| 1. |
- Byström, Johan, et al.
(författare)
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Reiterated homogenization of degenerate nonlinear elliptic equations
- 2002
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Ingår i: Chinese Annals of Mathematics. Series B. - 0252-9599 .- 1860-6261. ; 23:3, s. 325-334
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Tidskriftsartikel (refereegranskat)abstract
- The authors study homogenization of some nonlinear partial differential equations of the form _ div (a (hx, h2 x, Duh)) = f , where a is periodic in the rst two arguments and monotone in the third. In particular the case where a satis es degenerated structure conditions is studied. It is proved that uh converges weakly in W0 1,1 (Ω) to the unique solution of a limit problem as h → ∞ . Moreover, explicit expressions for the limit problem are obtained.
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| 2. |
- Mohr, Barbara, et al.
(författare)
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Trifurcatia flabellata n. gen. n. sp., a putative monocotyledon angiosperm from the Lower Cretaceous Crato Formation (Brazil)
- 2002
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Ingår i: Fossil Record. - : Pensoft Publishers. - 1435-1943 .- 1860-1014. ; 5:1, s. 335-344
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Tidskriftsartikel (refereegranskat)abstract
- The Lower Cretaceous Crato Formation (northeast Brazil) contains plant remains, here described as Trifurcatia flabellata n. gen. and n. sp., consisting of shoot fragments with jointed trifurcate axes, each axis bearing a single amplexicaul serrate leaf at the apex. The leaves show a flabellate acrodromous to parallelodromous venation pattern, with several primary, secondary and higher order cross-veins. This very unique fossil taxon shares many characters with monocots. However, this fossil taxon exhibits additional features which point to a partly reduced, and specialized plant, which probably enabled this plant to grow in (seasonally) dry, even salty environments. In der unterkretazischen Cratoformation (Nordostbrasilien) sind Pflanzenfossilien erhalten, die hier als Trifurcatia flabellata n. gen. n. sp. beschrieben werden. Sie bestehen aus trifurcaten Achsen, mit einem apikalen amplexicaulen fächerförmigen serraten Blatt. Diese Blätter zeigen eine flabellate bis acrodrome-paralellodrome Aderung mit Haupt- und Nebenadern und transversale Adern 3. Ordnung. Diese Merkmale sind typisch für Monocotyledone. Allerdings weist dieses Taxon einige Merkmale auf, die weder bei rezenten noch fossilen Monocotyledonen beobachtet werden. Sie müssen als besondere Anpassungen an einen (saisonal) trockenen und vielleicht übersalzenen Lebensraum dieser Pflanze interpretiert werden.
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| 3. |
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| 4. |
- Bailey, D. L., et al.
(författare)
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Combined PET/MRI : Global Warming-Summary Report of the 6th International Workshop on PET/MRI, March 27-29, 2017, Tubingen, Germany
- 2018
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Ingår i: Molecular Imaging and Biology. - : SPRINGER. - 1536-1632 .- 1860-2002. ; 20:1, s. 4-20
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Forskningsöversikt (refereegranskat)abstract
- The 6th annual meeting to address key issues in positron emission tomography (PET)/magnetic resonance imaging (MRI) was held again in Tubingen, Germany, from March 27 to 29, 2017. Over three days of invited plenary lectures, round table discussions and dialogue board deliberations, participants critically assessed the current state of PET/MRI, both clinically and as a research tool, and attempted to chart future directions. The meeting addressed the use of PET/MRI and workflows in oncology, neurosciences, infection, inflammation and chronic pain syndromes, as well as deeper discussions about how best to characterise the tumour microenvironment, optimise the complementary information available from PET and MRI, and how advanced data mining and bioinformatics, as well as information from liquid biomarkers (circulating tumour cells and nucleic acids) and pathology, can be integrated to give a more complete characterisation of disease phenotype. Some issues that have dominated previous meetings, such as the accuracy of MR-based attenuation correction (AC) of the PET scan, were finally put to rest as having been adequately addressed for the majority of clinical situations. Likewise, the ability to standardise PET systems for use in multicentre trials was confirmed, thus removing a perceived barrier to larger clinical imaging trials. The meeting openly questioned whether PET/MRI should, in all cases, be used as a whole-body imaging modality or whether in many circumstances it would best be employed to give an in-depth study of previously identified disease in a single organ or region. The meeting concluded that there is still much work to be done in the integration of data from different fields and in developing a common language for all stakeholders involved. In addition, the participants advocated joint training and education for individuals who engage in routine PET/MRI. It was agreed that PET/MRI can enhance our understanding of normal and disrupted biology, and we are in a position to describe the in vivo nature of disease processes, metabolism, evolution of cancer and the monitoring of response to pharmacological interventions and therapies. As such, PET/MRI is a key to advancing medicine and patient care.
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| 5. |
- Bailey, D. L., et al.
(författare)
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Combined PET/MRI : from Status Quo to Status Go. Summary Report of the Fifth International Workshop on PET/MR Imaging; February 15-19, 2016; Tubingen, Germany
- 2016
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Ingår i: Molecular Imaging and Biology. - : Springer Science and Business Media LLC. - 1536-1632 .- 1860-2002. ; 18:5, s. 637-650
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Tidskriftsartikel (refereegranskat)abstract
- This article provides a collaborative perspective of the discussions and conclusions from the fifth international workshop of combined positron emission tomorgraphy (PET)/magnetic resonance imaging (MRI) that was held in Tubingen, Germany, from February 15 to 19, 2016. Specifically, we summarise the second part of the workshop made up of invited presentations from active researchers in the field of PET/MRI and associated fields augmented by round table discussions and dialogue boards with specific topics. This year, this included practical advice as to possible approaches to moving PET/MRI into clinical routine, the use of PET/MRI in brain receptor imaging, in assessing cardiovascular diseases, cancer, infection, and inflammatory diseases. To address perceived challenges still remaining to innovatively integrate PET and MRI system technologies, a dedicated round table session brought together key representatives from industry and academia who were engaged with either the conceptualisation or early adoption of hybrid PET/MRI systems. Discussions during the workshop highlighted that emerging unique applications of PET/MRI such as the ability to provide multi-parametric quantitative and visual information which will enable not only overall disease detection but also disease characterisation would eventually be regarded as compelling arguments for the adoption of PET/MR. However, as indicated by previous workshops, evidence in favour of this observation is only growing slowly, mainly due to the ongoing inability to pool data cohorts from independent trials as well as different systems and sites. The participants emphasised that moving from status quo to status go entails the need to adopt standardised imaging procedures and the readiness to act together prospectively across multiple PET/MRI sites and vendors.
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| 6. |
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| 7. |
- Delaney, Samantha, et al.
(författare)
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Site-Specific Photoaffinity Bioconjugation for the Creation of 89Zr-Labeled Radioimmunoconjugates
- 2023
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Ingår i: Molecular Imaging and Biology. - : Springer Nature. - 1536-1632 .- 1860-2002. ; 25:6, s. 1104-1114
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Site-specific approaches to bioconjugation produce well-defined and homogeneous immunoconjugates with potential for superior in vivo behavior compared to analogs synthesized using traditional, stochastic methods. The possibility of incorporating photoaffinity chemistry into a site-specific bioconjugation strategy is particularly enticing, as it could simplify and accelerate the preparation of homogeneous immunoconjugates for the clinic. In this investigation, we report the synthesis, in vitro characterization, and in vivo evaluation of a site-specifically modified, 89Zr-labeled radioimmunoconjugate created via the reaction between an mAb and an Fc-binding protein bearing a photoactivatable 4-benzoylphenylalanine residue. Procedures: A variant of the Fc-binding Z domain of protein A containing a photoactivatable, 4-benzoylphenylalanine residue — Z(35BPA) — was modified with desferrioxamine (DFO), combined with the A33 antigen-targeting mAb huA33, and irradiated with UV light. The resulting immunoconjugate — DFOZ(35BPA)-huA33 — was purified and characterized via SDS-PAGE, MALDI-ToF mass spectrometry, surface plasmon resonance, and flow cytometry. The radiolabeling of DFOZ(35BPA)-huA33 was optimized to produce [89Zr]Zr-DFOZ(35BPA)-huA33, and the immunoreactivity of the radioimmunoconjugate was determined with SW1222 human colorectal cancer cells. Finally, the in vivo performance of [89Zr]Zr-DFOZ(35BPA)-huA33 in mice bearing subcutaneous SW1222 xenografts was interrogated via PET imaging and biodistribution experiments and compared to that of a stochastically labeled control radioimmunoconjugate, [89Zr]Zr-DFO-huA33. Results: HuA33 was site-specifically modified with Z(35BPA)-DFO, producing an immunoconjugate with on average 1 DFO/mAb, high in vitro stability, and high affinity for its target. [89Zr]Zr-DFOZ(35BPA)-huA33 was synthesized in 95% radiochemical yield and exhibited a specific activity of 2 mCi/mg and an immunoreactive fraction of ~ 0.85. PET imaging and biodistribution experiments revealed that high concentrations of the radioimmunoconjugate accumulated in tumor tissue (i.e., ~ 40%ID/g at 120 h p.i.) but also that the Z(35BPA)-bearing immunoPET probe produced higher uptake in the liver, spleen, and kidneys than its stochastically modified cousin, [89Zr]Zr-DFO-huA33. Conclusions: Photoaffinity chemistry and an Fc-binding variant of the Z domain were successfully leveraged to create a novel site-specific strategy for the synthesis of radioimmunoconjugates. The probe synthesized using this method — DFOZ(35BPA)-huA33 — was well-defined and homogeneous, and the resulting radioimmunoconjugate ([89Zr]Zr-DFOZ(35BPA)-huA33) boasted high specific activity, stability, and immunoreactivity. While the site-specifically modified radioimmunoconjugate produced high activity concentrations in tumor tissue, it also yielded higher uptake in healthy organs than a stochastically modified analog, suggesting that optimization of this system is necessary prior to clinical translation.
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| 9. |
- Eskola, Olli, et al.
(författare)
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Tracer Level Electrophilic Synthesis and Pharmacokinetics of the Hypoxia Tracer [F-18]EF5
- 2012
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Ingår i: Molecular Imaging and Biology. - : Springer Science and Business Media LLC. - 1536-1632 .- 1860-2002. ; 14:2, s. 205-212
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Tidskriftsartikel (refereegranskat)abstract
- 2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide labeled with [F-18]-fluorine ([F-18]EF5), a promising tracer for tumor hypoxia, has previously been synthesized in low yields and low specific radioactivity. In pharmacokinetic evaluations, in the presence of non-radioactive EF5, a uniform and low background uptake and high in vivo stability of [F-18]EF5 have been demonstrated. Our purpose was to increase the specific radioactivity of [F-18]EF5 to enable to study the pharmacokinetics at trace level. [F-18]EF5 was synthesized using high specific radioactivity electrophilic [F-18]F-2 as labelling reagent. Biodistribution of [F-18]EF5 was determined in a prostate tumor mouse model, and formation of radiolabelled metabolites was studied in mouse, rat and human plasma. On average, 595 +/- 153 MBq of [F-18]EF5 was produced. Specific radioactivity was 6.6 +/- 1.9 GBq/mu mol and the radiochemical purity exceeded 99.0%. [F-18]EF5 was distributed uniformly in tissues, with highest uptake in liver, kidney, and intestine. Several radiolabelled metabolites were detected in mouse plasma and tissues, whereas low amounts of metabolites were detected in human and rat plasma. [F-18]EF5 was synthesized by electrophilic labelling with high quality and high yields. Pharmacokinetics of [F-18]EF5 was determined at trace level in several species. Our results suggest that the trace-level approach does not affect the biodistribution of [F-18]EF5. Extensive metabolism was seen in mouse.
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| 10. |
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