Impairment of cellular immunity in west Greenland sledge dogs (Canis familiaris) dietary exposed to polluted minke whale (Balaenoptera acutorostrata) blubber

Minke whale (Balaenoptera acutorostrata) blubber is rich in organohalogen contaminants, mercury, and n-3 fatty acids. In the present study we show that a daily intake of 50-200 g of minke whale blubber causes an impairment of the nonspecific and specific cellular immune system in the West Greenland sledge dog (Canis familiaris). Immune reactions were measured by mitogen (PHA, Con A) and antigen (KLH) intradermal testing, and as the study used exposure levels similar to those of Inuits and polar bears (Ursus maritimus), it is reasonable to infer that Inuits and polar bears suffer from similar decreased resistance to diseases. It is speculated that food sources are depleted by thinning sea ice due to climate change and that more research should assess the forecasted rise in additive immunopathy effects in polar bears. Additionally, our study suggests that the fatty acid composition may be of importance when investigating combined immunotoxic effects of contaminated food resources in future Inuit and polar bear studies.     

Solar orbital power: Sustainability analysis

Solar power plants positioned in space for terrestrial electricity use have been proposed due to the ever-rising world energy consumption and its environmental impacts. This idea is analysed here in the context of sustainability of such power generation. To that end we have performed some new economic, environmental and social effects analysis of electricity generation by solar space power plants of both photovoltaic and solar thermal types power using the best currently available technology. The plants in the analysis were assumed to be in different Earth orbits, or on the Moon built by a robotised factory. One of our results is that both economically and environmentally the best scenario may be to launch a thermal solar power plant to the geostationary orbit from the Moon. Electricity produced in this way could be economically competitive to that generated by fossil fuels on Earth already for as few as 100 space power plants of about 5-10 GW each. This option is also deemed socially responsible with its capacity to reduce poverty with large amounts of cheap clean energy, and environmentally friendly, because it produces more than a hundred times less emissions than the same amount of electricity produced from fossil fuels on Earth.     

Styrene polymerization with a macroinitiator having siloxane units

Block copolymers containing segments of poly(dimethylsiloxane) (PDMS) and polystyrene were synthesized. Dihydroxy terminated PDMS M_n 2500 g/mol, was reacted with an ali-phatic diisocyanate (isophorone diisocyanate) and an aliphatic hydroperxide (t-butyl hy-droperoxide). The resulting polymeric peroxycarbamate having siloxane units (a new mac-roinitiator) was used as free radical initiator for vinyl polymerization of styrene. Formation of block copolymers was illustrated by several characterization methods such as chemical and spectroscopic analysis, fractionation, and GPC. Mechanical and thermal characterization of the copolymers were made by stress–strain tests and DSC. The surface properties and the morphology of the block copolymers were investigated by contact angle measurements and SEM. © 1996 John Wiley & Sons, Inc.     

Electroconductive polymer composite: Fibrous carrier–polypyrrole

Obtaining a “hybrid” electroconductive polymer composite material on the basis of a fibrous carrier and polypyrrole (pPy) was studied. As fibrous carriers, polyacrylonitrile (PAN) and chemically modified polyacrylonitrile possessing ion-exchange properties were used. FeCl₃, chosen as an initiator for oxidative polymerization of pyrrole (Py), was introduced in the fibrous matrix by sorption from an aqueous or diethylether solution. The polypyrrole film was deposited onto/in a matrix prepared in this way by polymerization of pyrrole in a vapor phase, from the vacuum, or from a solution of Py in toluene. In some cases, an additional doping of the obtained (electroconductive) pPy film, with iodine vapors in the vacuum, was also applied. An electroconductive composite material, with volume resistivity of about 10 Ω cm, was obtained. The results, related to the different nature of the fibrous carrier and different procedures for the oxidizer introduction or pPy deposition, were discussed. © 1996 John Wiley & Sons, Inc.     

Armed to the Teeth—The Oral Mucosa Immunity System and Microbiota

The oral cavity is inhabited by a wide spectrum of microbial species, and their colonization is mostly based on commensalism. These microbes are part of the normal oral flora, but there are also opportunistic species that can cause oral and systemic diseases. Although there is a strong exposure to various microorganisms, the oral mucosa reduces the colonization of microorganisms with high rotation and secretion of various types of cytokines and antimicrobial proteins such as defensins. In some circumstances, the imbalance between normal oral flora and pathogenic flora may lead to a change in the ratio of commensalism to parasitism. Healthy oral mucosa has many important functions. Thanks to its integrity, it is impermeable to most microorganisms and constitutes a mechanical barrier against their penetration into tissues. Our study aims to present the role and composition of the oral cavity microbiota as well as defense mechanisms within the oral mucosa which allow for maintaining a balance between such numerous species of microorganisms. We highlight the specific aspects of the oral mucosa protecting barrier and discuss up-to-date information on the immune cell system that ensures microbiota balance. This study presents the latest data on specific tissue stimuli in the regulation of the immune system with particular emphasis on the resistance of the gingival barrier. Despite advances in understanding the mechanisms regulating the balance on the microorganism/host axis, more research is still needed on how the combination of these diverse signals is involved in the regulation of immunity at the oral mucosa barrier.     

MoxWx–1S2 Nanotubes for Advanced Field Emission Application

Transition metal dichalcogenide (TMDC) nanotubes complement the field of low-dimensional materials with their quasi-1D morphology and a wide set of intriguing properties. By introducing different transition metals into the crystal structure, their properties can be tailored for specific purpose and applications. Herein, the characterization and a subsequent preparation of single-nanotube field emission devices of Mo_xW_x-1S₂ nanotubes prepared via the chemical vapor transport reaction is presented. Energy-dispersive X-ray spectroscopy, Raman spectroscopy, and X-ray diffraction  indicate that the molybdenum and tungsten atoms are randomly distributed within the crystal structure and that the material is highly crystalline. High resolution transmission electron microscopy  and electron diffraction (ED) patterns further corroborate these findings. A detailed analysis of the ED patterns from an eight-layer nanotube reveal that the nanotubes grow in the 2H structure, with each shell consists of one bilayer. The work function of the nanotubes is comparable to that of pure MoS₂ and lower of pure WS₂ NTs, making them ideal candidates for field emission applications. Two devices with different geometrical setup are prepared and tested as field emitters, showing promising results for single nanotube field emission applications.     

Physiologically-Based Pharmacokinetic Modeling of the Postbiotic Supplement Urolithin A Predicts its Bioavailability Is Orders of Magnitude Lower than Concentrations that Induce Toxicity,but also Neuroprotective Effects

Scope

A range of health benefits are attributed to consuming urolithin A (UA), such as improved muscle health, anti-aging activity, and neuroprotection, whereas few studies raise possible adverse effects at high doses, including genotoxicity and estrogenic effects. Therefore, understanding UA bioactivity and safety depends on its pharmacokinetics. However, there is no physiologically-based pharmacokinetic (PBPK) model available for UA, thus limiting reliable assessment of effects observed from in vitro experimentation.

Methods and results

We characterizes glucuronidation rates of UA by human S9 fractions. Partitioning and other physicochemical parameters are predicted using quantitative structure–activity relationship tools. Solubility and dissolution kinetics are determined experimentally. These parameters are used to construct a PBPK model, and results are compared with data from human intervention studies. We evaluates how different supplementation scenarios may influence UA plasma and tissue concentrations. Concentrations at which either toxic or beneficial effects are previously observed in vitro appear unlikely to be achieved in vivo.

Conclusion

A first PBPK model for UA is established. It enables prediction of systemic UA concentrations and is critical for extrapolating in vitro results to in vivo uses. Results support the safety of UA, but also challenge the potential for readily achieving beneficial effects by postbiotic supplementation.