Standard Samples Research Articles

Higher initial levothyroxine doses and very early treatment start may lead to better cognitive outcomes in children with congenital hypothyroidism.

This study aimed to assess the cognitive development of individuals with congenital hypothyroidism. Using hospital records, we identified 180 patients with congenital hypothyroidism born between 1980 and 2018 in Turku and Kuopio University Hospital catchment areas. Cognitive development was evaluated in 22 adults (7 males and 15 females) and 20 children (8 males and 12 females) using age-specific Wechsler Intelligence Scales. Full-scale IQ (FSIQ) and the four indices were compared to standardisation samples. Simple linear regression was used to test whether treatment-related variables predicted FSIQ. FSIQ and its four indices differed significantly from the standardisation sample in adults with congenital hypothyroidism (FSIQ 87.64, SD 13.70, p < 0.001) but not in children (FSIQ 97.90, SD 15.12). Adults had received a lower initial levothyroxine dose than children (8.1 mg/kg, 95% CI 7.2-9.0 vs. 10.2 mg/kg 9.7-10.7, p < 0.001), and their treatment was initiated later (4.8 days, 95% CI 4.0-5.6 vs. 3.6 days, 2.9-4.2, p = 0.018). Adults with congenital hypothyroidism had a significantly lower FSIQ compared to the population standard, while children's FSIQ did not differ. Our findings suggest that a higher initial levothyroxine dose together with very early treatment start may lead to better cognitive outcomes.

A multimodal intervention to revitalize a gynecologic oncology tissue bank increases patient enrollment and expands standardized sample collection

A multimodal intervention to revitalize a gynecologic oncology tissue bank increases patient enrollment and expands standardized sample collection

A multi-modal intervention to revitalize a gynecologic oncology tissue bank increases patient enrollment and expands standardized sample collection

A multi-modal intervention to revitalize a gynecologic oncology tissue bank increases patient enrollment and expands standardized sample collection

Intraoperative short-term blood pressure variability and postoperative acute kidney injury: a single-center retrospective cohort study using sample entropy analysis

BackgroundTo investigate if intraoperative very short-term variability in blood pressure measured by sample entropy improves discrimination of postoperative acute kidney injury after noncardiac surgery.MethodsAdult surgical patients undergoing general, thoracic, urological, or gynecological surgery between August 2016 to June 2017 at Seoul National University Hospital were included. The primary outcome was acute kidney injury stage 1, defined by the Kidney Disease: Improving Global Outcomes guidelines. Exploratory and explanatory variables included sample entropy of the mean arterial pressure and standard demographic, surgical, anesthesia and hypotension over time indices known to be associated with acute kidney injury respectively. Random forest classification and L1 logistic regression were used to assess four models for discriminating acute kidney injury: (1) Standard risk factors which included demographic, anesthetic, and surgical variables (2) Standard risk factors and cumulative hypotension over time (3) Standard risk factors and sample entropy (4) Standard risk factors, cumulative hypotension over time and sample entropy.ResultsTwo hundred and thirteen (7.4%) cases developed postoperative acute kidney injury. The median and interquartile range for sample entropy of mean arterial pressure was 0.34 and [0.26, 0.42] respectively. C-statistics were identical between the random forest and L1 logistic regression models. Results demonstrated no improvement in discrimination of postoperative acute kidney injury with the addition of the sample entropy of mean arterial pressure: Standard risk factors: 0.81 [0.76, 0.85], Standard risk factors and hypotension over time indices: 0.80 [0.75, 0.85], Standard risk factors and sample entropy of mean arterial pressure: 0.81 [0.76, 0.85] and Standard risk factors, sample entropy of mean arterial pressure and hypotension over time indices: 0.81 [0.76, 0.86].ConclusionAssessment of very short-term blood pressure variability does not improve the discrimination of postoperative acute kidney injury in patients undergoing non-cardiac surgery in this sample.

Intellectual Differences Between Boys and Girls, 35 Years of Evolution in France from WISC-R to WISC-V

The French adaptation of the Wechsler Intelligence Scale of Children, 5th edition (WISC-V) was an opportunity to examine if some common representations of gender differences in intellectual abilities are supported by empirical evidence. The WISC-V standardization sample provided data on a wide range of cognitive tests in a large sample of 6- to 16-year-old children representative of the French population. This sample included 517 boys and 532 girls. The WISC-V data were compared to those of the French standardization samples of three previous versions of the WISC (WISC-R, WISC-III, and WISC-IV). These four standardization samples span a 35-year period. The data analysis of the WISC-V standardization sample and the three previous versions of this intelligence scale showed that the performance gaps on intellectual tests between girls and boys have gradually narrowed over time. Almost no gender differences were observed in the WISC-V standardization sample, not only in IQ but also in key facets of intelligence. Data do not support the stereotype that girls are better at verbal tasks and boys are better at visuospatial tasks. However, some statistically significant differences remain, but the magnitude was generally small with no practical implications. The only important difference is in favor of girls and concerns performance on processing speed tasks that require visual discrimination, attentional control, and writing.

ВИТАМИН D3: ПОДРОБНАЯ ХАРАКТЕРИСТИКА СУБСТАНЦИИ И АНАЛИЗ

The article examines in detail the issues of standardization of the obtained vitamin D substance using its own original technological scheme, and the possibility of further use of the substance to create a standard sample (SS). The work traces the current problem associated with the lack of production of domestic vitamin D substance. The object of study is the vitamin D substance isolated from natural raw materials. To assess the quality of the obtained substance, quantitative and qualitative determination methods, high-performance liquid chromatography (HPLC) at a wavelength of 265 nm, IR spectroscopy in the emission range of the spectrum from 4000 cm-1 to 400 cm-1, organoleptic method, polarimetry, refractometry and other methods of analysis were used. The obtained vitamin D substance, according to its quality characteristics, can be confidently used not only as a material for the manufacture of SS, but also as a starting substance in the pharmaceutical, food and agricultural sectors of the national economy.

Suitability techniques for transforming marginal lands to support building infrastructures in parts of Rivers State, Nigeria

This study examined sustainability techniques for transforming marginal lands to support building infrastructures in parts of Rivers State, Nigeria. The study adopted the cross-sectional survey research design method employing the use of standard penetration approach utilizing Geographic Information System analysis. Marginal lands were delineated as margins of watrbodies using the polygon method in ArcGIS, and were created as a feature class for polygon data (shape file). The locations, river margins and roads formed point data, polygon data and line data respectively. Digitisation was achieved using Orthophoto Image in ArcGIS 10.0 software where seven geotechnical boreholes were located and drilled using permission rig to a depth of 10.5m in five local government areas of Rivers State. In-situ standard penetration testing and soil sampling for laboratory geotechnical properties was done using standard laboratory techniques. Findings of the analysis show that silty and sandy clay are the dominant soil within the foundation depth of 1-2.5m which are underlained by clays and sands of varying densities and grain sizes with their specific gravity value of ranges of 1.9 – 2.66 depicting that the areas are underlined by organic, diatomaceous and high porosity permeability soils deposits under water logged conditions. The cohesive strength of the soils vary from 65KN/m 2 - 115KN/m 2, angle of internal friction ranged from 0o – 10o and shear strength ranged from 110KN/m 2 – 147.46KN/m 2 and the allowable bearing capacities of 180.22KN/m 2 – 236.05KN/m 2. The stability techniques for the transformation of the land to support building infrastructures are pre-construction soil stabilization and marginal land reinforcement. The study thus recommends for building summation of consolidated techniques for sustainability of infrastructures.

Optimizing Sample Size Determinations for Phase 3 Clinical Trials in Type 2 Diabetes.

An informed estimate of subject-level variance is a key determinate for accurate estimation of the required sample size for clinical trials. Evaluating completed adult Type 2 diabetes studies submitted to the FDA for accuracy of the variance estimate at the planning stage provides insights to inform the sample size requirements for future studies. From the U.S. Food and Drug Administration (FDA) database of new drug applications containing 14,106 subjects from 26 phase 3 randomized studies submitted to the FDA in support of drug approvals in adult type 2 diabetes studies reviewed between 2013 and 2017, we obtained estimates of subject-level variance for the primary endpoint-change in glycated hemoglobin (HbA1c) from baseline to 6 months. In addition, we used nine additional studies to examine the impact of clinically meaningful covariates on residual standard deviation and sample size re-estimation. Our analyses show that reduced sample sizes can be used without interfering with the validity of efficacy results for adult type 2 diabetes drug trials. This finding has implications for future research involving the adult type 2 diabetes population, including the potential to reduce recruitment period length and improve the timeliness of results. Furthermore, our findings could be utilized in the design of future endocrinology clinical trials.

Transferability of Model-Based Static Coefficient of Friction

The accurate determination of static coefficients of friction (COFs) is crucial in engineering design, yet standard reference values often show considerable variability. As a result, engineers frequently need to perform experimental COF measurements to ensure the reliable transferability of model-based COFs to real-world components. However, the effectiveness of cost-efficient laboratory tests, typically conducted on standardized samples, in reflecting actual component performance is often questioned as it is not trivial to transfer and scale the tribosystem. This study addresses this issue by conducting friction coefficient experiments on interference fits and flange connections, comparing the results with laboratory-based COF tests. The findings reveal a strong correlation when the tribological conditions of the real assembly are replicated in the lab. This research offers a method to enhance the accuracy and transferability of COF values from lab tests to practical applications, providing engineers with a more reliable approach to friction testing.

Combined Analysis of Grade Differences in Lapsang Souchong Black Tea Using Sensory Evaluation, Electronic Nose, and HS-SPME-GC-MS, Based on Chinese National Standards

Tea standard samples are the benchmark for tea product quality control. Understanding the inherent differences in Chinese national standards for Lapsang Souchong black tea of different grades is crucial for the scientific development of tea standardization work. In this study, Lapsang Souchong black tea of different grades that meet Chinese national standards was selected as the research object. The aroma characteristics were comprehensively analyzed through sensory evaluation, electronic nose, and HS-SPME-GC-MS (headspace solid-phase microextraction gas chromatography–mass spectrometry). The findings indicate that the higher-grade Lapsang Souchong has a higher evaluation score. The results of electronic nose analysis indicate that the volatiles with differences in tea of different grades were mainly terpenoids and nitrogen oxides. The results of HS-SPME-GC-MS analysis show that the odor characteristics of the super-grade samples are mainly floral and fruity, and these substances mainly include D-Limonene, 3,7-dimethyl-1,6-octadien-3-ol and 3-Hydroxymandelic acid, and ethyl ester. The primary aroma characteristics of the first-grade samples are floral, sweet, woody, and green, with key contributing compounds including 2-Furanmethanol, 1-Octen-3-ol, and 5-ethenyltetrahydro-α,α,5-trimethyl-cis-, 4,5-di-epi-aristolochene. The main aroma characteristics of the second-grade samples are green, herbal scent, and fruity, and the main substances include 3,7-dimethyl-1,6-octadien-3-ol, 2,3-dimethylthiophene, Dihydroactinidiolide, and Naphthalene-1-methyl-7-(1-methylethyl)-. It is worth noting that the second-grade samples contain a large amount of phenolic substances, which are related to the smoking process during processing. This study lays a solid foundation for the preparation of tea standard samples and the construction of the tea standard system.

Experimental Study of the Mechanical Properties of Mortar with Biobío Region Clam Shells Used as a Partial Replacement for Cement

The use of seashells as a partial substitute for cement in construction not only offers an innovative solution for marine waste management but also contributes to reducing the carbon footprint of the cement industry, decreasing the CO2 emissions associated with cement production and promoting more sustainable construction practices. This study addresses the mechanical behavior of mortar specimens with partial cement replacement using crushed Biobío region clam shells, both calcined and uncalcined, at substitution rates of 5% and 10%. This approach allows the analysis of their effect on the mechanical strength and properties of the mortar, which has not been widely investigated in the Chilean context or with this particular species of shell. For the mechanical characterization of the specimens, tensile flexural tests and compressive tests were were conducted at ages of 3, 7, 14, and 28 days. The compressive strengths of the samples that incorporated calcined residue with partial cement replacements of 5% and 10% were 83.69% and 78.27%, respectively, of the average strength of 20.97 MPa reached by the standard sample. In terms of their tensile flexural strength, these samples reached average strengths of 104.31% and 104.04% of the strength of 12.12 MPa obtained by the standard sample. In the case of the uncalcined samples, the 5% and 10% replacements reached 103.55% and 102.64% of the tensile strength of 15.54 MPa obtained by the standard sample, while they reached 92.32% and 80.07% of the compressive strength of 27.81 MPa achieved by the standard sample. From these results, it is determined that the calcined shells did not improve the mechanical resistance of the mortar, suggesting that the calcination process must be studied in depth.

Evidence for Distinct Active Sites on Oxide-Derived Cu for Electrochemical Nitrate Reduction.

Cu is a promising catalyst for electrochemical nitrate (NO3-) reduction. However, desorption of the nitrite (NO2-) intermediate can occur, leading to lowered ammonia productivity and Faradaic efficiency. Here, we discovered that this does not occur with oxide-derived Cu due to the presence of at least two distinct types of cooperative active sites: one for NO3- → NO2- and another for NO2- → NH3. As a result, oxide-derived Cu exhibits enhanced ammonia productivity with a mixed NO3-/NO2- feed relative to pure NO3- or NO2-. In contrast, this was not observed with a standard Cu sample, implying the presence of only a single type of active site. Our dual-site hypothesis was supported by attenuated total reflection surface enhanced infrared absorption spectroscopy and isotopic labeling experiments involving co-reduction of 15NO3-/14NO2-. We also successfully simulated our experimental results using a mathematical model involving two different adsorption sites. These findings motivate the need for further study and rational design of such active sites.

Hydrochemical Assessment of Groundwater in Ludhiana and Amritsar Districts of Punjab and Identification of Fluoride Hotspots using GIS

High fluoride concentrations in soil, water, or air can pose serious environmental and health risks to plants, and animals. Along with other hydrochemical parameters, this study investigates fluoride concentrations in the groundwater in the Ludhiana and Amritsar districts of Punjab, India. A total of 222 water samples were uniformly collected at approximately five-kilometer intervals for hydrochemical analyses. Statistical methods such as inverse distance weighting (IDW) and correlation matrices were used to assess the fluoride distribution and its relationships with other parameters. According to WHO guidelines, most fluoride concentrations were below 0.6 ppm in Ludhiana (84.30%) and Amritsar (77.23%). Fluoride levels that were within the permissible range (0.6–1.5 ppm) were found in 15.70% of Ludhiana’s samples and 21.78% of Amritsar’s samples; only 1% of Amritsar’s samples exceeded the permissible limit (&gt;1.5 ppm). The water quality index (WQI) analysis indicated that0.83% of the groundwater samples from the Ludhiana district and 4.95% from the Amritsar district were unfit for consumption. This study demonstrates the importance of standardized sample collection and the use of GIS technology for comprehensive hydrochemical assessments, raising awareness and reducing health risks.

Accelerator mass spectrometer facility for heritage radiocarbon dating at NRICH, Korea

Abstract In 2021, the National Research Institute of Cultural Heritage (NRICH) installed a new accelerator mass spectrometer (AMS) to date Korean national heritage. Before conducting radiocarbon dating, the facility was set up and its performance was assessed. AMS system parameters have been optimized. Measurement of standard and blank samples was verified. Intercomparison analyses were also performed using heritage samples. The F14C value of NIST 4990C was 1.3406 and the background level was 0.0024. Both IAEA-C7 and C8 were confirmed to match the reference value within the 1-σ range. The NIST 4990C measurement results confirmed high precision and accuracy, with 1-σ values below 2‰. In the intercomparison, the error for each sample was 2‰. Thus, based on this study, NRICH plans to launch a dating service specializing in cultural heritage.

ImageJ and smartphone app chemistry analyzer using image-based colorimetric assay for quantitative detection of melamine

Abstract A smartphone-assisted microchemistry analyzer with an image-based colorimetric assay using ImageJ and a smartphone app detection method was successfully developed for the quantitative detection of melamine (MEL). The color changes of the MEL in the colloidal gold lateral flow immunoassay strip were captured and analyzed using a smartphone-controlled analyzer with an LED light source and a smartphone camera. The smartphone camera and light source were used to read the colorimetric signal from the strip, and a smartphone app was written and installed onto the smartphone. The quantitative analysis was validated with ImageJ and smartphone app colorimetric analysis. The limits of detection (LODs) for ImageJ and the smartphone app were calculated as 0.30 and 0.07 mg/L, respectively. The highly quantitative relationships between the MEL concentrations and the optical density and gray value of the ImageJ and smartphone app detection method. The designed image-based biosensor is successfully applied to detect MEL in solution of standard MEL and commercial milk samples.

Technical strategy for reapplying coatings on solar tower receiver tubes using concentrated flux

Reapplying the coating is crucial to restore optimal receiver performance. However, the heat treatment must be conducted onsite since the receiver cannot be removed from the tower. This study explored effective strategies for maximizing the coating’s performance after reapplication. The impact of different aimpoint strategies on the receiver’s surface temperature was analyzed using the heliostat field and the three-dimensional receiver model. Experimental tests were conducted using a solar lamp to study temperature variation curves of coatings on different tube panels under various aiming strategies, and absorptance was then measured. The optimal recoating strategy was determined through a comprehensive analysis of the system’s power generation and its Levelized Cost of Energy across its entire lifecycle. The “image size priority” strategy led to significant temperature variations among tube panels and within each panel. In contrast, the “segmented target flux” strategy effectively minimizes temperature differences, ensuring that over 91.25 % of the receiver tube panel reached temperatures above 550 °C. Comparatively, under the “image size priority” and “segmented target flux” strategies, the coating’s absorptance at the molten salt inlet panel is lower by 1.84 % and 0.10 %, respectively, compared to the standard sample. The effectiveness of the “segmented target flux” strategy becomes more pronounced with shorter recoating intervals. The research contributes to enhancing the maintenance performance of the coating and the operational efficiency of the receiver.

Single-stage NBI sampler for PM1 mass and five-stage NBI-NMCI sampler for PM1 mass distribution measurements

In recent years, concerns about the health and environmental risks associated with PM1 particles have increased. However, existing PM1 sampling instruments remain to be improved mainly because their PM1 inlets have particle loading and bounce issues. To address these challenges, PM1 inlets based on the Non-Bouncing Impactor (NBI) technique were developed. These inlets employ vacuum oil-wetted glass fiber filter (GFF) substrates to eliminate particle bounce and incorporate a daily vacuum oil injection to prevent particle loading. The 16.7 L/min PM1 NBI, modified from the PM2.5 M-WINS design with a reduced diameter of the single nozzle, was designed to adapt readily with current standard sampling and monitoring systems. The cut-size (Dpa50) of 0.99 ± 0.02 μm was determined by considering the effects of Reynold number and the ratio of jet-to-plate distance and nozzle diameter. Field tests comparing the 16.7 L/min PM1 NBI sampler to the 9-stage NCTU Micro-orifice Cascade Impactor (NMCI9) revealed small sampling biases, with a mean difference of +0.26 ± 2.28 μg/m3 for PM1 measurements when silicone oil-coated aluminum foil (AF) and GFF-AF were used in the NMCI9. The NBI with the oil-wetted GFF substrate effectively removed particles larger than 1.0 μm, resulting in more accurate PM1 mass concentration measurements. Additionally, the development of a 5-stage NMCI with the 30 L/min PM1 NBI as the first stage enabled detailed measurement of PM1 mass distribution in two modes, which was challenging when measuring the entire mass distribution of ambient aerosols. The distribution of size-dependent water-soluble inorganic ions in PM1 showed dominance of SO42− and NH4+ in PM1 compared to PM2.5. In summary, the PM1 NBI enhances accuracy for long-term atmospheric sampling by addressing particle loading and bounce, making it a more reliable standard sampling instrument.

Corneal and intraocular pressure changes associated to the circadian rhythms: a narrative review.

To synthesize the current body of research regarding the diurnal variations in intraocular pressure (IOP) and corneal biomechanical and morphological parameters, highlighting their significance in various eye conditions. A comprehensive review of studies on the diurnal variations of IOP and corneal parameters was conducted. Tonometry findings from various studies were assessed, including the Goldmann applanation tonometry (GAT) and non-contact tonometers. Data on the variations in central corneal thickness (CCT), corneal curvature, and corneal biomechanics measured by the Ocular Response Analyzer system across different population groups was extracted and analyzed. In both healthy subjects and those with Fuchs dystrophy, IOP and CCT demonstrate marked diurnal declines. GAT remains the gold standard for tonometry, with the highest reliability. However, its measurements are influenced by CCT. Keratoconus patients and those with pseudoexfoliation showed significant diurnal variations in IOP. The biomechanical parameters, especially corneal hysteresis (CH) and the corneal resistance factor (CRF), largely remain stable throughout the day for most of eye conditions, with some exceptions. Notably, the corneal morphology diurnal variation, particularly curvature, yielded mixed conclusions across studies. Circadian rhythms significantly influence various corneal parameters, most notably IOP and CCT. Further studies should emphasize standardized approaches larger sample sizes, and delve deeper into less-explored areas, such as the effects of orthokeratology lenses on diurnal biomechanical shifts.

A Kernel-Based Calibration Algorithm for Chromatic Confocal Line Sensors.

In chromatic confocal line sensors, calibration is usually divided into peak extraction and wavelength calibration. In previous research, the focus was mainly on peak extraction. In this paper, a kernel-based algorithm is proposed to deal with wavelength calibration, which corresponds to the mapping relationship between peaks (i.e., the wavelengths) in image space and profiles in physical space. The primary component of the mapping function is depicted using polynomial basis functions, which are distinguished along various dispersion axes. Considering the unknown distortions resulting from field curvature, sensor fabrication and assembly, and even the inherent complexity of dispersion, a typical kernel trick-based nonparametric function element is introduced here, predicated on the notion that similar processes conducted on the same sensor yield comparable distortions.To ascertain the performance with and without the kernel trick, we carried out wavelength calibration and groove fitting on a standard groove sample processed via glass grinding and with a reference depth of 66.14 μm. The experimental results show that depths calculated by the kernel-based calibration algorithm have higher accuracy and lower uncertainty than those ascertained using the conventional polynomial algorithm. As such, this indicates that the proposed algorithm provides effective improvements.

Determination of the Redox Ratio of Iron in a Diamagnetic Matrix Using Low-Field NMR Relaxometry.

Proton nuclear magnetic resonance (NMR) relaxometry is proposed to determine the iron redox ratio of slag samples. It depends on the paramagnetic effect on bulk water relaxation times. Experiments have been carried out to calibrate the relationship between the concentration of Fe3+ and Fe2+ ions and the measured relaxation times on prepared standard samples. It is shown that Fe2+ ions have very different effects on the relaxation times than Fe3+ ions. For the solid slag samples, digestion in an acid was used to produce solutions with a pH of 1.0. Hydrogen peroxide (H2O2) was then added to the digested samples to oxidize Fe2+ ions to Fe3+ ions. The concentration of Fe2+ and Fe3+ ions in solution can be calculated by measuring the relaxation times before and after oxidation. The Fe3+/∑Fe ratio of slag samples was also investigated by wet chemistry and 57Fe Mössbauer spectroscopy and calculated by FactSage at the equilibrium state. The results obtained from different methods are consistent, indicating that this NMR relaxometry method is reliable.