Intestinal folate transport has been well characterized, and rat small intestinal epithelial (IEC-6) cells have been used as a model system for the study of this process on the cellular level. The major intestinal folate transport activity has a low-pH optimum, and the current paradigm is that this process is mediated by the reduced folate carrier (RFC), despite the fact that this carrier has a...

Although efforts have been made to develop a platform carrier for the delivery of RNAi therapeutics, systemic delivery of siRNA has shown only limited success in cancer therapy. Cationic lipid-based nanoparticles have been widely used for this purpose, but their toxicity and undesired liver uptake after systemic injection owing to their cationic surfaces have hampered further clinical translati...

L-Kynurenine (KYN), an intermediary product in the kynurenine pathway of tryptophan metabolism, is the common precursor from which are formed both quinolinic acid, a potent endogenous "excitotoxin," and kynurenic acid, a nonselective antagonist of excitotoxins. The present work examines 3H-KYN transport in primary astrocyte cultures derived from the cerebra of newborn mice. Influx and efflux of...

Lysosomal membrane vesicles isolated from rat liver were exploited to analyze the mechanism of glucose transport across the lysosomal membrane. Uptake kinetics of [14C]D-glucose showed a concentration-dependent saturable process, typical of carrier-mediated facilitated transport, with a Kt of about 75 mM. Uptake was unaffected by Na+ and K+ ions, membrane potentials, and proton gradients but sh...

The Neutral Point Clamped (NPC) three-level inverter with Z-source network is a relatively recent converter topology that exhibits both voltage-buck and voltage-boost capability. This concept can be applied to all acto-ac, dc-to-dc, ac-to-dc, and dc-to-ac power conversion whether two-level or multilevel. However, multilevel inverters offer many benefits for higher power applications. Existing p...

Balancing control of neutral-point voltage (NPV) and reducing common-mode (CMV) are crucial for a three-level neutral-point-clamped (NPC) inverter. NPV oscillation can be inhibited by constructing virtual vectors adding adjustment factors to eliminate stochastic disturbances that cause unbalanced NPV. However, the significantly increase computational complexity introduce dynamic sector split in...

Cationic liposomes are frequently used as carrier particles for nucleic acid delivery. The most popular formulation is the equimolar mixture of two components, a cationic lipid and a neutral phosphoethanolamine. Its uptake pathway has been described as endocytosis. The presence of an aromatic molecule as a third component strongly influences the cellular uptake process and results in complete m...

We report double-resonant IR/UV ion-dip spectroscopy of neutral gramicidin peptides in the gas phase. The IR spectra of gramicidin A and C, recorded in both the 1000 cm(-1) to 1800 cm(-1) and the 2700 to 3750 cm(-1) region, allow structural analysis. By studying this broad IR range, various local intramolecular interactions are probed, and complementary IR modes can be accessed. Ab initio quant...

We present a detailed investigation into the optical characteristics of individual InAs quantum dots QDs grown by metalorganic chemical vapor deposition, with low temperature emission in the telecoms window around 1300 nm. Using microphotoluminescence PL spectroscopy we have identified neutral, positively charged, and negatively charged exciton and biexciton states. Temperature-dependent measur...