279 research outputs found
Models with short and long-range interactions: phase diagram and reentrant phase
We study the phase diagram of two different Hamiltonians with competiting
local, nearest-neighbour, and mean-field couplings. The first example
corresponds to the HMF Hamiltonian with an additional short-range interaction.
The second example is a reduced Hamiltonian for dipolar layered spin
structures, with a new feature with respect to the first example, the presence
of anisotropies. The two examples are solved in both the canonical and the
microcanonical ensemble using a combination of the min-max method with the
transfer operator method. The phase diagrams present typical features of
systems with long-range interactions: ensemble inequivalence, negative specific
heat and temperature jumps. Moreover, in a given range of parameters, we report
the signature of phase reentrance. This can also be interpreted as the presence
of azeotropy with the creation of two first order phase transitions with
ensemble inequivalence, as one parameter is varied continuously
Randomized Comparison of a CrossBoss First Versus Standard Wire Escalation Strategy for Crossing Coronary Chronic Total Occlusions: The CrossBoss First Trial
OBJECTIVES: The authors performed a multicenter, randomized-controlled, clinical trial comparing upfront use of the CrossBoss catheter versus antegrade wire escalation for antegrade crossing of coronary chronic total occlusions. BACKGROUND: There is equipoise about the optimal initial strategy for crossing coronary chronic total occlusions. METHODS: The primary endpoints were the time required to cross the chronic total occlusion or abort the procedure and the frequency of procedural major adverse cardiovascular events. The secondary endpoints were technical and procedural success, total procedure time, fluoroscopy time required to cross and total fluoroscopy time, total air kerma radiation dose, total contrast volume, and equipment use. RESULTS: Between 2015 and 2017, 246 patients were randomized to the CrossBoss catheter (n = 122) or wire escalation (n = 124) at 11 U.S. centers. The baseline clinical and angiographic characteristics of the study groups were similar. Technical and procedural success were 87.8% and 84.1%, respectively, and were similar in the 2 groups. Crossing time was similar: 56 min (interquartile range: 33 to 93 min) in the CrossBoss group and 66 min (interquartile range: 36 to 105 min) in the wire escalation group (p = 0.323), as was as the incidence of procedural major adverse cardiovascular events (3.28% vs. 4.03%; p = 1.000). There were no significant differences in the secondary study endpoints. CONCLUSIONS: As compared with wire escalation, upfront use of the CrossBoss catheter for antegrade crossing of coronary chronic total occlusions was associated with similar crossing time, similar success and complication rates, and similar equipment use and cost
A Genome-Wide Metabolic QTL Analysis in Europeans Implicates Two Loci Shaped by Recent Positive Selection
We have performed a metabolite quantitative trait locus (mQTL) study of the 1H nuclear magnetic resonance spectroscopy (1H NMR) metabolome in humans, building on recent targeted knowledge of genetic drivers of metabolic regulation. Urine and plasma samples were collected from two cohorts of individuals of European descent, with one cohort comprised of female twins donating samples longitudinally. Sample metabolite concentrations were quantified by 1H NMR and tested for association with genome-wide single-nucleotide polymorphisms (SNPs). Four metabolites' concentrations exhibited significant, replicable association with SNP variation (8.6×10−11<p<2.8×10−23). Three of these—trimethylamine, 3-amino-isobutyrate, and an N-acetylated compound—were measured in urine. The other—dimethylamine—was measured in plasma. Trimethylamine and dimethylamine mapped to a single genetic region (hence we report a total of three implicated genomic regions). Two of the three hit regions lie within haplotype blocks (at 2p13.1 and 10q24.2) that carry the genetic signature of strong, recent, positive selection in European populations. Genes NAT8 and PYROXD2, both with relatively uncharacterized functional roles, are good candidates for mediating the corresponding mQTL associations. The study's longitudinal twin design allowed detailed variance-components analysis of the sources of population variation in metabolite levels. The mQTLs explained 40%–64% of biological population variation in the corresponding metabolites' concentrations. These effect sizes are stronger than those reported in a recent, targeted mQTL study of metabolites in serum using the targeted-metabolomics Biocrates platform. By re-analysing our plasma samples using the Biocrates platform, we replicated the mQTL findings of the previous study and discovered a previously uncharacterized yet substantial familial component of variation in metabolite levels in addition to the heritability contribution from the corresponding mQTL effects
A Genome-Wide Metabolic QTL Analysis in Europeans Implicates Two Loci Shaped by Recent Positive Selection
We have performed a metabolite quantitative trait locus (mQTL) study of the 1H nuclear magnetic resonance spectroscopy (1H NMR) metabolome in humans, building on recent targeted knowledge of genetic drivers of metabolic regulation. Urine and plasma samples were collected from two cohorts of individuals of European descent, with one cohort comprised of female twins donating samples longitudinally. Sample metabolite concentrations were quantified by 1H NMR and tested for association with genome-wide single-nucleotide polymorphisms (SNPs). Four metabolites' concentrations exhibited significant, replicable association with SNP variation (8.6×10−11<p<2.8×10−23). Three of these—trimethylamine, 3-amino-isobutyrate, and an N-acetylated compound—were measured in urine. The other—dimethylamine—was measured in plasma. Trimethylamine and dimethylamine mapped to a single genetic region (hence we report a total of three implicated genomic regions). Two of the three hit regions lie within haplotype blocks (at 2p13.1 and 10q24.2) that carry the genetic signature of strong, recent, positive selection in European populations. Genes NAT8 and PYROXD2, both with relatively uncharacterized functional roles, are good candidates for mediating the corresponding mQTL associations. The study's longitudinal twin design allowed detailed variance-components analysis of the sources of population variation in metabolite levels. The mQTLs explained 40%–64% of biological population variation in the corresponding metabolites' concentrations. These effect sizes are stronger than those reported in a recent, targeted mQTL study of metabolites in serum using the targeted-metabolomics Biocrates platform. By re-analysing our plasma samples using the Biocrates platform, we replicated the mQTL findings of the previous study and discovered a previously uncharacterized yet substantial familial component of variation in metabolite levels in addition to the heritability contribution from the corresponding mQTL effects
Comparison of two different models for pile thermal response test interpretation
Thermal response tests (TRTs) are regularly used to characterise the thermal resistance of borehole heat exchangers and to assess the thermal conductivity of the surrounding ground. It is becoming common to apply the same in situ testing technique to pile heat exchangers, despite international guidance suggesting that TRTs should be limited to hole diameters of 152 mm (6 in.). This size restriction arises from the increased thermal inertia of larger diameter heat exchangers, which invalidates the assumption of a steady state within the concrete needed to interpret the test data by traditional line source analysis techniques. However, new methods of analysis for pile heat exchangers have recently been developed that take account of the transient behaviour of the pile concrete. This paper applies these new methods to data from a multi-stage TRT conducted on a small diameter test pile. The thermal conductivity and thermal resistance determined using this method are then compared with those from traditional analytical approaches based on a line source analysis. Differences between the approaches are discussed, along with the observation that the thermal resistance may not be constant over the different test stages
Idiopathic interstitial pneumonia: Do community and academic physicians agree on diagnosis?
Rationale: Treatment and prognoses of diffuse parenchymal lung
diseases (DPLDs) varies by diagnosis. Obtaining a uniform diagnosis
among observers is difficult.
Objectives: Evaluate diagnostic agreement between academic and
community-based physicians for patients with DPLDs, and determine
if an interactive approach between clinicians, radiologists,
and pathologists improved diagnostic agreement in community
and academic centers.
Methods: Retrospective review of 39 patients with DPLD. A total of
19 participants reviewed cases at 2 community locations and 1
academic location. Information from the history, physical examination,
pulmonary function testing, high-resolution computed tomography,
and surgical lung biopsy was collected. Data were presented
in the same sequential fashion to three groups of physicians on
separate days.
Measurements and Main Results: Each observer’s diagnosis was coded
into one of eight categories. A statistic allowing formultiple raters
was used to assess agreement in diagnosis. Interactions between
clinicians, radiologists, and pathologists improved interobserver
agreement at both community and academic sites; however, final
agreement was better within academic centers (Kappa= 0.55–0.71) than
within community centers (Kappa=0.32–0.44). Clinically significant
disagreement was present between academic and communitybased
physicians (Kappa=0.11–0.56). Community physicians were more
likely to assign a final diagnosis of idiopathic pulmonary fibrosis
compared with academic physicians.
Conclusions: Significant disagreement exists in the diagnosis of
DPLD between physicians based in communities compared with
those in academic centers. Wherever possible, patients should be
referred to centers with expertise in diffuse parenchymal lung disorders
to help clarify the diagnosis and provide suggestions regarding
treatment options.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91941/1/2007 AJRCCM Idiopathic interstitial pneumonia - Do community and academic physicians agree on diagnosis.pd
Altered Metabolism of Growth Hormone Receptor Mutant Mice: A Combined NMR Metabonomics and Microarray Study
Growth hormone is an important regulator of post-natal growth and metabolism. We have investigated the metabolic consequences of altered growth hormone signaling in mutant mice that have truncations at position 569 and 391 of the intracellular domain of the growth hormone receptor, and thus exhibit either low (around 30% maximum) or no growth hormone-dependent STATS signaling respectively. These mutants result in altered liver metabolism, obesity and insulin resistance
PCSK6 and Survival in Idiopathic Pulmonary Fibrosis
Rationale: Idiopathic pulmonary fibrosis (IPF) is a devastating disease characterized by limited treatment options and high mortality. A better understanding of the molecular drivers of IPF progression is needed. Objectives: To identify and validate molecular determinants of IPF survival. Methods: A staged genome-wide association study was performed using paired genomic and survival data. Stage I cases were drawn from centers across the United States and Europe and stage II cases from Vanderbilt University. Cox proportional hazards regression was used to identify gene variants associated with differential transplantation-free survival (TFS). Stage I variants with nominal significance (P < 5 x 10(-5)) were advanced for stage II testing and meta-analyzed to identify those reaching genome-wide significance (P < 5 x 10(-8)). Downstream analyses were performed for genes and proteins associated with variants reaching genome-wide significance. Measurements and Main Results: After quality controls, 1,481 stage I cases and 397 stage II cases were included in the analysis. After filtering, 9,075,629 variants were tested in stage I, with 158 meeting advancement criteria. Four variants associated with TFS with consistent effect direction were identified in stage II, including one in an intron of PCSK6 (proprotein convertase subtilisin/kexin type 6) reaching genome-wide significance (hazard ratio, 4.11 [95% confidence interval, 2.54-6.67]; P = 9.45 x 10(-9)). PCSK6 protein was highly expressed in IPF lung parenchyma. PCSK6 lung staining intensity, peripheral blood gene expression, and plasma concentration were associated with reduced TFS. Conclusions: We identified four novel variants associated with IPF survival, including one in PCSK6 that reached genome-wide significance. Downstream analyses suggested that PCSK6 protein plays a potentially important role in IPF progression
Introduction
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67161/2/10.1177_0308275X9301300401.pd
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