Changes In Diffusion Coefficient Research Articles

Effects of uniaxial tensile strain on the release of small molecules from silicone rubber

AbstractSilicone rubber materials may be subject to mechanical strains which can affect the transport properties of small molecules loaded in the materials such as plasticizers and active molecules, hence deteriorating their intended mechanical properties or affecting their performance as carriers of active molecules. Therefore, it is important to understand the effects of mechanical strains on transport of small molecules in the silicone rubber matrix. In this work, silicone rubber sheets loaded with 2 wt% triacetin were stretched and held at four different lengths up to 125% engineering strain. The mass transfer coefficients and diffusion coefficients of triacetin in the strained silicone rubber were determined by monitoring the release of triacetin using headspace gas chromatography–mass spectrometry. It was found that there was no significant change of diffusion coefficient as the applied strain increased, which might result from two microstructure changes that had conflicting effects on diffusion: chain orientation and free volume deformation.

New insights from nanoscale in-depth investigation into wettability modification in oil-wet porous media

In the context of fluid-surface studies of oil reservoirs, wettability alteration plays an important role, especially in carbonate reservoirs. This investigation, utilizing molecular dynamics simulation, delves into the effect of oil movement during interactions with brine ions. The calculation of adsorption energy, radial distribution function, diffusion coefficient, and configurational changes of the NaCl brine molecules allowed for an examination of the role of ions in oil movement from an oil-wet calcite surface. Findings indicate that the polarity of oil has a marked influence on oil detachment, as evidenced by the more than 30% adsorption energy for the acrylic acid system compared to the decane system. The diffusion coefficient of Na[Formula: see text] ions in the acrylic acid system was found to be five times as high as in the decane system. Configuration changes showed that brine ions are more active — in a regular eight shape — in interacting with the acrylic acid-wet surface as opposed to the decane-wet surface. The hierarchical significance of oil polarity [Formula: see text] brine ions [Formula: see text] mineral surface in altering the wettability of the system demonstrates the significance of sodium ions in the presence of the polar oil component. The findings greatly contribute to the development of effective Smart Water flooding technology.

Polyimide aerogels with low thermal conductivity and high-temperature stable properties prepared by lyophilization for flexible thermal protection

Polyimide aerogel, presenting an outstanding new material for lightweight protective thermal insulation, has garnered significant attention in the aerospace field. Despite its potential, due to the high production cost of the supercritical drying method used for its preparation, its widespread application is limited. In this research, a series of lightweight polyimide aerogels (F-PIAs, 3,3',4,4'-biphenyl tetracarboxylic dianhydride (s-BPDA) and 4,4'-diaminodiphenyl ether (ODA)) with excellent thermal protection properties were prepared by lyophilization. The findings indicated that F-PIAs (Freeze-dried polyimide aerogels) exhibited comparable physical characteristics to S-PIAs (Supercritical-dried polyimide aerogels), while their preparation cost was even more economical. F-PIAs exhibits excellent flexible and compression behavior (compression strength up to 1.16 MPa, modulus up to 12.8 MPa), which provide a great structural basis for the production of molded thermal insulation protective materials. The average pore diameter of F-PIAs is in the range of 7∼11 nm. The nanoporous structure leads to the gas within the pores of the aerogel producing the Knudsen effect, thereby significantly enhancing the thermal insulation performance of the aerogel. The thermal conductivity of F-PIA-4 (Freeze-dried polyimide aerogels with a solid content of 4%) at room temperature is as low as 0.023 W·m−1·K−1, which is superior to the PIAs (0.043 W·m−1·K−1) prepared by lyophilization in literature. Its thermal diffusion coefficient changes from 0.108 mm2·s−1 to 0.18 mm2·s−1 in the temperature range of 27°C to 200°C, demonstrating good thermal insulation performance at high temperatures. Meanwhile, after heating on a 150°C flat plate for 11 min and 41 s, the surface temperature of F-PIA-4 was only 36.2°C, further verifying its excellent thermal insulation performance. The results of the TGA experiment on F-PIA-4 demonstrated the high-temperature stability of aerogel (Td5% is higher than 523°C, Td10% is higher than 566°C). The exceptional properties of F-PIAs hold significant practical reference value in helping to reduce the manufacturing cost of high-performance aerogel thermal insulation materials, thereby enabling their widespread application in aerospace, military, and civil field.

Longitudinal Monitoring of Quantitative Imaging Kinetics of Primary Tumor and Nodal Volumes Using the MR-Linac Device in Head and Neck Cancer Patients

We aim to characterize the serial quantitative apparent diffusion coefficient (ADC) changes of the target disease volume using diffusion-weighted imaging (DWI) acquired weekly during radiation therapy (RT) on a 1.5T MR-Linac and correlate these changes with tumor response and oncologic outcomes for head and neck squamous cell carcinoma (HNSCC) patients. Thirty patients with pathologically confirmed HNSCC and received curative-intent RT at the University of Texas MD Anderson Cancer Center, were included in this prospective study. Baseline and weekly MRIs (weeks 1-6) were obtained, and various ADC parameters (mean, 5th, 10th, 20th, 30th, 40th, 50th, 60th, 70th, 80th, 90th and 95th percentile) were extracted from the target regions of interest (ROIs). Pre-RT and weekly ADC parameters were correlated with response during RT, loco-regional control, and the development of relapse using the Mann-Whitney U test. The Wilcoxon signed-rank test was used to compare the weekly ADC versus baseline values. Weekly volumetric changes (Δvolume) for each ROI were correlated with ΔADC using Spearman's Rho test. Recursive partitioning analysis (RPA) was performed to identify the optimal ΔADC threshold associated with different oncologic outcomes. There was an overall significant rise in all ADC parameters during different time points of RT compared to baseline values for both GTV-P & GTV-N. The increased ADC values for GTV-P were statistically significant only for primary tumors achieving CR during RT. RPA identified GTV-P ΔADC 5th percentile >13% at the 3rd week of RT as the most significant parameter associated with CR for GTV-P during RT (p <0.001). Baseline ADC parameters didn't significantly correlate with response to RT or other oncologic outcomes. There was a significant decrease in residual volume of both GTV-P & GTV-N throughout the course of RT. Additionally, a significant negative correlation between mean ΔADC and Δvolume for GTV-P at the 3rd and 4th week of RT was detected (r = -0.39, p = 0.044 & r = -0.45, p = 0.019, respectively). Assessment of ADC kinetics at regular intervals throughout RT is potentially able to predict the response to RT and oncologic outcome. Further studies with larger cohorts and multi-institutional data are needed for validation of our results.

Relationship between apparent diffusion coefficient and survival as a function of distance from gross tumor volume on radiation planning MRI in newly diagnosed glioblastoma.

To investigate the changes in apparent diffusion coefficient (ADC) within incrementally-increased margins beyond the gross tumor volume (GTV) on post-operative radiation planning MRI and their prognostic utility in glioblastoma. Radiation planning MRIs of adult patients with newly diagnosed glioblastoma from 2017 to 2020 were assessed. The ADC values were normalized to contralateral normal white matter (nADC). Using 1mm isotropic incremental margin increases from the GTV, the nADC values were calculated at each increment. Age, ECOG performance status, extent of resection and MGMT promoter methylation status were obtained from medical records. Using univariate and multivariable Cox regression analysis, association of nADC to progression-free and overall survival (PFS, OS) was assessed at each increment. Seventy consecutive patients with mean age of 53.6 ± 10.3 years, were evaluated. The MGMT promoter was methylated in 31 (44.3%), unmethylated in 36 (51.6%) and unknown in 3 (4.3%) patients. 11 (16%) underwent biopsy, 41 (44%) subtotal resection and 18 (26%) gross total resection. For each 1mm increase in distance from GTV, the nADC decreased by 0.16% (p < 0.0001). At 1-5mm increment, the nADC was associated with OS (p < 0.01). From 6 to 11mm increment the nADC was associated with OS with the p-value gradually increasing from 0.018 to 0.046. nADC was not associated with PFS. The nADC values at 1-11mm increments from the GTV margin were associated with OS. Future prospective multicenter studies are needed to validate the findings and to pave the way for the utilization of ADC for margin reduction in radiation planning.

Diffusion-weighted MRI at the Late Stage after Radiotherapy for Evaluating Salivary Gland Injury.

Salivary gland injury is the main complication of radiotherapy for nasopharyngeal carcinoma (NPC) patients. The purpose of this study was to evaluate the value of diffusion-weighted magnetic resonance imaging (DW-MRI) as a reliable tool to assess salivary gland function in NPC patients after radiotherapy. This study analysed the MR images of 31 NPC patients at different time points within 2-3 years after radiotherapy. The changes in the apparent diffusion coefficient (ADC) and its relationship with radiation dose were analysed. Both the parotid and submandibular gland ADC values increased significantly 3-6 months after radiotherapy and then decreased gradually. The ADC value of the parotid gland was positively correlated with radiation dose at the late stage (P = 0.012, r = 0.359). The submandibular gland ADC change value (P = 0.035) and change ratio (P = 0.027) of the high radiation dose group were significantly lower than those of the low dose group at the late stage. The correlation between ADC values of parotid and submandibular glands and the radiation dose indicated that DW-MRI could be helpful in evaluating salivary gland injury after radiotherapy.

Effect of Different Drying Systems on Drying Performance of Maraş Green Pepper (C.annum)

Drying is the simultaneous transfer of heat and mass, which is defined as the reduction of moisture in food. The aim of the study the drying performances of refractance window drying (95°C), fluidized bed drying (95°C, 2m3/m air velocity), and convective drying (95°C) were examined in the drying of Maraş green pepper (C.annuum). Drying performance was evaluated for effective diffusion coefficient (Deff), activation energy (Ea), Chroma (C) and total color change (ΔE). Drying curves were obtained by recording sample weights in 10-min periods. For the refractance window drying, fluidized bed drying and convective drying the time for the samples to reach 6-7% humidity level according to the wet base was found to be 70, 80 and 110min, and the effective diffusion coefficient was 6.49x10-10, 5.68x10-10 and 4.87x10-10 m2/s the activation energy was 53.54, 54.65 and 55.93kJ/mol, respectively. When the color properties are examined the Chroma value was determined as 18.23, 8.85 and 4.80 and the total color as 15.42, 26.29 and 30.33, respectively. It was seen that the closest value to the fresh product was in the samples dried with a refractance window drying. In the study, it was concluded that the use of a refractance window drying shortened the drying time by 14-36%, increased the effective diffusion coefficient, provided drying with lower activation energy, and better preserved the color quality in the production of dried Maraş green pepper.

Effect of Soil Volumetric Water Content on the CO2 Diffusion Coefficient

Purpose: The soil air diffusion coefficient (Ds) is particularly important for the study of soil gas diffusion movement, and there are still many uncertainties in the widely used methods; as such, a method was designed to in situ measure the soil gas diffusion coefficient. Methods: Four different soil media were selected and studied by means of a designed in situ measurement of soil gas diffusion coefficients, and these were compared and analyzed with the predictions of several commonly used prediction models. In addition, they were combined with gas transport models to validate the results of the empirical models that were obtained by the in situ measurements. Results: The results of the data indicate that increasing the volumetric soil moisture content decreases the soil gas diffusion coefficient, with changes in the soil gas diffusion coefficient for the small-grained quartz sand medium being similar to those predicted by the Buckingham model. The soil gas diffusion coefficients for the large-grained quartz sand were similar to the Millington and Quirk model predictions at low humidity; for increased humidity, it was instead similar to the Buckingham model predictions. The soil gas diffusion coefficients of the two active media were closer to those of the SWLR model with high Cm. In addition, the R2 of the measured data was verified, by empirical modeling, to be greater than 0.54, and inversion experiments were conducted to verify that the results were consistent with those of the SWLR model. Conclusion: When measuring relative diffusion coefficients in the field, we recommend the in situ measurement method, which is more reflective of the actual situation in natural environments and provides more accurate data support for soil carbon flux studies.

Early MRI Predictors of Relapse in Primary Central Nervous System Lymphoma Treated with MATRix Immunochemotherapy.

Primary Central Nervous System Lymphoma (PCNSL) is a highly malignant brain tumour. We investigated dynamic changes in tumour volume and apparent diffusion coefficient (ADC) measurements for predicting outcome following treatment with MATRix chemotherapy in PCNSL. Patients treated with MATRix (n = 38) underwent T1 contrast-enhanced (T1CE) and diffusion-weighted imaging (DWI) before treatment, after two cycles and after four cycles of chemotherapy. Response was assessed using the International PCNSL Collaborative Group (IPCG) imaging criteria. ADC histogram parameters and T1CE tumour volumes were compared among response groups, using one-way ANOVA testing. Logistic regression was performed to examine those imaging parameters predictive of response. Response after two cycles of chemotherapy differed from response after four cycles; of the six patients with progressive disease (PD) after four cycles of treatment, two (33%) had demonstrated a partial response (PR) or complete response (CR) after two cycles. ADCmean at baseline, T1CE at baseline and T1CE percentage volume change differed between response groups (0.005 < p < 0.038) and were predictive of MATRix treatment response (area under the curve: 0.672-0.854). Baseline ADC and T1CE metrics are potential biomarkers for risk stratification of PCNSL patients early during remission induction therapy with MATRix. Standard interim response assessment (after two cycles) according to IPCG imaging criteria does not reliably predict early disease progression in the context of a conventional treatment approach.

Paediatric supratentorial tumours do not cause microstructural alterations in contralateral white matter: a preliminary study.

Intracranial tumours in children can exhibit different characteristics compared to those in adults. Understanding the microstructural changes in the contralateral normal-appearing white matter (NAWM) in children with primary intracranial masses is essential for optimizing treatment strategies. This study aimed to investigate the apparent diffusion coefficient (ADC) changes in contralateral NAWM using fully automated methods and deep learning algorithms. We included 22 paediatric patients with primary supratentorial intracranial masses (23% high-grade) in the study. ADC values of the contralateral NAWM in the patient group were compared to those of a control group. Deep learning algorithms were utilized to analyse diffusion changes in NAWM. The mean ADC values of contralateral NAWM in the patient group were 0.80 ± 0.03 × 10-3 mm2/s, while the control group had a mean ADC value of 0.81 ± 0.03 × 10-3 mm2/s. There was no statistically significant difference between the groups (p = 0.39). Our findings indicate that there are no significant diffusion changes in the contralateral white matter of children with supratentorial intracranial masses. Primary supratentorial intracranial masses in children do not cause microstructural changes in contralateral normal-appearing white matter. This could be attributed to the less infiltrative nature and different biochemical profile of these tumour groups in the paediatric population. Further studies using advanced imaging techniques could provide additional insights into the distinct characteristics of paediatric intracranial tumours and improve patient management.

Magnetic Resonance Diffusion Tensor Imaging Characterize the Hepatic Ischemia-Reperfusion Injury in an Animal Study

Hepatic ischemia-reperfusion (I/R) injury is the main cause of morbidity and mortality after hepatectomy; thus, new methods for reducing I/R injury are required. The aim of this study is to evaluate changes in the average apparent diffusion coefficient (ADCavg) and fractional anisotropy (FA) in rabbits with partial hepatic I/R injury with magnetic resonance diffusion tensor imaging (DTI). The left lobe of the rabbit liver underwent 60 minutes of ischemia followed by 0.5, 2, 6, 12, 24, and 48 hours of reperfusion. T2-weighted images (T2WI), T1-weighted images (T1WI), DTI, and contrast-enhanced T1WI were performed; 6 b values were used for DTI on 6 diffusion directions. The serum levels of transaminases and liver histopathology findings were examined. In the early stage of I/R (0.5 hour), ADCavg decreased significantly and increased sharply to 2 hours, then increased from 6 hours to 48 hours of reperfusion, except for a transient decrease (24 hours). Meanwhile, FA showed almost the opposite trend, drastically increasing during the first 0.5 hour and then slightly decreasing until 48 hours of reperfusion, except for an obvious decrease in the 2-hours group. The serum levels of liver markers and the pathologic scores were sharply increased in the I/R group after reperfusion and correlated with DTI of hepatic tissue after I/R. Diffusion tensor imaging is feasible for imaging I/R-induced liver damage and can discriminate isotropic properties of the liver after I/R injury with objective changes in the ADCavg and FA. Diffusion tensor imaging can be a promising novel approach for use in clinical management after liver surgery.

Restaging of rectal cancer with hybrid positron emission tomography magnetic resonance imaging after preoperative chemoradiotherapy.

This study determines the sensitivity and specificity of positron emission tomography/magnetic resonance imaging (PET/MRI) parameters in predicting treatment response in patients with localised rectal cancer who have undergone preoperative chemoradiotherapy (CRT). Patients with stage I-III adenocarcinoma of the rectum planned for preoperative CRT followed by surgery were recruited. Patients had PET/MRI scans at baseline and 6-8 weeks post-CRT. Functional MRI and PET parameters were assessed for their diagnostic accuracy for tumour regression grade (TRG). Nonparametric receiver operating characteristic analysis was employed to determine the area under the ROC curve (AUC), and the sensitivity and specificity of each quantile cut-off. A total of 31 patients were recruited, of whom 20 completed study protocol. All patients included had mid or lower rectal tumours. There were 16 patients (80%) with node-positive disease at presentation. The median time to surgery was 75.5 days (range 52-106 days). Histopathological assessment revealed 20% good responders (TRG 1/2), and the remaining 80% of patients had a poor response (TRG 3/4). When predicting good responders, the AUC values for percent maximum thickness reduction and percent apparent diffusion coefficient (ADC) change were 0.82 and 0.73, respectively. A maximum thickness reduction cut-off of >47% and a percent ADC change of >20% yielded a sensitivity and specificity of 75%/95% and 75%/73%, respectively. Parameters such as percent maximum thickness reduction and percent ADC change may be useful for predicting good responders in patients undergoing preoperative CRT for rectal cancer. Larger studies are warranted to establish the utility of PET/MRI in rectal cancer staging.

Microwave drying method investigation for the process and kinetics of drying characteristics of zinc-leaching residue.

Due to the high moisture content in the zinc-leaching residue, it is easy to cause safety problems when directly entering the kiln. Microwave drying can minimize particle agglomeration and promote cracks on the mineral surface, which benefits the subsequent recovery and smelting of zinc-leaching residue. The results showed that increasing microwave power and particle size range could improve the maximum drying rate and reduce the drying time. The maximum drying rate of 20g zinc-leaching slag with a microwave power of 700 W, a particle size of 1-10mm, and a moisture content of 20% can be higher than 0.365%/s and reach complete drying within 120s. The drying results were fitted and statistically analyzed using nine common kinetic models of drying, the surface diffusion coefficient changes were further analyzed at four levels, and the reaction activation energy (Ea) was calculated. According to Fick's second law, when the average particle size increased from 0.044 to 5.5mm, the surface diffusion coefficient increased from 6.2559 × 10-9 to 3.8604 × 10-6 m2/s, which showed that the effect of particle size change on microwave drying process was significant. The Ea of the drying reaction was 18.1169kJ/mol. This method provides an idea for efficiently treating secondary resources containing valuable metals.

Regional changes in brain apparent diffusion coefficient in fetuses with complex congenital heart disease and normal pregnancy assessed using diffusion-weighted imaging.

To explore changes in brain apparent diffusion coefficient (ADC) in normal fetuses and fetuses with complex congenital heart disease (CHD) during the second and early third trimesters. This single-center prospective study was conducted from May 2019 through October 2021. We measured and compared the mean ADC values between 23 fetuses with CHD and 27 gestational age (GA)-matched controls using covariance analyses. ADC density plots and histograms were used to compare brain characteristics. False-discovery rates (FDR, α = 0.05) correction was used for multiple testing. The mean ADC in the frontal white matter, temporal white matter, parietal white matter, occipital white matter, cerebellar hemisphere, central area of the centrum semiovale, basal ganglia region, thalamus, and pons were not significantly different (all p > 0.05). Based on histogram analysis, there were no significant differences between the controls and fetuses with CHD after FDR correction. However, the ADC density plots showed significant heterogeneity between the controls and fetuses with CHD. The mean ADC values and ADC histogram analysis did not differ between the CHD and normal groups. The ADC density plots may provide supplementary information and improve the sensitivity for detecting early brain changes in fetuses with CHD.

Unveiling the molecular interactions of surface wetting modification in porous medium: A groundbreaking insight into wettability alteration

Recently, discussions have been raised surrounding the cause of changing wettability during brine salinity engineering. The goal of this study is to decode the reason behind wettability changes by introducing a novel approach involves both monovalent (Na+) and divalent (Ca2+) ions. Through molecular dynamics simulations, the study investigates the underlying physiochemical interactions responsible for wettability modification via configuring the amorphous cells and integrated layers. Various metrics were analyzed including the radial distribution function, diffusion coefficient, adsorption energy, mixing energy, solubility parameter, and molecular configurational changes. The results demonstrate the significant influence of oil polarity and the role of sodium ions with a maximum diffusivity of 1.2 × 10−4 cm2/s. Calculations reveal that sodium chloride ions are two orders of magnitude more active than calcium chloride ions. The most notable finding of this study involves the identification of two new mechanisms termed the "brine Prong" and "oil Vortex" effects that play a crucial role in separating oil from the surface and inducing changes in the wetting state. Overall, the results offer significant insights into the fields of engineering water flooding and the interaction between brine, oil, and rock to elucidate the wettability alteration phenomenon in porous medium and secure enhancement of oil production.

The impact of the apparent diffusion coefficient for the early prediction of the treatment response after definitive radiotherapy in prostate cancer patients

PurposeWe assessed early changes in apparent diffusion coefficient (ADC) and serum prostate specific antigen (PSA) values after definitive radiotherapy (RT) without androgen deprivation treatment in low- and intermediate-risk prostate cancer (PC) patients. Materials and MethodsThe clinical data and ADC parameters of 229 PC patients were retrospectively evaluated. Pre-treatment and post-treatment serum PSA and primary tumor ADC values were calculated. Post-treatment DW-MRI was performed median 4.1 months after completion of definitive RT. The prognostic factors predicting freedom from biochemical failure (FFBF) and progression-free survival (PFS) were analyzed using univariable and multivariable analyses. ResultsWith a median follow-up time of 80.8 months, the 5-year FFBF and PFS rates were 95.9% and 89.3%, respectively. Eleven patients (4.8%) had PSA relapse, with a median of 34.4 months after the completion of RT. A statistically significant difference in post-treatment ADC values was noted between patients with and without recurrence (0.94 ± 0.07 vs. 1.10 ± 0.20 × 10-3 mm2/sec; p< 0.001). Patients with a Gleason score (GS) of 6 and low-risk disease had significantly higher post-treatment tumor ADC and PSA levels than patients with a GS of 7 and intermediate-risk disease. The 5-year FFBF rate in patients with tumor ADC ≤ 0.96 × 10-3 mm2/sec was significantly lower than patients with tumor ADC > 0.96 × 10-3 mm2/sec (85.5% vs. 100; p< 0.001). In the multivariable analysis, a lower ADC value, GS 4 + 3 and intermediate-risk disease were independent predictors of worse FFBF. In the multivariate analysis, a lower post-treatment ADC value and a GS of 4 + 3 were significant prognostic factors for a lower PFS. ConclusionThese findings suggest that the post-treatment tumor ADC value could be used for early treatment response evaluation after definitive RT in PC patients.

MR-Guided Transurethral Ultrasound Ablation of Prostate Cancer: Initial Experience of Monitoring Tumor Response by Dynamic Apparent Diffusion Coefficient Measurements at 3.0 T

Introduction: Diffusion-weighted imaging (DWI) as part of multiparametric magnetic resonance imaging (mpMRI) is an important sequence for the detection of prostate cancer (PCa). The objective of this retrospective analysis was to evaluate changes in apparent diffusion coefficient (ADC) measurements in biopsy-proven PCa undergoing TULSA-PRO (MR-guided transurethral ultrasound ablation of the prostate) at 3.0 T after 1, 3, and 6–12 months posttreatment. Methods: Nineteen patients underwent follow-up examinations after 1, 3, and 6–12 months including mpMRI at 3.0 T and urological-clinical examinations with quantitative analysis of ADCs. Results: In PCa, a significant increase of ADC values after 6–12 months was measured after TULSA-PRO treatment by 29.1% (pre-TULSA: 0.79 ± 0.16 × 10−3 mm2/s, 6–12 months: 1.02 ± 0.35 × 10−3 mm2/s), while the corresponding value in the reference tissue decreased by 48.5% (pre-TULSA: 1.20 ± 0.15 × 10−3 mm2/s, 6–12 months: 0.91 ± 0.29 × 10−3 mm2/s). The mean ADC values in the early follow-up groups at 1 and 3 months did not change significantly. Conclusion: DWI with ADC as part of mpMRI can serve as a biomarker to dynamically monitor the follow-up after TULSA after 6–12 months. For early posttreatment progression, it is not suitable due to too many confounding variables.

S doped CNTs scaffolded Si@C spheres anode toward splendid High-Temperature performance in Lithium-ion Battery

The poor electronical conductivity and large volume change of nano-silicon anode has seriously hindered its further application. To overcome these drawbacks, we employed the S-doped multiwalled carbon nanotubes (SCNTs) as the conductive additive to fabricating a scaffolded framework for the first time. The as-assembled Si anode with 5 wt% SCNTs (Si@C-5SCNTs) shows a large specific capacity of 939 mA h g−1 at 2 A g−1 within 0–1 V, significantly higher than that of Si@C (466 mA h g−1) and Si@C-5CNTs (720 mA h g−1), showing a superior rate performance. Besides, it shows higher initial coulombic efficiency, Li-ion diffusion coefficient, cycling performance, and smaller volume change than that of Si@C and Si@C-CNTs at room temperature. Even at 40 ℃, the Si@C-5SCNTs anode still show a superior rate performance (1842 and 819 mAh g−1 at 0.05 and 2 A g−1, respectively) and cycling stability (83.6% capacity retention) than that of Si@C and Si@C-5CNTs. To better explain the significantly enhanced electrochemical performance of Si anode both room and high temperature conditions, both the chemo-mechanical coupling and internal temperature distribution models have been rational constructed, and further demonstrated that the SCNTs can effectively buffer the volume expansion and reduce the internal local temperature rise.

Cobalt Electrodeposition in Nanoporous Anodic Aluminium Oxide Films with Different Oxidation Time

The anodic aluminum oxide films with different oxidation times were investigated using electrochemical techniques including electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and open-circuit potential versus time. The stable open-circuit potential versus time indicates that the longer anodization time provides a larger block for cobalt electrodeposition. The EIS monitoring revealed the capacitance characteristics of the barrier layer. When the oxidation time is 4 h, the thickness and porosity of AAO film are 1517 nm and 16.4 % corespondingly, and the radius of the capacitive reactance arc is the smallest. The reduction peak current of CV is attributed to the change in diffusion coefficient of cobalt when oxidation time changes.

Cellular nitric oxide synthesis is affected by disorders in the interdependent [Formula: see text] and [Formula: see text] dynamics during cystic fibrosis disease.

Calcium ([Formula: see text]), inositol trisphosphate ([Formula: see text]), and nitric oxide (NO) signaling are essential to maintain the structural integrity and physiological activity of fibroblast cells. The accumulation of excess quantity of NO for longer periods can lead to a variety of fibrotic disorders, including heart disease, penile fibrosis in Peyronie's disease (PD), and cystic fibrosis. The dynamics of these three signaling processes and their interdependence in fibroblast cells are not clearly known to date. A systems biology model is proposed using reaction-diffusion equations for calcium, [Formula: see text], and calcium-dependent NO synthesis in fibroblast cells. The finite element method (FEM) is used to examine [Formula: see text], [Formula: see text], and NO regulation and dysregulation in cells. The results throw light on the conditions that disturb the coupled [Formula: see text] and [Formula: see text] dynamics and the influence of these factors on the levels of NO concentration in the fibroblast cell. The findings suggest that changes in source inflow, buffers, and diffusion coefficient might induce an increase or reduction in nitric oxide and [Formula: see text] synthesis, resulting in fibroblast cell diseases. Furthermore, the findings provide new information regarding the size and intensity of diseases in response to changes in several factors of their dynamics, which has been linked to the development of cystic fibrosis and cancer. This knowledge could be valuable for developing novel approaches to the diagnosis of diseases and therapies for various disorders of fibroblast cells.