Search Results (30)

Background/Objectives: Performing cardiopulmonary resuscitation (CPR) is cognitively demanding, often requiring helpers to perform cognitive and manual tasks simultaneously. While the human brain primarily switches between tasks rather than processing them simultaneously, it remains unclear whether performing repetitive, monotonous manual tasks, such as chest compressions, affects cognitive performance. This study aimed to assess the impact of chest compressions on mental arithmetic performance. Methods: In a randomized crossover trial, healthy participants trained in advanced life support (physicians, nurses, and paramedics) completed the Paced Auditory Serial Addition Test (PASAT) under two conditions: with or without performing chest compressions on a manikin. The primary outcome was the number of correct PASAT answers. Secondary outcomes included workload assessment using the NASA Task Load Index (TLX) and chest compression (CC) performance. The trial was registered at clinicaltrials.gov and approved by the local ethics committee. Results: Thirty-eight participants were included. The number of correct PASAT responses was significantly lower during chest compressions compared to the control (36.5 vs. 41; p < 0.01). NASA TLX values were significantly higher in the chest compression condition, indicating increased perceived workload. Chest compression performance showed statistically significant differences between a phase of just chest compressions and during the PASAT, especially increased levels of incomplete recoil. Conclusions: This study demonstrates that even a simple repetitive motor task like chest compressions impairs cognitive task performance significantly. Furthermore, multitasking was shown to decrease chest compression quality. These findings strongly highlight the importance of effective task allocation and minimizing multitasking during CPR to optimize performance and thereby patient outcomes. Full article

In light of the current issue of commercial and modified drones frequently intruding into sensitive locations such as airports, this paper proposes the use of quadrotor drones equipped with a launch device for interception. For an “X”-shaped quadrotor drone equipped with a two-degree-of-freedom gimbal launch device, dynamic, control, and ballistic models are constructed to analyze the impact of single-shot firing on the drone’s attitude and the factors affecting accuracy in rapid-fire scenarios. Simulation results indicate that downward firing has the highest shooting accuracy and is suitable for counter-drone missions. For single-shot firing, lateral downward firing compared to frontal firing can effectively reduce attitude and position changes, which is beneficial for engaging stationary targets. In the case of rapid fire, control of the firing interval is crucial for accuracy; a larger firing interval can significantly enhance shooting precision. When firing small payloads in rapid succession, vertical downward firing has the highest accuracy, while lateral firing results in a larger distribution radius of the impact points. To improve shooting accuracy, frontal firing is recommended. Future research will further explore the dynamic response of drones under different firing conditions and develop more advanced control strategies to enhance their practical performance and reliability. Full article

We report the results of a systematic investigation of localized dynamical states in the model of a one-dimensional magnetic wire, which is based on the Landau–Lifshitz–Gilbert (LLG) equation. The dissipative term in the LLG equation is compensated by the parametric drive imposed by the external AC magnetic field, which is uniformly applied perpendicular to the rectilinear wire. The existence and stability of the localized states is studied in the plane of the relevant control parameters, namely, the amplitude of the driving term and the detuning of its frequency from the parametric resonance. With the help of systematically performed simulations of the LLG equation, the existence and stability areas are identified in the parameter plane for several species of the localized states: stationary single- and two-soliton modes, single and double breathers, drifting double breathers with spontaneously broken inner symmetry, and multisoliton complexes. Multistability occurs in this system. The breathers emit radiation waves (which explains their drift caused by the spontaneous symmetry breaking, as it breaks the balance between the recoil from the waves emitted to left and right), while the multisoliton complexes exhibit cycles of periodic transitions between three-, five-, and seven-soliton configurations. Dynamical characteristics of the localized states are systematically calculated too. These include, in particular, the average velocity of the asymmetric drifting modes, and the largest Lyapunov exponent, whose negative and positive values imply that the intrinsic dynamics of the respective modes is regular or chaotic, respectively. Full article

Background: This study aims to provide a comprehensive overview of speckle tracking echocardiography (STE) findings in patients diagnosed with acromegaly, exploring a potential application for the differential diagnosis of cardiac hypertrophy and guiding clinicians in patient management. To our knowledge, this is the first review showcasing changes in the bull’s-eye pattern in myocardial function after acromegaly treatment, suggesting a possible pattern in this aetiology of left ventricular hypertrophy. Methods: A review of PubMed articles using the search term “speckle tracking echocardiography acromegaly” yielded 11 relevant papers published between 2017 and 2023. The final analysis evaluated each paper’s substantial value and summarised pertinent information. A clinical case of myocardial strain changes before and after pharmacological and neurosurgical treatment is also described. Results: The 11 analysed papers, with patient groups ranging from 19 to 50 individuals, revealed varying results in STE parameters between acromegalic and control groups. Left ventricular strain parameters were commonly assessed, showing discrepancies in different studies. Notably, the MAGYAR-Path Study emphasised left ventricular twist and radial strain abnormalities in acromegaly patients. Furthermore, the interplay between acromegaly and diabetes influenced myocardial function. Drug treatment with somatostatin receptor ligands demonstrated a favourable impact on left ventricular systolic function. The case study we describe in this manuscript showed changes in the posterior basal LV segment, which may be a specific pattern of acromegaly remodelling. Somatostatin therapy and neurosurgery led to the normalisation of global longitudinal strain (GLS) and improvement in myocardial work, as well as improved diastolic function, including enhanced left atrial strain (LAS) as well as a visible elastic recoil sign (ERS). Conclusions: While the available literature on STE in acromegaly is limited, our analysis suggests potential applications in differentiating hypertrophy aetiologies and monitoring cardiac function post-treatment. The results underscore the need for more interdisciplinary research to optimise patient management. The bull’s-eye pattern with posterior basal segment strain impairment we describe may be used to differentiate this entity. Full article

The inherent instability of laser welding, particularly keyhole instability, poses significant challenges in industrial applications, leading to defects such as porosities that compromise weld quality. Various forces act on the keyhole and molten pool during laser welding, influencing process stability. These forces are categorized into those promoting keyhole opening and penetration (e.g., recoil pressure) and those promoting keyhole collapse (e.g., surface tension, Darcy’s damping forces), increasing instability and defect likelihood. This paper provides a comprehensive instability analysis to uncover key factors affecting keyhole and process instability, presenting future avenues for improving laser welding stability. Using a novel numerical method for simulating laser spot welding on aluminum with COMSOL Multiphysics 5.6, we investigated the effect of laser pulse shaping on keyhole and process instability. Our analysis focused on keyhole morphology, fluid flow behaviour, and force analysis. The results indicated that the curvature effect, Marangoni effect, and Darcy’s damping force are primary contributors to instability, with the curvature effect and Darcy’s damping force being the most dominant. Additionally, erratic and high-velocity magnitudes induce intense fluid flow behaviour, exacerbating keyhole instability. Moreover, single/quadruple peak triangular and variant rectangular ramp-down pulse shapes produced the least instability, while multi-pulse rectangular shapes exhibited intense instability. It was found that combining triangular/rectangular pulse shapes can reduce force and keyhole instability by smoothing spontaneous force spikes, resulting in a more stabilized welding process. Controlling fluid flow and abrupt force changes with appropriate pulse shaping is key to defect-free welded products. Full article

Gastric perforation refers to the complete rupture of the gastric wall, leading to the extravasation of gastric contents into the thoracic cavity or peritoneum. Without timely intervention, the expulsion of gastric contents may culminate in profound discomfort, exacerbating the inflammatory process and potentially triggering perilous sepsis. In clinical practice, surgical suturing or endoscopic closure procedures are commonly employed. Magnetic-driven microswarms have also been employed for sealing gastrointestinal perforation. However, surgical intervention entails significant risk of bleeding, while endoscopic closure poses risks of inadequate closure and the need for subsequent removal of closure clips. Moreover, the efficacy of microswarms is limited as they merely adhere to the perforated area, and their sealing effect diminishes upon removal of the magnetic field. Herein, we present a Fe&Mg@Lard-Paraffin micromotor (LPM) constructed from a mixture of lard and paraffin coated with magnesium (Mg) microspheres and iron (Fe) nanospheres for sutureless sealing gastric perforations. Under the control of a rotating magnetic field, this micromotor demonstrates precise control over its movement on gastric mucosal folds and accurately targets the gastric perforation area. The phase transition induced by the high-frequency magnetothermal effect causes the micromotor composed of a mixed oil phase of lard and paraffin to change from a solid to a liquid phase. The coated Mg microspheres are subsequently exposed to the acidic gastric acid environment to produce a magnesium protonation reaction, which in turn generates hydrogen (H₂) bubble recoil. Through a Mg-based micropower traction, part of the oil phase could be pushed into the gastric perforation, and it would then solidify to seal the gastric perforation area. Experimental results show that this can achieve long-term (>2 h) gastric perforation sealing. This innovative approach holds potential for improving outcomes in gastric perforation management. Full article

Background: Chronic limb-threatening ischaemia can be a debilitating disease and may result in limb amputation if untreated. Atherosclerotic disease of the infra-popliteal arteries is particularly challenging to treat due to the small caliber of the vessels and the heavy burden of atherosclerotic plaque. Percutaneous transluminal angioplasty is the conventional first-line approach and is advantageous due to its minimal invasiveness, repeatability, and cost-effectiveness but is limited by high rates of elastic recoil, dissection, and short- to mid-term re-stenosis. Methods: This review analyses the growing body of published and presented clinical data from multiple randomised controlled trials that have investigated the role of coronary drug-eluting stents in the treatment of infrapopliteal disease. Results: Coronary drug-eluting stents demonstrate superior primary patency compared with angioplasty and/or bare metal stenting alone but are limited to application in short-segment disease and have not been widely adopted due to the nature of the permanent implant. Conclusions: Newer devices like drug-eluting resorbable scaffolds are promising as they allow the restoration of vessel wall vasomotion without a residual foreign body and can be used to treat longer, complex lesions. Full article

The ubiquitous pollution by antibiotics and heavy metal ions has posed great threats to human health and the ecological environment. Therefore, we developed a self-propelled tubular micromotor based on natural fibers as an active heterogeneous catalyst for antibiotic degradation and adsorbent for heavy metal ions in soil/water. The prepared micromotors can move in the presence of hydrogen peroxide (H₂O₂) through a bubble recoil mechanism. The MnO₂ NPs and MnFe₂O₄ NPs loaded on the hollow fibers not only enabled self-driven motion and magnetic control but also served as activators of peroxymononsulfate (PMS) and H₂O₂ to produce active free radicals SO₄^•− and •OH. Benefiting from the self-propulsion and bubble generation, the micromotors can effectively overcome the disadvantage of low diffusivity of traditional heterogeneous catalysts, achieving the degradation of more than 90% TC in soil within 30 min. Meanwhile, due to the large specific surface area, abundant active sites, and strong negative zeta potential, the micromotors can effectively adsorb heavy metal ions in the water environment. In 120 min, self-propelled micromotors removed more than 94% of lead ions, an increase of 47% compared to static micromotors, illustrating the advantages of on-the-fly capture. The prepared micromotors with excellent catalytic performance and adsorption capacity can simultaneously degrade antibiotics and adsorb heavy metal ions. Moreover, the magnetic response enabled the micromotors to be effectively separated from the system after completion of the task, avoiding the problem of secondary pollution. Overall, the proposed micromotors provide a new approach to the utilization of natural materials in environmental applications. Full article

Acute respiratory distress syndrome (ARDS) is associated with a heterogeneous pattern of injury throughout the lung parenchyma that alters regional alveolar opening and collapse time constants. Such heterogeneity leads to atelectasis and repetitive alveolar collapse and expansion (RACE). The net effect is a progressive loss of lung volume with secondary ventilator-induced lung injury (VILI). Previous concepts of ARDS pathophysiology envisioned a two-compartment system: a small amount of normally aerated lung tissue in the non-dependent regions (termed “baby lung”); and a collapsed and edematous tissue in dependent regions. Based on such compartmentalization, two protective ventilation strategies have been developed: (1) a “protective lung approach” (PLA), designed to reduce overdistension in the remaining aerated compartment using a low tidal volume; and (2) an “open lung approach” (OLA), which first attempts to open the collapsed lung tissue over a short time frame (seconds or minutes) with an initial recruitment maneuver, and then stabilize newly recruited tissue using titrated positive end-expiratory pressure (PEEP). A more recent understanding of ARDS pathophysiology identifies regional alveolar instability and collapse (i.e., hidden micro-atelectasis) in both lung compartments as a primary VILI mechanism. Based on this understanding, we propose an alternative strategy to ventilating the injured lung, which we term a “stabilize lung approach” (SLA). The SLA is designed to immediately stabilize the lung and reduce RACE while gradually reopening collapsed tissue over hours or days. At the core of SLA is time-controlled adaptive ventilation (TCAV), a method to adjust the parameters of the airway pressure release ventilation (APRV) modality. Since the acutely injured lung at any given airway pressure requires more time for alveolar recruitment and less time for alveolar collapse, SLA adjusts inspiratory and expiratory durations and inflation pressure levels. The TCAV method SLA reverses the open first and stabilize second OLA method by: (i) immediately stabilizing lung tissue using a very brief exhalation time (≤0.5 s), so that alveoli simply do not have sufficient time to collapse. The exhalation duration is personalized and adaptive to individual respiratory mechanical properties (i.e., elastic recoil); and (ii) gradually recruiting collapsed lung tissue using an inflate and brake ratchet combined with an extended inspiratory duration (4–6 s) method. Translational animal studies, clinical statistical analysis, and case reports support the use of TCAV as an efficacious lung protective strategy. Full article

The actinium-225 (²²⁵Ac) radioisotope exhibits highly attractive nuclear properties for application in radionuclide therapy. However, the ²²⁵Ac radionuclide presents multiple daughter nuclides in its decay chain, which can escape the targeted site, circulate in plasma, and cause toxicity in areas such as kidneys and renal tissues. Several ameliorative strategies have been devised to circumvent this issue, including nano-delivery. Alpha-emitting radionuclides and nanotechnology applications in nuclear medicine have culminated in major advancements that offer promising therapeutic possibilities for treating several cancers. Accordingly, the importance of nanomaterials in retaining the ²²⁵Ac daughters from recoiling into unintended organs has been established. This review expounds on the advancements of targeted radionuclide therapy (TRT) as an alternative anticancer treatment. It discusses the recent developments in the preclinical and clinical investigations on ²²⁵Ac as a prospective anticancer agent. Moreover, the rationale for using nanomaterials in improving the therapeutic efficacy of α-particles in targeted alpha therapy (TAT) with an emphasis on ²²⁵Ac is discussed. Quality control measures in the preparation of ²²⁵Ac-conjugates are also highlighted. Full article

Nanoparticles of various materials were proposed as carriers of nuclides in targeted alpha particle therapy to at least partially eliminate the nuclear recoil effect causing the unwanted release of radioactive progeny originating in nuclear decay series of so-called in vivo generators. Here, we report on the study of ²¹¹Pb and ²¹¹Bi recoils release from the ²²³Ra surface-labelled TiO₂ nanoparticles in the concentration range of 0.01–1 mg/mL using two phase separation methods different in their kinetics in order to test the ability of progeny resorption. We have found significant differences between the centrifugation and the dialysis used for labelled NPs separation as well as that the release of ²¹¹Pb and ²¹¹Bi from the nanoparticles also depends on the NPs dispersion concentration. These findings support our previously proposed recoils-retaining mechanism of the progeny by their resorption on the NPs surface. At the 24 h time-point, the highest overall released progeny fractions were observed using centrifugation (4.0% and 13.5% for ²¹¹Pb and ²¹¹Bi, respectively) at 0.01 mg/mL TiO₂ concentration. The lowest overall released fractions at the 24 h time-point (1.5% and 2.5% for ²¹¹Pb and ²¹¹Bi respectively) were observed using dialysis at 1 mg/mL TiO₂ concentration. Our findings also indicate that the in vitro stability tests of such radionuclide systems designed to retain recoil-progeny may end up with biased results and particular care needs to be given to in vitro stability test experimental setup to mimic in vivo dynamic conditions. On the other hand, controlled and well-defined progeny release may enhance the alpha-emitter radiation therapy of some tumours. Full article

The deepwater drilling riser is a very important and vulnerable connection between an offshore platform and subsea wellhead. Under some certain complex marine environment and operating conditions, the offshore platform may drift beyond the safe limitations or be driven away rapidly. In order to protect the safety of the platform, personnel and equipment, it is necessary to implement the emergency disconnection of the drilling riser. Since the riser is stretched under a normal connection, the riser will perform a recoil response under the combined effect of elastic potential energy and drilling fluid (mud) discharge frictional resistance after the emergency disconnection. There are complex mechanical mechanisms, influencing factors and difficult safety control problems in the recoil control process. Therefore, effectively controlling the recoil response of the deepwater drilling riser after emergency release has become one of the technical difficulties faced by deepwater drilling. The drilling mud discharge frictional resistance and tensioning force are important factors affecting the recoil response. It is necessary to develop a more general dynamic recoil model for the riser that considers the actual conditions of drilling mud discharge, floating platform motion and nonlinear tensioner factors. This paper introduces the research progress on the recoil analysis and control technology of the deepwater drilling riser, including the discharge, mechanical analysis model, the top tensioner system and control method of the recoil response, which provides a reference for future research on recoil response analyses and design of deepwater drilling risers. Full article

Compared to magnetorheological fluid, magnetorheological gel has better anti-settling performance and stability. Therefore, magnetorheological gel is suitable for devices that can meet operational requirements in all aspects after long-term storage, such as the anti-recoil application of weapons. To study this in-depth, the mechanism of the influence of magnetorheological gel micro-magnetic-mechanical properties on the macro-output damping mechanics of the damper, a parallel plate model of the mixed flow mode composed of Couette shear flow and Poiseuille pressure flow was established. The theoretical analysis was of the output damping of the damper. Finally, the controllability of the damper under impact load employed magnetorheological gel was preliminarily analyzed. The results indicate that the damping coefficient of the damper increases with the increase of dynamic viscosity ${\eta }_B$ of the magnetorheological gel, piston effective cross-sectional area $A_P$, magnetic pole $L$, and Bingham coefficient $Bi$. Magnetorheological damper has controllability under impact load and can reach a wide controllable range under the condition under small magnetic field ranging from 0 mT to 131 mT. Full article

Williams–Beuren syndrome (WS) results from the deletion of 25–27 coding genes, including elastin (ELN), on human chromosome 7q11.23. Elastin provides recoil to tissues; emphysema and chronic obstructive pulmonary disease have been linked to its destruction. Consequently, we hypothesized that elastin insufficiency would predispose to obstructive features. Twenty-two adults with WS (aged 18–55) and controls underwent pulmonary function testing, 6 min walk, and chest computed tomography (CT). Lung and airspace dimensions were assessed in Eln^+/− and control mice via microCT and histology. The forced expiratory volume in 1 s (FEV₁) and the ratio of FEV₁ to forced vital capacity (FVC) were lower in adults with WS (p < 0.0001 and p < 0.05, respectively). The FEV₁/FVC ratio was more frequently below the lower limit of normal in cases (p < 0.01). The ratio of residual volume to total lung capacity (RV/TLC, percent predicted) was higher in cases (p < 0.01), suggesting air trapping. People with WS showed reduced exercise capacity (p < 0.0001). In Eln^+/− mice, ex vivo lung volumes were increased (p < 0.0001), with larger airspaces (p < 0.001). Together these data show that elastin insufficiency impacts lung physiology in the form of increased air trapping and obstruction, suggesting a role for lung function monitoring in adults with WS. Full article

The discovery of He retentivity in magnetite has opened up the use of the magnetite (U-Th)/He method as a thermochronometer to date the exhumation of mafic and ultramafic rocks, and also as a chronometer to date magnetite crystallization during serpentinization. However, published He diffusion data reveal more complex behavior than expected. To resolve this issue and generalize the understanding of He retention in magnetite, we conducted a multiscale theoretical study. We investigated the impact of natural point-defects (i.e., vacancies unrelated to radiation damage) and defects associated with radiation damage (i.e., vacancies and recoil damage that form amorphous zones) on He diffusion in magnetite. The theoretical results show that He diffusion is purely isotropic, and that defect-free magnetite is more He diffusive than indicated by experimental data on natural specimen. Interestingly, the obtained theoretical trapping energy of vacancies and recoil damage are very similar to those obtained from experimental diffusion data. These results suggest that He diffusion in magnetite is strongly controlled by the presence of vacancies and radiation damage, even at very low damage dose. We propose that, when using magnetite (U-Th)/He thermochronometry, the impact of vacancies and radiation damage on He retention behavior should be integrated. Full article