The dynamics of vortex generation in superfluid 3He-B

A profound change occurs in the stability of quantized vortices in externally applied flow of superfluid 3He-B at temperatures ~ 0.6 Tc, owing to the rapidly decreasing damping in vortex motion with decreasing temperature. At low damping an evolving vortex may become unstable and generate a new independent vortex loop. This single-vortex instability is the generic precursor to turbulence. We investigate the instability with non-invasive NMR measurements on a rotating cylindrical sample in the intermediate temperature regime (0.3 - 0.6) Tc. From comparisons with numerical calculations we interpret that the instability occurs at the container wall, when the vortex end moves along the wall in applied flow.Comment: revised & extended version. Journal of Low Temperature Physics, accepted (2008

The reliability of using the single-biopsy approach to assess basal muscle protein synthesis rates in vivo in humans.

It has recently been proposed that basal muscle protein synthesis can be effectively assessed by measuring the background enrichment in total plasma protein, thereby omitting the initial biopsy, and determining the difference in enrichment from a single muscle biopsy obtained during a primed continuous infusion of isotope-labeled amino acids. We determined the reliability of calculating basal mixed muscle protein fractional synthetic rates ( FSRs ) from mixed plasma proteins and a single muscle biopsy compared against the sequential muscle biopsy approach. Ten men ( age, 23 ± 1 years; body mass index, 22 ± 1 kg∙m−2 ) received muscle biopsies of the vastus lateralis after 2 and 4 hours of a primed continuous infusion of L-[ring-13C6]phenylalanine. Mixed muscle protein FSR was calculated from baseline plasma enrichments and muscle protein enrichments determined from the biopsy at 2 hours ( 1BX SHORT ) or 4 hours ( 1BX LONG ), or between muscle protein enrichments at 2 and 4 hours ( 2BX ) of the infusion. No differences ( P = .50 ) were observed in mixed muscle protein FSR, using plasma [ring-13C6]phenylalanine enrichments as the precursor, between the 1BX SHORT ( 0.031% ± 0.010%∙h−1 ), 1BX LONG ( 0.032% ± 0.007%∙h−1 ), or 2BX ( 0.035% ± 0.011%∙h−1 ) approach. A significant correlation was observed between the calculated muscle protein FSR assessed using the 1BX LONG and 2BX approach ( r = 0.7, P = .02 ). Our data demonstrate that the single-biopsy approach, irrespective of whether the biopsy is obtained at 2 or 4 hours, can be used as a surrogate for the sequential-biopsy approach to determine basal muscle protein synthesis in a group

The muscle protein synthetic response to carbohydrate and protein ingestion is not impaired in men with longstanding type 2 diabetes.

Protein ingestion stimulates muscle protein synthesis and improves net muscle protein balance. Insulin resistance has been suggested to result in a reduced muscle protein synthetic response to food intake. As such, we hypothesized that type 2 diabetes patients have a impaired muscle protein synthetic response to food ingestion. To test this hypothesis, 10 male type 2 diabetes patients using their normal oral glucose-lowering medication (68 +/- 2 y) and 10 matched, normoglycemic men (65 +/- 2 y) were randomly assigned to 2 crossover treatments in which whole body and muscle protein synthesis were measured following the consumption of either carbohydrate (CHO) or carbohydrate with a protein hydrolysate (CHO+PRO). Primed, continuous infusions with L-[ring-13C6]phenylalanine and L-[ring-2H2]tyrosine were applied and blood and muscle samples were collected to assess whole-body protein balance and mixed muscle protein fractional synthetic rate over a 6-h period. Whole-body phenylalanine and tyrosine flux were higher after the CHO+PRO treatment compared with the CHO treatment in the diabetes and control group (P <0.01). Protein balance was negative following CHO but positive following CHO+PRO treatment in both groups. Muscle protein synthesis rates were higher in both groups following the CHO+PRO (0.086 +/- 0.014%/h) treatment than in the CHO treatment (0.040 +/- 0.003%/h; P <0.01) with no difference between the diabetes patients and normoglycemic controls. We conclude that the muscle protein synthetic response to CHO or CHO+PRO ingestion is not substantially impaired in longstanding, type 2 diabetes patients treated with oral blood glucose-lowering medication

Protein ingestion before sleep improves postexercise overnight recovery.

RES, P. T., B. GROEN, B. PENNINGS, M. BEELEN, G. A. WALLIS, A. P. GIJSEN, J. M. G. SENDEN, and L. J. C. VAN LOON. Protein Ingestion before Sleep Improves Postexercise Overnight Recovery. Med. Sci. Sports Exerc., Vol. 44, No. 8, pp. 1560-1569, 2012. Introduction: The role of nutrition in modulating postexercise overnight recovery remains to be elucidated. We assessed the effect of protein ingestion immediately before sleep on digestion and absorption kinetics and protein metabolism during overnight recovery from a single bout of resistance-type exercise. Methods: Sixteen healthy young males performed a single bout of resistance-type exercise in the evening (2000 h) after a full day of dietary standardization. All subjects were provided with appropriate recovery nutrition (20 g of protein, 60 g of CHO) immediately after exercise (2100 h). Thereafter, 30 min before sleep (2330 h), subjects ingested a beverage with (PRO) or without (PLA) 40 g of specifically produced intrinsically [1-C-13] phenylalanine-labeled casein protein. Continuous intravenous infusions with [ring-H-2(5)] phenylalanine and [ring-H-2(2)] tyrosine were applied with blood and muscle samples collected to assess protein digestion and absorption kinetics, whole-body protein balance and mixed muscle protein synthesis rates throughout the night (7.5 h). Results: During sleep, casein protein was effectively digested and absorbed resulting in a rapid rise in circulating amino acid levels, which were sustained throughout the remainder of the night. Protein ingestion before sleep increased whole-body protein synthesis rates (311 +/- 8 vs 246 +/- 9 mu mol(.)kg(-1) per 7.5 h) and improved net protein balance (61 +/- 5 vs -11 +/- 6 mu mol(.)kg(-1) per 7.5 h) in the PRO vs the PLA experiment (P <0.01). Mixed muscle protein synthesis rates were similar to 22% higher in the PRO vs the PLA experiment, which reached borderline significance (0.059%(.)h(-1) +/- 0.005%(.)h(-1) vs 0.048%(.)h(-1) +/- 0.004%(.)h(-1), P = 0.05). Conclusions: This is the first study to show that protein ingested immediately before sleep is effectively digested and absorbed, thereby stimulating muscle protein synthesis and improving whole-body protein balance during postexercise overnight recovery

Protein co-ingestion stimulates muscle protein synthesis during resistance type exercise

In contrast to the impact of nutritional intervention on post-exercise muscle protein synthesis, little is known about the potential to modulate protein synthesis during exercise. This study investigates the impact of protein co-ingestion with carbohydrate on muscle protein synthesis during resistance type exercise. Ten healthy males were studied in the evening after consuming a standardized diet throughout the day. Subjects participated in 2 experiments, in which they ingested either carbohydrate or carbohydrate with protein during a 2h resistance exercise session. Subjects received a bolus of test drink prior to and every 15 min during exercise, providing 0.15 g.kg(-1).h(-1) carbohydrate with (CHO+PRO) or without (CHO) 0.15 g.kg(-1).h(-1) protein hydrolysate. Continuous intravenous infusions with L-[ring-(13)C6]phenylalanine and L-[ring-(2)H2] tyrosine were applied, and blood and muscle biopsies were collected to assess whole-body and muscle protein synthesis rates during exercise. Protein co-ingestion lowered whole-body protein breakdown rates by 8.4+/-3.6% (P=0.066), compared to the ingestion of carbohydrate only, and augmented protein oxidation and synthesis rates by 77+/-17 and 33+/-3%, respectively (P<0.01). As a consequence, whole-body net protein balance was negative in CHO, whereas a positive net balance was achieved following the CHO+PRO treatment (-4.4+/-0.3 vs 16.3+/-0.4 micromol phe.kg(-1).h(-1), respectively; P<0.01). In accordance, mixed muscle protein fractional synthetic rate (FSR) was 49+/-22% higher following protein co-ingestion (0.088+/-0.012 and 0.060+/-0.004 %.h(-1) in CHO+PRO vs CHO treatment, respectively; P<0.05). We conclude that, even in a fed state, protein co-ingestion stimulates whole-body and muscle protein synthesis rates during resistance type exercise. Key words: muscle, protein synthesis, exercise, nutrition

Coingestion of carbohydrate and protein hydrolysate stimulates muscle protein synthesis during exercise in young men, with no further increase during subsequent overnight recovery

We investigated the effect of carbohydrate and protein hydrolysate ingestion on whole-body and muscle protein synthesis during a combined endurance and resistance exercise session and subsequent overnight recovery. Twenty healthy men were studied in the evening after consuming a standardized diet throughout the day. Subjects participated in a 2-h exercise session during which beverages containing both carbohydrate (0.15 g x kg(-1) x h(-1)) and a protein hydrolysate (0.15 g x kg(-1) x h(-1)) (C+P, n = 10) or water only (W, n = 10) were ingested. Participants consumed 2 additional beverages during early recovery and remained overnight at the hospital. Continuous i.v. infusions with L-[ring-(13)C(6)]-phenylalanine and L-[ring-(2)H(2)]-tyrosine were applied and blood and muscle samples were collected to assess whole-body and muscle protein synthesis rates. During exercise, whole-body and muscle protein synthesis rates increased by 29 and 48% with protein and carbohydrate coingestion (P < 0.05). Fractional synthetic rates during exercise were 0.083 +/- 0.011%/h in the C+P group and 0.056 +/- 0.003%/h in the W group, (P < 0.05). During subsequent overnight recovery, whole-body protein synthesis was 19% greater in the C+P group than in the W group (P < 0.05). However, mean muscle protein synthesis rates during 9 h of overnight recovery did not differ between groups and were 0.056 +/- 0.004%/h in the C+P group and 0.057 +/- 0.004%/h in the W group (P = 0.89). We conclude that, even in a fed state, protein and carbohydrate supplementation stimulates muscle protein synthesis during exercise. Ingestion of protein with carbohydrate during and immediately after exercise improves whole-body protein synthesis but does not further augment muscle protein synthesis rates during 9 h of subsequent overnight recovery

An ALMA survey of submillimetre galaxies in the Extended Chandra Deep Field South: radio properties and the far-infrared/radio correlation

We present a study of the radio properties of 870 μm-selected submillimetre galaxies (SMGs), observed at high resolution with Atacama Large Millimeter Array (ALMA) in the Extended Chandra Deep Field South. From our initial sample of 76 ALMA SMGs, we detect 52 SMGs at >3σ significance in Karl G. Jansky Very Large Array 1400 MHz imaging, of which 35 are also detected at >3σ in new 610 MHz Giant Metre-Wave Radio Telescope imaging. Within this sample of radio-detected SMGs, we measure a median radio spectral index α1400610=−0.79±0.06, (with inter-quartile range α = [−1.16, −0.56]) and investigate the far-infrared/radio correlation via the parameter qIR, the logarithmic ratio of the rest-frame 8–1000 μm flux and monochromatic radio flux. Our median qIR = 2.56 ± 0.05 (inter-quartile range qIR = [2.42, 2.78]) is higher than that typically seen in single-dish 870 μm-selected sources (qIR ∼ 2.4), which may reflect the fact that our ALMA-based study is not biased to radio-bright counterparts, as previous samples were. Finally, we search for evidence that qIR and α evolve with age in a codependent manner, as predicted by starburst models: the data populate the predicted region of parameter space, with the stellar mass tending to increase along tracks of qIR versus α in the direction expected, providing the first observational evidence in support of these models

KISS: a spectrometric imager for millimetre cosmology

International audienceClusters of galaxies are used to map the large-scale structures in the universe and as probe of universe evolution. They can be observed through the Sunyaev-Zel’dovich (SZ) effect. In this respect the spectro-imaging at low resolution frequency is an important tool, today, for the study of cluster of galaxies. We have developed KISS (KIDs Interferometer Spectrum Survey), a spectrometric imager dedicated to the secondary anisotropies of the Cosmic Microwave Background (CMB). The multi-frequency approach permits to improve the component separation with respect to predecessor experiments. In this paper, firstly, we provide a description of the scientific context and the state of the art of SZ observations. Secondly, we describe the KISS instrument. Finally, we show preliminary results of the ongoing commissioning campaign

KISS: a spectrometric imager for millimetre cosmology

Clusters of galaxies are used to map the large-scale structures in the universe and as probe of universe evolution. They can be observed through the Sunyaev-Zel’dovich (SZ) effect. In this respect the spectro-imaging at low resolution frequency is an important tool, today, for the study of cluster of galaxies. We have developed KISS (KIDs Interferometer Spectrum Survey), a spectrometric imager dedicated to the secondary anisotropies of the Cosmic Microwave Background (CMB). The multi-frequency approach permits to improve the component separation with respect to predecessor experiments. In this paper, firstly, we provide a description of the scientific context and the state of the art of SZ observations. Secondly, we describe the KISS instrument. Finally, we show preliminary results of the ongoing commissioning campaign