Photonic Products Group Inc. (PPGI) of Northvale, N.J., reported it has received $700,000 through a secured promissory note with a five-year term from major shareholder Clarex Holdings Ltd. PPGI says it will use the money to buy state-of-the-art precision lens manufacturing equipment for its Laser Optics business unit and is augmenting its lens metrology and production capabilities for single-point diamond-turned aspheric lenses in its MRC Optics business unit. . . . Bedford, Mass.-based EM4 Inc. and its wholly owned subsidiary, EM4 Defense, a supplier of optoelectronic modules and optoelectronic design and manufacturing services for the defense and homeland security markets, has named Rebecca Smart as its director of quality. Smart previously worked in international quality control management for Raytheon. . . . Medical imaging device maker Positron Corp. of Houston, Texas, has appointed Joseph Oliverio as its new president, joining recently hired CEO J. David Wilson and Executive Vice President of Operations and CFO Corey N. Conn. Oliverio, a certified nuclear medicine technologist, replaces Griffith Miller, who remains as Positron's executive vice president of software and IT technologies.