High-resolution capillary electrophoresis for the determination of carbamylated albumin

Objectives Carbamylation is a non-enzymatic post-translational reaction of a primary amino group of a protein with isocyanate. The albumin carbamylation is a negative prognostic factor in chronic kidney disease (CKD) patients and induce charge difference implying an observed shift in electrophoretic mobility that can be measured through a symmetry factor (SF). Methods The Helena V8 and the Sebia Capillarys 2 systems were used for all experiments. The effect of in vitro carbamylation on the SF by spiking increasing concentrations of potassium isocyanate (KCNO) in serum of three healthy volunteers was investigated. Theoretical plate numbers (N) as a surrogate of separation efficiency were also calculated and correlations between SF and renal function biomarkers were performed on 284 patients. Results A dose-dependent impact of KCNO on the SF was observed for both methods with the Helena V8 being more sensitive. The mean N was significantly higher on the Helena V8 as compared to the Sebia Capillarys 2 (2,972 vs. 444.1, p<0.0001). The SF correlated significantly with eGFR (r=0.50, p<0.0001), creatinine (r=−0.31, p<0.0001) and urea (r=−0.34, p<0.0001) on the Helena V8. On the Sebia Capillarys 2, a significant correlation was only observed with eGFR (r=0.17, p=0.004). A better discrimination between CKD stages was also observed using the Helena V8. Conclusions Thanks to a higher mean N, the Helena V8 might offer new possibilities, including detection of carbamylated albumin through SF calculation. Further studies are still needed to confirm the interest of using this type of assays in clinical routine.

Colourful Poincaré symmetry, gravity and particle actions

We construct a generalisation of the three-dimensional Poincaré algebra that also includes a colour symmetry factor. This algebra can be used to define coloured Poincaré gravity in three space-time dimensions as well as to study generalisations of massive and massless free particle models. We present various such generalised particle models that differ in which orbits of the coloured Poincaré symmetry are described. Our approach can be seen as a stepping stone towards the description of particles interacting with a non-abelian background field or as a starting point for a worldline formulation of an associated quantum field theory.

ANALYSIS OF THERMOLUMINESCENCE GLOW CURVES RECORDED UNDER THE HYPERBOLIC HEATING SCHEME BY USING AN ALTERNATIVE CONCEPT OF SYMMETRY

Usually, the order of kinetics of thermoluminescence (TL) glow curve is evaluated by using the concept of traditional symmetry factor (μ_g) in which only three points of a glow curve are used. From the statistical point of view of the reliability of any method of analysis of glow, curve improves if instead of a few points the method can use a larger portion of the glow curve. In the present work, a technique is proposed to determine the order of kinetics associated with a TL peak by using the concept of skewness. The method is applied to experimental thermoluminescence (TL) curves recorded in a hyperbolic heating scheme.

MO460ASSOCIATION BETWEEN CARBAMYLATED ALBUMIN, GUT MICROBIOTA AND THEIR DERIVED METABOLITES IN CHRONIC KIDNEY DISEASE

Background and Aims Chronic kidney disease (CKD) is characterized by gut dysbiosis. We recently demonstrated a decrease of short-chain fatty acid (SCFA) producing bacterial species with the progression of CKD. Besides, levels of protein-bound uremic toxins (PBUTs) and post-translational modifications of protein are increased in CKD, both are risk factors for accelerated cardiovascular morbidity and mortality. The link between the gut-kidney axis and protein carbamylation is unclear. The aim of the study was to explore the relation between carbamylated albumin, estimated by the albumin symmetry factor, and plasma levels of PBUTs, fecal levels of SCFAs (ongoing), and the abundance of related gut microbiota in different stages of CKD (1-5). Method The study cohort includes 103 non-dialyzed CKD patients (stages 1-5). Serum proteins were detected by capillary electrophoresis and UV absorbance at 214 nm with the symmetry factor as a marker of albumin carbamylation [the lower the symmetry factor, the more carbamylated albumin]. The quantification of PBUTs and SCFAs in plasma and fecal samples, respectively, using validated UPLC methods. Results The Pearson correlation coefficient (r) shows a positive correlation between the albumin symmetry factor and the estimated glomerular filtration rate (eGFR) (r=0.3025; p=0.0019). The albumin symmetry factor correlates positively with the abundance of Butyricicoccus spp. (r= 0.3211; p=0.0009), Faecalibacterium prausnitzii (r=0.2765; p=0.0047) and Roseburia spp. (r=0.2527; p=0.0100) and negatively with the PBUTs, p-cresyl sulfate (pCS) (r=-0.2819; p=0.0039), p-cresyl glucuronide (pCG) (r=-0.2819; p=0.0039) and indoxyl sulfate (IxS) (r=-0.2650; p=0.0068). Conclusion The decreased abundance of SCFA producing gut bacteria with the progression of CKD can evoke unfavorable conditions in the gut. This can contribute to increased plasma levels of PBUTs potentially (indirectly) playing a role in albumin carbamylation. It will be further explored whether fecal levels of SCFAs are affected in parallel and could be potential targets to restore gut dysbiosis and uremia.

Symmetry factors of Feynman diagrams and the homological perturbation lemma

We discuss the symmetry factors of Feynman diagrams of scalar field theories with polynomial potential. After giving a concise general formula for them, we present an elementary and direct proof that when computing scattering amplitudes using the homological perturbation lemma, each contributing Feynman diagram is indeed included with the correct symmetry factor.

MODELS OF RANDOM SYSTEMS WITH CONTROLLED SYMMETRY IN STREAM ENCRYPTION

Information safety plays an important role in modern technologies. A stream encryption is one of the common means for information safety support. The sequences with pseudo-random characteristics are often required in the algorithms of stream enciphering. Random systems are recently used as a source of pseudo-random numbers with desired statistical properties. A small length of a sequence period is one of the known problems of the generators of pseudo-random numbers based on chaos realized with a small length of a digit grid. The disturbance of a path or a parameter of random system nonlinearity is one of possible solutions of a short period problem. In this paper there is considered a new approach to the increase of a period length through the change of a symmetry factor in the random model of a memristive circuit. The approach offered is based on switching two values of the symmetry factor in accordance with the output of a shear register with the linear feedback. To confirm the effectiveness of the disturbance circuit described the lengths of a period for the disturbed and original model of the memristive system are estimated. The properties of the output sequences caused by a generator on the basis of the model with controlled symmetry are confirmed by the results of the correlation analysis and NIST statistical testing. The results obtained can be used in cryptographic applications and also at the designing of safe communication systems.

An Overview on Peak Shape Method for Thermoluminescence Glow Curve Analysis

The shape of a thermoluminescence (TL) glow curve has fundamental importance for calculating the characteristic parameters of trap levels within the band gap. TL analysis are mostly based on the three-parameter general order kinetics model. The parameters are activation energy, order of kinetics, and frequency factor. Peak shape method is one of the most prominent methods for extracting the activation energy from a TL curve. An overview of different peak shape methods along with an alternative approach formulated directly from basic TL equations is presented in this chapter. Generally, peak shape method requires prior knowledge of order of kinetics to determine activation energy which creates a difficulty due to the non-uniqueness of symmetry factor for a particular value of order of kinetics. A modified version of peak shape method which is free from this constraint is discussed here. Activation energies from experimental curves of tremolite and actinolite are estimated using peak shape method. Limitation of peak shape method for saturated TL peaks with heavy retrapping is also discussed.