Residual Index Research Articles

Economic evaluation of telemonitoring as a follow-up approach for patients with obstructive sleep apnea syndrome starting treatment with continuous positive airway pressure.

Telemonitoring of obstructive sleep apnea patients is increasingly being adopted though its cost-effectiveness evidence base is scanty. This study investigated whether telemonitoring is a cost-effective strategy compared with the standard follow-up in patients with obstructive sleep apnea who are starting continuous positive airway pressure treatment. In total, 167 obstructive sleep apnea patients were randomised into telemonitoring (n = 79) or standard follow-up (n = 88), initiated continuous positive airway pressure treatment, and were followed up for 6 months. The frequencies of healthcare contacts, related costs (in USD 2021 prices), treatment effect and compliance were compared between the follow-up approaches using generalised linear models. The cost effectiveness analysis was conducted from a healthcare perspective and the results presented as cost per avoided extra clinic visit. Additionally, patient satisfaction between the two approaches was explored. The analysis showed no baseline differences. At follow-up, there was no significant difference in treatment compliance, and the mean residual apnea-hypoapnea index. There was no difference in total visits, adjusted incidence rate ratio 0.87 (0.72-1.06). Participants in the telemonitoring arm made eight times more telephone visits, 8.10 (5.04-13.84), and about 73% fewer physical healthcare visits 0.27 (0.20-0.36). This translated into significantly lower total costs for the telemonitoring approach compared with standard follow-up, -192 USD (-346 to -41). The form of follow-up seemed to have no impact on the extent of patient satisfaction. These results demonstrate the telemonitoring of patients with obstructive sleep apnea initiating continuous positive airway pressure treatment as a cost saving strategy and can be argued as a potential worthy investment.

Experimental residual capacity of steel-reinforced concrete-filled steel tubular stub columns after fire exposure

Technological advances in the development of steel–concrete composite structures have led to the introduction of novel types of sections in the sought of higher load-bearing capacities. Particularly for composite columns, the axial capacity of concrete-filled steel tubular (CFST) sections may be enhanced by the introduction of an open steel profile embedded within the concrete infill, forming the so-called steel-reinforced concrete-filled steel tubular (SR-CFST) columns. An important aspect that should be revised, in order to safely use these sections in design, is their performance after a fire. In this experimental program, six SR-CFST stub columns are tested in the post-fire situation. Two series of columns comprising three circular and three square sections with the same steel usage are tested for comparison purposes. The size of the inner steel profile is varied in order to investigate its effect over the post-fire capacity of the columns. The specimens were initially exposed to elevated temperatures inside an electric furnace, and then cooled to ambient temperature; afterwards compressive axial load was applied gradually until failure, to ascertain their residual capacity. The experimental results show the high ductility of the SR-CFST stub columns after heating, with the circular specimens reaching higher post-fire peak loads than their square counterparts. This load increases with the size of the embedded steel profile. The post-fire capacities of the columns are evaluated through the Residual Strength Index, showing similar values for both circular and square SR-CFST columns. Finally, a design equation is proposed to facilitate the evaluation of the post-fire compression resistance of SR-CFST columns, as an extension of the existing room temperature design equation in Eurocode 4 Part 1–2 for CFST columns, accounting for the degradation of the steel and concrete after fire exposure through the corresponding residual factors.

Residual index for measurement configuration optimization in robot kinematic calibration

Residual index for measurement configuration optimization in robot kinematic calibration

Revisiting the maintenance of wakefulness test: from intra-/inter-scorer agreement to normative values in patients treated for obstructive sleep apnea.

The Maintenance of Wakefulness Test is widely used to objectively assess sleepiness and make safety-related decisions, but its interpretation is subjective and normative values remain debated. Our work aimed to determine normative thresholds in non-subjectively sleepy patients with well-treated obstructive sleep apnea, and to assess intra- and inter-scorer variability. We included maintenance of wakefulness tests of 141 consecutive patients with treated obstructive sleep apnea (90% men, mean (SD) age 47.5 (9.2) years, mean (SD) pre-treatment apnea-hypopnea index of 43.8 (20.3) events/h). Sleep onset latencies were independently scored by two experts. Discordant scorings were reviewed to reach a consensus and half of the cohort was double-scored by each scorer. Intra- and inter-scorer variability was assessed using Cohen's kappa for 40, 33, and 19 min mean sleep latency thresholds. Consensual mean sleep latencies were compared between four groups according to subjective sleepiness (Epworth Sleepiness Scale score < versus ≥11) and residual apnea-hypopnea index (< versus ≥15 events/h). In well-treated non-sleepy patients (n = 76), the consensual mean (SD) sleep latency was 38.4 (4.2) min (lower normal limit [mean - 2SD] = 30 min), and 80% of them did not fall asleep. Intra-scorer agreement on mean sleep latency was high but inter-scorer was only fair (Cohen's kappa 0.54 for 33-min threshold, 0.27 for 19-min threshold), resulting in changes in latency category in 4%-12% of patients. A higher sleepiness score but not the residual apnea-hypopnea index was significantly associated with a lower mean sleep latency. Our findings suggest a higher than usually accepted normative threshold (30 min) in this context and emphasise the need for more reproducible scoring approaches.

An insight from energy index characterization to determine the proneness of rockburst for hard rock

The evaluation index and classification criterion of coal bursting liability are often used to evaluate hard rock rockburst proneness. In view of the great difference between the engineering conditions of embedding rocks (hard) and coal seam (softer), the evaluation results of rockburst proneness of hard rock are not accord with the actual situation. Aiming at this problem, rockburst tendency indices were studied by laboratory test in this paper. Based on the analysis of the data, it is concluded that the peak-strength strain energy storage index WETP and residual elastic energy index AEF can reflect the energy and rockburst proneness of hard rock from the elastic energy storage and residual elastic energy. By designing the cyclic loading and unloading test and the uniaxial compression test of rock, the loading rates of the above two kinds of energy indices were determined, and the determination and calculation process of the above two kinds of energy indices were clarified. The experimental results show that the linear elastic energy storage law obtained by cyclic loading and unloading of one sample is not very different from that obtained by multiple samples, both methods can be used for measurement. The peak-strength elastic energy density, pre-peak total input energy density and post-peak failure energy density of rock increase slightly with the strain rate, and the degree of rock fragmentation also has the same trend. The energy index of rock cannot fully reflect the rockburst proneness of rock. Based on the test process and results, in the case of hard rocks, 0.3–1 mm/min could be used for displacement control mode, and 50–140 kN/min should be used for load control mode. Extensometer or instrument sensor can be the strain acquisition methods.

Modelling the developmental trajectories of cognitive reserve in children

AbstractBackgroundCognitive reserve (CR) is thought to protect cognitive ability against neurodegenerative conditions, such as Alzheimer’s disease, or other neurological insults. Because past research has studied the construct extensively in older adult populations, little is known about its development across the lifespan. The current study generated a dynamic CR index based on a modified residual approach utilised successfully in older adults (Reed et al., 2010; Bettcher et al., 2019), and examined its criterion and construct validity in a paediatric cohort comprising children both with and without ADHD.MethodArchived longitudinal data collected across 2011‐2019 from N = 115 children (MAge = 10.48, SDAge = 0.61, n = 72 [63%] male, n = 43 [37%] with ADHD) was obtained from the Murdoch Children’s Research Institute. Static and dynamic CR were operationalised based on residual variance in (change in) fluid intellect (Matrix Reasoning) not explained by demographics (i.e., sex and age) or MRI‐based brain variables (i.e., grey matter volumes, white matter hypointensities [WMH], and hippocampal volumes). This index was subsequently used to predict relevant outcome variables (i.e., sustained attention, working memory, inhibition, word reading, and mathematical computation) to assess criterion validity at baseline and across time, while construct validity was assessed via interaction effects between CR, brain, and baseline/longitudinal outcomes.ResultsApproximately 8% of the variance in fluid intellect was predicted by selected brain and demographics at baseline, with 14% predicted in the longitudinal model. CR at baseline predicted mathematical computation (p&lt;.001), word reading (p = .012), and working memory ability (p&lt;.001) at baseline. CR change only predicted change in word reading ability (p&lt;.001); it was also found to moderate relationships between WMH volume change and word reading trajectory, and between WMH volume change and change in sustained attention performance.ConclusionOur results suggest that CR can be modelled in children using a residual index, but with less validity than in older adults; weak criterion and construct validity were evident, although this should be tempered by the fact that there was minimal variance explained in the residualised variable. An adjusted model optimised for a paediatric cohort will form the basis of further inquiry into the study of CR in a developmental context.

Experimental Investigation on the Influence of Temperature on Coal and Gas Outbursts

With the increasing mining depth, the dynamic disaster of coal and gas outbursts in coal mines has become increasingly prominent, and the bursting liability of coal and rock mass in deep coal seam mining is a necessary condition for the occurrence of rock burst and an important index to measure the failure of coal and rock mass. Thermal damage leads to rock instability and failure, which seriously influences the safe and efficient operation of coal mines. To investigate the effect of thermal damage on the bursting liability of deep coals, the burst tendency index of standard coal was measured after subjecting it to thermal damage at different temperatures. The effects of different thermal damage temperatures on the uniaxial compressive strength index, dynamic failure duration, stiffness ratio index, effective impact energy index, residual energy index change rate, and impact energy velocity of the coal and the influence of the post-peak failure mode of the coal were evaluated. The results revealed that the uniaxial compressive strength of the coal generally decreased with increasing thermal damage temperature. At temperatures above 200 °C, the strength significantly decreased. The comprehensive impact property index indicated that, with increasing thermal impact temperature, the burst tendency first increased up to the peak value at 200 °C and then gradually decreased. With the increase in the thermal damage temperature, the burst tendency decreased and disappeared in the temperature range of 250–300 °C, and the failure mode of the coal changed from brittle failure to brittle plastic failure, and finally ductile failure. The influence of thermal damage on coal bursting liability is studied, which provides a theoretical basis for preventing and controlling coal impact ground pressure hazards.

Neoadjuvant HER2-targeted therapy ± immunotherapy with pembrolizumab (neoHIP): An open label randomized phase II trial.

TPS634 Background: Immune checkpoint inhibition (ICI) is synergistic with HER2-directed therapy in pre-clinical models. Clinically, pembrolizumab (K)-mediated ICI plus HER2-directed therapy with trastuzumab (H) was safe and demonstrated modest activity in H-resistant HER2-positive (HER2+) metastatic breast cancer. Because ICI may confer more robust activity when administered earlier in the course of disease, H and K administered in the curative-intent, treatment-naive setting may allow for de-escalation of cytotoxics; confer life-long, tumor-specific immunity; and ultimately, improve cure rates. Moreover, the synergy of H and K with paclitaxel (T) may overcome the need for dual HER2-blockade with H plus pertuzumab (P). In this randomized, multicenter, phase II, open-label trial the efficacy and safety of neoadjuvant THP vs THP-K vs TH-K are explored. Methods: Patients (pts) ≥18y with previously untreated, stage II-III, HER2+ breast cancer are being randomized and stratified by clinical nodal status (positive vs. negative) and hormone receptor status (positive vs. negative). In arm A, pts received T at 80mg/m2 weekly for 12 weeks, H at 8mg/Kg (loading dose) and then 6mg/Kg every 3 weeks x 3 doses, P at 840 mg (loading dose) and then 420mg/Kg every 3 weeks x 3 doses (THP). In arm B, pts received THP plus K at 200mg every 3 weeks x 4 doses (THP-K). In arm C, pts received TH-K. After enrollment of 22 pts to arm C, a prespecified interim efficacy analysis was conducted, and enrollment to this arm was subsequently terminated. Enrollment to the other arms continues with 32/58 pts enrolled to arm A and 33/58 pts enrolled to arm B as of 2/14/2023. Definitive surgery is 3-6 weeks after the last dose. After surgery, pts are treated per the treating physician’s discretion per local clinical standard. The primary end point is pathologic complete response (pCR) rate in the breast and axilla (ypT0/Tis ypN0). Secondary end points include pCR rate by ypT0ypN0 and ypT0/Tis, residual cancer burden index, event free survival, breast conserving surgery rate, safety and overall survival. Exploratory correlative studies will characterize potential immune biomarkers predictive of efficacy and/or toxicity. Clinical trial information: NCT03747120 .

1023 A Case of Stridor in the Sleep Clinic

Abstract Introduction Multisystem atrophy (MSA) is a neurological degenerative progressive disease affecting multiple systems. These patients are frequently seen in the sleep clinic at specialty centers by sleep neurologists for co-management of sleep disordered breathing and nocturnal respiratory issues. Stridor is a life-threatening condition seen in these patients and requires emergent action. We present a case of MSA with worsening stridor that was missed in the era of virtual telemedicine. Report of case(s) A 53-year-old female with a history of obstructive sleep apnea (OSA) on BiPAP S and multiple system atrophy with parkinsonian subtype presented virtually to sleep clinic for follow up evaluation of her sleep disordered breathing. Six months prior to her visit she was noted to have bilateral vocal fold hypomobility without stridor. At that time, she had a residual apnea-hypopnea index (AHI) of 1.4 with BiPAP-S 16/13 cm H2O and no nocturnal stridor. She was wheelchair bound. She had routine follow up visits with various providers however these were telemedicine visits with her husband doing most of the talking due to weakness. Over the next 5 months she had worsening fatigue and was using BiPAP S during the day intermittently and was referred to the sleep medicine clinic for consideration of supplemental oxygen at night. A repeat overnight oximetry revealed residual oxygen desaturation index (ODI) of 2.5/hr while on BiPAP S. Repeat pulmonary function testing was ordered and patient was recommended to return for immediate in person follow up. When seen in person, patient was noted to have significant stridor which had been ongoing and worsening over last few months including being appreciated while on PAP therapy. Emergent same-day ENT consultation was arranged by sleep providers. Posterior cordectomy was performed shortly thereafter. The patient was scheduled for an AVAPS titration study. Conclusion In cases with progressive neuromuscular disease, stridor may be missed during virtual appointments for a variety of reasons including technical difficulties, or the virtual medium not being sensitive enough to convey stridor. This case highlights the importance of having a high index of suspicion for stridor and impending respiratory failure requiring emergent intervention in patients with neuromuscular disease. Support (if any)

1004 A novel use of adaptive servo ventilation for VNS-induced central sleep apnea in an adolescent with refractory epilepsy

Abstract Introduction Epilepsy is frequently encountered in the pediatric population and some patients are treated by stimulation of the vagus nerve to reduce their seizure frequency. Vagus nerve stimulation (VNS) may induce central sleep apnea. Adaptive servo ventilation is a known treatment option for central sleep apnea in certain adult patients with heart failure and Cheyne-Stokes respiration but is infrequently utilized in the pediatric population. Report of case(s) A 17-year-old male with a history of intractable generalized epilepsy, VNS placement, obstructive sleep apnea (OSA) and central sleep apnea (CSA) presented to our tertiary care center for management of his sleep disordered breathing. Initial management of sleep disordered breathing included CPAP for OSA. After VNS placement, the patient began to have a high residual apnea-hypopnea index on data card download of his CPAP. Polysomnography (PSG) was performed on CPAP and CSA events were noted that correlated with VNS firing. BiPAP was titrated and was unsuccessful in treating the CSA. VNS adjustment did not impact the sleep disordered breathing. Repeat titration with adaptive servo ventilation successfully treated the OSA and CSA. In follow up, the patient is tolerating ASV with improvement in his nocturnal sleep disordered breathing events and his daytime functioning. Conclusion Central sleep apnea can be induced by vagus nerve stimulation. This unique case documents successful treatment of vagus nerve stimulation induced central sleep apnea by adaptive servo ventilation in an adolescent patient. Support (if any)

1009 Surgery: Problem and Solution. Temporomandibular Joint Reconstruction For Treating Obstructive Sleep Apnea After Cosmetic Surgery

Abstract Introduction Orthognathic surgery is often considered for the treatment of obstructive sleep apnea (OSA); however, in some circumstances, specific interventions may precipitate OSA. Report of case(s) A 34 year-old female presented with complaints of snoring and fragmented sleep. She had undergone bimaxillary osteotomy and mandibuloplasty for cosmetic reasons outside of the country in 2019. Prior to the surgery, she was asymptomatic and did not snore. Post operatively, she developed snoring, witnessed apneas, fragmented sleep, and daytime sleepiness. A home sleep apnea test revealed severe obstructive sleep apnea with Respiratory Event Index (REI) 66.4/hr. She was initially treated with Positive Airway Pressure (PAP) while seeking oral surgery consultation. PAP via nasal mask was initially effective with residual Apnea Hypopnea Index (AHI) of 3/hr., but the patient developed difficulty tolerating PAP due to aerophagia, nausea, and eructation, despite limiting pressures to 5-7cm H2O. In 2022, the patient successfully underwent temporomandibular joint (TMJ) reconstruction with total joint prosthesis, TMJ fat grafting, bilateral coronoidectomy, maxillary osteotomy with bone plate and grafting, and partial inferior turbinatectomy. She reported resolution of snoring and significant symptomatic improvement after surgical revision. Repeat home sleep apnea testing 1 month after the surgery revealed REI 0.6/hr. Conclusion This case illustrates the potential for development of OSA following orthognathic surgery. Patients and providers should be aware of this potential complication when pursuing surgical intervention. Support (if any)

1003 Immediate Improvement of Second Degree Heart Block With Effective Treatment of Sleep-Disordered Breathing

Abstract Introduction Cardiac arrhythmia and heart block in particular is commonly found in association with obstructive sleep apnea (OSA). Here we describe real-time responsivity of 2nd degree heart block to treatment of OSA with positive airway pressure (PAP) during a titration study. Report of case(s) Our patient is a 70-year old man without significant cardiovascular disease. He presented with loud snoring and excessive daytime sleepiness. A home sleep apnea test in July 2020 revealed obstructive sleep apnea (respiratory event index 20, oxygen saturation nadir 86%). The patient was treated with auto-adjusting continuous positive airway pressure (APAP) and had symptomatic benefit. His most recent machine data download suggested an elevated residual respiratory event index (REI) of 19.6, 16.5 of which were central. A split-night study was performed to re-characterize the nature of the patient’s obstructive sleep apnea and treatment needs. The baseline portion of the study (AHI 50.8, oxygen saturation nadir 86%) was notable for the presence of frequent 2nd degree heart block (171.0 events/hour of recording). During the titration portion of the study, frequent central sleep apneas emerged with the addition of PAP therapy, consistent with treatment-emergent central sleep apnea. The patient was transitioned to bilevel positive airway pressure spontaneous timed mode (BPAP ST), and a pressure setting of 13/6 cm of water with backup rate of 14 breaths per minute effectively controlled his sleep-disordered breathing. The heart block that had been observed during the baseline portion of the study dramatically improved with the start of BPAP ST. Once the patient’s sleep-disordered breathing was controlled, the patient’s heart block occurred at a rate of only 12.1 events/hour of recording. Conclusion Treatment of sleep apnea has been established to be beneficial for the improvement of cardiac arrhythmias. This case is remarkably instructive in that attainment of an effective treatment setting for sleep-disordered breathing resulted in an almost immediate improvement of heart block. Support (if any)

0915 Comparison of In-person Versus Telehealth Positive Airway Pressure Set Up for Rural Veterans

Abstract Introduction Traditionally, positive airway pressure (PAP) therapy is initiated in a face-to-face visit. This can be a barrier to accessing care for rural Veterans. The COVID-19 pandemic led to the implementation of telehealth PAP set-ups at two large VA sleep centers providing an opportunity to assess the effectiveness of telehealth versus face-to-face PAP initiation in rural Veterans. Methods We performed a retrospective cohort study of rural Veterans (defined by the Rural-Urban Commuting Areas system) to compare outcomes for those who initiated PAP with in-person visits prior to the COVID-19 pandemic to those who initiated PAP with telehealth during the COVID-19 pandemic. We assessed the days of PAP use, hours of PAP use and residual Apnea Hypopnea Index (AHI) at 30-day and 90-day intervals in these two groups. We excluded individuals who received a replacement device, and those who received PAP on or after June 14, 2021, due to a safety recall of PAP devices that may have affected use. Results PAP initiation data was available for 93 individuals, approximately half of whom were initiated on PAP in-person (n=46) and half by telehealth (n=47). There were no significant differences between the in-person and telehealth groups in terms of age, BMI, and AHI, which were 57.23±16 vs 60.67±14 (mean±SD), 31.81±5 vs 31.99±13, and 27.52±23/hr vs 28.85±22/hr respectively. The average number of days per month with PAP use at 30-day and 90-day intervals for in-person vs telehealth set-up was 17.59±11 vs 15.38±12 (p=0.36) and 15.54±13 vs 14.11±14 (p=0.60) respectively. The average number of hours of PAP use at 30-days and 90-days for in-person vs telehealth set-up was 3.25±3 vs 3.11±3 (p=0.82) and 3.15±3 vs 3.07±3 (p=0.90) respectively. The residual AHI at 30-days and 90-days for in-person vs telehealth set-up was 6.61±8/hr vs 5.25±6/hr (p=0.37) and 6.35±8/hr vs 7.68±11/hr (p=0.60) Conclusion In this cohort of rural Veterans, there were no significant differences in outcomes for those who initiated PAP therapy via telehealth when compared to in-person. This supports the feasibility of more widespread implementation of telehealth services for treatment of OSA in order to improve access without compromising patient outcomes. Support (if any) VA OCC FY21 RFA, VAGLAHS GRECC, K24HL143055

Evaluation of pomegranate (Punica granatum) peel for bioaccessibility of polyphenols and prebiotic potential using in vitro model

This research evaluated the bioaccessibility of polyphenols and prebiotic potential of pomegranate peel powder (PPP) on an in vitro model of static gastrointestinal digestion (IVD) combined with a colonic fermentation assay using L. acidophilus. After the IVD, the TPC, TFC, FRAP, DPPH-RSA, and ABTS-RSA were significantly different (p ≤ 0.05) at each digestion phase. Furthermore, the recovery of TPC and TFC after intestinal digestion was profoundly affected (p ≤ 0.05) by salivary or gastric digestion phases by 52.47 and 20.34%, correspondingly. The bioaccessibility values were 34.40 and 30.35%, respectively. Residual intestinal digestibility index (RID) values were 34.36 and 14.16%, respectively. There was a strong correlation (between polyphenolic compounds and antioxidant capacity at each digestion phase. PPP is revealed to be an excellent source of microbial substrates at the level of the large intestine; hence, it is a potential prebiotic. Moreover, PPP is an excellent source of fiber and has high functional properties; thus, it might be utilized in the food industry as a functional ingredient or as a nutraceutical that promotes health.

Experimental investigation and failure characteristics of slit-cut method in rockburst prevention

Rockburst has become one of the most serious threats to the safety of workers, equipment, and excavations in deep underground engineering. However, the prevention of rockburst risk remains an unsolved problem. The slot-cut method was put forward, aiming at the problem of strain burst for tunnel projects. The mechanism and method of slot-cut prevention of delayed rockburst were discussed by laboratory tests, theoretical analysis, and numerical simulation. The mechanical responses, failure patterns and failure indexes of granite specimens were analysed. The rockburst process and deformation evolution law of test specimens with different crack parameters were studied in great detail. Based on the experimental results, a comprehensive discrimination of rockburst proneness was explored. The results demonstrate that the peak stress and damage index of pre-cracked granite initially decreases and subsequently increases with crack angle, and the pre-peak and post-peak elastic modulus with different crack numbers decreases linearly, indicating that a change in the crack number significantly affects the bearing capacity of granite. The failure mode of the granite specimen belongs to the tension-shear composite type. Meanwhile, it was found that both the brittleness index and ejection energy with different cracks show an U-shaped for the pre-cracked granites, confirming that the crack angle of 60° has been found to be the threshold for rockburst proneness. Ultimately, the combination of the rockburst energy index describing rock ejection qualitatively and the optimized residual energy index considering elastic energy at post-peak stage quantitatively provides a judgment criteria to comprehensively characterize the rockburst proneness of granite by the slit-cut method. When compared with original index, the results of the comprehensive discrimination exhibited good accuracy. Therefore, the experimental phenomenon and judgment criteria prove that the slit-cut technology can be well applied to the rockburst prevention.

0988 Vagal Nerve Stimulation and OSA

Abstract Introduction We present a case of obstructive sleep apnea (OSA) worsened by implantation of a vagal nerve stimulator (VNS). A 22-year-old M with PMH of autism and refractory epilepsy s/p VNS implantation was diagnosed with moderate OSA. His parents noted that his sleep-disordered breathing worsened after VNS implantation. He was started on APAP 4-12 cm H2O. Review of adherence data revealed an elevated residual apnea-hypopnea index (AHI) despite nightly usage. PAP titration study was obtained with improvement of AHI on 16 cm H2O. Despite consequent use of determined pressure settings, residual AHI remained elevated. In consultation with the patient’s neurologist, VNS settings were gradually down titrated. Residual AHI improved and remained low as CPAP settings were subsequently weaned. Report of case(s) The vagus nerve is part of the parasympathetic nervous system. Afferent fibers project to cortical regions involved in seizure activity. Vagal nerve activation leads to desynchrony, thereby decreasing seizure activity.3 VNS, an adjunctive non-pharmacologic treatment of refractory epilepsy, consists of a generator with multiple adjustable settings and a lead connected to the left vagus nerve.1 VNS activation, in conjuction with medical therapy, can lead to decreased seizures. However, VNS may cause complications such as vocal cord dysfunction, laryngeal spasm, and dyspnea.2 In this case, VNS was noted to cause OSA due to increased airway obstruction, though the pathophysiological mechanism behind this has not been clearly delineated. 3 Conclusion Based on current evidence of precipitation or worsening OSA with VNS activation, screening and diagnostic testing for OSA in patients under evaluation for VNS placement should be considered. A multidisciplinary approach between Sleep Medicine and Neurology in conjunction with patient goals can lead to a balanced optimization of both epilepsy and OSA management via adjustments of VNS settings, anti-epileptics, and CPAP. Support (if any) 1. VNS therapy epilepsy. Epilepsy Foundation. https://www.epilepsy.com/sites/default/files/atoms/files/516VNS_VNS_FINAL.pdf. December 20, 2022. 2. Ebben MR, Sethi NK, Conte M, Pollak CP, Labar D. Vagus nerve stimulation, sleep apnea, and CPAP titration. J ClinSleepMed. 2008 Oct 15;4(5):471-3. PMID: 18853706. 3. Parhizgar F, Nugent K, Raj R. Obstructive sleep apnea and respiratory complications associated with vagus nerve stimulators. J ClinSleepMed. 2011 Aug 15;7(4):401-7. doi: 10.5664/JCSM.1204. PMID: 21897779.

Investigation of control performance on an absorption/stripping system to remove CO2 achieving clean energy systems

Control study is crucial to ensure smooth operation of any unit operation for clean energy system. There has been growing attention on the utilization of advanced model-based controllers in control studies for CO2 capture. However, such advanced controllers are expensive hence proper performance justifications are needed prior to investment. In the current study, both Proportional-Integral (PI) and Model Predictive Control (MPC) control strategies are investigated and implemented on a pilot scale natural gas CO2 absorption/ stripping system running at higher pressure as well as higher CO2 content, utilizing MATLAB/SIMULINK-Aspen Plus Dynamics interface. The novelty of the work is mainly on the investigation study between the efficiency of the standard PI and MPC controllers for a high pressure and high CO2 content pilot-scale CO2 absorption system. For such high pressure and high CO2 content system, it is imperative to evaluate whether special focus on the control strategy is needed or not. This work simulates and investigates the dynamic behavior and performances of PI and MPC controllers of a high-pressure absorption/stripping system. In addition, a second order model of the system has been developed, which is useful for future studies. Controller performance of the Proportional-Integral (PI) and Model Predictive Controller (MPC) are compared using the features of the responses as well as the residual error index i.e., Integral Absolute Error (IAE). The performance of the PID and MPC controllers based on set point tracking of both the controlled variables for 5% and 15% step changes have been evaluated. Compared to the PI controller, the MPC controller has no peak overshoots, i.e., it shows 10% and 2.86% lower error in the IAE index, and it is capable of handling interactions between the variables of the absorption/stripping system.

Single-Sample Finger Vein Recognition via Competitive and Progressive Sparse Representation

As an emerging biometric technology, finger vein recognition has attracted much attention in recent years. However, single-sample recognition is a practical and longstanding challenge in this field, referring to only one finger vein image per class in the training set. In single-sample finger vein recognition, the illumination variations under low contrast and the lack of information of intra-class variations severely affect the recognition performance. Despite of its high robustness against noise and illumination variations, sparse representation has rarely been explored for single-sample finger vein recognition. Therefore, in this paper, we focus on developing a new approach called Progressive Sparse Representation Classification (PSRC) to address the challenging issue of single-sample finger vein recognition. Firstly, as residual may become too large under the scenario of single-sample finger vein recognition, we propose a progressive strategy for representation refinement of SRC. Secondly, to adaptively optimize progressions, a progressive index called Max Energy Residual Index (MERI) is defined as the guidance. Furthermore, we extend PSRC to bimodal biometrics and propose a Competitive PSRC (C-PSRC) fusion approach. The C-PSRC creates more discriminative fused sample and fusion dictionary by comparing residual errors of different modalities. By comparing with several state-of-the-art methods on three finger vein benchmarks, the superiority of the proposed PSRC and C-PSRC is clearly demonstrated.

Oronasal vs Nasal Masks: The Impact of Mask Type on CPAP Requirement, Pharyngeal Critical Closing Pressure (Pcrit), and Upper Airway Cross-Sectional Areas in Patients With OSA

CPAP delivered via an oronasal mask is associated with lower adherence, higher residual apnea-hypopnea index (AHI), and increased CPAP therapeutic pressure compared with nasal masks. However, the mechanisms underlying the increased pressure requirements are not well understood. How do oronasal masks affect upper airway anatomy and collapsibility? Fourteen patients with OSA underwent a sleep study with both a nasal and oronasal mask, each for one-half of the night (order randomized). CPAP was manually titrated to determine therapeutic pressure. Upper airway collapsibility was assessed using the pharyngeal critical closing pressure (Pcrit) technique. Cine MRI was done to dynamically assess the cross-sectional area of the retroglossal and retropalatal airway throughout the respiratory cycle with each mask interface. Scans were repeated at 4cm H2O and at the nasal and oronasal therapeutic pressures. The oronasal mask was associated with higher therapeutic pressure requirements (ΔM ± SEM;+2.6 ± 0.5; P< .001) and higher Pcrit (+2.4 ± 0.5cm H2O; P= .001) compared with the nasal mask. The change in therapeutic pressure between masks was strongly correlated with the change in Pcrit (r2= 0.73; P= .003). Increasing CPAP increased both the retroglossal and retropalatal airway dimensions across both masks. After controlling for pressure and breath phase, the retropalatal cross-sectional area was moderately larger when using a nasal vsan oronasal mask (+17.2mm2; 95%CI, 6.2-28.2, P< .001) while nasal breathing. Oronasal masks are associated with a more collapsible airway than nasal masks, which likely contributes to the need for a higher therapeutic pressure.

Body posture as a factor determiningsleep quality in patients using non-invasive ventilation.

Sleep quality is influenced by multiple factors. Slow-wave sleep and REM sleep play a key role in homeostasisand are useful indicators of sleep quality. Studies indicate that obstructive sleep apnea (OSA) in the supine position correlates with anatomical changes that exacerbate respiratory events andinfluence the effectiveness of ventilation therapy. This study aimed to evaluate the correlation of body posture with polysomnographic data and adherence of patients using continuous positive airway pressure (CPAP). This was a retrospective study of patients with OSAwho had polysomnography in Rainha Santa Isabel Hospital's sleep laboratory in Torres Novas, Portugal, and met all the inclusion and exclusion criteria. Sociodemographic, polysomnographic, and ventilation therapy variables were collected from that sleep laboratory database between 2015 and 2019. In 30 patients with OSA, residual apnea-hypopnea index (AHIr) and arousal index were lower in the non-supine position compared to the supine position (p value 0.005 and 0.009 respectively). As measures of sleep quality, total sleep time in SWS and REM sleep were greaterin the non-supine position compared to the supine position (p value of 0.002 and 0.010 respectively). The findings suggest that a supine position significantly impairs sleep quality mainly by increasing the number of respiratory events and associated sleepfragmentation. The findings also suggest that thedifference in AHIr between supine and non-supine positions may contribute to non-adherence with CPAPin patients with OSA.