High Intensity Research Articles

PAINFUL VS NON-PAINFUL EXERCISE ON CREPITUS IN PEOPLE WITH KNEE OSTEOARTHRITIS: A MIXED-METHODS ANALYSIS

INTRODUCTION & AIMS Crepitus (or physiological noise) is a key criterion in the diagnosis of knee osteoarthritis (OA). Exercise is foundational to guideline-based care for knee OA, however the effect exercise on knee crepitus is unknown. This study aimed to explore the perceptions of people with knee OA following a 6-week accredited exercise physiologist (AEP) led intervention involving painful vs non-painful exercise, especially in relation to their knee crepitus. METHODS Participants were randomly assigned to either a painful (higher intensity) or non-painful (lower intensity) exercise program supervised by an AEP twice a week for six weeks with concurrent education. Volunteers partook in a post-intervention semi-structured interview with questions surrounding their experience and perceived outcomes of the program. Thematic qualitative analysis was conducted and compared to the Knee Injury and Osteoarthritis Outcome Score (KOOS) crepitus question (0 - 4 scale). RESULTS Eleven participants volunteered. Qualitatively, approximately half of the participants self-reported a decrease in their knee crepitus following the program “I haven’t had the creaky knees so much”, with the rest stating their crepitus did not change. No participants perceived their crepitus increased (n=9 no change, n=2 decreased) or said that their crepitus was worse, “the noise and grinding doesn’t become evident (now) until the weights become higher”. Quantitatively, KOOS crepitus scores also did not change following the intervention [mean (SD) (2.4(1.0) to 2.1(1.3), p=0.19)]. There were no differences between exercise groups in self-perceived crepitus results, and most said that the exercise program was beneficial “Right after this whole program, I find that I can move much easier.” CONCLUSION Exercise at higher intensities (into painful range) does not change crepitus or may improve it for some. People with OA perceive that exercise at both higher and lower intensity is beneficial and enjoyable.

Relative pedaling forces are low during cycling

We quantified and compared the mechanical force demands relative to the maximum dynamic force (MDF) of 11 cyclists when pedaling at different intensities (ventilatory threshold, maximum lactate steady state, respiratory compensation point, and maximal aerobic power), cadences (free, 40, 60 and 80 rpm), and all-out resisted sprints. Relative force demands (expressed as %MDF) progressively increased with higher intensities (p < 0.001) and lower cadences (p < 0.001). Notwithstanding, relative force demands were low (<54 % MDF) for all conditions, even during the so-called ‘torque training’. These results might be useful when programming on-bike resistance training to improve torque production capacity.

Status update of the ATLAS ECR ion sources at Argonne National Laboratory

The Argonne Tandem Linac Accelerator System (ATLAS) at Argonne National Laboratory (ANL) typically operates 24/7 with weekly ion beam changes and an annual 1 month maintenance period. Due to recent installations and upgrades at ATLAS, user demands for new beams and higher intensities have expanded an already diverse operational envelope of both electron cyclotron resonance ion sources (ECRIS), ECR2 and ECR3. A variety of material introduction techniques including sputter, oven, reduction and gas feed were used to meet the challenge of an intense run schedule. With two ECRIS available to feed the accelerator, beam development and preparation were able to occur concurrently with ATLAS programmatic activities. Highlights of operational experiences and improvements with ECR2 and ECR3 over the last 2 years are presented.

Clear speech effects in production of sentence-medial Mandarin lexical tonesa).

Adding to limited research on clear speech in tone languages, productions of Mandarin lexical tones were examined in pentasyllabic sentences. Fourteen participants read sentences imagining a hard-of-hearing addressee or a friend in a casual social setting. Tones produced in clear speech had longer duration, higher intensity, and larger F0 values. This style effect was rarely modulated by tone, preceding tonal context, or syllable position, consistent with an overall signal enhancement strategy. Possible evidence for tone enhancement was observed only in one set of analysis for F0 minimum and F0 range, contrasting tones with low targets and tones with high targets.

Identifying bias in models that detect vocal fold paralysis from audio recordings using explainable machine learning and clinician ratings.

Detecting voice disorders from voice recordings could allow for frequent, remote, and low-cost screening before costly clinical visits and a more invasive laryngoscopy examination. Our goals were to detect unilateral vocal fold paralysis (UVFP) from voice recordings using machine learning, to identify which acoustic variables were important for prediction to increase trust, and to determine model performance relative to clinician performance. Patients with confirmed UVFP through endoscopic examination (N = 77) and controls with normal voices matched for age and sex (N = 77) were included. Voice samples were elicited by reading the Rainbow Passage and sustaining phonation of the vowel "a". Four machine learning models of differing complexity were used. SHapley Additive exPlanations (SHAP) was used to identify important features. The highest median bootstrapped ROC AUC score was 0.87 and beat clinician's performance (range: 0.74-0.81) based on the recordings. Recording durations were different between UVFP recordings and controls due to how that data was originally processed when storing, which we can show can classify both groups. And counterintuitively, many UVFP recordings had higher intensity than controls, when UVFP patients tend to have weaker voices, revealing a dataset-specific bias which we mitigate in an additional analysis. We demonstrate that recording biases in audio duration and intensity created dataset-specific differences between patients and controls, which models used to improve classification. Furthermore, clinician's ratings provide further evidence that patients were over-projecting their voices and being recorded at a higher amplitude signal than controls. Interestingly, after matching audio duration and removing variables associated with intensity in order to mitigate the biases, the models were able to achieve a similar high performance. We provide a set of recommendations to avoid bias when building and evaluating machine learning models for screening in laryngology.

Comparison of conventional and severe shot peening effects on the microstructure, texture, roughness, hardness, and electrochemical behavior of austenitic stainless steel

In the present research, microstructure, texture, roughness, hardness, and electrochemical behavior of AISI 316L austenitic stainless steel before and after shot peening were studied to elucidate the effect of conventional and severe shot peening (CSP and SSP) processes. After the shot peening, the fraction of strain-induced martensite (SIM) and mechanical twins (MTs) in the sub-surface layer was increased. The fraction of SIM and MTs in the SSP sample was higher than in the CSP sample. The XRD patterns indicated that the SSP sample had a higher peak broadening compared to the CSP sample. In the CSP and SSP samples, a gradient microstructure was formed along the depth direction. The microstructure of the topmost layer of the CSP and SSP samples exhibited numerous ultrafine grains. The grain refining during severe shot peening was faster because of the accumulation of more strain. The CSP and SSP samples revealed a gradient distribution of elements. After the SSP, the intensity of ⟨110⟩‖ED fiber texture decreased from 12.7 to 11.6 × R and the average intensity of ⟨100⟩‖ED fiber texture increased from 1.7 to 2.0 × R, respectively, compared to the CSP sample. The surface roughness of the SSP sample (Rq = 73.6 nm and Ra = 45.2 nm) was lower than that of the CSP sample which represented the roughness decreased with surface coverage increasing from 100 % to 1500 %. Also, the wettability increased after the conventional and severe shot peening processes. In addition, the microhardness of the CSP and SSP samples showed a gradient distribution. The CSP sample had the lowest corrosion current density (0.13 μA/cm2) whereas the NP (non-peened) sample exhibited the highest current density (0.65 μA/cm2). The presence of ⟨100⟩-oriented grains in both CSP and SSP samples led to the higher corrosion resistance of shot-peened steels compared to the NP sample. The presence of favorable texture with higher intensity in the CSP sample was responsible for the higher corrosion resistance of the CSP sample compared to the SSP sample. Finally, the gradient distribution of elements along the depth direction in the CSP and SSP steels improved the corrosion resistance of the surface.

Comparison of Bracings and Fluid Viscous Dampers in 15-Storey Buildings across All Seismic Zones of India under Bi-Directional Excitation

Abstract: An earthquake is a natural phenomenon i:e, sudden horizontal movement of earth’s crust that causes sudden collapse of buildings and other structures such as large monuments, bridges etc. The damage of the building is based on the amount of magnitude and intensity of the earthquake. A building can withstand in lower intensity of earthquake. But higher intensity causes lots of damages on building or a building can suddenly collapse and causes increase in number of deaths. To mitigate these effects a control system is to be provided such as base isolations, dampers, bracings etc. The current topic is based on the behavior of linear and non linear fluid viscous damper provided at center and both side corners of 15 Storey RC building in diagonally bracing system. The building is modeled and analyzed by using ETABS software. Here IS 1983(part1): 2002 and medium soil type are to be considered for analysis with respect to all seismic zones (zone II - zone V) of India. Here linear static and response spectrum analysis are applied in each model. Results are to be drawn based on base shear, storey displacement and storey drift to understand how fluid viscous dampers helps to reduce the effects of earthquake.

Vayu bubble continuous positive airway pressure is a promising solution with favorable treatment outcomes for respiratory distress syndrome in newborns: a qualitative study in Bangladesh.

According to Bangladesh Demographic and Health Survey (2022), neonatal mortality, comprising 67% of under-5 deaths in Bangladesh, is significantly attributed to prematurity and low birth weight (LBW), accounting for 32% of neonatal deaths. Respiratory distress syndrome (RDS) is a prevalent concern among preterm and LBW infants, leading to substantial mortality. The World Health Organization (WHO) recommends bubble continuous positive airway pressure (bCPAP) therapy, but the affordability and accessibility of conventional bCPAP devices for a large number of patients become major hurdles in Bangladesh due to high costs and resource intensiveness. The Vayu bCPAP, a simple and portable alternative, offers a constant flow of oxygen-enriched, filtered, humidified, and pressurized air. Our study, conducted in five health facilities, explores the useability, acceptability, and perceived treatment outcome of Vayu bCPAP in the local context of Bangladesh. A qualitative approach was employed in special care newborn units (SCANUs) of selected facilities from January to March 2023. Purposive sampling identified nine key informants, 40 in-depth interviews with service providers, and 10 focus group discussions. Data collection and analysis utilized a thematic framework approach led by trained anthropologists and medical officers. Service providers acknowledged Vayu bCPAP as a lightweight, easily movable, and cost-effective device requiring minimal training. Despite challenges such as consumable shortages and maintenance issues, providers perceived the device as user-friendly, operable with oxygen cylinders, and beneficial during referral transportation. Treatment outcomes indicated effective RDS management, reduced hospital stays, and decreased referrals. Though challenges existed, healthcare providers and facility managers expressed enthusiasm for Vayu bCPAP due to its potential to simplify advanced neonatal care delivery. The Vayu bCPAP device demonstrated useability, acceptability, and favorable treatment outcomes in the care of neonates with RDS. However, sustained quality service necessitates continuous monitoring, mentoring and retention of knowledge and skills. Despite challenges, the enthusiasm among healthcare providers underscores the potential of Vayu bCPAP to save lives and simplify neonatal care delivery. Development of Standard Operating procedure on Vayu bCPAP is required for systematic implementation. Further research is needed to determine how the utilization of Vayu bCPAP devices enhances accessibility to efficient bCPAP therapy for neonates experiencing RDS.

Music as a countermeasure to fatigue: A driving simulator study

Listening to music while driving is a commonly adopted fatigue-coping strategy, yet its effectiveness has been explored in only a limited number of studies. Here, we aim to evaluate its impact on passive task-related driving fatigue, as measured by a set of both objective and subjective indicators.A driving simulator experiment was conducted involving 60 participants, who completed a 50-minute driving task on a monotonous highway scenario. The participants were divided into a control group, which did not listen to any music, and an experimental group, which drove for 20 min without music and then listened to a self-selected music playlist played at the preferred intensity for the remaining 30 min.Results show that music had a positive acute effect on objective measurements of driving fatigue. However, this effect was transient (15–25 min duration), and more prominently observed in subjective measures of fatigue. An exploratory analysis of song features suggests that higher intensity, higher tempo, more danceable, and less instrumental music tend to be more effective. These findings indicate that listening to music can serve as a viable short-term countermeasure to driving fatigue.

Optimization and miniaturization of SE-ECL for potential-resolved, multi-color, multi-analyte detection

Electrochemiluminescence (ECL) is a bioanalytical technique with numerous advantages, including the potential for high temporal and spatial resolution, a high signal-to-noise ratio, a broad dynamic range, and rapid measurement capabilities. To reduce the complexity of a multi-electrode approach, we use a single-electrode electrochemiluminescence (SE-ECL) configuration to achieve the simultaneous emission and detection of multiple colors for applications that require multiplexed detection of several analytes. This method exploits intrinsic differences in the electric potential applied along single electrodes built into electrochemical cells, enabling the achievement of distinct colors through selective excitation of ECL luminophores. We present results on the optimization of SE-ECL intensity for different channel lengths and widths, with sum intensities being 5 times larger for 6 cm vs. 2 cm channels and linearly increasing with the width of the channels. Furthermore, we demonstrated for the first time that applying Alternating Current (AC) voltage within the single electrode setup for driving the ECL reactions has a dramatic effect on the emitted light intensity, with square waveforms resulting in higher intensities vs sine waveforms. Additionally, multiplexed multicolor SE-ECL on a 6.5 mm × 3.6 mm CMOS semiconductor image sensor was demonstrated for the first time, with the ability to simultaneously distinguish four different colors, leading to the ability to measure multiple analytes.

Low- and moderate-intensity aerobic exercise improves the physiological acclimatization of lowlanders on the Tibetan plateau.

This study investigates whether exercise as a strategy for improving physical fitness at sea level also offers comparable benefits in the unique context of high altitudes (HA), considering the physiological challenges of hypoxic conditions. Overall, 121 lowlanders who had lived on the Tibetan Plateau for >2years and were still living at HA during the measurements were randomly classified into four groups. Each individual of the low-intensity (LI), moderate-intensity (MI), and high-intensity (HI) groups performed 20 sessions of aerobic exercise at HA (3680m) over 4weeks, while the control group (CG) did not undergo any intervention. Physiological responses before and after the intervention were observed. The LI and MI groups experienced significant improvement in cardiopulmonary fitness (0.27 and 0.35L/min increases in peak oxygen uptake [ O2peak], both p<0.05) after exercise intervention, while the hematocrit (HCT) remained unchanged (p>0.05). However, HI exercise was less efficient for cardiopulmonary fitness of lowlanders (0.02L/min decrease in O2peak, p>0.05), whereas both the HCT (1.74 %, p<0.001) and glomerular filtration rate (18.41mL/min, p<0.001) increased with HI intervention. Therefore, LI and MI aerobic exercise, rather than HI, can help lowlanders in Tibet become more acclimated to the HA by increasing cardiopulmonary function and counteracting erythrocytosis.

The Protective Effects of High-Intensity Interval Training Combined with Q10 Supplementation on Learning and Memory Impairments in Male Rats with Amyloid-β-Induced Alzheimer's Disease.

Oxidative stress plays a major role in the progression of Alzheimer's disease (AD)-related cognitive deficits. This study was done to determine the protective effects of coenzyme Q10 (CoQ10) and high-intensity interval training (HIIT) alone and in combination for eight continuous weeks, on oxidative status, cognitive functions, and histological changes in the hippocampus in amyloid-β (Aβ)-induced AD rats. Ninety male Wistar rats were randomly assigned to the sham, control, Q10 (50 mg/kg of CoQ10; P.O.), HIIT (high intensity: 4 min running at 85-90% VO2max, low intensity: 3 min running at 50-60% VO2max), Q10 + HIIT, AD, AD+Q10, AD+HIIT, and AD+Q10 + HIIT groups. The results showed that Aβ injection reduced cognitive functions in the Morris water maze (MWM) test and recognition memory in the novel object recognition test (NORT), which was accompanied by a decrease in total thiol groups, catalase, and glutathione peroxidase activities, an increase in malondialdehyde levels, and neuronal loss in the hippocampus. Interestingly, pretreatment with CoQ10, HIIT, or both, could markedly improve the oxidative status and cognitive decline in the MWM and NOR tests, and hinder neuronal loss in the hippocampus of Aβ-induced AD rats. Therefore, a combination of CoQ10 and HIIT can improve Aβ-related cognitive deficits, probably through an amelioration in hippocampal oxidative status and prevention of neuronal loss.

Revealing photoluminescence and nonlinear optical absorption characteristics of PbMo0.75W0.25O4 single crystal for optical limiting applications

Nonlinear absorption properties of PbMo0.75W0.25O4 single crystal fabricated by the Czochralski method were studied. The band gap energy of the crystal was determined as 3.12 eV. Urbach energy which represents the defect states inside the band gap was found to be 0.106 eV. PbMo0.75W0.25O4 single crystal has a broad photoluminescence emission band between 376 and 700 nm, with the highest emission intensity occurring at 486 nm and the lowest intensity peak at 547 nm, depending on the defect states. Femtosecond transient absorption measurements reveal that the lifetime of localized defect states is found to be higher than the 4 ns pulse duration. Open aperture (OA) Z-scan results demonstrate that the PbMo0.75W0.25O4 single crystal exhibits nonlinear absorption (NA) that includes two-photon absorption (TPA) as the dominant mechanism at the 532 nm excitations corresponding to 2.32 eV energy. NA coefficient (β eff ) increased from 7.24 × 10−10 m W−1 to 8.81 × 10−10 m W−1 with increasing pump intensity. At higher intensities β eff tends to decrease with intensity increase. This decrease is an indication that saturable absorption (SA) occurred along with the TPA, called saturation of TPA. The lifetime of the defect states was measured by femtosecond transient absorption spectroscopy. Saturable absorption behavior was observed due to the long lifetime of the localized defect states. Closed aperture (CA) Z-scan trace shows the sign of a nonlinear refractive index. The optical limiting threshold of PbMo0.75W0.25O4 single crystal at the lowest intensity was determined as 3.45 mJ/cm2. Results show that the PbMo0.75W0.25O4 single crystal can be a suitable semiconductor material for optical limiting applications in the visible region.

MR Diffusion-Weighted Imaging in Evaluating Immediate HIFU Treatment Response of Uterine Fibroids.

Nowadays, High Intensity Focused Ultrasound (HIFU) is a common surgery option for the treatment of uterine fibroids in China, the immediate response of which is clinically evaluated using Contrast Enhanced (CE) imaging. However, the injection of gadolinium with its potential adverse effect is of concern in CE and therefore, it deserves efforts to find a better imaging method without the need for contrast agent injection for this task. To assess the role of diffusion-weighted imaging (DWI) in evaluating the immediate therapeutic response of HIFU treatment for uterine fibroids in comparison with CE. 68 patients with 74 uterine fibroids receiving HIFU treatment were enrolled, and immediate treatment response was assessed using post-surgical DWI images. Semi-quantitative ordinal ablation quality grading and quantitative nonperfusion volume (NPV) measurement based on DWI and CE imaging were determined by two experienced radiologists. Agreement of ablation quality grading between DWI and CE was assessed using the weighted kappa coefficient, while intraobserver, interobserver and interprotocol agreements of NPV measurements within and between DWI and CE were evaluated using the intraclass correlation (ICC) and Bland-Altman analysis. Grading of immediate HIFU treatment response showed a moderate agreement between DWI and CE (weighted kappa = 0.446, p < 0.001). NPV measured in 65 fibroids with DWI of Grade 3~5 showed very high ICCs for the intraobserver and interobserver agreement within DWI and CE (all ICC > 0.980, p < 0.001) and also for the interprotocol agreement between DWI and CE (ICC = 0.976, p < 0.001). DWI could provide satisfactory ablation quality grading, and reliable NPV quantification results to assess immediate therapeutic responses of HIFU treatment for uterine fibroids in most cases, which suggests that non-contrast enhanced DWI might be potentially used as a more costeffective and convenient method in a large proportion of patients for this task replacing CE imaging.

Effects of a 10-Week Exercise and Nutritional Intervention with Variable Dietary Carbohydrates and Glycaemic Indices on Substrate Metabolism, Glycogen Storage, and Endurance Performance in Men: A Randomized Controlled Trial.

Daily nutrition plays an important role in supporting training adaptions and endurance performance. The objective of this 10-week study was to investigate the consequences of varying carbohydrate consumption and the glycaemic index (GI) together with an endurance training regimen on substrate oxidation, muscle energy storage and endurance performance under free-living conditions. Sixty-five moderately trained healthy men (29 ± 4years; VO2 peak 55 ± 8mLmin-1kg-1) were randomized to one of three different nutritional regimes (LOW-GI: 50-60% CHO with ≥ 65% of these CHO with GI < 50 per day, n = 24; HIGH-GI: 50-60% CHO with ≥ 65% CHO with GI > 70 per day, n = 20; LCHF: ≤ 50g CHO daily, n = 21). Metabolic alterations and performance were assessed at baseline (T0) and after 10weeks (T10) during a graded exercise treadmill test. Additionally, a 5km time trial on a 400-m outdoor track was performed and muscle glycogen was measured by magnet resonance spectroscopy. Total fat oxidation expressed as area under the curve (AUC) during the graded exercise test increased in LCHF (1.3 ± 2.4gmin-1 × kmh-1, p < 0.001), remained unchanged in LOW-GI (p > 0.05) and decreased in HIGH-GI (- 1.7 ± 1.5gmin-1 × kmh-1, p < 0.001). After the intervention, LOW-GI (- 0.4 ± 0.5mmol L-1 × kmh-1, p < 0.001) and LCHF (- 0.8 ± 0.7mmolL-1 × kmh-1, p < 0.001) showed significantly lower AUC of blood lactate concentrations. Peak running speed increased in LOW-GI (T0: 4.3 ± 0.4 vs. T10: 4.5 ± 0.3ms-1, p < 0.001) and HIGH-GI (T0: 4.4 ± 0.5 vs. T10: 4.6 ± 0.4ms-1), while no improvement was observed in LCHF. Yet, time trial performance improved significantly in all groups. Muscle glycogen content increased for participants in HIGH-GI (T0: 97.3 ± 18.5 vs. T10: 144.5 ± 39.8mmol L wet-tissue-1, p = 0.027) and remained unchanged in the LOW-GI and the LCHF group. At the last examination, muscle glycogen concentration was significantly higher in LOW-GI compared to LCHF (p = 0.014). Changes in fat oxidation were only present in LCHF, however, lower lactate concentrations in LOW-GI resulted in changes indicating an improved substrate metabolism. Compared to a LCHF diet, changes in peak running speed, and muscle glycogen stores were superior in LOW- and HIGH-GI diets. The low GI diet seems to have an influence on substrate metabolism without compromising performance at higher intensities, suggesting that a high-carbohydrate diet with a low GI is a viable alternative to a LCHF or a high GI diet. Clinical Trials, NCT05241730. https://clinicaltrials.gov/study/NCT05241730 . Registered 25 January 2021.

Sensory and instrumental texture profile: a study of wafer-type biscuits from different commercial brands

Sensory analysis is applied in different sectors of the food industry, facilitatingthe evaluation of qualitative and quantitative aspects of food. Among these aspects, texture, defined as the mechanical, geometrical, and surface properties of a product, perceived by visual, tactile, and auditory human receptors, is an indispensable parameter in the preparation of biscuits. The present study aimed to define the texture profile of six different brands of wafer-type biscuits. For the pre-selection of the judges, the triangular test was applied, and the judges who discerned different samples went on to the training. The training consisted of setting four attributes, namely, fracturability, adhesiveness, chewability, and hardness. Food was served as reference standards, from the least intense to the most intense for each attribute. In the descriptive test, samples were served individually and the judges were asked to explain their initial perception, chewing experience, and residual sensations. The hardness test was performed on a texturometer by compressing the samples and the instrumental results were compared to the sensory findings. Out of 30 judges in the triangular test, 22 were able to participate in the training, only 12 attended, 9 succeeded 80% of the standards, thus participating in the descriptive test. Comparing the instrumental part with the response of the sensory analysis, a good correlation was observed, with the same divergences between some brands. The C sample was considered by the judges as intermediate, and the same as the hardness with higher intensity, the E sample obtained similar results for both evaluations, where it presented a hardness parameter varying from weak to intermediate.

Bubble dynamics and atomization of acoustically levitated diesel and biodiesel droplets using femtosecond laser pulses

This study focuses on the bubble dynamics and associated breakup of individual droplets of diesel and biodiesel under the influence of femtosecond laser pulses. The bubble dynamics were examined by suspending the droplets in the air through an acoustically levitated setup. The laser pulse energies ranged from 25 to 1050 µJ, and droplet diameters varied between 0.25 and 1.5 mm. High-speed shadowgraphy was employed to examine the influence of femtosecond laser intensity and multiple laser pulses on various spatial–temporal parameters. Four distinct sequences of regimes have been identified, depending on early and late times: bubble creation by individual laser pulses, coalescence, bubble rupture and expansion, and droplet fragmentation. At all laser intensities, early-time dynamics showed only bubble generation, while specifically at higher intensities, late-time dynamics revealed droplet breaking. The droplet breakup is further categorized into three mechanisms: steady sheet collapse, unstable sheet breakup, and catastrophic breakup, all following a well-known ligament and secondary breakup process. The study reveals that laser pulses with high repetition rates and moderate laser energy were the optimal choice for precise bubble control and cutting.

Tidal, density and wind-driven subtidal circulation in a hypersaline coastal lagoon

Subtidal circulation patterns were studied along an elongated hypersaline system. Month-long data were collected using three acoustic Doppler current profilers. These profilers were moored at depths of around 15 m in three locations: 10 km inland from the mouth of the lagoon, within the central region, and near the head of the lagoon. The variability of temporal and spatial subtidal circulation was explored using Empirical Orthogonal Functions analysis, which explained 93% of the variability through the first three modes. The first mode was influenced by tidal advection, resulting in a tidally-driven residual circulation for elongated channels, with inflows occurring over the shoals and outflows in the deeper channel sections. During the neap-tide cycle, inverse density gradients became relevant, coinciding with the peaks of mode 2 amplitude that accounted for 15% of the total variability. The gravitational circulation exhibited its highest intensity near the head, characterized by a vertically sheared flow with inflow occurring near the surface and outflow underneath. Predominant onshore wind stresses had a significant impact on the subtidal circulation and displayed a strong correlation with the mode 3 amplitude, explaining 11% of the total variability. Wind-driven circulation exhibited a vertically sheared profile, characterized by downwind near-surface flow and upwind flow underneath in the lagoon mouth and head, and a homogeneous downwind profile in the central part of the lagoon. It is concluded that tidal stresses governed the subtidal circulation, followed by density gradients, and wind stresses modified spatial circulation patterns induced by tides and density gradients. This research provides new observational evidence on tidal residuals in long channels and contributes to the understanding of the interactions between the main subtidal circulation drivers in hypersaline lagoons.

Proposal and practicality of an alternative blue-light hazard risk assessment method for high-intensity white-light sources at workplaces

Objectives. It is prescribed to determine blue-light hazard (BLH) weighted radiances, L B , for an assessment of spotlights with an angular subtense α ≥ 11 mrad . The BLH weighted irradiance, E B , can be used alternatively for smaller sources. Appropriate instruments are not common among persons commissioned with risk assessment (RA), and especially L B measurements may be challenging. Therefore, a practical BLH RA approach is proposed that is based on illuminance, E v , pre-calculated blackbody BLH efficacies of luminous radiation, K B,v Planck , and solid angle considerations. Methods. The practicality of this method was examined and compared against other RA approaches. Results. To ensure comparability of the applied instruments, measurements were performed close to a radiance standard, showing deviations within the lamp’s expanded uncertainties ( < 4 % ), whereas the deviations were ± 15 % for longer distances. Focusing on a complex light-emitting diode (LED) spotlight, all detected values could be converted to L B by means of the RA methods within ± 20 % . Two field tests with several spotlights yielded maximum permissible exposure durations (MPED) obtained from the different RA approaches that agreed among each other within uncertainties largely below ± 30 % . Conclusion. The general practicality of the proposed E v method can be concluded for a workplace BLH RA of white-light sources.

Intensity- and frequency-specific effects of transcranial alternating current stimulation are explained by network dynamics

Objective. Transcranial alternating current stimulation (tACS) can be used to non-invasively entrain neural activity and thereby cause changes in local neural oscillatory power. Despite its increased use in cognitive and clinical neuroscience, the fundamental mechanisms of tACS are still not fully understood. Approach. We developed a computational neuronal network model of two-compartment pyramidal neurons (PY) and inhibitory interneurons, which mimic the local cortical circuits. We modeled tACS with electric field strengths that are achievable in human applications. We then simulated intrinsic network activity and measured neural entrainment to investigate how tACS modulates ongoing endogenous oscillations. Main results. The intensity-specific effects of tACS are non-linear. At low intensities (<0.3 mV mm−1), tACS desynchronizes neural firing relative to the endogenous oscillations. At higher intensities (>0.3 mV mm−1), neurons are entrained to the exogenous electric field. We then further explore the stimulation parameter space and find that the entrainment of ongoing cortical oscillations also depends on stimulation frequency by following an Arnold tongue. Moreover, neuronal networks can amplify the tACS-induced entrainment via synaptic coupling and network effects. Our model shows that PY are directly entrained by the exogenous electric field and drive the inhibitory neurons. Significance. The results presented in this study provide a mechanistic framework for understanding the intensity- and frequency-specific effects of oscillating electric fields on neuronal networks. This is crucial for rational parameter selection for tACS in cognitive studies and clinical applications.