An Arbitrarily High Order and Asymptotic Preserving Kinetic Scheme in Compressible Fluid Dynamic.

We present a class of arbitrarily high order fully explicit kinetic numerical methods in compressible fluid dynamics, both in time and space, which include the relaxation schemes by Jin and Xin. These methods can use the CFL number larger or equal to unity on regular Cartesian meshes for the multi-dimensional case. These kinetic models depend on a small parameter that can be seen as a "Knudsen" number. The method is asymptotic preserving in this Knudsen number. Also, the computational costs of the method are of the same order of a fully explicit scheme. This work is the extension of Abgrall et al. (2022) [3] to multi-dimensional systems. We have assessed our method on several problems for two-dimensional scalar problems and Euler equations and the scheme has proven to be robust and to achieve the theoretically predicted high order of accuracy on smooth solutions.

Effects of lipid extraction on stable isotope ratios of carbon and nitrogen in muscles of freshwater fish.

The extraction of lipids by the Folch method from the muscles of all the fish studied led to statistically significant differences in the values of δ15N. At the same time, lipid extraction led to a statistically significant increase in δ13C in pike and roach, and to a statistically insignificant decrease in δ13C in perch and bream. Thus, lipid extraction cannot serve as a universal method of sample preparation for the analysis of the isotopic composition of carbon (13C/12C) and nitrogen (15N/14N) in fish muscles. The differences between the δ13C values in the samples before and after lipid extraction were statistically investigated by different models. It is shown that mathematical correction method models can be used, but the results are depending on the fish types.

Accurate correction model of blood potassium concentration in hemolytic specimens.

BACKGROUND AND AIMS: The results of blood potassium can be seriously affected by specimen hemolysis which may interfere with clinicians' interpretation of test results. Redrawing blood and retesting may delay treatment time and it is not feasible for critically ill patients with difficulty in specimen collection. Therefore, it is significant to establish a mathematical model that can quickly correct the blood potassium concentration of hemolytic specimens. MATERIALS AND METHODS: The residual blood samples from 107 patients at Peking University Third Hospital were collected to establish potassium correction model. Samples with different hemolysis indexes were obtained by ultrasonic crushing method. Blood potassium correction models of hemolysis specimens were established by linear regression and curve fitting using SPSS and MATLAB, respectively. In addition, blood samples from another 85 patients were used to verify the accuracy of the models and determine the optimal model. RESULTS: Variation of potassium (ΔK) was 0.003HI-0.03 (R2 = 0.9749) in linear regression model which had high correlation in ΔK and HI, and the correction formula was Kcorrection = Khemolysis-0.003 × HI + 0.03. Average rate of potassium change (αaverage) was 0.003 ± 0.0002 mmol/L in curve fitting model, and correction formula was Kcorrection = Khemolysis-0.003 × HI, and both men and women can use the same correction model. The accuracy of linear regression model was 96.5 %, and there was statistical difference between the verification results and the measured values (p < 0.05), while the accuracy of curve fitting model was 100 %, and there was no statistical difference between the verification results and the measured values (p = 0.552). The model was validated in an independent set of samples and all were within the TEa of 6 % and the accuracy of 100 %. CONCLUSIONS: Both linear regression and curve fitting models of potassium correction had high accuracy, and can effectively correct the potassium concentration of hemolytic specimens, while the curve fitting model have superior accuracy.

Variable Pivot Gait Based a Novel Dynamics Correction Method for Human Lower Limbs Model.

The rationality of gait analysis directly affects the dynamics of human lower limbs in the sagittal plane, and recent studies on gait stage redivision lack the stage when both feet are not in complete contact with the ground. This paper proposes a novel variable pivot gait, which includes the stage when the heel of one foot and the toe of the other are in contact with the ground and a dynamics correction method based on this gait. First, the relative motion data between the foot and the ground are measured by motion capture experiments, and then a variable pivot gait is proposed in terms of the pivot transformation between the foot and the ground. Second, the dynamics modeling is conducted based on the principle of mechanisms of human lower limbs in each stage of the variable pivot gait. Third, a dynamics correction method is proposed to correct the foot dynamics when the foot is not in complete contact with the ground. The experiment and simulation show that the variable pivot gait is consistent with the actual motion of the foot relative to the ground. The effectiveness of the dynamics correction method is proved by comparing dynamics results (hip, knee, and ankle moments) with previous studies. The variable pivot gait and the dynamics correction method can be applied to the human lower limbs and lower-limb robots, providing a new avenue.

Evaluating the Impact of Intracranial Volume Correction Approaches on the Quantification of Intracranial Structures in MRI: A Systematic Analysis.

BACKGROUND: In neuroscience, accurately quantifying individual brain regions in large cohorts is a challenge. Differences in intracranial structures can suggest functional differences, but they also reflect the effects of other factors. However, there is currently no standardized method for the correction of intracranial structure measurements. PURPOSE: To identify the optimal method to counteract the influence of total intracranial volume (TIV) and gender on the measurement of intracranial structures. STUDY TYPE: Prospective. POPULATION/SUBJECTS: One hundred forty-one healthy adult volunteers (70 male, mean age 21.8 ± 1.7 years). FIELD STRENGTH/SEQUENCE: T1-weighted 3D gradient-echo sequence at 3.0 T. ASSESSMENT: A radiologist with 5 years of work experience screened the raw images to exclude poor-quality images. Freesurfer then performed automated segmentation to obtain measurements of intracranial structures. Male-only, female-only, and TIV-matched sub-samples were created separately. Comparisons between the original data and these sub-samples were used to assess the effects of gender and TIV. Comparison the consistency between TIV-matched sample and corrected data that corrected by four methods: Proportion method, power-corrected proportion method, covariate regression method, and residual method. STATISTICAL TESTS: Cohen's d for examining group distribution disparities, t-tests for probing mean differences, correlation coefficients to assess the relationships between intracranial substructure measurements and TIV. Multiple comparison corrections were applied to the results. RESULTS: The correlation coefficients between TIV and the volumes of intracranial structures ranged from 0.033 to 0.883, with an average of 0.467. Thirty significant volume differences were found among 36 structures in the original sample, while no differences were observed in the TIV-matched sample. Among the four correction methods, the residual method had highest consistency (similarity 94.4%) with the TIV-matched group. DATA CONCLUSION: The variation in intracranial structure sizes between genders was largely attributable to TIV. The residual method offers a more accurate and effective approach for correcting the effects of TIV on intracranial structures. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 1.

Study on Calibration Method for the Count of Living Algal Cells Detection Based on Variable Fluorescence in Ballast Water.

In the monitoring the discharge of ballast water, the count of living algal cells is of utmost significant. Variable fluorescence, denoted as Fv, stands as an optimal parameter for photosynthetic fluorescence, efficiently charactering the living algal cells count, unaffected by the ballast waters' complex background fluorescence environment. This study deeply investigates the quantitative relationship between Fv and the count of living algal cells. Observations indicate that single cell fluorescence yield (abbreviated as SCF) varies significantly across different algae species, leading to considerable errors in quantifying living algal cell count in ballast water with unknown components using the calibration relationship between Fv and the cell count. Thus, correcting SCF prior to calibration becomes necessary. The paper proposes an innovative SCF correction method based on cell cross-sectional area and an eµ factor (where µ is the expected value of the functional absorption cross-section of PSII) This method mitigates the influence of cell size and species differences on quantifying the living algal cell count. Correction operation trials revealed that dividing the SCF measurement by cell cross-sectional area and multiplying by eµ enhanced the correction effect. Comparative experiments demonstrated marked improvement: Relative errors (REs) for Chlorella pyrenoidosa and Chlorella marine, both belonging to the Chlorophyta group, fell from 92.1% and 90.6% to 37.2% and 9.5% respectively post-correction. Similarly, REs for Thalassiosira weissflogii and Nitzschia closterium minutissima, from the Bacillariophyta group, decreased from 74.7% and 68.1% to 14.3% and 19.1% respectively. The RE of Peridinium from the Pyrrophyta group dropped from 28.4% to 12.1%. The results underscore the effectiveness of cell cross-sectional area and eµ in correcting SCF, thus offering a novel correction method for swift and precise measurement of living algal cell count in ballast water, based on variable fluorescence.

The effect of background noise and its removal on the analysis of single-cell expression data.

BACKGROUND: In droplet-based single-cell and single-nucleus RNA-seq experiments, not all reads associated with one cell barcode originate from the encapsulated cell. Such background noise is attributed to spillage from cell-free ambient RNA or barcode swapping events. RESULTS: Here, we characterize this background noise exemplified by three scRNA-seq and two snRNA-seq replicates of mouse kidneys. For each experiment, cells from two mouse subspecies are pooled, allowing to identify cross-genotype contaminating molecules and thus profile background noise. Background noise is highly variable across replicates and cells, making up on average 3-35% of the total counts (UMIs) per cell and we find that noise levels are directly proportional to the specificity and detectability of marker genes. In search of the source of background noise, we find multiple lines of evidence that the majority of background molecules originates from ambient RNA. Finally, we use our genotype-based estimates to evaluate the performance of three methods (CellBender, DecontX, SoupX) that are designed to quantify and remove background noise. We find that CellBender provides the most precise estimates of background noise levels and also yields the highest improvement for marker gene detection. By contrast, clustering and classification of cells are fairly robust towards background noise and only small improvements can be achieved by background removal that may come at the cost of distortions in fine structure. CONCLUSIONS: Our findings help to better understand the extent, sources and impact of background noise in single-cell experiments and provide guidance on how to deal with it.

Comparison of different QT correction methods for nonclinical safety assessment in ketamine-anesthetized Indian rhesus monkeys (Macaca mulatta).

Rhesus monkeys are a non-rodent species employed in the preclinical safety evaluation of pharmaceuticals and biologics. These nonhuman primate species have been increasingly used in biomedical research because of the similarity in their ionic mechanisms of repolarization with humans. Heart rate and QT interval are two primary endpoints in determining the pro-arrhythmic risk of drugs. As heart rate and QT interval have an inverse relationship, any change in heart rate causes a subsequent change in QT interval. This warrants for calculation of a corrected QT interval. This study aimed to identify an appropriate formula that best corrected QT for change in heart rate. We employed seven formulas based on source-species type, clinical relevance, and requirements of various international regulatory guidelines. Data showed that corrected QT interval values varied drastically for different correction formulas. Equations were compared on their slope values based on QTc versus RR plots. The rank order of the slope for different formulas was (closest to farthest from zero) QTcNAK, QTcHAS, QTcBZT, QTcFRD, QTcVDW, QTcHDG, and QTcFRM. QTcNAK emerged to be the best correcting formula in this study. It showed the least correlation with the RR interval (r = -0.01) and displayed no significant difference amongst the sexes. As there is no universally recognized formula for preclinical use, the authors recommend developing a best-case scenario model for specific study designs and individual organizations. The data from this research will be helpful in deciding an appropriate QT correction formula for the safety assessment of new pharmaceuticals and biologics.

A strategy to reduce the effect of organic matter on fluorescence intensity for improving the detection accuracy of polycyclic aromatic hydrocarbons in soil.

Fluorescence spectroscopy has been used for rapid detection of PAHs in soil, but soil organic matter (SOM) produces strong interference to the fluorescence intensity of PAHs, which restricts the application of fluorescence spectroscopy for rapid detection of PAHs in soil. A correction method of reducing the interference of SOM on PAHs fluorescence intensity was proposed combining fluorescence and near-infrared (NIR) spectroscopy. Six soil samples with different concentrations of humic acid (HA) at a given phenanthrene concentration (5 mg/g) were prepared and scanned for obtaining the fluorescence and NIR diffuse reflectance spectra. The spectral data showed that the fluorescence intensity and NIR diffuse reflectance had an approximate trend with the change of HA concentration. It was found that the NIR diffuse reflection at 4672 cm-1 as a calibration factor could effectively reduce the interference of HA on the fluorescence intensity of phenanthrene. Subsequently, a standard curve for the quantitative analysis of phenanthrene in soil was established based on the fluorescence intensity before and after calibration. For the unknown samples, the predicted average relative errors of the standard curves before and after calibration were 27.46 % and 9.00 %, respectively. The results showed that the proposed correction method could reduce the interference of HA on the quantitative analysis of PAHs, and provide a reference for eliminating the interference constraint of fluorescence spectroscopy technique for rapid real-time detection of PAHs in soil.

CH4/C2H6 dual gas sensing system using a single mid-infrared laser.

Methane (CH4) and ethane (C2H6) dual gas sensor with low system complexity and strong stability is proposed. The correction method based on absorbance spectrum is applied, and the cross-interference of C2H6 to CH4 is eliminated. In the single gas concentration measurement, linear fitting is performed between the absorbance and concentration of CH4 and C2H6, and the correlation coefficients of R2 = 0.99959 and R2 = 0.99994 are obtained respectively, which proves that the accuracy of the dual gas sensor is robust. In the dual gas concentration measurement, we carry out continuous measurement of five mixed gases and a long-term measurement of a mixture of gases, which verifies that our sensor has the fast response speed and strong stability. The minimum detectable column densities of 0.62 ppm·m for CH4 and 0.1 ppm·m for C2H6 are achieved, respectively. The CH4/C2H6 dual gas sensor assisted by the correction method has high sensitivity and strong robustness to cross-interference, and has great potential for application in various scenarios.

Salinity-dependent aquatic life criteria of inorganic mercury in coastal water and its ecological risk assessment.

Mercury (Hg) is one of the most toxic pollutants to aquatic organisms. The influence of salinity on Hg toxicity, an important factor restricting the development of global marine aquatic life criteria (ALC), is unclear. Therefore, mercury toxicity data were corrected based on salinity using the aggregate slope method, and the ALC values were derived. Short-term aquatic life criteria (SALC) and long-term aquatic life criteria (LALC) were derived using the species sensitivity distribution method based on Log-logistic, Log-normal, Burr III, Gumbel, and Weibull models. The hazard quotient (HQ) and joint probability curve (JPC) methods were used to evaluate the ecological risk of Hg in the coastal waters of China. The results showed that the SALC and LALC of Hg in the coastal waters of China were 2.21 and 0.54 µg/L. The toxicity data and salinity were positively correlated for Chordate and Arthropoda and negatively correlated for Mollusca. The SALC values increased by approximately 75%, with salinities ranging from 10 to 20 ppt. A slight peak in the SALC at mid-salinities was also observed. The ecological risk assessment of Hg in China's coastal waters showed that attention should be paid to Hg pollution in the Bohai Sea and East China Sea, especially the ecological risk of Hg to crustacean organisms. This study could promote the development of water quality criteria for coastal waters and provide a technical reference for mercury management in the coastal waters of China.

Establishment of a new strategy to correct the interference of chyle blood on the detection of hemoglobin and mean red blood cell hemoglobin concentration / 中华检验医学杂志

Objective:To establish a new strategy for rapid correction of the interference of chyle blood on hemoglobin (HGB) and related indexes by reticulocyte (RET) channel research parameters (HGB-O, MCHC-O) from automatic hematological analyzer.Methods:With the diagnostic experimental design, a total of 90 impatient samples were sequential picked from Fuwai Hospital, which had routine blood testing from June 1 to July 31, 2021. The selected samples were free of hemolysis, jaundice, chylo. The age of the patients was (49.2±5.7) years, with 47 males and 43 females. Three different contents(25, 50, 75 μl) of fat emulsion injection were used to replace plasma in equal amounts to prepare chyle blood samples with mild, medium and heavy degrees of average red blood cell hemoglobin concentration (MCHC). The research parameters (HGB-O, MCHC-O) obtained by the RET channel detection of the automatic blood analyzer were used as the corrected HGB and its related index values (RET method), and the original values (the detection values before adding fat emulsion) and the formula correction values were paired with t-test or Wilcoxon signed rank test, single factor analysis of variance or Kruskal-Wallis rank-sum test, Bland-Altman and correlation analysis to evaluate the correction effect of RET method.Results:There was no significant difference ( H=0.035, P=0.983; H=0.097, P=0.953; H=0.112, P=0.945) between the RET correction values of HGB (g/L) [104.0(83.8, 132.8), 109.0(87.78, 128.25), 104.0(87.8, 131.8)] and the original values [104.0(83.0, 133.0), 107.5(86.75, 129.25), 103.5(85.8, 131.3)] and the formula correction values [104.0(84.0, 133.8), 106.0(86.75, 131.25), 102.5(86.8, 131.3)] in the samples of chythemia with varying degrees of MCHC (g/L) elevation; meanwhile, the RET correction values [366.5(325.8, 341.5), 333.5(323.8, 340.0), 333.5(327.0, 341.25)] and the original values [336.0(324.8, 342.0), 333.0(323.5, 342.3), 332.0(326.75, 340.5)] and the formula correction values [333.5(323.5, 343.3), 331.0(321.0, 338.3), 329.5(325.25, 337.25)] were also not statistically significant ( H=0.049, P=0.976; H=3.149, P=0.207; H=0.883, P=0.643). The detection values of HGB and related indexes corrected by RET method were in good agreement with the original values [96.7% (29/30) of the points were within the 95% consistency limit], and the two were positively correlated (the correlation coefficients were all higher than 0.919, P<0.01). Conclusion:The RET method based on the research parameters of RET channel of automatic hematological analyzer can serve as a new strategy to correct the interference of chyle blood on the detection of HGB and related indexes.

Partial Verification Bias Correction Using Inverse Probability Bootstrap Sampling for Binary Diagnostic Tests.

In medical care, it is important to evaluate any new diagnostic test in the form of diagnostic accuracy studies. These new tests are compared to gold standard tests, where the performance of binary diagnostic tests is usually measured by sensitivity (Sn) and specificity (Sp). However, these accuracy measures are often biased owing to selective verification of the patients, known as partial verification bias (PVB). Inverse probability bootstrap (IPB) sampling is a general method to correct sampling bias in model-based analysis and produces debiased data for analysis. However, its utility in PVB correction has not been investigated before. The objective of this study was to investigate IPB in the context of PVB correction under the missing-at-random assumption for binary diagnostic tests. IPB was adapted for PVB correction, and tested and compared with existing methods using simulated and clinical data sets. The results indicated that IPB is accurate for Sn and Sp estimation as it showed low bias. However, IPB was less precise than existing methods as indicated by the higher standard error (SE). Despite this issue, it is recommended to use IPB when subsequent analysis with full data analytic methods is expected. Further studies must be conducted to reduce the SE.

Low Cost Three-Dimensional Programmed Mini-Pump Used in PCR.

Programmed mini-pumps play a significant role in various fields, such as chemistry, biology, and medicine, to transport a measured volume of liquid, especially in the current detection of COVID-19 with PCR. In view of the cost of the current automatic pipetting pump being higher, which is difficult to use in a regular lab, this paper designed and assembled a three-dimensional programmed mini-pump with the common parts and components, such as PLC controller, motor, microinjector, etc. With the weighting calibration before and after pipetting operation, the error of the pipette in 10 µL (0.2%), 2 µL (1.8%), and 1 µL (5.6%) can be obtained. Besides, the contrast test between three-dimensional programmed mini-pump and manual pipette was conducted with the ORF1ab and pGEM-3Zf (+) genes in qPCR. The results proved that the custom-made three-dimensional programmed mini-pump has a stronger reproducibility compared with manual pipette (ORF1ab: 24.06 ± 0.33 vs. 23.50 ± 0.58, p = 0.1014; pGEM-3Zf (+): 11.83.06 ± 0.24 vs. 11.50 ± 0.34, p = 0.8779). These results can lay the foundation for the functional, fast, and low-cost programmed mini-pump in PCR or other applications for trace measurements.

Recovery-Based Error Estimator for Natural Convection Equations Based on Defect-Correction Methods.

In this paper, we propose an adaptive defect-correction method for natural convection (NC) equations. A defect-correction method (DCM) is proposed for solving NC equations to overcome the convection dominance problem caused by a high Rayleigh number. To solve the large amount of computation and the discontinuity of the gradient of the numerical solution, we combine a new recovery-type posteriori estimator in view of the gradient recovery and superconvergent theory. The presented reliability and efficiency analysis shows that the true error can be effectively bounded by the recovery-based error estimator. Finally, the stability, accuracy and efficiency of the proposed method are confirmed by several numerical investigations.

Correcting for partial verification bias in diagnostic accuracy studies: A tutorial using R.

Diagnostic tests play a crucial role in medical care. Thus any new diagnostic tests must undergo a thorough evaluation. New diagnostic tests are evaluated in comparison with the respective gold standard tests. The performance of binary diagnostic tests is quantified by accuracy measures, with sensitivity and specificity being the most important measures. In any diagnostic accuracy study, the estimates of these measures are often biased owing to selective verification of the patients, which is referred to as partial verification bias. Several methods for correcting partial verification bias are available depending on the scale of the index test, target outcome, and missing data mechanism. However, these are not easily accessible to the researchers due to the complexity of the methods. This article aims to provide a brief overview of the methods available to correct for partial verification bias involving a binary diagnostic test and provide a practical tutorial on how to implement the methods using the statistical programming language R.

Source term determination with elastic plume bias correction.

Estimation of a source term, i.e. release rate, of atmospheric radionuclide emissions is of key interest for nuclear emergency response and further accident analysis. The source term estimate is, however, often very inaccurate due to biases in atmospheric transport and used meteorological analysis. We propose a method for atmospheric plume bias correction which uses not only concentrations modeled at a measuring site but also the information on concentration gradient from the neighborhood of each measuring site, i.e. information already available from the atmospheric transport model. To properly regularize the model, we propose an elastic model of the plume bias correction based on regularization with the use of known topology of the measurement network. The proposed plume bias correction method can be coupled with an arbitrary source term estimation algorithm and can be instantly applied to any other atmospheric release of hazardous material. We demonstrate the method in two real cases. First, we use data from the European Tracer Experiment to validate the methodology. Second, we use data from the 106Ru occurrence over Europe in 2017 to demonstrate the methodology in a more demanding case where agreement with state-of-the-art estimates is shown with much better reconstruction of measurements.

Baseline correction method for dynamic pressure gradient modulated comprehensive two-dimensional gas chromatography with flame ionization detection.

A baseline correction method is developed for comprehensive two-dimensional (2D) chromatography (GC × GC) with flame-ionization detection (FID) using dynamic pressure gradient modulation (DPGM). The DPGM-GC × GC-FID utilized porous layer open tubular (PLOT) columns in both dimensions to focus on light hydrocarbon separations. Since DPGM is nominally a stop-flow modulation technique, a rhythmic baseline disturbance is observed in the FID signal that cycles with the modulation period (PM). This baseline disturbance needs to be corrected to optimize trace analysis. The baseline correction method has three steps: collection of a background "blank" chromatogram and multiplying it by an optimized normalization factor, subtraction of the normalization-optimized background chromatogram from a sample chromatogram, and application of Savitzky-Golay smoothing. An alkane standard solution, containing pentane, hexane and heptane was used for method development, producing linear calibration curves (r2 > 0.991) over a broad concentration range (7.8 ppm - 4000 ppm). Further, the limit-of-detection (LOD) and limit-of-quantification (LOQ) were determined for pentane (LOD = 2.5 ppm, LOQ = 8.2 ppm), hexane (LOD = 0.9 ppm, LOQ = 3.0 ppm), and heptane (LOD = 1.9 ppm, LOQ = 6.4 ppm). A natural gas sample separation illustrated method applicability, whereby the DPGM produced a signal enhancement (SE) of 30 for isopentane, where SE is defined as the height of the tallest 2D peak in the modulated chromatogram for the analyte divided by the height of the unmodulated 1D peak. The 30-fold SE resulted in about a 10-fold improvement in the signal-to-noise ratio (S/N) for isopentane. Additional versatility of the baseline correction method for more complicated samples was demonstrated for an unleaded gasoline sample, which enabled the detection (and visual appearance) of trace components.

Bilateral Tibial Proximal Fractures Caused by Secondary Osteomalacia due to Autoimmune Polyendocrine Syndrome Type 2: A Case Report.

INTRODUCTION: Hypophosphatemic osteomalacia can be overlooked or confused with other musculoskeletal disorders due to the variety of associated clinical, laboratory, and radiographic findings. If osteomalacia is diagnosed early and the fractures are not displaced, they often heal with nutritional supplements, but, if they progress to displaced fractures, they may require surgical intervention. CASE REPORT: We present a case of secondary osteomalacia due to autoimmune polyendocrine syndrome Type 2 due to this condition, the patient developed bilateral tibial proximal fractures and her varus deformity had progressed. No clear indication of the timing for surgery for adults with osteomalacia has been reported. However, medical treatment improves the symptoms of osteomalacia and it is reported that in children, appropriate level of the serum phosphate (P) should be attained and maintained for the successful bone healing after osteotomy. Therefore, we prioritized pharmacological treatment and prescribed surgery after confirming that the value of serum phosphate P had been improved to recommended levels (2.5-3.5 mg/dl). We performed high tibial osteotomy for the right side and gradual correction by an external fixation for the left tibia, because of more severe deformation, and converted to an internal fixation to shorten the treatment period. During conversion, we performed the operation with a locking plate by the minimal invasive plate osteosynthesis method (MIPO). CONCLUSION: We conclude that the use of different deformity correction methods, depending on the degree of deformity, and the pharmacological treatment of osteomalacia may lead to favorable results.

How to compare knee kinetics at different walking speeds?

BACKGROUND: Walking speed is a confounding factor in biomechanical analyses of gait, but still many studies compare gait biomechanics at comfortable walking speed (CWS) that is likely to differ between groups or conditions. To identify gait deviation unrelated to walking speed, methods are needed to correct biomechanical data over the gait cycle for walking speed. RESEARCH QUESTION: How to compare knee kinetics over the gait cycle at different walking speeds? METHODS: 22 asymptomatic subjects walked on a dual-belt treadmill at CWS and 4 fixed speeds. Knee moments in sagittal (KFM) and frontal plane (KAM) were calculated via inverse dynamics. The net moment differences between CWS and fixed speed were expressed as a root-mean-square error (RMSE) normalized to the range of the variable. Two methods to correct for walking speed were compared. In method 1, KFM and KAM values were estimated based on interpolation between speeds at each percentage of the gait cycle. In method 2, principal component analysis was used to extract speed related features to reconstruct KFM and KAM at the speed of interest. The accuracy of both methods was tested using a leave-one-out cross validation. RESULTS: Walking speed influenced the magnitude and shape of KFM and KAM. To account for these speed influences using both methods, leave-one-out cross validation showed low normalized RMSE (< 5 %), with little difference between the two methods. RMSE for both reconstruction methods were up to 60 % lower than the RMSE between CWS and fixed speed. SIGNIFICANCE: Both methods could accurately correct knee kinetics over the gait cycle for the effects of walking speed. Walking speed dependency should be incorporated in each gait laboratory's reference dataset to be able to identify gait deviations unrelated to gait speed.