Variance Of Measurements Research Articles

Radiographic Indicators of Craniocervical Instability: Analyzing Variance of Normative Supine and Upright Imaging in a Healthy Population.

Single-institution retrospective review. To establish baseline ranges and variability of 7 radiographic measurements of the cervical spine in a healthy patient population as potential diagnostic tools for craniocervical instability. Craniocervical instability, common in patients with connective tissue disease such as Ehlers-Danlos Syndrome, often presents with a wide range of symptoms, including neck pain. Current diagnostic methods employ a range of clinical and radiographic features, but diagnostic challenges remain due to missed indications on static imaging and a lack of standardized measurement values and normalized variance. Seventy-two healthy patients with cervical imaging were analyzed. Surgimap software was used to annotate supine computed tomography images, flexion, extension, and neutral x-ray images for measurement. These measurements included the atlanto-dental interval, clival-axial angle, basion-dens interval, basion-axis interval, perpendicular basion to the inferior aspect of C2, also known as Grabb Oakes measurement, and the hard palate to C1 and hard palate to C2. Statistical analysis assessed differences among imaging modalities, and coefficients of variation were calculated for each measurement. Our cohort consisted of a total of 72 patients with a mean age of 64 (SD: 13.54). All measurements except for the basion-axial interval and atlanto-dental interval demonstrated a significant difference between extension and flexion x-ray measurements. clivo-axial angle, hard palate to C1, and hard palate to C2 demonstrated the lowest coefficients of variance across imaging modalities. Understanding normal variance in cervical measurements is invaluable for accurate CCI diagnosis. Using a cohort of healthy patients, this study delineates the distribution and spread of 7 cervical measurements, delineating reference values and variability in these key measurements and highlighting their potential for use as imaging markers for CCI. Level III.

A 3D fast MR elastography sequence with interleaved multislab acquisition and Hadamard encoding.

To enhance the functional capability of MRI, this study aims to develop a novel MR elastography (MRE) sequence that achieves rapid acquisition without distortion artifacts. A displacement-encoded stimulated echo (DENSE) with multiphase acquisition scheme was used to capture wave images. A center-out golden-angle stack-of-stars sampling pattern was introduced for improved SNR and data incoherence. A combination of Hadamard encoding and interleaved multislab acquisition schemes was used to increase the acquisition efficiency of MRE data with multiple directions and phase offsets. A generalized parallel-imaging and compressed-sensing method was further applied to accelerate the acquisition process. The imaging results of the proposed sequence were compared with those from six gradient echo (GRE)/EPI/DENSE-based MRE sequences via phantom and brain acquisitions. The proposed sequence achieved a 6-fold acceleration compared with GRE MRE. With the application of a conventional parallel-imaging and compressed-sensing algorithm, the scanning speed was further accelerated by 8-fold, matching the speed of EPI-based MRE. Phantom tests revealed small variances in stiffness measurements across the seven sequences (< 9.23%). The proposed sequence exhibited a higher contrast-to-noise ratio (1.38) than the two EPI-based sequences (0.61/0.76) and similar to GRE-based sequences (1.34/1.22/1.58). Brain imaging validated the effectiveness of the proposed sequence in accurate stiffness estimation and distortion artifact avoidance. A rapid DENSE-based MRE sequence with interleaved multislab acquisition and Hadamard encoding was developed at a speed matching EPI-based sequences, without compromising SNR or introducing distortion artifacts.

The psychometric properties of the Pearlin Mastery Scale in persons living with restless legs syndrome.

Restless Legs Syndrome (RLS) is a neurological disorder characterized by an urge to move arms and legs, commonly combined with distress, pain and motor restlessness. It can cause fragmented sleep, daytime symptoms, and decreased quality of life. Pharmacological treatment can suppress symptoms, but not cure. When challenged with illness, people may turn to their inner psychological resources such as self-esteem and mastery. The Pearlin Mastery scale was developed to study stress and coping, is commonly used in people with chronic illnesses, however, not yet validated in people with RLS. The aim was to test reliability and construct validity of the Pearlin Mastery Scale in persons with RLS. A cross-sectional postal survey including the Pearlin Mastery Scale, Restless Legs Syndrome-6 Scale, Pittsburgh Sleep Quality Index and Patient Health Questionnaire was sent out to members (n = 1500) of the national RLS association and 788 (52.5%) agreed to participate. Data were analyzed using classical test theory, Confirmatory factor analysis and Rasch measurement theory analysis. Hypothesis testing for construct validity was done by bivariate correlation analyses. Most respondents were women (65%), retired (71%) and had a mean-age of 70.8 years (SD 11.4). The 7-item version of the Pearlin Mastery Scale showed poor fit to the one factor model. After omitting the two positively worded items (i.e., item 4 and 6), the 5-item version was found to be unidimensional, with satisfactory internal consistency. However, all items showed considerable ceiling effects. No measurement variance was seen regarding age-groups or sex. Higher level of mastery was moderately correlated with less depressive symptoms but only weakly correlated to RLS-related sleep problems. The 5-item version of the Pearlin Mastery Scale is suggested to be used in persons with RLS due to its acceptable psychometric properties. The instrument could be applied as an outcome measure for behavioral change interventions aiming to support mastery in RLS.

The QIBA Profile for Diffusion-Weighted MRI: Apparent Diffusion Coefficient as a Quantitative Imaging Biomarker.

The apparent diffusion coefficient (ADC) provides a quantitative measure of water mobility that can be used to probe alterations in tissue microstructure due to disease or treatment. Establishment of the accepted level of variance in ADC measurements for each clinical application is critical for its successful implementation. The Diffusion-Weighted Imaging Biomarker Committee of the Quantitative Imaging Biomarkers Alliance (QIBA) has recently advanced the ADC Profile from the consensus to clinically feasible stage for the brain, liver, prostate, and breast. This profile distills multiple studies on ADC repeatability and describes detailed procedures to achieve stated performance claims on an observed ADC change within acceptable confidence limits. In addition to reviewing the current ADC Profile claims, this report has used recent literature to develop proposed updates for establishing metrology benchmarks for mean lesion ADC change that account for measurement variance. Specifically, changes in mean ADC exceeding 8% for brain lesions, 27% for liver lesions, 27% for prostate lesions, and 15% for breast lesions are claimed to represent true changes with 95% confidence. This report also discusses the development of the ADC Profile, highlighting its various stages, and describes the workflow essential to achieving a standardized implementation of advanced quantitative diffusion-weighted MRI in the clinic. The presented QIBA ADC Profile guidelines should enable successful clinical application of ADC as a quantitative imaging biomarker and ensure reproducible ADC measurements that can be used to confidently evaluate longitudinal changes and treatment response for individual patients.

Cyclohexane dehydrogenation: Critical evaluation of parameter estimation procedures for kinetic modeling

In the present paper a comparison between different parameter estimation procedures commonly used for the kinetic modeling of chemical reaction is performed, based on experimental measurements of the cyclohexane dehydrogenation to benzene. The obtained results show that, when the Arrhenius equation parameters are estimated from estimates of the rate constant taken at different temperatures, larger parameter uncertainties and correlations are obtained, particularly when the variances of the experimental measurements are not considered during the estimation process. It is also observed that an apparent kinetic compensation effect occurs when the experimental data are separated according to the inlet partial pressure and catalyst mass in the reactor, mainly due to the existing and unavoidable experimental uncertainties and parameter correlations. Additionally, it is shown that larger uncertainties and correlations are obtained when the parameter estimates are computed through the differential method, which can also lead to poorer model predictions of the experimental data. Finally, it is shown that the simultaneous one-step estimation of all model parameters through the integral method and considering the available experimental uncertainties can provide the most accurate parameter estimates, making use of mathematical expressions that describe how variances of the experimental measurements depend on the experimental conditions.

A preliminary study on the stability of bare footprint linear measurements in four motion states

In some crime scenes, there may be bare footprints. Analyzing and testing the linear measurements of bare footprints in crime scenes can play an important role in personal analysis and individual identification. However, the linear measurements of bare footprints may be influenced by different motion states, leading to changes in length and width or even significant deviations. Previous studies focused on the linear differences between static and dynamic footprints, and failed to take the speed factor into consideration. This paper studied the stability and change regularities of the linear measurements of bare footprints in four different motion states: standing, normal walking, fast walking and trotting. Dust footprints of the right feet were collected from 80 healthy young adults under these four motion states. Seven linear measurements were obtained for each footprint using the Reel method, totaling 2240 data sets. One-way repeated measures ANOVA was used to assess the measurement variations across the four states. The results showed that there were statistically significant variances in the length measurements (A1-A5) between the standing state and other motion states, whereas no statistically significant variances were observed between the three dynamic states. It was found that the mean values of the five length measurements (A1–A5) increased from static to dynamic state, and then gradually decreased slightly as the walking speed increased. Additionally, no significant differences were found in the two width measurements (MPJ Width and Calc Width) between the four motion states. As a preliminary study, this study can provide a reference for the analysis of bare footprints in different motion states extracted from crime scenes.

Reliability of Wrist Arthroscopy in the Diagnosis and Treatment of Triangular Fibrocartilage Complex Tears

Wrist arthroscopy is considered the gold standard for diagnosis of intra-articular wrist conditions including triangular fibrocartilage complex (TFCC) tears; however, the ability to reliably diagnose TFCC pathology during wrist arthroscopy is unclear. The purpose of this study was to assess the reliability of the diagnosis of TFCC tears on wrist arthroscopy videos. Five hand surgeons reviewed 43 cases on a secure web-based platform at two time points separated by 4-6 weeks. Each case included a deidentified clinical vignette and wrist radiographs with ulnar variance measurements and an arthroscopy video of ulnar wrist pathology, averaging 42 seconds. Surgeons were queried on the presence of TFCC tear and Palmer and Atzei classifications. Interobserver/intraobserver reliabilities were determined using kappa coefficients. The interobserver reliability regarding the presence/absence of TFCC tear was fair-good, with kappa coefficients of 0.596 in the first round of case review and 0.708 in the second round. The overall intraobserver reliability for the presence/absence of TFCC tear was also fair-good, with a kappa coefficient of 0.567. For cases with central TFCC tears, the interobserver reliability regarding the presence of TFCC tear was perfect, with a kappa coefficient of 1.0. When central tears were excluded, the kappa coefficients decreased to 0.322 and 0.368 in each round. The interobserver reliability for the Palmer and Atzei classifications was low, with kappa coefficients of 0.220 and 0.121 in the first round and 0.222 and 0.123 in the second round. Experienced wrist arthroscopy surgeons demonstrated fair-good interobserver reliability for the diagnosis of TFCC tear on wrist arthroscopy. However, when central TFCC tears were excluded, interobserver reliability was poor. These findings demonstrate a need for a focus on education for wrist arthroscopy anatomy. This investigation demonstrated poor agreement in surgeon identification and classification of TFCC tears, aside from central TFCC tears. The low reliability has a direct bearing on treatment considerations for TFCC tears.

A Novel Method for Measuring the Performance of Decision Alternatives in Multi-Criteria Decision Making: Proportional Superiority Approach (PSA)

In the face of increasing complexity and uncertainty, new multi-criteria decision making (MCDM) methods facilitate making informed and rational decisions by enhancing problem-solving skills. Therefore, the discovery of new MCDM methods is of great importance. In this context, this study introduces a new MCDM model (Proportional Superiority Approach-PSA) based on the fundamental logic of measuring the performance of decision alternatives, which relies on the proportional increase of decision alternatives to each other, aiming to expand the modeling logic of MCDM and enrich MCDM literature. Initially, a comparative analysis of the proposed method was conducted. According to the findings, although the relationship of PSA with other MCDM methods included in the study was high, it was found to be different from those MCDM methods. Therefore, based on the results of the comparative analysis, it was observed that the proposed method is credible and reliable. In the scope of the simulation analysis, 10 scenarios were obtained, and it was found that as the number of scenarios increased, the relationship levels of the PSA method with other methods differed and decreased. Furthermore, the PSA method was found to be capable of discriminating between the performances of decision alternatives through variance measurement. Finally, in the analysis, the level of variance of the PSA method was measured within the scenarios, and it was found that the variances of the PSA method were homogeneous within the scenarios. Therefore, according to the results of the simulation analysis, it was evaluated that the PSA method is robust and stable.

Evaluation of Normal Ranges of Wrist Radiologic Indexes in Jordanian Population.

The wrist is a complex joint that plays a role in several everyday tasks. Various radiological indices have been created to assess the alignment and structure of the wrist using standard X-ray images. Nevertheless, these indicators may differ based on variables such as age, gender, ethnicity, handedness, and wrist position. This research aimed to assess the radiological indices of the wrist in a group of healthy people from Jordan and investigate the impact of age and gender on these indices. We obtained data from a sample of 385 patients who presented at our hospital with minor non-specific wrist pain and satisfied the specified criteria for inclusion. We conducted measurements of radial inclination, radial height, volar tilt, ulnar variance, and carpal height ratio using both anteroposterior and lateral views of the wrist. We used linear regression and independent sample t-test to examine the correlation between age, gender, and radiological indicators. The reliability of the measurements was assessed using the intraclass correlation coefficient (ICC). Our study revealed a negative correlation between age and carpal height ratio (r = -0.13, p = 0.03). However, no significant gender differences were seen in any of the radiological indices (p > 0.05). Our findings indicate that ulnar variance had the greatest level of reliability across observers, with an intra-observer intraclass correlation coefficient (ICC) of 0.95 and an inter-observer ICC of 0.8. Conversely, volar tilt exhibited the lowest inter-observer reliability, with an ICC of 0.1.Our results provide a valuable point of reference for the wrist morphology and alignment in the Jordanian population. Our suggestion is that the carpal height ratio might indicate alterations in the wrist joint due to aging, whereas ulnar variation may serve as a dependable indicator of wrist alignment. We suggest doing more research to investigate the biological and anatomical factors behind these results and to compare them with other demographic groups.

Biolayer interferometry for adeno-associated virus capsid titer measurement and applications to upstream and downstream process development

Faster and more accurate analytical methods are needed to support the advancement of recombinant adeno-associated virus (rAAV) production systems. Recently, bio-layer interferometry (BLI) has been developed for high-throughput AAV capsid titer measurement by functionalization of the AAVX ligand onto biosensor probes (AAVX-BLI). In this work, an AAVX-BLI method was evaluated using Octet® AAVX biosensors across four rAAV serotypes (rAAV2, 5, 8, and 9) and applied in an upstream and downstream processing context. AAVX-BLI measured capsid titer across a wide concentration range (1×1010 – 1×1012 capsids/mL) for different rAAV serotypes and sample backgrounds with reduced measurement variance and error compared to an enzyme-linked immunosorbent assay (ELISA) method. Biosensors were regenerated for repeated use, with lysate samples showing reduced regeneration capacity compared to purified and supernatant samples. The AAVX-BLI method was applied in a transfection optimization study where direct capsid titer measurement of culture supernatants generated a representative response surface for total vector genome (VG) titer. For rAAV purification, AAVX-BLI was used to measure dynamic binding capacity with POROS™ CaptureSelect™ AAVX affinity chromatography, showing resin breakthrough dependence on operating flow rate. Measurement accuracy, serotype and sample background flexibility, and high sample throughput make AAVX-BLI an attractive alternative to other capsid titer measurement techniques.

Dynamic and Static Complementary Balance Theory-Based Functional Exercise Combined With Stepwise Rehabilitation Training Improves Postoperative Hip Function Recovery in Patients Undergoing Total Hip Replacement

To analyze the application value of dynamic and static complementary balance theory-based functional exercise combined with stepwise rehabilitation training in postoperative hip function recovery in patients undergoing total hip replacement (THR). The clinical data of 118 inpatients undergoing THR between June 2022 and June 2023 were retrospectively collected. Among the patients, 57 were given perioperative stepwise rehabilitation training (the control group), and 61 were given a combination of functional exercise based on static and dynamic complementary balance theory and stepwise rehabilitation training during the perioperative period (the combination group). The postoperative recovery status and the incidence of postoperative complications in the two groups were recorded. During postoperative recovery, the patients were assessed for pain with the visual analogue scale (VAS) and for self-efficacy with the Self-Efficacy for Rehabilitation Outcome Scale (SER). Hip function was measured and compared between the two groups at 2 weeks, 4 weeks and 8 weeks after surgery. With regard to the primary outcome indicator, the postoperative length-of-stay was (7.63±1.36) d in the combination group, which was shorter than the (8.22±1.48) d in the control group, and the difference was statistically significant (t=2.257, P=0.026). As for the secondary outcome indicators, no statistically significant difference was observed in the incidence of postoperative complications between the two groups (4.92% vs. 14.04%) (P>0.05). The perioperative VAS scores in the two groups showed an interaction effect according to the repeated measurement variance test (P<0.05). The postoperative VAS scores in both groups declined significantly compared to the preoperative scores (P<0.05), and the VAS score decreased gradually over time after surgery (P<0.05). The VAS scores in the combination group at 7 and 14 days after surgery were lower than those in the control group (P<0.05). At 14 days after surgery, the scores for the coping and the task dimensions and the total score of SER increased in both groups compared with those at 3 days after surgery (P<0.05), with the combination group showing higher scores than the control group did (P<0.05). After surgery, the scores for the dimensions of deformity, pain, function, and joint mobility and the total score of the Harris Hip Scale revealed interaction effects in the two groups according to the repeated measurement variance test (P<0.05), with these scores increasing gradually over time after surgery (P<0.05), and the scores in the combination group were higher at 4 and 8 weeks after surgery compared to those in the control group (P<0.05). The combination of functional exercise based on dynamic and static complementary balance theory and stepwise rehabilitation training shows an advantage over stepwise rehabilitation training alone in enhancing the self-efficacy of THR patients, relieving the postoperative pain, shortening the length-of-stay, and improving the hip function in patients.

The Relationship between Structure of the Wrist and Function in a Japanese and Caucasian Population.

Background: Factors such as age and joint structure affect normal wrist motion. The midcarpal joint participates in flexion/extension, radial-ulnar/deviation (RUD), and since lunate/wrist type-2 is likely more stable than a lunate/wrist type-1, we suggest that midcarpal joint structure will affect wrist motion. Our purpose was to compare wrist motion in Caucasian and Japanese populations and to associate motion with midcarpal joint morphology. We hypothesised that radiographic structure would correlate with wrist motion. Methods: A total of 164 patients with normal wrist radiographs were included. Clinical measurements included wrist extension, flexion and RUD. Radiographic measurements included the radiocarpal joint: ulnar variance, radial height, radial inclination, volar inclination and carpal joint measurements: lunate type, capitate circumference and each of its joints contact measured and calculated as a proportion of capitate circumference. Results: The groups differed in wrist motion and in multiple radiographic measurements. When the two populations were analysed together, there were no significant associations between midcarpal joint type and wrist motion. The radiocarpal joint: ulnar variance was correlated with extension and radial deviation. Radial height was directly related to flexion, and both radial height and radial inclination were directly correlated with ulnar deviation. The intracarpal measurements: The main measurement affecting motion was the contact between the capitate and the scaphoid (as a proportion of capitate circumference) with lesser correlations of the contact of the capitate with the trapezoid and hamate. The most significant measurement associated with a lunate type-2 was scaphoid contact with the capitate p = 0.01. Logistic regression demonstrated that the measurements most associated with wrist motion were scaphoid contact with the capitate/capitate circumference and hamate contact with the capitate/capitate. Conclusions: This study supports discrepancies in wrist motion amongst different racial cohorts, and a relationship between bone/joint structure in the wrist and wrist motion. This can help treat wrist pathology. Level of Evidence: Level III (Diagnostic).

High surface area inorganic minerals show promise in protecting carbon from soil organic amendments

Protecting soil organic compounds could assist with global efforts to mitigate climate change, as well as improve soil health. Recent research has indicated that high surface area inorganic minerals (HSAIMs) can protect soil organic matter (OM). We evaluated if adding HSAIMs to soils can protect carbon from common organic inputs added to fallow soils prior to planting. Four added HSAIMs were investigated – two manufactured zeolites, one natural zeolite and bentonite clay – along with a carbon-rich (peat moss) and carbon-poor (composted cow manure) OM source. The added HSAIMs and organic sources were incorporated into a microbially active (clayey Vertisol) and inactive (sandy Arenosol) soil at application rates of 20 tonnes.ha–1 for the minerals and 60 tonnes.ha–1 for the organics. The treatments were incubated for three months under laboratory conditions and were subjected to continuous wetting-drying cycles. Peat moss resulted in higher organic carbon (Corg) and OM losses than cow manure. Moreover, the addition of HSAIMs to the Peat Moss+Arenosol treatments appeared to slightly enhance these losses, albeit not significantly (p>0.05). Carbon/nitrogen (C/N) ratios revealed that the Arenosol treatments were depleting soil N to access the carbon provided by the peat moss. For all other treatment combinations, the addition of HSAIMs promoted greater retention of Corg (p<0.05 in one treatment combination) and OM (p<0.05 in four treatment combinations), relative to the controls. Modelling carbon balances using OM data was more effective than using direct Corg values, due to strong Corg measurement variance. Modelled Corg data revealed the added HSAIMs achieved up to 25 % carbon protection, with the manufactured zeolites particularly effective. The study shows promise for added HSAIMs to protect carbon released from decomposing organic amendments added to fallow soils. However, addition of these minerals to N-limited soils receiving carbon-rich amendments might accelerate carbon losses.

Intersession reliability of center of pressure measurement during bipedal standing with different count-back orders

IntroductionDual-task assessments can identify changes in postural control during balance assessments. Static standing with backward counting is frequently used to evaluate postural control while dual-tasking. The most reliable countdown method for standing postural stability has not yet been defined. Research objectiveto investigate postural stability's intra- and inter-day reliability while backward counting in different steps. MethodThirty-nine healthy adults (20 females, 26.94 ± 7.55 years) completed 70 s trials of stability tests with no dual-task, counting backward under five conditions (in ones, tows, threes, fours, and fives) while standing on a force-plate in three sessions: two sessions were on the same day, and the third session was one-week apart. The repeatability of measurements was tested using repeated-measure analysis of variance, interclass correlation, and standard error of measurements. ResultsThe interclass correlation scores ranged from 0.67 to 0.92, and the standard error of measurements ranged from 2.9% to 13.4%. No significant systematic changes (p < 0.05) occurred between the testing sessions for any backward counting. DiscussionThe backward counting showed higher reliability when performed in condition 5 (counting backward in five's). The inter-day reliability scores were greater than intera-day reliability. ConclusionsDual-tasking with most backward counting (in ones to fives) is reliable, and a quantitative assessment of the center of pressure could be used to monitor the changes in postural stability between sessions.

Investigation of variability in the matrix effect on stable isotope-labeled internal standards in liquid chromatography-tandem mass spectrometry analysis of 25 pesticides in vegetables.

The matrix effects (ME) in simultaneous analysis of pesticide residue using liquid chromatography-tandem mass spectrometry (LC-MS/MS) were evaluated by comparing the slopes of matrix-matched and reagent-only calibrations of four types of vegetable samples. Both the sampling and measurement variances of the ME were also determined using one-way analysis of variance. Substantial ion suppression (ME<-20%) was observed in komatsuna, spinach, and tomato when a modified Japanese official method was implemented. The ME magnitude varied significantly due to sample variability for some pesticides, but it varied by no more than 4% as a result of analytical procedure variance. This study also showed that the addition of stable isotope-labeled internal standards at low concentrations improved the recovery of pesticides from samples at various residue levels. The findings of this study highlight the importance and practical application of internal standards and the matrix-matched calibration method in residue analysis using LC-MS/MS.

Cooperative Localization under Ionospheric Scintillation Events

Ionospheric scintillation causes major impairments to Global Navigation Satellite System (GNSS) in low-latitude regions. In severe scenarios, this event can lead to complete loss of lock, thus making GNSS measurements unusable for navigation. In this paper, we derive a cooperative localization algorithm where a set of partially connected aircraft exchange messages with neighboring nodes on the network to improve their own position estimates. We consider the scintillation events as abrupt changes in the measurement variance, which are modeled by a discrete-valued Markov process at the nodes which have access to GNSS measurements. Simulation results show that Markovian modeling and cooperation via factor graph message passing reduce the average 3D root mean square localization error and yield an average vertical position error that meets civil aviation standards for approach and landing.

Chemical characterization of cement samples by radio-analytical methods namely external (in air) PIGE, INAA and ED-XRF for assessing their quality and method validation of radioanalytical techniques

This paper demonstrates novel application of neutron and proton based nuclear analytical techniques for the rapid evaluation of cement quality in terms of compressive strength using Ca to Si ratios. Preliminary phase characterization was performed using X-ray diffraction patterns. External PIGE method was optimized and applied for direct analysis of “as received” samples in thin mylar foils with reduced turn-around time of analysis. Moreover, Pneumatic Carrier Facility at Dhruva reactor of BARC was utilized for NAA for rapid and short irradiation of samples followed by analysis. Quality control of both NAA and PIGE methods were done using several geological Certified / Standard Reference Materials (CRMs and SRMs). EDXRF was employed as alternative analytical technique for comparative evaluation. Statistical evaluation was performed in terms of t-test and F-tests to understand the reliability of measurement and acceptable variance of the results. Eight cementitious samples were analyzed and their compressive strengths were evaluated using NAA and PIGE.

A novel method for holdup measurement of three phases by an ultrasonic device with the flexible substrate

The precise measurement of multiphase flow holds significant importance across diverse industrial contexts. However, rigid probes struggle with the variable dimensions of curved surfaces, while flexible probes are hindered by fragility, susceptibility, and challenges in large-scale production. Herein, we propose an ultrasonic device featuring a flexible substrate that seamlessly amalgamates flexibility and rigidity to enable precise measurement of three-phase flow. Through simulation, we determine the optimal ultrasonic frequency (1 MHz) and flexible substrate thickness (3 mm) for a specified probe and pipe size (20 mm). A novel concept, the specific attenuation coefficient (SAC), derived from the voltage-amplitude of transmitted and received signals and propagation distance, is introduced to differentiate between oil and water. The discrepancy between measured and actual three-phase holdups are 0.55 %, 0.36 %, and 0.59 % for water, gas and oil, respectively, with a variance of measurement results 0.027.

Decreased portal vein attenuation and liver enhancement with reduced intravenous contrast dosage during the national iodinated contrast shortage of 2022.

The worldwide shortage of intravenous (IV) Omnipaque iodinated contrast (Iohexol, GE Healthcare; Milwaukee, WI, USA) forced institutions to adopt various policies regarding contrast allocation. We sought to evaluate the impact of our hospital's response to the shortage, which was to decrease the dose of IV contrast from 100 mL to 75 mL for patients weighing between 45.4 and 136 kg (100-300 lbs) undergoing abdominal computed tomography (CT) examinations. The main objective was to assess for any differences in liver attenuation and enhancement between contrast dosages. Secondary outcomes included assessing differences in aortic and portal vein attenuation, the variance in attenuation measurements, and whether radiology reports included the correct IV contrast dose. Consecutive CT abdomen or CT abdomen and pelvis examinations without and with contrast were analyzed for the 3 months before the contrast shortage and for 3 months during the contrast shortage. Attenuation in Hounsfield units (HUs) was measured in the liver on pre-contrast and portal venous phase images. Vessel attenuation was measured in the aorta (arterial phase) and main portal vein (portal venous phase). Standard deviation of liver attenuation measurements was recorded as an indicator of signal-to-noise. Liver enhancement was calculated as the difference between liver portal venous phase attenuation and pre-contrast attenuations. Thirty-nine fixed dose (100 mL) and 36 reduced dose (75 mL) consecutive CT studies were included in the study. There were no significant differences between the two groups with respect to baseline characteristics such as age, weight, body mass index, and gender. There was no significant difference in pre-contrast liver attenuation between groups, but there was statistically significant greater liver attenuation (99.6 vs. 91.2 HU, P = 0.04) and liver enhancement (51.5 vs. 39.1 HU, P < 0.0001) during the portal venous phase for the fixed-dose group compared to the reduced dose group. There was significantly greater main portal vein opacification during the portal venous phase for the fixed dose group (146.6 vs. 122.2 HU, P < 0.0001). No significant difference was found in aortic opacification during the arterial phase (245 vs. 254 HU, P = 0.52). There was no difference in the standard deviation of liver attenuation measurements on the portal venous phase between the groups. The dose was reported correctly in all the patients receiving the fixed dose and in 92% of patients receiving the reduced dose, which was not statistically significant (P = 0.11). Reducing the IV contrast dose from 100 mL to 75 mL Omnipaque 350 in patients weighing 45.4-136 kg (100-300 lbs) undergoing an abdominal CT examination resulted in significantly decreased portal vein opacification and liver enhancement. In particular, liver enhancement and calculated iodine concentrations fell below suggested thresholds for adequate conspicuity of liver lesions. The change in contrast administration protocol also led to more errors in contrast dose reporting in the radiologist's report. These findings are broadly applicable to many practice settings and can help inform strategies in response to any potential future-iodinated contrast shortage.

Addressing Cognitive Assessment Disparities Among Hispanic Adults: Adapting the MoCA-SA for Improved Accuracy and Accessibility Among Spanish-speakers.

Hispanic adults display a higher likelihood of early-stage cognitive decline than their White counterparts yet receive fewer clinical diagnoses. This troubling trend highlights the significance of longitudinal surveys like the National Social Life, Health, and Aging Project (NSHAP) in monitoring cognitive changes in aging Hispanics. Using NSHAP's Rounds 2 and 3, we observed notable cognitive score differences between English and Spanish speakers, as assessed by the survey-adapted version of the Montreal Cognitive Assessment (MoCA-SA). Our study aims to discern if statistical adjustments can reduce measurement variance in global cognition scores between these language groups. We applied modification indexes, two-parameter item response theory models, and split-sample testing to pinpoint items that exhibit resilience to language-related bias among our Hispanic sample. From this analysis, an abbreviated version of the MoCA-SA, termed MoCA-SAA, was introduced. Subsequently, we juxtaposed the performance and predictive validity of both MoCA versions against four consequential outcomes indicative of cognitive decline. Our refined methodologies enabled the identification of consistent items across both language cohorts. The MoCA-SAA demonstrated a performance and predictive validity in line with the original MoCA-SA concerning outcomes linked to cognitive deterioration. The translated measures ensure the inclusion of Hispanic Spanish speakers in NSHAP, who might otherwise be overlooked. The statistical adjustment outlined in this study offers a means to mitigate potential measurement disparities when assessing overall cognition. Despite these advancements, we acknowledge persistent issues related to the translation of the MoCA-SA into Spanish that warrant further attention.