AI Article Synopsis
Article Abstract
Background: Fast jet aircrew are heavily reliant on anti-G trousers (AGT) and failure of the garment or its pressure supply would expose them to high levels of +Gz acceleration without protection. A previous study demonstrated the severity of this event at high +Gz, but no data exists as to the maximum +Gz level which could be tolerated.
Methods: : While relaxed and with lower body muscle tensing, 10 experienced centrifuge subjects had their AGT deflated after 5 and 30 s of +Gz exposure. Discrete +Gz exposures of increasing intensity were performed until deflation resulted in central light loss (CLL). Visual symptoms, eye-level systolic BP (SBPeye), and mean blood flow velocity in the middle cerebral artery (MCAVmean) were recorded.
Results: The mean +Gz level at CLL following AGT deflation was comparable to that without AGT inflation (+4.07 Gz) and increased by muscle tensing (+0.53 G) independent of exposure duration. Initial visual symptoms occurred more rapidly in the shorter +Gz exposures, while progression to CLL was quicker with muscle tensing compared with relaxed, but never less than 6.7 s. At CLL, the nadir in SBPeye was higher (+17 mmHg) with muscle tensing compared with relaxed, while MCAVmean was decreased by about 50% in all conditions.
Discussion: +Gz tolerance following AGT deflation is comparable to that without inflation and only modestly increased by muscle tensing. Although vision is maintained for several seconds following AGT deflation, progression of light loss symptoms can be rapid, possibly resulting in insufficient time to respond before G-induced loss of conciousness (G-LOC) ensues.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.3357/asem.3773.2014 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Scapular swelling: "subcutaneous cysticercosis unveiled"-a case report.
J Med Case Rep
December 2024
Department of General Medicine, INHS Asvini, Mumbai, India.
Background: Cysticercosis, a parasitic infection caused by the larval stages of the pork tapeworm, Taenia solium, predominantly affects cerebral and ocular tissues. The subcutaneous manifestation of this disease is a relatively uncommon clinical occurrence. Previously very few or no cases of cysticercosis presenting as subcutaneous solitary painful swelling have been reported in the literature.
View Article and Find Full Text PDFIntroduction: During centrifuge-simulated suborbital spaceplane flights, launch and re-entry frequently cause visual symptoms, and G-induced loss of consciousness can occur. G-related effects may be more prominent during re-entry from microgravity on actual flights. A modified anti-G maneuver that does not involve a breath strain and is suitable for members of the public may be effective against these effects.
View Article and Find Full Text PDFOn the consequences of intra-operative release versus over-tensioning of the posterior cruciate ligament in total knee arthroplasty.
J R Soc Interface
December 2024
Aesculap AG, Research & Development, Tuttlingen, Germany.
Intra-operative tensioning of the posterior cruciate ligament (PCL) in total knee arthroplasty (TKA) is commonly based on the surgeon's experience, resulting in a possibly loose or overly tight PCL. To date, the consequences of different PCL tensioning scenarios for the post-operative biomechanics of the knee remain unclear. Using a comprehensive musculoskeletal modelling approach that allows predictive joint kinematic and kinetic balance, we assessed variations in the movement and loading patterns of the knee as well as changes in ligament and muscle forces during walking in response to systematic variations in the PCL reference strain.
View Article and Find Full Text PDFImmediate effects of Kinesio taping on pain, proprioception, and posture in round shoulder individuals with subacromial impingement syndrome: A randomized, double-blinded controlled trial.
Medicine (Baltimore)
December 2024
Department of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Bahçeşehir University, Istanbul, Turkiye.
Background: Round shoulder posture (RSP), characterized by forward shoulder positioning from weakened and tense muscles, disrupts normal biomechanics and can cause Subacromial impingement syndrome (SIS), resulting in pain during specific movements or positions. This study examines the immediate effects of Kinesio taping (KT) on pain, proprioception, and posture in individuals in round shoulder individuals with SIS.
Methods: The study involved 114 patients diagnosed with RSP and SIS.
The Association Between Specific Oral Behaviors and the Number of Temporomandibular Disorder Symptoms in the General Population: A Cross-Sectional Study.
J Pain Res
November 2024
State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Chengdu, Sichuan, People's Republic of China.
Objective: This study aimed to thoroughly explore the relationship between individual oral behavior and the differing numbers of temporomandibular disorder (TMD) symptom in the general population.
Methods: A total of 565 participants were recruited and completed a questionnaire containing demographic characteristics, eight specific oral behaviors, and five major TMD symptoms (5Ts) checklist. Multivariate linear regression analysis was performed to assess the relationship between individual oral behavior and the number of TMD symptoms, after controlling for confounders.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!