Time T1 Research Articles

Effects of different doses of alfentanil on cardiovascular response to rapid sequence intubation in elderly patients: a parallel-controlled randomized trial

BackgroundRapid sequence intubation (RSI) have been shown to be effective in preventing reflux aspiration in patients with a full stomach during anaesthesia induction and endotracheal intubation. However, there is currently no standardized operation protocol or anaesthesia induction drug standard for RSI. Furthermore, there is a lack of evidence regarding the use of RSI in patients older than 65. In this study, we aimed to investigate the cardiovascular effects of different doses of alfentanil combined with propofol and etomidate during RSI in elderly patients aged 65–80 years.MethodsA total of 96 patients aged 65–80 years who underwent general anaesthesia with tracheal intubation were selected for this study. The patients were randomly assigned to one of four groups using a random number table. Group A patients received an induction dose of 10 µg/kg alfentanil, group B patients received 15 µg/kg alfentanil, group C patients received 20 µg/kg alfentanil, and group D patients received 25 µg/kg alfentanil. Heart rate (HR), mean arterial pressure (MAP), cardiac index (CI), and ejection fraction (EF) were measured at three time points: 5 min before anaesthesia induction (T0), 1 min after endotracheal intubation (T1), and 5 min after endotracheal intubation (T2). Concurrently, 4 ml of arterial blood was collected from patients at three time points, and the concentrations of norepinephrine (NE) and cortisol (Cor) in plasma were detected. Occurrences of hypertension, hypotension, bradycardia and tachycardia during anesthesia induction to 5 min after tracheal intubation were noted.ResultsCompared with T0, the HR, MAP, NE and Cor concentrations in group A and group B were increased at the T1 and T2 time points, CI and EF values were decreased (P < 0.05). HR and MAP in groups C and D were increased at the T1 time point, while they were decreased at the T2 time point in group D (P < 0.05). The changes in CI and EF values, concentrations of NE and Cor, were not significant at T1 and T2 time points in group C (P > 0.05). Additionally, they were not significant in group D at the T1 time point (P > 0.05), but decreased at the T2 time point (P < 0.05). Compared with group A, the HR, MAP, NE and Cor concentrations in groups C and D were decreased at T1 and T2 time points (P < 0.05). The CI and EF values of groups C and D were increased at T1 time point but decreased at T2 time point in group D (P < 0.05). The incidence of hypertension and tachycardia in group A was significantly higher than that in group C and group D (P < 0.05), and the incidence of hypotension and bradycardia in group D was significantly higher than that in group A and group B (P < 0.05).ConclusionAlfentanil 20 µg/kg for RSI in elderly patients, can effectively inhibit the violent cardiovascular reaction caused by intubation, and avoid the inhibition of cardiovascular system caused by large dose, hemodynamics more stable.Trial registrationChiCTR2200062034 (www.chictr.org.cn).

Investigation of bone remodeling in gingival crevicular fluid in patients treated with rapid maxillary expansion during pubertal period

Purpose: We aimed to evaluate bone remodeling following 3-month and 6-month retention periods of rapid maxillary expansion (RME) in gingival crevicular fluid (GCF). Materials and Methods: 23 pubertal participants (15 girls- 8 boys, 12-15 years) with maxillary transversal deficiency were enrolled in the study. Following banded-type RME appliance was introduced into the mouth, RME protocol was initiated by turning the Hyrax screw twice daily (morning/evening) with ¼ activation. GCF samples were taken from right maxillary first molars at four different time points (T0: before the appliance was deployed, T1: following active phase, T2: at the end of the 3-month retention period, T3: at the end of the 6-month retention period) using paper strips. Probing depth, gingival index, plaque index, and bleeding percentage at probing were recorded. BALP, OPG, RANKL, and TNF-α levels were measured in GCF samples using ELISA kits. Results: Our study revealed that GCF's BALP and OPG levels remained unchanged over time in tension and pressure regions, and there were no statistically significant differences among regions at each time point (p&gt;0.05). RANKL level was statistically significantly increased in the buccal region (the pressure region) at time T1 (p=0.042). The palatinal region's TNF-α level was statistically significantly higher than the buccal region at T0, T2, and T3 time points (p=0.005, p=0.042, and p=0.006, respectively). Our study showed no correlation between 3-month and 6-month retention periods and biomarkers indicating RME's bone metabolic activities. Conclusions: Further studies with different retention periods and larger sample sizes are suggested.

Role of Qualitative and Quantitative Indocyanine Green Angiography to Assess Mastectomy Skin Flaps Perfusion: A Prospective Monocentric Experience.

Mastectomy skin flap (MSF) necrosis remains a significant complication in breast reconstruction. This study aims to identify a correlation between the qualitative and quantitative analysis of the MSF perfusion grade and the skin necrosis rate 1 month after surgery using indocyanine green angiography (ICGA), focusing on lag time and perfusion metrics. Consecutive women scheduled for nipple/skin-sparing/skin-reducing mastectomy between May 2020 and October 2022 were prospectively enrolled. Patients were divided into Group 1 in the absence of superficial and full-thickness necrosis (SN; FTN) and Group 2 in the presence of both. Demographic data, lag time T1 (time between ICG injection and the initial perfusion of the least perfused MSF area), ICG-Q1, and ICG-Q% (absolute and relative perfusion values of the least vascularized area) were collected. 76 breasts were considered. FTN was reported in 8 breasts (10.5%) and SN in 4 (5.2%). The 2 groups statistically differ in T1 (Group2 > Group1), ICG-Q1, and ICG-Q% (Group1 > Group2) (P < 0.05). T1 longer than 170 seconds, body mass index, previous chemo/radiotherapy, arterial hypertension, breast weight, type of surgery, and ICG quantitative values can help in predicting MSF necrosis. MSF qualitative and quantitative perfusion evaluation can be helpful to prevent MSF necrosis. However, it should be considered together with the patient's characteristics, the type of surgery, and T1. In this way, it is possible to predict the risk of MSF necrosis and plan the best reconstructive strategy.

Investigation of Absorbable and Non-Absorbable Multifilament Suture Materials in Terms of Strength Changes Using Chlorhexidine Mouthwash and Thermal Cycling: An In Vitro Study.

Sutures are natural or synthetic biomaterials utilized to hold tissues together. Following oral surgery, the surgical site and sutures are physically affected by many different factors. This study was conducted to evaluate the effect of artificial saliva (AS) and chlorhexidine mouthwash on the tensile strength of absorbable multifilament PGLA (polyglycolide-co-l-lactide) and non-absorbable multifilament silk sutures. PGLA and silk sutures, which are commonly used in oral surgery, were used to evaluate the change in strength of the sutures. A total of 352 suture samples were divided into eight equal groups (n = 44) and used for the experiments. Tensile strength was tested on days 0, 3, 7, and 14. For the silk sutures, there was a significant decrease in tensile strength in all groups at time T3 compared to T0, T1, and T2, and at times T1 and T2 compared to T0. For PGLA sutures, there was a significant decrease in all groups at time T3 compared to T0, T1, and T2. This study shows that chlorhexidine mouthwash significantly reduces suture resistance for 14 days after surgery.

Surface roughness of different types of resin composites after artificial aging procedures: an in vitro study

BackgroundThe temperature changes, chemical agents, and brushing activity that resin composite restorations are exposed to in the oral environment can cause changes in surface roughness. In this study, the aim was to investigate in vitro the clinical one-year surface roughness changes of different types of composites (flowable or conventional) from the same companies by subjecting them to immersion in solutions, brushing, and thermal cycling procedures to simulate intraoral conditions.MethodsFour different resin composite brands were included in the study using both their conventional (Charisma Smart, 3M Filtek Ultimate Universal, Omnichroma, Beautifil II) and flowable resin composites (Charisma Flow, 3M Filtek Ultimate Flowable, Omnichroma Flow, Beautifil Flow Plus F00), giving 4 groups with 2 types of resin composite in each. 40 samples were prepared for each group/resin type, for a total of 320 samples. After initial surface roughness measurements by a mechanical profilometer, the samples were divided into 4 subgroups (n = 10) and immersed in solutions (distilled water, tea, coffee, or wine) for 12 days. The samples were then subjected to 10,000 cycles of brushing simulation and 10,000 cycles of thermal aging. Surface roughness measurements were repeated after the procedures. For statistical analysis, the 3-way analysis of variance and the Tukey test were used (p < 0.05).ResultsIt was concluded that composite groups and types had an effect on surface roughness at time t0 (p < 0.001). At time t1, the highest surface roughness value was obtained in the Beautifil-conventional interaction. When the surface roughness values between time t0 and t1 were compared, an increase was observed in the Beautifil II and Beautifil Flow Plus F00, while a decrease was observed in the other composite groups.ConclusionComposite groups, types, and solutions had an effect on the surface roughness of resin composites. After aging procedures, it was concluded that the Beautifil group could not maintain the surface structure as it exceeded the threshold value of 0.2 μm for bacterial adhesion.

Evaluation of palate morphology in patients treated with leaf expander and hyrax expander: A geometric morphometric analysis.

The aim of this study was to evaluate changes in shape of the palatal vault after maxillary expansion with hyrax expander (HE) and leaf expander (LE), using 3D Geometric Morphometric Analysis. Overall, 250 patients (110 M, 140 F) with maxillary transverse deficiency were selected for this study. In this study, 127 subjects were treated with HE, 123 with LE. Digital dental models were obtained pre-treatment (T0) and after 12 months from the cementation of the device (T1) and processed by means of a digital scanner. Linear and morphometric analyses were conducted to determine the effects of each appliance on dental measurements and palatal shape, and a multiple linear regression was performed to analyse the influence of anchorage and appliance type on final shape. Morphometric analysis showed that there was a lowering of the palatal vault in the HE group, while in the LE group it remained unchanged: the difference in palatal shape at time T0 and T1 was statistically significant in both treatments (HE vs. LE). In the HE group, the change in shape also included the upper part of the palatal vault in the vertical dimension, while in the LE group the change in shape interested mainly palatal shelves and the lower portion of the palate. Both LE and HE produce clinically significant changes in the morphology of the palatal vault.

Abstract Tu101: Measuring Fibrosis Progression in Duchenne Cardiomyopathy Using Cardiac Magnetic Resonance in mice

Introduction: Transthoracic echocardiogram (TTE) is currently the gold standard for measuring cardiac function in mouse models of cardiomyopathy, however, it has its limitations. Challenges include poor acoustic windows, lower reproducibility, larger margin of error, and inability to accurately detect fibrosis. The detection of fibrosis is critical for assessing the severity of cardiac involvement and monitoring disease progression in Duchenne muscular dystrophy (DMD). Cardiac magnetic resonance imaging (CMR) can be used to more accurately measure cardiac function, chamber volumes, and tissue characterization to monitor the progression of fibrosis, including with parametric T1 mapping and late gadolinium enhancement (LGE). In this study, we have used a dystrophic mouse model (D2. mdx ) on the DBA/2J genetic background as a preclinical model of DMD. Hypothesis: We hypothesize that CMR can detect worsening cardiac function and signs of fibrosis in the left ventricle of D2. mdx mice compared to wildtype (DBA) controls. Methods: In a study group of 12 age-matched male mice (8 mdx, 4 DBA), CMR was performed with contrast to determine cardiac function and fibrotic developments in the heart. Results: D2. mdx mice displayed a higher left ventricular end-diastolic volume compared to DBA mice (32.8 ± 3.6 µL vs 27.4 ± 1.5 µL, p &lt; 0.05). Global longitudinal strain was decreased in D2. mdx compared to DBA mice (-11.0 ± 3.5% vs -18.2 ± 2.2%, p &lt; 0.05). Native T1 mapping (Fig 1A) showed significantly higher mean T1 times in D2. mdx mice compared to DBA controls (Fig 1B). LGE in the myocardium of the left ventricle was noted in 6 of 8 of the D2. mdx mice (Fig 1C), but not in DBA mice. Logistic regression modeling showed strong predictive value detecting LGE with increasing native T1 times (Fig 1D). Conclusion: CMR can detect tissue changes in D2. mdx myocardium representing fibrotic changes. Native T1 may be useful in longitudinal studies of antifibrotic therapies in these models.

Rheological behavior of the synovial fluid: a mathematical challenge

BackgroundSynovial fluid (SF) is often used for diagnostic and research purposes as it reflects the local inflammatory environment. Owing to its complex composition, especially the presence of hyaluronic acid, SF is usually viscous and non-homogeneous. The presence of high-molar-mass hyaluronan in this fluid gives it the required viscosity for its function as a lubricant. Viscosity is the greatest major hydraulic attribute of the SF in articular cartilage.MethodsEmpirical modeling of previously published results was performed. In this study, we explored the flow of a non-Newtonian fluid that could be used to model the SF flow. Analyzing the flow in a simple geometry can help explain the model’s efficacy and assess the SF models. By employing some viscosity data reported elsewhere, we summarized the dynamic viscosity values of normal human SF of the knee joints in terms of time after injecting hyaluronidase (HYAL) at 25°C. The suggested quadratic behavior was obtained through extrapolation. For accurate diagnosis or prediction, the comparison between three specific parameters (ai, t0, and ln η0) was made for normal and pathological cases under the same experimental conditions for treatment by addition of HYAL and for investigation of the rheological properties. A new model on the variation of viscosity on the SF of knee joints with time after injection of HYAL with respect to normal and postmortem samples at different velocity gradients was proposed using data previously reported elsewhere.ResultsThe rheological behavior of SF changes progressively over time from non-Newtonian to a Newtonian profile, where the viscosity has a limiting constant value (η0) independent of the gradient velocity at a unique characteristic time (t0 ≈ 8.5 h). The proposed three-parameter model with physical meaning offers insights into future pathological cases. The outcomes of this work are expected to offer new perspectives for diagnosis, criteria, and prediction of pathological case types through comparisons with new parameter values treated under the same experimental conditions as HYAL injection. This study also highlights the importance of HYAL treatment for better intra-assay precision.

Porous medium type reaction-diffusion equation: Large time behaviors and regularity of free boundary

We consider the Cauchy problem of the porous medium type reaction-diffusion equation∂tρ=Δρm+ρg(ρ),(x,t)∈Rn×R+,n≥2,m>1, where g is the given monotonic decreasing function with the density critical threshold ρM>0 satisfying g(ρM)=0. We prove that the pressure P:=mm−1ρm−1 in Lloc∞(Rn) tends to the pressure critical threshold PM:=mm−1(ρM)m−1 at the time decay rate (1+t)−1. If the initial density ρ(x,0) is compactly supported, we justify that the support {x:ρ(x,t)>0} of the density ρ expands exponentially in time. Furthermore, we show that there exists a time T0>0 such that the pressure P is Lipschitz continuous for t>T0, which is the optimal (sharp) regularity of the pressure, and the free surface ∂{(x,t):ρ(x,t)>0}∩{t>T0} is locally Lipschitz continuous. In addition, under the same initial assumptions of compact support, we verify that the free boundary ∂{(x,t):ρ(x,t)>0}∩{t>T0} is a local C1,α surface.

Association of Cardiac MRI-derived Aortic Stiffness with Early Stages and Progression of Heart Failure with Preserved Ejection Fraction.

Purpose To investigate if aortic stiffening as detected with cardiac MRI is an early phenomenon in the development and progression of heart failure with preserved ejection fraction (HFpEF). Materials and Methods Both clinical and preclinical studies were performed. The clinical study was a secondary analysis of the prospective HFpEF stress trial (August 2017 through September 2019) and included 48 participants (median age, 69 years [range, 65-73 years]; 33 female, 15 male) with noncardiac dyspnea (NCD, n = 21), overt HFpEF at rest (pulmonary capillary wedge pressure [PCWP] ≥ 15 mm Hg, n = 14), and masked HFpEF at rest diagnosed during exercise stress (PCWP ≥ 25 mm Hg, n = 13) according to right heart catheterization. Additionally, all participants underwent echocardiography and cardiac MRI at rest and during exercise stress. Aortic pulse wave velocity (PWV) was calculated. The mechanistic preclinical study characterized cardiac function and structure in transgenic mice with induced arterial stiffness (Runx2-smTg mice). Statistical analyses comprised nonparametric and parametric comparisons, Spearman correlations, and logistic regression models. Results Participants with HFpEF showed increased PWV (NCD vs masked HFpEF: 7.0 m/sec [IQR: 5.0-9.5 m/sec] vs 10.0 m/sec [IQR: 8.0-13.4 m/sec], P = .005; NCD vs overt HFpEF: 7.0 m/sec [IQR: 5.0-9.5 m/sec] vs 11.0 m/sec [IQR: 7.5-12.0 m/sec], P = .01). Increased PWV correlated with higher PCWP (P = .006), left atrial and left ventricular long-axis strain (all P < .02), and N-terminal pro-brain natriuretic peptide levels (P < .001). Participants with overt HFpEF had higher levels of myocardial fibrosis, as demonstrated by increased native T1 times (1199 msec [IQR: 1169-1228 msec] vs 1234 msec [IQR: 1208-1255 msec], P = .009). Aortic stiffness was independently associated with HFpEF on multivariable analyses (odds ratio, 1.31; P = .049). Runx2-smTG mice exhibited an "HFpEF" phenotype compared with wild-type controls, with preserved left ventricular fractional shortening but an early and late diastolic mitral annulus velocity less than 1 (mean, 0.67 ± 0.39 [standard error of the mean] vs 1.45 ± 0.47; P = .004), increased myocardial collagen deposition (mean, 11% ± 1 vs 2% ± 1; P < .001), and increased brain natriuretic peptide levels (mean, 171 pg/mL ± 23 vs 101 pg/mL ± 10; P < .001). Conclusion This study provides translational evidence that increased arterial stiffness might be associated with development and progression of HFpEF and may facilitate its early detection. Keywords: MR Functional Imaging, MR Imaging, Animal Studies, Cardiac, Aorta, Heart ClinicalTrials.gov identifier NCT03260621 Supplemental material is available for this article. © RSNA, 2024.

Estimating synthetic hematocrit and extracellular volume from native blood pool T1 times at 3 Tesla CMR: Derivation of a conversion equation, accuracy and comparison with published formulas

PurposeCalculation of extracellular volume fraction (ECV), a marker of myocardial fibrosis in cardiac magnetic resonance imaging (CMR), requires hematocrit (Hct). We aimed to correlate Hct levels with native blood T1 times, to derive a formula for estimating synthetic Hct (Hctsyn) and synthetic ECV (ECVsyn), to assess accuracy of ECVsyn and to compare our model with published formulas. MethodIn this retrospective study, a cohort of 250 CMR scans with T1 mapping (3T, MOLLI 5(3)3, endsystolic aquisition), was divided into a derivation and validation cohort. Native T1 times of the left ventricular blood pool (T1native,midLV) were correlated with Hct levels from blood sampling within 24 h (Hct24h) and a formula for calculation of Hctsyn was derived by linear regression. ResultsIn the derivation cohort (n = 167), Hct24h showed a good association with T1native,midLV (r = −0.711, p < 0.001). The resulting regression equation was Hctsyn = 1/T1native,midLV * 1355.52–0.310. In the validation cohort (n = 83), Hctsyn and Hct24h showed good correlation (r = 0.726, p < 0.001), while ECVsyn, and ECV24h demonstrated excellent correlation (r = 0.940, p < 0.001). ECVsyn had a minimal bias of 0.28 % and the misclassification rate (8.8 %) was comparable to the variability introduced by repeated Hct measurements (misclassification in 7.5 %). Applying published formulas in our cohort resulted in incorrect classification in up to 60 %. ConclusionWe provide a formula for estimating Hctsyn from native blood T1 on a 3T scanner. The measurement error of ECVsyn is low and comparable to the error due to retest variability of conventional Hct. Scanner- and sequence-specific formulas should be used.

Evaluation of Tensile Strength of Surgically Absorbable Suture Materials Used in Oral Surgery after Immersion in Different Beverages: An In Vitro Study.

Suture materials are natural or synthetic biomaterials used to close tissues together. After surgical procedures in the mouth, the surgical site and the sutures are physically affected by many different factors. This study was conducted to evaluate the effects of frequently consumed beverages on the tensile strength of monofilament PGLA (polyglycolide-co-l-lactide) and multi-filament PGCL (polyglycolide-co-caprolactone) absorbable sutures. In particular, PGLA and PGCL absorbable sutures, which are frequently used in oral surgery, were used to evaluate the change in the strength of suture materials. The suture materials were soaked in tea, coffee, and cola drinks five times a day for 5 min each and the rest of the time in artificial saliva. All suture materials were aged via thermal cycling. Tensile strengths were tested at 0, 3, 7, and 14 days. Mixed ANOVA (four replicates: within-group comparison and two factors: between-group comparison) was performed to evaluate the effects of groups and time on the tension levels of the Tekmon and Vicryl suture materials. Analysis of Variance was used for the within- and between-group comparisons, with the Bonferroni corrected t-test for multiple comparisons. For the PGCL suture material, there were significant decreases in tension levels in artificial saliva, tea, coffee, and cola at time T3 compared to T0, T1, and T2, and at T1 and T2 compared to T0. For the PGLA suture material, there were significant decreases in tension levels in artificial saliva, tea, coffee, and cola at time T3 compared to T0, T1, and T2. There was also a significant decrease in tension level at time T2 in cola compared to T0. The present study demonstrates that beverages significantly decrease the strength of suture materials for 14 days after surgery. In particular, cola decreased the resistance of the PGCL suture material more significantly in the first week when compared to other beverages.

Detrimental Increase of Spin-Phonon Coupling in Molecular Qubits on Substrates.

Molecular qubits are a promising platform for quantum information systems. Although single molecule and ensemble studies have assessed the performance of S = 1/2 molecules, it is understood that to function in devices, regular arrays of addressable qubits supported by a substrate are needed. The substrate imposes mechanical and electronic boundary conditions on the molecule; however, the impact of these effects on spin-lattice relaxation times is not well understood. Here we perform electronic structure calculations to assess the effects of a graphene (Cgr) substrate on the molecular qubit copper phthalocyanine (CuPc). We use a progressive Hessian approach to efficiently calculate and separate the substrate contributions. We also use a simple thermal model to predict the impact of these changes on the spin-phonon coupling from 0 to 200 K. Further analysis of the individual vibrational modes with and without Cgr shows that an overall increase in SPC between the vibrations modes of CuPc with the surface reduces the spin-lattice relaxation time T1. We explain these changes by examining how the substrate lifts symmetries of CuPc in the absorbed configuration. Our work shows that a surface can have a large unintentional impact on SPC and that ways to reduce this coupling need to be found to fully exploit arrays of molecular qubits in device architectures.

Impact of rehabilitation unit-based physical activity therapy versus symptomatic supportive treatment on older patients with advanced cancer: a non-randomized controlled study

ObjectivesRelatively few studies have investigated the effects of rehabilitation-based physical activity therapy as a treatment for older patients with advanced cancer. This study evaluated the effects of individualized precise and structured exercise interventions, prescribed by a rehabilitation physician, on fatigue, quality of life (QOL), and physical activity in older patients with advanced cancer.MethodsAfter admission to the rehabilitation department, older cancer patients were divided into groups receiving conventional symptomatic supportive therapy (SST) or physical activity therapy plus conventional symptomatic supportive therapy (PAT). The SST group was given symptomatic supportive treatment, exercised on their own, and were observed at home after their symptoms improved. The PAT group was required to implement physical exercise along with SST, involving 30 min of moderate-intensity exercise per day and 5 days per week, and were discharged after 4 weeks and instructed to continue to exercise outside the hospital. Cancer-related fatigue (CRF) at 4 and 8 weeks was the primary endpoint of the study, while the secondary endpoints included patients’ QOL, physical activity, and exercise adherence rate.ResultsSixty-five patients were included; 37 (56.92%) chose to enter the PAT group, and 28 (43.08%) chose to enter the SST group. After 4 and 8 weeks of treatment, CRF relief and QOL improvement were significantly better in the PAT group than in the SST group (p < 0.05), whereas global health status did not differ between the two treatment groups (T1: p = 0.84; T2: p = 0.92). Mild physical activity significantly increased for the PAT group at T1 and T2 (T1: p = 0.03; T2: p = 0.005). At the T2 time point, the PAT group exhibited a higher level of participation in moderate-intensity physical activities as well as a higher total leisure activity score (p < 0.05). Thirty-three patients (94.29%) completed the PAT exercise program during hospitalization. Only four (12.12%) patients achieved moderate-intensity exercise, while the other 29 (87.88%) patients were able to continue exercising after their exercise intensity was decreased.ConclusionsImplementation of precise and individualized exercise interventions, prescribed by the rehabilitation team, can lead to the reduction of CRF and improvement of QOL, and change in behavior related to physical activity.

Superior energy storage performance achieved in tungsten bronze SBCN-based ceramics through tape-casting

Simultaneously integrating outstanding energy storage density and good energy storage efficiency in advanced ferroelectrics is crucial to implementing the application of dielectrics in high-power pulse devices. In this work, (Sr0.5Ba0.5)2Ca0.5Nb5-xSbxO15 ceramics were designed and prepared by adopting the B sites substitution engineering together with combining strategies of tape-casting method and two-step sintering process. Benefiting from the refined grain size and high density, the breakdown field of (Sr0.5Ba0.5)2Ca0.5Nb4.8Sb0.2O15 (SBCNS0.2) was promoted to 400 kV/cm. By the substitution of Sb5+ in the B sites, the weaker interaction force of Sb-O bond in BO6 octahedral polar unit induced the occurrence of polar nanoregions (PNRs) at room temperature to strengthen the dielectric relaxation behavior. Then it is noteworthy that SBCNS0.2 ceramics simultaneously obtained excellent recoverable energy density (Wrec, 3.9 J/cm3), energy storage efficiency (η, 90.5 %), power density (PD, 156.0 MW/cm3), and current density (CD, 1356.7 A/cm2). In addition, the SBCNS0.2 ceramics exhibited an ultrafast discharge time (t0.9, 67 ns). These results reveal prospective potential of unfilled tungsten bronze SBCNS0.2 ceramics in power capacitor applications and provide an effective strategy for improving excellent energy storage properties from the perspective of preparation methods.

Optimization and validation of multi-echo, multi-contrast SAGE acquisition in fMRI.

The purpose of this study was to optimize and validate a multi-contrast, multi-echo fMRI method using a combined spin- and gradient-echo (SAGE) acquisition. It was hypothesized that SAGE-based blood oxygen level-dependent (BOLD) functional MRI (fMRI) will improve sensitivity and spatial specificity while reducing signal dropout. SAGE-fMRI data were acquired with five echoes (2 gradient-echoes, 2 asymmetric spin-echoes, and 1 spin-echo) across 12 protocols with varying acceleration factors, and temporal SNR (tSNR) was assessed. The optimized protocol was then implemented in working memory and vision tasks in 15 healthy subjects. Task-based analysis was performed using individual echoes, quantitative dynamic relaxation times T2 * and T2, and echo time-dependent weighted combinations of dynamic signals. These methods were compared to determine the optimal analysis method for SAGE-fMRI. Implementation of a multiband factor of 2 and sensitivity encoding (SENSE) factor of 2.5 yielded adequate spatiotemporal resolution while minimizing artifacts and loss in tSNR. Higher BOLD contrast-to-noise ratio (CNR) and tSNR were observed for SAGE-fMRI relative to single-echo fMRI, especially in regions with large susceptibility effects and for T2-dominant analyses. Using a working memory task, the extent of activation was highest with T2 *-weighting, while smaller clusters were observed with quantitative T2 * and T2. SAGE-fMRI couples the high BOLD sensitivity from multi-gradient-echo acquisitions with improved spatial localization from spin-echo acquisitions, providing two contrasts for analysis. SAGE-fMRI provides substantial advantages, including improving CNR and tSNR for more accurate analysis.

Dielectric properties during the heating process of savory and sweet coconut‐/almond‐based bread in the microwave region

AbstractFor microwave‐assisted heating, accurate knowledge of the dielectric properties (DPs) plays a key role for optimizing the heating process. In this paper, the DPs of four different bread dough formulations are presented from 300 MHz to 20 GHz. The base dough was prepared with almond powder, coconut powder, eggs, cashew nut powder, ghee butter, and cardamom. In addition, three more honey‐sweetened formulations were prepared with honey, goat milk and cacao. The DPs were measured during the complete baking process, from room temperature up to 80°C. It is shown that in all cases, ε′ and ε″ decrease as frequency increases. In addition, a second‐order Debye equation was extracted for all formulations showing two relaxation times (τ1 and τ2), which can be seen in the Cole–Cole plot. Moreover, it is shown that in all formulations, as temperature increases, ε′ and ε″ also increase, which is a typical trend for low moisture foods. Finally, the penetration depths are calculated for all formulations.Practical ApplicationsThe dielectric properties (DPs) of four different bread dough formulations are provided covering a wide band in the microwave range from 300 MHz to 20 GHz. DPs are useful for the development of microwave‐assisted heating applications, where prior knowledge of the DPs permits the optimization of the heating process. In addition, penetration depth is necessary as this parameter allows to calculate the maximum depth that the microwave energy will heat up the sample.

Enhancement of Charge-Discharge Properties and Temperature Stability of (Ba0.975Na0.05)Ti0.99Nb0.01O3 Ceramic by Doping High-Entropy Oxide

A bidirectional optimization strategy was adopted to fabricate (1-x)(Ba0.975Na0.05)Ti0.99Nb0.01O3)-xBi(Zn0.2Mg0.2Al0.2Sn0.2Zr0.2)O3(abbreviated as (1-x)BNNT-xBZMASZ, x = 0.02–0.10) ceramics, aimed to improve the energy storage performance. X-ray diffraction results revealed that Bi2+ cations entered the A site and the multiple cations occupied the B site of BNNT, thereby decreased the remnant polarization intensity and refined the hysteresis loop. Scanning electron microscopy images showed uniform morphologies with clear grain boundaries of the ceramics, and the average size decreased with x increasing. The substitution of multiple cations at the B-site induced the splitting of macroscopic ferroelectric domains into smaller polar nanodomains, leading to the formation of high-dynamic polar nanoregions and accelerating the transition from BNNT to relaxor ferroelectrics, thus improving relaxation properties of the material. The excellent energy storage density (Wrec ∼ 2.80 J cm−3) and efficiency (∼90.0%) can be obtained under 200 kV cm−1. Moreover, the discharge-charge testing revealed excellent current density (∼589.5 A cm−2), high power density (∼20.63 MW cm−2), and extremely short discharge time (t0.9 ∼ 50.4 ns), along with exceptional temperature stability and cycling stability under the equivalent electric field of 120 kV cm−1. The 0.92BNNT-0.08BZMASZ ceramic offers a new approach to the design and an improvement of pulsed dielectric capacitor materials.

The Uncertainty Evaluation of Determining the Trace H2S in SF6/N2 Insulating Gas Mixture by Cavity Ring-Down Spectroscopy

Abstract H2S is one of the most important characteristic components of sulfur hexafluoride gas insulated electrical equipment. The detection of trace H2S is of great significance for early fault diagnosis of such equipment. Based on the 1578 nm wavelength distributed feedback diode laser (DFB-DL), cavity ring-down spectroscopy (CRDS) can effectively measure the concentration of trace H2S in SF6/N2 gas mixtures. Starting from the principle of methodology, this article establishes a mathematical model for evaluating the measurement uncertainty of CRDS and analyzes its sources of uncertainty: gas constant R1 , temperature T, Avogadro constant NA , gas pressure p in the optical cavity, volume V of the optical cavity, speed c of light, the absorption cross-section parameter σ(ν) of H2S molecules in the laser frequency ν, the ring-down time τ with absorption sample H2S and the ring-down time τ0 without absorption sample. After evaluating the uncertainty components, it was found that the main component was σ(ν) and the secondary components were τ and τ0. The H2S content in the 80% SF6-20% N2 mixed gas measured is (7.64 ± 0.12) × 10−6 mol/mol.

Analysis of how Serum Ferritin and the Aspartate Aminotransferase-to-Platelet Ratio Index (APRI) are correlated to Hepatic MRI T2* Findings in Children with Beta-Thalassemia Major

Background: Iron overload is a major complication in patients with beta-thalassemia major. Excessive iron accumulation leads to organ dysfunction. The regular assessment of iron is crucial to effectively manage iron overload in these patients. This study evaluated the correlation between serum ferritin levels, the Aspartate Aminotransferase-to-Platelet Ratio Index (APRI), and hepatic MRI T2* findings in children with beta-thalassemia major. Materials and Methods: This retrospective analytical study was conducted at Shahid Sadoughi Hospital in Yazd in 2023. The research population comprised all the children under the age of 15 with beta-thalassemia major who had undergone multiple blood transfusions (at least ten units of blood). Results: The participants in this study were 70 children with beta-thalassemia major, including 35 males and 35 females. Their mean age was 3.52 ± 10.76 years. The mean relaxation time of liver MRI T2* was 4.42 ± 4.91 ms. The participants also had the APRI score of 0.55 ± 1.90, the aspartate aminotransferase (AST) level of 23.82 ± 36.29, and the serum ferritin level of 285.01 ± 3244.04 (ng/mL). Based on MRI T2* results, 30% of the patients had a severe liver iron overload, 27.1% had a moderate overload, 21.4% had a severe overload, 18.6% had a mild overload, and 2.9% had near-normal iron levels.The AST level demonstrated a significant association with the type of chelation treatment (P = 0.003). The duration of blood transfusion (in years) showed a strong positive correlation with the patients' age (Pearson's coefficient = 0.996). Conclusion: This study indicates the elevated serum ferritin levels and APRI scores in patients with beta-thalassemia major, most of whom have abnormal MRI T2* findings. However, no significant correlation was observed between the APRI score, serum ferritin level, and MRI T2* results.