In 1997, the International Agency for Research on Cancer (IARC) upgraded its evaluation of crystalline silica to a Group 1 human carcinogen. Criticism against such decision is based on the lack of consistency in experimental results across animal species, violation of an important principle for causality, such as the replication of findings under different circumstances of exposure, and the lac...

Inhalation of dust containing crystalline silica is associated with a number of acute and chronic diseases including systemic autoimmune diseases. Evidence for the link with autoimmune disease comes from epidemiological studies linking occupational exposure to crystalline silica dust with the systemic autoimmune diseases systemic lupus erythematosus, systemic sclerosis, and rheumatoid arthritis...

Iron(III) oxide shows a polymorphism, characteristic of existence of phases with the same chemical composition but distinct crystal structures and, hence, physical properties. Four crystalline phases of iron(III) oxide have previously been identified: α-Fe2O3 (hematite), β-Fe2O3, γ-Fe2O3 (maghemite), and ε-Fe2O3. All four iron(III) oxide phases easily undergo various phase transformations in re...

In August 2015, the Curiosity Mars rover discovered tridymite, a high-temperature silica polymorph, in Gale crater. The existing model for its occurrence suggests erosion and detrital sedimentation from silicic volcanic rocks crater rim or central peak. chemistry mineralogy of tridymite-bearing rocks, however, are not consistent with material. Using data Curiosity, including chemical compositio...

The tendency of oxygen atoms to form just two bonds with a bond angle smaller than 180 allows the appearance of low energy atomic motions related to internal rotational degrees of freedom which, in a first approximation, involve neither bending nor stretching of bonds (“rigid unit modes” in silicates, “floppy modes” in glasses). A huge variety of compounds exhibit the oxygenbridge X-O-X basic u...

Background Tomaso Casoni (Figure 1A &1B) earned his fame by the test named after him [1]. Casoni was first to describe a test for immediate allergic reaction to hydatid fluid injected into the skin (Figure 2). This was in a time when hydatid disease caused by infection by Echinococcus granlulosus was endemic in Europe, Africa and the Middle East in addition to many other parts of the world. The...

This study assessed the effectiveness of a commercially available local exhaust ventilation (LEV) system for controlling respirable dust and crystalline silica exposures during concrete grinding activities. Surface grinding was conducted at six commercial building construction sites in Seattle, WA, by cement masons. Time-integrated filter samples and direct reading respirable dust concentration...