Degradation study of polypropylene (PP) and bioriented polypropylene (BOPP) in the environment

Polymers are vastly employed for numerous purposes in different industrial segments and generate soaring quantities of discarding in the environment. This research analyzed the degradability/biodegradability of polypropylene films (PP) and Bioriented polypropylene (BOPP) polymers after 11 months interred in the São Giácomo landfill in Caxias do Sul. Comparing the buried PP film to a sample of virgin PP, two peaks of degrading activity appeared at the TG curve as well as structure modification typified by occurrence of new absorption bands at FTIR, which can be credited to changes in crystallinity. Thermal analysis carried out on the buried PP and BOPP showed decreases in the percentage of crystallinity due to chain scission. The major reduction was observed in the PP, since its crystallinity is a consequence of polymerization instead of chain orientation processes, as in BOPP. Cracks and erosion of the polymer surface were detected in both PP and BOPP, indicating degrading processes by microorganisms

Role of micellar interface in the synthesis of chitosan nanoparticles formulated by reverse micellar method

Chitosan nanoparticles (Ch-NPs) have been extensively studied due to their wide applicability. The reverse micellar method has attracted special attention as a way to synthesize them, since it makes it possible to obtain size-controlled particles. This procedure involves the chitosan crosslinking reaction into polar cores of reverse micelles (RMs). Previous studies using sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT) RMs as nanoreactors showed that by changing the reagent concentration and RM water content, the final particle size can be adjusted. To gain insight into this method, we studied the effect of the micellar interface on the synthesis of Ch-NPs. Both benzyl-n-hexadecyldimethylammonium chloride (BHDC) and AOT RMs were assessed, since there are remarkable differences between their interfacial water entrapped structure. Ch-NPs were characterized by FT-IR spectroscopy, Dynamic Light Scattering, and Scanning Electron Microscopy. Simulation studies by molecular theory were also performed. On the other hand, Ch-NPs obtained under different conditions were assessed in terms of their ability to solubilize curcumin, whose numerous therapeutic properties are somewhat countered by its poor solubility in water. The results show that Ch-NPs can be obtained from AOT and BHDC RMs by the reverse micellar method. The crosslinking reaction takes place in the micellar interface, and is more effective in AOT RMs. This difference in effectiveness can be attributed to the different positions Ch acquires in each of the two RMs tested. Finally, the NPs notably enhance the water solubility of curcumin, and particle size is the main determining factor for encapsulation efficiency.Fil: Orellano, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Transferencia de Villa María. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Longo, Gabriel Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Porporatto, Carina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones y Transferencia de Villa María. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; ArgentinaFil: Correa, Nestor Mariano. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Falcone, Ruben Dario. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; Argentin

Prognostic utility of cell cycle progession score in men with prostate cancer after primary external beam radiation therapy. In regard to Freedland et al.

Tropical regions, especially the Amazon region, account for large emissions of methane (CH4). Here, we present CH4 observations from two airborne campaigns conducted within the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) project in the Amazon basin in November 2008 (end of the dry season) and May 2009 (end of the wet season). We performed continuous measurements of CH4 onboard an aircraft for the first time in the Amazon region, covering the whole Amazon basin with over 150 vertical profiles between altitudes of 500 m and 4000 m. The observations support the finding of previous ground-based, airborne, and satellite measurements that the Amazon basin is a large source of atmospheric CH4. Isotope analysis verified that the majority of emissions can be attributed to CH4 emissions from wetlands, while urban CH4 emissions could be also traced back to biogenic origin. A comparison of five TM5 based global CH4 inversions with the observations clearly indicates that the inversions using SCIAMACHY observations represent the BARCA observations best. The calculated CH4 flux estimate obtained from the mismatch between observations and TM5-modeled CH4 fields ranges from 36 to 43 mg m−2 d−1 for the Amazon lowland region

Methane airborne measurements and comparison to global models during BARCA

Tropical regions, especially the Amazon region, account for large emissions of methane (CH4). Here, we present CH4 observations from two airborne campaigns conducted within the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) project in the Amazon basin in November 2008 (end of the dry season) and May 2009 (end of the wet season). We performed continuous measurements of CH4 onboard an aircraft for the first time in the Amazon region, covering the whole Amazon basin with over 150 vertical profiles between altitudes of 500 m and 4000 m. The observations support the finding of previous ground-based, airborne, and satellite measurements that the Amazon basin is a large source of atmospheric CH4.Isotope analysis verified that the majority of emissions can be attributed to CH4 emissions from wetlands, while urban CH4 emissions could be also traced back to biogenic origin. A comparison of five TM5 based global CH4 inversions with the observations clearly indicates that the inversions using SCIAMACHY observations represent the BARCA observations best. The calculated CH4 flux estimate obtained from the mismatch between observations and TM5-modelled CH4 fields ranges from 29 to 34 mg m-2 d-1 for the Amazon lowland region.JRC.H.2-Air and Climat