A journey of over 200 years: early studies on wootz ingots and new evidence from Konasamudram, India

Recent new evidence emerged from the crucible steel production site of Konasamudram, Telangana, India. A hoard of 60 crucible steel ingots from this site offers a unique opportunity to study details of the early large-scale production of this fabled material, beginning with a detailed documentation of the weights and sizes of 45 of them. Historically, Konasamudram has been an important pre-modern crucible steel manufacturing and trading centre in India, as reported by Persian and European travelogues, and may have been the source of many of the early ingots studied during the past 200 years. Therefore, the aim of this work is to present a dimensional analysis of these ingots and interpret the data in the context of earlier studies, to address questions of consistency in manufacturing, standardization of weights and other physical attributes. The newly-discovered ingots show considerable uniformity in shape, size and weights, indicative of a single event production during the heydays of crucible steel making, while the ingots previously reported in the literature vary much more widely

Interaction of 3â-amino-5-cholestene with phospholipids in binary and ternary bilayer membranes

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Langmuir, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://doi.org/10.1021/la203589u.3β-Amino-5-cholestene (aminocholesterol) is a synthetic sterol whose properties in bilayer membranes have been examined. In fluid palmitoyl sphingomyelin (PSM) bilayers, aminocholesterol and cholesterol were equally effective in increasing acyl chain order, based on changes in diphenylhexatriene (DPH) anisotropy. In fluid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers, aminocholesterol ordered acyl chains, but slightly less efficiently than cholesterol. Aminocholesterol eliminated the PSM and DPPC gel-to-liquid crystalline phase transition enthalpy linearly with concentration, and the enthalpy approached zero at 30 mol% sterol. Whereas cholesterol was able to increase the thermostability of ordered PSM domains in a fluid bilayer, aminocholesterol under equal conditions failed to do this, suggesting that its interaction with PSM was not as favorable as cholesterol’s. In ternary mixed bilayers, containing 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), PSM or DPPC, and cholesterol at proportions to contain a liquid-ordered phase (60:40 by mol of POPC and PSM or DPPC, and 30 mol% cholesterol), the average life-time of trans parinaric acid (tPA) was close to 20 ns. When cholesterol was replaced with aminocholesterol in such mixed bilayers, the average life-time of tPA was only marginally shorter (about 18 ns). This observation, together with acyl chain ordering data, clearly shows that aminocholesterol was able to form a liquid-ordered phase with saturated PSM or DPPC. We conclude that aminocholesterol should be a good sterol replacement in model membrane systems for which a partial positive charge is deemed beneficial