Estimation of biomass in various components of Pinus koraiensis based on Bayesian methods

IntroductionPinus koraiensis is a dominant tree species in northeastern China. Estimating its biomass is required for forest carbon stock monitoring and accounting.MethodsThis study investigates biomass estimation methods for P. koraiensis components. A Bayesian approach was used to synthesize the parameter distributions of 298 biomass models as prior information to estimate the trunk, branch, leaf, and root biomass of P. koraiensis. The results were compared with non-informative prior and the minimum least squares (MLS).ResultsThe results indicated that the Bayesian approach outperformed the other methods regarding model fit and prediction error. In addition, the responses of different components to tree height varied. The models of trunk and root biomass exhibited a smaller response to tree height, whereas those of branches and leaves showed a larger response to tree height. The model parameters yield precise estimations.DiscussionIn sum, this study highlights the potential of the Bayesian methods in estimating P. koraiensis biomass and proposes further enhancements to improve estimation accuracy

Isolation of a Ferroelectric Intermediate Phase in Antiferroelectric Dense Sodium Niobate Ceramics

Switchable ferroelectric/antiferroelectric ceramics are of significant interest for high power energy storage applications. Grain size control of this switching is an interesting approach to controlling polarization and hence dielectric properties. However, the use of this approach in technologically relevant ceramics is hindered by difficulty in fabricating dense ceramics with small grain sizes. Here an intermediate polar ferroelectric phase (P21ma) has been isolated in dense bulk sodium niobate ceramics by grain size control through spark plasma sintering methods. Our findings, supported by XRD, DSC, P-E (I-E) loops and dielectric characterization, provide evidence that the phase transition from the antiferroelectric (AFE) R-phase, in space group Pnmm, above 300 C, to the AFE P-phase, in space group Pbma, at room temperature, always involves the polar intermediate P21ma phase and that the P21ma to Pbma transition can be suppressed by reducing grain size

Terahertz Probing Irreversible Phase Transitions Related to Polar Clusters in Bi0.5Na0.5TiO3-based Ferroelectric

Electric-field-induced phase transitions in Bi0.5Na0.5TiO3 (BNT)-based relaxor ferroelectrics are essential to the controlling of their electrical properties and consequently in revolutionizing their dielectric and piezoelectric applications. However, the fundamental understanding of these transitions is a long-standing challenge due to their complex crystal structures. Given the structural inhomogeneity at the nanoscale or sub-nanoscale in these materials, dielectric response characterization based on terahertz (THz) electromagnetic-probe beam-fields, is intrinsically coordinated to lattice dynamics during DC-biased poling cycles. The complex permittivity reveals the field-induced phase transitions to be irreversible. This profoundly counters the claim of reversibility, the conventional support for which, is based upon the peak that is manifest in each of four quadrants of the current-field curves. The mechanism of this irreversibility is solely attributed to polar clusters in the transformed lattices. These represent an extrinsic factor which is quiescent in the THz spectral domain

Perovskite Srx(Bi1-xNa0.97-xLi0.03)0.5TiO3 ceramics with polar nano regions for high power energy storage

Dielectric capacitors are very attractive for high power energy storage. However, the low energy density of these capacitors, which is mainly limited by the dielectric materials, is still the bottleneck for their applications. In this work, lead-free single-phase perovskite Srx(Bi1-xNa0.97-xLi0.03)0.5TiO3 (x=0.30 and 0.38) bulk ceramics, prepared using solid-state reaction method, were carefully studied for the dielectric capacitor application. Polar nano regions (PNRs) were created in this material using co-substitution at A-site to enable relaxor behaviour with low remnant polarization (Pr) and high maximum polarization (Pmax). Moreover, Pmax was further increased due to reversible electric field induced phase transitions. Comprehensive structural and electrical studies were performed to confirm the PNRs and the reversible phase transitions. And finally a high energy density (1.70 J/cm3) with an excellent efficiency (87.2%) was achieved using the contribution of PNRs and field-induced transitions in this material, making it among the best performing lead-free dielectric ceramic bulk material for high energy storage

Crystal structure and electrical properties of textured Ba2Bi4Ti5O18 ceramics

Highly textured Ba2Bi4Ti5O18 ceramic was prepared by spark plasma sintering (SPS). X-ray diffraction of the ceramics revealed the coexistence of a major ferroelectric phase (Space group, SG: B2cb) and a minor paraelectric phase (SG: I4/mmm) at room temperature. A diffused phase transition was observed at around 240 °C. The evolution of the switching current peaks in the electric current vs. electric field (I-E) loops with increasing temperature was interpreted by the structural changes and temperature dependent polarisation reversal processes. The slim polarisation vs. electric field (P-E) loops, the extra switching current peaks in the I-E loops and the non-zero piezoelectric d33 coefficient indicate that Ba2Bi4Ti5O18 is a relaxor ferroelectric material. The recoverable energy density (0.41 ± 0.01 J/cm3) of Ba2Bi4Ti5O18 ceramics in the perpendicular direction to the SPS pressing direction is close to that of Pb(Mg1/3Nb2/3)O3-based ceramics. The obtained results suggest Ba2Bi4Ti5O18 ceramics might be promising for energy storage applications

Microwave characterization of two Ba0.6Sr0.4TiO3 dielectric thin films with out-of-plane and in-plane electrode structures

Ferroelectric (FE) thin films have recently attracted renewed interest in research due to their great potential for designing novel tunable electromagnetic devices such as large intelligent surfaces (LISs). However, the mechanism of how a polar structure in the FE thin films contributes to desired tunable performance, especially within the microwave frequency range, which is the most widely used frequency range of electromagnetics, has not been illustrated clearly. In this paper, we described several straightforward and cost-effective methods to fabricate and characterize Ba0.6 Sr0.4 TiO3 (BST) thin films at microwave frequencies. The prepared BST thin films here exhibit homogenous structures and great tunability (h) in a wide frequency and temperature range when the applied field is in the out-of-plane direction. The high tunability can be attributed to high concentration of polar nanoclusters. Their response to the applied direct current (DC) field was directly visualized using a novel non-destructive near-field scanning microwave microscopy (NSMM) technique. Our results have provided some intriguing insights into the application of the FE thin films for future programmable high-frequency devices and systems

Total Cerebral Small Vessel Disease Score and Cerebral Bleeding Risk in Patients With Acute Stroke Treated With Intravenous Thrombolysis

OBJECTIVE: The aim of this study was to investigate the association of total cerebral small vessel disease (cSVD) score with the risk of intracerebral hemorrhage (ICH) in patients with acute ischemic stroke who received intravenous thrombolysis (IVT) using recombinant tissue-plasminogen activator (rt-PA). METHODS: We retrospectively reviewed clinical data from two stroke registries of patients with acute ischemic stroke treated with IVT. We assessed the baseline magnetic resonance (MR) visible cSVD markers and total cSVD score (ranging from 0 to 4) between patients with and without ICH after IVT. Logistic regression analysis was used to determine the association of total cSVD score with the risk of ICH after IVT, adjusted for cofounders selected by least absolute shrinkage and selection operator (LASSO). We additionally performed an E-value analysis to fully explain away a specific exposure-outcome association. Receiver operating characteristic (ROC) curve analysis was used to quantify the predictive potential of the total cSVD score for any ICH after IVT. RESULTS: Among 271 eligible patients, 55 (20.3%) patients experienced any ICH, 16 (5.9%) patients experienced a symptomatic ICH (sICH), and 5 (1.85%) patients had remote intracranial parenchymal hemorrhage (rPH). Logistic regression analysis showed that the risk of any ICH increased with increasing cSVD score [per unit increase, adjusted odds ratio (OR) 2.03, 95% CI 1.22–3.41, P = 0.007]. Sensitivity analyses using E-value revealed that it would need moderately robust unobserved confounding to render the exposure-outcome (cSVD-any ICH) association null. ROC analysis showed that compared with the National Institutes of Health Stroke Scale (NIHSS) score alone, a combination of cSVD and NIHSS score had a larger area under the curve for any ICH (0.811, 95% CI 0.756–0.866 vs. 0.784, 95% CI 0.723–0.846, P = 0.0004). CONCLUSION: The total cSVD score is associated with an increased risk of any ICH after IVT and improves prediction for any ICH compared with NIHSS alone

Structure and dielectric properties of double A-site doped bismuth sodium titanate relaxor ferroelectrics for high power energy storage applications

From Crossref journal articles via Jisc Publications RouterArticle version: AMFunder: Queen Mary, University of London; FundRef: 10.13039/501100000851; Grant(s): MRI studentshipFunder: Science and Technology Facilities Council; FundRef: 10.13039/501100000271; Grant(s): RB1620158The structural and dielectric properties of barium/strontium substituted Bi0.5Na0.5TiO3 were examined in compositions of general formula (Ba0.4Sr0.6TiO3)x(Bi0.5Na0.5TiO3)1−x

A bibliometric analysis of research on heart failure comorbid with depression from 2002 to 2021

Heart failure (HF) with depression is a common comorbidity associated with worse clinical status and quality of life. Although there have been numerous high-quality studies and relevant reviews on HF comorbid with depression, few bibliometric analyses of this field have been reported. In order to understand the development process, research hotspots and future directions, this review analyzes the papers on HF comorbid with depression from January 2002 to December 2021 through CiteSpace and VOSviewer. Visual cooperative networks between countries, authors and institutions were conducted to understand the basic development status of HF comorbid with depression. Furthermore, we performed co-occurrence analysis, burst detection, and timeline analysis for keywords to understand this field's research directions and hotspots. Finally, a detailed review and analysis of the classical literature in this field were conducted based on co-citation analysis. This bibliometric analysis provides an overview of studies on HF comorbid with depression and emphasizes the research on comorbidity mechanisms and more effective interventions as a priority for future research

Sequential Changes of Serum Tumor Markers Before and After the Radioactive 125I-seed Implantation in the Treatment of Lung Cancer

Background and objective The brachytherapy with iodine seeds is characterized by radioactive 125I very close to or in contact with the target organ. This study is to evaluate the clinical value of implanted radioactive 125I-seed in the treatment of lung cancer patients. Methods Sixty-three cases of lung cancer were enrolled in this study, and in every case, 125I-seeds were planted into tumor mass guided by CT. Serum CEA, CA125, NSE and CYFRA21-1 weredetected by radioimmunoassay in lung cancer patients before and after planting. The therapeutic effect was evaluated by WHO standards. The relation between the therapeutic effect and the tumor markers levels was observed. Results Just one month after planting, the levels of serum CEA, CA125, NSE and CYFRA21-1 were induced significantly in all cases. There was no significant difference among 1 month, 3 month and 6 month in the levels of tumor markers after therapy. Conclusion 125I-seed could effectively decrease the level of tumor markers in the treatment of lung cancer patients