Calculation Of Reference Values Research Articles

External quality assessment programs of laboratory testresults conducted by the Central Center for Quality Researchin Laboratory Diagnostics in 2022

<br><b>Introduction:</b> In 2022, the Central Center for Quality Research in Laboratory Diagnosticsconducted 16 tests as part of seven programs for external assessment of the quality oflaboratory test results. As many as 1,437 medical diagnostic laboratories participated inthe programs. Only the clinical chemistry program was carried out with a frequency offour tests a year, the remaining six programs (in the field of hematology, acid-base balanceparameters and electrolytes ISE, coagulology) and three immunochemistry programs(including basic analytes, extended analytes, and cardiac markers) were conducted witha frequency of two tests a year. External quality assessment programs in the field ofspecialized immunochemistry and glycated hemoglobin HbA1c, by decision of the Ministerof Health, were withdrawn from implementation in 2022. Due to the earlier purchase ofcontrol materials for these programs by the organizer, the Central Center carried out onlyone test for each of them, without issuing annual certificates.</br><br><b>Material and methods:</b> As in the previous year, the Central Center purchased controlmaterials from renowned producers of in vitro diagnostic material devices for the programsbeing implemented. In order to ensure the quick and safe delivery of samples of controlmaterials to laboratories, in 2022 the organizer maintained the five-year-old transportprocedure using courier mail. The methods of assessing control results in the programshave not changed; the same method of calculating reference values, individual assessmentsof participants' control results and annual assessments has been maintained.</br><br><b>Results:</b> The results submitted by program participants in 2022 are presented in aggregateform in tables and figures. The initial tables I-IV contain organizational data of individualprograms, while the next tables V-VI present the collective results of all programs conductedin 2022. Further tables, i.e. VII-XIV, contain detailed data on the correctness of the assessedresults in individual programs and the percentage of correct results according to all criteriafor the assessed analytes.</br><br><b>Conclusions:</b> As compared to 2021, in all programs implemented in 2022, slight differenceswere obtained in the percentage of correct results according to the most favorable criterionfor the participant (from –0.64% to +1.44%); average +0.58%. Also, the annual regularityscores obtained in 2022 are comparable to the results of 2021. The differences range from–0.02 to +0.15 points.</br>

Статистичні тести для перевірки незалежності випадкових величин, що описують генерацію послідовностей в криптоалгоритмах

When a crypto-primitive, whose functions include the generation of a random/pseudo-random gamma, is admitted to operation, a necessary part of its quality checking is a sta-tistical testing of its output gamma and, often, intermediate gamma(s). Such requirement is applied, for example, to random/pseudo-random number generators (RNG/PRNG), stream ciphers, and block ciphers in different "stream" modes (such as OFB, CBC, etc). There exist widely used and well-known tools for checking the statistical properties of se-quences and generators, which are based on a set of statistical tests, like NIST STS set, Diehard, etc. At the same time, the other and very similar question, about independence of the se-quences (more precisely — independence of the corresponding random variables, that the considered sequences are their realizations) generated in such cryptoalgorithms, usually doesn’t attract enough attention. Nevertheless, it is also of great importance, because the dependence of the sequences can lead to predictability of the output gamma, which makes the cryptoprimitive vulnerable to statistical attacks. Therefore, there are no adequate and suitable tools for checking independence of different sequences, generated in the algo-rithms. In this work we deve¬loped and justified new set of three statistical tests for check-ing independence of random va¬riables, which realizations are internal or output sequences in encryption algorithms or RNG/PRNG. We also calculated reference values for limit sta-tistics for different parameters of sequences and different significance levels of tests. Re-sults of tests applications for independent and dependent random variables are given, which confirm correctness of proposed tests.

Exploring CPS-Extrapolated DLPNO-CCSD(T1) Reference Values for Benchmarking DFT Methods on Enzymatically Catalyzed Reactions.

Domain-based local pair natural orbital coupled-cluster singles doubles with perturbative triples [DLPNO-CCSD(T)] is regularly used to calculate reliable benchmark reference values at a computational cost significantly lower than that of canonical CCSD(T). Recent work has shown that even greater accuracy can be obtained at only a small additional cost through extrapolation to the complete PNO space (CPS) limit. Herein, we test two levels of CPS extrapolation, CPS(5,6), which approximates the accuracy of standard TightPNO, and CPS(6,7), which surpasses it, as benchmark values to test density functional approximations (DFAs) on a small set of organic and transition-metal-dependent enzyme active site models. Between the different reference levels of theory, there are changes in the magnitudes of the absolute deviations for all functionals, but these are small and there is minimal impact on the relative rankings of the tested DFAs. The differences are more significant for the metalloenzymes than the organic enzymes, so we repeat the tests on our entire ENZYMES22 set of organic enzyme active site models [Wappett, D. A.; Goerigk, L. J. Phys. Chem. A 2019, 123, 7057-7074] to confirm that using the CPS extrapolations for the reference values has negligible impact on the benchmarking outcomes. This means that we can particularly recommend CPS(5,6) as an alternative to standard TightPNO settings for calculating reference values, increasing the applicability of DLPNO-CCSD(T) in benchmarking reaction energies and barrier heights of larger models of organic enzymes. DLPNO-CCSD(T1)/CPS(6,7) energies for ENZYMES22 are finally presented as updated reference values for the set, reflecting the recent improvements in the method.

Assessment of aortic valve function in over 47,000 people using deep learning

Abstract Background Aortic valve (AV) stenosis (AS) is associated with a high global burden of mortality and morbidity. Previous studies suggest that even mild AS is associated with worse outcomes, prompting interest in AV function in a healthy population. The UK Biobank is a prospective cohort study with ∼500,000 participants of whom ∼10% have undergone cardiovascular MRI (cMRI). Purpose We aimed to develop a deep learning model to study AV function in cMRI at population level in the UK Biobank. Methods and Results We developed a U-Net based segmentation model with a ResNet34 encoder to study the velocity-encoded image series, computing peak velocity (cm/sec), mean peak gradient ("mean gradient"; mmHg), and aortic valve area (cm2) (AVA) in 47,223 participants. Next, we calculated reference values stratified by age and sex in participants without CVD. In healthy individuals (n=31,909), AVA was lower in older age groups, whereas peak velocity and mean gradient remained similar across age groups. Compared to women, men had greater AVA but similar peak velocity and mean gradient estimates. In the biomarker analysis (taken ∼9.5 years before cMRI), we observed an association of apolipoprotein B (ApoB) (0.033 SD increase per SD, P=3.1×10-12) and lipoprotein a (Lp (a)) (0.027 SD increase, P=4.8×10-07) with higher peak velocity. Using Mendelian Randomization, we found genetic evidence that Lp(a) causally contributes to higher peak velocity (β=0.04, P=6.4 × 10-10) and smaller AVA (β=-0.056, P=1.3 × 10-4). Similarly, ApoB causally contributes to higher peak velocity (β=0.072, P=1.3 × 10-6) and smaller AVA (β=-0.065, P=1.3 × 10-5) in Mendelian Randomization. Peak velocity was strongly associated with incident AV surgery (N=72, Hazard ratio [HR] 2.40 per SD, P=2.6×10-110) and AS (N=123, HR 2.10, P=7.7×10-138). The predictive power for AS was higher when using the top 10% vs the remaining 90% of distribution for mean gradient (N in top 10% with event=87, HR 24.91, P=2.4×10-43) and peak velocity (N=92, HR 33.01, P=3.0×10-43). After excluding individuals with at least mild aortic stenosis (peak velocity > 2m/sec, mean gradient >20mmHg, AVA >1.5 cm2) the top 10% of the remaining population was still highly predictive for AS using mean gradient (N=30, HR 8.90, P=9.4×10-15) and peak velocity (N=35, HR 13.15, P=1.6×10-18). Conclusion We found both epidemiological and causal genetic evidence that elevated ApoB and Lp(a) cause a reduction in AVA. Even aortic velocities below the threshold for mild AS were predictive of future clinical disease, suggesting that there may be a role for monitoring at AVA below the current threshold for mild AS. Future work is needed to understand whether clinical outcomes are better predicted by universal or sex-specific cutoffs.Figure 1:Workflow of deep learning modeHR of incident valvular disease

Research on ultimate Bearing Capacity of large Steel Box Girders under bending Moment

In order to study the ultimate bearing capacity of large welded box girder with initial imperfections, this paper considers the influence of material nonlinearity, geometric nonlinearity and initial imperfections, and uses the arc length increment method to modify Newton-Raphson formula to solve the problem. Through a large number of numerical simulation calculation, the calculation formula of stability ultimate bearing capacity of box girder under bending moment is summarized. The formula takes web height thickness ratio and flange width thickness ratio as parameters, which has a certain reference value for calculation and design of stability ultimate bearing capacity of welded box girder.

Characterizing fatigue damage behaviors of concrete beam specimens in varying amplitude load

In this paper, the random and nonlinear mechanical characteristics of the composition distribution of concrete in each phase are investigated to solve the difficulty of fatigue damage test of concrete beam specimens under variable amplitude loading. A three-dimensional (3D) concrete composite random aggregate meso-model of concrete beam specimens is built with Digimat as a composite modeling tool. Subsequently, the bending-tensile strength and fatigue life of the model under four-point bending loading is analyzed and calculated using Abaqus finite element analysis model based on the concrete elastic-plastic damage criterion. The mechanical behaviors of concrete materials under static load failure, multistage fatigue loading, and random fatigue loading are studied. Finally, compared with the test results, the following conclusions are obtained. The random aggregate model and elastoplastic damage mechanics model of concrete composite constructed by concrete in Abaqus and Digimat can better describe the geometric and distribution characteristics of composite structure and aggregate in concrete beams and the mechanical behavior of fatigue and static load failure. The difference is 4.08 % with the experimental results, which verifies the validity and reliability of the numerical simulation model, and the fatigue life of concrete beams under random loading Sra and Srb is 1622 and 164 times, respectively. The research results have certain guiding significance and reference value for accurate calculation of bending and tensile strength of concrete beams under specified raw material and mix ratio and prediction of fatigue damage cracking in airport cement concrete pavement structure.

The Impact of Social Well-Being on Population Diet Nutritional Value and Antiradical Status.

The paper presents the result of assessing the antiradical status of consumers (in the context of Russia) in connection with their well-being. This approach is based on a multistage study, in which the results of sociological surveys were applied, as well as estimates of the antiradical potential (ARP) of diets obtained using neural networks, bootstrapping the chemical composition of diets, and calculating reference values using mathematical models. The paper presents data collected from residents living in the territories of at least 21 regions and cities of Russia: Magadan, Saint Petersburg, Moscow, Krasnodar, Lipetsk, Vladivostok, Novosibirsk, Omsk, Voronezh, etc. A total of 1001 people were interviewed, which, according to our calculations, gives a margin of error in value of approximately 3.1%. To calculate the lack of vitamins in the diets of residents of the Russian Federation, data on the chemical composition of food products from the FNDDS database were used. The assessment of dietary habits showed a lack of vitamins below the recommended level in 73% of Russians for vitamin D, 59% for retinol, 38% for β-carotenes, 13% for vitamin E, and 6% for ascorbic acid. The study showed that at least 36% of the Russian population has a low antiradical status, while it was found that "poor" consumers are more likely to consume economically more expensive foods (in terms of their nutritional value). The "poor" segments of the population consume 180-305% more canned food and 38-68% more sweet carbonated drinks than other social groups, but their consumption of vegetables is 23-48% lower. On the contrary, "wealthy" consumers consume 17-25% more complex (varied) dishes, 10-68% more fresh vegetables, and 8-39% more fish. From the obtained values it follows that consumers with low levels of ARP in their diets are in a group with an increased probability of a number of "excess" diseases (diseases of the cardiovascular system, obesity, etc.). In general, the ARP values of food consumed for low-income segments of the population were 2.3 times lower (the ratio was calculated as the percentage of consumers below the level of 11,067 equivalents necessary for the disposal of free radicals generated in the human body per day) than for those who can afford expensive food (consumers with high income). A simple increase in consumption of unbalanced foods, in our opinion, will only contribute to the entry of these consumers into the "average diet trap". All this makes it imperative to develop comprehensive measures to create a new concept of public catering; otherwise, we can expect a reduction in both the health of the population and the performance of the economy of the whole country.

Research on Laplace transform of stress wave propagation relaxation function in multi-layer media

There are some difficulties in solving the theory of stress wave propagation in multi-layer media. To solve the problem of stress wave propagation in multi-layer media under the impact load, this paper theoretically makes further derivation and discussion based on viscoelastic analogy method. To further verify the feasibility of the theoretical solution, LS-DYNA is used to simulate the three-layer medium. The simulation results show that comparing the peak stress obtained from the numerical inversion of the Laplace function after the Laplace transform with the simulation results, the maximum error of the peak stress is about 9.5%, and the minimum error is about 1.7%. The results show that the theoretical solution agree with the simulation results, and the theoretical solution has specific feasibility. The theoretical solution method deduced in this paper further develops the viscoelastic analogy method, which has a specific reference value for the rapid calculation of the stress wave propagation law in multi-layer media.

Human interferon status. Standardization of the tests and establishing reference values

Background. Interferons are the most important component of nonspecific (congenital) resistance of the body, the history of their discovery dates back to 1957 and the study is still ongoing. Evaluation of an individual interferon status (IS) with the estimation of the sensitivity of leukocytes to immune reactive drugs has a practical aspect. IS is a set of parameters indicating the state of nonspecific resistance.Aim. To study the problems of standardizing the IS tests with the search for possible ways of standardizing the method and calculate reference values based on a large amount of data.Materials and methods. A retrospective statistical processing was performed using the database of the IS tests performed in the clinical diagnostic department of the laboratory center of Exacte Labs LLC from September 2020 to August 2022. Enzyme immunoassay kits based on commercial reagents were used. The paper describes the methodology for studying IS with an emphasis on the least standardized procedures.Results. Reference values were calculated using three indirect methods. The analysis of the results obtained made it possible to identify age groups for which it is advisable to establish reference values. The study results showed the inconsistency of the obtained reference values as compared with the previous ones, which indicates the need for their correction.Conclusion. The considered problems of performing and standardizing the method for IS analysis are of practical importance for establishing a standard methodology and an in vitro method. The reference values have been updated to avoid errors in the interpretation of the results and to increase the clinical significance of the study.

Design, Modeling, Control, and Experiments for Multiple AUVs Formation

The multiple autonomous underwater vehicle (AUV) formation plays an important role in underwater missions, such as oceanographic sampling and water pollution monitoring. This article presents the mechatronic design, modeling, formation control, and experiments of multiple AUVs. The structure of the AUV and a simplified mathematical model for tracking control are described. To achieve formation control, we formulate a control framework for the multiple AUVs. The upper layer is a formation algorithm based on a novel leader-follower control law. The bottom layer is a dynamic controller based on active disturbance rejection control (ADRC). The formation algorithm is in charge of calculating reference values for the followers to maintain a desired pattern with the leader. The stability and convergence properties of the algorithm have been analyzed using the Lyapunov stability method. Meanwhile, an ADRC approach-based dynamic controller is established to track the reference values. Numerical simulations are carried out to analyze formation control and validate the control framework. The multiple AUVs can switch and maintain the formation between the one-line pattern and the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V$ </tex-math></inline-formula> pattern. Finally, extensive formation field experiments involving the one-line pattern and the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V$ </tex-math></inline-formula> pattern show the good motion ability of the self-designed AUVs and also verify the feasibility of the proposed control approach. Note to Practitioners—The motivation of the article is to design a practical formation control approach for multiple AUVs and verify the control approach in the field. Although there have been a lot of prior research studies on multiple AUVs, how to design a formation control approach subjected to communication bandwidth constraints and how to develop multiple AUVs and verify the effectiveness of the control method in the field are worthy of intense investigation. Hence, this article builds the mechatronic design and dynamic model of the AUV and proposes a novel leader-follower formation control approach based on the dynamics and kinematic model of AUV. Besides, the stability of formation control for multiple AUVs is proven by the Lyapunov theorem. Multiple AUVs can switch and maintain formation between <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V$ </tex-math></inline-formula> pattern and one-line pattern with a smaller error. Finally, the performance of the proposed formation control strategy is experimentally verified using three self-made AUVs inside a large reservoir. The proposed method is suitable for multiple AUVs missions involving underwater surveillance, underwater pipeline inspection in the ocean.

Simplified calculation method and stability analysis of top beam cooperative pile–anchor supporting slope structure

Aiming at the problem of insufficient research on the action mechanism and stability calculation method of the top beam in the pile-anchor support structure, firstly the force and deformation model are established based on the elastic fulcrum method and the deformation coordination principle of the pile-anchor structure at the pile top and the anchor end in this paper. Secondly, the calculation model of the support structure under the synergy of the crown and beam and the simplified calculation method of the internal force, displacement and overall stability of the slope are constructed. Finally, combined with an engineering example, a MATLAB program was compiled for calculation, and the pile-anchor structures with crowned beams and without crowned beams were simulated and calculated by the finite element software PLAXIS 3D and Geo Studio. These three aspects are compared and verified. The results show that the internal force, deformation and minimum safety factor calculated by the method in this paper are basically consistent with the numerical simulation calculation results of the top beam condition; the existence of the top beam effectively enhances the bearing capacity of the pile body, and also restricts the displacement of the pile top development; the synergy of the crown and beam makes the safety factor of the slope increase significantly and improves the safety and stability of the slope. The research in this paper can provide a certain reference value for the theoretical calculation and design of the pile-anchor supported slope considering the top beam in engineering practice.

Biobank as a source of samples for determination of concentration reference ranges for cytokines, chemokines and growth factors circulating in the blood

Aim. To determine the reference ranges of concentrations of 38 cytokines, chemokines and growth factors, as well as to measure the content of these analytes in patients with neurodegenerative and cardiovascular diseases (CVDs) using biomaterial from the biobank repository.Material and methods. The study included 303 serum and plasma samples from 281 healthy donors, 242 samples from 224 patients with neurodegenerative diseases, and 164 samples from 152 patients with CVDs from the biobank of the of St. Petersburg City Hospital № 40. In all samples, the concentration of 38 cytokines, chemokines, and growth factors was determined by multiplex immunofluorescence assay.Results. Based on the measured concentrations in the group of healthy donors, non-parametric 95% reference ranges with 90% confidence intervals were calculated. For the majority of analytes, no sex and age differences were observed. In donors &gt;65 years of age, the concentration of macrophage inflammatory protein-1-α was reduced and the levels of interleukin-8 and the chemokine interferon-inducible protein 10 were increased. Young donors (18-35 years) had lower levels of tumor necrosis factor-α. In groups with neurodegenerative and cardiovascular diseases, multiple deviations from the calculated reference values were found.Conclusion. Certain reference intervals are intended to evaluate the concentrations of cytokines, chemokines and growth factors determined in blood serum or plasma using Human Cytokine/Chemokine Magnetic Bead Panel 1 reagents (Merck, Millipore) on the MAGPIX system and do not imply a direct transfer to other analytical methods.

Development of environmental benchmarks for the Belgian residential building stock

Over recent years Belgium has made meaningful effort in adopting Life Cycle Assessment (LCA) in building practice to improve building environmental performance. Today, architects can compare the environmental performance of different building designs with an online calculation tool that incorporates the national LCA method. However, they are still lacking environmental benchmarks to position themselves within current building practice. Furthermore, such benchmarks play an important role in the development of environmental targets in building regulation. In this research, benchmarks are defined for new residential buildings in Belgium. A bottom-up approach is followed consisting of a statistical analysis of reference buildings to define limit, reference and best practice values. The buildings are based on four representative typologies for Belgium, ranging from detached houses to apartments. Different variants are assessed including various energy performance levels and construction types (solid versus timber). The buildings’ life cycle impacts are calculated including the embodied (material) and operational (energy) impacts. Results are reported both for an aggregated environmental single-score and for Global Warming Potential (GWP). The calculated reference values for life cycle and embodied GWP (20 and 7 kgCO2eq/m2.year) are comparable to existing benchmarks in the literature. The results further highlight that building compactness provides the largest impact reduction, followed by construction type. Finally, limitations are discussed and recommendations are formulated for developing future benchmarks.

Numerical Investigation of Special Heat Transfer Phenomenon in Wire-Wrapped Fuel Rod of SFR.

Sodium-cooled reactors (SFR) have always been recognized as one of the most promising candidates for the fourth-generation nuclear systems as announced by the Generation-IV International Forum. In the design of SFR, helical wire-wrapped rod is applied to stabilize the structure of the rod bundle and enhance coolant mixing. Although there has been considerable research on SFR in computational fluid dynamics (CFD), the phenomenon of heat transfer has rarely been paid attention to. This article discovered that there exists reversed heat flux from coolant to wrapped wire, which is contrary to our usual understanding. This phenomenon has not been reported in previous CFD calculations. Hence, a solid heat conduction model is proposed to prove this phenomenon and analyze the heat transfer process. The simulation results show that the wrapping wire embedding depth, the shape of the calculation domain and the physical properties of all components have great influence on the magnitude of the reversed heat flux. The present findings will have strong influence on the temperature field and maximum value of the fuel rod as well as profound reference value for future flow calculation, especially in grid generation and treatment of the junction between the winding wire and fuel rod.

Reference values of low body mass index, mid-upper arm circumference, and calf circumference in cancer patients: A nationwide multicenter observational study

ObjectiveAnthropometric measurements including body mass index (BMI), mid-upper arm circumference (MUAC), and calf circumference (CC) are simple and convenient indicators of nutritional status and muscle mass. However, most of their reference values come from studies based on healthy Western populations. The optimal reference values of these anthropometric factors in Asian patients with cancer are unclear. The aim of this study was to develop reference values of severely and moderately low BMI, MUAC, and CC by analyzing a large sample of patients with cancer from a nationwide population. MethodsWe conducted a retrospective analysis of 16 104 patients who were diagnosed with malignant diseases from June 2012 to January 2019. The median age of the patients was 58 y, and 52.5% were men. Optimal stratification was used to calculate reference values using X-tile software. Kaplan–Meier and multivariate Cox analysis were performed to analyze survival data. A receiver operating characteristic analysis was conducted to test the performance of new reference values in diagnosing malnutrition. ResultsThe optimal reference values were calculated for BMI (moderately low: 19.7 [women] and 19 [men]; severely low: 16.7 [women] and 16.7 [men]), MUAC (moderately low: 24.5 [women] and 23.2 [men] severely low: 20.6 [women] and 19.4 [mnen]), and CC (moderately low: 29.1 [women] and 29.3 [men]; severely low: 26.7 [women] and 26.9 [men]). New reference values had more significant affects on mortality risk and better performance in predicting malnutrition than existing ones. ConclusionsThe present study defined reference values of moderately and severely low BMI, MUAC, and CC, which showed strong associations with quality of life, malnutrition, and mortality risk. New reference values from the present study are classification references specifically for the Asian population, which is a new step to promote the application of Global Leadership Initiative on Malnutrition criteria and its severity grading system in Asia.

Corneal Nerve Parameter Reference Values for Chinese Adults Assessed by Corneal Confocal Microscopy.

Background Confocal corneal microscopy is an excellent new noninvasive tool for assessing diabetic peripheral neuropathy. We aimed to investigate the clinical variables associated with corneal nerve parameters and establish reference values for clinical use in healthy Chinese adults. Methods The study enlisted 257 healthy volunteers (137 females and 120 males) from two clinical academic centers in China. Two experts captured and selected images of the central corneal subbasal nerve plexus at each center using the same corneal confocal microscopy instrument according to a commonly adopted protocol. Corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), and corneal nerve fiber length (CNFL) were measured using fully automated software (ACCMetrics). The correlation between clinical indicators and confocal corneal microscopy measures was determined using partial correlation. Quantile regression was used to calculate reference values and estimate the effects of clinical factors on the normative values of confocal corneal microscopy measures. Results Females had significantly higher CNFD, CNBD, and CNFL than males. There was no correlation between age, glycated hemoglobin (HbA1c), height, weight, body mass index (BMI), and any corneal nerve fiber parameter in both sexes. In either sex, age, weight, height, BMI, and HbA1c did not affect the 0.05th quantile values of any corneal nerve parameter. Conclusions This study establishes sex-adjusted reference values for corneal confocal microscopy measures in Chinese adults and provides a reference for clinical practice and research with this technique.

Validation of the Masimo O3™ regional oximetry device in pediatric patients undergoing cardiac surgery.

We assessed the accuracy of Masimo O3™ regional cerebral oxygen saturation (rSO2) readings by comparing them with reference values and evaluated the relationship between rSO2 and somatic tissue oxygen saturation (StO2) in children undergoing cardiac surgery. After anesthesia induction, pediatric sensors were applied to the forehead and foot sole, and rSO2 and StO2 values were monitored continuously. Before cardiopulmonary bypass (CPB), FIO2 was set to 0.2, 0.5, and 0.8 serially every 15min. After CPB, FIO2 was reversed. The reference values (SavO2) were calculated by combining arterial (SaO2) and central venous oxygen saturation (SvO2) readings from the arterial and central lines, respectively (0.7 [Formula: see text] SvO2 + 0.3 [Formula: see text] SaO2). In total, 265 pairs of rSO2/StO2 and SavO2 from 49 patients were analyzed. The bias, standard deviation (SD), standard error (SE), and root mean squared error (RMSE) of rSO2 were 2.6%, 4.5%, 0.3%, and 4.3%, respectively. The limits of agreement ranged from -6.3% to 11.6%. Trend accuracy analysis yielded a relative mean error of -1.4%, with an SD of 4.3%, SE of 0.2%, and RMSE of 3.9%. According to multiple linear regression analysis, the application of CPB, FIO2, Hb level, and tip location of the central venous catheter influenced the bias (all P < 0.05). Furthermore, the correlation between rSO2 and StO2 was weak (r = 0.254). rSO2 readings by the Masimo O3™ device and pediatric sensor had good absolute and trending accuracies with respect to the calculated reference values in children undergoing cardiac surgery. rSO2 and StO2 cannot be used interchangeably.Clinical trial registration http://clinicaltrials.gov (number: NCT04208906).

Issues pertaining to Mg, Zn and Cu in the 2020 Dietary Reference Intakes for Koreans.

In the current years, it has now become necessary to establish standards for micronutrient intake based on scientific evidence. This review discusses issues related to the development of the 2020 Dietary Reference Intakes for Koreans (KDRI) for magnesium (Mg), zinc (Zn), and copper (Cu), and future research directions. Following issues were encountered when establishing the KDRI for these minerals. First, characteristics of Korean subjects need to be applied to estimate nutrient requirements. When calculating the estimated average requirement (EAR), the KDRI used the results of balance studies for Mg absorption and factorial analysis for Zn, which is defined as the minimum amount to offset endogenous losses for Zn and Mg. For Cu, a combination of indicators, such as depletion/repletion studies, were applied, wherein all reference values were based on data obtained from other countries. Second, there was a limitation in that it was difficult to determine whether reference values of Mg, Zn, and Cu intakes in the 2020 KDRI were achievable. This might be due to the lack of representative previous studies on intakes of these nutrients, and an insufficient database for Mg, Zn, and Cu contents in foods. This lack of database for mineral content in food poses a problem when evaluating the appropriateness of intake. Third, data was insufficient to assess the adequacy of Mg, Zn, and Cu intakes from supplements when calculating reference values, considering the rise in both demand and intake of mineral supplements. Mg is more likely to be consumed as a multi-nutrient supplement in combination with other minerals than as a single supplement. Moreover, Zn-Cu interactions in the body need to be considered when determining the reference intake values of Zn and Cu. It is recommended to discuss these issues present in the 2020 KDRI development for Mg, Zn, and Cu intakes in a systematic way, and to find relevant solutions.

Baseline Aerobic Fitness in High School and College Football Players: Critical for Prescribing Safe Exercise Regimens

Nontraumatic fatalities occur on a regular basis in high school (HS) and college football athletes, primarily in obese linemen performing high-intensity exercise. One contributing factor to these deaths may be a mismatch between baseline aerobic (cardiorespiratory) fitness and exercise regimens. There is a wide range of aerobic fitness in HS and college football players. Body mass index (BMI) is a safe and simple method for estimating baseline aerobic fitness. Retrospective cohort study. Level 3. A retrospective review was performed on 79 HS football athletes who had VO2Peak (mL·kg-1·min-1) measured during the offseason. Multivariate regression analysis was used to determine if BMI (obese, overweight, and normal; kg/m2), position played (linemen vs other), year in school (freshmen vs other), and/or race (African American vs White) were risk factors for poor aerobic fitness. A separate cohort of 135 (48 HS; 87 college) football athletes performed a 6-minute run test to determine speed (miles/min), extrapolate VO2Max, and calculate reference values for suggested upper threshold safe starting speeds (85% of maximum) for aerobic training based on BMI. The relationship between BMI and VO2Peak was assessed. The exercise regimens (speeds) of 2 collegiate football fatalities from the public domain were used to predict their VO2Max values. Mean VO2Peak (mL·kg-1·min-1) was 38.5 ± 8.6 (range 19.1-60.6); when grouped by BMI, low scores (<40) were found in 87.5% of obese (32.4 ± 7.7), 47.8% of overweight (40.8 ± 7.6), and 45.2% of normal (41.4 ± 7.8) athletes. VO2Peak was significantly lower in linemen (32.8 ± 6.4; P = 0.007) compared with nonlineman (41.8 ± 7.9), and in obese players (by BMI; 32.4; P = 0.019) compared with nonobese players (41.4 ± 7.6), but did not differ by age, year in school, or race. Means for speed (min/mile) and extrapolated VO2Max (mL·kg-1·min-1) for the 6-minute run test by BMI groups were both significantly different (P = 0.001) for normal (7.0 ± 0.6; 51.1 ± 2.6), overweight (7.6 ± 0.8; 46.5 ± 3.2), and obese (8.9 ± 1.5; 36.8 ± 5.9) athletes. There was a significant negative correlation (r = -0.551; P = 0.001; R2 = 0.304) between VO2Peak and BMI. Safe starting speed recommendations for running 1 mile range from 7.3 to 12.1 min/mile for BMIs 20 to 40 kg/m2 for HS and college athletes. For the 2 fatalities (mean, BMI of 36.5 kg/m2) repetitive sprint speeds were 49 and 89% higher than our safe starting speeds for their BMI. A large spectrum of baseline aerobic fitness was noted in HS and college football players. Obese players and linemen had statistically lower baseline aerobic fitness, a major risk factor for possible heat illness. BMI is an acceptable surrogate for VO2Peak and can be employed to develop safe training regimens without the need for a maximum fitness test, which can place the athlete at risk for a medical event. Knowledge of BMI provides an estimate of baseline aerobic fitness and a foundation for prescribing safe, individualized exercise regimens.

Reference values for free 25-hydroxy-vitamin D based on established total 25-hydroxy-vitamin D reference values

Measurements of total 25-hydroxyvitamin D (t25(OH)D) are currently primarily used to assess the vitamin D status. The lipophilic cell membrane can only be passed by the un-bound form of 25-hydroxyvitamin D: free 25-hydroxyvitamin D (f25(OH)D). It is thought that f25(OH)D does reflect its biological actions better than t25(OH)D. However, as of today, there are no established guidelines for the clinical use of f25(OH)D.We analysed 5060 patients with simultaneous measurements of free and total 25(OH). Linear regression was used to study the relationship between free 25(OH)D and total 25(OH)D. We reviewed and used the established t25(OH)D reference values and determined the slope of the relationship between them to calculate reference values for f25(OH)D.F25(OH)D and t25(OH)D showed a strong positive linear (r = 0.8395, p < 0.0001) correlation. The slope of the relationship was 0.2833 ± 0.00257. The recommended threshold level of f25(OH)D is 8.499 pg/mL, corresponding to a target concentration for t25(OH)D of at least 30 ng/mL considered as sufficient in most of the international vitamin D guidelines. The upper limit for vitamin D is less clear in the guidelines. Most experts favour an upper limit for t25(OH)D of 100 ng/mL. This is equivalent to 28.330 pg/mL f25OHD.We established based on international guidelines for t25(OH)D reference values for f25(OH)D that are urgently needed for clinical use of f25(OH)D. However, clinical studies with f25(OH)D to confirm our suggestions are needed but will take time.