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- Andersson, Patrik, 1974, et al.
(author)
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Framtidsbilder för samhällsbyggnad
- 2006
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Reports (other academic/artistic)abstract
- Framtidsbilder för samhällsbyggnad 2020De kommande 15 åren står institutionen för Bygg- och miljöteknik inför stora förändringar. Därför har institutionen initierat projektet Framtidsbilder 2020 där man engagerat en framtidspanel bestående av elva yngre disputerade forskare. Arbetet inleddes med ett breddgruppsmöte där 110 personer representerande institutionens personal och studenter deltog. Vid mötet identifierades ett antal trender och osäkra utvecklingar som påverkar framtiden inom samhällsbyggnadsområdet. Deltagarna bidrog också med idéer till en önskvärd utveckling, vilket har sammanställts och utgör grunden till en gemensam önskvärd framtid/vision för institutionen. Materialet från breddgruppsmötet har bearbetats av Framtidspanelen och resulterat i fyra scenarier som beskriver hur samhällsbyggnadsområdet kan se ut år 2020. Syftet med framtidsbilderna är att de ska vara vägledande för institutionens beslut och förhållningssätt under de kommande åren.Fyra scenarierTurning TorsoSamhället präglas av en ekonomi som är på uppgång, och av ett nytänkande och öppet samhälle. Materiell status och individualism är viktigt. Detta leder till en hög arbetsbelastning samt krav på exklusiva varor av hög kvali-tet. Det finns en stor medvetenhet om miljöpåverkan och klimatförändringar och lösningarna för att klara energiförsörjningen är innovativa.Eco-metropolenDet sveper en grön våg genom dagens samhälle. Under de senaste 15 åren har vi insett att jorden skall vara en bebolig plats även åt dem som kommer efter oss. Vi söker ständigt efter nya, mer förfinade metoder att tillvarata de resurser vi har. Samhället och individen är i balans. Ekonomin är god och vi är miljömedvetna, trygga och integrerade. Nytänkande premieras och icke- materialistiska värderingar står högt i kurs. Vi tänker individuellt, men agerar mer än gärna för kollektivets bästa. Utbildning är gratis TrädgårdsstadenEtt samhälle där vi lärt oss hantera stress, men känner oss otrygga och helst umgås i slutna sociala sammanhang. Vi bor enkelt inne i stan, eller gärna på landsbygden nära storstäderna. Minskade behov av högutbildade i samhället gör att vi har svårt att rekrytera studenter till teknikutbildningar. Det traditionella tankesättet leder till kulturkrockar med företag och personer från andra länder.Gated communitiesFörsämrad ekonomi och ökad egoism har lett fram till ett stressat, otryggt och segregerat samhälle. Accelererande klimatförändringar och ökad miljö-påverkan skrämmer oss, men trots det åtgärdar vi inte problemen, utan koncentrerar oss på konsekvenserna. Arbetslöshet i samhällsbyggnadssek-torn leder till sänkt status för samhällsbyggaren. Vi har därför svårt att rekrytera studenter, och även forskningen har låg status.
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| 2. |
- Andersson, Pontus, 1971, et al.
(author)
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Isobar Selective Laser Photodetachment In Trace Element Analysis
- 2009
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In: AIP Conference Proceedings. ; 1104
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Conference paper (peer-reviewed)abstract
- We are investigating the possibility to use laser photodetachment of negative ions as an isobaric selective filter in accelerator mass spectrometry (AMS). If successful, this method can be used to obtain higher sensitivity realized through better selectivity by suppression of molecular and/or elemental isobaric interference in different investigations using ultra rare isotopes in the 10−13 range and below.
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| 3. |
- Andersson, Pontus, 1971
(author)
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Laser Photodetachment of Negative Ions - Fundamental Research and Applications
- 2009
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Doctoral thesis (other academic/artistic)abstract
- Photodetachment studies of atomic and molecular negative ions in the gas phase are presented. Negative ions are loosely bound quantum systems whose existence is strongly dependent on the correlations between the electrons. This makes sophisticated calculations of the structure and dynamics for these systems complex and experimental data are needed for verification. Negative ions are also important in applications such as plasma etching and atmospheric studies. One of the most important applications for negative ions is as the state of matter for injection in tandem accelerators used in Accelerator Mass Spectrometry (AMS), the most sensitive method for ultra trace isotope analysis. Using negative ions in the injection stage provides isobar suppression in cases where the contaminating isobar does not form stable negative ions. Several experiments on laser interaction with a beam of mass-selected negative ions are presented. The objective for these studies can be divided into three subgroups: structure studies, dynamic studies, and proof-of-principle experiments for applications of negative ions. In the first group, the value for the electron affinity and the fine structure splitting of phosphorus is refined. The value of the electron affinity of tungsten is improved and the origin of the photodetachment signal below threshold is discussed. Resonant structure in the cross section and the electron affinity of cerium is treated. Finally, a predicted excited state in platinum is observed experimentally for the first time. The second group consists of the lifetime measurements of metastable excited states for tellurium, selenium and silicon. These measurements were made at the magnetic heavy ion storage ring CRYRING at Manne Siegbahn Laboratories in Stockholm. The third and last group are proof-of-principle experiments of isobar and neighboring isotope suppression by laser interaction. Suppression of up to four orders of magnitude is reached and the implementation into mass spectrometric systems are discussed.
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| 4. |
- Andersson, Pontus, 1971, et al.
(author)
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Nearly complete isobar suppression by photodetachment
- 2010
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In: Journal of Applied Physics. - : AIP Publishing. - 1089-7550 .- 0021-8979. ; 107:2
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Journal article (peer-reviewed)abstract
- The efficiency of selective suppression of negative ions by photodetachment in a gas-filled radio frequency quadrupole ion cooler was investigated with a new detection method. A neodymium doped yttrium aluminum garnet laser beam at 1064 nm was used to remove Co− ions in the radio frequency quadrupole cooler and the remaining ions were then probed by photodetachment and neutral particle detection. More than 99.99% suppression of the Co− ions was observed. Under identical conditions, only 20% of a Ni− beam was suppressed. The results demonstrate that this isobar suppression technique can lead to nearly complete elimination of certain isobaric contaminants in negative ion beams, opening up new experimental possibilities in nuclear and atomic research and accelerator mass spectrometry.
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| 5. |
- Andersson, Pontus, 1971, et al.
(author)
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Observation of the 2S1/2 metastable state in Pt−
- 2009
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In: PHYSICAL REVIEW A. - 1050-2947. ; 79, s. 022502 -
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Journal article (peer-reviewed)abstract
- We have experimentally investigated the structure of the Pt− ion using laser photodetachment threshold spectroscopy. The experiment was conducted using a collinear laser-ion beam apparatus, in which the residual atoms created in the photodetachment process were detected. A p-wave threshold was observed in the photo- detachment spectrum at an energy of 6851͑13͒ cm−1. We conclude that this onset originates from a photode- tachment transition in which the initial state of Pt− is the previously unobserved 5d106s 2S1/2 state and the final state of Pt is the 5d96s 3D3 ground state. The excitation energy of the 2S1/2 state is determined to be 10 289͑13͒ cm−1. This value can be compared with a multiconfiguration Dirac-Fock calculation performed by Thøgersen et al. ͓Phys. Rev. Lett. 76, 2870 ͑1996͔͒, which yielded an excitation energy of 11 301 cm−1. Our data show no indication of the presence of any other state of Pt−. We conclude that the structure of the Pt− ion is now fully known.
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| 6. |
- Andersson, Pontus, 1971, et al.
(author)
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Radiative lifetimes of metastable states of negative ions
- 2006
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In: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622 .- 2469-9926 .- 2469-9934. ; 73, s. 032705-
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Journal article (peer-reviewed)abstract
- We present a technique for measuring the radiative lifetimes of metastable states of negative ions that involves the use of a heavy-ion storage ring. The method has been applied to investigate the radiative decay of the np(3) P-2(1/2) levels of Te-(n=5) and Se-(n=4) and the 3p(3) D-2 state of Si- for which the J=3/2 and 5/2 levels were unresolved. All of these states are metastable and decay primarily by emission of E2 and M1 radiation. Multi Configuration Dirac-Hartree-Fock calculations of rates for the transitions in Te- and Se- yielded lifetimes of 0.45 s and 4.7 s, respectively. The measured values agree well with these predicted values. In the case of the D-2 state of Si-, however, our measurement was only able to set a lower limit on the lifetime. The upper limit of the lifetime that can be measured with our apparatus is set by how long the ions can be stored in the ring, a limit determined by the rate of collisional detachment. Our lower limit of 1 min for the lifetime of the D-2 state is consistent with both the calculated lifetimes of 162 s for the D-2(3/2) level and 27.3 h for the D-2(5/2) level reported by O'Malley and Beck and 14.5 h and 12.5 h, respectively, from our Breit-Pauli calculations.
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| 7. |
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| 8. |
- Andersson, Pontus, 1971, et al.
(author)
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The electron affinity of phosphorus
- 2007
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In: Journal of Physics B-Atomic Molecular and Optical Physics. ; 40:20, s. 4097-4107
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Journal article (peer-reviewed)
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| 9. |
- Bergemalm, Daniel, 1977-, et al.
(author)
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Markers of systemic inflammation in preclinical ulcerative colitis
- 2019
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In: United European Gastroenterology journal. - : Sage Publications. - 2050-6406 .- 2050-6414. ; 7:8_suppl, s. 111-111
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Journal article (peer-reviewed)abstract
- Introduction: Data on the preclinical stage of ulcerative colitis (UC) are sparse. At diagnosis, UC often shows a modest increase in systemic inflammatory markers like C-reactive protein (CRP). However, a subclinical inflammation with elevated levels of CRP and interleukin-6 (IL6) in serum have been observed several years before diagnosis [1]. First-degree relatives, including healthy twin siblings, also display elevated levels of some inflammatory markers as a consequence of shared genetic and environmental risk factors [2]. It is reasonable to believe that the preclinical inflammation, reflecting early pathogenic mechanisms, ultimately leads to a diagnosis of UC.Aim and Method: We aimed to deeper examine the systemic preclinical inflammation in UC using a comprehensive set of protein markers. Cases with UC were identified at clinical follow-up of a prospectively collected population-based cohort of healthy individuals from northern Sweden. Plasma samples from cases and controls were subjected to proximity extension assay for relative quantification of 92 protein markers of inflammation. Results were validated in an inception cohort of treatment naïve, newly diagnosed patients with UC (n=101) vs. healthy controls (n=50). In addition, to examine the impact of shared genetic and environmental factors, a cohort of healthy mono- and dizygotic twin siblings of twins with UC (n=41) and matched healthy controls (n=37) were explored.Results: Pre-diagnostic plasma samples from 72 cases who later in life developed UC and 140 controls, matched for gender, age, year of health survey and area of residence, were identified (table 1). Six proteins were significantly upregulated (p<0.05) in pre-diagnostic UC compared to matched healthy controls. A receiver-operating curve based prediction model using the six protein markers combined with sex, age, smoking status and time to diagnose was set up for validation. The model discriminated newly diagnosed, treatment naïve UC cases from healthy controls (AUC=0.96; CI 0.93-0.98). An AUC of 0.73 (CI 0.62-0.84) was observed when the model was applied to healthy twin siblings vs. healthy controls and four out of six proteins were upregulated similarly as in the pre-diagnostic samples. The relative levels of the six proteins showed an intermediate upregulation in pre-diagnostic samples and samples from healthy twin siblings compared to samples at diagnosis of UC. Only one protein showed a significant correlation with time to diagnosis in the pre-diagnostic samples. Using pathway analysis, the six protein upregulations pointed towards subclinical inflammation in UC being caused by dysregulation of four immune pathways.Conclusions: This is the first comprehensive characterisation of preclinical systemic inflammation in UC. Inflammatory proteins were upregulated several years prior to diagnosis of UC and to some extent these alterations were also seen in healthy twin siblings of UC patients. Characterisation of the preclinical stage of UC could pave the way for identification of predictive biomarkers and preventive strategies.
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| 10. |
- Bergemalm, Daniel, 1977-, et al.
(author)
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Systemic Inflammation in Preclinical Ulcerative Colitis
- 2021
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In: Gastroenterology. - : AGA Institute. - 0016-5085 .- 1528-0012. ; 161:5, s. 1526-1539.e9
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Journal article (peer-reviewed)abstract
- Background & Aims: Preclinical ulcerative colitis is poorly defined. We aimed to characterize the preclinical systemic inflammation in ulcerative colitis, using a comprehensive set of proteins.Methods: We obtained plasma samples biobanked from individuals who developed ulcerative colitis later in life (n = 72) and matched healthy controls (n = 140) within a population-based screening cohort. We measured 92 proteins related to inflammation using a proximity extension assay. The biologic relevance of these findings was validated in an inception cohort of patients with ulcerative colitis (n = 101) and healthy controls (n = 50). To examine the influence of genetic and environmental factors on these markers, a cohort of healthy twin siblings of patients with ulcerative colitis (n = 41) and matched healthy controls (n = 37) were explored.Results: Six proteins (MMP10, CXCL9, CCL11, SLAMF1, CXCL11 and MCP-1) were up-regulated (P < .05) in preclinical ulcerative colitis compared with controls based on both univariate and multivariable models. Ingenuity Pathway Analyses identified several potential key regulators, including interleukin-1β, tumor necrosis factor, interferon-gamma, oncostatin M, nuclear factor-κB, interleukin-6, and interleukin-4. For validation, we built a multivariable model to predict disease in the inception cohort. The model discriminated treatment-naïve patients with ulcerative colitis from controls with leave-one-out cross-validation (area under the curve = 0.92). Consistently, MMP10, CXCL9, CXCL11, and MCP-1, but not CCL11 and SLAMF1, were significantly up-regulated among the healthy twin siblings, even though their relative abundances seemed higher in incident ulcerative colitis.Conclusions: A set of inflammatory proteins are up-regulated several years before a diagnosis of ulcerative colitis. These proteins were highly predictive of an ulcerative colitis diagnosis, and some seemed to be up-regulated already at exposure to genetic and environmental risk factors.
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