ABSTRACT
Dye-sensitized solar cells (DSSCs) are an increasingly attractive alternative energy source because of their low cost. Therefore, researchers have intensified efforts over the past decade to increase their energy conversion efficiency by employing new materials in each DSSC component. The present research focuses on synthesizing electrospun nanofibers as a potential new material as a counter electrode in DSSCs. Two Ru(ii) half sandwich 1,10 phenanthroline (phen) Ru-1 and 5-amino- phen Ru-2 complexes were prepared for its functionalization. As a deposition medium, poly(caprolactone) (PCL) dissolved in chloroform was used. Different Ru(ii) complex concentrations were made at 0.1% wt., 0.5% wt., and 1% wt. Thermal characterization studies using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were conducted to evaluate the behavior and weight loss of the samples with temperature variations. Fourier transform infrared spectroscopy (FTIR) measurements were taken to observe the bond interaction of the ruthenium complexes and the PCL. Finally, scanning electron microscopy (SEM) was used to structurally and morphologically evaluate the fiber distribution and porosity. These fibers have a homogeneous morphology, without bulbs, but with evident solid inlays on the surface, with fibers between â¼0.58 to 2.47 µm and percentages of porosity â¼45%. TGA and DSC thermograms show minor temperature variations that demonstrate the incorporation of the Ru(ii) complexes into the fiber. Furthermore, the melting and degradation temperature of the fibers is suitable for use in a DSSC approach. The incorporation of the ruthenium compounds into PCL fibers, along with the addition of the NH2 group into complex Ru-2, resulted in a higher current density for both anodic and cathodic peaks in Cyclic Voltammetry (CV). It is noteworthy that from I-V curves, PCL-Ru2 1% fibers demonstrated a conductivity of 0.461 µS cm-1, which is comparable to other PCL fibers carrying a higher metal load. Future studies will delve into the mechanical properties of these fibers to highlight their potential for application in this field.
ABSTRACT
Augmenting bacterial growth is of great interest to the biotechnological industry. Hence, the effect of poly (caprolactone) fibrous scaffolds to promote the growth of different bacterial strains of biological and industrial interest was evaluated. Furthermore, different types of carbon (glucose, fructose, lactose and galactose) and nitrogen sources (yeast extract, glycine, peptone and urea) were added to the scaffold to determinate their influence in bacterial growth. Bacterial growth was observed by scanning electron microscopy; thermal characteristics were also evaluated; bacterial cell growth was measured by ultraviolet-visible spectrophotometry at 600-nm. Fibers produced have an average diameter between 313 to 766 nm, with 44% superficial porosity of the scaffolds, a glass transition around ~64 °C and a critical temperature of ~338 °C. The fibrous scaffold increased the cell growth of Escherichia coli by 23% at 72 h, while Pseudomonas aeruginosa and Staphylococcus aureus increased by 36% and 95% respectively at 48 h, when compared to the normal growth of their respective bacterial cultures. However, no significant difference in bacterial growth between the scaffolds and the casted films could be observed. Cell growth depended on a combination of several factors: type of bacteria, carbon or nitrogen sources, casted films or 3D scaffolds. Microscopy showed traces of a biofilm formation around 3 h in culture of P. aeruginosa. Water bioremediation studies showed that P. aeruginosa on poly (caprolactone)/Glucose fibers was effective in removing 87% of chromium in 8 h.
ABSTRACT
Systemic lupus erythematosus is a chronic inflammatory autoimmune disorder that can affect any organ or system. Although pericarditis is the most frequent cardiac manifestation of this entity, usually is not a life threatening situation. Pericardial effusion causing cardiac tamponade is a very rare complication in lupus, with an incidence less than 2%. We report a case of pericardial tamponade due to SLE with severe hemodynamic involvement in a 21-year-old woman associated to rapidly progressive glomerulonephritis, acute pancreatitis, acute acalculous cholecystitis, pleural effusion, hematologic, cutaneous and neurologic lupus activity. Recognition of this rare manifestation of SLE may be life saving.
Subject(s)
Cardiac Tamponade/complications , Hemorrhage/diagnosis , Hemorrhage/etiology , Lupus Erythematosus, Systemic/complications , Pericardial Effusion/diagnosis , Pericardial Effusion/etiology , Pericarditis/diagnosis , Pericarditis/etiology , Adult , Female , HumansABSTRACT
El lupus eritematoso sistémico es una enfermedad autoinmune inflamatoria capaz de afectar cualquier aparato y sistema. Aunque la pericarditis es la manifestación cardíaca más frecuentemente observada, usualmente no es una situación que comprometa la vida del paciente. El taponamiento cardíaco ocasionado por derrame pericárdico en el lupus es una situación extremadamente rara, con una incidencia no mayor al 2%. Informamos el caso de una mujer de 21 años de edad con taponamiento cardíaco por lupus eritematoso sistémico, asociado a glomerulonefritis rápidamente progresiva, pancreatitis aguda, colecistitis aguda acalculosa, derrame pleural y actividad lúpica hematológica, cutánea y neurológica. El reconocimiento oportuno de esta rara manifestación del lupus puede salvar la vida de un paciente.
Systemic lupus erythematosus is a chronic inflammatory autoimmune disorder that can affect any organ or system. Although pericarditis is the most frequent cardiac manifestation of this entity, usually is not a life threatening situation. Pericardial effusion causing cardiac tamponade is a very rare complication in lupus, with an incidence less than 2%. We report a case of pericardial tamponade due to SLE with severe hemodynamic involvement in a 21-year-old woman associated to rapidly progressive glomerulonephritis, acute pancreatitis, acute acalculous cholecystitis, pleural effusion, hematologic, cutaneous and neurologic lupus activity. Recognition of this rare manifestation of SLE may be life saving.
