1,3,5-Trinitro-s-triazine, or cyclotrimethylene trinitramine, or RDX, is a sensitive, secondary explosive, which has been the subject of a number of studies regarding the sensitivity and mechanism of decomposition in energetic materials. Several initial mechanistic steps have been proposed for RDX decomposition, with no conclusive agreement upon any one as the definitive pathway. Our research utilizes density functional theory (DFT)-based calculations and concepts, particularly the nuclear Fukui function, to analyze the effects of additive/depletive electronic perturbation upon vapor conformers and crystal RDX structures. Since the nuclear Fukui function is a measure of the physical stress that a nucleus encounters upon a change in the electron population, it may provide useful information regarding the role of each atom in unimolecular decomposition. The results illustrate that both homolytic cleavage of N-N bonds and elimination of HONO from RDX exhibit favorability as initial steps in the decomposition of RDX in either phase. The nuclear Fukui function proved a valuable tool for gaining insight into the initial steps of unimolecular reactions.

Organic molecules are prone to polymorphic formation in the solid state due to the rich diversity of functional groups that results in comparable intermolecular interactions, which can be greatly affected by the selection of solvent and other crystallization conditions. Intermolecular interactions are typically weak forces, such as van der Waals and stronger short-range ones including hydrogen bonding, that are believed to determine the packing of organic molecules during the crystal-growth process. A different packing of the same molecules leads to the formation of a new crystal structure. To disclose the underlying causes that drive the molecule to have various packing motifs in the solid state, an electronic concept or function within the framework of conceptual density functional theory has been developed, namely, crystallization force. The concept aims to describe the local change in electronic structure as a result of the self-assembly process of crystallization and may likely quantify the locality of intermolecular interactions that directs the molecular packing in a crystal. To assess the applicability of the concept, 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile, so-called ROY, which is known to have the largest number of solved polymorphs, has been examined. Electronic calculations were conducted on the seven available crystal structures as well as on the single molecule. The electronic structures were analyzed and crystallization force values were obtained. The results indicate that the crystallization forces are able to reveal intermolecular interactions in the crystals, in particular, the close contacts that are formed between molecules. Strong correlations exist between the total crystallization force and lattice energy of a crystal structure, further suggesting the underlying connection between the crystallization force and molecular packing.

The polymorphism of indomethacin lies in various meta-stable conformations of the molecule that are results of different orientations between the two aromatic indole and phenyl rings. The analysis of electronic and nuclear Fukui functions permits the revelation of local energy barriers that determine the conformational diversity and, for the case of indomethacin, the conformational polymorphism.

Image-guided FNA with immediate evaluation is a reliable means to obtain diagnostic material and triage for ancillary tests.

Fine-needle aspiration (FNA) remains the most effective and safe method of evaluating thyroid nodules for potential surgical management. Since 2007, the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) has standardized nomenclature for thyroid FNA and provided an evidence-based malignancy risk for each of its diagnostic categories. Using TBSRTC criteria, most thyroid nodules can effectively be categorized as either "benign" or "malignant" and referred for definitive management without further testing. However, many thyroid nodules fall into an indeterminate TBSRTC category, most notably atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS). Efforts have been made to elucidate further clinical utility from indeterminate cases, including nomenclature modifications and molecular-based testing modalities. The use of "atypia qualifiers" in AUS/ FLUS cases appears to refine the diagnosis to provide a more specific risk of malignancy. Notably, AUS qualifiers of "cannot exclude papillary thyroid carcinoma" and "cannot exclude follicular neoplasm" appear to carry a higher risk of malignancy than other AUS qualifications in multiple studies. Molecular panels appear to hold particular promise as adjuncts in helping to delineate worrisome from non-worrisome thyroid nodules with indeterminate cytology. In particular, the miRInform test (Asuragen), an oncogene mutation panel, appears to show utility in its ability to "rule in" a malignant or neoplastic process, although it is limited by a relatively high false-negative rate. Conversely, the Afirma test (Veracyte), a gene expression classifier (GEC), appears to show clinical promise due to its high negative predictive value; albeit with a significant false-positive rate. Herein, we provide an overview of TBSRTC diagnostic categories and a literature review of new attempts to further refine indeterminate categories; as well as a review of the most commonly used commercial molecular panels used in thyroid cytopathology.