High-pressure cryogelation of nanosilica and surface properties of cryosilicas

Silica cryogels (cryosilicas) in a powder state were synthesized with different concentrations of fumed silica A-300 (CA-300 = 5-20 wt.%), sonicated in aqueous suspension, then frozen at -14 oC at different pressures in a high-pressure stainless steel reactor (a freezing bomb), and dried in air at room temperature. To analyze the effects of low temperature and high pressure, samples were also prepared at -14 oC or room temperature and standard pressure. The structural and adsorption properties of the powder materials were studied using nitrogen adsorption, high-resolution transmission electron microscopy, infrared spectroscopy, thermogravimetry, low-temperature 1H NMR spectroscopy and thermally stimulated depolarization current. The structural, textural, adsorption and relaxation characteristics of high-pressure cryogel hydrogels and related dried powders are strongly dependent on the silica content in aqueous suspensions frozen at 1, 450 or 1000 atmospheres and then dried. The largest changes are found with CA-300 = 20 wt.% which are analyzed with respect to the interfacial behavior of nonpolar, weakly polar and polar adsorbates using low temperature 1H NMR spectroscopy

Severe Secondary Polycythemia in a Female-to-Male Transgender Patient While Using Lifelong Hormonal Therapy: A Patient's Perspective

After a registered drug is available on the market and used in everyday circumstances, hitherto unknown adverse drug reactions (ADRs) may occur. Furthermore, the patient can experience a previously unknown course of a known ADR. Voluntary reports by patients play an important role in gaining knowledge about ADRs in daily practice. The Netherlands Pharmacovigilance Centre Lareb received a report from a 55-year-old female-to-male transgender patient who experiences secondary polycythemia while using lifelong testosterone therapy. The onset age of the symptoms was 38 years. The symptoms appeared gradually and after approximately 1 year it was clear that the patient's hemoglobin and hematocrit had started to increase. A Naranjo assessment score of 6 was obtained, indicating a probable relationship between the patient's polycythemia and use of the suspect drug. Polycythemia is a known ADR in testosterone treatment, but little attention has been paid to the possible severity and complications of these symptoms as well as the impact on the patient's well-being