α-Fe2O3@Pt heterostructure particles to enable sonodynamic therapy with self-supplied O2 and imaging-guidance

Sonodynamic therapy (SDT), presenting spatial and temporal control of ROS generation triggered by ultrasound field, has attracted considerable attention in tumor treatment. However, its therapeutic efficacy is severely hindered by the intrinsic hypoxia of solid tumor and the lack of smart design in material band structure. Here in study, fine α-Fe2O3 nanoparticles armored with Pt nanocrystals (α-Fe2O3@Pt) was investigated as an alternative SDT agent with ingenious bandgap and structural design. The Schottky barrier, due to its unique heterostructure, suppresses the recombination of sono-induced electrons and holes, enabling superior ROS generation. More importantly, the composite nanoparticles may effectively trigger a reoxygenation phenomenon to supply sufficient content of oxygen, favoring the ROS induction under the hypoxic condition and its extra role played for ultrasound imaging. In consequence, α-Fe2O3@Pt appears to enable effective tumor inhibition with imaging guidance, both in vitro and in vivo. This study has therefore demonstrated a highly potential platform for ultrasound-driven tumor theranostic, which may spark a series of further explorations in therapeutic systems with more rational material design. Graphical Abstract

FAUNAL AND ECOLOGICAL FEATURES OF BLACKFLIES IN STATE BUDGETARY INSTITUTION SPORTS SCHOOL OF THE OLYMPIC RESERVE FOR EQUESTRIAN SPORTS, KALUGA

The article describes the faunal and ecological features of two species of blackflies common on the territory of the SBI "Sports School of the Olympic Reserve for Equestrian Sports" in Kaluga: Wilhelmia equina (Linnaeus, 1758) and Odagmia ornata (Meigen, 1818), which can cause simuliidotoxicosis of animals. The studied species are very widespread. Species Wilhelmia equina: their habitat is in rivers of medium and small sizes, sometimes in streams, the flow rate of which is 0.25–0.6 m/s. Blackflies in preimaginal stages settle on aquatic vegetation and underwater objects. The preimaginal stage develops at a water temperature of 2–23 oC with content of oxygen dissolved in water of 51–88%. On average, 2–3 generations are recorded per year. The adults of the first generation fly out in late May – early June, the second generation in late July – early August and the third generation in mid September. Odagmia ornata: it lives in various water bodies from small streams to large rivers. Larvae and pupae inhabit vegetation in water bodies and various objects. The species is unpretentious to water temperature and develops at temperatures from 4 to 21 oC and water flow rate 0.3–0.9 m/s with the required content of oxygen dissolved in water 42–82%. Three generations are recorded per year. The emergence and pupation of the first generation of adults is observed in early and mid-May, when the water temperature reaches 8–10 oС, and the second generation in July when the water temperature is from 11 to 22 oС. The third generation is observed in late August – early September, when the water temperature is 16–19 oC. It is considered an active blood-sucking insect for domestic animals.

Measuring the content of oxygen dissolved in a freshwater reservoir

For the life of fish and other aquatic animals, the oxygen dissolved in water is particularly important. Oxygen partially penetrates into water from the atmosphere, partially released in the reservoir itself as a result of the livelihoods of plant organisms. By means of chlorophyll, green plants extracted from carbon dioxide needed to construct a living matter of carbon, allocating oxygen in the surrounding space. This process of photosynthesis proceeds due to the energy of sunlight only in the light time of day. The penetration of oxygen in the atmosphere contributes to wind, flow, precipitation, sharp changes in temperature and other reasons that increase the mixing of water layers. In reservoirs, strongly contaminated organic substances, the water in addition to the rich salts of sulfuric acid (sulfates) may appear poisonous for fish and other aqueous animals gaz – hydrogen sulfide. It occurs only in the absence of oxygen with the participation of special bacteria. Carbon dioxide is accumulated as a result of breathing aquatic organisms, and most importantly - as a result of oxidation of organic matter. Therefore, the excess of carbon dioxide indicates a significant contamination of reservoirs by organic substances. In itself, the increase in water oxidation is safe for fish, and even useful to the known limits, since it usually increases the productivity of reservoirs. Organic substances that are formed in the reservoir itself, or industries from fields from fields, farmsteads, or stand out by birds, animals, human, contain some elements and compounds necessary for the development of all living creatures. Among such elements are primarily nitrogen and phosphorus. The abundance of organic substances containing these elements provides for the development of aquatic animals and plants. But when organic substances accumulate too much, then the oxygen regime of the reservoir deteriorates sharply until the conditions of the order. Classic methods and controls of biota parameters of fresh reservoirs have a row of substantial defects to that belong: systematic uncharacter of control of informatively important parameters; subzero exactness of parameters control; large volume of hand operations; necessity of knowledge of mathematical bases of method; bad interpretation of results; need to use support staff. The shortcomings of known methods can be corrected with an automated way of obtaining and processing the informative parameters of fresh water biota. A structural scheme of the process of obtaining the selected parameters of the biota and the preferential algorithm of their processing have been developed. It is shown that the most convenient for collecting mass material about the content of dissolved oxygen in the reservoir is the optical method. Comparison of synchronous measurements by optical and electrochemical sensors showed a significant underestimation of the dissolved oxygen content by an electrochemical sensor compared to the optical one. The optical method of measuring the content of oxygen dissolved in water is based on finding the time and intensity of fluorescence of the sensitive membrane by empirical ratio. Molecules of dissolved oxygen reduce the time and the intensity of membrane fluorescence, created from carefully selected chemical elements. An absolute concentration can be determined after linearization and thermocompensation, which is performed with the help of a built-in water temperature sensor.

Effect of Oxygen Content on Microstructure and Tensile Properties of a 22Cr-5Al ODS Steel

The high tensile strength and irradiation resistance of oxide dispersion strengthened (ODS) ferritic steels is attributed to the ultrafine and dispersed oxides within the matrix. The high content of oxygen and yttrium is critical for the formation of dense Y-rich oxides. However, only few studies have reported the effect of oxygen content on the microstructure and mechanical properties of ODS steels. Herein, we employed gas atomization reactive synthesis to prepare pre-alloy powders and then hot isostatic pressing (HIP) to consolidate two 22Cr-5Al ODS steels with different oxygen content. Our results showed Y-rich precipitates at and near grain boundaries of the as-HIPed alloys. Moreover, with the oxygen content increasing from 0.04 to 0.16 wt%, more precipitates precipitated in the as-HIPed alloy, and the ultimate tensile strength of the alloy was improved. However, increasing the oxygen content to 0.16 wt% led to formation of stripe and chain precipitates at and near grain boundaries, which caused a partial intergranular fracture of the as-HIPed alloy.

Comparison of Graphitic Carbon Nitrides Synthetized from Melamine and Melamine-Cyanurate Complex: Characterization and Photocatalytic Decomposition of Ofloxacin and Ampicillin

Graphitic carbon nitride (g-C3N4, hereafter abbreviated as CN) was prepared by the heating of melamine (CN-M) and melamine-cyanurate complex (CN-MCA), respectively, in air at 550 °C for 4 h. The specific surface area (SSA) of CN-M and CN-MCA was 12 m2 g−1 and 225 m2g−1 and the content of oxygen was 0.62 wt.% and 1.88 wt.%, respectively. The band gap energy (Eg) of CN-M was 2.64 eV and Eg of CN-MCA was 2.73 eV. The photocatalytic activity of the CN materials was tested by means of the decomposition of antibiotics ofloxacin and ampicillin under LED irradiation of 420 nm. The activity of CN-MCA was higher due to its high SSA, which was determined based on the physisorption of nitrogen. Ofloxacin was decomposed more efficiently than ampicillin in the presence of both photocatalysts.

Chemical Modification of B4C Films and B4C/Pd Layers Stored in Different Environments

B4C/Pd multilayers with small d-spacing can easily degrade in the air, and the exact degradation process is not clear. In this work, we studied the chemical modification of B4C films and B4C/Pd double layers stored in four different environments: a dry nitrogen environment, the atmosphere, a dry oxygen-rich environment, and a wet nitrogen environment. The XANES spectra of the B4C/Pd layers placed in a dry oxygen-rich environment showed the most significant decrease in the σ* states of the B–C bonds and an increase in the π* states of the B–O bonds compared with the other samples. X-ray photoelectron spectroscopy (XPS) measurements of the samples placed in a dry oxygen-rich environment showed more intensive B-O binding signals in the B4C/Pd layers than in the single B4C film. The results of the Fourier-transform infrared spectroscopy (FTIR) showed a similar decrease in the B–C bonds and an increase in the B–O bonds in the B4C/Pd layers in contrast to the single B4C film placed in a dry oxygen-rich environment. We concluded that the combination of palladium catalysis and the high content of oxygen in the environment promoted the oxidization of boron, deteriorated the B4C composition.

Effect of Oxygen Content and Temperature On Stabilization of Arsenic in Copper Smelting System

Arsenic-bearing wastes from copper smelting system are usually disposed by trapping them in slag tailing. However, arsenic in slag tailing is not that stable, which can infiltrate into the groundwater, threatening the environment and human health. The solidification/stabilization (S/S) of arsenic is the only way to deal with arsenic contamination. The flash smelting method shows relatively high S/S ability of arsenic, but the process and mechanism remain unclear. In this paper, we aim at revealing the effect of atmosphere on the S/S process of arsenic owing to the different content of oxygen in reaction shaft and sedimentation tank in copper smelting system. Calcium arsenate, SiO2, Fe2O3 and iron powders were sintered at different temperature in air and argon to simulate the S/S reaction. The results show that the sintering product is Fe-Si oxide in air and fayalite in argon, and the fayalite possesses better capacity to solidify arsenic than that of Fe-Si oxide. The toxicity characteristic leaching procedure (TCLP) results reveal that the leached concentration of arsenic from fayalite fabricated at 1200 ℃ is only 2.916 mg L-1, which satisfies the identification standard for hazardous substances in China. Furthermore, the theoretical calculation reveals that AsO4 and SiO4 tetrahedrons can be connected by O atoms when sintered in argon, and the Si-O-As covalent bond can evidently inhibit the release of As atom from fayalite. This work can not only clarify the S/S mechanism of arsenic in flash smelting process, but also provide theoretical guidances to dispose arsenic-bearing waste harmlessly.