Manufacturer's Specifications Research Articles

CARACTERIZACIÓN DE LAS PROPIEDADES MECÁNICAS DEL ÁCIDO POLILÁCTICO (PLA) EN IMPRESIÓN 3D: PERSPECTIVAS A PARTIR DE TÉCNICAS AVANZADAS DE ANÁLISIS Y ORIENTACIONES DE IMPRESIÓN

This research examines the mechanical characteristics of polylactic acid (PLA) using a variety of experimental approaches, including analyses of printing orientations and the application of advanced methodologies such as digital image correlation (DIC) for accurate assessment of deformation, along with scanning electron microscopy (SEM) to evaluate fracture properties. Tensile strength, flexural, impact strength, compressive and shear strength were characterized in detail, highlighting the critical impact of layer deposition direction. These findings provide valuable information for optimizing orientation selection in specific additive manufacturing contexts, emphasizing the need to address anisotropy in 3D printed materials engineering. Keywords: Polymer; PLA; 3D-print; industrial process; Digital Image Correlation (DIC).

Industrial Assessment of Mudstone Deposits of Gercus Formation as a Raw Material for Bricks Industry in Erbil Governorate, Northern Iraq

This paper evaluates the mudstone deposits' physical, chemical, and mineralogical properties and the possibility of use as a raw material to manufacture building bricks. Four sites are selected from the Gercus Formation in Shaqlawa district and the samples are tested. The mudstone samples are analyzed to define the grain size, Atterberg limits, chemical, physical and mechanical characteristics of the clay bricks. The grain size analysis of the mudstone samples showed they contained a high percentage of clay and silt and a low percentage of sand. The chemical analysis showed that silica (SiO2) was the major component in the mudstones. XRD analysis showed the presence of non-clay minerals i.e. calcite, quartz, albite and clay minerals of illite, palygorskite and chlorite. Raw samples of all studied sites were treated to prepare brick samples without addition, and others with 10% standard sand added. The results showed that the bricks prepared from the B to B10 and C to C10 stations have varying water absorption and compressive strength, while the efflorescence has light salts. All these properties are within the requirements of the Iraqi specification for brick manufacturing. The sample sites A, D, A10, and D10 are not compatible with the Iraqi standard in terms of absorption and compression.

Optimal deflection techniques for flexible and navigablesuction ureteral access sheaths (FANS): a comparative in vitro PEARLS analysis.

Flexible and navigable suctionureteral access sheaths (FANS) have been introduced without current evidence on how to optimize deflection. Aim was to evaluate in vitro deflection angles with 2 different FANS techniques-sheath advancement and ureteroscope deflection; and effects of sheath size-ureteroscope combinations. We evaluated in vitro deflection angles of 10/12Fr, 11/13Fr and 12/14Fr FANS (Hunan Reborn Medical Co. Ltd) with six single-use flexible ureteroscopes (Pusen Uscope 7.5Fr, OTU WiScope 7.5Fr, OTU WiScope 8.6Fr, Innovex EU-scope 8.7Fr, Red Pine RP-U-C12 8.7Fr and Boston Scientific Lithovue 9.5Fr). Two deflection techniques were tested: (1) sheath advancement-advancing the sheath forward over a maximally deflected ureteroscope, and (2) ureteroscope deflection-maximally deflecting the ureteroscope from various starting positions relative to tip of the sheath. Intra and inter-scope comparisons of maximum deflection angles were significantly different (all ANOVA p < 0.01). Largest maximumangles for all ureteroscopes were with the sheath advancement technique (range 218°-277°), and second largest for most scopes using the ureteroscope deflection technique at tip (range 111°-212°), mostly deviating from manufacturer specifications (range 270°-275°). 10/12Fr and 11/13Fr sheath sizes were more flexible than 12/14Fr. Largest angles were with 11/13Fr sheath-OTU8.6Fr/Innovex8.7Fr combinations. Optimal deflection with FANS is achieved using either a sheath advancement technique, or ureteroscope deflection technique at tip. Despite using these optimized techniques, deflection angles specified by manufacturers seem hardly achievable. The sheath advancement technique and 11/13Fr sheath-OTU8.6Fr/Innovex8.7Fr combinations may be better suited for lower pole situations. Urologists should be aware of these differences and apply the findings to their FANS technique.

Positioning errors and accuracy of CNC machine tools

Abstract Computerized numerically controlled (CNC) machine tools are a solid foundation for modern industrial manufacturing. These machines provide linear and angular displacements in three or five axes. The accuracy of moving and positioning the tooltip relative to the work part's surface determines the final product's accuracy. Errors due to machine positioning can be linear or angular or both. This work studies the positioning errors of a vertical turning center CNC machine type. This machine has three axes, two linear X (horizontal) and Z (vertical), and one rotation axis “C”. The travel of the spindle carrying the cutting tool along the X-axis is 1400mm, and the travel of the carriage holding the spindle along the Z-axis is 1300mm divided into six latches. The machine rotary table which carries the work part can rotate 360°. A highly precise laser interferometer system determines the linear positioning errors in both the X and Z axes. The angular positioning errors for the “C” rotation axis are determined accurately by an autocollimator system. The positioning error measurements are carried out based on ISO 230-2 as a measurement standard of positioning deviation, accuracy, and repeatability. The collected error measurements in linear displacements and angular rotation are analyzed, interpreted, and compared with manufacturer specifications and ISO 13041-4 allowable tolerances.&amp;#xD;

Accuracy of the HemoCue® to measure cell-free plasma hemoglobin and detect clinically significant hemolysis.

Monitoring cell-free plasma hemoglobin (PHb) during extracorporeal therapies allows early intervention of significant hemolysis, but timely measurements are often challenging. We thus present an analysis of a rapid benchtop device's ability to detect clinically significant hemolysis (PHb ≥50mg/dL). PHb was measured in 419 plasma samples from 88 pediatric patients undergoing cardiopulmonary bypass via both the benchtop device (HemoCue® Plasma/Low Hb system) and the clinical laboratory at the Children's Hospital of Pittsburgh (reference standards). Values of PHb ≥50mg/dL as measured by the reference standard was defined as the binary outcome of clinically significant hemolysis. Analyses included Pearson correlations, logistic regression, receiver operating characteristic curves, and Bland-Altman. Because the manufacturer specifications identify the measurement range of the HemoCue® system as 30-3000mg/dL, a secondary analysis was completed using PHb ≥30mg/dL. Using reference measurements, 66/88 subjects had at least one PHb level that fell within the range of detection (≥30mg/dL) of the benchtop device and 46/88 had significant hemolysis as defined by PHb ≥50mg/dL. PHb levels ≥30mg/dL largely correlated with measurements made with the benchtop device (r = 0.82, p < .001). The device was able to predict PHb values ≥30mg/dL (AUROC 0.9582) and ≥50mg/dL (AUROC 0.9637). The Bland-Altman demonstrated a mean difference of 7.0mg/dL with <5% outside the 95% limits of agreement. The HemoCue® system is an effective surrogate for more robust laboratory testing to identify clinically significant hemolysis during cardiopulmonary bypass.

Defending and expanding industrial democracy and worker cooperatives in an age of neoliberal globalisation

ABSTRACT Neoliberalism has reinforced inequality, environmental collapse, famine, refugee crises, supply chain vulnerabilities and more. We agree with Gibson-Graham (2006) that the core of the issue for a post-capitalist politics is to overcome the sense of the inevitability of the dominant system of political economy. With this argument in mind, we analyse the diversity, innovativeness, and resilience of two specific manufacturing alternatives to neoliberal capitalism: the Norwegian industrial democracy and the Mondragon Cooperative Experience. The cases show that each example arises from a unique history, environment, and has unique structures. This diversity shows that there are many paths to workplace democracy, such systems are capable of innovation, and they are internationally competitive. Our comparison also reveals that no successful equilibrium is ever static. Scaling (up or out) to secure market share presents a challenge potentially existential for both models. Reviewing their efforts for meeting these challenges conclude our analysis.

Achievement Oriented Leadership Style and Performance of Manufacturing Small and Medium Enterprises (SMEs) in Nairobi County, Kenya

This study sought to examine the influence of achievement oriented leadership (AOL) style on organizational performance of manufacturing SME’s in Nairobi, Kenya. Positivism research philosophy and descriptive correlational research design were used. The target population of interest in the study comprised of managers/owners from 425 SME’s listed members of the Kenya Association of Manufacturers based in Nairobi region. A sample size of 369 managers/owners was derived using stratified random sampling technique. From this, a total of 367 participated in the study, giving a response rate of 99%. Data was collected using self-administered questionnaires. The descriptive statistics covered were mean, standard deviation, skewness and kurtosis while inferential statistics used for data analysis included:-pearson’s correlation, chi-square and binary logistic regression. Binary logistic regression (Cox and Snell R squared) showed that 5.9 % of the probability of organizational performance was explained by achievement oriented leadership style. The parameter estimates indicated that AOL style positively and significantly predicted organizational performance, β= 2.450, p = .000, p &lt; 0.05. Hence, the study rejected the null hypothesis that AOL style does not influence organizational performance in manufacturing SME’s in Nairobi. From the conclusion, AOL style significantly influenced organizational performance in manufacturing SME’s Nairobi, Kenya. The findings provide insights to the owners/managers of manufacturing SME’s on influence of AOL for better performance. This study recommends further research on SME’s from specific manufacturing categories in Kenya, the inclusion of demographic variables and a longitudinal approach to reveal the impact of AOL style on organizational performance over time.

In-suit cemented strategy enables intumescent flame retardant transition from hyper-hydrophilic to hydrophobic and aggregation flame retardant effect simultaneously in polypropylene

To meet the stringent requirements of specific high-end manufacturing applications involving flame retardant polypropylene (PP) materials, it's imperative to overcome the inherent superhydrophilicity of intumescent flame retardants (IFR) while simultaneously further enhancing flame retardant efficiency. In addressing this challenge, novel in-situ cemented MVC-IFR microparticles characterized by a microparticle-aggregation effect and hydrophobic structure were successfully synthesized. The micro-aggregated MVC-IFR particles not only bolstered the hydrophobicity and charring flame retardancy of PP composites compared to conventional IFR but also exhibited superior resistance to water erosion. The water contact angle (WCA) of 3MVC-22IFR reached an impressive 159°, whereas the WCA of IFR stood at 0°. Moreover, when MVC-IFR and IFR were incorporated into PP, 3MVC-22IFR/PP displayed a WCA of 108° which was a hydrophobic composite, while 25IFR/PP exhibited a WCA of 81° which was a hydrophilic composite. Notably, the hydrophobic MVC-IFR showcased greater resistance to water exposure than hydrophilic IFR, thereby maintaining its flame retardant efficacy in practical applications. Furthermore, MVC-IFR microparticles with aggregation of acid, carbon, and gas sources, facilitated the charring reactions of different components, thereby enhancing its charring flame retardant effect in PP. Remarkably, 1MVC-24/PP not only attained a UL 94V-0 rating but also achieved a glow wire flammability index (GWFI) of >960 °C, a glow wire ignition temperature (GWIT) of 850 °C, and an LOI value of 28.7 %. In contrast, 25IFR/PP failed to secure a UL 94 rating and exhibited lower GWIT and LOI values. Crucially, the peak heat release rate and total smoke release of 1MVC-24IFR/PP were markedly reduced by 76 % and 41 %, respectively, compared with those of neat PP. In summary, this study presented a novel design concept and rules for flame retardant morphology, to find a way for the development of polyolefin materials boasting both high hydrophobicity and superior flame retardancy.

A-164 Establishment and Verification of Reference Intervals for Red Blood Cell Series and Total Leukocytes in Whole Blood Counts of Chilean Adults Using refineR and Multi Criteria Expectation Maximization Methods

Abstract Background This study aimed to define RIs for red blood cell series and total leukocytes in the complete blood count, in adult patients. Methods We used a sample of 822 patients aged 18 to 60 years, both female and male. The study focused on the red blood cell series (RBC Count, hemoglobin, Hematocrit, MCV, MCH, MCHC and RDW) and total leukocytes. RIs and respective 90% confidence intervals were estimated using the refineR method and a multi-criteria method combining the Expectation Maximization algorithm, mode, antimode analysis, an adapted Horn algorithm (5 cycles of Tukey's test with intermediate trimming and 2 cycles of Tukey's test with Box-Cox transformed data if applicable after analyzing Lambda, kurtosis, and skewness coefficients) and distribution truncation based on clusters and antimode. The RIs estimates using refineR and multi-criteria methods were compared to the manufacturer's specifications (Mindray). Flagging Rates were used to validate the method that estimates the most representative RI for the population served by the laboratory. Equivalence Interval and Bias Ratio were utilized to assess the practical relevance of sex-based partitioning. Results The method based on the multicriteria approach demonstrated the best performance, with flagging rates showing results lower than 4.7% and higher than 0.9% after the truncation of the results distribution. In general, the refineR method generated very narrow RIs, while the manufacturer's specifications resulted in very wide or shifted RIs, which do not adequately represent the data distribution profile. It was identified the need to partition by sex for the parameters Red Blood Cell Count, Hemoglobin, and Hematocrit, which is in agreement with the manufacturer's specifications. Conclusions The estimated RIs better represent the laboratory-served population, highlighting the importance of adhering to ISO 15189 normative requirements. This involves verifying and/or determining RIs to provide representative information of the served population, thereby aiding in medical decision-making.

A-271 Expansion of sample viability for self-collected urine specimens containing CT/NG &amp; TV/MG utilizing the Roche cobas® 6800 System

Abstract Background The CDC estimates that 1 in 5 Americans have an STI. Home collection for STIs could help mitigate the stigma, cost, and accessibility, which contribute to low diagnosis rates and disparities in diagnosis and treatment. Home self-collected specimens occasionally arrive in the lab with volumes higher or lower than what is required by the assay manufacturer’s specifications for self-collection. This study demonstrates that sample stability is retained after temperature fluctuation via shipping - even when the correct ratio of buffer to sample has been disturbed, a precise and accurate measurement persists. Our goal is to improve accessibility to discreet, patient collected STI tests. Methods Positive samples were prepared by spiking negative urine with organisms near the manufacturer’s limit of detection (LoD). Properly collected samples were aliquoted into tubes with 5mL volumes as per manufacturer specifications. Improperly collected samples were either overfilled (9mL for CT/NG, 7mL for TV/MG) or underfilled (1mL for CT/NG, 2mL for TV/MG). Samples underwent temperature cycling to mimic summer or winter shipping conditions. Ambient temperature studies were conducted on over/underfilled specimens. All samples were baseline tested and compared qualitatively to the manufacturer's claimed LoD using the Roche c6800 and the IVD assays for CT/NG &amp; TV/MG. Results Improperly filled samples were stable at ambient temperature for 63 days for CT/NG, and 59 days for TV/MG. See chart for temperature cycling results. All samples (n=164) showed 100% qualitative agreement with their baseline result after summer and winter shipping challenges. Conclusions Urine samples that fail to satisfy the manufacturer’s self-collection specifications or have endured temperature fluctuations still yield accurate CT/NG &amp; TV/MG results. These results indicate the potential to enhance sample viability and patient accessibility utilizing validated IVD assays.

Efficient property-oriented design of composite layups via controllable latent features using generative VAE

Fiber-reinforced composites provide substantial tailoring potential, while the extensive parameters and complex coupling mechanisms pose formidable challenges to layup designs. This paper presents an efficient inverse design framework for composite layups utilizing a variational autoencoder (VAE), which is applicable to non-conventional laminates. By leveraging the VAE's exceptional feature extraction and generative capabilities, the decoder rapidly produces layups with desired properties through controllable feature vectors. Based on the stacking characteristics of layups, multi-scale one-dimensional convolutions precisely extract sequence features relevant to mechanical properties and specific manufacturing constraints. A customized loss function is formulated to constrain the latent features, while addressing the non-uniqueness problem for layups with certain mechanical properties. The developed property-oriented VAE can generate 100,000 layups in seconds, achieving an average success rate of 66.9% under comprehensive in-plane and bending stiffness design, and remains effective for 100-ply thick laminate. For comparison, the VAE model outperforms the genetic algorithm and the logic-based method in reinforced panel designs, reducing the retrieval error by 46.4% and 38.1%, respectively. The proposed approach demonstrates flexible and efficient design advantages using generative machine learning models, and is easily extendable to other inverse design scenarios.

A Co-Location Study of 87 Low-Cost Environmental Monitors: Assessing Outliers, Variability, and Uncertainty

While field research in indoor air quality (IAQ) increasingly uses large numbers of low-cost sensors, detailed validation of each sensor is becoming infeasible, ignored, or undeclared. Questions remain about whether these sensors meet manufacturer or third-party specifications and whether their utility improves with some validation, even under imperfect conditions. This study details the outcomes of a co-location experiment with 87 low-cost IAQ monitors, conducted with the objective of verifying their performance in measuring total volatile organic compounds (tVOCs), particulate matter 2.5 (PM2.5), carbon dioxide (CO2), temperature, and relative humidity. The monitors were installed next to professional-grade reference IAQ instruments in an office with controlled ventilation. A mixed validation methodology was used, involving outlier detection, uncertainty quantification, and performance metric calculations. Results showed that CO2, temperature, and humidity sensors reliably met manufacturer specifications, while tVOC sensors had significant accuracy issues, deviating by up to 79% from reference measurements—substantially more than the stated uncertainty of ±20%. PM2.5 sensors were more consistent but had an error margin of ±27%, compared to the stated ±15%. A total of 5 of the 87 sensors (5.7%) were outliers for at least one IAQ indicator. Despite the need for further long-term validation, this study highlights the importance of performing an experimental evaluation of low-cost IAQ monitors before field deployment.

Beam profile characteristics of a Varian linear accelerator across different photon energy levels

Radiotherapy employs variety of energy radiation to destroy cancer cells. A linear accelerator(also called LINAC) is the machine used to delivered external beam radiation therapy.In order to confirm the treatment planning systems that deliver the best radiation to the tumors while sparing the surrounding normal tissues, extensive measurements of dosimetric parameters are part of the commissioning procedure of a LINAC for clinical usage. This work aimed to compare and assess photon beam profiles with respect to penumbra width, symmetry, and beam flatness. Beam profile measurements were performed for this study atTMSS Cancer Center, Bogura, Bangladesh, using a linear accelerator (Varian VitalBeam SN: 5199) with 6MV,10MV and 15MV photon energies for a set of field sizes (4 × 4, 10 × 10 and 20 × 20 cm2) and various reference depths keeping the same environmental conditions. A 3D water phantom, CC13 ionization chamber (SN:18635)as a reference chamber, CC04 ionization field chamber (SN:18616) as a and IBA myQA Accept software version 1.6 were used to measure the profiles of photon energies 6 MV, 10 MV 15 MV respectively. Utilizing the Eclipse (Version: 16.1) external treatment planning system, the profile calculation was carried out. According to the manufacturer's and IEC specifications, the photon beam profile data from the current investigation are compatible, and all of the tolerances fall within the ranges of clinically acceptable tolerance.

Energy Performance of Zeolite-Based Drying Bead Desiccants Used to Dry Paddy Rice.

This study utilizes differential scanning calorimetry and thermogravimetric analysis to assess the total energy required to regenerate saturated zeolite-based drying beads (DBs) used to dry paddy rice. We quantify the required heat energy for DB regeneration by calculating the area under the curve in a heat flow rate versus time graph, with the end of the regeneration process indicated by stabilization of the DB weight. Our findings suggest that at DB regeneration temperatures ranging from 120 to 350 °C, the process varied from 813 to 22 min, demonstrating that higher temperatures lead to faster regeneration speeds. The total energy used for regeneration showed similar values at 250 and 350 °C, averaging around 2032 and 2136 kJ per kg of dried DB, respectively. Additionally, the study showed that DBs can hold water between 28.7% and 54.4% higher than the manufacturer's specifications, suggesting a reduced quantity of DBs required for effective paddy rice drying. The overall required heat energy for the regeneration process was calculated at 4.86 MJ/kg, with a carbon intensity of approximately 275.61 g of CO2-eq per kg of water removed, resulting in lower values compared to conventional drying methods. The study underscores DB's possibility of lower total energy (thermal and electrical) consumption and greenhouse gas emissions, alongside its flexibility to regenerate with intermittent energy sources.

A Perspective on Democratizing Mechanical Testing: Harnessing Artificial Intelligence to Advance Sustainable Material Adoption and Decentralized Manufacturing

Abstract Democratized mechanical testing offers a promising solution for enabling the widespread adoption of recycled and renewably sourced feedstocks. Locally sourced, sustainable materials often exhibit variable mechanical properties, which limit their large-scale use due to tight manufacturing specifications. Wider access to mechanical testing at the local level can address this challenge by collecting data on the variable properties of sustainable feedstocks, allowing for the development of appropriate, uncertainty-aware mechanics frameworks. These frameworks are essential for designing custom manufacturing approaches that accommodate variable local feedstocks, while ensuring product quality and reliability through post-manufacturing testing. However, traditional mechanical testing apparatuses are too costly and complex for widespread local use by individuals or small, community-based facilities. Despite promising efforts over the past decade to develop more affordable and versatile testing hardware, significant limitations remain in their reliability, adaptability, and ease–of-use. Recent advances in artificial intelligence (AI) present an opportunity to overcome these limitations by reducing human intervention, enhancing instrument reliability, and facilitating data interpretation. AI can thus enable the creation of low-cost, user-friendly mechanical testing infrastructure. Future efforts to democratize mechanical testing are expected to be closely linked with advancements in manufacturing and materials mechanics. This perspective paper highlights the need to embrace AI advancements to facilitate local production from sustainable feedstocks and enhance the development of decentralized, low-/zero-waste supply chains.

“Under Pressure!”

The use of digital technologies or applications can have positive and negative effects on workers: Digital technologies might support workers' decision-making by providing necessary information, but digital technologies might also lead to time pressure and mental strain. In this paper, the authors specifically analyze the characteristics of digital work and the link to mental strain to estimate the effects on work performance in industry. They report survey data from four German companies in the manufacturing, service, and logistics sector with N=279 participants. Results indicate that technology-based organizational and personal resources mitigate, while technology-based demands enhance mental stress and strain. Time pressure is the most important individual factor increasing mental stress and strain. Mental strain, in turn, negatively influences work performance. Considering such connections is crucial for human resource management in digital work contexts and specifically workers' use of and interaction with technologies beyond the analyzed specific manufacturing, service, and logistics industries.

Variability and error in measurement of infant formula powder and water: an experimental study.

Formula feeding is the only viable nutrition alternative for infants 0-6mos who cannot breastfeed. Among the drawbacks of formula feeding, however, is potential dilution or concentration errors in the formula during preparation that may lead to infant health issues. The present study aimed to investigate the accuracy of caregiver measurements as they prepared infant formula under multiple conditions, compared with manufacturer specifications. A diverse sample of caregivers (N = 84) participated in this cross-over experimental study. Participants hand-scooped infant formula powder and poured water to prepare 4oz. and 7oz. feedings, using both a standardized set of infant formula products and participants' own products. Linear mixed effects models were used to estimate fixed effects of target amount (4oz. versus 7oz) and products (participant versus researcher) on mean absolute percent error (MAPE) of measurement. Across all conditions MAPE was significantly greater for measuring powder than for water (9.0% vs. 4.4%; p < 0.001) with a combined powder and water MAPE at 13.0%. Greater measurement error was associated with the odd-sized 7oz. preparation and participants' own products. We observed considerable variability and substantial error during infant formula preparation, particularly for hand-scooping of powder, which tended toward higher values than the theoretical gold standard.

Multi-dimensional error figuring model for ion beams in X-ray mirrors

X-ray mirrors are core optical elements in synchrotron light sources, which are typically figured by ion beams. However, traditional ion beam figuring (IBF) methods cannot effectively correct both the height and 2D slope errors. Thus, what we believe to be a novel multi-dimensional error figuring model (MEFM) is proposed to integrate the height and 2D slope errors into a linear system of equations for simultaneous multi-dimensional error convergence. The weight values are determined based on specific manufacturing errors. The simulation results show that MEFM can achieve lower 2D slope and height errors than a single height or 2D slope errors in the figuring method. The power spectral density (PSD) curves before and after simulated figuring demonstrate that the low- and mid-frequency errors are corrected simultaneously. Figuring experiments on a 270 mm × 15 mm X-ray reflector showed that the height and 2D slope errors effectively converged. The results of the PSD curves indicate that MEFM is more effective than the traditional height figuring model in correcting mid-frequency errors, which further proves the validity of the solution model. This study provides an algorithmic reference for the IBF of ultra-high precision X-ray reflectors, thereby promoting the development of physics, medicine, materials, and other fields.

Analytical and clinical performance evaluation of a new NT-proBNP assay

BackgroundThe study evaluated the performance of the Mindray N-terminal pro-B-type natriuretic peptide (NT-proBNP) in a healthy population in China, focusing on creating a reference range for future clinical applications adjusted according to different demographics.MethodsThe study measured NT-proBNP in 2277 healthy individuals. We analyzed age and sex-stratified data, performed precision, accuracy, linearitcvy, and detection limit studies, and evaluated method comparison and consistency between Roche and Mindray assays on 724 serum samples. We used Excel 2010, Medcalc, and GraphPad Prism 9.ResultsIn males, the 97.5th centile NT-proBNP concentration at age < 45, 45 to 54, 55 to 64, 65 to 74 and ≧ 75 were 89.4 ng/L, 126 ng/L, 206 ng/L, 386 ng/L and 522 ng/L, respectively. In females, the concentration of NT-proBNP at the same age was 132 ng/L, 229 ng/L, 262 ng/L, 297 ng/L and 807 ng/L, respectively. The repeatability precision coefficient of variation (CV%) for NT-proBNP was between 0.86 and 1.65 in analytical performance. In contrast, the reproducibility precision (CV%) for NT-proBNP was between 1.52 and 3.22, respectively. The study found a bias of accuracy of 3.73% in low-value samples (concentration: 148.69) and 7.31% in high-value samples (concentration: 1939.08). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 125 ng/L were 96.6%, 92.3%, 84.2%, and 98.5%, respectively. In contrast, those of 300 ng/L were 94.0%, 98.2%, 95.7% and 97.5%, respectively.ConclusionsThe Mindray NT-proBNP assay showed increased levels in both males and females with age, with higher levels in women. It performs well and aligns with manufacturer specifications. We recommend adjusting cutoff values based on demographic factors.

Simulation and experimental benchmarking of a proton pencil beam scanning nozzle model for development of MR-integrated proton therapy.

MR-integrated proton therapy is under development. It consists of the unique challenge of integrating a proton pencil beam scanning (PBS) beam line nozzle with an magnetic resonance imaging (MRI) scanner. The magnetic interaction between these two components is deemed high risk as the MR images can be degraded if there is cross-talk during beam delivery and imageacquisition. To create and benchmark a self-consistent proton PBS nozzle model for empowering the next stages of MR-integrated proton therapy development, namely exploring and de-risking complete integrated prototype system designs including magnetic shielding of the PBS nozzle. Magnetic field (COMSOL ) and radiation transport (Geant4) models of a proton PBS nozzle located at OncoRay (Dresden, Germany) were developed according to the manufacturers specifications. Geant4 simulations of the PBS process were performed by using magnetic field data generated by the COMSOL simulations. In total 315 spots were simulated which consisted of a scan pattern with 5cm spot spacings and for proton energies of 70, 100, 150, 200, and 220MeV. Analysis of the simulated deflection at the beam isocenter plane was performed to determine the self-consistency of the model. The magnetic fringe field from a sub selection of 24 of the 315 spot simulations were directly compared with high precision magnetometer measurements. These focused on the maximum scanning setting of 20cm beam deflection as generated from the second scanning magnet in the PBS for a proton beam energy of 220MeV. Locations along the beam line central axis (CAX) were measured at beam isocenter and downstream of 22, 47, 72, 97, and 122cm. Horizontal off-axis positions were measured at 22cm downstream of isocenter ( 50, 100, and 150cm from CAX). The proton PBS simulations had good spatial agreement to the theoretical values in all 315 spots examined at the beam line isocenter plane (0-2.9mm differences or within 1.5% of the local spot deflection amount). Careful analysis of the experimental measurements were able to isolate the changes in magnetic fields due solely to the scanning magnet contribution, and showed 1.9 1.2 -9.4 1.2 changes over the range of measurement locations. Direct comparison with the equivalent simulations matched within the measurement apparatus and setup uncertainty in all but one measurementpoint. For the first time a robust, accurate and self-consistent model of a proton PBS nozzle assembly has been created and successfully benchmarked for the purposes of advancing MR-integrated proton therapy research. The model will enable confidence in further simulation based work on fully integrated designs including MRI scanners and PBS nozzle magnetic shielding in order to de-risk and realize the full potential of MR-integrated proton therapy.