Assessment of the interaction procedure between Pt(IV) prodrug [Pt(5,5′-dmbpy)Cl4 and human serum albumin: Combination of spectroscopic and molecular modeling technique

In this study, a cytotoxic Pt(IV) complex [Pt(5,5′-dmbpy)Cl₄ (5,5′-dmbpy is 5,5′-dimethyl-2,2′-bipyridine) was selected to investigate its affinity to human serum albumin (HSA) by spectroscopy and molecular docking methods. This complex has a bidentate nitrogen donor ligand with four chloride anions attached to a Pt(IV) metal in a distorted octahedral environment. The ?uorescence data showed this complex quench the intrinsic ?uorescence of HSA through a static quenching mechanism. The binding constant (K_b) and the number of binding sites (n) were obtained based on the results of fluorescence measurements. UV–vis, circular dichroism spectroscopy, and three-dimensional fluorescence spectroscopy proved that the Pt(IV) complex could slightly change the secondary structure of protein. Thermodynamic parameters show that the Pt(IV) complex binds to HSA through electrostatic and Vander Waals interactions with one binding site. The molecular docking results confirmed the spectroscopic results and showed that Pt(IV) complex is embedded into subdomain IIA of protein. The aim of this study is to describe the performance of effective anti-cancer drugs when faced with proteins such as HSA.     

Optimizing MRI sequences and images for MRI-based stereotactic radiosurgery treatment planning

AimDevelopment of MRI sequences and processing methods for the production of images appropriate for direct use in stereotactic radiosurgery (SRS) treatment planning.BackgroundMRI is useful in SRS treatment planning, especially for patients with brain lesions or anatomical targets that are poorly distinguished by CT, but its use requires further refinement. This methodology seeks to optimize MRI sequences to generate distortion-free and clinically relevant MR images for MRI-only SRS treatment planning.Materials and methodsWe used commercially available SRS MRI-guided radiotherapy phantoms and eight patients to optimize sequences for patient imaging. Workflow involved the choice of correct MRI sequence(s), optimization of the sequence parameters, evaluation of image quality (artifact free and clinically relevant), measurement of geometrical distortion, and evaluation of the accuracy of our offline correction algorithm.ResultsCT images showed a maximum deviation of 1.3 mm and minimum deviation of 0.4 mm from true fiducial position for SRS coordinate definition. Interestingly, uncorrected MR images showed maximum deviation of 1.2 mm and minimum of 0.4 mm, comparable to CT images used for SRS coordinate definition. After geometrical correction, we observed a maximum deviation of 1.1 mm and minimum deviation of only 0.3 mm.ConclusionOur optimized MRI pulse sequences and image correction technique show promising results; MR images produced under these conditions are appropriate for direct use in SRS treatment planning.     

Electron‐Beam‐Evaporated Nickel Oxide Hole Transport Layers for Perovskite‐Based Photovoltaics

High‐quality charge carrier transport materials are of key importance for stable and efficient perovskite‐based photovoltaics. This work reports on electron‐beam‐evaporated nickel oxide (NiO_x) layers, resulting in stable power conversion efficiencies (PCEs) of up to 18.5% when integrated into solar cells employing inkjet‐printed perovskite absorbers. By adding oxygen as a process gas and optimizing the layer thickness, transparent and efficient NiO_x hole transport layers (HTLs) are fabricated, exhibiting an average absorptance of only 1%. The versatility of the material is demonstrated for different absorber compositions and deposition techniques. As another highlight of this work, all‐evaporated perovskite solar cells employing an inorganic NiO_x HTL are presented, achieving stable PCEs of up to 15.4%. Along with good PCEs, devices with electron‐beam‐evaporated NiO_x show improved stability under realistic operating conditions with negligible degradation after 40 h of maximum power point tracking at 75 °C. Additionally, a strong improvement in device stability under ultraviolet radiation is found if compared to conventional perovskite solar cell architectures employing other metal oxide charge transport layers (e.g., titanium dioxide). Finally, an all‐evaporated perovskite solar mini‐module with a NiO_x HTL is presented, reaching a PCE of 12.4% on an active device area of 2.3 cm².     

Molecular phylogeny of the subterranean genus Niphargus (Crustacea: Amphipoda) in the Middle East: a comparison with European Niphargids

The subterranean genus Niphargus is one of the most species‐rich genera among freshwater amphipods in the world, distributed in the Western Palearctic. Thus far, taxonomic and phylogenetic research has focused mainly on the European half of the genus range. In this study, 25 populations of Niphargus from Iran, Lebanon and the Crimean Peninsula were investigated. Bayesian inference based on 28S, H3 and COI gene sequences suggests that populations from the area belong to four different clades. Three species from Crimea and one species from Iran are nested at basal nodes, indicating their rather ancient origin. The rest of the species are younger and belong to two separate clades. One Crimean species is a sister‐species to east Romanian species. The second clade includes one species from Lebanon and all but one population from Iran. The origin of this clade corresponds to marine transgression between the Black Sea and Mediterranean approximately 12 Mya. This clade was further investigated taxonomically. Revision of qualitative morphological traits and unilocus species delimitation methods using COI suggest that this clade comprises 12–16 species, of which only three have been described so far. Multilocus coalescence delimitation methods (using fragments of COI, 28S, H3 and ITS) strongly supported 11 of these species. The remaining populations comprise at least two species complexes that require further and more detailed taxonomic research. © 2015 The Linnean Society of London     

Flower ontogeny in Capparis spinosa (Capparaceae) with special emphasis on symmetry expression

The flower ontogeny of Capparis spinosa L. was studied using scanning electron microscopy (SEM) in order to shed light on the early expression of symmetry in a representative member of Capparaceae. Sepals start decussately with the abaxial and adaxial sepals, followed by the lateral ones. Petal appearance proceeds uni‐directionally from the abaxial to the adaxial side. Stamens develop centrifugally on an androecial ring. Five to seven carpel lobes arise on a gynoecial ring. Monosymmetry is established in early development by the uni‐directional petal appearance and is further enhanced by the acquisition of an abaxial nectary appendage and differential development of perianth organs at anthesis. The early monosymmetric pattern found in C. spinosa differs from the early monosymmetric and early disymmetric pathways of Cleomoideae. Our findings are consistent with the hypothesis that the late establishment of monosymmetry is a reflective of symmetry in early development.     

Prevalence of Non-Tuberculosis Mycobacterial Infections among Tuberculosis Suspects in Iran: Systematic Review and Meta-Analysis

Introduction

The infections due to Non-Tuberculosis Mycobacteria (NTM) are becoming an important health problem in many countries in the world. Globally, an increase in NTM infections has been reported from many countries around the world. However, limited information is available about the prevalence of NTM infections in Iran.

Material and Methods

The data of the prevalence of NTM infections were collected from databases such as PubMed, Web of science, Cochrane Library, Embase, Scopus, Iranmedex, and Scientific Information Database. Comprehensive Meta-Analysis (V2.0, Biostat) software was used to analyze the data.

Results

The meta-analyses showed that the prevalence of NTM infections was 10.2% (95% confidence interval [95% CI] 6.3-15.9) among culture-positive cases of tuberculosis (TB) in Iran. The further stratified analyses indicated that the prevalence of NTM was higher in studies that were done after year 2000. Additionally, M. simiae (43.3% [95% CI 36.8-50.0]), M. intracellucar (27.3% [95% CI 0.7-95.5]) and M. fortuitum (22.7% [95% CI 16.1-30.9]) were the most prevalent NTM species, respectively.

Discussion

The relatively high prevalence of NTM infections (10.2%) among culture positive cases for TB underlines the need for greater enforcement of infection control strategies. Establishment of appropriate diagnostic criteria and management guidelines for NTM diseases and expanding the number and quality of regional reference laboratories may facilitate more accurate action for prevention and control of NTM infections in Iran.     

The stereoselective metabolism of halofantrine to desbutylhalofantrine in the rat: evidence of tissue-specific enantioselectivity in microsomal metabolism

The pharmacokinetics of the antimalarial drug (+/-)-halofantrine are stereoselective in humans and rats. To better understand the stereoselective metabolism of the drug to its primary metabolite, desbutylhalofantrine (DHF), a series of in vitro and in vivo experiments were undertaken in the rat. Formation of (-)-DHF exceeded that of (+)-DHF in liver microsomes [(-):(+) ratio of intrinsic formation clearances = 1.4]. In contrast, in intestinal microsomes no significant stereoselectivity was noted in the formation of the DHF enantiomers. Intestinal microsomes were also less efficient at producing the DHF enantiomers than were liver microsomes. Based on kinetic analysis of the DHF formation, there appeared to be more than one enzyme involved in the biotransformation. (+/-)-Ketoconazole (KTZ) effectively inhibited the formation of both DHF enantiomers by both liver and intestinal microsomes, although the reduction was more marked in liver microsomes. Through a combination of the use of CYP antibodies and recombinant CYP isoenzymes, the involvement of CYP 2B1/2, 3A1, 3A2, 1A1, 2C11, 2C6, 2D1, and 2D2 were implicated in the metabolism of halofantrine to DHF. Of these, CYP3A1/2 and CYP2C11 appeared to be the primary isoenzymes involved, although CYP2C11 showed greater (+)-DHF than (-)-DHF formation, whereas for CYP3A1 it was similar to the isolated rat liver microsomes. In vivo, oral (+/-)-KTZ caused significant increases in plasma halofantrine and decreases in DHF enantiomer plasma concentrations.     

Effect of Cation Composition on the Mechanical Stability of Perovskite Solar Cells

Photoactive perovskite semiconductors are highly tunable, with numerous inorganic and organic cations readily incorporated to modify optoelectronic properties. However, despite the importance of device reliability and long service lifetimes, the effects of various cations on the mechanical properties of perovskites are largely overlooked. In this study, the cohesion energy of perovskites containing various cation combinations of methylammonium, formamidinium, cesium, butylammonium, and 5‐aminovaleric acid is reported. A trade‐off is observed between the mechanical integrity and the efficiency of perovskite devices. High efficiency devices exhibit decreased cohesion, which is attributed to reduced grain sizes with the inclusion of additional cations and PbI₂ additives. Microindentation hardness testing is performed to estimate the fracture toughness of single‐crystal perovskite, and the results indicated perovskites are inherently fragile, even in the absence of grain boundaries and defects. The devices found to have the highest fracture energies are perovskites infiltrated into a porous TiO₂/ZrO₂/C triple layer, which provide extrinsic reinforcement and shielding for enhanced mechanical and chemical stability.     

Evaluation of the Role of Probiotics As a New Strategy to Eliminate Microbial Toxins: a Review

Probiotics and Antimicrobial Proteins - Probiotics are living microorganisms that have favorable effects on human and animal health. The most usual types of microorganisms recruited as probiotics...