Effects of cluster diffusion on the island density and size distribution in submonolayer island growth

The effects of cluster diffusion on the submonolayer island density and island-size distribution are studied for the case of irreversible growth of compact islands on a 2D substrate. In our model, we assume instantaneous coalescence of circular islands, while the cluster mobility is assumed to exhibit power-law decay as a function of island-size with exponent mu. Results are presented for mu = 1/2, 1, and 3/2 corresponding to cluster diffusion via Brownian motion, correlated evaporation-condensation, and edge-diffusion respectively, as well as for higher values including mu = 2,3, and 6. We also compare our results with those obtained in the limit of no cluster mobility corresponding to mu = infinity. In agreement with theoretical predictions of power-law behavior of the island-size distribution (ISD) for mu < 1, for mu = 1/2 we find Ns({\theta}) ~ s^{-\tau} (where Ns({\theta}) is the number of islands of size s at coverage {\theta}) up to a cross-over island-size S_c. However, the value of {\tau} obtained in our simulations is higher than the mean-field (MF) prediction {\tau} = (3 - mu)/2. Similarly, the value of the exponent {\zeta} corresponding to the dependence of S_c on the average island-size S (e.g. S_c ~ S^{\zeta}) is also significantly higher than the MF prediction {\zeta} = 2/(mu+1). A generalized scaling form for the ISD is also proposed for mu < 1, and using this form excellent scaling is found for mu = 1/2. However, for finite mu >= 1 neither the generalized scaling form nor the standard scaling form Ns({\theta}) = {\theta} /S^2 f(s/S) lead to scaling of the entire ISD for finite values of the ratio R of the monomer diffusion rate to deposition flux. Instead, the scaled ISD becomes more sharply peaked with increasing R and coverage. This is in contrast to models of epitaxial growth with limited cluster mobility for which good scaling occurs over a wide range of coverages.Comment: 12 pages, submitted to Physical Review

Some Aspects of Oxidation-Reduction Reactions under Carbon-Bearing Flux Welding

The authors have completed thermodynamic calculations of oxidation-reduction processes under submerged arc welding with application of carbon containing additive. The calculations have shown that carbon, due to its high reducing properties under Т=1950-2200 K, introduced into the system can significantly decrease the amount of non-metallic inclusions in the weld metal and so improve its mechanical properties

Comparison of the Endoscopic Picture in Case of Complications of the upper Gastrointestinal Tract Caused by the Use of Antithrombotic Agents and Non-Steroidal Anti-Inflammatory Drugs

Intaking antithrombotic funds (ATA) and non-steroidal anti-inflammatory drugs (NSAIDs) is one of the most frequent causes of pathology in gastrointestinal (GI) tract.The purpose of the study: comparison of pathological changes of the mucous membrane in the upper GI tract, that occur against the background of ATA and NSAIDs admission.Material and methods. Endoscopic data of two groups of patients taking ATA and NSAIDS have been compared. The first group of 448 patients from the 10th Gastrointestinal Department in N.N. Burdenko Main Military Clinical Hospital was on record from 2013 to 2017. The patients had erosive ulcerous changes of gastrointestinal mucosa, occurred against the background of the ATA admission. The second group comprised 6431 patients with rheumatic diseases. They were hospitalized in the clinic of V.A. Nasonova Research Institute of Rheumatology in the period from 2007 to 2016 and took NSAIDs regularly.Results. Duodenal and gastric ulcer changes in gastric mucosa and duodenal ulcers were identified in 168 (37.5 %) patients taking ATA and in 1691 (26.3 %) patient treated with NSAIDS. Structure of pathology varied. So, against the background of ATA and NSAIDS admission, the number of acute gastric ulceration amounted to 6.5 % and 15.5 % (p &lt; 0.001); acute ulcers duodenal was 2.9 % and 4.9 %; combined ulcerative lesions of gastric and duodenal was 2.9 % and 2.0 %; multiple erosions of gastroduodenal mucosa were 52.4 % and 15.7 % (p &lt; 0.001); single erosion was 35. 1% and 61.6 %. The factor of ulcer history and age ≥ 65 years old increased significantly the risk of duodenal and gastric ulcer changes in patients taking ATA and NSAIDs: OR 5.182 (95% CI 2.701–9.942) and 3.24 (95% CI 2.19–5.34), 4.537 (95% CI 2.036–10.11) and 2.016 (95% CI 1.230–2.917) respectively. Intaking of proton pump inhibitor (PPI) reduced significantly the risk of complications for both ATA and NSAIDs: OR 0.329 (95% CI 0.199–0.546) and 0.317 (95% CI 0.210–0.428) respectively.Conclusion. The structure of pathology of mucous in the upper gastrointestinal tract that arose against the backdrop of ATA and NSAIDs admission is different. The first is characterized by a multiple erosion, while the second one has single acute distal gastric ulcers. The ulcerative history and advanced age of patients increase significantly the risk of complications concerning the gastroduodenal mucosa when using ATA and NSAIDs. PPI is the effective means of preventing this pathology

Efficient laser pumping of a Co:MgF2 crystal by radiation with the wavelength 1.3 μm

A Co:MgF2 crystal laser was pumped with radiation (λ = 1.35 μm) from a neodymium glass laser. This resulted in generation of radiation of 1.6 J energy with a quantum efficiency of 67%. The Co:MgF2 crystal could thus be used for efficient conversion of λ = 1.3 μm laser beams, such as those from iodine photodissociation and chemical oxygen-iodine lasers

Perspectives of using Illumina MiSeq for identification of arbuscular mycorrhizal fungi

Arbuscular mycorrhiza fungi (AMF) form one of the most common symbiosis with the majority of land plants. AMF supply the plant with various mineral elements, primarily phosphorus, and improve the water supply. The search for the most effective AMF strains for symbiosis and the creation of microbial preparations on that basis is an important task for modern biology. Owing to the difficulties of cultivation without a host plant and their high genetic polymorphism, identifying AMF is very difficult. The high number of cryptic species often also makes morphological identification unreliable. Recent years have seen growth in the number of AMF biodiversity studies performed by modern NGS-based methods, Illumina MiSeq in particular. Currently, there are still many questions that remain for the identification of AМF. The most important are whether conservative or variable sequences should be used to select a marker for barcoding and whether universal primers or those specific to AMF should be used. In our work, we have successfully used universal primers ITS3 and ITS4 for the sequencing in Illumina MiSeq of the 5.8S rDNA – ITS2 region of the 35S rRNA genes, which contain both a conservative and variable regions. The molecular genetic approach for AMF identification was quite effective and allowed us to reliably identify eight of nine isolates to the species level: five isolates of Rhizophagus irregularis, and one isolate of R. invermaius, Paraglomus laccatum, and Claroideoglomus etunicatum, respectively. For all five R. irregularis isolates high variability in the ITS region and the absence of ecotopic-related molecular characters in the ITS2 region were demonstrated. The NCBI data is still insufficient for accurate AMF identification of Acaulospora sp. isolates from the genus to the species level

Tunka Advanced Instrument for cosmic rays and Gamma Astronomy

The paper is a script of a lecture given at the ISAPP-Baikal summer school in 2018. The lecture gives an overview of the Tunka Advanced Instrument for cosmic rays and Gamma Astronomy (TAIGA) facility including historical introduction, description of existing and future setups, and outreach and open data activities.Comment: Lectures given at the ISAPP-Baikal Summer School 2018: Exploring the Universe through multiple messengers, 12-21 July 2018, Bol'shie Koty, Russi

Fungus Metarhizium robertsii and neurotoxic insecticide affect gut immunity and microbiota in Colorado potato beetles

Fungal infections and toxicoses caused by insecticides may alter microbial communities and immune responses in the insect gut. We investigated the effects of Metarhizium robertsii fungus and avermectins on the midgut physiology of Colorado potato beetle larvae. We analyzed changes in the bacterial community, immunity- and stress-related gene expression, reactive oxygen species (ROS) production, and detoxification enzyme activity in response to topical infection with the M. robertsii fungus, oral administration of avermectins, and a combination of the two treatments. Avermectin treatment led to a reduction in microbiota diversity and an enhancement in the abundance of enterobacteria, and these changes were followed by the downregulation of Stat and Hsp90, upregulation of transcription factors for the Toll and IMD pathways and activation of detoxification enzymes. Fungal infection also led to a decrease in microbiota diversity, although the changes in community structure were not significant, except for the enhancement of Serratia. Fungal infection decreased the production of ROS but did not affect the gene expression of the immune pathways. In the combined treatment, fungal infection inhibited the activation of detoxification enzymes and prevented the downregulation of the JAK-STAT pathway caused by avermectins. The results of this study suggest that fungal infection modulates physiological responses to avermectins and that fungal infection may increase avermectin toxicosis by blocking detoxification enzymes in the gut