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Tatu A Miettinen - One of the best experts on this subject based on the ideXlab platform.
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cholesterol in vegetarians: effects of cholesterol feeding13
2016Co-Authors: Maui Vuoristo, Tatu A MiettinenAbstract:ABSTRACT Serum concentrations and metabolism of cho-lesterol were studied in vegetarians basally and during a dietary cholesterol load. Cholesterol Absorption Efficiency was normal and synthesis was slightly enhanced, even though serum choles-terol precursors were not increased. The serum concentrations of total and low-density-lipoprotein cholesterol were decreased pro-portionally to the reduced intake and absolute Absorption of cho-lesterol. Fecal plant sterols were negatively correlated with the Absorption Efficiency ofcholesterol and positively with fecal ster-ols and cholesterol synthesis, suggesting interference of high plant sterol intakes with cholesterol Absorption. Cholesterol sat-uration and bile acid composition of the bile were not changed. The increased serum plant sterol-cholesterol ratios were posi-tively related to the intake and negatively to the biliary secretion of plant sterols. Cholesterol feeding increased absolute choles-terol Absorption and serum concentrations of total and low-den-sity-lipoprotein cholesterol, did not change Absorption Efficiency or synthesis of cholesterol, but increased fecal cholestanol excretion. Am J Clin Nutr l994;59:l325-3l. KEY WORDS Vegetarians, serum lipoproteins, cholestero
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diabetes contributes to cholesterol metabolism regardless of obesity
Diabetes Care, 2002Co-Authors: Piia Simonen, Helena Gylling, Tatu A MiettinenAbstract:OBJECTIVE—To investigate cholesterol metabolism in obesity with and without diabetes. RESEARCH DESIGN AND METHODS—We performed cross-sectional metabolic studies in obese individuals with and without type 2 diabetes. The study population consisted of 16 obese (BMI >30 kg/m2) diabetic subjects with a mean age of 52 ± 2 years (SE) and 16 nondiabetic control subjects of similar age and weight. Cholesterol Absorption Efficiency was measured with peroral dual isotopes and cholesterol synthesis with sterol balance. RESULTS—Serum total cholesterol did not differ between the groups, but LDL and HDL cholesterol were significantly lower and VLDL cholesterol and serum total and VLDL triglycerides were higher in the diabetic group than in the control group. Cholesterol Absorption Efficiency was 29 ± 1% in diabetic subjects vs. 42 ± 2% in the control subjects (P CONCLUSIONS—Cholesterol Absorption Efficiency was lower and cholesterol synthesis was higher in obese subjects with diabetes than in those without diabetes, suggesting that diabetes modulates cholesterol metabolism more than obesity alone.
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cholesterol Absorption Efficiency and sterol metabolism in obesity
Atherosclerosis, 2000Co-Authors: Tatu A Miettinen, Helena GyllingAbstract:Abstract Role of enterohepatic cholesterol metabolism in obesity-induced increase of cholesterol synthesis was studied in healthy lean (BMI 31) subjects by measuring serum lipids (including plant sterols, cholestanol and cholesterol precursors), cholesterol Absorption % (double-label method), sterol balance and biliary lipids. New aspects of sterol metabolism in obesity were as follows: low Efficiency of cholesterol Absorption, reduced ratios to cholesterol of serum and biliary plant sterols and cholestanol (5α-derivative of cholesterol), and a marked increase of serum and biliary cholesterol precursor sterols. Percent of cholesterol Absorption was positively related to serum cholestanol and plant sterols, and negatively to cholesterol synthesis, measured by the sterol balance technique or cholesterol precursor sterols in serum or bile. Total and endogenous cholesterol fluxes into the intestine were increased, but owing to low Absorption percent, mass of cholesterol Absorption was within control limits in the obese subjects. Thus, per gram of their large liver tissue the entry of intestinal cholesterol may even be subnormal. Percent of cholesterol Absorption was insignificantly negatively ( r =−0.256) related to intestinal cholesterol pool, but significantly to biliary concentrations of cholesterol ( r =−0.581), bile acids ( r =−0.513) and phospholipids ( r =−0.469). Thus, dilution of labeled dietary cholesterol by expanded intestinal cholesterol pool could have contributed to subnormal Efficiency of cholesterol Absorption, or transfer of labeled dietary cholesterol from intestinal oil phase to micellar phase may be competitively inhibited by expanded biliary secretion, resulting in reduced Absorption of dietary cholesterol. These mechanisms could have contributed to changes in metabolism of non-cholesterol sterols, especially of cholestanol and plant sterols.
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adaptation of cholesterol Absorption after proximal resection of porcine small intestine
Journal of Lipid Research, 1996Co-Authors: Mikko P Pakarinen, Tatu A Miettinen, Jouni Lauronen, Pekka Kuusanmaki, Peter Raivio, T Kivisto, Jorma HalttunenAbstract:Cholesterol Absorption occurs primarily in the upper small intestine. Our aim was to assess Absorption of cholesterol during ileal adaptation after proximal small intestinal resection. In vivo Absorption and elimination of cholesterol, plasma cholesterol, cholesterol precursors, and plant sterols were related to intestinal morphology and transit 4 (n = 5), 8 (n = 5), and 14 (n = 5) weeks after a 75% proximal resection of porcine small intestine, and compared to preoperative (n = 5) and transected (n = 5) control animals. Fractional cholesterol Absorption, the daily amount of cholesterol absorbed, plasma cholesterol, and plant sterol to cholesterol proportions were significantly (P < 0.05 or less) decreased, whereas fecal loss of cholesterol as neutral steroids, less so as bile acids, plasma cholesterol precursor proportions, and ileal mass and villus height were significantly increased (P < 0.05 or less) after 8 weeks of the resection. Cholesterol Absorption Efficiency, decreased by the resection, was gradually increased from 5.4 +/- 2.2 to 26.9 +/- 3.9% during the 14 postoperative weeks (P < 0.0001) simultaneously with a 46% increase in villus height compared with transection (P < 0.0001), but Absorption remained still below control levels (80.4 +/- 2.5%, P < 0.0001). In resected and control animals, villus height correlated positively with cholesterol Absorption Efficiency (r = 0.85, P < 0.0001; r = 0.76, P = 0.01) and plasma plant sterol proportions (r = 0.94-0.95, P < 0.0001; r = 0.78-0.85, P < 0.008), respectively. In conclusion, after massive proximal small bowel resection, adaptation of intestinal cholesterol Absorption Efficiency occurs in the distal ileum closely parlleling villus hypertrophy.
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inhibition of cholesterol Absorption by hmg coa reductase inhibitor
European Journal of Clinical Pharmacology, 1991Co-Authors: Tatu A MiettinenAbstract:In subjects with familial hypercholesterolemia cholesterol Absorption Efficiency was insignificantly reduced during a short-term more consistently during long-term pravastatin treatment. A cholesterol feeding had no effect on LDL cholesterol level but reduced Absorption Efficiency during a long-term lovastatin treatment.
Paiyen Chen - One of the best experts on this subject based on the ideXlab platform.
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dielectric antireflection fiber arrays for Absorption enhancement in thin film organic tandem solar cells
IEEE Journal of Selected Topics in Quantum Electronics, 2016Co-Authors: Jing Bai, Paiyen ChenAbstract:Effort to improve the bulk heterojunction organic solar cells’ Absorption Efficiency utilizes tandem structures combining low- and high-bandgap absorbing polymers so that a broader spectrum of sunlight's energy can be used for the photon-to-electron conversion and the thermalization loss of photon energy can be reduced. However, at the intersection of the upper energy level of the high-bandgap polymer and the lower energy level of the low-bandgap polymer, photon Absorption Efficiency remains low due to the destructive interference of these energy states at the band edges. In order to circumvent this issue, we theoretically propose using dielectric fiber arrays to generate lensing effects atop of a thin-film polymer/organic tandem solar cell (OTSC), aiming to enhance its optical Absorption Efficiency. Dielectric fibers have been calibrated to generate the optimal antireflection coating resulting in an integrated Absorption enhancement up to 11% compared to its flat-OTSC counterpart. The overall integrated AM1.5 G (air mass 1.5 global simulated solar spectra) Absorption yields Absorption efficiencies of 83% in an optimal configuration, with a cell size of 600 nm and fiber radius of 150 nm. By using fibers as focusing lenses/antireflectors, we demonstrate that there exists zero reflection at multiple visible frequencies, leading to a relative broadband Absorption of an ultrathin substrate.
Christopher M Pearce - One of the best experts on this subject based on the ideXlab platform.
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ingestion rate Absorption Efficiency oxygen consumption and fecal production in green sea urchins strongylocentrotus droebachiensis fed waste from sablefish anoplopoma fimbria culture
Aquaculture, 2014Co-Authors: Lindsay C Orr, Daniel L Curtis, Stephen F Cross, Helen Gurneysmith, Alynn Shanks, Christopher M PearceAbstract:Abstract The ability of the green sea urchin (Strongylocentrotus droebachiensis) to consume and subsequently reduce the organic content of sablefish (Anoplopoma fimbria) culture waste was assessed and properties influencing the dispersal of fecal pellets egested by the sea urchins were quantified in laboratory trials. Ingestion rate, Absorption Efficiency, and oxygen uptake in sea urchins and the shape, size, and settling velocity of fecal pellets were determined for individuals fed sablefish waste or a natural control diet (giant kelp, Macrocystis pyrifera). Results showed that S. droebachiensis consumes sablefish waste at a dry weight ingestion rate of 0.43 ± 0.039 g individual− 1 d− 1 and absorbs 40 ± 4.84% (mean ± SE) of the organic material ingested, with no significant (P
Bikkina Srinivas - One of the best experts on this subject based on the ideXlab platform.
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mass Absorption Efficiency of light absorbing organic aerosols from source region of paddy residue burning emissions in the indo gangetic plain
Atmospheric Environment, 2016Co-Authors: Bikkina Srinivas, M M Sarin, Neeraj Rastogi, Atinderpal Singh, Darshan SinghAbstract:Abstract The mass Absorption Efficiency (MAE) of light absorbing water-soluble organics, representing a significant fraction of brown carbon (BrC), has been studied in fine mode aerosols (PM2.5) from a source region (Patiala: 30.2 °N, 76.3 °E) of biomass burning emissions (BBEs) in the Indo-Gangetic Plain (IGP). The mass Absorption coefficient of BrC at 365 nm (babs-365), assessed from Absorption spectra of aqueous extracts, exhibits significant linear relationship with water-soluble organic carbon (WSOC) for day (R2 = 0.37) and night time (R2 = 0.77) samples; and slope of regression lines provides a measure of MAE of BrC (daytime: ∼0.75 m2 g−1 and night time: 1.13 m2 g−1). A close similarity in the temporal variability of babs-365 (for BrC) and K+ in all samples suggests their common source from BBEs. The babs-365 of BrC follows a power law (babs-λ ≈ λ−α; where α = angstrom exponent) and averages around 5.2 ± 2.0 M m−1 (where M = 10−6). A significant decrease in the MAE of BrC from the source region (this study) to the downwind oceanic region (over Bay of Bengal, Srinivas and Sarin, 2013 ) could be attributed to relative increase in the contribution of non-absorbing WSOC and/or photo-bleaching of BrC during long-range atmospheric transport. The atmospheric radiative forcing due to BrC over the study site accounts for ∼40% of that from elemental carbon (EC).
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brown carbon in atmospheric outflow from the indo gangetic plain mass Absorption Efficiency and temporal variability
Atmospheric Environment, 2014Co-Authors: Bikkina Srinivas, M M SarinAbstract:The simultaneous measurements of brown carbon (BrC) and elemental carbon (EC) are made in ambient aerosols (PM2.5), collected from a site in north-east India during November'09–March'10, representing the atmospheric outflow from the Indo-Gangetic Plain (IGP) to the Bay of Bengal (BoB). The Absorption coefficient of BrC (babs), assessed from water-soluble organic carbon (WSOC) at 365 nm, varies from 2 to 21 M m−1 and exhibits significant linear relationship (P < 0.05) with WSOC concentration (3–29 μg m−3). The angstrom exponent (α: 8.3 ± 2.6, where babs ≈ λ−α.) is consistent with that reported for humic-like substances (HULIS) from biomass burning emissions (BBE). The impact of BBE is also discernible from mass ratios of nss-K+/EC (0.2–1.4) and OC/EC (3.4–11.5). The mass fraction of WSOC (10–23%) in PM2.5 and mass Absorption Efficiency of BrC (σabs-BrC: 0.5–1.2 m2 g−1) bring to focus the significance of brown carbon in atmospheric radiative forcing due to anthropogenic aerosols over the Indo-Gangetic Plain.
Jung Hyeun Kim - One of the best experts on this subject based on the ideXlab platform.
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Controlled phase separation in flexible polyurethane foams with diethanolamine cross-linker for improved sound Absorption Efficiency
International Journal of Precision Engineering and Manufacturing-Green Technology, 2016Co-Authors: Seok Kyeong Kim, Giwook Sung, Jae Gyoung Gwon, Jung Hyeun KimAbstract:For comfortable driving conditions, flexible polyurethane (PU) foams are used for sound absorbers in noise, vibration, harshness (NVH) systems. The cellular structures of PU foams are important to improve the sound Absorption Efficiency, and the cell morphology is strongly dependent the use of experimental ingredients such as catalysts and cross-linking agents. Uniform cavity size distribution is achieved by controlling the catalyst ratio between gelling and blowing catalysts, and the optimum catalyst ratio (9:1) is used with a diethanolamine (DEA) cross-linker for improved sound Absorption Efficiency. DEA affects pore morphology by preventing phase separation in PU matrix, and the number of open pores reduces with increasing DEA contents. Sound Absorption coefficient shows the highest at 9:1 catalyst ratio and 0.9 g DEA usage in the flexible PU foams under disturbed phase separation conditions.
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sound Absorption behavior of flexible polyurethane foams with distinct cellular structures
Materials & Design, 2016Co-Authors: Jae Gyoung Gwon, Seok Kyeong Kim, Jung Hyeun KimAbstract:Abstract The effect of cellular structure in the flexible polyurethane foams on the sound Absorption behavior is investigated for improved sound environment within vehicles. Two types of gelling catalyst and water are used for producing well-defined cavity and pore structure in the foams. The catalyst, having high activity in urethane reaction, produces a larger number of small cavities and pores in the foams compared to the catalyst having low activity. A high number of small cavities can also be obtained at high water content from the restraint of neighboring cavities due to actively formed urethane matrix. The foam density decreases with increasing water and catalyst contents. Sound Absorption Efficiency is usually low at low foam density, but the results show improved sound Absorption Efficiency even at the reduced foam density because of the high number of well dispersed small cells in the foams.
