| 1. |
- Bauch, Thilo, 1972, et al.
(författare)
-
High critical temperature superconductor Josephson junctions for quantum circuit applications
- 2009
-
Ingår i: Physica Scripta. ; T137, s. 014006-
-
Konferensbidrag (refereegranskat)abstract
- Recent findings of macroscopic quantum properties in high critical temperature superconductor (HTS) Josephson junctions (JJs) point toward the need to revise the role of zero energy quasi-particles in this novel superconductor. We will discuss the possibility of designing superconducting artificial atoms in a transmon configuration to study the low energy excitation spectra of HTS. We have engineered high quality grain boundary JJs on low dielectric constant substrates. By fabricating submicron junctions, we extract values of capacitance and Josephson critical current densities that satisfy the main transmon design requirements. Moreover, the measured critical current noise power extrapolated at 1 Hz gives a dephasing time of 25 ns, which indicates that the observation of macroscopic quantum coherent effects in HTS JJ is a feasible task.
|
|
| 2. |
- Cedergren, Karin, 1975, et al.
(författare)
-
Biepitaxial YBa2Cu3O7-x 0-pi Josephson junctions
- 2010
-
Ingår i: Superconductor Science and Technology. - : IOP Publishing. - 0953-2048 .- 1361-6668. ; 23:3, s. Article Number: 034027-
-
Tidskriftsartikel (refereegranskat)abstract
- We present measurements performed on YBa2Cu3O7-x '0' and '0-pi' Josephson junctions fabricated using the biepitaxial technique with SrTiO3 as substrate and CeO2 as seed layer. Measurements of the critical current as a function of external magnetic field clearly show complementary behavior of the two kinds of junctions. Our results unambiguously show that the d-wave nature of the order parameter dominates the current transport across the junctions despite the faceting on the microscale along the grain boundary line.
|
|
| 3. |
- Devarakonda, Sravani, et al.
(författare)
-
Low-grade intestinal inflammation two decades after pelvic radiotherapy.
- 2023
-
Ingår i: EBioMedicine. - 2352-3964. ; 94
-
Tidskriftsartikel (refereegranskat)abstract
- Radiotherapy is effective in the treatment of cancer but also causes damage to non-cancerous tissue. Pelvic radiotherapy may produce chronic and debilitating bowel symptoms, yet the underlying pathophysiology is still undefined. Most notably, although pelvic radiotherapy causes an acute intestinal inflammation there is no consensus on whether the late-phase pathophysiology contains an inflammatory component or not. To address this knowledge gap, we examined the potential presence of a chronic inflammation in mucosal biopsies from irradiated pelvic cancer survivors.We biopsied 24 cancer survivors two to 20 years after pelvic radiotherapy, and four non-irradiated controls. Using tandem mass tag (TMT) mass spectrometry and mRNA sequencing (mRNA-seq), we charted proteomic and transcriptomic profiles of the mucosal tissue previously exposed to a high or a low/no dose of radiation. Changes in the immune cell populations were determined with flow cytometry. The integrity of the protective mucus layers were determined by permeability analysis and 16S rRNA bacterial detection.942 proteins were differentially expressed in mucosa previously exposed to a high radiation dose compared to a low radiation dose. The data suggested a chronic low-grade inflammation with neutrophil activity, which was confirmed by mRNA-seq and flow cytometry and further supported by findings of a weakened mucus barrier with bacterial infiltration.Our results challenge the idea that pelvic radiotherapy causes an acute intestinal inflammation that either heals or turns fibrotic without progression to chronic inflammation. This provides a rationale for exploring novel strategies to mitigate chronic bowel symptoms in pelvic cancer survivors.This study was supported by the King Gustav V Jubilee Clinic Cancer Foundation (CB), The Adlerbertska Research Foundation (CB), The Swedish Cancer Society (GS), The Swedish State under the ALF agreement (GS and CB), Mary von Sydow's foundation (MA and VP).
|
|
| 4. |
- Albinsson, Bo, 1963, et al.
(författare)
-
Electron and energy transfer in donor-acceptor systems with conjugated molecular bridges
- 2007
-
Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 9:44, s. 5847-5864
-
Tidskriftsartikel (refereegranskat)abstract
- Electron and energy transfer reactions in covalently connected donor-bridge-acceptor assemblies are strongly dependent, not only on the donor-acceptor distance, but also on the electronic structure of the bridge. In this article we describe some well characterised systems where the bridges are π-conjugated chromophores, and where, specifically, the interplay between bridge length and energy plays an important role for the donor-acceptor electronic coupling. For any application that relies on the transport of electrons, for example molecule based solar cells or molecular scale electronics, it will be imperative to predict the electron transfer capabilities of different molecular structures. The potential difficulties with making such predictions and the lack of suitable models are also discussed. © the Owner Societies.
|
|
| 5. |
|
|
| 6. |
- Eriksson, Charli C-G, 1948-, et al.
(författare)
-
Academic practice-policy partnerships for health promotion research : experiences from three research programs
- 2014
-
Ingår i: Scandinavian Journal of Public Health. - : SAGE Publications. - 1403-4948 .- 1651-1905. ; 42:15 Suppl, s. 88-95
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The development of knowledge for health promotion requires an effective mechanism for collaboration between academics, practitioners, and policymakers. The challenge is better to understand the dynamic and ever-changing context of the researcher-practitioner-policymaker-community relationship.AIMS: The aims were to explore the factors that foster Academic Practice Policy (APP) partnerships, and to systematically and transparently to review three cases.METHODS: Three partnerships were included: Power and Commitment-Alcohol and Drug Prevention by Non-Governmental Organizations in Sweden; Healthy City-Social Inclusion, Urban Governance, and Sustainable Welfare Development; and Empowering Families with Teenagers-Ideals and Reality in Karlskoga and Degerfors. The analysis includes searching for evidence for three hypotheses concerning contextual factors in multi-stakeholder collaboration, and the cumulative effects of partnership synergy.RESULTS: APP partnerships emerge during different phases of research and development. Contextual factors are important; researchers need to be trusted by practitioners and politicians. During planning, it is important to involve the relevant partners. During the implementation phase, time is important. During data collection and capacity building, it is important to have shared objectives for and dialogues about research. Finally, dissemination needs to be integrated into any partnership. The links between process and outcomes in participatory research (PR) can be described by the theory of partnership synergy, which includes consideration of how PR can ensure culturally and logistically appropriate research, enhance recruitment capacity, and generate professional capacity and competence in stakeholder groups. Moreover, there are PR synergies over time.CONCLUSIONS: The fundamentals of a genuine partnership are communication, collaboration, shared visions, and willingness of all stakeholders to learn from one another
|
|
| 7. |
- Hellström, Sara, et al.
(författare)
-
A follow up on the feasibility after national implementation of magnesium sulfate for neuroprotection prior to preterm birth.
- 2023
-
Ingår i: Acta obstetricia et gynecologica Scandinavica. - : John Wiley & Sons. - 1600-0412 .- 0001-6349. ; 102:12, s. 1741-1748
-
Tidskriftsartikel (refereegranskat)abstract
- The risk for brain injury manifested as cerebral palsy is higher in very preterm born children than in term. Prenatal administration of magnesium sulfate (MgSO4 ) has been shown to be neuroprotective and reduces the proportion of very preterm born children later diagnosed with cerebral palsy. A Swedish national clinical practice guideline was implemented in March 2020, stipulating the administration of a single intravenous dose of 6g MgSO4 1-24h prior to delivery before gestational age 32+0, aiming for 90% treatment coverage. The aim of this study was to evaluate the feasibility of this new clinical practice guideline in the first year of its implementation.Data on MgSO4 treatment were collected by reviewing the medical charts of women who gave birth to live born children in gestational age 22+0-31+6 during the period of March 1, 2020 to February 28, 2021, at five Swedish university hospitals. Women with pre-eclampsia, eclampsia, or high elevated liver enzymes low platelets (HELLP) were excluded.A total of 388 women were eligible and 79% received treatment with MgSO4 . Of the 21% not receiving treatment, 9% did not receive treatment due to lack of knowledge about the clinical practice guideline, 9% were not possible to treat and 3% had missing data. The proportion treated increased from 72% to 87% from the first to the last 3months. Of those treated, 81% received the drug within the stipulated timeframe (mean 8.7h, median 3.4h).There was a positive trend over time in the proportion of women receiving MgSO4 treatment, but the a priori target of 90% was not reached during the first year of implementation. Our findings indicate that this target could be reached with additional information to clinicians.
|
|
| 8. |
- Jansson, Anna. K., et al.
(författare)
-
Risk and mortality of testicular cancer in patients with neurodevelopmental or other psychiatric disorders
- 2023
-
Ingår i: British Journal of Cancer. - : Springer Nature. - 0007-0920 .- 1532-1827. ; 128:12, s. 2261-2269
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundBoth testicular germ cell tumours (TGCT) and neurodevelopmental disorders are associated with urogenital malformations. Few studies have investigated the association between psychiatric disorders and TGCT. We investigated whether history of any psychiatric or neurodevelopmental disorder is associated with increased risk or mortality of TGCT.MethodThis is a nested case-control study including 6166 TGCT patients diagnosed during 1992-2014, individually matched for age and calendar period to 61,660 controls. We calculated odds ratios (ORs) for the association between type of psychiatric diagnoses and TGCT risk. Among the cases, we used a cohort design and calculated hazard ratios (HRs) of the association between psychiatric diagnose and all-cause and TGCT-specific death.ResultsHistory of a neurodevelopmental disorder (attention deficit hyperactivity disorder, autism spectrum disorder and intellectual disabilities) was associated with an increased risk of seminoma (OR: 1.54; 1.09-2.19). Seminoma patients with neurodevelopmental disorders were younger (34 versus 38 years, p = 0.004) and had more stage IV disease (5.4% versus 1.2%) than those without. Psychiatric history overall was not associated with TGCT. Patient history of any psychiatric disorder was associated with an increased all-cause and TGCT-specific death.ConclusionsWe report an association between neurodevelopmental disorders and testicular seminoma, and an increased TGCT-specific mortality for TGCT patients with psychiatric disorders.
|
|
| 9. |
- Ljungdahl, Thomas, 1974, et al.
(författare)
-
Geometrically homogeneous series of covalently linked zinc/free-base porphyrin dimers of varying length; design, synthesis and characterization
- 2006
-
Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1099-0690 .- 1434-193X. ; :14, s. 3087-3096
-
Tidskriftsartikel (refereegranskat)abstract
- Singlet excitation energy transfer, SEET, can be mediated by a bridge, connecting an energy donor and acceptor, via a superexchange mechanism. The mediation efficiency depends on the energy difference between the first excited states of the donor and the bridge, DEDB, as well as the donor-acceptor distance, RDA. We have previously constructed a series of donor-bridge-acceptor, D-B-A, systems that allowed us to study how SEET depends on DEDB. To expand this study into a second dimension, the distance dependence, a new series of D-B-A systems were constructed. This series was based on the same zinc/free-base porphyrin couple as the donor-acceptor pair in the previous series. Their relative orientation was also retained. In contrast to our first series, the bridges in the latter were of varying length. The bridges were oligo(phenyleneethynylene)phenylene (OPE) structures and the length was systematically changed by increasing the no. of phenyleneethynylene units from 1 to 4. To obtain high quality samples, the D-B-A systems were assembled by a building block approach where the zinc and free-base porphyrins were introduced sep. using Heck alkynylations. The performance of the OPE structure as a mediator and scaffold is discussed in terms of singlet excited state energies and flexibility. For the first time, when combining the topical D-B-A systems with our previous subset, a homogeneous series of D-B-A systems has been synthesized that allows for studies of both the distance dependence and the energy difference dependence of SEET.
|
|
| 10. |
- Ljungdahl, Thomas, 1974, et al.
(författare)
-
Solvent and base dependence of copper-free palladium-catalyzed cross-couplings between terminal alkynes and arylic iodides: Development of efficient conditions for the construction of gold(III)/free-base porphyrin dimers
- 2006
-
Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 71:4, s. 1677-1687
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, our attempts to optimize the Heck alkynylation (copper-free Sonogashira) reaction are presented. An efficient copper-free coupling protocol was needed for the synthesis of gold/zinc porphyrin dimers because previous methods had failed. Previous studies have usually focused on ligands, whereas this work focuses on the choice of solvent and base. The catalytic system throughout the investigation was formed from the stable precursor [Pd-2(dba)(3)center dot CHCl3] together with the ligand triphenylarsine, an easy-to-handle, air-stable ligand. A model study was conducted to examine the dependence of the Heck alkynylation on the solvent and base. The most successful modification proved to be the addition of methanol, as a cosolvent, in combination with a nucleophilic tertiary base. The success of the methanol additive is hypothesized to be caused by the presence of a rate-determining deprotonation step featuring a charge-separated transition state. Finally, the very high yielding and successful synthesis of a series of porphyrin systems using these new conditions is presented. For the first time, gold porphyrin substrates could efficiently be coupled in Heck alkynylation reactions.
|
|
| 11. |
- Pettersson, Karin, 1975, et al.
(författare)
-
Interplay between Barrier Width and Height in Electron Tunneling: Photoinduced Electron Transfer in Porphyrin-Based Donor-Bridge-Acceptor Systems
- 2006
-
Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 110:1, s. 319-326
-
Tidskriftsartikel (refereegranskat)abstract
- The rate of electron tunneling in mol. donor-bridge-acceptor (D-B-A) systems is detd. both by the tunneling barrier width and height, i.e., both by the distance between the donor and acceptor as well as by the energy gap between the donor and bridge moieties. These factors are therefore important to control when designing functional electron transfer systems, such as constructs for photovoltaics, artificial photosynthesis, and mol. scale electronics. The authors have studied a set of D-B-A systems in which the distance and the energy difference between the donor and bridge states (DEDB) are systematically varied. Zinc(II) and gold(III) porphyrins were chosen as electron donor and acceptor because of their suitable driving force for photoinduced electron transfer (-0.9 eV in butyronitrile) and well-characterized photophysics. The authors have previously shown, in accordance with the superexchange mechanism for electron transfer, that the electron transfer rate is proportional to the inverse of DEDB in zinc/gold porphyrin D-B-A systems with bridges of const. edge to edge distance (19.6 .ANG.) and varying DEDB (3900-17,600 cm-1). Here, the authors use the same donor and acceptor but the bridge is shortened or extended giving a set of oligo-p-phenyleneethynylene bridges (OPE) with four different edge to edge distances ranging from 12.7 to 33.4 .ANG.. These two sets of D-B-A systems-ZnP-RB-AuP+ and ZnP-nB-AuP+-have one bridge in common, and hence, for the first time both the distance and DEDB dependence of electron transfer can be studied simultaneously in a systematic way. [on SciFinder (R)]
|
|
| 12. |
- Pettersson, Karin, 1975, et al.
(författare)
-
Intersystem Crossing versus Electron Transfer in Porphyrin-Based Donor-Bridge-Acceptor Systems: Influence of a Paramagnetic Species
- 2004
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 126:21, s. 6710-6719
-
Tidskriftsartikel (refereegranskat)abstract
- We have investigated how the spin state of an acceptor influences the photophysical processes in a donor-bridge-acceptor (D-B-A) system. The system of choice has zinc porphyrin as the electron donor and high-or low-spin iron(III) porphyrin as the acceptor. The spin state of the acceptor porphyrin is switched simply by coordinating imidazole ligands to the metal center. The D-A center-center distance is 26 Angstrom, and the bridging chromophore varies from g-conjugated to a sigma-bonded system. The presence of a high-spin iron(III) porphyrin in such systems has previously been shown to significantly enhance intersystem crossing in the remote zinc porphyrin donor, whereas no significant electron transfer to the iron porphyrin acceptor was observed, even though the thermodynamics would allow for photoincluced electron transfer. Here, we demonstrate that by switching the acceptor to a low-spin state, the dominating photophysical process is drastically changed; the low-spin system shows long-range electron transfer on the picosecond time-scale, and intersystem crossing occurs at its "normal" rate.
|
|
| 13. |
|
|
| 14. |
- Pettersson, Karin, 1975, et al.
(författare)
-
Singlet Energy Transfer in Porphyrin-Based Donor-Bridge-Acceptor Systems: Interaction between Bridge Length and Bridge Energy
- 2006
-
Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 110:1, s. 310-318
-
Tidskriftsartikel (refereegranskat)abstract
- Singlet excitation energy transfer is governed by two donor-acceptor interactions, the Coulombic and exchange interactions giving rise to the Foerster and Dexter mechanisms, resp., for singlet energy transfer. In transfer between colliding mols. or between a donor (D) and acceptor (A) connected in donor-bridge-acceptor (D-B-A) system by an inert spacer (B), the distinction between these two mechanisms is quite clear. However, in D-B-A systems connected by a p-conjugated bridge, the exchange interaction between the donor and acceptor is mediated by the virtual low-lying excited states (unoccupied orbitals) of that bridge and, as a consequence, becomes much more long-range in character. Thus, the clear distinction to the Coulombic mechanism is lost. This so-called superexchange mechanism for singlet energy transfer has been shown to make a significant contribution to the energy transfer rates in several D-B-A systems, and its D-A distance as well as D-B energy gap dependencies have been studied. We here demonstrate that in a series of oligo-p-phenyleneethynylene (OPE) bridged porphyrin-based D-B-A systems with varying D-A distances the Foerster and through-bond (superexchange) mechanisms both make considerable contributions to the obsd. singlet energy transfer rates. The donor is either a zinc porphyrin or a zinc porphyrin with a pyridine ligand, and the acceptor is a free base porphyrin. By comparison to a homologous series where only the D-B energy gaps varies, a sepn. between the two energy transfer mechanisms was possible and, moreover, an interplay between distance and energy gap dependencies was noted. The distance dependence was shown to be approx. exponential with an attenuation factor b = 0.20 .ANG.-1. If the effect of the varying D-B energy gaps in the OPE series was taken into account, a slightly higher b-value was obtained. Ground-state absorption, steady-state, and time-resolved emission spectroscopy were used. The exptl. study is accompanied by time-dependent d. functional theory (TD-DFT) calcns. of the electronic coupling, and the exptl. and theor. results are in excellent qual. agreement (same distance dependence).
|
|
| 15. |
- Pettersson, Karin, 1975
(författare)
-
Tuning of Energy and Electron Transfer Rates in Donor-Bridge-Acceptor Systems
- 2007
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The intramolecular processes of Donor-Bridge-Acceptor (D-B-A) systems have been investigated by spectroscopic methods. The systems consist of porphyrin donors and acceptors linked by oligo-p-phenyleneethynylene bridges. Two series of bridges have been used: one where the energy splitting between the singlet excited states of the donor and bridge (EDB) varies at constant length and one where the bridge length and EDB vary. By changing the metalation state of the acceptor porphyrin different intramolecular processes have been studied separately.It was shown that the rate of energy and electron transfer has a strong distance dependence and a EDB dependence. It was concluded that theEDB dependence is important in D-B-A systems with small EDB and/or large variation of EDB within a set of bridges. Further, it was shown that the attenuation factor, , is a system specific parameter and not only bridge specific as generally claimed.In a D-B-A system with small EDB it was found that a sequential transfer mechanism can be turned on and off by changing the temperature and/or solvent polarity. At high temperatures in polar solvents direct electron transfer and sequential electron transfer act in parallel but at low temperature or in non-polar solvents the direct process dominates.Finally, it was demonstrated that by changing the spin of a paramagnetic acceptor the main deactivation process changes. Electron transfer dominates in the low spin configuration whereas energy transfer and enhanced intersystem crossing are the main deactivation processes in the high spin configuration.
|
|
| 16. |
- Wiberg, Joanna, 1980, et al.
(författare)
-
Charge recombination versus charge separation in donor-bridge-acceptor systems
- 2007
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 129:1, s. 155-163
-
Tidskriftsartikel (refereegranskat)abstract
- Optimizing the ratio of the rates for charge separation (CS) over charge recombination (CR) is crucial to create long-lived charge-separated states. Mastering the factors that govern the electron transfer (ET) rates is essential when trying to achieve molecular-scale electronics, artificial photosynthesis, and also for the further development of solar cells. Much work has been put into the question of how the donor-acceptor distances and donor-bridge energy gaps affect the electronic coupling, V DA , and thus the rates of ET. We present here a unique comparison on how these factors differently influence the rates for CS and CR in a porphyrin-based donor-bridge-acceptor model system. Our system contains three series, each of which focuses on a separate charge-transfer rate-determining factor, the donor-acceptor distance, the donor-bridge energy gap, and last, the influence of the electron acceptor on the rate for charge transfer. In these three series both CS and CR are governed by superexchange interactions which make a CR/CS comparative study ideal. We show here that the exponential distance dependence increases slightly for CR compared to that for CS as a result of the increased tunneling barrier height for this reaction, in accordance with the McConnell superexchange model. We also show that the dependence on the tunneling barrier height is different for CS and CR. This difference is highly dependent on the electron acceptor and thus cannot solely be explained by the differences in the frontier orbitals of the electron donor in these porphyrin systems. © 2007 American Chemical Society.
|
|
| 17. |
|
|
