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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.forsciint.2007.02.027 Byline: Alexander Perelygin (a), Alexander Kuchkin (b), Nikolay Kharkov (a), Tatyana Moskvina (c) Keywords: Platinum group metals; PGM-containing intermediate products; Source of origin of products Abstract: In early 1990s some organized criminal groups started to develop a new field of illegal business, which involved thefts of intermediary products from mining and metal-producing plants in Russia and in the south of Africa. Since local sulfide copper/nickel ores contain certain concentrations of precious and platinum group metals (PGMs), the intermediary products recovered at different stages of metallurgical transformation of these ores are materials of high commercial value. Illicit transportation and refining of these materials in Western Europe and North America has evolved into a large-scale business, where a lot of unlawful revenues are being laundered. The most important tasks in combating this organized crime are as follows: to establish the facts when some PGM-containing semi-products had been received at certain refineries; to carry out the identification of these semi-products; and to prove that these semi-products had been produced by a certain company. As a rule, it is not difficult to establish the identity of a 'clean product'. However, when a material is a mix of several semi-products or a mix of some semi-product with masking substances, the identification of individual components becomes an extremely complicated task. The purpose of developing the 'complex procedure for establishing the nature and source of origin of precious metal-bearing products of mining and metallurgical operations' was to make possible the identification of complex mixes comprised of various metallurgical semi-products. In the complex procedure that we have developed to characterize dispersed materials, distribution of particles by their elemental composition (the so-called 'pseudophase' composition) was used instead of mineralogical composition. To determine the 'pseudophase' composition by the method of scanning electron microscopy with X-ray spectral microanalysis (SEM-EDX), a representative sample of material containing not less than 1000 particles was analyzed. All microparticles can be divided into several types. Each type is characterized by an association of chemical elements contained. The first stage includes the study of elemental composition by inductively coupled plasma optical emission spectrometry and inductively coupled plasma mass-spectrometry; and the study of phase composition by X-ray diffractometry. The results of each study are compared with data in the Data Base. In case of coincidence with one of the products with respect to all diagnostic features, the type of product and its source of origin are defined accordingly. If the features of the sample under analysis detected by the aforementioned methods do not coincide with any of the product types represented in Data Base, it is necessary to examine elemental composition and morphology of separate particle contained in the substance using SEM-EDX. If some particles characterized by features coinciding with features of particles belonging to any product or products from Data Base are found, this product or a mixture of products is assumed to be present in the composition of the substance under analysis. The assumption that the substance is a mixture can be verified by juxtaposing all previously determined features of the analyzed sample with the features of the pattern mixture (superposition) of the appropriate types of products represented in Data Base. Depending on the results of this verification the corresponding conclusion can be made. Author Affiliation: (a) Mining and Metallurgical Company 'Norilsk Nickel', Russia (b) Institute of Criminalistics of the Russian Federal Security Service, Russia (c) Russian Federal Center of Forensic Science (RFCFS), 13 Build. 2 Khokhlovsky Sidestreet, Moscow 109028, Russia Article History: Received 31 July 2006; Accepted 28 February 2007

A study on elemental composition, phase composition, microstructure, nanohardness and fracture micromechanisms of the surface layers obtained by ion-plasma treatment of a stable CrNiMo austenitic stainless steel with different initial microstructures has been carried out. In cold-rolled specimens, containing a high dislocation density and deformation-induced low- and high-angle boundaries and possessing structural elements of 330 nm in size, interstitial concentration (carbon and nitrogen) is much higher than that for cold-rolled and annealed specimens with a similar size of structural elements. After ion-plasma treatment, a surface nanohardness of the pre-deformed specimens is higher by 8 GPa than one for specimens annealed after cold rolling. Deformation-assisted microstructure accumulates carbon more likely than nitrogen under ion-plasma treatment. These results provide experimental support for decisive role of high dislocation density and deformation-assisted well-developed microstructure in accumulation and bulk diffusion of interstitials under ion-plasma treatment of steel. Unlabelled Image • Pre-deformation stimulates accumulation of interstitials under ion-plasma treatment. • Deformation-assisted defects suppress bulk diffusion of carbon under IPT. • Deformation-associated microstructure favors decomposition of austenite under IPT. • As-deformed specimens possess higher surface nanohardness after IPT compared to annealed one. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of (spiro)pyranocoumarin oximes were successfully subjected to Beckmann rearrangement in the presence of PPA. • The rearrangement led to the efficient formation of unusual imines as major products via 2,3-alkyl migration. • The expected lactams were obtained as minor products with insignificant yields via 1,2-alkyl migration. • These findings demonstrate a new approach for the selective synthesis of complex and diverse imines with potential applications in synthetic organic chemistry and medicinal chemistry. This paper presents the successful implementation of Beckmann rearrangement on a series of (spiro)pyranocoumarin oximes in polyphosphoric acid (PPA) medium. The method demonstrated excellent proficiency in the synthesis of unexpected imines as major products and amides as minor products. The labeled 15NH 2 OH·HCl control experiment yielded oxime and rearrangement products that incorporated the 15N label. Furthermore, we have proposed a possible rearrangement mechanism. NMR spectroscopy data (correlation HMBC and 15N NMR) confirmed the structure of the synthesized products. These findings provide a new and efficient approach for constructing complex imines with diverse applications in synthetic organic chemistry. [ABSTRACT FROM AUTHOR]

The effects of electrochemical hydrogen charging on the stress relaxation and strain-aging of 〈111〉- and 〈001〉-oriented single crystals of Hadfield steel were studied under tension at room temperature. An orientation dependence of stress relaxation and strain-aging-assisted yield-drop phenomena was observed for hydrogen-free 〈111〉- and 〈001〉- oriented single crystals. Hydrogen charging up to five hours increased the stress relaxation rate for slip-associated deformation in 〈001〉-oriented single crystals and decreased it for twinning-assisted deformation in 〈111〉-oriented specimens. The present results demonstrate that different mechanisms dominate the interaction of hydrogen with dislocations, stacking faults and twins. [ABSTRACT FROM AUTHOR]

The efficient synthesis of enaminoketones of 2′-carboxamidodeoxybenzoins and subsequent transformation into 1-oxo-3-aryl-1 H -isochromene-4-carbaldehydes via an intermolecular cyclization under weakly acidic conditions has been demonstrated. Mild reaction conditions, a simple work-up procedure, short reaction times and high yields are the advantages of the presented method. [ABSTRACT FROM AUTHOR]

Background: At least 10 large and rare recurrent DNA copy number variants (CNVs) have been identified as risk factors for schizophrenia and other neurodevelopmental disorders. Because such conditions are associated with reduced fecundity, these pathogenic CNVs should be filtered out from the population by selection and must be replenished by de novo events. Methods: To estimate the mutation rate (μ) for these CNVs and the selection pressure (s) against them, we first conducted a literature review on the rate of each of these CNVs in the population and the rate of their de novo occurrence. In each generation, the number of CNVs lost because of reduced fertility must be replenished by the same number of de novo CNVs. Therefore, the observed ratio of de novo versus all (inherited + de novo) CNVs approximates the selection coefficient (s) of that CNV. The mutation rate approximates to μ = s × q, where q is the frequency of the CNV in the population. Results: High selection pressure operates at all these loci (s = .12 – .88), suggesting that following de novo occurrence, each of these CNVs persists in the population in only a few generations. The mutation rate for each CNV is high, affecting between 1:3500 and 1:30,000 individuals. The rarest CNVs have the highest selection coefficients. Conclusions: The CNVs that increase risk to develop schizophrenia are caused by recent de novo mutations and are under strong selection pressure. They persist in the population because of high mutation rates. [Copyright &y& Elsevier]

Background: Given that genome-wide association studies (GWAS) of psychiatric disorders have identified only a small number of convincingly associated variants (single nucleotide polymorphism [SNP]), there is interest in seeking additional evidence for associated variants with tests of gene–gene interaction. Comprehensive pair-wise single SNP–SNP interaction analysis is computationally intensive, and the penalty for multiple testing is severe, given the number of interactions possible. Aiming to minimize these statistical and computational burdens, we have explored approaches to prioritize SNPs for interaction analyses. Methods: Primary interaction analyses were performed with the Wellcome Trust Case-Control Consortium bipolar disorder GWAS (1868 cases, 2938 control subjects). Replication analyses were performed with the Genetic Association Information Network bipolar disorder dataset (1001 cases, 1033 control subjects). The SNPs were prioritized for interaction analysis that showed evidence for association that surpassed a number of nominally significant thresholds, are within genome-wide significant genes, or are within genes that are functionally related. Results: For no set of prioritized SNPs did we obtain evidence to support the hypothesis that the selection strategy identified pairs of variants that were enriched for true (statistical) interactions. Conclusions: The SNPs prioritized according to a number of criteria do not have a raised prior probability for significant interaction that is detectable in samples of this size. We argue that the use of significance levels reflecting only the number of tests performed, as is now widely accepted for single SNP analysis, does not offer an appropriate degree of protection against the potential for GWAS studies to generate an enormous number of false positive interactions. [ABSTRACT FROM AUTHOR]

The literature on the synthesis of saturated and partially saturated (sp 3-enriched) boronic acids, boronates, and trifluoroborates is surveyed comprehensively starting from the early 1960s to 2020, focusing mainly on results published in the last decade. The synthetic methods are subdivided into two large groups: those based on the boronate moiety introduction and those commencing from boron-containing substrates. In particular, borylations at various functional groups or even C–H bonds, hydroborations, inter- and intramolecular carboborations, cycloadditions, and metathesis of alkenyl boronates are discussed, together with other methods. [Display omitted] [ABSTRACT FROM AUTHOR]

• Porous structure prepared by environmental crazing accelerates the PLA degradation. • Average weight of crazed PLA decreases by 2 times after exposure to PBS at 37 °C for 6 weeks. • Structural modification by crazing allows to control a location of intense degradation. • Dicalcium phosphate dihydrate accelerates PLA hydrolysis in the crazes. Hydrolytic degradation of porous polylactide (PLA) films with various porosity and morphology has been thoroughly investigated. It has been found that the structural and mechanical modification of PLA films by the environmental crazing mechanism results in the formation of a porous structure, is accompanied by the change in molecular-weight characteristics of the polymer and affects the localization and rate of its hydrolytic degradation. After the films were exposed in phosphate-buffered saline solution at 37 °C for 6 weeks, their average molecular weights M W and M N decreased by 1.5–2 and 3–5 times respectively, while their dispersity Đ M increased to 4–5. For PLA films containing alternating porous crazes and nonporous bulk parts, the hydrolysis leads to the appearance of bimodal molecular-weight distribution (MWD) curves. The degradation of the polymer material localizes predominantly at the craze–bulk polymer interfaces, thereby leading to a rather rapid and significant decrease in the deformation and strength properties of the films, which eventually become brittle. For PLA films, that have completely passed to the fibrillar-porous structure during the hydrolytic degradation, the character of the MWD curves remains preserved, but they gradually widen and shift toward lower molecular weights. The destruction of similar samples occurs uniformly throughout the volume, and the changes in their structural and mechanical parameters are not so abrupt, and even after the hydrolysis for 6 weeks their strength remains at a level of 90 MPa. When the porous matrix of PLA is filled with calcium phosphate (up to 30 wt%), the degradation of the polymer material occurs predominantly in the crazes and hardly proceeds in the bulk parts. The approaches proposed using PLA as an example enable one to control the degradation processes in polymers by varying their structural and morphological characteristics and incorporating inorganic fillers, thus opening new ways to the creation of bioactive and biodegradable materials with predictable degradation times. [ABSTRACT FROM AUTHOR]

Virtual reality opens new ways for reconstructing, preserving and exhibiting clothing and textiles. This applies particularly to those from an archaeological context, which can be incomplete, damaged or fragile. Despite the possibilities of computer technology, such as computer graphics (CG) and computer-aided design (CAD), its potential has only been superficially explored. This article showcases its possibilities by focussing upon the equipment of a Germanic warrior from the 2nd–4th century AD. His panoply consists of trousers, a tunic, shoes, a mail coat, an under-armour garment and a belt. CG and CAD tools, such as stress analysis and strain analysis, were applied to visualize and examine the behaviour of his equipment. The military clothing of the Germanic warrior proves very functional in terms of physics, materials science, anatomy and biomechanics. In other words, his clothing and armour result very suitable for warfare. This case study demonstrates that digital reconstructions can be more than scientific visualisation, but also a new and powerful research tool, generating new insights into archaeological artefacts. [ABSTRACT FROM AUTHOR]

This article presents a new method for examining mail through the use of digital reconstruction and computer simulation. The method allows the physical and mechanical properties of mail artefacts to be reconstructed, which otherwise remain hidden, by performing tests in a virtual environment. Ten archaeological finds, dating between 300 BC and 1000 AD, were parameterized and reconstructed. Testing procedures were developed to measure the properties of the mail fabrics. A physics engine was employed to simulate the behaviour of the specimens under the influence of external forces. Six important characteristics (i.e. stretch, stiffness, number of rings per unit area, mass per unit area, thickness, and covered area ratio) were calculated for each specimen and compared to each other to identify distinctive features. This was followed by a correlation analysis to understand how the rings' geometrical parameters influence the properties of the mail fabric and how these properties are balanced. The method demonstrates that not all mail is alike and that certain characteristics were favoured during certain times. The first careful results point to Iron Age mail being heavy and stiff, while mail during the Principate became much lighter and more flexible. During Late Antiquity this was again reversed in favour of heavier mail. The subsequent medieval period up to the 10th century demonstrates a balance between these characteristics. [ABSTRACT FROM AUTHOR]

The influence of various liquid media (aliphatic alcohols, water-alcohol solutions, saturated hydrocarbons, and organosilicon liquids) on the development of uniaxial deformation and nucleation of crazes in amorphous polylactide (PLA) films has been studied. It has been found that in the presence of the liquids the tensile stress during the polymer deformation decreases by 3–4 times. According to the Griffith's theory, linear dependences (with an accuracy of R 2  = 0.96–0.97) have been revealed between the yield point or the flow stress of PLA and the square root of product of the elasticity modulus of the polymer in a liquid and the interfacial surface energy at the polymer-liquid medium interface calculated using the Owens-Wendt equation. The data obtained may be used to predict the critical mechanical stress at which crazes will be initiated in PLA. [ABSTRACT FROM AUTHOR]