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| 6. |
- Muench, S., et al.
(författare)
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Time-resolved photoluminescence investigations on HfO2-capped InP nanowires
- 2010
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 21:10
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Tidskriftsartikel (refereegranskat)abstract
- We have employed time-resolved photoluminescence (PL) spectroscopy to study the impact of HfO2 surface capping by atomic layer deposition (ALD) on the optical properties of InP nanowires (NWs). The deposition of high-kappa dielectrics acting as a gate oxide is of particular interest in view of possible applications of semiconductor NWs in future wrap-gated field effect transistors (FETs). A high number of charged states at the NW-dielectrics interface can strongly degrade the performance of the FET which explains the strong interest in high quality deposition of high-kappa dielectrics. In the present work we show that time-resolved spectroscopy is a valuable and direct tool to monitor the surface quality of HfO2-capped InP NWs. In particular, we have studied the impact of ALD process parameters as well as surface treatment prior to the oxide capping on the NW-dielectrics interface quality. The best results in terms of the surface recombination velocity (S-0 = 9.5 x 10(3) cm s(-1)) were obtained for InP/GaP core/shell NWs in combination with a low temperature (100 degrees C) ALD process. While the present report focuses on the InP material system, our method of addressing the surface treatment for semiconductors with high-kappa dielectrics will also be applicable to nanoelectronic devices based on other III/V material systems such as InAs.
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| 9. |
- Appelros, Stefan, et al.
(författare)
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Activation peptide of carboxypeptidase B and anionic trypsinogen as early predictors of the severity of acute pancreatitis.
- 2001
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Ingår i: British Journal of Surgery. - : Oxford University Press (OUP). - 1365-2168 .- 0007-1323. ; 88:2, s. 216-221
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Tidskriftsartikel (refereegranskat)abstract
- Summary Background Early prediction of severity is important in the management of patients with acute pancreatitis. The presence of activation peptides and certain pancreatic proenzymes in plasma and urine has been shown to correlate with severity. This study was designed to assess the value of measuring levels of the activation peptide of carboxypeptidase B (CAPAP) and of anionic trypsinogen. Methods Concentrations of CAPAP and anionic trypsinogen were measured in the urine and serum in 60 patients with acute pancreatitis. Preset cut-off levels were used to analyse the accuracy of the tests. Severity was classified retrospectively according to the Atlanta classification. Results Concentrations of CAPAP in urine and serum and of anionic trypsinogen in urine correlated with the severity of the pancreatitis. CAPAP in urine showed the highest accuracy. The overall accuracy was 90 per cent, with a positive predictive value of 69 per cent and a negative predictive value of 98 per cent. Conclusion In this study, measurement of CAPAP in urine was an accurate way to predict the severity of acute pancreatitis, and was superior to assay of anionic trypsinogen in urine and serum. Measurement of CAPAP in urine may be of value in the management of individual patients with pancreatitis and in the selection of patients for therapeutic trials.
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| 11. |
- Borgström, Magnus, et al.
(författare)
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InAs quantum dots grown on InAlGaAs lattice matched to InP
- 2003
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Ingår i: Journal of Crystal Growth. - 0022-0248. ; 252:4, s. 481-485
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present InAs quantum dots prepared on an InxAlyGa1-x-yAs surface by metal organic vapor phase epitaxy. Atomic force microscopy measurements indicate that dots grown on material with higher Al content are smaller, and that the local dot densities on step-bunched facets formed on the vicinal (0 0 1) surfaces increase. We find that these dots show luminescence at very long wavelengths, lambda(room temperature) approximate to 2.1 mum, and that the emission wavelengths are blue-shifted when the Al content is increased in the layer onto which dot material is deposited. (C) 2003 Elsevier Science B.V. All rights reserved.
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| 13. |
- Borgström, S., et al.
(författare)
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Developing law for the bioeconomy
- 2016
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Ingår i: Journal of Energy and Natural Resources Law. - : Taylor and Francis Ltd.. - 0264-6811 .- 2376-4538. ; 34:4, s. 373-406
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Tidskriftsartikel (refereegranskat)abstract
- Development of a bioeconomy is seen to offer significant possibilities to address the challenges faced by a world with a growing population, resource scarcity, environmental degradation and climate change. The technical potential for a bioeconomy is impressive. It has been estimated that over 90 per cent of oil-based products could be replaced by bio-based alternatives. However, there are several challenges, uncertainties and concerns related to the development of a bioeconomy. These include potential negative effects of increased use of biomass on biodiversity and food production, as well as health and environmental risks associated with new biotechnologies. The urgency of the problems that a bioeconomy may provide solutions to and the new sustainability challenges emerging in a growing bioeconomy indicate the need to develop regulatory regimes that make the transition to a bioeconomy more rapid, controlled and sustainable. This article discusses the key issues in developing a bioeconomy that call for regulatory intervention. Further, it explores the need for development in regulatory approaches, strategies and structures for enabling the transition to and sustaining a bioeconomy and explains why, in theory, regulatory systems based on integrative, adaptive and proactive law approaches are a promising way to meet that need. © 2016 International Bar Association.
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| 14. |
- Carlberg, Patrick, et al.
(författare)
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Nanoimprint - a tool for realizing nano-bio research
- 2004
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Ingår i: 2004 4th IEEE Conference on Nanotechnology. - 0780385365 ; , s. 199-200
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present a status report on how implementation of nanoimprint lithography has advanced our research. Contact guidance nerve growth experiments have so far primarily been done on micrometer-structured surfaces. We have made a stamp with 17 areas of different, submicron, line width and spacing covering a total 2.6 mm
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| 15. |
- Dzhigaev, D., et al.
(författare)
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Bragg coherent x-ray diffractive imaging of a single indium phosphide nanowire
- 2016
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Ingår i: Journal of Optics. - : IOP Publishing. - 2040-8978 .- 2040-8986. ; 18:6
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Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional (3D) Bragg coherent x-ray diffractive imaging (CXDI) with a nanofocused beam was applied to quantitatively map the internal strain field of a single indium phosphide nanowire. The quantitative values of the strain were obtained by pre-characterization of the beam profile with transmission ptychography on a test sample. Our measurements revealed the 3D strain distribution in a region of 150 nm below the catalyst Au particle. We observed a slight gradient of the strain in the range of 0.6% along the [111] growth direction of the nanowire. We also determined the spatial resolution in our measurements to be about 10 nm in the direction perpendicular to the facets of the nanowire. The CXDI measurements were compared with the finite element method simulations and show a good agreement with our experimental results. The proposed approach can become an effective tool for in operando studies of the nanowires.
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| 16. |
- Erixon, Hanna, et al.
(författare)
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Challenging dichotomies : exploring resilience as an integrative and operative conceptual framework for large-scale urban green structures
- 2013
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Ingår i: Planning Theory & Practice. - : Informa UK Limited. - 1464-9357 .- 1470-000X. ; 14:3, s. 349-372
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Tidskriftsartikel (refereegranskat)abstract
- Urban planners and urban planning as a field face a major challenge in balancing urban development interests against the need to safeguard socially equitable and ecologically functional green space. This need is still commonly seen through a modernist lens, whereby large-scale green areas are viewed as an antithesis to the city, creating a polarised landscape seemingly free from cross-scale social and ecological interactions. This study reports on a transdisciplinary work process that aimed to challenge this polarisation by exploring more integrative and operative planning approaches to large-scale urban green structures, using the concept of resilience, both as a theoretical umbrella and in relation to a case study in Stockholm, Sweden. The exploration took the form of a series of workshops in which professionals from the fields of planning, urban design, ecology, landscape architecture, and environmental history, as well as city-wide and regional planning, took part. Throughout the process, tentative designs served as "touchstones", bringing questions from a theoretical level to a hands-on, specific, local context. This paper identifies three ways that resilience science can be useful in the planning and management of large urban green structures. Firstly, resilience can introduce complexity and thus make visible synergies and "win-win" situations within planning. Secondly, in highlighting change, resilience can offer alternatives to present conservationist perspectives on green space planning and thus offer constructive ways out of planning-related deadlocks. Thirdly, resilience can be advantageously combined with the concept of "legibility" in clarifying common goals and thus helping to build a constituency which will sustain large-scale green structures over time.
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| 17. |
- Espinet-Gonzalez, Pilar, et al.
(författare)
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Radiation Tolerant Nanowire Array Solar Cells
- 2019
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 13:11, s. 12860-12869
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Tidskriftsartikel (refereegranskat)abstract
- Space power systems require photovoltaics that are lightweight, efficient, reliable, and capable of operating for years or decades in space environment. Current solar panels use planar multijunction, III-V based solar cells with very high efficiency, but their specific power (power to weight ratio) is limited by the added mass of radiation shielding (e.g., coverglass) required to protect the cells from the high-energy particle radiation that occurs in space. Here, we demonstrate that III-V nanowire-array solar cells have dramatically superior radiation performance relative to planar solar cell designs and show this for multiple cell geometries and materials, including GaAs and InP. Nanowire cells exhibit damage thresholds ranging from ∼10-40 times higher than planar control solar cells when subjected to irradiation by 100-350 keV protons and 1 MeV electrons. Using Monte Carlo simulations, we show that this improvement is due in part to a reduction in the displacement density within the wires arising from their nanoscale dimensions. Radiation tolerance, combined with the efficient optical absorption and the improving performance of nanowire photovoltaics, indicates that nanowire arrays could provide a pathway to realize high-specific-power, substrate-free, III-V space solar cells with substantially reduced shielding requirements. More broadly, the exceptional reduction in radiation damage suggests that nanowire architectures may be useful in improving the radiation tolerance of other electronic and optoelectronic devices.
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| 18. |
- Flodgren, P, et al.
(författare)
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Immune functions in melanoma patients during treatment with interferon [HuIFN-alpha (Le)] alone or in combination with cimetidine
- 1985
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Ingår i: Anticancer research. - 0250-7005. ; 5:2, s. 197-204
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Tidskriftsartikel (refereegranskat)abstract
- While leukocyte interferon was found therapeutically ineffective in a series of 20 patients with metastatic malignant melanoma, subsequent combination treatment with interferon and cimetidine induced 5 complete and 1 partial tumour remissions. Prior to interferon therapy initiation, regressor patients demonstrated a significantly greater ability to mediate antibody-dependent cellular cytotoxicity than progressor patients and also tended to have higher natural killer-cell activity. These differences were more pronounced following in vitro exposure of effector cells to interferon alone or in combination with cimetidine. During therapy the differences decreased to statistically nonsignificant levels. The number of immunoglobulin producing cells and lymphocyte proliferative responses to Con A were found to increase in both patient groups after interferon therapy initiation; but this augmentation vanished gradually upon combined treatment with cimetidine. A gradual decrease of the number of T lymphocytes and granulocytes was also recorded. None of the demonstrated alterations in the activities of circulating lymphocytes appears to be a relevant correlate to the efficacy of combined therapy compared to interferon alone.
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| 19. |
- Göransson, D. J.O., et al.
(författare)
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Coulomb blockade from the shell of an InP-InAs core-shell nanowire with a triangular cross section
- 2019
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 114:5
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Tidskriftsartikel (refereegranskat)abstract
- We report on growth of InP-InAs core-shell nanowires and demonstration of the formation of single quantum structures, which show the Coulomb blockade effect, over entire lengths of the nanowires. The core-shell nanowires are grown by a selective area growth technique via metal-organic vapor phase epitaxy. The as-grown core-shell nanowires are found to be of wurtzite crystals. The InP cores have a hexagonal cross section, while the InAs shells are grown preferentially on specific { 1 1 ¯ 00} facets, leading to the formation of the core-shell nanowires with an overall triangular cross section. The grown core-shell nanowires are transferred onto a Si/SiO 2 substrate and then contacted by several narrow metal electrodes. Low-temperature transport measurements show the Coulomb-blockade effect. We analyze the measured gate capacitance and single electron charging energy of the devices and demonstrate that a quantum structure which shows the Coulomb blockade effect of a many-electron quantum dot is formed over the full length of a single core-shell nanowire and consists of the entire InAs shell in the nanowire.
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| 20. |
- Gössling, Stefan, et al.
(författare)
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Ecological footprint analysis as a tool to assess tourism sustainability
- 2002
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Ingår i: Ecological Economics. - 0921-8009. ; 43:2-3, s. 199-211
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Tidskriftsartikel (refereegranskat)abstract
- This article has the aim to provide a methodological framework for the calculation of ecological footprints related to leisure tourism. Based on the example of the Seychelles, it reveals the statistical obstacles that have to be overcome in the calculation process and discusses the strengths and weaknesses of such an approach. As many tropical island-states depend heavily on foreign exchange earnings derived from visitors arriving by air, special attention is paid to the use of energy associated with air travel. Furthermore, implications of the findings for national greenhouse inventories are discussed. Finally, as the Seychelles have safeguarded a wide range of ecosystems in protected areas, which are for their existence ultimately dependent on financial resources derived from tourism, the question is raised if long-distance travel can be a means to safeguard biodiversity. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 22. |
- Mergenthaler, K., et al.
(författare)
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Anti-Stokes photoluminescence probing k-conservation and thermalization of minority carriers in degenerately doped semiconductors
- 2017
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- It has recently been found that anti-Stokes photoluminescence can be observed in degenerately n-doped indium phosphide nanowires, when exciting directly into the electron gas. This anti-Stokes mechanism has not been observed before and allows the study of carrier relaxation and recombination using standard photoluminescence techniques. It is important to know if this anti-Stokes photoluminescence also occurs in bulk semiconductors as well as its relation to carrier recombination and relaxation. Here we show that similar anti-Stokes photoluminescence can indeed be observed in degenerately doped bulk indium phosphide and gallium arsenide and is caused by minority carriers scattering to high momenta by phonons. We find in addition that the radiative electron-hole recombination is highly momentum-conserving and that photogenerated minority carriers recombine before relaxing to the band edge at low temperatures. These observations challenge the use of models assuming thermalization of minority carriers in the analysis of highly doped devices.
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| 23. |
- Paju, A, et al.
(författare)
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Expression and characterization of trypsinogen produced in the human male genital tract
- 2000
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Ingår i: American Journal of Pathology. - 1525-2191. ; 157:6, s. 2011-2021
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Tidskriftsartikel (refereegranskat)abstract
- Trypsinogen is a serine proteinase produced mainly by the pancreas, but it has recently been found to be expressed also in several cancers such as ovarian and colon cancer and in vascular endothelial cells. In this study, we found that trypsinogen-1 and -2 are present at high concentrations (median levels, 0.4 and 0.5 mg/L, respectively) in human seminal fluid and purified them to homogeneity by immunoaffinity and anion exchange chromatography. Purified trypsinogen isoenzymes displayed a M(r) of 25 to 28 kd in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting. Most of the trypsinogen-1 purified from seminal fluid was enzymatically active whereas trypsinogen-2 occurred as the proform, which could be activated by enteropeptidase in vitro. Immunohistochemically, trypsinogen protein was detected in the human prostate, urethra, utriculus, ejaculatory duct, seminal vesicles, deferent duct, epididymal glands, and testis. Expression of trypsinogen mRNA in the same organs was demonstrated by in situ hybridization. Trypsinogen mRNA was also detected in the prostate and seminal vesicles by reverse transcriptase-polymerase chain reaction and Northern blotting. Isolated trypsin was shown to activate the proenzyme form of prostate-specific antigen. These results suggest that trypsinogen isoenzymes found in seminal fluid are produced locally in the male genital tract and that they may play a physiological role in the semen.
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| 24. |
- Svensäter, Gunnel, et al.
(författare)
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The acid-tolerant microbiota associated with plaque from initial caries and healthy tooth surfaces
- 2003
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Ingår i: Caries Research. - : S. Karger AG. - 0008-6568 .- 1421-976X. ; 37:6, s. 395-403
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The intent of this study was to compare the inherent acid tolerance of bacteria in samples of dental plaque from tooth sites in subjects with and without initial caries. Plaque was collected from approximal surfaces showing early enamel caries and from healthy tooth surfaces in the same subjects, as well as from enamel surfaces of caries-free individuals. In addition to plating on blood agar, the plaque samples were plated directly on non-selective solid agar medium buffered to pH 7.0, 6.0, 5.5, 5.0, 4.5 and 4.0 to avoid any loss of adaptation to acid during primary isolation of plaque bacteria. The results showed that approximately 50% of the total cultivable plaque microbiota from caries, as well as healthy tooth sites, was able to grow at pH 5.5 and 1% at pH 5.0, pH values regarded as critical for the demineralization of tooth enamel. At pH 5.0, members of the genus Streptococcus were the dominant group, but mutans streptococci accounted for less than half of the streptococcal viable count. The other acid-tolerant streptococcal isolates included Streptococcus anginosus, Streptococcus constellatus, Streptococcus gordinii, Streptococcus intermedius, Streptococcus mitis, Streptococcus oralis, Streptococcus salivarius and SStreptococcus sanguis. Analysis of the results indicated that the mutans streptococci in dental plaque were highly variable with respect to acid tolerance, and that both caries and healthy sites harboured significant numbers of mutans streptococci that were not acid-tolerant.
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| 26. |
- Woksepp, Hanna, et al.
(författare)
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High target attainment for beta-lactam antibiotics in intensive care unit patients when actual minimum inhibitory concentrations are applied
- 2017
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Ingår i: European Journal of Clinical Microbiology and Infectious Diseases. - Heidelberg : Springer. - 0934-9723 .- 1435-4373. ; 36:3, s. 553-563
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Tidskriftsartikel (refereegranskat)abstract
- Patients in the intensive care unit (ICU) are at risk for suboptimal levels of beta-lactam antibiotics, possibly leading to poor efficacy. Our aim was to investigate whether the actual minimum inhibitory concentration (MIC) compared to the more commonly used arbitrary epidemiological cut-off values (ECOFFs) would affect target attainment in ICU patients on empirical treatment with broad-spectrum beta-lactam antibiotics and to identify risk factors for not reaching target. In a prospective, multicenter study, ICU patients ae18 years old and treated with piperacillin/tazobactam, meropenem, or cefotaxime were included. Clinical and laboratory data were recorded. Serum trough antibiotic levels from three consecutive days were analyzed by liquid chromatography-mass spectrometry (LC-MS). The target was defined as the free trough concentration above the MIC (100% fT(> MIC)). MICECOFF was used as the target and, when available, the actual MIC (MICACTUAL) was applied. The median age of the patients was 70 years old, 52% (58/111) were males, and the median estimated glomerular filtration rate (eGFR) was 48.0 mL/min/1.73 m(2). The rate of patients reaching 100% fT > MICACTUAL was higher (89%, 31/35) compared to the same patients using MICECOFF (60%, p = 0.002). In total, 55% (61/111) reached 100% fT > MICECOFF. Increased renal clearance was independently associated to not reaching 100% fT > MICECOFF. On repeated sampling, > 77% of patients had stable serum drug levels around the MICECOFF. Serum concentrations of beta-lactam antibiotics vary extensively between ICU patients. The rate of patients not reaching target was markedly lower for the actual MIC than when the arbitrary MIC based on the ECOFF was used, which is important to consider in future studies.
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