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1

Microbial Ecology of an Extreme Acidic Environment, the Tinto River  

Microsoft Academic Search

The Tinto River (Huelva, southwestern Spain) is an extreme environment with a rather constant acidic pH along the entire river and a high concentration of heavy metals. The extreme conditions of the Tinto ecosystem are generated by the metabolic activity of chemolithotrophic microorganisms thriving in the rich complex sulfides of the Iberian Pyrite Belt. Molecular ecology techniques were used to

E. Gonzalez-Toril; E. Llobet-Brossa; E. O. Casamayor; R. Amann; R. Amils

2003-01-01

2

Can Tinto's Student Departure Model Be Applied To Nontraditional Students?  

Microsoft Academic Search

While Tinto's student departure model has been tested and supported in numerous studies, it has not yet been applied to nontraditional students. This study attempted to find out whether Tinto's model, in particular the concepts of academic and social integration, can explain retention among nontraditional students. Attrition rates of 25 adult learner classes in a college of management and business

Hanna Ashar; Robert Skenes

1993-01-01

3

Environmental control of Tinto and Odiel river basins by PIXE  

NASA Astrophysics Data System (ADS)

A study of the elemental concentrations of sediments of the rivers Tinto and Odiel, in Huelva, Spain, has been performed using PIXE. Thirteen samples have been collected, seven in the Tinto and six in the Odiel. Concentrations of 19 elements have been determined in each of them. The analysis of the data illustrates the environmental impact of the mining and fertilizer plants in the area.

Respaldiza, M. A.; López-Tarrida, A. J.; Gómez-Camacho, J.

1993-04-01

4

Metal accumulation screening of the Río Tinto flora (Huelva, Spain).  

PubMed

Río Tinto (Huelva, Spain) is located in one of the most important mining regions in the world. Its soils are characterized by their extreme acidity and elevated concentrations of heavy metals. Due to these characteristics, the Tinto ecosystem is considered unique and an ideal location to study biological adaptations to this type of habitat. Plant species that present these adaptations might be useful to mining and other metal pollution restoration programs. This study reports the results for the screening of Ca, Mg, Na, Mn, Fe, Ni, Cu, Zn, As, and Pb in aerial tissues of 97 plant species from the Tinto basin flora. In addition, plant-soil relationships were analyzed using the biological absorption coefficient (BAC) to detect the main plant adaptations in the Tinto flora. The species selected are representative of the biomass of the main dominant edaphophile and climatophile vegetation communities of the three river sections, forest, and subseral stages. Plant and soil elemental analyses were performed using inductively coupled plasma-mass spectrometry technique (ICP-MS). The results indicate that in general, Tinto flora shows a pattern of accumulation of the analyzed elements in aerial tissues which agrees with the nutritional requirements of vascular plants (macronutrients > micronutrients > indifferent or toxic elements). Among macronutrients, Ca seems to be an essential element in this habitat. This element accumulates in the aerial plant tissues. Basically, the Río Tinto flora is made of Fe, Cu, Zn, Ni, As, and Pb excluders, although some analyzed species of Erica, Quercus, Lavandula, Cistus, Genista, and Cytisus genera can be considered Mn accumulators. The results of this study make up a body of fundamental knowledge of the strategies used by plants to thrive in habitats with high concentrations of toxic heavy metals. This information is vital when it comes to planning a restoration program. Plants must be selected and used according to the requirements, always respecting the characteristics of the territory and facilitating the development of suitable vegetation. PMID:19669116

de la Fuente, Vicenta; Rufo, Lourdes; Rodríguez, Nuria; Amils, Ricardo; Zuluaga, Javier

2009-08-08

5

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

6

Rio Tinto estuary (Spain): 5000 years of pollution  

Microsoft Academic Search

Mining of massive sulfide deposits in southwestern Spain extending back to the Copper and Bronze Ages has resulted in the\\u000a pollution of the Rio Tinto fluvial-estuarine complex, the site of Columbus' departure for the New World in 1492. Additional\\u000a sources of potential pollution include the large industrial complex at Huelva near the lower portion of the estuary. Extensive\\u000a analysis of

R. A. Davis Jr.; A. T. Welty; J. Borrego; J. A. Morales; J. G. Pendon; Jeffrey G Ryan

2000-01-01

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

Geochemistry of acidic Rio Tinto headwaters and role of bacteria in solid phase metal partitioning  

Microsoft Academic Search

Mining operations in the Rio Tinto area, southwest Spain, have created a historical pollution problem in the river and estuary. The fate of metals along the Rio Tinto river and estuary has been previously characterized, but little is known about transport and behaviour of metals and other elements in the headwaters of the river. The headwaters are situated approximately 100

F. G. Ferris; L. Hallbeck; C. B. Kennedy; K. Pedersen

2004-01-01

9

Mineralogy and geochemistry of alluvium contaminated by metal mining in the Rio Tinto area, southwest Spain  

Microsoft Academic Search

The Rio Tinto in SW Spain drains Cu and pyrite mines which have been in operation since at least the Bronze Age. Extensive metal mining, especially from 1873 to 1954, has resulted in contamination of the Rio Tinto alluvium with As, Cu, Pb, Ag and Zn. X-ray diffraction (XRD), wavelength-dispersive X-ray mapping, scanning electron microscope petrography and X-ray energy-dispersive (EDX)

Karen A Hudson-Edwards; Christiane Schell; Mark G Macklin

1999-01-01

10

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

Microsoft Academic Search

The Tinto and Odiel rivers drain 100 km from the Rio Tinto sulphide mining district, and join at a 20-km long estuary entering\\u000a the Atlantic Ocean. A reconnaissance study of heavy metal anomalies in channel sand and overbank mud of the river and estuary\\u000a by semi-quantitative emission dc-arc spectrographic analysis shows the following upstream to downstream ranges in ppm (?g

C. H. Nelson; P. J. Lamothe

1993-01-01

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

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

PubMed

We studied the correlation between physicochemical and biological characteristics of an acidic river, the Tinto River, in Southwestern Spain. The Tinto River is an extreme environment characterized by its low pH (mean of 2.2) and high concentrations of heavy metals (Fe 2.3 g/L, Zn 0.22 g/L, Cu 0.11 g/L). These extreme conditions are the product of the metabolic activity of chemolithotrophic microorganisms, including iron- and sulfur-oxidizing bacteria, that can be found in high concentrations in its waters. The food chain in the river is very constrained and exclusively microbial. Primary productivity in the Tinto River is the sum of photosynthetic and chemolithotrophic activity. Heterotrophic bacteria and fungi are the major decomposers and protists are the major predators. A correlation analysis including the physicochemical and biological variables suggested a close relationship between the acidic pH values and abundance of both chemolithotrophic bacteria and filamentous fungi. Chemolithotrophic bacteria correlated with the heavy metals found in the river. A principal component analysis of the biotic and abiotic variables suggested that the Tinto River ecosystem can be described as a function of three main groups of variables: pH values, metal concentrations, and biological productivity. PMID:11252161

López-Archilla, A.I.; Marin, I.; Amils, R.

2001-01-01

13

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

14

Contrasting Microbial Community Assembly Hypotheses: A Reconciling Tale from the Río Tinto  

Microsoft Academic Search

BackgroundThe 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

Carmen Palacios; Erik Zettler; Ricardo Amils; Linda Amaral-Zettler; Niyaz Ahmed

2008-01-01

15

Contrasting Microbial Community Assembly Hypotheses: A Reconciling Tale from the Río Tinto  

Microsoft Academic Search

Background: The Rio 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

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

2008-01-01

16

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

Microsoft Academic Search

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

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

2008-01-01

17

Methanogenesis in the sediments of Rio Tinto, an extreme acidic river.  

PubMed

Río Tinto (Iberian Pyritic Belt, SW Spain) is well known for its low pH (mean pH 2.3), high redox potential (> +400 mV) and high concentration of heavy metals. In this work we describe and analyse the presence of methanogenic archaea in the extreme acidic and oxidizing environment of the Tinto basin. Methane formation was measured in microcosms inoculated with sediments from the Rio Tinto basin. Methanol, formate, volatile fatty acids and lactate stimulated the production of methane. Methane formation was associated with a decrease of redox potential and an increase in pH. Cores showed characteristic well-defined black bands in which a high acetate concentration was measured among the otherwise reddish-brown sediments with low acetate concentration. Methanosaeta concilii was detected in the black bands. In enrichment cultures, M. concilii (enriched with a complex substrate mixture), Methanobacterium bryantii (enriched with H(2)) and Methanosarcina barkeri (enriched with methanol) were identified. Our results suggest that methanogens thrive in micro-niches with mildly acidic and reducing conditions within Rio Tinto sediments, which are, in contrast, immersed in an otherwise extremely acidic and oxidizing environment. PMID:21605308

Sanz, José L; Rodríguez, Nuria; Díaz, Emiliano E; Amils, Ricardo

2011-05-23

18

Analysis of As, Pb, Fe, and Co in the Rio Tinto Estuary in Southwest Spain.  

National Technical Information Service (NTIS)

Spurred on by the trace metal contamination in the Mediterranean Sea, a possible source of this has been pursued by examining the Rio Tinto estuary in the southwest of Spain. Using the AA and the ICPMS, five metals were investigated to observe mixing in t...

J. A. Vatland

1996-01-01

19

Contributo para Adaptação Transcultural do Instrumento de Medida - Injury Report Form IRB 2007 - para a Realidade Portuguesa - Validade De Conteúdo  

Microsoft Academic Search

Introduction: The high incidence of rugby injuries in Portugal justifies the use of a form including updated methods and definitions. Objective: Proceed a transcultural adaptation (TCA) of the Injury Report Form iRB 2007 to the Portuguese population and corresponding content validation. Relevance: In Portugal, only one TCA record exists in Rugby, performed by physiotherapists in 2003. Methods: The methods used

Pedro Gomes; Bruno Neves

2009-01-01

20

Subsurface Geomicrobiology of a Volcanically Hosted Massive Sulfide Deposit (VHMS), Near Rio Tinto, Spain  

Microsoft Academic Search

Background. We investigated a subsurface lithotrophic microbial ecosystem in a volcanically hosted massive sulfide deposit (VHMS) of the Iberian Pyrite Belt. These extremely reactive rocks persist only because they are sequestered from the atmosphere. The Rio Tinto, in SW Spain is a 100 km-long ARD stream with extreme pH (ca. 2.3) and metal loading (> 2.5 gm\\/l). Springs feeding the

T. O. Stevens; R. Amils; C. Stoker; D. Fernandez-Remolar; J. Gomez-Elvira

2005-01-01

21

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

SciTech Connect

The Tinto and Odiel river drain 100 km from the Rio Tinto sulphide mining district and join at a 20-km estuary entering the Atlantic Ocean. A reconnaissance study of heavy metal anomalies in channel sand and overbank mud of the river and estuary shows the following upstream to downstream ranges in ppm ([mu]g g[sup [minus]1]): As 3,000 to <200, Cd 30 to <0.1, Cu 1,500 to 10, Pb 2,000 to <10, Sb 300 to <150, and Zn 3,000 to <200. Organic-rich sandy-silty 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 river bed sand has been analyzed to represent bedload transport of naturally-occurring sulfide minerals. The sand has high concentrations of metals upstream, decreasing by 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. 36 refs., 8 figs., 4 tabs.

Nelson, C.H.; Lamothe, P.J. (Geological Survey, Menlo Park, CA (United States))

1993-12-01

22

Development and Structure of Eukaryotic Biofilms in an Extreme Acidic Environment, Río Tinto (SW, Spain)  

Microsoft Academic Search

An in situ colonization assay was performed to study the early stages of biofilm formation in Ro Tinto (SW, Spain), an extremely acidic\\u000a environment (pH ca. 2). Eukaryotic assemblages were monitored at monthly intervals for 1 year. Diversity, colonization rates,\\u000a and seasonal variations were analyzed. Structural features of naturally grown biofilms were explored by light and scanning\\u000a electron microscopy in

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

2007-01-01

23

The Rio Tinto Mars analogue site: an extremophilic Raman spectroscopic study.  

PubMed

The Rio Tinto site is recognised as a terrestrial Mars analogue because of the presence of jarosite and related sulfates which have recently been identified by the NASA Mars Exploration Rover "Opportunity" in the El Capitan region of Meridiani Planum on Mars. It has long been known that acidophilic microbial action is responsible for the deep blood-red colour of the water in Rio Tinto, where the pH varies from about 1.5 to 3.0 and the water is rich in iron and sulfur. Following recent Raman spectroscopic characterisation of the mineral phases of the Rio Tinto system, we report here a study of the biological components found in several specimens of deposited minerals and near the waterside that were collected during a GeoRaman VI Conference organized field trip in 2006. Key biosignatures were found for carotenoids, scytonemin and mycosporine-like amino acids, which are indicative of the biological colonisation of exposed mineral substrates; information from this study will be useful for targeting Martian sites using a miniaturized Raman instrument where the biosignatures of relict or extant life could remain in the geological record. PMID:17600759

Edwards, Howell G M; Vandenabeele, Peter; Jorge-Villar, Susana E; Carter, Elizabeth A; Perez, Fernando Rull; Hargreaves, Michael D

2007-04-19

24

Screening of anaerobic activities in sediments of an acidic environment: Tinto River.  

PubMed

The Tinto River (Huelva, Spain) is a natural acidic rock drainage environment produced by the bio-oxidation of metallic sulfides from the Iberian Pyritic Belt. A geomicrobiological model of the different microbial cycles operating in the sediments was recently developed through molecular biological methods, suggesting the presence of iron reducers, methanogens, nitrate reducers and hydrogen producers. In this study, we used a combination of molecular biological methods and targeted enrichment incubations to validate this model and prove the existence of those potential anaerobic activities in the acidic sediments of Tinto River. Methanogenic, sulfate-reducing, denitrifying and hydrogen-producing enrichments were all positive at pH between 5 and 7. Methanogenic enrichments revealed the presence of methanogenic archaea belonging to the genera Methanosarcina and Methanobrevibacter. Enrichments for sulfate-reducing microorganisms were dominated by Desulfotomaculum spp. Denitrifying enrichments showed a broad diversity of bacteria belonging to the genera Paenibacillus, Bacillus, Sedimentibacter, Lysinibacillus, Delftia, Alcaligenes, Clostridium and Desulfitobacterium. Hydrogen-producing enrichments were dominated by Clostridium spp. These enrichments confirm the presence of anaerobic activities in the acidic sediments of the Tinto River that are normally assumed to take place exclusively at neutral pH. PMID:22956355

Sánchez-Andrea, Irene; Rojas-Ojeda, Patricia; Amils, Ricardo; Sanz, José Luis

2012-09-07

25

Fossilization potential of iron-bearing minerals in acidic environments of Rio Tinto, Spain: Implications for Mars exploration  

NASA Astrophysics Data System (ADS)

Acidic waters of the Rio Tinto, southwestern Spain, evaporate seasonally, precipitating a variety of iron sulfide and oxide minerals. Schwertmannite and nanophase goethite form thin laminae on biological and detrital grain surfaces, replicating, among other things, the morphologies of insect cuticle, plant tissues, fungi, algae, and bacteria. Intergrain cements also incorporate bacterial cells and filaments. Other sulfate minerals precipitated in Rio Tinto environments are transient and contribute little to short-term preservation. Because the Rio Tinto has been cutting its current valley for several million years, terrace deposits provide a window on longer term fossil preservation. Early and later diagenesis are recorded in terrace deposits formed about one thousand and two million years ago, respectively. The sedimentary structures and mineralogies of these deposits suggest that they formed under physical and chemical conditions comparable to those of modern Rio Tinto sediments. The terrace deposits show quantitative loss of sulfate minerals, increasing crystallinity of goethite and, in the older terrace, replacement of goethite by hematite. Fossils formed originally by schwertmannite and nanophase goethite replication persist through diagenesis, preserving a long term record of local biological diversity. Fossil preservation by iron oxides in the acidic environment of Rio Tinto suggests that if life was present when sedimentary rocks formed at Meridiani Planum, Mars, precipitated minerals could record their presence.

Fernández-Remolar, David C.; Knoll, Andrew H.

2008-03-01

26

Classification of Modern and Old Río Tinto Sedimentary Deposits Through the Biomolecular Record Using a Life Marker Biochip: Implications for Detecting Life on Mars  

Microsoft Academic Search

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

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

2011-01-01

27

Geological record of an acidic environment driven by iron hydrochemistry: The Tinto River system  

NASA Astrophysics Data System (ADS)

The existence of possible hematitic strata on the surface of Mars demands a search for terrestrial analogues formed in unusual environments. This will help us to recognize and interpret environmental and, perhaps, biological signatures preserved in Mars' hematites. Such an analogue would allow us to establish valid reference systems based on geomicrobial and biogeochemical signatures. Two different aspects place the Tinto River inside the boundaries of a natural extreme system: its high level of biological diversity and the presence of fluvial rocks formed in the same acidic conditions as in the modern system, which could predate the Tertiary. Study of both the modern system and the ancient system is necessary to understand the formation of biosignatures. A chemolithotrophic community that biooxidizes the Iberian Pyritic Belt, acidifying water (pH between 0.9 and 3.0) and favoring high concentrations of ferric iron in solution (up to 20 g.L-1), maintains this iron-driven system. In spite of these extreme conditions, high microbial diversity was found. Its acidic bacteria, archaea, and eukarya constitute a complex community supported by algal biomass in highly stable hydrochemical conditions, which are achieved through iron buffering. The pH is maintained at constant low levels even at very high water dilution. In these conditions, iron minerals as oxyhydroxides, hydroxides, and sulfates are formed. The modern and recent parageneses contrast with the ancient Tinto River terrace mineral associations, which show dehydrated and desulfated iron oxides. If this dehydration process is considered, these Tinto River ironstones may be a key for knowing some aquatic habitats, which may have hosted a part of the early Mars biosphere.

Fernández-Remolar, David C.; Rodriguez, Nuria; Gómez, Felipe; Amils, Ricardo

2003-07-01

28

Ecological study of the fungal populations of the acidic Tinto River in southwestern Spain.  

PubMed

The characterization of the microbial ecology of the Tinto River, an extreme habitat with an extremely low pH and a high concentration of heavy metals, revealed an unexpected level of microbial richness. A variety of microbial eukaryotes was isolated, among them several fungal strains that were identified and their physiological characteristics studied. Ninety strains of yeast were isolated from the Tinto River. Fifty-two percent of them were capable of growth in vitro using medium amended with river water. They belong to 6 genera of basidiomycetes (Rhodotorula, Cryptococcus, Tremella, Holtermannia, Leucosporidium, and Mrakia) and 2 of ascomycetes (Candida and Williopsis). In addition, 349 strains of hyphomycetes belonging to 17 genera (most of them ascomycetes) were isolated and studied. Forty-four percent of the isolated filamentous fungi (154 strains) were capable of growing in vitro using medium amended with Tinto River water. Of this percentage, 19% (29 strains) belonged to the genus Penicillium (16 species) and 66% (102 strains) were included in the genera Scytalidium, Bahusakala, Phoma, and Heteroconium or showed dark sterile mycelia, which probably are of dematiaceous hyphomycetes. In addition, we characterized strains of the ascomycete genera Lecythophora and Acremonium and of the zygomycete genus Mortierella, all of them capable of growing in medium amended with river water. Statistical correlation of biological and physicochemical variables suggested a positive relationship between the dematiaceous hyphomycetes and the most extreme physicochemical conditions found in the Tinto River. Principal components analysis confirmed this relationship and also showed that the Acremonium and Lecythophora groups had environmental preferences similar to those of dematiaceous fungi. The spatial positions of the sampling sites were grouped in 2 main clusters: (i) sampling sites in the mine zone in which most of the dematiaceous, Acremonium, and Lecythophora strains were isolated and (ii) sites that were not in the mine zone and sampling station 5 from which were isolated mainly strains of fungi that were not capable of growing in the medium amended with river water and species of the Penicillium genus. PMID:15644909

López-Archilla, A I; González, A E; Terrón, M C; Amils, R

2004-11-01

29

Microbial sulfur isotope fractionation in a Mars analogue environment at Rio Tinto, SW Spain  

NASA Astrophysics Data System (ADS)

Abundant sulfate minerals are present on Mars hence sulfur isotopes are likely to be a key tool for the detection of any past or present life. To investigate the link between the activity of sulfate reducing microorganisms and sulfur isotope fractionation, we incubated sediments from a modern hyper-acidic, Ferich subareal environment at Rio Tinto, SW Spain. This site has been frequently used as a geochemical analogue of Mars. Sediments were sampled from the upper part of Rio Tinto (Marismilla) and the estuary (Moguer). Laboratory incubations were carried out at 30°C, using an artificial input solution with sulfate in excess [1]. Electron donors were provided by the natural substrate. Initial data indicate moderate biological sulfate reduction rates of between 5 and 90 nmol·cm-3·h-1 both in Marismilla and in Moguer, independent of the pH of the input solution. Sulfur isotope fractionation was extreme in the Moguer estuary, extending beyond the maximum of 47‰ predicted by the standard Rees model [2]. These data indicate that sulfur isotopes have a potential to be sensitive indicators of biotic activity in Martian environments containing sulfate minerals.

Velasco, E.; Mason, P.; Vroon, P.; Röling, W.; Davies, G.

2011-10-01

30

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

31

Inverting the impacts: Mining, conservation and sustainability claims near the Rio Tinto\\/QMM ilmenite mine in Southeast Madagascar  

Microsoft Academic Search

This paper traces a genealogy of land access and legitimization strategies culminating in the current convergence of mining and conservation in Southeast Madagascar, contributing to recent debates analyzing the commonalities and interdependencies between seemingly discrete types of land acquisitions. Drawing upon research carried out near the Rio Tinto\\/QMM ilmenite mine in 2009 (January–March), it focuses on how local Malagasy land

Caroline Seagle

2012-01-01

32

Integrated remote sensing and GIS techniques for biogeochemical characterization of the Tinto-Odiel estuary system, SW Spain  

Microsoft Academic Search

The Tinto-Odiel estuary area in SW Spain presents a high concentration of industrial, agricultural and mining activities that seriously affect water quality, producing significant concentrations in trace metals and other contaminant elements. Previous studies have highlighted the important environmental effect of these contaminated waters discharged into the Gulf of Cadiz, contributing in a marked way to trace-metal concentrations in the

M. Chica-Olmo; F. Rodriguez; F. Abarca; J. P. Rigol-Sanchez; E. deMiguel; J. A. Gomez; A. Fernandez-Palacios

2004-01-01

33

Microbial sulphur isotope fractionation in a Mars analogue environment at Rio Tinto, SW Spain  

NASA Astrophysics Data System (ADS)

The development of geochemical proxies for possible early life on Mars is important in preparation for future space missions, especially those that will return samples to Earth. Sulfur isotopes are likely to be a key future tool for this purpose since abundant sulphate minerals on the surface of Mars [1], such as jarosite (KFe3+3(SO4)2(OH)6), may record the activity of sulphur metabolizing microorganisms. Little is currently known about the sulphur isotope effects associated with sulphate reduction in the acidic environments where jarosite and other minerals are likely to have precipitated. Here we investigate the relationship between sulphate reducing activity and sulphur isotope fractionation in a modern hyper-acidic subareal environment at Rio Tinto, SW Spain [2,3,4]. The geochemical characteristics of Rio Tinto are the consequence of modern weathering of pyrite-rich ores in the Iberian Pyritic Belt, and the metabolism of iron and sulphur compounds by chemolithotrophic microorganisms. This results in a high concentration of ferric iron that is soluble under the acidic conditions generated by the biological activity. These conditions cause the precipitation of ferric-bearing minerals, including amorphous phases and hydronium jarosite. Sulphate reducing bacteria have recently been isolated from Rio Tinto sediments despite the fact that high concentrations of ferrous iron can inhibit microbial sulphate reduction. Flow-through reactor experiments were performed using sediment samples from Río Tinto, in localities where the potential for sulphate-reducing activity was previously identified. Sediments were taken both in the upper part of the river and in the estuary where tidal effects have created a dynamic environment, with mixing between hyperacidic and marine conditions. Sediments were incubated in the laboratory at 30oC, using an artificial input solution with sulphate in excess using techniques developed by Stam et al. [5]. Two sets of experiments were done at pH 7 and pH 3 with electron donors provided by the natural substrate. Duplicate reactors were incubated for a total of 10 weeks. Initial data indicate moderate potential sulfate reduction rates of between 5 and 45 nM cm-3 h-1 at both pH 7 and pH 3. Isotope effects will be determined by measuring differences in ?34S between the sulphate in the inflow and outflow solutions. We expect our results to further help in the targeting of sampling sites in the search for traces of life on Mars. References: [1] Van Zuilen, M. (2008). Space Science Reviews 135(1-4): 221-232 [2] Amils, R., et al. (2007), Planetary and Space Science 55, 370-381. [3] Fernández-Remolar, D., et al., (2005), Earth and Planetary Science Letters 240 (2005) 149-167. [4] Mumma, M. J., et al., (2009), Science, Vol 323, pag 1041-1045. [5] Stam, M.C., et al., (2008). Geochim. Cosmochim. Acta 72: A891.

Velasco, Esther; Mason, Paul; Gonzalez-Toril, Elena; Zegers, Tanja; Davies, Gareth; Amils, Ricardo

2010-05-01

34

The Río Tinto Basin, Spain: Mineralogy, sedimentary geobiology, and implications for interpretation of outcrop rocks at Meridiani Planum, Mars  

NASA Astrophysics Data System (ADS)

Exploration by the NASA rover Opportunity has revealed sulfate- and hematite-rich sedimentary rocks exposed in craters and other surface features of Meridiani Planum, Mars. Modern, Holocene, and Plio-Pleistocene deposits of the Río Tinto, southwestern Spain, provide at least a partial environmental analog to Meridiani Planum rocks, facilitating our understanding of Meridiani mineral precipitation and diagenesis, while informing considerations of martian astrobiology. Oxidation, thought to be biologically mediated, of pyritic ore bodies by groundwaters in the source area of the Río Tinto generates headwaters enriched in sulfuric acid and ferric iron. Seasonal evaporation of river water drives precipitation of hydronium jarosite and schwertmannite, while (Mg,Al,Fe 3+)-copiapite, coquimbite, gypsum, and other sulfate minerals precipitate nearby as efflorescences where locally variable source waters are brought to the surface by capillary action. During the wet season, hydrolysis of sulfate salts results in the precipitation of nanophase goethite. Holocene and Plio-Pleistocene terraces show increasing goethite crystallinity and then replacement of goethite with hematite through time. Hematite in Meridiani spherules also formed during diagenesis, although whether these replaced precursor goethite or precipitated directly from groundwaters is not known. The retention of jarosite and other soluble sulfate salts suggests that water limited the diagenesis of Meridiani rocks. Diverse prokaryotic and eukaryotic microorganisms inhabit acidic and seasonally dry Río Tinto environments. Organic matter does not persist in Río Tinto sediments, but biosignatures imparted to sedimentary rocks as macroscopic textures of coated microbial streamers, surface blisters formed by biogenic gas, and microfossils preserved as casts and molds in iron oxides help to shape strategies for astrobiological investigation of Meridiani outcrops.

Fernández-Remolar, David C.; Morris, Richard V.; Gruener, John E.; Amils, Ricardo; Knoll, Andrew H.

2005-11-01

35

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

2013-04-16

36

Subsurface Geomicrobiology of a Volcanically Hosted Massive Sulfide Deposit (VHMS), Near Rio Tinto, Spain  

NASA Astrophysics Data System (ADS)

Background. We investigated a subsurface lithotrophic microbial ecosystem in a volcanically hosted massive sulfide deposit (VHMS) of the Iberian Pyrite Belt. These extremely reactive rocks persist only because they are sequestered from the atmosphere. The Rio Tinto, in SW Spain is a 100 km-long ARD stream with extreme pH (ca. 2.3) and metal loading (> 2.5 gm/l). Springs feeding the river are already metal-laden, yet their pH can range to 6 and many are anoxic. We hypothesized that subsurface biological activity contributes to the weathering of the VHMS, and that anaerobic metabolism, using in situ electron acceptors was a major component of this putative underground bioreactor. Methods. We aseptically sampled rocks and ground-waters up-gradient from the VHMS, within the VHMS, and down- gradient from the VHMS through springs and continuously-cored boreholes. Samples were analyzed for the presence of microorganisms, resources that might support microbial activity, and metabolites produced by microbial activity. Results. Organisms detected included aerobic Fe and S oxidizers, anaerobic denitrifying S2O32-oxidizers, and SO42--reducing and methanogenic H2 oxidizers. Ground water up- gradient from the VHMS was neutral, aerobic and low in solutes. Within the VHMS, H2 at concentrations up to 1000 ppm was produced by water-rock reactions. Anoxically leached ore produced pH 5-6 solutions containing Fe(II), Fe(III), SO42- and NO2-. Incoming O2 reacted to form NOx gases and pH 3.5 fluids. Low CH4 throughout the VHMS, indicated widespread anoxia. Down-gradient from the VHMS, ground waters were anoxic low-SO42- high- CH4 (5000 ppm) fluids or low- CH4 high- SO42- (800 ppm) fluids with abundant FeS precipitates. Generally, Fe(III) and H2 decreased along the flow path while Fe(II) and CH4 increased. NOx and SO42- concentrations remained relatively constant along the flow path. Conclusions. A subsurface ecosystem driven by weathering of sulfide minerals is present beneath the Rio Tinto region. An unexpected variety of resources are available to drive microbial metabolism, including electron donors and electron acceptors supplied from the rock matrix. Production of H2 from water-rock interactions within the ore body supported profuse activity of H2-oxidizing microorganisms including methane generation. The variety of fluids discharged from springs is apparently due to the various pathways groundwater may take through the fractured rock environment, and mixing with aerobic water. However, many of the activities observed appear to be independent of resources from the surface.

Stevens, T. O.; Amils, R.; Stoker, C.; Fernandez-Remolar, D.; Gomez-Elvira, J.

2005-12-01

37

Novel acid resistance genes from the metagenome of the Tinto River, an extremely acidic environment.  

PubMed

Microorganisms that thrive in acidic environments are endowed with specialized molecular mechanisms to survive under this extremely harsh condition. In this work, we performed functional screening of six metagenomic libraries from planktonic and rhizosphere microbial communities of the Tinto River, an extremely acidic environment, to identify genes involved in acid resistance. This approach has revealed 15 different genes conferring acid resistance to Escherichia coli, most of which encoding putative proteins of unknown function or previously described proteins not known to be related to acid resistance. Moreover, we were able to assign function to one unknown and three hypothetical proteins. Among the recovered genes were the ClpXP protease, the transcriptional repressor LexA and nucleic acid-binding proteins such as an RNA-binding protein, HU and Dps. Furthermore, nine of the retrieved genes were cloned and expressed in Pseudomonas putida and Bacillus subtilis and, remarkably, most of them were able to expand the capability of these bacteria to survive under severe acid stress. From this set of genes, four presented a broad-host range as they enhance the acid resistance of the three different organisms tested. These results expand our knowledge about the different strategies used by microorganisms to survive under extremely acid conditions. PMID:23145860

Guazzaroni, María-Eugenia; Morgante, Verónica; Mirete, Salvador; González-Pastor, José E

2012-11-12

38

Enrichment and isolation of acidophilic sulfate-reducing bacteria from Tinto River sediments.  

PubMed

Although some acidophilic and alkaliphilic species have been described recently, most of the known sulfate-reducing bacteria (SRB) grow optimally at neutral pH. In this study, sulfate reduction was studied with sediment samples from the extremely acidic Tinto River basin. Stable enrichments of SRB were obtained at pH?4 with glycerol, methanol and hydrogen; at pH?4.5 with lactate and at pH?5.5 with succinate as substrates. Inhibition of sulfate reduction by organic acids below their pKa was observed. Cloning and sequencing of 16S rRNA gene showed that fermentative bacteria (Paludibacter spp., Oscillibacter spp.) and SRB (Thermodesulfobium spp., Desulfosporosinus spp., Desulfitobacterium spp., Desulfotomaculum spp.) were co-enriched. By repeated serial dilutions and streaking on agar plates, four strains of SRB belonging to the Firmicutes phylum were obtained. Two of them show 96% 16S rRNA gene sequence similarity with Desulfosporosinus acidophilus, and a third one with Desulfosporosinus orientis. Another isolate has just 93% rRNA gene sequence similarity with the Desulfosporosinus/Desulfitobacterium cluster and might represent a novel species within a novel genus. One of the Desulfosporosinus strains was further investigated showing maximum growth at pH?5.5, and a pH-dependent inhibitory effect of organic acids and sulfide. PMID:24115617

Sánchez-Andrea, Irene; Stams, Alfons J M; Amils, Ricardo; Sanz, José Luis

2013-05-06

39

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

2013-07-28

40

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

41

Fluvial Bedform Generation by Biofilm Activity in the Berrocal Segment of Río Tinto: Acidic Biofilms and Sedimentation  

Microsoft Academic Search

\\u000a In the acidic environment of Río Tinto, there is a close relationship between microbial mat growth and channel configuration.\\u000a This extreme environment is characterized by solutions with a low pH (1–3) and high Eh (300–450 mV), and high concentration\\u000a in ferric iron (0.5–30 g l?1) and sulfates (1–120 g l?1). Under these conditions, biofilms have several morphologies that adapt to

David C. Fernández-Remolar; David Gómez-Ortíz; Olga Prieto-Ballesteros; Felipe Gómez; Ricardo Amils

42

Assessing The Value of Hydrological Ensemble Predictions for Rio Tinto Alcan's Hydropower System in Eastern Canada  

NASA Astrophysics Data System (ADS)

Rio Tinto Alcan (RTA) is a multinational aluminium producer with smelters in Quebec, Canada. RTA also owns and operates power houses on Péribonka and Saguenay Rivers. The system, which is run by RTA's Quebec Power Operations Division, consists of 6 generating stations and 3 major reservoirs, for an installed capacity of 2900 MW. One of the significant issues that had to be resolved for effective operation of this system was to determine the volume of water release per week for all generating stations. Several challenges had to be dealt with before a suitable solution could be found. Last year, RTA started a five year R&D project for improving the management of the hydropower system. This project includes data monitoring, hydrological ensemble prediction (HEP) and stochastic optimization methods. A concomitant presentation (submitted to HS5.7 by Cote et al.) describes the stochastic optimization project that aims to assess the value of using a stochastic solver instead of a deterministic one. Cote et al. evaluated two different stochastic optimization approaches: lag-1 Stochastic Dynamic Programming (SDP) and Sampling Stochastic Dynamic Programming (SSDP) algorithms. Both stochastic optimization methods use Hydrological Ensemble Prediction (HEP) to capture the spatio-temporal variability of the inflows. This presentation investigates the value of using different HEP procedures in the operation of RTA's hydropower system with stochastic optimization methods. More precisely, the value of using biased or unbiased HEP, the value of using HEP with a good representation or a misrepresentation of the predictive uncertainties were assessed using a test bench study that mimics real-world RTA's operations. The results indicate that in real world operations, biased HEP or under-dispersed HEP can void the gain obtained by stochastic optimization methods.

Latraverse1, M.; Cote, P.; Larouche1, B.

2012-04-01

43

Microbial community structure across the tree of life in the extreme R?o Tinto  

PubMed Central

Understanding biotic versus abiotic forces that shape community structure is a fundamental aim of microbial ecology. The acidic and heavy metal extreme Río Tinto (RT) in southwestern Spain provides a rare opportunity to conduct an ecosystem-wide biodiversity inventory at the level of all three domains of life, because diversity there is low and almost exclusively microbial. Despite improvements in high-throughput DNA sequencing, environmental biodiversity studies that use molecular metrics and consider entire ecosystems are rare. These studies can be prohibitively expensive if domains are considered separately, and differences in copy number of eukaryotic ribosomal RNA genes can bias estimates of relative abundances of phylotypes recovered. In this study we have overcome these barriers (1) by targeting all three domains in a single polymerase chain reaction amplification and (2) by using a replicated sampling design that allows for incidence-based methods to extract measures of richness and carry out downstream analyses that address community structuring effects. Our work showed that combined bacterial and archaeal richness is an order of magnitude higher than eukaryotic richness. We also found that eukaryotic richness was highest at the most extreme sites, whereas combined bacterial and archaeal richness was highest at less extreme sites. Quantitative community phylogenetics showed abiotic forces to be primarily responsible for shaping the RT community structure. Canonical correspondence analysis revealed co-occurrence of obligate symbionts and their putative hosts that may contribute to biotic forces shaping community structure and may further provide a possible mechanism for persistence of certain low-abundance bacteria encountered in the RT.

Amaral-Zettler, Linda A; Zettler, Erik R; Theroux, Susanna M; Palacios, Carmen; Aguilera, Angeles; Amils, Ricardo

2011-01-01

44

Acid mine drainage pollution in the Tinto and Odiel rivers (Iberian Pyrite Belt, SW Spain) and bioavailability of the transported metals to the Huelva Estuary  

Microsoft Academic Search

The Tinto and Odiel rivers are seriously affected by acid mine drainage (AMD) from the long-term mining activities in Iberian Pyrite Belt (IPB). As a consequence, the Huelva estuary is heavily contaminated by metals and metalloids. This study presents an estimation of the seasonal variation, and the dissolved contaminant load transported by both rivers from February 2002 to September 2004.

José Miguel Nieto; Aguasanta M. Sarmiento; Manuel Olías; Carlos R. Canovas; Inmaculada Riba; Judit Kalman; T. Angel Delvalls

2007-01-01

45

Acid mine drainage pollution in the Tinto and Odiel rivers (Iberian Pyrite Belt, SW Spain) and bioavailability of the transported metals to the Huelva Estuary  

Microsoft Academic Search

The Tinto and Odiel rivers are seriously affected by acid mine drainage (AMD) from the long-term mining activities in Iberian Pyrite Belt (IPB). As a consequence, the Huelva estuary is heavily contaminated by metals and metalloids. This study presents an estimation of the seasonal variation, and the dissolved contaminant load transported by both rivers from February 2002 to September 2004.

José Miguel Nieto; Aguasanta M. Sarmiento; Manuel Olías; Carlos R. Canovas; Inmaculada Riba; Judit Kalman; T. Angel Delvalls

2006-01-01

46

Assessing Stochastic Optimization for Rio Tinto Alcan's Hydropower System in Eastern Canada  

NASA Astrophysics Data System (ADS)

Rio Tinto Alcan (RTA) is a multinational aluminium producer with smelters in Quebec, Canada. RTA also owns and operates power houses on Péribonka and Saguenay Rivers. The system, which is run by RTA's Quebec Power Operations Division, consists of 6 generating stations and 3 major reservoirs, for an installed capacity of 2900 MW. One of the significant issues that had to be resolved for effective operation of this system was to determine the volume of water release per week for all generating stations. Several challenges had to be dealt with before a suitable solution could be found. Last year, RTA started a five year R&D project for improving the management of the hydropower system. This project includes data monitoring, Hydrological Ensemble Prediction (HEP) and stochastic optimization (SO) methods. Development of SO methods is particularly interesting for RTA since, until now, the decision making process has been based on a deterministic solver even if it is impossible to predict naturally contributed volumes with any accuracy beyond a few days. Moreover, the production at the generating stations follows a non-linear, non-convex function of turbine flow rates and water head. Both of these factors have the effect of requiring that the decision should be based upon solving a non-linear and non-convex stochastic optimization problem. The following presentation describes the first part of the SO project and aims to assess the value of using a stochastic solver instead of a deterministic solver. Two different SO approaches were evaluated: lag-1 Stochastic Dynamic Programming (SDP) and Sampling Stochastic Dynamic Programming (SSDP) algorithms. HEP are used to capture the spatio-temporal variability of the inflows. Scenarios are generated using a hydrological model (HM) by initialising the HM with the same initial conditions (hydrologic state variables). These hydrologic variables are estimated using real-time observations available for the catchment area. Inter-scenario variability is provided by using different sequences of meteorological observations entered into the HM. The scenarios are used to estimate the parameters of the auto-regressive model utilized by SDP and the hydrologic state variables are used to estimate the probability transition between scenarios required by the SSDP algorithm. The optimization methods were implemented in RTA's system and the results compared with the actual deterministic decision procedure. Methods were compared using a test bench into which were incorporated the characteristics of the facilities and the HEP database.

Cote, P.; Latraverse, M.; Leconte, R.; Larouche, B.

2012-04-01

47

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

48

Influence of sorption processes by iron oxides and algae fixation on arsenic and phosphate cycle in an acidic estuary (Tinto river, Spain)  

Microsoft Academic Search

Inorganic arsenic and phosphate distributions have been studied in the acidic mixing zone of the Tinto river in November 1996, June 1997, and April 1998. This mixing zone receives high inputs of As, PO3?4 and Fe in relation with acid mine drainage and run-off from phosphogypsum waste. In the early stage of mixing the dissolution of detritic Fe phases (pyrite

Francoise Elbaz-Poulichet; Claude Dupuy; Antonio Cruzado; Zoila Velasquez; Eric P. Achterberg; Charlotte B. Braungardt

2000-01-01

49

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

50

Assessment of phosphogypsum impact on the salt-marshes of the Tinto river (SW Spain): role of natural attenuation processes.  

PubMed

About 120 Mton of phosphogypsum from the fertiliser industry were stack-piled on the salt-marshes of the Tinto river (Spain). This paper investigates the capacity of salt-marshes to attenuate contamination due to downward leaching from phosphogypsum. Solids and pore-waters were characterized at different depths of the pile to reach the marsh-ground. In superficial zones, metals were highly mobile, and no reduced sulphur was found. However, pollutant concentration decreased in the pore-water in deeper oxygen-restricted zones. Metal removal occurred by precipitation of newly formed sulphides, being this process main responsible for the contamination attenuation. Pyrite-S was the main sulphide component (up to 2528 mg/kg) and occurred as framboids, leading to high degrees of pyritization (up to 97%). The sulphidization reaction is Fe-limited; however, excess of acid-volatile sulphide over other metals cause precipitation of other sulphides, mainly of Cu and As. This decrease in metal mobility significantly minimises the impact of phosphogypsums on the salt-marshes. PMID:21992931

Pérez-López, Rafael; Castillo, Julio; Sarmiento, Aguasanta M; Nieto, José M

2011-10-10

51

Classification of Modern and Old Río Tinto Sedimentary Deposits Through the Biomolecular Record Using a Life Marker Biochip: Implications for Detecting Life on Mars  

NASA Astrophysics Data System (ADS)

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 0.3-0.5g 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.

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

52

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

53

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

54

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

55

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

56

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

57

The subsurface geology of Río Tinto: material examined during a simulated Mars drilling mission for the Mars Astrobiology Research and Technology Experiment (MARTE).  

PubMed

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 undisclosed 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. PMID:19105757

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

2008-10-01

58

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

59

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

60

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

61

Contributo allo sviluppo del calcolo analogico  

Microsoft Academic Search

\\u000a Summary  \\u000a Part I.—Automatic programming techniques for analogue computers.\\u000a \\u000a \\u000a Part II.—Hybrid techniques and related applications.\\u000a \\u000a \\u000a \\u000a \\u000a Part III.—Analogue vs. digital techniques.\\u000a \\u000a \\u000a \\u000a \\u000a Part I\\u000a \\u000a \\u000a \\u000a \\u000a APACHE cole is presented and its related subrontines:\\u000a \\u000a \\u000a \\u000a – \\u000a \\u000a - for automatic setting of fixed and variable delay functions (PADE' approximations)\\u000a \\u000a \\u000a \\u000a \\u000a – \\u000a \\u000a - for automatic setting of arbitrary, nonlinear functions of one variable (LAGRANGE approximations) CALonl FUnction GENeration.\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a \\u000a \\u000a \\u000a \\u000a CRESSIDA

G. P. Caligiuri

1966-01-01

62

Para Agricultores  

Center for Food Safety and Applied Nutrition (CFSAN)

Text Version... P. ¿Qué pasaría si las granjas se las ven diciles para cumplir con los requerimientos finales? ¿Se puede per- mir empo extra? ... More results from www.fda.gov/downloads/food/guidanceregulation

63

Contributo sulla diagnosi esofagogastroscopica nelle emorragie digestive alte in atto  

Microsoft Academic Search

Riassunto  Le nostre considerazioni conclusive possono così riassumersi:\\u000a \\u000a \\u000a 1o \\u000a Nelle emorragie esofago-gastriche l'esame endoscopico rappresenta il mezzo più appropriato e più rapido per formulare una\\u000a diagnosi di natura e di sede, mettendo talora in evidenza lesioni sanguinanti che, per la loro superficialità e per la loro\\u000a posizione, non sarebbero visibili con nessun'altro mezzo diagnostico.\\u000a \\u000a \\u000a \\u000a 2o \\u000a Rispetto ad altri procedimenti diagnostici l'endoscopia

E. Fiorini; A. Fratton; F. Polettini

1971-01-01

64

Seguridad alimentaria para futuras mamás: Seguridad ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... Seguridad alimentaria para futuras mamás: Seguridad alimentaria para toda la vida. Seguridad alimentaria para futuras ... More results from www.fda.gov/food/foodborneillnesscontaminants/peopleatrisk

65

Orientação para o Setor Hortifrutícola Guia para Minimização ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... Significa a aplicação cumulativa de calor ou produtos químicos em superfícies de contato com alimento limpas, que é suficiente para reduzir as ... More results from www.fda.gov/food/guidanceregulation/guidancedocumentsregulatoryinformation

66

Produce para-xylene economically  

SciTech Connect

During the last three years, some startling changes have occurred in the para-xylene market. Faced with a steady growth in demand and a shortfall in supply, the market saw spot and contract prices rise from $400/MT to historically high levels of $2,000 and $800/MT, respectively. This increase propelled the installation of a significant amount of new capacity in the form of grassroots units and expansions of existing facilities. In the first half of 1996, destocking downstream in the polyester chain began to soften the demand for para-xylene. This destocking, coupled with more aggressive positions being taken by buyers in anticipation of new capacity coming on-stream, caused para-xylene prices to fall almost as precipitously as they rose. Although the fundamental drivers for para-xylene demand remain strong, para-xylene producers are again in the position of having to compete for market share on the basis of product quality, low cost of production, and economics of scale. This situation is exacerbated by tight feedstock supply and the changing demand for some of the key byproducts of para-xylene production.

D`Auria, J.H.; Stoodt, T.J. [UOP, Des Plaines, IL (United States)

1997-04-01

67

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.

68

Proyecto para prestación de servicios \\  

Microsoft Academic Search

Esta presentación fue expuesta durante el Tercer Encuentro Técnico de Capacitación en Materia de Estructuración de Proyectos de Asociación Público-Privada, llevado a cabo en Mérida, Yucatán, México, el 20, 21 y 22 de enero de 2010. El Plan de Desarrollo del Estado de México 2005-2011 establece que se debe generar un acceso de calidad a los servicios de salud, para

Miguel Donovan

2010-01-01

69

Seguridad alimentaria para futuras mamás: Seguridad ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... alimentaria para futuras mamás: Seguridad alimentaria para futuras mamás: Alimentos seguros - Comer fuera y llevar comida preparada a casa. ... More results from www.fda.gov/food/foodborneillnesscontaminants/peopleatrisk

70

Seguridad alimentaria para futuras mamás: Alimentos ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... “Escuché hablar acerca de la Listeria en relación con el embarazo. ¿Qué hace que esta bacteria sea más nociva para mí y para mi bebé que otras ... More results from www.fda.gov/food/foodborneillnesscontaminants/peopleatrisk

71

[Standardization of di-chlor-di-para-xylilene, di-bromine-di-para-xylilene and di-para-xylilene].  

PubMed

Studied were the new components of dielectric coatings: di-para-xylilene, di-bromine-di-para-xylilene, dichlor-di-para-xylilene, which manifested themselves as low-toxicity compounds free from irritating, sensitizing and fibrogenous effects. The acute action thresholds for aerosols of the paraxylilenes were established at 10 mg/m3 (with regard to general and embryotoxicity), at 5 mg/m3 for the maximal inactive concentrations. PMID:1817083

Frolova, A D; Minkina, N A; Vasil'kovski?, V G; Kuznetsova, O A; Dolgopolova, E L; Shaposhnikova, E S; Martinson, T G

1991-01-01

72

?-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

73

Seguridad alimentaria para futuras mamás: Puntos ...  

Center for Food Safety and Applied Nutrition (CFSAN)

Eventos de otoño ¡Bienvenida al otoño, la época para celebrar la cosecha, Halloween, el Día de Acción de Gracias y sus eventos deportivos ... More results from www.fda.gov/food/foodborneillnesscontaminants/peopleatrisk

74

Orientación preliminar para la industria: Preguntas y ...  

Center for Food Safety and Applied Nutrition (CFSAN)

Text Version... de: Oficina de Seguridad de los Alimentos, Comunicación y Respuesta ante una Emergencia, HFS-005 Centro para la Seguridad Alimentaria y la ... More results from www.fda.gov/downloads/food/guidanceregulation

75

10. Apéndice B: Requisitos adicionales para nutrientes ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... Afirmaciones que utilizan el término "antioxidante". Para las afirmaciones que caracterizan el nivel de nutrientes antioxidantes de un alimento: ... More results from www.fda.gov/food/guidanceregulation/guidancedocumentsregulatoryinformation

76

Seguridad alimentaria para futuras mamás: Puntos ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... En épocas de calor, coloque los comestibles en el compartimiento para pasajeros con aire acondicionado de su auto en lugar de hacerlo en la ... More results from www.fda.gov/food/foodborneillnesscontaminants/peopleatrisk

77

Seguridad alimentaria para futuras mamás: Seguridad ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... nocivas se multipliquen. En agua fría. Cambie el agua cada media hora para mantener el agua fría. Usando el microondas ... More results from www.fda.gov/food/foodborneillnesscontaminants/peopleatrisk

78

Seguridad alimentaria para futuras mamás: Recursos  

Center for Food Safety and Applied Nutrition (CFSAN)

... Seguridad alimentaria para futuras mamás, Aquí encontrará información de contacto y una lista de enlaces a sitios Web sobre seguridad ... More results from www.fda.gov/food/foodborneillnesscontaminants/peopleatrisk

79

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.

80

SSH-Enabled ParaView  

Microsoft Academic Search

ParaView is a very powerful visualization tool used by many in the Department of Defense (DoD) high performance computing (HPC) community. It is both fast and flexible. It performs well on a user's desktop, but it can also scale to take advantage of clusters and large shared memory machines. Recently, ParaView has been adapted to run on the Linux clusters

Joel P. Martin; Rhonda J. Vickery; S. Ziegeler; R. Angelini

2009-01-01

81

Process for para-ethyltoluene dehydrogenation  

SciTech Connect

A process is described of dehydrogenating para-ethyltoluene to selectively form para-methylstyrene comprising contacting to para-ethyltoluene under dehydrogenation reaction conditions with a catalyst composition comprising: (a) from about 30% to 60% by weight of iron oxide, calculated as ferric oxide; (b) from about 13% to 48% by weight of a potassium compound, calculated as potassium oxide; and (c) from about 0% to 5% by weight of a chromium compound, calculated as chromic oxide. The improvement is described comprising dehydrogenating the para-ethyltoluene with a catalyst composition comprising, in addition to the components (a), (b) and (c), a modifying component (d) capable of rendering the para-methylstyrene-containing dehydrogenation reaction effluent especially resistant to the subsequent formation of popcorn polymers when the dehydrogenation of para-ethyltoluene is conducted over the modified catalyst, the modifying component (d) being a bismuth compound present to the extent of from about 1% to 20% by weight of the catalyst composition, calculated as bismuth trioxide.

Chu, C.C.

1986-06-03

82

Desenvolvimento de ímãs para sensor de velocidade para motor de arranque de avião  

Microsoft Academic Search

Resumo Este trabalho teve por objetivo o desenvolvimento de ímãs de ferrita a serem utilizados em sensor de velocidade para motor de arranque de um avião, fabricado pela empresa Aeromot de Canoas - RS. Dois tipos de ímãs foram solicitados pela empresa: na forma de cilindro e na forma de anel. Para a confecção dos ímãs, foi utilizada uma matéria-prima

Moisés de Mattos Dias; Lírio Schaeffer; Arão de Matos Dias; José Lesina Cezar; José Carlos; Krause de Verney

83

Para-hydrogen perspectives in hyperpolarized NMR  

NASA Astrophysics Data System (ADS)

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.

Glöggler, Stefan; Colell, Johannes; Appelt, Stephan

2013-10-01

84

¿Y PARA QUÉ ME VALE A MÍ LA HISTORIA?  

Microsoft Academic Search

La historia se sitúa como un instrumento idóneo para el desarrollo, no ya sólo de los conocidos como países poco desarrollados, sino también para los denominados desarrollados. Aparece como una herramienta de integración de conocimientos y que arma al ciudadano con destrezas propias y necesarias para su desarrollo personal, pero también para el desarrollo colectivo de la sociedad. Podemos usarla

Antonio Manuel Luna González

2009-01-01

85

The para radiation effects current simulator  

Microsoft Academic Search

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

Bharat Bhuva; Sherra Kerns

1992-01-01

86

The Impact of Family Support on the Success of Black Men at an Historically Black University: Affirming the Revision of Tinto’s Theory  

Microsoft Academic Search

: This qualitative study of 11 Black male students who entered a public historically Black college and university (HBCU) as academically underprepared and persisted to graduation, provides insight into the ways in which family promotes academic success for Black male students at a public HBCU. The study’s findings encourage practitioners at HBCUs to reassess the relationship between family involvement and

Dina C. Maramba; Robert T. Palmer; Ryan J. Davis

2011-01-01

87

The Impact of Family Support on the Success of Black Men at an Historically Black University: Affirming the Revision of Tinto’s Theory  

Microsoft Academic Search

This qualitative study of 11 Black male students who entered a public historically Black college and university (HBCU) as academically underprepared and persisted to graduation, provides insight into the ways in which family promotes academic success for Black male students at a public HBCU. The study’s findings encourage practitioners at HBCUs to reassess the relationship between family involvement and academic

Dina C. Maramba; Robert T. Palmer; Ryan J. Davis

2011-01-01

88

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

2013-07-24

89

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.

90

¿Qué es VAERS? El Sistema para Reportar Reacciones ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... www.vaers.hhs.gov Sistema Sistema para para Reportar Reportar Reacciones Reacciones Adversas Adversas aa las las Vacunas Vacunas ... More results from www.fda.gov/downloads/biologicsbloodvaccines/safetyavailability

91

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

92

Para-Bose oscillator as a deformed Bose oscillator  

NASA Astrophysics Data System (ADS)

We show that a single para-Bose oscillator may be regarded as a deformed Bose oscillator. We construct a nonlinear realization of the single-mode para-Bose algebra in terms of a single boson. This is in contrast to the Green decomposition that expresses a single para-Bose oscillator in terms of p anticommuting bosons. We also construct an operator canonically conjugate to the para-Bose annihilation operator that permits us to carry over familiar constructions to the para-Bosonic case.

Chaturvedi, S.; Srinivasan, V.

1991-12-01

93

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.

94

New strategies maximize para-xylene production  

SciTech Connect

Strong consumption growth and the shutdown of some capacity in 1992 have completely eliminated the surplus of para-xylene (p-xylene) capacity, which existed from 1990 to 1993. p-Xylene supplies are becoming tight and market prices have risen dramatically over the last several months, sparking considerable interest in new p-xylene production capacity. However, adding new capacity does not necessarily mean building new grassroots facilities. Additional capacity can be found'' by creative use of existing BTX (benzene, toluene and xylenes) resources. Options include: debottleneck existing units, reload with new catalysts, convert idle units to new services and diversify into new feedstocks. By making the most of existing facilities, producers can capitalize on the current upswing of the p-xylene market cycle. The paper describes this high demand chemical and how it is integrated with BTX complexes, then discusses short-, medium-, and long-term strategies for increased production.

Jeanneret, J.J.; Low, C.D.; Zukauskas, V. (UOP, Des Plaines, IL (United States))

1994-06-01

95

[A large para-renal PEComa].  

PubMed

We report the case of a 45-year-old man with a voluminous para-renal mass. The tumor was composed of epithelioid or spindle-shaped eosinophilic and clear cells with some atypia and an elevated mitotic count. The immunohistochemical study was positive for anti-HMB45 antibodies and anti-actin-antibodies and negative for epithelial markers and PS100 antibodies. The diagnosis of epithelioid AML (PEComa) was established. Two years later, recurrence was observed with a voluminous mass in the left upper quadrant of the abdomen, with high cellular density and the same immunohistochemical features. This tumor belongs to the PEComa and is not easy to diagnose clinically and morphologically. The immunohistochemical phenotype is characteristic. AML are usually benign but some epithelioid AMLS outcome can be unfavorable with metastatic dissemination. Criteria of malignancy are not clearly defined in the literature. This case shows that the mitotic count and the tumor size are probably important. PMID:15480264

Audard, Virginie; Dorel-Le Théo, Maryline; Trincard, Marie-Dominique; Charitanski, Didier; Selmas, Valérie Barn; Vieillefond, Annick

2004-06-01

96

Modelling Withdrawal and Persistence for Initial Teacher Training: Revising Tinto's Longitudinal Model of Departure  

ERIC Educational Resources Information Center

|This paper proposes a theoretical model to explain trainee withdrawal and persistence within higher education (HE) based initial teacher training (ITT). Within ITT, attrition and persistence are under-researched and under-theorised, thus providing the rationale for this study. Within HE more broadly, a number of models have been proposed, most…

Roberts, Deborah

2012-01-01

97

El Libro de la Escritura por Pinguino Tinto (The Writing Book, by Inky Penguin).  

ERIC Educational Resources Information Center

|Presented completely in Spanish and intended for elementary level students, this book offers 12 writing ideas and several suggestions on how students can make a book using their writing. Each writing idea is presented with a brief description (addressed to the student), several examples of student writing, and a blank page on which to write.…

Padgett, Ron

98

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

Microsoft Academic Search

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

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

2011-01-01

99

Geological record of an acidic environment driven by iron hydrochemistry: The Tinto River system  

Microsoft Academic Search

The existence of possible hematitic strata on the surface of Mars demands a search for terrestrial analogues formed in unusual environments. This will help us to recognize and interpret environmental and, perhaps, biological signatures preserved in Mars' hematites. Such an analogue would allow us to establish valid reference systems based on geomicrobial and biogeochemical signatures. Two different aspects place the

David C. Fernández-Remolar; Nuria Rodriguez; Felipe Gómez; Ricardo Amils

2003-01-01

100

Prontuário Eletrônico Para Pacientes De Hanseníase Via Web  

Microsoft Academic Search

Resumo - Este artigo apresenta a proposta de um Prontuário Eletrônico Via WEB para pacientes que sofrem de Hanseníase (PEPHANS), tendo como objetivo dar suporte à tomada de decisão pelos gestores da área da saúde envolvidos no controle e tratamento da doença. Com o PEPHANS evitar-se-à duplicidade de dados, permitindo o reaproveitamento do cadastro de pacientes, gerando alertas para auxiliar

Flávia de Queiroz Fadel; Andreia Malucelli; Laudelino Cordeiro Bastos

101

Narcotráfico, violencia y desigualdad: una hipótesis para el caso colombiano  

Microsoft Academic Search

El propósito del ensayo es analizar los factores que explican la violencia en Colombia; para ello, el autor, retoma elementos fundamentalmente en el neoinstitucionalismo, en el narcotráfico y en la desigualdad. González, después de explorara los tres elementos antes enunciados, plantea la hipótesis de que la desigualdad es, a su juicio, el factor que más se aproxima para interpretar la

Jorge Iván González

2001-01-01

102

La negociación, una competencia fundamental para el diálogo social  

Microsoft Academic Search

Este artículo plantea que una adecuada implementación del diálogo social requiere de actores competentes para negociar y construir consensos. Un marco legal adecuado y la buena disposición de los actores son condiciones necesarias pero no suficientes para un diálogo social efectivo. Es indispensable el desarrollo de habilidades y competencias, como la negociación, que lo hagan posible. Con base en diversas

María Clara Jaramillo Jaramillo

2011-01-01

103

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.

104

III. Presentación de Proceso para todos los Métodos de ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... No use las palabras “still” (estacionario), “agitating” (agitación), “hydorstatic” (hidrostático), "flame" (llama) en el nombre del esterilizador.Para ... More results from www.fda.gov/food/guidanceregulation/foodfacilityregistration

105

ParaDiS-FEM dislocation dynamics simulation code primer  

SciTech Connect

The ParaDiS code is developed to study bulk systems with periodic boundary conditions. When we try to perform discrete dislocation dynamics simulations for finite systems such as thin films or cylinders, the ParaDiS code must be extended. First, dislocations need to be contained inside the finite simulation box; Second, dislocations inside the finite box experience image stresses due to the free surfaces. We have developed in-house FEM subroutines to couple with the ParaDiS code to deal with free surface related issues in the dislocation dynamics simulations. This primer explains how the coupled code was developed, the main changes from the ParaDiS code, and the functions of the new FEM subroutines.

Tang, M; Hommes, G; Aubry, S; Arsenlis, A

2011-09-27

106

Medicamentos sin receta: ¿Cual es adecuado para usted?  

Center for Drug Evaluation (CDER)

... sin receta sellan la mayoría de los productos indicadores de manipulación indebida para ayudar a proteger contra la manipulación criminal de las ... More results from www.fda.gov/drugs/resourcesforyou

107

Revisión Previa a la Concesión de la Licencia para las ...  

Center for Biologics Evaluation and Research (CBER)

Text VersionPage 1. Revisión Previa a la Concesión de la Licencia para las Vacunas Preventivas DIAPOSITIVA 1 Esta presentación ... More results from www.fda.gov/downloads/biologicsbloodvaccines/internationalactivities

108

No mundo de hoje é importante estar ALERTA para proteger ...  

Center for Food Safety and Applied Nutrition (CFSAN)

Text Version... and Prevention (Centros para Controlo e Prevenção de Doenças dos EUA) US Department of Agriculture (Departamento de Agricultura dos EUA) More results from www.fda.gov/downloads/food/fooddefense

109

IV. Presentación de Proceso para Sistemas en Envasado ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... Asigne un de SID único para cada formulario de presentación de proceso, en el formato YY-MM-DD/SSS basado en la fecha en que presenta el ... More results from www.fda.gov/food/guidanceregulation/foodfacilityregistration

110

Hypervalent iodine mediated para-selective fluorination of anilides.  

PubMed

A metal-free method for the direct regioselective fluorination of anilides has been developed. In the presence of bis(tert-butylcarbonyloxy)iodobenzene (PhI(OPiv)(2)) and hydrogen fluoride-pyridine, the para-fluorination products of anilides were obtained in moderate to good yields. Because of its operational safety and the use of readily available reagents, this new procedure provides facile access to a variety of para-fluorinated anilides. PMID:23228030

Tian, Tian; Zhong, Wen-He; Meng, Shuai; Meng, Xiang-Bao; Li, Zhong-Jun

2012-12-18

111

ParaWeb: towards world-wide supercomputing  

Microsoft Academic Search

In this paper, we describe the design of a system, called ParaWeb, for utilizing Internet or intra-net computing resources in a seamless fashion. The goal is to allow users to execute serial programs on faster compute servers or parallel programs on a variety of possibly heterogeneous hosts. ParaWeb provides extensions to the Java programming environment (through a parallel class library)

Tim Brecht; Harjinder S. Sandhu; Meijuan Shan; Jimmy Talbot

1996-01-01

112

Ortho- and para-hydrogen in neutron thermalization  

SciTech Connect

The large difference in neutron scattering cross-section at low neutron energies between ortho- and para-hydrogen was recognized early on. In view of this difference (more than an order of magnitude), one might legitimately ask whether the ortho/para ratio has a significant effect on the neutron thermalization properties of a cold hydrogen moderator. Several experiments performed in the 60`s and early 70`s with a variety of source and (liquid hydrogen) moderator configurations attempted to investigate this. The results tend to show that the ortho/para ratio does indeed have an effect on the energy spectrum of the neutron beam produced. Unfortunately, the results are not always consistent with each other and much unknown territory remains to be explored. The problem has been approached from a computational standpoint, but these isolated efforts are far from having examined the ortho/para-hydrogen problem in neutron moderation in all its complexity. Because of space limitations, the authors cannot cover, even briefly, all the aspects of the ortho/para question here. This paper will summarize experiments meant to investigate the effect of the ortho/para ratio on the neutron energy spectrum produced by liquid hydrogen moderators.

Daemen, L.L.; Brun, T.O.

1998-09-01

113

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

Code of Federal Regulations, 2013 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...

2013-07-01

114

Hox and paraHox genes in bivalve molluscs.  

PubMed

In this study, we sought the presence and analysed the sequences of the Hox and ParaHox genes in bivalve molluscs. The clustered Hox genes play a central role in anterior-posterior axial patterning in bilaterian metazoa, whereas the ParaHox gene cluster is a paralogue (evolutionary sister) of the Hox cluster. Using polymerase chain reaction (PCR)-based approaches, we isolated nine different sequences in five species belonging to three of the main bivalve subclasses: Ensis ensis and Tapes philippinarum (Heterodonta), Pecten maximus and Mytilus galloprovincialis (Pteriomorphia), and Yoldia eightsi (Protobranchia). Comparison with the Hox and ParaHox genes of other bilaterians, particularly lophotrochozoans, allowed us to attribute six of these sequences to the Hox gene cluster (one to paralog group [PG] 3 class, and five to the central class), two to the ParaHox cluster and one to the Gbx gene family. The results of our investigation seem to indicate that homeotic Hox and ParaHox gene clusters are homogeneous for both presence and characteristics in molluscs. PMID:14604796

Barucca, Marco; Olmo, Ettore; Canapa, Adriana

2003-10-23

115

[Erythema multiforme-like reaction to para-phenylenediamine].  

PubMed

A case of a 15 year-old girl who developed an erythema multiforme-like reaction to para-phenylenediamine (PPD) after Henna tattoos is described. The patient was treated successfully with oral prednisolone and highly potent topical corticosteroids. The patient developed a long-lasting post-inflammatory hyperpigmentation. Potential hyperreactive response was prevented by applying the PPD patch for only 30 minutes, but still there was a significantly positive reaction. This case highlights the need to ban the use of para-phenylenediamine and its derivates in dyes. PMID:21199625

Mikkelsen, Carsten Sauer; Liljefred, Frederik; Mikkelsen, Dorthe Bisgaard

2011-01-01

116

Plasma\\/blood pharmacokinetics and metabolism after dermal exposure to para-aminophenol or para-phenylenediamine  

Microsoft Academic Search

The pharmacokinetics and metabolism following dermal application of [14C]-para-aminophenol (PAP) or [14C]-para-phenylenediamine (PPD) were investigated. Groups of rats were treated under occlusion for 24h with 12.5mg\\/kg [14C]-PAP, or for 4h with 50mg\\/kg [14C]-PPD on 10% or 20% of their body surface area, respectively. A female minipig was also treated dermally (24h, occlusion) with 4.7mg\\/kg [14C]-PAP on 10% of its body

William E. Dressler; Terence Appelqvist

2006-01-01

117

Computational study of substituent effect in para substituted platinabenzene complexes  

NASA Astrophysics Data System (ADS)

The electronic structure and properties of the platinabenzene and para substituted platinabenzenes have been investigated using the hybrid density functional mpw1pw91 theory. The substituent effect in structure parameters, frontier orbital energies, aromaticity indexes, and hyperpolarizability has been studied. The calculations show that, in all molecules HOMO ? LUMO transition makes the major contribution in the most intense electronic transition.

Ghiasi, Reza; Pasdar, Hoda

2013-06-01

118

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

119

On the microscopic interaction of para-chlorofluorobenzene with water  

NASA Astrophysics Data System (ADS)

The isolated (1:1) complex of para-chlorofluorobenzene with water has been investigated by IR/R2PI depletion spectroscopy and ab initio calculations on the geometry and IR spectra. Whereas three different isomers (?F, ?Cl, ?) were located by theory, in the molecular beam experiments only the two ? isomers have been observed.

Riehn, C.; Reimann, B.; Buchhold, K.; Vaupel, S.; Barth, H.-D.; Brutschy, B.; Tarakashwar, P.; Kim, Kwang S.

2001-12-01

120

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

121

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

122

Zur Behandlung der Keratitis dendritica mit para-Fluorphenylalanin  

Microsoft Academic Search

An 53 in der Mehrzahl ambulant behandelten Patienten mit einer Keratitis dendritica wurde der therapeutische Effekt von para-Fluorphenylalanin (pFPA) und von 5-Jod-2-deoxyuridin (IDU) in Form einer 0,1 % igen Salbe vergleichend untersucht. Beide Präparate erwiesen sich als gleichermaßen gut wirksam.

K. Graupner; F. Müller

1968-01-01

123

Analyzing and Visualizing Cosmological Simulations with ParaView  

NASA Astrophysics Data System (ADS)

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; Heitmann, Katrin; Ahrens, James; Fasel, Patricia; Hsu, Chung-Hsing; Habib, Salman; Pope, Adrian

2011-07-01

124

Implantable direct current stimulation in para-axial cervical arthrodesis  

Microsoft Academic Search

This retrospective, case-controlled pilot study was designed to examine the efficacy and safety of an implantable direct current\\u000a bone growth stimulator (IDCBGS) as an adjunct to cervical arthrodesis in patients at high risk for nonunion after undergoing\\u000a cervical fusion in region from the occiput to C3. Twenty patients underwent para-axial cervical arthrodesis (involving posterior\\u000a spine fusion and instrumentation using standard

William C. Welch; Shari L. Willis; Peter C. Gerszten

2004-01-01

125

Decreased production of para -hydroxypenicillin V in penicillin V fermentations  

Microsoft Academic Search

Summary Penicillin V (phenoxymethyl penicillin) is produced by industrial strains ofPenicillium chrysogenum in the presence of phenoxyacetic acid (POAc), a side-chain precursor for the penicillin V molecule. The wild-type strain ofP. chrysogenum produces an undesirable penicillin byproduct,para-hydroxypenicillin V (p-OH penicillin V), in addition to penicillin V, viapara-hydroxylation of POAc and subsequent incorporation of thep-OH phenoxyacetic acid into the penicillin molecule.

L. T. Chang; E. L. McGrory; R. P. Elander; D. J. Hook

1991-01-01

126

Colorimetric Analysis of the Acrosin Inhibitor Para-Aminobenzamidine  

Microsoft Academic Search

A method is presented for the colorimetric assay of para-aminobenzamidine (PAB) in blood. Essentially, the PAB in trichloroacetic acid extracts is coupled to N-(l-napthyl)ethylenediamine in a typical diazotization reaction. The colored complex formed exhibits a peak absorption at 540 nm. This complex in distilled water is very stable and loses less than 5% of its absorptivity over a 24 hour

L. L. Rolf Jr; D. F. Hudgins

1979-01-01

127

Process for para selective alkylation of aromatic hydrocarbons  

SciTech Connect

A process is described for the selective alkylation of monoalkylbenzene into dialkylbenzenes wherein the para isomer of the disubstituted product is present in a concentration greater than in an thermodynamic equilibrium, comprising: passing the monoalkylbenzene and an alkylating agent capable of methylation, ethylation or propylation under conversion conditions through a reaction zone containing an unmodified crystalline silica catalyst of the silicalite type having the monoclinic symmetry.

Debras, G.L.G.; DeClippeleir, G.E.M.J.; Cahen, R.M.

1986-07-08

128

Paraphrasing invariance coefficient: measuring para-query invariance of search engines  

Microsoft Academic Search

Paraphrasing is the restatement (or reuse) of text which preserves its meaning in another form. A para-query is a para-phrase of a search query. Humans easily recognize para-queries, but search engines are still far away from it. We claim that in order for a search engine to be called semantic it is necessary that it recognizes para-queries by returning the

Tomasz Imielinski; Jinyun Yan; Yihan Fang; Kurt Eldridge; Huiwen Yu; Peter Kelly

2010-01-01

129

Herramientas de simulación de código abierto para l a mejora del aprendizaje en Ingeniería Eléctrica  

Microsoft Academic Search

Este artículo describe una iniciativa para el uso d e herramientas de simulación como un procedimiento para mejorar el aprendizaje en los es tudios de ingeniería, concretamente en la asignatura de máquinas eléctricas. Estos métodos pe rmiten que los estudiantes mejoren la comprensión de los fenómenos físicos subyacentes y sus habilidades para resolver problemas con unos

A. Domínguez; M. Yusta

130

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

Microsoft Academic Search

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.

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

2006-01-01

131

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

132

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

133

IL CONTRIBUTO DELL'ANALISI SPAZIALE DI SUPERFICIE A SUPPORTO DELLA RETE MOBILE DI PRONTO INTERVENTO DEL CENTRO NAZIONALE TERREMOTI (INGV)  

Microsoft Academic Search

The emergency mobile seismic network (RPI) is a structure that belongs to the Centro Nazionale Terremoti (INGV), and allows, in case of seismic event, to increase the number of seismic stations in the epicentral area. The peculiarity of this structure is the possibility to transmit the data flow in real-time to the acquisition center. The RPI is constituted by nine

Raffaele MOSCHILLO; Maurizio PIGNONE; Luigi ABRUZZESE; Marco CATTANEO

134

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

135

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

136

Tautomeric equilibria of para-bromophenyl substituted arylhydrazones of ?-diketones  

Microsoft Academic Search

New arylhydrazone derivatives of ?-diketones, 2-(4-bromophenylhydrazono)-5,5-dimethylcyclohexane-1,3-dione (1), 5-(4-bromophenylhydrazono)pyrimidine-2,4,6(1H,3H,5H)-trione (2) and (E)-2-(4-bromophenylhydrazono)-1-phenylbutane-1,3-dione (3), were prepared by coupling of ?-diketone with the respective para-bromophenyldiazonium chloride, and characterized by IR, 1H and 13C NMR spectra. The IR and NMR spectral data disclose an effective intramolecular hydrogen bonding in all the cases. The single crystal X-ray analysis of 3-(4-bromophenyl-hydrazono)pentane-2,4-dione (4) evidences the intramolecular resonance-assisted

Kamran T. Mahmudov; Abel M. Maharramov; Rafiga A. Aliyeva; Famil M. Chyragov; Rizvan K. Askerov; Parvin Q. Hasanov; Maximilian N. Kopylovich; Armando J. L. Pombeiro

137

Pneumatic protection applied to an airbag for para-gliders  

NASA Astrophysics Data System (ADS)

We present a theory of pneumatic protection based on the laws of thermodynamics, elasticity and fluid mechanics. A general pneumatic protection system is made up of several communicating compartments, the differences in pressure of the compartments generating a transfer of mass and energy between them. The transfer offers interesting possibilities to improve the performance of the system. An example of this type of protection in aerial sport is the airbag for para-gliders, it is used in this paper to illustrate the theory. As the pressure in the airbag depends uniquely on its volume, the geometric model in the theory can be simplified. Experiments carried out with crash-test dummies equipped with sensors have confirmed the theoretical predictions.

Raievski, V.; Valladas, G.

1998-02-01

138

Para-Sexiphenyl Layers Grown On Light Sensitive Polymer Substrates  

NASA Astrophysics Data System (ADS)

In this contribution the deposition of Para-sexiphenyl (PSP) layers on poly (diphenyl bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate) (PPNB) by Hot Wall Epitaxy (HWE) is reported. It is demonstrated that pre-treating the substrate by UV-illumination induces a clear change in the morphology of the grown PSP films due to the polarity modification of the substrate surface. PPNB surface polarity increases when illuminated by UV via photo-Fries rearrangement. By detailed atomic force microscopy analysis the influence on the growth kinetics by the substrate temperature, deposition time and particularly by the UVtreatment of the substrate was investigated. A high crystalline order of the films is underlined by the observation of growth spirals and terraced islands, providing mono-layer step heights of standing PSP-molecules.

Hernandez-Sosa, G.; Simbrunner, C.; Höfler, T.; Moser, A.; Werzer, O.; Kunert, B.; Trimmel, G.; Kern, W.; Resel, R.; Sitter, H.

139

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

140

Estimación de las funciones de costo marginal de abatimiento de material particulado para fuentes fijas en el Valle de Aburrá  

Microsoft Academic Search

Este artículo tiene como objetivo principal estimar las funciones de costo marginal de abatimiento de material particulado para fuentes fijas en el Valle de Aburrá. Esta información es necesaria si se desea establecer in Sistema de Permisos de Emisión Tranasables para el área Metropolitana, como política ambiental para el control de contaminación atmosférica por material particulado. Para la estimulación de

Milena Eveyde Mejía Giraldo; Iván David Oviedo Restrepo

2006-01-01

141

Under the skin: Biotransformation of para-aminophenol and para-phenylenediamine in reconstructed human epidermis and human hepatocytes.  

PubMed

We investigated the biotransformation of the oxidative arylamine (AA) hair dye ingredients [14C]-para-aminophenol (PAP) and [14C]-para-phenylenediamine (PPD) in reconstructed human epidermis and human hepatocytes. Human epidermis quantitatively transformed PAP to its N-acetylated derivative (APAP), whereas hepatocytes transformed PAP to sulfate or glucuronic acid conjugates of APAP or PAP as well as free APAP. Epidermis and hepatocytes converted PPD to N-mono- (MAPPD) and N,N'-di-acetylated (DAPPD) derivatives. At higher concentrations of PPD (250-1000 microM), epidermis or hepatocytes produced more of the MAPPD, whereas concentrations below 250 microM and lower favoured formation of the DAPPD metabolite. When compared with epidermis, human hepatocytes had a three-fold or eight-fold greater capacity for generation of MAPPD or DAPPD, respectively. No evidence of transformation of PAP or PPD to N-hydroxylated derivatives was found in epidermis or hepatocytes. Our results suggest that (i) after dermal absorption of PAP or PPD, humans are systemically exposed to acetylated derivatives; (ii) current in vitro skin absorption studies may be inadapated for determination of human systemic exposure to AAs due to reduced or absent metabolic capacity of non-viable skin; (iii) due to qualitative differences between dermal and hepatic metabolism, oral toxicity studies may be unsuited for the hazard assessment of dermal exposure to AAs; and (iv) use of induced rodent liver S9 metabolic activation systems for in vitro genotoxicity studies may produce misleading results on the hazard of human dermal exposure to AAs. In conclusion, our data support the growing evidence that AAs are transformed in human skin and suggest that current practices of safety assessment of AAs should take these findings into account. PMID:15890478

Nohynek, Gerhard J; Duche, Daniel; Garrigues, Alexia; Meunier, Pierre-Alain; Toutain, Herve; Leclaire, Jacques

2005-09-15

142

ParaTimer: a progress indicator for MapReduce DAGs  

Microsoft Academic Search

Time-oriented progress estimation for parallel queries is a challenging problem that has received only limited attention. In this paper, we present ParaTimer, a new type of time-remaining indicator for parallel queries. Several parallel data processing systems exist. ParaTimer targets environments where declarative queries are translated into ensembles of MapReduce jobs. ParaTimer builds on previous techniques and makes two key contributions.

Kristi Morton; Magdalena Balazinska; Dan Grossman

2010-01-01

143

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

Microsoft Academic Search

A method 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

Frances H. Arnold; Jeffrey C. Moore

1999-01-01

144

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

Microsoft Academic Search

A method 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

Frances H. Arnold; Jeffrey C. Moore

1998-01-01

145

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

Microsoft Academic Search

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

F. H. Arnold; J. C. Moore

1998-01-01

146

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

Microsoft Academic Search

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

F. H. Arnold; J. C. Moore

1999-01-01

147

Use of UV ParaLens Adapter for Detection of Acid-Fast Organisms  

Microsoft Academic Search

Auramine-stained mycobacterial smears from 136 clinical specimens were interpreted by using the UV ParaLens adapter (Beckton Dickinson), and results were compared with smear interpretations using a traditionalfluorescentmicroscopeandculture.ThesensitivityandspecificityoftheParaLenswere84and93%, respectively. Smears yielding discrepant results were overstained by the Kinyoun method. Overall, the sensitivity of auramine-stained smears interpreted with the UV ParaLens was comparable to that of Kinyoun-stained smears. The recent increase in

KIMBERLEY V. PATTERSON; CLIFFORD L. MCDONALD; BRENDA F. MILLER; ANDKIMBERLE C. CHAPIN

148

Glycine conjugation of para-aminobenzoic acid (PABA): A quantitative test of liver function  

Microsoft Academic Search

To evaluate glycine conjugation of para-aminobenzoic acid (PABA) to the hippurated metabolites, para-aminohippuric acid (PAHA), and para-acetamidohippuric acid (PAAHA) as a quantitative liver function test in patients with liver disease.Serum concentrations of PABA and metabolites were measured by high pressure liquid chromatography in 24 controls and 50 patients with hepatobiliary disease.Hippurate formation was significantly decreased in all patient groups with

Katryn N. Furuya; Peter R. Durie; Eve A. Roberts; Steven J. Soldin; Zul Verjee; Linda Yung-Jato; Esther Giesbrecht; Lynda Ellis

1995-01-01

149

Ortho–Para Mixing Hyperfine Interaction in the H2O+ Ion and Nuclear Spin Equilibration  

NASA Astrophysics Data System (ADS)

The ortho to para conversion of water ion, H2O+, due to the interaction between the magnetic moments of the unpaired electron and protons has been theoretically studied to calculate the spontaneous emission lifetime between the ortho- and para-levels. The electron spin-nuclear spin interaction term, Tab(Sa-Ib + Sb-Ia) mixes ortho (I = 1) and para (I = 0) levels to cause the -forbidden- ortho to para |-I| = 1 transition. The mixing term with Tab = 72.0 MHz is 4 orders of magnitude higher for H2O+ than for its neutral counterpart H2O where the magnetic field interacting with proton spins is by molecular rotation rather than the free electron. The resultant 108 increase of ortho to para conversion rate possibly makes the effect of conversion in H2O+ measurable in laboratories and possibly explains the anomalous ortho to para ratio recently reported by Herschel heterodyne instrument for the far-infrared (HIFI) observation. Results of our calculations show that the ortho - para mixings involving near-degenerate ortho and para levels are high (-10-3), but they tend to occur at high energy levels, -300 K. Because of the rapid spontaneous emission, such high levels are not populated in diffuse clouds unless the radiative temperature of the environment is very high. The low-lying 101 (para) and 111 (ortho) levels of H2O+ are mixed by -10-4 making the spontaneous emission lifetime for the para 101 - ortho 000 transition 520 years and 5200 years depending on the F value of the hyperfine structure. Thus the ortho - para conversion due to the unpaired electron is not likely to seriously affect thermalization of interstellar H2O+ unless either the radiative temperature is very high or number density of the cloud is very low.

Tanaka, Keiichi; Harada, Kensuke; Oka, Takeshi

2013-10-01

150

Ortho-Para Mixing Hyperfine Interaction in the H2O(+) Ion and Nuclear Spin Equilibration.  

PubMed

The ortho to para conversion of water ion, H2O(+), due to the interaction between the magnetic moments of the unpaired electron and protons has been theoretically studied to calculate the spontaneous emission lifetime between the ortho- and para-levels. The electron spin-nuclear spin interaction term, Tab(Sa?Ib + Sb?Ia) mixes ortho (I = 1) and para (I = 0) levels to cause the "forbidden" ortho to para |?I| = 1 transition. The mixing term with Tab = 72.0 MHz is 4 orders of magnitude higher for H2O(+) than for its neutral counterpart H2O where the magnetic field interacting with proton spins is by molecular rotation rather than the free electron. The resultant 10(8) increase of ortho to para conversion rate possibly makes the effect of conversion in H2O(+) measurable in laboratories and possibly explains the anomalous ortho to para ratio recently reported by Herschel heterodyne instrument for the far-infrared (HIFI) observation. Results of our calculations show that the ortho ? para mixings involving near-degenerate ortho and para levels are high (?10(-3)), but they tend to occur at high energy levels, ?300 K. Because of the rapid spontaneous emission, such high levels are not populated in diffuse clouds unless the radiative temperature of the environment is very high. The low-lying 101 (para) and 111 (ortho) levels of H2O(+) are mixed by ?10(-4) making the spontaneous emission lifetime for the para 101 ? ortho 000 transition 520 years and 5200 years depending on the F value of the hyperfine structure. Thus the ortho ? para conversion due to the unpaired electron is not likely to seriously affect thermalization of interstellar H2O(+) unless either the radiative temperature is very high or number density of the cloud is very low. PMID:23530629

Tanaka, Keiichi; Harada, Kensuke; Oka, Takeshi

2013-04-25

151

LA RAZA COMO DETERMINANTE DEL ACCESO A UN EMPLEO DE CALIDAD: UN ESTUDIO PARA CALI  

Microsoft Academic Search

La discriminación laboral por raza ha sido un tema ampliamente analizado en la economía del trabajo a partir de la estimación de ecuaciones de ingreso para determinar diferenciales en el salario, pero la influencia de este factor en el acceso a un empleo de calidad no se ha explorado lo suficiente. Realizar este análisis cobra vital importancia para una ciudad

CHRISTIAN DAVID BUSTAMANTE; SANTIAGO ARROYO

2008-01-01

152

Escolha de locais para instalação de torres de detecção de incêndio com auxílio do SIG  

Microsoft Academic Search

RESUMO - O objetivo deste trabalho foi realizar um teste metodológico para avaliar as potencialidad es de um sistema de informações geográficas e suas rotinas no planejamento de distribuição de torres de incêndio e na determinação do número ótimo de torres para visualização de uma área de estudo. A área estudada foi de 441,81 ha, em Belo Oriente-MG, compreendendo povoamentos

Gilciano Saraiva Nogueira; Guido Assunção Ribeiro; Carlos Antonio Alvares Soares Ribeiro; Evandro Pereira Silva

2002-01-01

153

Modeling and control system design of an industrial crystallizer train for para-xylene recovery  

Microsoft Academic Search

A dynamic process model of an industrial crystallizer train for para-xylene production, which consists of five scraped surface crystallizers, two hydrocyclone separators, and two centrifugal separators, is developed for control system design, and the model parameters are estimated from real plant data. Based on the identified model, steady state optimal operation policy, which considers maximization of para-xylene recovery and load

Hiroya Seki; Souichi Amano; Genichi Emoto

2010-01-01

154

Un índice de carencias en la niñez. Una aproximación por Dpartamentos para Colombia  

Microsoft Academic Search

RESUMEN En este trabajo se construye un indicador sintético, denominado Índice de Carencias para la Niñez Colombiana (ICNC). El ICNC resume el acceso a un conjunto de bienes y servicios en áreas clave para el bienestar y cumplimiento de los derechos del niño. En particular, las carencias que mide el ICNC tienen el objeto de dar a conocer si los

Luis Fernando Aguado Quintero; Ana María Osorio Mejía; Carlos Alberto García González

2009-01-01

155

La Liga de Alumnos Amigos: Desarrollo de las habilidades sociales del alumnado para prestar apoyo socioemocional  

Microsoft Academic Search

Resumen: Integrado en el proyecto subvencionado por la Unión Europea Training and Mobility for Researchers para el estudio y la prevención de los malos tratos entre iguales y por el Proyecto Sócrates Comenius I, se desa- rrolla el Programa de Educación para la Convivencia en Contextos Educativos (EC- CE) destinado a combatir y prevenir el maltrato entre iguales. Una de

Juan Luís Benítez Muñoz; Ana María Tomás de Almeida; Fernando Justicia Justicia

2007-01-01

156

Experiences Using the ParaScope Editor: an Interactive Parallel Programming Tool  

Microsoft Academic Search

The ParaScope Editor is an interactive parallel pro- gramming tool that assists knowledgeable users in de- veloping scientific Fortran programs. It displays the re- sults of sophisticated program analyses, provides a set of powerful interactive transformations, and supports program editing. This paper summarizes experiences of scientific programmers and tool designers using the ParaScope Editor. We evaluate existing features and describe

Mary W. Hall; Timothy J. Harvey; Ken Kennedy; Nathaniel McIntosh; Kathryn S. McKinley; Jeffrey D. Oldham; Michael H. Paleczny; Gerald Roth

1993-01-01

157

Experiences using the ParaScope Editor: an interactive parallel programming tool  

Microsoft Academic Search

The ParaScope Editor is an interactive parallel programming tool that assists knowledgeable users in developing scientific Fortran programs. It displays the results of sophisticated program analyses, provides a set of powerful interactive transformations, and supports program editing. This paper summarizes experiences of scientific programmers and tool designers using the ParaScope Editor. We evaluate existing features and describe enhancements in three

Mary W. Hallt; Timothy J. Harvey; Ken Kennedy; Nathaniel McIntosh; Kathryn S. McKinley; Jeffrey D. Oldham; Michael H. Paleczny; Gerald Roth

1993-01-01

158

COD, para-chlorophenol and toxicity removal from para-chlorophenol containing synthetic wastewater in an activated sludge unit.  

PubMed

Chlorinated phenolic compounds present in some chemical industry wastewaters cause severe toxic effects on the organisms and often are resistant to biological degradation. Synthetic wastewater containing different concentrations of para-chlorophenol (4-chlorophenol, 4-CP) was biologically treated in an activated sludge unit for COD, 4-CP and toxicity removal. Effects of feed 4-CP concentration on COD, 4-CP, toxicity removals and on sludge volume index were investigated at a constant sludge age of 20 days and hydraulic residence time (HRT) of 25 h. Resazurin method based on dehydrogenase activity was used for determination of the toxicity of the feed and effluent wastewater. COD and 4-CP removals were not affected by the presence of 4-CP in the wastewater up to feed 4-CP concentration of 925 mg l(-1) because of almost complete degradation of 4-CP yielding lower than 50 mg l(-1) 4-CP in the aeration tank. Percent COD, 4-CP and toxicity removals decreased and the effluent COD, 4-CP and toxicity levels increased with further increases in the feed 4-CP concentrations above 925 mg l(-1) because of inhibitory concentrations of 4-CP in the reactor. Biomass concentration in the aeration tank decreased and the sludge volume index (SVI) increased with feed 4-CP concentrations above 925 mg l(-1) resulting in lower COD and 4-CP removal rates. The rates of COD and 4-CP removals indicated substrate (4-CP) inhibition for the feed 4-CP concentrations above 925 mg l(-1) corresponding to the reactor 4-CP of above 200 mg l(-1). The system should be operated at the feed 4-CP concentrations of less than 900 mg l(-1) (4-CP(R) < 200 mg l(-1)) in order to obtain high rates and extents of COD, 4-CP and toxicity removals at a sludge age of 20 days and HRT of 25 h. PMID:16257114

Kargi, Fikret; Konya, Isil

2005-10-27

159

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

DOEpatents

A method 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.

Arnold, Frances H. (Pasadena, CA); Moore, Jeffrey C. (Pasadena, CA)

1998-01-01

160

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

DOEpatents

A method 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.

Arnold, Frances H. (Pasadena, CA); Moore, Jeffrey C. (Pasadena, CA)

1999-01-01

161

Modelos Teoricos de Linhas de Recombinacao EM Radio Frequencias Para Regioes H II  

NASA Astrophysics Data System (ADS)

Foram feitos modelos de linhas de recombinção provenientes de regiões HII nas frequências de rádio para distintos números quãnticos. Estes modelos consideram regrões H II esfericamente simétricas com variações radiais na densidade e temperatura eletrônica, efeitos de colisoes inelásticas dos eletrons (alargarnento por pressão), e afastarnento do equiliíbrio termodinâmico local. 0 bojetivo é construir o perfil da linha para cada ponto da nuvern e obter o valor médio resultante da sua convoluçã com o feixe da antena de tarnanho comparável corn o tarnanho angular da nuvern para posterIor cornpara o corn

Abraham, Z.; Cancoro, A. C. O.

1987-05-01

162

Aplicación del Teorema de Nekhorochev para tiempos de estabilidad en Mecánica Celeste  

NASA Astrophysics Data System (ADS)

En Mecánica Celeste, uno de los problemas centrales consiste en la determinación de los tiempos de estabilidad. El teorema de Nekhorochev proporciona un método para dicho estudio, para un sistema determinado por un hamiltoniano descripto en las variables acción-ángulo. El trabajo consiste en la acotación tanto del potencial perturbador y de la matriz hessiana del hamiltoniano integrable para determinar luego el tiempo de estabilidad de dicho sistema, donde por estabilidad se entiende la separación en norma infinito en el espacio de las acciones.

Miloni, O.; Núñez, J.; Brunini, A.

163

Binary recombination of para- and ortho-H3+ with electrons at low temperatures.  

PubMed

Results of an experimental study of binary recombination of para- and ortho-H(3)(+) ions with electrons are presented. Near-infrared cavity-ring-down absorption spectroscopy was used to probe the lowest rotational states of H(3)(+) ions in the temperature range of 77-200?K in an H(3)(+)-dominated afterglow plasma. By changing the para/ortho abundance ratio, we were able to obtain the binary recombination rate coefficients for pure and para-H(3)(+) and ortho-H(3)(+). The results are in good agreement with previous theoretical predictions. PMID:23028157

Dohnal, P; Hejduk, M; Varju, J; Rubovic, P; Roucka, S; Kotrík, T; Plasil, R; Johnsen, R; Glosík, J

2012-11-13

164

All the three ParaHox genes are present in Nuttallochiton mirandus (Mollusca: polyplacophora): evolutionary considerations.  

PubMed

The ParaHox gene cluster contains three homeobox genes, Gsx, Xlox and Cdx and has been demonstrated to be an evolutionary sister of the Hox gene cluster. Among deuterostomes the three genes are found in the majority of taxa, whereas among protostomes they have so far been isolated only in the phylum Sipuncula. We report the partial sequences of all three ParaHox genes in the polyplacophoran Nuttallochiton mirandus, the first species of the phylum Mollusca where all ParaHox genes have been isolated. This finding has phylogenetic implications for the phylum Mollusca and for its relationships with the other lophotrochozoan taxa. PMID:16331637

Barucca, Marco; Biscotti, Maria A; Olmo, Ettore; Canapa, Adriana

2006-03-15

165

ParaBIT-1: 60Gb\\/s-throughput parallel optical interconnect module  

Microsoft Academic Search

We previously proposed ParaBIT (parallel inter-board optical interconnection technology), and developed a prototype front-end module, called ParaBIT-0, with a total throughput of 28 Gb\\/s (700 Mb\\/s×40 ch). Aiming at higher throughput, lower cost, and further miniaturization, we are now developing a version, called ParaBIT-1, which is designed to achieve a total throughput of 60 Gb\\/s (1.25 Gbit\\/s×480-ch). To achieve a

Mitsuo Usui; Nobuo Sato; Akira Ohki; Nobuaki Matsuura; Nobuyuki Tanaka; Koji Enbutsu; Michiyuki Amano; Makoto Hikita; Toshiaki Kagawa; Kohsuke Katsura; Yasuhiro Ando

2000-01-01

166

Simultaneous Determination of Inulin and Para-Aminohippuric Acid in Plasma and Urine by an Automated Technique.  

National Technical Information Service (NTIS)

An automated technique is described for the simultaneous determination of inulin and para-aminohippuric acid in plasma and urine. Inulin is determined by the indolylacetic acid reaction in the presence of concentrated hydrochloric acid. Para-aminohippuric...

P. Z. Sobocinski

1972-01-01

167

MÉTODO SIMPLE PARA LA DETECCIÓN MÚLTIPLE DE VIROIDES DE CÍTRICOS A SIMPLE METHOD FOR THE MULTIPLE DETECTION OF CITRUS VIROIDS  

Microsoft Academic Search

La detección de viroides mediante RT-PCR en México es de uso común en los laboratorios de acreditación para determinar la calidad sanitaria de plantas de cítricos, cuando se van a utilizar árboles madre para propagar plantas de vivero. En el presente trabajo se describe una metodología simple para la detección múltiple de los viroides Citrus exocortis viroid (CEVd), CVd II,

Isidro H. Almeyda-León; Mario A. Rocha-Peña; M. Magdalena Iracheta-Cárdenas; Fermín Orona-Castro; Craig J. Kahlke

168

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…

Raval, Harini; McKenney, Susan; Pieters, Jules

2012-01-01

169

Para-Hydroxybenzoate as an Intermediate in the Anaerobic Transformation of Phenol to Benzoate.  

National Technical Information Service (NTIS)

Anaerobic phenol transformation was studied using a consortium which transformed phenol to benzoate without complete mineralization of benzoate. Products of monofluorophenol transformation indicated para-carboxylation. Phenol and benzoate were detected du...

B. R. Sharak Genthner G. T. Townsend P. J. Chapman

1991-01-01

170

Elementos para una reforma del sector público en el contexto de una economía de mercado  

Microsoft Academic Search

En este trabajo se propone un conjunto de elementos básicos que deben ser considerados para el diseño de cualquier estrategia de reforma del sector público en el Perú, abordando cuestiones de carácter económico, social, político y de organización institucional.

Claudio Herzka

1996-01-01

171

Communications: Development and characterization of a source of rotationally cold, enriched para-H3+  

NASA Astrophysics Data System (ADS)

In an effort to develop a source of H3+ that is almost entirely in a single quantum state (J=K=1), we have successfully generated a plasma that is enriched to ~83% in para-H3+ at a rotational temperature of 80 K. This enrichment is a result of the nuclear spin selection rules at work in hydrogenic plasmas, which dictate that only para-H3+ will form from para-H2, and that para-H3+ can be converted to ortho-H3+ by subsequent reaction with H2. This is the first experimental study in which the H2 and H3+ nuclear spin selection rules have been observed at cold temperatures. The ions were produced from a pulsed solenoid valve source, cooled by supersonic expansion, and interrogated via continuous-wave cavity ringdown spectroscopy.

Tom, Brian A.; Mills, Andrew A.; Wiczer, Michael B.; Crabtree, Kyle N.; McCall, Benjamin J.

2010-02-01

172

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

173

ParaHox gene expression in the polychaete annelid Capitella sp. I  

Microsoft Academic Search

Hox and ParaHox genes are transcriptional regulators vital for many aspects of embryonic development in bilaterian animals and are considered\\u000a to have originated from one ancestral proto-Hox\\/ParaHox cluster. Hox genes are clustered in the genome of both protostomes and deuterostomes, and there is a specific relationship between the\\u000a position of a gene in the cluster and the position of its

Andreas C. Fröbius; Elaine C. Seaver

2006-01-01

174

Laparoscopic Para-aortic and Pelvic Lymphadenectomy: Experience with 150 Patients and Review of the Literature  

Microsoft Academic Search

Objective.The clinical usefulness of laparoscopic pelvic and para-aortic lymphadenectomy for staging and therapy of gynecological cancer was analyzed prospectively.Method.Laparoscopic para-aortic and pelvic lymphadenectomy was performed in 150 patients with cervical (n= 96), endometrial (n= 41), or ovarian cancer (n= 13). Lymphadenectomy was combined with laparoscopically assisted vaginal radical hysterectomy in 70 patients, with laparoscopically assisted vaginal hysterectomy and\\/or bilateral salpingo-oophorectomy

Marc Possover; Norman Krause; Karin Plaul; Rosemarie Kühne-Heid; Achim Schneider

1998-01-01

175

The ParaPhrase Project: Parallel Patterns for Adaptive Heterogeneous Multicore Systems  

Microsoft Academic Search

This paper describes the ParaPhrase project, a new 3-year targeted research project funded under EU Framework 7 Objective 3.4 (Computer Systems), starting in October 2011. ParaPhrase aims to follow a new approach to introducing parallelism using advanced refactoring techniques coupled with high-level parallel design patterns. The refactoring approach will use these design patterns to restructure pro- grams defined as networks

Kevin Hammond; Marco Aldinucci; Chris Brown; Francesco Cesarini; Marco Danelutto; Horacio Gonz'alez-V'elez; Peter Kilpatrick; Rainer Keller; Michael Rossbory; Gilad Shainer

2013-01-01

176

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

177

Definição de um Ambiente para apoiar a Gerência de Conhecimento para Projeto de Banco de Dados utilizando um Framework Conceitual e Padrões de Análise  

Microsoft Academic Search

Resumo Uma das grandes dificuldades no desenvolvimento de software é que, muitas vezes, os desenvolvedores não estão familiarizados com o domínio para o qual o software está sendo desenvolvido. A necessidade de apoiar o desenvolvimento de software em domínio específicos tem sido endereçada tanto por Ambientes de Desenvolvimento de Software Orientados a Domínio (ADSODs), como pelo uso de gerência do

Viviane C. Dias; Carlos A. M. Pietrobon; Mário Fabiano Alves

178

Vínculos observacionais para o processo-S em estrelas gigantes de Bário  

NASA Astrophysics Data System (ADS)

Estrelas de bário são gigantes vermelhas de tipo GK que apresentam excessos atmosféricos dos elementos do processo-s. Tais excessos são esperados em estrelas na fase de pulsos térmicos do AGB (TP-AGB). As estrelas de bário são, no entanto, menos massivas e menos luminosas que as estrelas do AGB, assim, não poderiam ter se auto-enriquecido. Seu enriquecimento teria origem em uma estrela companheira, inicialmente mais massiva, que evolui pelo TP-AGB, se auto-enriquece com os elementos do processo-s e transfere material contaminado para a atmosfera da atual estrela de bário. A companheira evolui então para anã branca deixando de ser observada diretamente. As estrelas de bário são, portanto, úteis como testes observacionais para teorias de nucleossíntese pelo processo-s, convecção e perda de massa. Análises detalhadas de abundância com dados de alta qualidade para estes objetos são ainda escassas na literatura. Neste trabalho construímos modelos de atmosferas e, procedendo a uma análise diferencial, determinamos parâmetros atmosféricos e evolutivos de uma amostra de dez gigantes de bário e quatro normais. Determinamos seus padrões de abundância para Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, La, Ce, Nd, Sm, Eu e Gd, concluindo que algumas estrelas classificadas na literatura como gigantes de bário são na verdade gigantes normais. Comparamos dois padrões médios de abundância, para estrelas com grandes excessos e estrelas com excessos moderados, com modelos teóricos de enriquecimento pelo processo-s. Os dois grupos de estrelas são ajustados pelos mesmos parâmetros de exposição de nêutrons. Tal resultado sugere que a ocorrência do fenômeno de bário com diferentes intensidades não se deve a diferentes exposições de nêutrons. Discutimos ainda efeitos nucleossintéticos, ligados ao processo-s, sugeridos na literatura para os elementos Cu, Mn, V e Sc.

Smiljanic, R. H. S.; Porto de Mello, G. F.; da Silva, L.

2003-08-01

179

Performance of an ortho-para concentration measurement cryostat for hydrogen  

NASA Astrophysics Data System (ADS)

In this paper the results of the performance tests of an ortho-para analyzer for hydrogen are presented. The measurement is based on the easy and reliable gauging of the adiabatic heat of conversion between the hydrogen allotropes. A hydrogen gas flow is brought to a defined temperature first by the means of a liquid nitrogen bath at 77 K. Subsequently it is led through a catalyst bed inside an adiabatic cell. The ortho-para ratio can be derived from a precise temperature measurement before and after the catalytic induced conversion. Vice versa, with a known para content of the hydrogen feed, the activity of a given catalyst sample can be determined. The discussion of the results of the performance tests includes a chapter for the essential proper preparation of the necessary ortho-para catalyst material and the use of a suitable database for the thermodynamic properties of orthohydrogen and parahydrogen. A slight drawback of this method is the relative large amount of hydrogen gas required compared to other ortho-para concentration measurements.

Essler, Juergen; Haberstroh, Christoph

2012-06-01

180

On the Ortho:Para Ratio of H+ 3 in Diffuse Molecular Clouds  

NASA Astrophysics Data System (ADS)

The excitation temperature T 01 derived from the relative intensities of the J = 0 (para) and J = 1 (ortho) rotational levels of H2 has been assumed to be an accurate measure of the kinetic temperature in interstellar environments. In diffuse molecular clouds, the average value of T 01 is ~70 K. However, the excitation temperature T(H+ 3) derived from the (J, K) = (1, 1) (para) and (1, 0) (ortho) rotational levels of H+ 3 has been observed to be ~30 K in the same types of environments. In this work, we present observations of H+ 3 in three additional diffuse cloud sight lines for which H2 measurements are available, showing that in four of five cases T 01 and T(H+ 3) are discrepant. We then examine the thermalization mechanisms for the ortho:para ratios of H+ 3 and H2, concluding that indeed T 01 is an accurate measure of the cloud kinetic temperature, while the ortho:para ratio of H+ 3 need not be thermal. By constructing a steady-state chemical model taking into account the nuclear spin dependence of reactions involving H+ 3, we show that the ortho:para ratio of H+ 3 in diffuse molecular clouds is likely governed by a competition between dissociative recombination with electrons and thermalization via reactive collisions with H2. Based in part on observations made with ESO Telescopes at the La Silla or Paranal Observatories under program ID 384.C-0618.

Crabtree, Kyle N.; Indriolo, Nick; Kreckel, Holger; Tom, Brian A.; McCall, Benjamin J.

2011-03-01

181

Allergic contact dermatitis to para-phenylenediamine in a tattoo: a case report.  

PubMed

It is highly popular among children and young adults to have temporary henna tattoos on their bodies in different colors and figures. Henna is a greenish natural powder obtained from the flowers and dry leaves of Lawsonia alba plant and its allergenicity is very low. Henna is also used in combination with other coloring substances such as para-phenylenediamine in order to darken the color and create a permanent tattoo effect. Para-phenylenediamine is a substance with high allergenicity potential and may cause serious allergic reactions. Here, we aimed to draw attention to the potential harms of para-phenylenediamine containing temporary tattoos by presenting a child patient who developed allergic contact dermatitis after having a scorpion-shaped temporary tattoo on his forearm. PMID:22909181

Turan, Hakan; Okur, Mesut; Kaya, Ertugrul; Gun, Emrah; Aliagaoglu, Cihangir

2012-08-22

182

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

2013-05-20

183

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

184

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

185

Use of thiosemicarbazone and para-nitrobenzoic acid in screening tests for anonymous mycobacteria  

PubMed Central

In screening for anonymous mycobacteria the use of thiosemicarbazone (10?g./ml.) may give rise to false positive results. Although these can usually be overcome by further tests, additional time and effort is required, which seriously limits the value of thiosemicarbazone as a true screening agent. Para-nitrobenzoic acid (500 ?g./ml.) has proved more satisfactory in our hands; no false positive results have been obtained and it has the additional advantage that strains of M. kansasii (usually thiosemicarbazone sensitive) are resistant to para-nitrobenzoic acid.

Barrie, John D.

1967-01-01

186

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

187

Para-magneto- and electro-optic microcavities for blue wavelength modulation.  

PubMed

We report on microcavities comprising para-magnetic garnet and electro-optic films (MPMEO) for modulation of the polarization rotation angle of light at near-UV wavelengths with a slight intensity change, with applying a low voltage. The MPMEO are composed of para-magnetic garnet and electro-optic films sandwiched between two Bragg mirrors. The microcavity states in MPMEO are split and yield both the large rotation angle and high optical efficiency. Significant enhancement and modulation by applied voltages are verified through a conventional matrix calculation approach. High optical efficiency (>90%) and large modulation (~90 degree) of the polarization rotation are proved. PMID:24105511

Goto, Taichi; Isogai, Ryosuke; Inoue, M

2013-08-26

188

ParaGraph-RTS: A parallel reduction-based run-time system  

SciTech Connect

We are investigating the use of the functional programming paradigm on multiprocessor computers. We have developed a parallel graph reduction run-time system called ParaGraph-RTS (Parallel Graph Reduction) that provides both significant amounts of exploitable parallelism and the robustness to support development of large scientific codes. This system allows us to empirically investigate the functional programming paradigm within computationally intensive application domains. In this paper, we describe an implementation of ParaGraph-RTS on a shared-memory multiprocessor. The implementation strategy reflects insights gained through performance characterizations of the reduction process. Preliminary performance results and analyses are presented. 8 refs., 4 figs.

Yantis, B.; Rich, D.; Michelsen, R.

1989-01-01

189

Currículo, competências e habilidades para o mercado de trabalho: estudo de caso  

Microsoft Academic Search

Resumo: Este estudo analisa a dinâmica curricular do curso de Administração de uma instituição de ensino superior de cunho privado localizada em Brasília, com o objetivo de investigar a compatibilidade dos currículos do curso de graduação em administração com as diretrizes curriculares para o curso e com as competências e habilidades exigidas pelo mercado de trabalho. Trata-se de pesquisa qualitativa,

Jacira da Silva Câmara

190

Beard dermatitis due to para-phenylenediamine use in Arabic men  

Microsoft Academic Search

The most common active ingredient in hair coloring is para-phenylenediamine (PPDA), which can produce contact dermatitis, particularly in persons who dye their scalp hair and in hairdressers. We have identified another group of patients also at risk, namely men from Arab countries, who commonly grow beards and dye them. We searched the computerized patient database at the Mayo Clinic for

Te-Shao Hsu; Mark D. P. Davis; Rokea el-Azhary; John F. Corbett; Lawrence E. Gibson

2001-01-01

191

Irradiation of para-aortic lymph node metastases from carcinoma of the cervix or endometrium  

SciTech Connect

Twenty-two patients with biopsy-proved para-aortic lymph node metastases from carcinoma of the cervix (15 patients) or endometrium (7 patients) received a median dose of 5,000 rad/25 fractions. Para-aortic nodal metastases were controlled in 77% of cases. Control was significantly lower following radical retroperitoneal lymph node dissection than less extensive sampling procedures. Obstruction of the small bowel developed in 3 patients with tumor recurrence in the para-aortic region. Eight of the 10 patients who were disease-free at 2 years received >5,000 rad. Three patients were still alive without disease at 129, 63, and 60 months, respectively. The 5-year disease-free survival rate was 40% for cervical cancer and 60% for endometrial cancer: in the former group, it was significantly different depending on whether the para-aortic nodes were irradiated (40%) or not (0%). The authors suggest that 5,000-5,500 rad in 5-5.5 weeks is well tolerated and can control aortic nodal metastases in cervical and possibly endometrial cancer.

Komaki, R.; Mattingly, R.F.; Hoffman, R.G.; Barber, S.W.; Satre, R.; Greenberg, M.

1983-04-01

192

para-Connected cyclophenylenes and hemispherical polyarenes: building blocks for single-walled carbon nanotubes?  

PubMed

Carbon nanotubes by design? Cyclo-para-phenylenes are monomers for the synthesis of armchair carbon nanotubes (see picture, right), and are also attractive fluorophores that display size-dependent emission properties. Geodesic polyarenes represent a realistic alternative for the rational design of carbon nanotubes through the chemical elongation of the hydrocarbon template (left). PMID:22549829

Bunz, Uwe H F; Menning, Sebastian; Martín, Nazario

2012-04-30

193

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

194

REVISÃO DE ESTUDOS CLÍNICOS DE ENFERMAGEM: UTILIZAÇÃO DE PAPAÍNA PARA O TRATAMENTO DE FERIDAS  

Microsoft Academic Search

RESUMO: RESUMO: RESUMO: RESUMO: RESUMO: A papaína tem sido utilizada pelo enfermeiro para o tratamento de diversas feridas. No entanto, necessita-se de evidências que demonstrem seu efeito no desbridamento e aceleração da cicatrização. Esta investigação, por meio de revisão de literatura, teve como objetivo compilar estudos realizados por enfermeiros brasileiros ou graduandos de enfermagem na literatura nacional e indexados nos

Adriano Menis Ferreira; Kleber Aparecido de Oliveira; Luiz Carlos Vieira; James da Luz Rol

195

‘Madrinas’: snitching\\/para?policing and the illegal support of police work in Mexico  

Microsoft Academic Search

This paper analyzes the institutional role of informal para?police groups in Mexico known as ‘madrinas.’ The specific characteristics of ‘madrinas’ are that they are run as complex?structured networks with hierarchies, they actively participate in police activities, and they are an alternative way of gaining entry into the police institution. However, their key function is intelligence work within the police agency

Gustavo Fondevila

2011-01-01

196

SIGNIFICANT STRUCTURE THEORY OF LIQUID HYDROGEN IN ITS VARIOUS ORTHO-PARA AND ISOTOPIC FORMS  

Microsoft Academic Search

The significant structure theory of liquids was extended to include ; liquid hydrogen in its various ortho-para and isotopic forms. It was assumed ; that liquid hydrogen has a quasi-lattice structure in which the latiicc sites'' ; are occupied either by hydrogen molecules or holes of molecular size. Such a ; hole will confer gas-like properties on a molecule which

Douglas Henderson; Henry Eyring; Dale Felix

1962-01-01

197

ACTIVIDADES PARA DESARROLLAR LA EXPRESIÓN ORAL Y ESCRITA DEL TÉCNICO MEDIO EN CONTABILIDAD  

Microsoft Academic Search

El siguiente trabajo responde a un problema que enfrenta el C\\/P Osvaldo Socarrás Martínez, relacionado con las insuficiencias que afectan el desarrollo de la Lengua Materna en los estudiantes, por lo que el objetivo de la misma es el de la elaboración de actividades para favorecer la expresión oral y escrita en los estudiantes del segundo año de técnico medio

Orlando Martínez Cuba; Lisandra Ávila Arzuaga

2010-01-01

198

Notes on a Critical Edition of Para las seis cuerdas by Jorge Luis Borges  

Microsoft Academic Search

Jorge Luis Borges orchestrated the canonization of his work, culminating in his Obras completas. The traces of this editorial endeavor are effaced in what Borges conceived as his complete works. The analysis of the various editions of Para las seis cuerdas demonstrates that the rationale behind the editorial changes is a conscious effort to present a collection of milongas with

Robert Folger

2001-01-01

199

Para-ferrimagnetic transition in strong coupling paramagnetic systems: Landau theory approach  

Microsoft Academic Search

We consider here the continuous Landau model describing the para-ferrimagnetic transition, in two strongly coupled Pauli-paramagnetic sublattices, with respective magnetic moments m and M. The free energy of the system contains, in addition to quadratic and quartic terms in both moments m and M, a coupling term — CmM, where C < 0 is the coupling constant between the two

B. El Houari; M. Benhamou; M. El Hafidi; G. Chouteau

1997-01-01

200

Adubação verde como alternativa agroecológica para recuperação da fertilidade do solo  

Microsoft Academic Search

A recuperação da fertilidade do solo, especialmente do nutriente fósforo (P) tem custo bastante elevado, principalmente quando utilizadas fontes de adubos solúveis. Portanto, é necessário encontrar alternativas de menor custo para recuperação da fertilidade-P. O objetivo desse trabalho foi de avaliar o potencial de produtividade de fi tomassa de espécies de adubos verdes de verão e de inverno submetidas a

Cristiano André Pott; Marcelo Marques; Lopes Müller; Patrick Batista Bertelli

201

ANÁLISE ECONÔMICA DE SUCESSÕES DE CULTURAS PARA MILHO, COM NÍVEIS DE NITROGÊNIO EM COBERTURA  

Microsoft Academic Search

RESUMO - O milho é uma cultura presente em todas as regiões brasileiras; nos últimos anos, seus custos de produção aumentaram. Técnicas que proporcionem economia, sem perda de produtividade, podem incentivar seu cultivo, tão importante no sistema de rota- ção de culturas. Os adubos verdes são opções para a redução de custos, principalmente em relação ao nitrogênio. Utilizaram-se dados de

DENIS AUGUSTO DA SILVA; CARLOS FERREIRA DE SOUZA

202

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

203

Spontaneous Reactivation of Acetylcholinesterase Inhibited with Para-Substituted Phenyl Methylphosphonochloridates.  

National Technical Information Service (NTIS)

Four para-substituted phenyl methylphosphonochloridates (H, I; CH3O, II; NO2, III; and CN, IV) were prepared by reaction of excess methyl phosphonodichloridate with the appropriate phenol. The rates of hydrolysis of I-IV were determined at pH 4.90 and sho...

J. W. Hovanec C. N. Lieske

1972-01-01

204

Chiral aryl iodide catalysts for the enantioselective synthesis of para-quinols.  

PubMed

Molecular modelling of an iodine(III) phenoxide was used as a starting point in the design of chiral aryl iodide catalysts for stereoselective oxidative dearomatization reactions. Using this approach, catalysts derived from 8-iodotetralone and tartaric acid were constructed and used to synthesize enantioenriched para-quinols from phenols. PMID:23463273

Volp, Kelly A; Harned, Andrew M

2013-04-14

205

The accountability of para-governmental organizations (bonyads): the case of Iranian foundations  

Microsoft Academic Search

This paper attempts to explain the emergence and development of para-governmental organizations (bonyads) in Iran and demonstrate their contradictory position in the Iranian political economy. These organizations represent the dual power structure in Iran which reinforces the financial authority of religious leaders without accountability. By analyzing the functions of these organizations, the paper sets out to probe their economic policies

Ali A. Saeidi

2004-01-01

206

Energia Renovable para Centros de Salud Rurales (Renewable Energy for Rural Health Clinics)  

Microsoft Academic Search

Esta es la primera de una serie de guias de aplicaciones que el Programa de Energia de Villas de NREL esta comisionando para acoplar sistemas comerciales renovables con aplicaciones rurales, incluyendo agua, escuelas rurales y micro empresas. La guia esta complementada por las actividades de desarrollo del Programa de Energia de Villas de NREL, proyectos pilotos internacionales y programas de

T. Jimenez; K. Olson

1999-01-01

207

Interrupting Commemoration: Thinking with Art, Thinking through the Strictures of Argentina's "Espacio para la memoria"  

ERIC Educational Resources Information Center

Recently, a few buildings within the "Espacio para la memoria" in Buenos Aires have been designated as a UNESCO Centre where, amongst other educational activities, evidentiary materials of the past repression are to be stored and displayed. Another building in the complex houses a Community Centre operated by the Mothers of the Plaza de Mayo,…

Paolantonio, Mario Di

2011-01-01

208

Triadic analysis of substituent effects—gas-phase acidity of para-substituted phenols  

Microsoft Academic Search

A large variety of para-substituted phenols was examined and their acidities in the gas-phase were rationalized by a triadic formula, which is capable of delineating the initial, intermediate and final state effects in the deprotonation process. It is shown that triadic analysis is equivalent to the homodesmotic reactions approach, while being much more informative at the same time. The applied

Robert Vianello; Zvonimir B. Maksi?

2006-01-01

209

Programação de uma Rede de Sensores para o Corpo Humano por meio de uma Interface Gráfica  

Microsoft Academic Search

Palavras-chave: Redes de Sensores para o Corpo Humano (RSCH), autômatos, multiprogramação, Java Abstract - The inherent characteristics of the Body Sensor Networks (BSN) have a great potential to influence clinical applications for the next decades. It can promote a new paradigm for health monitoring based on wearable systems. The handling of a BSN through a command-line programming interface may not

Talles M. G. A. Barbosa; Iwens G. Sene Jr; F. Rocha; Francisco A. O. Nascimento; S. Carvalho

210

EFECTO DE LA NUTRICIÓN Y OTROS FACTORES PARA ASEGURAR UN CRECIMIENTO ÓPTIMO EN EL POTRO  

Microsoft Academic Search

El objetivo de criar potros puede ser venderlos, presentarlos en concursos morfológicos o quedarse con ellos para luego presentarlos a una competición. Sea cual sea el futuro del potro, hay que asegurarse que el animal goza de salud y puede llegar a ser un atleta con un esqueleto y un cuerpo que aguante el trabajo suficientemente. Existen muchos factores que

Pat Harris

211

MONITORAMENTO DOS NINHOS ARTIFICIAIS INSTALADOS PARA AS ARARAS-AZUIS (Anodorhynchus hyacinthinus)  

Microsoft Academic Search

Ameaçada de extinção e com baixa taxa reprodutiva, um dos fatores limitantes à reprodução da arara-azul Anodorhynchus hyacinthinus, no Pantanal é a escassez de cavidades em árvores. Além disso, no mesmo período de reprodução das araras-azuis outras espécies de aves estão se reproduzindo e a disputa pelos ninhos é grande. Para minimizar este fator, instalamos 70 ninhos artificiais, no período

Rua Klaus Sturk; Jd Mansur; Neiva Maria; R. Guedes; Torborg Berge; Vanessa M. B; Márcia M. Volpe; Carolina Ribas; Arara Azul

212

Novas perspectivas para o diagnóstico da artrite reumatóide New perspectives for the diagnosis of rheumatoid arthritis  

Microsoft Academic Search

SINOPSE Este artigo consiste em uma revisão da literatura médica sobre o diagnóstico da artri- te reumatóide, com ênfase sobre as novas perspectivas para o mesmo. Dentre essas novas possibilidades, vários marcadores sorológicos têm-se destacado, principalmente os auto- anticorpos antiperinuclear (fator antiperinuclear - FAP) e antiqueratina (anticorpo anti- queratina - AKA), pela alta especificidade. Esses podem auxiliar no diagnóstico inicial

Lia Andrade Zorzi

213

Energia Renovable para Centros de Salud Rurales (Renewable Energy for Rural Health Clinics)  

SciTech Connect

Esta es la primera de una serie de guias de aplicaciones que el Programa de Energia de Villas de NREL esta comisionando para acoplar sistemas comerciales renovables con aplicaciones rurales, incluyendo agua, escuelas rurales y micro empresas. La guia esta complementada por las actividades de desarrollo del Programa de Energia de Villas de NREL, proyectos pilotos internacionales y programas de visitas profesionales.

Jimenez, T.; Olson, K.

1999-07-28

214

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

215

Hacia la implementación de una guía de práctica clínica para el tratamiento del asma  

Microsoft Academic Search

Abstract. Dados los esfuerzos que el personal sanitario hace para la definición de guías de práctica clínica (CPG) por su elevado impacto en la calidad de los cuidados y la dificultad de su implantación, hemos considerado necesario desarrollar una,solución efectivade cara a laimplantación de CPGsmediante Sistemas de Ayuda a la Toma de Decisiones (DSS). Por la importancia de lo antedicho,

Pikatza F. J; Lopez de Ipiña

216

Evaluación paramétrica y no paramétrica del desempleo pesquero en Marruecos: Una aplicación para el caso andaluz  

Microsoft Academic Search

RESUMEN El principal objetivo es el análisis de las medidas que las diferentes administraciones pusieron en marcha para reducir las altas tasas de desempleo en la población andaluza afectada por la paralización de la actividad pesquera como consecuencia de la finalización del Acuerdo de Pesca entre la Unión Europea y Marruecos desde el 30 de noviembre de 1999. Mediante la

Encarnación Cordón Lagares; Félix García Ordaz

2010-01-01

217

El desarrollo de la escucha como habilidad para comprender, a partir de la asignatura inglés  

Microsoft Academic Search

Este artículo aborda una problemática actual al profundizar en el desarrollo de la habilidad Escuchar como habilidad para comprender, se hace una sistematización de conocimientos teóricos sobre la temática, se intenta mostrar cómo una actividad común de audición encontrada en la mayoría de los libros de texto modernos de la enseñanza del EFL (inglés como idioma extranjero), puede ser explotada

Rafael Lorenzo Hechavarría Pérez

2011-01-01

218

Validez y confiabilidad de tres escalas para evaluar conductas sociales en preescolares y escolares  

Microsoft Academic Search

Resumen: Estudiamos la validez y confiabilidad de tres escalas para eva- luar conductas sociales niños y niñas costarricenses de preescolar y primer grado (n=262). Una de las escalas evalúa el comportamiento prosocial (ECPRO), otra evalúa la habilidad de explotar la experticia de los demás (EXHAD), y una más evalúa el comportamiento maquiavélico (EMach) en el ámbito escolar. Las escalas son

Odir Rodríguez Villagra; Michael Padilla Mora; Jaime Fornaguera Trías

2010-01-01

219

The Role of Adsorption in the Catalytic Para-Ortho-Hydrogen Conversion.  

National Technical Information Service (NTIS)

Adsorption isotherms were determined for two para-ortho-hydrogen conversion catalysts, hydrous ferric oxide gel and nickel oxide silicate, at temperatures from 63K to 196K and at pressures from 1 to 10 atmospheres. For the catalysts studied, Langmuir's Is...

H. R. Lander

1967-01-01

220

REDE ISOBUS PARA CONTROLE E COMUNICAÇÃO DE DADOS DE UM ROBÔ AGRÍCOLA MÓVEL  

Microsoft Academic Search

RESUMO: Diante da grande necessidade de se projetar máquinas e implementos agrícolas cada vez mais automatizadas, uma forte tendência atual é o desenvolvimento de robôs móveis e veículos autônomos para área agrícola. Estes robôs e veículos, implementados com as mesmas tecnologias existentes em máquinas agrícolas, desempenham tarefas específicas com grande eficiência, originado ganhos de operação quando comparados a utilização de

EDUARDO PACIÊNCIA GODOY; GIOVANA TRIPOLONI TANGERINO; RAFAEL VIEIRA DE SOUSA; ARTHUR JOSÉ VIEIRA PORTO; RICARDO YASSUSHI INAMASU

221

Dielectric relaxation of para polar liquids under high frequency electric field  

Microsoft Academic Search

The structural and associational aspects of nonspherical para polar liquids (j) in nonpolar solvents (i) are studied through high frequency conductivities ?ij's of solutions. The relaxation time ? of the respective liquids under 3cm. wavelength electric field at various experimental temperatures in °C are estimated from the slope of individual variations of real ??ij and imaginary ??ij parts of hf

N Ghosh; R. C Basak; S. K Sit; S Acharyya

2000-01-01

222

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

223

More constraint on ParaHox than Hox gene families in early metazoan evolution.  

PubMed

Hox and ParaHox (H/P) genes belong to evolutionary-sister clusters that arose through duplication of a ProtoHOX cluster early in animal evolution. In contrast to bilaterians, cnidarians express, beside PG1, PG2 and Gsx orthologs, numerous Hox-related genes with unclear origin. We characterized from marine hydrozoans three novel Hox-related genes expressed at medusa and polyp stages, which include a Pdx/Xlox ParaHox ortholog induced 1 day later than Gsx during embryonic development. To reconstruct H/P genes' early evolution, we performed multiple systematic comparative phylogenetic analyses, which identified derived sequences that blur the phylogenetic picture, recorded dramatically different evolutionary rates between ParaHox and Hox in cnidarians and showed the unexpected grouping of [Gsx-Pdx/Xlox-PG2-PG3] families in a single metagroup distinct from PG1. We propose a novel more parsimonious evolutionary scenario whereby H/P genes originated from a [Gsx-Pdx/Xlox-PG2-PG3]-related ProtoHox gene, the "posterior" and "anterior" H/P genes appearing secondarily. The ProtoHOX cluster would have contained the three Gsx/PG2, Pdx/PG3, Cdx/PG9 paralogs and produced through tandem duplication the primordial HOX and ParaHOX clusters in the Cnidaria-Bilateria ancestor. The stronger constraint on cnidarian ParaHox genes suggests that the primary function of pre-bilaterian H/P genes was to drive cellular evolutionary novelties such as neurogenesis rather than axis specification. PMID:19389364

Quiquand, Manon; Yanze, Nathalie; Schmich, Jürgen; Schmid, Volker; Galliot, Brigitte; Piraino, Stefano

2009-01-27

224

ParA2, a Vibrio cholerae chromosome partitioning protein, forms left-handed helical filaments on DNA  

PubMed Central

Most bacterial chromosomes contain homologs of plasmid partitioning (par) loci. These loci encode ATPases called ParA that are thought to contribute to the mechanical force required for chromosome and plasmid segregation. In Vibrio cholerae, the chromosome II (chrII) par locus is essential for chrII segregation. Here, we found that purified ParA2 had ATPase activities comparable to other ParA homologs, but, unlike many other ParA homologs, did not form high molecular weight complexes in the presence of ATP alone. Instead, formation of high molecular weight ParA2 polymers required DNA. Electron microscopy and three-dimensional reconstruction revealed that ParA2 formed bipolar helical filaments on double-stranded DNA in a sequence-independent manner. These filaments had a distinct change in pitch when ParA2 was polymerized in the presence of ATP versus in the absence of a nucleotide cofactor. Fitting a crystal structure of a ParA protein into our filament reconstruction showed how a dimer of ParA2 binds the DNA. The filaments formed with ATP are left-handed, but surprisingly these filaments exert no topological changes on the right-handed B-DNA to which they are bound. The stoichiometry of binding is one dimer for every eight base pairs, and this determines the geometry of the ParA2 filaments with 4.4 dimers per 120 ? pitch left-handed turn. Our findings will be critical for understanding how ParA proteins function in plasmid and chromosome segregation.

Hui, Monica P.; Galkin, Vitold E.; Yu, Xiong; Stasiak, Alicja Z.; Stasiak, Andrzej; Waldor, Matthew K.; Egelman, Edward H.

2010-01-01

225

MECANISMOS PARA LA CREACIÓN DE HÉROES Y ANTI HÉROES PARA LA OPINIÓN PÚBLICA INTERNACIONAL EN PERIODOS DE GUERRA HOW MEDIA CREATES HEROS AND ANTIHEROS FOR THE INTERNATIONAL PUBLIC OPINION IN WAR PERIODS  

Microsoft Academic Search

La intención principal de esta investigación es encontrar las claves que se utilizan a diario en los medios de comunicación para crear, de cara a la opinión pública, héroes y anti -héroes en periodos de crisis internacional como los que se vienen viendo desde el pasado 11 de septiembre. Para plantear esta investigación partimos de dos ideas. La primera de

García Gordillo

226

SISTEMA DE ACTIVIDADES PARA FORTALECER LA PREPARACIÓN DE LOS PROFESIONALES EN EL LABORATORIO CLÍNICO ROSA ELENA SIMEÓN DE LA SIERPE  

Microsoft Academic Search

Los laboratorios de análisis clínicos constituyen un área en la cual coinciden muchos agentes potencialmente agresivos, tanto para la salud del personal y de las personas que acuden a recibir los servicios que se prestan, así como para las propias instalaciones. Debido a ello, todos los procedimientos analíticos conllevan a un riesgo, que aumenta con la introducción de nuevas tecnologías,

José Sánchez Díaz; Caridad Milanés Reyes; Osvel García Riverón

2011-01-01

227

PROPUESTA DE ESTRATEGIA DIDÁCTICA PARA EL DESARROLLO DE HABILIDADES PROFESIONALES EN LA CARRERA DE INGENIERÍA EN PROCESOS AGROINDUSTRIALES  

Microsoft Academic Search

En el presente artículo se expone una propuesta de estrategia didáctica para el uso de las Tecnologías de la Información y las Comunicaciones (TIC) en la Carrera de Ingeniería de Procesos Agroindustriales en el proceso de enseñanza-aprendizaje semipresencial. En el trabajo se muestran elementos que constituyen un importante soporte para el desarrollo de la docencia y la apropiación de conocimientos

Marilin Teruel Mulet; Xiomara Maritza Rodríguez Tamayo; Yimmy Omar Acedo Martín

2010-01-01

228

Un nuevo estudio de terapias dirigidas para cáncer de mama establece un modelo de estudios clínicos a nivel mundial  

Cancer.gov

Dos medicamentos dirigidos, diseñados para tratar una forma agresiva de cáncer de seno o mama, están siendo probados en un estudio nuevo que incluye a 8 000 participantes en 50 países de seis continentes. Éste será un estudio clínico que los investigadores esperan proporcionará un nuevo modelo para la investigación del cáncer a nivel mundial. Preguntas y respuestas

229

FARINHA MISTA DE MANDIOCA COM CASTANHA-DO-BRASIL: UMA ALTERNATIVA AGROECOLÓGICA PARA A RESERVA EXTRATIVISTA CAZUMBÁ-IRACEMA  

Microsoft Academic Search

A farinha de mandioca é o principal produto em importância alimentar servindo como fonte de energia e geração de renda para os agricultores familiares da Amazônia. A castanha-do-brasil é uma das principais fontes de proteína vegetal, geração de emprego e renda para os extrativistas da Amazônia. Este trabalho teve como objetivo analisar o arranjo produtivo local da farinha mista de

Amauri Siviero; Carlo Filipe E. Raimundo; Lauro Saraiva Lessa; Thiago Andres Delunardo; Oscar Borreani Pardinas

2008-01-01

230

Impact of para-phenylenediamine on cyclooxygenases expression and prostaglandin formation in human immortalized keratinocytes (HaCaT)  

Microsoft Academic Search

para-Phenylenediamine, a monocyclic arylamine, is a frequently used chemical and ingredient of oxidative hair coloring products. Thus exposure occurs predominantly via skin. Cyclooxygenases, the key enzymes in prostaglandin synthesis, exhibit manifold physiological and pathophysiologial functions in skin and skin cells such as keratinocytes. We studied if para-phenylenediamine impacts on the expression of enzymes in the cyclooxygenase pathway in human immortalized

Ruth Moeller; Jutta Lichter; Brunhilde Blömeke

2008-01-01

231

Zoneamento agrícola e época de semeadura para trigo no Brasil Agricultural zoning and sowing dates for wheat in Brazil  

Microsoft Academic Search

Resumo - Um Programa de Zoneamento Agrícola para o Brasil, subsidiando a política de crédito e securidade rural, começou a ser posto em prática pelo Ministério da Agricultura, Pecuária e Abastecimento (MAPA) a partir da safra de inverno de 1996, com a cultura de trigo no sul do Brasil. Este artigo apresenta uma síntese dos trabalhos sobre zoneamento agrícola para

Gilberto Rocca da Cunha; João Carlos Haas; Jaime Ricardo; Tavares Maluf; Paulo Henrique Caramori; Eduardo Delgado Assad; Hugo José Braga; Jurandir Zullo Jr; Cláudio Lazzarotto; Sérgio Gonçalves; Marcos Wrege; Dionísio Brunetta; Sérgio Roberto Dotto; Hilton Silveira Pinto; Orivaldo Brunini; Vera Magali; Radtke Thomé; Sérgio Luiz Zampieri; Aldemir Pasinato; Márcia Barrocas Moreira Pimentel; Cristina Pandolfo

2001-01-01

232

Reciclagem de sucata de jóias para a recuperação hidrometalúrgica de prata Jewel scrap recycling for the silver hydrometallurgical recovery  

Microsoft Academic Search

Muitos resíduos valiosos gerados na fabricação de jóias se perdem pela falta de conhecimento técnico para a recuperação dos metais preciosos utilizados na sua elaboração. Esse trabalho apresenta os resultados experimentais do uso de uma rota hidrometalúrgica, em escala de bancada laboratorial, para tratar amostras de sucatas de jóias à base de ouro (Au) com teores de prata (Ag) acima

Carol Elizabeth; Barrientos Rojas; Afonso Henriques Martins

2009-01-01

233

DETERMINACIÓN Y CARACTERIZACIÓN DE MICROORGANISMOS PRESENTES EN LA MASA PARA TORTILLA DE MAÍZ EN TORTILLERIAS DEL MUNICIPIO DE SALTILLO, COAHUILA  

Microsoft Academic Search

La tortilla es un producto alimenticio derivado del maíz y es de muy alto consumo en nuestro país. La elaboración de la masa para tortilla esta constituida por las siguientes materias primas como es el maíz, agua y óxido de calcio (Cal). 5 La otra manera más sencilla para preparar la masa es mediante la mezcla de harinas instantáneas y

Q. F. B. Flores; Chávez Héctor; Q. F. B. Zamora de los; Villarreal López

234

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

235

COMPARACIÓN DE VARIOS MÉTODOS PARA LA REPRESENTACIÓN CARTOGRÁFICA DE INFORMACIÓN CLIMÁTICA EN ZONAS ALTAS DEL ESTADO LARA  

Microsoft Academic Search

Se compararon tres métodos cartográficos diferentes para la representación de aspectos climáticos (temperatura y precipitación) en zonas altas del estado Lara. Se usó conjuntamente A) Representación analógica (en papel), B) Mapas digitalizados de coberturas mediante el software para Sistema de Información Geográfica (SIG) ArcInfo y C) Modelos numéricos interpolados mediante software de aplicación geoestadística (SURFER), empleando el modelo de interpolación

Jorge López Márquez; Rigoberto Andressen

2001-01-01

236

Cómo medir la quiebra de las empresas en Santander, el modelo logístico: una herramienta para evaluar el riesgo de quiebra  

Microsoft Academic Search

Las propuestas contenidas en el documento del Nuevo Acuerdo de Capital de Basilea, para medir el riesgo de crédito, sirven de base para medir también el riesgo de quiebra de las empresas con base en la utilización de ratios financieros internos. En la práctica se presentan situaciones en la que es necesario tomar decisiones de acuerdo con el comportamiento de

José Joaquín Alzate Marín

2008-01-01

237

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

238

The Impact of Family Support on the Success of Black Men at an Historically Black University: Affirming the Revision of Tinto's Theory  

ERIC Educational Resources Information Center

|This qualitative study of 11 Black male students who entered a public historically Black college and university (HBCU) as academically under-prepared and persisted to graduation, provides insight into the ways in which family promotes academic success for Black male students at a public HBCU. The study's findings encourage practitioners at HBCUs…

Palmer, Robert T.; Davis, Ryan J.; Maramba, Dina C.

2011-01-01

239

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

PubMed

Several H2CS ortho and para transitions have been observed toward interstellar molecular clouds, including cold, dark clouds and star-forming regions. We derive H2CS fractional abundances f(H2CS) approximately 1-2 10(-9) relative to molecular hydrogen towards TMC-1, Orion A, and NGC 7538, and approximately 5 10(-10) for L134N. The H2CS ortho-to-para ratios in TMC-1 are approximately 1.8 towards the cyanopolyyne peak and the ammonia peak, which may indicate the thermalization of H2CS on 10 K grains. We derive a ratio of approximately 3, the statistical value, for Orion (3N, 1E) and NGC 7538, while we find a value approximately 2 for Orion (KL). PMID:11538284

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

1991-01-01

240

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

241

Sasaki-Einstein and paraSasaki-Einstein metrics from (?,?)-structures  

NASA Astrophysics Data System (ADS)

We prove that every contact metric (?,?)-space admits a canonical ?-Einstein Sasakian or ?-Einstein paraSasakian metric. An explicit expression for the curvature tensor fields of those metrics is given and we find the values of ? and ? for which such metrics are Sasaki-Einstein and paraSasaki-Einstein. Conversely, we prove that, under some natural assumptions, a K-contact or K-paracontact manifold foliated by two mutually orthogonal, totally geodesic Legendre foliations admits a contact metric (?,?)-structure. Furthermore, we apply the above results to the geometry of tangent sphere bundles and we discuss some geometric properties of (?,?)-spaces related to the existence of Einstein-Weyl and Lorentzian-Sasaki-Einstein structures.

Cappelletti-Montano, Beniamino; Carriazo, Alfonso; Martín-Molina, Verónica

2013-11-01

242

pH-dependent nitration of para-hydroxyphenylacetic acid in the stomach  

Microsoft Academic Search

The major urinary metabolite of nitrotyrosine is 3-nitro-4-hydroxyphenylacetic acid (3-Nitro-HPA). However, recent animal studies have shown that the majority of urinary 3-Nitro-HPA is derived from nitration of endogenous para-hydroxyphenylacetic acid (HPA), a metabolite of tyrosine. One potential site for the formation of 3-Nitro-HPA is the stomach, where nitrous acid is formed by the reaction of nitrite in saliva with gastric

Ananth S. Pannala; Ali R. Mani; Catherine A. Rice-Evans; Kevin P. Moore

2006-01-01

243

Mercury Exposures in Riverside Amazon Communities in ParaH , Brazil1  

Microsoft Academic Search

Cross-sectional studies were conducted in three riverside communities in the state of ParaH in the Amazon Region of Brazil. Two of these communi- ties, Bras1H lia Legal and Sa8 oL u1H s do TapajoH s, are located in a watershed exposed to mercury pollu- tion from artisanal gold mining, and the third, San- tana do Ituqui, is outside this area.

Elisabeth C. de Oliveira Santos; Iracina Maura de Jesus; Edilson da Silva Brabo; Edvaldo C. Brito Loureiro; Artur F. da Silva Mascarenhas

244

Structure of and electric conduction in metal–polymer poly- para -xylylene–Ag nanocomposite films  

Microsoft Academic Search

The processes of formation of metal-polymer poly-para-xylylene-Ag nanocomposites by solidphase cryochemical synthesis are studied. The temperature dependences of the electrical\\u000a resistivity of the composites measured in the course of polymerization, which involves heating the cocondensate of p-xylylene monomer and metal particles, and on completion of the polymerization are presented. The findings are correlated\\u000a to the results of the structural investigation

I. A. Boginskaya; A. V. Gusev; K. A. Mailyan; S. N. Ozerin; A. V. Pebalk; I. A. Ryzhikov; M. V. Sedova; S. N. Chvalun

2011-01-01

245

Raman, surface-enhanced Raman scattering and DFT study of para-nitro-aniline  

Microsoft Academic Search

Raman spectra of para-nitro-aniline (pNA), a molecule with high applicability potential in molecular electronics, were recorded in solid state and in ethanol solution. Complete assignment of the experimental spectra was made by using the B3LYP\\/6-31G(d) theoretical results. The calculated molecular electrostatic potential shows a high negative charge localized on the nitro group of pNA and the surface-enhanced Raman scattering (SERS)

Vasile Chi?; Monica M. Venter; Nicolae Leopold; Onuc Cozar

2008-01-01

246

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.

247

Parallel Visualization and Analysis with ParaView on a Cray XT4  

SciTech Connect

Scienti c data sets produced by modern supercomputers like ORNL s Cray XT 4, Jaguar, can be extremely large, making visualization and analysis more di cult as moving large resultant data to dedicated analysis systems can be pro- hibitively expensive. We share our continuing work of integrating a parallel visu- alization system, ParaView, on ORNL s Jaguar system and our e orts to enable extreme scale interactive data visualization and analysis. We will discuss porting challenges and present performance numbers.

Patchett, John [Los Alamos National Laboratory (LANL); Ahrens, James [Los Alamos National Laboratory (LANL); Ahern, Sean [ORNL; Pugmire, Dave [ORNL

2009-01-01

248

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

249

D2 Lymphadenectomy Alone or with Para-aortic Nodal Dissection for Gastric Cancer  

Microsoft Academic Search

Background Gastrectomy with D2 lymphadenectomy is the standard treatment for curable gastric cancer in eastern Asia. Whether the addition of para-aortic nodal dissection (PAND) to D2 lymphadenectomy for stage T2, T3, or T4 tumors improves survival is contro- versial. We conducted a randomized, controlled trial at 24 hospitals in Japan to com- pare D2 lymphadenectomy alone with D2 lymphadenectomy plus

Mitsuru Sasako; Takeshi Sano; Seiichiro Yamamoto; Yukinori Kurokawa; Atsushi Nashimoto; Akira Kurita; Masahiro Hiratsuka; Toshimasa Tsujinaka; Taira Kinoshita; Kuniyoshi Arai; Yoshitaka Yamamura; Kunio Okajima

2008-01-01

250

Characterization of the Role of para-Aminobenzoic Acid Biosynthesis in Folate Production by Lactococcus lactis  

Microsoft Academic Search

The pab genes for para-aminobenzoic acid (pABA) biosynthesis in Lactococcus lactis were identified and characterized. In L. lactis NZ9000, only two of the three genes needed for pABA production were initially found. No gene coding for 4-amino-4-deoxychorismate lyase (pabC) was initially annotated, but detailed analysis revealed that pabC was fused with the 3 end of the gene coding for chorismate

Arno Wegkamp; Wietske van Oorschot; Willem M. de Vos; Eddy J. Smid

2007-01-01

251

Para-ferrimagnetic transition in strong coupling paramagnetic systems: Landau theory approach  

Microsoft Academic Search

We consider here the continuous Landau model describing the para-ferrimagnetic transition, in two strongly coupled Pauli-paramagnetic sublattices, with respective magnetic moments m and M. The free energy of the system contains, in addition to quadratic and quartic terms in both moments m and M, a coupling term -CmM, where C < 0 is the coupling constant between the two sublattices.

B. El Houari; M. Benhamou; M. El Hafidi; G. Chouteau

1997-01-01

252

Passivation of iron-based alloys in para-toluene sulfonic acid  

Microsoft Academic Search

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.

Iuan-Jou Yang; Mao Ying Teng

1993-01-01

253

Sorption of water vapors by high-strength para-aramid fibres  

Microsoft Academic Search

The water vapor sorption isotherms were measured for different types of high-strength fibres based on carbocyclic and heterocyclic\\u000a para-aramids: Rusar (copolymers of amidobenzimidazole and p-phenylene terephthalamide), Twaron and Kevlar (poly-p-phenylene\\u000a terephthalamide), and for comparison, capron (polycaproamide). The parameters of the thermal sorption equation and the thermodynamic\\u000a characteristics of sorption of water vapor were calculated with previously obtained sorption data with

K. E. Perepelkin; S. F. Grebennikov; N. P. Lebedeva

2007-01-01

254

Influence of Avatar Creation on Attitude, Empathy, Presence, and Para-Social Interaction  

Microsoft Academic Search

The present paper focuses on the influence of avatar creation in a video game. More specifically, this study investigates\\u000a the effects of avatar creation on attitude towards avatar, empathy, presence, and para-social interaction of female non-game\\u000a users. As a cyber-self, an avatar is a graphic character representing a user in cyberspace. Avatars are primarily used in\\u000a the entertainment industry as

Donghun Chung; Brahm Daniel Debuys; Chang S. Nam

2007-01-01

255

Effect of antioxidants on para-aminophenol-induced toxicity in LLC-PK 1 cells  

Microsoft Academic Search

The present studies were designed to investigate the susceptibility of LLC-PK1 cells to cytotoxicity induced by para-aminophenol (PAP) and the ability of antioxidants to prevent PAP-induced cytotoxicity. LLC-PK1 cells were incubated for 4 h with varying concentrations of PAP (0–0.2 mM). Incubation was continued for 20 h and viability was monitored at 24 h after initial exposure to PAP. For

Mark A. Hallman; Ruy Tchao; Joan B. Tarloff

2000-01-01

256

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

257

Autosomal recessive retinitis pigmentosa with preserved para-arteriolar retinal pigment epithelium.  

PubMed

Retinitis pigmentosa with preserved para-arteriolar retinal pigment epithelium is a rare form of retinitis pigmentosa that starts early in life with preservation of retinal pigment epithelium adjacent to and under the retinal arterioles and that has hitherto been described as an isolated form. We examined 22 patients from one large family, together with two isolated patients, and confirmed the presumed autosomal recessive mode of inheritance in this type of retinitis pigmentosa. New findings associated with retinitis pigmentosa with preserved para-arteriolar retinal pigment epithelium were asteroid hyalosis in four (17%) of 24 patients, tortuosity of retinal arterioles in 11 (46%) of 24 patients, peripheral regions of opacified vessels in eight (33%) of 24 patients, and preservation not only of the para-arteriolar pigment epithelium, but also of the peripheral retinal pigment epithelium in 13 (54%) of 24 patients. Previously reported signs present in these patients were nystagmus in six (25%) of 24 patients, hypermetropia in 23 (96%) of 24 patients, optic nerve head drusen in nine (38%) of 24 patients, vascular sheathing in 11 (46%) of 24 patients, maculopathy in all 24 patients (100%), yellow round deposits in the posterior pole in nine (38%) of 24 patients, exudates resembling those in Coats' disease in two (8%) of 24 patients, visual field defects in all 24 patients (100%), and nondeductible electroretinograms in 21 (91%) of 23 patients. Linkage analysis carried out in the large family resulted in the assignment of a gene for retinitis pigmentosa with preserved para-arteriolar retinal pigment epithelium to chromosome 1q31-q32.1. PMID:7943119

van den Born, L I; van Soest, S; van Schooneveld, M J; Riemslag, F C; de Jong, P T; Bleeker-Wagemakers, E M

1994-10-15

258

Hydroformylation of endocyclic double bonds in para-menthenic terpenes under mild conditions  

Microsoft Academic Search

Rhodium-catalyzed hydroformylation of a series of para-menthenic terpenes, i.e., terpinolene (1), ?-terpinene (2), and ?-terpinene (3), has been studied. The hydroformylation of conjugated diene 3 can be performed at a reasonable rate using triphenylphosphine as an auxiliary ligand (P\\/Rh=20), whereas non-conjugated dienes 1 and 2 have showed an extremely low reactivity in the Rh\\/PPh3 system. The use of a bulky

José G. da Silva; Camila G. Vieira; Eduardo N. dos Santos; Elena V. Gusevskaya

2009-01-01

259

Health promotion programs related to the Athens 2004 Olympic and Para Olympic games  

Microsoft Academic Search

BACKGROUND: The Olympic Games constitute a first-class opportunity to promote athleticism and health messages. Little is known, however on the impact of Olympic Games on the development of health-promotion programs for the general population. Our objective was to identify and describe the population-based health-promotion programs implemented in relation to the Athens 2004 Olympic and Para Olympic Games. METHODS: A cross-sectional

Elpidoforos S Soteriades; Christos Hadjichristodoulou; Jeni Kremastinou; Fotini C Chelvatzoglou; Panagiotis S Minogiannis; Matthew E Falagas

2006-01-01

260

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.

261

Ironía, nostalgia y deconstrucción en Canciones para después de una guerra  

Microsoft Academic Search

Canciones para después de una guerra (Martín\\u000aPatino, 1971) comprises an ironic archive documentary\\u000aabout Spain during the forties. Using different editing\\u000astrategies —such as re-location of materials, fusion between sound and image, figures of speech and montage effects—, the film proposes an alternative view to thedominant one offered by Franco’s official media. The movie provides a re-reading of the

Alberto Nahum García Martínez

2007-01-01

262

ParaDock: a flexible non-specific DNA--rigid protein docking algorithm  

PubMed Central

Accurate prediction of protein–DNA complexes could provide an important stepping stone towards a thorough comprehension of vital intracellular processes. Few attempts were made to tackle this issue, focusing on binding patch prediction, protein function classification and distance constraints-based docking. We introduce ParaDock: a novel ab initio protein–DNA docking algorithm. ParaDock combines short DNA fragments, which have been rigidly docked to the protein based on geometric complementarity, to create bent planar DNA molecules of arbitrary sequence. Our algorithm was tested on the bound and unbound targets of a protein–DNA benchmark comprised of 47 complexes. With neither addressing protein flexibility, nor applying any refinement procedure, CAPRI acceptable solutions were obtained among the 10 top ranked hypotheses in 83% of the bound complexes, and 70% of the unbound. Without requiring prior knowledge of DNA length and sequence, and within <2?h per target on a standard 2.0?GHz single processor CPU, ParaDock offers a fast ab initio docking solution.

Banitt, Itamar; Wolfson, Haim J.

2011-01-01

263

The rotational excitation of the interstellar HNC by para- and ortho-H2.  

PubMed

Rotational excitation of the interstellar HNC due to collisions with H(2) is investigated. We present a new four dimensional (4D) potential energy surface for the HNC-H(2) collisional system. Both molecules were treated as rigid rotors. Interaction energy was obtained from the electronic structure calculations using a single and double-excitation coupled cluster method with perturbative contributions from connected triple excitations [CCSD(T)]. The five atoms were described using the aug-cc-pVTZ basis sets. Bond functions were placed at mid-distance between the HNC center of mass and the center of mass of H(2) for a better description of the van der Waals interaction. Close coupling calculations of the inelastic integral cross sections of HNC in collisions with para-H(2) and ortho-H(2) were calculated for kinetic energies up to 800 cm(-1). After Boltzmann thermal averaging, rate coefficients were obtained for temperatures ranging from 5 to 100 K. Significant differences exist between para- and ortho-H(2) results. The strongest collision-induced rotational HNC transitions are the transitions with ?j = 1 for collisions with para-H(2) and with ortho-H(2). The new rate coefficients should induce important consequences on the determination of HNC abundance in the interstellar medium. In particular, we expect that they will help to solve the interstellar problem of relative abundance of the HCN and HNC isomers. PMID:21298130

Dumouchel, Fabien; K?os, Jacek; Lique, François

2011-02-04

264

Quantum chemical and experimental study of 1,2,4-trihydroxy-para-menthane  

NASA Astrophysics Data System (ADS)

The conformational analysis of the para-menthane (PM) and 1,2,4-trihydroxy-para-menthane (TPM) is performed using the quantum chemical density functional theory (DFT) and ab initio Møller-Plesset perturbation theory up to the second order (MP2). In TPM, three hydroxyl groups generate eight stereoisomers comparing to the four para-menthane stereoisomers. From the thermodynamics point of view, the most preferred conformations show the chair-shaped configuration of the cyclohexane ring. The obtained energy barriers for the isopropyl group rotation in the chair-shaped stereoisomers are between 35 and 45 kJ mol?1. The crystal structure as well as the solvated TPM stereoisomer isolated from the Tea tree oil, Melaleuca alternifolia (Maiden & Betche) Cheel, were investigated experimentally. Isolated stereoisomer corresponds to the most energetically preferred conformation and the calculated structural data agree very well with the results from the X-ray and nuclear magnetic resonance measurements. Finally, the influence of the conformation and the presence of the intramolecular hydrogen bonds on the homolytic OH bond dissociation enthalpies and proton affinities were also discussed with respect to the simple alcohols (methanol, iso-propanol, iso-pentanol, tert-butanol, cyclohexanol) and phenol.

Rottmannová, Lenka; Lukeš, Vladimír; Il?in, Michal; Fodran, Peter; Herich, Peter; Kožíšek, Jozef; Liptaj, Tibor; Klein, Erik

2013-10-01

265

Para-GMRF: parallel algorithm for anomaly detection of hyperspectral image  

NASA Astrophysics Data System (ADS)

The hyperspectral imager is capable of collecting hundreds of images corresponding to different wavelength channels for the observed area simultaneously, which make it possible to discriminate man-made objects from natural background. However, the price paid for the wealthy information is the enormous amounts of data, usually hundreds of Gigabytes per day. Turning the huge volume data into useful information and knowledge in real time is critical for geoscientists. In this paper, the proposed parallel Gaussian-Markov random field (Para-GMRF) anomaly detection algorithm is an attempt of applying parallel computing technology to solve the problem. Based on the locality of GMRF algorithm, we partition the 3-D hyperspectral image cube in spatial domain and distribute data blocks to multiple computers for concurrent detection. Meanwhile, to achieve load balance, a work pool scheduler is designed for task assignment. The Para-GMRF algorithm is organized in master-slave architecture, coded in C programming language using message passing interface (MPI) library and tested on a Beowulf cluster. Experimental results show that Para-GMRF algorithm successfully conquers the challenge and can be used in time sensitive areas, such as environmental monitoring and battlefield reconnaissance.

Dong, Chao; Zhao, Huijie; Li, Na; Wang, Wei

2007-11-01

266

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

267

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

PubMed Central

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.

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

2012-01-01

268

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

269

Enhanced mitigation of para-chlorophenol using stratified activated carbon adsorption columns.  

PubMed

The adsorptive removal of toxic para-chlorophenol using activated carbon adsorption columns is a proven effective engineering process. This paper examined the possibility to stratify an adsorbent bed into layers, in order to enhance the adsorption process performance in terms of increased column service time and adsorbent bed saturation. Four different types of fixed-bed adsorption columns are used and compared under the same operating conditions, but with the variation of column geometry and activated carbon particle size stratification. The Type 3 column - a cylindrical column with particle stratification packing, is found to be the most efficient choice, as the extent of column service time and adsorbent bed saturation are the largest. This could eventually decrease the frequency of adsorbent replacement/regeneration and hence reduce the operating cost of the fixed-bed adsorption process. The Homogeneous Surface Diffusion Model (HSDM) was applied successfully to describe the dynamic adsorption of para-chlorophenol onto Filtrasorb 400 (F400) activated carbon in different types of columns. The Redlich-Peterson isotherm model equation, an experimentally derived external mass transfer correlation and a constant surface diffusivity are used in the HSDM. The optimised surface diffusivity of para-chlorophenol is found to be 1.20E-8 cm(2)/s, which is in good agreement with other phenolics/F400 carbon diffusing systems in literature. PMID:22154109

Sze, Michael Fan Fu; McKay, Gordon

2011-11-19

270

Madres para la Salud: Design of a Theory-based Intervention for Postpartum Latinas  

PubMed Central

Background Weight gain in young women suggests that childbearing may be an important contributor to the development of obesity in women. Depressive symptoms can interfere with resumption of normal activity levels following childbirth or with the initiation of or adherence to physical activity programs essential for losing pregnancy weight. Depression symptoms may function directly to promote weight gain through a physiologic mechanism. Obesity and its related insulin resistance may contribute to depressed mood physiologically. Although physical activity has well-established beneficial effects on weight management and depression, women tend to under participate in physical activity during childbearing years. Further, the mechanisms underpinning the interplay of overweight, obesity, physical activity, depression, and inflammatory processes are not clearly explained. Objectives This report describes the theoretical rationale, design considerations, and cultural relevance for “Madres para la Salud” [Mothers for Health]. Design and Methods Madres para la Salud is a 12 month prospective, randomized controlled trial exploring the effectiveness of a culturally specific intervention using “bouts” of physical activity to effect changes in body fat, systemic and fat tissue inflammation, and postpartum depression symptoms in sedentary postpartum Latinas. Summary The significance and innovation of Madres para la Salud includes use of a theory-driven approach to intervention, specification and cultural relevance of a social support intervention, use of a Promotora model to incorporate cultural approaches, use of objective measures of physical activity in post partum Latinas women, and the examination of biomarkers indicative of cardiovascular risk related to physical activity behaviors in postpartum Latinas.

Keller, Colleen; Records, Kathie; Ainsworth, Barbara; Belyea, Michael; Permana, Paska; Coonrod, Dean; Vega-Lopez, Sonia; Nagle-Williams, Allison

2011-01-01

271

Dysregulated expression of HOX and ParaHOX genes in human esophageal squamous cell carcinoma.  

PubMed

Homeobox genes function as master regulators in embryonic morphogenesis. We hypothesized that homeobox genes are essential to maintain tissue- or organ-specificity even in adult body and that the dysregulated expression of homeobox genes results in tumor development and progression. To better understand the roles of homeobox genes in development and progression of esophageal cancer, we analyzed the expression patterns of 39 HOX genes and 4 ParaHOX (CDX1, CDX2, CDX4 and PDX1) genes in esophageal squamous cell carcinoma (ESCC) and normal esophageal mucosa tissues. A total of 48 primary ESCC tissues and 7 normal esophageal mucosa tissues were resected from patients who underwent radical surgery without any preoperative chemotherapy or radiotherapy. The expression of HOX and ParaHOX genes were analyzed by a quantitative real-time RT-PCR method and immunohistochemistry. The expression levels of 24 HOX genes, CDX1, CDX2 and PDX1 were significantly higher in ESCC compared to normal mucosa (p<0.01, Mann-Whitney U test). The Immunohistochemical study revealed that HOXA5 and D9 proteins were more cytoplasmic in ESCC than normal mucosa cells. Our data indicate that the disordered expression of HOX and ParaHOX genes are involved in the development of ESCC or its malignancy. PMID:17342311

Takahashi, Osamu; Hamada, Jun-Ichi; Abe, Motoki; Hata, Shinya; Asano, Toshimichi; Takahashi, Yoko; Tada, Mitsuhiro; Miyamoto, Masaki; Kondo, Satoshi; Moriuchi, Tetsuya

2007-04-01

272

Theoretical and Experimental Study of the Infrared Spectra of CO_2-(para-H_2)_2 Trimers  

NASA Astrophysics Data System (ADS)

The infrared spectra of several isotopologues of the CO_2-(para-H_2)_2 trimer have been predicted by applying exact basis-set calculations to a global potential energy surface which is defined as a sum of the accurately known two-body para-H_2--CO_2 and para-H_2--para-H_2 potentials. These results are compared with new spectroscopic measurements, for which sixteen transitions have been assigned. A reduced-dimension treatment of the para-H_2 rotation has been employed by performing an exact hindered-rotor average. Three-body effects and the quality of the potential are discussed. We present a new technique for representing the three-dimensional para-H_2 density in the body-fixed frame. It shown the two para-H_2 molecules are localized much more closely together than is the case for the two He atoms in the analogous CO_2--(He)_2 system. H. Li, P.-N. Roy and R.J. Le Roy, J. Chem. Phys. (2010, submitted); K. Patkowski, W. Cencek, P. Jankowski, K. Szalewicz, J.B. Mehl, G. Garberoglio and A.H. Harvey, J. Chem. Phys. 129, 094304 (2010). H. Li, P.-N. Roy and R.J. Le Roy, J. Chem. Phys. (2010 submitted).

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

2010-06-01

273

A sensitive and selective enzyme-linked immunosorbent assay for the analysis of Para red in foods.  

PubMed

Para red is a synthetic dye and a potential genotoxic carcinogen. A hapten mimicking Para red structure was synthesized by introducing a carboxyl to the naphthol part of Para red and coupled to carrier protein to form an immunogen for the production of specific antibodies. A sensitive and selective enzyme-linked immunosorbent assay (ELISA) was developed for the detection of Para red in food samples. The limit of detection and inhibition half-maximum concentrations of Para red in phosphate buffered saline with 10% methanol were 0.06 and 2.2 ng mL(-1), respectively. Cross-reactivity values of the ELISA with the tested compounds including Sudan red I, II, III, IV, and G, sunset yellow, 2-naphthol, and 4-nitroaniline were ?0.2%. This assay was used to determine Para red in tomato sauce, chilli sauce, chilli powder and sausage samples after ultrasonic extraction, cleanup and concentration steps. The average recoveries, repeatability (intraday extractions and analysis), and intra-laboratory reproducibility (interday extractions and analysis) were in the range 90-108%, 4-12% and 8-17%, respectively. This assay was compared to a high-performance liquid chromatographic method for 28 samples, displaying a good correlation (R(2) = 0.95). Para red residues in 53 real world samples determined by ELISA were below the limit of detection. PMID:22439137

Wang, Jia; Wei, Keyi; Li, Hao; Li, Qing X; Li, Ji; Xu, Ting

2012-03-21

274

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

275

ParaDyn Implementation in the US Navy's DYSMAS Simulation System: FY08 Progress Report  

SciTech Connect

The goal of this project is to increase the computational efficiency and capacity of the Navy's DYSMAS simulation system for full ship shock response to underwater explosion. Specifically, this project initiates migration to a parallel processing capability for the structural portion of the overall fluid-structure interaction model. The capstone objective for the first phase is to demonstrate operation of the DYSMAS simulation engine with a production model on a Naval Surface Warfare Center (IHD) parallel platform using the ParaDyn code for parallel processing of the structural dynamics. This year saw a successful launch to integrate ParaDyn, the high-parallel structural dynamics code from Lawrence Livermore National Laboratory (LLNL), into the DYSMAS system for simulating the response of ship structures to underwater explosion (UNDEX). The current LLNL version of DYNA3D, representing ten years of general development beyond the source branch used to initiate DYNA-N customization for DYSMAS, was first connected to the GEMINI flow code through DYSMAS Standard Coupler Interface (SCI). This permitted an early 'sanity check' by Naval Surface Warfare Center, Indian Head Division (NSWC-IHD) personnel that equivalent results were generated for their standard UNDEX test problems, thus ensuring the Verification & Validation pedigree they have developed remains intact. The ParaDyn code was then joined to the SCI in a manner requiring no changes to GEMINI. Three NSWC-IHD engineers were twice hosted at LLNL to become familiar with LLNL computer systems, the execution of the prototype software system, and to begin assessment of its accuracy and performance. Scaling data for the flow solver GEMINI was attained up to a one billion cell, 1000 processor run. The NSWC-IHD engineers were granted privileges to continue their evaluations through remote connections to LLNL's Open Computing Facility. Finally, the prototype changes were integrated into the mainline ParaDyn source repository and issued as part of its Version 8.1 beta release. This source was transmitted to NSWC-IHD and in collaboration with LLNL personnel the entire ParaDyn software suite successfully installed and demonstrated on its new SGI Altix machine. The ability of even minor numbers of processors for the structural dynamics to impact overall time-to-solution for DYSMAS has been demonstrated. Assessments of combined parallel efficiencies are beginning to highlight areas for further DYSMAS optimizations.

Ferencz, R M; DeGroot, A J; Lin, J I; Zywicz, E; Durrenberger, J K; Sherwood, R J; Corey, I R

2008-07-29

276

A single amino acid change in the para sodium channel protein is associated with knockdown-resistance ( kdr) to pyrethroid insecticides in German cockroach  

Microsoft Academic Search

Previous genetic and pharmacological studies suggest that knockdown-resistance (kdr) to pyrethroid insecticides likely results from a mutation(s) in the para sodium channel gene. In this study, para sodium channel genes from an insecticide-susceptible German cockroach strain, CSMA, and a kdr-type German cockroach strain, Ectiban-R, were cloned and sequenced. Comparison of the nucleotide sequences of paraCSMA and paraEctiban-R revealed two nucleotide

Ke Dong

1997-01-01

277

75 FR 34943 - Defense Federal Acquisition Regulation Supplement; Para-Aramid Fibers and Yarns Manufactured in a...  

Federal Register 2010, 2011, 2012, 2013

...Under Secretary of Defense for Acquisition, Technology, and Logistics with regard to the acquisition of items containing para-aramid...the textile manufacturing that remains has moved into high performance and niche specialty areas. This respondent stated that...

2010-06-21

278

Unique para-effect in electron ionization mass spectra of bis(perfluoroacyl) derivatives of bifunctional aminobenzenes.  

PubMed

A new kind of 'para-effect' under electron ionization (EI) conditions has been discovered for a series of bis(perfluoroacyl) derivatives of o-, m- and p-phenylenediamines, -hydroxybenzeneamines and -mercaptobenzeneamines of a common structure RCOX-C(6)H(4)-NHCOR (X = NH, S, O; R = CF(3), C(2)F(5), C(3)F(7)). Only the para-isomers showed successive loss of a radical RCO* and a molecule RCN, leading to very intense peaks in the EI spectra. The composition and the origin of the [M-COR-NCR](+) ions were confirmed by exact mass measurements and linked scan experiments. The proposed mechanism of their formation takes into account likely para-quinoid structures of the precursor ions. A similar rearrangement has not been observed for para-isomers in the series of bis(perfluoroacyl) derivatives of benzenediols, mercaptophenols and dimercaptobenzenes. PMID:20740526

Tretyakov, Kirill V; Todua, Nino G; Borisov, Roman S; Zaikin, Vladimir G; Stein, Stephen E; Mikaia, Anzor I

2010-09-15

279

Pressure induced phase transitions in pentacene doped para-terphenyl probed by changes in the impurity absorption spectrum  

Microsoft Academic Search

The pressure dependence (0–10 kbar) of the low temperature (15 K) absorption spectrum of pentacene impurities in a para-terphenyl host crystal is used to investigate the pressure and\\/or temperature induced triclinic to monoclinic phase change of the para-terphenyl host crystal. Due to the characteristic absorption spectrum of pentacene in these two crystal phases, the pentacene impurity proves to be a

Bruce J. Baer; Eric L. Chronister

1993-01-01

280

The effect of pressure on the fluorescence lifetime of pentacene in para-terphenyl at low temperature  

Microsoft Academic Search

Time resolved fluorescence measurements are presented as a function of pressure for pentacene in para-terphenyl at low temperature. A photosite specific pressure effect is observed at low temperature for the triclinic (P?5.5 kbar) phase of para-terphenyl. In addition, the fluorescence lifetime of pentacene in the monoclinic (high pressure) crystal phase at low temperature is obtained. We also observe unique fluorescence

Bruce J. Baer; Eric L. Chronister

1994-01-01

281

The Use of Para-Aminobenzoic Acid (PABA) as a Compliance Measure for Large, Long-Term Feeding Studies  

Microsoft Academic Search

LEARNING OUTCOME: To analyze the use of para-aminobenzoic acid for large long-term feeding studies as a measure of compliance.Metabolic diets are precisely designed to meet each feeding studies’ unique protocol. Valid results are solely dependent upon the total consumption of each prescribed diet. Therefore, compliance is a major concern. Para-aminobenzoic acid (PABA) is a non-metabolized marker that can be incorporated

M. L. Barkate; M. M. Windhauser; F. M. Ramezanzadeh; S. Richard; R. Tulley

1997-01-01

282

Fabrication and electro chemical properties of poly vinyl alcohol\\/para toluene sulfonic acid membranes for the applications of DMFC  

Microsoft Academic Search

The novel acid–base membranes composed of para toluene sulfonic acid (pTSA) as an acidic compound, and poly vinyl alcohol (PVA) as a basic compound were fabricated. The morphological and structural properties of the prepared membranes were analyzed by scanning electron microscopy and Infra red spectroscopy. Inclusion of Glutaraldehyde (GLA) and para toluene sulfonic acid (pTSA) promotes the amorphous character of

G. Gnana Kumar; Periyayya Uthirakumar; Kee Suk Nahm; R. Nimma Elizabeth

2009-01-01

283

Point mutations in the Drosophila sodium channel gene para associated with resistance to DDT and pyrethroid insecticides  

Microsoft Academic Search

The gene para in Drosophila melanogaster encodes an ? subunit of voltage-activated sodium channels, the presumed site of action of DDT and pyrethroid insecticides.\\u000a We used an existing collection of Drosophila para mutants to examine the molecular basis of target-site resistance to pyrethroids and DDT. Six out of thirteen mutants tested\\u000a were associated with a largely dominant, 10- to 30-fold

B. Pittendrigh; R. Reenan; R. H. ffrench-Constant; B. Ganetzky

1997-01-01

284

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

285

Local and official forms of symbolic control: an Australian case study of the pedagogic work of para-educational personnel  

Microsoft Academic Search

In this paper an analysis is undertaken of the accounts of pedagogic work provided by para-educational personnel working in two government-funded schools situated in a low socio-economic area of an Australian city. Specifically, the paper examines the accounts of two para-educational personnel who identified as Samoan\\/Pacific Islander and worked to improve the educational outcomes of students from the local Samoan\\/Pacific

Parlo Singh

2000-01-01

286

Costruzioine dell'Area Europea della Ricerca in biomedicina e Contributo Degli enti di Ricerca del Servizio Sanitario Nazionale (Building the European Research Area in Biomedicine and the Contribution of the Research Institutions of the National Health Service).  

National Technical Information Service (NTIS)

The Lisbon Strategy aims at making the European Union the most dynamic and competitive knowledge-based economy and the building the European Research Area (ERA) represents one of its fundamental elements. The launch of the 7th framework program, specifica...

F. Belardelli F. D'Alessandro M. Ferrantini

2007-01-01

287

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

288

ParaSight-F rapid manual diagnostic test of Plasmodium falciparum infection.  

PubMed

The ParaSight(R)-F test is a qualitative diagnostic test of Plasmodium falciparum, which is based on the detection by a monoclonal antibody of a species-specific soluble antigen (histidine-rich protein (HRP-II)) in whole blood and which can be performed without special equipment. A visual reading is given by a polyclonal antibody coupled with dye-loaded liposomes; when positive, a pink line appears. The test has been compared with microscopic examination of thin blood smears and with Quantitative Buffy Coat malaria test (QBC(R) in a single-blind study. A total of 358 patients who had returned to France from malarial areas and consulted their doctor with symptoms or for a routine examination were enrolled in the study; 33 of them were found to have a falciparum malaria infection by the diagnostic test. On the day of consultation, the specificity of the ParaSight(R)-F test was 99% and its sensitivity 94%. The follow-up of infected patients after treatment showed that the test became negative later than the other reference tests. There was no correlation between antigen persistence and the intensity of the ParaSight(R)-F signal or circulating parasitaemia. No cross-reaction was noted for seven malaria cases due to other Plasmodium species. The test was performed quickly (10 tests in 20 minutes), was easy to read, and required minimal space. For cases of imported malaria, the test's specificity and low threshold for detection could make it a valuable adjunct test. However, in its present form, it cannot replace microscopic techniques which are species-specific and quantitative. In endemic areas, the test seems to be very promising by its results and ease of use according to published field studies. PMID:8846490

Uguen, C; Rabodonirina, M; De Pina, J J; Vigier, J P; Martet, G; Maret, M; Peyron, F

1995-01-01

289

Haze, Methane And Para-hydrogen Distributions On Uranus And Neptune  

NASA Astrophysics Data System (ADS)

The distribution of aerosols, methane, and molecular hydrogen-para fraction on Uranus and Neptune are investigated from spatially resolved near-IR spectra. For reasons not yet understood, Neptune is one of the most meteorologically active planets in the solar system. Uranus, which appeared relatively featureless in Voyager 2 images, has shown increased activity in recent years [1], presumably revealing seasonal changes. The advent of the HST and adaptive optics technology has allowed researchers to map clouds and retrieve chemical abundances [2,3], providing clues to the dynamics driving these worlds. For this study, latitude resolved H- and K-band spectra and images were obtained using adaptive optics on the 200” Hale telescope at the Palomar Observatory. Data was acquired nearly annually from 1999 to 2007, with several longitudes covered each year. We use an objective, systematic retrieval algorithm (using singular value decomposition) to minimize differences between observed and modeled spectra. Best fitting vertical profiles of aerosol and methane abundance are retrieved, along with the molecular hydrogen para-fraction. Most observations suggest two layers of aerosols, with a stratospheric depletion of methane, and roughly equilibrium para-fractions, each varying with latitude. These parameters are tracers of atmospheric motions and can provide insight into the atmospheric circulations. Variations in latitude suggest regions of stronger upwelling while temporal changes suggest seasonal change. This project was funded under the NASA Outer Planets Research program. [1] Rages, K.A., H.B. Hammel and A.J. Friedson, 2004. Evidence for temporal change at Uranus’ south pole. Icarus, 172, 548-554. [2] Sromovsky, L.A. and P.M.Fry, 2008. The methane abundance and structure of Uranus’ cloud bands inferred from spatially resolved 2006 Keck grism spectra. Icarus, 193, 252-266 [3] Karkoschka, E., 2011. Neptune’s cloud and haze variations 1994-2008 from 500 HST-WFPC2 images. Icarus 215. 759-773.

Roman, Michael; Banfield, D.; Gierasch, P. J.; Stam, D. M.

2012-10-01

290

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

291

Ortho/Para Ratio of H2O+ Toward Sagittarius B2(M) Revisited  

NASA Astrophysics Data System (ADS)

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.

Schilke, Peter; Lis, Dariusz C.; Bergin, Edwin A.; Higgins, Ronan; Comito, Claudia

2013-10-01

292

Diophantine properties of the zeros of certain Laguerre and para-Jacobi polynomials  

NASA Astrophysics Data System (ADS)

Matrices \\underline{A} and \\underline{B} of arbitrary rank N, given by simple expressions in terms of the N zeros of certain Laguerre or para-Jacobi polynomials of degree N, feature a Diophantine property. In the Laguerre case, this property states that the 2N zeros of the polynomial p_{2N}\\left( \\lambda \\right) =\\det \\left[ \\lambda ^{2}+\\lambda \\underline{A} +\\underline{B}\\right] are all integers; indeed we conjecture that \\det \\left[ \\lambda ^{2}+\\lambda \\underline{A}+\\underline{B}\\right] =\\prod \

Calogero, Francesco; Yi, Ge

2012-03-01

293

First order optical nonlinearities ? for organic nanofibers from functionalized para-phenylenes  

NASA Astrophysics Data System (ADS)

Optical frequency doubling is demonstrated from nanoscaled, parallely oriented needle-like organic aggregates (‘nanofibers’) that have been grown on mica surfaces from unsymmetrically functionalized para-quaterphenylene organic molecules. Wavelength dependent absolute values of the first order non-linear susceptibility, ?zzz(2), are measured for nanofibers from six differently functionalized molecules. These quantitative measurements are enabled by combining relative second-harmonic intensity measurements with reference to a quartz crystal with morphological information on the individual nanoaggregates gathered from atomic force microscopy images. Values up to that of KDP(d36) are found for nanofibers from specific functionalized molecules.

Brewer, J.; Schiek, M.; Wallmann, I.; Rubahn, H.-G.

2008-07-01

294

Low-threshold blue lasing in epitaxially grown para-sexiphenyl nanofibers  

Microsoft Academic Search

Random laser action and amplified spontaneous emission are observed near 425nm in self-assembled para-sexiphenyl nanofibers following subpicosecond optical pumping. The threshold excitation fluence (photoexcited density) is as low as 0.5?J\\/cm2 (6×1016cm?3). The high degree of material crystallinity results in a very large singlet–singlet annihilation rate of ?10?7cm3\\/s. In stationary conditions, assuming a standard singlet-to-triplet density ratio of 0.3 and bimolecular

F. Quochi; A. Andreev; F. Cordella; R. Orru; A. Mura; G. Bongiovanni; H. Sitterb Hoppe; H. Sitter; N. S. Sariciftci

2005-01-01

295

The Ortho:Para Ratio of H3+ in Diffuse Molecular Clouds  

NASA Astrophysics Data System (ADS)

Since its first interstellar detection in the mid 1990s, H3+ has proved to be a powerful probe of astrophysical conditions. In cold molecular clouds, only the lowest two rotational energy levels of H3+ are populated: the (J,K) = (1,1) para state and the (1,0) ortho state. The relative populations of these levels can be used to calculate an excitation temperature, Tex. In dense molecular clouds, Tex agrees well with the estimated cloud kinetic temperature. However, in diffuse molecular clouds, Tex is found to be 30 K, while the kinetic temperature, as determined from the excitation temperature T01 (given by the relative populations of the J = 0 and J = 1 rotational levels of H2) is on average 60-70 K in these environments. Because the (1,1) state of H3+ is the lower-energy state, this indicates that there is more para-H3+ in diffuse molecular clouds than would be expected based on the cloud kinetic temperature. To understand the excess para-H3+ (or the lower-than-expected Tex), we have constructed a chemical model that takes into account the nuclear spin dependence of H3+ formation, proton scrambling via collisions with H2, and dissociative recombination with electrons. At the heart of this model is the reaction H3+ + H2 ? H2 + H3+ , which can proceed by one of three pathways: the identity, proton hop, and hydrogen exchange. The branching fractions for the three pathways, Sid, Shop, and Sexch, influence the nature and extent of the proton scrambling. We use the microcanonical statistical model of Park and Light (J. Chem. Phys. 126, 044305, 1997) to calculate nuclear-spin-dependent rate coefficients that describe the extent of proton scrambling as a function of temperature and the aforementioned branching fractions. As a result, our model predicts, based on these parameters, what the observed Tex should be for a certain cloud kinetic temperature. Our model suggests that on its own, the H3+ + H2 reaction would effectively thermalize the ortho:para H3+ ratio (i.e., Tex = T01). However, dissociative recombination is taken into account, this thermalization is incomplete, and the resultant competition between thermalization and dissociative recombination seems to reproduce the astronomical observations for Sid ~ 0.8-0.9. However, the details of the spin-dependence of H3+ dissociative recombination are important, and at present, experimentally uncertain. More information about this process is needed to determine the validity of our modeling results.

Crabtree, Kyle N.; Indriolo, Nick; Kreckel, Holder; Tom, Brian A.; McCall, Benjamin J.

2010-11-01

296

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

297

On linear differential equations with variable coefficients involving a para-Grassmann variable  

NASA Astrophysics Data System (ADS)

Linear differential equations with constant coefficients involving a para-Grassmann variable have been considered recently in the work of Mansour and Schork [Symmetry, Integr. Geom.: Methods Appl. 5, 73 (2009)]. In the present paper, this treatment is extended to linear differential equations with variable coefficients. For the equation of first order, an explicit formula for the solution is given. For the equations of higher order, it is shown how the solutions may be determined in terms of the solutions of ``ordinary'' differential equations (i.e., involving only ``bosonic'' variables). Some examples of these differential equations are discussed and analogs for the trigonometric functions are introduced.

Mansour, Toufik; Schork, Matthias

2010-04-01

298

Electron delocalization in CrII complexes checked by ortho- into para-positronium conversion reactions  

NASA Astrophysics Data System (ADS)

The metal electron delocalization caused by ligands in 3d complexes may be evaluated by means of the empirical equation ?=1-tMhL where tM and hL are constants depending on metal ion and ligand types, respectively. tM and hL are till now derived by UV-VIS absorption spectroscopy. By applying a completely different approach, i.e. the correlation found between ? and the rate constants of the ortho- into para-positronium spin conversion reactions, the tM value of CrII was determined and that of NiII checked.

Lazzarini, A. L. F.; Lazzarini, E.; Mariani, M.

1999-03-01

299

Para-aminosalicylic acid-induced hypoglycaemia in a patient with diabetic nephropathy.  

PubMed

A 62-year-old Indian with diabetic nephropathy controlled with metformin, developed miliary tuberculosis for which he was treated with rifampicin, isoniazid and ethambutol. Soon afterwards he developed cholestatic hepatitis and visual disturbance. Rifampicin and ethambutol were stopped. Streptomycin caused vertigo and had to be stopped. The introduction of para-aminosalicylic acid (PAS) led to hypoglycaemic coma. Metformin was stopped. Hypoglycaemic coma recurred. PAS was stopped and the patient's blood glucose concentrations became normal. Treatment with isoniazid and ethambutol led to total recovery from pulmonary tuberculosis. The induction of hypoglycaemia with PAS in this patient suggests a potential role for PAS in the treatment of diabetes mellitus. PMID:7393795

Dandona, P; Greenbury, E; Beckett, A G

1980-02-01

300

Para-aminosalicylic acid-induced hypoglycaemia in a patient with diabetic nephropathy.  

PubMed Central

A 62-year-old Indian with diabetic nephropathy controlled with metformin, developed miliary tuberculosis for which he was treated with rifampicin, isoniazid and ethambutol. Soon afterwards he developed cholestatic hepatitis and visual disturbance. Rifampicin and ethambutol were stopped. Streptomycin caused vertigo and had to be stopped. The introduction of para-aminosalicylic acid (PAS) led to hypoglycaemic coma. Metformin was stopped. Hypoglycaemic coma recurred. PAS was stopped and the patient's blood glucose concentrations became normal. Treatment with isoniazid and ethambutol led to total recovery from pulmonary tuberculosis. The induction of hypoglycaemia with PAS in this patient suggests a potential role for PAS in the treatment of diabetes mellitus.

Dandona, P.; Greenbury, E.; Beckett, A. G.

1980-01-01

301

Experimental and theoretical investigation of 5-para-nitro-benzylidene-thiazolidine-2-thione-4-one molecule  

Microsoft Academic Search

Experimental methods (FT-IR, Raman and NMR spectroscopies, and X-ray diffraction technique) coupled with quantum chemical calculations based on density functional theory (DFT) are used for structural and electronic characterization of 5-para-nitro-benzylidene-thiazolidine-2-thione-4-one (5pN-BTT).X-ray diffraction technique indicates that this compound crystallizes with one tetrahydrofuran (THF) solvent molecule, forming a 1:1 5pN-BTT·THF complex, in the monoclinic space group C2\\/c, with Z=8 and cell

Adrian Pîrnau; Vasile Chis; Laszlo Szabo; Onuc Cozar; Mihai Vasilescu; Ovidiu Oniga; Richard A. Varga

2009-01-01

302

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

303

Photoisomerization of the green fluorescence protein chromophore and the meta- and para-amino analogues.  

PubMed

The Z --> E photoisomerization and fluorescence quantum yields for the wild-type green fluorescence protein (GFP) chromophore (p-HBDI) and its meta- and para-amino analogues (m-ABDI and p-ABDI) in aprotic solvents (hexane, THF, and acetonitrile) and protic solvents (methanol and 10-20% H(2)O in THF) are reported. The dramatic decrease in the quantum yields on going from aprotic to protic solvents indicates the important role of solvent-solute hydrogen bonding in the nonradiative decay pathways. The enhanced fluorescence of m-ABDI is also discussed. PMID:18389128

Yang, Jye-Shane; Huang, Guan-Jhih; Liu, Yi-Hung; Peng, Shie-Ming

2008-01-18

304

Molecular dynamics simulations of the growth of poly(chloro-para-xylylene) films.  

PubMed

Parylene C, poly(chloro-para-xylylene) is the most widely used member of the parylene family due to its excellent chemical and physical properties. In this work we analyzed the formation of the parylene C film using molecular mechanics and molecular dynamics methods. A five unit chain is necessary to create a stable hydrophobic cluster and to adhere to a covered surface. Two scenarios were deemed to take place. The obtained results are consistent with a polymer film scaling growth mechanism and contribute to the description of the dynamic growth of the parylene C polymer. PMID:21547549

Gieldon, Artur; Czaplewski, Cezary; Smalara, Krzysztof; Bobrowski, Maciej

2011-05-06

305

Frequency-dependent polarizability of —CC— linked para-nitroaniline monomer through pentamer  

NASA Astrophysics Data System (ADS)

Using atomic orbital basis sets calibrated in an earlier study on the monomer and dimer and employing the direct atomic-integral driven strategy of the DISCO program package, we performed self-consistent field level calculations of the frequency-dependent polarizabilities of the monomer through pentamer of —CC— linked para-nitroaniline. These computations, which were performed in parallel using seven IBM RS6000 model 560 workstations, involved up to 612 atomic basis functions and 10 11 two-electron integrals, and required solution of linear response equations whose dimensions ranged up to 132000.

Nichols, Jeff; Simons, Jack

1993-07-01

306

Para-hyoid ectopic parathyroid adenoma localized by Tc-99m MIBI SPECT.  

PubMed

A 64-year-old woman with a history of I-131 ablation for Graves hyperthyroidism and bilateral parathyroid exploration with resection of a left inferior parathyroid adenoma presented 2 years after surgery with marked fatigue, irritability, and joint pain. Laboratory testing revealed an elevated calcium and parathyroid hormone levels suspicious for hyperparathyroidism. The ultrasound indicated no evidence of a parathyroid adenoma. Tc-99m-MIBI SPECT demonstrated a focus of uptake posteroinferior to the right submandibular gland, suspicious for a parathyroid adenoma. Repeat ultrasound and CT confirmed the presence of a para-hyoid adenoma inferior to the right submandibular gland. PMID:19033797

Rajagopalan, Malolan S; Narla, Vinod V; Kanderi, Tanuja; Muthukrishnan, Ashok

2008-12-01

307

Asymmetric Top Rotors in Superfluid Para-Hydrogen Nano-Clusters  

NASA Astrophysics Data System (ADS)

We present the first simulation study of bosonic clusters doped with an asymmetric top molecule. A variation of the path-integral Monte Carlo method is developed to study a para-water (pH_2O) impurity in para-hydrogen (pH_2) clusters. The growth pattern of the doped clusters is similar in nature to that of the pure clusters. The pH_2O molecule appears to rotate freely in the cluster due to its large rotational constants and the lack of adiabatic following. The presence of pH_2O substantially quenches the superfluid response of pH_2 with respect to the space fixed frame. We also study the behaviour of a sulphur dioxide (32S16O_2) dopant in the pH_2 clusters. For such a heavy rotor, the adiabatic following of the pH_2 molecules is established and the superfluid renormalization of the rotational constants is observed. The rotational structure of the SO_2-p(H_2)_N clusters' ro-vibrational spectra is predicted. The connection between the superfluid response respect to the external boundary rotation and the dopant rotation is discussed.

Zeng, Tao; Li, Hui; Roy, Pierre-Nicholas

2012-06-01

308

Ortho-Para Conversion in Collisions of H2 with H2  

NASA Astrophysics Data System (ADS)

Molecular hydrogen is the main constituent of the atmospheres of the gas giant planets, Jupiter, Saturn, Uranus, and Neptune. The relative abundances of ortho- and parahydrogen are inferred from infrared spectra of the S(1) and S(0) quadrupole transitions near 17 and 28 microns, which sample conditions in the stratosphere and upper troposphere [1,2]. At most altitudes and latitudes the ortho/para ratio is not in statistical equilibrium at the local temperature, which is interpreted as resulting from vertical transport from lower hotter regions. In order to make inferences about atmospheric circulation we need reliable information about the rate of ortho-para conversion. Atmospheric modelers estimate that it takes 30 to 100 years [1,2]. The two candidate mechanisms are collisions with paramagnetic aerosols and with weak magnetic moment of ortho-H2. The better known mechanisms involving ions or H atoms are inoperative at the relevant low altitudes and low temperatures. Here we review the available information and conclude that magnetic interactions between hydrogen molecules will lead to interconversion in only about 5 years. We also outline theoretical procedures for quantum coupled channels calculations. [1] B. J. Conrath and P. J. Gierasch, Icarus 57, 184 (1984). [2] T. Fouchet, E. Lellouch, and H. Feuchtgruber, Icarus 161, 127 (2003).

Huestis, D. L.

2003-05-01

309

The ortho : para ratio of H3+ in laboratory and astrophysical plasmas.  

PubMed

In diffuse molecular clouds, the nuclear spin temperature of H(3)(+) (approx. 30?K) is much lower than the cloud kinetic temperature (approx. 70?K). To understand this temperature discrepancy, we have measured the ratio of the hop to exchange pathways (?) in the H(3)(+) + H(2) --> H(2) + H(3)(+) reaction (which interconverts ortho- and para-H(3)(+)) using high-resolution spectroscopy of the ?(2) fundamental band of H(3)(+) in a hydrogenic plasma. We find that ? decreases from 1.6±0.1 at 350?K to its statistical value of 0.5±0.1 at 135?K. We use this result to model the steady-state chemistry of diffuse molecular clouds, finding good agreement with astronomical data provided the dissociative recombination rates of ortho- and para-H(3)(+) are equal and the identity branching fraction for the H(3)(+) + H(2) reaction is large. Our results highlight the need for further studies of the H(3)(+) + H(2) reaction as well as state-selective measurements of H(3)(+) dissociative recombination. PMID:23028153

Crabtree, Kyle N; McCall, Benjamin J

2012-11-13

310

The rapid manual ParaSight-F test. A new diagnostic tool for Plasmodium falciparum infection.  

PubMed

A rapid manual test for Plasmodium falciparum, the ParaSight-F test, has been used on a series of patients in a holoendemic malaria area of coastal Tanzania. The test, which is an antigen capture test detecting trophozoite-derived histidine rich protein-II, is simple to perform and provides a definitive answer in about 10 min. It requires no special equipment and is read using a single drop of blood. When compared with 272 thick blood films examined microscopically by 2 observers and confirmed by the QBC malaria test, the ParaSight-F test had 88.9% sensitivity and 87.5% specificity. Detectable antigenaemia in a group of 40 people declined following treatment with Fansidar and by 10 d after treatment all but 4 individuals were antigen free. The remaining 4, although clear of peripheral parasitaemia, remained antigenaemic for 14 d. The test shows great promise for rapid effective diagnosis of P. falciparum in clinics and village health centres where there is no facility for microscopy. Because of its accuracy and rapid action it may even obviate the need for microscopical examination of blood films to diagnose P. falciparum malaria. PMID:8296363

Shiff, C J; Premji, Z; Minjas, J N

311

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

2013-05-22

312

The NiCEST approach: nickel(II) paraCEST MRI contrast agents.  

PubMed

Paramagnetic Ni(II) complexes are shown here to form paraCEST MRI contrast agents (paraCEST = paramagnetic chemical exchange saturation transfer; NiCEST = Ni(II) based CEST agents). Three azamacrocycles with amide pendent groups bind Ni(II) to form stable NiCEST contrast agents including 1,4,7-tris(carbamoylmethyl)-1,4,7-triazacyclononane (L1), 1,4,8,11-tetrakis(carbamoylmethyl)-1,4,8,11-tetraazacyclotetradecane (L2), and 7,13-bis(carbamoylmethyl)-1,4,10-trioxa-7,13-diazacyclopentadecane (L3). [Ni(L3)](2+), [Ni(L1)](2+), and [Ni(L2)](2+) have CEST peaks attributed to amide protons that are shifted 72, 76, and 76 ppm from the bulk water resonance, respectively. Both CEST MR images and CEST spectroscopy show that [Ni(L3)](2+) has the largest CEST effect in 100 mM NaCl, 20 mM HEPES pH 7.4 at 37 °C. This larger CEST effect is attributed to the sharper proton resonances of the complex which arise from a rigid structure and low relaxivity. PMID:23102112

Olatunde, Abiola O; Dorazio, Sarina J; Spernyak, Joseph A; Morrow, Janet R

2012-11-02

313

Theoretical study of the preferential solvation effect on the solvatochromic shifts of para-nitroaniline.  

PubMed

The origin of the nonlinear solvatochromic shift of para-nitroaniline was investigated using a mean-field sequential QM/MM method, with electron transitions computed at the CASPT2/cc-pVDZ level. Experimental data shows that the solvatochromic shift has a strong nonlinear behavior in certain solvent mixtures. We studied the case of cyclohexane-triethylamine mixtures. The results are in good agreement with the experiments and correctly reproduce the nonlinear variation of the solvent shift. Preferential solvation is clearly observed, where the local solvent composition in the neighborhood of the solute is significantly different from the bulk. It is found that even at low triethylamine concentrations a strong hydrogen bond is formed between para-nitroaniline and triethylamine, and cyclohexane is practically absent from the first solvation layer already at a molar fraction of 0.6 in triethylamine. The hydrogen bond formed is sufficiently long-lived to determine an asymmetric environment around the solute molecule. The resulting nonlinear solvent effect is mainly due to this hydrogen bond influence, although there is also a small contribution from dielectric enrichment. PMID:23343382

Frutos-Puerto, Samuel; Aguilar, Manuel A; Fdez Galván, Ignacio

2013-02-13

314

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

2013-06-03

315

Construction and characterization of two recombinant bacteria that grow on ortho- and para-substituted chlorobiphenyls  

SciTech Connect

Cloning and expression of the aromatic ring dehalogenation genes in biphenyl-growing, polychlorinated biphenyl (PCB)-cometabolizing Comamonas testosteroni VP44 resulted in recombinant pathways allowing growth on ortho- and para-chlorobiphenyls (CBs) as a sole carbon source. The recombinant variants were constructed by transformation of strain VP44 with plasmids carrying specific genes for dehalogenation of chlorobenzoates (CBAs). Plasmid pE43 carries the Pseudomonas aeruginosa 142 ohb genes coding for the terminal oxygenase (ISP{sub OHB}) of the ortho-halobenzoate 1,2-dioxygenase, whereas plasmid pPC3 contains the Arthrobacter globiformis KZT1 fcb genes, which catalyze the hydrolytic para-dechlorination of 4-CBA. The parental strain, VP44, grew only on low concentrations of 2- and 4-CB by using the products from the fission of the nonchlorinated ring of the CBs (pentadiene) and accumulated stoichiometric amounts of the corresponding CBAs. The recombinant strains VP44(pPC3) and VP44(pE43) grew on, and completely dechlorinated high concentrations (up to 10 mM), of 4-CBA and 4-CB and 2-CBA and 2-CB, respectively. Cell protein yield corresponded to complete oxidation of both biphenyl rings, thus confirming mineralization of the CBs. Hence, the use of CBA dehalogenase genes appears to be an effective strategy for construction of organisms that will grow on at least some congeners important for remediation of PCBs.

Hrywna, Y.; Tsoi, T.V.; Maltseva, O.V.; Quensen, J.F. III; Tiedje, J.M. [Michigan State Univ., East Lansing, MI (United States)

1999-05-01

316

affyPara--a Bioconductor Package for Parallelized Preprocessing Algorithms of Affymetrix Microarray Data  

PubMed Central

Microarray data repositories as well as large clinical applications of gene expression allow to analyse several hundreds of microarrays at one time. The preprocessing of large amounts of microarrays is still a challenge. The algorithms are limited by the available computer hardware. For example, building classification or prognostic rules from large microarray sets will be very time consuming. Here, preprocessing has to be a part of the cross-validation and resampling strategy which is necessary to estimate the rule’s prediction quality honestly. This paper proposes the new Bioconductor package affyPara for parallelized preprocessing of Affymetrix microarray data. Partition of data can be applied on arrays and parallelization of algorithms is a straightforward consequence. The partition of data and distribution to several nodes solves the main memory problems and accelerates preprocessing by up to the factor 20 for 200 or more arrays. affyPara is a free and open source package, under GPL license, available form the Bioconductor project at www.bioconductor.org. A user guide and examples are provided with the package.

Schmidberger, Markus; Vicedo, Esmeralda; Mansmann, Ulrich

2009-01-01

317

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

318

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

319

PFI-ZEKE (Pulsed Field Ionization-Zero Electron Kinetic Energy) para el estudio de iones  

NASA Astrophysics Data System (ADS)

Entre las áreas hacia donde ha evolucionado la Química en los últimos años están los estudios de sistemas con especies reactivas de alta energía y los dominados por fuerzas intermoleculares débiles, con energías de unas pocas kcal/mol. En efecto, el estudio de las propiedades de los iones, comenzando por su relación con la molécula neutra de la que procede, la energía de ionización, los estados vibracionales y rotacionales, energías de enlace de Van der Waals entre el ión y una amplia variedad de otras moléculas, sus confórmeros o isómeros y sus reacciones o semi-reacciones químicas están en la raíz de la necesidad de la espectroscopía conocida como PFI-ZEKE, Pulsed Field Ionization-Zero Electron Kinetic Energy. Entre las aplicaciones que requieren estos conocimientos se encuentran la generación de plasmas para la fabricación de semiconductores, memorias magnéticas, etc, así como los sistemas astrofísicos, la ionosfera terrestre, etc. La espectroscopía ZEKE es una evolución de las de fluorescencia inducida por láser, LIF, ionización multifotónica acrecentada por resonancia, REMPI, con uno y dos colores y acoplada a un sistema de tiempo de vuelo, REMPI-TOF-MS, y las espectroscopías de doble resonancia IR-UV y UV-UV. Sus espectros y la ayuda de cálculos ab inicio permite determinar las energías de enlace de complejos de van der Waals en estados fundamental y excitados, identificar confórmeros e isómeros, obtener energías de ionización experimentales aproximadas (100 cm-1) y otras variables de interés. Al igual que con LIF, REMPI y dobles resonancias, es posible utilizar muestras gaseosas, pero los espectros están muy saturados de bandas y su interpretación es difícil o imposible. Se evitan estas dificultades estudiando las moléculas o complejos en expansiones supersónicas, donde la T de los grados de libertad solo alcanzan unos pocos K. Para realizar experimentos de ZEKE hay que utilizar una propiedad recientemente descubierta, que va en contra de lo esperado en otros sistemas físicos y que consiste en que los altos estados Rydberg de átomos, moléculas y sus complejos de van der Waals (o de los iones) tienen tiempos de vida de centenas de ? s. En resumen, el experimento y la espectroscopía ZEKE consiste en excitar un átomo, molécula o cluster sucesivamente a dos estados excitados selectivos de manera que el final sea un estado Rydberg. A continuación se aplica un campo eléctrico variable que lo ioniza y después de un cierto retraso se aplica un campo eléctrico de extracción, tanto para el electrón como para el ión. El espectro de los iones, es un espectro ZEKE. Hay varias alternativas para hacer este último proceso. El estudio de la espectroscopía y propiedades de iones y sus clusters requiere el conocimiento detallado de la espectroscopía de la molécula neutra, los estados Rydberg, de los confórmeros y sus complejos. Todo ello implica el haber estudiado los sistemas por LIF, REMPI y doble resonancia (hole burning IR-UV, UV-UV). Además solo es posible interpretar los resultados y obtener la información contenida en los espectros con ayuda de cálculos cuánticos ab initio. Hasta el momento hemos aplicado tanto el ZEKE como el conjunto de técnicas mencionadas anteriormente, a varias molécula de interés químico general como anilina y sus derivados, así como sus complejos con agua y amoniaco. Sin embargo, el método es muy versátil y puede aplicarse a iones de átomos, iones múltiples, moléculas sencillas y sus clusters así como a sus semi-reacciones. Como ejemplo de uno de estos espectros PFI-ZEKE se presenta aquí el caso del amonibenzonitrilo, ABN y solamente en su estado fundamental. En la conferencia se presentarán espectros ZEKE del ABN y moléculas similares en estados vibracionales intermedios (islas de estabilidad), así como la determinación de potenciales de ionización precisos, energías de enlace de compuestos del ión con varios disolventes y otras propiedades de interés, discutiendo sus resultados.

Castaño, F.; Fernández, J. A.; Basterretxea, A. Longarte. F.; Sánchez Rayo, M. N.; Martínez, R.

320

Dissection of the ATPase active site of P1 ParA reveals multiple active forms essential for plasmid partition.  

PubMed

The segregation, or partition, of bacterial plasmids is driven by the action of plasmid-encoded partition ATPases, which work to position plasmids inside the cell. The most common type of partition ATPase, generally called ParA, is represented by the P1 plasmid ParA protein. ParA interacts with P1 ParB (the site-specific DNA binding protein that recognizes the parS partition site), and interacts with the bacterial chromosome via an ATP-dependent nonspecific DNA binding activity. ParA also regulates expression of the par genes by acting as a transcriptional repressor. ParA requires ATP for multiple steps and in different ways during the partition process. Here, we analyze the properties of mutations in P1 ParA that are altered in a key lysine in the Walker A motif of the ATP binding site. Four different residues at this position (Lys, Glu, Gln, Arg) result in four different phenotypes in vivo. We focus particularly on the arginine substitution (K122R) because it results in a worse-than-null and dominant-negative phenotype called ParPD. We show that ParAK122R binds and hydrolyzes ATP, although the latter activity is reduced compared with wild-type. ParAK122R interacts with ParB, but the consequences of the interaction are damaged. The ability of ParB to stimulate the ATPase activity of ParA in vitro and its repressor activity in vivo is defective. The K122R mutation specifically damages the disassembly of ParA-ParB-DNA partition complexes, which we believe explains the ParPD phenotype in vivo. PMID:23632076

Vecchiarelli, Anthony G; Havey, James C; Ing, Lori L; Wong, Erin O Y; Waples, William G; Funnell, Barbara E

2013-04-30

321

ParaHox gene expression in larval and postlarval development of the polychaete Nereis virens (Annelida, Lophotrochozoa)  

PubMed Central

Background Transcription factors that encode ANTP-class homeobox genes play crucial roles in determining the body plan organization and specification of different organs and tissues in bilaterian animals. The three-gene ParaHox family descends from an ancestral gene cluster that existed before the evolution of the Bilateria. All three ParaHox genes are reported from deuterostomes and lophotrochozoans, but not to date from any ecdysozoan taxa, and there is evidence that the ParaHox genes, like the related Hox genes, were ancestrally a single chromosomal cluster. However, unlike the Hox genes, there is as yet no strong evidence that the ParaHox genes are expressed in spatial and temporal order during embryogenesis. Results We isolated fragments of the three Nereis virens ParaHox genes, then used these as probes for whole-mount in situ hybridization in larval and postlarval worms. In Nereis virens the ParaHox genes participate in antero-posterior patterning of ectodermal and endodermal regions of the digestive tract and are expressed in some cells in the segment ganglia. The expression of these genes occurs in larval development in accordance with the position of these cells along the main body axis and in postlarval development in accordance with the position of cells in ganglia along the antero-posterior axis of each segment. In none of these tissues does expression of the three ParaHox genes follow the rule of temporal collinearity. Conclusion In Nereis virens the ParaHox genes are expressed during antero-posterior patterning of the digestive system (ectodermal foregut and hindgut, and endodermal midgut) of Nereis virens. These genes are also expressed during axial specification of ventral neuroectodermal cell domains, where the expression domains of each gene are re-iterated in each neuromere except for the first parapodial segment. These expression domains are probably predetermined and may be directed on the antero-posterior axis by the Hox genes, whose expression starts much earlier during embryogenesis. Our results support the hypothesis that the ParaHox genes are involved in antero-posterior patterning of the developing embryo, but they do not support the notion that these genes function only in the patterning of endodermal tissues.

Kulakova, Milana A; Cook, Charles E; Andreeva, Tatiana F

2008-01-01

322

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

323

Determination of the Ortho to Para Ratio of H2Cl+ and H2O+ from Submillimeter Observations  

NASA Astrophysics Data System (ADS)

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.

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

324

Para-NO-aspirin inhibits NF-?B and induces apoptosis in B-cell progenitor acute lymphoblastic leukemia.  

PubMed

Although patients with acute lymphoblastic leukemia (ALL) usually achieve complete remission, disease relapse is common and difficult to treat. Para-NO-aspirin (para-NO-ASA) is a novel drug with demonstrated efficacy against a number of solid tumors and most recently chronic lymphocytic leukemia. In this study, we used ALL cell lines to assess the effects on cell viability by flow cytometry and investigated the mechanism of cell death using chemical inhibitors of key molecules and assessed the effects by flow cytometry, electrophoretic mobility shift assay, Western blotting, and quantitative reverse transcription polymerase chain reaction. Para-NO-ASA induced cell death in the pre-B ALL cell lines in association with increased reactive oxygen species, and suppression of nuclear factor-?B (NF-?B) activity. Chemical inhibitors of NF-?B similarly induced apoptosis in ALL cells, suggesting a role for suppression of NF-?B in para-NO-ASA-induced cell death. Modulation of NF-?B was not via regulation of I?B but potentially through suppression of ROCK1 and loss of reduced glutathione. Our results demonstrate that para-NO-ASA potently induces apoptosis in B-lineage ALL cells via a reactive oxygen species-dependent mechanism that is associated with suppression of NF-?B activity. PMID:22100881

Khan, Naveed I; Cisterne, Adam; Baraz, Rana; Bradstock, Kenneth F; Bendall, Linda J

2011-11-17

325

Creation and evolution of net proton hyperpolarization arising from para-hydrogenation  

NASA Astrophysics Data System (ADS)

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 2IzAIzB) is created but also difference of enhanced polarizations (IzA-IzB). 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.

Reineri, Francesca; Bouguet-Bonnet, Sabine; Canet, Daniel

2011-05-01

326

A method to obtain a well-defined fraction of respirable para-aramid fibers.  

PubMed

We developed a preparation method to obtain respirable-sized fractions of para-aramid fibers. The procedure, based on floatability, consists of stirring and subsequent settling of p-aramid pulp in distilled water. Two distinct phases are obtained, with small fibers in the upper part of the suspension, which represents about 33% of the total volume. Optimal results were obtained when 2.0 g pulp was stirred for 15 hr in 800 ml distilled water containing 0.125% ethanol and settled for 5 hr. The mass yield ranged between 0.4 and 0.6%, more than 90% of the particles had an aspect ratio > or = 3:1. The mean fiber length was about 6 microns, and the mean fiber diameter was about 0.4 microns as determined by transmission and scanning electron microscopy. The number of fibers obtained was 4 x 10(6) fibers/micrograms under our standard conditions. PMID:8119251

Schins, R P; Gaudichet, A; Jaurand, M C

1993-10-01

327

ACT-asthma control y tratamiento para niños: a progress report.  

PubMed

A randomized clinical trial is in progress to evaluate an asthma educational program for Latino children and their parents. The intervention, "ACT-Asma Control y Tratamiento Para Niños," was adapted from ACT for Kids, an asthma self-management program for English-speaking families. Results of a pilot study indicated that socioeconomic status was a critical variable to be considered in the design of such programs. Latino children and parents encounter significant barriers to access and continuity of medical care. Therefore, the intervention was redesigned to include "linkages" using a nurse to reduce barriers and to coordinate care. The lesson plans emphasize concrete, experimental learning experiences, with repetition of key points in each session. PMID:3654235

Lewis, M A; de la Sota, A; Rachelefsky, G; Lewis, C E; Quinones, H; Richards, W

1987-01-01

328

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

329

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

330

Para-aminosalicylic acid acts as an alternative substrate of folate metabolism in Mycobacterium tuberculosis.  

PubMed

Folate biosynthesis is an established anti-infective target, and the antifolate para-aminosalicylic acid (PAS) was one of the first anti-infectives introduced into clinical practice on the basis of target-based drug discovery. Fifty years later, PAS continues to be used to treat tuberculosis. PAS is assumed to inhibit dihydropteroate synthase (DHPS) in Mycobacterium tuberculosis by mimicking the substrate p-aminobenzoate (PABA). However, we found that sulfonamide inhibitors of DHPS inhibited growth of M. tuberculosis only weakly because of their intracellular metabolism. In contrast, PAS served as a replacement substrate for DHPS. Products of PAS metabolism at this and subsequent steps in folate metabolism inhibited those enzymes, competing with their substrates. PAS is thus a prodrug that blocks growth of M. tuberculosis when its active forms are generated by enzymes in the pathway they poison. PMID:23118010

Chakraborty, Sumit; Gruber, Todd; Barry, Clifton E; Boshoff, Helena I; Rhee, Kyu Y

2012-11-01

331

Searching for Auxetics with DYNA3D and ParaDyn  

SciTech Connect

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, W G; Hoover, C G

2004-09-11

332

Understanding the relationship between gas and ice : experimental investigations on ortho-para ratios  

NASA Astrophysics Data System (ADS)

Numerous hydrogenated molecules observed in comets and the interstellar medium present nuclear spin isomers. The non-thermal ortho: para ratios measured in space are believed to be of high diagnostic value, allowing remote measurement of physical conditions prevailing in the past, such as the initial temperature associated with a molecular formation or condensation. The lack of laboratory studies on interactions at the gas-solid interface limits our current interpretation of observations. Recent progress in nuclear spin conversion (NSC) dynamics are discussed in this paper. Results on water and methane in cryogenic matrices illustrate the conversion mechanisms within the condensed phase at very low temperatures. NSC of molecular hydrogen at the surface of 10 K Amorphous Solid Water (ASW) shows surface mediated conversion processes for molecular hydrogen. NSC involving molecular ices are discussed in the light of few recent studies, including UV photodesorption investigations.

Fillion, J.-H.; Bertin, M.; Lekic, A.; Moudens, A.; Philippe, L.; Michaut, X.

2012-02-01

333

Excited-state switching by per-fluorination of para-oligophenylenes.  

PubMed

Fluorination has become a versatile route to tune the electronic and optical properties of organic conjugated materials. Herein we report a new phenomenon, excited-state switching by per-fluorination of para-oligophenylenes, placing a low intensity 1(1)B(2) state below the 1(1)B(1) state, giving rise to large Stokes shifts. The switching is attributed to the specific impact of fluorine on the delocalized and localized frontier orbitals as elucidated by quantum-chemical calculations. The sterical demands of the fluorine atom additionally diminish efficient conjugation along the chain, leading to hypsochromic shifts with respect to the unsubstituted counterparts and to a weak chain length dependence of the absorption and unstructured emission spectra and enhanced internal conversion. PMID:21974537

Milián-Medina, Begoña; Varghese, Shinto; Ragni, Roberta; Boerner, Herbert; Ortí, Enrique; Farinola, Gianluca M; Gierschner, Johannes

2011-09-28

334

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

335

Constraining the ortho-to-para ratio of H2 with anomalous H_2CO absorption  

NASA Astrophysics Data System (ADS)

Context: The ortho-to-para ratio (OPR) of molecular hydrogen is a fundamental parameter in understanding the physics and chemistry of molecular clouds. In dark and cold regions, however, H2 is not directly observable and the OPR of H2 in these sources has so far remained elusive. Aims: We show that the 6 cm absorption line of ortho-formaldehyde (H2CO) can be employed to constrain both the density and the OPR of H2 in dark clouds. Methods: Green Bank Telescope (GBT) observations of ortho-H2CO toward the molecular cloud Barnard 68 (B68) are reported. Non-LTE radiative transfer calculations combined with the well-constrained structure of B68 are then employed to derive the physical conditions in the absorption region. Results: We provide the first firm confirmation of the Townes & Cheung mechanism: propensity rules for the collisions of H2CO with H2 molecules are responsible for the sub-2.7 K cooling of the 6 cm doublet. Non-LTE calculations show that in the absorption region of B68, the kinetic temperature is ˜ 10 K, the ortho-H2CO column density amounts to ˜ 2.2× 1013 cm-2, the H2 density is in the range 1.4{-}2.4× 10 4 cm-3, and the OPR of H2 is close to zero. Our observations thus provide fresh evidence that H2 is mostly in its para form in the cold gas, as expected from theoretical considerations. Our results also suggest that formaldehyde absorption originates in the edge of B68, at visual extinctions A_V? 0.5 mag. This work has been inspired by our colleague and friend Pierre Valiron, who passed away in August 2008. This paper is dedicated to his memory.

Troscompt, N.; Faure, A.; Maret, S.; Ceccarelli, C.; Hily-Blant, P.; Wiesenfeld, L.

2009-11-01

336

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

2013-01-02

337

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

338

Silver(I) and mercury(II) complexes of meta- and para -xylyl linked bis(imidazol-2-ylidenes)  

Microsoft Academic Search

Mononuclear silver and mercury complexes bearing bis-N-heterocyclic carbene (NHC) ligands with linear coordination modes have been prepared and structurally characterised. The\\u000a complexes form metallocyclic structures that display rigid solution behaviour. A larger metallocycle of the form [L2Ag2]2+ [where L = para-bis(N-methylimidazolylidene)xylylene] has been isolated from the reaction of para-xylylene-bis(N-methylimidazolium) chloride and Ag2O. Reaction of silver- and mercury-NHC complexes with Pd(NCCH3)2Cl2 affords palladium-NHC

Murray V. Baker; David H. Brown; Rosenani A. Haque; Brian W. Skelton; Allan H. White

2009-01-01

339

Evaluation of para-dichlorobenzene emissions from solid moth repellant as a source of indoor air pollution  

SciTech Connect

The paper reports results of dynamic and static chamber tests to evaluate para-dichlorobenzene emission rates from mothcakes. The data were analyzed by a model that assumes that the emission rate is controlled by gas-phase mass transfer. Results indicate that the para-dichlorobenzene emission from mothcakes is a temperature-sensitive sublimation process. Full-scale house tests were also conducted to measure mass transfer coefficients based on the model developed. The values of the mass transfer coefficient obtained are very comparable to those estimated by theoretical heat transfer studies.

Chang, J.C.S.; Krebs, K.A.

1992-01-01

340

Rotational excitation of 45 levels of ortho/para-H2O by excited ortho/para-H2 from 5 K to 1500 K: state-to-state, effective, and thermalized rate coefficients  

NASA Astrophysics Data System (ADS)

Aims: This work deals with the rotational excitation of ortho/para-H2O with para/ortho-H2 so that thermalized de-(excitation) rate coefficients up to 1500 K for the first 45th level of ortho/para-H2O are provided. Results are available in BASECOL with state-to-state rate coefficients, their fitting coefficients, and effective rate coefficients. In addition, we provide a routine that combines all data in order to create thermalized rate coefficients. Methods: Calculations were performed with the close coupling (CC) method over the whole energy range, using the same 5D potential energy surface (PES) as the one employed in previous papers. The current CC results were compared with thermalized quasi-classical trajectory (QCT) calculations using the same PES and with previous quantum calculations obtained between T = 20 K and T = 140 K with a different PES. The relative strengths of water excitation rate coefficients when water is excited with ortho-H2 versus para-H2 was also analyzed. Results: For collision with para-H2, the rotation-rotation process is found to be the dominant process for inelastic transfer for some water transitions, implying that calculations must include the j2 = 2 level. An important result of this paper is that j2 = 1 and j2 = 2 effective rate coefficients are very similar so that either j2 = 1 or j2 = 2 need to be calculated for astrophysical applications. In addition, at high temperature ratios of j2 = 2 (1) over j2 = 0, effective rate coefficients converge towards one to within a few percent. This study confirms that j2 = 3 effective rate coefficients are within 20% to j2 = 1 effective rate coefficients. Conclusions: For astrophysical applications, these results imply that future collisional excitation of light molecules with H2 should be carried out with para-H2, including j2 = 2, so as to obtain correct effective j2 = 0 effective rate coefficients and using the j2 = 2 effective rate coefficients for all excited j2 effective rate coefficients. In contrast, collisional excitation of heavy molecules with H2 might be restricted to para-H2 with j2 = 0 and to ortho-H2 with j2 = 1, using the j2 = 1 rate coefficients for all excited j2 effective rate coefficients. These conclusions should simplify the future methodological choice for collisional excitation calculations applied to interstellar/circumstellar media.

Daniel, F.; Dubernet, M.-L.; Grosjean, A.

2011-12-01

341

Gestión por competencias: importante para las pymes maquila de pantalón en índigo en la ciudad de Bogotá  

Microsoft Academic Search

Este artículo presenta una revisión de literatura internacional y nacional, sobre temas como el de competencias, los tipos de competencias, competencias laborales y proceso de implementación de la gestión por competencias. Adicionalmente, se muestra la reseña sobre la gestión por competencias en Colombia, así como la metodología utilizada para el trabajo de campo con relación al tema del artículo y

Nathalia Andrea Martínez Valero; Juan Carlos Rincón Gaviria

2010-01-01

342

Ultrastructural study shows morphologic features of apoptosis and para-apoptosis in megakaryocytes from patients with idiopathic thrombocytopenic purpura  

Microsoft Academic Search

To investigate whether altered megakaryo- cyte morphology contributes to reduced platelet production in idiopathic thrombo- cytopenic purpura (ITP), ultrastructural analysis of megakaryocytes was per- formed in 11 ITP patients. Ultrastructural abnormalities compatible with (para-)apo- ptosis were present in 78% 14% of ITP megakaryocytes, which could be reversed by in vivo treatment with prednisone and intravenous immunoglobulin. Immunohis- tochemistry of bone

Ewout J. Houwerzijl; Nel R. Blom; Johannes J. L. van der Want; Mariet T. Esselink; Jan J. Koornstra; Jan W. Smit; Henk Louwes; Edo Vellenga; Joost Th; M. de Wolf

343

LA UTILIZACIÓN DE MAPAS CONCEPTUALES COMO ESTRATEGIA DIDÁCTICA PARA LA CONSTRUCCIÓN Y ORGANIZACIÓN DEL PENSAMIENTO EN EDAD PREESCOLAR  

Microsoft Academic Search

A continuación se exponen los resultados y conclusiones de una investigación, basada en la implementación de una propuesta metodológica innovadora para la construcción de Mapas Conceptuales en edad preescolar. Esta experiencia tuvo lugar en dos jardines Infantiles estatales de la ciudad de Cartago, Costa Rica. La población infantil la conformó un grupo de niños y niñas con edades entre los

Jenny Brenes; Ana Sofía Coto; Gloria Hurtado

344

Millimeter-Wave Spectroscopy of S2Cl2: A Candidate Molecule for Measuring Ortho-Para Transition  

NASA Astrophysics Data System (ADS)

S2Cl2 is a candidate for the observation of ortho-para transition. To estimate the ortho-para mixing in a hyperfine-resolved rotational state, pure rotational transitions were measured by millimeter-wave (mm-wave) spectroscopy using two different experimental set-ups. The transitions from the term value around 20 K was measured with a supersonic jet and those around 200 K were measured with a dry ice cooled gas cell. Several hundred peaks were assigned for the naturally abundant S235Cl2 and S235Cl37Cl isotopic species and the rotational molecular parameters including the fourth-order and sixth-order centrifugal distortion constants were determined. The hyperfine structures were partly resolved in some Q-branch transitions, which were well described with the hyperfine constants determined by FTMW spectroscopy in the centimeter-wave region. With the new rotational constants determined in our study and the previous hyperfine constants, it will be possible to obtain a more reliable ortho-para mixing ratio and to narrow down the possible candidate transitions in the mm-wave region for the observation of ortho-para transition.

Dehghani, Zeinab Tafti; Ota, Shinji; Mizoguchi, Asao; Kanamori, Hideto

2013-10-01

345

Organización del trabajo y diseño del sistema de pago para la actividad de preparacion de materia prima  

Microsoft Academic Search

El presente trabajo fue realizado con el objetivo de resolver o disminuir el efecto negativo de dos problemas fundamentales que existían en la Fábrica de Tabacos Torcidos a mano para la Exportación Camajuaní, los cuales consistían en : 1ro La mala calidad de la materia prima y 2do El salario recibido por el grupo de trabajadores encargados de la preparación

Alexis Águila Espinosa; Silvia López Hernández

2010-01-01

346

Hysteretic sorption of light gases by a porous metal-organic framework containing tris(para-carboxylated) triphenylphosphine oxide.  

PubMed

The porous metal-organic framework (MOF) PCM-4, based on tris(para-carboxylated) triphenylphosphine oxide, contains atypical, polar organic substituents; the material exhibits a hysteretic sorption of Ar, N2 and O2, and demonstrates the advantage of ligands of this type. PMID:18566715

Humphrey, Simon M; Oungoulian, Shaunt E; Yoon, Ji Woong; Hwang, Young Kyu; Wise, Erica R; Chang, Jong-San

2008-04-21

347

The Role Of Women In Popular Education In Bolivia: A Case Study Of The "Oficina Juridica Para La Mujer"  

ERIC Educational Resources Information Center

|This study examines how the Education Office of the "Oficina Juridica Para la Mujer" [Women's Legal Office] , a community-based popular education organization in Cochabamba, Bolivia, works with women to address personal, legal, and policy issues through local leadership training and popular education methodology. We investigate the…

Kollins, Judith M.; Hansman, Catherine A.

2005-01-01

348

Malaria Rapid Diagnostic Devices: Performance Characteristics of the ParaSight F Device Determined in a Multisite Field Study  

Microsoft Academic Search

Microscopic detection of parasites has been the reference standard for malaria diagnosis for decades. However, difficulty in maintaining required technical skills and infrastructure has spurred the development of several nonmicroscopic malaria rapid diagnostic devices based on the detection of malaria parasite antigen in whole blood. The ParaSight F test is one such device. It detects the presence of Plasmodium falciparum-specific

J. RUSS FORNEY; ALAN J. MAGILL; CHANSUDA WONGSRICHANALAI; JEERAPHAT SIRICHAISINTHOP; CHRISTIAN T. BAUTISTA; D. GRAY HEPPNER; R. SCOTT MILLER; CHRISTIAN F. OCKENHOUSE; ALEX GUBANOV; ROBYN SHAFER; CAROLINE CADY DEWITT; HIGINIO A. QUINO-ASCURRA; KENT E. KESTER; KEVIN C. KAIN; DOUGLAS S. WALSH; W. RIPLEY BALLOU

2001-01-01

349

ParaCalc ®—A novel tool to evaluate the economic importance of worm infections on the dairy farm  

Microsoft Academic Search

Subclinical infections with gastrointestinal nematodes and liver fluke are important causes of production losses in grazing cattle. Although there is an extensive compilation of literature describing the effect of these infections on animal performance, only a few attempts have been made to convert these production losses to an economic cost. Here, we propose a novel tool (ParaCalc®), available as a

Johannes Charlier; Mariska Van der Voort; Henk Hogeveen; Jozef Vercruysse

2012-01-01

350

Millimeter-Wave Spectroscopy of S2Cl2: A Candidate Molecule for Measuring Ortho-Para Transition.  

PubMed

S2Cl2 is a candidate for the observation of ortho-para transition. To estimate the ortho-para mixing in a hyperfine-resolved rotational state, pure rotational transitions were measured by millimeter-wave (mm-wave) spectroscopy using two different experimental set-ups. The transitions from the term value around 20 K was measured with a supersonic jet and those around 200 K were measured with a dry ice cooled gas cell. Several hundred peaks were assigned for the naturally abundant S2(35)Cl2 and S2(35)Cl(37)Cl isotopic species and the rotational molecular parameters including the fourth-order and sixth-order centrifugal distortion constants were determined. The hyperfine structures were partly resolved in some Q-branch transitions, which were well described with the hyperfine constants determined by FTMW spectroscopy in the centimeter-wave region. With the new rotational constants determined in our study and the previous hyperfine constants, it will be possible to obtain a more reliable ortho-para mixing ratio and to narrow down the possible candidate transitions in the mm-wave region for the observation of ortho-para transition. PMID:23634992

Dehghani, Zeinab Tafti; Ota, Shinji; Mizoguchi, Asao; Kanamori, Hideto

2013-05-29

351

Communications: Development and characterization of a source of rotationally cold, enriched para-H{sub 3}{sup +}  

SciTech Connect

In an effort to develop a source of H{sub 3}{sup +} that is almost entirely in a single quantum state (J=K=1), we have successfully generated a plasma that is enriched to {approx}83% in para-H{sub 3}{sup +} at a rotational temperature of 80 K. This enrichment is a result of the nuclear spin selection rules at work in hydrogenic plasmas, which dictate that only para-H{sub 3}{sup +} will form from para-H{sub 2}, and that para-H{sub 3}{sup +} can be converted to ortho-H{sub 3}{sup +} by subsequent reaction with H{sub 2}. This is the first experimental study in which the H{sub 2} and H{sub 3}{sup +} nuclear spin selection rules have been observed at cold temperatures. The ions were produced from a pulsed solenoid valve source, cooled by supersonic expansion, and interrogated via continuous-wave cavity ringdown spectroscopy.

Tom, Brian A.; Mills, Andrew A.; Wiczer, Michael B.; Crabtree, Kyle N. [Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); McCall, Benjamin J. [Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

2010-02-28

352

Solvent and concentration effects on the visible spectra of tri- para-dialkylamino-substituted triarylmethane dyes in liquid solutions  

Microsoft Academic Search

We have characterized the spectroscopy properties of crystal violet (CV+) and ethyl violet (EV+) in liquid solutions as a function of the solvent type and dye concentration. The analysis of how solvent properties and dye concentration affects the electronic spectra of these tri-para-dialkylamino substituted tryarylmethane (TAM+) dyes was performed on the basis of two spectroscopic parameters, namely the difference in

Carla S. Oliveira; Kerlley P. Branco; Mauricio S. Baptista; Guilherme L. Indig

2002-01-01

353

DERECHO E INNOVACIÓN METODOLÓGICA PARA LA ADQUISICIÓN DE LAS COMPETENCIAS Y HABILIDADES EN EL TITULO DE GRADO EN TRABAJO SOCIAL  

Microsoft Academic Search

El artículo presenta, en primer lugar, la estrecha relación entre el Derecho y el Trabajo Social y, en segundo lugar, la metodología innovadora en la docencia de las prácticas curriculares del Titulo de Grado de Trabajo Social de la Universidad de Murcia que aglutina la cooperación docente, profesional e institucional. El objetivo del Titulo es formar profesionales preparados para desarrollar

Enrique Pastor Seller

2011-01-01

354

Las lenguas como elementos de cohesión social. Del multilingüismo al desarrollo de habilidades para la comunicación intercultural  

Microsoft Academic Search

Resumen La lengua, entendida como factor de cohesión social, ha sido considerada desde diversas perspectivas asimilacionistas como necesaria y prioritaria para la integración en una sociedad receptora de quienes proceden de otras comunidades lingüísticas y culturales. Este artículo propone una reflexión sobre la diversidad como elemento ineludible en la construcción de una nueva ciudadanía multicultural en la que la lengua

Martina Tuts; Colectivo Yedra

355

Expectativas, volatilidad del mercado de capitales y comportamiento de la inversión privada. Teoría y evidencia empírica para Brasil  

Microsoft Academic Search

La investigación que se resume en este trabajo representa la primera etapa de un esfuerzo que pretende analizar algunos aspectos importantes de la interacción entre el mercado accionario y el comportamiento de la inversión de las empresas, para un número de países en desarrollo endeudados. El presente trabajo analiza el caso de Brasil y presenta algunos resultados de estimaciones preliminares

Mansoor Dailami

356

Estudio para la prevención del cáncer necesita voluntarias: El Estudio del Tamoxifeno y Raloxifeno (STAR) se realiza en Norteamérica  

Cancer.gov

El Estudio del Tamoxifeno y Raloxifeno (STAR, por sus siglas en inglés), uno de los estudios más importantes realizados para la prevención del cáncer del seno, está ahora reclutando voluntarias en más de 400 centros en los Estados Unidos, Puerto Rico y Canadá.

357

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

358

Quantification of para-phenylenediamine and heavy metals in henna dye.  

PubMed

Henna (Lawsonia inermis, family Lythraceae) is a shrub cultivated in India, Sri Lanka and North Africa and contains the active dye lawsone (2-hydroxy-1,4-naphthoquinone). Henna dye is obtained from the dried leaves, which are powdered and mixed with oil or water and are used to prepare hair and body dyes. Temporary henna tattoos are readily available worldwide, last on the skin for several weeks and offer a self-limited, convenient alternative to a permanent tattoo. The addition of para-phenylenediamine (PPD), which is widely recognised as a sensitizer, increases the risk of allergic contact dermatitis from henna tattoo mixtures, and a number of cases have been reported. We examined 15 henna samples available in Korea for the presence of PPD and heavy metals such as nickel, cobalt, chromium, lead and mercury using high-performance liquid chromatography (HPLC), atomic absorption spectroscopy (AAS), mercury analyser and inductively coupled plasma emission spectroscopy. PPD, nickel and cobalt were detected in 3, 11 and 4 samples, respectively. PMID:16842550

Kang, Ik-Joon; Lee, Mu-Hyoung

2006-07-01

359

Determination of para-Phenylenediamine (PPD) in Henna in the United Arab Emirates  

PubMed Central

Henna is very popular in the United Arab Emirates (UAE); it is part of the culture and traditions. Allergy to natural henna is not usual; however the addition of para-phenylenediamine (PPD) to the natural henna increases the risk of allergic contact dermatitis. The objectives of the study were to identify the presence and concentration of PPD in henna available in UAE. Fifteen henna salons were selected randomly from three cities in UAE. Twenty five henna samples were acquired from these selected salons. The presence of PPD in henna samples was determined qualitatively and quantitatively using High Performance Liquid Chromatography (HPLC). The study showed that PPD was present in all of the black henna samples at concentrations ranging between 0.4% and 29.5% and higher than that recommended for hair dyes in most of the black henna samples. The presence of PPD in the black henna increases the risk of allergic contact dermatitis among users of black henna and a number of cases have already been reported in UAE.

Al-Suwaidi, Ayesha; Ahmed, Hafiz

2010-01-01

360

Hematopathology in Sprague-Dawley rats following sub-chronic topical application of para-phenylenediamine.  

PubMed

The aim of the present study was to analyze the hematological profile of male SD rats treated topically with aqueous solution of para-phenylenediamine (PPD), a component of almost all hair dye formulations. The rats were painted with different concentration of PPD (0, 1, 2 and 3 mg Kg(-1) Day(-1)) for 90 days and then sacrificed. The hematological profile indicated severe anemia characterized by significant (p < 0.05, 0.001) reduction of total RBC count (59%), packed cell volume (PCV, 50%) and haemoglobin level (70%) in the peripheral blood of PPD treated animals when compared to control group. The leucocytes profile exhibited an overall elevation of around twofold as compared to the control group with significant lymphocytosis (44.4%) and a higher percentage of blast cells (8.5%) as well as smudge (10.3%) and hairy cells (6.2%) in the peripheral blood of treated animals. Histopathological examination of spleen from treated rat's exhibit red pulp congestion, expansion of the germinal centre, hyperplasia of the membrane capsule and extensive accumulation of hemosidderin pigments in the red pulp of the spleen. Overall this study indicated an abnormal pathophysiological condition indicating adverse effect of PPD in the treated animal groups. The risk assessment of hair dye formulation needs to be reviewed in view of widespread usage of paraphenylenediamine in almost all hair dye formulation. PMID:22886424

Bharali, Manuj Kr; Dutta, Karabi

2012-08-11

361

Foco Nasmyth para el telescopio 2,15mts. de CASLEO  

NASA Astrophysics Data System (ADS)

En principio, este proyecto intenta lograr el mayor aprovechamiento posible del instrumental que se dispone, buscando la manera de optimizar y hacer más eficiente el servicio que brinda el CASLEO a la comunidad astronómica. El mismo consiste en utilizar dispositivos ya existentes en el telescopio, y darle una utilidad. Tal es el caso del camino óptico destinado al foco Coude. Si tenemos en cuenta que disponemos de un tercer espejo Coude, con todos sus mecanismos automatizados, (actualmente sin uso), una distancia apropiada del plano focal, el espacio y el lugar físico necesario para instalar un periférico, es posible la habilitación de un foco Nasmyth en el telescopio 2,15mts. El hecho de contar con este nuevo foco, redundará en importantes beneficios. En primer lugar, posibilitará la observación, casi simultánea, con dos instrumentos. Otro aspecto a tener en cuenta, es que disminuirá el frecuente cambio del instrumental periférico, motivo este que degrada su ideal puesta a punto. Por último, también de interés, es de destacar su escaso costo de ejecución.

Casagrande, A. R.

362

From clusters to fibers: Parameters for discontinuous para-hexaphenylene thin film growth  

SciTech Connect

All relevant steps of discontinuous thin film growth of para-hexaphenylene on muscovite mica (0 0 1) from wetting layer over small and large clusters to nanofibers are observed and investigated in detail by a combined polarized fluorescence and atomic force microscopy study. From a variation of film thickness and surface temperature, we determine effective activation energies for cluster growth of 0.17 eV, for nanofiber length growth of 0.46 eV, for width growth of 0.19 eV, and for height growth of 0.07 eV. The corresponding exponential prefactors for the nanofiber growth are 1x10{sup 9}, 6x10{sup 4}, and 3x10{sup 2} nm. Polarized fluorescence studies reveal that nanofibers grow along the grooves of the mica surface and that they do not change direction if they cross an even number of mica surface steps, while they change direction by 120 deg. for an odd number of steps. These results are taken as an input for a model of the unidirectional growth process on mica. Absolute parameters allowing one to grow nanofibers of predetermined morphology via organic molecular beam epitaxy are also given.

Kankate, Laxman; Balzer, Frank; Niehus, Horst [Humboldt-Universitaet zu Berlin, Newtonstr. 15, D-12489 Berlin (Germany); Rubahn, Horst-Guenter [Mads Clausen Institute, NanoSYD, Syddansk Universitet, DK-6400 Soenderborg (Denmark)

2008-02-28

363

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

2012-12-20

364

Level anti-crossings in ParaHydrogen Induced Polarization experiments with Cs-symmetric molecules  

NASA Astrophysics Data System (ADS)

Hyperpolarization by means of ParaHydrogen Induced Polarization (PHIP) has found increasing applications since its discovery. However, in the last decade only a few experiments have been reported describing the hydrogenation of symmetric molecules. A general AA?BB? system is studied here. Calculations of the spin dynamics with the density matrix formalism support the experimental findings, providing profound understanding of the experiments in Cs-symmetric molecules. Level anti-crossings between states related to the triplet and the singlet state of one pair of the protons are identified as being responsible for hyperpolarization transfer in a PHIP experiment, when the former p-H2 protons occupy the sites AA?.The hydrogenation of acetylene dicarboxylic acid dimethylester with parahydrogen is used to illustrate the case. The theoretical treatment applied to this particular reaction explains the signal enhancements in both groups of protons in the spectrum when the sample is placed in the proper magnetic field strength, including the phase inversion of the signal of the methyl group.The treatment described here can be extended to every molecule which can be approximated as an AA?BB? system.

Buljubasich, L.; Franzoni, M. B.; Spiess, H. W.; Münnemann, K.

2012-06-01

365

Coarse-grain model of the benzene ring with para-substituents in the molecule  

NASA Astrophysics Data System (ADS)

A new two-site coarse-grain model of the benzene ring with substituents in the para-position is proposed for use with multiscale simulations. The model uses a modified Lennard-Jones potential and introduces an additional shifting parameter to the description of the atom-atom interactions. Furthermore, the model separates sets of parameters of Van-der-Waals interactions into inter- and intramolecular. The shifting parameter is specified separately for each pair of atom types for both inter- and intramolecular interactions. The model itself consists of two superatoms. It allows for high speed calculations, ``remembers'' the benzene ring orientation in multiscale simulations, and can be used together with well-known sets of ``united atoms'' potentials. This model was tested on p-xylene, 1-ethyl-4-methylbenzene, and 1-methyl-4-propylbenzene. Structural properties for all three substances in the full-atomic model, the ``united atoms'' model, and the suggested coarse-grained model are discussed. The results demonstrate that the local structure derived from the coarse-grained model is very similar to that derived from the ``united atoms'' model.

Neverov, Vladimir S.; Komolkin, Andrei V.

2012-03-01

366

A method to obtain a well-defined fraction of respirable para-aramid fibers.  

PubMed Central

We developed a preparation method to obtain respirable-sized fractions of para-aramid fibers. The procedure, based on floatability, consists of stirring and subsequent settling of p-aramid pulp in distilled water. Two distinct phases are obtained, with small fibers in the upper part of the suspension, which represents about 33% of the total volume. Optimal results were obtained when 2.0 g pulp was stirred for 15 hr in 800 ml distilled water containing 0.125% ethanol and settled for 5 hr. The mass yield ranged between 0.4 and 0.6%, more than 90% of the particles had an aspect ratio > or = 3:1. The mean fiber length was about 6 microns, and the mean fiber diameter was about 0.4 microns as determined by transmission and scanning electron microscopy. The number of fibers obtained was 4 x 10(6) fibers/micrograms under our standard conditions. Images p414-a Figure 1. Figure 2. Figure 3.

Schins, R P; Gaudichet, A; Jaurand, M C

1993-01-01

367

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

368

Tailoring the film morphology of para-hexaphenyl on KCl(001) by surface temperature  

NASA Astrophysics Data System (ADS)

Ultra-thin films of para-hexaphenyl (6P) were prepared on potassium chloride(001) utilising physical vapour deposition under well-defined ultra-high-vacuum conditions. The 6P growth characteristics were studied as a function of substrate temperature. For this purpose, in situ X-ray photoelectron spectroscopy (XPS) in combination with thermal desorption spectroscopy (TDS) was applied to reveal the kinetics of the layer growth. Ex situ atomic force microscopy (AFM) was used to determine the film morphology. At the initial growth stage the film grows in the form of needle-like islands with a high aspect ratio and, subsequently, when a certain coverage is reached, terraced mounds of 6P are formed. It is shown that this ‘certain coverage’ strongly depends on the substrate temperature and that the morphology of the film can be tailored easily by changing the surface temperature. Combined XPS and TDS investigations were carried out to obtain information on the stability of these films. It is shown that films grown at low temperature (90 K) rearrange during heating and this rearrangement could also be made visible by AFM.

Frank, P.; Winkler, A.

2008-03-01

369

Passivation of Organic Light-Emitting Diodes by the Plasma Polymerized para-Xylene Thin Film  

NASA Astrophysics Data System (ADS)

Plasma-polymerized para-xylene (PPpX) thin films deposited by plasma-enhanced chemical vapor deposition (PECVD) were used to passivate the organic light-emitting diodes (OLEDs). For OLEDs, indium-tin-oxide, N,N\\prime-diphenyl-N,N\\prime-bis(3-methylphenyl)-1,1?-diphenyl-4,4?-diamine, tris-8-hydroxyquinoline aluminum and aluminum were used as the anode, the hole transport layer, the emitting layer and the cathode, respectively. The OLED device with the PPpX passivation film (passivated device) showed similar electrical and optical characteristics to those of the OLED device without the PPpX passivation film (control device), indicating that the PECVD process did not degrade the performance of the OLEDs notably. Although PPpX passivation did not enhance the lifetime of the OLEDs significantly, the PPpX film was, to some extent, effective as a passivation layer of the OLEDs. The lifetime of the passivated device was two times longer than that of the control device. Passivation of OLEDs with PPpX films also suppressed the growth of dark spots. The density and size of dark spots of the passivated device were much smaller than those of the control device.

Kho, Samil; Cho, Daeyong; Jung, Donggeun

2002-11-01

370

Kinetic decomposition of ozone and para-chlorobenzoic acid (pCBA) during catalytic ozonation.  

PubMed

The decomposition of ozone and para-chlorobezoic acid (pCBA) using ozone and ozone/goethite were investigated under various conditions to define the characteristics of ozonation and catalytic ozonation. A continuous analysis of the kinetics of the reaction between ozone and pCBA was established, and the decay rate of ozone and pCBA with/without goethite was determined. The decay rate of ozone in the presence of goethite was much higher than in the absence of goethite and was strongly pH dependent due to the reactivities of ozone with the three surface species ( identical with FeOH(2)(+), identical with FeOH, identical with FeO(-)) of goethite. The removal pattern of ionized pCBA at different pHs agreed well with the instantaneous ozone demand. The removal rate of pCBA and instantaneous ozone demand with/without t-butanol at different pHs were compared to elucidate the reaction mechanisms associated with the three reaction sites: (i) on the surface of the catalyst, (ii) at the catalyst-solution interface, and (iii) in the bulk solution. PMID:15142789

Park, Jong-Sup; Choi, Heechul; Cho, Jaewon

2004-05-01

371

Refresher training and continuing education for para-medical ophthalmic assistants.  

PubMed

This paper describes a refresher training and continuing education programme in clinical and community ophthalmology for para-medical ophthalmic assistants (PMOAs) conducted by the Lions Aravind Institute of Community Ophthalmology. The course participants included 60 PMOAs working either in district hospitals, primary health centres or mobile units from the districts in Maharashtra. Each training programme was spread over 43 hours in 4 days and included lectures, practical demonstrations, and hands-on training in the outpatient, inpatient, and operation theatre of the training institution. Participants were given exposure to outreach activities in an eye camp and a satellite eye centre resembling a district hospital. The PMOAs found the training to be useful and it was seen that areas like patient counselling, instrument and equipment maintenance, and assistance in the operation theatre for newer surgical procedures which were lacking in the basic training were fulfilled in this training programme. Regional Institutes of Ophthalmology, upgraded medical colleges, and other eye-care institutions which have facilities and manpower could organise similar refresher and continuing education programmes for PMOAs so that they could be utilised more efficiently in the blindness-control activities in the country. PMID:16130288

Shamanna, B R; Rao, R S; Premarajan, K C; Saravanan, S; Thulasiraj, R D; Venkataswamy, G

1999-03-01

372

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

373

Origin of the low-energy emission band in epitaxially grown para-sexiphenyl nanocrystallites.  

PubMed

A comparative study of steady-state and time-resolved photoluminescence of para-sexiphenyl (PSP) films grown by organic molecular beam epitaxy (OMBE) and hot wall epitaxy (HWE) under comparable conditions is presented. Using different template substrates [mica(001) and KCl(001) surfaces] as well as different OMBE growth conditions has enabled us to vary greatly the morphology of the PSP crystallites while keeping their chemical structure virtually untouched. We prove that the broad redshifted emission band has a structure-related origin rather than being due to monomolecular oxidative defects. We conclude that the growth conditions and type of template substrate impacts substantially on the film morphology (measured by atomic force microscopy) and emission properties of the PSP films. The relative intensity of the defect emission band observed in the delayed spectra was found to correlate with the structural quality of PSP crystallites. In particular, the defect emission has been found to be drastically suppressed when (i) a KCl template substrate was used instead of mica in HWE-grown films, and (ii) in the OMBE-grown films dominated by growth mounds composed of upright standing molecules as opposed to the films consisting of crystallites formed by molecules lying parallel to the substrate. PMID:19256621

Kadashchuk, A; Schols, S; Heremans, P; Skryshevski, Yu; Piryatinski, Yu; Beinik, I; Teichert, C; Hernandez-Sosa, G; Sitter, H; Andreev, A; Frank, P; Winkler, A

2009-02-28

374

Oxidation of ortho- and para-aminobenzoic acid. A pulse radiolysis- and gamma radiolysis study  

NASA Astrophysics Data System (ADS)

The oxidation of anthranilic acid (ortho-aminobenzoic acid, ANA) and para-aminobenzoic acid (PABA) by •OH, N3• and O•- in basic solution was studied by pulse radiolysis. The kinetic and spectroscopic characteristics of the intermediate transients were determined. For ANA the site attack of the OH radicals was established to be ˜50% on the -NH2 moiety and ˜50% on the aromatic ring with an overall rate constant k(•OH+ANA)=(5.5×109) dm3 mol-1 s-1. The rate constant of PABA was k(•OH+PABA)=8×109 dm3 mol-1 s-1. The OH-adducts of both compounds showed a first order decay of 0.8×105 and 1.2×105 s-1, respectively, whereby the corresponding anilino-radicals were formed. The rate constant of ANA with solvated electrons was k(e-aq+ANA)=2.9×109 dm3 mol-1 s-1. The radiation induced decomposition of both substrates was studied by gamma radiolysis as a function of the absorbed dose. They exhibited a distinct radiation resistance, the initial degradation yields were ˜0.16 ?mol J-1, i.e. only 28% of the •OH radicals contributed to their decomposition. The hydroxylation process was of minor importance, the yield of hydroxylated aminobenzoic acids was?0.01 ?mol J-1.

Solar, Sonja; Getoff, Nikola; Zona, Robert; Solar, Wolfgang

2011-09-01

375

Coarse-grain model of the benzene ring with para-substituents in the molecule.  

PubMed

A new two-site coarse-grain model of the benzene ring with substituents in the para-position is proposed for use with multiscale simulations. The model uses a modified Lennard-Jones potential and introduces an additional shifting parameter to the description of the atom-atom interactions. Furthermore, the model separates sets of parameters of Van-der-Waals interactions into inter- and intramolecular. The shifting parameter is specified separately for each pair of atom types for both inter- and intramolecular interactions. The model itself consists of two superatoms. It allows for high speed calculations, "remembers" the benzene ring orientation in multiscale simulations, and can be used together with well-known sets of "united atoms" potentials. This model was tested on p-xylene, 1-ethyl-4-methylbenzene, and 1-methyl-4-propylbenzene. Structural properties for all three substances in the full-atomic model, the "united atoms" model, and the suggested coarse-grained model are discussed. The results demonstrate that the local structure derived from the coarse-grained model is very similar to that derived from the "united atoms" model. PMID:22401424

Neverov, Vladimir S; Komolkin, Andrei V

2012-03-01

376

Virilizing para-adrenocortical adenoma associated with idiopathic-acquired generalized anhidrosis in an adolescent girl.  

PubMed

Adrenocortical tumors are rare in childhood and adolescence. Virilization, alone or in combination with signs of overproduction of other adrenal hormones, is the most common clinical presentation. Here we report an unusual case of an African-American female adolescent presenting with idiopathic acquired generalized anhidrosis, dysregulation of body temperature, absence of adult body odor and dry skin in the face of a virilizing para-adrenocortical adenoma. Virilization signs regressed soon after removal of the tumor, but normalization of the 3alpha-androstenediol glucuronide (3alpha-AG) took longer compared to other measurable androgens; accompanied by anhidrosis. The association of remitting anhidrosis with normalized levels of 3alpha-AG suggests it might be a possible mechanism for anhidrosis. High 3alpha-AG levels might implicate the increased peripheral conversion of weak pro-androgens with different biochemical structure. We recommend obtaining 3alpha-AG beside other androgens in virilized patients with atypical dermatological symptoms in the face of hyperandrogenism. PMID:21648301

Gumus, Pinar; Luquette, Mark; Haymon, Marie Louise; Valerie, Evans; Morales, Jaime; Vargas, Alfonso

2011-01-01

377

From clusters to fibers: parameters for discontinuous para-hexaphenylene thin film growth.  

PubMed

All relevant steps of discontinuous thin film growth of para-hexaphenylene on muscovite mica (0 0 1) from wetting layer over small and large clusters to nanofibers are observed and investigated in detail by a combined polarized fluorescence and atomic force microscopy study. From a variation of film thickness and surface temperature, we determine effective activation energies for cluster growth of 0.17 eV, for nanofiber length growth of 0.46 eV, for width growth of 0.19 eV, and for height growth of 0.07 eV. The corresponding exponential prefactors for the nanofiber growth are 1 x 10(9), 6 x 10(4), and 3 x 10(2) nm. Polarized fluorescence studies reveal that nanofibers grow along the grooves of the mica surface and that they do not change direction if they cross an even number of mica surface steps, while they change direction by 120 degrees for an odd number of steps. These results are taken as an input for a model of the unidirectional growth process on mica. Absolute parameters allowing one to grow nanofibers of predetermined morphology via organic molecular beam epitaxy are also given. PMID:18315074

Kankate, Laxman; Balzer, Frank; Niehus, Horst; Rubahn, Horst-Günter

2008-02-28

378

About long-lived nuclear spin states involved in para-hydrogenated molecules.  

PubMed

This study deals with a spin system constituted of three nonequivalent protons, two of them originating from para-hydrogen (p-H(2)) after a hydrogenation reaction carried out in the earth magnetic field. It is shown that three singlet states are created provided indirect (J) couplings exist between the three spins, implying hyperpolarization transfer toward the third spin. Upon insertion of the sample in the NMR (Nuclear Magnetic Resonance) high field magnet, the following events occur: (i) the longitudinal two-spin orders which are parts of the singlet states survive; (ii) the other two terms (of these singlet states) tend to be destroyed by magnetic field gradients but at the same time are partly converted into differences of longitudinal polarizations. Nuclear spin relaxation is studied by appropriate NMR measurements when evolution takes place in the high field magnet or in the earth field. In the former case, relaxation is classical although complicated by numerous relaxation rates associated with both longitudinal two-spin orders and longitudinal polarizations. In the latter case, an equilibration between the singlet states first occur, their disappearance being thereafter driven by relaxation rates which remain very small because of the absence of any dipolar contribution. Thus, even in the case of a three-spin system, long-lived states exist; this unexpected property could be very useful for many applications. PMID:17263430

Canet, Daniel; Bouguet-Bonnet, Sabine; Aroulanda, Christie; Reineri, Francesca

2007-02-01

379

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

2011-02-23

380

OV-Wav: um novo pacote para análise multiescalar em astronomia  

NASA Astrophysics Data System (ADS)

Wavelets e outras formas de análise multiescalar têm sido amplamente empregadas em diversas áreas do conhecimento, sendo reconhecidamente superiores a técnicas mais tradicionais, como as análises de Fourier e de Gabor, em certas aplicações. Embora a teoria dos wavelets tenha começado a ser elaborada há quase trinta anos, seu impacto no estudo de imagens astronômicas tem sido pequeno até bem recentemente. Apresentamos um conjunto de programas desenvolvidos ao longo dos últimos três anos no Observatório do Valongo/UFRJ que possibilitam aplicar essa poderosa ferramenta a problemas comuns em astronomia, como a remoção de ruído, a detecção hierárquica de fontes e a modelagem de objetos com perfis de brilho arbitrários em condições não ideais. Este pacote, desenvolvido para execução em plataforma IDL, teve sua primeira versão concluída recentemente e está sendo disponibilizado à comunidade científica de forma aberta. Mostramos também resultados de testes controlados ao quais submetemos os programas, com a sua aplicação a imagens artificiais, com resultados satisfatórios. Algumas aplicações astrofísicas foram estudadas com o uso do pacote, em caráter experimental, incluindo a análise da componente de luz difusa em grupos compactos de galáxias de Hickson e o estudo de subestruturas de nebulosas planetárias no espaço multiescalar.

Pereira, D. N. E.; Rabaça, C. R.

2003-08-01

381

Health promotion programs related to the Athens 2004 Olympic and Para Olympic games  

PubMed Central

Background The Olympic Games constitute a first-class opportunity to promote athleticism and health messages. Little is known, however on the impact of Olympic Games on the development of health-promotion programs for the general population. Our objective was to identify and describe the population-based health-promotion programs implemented in relation to the Athens 2004 Olympic and Para Olympic Games. Methods A cross-sectional survey of all stakeholders of the Games, including the Athens 2004 Organizing Committee, all ministries of the Greek government, the National School of Public Health, all municipalities hosting Olympic events and all official private sponsors of the Games, was conducted after the conclusion of the Games. Results A total of 44 agencies were surveyed, 40 responded (91%), and ten (10) health-promotion programs were identified. Two programs were implemented by the Athens 2004 Organizing Committee, 2 from the Greek ministries, 2 from the National School of Public Health, 1 from municipalities, and 3 from official private sponsors of the Games. The total cost of the programs was estimated at 943,000 Euros; a relatively small fraction (0.08%) of the overall cost of the Games. Conclusion Greece has made a small, however, significant step forward, on health promotion, in the context of the Olympic Games. The International Olympic Committee and the future hosting countries, including China, are encouraged to elaborate on this idea and offer the world a promising future for public health.

Soteriades, Elpidoforos S; Hadjichristodoulou, Christos; Kremastinou, Jeni; Chelvatzoglou, Fotini C; Minogiannis, Panagiotis S; Falagas, Matthew E

2006-01-01

382

Seizure of illicitly produced para-fluorofentanyl: quantitative analysis of the content of capsules and tablets.  

PubMed

A gas chromatography/mass spectrometry (GC/MS) method for the quantification of para-fluorofentanyl (pFF) in powder and powdered samples was developed and validated. The method was applied on a seizure of capsules and tablets, that had been confiscated at an illicit production site in the Netherlands. The investigated capsules and tablets contained pFF in the range of 33.8-408.7 microg. As caffeine was detected as being an adulterant, a HPLC/UV method for the quantification of caffeine in capsules and tablets was also validated and applied. Caffeine was detected in the range of 25.6-108 mg per capsule or tablet. Based on an extrapolation of pharmacological and toxicological data of fentanyl, it can be argued that the highest detected single dose of pFF could be lethal, when administered orally. However, the large variability of the doses observed for pFF could mislead abusers, potentially leading to multiple doses and thus overdosing. PMID:12615244

de Boer, D; Goemans, W-P J; Ghezavat, V R; van Ooijen, R D; Maes, R A A

2003-03-10

383

Treatment of post-catheterization femoral artery pseudo-aneurysm with para-aneurysmal saline injection.  

PubMed

Femoral artery pseudoaneurysm is a common complication associated with cardiac catheterization procedures. Ultrasound-based techniques (e.g., mechanical compression, thrombin injection) and open surgical intervention are frequently used in the management of pseudoaneurysm. The investigators report their prospective experience with a novel method for the treatment of pseudoaneurysm after cardiac catheterization using ultrasound-guided, para-aneurysmal injection of physiologic saline. Sixty-four consecutive patients with pseudoaneurysms after cardiac catheterization were treated using normal saline (0.9% sodium chloride 25 to 60 ml) injected into the tissue surrounding the tract connecting the pseudoaneurysm with the femoral artery, followed by manual pressure of short duration. In none of the patients was concomitant antithrombotic therapy (aspirin [n = 63], clopidogrel [n = 45], unfractionated or low-molecular-weight heparin [n = 23], and warfarin [n = 5]) discontinued during the closure attempt. Fifty-nine of the 64 pseudoaneurysms (92%) were successfully occluded using saline injection. In 5 patients in whom saline injection failed, the pseudoaneurysms were successfully treated with thrombin injection (n = 4) or ultrasound-guided compression (n = 1). In all 64 patients, pseudoaneurysm closure was confirmed by ultrasound at 24 hours. The procedure was very well tolerated by the patients, and no side effects or complications were noted. In conclusion, ultrasound-guided saline injection affords a simple, safe, and effective alternative treatment for the closure of postcatheterization pseudoaneurysms. PMID:18471452

Finkelstein, Ariel; Bazan, Shmuel; Halkin, Amir; Herz, Izhak; George, Jacob; Miller, Hylton I; Keren, Gad; Banai, Shmuel

2008-03-17

384

Force field of para- and metabenzyne diradicals: a multireference coupled-cluster study.  

PubMed

The reduced multireference (RMR) coupled-cluster (CC) method with singles and doubles (RMR CCSD) that exploits a modest size MR CISD wave function as an external source for a small subset of the most important (primary) triples and quadruples to account for quasidegeneracy due to a MR nature of the states considered, as well as its RMR CCSD(T) version corrected for the secondary triples, are employed to compute fundamental vibrational frequencies for the para- and metabenzene diradicals. A comparison is made with the available experimental data and with other methods, namely, the state selective or Mukherjee CCSD and completely renormalized, size-extensive version of CCSD(T), the so-called CR-CC(2,3), methods. Both the restricted Hartree-Fock and multiconfiguration self-consistent-field (MCSCF) molecular orbitals (MOs) are employed. The four-reference RMR CCSD using MCSCF MOs gives particularly satisfactory results. The breakdown of CCSD(T) and shortcomings of some other approaches are pointed out and the role of invariance with respect to MO rotation is analyzed. Correlation with triplet-singlet splittings is also pointed out. PMID:20331277

Li, Xiangzhu; Paldus, Josef

2010-03-21

385

Tetrathiafulvalene-oligo(para-phenyleneethynylene) conjugates: formation of multiple mixed-valence complexes upon electrochemical oxidation.  

PubMed

Short monodisperse oligo- (para-phenyleneethynylene) (pOPE) units bearing laterally attached tetrathio-substituted tetrathiofulvalene (TTF) units have been synthesised from functionalised aromatic building blocks by using the Sonogashira cross-coupling methodology. The unusual redox properties of these TTF-pOPE conjugates were observed by employing electrochemical methods, such as cyclic voltammetry and exhaustive electrolysis. We found that formally one half of the TTF units in the pOPE monomer 1, dimer 2, and trimer 3 (with 2, 4, and 6 TTF units, respectively) are electrochemically silent during the first-step oxidation at 0.49?V. We propose the formation of persistent mixed-valence complexes from the TTF and TTF(+·) units present in an equal ratio. Such mixed-valence dyads (single or multiple in the partially oxidised 1-3) exhibit an unusual stability towards oxidation until the potential of the second oxidation at 0.84?V is achieved. This finding suggests that below this potential the oxidation of the respective mix-valence complexes is extremely slow. PMID:23495131

Lipnická, Šárka; B?lohradský, Martin; Kolivoška, Viliam; Pospíšil, Lubomír; Hromadová, Magdaléna; Pohl, Radek; Chocholoušová, Jana Vacek; Vacek, Jaroslav; Fiedler, Jan; Stará, Irena G; Starý, Ivo

2013-03-13

386

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

387

Origin of the low-energy emission band in epitaxially grown para-sexiphenyl nanocrystallites  

NASA Astrophysics Data System (ADS)

A comparative study of steady-state and time-resolved photoluminescence of para-sexiphenyl (PSP) films grown by organic molecular beam epitaxy (OMBE) and hot wall epitaxy (HWE) under comparable conditions is presented. Using different template substrates [mica(001) and KCl(001) surfaces] as well as different OMBE growth conditions has enabled us to vary greatly the morphology of the PSP crystallites while keeping their chemical structure virtually untouched. We prove that the broad redshifted emission band has a structure-related origin rather than being due to monomolecular oxidative defects. We conclude that the growth conditions and type of template substrate impacts substantially on the film morphology (measured by atomic force microscopy) and emission properties of the PSP films. The relative intensity of the defect emission band observed in the delayed spectra was found to correlate with the structural quality of PSP crystallites. In particular, the defect emission has been found to be drastically suppressed when (i) a KCl template substrate was used instead of mica in HWE-grown films, and (ii) in the OMBE-grown films dominated by growth mounds composed of upright standing molecules as opposed to the films consisting of crystallites formed by molecules lying parallel to the substrate.

Kadashchuk, A.; Schols, S.; Heremans, P.; Skryshevski, Yu.; Piryatinski, Yu.; Beinik, I.; Teichert, C.; Hernandez-Sosa, G.; Sitter, H.; Andreev, A.; Frank, P.; Winkler, A.

2009-02-01

388

Conservation of Hox/ParaHox-related genes in the early development of a cnidarian.  

PubMed

To clarify the relationship between axial patterning in cnidarians and bilaterians, we have investigated the embryonic development of the hydrozoan Podocoryne carnea. The expression of Hox-like homeobox genes was analyzed by RT-PCR and in situ hybridization. Cnox1-Pc, an anterior Hox gene, is a maternal message. It is present throughout larval development, first weakly in all blastomeres and later restricted mostly to the anterior pole of the planula. Gsx, an anterior ParaHox gene, is first seen in the anterior endoderm but also extends into posterior regions. Cnox4-Pc, an orphan Hox-like gene, is expressed in the egg as a ring-shaped cloud around the germinal vesicle. After fertilization, the message remains in most animal blastomeres. When the embryo elongates in late blastula, staining is restricted to a few cells at the posterior pole where gastrulation will start. However, once gastrulation starts, the Cnox4-Pc signal disappears and is absent in later stages of larval development. Phylogenetic analysis shows that not all cnidarian Hox-like genes have recognizable orthologues in bilaterian groups. However, the expression analysis of Cnox1-Pc and Gsx correlates to some extent with the expression pattern of cognate genes of bilaterians, confirming the conservation of genes involved in organizing animal body plans and their putative common ancestral origin. PMID:11456446

Yanze, N; Spring, J; Schmidli, C; Schmid, V

2001-08-01

389

USO DE LA WEB PARA EL APOYO DEL PROCESO ENSEÑANZA-APRENDIZAJE EN LA DISCIPLINA SANIDAD VEGETAL EN LA CARRERA DE INGENIERÍA AGRONÓMICA  

Microsoft Academic Search

Este artículo resume la utilización de una página web como complemento de los medios tradicionales (impresos y audiovisuales), empleado para el desarrollo del proceso de enseñanza-aprendizaje de la disciplina Sanidad Vegetal en la formación de ingenieros agrónomos. Como principales resultados se contribuye al logro de las habilidades necesarias propias de la disciplina, las cuales son indispensables para el futuro profesional

Carlos Pupo Feria; Gladia González Ramírez

2010-01-01

390

CARACTERIZAÇÃO GEOTÉCNICA EXPEDITA DO GRANITO DO PORTO PARA FINS DE ESCAVAÇÃO DE TÚNEIS SWIFT GEOTECHNICAL CHARACTERIZATION OF OPORTO GRANITE FOR TUNNELING EXCAVATION  

Microsoft Academic Search

RESUMO Os critérios sugeridos por diversos autores para a caracterização geotécnica dos maciços rochosos não são de fácil e expedita aplicação, visto que nela intervêm várias propriedades geotécnicas que quantificam características geológicas, geomecânicas e geofísicas dos maciços e rochas constituintes e a determinação de tais parâmetros é difícil e morosa. O presente artigo tem por objectivo apontar critérios para uma

Dinis da Gama

391

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

392

QUANTOS PONTOS DE CONCORDÂNCIA SÃO NECESSÁRIOS PARA SE OBTER UMA IDENTIFICAÇÃO ODONTOLEGAL POSITIVA? HOW MANY POINTS OF CONCORDANCE ARE NECESSARY TO OBTAIN A POSITIVE FORENSIC DENTAL IDENTIFICATION?  

Microsoft Academic Search

RESUMO O presente trabalho representa um estudo de caso sobre identificação humana com técnica comparativa, por meio de um método odontolegal, em que se discutem os aspectos de quantidade e qualidade de pontos de concordância necessários para se obter uma identificação positiva. É ressaltado que, apesar de alguns trabalhos estabelecerem um mínimo de doze pontos convergentes, assim como preconizado para

Rhonan Ferreira da Silva; Mauro Machado do Prado; Henrique César; Marçal de Oliveira; Eduardo Daruge Júnior

393

CAIXAS INCUBADORAS PARA A FORMAÇÃO E OBSERVAÇÃO DE COLÔNIAS DE ABELHAS SEM FERRÃO (Apidae: Meliponina) INCUBATOR HIVES FOR FORMATION AND OBSERVATION OF STINGLESS BEES (Apidae: Meliponina) COLONIES  

Microsoft Academic Search

RESUMO: Diversos estudos sobre biologia e manejo de meliponíneos têm utilizado caixas que mantém colônias em condição ideal de temperatura, aproximadamente 30°C, para incubação das crias. O presente estudo descreve um sistema de caixas incubadoras, elaborado com a finalidade de auxiliar no desenvolvimento de novas colônias, formadas com pouco material biológico, visando à produção de ninhos para a meliponicultura, bem

Luciano COSTA; Giorgio Cristino VENTURIERI

394

De las capacidades dinámicas como enfoque de la estrategia a la integración de competencias para la construcción de un entorno colaborativo Univ - Emp  

Microsoft Academic Search

Este artículo intenta mostrar la importancia de avanzar de un enfoque de capacidades dinámicas a uno de competencias, para construir una estrategia de entornos colaborativos que permita aprovechar los esfuerzos y las oportunidades de la relación universidad- empresa. Para tal fin, el documento está organizado en tres partes: la primera, es una revisión amplia de las perspectivas desde las cuales

Patricia Roncancio R

2011-01-01

395

Involvement of the Azorhizobial Chromosome Partition Gene (parA) in the Onset of Bacteroid Differentiation during Sesbania rostrata Stem Nodule Development ? †  

PubMed Central

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.

Liu, Chi-Te; Lee, Kyung-Bum; Wang, Yu-Sheng; Peng, Min-Hua; Lee, Kung-Ta; Suzuki, Shino; Suzuki, Tadahiro; Oyaizu, Hiroshi

2011-01-01

396

Electron diffraction study of meta- and para-fluoronitrobenzene using results from quantum chemical calculations. Trends in the carbon–halogen bond length found in ortho-, meta- and para-halonitrobenzenes (Halo=F, Cl, Br, I)  

Microsoft Academic Search

The molecular geometry of meta- and para-fluoronitrobenzene has been determined by gas electron diffraction and quantum chemical calculations using HF, MP2 and DFT, and 6-311G**, 6-311++G** and cc-pVTZ basis sets. The obtained geometrical parameters (rg, in Å, ?? in degrees) for meta-fluoronitrobenzene are: r(C–C)av=1.397(4), r(N–O)av=1.227(3), r(C–N)=1.484(3), r(C–F)=1.333(8), r(C–H)av=1.107(16), ?C1C2N=118.3(6), ?C5C6F=120.6(24), ?ONO=125.3(37), ?C1C2C3=122.9(24), ?C3C4C5=119.2(18) and ?(C–N)=0 (fixed) and for para-fluoronitrobenzene: r(C–C)av=1.393(2),

Igor F. Shishkov; Lyudmila V. Khristenko; Svein Samdal; Snefrid Gundersen; Hans V. Volden; Lev V. Vilkov

2004-01-01

397

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

398

A review of inhalation toxicology studies with para-aramid fibrils.  

PubMed

The paper summarizes the results of inhalation toxicology studies associated with para-aramid (p-aramid) fibrils. The review is subdivided into two categories: the results of inhalation toxicity studies and mechanistic inhalation studies. Keratin-associated lesions were observed in the lungs of female rats following chronic exposure to high concentrations of p-aramid. These lesions were originally interpreted as cystic keratinizing squamous cell carcinomas (CKSCC). In recent years, this keratinizing lesion has been observed in the lungs of rats with greater regularity in numerous chronic inhalation studies following exposures to a variety of dusts. In an attempt to reach a consensus on an appropriate diagnosis for this lesion, an international panel of pathologists was convened to evaluate the morphological aspects of this lesion. The panel considered that the most appropriate diagnosis for this lesion was 'proliferative keratin cyst' (PKC), the biological potential of the PKC remains controversial, but it appears to be unique to the rat species and has little relevance for humans. Mechanistic studies with p-aramid have demonstrated that acute inhalation of high concentrations of fibrils produces a potent but transient pulmonary inflammatory and cell labelling response. The inhaled fibrils have low durability in the lungs of rats as evidenced by a progressive decrease in median fibre lengths with increasing residence time in the lung. In contrast, in a comparative study, size-separated chrysotile asbestos produced a sustained increase over controls in cellular proliferation responses of terminal airways, parenchyma, subpleural and mesothelial regions.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8526399

Warheit, D B

1995-10-01

399

Genes, enzymes, and regulation of para-cresol metabolism in Geobacter metallireducens.  

PubMed

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; alpha(2)beta(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 alpha subunit of the enzyme was present in two isoforms, suggesting an alphaalpha'beta(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. PMID:17449613

Peters, Franziska; Heintz, Dimitri; Johannes, Jörg; van Dorsselaer, Alain; Boll, Matthias

2007-04-20

400

Long-term health-enhancing physical activity in rheumatoid arthritis - the PARA 2010 study  

PubMed Central

Background People with rheumatoid arthritis (RA) suffer increased risk of disability andpremature mortality. Health-enhancing physical activity (HEPA) could be one importantfactor to reduce this risk. Rising health care costs call for the development and evaluation ofnew modes of rehabilitation, including physical activity in settings outside the health caresystem. Methods/Design This cohort study targets 450 patients with RA that do not currently meet HEPA recommendations, recruited from six hospitals reporting to the Swedish Rheumatology Quality Registers (SRQ). We have developed a two-year real-life intervention program including a minimum of twice-weekly circuit training, moderately intense physical activity the remaining days of the week and group meetings to support behavior change every other week. Our hypothesis is that increased physical activity and exercise will improve perceived health, reduce pain and fatigue, increase muscle function and aerobic capacity, impact psychosocial factors and prevent future cardiovascular events. Research questions regard outcomes, retention rates, dose–response matters and the exploration of responder characteristics. This protocol outlines recruitment procedure, design, assessment methods and the intervention program of the study. Discussion The PARA 2010 project is designed to expand the knowledge on HEPA in RA by a progressive approach regarding population, setting, intervention, time frames and outcome measures. To our knowledge this is the first long-term HEPA program based on Social Cognitive Theory, and performed in a real life environment to demonstrate if this new setting can promote increased and maintained physical activity in people with RA. Trial registration number ISRCTN25539102

2012-01-01

401

Initial stages of a para-hexaphenyl film growth on amorphous mica  

NASA Astrophysics Data System (ADS)

Para-hexaphenyl (6P) molecules were deposited in the submonolayer range on a sputter- modified muscovite mica(001) surface by physical vapor deposition under ultrahigh vacuum conditions. The ultrathin films were investigated in situ by thermal desorption spectroscopy and ex situ by atomic force microscopy. On the sputter-modified amorphous mica surface the 6P molecules form two-dimensional islands of standing molecules. From the island size and capture zone distribution, as well as from the island density as a function of deposition rate and substrate temperature, all relevant parameters, characterizing the nucleation process, could be deduced. The critical island size was determined to be two and/or three molecules. The preexponential factor for surface diffusion of the monomers was determined to be 2 × 1017 s-1. The binding energy of a critical nucleus with i = 3 was found to be 1.5 eV, using the calculated value of 0.02 eV for the diffusion energy barrier. This is in good agreement with our calculations of the binding energy for a critical cluster consisting of three lying molecules. Furthermore, the calculations show that the critical clusters are lying flat on the surface; they transform into islands of standing molecules only after the incorporation of further molecules. The shape of the islands is slightly dendritic at low surface temperature and becomes more dendritic with increasing temperature. This unusual behavior, which is the opposite of the frequently observed temperature dependence of metal islands, is also discussed in some detail.

Potocar, T.; Lorbek, S.; Nabok, D.; Shen, Q.; Tumbek, L.; Hlawacek, G.; Puschnig, P.; Ambrosch-Draxl, C.; Teichert, C.; Winkler, A.

2011-02-01

402

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

403

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

404

Long-term health-enhancing physical activity in rheumatoid arthritis - the PARA 2010 study.  

PubMed

ABSTRACT: BACKGROUND: People with rheumatoid arthritis (RA) suffer increased risk of disability and premature mortality. Health-enhancing physical activity (HEPA) could be one important factor to reduce this risk. Rising health care costs call for the development and evaluation of new modes of rehabilitation, including physical activity in settings outside the health care system. METHODS: This cohort study targets 450 patients with RA that do not currently meet HEPA recommendations, recruited from six hospitals reporting to the Swedish Rheumatology Quality Registers (SRQ). We have developed a two-year real-life intervention program including a minimum of twice-weekly circuit training, moderately intense physical activity the remaining days of the week and group meetings to support behavior change every other week. Our hypothesis is that increased physical activity and exercise will improve perceived health, reduce pain and fatigue, increase muscle function and aerobic capacity, impact psychosocial factors and prevent future cardiovascular events. Research questions regard outcomes, retention rates, dose-response matters and the exploration of responder characteristics. This protocol outlines recruitment procedure, design, assessment methods and the intervention program of the study. DISCUSSION: The PARA 2010 project is designed to expand the knowledge on HEPA in RA by a progressive approach regarding population, setting, intervention, time frames and outcome measures. To our knowledge this is the first long-term HEPA program based on Social Cognitive Theory, and performed in a real life environment to demonstrate if this new setting can promote increased and maintained physical activity in people with RA. Trial registration number ISRCTN25539102. PMID:22656861

Nordgren, Birgitta; Fridén, Cecilia; Demmelmaier, Ingrid; Bergström, Gunnar; Opava, Christina H

2012-06-01

405

OrthoParaMap: Distinguishing orthologs from paralogs by integrating comparative genome data and gene phylogenies  

PubMed Central

Background In eukaryotic genomes, most genes are members of gene families. When comparing genes from two species, therefore, most genes in one species will be homologous to multiple genes in the second. This often makes it difficult to distinguish orthologs (separated through speciation) from paralogs (separated by other types of gene duplication). Combining phylogenetic relationships and genomic position in both genomes helps to distinguish between these scenarios. This kind of comparison can also help to describe how gene families have evolved within a single genome that has undergone polyploidy or other large-scale duplications, as in the case of Arabidopsis thaliana – and probably most plant genomes. Results We describe a suite of programs called OrthoParaMap (OPM) that makes genomic comparisons, identifies syntenic regions, determines whether sets of genes in a gene family are related through speciation or internal chromosomal duplications, maps this information onto phylogenetic trees, and infers internal nodes within the phylogenetic tree that may represent local – as opposed to speciation or segmental – duplication. We describe the application of the software using three examples: the melanoma-associated antigen (MAGE) gene family on the X chromosomes of mouse and human; the 20S proteasome subunit gene family in Arabidopsis, and the major latex protein gene family in Arabidopsis. Conclusion OPM combines comparative genomic positional information and phylogenetic reconstructions to identify which gene duplications are likely to have arisen through internal genomic duplications (such as polyploidy), through speciation, or through local duplications (such as unequal crossing-over). The software is freely available at .

Cannon, Steven B; Young, Nevin D

2003-01-01

406

Reversible dissociation of cortisol-transcortin complex by sodium para-chloromercuribenzoate.  

PubMed

Mercurials are considered as sulphydryl group specific reagents and one of them, sodium para-chloromercuribenzoate (PCMB), is currently used for SH titration. It has been shown that cellular steroid receptors are reversibly inactivated by mercurials even when the binding site is occupied by the steroid (Coty, W.A. (1980) J. Biol. Chem. 255, 8035-8037). This is a striking difference with alkylating SH reagents such as iodoacetic acid or N-ethylmaleimide, since these reagents inactivate only steroid-free receptors. In order to explain this discrepancy, we tested, in the present study, the specificity of PCMB on a blood plasma steroid binding protein: human transcortin. This protein presents the advantage, over cellular receptors, of being well characterized and to be available in a pure state. The transcortin-cortisol complex was also reversibly inactivated by PCMB when the reaction was carried out at a high excess of reagent over protein; such conditions are those previously used with steroid receptors. The reversibility was obtained not only with a reducing agent (dithiothreitol) but also with EDTA, which suggests a poor stability of the protein mercurial bond and therefore a nonspecific action. The decrease of activity was the result of a loss of binding sites and Scatchard plot analysis did not reveal any detectable decrease of the affinity constant for cortisol. Transcortin possesses two SH groups per molecule, one of these being buried in native conformation. After blockage of the accessible SH group by aminoethylation, transcortin kept the same activity, but when this aminoethylated transcortin was incubated with PCMB a loss of activity was obtained, although the residual buried SH group was again titrable with Ellman's reagent. Therefore, we can conclude that the action of PCMB on proteins must be interpreted with precaution, since it can induce an inactivation that is SH-independent. PMID:6419776

Le Gaillard, F; Azam, H; Favre, G; Dautrevaux, M

1983-12-28

407

Nucleophilic substitution reactions of trans-4-(para-substituted phenoxy)-3-buten-2-ones  

SciTech Connect

Reactions of trans-4-(para-substituted phenoxy)-3-buten-2 ones (1-6) with primary amines to give 4-alkylamino-3-buten-2-ones in water are characterized by (1) rates which are first order in amine and 1-6, (2) a Hammett type rho* = 0.11 for reactions of 1-6 with aminoethanol, (3) ..beta../sub nuc/ = 0.37 for reactions of 4-(p-anisoxy)-3-buten-2-one (1) with ethyl glycinate, trifluoroethylamine, 2-ethoxyethylamine, 2-aminoethanol, and n-butylamine, (4) a deuterium solvent kinetic isotope effect k/sub 2/(H/sub 2/O)/k/sub 2/(D/sub 2/O) = 0.98 for reaction of 1 with 2-aminoethanol, and (5) a Ritchie N/sup +/ coefficient of 1 +- 0.2 for reactions of 1 with imidazole, ethyl glycinate, n-butylamine, and hydroxide ion. Reactions of thiols with the title compounds give 4-alkyl-thio-3-buten-2-ones at low concentrations of thiol and 4,4-dialkylthiobutan-2-ones at high concentrations of thiols. The former reactions are characterized by (1) rates which are first order in thiolate anion and 1-6 and (2) rho* = 0.14 for reactions of 1,4-(p-chlorophenoxy)-3-buten-2-one (4), and 4-(p-nitrophenoxy)-3-buten-2-one (6) with N-acetylcysteine. These data support an addition-elimination reaction with nucleophilic attack rate determining. The kinetics of the reactions of 1 and 4 with morpholine and N-methylaminoethanol appear to provide evidence for the partitioning of the putative 1- and 4-amine addend between 1 and 4 and products. 2 figures, 3 tables.

Lartey, P.A.; Fedor, L.

1979-11-21

408

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

409

Ortho-Para Transition Rate in {mu}-Molecular Hydrogen and the Proton's Induced Pseudoscalar Coupling g{sub p}  

SciTech Connect

We report a measurement of the ortho-para transition rate in the p{mu}p molecule. The experiment was conducted at TRIUMF via the measurement of the time dependence of the 5.2 MeV neutrons from muon capture in liquid hydrogen. The measurement yielded an ortho-para rate {lambda}{sub op}=(11.1{+-}1.7{+-}(0.9/0.6))x10{sup 4} s{sup -1}, which is substantially larger than the earlier result of Bardin et al. The result has striking implications for the proton's induced pseudoscalar coupling g{sub p}, changing the value of g{sub p} obtained from the most precise ordinary muon capture measurement from 10.6{+-}2.7 to 0.8{+-}2.8, and from the sole radiative muon capture measurement from 12.2{+-}1.1 to 10.6{+-}1.2, bringing the latter result closer to theoretical predictions.

Clark, J.H.D.; Armstrong, D.S.; King, P.M. [College of William and Mary, Williamsburg, Virginia 23187 (United States); Gorringe, T.P.; Tripathi, S.; Zolnierczuk, P.A. [University of Kentucky, Lexington, Kentucky 40506 (United States); Hasinoff, M.D.; Stocki, T.J. [University of British Columbia, Vancouver, British Columbia, V6T 1Z1 (Canada); Wright, D.H. [TRIUMF, Vancouver, British Columbia, V6T 2A3 (Canada)

2006-02-24

410

Caulerprenylols A and B, two rare antifungal prenylated para-xylenes from the green alga Caulerpa racemosa.  

PubMed

Two new prenylated para-xylenes, named caulerprenylols A (1) and B (2), were isolated from the green alga Caulerpa racemosa, collected from the Zhanjiang coastline, China. The structures of the two metabolites were elucidated on the basis of detailed spectroscopic analysis. This is the first report of prenylated para-xylenes from marine algae and from marine organisms as well. Moreover, caulerprenylol B (2) is also characterized by an uncommon indane ring system. In in vitro bioassays, the new compounds exhibited a broad spectrum of antifungal activity against Candida glabrata (537), Trichophyton rubrum (Cmccftla), and Cryptococcus neoformans (32609) with MIC80 values between 4 and 64 ?g/mL when compared to amphotericin B (MIC80 values of 2.0, 1.0, and 4.0 ?g/mL, respectively) as a positive control and showed no growth inhibition activity against the tumor cells HL60 and A549. PMID:23548547

Liu, Ai-Hong; Liu, Ding-Quan; Liang, Tong-Jun; Yu, Xiao-Qing; Feng, Mei-Tang; Yao, Li-Gong; Fang, Yi; Wang, Bin; Feng, Li-Hua; Zhang, Min-Xian; Mao, Shui-Chun

2013-03-19

411

Infrared Space Observatory Observations toward the Reflection Nebula NGC 7023: A Nonequilibrium Ortho-to-Para-H_2 Ratio  

NASA Astrophysics Data System (ADS)

We have observed the S(0), S(1), S(2), S(3), S(4), and S(5) rotational lines of molecular hydrogen (H_2) toward the peak of the photodissociation region (PDR) associated with the reflection nebula NGC 7023. The observed H_2 line ratios show that they arise in warm gas with kinetic temperatures ~300-700 K. However, the data cannot be fitted by an ortho-to-para-H_2 ratio of 3. An ortho-to-para (OTP) ratio in the range ~1.5-2 is necessary to explain our observations. This is the first detection of a nonequilibrium OTP ratio measured from the H_2 pure rotational lines in a PDR. The existence of a dynamical PDR is discussed as the most likely explanation for this low OTP ratio.

Fuente, A.; Martín-Pintado, J.; Rodríguez-Fernández, N. J.; Rodríguez-Franco, A.; de Vicente, P.; Kunze, D.

1999-06-01

412

Meta and para effects in the ultrafast excited-state dynamics of the green fluorescent protein chromophores.  

PubMed

Femtosecond transient absorption and fluorescence upconversion experiments have been performed to investigate the photoinduced dynamics of the meta isomer of the green fluorescent protein chromophore, m-HBDI, and its O-methylated derivative, m-MeOBDI, in various solvent mixtures at neutral, acidic, and basic pH. The para isomer, p-HBDI, and its O- and N-methylated derivatives, p-MeOBDI and p-HBDIMe(+), were also studied for comparison. In all cases, fast quenching of the excited S1 state by internal conversion (IC) to the ground state was observed. In the para compounds, IC, presumably promoted by the internal twisting, arises in <1 ps. A similar process takes place in the meta compounds in nonaqueous solvents but with notably slower kinetics. In aqueous solutions, the meta compounds undergo ultrafast intermolecular excited-state proton transfer that competes with isomerization. PMID:18269276

Solntsev, Kyril M; Poizat, Olivier; Dong, Jian; Rehault, Julien; Lou, Yongbing; Burda, Clemens; Tolbert, Laren M

2008-02-13

413

In vitro cell culture, platelet adhesion tests and in vivo implant tests of plasma-polymerized para-xylene films  

NASA Astrophysics Data System (ADS)

Plasma-polymerized para-xylene (PPX) was developed in a previous study by adjusting the process parameters: pulse frequency of the power supply (?p) and para-xylene monomer flow rate (fp). All the obtained PPX films exhibit an amorphous structure and present hydrophobicity (water contact angle ranging from 98.5° to 121.1°), higher film growth rate and good fibroblast cell proliferation. In this study, in vitro tests (fibroblast cell compatibility and platelet adhesion) and an in vivo animal study were performed by using PPX deposited industrial-grade silicone sheets (IGS) and compared with medical-grade silicone ones (MS), which were commonly manufactured into catheters or drainage tubes in clinical use.

Chou, Chia-Man; Yeh, Chou-Ming; Chung, Chi-Jen; He, Ju-Liang

2013-09-01

414

Enhancing Effect of the Endocrine Disruptor para-Nonylphenol on the Generation of Reactive Oxygen Species in Human Blood Neutrophils  

Microsoft Academic Search

Although para-nonylphenol (NP) is known as an endocrine disruptor, the immunologic effect of NP has been poorly analyzed. We found that NP from 5 to 50 µM caused a dose-dependent stimu- latory effect on the generation of reactive oxygen species (ROS) in human blood neutrophils, which was measured by using a chemiluminescence reagent, luminol. Furthermore, ROS-scavenging enzymes such as catalase

Yasuji Okai; Eisuke F. Sato; Kiyoka Higashi-Okai; Masayasu Inoue

2004-01-01

415

In vitro genotoxicity of para-phenylenediamine and its N-monoacetyl or N, N?-diacetyl metabolites  

Microsoft Academic Search

para-Phenylenediamine (PPD), a widely used ingredient of oxidative hair dyes, is converted by human hepatocytes and in the human epidermis, or after topical application to rats, to its N-monoacetylated (MAPPD) and\\/or N,N?-diacetylated (DAPPD) derivatives. We investigated in vitro genotoxic properties of PPD, MAPPD and DAPPD in the Ames test, the micronucleus test (MNT) in human lymphocytes and the mouse lymphoma

Jean-Luc Garrigue; Mark Ballantyne; Tirukalikundram Kumaravel; Mel Lloyd; Gerhard J. Nohynek; David Kirkland; Hervé Toutain

2006-01-01

416

Synthesis of isoxazoles en route to semi-aromatized polyketides: dehydrogenation of benzonitrile oxide-para-quinone acetal cycloadducts.  

PubMed

A variety of highly functionalized polycyclic isoxazoles are prepared by a two-step protocol: (1) 1,3-dipolar cycloaddition of o,o'-disubstituted benzonitrile oxides to para-quinone mono-acetals, then (2) dehydrogenation. The cycloaddition proceeds in a regioselective manner, favouring the formation of the 4-acyl cycloadducts, which are suitable intermediates for the synthesis of semi-aromatized polycyclic targets derived from polyketide type-II biosynthesis. PMID:22595976

Hashimoto, Yoshimitsu; Takada, Akiomi; Takikawa, Hiroshi; Suzuki, Keisuke

2012-05-18

417

Long-term survival after resection of pancreatic ductal adenocarcinoma with para-aortic lymph node metastasis: case report.  

PubMed

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. PMID:23945441

Masui, Toshihiko; Kubota, Toyonari; Aoki, Keiko; Nakanishi, Yasutaka; Miyamoto, Takumi; Nagata, Junko; Morino, Koshiro; Fukugaki, Atsushi; Takamura, Michio; Sugimoto, Shinichi; Onuma, Hideyuki; Tokuka, Atsuo

2013-08-14

418

Molecular dynamics simulations of temperature- and pressure-induced solid–solid phase transitions in crystalline para-terphenyl  

Microsoft Academic Search

Molecular dynamics (MD) simulations of pressure- and temperature-induced solid–solid phase transitions in para-terphenyl have been investigated using Material Studio. Initial simulations were performed using the COMPASS (condensed-phase optimised molecular potentials for atomistic simulation studies) force field to evaluate its ability to model the known temperature and pressure phase boundary between the triclinic and monoclinic crystal phases. Geometry optimisation using the

Bohdan Schatschneider; Eric L. Chronister

2008-01-01

419

Para-Localization Energy (Free-Electron Molecular-Orbital) and Polarographic Half-Wave Potential of some Polynuclear Hydrocarbons  

Microsoft Academic Search

IN a recent communication, Fernandez-Alonso and Domingo1 have reported some numerical disagreements in their para-localization energy calculation with those of Basu2. In Fernandez-Alonso and Domingo's calculation the box dimension for ethylene was taken as equal to one bond-length (as well as half bond-length) more at each end. In Basu's calculation the box dimension was taken to be equal to the

Sadhan Basu; Rama Bhattacharya

1957-01-01

420

A Case of Staphylococcal Tricuspid Valve Endocarditis With Para-Aortic Abscess in a Patient With Bicuspid Aortic Valve  

PubMed Central

Paravalvular abscess is a serious complication of infective endocarditis. The aortic valve and its adjacent ring are more susceptible to abscess formation and paravalvular extension than the mitral valve. A 15-years old patient with bicuspid aortic valve presented with staphylococcal tricuspid valve endocarditis complicated by para-aortic abscess that ruptured into the aortic sinus. We report the clinical, laboratory and echocardiographic features and treatment of this patient and conduct a literature review on this subject.

Kim, Woo Shin; Kang, Seok Hyung; Lee, Shin A; Ryu, Min Sun

2011-01-01

421

A case of staphylococcal tricuspid valve endocarditis with para-aortic abscess in a patient with bicuspid aortic valve.  

PubMed

Paravalvular abscess is a serious complication of infective endocarditis. The aortic valve and its adjacent ring are more susceptible to abscess formation and paravalvular extension than the mitral valve. A 15-years old patient with bicuspid aortic valve presented with staphylococcal tricuspid valve endocarditis complicated by para-aortic abscess that ruptured into the aortic sinus. We report the clinical, laboratory and echocardiographic features and treatment of this patient and conduct a literature review on this subject. PMID:21949535

Kim, Woo Shin; Kang, Seok Hyung; Lee, Shin A; Ryu, Min Sun; Park, Seong-Hoon

2011-08-31

422

Prenatal administration of para-chlorophenylalanine results in suppression of serotonergic system and disturbance of swimming movements in newborn rats  

Microsoft Academic Search

Postnatal development of the spinal cord serotonergic (5-HT) system and of swimming movements were studied in newborn Sprague-Dawley rats, in which the serotonin level in the central nervous system was lowered in the prenatal period. For this purpose, para-chlorophenylalanine (PCPA) (300 mg\\/kg) was administered intraperitoneally to pregnant mother rats on day 8 of gestation, followed by a daily injection of

Katsumi Nakajima; Kiyoji Matsuyama; Shigemi Mori

1998-01-01

423

Metabolite predictions for para-substituted anisoles based on ab initio complete active space self-consistent field calculations  

Microsoft Academic Search

The cytochrome P450 mediated oxidative metabolism of a series of para-substituted anisoles has been examined using ab initio CASSCF (complete active space self-consistent field) calculations. On the basis of these calculations, oxidative metabolites were rationalized using the concept of hydrogen atom abstraction, spin delocalization, and hydroxyl radical recombina- tion, which is believed to govern part of the oxidation and oxygenation

Groot de M. J; Donné-Op Kelder den G. M; Jan N. M. Commandeur; N. P. E. Vermeulen; J. H. Lenthe

1995-01-01

424

Identification of a Point Mutation in the paraType Sodium Channel Gene from a Pyrethroid-Resistant Cattle Tick  

Microsoft Academic Search

To investigate the molecular mechanism of resistance to pyrethroids in the southern cattle tick, Boophilus microplus, we have obtained and sequenced a partial para-homologous sodium channel cDNA from susceptible and pyrethroid-resistant tick strains. A point mutation that results in an amino acid change from Phe to Ile was identified in the highly conserved domain IIIS6 of the homologous sodium channel

Haiqi He; Andrew C Chen; Ronald B Davey; G. Wayne Ivie; John E George

1999-01-01

425

Determination of para-Chloroaniline and Reactive Oxygen Species in Chlorhexidine and Chlorhexidine Associated with Calcium Hydroxide  

Microsoft Academic Search

The aim of this study was to determine whether para-chloroaniline (PCA) and\\/or reactive oxygen species (ROS) are generated by chlorhexidine (CHX) alone or after CHX is mixed with calcium hydroxide at different time points. Mass spectrometry was performed to detect PCA in samples of 0.2% CHX and Ca(OH)2 mixed with 0.2% CHX. High-performance liquid chromatography was used to confirm the

Luiz Eduardo Barbin; Paulo César Saquy; Débora Fernandes Costa Guedes; Manoel Damião Sousa-Neto; Carlos Estrela; Jesus Djalma Pécora

2008-01-01

426

Salud Para Su Corazón-NCLR: A Comprehensive Promotora Outreach Program to Promote Heart-Healthy Behaviors Among Hispanics  

Microsoft Academic Search

This article describes results of year-1 implementation of the Salud Para Su Corazón (Health For Your Heart)—National Council of la Raza (NCLR) promotora (lay health worker) program for promoting heart-healthy behaviors among Latinos. Findings of this community outreach initiative include data from promotora pledges and self-skill behaviors, cardiovascular disease risk factors of Latino families, family heart-health education delivery, and program

Hector Balcazar; Matilde Alvarado; Mary Luna Hollen; Yanira Gonzalez-Cruz; Odelinda Hughes; Esperanza Vazquez; Kristine Lykens

2006-01-01

427

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

428

Preparation and characterization of cross-linked Matrimid ® membranes using para-phenylenediamine for O 2\\/N 2 separation  

Microsoft Academic Search

The cross-linking modification of asymmetric Matrimid membranes with para-phenylenediamine (pPD) has been investigated. The modification was performed by immersing Matrimid membranes in 10% (w\\/v) pPD\\/methanol solution at ambient temperature for certain period of time. The effects of immersion time on degree of cross-linking, physicochemical properties and gas transport properties of the membrane have been studied. The cross-linked Matrimid membranes were

F. Aziz; A. F. Ismail

2010-01-01

429

Small para-hydrogen clusters doped with carbon monoxide: Quantum Monte Carlo simulations and observed infrared spectra  

NASA Astrophysics Data System (ADS)

The structures and rotational dynamics of clusters of a single carbon monoxide molecule solvated in para-hydrogen, (paraH2)N-CO, have been simulated for sizes up to N=17 using the reptation Monte Carlo technique. The calculations indicate the presence of two series of R(0) rotational transitions with J=1<--0 for cold clusters, similar to those predicted and observed in the case of HeN-CO. Infrared spectra of these clusters have been observed in the region of the C-O stretch (~2143 cm-1) in a pulsed supersonic jet expansion using a tunable diode laser probe. With the help of the calculations, the observed R(0) rotational transitions have been assigned up to N=9 for the b-type series and N=14 for the a-type series. Theory and experiment agree rather well, except that theory tends to overestimate the b-type energies. The (paraH2)12-CO cluster is calculated to be particularly stable and (relatively) rigid, corresponding to completion of the first solvation shell, and it is observed to have the strongest a-type transition.

Moroni, S.; Botti, M.; de Palo, S.; McKellar, A. R. W.

2005-03-01

430

Paired ion reversed-phase HPLC assay for the determination of iothalamic acid and para aminohippuric acid in urine.  

PubMed

A paired ion reversed-phase high performance liquid chromatographic method for simultaneous determination of iothalamic acid (Io) and para aminohippuric acid (PAH) in urine is described. The method uses a single internal standard for both drugs. The only sample preparation required is dilution of urine (1:100 or 1:500) with deionized water. The internal standard is added to a small aliquot of the diluted specimen and injected. For HPLC, a C8 column and a mobile phase consisting of potassium phosphate buffer with dodecyl triethylammonium phosphate IP reagent, 25% organic modifier with UV detection at 254 nm was used. Within day and between day variation for the assay were in the range of 1.48-9.46% for iothalamic acid and 1.84-10.36% for para aminohippuric acid for four levels of concentration. Limits of quantitation were 50.0 micrograms ml-1 for iothalamic acid and 75.0 micrograms ml-1 for para aminohippuric acid. Mean recovery was 98.55% for Io and 97.79% for PAH. This isocratic HPLC assay is simple, rapid and relatively inexpensive. PMID:7841228

Seneviratne, A K; Jayewardene, A L; Gambertoglio, J G

1994-10-01

431

Multistep conversion of para-substituted phenols by phenol hydroxylase and 2,3-dihydroxybiphenyl 1,2-dioxygenase.  

PubMed

A multistep conversion system of para-substituted phenols by recombinant phenol hydroxylase (PH(IND)) and 2,3-dihydroxybiphenyl 1,2-dioxygenase (BphC(LA-4)) was constructed in this study. Docking studies with different para-substituted phenols and corresponding catechols inside of the active site of PH(IND) and BphC(LA-4) predicted that all the substrates should be transformed. High-performance liquid chromatography-mass spectrometry analysis showed that the products of multistep conversion were the corresponding para-substituted catechols and semialdehydes. For the first-step conversion, the formation rate of 4-fluorocatechol (0.39 ?M/min/mg dry weight) by strain PH(IND) hydroxylation was 1.15, 6.50, 3.00, and 1.18-fold higher than the formation of 4-chlorocatechol, 4-bromocatechol, 4-nitrocatechol, and 4-methylcatechol, respectively. For the second-step conversion, the formation rates of semialdehydes by strain BphC(LA-4) were as follows: 5-fluoro-HODA>5-chloro-HODA>2-hydroxy-5-nitro-ODA>5-bromo-HODA>2-hydroxy-5-methyl-ODA. The present study suggested that the multistep conversion by both ring hydroxylase and cleavage dioxygenase should be potential in the synthesis of industrial precursors and provide a novel avenue in the wastewater recycling treatment. PMID:23371781

Qu, Yuanyuan; Shi, Shengnan; Ma, Qiao; Kong, Chunlei; Zhou, Hao; Zhang, Xuwang; Zhou, Jiti

2013-01-31

432

Microporosity linked fluid focusing and monazite instability in greenschist facies para-conglomerates, western India  

NASA Astrophysics Data System (ADS)

In a deformed para-conglomerate (western India), monazites occur as discrete grains (50–250 ?m long axis) in tonalite clasts, in the warping chlorite–biotite–calcite schist layers, and as disseminated grains (<5 ?m) along with xenotime and huttonite forming veins in schist layers. The veins are absent in clasts. Chlorite and biotite defining schistosity in schist layers and in synchronously-formed extensional veins/fractures in clasts are chemically identical. ?18O (VSMOW) and ?13C (VPDB) in calcite in schistosity, in clasts, and in "beards" in pressure shadow zones around clasts are tightly bracketed, 11.4–12.2‰ and –3.1 to –3.6‰ respectively.Margins of clast-hosted monazites are partly altered to fluorapatite – huttonite ± allanite ± Y-xenotime. By contrast, monazite alteration in schist layers is extensive. In schist layers, rafts of embayed monazite occur in fluorapatite-dominated corona studded with idiomorphic huttonite, Y-xenotime ± allanite. Mass balance calculation in a well-defined alteration zone around monazite in schist layer with P conserved indicate large gain in mass fraction of lower-abundance, less soluble HREEs, Y and Th in the alteration zone was compensated by minor loss in mass fraction of higher abundance elements (LREEs, MREEs) resulting in negligible net mass change. Monazite decomposition was associated with ˜50% dilation strain. Yb, Th and U abundances in alteration zones around decomposed monazites in schist layer are computed to be manifold higher than average schists.The contemporaneous formation of pore microstructures, the chemical homogeneity among ferromagnesian minerals and C–O isotope data in calcite in different textural domains, and results of mass balance calculations are compatible with deformation-aided porosity generation, synchronous fluid-mediated advection transport of elements, and dissolution–re-precipitation of mica–calcite aggregates at upper crustal conditions, ˜500 °C, ˜4 kbar. Monazite instability was induced by strain-focused influx of HREE, Y, Th and U rich fluids from external sources. The better preservation of within-clast monazite relative to the ones in weak-to-shear schist layers is attributed to limited fluid access through fewer porosity networks in actively deforming clasts.

Rekha, S.; Bhattacharya, A.; Viswanath, T. A.

2013-03-01

433

How Chlorine Atom Reacts with H2 in Ir-Irradiated Solid Para-Hydrogen  

NASA Astrophysics Data System (ADS)

The use of solid para-hydrogen ({p}-H2) as a matrix host has generated considerable interest in recent years. Solid {p}-H2 is considered as a quantum solid; hence it is "softer" than noble gas matrices and has several unique properties such as narrow bandwidths, feasibility of molecular and internal rotation, and a diminished cage effect, which is particularly relevant to the formation of atoms and radicals in a matrix using photolysis {in situ}. Raston and Anderson employed laser emission at 355 nm to photodissociate Cl2 trapped in solid {p}-H2 at 2 K and produced isolated Cl atoms. Excitation of the solid {p}-H2 with IR light in the range 4000-5000 cm-1 from a globar source induces reactions of Cl atoms with {p}-H2 to form HCl. We investigated the reaction of Cl with solid {p}-H2 with a tunable IR laser and a FTIR spectrometer. The Cl atoms were produced on irradiation of a Cl2/{p}-H2 (1/1000-1/4000) matrix with light at 365 nm from a light-emitting diode. By monitoring continuously the formation of HCl while tuning the wavelength of the IR laser, we obtained the relative yield of HCl as a function of excitation wavelength. We found that absorption of the Cl-H2 complex and solid H2, but not the Cl2-H2 complex, induced the reaction Cl + H2. In separate experiments we irradiated a selective area of the matrix with UV light and compared the yields of HCl in this area when we irradiated IR light at various locations. When the IR laser light irradiated outside the UV-irradiated area, excitation of {p}-H2 near 4229 cm-1, but not the Cl-H2 complex at 4148.5 cm-1, still produced HCl. In contrast, when the IR light irradiated inside the UV-irradiated region, more HCl was produced at 4148.5 cm-1. This indicates that the excited H2 can move around and react with Cl located far away from the originally excited area, whereas the IR excited Cl-H2 complex reacts directly to form HCl. We also found that irradiation of H2 produced some dimers of HCl, whereas irradiation at the Cl-H2 complex produced only HCl monomer. P. L. Raston and D. T. Anderson, J. Chem. Phys. 126, 021106 (2007). P. L. Raston and D. T. Anderson, Phys. Chem. Chem. Phys. 8, 3124 (2006).

Wu, Jen-Yu; Bahou, Mohammed; Lee, Yuan-Pern

2012-06-01

434

para-Aminobenzoic acid is a precursor in coenzyme Q6 biosynthesis in Saccharomyces cerevisiae.  

PubMed

Coenzyme Q (ubiquinone or Q) is a crucial mitochondrial lipid required for respiratory electron transport in eukaryotes. 4-Hydroxybenozoate (4HB) is an aromatic ring precursor that forms the benzoquinone ring of Q and is used extensively to examine Q biosynthesis. However, the direct precursor compounds and enzymatic steps for synthesis of 4HB in yeast are unknown. Here we show that para-aminobenzoic acid (pABA), a well known precursor of folate, also functions as a precursor for Q biosynthesis. A hexaprenylated form of pABA (prenyl-pABA) is normally present in wild-type yeast crude lipid extracts but is absent in yeast abz1 mutants starved for pABA. A stable (13)C(6)-isotope of pABA (p- amino[aromatic-(13)C(6)]benzoic acid ([(13)C(6)]pABA)), is prenylated in either wild-type or abz1 mutant yeast to form prenyl-[(13)C(6)]pABA. We demonstrate by HPLC and mass spectrometry that yeast incubated with either [(13)C(6)]pABA or [(13)C(6)]4HB generate both (13)C(6)-demethoxy-Q (DMQ), a late stage Q biosynthetic intermediate, as well as the final product (13)C(6)-coenzyme Q. Pulse-labeling analyses show that formation of prenyl-pABA occurs within minutes and precedes the synthesis of Q. Yeast utilizing pABA as a ring precursor produce another nitrogen containing intermediate, 4-imino-DMQ(6). This intermediate is produced in small quantities in wild-type yeast cultured in standard media and in abz1 mutants supplemented with pABA. We suggest a mechanism where Schiff base-mediated deimination forms DMQ(6) quinone, thereby eliminating the nitrogen contributed by pABA. This scheme results in the convergence of the 4HB and pABA pathways in eukaryotic Q biosynthesis and has implications regarding the action of pABA-based antifolates. PMID:20592037

Marbois, Beth; Xie, Letian X; Choi, Samuel; Hirano, Kathleen; Hyman, Kyle; Clarke, Catherine F

2010-06-30

435

Infrared Spectra of the 2-CHLOROPROPYL Radical in Solid Para-Hydrogen  

NASA Astrophysics Data System (ADS)

The reaction of chlorine atoms with propylene and one of its deuterium isotopomers in solid para-hydrogen (p-H2) matrices at 3.2 K has been studied using infrared spectroscopy. Irradiation at 365 nm of a co-deposited mixture of Cl2, C3H6, and p-H2 at 3.2 K produces a series of new lines in the infrared spectrum. Several of the new lines are readily assigned to the gauche and trans conformers of 1,2-dichloropropane (CH3CHClCH2Cl) resulting from the addition of two Cl atoms to C3H6. Weak lines observed at 802 and 975 cm-1 and at 813 and 981 cm-1 that become more prominent upon secondary irradiation at 254 and 214 nm are assigned to the allyl radical (C3H5) and an HCl-allyl radical complex (HCl-C3H5), respectively. Of the remaining lines, a strong line at 650 cm-1 and weaker lines at 532, 1008, 1133, 1150, 1215 and 1382 cm-1 are concluded to be due to a single carrier based on their behavior upon subsequent annealing to 4.5 K and irradiation at 254 and 214 nm. When the positions and intensities of these lines are compared to the MP2/aug-cc-pVDZ predicted vibrational spectra of the possible species that could result from the addition and abstraction reactions of one Cl atom with C3H6a, the best agreement is found with the 2-chloropropyl radical (CH3CHClCH2...). Isotopic experiments were performed with 3,3,3-C3H3D3 and the corresponding infrared peaks due to the deuterium isotopomer of this radical (CD3CHClCH2...) have also been observed. A final set of experiments were performed following irradiation of the Cl2/C3H6/p-H2 mixture at 365 nm, in which the matrix was irradiated with filtered infrared light from a globar source, which has been shown to induce a reaction between isolated Cl atoms and matrix H2 to produce HCl and H atoms. In our experiments, the major products observed after infrared irradiation are HCl, 2-chloropropane (CH3CHClCH3) and the isopropyl radical (CH3CH...CH3) and the possible mechanisms of formation of these species will be discussed. P. Brana and J. A. Sordo, J. Comput. Chem. 24, 2044 (2003) P. L. Raston and D. T. Anderson, Phys. Chem. Chem. Phys. 8, 3124 (2006)

Amicangelo, Jay C.; Golec, Barbara; Lee, Yuan-Pern

2012-06-01

436

Comparison of single-port laparoscopy and conventional laparoscopy for extraperitoneal para-aortic lymphadenectomy.  

PubMed

BACKGROUND: Extraperitoneal para-aortic lymphadenectomy (PAL) is used to treat gynecological cancers. This laparoscopic approach was first described using a multiport technique, and more recently, a single-port technique was developed. Our aim was to experimentally compare both approaches-conventional laparoscopy (CL) and single-port laparoscopy (SPL)-via the extraperitoneal laparoscopic approach. METHODS: From November 2006 to July 2012, extraperitoneal PAL was performed by CL or SPL using the GelPOINT device (Applied Medical). The surgical outcomes of the 2 groups were statistically analyzed. RESULTS: The study involved 69 patients; 36 underwent PAL with CL, and 33 patients underwent PAL with SPL. The mean operative times were 211.2 (range, 132-390) min and 159.6 (range, 120-255) min for the CL and SPL groups, respectively. The mean blood loss was not significantly different between the CL (52.5 mL; range, 0-100 mL) and SPL (40.5 mL; range, 0-100 mL, p = 0.62) groups. The average lymph node count was lower in the CL group (11.1; range, 4-29) compared to the SPL group (15; range, 3-19) (p = 0.03). However, this difference was not confirmed in the multivariate analysis (p = 0.16). The mean hospital stay was lower for the SPL group (2.2 days; range, 1-8 days) than the CL group (3.1 days; range, 1-5 days). In this case, the significant difference found in the univariate analysis (p = 0.02) was confirmed by the multivariate analysis (p = 0.0003). There were no conversions to open technique and no major complications. CONCLUSIONS: The SPL method appears to be a feasible approach, with surgical outcomes that are not statistically different from the CL method. The cosmetic aspect, the role of SPL in decreasing postoperative pain, and its impact on hospital stay must be confirmed prospectively in larger series. PMID:23783555

Hudry, Delphine; Cannone, Francesco; Houvenaeghel, Gilles; Buttarelli, Max; Jauffret, Camille; Chéreau, Elisabeth; Lambaudie, Eric

2013-06-20

437

Testicular shield for para-aortic radiotherapy and estimation of gonad doses  

PubMed Central

For radiotherapy of para-aortic and abdominal regions in male patients, gonads are to be protected to receive less than 2% of the prescribed dose. A testicular shield was fabricated for abdominal radiotherapy with 15 MV X-rays ((Clinac 2300 CD, Varian AG) with low melting point alloy (Cerroband). The dimensions of the testicular shield were 6.5 cm diameter and 3.5 cm depth with 1.5 cm wall thickness. During treatment, this shield was held in position by a rectangular sponge and Styrofoam support. Phantom measurement was carried out with a humanoid phantom and a 0.6 cc ion chamber. The mean energy of the scattered photon was calculated for single scattering at selected distances from the beam edge and with different field dimensions. One patient received radiotherapy with an inverted Y field and gonad doses were estimated using calibrated thermo-luminescent detector (TLD) chips. Measured doses with the ion chamber were 7.1 and 3.5% of the mid-plane doses without a shield at 3 and 7.5 cm off-field respectively. These values decreased to 4.6 and 1.7% with the bottom shield alone, and to 1.7 and 0.8% with both bottom and top shields covering the ion chamber. The measured doses at the gonads during the patient’s treatment were 0.5–0.92% for the AP field (0.74 ± 0.17%, n = 5) and 0.5–1.2% for the PA field (0.88 ± 0.24%, n = 5). The dose received by the testis for the full course of treatment was 32 cGy (0.8%) for a total mid-plane dose of 40 Gy. The first-scatter energy estimated at the gonads is around 1.14 MeV for a primary beam of 15 MV for a long axis dimension of 37 cm of primary field. During the patient’s treatment, the estimated absorbed doses at the gonads were comparable with reported values in similar treatments. The testicular shield reported in this study is of light weight and could be used conveniently in treatments of abdominal fields.

Ravichandran, R.; Binukumar, J. P.; Kannadhasan, S.; Shariff, M. H.; Ghamrawy, Kamal El

2008-01-01

438

Deposition, clearance, and shortening of Kevlar para-aramid fibrils in acute, subchronic, and chronic inhalation studies in rats.  

PubMed

The deposition and clearance of lung-deposited Kevlar para-aramid fibrils (subfibers) have been investigated as part of a subchronic and chronic inhalation toxicity testing program. Fibrils recovered from lung tissue in para-aramid-exposed Sprague-Dawley rats were microscopically counted and measured after exposures to airborne fibrils which were about 12 microns median length (ML) and < 0.3 micron median diameter. In each of three studies lung-recovered fibrils were progressively shorter with increasing residence time in the lungs. Twenty-eight days after a single 6-hr exposure at 400 respirable fibrils per cubic centimeter (f/cm3) the ML of recovered fibrils decreased to about 5 microns. Twenty-four months after a 3-week exposure to 25 or 400 f/cm3, fibrils reached about 2 microns ML. After 2 years of continuous exposure at 2.5, 25, or 100 f/cm3 or 1 year exposure plus 1 year recovery at 400 f/cm3, fibril ML approached 4 microns. In the 2-year study, the lung-fiber accumulation rate/exposure concentration was similar for the three highest concentrations and was about 3 x greater than that seen at 2.5 f/cm3, indicating that concentrations of about 25 f/cm3 or more may overwhelm clearance mechanisms. Time required for fibrils to be reduced to < 5 microns in the lung was markedly less at lower exposure concentration and shorter exposure time. The primary shortening mechanism is proposed to be long fibril cutting by enzymatic attack at fibril defects. However, length-selective fibril deposition and clearance may contribute to shortening in the first few days after exposure. The enzymatic cutting hypothesis is supported by measured increases in numbers of short fibers following cessation of exposures, continued shortening of the fibril length distribution up to 2 years following exposure, and in vitro fibril shortening after 3 months in a proteolytic enzyme preparation. The conclusion is that para-aramid fibrils are less durable in the lungs of rats than expected from the known chemical resistance of commercial yarn. These data suggest that at the low para-aramid fibril exposures found in the workplace, this fibril-shortening mechanism may limit the residence time of long fibers in the lungs of exposed workers. In addition, associated cascade impactor aerodynamic measurements indicate that due to their ribbon shape and curly nature, para-aramid fibrils behave aerodynamically larger than straight fibers. PMID:8258388

Kelly, D P; Merriman, E A; Kennedy, G L; Lee, K P

1993-10-01

440

Astatine211 labeling of an anti-melanoma antibody and its Fab fragment using N-succinimidyl para[²¹¹ At]astatobenzoate : comparisons In Vivo with the para-[¹²1]iodobenzoyl conjugate  

Microsoft Academic Search

Astatine-211 labeling of an anti-melanoma antibody, NR-ML-05, and its Fab fragment using N-succinimidyl para[²¹¹ At]astatobenzoate has been described. Preparation of the astatinated intermediate 2a was accomplished by distilling astatine-211 from an irradiated bismuth target directly into a reaction mixture containing an organometallic compound, N-succinimidyl p-(tri-n-butylstannyl)benzoate (1), and an oxidant, N-chlorosuccinimide, in 5% HOAc\\/MeOH. Trapping of distilled astatine as 2a was

S. W. Hadley; D. S. Wilbur; M. A. Gray; R. W. Atcher; NeoRx Corp

1991-01-01

441

Possible Derivations of Ortho- and Para-H2 Ratios in the Atmospheres of the Giant Planets Using the 2 ? m Spectral Structures of (H2)2  

NASA Astrophysics Data System (ADS)

We have presented an ab \\ initio model of the 2 ? m spectral features of (H2)2 based on the far-infrared models of McKellar & Schaefer (1991). We have shown that the intensity variations of the 2 ? m (H2)2 features depend on the ortho/para ratios of H2. We have discussed the applicability of the variations to the atmospheres of the giant planets for the derivations of the ortho/para ratios. The signal to noise ratios of currently available spectra of the giant planets are not sufficient enough to derive accurate ortho/para ratios of these planets. Observations with longer exposure times and larger telescope apertures are required to obtain better spectra for the derivations of the ortho/para ratios of H2 in the atmospheres of the giant planets.

Kim, Sang-Joon; Lee, Yong-Sik

2001-11-01

442

Energy Savers: Tips for Saving Energy and Money at Home; El Ahorro de Energa: Sugerencias para ahorrar energa y dinero en el hogar  

SciTech Connect

The Department of Energy of the United States of America works to guarantee provisions of safe energy, reliable and economically accessible to support to one developing economy and to protect the atmosphere. These suggestions and ideas to increase the energy efficiency in their house represent simple ways in which our citizens can contribute to preserve the atmosphere at world-wide level, to reduce the level of contamination of the air and to reserve our natural resources for future generations. [Spanish] El Departamento de Energa de los Estados Unidos de America trabaja para garantizar suministros de energa seguros, confiables y econmicamente accesibles para apoyar a una economa en desarrollo y proteger el medio ambiente. Estas sugerencias e ideas para aumentar la eficiencia energetica en su casa representan maneras sencillas en que nuestros ciudadanos pueden contribuir a preservar el medio ambiente a nivel mundial, a reducir el nivel de contaminacin del aire y a reservar nuestros recursos naturales para las generaciones futuras.

Jones, J.

2000-06-01

443

Candidates for Curative Resection in Advanced Gastric Cancer Patients Who Had Equivocal Para-aortic Lymph Node Metastasis on Computed Tomographic Scan  

Microsoft Academic Search

Background  The aim of this study was to determine how to select potential candidates for curative resection among advanced gastric patients with equivocal findings of para-aortic lymph node metastasis on computed tomography (CT).Methods  We analyzed the clinicopathologic results of 23 advanced gastric cancer patients who were diagnosed as having equivocal findings of para-aortic lymph node metastasis on a CT scan and who

Jun Ho Lee; Yong Hae Paik; Jong Seok Lee; Ho Joon Song; Keun Won Ryu; Chan Gyoo Kim; Sook Ryeon Park; Myoung Cheorl Kook; Young Woo Kim; Jae-Moon Bae

2006-01-01

444

A non-tree-based comprehensive study of metazoan Hox and ParaHox genes prompts new insights into their origin and evolution  

Microsoft Academic Search

BACKGROUND: Hox and the closely-related ParaHox genes, which emerged prior to the divergence between cnidarians and bilaterians, are the most well-known members of the ancient genetic toolkit that controls embryonic development across all metazoans. Fundamental questions relative to their origin and evolutionary relationships remain however unresolved. We investigate here the evolution of metazoan Hox and ParaHox genes using the HoxPred

Morgane Thomas-Chollier; Valérie Ledent; Luc Leyns; Michel Vervoort

2010-01-01

445

Characterization of a Conserved Interaction between DNA Glycosylase and ParA in Mycobacterium smegmatis and M. tuberculosis  

PubMed Central

The chromosome partitioning proteins, ParAB, ensure accurate segregation of genetic materials into daughter cells and most bacterial species contain their homologs. However, little is known about the regulation of ParAB proteins. In this study, we found that 3-methyladenine DNA glycosylase I MsTAG(Ms5082) regulates bacterial growth and cell morphology by directly interacting with MsParA (Ms6939) and inhibiting its ATPase activity in Mycobacterium smegmatis. Using bacterial two-hybrid and pull-down techniques in combination with co-immunoprecipitation assays, we show that MsTAG physically interacts with MsParA both in vitro and in vivo. Expression of MsTAG under conditions of DNA damage induction exhibited similar inhibition of growth as the deletion of the parA gene in M. smegmatis. Further, the effect of MsTAG on mycobacterial growth was found to be independent of its DNA glycosylase activity, and to result instead from direct inhibition of the ATPase activity of MsParA. Co-expression of these two proteins could counteract the growth defect phenotypes observed in strains overexpressing MsTAG alone in response to DNA damage induction. Based on protein co-expression and fluorescent co-localization assays, MsParA and MsTAG were further found to co-localize in mycobacterial cells. In addition, the interaction between the DNA glycosylase and ParA, and the regulation of ParA by the glycosylase were conserved in M. tuberculosis and M. smegmatis. Our findings provide important new insights into the regulatory mechanism of cell growth and division in mycobacteria.

Huang, Feng; He, Zheng-Guo

2012-01-01

446

Collisional excitation of CN(X2?+) by para- and ortho-H2: Fine-structure resolved transitions.  

PubMed

We present a new four dimensional potential energy surface (PES) for the CN(X(2)?(+))-H2 system. Both molecules were treated as rigid rotors. Potential energy was obtained from the electronic structure calculations using a partially spin-restricted coupled cluster with single, double, and perturbative triple excitations method. The four atoms were described using the augmented correlation-consistent triple zeta (aug-cc-pVTZ) basis sets augmented with mid-bond functions for improved description of van der Waals interactions. The global minimum is characterized by the well depth of 121.36 cm(-1) for the linear CN???H2 structure. The zero-order corrected dissociation energies D0 are 27.73 cm(-1) and 38.75 cm(-1) for the complex with para- and ortho-H2, respectively. These theoretical results obtained using our new PES are in excellent agreement with experimental values [Y. Chen and M. C. Heaven, J. Chem. Phys. 109, 5171 (1998)]. We perform fully quantum close coupling calculations of the rotationally inelastic cross sections of CN in collisions with para-H2 and ortho-H2 at low and intermediate energies. Corresponding rate coefficients were compared with experimental results of Brunet et al. [J. Chem. Phys. 116, 3617 (2002)]. A good agreement between theoretical and experimental results was found. Fine-structure resolved cross sections were then obtained through a recoupling technique. Significant differences exist between para- and ortho-H2 results. The propensity rules between fine-structure levels are also studied, and it is shown that the cross sections for ?j = ?N transitions are much larger than those for ?j ? ?N transitions, as expected from theoretical considerations. PMID:23968086

Kalugina, Yulia; K?os, Jacek; Lique, François

2013-08-21

447

Developing Continuous-Wave Raman Lasers Using Solid Para-Hydrogen and Barium Nitrate for Molecular Spectroscopy Applications  

NASA Astrophysics Data System (ADS)

Many interesting molecular targets have vibrational transitions between 5 and 10 ?m. However, widely tunable continuous-wave laser sources in this region are extremely rare. One possible solution to this situation is with continuous-wave Raman lasers. We will present our recent work toward the construction of two continuous-wave Raman lasers: one using solid para-hydrogen as the Raman shifting medium, and the other using barium nitrate. Solid para-hydrogen is a promising medium for a continuous-wave Raman laser because of its high Raman gain coefficient (18 cm/MW, almost 400 times higher than any room-temperature crystal), wide spectral transmission window (transparent from ˜100 nm to ˜30 ?m), its nature as a ``quantum crystal," and its large Raman shift (4150 cm-1 in the solid). We will also describe our more recent work designing and constructing a continuous-wave Raman laser in barium nitrate. Barium nitrate has the advantage of being the room-temperature crystal with the highest Raman gain coefficient, as well as being highly transparent from 350 to 1800 nm. Barium nitrate has been used as a continuous-wave Raman shifter for several years. Our recent work builds upon this foundation, combining lessons learned from our work with solid para-hydrogen. Our design is the first barium nitrate Raman laser using an actively-locked, doubly-resonant laser cavity. This holds the promise of requiring much lower threshold pump powers than previous setups. We will discuss some of the details in designing and building these lasers. Finally, we will report on the current state of our projects as well as anticipated future work.

Evans, William R.; Momose, Takamasa; McCall, Benjamin J.

2012-06-01

448

Collisional excitation of CN(X2?+) by para- and ortho-H2: Fine-structure resolved transitions  

NASA Astrophysics Data System (ADS)

We present a new four dimensional potential energy surface (PES) for the CN(X2?+)-H2 system. Both molecules were treated as rigid rotors. Potential energy was obtained from the electronic structure calculations using a partially spin-restricted coupled cluster with single, double, and perturbative triple excitations method. The four atoms were described using the augmented correlation-consistent triple zeta (aug-cc-pVTZ) basis sets augmented with mid-bond functions for improved description of van der Waals interactions. The global minimum is characterized by the well depth of 121.36 cm-1 for the linear CN...H2 structure. The zero-order corrected dissociation energies D0 are 27.73 cm-1 and 38.75 cm-1 for the complex with para- and ortho-H2, respectively. These theoretical results obtained using our new PES are in excellent agreement with experimental values [Y. Chen and M. C. Heaven, J. Chem. Phys. 109, 5171 (1998)]. We perform fully quantum close coupling calculations of the rotationally inelastic cross sections of CN in collisions with para-H2 and ortho-H2 at low and intermediate energies. Corresponding rate coefficients were compared with experimental results of Brunet et al. [J. Chem. Phys. 116, 3617 (2002)]. A good agreement between theoretical and experimental results was found. Fine-structure resolved cross sections were then obtained through a recoupling technique. Significant differences exist between para- and ortho-H2 results. The propensity rules between fine-structure levels are also studied, and it is shown that the cross sections for ?j = ?N transitions are much larger than those for ?j ? ?N transitions, as expected from theoretical considerations.

Kalugina, Yulia; K?os, Jacek; Lique, François

2013-08-01

449

Synthesis and optical properties of oligo- and poly(2,5-dialkoxy-1,4- para-phenylenevinylene)s  

Microsoft Academic Search

Model compounds based on 1,4-distyrylbenzene and its 2,5-dialkoxy derivatives were synthesized by the Wittig and Wittig-Horner methods. Corresponding poly(2,5-dialkoxy-1,4-para-phenylenevinylene)s (DAPPVs) were obtained from their 2,5-bis (chloromethyl)benzene monomers. The photophysical behavior of the model compounds and DAPPVs was investigated through absorbance, excitation and fluorescence spectroscopy. The absorbance and fluorescence spectra of DAPPVs are red shifted in comparison to the corresponding three-

N. N. Barashkov; D. J. Guerrero; H. J. Olivos; J. P. Ferraris

1995-01-01

450

A comparative study of the clearance of respirable para-aramid, chrysotile and glass fibres from rat lungs.  

PubMed

A number of studies have indicated that the relative toxicity of different fibre types after inhalation is related to their durability within lung tissue. The aim of this study was to assess the relative biopersistence of respirable para-aramid fibrils, chrysotile asbestos and code 100/475 glass fibres in rat lungs. The biopersistence of all three test fibres was measured by quantifying the changes in retained lung burden through time following 10 days inhalation exposure to the same target concentration (700 fibres ml-1) for each fibre type. The lung burden analyses for all three fibre types show large reductions in number and volume of retained fibres during the 16 months following exposure. Most of this reduction in lung fibre burden occurred during the first 3 months following exposure but the pattern of clearance of different size classes varies with fibre type. The para-aramid data show rapid clearance of the longest fibrils during the first months following exposure, combined with an initial increase in the numbers of shorter fibrils. This is consistent with the disintegration of para-aramid fibrils into shorter fragments that subsequently are more readily cleared by macrophages. The code 100/475 glass fibre data also show rapid clearance of the longer fibres combined with an increase in the numbers of very short fibres, consistent with the removal of long fibres through disintegration. In contrast, the chrysotile data show a more rapid reduction in the numbers of retained short fibres than of long fibres, which is consistent with preferential clearance of short fibres by macrophages and minimal transverse breakage of fibres. The biopersistence of all three fibre types, in terms of overall percentage of fibres retained after 16 months is similar, but the durability of long (> 15 microns) chrysotile fibres is very much greater than that of long fibres of code 100/475 glass or para-aramid. The clearance of the three fibre types cannot be adequately described by the first order kinetic model that is often applied in studies of lung clearance. The apparent half time of clearance of each of the fibre types depends on the size fraction and time interval examined. PMID:9155241

Searl, A

1997-04-01

451

Upper limit for the D2H+ ortho-to-para ratio in the prestellar core 16293E (CHESS)  

NASA Astrophysics Data System (ADS)

The H_3^+ ion plays a key role in the chemistry of dense interstellar gas clouds where stars and planets are forming. The low temperatures and high extinctions of such clouds make direct observations of H_3^+ impossible, but lead to large abundances of H2D+ and D2H+, which are very useful probes of the early stages of star and planet formation. The ground-state rotational ortho-D2H+ 11,1-00,0 transition at 1476.6 GHz in the prestellar core 16293E has been searched for with the Herschel HIFI instrument, within the CHESS (Chemical HErschel Surveys of Star forming regions) Key Program. The line has not been detected at the 21 mK km s-1 level (3? integrated line intensity). We used the ortho-H2D+ 11,0-11,1 transition and para-D2H+ 11,0-10,1 transition detected in this source to determine an upper limit on the ortho-to-para D2H+ ratio as well as the para-D2H+/ortho-H2D+