Pathways Related to NLRP3 Inflammasome Activation Induced by Gold Nanorods

The widespread and increasing use of engineered nanomaterials (ENM) increases the risk of human exposure, generating concern that ENM may provoke adverse health effects. In this respect, their physicochemical characteristics are critical. The immune system may respond to ENM through inflammatory reactions. The NLRP3 inflammasome responds to a wide range of ENM, and its activation is associated with various inflammatory diseases. Recently, anisotropic ENM have become of increasing interest, but knowledge of their effects on the immune system is still limited. The objective of the study was to compare the effects of gold ENM of different shapes on NLRP3 inflammasome activation and related signalling pathways. Differentiated THP-1 cells (wildtype, ASC- or NLRP3-deficient), were exposed to PEGylated gold nanorods, nanostars, and nanospheres, and, thus, also different surface chemistries, to assess NLRP3 inflammasome activation. Next, the exposed cells were subjected to gene expression analysis. Nanorods, but not nanostars or nanospheres, showed NLRP3 inflammasome activation. ASC- or NLRP3-deficient cells did not show this effect. Gene Set Enrichment Analysis revealed that gold nanorod-induced NLRP3 inflammasome activation was accompanied by downregulated sterol/cholesterol biosynthesis, oxidative phosphorylation, and purinergic receptor signalling. At the level of individual genes, downregulation of Paraoxonase-2, a protein that controls oxidative stress, was most notable. In conclusion, the shape and surface chemistry of gold nanoparticles determine NLRP3 inflammasome activation. Future studies should include particle uptake and intracellular localization.     

Gamete donation from couple to couple in the new French law

In practice, the partners or spouses of gamete donors are frequently asked permission for the donation. The new French law on bioethics of 29 July 1994 requires that: a) the donor should be one of a couple that has already procreated and b) the written consent of the partner or spouse is obtained. These conditions lead not only to several practical problems in the organisation of donor insemination but also reject a large part of the potential donor population. The two basic qualities demanded of the donors, e.g., paternity and stable relationship, are analyzed. It is proposed that only fatherhood should serve as an exclusionary criterion for sperm donation. The donor need not be a part of a couple at the moment of the donation but if he has a partner at that time her opinion should be heard.     

High strength poly(meth)acrylamide copolymer hydrogels

Summary The hydrogels described here are copolymers of acrylamide and methacrylamide highly cross-linked with piperazine diacrylamide or 4, 7, 10-trioxa-1, 13-tridecanediamine diacrylamide by radical polymerisation in highly concentrated aqueous and aqueous gelatin solutions. The hydrogels were characterised by their compressive strength, refractive indices, densities, ‘free’ water contents and degree of swelling. The hydrogels cross-linked with piperazine diacrylamide gave strong glassy hydrogels, which we have termed “hydroglasses”. Cross-linking with 4, 7, 10-trioxa-1, 13-tridecanediamine diacrylamide, which contains a long flexible spacer, did not result in a more elastic gel. Polymerisation in an aqueous gelatin solution improved the mechanical properties of the gel enormously.     

Cross-linking of ultra-high strength polyethylene fibres by means of electron beam irradiation

Summary Ultra-high strength polyethylene fibres, with a tensile strength at break of 3.0 and 3.4 GPa, were irradiated, at various temperatures in a hydrogen atmosphere, by means of high energy electrons.When the fibres were not annealed, the tensile strength at break was found to decrease upon irradiation, while the Young's modulus remained unchanged. A maximal obtainable tensile strength of 22 GPa was calculated from the decrease in tensile strength and the gel-sol measurements. Gel contents upto 100% were obtained for fibres irradiated in the hexagonal phase.     

Longitudinal growth of polymer crystals from flowing solutions. X. Conditions for continuous growth on the rotor surface

Ultrahigh strength polyethylene fibers can be generated by stress-induced crystallization from a supercooled solution subjected to Couette flow, usually referred to as the “surface-growth” process. Under appropriate conditions, continuous fiber production can be realized for a period as long as 19 days, whereas under other circumstances a rapid interruption of the growth process is met. The present investigation deals with the origin of fiber fracture during “surface growth.” The limiting values of process variables required to maintain continuous growth have been established. Interruption of the continuous growth can occur in three different ways: (1) formation of a closed fiberloop around the rotor; (2) limited crystal growth rate; (3) rapid crystallization, leading to depletion of the gel on the rotor surface. The gel layer is being formed by adsorption of long molecules on to the rotor surface and subsequent “reptation,” resulting in a dense entanglement network of these molecules. These factors determine the boundaries of the triangularly shaped domain for continuous growth in a graph of the two main variables, namely the takeup speed and the rotor speed. Furthermore, it was noticed that the introduction of a wedge-shaped groove in the surface of the Couette rotor leads to a substantial reduction of failure. Continuous growth could be established in the temperature range from 103–125°C when p-xylene was used as a solvent. For p-xylene solutions at a crystallization temperature of 110°C and using a teflon rotor of 115 mm diameter, a maximum takeup speed and rotor speed were 16 and 180 mm/s, respectively. Basically the restrictions of the process appeared to be due to the limited rate of crystallization and rate of adsorption of polyethylene molecules on the surface of the rotor.     

The Quasi Ternary Eutectic System Polyethylene/Hexamethylbenzene/Adamantane

This paper describes the crystallisation and melting behaviour of the quasi ternary system composed of heterodisperse polyethylene, and the diluents hexamethylbenzene and adamantane. The simplified theory of melting point depression according to Flory and Huggins predicts a ternary eutectic point for this system, which was verified experimentally by differential scanning calorimetry. Morphological investigations revealed a complex rod-like eutectic microstructure with characteristic dimensions in the micron range¹.     

The effect of diameter on the mechanical properties of amorphous carbon fibres from linear low density polyethylene

Summary The mechanical properties of amorphous carbon fibres, derived from linear low density polyethylene strongly depend on the fibre diameter, which may be attributed to the presence of a skin/core structure in these fibres. High strength carbon fibres could thus be prepared by using thin precursor filaments, that are obtained by a melt-spinning process, in which the spinline is stretched at an elevated surrounding temperature. Careful carbonization of these precursors gives carbon fibres with a strength of 2.16 GPa, a modulus of 130 GPa and a high strain at break of 3%.     

Ultracompact monolithic integration of balanced, polarizationdiversity photodetectors for coherent lightwave receivers

The authors have monolithically integrated an optical front-end on InP for balanced, polarization-diversity coherent lightwave reception which is only 1.3-mm long. Low on-chip insertion loss (<4.5 dB) and balanced photoresponse (1.05:1 or better) are achieved at 1.5-μm wavelength using straightforward, regrowth-free fabrication. Low-capacitance photodetectors (⩽0.15 pF) are employed for high bandwidth operation     

Shrinkage of highly oriented gel-spun polymeric fibres

Summary The melting and shrinking process of gel-spun hot-drawn UHMWPE fibres has been investigated. Instead of being superheated, the highly oriented fibres start to melt at the fibre ends and shear bands, at a temperature near the equilibrium melting temperature of polyethylene. For draw ratios of 40, the fibre transforms into a ribbon shape upon melting. This change in shape could be prevented by constrained heating before shrinkage. Ribbon-like melting was also observed for gel-spun hot-drawn poly(L-lactide) fibres.