136 research outputs found

    An Unified Approach To Pseudo Scalar Meson Photoproductions Off Nucleons In The Quark Model

    Full text link
    An unified approach to the pseudo scalar meson (π,η\pi, \eta, and KK) photoproduction off nucleons are presented. It begins with the low energy QCD Lagrangian, and the resonances in the s- and u- channels are treated in the framework of the quark model The duality hypothesis is imposed to limit the number of the t-channel exchanges. The CGLN amplitudes for each reaction are evaluated, which include both proton and neutron targets. The important role by the S-wave resonances in the second resonance region is discussed, it is particularly important for the K,ηK, \eta and η\eta^\prime photoproductions.Comment: 31 pages in Latex fil

    Vaccinia virus binds to the scavenger receptor MARCO on the surface of keratinocytes.

    Get PDF
    Patients with altered skin immunity, such as individuals with atopic dermatitis (AD), can have a life-threatening disruption of the epidermis known as eczema vaccinatum after vaccinia virus (VV) infection of the skin. Here, we sought to better understand the mechanism(s) by which VV associates with keratinocytes. The class A scavenger receptor known as MARCO (macrophage receptor with collagenous structure) is expressed on human and mouse keratinocytes and found to be abundantly expressed in the skin of patients with AD. VV bound directly to MARCO, and overexpression of MARCO increased susceptibility to VV infection. Furthermore, ligands with affinity for MARCO, or excess soluble MARCO, competitively inhibited VV infection. These findings indicate that MARCO promotes VV infection and highlights potential new therapeutic strategies for prevention of VV infection in the skin

    Cereal and nonfat milk support muscle recovery following exercise

    Get PDF
    All authors are with the Exercise Physiology and Metabolism Laboratory Department of Kinesiology and Health Education The University of Texas at Austin Austin, TX, USABackground: This study compared the effects of ingesting cereal and nonfat milk (Cereal) and a carbohydrate-electrolyte sports drink (Drink) immediately following endurance exercise on muscle glycogen synthesis and the phosphorylation state of proteins controlling protein synthesis: Akt, mTOR, rpS6 and eIF4E. -- Methods: Trained cyclists or triathletes (8 male: 28.0 ± 1.6 yrs, 1.8 ± 0.0 m, 75.4 ± 3.2 kg, 61.0 ± 1.6 ml O2•kg-1•min-1; 4 female: 25.3 ± 1.7 yrs, 1.7 ± 0.0 m, 66.9 ± 4.6 kg, 46.4 ± 1.2 mlO2•kg-1•min-1) completed two randomly-ordered trials serving as their own controls. After 2 hours of cycling at 60–65% VO2MAX, a biopsy from the vastus lateralis was obtained (Post0), then subjects consumed either Drink (78.5 g carbohydrate) or Cereal (77 g carbohydrate, 19.5 g protein and 2.7 g fat). Blood was drawn before and at the end of exercise, and at 15, 30 and 60 minutes after treatment. A second biopsy was taken 60 minutes after supplementation (Post60). Differences within and between treatments were tested using repeated measures ANOVA. -- Results: At Post60, blood glucose was similar between treatments (Drink 6.1 ± 0.3, Cereal 5.6 ± 0.2 mmol/L, p < .05), but after Cereal, plasma insulin was significantly higher (Drink 123.1 ± 11.8, Cereal 191.0 ± 12.3 pmol/L, p < .05), and plasma lactate significantly lower (Drink 1.4 ± 0.1, Cereal 1.00 ± 0.1 mmol/L, p < .05). Except for higher phosphorylation of mTOR after Cereal, glycogen and muscle proteins were not statistically different between treatments. Significant Post0 to Post60 changes occurred in glycogen (Drink 52.4 ± 7.0 to 58.6 ± 6.9, Cereal 58.7 ± 9.6 to 66.0 ± 10.0 μmol/g, p < .05) and rpS6 (Drink 17.9 ± 2.5 to 35.2 ± 4.9, Cereal 18.6 ± 2.2 to 35.4 ± 4.4 %Std, p < .05) for each treatment, but only Cereal significantly affected glycogen synthase (Drink 66.6 ± 6.9 to 64.9 ± 6.9, Cereal 61.1 ± 8.0 to 54.2 ± 7.2%Std, p < .05), Akt (Drink 57.9 ± 3.2 to 55.7 ± 3.1, Cereal 53.2 ± 4.1 to 60.5 ± 3.7 %Std, p < .05) and mTOR (Drink 28.7 ± 4.4 to 35.4 ± 4.5, Cereal 23.0 ± 3.1 to 42.2 ± 2.5 %Std, p < .05). eIF4E was unchanged after both treatments. -- Conclusion: These results suggest that Cereal is as good as a commercially-available sports drink in initiating post-exercise muscle recovery.Kinesiology and Health [email protected]

    The Kaon-Photoproduction Of Nucleons In The Quark Model

    Full text link
    In this paper, we develop a general framework to study the meson-photoproductions of nucleons in the chiral quark model. The S and U channel resonance contributions are expressed in terms of the Chew-Goldberger-Low-Nambu (CGLN) amplitudes. The kaon-photoproduction processes, γpK+Λ\gamma p\to K^+ \Lambda, γpK+Σ0\gamma p\to K^+ \Sigma^0, and γpK0Σ+\gamma p\to K^0\Sigma^+, are calculated. The initial results show that the quark model provides a much improved description of the reaction mechanism for the kaon-photoproductions of the nucleon with less parameters than the traditional phenomenological approaches.Comment: 25 pages, 9 postscript figures can be obtained from the author

    Editorial: Microorganisms and their derivatives for cancer therapy

    Get PDF
    [Execerpt] Cancer remains an unsolved and challenging problem. In 1890, Dr. William Bradley Coley attempted to use a mixture of dead microbes to treat cancers (Dobosz and Dzieciatkowski, 2019; Liu et al., 2022), establishing the foundation of bacteria-mediated cancer therapy. Given the recent advances in the study of the human microbiome that revealed its crucial role in tumorigenesis, development, therapy, and prognostic evaluation, additional research efforts on cancer microbial therapies have been conducted (Kurtz et al., 2019; Feng et al., 2022), with new findings supporting the potential role of bacteriolytic therapy in cancer. Our Special Research Topic aimed at exploring the trends and recent advances on the use of microorganisms and their derivatives for cancer therapy, on new anticancer agents, new genetic engineering techniques, and synthetic or new identified bacteria, which could be used for cancer monotherapy or adjuvant therapy, as well as understanding the mechanisms underlying their anticancer effects. [...]We appreciate the editorial staff and the contributors who made the Special Research Topic possible. We acknowledge the support by the National Natural Science Foundation of China (Grant Nos. 81971726, 32101218) and the State Key Laboratory of Oncogenes and Related Genes (No. KF2111).info:eu-repo/semantics/publishedVersio

    The electromagnetic effects in isospin symmetry breakings of q{\bar q} systems

    Full text link
    The isospin symmetry breakings of q{\bar q} are investigated in the QCD sum rule method. The electromagnetic effects are evaluated following the procedure requiring that the electromagnetic effects for charged meson be gauge invariant. We find that the electromagnetic effects are also dominant in the isospin violations of rho meson, which have been shown to be the case in the mass splittings of pions. The numerical results for the difference of pion decay constants and the masses of rho mesons are presented, which are consistent with the data.Comment: To appear in Phys. Rev. D (1997

    Effect of a Low Carbohydrate-Moderate Protein Supplement on Endurance Performance in Female Athletes

    Get PDF
    Previous research has shown that consuming a carbohydrate supplement during prolonged endurance exercise improves performance compared to water or placebo. The addition of protein to traditional carbohydrate supplement has been shown to further improve perfomance beyond that of carbohydrate alone. However, few investigations have explored the effect of adding protein to a supplement containing a low carbohydrate concentration. PURPOSE: To investigate if a low carbohydrate and moderate protein supplement, provided during prolonged variable intensity exercise, would improve time to exhaustion in comparison to a traditional carbohydrate supplement. METHODS: Fourteen (n = 14) trained females cyclists and triathletes (30.4 ±1.6 yrs, 2.90 ± 0.15 L⋅min¬-1) cycled on two different occasions for three hours at intensities varying between 45% - 70% VO2max. After three hours, the intensity was increased (average 72.5 % VO2max) and held until exhaustion. Exhaustion was defined as the point at which subjects could no longer hold cadence above 60RPM. Supplements (275ml) were provided every 20 min during exercise and were composed of a 3% carbohydrate/1.2% protein mix (CHO+PRO) or a 6% carbohydrate-only (CHO). The CHO+PRO treatment contained a mixture of glucose (dextrose), maltodextrin and fructose, and whey protein isolate. The CHO treatment was composed of dextrose. CHO+PRO contained half the carbohydrate content and 30% less calories in comparison to CHO. RESULTS: Time to exhaustion (TTE) was significantly greater with CHO+PRO in comparison to CHO (49.94 ± 7.01 vs 42.36 ± 6.21 min, respectively, p = 0.039). CONCLUSIONS: The above result suggests that addition of a moderate protein to a low carbohydrate supplement enhances performance in endurance trained females above that of carbohydrate alone. Improvement in performance occurred despite a lower carbohydrate and caloric content. It is unknown whether the greater performance seen with CHO+PRO was a result of the added protein, the use of a mixture of carbohydrate sources (glucose, maltodextrin and fructose), or their combination

    Calculation of gπNS11g_{\pi NS_{11}} and gηNS11g_{\eta NS_{11}} Couplings in QCD Sum Rules

    Full text link
    We calculate the coupling constants, gπNS11g_{\pi NS_{11}} and gηNS11,usingQCDsumrulesinthepresenceofanexternalmesonfield.AcovariantderivativeisintroducedwithintheS11interpolatingfieldsothatinthenonrelativisticlimitthefielddominantlyreducestotwoquarksintheswavestateandonequarkinthepwavestate.OurresultforthecouplingsobtainedbyfurthermakinguseofthesoftmesontheoremqualitativelyagreeswithitsphenomenologicalvalueextractedfromtheS11(1535)decaywidth.Thepredictionforthecouplingshoweverdependonthevalueofquarkgluoncondensate,g_{\eta NS_{11}}, using QCD sum rules in the presence of an external meson field. A covariant derivative is introduced within the S_{11} interpolating field so that in the nonrelativistic limit the field dominantly reduces to two quarks in the s-wave state and one quark in the p-wave state. Our result for the couplings obtained by further making use of the soft-meson theorem qualitatively agrees with its phenomenological value extracted from the S_{11}(1535) decay width. The prediction for the couplings however depend on the value of quark-gluon condensate, $, which is also important in the calculation of the S_{11}(1535) mass itself within the sum rule approach.Comment: 8 pages (no figure), revte

    The eta Photoproduction of Nucleons and The structure of the Resonance S11(1535) in The Quark Model

    Full text link
    In this paper, we present our study on the η\eta photoproduction based on the chiral quark model. We find that quark model provides a very good description of the η\eta production with much less parameters, and the threshold region is not a reliable source to determine the ηNN\eta NN coupling constant due to its strong dependence on the properties of the resonance S11(1535)S_{11}(1535). We suggest that the systematic data in Elab=1.21.4E_{lab}=1.2 \sim 1.4 GeV region may help us to determine the ηNN\eta NN coupling constant more precisely. The structure of the resonance S11(1535)S_{11}(1535) is discussed, we find that the recent data from Mainz group bring the helicity amplitude much closer to the quark model prediction. However, more studies need to be done to understand the large ηN\eta N branching ratio of the resonance S11(1535)S_{11}(1535). Our results show that the quark model is a very good approach to study the underlying structure of baryon resonances from the meson photoproduction data.Comment: 21 pages in LaTex file, 6 postscript figures can be obtained from the autho

    Effects of Chocolate Milk Supplementation on Recovery from Cycling Exercise and Subsequent Time Trial Performance

    Get PDF
    PURPOSE: Supplementing with carbohydrate plus protein following strenuous endurance exercise has been found to improve both recovery and subsequent aerobic endurance performance beyond that of a carbohydrate supplement alone. The purpose of the present study was to compare the effects of chocolate milk (CM), an isocaloric carbohydrate only supplement (CHO), and placebo (PLA) on markers of endurance exercise recovery and subsequent time trial performance in trained cyclists. METHODS: Ten trained male and female cyclists (5 males, 5 females) performed 3 trials in which they first cycled for 1.5 h at 70% of VO2max, followed by 10 min of intervals that alternated 45% and 90% VO2max. They then recovered in the laboratory for 4 h, and performed a 40 km time trial (TT). The supplements were provided immediately after the first bout and 2 h into the recovery period. Treatments were administered using a double-blind randomized design. RESULTS: TT time was significantly shorter in CM than CHO and PLA (79.43±2.11 vs. 85.74±3.44 and 86.92±3.28 min, respectively, p=\u3c.05). Significant treatment differences were found for plasma insulin, glucose, free fatty acids (FFA) and glycerol. Plasma insulin levels were significantly lower in CM than CHO at recovery time points R45 (47.30±10.54 vs. 58.71±6.01 &#;U/ml, p\u3c.05), R120 (14.32±1.34 vs. 22.53±3.37 &#;U/ml, p\u3c.05) and REnd (15.57±1.53 vs. 34.35±4.55 &#;U/ml, p\u3c.05). Plasma glucose was significantly lower in CM than CHO at recovery time points R45 (76.61±3.08 vs. 101.65±3.47 mg/dL, p\u3c.05) and R120 (74.72±2.22 vs. 81.46±4.87 mg/dL, p\u3c.05). While FFA and glycerol were both higher in PLA than in CM and CHO overall (p\u3c.05 for both), FFA and glycerol were higher in CM than in CHO (p\u3c.05 for both) during recovery and at TTEnd. Blood lactate was significantly higher at R45 and TTEnd in both CM and CHO than in PLA, but no differences were found between CM and CHO. No significant treatment differences were found for myoglobin, CPK, cortisol, and 5 pro- and anti-inflammatory cytokines (TNF-&#;, IL-6, IL-10, IL-8, and IL-1Ra). CONCLUSIONS: Chocolate milk provided during recovery can improve subsequent time trial performance in trained cyclists more effectively than an isocaloric CHO supplement. This may be due to a faster rate of muscle glycogen resynthesis
    corecore