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- Shamrai, K P, et al.
(författare)
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Discharge disruptions in a helicon plasma source
- 1997
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Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : American Vacuum Society. - 0734-2101 .- 1520-8559. ; 15:6, s. 2864-2874
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Tidskriftsartikel (refereegranskat)abstract
- We study experimentally and theoretically stable regimes and dischargedisruptions in a helicon plasma source. At fixed input power and gas pressure, stable operation of the source is possible below some critical value of magnetic field Bcr." role="presentation" style="display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">Bcr.Bcr. The plasma density increases with the magnetic field and reaches a maximum value nmax" role="presentation" style="display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">nmaxnmax at Bcr;" role="presentation" style="display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">Bcr;Bcr; after which the discharge disruption occurs. Both Bcr" role="presentation" style="display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">BcrBcr and nmax" role="presentation" style="display: inline; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">nmaxnmax increase almost linearly with the input power and the rate of increase is increasing with the pressure. Matching of the plasma load to the rf power source improves when approaching the disruption point, and becomes perfect at the critical field. The theory of discharge disruptions assumes the power absorption in a helicon source to arise from the linear conversion of helicon waves into electrostatic waves at the plasma edge. The calculated dependence of the absorbed power on the plasma density turns out to be nonmonotonic with minima at antiresonances of the electrostatic waveexcitation. This explains qualitatively principal peculiarities of dischargedisruptions. The calculated plasma impedance is in agreement with experimental value within a factor of 2.
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| 2. |
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| 3. |
- Kullander, Sven, et al.
(författare)
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Rare eta decays and the CP symmetry
- 1998
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Ingår i: ACTA PHYSICA POLONICA B. - : ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS. - 0587-4254. ; 29:1-2, s. 97-111
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Tidskriftsartikel (refereegranskat)abstract
- Among the light mesons, the eta is very well suited for tests of the Standard Model (SM). Besides its negative parity and predominantly SU(3) octet structure, the eta has the quantum numbers of the vacuum, it is comparatively massive and it is long-lived
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| 4. |
- Denmeade, Samuel R., et al.
(författare)
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Enzymatic activation of a doxorubicin-peptide prodrug by prostate- specific antigen
- 1998
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Ingår i: Cancer Research. - 0008-5472. ; 58:12, s. 2537-2540
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Tidskriftsartikel (refereegranskat)abstract
- New approaches to target cytotoxic therapy specifically to metastatic prostate cancer sites are urgently needed. As such an approach, an inactive prodrug was synthesized by coupling the primary amine of doxorubicin to the COOH-terminal carboxyl of a seven-amino acid peptide carrier (i.e., Mu-His- Ser-Ser-Lys-Leu-Gln-Leu). The seven-amino acid peptide was documented to be hydrolyzable specifically by the serine protease prostate-specific antigen (PSA) to liberate the active cytotoxin L-leucyl-doxorubicin. Primary cultures of PC-82 human prostate cancer cells secreted high levels of enzymatically active PSA (i.e., 70 ± 5 ng of enzymatically active PSA/106 cells/24 h), whereas LNCaP human prostate cancer ells produced lower levels of enzymatically active PSA (i.e., 2.3 ± 1 ng/106 cells/24 h). LNCaP cells, however, secreted sufficient amounts of enzymatically active PSA to activate the doxorubicin prodrug to a cytotoxic form in vitro. The specificity of the cytotoxic response to the prodrug was demonstrated by the fact that 70 nM of the prodrug killed 50% of the PSA-producing LNCaP cells, whereas doses as high as 1 ♂ had no cytotoxic effect on PSA-nonproducing TSU human prostate cancer cells in vitro.
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| 5. |
- Luhr, O., et al.
(författare)
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A retrospective analysis of nitric oxide inhalation in patients with severe acute lung injury in Sweden and Norway 1991-1994
- 1997
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 41:10, s. 1238-46
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Patients with severe acute lung injury (ALI) have been treated compassionately on doctors' initiative with inhaled nitric oxide (INO) in Sweden and Norway since 1991. In 1994 the previously used technical grade nitric oxide was replaced by medical grade nitric oxide. METHODS: We have carried out a retrospective data collection on all identified adult patients treated with INO for >4 h during the period 1991-1994 focusing on safety aspects and patient outcome. We used the following exclusion criteria (1) Age <18 years, (2) Simultaneous treatment with extracorporeal removal of CO2 (3) NO inhalation period <4 h, (4) Incomplete or missing patient charts, (5) Use of INO in order to treat pulmonary hypertension following cardiac surgery, with little or no acute lung injury. RESULTS: Inclusion criteria were met by 56 out of 73 identified patients. Mean age was 48+/-19 years and the median duration of INO treatment was 102 h. PaO2/FIO2 ratio at start of treatment was 85 +/- 33 mm Hg with a lung injury score (LIS) of 3.2+/-0.8. The aetiology of the lung injury was pneumonia (n= 27), sepsis (n=12) and trauma (n=8). Survival to hospital discharge was 41% and survival after 180 d was 38%. Three serious adverse events were identified, two from technical failures of the INO delivery device and one withdrawal reaction necessitating slow weaning from INO. No methaemoglobin values >5% were reported during treatment. CONCLUSION: The overall mortality did not differ dramatically from historical controls with high mortality. Only a randomised study may determine whether INO as an adjunct to treatment alters the outcome in severe ALI. One cannot at present advocate the routine use of INO in patients with ALI outside such studies.
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| 8. |
- Åkerstedt, Hans O., et al.
(författare)
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Three-dimensional stability of drift vortices
- 1996
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 3:1, s. 160-167
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Tidskriftsartikel (refereegranskat)abstract
- The three-dimensional stability of drift vortices that are two-dimensionally stable in the framework of the Hasegawa-Mima equation is studied. The three-dimensionality is caused by a coupling of the vortex to ion-acoustic waves that propagate along the magnetic field. It is concluded that this coupling does not significantly destabilize the vortex. A general stability criterion is derived that guarantees stability if the ratio between the parallel wave number k and the azimuthal mode number m is large enough. It is also found that no instability exists in the limit k→ 0 if the potential vorticity is a strictly decreasing function of r. Such profiles are typical for vortices that are two-dimensionally stable. Some particular profiles where the potential vorticity vanishes outside some radius are also examined. In one case an instability with m=1 is found, but a numerical solution of the eigenvalue problem shows that the maximum growth rate is very small, three orders of magnitude smaller than the angular velocity of the vortex flow.
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