Naphthalimide Trifluoroacetyl Acetonate: A Hydrazine-Selective Chemodosimetric Sensor

The trifluoroacetyl acetonate naphthalimide derivative 1 has been synthesized in good yield. In acetonitrile solution, compound 1 reacts selectively with hydrazine (NH2NH2) to give a five-membered ring. This leads to OFF-ON fluorescence with a maximum intensity at 501 nm as well as easily discernible color changes. Based on a readily discernible and reproducible 3.9% change in overall fluorescence intensity, the limit of detection for 1 is 3.2 ppb (0.1 mu M), which is below the accepted limit for hydrazine set by the U.S. Environmental Protection Agency (EPA). Compound 1 is selective for hydrazine over other amines, including NH4OH, NH2OH, ethylenediamine, methylamine, n-butylamine, piperazine, dimethylamine, triethylamine, pyridine, and is not perturbed by environmentally abundant metal ions. When supported on glass-backed silica gel TLC plates, compound 1 acts as a fluorimetric and colorimetric probe for hydrazine vapor at a partial pressure of 9.0 mm Hg, with selectivity over other potentially interfering volatile analytes, including ammonia, methylamine, n-butylamine, formaldehyde, acetaldehyde, H2O2, HCl, and CO2 being observed. Probe 1 can also be used for the detection of hydrazine in HeLa cells and does so without appreciable interference from other biologically abundant amines and metal ions.U.S. National Science Foundation CHE-1057904Robert A. Welch Foundation F-1018CRI project grant from National Research Foundation of Korea (NRF)Korea government (MSIP) 2009-0081566Chemistr

The economic opportunities and constraints of green growth

노트 : Asie.Visions is an electronic publication dedicated to Asia. With contributions by French and international experts, Asie.Visions deals with economic, strategic, and political issues. The collection aims to contribute to the global debate and to a better understanding of the regional issues at stake. It is published in French and/or in English and upholds Ifri’s standards of quality (editing and anonymous peerreview)

Characterization of Lactose Fatty Acid Esters for their Microbial Growth Inhibitory Activity and Emulsification Properties

Sugar esters, substances made from bonding fatty acid tails to a sugar head, can play a number of key roles in food systems from antimicrobial agents to emulsifiers. These unique and very useful properties result from their water-loving and water-avoiding ends. Lactose, a sugar found in milk, based esters are important, as they are environmentally friendly and inexpensive, however, they are not very well understood. I created four different types of lactose esters: lactose monooctanoate (LMO), lactose monodecanoate (LMD), lactose monolaurate (LML) and lactose monomyristate (LMM), and then compared them to each other to see which would be the best emulsifier and which would be the best antimicrobial. My previous studies showed that LML was inhibitory against Listeria monocytogenes a common food pathogen. This encouraged us to evaluated the microbial inhibitory (bacterial killing) properties of LMO, LMD, LMM, along with LML, specifically, the influence of the fatty acid chain length in each ester and how that influenced my results. The esters, in order of highest microbial inhibitory properties, were LML, LMD, LMM followed by LMO. LML was inhibitory against all the Gram- positive bacteria tested including Bacillus cereus, Mycobacterium KMS, Streptococcussuis, L. monocytogenes, Enterococcus faecalis, and Streptococcus mutans but not Gram-negative bacteria (Escherichia coli O157:H7). Sugar esters are a large class of emulsifiers used in the food industry, and so my second research objective was to evaluate the influence of the fatty acid chain length on the emulsification properties of LMO, LMD, LML and LMM and compare them to each other and controls (Tween-20 and Ryoto L-1695) in a standard oil-in-water (O/W) emulsion. I did this by observing how long my emulsions lasted after mixing before they would start to separate. I also looked at the actual size of the oil drops in each of my emulsions, the smaller the oil drops remained, the better they stay in the emulsion and thus the more stable the emulsion. My results showed that the best emulsifier was LML, followed by LMD, LMM, and LMO, respectively. Therefore, my lactose esters contained both microbial inhibitory and emulsification activities. L. monocytogenes is an infamous food pathogen and one of the largest sources of food-borne illness from dairy foods in the United States. Addition of LMD and LML previously were shown to have microbial inhibitory effects in my lab so I wanted to see how well they would work in a food: milk. In general, bacterial deaths in the LMD milk samples were great and many times greater than the LML samples. However, both were greatly affected by milk fat content and how warm each of the samples were kept. LMD may play a useful role in increasing the safety of some foods