Small Diameter Research Articles

Shrinkable Hydrogels through Host–Guest Interactions: A Robust Approach to Obtain Tubular Cell‐Laden Scaffolds with Small Diameters

AbstractThe availability of realistic in vitro models is crucial for tissue engineering, disease modeling, and drug screening assays. However, reproducing the complex shapes and intricate structures of naturally occurring tissues or organs in the presence of functional cells remains a challenge. For example, it is still not trivial to obtain cell‐laden tubular structures on a micrometer scale present in the nephrons of the human kidney. Here, a unique hydrogel‐based shrinking approach making use of host–guest interactions to decrease the diameters of the preformed hydrogel tubules seeded with cells is proposed as a tool to overcome the abovementioned challenge. The hydrogels are composed of covalently crosslinked methacrylated hyaluronic acid and methacrylated dextran modified with either cyclodextrin or adamantane groups that can form dynamic bonds. The hydrogels are initially formed in the presence of small‐molecule competitors that block any interpolymer host–guest interactions, and the shrinking process is triggered by the release of these competitor molecules. The high shrinking efficiency with a shrinking factor up to eight times in volume and robust cytocompatibility make the host‐guest‐based shrinking approach an appealing tool to obtain hydrogel tubular in vitro models with the desired dimensions on demand.

Balloon angioplasty for cerebral vasospasm in preschool children.

Subarachnoid hemorrhage evolving with cerebral vasospasm and delayed cerebral ischemia may increase morbidity and mortality. Treating vasospasm with balloon percutaneous angioplasty (PTA) in adults is well known, but data in preschool children are scarce. In addition, the smaller diameters and fragility of the vessels in childhood might lead to serious complications. This study presents two cases of cerebral vasospasm in preschool children treated with balloon PTA. Therefore, it may contribute to a better understanding of the role of that technique as an effective treatment modality in this population. Balloon PTA was performed in two children (3 and 4 year-old) with aneurysmal subarachnoid hemorrhage and delayed cerebral ischemia. The procedures were uneventful, and both patients survived without complications or new infarction. Balloon PTA for proximal vasospasm may improve clinical outcomes in selected pediatric patients. Further studies are needed to clarify the best candidates, materials, and techniques.

Scale Production of a Stretchable Fiber Triboelectric Nanogenerator in Customizable Textile for Human Motion Recognition.

Although the fiber-based triboelectric nanogenerator (F-TENG) has been recognized as one of the most promising flexible sensor systems, it is facing a challenge of balancing the performance and the processing scalability. Herein, we develop a hierarchical coaxial F-TENG possessing PU layer, Ag layer, and PA layer from the core to the outer part by an efficient and straightforward two-step braiding method. Owning a small diameter of 1 mm, the F-TENG presents a high linear sensing response, a wide working range of 5 to 150 kPa, and a quick reaction speed of around 200 ms. In addition, it shows high flexibility, cyclic washability, and superior mechanical stability. Furthermore, customizable textiles (e.g., wrist support and socks) that conform perfectly to the human body have been knitted from the F-TENGs as warps or wefts, which are able to monitor human motion signals. Together with an optimized machine learning algorithm, five human motions (stand, slow walk, normal walk, run, and jump) can be analyzed with a precision of up to 99%. In short, this work presents a scalable approach to develop customizable self-powered sensing textiles, offering an excellent wearable digital platform/system for potential motion capture/monitoring, identification, and smart-sports-related applications.

Temporal airy pulses efficiency in thin glass dicing

Abstract Ultrashort pulse laser sources are useful tools for micro- and nano-processing large band gap dielectric materials. One of the biggest advantages of these pulses is the possibility to reach high intensity peaks that promote absorption even in materials transparent to the laser wavelength. In addition, if the pulse temporal distribution is modified, energy absorption enables the ablation of small diameter holes with large depths. In this work, we present preliminary results that implement three types of pulses as precursors for glass dicing: Bandwidth-limited (30 fs at 785 nm), positively, and negatively dispersed Temporal Airy Pulses (TAP). The material of choice was 170 μm thick soda-lime glass, inscribed at 1 kHz repetition rate in tight (50× objective) and loose (20× objective) focusing conditions for different laser energies and scanning speeds. After laser processing, the glass was diced by mechanical stress, with a home built four-point bending stage. We analyzed the quality of the scribed lines at the surface and in cross-section after breaking, as well as the necessary breaking force for all three types of laser pulses. We report that positive TAP produced a neat, flat-cut edge on the glass samples compared with the other implemented pulses.

HPB SO35 - Outcomes of Transcystic Laparoscopic Common Bile Duct Exploration at the time of Laparoscopic Cholecystectomy in patients with small common bile duct diameter

Abstract Background Laparoscopic Cholecystectomy with Laparoscopic Common Bile Duct Exploration (LC+LCBDE) is a single stage therapeutic option for management of choledocholithiasis. There have been limited publications regarding the feasibility of transcystic LCBDE in patients with small (≤8mm) common bile ducts (CBD). This study seeks to examine the outcomes for patients with small ducts who underwent LC+LCBDE via a transcystic approach (LCBDE-t) in a district general hospital over a thirty-month period. Method Prospectively collected data regarding all patients who underwent LC+LCBDE-t over a period from January 2022 to June 2024 was retrospectively reviewed. Data including indication for surgery, CBD diameter, length of stay, complication rate, and readmission rate were determined from Electronic Care Records. Data were analysed using Microsoft Excel. Results 76 patients were identified. CBD diameter (almost all as measured at pre-operative Magnetic Resonance Cholangiopancreatography [MRCP]) ranged from 3.5mm to 8mm (average 6.32). One patient required conversion to open surgery due to difficulties with the LC element of the operation. Median postoperative length of stay was 1 day (range 0-32 days) and readmission rate was 5.33%. Five patients experienced a complication beyond Clavien-Dindo Grade II, with the most serious two being a bile leak and a postoperative bleed, both of which required further surgery. One patient required subsequent Endoscopic Retrograde Cholangiopancreatography (ERCP) for retained CBD stones. Conclusion LCBDE is a safe and effective management option for patients in the setting of choledocholithiasis with small CBD diameter. Small CBD should not necessarily be a deterrent to consideration of transcystic LCBDE as a therapeutic option in appropriately selected patients.

Finite Element Modelling of Circular Concrete-Filled Steel Tubular Columns Under Quasi-Static Axial Compression Loading

This paper presents a modified finite element analysis (FEA) model for predicting the axial compression strength of large-diameter concrete-filled steel tubular (CFST) stub columns, addressing the gap in research that has often focused on smaller diameters. The size effect, which significantly impacts the structural performance of large-diameter CFST columns, is a key focus of this study. The goal is to validate the accuracy and reliability of the modified FEA model by comparing its predictions with experimental data from the literature, specifically examining ultimate axial load capacity, failure modes, and deformed shapes. In addition to validating the model, this study includes a comprehensive parametric analysis that explores how critical geometric parameters such as the diameter-to-thickness (D/t) ratio and length-to-diameter (L/D) ratio affect the axial compressive behavior of CFST stub columns. By systematically varying these parameters, the research provides valuable insights into the load-bearing capacity, deformation characteristics, and failure mechanisms of CFST columns. Furthermore, the material properties of the steel tube—particularly its yield strength—and the compressive strength of the concrete core are investigated to optimize the design and safety performance of these columns. The results indicate that the FEA model shows excellent agreement with experimental results, accurately predicting the axial load-strain response. It was observed that as the diameter of the steel tube increases, the peak stress, peak strain, strength index, and ductility index tend to decrease, underscoring the size effect. Conversely, an increase in the yield strength and thickness of the steel tube enhances the ultimate strength of the CFST columns. These findings demonstrate the reliability of the modified FEA model in predicting the behavior of large-diameter CFST columns, offering a useful tool for optimizing designs and improving safety margins in structural applications.

Effect of Annealing Temperature on the Structural Properties and Performance of ZnO/SnO<sub>2</sub> Nanostructure of AZO-Based Humidity Sensor

Advanced research in metal oxide-based nanotechnology has led to its broad applications, which include humidity sensors as well as electronic devices. Meanwhile, zinc oxide (ZnO)/tin oxide (SnO2) composite nanostructure has established a presence in many electronic devices, and their performance can be further enhanced by electrospraying at high annealing temperatures. This paper explores how annealing temperature influences the structural properties and performance of ZnO/SnO2 nanostructures in AZO-based humidity sensors. The ZnO/SnO2 nanostructures were fabricated on AZO glass utilising electrospraying and then subjected to annealing at various temperatures: 100°C, 200°C, 300°C, 400°C as well as 500°C. The structural characteristics of the synthesized films were analysed utilising Field-Emission Scanning Electron Microscopy (FESEM) as well as X-ray Diffraction (XRD). Additionally, the humidity sensing performance of the films was evaluated based on their response time, sensitivity as well as recovery time. Following the results, a higher annealing temperature resulted in smaller crystallites and smaller diameters within the 71.6–91.9 nm range. Besides, the XRD patterns demonstrate a shift in the (002) peaks towards a higher angle value with incremental annealing temperature. In terms of the humidity sensing performance, the sensitivity level increased with increasing annealing temperature, while the recovery period and response time were reduced. In summary, the annealing temperature significantly influenced the performance of the ZnO/SnO2 composite nanostructures, which recorded the best sensitivity of 173.10, 234 seconds response time, and 80 seconds recovery time after annealing at 500°C.

Abstract 4146316: Venous Remodeling and Occlusion Accompany Arterial Pathology in Patients with Chronic Limb Threatening Ischemia

Background: Chronic limb threatening ischemia (CLTI) is defined as the presence of peripheral artery disease (PAD) in combination with rest pain or tissue loss and represents advanced arterial occlusive disease. Little is known about associated venous pathology as prior pathologic reports were limited to evaluation of maximally diseased arterial lesions. Objectives: To characterize arterial and venous histopathology in patients with CLTI. Methods: Tissue containing peripheral arteries and veins from the femoropopliteal to distal tibial arteries was harvested from 10 patients who underwent amputation for CLTI (Fig 1). Vessels were sectioned at 0.5 cm intervals, and histopathologic features were catalogued across 535 arterial and 493 venous sections. Results: Consistent with PAD, atherosclerotic lesions were more prevalent in proximal than distal arteries; 81.8% (27/33) femoropopliteal sections compared to 26.6% (134/502) of tibial sections. Severe stenosis (>90%) was noted in 21.9% (117) of sections and was associated with atherosclerosis (pathological intimal thickening, fibroatheroma, fibrocalcific or fibro-osseous lesions) in 10.3% (12), luminal thrombi in 68.4% (80), or both in 21.4% (25) of arterial sections. In all patients and in 99.0% (488/493) of venous sections, irrespective of the degree of arterial luminal stenosis, adjacent large (≥1000µm) and small diameter veins revealed marked thickening of the vessel wall comprised of fibrosis and smooth muscle hyperplasia (Fig 2). While large veins retained luminal patency, small veins exhibited severe luminal stenosis or obliteration. Venous thrombosis was uncommon, occurring in 3.0% (15/493) of sections. Conclusions: Venous remodeling with stenosis and occlusion is highly prevalent and coincides with arterial disease pathology in patients with CLTI. This novel finding of previously underappreciated and severely altered venous pathology suggests a possible additional mechanism for limb ischemia in CLTI.

Evaluation of the Highly Ordered Structure, Ligature, and Enzymatic Degradation of Poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate] Elastic Porous Fibers.

We prepared biocompatible elastic fibers with high porosity and high tensile strength from poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate], which is a microbial polyester that can be produced from renewable carbon resources by isothermal crystallization. It was possible to control the pore size by adjusting the isothermal crystallization time. Most of the pores were approximately less than 10 μm in diameter, did not penetrate, and were distributed discontinuously throughout the fibers. The elasticity of the fibers was apparently attributable to the generation of tie molecules with planar zigzag conformations between lamellar crystals and to the deformation of the pores. The ligature area occupied by the porous fibers in surgical knots was reduced by 75% compared with that of nonporous fibers. This is expected to make the ligature more difficult to untie and reduce the feeling of foreign matter. X-ray tomography revealed that the porous fibers had a relatively small fiber diameter owing to the collapse of the porous area. The rate of enzymatic degradation of the porous fibers was more than four times that of nonporous fibers. These results suggest that this elastic porous fiber will have many applications, including in the medical and marine material fields.

Randomly Twisted Hypercubes: Between Structure and Randomness

ABSTRACTTwisted hypercubes are generalizations of the Boolean hypercube, obtained by iteratively connecting two instances of a graph by a uniformly random perfect matching. Dudek et al. showed that when the two instances are independent, these graphs have optimal diameter. We study twisted hypercubes in the setting where the instances can have general dependence, and also in the particular case where they are identical. We show that the resultant graph shares properties with random regular graphs, including small diameter, large vertex expansion, a semicircle law for its eigenvalues and no non‐trivial automorphisms. However, in contrast to random regular graphs, twisted hypercubes allow for short routing schemes.

Measurable morphological features of single circulating tumor cells in selected solid tumors-A pilot study.

Liquid biopsies developed into a range of sensitive technologies aiming to analyze for example, circulating tumor cells (CTCs) in peripheral blood, which significantly deepens understanding of the metastatic process. Nevertheless, examination of CTCs is mostly limited to their enumeration and usually only 2-3 markers-based phenotyping, not offering yet sufficient insight into their biology. In contrast, quantitative analysis of their morphological details might extend our knowledge about dissemination and even improve CTC isolation or label-free identification methods dependent on their physical features such as size, and deformability. Current study was conducted to describe CTCs' and their size, shape, presence of protrusions, and micronuclei across various types of cancers (lung, n = 29; ovarian, n = 24, breast, n = 54; and prostate, n = 33). Epithelial (pan-keratins), mesenchymal (vimentin), and two exclusion markers were used to identify CTCs and classify them into four epithelial and epithelial-mesenchymal transition-related phenotypes using standardized and throughput method, imaging flow cytometry. The morphological characteristics of CTCs, including their nuclei, such as circularity, the maximum, and minimum diagonal values were determined using an open-source software QuPath. On average, detected CTCs (n = 1156) were larger, and more irregular in shape compared to leukocytes/endothelial cells (n = 400). Epithelial and mesenchymal CTCs had the largest (median = 18.2 μm) and the smallest diameter (median = 10.4 μm), respectively. In terms of cancer-specific variations, the largest CTCs were identified in lung cancer, whereas the smallest-in prostate and breast cancers. Epithelial CTCs and those negative for both epithelial and mesenchymal markers exhibited the highest degree of elongation, whereas mesenchymal CTCs were the most irregular in shape. Protrusions and micronuclei were observed extremely rarely within CTCs of breast and prostate cancer (0.6%-0.8% of CTCs). Micronuclei were observed only in epithelial and epithelial-mesenchymal CTCs. This study underscores the significant variability in the morphological features of CTCs in relation to their phenotypic classification or even the particular organ of origin, potentially influencing for example, size-dependent CTC isolation methods. It demonstrates for the first time the morphological measurements of CTCs undergoing epithelial-mesenchymal transition, and some specific morphological details (i.e., protrusions, micronuclei) within CTCs in general.

Insights into Martian bedform migration: Results from Gale, Jezero and Pasteur craters

AbstractAn attempt is made in this study to advance the understanding of the sand movement on Mars by studying the bedform migration at Gale, Jezero and Pasteur craters. The study on the grain size distribution at Gale Crater using Curiosity rover (MAHLI and APXS) observations reveals that the grains with smaller diameters (~50–150 μ) are more prone to migration and vice‐versa, which gives an idea of the necessary requirements that initiate bedform migration. The chemical analysis of the surface materials at the Gale crater revealed elevated concentrations of P2O5, SO3, Cl and Zn in soil compared to sand and active transportation processes for sand but not soil. The comprehensive chemical makeup of the Martian soil (inactive bedforms) and sand (active bedforms) is characterized by its basaltic nature, with enriched volatile elements such as sulphur, chlorine and zinc, and the presence of minerals like plagioclase, pyroxene and olivine due to the cohesive nature of inactive bedforms. Physical weathering and wind flow velocity play a pivotal role in the formation of different sedimentary bodies, impacting grain size distribution and mineralogy. The effect of dust‐lifting on surface features is studied by analysing Perseverance‐MEDA observations at the Jezero crater to understand the short‐term changes in the bedform. These events are found to involve the redistribution of only a small amount of materials and, thereby, changing surface features on Mars over a short period. To detect the bedform migration in the Pasteur crater, several HiRISE images acquired over different time intervals were used. The changes in the ripple crest (~0.29–1.18 m/Earth year) and dune slip face suggest new grain flow events. In the Pasteur crater, extensive changes in sand deposits near the dunes signify a widespread bedform migration. The stronger north‐westerly and north‐easterly winds dominate these changes. Thus, the bedform migration in the three tropical craters exhibits significant variability driven by localized aeolian processes. This variability is crucial for understanding Mars' geological history, current surface dynamics and eventually, helps in planning future missions.

Localized Laser Heat Treatment on AISI 1045 Steel Using a LPBF Laser

ABSTRACTLaser heat treatment (LHT) can provide local microstructure modification for metallic materials. This study investigates the viability of LHT on AISI 1045 steel using a laser designed for laser powder bed processing (LPBF) with a very small beam diameter compared to existing literature. Energy density models from the literature are analyzed and adapted to improve consistency across varying laser properties, mainly focusing on spot size and laser–material interaction time. Fifteen different laser parameter schematics are evaluated, comparing hardness versus depth relations as well as laser‐affected zone (LAZ) profiles. Through adapting the energy density model, new laser parameters are calculated and demonstrated to produce a valid localized heat treatment.

Effects of structural parameters of active pre-chamber on the combustion process of methanol/gasoline TJI rotary engine

The application of Turbulent Jet Ignition (TJI) combustion mode in spark ignition engine can improve combustion efficiency and output power. This paper innovatively proposes the application of active pre-chamber (APC) in rotary engine (RE) to realize this mode. And blending a certain percentage of methanol in gasoline to achieve carbon reduction. A three-dimensional computational model of the APC-RE was developed, and the effects of three APC structural parameters including throat section diameter, throat section length and orifice diameter on the component flow and combustion characteristics were investigated. The results showed that the APC-RE exhibited higher sensitivity to the diameter of the throat section than the length variation under the fixed active fuel injection strategy. The low length or small diameter of the throat section causes insufficient energy in the APC jet, and too high values cause unstable combustion. The optimal APC volume is achieved at a throat length of 8 mm and a diameter of 6 mm, with the highest Indicated mean effective pressure (IMEP) and Indicated thermal efficiency (ITE). Next, The APC volume was fixed and the effect of jet orifice size on RE performance was discussed and the optimal size was determined 1.25 mm, which can further optimize the jet velocity and can continue to increase IMEP and ITE by 1.24 % and 1.46 % respectively.

Natural fibers as promising core materials of vacuum insulation panels

To reduce energy consumption in buildings, this paper investigates the feasibility of using natural fibers as cost-effective, environmentally sustainable core materials for vacuum insulation panels (VIPs). First, a comprehensive experimental study was conducted for 10 potential natural fiber candidates. The thermal conductivities of the 10 natural fiber mats at various vacuum pressures were measured; their compression and morphology properties were quantified. In addition, an analytical model was used to explore the major factors that influence the thermal conductivity of natural fibers as a function of internal air pressure. Results show that recycled cotton, kapok, and bamboo fibers are ideal candidates for VIP core materials; at <0.05 Pa, their thermal conductivities varied between 2 and 4 mW/(m⋅K). Furthermore, for some fibers, thermal conductivity was inversely proportional to fiber density. For the selection of fiber materials for VIP cores, the ideal fiber candidate has a small fiber diameter and a low fiber mat density. Based on thermal measurements, even though the internal air pressure of 5 Pa was enough to attain the minimum thermal conductivity, obtaining internal air pressure below 5 Pa is recommended for prolonged service life, considering small leaks of VIP package barrier films and potential off-gassing from fibers. The simulation results predicting the effective thermal conductivities matched the experimental results well. These findings indicate that natural fiber–based VIPs have the potential to be a sustainable, inexpensive alternative to the current technologies in building insulation materials.

Efficacy of intracameral mydriatics in pediatric lens surgery.

Introduction To evaluate the efficacy of intracameral administration of Mydrane® in children undergoing lens surgery. Methods We set up a single center prospective cohort trial including 40 consecutive patients between 8 weeks and 17 years old who were planned for lens surgery, including cataract, persistent fetal vasculature (PFV) or lens subluxation. We injected 0,1 ml of intracameral Mydrane at the beginning of surgery, no preoperative mydriatic eye drops were used. The aim of the study was to measure pupil size, and to monitor the evolution of the pupil size during surgery and the need for additional pupil expanding techniques. Results In 30 patients (75% (95%CI: 59 - 87%)), we did not need additional manipulations to obtain sufficient pupillary dilatation to perform the surgery and to implant an intraocular lens (IOL) following the bag-in-the-lens (BIL) technique. In the remaining 10 patients (25%), we saw an initiation of dilatation, but not to the required pupil diameter to continue the surgery without additional surgical maneuvers. The duration of surgery was significantly longer in the partial response group, reflecting the need for additional surgical steps. A significant relation between increase of pupillary diameter and age (P = 0.003), gender (P = 0.032) and horizontal corneal diameter (P < 0.001) could be shown. Even at baseline there is a larger pupil diameter in eyes with larger horizontal corneal diameters (p=0.039). No adverse events were observed during this study. Conclusion Intracameral administration of Mydrane resulted in some degree of dilatation in all eyes in this series, 75% of eyes did not need additional techniques to proceed with the surgery. Smaller pupils at baseline, younger age, male sex and small horizontal corneal diameter were related to a poorer response to Mydrane. The mydriasis persisted for the entire duration of the surgery, no ocular adverse events were observed during this study. This leads us to conclude that intracameral Mydrane is an effective and safe way to dilate the pupil in pediatric lens surgery.

In situ iron coating of amorphous boron and characterization of its energy release behavior

Boron was widely employed as metal fuel in solid propellants for its higher gravimetric and volumetric combustion enthalpies. However, the low melting point and high boiling point of B2O3 on the surface of boron particles significantly hinder its ignition and combustion performance, seriously preventing the full realization of its thermodynamic potential. To address this issue, B@Fe composite fuels with different iron contents from 1.59 % to 7.09 % were prepared via liquid phase reduction in this paper and the quasi-static high temperature oxidation, ignition and combustion reaction characteristics and corresponding mechanism were studied, in order to provide effective modification techniques in supporting the large-scale engineering application of boron as metal fuel. The study results show that B@Fe can effectively reduce the ignition temperature and maximum heat flow temperature of amorphous boron, and increase the maximum mass gain rate. The ignition temperature and maximum heat flow temperature have an exponential function with the iron coating content. Iron coated amorphous boron can effectively shorten the laser ignition delay time by more than 50 %, and significantly change the flame structure, flame evolution process and combustion duration. Both amorphous boron and iron-coated amorphous boron flame showed a multi-layer structure, including the outer green flame, the middle yellow flame and the central incandescent flame. However, with the increase of the iron coating content, the flame height increased from 5.5 cm to 6.3 cm, the flame structure changed from mushroom type to triangle type, and the central incandescent flame area increased significantly. The equivalent combustion duration increased from 975 ms to 1997 ms, and the flame temperature increased from 1288 to 1505 °C. The emission spectra of BO2 and BO lines are captured during combustion. B@Fe with the increase of iron content, a large number of small diameter micropores appear in the condensed combustion products(CCPs) of composite fuels, and a grid-like structure was formed. With the increase of iron coating content, the boron content of condensed combustion products decreases, and the oxygen content increases. The main components of CCP include B, B2O3, B6O, FeB, Fe2B and Fe3B. Based on the ignition combustion experiment of B@Fe composite fuel, ignition combustion analysis model of B@Fe composite fuel was established.

Effect of explosives charges types on the jet characteristics, penetration performance and fragmentation patterns of shaped charges

Different explosive materials have been studied numerically and experimentally to assess the efficiency of a small diameter shaped charge in terms of produced jet characteristics and penetration depth into RHA steel targets. 26 different explosives have been simulated numerically using Autodyn hydrocode, whereas recommended explosives have been loaded into small diameter shaped charges by pressing technique and tested by static firing against RHA targets in order to validate the numerical calculations. The numerical analysis has presented an intensive global view about the variation of the shaped charge jets as a potential of the loaded explosive charge efficiencies. A successful trial has been performed to measure the shaped charge jet velocity using detonation velocity VOD 812 apparatus, where its measured value was only 3.6% different from the numerical one for HMX-V5 explosive. Besides, TITAN (L3) flash X-ray radiograph has also been implemented to explore the jet profile using the same explosive type and to measure its jet tip velocity, which has only 2.1% different from that estimated numerically. Extensive fragmentation analysis has been presented, which showed increase in both the fragment number and the fragment speed when the used explosive charge is of high detonation velocity. CL-20 explosive exhibited the largest jet tip velocity and its scaled collapse velocity was found to be 140% of TNT explosive. The calculated average fragment speed has been validated and the measured fragment speed has only 2.3% difference when compared to the SPH calculations.

Comparison of the effects of pre-dilatation with conventional versus larger balloon sizes on clinical outcomes in transcatheter aortic valve implantation with self-expandable valves

Abstract Background Transcatheter aortic valve implantation (TAVI) is considered an established treatment option for patients with severe aortic stenosis. When implanting self-expandable valve, pre-dilatation is often necessary to facilitate optimal transcatheter heart valve (THV) deployment. Traditionally, balloon sizes chosen for pre-dilatation are smaller than the minimum annulus diameter. Insufficient pre-dilatation can result in under-expansion of the THV, necessitating post-dilatation, and can increase the risk of complications. However, this conventional approach may not always yield the best outcomes, prompting a reassessment of balloon sizing strategies to improve procedural success and patient outcomes. Purpose The aim of this study was to investigate the impact on procedural outcomes of using larger balloons, sized less than the mean annulus diameter, for pre-dilatation compared to the traditional practice of using balloons sized less than the minimum annulus diameter during the implantation of self-expandable valves. Methods We analyzed 785 patients who underwent TAVI with self-expandable valve with pre-dilatation out of a consecutive 3880 cases at 6 centers from 2010 to 2023 (Figure 1). Among them, we divided the patients into two groups: those who underwent pre-dilation with balloons smaller than the minimum annulus diameter defined as the Conventional-size group and those who underwent pre-dilatation with balloons smaller than the mean annulus diameter defined as the Large-size group. The primary endpoint of this study was procedural success, stroke and need for permanent pacemaker implantation as designated by the VARC-3criteria. Results Of patients (69% female; mean age 84.9), there were 563 (71.7%) patients in the Conventional-size group and 222 (28.2%) patients in the Large-size group. There was no annulus rupture in either group. The incidence of post-dilatation was significantly higher in the Conventional-size group than in the Large-size group (109 of 563 [19.4%] vs. 23 of 222 [10.3%], p=0.001) (Figure 2). There was no significant difference in the incidence of primary endpoints (all p &amp;gt; 0.05). In post-echocardiographic outcomes, there was no significant difference in effective orifice area, mean pressure gradient, patients-prosthesis mismatch, or paravalvular leakage between the groups (P &amp;gt; 0.05). Conclusions This study demonstrates that a large-size strategy using a balloon smaller than the mean annulus diameter in the deployment of self-expandable valves is safe and may avoid the need for post-dilatation compared to the traditional strategy using a balloon smaller than the smallest diameter.

Usage patterns and outcomes of drug coated ballons at a tertiary care center - a cohort analysis in 462 patients

Abstract Background The usage of drug coated ballons (DCB) in percutaneous coronary interventions (PCI) is rising. Initially applied in in-stent restenosis (ISR), wider clinical applications especially in de novo lesions (DNL) are discussed. Here we aim to assess the pattern of usage as well as the clinical and angiographic outcomes associated with DCB. Methods For this analysis we included all patients treated with DCB during PCI, at a tertiary care centre between 01/2015 and 12/2021. Cath lab results of all patients were screened to assess the DCB indication. Patients were followed up until 09/2022 to assess clinical as well as angiographic complications. Results A total of 7608 interventions were carried out between 2015 and 2021, in 462 (6.1%) a DCB was used. The median follow-up time were 3.1 years (IQR 1.6 to 4.4 years), the median age of our patient population was 66 (IQR 58-75) and 24.7% (n=114) were female. There were 92 of 462 (19.9%) cases including a DNL preparation, 335 (72.5%) cases treating an ISR, in 6 (1.3%) cases both, DNL and ISR were treated, and in 29 (6.3%) cases DCB were used for other reasons (e.g. pre-/ postdilatation in coronary stenting). The mean DCB inflation diameter was significantly higher in ISR with 3.50mm (IQR 3.0-3.5mm) compared to DNL with 2.50mm (2.00-2.50mm, p-value &amp;lt;0.001 ) While the number of DCBs used is rising over time (179 cases [38.7%] in 2015-2018, 283 cases [61.3%] in 2019-2021), the proportion of de novo lesions showed no significant difference (37/179 [20.7%] in 2015-2018, 61/282 [21.6%] in 2019-2021, p-value 0.806, Figure 1). Patients with DCB for ISR had significantly higher rates of arterial hypertension (ISR: 255 [76.1%], DNL: 57 [62.0%], both: 3 [50.0%], other: 20 [69.0%] p value 0.029), hyperlipidaemia (ISR: 228 [68.1%], DNL: 56 [60.9%], both: 2 [33.3%], other: 14 [48.3%], p value 0.041) and previous myocardial infarction (ISR: 231 [69.0%], DNL: 33 [35.9%], both: 2 [33.3%], other: 8 [27.6%], p-value &amp;lt;0.001). When analysing the outcomes, patients with DNL showed lower rates of acute myocardial infarction (8 [8.2%] vs 51 [15.0%]) as well as target lesion (6 [6.1%] vs 56 [16.5%]) and any revascularization (27 [27.6%] vs 122 [35.9%])%]), yet a higher rate of cardiovascular mortality (19 [5.6] vs 9 [9.2%]) during the follow up period compared to patients treated for ISR (Figure 2). Both groups showed a very low rate of target lesion thrombosis within 30 days after PCI (1 [1.0%] vs 1 [0.3%], p-value 0.745). Conclusions The use of DCB in PCIs is increasing, yet as we were able to emphasize with our data, they are primarily used in ISR as well as lesions with a small vessel diameter with favourable outcomes indicated by low event rates. Research should expand beyond small-vessel disease and ISR to assess safety and outcomes of DCB in DNL, larger vessels and bifurcation interventions with one stent to further assess its potential benefits in a wider field of indications.