Role of rare earth elements and entropy on the anatase-to-rutile phase transformation of TiO2thin films deposited by ion beam sputtering

The role played by oxygen vacancies and rare earth (RE) elements in the anatase-to-rutile (A−R) phase transformation of titanium dioxide (TiO2) is still a matter of controversy. Here, we report the A−R transformation of TiO2 thin solid films as obtained by ion beam sputtering a RE-decorated titanium target in an oxygen-rich atmosphere. The samples correspond to undoped, single-doped (Sm, Tm, and Tb), and codoped (Sm:Tb, Sm:Tm, and Sm:Tb:Tm) TiO2 films. In the as-prepared form, the films are amorphous and contain ∼0.5 at. % of each RE. The structural modifications of the TiO2 films due to the RE elements and the annealing treatments in an oxygen atmosphere are described according to the experimental results provided by Raman scattering, X-ray photoelectron spectroscopy, and optical measurements. The A−R transformation depends on both the annealing temperature and the characteristics of the undoped, single-doped, and codoped TiO2 films. As reported in the literature, the A−R transformation can be inhibited or enhanced by the presence of impurities and is mostly related to energetic contributions. The experimental results were analyzed, considering the essential and stabilizing role of the entropy of mixing in the A−R transformation due to the introduction of more and multiple quantum states originated in vacancies and impurities in the anatase phase.Fil: Scoca, Diego L.S.. Universidade Estadual de Campinas; BrasilFil: Cemin, Felipe. Universidade Estadual de Campinas; BrasilFil: Aldabe, Sara Alfonsina. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Figueroa, Carlos A.. Universidade de Caxias Do Sul.; BrasilFil: Zanatta, Antonio R.. Universidade de Sao Paulo; BrasilFil: Alvarez, Fernando. Universidade Estadual de Campinas; Brasi

Synthesis, Characterization and Evaluation of the Cytotoxicity of Ni-Doped Zn(Se,S) Quantum Dots

Quantum dots (QDs) are semiconductor nanocrystals with desirable optical properties for biological applications, such as bioimaging and drug delivery. However, the potential toxicity of these nanostructures in biological systems limits their application. The present work is focused on the synthesis, characterization, and evaluation of the toxicity of water-stable Ni-doped Zn(Se,S) QDs. Also, the study of nondoped nanostructures was included for comparison purposes. Ni-doped nanostructures were produced from zinc chloride and selenide aqueous solutions in presence of 3-mercaptopropionic acid and Ni molar concentration of 0.001 M. In order to evaluate the potential cytoxicity of these doped nanostructures, human pancreatic carcinoma cells (PANC-1) were used as model. The cell viability was monitored in presence of Ni-doped Zn(Se,S) QDs at concentrations ranging from 0 μg/mL to 500 μg/mL and light excited Ni-doped Zn(Se,S) nanostructures were evaluated at 50 μg/mL. Results suggested that Ni-doped Zn(Se,S) nanostructures were completely safe to PANC-1 when concentrations from 0 μg/mL to 500 μg/mL were used, whereas non-doped nanostructures evidenced toxicity at concentrations higher than 200 μg/mL. Also, Ni-doped Zn(Se,S) QDs under light excitation do not evidence toxicity to PANC-1. These findings suggest strongly that Zn(Se,S) nanostructures doped with nickel could be used in a safe manner in light-driving biological applications and drug delivery

Aves asociadas al Aeropuerto Carriel Sur de Talcahuano, sur de Chile: evaluación de peligro aviario

Between the summer 2002 and 2005 was evaluated the richness and abundance of birds associated to the Carriel Sur Airport of Talcahuano and was estimated the collision risk representing each species for air navigation. Birds were counted in 10 count points distributed in different habitats around the landing runways. The collision risk was estimated by the Avian Hazard Index (AHI) which combines size, abundance and history of collisions of each species. During the study period 63 species were recorded, plus 10 aditional species were recorded after summer 2005. The most abundant species were the Grassland Yellow-Finch, Kelp Gull, Southern Lapwing Long-tailed Meadowlark (28%, 14%, 10%, 8% of all individual records). Excepting Kelp Gull, all remaining species exhibited seasonal cycles of abundance. The Kelp Gull showed multiyear outbreaks triggered. The species representing a higher collision risk for air navigation are the Kelp Gull (API = 36), Southern Lapwing (AHI = 24), South American Tern (AHI = 16), Black Vulture (AHI = 12), Neotropic Cormorant (AHI = 9) and Chimango Caracara (AHI = 8). However, the each species’ AHI varied temporally from very high to very low values according to changes in abundance. This study reflects the need for long-term assessments of changes in population size of bird species to better approximate the risk of bird-aircraft collisions.Entre el verano de 2002 y 2005 se evaluó la riqueza y abundancia de aves asociadas al Aeropuerto Carriel Sur de Talcahuano y se estimó el riesgo de colisión que representaría cada especie para la aeronavegación. Las aves fueron contabilizadas en 10 puntos de conteos distribuidos en distintos hábitats alrededor del las pistas de aterrizaje. El riesgo de colisión fue estimado mediante el índice de peligro aviario (IPA) el cual combina tamaño, abundancia e historial de colisiones de cada especie. Durante el periodo de estudio se registraron 63 especies, mas 10 especies que fueron registradas después del verano de 2005. Las especies más abundantes fueron el chirigüe, la gaviota dominicana, el queltehue y la loica (28%, 14%, 10%, 8% del total de registros individuales). Con excepción de la gaviota dominicana, todas las especies exhibieron ciclos estacionales de abundancia. La gaviota dominicana mostró irrupciones multianuales aparentemente por factores ambientales no bien determinados. Las especies que representarían un mayor riesgo de colisión para la aeronavegación son la gaviota dominicana (IPA = 36), el queltehue (IPA = 24), el gaviotín sudamericano (IPA = 16), el jote de cabeza negra (IPA = 12), el yeco (IPA = 9) y el tiuque (IPA = 8). Sin embargo, el IPA de cada especie varió temporalmente desde valores muy altos a valores muy bajos según los cambios de abundancia. Este estudio refleja la necesidad de evaluaciones de largo plazo de los cambios en el tamaño poblacional de especies de aves para una mejor aproximación del riesgo de colisiones aves-aeronaves

Mid-Infrared Laser Spectroscopy Applications in Process Analytical Technology: Cleaning Validation, Microorganisms, and Active Pharmaceutical Ingredients in Formulations

Mid-infrared (MIR) lasers are very high-brightness energy sources that are replacing conventional thermal sources (globars) in many infrared spectroscopy (IRS) techniques. Although not all laser properties have been exploited in depth, properties such as collimation, polarization, high brightness, and very high resolution have contributed to recast IRS tools. Applications of MIR laser spectroscopy to process analytical technology (PAT) are numerous and important. As an example, a compact grazing angle probe mount has allowed coupling to a MIR quantum cascade laser (QCL), enabling reflectance-absorbance infrared spectroscopy (RAIRS) measurements. This methodology, coupled to powerful multivariable analysis (MVA) routines of chemometrics and fast Fourier transform (FFT) preprocessing of the data resulted in very low limits of detection of active pharmaceutical ingredients (APIs) and high explosives (HEs) reaching trace levels. This methodology can be used to measure concentrations of surface contaminants for validation of cleanliness of pharmaceutical and biotechnology processing batch reactors and other manufacturing vessels. Another application discussed concerns the enhanced detection of microorganisms that can be encountered in pharmaceutical and biotechnology plants as contaminants and that could also be used as weapons of mass destruction in biological warfare. In the last application discussed, the concentration of APIs in formulations was determined by MIR laser spectroscopy and was cross validated with high-performance liquid chromatography

Coupling planktonic and benthic shifts during a bloom of Alexandrium catenella in southern Chile:Implications for bloom dynamics and recurrence

Cell abundances and distributions of Alexandrium catenella resting cysts in recent sediments were studied along time at two locations in the Chilean Inland Sea exposed to different oceanographic conditions: Low Bay, which is much more open to the ocean than the more interior and protected Ovalada Island. The bloom began in interior areas but maximum cyst concentrations were recorded in locations more open to the ocean, at the end of the Moraleda channel. Our results showed a time lapse of around 3 months from the bloom peak (planktonic population) until the number of resting cysts in the sediments reached a maximum. Three months later, less than 10% of the A. catenella cysts remained in the sediments. Maximum cyst numbers in the water column occurred one month after the planktonic peak, when no cells were present. The dinoflagellate assemblage at both study sites was dominated by heterotrophic cysts, except during the A. catenella bloom. CCA analyses of species composition and environmental factors indicated that the frequency of A. catenella blooms was associated with low temperatures, but not with salinity, chlorophyll a concentration, and predator presence (measured as clam biomass). However, resting cyst distribution was only related to cell abundance and location. The occurrence of A. catenella cysts was also associated with that of cysts from the toxic species Protoceratium reticulatum. By shedding light on the ecological requirements of A. catenella blooms, our observations support the relevance of encystment as a mechanism of bloom termination and show a very fast depletion of cysts from the sediments (<3 months), which suggest a small role for resting cyst deposits in the recurrence of A. catenella blooms in this area.Postprin

Tyr-Asp inhibition of glyceraldehyde 3-phosphate dehydrogenase affects plant redox metabolism

How organisms integrate metabolism with the external environment is a central question in biology. Here, we describe a novel regulatory small molecule, a proteogenic dipeptide Tyr-Asp, which improves plant tolerance to oxidative stress by directly interfering with glucose metabolism. Specifically, Tyr-Asp inhibits the activity of a key glycolytic enzyme, glyceraldehyde 3-phosphate dehydrogenase (GAPC), and redirects glucose toward pentose phosphate pathway (PPP) and NADPH production. In line with the metabolic data, Tyr-Asp supplementation improved the growth performance of both Arabidopsis and tobacco seedlings subjected to oxidative stress conditions. Moreover, inhibition of Arabidopsis phosphoenolpyruvate carboxykinase (PEPCK) activity by a group of branched-chain amino acid-containing dipeptides, but not by Tyr-Asp, points to a multisite regulation of glycolytic/gluconeogenic pathway by dipeptides. In summary, our results open the intriguing possibility that proteogenic dipeptides act as evolutionarily conserved small-molecule regulators at the nexus of stress, protein degradation, and metabolism.Fil: Moreno, Juan C.. Max Planck Institute Of Molecular Plant Physiology; AlemaniaFil: Rojas, Bruno Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Vicente, Rubén. Max Planck Institute Of Molecular Plant Physiology; AlemaniaFil: Gorka, Michal. Max Planck Institute Of Molecular Plant Physiology; AlemaniaFil: Matz, Timon. Max Planck Institute Of Molecular Plant Physiology; AlemaniaFil: Chodasiewicz, Monika. Max Planck Institute Of Molecular Plant Physiology; AlemaniaFil: Peralta?Ariza, Juan S.. Max Planck Institute Of Molecular Plant Physiology; AlemaniaFil: Zhang, Youjun. Max Planck Institute Of Molecular Plant Physiology; AlemaniaFil: Alseekh, Saleh. Max Planck Institute Of Molecular Plant Physiology; AlemaniaFil: Childs, Dorothee. European Molecular Biology Laboratory; AlemaniaFil: Luzarowski, Marcin. Max Planck Institute Of Molecular Plant Physiology; AlemaniaFil: Nikoloski, Zoran. Max Planck Institute Of Molecular Plant Physiology; AlemaniaFil: Zarivach, Raz. Ben Gurion University of the Negev; IsraelFil: Walther, Dirk. Max Planck Institute Of Molecular Plant Physiology; AlemaniaFil: Hartman, Matias Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Figueroa, Carlos Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Iglesias, Alberto Alvaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Fernie, Alisdair R.. Max Planck Institute Of Molecular Plant Physiology; AlemaniaFil: Skirycz, Aleksandra. Max Planck Institute Of Molecular Plant Physiology; Alemani

The Role of the Unfolded Protein Response on Renal Lipogenesis in C57BL/6 Mice.

Renal injury observed in several pathologies has been associated with lipid accumulation in the kidney. While it has been suggested that the accumulation of renal lipids depends on free fatty acids released from adipose tissue, it is not known whether in situ renal lipogenesis due to endoplasmic reticulum (ER) stress contributes to kidney injury. The aim of the present study was to elucidate the role of pharmacological ER stress in renal structure and function and its effect on renal lipid metabolism of C57BL/6 mice. ER stress increased serum creatinine and induced kidney structural abnormalities. Tunicamycin-administered mice developed hyperinsulinemia, augmented lipolysis and increased circulating leptin and adiponectin. Renal unfolded protein response (UPR) gene expression markers, the lipogenic transcription factor SREBP1 and the phosphorylation of eIF2α increased 8 h after tunicamycin administration. At 24 h, an increase in BiP protein content was accompanied by a reduction in p-eIF2α and increased SREBP-1 and FASn protein content, in addition to a significant increase in triglyceride content and a reduction in AMPK. Thus, ER stress induces in situ lipid synthesis, leading to renal lipid accumulation and functional alterations. Future pharmacological and/or dietary strategies must target renal ER stress to prevent kidney damage and the progression of metabolic diseases