Relationship between Aldose reductase and superoxide dismutase inhibition capacities of indole-based analogs of melatonin derivatives

Aldose reductase (AR) has been implicated in the etiology of diabetic complications. Under diabetic conditions, the elevated vascular glucose level causes an increased flux through the polyol pathway, which induces functional and morphological changes associated with secondary diabetic complications such as cataract, neuropathy, and nephrop­athy. Oxidative stress, antioxidants, and the polyol pathway have recently been found to be linked in pathological states. A large number of structurally different compounds have been studied as potent in vitro AR inhibitors (ARIs). However, with few exceptions, these compounds did not show clinical benefit, and some even produced serious side effects. In view of the ARI activity of certain indole derivative compounds and antioxidant properties of melatonin, we investigated some indole-based analogs of melatonin derivatives. Antioxidant and ARI activity tests were applied to nine indole derivatives that are substituted at the third and fifth positions. Also, the relationship between ARI and antioxidant enzyme activity is discussed

Determining Remaining Lifetime of Wind Turbine Gearbox Using a Health Status Indicator Signal

Wind turbine component's failure prognosis allows wind farm owners to apply predictive maintenance techniques to their fleets. This permits optimal scheduling of the maintenance actions considering the best time to stop the turbines and perform those actions. Determining the health status of a turbine's component typically requires verifying a wide number of variables that should be monitored simultaneously. The scope of this study is the investigation and the selection of an effective combination of variables and smoothing and forecasting methodologies for obtaining a wind turbine gearbox health status indicator, in order to interpret clearly the remaining lifetime of the gearbox. The proposed methodology is based on Gaussian Mixture Copula Model (GMCM) models combined with the smoothing treatment and the forecasting model to define the health index of the wind turbine gearbox. Then, the resulting index is tested using various warning and critical thresholds. These thresholds should be chosen adequately in order to indicate appropriate inspection visit and preventive maintenance intervention date. Then, the best combination found, for the studied cases, was 50% and 70% for warning and critical respectively. This combination ensures that the developed procedure is capable of providing long enough time window for maintenance decision making

Exo-hydrogenated Single Wall Carbon Nanotubes

An extensive first-principles study of fully exo-hydrogenated zigzag (n,0) and armchair (n,n) single wall carbon nanotubes (C$_n$H$_n$), polyhedral molecules including cubane, dodecahedrane, and C$_{60}$H$_{60}$ points to crucial differences in the electronic and atomic structures relevant to hydrogen storage and device applications. C$_n$H$_n$'s are estimated to be stable up to the radius of a (8,8) nanotube, with binding energies proportional to 1/R. Attaching a single hydrogen to any nanotube is always exothermic. Hydrogenation of zigzag nanotubes is found to be more likely than armchair nanotubes with similar radius. Our findings may have important implications for selective functionalization and finding a way of separating similar radius nanotubes from each other.Comment: 5 pages, 4 postscript figures, Revtex file, To be appear in Physical Review

Simple sequence repeat (SSR) analysis for assessment of genetic variability in wild cherry germplasm

Conservation of genetic resources is vital for future breeding programs and food security for humans. Before conservation of genetic resources, it requires objective characterization and a proper assignation of individual genotypes to species. The aim of this study was to characterize of 58 Prunus accessions which belong to Prunus avium, Prunus cerasus and Prunus mahaleb by using 12 SSR markers. All twelve SSR markers produced successful amplifi cations and revealed DNA polymorphisms. The number of allele per loci varied from 6 (UDP96-019) to 12 (PS12A02) with an average of 9 per allele. The average of observed and expected heterozygosity was found to be 0.609 and 0.720. The allele size varied from 95 to 276 bp. The number of genotypes per allele were 7 (UCD-CH13) and 24 (UDP96-005). Genetic distance analysis based on SSRs divided the cherry accessions in three main groups based mainly on their species characteristics. P. cerasus genotypes had higher similarity ratio within species than P. mahaleb and P. avium

A Recombinant PvpA Protein-Based Diagnostic Prototype for Rapid Screening of Chicken Mycoplasma gallisepticum infections

Cataloged from PDF version of article.Mycoplasma gallisepticum is the primary agent of chronic respiratory disease causing important economic losses in the poultry industry. Serological monitoring is essential to maintain mycoplasma-free breeder flocks and often complicated by the cross-reactions between different mycoplasma species. To overcome serological cross-reactions, a large fragment of the M. gallisepticum PvpA cytadhesin, species-specific surface-exposed protein, was produced in E. coli as a recombinant protein (rPvpA336) and used as a potential diagnostic antigen. The rPvpA336 protein possesses 336 mycoplasma-specific amino acids with relative molecular weight of 44 kDa. A deletion region of 37 amino acids was identified when compared to the wild-type PvpA protein. Immunoreactivity of the rPvpA336 protein has been demonstrated by Western blot analysis with M. gallisepticum-positive and -negative chicken sera. Furthermore, an enzymatic rapid immunofiltration assay (ERIFA) prototype based on the rPvpA336 protein has been developed and its species-specific detection capability has been demonstrated by using M. gallisepticum and/or M. synoviae-positive and -negative chicken sera. In addition to its species-specificity, the ERIFA prototype presents certain advantages such as rapidity, field-applicability and cost-effectiveness. Therefore, these advantages would make the prototype a species-specific rapid diagnostic tool of choice in the field and limited laboratory conditions for screening M. gallisepticum infections. © 2007 Elsevier B.V. All rights reserved

Application of lactococcin BZ and enterocin KP against Listeria monocytogenes in milk as biopreservation agents

This study was performed to evaluate the effect of lactococcin BZ and enterocin KP against Listeria monocytogenes ATCC 7644 in skim (0.1%), half (1.5%), and full fat (3.0%) UHT milks. The milk samples were inoculated with L. monocytogenes at the level of approximately 2.60, 4.76, and 6.45 log CFU ml−1, and then treated with various concentrations (400, 800, 1600, or 2500 AU ml−1) of lactococcin BZ, enterocin KP, or their combination (1:1). Lactococcin BZ at 400–2500 AU ml−1 level displayed strong antilisterial activity, and decreased the viable cell numbers of L. monocytogenes to an undetectable level in all types of milk samples during the entire storage periods at 4 °C or 20 °C. Enterocin KP also had a high antilisterial effect, but it decreased as both the fat content of milk and inoculation amount of L. monocytogenes increased

Superconductivity in hole-doped C60 from electronic correlations

We derive a model for the highest occupied molecular orbital band of a C60 crystal which includes on-site electron-electron interactions. The form of the interactions are based on the icosahedral symmetry of the C60 molecule together with a perturbative treatment of an isolated C60 molecule. Using this model we do a mean-field calculation in two dimensions on the [100] surface of the crystal. Due to the multi-band nature we find that electron-electron interactions can have a profound effect on the density of states as a function of doping. The doping dependence of the transition temperature can then be qualitatively different from that expected from simple BCS theory based on the density of states from band structure calculations

Boolean Models of Bistable Biological Systems

This paper presents an algorithm for approximating certain types of dynamical systems given by a system of ordinary delay differential equations by a Boolean network model. Often Boolean models are much simpler to understand than complex differential equations models. The motivation for this work comes from mathematical systems biology. While Boolean mechanisms do not provide information about exact concentration rates or time scales, they are often sufficient to capture steady states and other key dynamics. Due to their intuitive nature, such models are very appealing to researchers in the life sciences. This paper is focused on dynamical systems that exhibit bistability and are desc ribedby delay equations. It is shown that if a certain motif including a feedback loop is present in the wiring diagram of the system, the Boolean model captures the bistability of molecular switches. The method is appl ied to two examples from biology, the lac operon and the phage lambda lysis/lysogeny switch