Cathodoluminescence of MAPbCl Halide Perovskite Single Crystal.

Chloride perovskites are semiconductors with a near-ultraviolet bandgap that are promising for applications in optoelectronics and photonics. One of the most studied representatives of this family is the methylammonium lead chloride MAPbCl (MA = CHNH). Low-temperature luminescence spectroscopy of this material demonstrates a complex emission structure.

Environmental sustainability of post-orthodontic dental retainers: a comparative life-cycle assessment of Hawley and Essix retainers.

Background: Environmental sustainability has been brought into the limelight due to the global climate crisis. This crisis is driven by human activities and even the healthcare sector is no exception. Within dentistry, orthodontics is a large global market; hence, the use of post-orthodontic retainers has a significant environmental footprint.

Internal Vibrations of Pyridinium Cation in One-Dimensional Halide Perovskites and the Corresponding Halide Salts.

We investigate vibrations of the pyridinium cation PyH = CHNH in one-dimensional lead halide perovskites PyPbX and pyridinium halide salts PyHX (X = I, Br), combining infrared absorption and Raman scattering methods at room temperature. Internal vibrations of the cation were assigned based on density functional theory modeling. Some of the vibrational bands are sensitive to perovskite or the salt environment in the solid state, while halide substitution has only a minor effect on them.

Polarized Raman Study of Internal Vibrations of the Organic Cation in 3-Cyanopyridinium Lead Tribromide Post-perovskite.

In this work, we apply polarized Raman spectroscopy for study of internal vibrations of the 3-cyanopyridinium cation in the halide post-perovskite (3cp)PbBr (3cp = 3-CN-CHNH). For a single cation, the vibrational frequencies and intensities of the Raman signal were calculated using the density functional theory. Selection rules were established for vibrations of cations in the crystal.

Diffuse Reflectance Spectroscopy with Dilution: A Powerful Method for Halide Perovskites Study.

Halide perovskites and their low-dimensional analogs are promising semiconductor materials for solar cells, LEDs, lasers, detectors and other applications in the area of photonics. The most informative optical property of semiconductor photonics materials is the absorption spectrum enabling observation of the fundamental absorption edge, exciton structure, defect-related bands, etc. Traditionally, in the study of halide perovskites, this spectrum is obtained by absorption spectroscopy of thin films or diffuse reflectance spectroscopy of powders.

Excitonic Enhancement and Excited Excitonic States in CsPbBr Halide Perovskite Single Crystals.

Halide perovskites are novel photonics materials promising numerous applications in fields such as photovoltaics, LED light sources, microlasers, and radiation detectors. Many halide perovskites are direct-gap semiconductors, and Wannier-Mott excitons play a significant role in their optical properties near the fundamental absorption edge. The high oscillator strength of these states favors applications where efficient interaction with light is required.

The Dopaminergic Dysfunction and Altered Working Memory Performance of Aging Mice Lacking Gamma-synuclein Gene.

Background: It was previously shown that inactivation of gamma-synuclein which is a small soluble neuronal protein affects psycho-emotional status and cognitive abilities in knock-out mice.

Objective: Determine the role of gamma-synuclein inactivation on memory performance in aging animals.

Method: We used the passive avoidance test and acute amphetamine administration in aging gammasynuclein knock-out mice.

Sleep Disorders Associated With Alzheimer's Disease: A Perspective.

Sleep disturbances, as well as sleep-wake rhythm disturbances, are typical symptoms of Alzheimer's disease (AD) that may precede the other clinical signs of this neurodegenerative disease. Here, we describe clinical features of sleep disorders in AD and the relation between sleep disorders and both cognitive impairment and poor prognosis of the disease. There are difficulties of the diagnosis of sleep disorders based on sleep questionnaires, polysomnography or actigraphy in the AD patients.

Mild cognitive impairment due to Alzheimer disease: Contemporary approaches to diagnostics and pharmacological intervention.

Alzheimer disease (AD) and related forms of dementia are among the main medical and social problems in the economically developed countries. It is connected with significant increase in human life span in these regions and with the absence of efficient medicines for treatment and prevention of such diseases. Lack of positive results in the developing of novel drugs for AD treatment stimulates special attention on problem of early diagnosis and drug discovery for pharmacotherapy on the very early stages of dementia, in particular, on mild cognitive impairments (MCI) due to AD.

Chemosensitizing Activity of Histone Deacetylases Inhibitory Cyclic Hydroxamic Acids for Combination Chemotherapy of Lymphatic Leukemia.

Background: Anti-tumor effect of hydroxamic acid derivatives is largely connected with its properties as efficient inhibitors of histone deacetylases, and other metalloenzymes involved in carcinogenesis.

Objective: The work was aimed to (i) determine the anti-tumor and chemosensitizing activity of the novel racemic spirocyclic hydroxamic acids using experimental drug sensitive leukemia P388 of mice, and (ii) determine the structure-activity relationships as metal chelating and HDAC inhibitory agents.

Method: Outbreed male rat of 200-220 g weights were used in biochemical experiments.