Preparation, Structure and Spectroscopic Properties of NH 4 [Ln(S 2 CNH 2 ) 4 ] ⋅ H 2 O (Ln=La, Eu)

The title compounds were prepared under mild ambient conditions by a facile co-precipitation route. NH4[Eu(S2CNH2)4] ⋅ H2O (a) and NH4[La(S2CNH2)4] ⋅ H2O (b) crystallize isotypically in the monoclinic space group P21/c with a=8.4461(3), b=13.6367(3), c=16.2945(5) Å, β=103.759(2)° (for (a)), and a=8.50484(9), b=13.84476(16), c=16.20816(17) Å, β=103.7644(11)° for (b), respectively. The spectroscopic data reveal the presence of a ligand-to-metal charge transfer (LMCT) process of low energy in a and in the solid solutions NH4[La1−xEux(S2CNH2)4] ⋅ H2O (x=0.016 and 0.05). Despite of the consequent efficient luminescent quenching, it was possible to recorded excitation and emission spectra at room temperature. These spectra are characterized by narrow bands due to intraconfigurational-4f transitions of the Eu3+ ion. However, broad bands associated to the LMCT state were also observed, mainly for the solid solutions NH4[La1−xEux(S2CNH2)4] ⋅ H2O (x=0.016 and 0.05). Consequently, an intramolecular energy transfer mechanism is proposed, taking into account the role of the LMCT on the spectroscopic properties of dithiocarbamate complexes

Noncommutative field gas driven inflation

We investigate early time inflationary scenarios in an Universe filled with a dilute noncommutative bosonic gas at high temperature. A noncommutative bosonic gas is a gas composed of bosonic scalar field with noncommutative field space on a commutative spacetime. Such noncommutative field theories was recently introduced as a generalization of quantum mechanics on a noncommutative spacetime. As key features of these theories are Lorentz invariance violation and CPT violation. In the present study we use a noncommutative bosonic field theory that besides the noncommutative parameter $\theta$ shows up a further parameter $\sigma$. This parameter $\sigma$ controls the range of the noncommutativity and acts as a regulator for the theory. Both parameters play a key role in the modified dispersion relations of the noncommutative bosonic field, leading to possible striking consequences for phenomenology. In this work we obtain an equation of state $p=\omega(\sigma,\theta;\beta)\rho$ for the noncommutative bosonic gas relating pressure $p$ and energy density $\rho$, in the limit of high temperature. We analyse possible behaviours for this gas parameters $\sigma$, $\theta$ and $\beta$, so that $-1\leq\omega<-1/3$, which is the region where the Universe enters an accelerated phase.Comment: Reference added. Version to appear in Journal of Cosmology and Astroparticle Physics - JCA

The Ascent of the Abundant: How Mutational Networks Constrain Evolution

Evolution by natural selection is fundamentally shaped by the fitness landscapes in which it occurs. Yet fitness landscapes are vast and complex, and thus we know relatively little about the long-range constraints they impose on evolutionary dynamics. Here, we exhaustively survey the structural landscapes of RNA molecules of lengths 12 to 18 nucleotides, and develop a network model to describe the relationship between sequence and structure. We find that phenotype abundance—the number of genotypes producing a particular phenotype—varies in a predictable manner and critically influences evolutionary dynamics. A study of naturally occurring functional RNA molecules using a new structural statistic suggests that these molecules are biased toward abundant phenotypes. This supports an “ascent of the abundant” hypothesis, in which evolution yields abundant phenotypes even when they are not the most fit

Prevalence of potential drug-drug interactions in the intensive care unit of a Brazilian teaching hospital

Abstract Patients in intensive care unit are prescribed large numbers of drugs, highlighting the need to study potential Drug-Drug Interactions in this environment. The aim of this study was to delineate the prevalence and risk of potential drug-drug interactions between medications administered to patients in an ICU. This cross-sectional observational study was conducted during 12 months, in an adult ICU of a teaching hospital. Inclusion criteria were: prescriptions with 2 or more drugs of patients admitted to the ICU for > 24 hours and age of ≥18 years. Potential Drug-Drug Interactions were quantified and classified through MicromedexTM database. The 369 prescriptions included in this study had 205 different drugs, with an average of 13.04 ± 4.26 (mean ± standard deviation) drugs per prescription. Potential Drug-Drug Interactions were identified in 89% of these, with an average of 5.00 ± 5.06 interactions per prescription. Of the 405 different pairs of potentially interacting drugs identified, moderate and major interactions were present in 74% and 67% of prescriptions, respectively. The most prevalent interaction was between dipyrone and enoxaparin (35.8%), though its clinical occurrence was not observed in this study. The number of potential Drug-Drug Interactions showed significant positive correlations with the length of stay in the intensive care unit, and with the number of prescribed drugs. Acknowledging the high potential for Drug-Drug Interactions in the ICU represents an important step toward improving patient safety and best therapy results

Framing access to medicines in developing countries: an analysis of media coverage of Canada's Access to Medicines Regime

<p>Abstract</p> <p>Background</p> <p>In September 2003, the Canadian government committed to developing legislation that would facilitate greater access to affordable medicines for developing countries. Over the course of eight months, the legislation, now known as Canada's Access to Medicines Regime (CAMR), went through a controversial policy development process and the newspaper media was one of the major venues in which the policy debates took place. The purpose of this study was to examine how the media framed CAMR to determine how policy goals were conceptualized, which stakeholder interests controlled the public debate and how these variables related to the public policy process.</p> <p>Methods</p> <p>We conducted a qualitative content analysis of newspaper coverage of the CAMR policy and implementation process from 2003-2008. The primary theoretical framework for this study was framing theory. A total of 90 articles from 11 Canadian newspapers were selected for inclusion in our analysis. A team of four researchers coded the articles for themes relating to access to medicines and which stakeholders' voice figured more prominently on each issue. Stakeholders examined included: the research-based industry, the generic industry, civil society, the Canadian government, and developing country representatives.</p> <p>Results</p> <p>The most frequently mentioned themes across all documents were the issues of drug affordability, intellectual property, trade agreements and obligations, and development. Issues such as human rights, pharmaceutical innovation, and economic competitiveness got little media representation. Civil society dominated the media contents, followed far behind by the Canadian government, the research-based and generic pharmaceutical industries. Developing country representatives were hardly represented in the media.</p> <p>Conclusions</p> <p>Media framing obscured the discussion of some of the underlying policy goals in this case and failed to highlight issues which are now significant barriers to the use of the legislation. Using the media to engage the public in more in-depth exploration of the policy issues at stake may contribute to a more informed policy development process. The media can be an effective channel for those stakeholders with a weaker voice in policy deliberations to raise public attention to particular issues; however, the political and institutional context must be taken into account as it may outweigh media framing effects.</p

Critical mutation rate has an exponential dependence on population size for eukaryotic-length genomes with crossover

The critical mutation rate (CMR) determines the shift between survival-of-the-fittest and survival of individuals with greater mutational robustness (“flattest”). We identify an inverse relationship between CMR and sequence length in an in silico system with a two-peak fitness landscape; CMR decreases to no more than five orders of magnitude above estimates of eukaryotic per base mutation rate. We confirm the CMR reduces exponentially at low population sizes, irrespective of peak radius and distance, and increases with the number of genetic crossovers. We also identify an inverse relationship between CMR and the number of genes, confirming that, for a similar number of genes to that for the plant Arabidopsis thaliana (25,000), the CMR is close to its known wild-type mutation rate; mutation rates for additional organisms were also found to be within one order of magnitude of the CMR. This is the first time such a simulation model has been assigned input and produced output within range for a given biological organism. The decrease in CMR with population size previously observed is maintained; there is potential for the model to influence understanding of populations undergoing bottleneck, stress, and conservation strategy for populations near extinction

Combining experimental evolution with next-generation sequencing: a powerful tool to study adaptation from standing genetic variation

Evolve and resequence (E&R) is a new approach to investigate the genomic responses to selection during experimental evolution. By using whole genome sequencing of pools of individuals (Pool-Seq), this method can identify selected variants in controlled and replicable experimental settings. Reviewing the current state of the field, we show that E&R can be powerful enough to identify causative genes and possibly even single-nucleotide polymorphisms. We also discuss how the experimental design and the complexity of the trait could result in a large number of false positive candidates. We suggest experimental and analytical strategies to maximize the power of E&R to uncover the genotype–phenotype link and serve as an important research tool for a broad range of evolutionary questions.C Schlötterer, R Kofler, E Versace, R Tobler and SU Fransse