3,241 research outputs found
Does skeletal muscle carnitine availability influence fuel selection during exercise?
No full textThis is the author accepted manuscript. The final version is available from Cambridge University Press via the DOI in this record.Fat and carbohydrate are the major fuel sources utilised for oxidative, mitochondrial ATP resynthesis during human skeletal muscle contraction. The relative contribution of these two substrates to ATP resynthesis and total energy expenditure during exercise can vary substantially, and is predominantly determined by fuel availability and exercise intensity and duration. For example, the increased ATP demand that occurs with an increase in exercise intensity is met by increases in both fat and carbohydrate oxidation up to an intensity of approximately 60–70 % of maximal oxygen consumption. When exercise intensity increases beyond this workload, skeletal muscle carbohydrate utilisation is accelerated, which results in a reduction and inhibition of the relative and absolute contribution of fat oxidation to total energy expenditure. However, the precise mechanisms regulating muscle fuel selection and underpinning the decline in fat oxidation remain unclear. This brief review will primarily address the theory that a carbohydrate flux-mediated reduction in the availability of muscle carnitine to the mitochondrial enzyme carnitine palmitoyltransferase 1, a rate-limiting step in mitochondrial fat translocation, is a key mechanism for the decline in fat oxidation during high-intensity exercise. This is discussed in relation to recent work in this area investigating fuel metabolism at various exercise intensities and taking advantage of the discovery that skeletal muscle carnitine content can be nutritionally increased in vivo in human subjects
Parents studying medicine : the dichotomy of studying with a family
No full textIntroduction: In this article the personal study and life situation of parents who are also medical students at the Medical School of the Goethe University Frankfurt am Main is discussed. There is a special focus on the topics "studying with children" and "family-friendly university", which have been present in discussions about university development and in the daily life of academics, especially during the last decade. The workgroup "Individual Student Services" at the medical faculty at the Goethe University tries to meet the necessities of the individual study courses and to support the study success with a new counselling and student service concept.
Methods: The experience of parents studying medicine was recorded in semi-structured interviews (Date: April 2010), which were held as part of the sponsored pilot project on part-time medical studies ("Pilot Project Part-time Medical Studies"). Additionally, study results from the Medical School of the Goethe University Frankfurt am Main were integrated as well as a literature analysis.
Results: It was found that the teaching demands and support services, which have been suggested and needed for years now, have been partially implemented and are without sufficient support at the faculty level to date. Thus the current situation of medical students with children is still difficult and seems a big challenge for everyone involved.
Solution: As part of the "Individual Student Services" a new pilot project on part-time medical studies was established in November 2009. Only the use of new, unconventional and innovative ideas allows universities to adequately support the changing and heterogeneous student population and support them to successfully completing their medical studies
Interpretations and implications of the top quark rapidity asymmetries A(FB)(t) and A(FB)(l)
No full textForward-backward asymmetries A(FB)(t) and A(FB)(l) are observed in the top-quark t rapidity distribution and in the rapidity distribution of charged leptons l from top-quark decay at the Tevatron proton-antiproton collider, and a charge asymmetry A(C) is seen in proton-proton collisions at the Large Hadron Collider (LHC). In this paper, we update our previous studies of the Tevatron asymmetries using the most recent data. We provide expectations for AC at the LHC based first on simple extrapolations from the Tevatron, and second based on new physics models that can explain the Tevatron asymmetries. We examine the relationship of the two asymmetries A(FB)(t) and A(FB)(l). We show their connection through the (V - A) spin correlation between the charged lepton and the top quark with different polarization states. We show that the ratio of the two asymmetries provides independent insight into the physics interpretation of the top-quark asymmetry. We emphasize the value of the measurement of both asymmetries, and we conclude that a model which produces more right-handed than left-handed top quarks is suggested by the present Tevatron data.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000322145600004&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Astronomy & AstrophysicsPhysics, Particles & FieldsSCI(E)7ARTICLE1null8
Rebuttal from Marlou L. Dirks, Benjamin T. Wall and Francis B. Stephens
No full textThis article is part of a CrossTalk debate. Click the links to read the other articles in this debate: https://doi.org/10.1113/JP278219, https://doi.org/10.1113/JP279714, https://doi.org/10.1113/JP27822
Top Quark Production Asymmetries A(FB)(t) and A(FB)(l)
No full textA large forward-backward asymmetry is seen in both the top quark rapidity distribution A(FB)(t) and in the rapidity distribution of charged leptons A(FB)(l) from top quarks produced at the Tevatron. We study the kinematic and dynamic aspects of the relationship of the two observables arising from the spin correlation between the charged lepton and the top quark with different polarization states. We emphasize the value of both measurements, and we conclude that a new physics model which produces more right-handed than left-handed top quarks is favored by the present data.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000300247100002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Physics, MultidisciplinarySCI(E)EI20ARTICLE6null10
Depolarization and decreased surface expression of K+ channels contribute to NSAID-inhibition of intestinal restitution
No full textNon-steroidal anti-inflammatory drugs (NSAIDs) contribute to gastrointestinal ulcer formation by inhibiting epithelial cell migration and mucosal restitution; however, the drug-affected signaling pathways are poorly defined. We investigated whether NSAID inhibition of intestinal epithelial migration is associated with depletion of intracellular polyamines, depolarization of membrane potential (Em) and altered surface expression of K+ channels. Epithelial cell migration in response to the wounding of confluent IEC-6 and IEC-Cdx2 monolayers was reduced by indomethacin (100μM), phenylbutazone (100μM) and NS-398 (100μM) but not by SC-560 (1μM). NSAID-inhibition of intestinal cell migration was not associated with depletion of intracellular polyamines. Treatment of IEC-6 and IEC-Cdx2 cells with indomethacin, phenylbutazone and NS-398 induced significant depolarization of Em, whereas treatment with SC-560 had no effect on Em. The Em of IEC-Cdx2 cells was: −38.5±1.8mV under control conditions; −35.9±1.6mV after treatment with SC-560; −18.8±1.2mV after treatment with indomethacin; and −23.7±1.4mV after treatment with NS-398. Whereas SC-560 had no significant effects on the total cellular expression of Kv1.4 channel protein, indomethacin and NS-398 decreased not only the total cellular expression of Kv1.4, but also the cell surface expression of both Kv1.4 and Kv1.6 channel subunits in IEC-Cdx2. Both Kv1.4 and Kv1.6 channel proteins were immunoprecipitated by Kv1.4 antibody from IEC-Cdx2 lysates, indicating that these subunits co-assemble to form heteromeric Kv channels. These results suggest that NSAID inhibition of epithelial cell migration is independent of polyamine-depletion, and is associated with depolarization of Em and decreased surface expression of heteromeric Kv1 channels.ID: S0006295207001931; M3: Article; Accession Number: S0006295207001931; Author: L.C. Freeman (b); Author: D.F. Narvaez (a); Author: A. McCoy (a); Author: F.B. von Stein (c); Author: S. Young (b); Author: K. Silver (a); Author: S. Ganta (b); Author: D. Koch (b); Author: R. Hunter (b); Author: R.F. Gilmour (c); Author: J.D. Lillich (a, ⁎); Affiliation: Department of Clinical Sciences, Kansas State University, Manhattan, KS 66506, United States; Affiliation: Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, United States; Affiliation: Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, United States; Keyword: Non-steroidal anti-inflammatory drugs; Keyword: Intestinal epithelial cells; Keyword: Membrane potential; Keyword: Potassium channels; Number of Pages: 12; Language: English;Source type: Electronic(1)http://search.ebscohost.com/login.aspx?direct=true&db=edselp&AN=S0006295207001931&site=eds-live&scope=sit
Dietary fat oxidation is elevated in middle-aged type 2 diabetes
No full textThis is the author accepted manuscript. The final version is available from the publisher via the link in this record.N/
Does skeletal muscle carnitine availability influence fuel selection during exercise?
No full textFat and carbohydrate are the major fuel sources utilised for oxidative, mitochondrial ATP resynthesis during human skeletal muscle contraction. The relative contribution of these two substrates to ATP resynthesis and total energy expenditure during exercise can vary substantially, and is predominantly determined by fuel availability and exercise intensity and duration. For example, the increased ATP demand that occurs with an increase in exercise intensity is met by increases in both fat and carbohydrate oxidation up to an intensity of approximately 60–70 % of maximal oxygen consumption. When exercise intensity increases beyond this workload, skeletal muscle carbohydrate utilisation is accelerated, which results in a reduction and inhibition of the relative and absolute contribution of fat oxidation to total energy expenditure. However, the precise mechanisms regulating muscle fuel selection and underpinning the decline in fat oxidation remain unclear. This brief review will primarily address the theory that a carbohydrate flux-mediated reduction in the availability of muscle carnitine to the mitochondrial enzyme carnitine palmitoyltransferase 1, a rate-limiting step in mitochondrial fat translocation, is a key mechanism for the decline in fat oxidation during high-intensity exercise. This is discussed in relation to recent work in this area investigating fuel metabolism at various exercise intensities and taking advantage of the discovery that skeletal muscle carnitine content can be nutritionally increased in vivo in human subjects
Branching fraction and CP asymmetry of the decays B+→K0Sπ+ and B+→K0SK+
No full textAn analysis of B+ → K0
Sπ+ and B+ → K0
S K+ decays is performed with the LHCb experiment. The pp
collision data used correspond to integrated luminosities of 1 fb−1 and 2 fb−1 collected at centre-ofmass
energies of
√
s = 7 TeV and
√
s = 8 TeV, respectively. The ratio of branching fractions and the
direct CP asymmetries are measured to be B(B+ → K0
S K+
)/B(B+ → K0
Sπ+
) = 0.064 ± 0.009 (stat.) ±
0.004 (syst.), ACP(B+ → K0
Sπ+
) = −0.022 ± 0.025 (stat.) ± 0.010 (syst.) and ACP(B+ → K0
S K+
) =
−0.21 ± 0.14 (stat.) ± 0.01 (syst.). The data sample taken at
√
s = 7 TeV is used to search for
B+
c
→ K0
S K+ decays and results in the upper limit ( fc · B(B+
c
→ K0
S K+
))/( fu · B(B+ → K0
Sπ+
)) <
5.8 × 10−2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a ¯b
quark
into a B+
c or a B+ meson, respectively
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