Physical-Chemical Study of Anthracene Selective Oxidation by a Fe(III)-Phenylporhyrin Derivative.

In this work, we studied the anthracene oxidation by hydroxyl radicals. Hydroxyl radical was generated by reaction of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin Fe (III) (TPPFe) with hydrogen peroxide under visible radiation at a nitrogen atmosphere. The TPPFe was synthesized by Adler Method followed by metal complexation with Fe (III) chloride hexahydrate. Hydroxyl radical was detected by fluorescence emission spectroscopy and we studied kinetic of anthracene selective oxidation by hydroxyl radicals through the differential method. The TPPFe was characterized by UV-Vis spectrophotometry, Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM) measurements. The results indicated that TPPFE was compound by micro-particles with a size distribution of around 2500 nm. Kinetic results showed that the apparent rate constant for the oxidation of anthracene increased exponentially on as temperature increases, furthermore, the activation energy for the Anthracene oxidation by hydroxyl radicals under visible irradiation was 51.3 kJ/mol. Finally, anthraquinone was the main byproduct generated after oxidation of anthracene by TPP-Fe under visible irradiation.

Antimicrobial Activity against Fusarium oxysporum f. sp. dianthi of TiO2/ZnO Thin Films under UV Irradiation: Experimental and Theoretical Study.

We deposited bare TiO2 and TiO2/ZnO thin films to study their antimicrobial capacity against Fusarium oxysporum f. sp. dianthi. The deposit of TiO2 was performed by spin coating and the ZnO thin films were deposited onto the TiO2 surface by plasma-assisted reactive evaporation technique. The characterization of the compounds was carried out by scanning electron microscopy (SEM) and powder X-ray diffraction techniques. Furthermore, density functional theory (DFT) and time-dependent DFT (TDDFT) calculations were performed to support the observed experimental results. Thus, the removal of methylene blue (MB) by adsorption and posterior photocatalytic degradation was studied. Adsorption kinetic results showed that TiO2/ZnO thin films were more efficient in MB removal than bare TiO2 thin films, and the pseudo-second-order model was suitable to describe the experimental results for TiO2/ZnO (q e = 12.9 mg/g; k 2 = 0.14 g/mg/min) and TiO2 thin films (q e = 12.0 mg/g; k 2 = 0.13 g/mg/min). Photocatalytic results under UV irradiation showed that TiO2 thin films reached 10.9% of MB photodegradation (k = 1.0 × 10-3 min-1), whereas TiO2/ZnO thin films reached 20.6% of MB photodegradation (k = 3.9 × 10-3 min-1). Both thin films reduced the photocatalytic efficiency by less than 3% after 4 photocatalytic tests. DFT study showed that the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy gap decreases for the mixed nanoparticle system, showing its increased reactivity. Furthermore, the chemical hardness shows a lower value for the mixed system, whereas the electrophilicity index shows the biggest value, supporting the larger reactivity for the mixed nanoparticle system. Finally, the antimicrobial activity against F. oxysporum f. sp. dianthi showed that bare TiO2 reached a growth reduction of 68% while TiO2/ZnO reached a growth reduction of 90% after 250 min of UV irradiation.

Characteristics Upon Presentation of Patients with Type 2 Macular Telangiectasia in Puerto Rico.

OBJECTIVE: To describe the systemic disease associations and clinical features upon initial presentation of a cohort of patients with type 2 macular telangiectasia who live in Puerto Rico. METHODS: A retrospective review of patients with macular telangiectasia was performed in 4 private retina practices in Puerto Rico. The demographic and clinical characteristics were recorded. RESULTS: Twenty-one patients who were diagnosed with macular telangiectasia were included in the analysis. The median age of presentation was 62 years; 86% were female, and all patients were Hispanics. The median visual acuity at presentation was 20/50. A prior medical diagnosis of type II diabetes mellitus was found in 15 (71.4%) patients, essential hypertension in 12 (57.1%), and dyslipidemia in 9 (42.9%). All patients had bilateral disease. The most common ocular findings were the presence of right-angle vessels in 32 (76.2%) eyes and angiographic hyperfluorescence temporal to the fovea, found in 22 (52.4%) of the affected eyes. One eye had evidence of choroidal neovascularization. CONCLUSION: Our cohort showed a higher prevalence of type 2 diabetes in patients with type 2 macular telangiectasia than in other cohorts. It also supports the findings of other studies showing that macular telangiectasia patients are more likely to have type 2 diabetes and hyperlipidemia. However, the increased prevalence of diabetes and hyperlipidemia may be due to selection bias, and further studies are needed to assess the significance of these findings.

Effect of energy disorder in interfacial kinetics of dye-sensitized solar cells with organic hole transport material.

We describe the kinetic rates for dye regeneration in dye-sensitized solar cells with organic solid hole conductors, taking as a reference the experimental results of Haque et al. (ChemPhysChem 2003, 4, 89). Our model is based on Marcus rates for electron and hole transfer, emphasizing the Gaussian spread of energy levels in the molecular materials involved. We show that the energy disorder implies a broadening of the efficiency of hole transfer with respect to the thermodynamic driving force, as observed experimentally. The model also shows that tunning of the kinetic processes for high efficiency of energy conversion of the solar cell depends critically on the interplay between the reorganization energy and the broadening parameters of the energy distributions.

Mycobacterium tuberculosis complex detected by modified fluorescent in situ hybridization in lymph nodes of clinical samples.

INTRODUCTION: Lymph node tuberculosis (TB) is the leading cause of extrapulmonary tuberculosis and is the most frequently identified type in Aguascalientes, Mexico. Conventional diagnosis has serious limitations for rapid detection of extrapulmonary tuberculosis in clinical samples. Here PCR and modified FISH have been tested as complementary diagnosis methods for extrapulmonary tuberculosis. METHODOLOGY: The specific insertion sequence IS6110 for Mycobacterium tuberculosis complex was used to perform PCR and build DNA and PNA FISH probes (20bp). PCR and modified DNA and PNA FISH assays were performed to evaluate 41 lymph node paraffin-embedded tissue samples, in comparison with the histopathology diagnosis, which was considered the gold standard (22 positive and 19 negative). RESULTS: In comparison with histopathology diagnosis PCR showed 62.5 % sensitivity and 77.8 % specificity (χ(2) = 4.583 p < 0.05). Modified DNA FISH showed 71.4% sensitivity and 84.6% specificity (χ(2) = 11.21 p < 0.05). PNA FISH showed 66.7% sensitivity and 60.0% specificity (χ(2) = 2.93 p > 0.05). Ziehl Neelsen stain was positive in only four cases of 22 lymph node samples positive to histopathology.  In contrast, PCR and modified DNA FISH were positive in 20 cases of the same group. The negative cases were coincident in all tests. CONCLUSIONS: PCR and DNA FISH showed a significant increase in the number of cases detected and also showed higher sensitivity and specificity compared with data reported by traditional methodology. In developing countries, these techniques could help to complement the early diagnosis and timely treatment of extrapulmonary tuberculosis.