First Precision Measurement of the Parity Violating Asymmetry in Cold Neutron Capture on

We report the first precision measurement of the parity-violating asymmetry in the direction of proton momentum with respect to the neutron spin, in the reaction ^{3}He(n,p)^{3}H, using the capture of polarized cold neutrons in an unpolarized active ^{3}He target. The asymmetry is a result of the weak interaction between nucleons, which remains one of the least well-understood aspects of electroweak theory. The measurement provides an important benchmark for modern effective field theory and potential model calculations. Measurements like this are necessary to determine the spin-isospin structure of the hadronic weak interaction. Our asymmetry result is A_{PV}=[1.55±0.97(stat)±0.24(sys)]×10^{-8}, which has the smallest uncertainty of any hadronic parity-violating asymmetry measurement so far.

Experimental Evidence of a Variant Neutron Spectrum from the T(t,2n)α Reaction at Center-of-Mass Energies in the Range of 16-50 keV.

Full calculations of six-nucleon reactions with a three-body final state have been elusive and a long-standing issue. We present neutron spectra from the T(t,2n)α (TT) reaction measured in inertial confinement fusion experiments at the OMEGA laser facility at ion temperatures from 4 to 18 keV, corresponding to center-of-mass energies (E_{c.m.}) from 16 to 50 keV. A clear difference in the shape of the TT-neutron spectrum is observed between the two E_{c.m.}, with the ^{5}He ground state resonant peak at 8.6 MeV being significantly stronger at the higher than at the lower energy. The data provide the first conclusive evidence of a variant TT-neutron spectrum in this E_{c.m.} range. In contrast to earlier available data, this indicates a reaction mechanism that must involve resonances and/or higher angular momenta than L=0. This finding provides an important experimental constraint on theoretical efforts that explore this and complementary six-nucleon systems, such as the solar ^{3}He(^{3}He,2p)α reaction.

Effects of dopamine receptor antagonist antipsychotic therapy on blood pressure.

WHAT IS KNOWN AND OBJECTIVE: Hypertension, a major risk factor for adverse cardiovascular events, such as stroke and myocardial infarction, affects 80 million American adults. The aetiology of hypertension is multifaceted and difficult to identify. Dopamine receptors, especially those in the kidneys, play a role in blood pressure regulation, and alterations in their function can cause hypertension. The objective of this review was to investigate the association between the use of dopamine antagonists with hypertension focusing especially on second-generation antipsychotics, like clozapine that is D4 receptor antagonist. METHODS: A literature review was conducted using MEDLINE, Ovid, Science Direct, Web of Science and Cochrane Database of Systematic Reviews databases with keywords:hypertension, hypotension, renin-angiotensin-aldosterone system, dopaminergic receptors, blood pressure, antipsychotics. Inclusion criteria were human or animal studies, systematic reviews, meta-analyses, randomized controlled trials, case report/series, published in selected for inclusion. RESULTS AND DISCUSSION: All 5 dopamine receptor subtypes (ie D1, D2, D3, D4 and D5) regulate sodium excretion and BP. The D1, D3 and D4 receptors interact directly with the renin-angiotensin-aldosterone system, whereas D2 and D5 receptors directly interact with the sympathetic nervous system to regulate BP. Use of dopaminergic agonists or antagonists could therefore disturb the regulation of BP by dopamine receptors. WHAT IS NEW AND CONCLUSION: Based upon this review, individuals on antipsychotic agents, particularly clozapine, should be routinely monitored for hypertension, and addition of antihypertensive agents such as angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) is indicated if hypertension occurs.

Proton Spectra from

Few-body nuclear physics often relies upon phenomenological models, with new efforts at the ab initio theory reported recently; both need high-quality benchmark data, particularly at low center-of-mass energies. We use high-energy-density plasmas to measure the proton spectra from ^{3}He+T and ^{3}He+^{3}He fusion. The data disagree with R-matrix predictions constrained by neutron spectra from T+T fusion. We present a new analysis of the ^{3}He+^{3}He proton spectrum; these benchmarked spectral shapes should be used for interpreting low-resolution data, such as solar fusion cross-section measurements.

A consistent set of neutron kerma coefficients from thermal to 150 MeV for biologically important materials.

Neutron cross sections for nonelastic and elastic reactions on a range of elements have been evaluated for incident energies up to 150 MeV. These cross sections agree well with experimental cross section data for charged-particle production as well as neutron and photon production. Therefore they can be used to determine kerma coefficients for calculations of energy deposition by neutrons in matter. Methods used to evaluate the neutron cross sections above 20 MeV, using nuclear model calculations and experimental data, are described. Below 20 MeV, the evaluated cross sections from the ENDF/B-VI library are adopted. Comparisons are shown between the evaluated charged-particle production cross sections and measured data. Kerma coefficients are derived from the neutron cross sections, for major isotopes of H, C, N, O, Al, Si, P, Ca, Fe, Cu, W, Pb, and for ICRU-muscle, A-150 tissue-equivalent plastic, and other compounds important for treatment planning and dosimetry. Numerous comparisons are made between our kerma coefficients and experimental kerma coefficient data, to validate our results, and agreement is found to be good. An important quantity in neutron dosimetry is the kerma coefficient ratio of ICRU-muscle to A-150 plastic. When this ratio is calculated from our kerma coefficient data, and averaged over the neutron energy spectra for higher-energy clinical therapy beams [three p (68) + Be beams, and a d (48.5) + Be beam], a value of 0.94 +/- 0.03 is obtained. Kerma ratios for water to A-150 plastic, and carbon to oxygen, are also compared with measurements where available.

Quantitation of glomerular angiotensin II receptors in IgA nephropathy.

Mesangial cells have receptors for angiotensin II (AII) and contract in its presence. All is known also to increase the uptake of macromolecules by the mesangium. As a first step towards the investigation of a possible role for local disturbances of the renin-angiotensin system (RAS) in immune mediated mesangial proliferative glomerulonephritis, glomerular All receptors have been quantitated retrospectively in biopsy tissue from 20 patients with IgA nephropathy for comparison with 16 biopsies that showed only minor abnormalities by light microscopy and negative immunofluorescence. An autoradiographic technique using 125I labelled [Sar1, Ile8] All facilitated the quantitation of All receptors in frozen tissue sections. Following exposure to the treated sections, x-ray film was analyzed by computerized micro-densitometry. The data obtained were optical densities of areas corresponding to the presence of glomeruli verified by reference to adjacent sections stained with periodic acid-Schiff (PAS). There was no significant difference between patients 0.67 +/- 0.16 (mean +/- SD) and controls 0.61 +/- 0.15. Among patients there was no statistically significant correlation of glomerular All receptor density with either the degree of mesangial proliferation or the extent of hyperplasia of the juxtaglomerular apparatus (JGA). There was no apparent relationship with hypertension. The absence of an increase in glomerular All receptors despite proliferation of the glomerular mesangium may represent a local down regulation in patients with IgA nephropathy.

Quantum Monte Carlo calculations of neutron-alpha scattering.

We describe a new method to treat low-energy scattering problems in few-nucleon systems, and we apply it to the five-body case of neutron-alpha scattering. The method allows precise calculations of low-lying resonances and their widths. We find that a good three-nucleon interaction is crucial to obtain an accurate description of neutron-alpha scattering.

Optical Constants of Water in the 200-nm to 200-microm Wavelength Region.

Extinction coefficients k(lambda) for water at 25 degrees C were determined through a broad spectral region by manually smoothing a point by point graph of k(lambda) vs wavelength lambda that was plotted for data obtained from a review of the scientific literature on the optical constants of water. Absorption bands representing k(lambda) were postulated where data were not available in the vacuum uv and soft x-ray regions. A subtractive Kramers-Kronig analysis of the combined postulated and smoothed portions of the k(lambda) spectrum provided the index of refraction n(lambda) for the spectral region 200 nm

Kramers-kronig analysis of relative reflectance spectra measured at an oblique angle.

Relative specular reflectance R is defined as R = R(s)/R(w), where R(s) and R(w) are absolute reflectances of a sample material s and a material w for which the index of refraction n(w) and the extinction coefficient k(w) are known quantities. An algorithm was developed for computing n(s)and k(s) from the sample's R spectrum measured for radiant flux polarized perpendicular to the plane of incidence and reflected at oblique angle theta. Kramers-Kronig analysis of the R spectrum provides DeltaPhi the difference between phase shifts for electromagnetic waves reflected at the surfaces of materials s and w. Real and imaginary parts of a Fresnel equation for relative reflectivity provide equations for computing n(s) and k(s) when theta, DeltaPhi n(w), and k(w) are known quantities. Optical constants for aqueous solutions containing NaCl were computed in this manner; distilled water was the reflectance standard.

Evidence for IgA-specific B cell hyperactivity in patients with IgA nephropathy.

Spontaneous in vitro IgA synthesis by peripheral blood mononuclear cells (PBMC) of patients with IgA nephropathy was elevated; 419 +/- 71 ng/10(6) cells (Mean +/- SEM) compared with controls; 217 +/- 35 (P less than 0.02). Pokeweed mitogen (PWM) stimulated IgA synthesis was also elevated in patients; 4326 +/- 1140 ng/10(6) cells (Mean +/- SEM) versus 1458 +/- 406 (P less than 0.02) but the PWM stimulation index for patients did not differ significantly from that of the controls. Concanavalin A (Con A) suppression of PWM stimulated IgA synthesis resulted in the generation of similar quantities of IgA by PBMC from both patients and controls but the percentage suppression was significantly elevated in patients; 87 +/- 5 (Mean +/- SEM) versus 58 +/- 10 (P less than 0.05). Synthesis of IgG and IgM followed the same pattern as that described for IgA. T and B cells from patients and controls were cultured alone and in various co-culture permutations. Enriched B cells of patients demonstrated a selectively increased capacity for IgA production; 266 +/- 106 ng/5 X 10(5) cells (Mean +/- SEM) compared with controls; 42 +/- 9 (P less than 0.01) and this parameter correlated significantly with serum IgA concentrations (R = 0.77, P less than 0.05). Overall analysis of co-culture data showed no significant difference between the influences of autologous, control or patient T cells on immunoglobulin synthesis by normal B cells. Autolymphocytotoxic antibodies were not detected and, compared with controls, patient sera had no differential effect on numbers of IgA producing cells generated in culture.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in anti-DNA antibody affinity during exacerbations of systemic lupus erythematosus.

The level and average functional affinity of anti-DNA antibody were measured retrospectively in successive serum samples from 5 patients with systemic lupus erythematosus. In 2 patients, severe flares of disease activity were associated with an increase in the level and average functional affinity of anti-DNA antibodies. Three patients who did not experience significant flares in disease activity exhibited more constant levels of antibody of lower average functional affinity. The appearance of antibody of high functional affinity during disease exacerbations suggests that such antibodies may be pathogenic.

Therapeutic options in IgA nephropathy.

IgA nephropathy (IgAN) is a common form of glomerulonephritis that leads to end-stage renal disease at variable rates in 20% to 30% of cases. A rational approach to therapy requires an understanding of pathogenetic mechanisms that are largely unknown. Several therapeutic approaches have been used, generally in uncontrolled trials, aimed at lowering levels of circulating immune complexes, affecting cellular immunity, or removing antigens through dietary restriction. Thus far, no clear-cut beneficial effects are evident. Alternative means of changing glomerular hemodynamics through prevention of harmful mediators await exploration.

Bowed fingers. A helpful sign in the early diagnosis of systemic sclerosis.

Thirteen patients who had in common the clinical finding of shortened forearm flexors were investigated. Additional findings were Raynaud's phenomenon, arthralgia, reduced pulmonary CO diffusion capacity, abnormal EMG, and histological evidence of myopathy. Clinical and serological features in 2 patients were consistent with features described in the mixed connective tissue disease syndrome. The remainder were regarded as having a limited connective tissue disease syndrome, in all probability, a minimal expression of systemic sclerosis. We suggest that the finding of bowed fingers is a more reliable clinical sign than the assessment of skin texture in determining the presence of minimal connective tissue disease.

Immunoglobulin classes in skin basement membrane in systemic lupus erythematosus: clinical significance and comparison with classes of serum anti-DNA antibodies.

Biopsies of apparently normal skin were obtained from 30 unselected patients with systemic lupus erythematosus. The immunoglobulin class distribution of the immune deposits at the dermal-epidermal junction was determined in order to assess associated disease patterns and to investigate the possibility that the immunoglobulin classes in the skin were an indication of the classes of serum anti-native DNA antibodies. Biopsy specimens containing IgG deposits were obtained from 10 patients with more active disease and a greater incidence of glomerulonephritis than those patients with only IgM deposits or negative biopsies. However, in this unselected group of patients the immunoglobulin class of the immune deposits did not necessarily indicate the class of serum anti-native DNA antibodies. Therefore biopsy of clinically uninvolved skin will not always identify SLE patients with an immunological restriction to IgM antibody production.

Circulating immune complexes in systemic lupus erythematosus: a reappraisal of the solid phase C1q radioimmunoassay.

Data from a pool of 150 patients with systemic lupus erythematosus (SLE) were used to evaluate the clinical usefulness and specificity of the solid phase C1q radioimmunoassay (SPC1q RIA) for circulating immune complexes (CIC). We found that the assay results correlated with the severity of lupus nephritis but that they did not adequately reflect or predict disease activity so as to directly influence decisions regarding treatment. In addition, the contribution of non-IC reactants to the assay results was found to be of some concern. Finally, we could not demonstrate the presence of anti-DNA antibodies in CIC from patients with SLE.

Nuclear data for radiotherapy: presentation of a new ICRU report and IAEA initiatives.

An ICRU report entitled "Nuclear Data for Neutron and Proton Radiotherapy and for Radiation Protection" is in preparation. The present paper presents an overview of this report, along with examples of some of the results obtained for evaluated nuclear cross sections and kerma coefficients. These cross sections are evaluated using a combination of measured data and the GNASH nuclear model code for elements of importance for biological, dosimetric, beam modification and shielding purposes. In the case of hydrogen both R-matrix and phase-shift scattering theories are used. In the report neutron cross sections and kerma coefficients will be presented up to 150 MeV and proton cross sections up to 250 MeV. An IAEA Consultants' Meeting was also convened to examine the "Status of Nuclear Data needed for Radiation Therapy and Existing Data Development Activities in Member States". Recommendations were made regarding future endeavours.