Public librairies in the city of Rome : from the Augustan age to the time of Diocletian

Drawing upon new evidence and exploiting new modes of analysis, we set out what can be known at present about the great imperial libraries of Rome. We trace their origins through the various conceptions of Caesar, Varro, and Pollio, and show that the imperial libraries were a continuation of late Republican practice : emperors acquired substantial book collections, stored them in several different structures, embellished the buildings with works of art, and allowed friends, scholars, and others to use the volumes. We pay close attention to the sources of the books, the uses and users of the libraries, and the fires that ravaged them. We argue that there were no libraries in the imperial thermae and that there were at most five or six libraries in existence at any one time. Even so, the books and works of art within them constituted an exceptional resource and a powerful cultural statement.Dix T. Keith, Houston George W. Public librairies in the city of Rome : from the Augustan age to the time of Diocletian. In: Mélanges de l'École française de Rome. Antiquité, tome 118, n°2. 2006. Antiquité. pp. 671-717

Using nuclear receptor activity to stratify hepatocarcinogens.

BackgroundNuclear receptors (NR) are a superfamily of ligand-activated transcription factors that control a range of cellular processes. Persistent stimulation of some NR is a non-genotoxic mechanism of rodent liver cancer with unclear relevance to humans. Here we report on a systematic analysis of new in vitro human NR activity data on 309 environmental chemicals in relationship to their liver cancer-related chronic outcomes in rodents.ResultsThe effects of 309 environmental chemicals on human constitutive androstane receptors (CAR/NR1I3), pregnane X receptor (PXR/NR1I2), aryl hydrocarbon receptor (AhR), peroxisome proliferator-activated receptors (PPAR/NR1C), liver X receptors (LXR/NR1H), retinoic X receptors (RXR/NR2B) and steroid receptors (SR/NR3) were determined using in vitro data. Hepatic histopathology, observed in rodents after two years of chronic treatment for 171 of the 309 chemicals, was summarized by a cancer lesion progression grade. Chemicals that caused proliferative liver lesions in both rat and mouse were generally more active for the human receptors, relative to the compounds that only affected one rodent species, and these changes were significant for PPAR (p0.001), PXR (p0.01) and CAR (p0.05). Though most chemicals exhibited receptor promiscuity, multivariate analysis clustered them into relatively few NR activity combinations. The human NR activity pattern of chemicals weakly associated with the severity of rodent liver cancer lesion progression (p0.05).ConclusionsThe rodent carcinogens had higher in vitro potency for human NR relative to non-carcinogens. Structurally diverse chemicals with similar NR promiscuity patterns weakly associated with the severity of rodent liver cancer progression. While these results do not prove the role of NR activation in human liver cancer, they do have implications for nuclear receptor chemical biology and provide insights into putative toxicity pathways. More importantly, these findings suggest the utility of in vitro assays for stratifying environmental contaminants based on a combination of human bioactivity and rodent toxicity

Profiling of the Tox21 10K compound library for agonists and antagonists of the estrogen receptor alpha signaling pathway

U ovom radu ću pojasniti što je strojno učenje, umjetna neuronska mreža, te konvolucijska neuronska mreža i kako je ona drukčija od obične neuronske mreže. U praktičnom dijelu ću razviti svoju konvolucijsku neuronsku mrežu u programskom jeziku Python, za razvrstavanje slika iz skupa podataka CIFAR-10, u 10 kategorija