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We present an observational study of the luminous red nova (LRN) AT\,2021biy in the nearby galaxy NGC\,4631. The field of the object was routinely imaged during the pre-eruptive stage by synoptic surveys, but the transient was detected only at a few epochs from $\sim 231$\,days before maximum brightness. The LRN outburst was monitored with unprecedented cadence both photometrically and spectroscopically. AT\,2021biy shows a short-duration blue peak, with a bolometric luminosity of $\sim 1.6 \times 10^{41}$\,erg\,s$^{-1}$, followed by the longest plateau among LRNe to date, with a duration of 210\,days. A late-time hump in the light curve was also observed, possibly produced by a shell-shell collision. AT\,2021biy exhibits the typical spectral evolution of LRNe. Early-time spectra are characterised by a blue continuum and prominent H emission lines. Then, the continuum becomes redder, resembling that of a K-type star with a forest of metal absorption lines during the plateau phase. Finally, late-time spectra show a very red continuum ($T_{\mathrm{BB}} \approx 2050$ K) with molecular features (e.g., TiO) resembling those of M-type stars. Spectropolarimetric analysis indicates that AT\,2021biy has local dust properties similar to those of V838\,Mon in the Milky Way Galaxy. Inspection of archival {\it Hubble Space Telescope} data taken on 2003 August 3 reveals a $\sim 20$\,\msun\ progenitor candidate with log\,$(L/{\rm L}_{\odot}) = 5.0$\,dex and $T_{\rm{eff}} = 5900$\,K at solar metallicity. The above luminosity and colour match those of a luminous yellow supergiant. Most likely, this source is a close binary, with a 17--24\,\msun\ primary component.

The strong piezoelectricity in diphenylalanine peptide develops its technological potential as a smart material. To achieve insight into the vertical alignment of size-controlled self-assembled diphenylalanine peptide nanotubes, an aromatic peptide of diphenylalanine (FF) was applied in this research as the model peptide. Here we found for the first time a vertical alignment of size-controlled self-assembled diphenylalanine peptide nanotubes during the peptide self-assembly process of nanotubes composite using polyethersulfone (PES) membrane in situ and ex situ peregnation of peptide nano tube. The membrane structure was investigated using fluofenamic acid as a fluorescent tag and a first-line solution containing dipeptides and hexafluoropropane (HFP). The results showed a vertical alignment of size-controlled self-assembled diphenylalanine peptide nanotubes formation on silicon. The STM and SEM results indicated the formation of different nanostructures including short nanorods, nanotubes branched nanotubes and dendritic nanostructures of peptide in PES membrane. Our novel approach based on the PES membrane and HFP allows one to controllably fabricate various peptide-based nanostructures on silicon.

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A novel polyethersulfone (PES) ultrafiltration membrane containing 0.05–2.00 wt% of synthesized mesoporous carbon nanoparticles (MCNs) was prepared via the phase inversion technique. The structures and properties of MCNs were characterized using a variety of analytic techniques. The MCNs showed the surface area of 1396.8 m2/g and the highest pore size of around 1 nm. The effect of incorporation of MCNs on the composite membrane morphology and performance was investigated through pure water flux, protein adsorption, and bacterial adhesion resistance tests. The membrane's anti-fouling performances were determined under constant-pressure operation at 100 kPa in a dead-end module. The as-prepared nanocomposite membranes were also studied in terms of morphology, structure and surface chemistry. Generally, the incorporation of MCNs into the polymeric membrane improved the pure water flux. The composite membrane containing 0.20 wt% MCNs exhibited the highest antifouling, protein adsorption resistance, and bacterial attachment inhibition property. The incorporation of the MCNs into the membranes introduces a different strategy of inhibiting biomolecule adsorption and bacterial attachment to the membrane surface, instead of killing the bacteria which may lead to more severe membrane fouling by the intracellular substances.

© 2016 Wiley Periodicals, Inc. In the field of total joint replacements, polymer nanocomposites are being investigated as alternatives to ultrahigh molecular weight polyethylene (UHMWPE) for acetabular cup bearings. The objective of this study was to investigate the wear performance and biocompatibility of UHMWPE/graphene oxide (GO) nanocomposites. This study revealed that low concentrations of GO nanoparticles (0.5 wt %) do not significantly alter the wear performance of UHMWPE. In contrast, the addition of higher concentrations (2 wt %) led to a significant reduction in wear. In terms of biocompatibility, UHMWPE/GO wear particles did not show any adverse effects on L929 fibroblast and PBMNC viability at any of the concentrations tested over time. Moreover, the addition of GO to a UHMWPE matrix did not significantly affect the inflammatory response to wear particles. Further work is required to optimize the manufacturing processes to improve the mechanical properties of the nanocomposites and additional biocompatibility testing should be performed to understand the potential clinical application of these materials. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 183–190, 2018.

Advanced surface modification approaches of biomaterials alongside the advent of sophisticated analytical techniques have provided a great opportunity to understand how the physicochemical characteristics of materials determine cell–surface dynamics at molecular and atomic scale. However, there are still many contradictory reports, which are mainly due to inadequate information about the role of the two parameters of surface chemistry and structure and their synergistic effect as an adequate predictor of biological performance. Here, surface parameters were altered by grafting of poly ethylene glycol (PEG) on polyurethane (PU) surfaces through a superhydrophilic modification method. In this study, surface modification of PU films by PEG thin layer via grafting technique and TiO2 nanoparticle entrapment in the brush polymers was investigated. The surface modification led to a reduction in protein adsorption and bacterial attachment by 8.7 times and 71% respectively with no cytotoxicity effect on HeLa cells. It was also observed that when PU surface became superhydrophilic the bacterial adhesion becomes independent of bacterium type. In general, it was observed that the impact of topographical changes on the biocompatibility and biofilm formation becomes significantly more profound than that of the surface chemistry alteration.

Hafnium is a passive metal with good biocompatibility and osteogenesis, however, little is known about its resistance to wear and corrosion in biological environments. The corrosion and tribocorrosion behavior of hafnium and commercially pure (CP) titanium in simulated body fluids were investigated using electrochemical techniques. Cyclic polarization scans and open circuit potential measurements were performed in 0.9% NaCl solution and 25% bovine calf serum solution to assess the effect of organic species on the corrosion behavior of the metal. A pin-on-plate configuration tribometer and a three electrode electrochemical cell were integrated to investigate the tribocorrosion performance of the studied materials. The results showed that hafnium has good corrosion resistance. The corrosion density currents measured in its passive state were lower than those measured in the case of CP titanium; however, it showed a higher tendency to suffer from localized corrosion, which was more acute when imperfections were present on the surface. The electrochemical breakdown of the oxide layer was retarded in the presence of proteins. Tribocorrosion tests showed that hafnium has the ability to quickly repassivate after the oxide layer was damaged; however, it showed higher volumetric loss than CP titanium in equivalent wear-corrosion conditions.

Human kallikrein-related peptidases (KLKs) are a family of proteases, the majority of which are found in seminal plasma and have been implicated in semen liquefaction. Here, we examined the clinical value of seminal KLKs in the evaluation of semen quality and differential diagnosis and etiology of abnormal liquefaction and/or viscosity. KLK1-3, 5-8, 10, 11, 13, and 14 were analyzed, using highly specific ELISA assays. Samples were categorized into four clinical groups, according to their state of liquefaction and viscosity. Data were compared between the clinical groups and in association with other parameters of sperm quality, including number of motile sperms, straight line speed, sperm concentration, volume, pH, and patient age. Seminal KLKs were found to be differentially expressed in the four clinical groups. Combination of KLK2, 3, 13, and 14 and KLK1, 2, 5, 6, 7, 8, 10, 13, and 14 showed very strong discriminatory potential for semen liquefaction and viscosity, respectively. Liquefaction state was associated with several parameters of sperm motility. Finally, KLK14 was differentially expressed in asthenospermic cases. In conclusion, the expression level of several seminal plasma KLKs correlates with liquefaction and viscosity indicators of semen quality and may aid in their differential diagnosis and etiology. © 2009 by Walter de Gruyter Berlin New York.