Laser induced photocurrent transients in semiconductor liquid-junction solar cells employing n-WSe2 and n-MoSe2 photoanodes

The effects of perturbing a semiconductor liquid-junction solar cell from dark equilibrium conditions with a nanosecond (5 nsec FWHM) laser pulse of greater than bandgap energy were studied. It was found that n-WSe(,2) and n-MoSe(,2) photoanodes in either I(\u27-)/I(,3)(\u27-) or Fe(\u272+)/Fe(\u273+) redox couple containing electrolyte solutions exhibit biexponentially decaying photocurrent transients in response to photoexcitation. For a given redox couple, n-WSe(,2) was found to yield slightly higher peak photocurrents than n-MoSe(,2) due to be more favorable band bending under dark conditions. The redox couple I(\u27-)/I(,3)(\u27-) was found to be superior to Fe(\u272+)/Fe(\u273+) in spite of more positive redox potential of the Fe(\u272+)/Fe(\u273+) couple. The I(\u27-)/I(,3)(\u27-) apparently adsorbs onto the semiconductor surface, negating the effects of surface states which tend to limit the amount of equilibrium band bending present. Quantum yields of charge transfer were determined for both redox couples as a function of laser pulse energy and energy density. Quantum yields of charge transfer were also determined for variation of the I(\u27-)/I(,3)(\u27-) couple concentration for a fixed excitation energy. The resultant nonlinear dependency appears to follow the adsorption isotherm for I(\u27-)/I(,3)(\u27-);Decay time constants and quantum yields of charge transfer as a function of added load resistance were studied. Limiting values for cell series resistance, capacitance, and shunt resistance were determined using a simple electronic model. A more complex phenomenological model which can be used to determine rates of charge transfer and recombination, as well as values for the electronic constants of the cell, has also been applied to the interpretation of the biexponential decays;A flashlamp-pumped transverse-flow dye laser was utilized as the photoexcitation source for the photocurrent transient studies. An in-depth description of the design, construction, and characterization of this laser system is presented

MECHANISMS OF THE INFLUENCE OF SODIUM-GLUCOSE COTRANSPORTER-2 INHIBITORS ON LDL RECEPTOR FUNCTION AND CARDIOVASCULAR RISK IN TYPE 2 DM (literature review)

In the modern world, the prevalence of dysmetabolic conditions, which are accompanied by corruption of lipid metabolism and the distribution of adipose tissue in the body, is increasing, and their consequences include cardiovascular diseases, type 2 diabetes mellitus (T2DM) etc. These pathologies are characterized by dyslipidemia, which reflects an imbalance in the processes of assimilation, transportation, absorption and use by fatty acids’ cells as energy and plastic substrates. A decrease in the relative content of unsaturated fatty acids in low-density lipoproteins (LDL) causes dysfunction of cell membranes, and an increase in serum concentration of LDL means corruption of their absorption by cells, which contributes to the development of atherosclerosis. Absorption of LDL by cells occurs through the interaction of apolipoprotein apoE/B-100 with the membrane receptor of LDL. The cell regulates the supply of lipids and cholesterol by synthesizing these receptors. The expression of LDL receptors is regulated at the level of transcription; particularly, it is stimulated by insulin and suppressed by excess cholesterol, the latter leading to abnormal accumulation of lipids in cells and tissues and the development of pathology in various organs. According to clinical and experimental studies and meta-analyses, drugs from the group of inhibitors of sodium-dependent glucose cotransporter-2 (SGLT2) have a pronounced protective cardiorenal effect in patients with T2DM and in cases of kidney and heart dysfunction. These beneficial effects are associated with improving insulin sensitivity, increasing the level of antiatherogenic HDL cholesterol, reducing the accumulation of lipids in visceral fat, stimulating lipolysis, and switching of oxidation towards the preferential use of lipid substrates. The paradoxical increase in LDL cholesterol is mainly due to less atherogenic large floating particles, and the negative effect is apparently counterweight by the wide range of beneficial pleiotropic effects of gliflozins

МЕТАБОЛІЧНI ЗМІНИ У ЖІНОК ТА ЧОЛОВІКІВ ІЗ ЦД 2 ТИПУ НА ТЛІ ЛІКУВАННЯ ІНГІБІТОРАМИ НЗКТГ-2

The use of morpho-metabolic approaches has a great practical importance in evaluation of the effectiveness of antihyperglycemic therapy in clinical  trials, in particular those related to new classes of inhibitors of sodiumdependent glucose-2 cotransporter inhibitors that have the ability to counteract many diabetic complications and cardiovascular disease. The aim of the study was to study the effect of treatment with SLGT2 inhibitors on morphological and metabolic parameters in men and women with type 2 diabetes. Materials and methods. During the study, 205 patients with type 2 diabetes, aged 30 to 81, with a disease duration of 1 to 20 years were examined. Patients underwent a clinical examination in the Department of Age Endocrinology and Clinical Pharmacology of the Institute of Endocrinology and Metabolism. V.P. Komissarenko of the National Academy of Medical Sciences of Ukraine. Patients received antihyperglycemic, antihypertensive and dyslipidemic therapy. Results.The study of anthropometric, morphological and biochemical parameters in groups of men and women with type 2 diabetes in the dynamics of longterm (12 month) use of iSLGT2- dapagliflozin allowed to identify certain sexual characteristics of the effects of this drug. In men group have been seen a gradual decrease in visceral fat levels during therapy. A decrease in BMI, BP, body weight and uricemia in men is most likely associated with a decrease in abdominal obesity and decreased insulin secretion. In women group use of dapagliflozin showed a significant decrease in total and visceral fat, accompanied by a decrease in relative water content, muscle and bone mass. Conclusions. Treatment of patients with type 2 diabetes with drugs of the group iSLGT2 for 12 months has reduced the degree of obesity and improved some indicators of body composition, uric acid.The use of morpho-metabolic approaches has a great practical importance in evaluation of the effectiveness of antihyperglycemic therapy in clinical  trials, in particular those related to new classes of inhibitors of sodiumdependent glucose-2 cotransporter inhibitors that have the ability to counteract many diabetic complications and cardiovascular disease. The aim of the study was to study the effect of treatment with SLGT2 inhibitors on morphological and metabolic parameters in men and women with type 2 diabetes. Materials and methods. During the study, 205 patients with type 2 diabetes, aged 30 to 81, with a disease duration of 1 to 20 years were examined. Patients underwent a clinical examination in the Department of Age Endocrinology and Clinical Pharmacology of the Institute of Endocrinology and Metabolism. V.P. Komissarenko of the National Academy of Medical Sciences of Ukraine. Patients received antihyperglycemic, antihypertensive and dyslipidemic therapy. Results.The study of anthropometric, morphological and biochemical parameters in groups of men and women with type 2 diabetes in the dynamics of longterm (12 month) use of iSLGT2- dapagliflozin allowed to identify certain sexual characteristics of the effects of this drug. In men group have been seen a gradual decrease in visceral fat levels during therapy. A decrease in BMI, BP, body weight and uricemia in men is most likely associated with a decrease in abdominal obesity and decreased insulin secretion. In women group use of dapagliflozin showed a significant decrease in total and visceral fat, accompanied by a decrease in relative water content, muscle and bone mass. Conclusions. Treatment of patients with type 2 diabetes with drugs of the group iSLGT2 for 12 months has reduced the degree of obesity and improved some indicators of body composition, uric acid

РОЛЬ ОСТЕОКАЛЬЦИНУ В РЕГУЛЯЦІЇ СЕКРЕЦІЇ ІНСУЛІНУ ТА ОСТЕОТРОПНИХ ЕФЕКТІВ РІЗНИХ КЛАСІВ ПРОТИДІАБЕТИЧНИХ ПРЕПАРАТІВ (огляд літератури і власні дослідження)

Background. Current data suggest that bone tissue produces hormonally active factors - modulators of metabolic processes throughout the body. The most significant osteoproteins is osteocalcin, the non-collagen structural protein of the bone matrix, which is synthesized by osteoblasts and enters the bloodstream during the resorption of bone tissue. Osteocalcin is involved in the regulation of energy balance, insulin secretion, peripheric insulin sensitivity, and adipocyte’s function, while being an important marker of bone remodeling. The aim of this study was to investigate the relationship between osteocalcin levels and metabolic parameters in 97 patients with type 2 diabetes over 50 years of age, in the course of pharmacotherapy using different classes of antidiabetic drugs, namely human insulin, glucagon-like peptide-1 agonists (aGLP), and sodium-glucose co-transporter 2 (SGLT2) inhibitors, depending on presence of obesity. Results. There was found the highest serum osteocalcin level in patients without obese who received a metabolically active therapy with insulin or aGLP-1, comparing to nonobese subjects of SGLT2 inhibitors therapy group. The lowest level of HbA1c and triglycerides observed in non-obese patients on the background of taking aGLP-1. Conclusion. It can be assumed that the factor determining the hypoglycemic efficacy of investigated drugs may be the pathogenesis of type 2 diabetes which depends on the degree of obesity, while the type of antidiabetic therapy has a corrective effect, probably mediated by changes in body weight and fat distribution.Background. Current data suggest that bone tissue produces hormonally active factors - modulators of metabolic processes throughout the body. The most significant osteoproteins is osteocalcin, the non-collagen structural protein of the bone matrix, which is synthesized by osteoblasts and enters the bloodstream during the resorption of bone tissue. Osteocalcin is involved in the regulation of energy balance, insulin secretion, peripheric insulin sensitivity, and adipocyte’s function, while being an important marker of bone remodeling. The aim of this study was to investigate the relationship between osteocalcin levels and metabolic parameters in 97 patients with type 2 diabetes over 50 years of age, in the course of pharmacotherapy using different classes of antidiabetic drugs, namely human insulin, glucagon-like peptide-1 agonists (aGLP), and sodium-glucose co-transporter 2 (SGLT2) inhibitors, depending on presence of obesity. Results. There was found the highest serum osteocalcin level in patients without obese who received a metabolically active therapy with insulin or aGLP-1, comparing to nonobese subjects of SGLT2 inhibitors therapy group. The lowest level of HbA1c and triglycerides observed in non-obese patients on the background of taking aGLP-1. Conclusion. It can be assumed that the factor determining the hypoglycemic efficacy of investigated drugs may be the pathogenesis of type 2 diabetes which depends on the degree of obesity, while the type of antidiabetic therapy has a corrective effect, probably mediated by changes in body weight and fat distribution

A RAIRS, TPD and femtosecond laser-induced desorption study of CO, NO and coadsorbed CO + NO on Pd(111)

Here we present a systematic study of the adsorption and laser induced desorption of CO, NO and CO + NO from a Pd(111) surface at a number of different coverages. We begin by characterising the surfaces using reflection-absorption infrared spectroscopy (RAIRS) and temperature programmed desorption (TPD). Experiments show that NO displaces pre-adsorbed CO considerably, but that CO has a much smaller effect on pre-adsorbed NO. In both cases, the preferred binding sites of CO are occupied by NO, displacing it to less favourable adsorption sites. Femtosecond laser induced desorption (fs-LID) shows that desorption of CO on Pd(111) follows a power law and is fairly independent of CO coverage, but for NO on Pd(111) we observe a clear deviation from a power law curve at higher coverages, with saturation being observed. This suggests that the cross-section for LID of NO is much larger than that for CO and that NO on Pd(111) is more photoactive than CO on Pd(111). Interestingly, for CO + NO on Pd(111) we find that coadsorption has a strong influence on the photodesorption process and that the structure of the overlayer is also important in controlling the photodesorption products, regardless of the order in which the two molecules are dosed