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Abstract Satellite observations of snow‐covered regions in the microwave range have the potential to retrieve essential climate variables such as snow height. This requires a precise understanding of how microwave scattering is linked to snow microstructural properties (density, grain size, grain shape and arrangement). This link has so far relied on empirical adjustments of the theories, precluding the development of robust retrieval algorithms. Here we solve this problem by introducing a new microstructural parameter able to consistently predict scattering. This “microwave grain size” is demonstrated to be proportional to the measurable optical grain size and to a new factor describing the chord length dispersion in the microstructure, a geometrical property known as polydispersity. By assuming that the polydispersity depends on the snow grain type only, we retrieve its value for rounded and faceted grains by optimization of microwave satellite observations in 18 Antarctic sites, and for depth hoar in 86 Canadian sites using ground‐based observations. The value for the convex grains (0.6) compares favorably to the polydispersity calculated from 3D micro‐computed tomography images for alpine grains, while values for depth hoar show wider variations (1.2–1.9) and are larger in Canada than in the Alps. Nevertheless, using one value for each grain type, the microwave observations in Antarctica and in Canada can be simulated from in‐situ measurements with good accuracy with a fully physical model. These findings improve snow scattering modeling, enabling future more accurate uses of satellite observations in snow hydrological and meteorological applications.

The French critical zone initiative, called OZCAR (Observatoires de la Zone Critique–Application et Recherche or Critical Zone Observatories–Application and Research) is a National Research Infrastructure (RI). OZCAR-RI is a network of instrumented sites, bringing together 21 pre-existing research observatories monitoring different compartments of the zone situated between “the rock and the sky,” the Earth’s skin or critical zone (CZ), over the long term. These observatories are regionally based and have specific initial scientific questions, monitoring strategies, databases, and modeling activities. The diversity of OZCAR-RI observatories and sites is well representative of the heterogeneity of the CZ and of the scientific communities studying it. Despite this diversity, all OZCAR-RI sites share a main overarching mandate, which is to monitor, understand, and predict (“earthcast”) the fluxes of water and matter of the Earth’s near surface and how they will change in response to the “new climatic regime.” The vision for OZCAR strategic development aims at designing an open infrastructure, building a national CZ community able to share a systemic representation of the CZ , and educating a new generation of scientists more apt to tackle the wicked problem of the Anthropocene. OZCAR articulates around: (i) a set of common scientific questions and cross-cutting scientific activities using the wealth of OZCAR-RI observatories, (ii) an ambitious instrumental development program, and (iii) a better interaction between data and models to integrate the different time and spatial scales. Internationally, OZCAR-RI aims at strengthening the CZ community by providing a model of organization for pre-existing observatories and by offering CZ instrumented sites. OZCAR is one of two French mirrors of the European Strategy Forum on Research Infrastructure (eLTER-ESFRI) project.

Introduction: The prevalence of cardiometabolic disease following spinal cord injury is known to be high. However, it is unknown whether engaging in high-intensity exercise, which is advocated by recent guidelines, is beneficial or feasible for these individuals., Objective: To assess the effects of high-intensity, whole-body exercise on the prevalence of cardiometabolic disease in individuals with spinal cord injury., Design: Combination of a randomized controlled trial and an open label intervention study of functional electrical stimulation legs plus arms rowing., Setting: Outpatient academic rehabilitation hospital., Participants: Forty individuals with spinal cord injury, with American Spinal Injury Association (ASIA) impairments scales A-D and neurological levels of injury C1-T12., Intervention: Six months of high-intensity, hybrid-functional electrical stimulation rowing., Main Outcome Measures: Change in VO 2max , serum lipids, and insulin resistance, prevalence of cardiometabolic disease., Results: Individuals averaged 42.1 ± 22.0 minutes of hybrid-functional electrical stimulation rowing a week over an average of 1.69 sessions per week over the 6 months of intervention. This amounted to an average of 170.9 ± 100 km rowed, at a mean heart rate of 82.7% of individualized maximum. Only one of 40 individuals met current exercise guidelines for the full 6 months. VO 2max increased significantly (P < .001), yet prevalence of cardiometabolic disease did not change significantly (decrease from 22.5% to 20%, P = .70). Hemoglobin A1c did decrease significantly over this time (P = .01), although serum lipids and fasting glucose/insulin levels were unchanged. In exploratory subanalyses assessing individuals injured ≤12 months, those with more chronic injuries decreased their triglyceride-to-high-density lipoprotein (HDL) ratio (P = .04), a marker of cardiac mortality. Stratifying by neurological level of injury, individuals with paraplegia had worsened low-density lipoprotein (LDL) level (P = .02) and total cholesterol-to-HDL ratio (P = .04) over the 6-month intervention., Conclusions: Sustained high-intensity exercise with hybrid functional electrical stimulation rowing does not decrease the prevalence of cardiometabolic disease after spinal cord injury., (© 2020 American Academy of Physical Medicine and Rehabilitation.)

Background: Functional electrical stimulation (FES) is widely used to induce functional movements for paralyzed muscles. However, rapid muscle fatigue during FES-induced muscle contractions limits FES clinical efficacy., Objective: To investigate muscle fatigue response across stimulation patterns and frequencies during FES in able-bodied individuals and in those with spinal cord injury (SCI)., Design: Four stimulation protocols combining 20 and 40 Hz average frequency with either constant frequency trains (CFTs) or with doublet frequency trains (DFTs) were applied to the quadriceps of seven adults with SCI and eight able-bodied participants., Setting: A FES-row training laboratory., Participants: Seven individuals with SCI (one female; age range, 25 ± 6 years) and eight age-matched able-bodied participants (one female)., Intervention: None., Main Outcome Measures: Fatigue was defined as the number of contractions until force decreased by 20% from the target level of 25% maximal contraction force. The number of contractions and the stimulation current used during the four stimulation protocols were compared., Results: There was a significant effect of frequency, as well as interaction between group and stimulation pattern (P < .05). In both groups, 20-Hz trains increased the number of contractions to fatigue compared to 40-Hz trains. However, the responses to the pattern of stimulation differed. In the able-bodied participants, CFT increased the number of contractions to fatigue compared to DFT, whereas in those with SCI, DFT increased the number of contractions to fatigue. In fact, DFT resulted in similar number of contractions to fatigue in both populations., Conclusions: These results indicate that DFT at 20 Hz may be a better stimulation protocol to delay fatigue onset in the SCI population than the other three protocols. In addition, this work implies that results from able-bodied persons may not be directly applicable to those with SCI., (© 2019 American Academy of Physical Medicine and Rehabilitation.)

Microfracture repair tissue in young adult humans and in rabbit trochlea is frequently of higher quality than in corresponding ovine or horse models or in the rabbit medial femoral condyle (MFC). This may be related to differences in subchondral properties since repair is initiated from the bone. We tested the hypothesis that subchondral bone from rabbit trochlea and the human MFC are structurally similar. Trochlea and MFC samples from rabbit, sheep, and horse were micro-CT scanned and histoprocessed. Samples were also collected from normal and lesional areas of human MFC. The subchondral bone of the rabbit trochlea was the most similar to human MFC, where both had a relatively thin bone plate and a more porous and less dense character of subchondral bone. MFC from animals all displayed thicker bone plates, denser and less porous bone and thicker trabeculae, which may be more representative of older or osteoarthritic patients, while both sheep trochlear ridges and the horse lateral trochlea shared some structural features with human MFC. Since several cartilage repair procedures rely on subchondral bone for repair, subchondral properties should be accounted for when choosing animal models to study and test procedures that are intended for human cartilage repair., (© 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

The influence of the location of cartilage lesions on cartilage repair outcome is incompletely understood. This study compared cartilage and bone repair in medial femoral condylar (MFC) versus femoral trochlear (TR) defects 3 months after bone marrow stimulation in mature rabbits. Intact femurs from adult rabbits served as controls. Results from quantitative histomorphometry and histological scoring showed that bone marrow stimulation produced inferior soft tissue repair in MFC versus TR defects, as indicated by significantly lower % Fill (p = 0.03), a significant increase in collagen type I immunostaining (p < 0.00001) and lower O'Driscoll scores (p < 0.05). 3D micro-CT analysis showed that repaired TR defects regained normal un-operated values of bone volume fraction, trabecular thickness, and trabecular number, whereas in MFC defects the repaired bone architecture appeared immature and less dense compared to intact un-operated MFC controls (p < 0.0001). Severe medial meniscal damage was found in 28% of operated animals and was strongly correlated with (i) low cartilage defect fill, (ii) incomplete bone repair in MFC, and (iii) with a more posterior defect placement in the weight-bearing region. We conclude that the location of cartilage lesions influences cartilage repair, with better outcome in TR versus MFC defects in rabbits. Meniscal degeneration is associated with cartilage damage., (© 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Absolute protein quantification, i.e. determining protein concentrations in biological samples, is essential to our understanding of biological and physiopathological phenomena. Protein quantification methods based on the use of antibodies are very effective and widely used. However, over the last ten years, absolute protein quantification by mass spectrometry has attracted considerable interest, particularly for the study of systems biology and as part of biomarker development. This interest is mainly linked to the high multiplexing capacity of MS analysis, and to the availability of stable-isotope-labelled standards for quantification. This article describes the details of how to produce, control the quality and use a specific type of standard: Protein Standard Absolute Quantification (PSAQ™) standards. These standards are whole isotopically labelled proteins, analogues of the proteins to be assayed. PSAQ standards can be added early during sample treatment, thus they can correct for protein losses during sample prefractionation and for incomplete sample digestion. Because of this, quantification of target proteins is very accurate and precise using these standards. To illustrate the advantages of the PSAQ method, and to contribute to the increase in its use, selected applications in the biomedical field are detailed here., (Copyright © 2012 John Wiley & Sons, Ltd.)

Objective: To determine the magnitude and range of increases in peak aerobic capacity with hybrid-functional electrical stimulation (FES) rowing versus arms-only rowing in persons with spinal cord injury., Design: Comparison of graded exercise tests for peak responses during FES rowing and arms-only rowing. Preliminary data on adaptations to FES row training were gathered in a subset of individuals., Setting: Outpatient cardiovascular research laboratory., Participants: Six male patients with spinal cord injury (T4-T9, American Spinal Injury Association class A). METHODS OR INTERVENTION: Arms-only rowing was compared with FES rowing, in which the person who is exercising synchronizes the voluntarily controlled upper body movement with the FES-controlled leg movement via stimulation to the paralyzed leg muscles. A subgroup (n = 3) completed at least 6 months of a progressive FES row training exercise program with graded exercise tests every 6 months., Main Outcome Measurements: Peak oxygen consumption, peak ventilation, peak respiratory exchange ratio, peak heart rate, and peak oxygen pulse., Results: Peak oxygen consumption was greater during FES rowing than during arms-only rowing (20.0 ± 1.9 mL/kg/min versus 15.7 ± 1.5 mL/kg/min, P = .01). Peak ventilation was similar, whereas peak respiratory exchange ratio and peak heart rate tended to be lower (P = .14 and P = .19, respectively). As a result, oxygen pulse was greater by 35% during FES rowing. Two of the three persons who completed at least 6 months of FES row training demonstrated increases in aerobic capacity greater than those previously observed in able-bodied individuals., Conclusions: FES rowing may provide a more robust exercise stimulus for persons with spinal cord injury than most options currently available because of the greater aerobic demand., (Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.)

Objective: To describe the relationship between vagally mediated bradycardia and heart rate variability indices in young and older healthy individuals., Design: Cross-sectional, physiologic study., Setting: Outpatient cardiovascular research laboratory., Participants: A total of 34 young (mean age 24 years) and 27 older (mean age 63 years) healthy adults., Methods: Eight bolus injections of atropine sulfate were given intravenously to participants while in a supine position (cumulative doses from 0.4 to 7.2 microg/kg). Each dose was followed by a 3-minute data collection period in which subjects controlled their breathing frequency at a rate of 15 breaths per minute., Main Outcome Measurements: Chronotropic responses were assessed from average RR interval and blood pressure was assessed by automated brachial cuff. Heart rate variability (HRV) indices were calculated to represent both time domain measures (RR interval standard deviation and root mean squared of successive differences) and frequency domain measures (respiratory sinus arrhythmia and total power)., Results: RR interval responses exhibited the expected curvilinear pattern to atropine administration with all subjects exhibiting a bradycardia with at least one dose and RR interval returning to baseline or decreasing in most subjects as atropine dosing progressed. RR interval was closely related to vagotonic atropine dose with an r(2) greater than 0.70 in 89% of subjects. Heart rate variability indices were not consistently correlated with the bradycardic effect of vagotonic atropine and ranged from highly positive to highly negative with almost one-fifth of correlations less than 0.5., Conclusions: The relationship between HRV and vagal tone is likely complex and has a large interindividual variation.

The viability of algal cells immobilized on screens and starved in a water-saturated air stream was studied at the laboratory scale. This new process for wastewater biotreatment has been developed using immobilized cells, which were starved in air, to obtain a high rate of nutrient removal. A unicellular green microalgae, Scenedesmus bicellularis, was isolated from secondary decantation tanks at an urban wastewater treatment plant and grown in a synthetic medium for 12 days. The cells were then concentrated by centrifugation and immobilized on alginate screens. The screens were then inserted in a photochamber saturated at 100% relative humidity and subjected to a photoperiod of 16 h in the light and 8 h in the dark, with an illumination of 150 muE m(-2) s(-1) provided by fluorescent lamps. After 48 h of nutrient starvation, the immobilized cells were used for the removal of ammonium and orthophosphate from a synthetic secondary wastewater effluent in a plexiglass reactor. During the sequential operation of starvation followed by incubation in the presence of nutrients, fast growth of viable cells in the gel matrix was obtained and there was no appreciable decay of chlorophyll a or cell activity. When these immobilized and starved cells were incubated in wastewater, ammonium (NH(4) (+)) and orthophosphate (PO(4) (3-)) ions were quickly taken up from medium. After three successive 2-h exposures to wastewater, immobilized algal cells were freed by dissolving the Ca-alginate with phosphate as 0.2 M Na(3)PO(4) and resuspended in fresh culture medium. Results indicate that free cells transferred to rich medium remained viable, but the growth rate revealed that the viable cells decreased their culturability. (c) 1995 John Wiley & Sons, Inc.