Acid freezes uricolysis in addition to glycolysis: Utility of fluoride-EDTA-citrate tube in the measurement of uric acid for patients administered rasburicase

Background In samples from patients administered rasburicase, ex vivo uricolysis leads to spuriously low uric acid results. The manufacturer’s recommendation of storing the sample in ice-water until analysis, however, does not fully arrest uricolysis. Since uricase activity is affected by pH and metal chelators, we assessed uricolysis inhibition in sodium fluoride-ethylenediaminetetraacetic acid (EDTA)-citrate sample tube (FC Mix tube, Greiner) used primarily for plasma glucose. Method A serum pool was spiked with rasburicase and uric acid measured at 15, 45, 90, 150, 240 and 1080 min in a lithium heparin tube in ice-water, plain tube at room temperature (RT), EDTA tube at RT, FC Mix tube in ice-water, FC Mix tube at RT and FC Mix tube at RT prepared by dissolving FC Mix in serum. Results The rate of urate decay was lowest in the FC Mix tube independent of temperature, then lithium heparin tube in ice-water, then EDTA tube at RT and highest in the plain tube at RT. Uric acid concentrations in the prepared FC Mix tube at RT and heparin tube in ice-water were, respectively, 98.2% and 93.8% of control values at 90 min, 97.1% and 89.3% of control values at 4 h, and remained higher in the prepared FC Mix tube at all time points. Conclusion NaF-EDTA-citrate mixture largely arrested rasburicase mediated ex vivo uricolysis without the need for sample cooling. We propose that sample tubes containing NaF-EDTA-citrate be used for the measurement of uric acid in patients administered rasburicase.

Structure–Property Relationship in Melt-Spun Poly(hydroxybutyrate-co-3-hexanoate) Monofilaments

Poly(hydroxybutyrate-co-3-hexanoate) (PHBH) is a biodegradable thermoplastic polyester with the potential to be used in textile and medical applications. We have aimed at developing an upscalable melt-spinning method to produce fine biodegradable PHBH filaments without the use of an ice water bath or offline drawing techniques. We have evaluated the effect of different polymer grades (mol% 3-hydroxy hexanoate, molecular weight etc.) and production parameters on the tensile properties of melt-spun filaments. PHBH monofilaments (diameter < 130 µm) have been successfully melt-spun and online drawn from three different polymer grades. We report thermal and rheological properties of the polymer grades as well as morphological, thermal, mechanical, and structural properties of the melt-spun filaments thereof. Tensile strengths up to 291 MPa have been achieved. Differences in tensile performance have been correlated to structural differences with wide-angle X-ray diffraction and small-angle X-ray scattering. The measurements obtained have revealed that a synergetic interaction of a highly oriented non-crystalline mesophase with highly oriented α-crystals leads to increased tensile strength. Additionally, the effect of aging on the structure and tensile performance has been investigated.

Optimization of Maintenance Management Indicators in a Chilled Water Plant

The academic sector, like any other service or industrial sector, requires constant innovation in each of its processes. In Colombia, the Universidad EAFIT, as part of the search for new ways of teaching and learning, has recognized the significance of making learning spaces suitable for the people involved in this process. In consequence, the project described in this chapter shows the most efficient methodology for the optimization of asset management for the Universidad EAFIT's Ice Water Plant. The methodologies used include key concepts and factors such as availability, maintainability, and reliability in the costs related to the behavior and nature of the failures, having as reference an integral model of the maintenance management process. The objective of this project is to maintain these high standards of operation and maintenance throughout the useful life of the system and to show the importance that maintenance and the methodologies associated with it have in any sector or industry.

January 26 — International Day «Let's Talk»

January marks the beginning of the new year and the middle of winter, therefore, the holidays this month are celebrated accordingly, for example, in Canada and the United States, Walrus Day is celebrated on January 1 with the organization of traditional swims in ice water, but on January 5, it was proposed to celebrate Fasting Day, obviously, with the purpose of saving the body tired from the festive feasts. On January 14, in some countries, it is customary to celebrate an unusual day — the Day of Combating Procrastination, which in psychology means «constantly putting things off for later», some experts have already dubbed this fairly common feature «the disease of the 21st century». January 16 isWorld SnowDay and January 21 is International Hug Day. Besides, on the last Wednesday of January, concerned people proposed to establish Let's Talk Day, dedicated to the problem of difficult relationships between healthy people and patients with mental disorders. Canada was the initiator of the celebration of this day. Experts suggest that ordinary people protect themselves from mental illness by leading an active lifestyle, but does it always help? Let's try to figure it out in this article.

Autonomous System for Lake Ice Monitoring

Continuous monitoring of ice cover belongs to the key tasks of modern climate research, providing up-to-date information on climate change in cold regions. While a strong advance in ice monitoring worldwide has been provided by the recent development of remote sensing methods, quantification of seasonal ice cover is impossible without on-site autonomous measurements of the mass and heat budget. In the present study, we propose an autonomous monitoring system for continuous in situ measuring of vertical temperature distribution in the near-ice air, the ice strata and the under-ice water layer for several months with simultaneous records of solar radiation incoming at the lake surface and passing through the snow and ice covers as well as snow and ice thicknesses. The use of modern miniature analog and digital sensors made it possible to make a compact, energy efficient measurement system with high precision and spatial resolution and characterized by easy deployment and transportation. In particular, the high resolution of the ice thickness probe of 0.05 mm allows to resolve the fine-scale processes occurring in low-flow environments, such as freshwater lakes. Several systems were tested in numerous studies in Lake Baikal and demonstrated a high reliability in deriving the ice heat balance components during ice-covered periods.

ХАРАКТЕР ХИМИЧЕСКОЕ ВЗАИМОДЕЙСТВИЕ И СТЕКЛООБРАЗОВАНИЕ В СИСТЕМЕ AS2SE3-IN2TE3

Mетодами дифференциально-термического (ДТА), рентгенофазового (РФА), микроструктурного (МСА) анализа, а также измерения микротвердости и плотности, исследована система As2Se3-In2Te3 и построена Т - х фазовая диаграмма. Система As2Sе3-In2Te3 является квазибинарным сечением тройной взаимной системы As,In//Sе,Te. Cоединение In2As2Se3Te3 кристаллизуется в тетрагональной сингонии с параметрами решетки: а =9,40; с =6,36 Å, плотность ρпикн.=5,36 г/см3, ρрент.=5,85 г/см3. В системе образуется одно инконгруэнтное соединение In2As2Sе3Te3,плавящееся при 620оС. Выявлено, что в системе твердые растворы на основе In2Te3 доходят до 3 мол. %, а на основе As2Sе3 практически не обнаружены. В системе при медленном охлаждении область стеклообразования на основе As2Sе3 доходит до 7 мол. % In2Te3, а в режиме закалки в ледяной воде около 12 мол. % In2Te3. By the methods of differential thermal (DTA), X-ray phase (XRD), microstructural (MSA) analysis, as well as measurements of microhardness and density, the As2Se3-In2Te3 system was investigated and the T-x phase diagram was constructed. The As2Sе3-In2Te3 system is a quasi-binary section of the ternary reciprocal system As, In // Se, Te. One incongruent compound In2As2Sе3Te3 is formed in the system, melting at 620оС. Compound In2As2Sе3Te3 crystallizes in the tetragonal system with lattice parameters: a = 9.40; с = 6.36 Å, density ρpycn. = 5.36 g/cm3, ρX-rey. = 5.85 g/cm3. It was found that in the system, solid solutions based on In2Te3 reach 3 mol. %, and practically not found on the basis of As2Sе3. In the system, upon slow cooling, the glass formation region based on As2Se3 reaches 7 mol. % In2Te3, and in the mode of quenching in ice water about 12 mol. % In2Te3.

Melting temperature of ice and total gas content of water at the ice-water interface above subglacial Lake Vostok

It is generally assumed that the gas composition and the total gas content of Lake Vostok’s water are, to a large extent, governed by the budget of atmospheric gases entering the lake together with glacier ice melt, mostly in its northern part. Since the ice accretion that prevails in the south of the lake leads to the exclusion of gases during the freezing process, these gases can build up in the lake water. Earlier theoretical works [2, 3] have demonstrated that about 30 water residence times are required to attain equilibrium between gases in solution and those in a hydrate phase, which sets the upper bounds of concentrations of nitrogen and oxygen dissolved in sub-ice water (~2.7 g N2 L–1 and ~0.8 g O2 L–1). Here we attempt to estimate the real gas content of the lake water based on the link between the pressure melting temperature of ice and the concentration of gases dissolved in the liquid phase [2]. We use the stacked borehole temperature profile extended to 3753 m depth and the measurements of temperature of sub-ice water that entered the borehole after the second unsealing of Lake Vostok to estimate the melting temperature of ice (–2.72 ± 0.1 °C) at the ice sheet-lake interface (depth 3758.6 ± 3 m, pressure 33.78 ± 0.05 MPa). The gas content of the near-surface layer of lake that corresponds to this melting temperature is calculated to be 2.23 g.L–1, meaning that the concentration of dissolved oxygen must be as high as 0.53 g.L–1, i. e. one-two orders of magnitude higher than in any other known water bodies on our planet. The inferred gas content of sub-ice water is, by a factor of 1.6, lower than the maximal solubility of air in water in equilibrium with air hydrate, though it is still higher, by a factor of 19, than the total air content of melting glacier ice. The relatively low concentration of dissolved air in the near-surface layer of the lake revealed in this study provides a new experimental constraint for understanding the gas distribution in Lake Vostok as affected by the circulation and mixing of water beneath the ice sheet.