Effect of Isomorphous Substitution on the Thermal Decomposition Mechanism of Hydrotalcites

Hydrotalcites have many important applications in catalysis, wastewater treatment, gene delivery and polymer stabilization, all depending on preparation history and treatment scenarios. In catalysis and polymer stabilization, thermal decomposition is of great importance. Hydrotalcites form easily with atmospheric carbon dioxide and often interfere with the study of other anion containing systems, particularly if formed at room temperature. The dehydroxylation and decomposition of carbonate occurs simultaneously, making it difficult to distinguish the dehydroxylation mechanisms directly. To date, the majority of work on understanding the decomposition mechanism has utilized hydrotalcite precipitated at room temperature. In this study, evolved gas analysis combined with thermal analysis has been used to show that CO₂ contamination is problematic in materials being formed at RT that are poorly crystalline. This has led to some dispute as to the nature of the dehydroxylation mechanism. In this paper, data for the thermal decomposition of the chloride form of hydrotalcite are reported. In addition, carbonate-free hydrotalcites have been synthesized with different charge densities and at different growth temperatures. This combination of parameters has allowed a better understanding of the mechanism of dehydroxylation and the role that isomorphous substitution plays in these mechanisms to be delineated. In addition, the effect of anion type on thermal stability is also reported. A stepwise dehydroxylation model is proposed that is mediated by the level of aluminum substitution.     

The synthesis of 14C‐labeled, 13CD2‐labeled saxagliptin,and its 13CD2‐labeled 5‐hydroxy metabolite

¹⁴C‐labeled saxagliptin, ¹³CD₂‐labeled saxagliptin, and its ¹³CD₂‐labeled 5‐hydroxy metabolite were synthesized to further support development of the compound for biological studies. This paper describes new syntheses leading to the desired compounds. A total of 3.0 mCi of ¹⁴C‐labeled saxagliptin was obtained with a specific activity of 53.98 μCi/mg (17.13 mCi/mmol). The radiochemical purity determined by HPLC was 99.29%, and the overall radiochemical yield was 3.0% based upon 100 mCi of [¹⁴C]CH₂I₂ starting material. By following similar synthetic routes, 580.0 mg of ¹³CD₂‐labeled saxagliptin and 153.1 mg of ¹³CD₂‐labeled 5‐hydroxysaxagliptin metabolite were prepared. Copyright © 2014 John Wiley & Sons, Ltd.     

Evaluation of Amigas Latinas Motivando el Alma (ALMA): A Pilot Promotora Intervention Focused on Stress and Coping Among Immigrant Latinas

Recent immigrant Latinas are at increased risk of poor mental health due to stressors associated with adapting to life in the United States. This study evaluated Amigas Latinas Motivando el Alma, a promotora intervention to reduce stress and promote health and coping among recent immigrant Latinas. Using a pre- and post-test design, we evaluated mental health outcomes, specifically, in promotoras. Promotoras’ knowledge levels related to role of promotora and stress management increased, depressive symptoms and stress levels decreased, and coping responses and perceived social support increased as well. Results suggest that promotora programs may be an effective way to improve mental health in recent immigrant Latinas.     

What Do We Need beyond Hemoglobin A1c to Get the Complete Picture of

Hemoglobin A1c (HbA1c) is currently the most commonly used marker for the determination of the glycemic status in people with diabetes and it is frequently used to guide therapy and especially medical treatment of people with diabetes. The measurement of HbA1c has reached a high level of analytical quality and, therefore, this biomarker is currently also suggested to be used for the diagnosis of diabetes. Nevertheless, it is crucial for people with diabetes and their treating physicians to be aware of possible interferences during its measurement as well as physiological or pathological factors that contribute to the HbA1c concentration without being related to glycemia, which are discussed in this review. We performed a comprehensive review of the literature based on PubMed searches on HbA1c in the treatment and diagnosis of diabetes including its most relevant limitations, glycemic variability and self-monitoring of blood glucose (SMBG). Although the high analytical quality of the HbA1c test is widely acknowledged, the clinical relevance of this marker regarding risk reduction of cardiovascular morbidity and mortality is still under debate. In this respect, we argue that glycemic variability as a further risk factor should deserve more attention in the treatment of diabetes.     

An unusual clinical presentation of myxoid dermatofibrosarcoma protuberans with a prominent vasculature: A potential pitfall in the diagnosis of myxoid soft tissue tumors

Dermatofibrosarcoma protuberans (DFSP) is a rare soft tissue tumor that arises primarily on the trunk and extremities but seldom on the scalp. Several variants of DFSP have been described, including myxoid DFSP. Although typical DFSP may have focally myxoid areas, myxoid DFSP, in which most of the stroma is myxoid, is rare and can pose diagnostic challenges. Here, we report a case of myxoid DFSP with an unusual clinical presentation that could have been mistaken for a lipoma. Additionally, the myxoid DFSP displayed prominent vasculature in a myxoid stroma, which could have been mistaken for a myxoid liposarcoma.