Rapid Quantification of 4,4'-Methylenedianiline by Surface-Enhanced Raman Spectroscopy.

Methylenedianiline (MDA) is a common industrial chemical with health and product safety concerns. Common analysis methods require many steps including extraction and derivatization ending in GC/MS or HPLC analysis, which minimize its use as an on-line or at-line technique. The procedure can take hours, prohibiting its use as a real-time decision-making tool as well as using valuable resources and laboratory space. The new method presented here has been validated for MDA quantification in industrial grease samples over the concentration range of 1-40 ppm 4,4'-MDA. We present comparative results to the currently accepted method with excellent fidelity. This analytical method using surface-enhanced Raman spectroscopy reduces sample preparation and analysis time by more than an hour while preserving method accuracy, specificity, and dynamic range.

Advanced prosthodontic training in the United States of America.

This article will consider prosthodontic specialty training in the United States. The history of prosthodontics as a specialty and the requirements necessary to be considered a prosthodontist will be explored. Today, a three-year postgraduate program is necessary to be considered an educationally qualified prosthodontist. Currently, there are 46 accredited advanced specialty education programs in the United States and approximately 3200 prosthodontists. The standards and training required for completion of these programs will be considered.

EMX homeobox genes regulate microphthalmia and alter melanocyte biology.

Melanocytes are specialized cells that produce melanin, the pigment responsible for skin, hair and retina color. They derive during embryogenesis from the precursor cells melanoblasts, which are neural crest cells committed to the pigment cell lineage. The differentiation of melanoblasts into melanocytes involves the expression of melanocyte-specific genes, particularly those responsible for melanin production, such as Tyr, Tyrp-1 and Dct, the expression of which depends on the melanocyte-specific transcription factor microphthalmia (Mitf). We have developed and executed a functional screen on melanocytes, with the aim of identifying genes involved in pigment cell biology. We have found Emx1 and Emx2, two highly related homeobox genes that when overexpressed in melanocytes can downregulate Mitf, Tyrp1, Dct and Tyr. Constitutive expression of Emx alters pigment cell morphology and growth properties: it confers TPA independence but not the ability to grow in soft agar. Spatial and temporal expression of Emx and Mitf during embryonic development suggests that Emx could be one factor that regulates correct expression of Mitf by inhibiting its activation in neuroepithelial derivatives other than melanocytes.