Development and large volume production of extremely high current density YBa2Cu3O7 superconducting wires for fusion.

The fusion power density produced in a tokamak is proportional to its magnetic field strength to the fourth power. Second-generation high temperature superconductor (2G HTS) wires demonstrate remarkable engineering current density (averaged over the full wire), JE, at very high magnetic fields, driving progress in fusion and other applications. The key challenge for HTS wires has been to offer an acceptable combination of high and consistent superconducting performance in high magnetic fields, high volume supply, and low price. Here we report a very high and reproducible JE in practical HTS wires based on a simple YBa2Cu3O7 (YBCO) superconductor formulation with Y2O3 nanoparticles, which have been delivered in just nine months to a commercial fusion customer in the largest-volume order the HTS industry has seen to date. We demonstrate a novel YBCO superconductor formulation without the c-axis correlated nano-columnar defects that are widely believed to be prerequisite for high in-field performance. The simplicity of this new formulation allows robust and scalable manufacturing, providing, for the first time, large volumes of consistently high performance wire, and the economies of scale necessary to lower HTS wire prices to a level acceptable for fusion and ultimately for the widespread commercial adoption of HTS.

High-field superconductivity in C-doped MgB2 bulk samples prepared by a rapid synthesis route.

The upper critical field sets the thermodynamic limit to superconductivity. A big gap is present between the upper-critical-field values measured in MgB2 polycrystalline bulk superconductors and those of thin films, where values as high as ~ 50 T have been achieved at 4.2 K. Filling this gap would unlock the potential of MgB2 for magnet applications. This work presents the results of an extensive experimental campaign on MgB2 bulk samples, which has been guided by a Design of Experiment. We modeled the dependence of the upper critical field on the main synthesis parameters and established a new record (~ 35 T at 4.2 K) preparing C-doped bulk samples by a non-conventional rapid-synthesis route. This value appears to be an upper boundary for the upper critical field in bulk samples. Structural disorder in films seems to act selectively on one of the two bands where superconductivity in MgB2 takes place: this enhances the upper critical field while reducing the critical temperature only by few Kelvins. On the other hand, the critical temperature in bulk samples decreases monotonically when structural disorder increases, and this imposes a limit to the maximum achievable upper critical field.

Benserazide effects on growth hormone, prolactin, and thyrotropin in normal and acromegalic man.

The effect of benserazide administration on the secretion of GH, PRL, and TSH has been considered as an index of dopamine regulatory actions. Nine acromegalic patients and nine normal subjects were given a single 125 mg oral dose of benserazide, and serum GH, PRL, and TSH were determined by RIA methods every 30 min for 4 h. Benserazide did not alter GH values either in normal subjects or in acromegalic patients. A significant increase of serum PRL was found in both groups, and the increase was similar in normoprolactinemic and in hyperprolactinemic acromegalic patients. A significant increase in TSH levels was found only in acromegalic patients. Thus, a decrease in dopamine outside the blood-brain barrier did not affect GH secretion, whereas PRL secretion was changed in the acromegalic as well as in the control group.

Effectiveness of the selective D4 antagonist sonepiprazole in schizophrenia: a placebo-controlled trial.

BACKGROUND: Selective localization of dopamine D(4) receptors in the prefrontal cortex and preferential affinity of clozapine for the dopamine D(4) receptor over the D(2) receptor led to the hypothesis that the superior efficacy of clozapine may be mediated via blockade of the D(4) receptor. This hypothesis was tested by evaluating sonepiprazole, a selective D(4) dopamine antagonist, in schizophrenia patients. METHODS: We treated 467 hospitalized schizophrenia patients with scores of > or = 60 on the Positive and Negative Syndrome Scale (PANSS) with sonepiprazole, olanzapine, or placebo once daily for 6 weeks. The primary efficacy end point was the mean change from baseline in the PANSS total score at 6 weeks. Secondary efficacy end points were the mean change from baseline in the PANSS factor scores, the Brief Psychiatric Rating Scale score, the Clinical Global Impressions Severity of Illness score, and the Calgary Depression Scale score. RESULTS: No statistically significant differences were observed between placebo and any sonepiprazole dose on the primary or any secondary end point after 6 weeks of treatment. Statistically significant differences, favoring olanzapine over placebo, were observed on all efficacy end points but the Calgary Depression Scale. CONCLUSIONS: Sonepiprazole was ineffective for the treatment of patients with schizophrenia.

Effects of carbamazepine on prolactin secretion in normal subjects and in epileptic subjects.

The effects of carbamazepine (CBZ) on spontaneous secretion of prolactin (PRL) and after stimulation with thyrotropin releasing hormone (TRH) were evaluated. Volunteer subjects after acute CBZ administration, and epileptic subjects with complex partial seizures chronically treated with CBZ, were examined. In an epileptic group, CBZ did not change TRH stimulatory effect on PRL secretion. No appreciable changes of PRL spontaneous secretion were observed, and only a small increase of sleep-entrained values with preservation of the normal secretory circadian rhythm was noted, both in normal subjects and in epileptic subjects. This result could be explained by a serotoninergic activity of PRL changes produced by CBZ in these various conditions agrees with the absence of published reports of CBZ side effects associated with hyperprolactinemia.

A technique for verifying the input response function of neutron time-of-flight scintillation detectors using cosmic rays.

An accurate interpretation of DD or DT fusion neutron time-of-flight (nTOF) signals from current mode detectors employed at the Z-facility at Sandia National Laboratories requires that the instrument response functions (IRF's) be deconvolved from the measured nTOF signals. A calibration facility that produces detectable sub-ns radiation pulses is typically used to measure the IRF of such detectors. This work, however, reports on a simple method that utilizes cosmic radiation to measure the IRF of nTOF detectors, operated in pulse-counting mode. The characterizing metrics reported here are the throughput delay and full-width-at-half-maximum. This simple approach yields consistent IRF results with the same detectors calibrated in 2007 at a LINAC bremsstrahlung accelerator (Idaho State University). In particular, the IRF metrics from these two approaches and their dependence on the photomultipliers bias agree to within a few per cent. This information may thus be used to verify if the IRF for a given nTOF detector employed at Z has changed since its original current-mode calibration and warrants re-measurement.

Predicting the sensitivity of the beryllium/scintillator layer neutron detector using Monte Carlo and experimental response functions.

A methodology for obtaining empirical curves relating absolute measured scintillation light output to beta energy deposited is presented. Output signals were measured from thin plastic scintillator using NIST traceable beta and gamma sources and MCNP5 was used to model the energy deposition from each source. Combining the experimental and calculated results gives the desired empirical relationships. To validate, the sensitivity of a beryllium/scintillator-layer neutron activation detector was predicted and then exposed to a known neutron fluence from a Deuterium-Deuterium fusion plasma (DD). The predicted and the measured sensitivity were in statistical agreement.

Luteinizing hormone pulsatile secretion and pituitary response to gonadotropin releasing hormone and to thyrotropin releasing hormone in male epileptic subjects on chronic phenobarbital treatment.

Endocrine changes have been reported in treated epileptic subjects, who often exhibit sexual dysfunctions, but the endocrine effects of single antiepileptic drugs have not been completely elucidated. In this study we have investigated the influence of phenobarbital (PB) on adenopituitary function and on peripheral sexual steroid pattern in 8 epileptic males. Chronic PB treatment does not modify luteinizing hormone (LH) pulsatile secretion. In the same subjects, LH and follicle stimulating hormone (FSH) response to Gonadotropin Releasing Hormone was blunted with respect to healthy controls both in terms of absolute values and of secretion areas. No difference was found in prolactin (PRL) response to Thyrotropin Releasing Hormone. In the epileptic group a significant increase in the levels of sex hormone binding globulin and a consequent decrease of the percent free testosterone have been observed. PB treatment also significantly lowers 17-beta-estradiol mean levels. These data suggest that PB independently affects both gonadotropin secretion and peripheral steroid pattern.

Prolactin secretion in epileptic subjects treated with phenobarbital: sex differences and circadian periodicity.

Circulating basal prolactin (PRL) levels were evaluated in 126 subjects of both sexes with partial or generalized epilepsy, who were treated with phenobarbital (PB) alone or in combination with either phenytoin or benzodiazepines. A significant increase in PRL levels was observed in male, but not in female, patients compared with a sex- and age-matched healthy volunteer group. Circadian PRL secretion, studied in six male epileptic patients on PB monotherapy and in nine normal subjects, showed comparable 24-h PRL mean values and a preserved PRL surge during the night in both groups; however, a statistically significant additional peak was found in male epileptic subjects during the late afternoon. The cosinor analysis of the data, used to evaluate PRL rhythmicity, showed a disruption of the 24-h periodicity in epileptic subjects, while the 12-h periodicity was maintained. These results indicate that central and/or peripheral mechanisms involved in PRL secretion control are more sensitive to PB alone or in combination with other antiepileptic drugs in male than in female subjects. However, the changes of PRL secretion we found were small and unrelated to the different clinical conditions.

Effects of a single oral dose of phenobarbital on prolactin, growth hormone and luteinizing hormone in normal women.

The effects of a single oral dose of phenobarbital (PB) on the 24 h secretion of prolactin, growth hormone and luteinizing hormone have been evaluated in normal women. An EEG record was taken and barbiturate levels assayed in serum. A statistically significant decrease of growth hormone 24 h mean levels was observed and growth hormone and prolactin values during sleep were diminished. No changes in luteinizing hormone concentrations were observed. After PB the EEG showed no important alterations in sleep pattern, but on the power analysis an increase above 16 Hz absolute power was detected during the waking period.

Changes in the dopaminergic control of prolactin secretion and in ovarian steroids in migraine.

Prolactin (PRL) responses to dopamine (DA) blockers and to direct and indirect DA agonists have been studied in 23 healthy women, 17 women with catamenial migraine and 17 with non-catamenial migraine in both their follicular and luteal phases. PRL responses to the DA blockers were greater in the follicular phase of both migraine groups than in controls. The inhibitory effect of nomifensine on PRL secretion was dampened in the follicular phase of both migraine groups. These findings demonstrate an increased PRL reserve in migraine and suggest the existence of a dopaminergic supersensitivity of the lactotrophic postsynaptic DA receptors. The impaired inhibitory effect of nomifensine on PRL secretion hints at a decrease of the presynaptic DA content in tuberoinfundibular DA neurons. In migrainous women 17-beta-oestradiol levels are higher in both ovarian phases, whereas progesterone concentrations and the progesterone to oestradiol ratio are lower than in healthy subjects in the luteal phase. These data suggest the existence of a change in the oestrogen-dependent modulation of pituitary DA receptors.

TSH circadian secretions in aged men and effect of phosphatidylserine treatment.

In 20 euthyroid aged men (from 65 to 85 years of age) no significant circadian periodicity of thyrotropin (TSH) secretion has been shown by the population mean cosinor method. At the end of a period of 30 days of hospitalization the cosinor evaluation of TSH secretion showed a restored highly significant (p less than 0.001) circadian rhythmicity in phosphatidylserine (PS) (400 mg/daily) treated group (10 aged subjects). By contrast, hospitalization seems to further deteriorate the periodicity of the hormone secretion in 10 placebo-treated subjects.