We employ molecular dynamics simulations to investigate the shock compression of linear semiflexible polymers. While the propagation velocity of a shock primarily depends on density, both chain rigidity and chain orientation significantly influence the shock width and the final temperature of the system. In general, the shock wave triggers molecular buckling in chains oriented perpendicular to the compression front. Following the passage of the front, the semiflexible chains buckle with a wavelength that decreases with the compression speed as ∼ , and subsequent relaxation leads to a banana-like liquid crystal phase. In ordered systems with molecules oriented perpendicular to the compression front, the shock width increases by a factor of up to 10 compared to a similar isotropic system, resulting in enhanced shock energy absorption. These findings indicate that chain stiffness plays a critical role in the impact absorption properties of polymeric materials.
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http://dx.doi.org/10.1039/d3sm00765k | DOI Listing |
Adv Sci (Weinh)
December 2024
Graduate School of Biomedical Engineering, Faculty of Engineering, and Tyree Institute of Health Engineering (IHealthE), UNSW Sydney, Kensington Campus, Sydney, NSW, 2052, Australia.
Hemodynamic stabilization is crucial in managing acute cardiac events, where compromised blood flow can lead to severe complications and increased mortality. Conditions like decompensated heart failure (HF) and cardiogenic shock require rapid and effective hemodynamic support. Current mechanical assistive devices, such as intra-aortic balloon pumps (IABP) and extracorporeal membrane oxygenation (ECMO), offer temporary stabilization but are limited to short-term use due to risks associated with prolonged blood contact.
View Article and Find Full Text PDFNMC Case Rep J
December 2024
Department of Neurosurgery, Fukushima Medical University, Fukushima, Fukushima, Japan.
Although rare, penetrating cervical vascular injury poses significant challenges with a poor patient prognosis, often attributed to severe hemorrhage and accompanying injuries. We encountered a case of hemorrhagic shock resulting from a penetrating injury to the common carotid artery (CCA), which was successfully managed using a combination of endovascular therapy and direct surgical intervention. A 23-year-old man presented with a self-inflicted stab wound on the left side of his neck from a kitchen knife.
View Article and Find Full Text PDFJ Neurosurg Case Lessons
December 2024
Division of Neurosurgery, Children's Hospital Los Angeles, Los Angeles, California.
Background: Glossopharyngeal neuralgia (GPN) is a rare condition typically manifesting as paroxysms of sharp, lancinating pain localized to the middle ear and auditory canal, base of the tongue, tonsillar fossa, and region just inferior to the angle of the mandible. Vascular compression is a common etiology, and microvascular decompression (MVD) has been established as a safe and efficacious treatment in adults. With the exception of one report of an adult patient undergoing the procedure for symptomatology that began in adolescence, there are no published cases of MVD for GPN in pediatric patients to the author's knowledge.
View Article and Find Full Text PDFJ Vis Exp
December 2024
State Key Laboratory of Trauma, Burns and Combined Injuries, Medical Center of Trauma and War Injury, Daping Hospital, Army Medical University;
In this study, we developed and validated a hybrid quantitative model for simulating upper extremity junctional hemorrhage in swine, aiming to advance the development of pre-hospital hemostatic products. Utilizing 12 healthy 8-month-old male Yorkshire swine, we demonstrated the feasibility of a swine axillary artery injury model for evaluating hemostatic efficacy. Animals were divided into three groups to undergo volume-controlled hemorrhage (VCH), mimicking Class I-III hemorrhagic shock by withdrawing blood at different rates.
View Article and Find Full Text PDFBackground And Aims: Femoral artery access is widely used despite recent increase in radial access for percutaneous coronary interventions (PCI). Femoral artery closure devices are used to shorten vascular closure time and reduce bleeding. We sought to examine sex-based outcomes of femoral artery vascular closure devices (VCD) in patients undergoing PCI.
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