Reprocessing high‐flux polysulfone dialyzers does not negatively impact solute removal in short‐daily online hemodiafiltration

There are no studies evaluating the impact of dialyzer reprocessing on solute removal in short‐daily online hemodiafiltration (OL‐HDF). Our aim was to evaluate the impact of dialyzer reuse on solute removal in daily OL‐HDF and compare with that in high‐flux short‐daily hemodialysis (SDH). Fourteen patients undergoing a SDH program were included. Pre‐dialysis and post‐dialysis blood samples and effluent dialysate were collected in the 1st, 7th, and 13th dialyzer uses in SDH sessions and in daily OL‐HDF sessions. Directly quantified small solute (urea, phosphorus, creatinine, and uric acid) total mass removal (TM_DQ) and clearance (K_DQ) were similar when the 1st, 7th, and 13th dialyzer SDH uses were compared with the 1st, 7th, and 13th daily OL‐HDF uses. TM_DQ and K_DQ of small solutes were similar among analyzed dialyzer uses in SDH sessions and in daily OL‐HDF sessions. β₂‐Microglobulin TM_DQ and K_DQ were statistically higher in daily OL‐HDF dialyzer uses than in the respective SDH uses. There was no difference in β₂‐microglobulin TM_DQ and K_DQ among dialyzer uses in daily OL‐HDF sessions or in SDH sessions. In daily OL‐HDF, albumin loss was significantly different among dialyzer uses (P < 0.001), being lower in the 7th and 13th dialyzer uses than in the first use. Dialyzer reprocessing did not impair solute extraction in daily OL‐HDF. β₂‐Microglobulin removal was greater in daily OL‐HDF than in SDH sessions, without significant differences in other solutes extraction. There was a significant reduction in intradialytic albumin loss with dialyzer reprocessing in daily OL‐HDF sessions.     

Multiwavelength Raman microspectroscopy for rapid prediction of soot oxidation reactivity

Multiwavelength Raman microspectroscopy (MWRM) analysis for characterization of soot structure and reactivity was developed. This new method is based on the dispersive character of carbon D mode in Raman spectra (i.e., red shift and increase in intensity at higher excitation wavelength, λ(0)). The approach was proven by investigating various diesel soot samples and related carbonaceous materials at different λ(0) (785, 633, 532, and 514 nm). In order to compare the behavior of the D mode for various samples and to derive a single parameter characterizing the soot structure, the difference of integrals for pairs of spectra collected at different λ(0) was calculated. MWRM analysis revealed substantial differences in the structural ordering which decreases from graphite, over Printex XE2 and various diesel soot samples, to spark discharge soot. To obtain the relation between structure and reactivity of soot, MWRM analysis was combined with temperature-programmed oxidation (TPO). TPO allowed us to characterize the oxidation behavior of soot in terms of the maximum emission (CO + CO(2)) temperature and reactivity index. The latter was calculated by introducing the reactivity limits: spark discharge soot containing a large amount of disorder represents the upper limit, whereas the lower limit is given by graphite powder with high structural order. The comparison of MWRM (viz., the observed Raman difference integrals) and TPO data revealed a linear correlation between soot structure and oxidation reactivity. Thus, we demonstrated for the first time the potential of MWRM for a robust and rapid prediction of diesel soot reactivity based on the structure-reactivity correlation.     

Surface plasmon resonance biosensor screening method for paralytic shellfish poisoning toxins: a pilot interlaboratory study

A surface plasmon resonance (SPR) optical biosensor method was developed for the detection of paralytic shellfish poisoning (PSP) toxins in shellfish. This application was transferred in the form of a prototype kit to seven laboratories using Biacore Q SPR optical biosensor instrumentation for interlaboratory evaluation. Each laboratory received 20 shellfish samples across a range of species including blind duplicates for analysis. The samples consisted of 4 noncontaminated samples spiked in duplicate with a low level of PSP toxins (240 μg STXdiHCl equivalents/kg), a high level of saxitoxin (825 μg STXdiHCl/kg), 2 noncontaminated, and 14 naturally contaminated samples. All 7 participating laboratories completed the study, and HorRat values obtained were <1 demonstrating that the method performance was acceptable. Mean recoveries expressed as STXdiHCl equivalents/kg were 94.6 ± 16.8% for the low level PSP toxin mix and 98.6 ± 5.6% for the high level of saxitoxin. Relative standard deviations for within-laboratory variations (RSD(r): repeatability) and between-laboratory variations (RSD(R) = reproducibility) ranged from 1.8 to 9.6% and 2.9 to 18.3% respectively. This first ever reported SPR biosensor interlaboratory study demonstrated this PSP application to be an empowering tool in the drive toward the reduction and replacement of the mouse bioassay within Europe.     

Piezo-optic, photoelastic, and acousto-optic properties of SrB4O7 crystals

On the basis of studies of the piezo-optic effect, it has been shown that SrB(4)O(7) crystals can be used as efficient acousto-optic materials in the vacuum ultraviolet spectral range. The full matrices of piezo-optic and photoelastic coefficients have been experimentally obtained for these crystals. The acousto-optic figure of merit and the diffraction efficiency have been estimated for both the visible and deep ultraviolet spectral ranges.     

Research progress on the regulation of oxidative stress by phenolics: the role of gut microbiota and Nrf2 signaling pathway

In recent years, the increase in high-calorie diets and sedentary lifestyles has made obesity a global public health problem. An unbalanced diet promotes the production of proinflammatory cytokines and causes redox imbalance in the body. Phenolics have potent antioxidant activity and cytoprotective ability. They can scavenge free radicals and reactive oxygen species, and enhance the activity of antioxidant enzymes, thus combating the body's oxidative stress. They can also improve the body's inflammatory response, enhance the enzyme activity of lipid metabolism, and reduce the contents of cholesterol and triglyceride. Most phenolics are biotransformed and absorbed into the blood after the action by gut microbiota; these metabolites then undergo phase I and II metabolism and regulate oxidative stress by scavenging free radicals and increasing expression of antioxidant enzymes. Phenolics induce the expression of genes encoding antioxidant enzymes and phase II detoxification enzymes by stimulating Nrf2 to enter the nucleus and bind to the antioxidant response element after uncoupling from Keap1, thereby promoting the production of antioxidant enzymes and phase II detoxification enzymes. The absorption rate of phenolics in the small intestine is extremely low. Most phenolics reach the colon, where they interact with the microbiota and undergo a series of metabolism. Their metabolites will reach the liver via the portal vein and undergo conjugation reactions. Subsequently, the metabolites reach the whole body to exert biological activity by traveling with the systemic circulation. Phenolics can promote the growth of probiotics, reduce the ratio of Firmicutes/Bacteroidetes (F/B), and improve intestinal microecological imbalance. This paper reviews the nutritional value, bioactivity, and antioxidant mechanism of phenolics in the body, aiming to provide a scientific basis for the development and utilization of natural antioxidants and provide a reference for elucidating the mechanism of action of phenolics for regulating oxidative stress in the body. © 2023 Society of Chemical Industry.     

Fast Fluorescence Spectroscopy Methodology to Monitor the Evolution of Extra Virgin Olive Oils Under Illumination

Detailed regions of excitation and emission wavelengths for extra virgin olive oil samples have been extracted from three dimensional front-face fluorescence spectra. Information was applied to establish a right-angle fluorescence procedure. A right-angle device was assembled and tested with simultaneous excitation from 200 to 400 nm and registration of the fluorescence signal emitted from 400 to 850 nm. A principal component analysis was performed on the signal ranging from 400 to 550 nm from spectra of olive oils officially categorized as extra virgin in order to model the expected variability of compounds related to oxidative processes. Such model was useful to monitor the spectral evolution of extra virgin olive oil samples acquired at retail markets, which were exposed to indirect light during 2 months, through the analysis of the effect on their scores. Three relevant peaks characterized such evolution, with local maxima at around 434 to 437, 464 to 469 and 510 to 518 nm. Polynomial relationship was found between the evolution of those peaks and that of the chlorophyll, at around 670 to 673 nm, with R ² values of 0.98 and 0.99.     

Application of zeolitised coal fly ashes to the depuration of liquid wastes

In this study, the application of some zeolitised fly ashes and synthetic zeolites to the decontamination of the leachate produced in a municipal solid waste (MSW) treatment plant and to the liquid waste from a pig farm was analyzed. Thus, the reduction of organic matter (BOD and COD), ammonium and total nitrogen, phosphorus and metals contents after a zeolite treatment was evaluated. Several synthetic zeolites were tested: some commercial zeolites and other synthetic zeolites and zeolitised ashes obtained after a coal fly ash alkaline hydrothermal process. Two forms of contact between the zeolitic material and the liquid waste were tested: in a stirred tank and in a column. In addition, other variables determined were the amount of zeolite and the residence time. The results showed that zeolites, especially zeolitised fly ash, clearly produced a strong reduction in the leachate nitrogen and phosphorus content.     

Use of Weibull distribution statistics in assessing long term compatibility of propellants with polymeric materials

The long term compatibility of propellants with polymers may be evaluated by statistical means. The Weibull distribution function was used in an effort to provid a more accurate means of estimating the effect of aging of the inert material in contact with the propellant.This method was applied to several systems exhibiting different degrees of compatibility. Exposure at 140°F of the RTV 680 rubber with M30 propellant in the XM735 projectile displayed no apparent adverse effects. Distribution analysis supported the conclusion that the RTV 680/M30 system is compatible at ambient temperatures. Another silicone displayed an initial decline in mechanical properties followed by a period of stability when stored with M30 at elevated temperatures over a period of 12 months.A fair amount of incompatibility was displayed by 30% glass filled nylon which had been exposed to a double base propellant WC870 for an extended time. The Weibull distribution plots indicate that the propellant exerts a damaging effect on both Nylon 12 materials, particularly at elevated temperatures.Thermal aging may contribute to the ultimate failure of a polymer, as well as direct contact with an energetic. This is illustrated in the case of the M205 non-metallic cartridge case used in the projectile of a 152mm round, with M26E1 propellant. Although it is difficult to separate the effect of these variables upon the lifetime of the system, Weibull statistics provide some measure of prediction.     

Percussion hole drilling of metals with a fourth-harmonic Nd:YAG laser studied by defocused laser speckle correlation

Defocused speckle correlation is introduced as a tool for measuring the response in metal sheets during percussion laser drilling. For this procedure the fourth-harmonic Nd:YAG wavelength (266 nm) was used in pulsed mode. The method provides a cost-efficient and robust alternative to speckle interferometry for the study of the small deformations that appear during laser processing. The accuracy was shown to be of the order of a few tens of microradians for the tilt component that is measured, which translates to a few nanometers in deflection when the component is spatially integrated. In the measurements, deflections in the form of craters as large as 50 nm were detected on the back sides of silver and copper sheets. The diameters of the craters were 300 microm in the silver and 150 microm in the copper sheet; the output diameter of the hole was -5 microm.