| 1. |
- Linnarsson, M K, et al.
(författare)
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Precipitate formation in heavily Al-doped 4H-SiC layers
- 2001
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Ingår i: Materials Science Forum, Vols. 353-356. ; , s. 583-586, s. 583-586
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Konferensbidrag (refereegranskat)abstract
- Epitaxially grown 4H-SiC structures with several heavily Al doped layers were used. The samples were annealed in Ar atmosphere in a RF-heated furnace between 1500 and 2900 degreesC for 0.5 to 3h. Secondary ion mass spectrometry (SIMS) was used to measure the aluminum concentration versus,depth as well as the lateral distribution (ion images). Transmission electron microscopy (TEM) was employed to study the crystallinity and determine phase composition after heat treatment. A solubility limit of 2x10(20) Al/cm(3) at 2000 degreesC is extracted. Ion images of the lateral Al distribution reveal a pronounced dependence on the Al content. Precipitate formation occurs after heat treatment at 1700 - 2000 degreesC when the Al concentration exceeds 2x10(20) cm(-3) and energy-filtered TEM (EFTEM) shows that the precipitates contain Al.
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| 2. |
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| 3. |
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| 4. |
- Holmlund, F, et al.
(författare)
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Sympathetic skin vasoconstriction--further evaluation using laser Doppler techniques
- 2001
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Ingår i: Clinical Physiology. - : Wiley. - 1365-2281 .- 0144-5979. ; 21:3, s. 287-291
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to quantify the reflex sympathetic vasoconstriction in skin at different depths. Twenty healthy subjects were studied. Finger skin blood flow was measured using laser Doppler perfusion imaging (LDPI) and laser Doppler perfusion monitoring (LDPM). In LDPM, a probe with fibres separated 0.25 mm (deep) and 0.14 mm (superficial) from the illuminating fibre was used. Local heating (40 degrees C) was achieved with a Peltier element, and reflex vasoconstriction induced by immersion of the contra-lateral hand and forearm for 3 min in water at 15 degrees C. The change in skin blood flow was measured and a vasoconstriction index (VAC: cooling/before cooling) calculated. VAC indices of LDPI, LDPM-0.25 and LDPM-0.14 were 0.60, 0.59 and 0.60, respectively. The two components of the LDPM perfusion value, blood cell velocity and concentration, were studied separately. Their contributions in LDPM-0.25 were roughly the same, whereas the velocity component dominated in LDPM-0.14, although their relative responses in the two channels were similar. We conclude that sympathetic skin vasoconstriction does not significantly differ in two compartments, as probed with fibres separated by 0.25 and 0.14 mm. Blood cell velocity is influenced in a proportional way, as is concentration.
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| 5. |
- Håkansson, M., et al.
(författare)
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The crystal structure of staphylococcal enterotoxin H : Implications for binding properties to MHC class II and TcR molecules
- 2000
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Ingår i: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836. ; 302:3, s. 527-537
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Tidskriftsartikel (refereegranskat)abstract
- The X-ray structure of the superantigen staphylococcal enterotoxin H (SEH) has been determined at 1.69 Å resolution. In this paper we present two structures of zinc-free SEH (apoSEH) and one zinc-loaded form of SEH (ZnSEH). SEH exhibits the conventional superantigen (SAg) fold with two characteristic domains. In ZnSEH one zinc ion per SEH molecule is bound to the C-terminal β-sheet in the region implicated for major histocompatibility complex class II (MHC class II) binding in SEA, SED and SEE. Surprisingly, the zinc ion has only two ligating amino acid residues His206 and Asp208. The other ligands to the zinc ion are two water molecules. An extensive packing interaction between two symmetry-related molecules in the crystal, 834 Å2/molecule, forms a cavity that buries the zinc ions of the molecules. This dimer-like interaction is found in two crystal forms. Nevertheless, zinc-dependent dimerisation is not observed in solution, as seen in the case of SED. A unique feature of SEH as compared to other staphylococcal enterotoxins is a large negatively charged surface close to the Zn2+ site. The interaction of SEH with MHC class II is the strongest known among the staphylococcal enterotoxins. However, SEH seems to lack a SEB-like MHC class II binding site, since the side-chain properties of structurally equivalent amino acid residues in SEH and those in SEB-binding MHC class II differ dramatically. There is also a structural flexibility between the domains of SEH. The domains of two apoSEH structures are related by a 5°rotation leading to at most 3 Å difference in C(α) positions. Since the T-cell receptor probably interacts with both domains, SEH by this rotation may modulate its binding to different TcR Vβ-chains. (C) 2000 Academic Press.
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| 6. |
- Kloo, Lars, et al.
(författare)
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On the Intra- and Intermolecular Bonding in Polyiodides
- 2002
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Ingår i: European Journal of Inorganic Chemistry. - 1434-1948 .- 1099-1948. ; :5, s. 1203-1209
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Tidskriftsartikel (refereegranskat)abstract
- The nature of intra- and intermolecular interactions of poly-iodides has been investigated by means of quantum chemical methods and structural statistical data. In the region of "secondary bonds" the interaction is adequately described in terms of covalent bonding accompanied by dispersion. At greater distances the interaction is dominated by ion-quadrupole interactions between ionic and neutral iodine building blocks of the polyiodide structures.
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| 7. |
- Linnarsson, Margareta K., et al.
(författare)
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Solubility limit and precipitate formation in Al-doped 4H-SiC epitaxial material
- 2001
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 79:13, s. 2016-2018
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Tidskriftsartikel (refereegranskat)abstract
- Heavily Al-doped 4H-SiC structures have been prepared by vapor phase epitaxy. Subsequent anneals have been carried out in an Ar atmosphere in a rf-heated furnace between 1500 degreesC and 2000 degreesC for 0.5 to 3 h. Secondary ion mass spectrometry has been utilized to obtain Al concentration versus depth as well as lateral distributions (ion images). Transmission electron microscopy (TEM) has been employed to study the crystallinity and determine phase composition after heat treatment. A solubility limit of similar to 2x10(20) Al/cm(3) (1900 degreesC) is extracted. Three-dimensional ion images show that the Al distribution does not remain homogeneous in layers heat treated at 1700 degreesC or above when the Al concentration exceeds 2x10(20) cm(-3). Al-containing precipitates are identified by energy-filtered TEM.
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| 8. |
- Malmström, Per, et al.
(författare)
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Breast conservation surgery, with and without radiotherapy, in women with lymph node-negative breast cancer: a randomised clinical trial in a population with access to public mammography screening.
- 2003
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Ingår i: European journal of cancer (Oxford, England : 1990). - 0959-8049. ; 39, s. 1690-
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Tidskriftsartikel (refereegranskat)abstract
- The effect of postoperative radiotherapy after sector resection for stage I-II lymph node-negative breast cancer was evaluated in a patient population with access to public mammographical screening. 1187 women were randomised to no further treatment or postoperative radiotherapy following a standardised sector resection and axillary dissection. Radiation was administered to a dose of 48-54 Gy. Median age was 60 years, and median size of the detected tumours was 12 mm. Of the women 65% had their tumours detected by mammographical screening. The relative risk (RR) of ipsilateral breast recurrence was significantly higher in the non-irradiated patients compared with the irradiated patients, RR=3.33 (95% Confidence Interval (CI) 2.13-5.19, P<0.001). The corresponding cumulative incidence at 5 years was 14% versus 4%, respectively. Overall survival (OS) was similar, RR=1.16 (95% CI 0.81-1.65, P=0.41), with 5 year probabilities of 93 and 94%, respectively. Recurrence-free survival (RFS) at 5 years was significantly lower in the non-irradiated women, 77% versus 88% (P<0.001). Although women above 49 years of age, whose tumours were detected with mammographical screening, had the lowest rate of ipsilateral breast recurrence in this study, the cumulative incidence of such event amounted to 10% at 5 years if radiotherapy was not given. Such a recurrence rate has been considered as unacceptably high, but is, however, in the same range as that reported after lumpectomy and postoperative radiotherapy in published series.
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| 9. |
- Svanberg, B, et al.
(författare)
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Isolation of differentially expressed aldose reductase in ovaries after estrogen withdrawal from hypophysectomized diethylstilbestrol treated rats: increased expression during apoptosis.
- 2000
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Ingår i: Molecular and cellular endocrinology. - 0303-7207. ; 164:1-2, s. 183-90
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Tidskriftsartikel (refereegranskat)abstract
- More than 99% of the follicles are eliminated by apoptosis before reaching ovulation. Several growth factors and hormones inhibit apoptosis in the ovary, including estrogen. Using differential display of mRNA, aldose reductase was shown to increase in the ovary of diethylstilbestrol treated hypophysectomized rats after estrogen withdrawal, inducing apoptosis. The aldose reductase mRNA expression was confirmed to be 2.2 +/- 0.2-fold higher after estrogen withdrawal using northern blot analysis. In addition, untreated immature rats showed a 1.7 +/- 0.3-fold higher expression of ovarian aldose reductase mRNA compared to ovaries 24 h after pregnant mare's serum gonadotropin treatment, decreasing apoptosis in the ovary. In the prostate, the level of aldose reductase was increased 3.1 +/- 1.1-fold 2 days after castration induced apoptosis. Although the physiological role of aldose reductase in the ovary is not known, these data suggest that aldose reductase may be part of a hormonally regulated apoptotic pathway in the ovary and prostate.
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