Two-Nucleon Momentum Distributions Measured in 3He(e,e'pp)n

We have measured the 3He(e,e'pp)n reaction at 2.2 GeV over a wide kinematic range. The kinetic energy distribution for `fast' nucleons (p > 250 MeV/c) peaks where two nucleons each have 20% or less, and the third nucleon has most of the transferred energy. These fast pp and pn pairs are back-to-back with little momentum along the three-momentum transfer, indicating that they are spectators. Experimental and theoretical evidence indicates that we have measured distorted two-nucleon momentum distributions by striking the third nucleon and detecting the spectator correlated pair.Comment: 6 pages, 5 figures, submitted to PR

Exclusive ρ0\rho^0 electroproduction on the proton at CLAS

The $e p\to e^\prime p \rho^0$ reaction has been measured, using the 5.754 GeV electron beam of Jefferson Lab and the CLAS detector. This represents the largest ever set of data for this reaction in the valence region. Integrated and differential cross sections are presented. The $W$, $Q^2$ and $t$ dependences of the cross section are compared to theoretical calculations based on $t$-channel meson-exchange Regge theory on the one hand and on quark handbag diagrams related to Generalized Parton Distributions (GPDs) on the other hand. The Regge approach can describe at the $\approx$ 30% level most of the features of the present data while the two GPD calculations that are presented in this article which succesfully reproduce the high energy data strongly underestimate the present data. The question is then raised whether this discrepancy originates from an incomplete or inexact way of modelling the GPDs or the associated hard scattering amplitude or whether the GPD formalism is simply inapplicable in this region due to higher-twists contributions, incalculable at present.Comment: 29 pages, 29 figure

Single pi+ Electroproduction on the Proton in the First and Second Resonance Regions at 0.25GeV^2 < Q^2 < 0.65GeV^2 Using CLAS

The ep -> e'pi^+n reaction was studied in the first and second nucleon resonance regions in the 0.25 GeV^2 < Q^2 < 0.65 GeV^2 range using the CLAS detector at Thomas Jefferson National Accelerator Facility. For the first time the absolute cross sections were measured covering nearly the full angular range in the hadronic center-of-mass frame. The structure functions sigma_TL, sigma_TT and the linear combination sigma_T+epsilon*sigma_L were extracted by fitting the phi-dependence of the measured cross sections, and were compared to the MAID and Sato-Lee models.Comment: Accepted for publication in PR

Measurement of Beam-Spin Asymmetries for Deep Inelastic π+\pi^+ Electroproduction

We report the first evidence for a non-zero beam-spin azimuthal asymmetry in the electroproduction of positive pions in the deep-inelastic region. Data have been obtained using a polarized electron beam of 4.3 GeV with the CLAS detector at the Thomas Jefferson National Accelerator Facility (JLab). The amplitude of the $\sin\phi$ modulation increases with the momentum of the pion relative to the virtual photon, $z$, with an average amplitude of $0.038 \pm 0.005 \pm 0.003$ for $0.5 < z < 0.8$ range.Comment: 5 pages, RevTEX4, 3 figures, 2 table

Observation of Nuclear Scaling in the A(e,e′)A(e,e^{\prime}) Reaction at xB>x_B>1

The ratios of inclusive electron scattering cross sections of $^4$He, $^{12}$C, and $^{56}$Fe to $^3$He have been measured for the first time. It is shown that these ratios are independent of $x_B$ at Q$^2>$1.4 (GeV/c)$^2$ for $x_B>$ 1.5 where the inclusive cross section depends primarily on the high-momentum components of the nuclear wave function. The observed scaling shows that the momentum distributions at high-momenta have the same shape for all nuclei and differ only by a scale factor. The observed onset of the scaling at Q$^2>$1.4 and $x_B >$1.5 is consistent with the kinematical expectation that two nucleon short range correlations (SRC) are dominate the nuclear wave function at $p_m\gtrsim$ 300 MeV/c. The values of these ratios in the scaling region can be related to the relative probabilities of SRC in nuclei with A$\ge$3. Our data demonstrate that for nuclei with A$\geq$12 these probabilities are 5-5.5 times larger than in deuterium, while for $^4$He it is larger by a factor of about 3.5.Comment: 11 pages, 10 figure

The Ergogenic Potential of Arginine

Arginine is a conditionally essential amino acid that is involved in protein synthesis, the detoxification of ammonia, and its conversion to glucose as well as being catabolized to produce energy. In addition to these physiological functions, arginine has been purported to have ergogenic potential. Athletes have taken arginine for three main reasons: 1) its role in the secretion of endogenous growth hormone; 2) its involvement in the synthesis of creatine; 3) its role in augmenting nitric oxide. These aspects of arginine supplementation will be discussed as well as a review of clinical investigations involving exercise performance and arginine ingestion

The YARHG Domain: An Extracellular Domain in Search of a Function

We have identified a new bacterial protein domain that we hypothesise binds to peptidoglycan. This domain is called the YARHG domain after the most highly conserved sequence-segment. The domain is found in the extracellular space and is likely to be composed of four alpha-helices. The domain is found associated with protein kinase domains, suggesting it is associated with signalling in some bacteria. The domain is also found associated with three different families of peptidases. The large number of different domains that are found associated with YARHG suggests that it is a useful functional module that nature has recombined multiple times

Curcumin supplementation could improve diabetes-induced endothelial dysfunction associated with decreased vascular superoxide production and PKC inhibition

<p>Abstract</p> <p>Background</p> <p>Curcumin, an Asian spice and food-coloring agent, is known for its anti-oxidant properties. We propose that curcumin can improve diabetes-induced endothelial dysfunction through superoxide reduction.</p> <p>Methods</p> <p>Diabetes (DM) was induced in rats by streptozotocin (STZ). Daily curcumin oral feeding was started six weeks after the STZ injection. Twelve weeks after STZ injection, mesenteric arteriolar responses were recorded in real time using intravital fluorescence videomicroscopy. Superoxide and vascular protein kinase C (PKC-βII) were examined by hydroethidine and immunofluorescence, respectively.</p> <p>Results</p> <p>The dilatory response to acetylcholine (ACh) significantly decreased in DM arterioles as compared to control arterioles. There was no difference among groups when sodium nitroprusside (SNP) was used. ACh responses were significantly improved by both low and high doses (30 and 300 mg/kg, respectively) of curcumin supplementation. An oxygen radical-sensitive fluorescent probe, hydroethidine, was used to detect intracellular superoxide anion (O₂^●-) production. O₂^●-production was markedly increased in DM arterioles, but it was significantly reduced by supplementation of either low or high doses of curcumin. In addition, with a high dose of curcumin, diabetes-induced vascular PKC-βII expression was diminished.</p> <p>Conclusion</p> <p>Therefore, it is suggested that curcumin supplementation could improve diabetes-induced endothelial dysfunction significantly in relation to its potential to decrease superoxide production and PKC inhibition.</p

Self-Reported Physical Activity: Its Correlates and Relationship with Health-Related Quality of Life in a Large Cohort of Colorectal Cancer Survivors

Background: Physical activity (PA) is suggested to be an important non-pharmacologic means to improve health-related outcomes among cancer survivors. We aimed to describe the PA level, its correlates, and association with health-related quality of life (HRQoL) in colorectal cancer (CRC) survivors. Methods: CRC survivors identified from the Eindhoven Cancer Registry treated between 1998 and 2007 were included. Survivors completed validated questionnaires on PA, distress, fatigue, and HRQoL. Moderate-to-vigorous physical activity (MVPA) levels were calculated by summing the time spent on walking, bicycling, gardening and sports ($3 MET). Multiple linear regression analyses were conducted to study which socio-demographic and clinical factors were associated with MVPA. Furthermore, we examined associations between MVPA and physical and mental HRQoL, and whether these associations were mediated by fatigue and distress. Results: Cross-sectional data of 1371 survivors (response: 82%) were analysed. Participants were 69.5 (SD 9.7) years old, 56% were male, and survival duration was 3.9 (SD 2.5) years. Participants self-reported on average 95.5 (SD 80.3) min on MVPA per day. Younger age, male sex, being employed, non-smoking, lower BMI, colon cancer (vs. rectal cancer), chemotherapy treatment and having no co-morbidities were associated with higher MVPA (p,0.05). MVPA was positively associated with physical HRQoL (regression coefficient of total association (c) = 0.030; se = 0.004) after adjusting for socio-demographic an

Heterologous Protein Expression Is Enhanced by Harmonizing the Codon Usage Frequencies of the Target Gene with those of the Expression Host

Synonymous codon replacement can change protein structure and function, indicating that protein structure depends on DNA sequence. During heterologous protein expression, low expression or formation of insoluble aggregates may be attributable to differences in synonymous codon usage between expression and natural hosts. This discordance may be particularly important during translation of the domain boundaries (link/end segments) that separate elements of higher ordered structure. Within such regions, ribosomal progression slows as the ribosome encounters clusters of infrequently used codons that preferentially encode a subset of amino acids. To replicate the modulation of such localized translation rates during heterologous expression, we used known relationships between codon usage frequencies and secondary protein structure to develop an algorithm (“codon harmonization”) for identifying regions of slowly translated mRNA that are putatively associated with link/end segments. It then recommends synonymous replacement codons having usage frequencies in the heterologous expression host that are less than or equal to the usage frequencies of native codons in the native expression host. For protein regions other than these putative link/end segments, it recommends synonymous substitutions with codons having usage frequencies matched as nearly as possible to the native expression system. Previous application of this algorithm facilitated E. coli expression, manufacture and testing of two Plasmodium falciparum vaccine candidates. Here we describe the algorithm in detail and apply it to E. coli expression of three additional P. falciparum proteins. Expression of the “recoded” genes exceeded that of the native genes by 4- to 1,000-fold, representing levels suitable for vaccine manufacture. The proteins were soluble and reacted with a variety of functional conformation-specific mAbs suggesting that they were folded properly and had assumed native conformation. Codon harmonization may further provide a general strategy for improving the expression of soluble functional proteins during heterologous expression in hosts other than E. coli