LC-MS/MS method validation for determination of selected neonicotinoids in groundwater for the purpose of a column experiment.

The work was carried out to develop and validate a method based on liquid chromatography tandem mass spectrometry (LC-MS/MS) for the simultaneous detection and quantification of five neonicotinoid insecticides: acetamiprid, clothianidin, imidacloprid, thiacloprid and thiamethoxam in groundwater samples for the purpose of a further column experiment. This experiment will be used to analyze breakthrough curves of neonicotinoids under a saturated water flow to set transport parameters, where the reliability of the results of chemical analysis plays an important role. The validation was performed in a concentration range from 0.09 µg L-1 to 100 µg L-1 using an Infinity 1290 (Agilent, USA) chromatograph coupled with a QTrap 5500 mass spectrometer (Sciex, Canada). The calibration curves were obtained on the basis of the results of six standard solution analyses. Linearity was not lower than 0.998. The limit of detection was set at the lowest concentration which can be determined with an acceptable accuracy and precision. All pesticides had recoveries in the range 85-109% with relative standard deviation values less than 8.1%. The estimated measurement uncertainty did not exceed 30%, so the LC-MS/MS method fits for the intended purpose.

Theoretical reproduction of the Q-band absorption spectrum of free-base chlorin.

The computational results of the features observed in the room-temperature Q-band absorption spectrum of free-base chlorin (H2Ch) are presented. The vibrational structures of the first and second excited singlet states were calculated based on a harmonic approximation using density functional theory and its time dependent extension within the Franck-Condon and Herzberg-Teller approaches. The outcome allowed to identify the experimental bands and to assign them to the specific vibrational transitions. A very good agreement between the simulated and measured wavelengths and their relative intensities provided the opportunity to predict the origin of the S0 → S2 transition which could not be determined experimentally.

Theoretical investigation of porphyrin-based photosensitizers with enhanced NIR absorption.

Porphyrins are compounds which are fundamental for designing many photosensitizers assigned for use in photodynamic therapy (PDT). However, photosensitizers available on the drug market are not ideal for use in PDT among others because of their low absorption in the wavelength range optimal for tissue penetration, i.e. the near-infrared (NIR) spectral region. In the present study the density functional theory and its time dependent extension calculations have been used to design new porphyrin-based photosensitizers with absorption in the therapeutic window of PDT of 700-800 nm. Theoretical investigation of four different derivatives of the 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin (p-THPP) revealed specific 'bridge' configurations which have a significant influence on absorption spectra. The results of the present study may be a useful starting point for future design of porphyrin derivatives as improved photosensitizers.

Neutrophil extracellular traps in upper respiratory tract secretions: insights into infectious and allergic rhinitis.

Introduction: Neutrophil extracellular traps (NETs) are structures released by neutrophils in response to various infections. NETs have a biocidal role and have been demonstrated to be effective against bacteria, fungi, viruses, and parasites. Depending on the situation, NETs can protect the host from pathogen invasion or contribute to the development of autoimmune diseases such as cystic fibrosis and rheumatoid arthritis. In this study, we aimed to investigate the occurrence of NET as one of the components in upper respiratory tract secretions in infectious and allergic diseases. Methods: Nasal mucus was collected from donors diagnosed with infectious rhinitis or allergic rhinitis. The extracellular DNA content was determined using SytoxGreen staining, and the total protein pool was determined using the microBCA method. Micrococcal nuclease was used to digest the samples and ELISA was employed to identify the NET proteins. The enzymatic activity of elastase was determined. Results: Our findings showed that nasal mucus collected from patients with infectious rhinosinusitis contained extracellular DNA that could come from a variety of sources, responsible for increasing the density and viscosity of secretions, as well as NETs proteins. The identified enzymatic activity of NET elastase indicates the possible irritation of nasal tissues. However, the DNA content was not identified in the samples from allergic patients. In addition, we have shown in preliminary studies that therapy using N-acetylcysteine can liquefy nasal secretions. Discussion: The study suggests that the composition of nasal mucus varies according to the cause of mucosal irritation. The presence of DNA and NET proteins can have severe consequences for the therapeutic process prolonging treatment. The low viscosity of nasal mucus in allergic patients facilitates mucosal flushing and the removal of allergens. Understanding the occurrence and role of NETs in various respiratory diseases is critical for developing effective treatment strategies that consider the complex interaction between the immune system and pathogens. The results of this study suggest that NETs may be present in upper respiratory tract secretions with an infectious background, supporting basic defense mechanisms using eosinophils and EETs. Further research is needed to explore the potential of NETs as a therapeutic target in respiratory diseases.

Phenotypic Variation of Autosomal Recessive Leber Hereditary Optic Neuropathy (arLHON) in One Family.

Leber hereditary optic neuropathy (LHON) is a rare disease with a prevalence of 1 in 25,000 births. LHON usually presents in young males, with painless loss of visual acuity in one or both eyes. Recently an autosomal recessive form of the disease (arLHON or LHONAR) has been described, which is caused by a biallelic mutation in the DNAJC30 gene (usually a missense mutation c.152A>G). The phenotypic and clinical characteristics of patients with arLHON are similar to those of mtLHON, but some differences have been described. Therapy is problematic and challenging. This paper describes clinical and electrophysiological findings in one family (three children and two parents) with arLHON and emphasizes the role of Photopic Negative Response Electroretinography, which provides objective measurement of retinal ganglion cells function. In Leber hereditary optic neuropathy, abnormal retinal ganglion cells function can be found in both eyes, even if visual acuity loss only occurs in one eye. Early clinical diagnosis, confirmed by genetic analysis, may be the key to sight-preserving treatment.

DFT/TD-DFT study of solvent effect as well the substituents influence on the different features of TPP derivatives for PDT application.

Spectral characteristics study of meso-tetraphenylporphyrin derivatives (TPP1 and TPP2) used as photosensitizers for utilization in photodynamic therapy (PDT) has been performed by density functional theory (DFT) and time dependent DFT (TD-DFT) calculations at B3LYP/6-31 G(d) level of theory using PCM solvation model. The geometrical parameters of porphyrins have been studied for ground and excited-state geometry to deduce the influence of various substituents as well as solvent effect on the deformation of porphyrin ring. Two theoretical approaches - linear response (LR) and external iteration (EI) - have been performed to replicate absorption and fluorescence emission spectra. Experimental and theoretical investigations have shown that EI method reproduces the absorption energies very well for both singlet-singlet and triplet-triplet transitions, whereas the LR approach is more coherent with experimental fluorescence emission spectra. Spectral features and HOMO-LUMO band gap analysis have shown that TPP1 can be more useful in PDT. Calculations have revealed that two the highest occupied and two the lowest unoccupied molecular orbitals are responsible for the Q-band absorption and are located mainly on the porphyrin ring. In order to verify the substituent effect on the activity of tested compounds in their ground and excited states, the molecular electrostatic potential surfaces have been analyzed.