| 1. |
- Ahmed, M., et al.
(författare)
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Search for the lepton-family-number nonconserving decay μ +→e +γ
- 2002
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Ingår i: Physical Review D. - : American Physical Society. - 1550-7998 .- 1550-2368. ; 65:11
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Tidskriftsartikel (refereegranskat)abstract
- The MEGA experiment, which searched for the muon- and electron-number violating decay μ +→e + γ, is described. The spectrometer system, the calibrations, the data taking procedures, the data analysis, and the sensitivity of the experiment are discussed. The most stringent upper limit on the branching ratio, B(μ + →e + γ)<1.2×10 -11 with 90% confidence, is derived from a likelihood analysis.
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| 2. |
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| 3. |
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| 4. |
- Grubbström, Robert W., 1941-, et al.
(författare)
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An Overview of Input-Output Analysis Applied to Production-Inventory Systems
- 2000
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Ingår i: Economic Systems Research. - : Informa UK Limited. - 0953-5314 .- 1469-5758. ; 12:1, s. 3-25
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Tidskriftsartikel (refereegranskat)abstract
- Input-Output Analysis, together with the Laplace transform, have been applied to multi-level, multi-period production-inventory systems in a number of papers. This article gives a historical overview of the areas involved in these studies. It is shown that the input and output matrices as well as the Leontief inverse can be generalised to include timing properties for the inputs by means of the Laplace transform. The consequent advantages are exemplified in different production models, treating, for instance, capacity requirements and safety stock problems. The main literature in this field concerns assembly systems, but the approach is easily applicable to process industries with a divergent material flow or when feedback is essential.
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| 5. |
- Grubbström, Robert W., 1941-, et al.
(författare)
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Modelling Rescheduling Activities in a Multi-Period Production-Inventory System
- 2000
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Ingår i: International Journal of Production Economics. - : Elsevier. - 0925-5273 .- 1873-7579. ; 68:2, s. 123-135
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Tidskriftsartikel (refereegranskat)abstract
- Decisions for planning production activities for multi-period production–inventory systems have been studied in a number of papers applying input–output analysis and the Laplace transform. The decisions have concerned activities spread out over time without having the opportunity to adjust future decisions when the external and/or internal circumstances change. In this paper, we extend the analysis to situations when rescheduling is possible. Firstly, different classes of causes justifying rescheduling activities are presented including periodic rescheduling and “net change”. Secondly, in terms of previously developed theory, we model the behaviour of a simple single-level production–inventory system for which its production plan may be modified at one point in the future.
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| 6. |
- Kim, H. U., et al.
(författare)
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New pollen-specific receptor kinases identified in tomato, maize and Arabidopsis : the tomato kinases show overlapping but distinct localization patterns on pollen tubes
- 2002
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Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 50:1, s. 1-16
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Tidskriftsartikel (refereegranskat)abstract
- We previously characterized LePRK1 and LePRK2, pollen-specific receptor kinases from tomato (Muschietti et al., 1998). Here we identify a similar receptor kinase from maize, ZmPRK1, that is also specifically expressed late in pollen development, and a third pollen receptor kinase from tomato, LePRK3. LePRK3 is less similar to LePRK1 and LePRK2 than either is to each other. We used immunolocalization to show that all three LePRKs localize to the pollen tube wall, in partially overlapping but distinct patterns. We used RT-PCR and degenerate primers to clone homologues of the tomato kinases from other Solanaceae. We deduced features diagnostic of pollen receptor kinases and used these criteria to identify family members in the Arabidopsis database. RT-PCR confirmed pollen expression for five of these Arabidopsis candidates; two of these are clearly homologues of LePRK3. Our results reveal the existence of a distinct pollen-specific receptor kinase gene family whose members are likely to be involved in perceiving extracellular cues during pollen tube growth.
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| 7. |
- Kozaki, Koichi, et al.
(författare)
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Blockade of platelet-derived growth factor or its receptors transiently delays but does not prevent fibrous cap formation in ApoE null mice.
- 2002
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Ingår i: The American journal of pathology. - 0002-9440. ; 161:4, s. 1395-407
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Tidskriftsartikel (refereegranskat)abstract
- Platelet-derived growth factor (PDGF) is a potent stimulant of smooth muscle cell migration and proliferation in culture. To test the role of PDGF in the accumulation of smooth muscle cells in vivo, we evaluated ApoE -/- mice that develop complex lesions of atherosclerosis. Fetal liver cells from PDGF-B-deficient embryos were used to replace the circulating cells of lethally irradiated ApoE -/- mice. One month after transplant, all monocytes in PDGF-B -/- chimeras are of donor origin (lack PDGF), and no PDGF-BB is detected in circulating platelets, primary sources of PDGF in lesions. Although lesion volumes are comparable in the PDGF-B +/+ and -/- chimeras at 35 weeks, lesions in PDGF-B -/- chimeras contain mostly macrophages, appear less mature, and have a reduced frequency of fibrous cap formation as compared with PDGF-B +/+ chimeras. However, after 45 weeks, smooth muscle cell accumulation in fibrous caps is indistinguishable in the two groups. Comparison of elicited peritoneal macrophages by RNase protection assay shows an altered cytokine and cytokine receptor profile in PDGF-B -/- chimeras. ApoE -/- mice were also treated for up to 50 weeks with a PDGF receptor antagonist that blocks all three PDGF receptor dimers. Blockade of the PDGF receptors similarly delays, but does not prevent, accumulation of smooth muscle and fibrous cap formation. Thus, elimination of PDGF-B from circulating cells or blockade of PDGF receptors does not appear sufficient to prevent smooth muscle accumulation in advanced lesions of atherosclerosis.
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| 9. |
- Lu, W, et al.
(författare)
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Enhancement of room-temperature photoluminescence in InAs quantum dots
- 2003
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Ingår i: Applied Physics Letters. - : American Institute of Physics. - 0003-6951 .- 1077-3118. ; 83:21, s. 4300-4302
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Tidskriftsartikel (refereegranskat)abstract
- We report pronounced enhancement of room-temperature photoluminescence up to 80-fold induced by proton implantation and the rapid thermal annealing process in a multilayer InAs/GaAs quantum-dot structure. This effect is studied by a combination of material methods and resulted from both proton passivation and carrier capture enhancement effects. The maximum photoluminescence peak shift is about 23 meV, resulting from the intermixing of quantum dots. Linear dependence behavior as observed for both the nonradiative recombination time and carrier relaxation time on the ion-implantation dose. Maximum enhancement of the photoluminescence is observed for a proton implantation dose of 1.0x10(14) cm(-2) followed by rapid thermal annealing at 700 degreesC. These effects will be useful for quantum dot optoelectronic devices.
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| 10. |
- Mason, M.G., et al.
(författare)
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Interfacial chemistry of Alq3 and LiF with reactive metals
- 2001
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 89:5, s. 2756-2765
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure and chemistry of interfaces between tris-(8-hydroxyquinoline) aluminum (Alq3) and representative group IA and IIA metals, Al, and Al/LiF have been studied by x-ray and ultraviolet photoelectron spectroscopies. Quantum-chemical calculations at the density functional theory level predict that the Alq3 radical anion is formed upon reaction with the alkali metals. In this case, up to three metal atoms can react with a given Alq3 molecule to form the trivalent anion. The anion formation results in a splitting of the N 1 s core level and formation of a new feature in the previously forbidden energy gap. Virtually identical spectra are observed in the Al/LiF/Alq3 system, leading to the conclusion that the radical anion is also formed when all three of these constituents are present. This is support by a simple thermodynamic model based on bulk heats of formation. In the absence of LiF or similar material, the reaction of Al with Alq3 appears to be destructive, with the deposited Al reacting directly with the quinolate oxygen. We proposed that in those circumstances where the radical anion is formed, it and not the cathode metal are responsible for the electron injection properties. This is borne out by producing excellent injecting contacts when Ag and Au are used as the metallic component of the cathode structure. © 2001 American Institute of Physics.
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