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In a single bout maximal effort isometric forearm handgrip exercise test (maximal effort exercise test, MXT), contraction impulse exhibits exponential decay to an asymptote equivalent to critical impulse (CI). It is unknown whether oxygen delivery (O2del) and consumption ([Formula: see text]) achieved at CI are maximal. Healthy men participated in a randomized crossover trial at Queen’s University (Kingston, ON) between October 2017–May 2018. Participants completed an MXT and forearm incremental exercise test to limit of tolerance (IET-LOT) (7 completed MXT followed by IET-LOT vs. 4 completed IET-LOT followed by MXT) within a 2 week period. Data are presented as mean ± standard deviation. Maximal forearm blood flow (FBF) and O2del were not different in 11 men (21 ± 2.5 years) between MXT and IET-LOT (FBF = 473.8 ± 132.2 mL/min vs. 502.3 ± 152.3 mL/min; P = 0.482, ηp2 = 0.015; O2del = 85.2 ± 23.5 mL/min vs. 92.2 ± 37.0 mL/min; P = 0.456, ηp2 = 0.012). However, MXT resulted in greater maximal [Formula: see text] than IET-LOT (44.5 ± 15.2 mL/min > 36.8 ± 11.4 mL/min; P = 0.007, ηp2 = 0.09), due to greater oxygen extraction (54.0 ± 10.0% > 44.4 ± 8.6%; P = 0.021, ηp2 = 0.185). As CI was 88.6 ± 8.2% of IET-LOT contraction impulse, maximal O2 cost of contractions in MXT was greater than IET-LOT (0.45 ± 0.14 mL/min/Ns > 0.33 ± 0.09 mL/min/Ns; P p2 = 0.166). In healthy men, MXT identifying CI results in similar peak oxygen delivery but greater peak [Formula: see text] via increased extraction compared to an IET-LOT, indicating increased oxygen cost. MXT-CI may better estimate maximal [Formula: see text] than traditional IET-LOT for this exercise modality.

The Polar Radiant Energy in the Far InfraRed Experiment (PREFIRE) mission will measure the Earth’s emission at wavelengths ranging from 3-54 µm. The pre-launch clear-sky retrieval algorithm, evaluated with simulated test data, indicates that PREFIRE measurements will be valuable for retrieving atmospheric water vapor and temperature profiles. Far infrared measurements provide unique retrieval information, indicated by the high ranking of select FIR channels as primary contributors to the total degrees of freedom for signal (DFS). In utilizing all the PREFIRE channels, the average total DFS of 4 test regions ranges from 1.90 - 4.71. The information content increases with higher column water vapor and in the presence of near surface temperature inversions. Using the DFS profiles for guidance, the retrieval concentrates information into 7 distinct layers to reduce the retrieval uncertainty per layer. Sensitivity tests indicate forward model error due to surface emissivity uncertainty results in about a 9% increase in column water vapor uncertainty. The clear-sky retrieval is sensitive to the presence of undetected ice clouds, especially those with optical depths larger than 0.2. Hence, in addition to a separate PREFIRE cloud mask, optimal estimation retrieval metrics are explored as possible indicators of cloudy scenes.

Objective Despite the organ shortage, a significant number of deceased donor kidneys are retrieved but not transplanted (RNTK). This study aims to describe and analyze the main causes of potential grafts discard and to propose adequate solutions. Material and methods We collected data from the Cristal database of the French Biomedicine Agency about RNTK over one year. Expert opinion was taken from urologists with extensive expertise in renal transplantation. They retrospectively analyzed each record to assess the appropriateness of each graft refusal and subsequent kidney discard. Results 252 kidneys were retrieved but not transplanted in France over one year. The main reasons for discard were vascular abnormalities in 43.7% (n=110), suspicion of malignant tumor in 18.7% (n = 47), and severe histological lesions on preimplantation biopsy in 12.3% (n = 31). The reason for kidney refusal was undetermined in 4.8% (n=12). Iatrogenic lesions were responsible for 26.2% (n=66). Overall, 46.0% (n=116) and 25.0% (n=63) of the grafts were respectively properly and improperly denied, and the analysis was not possible in 29.0% (n=73). In total, 36.9% of RNTK could have been transplanted. Conclusion Reduction of iatrogenic lesions, improvement of microsurgical repair skills and proper histological examination are necessary to reduce the number of RNTK. A prospective study applying the proposed principles is undoubtedly essential to complete this work.

The performance of a CMOS transmitter designed for planetary science in situ molecular sensing applications having an operational bandwidth of 180–190 GHz and peak output power of 0.6 mW (−2.22 dBm) is evaluated with a series of spectroscopic-based experimental trials. Continuous wave frequency modulated absorption schemes are exploited to probe the Doppler and sub-Doppler lineshape profiles of the water rotational transition at 183.310 GHz. These results demonstrate the tuning finesse and phase-noise characteristics of the integrated circuit embedded phase lock loop used to generate coherent mm-wave radiation are sufficient for high-precision molecular spectroscopy applications. A description of the pulse modulator designed into the CMOS circuitry allowing for implementation of sensitive emission-based Fourier transform detection schemes is provided with performance characterized for spectroscopically relevant pulse durations (40–500 ns). Results are accompanied by a spectral analysis of the transmitter pulse signal leakage, where the total isolation is measured to be 22 dB. The first emission-based molecular detections obtained with this source are presented demonstrating viability for this transmitter to be incorporated into future planned resonant cavity enhanced in situ molecular sensing systems.

Resume L’histoire des premieres transplantations est un modele ideal pour analyser les differentes etapes de l’innovation de rupture en chirurgie. Les pionniers empruntent souvent des chemins semes d’embuches, d’erreurs ou d’echecs. Parfois, la victoire est la, brillante ou plus modeste. Nous proposons de reexplorer ces voies extraordinaires qui ont conduit aux premieres transplantations du rein, du foie, du poumon et du cœur. La premiere transplantation devient un jour possible pour plusieurs raisons : des travaux ont ete realises au laboratoire, permettant a la technique chirurgicale d’etre au point ; le contexte legislatif et societal est favorable et surtout des pionniers vont oser l’application humaine. L’echec initial ne sera pas technique mais immunologique. Tout ne sera pas parfait, en particulier au niveau ethique dans certains cas. Par ailleurs, les evenements inciteront souvent a une grande humilite. Meme si les contextes historiques et legislatifs ont considerablement change de meme que la science, la societe et l’organisation du systeme de sante, cette analyse est riche d’enseignements pour le chirurgien qui souhaite, aujourd’hui, s’engager dans la voie de l’innovation face a un probleme encore non resolu. Car rien n’est jamais ecrit en ce domaine.

Summary The history of the first transplants is an ideal model for analyzing the different stages of disruptive innovation in surgery. Pioneers have often taken paths that were strewn with pitfalls, mistakes or failures. Sometimes victory, brilliant or more modest, lies at the end of this path. We propose to re-explore the extraordinary pathways that led to the first transplantations of the kidney, liver, lung and heart. That these first transplants should one day become possible required the concurrence of several factors: basic research, laboratory work to perfect the surgical techniques, a favorable legislative and societal context, and, above all, pioneering surgeons who would dare to apply their expertise to human subjects. Initial failures were not technical but immunological. Not everything would be perfect, especially ethical questions in some cases. Furthermore, initial results often humbled the greatest surgeons. Even though the historical and legislative contexts have evolved considerably as have science, society and the organization of the health system, this analysis of the past is rich in lessons for the modern surgeon who wishes to embark today along innovative pathways in the face of a still unresolved problem. Because nothing is ever carved in stone.

A low anti-spike antibody response of 28.6% was observed 28 days after BNT162b2 vaccine second dose among 133 solid organ transplant recipients without previous coronavirus disease 2019 (COVID-19). No serious adverse events were recorded. Four severe COVID-19 cases were reported between or after the 2 doses. Our data suggest to change the vaccine strategy.

Spectroscopic measurements in the millimeter, submillimeter, or THz range, with resolutions exceeding a MHz, provide for highly specific detections of gas-phase absorption and emission by atoms and molecules. Due to relatively low excitation energies involved in the transitions, multiple features are observable in most physical systems, and thus such observations dominate the scientific discovery of molecules in space and contribute significantly to remote sensing of the Earth and planetary bodies. The methods and techniques of THz spectroscopy continue to evolve as capabilities and technologies expand. In this article, we review the genesis of THz spectroscopy in both the laboratory and in space, and follow its development to date, providing background on the challenges, and context for the current developments that promise to extend both remote and in-situ gas composition sensing.

The Polar Radiant Energy in the Far Infrared Experiment (PREFIRE) mission will, for the first time, systematically document the far-infrared (15–54 µm) spectral region from space. The environmental sampling characteristics of the PREFIRE CubeSats, defined in terms of surface temperature (Tsfc) and column water vapor (CWV) are evaluated for a range of possible orbit scenarios for both clear-sky and all-sky conditions over a variety of surface types (land, ocean, sea ice, snow, glacier ice) at both poles. Using NASA Aqua’s Atmospheric Infrared Sounder (AIRS) and Advanced Microwave Sounding Unit (AMSU) retrievals to define the climatological ranges of Tsfc and CWV, the fraction of environmental regimes observed by distinct PREFIRE configurations are evaluated. The sampling rates within any single year for two-orbit CubeSat launches spanning both polar regions are ~75% for clear-sky and ~85% for all-sky compared to the AIRS/AMSU climatology. Decreasing mission duration from 12 to 3 months decreases sampling much more (10%–20%) than decreasing the swath width from 15 to 8 footprints (6%–9%). For a single CubeSat launch, a 98° orbital inclination provides slightly better sampling than either 93° or 103°. For a two-orbit CubeSat launch, a combination of 93° + 98° is somewhat preferable to 103° + 98°. Finally, a 50% data loss rate simulated by dropping out every other orbit leads to only a modest 7%–8% reduction in sampling from full data coverage. This statistical analysis demonstrates that low-cost platforms could offer similar coverage as present-day flagship missions for sampling wide-ranging Tsfc and CWV states over polar regions.

This study tested the hypothesis that a novel, gravity-induced blood flow restricted (BFR) aerobic exercise (AE) model will result in greater activation of the AMPK–PGC-1α pathway compared with work rate-matched non-BFR. Thirteen healthy males (age: 22.4 ± 3.0 years; peak oxygen uptake: 42.4 ± 7.3 mL/(kg·min)) completed two 30-min work rate-matched bouts of cycling performed with their legs below (CTL) and above their heart (BFR) at ∼2 weeks apart. Muscle biopsies were taken before, immediately, and 3 h after exercise. Blood was drawn before and immediately after exercise. Our novel gravity-induced BFR model led to less muscle oxygenation during BFR compared with CTL (O2Hb: p = 0.01; HHb: p < 0.01) and no difference in muscle activation (p = 0.53). Plasma epinephrine increased following both BFR and CTL (p < 0.01); however, only norepinephrine increased more following BFR (p < 0.01). PGC-1α messenger RNA (mRNA) increased more following BFR (∼6-fold) compared with CTL (∼4-fold; p = 0.036). VEGFA mRNA increased (p < 0.01) similarly following BFR and CTL (p = 0.21), and HIF-1α mRNA did not increase following either condition (p = 0.21). Phosphorylated acetyl-coenzyme A carboxylase (ACC) increased more following BFR (p < 0.035) whereas p-PKA substrates, p-p38 MAPK, and acetyl-p53 increased (p < 0.05) similarly following both conditions (p > 0.05). In conclusion, gravity-induced BFR is a viable BFR model that demonstrated an important role of AMPK signalling on augmenting PGC-1α mRNA. Novelty Gravity-induced BFR AE reduced muscle oxygenation without impacting muscle activation, advancing gravity-induced BFR as a simple, inexpensive BFR model. Gravity-induced BFR increased PGC-1α mRNA and ACC phosphorylation more than work rate-matched non-BFR AE. This is the first BFR AE study to concurrently measure blood catecholamines, muscle activation, and muscle oxygenation.

Recently, percutaneous microbiopsy needles have been used as a less invasive alternative to the Bergstrom needle for obtaining human skeletal muscle biopsy to assess changes in protein content, gene expression, and enzymatic activities. Unlike the Bergstrom muscle biopsy procedure, potential complications associated with microbiopsies of human skeletal muscle have not been documented. Therefore, the present case report follows a young male's recovery from a muscle biopsy‐induced hemorrhage/hematoma of the right vastus lateralis with the specific aims of (1) informing future participants, researchers, and clinicians on expected time course of recovery and (2) informing methods to minimize future participant adverse event risk during and after the percutaneous microbiopsy procedure. The present case report demonstrates that the inadvertent hemorrhaging of a neighboring vessel by percutaneous microbiopsy procedure can be debilitating. To minimize the risk of muscle biopsy‐induced hemorrhage/hematoma, we advise post‐biopsy compression for up to 15 min and post‐biopsy follow‐up should be completed for up to 72 h. When there is indication of hematoma development, compression should be applied, and the participant should avoid exercise and physical activity., The present case report demonstrates that the inadvertent hemorrhaging of a neighboring vessel by percutaneous microbiopsy procedure can be debilitating. To minimize the risk of muscle biopsy‐induced hemorrhage/hematoma, post biopsy compression is recommended for up to 15 min and post biopsy follow‐up should be completed for up to 72 h.

Direct time-domain sampling oscilloscopic capture of ultra-high bandwidth (32–102 GHz) modulated optical waveforms at 1550 nm is demonstrated at optical power levels below −100 dBm. To detect fast optical waveforms directly at power levels far below what traditional optical oscilloscope methods can measure, we use a time-correlated single-photon counting (TCSPC) sampling acquisition method, recently developed integrated electro-optic devices with >100 GHz electro-optic bandwidth, and single photon detectors with < 5 ps jitter. We show the reconstruction of the time domain signals by collecting histograms of time-binned single photons captured using TCSPC and characterize the spectral components in the frequency domain. The ability to acquire ultra-weak eye diagrams and identify high-frequency spectral components from a relatively small ensemble of single-photon measurements may lead to significant advances in optical waveform capture technology.

The collision-induced absorption (CIA) spectra of oxygen and dry air have been measured in the near-infrared and visible regions, covering the O2(B) band at 687 nm and double transitions in the 630 nm and 577 nm regions. A custom-design 1 m path length high-pressure cell was developed and configured to a Bruker 125HR Fourier transform spectrometer at the Jet Propulsion Laboratory. A super-luminous Laser Driven Light Source (LDLS) was also used to improve the photon flux incident upon the spectrometer. A series of spectra of pure O2 and dry air were obtained at various high pressures up to 131 bars at room temperature. For the measurement of O2–O2 CIA in the B band region, the monomer resonance absorption contribution has been subtracted from the observed spectra by simulating the O2(B) band absorption with a speed-dependent Voigt line shape profile with line mixing effects taken into account. The remaining absorption component was regarded as the CIA in the region. The integrated absorption coefficient was measured to be 3.2(6) × 10−6 cm−2/Amagat2 for the O2(B) band region, which is significantly lower than literature values. For the two double transition bands in the 630 and 577 nm regions, the integrated CIA bands from the present work were measured to be 2.50(14) and 3.26(18) × 10−4 cm−2/Amagat2, respectively. The present measurements are significantly higher than prior measurements for the 630 nm band region, while they are slightly lower than prior measurements for the 577 nm band region. For dry air, the integrated CIA bands were measured to be 0.10(2) and 0.15(2) × 10−4 cm−2/Amagat2, respectively, for the 630 and 577 nm regions, no appreciable contribution from O2–N2 pairs was observed. The results are compiled in electronic supplements.

A complete 183-GHz CMOS/Indium Phosphide (InP) hybrid heterodyne-spectrometer is realized for spaceborne atmospheric remote sensing applications. It captures spontaneous emission from thermally populated pure rotational states for investigating Earth/planetary atmosphere and interstellar media. Recent missions such as the heterodyne instrument for far-infrared, the microwave limb sounder, and the microwave instrument for Rosetta orbiter highlighted the wealth of scientific knowledge that can be attained by utilizing heterodyne-spectrometers. However, major challenges still remain in mission cost, instrument size, weight, and power (SWaP). Highly integrated CMOS circuits are designed to prototype a low-cost/SWaP spectrometer system and conduct challenging science missions. Within the prototype system, a 183-GHz receiver with a frequency synthesizer is designed in the 28-nm CMOS, and a back-end 6-GS/s 4096-point spectrometer processor is designed in the 65-nm CMOS. The receiver's center frequency is tunable from 180 to 200 GHz. An external InP low-noise amplifier is added at the front-end to provide the required receiver sensitivity. The demonstrated 28-nm CMOS receiver and 65-nm CMOS spectrometer consume 515 mW under 1.5/1.15-V and 1500 mW under 1 V supply, respectively. The complete system achieves 700 to 1000 K noise temperature within the interested bandwidth and RMS uncertainty improvement up to 10 s integration according to the Allan deviation measurements. The spectrometer's capability in detecting gas phase molecular compounds is verified with laboratory trials employing water (H2O) and methyl-cyanide (CH3CN).

Perceived fatigability, which has perception of physical strain and of mental strain as its components, can impact exercise tolerance. Upon ascent to high altitude, low landers experience reduced exercise capacity and reduced tolerance for a given absolute submaximal work rate. It is established that perceived physical strain tracks with relative exercise intensity. However, it is not known how altitude ascent affects perceived mental strain relative to perceived physical strain. We tested the hypothesis that when exercising at the same relative exercise intensity perceived physical strain will remain unchanged whereas perceived mental strain will decrease on ascent from low to high altitude in the Everest region in Nepal. Twelve hours after arriving at each of three elevations; 1400 m, 3440 m, and 4240 m, 12 untrained participants used the task effort awareness (TEA) and physical‐rating of perceived exertion (P‐RPE) scales to report perceived mental and physical strain during a 20 min walking test at a self‐monitored heart rate reserve (HRR) range of 40–60% (Polar HR Monitor). TEA and P‐RPE were recorded twice during exercise (5–7 min and 14–16 min). Neither P‐RPE (1400 m: 11.1 ± 1.8, 3440 m: 10.7 ± 1.2, 4240 m: 11.5 ± 1.5) nor %HRR (1400 m: 55.25 ± 7.34, 3440 m: 51.70 ± 6.70, 4240 m: 50.17 ± 4.02) changed as altitude increased. TEA decreased at 4240 m (2.05 ± 0.71) compared to 1400 m (3.44 ± 0.84)––this change was not correlated with any change in %HRR nor was it due to a change in core affect. These findings support our hypothesis and demonstrate the independence of perceived physical and perceived mental strain components of perceived fatigability. Implications for exercise tolerance remain to be determined., Until now, no work had examined the domain of perceived mental strain upon ascent from low to high altitude. We tested and confirmed the hypothesis that at the same relative submaximal exercise intensity, participants would perceive the same amount of physical strain but less mental strain upon ascent from low to high altitude. Therefore, perceived mental strain dissociates from perceived physical strain upon ascent from low to high altitude—the mechanism(s) responsible for this dissociation remain to be determined.