scholarly journals The Influence of Headform/Helmet Friction on Head Impact Biomechanics in Oblique Impacts at Different Tangential Velocities

2021 ◽  
Vol 11 (23) ◽  
pp. 11318
Author(s):  
Óscar Juste-Lorente ◽  
Mario Maza ◽  
Mathieu Piccand ◽  
Francisco J. López-Valdés
Keyword(s):  
Real World ◽  
Normal Component ◽  
Tangential Velocity ◽  
Linear Acceleration ◽  
Velocity Variation ◽  
Low Friction ◽  
Motorcycle Helmet ◽  
Impact Biomechanics ◽  
Oblique Impacts ◽  
The Impact

Oblique impacts of the helmet against the ground are the most frequent scenarios in real-world motorcycle crashes. The combination of two factors that largely affect the results of oblique impact tests are discussed in this work. This study aims to quantify the effect of the friction at the interface between the headform and the interior of a motorcycle helmet at different magnitudes of tangential velocity. The helmeted headform, with low friction and high friction surface of the headform, was dropped against three oblique anvils at different impact velocities resulting in three different magnitudes of the tangential velocity (3.27 m/s, 5.66 m/s, 8.08 m/s) with the same normal component of the impact velocity (5.66 m/s). Three impact directions (front, left-side and right-side) and three repetitions per impact condition were tested resulting in 54 impacts. Tangential velocity variation showed little effect on the linear acceleration results. On the contrary, the rotational results showed that the effect of the headform’s surface depends on the magnitude of the tangential velocity and on the impact direction. These results indicate that a combination of low friction with low tangential velocities may result into underprediction of the rotational headform variables that would not be representative of real-world conditions.

The range of bicycle helmet performance at real world impact locations

2021 ◽  
pp. 175433712110577
Author(s):  
Ann R Harlos ◽  
Steven Rowson
Keyword(s):  
Real World ◽  
Test Line ◽  
Linear Acceleration ◽  
The United States ◽  
Consumer Product Safety Commission ◽  
Bicycle Helmets ◽  
Impact Location ◽  
Increased Risk ◽  
Post Hoc ◽  
The Impact

In the United States, all bicycle helmets must comply with the standard created by the Consumer Product Safety Commission (CPSC). In this standard, bike helmets are only required to by tested above an established test line. Unregulated helmet performance below the test line could pose an increased risk of head injury to riders. This study quantified the impact locations of damaged bike helmets from real-world accidents and tested the most commonly impacted locations under CPSC bike helmet testing protocol. Ninety-five real-world impact locations were quantified. The most common impact locations were side-middle (31.6%), rear boss-rim (13.7%), front boss-rim (9.5%), front boss-middle (9.5%), and rear boss-middle (9.5%). The side-middle, rear boss-rim, and front boss (front boss-middle and front boss-rim regions combined) were used for testing. Two of the most commonly impacted regions were below the test line (front boss-rim and rear boss-rim). Twelve purchased helmet models were tested under CPSC protocol at each location for a total of 36 impacts. An ANOVA test showed that impact location had a strong influence on the variance of peak linear acceleration (PLA) ( p = 0.002). A Tukey HSD post hoc test determined that PLA at the side-middle (214.9 ± 20.8 g) and front boss (228.0 ± 39.6 g) locations were significantly higher than the PLA at the rear boss-rim (191.5 ± 24.2 g) location. The highest recorded PLA (318.8 g) was at the front boss-rim region. This was the only test that exceeded the 300 g threshold. This study presented a method for quantifying real-world impact locations of damaged bike helmets. Higher variance in helmet performance was found at the regions on or below the test line than at the region above the test line.

Influence of the Leakage Flow Tangential Velocity on the Loss Generation and Leakage Flow Kinematics in Shrouded Axial Compressor Cascades

2006 ◽  
Author(s):  
D. W. Sohn ◽  
T. Kim ◽  
S. J. Song
Keyword(s):  
Tangential Velocity ◽  
Axial Compressor ◽  
Suction Side ◽  
Velocity Variation ◽  
Leakage Flow ◽  
Compressor Blades ◽  
Blade Passage ◽  
Leakage Flows ◽  
And Behavior ◽  
The Impact

Although compressor blades have long been shrouded for aerodynamic and structural reasons, the impact of the leakage flow in the shroud cavities on passage flows has only recently been investigated. Furthermore, the tangential velocity of the leakage flow, set by the blading and the relative motion between rotating and stationary surfaces, has a strong influence on the passage flow. Yet the influence of the tangential velocity variation on the kinematics and dynamics (loss) of the leakage flow (from its ingress to egress) in the shrouded cavity and main flow in the blade passage are unknown. Therefore, this paper reports on an experimental investigation of the axial evolution of loss generation in the blade passage and behavior of the leakage flow in the seal cavity in shrouded axial compressor cascades subject to the variation of leakage tangential velocity. The newly found results are as follows. First, increasing tangential velocity of the leakage flow reduces loss at 10% and 50% chordwise locations in the passage. However, most of the blockage and loss reductions occurs in the aft half chord and downstream of the blade passage. Second, the increasing tangential velocity spreads the loss core, which is originally concentrated in the suction side hub corner, in the pitchwise direction. Thus, the loss core becomes more two-dimensional, and the region’s radial extent is reduced. Third, increasing tangential velocity of the leakage flow makes the near hub passage flow more radially uniform. Consequently, the shear and resultant mixing loss between the passage and leakage flows are reduced near the hub, reducing the overall loss. Finally, the leakage flow is ingested through the downstream cavity and makes an abrupt turn at the seal tooth. Thus, two distinct flow regions — downstream and upstream of the single-tooth seal — are found. Before the leakage flow rejoins the mainstream via the upstream cavity trench, the leakage flow circumferentially migrates in the direction of rotation. The magnitude of the circumferential shift depends strongly on the leakage tangential velocity.

Differences in Impact Performance of Bicycle Helmets During Oblique Impacts

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Megan L. Bland ◽  
Craig McNally ◽  
Steven Rowson
Keyword(s):  
Real World ◽  
Head Injuries ◽  
Linear Acceleration ◽  
Design Parameters ◽  
Radius Of Curvature ◽  
Head Impacts ◽  
Impact Performance ◽  
Bicycle Helmets ◽  
Oblique Impacts ◽  
Accident Conditions

Cycling is a leading cause of sport-related head injuries in the U.S. Although bicycle helmets must comply with standards limiting head acceleration in severe impacts, helmets are not evaluated under more common, concussive-level impacts, and limited data are available indicating which helmets offer superior protection. Further, standards evaluate normal impacts, while real-world cyclist head impacts are oblique—involving normal and tangential velocities. The objective of this study was to investigate differences in protective capabilities of ten helmet models under common real-world accident conditions. Oblique impacts were evaluated through drop tests onto an angled anvil at common cyclist head impact velocities and locations. Linear and rotational accelerations were evaluated and related to concussion risk, which was then correlated with design parameters. Significant differences were observed in linear and rotational accelerations between models, producing concussion risks spanning >50% within single impact configurations. Risk differences were more attributable to linear acceleration, as rotational varied less between models. At the temporal location, shell thickness, vent configuration, and radius of curvature were found to influence helmet effective stiffness. This should be optimized to reduce impact kinematics. At the frontal, helmet rim location, liner thickness tapered off for some helmets, likely due to lack of standards testing at this location. This is a frequently impacted location for cyclists, suggesting that the standards testable area should be expanded to include the rim. These results can inform manufacturers, standards bodies, and consumers alike, aiding the development of improved bicycle helmet safety.

scholarly journals Head Impacts During High School Football: A Biomechanical Assessment

2009 ◽  
Vol 44 (4) ◽  
pp. 342-349 ◽  
Author(s):  
Steven P. Broglio ◽  
Jacob J. Sosnoff ◽  
SungHoon Shin ◽  
Xuming He ◽  
Christopher Alcaraz ◽  
...  
Keyword(s):  
High School ◽  
Linear Acceleration ◽  
Rotational Acceleration ◽  
High School Football ◽  
Head Impacts ◽  
Biomechanical Assessment ◽  
Football Team ◽  
Impact Biomechanics ◽  
Session Type ◽  
The Impact

Abstract Little is known about the impact biomechanics sustained by players during interscholastic football.Context: To characterize the location and magnitude of impacts sustained by players during an interscholastic football season.Objective: Observational design.Design: On the field.Setting: High school varsity football team (n  =  35; age  =  16.85 ± 0.75 years, height  =  183.49 ± 5.31 cm, mass  =  89.42 ± 12.88 kg).Patients or Other Participants: Biomechanical variables (linear acceleration, rotational acceleration, jerk, force, impulse, and impact duration) related to head impacts were categorized by session type, player position, and helmet impact location.Main Outcome Measure(s): Differences in grouping variables were found for each impact descriptor. Impacts occurred more frequently and with greater intensity during games. Linear acceleration was greatest in defensive linemen and offensive skill players and when the impact occurred at the top of the helmet. The largest rotational acceleration occurred in defensive linemen and with impacts to the front of the helmet. Impacts with the highest-magnitude jerk, force, and impulse and shortest duration occurred in the offensive skill, defensive line, offensive line, and defensive skill players, respectively. Top-of-the-helmet impacts yielded the greatest magnitude for the same variables.Results: We are the first to provide a biomechanical characterization of head impacts in an interscholastic football team across a season of play. The intensity of game play manifested with more frequent and intense impacts. The highest-magnitude variables were distributed across all player groups, but impacts to the top of the helmet yielded the highest values. These high school football athletes appeared to sustain greater accelerations after impact than their older counterparts did. How this finding relates to concussion occurrence has yet to be elucidated.Conclusions:

1607-P: Real-World Evidence of the Impact of Obesity on Residual Teeth in the Japanese Population

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 1607-P
Author(s):  
MAYU HAYASHI ◽  
KATSUTARO MORINO ◽  
KAYO HARADA ◽  
MIKI ISHIKAWA ◽  
ITSUKO MIYAZAWA ◽  
...  
Keyword(s):  
Real World ◽  
Japanese Population ◽  
Real World Evidence ◽  
The Impact

scholarly journals POS1121 DEMOGRAPHICS, COMORBIDITIES, AND RENAL FUNCTION OF UNCONTROLLED GOUT PATIENTS WHO RECEIVED PEGLOTICASE: FINDING FROM A LARGE US CLAIMS DATABASE

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 839.2-840
Author(s):  
C. Vesel ◽  
A. Morton ◽  
M. Francis-Sedlak ◽  
B. Lamoreaux
Keyword(s):  
Kidney Function ◽  
Real World ◽  
Randomized Clinical Trials ◽  
Small Subset ◽  
Phase 3 ◽  
Claims Database ◽  
Medical Diagnoses ◽  
Ckd Stage ◽  
Before And After ◽  
The Impact

Background:NHANES data indicate that approximately 9.2 million Americans have gout,1 with a small subset having uncontrolled disease.2 Pegloticase is a PEGylated recombinant uricase enzyme indicated for treating uncontrolled gout that markedly reduces serum uric acid levels (sUA)3 and resolves tophi in treatment responders.4 Despite pegloticase availability in the US for many years, real world demographics of pegloticase users in the treatment of uncontrolled gout have not been previously reported in a population-based cohort.Objectives:This study utilized a large US claims database to examine demographics and co-morbidities of uncontrolled gout patients treated with pegloticase. Kidney function before and after pegloticase treatment and concomitant therapy with immunomodulators were also examined.Methods:The TriNetX Diamond database includes de-identified data from 4.3 million US patients with gout (as of September 2019), including demographics, medical diagnoses, laboratory values, procedures (e.g. infusions, surgeries), and pharmacy data. Patients who had received ≥1 pegloticase infusion were included in these analyses. The number of infusions was evaluated for a subgroup of patients who were in the database ≥3 months before and ≥2 years after the first pegloticase infusion (i.e. first infusion prior to September 2017) to ensure only complete courses of therapy were captured. In this subpopulation, kidney function before and after pegloticase therapy was examined, along with the presence of immunomodulation prescriptions (methotrexate, mycophenolate mofetil, azathioprine, leflunomide) within 60 days prior to and 14 days after the first pegloticase infusion.Results:1494 patients treated with pegloticase were identified. Patients were 63.1 ± 14.0 years of age (range: 23–91), mostly male (82%), and white (76%). Mean sUA prior to pegloticase was 8.7 ± 2.4 mg/dL (n=50), indicating uncontrolled gout in the identified population. The most commonly reported comorbidities were chronic kidney disease (CKD, 48%), essential hypertension (71%), type 2 diabetes (39%), and cardiovascular disease (38%), similar to pegloticase pivotal Phase 3 trial populations. In patients with pre-therapy kidney function measures (n=134), pre-treatment eGFR averaged 61.2 ± 25.7 ml/min/1.73 m2, with 44% having Stage 3-5 CKD. In patients with complete therapy course capture and pre- and post-therapy eGFR measures (n=48), kidney function remained stable (change in eGFR: -2.9 ± 18.2 ml/min/1.73 m2) and CKD stage remained the same or improved in 81% of patients. In 791 patients with complete treatment course capture, patients had received 8.7 ± 13.8 infusions (median: 3, IQR: 2-10). Of these, 189 (24%) patients received only 1 pegloticase infusion and 173 (22%) received ≥12 infusions. As the data cut-off for this analysis pre-dated emerging data on the use of immunomodulation as co-therapy, only 19 of 791 (2%) patients received immunomodulation co-therapy with pegloticase.Conclusion:This relatively large group of patients with uncontrolled gout treated with pegloticase had similar patient characteristics of those studied in the phase 3 randomized clinical trials. Patients with uncontrolled gout are significantly burdened with systemic co-morbid diseases. The majority of patients had stable or improved kidney function following pegloticase treatment. As these results reflect patients initiating treatment prior to 2018, before co-treatment with immunomodulation was introduced, this cohort only included a small percentage of patients who were co-treated with an immunomodulator. Future studies using more current datasets are needed to evaluate real world outcomes in patients treated with pegloticase/immunomodulator co-therapy and to evaluate the impact of systemic co-morbid diseases.References:[1]Chen-Xu M, et al. Arthritis Rheumatol 2019 71:991-999.[2]Fels E, Sundy JS. Curr Opin Rheumatol 2008;20:198-202.[3]Sundy J, et al. JAMA 2011;306:711-720.[4]Mandell BF, et al. Arthritis Res Ther 2018;20:286.Disclosure of Interests:Claudia Vesel Shareholder of: Horizon Therapeutics plc, Employee of: Horizon Therapeutics plc, Allan Morton Speakers bureau: Sanofi, Amgen, and Horizon, Megan Francis-Sedlak Shareholder of: Horizon Therapeutics plc, Employee of: Horizon Therapeutics plc, Brian LaMoreaux Shareholder of: Horizon Therapeutics plc, Employee of: Horizon Therapeutics plc.

PP469 From Theory To Practice: Which Value Framework Is Applied For Onco-Hematology Therapies In Italy? A 5-year Retrospective Analysis

2020 ◽  
Vol 36 (S1) ◽  
pp. 37-37
Author(s):  
Americo Cicchetti ◽  
Rossella Di Bidino ◽  
Entela Xoxi ◽  
Irene Luccarini ◽  
Alessia Brigido
Keyword(s):  
Real World ◽  
Ad Hoc ◽  
Grey Literature ◽  
National Level ◽  
Pharmaceutical Products ◽  
European Medicines Agency ◽  
The Real ◽  
R Process ◽  
The One ◽  
The Impact

IntroductionDifferent value frameworks (VFs) have been proposed in order to translate available evidence on risk-benefit profiles of new treatments into Pricing & Reimbursement (P&R) decisions. However limited evidence is available on the impact of their implementation. It's relevant to distinguish among VFs proposed by scientific societies and providers, which usually are applicable to all treatments, and VFs elaborated by regulatory agencies and health technology assessment (HTA), which focused on specific therapeutic areas. Such heterogeneity in VFs has significant implications in terms of value dimension considered and criteria adopted to define or support a price decision.MethodsA literature research was conducted to identify already proposed or adopted VF for onco-hematology treatments. Both scientific and grey literature were investigated. Then, an ad hoc data collection was conducted for multiple myeloma; breast, prostate and urothelial cancer; and Non Small Cell Lung Cancer (NSCLC) therapies. Pharmaceutical products authorized by European Medicines Agency from January 2014 till December 2019 were identified. Primary sources of data were European Public Assessment Reports and P&R decision taken by the Italian Medicines Agency (AIFA) till September 2019.ResultsThe analysis allowed to define a taxonomy to distinguish categories of VF relevant to onco-hematological treatments. We identified the “real-world” VF that emerged given past P&R decisions taken at the Italian level. Data was collected both for clinical and economical outcomes/indicators, as well as decisions taken on innovativeness of therapies. Relevant differences emerge between the real world value framework and the one that should be applied given the normative framework of the Italian Health System.ConclusionsThe value framework that emerged from the analysis addressed issues of specific aspects of onco-hematological treatments which emerged during an ad hoc analysis conducted on treatment authorized in the last 5 years. The perspective adopted to elaborate the VF was the one of an HTA agency responsible for P&R decisions at a national level. Furthermore, comparing a real-world value framework with the one based on the general criteria defined by the national legislation, our analysis allowed identification of the most critical point of the current national P&R process in terms ofsustainability of current and future therapies as advance therapies and agnostic-tumor therapies.

scholarly journals Is the use of two versus one long-acting bronchodilator by patients with COPD associated with a higher risk of acute coronary syndrome in real-world clinical practice?

2021 ◽  
Vol 8 (1) ◽  
pp. e000840
Author(s):  
Lianne Parkin ◽  
Sheila Williams ◽  
David Barson ◽  
Katrina Sharples ◽  
Simon Horsburgh ◽  
...  
Keyword(s):  
Acute Coronary Syndrome ◽  
Clinical Practice ◽  
Real World ◽  
Chronic Obstructive ◽  
Treatment Intensification ◽  
Cardiovascular Comorbidity ◽  
Coronary Syndrome ◽  
Long Acting ◽  
The Impact

BackgroundCardiovascular comorbidity is common among patients with chronic obstructive pulmonary disease (COPD) and there is concern that long-acting bronchodilators (long-acting muscarinic antagonists (LAMAs) and long-acting beta2 agonists (LABAs)) may further increase the risk of acute coronary events. Information about the impact of treatment intensification on acute coronary syndrome (ACS) risk in real-world settings is limited. We undertook a nationwide nested case–control study to estimate the risk of ACS in users of both a LAMA and a LABA relative to users of a LAMA.MethodsWe used routinely collected national health and pharmaceutical dispensing data to establish a cohort of patients aged >45 years who initiated long-acting bronchodilator therapy for COPD between 1 February 2006 and 30 December 2013. Fatal and non-fatal ACS events during follow-up were identified using hospital discharge and mortality records. For each case we used risk set sampling to randomly select up to 10 controls, matched by date of birth, sex, date of cohort entry (first LAMA and/or LABA dispensing), and COPD severity.ResultsFrom the cohort (n=83 417), we identified 5399 ACS cases during 281 292 person-years of follow-up. Compared with current use of LAMA therapy, current use of LAMA and LABA dual therapy was associated with a higher risk of ACS (OR 1.28 (95% CI 1.13 to 1.44)). The OR in an analysis restricted to fatal cases was 1.46 (95% CI 1.12 to 1.91).ConclusionIn real-world clinical practice, use of two versus one long-acting bronchodilator by people with COPD is associated with a higher risk of ACS.

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