Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Environ Sci Technol ; 58(5): 2271-2281, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38270974

RESUMO

To mitigate methane emission from urban natural gas distribution systems, it is crucial to understand local leak rates and occurrence rates. To explore urban methane emissions in cities outside the U.S., where significant emissions were found previously, mobile measurements were performed in 12 cities across eight countries. The surveyed cities range from medium size, like Groningen, NL, to large size, like Toronto, CA, and London, UK. Furthermore, this survey spanned across European regions from Barcelona, ES, to Bucharest, RO. The joint analysis of all data allows us to focus on general emission behavior for cities with different infrastructure and environmental conditions. We find that all cities have a spectrum of small, medium, and large methane sources in their domain. The emission rates found follow a heavy-tailed distribution, and the top 10% of emitters account for 60-80% of total emissions, which implies that strategic repair planning could help reduce emissions quickly. Furthermore, we compare our findings with inventory estimates for urban natural gas-related methane emissions from this sector in Europe. While cities with larger reported emissions were found to generally also have larger observed emissions, we find clear discrepancies between observation-based and inventory-based emission estimates for our 12 cities.


Assuntos
Poluentes Atmosféricos , Gás Natural , Cidades , Gás Natural/análise , Metano/análise , Poluentes Atmosféricos/análise , Londres
2.
BJS Open ; 4(3): 456-466, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32277807

RESUMO

BACKGROUND: Although total tumour volume (TTV) may have prognostic value for hepatic resection in certain solid cancers, its importance in colorectal liver metastases (CRLM) remains unexplored. This study investigated its prognostic value in patients with resectable CRLM. METHOD: This was a retrospective review of patients who underwent hepatic resection for CRLM between 2008 and 2017 in a single institution. TTV was measured from CT images using three-dimensional construction software; cut-off values were determined using receiver operating characteristic (ROC) curve analyses. Potential prognostic factors, overall survival (OS) and recurrence-free survival (RFS) were determined using multivariable and Kaplan-Meier analyses. RESULTS: Some 94 patients were included. TTV cut-off values for OS and RFS were 100 and 10 ml respectively. Right colonic primary tumours, primary lymph node metastasis and bilobar liver metastasis were included in the multivariable analysis of OS; a TTV of 100 ml or above was independently associated with poorer OS (hazard ratio (HR) 6·34, 95 per cent c.i. 2·08 to 17·90; P = 0·002). Right colonic primary tumours and primary lymph node metastasis were included in the RFS analysis; a TTV of 10 ml or more independently predicted poorer RFS (HR 1·90, 1·12 to 3·57; P = 0·017). The 5-year OS rate for a TTV of 100 ml or more was 41 per cent, compared with 67 per cent for a TTV below 100 ml (P = 0·006). Corresponding RFS rates with TTV of 10 ml or more, or less than 10 ml, were 14 and 58 per cent respectively (P = 0·009). A TTV of at least 100 ml conferred a higher rate of unresectable initial recurrences (12 of 15, 80 per cent) after initial hepatic resection. CONCLUSION: TTV was associated with RFS and OS after initial hepatic resection for CRLM; TTV of 100 ml or above was associated with a higher rate of unresectable recurrence.


ANTECEDENTES: Aunque el volumen total del tumor (total tumour volume, TTV) puede tener valor pronóstico tras la resección hepática (hepatic resection, HR) en algunas neoplasias sólidas, no se conoce su importancia en las metástasis hepáticas de cáncer colorrectal (colorectal liver metastases, CRLMs). Este estudio analizó el valor pronóstico del TTV en pacientes con CRLMs resecables. MÉTODOS: Revisión retrospectiva de pacientes a los que se realizó una HR por CRLMs entre 2008 y 2017 en un solo centro. El TTV se estimó a partir de imágenes de tomografía computarizada utilizando un programa de reconstrucción 3D; se determinaron los valores de corte mediante un análisis de las características operativas del receptor. Se identificaron los posibles factores pronósticos y se calcularon la supervivencia global (overall survival, OS) y la supervivencia libre de recidiva (recurence-free survival, RFS) mediante análisis multivariados y de Kaplan-Meier. RESULTADOS: Se incluyeron 94 pacientes. Los valores de corte del TTV para la OS y la RFS fueron de 100 mL y 10 mL, respectivamente. En el análisis multivariable para la OS, se incluyeron los tumores del colon derecho, las metástasis linfáticas primarias y la metástasis hepática bilobar; un TTV ≥ 100 mL se asoció de forma independiente con una peor OS (cociente de riesgos instantáneos, hazard ratio, HR, 6,34, i.c. del 95% 2,08-17,9; P = 0,002). En el anáisis para la RFS, se incluyeron tumores primarios de colon derecho y las metástasis linfáticas primarias; un TTV ≥ 10 mL predijo de forma independiente una peor RFS (HR 1,90, i.c. del 95% 1,12-3,57; P = 0,017). Las tasas de OS a los 5 años con TTVs ≥ 100 mL versus < 100 mL fueron del 41% versus 67% (P = 0,006); las tasas de RFS respecto a TTVs ≥ 10 mL versus < 10 mL fueron del 14% versus 58% (P = 0,009). Un TTV ≥ 100 mL conllevó una tasa más elevada (80%) de recidivas no resecables después de la HR inicial. CONCLUSIÓN: El TTV se asoció con la RFS y la OS tras la HR por CRLMs; unos valores ≥ 100 mL conllevan una tasa más elevada de recidiva irresecable.


Assuntos
Neoplasias Colorretais/patologia , Neoplasias Hepáticas/secundário , Carga Tumoral , Idoso , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/cirurgia , Feminino , Humanos , Japão , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/cirurgia , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/cirurgia , Prognóstico , Estudos Retrospectivos , Análise de Sobrevida , Fatores de Tempo
3.
Sci Rep ; 9(1): 20033, 2019 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-31882705

RESUMO

Nitrogen dioxide (NO2) is a regulated air pollutant that is of particular concern in many cities, where concentrations are high. Emissions of nitrogen oxides to the atmosphere lead to the formation of ozone and particulate matter, with adverse impacts on human health and ecosystems. The effects of emissions are often assessed through modeling based on inventories relying on indirect information that is often outdated or incomplete. Here we show that NO2 measurements from the new, high-resolution TROPOMI satellite sensor can directly determine the strength and distribution of emissions from Paris. From the observed build-up of NO2 pollution, we find highest emissions on cold weekdays in February 2018, and lowest emissions on warm weekend days in spring 2018. The new measurements provide information on the spatio-temporal distribution of emissions within a large city, and suggest that Paris emissions in 2018 are only 5-15% below inventory estimates for 2011-2012, reflecting the difficulty of meeting NOx emission reduction targets.

4.
Environ Pollut ; 159(10): 2935-46, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21561695

RESUMO

The vertical allocation of emissions has a major impact on results of Chemistry Transport Models. However, in Europe it is still common to use fixed vertical profiles based on rough estimates to determine the emission height of point sources. This publication introduces a set of new vertical profiles for the use in chemistry transport modeling that were created from hourly gridded emissions calculated by the SMOKE for Europe emission model. SMOKE uses plume rise calculations to determine effective emission heights. Out of more than 40,000 different vertical emission profiles 73 have been chosen by means of hierarchical cluster analysis. These profiles show large differences to those currently used in many emission models. Emissions from combustion processes are released in much lower altitudes while those from production processes are allocated to higher altitudes. The profiles have a high temporal and spatial variability which is not represented by currently used profiles.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Atmosfera/química , Movimentos do Ar , Altitude , Monitoramento Ambiental , Europa (Continente) , Modelos Químicos
5.
Water Sci Technol ; 56(1): 223-31, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17711019

RESUMO

In this article we show that brake wear from road traffic vehicles is an important source of atmospheric (particulate) copper concentrations in Europe. Consequently, brake wear also contributes significantly to deposition fluxes of copper to surface waters. We estimated the copper emission due to brake wear to be 2.4 kiloton per year. For comparison, the official database for Europe (without brake wear) totals 2.6 kiloton per year. In Western Europe the brake wear emissions dominate the total emission of copper. Using the spatially resolved emission data, copper distributions over Europe were calculated with the LOTOS-EUROS model. Without brake wear the model underestimates observed copper concentrations by a factor of 3, which is in accordance with other studies. Including the brake wear emissions largely removes the bias. We find that 75% of the atmospheric copper input in the North Sea may be due to brake wear. We estimate that about 25% of the total copper input in the Dutch part of the North Sea stems from brake wear. Although the estimated brake wear copper emission is associated with a large uncertainty, it significantly improves our understanding of the copper cycle in the environment.


Assuntos
Automóveis , Cobre/análise , Poluentes Ambientais/análise , Difusão , Europa (Continente) , Esgotos , Fatores de Tempo
6.
Proc Natl Acad Sci U S A ; 99(19): 12021-4, 2002 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-12189212

RESUMO

Microbial production in anoxic wetland rice soils is a major source of atmospheric CH4 the most important non-CO2 greenhouse gas. Much higher CH4 emissions from well managed irrigated rice fields in the wet than in the dry season could not be explained by seasonal differences in temperature. We hypothesized that high CH4 emissions in the wet season are caused by low grain to biomass ratios. In a screenhouse experiment, removing spikelets to reduce the plants' capacity to store photosynthetically fixed C in grains increased CH4 emissions, presumably via extra C inputs to the soil. Unfavorable conditions for spikelet formation in the wet season may similarly explain high methane emissions. The observed relationship between reduced grain filling and CH4 emission provides opportunities to mitigate CH4 emissions by optimizing rice productivity.


Assuntos
Metano/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Agricultura , Poluentes Atmosféricos/metabolismo , Atmosfera/análise , Carbono/metabolismo , Efeito Estufa , Modelos Biológicos , Nitrogênio/metabolismo , Oryza/microbiologia , Fotossíntese , Estações do Ano
7.
Jpn J Antibiot ; 34(8): 1196-201, 1981 Aug.
Artigo em Japonês | MEDLINE | ID: mdl-6172609

RESUMO

Ultrastructural alterations of rat ventral prostate were studied following the administration of peplomycin sulfate (NK631) to evaluate the efficacy of this drug to the human prostatic carcinoma. The rats as experimental animals were divided into 3 groups: control, castrated and NK631 administration ones with 5 mg per kg per day. Rat body weight and ventral prostatic weight were measured at 4, 7 and 14 days after the treatment. Simultaneously prostatic tissue samples were obtained for electron microscopic study. The ventral prostatic weight and body weight ratio (VBW) was utilized in respect to the prostatic weight to compared the experimental groups with control ones. The VBW was significantly decreased at 14 days after castration. NK631 administration showed only minor decrease at 14 days duration. However, statistics for control and NK631 were different. Ultrastructurally, normal rat ventral prostate demonstrated to contain abundant rough endoplasmic reticulum and well developed GOLGI apparatus and round nucleus. After castration, ventral prostatic cells lost their normal cytoplasmic configuration with the atrophy of rough endoplasmic reticulum and GOLGI apparatus, while secondary lysosomes were occasionally found in the cytoplasm. During the course of NK631 administration, the changes were detected in the cytoplasm with marked vacuolization and degeneration of rough endoplasmic reticulum as well as disappearances of cytoplasmic matrix. Nucleus was also affected with the marked indentation of nuclear membrane and disappearance of nucleoplasm. From the present preliminary investigation, NK631 could induce the cytostatic changes to rat ventral prostate. Therefore, NK631 would be suggested to contribute to the treatment of prostatic carcinoma. It is hoped that as more experimental studies are processed, a deeper understanding of the effect of NK631 would be clarified.


Assuntos
Bleomicina/farmacologia , Próstata/efeitos dos fármacos , Animais , Masculino , Tamanho do Órgão/efeitos dos fármacos , Peplomicina , Próstata/ultraestrutura , Ratos , Ratos Endogâmicos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA