Maximal Intensity Research Articles

A Random Forest clustering to explore the influence of physical fitness level of youth basketball players on match-related physical performance

This study aimed to analyse the influence of different physical fitness levels of youth basketball players on match-related physical performance, using Random Forest clustering to distinguish between high-fitness level players and low-fitness level players. Twenty male youth basketball players completed the following physical performance tests in two separate sessions: bilateral and unilateral countermovement jumps, bilateral and unilateral horizontal jumps, single leg lateral jumps, the 20 m linear straight sprint test, the 505 test and a repeated sprint ability test. 1 week after the second testing day, players completed a simulated match while external loads were monitored using an ultra-wide band-based Local Positioning System. A Random Forest clustering was used to create two different clusters composed of players with similar physical fitness attributes (high- and low-fitness level players). Results indicate that the Random Forest clustering adequately discriminated among the players in different groups according to their physical fitness attributes. High-fitness level players covered more distance per min in all intensity thresholds and reached higher maximal speed and acceleration intensity during the simulated matches ( p < 0.05). These results may assist basketball practitioners in understanding running performance variations during matches and can be used to optimise preparation for individual players.

Self-powered optical ion sensor array based on potentiometric probes coupled to electronic paper

This work describes a direct optical readout of an ion-selective potentiometric sensing array without an external power supply. Electronic paper (e-paper) was chosen as the signal transducer owing to its fast response on the order of seconds and its wide dynamic range of about 1.5 V. The capacitive character of the display allows one to observe the optical response at zero current, which is a desired condition for the potentiometric measurement. An applied potential of 1 V gives a transient charge flow of about 11 μC for the e-paper to exhibit a maximal intensity change. The cathodes of three different pixels of the e-paper were connected to three different ISEs responsive to Na+, K+, and Ca2+, while their common anode was connected to the shared reference electrode (RE). In this manner, each pixel is mapped to the behavior of one sensor, making it possible to detect multiple ions with an e-pixel array. The sensor configuration gave quantitative information on Na+, K+, and Ca2+ from 10−5 M to 10−1 M by analyzing the RGB information of the pixels. The e-paper exhibited a stable response within half a minute, much faster than previously established electrochromic material transducers such as Prussian Blue (PB). With this approach we successfully carried out multi-ion concentration sensing without external power, which is potentially attractive for applications in environmental monitoring, clinical assays and wearable sensing devices.

Sprint Interval Training on Stationary Air Bike Elicits Cardiorespiratory Adaptations While Being Time-Efficient.

Moghaddam, M, Cervantes, M, Cheshier, B, and Jacobson, BH. Sprint interval training on stationary air bike elicits cardiorespiratory adaptations while being time-efficient. J Strength Cond Res 37(9): 1795-1801, 2023-Sprint interval training (SIT) refers to a set of brief intermittent exercises that are performed at maximal intensity. This study compared the effects of 2 SIT protocols (e.g., 10-5-SIT and 20-10-SIT) vs. moderate-intensity continuous training (MICT) on cardiovascular adaptations, using stationary air bikes. Thirty-two recreationally active individuals were randomly assigned to the 3 performance groups, such as 10-5-SIT (n = 11), 20-10-SIT (n = 10), and MICT (n = 11), to train 3 days per week for 4 weeks. Moderate-intensity continuous training included 30 minutes of cycling at 75% of maximal heart rate reserve, whereas the SIT protocols consisted of 3 sets of 8 intervals at all-out intensity. The 10-5-SIT and 20-10-SIT were performed with 10-second work:5-second rest and 20-second work:10-second rest, with 2.5- and 5-minute recovery periods between sets, respectively. A ramp protocol was used before and after the intervention via cycle ergometer to assess aerobic performance. Time to exhaustion (TTE), absolute V̇o2max (A-V̇o2max), relative V̇o2max (R-V̇o2max), and metabolic equivalents (METs) were measured and analyzed with 2-way mixed factorial analyses of variance (ANOVAs). In addition, total work (TW) during 12 sessions were recorded and analyzed with 1-way ANOVA. Significant (p < 0.05) differences were found for TW (10-5-SIT: 907.3 ± 332.0, 20-10-SIT: 1230.0 ± 188.1, and MICT: 2263.0 ± 896.9 calories) between groups. A significant main effect of time was observed for 10-5-SIT, 20-10-SIT, and MICT (p < 0.05) in TTE (increased by 7.3, 8.7, and 8.2%), A-V̇o2max (increased by 13.0, 11.8, and 13.6%), R-V̇o2max (increased by 12.6, 12.1, and 14.8%), and METs (increased by 12.7, 12.3, and 14.9%), respectively. Despite less volume and duration, both SIT protocols induced cardiorespiratory adaptations similar to MICT. These findings suggest that performing SIT on a stationary air bike is valuable because of time-efficiency and cardiorespiratory adaptations.

Devising a framework of optogenetic coding in the auditory pathway: Insights from auditory midbrain recordings

Cochlear implants (CIs) restore activity in the deafened auditory system via electrical stimulation of the auditory nerve. As the spread of electric current in biological tissues is rather broad, the spectral information provided by electrical CIs is limited. Optogenetic stimulation of the auditory nerve has been suggested for artificial sound coding with improved spectral selectivity, as light can be conveniently confined in space. Yet, the foundations for optogenetic sound coding strategies remain to be established. Here, we parametrized stimulus-response-relationships of the auditory pathway in gerbils for optogenetic stimulation. Upon activation of the auditory pathway by waveguide-based optogenetic stimulation of the spiral ganglion, we recorded neuronal activity of the auditory midbrain, in which neural representations of spectral, temporal, and intensity information can be found. Screening a wide range of optical stimuli and taking the properties of optical CI emitters into account, we aimed to optimize stimulus paradigms for potent and energy-efficient activation of the auditory pathway. We report that efficient optogenetic coding builds on neural integration of millisecond stimuli built from microsecond light pulses, which optimally accommodate power-efficient laser diode operation. Moreover, we performed an activity-level-dependent comparison of optogenetic and acoustic stimulation in order to estimate the dynamic range and the maximal stimulation intensity amenable to single channel optogenetic sound encoding, and indicate that it complies well with speech comprehension in a typical conversation (65 dB). Our results provide a first framework for the development of coding strategies for future optogenetic hearing restoration.

Effects of water immersion and pre-oxidation on re-ignition characteristics of non-caking coal

Coal spontaneous combustion (CSC) in waterlogged goafs has become an essential threat to coal mine safety production, so it is necessary to comprehensively and deeply evaluate the re-ignition characteristics of residual coal after water immersion and pre-oxidation. The re-ignition process of non-caking coal under the influence of water immersion and pre-oxidation was tested using a temperature-programmed test system (TPTS), and the spontaneous combustion characteristic parameters and limit characteristic parameters of low-temperature oxidation were calculated. The results show that the spontaneous combustion characteristic parameters such as CO production rate, oxygen consumption rate, and heat release intensity positively correlate with temperature. The minimum float coal thickness and lower limit oxygen concentration show a trend of increasing and then decreasing with the temperature increase, while the maximal air leakage intensity is the opposite. In addition, the expansion of pores and cracks caused by water immersion and pre-oxidation processes and the increase of unstable functional groups promote the oxygen consumption and heat generation of immersed and oxidized coal, which reduces the characteristic temperature, and activation energy, and limit characteristic parameters. Meanwhile, water immersion and pre-oxidation can synergistically accelerate the low-temperature oxidation process of non-caking coal, which significantly increases the CSC risk of coal O140I30 and coal O90I30. The results enrich the research on the characteristics of water immersed and oxidation coals re-ignition, which may be applied to prevent CSC in the future.

Respiratory signal estimation for cardiac perfusion SPECT using deep learning.

Respiratory motion induces artifacts in reconstructed cardiac perfusion SPECT images. Correction for respiratory motion often relies on a respiratory signal describing the heart displacements during breathing. However, using external tracking devices to estimate respiratory signals can add cost and operational complications in a clinical setting. We aim to develop a deep learning (DL) approach that uses only SPECT projection data for respiratory signal estimation. A modified U-Net was implemented that takes temporally finely sampled SPECT sub-projection data (100ms) as input. These sub-projections are obtained by reframing the 20-s list-mode data, resulting in 200 sub-projections, at each projection angle for each SPECT camera head. The network outputs a 200-time-point motion signal for each projection angle, which was later aggregated over all angles to give a full respiratory signal. The target signal for DL model training was from an external stereo-camera visual tracking system (VTS). In addition to comparing DL and VTS, we also included a data-driven approach based on the center-of-mass (CoM) strategy. This CoM method estimates respiratory signals by monitoring the axial changes of CoM for counts in the heart region of the sub-projections. We utilized 900 subjects with stress cardiac perfusion SPECT studies, with 302 subjects for testing and the remaining 598 subjects for training and validation. The Pearson's correlation coefficient between the DL respiratory signal and the reference VTS signal was 0.90, compared to 0.70 between the CoM signal and the reference. For respiratory motion correction on SPECT images, all VTS, DL, and CoM approaches partially de-blured the heart wall, resulting in a thinner wall thickness and increased recovered maximal image intensity within the wall, with VTS reducing blurring the most followed by the DL approach. Uptake quantification for the combined anterior and inferior segments of polar maps showed a mean absolute difference from the reference VTS of 1.7% for the DL method for patients with motion >12mm, compared to 2.6% for the CoM method and 8.5% for no correction. We demonstrate the capability of a DL approach to estimate respiratory signal from SPECT projection data for cardiac perfusion imaging. Our results show that the DL based respiratory motion correction reduces artefacts and achieves similar regional quantification to that obtained using the stereo-camera VTS signals. This may enable fully automatic data-driven respiratory motion correction without relying on external motion tracking devices.

Temporal perception is distorted by submaximal and maximal isometric contractions of the knee extensors in young healthy males and females.

The estimate of time (temporal perception) is important for activities of daily living, sports and even survival, however time perception research needs greater scrutiny. Time estimation can influence movement decisions and determine whether the individual is successful at their goal, The objectives of this study were to examine participants perception of time at 5-, 10-, 20-, and 30-s intervals to determine possible distortions of time estimates caused by varying intensity isometric contractions, and sex differences. In this repeated measures study, 19 participants (10 females, 9 males) endured two sessions, which consisted of a cognitive task of estimating time intervals while performing an isometric knee extension at maximal, submaximal (60%), and distraction (10%) intensities and a non-active control. In addition to time estimates; heart rate (HR), tympanic temperatures and electromyography during the intervention contractions were monitored. Maximal contractions induced significantly greater time underestimations at 5-s (4.43 ± 0.93, p = 0.004), 20-s (18.59 ± 2.61-s, p = 0.03), and 30-s (27.41 ± 4.07-s, p = 0.004) than control. Submaximal contractions contributed to time underestimation at 30-s (27.38 ± 3.17-s, p = 0.001). Females demonstrated a greater underestimation of 5-s during the interventions than males (p = 0.02) with 60% submaximal (-0.64-s ± 0.26) and distraction (-0.53-s ± 0.22) conditions. For the other 10-, 20-, 30-s intervals, there was no significant time perception sex differences. The control condition exhibited lower HR (75.3 ± 11.6) than the maximal (92.5 ± 13.9), 60% submaximal (92.2 ± 14.4) or distraction (90.5 ± 14.7) conditions. Tympanic temperatures were not influenced by the contraction intensities. There was greater integrated knee extensor electromyographic activity during the maximal contractions to suggest greater neuromuscular activation that may influence time perception. However, there was no consistent effect of changes in HR or temperature on time estimates. This work adds to the growing literature of time perception during exercise to state that time is significantly underestimated when performing moderate to vigorous intensity exercise.

Diagnostic value of serum CA125 combined with PET/CT in ovarian cancer and tuberculous peritonitis in female patients.

To evaluate the diagnostic value of serum CA125 combined with 18F-FDG PET/CT in ovarian cancer (OC) and tuberculous peritonitis (TBP) in female patients and to establish a diagnostic scoring system. A total of 86 female patients (64 OC and 22 TBP) were included in this study. Serum CA125, PET/CT maximal intensity projection (MIP), maximal standardized uptake value, ovarian mass, ascites volume, and other indicators were analyzed and a diagnostic scoring system was established according to the weights of statistically significant indicators. Univariate analysis showed that serum CA125 in OC and TBP patients were 2079.9 ± 1651.3 U/mL and 448.3 ± 349.5 U/mL (P < 0.001). In MIP images, abdominal lesions were focal distribution in 92.2% (59/64) of OC patients and diffuse distribution in 95.5% (21/22) of TBP patients (P<0.001). Ovarian masses could be observed in 82.8% (53/64) OC patients and 31.8% (7/22) TBP patients (P <0.001). The other indicators were not statistically significant. Logistic regression analysis showed that serum CA125 and MIP were independent risk factors for diagnosis. A diagnostic scoring system could be established based on serum CA125, MIP and ovarian mass, and the diagnostic sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 98.4% (63/64), 95.5% (21/22), 97.7% (84/86), 98.4% (63/64), and 95.5% (21/22), respectively. Serum CA125 combined with PET/CT is of great value in the diagnosis of OC and TBP. A simple and efficient diagnostic scoring system can be established using serum CA125, MIP image feature, and ovarian mass.

Hydrothermal synthesis and ionic sensing properties of graphitic carbon nitride quantum dots

BackgroundThis work adopts an efficient method including thermal calcination, surface hydroxylation, and hydrothermal cutting to synthesize graphitic C3N4 quantum dots (CNQDs) for detecting metal ions in aqueous solutions. MethodsFunctionalized CNQDs, ranged from 2 to 6 nm in particle size, were of layered crystalline and contain a large amount of surface functionalities such as carbonyl, carboxylic, and amino groups. The CNQD suspension exhibited a maximal fluorescence intensity at 420 nm with high quantum yield of 13.6% under UV irradiation. Significant findingsThe CNQD suspension demonstrated superior sensitivity and selectivity toward iron ions with ppm-level detection limit in liquid phase. The Stern-Volmer analysis revealed that CNQD suspension was appropriate for the detection of Fe3+ and Fe2+ ions with LOD of 6.5 and 7.7 ppm, respectively. The fluorescence quenching mechanism of CNQD suspension mainly originates from a strong interaction between the ions and the surface functionalities followed by the photoinduced energy transfer effect, thus inducing the fluorescence extraction. Moreover, the CNQD suspension also offers a satisfactory biocompatibility toward 3T3 cell after 24 h. Accordingly, the robust design of CNQDs developed in this work paves the way for developing highly sensitive and selective probes for detecting target species in aqueous solutions.

The utility of arterial spin labelled perfusion-weighted magnetic resonance imaging in measuring the vascularity of high grade gliomas – A prospective study

BackgroundDynamic susceptibility contrast (DSC) perfusion weighted imaging (PWI) currently remains the gold standard technique for measuring cerebral perfusion in glioma diagnosis and surveillance. Arterial spin labelling (ASL) PWI is a non-invasive alternative that does not require gadolinium contrast administration, although it is yet to be applied in widespread clinical practice. This study aims to assess the utility of measuring signal intensity in ASL PWI in predicting glioma vascularity by measuring maximal tumour signal intensity in patients based on pre-operative imaging and comparing this to maximal vessel density on histopathology. MethodsPseudocontinuous ASL (pCASL) and DSC images were acquired pre-operatively in 21 patients with high grade gliomas. The maximal signal intensity within the gliomas over a region of interest of 100 mm2 was measured and also normalised to the contralateral cerebral cortex (nTBF-C), and cerebellum (nTBF-Cb). Maximal vessel density per 1 mm2 was determined on histopathology using CD31 and CD34 immunostaining on all participants. ResultsUsing ASL, statistically significant correlation was observed between maximal signal intensity (p < 0.05) and nTBF-C (p < 0.05) to maximal vessel density based on histopathology. Although a positive trend was also observed nTBF-Cb, this did not reach statistical significance. Using DSC, no statistically significant correlation was found between signal intensity, nTBF-C and nTBF-Cb. There was no correlation between maximal signal intensity between ASL and DSC. Average vessel density did not correlate with age, sex, previous treatment, or IDH status. ConclusionsASL PWI imaging is a reliable marker of evaluating the vascularity of high grade gliomas and may be used as an adjunct to DSC PWI.

Do poles really "save the legs" during uphill pole walking at different intensities?

In sky- and trail-running competitions, many athletes use poles. The aims of this study were to investigate whether the use of poles affects the force exerted on the ground at the feet (Ffoot), cardiorespiratory variables and maximal performance during uphill walking. Fifteen male trail runners completed four testing sessions on different days. On the first two days, they performed two incremental uphill treadmill walking tests to exhaustion with (PWincr) and without poles (Wincr). On the following days, they performed submaximal and maximal tests with (PW80 and PWmax) and without (W80 and Wmax) poles on an outdoor trail course. We measured cardiorespiratory parameters, the rating of perceived exertion, the axial poling force and Ffoot. When walking on the treadmill, we found that poles reduced maximum Ffoot (- 2.8 ± 6.4%, p = 0.03) and average Ffoot (- 2.4 ± 3.3%, p = 0.0089). However, when outdoors, we found pole effect only for average Ffoot (p = 0.0051), which was lower when walking with poles (- 2.6 ± 3.9%, p = 0.0306 during submaximal trial and - 5.21 ± 5.51%, p = 0.0096 during maximal trial). We found no effects of poles on cardiorespiratory parameters across all tested conditions. Performance was faster in PWmax than in Wmax (+ 2.5 ± 3.4%, p = 0.025). The use of poles reduces the foot force both on the treadmill and outdoors at submaximal and maximal intensities. It is, therefore, reasonable to conclude that the use of poles "saves the legs" during uphill without affecting the metabolic cost.

Virtual Reality Hypnoanxiolysis and Analgesia for Emergency Department Needle-Related Procedures: A Prospective Interventional Cohort Pilot Study Implementation

We hypothesized that virtual reality–delivered hypnotherapy reduces anxiety (hypnoanxiolysis) and pain (hypnoanalgesia) related to needle procedures. Our primary objective was to assess whether this would result in lower procedural anxiety and/or pain scores from baseline for pediatric patients undergoing nonemergent needle-related procedures. A prospective interventional pilot study of a cohort of 22 patients (aged 8-15 years) who required a needle procedure in the emergency department was conducted, and parents (dyad) were consented. Anxiety and pain measurements were taken before and after the intervention for each dyad. The worst anxiety reflected the maximal anxiety intensity experienced by the participant during the procedure using the Visual Analog Anxiety Scale and, similarly for pain, using the validated pediatric Color Analog Pain Scale. Patients, parents, and physicians completed satisfaction scores. Most of the participants reported a reduction in anxiety during the procedure. The participants’ median maximum procedural pain scores were slightly increased from baseline. Eleven (50%) children and 19 physician and parent reports (85%) stated that the needle intervention was easy or very easy. We described novel implementation of virtual reality hypnotherapy in an emergency setting and achieved anxiety reduction for needle-related procedures in a pediatric cohort.

Assessing the controlling factors on watershed soil erosion during intense rainstorm events using radar rainfall and process-based modeling

The evaluation of erosion risk in dry areas is challenging because erosion is often an outcome of individual rainstorms and is highly dependent on rainfall spatiotemporal patterns and on local land-use and topography. This study integrates a hybrid erosion model with rainfall data from high-resolution weather radar to simulate soil erosion during 22 high-intensity flash-flood generating rainstorms in a Mediterranean watershed (69 km2). We examine erosion over individual hillslopes and their spatial average over the watershed, representing intra-watershed and watershed-scale erosion, respectively. Our objectives are to: (a) determine how intra-watershed erosion corresponds to various physiographic factors (rainfall, land-use, topography); (b) determine which of these factors contributes to intra-watershed erosion the most; (c) quantify the effect of temporal variations in rainfall intensities on storm-scale erosion in relation to land-use type. We use for the first time a hybrid erosion model (K2-RHEM-DWEPP) based on the watershed-scale KINEROS2 model, that integrates the hillslope-scale Dynamic WEPP (DWEPP) and RHEM models, which were individually developed to represent erosion processes in croplands and rangelands, respectively. Watershed-scale storm erosion is best correlated with spatially-averaged 10-minutes maximum intensities (R2 = 0.58), and the correlation decreases for longer durations (R2 ≤ 0.54). When the spatially-averaged 10-minutes maximum intensity is multiplied by the area that contributes sediment, a better correlation with watershed-scale erosion is observed (R2 = 0.75). Hillslope erosion rates are higher when both rainfall intensities and topographic slopes are high, while land-use has a second-order effect. Higher storms maximal intensities result in higher hillslope erosion rates, especially over croplands.Our conclusions are useful to target locations for conservation practices and to better understand the effects of climate change on soil erosion.

The Role of 68 Ga-FAPI PET/CT in Breast Cancer Response Assessment and Follow-Up.

68 Ga-fibroblast activation protein inhibitor (FAPI), a new PET/CT radiotracer targeting cancer-associated fibroblasts in tumor microenvironment, can detect many types of cancer. We aimed to assess whether it can also be used for response assessment and follow-up. We followed up patients with FAPI-avid invasive lobular breast cancer (ILC) before and after treatment changes and correlated qualitative maximal intensity projection images and quantitative tumor volume with CT results and blood tumor biomarkers. Six consenting ILC breast cancer patients (53 ± 8 years old) underwent a total of 24 scans (baseline for each patient and 2-4 follow-up scans). We found a strong correlation between 68 Ga-FAPI tumor volume and blood biomarkers ( r = 0.7, P < 0.01), but weak correlation between CT and 68 Ga-FAPI maximal intensity projection-based qualitative response assessment. We found a strong correlation between ILC progression and regression (as assessed by blood biomarkers) and 68 Ga-FAPI tumor volume. 68 Ga-FAPI PET/CT could possibly be used for disease response assessment and follow-up.

A Quantitative Approach to Determine Hydrophobe Content of Associating Polyacrylamide Using a Fluorescent Probe.

Hydrophobically associating polymers have found widespread applications in many domains due to their unique rheological behavior, which is primarily dictated by the hydrophobe content. However, the low fraction of hydrophobic monomers in polymers makes this parameter's precise and straightforward measurement difficult. Herein, a variety of hydrophobically associating polyacrylamides (HAPAM) with different alkyl chain lengths (L) and hydrophobic contents ([H]) were prepared by post-modification and accurately characterized by 1H NMR spectroscopy. The maximal fluorescence emission intensity (I) of 8-anilino-1-naphthalenesulfonic acid, which is sensitive to hydrophobic environments, was then detected in those polymer solutions and shown as a ratio to that in the polymer-free solution (I0). It was found that I/I0 for 0.5 wt% HAPAM can be scaled versus CH, which is a variate related to both L and [H], as I/I0 = 1.15 + 1.09 × 108CH3.42, which was also verified to be applicable for hydrophobic associating hydrolyzed polyacrylamide (HHAPAM). This relationship provides a handy method for determining the hydrophobic content of hydrophobically associating polymers, particularly for field applications.

Large Ranking Games with Diffusion Control

We consider a symmetric stochastic differential game where each player can control the diffusion intensity of an individual dynamic state process, and the players whose states at a deterministic finite time horizon are among the best [Formula: see text] of all states receive a fixed prize. Within the mean field limit version of the game, we compute an explicit equilibrium, a threshold strategy that consists of choosing the maximal fluctuation intensity when the state is below a given threshold and the minimal intensity otherwise. We show that for large n, the symmetric n-tuple of the threshold strategy provides an approximate Nash equilibrium of the n-player game. We also derive the rate at which the approximate equilibrium reward and the best-response reward converge to each other, as the number of players n tends to infinity. Finally, we compare the approximate equilibrium for large games with the equilibrium of the two-player case. Funding: Support from the Deutsche Forschungsgemeinschaft [Grant AN 1024/5-1] is acknowledged. The research of N. Kazi-Tani is supported by the Agence Nationale de la Recherche [Grant ANR-21-CE46-0002-03]. The research of C. Zhou is supported by the National Natural Science Foundation of China [Grant 11871364], the Singapore Ministry of Education [Grants A-8000453-00-00, A-0004273-00-00 and A-0004277-00-00] and the MERLION 2020 award [Grant A-0004589-00-00].

Respiratory protective device: One size to fit them all?

When exposed to hazardous or toxic substances, workers may be required to wear respiratory protective devices, selected in accordance with the pollutant, required protection level, individual characteristics, and work conditions. To emphasize the importance of the selection procedure, this study aimed to investigate the effects of the facial dimensions and breathing rate on the fit and the protection efficiency provided by full-face respirators. Manikin total efficiency measurements (mTEs) were then conducted on five head forms of various facial dimensions equipped with nine respirators of different models and sizes. A breathing machine simulating sinusoidal breathing rates was used to represent seven work rates, from rest to maximal intensity. For each experiment, the manikin fit factor (mFF), characterizing the respirator fit on the head form, was measured by a controlled negative pressure method. By varying the head form, respirator, breathing rate, and mFF, a total of 485 values of mTE were measured. Findings indicate that even if the respirator was equipped with a high-efficiency filter, mTE strongly decreases if the respirator does not fit the face of the wearer. In particular, it was highlighted that one given respirator cannot fit all facial dimensions and that the best match between the respirator size and facial dimensions is difficult to predict because respirator sizes are not standardized. Moreover, although the total efficiency of a well-fitted respirator naturally decreases when increasing the breathing rate due to filtration mechanisms, the reduction is more significant if the respirator does not fit well. To consider both the mTE and the breathing resistance, a quality factor value was determined for each tested combination of head form, respirator, and breathing rate. The maximum manikin fit factor mFFmax measured for each combination of head form and respirator was compared to that measured on nine human subjects with similar facial dimensions, providing encouraging results concerning the use of head forms during respirator testing.

Effects of phenylcapsaicin on aerobic capacity and physiological parameters in active young males: a randomized, triple-blinded, placebo-controlled, crossover trial.

Objective: Phenylcapsaicin (PC) is a new capsaicin analog which has exhibited a higher bioavailability. This sudy assessed the effects of a low dose (LD) of 0.625mg and a high dose (HD) of 2.5mg of PC on aerobic capacity, substrate oxidation, energy metabolism and exercise physiological variables in young males. Materials and methods: Seventeen active males (age = 24.7 ± 6.0years) enrolled to this randomized, triple-blinded, placebo-controlled, crossover trial. Participants attended the laboratory on 4 sessions separated by 72-96h. A submaximal exercise test [to determine maximal fat oxidation (MFO) and the intensity at MFO (FATmax)] followed by a maximal incremental test (to determine VO2max) were performed in a preliminary session. The subsequent sessions only differed in the supplement ingested [LD, HD or placebo (PLA)] and consisted of a steady-state test (60min at FATmax) followed by a maximal incremental test. Energy metabolism, substrate oxidation, heart rate, general (gRPE) and quadriceps (RPEquad) rate of perceived exertion, skin temperature and thermal perception were tested. Results: Clavicle thermal perception was lower in HD compared to PLA and LD (p = 0.04) across time. HD reduced maximum heart rate in comparison to PLA and LD (p = 0.03). LD reported higher general RPE (RPEg) values during the steady-state test compared to PLA and HD across time (p = 0.02). HD and LD elicited higher peak of fat oxidation during the steady-state test compared with PLA (p = 0.05). Intra-test analyses revealed significant differences for fat oxidation (FATox) in favor of HD and LD compared to PLA (p = 0.002 and 0.002, respectively), and for carbohydrate oxidation (CHOox) (p = 0.05) and respiratory exchange ratio (RER) (p = 0.03) for PLA. In the incremental test, only general RPE at 60% of the maximal intensity (W) differed favoring HD (p ≤ 0.05). Conclusion: Therefore, PC may contribute to increase aerobic capacity through the improvement of fat oxidation, maximum heart rate and perceptual responses during exercise.

Generation and Manipulation of Airy Breathing Solitons in an Inhomogeneous Medium with Periodic Potential

The propagation characteristics of Airy beams in an inhomogeneous medium with periodic potential are studied theoretically and numerically. The Gross–Pitaevskii equation was solved with periodic potential using the separating variables method, and a breathing soliton solution and the breathing period were obtained. Further, the propagation properties of an Airy beam, and the interaction between two Airy beams while considering the medium parameters and beam parameters were numerically simulated in detail. First, we discuss the influence of the initial medium parameters (modulation intensity P and modulation frequency ω) on the propagation characteristics. Then, we investigate the effect of the initial beam parameters (initial chirp C and position x0) on the propagation characteristics. Lastly, the interaction of two Airy beams with opposite spatial positions for different phase φ, amplitude A, and initial interval x0 is analyzed. The breathing period and central position of the breathing solitons could be controlled by changing the initial medium parameters. By varying the initial beam parameters, the deflection direction and size, and the maximal intensity of the breathing solitons were manipulated. The breathing solitons of different bound states were formed by changing the phase φ, amplitude A, and initial interval x0 of two Airy beams. The results provide a theoretical basis for the propagation and manipulation of Airy beams.

Acute effects of conventional versus wide-pulse neuromuscular electrical stimulation on quadriceps evoked torque and neuromuscular function.

The effectiveness of a neuromuscular electrical stimulation (NMES) program is proportional to the level of evoked torque, which can be achieved with either conventional or wide-pulse stimulations. The aim of this study was to compare evoked torque, objective fatigability, and related peripheral and central alterations, as well as changes in central nervous system (CNS) excitability induced by an acute session of conventional versus wide-pulse NMES. Seventeen young men underwent three 20-min NMES sessions: conventional (0.2 ms/50 Hz), wide-pulse at 50 Hz (1 ms/50 Hz), and wide-pulse at 100 Hz (1 ms/100 Hz). Neuromuscular measurements (i.e., maximal voluntary contraction, voluntary activation, evoked responses to femoral nerve stimulation, and CNS excitability) were performed on the right quadriceps femoris muscle before and after each NMES session. CNS excitability was measured using transcranial magnetic, thoracic, and transcutaneous spinal cord stimulations. The level of evoked torque was not significantly different between conventional and wide-pulse protocols applied at the maximal tolerable current intensity. All NMES protocols induced objective fatigability (~14% decrease in maximal voluntary contraction torque, p < 0.001) associated with peripheral (decrease in doublet torque and potentiated M-wave amplitude, p = 0.002 and p < 0.001, respectively) but not central (unchanged voluntary activation, p = 0.79) alterations. However, these acute changes did not differ between NMES protocols and none of the NMES protocols modified markers of CNS excitability. These results may allow to conjecture that chronic effects and treatment effectiveness could be comparable between conventional and wide-pulse NMES.