On the Hilbert Evolution Algebras of a Graph

Evolution algebras are a special class of nonassociative algebras exhibiting connections with various fields of mathematics. Hilbert evolution algebras generalize the concept in the framework of Hilbert spaces. This allows us to deal with a wide class of infinite-dimensional spaces. We study Hilbert evolution algebras associated to a graph. Inspired by the definitions of evolution algebras we define the Hilbert evolution algebra that is associated to a given graph and the Hilbert evolution algebra that is associated to the symmetric random walk on a graph. For a given graph, we provide the conditions for these structures to be or not to be isomorphic. Our definitions and results extend to the graphs with infinitely many vertices. We also develop a similar theory for the evolution algebras associated to finite graphs.

     

Fairness in ambulance routing for post disaster management

Central European Journal of Operations Research - Disaster management generally includes the post-disaster stage, which consists of the actions taken in response to the disaster damages. These...     

Binding of an inhibitor of the p53/MDM2 interaction to MDM2

The mode of action of the secondary metabolite chlorofusin, which antagonises the interaction between p53 and MDM2, involves direct binding to the N-terminal domain of MDM2.     

Preparation and self-assembly of chiral porphyrin diads on the gold electrodes of quartz crystal microbalances: a novel potential approach to the development of enantioselective chemical sensors

Porphyrin diad 1 was synthesized by reaction of the acyl chloride of porphyrin 2 and trans-1,2-dithiane-4,5-diol. The Co complex of this diad was studied as a potential enantioselective receptor for chiral recognition in solution and in the solid state. In solution both enantiomers of limonene induce significant changes in the visible and circular dichroism (CD) spectra of [Co2(1)], while a different behavior is observed in the case of the enantiomeric pair of trans-1,2-diaminocyclohexane. A different efficiency of [Co2(1)] chiral recognition is obtained for these compounds, with a remarkable degree of enantiodiscrimination observed in the case of limonene. Self-assembled monolayers of [Co2(1)] were deposited onto the gold electrodes of quartz crystal microbalances to be used as sensing materials of nanogravimetric sensors operating in the gas phase. The enantiodiscrimination properties of these sensors towards the enantiomeric pairs of chiral analytes have been studied. While in the case of analytes bearing donor ligand atoms we did not observe a remarkable enantioselectivity, a significant degree of chiral discrimination was observed in the case of limonene; this result is particularly encouraging for the potential development of enantioselective chemical sensors for use in an array configuration.     

Gaucher disease-associated glucocerebrosidases show mutation-dependent chemical chaperoning profiles

Gaucher disease is a lysosomal storage disorder caused by deficient glucocerebrosidase activity. We have previously shown that the cellular activity of the most common Gaucher disease-associated glucocerebrosidase variant, N370S, is increased when patient-derived cells are cultured with the chemical chaperone N-nonyl-deoxynojirimycin. Chemical chaperones stabilize proteins against misfolding, enabling their trafficking from the endoplasmic reticulum. Herein, the generality of this therapeutic strategy is evaluated with other glucocerebrosidase variants and with additional candidate chemical chaperones. Improved chemical chaperones are identified for N370S glucocerebrosidase. Moreover, we demonstrate that G202R, a glucocerebrosidase variant that is known to be retained in the endoplasmic reticulum, is also amenable to chemical chaperoning. The L444P variant is not chaperoned by any of the active site-directed molecules tested, likely because this mutation destabilizes a domain distinct from the catalytic domain.     

Application of gas chromatography-tandem mass spectrometry to the analysis of pesticides in fruits and vegetables

A new analytical method was devised using gas chromatography with tandem mass spectrometry (GC-MS-MS) for the routine analysis of 31 multi-class pesticide residues and approximately 8000 fresh fruit and vegetable samples (green bean, cucumber, pepper, tomato, eggplant, watermelon, melon, and marrow). Extraction of the pesticides with dichloromethane was carried out. The optimal ionization mode, either electron impact or chemical ionization, was selected for each pesticide in the same run. Carbofrit was used in the liner and combined with the selectivity of the detector this avoided additional clean-up. Thus, not only was money and time saved, the uncertainty of the method was decreased in its application to routine analysis. The average recoveries in cucumber obtained for each pesticide ranged between 71 and 119% at two different fortification levels (n=10 each) that ranged between 7 and 300 ng g(-1) (depending on the pesticide). The relative standard deviation was lower than 19% for all compounds tested. The calculated limits of detection and quantification were typically <1 ng g(-1) which were much lower than the maximum residue levels established by European legislations.     

Flow injection analysis: Rayleigh light scattering technique for total protein determination

A novel flow injection analysis (FIA) method with Rayleigh light scattering (RLS) detection was developed for the determination of total protein concentrations. This method is based on the weak intensity of RLS of bromothymol blue (BB) (3',3"-dibromothymolsulfonephthalein) which can be enhanced by the addition of protein in weakly acidic solution. A common spectrofluorimeter was used as a detector. It was proved that the application of this method to quantify the total proteins in real samples by using bovine serum albumin was possible. The RLS signal was detected at lambda(ex)= lambda(em)=572 nm. The linear range was 7.0-70.0 microg mL(-1), the detection limit was 3.75 microg mL(-1), the reproducibility was 5.5% (n=7), and the sample throughput was 26 h(-1).     

A new ionic liquid dimethyldinonylammonium bromide as a flow modifier for the simultaneous determination of eight carboxylates by capillary electrophoresis

Two new methods of capillary zone electrophoresis based on aqueous phosphate running buffers with UV spectrophotometric detection were developed and optimized for the determination of eight carboxylates as copper complexes. Metalcomplexes are negatively charged, so measurements were made as anion analyses with flow reversal in the capillary. Two flow modifiers were used: a common tetradecyltrimethylammonium bromide (TTAB) and a new ionic liquid dimethyldinonylammonium bromide (DMDNAB). The methods were compared to each other. Better separation was achieved with DMDNAB as the flow modifier. Method development was done using a fused silica capillary (61 cm x 50 microm i.d.).Optimization was done using 95 mmol L(-1) phosphate buffer with TTAB or DMDNAB in the concentration 0.5 mmol L(-1) at pH 7.1. A -20 kV voltage and direct UV detection at 254 nm was used in measurements. In both CE methods all the peaks in the electropherograms were properly separated, the calibration plots gave good correlation coefficients and all eight carboxylates were detected in less than 7.5 min. The two methods were tested with natural water samples and a paper mill sample, and proved to be feasible.     

Selection of a Representative Matrix for Calibration in Multianalyte Determination of Pesticides in Vegetables by Liquid Chromatography-Electrospray Tandem Mass Spectrometry

An analytical method for determining residues of twenty pesticides by liquid chromatography (LC) coupled to electrospray ionisation (ESI) tandem mass spectrometry (MS-MS) in eight commodities, cucumber, tomato, pepper, green bean, eggplant, zucchini, melon and watermelon, has been developed and validated. On one hand, calibration curves prepared in solvent were compared with calibration curves prepared in a blank matrix extract of each target matrix. On the other hand, calibration curves and recoveries for each commodity were compared. Cucumber was selected as potential reference matrix for the target vegetables.