Laws of nanosize molybdenum (VI) oxide layers optical properties change as a result of heat treatment

The spectrophotometric method determines two absorption and reflection spectral areas of nanosize MoO3 layers - short-wave ?330 nanometers. It is stated by spectrophotometric, gravimetric and microscopic methods that in atmospheric conditions MoO3 layers transformation degree (d=10...130 nm) grows at time (1...140 minutes) and heat treatment temperatures (Т=373...600 К) (at constant layer thickness) increasing as well as at reduction of layers thickness. The reduction of absorption maxima at ?=350 nm and increase at ?=870 nanometers at heat treatment of MoO3 layers is revealed. The colour centers formation model is offered. It includes the center formation - anionic vacancy with one seized electron ([(Vа) ++ е]) during preparation of MoO3 layer, thermal electron transition from a valent zone on a level of the center, the second electron capture by the center ([(е Vа) ++ е])

Photolysis of lead azide in contact with copper oxide (I)

It is stated that alongside with decrease of photolysis velocity and photocurrent in the area of intrinsic absorption of lead azide the addition of Cu2O extends the range of spectral sensitivity, but preliminary processing of the system by light (?=365 nm) increases photolysis velocity. As a result of analysis of volt-ampere characteristic measurements, contact potential difference, contact photo-emf the model of system PbN6(Ам)-Cu2O photolysis including stages of generation, recombination, redistribution of nonequilibrium carrier in a contact field, formation of microheterogeneous PbN6(Ам)-Pb systems (photolytic product), as well as formation of photolytic final products is proposed

Influence of the method of synthesis on lead azide photolysis

Lead azide irrespective of method of synthesis shows the general kinetic regularities. On kinetic curves of photolysis speed PbN6(Аб) characteristic sites have been defined: initial, stationary, increased and saturation. Time of the sites realization as well as the photolysis speed depends on the way of PbN6(Аб) synthesis. Preliminary light processing of PbN6(Аб) at ?=380 nm and I=2·1015 quantum·sm-2·s-1 in vacuum (Р=1·10-5 Pа) along with increase in photolysis speed and photocurrent in own area of absorption results in appearence of new long-wave area of spectral sensitivity. Quantum outputs and constants of photolysis speed of PbN6(Аб) are determined. It is experimentally stated that the values of photocurrent observed in the field of long-wave threshold of photosensivity coincide with the designed values of photoemission current on the border of PbN6(Аб)-Pb. This fact as well as the measurements results of volt-ampere characteristics, contact photoelectrical moving force, contact potential difference reveals the formation of microheterogeneous PbN6(Аб)-Pb systems (a photolysis product) at photolysis of lead. A limiting stage of PbN6(Аб) photolysis is anion vacancies diffusion to neutral center of Pbn0

Silver azide photolysis

The preliminary silver azide light irradiation (?=365 nm, I>1·1015 quanta·cm-2·с-1) in vacuum (Р=1·10-5 Pа) alongside with increase in photolisys speed and a photocurrent results in occurrence new long-wave (up to ?=1280 nm) area of spectral sensitivity. Constants of silver azide photolysis speed are determined. As a result of measurements of a contact potential difference, volt - ampere of characteristics, a contact photoelectrical moving force, a photocurrent it is established, that at silver azide photolisys microheterogeneous systems AgN3 (А1) - Аg (a product photolisys) are formed. It is shown, that a limiting stage of silver azide photolisys is diffusion of the mobile ion of silver to neutral center (ТnAgm)0

Thermal transformations of aluminium-aluminium oxide systems in nanosize layers

Aluminium film of more than 2 nm thick indicates, but less than 2 nm do not indicate characteristic absorption and reflection bands for aluminium in range ?=190...1100 nm. By spectrophotometric, gravimetric and microscopic methods it is stated that thickness, mass and absorption, reflection spectrum of aluminium films (d=2...200 nm) undergo considerable transformations as a result of heat treatment in an interval of temperatures 373...600 K during 1...140 min in atmospheric conditions. Kinetic curve of transformation degrees, change of thickness and weights of samples are shown to be satisfactorily described in the context of the logarithmic law. It is established that changes of absorption spectra, thickness and weights of aluminium films are connected with the formation of aluminium oxide on their surface

Characterization of Ku702–NLS as Bipartite Nuclear Localization Sequence for Non-Viral Gene Delivery

Several barriers have to be overcome in order to achieve gene expression in target cells, e.g. cellular uptake, endosomal release and translocation to the nucleus. Nuclear localization sequences (NLS) enhance gene delivery by increasing the uptake of plasmid DNA (pDNA) to the nucleus. So far, only monopartite NLS were analysed for non-viral gene delivery. In this study, we examined the characteristics of a novel bipartite NLS like construct, namely NLS Ku70. We synthesized a dimeric structure of a modified NLS from the Ku70 protein (Ku702-NLS), a nuclear transport active mutant of Ku702-NLS (s1Ku702-NLS) and a nuclear transport deficient mutant of Ku702-NLS (s2Ku702). We examined the transfection efficiency of binary Ku702-NLS/DNA and ternary Ku702-NLS/PEI/DNA gene vector complexes in vitro by using standard transfection protocols as well as the magnetofection method. The application of Ku702-NLS and s1Ku702-NLS increased gene transfer efficiency in vitro and in vivo. This study shows for the first time that the use of bipartite NLS compounds alone or in combination with cationic polymers is a promising strategy to enhance the efficiency of non-viral gene transfer

SSCP Screening of Individual Aptamers

Aptamers are specific binding nucleic acids that emerge from in vitro selection. During the systematic evolution of ligands by exponential enrichment (SELEX) procedure, analysis of the sequences of the numerous selected individual molecules becomes an important step in the final stage of aptamer selection. The sequencing of cloned aptamers from the selected pool generally reveals groups of identical sequences and rarely occurring individual aptamers. This study demonstrates an approach similar to the single strand conformation polymorphism (SSCP) method used for mutation testing in genes. Human angiotensin I-specific aptamers have been used to show the efficiency of the SSCP method to classify selected individual sequences into identity groups, which minimizes sequencing efforts. Additionally, this approach allows the rapid isolation and identification of aptamers from a mixture

Target Groups for a Short Dexamethasone Course among Critically Ill COVID-19 Patients

Introduction. Corticosteroids are one of the most promising therapeutic agents for critically ill patients with coronavirus disease 2019 (COVID-19). Despite emerging data, assessed populations and regimens vary, and there are patient subgroups whose response to steroids remains unclear. We aimed to evaluate the outcomes of COVID-19 patients admitted to the intensive care unit (ICU) and treated with a short dexamethasone course to determine which patient categories derive the highest benefit. Methods. A retrospective cohort study was conducted using a prospectively collected single-center ICU database (April 1–October 1, 2020). Adult COVID-19 patients were assigned to dexamethasone (12 mg × 3 days) and usual care groups. Patient, management, and outcome data were extracted. The primary outcome was the 28-day ICU mortality. Subgroup analysis was performed to assess the impact of dexamethasone on mortality in patients with invasive mechanical ventilation (IMV). Results. Of 233 patients, 220 (median age: 65 years, 38% female) were included: 83 patients received dexamethasone and 137 received usual care. Overall, 28 (33.7%) and 54 (39.4%) patients in the dexamethasone and usual care groups, respectively, died within 28 days since ICU admission (rate ratio (RR) 0.86; 95% confidence interval (95% CI): 0.59–1.23; p=0.405). In the IMV cohort, dexamethasone did not decrease the 28-day mortality compared with usual care (47.5% vs. 62.0%; RR 0.78; 95% CI: 0.57–1.09; p=0.107). A subgroup analysis revealed significantly lower 28-day mortality in IMV patients <65 years receiving dexamethasone vs. usual care (22.6% vs. 48.5%; RR 0.47; 95% CI: 0.22–0.98; p=0.043), which was not seen in IMV patients ≥65 years (75.0% vs. 71.1%; RR 1.06; 95% CI: 0.79–1.42; p=0.719). Patients ≥65 years experienced hyperglycemia, bacterial infection, and septic shock significantly more often than younger patients who received dexamethasone (p=0.002, p=0.025, and p<0.001, respectively). Conclusions. A 3-day dexamethasone course is not associated with lower 28-day mortality in critically ill COVID-19 patients, either in the entire ICU cohort or in the IMV. Dexamethasone may significantly reduce the 28-day mortality in IMV patients <65 years, but not in the older IMV subgroup. Dexamethasone administration in patients ≥65 years is associated with a significantly higher rate of adverse events than that in younger patient