37 research outputs found
Are monodisperse phospholipid-coated microbubbles “mono-acoustic?”
Phospholipid-coated microbubbles with a uniform acoustic response are a promising avenue for functional ultrasound sensing. A uniform acoustic response requires both a monodisperse size distribution and uniform viscoelastic shell properties. Monodisperse microbubbles can be produced in a microfluidic flow focusing device. Here, we investigate whether such monodisperse microbubbles have uniform viscoelastic shell properties and thereby a uniform “mono-acoustic” response. To this end, we visualized phase separation of the DSPC and DPPE-PEG5000 lipid shell components and measured the resonance curves of nearly 2000 single and freely floating microbubbles using a high-frequency acoustic scattering technique. The results demonstrate inhomogeneous phase-separated shell microdomains across the monodisperse bubble population, which may explain the measured inhomogeneous viscoelastic shell properties. The shell viscosity varied over an order of magnitude and the resonance frequency by a factor of two indicating both a variation in shell elasticity and in initial surface tension despite the relatively narrow size distribution.</p
Are monodisperse phospholipid-coated microbubbles “mono-acoustic?”
Phospholipid-coated microbubbles with a uniform acoustic response are a promising avenue for functional ultrasound sensing. A uniform acoustic response requires both a monodisperse size distribution and uniform viscoelastic shell properties. Monodisperse microbubbles can be produced in a microfluidic flow focusing device. Here, we investigate whether such monodisperse microbubbles have uniform viscoelastic shell properties and thereby a uniform “mono-acoustic” response. To this end, we visualized phase separation of the DSPC and DPPE-PEG5000 lipid shell components and measured the resonance curves of nearly 2000 single and freely floating microbubbles using a high-frequency acoustic scattering technique. The results demonstrate inhomogeneous phase-separated shell microdomains across the monodisperse bubble population, which may explain the measured inhomogeneous viscoelastic shell properties. The shell viscosity varied over an order of magnitude and the resonance frequency by a factor of two indicating both a variation in shell elasticity and in initial surface tension despite the relatively narrow size distribution.</p
Are monodisperse phospholipid-coated microbubbles “mono-acoustic?”
Phospholipid-coated microbubbles with a uniform acoustic response are a promising avenue for functional ultrasound sensing. A uniform acoustic response requires both a monodisperse size distribution and uniform viscoelastic shell properties. Monodisperse microbubbles can be produced in a microfluidic flow focusing device. Here, we investigate whether such monodisperse microbubbles have uniform viscoelastic shell properties and thereby a uniform “mono-acoustic” response. To this end, we visualized phase separation of the DSPC and DPPE-PEG5000 lipid shell components and measured the resonance curves of nearly 2000 single and freely floating microbubbles using a high-frequency acoustic scattering technique. The results demonstrate inhomogeneous phase-separated shell microdomains across the monodisperse bubble population, which may explain the measured inhomogeneous viscoelastic shell properties. The shell viscosity varied over an order of magnitude and the resonance frequency by a factor of two indicating both a variation in shell elasticity and in initial surface tension despite the relatively narrow size distribution.</p
Fast-Speed Compared to Slow-Speed Eccentric Muscle Actions are Detrimental to Jump Performance in Elite Soccer Players In-Season
Purpose: To examine the effect of fast-speed vs. slow-speed eccentric muscle actions resistance training on lower-body strength, vertical jump height, sprint speed and COD performance in elite soccer players during a competitive season. Methods: Twenty-two elite soccer players, from a single team, were randomly selected to groups that undertook either 1 s (fast speed [1S]) or 4 s (slow speed [4S]) eccentric resistance training during the in-season period. A five-week programme was conducted during an elite top division European League soccer season. Performance measures, including predicted one repetition maximum (1RM) back squat, countermovement jump (CMJ), 20 m sprint and change of direction (COD) were tested before and after the intervention period. Total match and training running distance and muscle soreness were also recorded during each week of the intervention. Results: An ANCOVA showed significant group effects (P = 0.01) for CMJ with a greater jump height in the 1S group post-intervention (95% CI [1.1 to 6.9 cm]). Despite an overall increase in 1RM pre- to post-training (95% CI [10.0 kg to 15.3 Kg], ES: 0.69), there were no significant differences (P > 0.05) between groups after the intervention. Similarly, there were no differences between groups for COD, 20 m sprint or muscle soreness. Conclusion: Faster eccentric muscle actions may be superior for increasing jumping movements in elite soccer players in-season
Combined optical sizing and acoustical characterization of single freely-floating microbubbles
AI is a viable alternative to high throughput screening: a 318-target study
: High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery