Large Cavities Research Articles

Post-Operative Stereotactic Radiotherapy for Resected Brain Metastases: Results of the Multicenter Analysis (AURORA) of the German Working Group "Stereotactic Radiotherapy"

While the results of prospective studies support the use of postoperative stereotactic radiotherapy (RT) to the resection cavity (RC) as the standard of care after surgery, there are several issues that need to be investigated such as factors for improving local control, risk of leptomeningeal disease and radiation necrosis. Further, the optimal dose and fractionation is still under debate. The working group "Stereotactic Radiotherapy" of the German Society of Radiation Oncology (DEGRO) analyzed its multi-institutional database with 661 patients who received postoperative stereotactic RT to the RC. Treatment was performed at 13 centers between 2008 and 2021. Patient characteristics, treatment details, and follow-up data including overall survival (OS), local control (LC) were evaluated. Cox Regression and Kaplan-Meier curves with Log-rank Tests were calculated for selected variables. In this retrospective study, overall survival was 61.5% at 1 year, 47.6% at 2 years, and 35.5% at 3 years, and local control was 84.6% at 1 year, 74.8% at 2 years, and 72.8% at 3 years. 96% of patients were treated with hypofractionated stereotactic radiotherapy (HSRT), only 26 patients received single fraction radiosurgery (4%). Prognostic factors associated with overall survival were Karnofsky Performance Status, RPA and GPA class, controlled primary tumor and absence of extracranial metastases, whereas prognostic factor associated with local control was planning target volume (23 mL or less). HSRT is the most common fractionation form in the treatment of RCs in this multicenter analysis. This approach results in excellent OS and LC outcomes. OS in patients with resected brain metastases is mainly influenced by performance status. In regard to local control, RT of large cavities remain a challenge with significantly worse outcome.

Hitchhiker planting: mixed-species container stock planting as a novel tool to increase plant diversity on industrially disturbed sites

Rapid establishment of closed canopy cover is a key goal in land reclamation. While re-establishment of understory vegetation is likely to positively contribute to this goal, native herbaceous species are not typically planted on reclaimed sites though it is an alternative to reliance on natural regeneration. The objective of the present study was to test the principle of hitchhiker production of a tree species with native herbaceous species on recently reclaimed industrial sites with the aim of (1) understanding growth tradeoffs when mixing these species in the same container and (2) if hitchhiking had negative growth and survival outcomes for white spruce ( Picea glauca) seedlings compared with singly grown white spruce seedlings. White spruce seeds were sown in nursery containers of contrasting cavity sizes, followed by sowing a forb species ( Eurybia conspicua or Chamerion angustifolium) at different time intervals or grown singly. Larger cavities and earlier sow dates were associated with higher persistence and growth of the forbs, while later sow dates were associated with larger white spruce seedlings. We observed no evidence to suggest that hitchhiked seedlings were at a competitive disadvantage in terms of growth or survival compared with singly grown seedlings that were initially similar in size.

Neuroprotective effect and mechanism of cPLA2 inhibitor increases autophagic flux on spinal cord injury

To investigate the mechanism of cytosolic phospholipase A2(cPLA2) inhibitor to improve neurological function after spinal cord injury (SCI). Thirty-six 3 months old female SD rats, with body mass (280±20) g, were divided into three groups (n=12):sham group, SCI group, and SCI+ arachidonyl trifluoromethyl ketone(AACOCF3) group. Balloon compression SCI model was established in all three groups. In the sham model group, the spinal cord compression model was created after the balloon was placed without pressure treatment, and the remaining two groups were pressurized with the balloon for 48 h. After successful modeling, rats in the SCI+AACOCF3 group were injected intraperitoneally with AACOCF3, a specific inhibitor of cPLA2. The remaining two groups of rats were injected intraperitoneally with saline. The animals were sacrificed in batches on 7 and 14 days after modeling, respectively. And the damaged spinal cord tissues were sampled for pathomorphological observation, to detect the expression of cPLA2 and various autophagic fluxPrelated molecules and test the recovery of motor function. Spinal cord histomorphometry examination showed that the spinal cord tissue in the sham group was structurally intact, with normal numbers and morphology of neurons and glial cells. In the SCI group, spinal cord tissue fractures with large and prominent spinal cord cavities were seen. In the SCI+AACOCF3 group, the spinal cord tissue was more intact than in the SCI group, with more fused spinal cord cavities, more surviving neurons, and less glial cell hyperplasia. Western blot showed that the sham group had the lowest protein expression of LC3-Ⅱ, Beclin 1, p62, and cPLA2 compared with the SCI and SCI+AACOCF3 groups (P<0.05) and the highest protein expression of LC3-Ⅰ (P<0.05). P62 and cPLA2 expression in the SCI group were higher than in the SCI+AACOCF3 group (P<0.05). Behavioral observations showed that the time corresponding to BBB exercise scores was significantly lower in both the SCI and SCI+AACOCF3 groups than in the sham group (P<0.05). Scores at 3, 7, and 14 days after pressurization were higher in the SCI+AACOCF3 group than in the SCI group (P<0.05). cPLA2 inhibitors can reduce neuronal damage secondary to SCI, promote neurological recovery and improve motor function by improving lysosomal membrane permeability and regulating autophagic flux.

Exploring novel coral reef-like RuO2 oxides: Synthesis and physicochemical characterizations of gatifloxacin-based Ru(III) complexes

ABSTRACT. Two mixed-ligand complexes of Ru(III) ions were synthesized and used to generate nanostructured RuO2 oxide. Complex A contains gatifloxacin (L1), the amino acid glycine (L2), and Ru(III) ions in a 1:1:1 ratio. Complex B contains gatifloxacin (L1), the amino acid alanine (L3), and Ru(III) ions in a 1:1:1 ratio. The synthesized complexes were characterized using UV-Visible and IR spectroscopies, molar conductance, elemental analyses, thermogravimetry, XRD, and SEM-EDX techniques. In both complexes, the L1 ligand acts as a bidentate and uses the nitrogen atoms of the piperazine ring to capture the Ru(III) ions, while the L2 and L3 ligands capture the Ru(III) ions using their oxygen atom of the carboxylate group and the nitrogen atom of the amino group. The atmosphere around the Ru(III) ion is octahedral, and the complexes were formulated as [RuL1L2(H2O)2]Cl2 and [RuL1L3(H2O)2]Cl2 for Complex A and Complex B, respectively. Complex A was directly decomposed in air at 600 °C for 3 h to produce RuO2 oxide (Oxide A), and complex B was decomposed under the same conditions to produce RuO2 oxide (Oxide B). Morphologically, oxide A and oxide B have a coral reef-like texture with large holes and cavities.&#x0D; KEY WORDS: Gatifloxacin, Ru(III) ion, Glycine, Alanine, Morphology, RuO2 oxide&#x0D; Bull. Chem. Soc. Ethiop. 2023, 37(6), 1443-1457. DOI: https://dx.doi.org/10.4314/bcse.v37i6.12

Non-invasive investigations of closed landfills: An example in a karstic area

The monitoring of existing landfills is a pending environmental issue for the years to come. This monitoring is particularly challenging in the more and more common case of closed landfills, where direct investigation is difficult or impossible, calling for non-invasive methods, which in turn are stretched to maximizing their imaging capabilities in front of difficult logistical constraints, requiring novel and well-conceived scientific approaches. In this study we present a non-invasive approach designed and calibrated to identify the state of the subsoil underlying a closed urban waste landfill. In the presented case, two main questions had to be addressed: (a) whether large karstic cavities are present under the landfill, and (b) if any leachate leakage is present. A 3D Electrical Resistivity Tomography (ERT) configuration was used to solve the problem. The survey design has made use of forward model simulations, in order to verify whether the proposed approach was capable of imaging the possible large karstic cavities. This preliminary study showed the importance of choosing a suitable measurement protocol to recover the true position of the cavities. The analysis of the real field data did not show any anomaly compatible with the presence of large cavities, and thus, in comparison with the previous simulations, led to the conclusion that such cavities are not present. However, the results showed the presence of an electrically conductive anomaly, potentially be linked to leachate release. Direct investigations (drilling and sampling) confirmed the presence of fresh water in a silty sediment environment, both contributing towards the observed larger electrical conductivity, larger than the surrounding drier limestone bedrock. The presented general approach proved to be a valuable, generalizable, tool towards for the characterization and monitoring of closed landfills.

Experimental study of a 3D-printing technique combined with biphasic calcium phosphates to treat osteonecrosis of the femoral head in a canine model

ObjectiveThis study was aimed to use a digital design of 3D-printing technology to create a surgical navigation template. At the same time, biphasic calcium phosphate (BCP) was applied to treat osteonecrosis of the femoral head (ONFH) in animal models, based on accurate positioning of necrotic lesions in the navigation templates and observation of its therapeutic effect.MethodsFifteen healthy adult male and female beagle dogs weighing 20 + 2 kg were randomly divided into three groups (n = 5) after establishing a model of ONFH using the liquid nitrogen freezing method. Each model underwent necrotic lesion creation and BPC implantations on one side of the femoral head and only necrotic lesion creation on the other side of the femoral head. Each group underwent CT examination, gross observation, histological examination and immunohistochemical staining at 6 weeks, 12 weeks and 18 weeks postoperatively.ResultsAt weeks 6, 12, and 18, CT and gross examination showed that the necrotic area in the experimental group was basically intact and had been completely raised by BCP material. In the control group, there were signs of bone repair in the femoral head, but there were still large bone defects and cavities. At week 18, extensive collapse of the cartilage surface was observed. Through histological examination, in the experimental group at 12 and 18 weeks, a large number of new and reconstructed bone trabeculae containing a large amount of collagen fibres were observed (P < 0.05), while in the control group, there was extensive necrosis of the bone trabeculae without cellular structural areas. Immunohistochemical examination observation: A large number of CD31-positive cells were observed in the experimental group at 6 weeks, gradually decreasing at 12 and 18 weeks (P < 0.05), while a small number of CD31-positive cells were observed in the control group at 18 weeks.ConclusionThe 3D-printed navigation template can accurately locate ONFH lesions. Implantation of BCP material can effectively play a supporting role, prevent the collapse of the loading surface, and induce bone formation and angiogenesis to some extent.

Uniform Li-ion diffusion and robust solid electrolyte interface construction for kilogram-scale Si@ZIF powder as the anode in Li-ion batteries

The zeolitic imidazolate framework (ZIF) is characterized by a highly ordered structure, large cavities, and thermal/chemical stabilities and has been widely researched for energy storage. In this study, using commercial Si powder with a diameter of 50–200 nm at a kilogram scale, Si@ZIF core-shell particles with dispersed ZIF-8 rhombic dodecahedrons were fabricated by a one-pot method and achieved excellent electrochemical performance. With the specific pore diameter and ordered network formed by membered rings, experimental results demonstrated that the ZIF-8 shell realized a uniform and accelerated Li+ diffusion route, alleviated volumetric expansion of the Si core, and constructed a LiF-concentrated robust solid electrolyte interface film with less unnecessary consumption of electrolyte and Li+. Density functional theory calculations verified the higher adsorption energy for Li-solvated clusters and the de-solvation effect on the surface of ZIF-8, which can increase Li+ concentration along the one-dimensional channels of 4-membered ring with a diameter similar to that of Li+ for high-speed and uniform Li+ intercalation. Furthermore, the large and elastic rhombic dodecahedrons formed by pure ZIF-8 buffered the volume change and maintained the integrity of the Si electrode during cycling. As a result, the Si@8Z anode achieved a reversible capacity of 818.5 mAh g−1 after 650 cycles at 1 A g−1 with a high initial coulombic efficiency of 88.2 % and outstanding rater performance even at 8 A g−1. Nevertheless, the capacity of the Si anode decreased to 0 mAh g−1 after 200 cycles. The present work clarifies the effect of ZIF on the performance of Si anodes and provides a simple method to modify commercial Si powder.

Assessment of cavitation erosion risk by Eulerian–Lagrangian multiscale modeling

Cavitation erosion in fluid machineries is a complicated physicochemical and instantaneous process, leading to material loss and reduced efficiency. As the cavitation and the consequent erosion are difficult to be measured and modeled, the present work aims to incorporate an improved energy balance approach into a new Eulerian–Lagrangian multiscale model for addressing the risk of cavitation erosion. The volume of fluid (VOF) and discrete bubble model (DBM) are coupled by a transforming algorithm to develop the multiscale cavitation model. With using the large eddy simulation (LES) approach, the multiscale cavitation features including the morphological evolution of large-cavities and characteristics of microbubbles are well reproduced. To assess the cavitation erosion, a modified aggressive indicator using a modified moving time-averaged pressure field as the driving pressure is proposed to consider the evolution of local pressure and vapor volume fraction. Furthermore, the erosion powers produced from large cavities and microbubbles are completely taken into account. The results show that the VOF-DBM multiscale model can better simulate the cavitation features around a twisted hydrofoil including the secondary shedding and the horse-shoe vapor structure, compared with the VOF method using the same mesh resolution. From the results of discrete bubbles, it is found that the primary shedding leads to the rapid growth of the number of discrete bubbles, which decreases during the transportation of the bubble cloud generated from the primary shedding. By taking the collapsing power of discrete bubbles into account, the prediction of cavitation erosion distribution is quite consistent with the experimental one, whereas the VOF method fails to predict the erosion region near the trailing edge.

Nesting-tree preferences of the black woodpecker—the biggest cavity excavator in a conifer-dominated forests in Poland

The black woodpecker Dryocopus martius is an ecologically disproportionately important forest species owing to its abundance. Its large cavities provide breeding sites and shelter for many species—large birds, mammals, and social insects. I evaluated the nest tree preferences of black woodpeckers in the Augustów Forest, northeast Poland. Approximately 400 black woodpecker cavities were observed. The Scots pine, Pinus sylvestris, was the most commonly selected tree species, accounting for 90%. The cavity trees were 55–225 years old. All trees younger than 90 years were broadleaved tree species. The trees used to excavate the cavities had a larger diameter at the breast height (DBH) than the average of the stand. The trees selected by black woodpeckers were significantly shorter than the average height of the stands. Over 60% of the cavities were excavated 10–16 m above ground level. I found that the DBH and the first branch height were critical factors affecting the cavity entrance height. In pine-dominated forests, black woodpeckers preferred dead trees. Approximately 44% of new cavities were excavated from dead trees. Leaving dead or dying large trees in commercial forests benefits black woodpeckers and large secondary cavity nesters that depend on it and promotes biodiversity conservation. Birds excavate new cavities at a high rate yearly, in contrast with beech-dominated forests.

Combined Experimental and Mechanoelastic Modeling Studies on the Low-Spin Stabilized Mixed Crystals of 3D Oxalate-Based Coordination Materials.

Structural studies involving single-crystal and powder X-ray diffraction analysis have been performed on dehydrated coordination networks of the [NixCo1-x(bpy)3][LiCr(ox)3] series, 0 ≤ x ≤ 1, (bpy = 2,2'-bipyridine). The high-symmetry cubic 3D structure of these materials is formed by oxalate anions bridging alternating Cr3+ and Li+ ions into an anionic framework, which contains large cavities that incorporate the [NixCo1-x(bpy)3]2+ cations. Irrespective of the Co/Ni ratio, all of the mixed samples are phase-pure and retain the high-symmetry cubic structure, with the lattice parameters gradually decreasing upon increasing Ni(II) concentration. The influence of the Ni(II) dilution on the magnetic behavior of these materials is substantial. For pure [Co(bpy)3][LiCr(ox)3], a gradual but incomplete thermal spin-crossover is evident due to the effect of the chemical pressure applied by the [LiCr(ox)3]2- framework, which stabilizes the low-spin (LS) 2E state relative to the high-spin (HS) 4T1 state of the Co(II) ion. Upon increasing the Ni(II) content, the spin-crossover becomes even more gradual and incomplete and eventually is not observed for pure [Ni(bpy)3][LiCr(ox)3]. The average spin-crossover temperature increases with the increasing Ni(II) content, suggesting a higher degree of chemical pressure applied by the oxalate framework manifested by changing the ΔE0HL toward positive values. The magnetic behavior of all these framework materials has been explained by the mechanoelastic model, considering different radii for Co and Ni molecules and different interactions between Co-Co sites and Co-Ni sites. The model reproduced the incomplete transition, with the HS residual fraction at 300 K decreasing with increasing Ni concentration, and provided microscopic snapshots of the systems, showing how the existence of impurities prevented the spreading of Co atoms in the HS state.

Nest‐site selection and reproductive success of a critically endangered parrot, the Great Green Macaw (Ara ambiguus), in an anthropogenic landscape

Nest‐site selection is the principal way in which secondary cavity‐nesting species mitigate the negative effects of factors such as predation, parasitism and exposure on reproductive success. Large‐bodied secondary cavity‐nesting birds rely on large cavities in mature trees that are often absent or reduced in anthropogenically disturbed forests. Hence, the availability of high‐quality nest‐sites may be limited for these species, potentially reducing reproductive success. The aim of this study was to investigate nest‐site selection and the effect of nest‐site features on reproductive success in the critically endangered Great Green Macaw Ara ambiguus in northern Costa Rica. We show that Great Green Macaws select nest‐sites according to the characteristics of the cavity and the tree in which they are located. Moreover, reproductive success is a function of certain cavity features. However, the availability of high‐quality cavities, those with features associated with higher reproductive success, is potentially limited. By studying nest‐site selection and productivity together, we have identified that the availability of high‐quality cavities could potentially limit the future recovery of the critically endangered Great Green Macaw.

The significance of large old trees and tree cavities for forest carbon estimates

Large old trees have declined worldwide, even though they play a prominent role in biodiversity and also in carbon stocks of forests. We were interested in the contribution of large old trees to aboveground stand biomass and the role of wood decay inside the trunk and tree cavities for biomass and thus organic carbon stocks. We investigated this question using the example of old-growth oak forests, since oak is the tree species with the highest proportion of large old trees in Germany. Although we studied oak stands with a strongly above-average proportion of large old trees (with an aboveground biomass of 563 Mg ha−1), internal stem decay and tree cavities resulted in only about 1% overestimation of stand biomass. This was determined by subtracting biomass losses from internal stem decay from conventional biomass estimates derived from allometric regression. The extent of internal stem decay was measured using sonic tomography. Internal stem decay is thus negligible for stock density, but should be considered for continent-wide or global analyses where even small percentages add to large absolute errors. If trees of a stem diameter ≥ 7 cm were included in the analysis, the 11% largest trees of the stands accounted for 50% of the aboveground biomass. This result differs from recently published values of a global analysis suggesting that the 1% largest trees represent 50% of the stand biomass, but this difference is influenced by the minimum diameter at which young trees are included in the analysis. We suggest excluding young growth with diameters so small that their biomass does not significantly affect stand biomass from such analyses.

Dynamics of a confined pipe aspirating fluid concurrently subjected to external axial flow: Experiments on confinement length effects

The system under consideration comprises a flexible pipe and a coaxial rigid outer tube; the pipe and tube are vertically cantilevered from their top ends in a large fluid-filled cylindrical tank. The space between the pipe and tube forms an annulus around the upper portion of the pipe. The working fluid is water. The fluid enters the annulus from its top end with flow velocity Uo and is discharged from its bottom end; the fluid exits from the tank by flowing upwards in the pipe with velocity Ui.This flow configuration represents an idealized model of one of the modi operandi of ‘salt-mined caverns’, which are large underground cavities created to store hydrocarbons, such as natural gas and oil, in large quantities. At sufficiently high flow velocities the central pipe, referred to as the ‘brine-string’, vibrates, and may impact on the rigid cemented casing around it; sometimes this impact results in damage or breakage of the brine-string.Numerous experiments were performed in a laboratory-scale apparatus for several flow velocity ratios Uo/Ui, ranging from 0.02 to 0.40 (approx.), for three different outer tubes, 300, 200 and 100 mm in length; an elastomer flexible pipe approximately 441 mm long, was used in this study throughout. In all these experiments, the pipe loses stability via first-mode flutter at a sufficiently high flow velocity Ui, and at relatively lower Ui with increasing flow velocity ratio Uo/Ui and outer tube length L′. For the 300 mm outer tube, a dynamical behaviour similar to that for 200 mm outer tube, comprising two different dynamical features referred to as low and high flow velocity ratio behaviours, was observed. Also, a limit cycle was observed in the experiments for the first time, for the system involving a pipe aspirating fluid. For the 100 mm outer tube, however, only the high flow velocity ratio dynamical behaviour was observed. Finally, the effect of varying the outer tube length L′ on the foregoing dynamics is presented by comparing the experimental results for all three outer tube lengths, L′=100, 200 and 300 mm.

Effects of Different Types of Stabilizers on the Properties of Foam Detergent Used for Radioactive Surface Contamination.

Compared with high-pressure water and reagent washing decontamination, foam decontamination has a promising application due to its ability to significantly reduce the volume of radioactive waste liquids and effectively decontaminate the inner surface of the pipes, the interior of the large cavities, and the vertical walls. However, the foam is less stable, leading to a low decontamination rate. Currently, three main types of stabilizers with different stabilizing mechanisms, namely nanoparticles, polymers, and cosurfactants, are used to improve foam stability and thus increase the decontamination rate. Nanosilica (NS), xanthan gum (XG), and n-tetradecanol (TD) were used as typical representatives of nanoparticles, polymers, and cosurfactants, respectively, to improve the stability of the foam detergent with pH < 2 and chelating agents. The differences in the effects of these three types of stabilizers on foam properties were investigated. Although NS, XG, and TD all increase the half-life of the foam from 7.2 min to about 40 min, the concentration of TD is much lower than that of NS and XG in the foaming solution, and TD foaming solution has the highest foaming ratio. Moreover, TD can markedly lower the surface tension, resulting in a significant reduction of the wetting contact angle on the surfaces of glass, ceramic tile, stainless steel, and paint, while NS and XG cannot signally change the surface tension and have no obvious effect on the wetting contact angle. At low shear rates, TD can increase the apparent viscosity of foam by two orders of magnitude, and the wall-hanging time of the foam on the vertical wall is more than 30 min. In contrast, NS and XG cause a limited increase in the apparent viscosity of the foam, and the wall-hanging times are both less than 5 min. In addition, TD foaming solution has excellent storage stability, and the storage time has no obvious effect on the performance of the foam. And after only three days of storage, NS undergoes severe agglomeration and precipitation in the foaming solution, resulting in a complete loss of the stabilizing effect. After 90 days of storage, the half-life of XG foam decreases by 26%. For simulated radioactive uranium contamination on both horizontal and vertical surfaces, TD can significantly improve the decontamination rate, especially for vertical surfaces, where TD can increase the single decontamination rate by more than 50%.

Fracture Resistance of Class II MOD Cavities Restored by Direct and Indirect Techniques and Different Materials Combination.

This study aimed to evaluate the fracture resistance of class II MOD cavities restored using different techniques and materials. Sixty extracted maxillary molars were selected and standardized class II MOD cavities were prepared using a custom-made paralleling device. The specimens were divided into four groups based on the restoration technique used: Group 1 (direct resin composite), Group 2 (short-fiber-reinforced composite resin), Group 3 (composite polyethylene fiber reinforcement), and Group 4 (CAD/CAM resin inlays). Fracture resistance was assessed for each group after thermocycling aging for 10,000 cycles. The mode of fracture was assigned to five types using Burke's classification. To compare the fracture force among the tested materials, a paired sample t-test was performed. The significance level for each test was set at p < 0.05. Significant differences in fracture resistance were observed among the different restoration techniques. CAD/CAM inlays (2166 ± 615 N), short-fiber-reinforced composite resin (2471 ± 761 N), and composite polyethylene fiber reinforcement (1923 ± 492 N) showed superior fracture resistance compared to the group restored with direct resin composite (1242 ± 436 N). The conventional resin composite group exhibited the lowest mean fracture resistance. The choice of restoration material plays a critical role in the clinical survival of large MOD cavities. CAD/CAM inlays and fiber-reinforced composites offer improved fracture resistance, which is essential for long-term success in extensive restorations.

A Comparative in vitro Investigation on the Impact of Fiber Insertion on Cuspal Deflection of Maxillary Premolars Restored with Various Types of Bulk Fill Direct Composite Restorations

Background: Polymerization shrinkage remains a significant disadvantage that makes the use of direct composite restorations difficult. Objective: To evaluate how well a fiber insert and multiple bulk-fill direct restorations worked on the cuspal deflection of MOD cavities in premolar teeth using a Dino-Lite digital microscope and computer software. Methods: In sixty fresh maxillary first premolars, large MOD cavities were created. Teeth were randomly divided into six groups of ten based on restorative materials. SonicFill®, Beautifil Bulk®, and Filtek® Bulk Fill posterior restoratives were used in groups A1, B1, and C1, whereas groups A2, B2, and C2 used the same bulk composite with E-glass fiber (UFM, Dentapreg). Under a digital microscope, the intercuspal distance between two reference points on the cusp tips was measured before preparation, after preparation, 15 minutes after finishing restorations, and one month following incubation. Results: There was a significant difference between the groups after 15 minutes of restoration, but no significant differences following cavity preparation or one month of incubation. CD values were considerably higher after 15 minutes of restoration in groups restored with bulk fill only. Beautifil Bulk Fill restorative resulted in greater cuspal deflection than the other groups. The CD values in each group were significantly higher 15 minutes after restoration compared to cavity preparation and a month of incubation. Conclusion: Using inserts, cuspal deflection in MOD cavities can be significantly minimized, and stress release usually occurs after water incubation.

Nanoarchitectonics of lithium ion pathways through pores in a carbon framework for improving the storage capability and reversibility of lithium metal anode

The utilization of lithium (Li) metal as an anode has attracted significant attention for high‐energy Li batteries. Unfortunately, uncontrollable Li dendrite cannot be avoided during Li plating and stripping. Much intensive research has been conducted to suppress the dendritic growth by confinement of metallic Li in host architectures. Recently, zeolitic imidazolate frameworks (ZIFs) with a porous features have been used to explore a new approach to storing the Li metal with the advantages of their structural and chemical stability, large surface areas, and large pore cavities. Herein, we investigate the storage capability of metallic Li in a porous carbon framework derived from ZIFs as a function of carbonization temperature. Diversities in pore volumes and channels, the degree of crystallinity, the amount of residual zinc (Zn) metal, and the electrical conductivity can all be controlled by temperature. We demonstrate that well‐connected pore channels and adequate electrical conductivity secure the Li‐ion pathways and that well‐distributed Zn clusters in porous carbon trigger the outward growth of metallic Li from inside the frameworks, resulting in a relatively low overpotential and long‐lasting cyclability. Our findings can provide practical insight into advanced electrode design for next‐generation Li metal batteries.

Yolk-Shell Structured ST@Al2 O3 Enables Functional PE Separator with Enhanced Lewis Acid Sites for High-Performance Lithium Metal Batteries.

Commercial polymer separators usually have limited porosity, poor electrolyte wettability, and poor thermal and mechanical stability, which can deteriorate the performance of battery, especially at high current densities. In this work, a functional polyethylene (PE) separator is prepared by surface engineering a layer of Ti-doped SiO2 @Al2 O3 particles (denoted as ST@Al2 O3 -PE) with strong Lewis acid property and uniform porous structure on one side of the PE separator. On the other hand, ST@Al2 O3 particles with abundant pore structures and large cavities can store a large amount of electrolyte, providing a shortened pathway for lithium-ion transport, and the Lewis acid sites and porous structure of the ST@Al2 O3 can tune Li plating/stripping behavior and stabilize the lithium metal anode. The ST@Al2 O3 -PE separators exhibit better ionic conductivity (5.55 mS cm-1 ) and larger lithium-ion transference number (0.62). At a current density of 1 mA cm-2 , Li/Li symmetric cells with ST@Al2 O3 -PE separator can be stably cycled for more than 400 h, and both lithium iron phosphate /Li cells and lithium cobaltate/Li cells with ST@Al2 O3 -PE separator have good cycling and rate performance. This work provides a new strategy for developing functional separators and promoting the application of lithium metal batteries.

Multi-scale characteristics investigation of sheet/cloud cavitation

Sheet and cloud cavitation involve the formation of large-scale cavities and microbubbles across a wide range of length scales. In this study, a two-way coupling Eulerian-Lagrangian algorithm was utilized to simulate the cavitating flow around a NACA66 hydrofoil at an incidence of 8 degrees and a cavitation number of 1.2. The large eddy simulation (LES) and volume of fraction (VOF) methods are used to capture the large scale vapor structures in Eulerian frame. Meanwhile, the discrete bubble model (DBM) and simplified Rayleigh-Plesset equation are implied to solve the dynamic of Lagrangian microbubbles smaller than local grid scale. The results indicate that large-scale cavities are periodically shed downstream, influenced alternatively by the re-entrant jet and shock wave mechanisms, resulting in periodic variations of both the number and Sauter mean diameter of microscale bubbles. During the quasi-periodic evolution process of sheet/cloud cavitation, the microbubbles scatter around the large scale cavities where have strong turbulence intensity and high vorticity, and the probability density function of discrete bubble diameter similarly conforms to Gamma distribution with the dominant bubble size between 30 and 70μm. During the growth of an attached cavity, the number density of bubbles follows a power-law scaling with a value of -5/3 on radius. For the other stages, the bubble size spectrum of smaller microbubbles exhibits a -2/3 power-law scaling when the diameter of the microbubble is less than 200 μm. For larger bubbles with a diameter greater than 300 μm, the bubble density is proportional to the bubble radius to the power of -6.

Investigating the performance of the modified two-component pressure approach in capturing column separation with large vapour cavities

This paper investigates the performance of the modified two-component pressure approach (proposed model), recently proposed by the authors, in capturing column separation with large vapour cavities. The proposed model calculates both the cavitating and waterhammer flow regions using a single set of equations that governs unsteady flow in open channels. Comparing the results with experimental data, and the results obtained from the discrete gas cavity model (counterpart model) reveals that: (1) the proposed model can accurately capture the evolution of large vapour cavities in pipe systems; (2) the model provides more accurate results compared to the counterpart model; (3) under some circumstances the counterpart provides inaccurate results as it fails to account for the energy loss in the cavitating flow zone while the proposed model was shown to resolve the issue. Finally, the results exhibit the superiority of the proposed model over the counterpart model and the conventional open-channel-based models.