Plateau Duration Research Articles

Intracoronary nicardipine to induce hypaeremia

Abstract Background Several pharmacological agents and routes of administration have been used to induce transient maximal hyperaemia, but most suffer from shortcomings that limit their clinical usage. Nicardipine, a dihydropyridine calcium channel blocker, has been proposed as a coronary hyperaemic agent with the advantage of not causing any adverse effects. Purpose We compared intracoronary (IC) nicardipine with IC papaverine for obtaining fractional flow reserve (FFR) and pullback pressure gradient (PPG). Methods and results This is a prospective, single-center study enrolling stable patients presenting with intermediate coronary artery disease (CAD) undergoing invasive functional assessment. The lowest FFR, duration of the hyperemic plateau, and PPG were assessed after IC nicardipine (400 µg to the left coronary or 300 µg to the right coronary artery) and IC papaverine (12 mg to the left coronary artery and 8 mg to the right coronary artery). Results Overall, 107 patients with 108 vessels (216 FFR and 216 PPG paired measurements) were analyzed. The correlation in FFR between nicardipine and papaverine was r = 0.95 (95% CI 0.92 to 0.96, p < 0.001) with a mean difference of 0.02 FFR units (limit of the agreement [LOA]: -0.04 to 0.08). Similarly, the correlation in PPG between nicardipine and papaverine was r = 0.86 (95% CI 0.71 to 0.93, p < 0.001) with a mean difference of 0.01 PPG units (limit of the agreement [LOA]: -0.14 to 0.17). The hyperaemic plateau was significantly longer with nicardipine (101.4 ± 62.1 s nicardipine vs 41.5 ± 14.3 s papaverine, p < 0.001). No significant differences were observed in the magnitude of changes in blood pressure and heart rate (p=NS). No complications occurred with the administration of IC nicardipine or papaverine. Conclusion FFR and PPG values obtained following nicardipine administration exhibited excellent agreement with those obtained using papaverine. Moreover, the hyperaemic response induced by nicardipine led to a significantly prolonged steady state in comparison to papaverine. Given its widespread availability, cost-effectiveness, safety profile and frequent utilization in clinical settings, nicardipine emerges as the optimal vasodilator for coronary physiology testing.FFR by Nicardipine vs PapaverinePPG by Nicardipine vs Papaverine

Exploring the optimal plateau durations of tone burst to elicit masseteric vestibular evoked myogenic potentials: a within-subjects study

ObjectiveThe purpose of the present study was to explore the effect of plateau duration in eliciting masseter vestibular evoked myogenic potentials (mVEMPs) in healthy individuals with hearing sensitivity ≤ 15dBHL.MethodA within-subjects design was utilized in the study. Therefore, ipsilateral tone burst evoked mVEMPs were obtained from 30 healthy individuals using the zygomatic montage at 500 Hz tone bursts. Self-monitoring biofeedback was given during the procedure to confirm the tension of the masseter muscle. mVEMPs were recorded across three different plateau duration from 0 to 2 ms with rise/fall time of 2 ms at 95dBnHL. Hence the median and interquartile range were calculated for descriptive analysis of the data followed by non-parametric inferential statistics.ResultsTone burst evoked mVEMPs were found to be 100% present across all three plateau durations for both ears at 95 dBnHL. P11 and N21 latencies increased with longer plateau durations in both ears. There were no significant differences in P11-N21 peak-to-peak amplitude or interaural amplitude ratio (IAAR) observed across different plateau durations. IAAR was lowest for a 2 ms plateau duration in the 2–2-2 cycle. No significant variations were found across the three plateau durations.ConclusionSignificant differences in P11 and N21 latencies were observed across the three stimulus cycles, while no significant differences were found for P11N21 amplitude and IAAR. Yet, there was found to have the highest amplitude and lowest IAAR for 2–2-2 cycle than 2–0-2 and 2–1-2, suggesting it to be the optimal stimulus among the three of them.

Monitoring the evolution of optical coatings during thermal annealing with real-time, in situ spectroscopic ellipsometry

Abstract Thermal annealing plays a key role in optimizing the properties of amorphous optical coatings. In the field of gravitational wave detection (GWD), however, the effects of annealing protocols on the interferometry mirror coatings have been explored primarily by ex post analysis. As a result, the dynamics of the coatings properties during annealing is still poorly known, potentially leading to suboptimal performance. Here, using real-time, in situ spectroscopic ellipsometry (SE) we have tracked the refractive index and thickness of a titania-tantala coating during controlled annealing. We have tested the material and the annealing protocol used in
current GWD mirrors. The annealing cycle consisted of a heating ramp from room temperature to 500 °C, followed by a 10-hour plateau at the same temperature and the final cooling ramp. SE measurements have been run continuously during the entire cycle. Significant variations in the thickness and refractive index, which accompany the coating structural relaxation, have been recorded during the heating ramp. These variations start around 200 °C, slightly above the deposition temperature, and show an increased rate in the range 250-350 °C. A smaller, continuous evolution has been observed during the 10-hour high-temperature plateau. The results offer
suggestions to modify the current annealing protocol for titania-tantala coatings, for example by increasing the time duration of the high-temperature plateau. They also suggest an increase in the substrate temperature at deposition. The approach presented here paves the way for systematic, real-time investigations to clarify how the annealing parameters shape the properties of optical coatings, and can be leveraged to define and optimize the annealing protocol of new candidate materials for GWD mirrors.

Heavy-intensity priming exercise extends the V̇o2max plateau and increases peak-power output during ramp-incremental exercise.

This study investigated whether a heavy-intensity priming exercise precisely prescribed within the heavy-intensity domain would lead to a greater peak-power output (POpeak) and a longer maximal oxygen uptake (V̇o2max) plateau. Twelve recreationally active adults participated in this study. Two visits were required: 1) a step-ramp-step test [ramp-incremental (RI) control], and 2) an RI test preceded by a priming exercise within the heavy-intensity domain (RI primed). A piecewise equation was used to quantify the V̇o2 plateau duration (V̇o2plateau-time). The mean response time (MRT) was computed during the RI control condition. The delta (Δ) V̇o2 slope (S; mL·min-1·W-1) and V̇o2-Y intercept (Y; mL·min-1) within the moderate-intensity domain between conditions (RI primed minus RI control) were also assessed using a novel graphical analysis. V̇o2plateau-time (P = 0.001; d = 1.27) and POpeak (P = 0.003; d = 1.08) were all greater in the RI primed. MRT (P < 0.001; d = 2.45) was shorter in the RI primed compared with the RI control. A larger ΔV̇o2plateau-time was correlated with a larger ΔMRT between conditions (r = -0.79; P = 0.002). This study demonstrated that heavy-intensity priming exercise lengthened the V̇o2plateau-time and increased POpeak. The overall faster RI-V̇o2 responses seem to be responsible for the longer V̇o2plateau-time. Specifically, a shorter MRT, but not changes in RI-V̇o2-slopes, was associated with a longer V̇o2plateau-time following priming exercise.NEW & NOTEWORTHY It remains unclear whether priming exercise extends the maximal oxygen uptake (V̇o2max) plateau and increases peak-power output (POpeak) during ramp-incremental (RI) tests. This study demonstrates that a priming exercise, precisely prescribed within the heavy-intensity domain, extends the plateau at V̇o2max and leads to a greater POpeak. Specifically, the extended V̇o2max plateau was associated with accelerated RI-V̇o2 responses.

Modeling the Progenitor Stars of Observed Type IIP Supernovae

Type IIP supernovae (SNe IIP) are thought to originate from the explosion of massive stars >10 M ⊙. Their luminosity is primarily powered by the explosion energy and the radioactive decay energy of 56Co, with the photosphere location regulated by hydrogen recombination. However, the physical connections between SNe IIP and their progenitor stars remain unclear. This paper presents a comprehensive study of SNe IIP and their progenitor stars by using the one-dimensional stellar evolution code, MESA. Our model grids consider the effects of stellar metallicity, mass, and rotation in the evolution of massive stars, as well as the explosion energy and 56Ni production in modeling supernovae. To elucidate the observed SNe IIP and their origins, we compare their light curves (LCs) with our models. Furthermore, we investigate the impact of stellar parameters on LCs by considering stellar mass, metallicity, rotation, explosion energy, and 56Ni production. We find that more massive stars exhibit longer plateaus due to increased photon diffusion time caused by massive ejecta. Higher metallicity leads to increased opacity and mass loss of progenitor stars. Rapid rotation affects internal stellar structures, enhancing convective mixing and mass loss, potentially affecting the plateau’s brightness and duration. Higher explosion energy results in brighter but shorter plateaus due to faster-moving ejecta. 56Ni mass affects late-time luminosity and plateau duration, with larger masses leading to slower declines.

The impact of surgery resident training on the duration of tibial plateau leveling osteotomy surgery.

To investigate the impact of surgery resident training on surgery duration in tibial plateau leveling osteotomy (TPLO) and evaluate whether surgery duration differs with each year of residency training. Retrospective medical record review. A total of 256 client-owned dogs underwent TPLO. Records of dogs that underwent TPLO between August 2019 and August 2022 were reviewed. The effects of the surgeon (faculty/resident) and the procedure (arthrotomy/arthroscopy) on TPLO surgery duration were examined with an analysis of variance, and geometric least squares means (GLSM) were compared. A linear mixed effects model (LMM) was fitted to quantify fixed and random effects. Four faculty surgeons performed 74 (29%) TPLOs, while 10 residents performed 182 (71%) TPLOs under the direct supervision of a faculty surgeon. All TPLOs were conducted with arthrotomy (109; 43%) or arthroscopy (147; 57%). Overall, residents (GLSM, 153 min) required 54% more surgery duration than faculty surgeons (GLSM, 99 min). Surgery duration among first-year residents (GLSM, 170 min) was 15% longer than second- (GLSM, 148 min) and third-year (GLSM, 147 min) residents, whereas the duration did not differ statistically between second- and third-year residents. Arthroscopy, meniscal tear treatment, surgery on the right stifle, and increasing patient weight were also associated with longer surgery duration. The duration of TPLO surgery significantly decreased after the first year of residency, but did not decrease afterward. The results will aid with resource allocation, curricula planning, and cost management associated with resident training.

Triple point of carbon dioxide: using a new calibration point of the International Temperature Scale ITS-90

One of the important tasks of improving the International Temperature Scale ITS-90 is considered – the substitution of the fixed point of mercury (Hg) in connection with the ratification of the Minamata Convention and restrictions on the extraction, use and transportation of mercury. Reported results of experimental calibration of long-stem standard platinum resistance thermometers using a new calibration point from the list of secondary fixed points of the International Temperature Scale ITS-90. A method has been developed to realize the triple point of carbon dioxide (CO2) using liquid nitrogen. The method reduced the preparation time of the cell from 60 to 30 minutes and increased the duration of melting plateau from 10 to 40 hours. Presented results of two calibrations cases: using the fixed-point of Hg; using the triple point of CO2 instead of fixed-point Hg. Described methods to evaluate propagation of calibration uncertainty based on the fixed-point sensitivity coefficients. The fixed-points sensitivity coefficients for two subranges of standard platinum resistance thermometers calibration are analyzed and it is shown that the calibration uncertainty using the triple point of CO2 is reduced by half in the range of –189.3442...+ 0.01 °C and by 1.5 times in the range of –60...+ 60 °C. The results confirm the possibility and prospects of using the CO2 triple point as a new calibration point to substitute the fixed-point Hg.

The Economic Evaluation of Various Production Scenarios for Zubair Reservoir in the Kifl Field

This work evaluates the economic feasibility of various production scenarios for the Zubair reservoir in the Kifl oil field using cash flow and net present value (NPV) calculations. The Kifl field is an exploratory field that has not yet been developed or assessed economically. The first well was drilled in 1960, and three other wells were later drilled to assess the oil accumulation, so in this research, Different production scenarios were evaluated economically. These scenarios were proposed based on the reservoir model of the Zubair formation in the field. The research methodology used QUE$TOR software to estimate capital expenditures (CapEx) and operating expenditures (OpEx) based on field-level data, production profiles for each scenario, and produced fluid properties. CapEx estimates were mainly based on the number of drilled wells and plateau duration, while OpEx estimates were based on the number of barrels produced from each scenario. Cash flow values were estimated each year in the production interval after subtracting water handling costs, CapEx, and OpEx from the gross revenue of oil produced. The NPV for each scenario was then calculated using a 5% interest rate, and the most economical option was determined by comparing the NPV values of each scenario. Case-3 scenario was identified as the most economical option, with a high NPV value of approximately 612 MM$, an oil production rate of 10 MSTB/d, a Plateau duration of 3 years, a total number of wells of 11, and an Initial water cut of 13 %.

Convective-core overshooting and the final fate of massive stars

A massive star can explode in powerful supernova (SN) and form a neutron star, but it may also collapse directly into a black hole. Understanding and predicting the final fate of such stars is increasingly important, for instance, in the context of gravitational-wave astronomy. The interior mixing of stars (in general) and convective boundary mixing (in particular) remain some of the largest uncertainties in their evolution. Here, we investigate the influence of convective boundary mixing on the pre-SN structure and explosion properties of massive stars. Using the 1D stellar evolution code MESA, we modeled single, non-rotating stars of solar metallicity, with initial masses of 5 − 70 M⊙ and convective core step-overshooting of 0.05 − 0.50 pressure scale heights. Stars were evolved until the onset of iron core collapse and the pre-SN models were exploded using a parametric, semi-analytic SN code. We used the compactness parameter to describe the interior structure of stars at core collapse and we found a pronounced peak in compactness at carbon-oxygen core masses of MCO ≈ 7 M⊙, along with generally high compactness at MCO ≳ 14 M⊙. Larger convective core overshooting will shift the location of the compactness peak by 1 − 2 M⊙ to higher MCO. These core masses correspond to initial masses of 24 M⊙ (19 M⊙) and ≳40 M⊙ (≳30 M⊙), respectively, in models with the lowest (highest) convective core overshooting parameter. In both high-compactness regimes, stars are found to collapse into black holes. As the luminosity of the pre-supernova progenitor is determined by MCO, we predict black hole formation for progenitors with luminosities of 5.35 ≤ log(L/L⊙)≤5.50 and log(L/L⊙)≥5.80. The luminosity range of black hole formation from stars in the compactness peak is in good agreement with the observed luminosity of the red supergiant star N6946 BH1, which disappeared without a bright supernova, indicating that it had likely collapsed into a black hole. While some of our models in the luminosity range of log(L/L⊙) = 5.1 − 5.5 do indeed collapse to form black holes, this does not fully explain the lack of observed SN IIP progenitors at these luminosities. This case specifically refers to the “missing red supergiant” problem. The amount of convective boundary mixing also affects the wind mass loss of stars, such that the lowest black hole masses are 15 M⊙ and 10 M⊙ in our models, with the lowest and highest convective core overshooting parameter, respectively. The compactness parameter, central specific entropy, and iron core mass describe a qualitatively similar landscape as a function of MCO, and we find that entropy is a particularly good predictor of the neutron-star masses in our models. We find no correlation between the explosion energy, kick velocity, and nickel mass production with the convective core overshooting value, but we do see a tight relation with the compactness parameter. Furthermore, we show how convective core overshooting affects the pre-supernova locations of stars in the Hertzsprung–Russell diagram (HRD) and the plateau luminosity and duration of SN IIP light curves.

Construction of Numerical PVT-Models for the Bulla-Daniz Gas-Condensate Field Based on Laboratory Experiments on Reservoir Fluid Samples

PVT analysis is important for field-wide optimization and development. This is because we must understand the fluid's overall behavior from the reservoir to the production and processing facilities, and ultimately to the refinery. Modern computer software that uses equation of state (EOS) models to simulate experiments and illustrate fluid phase characteristics has contributed to its growth as a distinct field of study. To find the operating parameters that will maximize the surface liquid content and prolong the production plateau duration at the lowest feasible cost, PVT simulations are run. These simulations employ laboratory-derived data to fine-tune the EOS models, with the outcomes being integrated into reservoir simulation and research. The quality of the data is crucial to getting a good match between EOS and laboratory data, and for retrograde gas condensates, this can be particularly difficult because of their complex phase behavior. When utilized in reservoir simulations, an inadequate match leads to computational mistakes and unrepresentative findings, endangering the reservoir management decisions that depend on it.

Numerical analysis of dynamic collapse response of beam–column substructures under impact loads

To investigate the collapse resistance performance of steel-frame structures at varying scale ratios, numerical simulations were performed to scrutinize the influence of different scale ratios on the dynamic response of beam–column substructures subjected to impact loads. In this study, two drop-hammer impact tests were modeled and simulated, their results were compared, and the accuracy of the finite element modeling method was verified. Concurrently, a detailed model of a double half-span beam–column substructure was established to examine the effect of impact energy variations (altering the mass and velocity of the drop hammer) on the structural impact force and vertical displacement. This study analyzed variations in the impact force, impact time history, vertical displacement, internal forces, and energy absorption for models with different scale ratios when altering the impact energy. Finite element analysis results indicated that the impact velocity of the drop hammer affected the peak impact force of the substructure, whereas the drop-hammer mass influenced the force plateau and impact duration. Both the impact duration and maximum vertical displacement were positively correlated with the impact of the drop hammer and were approximately linearly positively correlated with the impact kinetic energy, resulting in the establishment of a linear fitting model between the maximum vertical displacement and the impact energy. For scaled-down substructures, variations in the impact energy could be achieved by adjusting the drop-hammer impact velocity (drop height). A proposed scale ratio for the substructure drop-hammer impact anti-collapse test is provided.

Voltage- and Calcium-Gated Membrane Currents Tune the Plateau Potential Properties of Multiple Neuron Types.

Many neurons exhibit regular firing that is limited to the duration and intensity of depolarizing stimuli. However, some neurons exhibit all-or-nothing plateau potentials that, once elicited, can lead to prolonged activity that is independent of stimulus intensity or duration. To better understand this diversity of information processing, we compared the voltage-gated and Ca2+-gated currents of three identified neurons from hermaphroditic Aplysia californica Two of these neurons, B51 and B64, generated plateau potentials and a third neuron, B8, exhibited regular firing and was incapable of generating a plateau potential. With the exception of the Ca2+-gated potassium current (I KCa), all three neuron types expressed a similar array of outward and inward currents, but with distinct voltage-dependent properties for each neuron type. Inhibiting voltage-gated Ca2+ channels with Ni+ prolonged the plateau potential, indicating I KCa is important for plateau potential termination. In contrast, inhibiting persistent Na+ (I NaP) blocked plateau potentials, empirically and in simulations. Surprisingly, the properties and level of expression of I NaP were similar in all three neurons, indicating that the presence of I NaP does not distinguish between regular-firing neurons and neurons capable of generating plateau potentials. Rather, the key distinguishing factor is the relationship between I NaP and outward currents such as the delayed outward current (I D), and I KCa We then demonstrated a technique for predicting complex physiological properties such as plateau duration, plateau amplitude, and action potential duration as a function of parameter values, by fitting a curve in parameter space and projecting the curve beyond the tested values.SIGNIFICANCE STATEMENT Plateau potentials are intrinsic properties of neurons that are important for information processing in a wide variety of nervous systems. We examined three identified neurons in Aplysia californica with different propensities to generate a plateau potential. No single conductance was found to distinguish plateau generating neurons. Instead, plateau generation depended on the ratio between persistent Na+ current (I NaP), which favored plateaus, and outward currents such as I KCa, which facilitated plateau termination. Computational models revealed a relationship between the individual currents that predicted the features of simulated plateau potentials. These results provide a more solid understanding of the conductances that mediate plateau generation.

ERG K+ channels mediate a major component of action potential repolarization in lymphatic muscle

Smooth muscle cells in the walls of collecting lymphatic vessels fire spontaneous action potentials (APs), which conduct rapidly over the muscle layer to initiate contractions that propel lymph. Several ion channels have been implicated in the currents underlying the AP spike and the preceding diastolic depolarization, but the molecular identities of K+ channels involved in AP repolarization are unknown. Based on previous studies of other rhythmically active smooth muscles, we hypothesized that ether-a-go-go related gene (ERG) K+ channels (Kv11) play an important role in repolarization of the AP in lymphatic muscle. Message for one or more ERG channel isoforms was detected by RT-PCR analysis of lymphatic vessels from mice, rats and humans. Membrane potential recordings in smooth muscle cells of rat and human lymphatics revealed that nanomolar concentrations of ERG-1 inhibitors (E-4031 and BeKm-1) prolonged the duration of the AP plateau (normally ~ 1 s in duration) and induced multiple spikes, whereas ERG-1 activators (ICA-105574 and RPR-260243) shortened the plateau and could completely inhibit spontaneous APs. At relatively high inhibitor concentrations, the AP plateau duration lasted as long as 24 s. ERG activators reversed the effects of ERG inhibitors and vice-versa. In pressure myograph studies, ERG channel inhibition prolonged the diastolic repolarization phase of the contraction cycle and reduced the frequency of spontaneous contractions. This is the first evidence for a specific K+ channel contributing to the AP in lymphatic muscle. Our results imply that lymphatic contractile dysfunction may occur in long QT type II patients with mutations that result in ERG channel loss-of-function or impaired trafficking of the channel to the cell membrane.

Light Curves of Type IIP Supernovae from Neutrino-driven Explosions of Red Supergiants Obtained by a Semianalytic Approach

Type IIP supernovae (SNe IIP) mark the explosive death of red supergiants (RSGs), evolved massive stars with an extended hydrogen envelope. They are the most common supernova type and allow for the benchmarking of supernova explosion models by statistical comparison to observed population properties rather than by comparing individual models and events. We construct a large synthetic set of SNe IIP light curves (LCs) using the radiation hydrodynamics code SNEC and explosion energies and nickel masses obtained from an efficient semianalytic model for two different sets of stellar progenitor models. By direct comparison, we demonstrate that the semianalytic model yields very similar predictions as alternative phenomenological explosion models based on 1D simulations. We find systematic differences of a factor of ∼2 in plateau luminosities between the two progenitor sets due to different stellar radii, which highlights the importance of the RSG envelope structure as a major uncertainty in interpreting the LCs of SNe IIP. A comparison to a volume-limited sample of observed SNe IIP shows decent agreement in plateau luminosity, plateau duration, and nickel mass for at least one of the synthetic LC sets. The models, however, do not produce sufficient events with very small nickel mass M Ni < 0.01 M ⊙ and predict an anticorrelation between plateau luminosity and plateau duration that is not present in the observed sample, a result that warrants further study. Our results suggest that a better understanding of RSG stellar structure is no less important for reliably explaining the LCs of SNe IIP than the explosion physics.

Modeling of discharge characteristics and plasma chemistry in atmospheric CO2 pulsed plasmas employing deep neural network

In recent years, non-thermal plasma technology has emerged as one of the most promising candidates for decomposing CO 2. The fluid model, a powerful tool to investigate the plasma dynamics, is computationally costly in simulating complex CO 2 plasma with tens of particles and hundreds of reactions, especially driven by short pulsed voltages. In this paper, a deep neural network (DNN) is proposed to describe the discharge characteristics and plasma chemistry of CO 2 pulsed discharge at atmospheric pressure. The DNN is trained using the simulation data obtained from the fluid model and then continuously optimized by minimizing the loss function. The effectiveness and feasibility of the DNN are verified by comparing with the experimental measurement and the numerical simulation results. Compared to the time-consuming fluid simulations with tens of hours, the well-trained DNN typically requires only a few seconds to obtain the essential characteristics of CO 2 pulsed discharges with high accuracy, significantly improving the computational efficiency. The DNN prediction results show that increasing the pulse rise rate at a given voltage amplitude can effectively raise the discharge current and breakdown voltage, and the electric field in the sheath region also increases with the pulse rise rate. In addition, the density of the surface charge accumulated on the dielectric layer increases with the plateau duration, and then a strong induced electric field by the surface charges is established, which obviously improves the discharge current during the pulse fall phase. The predicted data also show that increasing the pulse rise rate and the plateau duration could effectively improve the density of product species, such as CO and O 2, leading to an increase in CO 2 conversion. This study demonstrates that the DNN method is a reliable tool for obtaining the essential discharge characteristics of atmospheric CO 2 pulsed plasma and provides a promising avenue for future applications of DNN-based methods in non-thermal plasmas.

The interplay of continuous milk ejection and milking system with and without prestimulation at different vacuum settings

Efficient machine milking requires an optimal interaction of alveolar milk ejection in the udder and milk removal by the milking machine. The aim of the present study was to test whether the equilibrium between continuous milk ejection and milk removal can also be maintained at very fast milking through a particularly high vacuum. Eight Holstein dairy cows were milked at 42, 52, or 60 kPa, with (PS) or without (nPS) prestimulation. Each of the 6 treatments was conducted at 2 afternoon milkings in each animal. The prestimulation lasted 40 s and consisted of forestripping and teat cleaning. The cluster attachment followed after a 20-s latency period. Throughout each milking, B-mode ultrasound videos of the gland cistern of 1 front quarter as well as milk flow and claw vacuum curves were recorded. Total milk yield was neither affected by nPS or PS nor by the vacuum level. Milk removed within the first minute and the first 2 min of milking and average milk flow were higher, and the duration of incline and time until peak milk flow were shorter at PS than at nPS milkings at all vacuum levels. Machine-on time was shorter at PS than at nPS milkings, although only at 42 and 52 kPa vacuum, obviously caused by the high percentage of bimodalities occurring in nPS milkings (17% bimodalities in PS vs. 92% bimodalities in nPS milkings). The frequency of bimodalities was higher at high than at low vacuum both in PS and nPS milkings. Peak flow rate and average milk flow were both higher at higher vacuum levels. The duration of milk flow plateau was shorter at 60 kPa than at 42 kPa milkings. At the highest vacuum (60 kPa), the shorter plateau phase indicated a declining milk ejection rate toward the end of the plateau phase, and milk ejection could no longer keep up with the fast milk removal; hence, a higher milking efficiency at a higher vacuum level could only be achieved as long as the gland cistern remained sufficiently filled by the continuous milk ejection. The ultrasound imaging confirmed this finding as the duration of cisternal area plateau in the recorded front quarter was shorter at high than at low vacuum. Thus, the highest vacuum of 60 kPa did not cause a shorter machine-on time than 52 kPa. In conclusion, milking at a very high vacuum can increase milking efficiency compared with a low vacuum. However, a vacuum reduction at the start and toward the end of milking is required to prevent overmilking if milking is performed at a very high vacuum.

Development of a high-power pulse-forming network Marx generator with a long pulse duration.

To meet the application needs for producing long-pulse electron beams and high-power microwaves, a pulse-forming network Marx generator with a pulse duration of 260ns is presented in this paper. This generator is composed of 20 stages of pulse-forming network modules. Each module is formed with nine capacitors connected in parallel. The generator functions at 44kV, which is lower than the rated voltage of the mica paper capacitor, to improve the lifetime. The impedance of the generator is designed to reach 45Ω. To avoid the strong coupling between the adjacent stages, the physical layout of the generator adopts a zigzag design. The generator is housed in a gas pressurized vessel of 600mm in diameter and 580mm in length. Across a 50Ω load, it can deliver quasi-rectangular pulses with a pulse duration of 260ns and an amplitude of 500kV for a single shot. The output pulse features a plateau duration of 160ns and a leading edge of 45ns. In burst mode, it can steadily output ten pulses of 450kV at a repetition rate of 10Hz on either a resistive load or a diode.

Counterpropagating light in ring resonators: Switching fronts, plateaus, and oscillations

We characterize the formation of robust stationary states formed by light plateaus separated by two local switching fronts in only one of two counterpropagating fields in ring resonators with normal dispersion. Such states are due to global cross coupling and allow for frequency combs to switch from one field to the other by simply tuning the input laser frequency. Exact expressions for the distance between fronts and for plateau powers are provided in excellent agreement with simulations. These demonstrate an unusual high degree of control over pulse and plateau duration in one of the fields upon changes of one of the input laser frequencies. We identify a wide parameter region in which light plateaus are self-starting and are the only stable solution. For certain values of the detunings we find multistable states of plateaus with switching fronts, slowly oscillating homogeneous states and nonoscillating homogeneous states of the counterpropagating fields. Robustness and multistability of these unusual single-field front solutions are provided in parameter ranges that are experimentally achievable in a wide variety of ring resonators.

Desaturation event scoring criteria affect the perceived severity of nocturnal hypoxic load

Objectives/BackgroundInterest in using blood oxygen desaturations in the diagnostics of sleep apnea has risen in recent years. However, no standardized criteria for desaturation scoring exist which complicates the drawing of solid conclusions from literature. Patients/methodsWe investigated how different desaturation scoring criteria affect the severity of nocturnal hypoxic load and the prediction of impaired daytime vigilance in 845 patients. Desaturations were scored based on three features: 1) minimum oxygen saturation drop during the event (2–20%, 1% interval), 2) minimum duration of the event (2–20s, 1s interval), and 3) maximum plateau duration within the event (5–60s, 5s interval), resulting in 4332 different scoring criteria. The hypoxic load was described with oxygen desaturation index (ODI), desaturation severity (DesSev), and desaturation duration (DesDur) parameters. Association between hypoxic load and impaired vigilance was investigated with covariate-adjusted area under curve (AUC) analyses by dividing patients into normal (≤5 lapses) and impaired (≥36 lapses) vigilance groups based on psychomotor vigilance task performance. ResultsThe severity of hypoxic load varied greatly between different scoring criteria. For example, median ODI ranged between 0.4 and 12.9 events/h, DesSev 0.01–0.23 %-point, and DesDur 0.3–9.6 %-point when the minimum transient drop criterion of 3% was used and other two features were altered. Overall, the minimum transient drop criterion had the largest effect on parameter values. All models with differently determined parameters predicted impaired vigilance moderately (AUC = 0.722–0.734). ConclusionsDesaturation scoring criteria greatly affected the severity of hypoxic load. However, the difference in the prediction of impaired vigilance between different criteria was rather small.

Discerning the role of IP3R1 activation by Gq/G11 signaling in murine lymphatic collecting vessel pacemaking

Collecting lymphatic vessels (cLVs) exhibit spontaneous contractions with a pressure‐dependent frequency that increases with elevations in intraluminal pressure. Our recent work posits a putative role for lymphatic muscle cells (LMCs) as the pacemaker cell that regulates this pressure‐dependent phenomenon through activation of the Ca2+‐activated chloride channel anoctamin 1 (Ano1) in an IP3R1‐dependent process. However, the specific mechanisms underlying IP3R1 activation and SR Ca2+ release in lymphatic muscle cells is unknown. We tested the hypothesis that cLV pressure‐dependent pacemaking by the IP3R1‐Ano1 axis is downstream of the canonical Gq/G11‐PLC‐β signaling pathway. To this end, we crossed mice with the smooth muscle‐specific tamoxifen‐inducible Cre, MYH11CreERT2, to the fluorescent reporter ROSAmT/mG and sorted GFP+ LMCs from an isolated murine inguinal‐axillary (IngAx) lymphatic cLVs. Murine lymphatic muscle cell expression of Gq and G11 were assessed via RT‐PCR. We crossed MYH11CreERT2 mice with IP3R1fl/fl or G11KO/KO‐Gqfl/fl mice to achieve IP3R1ismKO (MYH11CreERT2‐IP3R1fl/fl) and double G11KO‐GqismKO (MYH11CreERT2‐ G11KO/KO‐Gqfl/fl) mice. We tested the function of the IngAx cLVs isolated from these mice, as well as their respective heterozygous WT/KO and fl/fl controls, using isolated vessel isobaric myography. Ca2+ imaging using IP3R1ismKO‐GCaMP6f mice, and membrane potential recordings using sharp electrodes. IngAx cLVs from G11KO‐GqismKO mice displayed a significant reduction in contraction frequency and vessel tone, however a pressure‐dependent increase in frequency was observed. Similarly, IngAx cLVs isolated from IP3R1ismKO mice had significantly lower vessel tone, a significant reduction in contraction frequency at all pressures tested, and a significantly higher contraction amplitude. Critically, contraction frequency in IngAx cLVs isolated from IP3R1ismKO mice did not increase with pressure in contrast to IngAx cLVs isolated from G11KO‐GqismKO mice and wildtype mice. In wildtype (WT) MYH11CreERT2‐GCaMP6f controls, Ca2+ puffs and/or Ca2+ waves were observed in the majority of LMCs during the diastolic period, intervening the bright global Ca2+ flashes indicative of Ca2+ entry through L‐type Ca2+ channels during the LMC action potential (AP). These local diastolic Ca2+ transients (CaTs) persisted in the presence of nifedipine, and the frequency and spatial spread of CaTs increased with pressure. Diastolic CaTs were largely absent in LMCs of IP3R1ismKO mice, and their diastolic depolarization recapitulated the lower rate observed in previous studies of Ano1smKO cLVs. However, APs recorded in IP3R1ismKO significantly increased AP plateau duration that corresponds with an increased Ca2+ flash duration. We conclude that the Gq/G11 dependent signaling is involved in pressure‐dependent pacemaking in murine cLVs, particularly at low pressure, but their deletion is insufficient to reproduce the IP3R1ismKO phenotype.