An analysis of quadrupole splitting of the Mössbauer spectra of ferritin and iron-dextran complexes in relation to the iron core microstructural variations

Mössbauer spectra of human liver ferritin and some pharmaceutically important iron-dextran complexes as ferritin models were measured at 87 K (frozen solutions) and at both 87 and 295 K (lyophilized forms). The Mössbauer spectra consisted of paramagnetic doublets only. However, the spectral line shapes were not Lorentzian and these Mössbauer spectra were better fitted using a superposition of two or more quadrupole doublets or using a distribution of quadrupole splittings. The differences of the maximal quantity of quadrupole doublets for better fitting of various Mössbauer spectra of ferritin and iron-dextran complexes were compared with the fitting using the distribution of quadrupole splitting for additional analysis. It is possible that variations of the quantity of quadrupole doublets for better fitting of Mössbauer spectra of ferritin and iron-dextran complexes may be related to heterogeneous iron cores in the samples. This heterogeneity is supposed to be different for various samples and changed for lyophilized samples and for frozen solutions as well as for various temperatures

Surface stiffening and enhanced photoluminescence of ion implanted cellulose - polyvinyl alcohol - silica composite

Novel Cellulose (Cel) reinforced polyvinyl alcohol (PVA)-Silica (Si) composite which has good stability and in vitro degradation was prepared by lyophilization technique and implanted using N3+ ions of energy 24 keV in the fluences of 1 x 10(15), 5 x 10(15) and 1 x 10(16) ions/cm(2). SEM analysis revealed the formation of microstructures, and improved the surface roughness on ion implantation. In addition to these structural changes, the implantation significantly modified the luminescent, thermal and mechanical properties of the samples. The elastic modulus of the implanted samples has increased by about 50 times compared to the pristine which confirms that the stiffness of the sample surface has increased remarkably on ion implantation. The photoluminescence of the native cellulose has improved greatly due to defect site, dangling bonds and hydrogen passivation. Electric conductivity of the ion implanted samples was improved by about 25%. Hence, low energy ion implantation tunes the mechanical property, surface roughness and further induces the formation of nano structures. MG63 cells seeded onto the scaffolds reveals that with the increase in implantation fluence, the cell attachment, viability and proliferation have improved greatly compared to pristine. The enhancement of cell growth of about 59% was observed in the implanted samples compared to pristine. These properties will enable the scaffolds to be ideal for bone tissue engineering and imaging applications.G.M.S. acknowledges CSIR, India (Grant no: 09/468 (0474)/2013-EMR-I) and S.N.K. thanks the award of Erasmus-Mundus Svaagata for providing financial support to carry out this research. G.M.S., N.S. and S.N.K. acknowledge the support of UGC National facility for characterization facility. J.A.G.T. acknowledges the support of the Spanish Ministry of Economy and Competitiveness (MINECO) through the project DPI2015-65401-C3-2-R (including the FEDER financial support). CIBER-BBN, Spain is an initiative funded by the VI National R&D Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program. CIBER actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. AFM was conducted by the microscopy service of the UPV, whose advice was greatly appreciated.Shanthini, GM.; Sakthivel, N.; Menon, R.; Nabhiraj, PY.; Gómez-Tejedor, JA.; Meseguer Dueñas, JM.; Gómez Ribelles, JL.... (2016). Surface stiffening and enhanced photoluminescence of ion implanted cellulose - polyvinyl alcohol - silica composite. Carbohydrate Polymers. 153:619-630. https://doi.org/10.1016/j.carbpol.2016.08.016S61963015

INVESTIGATION OF RECOMBINATION PROCESSES IN POROUS SILICON BY PHOTOLUMINESCENT METHODS

The aim is to determine the stationary and kinetic characteristics of the porous silicon (PS) luminescence, to analyse the contribution of the radiative and non-radiative recombination processes into the luminescent signal, to evaluate the heterogeneity of the luminescent properties over thickness of PS. The complex investigation of the PS radiative characteristics has been performed. The internal quantum output of the PS photoluminescence has been evaluated. The luminescent properties of PS over the cross-section of the sample have been studied. The conclusion about increase of the middle diameter in the silicon nanostructures upon the external surface deep into PS has been made. It has been shown that under action of the ultra-violet radiation in presence of the oxygen the degradation is heterogeneous over thickness of the porous layer. The distribution of the non-radiative recombination centres over the material profile has been evaluated. The work results are actual for new perspective applications of PS in the microelectronics and can be used for further theoretical and experimental investigations of the PS properties. Application field: physics of semiconductors, microoptoelectronicsAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Gastroesophageal Reflux Disease and Coronary Heart Disease: Is There a “Mutual Burden” Syndrome?

Aim. This review aims to generalize data on the mutual aggravating effect on the course of gastroesophageal reflux disease (GERD) and coronary heart disease (CHD).General findings. The combination of CHD and GERD is a common clinical situation. In recent years, more and more information has appeared indicating a non-accidental character of the comorbidity of both diseases. In addition to common risk factors, a number of pathophysiological mechanisms have been established that determine a pathogenetic relationship between CHD and GERD. Reflux disease contributes adversely to chronic coronary heart disease, e.g. by increasing the risk of developing myocardial infarction (MI). The co-occurrence of myocardial ischemia episodes (registered by ECG) with those of heartburn has been identified. A correlation between pathological reflux and ST segment depression has been found. A trigger role of reflux in relation to angina attacks and heart rhythm disturbances has been determined. The pro-arrhythmic effects of GERD on the myocardium are explained by an imbalance of the autonomic nervous system with a predominance of the parasympathetic tone. In turn, both stable angina and myocardial infarction contribute to a more aggressive and refractory course of reflux esophagitis (RE), thus triggering reflux symptoms.Conclusion. The comorbid course of coronary heart disease and GERD is based on complex associations; this clinical situation is characterized by a mutual burden syndrome. Given the high prevalence of a combination of both diseases, it seems relevant to develop pathogenetically substantiated approaches to the management of this category of patients