Fluorescence quantum efficiency of CdSe/CdS magic-sized quantum dots functionalized with carboxyl or hydroxyl groups

AbstractThe present letter reports the thermo-optical properties of functionalized CdSe/CdS magic-sized quantum dots (MSQDs) (sizes 1.9–2.3nm) with carboxyl (R–COOH) or hydroxyl (R–OH) groups in aqueous solutions. Atomic force microscopy and infrared transmittance measurements were used to determine the size of the QDs and to highlight the functionalized groups. Absolute nonradiative quantum efficiency (φ) and radiative quantum efficiency (η) values were determined by applying two techniques: thermal lens (TL) and an alternative method that analyzes the ring patterns generated in a laser beam due to thermally induced self-phase-modulation effects known as the conical diffraction. Fluorescence measurements corroborate the TL results

Características agronômicas, rendimento de óleo e proteína de canola em diferentes épocas de semeadura.

A cultura da canola vem ganhando espaço em sistemas de rotação de culturas. Entretanto, muitas informações sobre a época de plantio e adaptação de cultivares limitam seu cultivo a poucos produtores. O objetivo foi avaliar características fenológicas, fenométricas, produtividade, rendimento de proteína e óleo de seis híbridos de canola na região norte do estado do Rio Grande do Sul em duas épocas de semeadura. O delineamento experimental foi de blocos casualizados em esquema fatorial 6 x 2, seis híbridos de canola (Hyola 433, Hyola 50, Hyola 61, Hyola 76, Hyola 571 CL e Hyola 575 CL) em duas épocas de semeadura (08/05/2015 e 16/06/2015). Características fenológicas e fenométricas de cada material foram avaliadas diariamente durante a condução do trabalho. Produtividade, rendimento de óleo e proteína foram realizadas após a colheita, em laboratório. A melhor época de semeadura na região do Médio Alto Uruguai – RS foi a primeira época de semeadura, realizada em maio. O atraso da semeadura, independente do híbrido usado, acarreta perdas significativas no rendimento de grãos, e no teor de óleo. O híbrido Hyola 76 apresentou maior número de dias de floração, rendimento de grãos e óleo nas duas épocas de semeadura, em relação às demais cultivares utilizadas neste experimento

A comprehensive analysis of the genetic diversity and environmental adaptability in worldwide Merino and Merino-derived sheep breeds

BACKGROUND: To enhance and extend the knowledge about the global historical and phylogenetic relationships between Merino and Merino-derived breeds, 19 populations were genotyped with the OvineSNP50 BeadChip specifically for this study, while an additional 23 populations from the publicly available genotypes were retrieved. Three complementary statistical tests, Rsb (extended haplotype homozygosity between-populations), XP-EHH (cross-population extended haplotype homozygosity), and runs of homozygosity (ROH) islands were applied to identify genomic variants with potential impact on the adaptability of Merino genetic type in two contrasting climate zones. RESULTS: The results indicate that a large part of the Merino's genetic relatedness and admixture patterns are explained by their genetic background and/or geographic origin, followed by local admixture. Multi-dimensional scaling, Neighbor-Net, Admixture, and TREEMIX analyses consistently provided evidence of the role of Australian, Rambouillet and German strains in the extensive gene introgression into the other Merino and Merino-derived breeds. The close relationship between Iberian Merinos and other South-western European breeds is consistent with the Iberian origin of the Merino genetic type, with traces from previous contributions of other Mediterranean stocks. Using Rsb and XP-EHH approaches, signatures of selection were detected spanning four genomic regions located on Ovis aries chromosomes (OAR) 1, 6 and 16, whereas two genomic regions on OAR6, that partially overlapped with the previous ones, were highlighted by ROH islands. Overall, the three approaches identified 106 candidate genes putatively under selection. Among them, genes related to immune response were identified via the gene interaction network. In addition, several candidate genes were found, such as LEKR1, LCORL, GHR, RBPJ, BMPR1B, PPARGC1A, and PRKAA1, related to morphological, growth and reproductive traits, adaptive thermogenesis, and hypoxia responses. CONCLUSIONS: To the best of our knowledge, this is the first comprehensive dataset that includes most of the Merino and Merino-derived sheep breeds raised in different regions of the world. The results provide an in-depth picture of the genetic makeup of the current Merino and Merino-derived breeds, highlighting the possible selection pressures associated with the combined effect of anthropic and environmental factors. The study underlines the importance of Merino genetic types as invaluable resources of possible adaptive diversity in the context of the occurring climate changes

Antimalarial Activity and Mechanisms of Action of Two Novel 4-Aminoquinolines against Chloroquine-Resistant Parasites

Chloroquine (CQ) is a cost effective antimalarial drug with a relatively good safety profile (or therapeutic index). However, CQ is no longer used alone to treat patients with Plasmodium falciparum due to the emergence and spread of CQ-resistant strains, also reported for P. vivax. Despite CQ resistance, novel drug candidates based on the structure of CQ continue to be considered, as in the present work. One CQ analog was synthesized as monoquinoline (MAQ) and compared with a previously synthesized bisquinoline (BAQ), both tested against P. falciparum in vitro and against P. berghei in mice, then evaluated in vitro for their cytotoxicity and ability to inhibit hemozoin formation. Their interactions with residues present in the NADH binding site of P falciparum lactate dehydrogenase were evaluated using docking analysis software. Both compounds were active in the nanomolar range evaluated through the HRPII and hypoxanthine tests. MAQ and BAQ derivatives were not toxic, and both compounds significantly inhibited hemozoin formation, in a dose-dependent manner. MAQ had a higher selectivity index than BAQ and both compounds were weak PfLDH inhibitors, a result previously reported also for CQ. Taken together, the two CQ analogues represent promising molecules which seem to act in a crucial point for the parasite, inhibiting hemozoin formation

Selection Signatures in Worldwide Sheep Populations

The diversity of populations in domestic species offers great opportunities to study genome response to selection. The recently published Sheep HapMap dataset is a great example of characterization of the world wide genetic diversity in sheep. In this study, we re-analyzed the Sheep HapMap dataset to identify selection signatures in worldwide sheep populations. Compared to previous analyses, we made use of statistical methods that (i) take account of the hierarchical structure of sheep populations, (ii) make use of linkage disequilibrium information and (iii) focus specifically on either recent or older selection signatures. We show that this allows pinpointing several new selection signatures in the sheep genome and distinguishing those related to modern breeding objectives and to earlier post-domestication constraints. The newly identified regions, together with the ones previously identified, reveal the extensive genome response to selection on morphology, color and adaptation to new environments