High Rate of Change of the Foot in Ecuadorian Children: The Need for Proper Shoe Design.

BACKGROUND: Physiological changes in the foot may be influenced by external factors such as shoe types or demographic parameters, leading to podiatric conditions in adulthood. The aim of this study was to assess the changes in morphological measurements of the feet of boys and girls during childhood and adolescence. METHODS: A total of 1678 Ecuadorian children aged 8 to 17 years participated in the study. The length, width, and height of the foot were analyzed using a 3D scanner to obtain the arch height ratio for the diagnosis of pediatric flat foot. RESULTS: Statistical differences were observed for lengths, widths, and perimeters of the foot in boys aged 5 to 15-16 years and girls aged 5 to 12-13 years. Differences in the height of the navicular bone were found in all age groups, with changes from 2.8 to 4.1% in boys and from 1.3 to 1.5% in girls. The greatest differences between boys and girls of the same age were found at 14 years old onwards. The highest prevalence of flat foot was found in 8-year-old girls (64.9%) and in 12-year-old boys (82.5%). CONCLUSIONS: The feet of Ecuadorian children develop progressively during childhood and adolescence. Boys presented with longer and wider feet than girls of the same age. The highest prevalence of flat foot was found in 12-year-old boys and 8-year-old girls.

Basic Principles of Flow Cytometer Operation: The Make your Own Flow Cytometer.

Flow cytometry is a critical technology for biomedical analysis and is an essential component of almost any study of the immune system. Widespread usage and increasing instrument complexity have, however, led to increasing neglect of education in their basic operating principles, a common situation with many technologies. This chapter describes the basics of flow cytometer operation using the Make Your Own Flow Cytometer ( https://www.cytometryworks.com ), a working cytometer than can be assembled by students into a functional instrument. This project and others like it is seeing widespread usage in biomedical education and can serve as models for like-minded investigators who wish to build their own systems. They also provide a good mechanism to introduce the key operational principles of flow cytometry as illustrated here.

Objective evaluation of changes in serum transmittance over time using a portable color digitizer.

Forensic pathologists empirically understand that postmortem changes can decrease serum transparency and change its color. Such changes are potential indicators for estimating postmortem intervals; however, reports on color changes focusing on postmortem changes in serum are scarce. To elucidate the effect of postmortem intervals on serum levels, we quantitatively evaluated and investigated the relationship between serum color and time using venous blood samples obtained from three healthy male volunteers. The serum samples were separated at 0 (1 h), 1, 2, 3, 4, 7, 10, 16, 21, and 28 days of storage. Serum transmittance and color were measured using a portable color digitizer and a custom-made measurement tool, respectively. Additionally, serum sodium (Na) and potassium (K) concentrations were measured. Serum transmittance showed a logistic curve-like decrease from 0.652 ± 0.016 (0 days) to 0.101 ± 0.014 (28 days) over time. The color changed from greenish yellow (dominant wavelength: 574.4 ± 0.63 nm) to reddish orange (603.97 ± 1.31 nm). Serum Na concentration decreased, whereas serum K concentration increased along the logistic curve. Strong (0.89, p < 0.001) and inverse correlations (-0.93, p < 0.001) were observed between the serum transmittance decrease and the Na concentration decrease and the K concentration increase, respectively. Serum transmittance decreased over time, indicating a transition from bright to dark. Moreover, a strong correlation was observed between serum transmittance and electrolytes, indicating a relationship between time course, serum transmittance, and electrolytes. These findings may contribute to the estimation of postmortem intervals in the future.

Does calibration pose improve scapular kinematic repeatability in functional tasks?

Tracking scapular motion can be challenging. More research is needed to determine the best practices for scapular measurement in multi-planar tasks. The purpose of this study was to compare the repeatability of scapular kinematics during a functional task protocol calculated from different calibration procedures. It was hypothesized that select poses would improve repeatability in specific tasks. The torso, humerus, and scapula were tracked with optical motion capture in two sessions for ten pain-free participants. Scapular calibrations were completed in five poses: neutral, maximum elevation, 90° abduction, hand to contralateral shoulder, and hand to back. Each participant completed eight functional tasks (Comb Hair, Wash Axilla, Tie Apron, Overhead Reach, Side Reach, Forward Transfer, Floor Lift, Overhead Lift). Scapular angles were calculated with five different calibration procedures and extracted at 30° increments of humeral elevation in each task. Mean difference, limits of agreement, intraclass correlations, and minimal detectable change (MDC) were calculated for each task and elevation level. The inclusion of different calibration poses did not markedly improve outcomes over the maximum elevation double calibration for most tasks. Using this calibration procedure, median MDCs were 10.0° for upward rotation, 13.7° for internal rotation, and 9.8° for tilt.

Activity standardization of 99mTc by digitizer-based 4πce(LS)-γ and 4πce(PC)-γ coincidence counting.

An aqueous solution of 99mTc was standardized by means of 4πce(LS)-γ and 4πce(PC)-γ coincidence counting. The activity concentration was obtained by efficiency extrapolation relying on four different variation techniques. In both setups, fast digitizers were used for data acquisition. Detected events were recorded in list mode format, and their coincidence relationship was analyzed in the subsequent offline analysis. The combined result was used to participate in an international comparison using the Transfer Instrument of the International Reference System.

Pankun: A New Generation of Broadband Ocean Bottom Seismograph.

This paper presents a new broadband ocean bottom seismograph (OBS) developed by the SUSTech OBS lab for passive-source seafloor seismic observations. This instrument, called Pankun, has several key features that set it apart from traditional OBS instruments. In addition to the seismometer-separated scheme, these features include a unique shielding structure to minimize current-induced noise, a compact gimbal for accurate leveling, and low power consumption for extended operation on the seafloor. The design and testing of Pankun's primary components are thoroughly described in this paper. The instrument has been successfully tested in the South China Sea, demonstrating its ability to record high-quality seismic data. The anti-current shielding structure of Pankun OBS has the potential to improve low-frequency signals, particularly on the horizontal components, in seafloor seismic data.

Test of a digitizer to process the pulse signal from the 3 photomultiplier tubes of a TDCR liquid scintillation counter.

The BIPM is developing a new service for international key comparisons in radionuclide metrology. The system, called ESIR, is based on a liquid scintillation counter using the Triple-to-Double Coincidence Ratio (TDCR) technique. The aim is to produce an international reference that can be reproduced over several decades of time in order to compare the calibration capabilities of National Metrology Institutes (NMIs). The maintainability of the electronics performing the signal processing is a challenge. To ensure the long-term sustainability of the electronics, the strategy is to set up redundant systems including at least one digital electronics module. The analogue modules developed in the 1990s and 2000s are less and less maintained and digital electronics are increasingly available on the market. In this context, a digitizer was tested and its suitability for the TDCR measurements compared to the currently used module based on an analogue front-end. This first implementation directly linking the photomultiplier anode to the CAEN digitizer without any analogue preconditioning shows a significant loss of detection efficiency and a lower signal to noise ratio observed on distributions of single photoelectrons. Although the TDCR method can correct for these efficiency losses, the loss of symmetry between the channels is too great to provide a sufficiently robust measurement. The use of low-pass filters upstream of the ADC will be considered to make this digital measurement system more reliable.

Absolute measurement of surface particle emission rates from α and β plane sources using a digitizer / 中国辐射卫生

Objective@#To prove the validity and accuracy of the digitizer instead of the conventional electronics plug-in for radionuclide measurement.@*Methods@# Based on a large-area flow-gas multi-wire proportional counter for 2πα and 2πβ surface particle emission rate measurement, the DT5730 digital waveform sampler developed by CAEN was used for waveform signal acquisition, amplitude analysis, and data processing of the α-plane source 241Am and the β-plane source nuclides 14C, 36Cl, and 90Sr-90Y of different energies.@*Results@#The deviations between the α and β surface particle emission rate results obtained after dead time and background corrections and the measurements obtained based on the plug-in calibrator were all within 0.6%, within the uncertainty range, under consistent experimental conditions such as electronics threshold and high pressure.@*Conclusion@#The digitizer is an effective alternative to conventional electronics plug-ins for α and β signal acquisition and processing and the accurate measurement of α and β emission rates.

Development of a portable TDCR system at NIM, China.

In order to meet the demand of on-site measurement for radionuclides, a portable liquid scintillation TDCR system was developed at National Institute of Metrology (NIM), China. The system consists small size TDCR counter for the measurement of liquid scintillation sources, and digital electronics for pulse signal processing. The optical chamber adopts Teflon material with high diffuse reflection efficiency. Two independent signal processing solutions were used here for TDCR counting. One employed the on-line TDCR solution based on FPGA counting module named TDCR-DMCA, and the other adopted the off-line TDCR solution based on a stand-alone desktop digitizer of CAEN. Two solutions are applied to perform coincidence, dead-time and counting operations follow by MAC3 logic. The performance of the TDCR counting system was tested in benchmark comparison with the traditional custom-built TDCR counting system at NIM through activity measurements of 3H, 14C. Good agreement between these two systems was observed.

Comparison of several Li doped scintillators for measurement of neutron and γ radiation integral quantities.

Five types of scintillators for parallel detection of neutrons and γ were tested for their pulse shape discrimination ability. All detectors are based on 6Li (n,alpha)3H reaction. LiI, ZnS and polystyrene were used as scintillators. Tests were performed at different neutron and γ mixed fields (AmBe, Cf) using a small Hamamatsu photomultiplier and a Picoscope digitizer. A polystyrene-based ZnS + LiF detector was proven to be the most suitable for neutron-γ separation and similar sensitivity for both types of radiation to construct a single device to measure integral quantities neutrons and γ (fluence, ambient dose equivalent) in parallel. The ZnS + LiF detector based on plexiglass, is in principle useable also, but has low sensitivity to γ radiation. The tested Li glass or LiI crystal does not have the ability to separate neutron and γ. With amplitude discrimination it can be used as a neutron detector for a much simpler probe for a Bonner spectrometer.

Kinematic analysis of handwriting movements and pencil grip patterns in children with low vision.

PURPOSE: Handwriting skills are important for the academic life of children and the lack of visual-motor performance leads to writing problems in children with low vision. This study aims to reveal handwriting kinematics and pencil grip features in children with low vision by means of a novel method. MATERIALS AND METHODS: 18 children with low vision (mean age: 9.83 ± 1.54 years) and 18 children with typical development (mean age: 9.83 ± 1.62 years) were included in the study. Children performed a sentence writing task on a digitizer tablet. During the task, the writing hand of children was photographed to analyze pencil grip patterns. RESULTS: Children with low vision performed greater stroke size except for the vertical size, slower writing speed, more dysfluent movements, and less pen pressure than children with typical development. However, participants preferred mature pencil grip patterns and had high grip scores independent from the diagnosis. CONCLUSIONS: The findings indicate that children with low vision have difficulties in handwriting in terms of spatial and temporal features. These results would be important for interventions to develop specific programs on writing skills to support their educational life.

Measurement error using a SeeMaLab structured light 3D scanner against a Microscribe 3D digitizer.

BACKGROUND: Geometric morphometrics is a powerful approach to capture and quantify morphological shape variation. Both 3D digitizer arms and structured light surface scanners are portable, easy to use, and relatively cheap, which makes these two capturing devices obvious choices for geometric morphometrics. While digitizer arms have been the "gold standard", benefits of having full 3D models are manifold. We assessed the measurement error and investigate bias associated with the use of an open-source, high-resolution structured light scanner called SeeMaLab against the popular Microscribe 3D digitizer arm. METHODOLOGY: The analyses were based on 22 grey seal (Halichoerus grypus) skulls. 31 fixed anatomical landmarks were annotated both directly using a Microscribe 3D digitizer and on reconstructed 3D digital models created from structured light surface scans. Each skull was scanned twice. Two operators annotated the landmarks, each twice on all the skulls and 3D models, allowing for the investigation of multiple sources of measurement error. We performed multiple Procrustes ANOVAs to compare the two devices in terms of within- and between-operator error, to quantify the measurement error induced by device, to compare between-device error with other sources of variation, and to assess the level of scanning-related error. We investigated the presence of general shape bias due to device and operator. RESULTS: Similar precision was obtained with both devices. If landmarks that were identified as less clearly defined and thus harder to place were omitted, the scanner pipeline would achieve higher precision than the digitizer. Between-operator error was biased and seemed to be smaller when using the scanner pipeline. There were systematic differences between devices, which was mainly driven by landmarks less clearly defined. The factors device, operator and landmark replica were all statistically significant and of similar size, but were minor sources of total shape variation, compared to the biological variation among grey seal skulls. The scanning-related error was small compared to all other error sources. CONCLUSIONS: As the scanner showed precision similar to the digitizer, a scanner should be used if the advantages of obtaining detailed 3D models of a specimen are desired. To obtain high precision, a pre-study should be conducted to identify difficult landmarks. Due to the observed bias, data from different devices and/or operators should not be combined when the expected biological variation is small, without testing the landmarks for repeatability across platforms and operators. For any study necessitating the combination of landmark measurements from different operators, the scanner pipeline will be better suited. The small scanning-related error indicates that by following the same scanning protocol, different operators can be involved in the scanning process without introducing significant error.

Gamma-ray spectroscopy with anode pulses of NaI(Tl) detector using a low-cost digitizer system.

Recently, digital gamma-ray spectroscopy employing low-cost and publicly available (Commercial off the shelf) digitizers has been frequently used in different studies worldwide. In this paper, we considered the digital methods for gamma-ray spectroscopy in which the anode pulses of the photomultiplier tube (PMT) output in a NaI(Tl) scintillation detector were immediately digitized by a PC sound card. We introduced and developed the methods for gamma-ray spectroscopy of microCurie gamma-ray sources by a sampling rate of 96 kHz. First, at low count rates, the pulse arrival time was determined directly by the raw waveform, and the gamma-ray spectrum was obtained by summing the corresponding values in the samples per pulse. In addition, the gamma-ray spectrum was obtained by an enhanced sampling rate waveform and the pulse arrival time was determined by employing the digital constant fraction discrimination (DCFD) method, where each pulse area was achievable by summing the corresponding values of pulse samples. On the other hand, fitting the appropriate model function on the pulses and obtaining the fitted pulse area were undertaken for gamma-ray spectroscopy. To this end, a non-iterative algorithm to fast fit the Gaussian model function was improved. Moreover, the pile-up correction was performed at different count rates employing the Maximum Likelihood Estimation (MLE) method and Gaussian model function. Also, an approximate method for solving the high run time challenge was identified in the MLE method for long-time waveforms. To reject the pile-up events, a method was introduced based on the calculation of the full-width at half maximum pulses. By applying the proposed rejection method, we achieved an energy resolution of 6.2% at 663 keV gamma-rays and a count rate of 5.3 kcps.

Environmental Factors as a Cause of Differences in the Feet of Ecuadorian Children and Its Relation to Their Footwear.

The objective of this study was to analyze the differences in foot measurements of Ecuadorian children according to their geographical location of residence, taking into account climatic differences (1). A total of 1662 children (2) participated in the study. Three groups were established: coast, mountains and amazonia. The type of footwear (3) used was recorded and the lengths, widths, perimeters, heights and angles of both (4) feet were analyzed with a 3D foot digitizer (5). The variable 'fitting of the foot to footwear' was also obtained. Children living in coastal areas presented greater lengths, widths, perimeters and heights compared to those living in the mountain (p > 0.001) and amazonia (p < 0.001) between ages 5 to 13. Mountain residents showed a greater first toe angle than coast residents (p > 0.001) aged 8 to 17. Children used shoes smaller than required by their foot length (p < 0.01). Ecuadorian children from the coast presented longer and wider feet with higher foot arches, whilst those from mountains presented greater first toe angle. The studied sample used footwear up to one size smaller than the size corresponding to their foot length. The fitting and type of footwear used according to climatic differences could be interfering with normal foot development.

Three-dimensional surface scanning methods in osteology: A topographical and geometric morphometric comparison.

OBJECTIVES: Three-dimensional (3D) data collected by structured light scanners, photogrammetry, and computed tomography (CT) scans are increasingly combined in joint analyses, even though the scanning techniques and reconstruction software differ considerably. The aim of the present study was to compare the quality and accuracy of surface models and landmark data obtained from modern clinical CT scanning, 3D structured light scanner, photogrammetry, and MicroScribe digitizer. MATERIAL AND METHODS: We tested 13 different photogrammetric software tools and compared surface models obtained by different methods for four articulated human pelves in a topographical analysis. We also measured a set of 219 landmarks and semilandmarks twice on every surface as well as directly on the dry bones with a MicroScribe digitizer. RESULTS: Only one photogrammetric software package yielded surface models of the complete pelves that could be used for further analysis. Despite the complex pelvic anatomy, all three methods (CT scanning, 3D structured light scanning, photogrammetry) yielded similar surface representations with average deviations among the surface models between 100 and 200 µm. A geometric morphometric analysis of the measured landmarks showed that the different scanning methods yielded similar shape variables, but data acquisition via MicroScribe digitizer was most prone to error. DISCUSSION: We demonstrated that three-dimensional models obtained by different methods can be combined in a single analysis. Photogrammetry proved to be a cheap, quick, and accurate method to generate 3D surface models at useful resolutions, but photogrammetry software packages differ enormously in quality.

Standardisation of 85Sr with digital anticoincidence counting and half-life determination of the 514 keV level of 85Rb.

The activity of a 85Sr solution was determined by means of fully digital 4πß(LS)-γ anticoincidence counting. The measurements were carried out in a custom-built, combined TDCR / 4πß(LS)-γ coincidence system, utilising a commercially available CAEN N6751C digitizer. The analysis of the experimental data, collected in list-mode format, was performed off-line by using the SoftKAM computer code developed at PTB. The data were also used to determine the half-life of the 514 keV level of 85Rb which was found to be (1020.2 ± 6.0) ns.

Digitalized spiral drawing in Parkinson's disease: A tool for evaluating beyond the written trace.

One of the current scientific challenges is to propose novel tools and tasks designed to identify new motor biomarkers in Parkinson's disease (PD). Among these, a focus has placed on drawing tasks. Independently from clinical ratings, this study aimed to evaluate the pen movement and holding in digitalized spiral drawing in individuals with PD without and with medical treatment and in healthy controls. A three-step data-driven analysis was conducted. First, the effects of spatial and temporal constraints on several variables were determined. Second, the relationship between handedness and dominance of PD symptoms was investigated for the most relevant variables. Finally, a third analysis was conducted to assess the occurrence of changes associated with PD. The first analysis revealed that the number of velocity peaks and pen altitude variations were the most relevant variables in spiral drawing for evaluating the effect of the disease and medication. The second analysis revealed that the effect of medication was present for the movement fluency only, when spirals with spatial constraints were produced at a spontaneous speed by the hand on the side of dominant PD signs. Finally, the third analysis showed that the effect of medication was greater at the beginning of drawing than at the end. Digitalized spiral drawing makes it possible to observe precisely when the kinematic changes related to the disease occur during the task. Such a simple and quick task might be of great relevance to contribute to the diagnosis and follow-up of PD.

Sistema de adquisición de datos en tiempo real para un detector modular de neutrones en los experimentos con el RIBRAS / A real time pulse processing Data acquisition for neutron modular detector on RIBRAS experiments

Resumen Con la finalidad de maximizar las posibilidades experimentales en el estudio de los núcleos exóticos utilizando el haz del sistema "Radioactive Ion Beams in Brasil" (RIBRAS), fue desarrollado un sistema modular de detectores centelleantes orgánicos con buena eficiencia y amplio ángulo sólido, conocido como Pared de Neutrones. La detección de los neutrones emitidos en coincidencia con los fragmentos de reacción incrementa las posibilidades experimentales y constituye una de las técnicas más usadas en el campo de la Astrofísica Nuclear. El obsoleto sistema de adquisición de datos de la Pared de Neutrones debe ser remplazado por un sistema basado en módulos del patrón Versa Module Euro Card (VME). El nuevo esquema será definido para incluir el arreglo de detectores de bandas para partículas cargadas y la Pared de Neutrones con el máximo de eficiencia de adquisición, sin tiempo muerto, con selección de datos y sincronización de eventos. Los módulos digitalizadores garantizan tareas como la supresión de ceros y la saturación en la lectura de la señal. Adicionando tarjetas FPGA (field programmable gate array) a la adquisición de datos se garantiza el procesamiento pre y post-algorítmico de los datos.

Abstract In order to potentiate the experiments for studying the exotic nuclei with Brazil Radioactive Ion Beam (RIBRAS), a modular organic scintillation detector (Neutron Wall), with good efficiency and extended solid angle was developed. The detection of neutrons emitted in coincidence with the reaction fragments increases the experimental possibilities and represents one of the most popular techniques in the Nuclear Astrophysics field. The data acquisition system used for the Neutron Wall is obsolete and should be replaced by Versa Module Euro Card Data Acquisition modules. The new scheme will be designed to include the Strip Array and Neutron Wall detectors with maximum readout efficiency, no dead time, data selection and event synchronization. The digitizer modules provide features like zero suppressed readout and overflow suppression. Zero suppression, once enabled, prevents conversion of value, which is lower than user defined threshold. Adding FPGA (field programmable gate array) cards to data acquisition provides pre- and post-algorithmic processing on data.

Accuracy of multi-unit implant impression: traditional techniques versus a digital procedure.

OBJECTIVES: The objective of this study was to evaluate the accuracy of different impression techniques on multiple implants. MATERIAL AND METHODS: A master cast simulating a jaw with four implants was used. Eight impression techniques were tested: open tray-polyether#1, open tray plus splint of impression copings with acrylic resin-polyether#1, closed tray-polyether#1, open tray-polyether#2, open tray-splint-polyether#2, closed tray-polyether#2, open tray-impression plaster, and digital impression (DI). Five impressions of the master cast were taken with each traditional impression (TI) technique, pouring 35 sample casts. Three different clinicians took 5 DI each (n = 15). A three-dimensional coordinate measurement machine (CMM) was used to measure implant angulation and inter-implant distances on TI casts. TI data and DI Standard Tessellation Language datasets were compared with the master cast. The best and the worst impressions made with TI and DI were selected to fabricate four milled titanium frameworks. Passive fit was evaluated through Sheffield test, screwing each framework on the master cast. Gaps between framework-implant analogs were measured through a stereomicroscope (×40 magnification). RESULTS: Statistically significant differences in accuracy were found comparing the different impression techniques by CMM (p < 0.01). DI performed the best, while TI techniques revealed a greater variability in the results. Sheffield test revealed a mean gap of 0.022 ± 0.023 mm (the best TI), 0.063 ± 0.059 mm (the worst TI), 0.015 ± 0.011 mm (the best DI), and 0.019 ± 0.015 mm (the worst DI). CONCLUSIONS: Within the limits of this in vitro study, the digital impression showed better accuracy compared to conventional impressioning. CLINICAL RELEVANCE: The digital impression might offer a viable alternative to traditional impressions for fabrication of full-arch implant-supported prostheses with satisfactory passive fit.

Error in geometric morphometric data collection: Combining data from multiple sources.

OBJECTIVES: This study compares two- and three-dimensional morphometric data to determine the extent to which intra- and interobserver and intermethod error influence the outcomes of statistical analyses. MATERIALS AND METHODS: Data were collected five times for each method and observer on 14 anthropoid crania using calipers, a MicroScribe, and 3D models created from NextEngine and microCT scans. ANOVA models were used to examine variance in the linear data at the level of genus, species, specimen, observer, method, and trial. Three-dimensional data were analyzed using geometric morphometric methods; principal components analysis was employed to examine how trials of all specimens were distributed in morphospace and Procrustes distances among trials were calculated and used to generate UPGMA trees to explore whether all trials of the same individual grouped together regardless of observer or method. RESULTS: Most variance in the linear data was at the genus level, with greater variance at the observer than method levels. In the 3D data, interobserver and intermethod error were similar to intraspecific distances among Callicebus cupreus individuals, with interobserver error being higher than intermethod error. Generally, taxa separate well in morphospace, with different trials of the same specimen typically grouping together. However, trials of individuals in the same species overlapped substantially with one another. CONCLUSION: Researchers should be cautious when compiling data from multiple methods and/or observers, especially if analyses are focused on intraspecific variation or closely related species, as in these cases, patterns among individuals may be obscured by interobserver and intermethod error. Conducting interobserver and intermethod reliability assessments prior to the collection of data is recommended.