH REPELLANT AS A SOURCE OF INDOOR AIR POLLUTION  

EPA Science Inventory

Mothcakes made of para-dichlorobenzene have been widely available for the general population to be used as a moth repellant to protect garments from insect damage. Usually, a mothcake is expected to last for weeks or even months during which the para-dichlorobenzene emits slowly ...

265

Herramienta de simulación interactiva y de bajo coste para el desarrollo de laboratorios virtuales de comunicaciones ópticas  

Microsoft Academic Search

En el ámbito académico, los laboratorios virtuales constituyen una solución pedagógica muy adecuada para aquellos casos donde resulta difícil poder disponer de recursos de laboratorio costosos. En este artículo se exponen resultados preliminares de la implementación de una plataforma de simulación interactiva para la enseñanza de materias relacionadas con las comunicaciones ópticas. Tras el primer año de aplicación de esta

Francisco Ramos Pascual

266

LA PARTICIPACIÓN Y SU IMPORTANCIA PARA EL DESARROLLO CULTURAL EN LA COMUNIDAD DE GASTÓN EN EL MUNICIPIO DE MAJIBACOA  

Microsoft Academic Search

La participación es un elemento indispensable que hace posible poner a prueba y desarrollar las capacidades humanas y estructuras, para desde la comunidad producir cultura para esta. Así se convierte en el elemento que posibilita un verdadero desarrollo endógeno en tanto proceso de cambio y transformación. Al proporcionar cauces de participación sociocultural, se estimula el desarrollo de determinadas relaciones y

Ana Margarita Gómez Aguilera; Rafaela Macías Reyes

2012-01-01

267

Comienza la construcción de instalación patrocinada por el NCI en Puerto Rico para realizar estudios clínicos sobre el cáncer  

Cancer.gov

El gobierno de Puerto Rico ha destinado $196 millones de dólares para construir un hospital oncológico de 287 000 pies cuadrados en San Juan, que contará con 96 camas. El nuevo hospital es el primero en su clase en la región caribeña y en él se llevarán a cabo tratamientos para el cáncer y estudios clínicos.

268

EVALUATION OF PARA-DICHLOROBENZENE EMISSIONS FROM SOLID MOTH REPELLANT AS A SOURCE OF INDOOR AIR POLLUTION  

EPA Science Inventory

The paper reports results of dynamic and static chamber tests to evaluate para-dichlorobenzene emission rates from mothcakes. he data were analyzed by a model that assumes that the para-dichlorobenzene emission from mothcakes is a temperature-sensitive sublimation process. ull-sc...

269

SISTEMA DE INDICADORES PARA LA EVALUACIÓN DE LA APLICACIÓN DEL SISTEMA DE GESTIÓN AMBIENTAL EN EMPRESAS CONSTRUCTORAS  

Microsoft Academic Search

Se tuvo como objetivo la propuesta de un sistema de indicadores para la evaluación de la aplicación del Sistema de Gestión Ambiental en empresas constructoras y la elaboración de un software para el procesamiento de los mismos, que contribuya a elevar la eficacia de la evaluación del desempeño ambiental y los resultados de las organizaciones de este tipo. Este sistema

Ninfa del Carmen Moncada Serrano

2012-01-01

270

Molecular characterization of neurally expressing genes in the para sodium channel gene cluster of Drosophila  

SciTech Connect

To elucidate the mechanisms regulating expression of para, which encodes the major class of sodium channels in the Drosophila nervous system, we have tried to locate upstream cis-acting regulatory elements by mapping the transcriptional start site and analyzing the region immediately upstream of para in region 14D of the polytene chromosomes. From these studies, we have discovered that the region contains a cluster of neurally expressing genes. Here we report the molecular characterization of the genomic organization of the 14D region and the genes within this region, which are: calnexin (Cnx), actin related protein 14D (Arp14D), calcineurin A 14D (CnnA14D), and chromosome associated protein (Cap). The tight clustering of these genes, their neuronal expression patterns, and their potential functions related to expression, modulation, or regulation of sodium channels raise the possibility that these genes represent a functionally related group sharing some coordinate regulatory mechanism. 76 refs., 11 figs.

Hong, Chang-Sook; Ganetzky, B. [Univ. of Wisconsin, Madison, WI (United States)

1996-03-01

271

H2CS abundances and ortho-to-para ratios in interstellar clouds  

NASA Technical Reports Server (NTRS)

Several H2CS ortho and para transitions have been observed toward interstellar molecular clouds, including cold, dark clouds and star-forming regions. H2CS fractional abundances f(H2CS) about 1-2 10 to the -9th relative to molecular hydrogen toward TMC-1, Orion A, and NGC 7538, and about 5 10 to the -10th for L134N are derived. The H2CS ortho-to-para ratios in TMC-1 are about 1.8 toward the cyanopolyyne peak and the ammonia peak, which may indicate the thermalization of H2CS on 10 K grains. A ratio of about 3, the statistical value, for Orion (3N, 1E) and NGC 7538 is derived, while a value of about 2 for Orion (KL) is found.

Minh, Y. C.; Irvine, W. M.; Brewer, M. K.

1991-01-01

272

Para-aortic lymph node metastasis in malignant dysgerminoma of the ovary.  

PubMed

Dysgerminomas comprise approximately 2-5% of all ovarian malignancies and mostly affect young adolescent women. Primary comprehensive surgery and adjuvant chemotherapy consisting of bleomycin, etoposide, and cisplatin (BEP) are the current recommended treatment options, the latter reserved for advanced stages (FIGO II-IV). We report two patients aged 20 and 26 years who presented with an initial FIGO stage IA, but inadequately assessed. Both were subsequently diagnosed with recurrent malignant dysgerminoma and para-aortic lymph node metastasis. Neither had received comprehensive staging at initial surgery nor adjuvant radio or chemotherapy. Both needed extensive surgery and multiagent chemotherapy for survival and belong to the small percentage of FIGO IA dysgerminoma patients showing a relapse. Comprehensive initial surgery including systematic para-aortic lymphadenectomy and adjuvant chemotherapy at tertiary referral centers is needed to minimize the treatment burden. PMID:19900144

Kasenda, Benjamin; Harter, Philipp; Hirsch, Tobias; Ast, Alexander; Buhrmann, Christine; Glaser, Florian; Du Bois, Andreas

2009-01-01

273

Solid and liquid heat capacities of n-alkyl para-aminobenzoates near the melting point.  

PubMed

The expression that relates the ideal mole fraction solubility of a crystalline compound to physicochemical properties of the compound includes a term involving the difference in the heat capacities of the solid and liquid forms of the solute, delta Cp. There are two alternate conventions which are employed to eliminate this term. The first assumes that the term involving delta Cp, or delta Cp itself, is zero. The alternate assumption assigns the value of the entropy of fusion to the differential heat capacity. The relative validity of these two assumptions was evaluated using the straight-chain alkyl para-aminobenzoates as test compounds. The heat capacities of the solid and liquid forms of each of the para-aminobenzoates, near the respective melting point, were determined by differential scanning calorimetry. The data lead one to conclude that the assumption that the differential heat capacity is not usually negligible and is better approximated by the entropy of fusion. PMID:2293215

Neau, S H; Flynn, G L

1990-11-01

274

Action spectra for ultraviolet photosensitized killing of mammalian cells by misonidazole and para-nitroacetophenone  

SciTech Connect

Chinese hamster fibroblasts in monolayer culture were exposed to ulraviolet radiation at 313, 334, 365, 380, and 405 nm in the presence of either misonidazole or para-nitroacetophenone, drugs which act as both photosensitizers and radiosensitizers of cell killing. Survival was measured by a colony-forming assay. The resulting action spectra for cell death photosensitized by the drugs (the reciprocals of the exposures required at each wavelength to reduce cell survival to a given level) closely match their absorption spectra over a range of three orders of magnitude. These results demonstrate that cells can be killed upon excitation of misonidazole or para-nitroacetophenone in the absence of any other types of energy deposition or biomolecular damage.

Fisher, G.J. (Centre Hospitalier Universitaire, Quebec, Canada); Sutherland, B.M.; Sutherland, J.C.

1983-05-01

275

Incentivos para atraer y retener personal de salud de zonas rurales del Per?: un estudio cualitativo  

PubMed Central

El objetivo fue identificar incentivos de atracción y retención en zonas rurales y distantes de Ayacucho, Perú. Fueron realizadas entrevistas en profundidad con 80 médicos, enfermeras, obstetras y técnicos (20 por grupo) de las zonas más pobres y con 11 funcionarios. No existen políticas sistemáticas de atracción y retención de personal de salud en Ayacucho. Los principales incentivos, en orden de importancia, fueron mejoras salariales, oportunidades de formación y capacitación, estabilidad laboral y nombramiento, mejoras en infraestructura y equipos, e incremento del personal. Se mencionaron también mejoras en la vivienda y alimentación, mayor cercanía con la familia y reconocimiento por el sistema de salud. Existen coincidencias y singularidades entre los distintos grupos sobre los incentivos clave para estimular el trabajo rural, que deben considerarse al diseñar políticas públicas. Las iniciativas del Estado deben comprender procesos rigurosos de monitoreo y evaluación, para asegurar que las mismas tengan el impacto deseado.

Huicho, Luis; Canseco, Francisco Diez; Lema, Claudia; Miranda, J. Jaime; Lescano, Andres G.

2014-01-01

276

Development of an integrated remote monitoring technique and its application to para-stressing bridge system  

NASA Astrophysics Data System (ADS)

Bridge monitoring system via information technology is capable of providing more accurate knowledge of bridge performance characteristics than traditional strategies. This paper describes not only an integrated Internet monitoring system that consists of a stand-alone monitoring system (SMS) and a Web-based Internet monitoring system (IMS) for bridge maintenance but also its application to para-stressing bridge system as an intelligent structure. IMS, as a Web-based system, is capable of addressing the remote monitoring by introducing measuring information derived from SMS into the system through Internet or intranet connected by either PHS or LAN. Moreover, the key functions of IMS such as data management system, condition assessment, and decision making with the proposed system are also introduced in this paper. Another goal of this study is to establish the framework of a para-stressing bridge system which is an intelligent bridge by integrating the bridge monitoring information into the system to control the bridge performance automatically.

Miyamoto, Ayaho; Motoshita, Minoru; Casas, Joan R.

2013-12-01

277

Avaliação de fontes de amônia para o tratamento de fenos de gramíneas tropicais. 2. Compostos nitrogenados  

Microsoft Academic Search

RESUMO - Este estudo foi desenvolvido para se avaliarem as alterações nos conteúdos de compostos nitrogenados dos fenos de braquiária decumbens ( Brachiaria decumbnes Stapf) e jaraguá (Hyparrhenia rufa Ness Stapf) não-tratados, tratados com uréia (U - 5,4% da MS), uréia (UL - 5,4% da MS) mais labe-labe (Lablab purpureus L. Sweet, cv. Highworth-3,0% da MS) ou amônia anidra (NH3

Ricardo Andrade Reis; Luis Roberto de Andrade Rodrigues; Kléber Tomás de Resende; João Ricardo Alves Pereira; Ana Cláudia Ruggieri

2001-01-01

278

Lanzamiento del estudio de tratamiento personalizado para el cáncer de seno  

Cancer.gov

Hoy se inició el Estudio de Asignación de Opciones Individualizadas de Tratamiento (Trial Assigning IndividuaLized Options for Treatment (Rx), o TAILORx, el cual evaluará si los genes que están frecuentemente asociados con el riesgo de recurrencia entre las mujeres con cáncer de seno en etapa inicial pueden ser utilizados para asignar a las pacientes el tratamiento más adecuado y efectivo. Preguntas y respuestas

279

Desarrollo y Propiedades Psicométricas de la Escala de Autoeficacia para la Depresión en Adolescentes (EADA)  

Microsoft Academic Search

Self-efficacy questionnaires used with adolescents are mostly youth-adapted adult measures or scales developed to assess general perceived self-efficacy. The purpose of this study was to develop and assess the psychometric properties of the Escala de Autoeficacia para la Depresión en Adolescentes (EADA). Additionally, the Emotional Self-efficacy subscale from the Self-Efficacy Questionnaire for Children and the Children's Depression Inventory-Short Version were

MIRELLA DÍAZ-SANTOS; EDUARDO CUMBA-AVILÉS; GUILLERMO BERNAL; CARMEN RIVERA-MEDINA

2008-01-01

280

Electrochemical intercalation of sodium ions into poly( para-phenylene) in carbonate-based electrolytes  

Microsoft Academic Search

Electrochemical intercalation of sodium ions into poly(para-phenylene) (PPP) has been carried out in NaClO4—carbonate electrolytes (EC, PC and their mixture in the volumic ratio of 1\\/1). The same electrochemical behavior has been observed in the three electrolytes. The galvanostatic curves exhibit potential slope changes which are characteristic of multiphase system; this behavior is confirmed by cyclic voltammetry. Our experimental conditions

M. Dubois; J. Ghanbaja; D. Billaud

1997-01-01

281

Projeto do sistema anti-ressonante da fiação dos transdutores para o detector Mario Schenberg  

NASA Astrophysics Data System (ADS)

O detector de ondas gravitacionais Mario Schenberg está sendo projetado e construído pelo grupo Gráviton. Sua construção está ocorrendo no Laboratório de Estado Sólido e Baixas Temperaturas (LESBT) da Universidade de São Paulo, na cidade de São Paulo. Esse detector possui uma massa ressonante esférica de cobre-alumínio, com 65 cm de diâmetro, pesando aproximadamente 1150 Kg, suspensa por um sistema de isolamento vibracional, que se encontra em fase de testes preliminares. A real eficácia desse sistema, entretanto, só poderá ser comprovada quando o detector estiver aparelhado com, pelo menos, um transdutor eletromecânico de altíssima sensibilidade acoplado à massa ressonante. Neste momento, não só este sistema de isolamento vibracional será posto em teste, como o do projeto da fiação que transporta os sinais de microondas até os transdutores e destes para a pré-amplificação. Apesar dessa fiação ter sido projetada para não apresentar nenhum contato com a superfície esférica da antena, de maneira a não haver nenhuma transmissão de ruído vibracional do laboratório para esta, deve-se minimizar o ruído microfônico produzido nessa fiação por oscilações mecânicas, uma vez que ela não utiliza nenhum sistema de isolamento vibracional. Com o intuito de resolver este problema, projetamos uma estrutura, formada por pequenos cilindros conectados por barras, a qual não terá nenhuma ressonância mecânica na faixa de freqüências de interesse para detecção (3000 - 3400 Hz). Desta forma, as vibrações nessa faixa não serão amplificadas. O projeto foi feito usando iterativamente, de maneira a otimizar os resultados obtidos, o programa de elementos finitos Msc/Nastran. Através de simulações feitas neste programa, determinamos os parâmetros geométricos ideais a serem utilizados, os quais proporcionam a maior região espectral de interesse livre de ressonâncias.

Vieira, S. J.., Jr.; Melo, J. L.

2003-08-01

282

Diffusion Monte Carlo study of the equation of state of solid para- H2  

Microsoft Academic Search

The diffusion Monte Carlo method is used to exactly solve the N -body Schroedinger equation for a system of para- H2 molecules at different densities described as pointlike particles interacting via an effective potential. We compare the results obtained using two of the most used model interactions, i.e., the Silvera-Goldman and the Buck potentials in order to assess their validity.

Francesco Operetto; Francesco Pederiva

2006-01-01

283

Acute renal failure following para-phenylenediamine (PPD) poisoning: a case report and review.  

PubMed

We report a case of systemic poisoning with para-phenylenediamine (PPD) presenting with characteristic features of severe angioneurotic edema, rhabdomyolysis and intravascular hemolysis with hemoglobinuria culminating in acute renal failure. Though rare in western countries, such poisoning is not uncommon in East Africa, Indian subcontinent and Middle East countries. We discuss here the clinical features and key management issues of systemic PPD poisoning. PMID:15354985

Anuradha, S; Arora, Sandeep; Mehrotra, S; Arora, A; Kar, P

2004-05-01

284

Contraluminal para-aminohippurate (PAH) transport in the proximal tubule of the rat kidney  

Microsoft Academic Search

In order to study the specificity for contraluminal para-aminohippurate (PAH) transport, the inhibitory potency of aliphatic dicarboxylates on3H-PAH influx, as well as the inhibitory effect on35SO42-- and3H-succinate influx, from the interstitium into cortical tubular cells in situ has been determined. The following was found:1.Testing a homologous series of dicarboxylates-ranging from the 2 C oxalate to the 10 C sebacate —

K. J. Ullrich; G. Rumrich; G. Fritzsch; S. Klöss

1987-01-01

285

Diastereoselective phenol para-alkylation: access to a cross-conjugated cyclohexadienone en route to resiniferatoxin.  

PubMed

We document a route for the synthesis of a densely functionalized spiro-fused 2,5-cyclohexadienone as an intermediate for the synthesis of resineferatoxin. The strategy is based on an unprecedented diastereoselective, intramolecular phenol para-alkylation to a cross-conjugated cyclohexadienone. In the course of these synthetic studies we developed rapid access to a chiral nitrile possessing a quaternary stereocenter and disclose an unusual acetal rearrangement from a dioxane, which favors the corresponding dioxepane. PMID:15524486

Ritter, Tobias; Zarotti, Pablo; Carreira, Erick M

2004-11-11

286

Anomalous NMR Line Shapes in Solid Ordered OrthoHydrogen and Para-Deuterium  

Microsoft Academic Search

Some highly anomalous features have been observed in the low-temperature NMR spectrum of high-purity (> 99% J=1), solid para-deuterium. The intensity of the low-frequency side of the Pake doublet is enhanced and that of the high-frequency side reduced, sometimes becoming negative, corresponding to an emission of power. The anomaly is particularly pronounced and of the opposite sign for the I=2

Walter N. Hardy; A. John Berlinsky

1973-01-01

287

Microsystems for determining the heterogeniety of head and neck cancer cell populations by para-magnetophoresis  

Microsoft Academic Search

This paper is focused on the design, fabrication and characterization of a continuous flow magnetophoretic microseparator for the separation of selectively tagged cells using para-magnetophoresis. The microseparator was characterized experimentally using head and neck cells lines 212LN and 686LN-M4E as a case study. The microfluidic separation system can separate the selectively tagged cancer cells depending on their membrane protein expression

Y. Jung; D. Wang; G. Chen; D. Shin; K. H. Han; A. B. Frazier

2009-01-01

288

Significado de los cambios en los senos: Guía para la salud de la mujer  

Cancer.gov

Información sobre cambios o padecimientos específicos de los senos y cómo se detectan, diagnostican y tratan estos cambios. Aquí se explica que si bien la mayoría de los cambios en los senos no son cancerosos, estos deben ser examinados por un médico. También se ofrece información sobre los pasos a seguir después de un resultado anormal de una mamografía y se incluye una lista de preguntas para el doctor.

289

Significado de los cambios en los senos: Guía para la salud de la mujer  

Cancer.gov

E-book que describe los cambios o padecimientos específicos de los senos e incluye información sobre cómo se detectan, diagnostican y tratan estos cambios. Aquí se explica que si bien la mayoría de los cambios en los senos no son cancerosos, estos deben ser examinados por un médico. También se ofrece información sobre los pasos a seguir después de un resultado anormal de una mamografía y se incluye una lista de preguntas para el doctor.

290

Para-sexiphenyl-CdSe\\/ZnS nanocrystal hybrid light emitting diodes  

Microsoft Academic Search

CdSe\\/ZnS core\\/shell nanocrystals (NCs) are integrated into para-sexiphenyl (p-6P) based hybrid light emitting diodes, to obtain green and red emission in addition to blue emission originated from p-6P. For the active region of the devices, ultrathin layers of p-6P and NCs are deposited by hot wall epitaxy and spin casting, respectively, resulting in current-voltage characteristics with small leakage currents and

C. Simbrunner; G. Hernandez-Sosa; E. Baumgartner; G. Hesser; J. Roither; W. Heiss; H. Sitter

2009-01-01

291

Revision of Vertical Banded Gastroplasty Complicated by a Large Para-esophageal Hernia  

Microsoft Academic Search

Patients who have undergone bariatric surgery and present with upper abdominal symptoms pose a diagnostic and management challenge.\\u000a This is a case report of a 53-year-old lady who presented a number of years after vertical banded gastroplasty with upper\\u000a abdominal pain and weight gain. Radiological investigation demonstrated a large para-esophageal hernia including the stapled\\u000a area of the stomach, but with

Mansoor Khan; Fred Lee; Roger Ackroyd

2010-01-01

292

Terahertz absorption spectrum of para and ortho water vapors at different humidities at room temperature  

Microsoft Academic Search

Terahertz time-domain spectroscopy has been used to measure the absorption of water vapor in 0.2-2.4 THz range from low to high humidity at room temperature. The observed absorption lines are due to the water molecular rotations in the ground vibrational state. We find that the absorption strength of para transitions increases as humidity increases, while the absorption strength of ortho

X. Xin; H. Altan; A. Saint; D. Matten; R. R. Alfano

2006-01-01

293

New High Temperature Lithium Para-Toluene Sulfonate (LIPTSA) Salt for Rechargeable Batteries  

Microsoft Academic Search

Lithium para-toluene sulfonate [LIPTSA] was used for lithium rechargeable batteries, with poly(methyl methacrylate) [PMMA] as the base material. Tri block copolymer of PEO-PPO-PEO was used to increase the solubility of lithium salts in PMMA matrix. FTIR, TGA, XRD, Impedance spectroscopy & SEM were used for characterizations and morphological studies. LIPTSA salt is stable up to 375°C. The highest room temperature

Sreejith K R; Akhil Kumar Sen

2012-01-01

294

A rapid HPLC method for determination of Sudan dyes and Para Red in red chilli pepper  

Microsoft Academic Search

A rapid high-performance liquid chromatography (HPLC) system consisting of an ultraviolet-visible (UV–VIS) detector was developed for the separation and determination of Sudan dyes (I, II, III, and IV) and Para Red in red chilli peppers. The chromatographic separation was achieved on a reverse phase C18 column with isocratic elution, using a mobile phase of acetonitrile\\/methanol (80:20, v\\/v); detector was set

Erdal Erta?; Hayrettin Özer; Cesarettin Alasalvar

2007-01-01

295

Determination of Sudan Dyes and Para Red in Duck Muscle and Egg by UPLC  

Microsoft Academic Search

A simple, sensitive and reliable UPLC method was developed and validated for the simultaneous determination of six Sudan dyes\\u000a (Sudan Red G, Sudan I, II, III, Sudan Red 7B, Sudan IV) and Para Red in duck muscle and egg samples. Samples were extracted with acetonitrile, then the extract was dried under\\u000a rotary evaporation and dissolved in acetonitrile\\/0.1% formic acid (85:15,

Cun Li; Ting Yang; Yan Zhang; Yin-Liang Wu

2009-01-01

296

UPLC-ESI-MS\\/MS analysis of Sudan dyes and Para Red in food  

Microsoft Academic Search

An analytical method for the simultaneous determination of Sudan dyes (Sudan Red G, Sudan I, Sudan II, Sudan III, Sudan Red 7B and Sudan IV) and Para Red in food by ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-ESI-MS\\/MS) was developed. Samples were extracted with acetonitrile, and water added into the extract. The supernatant was analysed by UPLC-MS\\/MS after refrigeration and

C. Li; Y. L. Wu; J. Z. Shen

2010-01-01

297

Um Processador Construtivista na Web para documentos anotados (PcWDa)  

Microsoft Academic Search

Resumo A notacao XML, cada vez mais, desempenha um papel im- portante na representacao textual da informacao estruturada ou semi- estruturada, sendo a norma mais vulgarizada para marcacao de do- cumentos. Torna-se por isso indispensavel a existencia de ferramentas que possibilitem desenvolver(editar e validar) eficientemente documen- tos XML. Neste artigo pretende-se discutir a especificacao e o desenvolvimento de uma dessas

Mariana Isabel Ferreira; Sandra Cristina Lopes; Pedro Rangel Henriques

298

Surgical resection of a solitary para-aortic lymph node metastasis from hepatocellular carcinoma.  

PubMed

Lymph node (LN) metastases from hepatocellular carcinoma (HCC) are considered uncommon. We describe the surgical resection of a solitary para-aortic LN metastasis from HCC. A 65-year-old Japanese man with B-type liver cirrhosis was admitted for the evaluation of a liver tumor. He had already undergone radiofrequency ablation, transcatheter arterial chemoembolization, and percutaneous ethanol injection therapy for HCC. Despite treatment, viable regions remained in segments 4 and 8. We performed a right paramedian sectionectomy with partial resection of the left paramedian section of the liver. Six months later, serum concentrations of alpha-fetoprotein (189 ng/mL) and PIVKA-2 (507 mAU/mL) increased. Enhanced computed tomography of the abdomen revealed a tumor (20 mm in diameter) on the right side of the abdominal aorta. Fluorine-18 fluorodeoxyglucose positron emission tomography revealed an increased standard uptake value. There was no evidence of recurrence in other regions. Esophagogastroduodenoscopy and colonoscopy revealed no malignant tumor in the gastrointestinal tract. Para-aortic LN metastasis from HCC was thus diagnosed. We performed lymphadenectomy. Histopathological examination revealed that the tumor was largely necrotic, with poorly differentiated HCC on its surface, which confirmed the suspected diagnosis. After 6 mo tumor marker levels were normal, with no evidence of recurrence. Our experience suggests that a solitary para-aortic LN metastasis from HCC can be treated surgically. PMID:22736929

Ueda, Junji; Yoshida, Hiroshi; Mamada, Yasuhiro; Taniai, Nobuhiko; Mineta, Sho; Yoshioka, Masato; Kawano, Youichi; Shimizu, Tetsuya; Hara, Etsuko; Kawamoto, Chiaki; Kaneko, Keiko; Uchida, Eiji

2012-06-21

299

Comparação de modelos para o cálculo de perturbações orbitais devidas à maré terrestre  

NASA Astrophysics Data System (ADS)

Aplicações recentes de satélites artificiais com finalidades geodinâmicas requerem órbitas determinadas com bastante precisão. Em particular marés terrestres influenciam o potencial terrestre causando perturbações adicionais no movimento de satélites artificiais, as quais tem sido medidas por diversos processos. A atração exercida pela lua e pelo sol sobre a terra produz deslocamentos elásticos em seu interior e uma protuberância em sua superfície. O resultado é uma pequena variação na distribuição da massa na terra, consequentemente no geopotencial. As perturbações nos elementos orbitais de satélites artificiais terrestres devidas a maré terrestre podem ser estudadas a partir das equações de Lagrange, considerando-se um conveniente potencial. Por outro lado, como tem sido feito pelo IERS, as mudanças induzidas pela maré terrestre no geopotencial podem ser convenientemente modeladas como variações nos coeficientes Cnm e Snm do geopotencial. As duas teorias ainda não foram comparados para um mesmo satélite. Neste trabalho são apresentadas e comparadas as variações de longo período e seculares nas perturbações orbitais devidas à maré terrestre, calculadas por um modelo simples, o de Kozai, e pelo modelo do IERS. Resultados preliminares mostram, para os satélites SCD2 e CBERS1, e para a Lua em movimento elíptico e precessionando, as perturbações seculares no argumento do perigeu e na longitude do nodo ascendente.

Vieira Pinto, J.; Vilhena de Moraes, R.

2003-08-01

300

Otimização de procedimento de manobra para indução de reentrada de um satélite retornável  

NASA Astrophysics Data System (ADS)

Veículos espaciais que retornam à Terra passam por regimes de velocidade e condições de vôo distintos. Estas diferenças dificultam sua concepção aerodinâmica e o planejamento de seu retorno. A partir de uma proposta de um veículo orbital retornável (satélite SARA, em desenvolvimento no IAE/CTA) para realização de experimentos científicos e tecnológicos em ambiente de baixa gravidade, surge a necessidade de realizarem-se estudos considerando-se os aspectos relativos à sua aerodinâmica. Após o lançamento, o veículo deve permanecer em órbita pelo tempo necessário para a condução de experimentos, sendo depois direcionado à Terra e recuperado em solo. A concepção aerodinâmica é de importância para o vôo em suas diversas fases e deve considerar aspectos relativos à estabilização Aerodinâmica e ao arrasto atmosférico, sendo este último de importância crucial na análise do aquecimento a ser enfrentado. A manobra de retorno inclui considerações sobre as condições atmosféricas e dinâmica de reentrada, devendo ser calculada de forma mais precisa possível. O trabalho proposto avalia estudos da dinâmica de vôo de um satélite recuperável considerando aspectos relativos à determinação orbital com GPS, técnica utilizada com sucesso na CONAE, e seu comportamento aerodinâmico em vôo balístico de retorno, com ênfase em sua fase de reentrada atmosférica. Busca-se otimizar a manobra de reentrada de tal forma que a utilização do sistema GPS garanta minimizar a área de impacto com o solo.

Schulz, W.; Suarez, M.

2003-08-01

301

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

NASA Astrophysics Data System (ADS)

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

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

2000-04-01

302

An incidentally discovered asymptomatic para-aortic paraganglioma with Peutz-Jeghers syndrome.  

PubMed

Peutz-Jeghers syndrome (PJS) is an autosomal dominant inherited disorder characterized by mucocutaneous melanin pigmentation and gastrointestinal (GI) tract hamartomatous polyps and an increased risk of malignancy. In addition to polyposis, previous studies have reported increased risk of GI and extraGI malignancies in PJS patients, compared with that of the general population. The most common extraintestinal malignancies reported in previous studies are pancreatic, breast, ovarian and testicular cancers.We report the case of a 17-year-old boy who presented with generalized weakness, recurrent sharp abdominal pain and melena, had exploratory laparotomy and ileal resection for ileo-ileal intussusception. Pigmentation of the buccal mucosa was noted. An abdominal computed tomography scan (CT) revealed multiple polyps in small bowel loops. Gastroscopy revealed multiple dimunitive polyps in stomach and pedunculated polyp in duodenum. Colonoscopy revealed multiple colonic polyps. Pathological examination of the polyps confirmed hamartomas with smooth muscle arborization, compatible with Peutz-Jeghers polyps. CT scan guided left para-aortic lymph node biopsy revealed the characteristic features of extra-adrenal para-aortic paraganglioma. Although cases of various GI and extra GI malignancies in PJS patients has been reported, the present case appears to be the first in literature in which the PJS syndrome was associated with asymptomatic extraadrenal para-aortic paraganglioma. Patients with PJS should be treated by endoscopic or surgical resection and need whole-body screening. PMID:23150026

Butt, Nazish; Salih, Mohammad; Khan, Mohammad Rizwan; Ahmed, Rashida; Haider, Zishan; Shah, Syed Hasnain Ali

2012-01-01

303

Transoral, retromolar, para-tonsillar approach to the styloid process in 6 patients with Eagle's syndrome  

PubMed Central

Objectives: Eagle’s syndrome is caused by an elongated or mineralised styloid process and characterised by facial and pharyngeal pain, odynophagia and dysphagia. Diagnosis is based on clinical findings. However radiologic imaging, like panoramic radiograph, helps to confirm the diagnosis. There are different treatments of the Eagle’s syndrome. Anti-inflammatory medication (carbamazepime, corticosteroids) and/or surgical interventions are established. The aim of the different surgical techniques is to resect the elongated styloid process near the skull base. Study Design: A transoral, retromolar, para-tonsillar approach was performed to expose and resect the elongated calcified styloid process in a consecutive series of six patients. The use of different angled ring curettes, generally used in hypophysis surgery, facilitated the preparation of the styloid process through the surrounding tissue to the skull base, without a compromise to the surrounding tissue. Clinical examinations were performed pre- and postoperatively (3 month and after 1 year after surgery) in all patients. Results: No intra- or postoperative complications were observed. The hypophysis ring curettes facilitated the preparation of the styloid process to the skull base. Conclusions: The transoral, retromolar, para-tonsillar approach is a secure and fast method to resect an elongated symptomatic styloid process. Side effects of the classical transoral trans-tonsillar approach did not occur. Key words:Retromolar, para-tonsillar approach, Eagle syndrome, clinical features.

Eckert, Alexander W.; Scheller, Christian

2014-01-01

304

[Formation of para-Bombay phenotype caused by homozygous or heterozygous mutation of FUT1 gene].  

PubMed

This study was aimed to explore the molecular mechanisms for para-Bombay phenotype formation. The H antigen of these individuals were identified by serological techniques. The full coding region of alpha (1, 2) fucosyltransferase (FUT1) gene of these individuals was amplified by high-fidelity polymerase chain reaction (PCR). PCR product was identified by TOPO cloning sequencing. Analysis and comparison were used to explore the mechanisms of para-bombay phenotype formation in individuals. The results indicated that the full coding region of FUT1 DNA was successfully amplified by PCR and gel electrophoresis. DNA sequencing and analysis found that h1 (547-552delAG) existed in one chromosome and h4 (35C > T) existed in the other chromosome of NO.1 individual. Meantime, h1 (547-552delAG) was found in two chromosomes of NO.2 and NO.3 individual. It also means that FUT1 gene of NO.1 individual was h1h4 heterozygote, FUT1 gene of NO.2 and NO.3 individuals were h1h1 homozygote. It is concluded that homozygous and heterozygous mutation of FUT1 gene can lead to the formation of para-Bombay phenotype. PMID:24598677

Zhang, Jin-Ping; Zheng, Yan; Sun, Dong-Ni

2014-02-01

305

Fragrance material review on 1-(para-menthen-6-yl)-1-propanone.  

PubMed

A toxicologic and dermatologic review of 1-(para-Menthen-6-yl)-1-propanone when used as a fragrance ingredient is presented. 1-(para-Menthen-6-yl)-1-propanone is a member of the fragrance structural group Alkyl Cyclic Ketones. These fragrances can be described as being composed of an alkyl, R1, and various substituted and bicyclic saturated or unsaturated cyclic hydrocarbons, R2, in which one of the rings may include up to 12 carbons. Alternatively, R2 may be a carbon bridge of C2-C4 carbon chain length between the ketone and cyclic hydrocarbon. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 1-(para-Menthen-6-yl)-1-propanone were evaluated then summarized and includes physical properties, acute toxicity, skin irritation, and skin sensitization, data. A safety assessment of the entire Alkyl Cyclic Ketones will be published simultaneously with this document; please refer to Belsito et al. (2013) [Belsito, D., Bickers, D., Bruze, M., Calow, P., Dagli, M., Fryer, A.D., Greim, H., Miyachi, Y., Saurat, J.H., Sipes, I.G., 2013 A Toxicologic and Dermatologic Assessment of Alkyl Cyclic Ketones When Used as Fragrance Ingredients. Submitted with this manuscript.] for an overall assessment of the safe use of this material and all Alkyl Cyclic Ketones in fragrances. PMID:24246181

Scognamiglio, J; Letizia, C S; Api, A M

2013-12-01

306

Modeling, design, chiral aspects and role of para-substituents in aryloxypropranolamine based beta-blockers.  

PubMed

The conformation of the beta-blockers viz. metoprolol, atenolol, bisoprolol, betaxolol and celiprolol has been investigated using Perturbative Configuration Interaction of Localized Orbitals (PCILO) method. The conformational energy maps have been constructed for both the enantiomers (R and S) by rotating the molecule from the para-substituent end. The aryloxypropranolamine moiety adopts the same conformation for all antagonists. The graphical view of R- and S- form of these antagonists in the lowest energy conformation reveals that it is only in the S- form of beta-blockers, all the three functionalities--aromatic moiety, amino and beta-hydroxyl groups are available for interaction with beta-adrenoceptors. The para-substituents of the beta-blockers adopt a conformation which is perpendicular to the aryloxy moiety resulting in an L-shaped structure. The beta-antagonists possibly partition into the lipid bilayer through the para-substituents and the aryloxypropranolamine moiety containing the functionalities, thus, lies parallel to the plane of lipid bilayer for interaction with beta-adrenoceptors. Superimposition of S-bisoprolol in lowest energy conformation with the 3rd putative transmembranous segment of the beta-adrenoceptors reveals that the aromatic moiety, amino and beta-hydroxyl groups of antagonists are involved in interaction with the side chains of Trp-109, Asp-113 and Thr-110 respectively. This has been further substantiated by the interaction studies on the model systems. PMID:10549157

Nandel, F S; Dhaliwal, R K; Singh, B

1999-02-01

307

Theoretical study of the design of a catalyst for para to ortho hydrogen conversion  

NASA Technical Reports Server (NTRS)

The theory of Petzinger and Scalapino (1973) was thoroughly reviewed, and all of the basic equations for paramagnetic para to ortho hydrogen catalysis re-derived. There are only a few minor phase errors and errors of omission in the description of the theory. Three models (described by Petzinger and Scalapino) for the rate of para to ortho H2 catalysis were worked out, and uniform agreement obtained to within a constant factor of 2 pi. The analytical methods developed in the course of this study were then extended to two new models, which more adequately describe the process of surface catalysis including transfer of hydrogen molecules onto and off of the surface. All five equations for the para to ortho catalytic rate of conversion are described. The two new equations describe the catalytic rate for these models: H2 on the surface is a 2-D gas with lifetime tau; and H2 on the surface is a 2-D liquid undergoing Brownian motion (diffusion) with surface lifetime tau.

Coffman, Robert E.

1992-01-01

308

Atlas de aves: Un metodo para documentar distribucion y seguir poblaciones  

USGS Publications Warehouse

Los Atlas de Aves son proyectos nacionales o regionalies para trazar en mapas la distribucion en reproduccion de cada especie de ave. Ese procedimiento se esta usando en Europa, Australia, Nueva Zelanda, Norteamerica, y partes de Africa. El tama?o de los cuadrados varia de medio grado de latitud y Iongitud hasta 5 x 5 km. El trabajo de campo de cada proyecto exige aproxlmadamente cinco a?os, pero los aficionados pueden llevar a cabo la mayor parte del trabajo. Es posible almacenar los resultados en un computador personal. Hay muchos beneficios: (I) se presenta la distribucion corriente de las aves de la nacion, del estado, o de la Iocalidad; (2) se desarrolla nueva informacion especialmente sobre especies raras o en peligro; (3) se descubren areas que tienen una avlfauna sobresaliente o habitats raros y ayuda a su proteccion, (4) se documentan cambios de dlstribucion; (5) se pueden usar para documentar cambios de poblacion, especialmente en los tropicos donde otros metodos son mas dificiles de usar porque hay muchas especies y no hay muchos observadores calificados en la identificacion de sonidos de las aves; (6) son proyectos buenos de investigacion para estudiantes graduados; (7) los turistas y los jefes de excursiones de historia natural pueden contribuir con muchas informaciones

Robbins, C.S.; Dowell, B.A.; Dawson, D.K.

1988-01-01

309

Dynamic interplay of ParA with the polarity protein, Scy, coordinates the growth with chromosome segregation in Streptomyces coelicolor.  

PubMed

Prior to bacterial cell division, the ATP-dependent polymerization of the cytoskeletal protein, ParA, positions the newly replicated origin-proximal region of the chromosome by interacting with ParB complexes assembled on parS sites located close to the origin. During the formation of unigenomic spores from multi-genomic aerial hyphae compartments of Streptomyces coelicolor, ParA is developmentally triggered to form filaments along the hyphae; this promotes the accurate and synchronized segregation of tens of chromosomes into prespore compartments. Here, we show that in addition to being a segregation protein, ParA also interacts with the polarity protein, Scy, which is a component of the tip-organizing centre that controls tip growth. Scy recruits ParA to the hyphal tips and regulates ParA polymerization. These results are supported by the phenotype of a strain with a mutant form of ParA that uncouples ParA polymerization from Scy. We suggest that the ParA-Scy interaction coordinates the transition from hyphal elongation to sporulation. PMID:23536551

Ditkowski, Bartosz; Holmes, Neil; Rydzak, Joanna; Donczew, Magdalena; Bezulska, Martyna; Ginda, Katarzyna; Kedzierski, Pawel; Zakrzewska-Czerwi?ska, Jolanta; Kelemen, Gabriella H; Jakimowicz, Dagmara

2013-03-01

310

Functional expression of Drosophila para sodium channels. Modulation by the membrane protein TipE and toxin pharmacology.  

PubMed

The Drosophila para sodium channel alpha subunit was expressed in Xenopus oocytes alone and in combination with tipE, a putative Drosophila sodium channel accessory subunit. Coexpression of tipE with para results in elevated levels of sodium currents and accelerated current decay. Para/TipE sodium channels have biophysical and pharmacological properties similar to those of native channels. However, the pharmacology of these channels differs from that of vertebrate sodium channels: (a) toxin II from Anemonia sulcata, which slows inactivation, binds to Para and some mammalian sodium channels with similar affinity (Kd congruent with 10 nM), but this toxin causes a 100-fold greater decrease in the rate of inactivation of Para/TipE than of mammalian channels; (b) Para sodium channels are >10-fold more sensitive to block by tetrodotoxin; and (c) modification by the pyrethroid insecticide permethrin is >100-fold more potent for Para than for rat brain type IIA sodium channels. Our results suggest that the selective toxicity of pyrethroid insecticides is due at least in part to the greater affinity of pyrethroids for insect sodium channels than for mammalian sodium channels. PMID:9236205

Warmke, J W; Reenan, R A; Wang, P; Qian, S; Arena, J P; Wang, J; Wunderler, D; Liu, K; Kaczorowski, G J; Van der Ploeg, L H; Ganetzky, B; Cohen, C J

1997-08-01

311

ParA encoded on chromosome II of Deinococcus radiodurans binds to nucleoid and inhibits cell division in Escherichia coli.  

PubMed

Bacterial genome segregation and cell division has been studied mostly in bacteria harbouring single circular chromosome and low-copy plasmids. Deinococcus radiodurans, a radiation-resistant bacterium, harbours multipartite genome system. Chromosome I encodes majority of the functions required for normal growth while other replicons encode mostly the proteins involved in secondary functions. Here, we report the characterization of putative P-loop ATPase (ParA2) encoded on chromosome II of D. radiodurans. Recombinant ParA2 was found to be a DNA-binding ATPase. E. coli cells expressing ParA2 showed cell division inhibition and mislocalization of FtsZ-YFP and those expressing ParA2-CFP showed multiple CFP foci formation on the nucleoid. Although, in trans expression of ParA2 failed to complement SlmA loss per se, it could induce unequal cell division in slmAminCDE double mutant. These results suggested that ParA2 is a nucleoid-binding protein, which could inhibits cell division in E. coli by affecting the correct localization of FtsZ and thereby cytokinesis. Helping slmAminCDE mutant to produce minicells, a phenotype associated with mutations in the 'Min' proteins, further indicated the possibility of ParA2 regulating cell division by bringing nucleoid compaction at the vicinity of septum growth. PMID:23938382

Charaka, Vijaya Kumar; Mehta, Kruti P; Misra, H S

2013-09-01

312

Dynamic interplay of ParA with the polarity protein, Scy, coordinates the growth with chromosome segregation in Streptomyces coelicolor  

PubMed Central

Prior to bacterial cell division, the ATP-dependent polymerization of the cytoskeletal protein, ParA, positions the newly replicated origin-proximal region of the chromosome by interacting with ParB complexes assembled on parS sites located close to the origin. During the formation of unigenomic spores from multi-genomic aerial hyphae compartments of Streptomyces coelicolor, ParA is developmentally triggered to form filaments along the hyphae; this promotes the accurate and synchronized segregation of tens of chromosomes into prespore compartments. Here, we show that in addition to being a segregation protein, ParA also interacts with the polarity protein, Scy, which is a component of the tip-organizing centre that controls tip growth. Scy recruits ParA to the hyphal tips and regulates ParA polymerization. These results are supported by the phenotype of a strain with a mutant form of ParA that uncouples ParA polymerization from Scy. We suggest that the ParA–Scy interaction coordinates the transition from hyphal elongation to sporulation.

Ditkowski, Bartosz; Holmes, Neil; Rydzak, Joanna; Donczew, Magdalena; Bezulska, Martyna; Ginda, Katarzyna; Kedzierski, Pawel; Zakrzewska-Czerwinska, Jolanta; Kelemen, Gabriella H.; Jakimowicz, Dagmara

2013-01-01

313

Identification of an intact ParaHox cluster with temporal colinearity but altered spatial colinearity in the hemichordate Ptychodera flava  

PubMed Central

Background ParaHox and Hox genes are thought to have evolved from a common ancestral ProtoHox cluster or from tandem duplication prior to the divergence of cnidarians and bilaterians. Similar to Hox clusters, chordate ParaHox genes including Gsx, Xlox, and Cdx, are clustered and their expression exhibits temporal and spatial colinearity. In non-chordate animals, however, studies on the genomic organization of ParaHox genes are limited to only a few animal taxa. Hemichordates, such as the Enteropneust acorn worms, have been used to gain insights into the origins of chordate characters. In this study, we investigated the genomic organization and expression of ParaHox genes in the indirect developing hemichordate acorn worm Ptychodera flava. Results We found that P. flava contains an intact ParaHox cluster with a similar arrangement to that of chordates. The temporal expression order of the P. flava ParaHox genes is the same as that of the chordate ParaHox genes. During embryogenesis, the spatial expression pattern of PfCdx in the posterior endoderm represents a conserved feature similar to the expression of its orthologs in other animals. On the other hand, PfXlox and PfGsx show a novel expression pattern in the blastopore. Nevertheless, during metamorphosis, PfXlox and PfCdx are expressed in the endoderm in a spatially staggered pattern similar to the situation in chordates. Conclusions Our study shows that P. flava ParaHox genes, despite forming an intact cluster, exhibit temporal colinearity but lose spatial colinearity during embryogenesis. During metamorphosis, partial spatial colinearity is retained in the transforming larva. These results strongly suggest that intact ParaHox gene clustering was retained in the deuterostome ancestor and is correlated with temporal colinearity.

2013-01-01

314

Estudio de terapias dirigidas para el cáncer de seno estableció un modelo de estudios clínicos a nivel mundial  

Cancer.gov

Dos medicamentos de acción dirigida, diseñados para tratar una forma agresiva de cáncer de seno (mama), se pusieron a prueba en un estudio que incluyó a 8 000 participantes en 44 países. Si bien la finalidad del estudio fue ayudar a que los investigadores determinaran si el tratamiento combinado con trastuzumab y lapatinib para el tratamiento del cáncer de seno HER2 positivo en estado inicial era mejor que la terapia solo con trastuzumab, los resultados del estudio no indicaron que existan ventajas para las mujeres al recibir la combinación de fármacos de trastuzumab o lapatinib.

315

Identification and Characterization of Catabolic para-Nitrophenol 4-Monooxygenase and para-Benzoquinone Reductase from Pseudomonas sp. Strain WBC-3?  

PubMed Central

Pseudomonas sp. strain WBC-3 utilizes para-nitrophenol (PNP) as a sole source of carbon, nitrogen, and energy. In order to identify the genes involved in this utilization, we cloned and sequenced a 12.7-kb fragment containing a conserved region of NAD(P)H:quinone oxidoreductase genes. Of the products of the 13 open reading frames deduced from this fragment, PnpA shares 24% identity to the large component of a 3-hydroxyphenylacetate hydroxylase from Pseudomonas putida U and PnpB is 58% identical to an NAD(P)H:quinone oxidoreductase from Escherichia coli. Both PnpA and PnpB were purified to homogeneity as His-tagged proteins, and they were considered to be a monomer and a dimer, respectively, as determined by gel filtration. PnpA is a flavin adenine dinucleotide-dependent single-component PNP 4-monooxygenase that converts PNP to para-benzoquinone in the presence of NADPH. PnpB is a flavin mononucleotide-and NADPH-dependent p-benzoquinone reductase that catalyzes the reduction of p-benzoquinone to hydroquinone. PnpB could enhance PnpA activity, and genetic analyses indicated that both pnpA and pnpB play essential roles in PNP mineralization in strain WBC-3. Furthermore, the pnpCDEF gene cluster next to pnpAB shares significant similarities with and has the same organization as a gene cluster responsible for hydroquinone degradation (hapCDEF) in Pseudomonas fluorescens ACB (M. J. Moonen, N. M. Kamerbeek, A. H. Westphal, S. A. Boeren, D. B. Janssen, M. W. Fraaije, and W. J. van Berkel, J. Bacteriol. 190:5190-5198, 2008), suggesting that the genes involved in PNP degradation are physically linked.

Zhang, Jun-Jie; Liu, Hong; Xiao, Yi; Zhang, Xian-En; Zhou, Ning-Yi

2009-01-01

316

Identification and characterization of catabolic para-nitrophenol 4-monooxygenase and para-benzoquinone reductase from Pseudomonas sp. strain WBC-3.  

PubMed

Pseudomonas sp. strain WBC-3 utilizes para-nitrophenol (PNP) as a sole source of carbon, nitrogen, and energy. In order to identify the genes involved in this utilization, we cloned and sequenced a 12.7-kb fragment containing a conserved region of NAD(P)H:quinone oxidoreductase genes. Of the products of the 13 open reading frames deduced from this fragment, PnpA shares 24% identity to the large component of a 3-hydroxyphenylacetate hydroxylase from Pseudomonas putida U and PnpB is 58% identical to an NAD(P)H:quinone oxidoreductase from Escherichia coli. Both PnpA and PnpB were purified to homogeneity as His-tagged proteins, and they were considered to be a monomer and a dimer, respectively, as determined by gel filtration. PnpA is a flavin adenine dinucleotide-dependent single-component PNP 4-monooxygenase that converts PNP to para-benzoquinone in the presence of NADPH. PnpB is a flavin mononucleotide-and NADPH-dependent p-benzoquinone reductase that catalyzes the reduction of p-benzoquinone to hydroquinone. PnpB could enhance PnpA activity, and genetic analyses indicated that both pnpA and pnpB play essential roles in PNP mineralization in strain WBC-3. Furthermore, the pnpCDEF gene cluster next to pnpAB shares significant similarities with and has the same organization as a gene cluster responsible for hydroquinone degradation (hapCDEF) in Pseudomonas fluorescens ACB (M. J. Moonen, N. M. Kamerbeek, A. H. Westphal, S. A. Boeren, D. B. Janssen, M. W. Fraaije, and W. J. van Berkel, J. Bacteriol. 190:5190-5198, 2008), suggesting that the genes involved in PNP degradation are physically linked. PMID:19218392

Zhang, Jun-Jie; Liu, Hong; Xiao, Yi; Zhang, Xian-En; Zhou, Ning-Yi

2009-04-01

317

Comportamento da dose glandular versus contraste do objeto em mamografia: determinação de formalismo semi-empírico para diferentes combinações alvo-filtro  

Microsoft Academic Search

OBJETIVO: Verificar o efeito da mudança no contraste do objeto, tempo de exposição e dose de radiação quando diferentes espessuras de filtração de molibdênio (Mo) e ródio (Rh) são empregadas em mamógrafos. MATERIAIS E MÉTODOS: Realizaram-se medidas da exposição na entrada da pele com uma câmara de ionização para diferentes espessuras para os filtros de Mo e Rh. Para determinar

Gabriela Hoff; Carlos Eduardo de Almeida; Gary T. Barnes

2006-01-01

318

Multi-determination of Para red and Sudan dyes in egg by a broad specific antibody based enzyme linked immunosorbent assay  

Microsoft Academic Search

Para red and Sudan dyes (Sudan 1, 2, 3, 4, and Sudan G) have been proven to show the potential carcinogenic effect to human. This study first reported an indirect competitive immunoassay (ELISA) for simultaneous detection of the six red dyes in egg. Two immunogens of Para red were prepared by coupling the deoxidized Para red to carrier protein by

Xiang Cai Chang; Xiu Zhi Hu; Yan Qin Li; Yan Jiao Shang; Yan Zheng Liu; Gao Feng; Jian Ping Wang

2011-01-01

319

Diseño, análisis y manufactura de un sistema de fijación interna para tratamiento de fracturas en el primer metacarpiano  

Microsoft Academic Search

En la Universidad Central de Venezuela se está desarrollando un sistema intramedular bloqueado para\\u000atratamiento de fracturas diafisiarias en los huesos metacarpianos como una nueva alternativa para este tipo\\u000ade lesiones. El dispositivo es poco invasivo y permite movilidad temprana de la mano al paciente postoperado\\u000aacortando el tiempo de recuperación. En este trabajo se presentan los diferentes procesos que

Gabriela Contreras; Miguel Cerrolaza; Manuel Martínez; Nils Götzen

1970-01-01

320

A computa»c~ao numerica como ferramenta para o professor de F¶‡sica do Ensino Medio  

Microsoft Academic Search

A proposta deste trabalhoe apresentar ao professor de F¶‡sica do ensino medio uma forma de empregar recur- sos computacionais para esclarecer e aprofundar conceitos de F¶‡sica que s~ao explorados de forma limitada por n~ao se poder recorrer ao Calculo Diferencial e Integral. O p^endulo simplese usado como prototipo para o trata- mento sugerido. Mostramos que apenas com o aux¶‡lio de

Augusto Cesar; Claudio Gon; Marcus Vinicius; Tovar Costa

321

A Introdução de Astronomia Básica para Estudantes de 5 e 6 Séries do Ensino Fundamental  

NASA Astrophysics Data System (ADS)

Com intuito de despertar o interesse pelo estudo da astronomia, desenvolveu-se entre 2003 e 2006 no Centro Educacional do Serviço Social da Indústria situado no município de Mauá, São Paulo, um trabalho com duração de 12 meses para turmas de 11 e 12 anos, sendo três turmas por período (2003 / 2004, 2004 / 2005 e 2005 / 2006). O trabalho realizado, objetivando a introdução da astronomia básica com observações de constelações e das fases da Lua, permitindo estender-se a outros corpos celestes, iniciou-se com visita ao planetário Mundo Estelar, localizado no Ipiranga, São Paulo levantou-se a questão da importância do estudo da astronomia e foi lançado aos estudantes um trabalho de observação, com a proposta de localizar as constelações e compreender as fases da Lua, para o registro de tais observações, foram distribuídos mapas celestes, pastas, planilhas de anotações com lacunas para, constelações, fases da Lua e relatos, onde os estudantes acrescentaram pesquisas e relatórios. Os resultados dos 346 estudantes foram que 86,7% (300) concluíram a etapa de observação, destes 300 estudantes 43,3% (130) pesquisaram sobre as constelações e 19,0% (57) localizaram até quatro constelações. Dos 346 estudantes, 44,2% (153) registraram as fases da Lua equivocadamente e 10,4% (36) anexaram reportagens sobre astronomia. Conclui-se que os estudantes se dividiram em pesquisadores, sendo os estudantes que registraram e anexaram informações e, os observadores que preencheram as planilhas de observações, além de desenvolverem habilidades e competências relacionadas ao estudo da astronomia.

Gonzaga, E. P.; Voelzke, M. R.

2008-09-01

322

Molecular basis for H blood group deficiency in Bombay (Oh) and para-Bombay individuals.  

PubMed

The penultimate step in the biosynthesis of the human ABO blood group oligosaccharide antigens is catalyzed by alpha-(1,2)-fucosyltransferase(s) (GDP-L-fucose: beta-D-galactoside 2-alpha-L-fucosyltransferase, EC 2.4.1.69), whose expression is determined by the H and Secretor (SE) blood group loci (also known as FUT1 and FUT2, respectively). These enzymes construct Fuc alpha 1-->2Gal beta-linkages, known as H determinants, which are essential precursors to the A and B antigens. Erythrocytes from individuals with the rare Bombay and para-Bombay blood group phenotypes are deficient in H determinants, and thus A and B determinants, as a consequence of apparent homozygosity for null alleles at the H locus. We report a molecular analysis of a human alpha-(1,2)-fucosyltransferase gene, thought to correspond to the H blood group locus, in a Bombay pedigree and a para-Bombay pedigree. We find inactivating point mutations in the coding regions of both alleles of this gene in each H-deficient individual. These results define the molecular basis for H blood group antigen deficiency in Bombay and para-Bombay phenotypes, provide compelling evidence that this gene represents the human H blood group locus, and strongly support a hypothesis that the H and SE loci represent distinct alpha-(1,2)-fucosyltransferase genes. Candidate sequences for the human SE locus are identified by low-stringency Southern blot hybridization analyses, using a probe derived from the H alpha-(1,2)-fucosyltransferase gene. PMID:7912436

Kelly, R J; Ernst, L K; Larsen, R D; Bryant, J G; Robinson, J S; Lowe, J B

1994-06-21

323

Supported transition metal catalysts for para- to ortho-hydrogen conversion  

NASA Technical Reports Server (NTRS)

The main goal of this study was to develop and improve on existing catalysts for the conversion of ortho- to para-hydrogen. Starting with a commercially available Air Products nickel silicate, which had a beta value of 20, we were trying to synthesize catalysts that would be an improvement to AP. This was accomplished by preparing silicates with various metals as well as different preparation methods. We also prepared supported ruthenium catalysts by various techniques using several metal precursors to improve present technology. What was also found was that the activation conditions prior to catalytic testing was highly important for both the silicates and the supported ruthenium catalysts. While not the initial focus of the research, we made some interesting observations into the adsorption of H2 on ruthenium. This helped us to get a better understanding of how ortho- to para-H2 conversion takes place, and what features in a catalyst are important to optimize activity. Reactor design was the final area in which some interesting conclusions were drawn. As discussed earlier, the reactor catalyst bed must be constructed using straight 1/8 feet OD stainless steel tubing. It was determined that the use of 1/4 feet OD tubing caused two problems. First, the radius from the center of the bed to the wall was too great for thermal equilibrium. Since the reaction of ortho- to para-H2 is exothermic, the catalyst bed center was warmer than the edges. Second, the catalyst bed was too shallow using a 1/4 feet tube. This caused reactant blow-by which was thought to decrease the measured activity when the flow rate was increased. The 1/8 feet tube corrected both of these concerns.

Brooks, Christopher J.; Wang, Wei; Eyman, Darrell P.

1994-01-01

324

Structural and vibrational investigation of para-nitraminopyridine N-oxide  

Microsoft Academic Search

The X-ray and vibrational spectroscopic analysis of para-nitraminopyridine N-oxide are reported. The crystals of investigated compound belong to P21 of the monoclinic system, Z=4, a=3.735Å, b=11.767Å, c=14.679Å and ?=93.27°. Room temperature powder infrared and Raman spectra of the title compound and its deuterated analogue were measured.The molecular structure of p-nitraminopyridine N-oxide has been calculated with the aid of density functional

J. Oszust; J. Baran; A. Pietraszko; M. Drozd; Z. Talik

2005-01-01

325

Para-hexaphenyl nanofiber growth on Au-coated porous alumina templates  

NASA Astrophysics Data System (ADS)

The availability of easy and reproducible methods for formation of periodically nanostructured surfaces allows one to study the quasi-epitaxial growth of nanowires on such artificially modified substrates. Here, we demonstrate that crystalline nanofibers of para-hexaphenyl can grow on porous alumina templates with high pore regularity once the templates have been coated by a thin Au film. Nanofibers of that kind represent a model system for the general class of organic nanowires which have chemically changeable optoelectronic properties and hence are of interest for integration into future optoelectronic devices.

Madsen, M.; Kartopu, G.; Andersen, N. L.; Es-Souni, M.; Rubahn, H.-G.

2009-08-01

326

Path integral molecular dynamics simulation of solid para-hydrogen with an aluminum impurity  

NASA Astrophysics Data System (ADS)

The equilibrium properties of an aluminum impurity trapped in solid para-hydrogen have been studied. The results were compared to those of a previous study by Krumrine et al. [J. Chem. Phys. 113 (2000) 9079] with an atomic boron. In the presence of vacancy defect, when the orientation-dependent Al- pH 2 potential is used, the Al atom is displaced to a position half way between its original substituted site and the vacancy site. Thermodynamic results also indicate that the presence of a neighboring vacancy helps to stabilize the Al impurity to a far greater extent than in the case of the B impurity.

Mirijanian, Dina T.; Alexander, Millard H.; Voth, Gregory A.

2002-11-01

327

Photophysical and acid-base properties of para-substituted N,N-dimethylanilines  

NASA Astrophysics Data System (ADS)

Ultraviolet absorption and fluorescence spectra were collected for para-substituted N,N-dimethylanilines in aqueous solution at various pH conditions. Two fluorescing forms were observed for all studied compounds, one protonated (ANsH+) and the second unprotonated (ANs) each of them with specific spectroscopic properties. Changing pH of solution results in the displacement of the equilibrium between two forms. It was found that protonated aniline derivatives in aqueous solutions undergo very fast excited-state proton dissociation and the pKa values obtained from absorption and fluorescence spectra are similar. The excited state pKa? values were calculated using the Förster cycle method.

Szabelski, Mariusz; Bojarski, Piotr; Wieczorek, Zbigniew

2013-05-01

328

Photochemical transformation of nitrate in the presence of para-halogenated phenols in frozen solutions  

NASA Astrophysics Data System (ADS)

Photochemical reactions leading to the chemical transformation of trace compounds in the atmosphere do not only occur in the atmospheric gas and liquid phases, but also in the tropospheric ice phase. The photochemical reactions of trace compounds embedded in ice have important implications for the composition of the atmospheric boundary layer in ice and snow covered regions and for interpretation of concentration profiles in snow and ice in the context of the composition of the past atmosphere. One of the prominent reactions is the photolysis of nitrate. This reaction is well established in natural waters, and is of interest since formation of highly mutagenic/carcinogenic nitro-compounds is possible. In contrast, the photochemical behaviour of nitrate in ice and snow is more complex. The photolysis of nitrate embedded in ice has been shown to generate OH radical, NO2(g) and NO(g) as primary photoproducts, but little is known how this photochemistry is affected by the presence of organic impurities embedded in the ice surface. In this work, we studied the effect of the presence of para-halogenated phenols on the photo-transformation of frozen nitrate solutions by Diffuse Reflective Infrared Fourier Transform Spectroscopy (DRIFTS). Moreover, the evolution of volatile nitrogen oxides to the gas phase was monitored by a commercial chemiluminescence NO/NOy monitor, chemical ionization mass spectrometry (CIMS), and thermal-dissociation cavity ring-down spectroscopy (TD-CRDS). In addition, some of the organic intermediate products were characterized by GC/MS and HPLC/PDA. We show that DRIFTS can provide a qualitative picture of the chemical transformations that take place at the ice surface and kinetic data on the phototransformation of nitrate. The photochemistry of frozen solutions of nitrate in the presence of various para-halogenated phenols was found to be dependent on the ice temperature, pH, the light intensity, and the concentration and nature of para-halogenated phenols added. The release of NOy species to the gas-phase was dramatically accelerated by low pH values as well as the nature of para-halogen, in the order Cl>Br>F. The major species released were identified as NO2 and HONO.

Abida, O.; Osthoff, H. D.; Sutherland, T. C.

2010-12-01

329

Para[ 18 F]fluorobenzylguanidine kinetics in a canine coronary artery occlusion model  

Microsoft Academic Search

Background  The kinetics of para-[18F]fluorobenzylguanidine ([18F]PFBG) were investigated in a canine coronary artery occlusion model.\\u000a \\u000a \\u000a \\u000a Methods and Results  Five dogs were imaged by positron emission tomography (PET) before and after complete surgical ligation of the left anterior\\u000a descending coronary artery. PET studies included a 10-minute dynamic [13N]NH3 perfusion scan, followed 1 hour later by 3-hour dynamic [18F]PFBG scanning. [18F]PFBG and [13N]NH3 images

Clifford R. Berry; Pradeep K. Garg; Timothy R. DeGrado; Peter Hellyer; William Weber; Sudha Garg; Bernard Hansen; Michael R. Zalutsky; R. Edward Coleman

1996-01-01

330

Pressure-enhanced ortho-para conversion in solid hydrogen up to 58 GPa  

PubMed Central

We measured the ortho-para conversion rate in solid hydrogen by using Raman scattering in a diamond-anvil cell, extending previous measurements by a factor of 60 in pressure. We confirm previous experiments that suggested a decrease in the conversion rate above about 0.5 GPa. We observe a distinct minimum at 3 GPa followed by a drastic increase in the conversion rate to our maximum pressure of 58 GPa. This pressure enhancement of conversion is not predicted by previous theoretical treatments and must be due to a new conversion pathway.

Eggert, Jon H.; Karmon, Eran; Hemley, Russell J.; Mao, Ho-kwang; Goncharov, Alexander F.

1999-01-01

331

Analysis of Para Red and Sudan Dyes in Egg Yolk by UPLC–MS–MS  

Microsoft Academic Search

Matrix solid-phase dispersion (MSPD) with alumina N as adsorbent has been used for extraction of para red, Sudan 1, Sudan\\u000a 2, Sudan 3, and Sudan 4 dyes from egg yolk. The extracts were analyzed by ultra-performance liquid chromatography–tandem mass\\u000a spectrometry (UPLC–MS–MS). Mean recovery for the five dyes ranged from 63.2 to 98.6%, with CV 0.55–10.00%. One sample was\\u000a confirmed to

Xiaolin Hou; Yonggang Li; Shoujun Cao; Zhongwen Zhang; Yongnin Wu

2010-01-01

332

Metabolic influences for mutation induction curves after exposure to Sudan-1 and para red.  

PubMed

Sudan-1 and para red are industrial dyes that have been illegally added to some foodstuffs, leading to withdrawal of the adulterated products throughout the UK since 2003. This resulted in international concern that arose because Sudan-1 is classified by International Agency for Research on Cancer as a Category 3 carcinogen. However, little is known about the dose response of this chemical at low, more biologically relevant, doses. The study therefore aimed to characterize the dose response for gene mutation and chromosomal damage induced by two azo dyes, namely Sudan-1 and para red. Gene mutations were analysed using the hypoxanthine phosphoribosyltransferase forward mutation assay and chromosomal damage was measured using the cytokinesis-blocked micronucleus assay. Two cell lines were used in these investigations. These were the AHH-1 cell line, which inducibly expresses CYP1A1, and the MCL-5 cell line derived from a subpopulation of AHH-1 cells that expresses a particularly high level of CYP1A1 activity. The MCL-5 cell line has also been transfected with two plasmids that stably express CYP1A2, CYP2A6 and CYP3A4 and all four of these CYP enzymes are known to metabolically activate Sudan-1. AHH-1 cells were used to investigate the dose response of the azo dyes, and MCL-5 cells were used to see if the dose response changed with increased metabolism. Sudan-1 induced a non-linear dose-response curve for gene mutation and chromosomal damage in AHH-1 cells. The genotoxic activity of Sudan-1 was greatly increased in MCL-5 cells. This indicated that the oxidation metabolites from Sudan-1 were both more mutagenic and more clastogenic than the parent compound. Para red also demonstrated a non-linear dose response for both gene mutation and chromosome damage in AHH-1 cells, and an increase in micronuclei induction was observed after increased oxidative metabolism in MCL-5 cells. Sudan-1 and para red are genotoxic chemicals with non-linear dose responses in AHH-1 but not in MCL-5 cells, and oxidative metabolism increases the genotoxic effect of both compounds. PMID:20197315

Johnson, George E; Quick, Emma L; Parry, Elizabeth M; Parry, James M

2010-07-01

333

Salud Para Su Corazon (Health for Your Heart) Community Health Worker Model  

PubMed Central

This article describes 6 Salud Para Su Corazon (SPSC) family of programs that have addressed cardiovascular disease risk reduction in Hispanic communities facilitated by community health workers (CHWs) or Promotores de Salud (PS). A synopsis of the programs illustrates the designs and methodological approaches that combine community-based participatory research for 2 types of settings: community and clinical. Examples are provided as to how CHWs can serve as agents of change in these settings. A description is presented of a sustainability framework for the SPSC family of programs. Finally, implications are summarized for utilizing the SPSC CHW/PS model to inform ambulatory care management and policy.

Balcazar, H.; Alvarado, M.; Ortiz, G.

2012-01-01

334

Photoresponse of poly([ital para]-phenylenevinylene) light-emitting diodes  

SciTech Connect

We have studied the photoresponses of poly([ital para]-phenylene vinylene) (PPV) light-emitting diodes (LED's) with PPV derivatives sandwiched between tin oxide (ITO) and metals including calcium, aluminum, and copper. Under illumination all diodes exhibit relatively large photoconductive I(V) responses which cross the dark I(V) curve at a forward-bias voltage V[sub 0] that scales with the difference in work functions between the ITO and metal electrodes, the open-circuit voltage saturates at V[sub 0] and is temperature independent, and the enhanced electroluminescence intensity of the illuminated LED's correlates with the photocurrent. (AIP)

Wei, X.; Raikh, M.; Vardeny, Z.V. (Department of Physics, University of Utah, Salt Lake City, Utah 84112 (United States)); Yang, Y. (UNIAX Corporation, 5375 Overpass Road, Santa Barbara, California 93111 (United States)); Moses, D. (Institute of Polymers and Organic Solids, University of California, Santa Barbara, California 93106 (United States))

1994-06-15

335

Variability of kinetic parameters due to biomass acclimation: Case of para-nitrophenol biodegradation  

Microsoft Academic Search

The study regards para-nitrophenol (p-NP) removal by a mixed culture in a batch reactor under aerobic conditions performed at low ratio substrate (p-NP) to p-NP degrading microorganisms (0.09

Fériel Rezouga; Moktar Hamdi; Mathieu Sperandio

2009-01-01

336

A para-nitrophenol phosphonate probe labels distinct serine hydrolases of Arabidopsis.  

PubMed

Activity-based protein profiling represents a powerful methodology to probe the activity state of enzymes under various physiological conditions. Here we present the development of a para-nitrophenol phosphonate activity-based probe with structural similarities to the potent agrochemical paraoxon. We demonstrate that this probes labels distinct serine hydrolases with the carboxylesterase CXE12 as the predominant target in Arabidopsis thaliana. The designed probe features a distinct labeling pattern and therefore represents a promising chemical tool to investigate physiological roles of selected serine hydrolases such as CXE12 in plant biology. PMID:21763150

Nickel, Sabrina; Kaschani, Farnusch; Colby, Tom; van der Hoorn, Renier A L; Kaiser, Markus

2012-01-15

337

Near-resonance scattering of the para-H2 vibrons in (ortho-H2)x(para-H2)1-x mixed crystals  

NASA Astrophysics Data System (ADS)

The p-H2 vibrons hae been studied by high-resolution Raman scattering in mixed crystals of (o-H2)x(p-H2)1-x, (HD)x(p-H2)1-x, and (o-D2)0.069(p-H2)0.931. For increasing o-H2 concentration, the line shape broadens and becomes asymmetric with a tail towards higher frequencies. This effect is less pronounced in the HD- and the o-D2-doped crystals, where the energy difference between the p-H2 vibron and the stretching vibration of the impurity is much larger. Isolated impurities still have a symmetrical line shape, showing that the asymmetry is not due to inhomogeneities. Calculated line shapes by the coherent-potential-approximation technique are in very good qualitative agreement with the experimental results. The theory also accounts for previously published experimental data on the variations of the relative positions and intensities of the ortho and para peaks in (o-H2)x(p-H2)1-x.

de Kinder, J.; Bouwen, A.; Schoemaker, D.; Boukahil, A.; Huber, D. L.

1994-05-01

338

Molecularly imprinted polyaniline-polyvinyl sulphonic acid composite based sensor for para-nitrophenol detection.  

PubMed

We report results of the studies relating to the fabrication and characterization of a conducting polymer based molecularly imprinted para-nitrophenol (PNP) sensor. A water pollutant, para-nitrophenol is electrochemically imprinted with polyvinyl sulphonic acid (PVSA) doped polyaniline onto indium tin oxide (ITO) glass substrate. This PNP imprinted electrode (PNPI-PANI-PVSA/ITO) prepared via chronopotentiometric polymerization and over-oxidation is characterized by Fourier transform infra-red spectroscopy (FT-IR), UV-visible (UV-vis) spectroscopy, contact angle (CA), scanning electron microscopy (SEM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) studies. The response studies of PNPI-PANI-PVSA/ITO electrode carried out using DPV reveal a lower detection limit of 1×10(-3) mM, improved sensitivity as 1.5×10(-3) A mM(-1) and stability of 45 days. The PNPI-PANI-PVSA/ITO electrode shows good precision with relative standard deviation of 2.1% and good reproducibility with standard deviation of 3.78%. PMID:23622966

Roy, Abhijit Chandra; Nisha, V S; Dhand, Chetna; Ali, Md Azahar; Malhotra, B D

2013-05-13

339

Screening electronic communication through ortho-, meta- and para-substituted linkers separating subphthalocyanines and C60.  

PubMed

We have prepared two complementary series of SubPc-C(60) (SubPc=subphthalocyanine) electron/energy donor-acceptor systems, in which the two constituents are linked through ortho-, meta-, or para-substituted phenoxy spacers. In one of the series (1 a) the SubPc units bear iodine atoms, while in the other series (1 b) diphenylamino groups are linked to the SubPc macrocycles. The iodine atoms and diphenylamino groups both influence the resulting oxidation potentials of the electron-donating SubPc. They also modulate the outcome of excited state interactions, namely, energy and/or charge transfer. In addition, we have studied the impact that the substitution pattern in the phenoxy spacer exerts onto intramolecular processes in the ground and excited states. Although some of these processes are governed by the spatial separation between both components, the different electronic coupling through ortho-, meta-, or para- connections also plays decisive roles in some cases. PMID:18624288

González-Rodríguez, David; Torres, Tomás; Herranz, María Angeles; Echegoyen, Luis; Carbonell, Esther; Guldi, Dirk M

2008-01-01

340

Rotational relaxation of CS by collision with ortho- and para-H2 molecules.  

PubMed

Quantum mechanical investigation of the rotationally inelastic collisions of CS with ortho- and para-H2 molecules is reported. The new global four-dimensional potential energy surface presented in our recent work is used. Close coupling scattering calculations are performed in the rigid rotor approximation for ortho- and para-H2 colliding with CS in the j = 0-15 rotational levels and for collision energies ranging from 10(-2) to 10(3) cm(-1). The cross sections and rate coefficients for selected rotational transitions of CS are compared with the ones previously reported for the collision of CS with He. The largest discrepancies are observed at low collision energy, below 1 cm(-1). Above 10 cm(-1), the approximation using the square root of the relative mass of the colliders to calculate the cross sections between a molecule and H2 from the data available with (4)He is found to be a good qualitative approximation. The rate coefficients calculated with the electron gas model for the He-CS system show more discrepancy with our accurate results. However, scaling up these rates by a factor of 2 gives a qualitative agreement. PMID:24289351

Denis-Alpizar, Otoniel; Stoecklin, Thierry; Halvick, Philippe; Dubernet, Marie-Lise

2013-11-28

341

Crystal dimension of ZSM-5 influences on para selective disproportionation of ethylbenzene.  

PubMed

Crystal size and crystal dimensions are vital role in shape selective feature. Para selective disproportionation of EthylBenzene (Dip-EB) was investigated over ZSM-5 synthesized in acidic medium. The catalysts were prepared by hydrothermal process with various Si/Al ratios (50, 75 and 100) using fluoride ion precursor. This fluoride ion precursor dissolves the ZSM-5 nutrients below it neutral pH between 4 and 6. The synthesized material was subjected into various physico chemical characterizations such as XRD, SEM, TGA and BET analyses. The XRD patterns showed high crystalline nature and their resulting SEM images were also indicate thin prismatic crystals of large dimension compared with alkaline medium synthesized one. The BET results earned good textural property. Catalytic activity of vapor phase Dip-EB was carried out between 523 and 673 K. As their result, diethylbenzene (DEB) isomers were obtained, but para selective Diethylbenzene (p-DEB) was observed higher than others. The high selectivity towards p-DEB was due to large crystal dimension of ZSM-5 catalysts synthesized in fluoride medium. Hence it is good commercial application for petrochemical feed stock production. PMID:24745253

Hariharan, Srinivasan; Palanichamy, Muthaiahpillai

2014-03-01

342

Photoinduced reactions of para-quinones with bicyclopropylidene leading to diverse polycyclic compounds with spirocyclopropanes.  

PubMed

Photoinduced reactions of bicyclopropylidene (BCP) with para-quinones (p-quinones) including benzoquinones, naphthoquinones, and anthraquinones were found to proceed via different cycloaddition pathways and lead to diverse polycyclic products bearing spiropropyl moiety. Photocycloaddition of BCP with benzoquinones gave spirooxetanes as the primary products, which upon irradiation were able to rearrange into the spiro[4.5]deca-6,9-diene-2,8-diones as secondary photoproducts. Chemoselectivity of the photocycloaddition of BCP with naphthoquinones relies largely on the substitution groups linked to the C?C in between the two carbonyl groups to give different types of products. Photoreaction of BCP with 9,10-anthraquinone gave not only the spirooxetane product, but also a novel spiro[indan-1,1'-phthalan]-3'-one product whose formation might be initiated by a transannular attack of the C4 cyclopropyl radical to the para-carbonyl group. Mechanisms involved in the formation of diverse primary or secondary products in the photoreactions of BCP with p-quinones were proposed. Some of the photoreactions also hold potentials as useful synthetic protocols for important spiropolycyclic compounds such as sesquiterpenes. PMID:23692405

Wang, Wei; Zhang, Wen-Jie; Wang, Lei; Quah, Ching Kheng; Fun, Hoong-Kun; Xu, Jian-Hua; Zhang, Yan

2013-06-21

343

Rotational relaxation of CS by collision with ortho- and para-H{sub 2} molecules  

SciTech Connect

Quantum mechanical investigation of the rotationally inelastic collisions of CS with ortho- and para-H{sub 2} molecules is reported. The new global four-dimensional potential energy surface presented in our recent work is used. Close coupling scattering calculations are performed in the rigid rotor approximation for ortho- and para-H{sub 2} colliding with CS in the j = 0–15 rotational levels and for collision energies ranging from 10{sup ?2} to 10{sup 3} cm{sup ?1}. The cross sections and rate coefficients for selected rotational transitions of CS are compared with the ones previously reported for the collision of CS with He. The largest discrepancies are observed at low collision energy, below 1 cm{sup ?1}. Above 10 cm{sup ?1}, the approximation using the square root of the relative mass of the colliders to calculate the cross sections between a molecule and H{sub 2} from the data available with {sup 4}He is found to be a good qualitative approximation. The rate coefficients calculated with the electron gas model for the He-CS system show more discrepancy with our accurate results. However, scaling up these rates by a factor of 2 gives a qualitative agreement.

Denis-Alpizar, Otoniel [Université de Bordeaux, ISM, UMR CNRS 5255, 33405 Talence (France) [Université de Bordeaux, ISM, UMR CNRS 5255, 33405 Talence (France); Departamento de Física, Universidad de Matanzas, Matanzas 40100 (Cuba); Stoecklin, Thierry, E-mail: t.stoecklin@ism.u-bordeaux1.fr; Halvick, Philippe [Université de Bordeaux, ISM, UMR CNRS 5255, 33405 Talence (France)] [Université de Bordeaux, ISM, UMR CNRS 5255, 33405 Talence (France); Dubernet, Marie-Lise [Université Pierre et Marie Curie, LPMAA, UMR CNRS 7092, 75252 Paris, France and Observatoire de Paris, LUTH, UMR CNRS 8102, 92195 Meudon (France)] [Université Pierre et Marie Curie, LPMAA, UMR CNRS 7092, 75252 Paris, France and Observatoire de Paris, LUTH, UMR CNRS 8102, 92195 Meudon (France)

2013-11-28

344

Ortho-to-para ratio in interstellar water on the sightline toward Sagittarius B2(N).  

PubMed

The determination of the water ortho-to-para ratio (OPR) is of great interest for studies of the formation and thermal history of water ices in the interstellar medium and protoplanetary disk environments. We present new Herschel observations of the fundamental rotational transitions of ortho- and para-water on the sightline toward Sagittarius B2(N), which allow improved estimates of the measurement uncertainties due to instrumental effects and assumptions about the excitation of water molecules. These new measurements, suggesting a spin temperature of 24-32 K, confirm the earlier findings of an OPR below the high-temperature value on the nearby sightline toward Sagittarius B2(M). The exact implications of the low OPR in the galactic center molecular gas remain unclear and will greatly benefit from future laboratory measurements involving water freeze-out and evaporation processes under low-temperature conditions, similar to those present in the galactic interstellar medium. Given the specific conditions in the central region of the Milky Way, akin to those encountered in active Galactic nuclei, gas-phase processes under the influence of strong X-ray and cosmic ray ionization also have to be carefully considered. We summarize some of the latest laboratory measurements and their implications here. PMID:23656468

Lis, Dariusz C; Bergin, Edwin A; Schilke, Peter; van Dishoeck, Ewine F

2013-10-01

345

Ortho-to-Para Ratio in Interstellar Water on the Sightline toward Sagittarius B2(N)  

NASA Astrophysics Data System (ADS)

The determination of the water ortho-to-para ratio (OPR) is of great interest for studies of the formation and thermal history of water ices in the interstellar medium and protoplanetary disk environments. We present new Herschel observations of the fundamental rotational transitions of ortho- and para-water on the sightline toward Sagittarius B2(N), which allow improved estimates of the measurement uncertainties due to instrumental effects and assumptions about the excitation of water molecules. These new measurements, suggesting a spin temperature of 24-32 K, confirm the earlier findings of an OPR below the high-temperature value on the nearby sightline toward Sagittarius B2(M). The exact implications of the low OPR in the galactic center molecular gas remain unclear and will greatly benefit from future laboratory measurements involving water freeze-out and evaporation processes under low-temperature conditions, similar to those present in the galactic interstellar medium. Given the specific conditions in the central region of the Milky Way, akin to those encountered in active Galactic nuclei, gas-phase processes under the influence of strong X-ray and cosmic ray ionization also have to be carefully considered. We summarize some of the latest laboratory measurements and their implications here.

Lis, Dariusz C.; Bergin, Edwin A.; Schilke, Peter; van Dishoeck, Ewine F.

2013-10-01

346

The new ParaDIgm: IgM from bench to clinic  

PubMed Central

The inaugural IgM event entitled “The new ParaDIgm: IgM from bench to clinic” brought together the increasingly active and growing IgM antibody community to discuss recent advances and challenges facing the discovery and development of IgM antibody therapies and technologies. Researchers, clinicians and biomanufacturing experts delivered 21 talks on the basic science and isolation of IgM, upstream and downstream development, and formulation and clinical development of the molecules. Participants networked around topics aimed at exploring the full potential of IgM antibodies. The meeting was held at DECHEMA Gesellschaft für Chemische Technik und Biotechnologie e. V. (Society for Chemical Engineering and Biotechnology), a non-profit scientific and technical society based in Frankfurt am Main, Germany. The meeting was sponsored by Patrys, Laureate Biopharma, Bio-Rad Laboratories, BIA Separations, Percivia and the Bio Affinity Company (BAC). The second New ParaDIgm: IgM from bench to clinic meeting, will be held on April 23–24, 2013 in Frankfurt, Germany.

Hanala, Sherif

2012-01-01

347

Determination of the ortho to para ratio of H2Cl+ and H2O+ from submillimeter observations.  

PubMed

The opening of the submillimeter sky with the Herschel Space Observatory has led to the detection of new interstellar molecular ions, H2O(+), H2Cl(+), and HCl(+), which are important intermediates in the synthesis of water vapor and hydrogen chloride. In this paper, we report new observations of H2O(+) and H2Cl(+) performed with both Herschel and ground-based telescopes, to determine the abundances of their ortho and para forms separately and derive the ortho-to-para ratio. At the achieved signal-to-noise ratio, the observations are consistent with an ortho-to-para ratios of 3 for both H2O(+) and H2Cl(+), in all velocity components detected along the lines-of-sight to the massive star-forming regions W31C and W49N. We discuss the mechanisms that contribute to establishing the observed ortho-to-para ratio and point to the need for a better understanding of chemical reactions, which are important for establishing the H2O(+) and H2Cl(+) ortho-to-para ratios. PMID:23869910

Gerin, Maryvonne; de Luca, Massimo; Lis, Dariusz C; Kramer, Carsten; Navarro, Santiago; Neufeld, David; Indriolo, Nick; Godard, Benjamin; Le Petit, Franck; Peng, Ruisheng; Phillips, Thomas G; Roueff, Evelyne

2013-10-01

348

ORTHO-TO-PARA ABUNDANCE RATIO OF WATER ION IN COMET C/2001 Q4 (NEAT): IMPLICATION FOR ORTHO-TO-PARA ABUNDANCE RATIO OF WATER  

SciTech Connect

The ortho-to-para abundance ratio (OPR) of cometary molecules is considered to be one of the primordial characteristics of cometary ices, and contains information concerning their formation. Water is the most abundant species in cometary ices, and OPRs of water in comets have been determined from infrared spectroscopic observations of H{sub 2}O rovibrational transitions so far. In this paper, we present a new method to derive OPR of water in comets from the high-dispersion spectrum of the rovibronic emission of H{sub 2}O{sup +} in the optical wavelength region. The rovibronic emission lines of H{sub 2}O{sup +} are sometimes contaminated by other molecular emission lines but they are not affected seriously by telluric absorption compared with near-infrared observations. Since H{sub 2}O{sup +} ions are mainly produced from H{sub 2}O by photoionization in the coma, the OPR of H{sub 2}O{sup +} is considered to be equal to that of water based on the nuclear spin conservation through the reaction. We have developed a fluorescence excitation model of H{sub 2}O{sup +} and applied it to the spectrum of comet C/2001 Q4 (NEAT). The derived OPR of water is 2.54{sup +0.32}{sub -0.25}, which corresponds to a nuclear spin temperature (T{sub spin}) of 30{sup +10}{sub -4} K. This is consistent with the previous value determined in the near-infrared for the same comet (OPR = 2.6 {+-} 0.3, T{sub spin} = 31{sup +11}{sub -5} K).

Shinnaka, Yoshiharu; Kawakita, Hideyo; Kobayashi, Hitomi [Koyama Astronomical Observatory, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto 603-8555 (Japan); Boice, Daniel C.; Martinez, Susan E. [Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238 (United States)

2012-04-20

349

Compilação de dados atômicos e moleculares do UV ao IV próximo para uso em síntese espectral  

NASA Astrophysics Data System (ADS)

Espectros sintéticos são utéis em uma grande variedade de aplicações, desde análise de abundâncias em espectros estelares de alta resolução ao estudo de populações estelares em espectros integrados. A confiabilidade de um espectro sintético depende do modelo de atmosfera adotado, do código de formação de linhas e da qualidade dos dados atômicos e moleculares que são determinantes no cálculo das opacidades da fotosfera. O nosso grupo no departamento de Astronomia no IAG tem utilizado espectros sintéticos há mais de 15 anos, em aplicações voltadas principalmente para a análise de abundâncias de estrelas G, K e M e populações estelares velhas. Ao longo desse tempo, as listas de linhas vieram sendo construídas e atualizadas continuamente, e alguns acréscimos recentes podem ser citados: Castilho (1999, átomos e moléculas no UV), Schiavon (1998, bandas moleculares de TiO) e Melendez (2001, átomos e moléculas no IV próximo). Com o intuito de calcular uma grade de espectros do UV ao IV próximo para uso no estudo de populações estelares velhas, se fazia necessário compilar e homogeneizar as diversas listas em apenas uma lista atômica e uma molecular. Nesse processo, a nova lista compilada foi correlacionada com outras bases de dados (NIST, Kurucz Database, O' Brian et al. 1991) para atualização dos parâmetros que caracterizam a transição atômica (comprimento de onda, log gf e potencial de excitação). Adicionalmente as constantes de interação C6 foram calculadas segundo a teoria de Anstee & O'Mara (1995) e artigos posteriores. As bandas moleculares de CH e CN foram recalculadas com o programa LIFBASE (Luque & Crosley 1999). Nesse poster estão detalhados os procedimentos citados acima, as comparações entre espectros calculados com as novas listas e espectros observados em alta resolução do Sol e de Arcturus, e uma análise do impacto decorrente da utilização de diferentes modelos de atmosfera no espectro sintético. Ao final, temos uma lista de linhas atômicas com mais de 24.000 linhas e uma lista molecular com as moléculas CN, CH, OH, NH, MgH, C2, TiO Gama, CO, FeH, adequadas ao estudo de estrelas G, K e M e populações estelares velhas.

Coelho, P.; Barbuy, B.; Melendez, J.; Allen, D. M.; Castilho, B.

2003-08-01

350

Ricerche paleoclimatiche in ambiente lacustre: il contributo della task force Ambiente Globale e Cambiamenti Climatici. (Paleoclimatic investigations in lacustrine basins: Contribution of task force global environment and climatic change).  

National Technical Information Service (NTIS)

In the last ten years, paleoclimatic investigations on several crateric, volcano-tectonic, intermontane, and ephemeral lakes of central-southern Italy have been carried out by the researchers of the Global Environment and Climatic Changes Task Force of th...

C. Giraudi B. Narcisi

1994-01-01

351

Passivation of iron-based alloys in para-toluene sulfonic acid  

SciTech Connect

Potentiodynamic and surface analysis techniques were applied to investigate the passivation of metals in para-toluene sulfonic acids (PTSA). The diffusion-limiting current density was used to calculate the ferrous ion concentration which causes the precipitation of a pseudopassive film. From the surface analysis data, the Cr/Fe ratio in the passive film increases in order of 430, 304, and 316 stainless steels. To analyze the differences, a correction was made to the data so that the observed difference in the oxide film composition is not attributed simply to the Cr and Fe contents of the alloys. This method also was applied to correct the Ni/Fe ratio in the passive film. The authors conclude that the preferential dissolution of Ni and Fe leads to a Cr enrichment in the passive film.

Iuan Jou Yang; Mao Ying Teng (Materials Research Labs., Chutung, Hsinchu (Taiwan, Province of China))

1993-06-01

352

Quantum dynamical simulations for nuclear spin selective laser control of ortho- and para-fulvene  

NASA Astrophysics Data System (ADS)

In the present paper we explore the prospects for laser control of the photoinduced nonadiabatic dynamics of para- and ortho-fulvene with the help of quantum dynamical simulations. Previous investigations [Bearpark et al., J. Am. Chem. Soc. 118, 5253 (1996); Alfalah et al., J. Chem. Phys. 130, 124318 (2009)] show that photoisomerization of fulvene is hindered by ultrafast radiationless decay through a conical intersection at planar configuration. Here, we demonstrate that photoisomerization can nevertheless be initiated by damping unfavorable nuclear vibrations with properly designed laser pulses. Moreover, we show that the resulting intramolecular torsion is nuclear spin selective. The selectivity of the photoexcitation with respect to the nuclear spin isomers can be further enhanced by applying an optimized sequence of two laser pulses.

Belz, S.; Grohmann, T.; Leibscher, M.

2009-07-01

353

El Proyecto Sismico "LARSE" - Trabajando Hacia un Futuro con Mas Seguridad para Los Angeles  

USGS Publications Warehouse

La region de Los Angeles contiene una red de fallas activas, incluyendo muchas fallas por empuje que son profundas y no rompen la superficie de la tierra. Estas fallas ocultas incluyen la falla anteriormente desconocida que fue responsable por la devastacion que ocurrio durante el terremoto de Northridge en enero de 1994, el terremoto mas costoso en la historia de los Estados Unidos. El Experimento Sismico en la Region de Los Angeles (Los Angeles Region Seismic Experiment, LARSE), esta localizando los peligros ocultos de los terremotos debajo de la region de Los Angeles para mejorar la construccion de las estructuras que pueden apoyar terremotos que son inevitables en el futuro, y que ayudaran a los cientificos determinar donde occurira el sacudimento mas fuerte y poderoso.

Henyey, Thomas L.; Fuis, Gary S.; Benthien, Mark L.; Burdette, Thomas R.; Christofferson, Shari A.; Clayton, Robert W.; Criley, Edward E.; Davis, Paul M.; Hendley, James W., II; Kohler, Monica D.; Lutter, William J.; McRaney, John K.; Murphy, Janice M.; Okaya, David A.; Ryberg, Trond; Simila, Gerald W.; Stauffer, Peter H.

1999-01-01

354

Transient effects and pump depletion in stimulated Raman scattering. [Para-hydrogen  

SciTech Connect

Stimulated rotational Raman scattering in a 300-K multipass cell filled with para-H/sub 2/ with a single-mode CO/sub 2/-pumped laser is studied using a frequency-narrowed optical parametric oscillator (OPO) as a probe laser at the Stokes frequency for the S/sub 0/(O) transition. Amplification and pump depletion are examined as a function of incident pump energy. The pump depletion shows clear evidence of transient behavior. A theoretical treatment of transient stimulated Raman scattering, including effects of both pump depletion and medium saturation is presented. In a first approximation, diffraction effects are neglected, and only plane-wave interactions are considered. The theoretical results are compared to the experimental pulse shapes.

Carlsten, J.L.; Wenzel, R.G.; Druehl, K.

1983-01-01

355

Cholecystocutaneous fistula: an unusual complication of a para-umbilical hernia repair.  

PubMed

This case describes a 94-year-old woman who presented 2?years postsutured para-umbilical hernia repair with a painful black lump protruding through her scar with blood stained discharge. This was initially thought to be either ischaemic bowel secondary to strangulated incisional hernia or a large organised haematoma. An urgent CT scan was performed following which the patient passed two large calculi and bile-stained fluid spontaneously through the wound, making the diagnosis somewhat clearer. The scan revealed an incisional hernia containing the gallbladder and two large calculi at the skin surface and an incidental large caecal cancer with surrounding lymphadenopathy. Frail health and the incidental finding of a colon cancer rendered invasive surgical management inappropriate. Therefore, she was managed conservatively with antibiotics. A catheter was inserted into the fistula tract to allow free drainage and alleviate pressure-related symptoms. The patient was discharged following a multidisciplinary team discussion. PMID:24862413

Dixon, Steven; Sharma, Mitesh; Holtham, Stephen

2014-01-01

356

Puncture injection of para-toluenesulfonamide combined with chemoembolization for advanced hepatocellular carcinoma  

PubMed Central

Hepatocellular carcinoma (HCC) is difficult to eradicate due to its resilient nature. Portal vein is often involved in tumors of large size, which exclude the patient from surgical resection and local ablative therapy, such as percutaneous ethanol injection (PEI) and radiofrequency ablation (RFA) because they were considered neither effective nor safe. Currently, there is almost no effective treatment for HCC of such condition. As a unique antitumor agent in form of lipophilic fluid for local injection, para-toluenesulfonamide (PTS) produces mild side effects while necrotizing the tumor tissues quickly and efficiently. Being largely different from both PEI and RFA therapies, PTS can disseminate itself in tumors more easily than other caustic agents, such as alcohol. So PTS may offer additional benefit to HCCs with vascular involvement. We herein describe a 70-year-old HCC patient who was treated with the combination of PTS injection and transcatheter arterial chemoembolization, resulting in a significantly improved clinical prognosis.

He, Qing; Kuang, An-Ren; Guan, Yong-Song; Liu, Yue-Qing

2012-01-01

357

Searching for auxetics with DYNA3D and ParaDyn  

NASA Astrophysics Data System (ADS)

We sought to simulate auxetic behavior by carrying out dynamic analyses of mesoscopic model structures. We began by generating nearly periodic cellular structures. Four-node Shell elements and eight-node Brick elements are the basic building blocks for each cell. The shells and bricks obey standard elastic-plastic continuum mechanics. The dynamical response of the structures was next determined for a three-stage loading process: (1) homogeneous compression; (2) viscous relaxation; (3) uniaxial compression. The simulations were carried out with both serial and parallel computer codes - DYNA3D and ParaDyn - which describe the deformation of the shells and bricks with a robust contact algorithm. We summarize the results found here.

Hoover, Wm. G.; Hoover, C. G.

2005-03-01

358

Adsorption and organisation of para-hexaphenyl molecules on Si(100)  

NASA Astrophysics Data System (ADS)

Para-hexaphenyl molecules (p-6P: C36H26) can be grown as nanofibres on various surfaces having optical properties of technological relevance. We report here the first observations of the initial stages of adsorption of individual p-6P molecules on Si(100)-(2×1) using room temperature Scanning Tunnelling Microscopy (STM). Depending on the substrate temperature, the hexaphenyl molecules adsorb in two configurations; indicating both weak and strong chemisorption. All six phenyl rings are clearly visible and the molecules are found to adsorb with characteristic angles between the long axis of the molecule and the silicon dimer rows. A statistical analysis of the spatial distribution of the molecules suggests that the clustering required for crystallographic nanofibre growth does not occur at the atomic scale under the experimental conditions used here.

Cranney, M.; Chalopin, Y.; Mayne, A. J.; Dujardin, G.

2009-03-01

359

Food for Life / Comida para la Vida: creating a food festival to raise diabetes awareness.  

PubMed

African and Latino Americans have higher rates of diabetes and its complications than White Americans. Identifying people with undiagnosed diabetes and helping them obtain care can help to prevent complications and mortality. To kick off a screening initiative, our community-academic partnership created the "Food for Life Festival," or "Festival Comida para la Vida." This article will describe the community's perspective on the Festival, which was designed to screen residents, and demonstrate that eating healthy can be fun, tasty, and affordable in a community-centered, culturally consonant setting. More than 1,000 residents attended the event; 382 adults were screened for diabetes, and 181 scored as high risk. Fifteen restaurants distributed free samples of healthy versions of their popular dishes. Community residents, restaurateurs, and clinicians commented that the event transformed many of their preconceived ideas about healthy foods and patient care. PMID:20097997

Lancaster, Kristie; Walker, Willie; Vance, Thomas; Kaskel, Phyllis; Arniella, Guedy; Horowitz, Carol

2009-01-01

360

Pair potentials and equation of state of solid para-hydrogen to megabar pressure  

NASA Astrophysics Data System (ADS)

We compute by means of quantum Monte Carlo simulations the equation of state of bulk solid para-hydrogen extrapolated to zero temperature, up to a pressure of ˜2 Mbar. We compare the equation of state yielded by three different pair potentials, namely, the Silvera-Goldman (SG), Buck, and one recently proposed by Moraldi, modified at short distances to include a repulsive core, missing in the originally proposed potential. The Moraldi pair potential yields an equation of state in very good agreement with experiment at megabar pressures, owing to its softer core, and is at least as accurate as the SG or the Buck at saturated vapor pressure. Estimates for the experimentally measurable kinetic energy per molecule are provided for all pair potentials.

Omiyinka, Tokunbo; Boninsegni, Massimo

2013-07-01

361

Effect of alpha-methyl-para-tyrosine on response to cocaine challenge.  

PubMed

This study evaluated the effect of an acute reduction in catecholamine synthesis produced by alpha-methyl-para-tyrosine (AMPT), a tyrosine hydroxylase inhibitor, on cocaine-induced euphoria. In a blinded, placebo-controlled study, AMPT (1 g p.o. T.I.D.) was given to 10 non-treatment-seeking cocaine abusers prior to intranasal administration of 2 mg/kg cocaine. AMPT, but not placebo, reduced plasma levels of the dopamine metabolite homovanillic acid and the norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol. AMPT also elevated prolactin levels, indicating inhibition of the tuberoinfundibular dopamine system. AMPT pretreatment produced a trend toward diminished cocaine "high" AMPT also tended to lower heart rate and blood pressure responses to cocaine, but had no effect on serum cocaine levels. Although we cannot rule out the therapeutic potential of the depletion strategy, our results with AMPT alone, at this dose, do not strongly support it. PMID:9232210

Stine, S M; Krystal, J H; Petrakis, I L; Jatlow, P I; Heninger, G R; Kosten, T R; Charney, D S

1997-08-01

362

Ortho/para ratio of H2O+ toward Sagittarius B2(M) revisited.  

PubMed

The HIFI instrument aboard the Herschel satellite has allowed the observation and characterization of light hydrides, the building blocks of interstellar chemistry. In this article, we revisit the ortho/para ratio for H2O(+) toward the Sgr B2(M) cloud core. The line of sight toward this star forming region passes through several spiral arms and the gas in the Bar potential in the inner Galaxy. In contrast to earlier findings, which used fewer lines to constrain the ratio, we find a ratio of 3, which is uniformly consistent with high-temperature formation of the species. In view of the reactivity of this ion, this matches the expectations. PMID:23713712

Schilke, Peter; Lis, Dariusz C; Bergin, Edwin A; Higgins, Ronan; Comito, Claudia

2013-10-01

363

Surface treatment of para-aramid fiber by argon dielectric barrier discharge plasma at atmospheric pressure  

NASA Astrophysics Data System (ADS)

This paper is focused on influence of argon dielectric barrier discharge (DBD) plasma on the adhesive performance and wettability of para-aramid fibers and three parameters including treated power, exposure time and argon flux were detected. The interfacial shear strength (IFSS) was greatly increased by 28% with 300 W, 60 s, 2 L min-1 argon flux plasma treatment. The content of oxygen atom and oxygen-containing polar functional groups were enhanced after the argon plasma treated, so as the surface roughness, which contributed to the improvement of surface wettability and the decrease of contact angle with water. However, long-time exposure, exorbitant power or overlarge argon flux could partly destroy the prior effects of the treatment and damage the mechanical properties of fibers to some degree.

Gu, Ruxi; Yu, Junrong; Hu, Chengcheng; Chen, Lei; Zhu, Jing; Hu, Zuming

2012-10-01

364

Unusual Raman spectra of para-nitroaniline by sequential Fermi resonances.  

PubMed

In this communication, we report the unusual Raman spectra of para-nitroaniline (PNA) by sequential Fermi resonances. The combinational mode 1292 cm(-1) in the experimental Raman spectrum indirectly gains the initial spectral weight at 1392 cm(-1) by three sequential Fermi resonances. These Fermi resonances result in the strong interaction between the donor group of NH2 and the acceptor group of NO2. Our theoretical calculations provide reasonable interpretation for the abnormal Raman spectra of PNA. Experimental surface enhanced Raman scattering (SERS) spectrum of PNA further confirmed our conclusion, where the strongest Raman peak at 1292 cm(-1) is very weak, while the Raman peak at 1392 cm(-1) becoming the strongest Raman peak, which is consistent with the theoretical simulations. PMID:24370347

Xia, Jiarui; Zhu, Ling; Feng, Yanting; Li, Yongqing; Zhang, Zhenglong; Xia, Lixin; Liu, Liwei; Ma, Fengcai

2014-02-24

365

Poly(para-dioxanone)/inorganic particle composites as a novel biomaterial.  

PubMed

In this work, poly(para-dioxanone) (PPDO) was mixed with 1% (by weight) calcium carbonate (CaCO(3)), beta-tricalcium phosphate (beta-TCP), or calcium sulphate dihydrate (CSD) by solution co-precipitation. Samples were compression molded into bars using a platen-vulcanizing press. The morphology, thermal and mechanical properties, and crystalline structure of the composites were investigated using differential scanning calorimetry, polarized optical microscopy, scanning electron microscopy, and X-ray diffraction. All results suggest that three types of inorganic particle in this system promote the crystallinity of PPDO and act as an effective nucleating agent: the relative degree of crystallinity of PPDO increased from 30.74% to 100%, and the crystallization temperature of PPDO was increased by 18 degrees C. On the other hand, the mechanical properties of PPDO were changed by the presence of inorganic particles: the tensile strength of PPDO/CSD increased by 11.46%. PMID:19360890

Bai, Wei; Chen, Dongliang; Zhang, Zhiping; Li, Qing; Zhang, Dujuan; Xiong, Chengdong

2009-08-01

366

Rotational Spectroscopy of Carbon Monoxide Solvated with Para-Hydrogen Molecules  

NASA Astrophysics Data System (ADS)

Rotational spectra of carbon monoxide (^{12}C^{16}O and ^{13}C^{16}O) solvated with N=2 to 7 para-hydrogen (pH_2) molecules were studied by high resolution Fourier transform microwave spectroscopy. Infrared spectra of (pH_2)_N-CO clusters have previously been reported by Moroni et al. It is expected that the end-over-end rotational frequency decreases from N=2 to N=6, then increases with the addition of the next several helium atoms; this could indicate a significant decoupling of pH_2 density from CO rotation. By measuring the microwave transitions of these clusters we are able to separate the rotational and vibrational contributions to the rovibrational line positions. The trend of the pure rotational frequencies with increasing N-value will be presented. S. Moroni, M. Botti, S. De Palo, A. R. W. McKellar, J. Chem. Phys., 122, 094314 (2005).

Raston, Paul L.; Jäger, Wolfgang

2009-06-01

367

Determination of para red, Sudan dyes, canthaxanthin, and astaxanthin in animal feeds using UPLC.  

PubMed

A simple high-performance liquid chromatography method was developed for quantitative determination of para red, Sudan I, Sudan II, Sudan III, Sudan IV, canthaxanthin, and astaxanthin in feedstuff. The sample was extracted using acetonitrile and cleaned up on a C(18) SPE column. The residues were analyzed using ultra-performance liquid chromatography coupled to a diode array detector at 500 nm. The mobile phase was acetonitrile-formic acid-water with a gradient elution condition. The external standard curves were calibrated. The mean recoveries of the seven colorants were 62.7-91.0% with relative standard deviation 2.6-10.4% (intra-day) and 4.0-13.2% (inter-day). The detection limits were in the range of 0.006-0.02 mg/kg. PMID:20056031

Hou, Xiaolin; Li, Yonggang; Wu, Guojuan; Wang, Lei; Hong, Miao; Wu, Yongnin

2010-01-01

368

The Rayleigh-Taylor instability in quantum magnetized plasma with para- and ferromagnetic properties  

SciTech Connect

We investigate influence of magnetic field on the Rayleigh-Taylor instability in quantum plasmas with para- and ferromagnetic properties. Magnetization of quantum plasma happens due to the collective electron spin behavior at low temperature and high plasma density. In the classical case, without magnetization, magnetic field tends to stabilize plasma perturbations with wave numbers parallel to the field and with sufficiently short wavelengths. Paramagnetic effects in quantum plasma make this stabilization weaker. The stabilization disappears completely for short wavelength perturbations in the ferromagnetic limit, when the magnetic field is produced by intrinsic plasma magnetization only. Still, for perturbations of long and moderate wavelength, certain stabilization always takes place due to the nonlinear character of quantum plasma magnetization.

Modestov, Mikhail; Bychkov, Vitaly; Marklund, Mattias [Department of Physics, Umeaa University, 901 87 Umeaa (Sweden)

2009-03-15

369

The analysis of para-cresol production and tolerance in Clostridium difficile 027 and 012 strains  

PubMed Central

Background Clostridium difficile is the major cause of antibiotic associated diarrhoea and in recent years its increased prevalence has been linked to the emergence of hypervirulent clones such as the PCR-ribotype 027. Characteristically, C. difficile infection (CDI) occurs after treatment with broad-spectrum antibiotics, which disrupt the normal gut microflora and allow C. difficile to flourish. One of the relatively unique features of C. difficile is its ability to ferment tyrosine to para-cresol via the intermediate para-hydroxyphenylacetate (p-HPA). P-cresol is a phenolic compound with bacteriostatic properties which C. difficile can tolerate and may provide the organism with a competitive advantage over other gut microflora, enabling it to proliferate and cause CDI. It has been proposed that the hpdBCA operon, rarely found in other gut microflora, encodes the enzymes responsible for the conversion of p-HPA to p-cresol. Results We show that the PCR-ribotype 027 strain R20291 quantitatively produced more p-cresol in-vitro and was significantly more tolerant to p-cresol than the sequenced strain 630 (PCR-ribotype 012). Tyrosine conversion to p-HPA was only observed under certain conditions. We constructed gene inactivation mutants in the hpdBCA operon in strains R20291 and 630?erm which curtails their ability to produce p-cresol, confirming the role of these genes in p-cresol production. The mutants were equally able to tolerate p-cresol compared to the respective parent strains, suggesting that tolerance to p-cresol is not linked to its production. Conclusions C. difficile converts tyrosine to p-cresol, utilising the hpdBCA operon in C. difficile strains 630 and R20291. The hypervirulent strain R20291 exhibits increased production of and tolerance to p-cresol, which may be a contributory factor to the virulence of this strain and other hypervirulent PCR-ribotype 027 strains.

2011-01-01

370

Prevalence of oral trauma in Para-Pan American Games athletes.  

PubMed

The aim of this cross-sectional epidemiological survey was to assess the prevalence of oral trauma in athletes representing 25 countries competing at the most recent Para-Pan American Games (III PARAPAN) held in Rio de Janeiro, Brazil. The study was approved by the appropriate institutional review board. The examiners participated in standardization and calibration training sessions before the field phase began. Invitations were sent to >1200 participating athletes competing in eight sports and to the Medical Committee of the Para-Pan American Sports Organization before and during the III PARAPAN. A convenience sample of 120 athletes was recruited. After signing an informed consent, all athletes answered a questionnaire. Data were collected at the clinical examination and recorded in a specific trauma form. The mean age of the athletes was 32.5 years. Males comprised 79.2% of the sample; females 20.8%. The prevalence of oral trauma among the athletes was 47.5% (N = 57). However, only 15 athletes reported that these traumatic injuries were sports-related. The sport with the highest prevalence of oral trauma was judo (75%); the least was volleyball with no reported traumatic injuries. The most common traumatic injury was enamel fracture (27.4%). The teeth most affected were the maxillary permanent central incisors (N = 19), followed by the maxillary premolars (N = 8). On the basis of the results of this study of oral trauma among athletes examined at the III PARAPAN, a recommendation for enhanced educational efforts and the use of properly fitted mouthguards to prevent traumatic injuries among high-performance athletes with disabilities seems warranted. PMID:22882839

Andrade, Rafaela Amarante; Modesto, Adriana; Evans, Patricia Louise Scabell; Almeida, Anne Louise Scabell; da Silva, Juliana de Jesus Rodrigues; Guedes, Aurelino Machado Lima; Guedes, Fábio Ribeiro; Ranalli, Dennis N; Tinoco, Eduardo Muniz Barretto

2013-08-01

371

Salud para su Corazón: a community-based Latino cardiovascular disease prevention and outreach model.  

PubMed

Cardiovascular disease (CVD) is the leading cause of death for Latinos living in the United States. This population is generally unaware of important lifestyle or behavioral changes that can prevent CVD. The National Heart, Lung, and Blood Institute (NHLBI) designed and implemented Salud para su Corazón (Health for Your Heart), a culturally appropriate, community-based, theory-driven intervention model. NHLBI's goals were: (1) to design an intervention model appropriate to Latino populations; (2) to pilot test the model in a specific community with the objectives of increasing awareness about heart disease, raising knowledge about CVD prevention, and promoting heart-healthy lifestyles; and (3) to disseminate the model and the materials developed to other communities with similar needs. An agency-community partnership, under the leadership of the Community Alliance for Heart Health, guided all stages of the community intervention project. The multimedia bilingual community intervention included television telenovela format public service announcements (PSAs), radio programs, brochures, recipe booklets, charlas, a promotores training manual, and motivational videos. An evaluation survey assessed the impact of the intervention. A pre-post intervention survey was conducted with more than 300 participants, and results showed that the respondents were substantially more aware of risk factors for CVD, and had greatly increased their knowledge of ways to prevent heart disease. Dissemination efforts have resulted in numerous requests by health organizations, universities, and health maintenance organizations (HMOs) for educational materials and communication strategies produced by Salud para su Corazón. In addition, Univision, the largest Spanish-language broadcast television network, is airing the initiative's PSAs. Also, training seminars for promotores are being conducted in different regions of the United States, and several locations are planning to replicate this study. PMID:10555925

Alcalay, R; Alvarado, M; Balcazar, H; Newman, E; Huerta, E

1999-10-01

372

Self-assembled catalytic DNA nanostructures for synthesis of para-directed polyaniline.  

PubMed

Templated synthesis has been considered as an efficient approach to produce polyaniline (PANI) nanostructures. The features of DNA molecules enable a DNA template to be an intriguing template for fabrication of emeraldine PANI. In this work, we assembled HRP-mimicking DNAzyme with different artificial DNA nanostructures, aiming to manipulate the molecular structures and morphologies of PANI nanostructures through the controlled DNA self-assembly. UV-vis absorption spectra were used to investigate the molecular structures of PANI and monitor kinetic growth of PANI. It was found that PANI was well-doped at neutral pH and the redox behaviors of the resultant PANI were dependent on the charge density of the template, which was controlled by the template configurations. CD spectra indicated that the PANI threaded tightly around the helical DNA backbone, resulting in the right handedness of PANI. These reveal the formation of the emeraldine form of PANI that was doped by the DNA. The morphologies of the resultant PANI were studied by AFM and SEM. It was concluded from the imaging and spectroscopic kinetic results that PANI grew preferably from the DNAzyme sites and then expanded over the template to form 1D PANI nanostructures. The strategy of the DNAzyme-DNA template assembly brings several advantages in the synthesis of para-coupling PANI, including the region-selective growth of PANI, facilitating the formation of a para-coupling structure and facile regulation. We believe this study contributes significantly to the fabrication of doped PANI nanopatterns with controlled complexity, and the development of DNA nanotechnology. PMID:23272944

Wang, Zhen-Gang; Zhan, Pengfei; Ding, Baoquan

2013-02-26

373

Observation of Ortho-Para {bold H}{sup {bold +}}{sub {bold 3}} Selection Rules in Plasma Chemistry  

SciTech Connect

Intensity ratios of infrared spectral lines of ortho- and para-H{sup +}{sub 3} have been measured in hydrogen plasmas using normal and para-H{sub 2}. Large dependences of the intensity ratios on the parent gases have been observed, indicating the spin memory of protons even after chemical reactions. The results clearly demonstrate the existence of selection rules on nuclear spin modifications in chemical reactions theoretically anticipated by M. Quack[Mol.Phys.{bold 34}, 477 (1977)]. {copyright} {ital 1997} {ital The American Physical Society}

Uy, D.; Cordonnier, M.; Oka, T. [Department of Chemistry and Department of Astronomy and Astrophysics, The Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637 (United States)] [Department of Chemistry and Department of Astronomy and Astrophysics, The Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637 (United States)

1997-05-01

374

A kinetic method for para -nitrophenol determination based on its inhibitory effect on the catalatic reaction of catalase  

Microsoft Academic Search

The inhibitory effect of para-nitrophenol on the catalytic reaction of catalase was investigated. Michaelis-Menten kinetic parameters were determined from\\u000a Lineweaver-Burk plots obtained in the absence or in the presence of the inhibitor. The inhibitor pattern, revealed by the\\u000a Lineweaver-Burk plots, suggested a fully mixed inhibition mechanism. Spectrophotometric monitoring of the indicator reaction:\\u000a $$H_2 O_2 \\\\xrightarrow{{catalase,para - nitrophenol}}H_2 O + \\\\tfrac{1}{2}O_2

Claudia Mure?anu; Lucian Copolovici; Florina Pogùacean

2005-01-01

375

Chlorination of 2-phenoxypropanoic acid with NCP in aqueous acetic acid: using a novel ortho-para relationship and the para/meta ratio of substituent effects for mechanism elucidation.  

PubMed

Rate constants were measured for the oxidative chlorodehydrogenation of (R,S)-2-phenoxypropanoic acid and nine ortho-, ten para- and five meta-substituted derivatives using (R,S)-1-chloro-3-methyl-2,6-diphenylpiperidin-4-one (NCP) as chlorinating agent. The kinetics was run in 50% (v/v) aqueous acetic acid acidified with perchloric acid under pseudo-first-order conditions with respect to NCP at temperature intervals of 5 K between 298 and 318 K, except at the highest temperature for the meta derivatives. The dependence of rate constants on temperature was analyzed in terms of the isokinetic relationship (IKR). For the 20 reactions studied at five different temperatures, the isokinetic temperature was estimated to be 382 K, which suggests the preferential involvement of water molecules in the rate-determining step. The dependence of rate constants on meta and para substitution was analyzed using the tetralinear extension of the Hammett equation. The parameter lambda for the para/meta ratio of polar substituent effects was estimated to be 0.926, and its electrostatic modeling suggests the formation of an activated complex bearing an electric charge near the oxygen atom belonging to the phenoxy group. A new approach is introduced for examining the effect of ortho substituents on reaction rates. Using IKR-determined values of activation enthalpies for a set of nine pairs of substrates with a given substituent, a linear correlation is found between activation enthalpies of ortho and para derivatives. The correlation is interpreted in terms of the selectivity of the reactant toward para- or ortho-monosubstituted substrates, the slope of which being related to the ortho effect. This slope is thought to be approximated by the ratio of polar substituent effects from ortho and para positions in benzene derivatives. Using the electrostatic theory of through-space interactions and a dipole length of 0.153 nm, this ratio was calculated at various positions of a charged reaction center along the benzene C1-C4 axis, being about 2.5 near the ring and decreasing steeply with increasing distance until reaching a minimum value of -0.565 at 1.3 nm beyond the aromatic ring. Activation enthalpies and entropies were estimated for substrates bearing the isoselective substituent in either ortho and para positions, being demonstrated that they are much different from the values for the parent substrate. The electrophilic attack on the phenolic oxygen atom by the protonated chlorinating agent is proposed as the rate-determining step, this step being followed by the fast rearrangement of the intermediate thus formed, leading to products containing chlorine in the aromatic ring. PMID:17567074

Segurado, Manuel A P; Reis, João Carlos R; de Oliveira, Jaime D Gomes; Kabilan, Senthamaraikannan; Shanthi, Manohar

2007-07-01

376

Ortho- and para-selective ruthenium-catalyzed C(sp2)-H oxygenations of phenol derivatives.  

PubMed

Versatile ruthenium catalysts allowed for efficient direct oxygenations of aryl carbamates under remarkably mild reaction conditions. In addition to chelation-assisted C-H activation, the optimized ruthenium catalyst proved amenable to para-selective hydroxylations of anisoles without Lewis basic directing groups. PMID:23799802

Liu, Weiping; Ackermann, Lutz

2013-07-01

377

ParaMEME: a parallel implementation and a web interface for a DNA and protein motif discovery tool.  

PubMed

Many advanced software tools fail to reach a wide audience because they require specialized hardware, installation expertise, or an abundance of CPU cycles. The worldwide web offers a new opportunity for distributing such systems. One such program, MEME, discovers repeated patterns, called motifs, in sets of DNA or protein sequences. This tool is now available to biologists over the worldwide web, using an asynchronous, single-program multiple-data version of the program called ParaMEME that runs on an Intel Paragon XP/S parallel computer at the San Diego Super-computer Center. ParaMEME scales gracefully to 64 nodes on the Paragon with efficiencies > 72% for large data sets. The worldwide web interface to ParaMEME accepts a set of sequences interactively from a user, submits the sequences to the Paragon for analysis, and e-mails the results back to the user. ParaMEME is available for free public use at http://@www.sdsc.edu/CompSci/Biomed/ MEME. PMID:8902357

Grundy, W N; Bailey, T L; Elkan, C P

1996-08-01

378

Effect of Stress and Para-Chlorophenylalanine Upon Brain Serotonin, 5-Hydroxyindoleacetic Acid and Catecholamines in Grouped and Isolated Mice.  

National Technical Information Service (NTIS)

Para-chlorophenylalanine (pCpA), administered to mice only a few hours before they were sacrificed, lowered whole brain serotonin (5-HT) only slightly but caused a marked (27%) reduction in 5-hydroxyindoleacetic acid (5-HIAA). Restraint stress for 2.75 hr...

A. S. Welch B. L. Welch

1967-01-01

379

Acuerdos entre el gobierno central y los departamentos: una propuesta para aumentar la eficiencia del gasto público  

Microsoft Academic Search

El objetivo de este trabajo es proponer un instrumento para el seguimiento de la eficiencia del gasto público. El instrumento muestra que el gobierno central se puede apoyar en las administraciones departamentales con el fin de medir los productos del gasto. La idea central de la propuesta es que los objetivos de productividad acordados entre el nivel nacional y el

Isaac de León-Beltrán; Diego Jaramillo

2006-01-01

380

Una Metodología para Ajustar y Compensar las Diferencias de Riesgo entre el Sistema Público y Privado de Salud en Chile  

Microsoft Academic Search

En el marco conceptual de seguros de salud y ajuste de riesgo y a la luz de la experiencia internacional en Fondos de Compensación de Riesgos, este documento explora el problema del «descreme» que afecta al sistema de seguros Chileno. Se presenta una metodología para estimar diferencias de riesgo entre el sector público y privado de salud en Chile y

Verónica Vargas; Camilo Cid; Mauricio Matus; Iris Delgado; José Miguel Sánchez; Beatriz Heyermann; José Angulo

381

La valoraciòn econòmica de bienes y servicios ambientales como herramienta estrategica para la conservaciòn y uso sostenible de los ecosistemas  

Microsoft Academic Search

Resumen El trabajo corresponde a un estudio piloto hacia la implementación de una metodología que permita aproximar el valor monetario de los Bienes y Servicios Ambientales (BSA) ofertados por un ecosistema hídrico, caso “Ciénaga de la Caimanera, municipio de Coveñas, departamento de Sucre-Colombia”, como herramienta estratégica para incentivar la conservación y uso sostenible de los ecosistemas. Avanzar en procesos de

ADOLFO CARBAL HERRERA

2010-01-01

382

Custos de alimentação para caprinos na fase de aleitamento recebendo sucedâneos com fontes de proteína láctea e de origem vegetal  

Microsoft Academic Search

5 Bolsista de Pós-doutorado da Fapemig, UFV, Viçosa - MG. Resumo: Leite em pó integral de vaca, reconstituído, e sucedâneo comercial à base de mistura de proteínas vegetais isoladas foram comparados para avaliar custo de produção no aleitamento artificial em caprinos. Os animais foram separados das mães logo após o nascimento recebendo colostro tratado nas primeiras 6 horas de vida.

Ana Gabriela Pombo; Márcia Maria Cândido da Silva

383

Fontes de metionina em rações formuladas com base em aminoácidos totais ou digestíveis para frangas de reposição leves e semipesadas  

Microsoft Academic Search

RESUMO - Foram conduzidos dois experimentos com o objetivo de avaliar a utilização de duas fontes de metionina (em pó ou líquida) em rações formuladas com base em aminoácidos digestíveis ou totais para frangas de reposição leves e semipesadas, nas fases inicial (de 1 a 6 semanas de idade) e de crescimento (de 11 a 16 semanas de idade). Em

Luiz Gustavo Rombola; Douglas Emygdio de Faria; Bruno José Deponti; Flávio Henrique Araujo Silva; Daniel Emygdio de Faria Filho; Otto Mack Junqueira

2008-01-01

384

Four novel sequences in Drosophila melanogaster homologous to the auxiliary Para sodium channel subunit TipE.  

PubMed

TipE is an auxiliary subunit of the Drosophila Para sodium channel. Here we describe four sequences, TEH1-4, homologous to TipE in the Drosophila melanogaster genome, harboring all typical structures of both TipE and the beta-Subunit family of big-conductance Ca(2+)-activated potassium channels: short cytosolic N- and C-terminal stretches, two transmembrane domains, and a large extracellular loop with two disulfide bonds. Whereas TEH1 and TEH2 lack the TipE-specific extension in the extracellular loop, both TEH3 and TEH4 possess two extracellular EGF-like domains. A CNS-specific expression was found for TEH1, while TEH2-4 were more widely expressed. The genes for TEH2-4 are localized close to the tipE gene on chromosome 3L. Coexpression of TEH subunits with Para in Xenopus oocytes showed a strong (30-fold, TEH1), medium (5- to 10-fold, TEH2 and TEH3), or no (TEH4) increase in sodium current amplitude, while TipE increased the current 20-fold. In addition, steady-state inactivation and the recovery from fast inactivation were altered by coexpression of Para with TEH1. We conclude that members of the TEH-family are auxiliary subunits for Para sodium channels and possibly other ion channels. PMID:16325765

Derst, Christian; Walther, Christian; Veh, Rüdiger W; Wicher, Dieter; Heinemann, Stefan H

2006-01-20

385

Uncoupling of Nucleotide Hydrolysis and Polymerization in the ParA Protein Superfamily Disrupts DNA Segregation Dynamics*  

PubMed Central

DNA segregation in bacteria is mediated most frequently by proteins of the ParA superfamily that transport DNA molecules attached via the segrosome nucleoprotein complex. Segregation is governed by a cycle of ATP-induced polymerization and subsequent depolymerization of the ParA factor. Here, we establish that hyperactive ATPase variants of the ParA homolog ParF display altered segrosome dynamics that block accurate DNA segregation. An arginine finger-like motif in the ParG centromere-binding factor augments ParF ATPase activity but is ineffective in stimulating nucleotide hydrolysis by the hyperactive proteins. Moreover, whereas polymerization of wild-type ParF is accelerated by ATP and inhibited by ADP, filamentation of the mutated proteins is blocked indiscriminately by nucleotides. The mutations affect a triplet of conserved residues that are situated neither in canonical nucleotide binding and hydrolysis motifs in the ParF tertiary structure nor at interfaces implicated in ParF polymerization. Instead the residues are involved in shaping the contours of the binding pocket so that nucleotide binding locks the mutant proteins into a configuration that is refractory to polymerization. Thus, the architecture of the pocket not only is crucial for optimal ATPase kinetics but also plays a key role in the polymerization dynamics of ParA proteins that drive DNA segregation ubiquitously in procaryotes.

Dobruk-Serkowska, Aneta; Caccamo, Marisa; Rodriguez-Castaneda, Fernando; Wu, Meiyi; Bryce, Kerstyn; Ng, Irene; Schumacher, Maria A.; Barilla, Daniela; Hayes, Finbarr

2012-01-01

386

EL ANÁLISIS DE CITAS EN TRABAJOS DE INVESTIGADORES COMO MÉTODO PARA EL ESTUDIO DEL USO DE INFORMACIÓN EN BIBLIOTECAS  

Microsoft Academic Search

Resumen: Revisión bibliográfica sobre el análisis de citas como método para el estudio del uso y las necesidades de información por parte de los investigadores como usuarios de bibliotecas. Una vez comparados los estudios locales basados en las publicaciones de los usuarios potenciales de una biblioteca con los estudios de análisis de citas basados en la bibliografía circulante a nivel

Cristóbal Urbano Salido

2001-01-01

387

Theoretical Study of the Mechanism Behind the para-Selective Nitration of Toluene in Zeolite H-Beta  

SciTech Connect

Periodic density functional theory calculations were performed to investigate the origin of the favorable para-selective nitration of toluene exhibited by zeolite H-beta with acetyl nitrate nitration agent. Energy calculations were performed for each of the 32 crystallographically unique Bronsted acid sites of a beta polymorph B zeolite unit cell with multiple Bronsted acid sites of comparable stability. However, one particular aluminum T-site with three favorable Bronsted site oxygens embedded in a straight 12-T channel wall provides multiple favorable proton transfer sites. Transition state searches around this aluminum site were performed to determine the barrier to reaction for both para and ortho nitration of toluene. A three-step process was assumed for the nitration of toluene with two organic intermediates: the pi- and sigma-complexes. The rate limiting step is the proton transfer from the sigma-complex to a zeolite Bronsted site. The barrier for this step in ortho nitration is shown to be nearly 2.5 times that in para nitration. This discrepancy appears to be due to steric constraints imposed by the curvature of the large 12-T pore channels of beta and the toluene methyl group in the ortho approach that are not present in the para approach.

Andersen, Amity; Govind, Niranjan; Subramanian, Lalitha

2011-11-28

388

Evaluación del ciclo de vida aplicada en agrocadenas productivas: un instrumento de gestión ambiental para el diseño de políticas  

Microsoft Academic Search

La Evaluación del Ciclo de Vida del Producto (ECV) ha sido sugerida como un instrumento adecuado para ampliar el análisis y formulación de estrategias y políticas al utilizar el enfoque de Cadenas Globales de Mercancías. En este artículo se analizan los alcances de la aplicación de la ECV en diferentes sistemas de gestión ambiental lo cual permite establecer las áreas

Rafael Díaz Porras; Marjorie Hartley Ballestero

2006-01-01

389

Gestión para el desarrollo local sostenible en Granjas Agroindustriales y Empresas Azucareras del MINAZ de la provincia de Cienfuegos  

Microsoft Academic Search

La investigación se realizó en las entidades del MINAZ, teniendo como título: “Gestión para el desarrollo local sostenible en Granjas Agroindustriales y Empresas Azucareras del MINAZ en la provincia de Cienfuegos”. Tiene como objetivo general proponer un sistema de gestión ambiental integral que permita valorar e implantar las políticas de desarrollo local sostenible de las granjas agroindustriales y empresas azucareras

Eduardo Julio López Bastida; Mileisy Balbis Morejón

2008-01-01

390

Filtros hidráulicos PureForce TM diseñados para satisfacer o exceder los requisitos de alto rendimiento del equipo actual  

Microsoft Academic Search

El filtro hidráulico que antes no existía en los sistemas hidráulicos, ahora se ha transformado en un componente crítico. De hecho, son muy pocas las áreas de filtración que han cambiado con tanta rapidez como la hidráulica. La razón de un cambio tan rápido es que los sistemas hidráulicos están reemplazando a otros tipos de transmisiones. Para mejorar la seguridad

Medio Oriente; América del Sur

2009-01-01

391

APROXIMACION A LA ENSEÑANZA PARA PIANO A TRAVÉS DE LA CÁTEDRA DE PEDRO ALBÉNIZ EN EL REAL CONSERVATORIO DE MADRID  

Microsoft Academic Search

Pedro Albéniz como primer catedrático del Real Conservatorio de Madrid impulsó la consolidación del piano romántico durante la primera mitad del s. XIX, normalizando su enseñanza e introduciendo la escuela moderna del piano español, basada en el pianismo francés de la primera mitad del s. XIX. En su Método Completo para piano recogió las bases de su escuela pianística y

Gemma Salas

1999-01-01

392

A FALTA DE OPORTUNIDADES DE INSERÇÃO PARA OS CAIÇARAS E SEUS DESCENDENTES NA ATIVIDADE TURÍSTICA: O CASO DE ILHABELA  

Microsoft Academic Search

Introdução O turismo tem crescido em ritmo intenso em todo o Brasil. No litoral norte de São Paulo, em virtude, principalmente, da proximidade com a capital do estado - maior fluxo emissivo de turistas - esse crescimento é bastante acentuado. Ilhabela detém belezas naturais e cenários geográficos que estimulam os turistas e veranistas a escolherem esse destino para suas férias

Claudia Maria Astorino

393

Esquema de redundancia y distribución de carga de alta disponibilidad para la prestación de telefonía IP usando SIP  

Microsoft Academic Search

En este artículo se presenta un esquema de distribu ción de carga y redundancia en la infraestructura de un ISP (Intern et Service Provider) para la prestación de servicios de telefo nía IP (ITSPs) sobre Internet usando el protocolo SIP (Session Ini tiation Protocol) garantizando niveles de acceso al servici o similares a la PSTN (Public Switched Telephone Network) y

Andrés Parra Londoño; Fabio G. Guerrero

2009-01-01

394

Conservation of ParaHox genes' function in patterning of the digestive tract of the marine gastropod Gibbula varia  

PubMed Central

Background Presence of all three ParaHox genes has been described in deuterostomes and lophotrochozoans, but to date one of these three genes, Xlox has not been reported from any ecdysozoan taxa and both Xlox and Gsx are absent in nematodes. There is evidence that the ParaHox genes were ancestrally a single chromosomal cluster. Colinear expression of the ParaHox genes in anterior, middle, and posterior tissues of several species studied so far suggest that these genes may be responsible for axial patterning of the digestive tract. So far, there are no data on expression of these genes in molluscs. Results We isolated the complete coding sequences of the three Gibbula varia ParaHox genes, and then tested their expression in larval and postlarval development. In Gibbula varia, the ParaHox genes participate in patterning of the digestive tract and are expressed in some cells of the neuroectoderm. The expression of these genes coincides with the gradual formation of the gut in the larva. Gva-Gsx patterns potential neural precursors of cerebral ganglia as well as of the apical sensory organ. During larval development this gene is involved in the formation of the mouth and during postlarval development it is expressed in the precursor cells involved in secretion of the radula, the odontoblasts. Gva-Xolx and Gva-Cdx are involved in gut patterning in the middle and posterior parts of digestive tract, respectively. Both genes are expressed in some ventral neuroectodermal cells; however the expression of Gva-Cdx fades in later larval stages while the expression of Gva-Xolx in these cells persists. Conclusions In Gibbula varia the ParaHox genes are expressed during anterior-posterior patterning of the digestive system. This colinearity is not easy to spot during early larval stages because the differentiated endothelial cells within the yolk permanently migrate to their destinations in the gut. After torsion, Gsx patterns the mouth and foregut, Xlox the midgut gland or digestive gland, and Cdx the hindgut. ParaHox genes of Gibbula are also expressed during specification of cerebral and ventral neuroectodermal cells. Our results provide additional support for the ancestral complexity of Gsx expression and its ancestral role in mouth patterning in protostomes, which was secondarily lost or simplified in some species.

2010-01-01

395

A remarkably stable TipE gene cluster: evolution of insect Para sodium channel auxiliary subunits  

PubMed Central

Background First identified in fruit flies with temperature-sensitive paralysis phenotypes, the Drosophila melanogaster TipE locus encodes four voltage-gated sodium (NaV) channel auxiliary subunits. This cluster of TipE-like genes on chromosome 3L, and a fifth family member on chromosome 3R, are important for the optional expression and functionality of the Para NaV channel but appear quite distinct from auxiliary subunits in vertebrates. Here, we exploited available arthropod genomic resources to trace the origin of TipE-like genes by mapping their evolutionary histories and examining their genomic architectures. Results We identified a remarkably conserved synteny block of TipE-like orthologues with well-maintained local gene arrangements from 21 insect species. Homologues in the water flea, Daphnia pulex, suggest an ancestral pancrustacean repertoire of four TipE-like genes; a subsequent gene duplication may have generated functional redundancy allowing gene losses in the silk moth and mosquitoes. Intronic nesting of the insect TipE gene cluster probably occurred following the divergence from crustaceans, but in the flour beetle and silk moth genomes the clusters apparently escaped from nesting. Across Pancrustacea, TipE gene family members have experienced intronic nesting, escape from nesting, retrotransposition, translocation, and gene loss events while generally maintaining their local gene neighbourhoods. D. melanogaster TipE-like genes exhibit coordinated spatial and temporal regulation of expression distinct from their host gene but well-correlated with their regulatory target, the Para NaV channel, suggesting that functional constraints may preserve the TipE gene cluster. We identified homology between TipE-like NaV channel regulators and vertebrate Slo-beta auxiliary subunits of big-conductance calcium-activated potassium (BKCa) channels, which suggests that ion channel regulatory partners have evolved distinct lineage-specific characteristics. Conclusions TipE-like genes form a remarkably conserved genomic cluster across all examined insect genomes. This study reveals likely structural and functional constraints on the genomic evolution of insect TipE gene family members maintained in synteny over hundreds of millions of years of evolution. The likely common origin of these NaV channel regulators with BKCa auxiliary subunits highlights the evolutionary plasticity of ion channel regulatory mechanisms.

2011-01-01

396

Intensity-Modulated Radiation Therapy for the Treatment of Squamous Cell Anal Cancer With Para-aortic Nodal Involvement  

SciTech Connect

Purpose: To determine the rates of toxicity, locoregional control, distant control, and survival in anal cancer patients with para-aortic nodal involvement, treated with intensity-modulated radiotherapy (IMRT) and concurrent chemotherapy at a single institution. Methods and Materials: Between 2001 and 2007, 6 patients with squamous cell anal cancer and para-aortic nodal involvement were treated with IMRT and concurrent infusional 5-fluorouracil and cisplatin. The primary tumor was treated with a median dose of 57.5 Gy (range, 54-60 Gy), involved para-aortic, pelvic, and inguinal lymph nodes were treated with a median dose of 55 Gy (range, 50.5-55 Gy), and noninvolved nodal regions were treated with a median dose of 45 Gy (range, 43.5-45 Gy). Results: After a median follow-up of 25 months, none of the patients had a recurrence at the primary tumor, pelvic/inguinal nodes, or para-aortic nodes, whereas 2 patients developed distant metastases to the liver. Four of the 6 patients are alive. The 3-year actuarial locoregional control, distant control, and overall survival rates were 100%, 56%, and 63%, respectively. Four of the 6 patients developed Grade 3 acute gastrointestinal toxicity during chemoradiation. Conclusions: Intensity-modulated radiotherapy and concurrent chemotherapy could potentially serve as definitive therapy in anal cancer patients with para-aortic nodal involvement. Adjuvant chemotherapy may be indicated in these patients, as demonstrated by the distant failure rates. These patients need to be followed carefully because of the potential for treatment-related toxicities.

Hodges, Joseph C. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Das, Prajnan, E-mail: PrajDas@mdanderson.or [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Eng, Cathy [Department of Gastrointestinal Medical Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Reish, Andrew G. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Beddar, A. Sam [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Delclos, Marc E.; Krishnan, Sunil; Crane, Christopher H. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

2009-11-01

397

BUDDA (Bulge/Disk Decomposition Analysis) - um novo programa para análise estrutural de galáxias  

NASA Astrophysics Data System (ADS)

Tem sido prática comum nos últimos anos estudar a distribuição de luminosidade em galáxias fazendo uso da informação contida em toda a imagem da galáxia, já que esta técnica tem se mostrado muito mais confiável do que o simples ajuste de perfis radiais de luminosidade. Através destes estudos bidimensionais, melhores resultados tem sido obtidos na análise e.g. do Plano Fundamental, de correlações entre os parâmetros estruturais de galáxias, de sub-estruturas como barras e anéis nucleares etc. Apresentamos um novo código bidimensional, o BUDDA, de análise estrutural de galáxias, que será disponibilizado para a comunidade. Desenvolvido por nós, o código determina os parâmetros estruturais de galáxias de forma prática e robusta, e pode ser aplicado genericamente em qualquer estudo sobre a formação, evolução e estrutura de galáxias. O programa ainda permite a avaliação direta de sub-estruturas, através de imagens residuais que são obtidas ao se subtrair, das imagens originais, bojo e disco sintéticos que melhor representam essas componentes da galáxia sob consideração. Será apresentada a forma de utilização do código, bem como séries de testes que atestam a sua funcionalidade. Além disso, os resultados da aplicação do código em uma amostra de 51 galáxias serão expostos como exemplo prático, e do seu enorme potencial de uso.

Gadotti, D. A.; de Souza, R. E.; Dos Anjos, S.

2003-08-01

398

Why are para-hydrogen clusters superfluid? A quantum theorem of corresponding states study.  

PubMed

The quantum theorem of corresponding states is applied to N=13 and N=26 cold quantum fluid clusters to establish where para-hydrogen clusters lie in relation to more and less quantum delocalized systems. Path integral Monte Carlo calculations of the energies, densities, radial and pair distributions, and superfluid fractions are reported at T=0.5 K for a Lennard-Jones (LJ) (12,6) potential using six different de Boer parameters including the accepted value for hydrogen. The results indicate that the hydrogen clusters are on the borderline to being a nonsuperfluid solid but that the molecules are sufficiently delocalized to be superfluid. A general phase diagram for the total and kinetic energies of LJ (12,6) clusters encompassing all sizes from N=2 to N=infinity and for the entire range of de Boer parameters is presented. Finally the limiting de Boer parameters for quantum delocalization induced unbinding ("quantum unbinding") are estimated and the new results are found to agree with previous calculations for the bulk and smaller clusters. PMID:20707573

Sevryuk, Mikhail B; Toennies, J Peter; Ceperley, David M

2010-08-14

399

Cobalt-Schiff base complex catalyzed oxidation of para-substituted phenolics. Preparation of benzoquinones  

SciTech Connect

Para-substituted phenolics, serving as models for lignin (a renewable source of carbon), are oxidized to the corresponding benzoquinone with oxygen in the presence of catalytic amounts of Co-Schiff base complexes. The reaction products observed depend on the structure of the catalyst. The 5-coordinate catalysts (pyridine)[bis(salicylidene)ethylenediamine]cobalt[(pyr)Co(salen)]and[bis(salicylideneamino)ethylamine]cobalt [Co(n-Me salpr)] convert syringyl alcohol (3,5-dimethoxy-4-hydroxybenzyl alcohol) to 2,6-dimethoxybenzoquinone in high yield. In contrast, syringaldehyde (3,5-dimethoxy-4-hydroxybenzaldehyde) is unreactive toward these catalysts. However, the 4-coordinate Co(salen) converts syringaldehyde to 2,6-dimethoxybenzoiquinone in 72% isolated yield. Phenols bearing a single methoxy group on the ring are unreactive toward any catalyst in MeOH. However, vanillyl alcohol (3-methoxy-4-hydroxybenzyl alcohol) is converted to 2-methoxybenzo-quinone with Co(N-Me salpr) and oxygen in 43% yield in CH{sub 2}Cl{sub 2} and 58% yield in CH{sub 2}Cl{sub 2} in the presence of 1% CuCl{sub 2}. The success of the oxidations appears to be related to the ease of removal of the phenolic hydrogen by the Co/O{sub 2} complex. Competitive deactivation of the catalyst occurs with substrates of lower reactivity. 84 tabs.

Bozell, J.J.; Hames, B.R. [National Renewable Energy Lab., Golden, CO (United States); Dimmel, D.R. [Institute of Paper Science and Technology, Atlanta, GA (United States)

1995-04-21

400

Serotypes associated with the development of pneumococcal para-pneumonic effusion in adults.  

PubMed

Serotypes 1, 3, 7F and 19A are implicated in childhood pneumococcal para-pneumonic effusion (PPE). It is not known whether the same is true for adult PPE. A prospective cohort study was conducted over a 2-year period. Consecutive adults admitted with community-acquired pneumonia (CAP) were studied. Pneumococcal serotype was identified from urine samples using a multiplex immunoassay. Of 920 patients recruited, 366 had pneumococcal CAP; 100 of these had PPE and a serotype was determined in 73 patients. Factors associated with PPE were age, pneumonia severity index score and serotype. Serotypes most associated with PPE were 1 (18 (45%) out of 40), 19A (9 (45%) out of 20) and 3 (8 (40%) out of 20). Serotypes common in childhood PPE were independently associated with adult PPE (adjusted OR 2.3; p = 0.003). Serotypes not included in the 7-valent pneumococcal conjugate vaccine (PCV) were more likely to be associated with PPE (OR 2.1; p = 0.024) compared with those in the vaccine. Serotypes included in PCV-13 were as likely to be associated with PPE as those that are not (OR 0.8; p = 0.301). Serotypes 1, 3, 7F and 19A are independently associated with adult PPE, a similar finding to childhood PPE. Serotype replacement following pneumococcal vaccine implementation may influence the spectrum of clinical disease. PMID:23258784

Bewick, Thomas; Sheppard, Carmen; Greenwood, Sonia; Slack, Mary; Trotter, Caroline; George, Robert; Lim, Wei Shen

2013-09-01

401

Taxas de eventos para as fontes astrofísicas do detector Mario Schenberg  

NASA Astrophysics Data System (ADS)

O detector de ondas gravitacionais Mario Schenberg será sensível a sinais que cheguem à Terra com amplitude h~10-21 e dentro da faixa em frequências que varia de 3,0 a 3,4 kHz. As principais fontes astrofísicas em condições de gerar um sinal detectável pela antena Schenberg são: colapsos estelares que produzam eventos do tipo supernova; instabilidades hidrodinâmicas em estrelas de nêutrons; excitação dos modos fluído (modos f) de estrelas de nêutrons; excitação dos primeiros modos quadrupolares de buracos negros com massa ~ 3,8 M¤; coalescências de estrelas de nêutrons e buracos negros em sistemas binários e, ainda, espiralações de mini-buracos negros. Neste trabalho nós determinamos as taxas de eventos para o Schenberg associadas a dois tipos de fontes: através da de-excitação dos modos f de estrelas de nêutrons e através da coalescência de mini-buracos negros de 0,5 M¤ (que atualmente têm sido colocados como possíveis candidatos a objetos massivos do halo Galáctico). Nós mostramos que esses tipos de fontes poderão produzir sinais em ondas gravitacionais com uma taxa em torno de um evento por ano dentro da banda do Schenberg.

Castro, C. S.; Araujo, J. C. N.; Miranda, O. D.; Aguiar, O. D.

2003-08-01

402

Porous poly(para-phenylene) scaffolds for load-bearing orthopedic applications.  

PubMed

The focus of this study was to fabricate and investigate the mechanical behavior of porous poly(para-phenylene) (PPP) for potential use as a load-bearing orthopedic biomaterial. PPPs are known to have exceptional mechanical properties due to their aromatic backbone; however, the manufacturing and properties of PPP porous structures have not been previously investigated. Tailored porous structures with either small (150-250µm) or large (420-500µm) pore sizes were manufactured using a powder-sintering/salt-leaching technique. Porosities were systematically varied using 50 to 90vol%. Micro-computed tomography (µCT) and scanning electron microscopy (SEM) were used to verify an open-cell structure and investigate pore morphology of the scaffolds. Uniaxial mechanical behavior of solid and porous PPP samples was characterized through tensile and compressive testing. Both modulus and strength decreased with increasing porosity and matched well with foam theory. Porous scaffolds showed a significant decrease in strain-to-failure (<4%) under tensile loading and experienced linear elasticity, plastic deformation, and densification under compressive loading. Over the size ranges tested, pore size did not significantly influence the mechanical behavior of the scaffolds on a consistent basis. These results are discussed in regards to use of porous PPP for orthopedic applications and a prototype porous interbody fusion cage is presented. PMID:24374261

DiRienzo, Amy L; Yakacki, Christopher M; Frensemeier, Mareike; Schneider, Andreas S; Safranski, David L; Hoyt, Anthony J; Frick, Carl P

2014-02-01

403

Creation and evolution of net proton hyperpolarization arising from para-hydrogenation.  

PubMed

When a hydrogenation reaction is carried out with gaseous hydrogen enriched in its para- isomer in the earth magnetic field (prior to adiabatic insertion of the sample in the NMR magnet), enhanced proton longitudinal order (represented by 2I(z)(A)I(z)(B)) is created but also difference of enhanced polarizations (I(z)(A)-I(z)(B)). In a first part, it is shown theoretically and experimentally that the longitudinal relaxation time of this polarization difference is roughly twice the ones of individual polarizations. The second part is devoted to a pulse sequence designed for transforming this difference into net hyperpolarization. The evolution of this global hyperpolarization is studied experimentally in a third part and it is observed that a fraction of hyperpolarization possesses an effective longitudinal relaxation time similar to the one of the initial polarization difference. Those experimental results are interpreted by numerical calculations based on Solomon-type equations including the longitudinal order and possibly dipolar-csa cross correlation rates. PMID:21402486

Reineri, Francesca; Bouguet-Bonnet, Sabine; Canet, Daniel

2011-05-01

404

Tensile behavior of porous scaffolds made from poly(para phenylene) - biomed 2013.  

PubMed

The goal of this study was to fabricate and mechanically characterize a high-strength porous polymer scaffold for potential use as an orthopedic device. Poly(para-phenylene) (PPP) is an excellent candidate due to its exceptional strength and stiffness and relative inertness, but has never been explicitly investigated for use as a biomedical device. PPP has strength values 3 to 10 times higher and an elastic modulus nearly an order of magnitude higher than traditional polymers such as poly(methyl methacrylate) (PMMA), polycaprolactone (PCL), ultra-high molecular weight polyethylene (UHMWPE), and polyurethane (PU) and is significantly stronger and stiffer than polyetheretherketone (PEEK). By utilizing PPP we can overcome the mechanical limitations of traditional porous polymeric scaffolds since the outstanding stiffness of PPP allows for a highly porous structure appropriate for osteointegration that can match the stiffness of bone (100-250 MPa), while maintaining suitable mechanical properties for soft-tissue fixation. Porous samples were manufactured by powder sintering followed by particle leaching. The pore volume fraction was systematically varied from 50?80 vol% for a pore sizes from150-500 µm, as indicated by previous studies for optimal osteointegration. The tensile modulus of the porous samples was compared to the rule of mixtures, and closely matches foam theory up to 70 vol%. The experimental modulus for 70 vol% porous samples matches the stiffness of bone and contains pore sizes optimal for osteointegration. PMID:23686195

Dirienzo, Amy L; Yakacki, Christopher M; Safranski, David L; Frick, Carl P

2013-01-01

405

ParaText : scalable solutions for processing and searching very large document collections : final LDRD report.  

SciTech Connect

This report is a summary of the accomplishments of the 'Scalable Solutions for Processing and Searching Very Large Document Collections' LDRD, which ran from FY08 through FY10. Our goal was to investigate scalable text analysis; specifically, methods for information retrieval and visualization that could scale to extremely large document collections. Towards that end, we designed, implemented, and demonstrated a scalable framework for text analysis - ParaText - as a major project deliverable. Further, we demonstrated the benefits of using visual analysis in text analysis algorithm development, improved performance of heterogeneous ensemble models in data classification problems, and the advantages of information theoretic methods in user analysis and interpretation in cross language information retrieval. The project involved 5 members of the technical staff and 3 summer interns (including one who worked two summers). It resulted in a total of 14 publications, 3 new software libraries (2 open source and 1 internal to Sandia), several new end-user software applications, and over 20 presentations. Several follow-on projects have already begun or will start in FY11, with additional projects currently in proposal.

Crossno, Patricia Joyce; Dunlavy, Daniel M.; Stanton, Eric T.; Shead, Timothy M.

2010-09-01

406

Interface Properties of Organic para-Hexaphenyl/?-Sexithiophene Heterostructures Deposited on Highly Oriented Pyrolytic Graphite  

PubMed Central

It was recently reported, that heterostructures of para-hexaphenyl (p-6P) and ?-sexithiophene (6T) deposited on muscovite mica exhibit the intriguing possibility to prepare lasing nanofibers of tunable emission wavelength. For p-6P/6T heterostructures, two different types of 6T emission have been observed, namely, the well-known red emission of bulk 6T crystals and additionally a green emission connected to the interface between p-6P and 6T. In this study, the origin of the green fluorescence is investigated by photoelectron spectroscopy (PES). As a prerequisite, it is necessary to prepare structurally similar organic crystals on a conductive surface, which leads to the choice of highly oriented pyrolytic graphite (HOPG) as a substrate. The similarity between p-6P/6T heterostructures on muscovite mica and on HOPG is evidenced by X-ray diffraction (XRD), scanning force microscopy (SFM), and optical spectroscopy. PES measurements show that the interface between p-6P and 6T crystals is sharp on a molecular level without any sign of interface dipole formation or chemical interaction between the molecules. We therefore conclude that the different emission colors of the two 6T phases are caused by different types of molecular aggregation.

2013-01-01

407

Optimal timing algorithms of para-aortic counterpulsation device: an animal study.  

PubMed

Para-aortic counterpulsation device (PACD) is a promising therapy for severe heart failure (HF). However, the lack of knowledge about mechanisms has limited its clinical application. The aim of this study was to investigate the optimal timing algorithms. At the following four triggering algorithms, pre-R-wave-deflation and dicrotic notch-inflation (PD), pre-R-wave-deflation and postdicrotic notch-inflation (PP), R-wave-deflation and dicrotic notch-inflation (RD), and R-wave-deflation and postdicrotic notch-inflation (RP), hemodynamic effects of PACD were assessed in vivo. There was more significant promotion of left mean coronary artery flow (Q(LM)), carotid artery flow (Q(CA)), cardiac output (CO), pulmonary artery flow/LA pressure ratio (Q(PA)/LAP), left ventricular myocardial oxygen consumption (LVVO(2)), external LV work (ELVW), and cardiac mechanical efficiency (CME) at RD and RP models than PD and PP models. R-wave-deflation and postdicrotic notch-inflation model provided further benefits. There was significant correlation between LV functional parameters and carotid arterial reflux, but aortic pressure-related parameters. Filling at beginning of LV systolic phase and ejection at the end of isovolumic relaxation phase were the optimal triggering algorithms of PACD. It is suggested that carotid artery reflows and ventricular pressure-related parameters should be used as reference standard to adjust the timing of balloon inflation or deflation. PMID:22236623

Zhang, Guang-Wei; Wen, Ti; Gu, Tian-Xiang; Yu, Yang; Zhao, Ye; Zhang, Yu-Hai; Wang, Chun

2012-01-01

408

Electronic effects of para-substitution on the melting points of TAAILs.  

PubMed

Owing to numerous new applications, the interest in "task-specific" ionic liquids increased significantly over the last decade. But, unfortunately, the imidazolium-based ionic liquids (by far the most frequently used cations) have serious limitations when it comes to modifications of their properties. The new generation of ionic liquids, called tunable aryl-alkyl ionic liquids (TAAILs), replaces one of the two alkyl chains on the imidazolium ring with an aryl ring which allows a large degree of functionalization. Inductive, mesomeric, and steric effects as well as potentially also ?-? and ?-?(+) interactions provide a wide range of possibilities to tune this new class of ILs. We investigated the influence of electron-withdrawing and -donating substituents at the para-position of the aryl ring (NO(2), Cl, Br, EtO(CO), H, Me, OEt, OMe) by studying the changes in the melting points of the corresponding bromide and bis(trifluoromethanesulfonyl)imide, (N(Tf)(2)(-)), salts. In addition, we calculated (B3LYP/6-311++G(d,p)) the different charge distributions of substituted 1-aryl-3-propyl-imidazolium cations to understand the experimentally observed effects. The results indicated that the presence of electron-donating and -withdrawing groups leads to strong polarization effects in the cations. PMID:21254445

Schulz, Tobias; Ahrens, Sebastian; Meyer, Dirk; Allolio, Christoph; Peritz, Anke; Strassner, Thomas

2011-03-01

409

Polychlorinated Dibenzo-para-dioxins and Polychlorinated Dibenzofurans in Sediments from U.K. Estuaries  

NASA Astrophysics Data System (ADS)

Concentrations of polychlorinated dibenzo-para-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) have been determined in sediments from U.K. coastal locations adjacent to the estuaries of the Dee, Humber, Mersey, Tees, Tweed and Tyne and from an offshore site in Morecambe Bay. The sediments had total PCDD/DF concentrations of <100 pg g -1, except for the Dee and Morecambe Bay which had total PCDD (total PCDF) concentrations of 750 (390) and 207 pg g -1 (116 pg g -1), respectively. However, estuarine sediments collected during axial transects of Dee, Humber and Clyde Estuaries had total PCDD (total PCDF) concentrations in the range 530-1880 (340-710), 300-1890 (260-1240) and 290-4670 pg g -1 (100-1540 pg g -1), respectively. Examination of the homologue groups showed that about 70% of PCDDs were in the octa-chlorinated form in the Dee and Clyde, whereas for PCDFs the hepta- and hexa-chlorinated forms were relatively more important. The association of PCDD/DFs with particle surfaces was interpreted using data on sediment characteristics and a two-stage adsorption model. The conclusions from this study have implications for the estuarine transport of PCDD and PCDF and their uptake by benthic organisms.

Tyler, A. O.; Millward, G. E.; Jones, P. H.; Turner, A.

1994-07-01

410

Synthesis and spectral studies of platinum complexes of para-substituted 4-phenylthiosemicarbazides  

NASA Astrophysics Data System (ADS)

Platinum(II) complexes of para-substituted 4-phenylthiosemicarbazides, RPhNHCSNHNH 2 (R = H, CH 3, Br, F and NO 2) have been prepared and characterised by infrared and multinuclear NMR spectroscopy. The thiosemicarbazides act as bidentate ligands bonding through the sulphur and hydrazinic nitrogen atoms to form mixtures of cis- and trans-isomers of square planar complexes. 1H and 195Pt NMR spectroscopy suggest that the trans-isomer predominates in solution and that the relative ratio of trans: cis increases with increasing temperature of synthesis. 15N NMR spectroscopy has also been used to assign the cis- and trans-isomers of platinum complexes of 15N enriched 4-(4'-bromophenyl)thiosemicarbazide using 15N chemical shifts and … 1J 195Pt? 15N… values. The magnitude of the coupling constant … 1J 195Pt? 15N… of 238 Hz compares favourably with other platinum(II) complexes in which the 15N donor atom is trans to 15N and thus confirms the assignment of the trans-isomer as the predominant one in solution.

Arendse, Malcolm J.; Green, Ivan R.; Koch, K. R.

1997-09-01

411

Searching for auxetics with DYNA3D and ParaDyn  

NASA Astrophysics Data System (ADS)

The present special issue of physica status solidi (b), guest-edited by Krzysztof W. Wojciechowski, Andrew Alderson, Arkadiusz Braka, and Kim L. Alderson, is dedicated to Auxetics and Related Systems - materials which exhibit negative Poisson's ratio behaviour. Most papers were presented at a workshop which was held in Pozna-Bdlewo, 27-30 June 2004.In our Editor's Choice [1] novel simulations with a parallel finite element program, ParaDyn, have been conducted to study the formation of auxetic materials. Structures composed of either brick elements (hexahedra) or shell elements are constructed in a regular array of panels. These structures are compressed and relaxed to form an initial state for an auxetic (foam-like) material. The foam structure shown is composed of 208896 shell elements arranged in four by four panels. Applying a uniaxial compression to this structure characterizes the material behaviour of the lateral surfaces as normal (expanding) or auxetic (compressing).The first author, William G. Hoover, has been working in areas such as statistical and applied mechanics, nonlinear and molecular dynamics and is now pursuing, as he states on his own webpage, an active retired research career as Professor Emeritus of UC Davis.

Hoover, Wm. G.; Hoover, C. G.

2005-03-01

412

Analysis of passive motion of para- and retropharyngeal structures during swallowing using dynamic magnetic resonance imaging.  

PubMed

The purpose of this study was to analyze passive motion of the para- and retropharyngeal space (PRS) during swallowing using dynamic magnetic resonance imaging (MRI). We conducted a preliminary study involving 30 healthy volunteers who underwent dynamic MRI. Consecutive MRI axial images were obtained by examining the plane parallel to the hard palate at the level of the anterior inferior corner of C2. Anterior displacement of the posterior pharyngeal wall (PPW) was measured as a motion index of pharyngeal contraction. The displacement and internal angle of the bilateral external and internal carotid arteries (ECA and ICA) and the bilateral centroids of the PRS area, as well as the increase in PRS area, were calculated at rest and at maximum pharyngeal contraction. In most participants, the bilateral ECA, ICA, and centroids were anterointernally displaced by pharyngeal contraction. The normalized ECA displacement (r = 0.64, r (2) = 0.41), normalized ICA displacement (r = 0.60, r (2) = 0.37), and normalized centroid displacement (r = 0.43, r (2) = 0.19) were more than moderately positively correlated with the normalized PPW displacement. The normalized PRS area increase (r = 0.35, r (2) = 0.12) was weakly positively correlated with the normalized PPW displacement. These results revealed that PRS area increased as the ECA and ICA were drawn anterointernally via its passive motion by pharyngeal contraction. PMID:24859486

Chitose, Shun-Ichi; Haraguchi, Masahiro; Nagata, Shuji; Katayama, Reiji; Sato, Kiminori; Fukahori, Mioko; Sueyoshi, Shintaro; Kurita, Takashi; Abe, Toshi; Nakashima, Tadashi

2014-06-01

413

[Classification as carcinogenic for 2,3,7,8-tetrachlorodibenzo-para-dioxin: an eventful journey].  

PubMed

Carcinogenicity of 2,3,7,8-tetrachlorodibenzo-para-dioxin (2,3,7,8-TCDD) and some other dioxin congeners is long time discussed by epidemiological and experimental studies, often with conflicting findings. The inclusion of 2,3,7,8-TCDD in Group 1 by 1ARC in 1997 was based essentially on mechanistic evidence and experimental studies despite the limited evidence in humans. This procedure generated a lot of controversy. Some scientists agree with this classification and sometimes suggested increased cancer mortality risk with TCDD daily intake similar to those of the general population. Other authors re-analyzing data mainly from caselist previously investigated did not confirm the 2,3,7,8-TCDD carcinogenicity. In the review process of carcinogenic substances by IARC in 2010, the evidence for 2,3,7,8-TCDD carcinogenicity in humans upgraded from limited to sufficient, due to confirmed and integrated epidemiological evidences. It is also confirmed that these findings relate to all cancers combined, while for some "classic" cancers related to TCDD (as soft tissue sarcoma and non-Hodgkin lymphoma) the evidence remains limited. In this paper a literature review accompanied by comments is reported with the aim to provide information about the evaluation process and tools for its more critical and scrupulous interpretation. PMID:21425634

Apostoli, Pietro; Bergonzi, Roberto; Catalani, Simona

2011-01-01

414

Para-veterinary professionals and the development of quality, self-sustaining community-based services.  

PubMed

Livestock are a major asset for rural households throughout the developing world and are increasingly regarded as a means of reducing poverty. However, many rural areas are characterised by limited or no accessibility to veterinary services. Economic theory indicates that primary level services can be provided by para-veterinary professionals working as private operators and as an outreach component of veterinary clinics and pharmacies in small urban centres. Experience from the development of community-based animal health worker (CAHW) systems indicates that these workers can have a substantial impact on livestock morbidity and mortality through the treatment or prevention of a limited range of animal health problems. Factors for success include community involvement in the design and implementation of these systems, and involvement of the private sector to supply and supervise CAHWs. Examples of privatised and veterinary supervised CAHW networks are cited to show the considerable potential of this simple model to improve primary animal health services in marginalised areas. An analysis of constraints indicates that inappropriate policies and legislation are a major concern. By referring to the section on the evaluation of Veterinary Services in the OIE (World organisation for animal health) Terrestrial Animal Health Code, the paper proposes guidelines to assist governments in improving the regulation, quality, and co-ordination of privatised, veterinary supervised CAHW systems. PMID:15200100

Catley, A; Leyland, T; Mariner, J C; Akabwai, D M O; Admassu, B; Asfaw, W; Bekele, G; Hassan, H Sh

2004-04-01

415

LabVIEW-based control software for para-hydrogen induced polarization instrumentation.  

PubMed

The elucidation of cell metabolic mechanisms is the modern underpinning of the diagnosis, treatment, and in some cases the prevention of disease. Para-Hydrogen induced polarization (PHIP) enhances magnetic resonance imaging (MRI) signals over 10 000 fold, allowing for the MRI of cell metabolic mechanisms. This signal enhancement is the result of hyperpolarizing endogenous substances used as contrast agents during imaging. PHIP instrumentation hyperpolarizes Carbon-13 ((13)C) based substances using a process requiring control of a number of factors: chemical reaction timing, gas flow, monitoring of a static magnetic field (Bo), radio frequency (RF) irradiation timing, reaction temperature, and gas pressures. Current PHIP instruments manually control the hyperpolarization process resulting in the lack of the precise control of factors listed above, resulting in non-reproducible results. We discuss the design and implementation of a LabVIEW based computer program that automatically and precisely controls the delivery and manipulation of gases and samples, monitoring gas pressures, environmental temperature, and RF sample irradiation. We show that the automated control over the hyperpolarization process results in the hyperpolarization of hydroxyethylpropionate. The implementation of this software provides the fast prototyping of PHIP instrumentation for the evaluation of a myriad of (13)C based endogenous contrast agents used in molecular imaging. PMID:24784636

Agraz, Jose; Grunfeld, Alexander; Li, Debiao; Cunningham, Karl; Willey, Cindy; Pozos, Robert; Wagner, Shawn

2014-04-01

416

HERRAMIENTAS GERENCIALES PARA EL POSICIONAMIENTO DE LA EMPRESA SOSTENIBLE Y EL MARKETING ECOLÓGICO Management tools and positioning of sustainable enterprises and marketing ecological  

Microsoft Academic Search

RESUMEN La civilización humana está direccionando su acción comercial hacia el componente ecológico, tomando como principio la gerencia para proyectarse al mercado verde es decir, productos que generen menor impacto ambiental. La presente investigación tuvo como objetivo determinar las herramientas gerenciales para el posicionamiento de la empresa sostenible y el marketing ecológico. Este trabajo de investigación fue descriptivo, transeccional y

Dalia Plata de Plata

417

DISEÑO Y CONSTRUCCIÓN DE UN PROTOTIPO DIGITAL PARA DIAGNÓSTICAR FALLAS EN MOTORES DE INDUCCIÓN DESIGN AND CONSTRUCTION OF A DIGITAL PROTOTYPE TO DIAGNOSE FAULTS IN INDUCTION MOTORS  

Microsoft Academic Search

Recibido para revisar octubre 06 de 2006, aceptado febrero 05 de 2007, versión final febrero 28 de 2007 RESUMEN: En este trabajo se presenta el desarrollo de un prototipo digital utilizando un procesador de señales digitales DSP, al cual se le han incorporado dos algoritmos para diagnosticar fallas en el estator de motores de inducción. El primer algoritmo utiliza las

FERNANDO VILLADA DUQUE; Ingeniero Electricista; VELÁSQUEZ V; Ingeniero Electrónico; DIEGO R. CADAVID

2007-01-01

418

Involvement of the azorhizobial chromosome partition gene (parA) in the onset of bacteroid differentiation during Sesbania rostrata stem nodule development.  

PubMed

A parA gene in-frame deletion mutant of Azorhizobium caulinodans ORS571 (ORS571-?parA) was constructed to evaluate the roles of the chromosome-partitioning gene on various bacterial traits and on the development of stem-positioned nodules. The ?parA mutant showed a pleiomorphic cell shape phenotype and was polyploid, with differences in nucleoid sizes due to dramatic defects in chromosome partitioning. Upon inoculation of the ?parA mutant onto the stem of Sesbania rostrata, three types of immature nodule-like structures with impaired nitrogen-fixing activity were generated. Most showed signs of bacteroid early senescence. Moreover, the ?parA cells within the nodule-like structures exhibited multiple developmental-stage phenotypes. Since the bacA gene has been considered an indicator for bacteroid formation, we applied the expression pattern of bacA as a nodule maturity index in this study. Our data indicate that the bacA gene expression is parA dependent in symbiosis. The presence of the parA gene transcript was inversely correlated with the maturity of nodule; the transcript was switched off in fully mature bacteroids. In summary, our experimental evidence demonstrates that the parA gene not only plays crucial roles in cellular development when the microbe is free-living but also negatively regulates bacteroid formation in S. rostrata stem nodules. PMID:21571889

Liu, Chi-Te; Lee, Kyung-Bum; Wang, Yu-Sheng; Peng, Min-Hua; Lee, Kung-Ta; Suzuki, Shino; Suzuki, Tadahiro; Oyaizu, Hiroshi

2011-07-01

419

Normas Chilenas para el MACI: Una Integración de Criterios Categoriales y Dimensionales1 Chilean Norms for MACI: An Integration of Categorical and Dimensional Criteria  

Microsoft Academic Search

Resumen Este estudio desarrolló normas chilenas para el Inventario Clínico para Adolescentes de Millon (MACI) utilizando una muestra de baremación diferenciada por sexo y dicotomizada en dos grupos, no-consultantes (200 hombres y 206 mujeres) y consultantes (212 hombres y 189 mujeres), que respondió el MACI y el MMPI-A. Con los datos MACI se desarrolló un conjunto de análisis estadísticos de

Eugenia V. Vinet

2008-01-01

420

An apparatus to control and monitor the para-D 2 concentration in a solid deuterium, superthermal source of ultra-cold neutrons  

NASA Astrophysics Data System (ADS)

Controlling and measuring the concentration of para-D 2 is an essential step toward realizing solid deuterium as an intense ultra-cold neutron source. To this end, we implemented an experimental technique to convert para- to ortho-deuterium molecules by flowing D 2 gas through a cryogenic cell filled with paramagnetic hydrous ferric oxide granules. This process efficiently reduced the para-D 2 concentration from 33.3% to 1.5%. Rotational Raman spectroscopy was applied to measure the residual para-D 2 contamination to better than 2 parts in 10 3, and the hydrogen contamination to 1 part in 10 3. We also contrast our optical technique to conventional thermal conductivity measurements of the para-D 2 concentration, reporting some of the relevant strengths and weaknesses of our implementation of each technique.

Liu, C.-Y.; Lamoreaux, S. K.; Saunders, A.; Smith, D.; Young, A. R.

2003-08-01

421

River of Vitriol  

NSDL National Science Digital Library

This article offers a general overview of the microbiology of Spain's Rio Tinto. It introduces the history of the Rio Tinto, briefly describes some of the organisms that live there, and examines a few implications of the biological diversity for evolutionary studies. The article also explains that the acidic condition of the water may not be entirely due to mining activities, rather to the presence of specialized bacteria. It includes images of the Rio Tinto and diatoms.

Azria, Luis M.

2010-02-03

422

A 120-yr record of widespread contamination from mining of the Iberian pyrite belt  

Microsoft Academic Search

A metal-enriched seawater plume entering the western Mediterranean Sea through the Strait of Gibraltar originates 300 km to the west in the Rio Tinto estuary of southwestern Spain. Mining of Rio Tinto ore, one of the largest metal-rich sulfide deposits in the world, started well before Roman times. Contemporary Rio Tinto waters draining the region are highly acidic (pH 2.5)

A. van Geen; J. F. Adkins; E. A. Boyle; C. H. Nelson; A. Palanques

1997-01-01

423

Propuesta de un m‚todo para la elecci¢n de buenas alternativas para la localizaci¢n de empresas de reciclaje de RAEE en Espa¤a  

Microsoft Academic Search

Ante la necesidad de Espa¤a de instalar nuevas empresas de reciclaje de RAEE, este trabajo proporciona a los agentes decisores una ordenaci¢n de los principales municipios espa¤oles seg£n su apropiabilidad para la instalaci¢n de estas empresas. Desarrolla un procedimiento que consiste en la identificaci¢n de los factores relevantes que deben tenerse en cuenta y en la posterior aplicaci¢n de una

Dolores Queiruga; Javier Gonz lez Benito; Grit Walther; Thomas Spengler

2004-01-01

424

Characterization of a para -nitrophenol catabolic cluster in Pseudomonas sp. strain NyZ402 and construction of an engineered strain capable of simultaneously mineralizing both para - and ortho -nitrophenols  

Microsoft Academic Search

Pseudomonas sp. strain NyZ402 was isolated for its ability to grow on para-nitrophenol (PNP) as a sole source of carbon, nitrogen, and energy, and was shown to degrade PNP via an oxidization pathway.\\u000a This strain was also capable of growing on hydroquinone or catechol. A 15, 818 bp DNA fragment extending from a 800-bp DNA\\u000a fragment of hydroxyquinol 1,2-dioxygenase gene (pnpG)

Qing WeiHong; Hong Liu; Jun-Jie Zhang; Song-He Wang; Yi Xiao; Ning-Yi Zhou

2010-01-01

425

Liquid chromatographic determination of para-toluenesulfonamide in edible fillet tissues from three species of fish  

USGS Publications Warehouse

Chloramine-T (N-sodium-N-chloro-p-toluene-sulfonamide) is a candidate therapeutic drug for treating bacterial gill disease, a predominant disease of a variety of fish species. Research has been initiated to obtain the U.S. Food and Drug Administration's (FDA) approval for the use of chloramine-T on a variety of fish species. An attribute of a therapeutic aquaculture drug that must be characterized before the FDA approves its use is depletion of the drug's marker residue (the drug's parent compound or metabolite of highest concentration in an edible tissue). Para-Toluenesulfonamide (p-TSA) is the primary degradation product and marker residue for chloramine-T in rainbow trout. To conduct residue depletion studies for chloramine-T in fish, a robust analytical method sensitive and specific for p-TSA residues in edible fillet tissue from a variety of fish was required. Homogenized fillet tissues from rainbow trout (Oncorhynchus mykiss), walleye (Stizostedion vitreum), and channel catfish (Ictalurus punctatus) were fortified at nominal p-TSA concentrations of 17, 67, 200, 333, and 1000 ng/g. Samples were analyzed by isocratic reversed-phase liquid chromatography (LC) with absorbance detection at 226 nm. Mean recoveries of p-TSA ranged from 77 to 93.17%; relative standard deviations ranged from 1.5 to 14%; method quantitation limits ranged from 13 to 18 ng/g; and method detection limits ranged from 3.8 to 5.2 ng/g. The LC parameters produced p-TSA peaks without coelution of endogenous compounds and excluded chromatographic interference from at least 20 chemicals and drugs of potential use in aquaculture.

Meinertz, J. R.; Schmidt, L. J.; Stehly, G. R.; Gingerich, W. H.

1999-01-01

426

High-strength poly(para-phenylene) as an orthopedic biomaterial.  

PubMed

Poly(para-phenylene) (PPP) exhibits exceptional mechanical strength, stiffness, toughness, and chemical inertness, although it is not currently used in any biomedical applications. The purpose of this study is to serve as a preliminary investigation into the potential of PPP as a biomaterial in orthopedic load-bearing applications. Nuclear magnetic resonance (NMR) analysis confirmed a polymer structure composed of an aromatic backbone and side groups. Tensile PPP specimens along with samples from several other polymers often used for orthopedic applications were elongated to failure after being soaked in phosphate buffered saline (PBS) for 1 h, 1 day, 1 week, 2 weeks, 1 month, and more than 1 year. Results showed that PBS absorption of the PPP plateaued at 1 week at values of ?0.7 wt % and remained within one standard deviation when soaked for over 1 year. PBS absorption did not affect elastic modulus (5.0 GPa), yield strength (141 MPa), fracture strength (120 MPa) and strain-to-failure (17%) more than one standard deviation. Zero-to-tension fatigue testing established an endurance limit of approximately 35 MPa, which was relatively insensitive to frequency (1-10 Hz). Eagle's minimum essential medium (MEM) elution assay with fibroblasts confirmed that the PPP was noncytotoxic. Relative to other polymers used for load-bearing biomedical applications, PPP displays promising mechanical properties that remain stable in aqueous solution. Lastly, prototype PPP and polyetheretherketone (PEEK) bone plates were manufactured and tested, with the PPP plate showing a 38% higher maximum tensile load before failure. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3122-3129, 2014. PMID:24123879

Frick, Carl P; DiRienzo, Amy L; Hoyt, Anthony J; Safranski, David L; Saed, Mohand; Losty, Eric J; Yakacki, Christopher M

2014-09-01

427

Chelation Therapy of Manganese Intoxication with para-Aminosalicylic Acid (PAS) in Sprague-Dawley Rats  

PubMed Central

Para-aminosalicylic acid (PAS), an FDA-approved anti-tuberculosis drug, has been used successfully in the treatment of severe manganese (Mn)-induced Parkinsonism in humans (Jiang et al., JOEM 48:644, 2006). This study was conducted to explore the capability of PAS in reducing Mn concentrations in body fluids and tissues of Mn-exposed animals. Sprague-Dawley rats received daily intraperitoneally (i.p.) injections of 6 mg Mn/kg, 5 d/wk for 4 wks, followed by a daily subcutaneously (sc.) dose of PAS (100 and 200 mg/kg as the PAS-L and PAS-H group, respectively) for another 2, 3 or 6 wks. Mn exposure significantly increased the concentrations of Mn in plasma, red blood cells (RBC), cerebrospinal fluid (CSF), brain and soft tissues. Following PAS-H treatment for 3 wks, Mn levels in liver, heart, spleen and pancreas were significantly reduced by 25 to 33%, while 3 wks of PAS-L treatment did not show any effect. Further therapy with PAS-H for 6 wk reduced Mn levels in striatum, thalamus, choroid plexus, hippocampus and frontal cortex by 16 to 29% (p<0.05). Mn exposure greatly increased iron (Fe) and copper (Cu) concentrations in CSF, brain and liver. Treatment with PAS-H restored Fe and Cu levels comparable with control. These data suggest that PAS likely acts as a chelating agent to mobilize and remove tissue Mn. A high-dose and prolonged PAS treatment appears necessary for its therapeutic effectiveness.

Zheng, Wei; Jiang, Yue-Ming; Zhang, Yanshu; Jiang, Wendy; Wang, Xueqian; Cowan, Dallas M.

2008-01-01

428

Physical Activity and Sedentary Behaviors in Postpartum Latinas: Madres para la Salud  

PubMed Central

Purpose To describe the physical activity (PA) and sedentary behaviors of postpartum Latinas who are overweight or obese prior to initiating Madres para la Salud, a social-support mediated walking intervention to promote postpartum weight loss. Methods 139 postpartum (13.6 ± 7.7 weeks since childbirth) women (age = 28.3 ± 5.6 years and BMI = 29.7 ± 3.5 kg.m2), recruited from Phoenix area Latino-serving organizations completed the Stanford Brief Activity Survey (SBAS) and concurrently wore an accelerometer (AG) and a pedometer for 7-days, and kept a PA record (PAR). Results Most were classified as inactive and lightly active on the SBAS (51% inactive, 37% light, 11% moderate). Most time was spent in sedentary (512.0 ± 169.9 min.d?1) and light-intensity PA (242.4 ± 51.4 min.d?1) with less time in moderate-intensity lifestyle (78.3 ± 39.9 min.d?1), moderate-intensity walking (16.6 ± 14.4 min.d?1), and vigorous-intensity PA (0.34 ± 1.5 min.d?1). Pedometer steps.d?1 were low (total = 4,973 ± 2,202 steps; aerobic = 412 ± 774 steps) with most participants rated as sedentary (61%) or low-active (28.1%). Consistent with objective PA measures, PARs showed more time spent in light-intensity PAs such as home care, cooking, child- and self care tasks, occupation, religious events, and watching television. Conclusion By and large, the postpartum Latinas enrolled spent most of their day in low-intensity activity levels with little time spent in health-enhancing PA levels/behaviors. This demographic should be the focus of PA interventions to increase PA to health enhancing levels.

Ainsworth, Barbara E.; Keller, Colleen; Herrmann, Stephen; Belyea, Michael; Records, Kathryn; Nagle-Williams, Allison; Vega-Lopez, Sonia; Permana, Paska; Coonrod, Dean V.

2013-01-01

429

Nitration of endogenous para-hydroxyphenylacetic acid and the metabolism of nitrotyrosine.  

PubMed Central

Reactive nitrogen species, such as peroxynitrite, can nitrate tyrosine in proteins to form nitrotyrosine. Nitrotyrosine is metabolized to 3-nitro-4-hydroxyphenylacetic acid (NHPA), which is excreted in the urine. This has led to the notion that measurement of urinary NHPA may provide a time-integrated index of nitrotyrosine formation in vivo. However, it is not known whether NHPA is derived exclusively from metabolism of nitrotyrosine, or whether it can be formed by nitration of circulating para -hydroxyphenylacetic acid (PHPA), a metabolite of tyrosine. In the present study, we have developed a gas chromatography MS assay for NHPA and PHPA to determine whether or not NHPA can be formed directly by nitration of PHPA. Following the injection of nitrotyrosine, 0.5+/-0.16% of injected dose was recovered unchanged as nitrotyrosine, and 4.3+/-0.2% as NHPA in the urine. To determine whether or not NHPA could be formed by the nitration of PHPA, deuterium-labelled PHPA ([(2)H(6)]PHPA) was injected, and the formation of deuterated NHPA ([(2)H(5)]NHPA) was measured. Of the infused [(2)H(6)]PHPA, 78+/-2% was recovered in the urine unchanged, and approx. 0.23% was recovered as [(2)H(5)]NHPA. Since the plasma concentration of PHPA is markedly higher than free nitrotyrosine (approx. 400-fold), the nitration of high-circulating endogenous PHPA to form NHPA becomes very significant and accounts for the majority of NHPA excreted in urine. This is the first study to demonstrate that NHPA can be formed by nitration of PHPA in vivo, and that this is the major route for its formation.

Mani, Ali R; Pannala, Ananth S; Orie, Nelson N; Ollosson, Richard; Harry, David; Rice-Evans, Catherine A; Moore, Kevin P

2003-01-01

430

Genes, Enzymes, and Regulation of para-Cresol Metabolism in Geobacter metallireducens? †  

PubMed Central

In aerobic and facultatively anaerobic bacteria, the degradation of para-cresol (p-cresol) involves the initial hydroxylation to p-hydroxybenzyl alcohol by water catalyzed by the soluble, periplasmatic flavocytochrome p-cresol methylhydroxylase (PCMH; ?2?2 composition). In denitrifying bacteria the further metabolism proceeds via oxidation to p-hydroxybenzoate, the formation of p-hydroxybenzoyl-coenzyme A (CoA), and the subsequent dehydroxylation of the latter to benzoyl-CoA by reduction. In contrast, the strictly anaerobic Desulfobacterium cetonicum degrades p-cresol by addition to fumarate, yielding p-hydroxybenzylsuccinate. In this work, in vitro enzyme activity measurements revealed that the obligately anaerobic Geobacter metallireducens uses the p-cresol degradation pathway of denitrifying bacteria. Surprisingly, PCMH, which is supposed to catalyze both p-cresol hydroxylation and p-hydroxybenzyl alcohol oxidation to the corresponding aldehyde, was located in the membrane fraction. The ? subunit of the enzyme was present in two isoforms, suggesting an ????2 composition. We propose that the unusual asymmetric architecture and the membrane association of PCMH might be important for alternative electron transfer routes to either cytochrome c (in the case of p-cresol oxidation) or to menaquinone (in the case of p-hydroxybenzyl alcohol oxidation). Unusual properties of further enzymes of p-cresol metabolism, p-hydroxybenzoate-CoA ligase, and p-hydroxybenzoyl-CoA reductase were identified and are discussed. A proteomic approach identified a gene cluster comprising most of the putative structural genes for enzymes involved in p-cresol metabolism (pcm genes). Reverse transcription-PCR studies revealed a different regulation of transcription of pcm genes and the corresponding enzyme activities, suggesting the presence of posttranscriptional regulatory elements.

Peters, Franziska; Heintz, Dimitri; Johannes, Jorg; van Dorsselaer, Alain; Boll, Matthias

2007-01-01

431

Origin of the bimodal island size distribution in ultrathin films of para-hexaphenyl on mica  

NASA Astrophysics Data System (ADS)

Ultrathin films of para-hexaphenyl (6P) were prepared on freshly cleaved and sputter-amorphized mica(001) by physical vapor deposition. Ex situ atomic force microscopy (AFM) revealed a bimodal island size distribution for the films on both surfaces. On freshly cleaved mica long needlelike islands exist, which are surrounded by small crystallites. On the sputter-amorphized substrates, large dendritic islands exist which are again surrounded by small, compact islands. We could prove by thermal desorption spectroscopy that the small islands are the result of adsorbate-induced subsequent nucleation, when the films were exposed to air. In case of the freshly cleaved mica, islands grow on a wetting layer in vacuum. This layer dewets and forms the small islands upon venting, due to the adsorption of water. In the case of the amorphous mica substrate an equilibrium exists between the islands and a two-dimensional gas phase in the sub-monolayer regime. Again, the latter phase nucleates after venting. In a particular coverage range, islands due to nucleation during deposition and subsequent nucleation coexist on the substrate, leading to the bimodal island size distribution. Kinetic Monte Carlo (KMC) simulations were performed to model the nucleation process after venting on the sputter-modified mica substrate. The density of the subsequently nucleated islands just depends on the initial coverage and the critical island size. A critical cluster size of i = 7 molecules was determined for 6P on amorphized mica, by comparing the KMC results with the AFM images in case of adsorbate-induced nucleation. Furthermore, the experimentally obtained island size distributions could be well reproduced by KMC simulations.

Tumbek, L.; Gleichweit, C.; Zojer, K.; Winkler, A.

2012-08-01

432

Tyrosine-lipid peroxide adducts from radical termination: para coupling and intramolecular Diels-Alder cyclization.  

PubMed

Free radical co-oxidation of polyunsaturated lipids with tyrosine or phenolic analogues of tyrosine gave rise to lipid peroxide-tyrosine (phenol) adducts in both aqueous micellar and organic solutions. The novel adducts were isolated and characterized by 1D and 2D NMR spectroscopy as well as by mass spectrometry (MS). The spectral data suggest that the polyunsaturated lipid peroxyl radicals give stable peroxide coupling products exclusively at the para position of the tyrosyl (phenoxy) radicals. These adducts have characteristic (13)C chemical shifts at 185 ppm due to the cross-conjugated carbonyl of the phenol-derived cyclohexadienone. The primary peroxide adducts subsequently undergo intramolecular Diels-Alder (IMDA) cyclization, affording a number of diastereomeric tricyclic adducts that have characteristic carbonyl (13)C chemical shifts at ~198 ppm. All of the NMR HMBC and HSQC correlations support the structure assignments of the primary and Diels-Alder adducts, as does MS collision-induced dissociation data. Kinetic rate constants and activation parameters for the IMDA reaction were determined, and the primary adducts were reduced with cuprous ion to give a phenol-derived 4-hydroxycyclohexa-2,5-dienone. No products from adduction of peroxyls at the phenolic ortho position were found in either the primary or cuprous reduction product mixtures. These studies provide a framework for understanding the nature of lipid-protein adducts formed by peroxyl-tyrosyl radical-radical termination processes. Coupling of lipid peroxyl radicals with tyrosyl radicals leads to cyclohexenone and cyclohexadienone adducts, which are of interest in and of themselves since, as electrophiles, they are likely targets for protein nucleophiles. One consequence of lipid peroxyl reactions with tyrosyls may therefore be protein-protein cross-links via interprotein Michael adducts. PMID:21090613

Shchepin, Roman; Möller, Matias N; Kim, Hye-young H; Hatch, Duane M; Bartesaghi, Silvina; Kalyanaraman, Balaraman; Radi, Rafael; Porter, Ned A

2010-12-15

433

High stroke volume para-aortic counterpulsation device versus centrifugal pump in cardiogenic shock: experimental study.  

PubMed

During the last decades a number of left ventricular assist devices has been used especially for patients resistant to pharmacologic treatment and to intraaortic balloon pump (IABP) support for left ventricular failure. A high stroke volume para-aortic counterpulsation device (PACD) has been developed utilizing the principle of the diastolic counterpulsation technique. In this study the hemodynamic effects of the valveless PACD were compared to those of the centrifugal blood pump (CBP) in nine dogs in acute experimental cardiogenic shock. Hemodynamic measurements were obtained at baseline with both devices off, PACD on and CBP off, or PACD off and CBP on. There was no difference in mean aortic pressure between PACD on (60.0 +/- 11.5 mmHg) and CBP on (69.0 +/- 26.8 mmHg). Similarly, there was no difference in left ventricular end-diastolic pressure with the PACD on (11.9 +/- 5.4 mmHg) versus the CBP on (9.9 +/- 5.2 mmHg) or the cardiac index with the PACD on (84 +/- 36 ml/kg/min) versus the CBP on (77 +/- 36 ml/kg/min). However, the left ventricular systolic pressure (55.0 +/- 19.0 with PACD versus 73.0 +/- 26.0 with CBP,p < 0.001), the tension time index (712 +/- 381 versus 1333 +/- 694,p < 0.01), and the double product (5629 +/- 2574 versus 7440 +/- 3294,p < 0.01) were significantly lower during assistance with the PACD than with the CBP. It was concluded that PACD is at least as effective as CBP for restoring hemodynamic status during acute experimental cardiogenic shock. Moreover, the PACD unloads the left ventricle more effectively than CBP, making it suitable for left ventricular mechanical support in cases with reversible myocardial damage. PMID:9015178

Nanas, S N; Nanas, J N; Charitos, C E; Gougoulakis, A; Makaritsis, K; Chatzigeorgiou, J; Moussoutzani, K; Anastasiou-Nana, M I; Moulopoulos, S D

1997-01-01

434

Introduccion a la hidraulica de aguas subterraneas : un texto programado para auto-ensenanza  

USGS Publications Warehouse

Este ' texto programado esta diseflado para ayudarle a comprender la teoria de la hidniulica de aguas subterraneas por medio de la auto-enseflanza. La instrucci6n programada es un enfoque a una materia, un metodo de aprender;que no elimina el esfuerzo mental del proceso de aprendizaje. Algunas secciones de este programa necesitan solamente ser leidas; otras tendrian que ser elaboradas con lapiz y papel. Algunas preguntas pueden ser contestadas directamente; otras requieren calculos. A medida que se avanza en el texto, tendra que consultar frecuentemente textos o referencias sobre matematicas, mecanica de fluidos e hidrologia. En cada una de las ocho partes del texto, inicie el programa de instrucci6n leyendo la Secci6n 1. Elija una respuesta a la pregunta al final de la secci6n y dirijase a la nueva secci6n indicada al lado de la respuesta escogida. Si su respuesta fue correcta, pase a la secci6n que contiene materia nueva y otra pregunta, y proceda tal como en la Secci6n 1. Si su respuesta no fue correcta, dirijase a la secci6n que contiene explicaciones adicionales sobre el tema anterior y que le indica volver a la pregunta inicial e intentar de nuevo. En este caso, valdra Ia pena repasar el material de la secci6n anterior. Continue de esta man era en el programa hasta que llegue a Ia secci6n que indica el final de la parte. Observe que aunque las secciones estan en orden numerico en cada una de las ocho partes, por lo general, usted no procedeni en secuencia numerica (Secci6n 1 ala Secci6n 2, etc.) de principia a fin.

Bennett, Gordon D.

1987-01-01

435

Membrane Potential-Dependent Inhibition of the Na+,K+-ATPase by para-Nitrobenzyltriethylammonium Bromide  

PubMed Central

Membrane potential (VM)-dependent inhibitors of the Na+,K+-ATPase are a new class of compounds that may have inherent advantages over currently available drugs targeting this enzyme. However, two questions remain unanswered regarding these inhibitors: (1) what is the mechanism of VM-dependent Na+,K+-ATPase inhibition, and (2) is their binding affinity high enough to consider them as possible lead compounds? To address these questions, we investigated how a recently synthesized VM-dependent Na+,K+-ATPase inhibitor, para-nitrobenzyltriethylamine (pNBTEA), binds to the enzyme by measuring the extracellular pNBTEA concentration and VM dependence of ouabain-sensitive transient charge movements in whole-cell patch-clamped rat cardiac ventricular myocytes. By analyzing the kinetics of charge movements and the steady-state distribution of charge, we show that the VM-dependent properties of pNBTEA binding differ from those for extracellular Na+ and K+ binding, even though inhibitor binding is competitive with extracellular K+. The data were also fit to specific models for pNBTEA binding to show that pNBTEA binding is a rate-limiting VM-dependent reaction that, in light of homology models for the Na+,K+-ATPase, we interpret as a transfer reaction of pNBTEA from a peripheral binding site in the enzyme to a site near the known K+ coordination sites buried within the transmembrane helices of the enzyme. These models also suggest that binding occurs with an apparent affinity of 7 ?M. This apparent binding affinity suggests that high-affinity VM-dependent Na+,K+-ATPase inhibitors should be feasible to design and test as specific enzyme inhibitors.

Peluffo, R. Daniel

2012-01-01

436

On the mode-coupling treatment of collective density fluctuations for quantum liquids: para-hydrogen and normal liquid helium.  

PubMed

A novel quantum mode coupling theory combined with a kinetic approach is developed for the description of collective density fluctuations in quantum liquids characterized by Boltzmann statistics. Three mode-coupling approximations are presented and applied to study the dynamic response of para-hydrogen near the triple point and normal liquid helium above the ?-transition. The theory is compared with experimental results and to the exact imaginary time data generated by path integral Monte Carlo simulations. While for liquid para-hydrogen the combination of kinetic and quantum mode-coupling theory provides semi-quantitative results for both short and long time dynamics, it fails for normal liquid helium. A discussion of this failure based on the ideal gas limit is presented. PMID:21280769

Kletenik-Edelman, Orly; Reichman, David R; Rabani, Eran

2011-01-28

437

X-ray photoelectron spectroscopy study of para-substituted benzoic acids chemisorbed to aluminum oxide thin films  

SciTech Connect

A series of para-substituted, halogenated (F, Cl, Br, and I) benzoic acid monolayers were prepared on the native oxide of aluminum surfaces by solution self-assembly and spin-coating techniques. The monolayers were characterized by x-ray photoelectron spectroscopy (XPS) and water contact angles. Several general trends are apparent. First, the polarity of the solvent is critical to monolayer formation. Protic polar solvents produced low coverage monolayers; in contrast, nonpolar solvents produced higher coverage monolayers. Second, solution deposition yields a higher surface coverage than spin coating. Third, the thickness of the monolayers determined from XPS suggests the plane of the aromatic ring is perpendicular to the surface with the carboxylate functional group most likely binding in a bidentate chelating geometry. Fourth, the saturation coverage (?2.7 × 10{sup 14} molecules cm{sup ?2}) is independent of the para-substituent.

Kreil, Justin; Ellingsworth, Edward; Szulczewski, Greg [Department of Chemistry, The University of Alabama, Shelby Hall, 250 Hackberry Lane, Tuscaloosa, Alabama 35487 (United States)] [Department of Chemistry, The University of Alabama, Shelby Hall, 250 Hackberry Lane, Tuscaloosa, Alabama 35487 (United States)

2013-11-15

438

Electron-Donating Para-Methoxy Converts a Benzamide-Isoquinoline Derivative into a Highly Sigma-2 Receptor Selective Ligand  

PubMed Central

The sigma-2 (?2) receptor has been suggested to be a promising target for pharmacological interventions to curb tumor progression. Development of ?2-specific ligands, however, has been hindered by lack of understanding of molecular determinants that underlie selective ligand-?2 interactions. Here we have explored effects of electron donating and withdrawing groups on ligand selectivity for the ?2 versus ?1 receptor using new benzamide-isoquinoline derivatives. The electron-donating methoxy group increased but the electron-withdrawing nitro group decreased ?2 affinity. In particular, an extra methoxy added to the para-position (5e) of the benzamide phenyl ring of 5f dramatically improved (631 fold) the ?2 selectivity relative to the ?1 receptor. This para-position provided a sensitive site for effective manipulation of the sigma receptor subtype selectivity using either the methoxy or nitro substituent. Our study provides a useful guide for further improving the ?2-over-?1 selectivity of new ligands.

Hajipour, Abdol R.; Guo, Lian-Wang; Pal, Arindam; Mavlyutov, Timur; Ruoho, Arnold E.

2011-01-01

439

Trends in electron-ion dissociative recombination of benzene analogs with functional group substitutions: Negative Hammett ?para values  

NASA Astrophysics Data System (ADS)

An in-depth study of the effects of functional group substitution on benzene's electron-ion dissociative recombination (e-IDR) rate constant has been conducted. The e-IDR rate constants for benzene, biphenyl, toluene, ethylbenzene, anisole, phenol, and aniline have been measured using a Flowing Afterglow equipped with an electrostatic Langmuir probe (FALP). These measurements have been made over a series of temperatures from 300 to 550 K. A relationship between the Hammett ?para values for each compound and rate constant has indicated a trend in the e-IDR rate constants and possibly in their temperature dependence data. The Hammett ?para value is a method to describe the effect a functional group substituted to a benzene ring has upon the reaction rate constant.

Osborne, David; Lawson, Patrick Andrew; Adams, Nigel; Dotan, Itzhak

2014-06-01

440

Long-term survival after resection of pancreatic ductal adenocarcinoma with para-aortic lymph node metastasis: case report  

PubMed Central

Pancreatic cancer patients with para-aortic lymph node metastasis have a poor prognosis and patients living longer than 3 years are rare. We had a patient with pancreatic cancer who survived for more than 10 years after removal of the para-aortic lymph node metastasis. A 57-year-old woman was diagnosed with pancreatic head cancer and underwent a pancreaticoduodenectomy with subtotal gastric resection following Whipple reconstruction in 2000. Para-aortic lymph node metastasis was detected during the operation by intraoperative pathological diagnosis and an extended lymphadenectomy was performed with vascular skeletonization of the celiac and superior mesenteric arteries. In 2004, a low-density area was detected around the superior mesenteric artery (SMA) 5 cm from its root and she was treated with gemcitabine, and the area was undetectable after 3 years of treatment. In 2010, computed tomography showed a low-density area around the same lesion with an increased carcinoembryonic antigen level. After 4 months of gemcitabine treatment, we resected the tumor en bloc with the associated superior mesenteric vein and perineural tissue. Histopathological examination of the resected specimen revealed a well-differentiated tubular adenocarcinoma that closely resembled the original primary pancreatic cancer, indicating perineural recurrence 10 years after the initial resection. She had no recurrence around the SMA for more than one year. Although a meta-analysis has not proved the efficacy of preventive radical dissection, this case indicates that a patient with well-differentiated, chemotherapy-responsive pancreatic cancer with para-aortic lymph node metastasis could have a long survival time through extended dissection of the lymph nodes.

2013-01-01

441

Dysregulation in retinal para-inflammation and age-related retinal degeneration in CCL2 or CCR2 deficient mice.  

PubMed

We have shown previously that a para-inflammatory response exists at the retinal/choroidal interface in the aging eye; and this response plays an important role in maintaining retinal homeostasis under chronic stress conditions. We hypothesized that dysregulation of the para-inflammatory response may result in an overt pro-inflammatory response inducing retinal degeneration. In this study, we examined this hypothesis in mice deficient in chemokine CCL2 or its cognate receptor CCR2. CCL2- or CCR2-deficient mice developed retinal degenerative changes with age, characterized as retinal pigment epithelial (RPE) cell and photoreceptor cell death. Retinal cell death was associated with significantly more subretinal microglial accumulation and increased complement activation. In addition, monocytes from CCL2- or CCR2-deficient mice had reduced capacity for phagocytosis and chemotaxis, expressed less IL-10 but more iNOS, IL-12 and TNF-? when compared to monocytes from WT mice. Complement activation at the site of RPE cell death resulted in C3b/C3d but not C5b-9 deposition, indicating only partial activation of the complement pathway. Our results suggest that altered monocyte functions may convert the protective para-inflammatory response into an overtly harmful inflammation at the retina/choroidal interface in CCL2- or CCR2-deficient mice, leading to RPE and photoreceptor degeneration. These data support a concept whereby a protective para-inflammatory response relies upon a normally functioning innate immune system. If the innate immune system is deficient chronic stress may tip the balance towards an overt inflammatory response causing cell/tissue damage. PMID:21850237

Chen, Mei; Forrester, John V; Xu, Heping

2011-01-01

442

Increasing the Analytical Sensitivity by Oligonucleotides Modified with Para- and Ortho-Twisted Intercalating Nucleic Acids - TINA  

PubMed Central

The sensitivity and specificity of clinical diagnostic assays using DNA hybridization techniques are limited by the dissociation of double-stranded DNA (dsDNA) antiparallel duplex helices. This situation can be improved by addition of DNA stabilizing molecules such as nucleic acid intercalators. Here, we report the synthesis of a novel ortho-Twisted Intercalating Nucleic Acid (TINA) amidite utilizing the phosphoramidite approach, and examine the stabilizing effect of ortho- and para-TINA molecules in antiparallel DNA duplex formation. In a thermal stability assay, ortho- and para-TINA molecules increased the melting point (Tm) of Watson-Crick based antiparallel DNA duplexes. The increase in Tm was greatest when the intercalators were placed at the 5? and 3? termini (preferable) or, if placed internally, for each half or whole helix turn. Terminally positioned TINA molecules improved analytical sensitivity in a DNA hybridization capture assay targeting the Escherichia coli rrs gene. The corresponding sequence from the Pseudomonas aeruginosa rrs gene was used as cross-reactivity control. At 150 mM ionic strength, analytical sensitivity was improved 27-fold by addition of ortho-TINA molecules and 7-fold by addition of para-TINA molecules (versus the unmodified DNA oligonucleotide), with a 4-fold increase retained at 1 M ionic strength. Both intercalators sustained the discrimination of mismatches in the dsDNA (indicated by ?Tm), unless placed directly adjacent to the mismatch – in which case they partly concealed ?Tm (most pronounced for para-TINA molecules). We anticipate that the presented rules for placement of TINA molecules will be broadly applicable in hybridization capture assays and target amplification systems.

Schneider, Uffe V.; Geci, Imrich; J?hnk, Nina; Mikkelsen, Nikolaj D.; Pedersen, Erik B.; Lisby, Gorm

2011-01-01

443

Synthesis and characterization of novel photochromic side-chain liquid crystalline polymethacrylates containing para-nitroazobenzene group  

Microsoft Academic Search

Methacrylate monomers containing a mesogenic group and a photochromic para-nitroazobenzene group were prepared and polymerized in tetrahydrofuran (THF) using 2,2?-azobis(isobutyronitrile) (AIBN) as initiator at 67°C. The polymers were characterized by 1H NMR, IR, UV-Vis spectra and elemental analyses. The molecular weights Mw and Mn of the polymers were determined by gel permeation chromatography (GPC). The thermal properties of the polymers

Hui-Qi Zhang; Wen-Qiang Huang; chen-xi li; Bing-Lin He

1998-01-01

444

Cloning and functional analysis of tipE, a novel membrane protein that enhances drosophila para sodium channel function  

Microsoft Academic Search

Voltage-dependent sodium channels are involved in the initiation and propagation of action potentials in many excitable cells. Here we report that tipE, a gene defined by a temperature-sensitive paralytic mutation in Drosophila, encodes a novel integral membrane protein that dramatically stimulates functional expression in Xenopus oocytes of the Drosophila sodium channel ? subunit encoded by the paralytic (para) locus. Using

Guoping Feng; Péter Deak; Maninder Chopra; Linda M Hall

1995-01-01

445

Four novel sequences in Drosophila melanogaster homologous to the auxiliary Para sodium channel subunit TipE  

Microsoft Academic Search

TipE is an auxiliary subunit of the Drosophila Para sodium channel. Here we describe four sequences, TEH1-4, homologous to TipE in the Drosophila melanogaster genome, harboring all typical structures of both TipE and the ?-Subunit family of big-conductance Ca2+-activated potassium channels: short cytosolic N- and C-terminal stretches, two transmembrane domains, and a large extracellular loop with two disulfide bonds. Whereas

Christian Derst; Christian Walther; Rüdiger W. Veh; Dieter Wicher; Stefan H. Heinemann

2006-01-01

446

Se da a conocer el plan del Instituto Nacional del Cáncer para acelerar la investigación del cáncer  

Cancer.gov

En la 100va Reunión Anual de la Asociación Estadounidense de Investigación del Cáncer realizada en Denver, el director del Instituto Nacional del Cáncer, doctor John E. Niederhuber, dio a conocer detalles importantes, tales como financiamiento de más subvenciones, creación de una plataforma para atención personalizada del cáncer y un programa acelerado de genética del cáncer que hará avanzar la investigación oncológica en este nuevo ambiente económico.

447

Characterization and mutagenesis of a two-component monooxygenase involved in para-nitrophenol degradation by an Arthrobacter strain  

Microsoft Academic Search

para-Nitrophenol (PNP) degradation cluster was cloned from a newly isolated Arthrobacter sp. strain NyZ415 by genome walking extending from a conserved region of gene encoding the oxygenase component of PNP monooxygenase. Sequence analysis indicated it contained 12 open reading frames including genes npdA1 and npdA2 which encoded the reductase and oxygenase components of PNP monooxygenase, respectively. Both NpdA1 and NpdA2

Ping-Ping Liu; Jun-Jie Zhang; Ning-Yi Zhou

2010-01-01

448