Compression and low velocity impact response of wood-based sandwich panels with auxetic lattice core

European Journal of Wood and Wood Products - The research determined the resistance to compression and low velocity impact of wood-based sandwich panels, the face sheet made of high-density fiber...     

Waterborne cationomer polyurethane coatings with improved hydrophobic properties

The AFM method was used to investigate the phase structure of the coatings, which have been obtained after application of polyurethane cationomers, synthesized in the reaction of 4,4′‐methylenebis(phenyl isocyanate) or isophorone diisocyanate with polyoxyethylene glycol (M = 600) and N‐methyl or N‐butyldiethanolamine with 2,2,3,3‐tetrafluoro‐1,4‐butanediol. Changes were discussed in the surface‐free energy (SFE) and its components, as calculated independently according to the method suggested by van Owens–Wendt, in relation to chemical structures of cationomers, as well as morphology of coating surfaces obtained from those cationomers. Fluorine incorporated into cationomers (about 2–5%) contributed to lower SFE values, down to about 30 mJ/m². An attempt was made to use ¹H‐NMR spectroscopy to provide more extensive grounds for the effect of polyurethane chemical structures (by parameters κ) on the SFE of coatings obtained from such polyurethanes, with the values of SFE (γ_S, γ) and determined by the Owens–Wendt method. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Hydrophobic and superhydrophobic surfaces fabricated by plasma polymerization of perfluorohexane,perfluoro(2-methylpent-2-ene), and perfluoro(4-methylpent-2-ene)

Fluoropolymer films were deposited on silicon (1 0 0) wafers, glass, epoxy, and hierarchical dual-sized filler epoxy composite surfaces by plasma polymerization of perfluorohexane, perfluoro(2-methylpent-2-ene), and perfluoro(4-methylpent-2-ene). The procedure involved continuous wave plasma-enhanced deposition, followed by a discharge-off period, with the monomer gas feed maintained. Silanization of silicon wafers and glass surfaces with triethoxyvinylsilane was employed to improve plasma fluoropolymer bonding to these substrates. The presence of double bonds in perfluoro(2-methylpent-2-ene) and perfluoro(4-methylpent-2-ene) was found to influence fluoropolymer coating topography, thereby increasing surface roughness in modified glass and epoxy substrates. All fluorocarbons provided a similar level of hydrophobization of flat substrates, exhibited by water contact angles (WCA) of about 110°. Hydrophobization of nanocomposite hierarchical surfaces by plasma polymerization provided superhydrophobic surfaces, with WCA of 160° and contact angle hysteresis below 8°.     

Approximation of Jacobian Inverse Kinematics Algorithms: Differential Geometric vs. Variational Approach

This paper addresses the approximation problem of Jacobian inverse kinematics algorithms for redundant robotic manipulators. Specifically, we focus on the approximation of the Jacobian pseudo inverse by the extended Jacobian algorithm. The algorithms are defined as certain dynamic systems driven by the task space error, and identified with vector field distributions. The distribution corresponding to the Jacobian pseudo inverse is non-integrable, while that associated with the extended Jacobian is integrable. Two methods of devising the approximating extended Jacobian algorithm are examined. The first method is referred to as differential geometric, and relies on the approximation of a non-integrable distribution (in fact: a codistribution) by an integrable one. As an alternative, the approximation problem has been formulated as the minimization of an approximation error functional, and solved using the methods of the calculus of variations. Performance of the obtained extended Jacobian inverse kinematics algorithms has been compared by means of computer simulations involving the kinematics model of the 7 dof industrial manipulator POLYCRANK. It is concluded that the differential geometric method offers a rapid, while the variational method a systematic tool for solving inverse kinematic problems.     

Partial breakage of a tunneled dialysis catheter: An uncommon finding

Infections and dysfunction are the most common complications related to catheter use. Here we describe a case of catheter rupture on the course of subcutaneous channel. Catheter fractures are relatively rare, but potentially hazardous complications. In case of partial breakage, a catheter exchange should be a simple solution.     

Products of Bisphenol A Degradation Induce Cytotoxicity in Human Erythrocytes (In Vitro)

The aim of this work has been to study the possible degradation path of BPA under the Fenton reaction, namely to determine the energetically favorable intermediate products and to compare the cytotoxicity of BPA and its intermediate products of degradation. The DFT calculations of the Gibbs free energy at M06-2X/6-311G(d,p) level of theory showed that the formation of hydroquinone was the most energetically favorable path in a water environment. To explore the cytotoxicity the erythrocytes were incubated with BPA and three intermediate products of its degradation, i.e., phenol, hydroquinone and 4-isopropylphenol, in the concentrations 5–200 μg/mL, for 1, 4 and 24 h. BPA induced the strongest hemolytic changes in erythrocytes, followed by hydroquinone, phenol and 4-isopropylphenol. In the presence of hydroquinone, the highest level of RONS was observed, whereas BPA had the weakest effect on RONS generation. In addition, hydroquinone decreased the level of GSH the most. Generally, our results suggest that a preferable BPA degradation path under a Fenton reaction should be controlled in order to avoid the formation of hydroquinone. This is applicable to the degradation of BPA during waste water treatment and during chemical degradation in sea water.     

Sensitive and Selective Voltammetric Sensor Based on Anionic Surfactant-Modified Screen-Printed Carbon for the Quantitative Analysis of an Anticancer Active Fused Azaisocytosine-Containing Congener

3-(4-Nitrophenyl)-8-(2,3-dimethylphenyl)-7,8-dihydroimidazo[2,1-c][1,2,4]triazin-4(6H)-one (NDIT) is one of the most promising candidates for anticancer agents. Hence, a sensitive and selective sodium dodecyl sulfate-modified screen-printed carbon sensor (SPCE/SDS) was used for its quantitative analysis. The SPCE/SDS, in contrast to the SPCE, showed excellent behavior in the electrochemical reduction of NDIT by differential-pulse adsorptive stripping voltammetry (DPAdSV). Cyclic voltammetric (CV) studies reveal an irreversible, two-stage and not purely diffusion-controlled reduction process in 0.01 M HNO₃. The sensor was characterized by CV and electrochemical impedance spectroscopy (EIS). Under the optimized conditions (t 45 s, ΔE 175 mV, ν 150 mV/s, and t_m 5 ms), the DPAdSV procedure with the SPCE/SDS presented a very wide linear range from 1 to 2000 nM and a low detection limit of 0.29 nM. A 1000-fold excess concentration of potential interferents commonly present in biological samples did not significantly alter the peak current of NDIT. The practical application of the proposed DPAdSV procedure with the SPCE/SDS was successfully checked by analyzing spiked human serum samples.     

Characterization of Antibodies against Receptor Activity-Modifying Protein 1 (RAMP1): A Cautionary Tale

Calcitonin gene-related peptide (CGRP) is a key component of migraine pathophysiology, yielding effective migraine therapeutics. CGRP receptors contain a core accessory protein subunit: receptor activity-modifying protein 1 (RAMP1). Understanding of RAMP1 expression is incomplete, partly due to the challenges in identifying specific and validated antibody tools. We profiled antibodies for immunodetection of RAMP1 using Western blotting, immunocytochemistry and immunohistochemistry, including using RAMP1 knockout mouse tissue. Most antibodies could detect RAMP1 in Western blotting and immunocytochemistry using transfected cells. Two antibodies (844, ab256575) could detect a RAMP1-like band in Western blots of rodent brain but not RAMP1 knockout mice. However, cross-reactivity with other proteins was evident for all antibodies. This cross-reactivity prevented clear conclusions about RAMP1 anatomical localization, as each antibody detected a distinct pattern of immunoreactivity in rodent brain. We cannot confidently attribute immunoreactivity produced by RAMP1 antibodies (including 844) to the presence of RAMP1 protein in immunohistochemical applications in brain tissue. RAMP1 expression in brain and other tissues therefore needs to be revisited using RAMP1 antibodies that have been comprehensively validated using multiple strategies to establish multiple lines of convincing evidence. As RAMP1 is important for other GPCR/ligand pairings, our results have broader significance beyond the CGRP field.     

RNA-Seq Analysis of UPM-Exposed Epithelium Co-Cultivated with Macrophages and Dendritic Cells in Obstructive Lung Diseases

Background. Elevated concentrations of airborne pollutants are correlated with an enlarged rate of obstructive lung disease morbidity as well as acute disease exacerbations. This study aimed to analyze the epithelium mRNA profile in response to airborne particulate matter in the control, asthma, and COPD groups. Results. A triple co-culture of nasal epithelium, monocyte-derived macrophages, and monocyte-derived dendritic cells obtained from the controls, asthma, and COPD were exposed to urban particulate matter (UPM) for 24 h. RNA-Seq analysis found differences in seven (CYP1B1, CYP1B1-AS1, NCF1, ME1, LINC02029, BPIFA2, EEF1A2), five (CYP1B1, ARC, ENPEP, RASD1, CYP1B1-AS1), and six (CYP1B1, CYP1B1-AS1, IRF4, ATP1B2, TIPARP, CCL22) differentially expressed genes between UPM exposed and unexposed triple co-cultured epithelium in the control, asthma, and COPD groups, respectively. PCR analysis showed that mRNA expression of BPIFA2 and ENPEP was upregulated in both asthma and COPD, while the expression of CYP1B1-AS1 and TIPARP was increased in the epithelium from COPD patients only. Biological processes changed in UPM exposed triple co-cultured epithelium were associated with epidermis development and epidermal cell differentiation in asthma and with response to toxic substances in COPD. Conclusions. The biochemical processes associated with pathophysiology of asthma and COPD impairs the airway epithelial response to UPM.     

Synthesis and Biological Evaluation of Thiazole-Based Derivatives with Potential against Breast Cancer and Antimicrobial Agents

Investigating novel, biologically-active coordination compounds that may be useful in the design of breast anticancer, antifungal, and antimicrobial agents is still the main challenge for chemists. In order to get closer to solving this problem, three new copper coordination compounds containing thiazole-based derivatives were synthesized. The structures of the synthesized compounds and their physicochemical characterization were evaluated based on elemental analysis, ¹H and ^l3C nuclear magnetic resonance (NMR), flame atomic absorption spectroscopy (F-AAS), single-crystal X-ray diffraction, thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR). The pharmacokinetics were studied using SwissADME. The results obtained from the computational studies supported the results obtained from the MTT analysis, and the antimicrobial activity was expressed as the minimum inhibitory concentration (MIC).