Nickel(II)-catalysed oxidative guanine and DNA damage beyond 8-oxoguanine

Oxidative DNA damage is one of the most important and most studied mechanisms of disease. It has been associated with a range of terminal diseases such as cancer, heart disease, hepatitis, and HIV, as well as with a variety of everyday ailments. There are various mechanisms by which this type of DNA damage can be initiated, through radiation and chemical oxidation, among others; however, these mechanisms have yet to be fully elucidated. A HPLC-UV-EC study of the oxidation of DNA mediated by nickel(II) obtained results that show an erratic, almost oscillatory formation of 8-oxoguanine (8-oxoG) from free guanine and from guanine in DNA. Sporadic 8-oxoG concentrations were also observed when 8-oxoG alone was subjected to these conditions. A HPLC-MS/MS study showed the formation of oxidised-guanidinohydantoin (oxGH) from free guanine at pH 11, and the formation of guanidinohydantoin (GH) from DNA at pH 5.5

Modelling crystal aggregation and deposition\ud in the catheterised lower urinary tract

Urethral catheters often become encrusted with crystals of magnesium struvite and calcium phosphate. The encrustation can block the catheter, which can cause urine retention in the bladder and reflux into the kidneys. We develop a mathematical model to investigate crystal deposition on the catheter surface, modelling the bladder as a reservoir of fluid and the urethral catheter as a rigid channel. At a constant rate, fluid containing crystal particles of unit size enters the reservoir, and flows from the reservoir through the channel and out of the system. The crystal particles aggregate, which we model using Becker–Döring coagulation theory, and are advected through the channel, where they continue to aggregate and are deposited on the channel’s walls. Inhibitor particles also enter the reservoir, and can bind to the crystals, preventing further aggregation and deposition. The crystal concentrations are spatially homogeneous in the reservoir, whereas the channel concentrations vary spatially as a result of advection, diffusion and deposition. We investigate the effect of inhibitor particles on the amount of deposition. For all parameter values, we find that crystals deposit along the full length of the channel, with maximum deposition close to the channel’s entrance

High (but Not Low) Urinary Iodine Excretion Is Predicted by Iodine Excretion Levels from Five Years Ago

Background: It has not been investigated whether there are associations between urinary iodine (UI) excretion measurements some years apart, nor whether such an association remains after adjustment for nutritional habits. The aim of the present study was to investigate the relation between iodine-creatinine ratio (ICR) at two measuring points 5 years apart. Methods: Data from 2,659 individuals from the Study of Health in Pomerania were analyzed. Analysis of covariance and Poisson regressions were used to associate baseline with follow-up ICR. Results: Baseline ICR was associated with follow-up ICR. Particularly, baseline ICR >300 mu g/g was related to an ICR >300 mu g/g at follow-up (relative risk, RR: 2.20; p < 0.001). The association was stronger in males (RR: 2.64; p < 0.001) than in females (RR: 1.64; p = 0.007). In contrast, baseline ICR <100 mu g/g was only associated with an ICR <100 mu g/g at follow-up in males when considering unadjusted ICR. Conclusions: We detected only a weak correlation with respect to low ICR. Studies assessing iodine status in a population should take into account that an individual with a low UI excretion in one measurement is not necessarily permanently iodine deficient. On the other hand, current high ICR could have been predicted by high ICR 5 years ago. Copyright (C) 2011 S. Karger AG, Base

A study to analyze and develop design criteria for a flight-concept prototype vapor diffusion water reclamation unit Final report, Apr. 1967 - Apr. 1968

Design criteria and mathematical model for vapor diffusion water reclamation uni

Media Optimization, Strain Compatibility, and Low-Shear Modeled Microgravity Exposure of Synthetic Microbial Communities for Urine Nitrification in Regenerative Life-Support Systems

Urine is a major waste product of human metabolism and contains essential macro- and micronutrients to produce edible microorganisms and crops. Its biological conversion into a stable form can be obtained through urea hydrolysis, subsequent nitrification, and organics removal, to recover a nitrate-enriched stream, free of oxygen demand. In this study, the utilization of a microbial community for urine nitrification was optimized with the focus for space application. To assess the role of selected parameters that can impact ureolysis in urine, the activity of six ureolytic heterotrophs (Acidovorax delafieldii, Comamonas testosteroni, Cupriavidus necator, Delftia acidovorans, Pseudomonas fluorescens, and Vibrio campbellii) was tested at different salinities, urea, and amino acid concentrations. The interaction of the ureolytic heterotrophs with a nitrifying consortium (Nitrosomonas europaea ATCC 19718 and Nitrobacter winogradskyi ATCC 25931) was also tested. Lastly, microgravity was simulated in a clinostat utilizing hardware for in-flight experiments with active microbial cultures. The results indicate salt inhibition of the ureolysis at 30 mS cm(-1), while amino acid nitrogen inhibits ureolysis in a strain-dependent manner. The combination of the nitrifiers with C. necator and V. campbellii resulted in a complete halt of the urea hydrolysis process, while in the case of A. delafieldii incomplete nitrification was observed, and nitrite was not oxidized further to nitrate. Nitrate production was confirmed in all the other communities; however, the other heterotrophic strains most likely induced oxygen competition in the test setup, and nitrite accumulation was observed. Samples exposed to low-shear modeled microgravity through clinorotation behaved similarly to the static controls. Overall, nitrate production from urea was successfully demonstrated with synthetic microbial communities under terrestrial and simulated space gravity conditions, corroborating the application of this process in space

Correction Of Iodine Deficiency States And Dynamic Modeling Of Positive Dynamics Of Indicators Of Thyroid Functions By Supplementation

The problem of iodine deficiency diseases (IDD) is recognized as relevant due to the significant prevalence of iodine deficiency among the population of many countries of the world, an increase in the incidence of diseases with a wide range of clinical manifestations and a marked tendency to increase the frequency and severity of IDD among children of all age groupsWe carried out a clinical-anamnestic examination of the child\u27s contingent (187 persons) aged 13–17 years living in an ecologically dependent biogeochemical endemic zone of iodine deficiency, the mountain region of the Zakarpattya region during the period from 2014 to 2015. To identify the pathology of the thyroid gland, a palpatory method of examination was used according to the methodology of the WHO / MRKIDZ, 2001. According to our data 80 pupils (42.8 %) had increased thyroid gland of 1 degree, they were allocated for further and detailed examination and identification of environmentally caused somatic effects. Preventive measures included taking the dietary supplement Yosen, the manufacturer of TOV “OmniFarm”, TU U 10.8-35758392-004: 2014 for 6 months. A statistical model for forecasting the dynamics of TSH with supplements with iodine and selenium has been developed. According to our data, the degree of positive changes (decrease of TSH, increase of T4) with supplements with iodine and selenium depends on the starting content of the microelement of iodine in plasma and / or urine: the lower is the initial level of iodine - the more pronounced is the effect of supplements

A simple derivation of BV bounds for inhomogeneous relaxation systems

We consider relaxation systems of transport equations with heterogeneous source terms and with boundary conditions, which limits are scalar conservation laws. Classical bounds fail in this context and in particular BV estimates. They are the most standard and simplest way to prove compactness and convergence. We provide a novel and simple method to obtain partial BV regularity and strong compactness in this framework. The standard notion of entropy is not convenient either and we also indicate another, but closely related, notion. We give two examples motivated by renal flows which consist of 2 by 2 and 3 by 3 relaxation systems with 2-velocities but the method is more general

Report from the 5th international symposium on mycotoxins and toxigenic moulds : challenges and perspectives (MYTOX) held in Ghent, Belgium, May 2016

The association research platform MYTOX “Mycotoxins and Toxigenic Moulds” held the 5th meeting of its International Symposium in Ghent, Belgium on 11 May 2016.[...