Tailorable cellulose II nanocrystals (CNC II) prepared in mildly acidic lithium bromide trihydrate (MALBTH)

Cellulose II nanocrystals were prepared from bleached kraft pulp via simultaneous hydrolysis of disordered cellulose and polymorph transformation in mildly acidic lithium bromide trihydrate followed by ammonium persulfate oxidation.

Sample Preparation of Posaconazole Oral Suspensions for Identification of the Crystal Form of the Active Pharmaceutical Ingredient

Determination of the polymorphic form of an active pharmaceutical ingredient (API) in a suspension could be really challenging because of the water phase and the low concentration of the API in this formulation. Posaconazole is an antifungal drug available also as an oral suspension. The aim of this study was to develop a sample-preparation method for polymorphic identification of the dispersed API by increasing the concentration of the API but with no compromise of polymorph stability. For this purpose, filtration, drying and centrifugation were tested for separating the API from the suspending medium. Centrifugation was selected because it succeeded in separating Posaconazole API with no polymorph transformation during the process. During this study, it was found that Posaconazole in oral suspensions is Form-S. However, when slower scanning rates were used for acquiring an XRPD pattern with better signal/noise ratio, Posaconazole was converted to Form I due to water loss. In order to protect the sample from conversion, different approaches were tested to secure an airtight sample including a commercially available XRPD sample holder with a dome-like transparent cap, standard polymethylmethacrylate (PMMA) sample holders covered with Mylar film, transparent pressure-sensitive tape and a transparent food membrane. Only usage of the transparent food membrane was found to protect the API from conversion for a period of at least two weeks and resulted in a Posaconazole Form-S XRPD pattern with no artificial peaks.

Non-crystallographic symmetry of liquid metal, flat crystallographic faults and polymorph transformation of the M7C3carbide

The fine lamellar fault structure of primary M7C3carbide particles in the heat-resistant Fe–Cr–Ni–C alloy of the HP series (0.45C–25Cr–35Ni) in the cast condition has been revealed using transmission electron microscopy. The lamellar fault structure is regarded as an inheritance of the initial melt structure. A one-to-one correspondence between the crystal structures of M7C3, M5C2, M3C and M23C6carbides and constructions of the projective 103Desargues configuration and its subconfigurations is shown. Mutual mapping between 103Desargues subconfigurations determines transformations of the ten-vertex equal-edged triangulated clusters appearing as building units of these carbides.

Effect of Y doping on high-pressure behavior of Ag2S nanocrystals

The effect of the dopant Y on high-pressure-induced polymorph transformation was investigated in Ag2S nanocrystals.