Jump Performance and its Relationship with Lower Body Joint Kinetics and Kinematics in Children with Cerebral Palsy.

PURPOSE: The aim was to quantify jump performance in children with cerebral palsy (CP) and determine if the expected deficit is related to their lower-body-joint kinetics and kinematics. METHODS: Twenty-four ambulatory (n = 17 level I and 7 level II in the Gross Motor Function Classification System) children with spastic CP (n = 13 unilateral and 11 bilateral) and 24 age-, sex-, and race-matched typically developing controls were studied. Jump height and peak power and range of motion at the hip, knee, and ankle of the more affected limb in children with CP and the nondominant limb in controls were assessed during a countermovement jump using three-dimensional motion capture and a force platform. RESULTS: Compared to controls, children with CP had lower jump height (33%, Cohen's d (d) = 1.217), peak power at the knee (39%, d = 1.013) and ankle (46%, d = 1.687), and range of motion at the hip (32%, d = 1.180), knee (39%, d = 2.067), and ankle (46%, d = 3.195; all p < 0.001). Jump height was positively related to hip, knee, and ankle power and range of motion in children with CP (rs range = 0.474-0.613, p < 0.05), and hip and ankle power and knee and ankle range of motion in controls (rs range = 0.458-0.630, p < 0.05). The group difference in jump height was no longer detected when ankle joint power, ankle range of motion, or knee range of motion was statistically controlled (p > 0.15). CONCLUSIONS: Jump performance is compromised in children with CP and is associated with low power generation and range of motion in the lower limb, especially at the ankle.

Effects of Long-duration Microgravity and Gravitational Transitions on Fine Motor Skills.

OBJECTIVE: Assess the effects of long-duration microgravity and gravitational transitions on fine motor skills using a tablet-based test battery of four fine motor tasks: Pointing, Dragging, Shape Tracing, and Pinch-Rotate. BACKGROUND: While there have been some studies on fine motor skills in microgravity, few have measured the fine motor skills that are core components of interaction with computer-based devices, and none have measured performance systematically, to include preflight, inflight, and postflight space mission time periods. METHODS: Seven astronauts completed the Fine Motor Skills test battery 30-40 times before, during, and up to 30 days after standard duration International Space Station missions, while a matching set of seven ground-based control participants also completed the battery over a comparable period of time. Response time and accuracy were the primary outcome measures. RESULTS: Relative to controls, astronauts experienced fine motor skill decrements at gravitational transitions (first week on orbit, and first month post landing). No decrements were found inflight after the first week of adaptation. CONCLUSION: Gravitational transitions appear to negatively impact fine motor skills needed to operate small controls with accuracy, such as those on touchscreen interfaces. This raises concerns for future long-duration crewmembers who will land on a planetary surface and need to perform critical tasks accurately, such as configuring spacesuits, powering up a habitat, or teleoperating rovers. APPLICATION: Results from this study highlight the need for confirmatory research, and the possible need for countermeasure development. The Fine Motor Skills test battery may have application outside of NASA as a fine motor skills diagnostic screening, rehabilitation, or readiness-to-perform tool.

Synthesis and Characterization of Dye-Doped Au@SiO2 Core-Shell Nanoparticles for Super-Resolution Fluorescence Microscopy.

Dye-doped nanoparticles have been investigated as bright, fluorescent probes for localization-based super-resolution microscopy. Nanoparticle size is important in super-resolution microscopy to get an accurate size of the object of interest from image analysis. Due to their self-blinking behavior and metal-enhanced fluorescence (MEF), Ag@SiO2 and Au@Ag@SiO2 nanoparticles have shown promise as probes for localization-based super-resolution microscopy. Here, several noble metal-based dye-doped core-shell nanoparticles have been investigated as self-blinking nanomaterial probes. It was observed that both the gold- and silver-plated nanoparticle cores exhibit weak luminescence under certain conditions due to the surface plasmon resonance bands produced by each metal, and the gold cores exhibit blinking behavior which enhances the blinking and fluorescence of the dye-doped nanoparticle. However, the silver-plated nanoparticle cores, while weakly luminescent, did not exhibit any blinking; the dye-doped nanoparticle exhibited the same behavior as the core fluorescent, but did not blink. Because of the blinking behavior, stochastic optical reconstruction microscopy (STORM) super-resolution analysis was able to be performed with performed on the gold core nanoparticles. A preliminary study on the use of these nanoparticles for localization-based super-resolution showed that these nanoparticles are suitable for use in STORM super resolution. Resolution enhancement was two times better than the diffraction limited images, with core sizes reduced to 15 nm using the hybrid Au-Ag cores.

Increased Basal Ganglia Modulatory Effective Connectivity Observed in Resting-State fMRI in Individuals With Parkinson's Disease.

Alterations to interactions between networked brain regions underlie cognitive impairment in many neurodegenerative diseases, providing an important physiological link between brain structure and cognitive function. Previous attempts to characterize the effects of Parkinson's disease (PD) on network functioning using resting-state functional magnetic resonance imaging (rs-fMRI), however, have yielded inconsistent and contradictory results. Potential problems with prior work arise in the specifics of how the area targeted by the diseases (the basal ganglia) interacts with other brain regions. Specifically, current computational models point to the fact that the basal ganglia contributions should be captured with modulatory (i.e., second-order) rather than direct (i.e., first-order) functional connectivity measures. Following this hypothesis, a principled but manageable large-scale brain architecture, the Common Model of Cognition, was used to identify differences in basal ganglia connectivity in PD by analyzing resting-state fMRI data from 111 participants (70 patients with PD; 41 healthy controls) using Dynamic Causal Modeling (DCM). Specifically, the functional connectivity of the basal ganglia was modeled as two second-level, modulatory connections that control projections from sensory cortices to the prefrontal cortex, and from the hippocampus and medial temporal lobe to the prefrontal cortex. We then examined group differences between patients with PD and healthy controls in estimated modulatory effective connectivity in these connections. The Modulatory variant of the Common Model of Cognition outperformed the Direct model across all subjects. It was also found that these second-level modulatory connections had higher estimates of effective connectivity in the PD group compared to the control group, and that differences in effective connectivity were observed for all direct connections between the PD and control groups.We make the case that accounting for modulatory effective connectivity better captures the effects of PD on network functioning and influences the interpretation of the directionality of the between-group results. Limitations include that the PD group was scanned on dopaminergic medication, results were derived from a reasonable but small number of individuals and the ratio of PD to healthy control participants was relatively unbalanced. Future research will examine if the observed effect holds for individuals with PD scanned off their typical dopaminergic medications.

Self-assembly of reversed bilayer vesicles through pnictogen bonding: water-stable supramolecular nanocontainers for organic solvents.

A new air and moisture stable antimony thiolate compound has been prepared that spontaneously forms stable hollow vesicles. Structural data reveals that pnictogen bonding drives the self-assembly of these molecules into a reversed bilayer. The ability to make these hollow, spherical, and chemically and temporally stable vesicles that can be broken and reformed by sonication allows these systems to be used for encapsulation and compartmentalisation in organic media. This was demonstrated through the encapsulation and characterization of several small organic reporter molecules.

Mental Health and Timing of Gender-Affirming Care.

BACKGROUND: Gender-incongruent (GI) youth have high rates of mental health problems. Although gender-affirming medical care (GAMC) provides psychological benefit, some GI youth present to care at older ages. Whether a relationship exists between age of presentation to GAMC and mental health difficulties warrants study. METHODS: A cross-sectional chart review of patients presenting to GAMC. Subjects were classified a priori as younger presenting youth (YPY) (<15 years of age at presentation) or older presenting youth (OPY) (≥15 years of age). Self-reported rates of mental health problems and medication use were compared between groups. Binary logistic regression analysis was used to identify determinants of mental health problems. Covariates included pubertal stage at presentation, social transition status, and assigned sex. RESULTS: Of 300 youth, there were 116 YPY and 184 OPY. After presentation, more OPY than YPY reported a diagnosis of depression (46% vs 30%), had self-harmed (40% vs 28%), had considered suicide (52% vs 40%), had attempted suicide (17% vs 9%), and required psychoactive medications (36% vs 23%), with all P < .05. After controlling for covariates, late puberty (Tanner stage 4 or 5) was associated with depressive disorders (odds ratio 5.49; 95% confidence interval [CI]: 1.14-26.32) and anxiety disorders (odds ratio 4.18 [95% CI: 1.22-14.49]), whereas older age remained associated only with psychoactive medication use (odd ratio 1.31 [95% CI: 1.05-1.63]). CONCLUSIONS: Late pubertal stage and older age are associated with worse mental health among GI youth presenting to GAMC, suggesting that this group may be particularly vulnerable and in need of appropriate care.

The effects of visual magnification and physical movement scale on the manipulation of a tool with indirect vision.

Modern tools often separate the visual and physical aspects of operation, requiring users to manipulate an instrument while viewing the results indirectly on a display. This can pose usability challenges particularly in applications, such as laparoscopic surgery, that require a high degree of movement precision. Magnification used to augment the view and, theoretically, enable finer movements, may introduce other visual-motor disruptions due to the apparent speed of the visual motion on screen (i.e., motion scaling). In this research, we sought to better understand the effects of visual magnification on human movement performance and control in operating a tool via indirect vision. Ten adult participants manipulated a computer mouse to direct a pointer to targets on a display. Results (Experiment 1) showed that, despite increased motion scaling, magnification of the view on screen enabled higher precision control of the mouse pointer. However, the relative effectiveness of visual magnification ultimately depended on the scale of the physical movement, and more specifically the precision limits of the whole-hand grip afforded by the mouse. When the physical scale of the hand/mouse movement was reduced (Experiment 2), fine-precision control began to reach its limits, even at full magnification. The role of magnification can thus be understood as "amplifying" the particular skill level afforded by the effecting limb. These findings suggest a fruitful area for future research is the optimization of hand-control interfaces of tools to maximize movement precision.

Kinematic analysis of multiple constraints on a pointing task.

The current experiment suggests that the speed/accuracy tradeoff is composed of two classes of constraints, effector and task. We examined the effects of movement distance, target size, orientation of the movement in the workspace, and C-D gain on the kinematics of discrete pointing movements made with computer mouse. It was found that target size influenced the shape of velocity profiles by elongating the duration of the corrective sub-movement phase, while movement distance scaled the entire velocity curve without affecting its shape. C-D gain and orientation of the movement exhibited two kinds of effects: an overall scaling of the velocity curve and a change in its shape. We conclude that target size is a task constraint and movement distance is an effector constraint, while movement orientation exhibited characteristics of both. C-D gain by itself was not a constraint, but interacted with both task and effector constrains. These results highlight the roles of biomechanical and information processing factors in the speed/accuracy tradeoff.