Isolation of cubic Si3P4 in the form of nanocrystals.

This article describes an approach for synthesizing silicon phosphide nanoparticles with a defective zinc blende structure under mild conditions through thermal annealing of hydrogenated silicon nanoparticles with red phosphorus. The synthesized Si3P4 nanoparticles were analyzed using FTIR, XRD, electron diffraction, EDX, TEM, Raman spectroscopy, X-ray fluorescence spectrometry, and UV-vis spectrophotometry. For the isolated cubic Si3P4 phase, a cell parameter of a = 5.04 Å was determined, and the bandgap was estimated to be equal to 1.25 eV. Because of the nanoscale dimensions of the obtained Si3P4 nanoparticles, the product may exhibit several exceptional properties as a precursor for diffusion doping of wafers and as anode material for Li-ion batteries. A similar method with a hydrogenation step offers the possibility to obtain other compounds, such as silicon selenides, arsenides, and sulfides.

Effect of 10 MeV electron irradiation on the electrical properties of bulk α-In2Se3 crystals.

In this work, the effect of 10 MeV electron irradiation on the structure and electrical properties of bulk α-In2Se3 crystals is studied by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray microanalysis, atomic-force microscopy, and Raman spectroscopy methods. Droplets of 200-500 nm in size were detected on the bulk α-In2Se3 crystal surface. The droplets can be formations with the γ-In2Se3 crystalline phase. The current-voltage characteristics measured by conductive atomic-force microscopy are different on and outside the droplets after electron irradiation. On the droplets, slightly better conductive properties were detected after irradiation with the electron fluence of 1015 cm-2. It is found that local resistance increases significantly for both on and outside the droplets after irradiation with the electron fluence of 1017 cm-2. Our study shows that electron irradiation can contribute to the disappearance of ferroelectric domains in the bulk α-In2Se3 crystals. Also, the distribution of surface potentials measured by Kelvin probe force microscopy becomes more uniform after electron irradiation. The results obtained in the work allow us to calculate the operating time of the device containing α-In2Se3 under conditions of long-term electron irradiation with high-energy electrons. The study shows that α-In2Se3 is a very promising material for applications in the aerospace and nuclear industries.

Mechanical and Structural Characterization of Laser-Cladded Medium-Entropy FeNiCr-B4C Coatings.

Equiatomic medium-entropy alloy (MEA) FeNiCr-B4C (0, 1, and 3 wt.% B4C) coatings were deposited onto an AISI 1040 steel substrate using pulsed laser cladding. Based on an SEM microstructural analysis, it was found that the cross-sections of all the obtained specimens were characterized by an average coating thickness of 400 ± 20 µm, a sufficiently narrow (100 ± 20 µm) "coating-substrate" transition zone, and the presence of a small number of defects, including cracks and pores. An XRD analysis showed that the formed coatings consisted of a single face-centered cubic (FCC) γ-phase and the space group Fm-3m, regardless of the B4C content. However, additional TEM analysis of the FeNiCr coating with 3 wt.% B4C revealed a two-phase FCC structure consisting of grains (FCC-1 phase, Fm-3m) up to 1 µm in size and banded interlayers (FCC-2 phase, Fm-3m) between the grains. The grains were clean with a low density of dislocations. Raman spectroscopy confirmed the presence of B4C carbides inside the FeNiCr (1 and 3 wt.% B4C) coatings, as evidenced by detected peaks corresponding to amorphous carbon and peaks indicating the stretching of C-B-C chains. The mechanical characterization of the FeNiCr-B4C coatings specified that additions of 1 and 3 wt.% B4C resulted in a notable increase in microhardness of 16% and 38%, respectively, with a slight decrease in ductility of 4% and 10%, respectively, compared to the B4C-free FeNiCr coating. Thus, the B4C addition can be considered a promising method for strengthening laser-cladded MEA FeNiCr-B4C coatings.

The Effect of Three Complexes of Iodine with Amino Acids on Gene Expression of Model Antibiotic Resistant Microorganisms Escherichia coli ATCC BAA-196 and Staphylococcus aureus ATCC BAA-39.

1. BACKGROUND: Iodine is a broad-spectrum antimicrobial disinfectant for topical application. Recent studies have shown promising results on the applicability of an iodine-containing complex, FS-1, against antibiotic-resistant pathogens. It was hypothesized that the antimicrobial activity of iodine-containing complexes may be modulated by the organic moiety of the complex, i.e., amino acids. 2. METHODS: Gene regulation and metabolic alterations were studied in two model multidrug-resistant microorganisms, Staphylococcus aureus ATCC BAA-39, and Escherichia coli ATCC BAA-196, treated with three complexes containing iodine and three different amino acids: glycine, L-alanine, and L-isoleucine. The bacterial cultures were exposed to sub-lethal concentrations of the complexes in the lagging and logarithmic growth phases. Gene regulation was studied by total RNA sequencing and differential gene expression analysis. 3. RESULTS: The central metabolism of the treated bacteria was affected. An analysis of the regulation of genes involved in stress responses suggested the disruption of cell wall integrity, DNA damage, and oxidative stress in the treated bacteria. 4. CONCLUSIONS: Previous studies showed that the application of iodine-containing complexes, such as FS-1, serves as a supplement to common antibiotics and can be a promising way to combat antibiotic-resistant pathogens. Current results shed light on possible mechanisms of this action by disrupting the cell wall barriers and imposing oxidative stress. It was also found that the effect of the complexes on metabolic pathways varied in the tested microorganisms depending on the organic moiety of the complexes and the growth phase when the complexes had been applied.

Analysis of Whole-Genome Sequences of Pathogenic Gram-Positive and Gram-Negative Isolates from the Same Hospital Environment to Investigate Common Evolutionary Trends Associated with Horizontal Gene Exchange, Mutations and DNA Methylation Patterning.

Hospital-acquired infections are a generally recognized problem for healthcare professionals. Clinical variants of Gram-negative and Gram-positive pathogens are characterized with enhanced antibiotic resistance and virulence due to mutations and the horizontal acquisition of respective genetic determinants. In this study, two Escherichia coli, two Klebsiella pneumoniae, three Pseudomonas aeruginosa, two Staphylococcus aureus, one Staphylococcus epidermidis and one Streptococcus pneumoniae showing broad spectra of antibiotic resistance were isolated from patients suffering from nosocomial infections in a local hospital in Almaty, Kazakhstan. The aim of the study was to compare general and species-specific pathways of the development of virulence and antibiotic resistance through opportunistic pathogens causing hospital-acquired infections. The whole-genome PacBio sequencing of the isolates allowed for the genotyping and identification of antibiotic resistance and virulence genetic determinants located in the chromosomes, plasmids and genomic islands. It was concluded that long-read sequencing is a useful tool for monitoring the epidemiological situation in hospitals. Marker antibiotic resistance mutations common for different microorganisms were identified, which were acquired due to antibiotic-selective pressure in the same clinical environment. The genotyping and identification of strain-specific DNA methylation motifs were found to be promising in estimating the risks associated with hospital infection outbreaks and monitoring the distribution and evolution of nosocomial pathogens.

Recrystallization of Si Nanoparticles in Presence of Chalcogens: Improved Electrical and Optical Properties.

Nanocrystals of Si doped with S, Se and Te were synthesized by annealing them in chalcogen vapors in a vacuum at a high temperature range from 800 to 850 °C. The influence of the dopant on the structure and morphology of the particles and their optical and electrical properties was studied. In the case of all three chalcogens, the recrystallization of Si was observed, and XRD peaks characteristic of noncubic Si phases were found by means of electronic diffraction for Si doped with S and Se. Moreover, in presence of S and Te, crystalline rods with six-sided and four-sided cross-sections, respectively, were formed, their length reaching hundreds of µm. Samples with sulfur and selenium showed high conductivity compared to the undoped material.

Whole genome sequence data of Stenotrophomonas maltophilia SCAID WND1-2022 (370).

The whole genome sequence of a hospital infection agent, Stenotrophomonas maltophilia SCAID WND1-2022 (370), is reported. Raw PacBio generated reads and the genome sequence were deposited at NCBI under BioProject PRJNA754843. The genome comprises two replicons: 4,880,425 bp long chromosome comprising 4524 proteins and functional RNA coding genes and 38,606 bp long plasmid containing 40 CDS. Both replicons were methylated at third cytosine residues of ACCTC motifs. The taxonomic provenance of SCAID WND1-2022 (370) was determined by calculating sequence similarity to the reference genomes at NCBI that showed the highest 97.35% identity to S. maltophilia ISMMS4. Many antibiotic resistance and virulence genes were identified on the chromosome of S. maltophilia SCAID WND1-2022 (370), which include multiple efflux pumps, beta-lactamases, and genes involved in biofilm formation. The plasmid sequence was dissimilar to any known plasmid and seemingly was acquired from a distant microorganism. Plasmid-born genes possibly contributed to the virulence of the pathogens, but not to its drug resistance.

Modern Aspects of Burn Injury Immunopathogenesis and Prognostic Immunobiochemical Markers (Mini-Review).

Burn injuries are among the most common peacetime injuries, with mortality ranging from 2.3% to 3.6%. At the same time, 85-90% of patients with burns are people of working age and children. Burn injury leads to metabolic disorders and systemic inflammatory response, inefficient energy consumption, and other physiological changes that can lead to dysfunction of organs and systems. The most formidable complication of burn injuries is sepsis mediated by multiple organ failure, the most common cause of poor prognosis in patients and has specific differences in these injuries. The purpose of this article was to dwell in detail on the most promising immunobiochemical markers of sepsis in the format of a mini-review, based on the main aspects of the immunopathogenesis of this complication. The pathogenesis of a burn injury and any general pathological process is based on an inflammatory reaction and large-scale changes in the skin and mucous membranes. This review is devoted to the progress in understanding the main aspects of the immunopathogenesis of burn lesions and the features of post-burn immune dysfunction, manifested by disorders in the innate and adaptive immunity systems. Attention is focused on the role in the immunopathogenesis of the development of systemic and local disorders in burn injury. Characterization of primary immunobiochemical markers of burn injury (cytokines, growth factors, C-reactive protein, procalcitonin, presepsin, matrix metalloproteinases, reactive oxygen species, nitric oxide, hemostasis parameters) is presented. The problem of treating burn lesions is associated with constant monitoring of the condition of patients and regular monitoring of specific immunobiochemical markers predicting sepsis for the timely initiation of a specific therapy.

Molecular Targets of Brown Algae Phlorotannins for the Therapy of Inflammatory Processes of Various Origins.

Inflammatory reactions are part of a complex biological response that plays a vital role in the appearance of various stimuli resulting from tissue and cell damage, the invasion of pathogenic bacteria, and the formation of the subsequent adaptive immune response. The production of many triggers and mediators of inflammation, which are inducers of pro-inflammatory factors, is controlled by numerous differentiation programs, through which inflammation is resolved and tissue homeostasis is restored. However, prolonged inflammatory responses or dysregulation of pro-inflammatory mechanisms can lead to chronic inflammation. Modern advances in biotechnology have made it possible to characterize the anti-inflammatory activity of phlorotannins, polyphenolic compounds from brown seaweed, and the mechanisms by which they modulate the inflammatory response. The purpose of this review is to analyze and summarize the results of numerous experimental in vitro and in vivo studies, illustrating the regulatory mechanisms of these compounds, which have a wide range of biological effects on the body. The results of these studies and the need for further research are discussed.

Complete Genome Sequences of Gram-Positive Opportunistic Pathogens Isolated from Hospitals in Almaty, Kazakhstan.

The appearance of drug-resistant pathogens reduces the therapeutic applicability of antibiotics and increases the rate of hospital infections among patients. Complete genome sequences of four Gram-positive clinical isolates of Streptococcus and Staphylococcus were obtained and analyzed to serve as model microorganisms for further studies on drug-induced antibiotic resistance reversion.

The Role of Cumulative LDL Cholesterol in Cardiovascular Disease Development in Patients with Familial Hypercholesterolemia.

In patients with familial hypercholesterolemia (FH) the exposure of very high LDL-C concentration and cumulative LDL-C level (cum LDL-C) can play a significant role in the prognosis. OBJECTIVE: to analyze the contribution of "cum LDL-C for all life" and the index "cum LDL-C/age" to the development of coronary heart disease (CHD), myocardial infarction (MI), and a combined end point: MI, stroke, unstable angina in FH patients. METHODS: 188 patients (mean age 49.2 years, males 45.7%) with FH were examined (Dutch Lipid Clinic Criteria). We had evaluated cumulative LDL-C and index "cum DL-C/age" along with other classical risk factors. Cum LDL-C was calculated as LDL-Cmax × (age at initiating of hypolipidemic therapy) + LDL-C at inclusion age at initiation/correction therapy). Cumulative LDL-C and "cum LDL-C/age" were calculated as the ratio cum LDL-C to age. The follow-up period was 5.4 (from 3 to 10) years. RESULTS: The index "cum LDL-C/age" was higher in patients with CHD 58.7 ± 10.4 mmol/L/years vs. 40.1 ± 11.7 mmol/L/years in patients without CHD (p < 0.001). According to our data based on the results of the logistic regression analysis in patients with FH, cumulative LDL-C and the cumulative index "cum LDL-C/age" played a strong predictive role in the development of CHD in FH patients; it was greater than the role of TC and LDL-C concentrations. We present ROC curves for CHD, MI and combined end point in FH patients, and a prognostic scale for CHD development, which is based on classical cardiovascular risk factors. CONCLUSION: cumulative LDL-C level plays an important role in the development of CHD in FH patients.

Antiparasitic Effects of Sulfated Polysaccharides from Marine Hydrobionts.

This review presents materials characterizing sulfated polysaccharides (SPS) of marine hydrobionts (algae and invertebrates) as potential means for the prevention and treatment of protozoa and helminthiasis. The authors have summarized the literature on the pathogenetic targets of protozoa on the host cells and on the antiparasitic potential of polysaccharides from red, brown and green algae as well as certain marine invertebrates. Information about the mechanisms of action of these unique compounds in diseases caused by protozoa has also been summarized. SPS is distinguished by high antiparasitic activity, good solubility and an almost complete absence of toxicity. In the long term, this allows for the consideration of these compounds as effective and attractive candidates on which to base drugs, biologically active food additives and functional food products with antiparasitic activity.

Complete Genome Sequences of Gram-Negative Opportunistic Pathogens Isolated in Hospitals in Almaty, Kazakhstan.

The problem of nosocomial infections is growing due to the introduction of new treatment regimens involving immunosuppressive drugs. The genomes of seven Gram-negative clinical isolates of Escherichia, Klebsiella, and Pseudomonas were sequenced and analyzed in this study to serve as model microorganisms to study drug-induced antibiotic resistance reversion.

Nanomechanical and Nanotribological Properties of Nanostructured Coatings of Tantalum and Its Compounds on Steel Substrates.

The present paper addresses the problem of identification of microstructural, nanomechanical, and tribological properties of thin films of tantalum (Ta) and its compounds deposited on stainless steel substrates by direct current magnetron sputtering. The compositions of the obtained nanostructured films were determined by energy dispersive spectroscopy. Surface morphology was investigated using atomic force microscopy (AFM). The coatings were found to be homogeneous and have low roughness values (<10 nm). The values of microhardness and elastic modulus were obtained by means of nanoindentation. Elastic modulus values for all the coatings remained unchanged with different atomic percentage of tantalum in the films. The values of microhardness of the tantalum films were increased after incorporation of the oxygen and nitrogen atoms into the crystal lattice of the coatings. The coefficient of friction, CoF, was determined by the AFM method in the "sliding" and "plowing" modes. Deposition of the coatings on the substrates led to a decrease of CoF for the coating-substrate system compared to the substrates; thus, the final product utilizing such a coating will presumably have a longer service life. The tantalum nitride films were characterized by the smallest values of CoF and specific volumetric wear.

Transcriptomics and methylomics study on the effect of iodine-containing drug FS-1 on Escherichia coli ATCC BAA-196.

Aim: Promising results on application of iodine-containing nano-micelles, FS-1, against antibiotic-resistant Escherichia coli was demonstrated. Materials & methods: RNA sequencing for transcriptomics and the complete genome sequencing by SMRT PacBio were followed by genome assembly and methylomics. Results & conclusion: FS-1-treated E. coli showed an increased susceptibility to antibiotics ampicillin and gentamicin. Cultivation with FS-1 caused gene expression alterations toward anaerobic respiration, increased anabolism and inhibition of many nutrient uptake systems. Main targets of iodine-containing particles were cell membrane structures causing oxidative, osmotic and acidic stresses. Identification of methylated nucleotides showed an altered pattern in the FS-1-treated culture. Possible role of transcriptional and epigenetic modifications in the observed increase in susceptibility to gentamicin and ampicillin were discussed.

Lay abstract New approaches of combatting drug-resistant infections are in demand as the development of new antibiotics is in a deep crisis. This study was set out to investigate molecular mechanisms of action of new iodine-containing nano-micelle drug FS-1, which potentially may improve the antibiotic therapy of drug-resistant infections. Iodine is one of the oldest antimicrobials and until now there were no reports on development of resistance to iodine. Recent studies showed promising results on application of iodine-containing nano-micelles against antibiotic-resistant pathogens as a supplement to antibiotic therapy. The mechanisms of action, however, remain unclear. The collection strain Escherichia coli ATCC BAA-196 showing an extended spectrum of resistance to ßß-lactam and aminoglycoside antibiotics was used in this study as a model organism. Antibiotic resistance patterns, whole genomes and total RNA sequences of the FS-1-treated (FS) and negative control (NC) variants of E. coli BAA-196 were obtained and analyzed. FS culture showed an increased susceptibility to antibiotics associated with profound gene expression alterations switching the bacterial metabolism to anaerobic respiration, increased anabolism, osmotic stress response and inhibition of many nutrient uptake systems. Nucleotide methylation pattern were identified in FS and NC cultures. While the numbers of methylated sites in both genomes remained similar, some peculiar alterations were observed in their distribution along chromosomal and plasmid sequences.

Properties of CrSi2 Layers Obtained by Rapid Heat Treatment of Cr Film on Silicon.

The changes in the morphology and the electrophysical properties of the Cr/n-Si (111) structure depending on the rapid thermal treatment were considered in this study. The chromium films of about 30 nm thickness were deposited via magnetron sputtering. The rapid thermal treatment was performed by the irradiation of the substrate's back side with the incoherent light flux of the quartz halogen lamps in nitrogen medium up to 200-550 °C. The surface morphology was investigated, including the grain size, the roughness parameters and the specific surface energy using atomic force microscopy. The resistivity value of the chromium films on silicon was determined by means of the four-probe method. It was established that at the temperatures of the rapid thermal treatment up to 350 °Ð¡ one can observe re-crystallization of the chromium films with preservation of the fine grain morphology of the surface, accompanied by a reduction in the grain sizes, specific surface energy and the value of specific resistivity. At the temperatures of the rapid thermal treatment from 400 to 550 °Ð¡ there originates the diffusion synthesis of the chromium disilicide CrSi2 with the wave-like surface morphology, followed by an increase in the grain sizes, roughness parameters, the specific surface energy and the specific resistivity value.

The Potency of Seaweed Sulfated Polysaccharides for the Correction of Hemostasis Disorders in COVID-19.

Hemostasis disorders play an important role in the pathogenesis, clinical manifestations, and outcome of COVID-19. First of all, the hemostasis system suffers due to a complicated and severe course of COVID-19. A significant number of COVID-19 patients develop signs of hypercoagulability, thrombocytopenia, and hyperfibrinolysis. Patients with severe COVID-19 have a tendency toward thrombotic complications in the venous and arterial systems, which is the leading cause of death in this disease. Despite the success achieved in the treatment of SARS-CoV-2, the search for new effective anticoagulants, thrombolytics, and fibrinolytics, as well as their optimal dose strategies, continues to be relevant. The wide therapeutic potential of seaweed sulfated polysaccharides (PSs), including anticoagulant, thrombolytic, and fibrinolytic activities, opens up new possibilities for their study in experimental and clinical trials. These natural compounds can be important complementary drugs for the recovery from hemostasis disorders due to their natural origin, safety, and low cost compared to synthetic drugs. In this review, the authors analyze possible pathophysiological mechanisms involved in the hemostasis disorders observed in the pathological progression of COVID-19, and also focus the attention of researchers on seaweed PSs as potential drugs aimed to correction these disorders in COVID-19 patients. Modern literature data on the anticoagulant, antithrombotic, and fibrinolytic activities of seaweed PSs are presented, depending on their structural features (content and position of sulfate groups on the main chain of PSs, molecular weight, monosaccharide composition and type of glycosidic bonds, the degree of PS chain branching, etc.). The mechanisms of PS action on the hemostasis system and the issues of oral bioavailability of PSs, important for their clinical use as oral anticoagulant and antithrombotic agents, are considered. The combination of the anticoagulant, thrombolytic, and fibrinolytic properties, along with low toxicity and relative cheapness of production, open up prospects for the clinical use of PSs as alternative sources of new anticoagulant and antithrombotic compounds. However, further investigation and clinical trials are needed to confirm their efficacy.

Monitoring of pathogenic Borrelia burgdorferi sensu lato in the Almaty oblast, Kazakhstan.

Lyme borreliosis (LB) is one of the most common vector-borne diseases transmitted by ticks. It is caused by the Borrelia burgdorferi sensu lato (s.l.) genospecies. The Almaty oblast of Kazakhstan is considered endemic for LB. Nevertheless, there are significant gaps in the tick surveillance for LB agents in the region. We evaluated B. burgdorferi s.l. prevalence in 413 ixodid ticks collected from bitten people and the seroprevalence of antibodies to B. burgdorferi s.l. in 589 residents of the Almaty oblast, Kazakhstan. All samples were collected between 2018 and 2020. Borrelia burgdorferi s.l. DNA was detected in 24 % (9/38) of I. persulcatus ticks that attacked humans in the city of Almaty and the Talgar and Karasay districts. Multilocus sequence typing identified two novel B. afzelii sequence types in I. persulcatus. The seroprevalence of IgG antibodies against B. burgdorferi s.l. in the analyzed population was detected to be 5.8 %. The obtained results confirm active circulation of B. burgdorferi s.l. in the Almaty oblast of Kazakhstan and raise concern regarding LB preventive measures in the region.

Structure and Properties of ZrON Coatings Synthesized by Cathodic Arc Evaporation.

The transition metal oxynitrides are a coating material with decorative features due to their adjustable color and good mechanical properties. The purpose of the research was to study the effect of the relative oxygen concentration O2(x) = O2/(N2 + O2) in particular on adhesion, but also on the color, structural and mechanical properties of ZrON coatings synthesized by cathodic arc evaporation on HS6-5-2 steel substrates. The surface morphology, phase and chemical composition and mechanical properties were determined using scanning electron microscopy, X-ray diffraction, wavelength dispersive X-ray spectroscopy, nanoindentation and scratch test. It was found that color of the coatings changed from light yellow for ZrN first to gold and then to graphite for Zr-O phase with increase of oxygen concentration. X-ray diffraction patterns showed that the phase separation of ZrN and ZrO2 occurred for about 35 at.% of oxygen in the coating. Increase in oxygen concentration in the coatings led to decrease in crystallite size from about 20 nm for ZrN to about 5 nm for coatings with about 35 at.% of oxygen and about 25 at.% of nitrogen. An increase in hardness from about 26 GPa for ZrN to about 30 GPa for coating with small concentration of oxygen (about 9 at.%) and then decrease to about 15 GPa was observed. Adhesion of Zr-O-N coatings demonstrated strong dependence on oxygen concentration. Critical load for ZrN is about 80 N and decreases with oxygen concentration increase to about 30 N for ZrO2.

Antiviral Effects of Polyphenols from Marine Algae.

The disease-preventive and medicinal properties of plant polyphenolic compounds have long been known. As active ingredients, they are used to prevent and treat many noncommunicable diseases. In recent decades, marine macroalgae have attracted the attention of biotechnologists and pharmacologists as a promising and almost inexhaustible source of polyphenols. This heterogeneous group of compounds contains many biopolymers with unique structure and biological properties that exhibit high anti-infective activity. In the present review, the authors focus on the antiviral potential of polyphenolic compounds (phlorotannins) from marine algae and consider the mechanisms of their action as well as other biological properties of these compounds that have effects on the progress and outcome of viral infections. Effective nutraceuticals, to be potentially developed on the basis of algal polyphenols, can also be used in the complex therapy of viral diseases. It is necessary to extend in vivo studies on laboratory animals, which subsequently will allow proceeding to clinical tests. Polyphenolic compounds have a great potential as active ingredients to be used for the creation of new antiviral pharmaceutical substances.