Transparent and Conformal Microcoil Arrays for Spatially Selective Neuronal Activation

Magnetic stimulation represents a compelling modality for achieving neuronal activation with high spatial resolution and low toxicity. Stimulation coils can be designed to achieve localized, spatially asymmetric fields that target neurons of a particular orientation. Furthermore, these devices may be encapsulated within biopolymers thereby avoiding direct metal/tissue interfaces that could induce chronic inflammation and glial scarring. Herein, we report a multiplexed microcoil array for localized activation of cortical neurons and retinal ganglion cells. We designed a computational model that related the activation function to the geometry and arrangement of coils, and selected a geometry with a region of activation <50 microns wide. We then fabricated SU8/Cu/SU8 tri-layer devices which were flexible, transparent and conformal and featured four individually-addressable microcoil stimulation elements. Interfaced with ex vivo cortex or retina slices from GCaMP6-transfected mice, we observed that individual neurons located within 40 microns of the element tip could be activated repeatedly and in a dose (power) dependent fashion. Taken together, these results highlight the potential of magnetic stimulation devices for brain-machine interfaces and could open new routes toward bioelectronic therapies including prosthetic vision devices.

Improving natural organic matter and turbidity removal from surface water by pre-coagulation combined with ozone/ultrasound

Recently, we showed that the pre-treatment with ultrasound/ozone (US/O3) could remarkably enhance the performance of coagulation in removing natural organic matter (NOM) and turbidity from surface waters. In the present study another of our aim was to investigate whether the pretreatment with coagulation combined with post-oxidation (US/O3) can also remove NOM, turbidity and coliform from the same water resources. NOM and turbidity removal were measured by UV absorbance at 254 (UV254) and a turbidimeter, respectively. Aluminum sulfate (alum), ferric chloride (FC), and poly aluminum chloride (PACl) were tested as coagulants. The disinfection potential of the US/O3 process was evaluated by measuring coliform counts. The effects of different input variables including ozone dose, power intensity, ultrasounds frequency, reaction time, coagulant type, dose of coagulant and coagulant aid was examined on the process performance. Design of experiments (DoE) and surface response methodology (RSM) techniques were employed to optimize the operating parameters. Individual coagulation process decreased NOM and turbidity up to 33 and 15%, however pre-coagulation combined with US/O3 decreased NOM and turbidity 75 and 32%, respectively. Although the PACL was the best coagulant in the sole coagulation, but in pre-coagulation combined with US/O3 process, FC exhibited the best performance. Treatment with US/O3 following pre-coagulation decreased the amount of coagulant and coagulant aid needed for the treatment. Pre-coagulation followed by US/O3 improves the NOM, turbidity and coliform removal, so could be considered as potential method for removing NOM, turbidity and coliform.

The functional state of the thyroid system of children exposed in utero as a result of the Chernobyl disaster

A cohort of children exposed in utero after the Chernobyl accident is formed (n=422). Individual absorbed dose (AD) for the fetal thyroid was estimated from direct measurements of dose power for the maternal thyroid and was 0.01-4.5 Gy. The mean AD for the thyroid of pregnant women was 24.09+1.17 sGy, that of prenatally exposed children 44.74+2.58 sGy. Thyroid status of 195 exposed children and 220 controls is examined. Thyroid hormones were radioimmunoassayed and measured by enzyme immunoassay using standard diagnostic kits. Serum triiodothyronine concentrations were significantly increased in prenatally exposed children of both sexes (p<0.05 for boys and p<0.01 for girls). Serum thyroxin and thyroxin-binding globulin (TBG) levels were decreased in exposed boys in comparison with the control (p<0.05). In exposed girls thyroxin levels were virtually normal, but there was a tendency to an increase of thyroglobulin (t=1.6) and to a decrease of TBG (t= 1.7) in comparison with the control. The mean TBG concentration in the serum was below the norm in both groups. The results can be indicative of thyroid dysfunction in remote periods after prenatal exposure to radioactive iodine.

Influence of a Modified Plant Extract on Activity of Antioxidant Enzymes and Concentration of Pigments in Gamma-Irradiated Plants of Maize and Wheat

The influence of a medicinal plant extract, immobilised by ligands, on the activity of antioxidant enzymes and photosynthetic pigment concentration of wheat and maize was studied. The object of study was seed of drought-resistant firm durum wheat (Triticum durum Desf.) and maize (Zea mays L.). Seeds were subjected to general uniform γ-radiation from a 60Co source on a Rkhund installation at average dose power of MD = 0.306 Gy/sec. Before radiation seeds were treated in modified extract from medicinal plants. The treatment of seeds with 0.1 and 0.01% solution of modified extract from Hypericum, Dandelion, and Calendula caused significant reduction in processes initiated by radiation and in formation of free radicals. On the basis of the obtained results it was concluded that the used modified plant extract collection had a protective effect, reducing the amount of free radicals produced by γ-irradiation.

Разработка физико-топологической модели реакции мощного вертикального ДМОП транзистора на воздействие импульсного гамма-излучения

A method for developing models of semiconductor devices with two-dimensional nonuniform concentration profiles of donors and acceptors in working regions of a semiconductor device structure is for the first time proposed based on a complex of physical-topological modeling of charge carrier transport and process simulation of the forming processes of the device structure. The application of process simulation is due to the need to correctly define the parameters of the semiconductor device structure, which are used as initial data to calculate the electron transport according to the physical-topological model. The parameters of production processes of ion implantation, diffusion, and lithography, which were refined during process simulation, are determined for a high-power metal—oxide—semiconductor (MOS) transistor forming by the double diffusion method in accordance with known electrical characteristics and measured geometrical sizes of the structure. This results in two-dimensional distribution profiles of donors and acceptors in p – n junctions necessary to calculate the transistor breakdown under the effect of pulsed γ radiation. Breakdown processes are modeled with the help of the physical-topological model based on the Poisson and continuity equations as well as expressions for the diffusion and drift current densities in the transistor. Accounting for carriers formed at the instant of γ irradiation is implemented by the introduction of the dependence of the generation coefficient of electron–hole pairs on the radiation-dose power. The results of calculations correlate well with the experimental data, which makes it possible to give a conclusion regarding the adequacy of the proposed complex model.

Yielding ability and quality characteristics of Chinese cabbage in condition of imitation of radiation influence during the space mission to Mars

Chinese cabbage plants, Vesniyanka cultivar, were grown under natural illumination in normal radiation and were placed in condition of periodic y-irradiation produced by the GAMMA-BREEZ source. The irradiation was carried out each 7 days for 4 hours with dose power 5 mSv/h. The summarized dose during all vegetation time was 80 mSv. The root zone of plants was moistened with water containing the different concentrations of deuterium. Radioactive influence on plants did not take effect in yielding abilities and ascorbic acid content in leaves. The reduction of deuterium concentration in water caused the plant productivity was twice as much as before, but otherwise it resulted the active accumulation of nitrates in leaves.