Pattern formation during diffusion limited transformations in solids

We develop a description of diffusion limited growth in solid-solid transformations, which are strongly influenced by elastic effects. Density differences and structural transformations provoke stresses at interfaces, which affect the phase equilibrium conditions. We formulate equations for the interface kinetics similar to dendritic growth and study the growth of a stable phase from a metastable solid in both a channel geometry and in free space. We perform sharp interface calculations based on Green's function methods and phase field simulations, supplemented by analytical investigations. For pure dilatational transformations we find a single growing finger with symmetry breaking at higher driving forces, whereas for shear transformations the emergence of twin structures can be favorable. We predict the steady state shapes and propagation velocities, which can be higher than in conventional dendritic growth.Comment: submitted to Philosophical Magazin

Antibacterial Therapy for Purulent-Septic Complications in Patientswith Combat Related Penetrating Craniocerebral Gunshot Wounds

Aim - to evaluate pathogens and their susceptibility to antibiotic therapy (ABT) in combat-related penetrating craniocerebral gunshot wound (PCGW) patients and develop recommendations for treatment of post-traumatic meningoencephalitis. We conducted a prospective analysis of examination and treatment results of 121 patients who were admitted to the Public Institution, Mechnikov Dnipropetrovsk Regional Clinical Hospital, Dnipro, Ukraine, from 25 May 2014, to 31 December 2017, and were successively enrolled in the study. Intracranial purulent-septic complications were diagnosed in 14 (11.6%) patients including eight cases of isolated meningoencephalitis, three cases of meningoencephalitis combined with ventriculitis, two cases of meningoencephalitis combined with ventriculitis and subdural empyema and one case of multiple brain abscesses. In most cases of combat-related craniocerebral wounds, infections are considered nosocomial and typically related to medical procedures and devices. In most cases, the effectiveness of first-line antibiotics was low, and it was often necessary to prescribe broad-spectrum ABT, including those related to secondline antibiotics and reserve drugs, according to the World Health Organisation classification. The use of initial de-escalation of empiric ABT with the broadest-spectrum drugs, mainly as a part of combination therapy for expected gram-positive and gramnegative aerobic and anaerobic infection pathogens, is recommended

Near-equatorial Pi2 and Pc3 waves observed by CHAMP and on SAMBA/MAGDAS stations

We have examined simultaneous ULF activity in the Pi2 and Pc3 bands at the near-equatorial magnetic stations in South America from SAMBA and MAGDAS arrays and low-orbiting CHAMP satellite during its passage over this meridional network. At the nighttime, both Pi2 and Pc3 waves in the upper ionosphere and on the ground are nearly of the same magnitude and in-phase. At the same time, the daytime Pc3 pulsations on the ground and in space are nearly out-of-phase. Comparison of observational results with the theoretical notions on the MHD wave interaction with the system ionosphere–atmosphere–ground suggests that nighttime low-latitude Pi2 and Pc3 wave signatures are produced by magnetospheric fast compressional mode. The daytime near-equatorial Pc3 waves still resist a quantative interpretation. These waves may be produced by a combination of two mechanisms: compressional mode leakage through the ionosphere, and by oscillatory ionospheric current spreading towards equatorial latitudes

Polymorphism of the LCT gene regulatory region in Turkicspeaking populations of the Altay-Sayan region (southern Siberia)

Retention of lactase activity in adulthood (lactase persistence) is one of the most important adaptive traits for human populations that consume fresh milk from domestic animals. At a molecular-genetic level, lactase persistence is determined by the presence of specific alleles of polymorphic sites in cis-regulatory elements of the LCT gene located on chromosome 2q21. Ascertainment of the molecular-genetic causes of lactase persistence has made this trait one of the most convenient for studying mechanisms of human population adaptation to environmental conditions. But the populations of many regions remain insufficiently investigated in relation to the genetic variability of the LCT loci. This paper presents the results of polymorphism analysis of loci, including the enhancer element for the LCT gene and its flanking regions, in two Turkic-speaking populations from southern Siberia, Altaian Kazakhs and Khakasses. It was found that the “European” allele LCT-13910T is the most characteristic of the Turkic-speaking populations from Altai-Sayan regions among all the polymorphic variants associated with lactase persistence. The expansion of the “European” allele LCT-13910T to the gene pool of the populations in southern Siberia could be related to migration waves of ancient herders form western Eurasia during the Bronze Age (in III – II millennium BC). A decrease of the LCT-13910T allele frequency and the total frequency of its carriers in the Turkic-speaking populations of southern Siberia in comparison with the majority of European populations and the Kazakhs from southern Central Asia can be attributed to: (1) a significant influence on the Altai- Sayan population’s gene pool by Eastern Eurasian populations, for which the LCT-13910T allele is rare; (2) a lesser adaptive significance of lactase persistence for south Siberian populations, compared to the populations of Europe. Rare and unique SNPs in the locus under consideration that were found in the Altaian Kazakhs (LCT-13895G > C and LCT-13927C > G) and Khakasses (LCT-14011C > T) potentially play a role in regulation of LCT gene expression, because they are located within the enhancer, regulating activity of its promoter

Statistical study of the effect of ULF fluctuations in the IMF on the cross polar cap potential drop for northward IMF

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95210/1/jgra21543.pd

Crack growth by surface diffusion in viscoelastic media

We discuss steady state crack growth in the spirit of a free boundary problem. It turns out that mode I and mode III situations are very different from each other: In particular, mode III exhibits a pronounced transition towards unstable crack growth at higher driving forces, and the behavior close to the Griffith point is determined entirely through crack surface dissipation, whereas in mode I the fracture energy is renormalized due to a remaining finite viscous dissipation. Intermediate mixed-mode scenarios allow steady state crack growth with higher velocities, leading to the conjecture that mode I cracks can be unstable with respect to a rotation of the crack front line