162 research outputs found
Excessive Yawning and SSRI Therapy
As we become more experienced with the long-term use of selective serotonin reuptake inhibitors (SSRIs), more subtle side-effects may become evident. Clinicians may be aware of yawning as a side-effect of antidepressant therapy, however sparse literature exists on the topic. We present two cases in which excessive daytime yawning was associated with SSRI treatment
The geometry of nonlinear least squares with applications to sloppy models and optimization
Parameter estimation by nonlinear least squares minimization is a common
problem with an elegant geometric interpretation: the possible parameter values
of a model induce a manifold in the space of data predictions. The minimization
problem is then to find the point on the manifold closest to the data. We show
that the model manifolds of a large class of models, known as sloppy models,
have many universal features; they are characterized by a geometric series of
widths, extrinsic curvatures, and parameter-effects curvatures. A number of
common difficulties in optimizing least squares problems are due to this common
structure. First, algorithms tend to run into the boundaries of the model
manifold, causing parameters to diverge or become unphysical. We introduce the
model graph as an extension of the model manifold to remedy this problem. We
argue that appropriate priors can remove the boundaries and improve convergence
rates. We show that typical fits will have many evaporated parameters. Second,
bare model parameters are usually ill-suited to describing model behavior; cost
contours in parameter space tend to form hierarchies of plateaus and canyons.
Geometrically, we understand this inconvenient parametrization as an extremely
skewed coordinate basis and show that it induces a large parameter-effects
curvature on the manifold. Using coordinates based on geodesic motion, these
narrow canyons are transformed in many cases into a single quadratic, isotropic
basin. We interpret the modified Gauss-Newton and Levenberg-Marquardt fitting
algorithms as an Euler approximation to geodesic motion in these natural
coordinates on the model manifold and the model graph respectively. By adding a
geodesic acceleration adjustment to these algorithms, we alleviate the
difficulties from parameter-effects curvature, improving both efficiency and
success rates at finding good fits.Comment: 40 pages, 29 Figure
Global utilization of low-dose corticosteroids in severe sepsis and septic shock: a report from the PROGRESS registry
The benefits and use of low-dose corticosteroids (LDCs) in severe sepsis and septic shock remain controversial. Surviving sepsis campaign guidelines suggest LDC use for septic shock patients poorly responsive to fluid resuscitation and vasopressor therapy. Their use is suspected to be wide-spread, but paucity of data regarding global practice exists. The purpose of this study was to compare baseline characteristics and clinical outcomes of patients treated or not treated with LDC from the international PROGRESS (PROmoting Global Research Excellence in Severe Sepsis) cohort study of severe sepsis.Journal ArticleMulticenter StudyResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe
Elucidating the significance of copper and nitrate speciation in Cu-SSZ-13 for N2O formation during NH3-SCR
Unwanted N2O formation is a problem that has been noted in selective catalytic reduction (SCR) where copper zeolite catalysts are utilized. With its immense global warming potential and long-term stability, elevated atmospheric N2O has already been identified as a future challenge in the war on climate change. This paper explores the phenomenon of N2O formation during NH3-SCR over Cu-SSZ-13 catalysts, which are currently commercialized in automotive emissions control systems, and proposes a link between N2O production and the local copper environment found within the zeolite. To achieve this, a comparison is made between two Cu-SSZ-13 samples with different copper co-ordinations produced via different synthesis methods. A combination of synchrotron X-ray absorption near-edge spectroscopy, UV–vis, Raman, and density functional theory (DFT) is used to characterize the nature of copper species present within each sample. Synchrotron IR microspectroscopy is then used to compare their behavior during SCR under operando conditions and monitor the evolution of nitrate intermediates, which, along with further DFT, informs a mechanistic model for nitrate decomposition pathways. Increased N2O production is seen in the Cu-SSZ-13 sample postulated to contain a linear Cu species, providing an important correlation between the catalytic behavior of Cu-zeolites and the nature of their metal ion loading and speciation
Health inequalities, physician citizens and professional medical associations: an Australian case study
<p>Abstract</p> <p>Background</p> <p>As socioeconomic health inequalities persist and widen, the health effects of adversity are a constant presence in the daily work of physicians. Gruen and colleagues suggest that, in responding to important population health issues such as this, defining those areas of professional obligation in contrast to professional aspiration should be on the basis of evidence and feasibility. Drawing this line between obligation and aspiration is a part of the work of professional medical colleges and associations, and in doing so they must respond to members as well as a range of other interest groups. Our aim was to explore the usefulness of Gruen's model of physician responsibility in defining how professional medical colleges and associations should lead the profession in responding to socioeconomic health inequalities.</p> <p>Methods</p> <p>We report a case study of how the Royal Australian College of General Practitioners is responding to the issue of health inequalities through its work. We undertook a consultation (80 interviews with stakeholders internal and external to the College and two focus groups with general practitioners) and program and policy review of core programs of College interest and responsibility: general practitioner training and setting of practice standards, as well as its work in public advocacy.</p> <p>Results</p> <p>Some strategies within each of these College program areas were seen as legitimate professional obligations in responding to socioeconomic health inequality. However, other strategies, while potentially professional obligations within Gruen's model, were nevertheless contested. The key difference between these lay in different moral orientations. Actions where agreement existed were based on an ethos of care and compassion. Actions that were contested were based on an ethos of justice and human rights.</p> <p>Conclusion</p> <p>Colleges and professional medical associations have a role in explicitly leading a debate about values, engaging both external stakeholder and practicing member constituencies. This is an important and necessary step in defining an agreed role for the profession in addressing health inequalities.</p
Continuous-flow transfer hydrogenation of benzonitrile using formate as a safe and sustainable source of hydrogen â€
The continuous catalytic transfer hydrogenation of benzonitrile to benzylamine is demonstrated using a palladium on carbon catalyst with triethylammonium formate as reducing agent. Solvent choice was critical in overcoming rapid catalyst deactivation. A 15-fold increase in catalyst productivity was observed in flow compared to batch, which was achieved using an ethanol–water solvent in combination with intermittent catalyst regeneration by washing with water
Progressive, Transgenerational Changes in Offspring Phenotype and Epigenotype following Nutritional Transition
Induction of altered phenotypes during development in response to environmental input involves epigenetic changes. Phenotypic traits can be passed between generations by a variety of mechanisms, including direct transmission of epigenetic states or by induction of epigenetic marks de novo in each generation. To distinguish between these possibilities we measured epigenetic marks over four generations in rats exposed to a sustained environmental challenge. Dietary energy was increased by 25% at conception in F0 female rats and maintained at this level to generation F3. F0 dams showed higher pregnancy weight gain, but lower weight gain and food intake during lactation than F1 and F2 dams. On gestational day 8, fasting plasma glucose concentration was higher and β-hydroxybutyrate lower in F0 and F1 dams than F2 dams. This was accompanied by decreased phosphoenolpyruvate carboxykinase (PEPCK) and increased PPARα and carnitine palmitoyl transferase-1 mRNA expression. PEPCK mRNA expression was inversely related to the methylation of specific CpG dinucleotides in its promoter. DNA methyltransferase (Dnmt) 3a2, but not Dnmt1 or Dnmt3b, expression increased and methylation of its promoter decreased from F1 to F3 generations. These data suggest that the regulation of energy metabolism during pregnancy and lactation within a generation is influenced by the maternal phenotype in the preceding generation and the environment during the current pregnancy. The transgenerational effects on phenotype were associated with altered DNA methylation of specific genes in a manner consistent with induction de novo of epigenetic marks in each generation
Common Sense Recommendations for the Application of Tax Law to Digital Assets
In response to the Joint Committee on Taxation’s July 2023 request for comments on application of various Internal Revenue Code sections on digital assets, we propose a consistent set of rules to apply current law to digital assets. We highlight that the underlying economics and characteristics of transactions should be the primary concern for the application of rules and the valuation of digital assets. We believe any digital asset rules should (1) treat classes of digital assets with unique characteristics differently based on their economics, (2) minimize incentives for users to engage in tax-motivated structuring of transactions, and (3) allow the Internal Revenue Service authority to react to and regulate new classes of digital assets as they are created. We do not believe that the unique features of digital assets are a challenge to applying current law or warrant special tax preferred treatment
Improving the Quality and Utility of Electronic Health Record Data through Ontologies
The translational research community, in general, and the Clinical and Translational Science Awards (CTSA) community, in particular, share the vision of repurposing EHRs for research that will improve the quality of clinical practice. Many members of these communities are also aware that electronic health records (EHRs) suffer limitations of data becoming poorly structured, biased, and unusable out of original context. This creates obstacles to the continuity of care, utility, quality improvement, and translational research. Analogous limitations to sharing objective data in other areas of the natural sciences have been successfully overcome by developing and using common ontologies. This White Paper presents the authors’ rationale for the use of ontologies with computable semantics for the improvement of clinical data quality and EHR usability formulated for researchers with a stake in clinical and translational science and who are advocates for the use of information technology in medicine but at the same time are concerned by current major shortfalls. This White Paper outlines pitfalls, opportunities, and solutions and recommends increased investment in research and development of ontologies with computable semantics for a new generation of EHRs
Evolutionarily conserved and non-conserved retrovirus restriction activities of artiodactyl APOBEC3F proteins
The APOBEC3 proteins are unique to mammals. Many inhibit retrovirus infection through a cDNA cytosine deamination mechanism. HIV-1 neutralizes this host defense through Vif, which triggers APOBEC3 ubiquitination and degradation. Here, we report an APOBEC3F-like, double deaminase domain protein from three artiodactyls: cattle, pigs and sheep. Like their human counterparts, APOBEC3F and APOBEC3G, the artiodactyl APOBEC3F proteins are DNA cytosine deaminases that locate predominantly to the cytosol and can inhibit the replication of HIV-1 and MLV. Retrovirus restriction is attributable to deaminase-dependent and -independent mechanisms, as deaminase-defective mutants retain significant anti-retroviral activity. However, unlike human APOBEC3F and APOBEC3G, the artiodactyl APOBEC3F proteins have an active N-terminal DNA cytosine deaminase domain, which elicits a broader dinucleotide deamination preference, and they are resistant to HIV-1 Vif. These data indicate that DNA cytosine deamination; sub-cellular localization and retrovirus restriction activities are conserved in mammals, whereas active site location, local mutational preferences and Vif susceptibility are not. Together, these studies indicate that some properties of the mammal-specific, APOBEC3-dependent retroelement restriction system are necessary and conserved, but others are simultaneously modular and highly adaptable
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