Arylene bisimides with triarylamine N-substituents as new solution processable organic semiconductors: Synthesis,spectroscopic, electrochemical and electronic properties

New solution processable organic semiconductors, consisting of pyrromelitic, naphthalene or perylene bisimide core and triarylamine N-substituents, have been synthesized. All three compounds are electrochemically active and undergo quasi-reversible oxidation and reduction as evidenced by cyclic voltammetry investigations. The oxidation process involves the transformation of the triarylamine substituents into radical cations as proven spectroscopically and spectroelectrochemically. The reduction process occurs at the arylene bisimide core leading to the formation of a radical anion and eventually a dianion in the second step. These findings are in perfect agreement with the DFT calculations which show that in the synthesized molecules the HOMO orbital is located on the triarylamine moiety whereas the LUMO one on the bisimide core. In all molecules studied the electrochemically determined ionization potential (IP) is slightly higher than 5.0 eV whereas in naphthalene and perylene derivatives the electron affinity (EA) is close to ?3.9 eV. These values fulfill the requirements for n-type (electron) semiconductors in air operating n-channel field effect transistors (FETs) as well as for p-type (hole) conductors in p-channel FETs. To verify whether the newly synthesized compounds exhibit the expected electrical transport properties all organic (CYTOP dielectric) test transistors were fabricated. All three semiconductors showed no field effect in the n-channel configuration. To the contrary, they could be used in p-channel FETs showing, in the saturation regime, the hole mobility approaching 10^?4 cm² V^?1 s^?1 – the value which slightly exceeds that measured for low molecular weight, amorphous triarylamine semiconductors.     

The development of the tongue of the domestic goose from 9th to 25th day of incubation as seen by scanning electron microscopy

The general development of the tongue in birds was described by Lillie ( 1908 ) in chicken. Bryk et al. ( 1992 ) also studied the tongue development in chicken and they observed development of the conical papillae of the body. Our study aims to describe the timing of the development of the tongue morphological features in the domestic goose by using SEM methods. The tongue of the domestic goose is characterized by the widest variety of shape of the particular part of the tongue and mechanical papillae. Results indicated that the formation of the apex, body, lingual prominence, and the root of the tongue take place between the 10th and 19th day of incubation. The tongue elongates rapidly between the 16th and 18th day of incubation. Simultaneously, the median groove appears on the body and the lingual prominence and elongates towards the rostral part of the tongue. The conical papillae of the tongue develop gradually. On the body, the conical papillae develop from the caudal part of the body to the rostral part and on the lingual prominence from the median part of the prominence to the lateral part. Hair‐like papillae at the caudal surface of the body of the tongue remain primordial to the end of the incubation. Our studies on the morphogenesis of the tongue in the domestic goose revealed changes in shape of the particular part of the tongue and rapid pace of the formation of mechanical papillae. The tongue is completely develop before hatching and ready to collect food. © Microsc. Res. Tech., 2012. © 2012 Wiley Periodicals, Inc.     

CTLA-4 Expression Is a Promising Biomarker of Idiopathic Pulmonary Arterial Hypertension and Allows Differentiation of the Type of Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is an increasingly frequently diagnosed disease, the molecular mechanisms of which have not been thoroughly investigated. The aim of our study was to investigate subpopulations of lymphocytes to better understand their role in the molecular pathomechanisms of various types of PAH and to find a suitable biomarker that could be useful in the differential diagnosis of PAH. Using flow cytometry, we measured the frequencies of lymphocyte subpopulations CD4+CTLA-4+, CD8+ CTLA-4+ and CD19+ CTLA-4+ in patients with different types of PAH, namely pulmonary arterial hypertension associated with congenital heart disease (CHD-PAH), pulmonary arterial hypertension associated with connective tissue disorders (CTD-PAH), chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary arterial hypertension (iPAH), and in an age- and sex-matched control group in relation to selected clinical parameters. Patients in the iPAH group had the significantly highest percentage of CD4+CTLA-4+ T lymphocytes among all PAH groups, as compared to those in the control group (p < 0.001), patients with CTEPH (p < 0.001), CTD-PAH (p < 0.001) and CHD-PAH (p < 0.01). In iPAH patients, the percentages of CD4+CTLA-4+ T cells correlated strongly positively with the severity of heart failure New York Heart Association (NYHA) Functional Classification (r = 0.7077, p < 0.001). Moreover, the percentage of B CD19+CTLA-4+ cells strongly positively correlated with the concentration of NT-proBNP (r = 0.8498, p < 0.001). We have shown that statistically significantly higher percentages of CD4+CTLA-4+ (p ≤ 0.01) and CD8+ CTLA-4+ (p ≤ 0.001) T cells, measured at the time of iPAH diagnosis, were found in patients who died within 5 years of the diagnosis, which allows us to consider both of the above lymphocyte subpopulations as a negative prognostic/predictive factor in iPAH. CTLA-4 may be a promising biomarker of noninvasive detection of iPAH, but its role in planning the treatment strategy of PAH remains unclear. Further studies on T and B lymphocyte subsets are needed in different types of PAH to ascertain the relationships that exist between them and the disease.     

Acute Kidney Injury in COVID-19

COVID-19 is mainly considered a respiratory illness, but since SARS-CoV-2 uses the angiotensin converting enzyme 2 receptor (ACE2) to enter human cells, the kidney is also a target of the viral infection. Acute kidney injury (AKI) is the most alarming condition in COVID-19 patients. Recent studies have confirmed the direct entry of SARS-CoV-2 into the renal cells, namely podocytes and proximal tubular cells, but this is not the only pathomechanism of kidney damage. Hypovolemia, cytokine storm and collapsing glomerulopathy also play an important role. An increasing number of papers suggest a strong association between AKI development and higher mortality in COVID-19 patients, hence our interest in the matter. Although knowledge about the role of kidneys in SARS-CoV-2 infection is changing dynamically and is yet to be fully investigated, we present an insight into the possible pathomechanisms of AKI in COVID-19, its clinical features, risk factors, impact on hospitalization and possible ways for its management via renal replacement therapy.     

Palm Oil-Rich Diet Affects Murine Liver Proteome and S-Palmitoylome

Palmitic acid (C16:0) is the most abundant saturated fatty acid in animals serving as a substrate in synthesis and β-oxidation of other lipids, and in the modification of proteins called palmitoylation. The influence of dietary palmitic acid on protein S-palmitoylation remains largely unknown. In this study we performed high-throughput proteomic analyses of a membrane-enriched fraction of murine liver to examine the influence of a palm oil-rich diet (HPD) on S-palmitoylation of proteins. HPD feeding for 4 weeks led to an accumulation of C16:0 and C18:1 fatty acids in livers which disappeared after 12-week feeding, in contrast to an accumulation of C16:0 in peritoneal macrophages. Parallel proteomic studies revealed that HPD feeding induced a sequence of changes of the level and/or S-palmitoylation of diverse liver proteins involved in fatty acid, cholesterol and amino acid metabolism, hemostasis, and neutrophil degranulation. The HPD diet did not lead to liver damage, however, it caused progressing obesity, hypercholesterolemia and hyperglycemia. We conclude that the relatively mild negative impact of such diet on liver functioning can be attributed to a lower bioavailability of palm oil-derived C16:0 vs. that of C18:1 and the efficiency of mechanisms preventing liver injury, possibly including dynamic protein S-palmitoylation.     

Genetic Variability in DNA Repair Proteins in Age-Related Macular Degeneration

The pathogenesis of age-related macular degeneration (AMD) is complex and involves interactions between environmental and genetic factors, with oxidative stress playing an important role inducing damage in biomolecules, including DNA. Therefore, genetic variability in the components of DNA repair systems may influence the ability of the cell to cope with oxidative stress and in this way contribute to the pathogenesis of AMD. However, few reports have been published on this subject so far. We demonstrated that the c.977C>G polymorphism (rs1052133) in the hOGG1 gene and the c.972G>C polymorphism (rs3219489) in the MUTYH gene, the products of which play important roles in the repair of oxidatively damaged DNA, might be associated with the risk of AMD. Oxidative stress may promote misincorporation of uracil into DNA, where it is targeted by several DNA glycosylases. We observed that the g.4235T>C (rs2337395) and c.–32A>G (rs3087404) polymorphisms in two genes encoding such glycosylases, UNG and SMUG1, respectively, could be associated with the occurrence of AMD. Polymorphisms in some other DNA repair genes, including XPD (ERCC2), XRCC1 and ERCC6 (CSB) have also been reported to be associated with AMD. These data confirm the importance of the cellular reaction to DNA damage, and this may be influenced by variability in DNA repair genes, in AMD pathogenesis.     

Chrysin,Apigenin and Acacetin Inhibit Tumor Necrosis Factor-Related Apoptosis—Inducing Ligand Receptor-1 (TRAIL-R1) on Activated RAW264.7 Macrophages

Expression level of Tumor Necrosis Factor—related apoptosis—inducing ligand (TRAIL) receptors is one of the most important factors of TRAIL-mediated apoptosis in cancer cells. We here report for the first time data concerning TRAIL-R1 and TRAIL-R2 receptor expression on RAW264.7 macrophages. Three substances belonging to flavones: chrysin, apigenin and acacetin which differ from their substituents at the 4'' position in the phenyl ring were used in assays because of the variety of biological activities (e.g., anticancer activity) of the polyphenol compounds. The expression of TRAIL-R1 and TRAIL-R2 death receptors on non-stimulated and LPS (lipopolysaccharide)-stimulated macrophages was determined using flow cytometry. We demonstrate that RAW264.7 macrophages exhibit TRAIL-R1 surface expression and that the tested compounds: chrysin, apigenin and acacetin can inhibit TRAIL-R1 death receptor expression level on macrophages.     

Photolithographic patterning of organic photodetectors with a non-fluorinated photoresist system

We report on the fabrication of organic photodetectors (OPD) based on isolated islands of P3HT:PCBM. Pattern transfer to the active material was done with photolithography based on non-fluorinated solvents and the excessive organic semiconductor was removed with oxygen plasma reactive ion etching. The photoresist system used was found to be benign to the P3HT:PCBM layer as confirmed by absorption, thickness and roughness measurements. Current–voltage characteristics and external quantum efficiency (EQE) remained unchanged after the patterning process. It was demonstrated that it is possible to photolithographically pattern isolated islands with 200 μm edge length with the same dark current density (<10⁻⁵ A/cm² at −2 V bias voltage) and photocurrent density (>5 × 10⁻³ A/cm² at −2 V). Furthermore, concerning the solar cell performance, the patterned, small-area devices showed power conversion efficiency of 2.1% and fill-factor of 60%. Dark current was observed to depend on the size of the remaining semiconductor island, which was demonstrated on OPDs with diameter of 50 μm. The presented results show the feasibility of fabrication of isolated devices based on organic semiconductors patterned with non-fluorinated photolithography.     

Examining the Impact of Squaric Acid as a Crosslinking Agent on the Properties of Chitosan-Based Films

Hydrogels based on chitosan are very versatile materials which can be used for tissue engineering as well as in controlled drug delivery systems. One of the methods for obtaining a chitosan-based hydrogel is crosslinking by applying different components. The objective of the present study was to obtain a series of new crosslinked chitosan-based films by means of solvent casting method. Squaric acid—3,4-dihydroxy-3-cyclobutene-1,2-dione—was used as a safe crosslinking agent. The effect of the squaric acid on the structural, mechanical, thermal, and swelling properties of the formed films was determined. It was established that the addition of the squaric acid significantly improved Young’s modulus, tensile strength, and thermal stability of the obtained materials. Moreover, it should be stressed that the samples consisting of chitosan and squaric acid were characterized by a higher swelling than pure chitosan. The detailed characterization proved that squaric acid could be used as a new effective crosslinking agent.