Total Peak Research Articles

How does flow connection path and vertical spatial layout of LIDs affect urban runoff? A new LID construction method based on refined landuse and hydrologic characterization

The techniques and modeling methods of Low Impact Development (LID, a more decentralized approach that uses or mimics natural processes to mange stormwater), has been extensively studied due to their positive impacts on urban flooding and water environment. Traditional LID modeling has been typically allocated on a plane layout based on rough land use classification and hydrological characterization. As the LIDs cannot be combined in the same space due to modeling restrictions, the LID effects on runoff control are often underestimated. This paper proposed a vertical LID model construction method based on a refined land use classification and improved hydrological characterization. By establishing a flow connection flux in the LID controller calculations, the overflows of different LIDs can be interconnected and transferred for further infiltration, storage and conveyance. Results showed that the refined approach provided more accurate spatial allocation guidance for LIDs, and the obtained catchment outflow was reduced by 25%-34% in comparison to conventional land use classification in a case study in northern China. The vertical construction method allowed a multi-dimensional LID allocation in space and function and achieved a higher control effect on total outflow volume and peak value. The combined LIDs could cope with the rainfall (i.e., no outflow from the LID plots) within the 50-year event, and the total outflow volume was 13–26% lower than the one from the plane layout method.

Optimization of the Imaged cIEF Method for Monitoring the Charge Heterogeneity of Antibody-Maytansine Conjugate.

The aim of this study was to develop a whole-column imaging-detection capillary isoelectric focusing (icIEF) method for the analytical characterization of charge heterogeneity of a novel humanized anti-EphA2 antibody conjugated to a maytansine derivative. In addition to focusing time, sample composition was optimized: pH range, percent of carrier ampholytes, conjugated antibody concentration, and urea concentration. A good separation of charge isoforms was obtained with 4% carrier ampholytes of a large (3-10) and narrow pH range (8-10.5) (1 : 1 ratio), conjugated antibody concentration (0.3-1 mg/ml) with a good linearity (R2: 0.9905), 2 M of urea concentration, and 12 minute for focusing. The optimized icIEF method demonstrated a good interday repeatability with RSD values: <1% (pI), <8% (% peak area), and 7% (total peak areas). The optimized icIEF was useful as an analytical characterization tool to assess the charged isoform profile of a discovery batch of the studied maytansinoid-antibody conjugate in comparison to its naked antibody. It exhibited a large pI range (7.5-9.0), while its naked antibody showed a narrow pI range (8.9-9.0). In the discovery batch of maytansinoid-antibody conjugate, 2% of charge isoforms had the same pI as the pI of naked antibody isoforms.

Charakterisierung von Fermentationsaromen mittels gaschromatographischer Techniken

Charakterisierung von Fermentationsaromen mittels gaschromatographischer Techniken

Pore fractal characteristics of fiber-reinforced backfill based on nuclear magnetic resonance

To investigate the pore fractal characteristics of fiber-reinforced backfill, uniaxial compression tests and nuclear magnetic resonance (NMR) tests were conducted on reinforced backfills with different cement-tailing ratios (1:6, 1:8, and 1:10) and different fiber types (polyacrylonitrile fiber and glass fiber). The relationship between the pore size distribution, elastic modulus, uniaxial compressive strength, and cement-tailings ratio of the backfill was investigated, and the pore fractal dimensions of three types were quantified. The results showed that the peak signal amplitude and total spectral peak area of the fiber-reinforced backfill were highest reduced by 21.2% and 25.3%, respectively, compared with that of the fiber-free backfill. The uniaxial compressive strength and elastic modulus of the backfill specimens decreased with decreasing cement-tailings ratio. The micropore fractal dimension values of the backfill specimens ranged from 0.30 to 1.00, while the mesopore and macropore fractal dimension values were in the range of 2.96 to 3.00. The correlation coefficients of the mesopore and macropore fractal dimensions of the backfill are >0.94, and the fractal dimension of mesopores and macropores was not significantly correlated with the cement-tailings ratio and fiber type. The results can provide a reference for discussing the relationship between the microscopic pore structure and macroscopic physical parameters of fiber-reinforced backfill.

Headspace GC/MS and LC/MS analysis of bioactive compounds from Gossypium barbadense L. stem and assessment of their antimicrobial and cytotoxic activities

ABSTRACT. In line with the global interest and demand in finding sustainable ways to the emerging antimicrobial and cytotoxic activities, our study highlights the unique chemical composition of G. barbadense stem. Petroleum ether extracts were analyzed via headspace-gas chromatography/mass spectrometry (HS-GC/MS) revealing 48 compounds, thirteen major and accounting for 56.29% of total peak areas. By using liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) identify 16 major phenolic compounds from the methanolic extract. Both petroleum ether and methanolic extracts were tested for antibacterial activity against four pathogenic bacterial strains (Escherichia coli ATCC10536, Staphylococcus aureus ATCC6538, Salmonella enterica ATCC 14028, and Pseudomonas aeruginosa ATCC 9027) by using disk diffusion method. The antifungal activity against two fungal strains (Aspergillus niger and Aspergillus fumigatus) was evaluated. The results were compared to the activity of ciprofloxacin as a stander. The in-vitro cytotoxic activity of the methanolic extract showed a potent effect against liver (HEPG2) with IC50 values (18.8±7.4 μg/mL) and moderate activity against colon (HCT116) and breast (MCF7) cancer.&#x0D; &#x0D; KEY WORDS: Gossypium Barbadense L. Stem, Headspace/GC/MS, LC-ESI-MS, Bioactive compounds, Antimicrobial, Cytotoxic activities&#x0D; &#x0D; Bull. Chem. Soc. Ethiop. 2023, 37(4), 1021-1032. &#x0D; DOI: https://dx.doi.org/10.4314/bcse.v37i4.17

Impact of Electric Vehicle Charging Infrastructure on the Electric Load Profile of Power System: The Case of Latvia

The number of electric vehicles (EVs) is increasing rapidly, and charging infrastructure must keep up with that pace. With increasing charging load, a power system must adapt to the increasing power demand. The research question of this study is: what impact of EV charging on electric load profile is depending on the number of EVs and the mix of charging units (slow, medium, fast)? How much of the total power demand of EVs can be supplied from renewables, i.e., wind and solar power, considering the installed capacities of these technologies, and the match between power production and consumption. Energy system modeling on an hourly basis for different scenarios of the mix of charging units, number of EVs, and installed capacities of wind power plants and solar PVs was used as the method. EnergyPLAN software was used as the modeling tool. The results show the total power demand, peak load, and share of EV charging power demand that can be covered by renewable power technologies for Latvia’s power system in the year 2050. The results are obtained for scenarios of different combinations of EV charging units.

Design and implementation of power management system integrated with cooperative systems for an apartment building

The power management system (PMS) for detached houses has been studied for many years; however, the PMS for apartment buildings (APBs) is not fully understood considering the structures of the APBs. Furthermore, electric vehicle (EV) batteries, photovoltaic (PV) generation, and battery energy storage system (BESS) can be used as distributed energy resources. Therefore, this study proposes an integrated PMS that optimizes the power schedules of individual residents, EV batteries, and common facilities (PV power generation and BESS) in APBs considering the time-of-use pricing policy. To develop the proposed system, a two-stage optimization was adopted using a genetic algorithm. For individual households, the first stage had three objectives: electricity cost, peak power, and user comfort. For the APB, the second stage had two objectives: total electricity cost and total peak power. To evaluate the performance of the proposed system, computational experiments were conducted in three cases: 1) unmanaged schedule, 2) conventional system, and 3) proposed system. For 50- and 100-unit APBs, the proposed PMS had lower total electricity costs (53119 JPY, 106150 JPY) and total peak power demands (184 kW, 366 kW) than the total electricity costs (54744 JPY, 109517 JPY) and total peak power demands (214 kW, 423 kW) of the conventional PMS. Based on a case study that used the proposed two-stage system with different weighting factors, the trade-off relationship among the five objectives of the proposed PMS was obtained. These findings suggest that the all-inclusive power scheduling of the APBs can be managed by dividing the comprehensive demand into individual household and common facility power demands, including cooperative systems. These results provide an important opportunity to advance the understanding of integrated PMS and cooperative systems for APBs. Further research is required to establish the dynamic relationships between households and APBs.

Quantitative LC-MS/MS. 1. Impact of Points across a Peak on the Accuracy and Precision of Peak Area Measurements.

The number of points across a chromatographic peak has long been recognized as a key determinant of the accuracy and precision of the measured peak area. In LC-MS-based quantitation experiments in drug discovery and development, the "rule-of-thumb" has been to use 15 or more points. This "rule" is based on the literature describing chromatographic methods where the goal was to achieve the lowest possible imprecision in the measurements, especially when unknown analytes are being detected. Restricting methods to the requirement of at least 15 points across a peak can be detrimental to the development methods that fully optimize the signal-to-noise ratio for the assay using longer dwell times and/or transition summing. This study aims to show that 7 points across the peak for peaks that are 9 s or less wide provide more than sufficient accuracy and precision for drug quantitation studies. Data from simulated Gaussian curves using a sampling interval of 7 points across the peak gave peak area calculations within 1% of the expected total peak area using the Trapezoidal and Riemann rules and 0.6% for the Simpson rule. Low and high concentration samples (n = 5) were assayed using three different LC methods on three different days on two different instruments (API5000 and API5500). The difference in peak area (%ΔPA) and relative standard deviation of the peak areas (%RSD) was less than ∼5%. No significant difference was observed from the data that were obtained from different sampling intervals, different peak widths, different days, different peak sizes, and different instruments. Three core analytical runs were performed on three different days. In each core run, the lower limit of quantitation (LLOQ, n = 5), low quality control (LQC, n = 5), middle quality control (MQC, n = 5), and high-quality control samples (HQC, n = 5) were processed and run simultaneously with a standard curve. The range of the intra- and interday accuracy and precision for 3 core runs was 98.0-105% and 0.9-3.0% for 7 data points and 97.5-105% and 0.8-4.3% for 17 data points, respectively. No significant difference was observed for the different sampling intervals. The results show a sampling interval of 7 points for peaks up to 9 s wide is sufficient to define a peak accurately and precisely for drug quantitation studies in drug discovery and development.

Influence of ethanol content on the detection of volatile components in Huangjiu

Huangjiu (Chinese rice wine) is a traditional Chinese fermented wine with a unique flavor. The components of this wine are complex, and the ethanol content of different Huangjiu preparations varies greatly. In this study, changes in the chromatographic peak areas of the volatile components of Huangjiu samples with different ethanol contents were measured using headspace-gas chromatography (HS-GC). The influence of ethanol on the quantitative detection of different volatile components of Huangjiu at gas-liquid equilibrium was also analyzed. When the ethanol content of Huangjiu was in the range of 10%-19% vol, the peak areas of 16 volatile components (i. e., sec-butanol, n-propanol, isobutanol, n-butanol, isoamyl alcohol, β-phenyl-ethanol, acetaldehyde, isovaleraldehyde, benzaldehyde, ethyl formate, ethyl acetate, isobutyl acetate, isoamyl acetate, ethyl hexanoate, ethyl lactate, and diethyl succinate) were negatively correlated with the ethanol content. Increases in the ethanol content of the liquor changed the gas-liquid equilibrium of most other trace volatile components. In addition, only the peak area of acetal was positively correlated with ethanol content. The content of acetal in Huangjiu was affected by the alcohol content, and its decomposition reaction occurred along with the dilution process. The influence coefficient of ethanol content on the peak area of the above compounds ranged from -12.4% to 4.9%. The vapor pressure of most volatile components decreased with increasing ethanol content, and different components were affected in different ways. Compared with those of other components, the peak areas of methanol, furfural, and acetic acid were less affected by the ethanol content. These components were also affected by other factors, such as ionization and chemical reactions occurring during the dilution process. When different wine samples were adjusted to the same ethanol content, the concentration of volatile components in these samples became proportional to the total chromatographic peak area and the influence of the matrix effect of ethanol on the quantitative analysis was effectively eliminated. Thus, when researchers use pretreatment methods based on the principle of gas-liquid balance to carry out the quantitative detection of flavor components, they should adjust different rice wine samples to the same alcohol content to effectively control the matrix effect caused by differences in ethanol content and achieve accurate quantitative analysis.

Electrochemically Non-Enzymatic Urea Estimation in Human Dialysate Waste Using Indirect NiOOH-Urea Oxidation

Non-enzymatic urea detection in human dialysate offers a sustainable and spontaneous platform for advanced analysis and monitoring. This study investigated urea estimation in dialysate by using an indirect urea oxidation of nickel on nitrogen doped carbon with an incorporation of surface roughness (Rf) and double layer current (Idl). Fascinatingly, the second oxidation peak on (reverse) cathodic scan at 0.42 V vs Ag/AgCl in cyclic voltammetry and the first peak of differential pulse voltammetry (DPV) after background subtraction were evidenced to the exploited NiOOH binding with urea, concurrently with the regeneration of Ni(OH)2. In presence of more urea, the decreasing trends of the oxidation peaks in both techniques were observed and capable of determining urea concentrations in human dialysate. In consideration of actual reaction current, the measured total current after background subtraction in fresh simulated dialysate provides the sensitivity of −5.136 × 10−5 A.mM−1 (R2 = 0.998) and limit of detection of 60.2 μM in 1–5 mM linear range. For validation in patients’ dialysate, the total current peak was normalized by Rf and subtracted from Idl, resulting in excellent urea estimation with recovery percentage between 99.18 and 102.68 in comparison to that of clinical standard, offering future prognostic monitoring and wearable artificial kidney.

Plastic buckling of oil storage tanks under blast loads

This paper deals with the dynamic behavior of cylindrical shells under blast loads, with special reference to plasticity and plastic buckling. Interest in this problem focuses on the response of steel vertical oil storage tanks with a flat roof under a nearby explosion. The problem is modeled using a finite element discretization of the structure, in which the loads are represented by an impulsive pressure which is variable around the circumference. The results for tanks show that, at low pressure levels, there is an elastic shell behavior, and first yield occurs as the peak blast pressure is increased. For subsequent increases of peak pressure, the dimple extends in the area affected by the pressures, so that vertical stripes with plastic material behavior are formed from top to bottom of the shell. For even higher pressures, a global mode develops with large amplitude displacements. The total plastic energy is investigated under increasing peak pressure levels. It is found that a change in slope occurs in total plastic energy versus peak pressure when plasticity spreads in the shell, and this is associated to the development of a plastic buckling mode. Parametric studies show that the main variable affecting the change in behavior of the shell as identified through the total plastic energy depends on the shell thickness and is only marginally affected by the shell height and diameter. These conclusions are valid for squat shells, such as those used in the oil industry, and may not be accurate for taller shells.

Decay resistance of Pterocarpus erinaceus Poir. and the antifungal properties of its extract

The processing residue of Pterocarpus erinaceus was used to obtain an ethanol-extract, whose anti-fungal properties and mode of action was investigated using multi-omics principles and gas chromatography-mass spectrometry. The results showed that the decay resistance of the heartwood of Pterocarpus erinaceus was in Grade I; it showed strong decay resistance. The effective concentration of 70% ethanol extract of the heartwood of Pterocarpus erinaceus was 13.8%. It showed high inhibition against Coriolus versicolor and Gloeophyllum trabeum, and the content of the extract was positively correlated with the diameter of the inhibition zone. Transcriptomics analysis showed there were 93 genes differentially expressed in Gloeophyllum trabeum. Among them, 42 genes were up-regulated and 51 genes were down-regulated. These genes were mainly related to oxidoreductase activity, integral components of the membrane, carbohydrate metabolism, lipid metabolism, and other related Gloeophyllum trabeum life activities. In total, 31 substances were separated and observed using GC-MS, and their peak areas accounted for 91.8% of the total peak area. Of these, 16 substances including ketones, esters, amines, alkanes, olefins and aromatic compounds showed a relatively high content. Ketones accounted for the most abundance at 29.1%. These compounds may represent the main active components of antifungal and decay resistance.

When impervious cover doesn't predict urban runoff: Lessons from distributed overland flow modeling

We used the distributed hydrologic model GSSHA to simulate overland runoff from impervious and semi-pervious (low vegetation) land covers in a 0.3 km2 urban catchment. The model is hypothetical, which allowed us to test alternative land use configurations and better understand the effects of urban heterogeneity. To track the arrival of water to a stormwater basin inlet from distinct parts of the catchment, we applied a conservative solute tracer to portions of the gridded model area, a new application for GSSHA’s ‘contaminant transport’ module. We rearranged the positions of pervious and impervious land uses over the catchment during four storm events and found that the portion of total runoff volume from impervious areas varied from 50 to 75% while the relative proportion of impervious cover remained constant at 54%. We also applied solute to equal-sized zones with different slopes and land uses and found that percent imperviousness did not predict solute mobilization. Furthermore, variation in total runoff volume and peak discharge for different land use arrangements and storm sizes showed that percent imperviousness could not be used to estimate a runoff-rainfall ratio. Fluctuating solute proportions over time suggested that grab samples might not be adequate for capturing average overland runoff chemistry. We quantified factors contributing to non-linearity in rainfall-runoff responses from an urban watershed with stormwater infrastructure and determined that using models to find hotspots for stormwater infiltration and to explore resilience to future storm events can improve design and function of stormwater control measures.

Differential effects of chronotype on physical activity and cognitive performance in older adults.

Chronotypes reflect individuals' preferred activity and sleep patterns (e.g., "morning-types" vs. "evening-types") and are associated with health and physical activity. Less is known about the relationship between chronotype and cognitive health in older adults. It is unclear whether chronotype's influence is driven by sleep timing or disruption. This study explored the relationship between chronotype, physical activity, and cognitive performance in older adults with and without self-reported sleep disorders. Participants were 153 older adults (M = 70.35, SD = 5.89) who wore an Actigraph on the non-dominant wrist for seven days to measure total physical activity, peak physical activity, and chronotype (sleep interval midpoint). We categorized participants as morning-, evening-, and intermediate-chronotypes and assessed cognitive performance in domains of attention, executive function, and verbal memory. MANCOVAs showed patterns of activity across the 24-hour day differed between chronotypes such that morning-types were active earlier and evening-types active later, ps > .001. Total physical activity and average peak activity did not differ between chronotypes, (ps ≥ .117). Timing of peak activity followed expectations (morning-types peaked earliest (p = .019). Evening-types exhibited significantly worse executive function and attention than intermediate-types, p = .008. When excluding participants with sleep disorders, evening-types engaged in significantly less total physical activity than other groups, but cognitive performance did not differ. We found no differences in total or peak physical activity between groups, which is inconsistent with findings from studies in younger samples. This suggests the role of chronotype on physical activity may change with age and points to the potential impact of methodological discrepancies. While evening-types exhibited worse executive function and attention performance, this finding disappeared when participants with sleep disorders were excluded. Sleep dysregulation rather than sleep timing may be driving this difference. Recent trends in physical activity research explore activity patterns across the 24-hour day and acknowledge codependence between different activity types. Our findings suggest chronotype and activity timing may be important as researchers advance this line of research in older adults.

Abstract 1429: C-terminal phosphorylation of p27 promotes cell cycle dependent changes through transcriptional coregulation of cJun and STAT3

Abstract p27 is a cyclin dependent kinase (CDK) inhibitor that binds cyclin-CDKs to arrest cell cycle. p27 undergoes PI3K/AKT-mediated C-terminal phosphorylation that alters its protein-protein interactions and function. Our prior work showed C-terminally phosphorylated p27 (p27pT157pT198) promotes its association with cJun. Genomic profiling showed p27 is co-recruited with cJun to over half of cJun chromatin binding sites to either activate or repress target genes. p27/cJun activated gene targets include TGFB2, and are associated with EMT, and programs that upregulate stem cells and alter cell adhesion and migration. Here, we pursued the hypothesis that cyclic changes in C-terminally phosphorylated p27 abundance govern p27-regulated transcriptional activity across the cell cycle, switching p27 from a corepressor of target genes in G0, to a transactivator upon PI3K/AKT activation in mid-G1. In synchronized NIH3T3 cells, we made the novel observation that p27pT197 phosphorylation is periodic, peaking in mid G1 after peak in Akt activation. Furthermore, phospho-activated cJunpS63, and phosphorylated STAT3 (STAT3pY705) levels are periodic across the cell cycle with maximal presence in mid-G1. cJun is minimally expressed in quiescence, and is strongly upregulated in early G1. While total cJun expression level remains constant at all time points after exiting G0, cJunpS63 rises sharply in G1 and then declines with cell cycle progression. Similarly, while STAT3 levels rise modestly on G0 exit, phosphorylated STAT3pY705 levels show a similar pattern to that of cJun pS63, minimal in quiescence, then increasing in mid G1. Moreover, both STATpY705 and cJunpS63 co-precipitation with total p27 and p27pT197 peak in early G1. Since complex formation is period, the action of p27/cJun/STAT3 on transcriptional regulation might also be periodic. Myc is upregulated early in G1 and is essential for G1 progression. ChIP-PCR indicate recruitment of p27 and H3K27 acetylation at MYC increased after exit from quiescence. RNA-seq of NIH3T3 cells across the cell cycle showed significant change of total transcript profiles very early after G0 exit and are distinct at each time point reflecting different phases of cell cycle. Genes governing ribosome biogenesis and protein synthetic machinery are rapidly upregulated in early G1. DNA replication/repair genes are rapidly downregulated in early G1 but rise with S/G2-M. Ongoing work investigates global target gene selection by p27/STAT3/cJun and their expression across the cell cycle, and will be presented. The potential role of p27-regulated gene expression in the coordinated progression of cells across the cell cycle has not been explored to date and might prove to be critical in cell cycle progression. Citation Format: Amir Bagheri, Seyedeh Fatemeh Razavipour, Madison Sharp, Joyce Slingerland. C-terminal phosphorylation of p27 promotes cell cycle dependent changes through transcriptional coregulation of cJun and STAT3 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1429.

ASSESSMENT OF TIBIOFEMORAL AND ALLOGRAFT LOADING AFTER OSTEOCHONDRAL ALLOGRAFT TRANSPLANTATION USING SHELL GRAFTS

In this study, we aimed to investigate tibiofemoral and allograft loading parameters after OCA transplantation using tibial plateau shell grafts to characterize the clinically relevant biomechanics that may influence joint kinematics and OCA osseointegration after transplantation. The study was designed to test the hypothesis that there are significant changes in joint loading after tibial plateau OCA transplantation that may require unique post-operative rehabilitation regimens in patients to restore balance in the knee joint.Fresh-frozen cadaveric knees (n=6) were thawed and mounted onto a 6 DOF KUKA robot. Specimens were size matched to +2 mm for the medial-to-lateral width of the medial tibial hemiplateaus. Three specimens served as allograft recipient knees and three served as donor knees. Recipient knees were first tested in their native state and then tested with size-matched medial tibial hemiplateau shell grafts (n=3) prepared from the donor knees using custom-cut tab-in-slot and subchondral drilling techniques. Tekscan sensors were placed in the joint spaces to evaluate the loading conditions under 90N biaxial loading at full extension of the knee before and after graft placement. The I-Scan system used in conjunction analyzed the total force, pressure distribution, peak pressure, and center of force within the joint space.Data demonstrated significant difference (p&lt;0.05) in joint space loading after graft implantation compared to controls in both lateral and medial tibial plateaus. The I-Scan pressure mapping system displayed changes in femoral condylar contact points as well.The results demonstrated that joint space loading was significantly different (p&lt;0.05) between all preoperative and postoperative cadaveric specimens. Despite the best efforts to size match grafts, slight differences in the host's joint geometry resulted in shifts of contact areas between the tibial plateau and femoral condyle therefore causing either an increase or decrease in pressure measured by the sensor. This concludes that accuracy in graft size matching is extremely important to restoring close to normal loading across the joint and this can be further ensured through postoperative care customized to the patient after OCA surgery.

PD30-01 USING MACHINE LEARNING TO CLASSIFY PROCEDURE-SPECIFIC SURGICAL EXPERIENCE BASED ON SURGICAL GESTURE RECOGNITION IN A RADICAL PROSTATECTOMY SIMULATION

You have accessJournal of UrologyCME1 Apr 2023PD30-01 USING MACHINE LEARNING TO CLASSIFY PROCEDURE-SPECIFIC SURGICAL EXPERIENCE BASED ON SURGICAL GESTURE RECOGNITION IN A RADICAL PROSTATECTOMY SIMULATION Nathan Schuler, Lauren Shepard, Tyler Holler, Patrick Saba, and Ahmed Ghazi Nathan SchulerNathan Schuler More articles by this author , Lauren ShepardLauren Shepard More articles by this author , Tyler HollerTyler Holler More articles by this author , Patrick SabaPatrick Saba More articles by this author , and Ahmed GhaziAhmed Ghazi More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003316.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Effectiveness of nerve sparing robot assisted radical prostatectomy (NS-RARP) is mainly based on recovery of postoperative erectile function. Previously, robotic kinematic data differentiated surgical expertise in suturing tasks and predicted continence rates. Using a validated realistic NS-RARP simulation with embedded sensors measuring torque on neurovascular bundles (NVB), our objective was to apply machine learning algorithms to classify surgical experience based on pure surgical gesture data inputs. METHODS: 50 certified urologists with average robotic case volumes (RV) of 1206 (range 100 - >5000) completed surveys and a NS-RARP simulation, during which video and force sensor data were collected. Videos were annotated for ten approved individual surgical gestures (e.g., cut, traction etc.) and aggregated based on instrument used and combinations of multiple gestures. Total force, average force, and number of force peak events were calculated. With a total of 33 inputs, output included total/NS-RARP case volume and NVB force data. Data was fit to a Gaussian Mixture model, then separated based on gesture utilization patterns. Tukey’s HSD test was used to determine significance in inter-group comparisons of RV and force metrics. RESULTS: Participants were clustered into 3 groupings based on mean total RV: 14 Super-Users (SU) (2221), 14 High Volume (HV) (1017), and 5 Low Volume (LV) (110) urologists (Figure 1). Significant differences were found between SU and HV for both Robotic case (p=0.03) and RARP volumes (p=0.008). Gesture pattern comparisons showed significant differences between SU vs HV and HV v LV in 64% and 30% of gesture inputs respectively. Force sensor comparisons showed significant differences in Total Force and Force Peak events between SU vs LV (p=0.014; p=0.021) and HV vs LV (p=0.021; p=0.046) groups. No significant differences in forces between SU and HV were found. CONCLUSIONS: This machine learning algorithm successfully categorized surgical experience into caseload and force applied, based solely on gesture inputs within a realistic simulated NS-RARP task. Differences in gestures differentiated HV from SU urologists, alluding to potential for targeted areas of improvement in gesture patterns, even for HV surgeons. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e830 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Nathan Schuler More articles by this author Lauren Shepard More articles by this author Tyler Holler More articles by this author Patrick Saba More articles by this author Ahmed Ghazi More articles by this author Expand All Advertisement PDF downloadLoading ...

Optimum Phase Count in a 5.4-W Multiphase Buck Converter Based on Output Filter Component Energies

This article presents an analysis of low-power, multiphase interleaved buck converters to illustrate the extent to which adding more phases is beneficial for reducing the passive components’ sizes. The analysis focuses on a typical converter application with a wide operating duty cycle range and requires good load transient. It is shown that by restricting the phase current ripple, the theoretical reduction in total inductor peak energy predicted for increased phase numbers is limited. The article assesses the benefit of inductor coupling and presents guidelines for coupling factor selection to avoid steady-state inductance roll-off over the wide input voltage range. Standard printed circuit board (PCB) manufacturing design rules are shown to place a practical phase count limit considering the reduction in total inductor size. PCB integrated, air-core solenoid and spiral inductors are implemented in both single- and two-phase 5.4 W, 20 MHz buck converter prototypes. When compared with single-phase designs, two-phase spiral inductors are 44% smaller, and the two-phase solenoid has a 54% lower loss. The two-phase prototype converter achieves better overall efficiency and peaks at almost 90% at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V_IN</i> = 4.5 V, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V_OUT</i> = 1.8 V, and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">F_SW</i> = 20 MHz.

Distribution Transformer Loading: Probabilistic Modeling and Diversity Factor

For planning purposes, the loading of assets in electric power distribution circuits is often modelled in terms of a diversified load. The temporal and probabilistic nature of the load is a sum of several individual loads of various levels and characteristics. The diversity factor of such circuits is the ratio of the sum of the individual non-simultaneous load asset ratings energized by that circuit to the total peak simultaneous demand. The diversity factor is temporal and probabilistic in nature. In this paper, the probability density of the load factor is described and modelled for power distribution loads. The model used is the ratio of two dependent bivariate normal random variables. The resulting probability density is termed a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ratio density</i> and a recent algebraic formulation of the ratio density is used. The probabilistic model is compared to results obtained by others. The potential impact of electric vehicle charging loads is applied to the sizing of distribution power supply assets using diversity loading strategies for Level 1 and single phase Level 2 EV chargers. The probabilistic method is offered as an added tool to the conventional, fixed diversity factor method in distribution engineering.

Modelling of Electric Bus Operation and Charging Process: Potential Contribution of Local Photovoltaic Production

The transition from diesel to electric buses allows the reduction of greenhouse gas emissions. However, the impacts of charging strategies on the quality of bus services and the utility grid must be assessed to ensure the feasibility of the energy transition in the public transportation sector. This study investigates the performances of different locations and sizes of charging infrastructures by presenting the comprehensive modelling of a bus network. It also estimates the potential benefits of a local photovoltaic (PV) production to reduce negative impacts on the utility grid. The presented approach is used for modelling one urban bus line in Compiègne, France, and simulations are performed for various case studies. The results demonstrate that the proposed method allows analysing the impact of the charging process on the quality of bus services by determining the delays of arrivals. The simulations also show the impacts of charger placement on bus on-board battery capacity, total peak power demand of battery charging, and PV self-consumption ratio. The amount of PV energy used directly to charge buses remains low, although it varies between scenarios. PV energy during winter is not sufficient to fully charge buses; however, it can be enough with additional stationary storage in the summer.