1.Formation of halogenated disinfection by-products in cobalt-catalyzed peroxymonosulfate oxidation processes in the presence of halides.
Xie W1, Dong W2, Kong D3, Ji Y2, Lu J4, Yin X2. Chemosphere. 2016 Apr 16;154:613-619. doi: 10.1016/j.chemosphere.2016.04.025. [Epub ahead of print]
Sulfate radicals (SO4-) generated by activation of peroxymonosulfate (PMS) and persulfate (PS) are highly oxidative and applied to degrade various organic pollutants. This research was designed to investigate formation of halogenated by-products in Co2+ activated PMS process in the presence of halides and natural organic matter (NOM). It was revealed that no halogenated by-products were detected in the presence of Cl- while 189 μg/L bromoform and 100.7 μg/L dibromoacetic acid (DBAA) were found after 120 h when 2 mg/L NOM, 0.1 mM Br-, 1.0 mM PMS, and 5 μL Co2+ were present initially. These products are known as disinfection by-products (DBPs) since they are formed in water disinfection processes. Formation of DBPs was even more significant in the absence of Co2+. The data indicate that both PMS and SO4- can transform Br- to reactive bromine species which react with NOM to form halogenated by-products. Less DBP formation in Co2+-PMS systems was due to the further destruction of DBPs by SO4-.
2.Designed protein aggregates entrapping carbon nanotubes for bioelectrochemical oxygen reduction.
Garcia KE1, Babanova S2, Scheffler W3, Hans M1, Baker D3, Atanassov P2, Banta S1. Biotechnol Bioeng. 2016 Apr 19. doi: 10.1002/bit.25996. [Epub ahead of print]
The engineering of robust protein/nanomaterial interfaces is critical in the development of bioelectrocatalytic systems. We have used computational protein design to identify two amino acid mutations in the small laccase protein (SLAC) from Streptomyces coelicolor to introduce new inter-protein disulfide bonds. The new dimeric interface introduced by these disulfide bonds in combination with the natural trimeric structure drive the self-assembly of SLAC into functional aggregates. The mutations had a minimal effect on kinetic parameters, and the enzymatic assemblies exhibited an increased resistance to irreversible thermal denaturation. The SLAC assemblies were combined with single-walled carbon nanotubes (SWNTs), and explored for use in oxygen reduction electrodes. The incorporation of SWNTs into the SLAC aggregates enabled operation an elevated temperature and reduced the reaction overpotential. A current density of 1.1 mA/cm2 at 0 V vs.
3.Ultrasensitive electrochemical DNAzyme sensor for lead ion based on cleavage-induced template-independent polymerization and alkaline phosphatase amplification.
Liu S1, Wei W2, Sun X2, Wang L2. Biosens Bioelectron. 2016 Apr 11;83:33-38. doi: 10.1016/j.bios.2016.04.026. [Epub ahead of print]
In this article, a simple, highly sensitive and selective electrochemical DNAzyme sensor for Pb2+ was developed on the basis of a 8-17 DNAzyme cleavage-induced template-independent polymerization and alkaline phosphatase amplification strategy. The hairpin-like substrate strand (HP DNA) of 8-17 DNAzyme was firstly immobilized onto the electrode. In the presence of Pb2+ and the catalytic strand of 8-17 DNAzyme, the HP DNA could be cleaved to expose the free 3'-OH terminal, which could be then utilized for the cascade operation by terminal deoxynucleotidyl transferase (TdTase) for the base extension to incorporate biotinylated dUTP (dUTP-biotin). The further conjugated streptavidin-labeled alkaline phosphatase (SA-ALP) then catalyzed conversion of electrochemically inactive 1-naphthyl phosphate (1-NP) for the generation of electrochemical response signal. The currently fabricated Pb2+ sensor effectively combines triply cascade amplification effects including cyclic Pb2+-dependent DNAzyme cleavage, TdTase-mediated base extension and enzymatic catalysis of ALP.
4.Folate/Folic Acid Knowledge, Intake, and Self-Efficacy of College-Age Women: Impact of Text Messaging and Availability of a Folic Acid-Containing Supplement.
Rampersaud GC1, Sokolow A1, Gruspe A1, Colee JC1, Kauwell GP1. J Am Coll Health. 2016 Apr 19:0. [Epub ahead of print]
OBJECTIVE: Evaluate the impact of educational text messages (TM) on folate/folic acid knowledge and consumption among college-age women, and to evaluate the impact of providing folic acid supplements on folate/folic acid intake among college-age women.