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The crack phase field model has been well established and validated for a variety of complex crack propagation patterns within a homogeneous medium under either tensile or shear ...loading. However, relatively less attention has been paid to crack propagation under combined tensile and shear loading or crack propagation within composite materials made of two constituents with very different elastic moduli. In this work, we compare crack propagation under such circumstances modelled by two representative formulations, anisotropic and hybrid formulations, which have distinct stiffness degradation schemes upon crack propagation. We demonstrate that the hybrid formulation is more adequate for modeling crack propagation problems under combined loading because the residual stiffness of the damaged zone in the anisotropic formulation may lead to spurious crack growth and altered load–displacement response.
The Dzyaloshinskii-Moriya interaction (DMI), which only exists in noncentrosymmetric systems, plays an important role in the formation of exotic chiral magnetic states. However, the absence of the ...DMI occurs in most two-dimensional (2D) magnetic materials due to their intrinsic inversion symmetry. Here, by using first-principles calculations, we demonstrate that a significant DMI can be obtained in a series of Janus monolayers of dichalcogenides XSeTe (X = Nb, Re) in which the difference between Se and Te on the opposite sides of X breaks the inversion symmetry. Remarkably, the DMI amplitudes of NbSeTe (1.78 meV) and ReSeTe (4.82 meV) are larger than the experimental value of Co/graphene (0.16 meV), and NbSeTe and ReSeTe monolayers have a high Curie temperature of 1023 K and 689 K, respectively. Through the micromagnetic simulation of XSeTe (X= Nb, Re) simulations, we also find that the ReSeTe monolayer can performance for skyrmion states by applying an external magnetic field, and importantly, the skyrmion states can be regulated and controlled under external strain. The findings pave the way for device concepts using chiral magnetic structures in specially designed 2D ferromagnetic materials.
The DzyaloshinskiiMoriya interaction (DMI), which only exists in noncentrosymmetric systems, plays an important role in the formation of exotic chiral magnetic states.
•The characteristics and properties of lightweight aggregate concrete and foamed concrete with the same density levels were investigated based on image analysis.•SEM images confirmed that the solid ...structures of the matrix in foamed concrete are relatively denser than that of lightweight aggregate concrete.•The micro-CT images demonstrated that foamed concrete has larger porosity than lightweight aggregate concrete when the material density is similar.•The proper use of lightweight aggregate concrete can be more beneficial in terms of having a material with better mechanical performance by minimizing the loss of the insulation effect.
Lightweight concrete is a special type of concrete with low density and advanced insulation, mainly produced using lightweight aggregates or a cellular matrix. Concrete material made of lightweight aggregates is called lightweight aggregate concrete, while material made from a cellular matrix is generally called foamed concrete because of the pores introduced by a foaming agent. Both lightweight concrete types have different characteristics due to their different compositions. In this study, the material properties and characteristics of these lightweight concretes were investigated and compared. A series of foamed and lightweight aggregate concrete specimens with the same density level were produced, with their mechanical and thermal properties being evaluated using sensitive measurement tools. X-ray micro-computed tomography (μ-CT) and scanning electron microscopy (SEM) were used to characterize each material, using image-based techniques. The results brought to light the details of each lightweight concrete, at the microstructural level, in regard to their material properties and showed that the properly designed lightweight aggregate concrete can be more beneficial in mechanical performance by minimizing the loss of the insulation.
To determine the efficacy of acupuncture for hypertension.
Seven electronic databases were searched on April 13, 2014 to include eligible randomized controlled trials (RCTs). Data were extracted and ...risk of bias was assessed. Subgroup analyses and meta- analysis were performed.
23 RCTs involving 1788 patients were included. Most trials had an unclear risk of bias regarding allocation concealment, blinding, incomplete outcome data and selective reporting. Compared with sham acupuncture plus medication, a meta-analysis of 2 trials revealed that acupuncture as an adjunct to medication was more effective on systolic (SBP) and diastolic (DBP) blood pressure change magnitude (n=170, SBP: mean difference (MD)= -7.47,95% confidence intervals (CI):-10.43 to -4.51,I2 =0%; DBP: -4.22,-6.26 to -2.18, 0%).A subgroup analysis of 4 trials also showed acupuncture combined with medication was superior to medication on efficacy rate (n=230, odds ratio (OR)=4.19, 95%CI: 1.65 to 10.67, I2 =0%). By contrast, compared with medication, acupuncture alone showed no significant effect on SBP /DBP after intervention and efficacy rate in the subgroup analysis. (7 trials with 510 patients, SBP: MD=-0.56, 95%CI:-3.02 to 1.89,I2 =60%; DBP: -1.01,-2.26 to 0.24, 23%; efficacy rate: 10 trials with 963 patients, OR=1.14, 95% CI: 0.70 to 1.85, I2 =54%).Adverse events were inadequately reported in most RCTs.
Our review provided evidence of acupuncture as an adjunctive therapy to medication for treating hypertension, while the evidence for acupuncture alone lowing BP is insufficient. The safety of acupuncture is uncertain due to the inadequate reporting of it. However, the current evidence might not be sufficiently robust against methodological flaws and significant heterogeneity of the included RCTs. Larger high-quality trials are required.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Aversion to environmental cues of predators is an integral part of defensive behaviors in many prey animals. It enhances their survival and probability of future reproduction. At the same time, ...animals cannot be maximally defended because imperatives of defense usually trade-off with behaviors required for sexual reproduction like display of dominance and production of sexual pheromones. Here, we approach this trade-off through the lens of arginine vasopressin (AVP) neurons within the posterodorsal medial amygdala (MePD) of mice. This neuronal population is known to be involved in sexual behaviors like approach to sexually salient cues. We show that chemogenetic partial ablation of this neuronal population increases aversion to predator odors. Moreover, overexpression of AVP within this population is sufficient to reduce aversion to predator odors. The loss of fear of the predator odor occurs in parallel with increased recruitment of AVP neurons within the MePD. These observations suggest that AVP neurons in the medial aspect of the extended amygdala are a proximate locus for the reduction in innate fear during life stages dominated by reproductive efforts.
Background
Acute myocardial infarction (AMI) is a disease with high morbidity and mortality worldwide and the evaluation of myocardial injury and perfusion status following myocardial ischemia and ...reperfusion is of clinical value.
Purpose
To assess the diagnostic utility of simplified perfusion fraction (SPF) in differentiating salvage and infarcted myocardium and its predictive value for left ventricular remodeling in patients with reperfusion ST‐segment elevation myocardial infarction (STEMI).
Study Type
Prospective.
Population
Forty‐one reperfused STEMI patients and 20 healthy volunteers.
Field Strength/Sequence
3.0T MRI. The MR examination included cine, T2‐short tau inversion recovery (T2‐STIR), first pass perfusiong (FPP)，phase sensitive inversion recovery (PSIR), and diffusion‐weighted imaging (DWI).
Assessment
SPF values among different myocardium regions (infarcted, salvaged, remote, and MVO) and stages of reperfused STEMI patients as well as normal controls were measured. The diagnostic utility of SPF values in differentiating salvaged and infarcted myocardium was assessed.
Statistical Analysis
Independent t‐test and the Mann–Whitney U‐test. Logistic regression.
Results
SPF values in healthy controls were not significantly different than SPF values in the remote myocardium of patients (40.09 ± 1.47% vs. 40.28 ± 1.93%, P = 0.698). In reperfusion STEMI patients, SPF values were lower in infarcted myocardium compared to remote and salvaged myocardium (32.15 ± 2.36% vs. 40.28 ± 1.93%, P < 0.001; 32.15 ± 2.36% vs. 36.68 ± 2.71%, P < 0.001). SPF values of infarcted myocardium showed a rebound increase from acute to convalescent stages (32.15 ± 2.36% vs. 34.69 ± 3.69%, P < 0.001). When differentiating infarcted and salvaged myocardium, SPF values demonstrated an area under the curve (AUC) of 0.89 (sensitivity 85.4%, specificity 80.5%, cutoff 34.42%). Lower SPF values were associated with lower odds ratio (OR = 0.304) of left ventricular remodeling after adjusting for potential confounders with a confidence interval (CI) of 0.129–0.717, P = 0.007.
Data Conclusion
SPF might be able to differentiate salvaged and infarcted myocardium and is a strong predictor of left ventricular remodeling in reperfused STEMI patients.
Level of Evidence 2
Technical Efficacy Stage 2
Endomorphins have shown great promise as pharmaceutics for the treatment of pain. We have previously confirmed that novel endomorphin analogues CEMR-1 and CEMR-2 behaved as potent μ agonists and ...displayed potent antinociceptive activities at the supraspinal and peripheral levels. The present study was undertaken to evaluate the antinociceptive properties of CEMR-1 and CEMR-2 following intrathecal (i.t.) administration. Furthermore, their antinociceptive tolerance and opioid-like side effects were also determined.
The spinal antinociceptive effects of CEMR-1 and CEMR-2 were determined in a series of pain models, including acute radiant heat paw withdrawal test, spared nerve injury-induced neuropathic pain, complete Freund's adjuvant-induced inflammatory pain, visceral pain and formalin pain. Antinociceptive tolerance was evaluated in radiant heat paw withdrawal test.
Spinal administration of CEMR-1 and CEMR-2 produced potent and prolonged antinociceptive effects in acute pain. CEMR-1 and CEMR-2 may produce their antinociception through distinct μ receptor subtypes. These two analogues also exhibited significant analgesic activities in neuropathic, inflammatory, visceral and formalin pain at the spinal level. It is noteworthy that CEMR-1 showed non-tolerance-forming analgesic properties, while CEMR-2 exhibited substantially reduced antinociceptive tolerance. Furthermore, both analogues displayed no or reduced side effects on conditioned place preference response, physical dependence, locomotor activity and gastrointestinal transit.
The present investigation demonstrated that CEMR-1 and CEMR-2 displayed potent and long-lasting antinociception with a favourable side effect profile at the spinal level. Therefore, CEMR-1 and CEMR-2 might serve as promising analgesic compounds with minimal opioid-like side effects.
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•Kitchen waste biodrying used a compound stone amendment to partially replace sawdust.•Biomarker analysis and KEGG prediction highlight the role of the thermophilic ...phase.•Thermophilic phase inactivated pathogens, potentially improving nutrient metabolism.•After biodrying, microbial richness rebounded, including pathogenic microorganisms.•The new amendment improved biodrying so the product can be used as biofuel.
Biodrying in conjunction with compound stone amendment was used to treat kitchen waste, which improved biodrying. After 16 days, the pile moisture content decreased from 68.8% to 23.0%. Lignin, cellulose and hemicellulose concentrations decreased from 104.6 mg g−1 d.b., 322.9 mg g−1 d.b. and 155.9 mg g−1 d.b., respectively, to 74.0 mg g−1 d.b., 224.8 mg g−1 d.b. and 134.5 mg g−1 d.b., respectively. The Shannon index for bacteria increased from 2.5 to 3.1, while for fungi, it decreased from 4.6 to 0.6. The relative abundances of Amino Acid Metabolism and Carbohydrate Metabolism exceeded 7%. The thermophilic phase during the process inactivated the pathogenic microorganisms, increased the bacterial diversity, decreased the fungal diversity, and potentially improved the metabolism of nutrients, including amino acids, carbohydrates, lipids and vitamins. The biomarker analysis and predicated protein sequences provide genetic evidence to elucidate why the thermophilic phase is the peak time for nutrient metabolism.
Meta-heuristic algorithms have gained substantial popularity in recent decades and have focused on applications in a wide spectrum of fields. In this paper, a new and powerful physics-based algorithm ...named nuclear reaction optimization (NRO) is presented. Meanwhile, NRO imitates the nuclear reaction process and consists of two phases, namely, a nuclear fission (NFi) phase and a nuclear fusion (NFu) phase. The Gaussian walk and differential evolution operators between nucleus and neutron are employed for exploitation and appropriate exploration in the (NFi) phase, respectively. Meanwhile, the variants of differential evolution operator are utilized for exploration in the NFu phase, which consists of the ionization and fusion stages. Additionally, the variants of Levy flight are used for random searching to escape from the local optima in each stage of the NFu phase. The exploration and exploitation abilities of NRO can be balanced due to a combination of the two phases. Both constrained and unconstrained benchmark functions are employed for testing the performance of NRO. To make comparisons between NRO and the state-of-the-art algorithms, 23 classic benchmark functions and twenty-night modern benchmark functions are performed. Moreover, three engineering design optimization problems are solved as constrained benchmark functions by using NRO and the compared algorithms. The results illustrate that the proposed nuclear reaction optimization algorithm is a potential and powerful approach for global optimization.
•Issues on domain size and resolution of μ-CT images of cement paste are identified.•Phase separation procedure for μ-CT images of cement paste is extended.•Phase field fracture model performs ...adequately as a virtual loading tool.•Virtual experiment shows a potential to supplement real experiment of cement paste.
There are issues on the microstructure characterization of cement paste obtained from μ-CT due to resolution limits, and evaluation of properties through virtual experiments. A phase separation procedure between the solid and pore phases, which can be used for pure cement paste microstructures, is proposed. The problems of underestimation of microstructural characteristics such as porosity in virtual specimens from μ-CT, as compared to real specimens, are addressed. Reflecting such underestimation, the process of input modeling parameter determination for virtual experiments on mechanical property evaluation using the phase field fracture model is elaborated. Through virtual tests, the effects of domain size and mesh resolution on the evaluated properties are investigated, and the correlation between the microstructural characterization parameters and mechanical properties is reconfirmed. It is shown that the virtual experiment framework proposed in this study can be used as a loading tool to supplement time and effort consuming real experiments for evaluating the mechanical properties of cement paste at the micro-scale.
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