Anodic Oxidation of Both Particulate and Compact Iron in Chloride-Containing Acetate Buffer Electrolytes

The voltammetric records of Fe powder and compact iron electrode in chloride-free and chloride-containing acetate buffer electrolytes of various pH values were compared in the range 4.0 to 6.0. Owing to the consumption of the powder, the voltammetric current at the powder electrode decreases nearly to zero. Full passivation of the iron surface was observed in the absence of chloride on both electrodes. The differences become clear in chloride-containing electrolytes: with the compact electrode, the dissolution proceeds continuously while with the powder electrode the rate of the process is limited by both the degree of iron conversion and potential applied. Chloride ions not only incorporate into the intermediate species but also form soluble species in the passivation layer, leading to its degradation. The result is an observable anodic dissolution reaction of further Fe powder. The composition of the layer differs in dependence on pH. At lower pH, dissolution proceeds faster and to a larger extent. At higher pH, the thickness of the passive layer is larger and it contains more Fe hydroxides/oxides with higher resistance to the action of chloride. Scanning electron microscopy confirmed deep breakdown of the crystal structure of Fe grains.     

Industrial architecture and negativity: the aesthetics of architecture in the works of Gordon Matta-Clark,Robert Smithson and Bernd and Hilla Becher

The modernist idea of monumentality derived its inspiration from the imagery of late-nineteenth century industrial structures. In the 1960s, this monumentality and modernist 'total design' was criticised by Robert Venturi and Denise Scott-Brown who proposed the 'ugly and ordinary' architecture and 'vital mess' of commercial populism instead. On the background of these two approaches, I will read the art works of Gordon-Matta Clark, Robert Smithson and Bernd and Hilla Bechers as giving voice to all that is forgotten, excluded or unacknowledged in architecture. The importance of these artists lies in their exploration of negativity in architecture. Their art works stage the contras, first, between the inevitable continuity of architecture as a process and its discontinuity when it is reduced to a set of objects, as well as the contrast, secondly, between the continuity of urban and architectural space and its discontinuity when our perceptions reduce it to its monumental and important parts. Negativity stands for the time 'before' and 'after' of what is commonly understood as an architecture, as well as for the 'invisible' materiality parts of urban space and buildings that are usually ignored. Today, it is in obsolete industrial architecture that negativity finds its purest expression: in the words of Walter Benjamin, the Modernists' imaginary monuments are recognised as ruins even before they have physically crumbled.     

Foliate-Targeting Quantum Dots-β-Cyclodextrin Nanocarrier for Efficient Delivery of Unsymmetrical Bisacridines to Lung and Prostate Cancer Cells

Targeted drug delivery by nanocarriers molecules can increase the efficiency of cancer treatment. One of the targeting ligands is folic acid (FA), which has a high affinity for the folic acid receptors, which are overexpressed in many cancers. Herein, we describe the preparation of the nanoconjugates containing quantum dots (QDs) and β-cyclodextrin (β-CD) with foliate-targeting properties for the delivery of anticancer compound C-2028. C-2028 was bound to the nanoconjugate via an inclusion complex with β-CD. The effect of using FA in QDs-β-CD(C-2028)-FA nanoconjugates on cytotoxicity, cellular uptake, and the mechanism of internalization in cancer (H460, Du-145, and LNCaP) and normal (MRC-5 and PNT1A) cells was investigated. The QDs-β-CD(C-2028)-FA were characterized using DLS (dynamic light scattering), ZP (zeta potential), quartz crystal microbalance with dissipation (QCM-D), and UV-vis spectroscopy. The conjugation of C-2028 with non-toxic QDs or QDs-β-CD-FA did not change the cytotoxicity of this compound. Confocal microscopy studies proved that the use of FA in nanoconjugates significantly increased the amount of delivered compound, especially to cancer cells. QD_green-β-CD(C-2028)-FA enters the cells through multiple endocytosis pathways in different levels, depending on the cell line. To conclude, the use of FA is a good self-navigating molecule in the QDs platform for drug delivery to cancer cells.     

tert‐Butylcarbamate‐Containing Histone Deacetylase Inhibitors: Apoptosis Induction,Cytodifferentiation, and Antiproliferative Activities in Cancer Cells

Herein we report novel pyrrole‐ and benzene‐based hydroxamates ( 8 , 10 ) and 2′‐aminoanilides ( 9 , 11 ) bearing the tert‐butylcarbamate group at the CAP moiety as histone deacetylase (HDAC) inhibitors. Compounds 8 b and 10 c selectively inhibited HDAC6 at the nanomolar level, whereas the other hydroxamates effected an increase in acetyl‐α‐tubulin levels in human acute myeloid leukemia U937 cells. In the same cell line, compounds 8 b and 10 c elicited 18.4 and 21.4 % apoptosis, respectively (SAHA: 16.9 %), and the pyrrole anilide 9 c displayed the highest cytodifferentiating effect (90.9 %). In tests against a wide range of various cancer cell lines to determine its antiproliferative effects, compound 10 c exhibited growth inhibition from sub‐micromolar (neuroblastoma LAN‐5 and SH‐SY5Y cells, chronic myeloid leukemia K562 cells) to low‐micromolar (lung H1299 and A549, colon HCT116 and HT29 cancer cells) concentrations. In HT29 cells, 10 c increased histone H3 acetylation, and decreased the colony‐forming potential of the cancer cells by up to 60 %.     

Microstructure of methyl methacrylate/tert-butyl acrylate copolymer characterized by 13C NMR spectroscopy

100 MHz ¹³C NMR spectra of methyl methacrylate/tert-butyl acrylate copolymer, PMMA/tBA, reveal configurational effects of both comonomers. The microstructure of the macromolecular chain has been determined utilizing carbonyl and β-CH₂ carbon signals and the spectral assignments were performed in terms of the configurational–compositional sequences. To determine the line positions of individual sequences, the incremental method of the chemical shift calculation has been applied. Based on these data, the analyzed signals were simulated yielding fairly good agreement with the experimental spectra—at the pentad level for the carbonyl signal and at the tetrad level for β-CH₂ signal.     

4-Hydroxynonenal Modulates Blood–Brain Barrier Permeability In Vitro through Changes in Lipid Composition and Oxidative Status of Endothelial Cells and Astrocytes

Blood brain barrier (BBB) is a dynamic interface responsible for proper functioning of brain, but also a major obstacle for effective treatment of neurological diseases. Increased levels of free radicals, in high ferrous and high lipid content surrounding, induce lipid peroxidation, leading to production of 4-hydroxynonenal (HNE). HNE modifies all key proteins responsible for proper brain functioning thus playing a major role in the onset of neurological diseases. To investigate HNE effects on BBB permeability, we developed two in vitro BBB models–‘physiological’ and ‘pathological’. The latter mimicked HNE modified extracellular matrix under oxidative stress conditions in brain pathologies. We showed that exogenous HNE induce activation of antioxidative defense systems by increasing catalase activity and glutathione content as well as reducing lipid peroxide levels in endothelial cells and astrocytes of ‘physiological’ model. While in ‘pathological’ model, exogenous HNE further increased lipid peroxidation levels of endothelial cells and astrocytes, followed by increase in Nrf2 and glutathione levels in endothelial cells. At lipid composition level, HNE caused increase in ω3 polyunsaturated fatty acid (PUFA) level in endothelial cells, followed by decrease in ω3 PUFA level and increase in monounsaturated fatty acid level in astrocytes. Using these models, we showed for the first time that HNE in ‘pathological’ model can reduce BBB permeability.     

Germinal vesicle position and meiotic maturation in mouse oocyte

During meiotic maturation, mammalian oocytes undergo an asymmetric division which is crucial for the formation of a functional gamete. In various organisms, accurate positioning of the nucleus before M-phase plays a major role in asymmetric cell divisions. However, the role of the position of the nucleus (or germinal vesicle, GV) during the prophase I arrest has not been investigated in mammalian oocytes. Here, we show that incompetent mouse oocytes possess a peripheral GV, while competent oocytes mainly exhibit a central position of the GV. At that time, the position of the GV correlates with the ability of the oocyte to complete meiotic maturation. Moreover, a lower efficiency in GV centering and a reduced ability to progress through meiosis are observed in oocytes from old mice. Thus, the position of the GV could be used as a simple morphological marker of oocyte quality.