| 1. |
- Schael, S, et al.
(author)
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Precision electroweak measurements on the Z resonance
- 2006
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In: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Research review (peer-reviewed)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 2. |
- Chen, Fengxiang, et al.
(author)
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Adaptive chaos synchronization based on LMI technique
- 2007
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In: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 75:3, s. 285-288
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Journal article (peer-reviewed)abstract
- The paper investigates the robust synchronization for two identical uncertain chaotic systems with different parameters perturbation and external disturbances. Based on Lyapunov stability theory, linear matrix inequality (LMI) techniques and adaptive techniques, a novel controller is proposed. With the resulting controller, global asymptotical synchronization between two identical uncertain chaotic systems is achieved. Finally, a Lorenz system is given as an example to verify the effectiveness of the proposed controller.
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| 3. |
- Chen, Fengxiang, et al.
(author)
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Robust control of chaos in the Lorenz system with the variable structure control approach
- 2008
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In: Physica scripta. T. - : IOP Publishing. - 0281-1847 .- 0031-8949 .- 1402-4896. ; 77:2
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Journal article (other academic/artistic)abstract
- This paper is concerned with the robust control for a class of the uncertain Lorenz system subject to sector nonlinear input. Based on rigorous mathematical analysis, the proposed variable structure controller can drive the system state exactly to a class of a specific point or in the predictable neighborhood of an arbitrary desired point in the state space even with mismatch uncertainties. Moreover, the controller ensures that one of the error components can approach zero as time approaches infinity. Finally, numerical simulation results show the effectiveness of our work.
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| 4. |
- Chen, Fengxiang, et al.
(author)
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Stabilization of parameters perturbation chaotic system via adaptive backstepping technique
- 2008
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In: Applied Mathematics and Computation. - : Elsevier BV. - 0096-3003 .- 1873-5649. ; 200:1, s. 101-109
-
Journal article (peer-reviewed)abstract
- The work of Yassen [M.T. Yassen, Chaos control of chaotic dynamical systems using backstepping design, Chaos Soliton Fract. 27 (2006) 537-548] which mainly investigated the stabilization problem for a class of chaotic systems without the parameters perturbation. This paper is concerned with stabilization problem for a class of parameters perturbation chaotic systems via both backstepping design method and adaptive technique. The proposed controllers can guarantee that the parameters perturbation systems will be stabilized at a fixed bounded point. Furthermore, the paper also proposes controllers to stabilize the uncertain chaotic system at equilibrium point with only backstepping design method. Finally, numerical simulations are given to illustrate the effectiveness of the proposed controllers
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| 5. |
- Du, CW, et al.
(author)
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Arsenic trioxide reduces the invasive and metastatic properties of nasopharyngeal carcinoma cells in vitro
- 2006
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In: Brazilian journal of medical and biological research. - 0100-879X .- 1414-431X. ; 39:5, s. 677-685
-
Journal article (peer-reviewed)abstract
- Nasopharyngeal carcinoma (NPC) is notorious for the metastases, which are in close association with Epstein-Barr virus-encoded latent membrane protein 1 (LMP1). Arsenic trioxide (As2O3) has been shown to induce apoptosis and differentiation in NPC xenografts. Then, can it repress the cancer cells' metastasis potential? To elucidate this issue, the present study was performed. LMP1-negative cell line HNE1 and LMP1-positive cell line HNE1-LMP1 were used as in vitro model. Cells (1 × 105/mL) were cultured with or without 3 μM As2O3 for 48 h. Then the survival cells were collected to investigate their potential of colony formation, attachment, invasion, and migration. Both confocal immunofluorescence staining and Western blot were used to detect the changes of LMP1 expression. The changes of MMP-9 were examined by RT-PCR assay and Western blot. The results were as follow: i) the colony formation inhibition rate (75.41 ± 3.9% in HNE1-LMP1 cells vs 37.89 ± 4.9% in HNE1 cells), the rate of attachment (HNE1-LMP1 vs HNE1: 56.40 ± 3.5 vs 65.87 ± 5.9%), the invasion inhibitory rate (HNE1-LMP1 vs HNE1: 56.50 ± 3.7 and 27.91 ± 2.1%), and the migration inhibitory rate (HNE1-LMP1 vs HNE1: 48.70 ± 3.9 vs 29.19 ± 6.27%) were all significantly different between the two cell lines (P < 0.01). ii) LMP1 was down-regulated in As2O3-treated HNE1-LMP1 cells. iii) The reduction of MMP-9 was found in As2O3-treated groups, more evident in HNE1-LMP1 cells. Thus, we conclude that As2O3 can reduce metastasis potential of NPC cells, involving inhibition of MMP-9 expression. LMP1 were also reduced in this process and seemed to enhance anti-metastasis activity of As2O3. © 2006 Brazilian Journal of Medical and Biological Research.
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| 6. |
- Elsik, Christine G., et al.
(author)
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The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
- 2009
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
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Journal article (peer-reviewed)abstract
- To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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| 7. |
- Lin, Chen, et al.
(author)
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Concomitant use of Ad5/35 chimeric oncolytic adenovirus with TRAIL gene and taxol produces synergistic cytotoxicity in gastric cancer cells
- 2009
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In: Cancer Letters. - : Elsevier BV. - 1872-7980 .- 0304-3835. ; 284:2, s. 141-148
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Journal article (peer-reviewed)abstract
- Chimeric adenoviral vectors possessing fiber derived from human adenovirus subgroup B (Ad35) have been developed for their high infection efficiency in cell types which are refractory to adenovirus serotype 5 (Subgroup C) The present study constructed an E1B-deleted chimeric oncolytic adenovirus, SG235-TRAIL, which carries a human TRAIL gene expression cassette and whose fiber shaft and knob domains are from serotype AM. It was found that SG235-TRAIL preferentially replicated in gastric cancer cell lines, SGC-7901 and BGC-823 compared to in normal human fibroblast BJ cells. Also, when compared with a replication-deficient chimeric vector Ad5/35-TRAIL, SG235-TRAIL mediated a higher level of the transgene expression via viral replication in the cancer cells. Further, because of the more efficient cell-entry and infection, SG235-TRAIL induced stronger cell apoptosis than the Ad5 CRAD vector, ZD55-TRAIL In addition, SG235-TRAIL in combination with the chemotherapeutic drug, taxol, produced a synergistic cytotoxic effect in cancer cells in vitro without causing significant toxicity to normal cells. In the gastric tumor xenograft mouse model, intratumoral SG235-TRAIL injection produced a significant antitumor effect 14 days after treatment. Pathological examination demonstrated TRAIL expression and associated apoptosis in majority of SG235-TRAIL-treated tumor cells. These results suggest that SG235-TRAIL is a potential novel, efficient anti-cancer agent, and in combination with taxol, it would be even more useful with considerably low toxic side effects. (C) 2009 Elsevier Ireland Ltd. All rights reserved.
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| 8. |
- Amsler, C., et al.
(author)
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Review of particle physics
- 2008
-
In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 667:1-5, s. 1-1
-
Research review (peer-reviewed)abstract
- This biennial Review summarizes much of particle physics. Using data from previous editions., plus 2778 new measurements from 645 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors., probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on CKM quark-mixing matrix, V-ud & V-us, V-cb & V-ub, top quark, muon anomalous magnetic moment, extra dimensions, particle detectors, cosmic background radiation, dark matter, cosmological parameters, and big bang cosmology.
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| 9. |
- Armesto, N., et al.
(author)
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Heavy-ion collisions at the LHC-Last call for predictions
- 2008
-
In: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 35:5, s. 054001-
-
Research review (peer-reviewed)abstract
- This writeup is a compilation of the predictions for the forthcoming Heavy Ion Program at the Large Hadron Collider, as presented at the CERN Theory Institute 'Heavy Ion Collisions at the LHC - Last Call for Predictions', held from 14th May to 10th June 2007.
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| 10. |
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| 11. |
- Chen, Chun Lin, et al.
(author)
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In situ TEM observation of decomposition of high-purity sapphire
- 2009
-
In: Philosophical Magazine Letters. - : Informa UK Limited. - 0950-0839 .- 1362-3036. ; 89:2, s. 113-119
-
Journal article (peer-reviewed)abstract
- The decomposition of agr-Al2O3 under 200 keV electron irradiation has been investigated by in situ high-resolution electron microscopy (HREM). It was confirmed that aluminium precipitated from agr-Al2O3 under 200 keV electron irradiation for less than 1 min over the temperature range from 700 to 1273 K. The electron dose rate was of the order of 1023 e m-2 s-1 and the vacuum level of the microscope was better than 10-6 Pa. The mechanisms of agr-Al2O3 decomposition were discussed based on two possible decomposition models: the thermally activated atom movement and the forced atom displacement
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| 12. |
- Chien, Ming-Hsien, et al.
(author)
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Vascular endothelial growth factor-C (VEGF-C) promotes angiogenesis by induction of COX-2 in leukemic cells via the VEGF-R3/JNK/AP-1 pathway.
- 2009
-
In: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 30:12, s. 2005-13
-
Journal article (peer-reviewed)abstract
- Vascular endothelial growth factor (VEGF)-C is recognized as a tumor lymphangiogenic factor based on the effects of activated VEGF-R3 on lymphatic endothelial cells. Many tumor cells express VEGF-R3 but the function of this receptor in tumor cells is largely unknown. It has been reported that the VEGF-C/VEGF-R3 axis is activated in subsets of leukemia patients. Herein, we have shown that VEGF-C induces angiogenic activity in the tube formation assay invitro and Matrigel plug assay in vivo by upregulating an angiogenic factor, cyclooxygenase-2 (COX-2), through VEGF-R3 in the human acute myeloid leukemia (AML) cell line, THP-1. COX-2 induction by VEGF-C was also observed in other VEGF-R3(+) human AML cell lines (U937 and HL60). Moreover, immunohistochemical analysis of bone marrow specimens of 37 patients diagnosed with AML revealed that VEGF-C expression in specimens was associated with the expression of COX-2 (P < 0.001). The manner by which signaling pathways transduced by VEGF-C is responsible for COX-2 upregulation was further investigated. Blocking the p42/44 mitogen-activated protein kinase (MAPK) pathway with the MAPK kinase inhibitor, PD 98059, failed to inhibit VEGF-C-mediated COX-2 expression. However, VEGF-C-induced COX-2 upregulation was effectively abolished by overexpression of dominant-negative c-Jun N-terminal kinase (JNK) or treatment with the JNK inhibitor, SP 600125. VEGF-C induced JNK-dependent nuclear translocation of c-Jun. Furthermore, chromatin immunoprecipitation and reporter assays revealed that VEGF-C enhanced c-Jun binding to the cyclic adenosine 3',5'-monophosphate-response element of the COX-2 promoter and induced COX-2 expression. In sum, the data herein highlight the pathogenic role of VEGF-C in leukemia via regulation of angiogenesis through upregulation of COX-2.
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| 13. |
- Ding, Li, et al.
(author)
-
Somatic mutations affect key pathways in lung adenocarcinoma
- 2008
-
In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 455:7216, s. 1069-1075
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Journal article (peer-reviewed)abstract
- Determining the genetic basis of cancer requires comprehensive analyses of large collections of histopathologically well-classified primary tumours. Here we report the results of a collaborative study to discover somatic mutations in 188 human lung adenocarcinomas. DNA sequencing of 623 genes with known or potential relationships to cancer revealed more than 1,000 somatic mutations across the samples. Our analysis identified 26 genes that are mutated at significantly high frequencies and thus are probably involved in carcinogenesis. The frequently mutated genes include tyrosine kinases, among them the EGFR homologue ERBB4; multiple ephrin receptor genes, notably EPHA3; vascular endothelial growth factor receptor KDR; and NTRK genes. These data provide evidence of somatic mutations in primary lung adenocarcinoma for several tumour suppressor genes involved in other cancers--including NF1, APC, RB1 and ATM--and for sequence changes in PTPRD as well as the frequently deleted gene LRP1B. The observed mutational profiles correlate with clinical features, smoking status and DNA repair defects. These results are reinforced by data integration including single nucleotide polymorphism array and gene expression array. Our findings shed further light on several important signalling pathways involved in lung adenocarcinoma, and suggest new molecular targets for treatment.
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| 14. |
- Fu, J., et al.
(author)
-
Trends in graded precipitation in China from 1961 to 2000
- 2008
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In: Advances in atmospheric Sciences. - : Springer Science and Business Media LLC. - 1861-9533 .- 0256-1530. ; 25:2, s. 267-278
-
Journal article (peer-reviewed)abstract
- Daily precipitation rates observed at 576 stations in China from 1961 to 2000 were classified into six grades of intensity, including trace (no amount), slight (<= 1 mm d(-1)), small, large, heavy, and very heavy. The last four grades together constitute the so called effective precipitation (> 1 mm d(-)1). The spatial distribution and temporal trend of the graded precipitation days are examined. A decreasing trend in trace precipitation days is observed for the whole of China, except at several sites in the south of the middle section of the Yangtze River, while a decreasing trend in slight precipitation days only appears in eastern China. The decreasing trend and interannual variability of trace precipitation days is consistent with the warming trend and corresponding temperature variability in China for the same period, indicating a possible role played by increased surface air temperature in cloud formation processes. For the effective precipitation days, a decreasing trend is observed along the Yellow River valley and for the middle reaches of the Yangtze River and Southwest China, while an increasing trend is found for Xinjiang, the eastern Tibetan Plateau, Northeast China and Southeast China. The decreasing trend of effective precipitation days for the middle-lower Yellow River valley and the increasing trend for the lower Yangtze River valley are most likely linked to anomalous monsoon circulation in East China. The most important contributor to the trend in effective precipitation depends upon the region concerned.
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| 15. |
- Fu, Ying, et al.
(author)
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Design of semiconductor CdSe core ZnS/CdS multishell quantum dots for multiphoton applications
- 2007
-
In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 90:17, s. 173102-1-173102-3
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Journal article (peer-reviewed)abstract
- Optical properties of colloidal II-VI semiconductor CdSe cores with ZnS and CdS multishell quantum dots (QDs) have been studied by experimental characterization and theoretical analysis. Due to the large number of energy states densely compacted in both conduction and valence bands of the quantum dots, strong interband and intraband optical couplings are induced by the multiphoton excitation, implicating an efficient fluorescence of such II-VI-based core-multishell CdSe QDs. This fact in combination with the advantage of the size tolerance of II-VI QDs with respect to the narrow fluorescence bandwidth make these systems excellent candidates for applications using fluorescence induced by multiphoton excitation.
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| 16. |
- Gao, S-W, et al.
(author)
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Enhanced NEH method in solving permutation flow shop problem
- 2007
-
In: Shanghai Jiaotong University. Journal. - 1007-1172. ; 12E:1, s. 47-52
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Journal article (peer-reviewed)abstract
- This paper proposed an enhanced NEH with full insertion moves to solve the permutation flow shop problem. The characteristics of the original NEH are investigated and analyzed, and it is concluded that the given method would be promising to find better solutions, while the cost would be increased. Fast makespan calculating method and eliminating non-promising permutation policy are introduced to reduce the evaluation effort. The former decreases the time complexity from O(n4m) to O(n3m), which is an acceptable cost for medium and small size instances considering the obtained solution quality. The results from computational experience show that the latter also can eliminate a lot of non-promising solutions.
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| 17. |
- Garcia-Closas, Montserrat, et al.
(author)
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Heterogeneity of breast cancer associations with five susceptibility loci by clinical and pathological characteristics
- 2008
-
In: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 4:4, s. e1000054-
-
Journal article (peer-reviewed)abstract
- A three-stage genome-wide association study recently identified single nucleotide polymorphisms (SNPs) in five loci (fibroblast growth receptor 2 (FGFR2), trinucleotide repeat containing 9 (TNRC9), mitogen-activated protein kinase 3 K1 (MAP3K1), 8q24, and lymphocyte-specific protein 1 (LSP1)) associated with breast cancer risk. We investigated whether the associations between these SNPs and breast cancer risk varied by clinically important tumor characteristics in up to 23,039 invasive breast cancer cases and 26,273 controls from 20 studies. We also evaluated their influence on overall survival in 13,527 cases from 13 studies. All participants were of European or Asian origin. rs2981582 in FGFR2 was more strongly related to ER-positive (per-allele OR (95%CI) = 1.31 (1.27-1.36)) than ER-negative (1.08 (1.03-1.14)) disease (P for heterogeneity = 10(-13)). This SNP was also more strongly related to PR-positive, low grade and node positive tumors (P = 10(-5), 10(-8), 0.013, respectively). The association for rs13281615 in 8q24 was stronger for ER-positive, PR-positive, and low grade tumors (P = 0.001, 0.011 and 10(-4), respectively). The differences in the associations between SNPs in FGFR2 and 8q24 and risk by ER and grade remained significant after permutation adjustment for multiple comparisons and after adjustment for other tumor characteristics. Three SNPs (rs2981582, rs3803662, and rs889312) showed weak but significant associations with ER-negative disease, the strongest association being for rs3803662 in TNRC9 (1.14 (1.09-1.21)). rs13281615 in 8q24 was associated with an improvement in survival after diagnosis (per-allele HR = 0.90 (0.83-0.97). The association was attenuated and non-significant after adjusting for known prognostic factors. Our findings show that common genetic variants influence the pathological subtype of breast cancer and provide further support for the hypothesis that ER-positive and ER-negative disease are biologically distinct. Understanding the etiologic heterogeneity of breast cancer may ultimately result in improvements in prevention, early detection, and treatment.
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| 18. |
- Haeger-Eugensson, Marie, et al.
(author)
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Spridning av föroreningar till luft från bränder
- 2008
-
Reports (other academic/artistic)abstract
- Detta projekt är en del av en större studie med övergripande syftet att ta fram en metod för beräkning av emissioner från bränder samt användande av dessa till spridningsberäkningar både till luft och vatten. Resultat från luftemissionsdelen har använts som indata till de beräkningar genomförda i detta delprojekt vars syfte varit att testa hur dispersion och haltnivåer kan skilja sig beroende på val av modell, definiera styrande brand- och meteorologiska parametrarna, för deposition och halt i luft och att utveckla och testa en metod för generaliserade spridningsberäknigar för bränder genom statistiskt bearbetade resultat från ett års beräkningar för olika meteorologiska klasser. Det har hittills varit svårt att spridningsberäkna bränder med avancerade spridningsmodeller eftersom nödvändiga indata inte funnits. Fokus har istället legat på att återge brandförloppet bra medan meteorologi, och därmed dispersionen, varit förenklad. Vi har inte funnit utred-ningar som visar om enklare modeller eller generaliseringar av befintliga brandmodeller utgör ett tillräckligt bra underlag för snabb bedömning av miljö- och hälsoeffekter från bränder. Beräkningarna i detta projekt är genomförda med TAPM-modellen under olika årstider som medel- och maximala dygnsvärden samt av dygnsdeposition av PM10 för respektive plymriktning. Medelvärdena används för bedömning av miljöpåverkan och maximala dygnshalter för mer akuta hälsoeffekter för att utforma och förebyggande åtgärder, både akut och långsiktigt (t.ex. stadsplanering). Förhållandet mellan max- och medelhalter varierar beroende på säsong och spridningsförutsättningar, med maxhalten ca 50 ggr högre och med stor variation. Haltnivåerna i centrum- respektive kransplymerna är båda ca 200 µg/m3 även om emissionen är ca 5 ggr högre i cen-trumplymen jämfört med de sammanlagda emissionerna från kransplymerna. Skälet är att den högre centrumplymen sprids mer effektivt till följd av den dubbelt så höga vindhastigheten på hög nivå. Validering av beräknade haltnivåer och plymlyft har visat att med brandindata från en brandmodell har spridningen av PM10 återgets väl med TAPM -modellen. Beräkningarna är även tänkta att vara bas för utveckling av en modell anpassad för användande under fältmässiga förhållanden för att snabbt få fram beslutsunderlag för åtgärder vid olyckor (som evakuering) och därmed förebygga och minimera skador på t.ex. miljön och människors hälsa.
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| 19. |
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| 20. |
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| 21. |
- Hou, Yuanyuan, et al.
(author)
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Comparative study of pressure-induced polymerization of C60 nanorods and single crystals
- 2007
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In: Journal of Physics Condensed Matter. - Bristol : Institute of Physics. - 0953-8984 .- 1361-648X. ; 19:42, s. 425207-
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Journal article (peer-reviewed)abstract
- In this paper, we report a comparative study of pressure-induced polymerization in C60 nanorods and bulk single crystals, treated simultaneously under various pressures and temperatures in the same experiment. For both materials, orthorhombic, tetragonal and rhombohedral phases have been produced under high pressure and high temperature. The structures have been identified and compared between the two sample types by Raman and photoluminescence spectroscopy. There are differences between the Raman and photoluminescence spectra from the two types of materials for all polymeric phases, but especially for the tetragonal phase. From the comparison between nanorods and bulk samples, we tentatively assign photoluminescence peaks for various polymeric phases.
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| 22. |
- Hou, Yuanyuan, et al.
(author)
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Photoluminescence properties of high-pressure-polymerized C60 nanorods in the orthorhombic and tetragonal phases.
- 2006
-
In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89:18, s. 181925-
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Journal article (peer-reviewed)abstract
- C60nanorods in two polymeric phases have been synthesized under differenthigh pressure and high temperature conditions. Orthorhombic and tetragonal phaseshave been identified from Raman spectra. The rod shape canbe kept under quasihydrostatic pressure. The photoluminescence intensity of thepolymeric C60 nanorods has been greatly enhanced compared with thatof pristine C60 nanorods. The main fluorescence band shifted from730 nm in the unpolymeric phase to 748 nm and near infrared780 nm in the orthorhombic and tetragonal phases, respectively. The enhancedphotoluminescence with tunable frequency for different polymeric C60 nanorods suggestspotential applications in luminescent nanomaterials.
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| 23. |
- Hou, Yuanyuan, et al.
(author)
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Pressure-induced polymerization of nano- and submicrometer C60 rods into a rhombohedral phase
- 2006
-
In: Chemical Physics Letters. - : Elsevier BV. - 0009-2614. ; 423:1-3, s. 215-219
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Journal article (peer-reviewed)abstract
- C-60 rods with nano- and submicrometer dimensions were polymerized at 4.5 GPa and 973 K. Raman spectroscopy showed that the material transformed into a rhombohedral polymeric structure under high pressure and high temperature (HPHT) conditions. The HPHT polymerized samples keep the original rod shape. The position dependence of photoluminescence (PL) spectra have been studied on the rhombohedral polymer C60 rods at room temperature. The intensity of the 1.74 eV peak from the rhombohedral phase varies systematically between the edge of and the middle of the rod. Our results indicate that the 1.74 eV peak originates from surface defects.
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| 24. |
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| 25. |
- Karlsson, Per Erik, 1957, et al.
(author)
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Increasing risk for negative ozone impacts on vegetation in northern Sweden
- 2007
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In: Environmental Pollution. ; 150, s. 96-106
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Journal article (peer-reviewed)abstract
- Trends were found for increasing surface ozone concentrations during AprileSeptember in northern Sweden over the period 1990e2006 as well as for an earlier onset of vegetation growing season. The highest ozone concentrations in northern Sweden occurred in April and the ozone concentrations in April showed a strong increasing trend. A model simulation of ozone flux for Norway spruce indicated that the provisional ozone flux based critical level for forests in Europe is exceeded in northern Sweden. Future climate change would have counteracting effects on the stomatal conductance and needle ozone uptake, mediated on the one hand by direct effect of increasing air temperatures and on the other through increasing water vapour pressure difference between the needles and air. Thus, there is a substantial and increasing risk for negative impacts of ozone on vegetation in northern Sweden, related mainly to increasing ozone concentrations and an earlier onset of the growing season.
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