Knee valgus in self-initiated vertical jump landings: developmental and gender comparisons

The study examined gender and developmental differences in knee valgus angle and external knee valgus moment at the time of maximal vertical ground reaction force (MGRFz) in self-initiated vertical jump (VJ) landings. Fifty-six subjects grouped by age (pre-pubescent (8-11 yrs); post-pubescent (19-29 yrs)) and gender jumped for a ball set at 50% of their maximum VJ height then landed on two feet with only their dominant foot on the force plate. Statistical analyses of motion analysis (3-D) and GRF data showed that children had greater valgus angles (p = .003) and moments (p = .026) at MGRFz compared to adults. Females had greater (p = .016) valgus moments than males, but similar valgus angles at MGRFz. It will be important to ensure that as both boys and girls progress through puberty they develop an ability to offset high valgus moments and land with good lower extremity alignment

Knee valgus in self-initiated vertical jump landings: developmental and gender comparisons

The study examined gender and developmental differences in knee valgus angle and external knee valgus moment at the time of maximal vertical ground reaction force (MGRFz) in self-initiated vertical jump (VJ) landings. Fifty-six subjects grouped by age (pre-pubescent (8-11 yrs); post-pubescent (19-29 yrs)) and gender jumped for a ball set at 50% of their maximum VJ height then landed on two feet with only their dominant foot on the force plate. Statistical analyses of motion analysis (3-D) and GRF data showed that children had greater valgus angles (p = .003) and moments (p = .026) at MGRFz compared to adults. Females had greater (p = .016) valgus moments than males, but similar valgus angles at MGRFz. It will be important to ensure that as both boys and girls progress through puberty they develop an ability to offset high valgus moments and land with good lower extremity alignment

Loading rate in self-initiated vertical jump landings: developmental and gender comparisons

The study compared gender and developmental differences in vertical loading rate upon a two-footed landing from a self-initiated VJ. Fifty-seven subjects grouped by age (pre-pubescent (8-11 yrs); post-pubescent (19-29 yrs)) and gender consented to participate. Subjects jumped for a ball set at 50% of their maximum VJ height, and landed on two feet, facing forward, with only their dominant foot on the force plate. Motion analysis (3-D) and ground reaction force (GRF) data were collected. Statistical analyses indicated significant developmental differences in vertical loading rate normalized to kinetic energy, but no gender differences. Children may have higher loading rates because they lack the experience, strength, and associated neuromuscular patterns that prepare them to modulate force as adults do

KNEE VALGUS IN SELF-INITIATED VERTICAL JUMP LANDINGS: DEVELOPMENTAL AND GENDER COMPARISIONS

The study examined gender and developmental differences in knee valgus angle and external knee valgus moment at the time of maximal vertical ground reaction force (MGRFz) in self-initiated vertical jump (VJ) landings. Fifty-six subjects grouped by age (pre-pubescent (8-11 yrs); post-pubescent (19-29 yrs)) and gender jumped for a ball set at 50% of their maximum VJ height then landed on two feet with only their dominant foot on the force plate. Statistical analyses of motion analysis (3-D) and GRF data showed that children had greater valgus angles (p = .003) and moments (p = .026) at MGRFz compared to adults. Females had greater (p = .016) valgus moments than males, but similar valgus angles at MGRFz. It will be important to ensure that as both boys and girls progress through puberty they develop an ability to offset high valgus moments and land with good lower extremity alignment

LOADING RATE IN SELF-INITIATED VERTICAL JUMP LANDINGS: DEVELOPMENTAL AND GENDER COMPARISONS

The study compared gender and developmental differences in vertical loading rate upon a two-footed landing from a self-initiated VJ. Fifty-seven subjects grouped by age (pre-pubescent (8-11 yrs); post-pubescent (19-29 yrs)) and gender consented to participate. Subjects jumped for a ball set at 50% of their maximum VJ height, and landed on two feet, facing forward, with only their dominant foot on the force plate. Motion analysis (3-D) and ground reaction force (GRF) data were collected. Statistical analyses indicated significant developmental differences in vertical loading rate normalized to kinetic energy, but no gender differences. Children may have higher loading rates because they lack the experience, strength, and associated neuromuscular patterns that prepare them to modulate force as adults do

Spacecraft Geometry Effects on Kinetic Impactor Missions

The DART (Double Asteroid Redirection Test) mission will impact a spacecraft on the secondary (Dimorphos) of the binary asteroid system Didymos in 2022 September, with the goal of altering the orbital period of Dimorphos about Didymos sufficiently to be observed from ground-based observations. Numerical impact modeling is a crucial component in understanding the outcome of the DART experiment, and while many have investigated the effects of target properties, such as material strength and porosity (which remain unknown), an often overlooked factor is the importance of accurately representing the spacecraft itself in such models. Most impact modeling to date has considered simple impactor geometries such as a solid uniform sphere, but in reality the spacecraft is a complex shape full of different components, open spaces, and thin walled structures. At a minimum, a simple solid representation underestimates the surface area of the impact: for a small body such as Dimorphos (approximately 160 m in diameter), the difference between a spacecraft spanning 20 m (including solar arrays) impacting and a sub-1 m idealized shape may be important. In this paper, we compare models impacting high-fidelity models of the spacecraft based on the CAD geometry with various simplified impactors, in order to assess the potential importance of this effect. We find that the difference between the simplest impactor geometries (such as a uniform sphere) and the real spacecraft is measurable, and has an interesting dependence on the material properties of the asteroid itself

Cardioplastic Approach to Omental Flap Coverage for Severe Aortic Root Infections in the Opioid Era

Aortic root abscesses are severe sequelae of endocarditis that clinically manifest as life-threatening infection. As the opioid epidemic continues to yield a national crisis, the incidence and severity of this disease process have increased. Reconstruction of the aortic root is a challenging undertaking and carries the risk of recurrent infection. The omentum has an established reputation as a reliable flap in thoracic reconstruction, given its amorphous form and immunogenic properties, but it has not been utilized for aortic root infections. We present a novel indication for the omental flap using a cardioplastic approach in coverage of aortic root reconstruction. Four patients were treated with pedicled omental flap coverage after aortic root reconstruction. All patients had successful flap healing with no evidence of recurrent infection. This series demonstrates the technical feasibility and clinical utility for providing soft tissue coverage and antimicrobial protection when used in aortic root reconstruction

Observation of reduced thermal conductivity in a metal-organic framework due to the presence of adsorbates

Whether the presence of adsorbates increases or decreases thermal conductivity in metal-organic frameworks (MOFs) has been an open question. Here we report observations of thermal transport in the metal-organic framework HKUST-1 in the presence of various liquid adsorbates: water, methanol, and ethanol. Experimental thermoreflectance measurements were performed on single crystals and thin films, and theoretical predictions were made using molecular dynamics simulations. We find that the thermal conductivity of HKUST-1 decreases by 40 – 80% depending on the adsorbate, a result that cannot be explained by effective medium approximations. Our findings demonstrate that adsorbates introduce additional phonon scattering in HKUST-1, which particularly shortens the lifetimes of low-frequency phonon modes. As a result, the system thermal conductivity is lowered to a greater extent than the increase expected by the creation of additional heat transfer channels. Finally, we show that thermal diffusivity is even more greatly reduced than thermal conductivity by adsorption

DPP6 regulation of dendritic morphogenesis impacts hippocampal synaptic development

Dipeptidyl-peptidase 6 is an auxiliary subunit of Kv4-mediated A-type K+ channels that, in addition to enhancing channel surface expression, potently accelerates their kinetics. The dipeptidyl-peptidase 6 gene has been associated with a number of human central nervous system disorders including autism spectrum disorders and schizophrenia. Here we employ knockdown and genetic deletion of dipeptidyl-peptidase 6 to reveal its importance for the formation and stability of dendritic filopodia during early neuronal development. We find that the hippocampal neurons lacking dipeptidyl-peptidase 6 show a sparser dendritic branching pattern along with fewer spines throughout development and into adulthood. In electrophysiological and imaging experiments, we show that these deficits lead to fewer functional synapses and occur independently of the potassium channel subunit Kv4.2. We report that dipeptidyl-peptidase 6 interacts with a filopodia-associated myosin as well as with fibronectin in the extracellular matrix. dipeptidyl-peptidase 6 therefore has an unexpected but important role in cell adhesion and motility, impacting the hippocampal synaptic development and function