Internal Volume Research Articles

Experimental investigation on pressure drop characteristics of adiabatic two-phase flow in a Gyroid-structured channel

Recent advancements in additive manufacturing techniques have enabled the fabrication of intricate structures. Among these structures, triply periodic minimal surfaces (TPMSs) such as the gyroid, are particularly promising for heat and mass transfer applications owing to their higher surface area to volume ratios compared to conventional structures such as heat exchangers. This study experimentally investigates the pressure drop characteristics of single- and two-phase flows in a gyroid-structured channel under adiabatic conditions. In particular, using an additively manufactured test section with a gyroid-structured channel, the pressure drop characteristics of both single- and two-phase flows are analyzed. The results ofsingle-phase flow experiments reveal that the friction factor depends on the hydraulic diameter, which is defined by the internal volume and surface area of the channel. This suggests that in addition to the hydraulic diameter, other parameters such as porosity and wall thickness must also be considered. Subsequently, the two-phase pressure drop predictions of homogeneous and separated models are compared with the pressure drop data obtained from two-phase flow experiments. The results reveal that gas–liquid separation must be considered to accurately predict the pressure drop in regions influenced by gravitational effects. Furthermore, correlations for predicting the pressure drops both single- and two-phase flows within the operating constraints are proposed.

Enhancing the Experimental Performance of Axially Rotating Wickless Heat Pipe Using Annular- and Longitudinally Finned Condensers

Abstract This paper investigates the impact of longitudinal- and annular-finned condensers on the steady-state thermal performance of a horizontally rotating wickless heat pipe. The parameters investigated include two fin types (longitudinal and annular) for different numbers of longitudinal (6, 12, and 18) and annular fins (15, 30, and 45) at a constant rotating speed of 1500 rpm and heat fluxes from 2090 to 16,700 W/m2. A heat pipe was designed, constructed, and commissioned with seven condenser sections. The heat pipe is charged with water as a working fluid, filling 35% of the internal pipe volume. The results indicated that fins significantly enhance the performance of the rotating heat pipe. The longitudinally finned condenser with 18 fins achieved the highest performance among the condenser configurations. Specifically, at a heat flux of 2090 W/m2, the temperature difference between the condenser and evaporator decreased by 71.2% compared to the plain condenser. Additionally, the effective thermal conductivity of the heat pipe exhibits a remarkable enhancement of 3.47 times over the plain heat pipe at the same heat flux. This enhancement highlights a substantial effect of the longitudinally finned condenser on the axially rotating heat pipe performance.

Impact of interplay effects on spot scanning proton therapy with motion mitigation techniques for lung cancer: SFUD versus robustly optimized IMPT plans utilizing a four-dimensional dynamic dose simulation tool

BackgroundThe interaction between breathing motion and scanning beams causes interplay effects in spot-scanning proton therapy for lung cancer, resulting in compromised treatment quality. This study investigated the effects and clinical robustness of two types of spot-scanning proton therapy with motion-mitigation techniques for locally advanced non-small cell lung cancer (NSCLC) using a new simulation tool (4DCT-based dose reconstruction).MethodsThree-field single-field uniform dose (SFUD) and robustly optimized intensity-modulated proton therapy (IMPT) plans combined with gating and re-scanning techniques were created using a VQA treatment planning system for 15 patients with locally advanced NSCLC (70 GyRBE/35 fractions). In addition, gating windows of three or five phases around the end-of-expiration phase and two internal gross tumor volumes (iGTVs) were created, and a re-scanning number of four was used. First, the static dose (SD) was calculated using the end-of-expiration computed tomography (CT) images. The four-dimensional dynamic dose (4DDD) was then calculated using the SD plans, 4D-CT images, and the deformable image registration technique on end-of-expiration CT. The target coverage (V98%, V100%), homogeneity index (HI), and conformation number (CN) for the iGTVs and organ-at-risk (OAR) doses were calculated for the SD and 4DDD groups and statistically compared between the SD, 4DDD, SFUD, and IMPT treatment plans using paired t-test.ResultsIn the 3- and 5-phase SFUD, statistically significant differences between the SD and 4DDD groups were observed for V100%, HI, and CN. In addition, statistically significant differences were observed for V98%, V100%, and HI in phases 3 and 5 of IMPT. The mean V98% and V100% in both 3-phase plans were within clinical limits (> 95%) when interplay effects were considered; however, V100% decreased to 89.3% and 94.0% for the 5-phase SFUD and IMPT, respectively. Regarding the significant differences in the deterioration rates of the dose volume histogram (DVH) indices, the 3-phase SFUD plans had lower V98% and CN values and higher V100% values than the IMPT plans. In the 5-phase plans, SFUD had higher deterioration rates for V100% and HI than IMPT.ConclusionsInterplay effects minimally impacted target coverage and OAR doses in SFUD and robustly optimized IMPT with 3-phase gating and re-scanning for locally advanced NSCLC. However, target coverage significantly declined with an increased gating window. Robustly optimized IMPT showed superior resilience to interplay effects, ensuring better target coverage, prescription dose adherence, and homogeneity than SFUD.Trial registration: None.

A lung SBRT treatment planning technique to focus high dose on gross disease

This study investigated a straightforward treatment planning technique for definitive stereotactic body radiation therapy (SBRT) for patients with early-stage lung cancer aimed at increasing dose to gross disease by strategically penalizing the normal tissue objective (NTO) in the EclipseTM treatment planning system. Twenty-five SBRT cases were replanned to 50 Gy in 5 fractions using static and dynamic NTO methods (50 plans total). The NTO had a start dose of 100% at the target border, end dose of 20%, fall-off rate of 0.4/mm, and a priority of 150. For the static NTO plans, a lower planning target volume (PTV) objective was placed at 52 Gy with a priority of 100. Maximum dose was not penalized. Optimization was performed without user interaction. In contrast, the planner incrementally increased the priority of the NTO on the dynamic NTO plans until 95% of the target volume was covered by the prescription dose. Further, the dynamic NTO plans used both PTV lower and upper objectives at 63-64 Gy with priorities of 50. Maximum dose was penalized to ensure that the hot spot was within ± 2% of the static NTO global maximum dose. Following optimization, all plans were normalized so that the prescription dose covered 95% of the PTV. Plans were scored based on RTOG 0813 criteria, and dose to the internal target volume (ITV) and PTV was evaluated. The Wilcoxon signed-rank test (threshold = 0.05) was used to evaluate differences between the static and dynamic NTO plans. All plans met RTOG 0813 planning guidelines. In comparison to the static NTO plans, the dynamic NTO plans exhibited statistically significant increases in PTV mean dose, ITV mean dose, and PTV-ITV mean dose. Notably, the dynamic NTO plans more effectively concentrated the high dose on gross disease at the center of the PTV. As compared to the static NTO plans, the mean dose was 4.6 Gy higher in the ITV while only 1.3 Gy higher in the PTV-ITV rind of the dynamic NTO plans. Global maximum doses were similar. There were some small yet statistically significant differences in dose conformity between plan types. Furthermore, the dynamic NTO plans demonstrated a significant reduction in total monitor units (MU). This study demonstrated an efficient optimization strategy for lung SBRT plans that concentrates the highest dose in the gross disease, which may improve local control.

The Current use of Adaptive Strategies for External Beam Radiotherapy in Cervical Cancer: A Systematic Review

AimsVariability in the target and organs at risk (OARs) in cervical cancer treatment presents challenges for precise radiotherapy. Adaptive radiotherapy (ART) offers the potential to enhance treatment precision and outcomes. However, the increased workload and a lack of consensus on the most suitable ART approach hinder its clinical adoption. This systematic review aims to assess the current use of adaptive strategies for cervical cancer and define the optimal approach. Materials and methodsA systematic review of current literature published between January 2012 and May 2023 was conducted. Searches used PubMed/Medline, Cochrane Library, and Web of Science databases, supplemented with the University of Manchester, Google Scholar, and papers retrieved from reference lists. The review assessed workflows, compared dosimetric benefits, and examined resources for each identified strategy. Excluded were abstracts, conference abstracts, reviews, articles unrelated to ART management, proton therapy, brachytherapy, or qualitative studies. A narrative synthesis involved data tabulation, summarizing selected studies detailing workflow for cervical cancer and dosimetric outcomes for targets and OARs. ResultsSixteen articles met the inclusion criteria; these were mostly retrospective simulation planning studies, except four studies that had been clinically implemented. We identified five approaches for ART radiotherapy for cervical cancer: reactive and scheduled adaptation, internal target volume (ITV)-based approach using library of plans (LOP), fixed-margin approach using LOP, and real-time adaptation, with each approach reducing irradiated volumes without compromising target coverage compared to the non-ART approach. The LOP-based ITV approach is the most used and clinically assessed. ConclusionIdentifying the optimal strategy is challenging due to dosimetric assessment limitations. Implementing cervical cancer ART necessitates strategic optimization of clinical benefits and resources through research, including studies to identify the optimal frequency, and prospective evaluations of toxicity.

Heat‐resistant and transparent polyimides derived from alicyclic dianhydrides and phthalazinone‐based diamine

AbstractAdvanced flexible display materials have drastically sparked considerable interest for heat‐resistant, low dielectric, and transparent polyimide (PI) materials. In light of this, our study aims to develop high‐performance semi‐aromatic PI films, followed by investigate the correlations between bridged‐alkyl/heteroaromatic ring structures and their thermal, dielectric, optical, and mechanical properties. Such PI films, namely AP‐PIs, were synthesized with a one‐step high‐temperature method between 4‐[4‐(4‐aminophenoxy) phenyl]‐2‐(4‐aminophenyl)‐1(2H)‐phthalazinone (DHPZDA) and various commercial alicyclic dianhydrides. The incorporation of rigid phthalazinone structures significantly enhanced thermal resistance and mechanical flexibility, while simultaneously reducing their dielectric constant (Dk), attributed to the large polymer internal free volume. Impressively, the prepared films exhibit exceptional glass transition temperature (Tg) as high as 419°C (DMTA tanδ peak), low Dk as low as 2.71, and elongation at break (ε %) up to 50.4%. Furthermore, AP‐PI films demonstrate reasonable solubility and optical transparency within the UV–visible region. The maximum optical transmittance at 550 nm (T550 nm) could reach 83.01%. These desirable properties position these materials as promising candidates for flexible substrate applications.

Cryo-EM-based discovery of a pathogenic parvovirus causing epidemic mortality by black wasting disease in farmed beetles

We use cryoelectron microscopy (cryo-EM) as a sequence- and culture-independent diagnostic tool to identify the etiological agent of an agricultural pandemic. For the past 4 years, American insect-rearing facilities have experienced a distinctive larval pathology and colony collapse of farmed Zophobas morio (superworm). By means of cryo-EM, we discovered the causative agent: a densovirus that we named Zophobas morio black wasting virus (ZmBWV). We confirmed the etiology of disease by fulfilling Koch's postulates and characterizing strains from across the United States. ZmBWV is a member of the family Parvoviridae with a 5,542 nt genome, and we describe intersubunit interactions explaining its expanded internal volume relative to human parvoviruses. Cryo-EM structures at resolutions up to 2.1Å revealed single-strand DNA (ssDNA) ordering at the capsid inner surface pinned by base-binding pockets in the capsid inner surface. Also, we demonstrated the prophylactic potential of non-pathogenic strains to provide cross-protection invivo.

Impact of internal phase volume on the physical, morphological and mechanical characteristics of emulsion templated scaffolds

Objectives: The high porosity of tissue engineering scaffolds is advantageous as they provide a high degree of infiltration of nutrients, enable cell penetration, and support vascularisation. However, the mechanical strength is also critical for providing structural support to the defect site throughout the regeneration process. In this study, we aimed to establish a relationship between internal phase volume and emulsion-templated scaffolds' physical, morphological and mechanical characteristics. Methods: In this work, tetra methacrylate functionalised polycaprolactone (4PCLMA) polymers were synthesised via ring-opening polymerisation followed by methacrylation. 4PCLMA-based emulsion templated matrices with 60%, 75% and 82% internal phase volumes were fabricated (P60, P75, and P82). These scaffolds' densities, porosities, average pore and window sizes, degree of interconnectivity values, and mechanical properties were investigated. Results: Increasing internal phase volume reduced the density of the foams by almost two-fold. No direct correlation was observed between average pore size and internal phase volume. Both the average window sizes and the degree of interconnectivity values increase with increasing internal phase volume. Compression modulus values are calculated as 0.46±0.04 MPa, 0.23±0.02 MPa and 0.14±0.01 MPa for P60, P75, and P82, respectively. Increasing internal phase volume from 60% to 82% caused a more than 2-fold reduction in the stiffness of the emulsion-templated matrices. Conclusions: Accordingly, by reporting on this experimental framework, we established a relationship between internal phase volume and the physical, morphological and mechanical characteristics of 4PCMA-based scaffolds to precisely engineer these characteristics for specific tissue engineering applications.

Phenylseleninate-Connected Telluroxane Clusters.

Hydrolysis of PhTeI3 in the presence of sodium phenylseleninate and M3+ ions (M = Y, Nd, Ce) gives well-defined, bowl-shaped telluroxane clusters. Each of the two half-spheres of the compositions [(PhTe)18{ML}O24]7+/8+ ({ML} = {Y(NO3)(H2O)}2+ (1), {Nd(NO3)(H2O)2+} (2), or {Ce(NO3)2}+ (3)) are connected by two (compound 3) or four (compounds 1 and 2) PhSeO2- bridges. The resulting chalcogenoxane spheres have internal volumes of approximately 1500 Å3. Charge compensation is provided by nitrate ions and/or [Na2(NO3)8]6- clusters, which are located inside and surrounding these spheres.

Effects of coarse aggregates on 3D printability and mechanical properties of ultra high performance fiber reinforced concrete

3D printing of ultra high performance fiber reinforced concrete (UHPFRC) suffers from high shrinkage and poor interlayer properties. To mitigate these problems, this study develops new mixtures of UHPFRC materials containing coarse aggregates (CA), and critically examines their suitability for 3D printing (3DP). Totally 90 mould-cast and 3DP cylinder and beam specimens with different CA sizes (5–15 mm) and CA-binder ratios (0.3–0.5) were tested under compression and bending in three directions. The internal distribution and volume fractions of steel fibers and pores and the crack trajectories were characterized and analysed by micro X-ray CT scanned 3D images with 37 μm voxel resolution. The results show that adding more and bigger CAs into UHPFRC reduced the flowability but enhanced the buildability with desired extrudability achieved by adjusting 3D printing velocity. Although the compressive strength of the 3DP cylinders was 15–42 % lower than that of the mould-cast ones due to higher porosities, over 100 MPa strength was still achieved for all the 3DP cylinders with less than 10 % anisotropy. The CT images did not show evident interlayers and interlayer delamination under compression, indicating the new 3DP mixtures and printing parameters may have highly promoted cement hydration. The flexural strength of 3DP beams was 3–34 % higher than that of the cast ones, because most fibres were oriented in the printing or beam axis direction as represented by overall orientation indices calculated from CT images, thereby providing significant crack-bridging effects. The developed new mixtures are therefore well suited for 3D printing, particularly for fabrication of structural members with preferred fibre orientation, such as beams, slabs and shells.

An Improved Method to Calculate Gas-Lift Valve Set Pressure

Summary This study aims to enhance the accuracy of gas-lift valve (GLV) design set pressure calculations by incorporating the effects of silicone thermal expansion, silicone compression, and dome thermal expansion. The proposed method is compared with experimental measurements and current industry methods. The analysis includes an experimental assessment of the impact of internal dome volume changes on the design set pressure, considering various silicone fill levels, pressures, and temperatures. Experimental conditions cover silicone fills of 25%, 50%, and 75%, initial pressures from 975 psig to 1,250 psig, and temperatures from 60°F to 175°F. These conditions cover the conventional operating range in the industry. The results show that silicone expansion is the most dominant factor among silicone compression and chamber thermal expansion. The proposed method significantly improves GLV design set pressure calculations, especially for high-pressure and high-temperature conditions. The study suggests improvements in injection-pressure-operated (IPO) valve design practices to avoid multipoint injection and unloading failures. To the best of the authors’ knowledge, the impact of silicone expansion on GLV set pressure has not been investigated in the open literature. The enhanced method proposed in this research could significantly impact well unloading and production operations for wells equipped with GLVs. In addition, this work suggests an improvement on the American Petroleum Institute (API) recommended practice, especially when dealing with high-pressure, high-temperature wells and when utilizing refurbished GLVs.

Steric Hindrance Engineering to Modulate the Closed Pores Formation of Polymer‐Derived Hard Carbon for High‐Performance Sodium‐Ion Batteries

AbstractThe closed pores play a critical role in improving the sodium storage capacity of hard carbon (HC) anode, however, their formation mechanism as well as the efficient modulation strategy at molecular level in the polymer‐derived HCs is still lacking. In this work, the steric hindrance effect has been proposed to create closed pores in the polymer‐derived HCs for the first time through grafting the aromatic rings within and between the main chains in the precursor. The experimental data and theoretical calculation demonstrate that steric‐hindrance effect from the aromatic ring side group can increase backbone rigidity and the internal free volumes in the polymer precursor, which can prevent the over graphitization and facilitate the formation of closed pores during the carbonization process. As a result, the as‐prepared HC anode exhibits a remarkably enhanced discharge capacity of 340.3 mAh/g at 0.1 C, improved rate performance (210.7 mAh/g at 5 C) as well as boosted cycling stability (86.4 % over 1000 cycles at 2 C). This work provides a new insight into the formation mechanisms of closed pores via steric hindrance engineering, which can shed light on the development of high‐performance polymer‐derived HC anode for sodium‐ion batteries.

Comparative analysis of delivered and planned doses in target volumes for lung stereotactic ablative radiotherapy

BackgroundAdaptive therapy has been enormously improved based on the art of generating adaptive computed tomography (ACT) from planning CT (PCT) and the on-board image used for the patient setup. Exploiting the ACT, this study evaluated the dose delivered to patients with non-small-cell lung cancer (NSCLC) patients treated with stereotactic ablative radiotherapy (SABR) and derived relationship between the delivered dose and the parameters obtained through the evaluation procedure.MethodsSABR treatment records of 72 patients with NSCLC who were prescribed a dose of 60 Gy (Dprescribed) to the 95% volume of the planning target volume (PTV) in four fractions were analysed in this retrospective study; 288 ACTs were generated by rigid and deformable registration of a PCT to a cone-beam computed tomography (CBCT) per fraction. Each ACT was sent to the treatment planning system (TPS) and treated as an individual PCT to calculate the dose. Delivered dose to a patient was estimated by averaging four doses calculated from four ACTs per treatment. Through the process, each ACT provided the geometric parameters, such as mean displacement of the deformed PTV voxels (Warpmean) and Dice similarity coefficient (DSC) from deformation vector field, and dosimetric parameters, e.g. difference of homogeneity index (ΔHI, HI defined as (D2%-D98%)/Dprescribed*100) and mean delivered dose to the PTV (Dmean), obtained from the dose statistics in the TPS. Those parameters were analyzed using multiple linear regression and one-way-ANOVA of SPSS® (version 27).ResultsThe prescribed dose was confirmed to be fully delivered to internal target volume (ITV) within maximum difference of 1%, and the difference between the planned and delivered doses to the PTV was agreed within 6% for more than 95% of the ACT cases. Volume changes of the ITV during the treatment course were observed to be minor in comparison of their standard deviations. Multiple linear regression analysis between the obtained parameters and the dose delivered to 95% volume of the PTV (D95%) revealed four PTV parameters [Warpmean, DSC, ΔHI between the PCT and ACT, Dmean] and the PTV D95% to be significantly related with P-values < 0.05. The ACT cases of high ΔHI were caused by higher values of the Warpmean and DSC from the deformable image registration, resulting in lower PTV D95% delivered. The mean values of PTV D95% and Warpmean showed significant differences depending on the lung lobe where the tumour was located.ConclusionsEvaluation of the dose delivered to patients with NSCLC treated with SABR using ACTs confirmed that the prescribed dose was accurately delivered to the ITV. However, for the PTV, certain ACT cases characterised by high HI deviations from the original plan demonstrated variations in the delivered dose. These variations may potentially arise from factors such as patient setup during treatment, as suggested by the statistical analyses of the parameters obtained from the dose evaluation process.

Anchoring Metal-Nitrogen Sites on Porous Carbon Polyhedra with Highly Accessible Multichannels for Efficient Oxygen Reduction.

Transition metal-nitrogen-carbon complexes, featuring single metal atoms embedded in a nitrogen-doped carbon matrix, emerge as promising alternatives to traditional platinum-based catalysts, offering cost-effectiveness, abundance, and enhanced catalytic performance. This work introduces a novel method for the etching and doping of zeolitic imidazolate frameworks (ZIFs) with transition metals, creating a uniform distribution of secondary metal centers on ZIF surfaces. By disrupting the crystalline symmetry of ZIFs through synthetic defect engineering, we gain access to their entire internal volume, creating multichannel pathways. The absorption of metal ions is theoretically simulated, demonstrating their thermodynamically spontaneous nature. The selective removal of defect channels under Lewis acidic conditions, induced by metal ion alcoholysis/hydrolysis, facilitates the introduction of metal atoms into ZIF cavities. The resulting single-atom catalyst, after pyrolysis, features a three-dimensional (3D) multichannel structure, high surface area, and uniformly dispersed metal atoms within the N-doped carbon matrix, establishing it as an exceptional catalyst for the oxygen reduction reaction (ORR). Our findings highlight the potential of using metal etching in defect-engineered metal-organic frameworks (MOFs) for single-atom catalyst preparation, paving the way for the next generation of high-performance, cost-effective ORR catalysts in sustainable energy systems.

Evaluation of the impact of combustion chamber geometries for biomass plancha-type cookstoves

Improved cookstoves are used to reduce carbon emissions into the atmosphere and the impact of deforestation, thus improving the quality of life of their users. The main objective of this work is to evaluate three combustion chamber geometries for biomass plancha-type cookstoves, in the range of 9.5–12.5 kW, which corresponds to real operating conditions. The first geometry corresponds to a traditional rocket elbow section that is widely used in this kind of device. The other two geometries are new modified designs. They make use of three and four chamfers above the rocket elbow. Additionally, for all the geometries, the effect of a baffle close to the exit of the chimney is evaluated. Numerical simulations for fluid flow, heat transfer, and gas-phase chemical reactions for the three-dimensional internal volume of the geometries are conducted using ANSYS Fluent 2019 R3. Results for the average temperature on the comal and total mass flow rate at the exit of the chimney are validated with experimental measurements and a theoretical model, respectively. The main findings are that the use of a baffle in all geometries increases the flow recirculation below the comal; as a result, the average temperature of the comal and hence the thermal efficiency reach higher values. Based upon numerical predictions, the cookstove with three chamfers and a baffle provided a more temperature homogeneous distribution on the comal.

Anion exchange membrane incorporating polymers of intrinsic microporosity for large organic anions

To meet a growing demand for the applications of electro-membrane technologies in the fields related to organic acid, this work attempts to incorporate polymers of intrinsic microporosity (PIM) with rigid and twisted structure into the preparation of anion exchange membrane (AEM) and investigates the possible effects of PIM addition on the transport behaviors of bulky organic anions therein. Firstly, molecular dynamics simulations are conducted to optimize the blend ratio between the modified PIM and chloromethylated Polysulfone. Furthermore, performances of as-prepared AEMs with different blend ratios are evaluated in some typical organic salt systems, including sodium lactate, sodium gluconate, and sodium citrate. Results demonstrate that water uptake increases and electrical resistance decreases significantly with increasing PIM loading despite the moderate reductions in ion exchange capacities. For example, a reduction of >50 % in electrical resistance when the PIM fraction increases up to 20 %. Small angle X-ray scattering reveals that these changes appear to be the result of micro-phase separation and increase of internal free volume. Additionally, electrometathesis-based organic acid conversion experiments confirm that the blend AEMs indeed contribute to reduce process energy consumption, for instance, a reduction of up to 23.29 % for the gluconic acid conversion. Although the addition of PIM results in a loss of membrane permselectivity to some extent, the corresponding current efficiency is still acceptable. Incorporation of Polymers of Intrinsic Microporosity is worth exploring for the preparation of Bulky Organic Anions-oriented AEM.

A Four-dimensional Computed Tomography Generated Internal Target Volume Approach to Paediatric High Risk Neuroblastoma to Reduce Organ at Risk and Normal Tissue Irradiation

AimsThe magnitude of upper abdominal organ motion in children may be overestimated by current planning target volumes (PTV). A four-dimensional computed tomography (4DCT) – derived internal target volume (ITV) is frequently used in adult radiotherapy to take respiratory-related organ motion into account. In this study, the dosimetric consequences for target coverage and organs at risk from the use of an ITV approach compared to standard PTV margins in children with high-risk neuroblastoma were investigated. Materials and methods14 patients, median age 4.1 years, range 1.5 – 18.9 years, (9 midline targets, 5 lateralised) each had two dual arc volumetric modulated arc therapy (VMAT) plans (14 ×1.5 Gy) generated. One used an ITV-approach; motion information derived from 4DCT (PTV_itv) with a 5mm ITV to PTV expansion, and the other a PTV margin of 10mm from CTV to PTV (PTV_standard). Differences in absolute PTV volume and organ at risk doses are described. ResultsThe ITV approach resulted in a highly significant reduction in PTV size of 38% (p<0.0001). For midline targets, an ITV approach resulted in a small but statistically significant reduction in combined mean kidney dose of 0.8Gy, p 0.01. Mean heart and lung dose were reduced by an average of 1 Gy with an ITV approach. Non-PTV integral dose from 30.4 Gy L to 27.8 Gy L using an ITV approach. ConclusionAn ITV-approach to respiratory related organ motion management in children can significantly reduce absolute PTV volumes, maintain target coverage and reduce dose delivered to normal tissue in proximity to the target. This is an essential step to maximising the benefits of highly conformal radiotherapy techniques including VMAT for this patient group, and in the future with Proton Therapy.

Insight into the role of droplets in quinoa starch-based Pickering high internal phase emulsion for enzymatic hydrolysis reaction

Pickering high internal phase emulsion has emerged as potential platforms for biocatalytic reactions. Herein, native quinoa starch was used as the emulsifier to form a stable Pickering HIPE with an internal phase up to 80 %. The catalytic performance of lipase loaded in HIPE was evaluated for the enzymatic hydrolysis of hexyl hexanoate. Compared with the typical Pickering emulsion, biphasic, and monophasic systems, the Pickering HIPE system displayed higher conversion (83.54 % at 1440 min) and specific enzyme activity (1.41 U/mg), thus emphasizing the crucial role of microdroplets and large interface area created by both the starch particles and high internal phase volume. Subsequently, HIPEs with different starch concentrations were fabricated to further understand the catalysis behavior happening at compartmentalized microdroplets and interfaces. The microstructural, interfacial, and rheological properties of the HIPEs were systematically determined to explain the correlation between emulsion properties and catalytic efficiency. High starch concentration reduced the droplet size and increased the interfacial area, thus shortening the mass transfer distance and enlarging the reaction area. Meanwhile, the increased surface coverage and viscosity led to poor accessibility and limited mass movement. This trade-off made the maximum conversion be obtained at 2 wt% concentration. The study provides novel information about the role of emulsion droplets in the catalytic performance of lipase in starch-based HIPE.

Design optimization of cubic-shaped pressurant tank for CubeSat propulsion system

From a technical and economic point of view, cold gas propulsion for nanosatellites is one of the more rational systems. There is a problem, however: the optimal spherical shape for a high-pressure vessel only takes up half the cubic volume of the CubeSat unit. To increase the volume, it is proposed to switch to a cubic-shaped tank. The aim of this work is to synthesize the more rational structural design of a pressurant tank that fits within a cubic constraint, which provides the perfect balance between the mass of the structure and the delta-V budget available for the propulsion system. The proposed variants are as follows: a set of four cylinders with spherical bottoms; 14 equal spheres arranged in a face-centered cubic packing; a thin-walled cube supported by ribs, the location and parameters of which provide the smallest mass of the structure; a cube, the reinforcement scheme of which is calculated using topology optimization method; an original polyspheric and bypass design schemes where the filling of the volume of the cube is created by a set of spherical and cylindrical shells of different radii. All the considered vessel variants can be obtained using additive technologies, such as selective laser sintering. For each variant, the internal volume and mass of the vessels were obtained, as well as the delta-V budget, taking into account the mass of the tank and the mass of the stored gas. The analysis of the results reveals that there are two structures that are more rational. The new bypass scheme provides the largest delta-V budget, but it has a 1.6 times larger mass than the initial spherical vessel design. It should be noted that the difference in vessel mass is not crucial for CubeSat form factor satellites. Choosing a rational design may require a larger delta-V budget. The possibility of increasing the reserve delta-V of the CubeSat cold gas propulsion system by 25–35 % due to the transition from a spherical to a cube-shaped tank has been demonstrated. At the same time, the mass of the tank structure increases by 1.6–6.3 times, which can be considered an acceptable price for increasing the efficiency of the propulsion system. The new bypass scheme offers the optimal balance of mass and delta-V reserve.

Efficacy, safety and mechanism of Simiaoyongan decoction in the treatment of carotid atherosclerotic plaque: a randomized, double-blind, placebo-controlled clinical trial protocol

IntroductionChronic inflammation is the major pathological feature of Atherosclerosis(As). Inflammation may accelerate plaque to develop, which is a key factor resulting in the thinning of the fibrous cap and the vulnerable rupture of plaque. Presently, clinical treatments are still lacking. It is necessary to find a safe and effective treatment for As inflammation. Simiaoyongan Decoction (SMYA) has potential anti-inflammatory and plaque protection effects. This protocol aims to evaluate the efficacy, safety, and mechanism of SMYA for patients with carotid atherosclerotic plaque.Methods/designThe assessment of SMYA clinical trial is designed as a randomized, double-blind, placebo-controlled study. The sample size is 86 cases in total, with 43 participants in the intervention group and the control group respectively. The intervention group takes SMYA, while the control group takes SMYA placebo. The medication lasts for 14 days every 10 weeks, with a total of 50 weeks. We will use carotid artery high resolution magnetic resonance imaging (HR-MRI) to measure plaque. The plaque minimum fiber cap thickness (PMFCT) is adopted as the primary outcome. The secondary outcomes include plaque fiber cap volume, volume percentage of fiber cap, lipid-rich necrotic core (LRNC) volume, volume percentage of LRNC, internal bleeding volume of plaque, internal bleeding volume percentage of plaque, plaque calcification volume, volume percentage of plaque calcification, lumen stenosis rate, average and a maximum of vessel wall thickness, vessel wall volume, total vessel wall load, carotid atherosclerosis score, hs-CRP, IL-1β and IL-6, the level of lipid profiles and blood glucose, blood pressure, and body weight.DiscussionWe anticipate that patients with As plaque will be improved from SMYA by inhibiting inflammation to enhance plaque stability. This study analyzes plaque by using HR-MRI to evaluate the clinical efficacy and safety of SMYA. Moreover, we conduct transcriptome analysis, proteomic analysis, and metagenomic analysis of blood and stool of participants to study the mechanism of SMYA against As plaque. This is the first prospective TCM trial to observe and treat As plaque by inhibiting inflammatory reaction directly. If successful, the finding will be valuable in the treatment of As plaque and drug development, especially in the “statin era”.Trial registration numberThis trial is registered on Chinese Clinical Trials.gov with number ChiCTR2000039062 on October 15, 2020 (http://www.chictr.org.cn).