First Set Of Measurements Research Articles

Examining Environmental Influences on Pain Perception Using Virtual Reality

Virtual reality (VR) and biophilic design are two emerging areas of research in interior design and medical settings. VR is a rapidly developing technology which has revolutionized the field of interior design. This technology allows designers to create immersive environments that simulate the scale and depth of spaces in reality. Biophilic design focuses on incorporating natural elements into interior spaces to promote a human centered approach to design. Studies have found an association between the use of biophilic design and improvement in patient outcomes within the medical setting. However, little research has been conducted on how changes in the virtual environment may impact pain perception. This study aims to explore the impact of VR and biophilic design on human pain perception. Pain perception was measured via pain-pressure threshold (PPT) using a pressure algometer in kilogram-force (kgf) and Numeric Pain Rating Scales (NPRS). The study involved a series of measurements comparing participants' pain perceptions through PPTs and NPRS scores. Measurements were taken on five separate occasions. The first set of measurements were recorded outside of VR to establish baselines, and the remaining four measurements were taken within VR. Participants viewed a series of VR rooms modeled after a hospital setting with each room exhibiting increasing levels of environmental stimulation. This study examined the relationship between environmental stimuli and pain perception. The level of environmental stimuli that each participant was exposed to was increased by presenting a higher degree of biophilic elements. Biophilic elements incorporate plants, colors, natural materials, and the manipulation of architectural surfaces to provide a naturally calming effect to spaces. Results from this study support the idea that increasing the level of environmental stimuli in a virtual environment decreases the pain perception of those viewing the environment.

Experimental characterization of stall noise on a pitching airfoil in an anechoic wind tunnel

Dynamic stall noise is one of the potential source of amplitude modulations associated with wind turbine noise. This phenomenon is related to the periodic separation and reattachment of the boundary layer on the wind turbine blade suction side during its rotation. Within the framework of the PIBE project (Predicting the Impact of Wind Turbine Noise), experiments were conducted in an anechoic wind tunnel in order to characterize stall noise on a pitching airfoil in both static and dynamic conditions. A first set of measurements was performed using an airfoil equiped with pressure taps to measure both steady and unsteady wall pressure as well as far-field acoustic pressure. These measurements were used to identify the noise regimes associated with different angles of attack, and to relate them with the boundary layer evolution. In a second experiment, synchronized flow and acoustic measurements have been obtained to identify the coherent aerodynamic structures responsible for the noise radiation. The velocity fluctuations evaluated from the time-resolved particle image velocimetry (TR-PIV) data are correlated with acoustic pressure to localize aeroacoustic sources, and various tools such as vortex detection methods and spectral proper orthogonal decomposition are applied to identify the nature of these sources.

CLSI-based verification and de novo establishment of reference intervals for common biochemical assays in Croatian newborns.

This study aimed to examine whether the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) reference intervals for 19 commonly used biochemical assays (potassium, sodium, chloride, calcium, magnesium, inorganic phosphorous, glucose, urea, creatinine, direct and total bilirubin, C-reactive protein (CRP), total protein, albumin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP) and lactate dehydrogenase (LD)) could be applied to the newborn population of one Croatian clinical hospital. Reference interval verification was performed according to the CLSI EP28-A3c guidelines. Samples of healthy newborns were selected using the direct a posteriori sampling method and analyzed on the Beckman Coulter AU680 biochemical analyzer. If verification wasn't satisfactory, further procedure included de novo determination of own reference intervals by analyzing 120 samples of healthy newborns. After the first set of measurements, 14/19 tested reference intervals were adopted for use: calcium, inorganic phosphorous, glucose, urea, creatinine, total bilirubin, CRP, total protein, albumin, AST, ALT, GGT, ALP and LD. A second set of samples was tested for 5 analytes: potassium, sodium, chloride, magnesium and direct bilirubin. The verification results of the additional samples for sodium and chloride were satisfactory, while the results for potassium, magnesium and direct bilirubin remained unsatisfactory and new reference intervals were determined. The CALIPER reference intervals can be implemented into routine laboratory and clinical practice for the tested newborn population for most of the analyzed assays, while own reference intervals for potassium, magnesium and direct bilirubin have been determined.

EXPERIMENTAL RESEARCH ON A KINETIC HYDRO TURBINE - GENERATOR ASSEMBLY

The present paper is part of a larger project whose purpose is to develop a new hydrokinetic turbine-generator assembly, suitable for very low head water courses. It presents the experimental results of a turbine–generator physical model, installed on the tailrace of Mihailesti Hydropower Plant. In order to carry out the measurements, a floating structure and an anchoring system was installed on the power plant tailrace. This system also allowed the translation of the assembly between the two shores. A first set of measurements followed the water velocity and depth in the channel at various load values of the hydropower plant units, in order to determine the proper conditions for testing the model. The turbine gives the possibility of blades adjustment at three different angles, 0, 9 and 14 degrees respectively. Therefore, a set of measurements has been performed for each position of the blades. The measured parameters were the electric parameters of the generator such as voltage, current and the power variation with rotation speed. For the blades adjustment of 9 degrees and 1.76 m/s water velocity, the generator reached its maximum power of 500 W. The results retrieved will be used for the optimization and design of a new enlarged scale turbine–generator assembly. They will also be used as input data for the numerical modeling of the generator. Also, the exact knowledge of the channel geometry and flow parameters is valuable in studies preceding testing a prototype in the site.

Experimental study of 37Cl(α,n)40K reaction in order to constrain the reaction rate of destruction of 40K in stars

40K is one of the main isotopes responsible for the radiogenic heating of the mantle in Earth-like exoplanets [1] and hence, plays a very important role in the internal geophysical dynamics of a planet. The abundance of 40K in the mantle and the core of such planets is not always possible to be determined by astrophysical observations, although constraining the nuclear reaction rates of 40K during stellar evolution can also lead to constraining the present amount of 40K in these planets, which will improve our understanding on the habitability potential of Earth-like exoplanets. This study aims to constrain the 40K(n,α)37Cl reaction rate, one of the two major destruction paths of 40K in stellar nucleosynthesis,by measuring the reverse reaction 37Cl(α,n)40K and applying the principle of detailed balance as we have done before for the 40K (40K(n,p)40Ar reaction rate) [2]. During the first set of measurements we performed differential cross-section measurements of the 37Cl(α,n1γ)40K, 37Cl(α,n2γ)40K and 37Cl(α,n3γ)40K reaction channels, for six different center of mass energies in the range between 5.1 and 5.4 MeV. The experiment took place at the Edwards Accelerator Laboratory of Ohio University. The gamma rays from the reaction channels mentioned above were detected by two LaBr3 scintillators. Using the swinger facility to change the angle of the beam-target system with respect to the detection system, we were able to take measurements for the differential cross-section at six different angles between 20° and 120° in the lab system.

Active modulation of the transmission properties of a far infrared all-dielectric metasurface

All-dielectric metasurfaces with tunable and reconfigurable properties have broad application prospects. Here,an all-dielectric metasurface with a MgF 2 layer and a ZrTe 5 array is measured and simulated (The simulation software is HFSS) A transmission valley V1 (amplitude is 0.21, resonance frequency is 10.18 THz) is achieved based on the localized surface plasmon (LSP) mode coupling between four unit cells without external magnetic field. In the first set of measurements, a magnetic field is applied along the x-axis, the measured transmission valley V1 is reduced and the resonant frequency is stabilized. Moreover, a new transmission valley V2 is excited based on the LSP mode coupling between two unit cells. The amplitude of the transmission valley V2 is dependent on the applied magnetic field. In the second set of measurements, a magnetic field is applied along the 450-axis, the amplitude of the transmission valley V1 is also reduced, and a transmission valley V3 is obtained due to the surface plasmon polarization (SPP) modes coupling. The amplitude of the transmission valley V3 is decreased with the increase of the magnetic field, and the resonance frequency is shifted towards the higher frequencies.

Study of the Elastic Scattering in the d + 11B system for EBS purposes

The implementation of boron in several fields, such as in the creation of p-type semiconductors in electronics, has created the need for the accurate quantitative determination of its depth profile concentrations in near surface layers of various matrices. In the framework of IBA techniques a combination of Elastic Backscattering Spectroscopy, along with Nuclear Reaction Analysis, has been proposed in order to address the current needs for boron depth profiling, focusing on the use of proton beams. Deuteron beams however offer superior mass resolution with similar stopping power values and simultaneous excitation of most light elements. Unfortunately, the lack of experimental datasets concerning the deuteron elastic scattering on boron impedes their use. Thus, in the present work, the first set of measurements for the 11B(d,d0) differential cross section covering the Ed,lab=1300-1860 keV energy range for the backscattering angles of 150ο, 160ο and 170ο were carried out. The study was conducted at the 5.5 MV Tandem Accelerator of the Institute of Nuclear and Particle Physics, in the National Center of Scientific Research “Demokritos”, Athens, Greece. The target was a thin, self-supporting aluminum foil, upon which a thin natB (isotopic ratio: 11B 80.1%, 10B 19.9%) layer was deposited using the sputtering technique at RBI, Zagreb, Croatia, followed by the evaporation of an ultra-thin layer of 197Au on top for normalization and wear protection purposes. The outgoing particles were detected using silicon surface barrier (S.S.B.) detectors and the differential cross sections for elastic scattering were determined from the resulting spectra via the relative technique

Differential Cross-section Measurements for Deuteron Elastic Scattering on 11B

The implementation of boron in several fields, such as in the creation of p-type semiconductors in electronics, has created the need for the accurate quantitative determination of its depth profile concentrations in near surface layers of various matrices. In the framework of IBA techniques, a combination of Elastic Backscattering Spectroscopy (EBS), along with Nuclear Reaction Analysis (NRA), has been proposed in order to address the current needs for boron depth profiling, based on the use of a proton beam. Deuterons offer superior mass resolution with respect to protons, having similar stopping power values, but, unfortunately, the lack of experimental datasets concerning the deuteron elastic scattering on boron impedes their use. Thus, in the present work, the first set of measurements for the 11B(d,d0) differential cross sections covering the Ed,lab=1300-1860 keV energy range for the backscattering angles of 150°, 160° and 170° was carried out. The study was conducted at the 5.5 MV Tandem Accelerator of the Institute of Nuclear and Particle Physics, in the National Center of Scientific Research “Demokritos”, Athens, Greece. The target was a thin, self-supporting aluminum foil, upon which a thin natB (isotopic ratio: 11B 80.1%, 10B 19.9%) layer was deposited using the sputtering technique at RBI, Zagreb, Croatia, followed by the evaporation of an ultra-thin layer of 197Au on top for wear protection and normalization purposes. The outgoing particles were detected using 6 Silicon Surface Barrier (S.S.B.) detectors and the differential cross sections for the elastic scattering were determined from the resulting spectra via the relative measurement technique.

Effects of heat/mass transfer limitations and process exothermicity on the kinetic parameters of the devolatilization and oxidation reactions of wood chars

Thermogravimetric curves of wood char oxidation consist of devolatilization and oxidation, described with a linear and a power-law rate reaction, respectively. The lack of measurement and control of the sample temperature in standard commercial thermogravimetric systems (STGA) can introduce serious deviations from the heating program, originated from heat and mass transfer limitations and reaction exothermicity. This study aims at quantifying the consequent effects on the estimated kinetic constants for beech, fir and spruce wood chars. A first set of measurements is based on a special purpose designed, homemade thermo-analyzer (HMTGA), permitting for an accurate sample temperature control and a rigorous kinetic regime. The second set makes use of a standard commercial thermobalance (STGA). It is found that for heating rates up to 10 K/min spikes in the rate curves disappear for 1 mg samples and the deviations on the activation energies become null or very small (maximum around 1–1.5%), compared with the HMTGA data. However, the order of the oxidation reaction is always lower (by about 15%). Improvements are not observed following further sample mass reduction.

Magneto-stimulation limits in medical imaging applications with rapid field dynamics

Objective. The goal of this work is to extend previous peripheral nerve stimulation (PNS) studies to scenarios relevant to magnetic particle imaging (MPI) and low-field magnetic resonance imaging (MRI), where field dynamics can evolve at kilo-hertz frequencies. Approach. We have constructed an apparatus for PNS threshold determination on a subject’s limb, capable of narrow and broad-band magnetic stimulation with pulse characteristic times down to 40 μs. Main result. From a first set of measurements on 51 volunteers, we conclude that the PNS dependence on pulse frequency/rise-time is compatible with traditional stimulation models where nervous responses are characterized by a rheobase and a chronaxie. Additionally, we have extended pulse length studies to these fast timescales and confirm thresholds increase significantly as trains transition from tens to a few pulses. We also look at the influence of field spatial distribution on PNS effects, and find that thresholds are higher in an approximately linearly inhomogeneous field (relevant to MRI) than in a rather homogeneous distribution (as in MPI). Significance. PNS constrains the clinical performance of MRI and MPI systems. Extensive magneto-stimulation studies have been carried out recently in the field of MPI, where typical operation frequencies range from single to tens of kilo-hertz. However, PNS literature is scarce for MRI in this fast regime, relevant to small (low inductance) dedicated MRI setups, and where the resonant character of MPI coils prevents studies of broad-band stimulation pulses. This work advances in this direction.

Effect of body posture on sound absorption by human subjects

In masjid acoustical design, it is important to consider the effects of different human body postures on its sound absorption characteristics. In this study, 15 male subjects were asked to simulate the four Islamic prayer postures (standing, bowing, prostration, and sitting down) to investigate these effects. Additionally, a fifth posture was considered wherein the participants sat down randomly on the floor, simulating the case of worshippers listening to the Friday sermon. Measurements were performed twice in a reverberation room, following ISO 354:2003. The first set of measurements was performed while the participants simulated prayer directly on the bare floor (Setup 1), whereas the second set was performed while prayer was simulated on a carefully selected masjid carpet installed over a polyethylene foam padding (Setup 2). The results confirmed the human subjects’ ability to absorb sound waves in the mid- and high-frequency bands and highlighted the absorption dependence on body posture. In the mid-frequency band for both setups, standing in well-defined rows yielded the highest equivalent sound absorption area per object, AObj (Setup 1 mean = 0.49 m2, Setup 2 mean = 0.70 m2), whereas prostration in well-defined rows yielded the lowest AObj value (Setup 1 mean = 0.34, Setup 2 mean = 0.54 m2). The effects of clothing and carpets on sound absorption by the human body were also revealed. Finally, different approaches for incorporating these findings in acoustic simulation software were discussed.

Acute hyperventilation increases oxygen consumption and decreases peripheral tissue perfusion in critically ill patients.

This study aimed to evaluate the effects of acute hyperventilation on central venous-to-arterial carbon dioxide tension difference (Pv-aCO2), central venous oxygen saturation (ScvO2), central venous-to-arterial CO2 difference/arterial-central venous O2 difference ratio (CO2GAP-Ratio), and peripheral perfusion index (PI) in hemodynamically stable critically ill patients. Fifty-four mechanically ventilated patients were evaluated. The cardiac index, Pv-aCO2, ScvO2, CO2GAP-Ratio, PI, and arterial and venous blood gas parameters were measured in the first set of measurements. Then, alveolar ventilation was increased by raising the respiratory rate (10 breaths/min). After a 30 min hyperventilation period, the second set of measurements was recorded. Acute hyperventilation induces an increase in Pv-aCO2 (from 3.87 ± 1.31 to 8.44 ± 1.81 mmHg, P < 0.001) and a decrease in ScvO2(from 71.78 ± 4.82 to 66.47 ± 5.74%, P < 0.001). The CO2GAP-Ratio was significantly increased(from 0.97 ± 0.40 to 1.74 ± 0.46, P < 0.001), and the PI showed a remarkable decrease caused by acute hyperventilation(from 1.82 ± 1.14 to 1.40 ± 0.99，P = 0.04). Hyperventilation-induced ∆_Pv-aCO2 was negatively correlated with ∆PaCO2(r = -0.572, P<0.001). The change in ∆_PaCO2 was correlated with ∆_ScvO2(r = 0.450, P<0.001). However, the left ventricular outflow tract velocity time integral (LVOT-VTI) remained unchanged during hyperventilation. Acute hyperventilation induced an increase in oxygen consumption and decreased peripheral tissue perfusion in patients. For critical care patients, it is necessary to pay attention to the influence of hyperventilation on peripheral tissue perfusion indices and oxygen consumption indices.

The impact of glycine on the zeta potential of calcite at different temperatures and brine compositions

This study presents zeta potential (ZP) measurements of synthetic calcite in glycine solutions using the electrophoretic method. We tested samples with glycine concentrations of 1, 3, and 5 wt% at 25°C, while the ZP of 5 wt% glycine solutions was also measured at 50 and 75°C. The first set of measurements consisted of single-component brines prepared with CaCl2, MgCl2, Na2SO4, and NaCl salts with an ionic strength of 0.05 M. The second set of measurements consisted of formation brine (FB) with an ionic strength of 6.37 M and FB diluted 2-, 10-, and 100-times (2dFB, 10dFB, 100dFB, respectively). Results show that the effect of glycine on calcite’s ZP depended on its initial ZP value. Moreover, the increase in temperature significantly decreased calcite’s ZP in most samples. The ZP values in CaCl2 and MgCl2 brines were initially positive and decreased with the addition of glycine. Conversely, the ZP values of calcite in NaCl and Na2SO4 brines were initially negative and increased with the addition of glycine. The trends of ZP versus glycine concentration for 2dFB and 10dFB were analogous to the ones with CaCl2 and MgCl2 brines. Similar trends were observed between 100dFB, NaCl, and Na2SO4 brines. Finally, the increase of temperature from 25°C to 50°C and 70°C significantly reduced the ZP of calcite’s particles in CaCl2, Na2SO4, and NaCl brines, while the ZP of FB and its dilutions slightly decreased at 50°C. This is the first time the ZP measurements of calcite in glycine solutions were reported, to the best of our knowledge. Results are mainly explained by (1) the adsorption of glycine anion onto the calcite’s surface, (2) the decrease of the brine’s pH from the addition of glycine, and (3) the complex formation of glycine with divalent ions. Given the ubiquity and abundance of calcite in nature, we expect this study to increase the understanding of the electrostatic interactions between amino acids and calcite in phenomena such as wettability alteration and biomineralization.

Measurement of the vapour–liquid equilibrium properties of binary mixtures of the low-GWP refrigerants R1123 and R1234yf

The vapour–liquid equilibrium properties of binary mixtures of R1123 and R1234yf, which are key components of the next generation of refrigerant mixtures, were measured using a recirculation-type vapour–liquid equilibrium property measurement apparatus. Two sets of measurements were conducted by two different technicians (co-authors Nishida and Saito) using the same apparatus and sample. The first set of measurements were conducted at temperatures that were close to the integer values in absolute temperature, whereas the second set of measurements was taken at temperatures that were close to the integer values in terms of degrees Celsius. Both sets of measurements were based on the ITS-90 temperature scale and were found to be in good agreement at the measurement temperatures (300 and 330 K). These data were compared with the predictions of a Helmholtz-type equation of state, and a systematic deviation of approximately 8% was observed at low temperatures. A regression analysis using the binary interaction parameter kij of the modified Peng–Robinson equation of state more accurately reproduced the experimental measurements.

Evaluation of the heat changes in an ancient church because of restoration works: A microclimatic study supported by thermal images

This work is centred on an ancient Italian church. Since 2011, a restoration plan has been undertaken by following sequential phases. The methodological approach to restoration was guided by environmental monitoring campaigns. In particular, two thermo-hygrometric campaigns were carried out during the warm months of the years 2015 and 2016. The first set of measurements was executed during the restoration of facades and roofs, making it possible to reach even areas that are usually difficult to access. The second set was performed to evaluate the indoor thermo-hygrometric conditions following the work of the previous year. This was intended to assess their differences in variability, the influence of the outdoor environment and any real and perceived improvement. Results demonstrate that thermal images helped in identifying both the heat sources causing thermal discomforts and the good thermal capacity of masonries. Concerning the heat index (HI), the church showed an improvement in the trend of malaise perceived by people during the second summer period (∼2°C lower than 2015). Finally, in the last microclimate monitoring, the roof structure no longer acted as an amplifier for daily temperature excursions.

Enhanced transmission performance based on ultrathin broadband circular hole array metasurface

A high transmittance broadband metasurface with Si and STO layers is verified in 100–130 THz. This metasurface achieves a transmission peak (Amplitude 78.1%, Resonance frequency 112.2 THz) with a complete Si layer, or a broad transmission band (Average transmittance 82.3%, bandwidth 5.1 THz) with a Si layer defined by a circular hole array. The influence of structural parameters (period P and diameter D) on this transmission band is measured. In the first set of measurements, the average transmittance and bandwidth of this metasurface remain unchanged with P increasing. In the second set of measurements, however, the average transmittance is increased from 82.3% to 92.7%, and bandwidth is enhanced from 5.1 THz to 7.2 THz with D increasing. Finally, the sensitivity of the metasurface to temperature is measured. When temperature increases from 300 K to 360 K, average transmittance increases from 82.3% to 95.4%, and bandwidth enhances from 5.1 THz to 10.3 THz. When temperature reduces, the average transmittance and bandwidth decrease. This metasurface exploits the potential of temperature sensing.

Spent fuel nondestructive assay integrated characterization from active neutron, passive neutron, and passive gamma

Spent nuclear fuel comprises a wide range of irradiated isotopic material compositions, and characterization through nondestructive measurements is beneficial in verifying declared parameters before the fuel is placed in storage, final disposal, and/or reprocessed. This paper discusses results from three nondestructive assay instruments, including passive gamma, passive neutron, and active neutron methods, that measured fifty spent fuel assemblies at the Clab interim storage facility in Sweden. Integrated analysis of the measurements from the three different instruments allowed parametric assessments of cooling time, burnup, neutron multiplication, fissile mass, initial enrichment, and decay heat of each individual fuel assembly. Passive gamma measurements were found to be the most beneficial in predicting cooling time, passive neutron for determining burnup, active neutron in estimating initial enrichment, and both passive and total neutron for multiplication correlations. Fissile mass was best estimated using any combination of any two of the instruments such that corrections for isotopic changes in the fuel could be accounted for with the first set of measurements and multiplication of the assembly in the second. In conclusion, the nondestructive assay technologies demonstrated through this effort enhance the characterization of spent nuclear fuel assemblies.

Performance of a new device for the clinical determination of light discomfort

ABSTRACT Purpose To assess the performance of a new device for the clinical determination of light discomfort on a large sample of healthy human subjects. Methods A total of 489 subjects ranging from 20 to 70 years old (241 men, 248 women) were evaluated with the LUMIZ™ 100 to determine light discomfort. Repeatability was assessed by means of within-subject standard deviation, coefficient of variation (CoV), and intraclass correlation coefficient (ICC). Repeated measures ANOVA, Kruskal-Wallis, and correlation analysis were applied to test for differences between repeated measures, and effect of age on reliability. Results Discomfort thresholds obtained are well distributed across the light intensity range available (25 to 10211 lux). Intrasession ICCs are higher than 0.849 for all thresholds, and 85% of CoV are below 10%. Thresholds obtained in the first set of measurements are highly correlated with the median of three sets (r2 > 0.8). Intersession, 64% of CoV are below 10%. Age does not affect discomfort thresholds (p = 0.30), nor affect reliability (variance on CoV, p = 0.368) Conclusions The new device provides good intrasession repeatability for the clinical determination of light discomfort thresholds, although variance is slightly greater between sessions. The system is useful for the clinical determination of light discomfort.

Unusual behavior of coercivity in Hf/GdFeCo bilayer with MgO cap layer by electric current

We investigate the Hf/GdFeCo bilayer with the MgO cap layer for both rare earth (RE)-rich and transition metal (TM)-rich configurations of the ferrimagnetic sublattice in the presence of the perpendicular field. We study the coercivity using the anomalous Hall effect (AHE) technique by multiple measurements on the same sample. In the first set of measurements and at low electric currents, coercivity sharply drops because of the oxygen diffusion at the interface between MgO and GdFeCo when the AHE probe current is applied. During the subsequent measurements on the RE-rich sample, we observe a moderate decrease in coercivity at low currents and the coercivity increases in a high current range. Such nonlinear dependence of coercivity on electric current can be explained by the competing interplay of the spin–orbit torque (SOT) and the Joule heating effects. On the other hand, for the TM-rich case, the SOT effect is observed over a widely applied current range.

Verification of the Canadian Laboratory Initiative on Paediatric Reference Intervals (CALIPER) reference values in Croatian children and adolescents.

IntroductionThe aim of this study was to examine whether the Canadian Laboratory Initiative on Paediatric Reference Intervals (CALIPER) could be applied to Croatian children and adolescents.Materials and methodsA total of 295 outpatient healthy children and adolescents of age 1 to 18 were selected using the direct a posteriori sampling method. According to current guidelines, 20 samples were tested for each of a total of 51 reference intervals for ferritin, cortisol, dehydroepiandrosterone sulfate, follicle stimulating hormone, lutein stimulating hormone, prolactin, progesterone, sex hormone binding globulin, thyroid stimulating hormone, total testosterone, total thyroxine and total triiodothyronine. Serum samples were analysed on the Beckman Coulter DxI600 immunoassay analyser by chemiluminescence immunoassay method. A reference interval was adopted if < 10% of the results fall outside CALIPER reference interval range. For analytes in which this criterion is not met in the first set of samples, a new set of 20 samples were collected.ResultsAfter the first set of measurements, 96% of all tested reference intervals were adopted for use. The additional sets of 20 reference subjects were tested for only two reference intervals; follicle stimulating hormone for female aged 1 to 9 years, and irrespective of the gender, sex hormone binding globulin for children aged 8 to 11 years. All results of additional samples were within the specified interval limits.ConclusionsCALIPER reference intervals for ferritin and 11 hormones defined for Beckman Coulter DxI600 immunoassay analyser can be implemented into the Croatian laboratories and clinical practice.