Punishment Leads to Greater Sensorimotor Learning But Less Movement Variability Compared to Reward.

When a musician practices a new song, hitting a correct note sounds pleasant while striking an incorrect note sounds unpleasant. Such reward and punishment feedback has been shown to differentially influence the ability to learn a new motor skill. Recent work has suggested that punishment leads to greater movement variability, which causes greater exploration and faster learning. To further test this idea, we collected 102 participants over two experiments. Unlike previous work, in Experiment 1 we found that punishment did not lead to faster learning compared to reward (n = 68), but did lead to a greater extent of learning. Surprisingly, we also found evidence to suggest that punishment led to less movement variability, which was related to the extent of learning. We then designed a second experiment that did not involve adaptation, allowing us to further isolate the influence of punishment feedback on movement variability. In Experiment 2, we again found that punishment led to significantly less movement variability compared to reward (n = 34). Collectively our results suggest that punishment feedback leads to less movement variability. Future work should investigate whether punishment feedback leads to a greater knowledge of movement variability and or increases the sensitivity of updating motor actions.

Visual accuracy dominates over haptic speed for state estimation of a partner during collaborative sensorimotor interactions.

We routinely have physical interactions with others, whether it be handing someone a glass of water or jointly moving a heavy object together. These sensorimotor interactions between humans typically rely on visual feedback and haptic feedback. Recent single-participant studies have highlighted that the unique noise and time delays of each sense must be considered to estimate the state, such as the position and velocity, of one's own movement. However, we know little about how visual feedback and haptic feedback are used to estimate the state of another person. Here, we tested how humans utilize visual feedback and haptic feedback to estimate the state of their partner during a collaborative sensorimotor task. Across two experiments, we show that visual feedback dominated haptic feedback during collaboration. Specifically, we found that visual feedback led to comparatively lower task-relevant movement variability, smoother collaborative movements, and faster trial completion times. We also developed an optimal feedback controller that considered the noise and time delays of both visual feedback and haptic feedback to estimate the state of a partner. This model was able to capture both lower task-relevant movement variability and smoother collaborative movements. Taken together, our empirical and modeling results support the idea that visual accuracy is more important than haptic speed to perform state estimation of a partner during collaboration.NEW & NOTEWORTHY Physical collaboration between two or more individuals involves both visual and haptic feedback. Here, we investigated how visual and haptic feedback is used to estimate the movements of a partner during a collaboration task. Our experimental and computational modeling results parsimoniously support the notion that greater visual accuracy is more important than faster yet noisier haptic feedback when estimating the state of a partner.

Controlled Release of Flurbiprofen from 3D-Printed and Supercritical Carbon Dioxide Processed Methacrylate-Based Polymer.

The ability to engineer and predict drug release behavior during treatment is critical to the design and implementation of effective drug delivery systems. In this study, a drug delivery system consisting of a methacrylate-based polymer and flurbiprofen was studied, and its release profile in a controlled phosphate-buffered saline solution was characterized. The polymer, which was 3D printed and processed in supercritical carbon dioxide under different temperature and pressure settings, showed sustained drug release over a prolonged period. A computer algorithm was used to determine the drug release time duration before reaching steady state and the maximum drug release at steady state. Several empirical models were applied to fit the release kinetic data to gain information about the drug release mechanism. The diffusion coefficients for each system were also estimated using Fick's law. Based on the results, the influence of supercritical carbon dioxide processing conditions on the diffusion behavior is interpreted, providing insights into the effective and tunable design of drug delivery systems for targeted treatment specifications.

Interspecific variation in bristle number on forewings of tiny insects does not influence clap-and-fling aerodynamics.

Miniature insects must overcome significant viscous resistance in order to fly. They typically possess wings with long bristles on the fringes and use a clap-and-fling mechanism to augment lift. These unique solutions to the extreme conditions of flight at tiny sizes (<2 mm body length) suggest that natural selection has optimized wing design for better aerodynamic performance. However, species vary in wingspan, number of bristles (n) and bristle gap (G) to diameter (D) ratio (G/D). How this variation relates to body length (BL) and its effects on aerodynamics remain unknown. We measured forewing images of 38 species of thrips and 21 species of fairyflies. Our phylogenetic comparative analyses showed that n and wingspan scaled positively and similarly with BL across both groups, whereas G/D decreased with BL, with a sharper decline in thrips. We next measured aerodynamic forces and visualized flow on physical models of bristled wings performing clap-and-fling kinematics at a chord-based Reynolds number of 10 using a dynamically scaled robotic platform. We examined the effects of dimensional (G, D, wingspan) and non-dimensional (n, G/D) geometric variables on dimensionless lift and drag. We found that: (1) increasing G reduced drag more than decreasing D; (2) changing n had minimal impact on lift generation; and (3) varying G/D minimally affected aerodynamic forces. These aerodynamic results suggest little pressure to functionally optimize n and G/D. Combined with the scaling relationships between wing variables and BL, much wing variation in tiny flying insects might be best explained by underlying shared growth factors.

Outcome of revisional bariatric surgery for insufficient weight loss after laparoscopic Roux-en-Y gastric bypass: an observational study.

BACKGROUND: Insufficient weight loss or secondary weight regain with or without recurrence of comorbidity can occur years after laparoscopic Roux en Y gastric bypass (LRYGB). In selected patients, increasing restriction or adding malabsorption may be a surgical option after conservative measures failed. OBJECTIVES: Evaluation of short and long term results of revisional surgery for insufficient weight loss or weight regain after LRYGB. SETTING: Tertiary hospital. METHODS: Retrospective analysis of prospectively collected data from a cohort of 1150 LRYGB patients. Included were patients, who underwent revisional bariatric surgery after LRYGB for insufficient weight loss with a follow-up of minimal 1 year. RESULTS: Fifty-four patients were included in the analysis. After an interdisciplinary evaluation, patients with insufficient weight loss, signs of dumping syndrome, and lacking restriction were offered a nonadjustable band around the pouch (banded group, n = 34) and patients with sufficient restriction, excellent compliance, and adherence were offered a revision to laparoscopic biliopancreatic diversion (BPD group, n = 20). The revisional procedure was performed 3.3 ± 2.3 years after LRYGB in the banded-group and after 6.4 ± 4.3 years in the BPD group (P = .001). Mean body mass index at the time of the primary bariatric procedure was 41.7 ± 6.2 kg/m2 in the banded group and 45.2 ± 8.2 kg/m2 in the BPD group (P = .08); minimal body mass index between both operations was 29.1 ± 4.7 kg/m2 in the banded group and 36.5 ± 9.4 kg/m2 in the BPD group, and, at the time of revisional surgery, 31.4 ± 5.5 kg/m2 in the banded group and 40.8 ± 6.7 kg/m2 in the BPD group (P = .0001). The mean body mass index difference 1 year after revisional surgery was 1.3 ± 3.0 kg/m2 in the banded group and 6.7 ± 4.5 kg/m2 in the BPD group (P = .01). In the banded group, 11 patients (32.4%) needed removal of the band, 4 patients (11.8%) needed an adjustment, and 4 patients (11.8%) were later converted to BPD. In the BPD group, 2 (10.0%) patients needed revision for severe protein malabsorption. CONCLUSIONS: Insufficient weight loss or secondary weight regain after LRYGB is a rare indication for revisional surgery. Banded bypass has modest results for additional weight loss but can help patients suffering from dumping. In very carefully selected cases, BPD can achieve additional weight loss with acceptable complication rate but higher risk for reoperation. Future "adjuvant medical treatments," such as glucagon-like peptide 1 analogues and other pharmacologic treatment options could be an alternative for achieving additional weight loss and better metabolic response.

In vitro influence of polyclonal anti-thymocyte globulins on leukocyte expression of adhesion molecules.

OBJECTIVES: Polyclonal anti-thymocyte globulins (ATGs) are drugs used in the induction of immunosuppression, in the treatment of acute rejection, and in the therapy of hematologic disorders. Treatment with ATGs can produce adverse effects due to cross-reacting antibodies directed against nonmyeloid cells. This study sought to evaluate the interaction of ATGs and some adhesion molecules expressed on the surface of neutrophils and lymphocytes. MATERIALS AND METHODS: We determined the effects of different doses of 3 polyclonal ATGs on the activation and expression of lymphocyte and neutrophil adhesion molecules in whole blood by means of flow cytometry. RESULTS: ATG treatment reduced the percentage of lymphocytes gated for CD18 and CD62L, as well as the expression of CD11b, CD18, and CD62L in a dose-dependent manner. ATGs modulated the percentage of gated neutrophils for CD18. Although ATG treatment did not affect CD11b or CD62L gating in neutrophils, it did regulate expression of these adhesion markers. CONCLUSIONS: Our results show that ATGs can modify the expression levels of some of the main leukocyte adhesion molecules that are responsible for the characteristic cellular adhesion after ischemia/ reperfusion. These properties of ATGs may contribute to reduced leukocyte infiltration after solid-organ transplantation.