High G-forces Research Articles

Association Between Cumulative G-force Exposure and Cervical Spine Degenerative Changes.

Fighter pilots work in a unique environment and are subject to high G-force loads under simultaneous head movements. Neck pain is reported to be a common health problem among fighter pilots leading to time lost flying and flight duty limitations. The present study aimed to find out if differences in early military flight career G-force exposure levels could increase the risk for degenerative changes in the cervical spine. The study population consisted of 56 20-year-old Finnish Air Force male fighter pilot cadets, who underwent MRI of the cervical spine at baseline and after 5 years. During follow-up, the G-force exposure was measured using the individual Fatigue Index (FI) recordings. The FI data were collected from each flight with BAE Hawks and is determined by the number of times certain levels of G-forces are exceeded during the flights. The incidence or progression of each degenerative change was compared to individual FI values using Pearson correlation coefficients. The pilots flew on average 220 (±21) hours with high performance aircraft during follow-up, resulting in an average FI of 1.98 (±0.47). A statistically significant progression was found in intervertebral disc (IVD) degeneration sum score with no correlation to corresponding FI values. A statistically significant increase was also found in the prevalence of IVD herniations with a negative correlation with FI values. Other degenerative cervical spine changes did not progress or did not correlate with corresponding FI values. The prevalence of IVD degeneration and IVD herniations increases in the early phases of fighter pilots' career. Only the incidence of IVD herniations correlated with FI values and the correlation was negative. The negative correlation may be attributed to avoidance behavior due to neck pain, which was not measured in our study, or other unmeasured confounding factors. This was the first study to compare individual G-force exposure levels to high-quality MRI data over a follow-up of several years. Finnish fighter pilots are known to report increasing cervical symptoms during the Hawk training phase, but longer follow-up periods are likely needed to determine the association between G-force exposure levels and cervical degenerative changes.

Analysis of the relationship between body imbalance characteristics and physical ability in air force cadets: physical function and gravity acceleration resistance

Air Force pilots and some athletes (e.g., in sledding sports) are frequently exposed to high G-forces. High-intensity physical activity is essential to withstand gravitational acceleration, and morphological symmetry and functional movement are directly related to injury in those who perform these activities. However, the relationship between G-endurance and physical imbalance and the effect on physical performance is poorly understood. This study aimed to analyze the physical performance of those exposed to a high load of G-tolerance and who performed high-intensity physical activity. A total of 363 male cadets from the Korean Air Force Academy underwent functional movement screen tests, anatomical structure measurements, G-tests (fourth grade), and body composition and physical fitness tests. Participants were classified into the G-test-pass and -fail groups depending on the G-test results. The pass group showed significantly different bilateral imbalance in active straight leg raises (p < 0.05), while the fail group showed a significant difference in deep squats (p < 0.05), shoulder mobility (p < 0.01), rotary stability (p < 0.05), and functional leg length (p < 0.05). Leg length was significantly correlated with the hurdle step (p < 0.01), inline lunge (p < 0.01), and active straight leg raise (p < 0.01). Functional leg lengths on both sides and structural leg lengths were also significantly correlated (p < 0.01). High body balance positively affects gravitational acceleration and exercise performance. Therefore, functional movement and physical imbalance affect performance in pilots affected by gravitational acceleration. This study can also be applied to strengthen the performance of winter sports athletes affected by gravitational acceleration.

Effects of high-gravity acceleration forces and anti-gravity maneuver on the cardiac function of fighter pilots.

The fighter pilots exposed to high gravitational (G) acceleration must perform anti-G maneuvers similar to the Valsalva maneuver. However, the effects of high-G acceleration and anti-G maneuvers on cardiac function have rarely been studied. This study aimed to investigate the effects of high-G forces on cardiac function of fighter pilots. Fighter pilots who underwent regular health check-ups and echocardiography were included (n = 29; 100% men, 41 ± 10years old; mean flight time, 1821 ± 1186h). Trainees who had not experienced any flights were included in the control group (n = 16; 100% men, 36 ± 17years old). Echocardiographic data included left ventricular chamber size, systolic and diastolic functions, right ventricular systolic pressure (RVSP), inferior vena cava (IVC) collapsibility, and tricuspid annular plane systolic excursion (TAPSE). No significant differences in left ventricular ejection fraction, RVSP, or IVC collapsibility were observed between two groups. In the multivariate linear regression analysis with total flight time as an independent continuous variable for fighter pilots, TAPSE was positively correlated with total flight time. The experience of fighter pilots who were exposed to high-G acceleration forces and anti-G maneuvers did not cause cardiac structural changes, but the exposure might be associated with right heart function changes.

Material Optimization in Formula One Seat Fit Based on Structural and Biomechanical Analysis

F1 drivers have reported that they suffer a long-term lower back pain due to ‘Porpoising’ effect, it is a series of bounce that is generated due to Aerodynamic downforce. This downforce is part of drag reduction principle that pulls the air underneath the vehicle, thereby creating an incredible speed of 200 to 230 mph. Also at 200 mph speed, the driver experiences a high amount G-forces up to six times during the race. This can be simply avoided by increasing the ground clearance of vehicle but at the same time it also reduces the max speed of the vehicle. Hence, without compromising the speed, Design optimization is done for driver’s seat-fit through Computational methods of Biomechanical modelling and simulation for determining the optimum Seat Angle for Postural Ergonomics. As an additional Reinforcement and Shock absorption in seat material to protect driver’s spine from the resulting dynamics, Material optimization is done by selecting Graphene as the suitable material over the existing Carbon fiber material. Finite element method was carried out for structural analysis of seat-fit model. The stress, strain and deformation values were found to be lesser in Graphene model when compared to Carbon fiber. The simulation results will provide a solution for eliminating the higher risk of spine injury or pathological condition of a sportsman and thereby improves the sporting performance. Key Word: Motorsports, Computational Biomechanics, Ergonomics, Design optimization, Material optimization, Finite element analysis, Spine Injury prevention

Cerebral oxygenation and perfusion kinetics monitoring of military aircrew at high G using novel fNIRS wearable system.

Real-time physiological episode (PE) detection and management in aircrew operating high-performance aircraft (HPA) is crucial for the US Military. This paper addresses the unique challenges posed by high acceleration (G-force) in HPA aircrew and explores the potential of a novel wearable functional near-infrared spectroscopy (fNIRS) system, named NIRSense Aerie, to continuously monitor cerebral oxygenation during high G-force exposure. The NIRSense Aerie system is a flight-optimized, wearable fNIRS device designed to monitor tissue oxygenation 13-20 mm below the skin's surface. The system includes an optical frontend adhered to the forehead, an electronics module behind the earcup of aircrew helmets, and a custom adhesive for secure attachment. The fNIRS optical layout incorporates near-distance, middle-distance, and far-distance infrared emitters, a photodetector, and an accelerometer for motion measurements. Data processing involves the modified Beer-Lambert law for computing relative chromophore concentration changes. A human evaluation of the NIRSense Aerie was conducted on six subjects exposed to G-forces up to +9 Gz in an Aerospace Environmental Protection Laboratory centrifuge. fNIRS data, pulse oximetry, and electrocardiography (HR) were collected to analyze cerebral and superficial tissue oxygenation kinetics during G-loading and recovery. The NIRSense Aerie successfully captured cerebral deoxygenation responses during high G-force exposure, demonstrating its potential for continuous monitoring in challenging operational environments. Pulse oximetry was compromised during G-loading, emphasizing the system's advantage in uninterrupted cerebrovascular monitoring. Significant changes in oxygenation metrics were observed across G-loading levels, with distinct responses in Deoxy-Hb and Oxy-Hb concentrations. HR increased during G-loading, reflecting physiological stress and the anti-G straining maneuver. The NIRSense Aerie shows promise for real-time monitoring of aircrew physiological responses during high G-force exposure. Despite challenges, the system provides valuable insights into cerebral oxygenation kinetics. Future developments aim for miniaturization and optimization for enhanced aircrew comfort and wearability. This technology has potential for improving anti-G straining maneuver learning and retention through real-time cerebral oxygenation feedback during centrifuge training.

External Hemorrhage Control Techniques for Human Space Exploration: Lessons from the Battlefield.

The past few decades of military experience have brought major advances in the prehospital care of patients with trauma. A focus on early hemorrhage control with aggressive use of tourniquets and hemostatic gauze is now generally accepted. This narrative literature review aims to discuss external hemorrhage control and the applicability of military concepts in space exploration. In space, environmental hazards, spacesuit removal, and limited crew training could cause significant time delays in providing initial trauma care. Cardiovascular and hematological adaptations to the microgravity environment are likely to reduce the ability to compensate, and resources for advanced resuscitation are limited. Any unscheduled emergency evacuation requires a patient to don a spacesuit, involves exposure to high G-forces upon re-entry into Earth's atmosphere, and costs a significant amount of time until a definitive care facility is reached. As a result, early hemorrhage control in space is critical. Safe implementation of hemostatic dressings and tourniquets seems feasible, but adequate training will be essential, and tourniquets are preferably converted to other methods of hemostasis in case of a prolonged medical evacuation. Other emerging approaches such as early tranexamic acid administration and more advanced techniques have shown promising results as well. For future exploration missions to the Moon and Mars, when evacuation is not possible, we look into what training or assistance tools would be helpful in managing the bleed at the point of injury.

A new and efficient enrichment method for metagenomic sequencing of Monkeypox virus

BackgroundThe methodology described in previous literature for Monkeypox virus (MPXV) sequencing shows low efficiency when using metagenomic approaches. The aim of the present study was to evaluate a new fine-tuned method for extraction and enrichment of genomic MPXV DNA using clinical samples and to compare it to a non-enrichment metagenomic approach.ResultsA new procedure that allows sample enrichment in MPXV DNA, avoiding wasting the sequencing capacity in human DNA, was designed. This procedure consisted of host DNA depletion using a saponin/NaCl combination treatment and DNase, together with high g-force centrifugations. After typical quality control, samples using the enrichment method contained around 96% of reads not classified as human DNA, while the non-enrichment protocol showed around 5-10%. When reads not belonging to Orthopoxvirus were removed, enriched samples kept about 50% of the original read counts, while non-enriched ones kept only 2-7%.ConclusionsResults showed a very significant improvement in sequencing efficiency, increasing the number of reads belonging to MPXV, the depth of coverage and the trustworthiness of the consensus sequences. This, in turn, allows for more samples to be included in a single cartridge, reducing costs and time to diagnosis, which can be very important factors when dealing with a contagious disease.

Cardiovascular Concerns from COVID-19 in Pilots.

BACKGROUND: Cardiovascular disease, now complicated by the COVID-19 pandemic, remains a leading cause of death and risk for sudden incapacitation for pilots during flight. The capacity for aeromedically significant cardiovascular sequelae with potentially imperceptible clinical symptoms elicits concern both during and following resolution of acute COVID-19 in pilots.OBJECTIVE: We summarize the current state of knowledge regarding COVID-19 cardiovascular implications as applied to the aviation environment to better understand their significance toward flight safety and application toward a focused cardiovascular screening protocol following recovery from infection.METHODS: A narrative review of the cardiovascular implications of COVID-19 infection was performed using the PubMed literature search engine and existing organizational guidelines. In addition, to established medical aviation benchmarks, surrogate populations examined included high performance athletes (as a correlate for high G-forces), and scuba divers (as an environmental work analog). Conditions of primary concern included myocardial injury, proarrhythmic substrates, risk of sudden death, myopericarditis, pulse orthostatic lability in response to vigorous activity, cardiovagal dysfunction, and thromboembolic disease.LITERATURE REVIEW: Cardiovascular screening guideline recommendations post-infection recovery are suggested based on profile stratification: airperson flight class, tactical military, and aerobatic pilots. This provides an approach to inform aeromedical decision making.CONCLUSION: Aviation medical examiners should remain cognizant of the clinically apparent and occult manifestations of cardiovascular dysfunction associated with COVID-19 infection when applying return-to-work screening guidelines. This will ensure high flight safety standards are maintained and sudden incapacitation risk mitigated during and following the ongoing pandemic.Elkhatib W, Herrigel D, Harrison M, Flipse T, Speicher L. Cardiovascular concerns from COVID-19 in pilots. Aerosp Med Hum Perform. 2022; 93(12):855-865.

Predictors of risky driving among teen drivers with ADHD during U.S. COVID-19 shelter in place orders

Factors associated with continued driving during shelter in place orders have been examined in a community sample of typically developing teen drivers, but not in teens diagnosed with Attention/Deficit-Hyperactivity Disorder (ADHD). Our objective was to examine psychosocial factors that predicted risky drivingduring shelter in place orders in teens with ADHD, which is important since teens with ADHD are at particular risk for poor driving outcomes. The present study is also novel in that it uses naturalistic data of risky driving rather than self-report of continued driving. Naturalistic in-car data from 56 ADHD participants (M age = 16.875 years,SD = 0.955; 55.400 % were male) enrolled in an on-going study were used in the present study. Teens had an average of 26.915 months (SD = 14.343) of driving experience. Risky driving was defined as experiencing an event exceeding 0.600 g-force during the first month of COVID-19 pandemic shelter in place ordinances in Ohio, Kentucky, and Indiana, USA. A hierarchical logistic regression with a post-COVID driving event as the dependent variable was conducted. Baseline ratings of ADHD and oppositional defiant disorder/conduct disorder (ODD/CD) severity were entered in the first step of the model, while anxiety severity and parent behaviors regarding teen driving safety (monitoring and limit setting) were entered in the second step of the model. The first step of the model reached statistical significance (χ2(2, 54) = 7.577, p =.023), with only greater symptoms of ODD/CD significantly predicting a post-COVID driving event (B = 0.144, p =.020). With each point increase in ODD/CD symptoms, there was a 15.5 % increase in the probability of experiencing a high g-force event during COVID-19 restrictions. The model was no longer significant at step 2 when anxiety severity and parent behaviors were added to the model (χ2(3, 55) = 10.97p =.052).We conclude that ODD/CD symptom severity was the strongest predictor of risky driving during COVID-19 restrictions within a sample of teen drivers with ADHD. Study implications may be beneficial for clinicians who work with families of teenswith ADHD; suggestions for strategies mitigating this risk are discussed. These findings also have implications for which teens with ADHD may be less positively impacted by other government mitigation strategies such as Graduated Drivers Licensing (GDL) regulations.

Pain in the Cervical and Lumbar Spine as a Result of High G-Force Values in Military Pilots-A Systematic Review and Meta-Analysis.

Neck pain and lower back pain are commonly reported by military pilots. That is why the answers to the following questions are important: (1) which part of the back (neck or lumbar spine) is more likely to be painful in military pilots as a result of high G-force, and (2) what intervention methods do pilots use as countermeasures for back pain resulting from high G-force? To answer these questions, the literature was searched in the following online databases: MEDLINE, PubMed, and Embase. A meta-analysis of eleven studies on pain in the neck–spine in fighter pilots vs. transport pilots showed pooled pulled OR = 1.69 (95% CI 1.25 to 2.29, I2 = 32%, p-value = 0.21); this outcome is consistent with most of the published results. A meta-analysis of five studies on pain in the lumbar spine (lower back) did not show a difference between fighter pilots vs. transport pilots with OR = 1 (95% CI 0.83 to 1.19, I2 = 0%, p-value = 0.96). The meta-analysis showed that of the two spinal segments evaluated, it was the cervical spine that showed more soreness in tactical fighter pilots. Prevention of lumbar and neck injuries should be combined with individual lumbar and neck support, as well as increasing back muscle strength through training.

A Resolved Simulation Approach to Investigate the Separation Behavior in Solid Bowl Centrifuges Using Material Functions

The separation of finely dispersed particles from liquids is a basic operation in mechanical process engineering. On an industrial scale, continuously operating decanter centrifuges are often used, whose separation principle is based on the density difference between the solid and the liquid phase due to high g-forces acting on both phases. The design of centrifuges is based on the experience on the individual manufacturer or simplified black box models, which only consider a stationary state. Neither the physical behavior of the separation process nor the sediment formation and its transport is considered. In this work, a computationally-efficient approach is proposed to simulate the separation process in decanter centrifuges. Thereby, the open-source computation software OpenFOAM was used to simulate the multiphase flow within the centrifuge. Sedimentation, consolidation of the sediment, and its transport are described by material functions which are derived from experiments. The interactions between the particles and the fluid are considered by locally defined viscosity functions. This work shows that the simulation method is suitable for describing the solid-liquid separation in a simplified test geometry of a decanter centrifuge. In addition, the influence of the rheological behavior on the flow in the test geometry can be observed for the first time.

Enrichment of bovine milk-derived extracellular vesicles using surface-functionalized cellulose nanofibers

The isolation of extracellular vesicles (EVs) from milk, a complex mixture of colloidal structures having a comparable size to EVs, is challenging. Although ultracentrifugation (UC) has been widely used for EV isolation, this has significant limitations, including a long processing time at high g-force conditions and large sample volume requirements. We introduced a new approach based on nature nanoentities cellulose nanofibers (CNFs) and short time and low g-force centrifugation to isolate EVs from various milk fractions. The flexible and entangled network of CNFs forms nanoporous, which entraps the EVs. Further, positively charged CNFs interact with anionic EVs through an electrostatic attraction, promoting their isolation with efficiency comparable with UC. The functionality and toxicity of isolated milk EVs were tested in Caco2 cells. Overall, the newly developed approach provides straightforward isolation and biocompatibility and preserves the natural properties of the isolated EVs, enabling further applications.

Microvalve array fabrication using selective PDMS (polydimethylsiloxane) bonding through Perfluorooctyl-trichlorosilane passivation for long-term space exploration

To improve the versatility and robustness of microfluidic analytical devices for space exploration, a programmable microfluidic array (PMA) has been implemented to support a variety of missions. When designing a PMA, normally closed valves are advantageous to avoid cross contamination and leaking. However, a stable fabrication method is required to prevent these valves from sticking and bonding over time. This work presents how polydimethylsiloxane (PDMS) can be bonded selectively using chemical passivation to overcome PDMS sticking issue during long-term space exploration. First, on a PDMS stamp, the vaporized perfluorooctyl-trichlorosilane (PFTCS) are deposited under − 80 kPa and 150 °C conditions. The PFTCS was then transferred onto PDMS or glass substrates by controlling temperature and time and 15 min at 150 °C provides the optimal PFTCS transfer for selective bonding. With these characterized parameters, we successfully demonstrated the fabrication of PMA to support long-term space missions. To estimate the stability of the stamped PFTCS, a PMA has been tested regularly for three years and no stiction or performance alteration was observed. A flight test has been done with a Cessaroni L1395 rocket for high g-force and vibration test and there is no difference on PMA performance after exposure of launch and landing conditions. This work shows promise as a simple and robust technique that will expand the stability and capability of PMA for space exploration.

A LONG-TERM 10G-HYPERGRAVITY EXPOSURE PROMOTES CELL-CELL CONTACTS AND REDUCES ADHESIVENESS TO A SUBSTRATE, MIGRATION, AND INVASIVENESS OF MCF-7HUMAN BREAST CANCER CELLS.

G-force is a fundamental force controlling human cells. Cancer is one of the 4major health challenges in the Space missions. Cancer in Space project evaluates the reaction of human cancer cells to the conditions of the space flights, including an exposure to high g-forces. Explore an impact of 10g force on the oncogenic properties of human breast adenocarcinoma cells MCF-7. Cells were exposed to 10g force for 10days, as part of a 6-week simulation of conditions of a space flight. Then the cells were cultured for one week under normal culture conditions, before performing tests. Cell proliferation, cell viability, cell-cell contact inhibition, migration, and invasiveness were measured. Immunoblotting was used to evaluate expression of proteins. Proliferation, cell-cell interaction and formation of 3D structures, migration, and invasiveness of cells exposed to 10g were compared to parental cells cultured at 1g condition. 10g exposed cells showed a higher propensity for cell-cell contact inhibitions and lower for 3-dimensional growth in dense culture. This correlated with the decrease of proliferation in a dense culture as compared to the parental cells. The decrease of migration, adherence to a surface, and invasiveness was observed for cells subjected to the hypergravity, as compared to the parental MCF-7cells. Enhanced expression of E-cadherin and phosphorylated pY576-FAK were observed in 10g exposed cells but no impact on the expression of Erk, pErk, FAK and p53was detected. The prolonged exposure of MCF-7cells to 10g force targets cell-cell and cell-substrate interactions.

A Measurement of ‘Walking-the-Wall’ Dynamics: An Observational Study Using Accelerometry and Sensors to Quantify Risk Associated with Vertical Wall Impact Attenuation in Trampoline Parks

This study illustrates the application of a tri-axial accelerometer and gyroscope sensor device on a trampolinist performing the walking-the-wall manoeuvre on a high-performance trampoline to determine the performer dynamic conditions. This research found that rigid vertical walls would allow the trampolinist to obtain greater control and retain spatial awareness at greater levels than what is achievable on non-rigid vertical walls. With a non-rigid padded wall, the reaction force from the wall can be considered a variable force that is not constrained, and would not always provide the feedback that the trampolinist needs to maintain the balance with each climb up the wall and fall from height. This research postulates that unattenuated vertical walls are safer than attenuated vertical walls for walking-the-wall manoeuvres within trampoline park facilities. This is because non-rigid walls would provide higher g-force reaction feedback from the wall, which would reduce the trampolinist’s control and stability. This was verified by measuring g-force on a horizontal rigid surface versus a non-rigid surface, where the g-force feedback was 27% higher for the non-rigid surface. Control and stability are both critical while performing the complex walking-the-wall manoeuvre. The trampolinist experienced a very high peak g-force, with a maximum g-force of approximately 11.5 g at the bottom of the jump cycle. It was concluded that applying impact attenuation padding to vertical walls used for walking-the-wall and similar activities would increase the likelihood of injury; therefore, padding of these vertical surfaces is not recommended.

Photoplethysmography behind the Ear Outperforms Electrocardiogram for Cardiovascular Monitoring in Dynamic Environments.

An increasing proportion of occupational mishaps in dynamic, high-risk operational environments have been attributed to human error, yet there are currently no devices to routinely provide accurate physiological data for insights into underlying contributing factors. This is most commonly due to limitations of commercial and clinical devices for collecting physiological data in environments of high motion. Herein, a novel Photoplethysmography (PPG) sensor device was tested, called SPYDR (Standalone Performance Yielding Deliberate Risk), reading from a behind-the-ear location, specifically designed for high-fidelity data collection in highly dynamic high-motion, high-pressure, low-oxygen, and high-G-force environments. For this study, SPYDR was installed as a functional ear-cup replacement in flight helmets worn by rated US Navy aircrew. Subjects were exposed to reduced atmospheric pressure using a hypobaric chamber to simulated altitudes of 25,000 feet and high G-forces in a human-rated centrifuge up to 9 G acceleration. Data were compared to control devices, finger and forehead PPG sensors, and a chest-mounted 12-lead ECG. SPYDR produced high-fidelity data compared to controls with little motion-artifact controls in the no-motion environment of the hypobaric chamber. However, in the high-motion, high-force environment of the centrifuge, SPYDR recorded consistent, accurate data, whereas PPG controls and ECG data were unusable due to a high-degree-motion artifacts. The data demonstrate that SPYDR provides an accurate and reliable system for continuous physiological monitoring in high-motion, high-risk environments, yielding a novel method for collecting low-artifact cardiovascular assessment data important for investigating currently inaccessible parameters of human physiology.

Hypergravity affects cell traction forces of fibroblasts

Cells sense and react on changes of the mechanical properties of their environment and, likewise, respond to external mechanical stress applied to them. However, whether the gravitational field as overall body force modulates cellular behavior is unclear. Different studies demonstrated that micro- and hypergravity influences the shape and elasticity of cells, initiate cytoskeleton reorganization, and influence cell motility. All these cellular properties are interconnected and contribute to forces that cells apply on their surrounding microenvironment. Yet, studies that investigated changes of cell traction forces under hypergravity conditions are scarce. Here, we performed hypergravity experiments on 3T3 fibroblast cells using the large-diameter centrifuge at the European Space Agency - European Space Research and Technology Centre. Cells were exposed to hypergravity of up to 19.5 g for 16 h in both the upright and the inverted orientation with respect to the g-force vector. We observed a decrease in cellular traction forces when the gravitational field was increased up to 5.4 g, followed by an increase of traction forces for higher gravity fields up to 19.5 g independent of the orientation of the gravity vector. We attribute the switch in cellular response to shear thinning at low g-forces, followed by significant rearrangement and enforcement of the cytoskeleton at high g-forces.

Machine Learning and Accelerated Stress Approaches to Differentiate Potential Causes of Aggregation in Polyclonal Antibody Formulations During Shipping.

Therapeutic proteins are among the most widely prescribed medications, with wide distribution and complex supply chains. Shipping exposes protein formulations to stresses that can trigger aggregation, although the exact mechanism(s) responsible for aggregation are unknown. To better understand how shipping causes aggregation, we compared populations of aggregates that were formed in a polyclonal antibody formulation during live shipping studies to populations observed in accelerated stability studies designed to mimic both the sporadic high g-force and continuous low g-force stresses encountered during shipping. Additionally, we compared the effects on aggregation levels generated in two types of secondary packaging, one of which was designed to mitigate the effects of large g-force stresses. Aggregation was quantified using fluorescence intensity of 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid (bis-ANS) dye, size exclusion high performance liquid chromatography (SECHPLC), and flow imaging microscopy (FIM). FIM was also combined with machine learning methods to analyze particle morphology distributions. These comparisons revealed that the morphology distributions of aggregates formed during live shipping resemble distributions that result from low g-force events, but not those observed following high g-force events, suggesting that low g-force stresses play a predominant role in shipping-induced aggregation.

Modifications of viscoelastic properties and physiological parameters after performing uphill and downhill running trials.

Trail running performance depends on many factors, including energy cost of running, biomechanical parameters and stiffness. The aim of this study was to examine the influence of different positive and negative slopes on metabolic cost, tight hemoglobin saturation, viscoelastic properties, and vertical peak impacts in physically active young runners. Nine healthy male volunteers (26±5 years) performed two separate uphill and downhill sessions on an instrumented treadmill; both sessions were completed in a random order at a constant running speed with variable slopes from 0% to ±20%. Oxygen uptake (V̇O<inf>2</inf>), carbon dioxide production (V̇CO<inf>2</inf>), pulmonary ventilation (V̇E), respiratory exchange ratio, heart rate (HR), muscle oxygen saturation, vertical impacts, and muscle tone and stiffness were assessed. During downhill running, V̇O<inf>2peak</inf> and V̇CO<inf>2</inf> significantly decreased, and impacts higher than 6G significantly increased with a negative slope. During uphill running, V̇O<inf>2peak</inf>, V̇CO<inf>2</inf>, V̇E, and maximum HR significantly increased. Minimum values of oxygen saturation and the vastus medialis tone significantly decreased and impacts of 4-5 G significantly increased with a positive slope. Metabolic demand increased proportionally with the uphill slope and showed a linear negative relationship with a light and moderate downhill slope. Vertical impacts of high G-forces increased during downhill running, data that indicate the importance of our ability to attenuate impacts. Finally, muscle tone and stiffness remained stable at all times, results that demonstrated their acute adaptation to running in the absence of extreme fatigue.

Purification of Recombinant Adeno-Associated Viruses (rAAVs) by Cesium Chloride Gradient Sedimentation.

Centrifugation to equilibrium in cesium chloride gradients has been used for more than 40 yr to purify viruses. The application of high G-forces for a long period of time to a solution of CsCl generates a density gradient that allows separation of empty, partially packaged, and fully packaged viral particles from cellular debris, proteins, and nucleic acids in the crude viral lysate on the basis of their buoyant densities. This protocol describes the use of CsCl gradients to purify AAV vectors from crude viral lysates.