Hemodialysis‐induced changes in the blood composition affect function of the endothelium

Hemodialysis induces oxidative stress causing intravascular inflammation, which may cause endothelial dysfunction. We evaluated how hemodialysis‐induced changes in blood affect the function of endothelial cells in in vitro culture. Serum samples were collected from 42 uremic patients treated with hemodialysis, one before the start of dialysis and the other one at the end of session. All patients were dialysed with polysulfone dialyzer. Concentrations of the inflammatory molecules carbonyl protein and metabolites of NO synthesis were measured in blood. Additionally, the effect of the serum obtained before and after dialysis on the function of endothelial cells in in vitro culture was studied. Hemodialysis caused increase of monocyte chemoattractant protein (MCP)‐1 (+17%), hepatocyte growth factor (+91%), and pentraxin‐3 (+30%) concentration in serum. Concentration of carbonyl protein was decreased by 30%. Decrease of blood level of asymmetric dimethylarginine (?25%) and nitrate/nitrites (?62%) was observed. Serum obtained after hemodialysis stimulated proliferation of endothelial cells (+10%) and synthesis of MCP‐1(+11%) in these cells. Hemodialysis‐induced intravascular inflammation changes the function of endothelial cells, which may lead to acceleration of atherosclerosis.     

Physicochemical and catalytic properties of palladium deposited on polyaniline-coated silica gel

The chemical incorporation of palladium into polyaniline (PANI) deposited onto the silica gel microparticles (15-μm in diameter) was studied. The as-prepared silica particles coated with PANI–hydrochloride (AC) were treated with aqueous ammonia solution (0.1 M) to transform polyaniline to its base (BA) form. Both AC and BA samples were reacted with PdCl₂ solutions (2.3×10⁻³ M) strongly differing in the concentration of HCl (0.1 M HCl, series K; 6.6×10⁻⁴ M HCl, series Z). Two series of samples with 0.43–2.14 wt.% Pd were obtained. Fourier-transform infra red (FTIR), UV-Vis, X-ray photoelectron spectroscopies (XPS) and scanning electron microscopy have been used to examine the nature of processes involved upon insertion of Pd and to characterize palladium species in the final samples. Very similar palladium species were found in the polymer matrix independently of the acidity of PdCl₂ solutions and the extent of PANI protonation (AC and BA samples). Pd²⁺ was the only form if no more than 0.86% Pd was introduced. Incorporation of higher content of palladium resulted in the partial reduction (14.6–28.7%) of Pd²⁺ to Pd⁰. The presence of Pd²⁺ species in the form of complexes in which besides Cl⁻ ligands also nitrogen groups of PANI participated has been postulated. The catalytic properties of Pd/PANI-SiO₂ have been studied in the liquid-phase hydrogenation of 2-ethylanthraquinone (EAQ) at 60 °C under 1 atm of hydrogen. Very low activity of the as-prepared catalysts significantly increased due to reduction of the samples with NaH₂PO₂ and subsequently with dihydrogen. The specific activities of reduced series K and Z samples were comparable and the maximum activity exhibited catalysts with 1–1.5% Pd.     

Thermal stability of polyurethanes with carbon-carbon crosslinks

Thermal properties of polyurethanes based on 4,4′-diphenylmethane diisocyanate and poly(ethylene adipate) crosslinked only by C? C linkages were studied by isothermal and non-isothermal thermogravimetry carried out in nitrogen atmosphere. Previously studied polyurethanes crosslinked only with allophanate groups were used for comparison. It was found that the structure of crosslinks determines the initial stage of degradation process.     

Designing and assessing everyday objects: Impact of externalisation tools and judges’ backgrounds

Professional designers increasingly rely on IT-based systems in the course of their work. It is therefore crucial to know how such systems, especially computer-aided design (CAD) systems, influence both the design process and the final design, compared with the use of manual design methods. The objective of this paper is twofold: to address this issue and to suggest ways of improving IT-based systems specifically developed to support designers’ activities. In the first phase of a two-phase study, we investigated how the use of different tools can affect the design process. In the second phase, we conducted two complementary analyses to determine how the use of different tools affects the assessment of final designs, as well as the effect of the judges’ backgrounds on their assessments. We began by comparing the activities of two groups of designers: one group working with a CAD system, the other carrying out manual modelling. The results of this first phase revealed significant differences in the designers’ activities (changing the viewpoint, switching tools, correcting errors) according to the design method they used. We then asked judges from four different backgrounds (professional designers, design teachers, retailers and users), to assess the final designs according to specific assessment criteria (aesthetics, originality, functionality, marketability). The results of this second phase revealed a significant preference for objects designed with a CAD system. Furthermore, the judges attributed different levels of importance to each of the assessment criteria, depending on their background. This last result underscored differences in the mental models constructed by different groups of audiences involved in product development and marketing. In addition, it allowed us to identify their specific expectations about final designs. Based on the results of our analyses, we suggest ways of improving IT-based systems with a view to integrating design assessment more fully into CAD environments.     

Comparison of furanocoumarin concentrations of greenhouse-grownRuta chalepensis with outdoor plants later transferred to a greenhouse

Ruta chalepensis contained concentrations of furanocoumarins 25–50% of those found inR. graveolens both in the whole leaf and on its surface. On the leaf surface of plants grown all year indoors in a greenhouse, they increased steadily between November 1 and December 14 on mature upper and lower leaves. New growth upper leaves on December 14 contained less than mature upper leaves. Plants transferred from outdoors to the greenhouse showed decreased concentrations after the first two weeks, followed by recovery both in the whole leaf and on the leaf surface. Proportions of xanthotoxin and bergapten to psoralen changed during the experiment. On the leaf surfaces and in the whole upper leaves of the indoor plants, the proportions were often similar, but in the transferred plants, in most cases, psoralen was less than bergapten or xanthotoxin in the upper leaves and markedly less in the lower leaves. Implications of these findings for possible effects of environmental changes on secondary plant metabolism are discussed.     

Macrophage-Derived Adenosine Deaminase 2 Correlates with M2 Macrophage Phenotype in Triple Negative Breast Cancer

Several lines of evidence suggest that altered adenosine deaminase (ADA) activity, especially its ADA2 iso-enzyme, is associated with malignant breast cancer (BC) development. Triple-negative breast cancer (TNBC) is currently the most challenging BC subtype due to its metastatic potential and recurrence. Herein, we analyzed the sources of ADA iso-enzymes in TNBC by investigating the effects of cell-to-cell interactions between TNBC cells, macrophages, lymphocytes, and endothelial cells. We also examined the potential relationship between ADA activity and cancer progression in TNBC patients. In vitro analyses demonstrated that the interactions of immune and endothelial cells with MDA-MB-231 triple negative BC cells modulated their extracellular adenosine metabolism pattern. However, they caused an increase in the ADA1 activity, and did not alter ADA2 activity in cancer cells. In turn, the co-culture of MDA-MB-231 cells with THP-1 monocyte/macrophages, Jurkat cells, and human lung microvascular endothelial cells (HULEC) caused the increase in ADA2 activity on THP-1 cells and ADA1 activity on Jurkat cells and HULEC. Clinical sample analysis revealed that TNBC patients had higher plasma ADA2 activities and lower ADA1/ADA2 ratio at advanced stages of cancer development than in the initial stages, while patients with hormone receptor positive, HER2 negative (HR+HER2-), and triple positive (HR+HER2+) breast cancers at the same stages showed opposite trends. TNBC patients also demonstrated positive associations between plasma ADA2 activity and pro-tumor M2 macrophage markers, as well as between ADA1 activity and endothelial dysfunction or inflammatory parameters. The analysis of TNBC patients, at 6 and 12 months following cancer treatment, did not showed significant changes in plasma ADA activities and macrophage polarization markers, which may be the cause of their therapeutic failure. We conclude that alterations in both ADA iso-enzymes can play a role in breast cancer development and progression by the modulation of extracellular adenosine-dependent pathways. Additionally, the changes in ADA2 activity that may contribute to the differentiation of macrophages into unfavorable pro-tumor M2 phenotype deserve special attention in TNBC.     

Identification of Three Type II Toxin-Antitoxin Systems in Model Bacterial Plant Pathogen Dickeya dadantii 3937

Type II toxin-antitoxin (TA) systems are genetic elements usually encoding two proteins: a stable toxin and an antitoxin, which binds the toxin and neutralizes its toxic effect. The disturbance in the intracellular toxin and antitoxin ratio typically leads to inhibition of bacterial growth or bacterial cell death. Despite the fact that TA modules are widespread in bacteria and archaea, the biological role of these systems is ambiguous. Nevertheless, a number of studies suggests that the TA modules are engaged in such important processes as biofilm formation, stress response or virulence and maintenance of mobile genetic elements. The Dickeya dadantii 3937 strain serves as a model for pathogens causing the soft-rot disease in a wide range of angiosperm plants. Until now, several chromosome-encoded type II TA systems were identified in silico in the genome of this economically important bacterium, however so far only one of them was experimentally validated. In this study, we investigated three putative type II TA systems in D. dadantii 3937: ccdAB_2Dda, phd-doc_Dda and dhiTA, which represents a novel toxin/antitoxin superfamily. We provide an experimental proof for their functionality in vivo both in D. dadantii and Escherichia coli. Finally, we examined the prevalence of those systems across the Pectobacteriaceae family by a phylogenetic analysis.     

Key Properties of a Bioactive Ag-SiO2/TiO2 Coating on NiTi Shape Memory Alloy as Necessary at the Development of a New Class of Biomedical Materials

Recent years have seen the dynamic development of methods for functionalizing the surface of implants using biomaterials that can mimic the physical and mechanical nature of native tissue, prevent the formation of bacterial biofilm, promote osteoconduction, and have the ability to sustain cell proliferation. One of the concepts for achieving this goal, which is presented in this work, is to functionalize the surface of NiTi shape memory alloy by an atypical glass-like nanocomposite that consists of SiO₂-TiO₂ with silver nanoparticles. However, determining the potential medical uses of bio(nano)coating prepared in this way requires an analysis of its surface roughness, tribology, or wettability, especially in the context of the commonly used reference coat-forming hydroxyapatite (HAp). According to our results, the surface roughness ranged between (112 ± 3) nm (Ag-SiO₂)—(141 ± 5) nm (HAp), the water contact angle was in the range (74.8 ± 1.6)° (Ag-SiO₂)—(70.6 ± 1.2)° (HAp), while the surface free energy was in the range of 45.4 mJ/m² (Ag-SiO₂)—46.8 mJ/m² (HAp). The adhesive force and friction coefficient were determined to be 1.04 (Ag-SiO₂)—1.14 (HAp) and 0.247 ± 0.012 (Ag-SiO₂) and 0.397 ± 0.034 (HAp), respectively. The chemical data showed that the release of the metal, mainly Ni from the covered NiTi substrate or Ag from Ag-SiO₂ coating had a negligible effect. It was revealed that the NiTi alloy that was coated with Ag-SiO₂ did not favor the formation of E. coli or S. aureus biofilm compared to the HAp-coated alloy. Moreover, both approaches to surface functionalization indicated good viability of the normal human dermal fibroblast and osteoblast cells and confirmed the high osteoconductive features of the biomaterial. The similarities of both types of coat-forming materials indicate an excellent potential of the silver-silica composite as a new material for the functionalization of the surface of a biomaterial and the development of a new type of functionalized implants.     

New Frontiers in Electron Beam–Driven Chemistry in and around Graphene

Modern aberration corrected transmission electron microscopes offer the potential for electron beam sensitive materials, such as graphene, to be examined with low energy electrons to minimize, and even avoid, damage while still affording atomic resolution, and thus providing excellent characterization. Here in this review, the exploits in which the electron beam interactions, which are often considered negative, are explored to usefully drive a wealth of chemistry in and around graphene, importantly, with no other external stimuli. After introducing the technique, this review covers carbon phase reactions between amorphous carbon, graphene, fullerenes, carbon chains, and carbon nanotubes. It then explores different studies with clusters and nanoparticles, followed by coverage of single atom and molecule interactions with graphene, and finally concludes and highlights the anticipated exciting future for electron beam driving chemistry in and around graphene.