Synthesis and optoelectronic properties of new Fluorene-2,5-Diaryl-1,3,4-Oxadiazole hybrid materials

Novel fluorene and spirobifluorene-2,5-diaryl-l,3,4-oxadiazole hybrids 165 and 171, respectively, have been synthesised by Suzuki cross-coupling methodology. Pyridine analogues of 165 and 171,184 and 185, respectively, were also synthesised. Further extension of the π-electron framework was achieved via Wittig reaction to afford compound 177. Single layer organic light emitting devices (OLED)s using blends of MEH-PPV as the emissive material with electron transport (ET) materials 165, 171, 177， 184 and 185 have been fabricated. For all the devices studied electroluminescence (EL) originated exclusively from the MEH-PPV with external quantum efficiencies (EQE)s greatly enhanced (>two orders of magnitude) compared to pure MEH-PPV devices. The incorporation of pyridine in compounds 184 and 185 considerably enhanced the electron affinity of the systems compared to compounds 165 and 171. For a device incorporating PEDOT:PSS in the configuration ITO/PEDOT:PSS/MEH-PPV-185 (30 ： 70% by weight)/Ca/Al an EQE of ca. 0.6% and a luminance efficiency of 1.2 cd A—i at 10.5 V was achieved

Molecular phylogenies map to biogeography better than morphological ones

Phylogenetic relationships are inferred principally from two classes of data: morphological and molecular. Most current phylogenies of extant taxa are inferred from molecules, and when morphological and molecular trees conflict the latter are often preferred. Although supported by simulations, the superiority of molecular trees has never been assessed empirically. Here we test phylogenetic accuracy using two independent data sources: biogeographical distributions and fossil first occurrences. For 48 pairs of morphological and molecular trees, we show that, on average, molecular trees provide a better fit to biogeographical data than their morphological counterparts, and that, biogeographical congruence increases over research time. We find no significant differences in stratigraphical congruence between morphological and molecular trees. These findings have implications for understanding homoplasy in morphological data sets, the utility of morphology as a test of molecular hypotheses, and the implications of analysing fossil groups for which molecular data are unavailable

Oral immunization with a dam mutant of Yersinia pseudotuberculosis protects against plague.

Inactivation of the gene encoding DNA adenine methylase (dam) has been shown to attenuate some pathogens such as Salmonella enterica serovar Typhimurium and is a lethal mutation in others such as Yersinia pseudotuberculosis strain YPIII. In this study the dam methylase gene in Yersinia pseudotuberculosis strain IP32953 was inactivated. Unlike the wild-type, DNA isolated from the mutant could be digested with MboI, which is consistent with an altered pattern of DNA methylation. The mutant was sensitive to bile salts but not to 2-aminopurine. The effect of dam inactivation on gene expression was examined using a DNA microarray. In BALB/c mice inoculated orally or intravenously with the dam mutant, the median lethal dose (MLD) was at least 10(6)-fold higher than the MLD of the wild-type. BALB/c mice inoculated with the mutant were protected against a subcutaneous challenge with 100 MLDs of Yersinia pestis strain GB and an intravenous challenge with 300 MLDs of Y. pseudotuberculosis IP32953

The Role of Alcohol in Child Sexual Exploitation: Developing a model to inform practice

Alcohol has been linked repeatedly to child sexual exploitation (CSE) in the media and in reports of CSE enquiries. However, there is a lack of research that focuses on this relationship in any depth and especially research that considers its implications for alcohol service providers. This study aims to develop a better understanding of the nature and extent of the relationship between alcohol and CSE and the implications of alcohol-related CSE for alcohol service interventions, principally from the perspective of service providers but also through the voices of a small number of young people. Two qualitative approaches have been adopted to explore the role of alcohol in CSE and to establish what current intervention provision looks like: semi-structured interviews with alcohol and drug workers and CSE workers and a focus group to incorporate the voices of young people. Thematic analysis (Braun and Clarke, 2006) is used to highlight the key themes discussed by both professionals and young people. This is the first study of its kind to focus specifically on the relationship between alcohol and CSE and contributes to the evidence base in several areas. It demonstrates the complexity of the roles that alcohol can play leading up to, during, and after sexual exploitation. Alcohol is used by perpetrators during the grooming process; it is used by young people both during and after CSE, as part of an emotional response to the trauma they are experiencing. However, alcohol is also a ‘normal’ part of growing up for many young people, which adds complexity to the assessment of, and response to, alcohol-related CSE. An explanatory model is presented to demonstrate the role of alcohol in CSE. Supporting young people around alcohol and CSE can be challenging, not just because of the complexity of this relationship but also because of difficulties getting young people to engage in the support process. This research is the first of its kind to speak to alcohol service providers specifically on this topic, to gain an insight into their response to alcohol-related CSE and to identify how young people experiencing it can be better supported

Why should we investigate the morphological disparity of plant clades?

Background Disparity refers to the morphological variation in a sample of taxa, and is distinct from diversity or taxonomic richness. Diversity and disparity are fundamentally decoupled; many groups attain high levels of disparity early in their evolution, while diversity is still comparatively low. Diversity may subsequently increase even in the face of static or declining disparity by increasingly fine sub-division of morphological ‘design’ space (morphospace). Many animal clades reached high levels of disparity early in their evolution, but there have been few comparable studies of plant clades, despite their profound ecological and evolutionary importance. This study offers a prospective and some preliminary macroevolutionary analyses. Methods Classical morphometric methods are most suitable when there is reasonable conservation of form, but lose traction where morphological differences become greater (e.g. in comparisons across higher taxa). Discrete character matrices offer one means to compare a greater diversity of forms. This study explores morphospaces derived from eight discrete data sets for major plant clades, and discusses their macroevolutionary implications. Key Results Most of the plant clades in this study show initial, high levels of disparity that approach or attain the maximum levels reached subsequently. These plant clades are characterized by an initial phase of evolution during which most regions of their empirical morphospaces are colonized. Angiosperms, palms, pines and ferns show remarkably little variation in disparity through time. Conifers furnish the most marked exception, appearing at relatively low disparity in the latest Carboniferous, before expanding incrementally with the radiation of successive, tightly clustered constituent sub-clades. Conclusions Many cladistic data sets can be repurposed for investigating the morphological disparity of plant clades through time, and offer insights that are complementary to more focused morphometric studies. The unique structural and ecological features of plants make them ideally suited to investigating intrinsic and extrinsic constraints on disparity

What limits the morphological disparity of clades?

The morphological disparity of species within major clades shows a variety of trajectory patterns through evolutionary time. However, there is a significant tendency for groups to reach their maximum disparity relatively early in their histories, even while their species richness or diversity is comparatively low. This pattern of early high-disparity suggests that there are internal constraints (e.g. developmental pleiotropy) or external restrictions (e.g. ecological competition) upon the variety of morphologies that can subsequently evolve. It has also been demonstrated that the rate of evolution of new character states decreases in most clades through time (character saturation), as does the rate of origination of novel bodyplans and higher taxa. Here, we tested whether there was a simple relationship between the level or rate of character state exhaustion and the shape of a clade's disparity profile: specifically, its centre of gravity (CG). In a sample of 93 extinct major clades, most showed some degree of exhaustion, but all continued to evolve new states up until their extinction. Projection of states/steps curves suggested that clades realized an average of 60% of their inferred maximum numbers of states. Despite a weak but significant correlation between overall levels of homoplasy and the CG of clade disparity profiles, there were no significant relationships between any of our indices of exhaustion curve shape and the clade disparity CG. Clades showing early high-disparity were no more likely to have early character saturation than those with maximum disparity late in their evolution

A novel vaccine platform using glucan particles for induction of protective responses against Francisella tularensis and other pathogens

Vaccines are considered the bedrock of preventive medicine. However, for many pathogens, it has been challenging to develop vaccines that stimulate protective, long-lasting immunity. We have developed a novel approach using beta-1,3-D-glucans (BGs), natural polysaccharides abundantly present in fungal cell walls, as a biomaterial platform for vaccine delivery. BGs simultaneously provide for receptor-targeted antigen delivery to specialized antigen-presenting cells together with adjuvant properties to stimulate antigen-specific and trained non-specific immune responses. This review focuses on various approaches of using BG particles (GPs) to develop bacterial and fungal vaccine candidates. A special case history for the development of an effective GP tularaemia vaccine candidate is highlighted

High-throughput analysis of Yersinia pseudotuberculosis gene essentiality in optimised in vitro conditions, and implications for the speciation of Yersinia pestis.

BACKGROUND: Yersinia pseudotuberculosis is a zoonotic pathogen, causing mild gastrointestinal infection in humans. From this comparatively benign pathogenic species emerged the highly virulent plague bacillus, Yersinia pestis, which has experienced significant genetic divergence in a relatively short time span. Much of our knowledge of Yersinia spp. evolution stems from genomic comparison and gene expression studies. Here we apply transposon-directed insertion site sequencing (TraDIS) to describe the essential gene set of Y. pseudotuberculosis IP32953 in optimised in vitro growth conditions, and contrast these with the published essential genes of Y. pestis. RESULTS: The essential genes of an organism are the core genetic elements required for basic survival processes in a given growth condition, and are therefore attractive targets for antimicrobials. One such gene we identified is yptb3665, which encodes a peptide deformylase, and here we report for the first time, the sensitivity of Y. pseudotuberculosis to actinonin, a deformylase inhibitor. Comparison of the essential genes of Y. pseudotuberculosis with those of Y. pestis revealed the genes whose importance are shared by both species, as well as genes that were differentially required for growth. In particular, we find that the two species uniquely rely upon different iron acquisition and respiratory metabolic pathways under similar in vitro conditions. CONCLUSIONS: The discovery of uniquely essential genes between the closely related Yersinia spp. represent some of the fundamental, species-defining points of divergence that arose during the evolution of Y. pestis from its ancestor. Furthermore, the shared essential genes represent ideal candidates for the development of novel antimicrobials against both species