3 research outputs found
Ponderomotive effects in multiphoton pair production
The Dirac-Heisenberg-Wigner formalism is employed to investigate
electron-positron pair production in cylindrically symmetric but otherwise
spatially inhomogeneous, oscillating electric fields. The oscillation
frequencies are hereby tuned to obtain multiphoton pair production in the
nonperturbative threshold regime. An effective mass as well as a
trajectory-based semi-classical analysis are introduced in order to interpret
the numerical results for the distribution functions as well as for the
particle yields and spectra. The results, including the asymptotic particle
spectra, display clear signatures of ponderomotive forces.Comment: 9 pages, 3 Tables, 3 Figure
Antidiabetic Potential of Purple and Red Rice (<i>Oryza sativa</i> L.) Bran Extracts
Pigmented
rice contains anthocyanins and proanthocyanidins that
are concentrated in the bran layer. In this study, we determined the
phenolic, flavonoid, anthocyanin, and proanthocyanidin content of
five rice bran (1 brown, 2 red, and 2 purple) extracts. Each bran
extract was evaluated for inhibitory effects on α-amylase and
α-glucosidase activity, two key glucosidases required for starch
digestion in humans. All purple and red bran extracts inhibited α-glucosidase
activity, however only the red rice bran extracts inhibited α-amylase
activity. Additionally, each bran extract was examined for their ability
to stimulate glucose uptake in 3T3-L1 adipocytes, a key function in
glucose homeostasis. Basal glucose uptake was increased between 2.3-
and 2.7-fold by exposure to the red bran extracts, and between 1.9-
and 3.1-fold by exposure to the purple bran extracts. In red rice
bran, the highest enzyme inhibition and glucose uptake was observed
with a proanthocyanidin-enriched fraction. Both IITA red bran and
IAC purple bran increased expression of GLUT1 and GLUT4 mRNA, and
genes encoding insulin-signaling pathway proteins
Glyceollin-Elicited Soy Protein Consumption Induces Distinct Transcriptional Effects As Compared to Standard Soy Protein
Glyceollins are stress-induced compounds in soybeans
with bioactive
properties distinct from parent soy isoflavones. The goals of this
study were to evaluate the effects of dietary glyceollin-enriched
and standard soy protein isolates and identify candidate target pathways
of glyceollins on transcriptional profiles within mammary gland tissue.
Thirty female postmenopausal cynomolgus monkeys were randomized to
diets containing one of three protein sources for 3 weeks: (1) control
casein/lactalbumin (C/L), (2) standard soy protein containing 194
mg/day isoflavones (SOY), and (3) glyceollin-enriched soy protein
containing 189 mg/day isoflavones + 134 mg/day glyceollins (GLY).
All diets contained a physiologic dose of estradiol (E2) (1 mg/day).
All doses are expressed in human equivalents scaled by caloric intake.
Relative to the control C/L diet, the GLY diet resulted in greater
numbers of differentially regulated genes, which showed minimal overlap
with those of SOY. Effects of GLY related primarily to pathways involved
in lipid and carbohydrate metabolism, including peroxisome proliferator-activated
receptor (PPAR)-γ and AMP-activated protein kinase (AMPK) signaling,
adipocytokine expression, triglyceride synthesis, and lipase activity.
Notable genes upregulated by the GLY diet included PPAR-γ, adiponectin,
leptin, lipin 1, and lipoprotein lipase. The GLY diet also resulted
in lower serum total cholesterol, specifically nonhigh-density lipoprotein
cholesterol, and increased serum triglycerides as compared to the
C/L diet. No effects of GLY or SOY were seen on serum insulin, adipocytokines,
or vascular and bone turnover markers. These preliminary findings
suggest that glyceollin-enriched soy protein has divergent effects
from standard soy with some specificity for adipocyte activity and
nutrient metabolism