Determining the gluonic gravitational form factors of the proton.

The proton is one of the main building blocks of all visible matter in the Universe1. Among its intrinsic properties are its electric charge, mass and spin2. These properties emerge from the complex dynamics of its fundamental constituents-quarks and gluons-described by the theory of quantum chromodynamics3-5. The electric charge and spin of protons, which are shared among the quarks, have been investigated previously using electron scattering2. An example is the highly precise measurement of the electric charge radius of the proton6. By contrast, little is known about the inner mass density of the proton, which is dominated by the energy carried by gluons. Gluons are hard to access using electron scattering because they do not carry an electromagnetic charge. Here we investigated the gravitational density of gluons using a small colour dipole, through the threshold photoproduction of the J/ψ particle. We determined the gluonic gravitational form factors of the proton7,8 from our measurement. We used a variety of models9-11 and determined, in all cases, a mass radius that is notably smaller than the electric charge radius. In some, but not all cases, depending on the model, the determined radius agrees well with first-principle predictions from lattice quantum chromodynamics12. This work paves the way for a deeper understanding of the salient role of gluons in providing gravitational mass to visible matter.

Determination of the

We report the first measurement of the parity-violating elastic electron scattering asymmetry on ^{27}Al. The ^{27}Al elastic asymmetry is A_{PV}=2.16±0.11(stat)±0.16(syst) ppm, and was measured at ⟨Q^{2}⟩=0.02357±0.00010 GeV^{2}, ⟨θ_{lab}⟩=7.61°±0.02°, and ⟨E_{lab}⟩=1.157 GeV with the Q_{weak} apparatus at Jefferson Lab. Predictions using a simple Born approximation as well as more sophisticated distorted-wave calculations are in good agreement with this result. From this asymmetry the ^{27}Al neutron radius R_{n}=2.89±0.12 fm was determined using a many-models correlation technique. The corresponding neutron skin thickness R_{n}-R_{p}=-0.04±0.12 fm is small, as expected for a light nucleus with a neutron excess of only 1. This result thus serves as a successful benchmark for electroweak determinations of neutron radii on heavier nuclei. A tree-level approach was used to extract the ^{27}Al weak radius R_{w}=3.00±0.15 fm, and the weak skin thickness R_{wk}-R_{ch}=-0.04±0.15 fm. The weak form factor at this Q^{2} is F_{wk}=0.39±0.04.

JLab Measurements of the

The charge and magnetic form factors, F_{C} and F_{M}, respectively, of ^{3}He are extracted in the kinematic range 25 fm^{-2}≤Q^{2}≤61 fm^{-2} from elastic electron scattering by detecting ^{3}He recoil nuclei and scattered electrons in coincidence with the two High Resolution Spectrometers of the Hall A Facility at Jefferson Lab. The measurements find evidence for the existence of a second diffraction minimum for the magnetic form factor at Q^{2}=49.3 fm^{-2} and for the charge form factor at Q^{2}=62.0 fm^{-2}. Both minima are predicted to exist in the Q^{2} range accessible by this Jefferson Lab experiment. The data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the three-body nuclear problem.

Publisher's Note: JLab Measurements of the

This corrects the article DOI: 10.1103/PhysRevLett.119.162501.

Production of Highly Polarized Positrons Using Polarized Electrons at MeV Energies.

The Polarized Electrons for Polarized Positrons experiment at the injector of the Continuous Electron Beam Accelerator Facility has demonstrated for the first time the efficient transfer of polarization from electrons to positrons produced by the polarized bremsstrahlung radiation induced by a polarized electron beam in a high-Z target. Positron polarization up to 82% have been measured for an initial electron beam momentum of 8.19 MeV/c, limited only by the electron beam polarization. This technique extends polarized positron capabilities from GeV to MeV electron beams, and opens access to polarized positron beam physics to a wide community.

JLab measurement of the 4He charge form factor at large momentum transfers.

The charge form factor of 4He has been extracted in the range 29 fm(-2) ≤ Q2 ≤ 77 fm(-2) from elastic electron scattering, detecting 4He recoil nuclei and electrons in coincidence with the high resolution spectrometers of the Hall A Facility of Jefferson Lab. The measurements have uncovered a second diffraction minimum for the form factor, which was predicted in the Q2 range of this experiment. The data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the few-body problem.

Graphlet-based edge clustering reveals pathogen-interacting proteins.

MOTIVATION: Prediction of protein function from protein interaction networks has received attention in the post-genomic era. A popular strategy has been to cluster the network into functionally coherent groups of proteins and assign the entire cluster with a function based on functions of its annotated members. Traditionally, network research has focused on clustering of nodes. However, clustering of edges may be preferred: nodes belong to multiple functional groups, but clustering of nodes typically cannot capture the group overlap, while clustering of edges can. Clustering of adjacent edges that share many neighbors was proposed recently, outperforming different node clustering methods. However, since some biological processes can have characteristic 'signatures' throughout the network, not just locally, it may be of interest to consider edges that are not necessarily adjacent. RESULTS: We design a sensitive measure of the 'topological similarity' of edges that can deal with edges that are not necessarily adjacent. We cluster edges that are similar according to our measure in different baker's yeast protein interaction networks, outperforming existing node and edge clustering approaches. We apply our approach to the human network to predict new pathogen-interacting proteins. This is important, since these proteins represent drug target candidates. AVAILABILITY: Software executables are freely available upon request. CONTACT: tmilenko@nd.edu SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Precise extraction of the induced polarization in the 4He(e,e'p)3H reaction.

We measured with unprecedented precision the induced polarization P(y) in (4)He(e,e'p)(3)H at Q(2)=0.8 and 1.3 (GeV/c)(2). The induced polarization is indicative of reaction-mechanism effects beyond the impulse approximation. Our results are in agreement with a relativistic distorted-wave impulse approximation calculation but are overestimated by a calculation with strong charge-exchange effects. Our data are used to constrain the strength of the spin-independent charge-exchange term in the latter calculation.

Probing the high momentum component of the deuteron at high Q2.

The (2)H(e,e'p)n cross section at a momentum transfer of 3.5 (GeV/c)(2) was measured over a kinematical range that made it possible to study this reaction for a set of fixed missing momenta as a function of the neutron recoil angle θ(nq) and to extract missing momentum distributions for fixed values of θ(nq) up to 0.55 GeV/c. In the region of 35°≤θ(nq)≤45° recent calculations, which predict that final-state interactions are small, agree reasonably well with the experimental data. Therefore, these experimental reduced cross sections provide direct access to the high momentum component of the deuteron momentum distribution in exclusive deuteron electrodisintegration.

Search for a new gauge boson in electron-nucleus fixed-target scattering by the APEX experiment.

We present a search at the Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling α' to electrons. Such a particle A' can be produced in electron-nucleus fixed-target scattering and then decay to an e + e- pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175-250 MeV, found no evidence for an A'→ e+ e- reaction, and set an upper limit of α'/α ~/= 10(-6). Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces.

Polarization transfer in the 4He(e,e'p)3H reaction at Q2=0.8 and 1.3 (GeV/c)2.

Proton recoil polarization was measured in the quasielastic 4He(e,e'p)3H reaction at Q{2}=0.8 and 1.3 (GeV/c){2} with unprecedented precision. The polarization-transfer coefficients are found to differ from those of the 1H(e,e'p) reaction, contradicting a relativistic distorted-wave approximation and favoring either the inclusion of medium-modified proton form factors predicted by the quark-meson coupling model or a spin-dependent charge-exchange final-state interaction. For the first time, the polarization-transfer ratio is studied as a function of the virtuality of the proton.

Islets of Langerhans: dye coupling among immunocytochemically distinct cell types.

Cells in isolated rat islets of Langerhans were microinjected with Lucifer Yellow CH in a medium containing 16.7 millimolar glucose. Dye was rapidly transferred from the injected cell to neighboring islet cells without specificity with regard to the immunocytochemical identity of either the donor or the recipient cells. The transfer of dye between the islet cells (types A, B, and D) demonstrates homologous and heterologous cell coupling in a system where the normal proportions and relationships of the cell types are maintained.

Evaluation of transcendental meditation as a method of reducing stress.

Transcendental meditation is said to induce in its practitioners an altered state of consciousness resulting in relief of stress, an increased sense of awareness, and a sense of well-being. Release of catecholamines has been associated widely with stress and lends itself to quantitation. Plasma epinephrine and norephinephrine, as well as lactate, were measured in 12 volunteers before, during, and after meditation. Values were compared with those obtained from controls matched for sex and age who rested instead of meditating. Essentially the same results were obtained for the two groups, which suggests that meditation does not induce a unique metabolic state but is seen biochemically as a resting state.

Prolactin enhances cell-to-cell communication among beta-cells in pancreatic islets.

To determine the role of prolactin in increasing junctional communication among islet beta-cells, we studied dye coupling in pancreatic islets exposed to elevated levels of prolactin in vivo and in vitro. Islets were isolated from rats immediately after lactation or from rats bearing mammosomatotropic tumors (MtTW15), conditions involving high levels of prolactin (either 5-fold or 1000-fold control levels, respectively). When beta-cells were microinjected with the gap junction permeant dye Lucifer yellow CH, the mean number of dye-coupled cells per injection was approximately 10-fold greater than in islets from virgin control rats. As a more direct test of the effects of prolactin on beta-cell coupling, islets isolated from virgin rats were treated for 90 min with 500 ng/ml rat prolactin in the presence of low glucose (2.8 mM) and were microinjected with dye. The mean number of dye-coupled cells per injection increased by 6.7-fold over controls with low glucose, demonstrating a direct effect of prolactin on beta-cell coupling. In vitro treatment with high glucose (16.7 mM) resulted in a 2.7-fold increase in dye-coupled cells per injection. We discuss the possible relationship between the effects of glucose and of prolactin on coupling.

In vivo modulation of gap junctions and dye coupling between B-cells of the intact pancreatic islet.

The extent of gap junctions and dye coupling between insulin-producing B-cells was analyzed on islets of Langerhans isolated from adult rats treated for one day with glibenclamide, an insulin secretagogue, or diazoxide, a blocker of insulin release, or a combination of the two drugs. Glibenclamide treatment was associated with a marked depletion of the islet insulin content, an effect which was blocked by pretreatment of the rats with diazoxide. Diazoxide alone caused a marked increase in the plasma glucose level, and a decrease in the level of circulating insulin and in the hormone content of the B-cells. Quantitative analysis showed that (1) under control conditions, B-cells are connected by minute gap junctions (as evaluated on freeze-fracture replicas) and show a nonuniform and apparently restricted dye coupling (as determined by microinjection of the low-molecular-weight fluorescent probe Lucifer Yellow CH); (2) each of the three treatments tested significantly increased the relative and absolute gap junction area of the B-cells and the number of detectable, dye coupled B-cells per microinjection. After treatment with glibenclamide alone or with diazoxide plus glibenclamide, a 1.5-1.8-fold increase in gap junction area and a 2.7-3.7-fold increase in the number of dye-coupled B-cells were observed. In contrast, following treatment with diazoxide alone, gap junctions and dye coupling were found increased 1.8 and 8.7 times, respectively, as compared with control values.

Empty sella resulting from the spontaneous resolution of a pituitary macroadenoma.

Recent studies suggest that the infarction of a pituitary adenoma may be a frequent cause of an empty sella turcica. However, to date, evidence of such progression has been largely speculative. We present the case of a patient with a pituitary macroadenoma that underwent spontaneous involution resulting in an empty sella, as documented by serial magnetic resonance imaging scans. A brief review of the proposed causes of primary empty sella, with emphasis on pituitary necrosis, is provided.

Once-daily fosinopril in the treatment of hypertension.

This multicenter, dose-ranging study evaluated the antihypertensive effectiveness of once-daily administration of fosinopril sodium in 220 patients with supine diastolic blood pressure of 95-115 mm Hg. After a 4-week placebo period, patients were randomly assigned to double-blind therapy with either placebo or 10, 40, or 80 mg fosinopril once daily for 4 weeks. If treatment goals were not met, chlorthalidone 25 mg/day was added for weeks 5 to 8. Thereafter, patients could enter the long-term, open-label phase and receive 10-80 mg/day fosinopril plus chlorthalidone, if needed. After 4 weeks of monotherapy, the average decreases in supine diastolic blood pressure were 9% (10 mg), 11.5% (40 mg), and 12.5% (80 mg) compared with 6% in the placebo group. After 8 weeks, the average decreases, with or without diuretic therapy, were 12.5-18.2%, compared with 10.8% with placebo. Blood pressure continued to be well controlled, and the patients showed no evidence of tachyphylaxis or tolerance through 12-15 months of treatment. Fosinopril was well tolerated. During the short-term phase, no patient withdrew because of adverse events possibly related to fosinopril; during the long-term phase, nine of 148 patients (6.1%) withdrew for that reason. In patients with mild-to-moderate hypertension, once-daily fosinopril (40 and 80 mg) provided significant antihypertensive effects with or without diuretic therapy. The 10 mg dose was effective in some patients and may be considered a starting dose.

2-[(Phenylthio)methyl]pyridine derivatives: new antiinflammatory agents.

2-[(Phenylthio)methyl]pyridine derivatives inhibited the dermal reverse passive Arthus reaction (RPAR) in the rat. In the same model, indomethacin was inactive, and hydrocortisone was active. Compounds Ia-d also significantly reduced exudate volume and white blood cell accumulation in the pleural RPAR. This pattern of activity was similar to that of hydrocortisone and different from that of indomethacin.

Immunocytochemical identification of dye-injected cells.

Lucifer Yellow CH may be injected into pancreatic islet cells and visualized in Epon sections of the embedded tissue both before and after plastic removal and immunocyto-chemical staining. The dye retains its fluorescence, clearly marking the injected cell and adjacent dye-coupled cells, but does not interfere with the indirect immunofluorescent staining patterns that are characteristic of the islet cells

Human rights consultation: a 12-year experience of a pediatric bioethics committee.

For many years there has been a committee at the Children's Hospital of Pittsburgh to review research proposals to assure that the rights of children are protected. In 1974, its composition was changed and its mission broadened to include consultation and discussion of ethical issues in clinical care. The committee is called the Human Rights Committee to reflect this mission. Medical ethical consultations are performed by rotating on-call teams consisting of a physician and a nonphysician who are members of the committee. Selected cases from 48 consultations are presented to demonstrate the process and to illustrate some of the questions that were addressed. The clinical diagnoses were varied, but the commonest were congenital malformations. The most frequent reason for consultation was to question the advisability of assisted ventilation (27 cases), but other reasons concerned definitive surgery, intravenous hyperalimentation, cardiopulmonary resuscitation, and tracheostomy. Consultations are always optional and advisory. The recommendations of the consultation team are subsequently reviewed by the entire Human Rights Committee. The service has been well received by the medical staff. This method has some of the advantages of both the hospital ethics committee and the single consultant. Therefore, it should be considered when planning how to deal with these important problems.