Angle Dependence of Photonic Enhancement of Magneto-Optical Kerr Effect in DMS Layers

We investigate theoretically an angle dependence of enhancement of polar magneto-optical Kerr effect (MOKE) obtained thanks to a deposition of a paramagnetic Diluted Magnetic Semiconductor (DMS) layer on one-dimensional photonic crystal layer. Our transfer matrix method based calculations conducted for TE and TM polarizations of the incident light predict up to an order of magnitude stronger MOKE for a (Ga,Fe)N DMS layer when implementing the proposed design. The maximum enhancement for TE and TM polarization occurs for the light incidence at the normal and at the Brewster angle, respectively. This indicates a possibility of tuning of the MOKE enhancement by adjustment of the polarization and the incidence angle of the light.Comment: 6 figure

Physicochemical interaction of antitumor acridinone derivatives with DNA in view of QSAR studies

The acridinone derivatives with antitumor activity and ability with respect to noncovalent DNA binding were investigated for their quantitative structure–activity relationships (QSAR). Multiple regression analysis was used to model relationships between molecular descriptors and antileukemia activity, or between molecular descriptors and DNA-duplexes stabilization. Studies were performed on molecular modeling using HyperChem and Dragon computer programs, and molecular geometry optimization using MM+ molecular mechanics and semi-empirical AM1 method. Two multiple regression equations were derived and characterized as good and with statistically significant correlations, R = 0.9384 and R = 0.8388, for quantitative structure–antitumor activity relationships and quantitative structure–ability to DNA-duplexes stabilization relationships, respectively. Moreover, hydrophobic and total molecular symmetry properties are important for antitumor activity of acridinone derivatives, and electronic and topological properties are important for physicochemical (noncovalent) DNA-duplexes stabilization of these compounds. The obtained equations can be used for prediction of acridinone derivatives’ activity and their ability to noncovalent interaction with DNA which, as it was shown earlier, play important role in the antitumor mechanism of action of these compounds

Piperazine derivatives as dangerous abused compounds

Piperazine derivatives are a group of compounds with a psychostimulant effect. They are an alternative to illegal drugs. They are being searched for recreational use due to their psychoactive and hallucinogenic effects. The high popularity of these compounds can be noticed all over the world due to easy purchase, lack of legal regulations and incorrect assessment of the safety of use. The recreational use of piperazine derivatives can often result in chronic and acute health problems and additionally with unpredictable remote effects. It is also common to take mixtures of psychoactive compounds. This hinders the correct diagnosis and treatment of patients with poisoning. The presented work is an illustration of the wide problem of piperazine derivatives abuse. The health effects and the possibility of identifying these compounds in preparations and biological material are described

Comparison of high -performance thin layer chromatography/UV-densitometry and UV-derivative spectrophotometry for determination of trimetazidine in pharmaceutical formulation

New methods for assaying trimetazidine dihydrochloride on the basis of thin layer chromatography and spectrophotometry are proposed and compared in the paper. In HPTLC/UV-densitometry, separation is achieved by using a mobile phase composed of ammonia-methanol (30:70, V/V) on silica gel HPTLC plates F254. Quantification using a non-linear calibration curve is accomplished by densitometric detection at 230 nm. Derivative spectrophotometric determination of trimetazidine dihydrochloride is carried out from the fourth derivative of the absorbance at 233 nm in peak-zero mode. Statistical comparison led to the conclusion that there is no significant difference between the two studied methods and, moreover, that they demonstrate satisfactory accuracy and precision for routine applications

Ability to determine the nontransferrin-bound iron and total iron in the human placenta using high-performance liquid chromatography method

Iron is one of the most important microelements in the human body. It is a component of haemoglobin, which transports oxygen to all cells in the organism. It is also used in the synthesis of myelin, neurotrans-mitters, and DNA and transfers electrons in biochemical reactions. Iron is also responsible for regular development of the foetus’ central nervous system. Furthermore, as a result of Fenton reactions, iron leads to formation of toxic free radicals. The existence of non-transferrin-bound iron (NTBI) and its part desfer-rioxamine-chelatable iron (DCI) can be used to assess this element in the body. The placenta is an organ transition that is formed during pregnancy in the female organism. It has a dense web of blood vessels in which dynamic exchange of blood between mother and foetus takes place. As a result, a fraction of NTBI may be present in the placenta. The main goal of this work was to develop a method for determining total iron and desferrioxamine-chelatable iron in solid tissues - the human placenta.Iron is one of the most important microelements in the human body. It is a component of hemoglobin which transports oxygen to all cells in the organism. It is also used in a synthesis of myelin, neurotransmitters and DNA, and transfers electrons in the biochemical reactions. Iron is also responsible for regular development of a fetus central nervous system. Furthermore, as a result of Fenton reactions, iron leads to formation of toxic free radicals. Existence of non-transferrin-bound iron (NTBI) and its part - desferrioxamine-chelatable iron (DCI) can be used for assess this element in a body. Placenta is an organ transition which is formed during pregnancy in a female organism. It has a dense web of blood vessels where dynamic exchange of blood between mother and fetus takes place. As a result, fraction of NTBI may be present in the placenta. The main goal of this work was to develop a method for determination of total iron and desferrioxamine-chelatable iron in solid tissues - a human placent

Long-term Absolute Wavelength Stability of Acetylene-stabilized Reference Laser at 1533 nm , Journal of Telecommunications and Information Technology, 2016, nr 4

The second harmonic generation process in Periodically Poled Lithium Niobate (PPLN) has been applied in order to measure frequency of reference laser locked to acetylene absorption peak 12 12 12C2 2 2H2 2 2 (P13) (1533 nm) against optical frequency synthesizer. The measurement results have been compared to the results obtained using different techniques for the same reference laser during the past 10 years in other laboratories

Ionic Liquids as Mobile Phase Additives for Feasible Assay of Naphazoline in Pharmaceutical Formulation by HPTLC–UV–Densitometric Method

A specific and reliable High-Performance Thin Layer Chromatography (HPTLC) with densitometry detection method has been developed for determination of naphazoline nitrate in nasal drops. The best separation of basic analyte, without spot tailing, was achieved using the mobile phase composed of acetonitrile:water (60:40,v/v) with 1.5 % (v/v) imidazolium-class ionic liquid added and the plates covered with stationary phase based on the RP-18 with F254S (10cm x 20cm). The presented results confirm that imidazolium tetrafluoroborate ionic liquids are efficient suppressors of free silanols, which are considered to be responsible for troublesome and irreproducible chromatographic determinations of basic compounds. The developed chromatographic system was found to be convenient in use and at the same time providing a repeatable assay of naphazoline nitrate in nasal drops, which could not be obtained with the use of standard silanol suppressing mobile phase additives, like triethylamine (TEA) or dimethyloctylamine (DMOA)

Serum amino acid profiling in differentiating clinical outcomes of multiple sclerosis

Aim of the study. Amino acid metabolism is crucial for regulating immune responses and can be monitored in blood serum samples. This study aimed to analyse serum amino acid profiles in people with multiple sclerosis (pwMS), taking into account differences depending on the disease outcomes. Clinical rationale for the study. Serum amino acid profiling is a promising, reproducible and minimally invasive technology, available at different stages of the disease, enabling the search for a specific biomarker to differentiate MS clinical outcomes. Material and methods. The serum concentrations of 29 amino acids were determined using high-performance liquid chromatography mass spectrometry. Results. A total of 121 pwMS (41 relapsing-remitting MS–RRMS; 55 secondary progressive MS - SPMS; and 25 primary progressive MS–RRMS) with a median Expanded Disability Status Scale (EDSS) score of 6 and 53 healthy controls (HCs) were included. We found significantly higher serum total amino acids concentrations in pwMS compared to HCs. Serum concentrations of arginine, 1-methyl-L-histidine and proline were higher in pwMS, while circulating citrulline, α-aminobutyric acid and tryptophan were lower in pwMS. We observed significant differences in serum total amino acids concentrations depending on MS type, with the highest level in the PPMS group and the lowest in the RRMS group. We found significantly higher serum levels of beta-aminoisobutyric acid in PPMS patients compared to those with RRMS and SPMS, and significantly higher serum levels of aspartic acid in PPMS patients compared to RRMS patients. From visual inspection, no trend was observed in total amino acids concentration with respect to the EDSS score. When analysing serum total amino acids concentration in pwMS with EDSS ≤ 5 compared to those with EDSS > 5, no significant differences were found. Conclusions and clinical implications. Amino acid metabolism is altered in pwMS and depends on the clinical type of the disease. Further studies are needed to determine whether serum metabolomic profiling of amino acids may have an application in the search for clinical phenotype-specific MS biomarkers