Unusual polarimetric properties for interstellar comet 2I/Borisov.

So far, only two interstellar objects have been observed within our Solar System. While the first one, 1I/'Oumuamua, had asteroidal characteristics, the second one, 2I/Borisov, showed clear evidence of cometary activity. We performed polarimetric observations of comet 2I/Borisov using the European Southern Observatory Very Large Telescope to derive the physical characteristics of its coma dust particles. Here we show that the polarization of 2I/Borisov is higher than what is typically measured for Solar System comets. This feature distinguishes 2I/Borisov from dynamically evolved objects such as Jupiter-family and all short- and long-period comets in our Solar System. The only object with similar polarimetric properties as 2I/Borisov is comet C/1995 O1 (Hale-Bopp), an object that is believed to have approached the Sun only once before its apparition in 1997. Unlike Hale-Bopp and many other comets, though, comet 2I/Borisov shows a polarimetrically homogeneous coma, suggesting that it is an even more pristine object.

The 67P/Churyumov-Gerasimenko observation campaign in support of the Rosetta mission.

We present a summary of the campaign of remote observations that supported the European Space Agency's Rosetta mission. Telescopes across the globe (and in space) followed comet 67P/Churyumov-Gerasimenko from before Rosetta's arrival until nearly the end of the mission in September 2016. These provided essential data for mission planning, large-scale context information for the coma and tails beyond the spacecraft and a way to directly compare 67P with other comets. The observations revealed 67P to be a relatively 'well-behaved' comet, typical of Jupiter family comets and with activity patterns that repeat from orbit to orbit. Comparison between this large collection of telescopic observations and the in situ results from Rosetta will allow us to better understand comet coma chemistry and structure. This work is just beginning as the mission ends-in this paper, we present a summary of the ground-based observations and early results, and point to many questions that will be addressed in future studies.This article is part of the themed issue 'Cometary science after Rosetta'.

Platinum(II), platinum(IV), and palladium (II) complexes of amino substituted phosphine oxides: synthesis, characterization, and antitumor activity.

The complexes [Pt(dapo)2Cl2], [PtNH3(dapo)Cl2], [Pt(py)(dapo)Cl2], [Pt(mbpo)Cl2].H2O, [Pt(mbpo)(OH)2Cl2].H2O, [Pd(dapo)2Cl2], and [Pd(mbpo)Cl2], where dapo is dimethyl aminomethylphosphine oxide and mbpo is methyl bis(aminomethyl)phosphite oxide have been synthesized and characterized by elemental analyses, electric conductivity, infrared, 1H NMR and electronic spectra. The ligands are found to be coordinated only via the amino groups. The complexes are of cis-square planar configuration with the exception of [Pt(mbpo)(OH)2Cl2].H2O which is pseudo-octahedral. An in vivo antitumor screening of the complexes against Leukemia L1210 was performed. A considerable activity (T/C = 233%) was observed for [PtNH3(dapo)Cl2]. The activity of the remaining complexes was below the accepted criterion.

Substituted ethan phosphonic acid esters as reagents for the separation of molybdenum from rhenium by solvent extraction.

New esters of the ethan phosphonic acids have been synthesized and their extraction properties studied with respect to Mo(VI), Re(VII), Fe(III),Au(III),Tl(III) and Sb(V). A possibility is shown for the analytical separation of molybdenum from rhenium (beta = 700). The state of these new extraction agents in carbon tetrachloride solution, and the mechanism of the extraction processes, have been investigated by means of infrared spectra.

Analytical characterization of some pyrazolones and their copolymers with some vinyl compounds.

Some new pyrazolones have been synthesized and their copolymers with styrene, methylmethacrylate and methacrylic acid prepared. The pyrazolones and their styrene and methylmethacrylate copolymers are insoluble in water but form chelate complexes with some alkaline-earth and transition metal ions. The water-soluble methacrylic acid copolymers do not form complexes with these elements, however, probably because of hydrogen-bonding of the chelating groups to the methacrylic acid carboxyl groups. Special attention was paid to the complexation of Au(III), which was assumed to proceed mainly through the nitrogen atoms of the pyrazolone ring.

New chelating sorbents based on pyrazolone containing amines immobilized on styrene-divinylbenzene copolymer-I Synthesis and analytical characterization.

A series of new cheating sorbents has been prepared by modification of styrene-divinylbenzene copolymer with different pyrazolone-containing amines. The substances were characterized by elemental analysis and infared spectroscopy. The complexation ability of the sorbents towards alkali, alkaline-earth, transition and precious metals has been studied. The new sorbents may successfully be applied to the simultaneous preconcentration of alkaline-earth and transition elements in neutral medium and to the selective separation of precious metals in acidic medium.

[The results of toxicological research on dental alloys containing Ni, Cr and Co using the implantation method]. / Rezul'taty toksikologicheskogo issledovaniia stomatologicheskikh splavov, soderzhashchikh Ni, Cr, Co, metodom implantatsii.

Biocompatibility of 7 dentistry alloys containing 5 do 70% of Ni but not containing Be was studied by implantation of these alloys into femoral muscles of 360 white rats. Tissue directly adjacent to alloy samples, regional lymph nodes, and viscera were under study. The detected changes were approximately similar in different animal groups and similar to the changes in the reference group, this permitting the authors to consider the suggested allows biologically indifferent.

[An automated device for x-ray fluorescence analysis and its use in space and clinical medicine]. / Avtomatizirovannaia ustanovka dlia rentgenofliuorestsentnogo analiza i ee ispol'zovanie v nekotorykh zadachakh kosmicheskoi i klinicheskoi meditsiny.

An experimental unit for radiofluorescent analysis using the REIS-I x-ray emitter, a Si (Li) detector, an analyser with the NOIKA LP-4900 microprocessor and appropriate soft ware was devised for a study of some aspects of metabolism and kinetics of a number of electrolytes playing an important role in the state of water-salt homeostasis of the organism of man and animals. Methodological approaches to quantitative determination of the native content of plasma trace elements and macrocells: S, Cl, K, Ca and stable bromine administered for determination of extracellular fluid volume--were developed. This method can be used for determination of quantitative indices of the above functions in healthy men and animals during outer space flights, ground mock-up experiments, for clinical investigations in diagnosis of subpathological conditions and for control of therapeutic efficacy.

[Characteristics of the hydration status of patients with hypothyroidism]. / Osobennosti gidratatsionnogo statusa u bol'nykh gipotireozom.

The hydratation status of 15 patients of various age groups with hypothyrosis was studied using nuclear physical methods. Their body composition was calculated. All the examinees demonstrated considerable hyperhydratation of the extracellular water sector with prevailing liquid accumulation in the interstitial space. Some changes in the infrastructure of the hydratation status including those in the nature of interrelationships of liquid media, were noted. The dependence of the hydratation status and its infrastructure in patients with hypothyrosis on age and gravity of disease but not on its duration was revealed.

[Effect of space flight factors on hydration homeostasis in monkeys]. / Vliianie faktorov kosmicheskogo poleta na gidratatsionnyi gomeostaz obez'ian.

Using nuclear physics methods, hydration homeostasis of three monkeys flown on Cosmos-1514 and Cosmos-1667 was investigated. Measurements were made before flight 1.5 hours after touchdown and during the recovery period. Total water content, extracellular and tissue fluid volumes were measured and intracellular and interstitial fluid volumes were calculated. Postflight, all the animals showed hydration status changes of similar sign: total water content, intracellular and extracellular fluid volumes decreased. Most significant changes occurred in tissue and interstitial fluid volumes. Hydration status responses to space flight factors were variable and the above changes disappeared in the course of the recovery period. The variations recorded were viewed as adaptive.