ABSTRACT
Greenhouse gas (GHG) emissions associated with extraction of bitumen from oil sands can vary from project to project and over time. However, the nature and magnitude of this variability have yet to be incorporated into life cycle studies. We present a statistically enhanced life cycle based model (GHOST-SE) for assessing variability of GHG emissions associated with the extraction of bitumen using in situ techniques in Alberta, Canada. It employs publicly available, company-reported operating data, facilitating assessment of inter- and intraproject variability as well as the time evolution of GHG emissions from commercial in situ oil sands projects. We estimate the median GHG emissions associated with bitumen production via cyclic steam stimulation (CSS) to be 77 kg CO2eq/bbl bitumen (80% CI: 61-109 kg CO2eq/bbl), and via steam assisted gravity drainage (SAGD) to be 68 kg CO2eq/bbl bitumen (80% CI: 49-102 kg CO2eq/bbl). We also show that the median emissions intensity of Alberta's CSS and SAGD projects have been relatively stable from 2000 to 2013, despite greater than 6-fold growth in production. Variability between projects is the single largest source of variability (driven in part by reservoir characteristics) but intraproject variability (e.g., startups, interruptions), is also important and must be considered in order to inform research or policy priorities.
Subject(s)
Greenhouse Gases , Alberta , Greenhouse Effect , Oil and Gas Fields , SteamABSTRACT
BACKGROUND: We previously detected Helicobacter pylori infection by stool antigen ELISA assay in 33-41% of asymptomatic Chilean children between 2-3 years of age, of which 11-20% had a transient infection and 21-22% a persistent infection. A total of 88% of ELISA-positive samples were also rtPCR positive, while 37/133 (33%) of ELISA-negative stool samples were rtPCR positive. The significance of a ELISA-negative/rtPCR-positive sample requires clarification. We aimed to determine whether rtPCR is able to detect persistent infections not detected by ELISA. MATERIALS AND METHODS: We selected 36 children with an ELISA-negative/rtPCR-positive stool sample, of which 25 were never H. pylori infected according to ELISA, and 11 had a transient infection with an ELISA-positive sample before or after the discordant sample. At least two additional consecutive ELISA-negative samples per child were tested in duplicate by rtPCR for the 16s rRNA gene. RESULTS: A total of 14 of 78 (17.9%) rtPCR reactions were positive, but only 4/78 (5.1%) were positive in both duplicates, representing a total of 3/36 (8.3%) children with an additional rtPCR-positive sample, only one of whom was persistently negative by ELISA. One child with a transient infection had two positive rtPCR reactions despite negative ELISA samples. CONCLUSIONS: In H. pylori noninfected or transiently infected children, as determined by stool ELISA, additional ELISA-negative/rtPCR-positive stool samples were found in 8.3% of children, but a possible persistent infection was only identified in 2.7% of children. Thus, the characterization of infection dynamics in children is not being misrepresented by application of stool ELISA. Furthermore, rtPCR does not significantly improve dynamic characterization.
Subject(s)
Enzyme-Linked Immunosorbent Assay/methods , Feces/microbiology , Helicobacter Infections/diagnosis , Helicobacter pylori/isolation & purification , RNA, Bacterial/genetics , RNA, Ribosomal, 16S/genetics , Real-Time Polymerase Chain Reaction/methods , Child , Child, Preschool , Female , Helicobacter Infections/microbiology , Helicobacter pylori/genetics , Humans , Infant , Infant, Newborn , Male , Prospective StudiesABSTRACT
BACKGROUND: Helicobacter pylori, the main cause of peptic ulcer disease and gastric cancer in adult populations, is generally acquired during the first years of life. Infection can be persistent or transient and bacterial and host factors determining persistence are largely unknown and may prove relevant for future disease. METHODS: Two cohorts of healthy Chilean infants (313 total) were evaluated every 3 months for 18-57 months to determine pathogen- and host-factors associated with persistent and transient infection. RESULTS: One-third had at least one positive stool ELISA by age 3, with 20% overall persistence. Persistent infections were acquired at an earlier age, associated with more household members, decreased duration of breastfeeding, and nonsecretor status compared to transient infections. The cagA positive strains were more common in persistent stools, and nearly 60% of fully characterized persistent stool samples amplified cagA/vacAs1m1. Persistent children were more likely to elicit a serologic immune response, and both infection groups had differential gene expression profiles, including genes associated with cancer suppression when compared to healthy controls. CONCLUSIONS: These results indicate that persistent H. pylori infections acquired early in life are associated with specific host and/or strain profiles possibly associated with future disease occurrence.
Subject(s)
Feces/microbiology , Helicobacter Infections/epidemiology , Helicobacter pylori/isolation & purification , Antibodies, Bacterial/blood , Antigens, Bacterial/genetics , Asymptomatic Diseases , Bacterial Proteins/genetics , Child, Preschool , Chile/epidemiology , Cohort Studies , Enzyme-Linked Immunosorbent Assay , Gene Expression Profiling , Helicobacter Infections/immunology , Helicobacter Infections/microbiology , Helicobacter pylori/genetics , Helicobacter pylori/pathogenicity , Host-Pathogen Interactions , Humans , Infant , Polymerase Chain Reaction , Prospective Studies , Time FactorsABSTRACT
INTRODUCCIÓN: la especie Bursera graveolens Triana & Planch, comúnmente llamada palo santo, es una planta nativa de las costas ecuatorianas y peruanas. OBJETIVOS: contribuir al estudio fitoquímico y farmacológico de la especie B. graveolens, nativa de San José de Ancón, provincia de Santa Elena, Ecuador. MÉTODOS: se empleó el extracto hidroalcohólico 50 porciento de ramas secas. Se realizó un estudio fitoquímico a través del sistema acoplado de cromatografía gaseosa-espectrometría de masas y se determinó el efecto antiinflamatorio en el modelo de edema de la oreja inducido por aceite de Crotón en ratones albinos de la línea OF1. RESULTADOS: el tamizaje fitoquímico mostró presencia de aceites esenciales, triterpenos-esteroides, compuestos fenólicos, flavonoides, quinonas, antocianidinas, saponinas y compuestos reductores. Se determinó estructuras a 11 componentes del aceite esencial extraído de las ramas y el sesquiterpeno denominado viridiflorol resultó el componente mayoritario con 70,82 porciento, este compuesto se informa por primera vez en esta especie. El extracto hidroalcohólico (25 mL a cada lado de las orejas tratadas) inhibió significativamente la inflamación comparado con la bencidamina. CONCLUSIONES: los extractos hidroalcohólicos mostraron un efecto antiinflamatorio en las condiciones experimentales del estudio y se determinó la composición química del aceite de ramas de B. graveolens de Ecuador.
INTRODUCTION: Bursera graveolens Triana & Planch. species, commonly called palo santo, is an indigenous plant from Ecuadorian and Peruvian coasts. OBJECTIVES: to contribute to the phytochemical and pharmacological study of B. graveolens species from San José de Ancon, Santa Elena province, Ecuador. METHODS: 50 percent hydroalcoholic extract from dry branches was used. The phytochemical study was based on a combined system of gas chromatography-mass spectrometry and the antinflammatory effect was determined in the model of ear edema induced by Croton oil in albino OF1 mice. RESULTS: phytochemical screening showed the existence of essential oils, triterpen-steroids, phenolic compounds, flavonoids, quinones, antocyanidines, saponins and reducing compounds. The structures of eleven essential oil components from branches were determined whereas sesquiterpene called viridiflorol turned out to be the main component with 70,82 percent; this is the first time that this compound is reported in this species. The hydroalcoholic extract (25 mL applied at each side of the treated ears) significantly inhibited the inflammation compared with the effect of benzydamine. CONCLUSIONS: hydroalcoholic extracts showed antinflammatory effect under experimental study conditions and the chemical composition of branch oil from B. graveolens from Ecuador was determined.
Subject(s)
Bursera/chemistry , Gas Chromatography-Mass Spectrometry/methods , Edema/drug therapy , Plant Extracts/pharmacology , Plant Extracts/therapeutic use , Ear AuricleABSTRACT
INTRODUCCIÓN: la especie Bursera graveolens Triana & Planch, comúnmente llamada palo santo, es una planta nativa de las costas ecuatorianas y peruanas. OBJETIVOS: contribuir al estudio fitoquímico y farmacológico de la especie B. graveolens, nativa de San José de Ancón, provincia de Santa Elena, Ecuador. MÉTODOS: se empleó el extracto hidroalcohólico 50 porciento de ramas secas. Se realizó un estudio fitoquímico a través del sistema acoplado de cromatografía gaseosa-espectrometría de masas y se determinó el efecto antiinflamatorio en el modelo de edema de la oreja inducido por aceite de Crotón en ratones albinos de la línea OF1. RESULTADOS: el tamizaje fitoquímico mostró presencia de aceites esenciales, triterpenos-esteroides, compuestos fenólicos, flavonoides, quinonas, antocianidinas, saponinas y compuestos reductores. Se determinó estructuras a 11 componentes del aceite esencial extraído de las ramas y el sesquiterpeno denominado viridiflorol resultó el componente mayoritario con 70,82 porciento, este compuesto se informa por primera vez en esta especie. El extracto hidroalcohólico (25 mL a cada lado de las orejas tratadas) inhibió significativamente la inflamación comparado con la bencidamina. CONCLUSIONES: los extractos hidroalcohólicos mostraron un efecto antiinflamatorio en las condiciones experimentales del estudio y se determinó la composición química del aceite de ramas de B. graveolens de Ecuador(AU)
INTRODUCTION: Bursera graveolens Triana & Planch. species, commonly called palo santo, is an indigenous plant from Ecuadorian and Peruvian coasts. OBJECTIVES: to contribute to the phytochemical and pharmacological study of B. graveolens species from San José de Ancon, Santa Elena province, Ecuador. METHODS: 50 percent hydroalcoholic extract from dry branches was used. The phytochemical study was based on a combined system of gas chromatography-mass spectrometry and the antinflammatory effect was determined in the model of ear edema induced by Croton oil in albino OF1 mice. RESULTS: phytochemical screening showed the existence of essential oils, triterpen-steroids, phenolic compounds, flavonoids, quinones, antocyanidines, saponins and reducing compounds. The structures of eleven essential oil components from branches were determined whereas sesquiterpene called viridiflorol turned out to be the main component with 70,82 percent; this is the first time that this compound is reported in this species. The hydroalcoholic extract (25 mL applied at each side of the treated ears) significantly inhibited the inflammation compared with the effect of benzydamine. CONCLUSIONS: hydroalcoholic extracts showed antinflammatory effect under experimental study conditions and the chemical composition of branch oil from B. graveolens from Ecuador was determined(AU)
