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Absorptive State

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Avery D Faigenbaum – One of the best experts on this subject based on the ideXlab platform.

  • Thermogenic effect of an acute ingestion of a weight loss supplement
    Journal of the International Society of Sports Nutrition, 2009
    Co-Authors: Jay R Hoffman, Jie Kang, Nicholas A Ratamess, Stefanie L Rashti, Christopher P Tranchina, Avery D Faigenbaum

    Abstract:

    Background The purpose of this study was to examine the acute effects of a weight loss supplement on resting oxygen uptake (VO_2), respiratory quotient (RQ), caloric expenditure (kcal), heart rate (HR), and blood pressure (BP) in healthy and physically active individuals. Methods Ten subjects (5 male, 5 female; 20.2 ± 1.2 y; 172.2 ± 8.9 cm; 71.5 ± 17.2 kg; 17.3 ± 2.6% body fat) underwent two testing sessions administered in a randomized and double-blind fashion. During each session, subjects reported to the Human Performance Laboratory after at least 3-h post-Absorptive State and were provided either 3 capsules of the weight loss supplement (SUP), commercially marketed as Meltdown^® or 3 capsules of a placebo (P). Subjects then rested in a semi-recumbent position for three hours. VO_2 and HR were determined every 5 min during the first 30 min and every 10 min during the next 150 min. BP was determined every 15 min during the first 30 min and every 30 min thereafter. The profile of mood States was assessed every 30 min. Results Area under the curve analysis revealed a significant 28.9% difference in VO_2 between SUP and P for the three hour study period. In addition, a significant difference in energy expenditure was also seen between SUP (1.28 ± 0.33 kcal·min^-1) and P (1.00 ± 0.32 kcal·min^-1). A trend (p = 0.06) towards a greater utilization of stored fat as an energy source was also demonstrated (0.78 ± 0.23 kcal·min^-1 and 0.50 ± 0.38 kcal·min^-1 in P and SUP, respectively). Significant elevations in HR were seen during hours two and three of the study, and significantly higher average systolic BP was observed between SUP (118.0 ± 7.3 mmHg) and P (111.4 ± 8.2 mmHg). No significant differences were seen in diastolic blood pressure at any time point. Significant increases in tension and confusion were seen in SUP. Conclusion Results indicate a significant increase in energy expenditure in young, healthy individuals following an acute ingestion of a weight loss supplement. In addition, ingestion of this supplement appears modify mood and elevate HR and systolic BP following ingestion.

  • Thermogenic Effect from Nutritionally Enriched Coffee Consumption
    Journal of the International Society of Sports Nutrition, 2006
    Co-Authors: Jay R Hoffman, Jie Kang, Nicholas A Ratamess, Peter F Jennings, Gerald Mangine, Avery D Faigenbaum

    Abstract:

    Background The purpose of this study was to examine the effect of nutritionally enriched JavaFit™ (JF) coffee (450 mg of caffeine, 1200 mg of garcinia cambogia, 360 mg of citrus aurantium extract, and 225 mcg of chromium polynicotinate) on resting oxygen uptake (VO_2), respiratory exchange ratio (RER), heart rate (HR), and blood pressure (BP) in healthy and physically active individuals. Method Ten subjects (8 male, 2 female; 20.9 ± 1.7 y; 178.1 ± 10.4 cm; 71.8 ± 12.1 kg) underwent two testing sessions administered in a randomized and double-blind fashion. During each session, subjects reported to the Human Performance Laboratory after at least 3-h post-Absorptive State and were provided either 354 ml (1.5 cups) of freshly brewed JF or commercially available caffeinated coffee (P). Subjects then rested in a semi-recumbent position for three hours. VO_2 and HR were determined every 5 min during the first 30 min and every 10 min during the next 150 min. BP was determined every 15 min during the first 30 min and every 30 min thereafter. Area under the curve (AUC) analysis was computed for VO_2, whereas a session-average was calculated for RER, HR and BP. Results Initial analysis revealed no significant differences. However, seven of the ten subjects were considered responders to JF (had a higher AUC for VO_2during JF than P). Statistical analysis showed the difference between JF and P (12%) to be significantly different in these responders. In addition, the average systolic BP was higher (p < 0.05) in JF (118 ± 7 mmHg) than P (115 ± 8 mmHg) in both the total sample and the subgroup of responders. No differences in average HR and average diastolic BP were observed between JF and P in both the total sample and the subgroup of responders. Conclusion It appears that consuming a nutritionally-enriched coffee beverage may increase resting energy expenditure in individuals that are sensitive to the caffeine and herbal coffee supplement. In addition, this supplement also appears to affect cardiovascular dynamics by augmenting systolic arterial blood pressure.

Pascal Haberey – One of the best experts on this subject based on the ideXlab platform.

  • erythrocytes participate significantly in blood transport of amino acids during the post Absorptive State in normal humans
    European Journal of Applied Physiology, 1998
    Co-Authors: Abdelnacer Agli, A Schaefer, Bernard Geny, Francois Piquard, Pascal Haberey

    Abstract:

    To investigate the participation of erythrocytes in the blood transport of amino acids during the course of intestinal absorption in humans, erythrocyte and plasma amino-acid concentrations were determined following ingestion of an oral load of amino acids. In addition to baseline plasma and erythrocyte amino acid concentrations in 18 subjects, plasma and erythrocyte amino acids kinetics during the 125 min following an oral amino acid load were further determined in 9 of the 18 subjects. The results showed that human erythrocytes contained most amino acids at similar or higher concentrations than plasma. Furthermore, the correlations observed between plasma and erythrocyte contents clearly indicated that erythrocytes were involved in the transport of amino acids by the blood. For some amino acids erythrocyte transport sometimes exceeded that of plasma. Significant correlation coefficients showed that strong plasma-erythrocyte relationships existed for alanine, valine, methionine, isoleucine, leucine, phenylalanine, and ornithine. In conclusion, our data supported the hypothesis that both blood compartments, plasma and erythrocytes, are involved significantly in the blood transport of amino acids in humans during the postAbsorptive State.

Alan Jenkins – One of the best experts on this subject based on the ideXlab platform.

  • A Fast Switching, High Isolation Absorptive SPST SiGe Switch for 24GHz Automotive Applications
    2003 33rd European Microwave Conference, 2003
    Co-Authors: Ian Gresham, Alan Jenkins

    Abstract:

    Measured results for a high isolation, extremely fast switching SPST SiGe switch are presented. The switch provides ~35dB of isolation between input and output over 15GHz-26GHz, yet is only 500μm × 250μm in size. A novel load circuit ensures that there is almost no perceptible change in the input reflection coefficient of the switch between the transmission and the Absorptive State. In the transmit State the switch provides gain for the input signal between 14.2GHz and 25.5GHz, and has a 1dB loss bandwidth of over 12GHz. Lastly, the use of a constant current biasing scheme allows extremely fast switching between States allowing the switch to be used to generate RF pulses of 200pS in length at a carrier frequency of 24GHz, with rise and fall times of approximately 60pS. The entire switch, including biasing circuitry, requires only 12mA from a +5V supply.

  • A fast switching, high isolation Absorptive SPST SiGe switch for 24 GHz automotive applications
    33rd European Microwave Conference Proceedings (IEEE Cat. No.03EX723C), 2003
    Co-Authors: Ian Gresham, Alan Jenkins

    Abstract:

    Measured results for a high isolation, extremely fast switching SPST SiGe switch are presented. The switch provides /spl sim/35 dB of isolation between input and output over 15 GHz-26 GHz, yet is only 500 /spl mu/m/spl times/250 /spl mu/m in size. A novel load circuit ensures that there is almost no perceptible change in the input reflection coefficient of the switch between the transmission and the Absorptive State. In the transmit State the switch provides gain for the input signal between 14.2 GHz and 25.5 GHz, and has a 1dB loss bandwidth of over 12 GHz. Lastly, the use of a constant current biasing scheme allows extremely fast switching between States allowing the switch to be used to generate RF pulses of 200 pS in length at a carrier frequency of 24 GHz, with rise and fall times of approximately 60 pS. The entire switch, including biasing circuitry, requires only 12 mA from a +5 V supply.