311 research outputs found
Cutoff dependence of the thrust peak position in the dipole shower
We analyse the dependence of the peak position of the thrust distribution on
the cutoff value in the Nagy-Soper dipole shower. We compare the outcome of the
parton shower simulations to a relation of the dependence from an analytic
computation, derived within soft-collinear effective theory. We show that the
result of the parton shower simulations and the analytic computation are in
good agreement.Comment: 13 pages, v2: version to be publishe
Real-space electronic-structure calculations with full-potential all-electron precision for transition-metals
We have developed an efficient computational scheme utilizing the real-space
finite-difference formalism and the projector augmented-wave (PAW) method to
perform precise first-principles electronic-structure simulations based on the
density functional theory for systems containing transition metals with a
modest computational effort. By combining the advantages of the time-saving
double-grid technique and the Fourier filtering procedure for the projectors of
pseudopotentials, we can overcome the egg box effect in the computations even
for first-row elements and transition metals, which is a problem of the
real-space finite-difference formalism. In order to demonstrate the potential
power in terms of precision and applicability of the present scheme, we have
carried out simulations to examine several bulk properties and structural
energy differences between different bulk phases of transition metals, and have
obtained excellent agreement with the results of other precise first-principles
methods such as a plane wave based PAW method and an all-electron
full-potential linearized augmented plane wave (FLAPW) method.Comment: 29 Page
Complex magnetism of B20-MnGe: from spin-spirals, hedgehogs to monopoles
B20 compounds are the playground for various non-trivial magnetic textures
such as skyrmions, which are topologically protected states. Recent
measurements on B20-MnGe indicate no clear consensus on its magnetic behavior,
which is characterized by the presence of either spin-spirals or 3-dimensional
objects interpreted to be a cubic lattice of hedgehogs and anti-hedgehogs.
Utilizing a massively parallel linear scaling all-electron density functional
algorithm, we find from full first-principles simulations on cells containing
thousands of atoms that upon increase of the compound volume, the state with
lowest energy switches across different magnetic phases: ferromagnetic,
spin-spiral, hedgehog and monopole
Understanding the consequences of educational inequalities on periodontitis: a Mendelian randomization study
A Mendelian randomization study on the effect of 25âhydroxyvitamin D levels on periodontitis
Abstract
Background
Twenty fiveâhydroxy vitamin D (25OHD) levels have been proposed to protect against periodontitis based on in vitro and observational studies but evidence from longâterm randomized controlled trials (RCTs) is lacking. This study tested whether genetically proxied 25OHD is associated with periodontitis using Mendelian randomization (MR).
Methods
Genetic variants strongly associated with 25OHD in a genomeâwide association study (GWAS) of 417,580 participants of European ancestry were used as instrumental variables, and linked to GWAS summary data of 17,353 periodontitis cases and 28,210 controls. In addition to the main analysis using an inverse variance weighted (IVW) model, we applied additional robust methods to control for pleiotropy. We also undertook sensitivity analyses excluding single nucleotide polymorphisms (SNPs) used as instruments with potential pleiotropic effects and used a second 25OHD GWAS for replication. We identified 288 SNPs to be genomeâwide significant for 25OHD, explaining 7.0% of the variance of 25OHD levels and providing â„90% power to detect an odds ratio (OR) of †0.97.
Results
MR analysis suggested that a 1 standard deviation increase in natural logâtransformed 25OHD was not associated with periodontitis risk (IVW OR = 1.04; 95% confidence interval (CI): 0.97â1.12; Pâvalue = 0.297). The robust models, replication, and sensitivity analyses were coherent with the primary analysis.
Conclusions
Collectively, our findings suggest that 25OHD levels are unlikely to have a substantial effect on the risk of periodontitis, but large longâterm RCTs are needed to derive definitive evidence on the causal role of 25OHD in periodontitis
KĂŒnstliche Intelligenz in der Hals-Nasen-Ohren-Heilkunde
BACKGROUND The continued advancement of digitalization increasingly allows deployment of artificial intelligence (AI) algorithms, leveraging profound effects on society and medicine. OBJECTIVE This article aims to provide an overview of current developments and futures perspectives of AI in otorhinolaryngology. MATERIALS AND METHODS Scientific studies and expert analyses were evaluated and discussed. RESULTS AI can increase the value of current diagnostic tools in otorhinolaryngology and enhance surgical precision in head and neck surgery. CONCLUSION AI has the potential to further improve diagnostic and therapeutic procedures in otorhinolaryngology. This technology, however, is associated with challenges, for example in the domain of privacy and data security. ZUSAMMENFASSUNG HINTERGRUND: Die fortschreitende Digitalisierung ermöglicht zunehmend den Einsatz von kĂŒnstlicher Intelligenz (KI). Sie wird Gesellschaft und Medizin in den nĂ€chsten Jahren maĂgeblich beeinflussen. ZIEL DER ARBEIT Darstellung des gegenwĂ€rtigen Einsatzspektrums von KI in der Hals-Nasen-Ohren-Heilkunde und Skizzierung zukĂŒnftiger Entwicklungen bei der Anwendung dieser Technologie. MATERIAL UND METHODEN Es erfolgte die Auswertung und Diskussion wissenschaftlicher Studien und Expertenanalysen. ERGEBNISSE Durch die Verwendung von KI kann der Nutzen herkömmlicher diagnostischer Werkzeuge in der Hals-Nasen-Ohren-Heilkunde gesteigert werden. Zudem kann der Einsatz dieser Technologie die chirurgische PrĂ€zision in der Kopf-Hals-Chirurgie weiter erhöhen. SCHLUSSFOLGERUNGEN KI besitzt ein groĂes Potenzial zur weiteren Verbesserung diagnostischer und therapeutischer Verfahren in der Hals-Nasen-Ohren-Heilkunde. Allerdings ist die Anwendung dieser Technologie auch mit Herausforderungen verbunden, beispielsweise im Bereich des Datenschutzes
Exploring real-time functional magnetic resonance imaging neurofeedback in adolescents with disruptive behavior disorder and callous unemotional traits
Introduction: Adolescents with increased callous unemotional traits (CU traits) in the context of disruptive behavior disorder (DBD) show a persistent pattern of antisocial behavior with shallow affect and a lack of empathy or remorse. The amygdala and insula as regions commonly associated with emotion processing, empathy and arousal are implicated in DBD with high CU traits. While behavioral therapies for DBD provide significant but small effects, individualized treatments targeting the implicated brain regions are missing.
Methods: In this explorative randomized controlled trial we randomly assigned twenty-seven adolescents with DBD to individualized real-time functional magnetic resonance neurofeedback (rtfMRI-NF) or behavioral treatment as usual (TAU). Visual feedback of either amygdala or insula activity was provided during rtfMRI-NF by gauges and included a simple and concurrent video run plus a transfer run. A linear mixed model (LMM) was applied to determine improvement of self-regulation. Specificity was assessed by correlating individual self-regulation improvement with clinical outcomes.
Results: The rtfMRI-NF (n = 11) and TAU (n = 10) completers showed comparable and significant clinical improvement indicating neither superiority nor inferiority of rtfMRI-NF. The exploratory LMM revealed successful learning of self-regulation along the course of training for participants who received feedback from the amygdala. A significant exploratory correlation between individual target region activity in the simple run and clinical improvement was found for one dimension of DBD.
Conclusions: This exploratory study demonstrated feasibility and suggests clinical efficacy of individualized rtfMRI-NF comparable to active TAU for adolescents with DBD and increased CU traits. Further studies are needed to confirm efficacy, specificity and to clarify underlying learning mechanisms
Relevance of Lysine Snorkeling in the Outer Transmembrane Domain of Small Viral Potassium Ion Channels
Transmembrane domains (TMDs) are often flanked by Lys or Arg because they keep their aliphatic parts in the bilayer and their charged groups in the polar interface. Here we examine the relevance of this so-called âsnorkelingâ of a cationic amino acid, which is conserved in the outer TMD of small viral K+ channels. Experimentally, snorkeling activity is not mandatory for KcvPBCV-1 because K29 can be replaced by most of the natural amino acids without any corruption of function. Two similar channels, KcvATCV-1 and KcvMT325, lack a cytosolic N-terminus, and neutralization of their equivalent cationic amino acids inhibits their function. To understand the variable importance of the cationic amino acids, we reanalyzed molecular dynamics simulations of KcvPBCV-1 and N-terminally truncated mutants; the truncated mutants mimic KcvATCV-1 and KcvMT325. Structures were analyzed with respect to membrane positioning in relation to the orientation of K29. The results indicate that the architecture of the protein (including the selectivity filter) is only weakly dependent on TMD length and protonation of K29. The penetration depth of Lys in a given protonation state is independent of the TMD architecture, which leads to a distortion of shorter proteins. The data imply that snorkeling can be important for K+ channels; however, its significance depends on the architecture of the entire TMD. The observation that the most severe N-terminal truncation causes the outer TMD to move toward the cytosolic side suggests that snorkeling becomes more relevant if TMDs are not stabilized in the membrane by other domains
Relevance of Lysine Snorkeling in the Outer Transmembrane Domain of Small Viral Potassium Ion Channels
Transmembrane domains (TMDs) are often flanked by Lys or Arg because they keep their aliphatic parts in the bilayer and their charged groups in the polar interface. Here we examine the relevance of this so-called âsnorkelingâ of a cationic amino acid, which is conserved in the outer TMD of small viral K+ channels. Experimentally, snorkeling activity is not mandatory for KcvPBCV-1 because K29 can be replaced by most of the natural amino acids without any corruption of function. Two similar channels, KcvATCV-1 and KcvMT325, lack a cytosolic N-terminus, and neutralization of their equivalent cationic amino acids inhibits their function. To understand the variable importance of the cationic amino acids, we reanalyzed molecular dynamics simulations of KcvPBCV-1 and N-terminally truncated mutants; the truncated mutants mimic KcvATCV-1 and KcvMT325. Structures were analyzed with respect to membrane positioning in relation to the orientation of K29. The results indicate that the architecture of the protein (including the selectivity filter) is only weakly dependent on TMD length and protonation of K29. The penetration depth of Lys in a given protonation state is independent of the TMD architecture, which leads to a distortion of shorter proteins. The data imply that snorkeling can be important for K+ channels; however, its significance depends on the architecture of the entire TMD. The observation that the most severe N-terminal truncation causes the outer TMD to move toward the cytosolic side suggests that snorkeling becomes more relevant if TMDs are not stabilized in the membrane by other domains
Dissecting the molecular organization of the translocon-associated protein complex
In eukaryotic cells, one-third of all proteins must be transported across or inserted into the endoplasmic reticulum (ER) membrane by the ER protein translocon. The translocon-associated protein (TRAP) complex is an integral component of the translocon, assisting the Sec61 protein-conducting channel by regulating signal sequence and transmembrane helix insertion in a substrate-dependent manner. Here we use cryo-electron tomography (CET) to study the structure of the native translocon in evolutionarily divergent organisms and disease-linked TRAP mutant fibroblasts from human patients. The structural differences detected by subtomogram analysis form a basis for dissecting the molecular organization of the TRAP complex. We assign positions to the four TRAP subunits within the complex, providing insights into their individual functions. The revealed molecular architecture of a central translocon component advances our understanding of membrane protein biogenesis and sheds light on the role of TRAP in human congenital disorders of glycosylation
- âŠ