TOWARD A MORE EFFICIENT UTILISATION OF BETALAINS AS PIGMENTS FOR DYE-SENSITIZED SOLAR CELLS

We report on the use of natural dyes, betalains, as pigments for Dye-Sensitized Solar Cells (DSSC). Time-Dependent Density Functional Theory calculations provide the electronic spectra of the various types of betalain dyes and allow a discussion of their matching to the solar spectrum. Experimentally, we vary parameters such as the nature of the extracting solvent, the pH and the composition of the extract, to optimize the fabrication of DSSCs using betalains. Based on UV-Vis spectra correlated with electro-optic measurements providing the photovolatic conversion efficiency under standard AM1.5 conditions we find that the decrease of the pH of the dye solution leads to an increase of the DSSC performance, likely due to the increasing ratios of betacyanins with respect to betaxanthins in the extracts as well as the possible hydrolysis of betanin to betanidin. In order to fabricate better DSSCs using betalain natural dyes, we propose to use water as extracting solvent, to increase the content in betacyanins on the photoanode by a preliminary purification and to raise the stability of the dyes preferably by using anti-oxidizing copigments that do not interact with the substrate

Therapeutical options in the ascit -peritonitis management. Surgical medical aspects

Catedra 2 Chirurgie, USMF ”Nicolae Testemiţeanu”Lucrarea îşi propune să analizeze principalele aspecte diagnostice şi terapeutice ale ascit-peritonitei (AP) prin prisma cazuisticii din Departamentul Chirurgie Hepatobilio-Pancreatică raportat la studiul actual al problemei.This paper aims to analyze the main diagnostic and therapeutic aspects in ascit-peritonits, for this we analyzed the Chisinau Surgery Department hepatobiliopancreatic statistics and we report them to the present literature

Executive functioning and quality of life in acromegaly

Emilia Solomon,1,2 Dumitru Brănișteanu,1,3 Andrei Dumbravă,4 Radu Gheorghe Solomon,5 Lorànt Kiss,5 Mihai Glod,1 Cristina Preda1,3 1Faculty of Medicine, Grigore T. Popa University of Medicine and Pharmacy, Iaşi, Romania; 2Department of Endocrinology, CF University Hospital, Iaşi, Romania; 3Department of Endocrinology, “Sf. Spiridon” Hospital, Iaşi, Romania; 4Faculty of Psychology, Alexandru Ioan Cuza University, Iaşi, Romania; 5ISUD, Faculty of Medicine, University Lucian Blaga, Sibiu, Romania Introduction: Active acromegaly is a rare chronic endocrine disorder caused by excessive growth hormone (GH). Clinical studies suggest that cognitive performance is impaired in acromegaly – particularly executive function as well as short- and long-term memory. This study compared the quality of life (QoL) and executive functioning in acromegaly patients vs healthy controls.Materials and methods: This was an observational case–control study on 38 subjects divided into 19 acromegaly patients and 19 matched controls. The groups were evaluated for QoL, attention, and executive function. All subjects completed Acromegaly Quality of Life Questionnaire (AcroQoL), Trail Making Test (parts A and B), Stroop, and phonemic fluency tests.Results: Acromegaly patients had an AcroQoL global score that was significantly lower than controls. There were significant differences between the acromegaly group and the control group in terms of the physical effects (P=0.001) and appearance (P<0.001) but not for personal relationships (P=0.421). Acromegaly patients performed worse in the trail making test part B. They provided significantly fewer words than healthy subjects in phonemic fluency testing. Although patients performed generally worse than controls, no significant differences were noted in the trail making test part A, Stroop test, and the constrained phonemic fluency.Conclusion: Acromegaly patients display worse executive functioning than healthy controls and have a decreased QoL. Keywords: acromegaly, cognition, growth hormone, executive functio

DFT Study of Binding and Electron Transfer from a Metal-Free Dye with Carboxyl, Hydroxyl, and Sulfonic Anchors to a Titanium Dioxide Nanocluster

We report results of density functional theory (DFT) calculations of a metal-free dye, 5-(4-sulfophenylazo)salicylic acid disodium salt, known as Mordant Yellow 10 (MY-10), used as sensitizer for TiO2 dye-sensitized solar cells (DSSCs). Given the need to better understand the behavior of the dyes adsorbed on the TiO2 nanoparticle, we studied various single and double deprotonated forms of the dye bound to a TiO2 cluster, taking advantage of the presence of the carboxyl, hydroxyl, and sulfonic groups as possible anchors. We discuss various binding configurations to the TiO2 substrate and the charge transfer from the pigment to the oxide by means of DFT calculations. In agreement with other reports, we find that the carboxyl group tends to bind in bidentate bridging configurations. The salicylate uses both the carboxyl and hydroxyl substituent groups for either a tridentate binding to adjacent Ti(IV) ions or a bidentate Ti-O binding together with an O-H-O binding, due to the rotation of the carboxyl group out of the plane of the dye. The sulfonic group prefers a tridentate binding. We analyze the propensity for electron transfer of the various dyes and find that for MY-10, as a function of the anchor group, the DSSC performance decreases in the order hydroxyl + carboxyl > carboxyl > sulfonate