Novel Algorithm for the Differential Diagnosis of Hyponatraemia in Anuric Patients Undergoing Maintenance Haemodialysis

<b><i>Introduction:</i></b> Hyponatraemia is associated with increased mortality in patients undergoing maintenance haemodialysis. In anuric patients, hyponatraemia development depends on the water-sodium ratio in retained fluid within the interdialysis interval (IDI). <b><i>Objective:</i></b> This study aimed to calculate the retained sodium-retained water ratio in patients on maintenance haemodialysis and make a differential diagnosis of hyponatraemia according to these data. <b><i>Methods:</i></b> The amount of retained water was determined as body weight gain (ΔBW) within the IDI. Sodium retention was calculated using our formula: eRNa⁺ = ΔBW × (SNa⁺)_t2 − total body water (TBW)_t1 × ([SNa⁺]_t1 − [SNa⁺]_t2), where TBW represents the calculated volume of the total body water and (SNa⁺)_t1 and (SNa⁺)_t2 represent the sodium concentration at the beginning and at the end of the IDI, respectively. We performed 89 measurements in 32 anuric patients on maintenance haemodialysis. <b><i>Results:</i></b> Hyponatraemia was detected in 13 measurements at the end of the IDI. The ΔBW had no statistically significant difference between normonatraemic and hyponatraemic patients. Hyponatraemic patients had significantly lower levels of retained sodium. The retained water-­retained sodium ratio facilitated in differentiating dilution hyponatraemia, nutritional hyponatraemia, depletion hyponatraemia, and dilution hyponatraemia associated with sodium wasting or malnutrition. <b><i>Conclusion:</i></b> The composition of retained fluid during the IDI may be hypotonic, hypertonic, or isotonic in relation to the extracellular fluid. Most of the hyponatraemic patients had hypotonic fluid retained during the IDI because of dilution as well as gastrointestinal sodium loss and/or malnutrition.

Effect of Wetting Conditions on the In Situ Density of Soil Using the Sand-Cone Method

The sand-cone method is commonly used to measure the in situ density of compacted soils. While determining field density with this method, differences in the sand-filling process between the test hole and the calibration container can cause errors. The differences can result from various in situ conditions such as the shape and size of the test hole and the moisture conditions of the filling sand and test ground. Temporary rainfall can increase the moisture content of both in situ soils and filling sand. This study examined the effect of wetting conditions on the accuracy of the sand-cone method in a laboratory. Compacted soils with different water contents (2–16%) were prepared in a small circular container in the laboratory, and the sand-filling process was simulated for cylindrical, conical, and roof-shaped test holes with depths of 10 and 15 cm. As the water content of the compacted soils increased, the sand-cone method underestimated the volume of sand accumulated in the test holes by up to 20%, resulting in the calculated density being overestimated by an identical amount. Slightly moist sand was poured into artificial test holes. When the water content of the filling sand was below 1%, no significant error was observed in the calculated volume.

THE SIMULATION OF VIBRATIONAL POPULATIONS OF ELECTRONICALLY EXCITED N2 IN TITAN’S UPPER ATMOSPHERE DURING PRECIPITATIONS OF HIGH-ENERGETIC PARTICLES

We study the electronic kinetics of singlet molecular nitrogen in Titan’s upper atmosphere during precipitations of high-energetic particles. Both radiative processes and processes of electron excitation energy transfer during inelastic collisions with N2 and CH4 molecules were considered in the calculation of vibrational populations of electronically excited singlet states a'1Σu–, a1Πg, w1Δu of molecular nitrogen in the upper atmosphere of Titan. It is shown that the calculated volume emission intensities of the Lyman-Birge-Hopfield bands correlate with the profiles of the ion production rate in the atmosphere of Titan during the considered cases of electron precipitation for considered interval of the energies 30-1000 eV of magnetospheric electrons. This fact is explained by the negligible contribution of collisional processes to the vibrational populations a1Πg(v'=0-6) in the considered range of heights above 900 km.

Improving the Supply System Gas Engine to Improve Energy Efficiency

The paper presents the main advantages and disadvantages of standard fuels in comparison with alternative fuels of methane series used in internal combustion engines. Particular attention in the article is given to the study of the heat transfer parameters of the calculated volume in the fuel tank filled with liquefied methane with thermal insulation, as well as methane outflow in special round tubes to transport gas in the liquid phase to the atomizer of the gas injector. Variants of numerical modeling of phase transitions of the heterogeneous system inside the tank are presented, as the calculated volume and flow of a two-phase flow of liquefied methane in tubes in the horizontal plane, taking into account the operating parameters of the elements of the fuel supply system.

Particle Size and Pre-Treatment Effects on Polystyrene Microplastic Settlement in Water: Implications for Environmental Behavior and Ecotoxicological Tests

Microplastic (MP) particle dispersions used in many recent publications covering adsorption or toxicological studies are not characterized very well. The size distribution of polydisperse dispersions is highly dependent on the agglomeration processes and influences experimental outcomes. Therefore, pre-treatment is a prerequisite for reproducibility. In this study, manual/automated shaking and ultrasonic treatment as different mechanical dispersion techniques were applied for the dispersion of cryomilled polystyrene (PS). Particle numbers and size distribution of dispersions were analyzed by a light extinction particle counter and the dispersion efficiency (ED) as the ratio between calculated volume and theoretical volume of suspended particles was used to compare techniques. PS dispersions (20 mg/L) treated for 90 min in an ultrasonic bath (120 W, 35 kHz) were evenly dispersed with a particle concentration of 140,000 particles/mL and a high reproducibility (rel. SD = 2.1%, n = 6). Automated horizontal shaking for 754 h (250 rpm) reached similar particle numbers (122,000/mL) but with a lower reproducibility (rel. SD = 9.1%, n = 6). Manual shaking by hand dispersed the lowest number of particles (55,000/mL) and was therefore found to be unsuitable to counteract homo-agglomeration. ED was calculated as 127%, 104% and 69% for ultrasonic treatment, horizontal shaking and manual shaking, respectively, showing an overestimation of volume assuming spherical shaped particles.

Impact of Dexmedetomidine on Tourniquet-Induced Systemic Effects in Total Knee Arthroplasty under Spinal Anesthesia: a Prospective Randomized, Double-Blinded Study

Background. Clinical studies on the impact of dexmedetomidine on tourniquet-induced systemic effects have been inconsistent. We investigated the impact of dexmedetomidine on tourniquet-induced systemic effects in total knee arthroplasty. Methods. Eighty patients were randomly assigned to either control (CON) or dexmedetomidine (DEX) group. The DEX group received an intravenous loading dose of 0.5 μg/kg DEX over 10 minutes, followed by a continuous infusion of 0.5 μg/kg/h from 10 minutes before the start of surgery until completion. The CON group received the same calculated volume of normal saline. Pain outcomes and metabolic and coagulative changes after tourniquet application and after tourniquet release were investigated. Results. The frequency of fentanyl administration postoperatively, patient-controlled analgesia (PCA) volume at 24 hours postoperatively, total PCA volume consumed in 48 hours postoperatively, and VAS score for pain at 24 and 48 hours postoperatively were significantly lower in the DEX group than in the CON group. Ten minutes after the tourniquet release, the DEX group showed significantly higher pH and lower lactate level than those in the CON group. Antithrombin III activity and body temperature 10 minutes after tourniquet release were significantly lower in the DEX group than in the CON group. Ca2+, K+, HCO3-, base excess, and PCO2 levels 10 minutes after tourniquet release were not significantly different between the two groups. Conclusion. We showed that DEX attenuated pain and hemodynamic, metabolic, and coagulative effects induced by the tourniquet. However, these metabolic and coagulative changes were within normal limits. Therefore, DEX could be used as an analgesic adjuvant, but should not be considered for routine use to prevent the systemic effects induced by tourniquet use.

Effect of Extreme Temperature on Naloxone Nasal Spray Dispensing Device Performance

Introduction:The opioid epidemic has led to the wide-spread distribution of naloxone to emergency personnel and to the general public. Recommended storage conditions based on prescribing information are between 15°C and 25°C (59°F and 77°F), with excursions permitted between 4°C and 40°C (39°F and 104°F). Actual storage likely varies widely with potential exposures to extreme temperatures outside of these ranges. These potentially prolonged extreme temperatures may alter the volume of naloxone dispensed from the nasal spray device, which could result in suboptimal efficacy.Study Objective:The aim of this study was to assess the naloxone volume deployed following nasal spray device storage at extreme temperatures over an extended period of time.Methods:Naloxone nasal spray devices were exposed to storage temperatures of −29°C (−20°F), 20°C (68°F), and 71°C (160°F) to simulate extreme temperatures and a control for 10 hours. First, the density was measured under each temperature condition. Following the density calculation part of the experiment, the mass of naloxone dispensed from each nasal spray device at each temperature was captured and used to calculate volume: calculated volume (microliter, µl) = spray mass (mg converted to g)/mean density (g/mL). Measurements and calculations are reported as means with standard deviation and standard error, and a one-way ANOVA was used to evaluate mean dispensed volume differences at different temperatures.Results:There was no difference in the mean volume deployed at −29°C (−20°F), 20°C (68°F), and 71°C (160°F), and measurements were 101.44µl (SD = 9.56; SE = 5.52), 99.01µl (SD = 6.31; SE = 3.64), and 108.28µl (SD = 2.04; SE = 1.18), respectively; P value = .289, F-statistic value = 1.535.Conclusion:The results of this study suggest that naloxone nasal spray devices will dispense the appropriate volume, even when stored at extreme temperatures outside of the manufacturer’s recommended range.

Preserving Vision: Rethinking Burn Patient Monitoring to Prevent Orbital Compartment Syndrome

Burn patients receiving aggressive fluid resuscitation are at risk of developing orbital compartment syndrome (OCS). This condition results in elevated orbital pressures and can lead to rapid permanent vision loss. Risk factors and monitoring frequency for OCS remain largely unknown. A retrospective review was therefore conducted of admitted burn patients evaluated by the ophthalmology service at an American Burn Association verified Burn Treatment Center. Demographic, burn, examination, and fluid resuscitation data were compared using two-sided t-tests, Fisher’s exact tests, and linear regression. Risk factors for elevated intraocular pressures (IOPs; a surrogate for intraorbital pressure) in patients resuscitated via the Parkland formula were found to be total body surface area (% TBSA) burned, resuscitation above the Ivy Index (&gt;250 ml/kg), and Parkland formula calculated volume. Maximum IOP and actual fluid resuscitation volume were linearly related. Analysis of all patients with elevated IOP found multiple patients with significant IOP increases after initial evaluation resulting in OCS within the first 24 hours postinjury. While %TBSA, Ivy Index, and resuscitation calculated volume are OCS risk factors in burn patients, two patients with facial burns developed OCS (25% of all patients with OCS) despite not requiring resuscitation. Orbital congestion can develop within the first 24 hours of admission when resuscitation volumes are the greatest. In addition to earlier and more frequent IOP checks in susceptible burn patients during the first day, the associated risk factors will help identify those most at risk for OCS and vision loss.

DETERMINATION OF VOLUMES OF MELT AND SLAG DURING MELTING IN THE ORE-THERMAL FURNACE

Analysis of recent research and publications. Problematic issues of theory and technology of production of ferroalloys, improvement of structures of ore-thermal electric furnaces, optimization of electric modes of melting are constantly discussed at the relevant international congresses. For a more accurate reflection of the actual physical processes occurring in the working space of the bath, it is necessary to take into account that when the mixture is heated its density changes and occurs between the phase transition.The aim of the study. The purpose of this work is to simulate the process of transition of the charge in the melt, with the subsequent possibility of more accurate determination of some its parameters in the dynamics.Presentation of the main research material. Bath OTF is complex in its structure. It contains a mixture of various physical and chemical conditions (from solid pieces to doughy magma), slag and metal. The physical processes that take place are very different. Some of them are continuous, and others, which are carried out before full melting of single-loaded materials.In order to simulate the process of formation of a melt in a bath of an ore-thermal furnace it is proposed to break its inner space into elementary volumes. We have chosen and slightly modified the method based on the system of cylindrical coordinates, according to which the furnace bath is regarded as a cylinder. We will place further calculation points in the geometric centers of these volumes.The transition of the charge from the solid to the liquid phase is determined by the temperature at which the melting of different types of ferroalloys occurs. If this is the case, knowing the mass and density of the liquid melt and slag at a given temperature, we calculate their real volume, obtained as a result of these phase transitions, in one elementary volume. Thereafter, the total melt volume and charge formed over a given period of time is calculated.During the phase transition, the charge is converted into a melt and slag resulting in its settling down to the bottom of the ore-thermal furnace bath. The maximum permissible amount of charge settling near the electrodes is strictly regulated by the technical documentation of the furnace, so if the calculated value has reached this value, the charge of the charge under the electrodes should be made.It is also possible to compare the calculated volume of the formed melt over the melting interval with its predetermined value. If these indicators are already the same, then it is necessary to merge the melt and slag, otherwise we go to the next period of time and perform these calculations until the specified condition is fulfilled.Conclusions. With a comprehensive approach to the process of modeling the operation of OTF, one of the tasks is to determine the amount of molten metal in the bottom of the bath. This question is solved by the presented methodology and algorithm, which give an opportunity to find out how much melt there is at one or another time during the operation of the furnace.

Evaluating the Consistency of All Submicron Aerosol Mass Measurements (Total and Speciated) for the NASA Atmospheric Tomography Aircraft Mission (ATom)

&lt;p&gt;The Aerodyne Aerosol Mass Spectrometer (AMS) is a widely used instrument to quantify the composition of non-refractory submicron aerosol, in particular, organic aerosol (OA). Past comparisons, particularly of aircraft data in continental areas, have shown good overall agreement with other chemical and optical sensors. Recently, theoretically-based concerns have been raised regarding the overall AMS calibration uncertainties (particularly for OA), although there is no evidence that those apply to aircraft datasets.&lt;/p&gt;&lt;p&gt;The ATom mission sampled the remote marine troposphere from 87S to 82N and from 0 to 12.5 km over the course of four aircraft deployments over the space of 2 years, carrying an advanced aerosol payload that included particle sizing instruments operated by NOAA ESRL, as well as several chemical sensors: UNH Mist Chamber and Filters for inorganic aerosol, NOAA SP2 for black carbon measurements, NOAA PALMS instrument for single particle composition and the CU aircraft high-resolution AMS for non-refractory submicron mass. This provides a unique opportunity to explore the agreement of the different instruments over a very large range of conditions and calibration regimes, and improve our understanding of the various instrumental uncertainties in field data.&lt;/p&gt;&lt;p&gt;Special attention was paid to characterize the AMS size-dependent transmission with in-field calibrations; this provided crucial context when comparing with instruments with very different size cuts. Excellent agreement was found between the AMS calculated volume (including black carbon from the SP2) and the PM1 volume derived from the NOAA particle sizing measurements over three orders of magnitude (slope 0.94). The comparisons for sulfate, OA, and seasalt (the three main components of the remote PM1 aerosol) measured by AMS with the PALMS instrument showed similar consistency once differences in particle detection at different sizes were accounted for. Similarly, comparisons with sulfate from filters showed good consistency once episodes with large supermicron mass were filtered out. Comparisons of the AMS with the mist chamber sulfate were affected by the variable time response of the latter instrument but were overall consistent. Overall, no evidence for AMS calibration artifacts or unknown sources of error was found for these datasets. A comprehensive evaluation of the different sources of uncertainty and their impact on the comparisons was performed, and factors to be considered for performing such intercomparisons and improving the reliability of submicron mass quantification in the future are discussed.&lt;/p&gt;