A cloud web platform for analysis and interpretation of atomic pair distribution function (PDF) data (PDFitc) is described. The platform is able to host applications for PDF analysis to help researchers study the local and nanoscale structure of nanostructured materials. The applications are designed to be powerful and easy to use and can, and will, be extended over time through community adoption and development. The currently available PDF analysis applications, structureMining, spacegroupMining and similarityMapping, are described. In the first and second the user uploads a single PDF and the application returns a list of best-fit candidate structures, and the most likely space group of the underlying structure, respectively. In the third, the user can upload a set of measured or calculated PDFs and the application returns a matrix of Pearson correlations, allowing assessment of the similarity between different data sets. structureMining is presented here as an example to show the easy-to-use workflow on PDFitc. In the future, as well as using the PDFitc applications for data analysis, it is hoped that the community will contribute their own codes and software to the platform.
Electromagnetic (EM) field exposure during materials synthesis offers the opportunity to engineer novel atomic structures and modify reaction kinetics beyond the capabilities of conventional routes. We demonstrate the first experimental...
Ritonavir is a drug of the protease inhibitor class, marketed by Abbvie™ -as of 1996 under the name of Norvir ® -for the treatment of adult and pediatric patients infected with HIV. Lopinavir is a protease inhibitor drug used in combination with ritonavir in therapy and prevention of HIV infection. Both drugs display polymorphism, which may lead to severe commercial implications for pharmaceutical manufacturing [1]. One way to overcome such problems is the development of amorphous formulations like Kaletra commercial medicine. In this work, we use a ball-mill system and an agate mortar and pestle to obtain individual amorphous ritonavir and lopinavir samples as well as their mixtures. First of all, we identify and characterize the crystal forms present in the raw samples of lopinavir and ritonavir, as well as quantify the mass concentrations of each crystal phase using X-ray powder diffraction and the Rietveld method. Ritonavir tends to recrystallize after some time. On the other hand, the mixture of an already amorphous lopinavir sample with ritonavir seems to facilitate its amorphization. The ball-mill processing of ritonavir and lopinavir together results in the production of unexpected crystalline forms of ritonavir. Pair distribution function (PDF) analysis shows the mixed samples reveal a higher r-dependence of ritonavir up to 2 Å (first two peaks). At the same time, the lopinavir dependence tends to increase for a higher-r signal.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.