Standard Parameter Values Research Articles

Generalizing Determinacy under Monetary and Fiscal Policy Switches: The Case of the Zero Lower Bound

AbstractIn a fixed‐regime context, it has been established since the work of Leeper (1991) that a determinate and unique equilibrium can be achieved under both monetary dominance (characterized by an active monetary policy and a passive fiscal policy) and fiscal dominance (characterized by an active fiscal policy and a passive monetary policy) regimes yield a determinate unique equilibrium. In this paper, we generalize this well‐established policy‐mix taxonomy to regime‐switching models, and show that switches from monetary dominance to fiscal dominance regimes (and vice versa) render the economy indeterminate for standard parameter values. We apply our results to the important case of the exit from the zero lower bound (ZLB), where monetary policy is inherently passive. Contrary to the fixed‐regime prediction, the economy switching between the ZLB in a fiscally led regime and a monetary dominance regime is robustly indeterminate, making the coordination of agents' beliefs hard for anchoring expected inflation. Finally, we propose a direction toward which the perspective of the fiscal theory of the price level can be made consistent with a unique stable equilibrium.

Government size and the effectiveness of fiscal policy: the bigger the better?

Abstract This study investigates the effect of government size, as measured by the tax revenue to gross domestic product (tax-GDP) ratio, on output responses to increases in government purchases. First, we show that in a standard static neoclassical model, the stimulus effect of fiscal expansion on output increases with the tax-GDP ratio. This finding is quantitatively confirmed using a dynamic neoclassical model with standard functional forms and parameter values. To empirically test the theoretical findings, we analyze the responses of macroeconomic variables to an unanticipated increase in government purchases for 12 Organisation for Economic Cooperation and Development (OECD) countries during 1985–2019 using a state-dependent local projection method. The estimation results reveal that while output responses to an unanticipated fiscal expansion are significantly positive when the tax-GDP ratio is high, they are statistically indistinguishable from zero when the ratio is low. Overall, our findings suggest that fiscal expansion can stimulate output more effectively at high tax rates, unlike the well-known predictions of the traditional Keynesian model.

Fast uncertainty assessment of in-service thrust control for turbofan engines: An equivalent model using Taylor expansion

An equivalent model using Taylor expansion (TEEM) is proposed for a fleet of engines regulated by the industrial baseline controller, aiming at the fast assessment of in-service thrust control under gas path and measurement uncertainties in advance. TEEM is fulfilled initially by the equivalent transformation of measurement uncertainties into engine set-point distribution, followed by a first-order Taylor expansion on the steady-state aero-thermal engine model along the average degradation curve of engine fleets. Simulations are conducted at take-off states on a validated aero-thermal turbofan engine model with publicly available uncertainty statistics on a desktop computer. Results show that the equivalent transformation is successful for both new and degraded engine fleets. Moreover, TEEM can estimate the mean and standard deviation values of key engine control parameters including thrust with the maximum errors of 0.04 % and 3.85 % for new engine fleets, 0.04 % and 6.25 % for degraded engine fleets, respectively, compared to the classic sample-based Monte-Carlo simulations (MCS). Computational time for TEEM and MCS for the tested life cycle are 3,018,564s and 137.52s accordingly, which means 99.995 % simulation time reduction is achieved by TEEM. Hence, the accuracy and efficiency of the proposed model for uncertainty assessment of thrust control of turbofan engines are confirmed.

Numerical simulation of concrete strength based on microstructure and mineral composition analysis using micro-CT and XRD technology

The investigation of mechanical properties in porous materials, such as concrete, has been a significant area of interest in the fields of civil engineering and architecture. Traditional macroscopic mechanical testing methods are limited due to destructive experimental conditions, time-consuming procedures, and the inability to characterize internal structures. To overcome these limitations, researchers have utilized microscopic factors with micro-CT and simulation models. Different simulation methods demand mechanical parameters to effectively model the constituent materials; however, there exists variability in the amount and standard values of these input parameters, which leads to a decrease in the reliability of the obtained results. In order to tackle this issue, a novel approach is proposed, which integrates mineral component analysis using X-ray diffraction (XRD) and establishes coefficients to minimize the number of necessary input parameters. Simulation results demonstrate excellent agreement with experimental measurements, accurately reproducing the stages of elastic deformation, failure, and fracture in the stress-strain curve of concrete. Our findings reveal that changes in the concrete skeletal structure, microstructure, and mineral composition significantly influence compressive strength. Coarse aggregates and high-mechanical-performance minerals, in particular, have a substantial impact. Additionally, the mechanical properties show a significant linear relationship with the strength reduction coefficient of aggregates and concrete cores. In conclusion, the proposed method, combining CT scanning and XRD with FDEM, proves to be a reliable and practical approach for accurately assessing the mechanical properties of concrete. This methodology simplifies the intricate processes associated with the time-intensive parameter calibration, leading to a more efficient parameter allocation procedure. As a result, this method enhances concrete design, promotes a better understanding of parameter impacts, and enables accurate prediction of concrete behavior across diverse scenarios.

Synergistic bifunctionality of ZnO nanowalls: Antibacterial activity and photocatalysis through integrated in silico and in vitro approaches

This research investigation delves into the versatile attributes of ZnO nanowalls, specifically probing into their dual functionality encompassing antibacterial and photocatalytic properties. The synthesis of ZnO was achieved by employing a microwave-mediated co-precipitation technique. The resulting sample underwent thorough characterization through diverse analytical methodologies. X-ray diffraction analysis disclosed the prevalence of the hexagonal wurtzite phase, as confirmed by JCPDS card No. 36–1451, with an average crystallite size determined as 23.48 nm. Tauc plot extrapolation method was applied to the UV absorption spectrum to ascertain the bandgap energy. The ZnO nanostructure morphology, featuring multi-directional nano-walls, was unveiled through scanning electron microscopy (SEM). The BET nitrogen adsorption technique quantified the surface area of the ZnO sample as 6.69 m2/g. In antibacterial evaluation, the in vitro (disk diffusion) method showcased the remarkable efficacy of ZnO against both gram-positive Staphylococcus sp. and gram-negative E. coli bacteria. Complementing these experimental findings, in silico molecular docking studies exposed both nano ZnO ligands with standard and corrected lattice parameter values exhibiting favorable binding energy. Moreover, the synthesized ZnO nanoparticles exhibited remarkable photocatalytic activity, particularly demonstrated in the decolorisation of Azure A and Azure B dyes, following the first-order Langmuir–Hinshelwood kinetic model. The collective findings underscored a synergistic effect within the fabricated ZnO nanoparticles, showcasing their dual prowess in both antibacterial and photocatalytic activities. The observed phenomenon can be chiefly ascribed to the presence of lattice strain and dislocation density. This intriguing dual functionality positions them as promising candidates for potential applications in wastewater treatment.

Exogenous-spatial scale techno-economic methodology for energy application assessment based on levelized cost of electricity: A case study in Norway

Amidst the escalating electricity prices in Norway and Europe, a compelling need arises for alternative and sustainable energy solutions. This study introduces a novel techno-economic method to assess micro-combined heat and power (m-CHP) systems, specifically those powered by Micro Gas Turbines (MGTs). Employing both numerical and experimental analyses, the investigation focuses on the techno-economic viability of MGT-based m-CHP systems fueled by natural gas (NG) and a blend of NG-H2 (23 % Vol.%). A 20-year operational lifespan serves as the basis for calculating the Levelized Cost of Electricity (LCoE) and comparing it with grid-based electricity costs. The technical model relies on 3 kW MGT experiments and numerical system modelling using IPSEPro® software. Economic modelling involves developing a cost model and employing a unique Techno Economic Analysis (TEA)-rooted methodology for LCoE calculation. Through 16 techno-economic scenarios, substantial cost-benefit advantages of m-CHP systems over grid-based electricity are demonstrated, supported by point LCoE values. To address uncertainties, a “Risk and Uncertainty” analysis is conducted using Monte-Carlo Simulation, generating a LCoE distribution. This method incorporates the standard deviations and mean values of key parameters, ensuring economic consistency and reliability with minimal fluctuations. Findings reveal negligible variation from the expected LCoE at 100 % power with NG, providing 98 % accuracy in assessing cost-benefit. The final result yields a Ceq, LCoE of 1.42 Current NOK/kWh (0.13 USD/kWh) and 1.19 constant NOK/kWh (0.11 USD/kWh). In contrast to grid electricity costs (2.54 NOK/kWh (0.24 USD/kWh) with current NOK and 1.78 NOK/kWh (0.17 USD/kWh) with constant NOK, the analysis underscores the significant and sustained cost benefits of m-CHP systems. Moreover, the proposed methodology offers flexibility for transitioning to a “carbon-neutral” operation with hydrogen (H2) as its prices decrease.

Nonuniform sliding-window reconstruction for accelerated dual contrast agent quantification with MR fingerprinting

ObjectiveMR fingerprinting (MRF) can enable preclinical studies of cell tracking by quantifying multiple contrast agents simultaneously, but faster scan times are required for in vivo applications. Sliding window (SW)-MRF is one option for accelerating MRF, but standard implementations are not sufficient to preserve the accuracy of T2*, which is critical for tracking iron-labelled cells in vivo.PurposeTo develop a SW approach to MRF which preserves the T2* accuracy required for accelerated concentration mapping of iron-labelled cells on single-channel preclinical systems.MethodsA nonuniform SW was applied to the MRF sequence and dictionary. Segments of the sequence most sensitive to T2* were subject to a shorter window length, preserving the T2* sensitivity. Phantoms containing iron-labelled CD8+ T cells and gadolinium were used to compare 24× undersampled uniform and nonuniform SW-MRF parameter maps. Dual concentration maps were generated for both uniform and nonuniform MRF and compared.ResultsLin’s concordance correlation coefficient, compared to gold standard parameter values, was much greater for nonuniform SW-MRF than for uniform SW-MRF. A Wilcoxon signed-rank test showed no significant difference between nonuniform SW-MRF and gold standards. Nonuniform SW-MRF outperformed the uniform SW-MRF concentration maps for all parameters, providing a balance between T2* sensitivity of short window lengths, and SNR of longer window lengths.ConclusionsNonuniform SW-MRF improves the accuracy of matching compared to uniform SW-MRF, allowing higher accelerated concentration mapping for preclinical systems.

Individual evolutionary learning in repeated beauty contest games

The Individual Evolutionary Learning (IEL) algorithm was proposed as a portable learning model for games with large strategy spaces. In principle, IEL benchmark simulations could substitute or supplement expensive experiments with human subjects. We evaluate the ability of the IEL model to replicate experimental findings observed in repeated Keynesian Beauty Contest (KBC) games, which have a large strategy space. The IEL specification with standard parameter values is able to capture major dynamical features and differences between treatments in both one-dimensional (Nagel, 1995; Duffy and Nagel, 1997) and two-dimensional (Anufriev et al., 2022b) versions of KBC games. We compare IEL with some other simple learning models and find that it performs relatively better across multiple treatments. We also use IEL to predict behavior in repeated KBC games that have not yet been conducted experimentally.

Determination of the vehicle's carrying capacity taking into account the bearing capacity of the roads

Increasing the efficiency of using the technical parameters of trucks, in order to save resources, remains an urgent task in the operation of vehicles. Maximum vehicle performance is achieved when the vehicle's rated payload capacity is used to its full potential. As practice shows, due to the regulation of weight parameters, the actual carrying capacity, and, consequently, the performance of the vehicle is reduced. The increased load leads to the destruction of the road surface, therefore, for exceeding the standard values of the weight parameters of the car, carriers are subject to administrative punishment in the form of a fine. The actual task is to determine the actual load capacity of the vehicle when the limit value of the axle load according to the regulatory document is ensured. This paper proposes a method for determining the carrying capacity of road trains consisting of a truck tractor and a semi-trailer, taking into account the bearing capacity of highways. When determining the actual mass of the transported cargo, the maximum permissible values of the total mass and axle load of the vehicle were taken into account, which depend on the category of the road, as well as on the design features of the vehicle (type of suspension, wheels, center distance).

Deployment of 5G NR Outdoor-to-Indoor at Midband and mmWave Frequency Implementation in Indonesia's Industrial Area

In the world of telecommunications, there have been significant advancements in broadband access, especially with the introduction of fifth-generation cellular technology, or 5G NR. The presence of 5G may have an impact on performance. This research compares 5G NR network deployment in mid-band at the 3.5 GHz frequency and high-band at 28 GHz frequency in a 5 km2 Pulogadung industrial area. To provide reliable service, link budget calculations were conducted using the downlink outdoor-to-indoor (O2I) and uplink outdoor-to-indoor (O2I) scenarios based online of sight (LOS). The Urban Micro (UMa) propagation model was used for the 3.5 GHz frequency, while the Urban Micro (UMi) model was used for the 28 GHz frequency, both standardized by 3GPP TR 38.901. The calculation results were simulated using the Automatic Site Placement (ASP) feature in Mentum Planet Tools version 7.2.1, which provided recommendations for the new site locations. The simulations showed that the Downlink O2I-LOS scenario, which requires more sites, resulted in stronger signal strength than the Uplink O2I-LOS scenario. The highest signal strength was achieved by the downlink O2I-LOS scenario at the 3.5 GHz frequency, as indicated by an average SS-RSRP value of -91.88 dBm. On the other hand, the lowest signal strength was obtained by the uplink O2I-LOS scenario at the 28 GHz frequency, with an average SS-RSRP value of -98.11 dBm. The difference in predicted 5G SS-RSRP values is influenced by the variation in standard parameter values in the link budget for each frequency.

Deployment of 5G NR Outdoor-to-Indoor at Midband and mmWave Frequency Implementation in Indonesia's Industrial Area

In the world of telecommunications, there have been significant advancements in broadband access, especially with the introduction of fifth-generation cellular technology, or 5G NR. The presence of 5G may have an impact on performance. This research compares 5G NR network deployment in mid-band at the 3.5 GHz frequency and high-band at 28 GHz frequency in a 5 km2 Pulogadung industrial area. To provide reliable service, link budget calculations were conducted using the downlink outdoor-to-indoor (O2I) and uplink outdoor-to-indoor (O2I) scenarios based online of sight (LOS). The Urban Micro (UMa) propagation model was used for the 3.5 GHz frequency, while the Urban Micro (UMi) model was used for the 28 GHz frequency, both standardized by 3GPP TR 38.901. The calculation results were simulated using the Automatic Site Placement (ASP) feature in Mentum Planet Tools version 7.2.1, which provided recommendations for the new site locations. The simulations showed that the Downlink O2I-LOS scenario, which requires more sites, resulted in stronger signal strength than the Uplink O2I-LOS scenario. The highest signal strength was achieved by the downlink O2I-LOS scenario at the 3.5 GHz frequency, as indicated by an average SS-RSRP value of -91.88 dBm. On the other hand, the lowest signal strength was obtained by the uplink O2I-LOS scenario at the 28 GHz frequency, with an average SS-RSRP value of -98.11 dBm. The difference in predicted 5G SS-RSRP values is influenced by the variation in standard parameter values in the link budget for each frequency.

Is cosmic dynamics self-regulating?

In this paper, we discuss a cosmological model for a universe with self-regulating features. We set up the theoretical framework for the model and determine the time evolution of the scale-factor [Formula: see text]. It is shown that such a universe repeatedly goes through alternate periods of matter and dark energy domination. The resulting dynamics oscillates about the would-be ideal time-linear or coasting path, with monotonic expansion. When compared to dynamics of the observed physical universe, the model recovers the observationally established evolutionary features of the latter, from the big bang to the current acceleration, and farther. It suggests a universe that initially emerges from a nonsingular state, associated with a non-exponential acceleration, and which acceleration it exits naturally with matter–energy generation. The model does not have a horizon problem or a flatness problem. It reproduces the observed current values of standard cosmic parameters, including the age [Formula: see text], the current Hubble parameter [Formula: see text] and dark energy [Formula: see text] and matter [Formula: see text] density parameters. The model is falsifiable. It makes predictions that can be tested, as suggested. Finally, we discuss the dimensionless age [Formula: see text] paradox as an example of the model’s ability to address standing puzzles. The findings suggest that dynamics of the physical universe may be self-regulating and predictable.

Open Economy Neoclassical Growth Models and the Role of Life Expectancy

AbstractThis paper applies the Ramsey–Cass–Koopmans (RCK) growth model to an open economy so that, when calibrated with standard parameter values that are commonly used in the small open economy macroeconomic literature, the time paths of the model variables and the speeds of convergence implied by the model conform with empirical evidence. Open-economy versions of the RCK growth model lead to several counterfactual conclusions including: infinite speeds of convergence for physical capital and output; and unbalanced consumption and asset growth. We avoid these undesired results by extending the baseline model with human capital, international credit constraints, and finite horizons. Given its finite-horizons feature, our model allows us to study the growth implications of changes in life expectancy from the perspective of an open economy, as most of the existing theoretical-quantitative literature that focus on the relationship assumes a closed economy. The model predicts that increased life expectancy has positive but diminishing marginal effect on long-run output per capita. We find that, between 1960 and 2018, improvements in average life expectancy at birth raised long-run output per capita in sub-Saharan Africa, the OECD region, and Canada by an estimated 57.49 %, 14.94 %, and 11.58 %, respectively. In addition, if average life expectancy at birth in sub-Saharan African countries converges from its current level to the level in their OECD counterparts, the region’s long-run output per capita will increase by an estimated 22.89 %.

Wake effect parameter calibration with large-scale field operational data using stochastic optimization

This study aims to show the application of stochastic optimization for efficient and robust parameter calibration of engineering wake models. Standard values of the wake effect parameters are generally used to predict power using engineering wake models, but some recent studies have shown that these values do not result in accurate prediction. The proposed approach estimates the wake effect parameters using operational data available from actual wind farms to minimize the prediction error of the wake model by using trust-region optimization. To further improve computational efficiency, we implement stratified adaptive sampling. We employ decision trees to stratify the data and propose two ways of adapting the sampling budget to the constructed strata: budget allocation with dynamic weights and fixed weights. We extend our analysis to determine the functional relationship between the turbulence intensity and wake decay coefficient. Our experiments suggest that wake parameters or a functional relationship between turbulence intensity and wake decay coefficient may need adjustments (from assumed standard values) for a particular wind farm using its operational data to characterize the wake effect better.

Evaluation of Some Haematological Metrics among Smokers in Port Harcourt, Rivers State, Nigeria

Introduction: Smoking is extremely toxic and has had a significant negative impact on society. One of the leading contributors to preventable illness and mortality has been found to be cigarette smoking.
 Aim: The goal of this study is to evaluate a few haematological metrics among smokers in Port Harcourt, Rivers State, and to verify the idea that smoking cigarettes either has a negative or favorable impact on these variables.
 Methodology: In this cross-sectional study, 100 participants between the ages of 20 and 45 were included, 50 of whom were smokers and 50 non-smokers. Venipuncture was used to obtain blood samples from the patients, which was then put into an EDTA vial for a full blood count (FBC) and other haematological analysis. The full blood count and erythrocyte sedimentation rate (ESR) were done using Haemo Auto Analyzer, Model XP-300 KOBE Japan by SYSMEX and the Westergreen method respectively. In order to analyze the data, Graph Prism Pad 6.2 and Microsoft Office Excel 2016 were both used. Using the student's independent t-test, a comparative study of mean and standard deviation values for the various parameters for test and reference ranges was conducted.
 Results: According to the findings, the average age of 50 smokers was 43.6200± 9.7250 years and that for the 50 non-smokers was 42.7800± 6.5440 years, which was statistically insignificant with p valve of 0.6130. Smokers’ haemoglobin level was 14.5080 ± 1.5590 (g/dL) and non-smokers was 12.1340 ± 0.70410 (g/dL). According to statistics, the level of Hb was significantly higher in smokers compared to non-smokers (P<0.0001). In comparison to non-smokers, the RBC count dramatically increased in smokers (P<0.0001) greater than in non-smokers at 5.2550 ± 0.6629 (x1012/L) and 4.6340 ± 0.5530 (x1012/L) respectively. While the total leucocyte count (TLC) in smokers is 8.0500 ± 1.8796 (x109/L), compared to 6.8580 ± 1.2454 (x109/L) in non-smokers. Statistics show that smokers have a higher total leucocyte count than non-smokers (P<0.0002). Smokers' platelet count is 255.7600±61.8351 (x109/L) while non-smokers' is 216.5800±35.5752 (x109/L).The study has statistically shown that smokers' platelet counts rose considerably in comparison to non-smokers (P<0.012).
 Conclusion: It may be concluded that uninterrupted smoking has an undue negative impact on haematological parameters such that increase occur in values of Hb, RBC, TLC and platelets. Significantly, these changes may increase the risk of serious health issues such as heart related defects, hardening of the arteries, Vaquez-Osler disease. It is recommended that smokers have these metrics regularly monitored.

Optimization of hybrid pulse power characterization profile for equivalent circuit model parameter identification of Li-ion battery based on Taguchi method

The modeling of Li-ion batteries is crucial for their stable and efficient operation. The equivalent circuit model (ECM) is the most widely used battery model, for which parameter identification usually involves the hybrid pulse power characteristic (HPPC) test. However, since the HPPC test was designed to determine dynamic power capability of batteries, an investigation of how HPPC parameters affect ECM parameter identification would be reasonable. In this study, the Taguchi method was employed to investigate the effect of four HPPC parameters (positive and negative pulse height, length of pulse and length of relaxation) on ECM's performance under various application conditions (dynamic test, non-dynamic test and quasi-static test). The results show that all four parameters have an effect on ECM performance. For batteries operated only with the predictable charge and discharge patterns, the optimal combination of HPPC parameters values was determined based on Taguchi experiments. If batteries face unpredictable application scenarios, lower positive pulse heights, higher negative pulse heights, shorter pulse lengths and longer relaxation lengths within a certain range should be considered. Compared to established standard parameter values, this makes it possible to build a more accurate general model.

Evaluation of fetal cardiac function in fetal growth restriction via fetal HQ analysis based on two-dimensional STI.

Abnormalities of the fetal cardiovascular system caused by fetal growth restriction (FGR) may lead to adverse outcomes. The fetal cardiac function assessment is of great significance for treatment selection and prognostic evaluation of fetuses with FGR. This study aimed to explore the value of fetal HQ analysis based on speckle tracking imaging (STI) to evaluate the global and regional cardiac function of fetuses with early-onset or late-onset FGR. From June 2020 to November 2022, 30 pregnant women with early-onset FGR (21-38 gestational weeks) and 30 pregnant women with late-onset FGR (21-38 gestational weeks) in the Department of Ultrasound, Shandong Maternal and Child Health Hospital were enrolled. Also, 60 healthy volunteer pregnant women were enrolled as two control groups according to the principle of matching gestational weeks (21-38 gestational weeks). The fetal cardiac functions, including fetal cardiac global spherical index (GSI), left ventricular ejection fraction (LVEF), fractional area change (FAC) of both ventricles, global longitudinal strain (GLS) of both ventricles, 24-segmental fractional shortening (FS), 24-segmental end-diastolic ventricular diameter (EDD), and 24-segmental spherical index (SI), were assessed using fetal HQ. The standard biological values of fetuses and Doppler blood flow parameters of fetuses and mothers were measured. The estimated fetal weight (EFW) measured by the last prenatal ultrasound was calculated, and the weights of newborns were followed up. Among early FGR, late FGR and total control group, significant differences were found in global cardiac indexes of right ventricle (RV), left ventricle (LV) and GSI. For the segmental cardiac indexes, there are significant differences in three groups except parameter of LVSI. Compared with the control group at the same gestational week, the Doppler indexes including MCAPI and CPR in both the early-onset FGR group and the late-onset FGR group were significantly different. The intra- and inter-observer correlation coefficients of RV FAC, LV FAC, RV GLS, and LV GLS were good. Further, the intra- and inter-observer variability in FAC and GLS was small, as analyzed using the Bland-Altman scatter plot. Fetal HQ software based on STI showed that FGR affected the global and segmental cardiac function of both ventricles. FGR no matter early-onset or late-onset altered Doppler indexes significantly. The FAC and the GLS had satisfactory repeatability in evaluating fetal cardiac function.

Evaluation and optimization of meshless methods to estimation of the 3D-stress intensity factors in mode I–III for fatigue life prediction cracked shaft under uni and multi-axial cyclic loading

In this research, in order to estimate 3D-Stress Intensity Factors in mode I–III, fatigue crack growth and fatigue life prediction of a cracked shaft under various cyclic loading, meshless methods are evaluated and the most appropriate method is selected. For better results, the Base Functions (BFs) are first identified and their performance and efficiency are compared with each other. In addition, while enriching the BFs in all methods and study the effect of increasing the number of sentences of Polynomial-BFs (m = 4, 7,10) and their Linearity or Quadraticity in the accuracy of calculations, two sets of Extend-Enriched-RBFs including the Multi-Quadrics and Gaussian RBFs are used in MQ-RPIM and EXP-RPIM methods. To optimize the shape parameters in the RPIM method and determine the Penalty Factor in the MLPG method, Uni and Multi-objective PSO algorithm was used. Then, a shaft with an initial semi-elliptic surface crack as a 3D-meshless domain for discretizing the weak differential equations was selected and modeled under a fixed latitude tensile, bending, and torsional cyclic loads. Changing the standard values of the shape parameters and estimating their optimal values by the PSO algorithm and comparison of findings with the results of Experimental, MLPG, PIM, FEM, and XFEM methods, has led to the best answer from the applied methods for calculation of; displacement, strain and stress fields, and the SIFs in Mode I–III. Finally, based on the results of uniaxial cyclic load analysis and selection of the MQ-RPIM method, the Multi-axial Cyclic load analysis has been performed on 3D-domain. During this analysis, the Paris Parametric equation along with the Elliptic equation and Liu’s Virtual Strain Energy (VSE) model was used to estimate the fatigue crack growth and fatigue life prediction of a submersible cracked shaft of a pump used in water pumping stations.

1652. Sulbactam against Acinetobacter baumannii Pneumonia: Pharmacokinetic/Pharmacodynamic Appraisal of Current Dosing Recommendations

Abstract Background Sulbactam (SUL), available in the USA as ampicillin-sulbactam, is a first line treatment for Acinetobacter baumannii infections. SUL is bactericidal against A. baumannii through affinity to penicillin-binding proteins with no synergy upon ampicillin addition. Despite its wide use, SUL dosing has not been standardized for management of A. baumannii infections. Herein, we examined SUL pharmacokinetic/pharmacodynamic (PK/PD) targets against A. baumannii in a neutropenic murine pneumonia model followed by estimation of the probability of target attainment (PTA) across a range of clinical SUL doses. Methods Eight clinical A. baumannii isolates (SUL MICs 1–16 mg/L) were tested. Mice were inoculated intranasally with 107 colony forming units (CFU)/mL bacterial suspensions. Two hours post inoculation, escalating SUL doses (1–200 mg/kg) were administered q8h for 24 h as ampicillin-sulbactam, while control mice received saline. Efficacy was measured as the change in log10 CFU/ lungs at 24 h compared with 0 h controls. PK and ex vivo protein binding of SUL were assessed in infected mice to determine the free systemic exposures of the regimens utilized. The percentages of dosing interval in which the free plasma concentration exceeded the SUL MIC (%fT > MIC) required to achieve 1- and 2-log kill against each isolate were estimated using Hill-equation. Monte Carlo simulations were performed to determine PTA for these endpoints with various clinically-utilized SUL dosing regimens. Mean and standard deviation values for SUL PK parameters were derived from patients with nosocomial pneumonia due to A. baumannii. Results Median (Interquartile range, IQR) %fT > MIC needed for 1-log and 2-log kill at 24 h were 27.36 (19.94 – 35.11) and 48.36 (38.18 – 58.01), respectively. The corresponding PTA following the maximum FDA-approved SUL dose for pneumonia (1g q6h, 0.5 h infusion) and three off-label doses are reported in the table. Conclusion Currently approved dose of SUL for pneumonia (1g q6h, 0.5 h infusion) provides effective exposure against A. baumannii at the current FDA/CLSI susceptibility breakpoint (SUL MIC ≤ 4 mg/L). Higher and/or more frequent SUL dosing provides additional coverage with 3 g q8h extended infusion further enhancing the PK/PD exposure against isolates with SUL MICs up to 16 mg/L. Disclosures Yasmeen Abouelhassan, PhD, Pfizer: spouse salary Joseph L. Kuti, PharmD, Abbvie: Honoraria|bioMeriuex: Advisor/Consultant|bioMeriuex: Grant/Research Support|Contrafect: Grant/Research Support|Entasis: Grant/Research Support|Merck and Co: Grant/Research Support|Roche Diagnostics: Grant/Research Support|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support|Shionogi: Honoraria|Summit: Grant/Research Support David P. Nicolau, PharmD, Shionogi: Grant/Research Support Kamilia Abdelraouf, PhD, Evopoint Biosciences Co., Ltd: Grant/Research Support|Venatorx Pharmaceuticals, Inc.: Grant/Research Support.

MiR-375 and miR-21 as Potential Biomarkers of Prostate Cancer: Comparison of Matching Samples of Plasma and Exosomes

MiR-21 and miR-375 have been reported as dysregulated in prostate cancer (PCa) in multiple previous studies. Still, variable or even opposing data for the expression of these microRNAs in PCa were found, and their potential biomarker properties remain elusive. In an attempt to clarify their significance as PCa biomarkers, as well as to compare different types of specimens as a source of relevant microRNAs, we used plasma and matching plasma-derived exosomes from patients with PCa and patients with benign prostatic hyperplasia (BPH). Plasma and exosomes were obtained from 34 patients with PCa and 34 patients with BPH, and their levels of expression of miR-21 and miR-375 were determined by RT-qPCR. We found no significant difference in the level of expression of these microRNAs in plasma and exosomes between patients with PCa and BPH. The level of exosomal miR-21 was elevated in PCa patients with high serum PSA values, as well as in patients with aggressive PCa, while for plasma samples, the results remained insignificant. For miR-375, we did not find an association with the values of standard prognostic parameters of PCa, nor with cancer aggressiveness. Therefore, our results support the potential prognostic role of exosomal miR-21 expression levels in PCa.