At the same time, economists have been documenting the loss of work opportunities and earning power by workers without college degrees as manufacturingemployment has declined. In 2013, David Autor, David Dorn, and Gordon Hanson published a study that estimated the labor market impacts resulting from increased trade competition following China’s entrance into the World Trade Organization, an effect often referred to as the “China shock.” Dozens of studies have since used the regional variation in job and income losses caused by the China shock to measure the adverse impacts of job displacement on family structures, crime, health, and other social indicators. Some supporters of industrial subsidies and higher tariffs have expressed the hope that these dynamics can be put into reverse.
Results from a study combining experiments and simulations could overturn the assumption that amorphous forms of the same compound have the same molecular arrangement. The team behind the work claims to have prepared three amorphous forms of the diureticdrughydrochlorothiazide and determined that they have distinct properties and distinct types of disorder. ‘If polyamorphism is proved in the future to be a universal—or at least not a very rare—phenomenon, then the pharmaceutical industry will need to make screens for polyamorphism and this will also be an opportunity for patenting,’ comments Inês Martins, from the University of Copenhagen in Denmark, who led the work with Thomas Rades.
Crystallineactive pharmaceutical ingredients (APIs) often suffer from poor solubility. A common strategy to circumvent this problem is converting APIs into their amorphous form. This has been demonstrated for various APIs, including hydrochlorothiazide. However, the physical properties of polyamorphs are dependent on how they were prepared. Given there are no straightforward techniques to study how molecules interact and organise themselves in amorphous materials, the area is poorly understood.
‘The problem out of the gate with polyamorphism as a concept is how to tell the difference between a well-defined metastableamorphous structure and an unrelaxed one that simply results from kinetically trapped defects introduced during processing. This is hard to define since the amorphousstructure is statistical in any case,’ comments Simon Billinge, who studies the structure of disordered materials at Columbia University in the US. ‘They process the samples very differently. We know—from our own work—that this results in amorphous phases with very different stabilities against recrystallisation, for example, but is this polyamorphism? On the other hand, they find that the pair distribution functions of each of their “forms” are identical. There is no experimental evidence for a distinct structure. Taken together, the results do little to advance my understanding of polyamorphism.’
The team also says the simulations corroborated its experimental results that polyamorph I can transform into polyamorph II, while the opposite conversion did not take place.