Effect of connectivity on the carrier transport and recombination dynamics of perovskite quantum dot networks

Quantum dot (QD) solids are being widely exploited as a solution-processable technology to develop photovoltaic, light-emission, and photo-detection devices. Charge transport in these materials is the result of a compromise between confinement at the individual QD level and electronic coupling among the different nanocrystals in the ensemble. While this is commonly achieved by ligand engineering in colloidal-based systems, ligand-free QD assemblies have recently emerged as an exciting alternative where nanostructures can be directly grown into porous matrices with optical quality as well as control over their connectivity and hence charge transport properties. In this context, we present a complete photophysical study comprising fluence and temperature-dependent time-resolved spectroscopy to study carrier dynamics in ligand-free QD networks with gradually varying degrees of interconnectivity, which we achieve by changing the average distance between the QDs. Analysis of the photoluminescence and absorption properties of the QD assemblies, involving both static and time-resolved measurements, allows us to identify the weight of the different recombination mechanisms, both radiative and non-radiative, as a function of QD connectivity. We propose a picture where carrier diffusion, which is needed for any optoelectronic application and implies inter-particle transport, gives rise to the exposure of carriers to a larger defect landscape than in the case of isolated QDs. The use of a broad range of fluences permits extracting valuable information for applications demanding either low or high carrier injection levels and highlighting the relevance of a judicious design to balance recombination and diffusion.Comment: 16 pages, 5 figures in main manuscript; 11 pages, 11 figures in Supporting Informatio

Estrogen Promotes Mandibular Condylar Fibrocartilage Chondrogenesis and Inhibits Degeneration via Estrogen Receptor Alpha in Female Mice

Temporomandibular joint degenerative disease (TMJ-DD) is a chronic form of TMJ disorder that specifically afflicts people over the age of 40 and targets women at a higher rate than men. Prevalence of TMJ-DD in this population suggests that estrogen loss plays a role in the disease pathogenesis. Thus, the goal of the present study was to determine the role of estrogen on chondrogenesis and homeostasis via estrogen receptor alpha (ERα) during growth and maturity of the joint. Young and mature WT and ERαKO female mice were subjected to ovariectomy procedures and then given placebo or estradiol treatment. The effect of estrogen via ERα on fibrocartilage morphology, matrix production, and protease activity was assessed. In the young mice, estrogen via ERα promoted mandibular condylar fibrocartilage chondrogenesis partly by inhibiting the canonical Wnt signaling pathway through upregulation of sclerostin (Sost). In the mature mice, protease activity was partly inhibited with estrogen treatment via the upregulation and activity of protease inhibitor 15 (Pi15) and alpha-2- macroglobulin (A2m). The results from this work provide a mechanistic understanding of estradiol on TMJ growth and homeostasis and can be utilized for development of therapeutic targets to promote regeneration and inhibit degeneration of the mandibular condylar fibrocartilage.National Institute of Dental & Craniofacial Research of the National Institutes of Health under Award Numbers R56DE020097 (SW) and F32DE026366 (JR

Invasive squamous cell carcinoma originating from a giant penile condyloma

In this case study, we present an unusual case with squamous cell carcinoma originating from a giant condyloma acuminata completely surrounding the penis. A 57-year-old circumcised heterosexual male patient presented with a penile lesion existing for 20 years. Incisional biopsy revealed acanthosis of the squamous epithelium. The patient was operated on under spinal anaesthesia. The lesion was resected circumferentially with macroscopic clearance, resulting in complete degloving of the penile shaft. Neurovascular bundles were preserved. The penile skin was constructed with a split thickness skin graft. Histopathological analysis of the lesion revealed an invasive and well-differentiated squamous cell carcinoma arising on a condyloma, and the surgical margins were free from tumour. The patient was staged as G2 T1 N0 M0 and was followed for one year. He did not have any erectile dysfunction and could engage in intercourse. Pelvic tomographic and physical examination findings did not reveal any episode of recurrence or metastasis. When encountering patients with giant condyloma acuminata, it should not be forgotten that it may be accompanied by squamous cell carcinoma. In addition, tissue excision should be as extensive as possible while keeping in mind the importance of the function. This is the first case of a penile-degloving surgery for giant penile condyloma, supporting conservative and preserving penile surgery for such tumours. © 2016, © The Author(s) 2016

Exchange Market Reform, Inflation, and Fiscal Deficits

This paper examines the short- and long-run effects of exchange market reform in developing countries. The first part reviews the recent experience of Guyana, India, Jamaica, Kenya, Sierra Leone, and Sri Lanka with exchange market reform. The second part studies analytically the short-run dynamics of the parallel market premium and the money supply upon unification, when the post-reform regime consists of either a pure float or a managed float. The third part discusses the impact of unification on inflation and quasi-fiscal deficits, and identifies a variety of implicit taxes and subsidies that must be taken into account in assessing the longer-run effects of exchange market reform.