Wall Thickness Research Articles

Waste rubber recycling in concrete-filled steel tube members: Mechanical performance, reliability and life cycle assessment

This paper focuses on the axial compression mechanical performance, reliability analysis and environmental impact of rubber concrete-filled circular steel tube (RuCFST) columns. Initially, the research of the axial compression performance reveals that enhancing the wall-thickness or yield strength of steel tubes variably increases the yield, peak, and ultimate loads of RuCFST columns. The degree of enhancement of each characteristic point by growing the wall thickness of the steel tube is 5 %–44 %, 6 %–44 %, and 9 %–44 %, respectively; while the degree of enforcement is 5 %–55 %, 23 %–53 %, and 24 %–61 %, respectively, upon yield strength increase. Reliability analysis indicates that higher concrete grades decrease the probability of axial compression failure in RuCFST columns. Raising the yield strength and wall-thickness of steel tubes leads to a reduction in the reliability index. Both larger and smaller live-to-dead load effect ratios adversely impact the reliability index. In addition, the life cycle assessment method was used to evaluate the environmental impact of RuCFST columns, and the analysis was made after considering the superposition effect of waste rubber incineration and recycling into rubber aggregates.

EMBRYONIC FLOWER 1 regulates male reproduction by repressing the jasmonate pathway downstream transcription factor MYB26.

The evolutionarily conserved Polycomb repressive complexes (PRC) mediate genome-wide transcriptional silencing and regulate a plethora of development, as well as environmental responses in multicellular organisms. The PRC2-catalyzed trimethylation of lysine 27 on histone H3 (H3K27me3) is recognized by reader-effector modules of PRC1 to implement gene repression. Here, we report that the Arabidopsis (Arabidopsis thaliana) H3K27me3 effector EMBRYONIC FLOWER 1 (EMF1) interacts with and constrains the R2R3 DNA binding transcription factor MYB26 by a eudicot-conserved motif in the stamen. MYB26 activates the transcription of two NAC domain genes, NAC SECONDARY WALL THICKENING PROMOTING FACTOR1 (NST1) and NST2, whose encoded proteins mediate anther secondary cell thickening in jasmonate (JA)-regulated stamen maturation. In this process, the transcriptional activity of MYB26 is negatively modulated by the JAZ-PRC repressive complex to precisely regulate the expression of NST1 and NST2. Disruption of EMF1 repression stimulates MYB26, leading to the excessive transcription of the two NAC genes and male sterility. Our results reveal a novel mechanism in polycomb-mediated gene silencing and illustrate that the plant Polycomb complex regulates stamen development by preventing the hypersensitivity of JA responses in male reproduction.

Unified analytical theory of nonlinear optical diffraction by nonlinear gratings

When a pump laser shines upon a periodically poled lithium niobate (LN) thin plate nonlinear grating, second-harmonic generation (SHG) and its nonlinear diffraction occurs, with the nonlinear Raman–Nath diffraction (NRND), nonlinear Bragg diffraction (NBD), and nonlinear Cerenkov radiation (NCR) being several prominent examples. In this work we build and present a unified analytical theory to solve SHG for the NRND, NCR, and NBD processes from LN domains, domain walls, and defects. We find that the critical physical entity that governs the nonlinear diffraction is the effective nonlinear coefficient for each Fourier wave component. The analytical theory has a great generality and applicability scope. It allows us to retrieve and analyze everything about the dependence of SHG nonlinear diffraction on a series of physical and geometrical parameters such as the pump laser intensity, polarization, incidence polar and azimuthal angles, the LN thin plate thickness and its crystalline orientation, LN domain size and pitch, domain wall thickness and crystalline configuration, defect size and crystalline configuration, and the SHG diffraction beam angle and polarization. The analytical theory also enables us to analyze deeply the similarities and differences of the three nonlinear diffraction processes NRND, NCR, and NBD, build a smooth and broad connection bridge among these three processes, and construct a unified physical picture to understand, describe, and exploit these three processes of seemingly big difference. Besides, the analytical theory can be applicable to handle nonlinear diffraction by domains, domain walls, and defects in other more complicated 2D and 3D nonlinear gratings made from LN and other nonlinear crystals. Finally, the analytical theory can help to build a bridge connecting the extrinsic SHG nonlinear diffraction properties with the intrinsic domain poling and inversion material and physical properties of LN and other nonlinear crystals and explore novel nonlinear optical devices and technologies.

Effects of moderate-intensity aerobic training on cardiac structure and function in type 2 mellitus diabetic rats: Based on echocardiography and speckle tracking

PurposeThe present study aimed to evaluate the cardiac function changes using Layer-specific Speckle-tracking echocardiography (LS-STE) induced by Moderate-intensity aerobic training (MIAT) in Type 2 diabetes mellitus (T2DM) rats. MethodsTwenty-six rats were divided into four groups: the Control group (Con), the Training control group (CT), the T2DM group (DM), and the T2DM training group (DT). The CT and DT groups underwent an 8 weeks MIAT. Cardiac structure and function were evaluated by echocardiography and LS-STE. ResultsCompared with the Con group, left atrial diameter (LAD), left ventricular end-diastolic diameter(LVEDD), relation wall thickness (RWT), and left ventricular mass (LVM) were significantly higher, and the endo-, mid-, and epi-longitudinal strain (LS), global radial strain (GRS), and endo- and mid-circumferential strain (CS) were significantly lower in DM rats (all p < 0.05). The endo-, mid-, and epi-LS, GRS, endo- and mid-CS were increased in DT rats compared with DM rats (all p < 0.05). Compared with Con rats, CT rats had a significant increase in LVEDD and LVM (all p < 0.05), meanwhile myocardial strains had no significant differences (all p > 0.05). ConclusionLS-STE was a sensitive method to assess subclinical myocardial changes in T2DM rats. MIAT had the benefit of reversing cardiac systolic subclinical dysfunction in T2DM rats.

Tension performance of joint made in cold-formed square tube with self-tapping screw connections

The tension behavior of cold-formed square tube (CFST) screw connections was investigated experimentally and numerically. Ten test specimens were fabricated from the square tubes connected by external steel plates and internal tube applying self-tapping screws such that the number of screws was varied. In addition, the mechanical properties of the single-screw connections were obtained through single shear tests. Experimental results revealed that an increase in the number of screws led to higher bearing capacity and stiffness in the specimens. Shear failure of the screws was observed as the primary failure mode. When the number of the screws was equal in both types of the specimens, those with the internal tube exhibited superior tensile behavior than the ones with external steel plates. Subsequently, finite element (FE) models of the test specimens were developed. Upon validation of the test results, an extensive parametric study was conducted to further examine the influence of the design parameters on the tensile behavior of the CFST screw connections. Variation of the arrangement of screws, wall thickness of steel plates and their strength had only a minor influence on the tension behavior, and steel strength had little influence on the tension behavior and the number, spacing, and diameter of the screws were the key parameters affecting the tension behavior of the CFST screw connections. Based on the test results and FE analyses, the existing calculation method was modified, and a formula for calculating the tensile bearing capacity of the CFST screw connections was obtained. Comparison with the results indicate that the formula was conservative and reliable for determining the tensile capacity of CFST screw connections.

A Modified Reentrant Metamaterial with Equal and Enhanced Orthogonal Elastic Properties

Herein, an improved mechanical metamaterial is proposed, which is derived from the decomposition, rotation, and reassembly of reentrant structures. The structure is parametric, allowing for rapid redesign. The study focuses on the variations in equivalent stiffness and Poisson's ratio of the structure within the linear elastic range when internal rib angle θ changes. First, based on homogenization simulation analyses, it has been verified that this design achieves the tailorable equivalent elastic modulus and Poisson's ratio over a wide range, meanwhile, maintaining equal elastic properties in the orthogonal direction at all times. Second, to reduce future repetitive experiments, an interpolation model is established to expand the design domain. The fitting formula indicates that by modifying θ and relative wall thickness t/L0, the elastic performance of the structures can be tailored. Additionally, the impact of boundary conditions is discussed to minimize experimental costs. Finally, the accuracy of the simulations is validated through uniaxial compression tests.

Microstructure and mechanical properties of thin-walled TA1 titanium pipes fabricated by high-frequency induction welding

High frequency induction welding (HFIW) was effectively employed for the high-speed fabrication of thin-walled TA1 titanium pipes (TWTPs) with a nominal wall thickness of ∼0.6 mm. The microstructure and mechanical properties of TWTPs manufactured under varying welding parameters were investigated. The weld zone (WZ) exhibits a waist shape measuring ∼622 μm in width, and the width of the heat-affected zone (HAZ) spans between 763 and 864 μm. Both the WZ and HAZ are composed of a mixture of coarse serrated α grains with fine acicular and twins, while the BM retains equiaxed grains. This unique microstructure was resulted from the thermal cycling during HFIW, contributing to a notable increase in microhardness within the WZ compared to both the HAZ and the BM. Optimal manufacturing conditions were identified at a welding power of 14.4 kW, a welding speed of 60 m/min, an opening angle of 6°, and a squeeze displacement of 0.2 mm, yielding the TWIP with a tensile strength of ∼307 MPa and tensile elongation of ∼27%. Tensile fracture analysis revealed that failure predominantly occurred within the BM, underlining a ductile fracture mode characterized by pronounced dimple formations. The enhanced mechanical performance of the weld joints can be attributed to the heterogenous microstructure in the WZ, where the presence of large serrated α-grains enhances ductility, and the fine martensite and twins contribute to the high strength.

Altered placental expression of genes related to Vitamin D Metabolism and their correlation with spiral artery remodeling in Preeclamptic Women

Background: Several studies reveals the correlation of preeclampsia (PE) with low vitamin D (VD) level due to disturbed trophoblast invasion and failure of spiral artery remodeling. The metabolism of VD is regularized by it signaling molecules expressed by the placenta during pregnancy. Therefore, this study was designed to assess and compare the levels of VD and it signaling molecules in placentae from normotensive and preeclamptic pregnancies and their correlation with spiral artery remodeling.Methods: This study was carried out at Department of Anatomy at Liaquat University of Medical &amp; Health Sciences, Jamshoro after ethical approval on placentae of 122 parturients; 61 from normal and 61 from preeclampsia, data was collected on predesigned proforma and was analyzed on SPSS 23.Results: The mean and standard deviation of maternal age, gestational age, and parity was 32.73±5.9 years, 37.3±3.6 weeks and 3±1 respectively. The wall thickness of SA and VD when compared in two groups found statically significant. Vitamin D signaling molecules were determined by immunostaining compared in two groups by applying Mann Whitney U test and Pearson’s correlation which reveals significant differences in preeclamptic versus controls.Conclusions: Despite extensive research indicating a link between low levels of VD and its signaling molecules in the context of inadequate spiral artery remodeling, there is still a need for further investigation to fully understand the mechanisms underlying this association in preeclampsia.Keywords: Preeclampsia; Remodeling; Spiral artery; Vitamin D; Vitamin D signaling molecules

PBP4 is required for serum-induced cell wall thickening and antibiotic tolerance in Staphylococcus aureus.

The bacterial pathogen Staphylococcus aureus responds to the host environment by synthesizing a thick peptidoglycan cell wall, which protects the bacterium from membrane-targeting antimicrobials and the immune response. However, the proteins required for this response were previously unknown. Here, we demonstrate by three independent approaches that the penicillin-binding protein PBP4 is crucial for serum-induced cell wall thickening. First, mutants lacking various non-essential cell wall synthesis enzymes were tested, revealing that a mutant lacking pbp4 was unable to generate a thick cell wall in serum. This resulted in reduced serum-induced tolerance of the pbp4 mutant toward the last resort antibiotic daptomycin relative to wild-type cells. Second, we found that serum-induced cell wall thickening occurred in each of a panel of 134 clinical bacteremia isolates, except for one strain with a naturally occurring mutation that results in an S140R substitution in the active site of PBP4. Finally, inhibition of PBP4 with cefoxitin prevented serum-induced cell wall thickening and the resulting antibiotic tolerance in the USA300 strain and clinical MRSA isolates. Together, this provides a rationale for combining daptomycin with cefoxitin, a PBP4 inhibitor, to potentially improve treatment outcomes for patients with invasive MRSA infections.

Advanced ultrasound diagnosis of extrahepatic bile duct lesions.

Ultrasound (US) has high specificity and sensitivity, and it should be performed first for patients with suspicion of biliary tract cancer. However, the complicated anatomy in addition to the gas images makes it difficult to delineate the entire extrahepatic bile duct (EHBD). The keys to depiction of EHBD are the "J" shape manipulation in the left lateral decubitus position and the use of magnified images with high-frequency transducers. Furthermore, indirect findings such as gallbladder (GB) distension, BD dilatation, and debris echo in the GB and BD are also important for detecting occult lesions, particularly in the ampullary region of Vater. For the differential diagnosis of BD wall thickening, the spreading pattern in the long and short axial directions should be assessed first. Then, the characteristics of the innermost hyperechoic layer (IHL) and outermost hyperechoic layer (OHL) should be evaluated. Asymmetrical wall thickening, absence of IHL, and presence of irregularity or discontinuity in OHL are characteristic patterns of cholangiocarcinoma (CCA). Because CCA is the most common BD polypoid lesion, it is important to diagnose tumor extension and depth invasion in addition to differential diagnosis. Nodular-type CCA is usually hypoechoic and more likely to invade vertically. In contrast, papillary-type CCA is often hyperechoic and extends laterally. Contrast‑enhanced US may be useful for evaluating these findings. However, if the possibility of CCA cannot be ruled out or a definitive diagnosis is needed, a transpapillary biopsy or endoscopic US-guided tissue acquisition should be considered.

First Detection of Pseudocerradoa paullula Causing Aroid Leaf Rust on Swiss Cheese Plant (Monstera deliciosa) in Virginia.

Monstera deliciosa Liebm. (Araceae) is a monocotyledonous plant that is native to tropical forests of southern Mexico to Panama. It is widely grown as an ornamental in the United States because of its easy maintenance and attractive, fenestrate leaves. On May 10th, 2024, at a nursery and garden center in Henrico County, Virginia, four M. deliciosa plants in 3.8 L containers were observed with necrotic spots surrounded by a yellow halo on the leaves (Fig. 1A). Uredinia were present in the center of the lesions with dense, reddish-brown sporulation mostly on the abaxial surface of the leaves (Fig. 1B). Urediniospores with pedicels were golden brown in color, globose, echinulate, with two opposite germ pores, averaging (28) 25.2 x 25 (23) µm (n = 40) in size and a wall thickness of 1.5 to 2 µm (n = 40) (Fig. 1F - K). Telia were not present. The host, symptoms, and urediniospore size was comparable to reports of Pseudocerradoa paullula (Syd. & P. Syd.) M. Ebinghaus & Dianese from South Carolina (22.9 to 27.9 μm), Florida (24 to 31 μm), and Japan (24.8 to 29.3 μm) (Ebinghaus et al. 2022; Sakamoto et al. 2023; Urbina et al. 2023; Yang et al. 2023). Urediniospores from the infected plants were collected with a sterile needle and DNA was extracted using a Qiagen DNeasy PowerLyzer Microbial Kit (Germantown, MD) according to the manufacturer's instructions. PCR and sequencing of the small ribosomal subunit (SSU) and large ribosomal subunit (LSU) gene regions was performed with primer sets NS1/Rust18SR and LRust1R/LR3 (Beenken et al. 2012; Vilgalys and Hester 1990). The resulting 1,630bp and 638 bp sequence fragments of the SSU and LSU loci from strain GS24-AE50 were deposited into the NCBI Genbank database under accessions PQ059898 and PQ059897, respectively. A pairwise alignment of the SSU gene shared 1,363/1,366 (99%) nucleotides with the P. paullula voucher (ON887197) from Florida. A Genbank nBLAST analysis of the LSU gene shared 636/638 (99%), 636/638 (99%), and 592/600 (99%) nucleotides with vouchers from M. deliciosa from South Carolina (OQ746460), Florida (ON887197) and Japan (OK509070) (Sakamoto et al. 20222; Urbina et al. 2023; Yang et al. 2023). Koch's postulates were fulfilled by spraying four, healthy, non-wounded M. deliciosa plants to run-off with a urediniospore suspension (1 x 106 spores/ml distilled water, 20 ml per plant) that was collected from the original infected plants. An additional four, healthy control plants were sprayed with distilled water only. After 6 weeks in a greenhouse at 22 ± 2°C with ≥85% relative humidity under an 8-h photoperiod, uredinia in the center of lesions identical to those on the original symptomatic plants developed on 12 out of 20 leaves from the inoculated plants, while all the leaves from the control plants remained asymptomatic (Fig.1C - E). Urediniospores collected from the inoculated plants were morphologically identical to the urediniospores from the original infected plants with 100% LSU sequence homology to accession PQ059897. Globally, P. paullula has been reported from Australia, China, Japan, Malaysia, the Philippines, and the United States, where the pathogen was detected at the port of Los Angeles in 2014, Florida in 2019, and South Carolina in 2023 (Sakamoto et al. 2023; Shaw et al. 1991; Urbina et al. 2023; Yang et al. 2023). Although the pathogen is not known to be established in Virginia, the recent surge of reports suggests that the pathogen's distribution is expanding. The impact of aroid leaf rust on M. deliciosa production is unclear, but it has the potential to reduce the aesthetic and commercial value of plants under favorable conditions.

Understanding the Etiopathogenesis of Cardiomyopathies: New Insights

Background Cardiomyopathy, a rare heart disease, is characterized by abnormalities in cardiac wall thickness and chamber size, leading to impaired contraction, relaxation, conduction, rhythm, and reduced pumping ability. Aim This review aims to provide a comprehensive understanding of cardiomyopathy by examining its various aspects Method A literature survey was conducted using online databases such as PubMed, Google Scholar, and Web of Science, covering publications from January 1995 to July 2023. Result Genetic mutations in key muscle contraction genes (MYH7, MYL2, MYL3, MYBPC3, TNNT2, TPM1, TNNI3, ACTC) contribute to cardiomyopathy. Additionally, epigenetic markers in genes like FKBP5, TBX5, HAND1, POLA2, PLAAT3, and CCDC88B, along with environmental factors such as alcohol addiction, smoking, and stress, significantly influence disease risk. Genetic testing, including whole exome/genome sequencing, has revolutionized diagnosis, enabling early detection and intervention. Familial genetic testing facilitates personalized management. Conclusion Cardiomyopathy is a complex disease with genetic and environmental influences. Various techniques, including genetic testing, aid in its identification and management. Furthermore, machine learning (ML) techniques have emerged as valuable tools in understanding and predicting cardiomyopathy outcomes.

Study on foaming behavior of block copolymer/inorganic particles co‐construction of toughened epoxy resin foams

AbstractLow toughness and brittleness limit its application range of thermosetting epoxy resin (EP) based foams. In current research, inorganic particles are commonly utilized as heterogeneous nucleating agents to enhance foaming quality and EP toughness. However, the increasing inorganic particle content usually leads to particle agglomeration, which negatively impacts foaming quality and reduces EP performance. Block copolymers, which appear as liquid to effectively mitigate agglomeration, are employed as toughening materials for EP. In this study, a small number of modified calcium silicate particles (MCS) were used as anchor points to induce the distribution of block copolymers (P‐F68) to improve EP toughness and effectively enhance cell nucleation, thus, EP/MCS/P‐F68 foams performance was improved. The research results showed that EP foams obtained excellent cell structure and very small foam density (0.256 g/cm3) at the P‐F68 content of 10 wt%. The continuous increase of P‐F68 content would lead to the thickening of cell wall and the increase of cell size. Simultaneously, the core‐shell structure formed by P‐F68 in EP effectively enhanced the toughness of EP foams and mitigated its brittleness, offering crucial theoretical guidance for toughening and regulating the cell structure of EP foams.

Role of gastric ultrasound in pediatric Menetrier's disease: Report of two cases

AbstractMenetrier's disease (MD) is a protein‐losing gastropathy characterized by acute generalized edema due to hypoalbuminemia. MD is rare in childhood, and it is commonly associated with cytomegalovirus infection. We reported two children, who presented with a history of generalized edema after some days of abdominal pain and diarrhea. Laboratory tests showed hypoalbuminemia with no proteinuria. Thoracic and abdominal ultrasound (US) revealed respectively pleural and pericardial effusion and ascites. A specific gastric echography showed gastric wall thickening (&gt;3 mm) and upper gastrointestinal endoscopy revealed prominent folds in the gastric body and fundus, with a subsequent histological confirmation of Menetrier diagnosis. They were discharged after several albumin infusions. A US follow‐up confirmed the remission of the disease after 1 and 6 months. Gastric US revealed accurate in the diagnosis of this rare condition and in its follow‐up. avoiding a second endoscopy in the short term.

GhGRF4/GhARF2-GhGASA24 module regulates fiber cell wall thickness by modulating cellulose biosynthesis in upland cotton (Gossypium hirsutum).

Fiber elongation rate is an essential characteristic of cotton fiber in the textile industry, yet it has been largely overlooked in genetic studies. Gibberellins (GAs) and auxin (IAA) are recognized for their role in directing numerous developmental processes in plants by influencing cell differentiation and elongation. However, the degree to which GA-IAA interaction governs cellular elongation in cotton fiber cells remains to be fully understood. In this study, we identified a causal gene, Gibberellic Acid-Stimulated in Arabidopsis 24 (GhGASA24), that appears to be responsible for fiber elongation rate via regulating fiber cell wall thickness. Subsequent experiments revealed that GhGASA24 influences cell wall formation by promoting the expression of GhCesA8 and GhCesA10. Our findings suggest that Auxin Response Factor 2 (GhARF2) regulates fiber elongation rate by directly binding to the AuxRE elements in GhGASA24 promoter. In addition, we identified Growth Regulation Factor 4 (GhGRF4) as a transcription factor that interacts with GhARF2 to form a heterodimer complex, which also transcriptionally activates GhGASA24. Intriguingly, GhGRF4 regulates GhARF2 expression by directly binding to its promoter, thereby acting as a cascade regulator to enhance the transcriptional levels of GhGASA24. We propose that the GhGRF4/GhARF2-GhGASA24-GhCesAs module may contribute to fiber cell wall thickness by modulating cellulose biosynthesis, and provide a theoretical basis for improvement of fiber quality.

Multi-modal characterisation of early-stage, subclinical cardiac deterioration in patients with type 2 diabetes.

Type 2 diabetes mellitus (T2DM) is a major risk factor for heart failure with preserved ejection fraction and cardiac arrhythmias. Precursors of these complications, such as diabetic cardiomyopathy, remain incompletely understood and underdiagnosed. Detection of early signs of cardiac deterioration in T2DM patients is critical for prevention. Our goal is to quantify T2DM-driven abnormalities in ECG and cardiac imaging biomarkers leading to cardiovascular disease. We quantified ECG and cardiac magnetic resonance imaging biomarkers in two matched cohorts of 1781 UK Biobank participants, with and without T2DM, and no diagnosed cardiovascular disease at the time of assessment. We performed a pair-matched cross-sectional study to compare cardiac biomarkers in both cohorts, and examined the association between T2DM and these biomarkers. We built multivariate multiple linear regression models sequentially adjusted for socio-demographic, lifestyle, and clinical covariates. Participants with T2DM had a higher resting heart rate (66 vs. 61 beats per minute, p < 0.001), longer QTc interval (424 vs. 420ms, p < 0.001), reduced T wave amplitude (0.33 vs. 0.37mV, p < 0.001), lower stroke volume (72 vs. 78ml, p < 0.001) and thicker left ventricular wall (6.1 vs. 5.9mm, p < 0.001) despite a decreased Sokolow-Lyon index (19.1 vs. 20.2mm, p < 0.001). T2DM was independently associated with higher heart rate (beta = 3.11, 95% CI = [2.11,4.10], p < 0.001), lower stroke volume (beta = -4.11, 95% CI = [-6.03, -2.19], p < 0.001) and higher left ventricular wall thickness (beta = 0.133, 95% CI = [0.081,0.186], p < 0.001). Trends were consistent in subgroups of different sex, age and body mass index. Fewer significant differences were observed in participants of non-white ethnic background. QRS duration and Sokolow-Lyon index showed a positive association with the development of cardiovascular disease in cohorts with and without T2DM, respectively. A higher left ventricular mass and wall thickness were associated with cardiovascular outcomes in both groups. T2DM prior to cardiovascular disease was linked with a higher heart rate, QTc prolongation, T wave amplitude reduction, as well as lower stroke volume and increased left ventricular wall thickness. Increased QRS duration and left ventricular wall thickness and mass were most strongly associated with future cardiovascular disease. Although subclinical, these changes may indicate the presence of autonomic dysfunction and diabetic cardiomyopathy.

Prehospital Trauma Compendium: Traumatic Pneumothorax Care – a position statement and resource document of NAEMSP

ABSTRACT Emergency Medical Services (EMS) clinicians manage patients with traumatic pneumothoraces. These may be simple pneumothoraces that are less clinically impactful, or tension pneumothoraces that disturb perfusion, lead to shock, and impart significant risk for morbidity and mortality. Needle thoracostomy is the most common EMS treatment of tension pneumothorax, but despite the potentially life-saving value of needle thoracostomy, reports indicate frequent misapplication of the procedure as well as low rates of successful decompression. This has led some to question the value of prehospital needle thoracostomy and has prompted consideration of alternative approaches to management (e.g., simple thoracostomy, tube thoracostomy). EMS clinicians must determine when pleural decompression is indicated and optimize the safety and effectiveness of the procedure. Further, there is also ambiguity regarding EMS management of open pneumothoraces. To provide evidence-based guidance on the management of traumatic pneumothoraces in the EMS setting, NAEMSP performed a structured literature review and developed the following recommendations supported by the evidence summarized in the accompanying resource document. NAEMSP recommends: EMS identification of a tension pneumothorax must be guided by a combination of risk factors and physical findings, which may be augmented by diagnostic technologies. EMS clinicians should recognize the differences in the clinical presentation of a tension pneumothorax in spontaneously breathing patients and in patients receiving positive pressure ventilation. EMS clinicians should not perform pleural decompression in patients with simple pneumothoraces but should perform pleural decompression in patients with tension pneumothorax, if within the clinician’s scope of practice. When within scope of practice, EMS clinicians should use needle thoracostomy as the primary strategy for pleural decompression of tension pneumothorax in most cases. EMS clinicians should take a patient-individualized approach to performing needle thoracostomy, influenced by factors known to impact chest wall thickness and risk for iatrogenic injury. Simple thoracostomy and tube thoracostomy may be used by highly trained EMS clinicians in select clinical settings with appropriate medical oversight and quality assurance. EMS systems must investigate and adopt strategies to confirm successful pleural decompression at the time thoracostomy is performed. Pleural decompression should be performed for patients with traumatic out-of-hospital circulatory arrest (TOHCA) if there are clinical signs of tension pneumothorax or suspicion thereof due to significant thoraco-abdominal trauma. Empiric bilateral decompression, however, is not routinely indicated in the absence of such findings. EMS clinicians should not routinely perform pleural decompression of suspected or confirmed simple pneumothorax prior to air-medical transport in most situations. EMS clinicians may consider placement of a vented chest seal in spontaneously breathing patients with open pneumothoraces. In patients receiving positive pressure ventilation who have open pneumothoraces, chest seals may be harmful and are not recommended. EMS physicians play an important role in developing curricula and leading quality management programs to both ensure that EMS clinicians are properly trained in the recognition and management of tension pneumothorax and to ensure that interventions for tension pneumothorax are performed appropriately, safely, and effectively.

Design and study of crashworthiness for square vicsek fractal hierarchical multicellular tubes under axial compression

Through extensive examination of thin-walled structures, the efficacy of enhancing the crashworthiness of thin-walled tubes via layered structures has been confirmed. In this study, we introduce a novel design called the square Vicsek fractal hierarchical multicellular tube (SVFHMT), which integrates principles from fractal science, specifically Vicsek fractals. Unlike conventional layered structures that align along a single direction, our design incorporates layers evenly distributed at five positions throughout the structure, resulting in a more uniform material distribution compared to traditional layering methods. In this paper, the verified finite element model is used to analyze the crashworthiness of the structure, and the effects of levels, wall thickness, wall thickness ratio of different levels and height to diameter ratio on the crashworthiness of the structure are discussed. The mean crushing force (MCF) of SVFHMT is predicted by Simplified Super Folding Element theory. Our findings highlight the significant influence of layering, wall thickness, and ratios of wall thickness between layers on the crashworthiness of the structure. Specifically, for structures of equal mass, the energy absorption of second-order SVFHMTs and third-order SVFHMTs demonstrates substantial improvements compared to square nine-cell tubes, with increases of 51.05% and 91.70%, respectively. Moreover, when maintaining equal mass for second-order SVFHMTs with differing ratios of wall thickness between layers, specific energy absorption ranges from 15.69 kJ/kg to 21.29 kJ/kg. Notably, the maximum error between theoretical and simulated values of the mean crushing force for each order of SVFHMT is only 7.34%. This underscores the effectiveness of our novel layer design strategy, which diverges significantly from conventional approaches and offers valuable insights for advancing layered structures further.

Peripheral Ischemia and Necrosis Revealing Buerger&amp;apos;s Disease in an Internal Medicine Department

Buerger&amp;apos;s disease is a systemic vasculitis strongly correlated with tobacco use. It entails a heavy socio-occupational impact. We report the case of a 26-year-old patient with ischemia of the lower limbs revealing Buerger’s disease. He is known smoker with passive exposure to Indian hemp. He was seen for ischemic foot pain that had been progressing for a year. Involvement began in the left big toe. Subsequently, hyperalgesic necrotic lesions were observed on the 3rd, 4th and 5th toes of the foot. Biological investigations revealed an inflammatory syndrome with normocytic anemia and increased C-reactive protein. Retroviral, syphilitic, Hepatitis B and C viruses and SARS-CoV-2 serologies were negative. Antinuclear antibodies were initially borderline at 100 IU with speckled fluorescence, then negative on control. Neutrophil cytoplasmic antibodies and antiphospholipid antibodies were negative. Investigation of thrombophilia was non-contributory, notably factor V mutation testing, antithrombin III assay, proteins C and S and fibrinogen. An arterial ultrasound revealed extensive arterial thrombosis with thickening of the femoral arterial vessel walls. Thromboangiitis obliterans was confirmed and the patient was put on corticosteroids and adjuvant therapy. Surgical treatment was performed 4 months later. Buerger&amp;apos;s disease is a serious vascular disorder which must be diagnosed very early in order to prevent complications. Early smoking cessation leads to remission in the early phase.

Clinical features, imaging findings, and outcomes of acute abdominal pain in systemic lupus erythematosus: comparing mesenteric vasculitis, non-mesenteric vasculitis, and surgical conditions.

To determine the spectrum, clinical features and outcomes in systemic lupus erythematosus (SLE) patients with acute abdominal pain (AAP). Medical records of SLE patients in a lupus cohort from January 1987 to June 2023 were reviewed. Patients with AAP requiring hospitalization were identified and categorized into 3 groups: lupus mesenteric vasculitis (LMV), non-LMV, and surgical AAP. Each AAP episode represented one patient. Of 1,538 patients in the cohort, 62 (4.03%) had 93 episodes of AAP. After exclusion, 31 patients had 39 LMV episodes, and 30 had 40 non-LMV episodes (19 due to surgical AAP). Seventy-six of the 79 AAP episodes (96.20%) were in females, with a mean ± SD age and median (IQR) disease duration of 36.76 ± 13.60 years and 6 (2, 9) years, respectively. Patients in the LMV group had more fever, nausea and vomiting, and diarrhea than those in the non-LMV group. They also had more small bowel involvement, bowel wall thickening, target water enhancement signs, mesenteric vessels engorgement and mesenteric fat cloudiness, and higher SLE disease activity. These differences were more pronounced when compared to the surgical AAP group. Treatment with corticosteroids and immunosuppressive drugs gave favorable outcomes in the LMV group. Two of 40 (5.00%) non-LMV AAP patients died, of which 1 (5.26%) was in the surgical AAP group. LMV was common among SLE patients admitted for AAP. LMV usually presented with fever, gastrointestinal dysmotility symptoms, diffused abdominal pain, together with evidence of active disease. Localized abdominal pain with peritoneal signs favored surgical AAP. Key Points • Lupus mesenteric vasculitis is common among SLE patients presenting with acute abdominal pain. Its presence often associates with gastrointestinal symptoms together with other clinical manifestations of SLE • The signs in abdominal computed tomography findings are not specific and could be observed in other causes of abdominal pain in SLE. Interpretation of these signs should be cautionary and accompanied by history taking and physical abdominal findings • Treatment of lupus mesenteric vasculitis with corticosteroids alone, or in combination with immunosuppressive drugs, usually results in good outcomes.