Polycyclic aromatic hydrocarbons (PAHS) (I): Toxicity, population exposure and involved foods

Food is one of the main exogenous sources of genotoxic compounds. In heated food products, polycyclic aromatic hydrocarbons (PAHs) represent a priority group of genotoxic, mutagenic and/or carcinogenic chemical pollutants with adverse long-term health effects. People can be exposed to these compounds through different environments and via various routes: inhalation, ingestion of foods and water and even percutaneously. The presence of these compounds in food may be due to environmental contamination, to industrial handling and processing of foods and to oil processing and refining. The highest levels of these compounds are found in smoked foods, in seafood which is found in polluted waters, in grilled meats and, to a lesser extent, in vegetable fats and oils. Lower levels of PAHs are found in vegetables and in cereals and its products.

(Table DR1) Biogenic silica and chert in the Pacific Ocean, DSDP and ODP data

Evidence for the dissolution of biogenic silica at the base of pelagic sections supports the hypothesis that much of the chert formed in the Pacific derives from the dissolution and reprecipitation of this silica by hydrothermal waters. As ocean bottom waters flow into and through the crust, they become warmer. Initially they remain less saturated with respect to dissolved silica than pore water in the overlying sediments. With the diffusion of heat, dissolved ions, and to some extent the advection of water itself, biogenic silica in the basal part of the sedimentary section is dissolved. Upon conductively cooling, these pore waters precipitate chert layers. The most common thickness for the basal silica-free zone (20 m) lies below the most common height of the top of the chert interval above basement (50 m). This mode of chert formation explains the frequent occurrence of chert layers at very shallow subbottom depths in pelagic sections of the Pacific. It is also consistent with the common occurrence of cherts

Occurrence of hiatuses PH and NH 1 through NH 7 in DSDP holes

Miocene paleoceanographic evolution exhibits major changes resulting from the opening and closing of passages, the subsequent changes in oceanic circulation, and development of major Antarctic glaciation. The consequences and timing of these events can be observed in variations in the distribution of deep-sea hiatuses, sedimentation patterns, and biogeographic distribution of planktic organisms. The opening of the Drake Passage in the latest Oligocene to early Miocene (25-20 Ma) resulted in the establishment of the deep circumpolar current, which led to thermal isolation of Antarctica and increased global cooling. This development was associated with a major turnover in planktic organisms, resulting in the evolution of Neogene assemblages and the eventual extinction of Paleogene assemblages. The erosive patterns of two widespread hiatuses (PH, 23.0-22.5 Ma; and NH 1, 20-18 Ma) indicate that a deep circumequatorial circulation existed at this time, characterized by a broad band of carbonate-ooze deposition. Siliceous sedimentation was restricted to the North Atlantic and a narrow band around Antarctica. A major reorganization in deep-sea sedimentation and hiatus distribution patterns occurred near the early/middle Miocene boundary, apparently resulting from changes in oceanic circulation. Beginning at this time, deep-sea erosion occurred throughout the Caribbean (hiatus NH 2, 16-15 Ma), suggesting disruption of the deep circumequatorial circulation and northward deflection of deep currents, and/or intensification of the Gulf Stream. Sediment distribution patterns changed dramatically with the sudden appearance of siliceous-ooze deposition in the marginal and east equatorial North Pacific by 16.0 to 15.5 Ma, coincident with the decline of siliceous sedimentation in the North Atlantic. This silica switch may have been caused by the introduction of Norwegian Overflow Water into the North Atlantic acting as a barrier to outcropping of silica-rich Antarctic Bottom Water. The main aspects of the present oceanic circulation system and sediment distribution pattern were established by 13.5 to 12.5 Ma (hiatus NH 3), coincident with the establishment of a major East Antarctic ice cap. Antarctic glaciation resulted in a broadening belt of siliceous-ooze deposition around Antarctica, increased siliceous sedimentation in the marginal and east equatorial North Pacific and Indian Oceans, and further northward restriction of siliceous sediments in the North Atlantic. Periodic cool climatic events were accompanied by lower eustatic sea levels and widespread deep-sea erosion at 12 to 11 Ma (NH 4), 10 to 9 Ma (NH 5), 7.5 to 6.2 Ma (NH 6), and 5.2 to 4.7 Ma (NH 7).

Paleoelevations in the Pacific Ocean 35 million years ago

Data from deep sea drilling, linear magnetic anomalies and bathymetric measurements together with age and morphometric characteristics of seamounts have been used to construct a paleobathymetric map of the oceans 35 million years ago. A brief analysis of these results is presented.

Les filles de marbre : drame en cinq actes, mêlé de chant. [Suivi de] Le cousin du Roi : comédie en un acte, en vers. Livr. 317 / par MM. Théodore Barrière et Lambert Thiboust... ; par MM. Philoxène Boyer et Théodore de Banville

Collection : Théâtre contemporain illustré ; 316e et 317e livraisons

Radio 33 comparado con el patrón de oro para diagnóstico de osteoporosis

Introducción: la medición de la densidad mineral ósea en el fémur y columna lumbar es considerada la prueba de oro para el diagnóstico de osteoporosis en mujeres postmenopáusicas, sin tener suficiente evidencia de la utilidad al medir de manera individual o simultanea el radio 33 con este mismo propósito. Metodología Se realizó un estudio de pruebas diagnósticas, valorando concordancia anidada para determinar el valor diagnóstico del radio 33 comparado con los resultados por dual fémur y columna, actualmente patrón de oro el en diagnóstico. Se incluyeron mujeres mayores de 50 años entre el periodo de 2008 y 2011. Resultados Se incluyeron 3241 osteodensitometrias de pacientes femeninas con columna AP, dual fémur, radio ultradistal y radio 33. Tomando como estándar de oro la medición en columna y/o femur, el radio-33 obtuvo una sensibilidad de 95.5% y especificidad de 91% (p= 0,000) para osteoporosis, y una sensibilidad de 76.5% y especificidad de 54.9% p=0,000 para el diagnóstico de osteopenia. El radio 33 permite diagnosticar un 35% adicional de casos que no son captados con la medición en fémur y columna lumbar. Discusión La osteodensitometría en los sitios usados comúnmente, predice únicamente el 40% del riesgo de fractura (1). Si se incluye la medición de radio 33, la sensibilidad de la osteodensitometría sube en un 35.66% adicional, logrando detectar más pacientes con este riesgo y generando un impacto en la oportunidad del tratamiento y quizás reducción en la morbi-mortalidad secundaria a fracturas en esta población susceptible.