The ins and outs of drug-releasing vaginal rings: a literature review of expulsions and removals
EXPERT OPINION ON DRUG DELIVERY
Authors: Boyd, Peter; Merkatz, Ruth; Variano, Bruce; Malcolm, R. Karl
Abstract
Introduction There is considerable interest in vaginal ring technology for sustained/controlled administration of drugs to the human vagina. Seven drug-releasing vaginal rings have reached market and other experimental devices are in preclinical/clinical development. Although most women who have used rings are satisfied and find them acceptable, involuntary expulsions and voluntary removals are known to occur and are widely reported. There have been no previous efforts to review this topic and understand the factors contributing to expulsions. Areas covered This article will help researchers, clinicians and product developers better understand the pertinent factors and issues around ring expulsions and removals, and inform new research aimed at optimizing ring product design. The review contains four sections: (i) introduction to vaginal ring technology; (ii) discussion of the anatomical, physiological, device, and user factors affecting ring expulsion; (iii) review of involuntary expulsions; (iv) review of voluntary removals; and (v) concluding remarks/opinions. Expert opinion Further research is needed to better understand the factors contributing to involuntary ring expulsions and removals so that rings can be better designed to minimize rates of expulsion and to reduce removals. Determination of optimum ring dimensions and stiffness are likely key factors, alongside better counseling around removal and reinsertion.
An Ensemble Learning Approach for Urban Land Use Mapping Based on Remote Sensing Imagery and Social Sensing Data
REMOTE SENSING
Authors: Huang, Zhou; Qi, Houji; Kang, Chaogui; Su, Yuelong; Liu, Yu
Abstract
Urban land use mapping is crucial for effective urban management and planning due to the rapid change of urban processes. State-of-the-art approaches rely heavily on the socioeconomic, topographical, infrastructural and land cover information of urban environments via feeding them into ad hoc classifiers for land use classification. Yet, the major challenge lies in the lack of a universal and reliable approach for the extraction and combination of physical and socioeconomic features derived from remote sensing imagery and social sensing data. This article proposes an ensemble-learning-approach-based solution of integrating a rich body of features derived from high resolution satellite images, street-view images, building footprints, points-of-interest (POIs) and social media check-ins for the urban land use mapping task. The proposed approach can statistically differentiate the importance of input feature variables and provides a good explanation for the relationships between land cover, socioeconomic activities and land use categories. We apply the proposed method to infer the land use distribution in fine-grained spatial granularity within the Fifth Ring Road of Beijing and achieve an average classification accuracy of 74.2% over nine typical land use types. The results also indicate that our model outperforms several alternative models that have been widely utilized as baselines for land use classification.