| 1. |
- Lind, Erik, et al.
(författare)
-
Improved subthreshold slope in an InAs nanowire heterostructure field-effect transistor
- 2006
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 6:9, s. 1842-1846
-
Tidskriftsartikel (refereegranskat)abstract
- An n-type InAs/InAsP heterostructure nanowire field-effect transistor has been fabricated and compared with a homogeneous InAs field-effect transistor. For the same device geometry, by introduction of the heterostructure, the threshold voltage is shifted 4 V, the maximum current on-off ratio is enhanced by a factor of 10 000, and the subthreshold swing is lowered by a factor 4 compared to the homogeneous transistor. At the same time, the drive current remains constant for a fixed gate overdrive. A single nanowire heterostructure transistor has a transconductance of 5 mu A/V at a low source-drain voltage of 0.3 V. For the homogeneous InAs transistor, we deduced a high electron mobility of 1500 cm(2)/Vs.
|
|
| 2. |
- Carlsson, Jörgen, et al.
(författare)
-
Planning for intracavitary anti-EGFR radionuclide therapy of gliomas : Literature review and data on EGFR expression
- 2006
-
Ingår i: Journal of Neuro-Oncology. - : Springer Science and Business Media LLC. - 0167-594X .- 1573-7373. ; 77:1, s. 33-45
-
Tidskriftsartikel (refereegranskat)abstract
- Targeting with radionuclide labelled substances that bind specifically to the epidermal growth factor receptor, EGFR, is considered for intracavitary therapy of EGFR-positive glioblastoma multiforme, GBM. Relevant literature is reviewed and examples of EGFR expression in GBM are given. The therapeutical efforts made so far using intracavitary anti-tenascin radionuclide therapy of GBM have given limited effects, probably due to low radiation doses to the migrating glioma cells in the brain. Low radiation doses might be due to limited penetration of the targeting agents or heterogeneity in the expression of the target structure. In this article we focus on the possibilities to target EGFR on the tumour cells instead of an extracellular matrix component. There seems to be a lack of knowledge on the degree of intratumoral variation of EGFR expression in GBM, although the expression seemed rather homogeneous over large areas in most of the examples (n=16) presented from our laboratory. The observed homogeneity was surprising considering the genomic instability and heterogeneity that generally characterises highly malignant tumours. However, overexpression of EGFR is, at least in primary GBMs, one of the steps in the development of malignancy, and tumour cells that lose or downregulate EGFR will probably be outgrown in an expanding tumour cell population. Thus, loss of EGFR expression might not be the critical factor for successful intracavitary radionuclide therapy. Instead, it is likely that the penetration properties of the targeting agents are critical, and detailed studies on this are urgent.
|
|
| 3. |
- Henriksnäs, Johanna, 1973-
(författare)
-
Helicobacter pylori and Gastric Protection Mechanisms : An in vivo Study in Mice and Rats
- 2005
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The stomach is frequently exposed to hazardous agents and to resist this harsh environment, several protective mechanisms exist. Of special interest is the gastric pathogen Helicobacter pylori which causes gastritis, ulcers and cancer but the mechanism leading to these diseases are still unclear. However it is very likely that H. pylori negatively influence the protection mechanisms that exist in the stomach. The aims of the present investigation were first to develop an in vivo mouse model in which different protection mechanisms could be studied, and second to investigate the influence of H. pylori on these mechanisms. An in vivo preparation of the gastric mucosa in mice was developed. This preparation allows studies of different gastric mucosal variables and can also be applied for studies in other gastro-intestinal organs. Mice chronically infected with H. pylori, were shown to have a reduced ability of the mucosa to maintain a neutral pH at the epithelial cell surface. This could be due to the thinner inner, firmly adherent mucus gel layer, and/or to defective bicarbonate transport across the epithelium. The Cl-/HCO3- exchanger SLC26A9 was inhibited by NH4+, which also is produced by H. pylori. The mRNA levels of SLC26A9 were upregulated in infected mice, suggesting a way to overcome the inhibition of the transporter. Furthermore, the hyperemic response to acid pH 2 and 1.5 was abolished in these mice. The mechanisms by which the bacteria could alter the blood flow response might involve inhibition of the epithelial iNOS.Water extracts of H. pylori (HPE) reduces the blood flow acutely through an iNOS and nerve-mediated pathway, possibly through the endogenous iNOS inhibitor ADMA. Furthermore, HPE alters the blood flow response to acid as the hyperemic response to acid pH 0.8 is accentuated in mice treated with HPE.
|
|
| 4. |
- Lind, Erik, et al.
(författare)
-
Band Structure Effects on the Scaling Properties of [111] InAs Nanowire MOSFETs
- 2009
-
Ingår i: IEEE Transactions on Electron Devices. - 0018-9383. ; 56:2, s. 201-205
-
Tidskriftsartikel (refereegranskat)abstract
- We have investigated the scaling properties of [111] InAs nanowire MOSFETs in the ballistic limit. The nanowire band structure has been calculated with an Sp(3)d(5)s* tight-binding model for nanowire diameters between 2 and 25 nm. Both the effective band gap and the effective masses increase with confinement. Using the atomistic dispersion relations, the ballistic currents and corresponding capacitances have been calculated with a semianalytical model. It is shown that the InAs nanowire MOSFET with diameters scaled below 15-20 nm can be expected to operate close to the quantum capacitance limit, assuming a high-kappa dielectric thickness of 1-1.5 nm. We have also investigated the evolution of f (t) and the gate delay, both showing improvements as the device is scaled. The very small intrinsic gate capacitance in the quantum limit makes the device susceptible to parasitic capacitances.
|
|
| 5. |
- Persson, Christina, et al.
(författare)
-
Interleukin 1-beta gene polymorphisms and risk of gastric cancer in Sweden.
- 2009
-
Ingår i: Scandinavian journal of gastroenterology. - : Informa UK Limited. - 1502-7708 .- 0036-5521. ; 44:3, s. 339-45
-
Tidskriftsartikel (refereegranskat)abstract
- Helicobacter pylori (H. pylori) infection stimulates the production of interleukin (IL)-1 beta, a pro-inflammatory cytokine and suppressor of gastric acid secretion. As both inflammation and hypochlorhydria, which might facilitate proximal colonization of H. pylori and other bacterial species alike, have been implicated in gastric carcinogenesis, much attention has been directed to functional genetic polymorphisms that affect the production of IL-1 beta. The purpose of this study was to clarify the role of these polymorphisms.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Abramovich, Shoshana, et al.
(författare)
-
General inequalities via isotonic subadditive functionals
- 2007
-
Ingår i: Mathematical Inequalities & Applications. - : Element d.o.o.. - 1331-4343 .- 1848-9966. ; 10:1, s. 15-28
-
Tidskriftsartikel (refereegranskat)abstract
- In this manuscript a number of general inequalities for isotonic subadditive functionals on a set of positive mappings are proved and applied. In particular, it is pointed out that these inequalities both unify and generalize some general forms of the Holder, Popoviciu, Minkowski, Bellman and Power mean inequalities. Also some refinements of some of these results are proved.
|
|
| 9. |
- Algervik, Robert, 1981-
(författare)
-
Embedding Theorems for Mixed Norm Spaces and Applications
- 2008
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is devoted to the study of mixed norm spaces that arise in connection with embeddings of Sobolev and Besov type spaces. The work in this direction originates in a paper due to Gagliardo (1958), and was continued by Fournier (1988) and by Kolyada (2005). We consider fully anisotropic mixed norm spaces. Our main theorem states an embedding of these spaces into Lorentz spaces. Applying this result, we obtain sharp embedding theorems for anisotropic fractional Sobolev spaces and anisotropic Sobolev-Besov spaces. The methods used are based on non-increasing rearrangements and on estimates of sections of functions and sections of sets. We also study limiting relations between embeddings of spaces of different type. More exactly, mixed norm estimates enable us to get embedding constants with sharp asymptotic behaviour. This gives an extension of the results obtained for isotropic Besov spaces $B_p^\alpha$ by Bourgain, Brezis, and Mironescu, and for Besov spaces $B^{\alpha_1,\dots,\alpha_n}_p$ by Kolyada. We study also some basic properties (in particular the approximation properties) of special weak type spaces that play an important role in the construction of mixed norm spaces and in the description of Sobolev type embeddings.
|
|
| 10. |
|
|
