Reproducibility Of Measurements Research Articles

Calibration correction to improve registration during cone-beam CT guided histotripsy.

Histotripsy is a non-invasive, non-ionizing, non-thermal focused ultrasound technique. High amplitude short acoustic pulses converge to create high negative pressures that cavitate endogenous gas into a bubble cloud leading to mechanical tissue destruction. In the United States, histotripsy is approved to treat liver tumors under diagnostic ultrasound guidance but in initial clinical cases, some areas of the liver have not been treated due to bone or gas obstructing the acoustic window for targeting. To address this limitation in visualization, cone-beam computed tomography (CBCT) guided histotripsy was developed to expand the number of tumors and patients that can be treated with histotripsy. The purpose of this work is to improve the accuracy of CBCT guided histotripsy by calibrating the therapeutic bubble cloud location relative to the histotripsy robot arm. The calibration correction involves creating a bubble cloud sized treatment (a few mm) in an agar-based phantom consisting of 11 layers with alternating high and low x-ray attenuation. The layers were spaced ∼3mm apart to allow visualization of mixing after mechanical disintegration from the histotripsy treatment. Bubble cloud treatments were localized using an automated algorithm that minimized a cost function based on the intensity difference within the treatment region on the pre- and post-treatment CBCT. The actual treatment location can be compared to the theoretical bubble cloud location (focal point based on the CAD model of the transducer assembly) to calculate a 3D offset (X, Y, Z), which is used as the calibration correction between the therapeutic bubble cloud location and the histotripsy robot arm. The phantom and algorithm were analyzed to determine parameters that maximized bubble cloud treatment detection (treatment duration, localization accuracy of the phantom, number of bubble clouds) and were tested on four different histotripsy transducers. Bubble cloud locations were accurately identified with the automated algorithm from post-treatment CBCT images of the multilayer agar phantom. Treating the phantom for 20seconds was associated with the greatest change in CBCT intensity. The phantom and algorithm were able to localize changes in bubble cloud location with mean residual errors (MRE) between the measured and planned translations of 0.3±0.3mm in X, -0.2±0.6mm in Y, and 0.1±1.0mm in Z. A multi-bubble cloud calibration approach with four adjacent bubble clouds provided a statistically significant lower mean absolute deviation (MAD) in measured 3D offset (0.1, 0.0 and 0.2mm in X, Y, and Z, respectively) compared to using a single bubble cloud (MAD of 0.2, 1.1 and 1.2mm in X, Y, and Z, respectively). The calibration correction method measured statistically significantly different 3D transducer offsets between the four histotripsy transducers. Creating and analyzing four adjacent bubble clouds together produced more accurate and reproducible 3D offset measurements than analyzing individual bubble clouds. The presented histotripsy bubble cloud calibration correction method is automated, accurate, and can be easily integrated in the current histotripsy workflow to improve accuracy of CBCT guided histotripsy.

EFEITO AGUDO DE PAUSAS ATIVAS SOBRE A FUNÇÃO EXECUTIVA EM CRIANÇAS: UMA REVISÃO NARRATIVA

Active breaks can contribute to better cognitive processing? The answer to this question is relevant and was addressed in this narrative review. The aim was to examine whether there is an effect of active breaks during a single session in the school environment on executive functions in children aged 3 to 12 years. A search was conducted across several databases available in the literature. The results indicated 8 studies were analyzed, with 5 reporting positive effects on executive functions, while the other 3 studies found no differences. From this, we can conclude that incorporating movement breaks into the school routine is not detrimental to executive functions. However, further studies should be conducted in this area, considering different age groups, intensity of motor activities, and the reproducibility of measures in executive function tests.

Stretching the Limits of Refractometric Sensing in Water Using Whispering-Gallery-Mode Resonators

A novel application of microresonators for refractometric sensing in aqueous media is presented. To carry out this approach, microspheres of different materials and sizes were fabricated and doped with Nd3+ ions. Under 532 nm excitation, the microspheres presented typical NIR Nd3+ emission bands with superimposed sharp peaks, related to the Whispering Gallery Modes (WGMs), due to the geometry of the microspheres. When the microspheres were submerged in water with increasing concentrations of glycerol, spectral shifts for the WGMs were observed as a function of the glycerol concentration. These spectral shifts were studied and calibrated for three different microspheres and validated with the theoretical shifts, obtained by solving the Helmholtz equations for the electromagnetic field, considering the geometry of the system, and also by calculating the extinction cross-section. WGM shifts strongly depend on the diameter of the microspheres and their refractive index (RI) difference compared with the external medium, and are greater for decreasing values of the diameter and lower values of RI difference. Experimental sensitivities ranging from 2.18 to 113.36 nm/RIU (refractive index unit) were obtained for different microspheres. Furthermore, reproducibility measurements were carried out, leading to a repeatability of 2.3 pm and a limit of detection of 5 × 10−4 RIU. The proposed sensors, taking advantage of confocal microscopy for excitation and detection, offer a robust, reliable, and contactless alternative for environmental water analysis.

Gated myocardial perfusion SPECT for evaluating left ventricular dyssynchrony in cardiac resynchronization therapy candidates: a systematic review.

Cardiac resynchronization therapy (CRT) is an intervention for heart failure patients with reduced ejection fraction who exhibit specific electrocardiographic indicators of electrical dyssynchrony. However, electrical dyssynchrony does not universally correspond to left ventricular mechanical dyssynchrony (LVMD). Gated single-photon emission computed tomography (SPECT) myocardial perfusion allows for the assessment of LVMD, yet its role in the CRT selection process remains debated. We conducted a systematic literature review to critically evaluate the evidence for the prediction and prognostic utility of SPECT for LVMD in assessing LVMD among CRT candidates. The review adhered to PRISMA 2020 Statement criteria and included articles from PubMed, Embase, and Cochrane databases. The quality of evidence was appraised using the Grading of Recommendations, Assessment, Development, and Evaluation framework. From an initial pool of 1055 records, 33 met the inclusion criteria and provided original data on the predictive value of myocardial perfusion SPECT for LVMD. Most of them measured LVMD according to established recommendations, focusing on phase histogram bandwidth (HBW) and phase histogram standard deviation (PSD). Out of 2066 patients from 27 studies, 62% (n = 1214) were qualified as CRT responders. Five studies reported SPECT-based cutoffs for predicting CRT response (HBW ranging 55°-152° and for PSD 20°-54°). Only five studies assessed the prognostic implications of baseline SPECT-measured LVMD, indicating that elevated baseline HBW and PSD values are associated with poorer outcomes. The objective and reproducible measurement of LVMD provided by SPECT underscores its potential as a valuable tool. Such assessment seems to be emerging as a promising adjunctive technique with potential to enhance CRT outcomes.

A handheld milk conductivity sensing device (Mylee) for measuring secretory activation progress in lactating women: a device validation study

BackgroundHuman milk electrolytes are known biomarkers of stages of lactation in the first weeks after birth. However, methods for measuring milk electrolytes are available only in laboratory or expert settings. A small handheld milk sensing device (Mylee) capable of determining on-site individual secretory activation progress from sensing the conductivity of a tiny milk specimen was developed. Here we evaluate the validity of a novel milk-sensing device (Mylee) for measuring the progress of milk maturation and secretory activation status.MethodsRetrospective data analysis of laboratory records generated using the Mylee device. Device conductivity measurements were assessed for accuracy, reliability and stability in rigorous laboratory tests with standard materials. A set of human milk specimens (n = 167) was used to analyze the agreement between the milk maturation score and laboratory measurements of the secretory activation biomarker milk sodium [Na+].ResultsThe Mylee device was demonstrated to have excellent reproducibility (CV95%<5%) and accuracy (error < 5%) for conductivity measurements of a small specimen (350 µl), with good device stability and almost perfect inter-device unit reliability (ICC > 0.90). With regression analysis, we revealed excellent agreement between Mylee milk maturation (MM%) output or its raw conductivity signal and laboratory measurements of conductivity and sodium [Na+] in a dataset of milk specimens (n = 167; R2 > 0.9). The Mylee MM% score showed good predictive ability for secretary activation status, as determined by sodium threshold (18 mmol/L) in human milk specimens.ConclusionsIn this study, we demonstrated the reliability and validity of the Mylee device and its ability to detect on-site milk secretory activation in a manner comparable to that of electrolyte-based methods. The novel MyLee device offers the potential to generate real-time information about the lactation stage, measured by mothers at the commodity of their home.

Changes in physical impairments in femoroacetabular impingement syndrome following arthroscopic surgery: a systematic review and meta-analysis

Abstract Femoroacetabular impingement syndrome (FAIS) is a motion-related condition causing hip pain in young active adults. Physical impairment measures of body function include objective and reproducible measures of hip mobility, muscle power, and movement coordination. Limited data on physical impairments and the effects of arthroscopic surgery exist. The aim of this systematic review was to investigate changes in physical impairments in those with FAIS, pre- and post-arthroscopic surgery. Six databases were searched for English-language studies reporting on pre- and postoperative physical impairments using physical outcome measures. Reporting quality was assessed using the Grading of Recommendations Assessment, Development and Evaluations (GRADE) framework, the Cochrane Risk of Bias tools and Methodological Index for Non-Randomized Studies (MINORS); for pooled data [standardized mean difference (SMD), and 95% confidence intervals (CI)]. Seventeen studies were included (two randomized controlled trials; fifteen pre/postintervention studies), varying from low-critical risk of bias, low-moderate on the MINORS, and very low reporting quality using the GRADE tool. Postoperatively, participants with FAIS walked with a higher peak hip flexion moment [SMD 0.5, 95% CI (0.12–0.88); heterogeneity I2 = 0%, P = .82] and reduced external rotation range [SMD −0.68, 95% CI (−1.34 to −0.01); heterogeneity I2 = 61%, P = .05]. Surgery increased participant hip flexion moment and impulse, hip strength and faster gluteus maximus contraction time. Patients demonstrated reduced hip extension, abduction and adduction angles during walking gait, and peak hip extension moments during gait and squatting. While this review found some physical impairments changed postoperatively, further research into specific subgroups of FAIS would enhance understanding and inform rehabilitation programs and optimize patient outcomes. Level of Evidence: IV (systematic review of III and IV evidence).

Reproducibility of fetal ultrasound doppler parameters used for growth assessment.

To produce standards of references for quality control and assess the reproducibility of fetal ultrasound Doppler measurements commonly used for blood flow assessment in fetal growth. Women with singleton normal pregnancies were prospectively recruited at University College London Hospital, UK, between 24 and 41weeks. Umbilical artery (UA), middle cerebral artery (MCA), and their pulsatility indices (PI), resistance indices (RI) and ratios such as cerebro-placental (CPR) and umbilical cerebral ratio (UCR) were obtained twice by two sonographers in training or after completion of training, blind to each other's measurements. Bland-Altman plots were generated, the mean differences and 95% limits of agreement (LOA) were calculated to assess intra- and interobserver reproducibility. Values were expressed as absolute values or as z-score. One hundred ten women were recruited. Overall reproducibility was variable for absolute values and highly variable for z-scores, independently from vessel sampled, index or ratio used, intra- or interobserver reproducibility. The widest absolute values of 95% LOA were 0.3 for UA PI, 0.7 for MCA PI, 0.9 for CPR and 0.3 for UCR, respectively. Regarding z-score, the widest 95% LOA were 1.9 for UA PI, 2.1 for CPR and 1 for UCR. Reproducibility was slightly better for intra- compared with interobserver variability. There was significant difference in z-score reproducibility between MCA peak systolic velocity and CPR vs UCR. Reference standards of reproducibility of fetal Doppler parameters are produced for standardization and quality-control purposes. Overall, the reproducibility for fetal Doppler parameters was variable independently from vessel sampled, Doppler index (PI or RI) or ratio used, intra- and interobserver comparison. UCR was the most reproducible parameter which should be recommended, together with UA PI, for clinical use and in research studies on fetal growth.

Electrochemical Impedance based Characterization of Membrane Separators

Abstract Separators used in classical alkaline electrolyzers have to prevent gas crossover while keeping the potential drop due to the separator to a minimum. Impedance measurements are an important way of characterizing resistivity of membrane separators. A variety of hardware has been used in the literature for such characterization. The objective of this study is to compare the relative merits and demerits of different kinds of cell hardware for such measurements. We propose the use of coin cells in membrane characterization. Here, we have compared a conventional conductivity cell with a coin cell and a T-cell, by electrochemical impedance spectroscopy studies on commercial Zirfon® membranes in 0.1M NaOH electrolyte. In the latter two cases, several configurations of membrane-electrode assembly have been studied in order to establish the reproducibility and reliability of measurements. The coin cell and T–cell hardware are seen to improve the reproducibility and reliability significantly over the conductivity cell for electrochemical characterization of membranes. Pros and cons along with possible sources of error in measurement have been analyzed in each case. The impedance data for Zirfon® in both coin and T-cell setup was observed to be reproducible and internally consistent.

Home Health Care Research for Children With Disability and Medical Complexity.

Pediatric home health care represents a vital system of care for children with disability and medical complexity, encompassing services provided by family caregivers and nonfamily home health care providers and the use of durable medical equipment and supplies. Home health care is medically necessary for the physiologic health of children with disability and medical complexity and for their participation and function within home, school, and community settings. While the study of pediatric home health care in the United States has increased in the last decade, its research remains primarily methodologically limited to observational studies. Dedicated funding and research efforts are needed to transform American home health care research to address multifaceted outcomes valued by families and providers as well as payers and government programs. In this paper, we review the recent literature in pediatric home health care and then propose an actional agenda that could address its missing evidence base. We posit that pediatricians should partner with family caregiving experts and patients to advance knowledge about child and family health outcomes, home health care use, new models of care, and optimal approaches to education and training while also considering meaningful approaches to address disparities. The creation of an American pediatric home health care data-sharing consortium, patient registry, and reproducible access and quality measures is also needed. Most importantly, efforts should center on patient- and family-centered health priorities, with the goal of ensuring equitable outcomes for every child and family.

Use of assistive technology to assess distal motor function in subjects with neuromuscular disease.

Prospective, multicentre, non-interventional study. Ninety-eight subjects aged 5 to 60 years with a confirmed NMD completed MFM items 18, 19, and 22 both on a paper support and a digital tablet. The median age of included subjects was 16.2 years. Agreement between scores as assessed using the weighted Kappa coefficient was almost perfect for the scores of items 18 and 22 (K = 0.93, and 0.95, respectively) and substantial for item 19 (K = 0.70). In all cases of disagreement, the difference was of 1 point. The most frequent disagreement concerned item 19; mainly in the direction of a scoring of 1 point less on the tablet. An automatic analysis algorithm was tested on 82 recordings to suggest improvements. The switch from original paper-based support to the tablet results in minimal and acceptable differences, and maintains a valid and reproducible measure of the 3 items. The developed algorithm for automatic scoring appears feasible with the perspective to include them in a digital application that will make it easier to monitor patients.

Model-Assisted Spleen Contouring for Assessing Splenomegaly in Myelofibrosis: A Fast and Reproducible Approach to Evaluate Progression and Treatment Response.

Background/Objectives: Accurate and reproducible spleen volume measurements are essential for assessing treatment response and disease progression in myelofibrosis. This study evaluates techniques for measuring spleen volume on abdominal MRI. Methods: In 20 patients with bone marrow biopsy-proven myelofibrosis, 5 observers independently measured spleen volume on 3 abdominal MRI pulse sequences, 3D-spoiled gradient echo T1, axial single-shot fast spin echo (SSFSE) T2, and coronal SSFSE T2, using ellipsoidal approximation, manual contouring, and 3D nnU-Net model-assisted contouring comparing coefficients of variation. Changes in spleen volume were compared to all information to assess which measurement technique tracked disease progression with the greatest accuracy. Results: The coefficient of variation in spleen volume measurements averaging over 3 sequences was significantly lower for model-assisted contouring, 1.6% and manual contouring, 3.5%, compared to ellipsoidal estimation from 3 dimensions measured on axial and coronal T2 images, 15, p < 0.001. In 4 subjects with divergent treatment response predictions, model-assisted contouring was consistent with all information while ellipsoidal estimation was not. Manual contouring tracked similarly to model-assisted contouring but required more operator time. Conclusions: Model-assisted segmentations provide efficient and more reproducible spleen volume measurements compared to estimates of spleen volume from ellipsoidal approximations and improve objective determinations of clinical trial enrollment eligibility based upon spleen volume as well as assessments of treatment response.

Reproducibility and repeatability of 18F-(2S, 4R)-4-fluoroglutamine PET imaging in preclinical oncology models.

Measurement of repeatability and reproducibility (R&R) is necessary to realize the full potential of positron emission tomography (PET). Several studies have evaluated the reproducibility of PET using 18F-FDG, the most common PET tracer used in oncology, but similar studies using other PET tracers are scarce. Even fewer assess agreement and R&R with statistical methods designed explicitly for the task. 18F-(2S, 4R)-4-fluoro-glutamine (18F-Gln) is a PET tracer designed for imaging glutamine uptake and metabolism. This study illustrates high reproducibility and repeatability with 18F-Gln for in vivo research. Twenty mice bearing colorectal cancer cell line xenografts were injected with ~9 MBq of 18F-Gln and imaged in an Inveon microPET. Three individuals analyzed the tumor uptake of 18F-Gln using the same set of images, the same image analysis software, and the same analysis method. Scans were randomly re-ordered for a second repeatability measurement 6 months later. Statistical analyses were performed using the methods of Bland and Altman (B&A), Gauge Reproducibility and Repeatability (Gauge R&R), and Lin's Concordance Correlation Coefficient. A comprehensive equivalency test, designed to reject a null hypothesis of non-equivalence, was also conducted. In a two-way random effects Gauge R&R model, variance among mice and their measurement variance were 0.5717 and 0.024. Reproducibility and repeatability accounted for 31% and 69% of the total measurement error, respectively. B&A repeatability coefficients for analysts 1, 2, and 3 were 0.16, 0.35, and 0.49. One-half B&A agreement limits between analysts 1 and 2, 1 and 3, and 2 and 3 were 0.27, 0.47, and 0.47, respectively. The mean square deviation and total deviation index were lowest for analysts 1 and 2, while coverage probabilities and coefficients of the individual agreement were highest. Finally, the definitive agreement inference hypothesis test for equivalency demonstrated that all three confidence intervals for the average difference of means from repeated measures lie within our a priori limits of equivalence (i.e. ± 0.5%ID/g). Our data indicate high individual analyst and laboratory-level reproducibility and repeatability. The assessment of R&R using the appropriate methods is critical and should be adopted by the broader imaging community.

Navigated instrumentation and ligament tensioning device enhances initial gap acquisition during total knee arthroplasty procedure: A cadaveric study.

Gap-balanced total knee arthroplasty (TKA) technique relies on initial ligament evaluation, particularly in patient-specific implantation using computer-assisted technologies. This cadaveric study aimed to compare the reproducibility and reliability of medial and lateral gap measurements between manual stress testing and dynamic ligament balancer. Initial gap acquisitions were assessed from eight cadaveric knees (four specimens) during the same navigated TKA procedure by five differently skilled surgeons (three seniors and two juniors). Medial and lateral gaps were sequentially acquired from extension to maximum knee flexion, applying manual stress prior to any bone cuts (conventional technique), and using intra-articular tensioning device placed between the tibial cut and the native femur (instrumented technique). Reproducibility was assessed using intraclass correlation coefficient (ICC), stratified by the measurement technique, the type of gaps and the operator experience. Differences in gaps (mm) between techniques were assessed using the Bland and Altmann method. The instrumented technique showed higher ICCs than the conventional technique for medial and lateral gaps (0.87 vs. 0.60, P = 0.002, and 0.92 vs. 0.25, p < 0.0001, respectively), and showed no difference in ICCs between medial and lateral gap acquisitions (0.87 vs. 0.92, p = 0.8). Senior surgeons achieved higher ICCs than juniors, while non-significant with both techniques. Differences in gaps between techniques increased with knee flexion angle (0.8, 2.8 and 3.5 mm at 10°, 45° and 90° of flexion angle, respectively) and decreased with the operator experience (p = 0.003). The instrumented balancing technique offered better reproducibility than using manual valgus and varus stress, when measuring medial and lateral gaps. Tensioning devices may play a significant role in enhancing initial gap acquisition, disregarding the flexion angle and the operator experience. Level IV (observational study involving cadaveric specimens).

A Reproducible Method for Donor Site Computed Tomography Measurements in Abdominally Based Autologous Breast Reconstruction.

We present an approach for evaluating abdominal computed tomography (CT) scans that generates reproducible measures relevant to donor site morbidity after abdominally based breast reconstruction. Seventeen preoperative CT metrics were measured in 20 patients with software: interanterior superior iliac spine distance; abdominal wall protrusion; interrectus distance; rectus abdominis width, thickness, and width-to-thickness ratio; abdominal wall thickness; subcutaneous fat volume; visceral fat volume; right/left psoas volumes and densities; and right/left rectus abdominis volumes and densities. Two operators performed measures to determine interrater reliability (n = 10). Interclass coefficients (ICCs) were calculated, and Bland-Altman plots were fashioned. Intrarater reliability was excellent (ICC > 0.9, 0.958-1) for 15 measures, and good (0.75 < ICC < 0.9, 0.815-0.853) for 2 measures. Interrater reliability was excellent (ICC > 0.9, 0.912-0.995) for 12 measures and good (0.75 < ICC < 0.9, 0.78-0.896) for 5 measures. Bland-Altman plots confirmed intra/interrater agreement. Our study meets its objective of establishing a protocol for obtaining abdominal CT measurements with high reproducibility and intrarater and interrater reliability. Although this study is not meant to weigh the particular influences of various CT measurements on clinical outcomes, we are now actively studying this with the intention of reporting our findings in the near future. Larger patient cohorts must be leveraged to determine correlations between abdominal CT scan findings and donor site outcomes using machine learning algorithms that generate models for predicting abdominal donor site complications.

Reproducibility and reliability of dental arch measurements: comparing of manual, digital, and app-based methods

BackgroundKnowing the available dental space in a patient is crucial for orthodontists to develop a good treatment plan.ObjectivesTo compare and evaluate the reliability, reproducibility, and accuracy of three measurement methods on models: conventional, mobile app, and digital software. Materials and methods: Maxillary and mandibular dental plaster models of 20 subjects with permanent dentition were analyzed. Three measurements were taken: manually using a digital caliper, using Nemocast 3D® software, and using the mobile app “Ruler.” These were performed by the same observer at the same initial time (T1) and repeated after 15 days (T2).ResultsThe three methods measured each of the quadrants and each of the dental pieces similarly, with no significant differences found. Significant differences were found between the different measurement times in the manual and app ruler measurement groups. Intra-observer consistency was also observed through Pearson correlations. The measurement from the mobile app “Ruler” presented lower values compared to the other two models, especially with the measurements taken for each quadrant.ConclusionThe three methods used for measuring dentoskeletal discrepancy are similar in terms of results. However, Nemocast 3D software showed greater reproducibility and reliability compared to the other two methods presenting consistency in the results measured at both time points, which may be useful for our diagnoses.Trial registrationThe study was conducted according to the ethical standards set by the Declaration of Helsinki for Biomedical Research and the protocol was approved by the Bioethics Committee of the University of Salamanca with number 23/1074.

Impulse oscillometry parameters and diffusing capacity of the lung in patients with pulmonary tuberculosis: is there an inter-relationship?

Assessment of pulmonary gas exchange is essential in patients with respiratory diseases. However, the diffusing capacity of the lung cannot be assessed in some patients due to their physical condition or cognitive limitations. Impulse oscillometry requires minimum patient cooperation, is easy for patients, and allows for quick, reproducible measurements. The aim of the study was to determine the relationship between impulse oscillometry parameters and diffusing capacity of the lung in patients with pulmonary tuberculosis. Methods. This was a retrospective observational study in adult patients with a confirmed diagnosis of pulmonary tuberculosis. We evaluated their spirometry, body plethysmography, Carbon Monoxide Diffusing Capacity (DLCO), and impulse oscillometry measurements. The study did not include patients with smoking experience of more than 10 pack-years, nonspecific respiratory diseases, chest surgery, and extrapulmonary causes of chest mobility restriction. The Kruskal – Wallis criterion, the χ2 criterion, Spearman rank correlation, and ROC analysis were used. Results. A moderate relationship was revealed between DLCO and IOS parameters: with frequency dependence of resistance (Rrs5–20), resonant frequency (Fres), deviation of reactance at 5 Hz from the predicted value (∆Xrs5), and reactance at 5 Hz (Xrs5) (–0.32; –0.33; –0.34; 0.32, respectively, p &lt; 0.05). The reactance area (AX) showed a considerable relationship with DLCO and alveolar volume (VA) (–0.51; –0.57, respectively, p &lt; 0.05) and a moderate relationship with the poorly Poorly Communication Fraction (PCF) 0,31 (p &lt; 0,05). The ROC analysis showed that if DLCO was less than 75%, the cut-off level of AX was 0.30 kPa/l (AUC = 0,746), and if DLCO was less than 50%, the cut-off level of AX was 0.41 kPa/l (AUC = 0,840). Conclusion. The diffusing capacity of the lung in patients with pulmonary tuberculosis correlates with the changes in total respiratory resistance and its components.

Absorption photometry of patterned deposits on IMPROVE PTFE filters

ABSTRACT The IMPROVE program (Interagency Monitoring of PROtected Visual Environments) tracks long-term trends in the composition and optics of regional haze aerosols in the United States. The absorptance of red (633-nm) light is monitored by filter photometry of 24 h-integrated samples of fine particulate matter (PM 2.5). These are collected every third day at about 150 rural and often remote locations. Systematic reanalyses of archived samples have established the reproducibility of these optical absorption measurements across decades and instrument systems, with a consistent calibration that is traceable back to 2003. IMPROVE samples for nondestructive analyses by photometry, gravimetry, and X-ray fluorescence are all collected on ring-mounted membranes of expanded PTFE (polytetrafluoroethylene). Although attractively inert, low in blank mass, and optically thin, these media yield visibly nonuniform deposits that do not admit direct interpretation according to a naïve “Beer-Lambert” formulation of optical absorption. Most IMPROVE PTFE deposits exhibit a fine-scale “pixelation” shaped by the perforated screen that supports the membrane during sample collection. This paper extends the traditional Beer-Lambert interpretive model to accommodate the patterned deposits generated by IMPROVE and similarly aggressive sampling protocols on PTFE filters. The extended model is then used to assess the bias and epistemic uncertainty in the aerosol absorption coefficient that IMPROVE has historically reported. Implications Ambient fine aerosol particles are widely collected at high sample face velocities on PTFE (Teflon®) membrane filters backed by perforated support screens. The screens’ localized blockage of airflow can channel the resulting PM2.5 sample deposits into a pattern of discrete heavily loaded “pixels”, where the screen perforations allow flow through the membrane, separated by a lightly loaded background that reflects blockage by the screen. Such non-uniform deposits, collected throughout the United States on FRM filters to monitor NAAQS compliance and on IMPROVE filters to support the Regional Haze Rule, do not meet the requirements of the Beer-Lambert model for optical absorption measurements. This paper extends Beer-Lambert theory to accommodate patterned deposits, and assesses the bias and epistemic uncertainties introduced by historical (mis)reporting based on “Beer’s Law”. For samples of moderate (and lesser) absorptance, including the bulk of those collected at rural IMPROVE sites to track regional haze, usefully tight bounds are developed for this pixelation bias.

Nickelocene SPM tip as a molecular spin sensor

Functionalization of a scanning microscopy probe with a single nickelocene allows reproducible spin-sensitive measurements of magnetic systems on surfaces. The triplet ground state of the nickelocene tip gives rise to a characteristic inelastic electron spin-flip excitation, which can change upon interaction with spin systems on the surface. These changes, together with theoretical simulations, enable us to determine the local spin moment on the surface. In this paper, we discuss the experimental and theoretical aspects of nickelocene-tip measurements. We rationalize the interactions between the nickelocene spin and the magnetic centers using a spin Heisenberg and dipole model, complemented by cotunneling theory, and compare the simulated dI/dV with selected experimental results. We developed a Python script to simulate this magnetic interaction, which is available on GitHub.

Evaluation of Reproducibility of Measurements of Peripapillary Blood Flow with Laser Speckle Flowgraphy in Healthy and POAG Subjects.

Peripapillary blood flow is of diagnostic value in glaucoma. We investigated the reproducibility of peripapillary blood flow measurements in healthy individuals and in open-angle glaucoma (OAG) patients with the Nidek laser speckle flowgraphy (LSFG)-NAVI system. Blood flow was calculated as the mean of vascular area (MV), mean of tissue area (MT), and mean of overall flow (MA). Intra-rater, inter-session, and inter-rater reproducibility were assessed by determining the intraclass correlation coefficient (ICC) and coefficient of variance (COV). There were 28 healthy subjects and 16 patients with OAG who participated in this prospective single-center trial. ICC and COV of intra-rater reproducibility were assessed in MV as 0.901; 6.424, MT as 0.909; 4.025, and MA as 0.965; 4.168. Inter-session reproducibility yielded ICC and COV values of MV (0.834; 9.223), MT (0.904; 6.215), MA (0.909; 7.069). Inter-rater reproducibility was computed for MV as 0.78; 9.758, MT as 0.890; 7.210, and MA as 0.888; 6.942. There was a significant difference in MA (p = 0.0184) between the healthy individuals (mean 36.299) and the OAG group (mean 24.944), which was not observed for MV (p = 0.0735) or MT (p = 0.1351). High reproducibility of measurements of peripapillary blood flow with the LSFG system was demonstrated in both groups. There is a difference in peripapillary blood flow between healthy controls and OAG patients.

Instrumental Colorimetric Evaluation of Combined Enamel and Dentin Composite Resins Compared to the Vita Classic Shade Guide

Accurate color determination in dental restorations is crucial for achieving aesthetically pleasing and functional results. Traditionally, color selection has been performed using visual methods, which are subject to observer variability and factors such as lighting and experience. However, the use of instrumental technologies like spectrophotometry has allowed for greater objectivity and reproducibility in color measurement. This study aims to evaluate the accuracy of color determination in composite resin restorations using spectrophotometry, comparing the results obtained with the Vita Classic shade guide. A total of 120 samples were prepared using 4 types of composite resins and 3 enamel/dentin combinations (A2, A3, and A3.5), with 0.7 mm thickness for enamel and 1.3 mm for dentin, achieving a final thickness of 2 mm. Color measurements were taken with a Vita™ Easyshade® spectrophotometer, and the results were expressed in terms of ΔE using the CIE Lab* formula. Normality (Shapiro-Wilk) and homoscedasticity (Levene) tests were applied, and one-way ANOVA was used to assess differences between resin brands and shades. The results showed that, although no statistically significant differences were found in the A2 and A3 shades between brands, the A3.5 shade exhibited significant variations, with Filtek Z350 XT® 3M Espe Solventum being the resin that showed color values closest to the ideal.