Precision data are presented for the break-up reaction, 2 H( p, pp)n, within the framework of nuclear-force studies. The experiment was carried out at KVI using a polarized-proton beam of 190 MeV impinging on a liquid-deuterium target and by exploiting the detector, BINA. Some of the vector-analyzing powers are presented and compared with state-of-the-art Faddeev calculations including three-nucleon forces effect. Significant discrepancies between the data and theoretical predictions were observed for kinematical configurations which correspond to the 2 H( p, 2 He)n channel. These results are compared to the 2 H( p, d)p reaction to test the isospin sensitivity of the present three-nucleon force models. The current modeling of two and three-nucleon forces is not sufficient to describe consistently polarization data for both isospin states. Understanding the exact nature of the nuclear force is one of the long-standing questions in nuclear physics. In 1935, Yukawa successfully described the pair-wise nucleon-nucleon (NN) interaction as an exchange of a boson [1]. Current NN models are mainly based on Yukawa's idea and provide an excellent description of the high-quality database of proton-proton and neutron-proton scattering [2] and of the properties of the deuteron. However, for the simplest three-nucleon system, triton, three-body calculations employing NN forces clearly underestimate the experimental binding energies [3], demonstrating that NN forces are not sufficient to describe the three-nucleon system accurately. Some of the discrepancies between experimental data and calculations solely based on the NN interaction can be resolved by introducing an additional three-nucleon force (3NF). Most of the current models for the 3NF are based on a refined version of Fujita-Miyazawa's 3NF model [4], in which a 2π-exchange mechanism is incorporated by an intermediate ∆ excitation of one of the nucleons [5,6].The structure of the 3NF can be studied via a measurement of observables in three-nucleon scattering processes. More detailed information on the spin dependence of the 3NF can be obtained by measuring polarization observables such as the analyzing powers. For this, a series of * Electronic address: messchendorp@kvi.nl extensive studies of 3NF effects in elastic-scattering reactions have been performed at KVI and other laboratories. Precision measurements of the vector analyzing power of the proton in elastic proton-deuteron scattering have been performed at various beam energies ranging from 90 to 250 MeV [7,8,9,10,11]. Also, vector and tensor analyzing powers in elastic deuteron-proton scattering have been obtained at various beam energies ranging from 75 to 270 MeV [12,13,14,15,16,17]. In these measurements, systematic discrepancies between data and theoretical predictions which rigorously solve the Faddeev equations and using only NN potentials were observed. A large part of the discrepancies were removed by adding a 3NF to the NN potentials. Nevertheless, there are still unresolved problems specially at higher...

PURPOSE. The roles of dystrophins in retinal physiology remain elusive. The lack of proper clustering of the potassium channel Kir4.1 and of the aquaporin AQP4 was proposed to be the basis of the ERG abnormality observed in many Duchenne muscular dystrophy (DMD) patients. However, the electroretinogram of Dp71-null mice, in which this clustering is disrupted, shows only a moderate reduction of the b-wave with no change in the implicit times. Additionally, the deficit in color discrimination found in DMD patients is hard to explain through the known expression of DMD gene products. The authors thus decided to reexamine their distribution in the mouse retina. METHODS. Messenger RNA distribution was assessed by PCR coupled to laser microdissection of the outer and inner nuclear layers and by in situ hybridization for Dp427. Mouse retinas were double labeled for dystrophins versus presynaptic and postsynaptic proteins or antibodies specific for Dp427 or Dp427+Dp260. RESULTS. Messengers for Dp427, Dp260, and Dp140 were present in the inner nuclear layer. Dp427 mRNA was further detected in bipolar cells and in some amacrine cells by in situ hybridization. Comparative labeling in wild-type and mdx(5Cv) retinas (lacking Dp427) indicated a differential distribution of Dp427 and Dp260 between rod and cone terminals. CONCLUSIONS. In addition to their localization in photoreceptor terminals, Dp427, Dp260, and Dp140 are expressed in inner nuclear layer neurons, notably in bipolar cells for Dp427. Dp427 was proportionally more expressed in cone- than in rod-associated synapses compared with Dp260.