Effect of the alkaline cation size on the conductivity in gel polymer electrolytes and their influence on photo electrochemical solar cells.

The nature and concentration of cationic species in the electrolyte exert a profound influence on the efficiency of nanocrystalline dye-sensitized solar cells (DSSCs). A series of DSSCs based on gel electrolytes containing five alkali iodide salts (LiI, NaI, KI, RbI and CsI) and polyacrylonitrile with plasticizers were fabricated and studied, in order to investigate the dependence of solar cell performance on the cation size. The ionic conductivity of electrolytes with relatively large cations, K(+), Rb(+) and Cs(+), was higher and essentially constant, while for the electrolytes containing the two smaller cations, Na(+) and Li(+), the conductivity values were lower. The temperature dependence of conductivity in this series appears to follow the Vogel-Tamman-Fulcher equation. The sample containing the smallest cation shows the lowest conductivity and the highest activation energy of ∼36.5 meV, while K(+), Rb(+) and Cs(+) containing samples show an activation energy of ∼30.5 meV. DSSCs based on the gel electrolyte and a TiO2 double layer with the N719 dye exhibited an enhancement in the open circuit voltage with increasing cation size. This can be attributed to the decrease in the recombination rate of electrons and to the conduction band shift resulting from cation adsorption by TiO2. The maximum efficiency value, 3.48%, was obtained for the CsI containing cell. The efficiencies shown in this study are lower compared to values reported in the literature, and this can be attributed to the use of a single salt and the absence of other additives, since the focus of the present study was to analyze the cation effect. The highest short circuit current density of 9.43 mA cm(-2) was shown by the RbI containing cell. The enhancement of the solar cell performance with increasing size of the cation is discussed in terms of the effect of the cations on the TiO2 anode and ion transport in the electrolyte. In liquid electrolyte based DSSCs, the short circuit current density has been reported to decrease with the increasing size of the cation. However, in this work, it follows an opposite trend highlighting a major difference between liquid and quasi-solid electrolytes on the solar cell performance.

[Epignathus, hypolastic left heart syndrome, and trisomy 18 in a small for gestational age female twin]. / Epignato, sindrome del cuore sinistro ipoplasico e trisomia 18 in una gemella piccola per età gestazionale.

We describe a rare association of hypoplastic left heart syndrome, trismony 18, and epignathus in a 970 g female twin born at 37 weeks of gestational age. She died at 24 hours of age. Neonatologists and obstetricians should be aware of this rare association for a thorough prenatal counselling.

Relationship between external and internal structures in deciduous teeth: a multidisciplinary study.

AIM: The different dental structures of deciduous teeth have always been regarded with great interest in endodontics and restorative dentistry. Nevertheless, there are still few investigations on the morphology of deciduous teeth compared to the permanent ones, due to the difficulty in obtaining sound deciduous teeth suitable for measurement. The aim of this research is to evaluate and compare the internal and external structures of deciduous teeth from completely preserved hominid findings, using X-ray and micro-CT examination. METHODS: Samples were photographed using a digital camera and were then analysed by X-ray and micro-CT. Different parameters of external and internal structures were calculated to obtain a normalisation coefficient, called the P-factor. CONCLUSION: There is a constant correlation between external and internal structure, regardless of gender, type, shape or arch sector.

Diatom frustules enhancing the efficiency of gel polymer electrolyte based dye-sensitized solar cells with multilayer photoelectrodes.

The incorporation of nanostructures that improve light scattering and dye adsorption has been suggested for dye-sensitized solar cells (DSSCs), but the manufacture of photonic and nanostructured materials with the desired properties is not an easy task. In nature, however, the process of light-harvesting for photosynthesis has, in some cases, evolved structures with remarkable wavelength-sensitive light-trapping properties. The present work is focused on enhancing the efficiency of quasi solid-state DSSCs by capitalizing on the light trapping properties of diatom frustules since they provide complex 3-dimensional structures for scattering and trapping light. This study reports a promising approach to prepare TiO2 nanocrystal (14 nm) based photo-electrodes by utilizing the waveguiding and photon localization effects of nanostructured diatom frustules for enhancing light harvesting without deteriorating the electron conduction. Single and double-layered photo-electrodes were prepared with different frustule/nanocrystal combinations and conformations on transparent conductive oxide substrates. This study clearly reports impressive efficiency and short circuit current density enhancements of about 35% and 39%, respectively, due to the incorporation of diatom frustules extracted from a ubiquitous species. The SEM images obtained in this work reveal that the produced thin films had a remarkable surface coverage of evenly distributed frustules within the TiO2 nanoparticle layer. To the best of our knowledge, this study reports the first quasi solid-state DSSC based on a photo-electrode with incorporated bio-formed nanostructures.

[Plasma cell leukemia. Bibliographic review and ultrastructural study (by transmission and scanning electron microscopy) in 2 cases]. / La leucemia plasmacellulare. Revisione bibliografica e studio ultrastrutturale (al M.E.T. ed al M.E.S.) in due casi.

After a brief examination of the recent literature on plasma cell leukemia, the Authors describe the clinical features and the ultrastructural findings of the peripheral blood plasma cells, examined with transmission (T.E.M.) and scanning (S.E.M.) electron microscopes, of two patients with acute plasma cell leukemia. Both of them had a previous history of myeloma. T.E.M. confirmed the diagnostic value of the asynchronous plasma cells, and S.E.M. showed the characteristic microvilli and blebs, previously observed.

[Hypocholesterolemia in multiple myeloma. Inverse relation to the component M and the clinical stage]. / Ipocolesterolemia nel mieloma multiplo. Relazione inversa con la componente M e con lo stadio clinico.

The following parameters were studied in 41 Durie & Salmon staged patients with multiple myeloma: M component, bone lesions, marrow plasma cell %, Hb, leukocytes/mm3, lymphocytes/mm3, platelets/mm3, blood calcium, serum albumin, blood creatinine, BUN, total blood cholesterol. Linear correlation was adopted for the relation between two variables, using Pearson's coefficient, and Student's t test for unpaired data for comparison between the means. A significant (slight to excellent) inverse correlation was noted between total blood cholesterol and the M component. There was also a significant difference between the 1st and 2nd stage of the disease in this respect (P less than 0.05), between the 1st and 3rd (P less than 0.01), and between the 1st and the 2nd and 3rd combined (P less than 0.01). Progress of the disease appears to result in a fall in blood cholesterol. This parameter may be of assistance in differentiating slow-progressing forms from the more aggressive forms requiring treatment. The reasons for this change are discussed. Since cholesterol is an essential part of the cell membranes, attention is given to theories postulating a disorder in intracellular membrane metabolism.

Maxillary post-traumatic outcome correction. Literature review and personal experience. Part III: loss of maxillary substance (free flaps-distraction osteogenesis).

Revascularised free flaps retain dual vascularisation, both periosteal and medullary, undoubtedly present optimal survival and minimal re-absorption in view of the prevalence of osteogenetic rather than osteoclastic phenomena. A revascularised free bone flap involves the transfer of a certain amount of bone tissue, whether or not associated with a muscular, skin and/or facial component, with the features of an axial flap, dissecting the vascular stalk of the donor site and re-anastomosing both the arterial and the venous components on to recipient vessels in the site of the primary defect. The vessels in question measure only about 2-4 mm, so that micro-surgery techniques must be applied. For bone defects less than 6 cm, with upkeep of the mandibular or maxillary cortical bone and preservation of the soft tissues, with residual bone of at least 8 mm in height and 4 mm in thickness, alveolar distraction may represent a valid alternative to bone grafts, at the same time as ensuring an increase of the alveolar bone and intraoral soft tissues involved in the distraction process.