Carbides and Nitrides of Zirconium and Hafnium.

Among transition metal carbides and nitrides, zirconium, and hafnium compounds are the most stable and have the highest melting temperatures. Here we review published data on phases and phase equilibria in Hf-Zr-C-N-O system, from experiment and ab initio computations with focus on rocksalt Zr and Hf carbides and nitrides, their solid solutions and oxygen solubility limits. The systematic experimental studies on phase equilibria and thermodynamics were performed mainly 40-60 years ago, mostly for binary systems of Zr and Hf with C and N. Since then, synthesis of several oxynitrides was reported in the fluorite-derivative type of structures, of orthorhombic and cubic higher nitrides Zr3N4 and Hf3N4. An ever-increasing stream of data is provided by ab initio computations, and one of the testable predictions is that the rocksalt HfC0.75N0.22 phase would have the highest known melting temperature. Experimental data on melting temperatures of hafnium carbonitrides are absent, but minimum in heat capacity and maximum in hardness were reported for Hf(C,N) solid solutions. New methods, such as electrical pulse heating and laser melting, can fill the gaps in experimental data and validate ab initio predictions

Remission in schizophrenia: results of cross-sectional with 6-month follow-up period and 1-year observational therapeutic studies in an outpatient population

<p>Abstract</p> <p>Background</p> <p>A standardized definition of remission criteria in schizophrenia was proposed by the International group of NC Andreasen in 2005 (low symptom threshold for the eight core Positive and Negative Syndrome Scale (PANSS) symptoms for at least 6 consecutive months).</p> <p>Methods</p> <p>A cross-sectional study of remission rate, using a 6-month follow-up to assess symptomatic stability, was conducted in two healthcare districts (first and second) of an outpatient psychiatric service in Moscow. The key inclusion criteria were outpatients with an <it>International Classification of Diseases</it>, 10th edition (ICD-10) diagnosis of schizophrenia or schizoaffective disorder. Remission was assessed using modern criteria (severity and time criteria), PANSS and Global Assessment of Functioning (GAF). Patients who were stable but did not satisfied the symptomatic criteria were included in a further 1-year observational study, with the first group (first district) receiving risperidone (long-acting, injectable) (RLAI) and the second group (second district) continuing to receiving routine treatment. Symptoms were assessed with PANSS, social functioning with the personal and social performance scale, compliance with rating of medication influences scale, and extrapyramidal side effects with the Simpson-Angus scale.</p> <p>Results</p> <p>Only 64 (31.5%) of 203 outpatients met the criteria for symptomatic remission in the cross-sectional study, but at the end of the 6-month follow-up period, 158 (77.8%) were stable (irrespective of remission status). Among these only 53 (26.1%) patients fulfilled the remission criteria. The observational study had 42 stable patients in the RLAI group and 35 in the routine treatment group: 19.0% in the RLAI group and 5.7% in the control group met remission criteria after 12 months of therapy. Furthermore, reduction of PANSS total and subscale scores, as well as improvement in social functioning, was more significant in the first group.</p> <p>Conclusions</p> <p>Only around one-quarter of our outpatient schizophrenic population met full remission criteria. Use of RLAI gave a better remission rate than achieved in standard care with routine treatment. Criteria for remission should take into account clinical course and functioning to support clinical care.</p

Experimental techniques to study structure and thermodynamics at ultra- high temperatures

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Medieval Chersonesus in the Second Half of the 13th Century: a city, a village, a trading post?

The paper addresses the results of the study of medieval Chersonesus as a municipal structure in the second half of 13th century. Historiography was previously dominated by the viewpoint that in that time period Chersonesus remained a major trade, craft and cultural center with buildings of monumental architecture. Currently, it is considered that it remained an ordinary provincial Byzantine center. Specific archaeological complexes with frequent finds of the second half of the 13th century were identified and studied in all districts of the settlement, and were found to be associated with layers of destruction and fires. Two layers of destruction (fire), dated to the 13th and 14th centuries, have been recorded in the Port district. These late Byzantine layers are represented by all complexes of materials (primarily, archaeological), which allow to conclude that at the beginning of the second half of the 13th century Chersonesus was a typical provincial Byzantine city on the edge of the Golden Horde Ecumene. At the turn of the fourth quarter of the 13th century (in 1278), the city was destroyed and has not been restored, with the exception of the Port district, which became a small 14th century village

Tunable Low Density Palladium Nanowire Foams

Nanostructured palladium foams offer exciting potential for applications in diverse fields such as catalyst, fuel cell, and particularly hydrogen storage technologies. We have fabricated palladium nanowire foams using a cross-linking and freeze-drying technique. These foams have a tunable density down to 0.1% of the bulk, and a surface area to volume ratio of up to 1,540,000:1. They exhibit highly attractive characteristics for hydrogen storage, in terms of loading capacity, rate of absorption and heat of absorption. The hydrogen absorption/desorption process is hysteretic in nature, accompanied by substantial lattice expansion/contraction as the foam converts between Pd and PdHx.Comment: 17 pages, 4 figure

Ab initio guided minimal model for the "Kitaev" material BaCo2_2(AsO4_4)2_2: Importance of direct hopping, third-neighbor exchange and quantum fluctuations

We present a simple three-parameter exchange model to describe the interactions of the lowest doublet of the honeycomb cobaltate BaCo$_2$(AsO$_4$)$_2$, which has been proposed as a possible candidate for Kitaev physics. Remarkably, it is the third-neighbor interactions, both isotropic and anisotropic, that are responsible for the unique ground state of BaCo$_2$(AsO$_4$)$_2$, stabilized by quantum fluctuations. By considering two {\it ab initio}-based complementary approaches, we analyze the electronic structure of BaCo$_2$(AsO$_4$)$_2$ and extract effective spin models that justify the minimal model. Both methods show that the dominant direct hopping makes the bond-dependent Kitaev term negligible moving the material away from the sought-after spin-liquid regime. Moreover, a significantly large third-nearest neighbor hopping supports the observed importance of the third-neighbor interactions in the stabilization of the standout double-zigzag ground state of BaCo$_2$(AsO$_4$)$_2$.Comment: 8 pages, 4 figure

Two-step antiferromagnetic transition and moderate triangular frustration in Li2Co(WO4)2

We present a detailed investigation of the magnetic properties of the spin-$\frac{3}{2}$ system Li$_2$Co(WO$_4$)$_2$ by means of magnetic susceptibility and specific heat. Our experimental results show that in Li$_2$Co(WO$_4$)$_2$ a short-range antiferromagnetic (AFM) correlations appear near $\chi$$_{max}$ $\sim$ 11 K and two successive long-range AFM phase transitions are observed at T$_{N1}$$\sim$ 9 K and T$_{N2}$$\sim$ 7 K. The frustration factor, $\mid$$\Theta$$\mid$/T$_{N1}$$\sim$3, indicates that the system is moderately frustrated, which is identifiable by the broken triangular symmetry within both $ab$- and $bc$-planes for the triclinic crystal structure. The magnetic isotherm at temperatures below T$_{N2}$ shows a field-induced spin-flop transition, and a complete H-T phase diagram for the two-step AFM system is mapped. $Ab$~$initio$ band structure calculations suggest that the strongest exchange coupling does not correspond to the shortest Co-Co distance along the $a$-axis, but rather along the diagonal direction through a Co-O-W-O-Co super-superexchange path within the $bc$-planeComment: 7 Pages, 10 Figure

The Biomarker and Therapeutic Potential of Circular Rnas in Schizophrenia

Circular RNAs (circRNAs) are endogenous, single-stranded, most frequently non-coding RNA (ncRNA) molecules that play a significant role in gene expression regulation. Circular RNAs can affect microRNA functionality, interact with RNA-binding proteins (RBPs), translate proteins by themselves, and directly or indirectly modulate gene expression during different cellular processes. The affected expression of circRNAs, as well as their targets, can trigger a cascade of events in the genetic regulatory network causing pathological conditions. Recent studies have shown that altered circular RNA expression patterns could be used as biomarkers in psychiatric diseases, including schizophrenia (SZ); moreover, circular RNAs together with other cell molecules could provide new insight into mechanisms of this disorder. In this review, we focus on the role of circular RNAs in the pathogenesis of SZ and analyze their biomarker and therapeutic potential in this disorder.publishedVersio

Predictability problems of global change as seen through natural systems complexity description. 2. Approach

Developing the general statements of the proposed global change theory, outlined in Part 1 of the publication, Kolmogorov's probability space is used to study properties of information measures (unconditional, joint and conditional entropies, information divergence, mutual information, etc.). Sets of elementary events, the specified algebra of their sub-sets and probability measures for the algebra are composite parts of the space. The information measures are analyzed using the mathematical expectance operator and the adequacy between an additive function of sets and their equivalents in the form of the measures. As a result, explanations are given to multispectral satellite imagery visualization procedures using Markov's chains of random variables represented by pixels of the imagery. The proposed formalism of the information measures application enables to describe the natural targets complexity by syntactically governing probabilities. Asserted as that of signal/noise ratios finding for anomalies of natural processes, the predictability problem is solved by analyses of temporal data sets of related measurements for key regions and their background within contextually coherent structures of natural targets and between particular boundaries of the structures

Predictability problems of global change as seen through natural systems complexity description. 1. General Statements

The overall problem of global change is considered as the mathematical discrete dynamics discipline that deals with the sets, measures and metrics (SMM) categories in information sub-spaces. The SMM conception enables to unify techniques of data interpretation and analysis and to explain how effectively the giant amounts of information from multispectral satellite radiometers and ground-based instruments are to be processed. It is shown that Prigogine's chaos/order theory and Kolmogorov's probability space are two milestones in understanding the predictability problems of global change. The essence of the problems is maintained to be in filtering out a “useful signal” that would spread from key regions of the globe as compared to their background. Global analysis, interpretation and modelling issues are outlined in the framework of incorrect mathematical problems and of the SMM categories, which contribute to solving the comparability problem for different sets of observations