Conceptual design of a heavy ion beam probe diagnostic for the Wendelstein 7-X Stellarator

This article describes the current state of the design of the heavy ion beam probe (HIBP) for Wendelstein 7-X (W7-X). It will be the first HIBP diagnostic on an optimized stellarator and is designed to study electric fields and ion scale turbulence in all W7-X reference magnetic configurations. The use of an existing 2 MV accelerator, located outside of the torus hall, results in the need for a circuitous primary beamline. This increases the complexity of the ion optics design to deliver a focused beam to the plasma. To access most of the magnetic configuration space of W7-X, the secondary beamline and an energy analyzer are designed to pivot, thereby redirecting a wider range of secondary beam trajectories. Signal level estimates indicate that the equilibrium potential can be measured at all radii and that the radial coverage for potential and density fluctuations measurements depends on the plasma density.

First Observation of a Stable Highly Dissipative Divertor Plasma Regime on the Wendelstein 7-X Stellarator

For the first time, the optimized stellarator Wendelstein 7-X has operated with an island divertor. An operation regime in hydrogen was found in which the total plasma radiation approached the absorbed heating power without noticeable loss of stored energy. The divertor thermography recorded simultaneously a strong reduction of the heat load on all divertor targets, indicating almost complete power detachment. This operation regime was stably sustained over several energy confinement times until the preprogrammed end of the discharge. The plasma radiation is mainly due to oxygen and is located at the plasma edge. This plasma scenario is reproducible and robust at various heating powers, plasma densities, and gas fueling locations. These experimental results show that the island divertor concept actually works and displays good power dissipation potential, producing a promising exhaust concept for the stellarator reactor line.

Tracer-Encapsulated Solid Pellet (TESPEL) injection system for Wendelstein 7-X

Impurity confinement in fusion plasmas is mainly determined by transport mechanisms in the core region. For the Wendelstein 7-X stellarator, its island divertor is expected to screen effectively external impurity sources in the scrape-off layer at higher densities. However, the unique feature of Tracer-Encapsulated Solid Pellet (TESPEL) injection, releasing impurities at a well-localized radial position directly in the core plasma, enables investigating such transport mechanisms. This paper reports on the detailed design of a completely new TESPEL injection system, which has been designed by the National Institute for Fusion Science, Toki, Japan, and is currently being installed at Max-Planck-Institut für Plasmaphysik, Greifswald, Germany, for the Wendelstein 7-X. This injector consists of a storage and injection unit, attached to a system of guiding tubes which run through 3 successive differential pumping stages. A light-gate system and an optical observation system are used to determine the location of the deposited tracers. Laboratory tests carried out by shooting TESPELs onto a sample foil showed good performance after careful realignment of the guiding tubes.

Cognitive-behavioural assessment and treatment of maladaptive help-seeking behaviour in a patient with schizophrenia

OBJECTIVE

Maladaptive help-seeking behaviour in psychiatric patients is a significant problem for public mental health services, yet it is not addressed in the mainstream literature. We present a report on the successful treatment of a person with schizophrenia who displayed this common dilemma for patients and clinicians.

CLINICAL PICTURE

A 31-year-old man with borderline intellectual functioning had a 10-year history of schizophrenia marked by negative features. He frequently presented in crisis to public mental health services, the local hospital, and his general practitioner; this resulted in excessive use of services, including admissions.

TREATMENT

The patient was reassessed from a cognitive-behavioural perspective rather than a syndromal perspective. Specific behaviours were modified, cognitions were identified, challenged and restructured, and other service providers were provided with an alternative to admission or acute community care.

OUTCOME

At 24 months the maladaptive behaviour remains in remission.

CONCLUSIONS

Behavioural problems in persons with chronic schizophrenia may be effectively treated by reconceptualising the behaviour as distinct from the major diagnosis.

Alteration of pancreatic B-cells in Wistar rats treated with non-diabetogenic doses of cyclosporin A

We have investigated the effect of non-immunosuppressive cyclosporin A (CS-A) doses on glucose tolerance, pancreatic insulin content, insulin content of isolated islets and insulin secretion in vitro in response to glucose. Within 12 weeks animals treated permanently with a dose of 2.5 mg CS-A/kg b.wt. developed glucose intolerance (but not hyperglycaemia) accompanied by a decrease of pancreatic insulin content due to a decrease of islet insulin content, whereas the relative B-cell volume density was not changed. Isolated islets obtained from rats treated for 4 weeks had a diminished sensitivity for glucose, whereas islets obtained from animals treated for greater than 4 weeks showed a diminished half-maximum and maximum secretion rate. Rats treated for 12 weeks with 1.25 mg CS-A/kg b.wt. developed an impaired glucose tolerance after 8 weeks accompanied by a diminished pancreatic insulin content. Despite continued treatment the pancreatic insulin content was able to increase and the glucose tolerance to normalize, indicating an adaptation of pancreatic B-cells to CS-A. The results support the theory that a potential toxic effect of cyclosporin A can be diagnosed by functional tests (e.g. insulin secretion in response to a stepwise increase of glucose) before the irreversible (e.g. morphological) alterations occur.

Is the cyclosporin A toxicity on rat pancreatic B-cells modulated by the MHC?

High Cyclosporin A doses (50 mg/kg b.w.) were given male Wistar rats either homozygous for RT1a or RT1u. Both rat strains are characterized by a similar diminished body weight gain. Cyclosporin A exerted in both strains an increased fed plasma glucose, decreased glucose tolerance and diminished pancreatic insulin content, however, the Wistar rat strain with the MHC RT1u was more sensitive to the effect of Cyclosporin A, indicated by a more marked alteration of pancreatic B-cells and a delayed recovery after drug withdrawal. We concluded that the MHC modulated either the Cyclosporin A metabolism (degradation) or the pancreatic B-cell sensitivity to toxic damage.

[Obstetrical neuroleptanalgesia as a procedure for pain control in the peripartal period of the problem patient]

Report on 35 patients treated by obstetric neuroleptanalgesia in the course of labour. This method doesn't appear to be qualified for general application. Nevertheless this kind of analgesia offers an additional possibility to influence the progress of labour favourably.

[Diaplacental influence on the disseminated intravascular coagulation (DIC) in an asphyxia model. I. Influence on the vasal tonus and on the vasal wall (author's transl)]

With the aid of an asphyxia model in rabbit fetuses the possibility of diaplacental influence on the hypoxic effects of the fetal organism has been investigated. The trial to change the vasotonia during the asphyctic shock by sympathicomimetic or -lytic drugs (Dilatol, Obsidan, Ergocomb, Regitin) remained to be without any effect on the DIC in the fetal organism. Trying to seal the vascular wall by the high-molecular-weight basic polypeptide Aprotinin there seemed rather to be an increase of the intravascular fibrin sedimentation.

[Diaplacental influence on the disseminated intravascular coagulation (DIC) in an asphyxia model. II. Influence on the vessel's content (author's transl)]

There is reported on the possibilities of diaplacental influencing on the DIC arising from the hypoxia we provoked with the help of an asphyxia model in rabbit fetuses. We could demonstrate the impossibility of influencing on the fetal vasal content by means of low molecular dextran, heparin or streptokinase. On the contrary, the possibility exists to influence on the fetal hemostasis by low molecular synthetic substances. The antifibrinolytic drug PAMBA causes in case of advanced acidosis diaplacental a definite growth of the intravascular coagulation, as well. But an inhibition of the fibrin sedimentation in the terminal vessels at the asphyctic shock can be achieved by applying the ethyl ester of the 4-amidinophenylpyruvic acid (APPA).

[Diaplacental inhibition of fetal blood coagulation in pregnant sheep (author's transl)]

We investigated the effect of the synthetic low-molecular thrombin inhibitor 4-amidinophenyl-pyruvic acid (APPA) on the maternal and fetal coagulation at 10 far advanced in pregnancy sheep. APPA inhibits as well the maternal as by diaplacental passage the fetal hemostasis in dependence on the dosage till the incoagulability. The effect in the fetal organism occurs after a delay of some minutes and wars of a bit earlier.

[Asphyxial shock and disseminated intravascular coagulation (DIC) in animal experiments. 1. Histological picture (author's transl)]

The effects of subacute intra-uterine hypoxia on the haemostatic system of 205 foetuses from 49 pregnant rabbits were studied by a standardised experimental arrangement, with particular reference being made to intravascular precipitation of fibrin. The asphyxial shock thus induced was accompanied by almost all the rabbit foetuses by disseminated intravascular coagulation by which the central organs were more strongly affected, as compared to peripheral organs also restricted by the shock. The pathophysiological processes which were found to take place in the lungs and placentas of the experimental animals proved different from those in man, which was attributable to species-related differences.