83 research outputs found
Photooxygenation mechanisms in naproxen-amino acid linked systems
The photooxygenation of model compounds containing the two enantiomers of naproxen (NPX) covalently
linked to histidine (His), tryptophan (Trp) and tyrosine (Tyr) has been investigated by steady state
irradiation, fluorescence spectroscopy and laser flash photolysis. The NPXâHis systems presented the
highest oxygen-mediated photoreactivity. Their fluorescence spectra matched that of isolated NPX and
showed a clear quenching by oxygen, leading to a diminished production of the NPX triplet excited state
(
3
NPX*âHis). Analysis of the NPXâHis and NPXâTrp photolysates by UPLC-MSâMS revealed in both cases
the formation of two photoproducts, arising from the reaction of singlet oxygen (1
O2) with the amino acid
moiety. The most remarkable feature of NPXâTrp systems was a fast and stereoselective intramolecular
fluorescence quenching, which prevented the efficient formation of 3
NPX*âTrp, thus explaining their
lower reactivity towards photooxygenation. Finally, the NPXâTyr systems were nearly unreactive and
exhibited photophysical properties essentially coincident with those of the parent NPX. Overall, these
results point to a type II photooxygenation mechanism, triggered by generation of 1
O2 from the 3
NPX*
chromophoreFinancial support from the Spanish Government (CTQ2010-14882, JCI-2011-09926, Miguel Servet CP11/00154), from the EU (PCIG12-GA-2012-334257), from the Universitat Politecnica de Valencia (SP20120757) and from the Conselleria de Educacio, cultura i Esport (PROMETEOII/2013/005, GV/2013/051) is gratefully acknowledged.VayĂĄ PĂ©rez, I.; Andreu Ros, MI.; JimĂ©nez Molero, MC.; Miranda Alonso, MĂ. (2014). Photooxygenation mechanisms in naproxen-amino acid linked systems. Photochemical & Photobiological Sciences Photochemical and Photobiological Sciences. 13:224-230. https://doi.org/10.1039/c3pp50252jS22423013L. I. Grossweiner and K. C.Smith, Photochemistry, in The Science of Photobiology, ed. K. C. Smith, Plenum Press, New York, 2nd edn, 1989, pp. 47â78L. Pretali and A.Albini, in CRC Handbook of Organic Photochemistry and Photobiology, ed. A. Griesbeck, M. Oelgemöller and F. Ghetti, CRC Press, Boca Raton, FL, 3rd edn, 2012, pp. 369â391Foote, C. S. (1991). 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Pennsylvania Folklife Vol. 12, No. 3
âą Antiques in Dutchland âą Antique or Folk Art: Which? âą Pennsylvania Dutch âą Amish Barn Raisings âą Building a Pennsylvania Barn âą Water Witching âą Amish Family Life: A Sociologist\u27s Analysis âą Straw Hat Making Among the Old Order Amish âą Bread and Apple-Butter Day âą Schnitz in the Pennsylvania Folk-Culture âą Dutch Country Scarecrows âą The Man Who Was Buried Standing Up âą Living Occult Practices in Dutch Pennsylvania âą Farewell to Olliehttps://digitalcommons.ursinus.edu/pafolklifemag/1011/thumbnail.jp
Coupling of kinesin ATP turnover to translocation and microtubule regulation: one engine, many machines
The cycle of ATP turnover is integral to the action of motor proteins. Here we discuss how variation in this cycle leads to variation of function observed amongst members of the kinesin superfamily of microtubule associated motor proteins. Variation in the ATP turnover cycle among superfamily members can tune the characteristic kinesin motor to one of the range of microtubule-based functions performed by kinesins. The speed at which ATP is hydrolysed affects the speed of translocation. The ratio of rate constants of ATP turnover in relation to association and dissociation from the microtubule influence the processivity of translocation. Variation in the rate-limiting step of the cycle can reverse the way in which the motor domain interacts with the microtubule producing non-motile kinesins. Because the ATP turnover cycle is not fully understood for the majority of kinesins, much work remains to show how the kinesin engine functions in such a wide variety of molecular machines
Spectroscopy of Cu(II)-PcoC and the Multicopper Oxidase Function of PcoA, Two Essential Components of Escherichia coli pco
Safety and Performance of the Omnipod Hybrid Closed-Loop System in Adults, Adolescents, and Children with Type 1 Diabetes over 5 Days under Free-Living Conditions
Background: The objective of this study was to assess the safety and performance of the Omnipod\uae personalized model predictive control (MPC) algorithm in adults, adolescents, and children aged 656 years with type 1 diabetes (T1D) under free-living conditions using an investigational device. Materials and Methods: A 96-h hybrid closed-loop (HCL) study was conducted in a supervised hotel/rental home setting following a 7-day outpatient standard therapy (ST) phase. Eligible participants were aged 6-65 years with A1C <10.0% using insulin pump therapy or multiple daily injections. Meals during HCL were unrestricted, with boluses administered per usual routine. There was daily physical activity. The primary endpoints were percentage of time with sensor glucose <70 and 65250 mg/dL. Results: Participants were 11 adults, 10 adolescents, and 15 children aged (mean \ub1 standard deviation) 28.8 \ub1 7.9, 14.3 \ub1 1.3, and 9.9 \ub1 1.0 years, respectively. Percentage time 65250 mg/dL during HCL was 4.5% \ub1 4.2%, 3.5% \ub1 5.0%, and 8.6% \ub1 8.8% per respective age group, a 1.6-, 3.4-, and 2.0-fold reduction compared to ST (P = 0.1, P = 0.02, and P = 0.03). Percentage time <70 mg/dL during HCL was 1.9% \ub1 1.3%, 2.5% \ub1 2.0%, and 2.2% \ub1 1.9%, a statistically significant decrease in adults when compared to ST (P = 0.005, P = 0.3, and P = 0.3). Percentage time 70-180 mg/dL increased during HCL compared to ST, reaching significance for adolescents and children: HCL 73.7% \ub1 7.5% vs. ST 68.0% \ub1 15.6% for adults (P = 0.08), HCL 79.0% \ub1 12.6% vs. ST 60.6% \ub1 13.4% for adolescents (P = 0.01), and HCL 69.2% \ub1 13.5% vs. ST 54.9% \ub1 12.9% for children (P = 0.003). Conclusions: The Omnipod personalized MPC algorithm was safe and performed well over 5 days and 4 nights of use by a cohort of participants ranging from youth aged 656 years to adults with T1D under supervised free-living conditions with challenges, including daily physical activity and unrestricted meals
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