•A new type of precast concrete beam-to-column connection was introduced.•All specimens showed flexural mode of failure with forming plastic hinge at beams.•The joints showed good seismic performance ...verified with ACI test procedure.•Joint cracks were controlled by using ECC as casting material.•Test specimens with outer type connection showed higher strength than inner type.
Five half-scale interior beam-column assemblies representing a portion of a frame subjected to simulated seismic loading were tested, including one monolithic specimen and four precast specimens. Variables included the detailing used at the joint to achieve a structural continuity of the beam reinforcement, and the type of special reinforcement in the connection (whether ECC or transverse reinforcement). The specimen design followed the strong-column-weak-beam concept.
The beam reinforcement was purposely designed and detailed to develop plastic hinges at the beam and to impose large inelastic shear force demands into the joint. The joint performance was evaluated on the basis of connection strength, stiffness, energy dissipation, and drift capacity. From the test results, the plastic hinges at the beam controlled the specimen failure. In general, the performance of the beam-to-column connections was satisfactory. The joint strength was 1.15 times of that expected for monolithic reinforced concrete construction. The specimen behavior was ductile due to tensile deformability by ECC and the yielding steel plate, while the strength was nearly constant up to a drift of 3.5%.
The fractionalization of elementary excitations in quantum spin systems is a central theme in current condensed matter physics. The Kitaev honeycomb spin model provides a prominent example of exotic ...fractionalized quasiparticles, composed of itinerant Majorana fermions and gapped gauge fluxes. However, identification of the Majorana fermions in a three-dimensional honeycomb lattice remains elusive. Here we report spectroscopic signatures of fractional excitations in the harmonic-honeycomb iridates β- and γ-Li2IrO3. Using polarization-resolved Raman spectroscopy, we find that the dynamical Raman response of β- and γ-Li2IrO3 features a broad scattering continuum with distinct polarization and composition dependence. The temperature dependence of the Raman spectral weight is dominated by the thermal damping of fermionic excitations. These results suggest the emergence of Majorana fermions from spin fractionalization in a three-dimensional Kitaev-Heisenberg system.
Kondo screening in a Majorana metal Lee, S.; Choi, Y. S.; Do, S.-H. ...
Nature communications,
11/2023, Letnik:
14, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
Kondo impurities provide a nontrivial probe to unravel the character of the excitations of a quantum spin liquid. In the
S
= 1/2 Kitaev model on the honeycomb lattice, Kondo impurities ...embedded in the spin-liquid host can be screened by itinerant Majorana fermions via gauge-flux binding. Here, we report experimental signatures of metallic-like Kondo screening at intermediate temperatures in the Kitaev honeycomb material
α
-RuCl
3
with dilute Cr
3+
(
S
= 3/2) impurities. The static magnetic susceptibility, the muon Knight shift, and the muon spin-relaxation rate all feature logarithmic divergences, a hallmark of a metallic Kondo effect. Concurrently, the linear coefficient of the magnetic specific heat is large in the same temperature regime, indicating the presence of a host Majorana metal. This observation opens new avenues for exploring uncharted Kondo physics in insulating quantum magnets.
Background and purpose
High blood pressure (BP) at presentation is associated with poor outcomes in acute ischaemic stroke, but serial BP measurements may better delineate the clinical implications ...of BP. The aim was to investigate the association between various BP parameters and functional outcomes in acute ischaemic stroke patients treated with endovascular thrombectomy (EVT).
Methods
This study reports a retrospective analysis of a prospective registry of a comprehensive stroke centre. Patients treated with EVT due to large vessel occlusion in the anterior circulation were enrolled. BP was measured hourly during the first 24 h after admission. Associations of various BP parameters, including BP variability, with functional outcomes at 3 months, including good outcomes (modified Rankin Scale score of 0–2), were analysed.
Results
Of the 378 enrolled patients (mean age 70 ± 11 years, male 54.2%), 313 (82.8%) achieved successful reperfusion after EVT, and 149 (39.4%) had good outcomes at 3 months. Higher mean systolic BP each 10 mmHg increase, odds ratio 0.82 (0.69–0.97) and higher systolic successive variation (SV) each 10% increase, odds ratio 0.37 (0.18–0.76) were associated with a reduced likelihood of achieving good outcomes. In addition, reperfusion status after EVT moderated the influence of higher systolic SV on good outcomes (Pint = 0.05).
Conclusion
The results showed that a higher mean systolic BP and systolic SV during the first 24 h of EVT reduced the likelihood of good outcomes at 3 months. The effects of these parameters on outcomes are more substantial amongst patients with successful reperfusion after EVT, suggesting that different BP control strategies should be employed according to reperfusion status.
Click here to view the accompanying paper in this volume.
Objective
To estimate the current prevalence rates and decadal trends of gout and hyperuricemia in the US, as well as the prevalence of urate‐lowering therapy (ULT) among gout patients, using ...2007–2016 data from a nationally representative survey of American men and women (the National Health and Nutrition Examination Survey NHANES).
Methods
Using data from 5,467 participants in the NHANES 2015–2016, we estimated the most recent prevalence rates of gout and hyperuricemia. When the NHANES was conducted, all participants were asked about their history of gout (as diagnosed by a health professional) and medication use. Hyperuricemia was defined as having a serum urate level of >7.0 mg/dl in men and >5.7 mg/dl in women. We examined decadal trends in these estimates using data from the NHANES 2007–2016 and investigated ULT usage trends using the NHANES 2007–14 (the most recent data available to date).
Results
In 2015–2016, the prevalence of gout was 3.9% among adults in the US (9.2 million people), with 5.2% 5.9 million in men and 2.7% 3.3 million in women. Mean serum urate levels were 6.0 mg/dl in men and 4.8 mg/dl in women, and hyperuricemia prevalence rates were 20.2% and 20.0%, respectively. The prevalence rates of gout and hyperuricemia remained stable between 2007 and 2016 (P for trend > 0.05). The prevalence of ULT use among patients with gout was 33% in 2007–2014 and remained stable over time (P for trend > 0.05).
Conclusion
In this nationally representative survey sample of adults in the US, the prevalence rates of gout and hyperuricemia remained substantial, albeit unchanged, between 2007 and 2016. Despite these rates, only one‐third of gout patients were receiving ULT.
Although endoscopic submucosal dissection (ESD) is increasingly utilized to treat early neoplasms of the gastrointestinal tract, its use for duodenal neoplasms is limited by the thin wall and narrow ...lumen of the duodenum. We have reviewed cases where ESD was used to treat sessile, nonampullary duodenal neoplasms. To do this, we retrospectively reviewed the medical records of patients treated with ESD for adenomas of the duodenum from January 2001 to December 2010, assessing the curative outcomes and complication rates. A total of 14 cases were reviewed. Mean patient age was 56.4 years. The mean size of tumors and mean size of the specimens were 17.1 mm and 26.4 mm, respectively. The en bloc resection rate with ESD was 78.6%, and the complete (R0) resection rate was 85.7%. No patient in the study experienced major bleeding. However, second-look endoscopy revealed minor bleeding requiring endoscopic homeostasis in one case (7.1%). Perforations were observed in five cases (35.7%). Two of the five patients with perforation underwent surgery. The ESD methods yielded acceptable curative resection rates for duodenal adenomas, although ESD was associated with a higher rate of perforation. Therefore, duodenal ESD should be performed with care and only in selected patients to avoid serious complications.
Aims
The purpose of this study was to isolate, identify and characterize an antifungal compound from Lactobacillus plantarum KCC‐10 from forage silage with potential beneficial properties.
Methods ...and Results
The 16S rRNA gene‐based phylogenetic affiliation was determined using bioinformatic tools and identified as Lactobacillus sp. KCC‐10 with 100% sequence similarity to L. plantarum. The antifungal substances were extracted with ethyl acetate from spent medium in which Lactobacillus sp. KCC‐10 was cultivated. Antifungal activity was assessed using the broth microdilution technique. The compounds were obtained by eluting the crude extract with various concentrations of solvents followed by chromatographic purification. Based on the infrared, 13C nuclear magnetic resonance (NMR) and 1H NMR spectral data, the compound was identified as a phenolic‐related antibiotic. The minimum inhibitory concentration of the compound against Aspergillus clavatus, A. oryzae, Botrytis elliptica and Scytalidium vaccinii was 2·5 mg ml−1 and that against A. fumigatus, A. niger and S. fusca was 5·0 mg ml−1, respectively. In addition, Lactobacillus sp. KCC‐10 was highly sensitive towards oxgall (0·3%) but grew well in the presence of sodium taurocholate (0·3%). An antimicrobial susceptibility pattern was an intrinsic feature of this strain; thus, consumption does not represent a health risk to humans or animals.
Conclusion
Novel L. plantarum KCC‐10 with antifungal and potential probiotic properties was characterized for use in animal food.
Significance and Impact of the Study
This study revealed that L. plantarum KCC‐10 exhibited good antifungal activity similar to that of probiotic Lactobacillus strains.
Abstract Purpose The objective of this study was to estimate the latest prevalence of major comorbidities associated with gout and hyperuricemia in the US based on a recent, nationally representative ...sample of US men and women. Methods Using data from 5707 participants aged 20 years and older in the National Health and Nutrition Examination Survey 2007-2008, we calculated the national prevalence and population estimates of major comorbidities according to gout status and various hyperuricemia levels, compared with those without these conditions. Case definitions of gout and comorbidities were based on an affirmative answer to a question that asked whether a physician or a health professional had diagnosed the corresponding condition. Results Among these individuals with gout, 74% (6.1 million) had hypertension, 71% (5.5 million) had chronic kidney disease stage ≥2, 53% (4.3 million) were obese, 26% (2.1 million) had diabetes, 24% (2.0 million) had nephrolithiasis, 14% (1.2 million) had myocardial infarction, 11% (0.9 million) had heart failure, and 10% (0.9 million) had suffered a stroke. These proportions were substantially higher than those among individuals without gout (all P -values <.67). With increasing levels of hyperuricemia, there were graded increases in the prevalences of these comorbidities. In the top category (serum urate ≥10 mg/dL), 86% of subjects had chronic kidney disease stage ≥2, 66% had hypertension, 65% were obese, 33% had heart failure, 33% had diabetes, 23% had myocardial infarction, and 12% had stroke. These prevalences were 3-33 times higher than those in the lowest serum urate category (<4 mg/dL). Sex-specific odds ratios tended to be larger among women than men, and the overall comorbidity prevalence was highest among individuals with both gout and hyperuricemia. Conclusions These findings from the latest nationally representative data highlight remarkable prevalences and population estimates of comorbidities of gout and hyperuricemia in the US. Appropriate preventive and management measures of these comorbidities should be implemented in gout management, with a preference to strategies that can improve gout and comorbidities together.
This paper studies reliability-based design optimization (RBDO) of a 5-MW wind turbine blade for designing reliable as well as economical wind turbine blades. A novel dynamic wind load uncertainty ...model has been developed using 249 groups of wind data to consider wind load variation over a large spatiotemporal range. The probability of fatigue failure during a 20-year service life is estimated using the uncertainty model in the RBDO process and is reduced to meet a desired target reliability. Meanwhile, the cost of composite materials used in the blade is minimized by optimizing the composite laminate thicknesses of the blade. In order to obtain the RBDO optimum design efficiently, deterministic design optimization (DDO) of the 5-MW wind turbine blade is carried out first using the mean wind load obtained from the wind load uncertainty model. The RBDO is then initiated from the DDO optimum. During the RBDO iterations, fatigue hotspots for RBDO are identified among the laminate section points. For an efficient RBDO process, surrogate models of 10-min fatigue damages
D
10
at the hotspots are accurately created using the Kriging method. Using the wind load uncertainty model and surrogate models, probability of fatigue failure during a 20-year lifespan at the hotspots and the design sensitivities are calculated at given design points. Using the probability of fatigue failure and design sensitivity, RBDO of the 5-MW wind turbine blade has been successfully carried out, satisfying the target probability of failure of 2.275 %.
Material pitting from cavitation bubble collapse is investigated numerically including two-way fluid–structure interaction (FSI). A hybrid numerical approach which links an incompressible boundary ...element method (BEM) solver and a compressible finite difference flow solver is applied to capture non-spherical bubble dynamics efficiently and accurately. The flow codes solve the fluid dynamics while intimately coupling the solution with a finite element structure code to enable simulation of the full FSI. During bubble collapse high impulsive pressures result from the impact of the bubble re-entrant jet on the material surface and from the collapse of the remaining bubble ring. A pit forms on the material surface when the impulsive pressure is large enough to result in high equivalent stresses exceeding the material yield stress. The results depend on bubble dynamics parameters such as the size of the bubble at its maximum volume, the bubble standoff distance from the material wall, and the pressure driving the bubble collapse. The effects of these parameters on the re-entrant jet, the following bubble ring collapse pressure, and the generated material pit characteristics are investigated.
PDF
