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Abstract Objective To evaluate the safety and efficacy of rigid ureteroscopic lithotripsy with a pressure-controlling ureteral access sheath (PC-UAS) for complex steinstrasse. Methods Thirty-one consecutive patients (male: 18; female: 13) with steinstrasse were enrolled, six of whom had concurrent kidney stones. The mean cumulative stone size was 2.7 ± 1.3 cm. The patients were treated with rigid ureteroscopic lithotripsy using a PC-UAS. The cavity pressure parameters were set as follows: control value at -15 mmHg to -2 mmHg, warning value at 20 mmHg, and limit value at 30 mmHg. The infusion flow rate was set at 150–200 ml/min. A holmium laser (550 μm) was used to powderize the stone at 2.0–2.5 J/pulse with a frequency of 20–30 pulses/s. Analyses included cavity pressure, operative time, stone-free rates, and complications. Results Among the 31 patients, 29 were successfully treated with PC-UAS, with nine requiring adjunctive flexible ureteroscopy for stone migration to the kidney. Two procedures were converted to percutaneous nephrolithotomies due to failure of sheath placement. The cavity pressure of all 29 patients was well-maintained below 20 mmHg, with clear vision. The mean operative time was 48.2 ± 17.7 min. No complications, such as ureteral perforation, mucosal avulsion, or hemorrhage, occurred. Two cases of Clavien-Dindo grade I complications occurred. No major complications (Clavien-Dindo grade II–V) occurred. The mean postoperative hospitalization time was 1.7 days. The stone-free rates 1 day and 1 month after surgery were 93.1% and 96.6%, respectively. One patient with residual stones underwent extracorporeal shockwaves. Conclusions Rigid ureteroscopic lithotripsy with PC-UAS can effectively control the cavity pressure, shorten the operation time, and improve the efficiency of broken stones, thus reducing the complication rate.

● Fortunella genus consists of two populations: cultivated kumquat and wild Hong Kong kumquat. ● Artificial selection might involve in the origin of cultivated Fortunella species. ● A hypothesis for the differentiation and speciation of Fortunella species is proposed. Kumquat (Fortunella spp.) is a fruit and ornamental crop worldwide due to the palatable taste and high ornamental value of its fruit. Although Fortunella is classified into the economically important true citrus fruit tree group together with Citrus and Poncirus, few studies have been focused on its evolutionary scenario. In this study, analysis of five chloroplast loci and 47 nuclear microsatellites (nSSR) loci from 38 kumquat and 10 citrus accessions revealed the independent phylogeny of Fortunella among citrus taxa, and that Fortunella mainly comprises two populations: CUL, cultivated Fortunella spp. (F. margarita, F. crassifolia and F. japonica); and HK, wild Hong Kong kumquat (Fortunella hindsii). Genomic analysis based on whole-genome SNPs indicated that the allele frequency of both pupations deviated from the neutral selection model, suggesting directional selection was a force driving their evolutions. CUL exhibited lower genomic diversity and higher linkage strength than HK, suggesting artificial selection involved in its origin. A high level of genetic differentiation (Fst = 0.364) was detected and obviously asynchronous demographic changes were observed between CUL and HK. Based on these results, a new hypothesis for the speciation of Fortunella is proposed.

Hierarchical design and gradient design have been shown to improve the crashworthiness of structures. However, fewer studies combine the two. Therefore, this study combines the two to design a novel double-gradient hierarchical hexagonal tube (DGHHT) based on a hexagonal tube (HT). According to the different axial gradients, they are divided into DGHHT-1 and DGHHT-2. The crashworthiness under multiple loads was studied by finite element simulation. Firstly, the reliability of the finite element model is validated by experimental results. Secondly, compared with single-gradient hierarchical hexagonal tubes (SGHHT), DGHHT have better resistance to global bending under multiple loads. When studying mass effects, it was found that both HT and DGHHT had increased peak force and SEA. When HT is designed as DGHHT-2, specific energy absorption (SEA) can be increased by up to 82.74%. Studying the effects of impact angle found that DGHHT-2 has better resistance to global bending than HT as the angle increases. Studying the effect of DGHHT-2 axial gradient distribution found that reasonable distribution of its axial gradient can further improve its ability to resist global bending. Finally, compared with the structures proposed in other studies, DGHHT-2 also has better resistance to global bending at an impact angle of 30°. The double-gradient hierarchical design in this study can provide new design ideas for crashworthiness design. [ABSTRACT FROM AUTHOR]

AbstractDrawing inspiration from nature’s hierarchical organization, we propose a novel bio-inspired hierarchical multi-cellular circular tubes (BHMC) with a fractal structure. Using an experimentally validated LS-DYNA finite element model, we investigated the impact resistance of this structure under axial loading. Numerical analysis was conducted to explore the energy absorption performance of BHMC tubes with varying numbers of branches, fractal orders, and tube masses. The numerical findings indicate that specific energy absorption (SEA) increases with higher numbers of fractal orders. Specifically, the SEA of 2nd order BHMC tubes surpasses that of conventional multicellular circular and single-layer tubes by approximately 35.07% and 17.10%, respectively. Optimal performance is achieved with the proposed structure featuring tree branching (N = 6) and 2nd order fractal characteristics, yielding the highest specific absorption energy across different parameters. These results offer valuable insights for designing multicellular bilayer tubes with superior energy absorption efficiency, providing an effective guideline for structural optimization. [ABSTRACT FROM AUTHOR]

This study extensively characterizes the out‐of‐plane stiffness and energy harvesting capabilities of a newly proposed anti‐trichiral hierarchical auxetic honeycomb structure, both mechanically and deformationally. By introducing a design concept based on the anti‐trichiral honeycomb (ATCH), a structure with superior out‐of‐plane load‐carrying capacity and excellent auxeticity is achieved. To validate the finite element model, compression simulations are conducted. Comparative investigations into the morphing characteristics and energy harvesting performance between the novel structure and the ATCH are performed. Additionally, the influence of various parameters on the comprehensive performance of the novel auxetic structure is explored. It has been found that the angle φ is most sensitive to the auxetic properties, while the ratio k significantly impacts energy absorption. This research advances the design of novel auxetic structures for potential applications in protective engineering. [ABSTRACT FROM AUTHOR]

AbstractTo enhance the performance of the six-missing rib honeycomb (ASRH), two axisymmetric missing rib honeycombs, ASRH-1 and ASRH-2, are proposed in this study. First, the in-plane impact performance of ASRH, ASRH-1, and ASRH-2 is experimentally compared to verify the accuracy of the finite element model. Then, the deformation patterns, specific energy absorption (SEA), and negative Poisson’s ratio (NPR) effects of the three honeycombs under different parameters were parametrically investigated. The results indicate that ASRH-1 and ASRH-2 exhibit higher SEA than ASRH at an impact velocity of 10 m/s, but the NPR effect does not change significantly. The axisymmetric honeycomb demonstrates no advantage at 50 and 100 m/s high-speed impacts. The Poisson’s ratio effect of the three honeycombs varied greatly with the internal ligament r of the honeycomb. The axisymmetric design offers a new concept for a NPR honeycomb design. [ABSTRACT FROM AUTHOR]

AbstractA new type of bi-double square gradient hierarchical tube (DSGHT) is proposed, and its crashworthiness under consistent wall thickness is analyzed. The results show that the energy absorption (EA), specific energy absorption (SEA), and crush force efficiency (CFE) of DSGHT3 are increased by 1305.14%, 430.14%, and 469.50%, respectively, compared to DSGHT0. The combination of double square tubes and gradient laminar design effectively enhances the crashworthiness of the structure. A parametric study indicates that increasing wall thickness significantly improves crashworthiness, with EA, SEA, and CFE improvements of 805.75%, 125.83%, and 126.83%, respectively, at a wall thickness of 0.8 mm compared to 0.2 mm. However, the effect of wall thickness gradient distribution on structural crashworthiness is minimal. Conversely, the ratio of the inner to outer square tube edge length (δ) significantly impacts crashworthiness; SEA and CFE increase by 37.77% and 37.35%, respectively, when δ is 6/12 compared to 8/12. Finally, DSGHT3 was compared to other hierarchical, tree-shaped fractal structures, and it demonstrated superior crashworthiness. Specifically, DSGHT3 has 35.32% and 34.29% higher SEA and CFE, respectively, compared with MSTL2-2. [ABSTRACT FROM AUTHOR]

AbstractThis study aims to investigate the crashworthiness performance of a novel hierarchical multi-cell double circular tubes (HMDC) structure under axial impact. Various dual-tube structures of different cross-sections were designed. The effects of hierarchical order, peak number of the core column, and inner circle diameter on the structure were analyzed using Abaqus finite element analysis. The results indicate that in dual-tube structures, replacing the traditional multi-cell structure with a hierarchical multi-cell structure in the interlayer significantly improves energy absorption (EA) characteristics. With the inner circle diameter of the HMDC fixed at 20 mm, the ratio of mean crushing force (MCF) to peak crushing force at the third order increased by 70.70% and 35.68% compared to the first and second orders, respectively. Experimental results and finite element results show that the initial peak value differed by 1.47%, indicating a close match between the experimental and simulation results. The parametric study shows that the inner circle diameter and the peak number of the core column significantly affect EA. The findings of this study provide effective guidance for designing multi-cell dual circular tubes with high EA efficiency. [ABSTRACT FROM AUTHOR]