Stepwise Filtering of the Internal Layers of Dendrimers by Transverse-Relaxation-Edited NMR

The characteristic distribution of transverse relaxation times (T2) within dendrimers (shorter values at the core than the periphery) can be exploited in T2-edited 1D and 2D NMR experiments for the stepwise filtering of internal nuclei according to their topology within the dendritic structure. The resulting filtered spectra, which can be conceived as corresponding to virtual hollow dendrimers, benefit from reduced signal overlap, thus facilitating signal assignment and characterization. The generality of the method as a powerful tool in structural and end-group analysis has been confirmed with various dendritic families and nuclei (1H, 13C, 31P)This work was financially supported by the Spanish Government (CTQ2009-10963, CTQ2012-34790, CTQ2009-14146-C02-02, CTQ2012-33436) and the Xunta de Galicia (10CSA209021PR and CN2011/037). L.F.P. thanks the Portuguese Foundation for Science and Technology (FCT MCTES) for a Ph.D. grant (SFRH/BD/37341/2007)S

Predicting PSR Filters by Transverse Relaxation Enhancements

The paramagnetic spin relaxation (PSR) filter allows the suppression of the NMR resonances of individual components in mixtures according to their Gd3+-complexing ability. The difficulty in predicting this property hampers, however, the widespread application of this filter. Herein we describe that the PSR filter is dominated by the transverse relaxation enhancement (R2p) experienced by nuclei in the presence of Gd3+, so that R2p represents a reliable predictive tool of suppression in the 1D and 2D PSR filter of complex mixtures. The robustness of R2p as a predictive tool in PSR filters has been demonstrated at different magnetic fields and for the 1H, 13C, COSY, and HMQC filtering of commercial multicomponent compositions, including beverages and drugsThis work was financially supported by the Spanish Government (CTQ2012-34790, CTQ2012-33436) and the Xunta de Galicia (CN2011/037). L.F.P. thanks the Portuguese Foundation for Science and Technology (FCT MCTES) for a Ph.D. grant (SFRH/BD/37341/2007)S

Nanomineralogy of evaporative precipitation of efflorescent compounds from coal mine drainage

Efflorescent nanophases (NPs) are found as a transitory accumulation of potentially hazardous elements (PHEs), particularly in tropical climates. The central objective of this study was to investigate the distribution of PHEs with NPs through the evaporative formation structures (EFS) of enormously PHEs-rich coal-mine drainages (CMD). The EFS were studied in natural coal mine drainage for five months in order to determine their geochemical and ecological structures and to assess their position in the reduction of PHEs in nature. The largest coal-fired power plant in South America, located in south Brazil, is used as an example of such a problem. In this work, a novel methodology for the analysis of PHEs in CMD precipitates is proposed for this affected coal area. The analytical method, combining X-Ray Diffraction (XRD) and advanced electron microscopies, shows the importance of nanomineralogy in understanding different circumstances of coal contamination. Several ultrafine-nanoparticles (UNPs) were identified in the sampled soils and river sediments together with the PHEs. A decrease in PHEs was identified in association with UNPs. However, further investigations are required with regard to the mobility of PHEs in water, atmosphere, soils, and sediments. The EPS was thoroughly studied, acquiring suitable understanding with investigational facts for Ca and Fe-sulphates, pickeringite, and several amorphous phases

Sacral Fractures and Associated Injuries.

STUDY DESIGN: Literature review. OBJECTIVE: The aim of this review is to describe the injuries associated with sacral fractures and to analyze their impact on patient outcome. METHODS: A comprehensive narrative review of the literature was performed to identify the injuries associated with sacral fractures. RESULTS: Sacral fractures are uncommon injuries that result from high-energy trauma, and that, due to their rarity, are frequently underdiagnosed and mistreated. Only 5% of sacral fractures occur in isolation. Injuries most often associated with sacral fractures include neurologic injuries (present in up to 50% of sacral fractures), pelvic ring disruptions, hip and lumbar spine fractures, active pelvic/ abdominal bleeding and the presence of an open fracture or significant soft tissue injury. Diagnosis of pelvic ring fractures and fractures extending to the lumbar spine are key factors for the appropriate management of sacral fractures. Importantly, associated systemic (cranial, thoracic, and abdominopelvic) or musculoskeletal injuries should be promptly assessed and addressed. These associated injuries often dictate the management and eventual outcome of sacral fractures and, therefore, any treatment algorithm should take them into consideration. CONCLUSIONS: Sacral fractures are complex in nature and often associated with other often-missed injuries. This review summarizes the most relevant associated injuries in sacral fractures and discusses on their appropriate management

Obtenção de quitina a partir de carapaças de siri (Maia squinado): uso de um planejamento experimental na etapa de desmineralização.

A quitina, b-(1-4)-N-acetil-D-glucosamina, é encontrada nos exoesqueletos de crustáceos, na parede celular de fungos e em outros materiais biológicos, e é através dela que se obtém a quitosana, b-(1-4)-D-glucosamina. A cidade portuária do Rio Grande/RS produz uma grande quantidade de resíduos de pescado, devido à grande concentração de indústrias pesqueiras. Como a biodegradação desses resíduos é muito lenta, o acúmulo dos mesmos torna-se um problema ambiental. O siri apresenta em sua composição 15 a 20% de quitina e um alto teor de cinzas. Este trabalho tem por objetivo a obtenção de quitina a partir de carapaças de siri, através das etapas de desmineralização, desproteinização e desodorização. Devido ao alto teor de cinzas na carapaça de siri, foi feito um planejamento experimental do tipo fatorial completo, a fim de determinar a melhor condição para a etapa de desmineralização. Os fatores de estudo foram o tempo, a concentração e a relação solução ácido/carapaça. A melhor condição de desmineralização foi no tempo de 14h, na concentração de 7% v/v, e na relação de 4:1 de solução ácido/carapaça. A quitina obtida apresentou um grau de pureza de aproximadamente 99% (umidade 4% b.u.) e um rendimento de aproximadamente 17% em relação à matéria-prima

Metal Coordination and Biological Screening of a Schiff Base Derived from 8-Hydroxyquinoline and Benzothiazole

Designing new metallodrugs for anticancer therapy is a driving force in the scientific community. Aiming to contribute to this field, we hereby report the development of a Schiff base (H2L) derived from the condensation of 2-carbaldehyde-8-hydroxyquinoline with 2-hydrazinobenzothiazole and its complexation with transition metal ions. All compounds were characterised by analytical and spectroscopic techniques, which disclosed their structure: [Cu(HL)Cl], [Cu(HL)2], [Ni(HL)(acetate)], [Ni(HL)2], [Ru(HL)Cl(DMSO)], [VO(HL)2] and [Fe(HL)2Cl(H2O)]. Different binding modes were proposed, showing the ligand’s coordination versatility. The ligand proton dissociation constants were determined, and the tested compounds showed high lipophilicity and light sensitivity. The stability of all complexes in aqueous media and their ability to bind to albumin were screened. Based on an antiproliferative in vitro screening, [Ni(HL)(acetate)] and [Ru(HL)Cl(DMSO)] were selected for further studies aiming to investigate their mechanisms of action and therapeutic potential towards colon cancer. The complexes displayed IC50 < 21 μM towards murine (CT-26) and human (HCT-116) colon cancer cell lines. Importantly, both complexes exhibited superior antiproliferative properties compared to the clinically approved 5-fluorouracil. [Ni(HL)(acetate)] induced cell cycle arrest in S phase in CT-26 cells. For [Ru(HL)Cl(DMSO)] this effect was observed in both colon cancer cell lines. Additionally, both compounds significantly inhibited cell migration particularly in the human colon cancer cell line, HCT-116. Overall, the therapeutic potential of both metal complexes was demonstrated

Synthesis, structural characterization and properties of water-soluble N-(gamma-propanoyl-amino acid)-chitosans

Water-soluble peptide-chitosans were obtained by reaction of low-molecular-weight chitosan, having a low degree of acetylation, with peptide substituents under mild conditions. These peptide substituents were prepared by standard peptide chemistry from 3-bromopropanoic acid and tert-butyl esters of the alpha-amino acids glycine and phenylalanine. The structure of the new peptide-chitosan polymers was confirmed by proton nuclear magnetic resonance and infrared spectroscopy. The thermotropic and morphological properties of both the new peptide-chitosans and two other analogues, derived from valine and aspartic acid [synthesis reported in Batista. M. K. S., Pinto, L. F., Gomes, C. A. R., & Gomes, P. (2006). Novel highly soluble peptide-chitosan polymers: Synthesis and spectral characterization. Carbohlydrate Polymers, 64, 299-305], were evaluated by differential scanning calorimetry and scanning electron microscopy, respectively. As compared to the parent unmodified chitosan, the four peptide-chitosans had higher thermo-sensitivity, porosity and water-holding capacity, and such effects increased with the hydrophilicity of the peptide ligands. The acid-base properties of the four peptide-chitosans were also evaluated by potentiometric techniques and reflected the influence of the inserted ligands on the polymers' acidity constants. It was also possible to confirm the polymers' solubility over the 2-10 pH range. Overall. these polymers present physico-chemical properties that make them promising candidates for the design of novel drug delivery systems