Force dependent fragility in RNA hairpins

We apply Kramers theory to investigate the dissociation of multiple bonds under mechanical force and interpret experimental results for the unfolding/refolding force distributions of an RNA hairpin pulled at different loading rates using laser tweezers. We identify two different kinetic regimes depending on the range of forces explored during the unfolding and refolding process. The present approach extends the range of validity of the two-states approximation by providing a theoretical framework to reconstruct free-energy landscapes and identify force-induced structural changes in molecular transition states using single molecule pulling experiments. The method should be applicable to RNA hairpins with multiple kinetic barriers.Comment: Latex file, 4 pages+3 figure

Viabilidad de dermatofitos en muestras clínicas almacenadas

Con la finalidad de determinar la viabilidad en el tiempo de las estructuras fúngicas de dermatofitos y levaduras en muestras clínicas alñmacenadas, se estudiaron 257 muestras (2 a 7 años de antiguedad) colectadas entre Enero de 1990 y Diciembre de 1994 (206 de uña, 43 de piel y 8 de pelo).El examen microscópico directo se realizó con KOH-tinta Parker y posterior cultivo en Agar Sabouraud-CAF y Agar Lactrimel-CAF por 10-15 días a 28ºC.Como controles se analizaron con la misma metodología, 33 muestras de 5-8 meses de almacenamiento.En el 100% de las muestras control, se observaron elementos fúngicos y solo en el 21% de las almacenadas durante 5-6 meses se logró aislar nuevamente el agente causal. La especie más detectada fue T. rubrum.El 70,4% de las muestras almacenadas por un período superior a los8 mese presentaron estructuras fúngicas al examen microscópico, sin embargo, todos sus cultivos resultaron negativos

Amblyraja georgiana, Antarctic Starry Skate

The Antarctic Starry Skate (Amblyraja georgiana) is a medium-sized (to 115 cm total length) deepwater skate that occurs in the Southeast Pacific Ocean off southern Chile, in the Southwest Atlantic Ocean off southern Argentina and the Falkland Islands (Malvinas), in the Atlantic and Pacific Antarctic Oceans from South Georgia Island and the Antarctic Peninsula to the Ross Sea, and in the Indian Antarctic off the Crozet Islands. It is demersal on continental and insular slopes at depths of 20?1,255 m, and is captured as bycatch in trawl and longline fisheries, particularly those targeting Patagonian Toothfish (Dissostichus eleginoides). There are no population size estimates for this skate, and it is not clear what the current population trend is. Although estimates of bycatch around South Georgia and the Ross Sea are comprised of a low percentage of overall estimated stock biomass, the demographic consequences are unknown and require further research. Furthermore, catch levels in other areas are unknown, and some specimens previously referred to as this species may include cryptic individuals of a yet-to-be-described species. Overall, it is not clear what level of fishing mortality this species is exposed to across its range, and further research is needed on distribution, population size and trend, and threats. Therefore, the Antarctic Starry Skate is assessed as Data Deficient.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Acuña, E.. Universidad Católica del Norte; ChileFil: Bustamante, C.. Universidad de Antofagasta; ChileFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J.M.. Wildlife Conservation Society; Estados UnidosFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Pompert, J.. No especifíca;Fil: Velez Zuazo, X.. No especifíca

Schroederichthys bivius, Narrowmouth Catshark

The Narrowmouth Catshark (Schroederichthys bivius) is a small (to 82 cm total Length) catshark that occurs in the Southeast Pacific and Southwest Atlantic from Valdivia, Chile, south around Cape Horn and north to southern Brazil. It is demersal on the continental shelf and upper slope at depths of 12-359 m (mostly <130 m). It is occasionally caught as bycatch of industrial and artisanal trawlers in Chile, Uruguay, Argentina, and the Falkland Islands (Malvinas). It is not typically utilized and is usually discarded dead. Overall, this catshark is caught throughout most of its range in small numbers. Its small size and presumably productive life history, combined with a lack of evidence of a population reduction, indicates that it is likely able to withstand limited exposure to fishing pressure. The population is suspected to be stable, therefore, the Narrowmouth Catshark is assessed as Least Concern.Fil: Dulvy, N. K.. University Fraser Simon; CanadáFil: Acuña, E.. Universidad Católica del Norte; ChileFil: Bustamante, C.. Universidad de Antofagasta; ChileFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Pompert, J.. Georgia Seafoods; Países BajosFil: Velez Zuazo, X.. Smithsonian Conservation Biology Institute; Estados Unido

Bathyraja magellanica, Magellan Skate

The Magellan Skate (Bathyraja magellanica) is a medium-sized (to 105 cm total length) skate that occurs in the Southeast Pacific Ocean from Puerto Montt, Chile to Cape Horn and in the Southwest Atlantic Ocean from San Matías Gulf to Tierra del Fuego, Argentina, off the Falkland Islands (Malvinas), and on the Burdwood Bank. It is demersal on the continental shelf and slope at depths of 30?600 m. It is captured in demersal trawl fisheries, however it has some refuge at depth and the population trend is suspected to be stable. Therefore, the Magellan Skate is assessed as Least Concern.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Dulvy, N. K.. University Fraser Simon; CanadáFil: Acuña, E.. Universidad Católica del Norte; ChileFil: Bustamante, C.. Universidad de Antofagasta; ChileFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Pompert, J.. Georgia Seafoods; Países BajosFil: Velez Zuazo, X.. Smithsonian Conservation Biology Institute; Estados Unido

Bathyraja meridionalis, Darkbelly Skate

The Darkbelly Skate (Bathyraja meridionalis) is a large (to 158 cm total length) that occurs in the Southeast Pacific Ocean off Magallanes Province, Chile, in the Southwest Atlantic Ocean from Buenos Aires to Tierra del Fuego, Argentina and westward to the Falkland Islands (Malvinas), and in the Antarctic Atlantic Ocean around the Shag Rocks and South Georgia. It is demersal on continental and insular shelves and slopes at depths of 65?2,240 m, and is captured in demersal trawl and longline fisheries targeting skates, Patagonian Toothfish, and other finfishes. It has substantial refuge at depth and its population is suspected to be stable. Therefore, the Darkbelly Skate is assessed as Least Concern.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Dulvy, N. K.. University Fraser Simon; CanadáFil: Acuña, E.. Universidad Católica del Norte; ChileFil: Bustamante, C.. Universidad de Antofagasta; ChileFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Pompert, J.. No especifíca;Fil: Velez Zuazo, X.. No especifíca

Bathyraja macloviana, Patagonian Skate

The Patagonian Skate (Bathyraja macloviana) is a small (to 71 cm total length) skate that occurs in the Southeast Pacific Ocean off Magallanes, Chile and in the Southwest Atlantic Ocean from Uruguay to Tierra del Fuego, Argentina and the Falkland Islands (Malvinas) and is demersal on the inner continental shelf and upper slope at depths of 50?515 m. It is captured in demersal trawl fisheries targeting skates, finfish, and squid. Skates are typically not recorded or managed at the species level. For example, in Argentina, there are no species-specific data, but catch-per-unit-effort of rays, in general, declined in the 1990s and early 2000s. In the Falkland Islands (Malvinas) target skate fishery, this species increased in relative abundance in catch compared to other larger species, but there are no data on absolute changes in density or biomass from that area. Little is known about the Chilean portion of the population, but it is captured there and is typically discarded dead. Overall, due to the level of inadequately managed fishing pressure it is exposed to, declines in skates in general in some parts of its range, and its relatively small size that likely makes it productive enough to withstand some fishing pressure, it is suspected that this skate has undergone a population reduction of 20?29% over the past three generations (28.5 years). Therefore, the Patagonian Skate is assessed as Near Threatened, nearly meeting the threshold for Vulnerable A2bd.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Dulvy, N. K.. University Fraser Simon; CanadáFil: Acuña, E.. Universidad Católica del Norte; ChileFil: Bustamante, C.. Universidad de Antofagasta; ChileFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J.M.. No especifíca;Fil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Paesch, L.. No especifíca;Fil: Pompert, J.. No especifíca;Fil: Velez Zuazo, X.. Smithsonian Conservation Biology Institute; Estados Unido

Tumor neuroectodérmico primitivo periférico de riñón, reporte de caso.

Introduction: Peripheral primitive neuroectodermal tumor of the kidney (PNETk) is a very aggressive rare disease that mainly affects young men. Case report: A 19-year-old male patient with symptoms of abdominal pain, hematuria and a palpable mass, the tomography shows a large left renal tumor. Conventional radical nephrectomy was performed and sent for pathology study plus histochemistry, resulting in PNETk. The patient then continued his oncology management for chemotherapy initially. Conclusion: The PNETk that we describe represents the first case reported in our country, it constitutes a unique clinical entity due to its rarity, being a challenge to make a diagnosis and its behavior and management is still based on case reports due to its infrequency.Introducción: El tumor neuroectodérmico primitivo periférico de riñón (PNETk) es una enfermedad rara muy agresivo que afecta mayormente a varones jóvenes. Reporte de caso: paciente varón de 19 años con cuadro clínico dolor abdominal, hematuria y masa palpable, en la tomografía se evidencia una enorme tumoración renal izquierda, Se le realiza nefrectomía radical convencional y se envía a estudio patológico más histoquímica resultando de PNETk. Luego paciente siguió su manejo por oncología para quimiterapia inicialmente. Conclusión: El PNETk que describimos representa el primer caso reportado en nuestro país, constituye una entidad clínica única por su rareza siendo un reto hacer diagnóstico y su comportamiento y manejo se sigue basando a reportes de casos debido a su poca frecuencia.

Bathyraja griseocauda, Graytail Skate

The Greytail Skate (Bathyraja griseocauda) is a large (to 157 cm total length) skate that occurs in the Southeast Pacific and Southwest Atlantic Oceans from Coquimbo, Chile south around Cape Horn and north to Uruguay, including the Falkland Islands (Malvinas), and is demersal on the mid-continental shelf and upper slope at depths of 30?1,010 m. It is captured in trawl and longline fisheries targeting skates, squid, shrimp, scallops, hake, and Patagonian Toothfish (Dissostichus eleginoides) that are inadequately managed and together operate throughout its range. Its large body size and relatively unproductive life history make it particularly vulnerable to overfishing. In the Southeast Pacific, this skate is captured and discarded dead in inadequately managed fisheries that operate throughout that portion of its range. In the Southwest Atlantic, where large skates are typically utilized or exported for human consumption, the catch-per-unit-effort (CPUE) for this skate in the Falkland Islands (Malvinas) multi-species skate fishery declined consistently and substantially from 120 to 23 kg/hr between 1994 and 2006, and increased to 70 kg/hr in 2013 due to a change in the area fished. Although no later data are available, this fishery continues and is still not managed at the species level. In Argentina, there are no species-specific data, but rays in general declined in CPUE in the 1990s and early 2000s. Overall, due to the level of inadequately managed fishing pressure it is exposed to across its range, its large size and relatively unproductive life history, the decline in CPUE of rays in general in some areas, and the noted decline in CPUE (although succeeded by an increase) of this species in the Falkland Islands, it is suspected that this skate has undergone a population reduction of 50?79% over the past three generations (69 years). Therefore, the Greytail Skate is assessed as Endangered A2bd.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Dulvy, N. K.. University Fraser Simon; CanadáFil: Acuña, E.. Universidad Católica del Norte; ChileFil: Bustamante, C.. Universidad de Antofagasta; ChileFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Paesch, L.. Direccion Nacional de Recursos Acuaticos ; UruguayFil: Pompert, J.. No especifíca;Fil: Velez Zuazo, X.. No especifíca