Safety Margin Research Articles

Tracheal hyperallometry and spatial constraints in a large beetle

Insects exchange respiratory gases with their environment through their gas-filled tracheal system, a branched tracheal tree extending from segmental openings and terminating at fine tissue penetrating tracheoles. It was shown that the tracheal volume increases hyperallometrically with insect body size (Mb), both interspecifically and across developmental stages. In this study, we used the sixfold Mb variation in adult Batocera rufomaculata(Cerambicidae; Coleoptera) examining the allometry of adult tracheal volume (Vtr). We further explored the effect of sex and sexual maturity on tracheal gas conductance, testing the hypotheses that (i) larger body size and (ii) egg volume in gravid females would result in lower safety margins for tracheal oxygen transport due to structural restriction. We report a hyperallometric tracheal growth in both sexes of adult B. rufomaculata(mean mass exponent of 1.42 ± 0.09), similar in magnitude to previously reported values. Tracheal gas conductance was independent of Mb and reproductive state, but was significantly higher in females compared with males. We suggest that females may have pre-adapted a higher tracheal conductance required for the higher flight power output while gravid. Lack of compliant air sacs and rigid trachea may explain how gravid females retain their Vtr. However, we show that Vtr outgrows thoracic dimensions with increased B. rufomaculatasize. Hyperallometric growth of the giant cerambycid thoracic trachea could explain the previously reported hypometric scaling of flight muscles in B. rufomaculata, and the compromised long-distance flight performance of larger compared with smaller conspecifics.

Redundancy and reliability levels of post-tensioned and grouted concrete cross-section in case of tendon failure

Since the 1960 s and 1970 s, the prestressing steel used on post-tensioned concrete (PTC) bridges has been known to be susceptible to stress corrosion cracking (SCC). This can result in brittle rupture of the prestressing steel. Objective of this study is to evaluate the reliability levels achieved with assessment method developed for verifying crack behaviour before failure in cross-section of PTC bridges with cross-section loss of prestressing steel. Additionally, the study aims to investigate of tendon loss on crack before failure behaviour. This paper applies a reliability analysis for methodology based on robustness analysis on crack before failure behaviour in PTC with deteriorating prestressing steel. The analysis involves examining cross-sections with various design criteria. The effects of choices made in designing the PTC structure are analysed and noted to have a significant impact on the safety margin of the structure, while the deterioration of prestressing steel does not significantly decrease the ductility of the cross-section if certain conditions are met. The use of stricter serviceability limit-state (SLS) criteria used in past design results the greater safety margin for the structure in the event of tendon loss, which therefore makes it beneficial for structural redundancy in the ultimate limit state (ULS).

Automated online safety margin (GLIOVIS) for glioma surgery model.

Glioblastoma is the most common type of primary brain malignancy and has a poor prognosis. The standard treatment strategy is based on maximal safe surgical resection followed by radiotherapy and chemotherapy. Surgical resection can be optimized by using 5-delta-aminolevulinic acid (5-ALA)-induced fluorescence, which is the current mainstay. Although 5-ALA-induced fluorescence has gained general acceptance, it is also limited by inter-observer variability and non-standardized fluorescence parameters. We present a new software for processing images analysis to better recognize the tumor infiltration margins using an intraoperative immediate safety map of 5-ALA-induced fluorescence. We tested this in a brain model using a commercial surgical exoscope. A dedicated software GLIOVIS (ACQuF-II, Advanced Colorimetry-based Quantification of Fluorescence) was designed for processing analysis of images taken on the Intraoperative Orbital Camera Olympus Orbeye (IOC) to determine the relative quantification of Protoporphyrin IX (5-ALA metabolite) fluorescence. The software allows to superpose the new fluorescence intensity map and the safety margins over the original images. The software was tested on gel-based brain models. Two surrogate models were developed: PpIX agarose gel-integrated in gelatin-based brain model at different scales (1:25 and 1:1). The images taken with the IOC were then processed using GLIOVIS. The intensity map and safety margins could be obtained for all available models. GLIOVIS for 5-ALA-guided surgery image processing was validated on various gelatin-based brain models. Different levels of fluorescence could be qualitatively digitalized using this technique. These results need to be further confirmed and corroborated in vivo and validated clinically in order to define a new standard of care for glioblastoma resection.

A Method for the Rapid Propagation of Emergency Event Notifications in a Long Vehicle Convoy

Convoys composed of autonomous vehicles could improve the transportation and freight industries in several ways. One of the avenues of improvement is in fuel efficiency, where the vehicles maintain a close following distance to each other in order to reduce air resistance by way of the draft effect. While close following distances improve fuel efficiency, they also reduce both the margin of safety and the system’s tolerance to disturbances in relative position. The system’s tolerance to disturbances is known as string stability, where the error magnitude either grows or decays as it propagates rearward through the convoy. One of the major factors in a system’s string stability is its delay in sending state updates to other vehicles, the most pertinent being a hard braking maneuver. Both external sensors and vehicle-to-vehicle communication standards have relatively long delays between peer vehicle state changes and the information being actionable by the ego vehicle. The system presented here, called the Convoy Vehicular Ad Hoc Network (Convoy VANET), was designed to reliably propagate emergency event messages with low delay while maintaining reasonable channel efficiency. It accomplishes this using a combination of several techniques, notably relative position-based retransmission delays. Our results using Network Simulator 3 (ns3) show the system propagating messages down a 20-vehicle convoy in less than 100 ms even with more than a 35% message loss between vehicles that are not immediately adjacent. These simulation results show the potential for this kind of system in situations where emergency information must be disseminated quickly in low-reliability wireless environments.

Squamous Cell Carcinoma of the Lip: Clinical Presentation and Management Outcome

Background: Squamous cell carcinoma (SCC) is the second most common amongst skin cancers, following the basal cell carcinoma. SCC of the lip carries relatively better prognosis if detected early and treated adequately. Public awareness about the significance of early presentation would help to improve the outcome of management. Objective: The current study was conducted to determine the clinical presentation of lip SCC and management outcome with surgery as the primary treatment modality. Methods: This descriptive study was carried out at the National Institute of Rehabilitation Medicine, Islamabad over a period of seven years. All patients who presented with lip SCCs during the study period were prospectively included in the study. Non-consenting patients were excluded. The lesions were excised with 1-2-cm palpable macroscopic safety margins. Results: Out of 37 patients, there were 28 (75.67%) males and 9 (24.32%) females. The ages ranged between 47-79 years with a mean of 59.91±9.17 years. Lower lip was the most commonly affected site (n=30; 81.08%). The duration of the lesions at first presentation varied from 6-13 months with a mean of 7.32±1.79 months. Majority (n=31; 83.78%), of the patients had early stage (stage I and II disease) whereas 6(16.21%) patients had stage III disease. The margin clearance rate after initial excision of the lesions was 91.89%. Karapandzic flap was employed as reconstructive tool among 15(40.54%) patients. The 5-year overall survival rate was 62.16%. Conclusion: Lip SCCs were found more frequently among males aged over 50 years. Lower lip was the commonest seat of lip SCCs. Surgical excision with recommended safety margins was associated with tumor free margins in 91.89% cases. Karapandzic flap was the most useful reconstructive tool. The 5-year overall survival rate was 62.16%.

Robust tracking of deformable anatomical structures with severe occlusions using deformable geometrical primitives

Background and objective:Surgical robotics tends to develop cognitive control architectures to provide certain degree of autonomy to improve patient safety and surgery outcomes, while decreasing the required surgeons’ cognitive load dedicated to low level decisions. Cognition needs workspace perception, which is an essential step towards automatic decision-making and task planning capabilities. Robust and accurate detection and tracking in minimally invasive surgery suffers from limited visibility, occlusions, anatomy deformations and camera movements. Method:This paper develops a robust methodology to detect and track anatomical structures in real time to be used in automatic control of robotic systems and augmented reality. The work focuses on the experimental validation in highly challenging surgery: fetoscopic repair of Open Spina Bifida. The proposed method is based on two sequential steps: first, selection of relevant points (contour) using a Convolutional Neural Network and, second, reconstruction of the anatomical shape by means of deformable geometric primitives. Results:The methodology performance was validated with different scenarios. Synthetic scenario tests, designed for extreme validation conditions, demonstrate the safety margin offered by the methodology with respect to the nominal conditions during surgery. Real scenario experiments have demonstrated the validity of the method in terms of accuracy, robustness and computational efficiency. Conclusions:This paper presents a robust anatomical structure detection in present of abrupt camera movements, severe occlusions and deformations. Even though the paper focuses on a case study, Open Spina Bifida, the methodology is applicable in all anatomies which contours can be approximated by geometric primitives. The methodology is designed to provide effective inputs to cognitive robotic control and augmented reality systems that require accurate tracking of sensitive anatomies.

SUBSTANTIATION OF SOLUTIONS TO INCREASE THE DURABILITY OF THE INNER ROWS OF STEEL TEETH OF ROLLER CONE BITS DURING DRILLING OF BOULDER-PEBBLE ROCK FORMATIONS

The article deals with issues concerning the increase in the productivity of roller bits when drilling soft and soft-medium rocks with inclusions of boulder-pebble formations by justifying solutions to increase the relative safety margin of steel teeth expressed in an increase of the impact strength of the material for making cones in combination with an increase in the geometry of steel teeth. The efficiency of the rock-crushing tool and, as a result, the destruction of rock during the entire drilling cycle, directly depends on the resource and durability of the elements of the roller bit. When drilling the upper intervals of deposits in the East Siberian region, composed of soft and soft-medium rocks with inclusions of boulder-pebble deposits, there is a problem of premature wear of the drill bit. Both PDC bits are subject to catastrophic wear due to chips and fractures of PDC cutters, as well as roller bits. The use of first-class roller bits with steel teeth leads to advanced wear, expressed by the scrapping of the teeth of the inner rows. This leads to a «hanging» of the bit and a loss of mechanical penetration speed. Based on this, the work provides recommendations for increasing the durability of steel teeth for first-class roller cone bits.

Analisis Break Even Point dan Margin of Safety Sebagai Alat Perencanaan Laba Pada Usaha Tahu Sumber Mulya Kota Bengkulu

The purpose of this study was to determine the application of BEP and MOS as a profit planning tool in the Usaha Tahu Sumber Mulya in Bengkulu city. The data collection method used is unstructured interviews and documentation with qualitative and quantitative analysis methods using Break Even Point analysis. The results of the research, BEP the contribution ratio per unit of tofu was 41% with a business profit rate of 35.3% with a margin of safety of 86.1%. While the where the contribution ratio per unit of tofu was 49.2% with a business profit level of 44.1%, the level of security or margin of safety in 2022 was 89.8%. The use of BEP and Safety stock calculation provides an overview of the Usaha Tahu Sumber Multa in Bengkulu City, you can see the BEP for tofu production and safety stock in the warehouse, this is so that the production process continues and obtain the desired profit .

Numerical study of the effect of helical fuel rod geometry on single-phase flow and heat transfer characteristics

Helical fuel is a promising nuclear fuel proposed to improve the core power density and safety margin. In this study, the effect of helical fuel rod geometry on single-phase flow and heat transfer characteristics in helical fuel annuli has been investigated. The volumetric energy source is applied to the fuel pin, and coupled walls are used at the coolant-cladding and cladding-fuel interfaces. The numerical method with SST k-ω turbulence model has been validated with the results of bare annulus. The flow field, fuel central temperature, friction factor, and the circumferential distribution of swirl intensity, heat flux and wall temperature are obtained based on the numerical simulation. The increase in R2/R1 will result in broadening transverse flow region, reducing the gradient of surface heat flux and wall temperature, lowering the maximum wall temperature, but increasing the fuel central temperature and has no significant effect on the friction resistance. The decrease of helical pitch increases the swirl intensity and friction factor, but worsens the heat transfer at the blade roots.

Evaluation of safety margins for cone beam CT-based adaptive prostate radiotherapy

Adaptive radiotherapy is characterized by the use of a daily imaging system, such as CBCT (Cone-Beam Computed Tomography) images to re-optimize the treatment based on the daily anatomy and position of the patient. By systematically re-delineating the Clinical Target Volume (CTV) at each fraction, target delineation uncertainty features a random component instead of a pure systematic. The goal of this work is to identify the random and systematic contributions of the delineation error and compute a new relevant Planning Target Volume (PTV) safety margin.169 radiotherapy sessions from 10 prostate cancer patients treated on the Varian ETHOS treatment system have been analyzed. Intra-patient and inter-patient delineation variabilities were computed in six directions, by considering the prostate as a rigid, non-rotating volume. By doing so, we were able to directly compare the delineations done by the physicians on daily CBCT images with the initial delineation done on the CT-sim and MRI, and sort them by direction using the polar coordinates of the points. The computed variabilities were then used to compute a PTV margin based on Van Herk margin recipe.The total margin computed with random and systematic delineation uncertainties was of 2.7, 2.4, 5.6, 4.8, 4.9 and 3.6 mm in the left, right, anterior, posterior, cranial and caudal directions, respectively.According to our results, the gain offered by the separation of the delineation uncertainty into systematic and random contributions due to the adaptive delineation process justifies a reduction of the PTV margin down to 3 to 5 mm in every direction.

Meta-Feature-Based Traffic Accident Risk Prediction: A Novel Approach to Forecasting Severity and Incidence

This study aims to improve the accuracy of predicting the severity of traffic accidents by developing an innovative traffic accident risk prediction model—StackTrafficRiskPrediction. The model combines multidimensional data analysis including environmental factors, human factors, roadway characteristics, and accident-related meta-features. In the model comparison, the StackTrafficRiskPrediction model achieves an accuracy of 0.9613, 0.9069, and 0.7508 in predicting fatal, serious, and minor accidents, respectively, which significantly outperforms the traditional logistic regression model. In the experimental part, we analyzed the severity of traffic accidents under different age groups of drivers, driving experience, road conditions, light and weather conditions. The results showed that drivers between 31 and 50 years of age with 2 to 5 years of driving experience were more likely to be involved in serious crashes. In addition, it was found that drivers tend to adopt a more cautious driving style in poor road and weather conditions, which increases the margin of safety. In terms of model evaluation, the StackTrafficRiskPrediction model performs best in terms of accuracy, recall, and ROC–AUC values, but performs poorly in predicting small-sample categories. Our study also revealed limitations of the current methodology, such as the sample imbalance problem and the limitations of environmental and human factors in the study. Future research can overcome these limitations by collecting more diverse data, exploring a wider range of influencing factors, and applying more advanced data analysis techniques.

Impact of magnet shape and material on the magnet stress

AbstractMagnet cracking is a common issue in external rotor motors. To investigate the causes of magnet cracking and propose solutions, the authors consider the effects of magnet shape, magnet and yoke material fit on the motor rotor magnets, perform a static analysis of the motor rotor. The simulation and test results show that the stress distribution of tile‐shaped magnets is better than that of rectangular magnets. The highest safety margin of 56.41% is achieved for the magnet and yoke material fit of DT4/N35(EH). The maximum force of the permanent magnet (PM) exceeds 22.38% of the stress limit when the material fit is DT4/SmCo28, which can lead to cracks in the PM. The results of this paper have important reference significance for the structural design of the external rotor motor and their safe and reliable operation.

Water status dynamics and drought tolerance of juvenile European beech, Douglas fir and Norway spruce trees as dependent on neighborhood and nitrogen supply.

To increase the resilience of forests to drought and other hazards, foresters are increasingly planting mixed stands. This requires knowledge about the drought response of tree species in pure- and mixed-culture neighborhoods. In addition, drought frequently interacts with continued atmospheric nitrogen (N) deposition. To disentangle these factors for European beech, Norway spruce and Douglas fir, we conducted a replicated three-factorial sapling growth experiment with three moisture levels, (high, medium and low), two N levels (high and ambient) and pure and mixed-culture neighborhoods. We measured biomass, stomatal conductance (GS), shoot water potential (at predawn: ΨPD, midday, and turgor loss point: ΨTLP), branch xylem embolism resistance (Ψ50), and minimum epidermal conductance (Gmin). The three species differed most with respect to Gmin (10-fold higher in beech than in the conifers), hydroscape area (larger in beech), and the time elapsed to reach stomatal closure (TΨGS90) and ΨTLP (TTLP; shorter in beech), while Ψ50 and ΨTLP were remarkably similar. Neighborhood (pure vs. mixed-culture) influenced biomass production, water status and hydraulic traits, notably GS (higher in Douglas fir, but lower in spruce and beech, in mixtures than pure culture), hydraulic safety margin (smaller for beech in mixtures), and TΨGS90 and TTLP (shorter for spruce in mixture). High N generally increased GS, but no consistent N effects on leaf water status and hydraulic traits were detected, suggesting that neighbor identity had a larger effect on plant water relations than N availability. We conclude that both tree neighborhood and N availability modulate the drought response of beech, spruce and Douglas fir. Species mixing can alleviate the drought stress of some species, but often by disadvantaging other species. Thus, our study suggests stabilizing and building resilience of production forests against a drier and warmer climate may depend primarily on the right species choice; species mixing can support the agenda.

Effects of axial compression ratio on seismic behavior of shallow‐buried rectangular stations: Hybrid simulation and quasi‐static test

AbstractIn the absence of experimental investigations on column members of underground structures, full‐scale column specimens were tested to explore the seismic behavior of shallow‐buried subway stations at various depths. The axial compression ratios of internal column specimens were set as 0.16, 0.33, and 0.40. Both hybrid simulations and quasi‐static tests were performed on the station columns. The hybrid simulations illustrated the drift demands of internal columns, while the load‐carrying capacity and deformation capacity were obtained from the quasi‐static tests. Hybrid simulations at low, moderate, and high‐intensity levels were conducted to study the seismic responses of shallow‐buried rectangular stations. The hybrid simulations suggest that the most severe damage occurred in the station when the axial compression ratio of the tested column reached 0.40. Central columns suffered severe stiffness deterioration under high‐level earthquake excitation, especially in stations at greater depths. Meanwhile, the quasi‐static test results indicate that the ultimate load of the central columns increases with increasing axial compression, but this leads to a significant decrease in the ductility of columns. Besides, the sectional analysis results show that the central columns are prone to tension‐controlled failure, and the safety margin for flexural response deteriorates with an increasing axial compression ratio. The test results indicate that shallow‐buried rectangular stations are susceptible to flexure‐controlled structural failure when their central columns possess a relatively low axial compression ratio and a high shear span‐to‐depth ratio. The failure mechanism of station columns is revealed by both the hybrid simulations and quasi‐static tests, and the findings from the full‐scale tests are beneficial for the practical design of shallow‐buried rectangular stations.

Comprehensive structural and functional analysis of Patuletin as a potent inhibitor of SARS-CoV-2 targeting the RNA-dependent RNA polymerases

In the pursuit of identifying effective inhibitors against SARS-CoV-2, we conducted a detailed investigation into the binding interactions and inhibitory potential of Patuletin targeting the RNA-Dependent RNA Polymerase (RdRp), comparing it with the well-known anti-RdRp agent, Remdesivir. Superimposition molecular docking studies uncovered a high degree of similarity in binding modes between Patuletin and Remdesivir within the active site of the RdRp. MD simulations (RMSD, RMSF, RG, SASA, hydrogen bonding) over a 200 ns trajectory provided valuable insights into the binding and interactions of Patuletin and RdRp comparing Remdesivir. These simulations validated the correct binding and optimum changes in both energetic and dynamic aspects, confirming the stability of the Patuletin-RdRp complex comparing the Remdesivir-RdRp complex. Further, the MM-GBSA technique revealed favorable binding energies, with Patuletin displaying a significantly lower value (-4.24 kcal/mol) compared to Remdesivir (-2.15 kcal/mol), affirming the robustness of Patuletin-RdRp binding. The MM-GBSA analysis additionally examined the binding energetic components, revealing a high degree of similarity between Patuletin and Remdesivir. 3D binding interactions were investigated through ProLIF and PLIP studies reinforcing the stable binding observed in the simulations. Principal component analysis of trajectories (PCAT) studies were employed to discern coordinated motions within the evaluated systems, providing additional perspectives on the dynamic behavior of the Patuletin-RdRp complex. In vitro assays demonstrated Patuletin's exceptional inhibitory potency against the RdRp, with an IC50 of 248 nM, far surpassing Remdesivir, which exhibited an IC50 of 20 µM. Interestingly, the in vitro IC50 against SARS-CoV-2 values further supported the superior efficacy of Patuletin (0.476 µg/ml) over Remdesivir (10.86 µg/ml). Furthermore, the viral selectivity index (SI) values highlighted the remarkable safety margin of Patuletin (SI: 790.76) compared to Remdesivir (SI: 5.87), underscoring the potential of Patuletin as a safer and more potent therapeutic agent against SARS-CoV-2. In conclusion, our comprehensive analysis presents Patuletin as a promising candidate for further exploration as a potent inhibitor of SARS-CoV-2 RdRp, offering valuable insights for the development of effective anti-COVID-19 therapies.

Giant pretibial cellular fibrous histiocytoma colliding with an epidermal cyst

Histiocytomas are common benign tumors of the skin. In contrast, giant histiocytomas are a rarity. We report a 43-year-old male patient, who presented with a 7 × 6 cm large firm tumor on his left lower leg. This was a long-standing lesion, but within the last three months, the tumor developed an exophytic nodule. A skin biopsy revealed an atypical spindle-cell tumor. We decided to perform a complete excision with a safety margin. Complete histopathological analysis confirmed the diagnosis of a collision tumor composed of a cellular fibrous histiocytoma and an epidermal cyst. The resulting defect was temporarily closed by vacuum-assisted closure before eventually a meshed split skin graft was transplanted. Proliferating fibrohistiocytic lesions should be surgically removed, and a careful histopathologic analysis is necessary to avoid delayed diagnosis of possible malignant lesions.

Testing the shock protection performance of Type I construction helmets using impactors of different masses.

Wearing protective helmets is an important prevention strategy to reduce work-related traumatic brain injuries. The existing standardized testing systems are used for quality control and do not provide a quantitative measure of the helmet performance. To analyze the failure characterizations of Type I industrial helmets and develop a generalized approach to quantify the shock absorption performance of Type I industrial helmets based on the existing standardized setups. A representative basic Type I construction helmet model was selected for the study. Top impact tests were performed on the helmets at different drop heights using two different impactor masses (3.6 and 5.0 kg). When the helmets were impacted with potential impact energies smaller than the critical potential impact energy values, there was a consistent relationship between the peak impact force and the potential impact energy. When the helmets were impacted under potential impact energies greater than the critical potential impact energy values, the peak impact forces increased steeply with increasing potential impact energy. A concept of safety margin for construction helmets based on potential impact energy was introduced to quantify the helmets' shock absorption performance. The proposed method will help helmet manufacturers improve their product quality.

Primary cutaneous mucinous carcinoma in a periorbital lesion: two case reports and literature review.

Primary cutaneous mucinous carcinoma (PCMC) is a rare malignancy of the sweat glands that most commonly affects the periorbital area. It is characterized by slow growth over a prolonged period, and its morphology can be easily confused with a benign tumor, such as an epidermal cyst. Consequently, many patients experience recurrence after undergoing multiple resections. However, there are few reports concerning the surgical management of PCMC. We present two cases of PCMC originating in the periorbital area. The first case involved a 76-year-old man with a mass measuring 3.0× 1.5 cm that had been increasing in size. The second case was a 61-year-old man with two masses, each measuring 1.0× 1.0 cm, that were also growing. Both patients underwent wide excision with a 5-mm safety margin, which was determined based on the widest view of the cross-section of the mass on the magnetic resonance imaging. Subsequently, based on the intraoperative frozen biopsy results, both patients underwent additional excision with a 5-mm safety margin in only one direction. This report shows that, when determining the surgical margin of PCMC in periorbital area, employing imaging modalities and intraoperative frozen biopsies can be helpful for narrowing the surgical margin.

A flexible, reusable and adjustable high-performance energy absorption system inspired by interlocking suture structures

Energy absorption systems play a very important role in impact protection under complex load conditions. However, traditional protective structures cannot adjust the mechanical properties on demand to accommodate variable load characteristics once manufactured. Therefore, inspired by the superior compression resistance of the diabolical ironclad beetle, a modular energy absorption system is developed by combining the efficient mechanical properties of thin-walled tubes and the robust connectivity of interlocking suture structures, which can be easily assembled from only bio-inspired tubes without external constraints. FEM simulations were performed to systematically investigate the static and dynamic mechanical properties of the developed system, and its crushing performance was demonstrated experimentally. Additionally, the influence of geometric parameters on the mechanical properties of the system has been investigated, and the insensitivity of secondary geometrical parameters and assembly defects has been verified, which shows that the system has a certain safety margin to avoid catastrophic accidents caused by fabrication defects. Moreover, the system exhibits excellent reusability under multi-impact load environments and its energy absorption capacity does not degrade after the primary impact. Furthermore, the system exhibits good designability thanks to the discrete modular structures, its mechanical properties can be tuned by stiffness design without affecting the energy absorption capacity, and its specific energy absorption can be effectively improved by lightweight design. This study provides a novel design strategy for the protection system applied in multiple complex environments.

Is Stent Retraction to ReLieve Arterial Cerebral VaSospasm Caused by SAH (Stent-ReLACSS) Using PRELAX the Long-awaited Solution for Treatment of Posthemorrhagic Cerebral Vasospasm? : Treatment of Posthemorrhagic Cerebral Vasospasm with PRESET and PRELAX: Technical Aspects, Efficacy, and Safety Margins in aCase Series.

Recent observational studies have indicated the efficacy of stent retriever devices for the treatment of posthemorrhagic cerebral vasospasm (CVS), both by deployment and on-site withdrawal into the microcatheter (stent angioplasty, SA) and deployment followed by retraction through the target vessel similar to thrombectomy (Stent Retraction to reLieve Arterial Cerebral vaSospasm caused by SAH, Stent-ReLACSS). This article reports the findings with each application of pRESET and pRELAX in the treatment of CVS. We retrospectively enrolled 25patients with severe CVS following aneurysmal subarachnoid hemorrhage. For the SA group, astent retriever or apRELAX was temporarily deployed into anarrow vessel segment and retrieved into the microcatheter after 3 min. For the Stent-ReLACSS group, apRELAX was temporarily deployed into anarrow vessel and pulled back unfolded into the internal carotid artery. If intra-arterial vasodilators were administered, they were given exclusively after mechanical vasospasmolysis to maximize the effectiveness of the stent treatment. In this study fifteen patients and 49vessels were treated with SA. All were technically successful without periprocedural complications; however, 8/15patients (53.3%) required additional treatment of the CVS. A total of 10 patients and 23 vessel segments were treated with Stent-ReLACSS. All maneuvers were technically successful without periprocedural complications and all vessels showed significant angiographic improvement. No recurrent CVS requiring further endovascular treatment occurred in-hospital, and neither territorial ischemia in the treated vessels nor vascular injury were observed in follow-up angiography. Based on the presented data it appears that Stent-ReLACSS with pRELAX does not pose any additional risks when used to treat CVS and might be superior to SA, especially concerning mid-term and long-term efficacy. The mechanism of action may be an effect on the endothelium rather than mechanical vasodilation. As many patients with CVS are diagnosed too late, prophylactic treatment of high-risk patients (e.g., poor grade, young, female) is potentially viable.