Perylene-Grafted Silicas: Mechanistic Study and Applications in Heterogeneous Photoredox Catalysis.

A mechanistic study is herein presented for the use of heterogeneous photocatalysts based on perylene moieties. First, the successful immobilization of perylene diimides (PDI) on silica matrices is demonstrated, including their full characterization by means of electronic microscopy, surface area measurements, powder XRD, thermogravimetric analysis, and FTIR, Si and C solid-state NMR, fluorescence, and diffuse reflectance spectroscopies. Then, the photoredox activity of the material was tested by using two model reactions, alkene oxidation and 4-nitrobenzylbromide reduction, and mechanistic studies were performed.

Non-invasive and continuous monitoring of the sol-gel phase transition of supramolecular gels using a fast (open-ended coaxial) microwave sensor.

An open coaxial re-entrant microwave sensor has been used for the non-invasive and continuous monitoring of the sol-gel transition of physical gels characterized by different gelation mechanisms, solvents, compositions, and stabilities. Comparison of measurements by differential scanning calorimetry allowed the identification of the phase transition by a change in the dielectric properties of the material over time.

Plasmon excitation of supported gold nanoparticles can control molecular release from supramolecular systems.

Hybrid mesoporous silica materials containing gold nanoparticles (AuNPs) have been investigated as potential molecular delivery systems. The photophysical properties of AuNPs, particularly their plasmon band transitions, have been used to control the rate of the release of naproxen from the pores of mesoporous silica matrices. Two different approaches were employed to incorporate AuNPs into the silica network: that is, grafting (using 3-aminopropyltriethoxisilane) and direct absorption.

Introducing catalytic activity in helical nanostructures: microwave assisted oxathioacetalisation catalysed by Al-containing helical mesoporous silicas.

Al-containing helical mesoporous silicas have been synthesized and characterised by different techniques, showing outstanding activities (comparable to those obtained with sulfuric acid) in the oxathioacetalization of cyclohexane.

Human papilloma virus in oral squamous cell carcinoma in a Mexican population.

Objective: To determine the human papilloma virus (HPV) infection in oral cancer and its association with smoking and drinking habits.

Study Design: A cross-sectional study was performed; samples were collected from 51 patients with histological diagnosis of squamous-cell carcinoma were collected at the Instituto Nacional de Cancerología in Mexico City. HPV infection was detected by polymerase chain reaction, and the clinical characteristics of this population were analyzed.

[Usefulness of combining universal oligonucleotides in detecting human papillomavirus in cervical cancer and premalignant lesions].

Objective: To determine the prevalence of human papillomavirus (HPV) infection at different stages of the natural history of cervical cancer. Also, to optimize its detection by means of different sets of general primers.

Material And Methods: A descriptive, cross-sectional study was conducted between January and December 1999.