Tokamak operation with safety factor q95 < 2 via control of MHD stability.

Magnetic feedback control of the resistive-wall mode has enabled the DIII-D tokamak to access stable operation at safety factor q(95) = 1.9 in divertor plasmas for 150 instability growth times. Magnetohydrodynamic stability sets a hard, disruptive limit on the minimum edge safety factor achievable in a tokamak, or on the maximum plasma current at a given toroidal magnetic field. In tokamaks with a divertor, the limit occurs at q(95) = 2, as confirmed in DIII-D. Since the energy confinement time scales linearly with current, this also bounds the performance of a fusion reactor. DIII-D has overcome this limit, opening a whole new high-current regime not accessible before. This result brings significant possible benefits in terms of fusion performance, but it also extends resistive-wall mode physics and its control to conditions never explored before. In present experiments, the q(95) < 2 operation is eventually halted by voltage limits reached in the feedback power supplies, not by intrinsic physics issues. Improvements to power supplies and to control algorithms have the potential to further extend this regime.

[Vaginal tridimensionel ultrasound interest for the assessment of correct Essure sterilization micro-insert placement]. / Intérêt de l'échographie 3D vaginale pour le contrôle du positionnement des dispositifs Essure.

OBJECTIVES: To determine the interest and simplicity of 3D ultrasound for the 3-month check in place of the recommended routine radiologic in a general gynecology practice. PATIENTS AND METHOD: Twenty-five patients had routine radiologic and transvaginal 3D ultrasound (Voluson 730 Expert) 3 months after placement of Essure micro-insert. RESULTS: Twenty-one 3D acquisitions were realized. In all cases, the micro-insert are easily visualized. Ideally, the echogenic micro-insert appears in the cornuale portion of the fallopian tube. The relationship between the micro insert and the uterine cavity is well documented. CONCLUSION: Easy-to-use, good reproducibility, absence of radiation, make the 3D ultrasound an interesting alternative for the 3-month check. The coronal view gives a directly exploitable document for the surgeon.

Fast-ion losses due to high-frequency MHD perturbations in the ASDEX upgrade Tokamak.

Time-resolved energy and pitch angle measurements of fast-ion losses correlated in frequency and phase with high-frequency magnetohydrodynamic perturbations have been obtained for the first time in a magnetic fusion device and are presented here. A detailed analysis of fast-ion losses due to toroidal Alfvén eigenmodes has revealed the existence of a new core-localized magnetohydrodynamic perturbation, the sierpes mode. The sierpes mode is a non-Alfvénic instability which dominates the losses of fast ions in ion cyclotron resonance heated discharges, and it is named for its footprint in the spectrograms ("sierpes" means "snake" in Spanish). The sierpes mode has been reconstructed by means of highly resolved multichord soft-x-ray measurements.

Active-feedback control of the magnetic boundary for magnetohydrodynamic stabilization of a fusion plasma.

Stable operation with control on magnetohydrodynamic modes has been obtained in the modified reversed field experiment employing a set of 192 feedback controlled saddle coils. Improvements of plasma temperature, confinement (twofold), and pulse length (threefold) and, as a consequence of the magnetic fluctuation reduction, strong mitigation of plasma-wall interaction and mode locking are reported.

Measurements of the MHD dynamo in the quasi-single-helicity reversed-field pinch.

The first experimental study of the MHD dynamo in a quasi-single-helicity (QSH) reversed-field pinch toroidal plasma is presented. In QSH plasmas, a dominant wave number appears in the velocity fluctuation spectrum. This velocity component extends throughout the plasma volume and couples with magnetic fluctuations to produce a significant MHD dynamo electric field. The narrowing of the velocity fluctuation spectrum and the single-mode character of the dynamo are features predicted by theory and computation, but only now are observed in experiment.

Observations of multiple magnetic islands in the core of a reversed field pinch.

We describe in this Letter the first measurement of multiple islands in the core of a reversed field pinch (RFP). These islands appear with current profile modification leading to magnetic fluctuation reduction in the Madison symmetric torus RFP. Magnetic island widths decrease to an unprecedented level, reducing the overlap of adjacent islands and allowing distinct islands to appear. The structures are observed in multichord measurements of soft-x-ray emissivity. The soft-x-ray data is validated with Poincaré reconstructions of the magnetic field structure in the core.

Prognostic value of lymphovascular space invasion determined with hematoxylin-eosin staining in early stage cervical carcinoma: results of a multivariate analysis.

BACKGROUND: Our aim was to study the prognostic value of the presence of lymphovascular space invasion (LVSI) in patients with stage IB and II cervical carcinoma treated by initial surgery. PATIENTS AND METHODS: A retrospective analysis was performed on 193 patients who underwent, between 1985 and 1998, an initial radical hysterectomy with pelvic (+/- para-aortic) lymphadenectomy using midline laparotomy for stage IB (180 patients) or II (13 patients) cervical carcinoma. Postoperative therapy was delivered according to prognostic factors. RESULTS: The rate of LVSI correlated significantly with tumor stage, nodal status and the location of positive nodes. Using univariate analysis, tumor size (<4 or >/= 4 cm), LVS status and nodal status were prognostic factors. At multivariate analysis, two prognostic factors were identified: LVS status and nodal status. In a subgroup of 89 patients with a small tumor (

[Unusual anorectal anomalies. A clinical contribution]. / Anomalie anorettali rare. Contributo clinico.

Anorectal malformations (ARM) include a spectrum of anomalies which have been subdivided as "high", "intermediate" and "low"; a fourth group, defined as "miscellaneous", collects the forms which are most rarely observed. It is important, for a specialist, to know the last ones under the diagnostic and/or therapeutic profile. In this paper, the various problems observed in five cases of ARM considered particularly rare are analysed: a case of anorectal agenesia with recto-cloacal fistula and short uro-genital sinus; a rectal atresia with normal anal canal; a case of anorectal stenosis; an incomplete anal membrane; an anal agenesia with scrotal fistula.

[Vascular traumatic lesions in childhood and adolescence]. / Lesioni traumatiche vascolari in età pediatrica e adolescenziale.

The authors report their experience about 35 peripheric vascular injuries in childhood and adolescence. They analyze the epidemiological and clinical data and underline the usefulness of careful clinical and instrumental diagnosis. In order to obtain the best result they stress the importance of early revascularization by suturing in short lesions and by autologous tissue in longer lesions. Furthermore, they stress the importance of repairing venous injuries. Bone fractures have to be stabilized before vascular repair, subject to this not requiring prolonged ischemia. The authors conclude that only a multidisciplinary approach can ensure better results.

Acetyl-L-carnitine restores choline acetyltransferase activity in the hippocampus of rats with partial unilateral fimbria-fornix transection.

Transection of the fimbria-fornix bundle in adult rats results in degeneration of the septohippocampal cholinergic pathway, reminiscent of that occurring in aging as well as Alzheimer disease. We report here a study of the effect of a treatment with acetyl-L-carnitine (ALCAR) in three-month-old Fischer 344 rats bearing a partial unilateral fimbria-fornix transection. ALCAR is known to ameliorate some morphological and functional disturbances in the aged central nervous system (CNS). We used choline acetyltransferase (ChAT) and acetyl cholinesterase (AChE) as markers of central cholinergic function, and nerve growth factor (NGF) levels as indicative of the trophic regulation of the medio-septal cholinergic system. ChAT and AChE activities were significantly reduced in the hippocampus (HIPP) ipsilateral to the lesion as compared to the contralateral one, while no changes were observed in the septum (SPT), nucleus basalis magnocellularis (NBM) or frontal cortex (FCX). ALCAR treatment restored ChAT activity in the ipsilateral HIPP, while AChE levels were not different from those of untreated animals, and did not affect NGF content in either SPT or HIPP.

Inhaled formoterol in the prevention of exercise-induced bronchoconstriction in asthmatic children.

The duration and magnitude of the effect of inhaled formoterol (12 micrograms) against exercise-induced bronchoconstriction (EIB) was compared with that of inhaled salbutamol (200 micrograms) and that of placebo in 15 children with asthma and EIB in a double-blind, double-dummy, within-patient, placebo-controlled study. The treatments were given by metered dose aerosol on three different days. The exercise test was performed at the 3rd and the 12th hour after dosing. The magnitude of the blocking effect was assessed both by evaluating the lowest FEV1 reading obtained within an hour after each exercise test and by considering the percent decrease below the baseline FEV1 measured before drug administration. Comparison of the lowest values obtained during the hour after each exercise test shows that formoterol was significantly better than both salbutamol (p = 0.022), and placebo (p = 0.001) in limiting exercise-induced bronchoconstriction after the first exercise test (3 h after dosing), while no difference was observed between salbutamol and placebo (p = 0.198). After the second exercise test (12 h after dosing), formoterol again proved to be more effective than both salbutamol (p = 0.008) and placebo (p = 0.001), and no significant difference was observed between salbutamol and placebo (p = 0.391). The evaluation of the mean percentage decrease in FEV1 confirmed the results in favor of formoterol in both the exercise tests. No adverse effects were reported in any treatment group. The protection against EIB is significantly more prolonged after formoterol than after salbutamol, and persists for 12 h after dosing.

Acetyl-L-carnitine treatment increases choline acetyltransferase activity and NGF levels in the CNS of adult rats following total fimbria-fornix transection.

Transection of the fimbria-fornix in adult rats is a useful model for producing impairments of cholinergic activity in the hippocampus (HIPP) and atrophy of the medial septum cholinergic perikarya, similar to those observed during senescence, that are possibly due to the lack of nerve growth factor (NGF) retrogradely transported from the hippocampus. In our investigation we used choline acetyltransferase (ChAT) as an index of cholinergic activity in HIPP, frontal cortex (FCX), septum and nucleus basalis magnocellularis (NBM) along with measurements of NGF levels in the HIPP. Three-month-old rats with unilateral total fimbria transection received acetyl-L-carnitine (ALCAR) (150 mg/kg/day) in drinking water for 1 week before and 4 weeks after the lesion). ALCAR is a substance known to ameliorate some morphological and functional disturbances in the aging central nervous system (CNS). ChAT activity in septum and FCX, and NGF levels in HIPP were significantly increased in the treated group, compared with untreated control groups, while no changes were found in the NBM. On the other hand, a similar ALCAR treatment in unoperated animals induced an increase in ChAT activity in FCX but not in septum nor in NBM. These data are suggestive of a neurotrophic property of ALCAR exerted on those central cholinergic pathways typically damaged by aging.

Counteraction on experimentally induced diabetic neuropathy by levocarnitine acetyl.

The effect of levocarnitine acetyl on diabetic peripheral neuropathy induced by a single injection of streptozotocin or alloxan was studied. Levocarnitine acetyl was administered intraperitoneally one week after induction of diabetes at the dose of 50 mg/kg/day for five and ten weeks. At the end of treatment, neuromuscular conduction velocity (m/sec) was evaluated by stimulating the sciatic nerve and recording the soleus muscle potentials evoked, and the muscle contraction force (mm) by measuring the isometric muscular tension. Motor coordination was evaluated on the Rota-rod apparatus. Treatment with levocarnitine acetyl fully prevented the reduction (20%) in the neuromuscular conduction velocity observed in both experimental models of diabetes. The decrease (30-33%) in muscle contraction force was prevented partially in streptozotocin-induced diabetes and fully in alloxan-induced diabetes. Levocarnitine acetyl also improved the concomitantly reduced motor performance. The results of the present study suggest a beneficial effect of levocarnitine acetyl on peripheral neuropathy and muscle performance.

Severity of early separation and later abusive mothering in monkeys: what is the pathogenic threshold?

This study reports on a nonexperimentally induced case of infant abuse by a macaque mother living in a stable social group. The case is of particular interest because of the early experience of the abusive mother: she had been abandoned right after birth by her biological mother, adopted and reared by an adoptive mother who provided adequate maternal care. The abusive mother alternated violent abuse and attentive maternal care and was shown to have a very possessive relationship with her infant. This study raises questions about etiology of primate infant abuse and supports the view that maternal anxiety may play a role in precipitating abuse.