Compliance Variation Research Articles

Abstract WP48: Prescription Rate for Antihyperglycemic Medication With Proven Cardiovascular Benefit at Discharge in Stroke Patients Not Equal Among Payer Sources

Background: Mortality doubles in stroke patients when Diabetes Mellitus (DM) is present. Target: Type 2 Diabetes SM (TT2DM) is an American Heart Association® (AHA) initiative focused on providing evidence-based guideline (EBG) resources to mitigate risk in hospitalized stroke patients with DM. Participating Get With The Guidelines® (GWTG)-Stroke hospitals track EBG data to improve outcomes. TT2DM initiative has10 EBG data elements related to stroke and the DM subpopulation. The measure  Antihyperglycemic Medication with Proven Cardiovascular (CVD) Benefit at Discharge in Stroke Patients with DM (AMPB) has low compliance. Further data analysis was needed. Methods: GWTG®-Stroke DM reports specific to AMPB were reviewed from Jan.1, 2020-Dec. 21, 2022, from 51 Wisconsin Coverdell Stroke hospitals. Analysis comprised of 5,045 patients with a primary diagnosis of stroke and history of DM or newly identified DM in the denominator. The numerator was satisfied when patients were prescribed a GLP-1 Receptor Agonist or SGLT-2 Inhibitor at discharge. Measure compliance was further delineated according to payment source. Payer sources were identified as: self-pay, Medicaid, Medicare, and Private/HMO. Findings: In the specified timeframe, 11.7% of patients received AMPB. Compliance variation exists across payer source. Only 2.3% identified as self-pay were prescribed AMPB at discharge. Differences in compliance rates were 10% for Medicare, 13.5% Medicaid, and 15.3% with private insurance/HMO. Conclusions: Discharge prescription rate for AMPB has low compliance, further variation exists among patient payer sources. Items for consideration are higher cost of medication and thus payer status are driving factors in prescribing rates. Additional barriers may exist as discharge clinicians may not feel DM management is their responsibility, along with existing medication knowledge gaps. Providing EBC requires shared decision making to ensure proper follow up. Engaging a multidisciplinary approach at discharge to verify insurance coverage, alternate cost options, and follow-up needs may enhance compliance. Future considerations are to assess race “within” payer source to gauge if there is disparate care.

Temporal complexity in photoplethysmography and its influence on blood pressure.

Objective: The temporal complexity of photoplethysmography (PPG) provides valuable information about blood pressure (BP). In this study, we aim to interpret the stochastic PPG patterns with a model-based simulation, which may help optimize the BP estimation algorithms. Methods: The classic four-element Windkessel model is adapted in this study to incorporate BP-dependent compliance profiles. Simulations are performed to generate PPG responses to pulse and continuous stimuli at various timescales, aiming to mimic sudden or gradual hemodynamic changes observed in real-life scenarios. To quantify the temporal complexity of PPG, we utilize the Higuchi fractal dimension (HFD) and autocorrelation function (ACF). These measures provide insights into the intricate temporal patterns exhibited by PPG. To validate the simulation results, continuous recordings of BP, PPG, and stroke volume from 40 healthy subjects were used. Results: Pulse simulations showed that central vascular compliance variation during a cardiac cycle, peripheral resistance, and cardiac output (CO) collectively contributed to the time delay, amplitude overshoot, and phase shift of PPG responses. Continuous simulations showed that the PPG complexity could be generated by random stimuli, which were subsequently influenced by the autocorrelation patterns of the stimuli. Importantly, the relationship between complexity and hemodynamics as predicted by our model aligned well with the experimental analysis. HFD and ACF had significant contributions to BP, displaying stability even in the presence of high CO fluctuations. In contrast, morphological features exhibited reduced contribution in unstable hemodynamic conditions. Conclusion: Temporal complexity patterns are essential to single-site PPG-based BP estimation. Understanding the physiological implications of these patterns can aid in the development of algorithms with clear interpretability and optimal structures.

Abstract 273: Prescription Rate For Antihyperglycemic Medication With Proven Cvd Benefit At Discharge In Stroke Patients Not Equal Among Payer Sources

Mortality doubles in stroke patient with diabetes mellitus (DM). Target: Type 2 DiabetesSM (TT2DM) is an American Heart Association (AHA) initiative focused on providing evidence-based guideline (EBG) resources to mitigate risk in hospitalized stroke patients with DM. Get With The Guidelines® (GWTG)- Stroke hospitals track EBG data to improve patient outcomes. TT2DM initiative is comprised of 10 EBG data elements related to stroke and DM subpopulation. The measure Antihyperglycemic Medication with Proven CVD Benefit at Discharge in Stroke Patients with DM has low compliance. Methods: GWTG®-Stroke DM reports reviewed from January 1, 2020-June 30, 2021, from 50 Wisconsin Coverdell Stroke Program hospitals. Analysis of 2554 patients with primary diagnosis of stroke with history of or newly identified DM during hospitalization were in the denominator. Numerator met when patients were prescribed GLP-1 Receptor Agonist or SGLT-2 Inhibitor at discharge. Measure compliance was further delineated according to payment source documented. Patient payer source was identified as: Self-Pay, Medicaid, Medicare, and Private. Findings: In specified timeframe, 7.9% of patients received Antihyperglycemic Medication with Proven CVD Benefit at Discharge. Compliance variation exists across payer source. Differences in compliance rates were 2.2% Self-Pay, 6.4% for Medicare, 7.7% Medicaid, and 12.1% for Private. Conclusions: Discharge prescription rate for antihyperglycemic medication with proven CVD benefit at discharge in stroke patients has low compliance, further variation exists among payor sources. Items for consideration are higher cost of medication and thus payor status are driving factors in prescribing rates. Additional barriers may exist as discharge clinicians may not feel DM management is their responsibility, there may be a medication knowledge gap. Providing EBC requires shared decision making among patients and clinicians to ensure proper follow up. Engaging a multidisciplinary approach at discharge to verify insurance coverage, alternate cost options, and follow up needs may enhance compliance. Future considerations are to assess race “within” payor source to gauge if there is disparate care.

Mixed Mode Cohesive Law of Adhesive Joints

This work presents an experimental method to determine the cohesive law of thin adhesive joints in mixed mode. The proposed method is based on the MMB (Mixed Mode Bending test). The Energy release Rate and Crack Tip Relative Displacement are determined based on a compliance variation data reduction method by processing the global load displacement curve, without monitoring the crack length and the crack tip relative displacement during the test. Representing the energy release rate versus relative displacement the cohesive law is determined by numerical differentiation. The method is validated numerically by virtual tests including the cohesive zone model. The results reveal that the proposed data reduction scheme is suitable to obtain the mixed mode cohesive law using only the load and displacement data obtained from the testing machine, without any external displacement measurement technique and without any assumption of the form of the cohesive law.

Subject-specific compliance control of an upper-limb bilateral robotic system

This paper proposes a new compliance control strategy on a robot-assisted bilateral upper limb rehabilitation system. The robotic compliance regulation was achieved by modifying predefined training trajectories in real time, based on measured human–robot interaction force and human users’ position within subject-specific workspace. Experimental data were collected from healthy subjects, and indicate that human users can follow predefined training trajectories well under real-time compliance variation, with the maximum normalized root mean square error (NRMSE) value no greater than 1.44%. Preliminary findings are encouraging, which demonstrates the availability of the proposed subject-specific compliance adaptation strategy, and the potential with enhanced training safety and efficacy. Future work will consider conducting a direct comparison between a bilateral upper limb rehabilitation device (BULReD)-assisted compliance training with or without subject-specific adaptation on a large sample of participants with upper limb disabilities.

Modeling the viscoelasticity of shale by nanoindentation creep tests

To investigate the viscoelastic behavior of shale, clay-rich and quartz rich shale samples were examined by nanoindentation creep tests. Moreover, the effects of different holding times (0, 15, 60, 120, and 220 s) on the mechanical and viscoelastic properties of the shales were compared. The experimental results show that the shale sample with the shortest holding time has the highest rock hardness and Young's modulus values, and the sample with the longest holding time has the lowest values, reflecting the effect of the creep on mechanical behavior. Contact creep compliance and cut-off time decreased with increasing loading rate. In contrast, an increase in reduced modulus, hardness, displacement variation and contact creep compliance variation during the holding time was noticed. In addition, the measurements were converted into viscoelastic parameters by the three-element Voigt, Burgers, and two-dashpot Kelvin models. All of these three rheological models were able to produce good fits to actual nanoindentation measurements. The two-dashpot Kelvin model provides the results with the highest accuracy, but the standard deviation is the highest, indicating more fitting parameters can induce model instability. The elastic time fitting parameters decrease with increased holding, while the viscous fitting parameters increase with increasing time, indicating that the viscosity increases with increasing time. By using this model, the data from laboratory tests can be extrapolated to predict shale's long-term creep behavior. Comparing to other two models, the regression parameter of two-dashpot Kelvin model is relatively lower. The fitting time constants and the regression parameters calculated by the same models for clay rich sample is relatively lower than that of quartz rich sample, which is all mainly related to the soft clay and kerogen contents. Thus, the utilization of existing creep experimental data for predicting viscous parameters of clay-rich shale with two-dashpot Kelvin model should be careful.

A simple procedure for the determination of the cohesive law in 4-ENF test with consideration of the friction and R-curve effect

The measurement of initiation and propagation fracture toughness is important for characterizing the delamination behavior of composite laminates, especially in the case with distinct R-curve behavior which can be caused by fiber bridging, shear deformation of matrix, etc. Four-Point End Notched Flexure (4-ENF) is one of the widely adopted tests to measure the mode II toughness values, while the friction between the crack surfaces may have a significant impact on the results. In this paper, a simple procedure to determine the cohesive law in 4-ENF test with consideration of the friction and R-curve effect is proposed. Firstly, determining the equivalent crack advance according to the compliance variation of the specimen is performed, without the need for monitoring the crack length during the test. Next, the Energy Release Rate in mode II (GII) and crack sliding displacement (δt) are derived based on the point-friction assumption and beam theory. Finally, the cohesive law is obtained via the J-integral approach. To obtain suitable values of the penalty stiffness and interface strength, the influence of these parameters on the prediction of 4-ENF test is studied. Comparisons of the numerical results and the experimental data show a good correlation. The effect of variation of friction coefficients on derived cohesive stress and initiate energy release rate is discussed as well.

Geometrical analysis of a continuously variable transmission system designed for human-robot interfaces

New robotic systems are placed out of their constrained workspaces in order to work alongside humans. Consequently, these applications call for robots monitoring and regulating physical human-robot interaction. These robots’ mechanical compliance should be varied when they are in physical contact with the human or their changing environments. This compliance variation can be achieved in a variety of ways. However, one common idea is the variation of joint stiffness mechanically, electromechanically or by control. The solution presented in this paper is an electromechanical way of varying the joint stiffness. Among the electromechanical methods for varying the joint stiffness, continuously variable transmission (CVT) systems can be used in human-robot interfaces if a set of design criteria are met. These criteria include backdrivability, independent output position and stiffness variation, shock absorbing and low mass/inertia. In this paper, a novel two-cone CVT design with a double spherical transmission element is introduced by taking into account the abovementioned criteria. Additionally, design parameters are identified via carrying out a geometrical analysis of this new CVT system.

Fatigue damage on CFRP plates under bending by thermographic and UT analysis, aided with FEM-DIC prediction

In this article, a combination of numerical and experimental methodology for delamination evolution analysis on unidirectional CFRP elements under fatigue is suggested. Fiber-reinforced composite structures exhibit continuous damage accumulation with degradation of effective mechanical properties during cyclic HCF loads. Since advanced composites applications are allowed after extensive experimental certification tests, proposed work is based on experimental procedures to better detect and predict damage initiation and growth, monitoring static displacements and strains under 4-points bending by digital image correlation and measuring compliance variation under fatigue. In addition, non-destructive investigation of composite plates is conducted during cycling tests by using infrared thermography and ultrasonic measurements to detect damage location and validate FEM predictions. Experimental results are analyzed and compared, employing also digital image correlation technique; in addition, thermographic and ultrasonic monitoring inspection with Matlab elaborated measurements are implemented to check results for fatigue damage analysis of same specimens.

What the HEC? Physician variation and attainable compliance targets in antiemetic prophylaxis.

74 Background: U.S. National Antiemetic Guidelines recommend upfront triple prophylaxis (NK1 receptor antagonist (RA) + 5HT3 RA + dexamethasone) for patients receiving highly emetogenic chemotherapy (HEC), including carboplatin AUC ≥ 4 per 2017 guidelines. While existing data show gaps in guideline compliance, variation between individual physicians is less studied, and a realistic target compliance rate remains unknown. Methods: In a large electronic health record database (IBM Explorys), we identified HEC courses of therapy initiated from 2012 to 2017. Guideline compliance was defined as triple prophylaxis at chemotherapy initiation. Patient courses for ≥ 7 day cycles of cisplatin or anthracycline + cyclophosphamide (AC), or carboplatin (≥ 14 day cycles as a proxy for AUC ≥ 4) were ascribed to oncologists based on encounter frequency. We then ranked physicians treating ≥ 5 HEC courses and evaluated guideline compliance and individual physician variation. Results: In total, 10,074 HEC courses were identified and attributed to 451 unique physicians. Overall antiemetic guideline compliance with cisplatin and AC averaged 68% and 81% respectively. When ranked by compliance, the top 20% of physicians were 2.5 - 1.5 times as compliant as the bottom 20% (cisplatin 100% vs 40%; AC 100% vs 67%). For cisplatin, 32% of physicians had > 90% compliance; the remaining 68% were evenly distributed from 0 - 90%. For AC, 56% of physicians had > 90% compliance, and another 14% had 80 - 90%; the remaining 30% were evenly distributed. For carboplatin, 62% of physicians had ≤ 10% compliance, and another 17% had 11 - 20%; however, the majority of these data preceded guideline inclusion of carboplatin AUC ≥ 4 as HEC. Rates were independent of course volume per physician. Conclusions: Considerable physician-level variation exists in triple antiemetic prophylaxis guideline adherence for HEC. Hundreds of physicians had > 90% compliance with guidelines, suggesting 90% is a realistic target. However, the majority exhibited substantial gaps in NK1 RA use in HEC, placing patients unnecessarily at risk for CINV. Interventions are needed to bolster triple antiemetic prophylaxis in HEC, perhaps especially for carboplatin.

A novel experimental procedure to determine the cohesive law in ENF tests

This study presents a novel method to determine the mode II cohesive law of unidirectional carbon fiber reinforced polymer laminates, employing the End Notched Flexure (ENF) test.The fracture toughness in mode II (G) and crack shear displacement (Δt) are determined based on a compliance variation data reduction method (BTBR) by processing the global load displacement curve, without monitoring the crack length and the crack shear displacement during the test. The procedure is validated by finite element analysis including cohesive zone modeling. The results of the method are compared to those obtained with the Direct Method, where the fracture toughness is determined based on the rotations of the load introduction points and the crack shear displacement is directly measured. It is concluded that the proposed data reduction scheme is suitable to obtain the mode II cohesive law using only the load and displacement data obtained from the testing machine, without any external displacement measurement technique and without any assumption of the form of the cohesive law.

The Effect of Tax Knowledge, Self Assessment System, and Tax Awareness on Taxpayer Compliance

This research was conducted to examine the influence of tax knowledge, self assessment system and tax awareness on taxpayer compliance in Banda Aceh City. The sampling technique used is simple randaom sampling that is a simple random sampling, so that the obtained sample of 100 respondents. Knowledge taxation, self assessment system and tax awareness both simultaneously and partially significant effect on taxpayer compliance in Banda Aceh City. Variation of taxation knowledge, self assessment system and tax awareness affect the taxpayer compliance variation of 93.1 percent and the rest of 6.9 percent influenced by other variables outside this research model. In improving taxpayer compliance within Banda Aceh City government is required to socialize the importance of taxes for development so that it will create awareness of taxation and public knowledge in paying taxes.

A novel procedure to determine the cohesive law in DCB tests

A novel method is presented for the determination of mode I cohesive law for the characterization of delamination in unidirectional carbon fiber reinforced polymer laminates. The energy release rate as a function of the crack advance is determined based on an analytical approach where the compliance variation of the specimen as crack advances is used in order to obtain the crack length for every pair of load and displacement data. Based on the same analytic approach, the crack tip opening displacement is determined as a function of the equivalent crack advance assuming that the Fracture Process Zone development is analogous to an equivalent crack advance Δa. These measurements are used to compute the Energy Release Rate and crack opening displacement from which a cohesive law is determined by numerical differentiation. This new method provides a simple way to obtain the mode I cohesive law using only the load and displacement data obtained from the testing machine, without any external displacement measurement technique and without any assumption of the form of the cohesive law.

Phase transition behavior and mechanical properties of (1-x)(Bi1/2Na1/2)TiO3-xSrTiO3 lead-free piezoelectric ceramics

Lead-free (1-x)(Bi1/2Na1/2)TiO3–xSrTiO3 (BNST, 0≤x≤0.25) ceramics were prepared by a conventional solid-state reaction. The effect of increasing the concentration of SrTiO3 (ST) on the phase transition behavior was investigated using x-ray diffraction patterns, field-induced polarization, and strain curves. As the ST concentrations increased, a ferroelectric to ergodic relaxor phase transition occurred. At x=0.25, the highest strain was observed despite the piezoelectric charge constant being the lowest, and the ferroelectric and ergodic relaxor phases seemed to coexist. In order to investigate the mechanical properties of BNST ceramics, the resonance and antiresonance frequencies of various vibration modes were obtained, and the various tensors of elastic compliances were subsequently calculated. Because the resonance and antiresonance frequencies of the ergodic relaxor piezoceramics cannot be easily identified due to the absence of a remanent polarization and strain after the removal of the electric field, some tensors of elastic compliance of BNST with x=0.25 were obtained by extrapolation of the compliance variation as a function of ST concentrations.

Influence of rotary axis on tool-workpiece loop compliance for five-axis machine tools

This study investigated the influence of the rotary axis of a 5-axis machine tool on the tool-workpiece compliance. The evaluation focused on the influence of the rotation angle and clamping condition of the B axis on the compliance variation. A method was determined to calculate the tool-workpiece compliance in an arbitrary direction from compliances measured using orthogonal triaxial excitations. Then, the tool-workpiece compliance of a 5-axis machine tool was evaluated and displayed using a color map. The compliance map showed that the magnitude of the compliance varied by up to 40% with changes in the B axis rotation angle and its clamping condition. A drastic change in the negative real part of the compliance was also detected in the compliance map. The results of an experimental modal analysis are used to discuss the cause of the compliance variation. The bending mode of the B axis is an important mode because the change in the bending direction due to B axis rotation has a great influence on the direction dependency of the compliance magnitude and the stability limit. A cutting experiment was conducted to verify the correspondence between the evaluated compliance and the vibrational amplitude in a real cutting process. The compliance variation in the compliance map corresponded to the amplitude variation of the vibration in an end milling process. The compliance map revealed that the vibration synchronized with the passing cycle of cutters was decreased by 80% by unclamping the B axis.

Kinetics of cracks nucleation on materials interface

In this paper the model of cracks nucleation on materials interface is developed. This model is based on the alliance of the bridged crack model and the thermofluctuational strength theory. The using of the bridged crack model allows to consider a zone of weakened bonds on a material interface as a bridged interface crack and the thermofluctuational theory determines the law of bonds rupture along this zone. The bond destruction in the crack bridged zone is modelled by the bonds compliance variation along the crack bridged zone and over time. Numerical calculations were performed for the physical and mechanical parameters of the joint materials and bonds which are used in microelectronics applications. The results of computation are presented and discussed.

Aortic compliance variation in long male distance triathletes: A new insight into the athlete's artery?

To assess cardiac and vascular adaptations in long-distance male triathletes and the influence of an increased training volume on these parameters. Case-control study using long-distance male triathletes (Tri) (n=12) and an age-matched cohort of sedentary volunteers (Ctrl). All participants gave an informed consent and underwent a Cardiovascular Magnetic Resonance imaging (CMR) exam to measure left and right ventricle functional parameters, and aortic parameters (surface, strain, compliance, pulse wave velocity). This exam was repeated in the triathletes' group after an increased training volume of at least 2h/week for six weeks. Compared to control volunteers, triathletes presented at baseline a typical pattern of athlete's heart (higher end-diastolic, end-systolic and stroke volumes index, p≤0.009, and lower cardiac rate, p=0.015) but similar vascular characteristics except a trend towards an enlarged ascending aorta (surface 942±106 vs 812±127mm2, p=0.058). Between the two visits, the triathletes increased their weekly training time from 9.67±2.43 (Tri1) to 12.15±3.01h (Tri2): no modifications were found regarding cardiac parameters, but compliance and distensibility of the ascending aorta increased, from 2.60 to 3.34mm2/mmHg (p=0.028) and from 3.36 to 4.40×10-3mmHg-1 (p=0.048) respectively. Using CMR, we showed that vascular characteristics of the ascending aorta may vary along the sport season in endurance athletes. This remodelling could be considered as a physiological adaptation, but could eventually lead to an adverse vascular remodelling.

Near-threshold fatigue propagation of physically short and long cracks in Titanium alloy

Damage tolerance is today imposed by the regulations to dimension aeronautical turbine critical parts. Thus resistance of these parts to potential anomalies is assessed. It requires to study, besides standard long cracks, the propagation of cracks of little dimension (some tenth of mm for initial length) which can have an atypical behavior consisting in crack propagation at lower stress intensity factor range than the threshold for long crack. In this context, this study is focused on a bimodal Titanium alloy (TA6V) tested at different temperatures: room temperature and 400°C at a low load ratio R of 0.1, which corresponds to loading of manufactured compressor impellers in these materials.Tests are run on compact tension specimens initially pre-cracked at constant applied stress intensity factor range (ΔK) and then cracked to threshold in view of obtaining a long crack of a/W˜0,5. Physically 2D through-thickness short fatigue cracks are created by gradually removing the plastic wake of this long crack in order to obtain a crack length as short as possible (0.1 mm). Next the short crack obtained is propagated in view of getting different thresholds for different crack lengths according to a procedure of load decrease. Crack closure contribution is systematically measured using the compliance variation technique with numerical data acquisition and filtering for accurate detection of the stress intensity factor (SIF) at the crack opening. 2D short crack propagation behavior is compared to long crack behavior with a special attention given to crack closure. The threshold evolution in function of the crack length is investigated using a Kitagawa diagram approach for determining a non-propagation criterion of short cracks.

An automated methodology for mode II delamination tests under fatigue loading based on the real time monitoring of the specimen’s compliance

This work introduces a procedure based on the real time monitoring of the specimen’s compliance for the experimental characterization of the fatigue behaviour of interlaminar cracks in composites. The methodology was applied to a mode II loading in a three-point end notch flexure test. The onset point for fatigue damage was determined with a precision of one cycle by establishing a threshold on the compliance variation from its initial value. On the other hand, the crack growth rate curve was derived from the continuous monitoring of the compliance and an experimental calibration of said compliance. The precision of this methodology allowed the effect of commonly neglected phenomena such as the thermal expansion of the testing system or the friction between the specimen and the fixture, to be unveiled.

Variational methods for phononic calculations

Three fundamental variational principles used for solving elastodynamic eigenvalue problems are studied within the context of elastic wave propagation in periodic composites (phononics). We study the convergence of the eigenvalue problems resulting from the displacement Rayleigh quotient, the stress Rayleigh quotient and the mixed quotient. The convergence rates of the three quotients are found to be related to the continuity and differentiability of the density and compliance variation over the unit cell. In general, the mixed quotient converges faster than both the displacement Rayleigh and the stress Rayleigh quotients, however, there exist special cases where either the displacement Rayleigh or the stress Rayleigh quotient shows the exact same convergence as the mixed-method. We show that all methods converge faster for smoother material property variations, but when density variation is rough, the difference between the mixed quotient and stress Rayleigh quotient is higher and similarly, when compliance variation is rough, the difference between the mixed quotient and displacement Rayleigh quotient is higher. Since eigenvalue problems such as those considered in this paper tend to be highly computationally intensive, it is expected that these results will lead to fast and efficient algorithms in the areas of phononics and photonics.