Ms Pulse Width Research Articles

Comparisons of different electrical stimulation modalities for treating visceral pain in a rodent model of irritable bowel syndrome

The purpose of this study was to investigate the effects of different electrical stimulation methods (bilateral electroacupuncture (BEA), unilateral EA (UEA), transcutaneous electrical acustimulation (TEA, stimulation via surface electrodes placed at acupoints), and sacral nerve stimulation (SNS)) on visceral pain in a rodent model of irritable bowel syndrome (IBS). Ten-day-old male and female pups were treated with 0.2 ml of 0.5% acetic acid (AA) solution. Visceral sensitivity was assessed using an electromyogram (EMG) in response to graded colorectal distension. In the first experiment, bilateral EA at ST36 acupoint was performed with different parameters in male rats to determine the best stimulation parameters. In the second experiment, male rats were randomly assigned into the Sham, BEA, UEA, TEA, and SNS groups to determine the best stimulation method. Lastly, the AA-treated female rats were randomly assigned into the BEA and sham groups to investigate a potential treatment difference between the sexes. Two distinct sets of stimulation parameters were used: Set 1 (100 Hz, 0.5 ms pulse width, 0.1 s ON, 0.4 s OFF, 0.4–3.0 mA current) and Set 2 (25 Hz, 0.5 ms pulse width, 2 s ON, 3 s OFF, 0.4–3.0 mA current).Results (1) The parameter set of 100Hz was found to be most effective in reducing visceral pain. (2) Both acute UEA and TEA effectively relieved visceral pain, whereas acute SNS did not exhibit such an effect. (3) Acute BEA improved visceral pain in both male and female rats.Conclusions These findings suggest that transcutaneous ST36 stimulation is as effective as direct ST36 stimulation and unilateral ST36 stimulation is comparable to bilateral stimulation. Development of a novel therapy using unilateral transcutaneous ST36 stimulation is warranted.

Effect of touch on proprioception: non-invasive trigeminal nerve stimulation suggests general arousal rather than tactile-proprioceptive integration.

Proprioceptive error of estimated fingertip position in two-dimensional space is reduced with the addition of tactile stimulation applied at the fingertip. Tactile input does not disrupt the participants' estimation strategy, as the individual error vector maps maintain their overall structure. This relationship suggests integration of proprioception and tactile information improves proprioceptive estimation, which can also be improved with trained mental focus and attention. Task attention and arousal are physiologically regulated by the reticular activating system (RAS), a brainstem circuit including the locus coeruleus (LC). There is direct and indirect evidence that these structures can be modulated by non-invasive trigeminal nerve stimulation (nTNS), providing an opportunity to examine nTNS effect on the integrative relationship of proprioceptive and tactile information. Fifteen right-handed participants performed a simple right-handed proprioceptive estimation task with tactile feedback (touch) and no tactile (hover) feedback. Participants repeated the task after nTNS administration. Stimulation was delivered for 10 min, and stimulation parameters were 3,000 Hz, 50 μs pulse width, with a mean of 7 mA. Error maps across the workspace are generated using polynomial models of the participants' target responses. Error maps did not demonstrate significant vector direction changes between conditions for any participant, indicating that nTNS does not disrupt spatial proprioception estimation strategies. A linear mixed model regression with nTNS epoch, tactile condition, and the interaction as factors demonstrated that nTNS reduced proprioceptive error under the hover condition only. We argue that nTNS does not disrupt spatial proprioceptive error maps but can improve proprioceptive estimation in the absence of tactile feedback. However, we observe no evidence that nTNS enhances tactile-proprioceptive integration as the touch condition does not exhibit significantly reduced error after nTNS.

High power continuous-wave, Q-switched, and quasi-continuous-wave operation of a diode-pumped Tm,Ho:YAG laser oscillator at 2.09 μm

A high-power diode-pumped 2.09 μm Tm,Ho:YAG laser oscillator with multi-regime operation is demonstrated. In the continuous-wave (CW) regime, it delivers 44.68 W output power with M2 = 3.47, yielding a record-high brightness of 87.57 MW/cm2·sr. In the Q-switched mode, stable laser performance across pulse repetition frequencies (PRFs) from 1 kHz to 4 kHz is achieved. At a PRF of 1 kHz, single pulse energy reaches 22.85 mJ with a pulse width of 443.4 ns and M2 = 3.50. In the quasi-continuous-wave (QCW) operation, a pulse energy of 31.85 mJ is obtained at 200 Hz with a 370 μs pulse width and M2 = 4.49. These pulse energies are the highest reported to date for Tm-Ho co-doped laser oscillators at high PRF. This also marks the first demonstration of a versatile 2 μm laser that can operate at room temperature while delivering high-energy, high-repetition-rate pulses in both nanosecond and microsecond durations within a single device, making it highly appealing for scientific and industrial applications.

Carcass chilling method and electrical stimulation effects on meat quality and color in lamb

Five treatments: Control (C), Pre-evisceration Electrical Stimulation (CES: 15 Hz, 700 mA, 500 μs pulse width, 45 s pulse duration), vascular Rinse & Chill® (RC), CES + RC (ESRC), and RC with ES after evisceration (RCES:15 Hz, 600 mA, 1000 μs, 45 s), were applied to 21 lambs each. After being excised from the carcass, muscles were vacuum packaged and aged (Longissimus lumborum, LL, 3 and 22 d postmortem; Semimembranosus, SM, 3 d postmortem). Temperature, pH, purge, cooking loss, color, Warner-Bratzler Shear Force (WBSF), and consumer sensory evaluations were determined. CES and ESRC resulted in the fastest drop in pH below 6 and ESRC had the lowest likelihood of cold shortening. Sensory tenderness in the ESRC LL was greater than C. No differences in WBSF were found among treatments. RC generally produced lamb with higher lightness (L*). The rapid drop in pH likely was responsible for the increased purge and cooking loss observed. Color was affected by the order of ES and RC application.

A Droplet Generator Using Piezoelectric Ceramics to Impact Metallic Pellets.

Metal micro-droplet ejection technology has attracted attention for its potential applications in the rapid prototyping of micro-metal parts and microelectronic packaging. The current micro-droplet ejection device developed based on this technology faces challenges such as the requirement of a micro-oxygen ejection environment, a complex feeding structure, and high costs. Therefore, a drop-on-demand droplet generator for metallic pellets with impact feed ejection is designed in this paper. This device has a simple and compact structure, does not require a high-cost heat source, and can perform drop-on-demand ejection of metallic pellets in an atmospheric environment. A micro-channel feeding method based on piezoelectric ceramic actuator drives is proposed. A rigid dynamics metallic pellet flight trajectory model is established to analyze the relationships between the driving voltage and the flight trajectory of the pellets. With the help of Fluent to simulate and analyze the melting and ejection processes of the pellets inside the nozzle, the changes in the variable parameters of the flow field in the process of the melting and flight of a single molten drop are studied. The droplet generator produces stable droplets with a 500 µs pulse width and 1100 mm/s initial velocity of the projectile. The simulation results show that a single projectile has to go through three stages including feeding, melting, and ejecting, which take 39.5 ms, 7.85 ms, and 17.65 ms. The total simulation time is 65.0 ms. It is expected that the injection frequency of the metal projectile droplet-generating device will reach 15 Hz.

High-frequency irreversible electroporation ablation for the prostate in Beagle dogs.

Ablation procedures have garnered significant attention as a minimally invasive treatment of prostate diseases. However, the feasibility and safety of applying high-frequency irreversible electroporation (H-FIRE) to ablate the Beagle prostate for benign prostatic hyperplasia (BPH) treatment have not been thoroughly explored, the appropriate range of parameters has not been determined. In order to ensure the feasibility and safety of prostate ablation surgery, we conducted a study using Beagle dogs as subjects to investigate prostate tissue. We utilized a composite steep pulse therapy device to perform ablations on 26 lateral lobes of the prostate in 13 Beagles, employing various parameters for different needle distances. The effectiveness of this device was assessed through the observation of the ablation area, intraoperative muscle tremors, postoperative hematological examination, and gross inspection. The findings of our study revealed that 1,000 to 2,000 v/cm in electric field strength, combined with 5 µs pulse width and pulse number 100, is a safe parameter range for ablation of prostate tissue. At the same time, the large electric field strength (2,000 v/cm) has the best ablation effect with the biggest continuous and thorough ablation area. All parameters of H-FIRE were safe for Beagles. H-FIRE ablation for prostate is safe and effective in dogs, which has the potential to be a useful addition to the range of minimally invasive treatments available for the treatment of BPH against this backdrop of increasing surgical practice.

Leadless pacemaker implantation via the internal jugular vein.

Leadless pacemaker therapy was introduced to overcome lead- and pocket-related complications in conventional transvenous pacemaker systems. Implantation via the femoral vein, however, may not always be feasible. The aim of this study was to evaluate leadless pacemaker implantation using a jugular vein approach and compare it to the standard implantation via the femoral vein. The records of the first consecutive 100 patients undergoing Micra™ leadless pacemaker implantation via the right internal jugular vein from two centres were included in this study. Peri-procedural safety and efficacy of the jugular approach were compared to the first 100 patients using a femoral implantation approach at the University Hospital Zurich. One hundred patients underwent successful implantation of a leadless pacemaker via the internal jugular vein (mean age, 81.18 ± 8.29, 60% males). Mean procedure time was 35.63 ± 10.29 min with a mean fluoroscopy time of 4.66 ± 5.16 min. The device was positioned at the inferior septum in 25 patients, at the high septum in 24 patients, and mid-septum in 51 patients. The mean pacing threshold was 0.56 ± 0.35 V at 0.24 ms pulse width with a sensed amplitude of 10.0 ± 4.4 mV. At follow-up, electrical parameters remained stable in all patients. Compared with femoral implantation, patients undergoing the jugular approach were of similar age and had similar comorbidities. Mean procedure (48.9 ± 21.0 min) and fluoroscopy times (7.7 ± 7.8 min, both P < 0.01) were shorter compared to the femoral approach. Electrical parameters were similar between the two approaches. There were only two complications during jugular veinous implantations (1 pericardial effusion and 1 dislocation), compared to 16 complications using the femoral approach (1 pericardial effusion, 2 femoral artery injuries, and 13 major groin haematomas). The jugular approach may represent a safe and efficient alternative to femoral implantation of the Micra leadless pacemaker.

Electrical stimulation and wet ageing effects on the carcass and meat quality of Australian rangeland goats

Medium voltage electrical stimulation and wet ageing periods effects on the carcasses and meat quality of Australian rangeland goats were investigated. 64 rangeland goats were slaughtered as 2 equal consignments, wherein half were exposed to post-dressing electrical stimulation (300 V, 500 ms pulse width, 45 s) and half were not (control). Carcass and pH decline parameters and glycogen concentration were recorded. At 24 h post-mortem, fresh colour was measured and longissimus lumborum muscles (LL) removed. Within carcass, paired LL were halved and allocated to each of 4 ageing periods (1, 2, 4, or 21 d). There were no significant effects from electric stimulation on LL pH at 18 °C, LL temperature at pH 6, LL pH at 24 h post-mortem, semitendinosus pH at 24 h post-mortem, and LL glycogen concentration. There were no significant interactions between stimulation and ageing period on cooking loss, particle size, purge loss, sarcomere length, shear force, and ultimate pH. Independent to stimulation, shear force, particle size, and cooking values declined as ageing period increased. Purge loss was highest after 21 d of ageing. Colour stability was unaffected by ageing, although all CIE colour coordinates varied across the 74 h total retail display period. There were negative linear relationships found between LL glycogen concentrations and LL temperature at pH 6, ultimate pH, and sarcomere length. These findings suggest there to be little benefit to post-dressing electrical stimulation of rangeland goat carcasses, when applied independent to or in combination with ageing.

Pulsed-field ablation: an alternative ablative method for gastric electrophysiological intervention.

Pulsed-field ablation (PFA) is an emerging ablative technology that has been used successfully to eliminate cardiac arrhythmias. As a nonthermal technique, it has significant benefits over traditional radiofrequency ablation with improved target tissue specificity and reduced risk of adverse events during cardiac applications. We investigated whether PFA is safe for use in the stomach and whether it could modulate gastric slow waves. Female weaner pigs were fasted overnight before anesthesia was induced using tiletamine hydrochloride (50 mg·mL-1) and zolazepam hydrochloride (50 mg·mL-1) and maintained with propofol (Diprivan 2%, 0.2-0.4 mg·kg-1·min-1). Pulsed-field ablation was performed on their gastric serosa in vivo. Adjacent point lesions (n = 2-4) were used to create a linear injury using bipolar pulsed-field ablation consisting of 40 pulses (10 Hz frequency, 0.1 ms pulse width, 1,000 V amplitude). High-resolution electrical mapping defined baseline and postablation gastric slow-wave patterns. A validated five-point scale was used to evaluate tissue damage in hematoxylin and eosin-stained images. Results indicated that PFA successfully induced complete conduction blocks in all cases, with lesions through the entire thickness of the gastric muscle layers. Consistent postablation slow-wave patterns emerged immediately following ablation and persisted over the study period. Pulsed-field ablation induces rapid conduction blocks as a tool to modulate slow-wave patterns, indicating it may be suitable as an alternative to radiofrequency ablation.NEW & NOTEWORTHY Results show that pulsed-field ablation can serve as a gastric slow-wave intervention by preventing slow-wave propagation across the lesion site. Stable conduction blocks were established immediately following energy delivery, faster than previous examples of radiofrequency gastric ablation. Pulsed-field ablation may be an alternative for gastric slow-wave intervention, and further functional and posthealing studies are now warranted.

FgF23 and soluble klotho effects on the myocardium: an ex vivo study

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): German Center for Cardiovascular research Background Fibroblast Growth Factor 23 (FGF23) and soluble Klotho (sKL) play a critical role in mineral homeostasis in the body by acting on the kidney to regulate phosphate levels. Circulating FGF23 levels rise in patients with kidney disease and dysregulation of the FGF23 –sKL- axis is a common phenomenon in uremic cardiomyopathy. Studies have shown that elevated FGF23 levels induce cardiac hypertrophy by targeting cardiac myocytes via FGF receptor isoform 4 (FGFR4), while sKL mitigates these effects and may also exert an independent protective effect on the heart(1,2). Purpose We aimed to study the effects of FGF23 and sKL on myocardial contractility, calcium handling and molecular signaling pathways in the human heart using an ex vivo model of cultured contracting myocardial slices. Methods We obtained human heart slices from explanted hearts from patients undergoing cardiac transplantation at the LMU Klinikum Munich, Germany. The 300 µm thick slices were cultured under continuous stimulation (1 Hz, 3 ms pulse width) with 1 mN preload, and contractile function were recorded continuously. Slices with vehicle, recombinant FGF23 protein (100ug/ml), recombinant sKL protein (200ug/ml) and both FGF23((100ug/ml)+sKL (200ug/ml) were continuously monitored over 10 days. We checked for mRNA expression using RT PCR. Results Treatment of human left ventricular tissue with recombinant FGF23 protein resulted in enhanced mRNA expression of the FGFR4. sKL treatment alone induced downregulation of the FGFR4 gene and mitigated upregulation of FGFR4 in FGF23+ sKL treated slices. Post pause potentiation (PPP), assessed by pausing the stimulation of the slices for 120s and then measuring the relative height of the first beat after resumption of pacing, is an indirect measure of sarcoplasmic reticulum Ca2+ handling capacity. PPP was reduced in FGF23 treated slices and heightened in the slices with sKL compared to vehicle treated ones, indicating that FGF23 and sKL play a role in intracellular Ca2+ handling. Conclusions sKL and FGF23 have opposite effects on human cardiac muscle with sKL mitigating FGF23-induced upregulation of FGFR4. Furthermore, sKL improves, while FGF23 impairs myocardial calcium handling . As altered calcium handling may also be involved in hypertrophic signaling altered calcium handling may provide a means by which FGF23 promotes and sKL inhibits myocardial hypertrophy. sKL is advocated as a promising candidate in exploring it therapeutic role in FGF23 mediated cardiomyopathy. We intend to advance our understanding of sKL-FGF23signaling mechanisms by combining transcriptomic analysis with functional data in this model of myocardial slice culture.

Leadless pacemaker implantation via the internal jugular vein a promising access for an established intervention

Abstract Background Leadless pacemaker therapy was introduced in 2013 to overcome lead- and pocket-related complications in conventional transvenous pacemaker therapy. These leadless devices are self-contained right ventricular single-chamber pacemakers implanted via a femoral percutaneous approach. However, the femoral route is not always possible due to various reasons. The aim of this analysis is to share our first experience using a jugulary approach for the implantation procedure. Purpose To evaluate safety and feasibility of leadless pacemaker implantation via the internal jugulary vein. Methods The records of the first 34 patients who underwent leadless pacemaker implantation via the right internal jugular venous route at our center were analyzed prospectively. Follow-up period was 3 months. Safety as well as efficacy including electrical parameters of the jugular approach were compared with the data of the first 100 patients who underwent a femoral leadless pacemaker implantation at our center (implanted from 2015-2019). Results Thirty-four patients underwent internal jugular vein leadless pacemaker implantation (mean age, 82.37 ± 7.58, 58.8% males). All leadless pacemakers were implanted successfully. The jugular approach was well tolerated by all patients. Mean procedure time was 33.29 ± 8.81 min with a mean fluoroscopy time of 3.66 ± 2.07 min. The device was positioned at the inferior septum in 11 patients, at the high septum in two and midseptal in 21 patients. The mean pacing threshold was 0.52 ± 0.22 V at 0.24 ms pulse width with a sensed amplitude of 9.13 ± 4.08 mV. There were no complications during the procedure as well as during 3-month follow-up. At follow-up, electrical parameters remained stable in all patients. Conclusion Implantation of a leadless pacemaker via the right internal jugulary vein is a safe and effective alternative to the femoral approach.Patient demographics/device parameterDevice value development over time.

Development of a new J-PARC-made internal antenna for the J-PARC RF-driven H− ion source

We have been conducting the test of a new J-PARC-made internal antenna for the J-PARC RF-driven cesiated H− ion source. During the test of high-density plasma production by the antenna, we monitored the outgassing characteristics of the antenna by measuring the mass spectrum of the source gas and optical emission spectrum of the plasma. It is confirmed that no remarkable impurities were detected from the new antenna. The observed emittances of the H− beam extracted by using the new antenna were similar to those by using the SNS-made antenna. To accelerate the endurance test of the new antenna, we applied the antenna for the high-density plasma production to the 5% duty factor (1 ms pulse width with 50 Hz repetition rate) with the 2 MHz RF input power of approximately 60 kW at the ion source test stand. These values are much higher than those in the J-PARC nominal operation; 0.8 ms pulse width with 25 Hz repetition rate (the duty factor of 2%) with the RF input power of approximately 30 kW. The paper describes the results of the characteristics of the new J-PARC-made antenna.

Threshold Voltage Instability After Double Pulse Test Under Different OFF-State Drain Voltages and ON-State Drain Currents in p-GaN Gate AlGaN/GaN HEMT

This study investigated threshold voltage (VTH) instability in a Schottky p-GaN gate AlGaN/GaN high-electron-mobility transistor (HEMT) by using the double pulse test (DPT) with a 1 μs pulse width in the ON-state and OFF-state. OFF-state drain biases (VDS,OFF) of 100–400 V and ON-state drain currents of ID,ON 1–16 A were applied in the DPT to observe the post-DPT VTH shift. The ON-state currents did not strongly influence the device’s characteristics after the DPT. However, the OFF-state voltages, particularly VDS,OFF = 100 and 200 V, exerted notable effects. A TCAD simulation was conducted to investigate the mechanism underlying the VTH shift after the DPT at various VDS,OFF and ID,ON levels.

Neuronal nitric oxide synthase is the main isoform responsible for 6-nitrodopamine release from mouse isolated vas deferens

Rat and human vas deferens (VD) present basal release 6-nitrodopamine (6-ND), which is significantly reduced when the VD is pre-incubated with the nitric oxide (NO) synthase inhibitor L-NAME, or in the case of the rat, when the VD was obtained from rats chronically treated with L-NAME. 6-Nitrodopamine is considered a major mediator of both rat and human VD contractility. Since the origin of 6-ND is not clear in the VD, here it was investigated the basal release of 6-ND from control, eNOS−/−, nNOS−/− and iNOS−/− mice VD to ascertain which NOS isoform(s) play(s) an essential role in 6-ND biosynthesis in the mouse VD. Euthanasia was performed by isoflurane overdose and both VD were removed and immediately placed in Krebs-Henseleit solution (KHS). The release of 6-ND was measured by LC-MS/MS. To evaluate contractility, the mice VD strips were submitted to EFS (60 V for 20 sec, at 2-16 Hz in square-wave pulses, 0.3 ms pulse width, and 0.1 ms delay), using a Grass S88 stimulator (Astro-Medical, Industrial Park, RI, USA). The tissues were allowed to equilibrate under a resting tension of 10 mN, and the isometric tension was registered using a PowerLab system. Isolated VD from control, nNOS−/−), eNOS−/−, and iNOS−/− mice present basal release of both 6-ND and dopamine, as detected by LC-MS/MS. The basal release of 6-ND from isolated VD of nNOS−/− mice was significantly reduced when compared to that obtained from control mice VD, whereas that of dopamine was significantly increased. The basal release of both 6-ND and dopamine from eNOS−/− mice VD was not different compared to that obtained from control mice VD. The basal release of 6-ND from iNOS−/− mice was significantly increased compared to that observed in control mice VD. Electric-field stimulation (EFS) caused frequency-dependent (2Hz - 32Hz) contractions of the mouse isolated VD. The contractions induced by EFS were significantly decreased in nNOS−/− mouse isolated VD, but unaltered in isolated VD obtained from either eNOS−/− or iNOS−/− mice. The results clearly demonstrate that neuronal nitric oxide synthase is the main isoform responsible for 6-ND synthesis/release from mouse isolated VD. The results obtained with the contractions induced by EFS in the mouse VD further support the concept that 6-ND is a major modulator of VD contractility, since the contractions of the VD was only reduced in tissue obtained from nNOS−/− mice. The reduction in the EFS-induced contractions observed in the vas deferens obtained from nNOS−/− mice could be attributed to the reduction observed in the basal release of 6-ND. This research is supported by the São Paulo Research Foundation (FAPESP). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

H− Ion Source RF Plasma Testing with 13 MHz and 27 MHz at the Spallation Neutron Source (SNS)1

The baseline RF-driven H− ion source configuration at the Spallation Neutron Source (SNS) facility uses a continuous wave (CW) 600 W 13 MHz RF system to ignite and maintain a low-density plasma inside the ion source vacuum chamber. After the continuous low-density 13 MHz plasma has been established, a pulsed (typical 1 ms pulse width and 60 Hz pulse repetition rate) 80 kW 2 MHz RF system is used to increase the plasma density to produce the pulsed H− ion beam. Incremental upgrades and improvements to the SNS ion source systems have resulted in the ability to reliably operate an H− ion source for SNS neutron production run cycles that can last up to four months. Conditions inside the SNS H− ion source evolve throughout a four-month run cycle due to changes in impurity levels, sputtering, and erosion. As the internal ion source conditions change during the run cycle, there can also be changes in plasma stability and the 13 MHz RF power level required to ignite the plasma. This paper presents the preliminary results of testing performed on the SNS Ion Source Test Stand (ISTS) system where we looked at plasma ignition and plasma stability using 27 MHz RF in place of the baseline 13 MHz RF system.

Diaphragm Pacing Elicits Ventilatory Plasticity in a Rodent Model of Spinal Cord Injury

Cervical spinal cord injury (cSCI) often results in respiratory impairments requiring the use of chronic mechanical ventilation (MV). Diaphragm pacing (DP) is an emerging clinical intervention designed to combat the deleterious effects of chronic MV by electrically stimulating the diaphragm muscle to maintain ventilation. Anecdotal clinical evidence suggests a rehabilitative benefit of DP; however, current clinical practice is limited by a lack of controlled investigations. Thus, the purpose of this ongoing study was to determine if daily DP could be used as a rehabilitative tool following cSCI. We hypothesized that following cSCI, DP would 1) induce a long-lasting increase in tidal volume 60 minutes after stimulation, and 2) result in sustained improvements in tidal volume after four days of daily DP in awake, behaving rats. To test these hypotheses, we implanted custom electromyography electrodes in the mid-costal region of the left and right hemidiaphragms of male Sprague-Dawley rats. One week later, all animals received a left C2 hemisection (C2Hx; n=14) and a subset also received a left C4-6 dorsal rhizotomy (n=3). One week after injury, rats received stimulation on the paralyzed hemidiaphragm (biphasic 30Hz, 0.8mA, 80 μs pulse width) in phase with breathing (Pacing n=5, Rhizotomy n=3), or served as controls (n=6). We delivered DP to animals within plethysmography chambers in an intermittent pattern (5 minutes on/5 minutes off) for 1 hour/day over 4 consecutive days. Using whole body plethysmography, we recorded ventilation before, during, and for 60 minutes after to examine the acute effects of DP. Additionally, we measured ventilation during normoxia (21% FiO2) and respiratory challenge (10.5% FiO2, 7% FiCO2) before and after C2Hx, and 24 hours after four days of DP to assess the rehabilitative potential of pacing. DP increased tidal volume (% change from pre-pacing) compared to control animals during stimulation (P =0.021). Animals receiving DP displayed an elevated tidal volume compared to controls for at least 60 minutes after DP (P=0.015). When compared to control animals 24 hours after the completion of the pacing protocol, DP animals displayed an increased tidal volume (mL/breath/100g) during both normoxia (P =0.006) and respiratory challenge (P =0.019). In contrast, animals pre-treated with rhizotomy showed a similar tidal volume (mL/breath/100g) compared to controls (normoxia: P=0.597; respiratory challenge: P=0.191), suggesting that DP-induced ventilatory plasticity requires phrenic afferents. Taken together, our data suggest that diaphragm pacing has rehabilitative potential and elicits functional respiratory improvements in rodents following C2Hx. Acknowledgements: This work was supported by funding from the National Institute of Health, grant numbers: R00 HL143207-01 (KAS), UL1TR001436 (TCH) and the APTA Acute Care Physical Therapy Seed Grant (TCH). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Efficacy in Using Urodynamic Parameters of Intravesical Electrical Stimulation for Detrusor Underactivity.

Intravesical electrical stimulation (IVES) remains a controversial therapy for detrusor underactivity (DUA). The purpose of this study is to determine the efficacy of IVES in patients with DUA using pre- and post-IVES urodynamic parameters. Intravesical electrical stimulation procedure is performed using a specific catheter equipped with an internal electrical electrode (cathode). The anode is subsequently affixed to the lower abdomen (suprapubic). Afterward, this specialized catheter is connected to a stimulator. Patients undergo a series of 12 IVES procedures in 1 month with the following predetermined parameters: 20 mA amplitude, 20 Hz frequency, 200 µs pulse width, and 60 minutes stimulation time. Patients underwent a follow-up urodynamic examination 1 month after the IVES series is completed. After IVES, several notable changes were observed, including an increase in Qmax from 7.28 ± 5.24 to 7.29 ± 4.09 (P=.030), a decrease in post-void residual (PVR) from 73.03 ± 43.91 to 62.07 ± 39.10 (P=.005), and an increase in PDet@tQmax from 17.10 ± 12.35 to 18.87 ± 12.47 (P=.009). The aetiologies of DUA were categorized into 3 groups: chronic obstruction (CO), idiopathic (Idio), and neurological disorder (ND). The CO group exhibited significant changes in urodynamic parameters, specifically Qmax (P=.001), PVR (P=.001), and PDet@Qmax (P=.035). Similarly, the idiopathic group also demonstrated improvements in Qmax (P=.008), PVR (P=.037), and PDet@ Qmax (P=.033). Intravesical electrical stimulation has been shown to have a positive effect on patients diagnosed with DUA, particularly those whose DUA is idiopathic or due to chronic obstruction.

Impact of the Reduction Time-Dependent Electrical Conductivity of Graphene Nanoplatelet-Coated Aligned Bombyx mori Silk Scaffolds on Electrically Stimulated Axonal Growth.

Graphene-based nanomaterials, renowned for their outstanding electrical conductivity, have been extensively studied as electroconductive biomaterials (ECBs) for electrically stimulated tissue regeneration. However, using eco-friendly reducing agents like l-ascorbic acid (l-Aa) can result in lower conductive properties in these ECBs, limiting their full potential for smooth charge transfer in living tissues. Moreover, creating a flexible biomaterial scaffold using these materials that accurately mimics a specific tissue microarchitecture, such as nerves, poses additional challenges. To address these issues, this study developed a microfibrous scaffold of Bombyx mori (Bm) silk fibroin uniformly coated with graphene nanoplatelets (GNPs) through a vacuum coating method. The scaffold's electrical conductivity was optimized by varying the reduction period using l-Aa. The research systematically investigated how different reduction periods impact scaffold properties, focusing on electrical conductivity and its significance on electrically stimulated axonal growth in PC12 cells. Results showed that a 48 h reduction significantly increased surface electrical conductivity by 100-1000 times compared to a shorter or no reduction process. l-Aa contributed to stabilizing the reduced GNPs, demonstrated by a slow degradation profile and sustained conductivity even after 60 days in a proteolytic environment. β (III) tubulin immunostaining of PC12 cells on varied silk:GNP scaffolds under pulsed electrical stimulation (ES, 50 Hz frequency, 1 ms pulse width, and amplitudes of 100 and 300 mV/cm) demonstrates accelerated axonal growth on scaffolds exhibiting higher conductivity. This is supported by upregulated intracellular Ca2+ dynamics immediately after ES on the scaffolds with higher conductivity, subjected to a prolonged reduction period. The study showcases a sustainable reduction approach using l-Aa in combination with natural Bm silk fibroin to create a highly conductive, mechanically robust, and stable silk:GNP-based aligned fibrous scaffold. These scaffolds hold promise for functional regeneration in electrically excitable tissues such as nerves, cardiac tissue, and muscles.

Systematic 1 Hz direct electrical stimulation for seizure induction: A reliable method for localizing seizure onset zone and predicting seizure freedom

ObjectiveTo prospectively investigate the utility of seizure induction using systematic 1 Hz stimulation by exploring its concordance with the spontaneous seizure onset zone (SOZ) and relation to surgical outcome; comparison with seizures induced by non-systematic 50 Hz stimulation was attempted as well. MethodsProspective cohort study from 2018 to 2021 with ≥ 1 y post-surgery follow up at Yale New Haven Hospital. With 1 Hz, all or most of the gray matter contacts were stimulated at 1, 5, and 10 mA for 30–60s. With 50 Hz, selected gray matter contacts outside of the medial temporal regions were stimulated at 1–5 mA for 0.5–3s. Stimulation was bipolar, biphasic with 0.3 ms pulse width. The Yale Brain Atlas was used for data visualization. Variables were analyzed using Fisher's exact, χ2, or Mann–Whitney test. ResultsForty-one consecutive patients with refractory epilepsy undergoing intracranial EEG for localization of SOZ were included. Fifty-six percent (23/41) of patients undergoing 1 Hz stimulation had seizures induced, 83% (19/23) habitual (clinically and electrographically). Eighty two percent (23/28) of patients undergoing 50 Hz stimulation had seizures, 65% (15/23) habitual. Stimulation of medial temporal or insular regions with 1 Hz was more likely to induce seizures compared to other regions [15/32 (47%) vs. 2/41 (5%), p < 0.001]. Sixteen patients underwent resection; 11/16 were seizure free at one year and all 11 had habitual seizures induced by 1 Hz; 5/16 were not seizure free at one year and none of those 5 had seizures with 1 Hz (11/11 vs 0/5, p < 0.0001). No patients had convulsions with 1 Hz stimulation, but four did with 50 Hz (0/41 vs. 4/28, p = 0.02). SignificanceInduction of habitual seizures with 1 Hz stimulation can reliably identify the SOZ, correlates with excellent surgical outcome if that area is resected, and may be superior (and safer) than 50 Hz for this purpose. However, seizure induction with 1 Hz was infrequent outside of the medial temporal and insular regions in this study.

Effect of junction temperature on 1.3 µm InAs/GaAs quantum dot lasers directly grown on silicon

Laser junction temperature (Tj) is an essential parameter that directly affects the light power and lifetime of semiconductor lasers. Here, we investigate the effect of Tj on an InAs/GaAs quantum dot (QD) laser grown on a Si(001) substrate. Under 1% low pulsed current (1 µs pulse width and 100 µs period), the pure temperature-induced mode shift rate is 0.084 nm/°C. By increasing the duty cycle and measuring the corresponding mode wavelength shift, the laser’s Tj under the continuous-wave (Tj-CW) mode is predicted to be from 31.1 to 81.6 °C when the injection current increases from 100 to 550 mA. Next, the average thermal resistance is 36.2 °C/W. Moreover, the non-negligible increase in Tj-CW is analyzed to significantly reduce the mean-time-to-failure of Si-based QD laser, especially for cases under high CW injection currents. These results provide an accurate reference for the thermal analysis of silicon-based QD lasers and point the way to high performance on-chip light sources by improving the laser heat accumulation.