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Organic-inorganic perovskites are semiconductors used for applications in optoelectronics and photovoltaics. Micron and submicron perovskite patterns have been explored in semitransparent photovoltaic and lasing applications. In this work, we show that a polymeric medium can be used to create a patterned perovskite, by using a novel and inexpensive approach.
RESUMEN
Genetically encoded magnetic resonance imaging (MRI) contrast agents enable non-invasive detection of specific biomarkers in vivo. Here, we employed the hyper-CEST 129Xe NMR technique to quantify maltose (32 nM to 1 mM) through its modulation of conformational change and xenon exchange in maltose binding protein (MBP). Remarkably, no hyper-CEST signal was observed for MBP in the absence of maltose, making MBP an ultrasensitive "smart" contrast agent. The resonance frequency of 129Xe bound to MBP was greatly downfield-shifted (Δδ = 95 ppm) from the 129Xe(aq) peak, which facilitated detection in E. coli as well as multiplexing with TEM-1 ß-lactamase. Finally, a Val to Ala mutation at the MBP-Xe binding site yielded 34% more contrast than WT, with 129Xe resonance frequency shifted 59 ppm upfield from WT. We conclude that engineered MBPs constitute a new class of genetically encoded, analyte-sensitive molecular imaging agents detectable by 129Xe NMR/MRI.
RESUMEN
INTRODUCTION: Bejel (endemic syphilis) is usually encountered in children living in intertropical areas, although imported cases have been exceptionally reported in Europe. OBSERVATION: We report on a young girl aged 5 diagnosed in France, who had painless stomatitis and enlarged cervical nodes. Diagnosis of bejel was confirmed by serology, and spirochetes were shown inside mucous patches by biopsy specimen silver staining. Favorable clinical and serological outcome occurred following benzathin-penicillin therapy. Contamination is likely to have occurred in Mali where she had been living for several years, but secondary stage manifestations only appeared in France, where she was living for several months. DISCUSSION: Although rare in France, bejel should not be overlooked in children originating from countries where endemic syphilis has a high prevalence.