‘Waiting impulsivity’ in isolation-reared and socially-reared rats: effects of amphetamine

Background Rats reared in social isolation exhibit various cognitive and behavioural abnormalities in adulthood. However, impulsivity following this treatment still remains unclear, especially in response to medications used in attention deficit hyperactivity disorder, such as amphetamine. Methods Using an isolation-rearing (IR) manipulation, the present study examined the effects of IR on impulsive action and impulsive choice when also treated with doses of d-amphetamine, by employing the five-choice serial reaction time task (5-CSRTT) and a temporal discounting of reward task (TDRT), respectively. Results IR rats showed similar acquisition of the 5-CSRTT. Amphetamine increased premature responding in both groups; however, IR rats showed less responding overall. For the TDRT, IR rats revealed a greater preference for the large but delayed reward during task acquisition (i.e. were less impulsive) with a higher rate of nose poking during the delay, and exhibited a compressed dose-response function (i.e. reduced dose sensitivity) for amphetamine. Discussion Impulsive action and impulsive choice were reduced in IR rats under certain conditions, and a blunted response to d-amphetamine was found on these measures. These reductions in impulsivity contrast with locomotor hyperactivity normally shown in IR rats and the findings have implications for the utility of IR as a model of psychopathology

New layered compounds BaFMgPn (Pn= P, As, Sb and Bi), transition-metal-free representatives of the LaOAgS structure

Four new transition metal-free pnictide representatives of the LaOAgS structure type were predicted by DFT calculations and found in the BaFMgPn (Pn = P, As, Sb and Bi) family. The compounds adopt the tetragonal space group P4/nmm with the unit cell parameters a/c 4.3097(1) angstrom/9.5032(1) angstrom, 4.3855(1) angstrom/9.5918(1) angstrom, 4.5733(1) angstrom/9.8184(1) angstrom, and 4.6359(1) angstrom/9.8599(1) angstrom, respectively. According to the DFT calculations, these new compounds are semiconductors with band gaps steadily decreasing from Pn = P (ca. 2 eV) to Pn = Bi (ca. 1 eV). The corresponding strontium fluoride and rare-earth oxide analogs are unlikely to exist and have not been observed yet. The trends of the stability within 1111 and structurally and/or chemically related compounds based on a combined consideration of geometry and DFT calculations are discussed

Dynamic and spectral mixing in nanosystems

In the framework of simple spin-boson Hamiltonian we study an interplay between dynamic and spectral roots to stochastic-like behavior. The Hamiltonian describes an initial vibrational state coupled to discrete dense spectrum reservoir. The reservoir states are formed by three sequences with rationally independent periodicities typical for vibrational states in many nanosize systems. We show that quantum evolution of the system is determined by a dimensionless parameter which is characteristic number of the reservoir states relevant for the initial vibrational level dynamics. Our semi-quantitative analytic results are confirmed by numerical solution of the equation of motion. We anticipate that predicted in the paper both kinds of stochastic-like behavior (namely, due to spectral mixing and recurrence cycle dynamic mixing) can be observed by femtosecond spectroscopy methods in nanosystems.Comment: 6 pages, 4 figure

Cs7Sm11[TeO3]12Cl16 and Rb7Nd11[TeO3]12Br16, the new tellurite halides of the tetragonal Rb6LiNd11[SeO3]12Cl16 structure type

The authors thank the Russian Foundation for Basic Researches for the support of this work under Grants No. 14-03-00604_a and 12-03-92604-KO_a. The X-ray study of compound II was made possible due to M.V. Lomonosov Moscow State University Programm of Development. PL thanks the University of St Andrews and EPSRC for DTA Studentships to CB and LJD.Two new rare-earth – alkali – tellurium oxide halides were synthesized by a salt flux technique and characterized by single-crystal X-ray diffraction. The structures of the new compounds Cs7Sm11[TeO3]12Cl16 (I) and Rb7Nd11[TeO3]12Br16 (II) (both tetragonal, space group I4/mcm) correspond to the sequence of [MLn11(TeO3)12] and [M6×16] layers and bear very strong similarities to those of known selenite analogs. We discuss the trends in similarities and differences in compositions and structural details between the Se and Te compounds; more members of the family are predicted.PostprintPeer reviewe

Organic carbon in surface sediments of Chaunskaya Bay (East Siberian Sea): results of pyrolytic analysis using the Rock-Eval method

Relevance. Dictated by the need to assess functioning of the biogeochemical regime of the Arctic region by studying geochemical properties of organic matter of bottom sediments on the example of the Chaunskaya Bay (East-Siberian Sea). Aim. To study the spatial variability of geochemical parameters of organic matter of bottom sediments of the Chaunskaya Bay using the Rock-Eval method, as well as to identify a possible relationship between the parameter TOC and the pelite fraction. Objects. Samples of bottom sediments of the Chaunskaya Bay (East Siberian Sea). Sampling took place in stages from three horizons (upper 0–2 cm, intermediate 2–5 cm, lower 5–10 cm) during a comprehensive scientific expedition to the R/V "Academician Oparin" in September–October 2020. Methods. Granulometric composition of bottom sediments was determined using the Analysette 22 NanoTec particle analyzer (Fritsch, Germany). The analysis of hydrocarbon compounds of organic matter was performed using pyrolytic analysis on the device (Rock Eval 6 Turbo of Vinci Technologies, France). Results. The results of pyrolytic analysis considered by the authors have shown that such factors as the primary productivity of the waters of the studied water area and the processes of erosion of the coastal zone play a decisive role in the formation of the composition of the TOC in bottom sediments of the Chaunskaya Bay. We also do not exclude the contribution of river runoff to the composition of the TOC in bottom sediments; however, we consider it small due to the insignificant inflow of river sediments into the waters of the studied area. The pyrolytic data obtained by us indicate that both the marine component (primary productivity) and the terrigenous component (erosion of the coastal complex) are present in the composition of the TOC in bottom sediments of the studied area

The role of magnesium ions in the molecular mechanism of the action of fluoroquinolones

The article deals a literature review data mainly over the past 13 years (2007 – 2020) on the effect of magnesium ions on the mechanism of action of various fluoroquinolones.В статье представлен обзор литературных данных преимущественно за последние 13 лет (2007 – 2020 гг.) о влиянии ионов магния на механизм действия различных фторхинолонов

Source apportionment of circum-Arctic atmospheric black carbon from isotopes and modeling

Black carbon (BC) contributes to Arctic climate warming, yet source attributions are inaccurate due to lacking observational constraints and uncertainties in emission inventories. Year-round, isotope-constrained observations reveal strong seasonal variations in BC sources with a consistent and synchronous pattern at all Arctic sites. These sources were dominated by emissions from fossil fuel combustion in the winter and by biomass burning in the summer. The annual mean source of BC to the circum-Arctic was 39 ± 10% from biomass burning. Comparison of transport-model predictions with the observations showed good agreement for BC concentrations, with larger discrepancies for (fossil/biomass burning) sources. The accuracy of simulated BC concentration, but not of origin, points to misallocations of emissions in the emission inventories. The consistency in seasonal source contributions of BC throughout the Arctic provides strong justification for targeted emission reductions to limit the impact of BC on climate warming in the Arctic and beyond

Echocardiography in laboratory rabbits

Introduction. Rabbits are used as convenient models for studying drug cardiotoxicity. Echocardiography is one of the most informative non-invasive methods of assessing the cardiovascular system function. In literature, there is no clearly formulated protocol for heart ultrasound examination in rabbits. Purpose was the systematization of literature data on echocardiography techniques in rabbitsЦель работы — систематизация данных литературы о методиках эхокардиографии у кролико