Human-Delivered Brushstroke Characterization using an Instrumented Brush Focused on Torque.

Pleasant brush therapies may benefit those with autism, trauma, and anxiety. While studies monitor brushing velocity, hand-delivery of brush strokes introduces variability. Detailed measurements of human-delivered brushing physics may help understand such variability and subsequent impact on receivers' perceived pleasantness. Herein, we instrument a brush with multi-axis force and displacement sensors to measure their physics as 12 participants pleasantly stroke a receiver's forearm. Algorithmic procedures identify skin contact, and define four stages of arrival, stroke, departure, and airtime between strokes. Torque magnitude, rather than force, is evaluated as a metric to minimize inertial noise, as it registers brush bend and orientation. Overall, the results of the naturally delivered brushing experiments indicate force and velocity values in the range of 0.4 N and 3-10 cm/s, in alignment with prior work. However, we observe significant variance between brushers across velocity, force, torque, and brushstroke length. Upon further analysis, torque and force measures are correlated, yet torque provides distinct information from velocity. In evaluating the receiver's response to individual differences between brushers of the preliminary case study, higher pleasantness is tied to lower mean torque, and lower instantaneous variance over the stroke duration. Torque magnitude appears to complement velocity's influence on perceived pleasantness.

Optical Measurements of the Skin Surface to Infer Bilateral Distinctions in Myofascial Tissue Stiffness.

About half the U.S. adult population suffers from chronic neuromusculoskeletal pain. While its evaluation and treatment are widely addressed by therapies using soft tissue manipulation (STM), their efficacy is based upon clinician judgment. Robust biomarkers are needed to quantify the effects of STM on patient outcomes. Among noninvasive methods to quantify the mechanics of myofascial tissue, most are limited to small (<10 mm2), localized regions of interest. In contrast, we develop an approach to optically simultaneously measure a larger (~100 cm2) field of deformation at the skin surface. Biomarkers based on skin lateral mobility are derived to infer distinctions in myofascial tissue stiffness. In specific, three cameras track ink speckles whose fields of deformation and stretch are resolved with digital image correlation. Their ability to differentiate bilateral distinctions of the cervicothoracic region is evaluated with four participants, as a licensed clinician performs STM. The results indicate that the optically derived surface biomarkers can differentiate bilateral differences in skin mobility, with trend directions within a participant similar to measurements with an instrumented force probe. These findings preliminarily suggest skin surface measurements are capable of inferring underlying myofascial tissue stiffness, although further confirmation will require a larger, more diverse group of participants.

MR Imaging Correlates for Molecular and Mutational Analyses in Children with Diffuse Intrinsic Pontine Glioma.

BACKGROUND AND PURPOSE: Recent advances in molecular techniques have characterized distinct subtypes of diffuse intrinsic pontine gliomas. Our aim was the identification of MR imaging correlates of these subtypes. MATERIALS AND METHODS: Initial MRIs from subjects with diffuse intrinsic pontine gliomas recruited for a prospective clinical trial before treatment were analyzed. Retrospective imaging analyses included FLAIR/T2 tumor volume, tumor volume enhancing, the presence of cyst and/or necrosis, median, mean, mode, skewness, kurtosis of ADC tumor volume based on FLAIR, and enhancement at baseline. Molecular subgroups based on EGFR and MGMT mutations were established. Histone mutations were also determined (H3F3A, HIST1H3B, HIST1H3C). Univariate Cox proportional hazards regression was used to test the association of imaging predictors with overall and progression-free survival. Wilcoxon rank sum, Kruskal-Wallis, and Fisher exact tests were used to compare imaging measures among groups. RESULTS: Fifty patients had biopsy and MR imaging. The median age at trial registration was 6 years (range, 3.3-17.5 years); 52% were female. On the basis of immunohistochemical results, 48 patients were assigned to 1 of 4 subgroups: 28 in MGMT-/epidermal growth factor receptor (EGFR)-, 14 in MGMT-/EGFR+, 3 in MGMT+/EGFR-, and 3 in MGMT+/EGFR+. Twenty-three patients had histone mutations in H3F3A, 8 in HIST1H3B, and 3 in HIST1H3C. Enhancing tumor volume was near-significantly different across molecular subgroups (P = .04), after accounting for the false discovery rate. Tumor volume enhancing, median, mode, skewness, and kurtosis ADC T2-FLAIR/T2 were significantly different (P ≤ .048) between patients with H3F3A and HIST1H3B/C mutations. CONCLUSIONS: MR imaging features including enhancement and ADC histogram parameters are correlated with molecular subgroups and mutations in children with diffuse intrinsic pontine gliomas.

Multicentennial record of Labrador Sea primary productivity and sea-ice variability archived in coralline algal barium.

Accelerated warming and melting of Arctic sea-ice has been associated with significant increases in phytoplankton productivity in recent years. Here, utilizing a multiproxy approach, we reconstruct an annually resolved record of Labrador Sea productivity related to sea-ice variability in Labrador, Canada that extends well into the Little Ice Age (LIA; 1646 AD). Barium-to-calcium ratios (Ba/Ca) and carbon isotopes (δ13C) measured in long-lived coralline algae demonstrate significant correlations to both observational and proxy records of sea-ice variability, and show persistent patterns of co-variability broadly consistent with the timing and phasing of the Atlantic Multidecadal Oscillation (AMO). Results indicate reduced productivity in the Subarctic Northwest Atlantic associated with AMO cool phases during the LIA, followed by a step-wise increase from 1910 to present levels-unprecedented in the last 363 years. Increasing phytoplankton productivity is expected to fundamentally alter marine ecosystems as warming and freshening is projected to intensify over the coming century.

Coralline algal barium as indicator for 20th century northwestern North Atlantic surface ocean freshwater variability.

During the past decades climate and freshwater dynamics in the northwestern North Atlantic have undergone major changes. Large-scale freshening episodes, related to polar freshwater pulses, have had a strong influence on ocean variability in this climatically important region. However, little is known about variability before 1950, mainly due to the lack of long-term high-resolution marine proxy archives. Here we present the first multidecadal-length records of annually resolved Ba/Ca variations from Northwest Atlantic coralline algae. We observe positive relationships between algal Ba/Ca ratios from two Newfoundland sites and salinity observations back to 1950. Both records capture episodical multi-year freshening events during the 20th century. Variability in algal Ba/Ca is sensitive to freshwater-induced changes in upper ocean stratification, which affect the transport of cold, Ba-enriched deep waters onto the shelf (highly stratified equals less Ba/Ca). Algal Ba/Ca ratios therefore may serve as a new resource for reconstructing past surface ocean freshwater changes.

Toward improving patient safety through voluntary peer-to-peer assessment.

Health care has primarily used retrospective review approaches to identify and mitigate hazards, with little evidence of measurable and sustained improvements in patient safety. Conversely, the nuclear power industry has used a prospective peer-to-peer (P2P) assessment process grounded in open information exchange and cooperative organizational learning to realize substantial and sustainable improvements in safety. In comparing approaches, it is evident that health care's sluggish progress stems from weaknesses in hazard identification and mitigation and in organizational learning. This article proposes creating and implementing a structured prospective P2P assessment model in health care, similar to that used in the nuclear power industry, to accelerate improvements in patient safety.

Elastic energy storage in the mantis shrimp's fast predatory strike.

Storage of elastic energy is key to increasing the power output of many biological systems. Mantis shrimp (Stomatopoda) must store considerable elastic energy prior to their rapid raptorial strikes; however, little is known about the dynamics and location of elastic energy storage structures in this system. We used computed tomography (CT) to visualize the mineralization patterns in Gonodactylaceus falcatus and high speed videography of Odontodactylus scyllarus to observe the dynamics of spring loading. Using a materials testing apparatus, we measured the force and work required to contract the elastic structures in G. falcatus. There was a positive linear correlation between contraction force and contraction distance; alternative model tests further supported the use of a linear model. Therefore, we modeled the system as a Hookean spring. The force required to fully compress the spring was positively correlated with body mass and appendage size, but the spring constant did not scale with body size, suggesting a possible role of muscle constraints in the scaling of this system. One hypothesized elastic storage structure, the saddle, only contributed approximately 11% of the total measured force, thus suggesting that primary site of elastic energy storage is in the mineralized ventral bars found in the merus segment of the raptorial appendages. Furthermore, the intact system exhibited 81% resilience and severing the saddle resulted in a non-significant reduction to 77% resilience. The remarkable shapes and mineralization patterns that characterize the mantis shrimp's raptorial appendage further reveal a highly integrated mechanical power amplification system based on exoskeletal elastic energy storage.

The effect and safety of short-term creatine supplementation on performance of push-ups.

The effects of short-term oral creatine (Cr) supplementation on exercise performance and on blood pressure and renal function were assessed. Thirty-five healthy, active duty, U.S. Army volunteers (20 men and 15 women; age, 22-36 years) at Fort Sam Houston, Texas, supplemented their diet for 7 days with 20 g/day of either Cr or taurine (as placebo). There was no significant difference in 2-minute push-up counts between the Cr and taurine groups from before to after supplementation (p = 0.437; power = 0.98). The Cr group demonstrated a significant increase in serum creatinine levels (p < 0.001), compared with the taurine group, and this increase could be misinterpreted as impairment of renal function. No adverse changes in blood pressure, body composition, weight, or serum Cr phosphokinase levels were observed. We conclude that short-term Cr supplementation appears to be safe but does not enhance push-up performance.