Histologic grading of breast cancers

Breast cancer is the most common cancer in women. Histologic grading is one of the prognostic factors in breast cancer. The present study performed in analytic descriptive method and based on the slide review of beast biopsies received in the pathology department of 5th Azar Hospital from 1976 to 1978, and on the basis of Bloom-Richardson criteria (Mitoses, tubule formation and nuclear pleomorphism). The results are consist of: 1) Infiltrating duct carcinoma is the most common histopathologic form, and tubular carcinoma is the least common 2) The most common age is 36-45 years 3) There is meaningful relationship between mitoses and tubule formation and between pleomorphism and tubule formation. But there is no relation between nuclear pleomorphism and tubule formation in the tumor. Histologic grading of breast carcinoma should be reported by pathologist for clear determination of prognosis and also the best choice for management of the tumors

Bimolecular recombination in methylammonium lead triiodide perovskite is an inverse absorption process

Photovoltaic devices based on metal halide perovskites are rapidly improving in efficiency. Once the Shockley–Queisser limit is reached, charge-carrier extraction will be limited only by radiative bimolecular recombination of electrons with holes. Yet, this fundamental process, and its link with material stoichiometry, is still poorly understood. Here we show that bimolecular charge-carrier recombination in methylammonium lead triiodide perovskite can be fully explained as the inverse process of absorption. By correctly accounting for contributions to the absorption from excitons and electron-hole continuum states, we are able to utilise the van Roosbroeck–Shockley relation to determine bimolecular recombination rate constants from absorption spectra. We show that the sharpening of photon, electron and hole distribution functions significantly enhances bimolecular charge recombination as the temperature is lowered, mirroring trends in transient spectroscopy. Our findings provide vital understanding of band-to-band recombination processes in this hybrid perovskite, which comprise direct, fully radiative transitions between thermalized electrons and holes