| 1. |
|
|
| 2. |
|
|
| 3. |
- Cox, Nicholas, et al.
(författare)
-
The S-1 split signal of photosystem II : a tyrosine-manganese coupled interaction
- 2009
-
Ingår i: Biochimica et Biophysica Acta - Bioenergetics. - : Elsevier BV. - 0005-2728 .- 1879-2650. ; 1787:7, s. 882-889
-
Tidskriftsartikel (refereegranskat)abstract
- Detailed optical and EPR analyses of states induced in dark-adapted PS II membranes by cryogenic illumination permit characterization and quantification of all pigment derived donors and acceptors, as well as optically silent (in the visible, near infrared) species which are EPR active. Near complete turnover formation of Q(A)(-) is seen in all centers, but with variable efficiency, depending on the donor species. In minimally detergent-exposed PS II membranes, negligible (<5%) oxidation of chlorophyll or carotenoid centers occurs for illumination temperatures 5-20 K. An optically silent electron donor to P680(+) is observed with the same decay kinetics as the S-1 split signal. Cryogenic donors to P680(+) seen are: (i) transient (t(1/2)similar to 150 s) tyrosine related species, including 'split signals' (similar to 15% total centers), (ii) reduced cytochrome b(559) (similar to 30-50% centers), and (iii) an organic donor, possibly an amino acid side chain, (similar to 30% centers).
|
|
| 4. |
- Poehlman, Melanie, et al.
(författare)
-
Magnetic microbubbles for multimodality imaging : the importance of the shell structure for low and high frequency mechanics
- 2013
-
Konferensbidrag (refereegranskat)abstract
- There is a growing interest in magnetic microbubbles (MBs) for simultaneous enhanced ultrasound (US) and enhanced magnetic resonance imaging (MRI) to support well-established imaging procedures as well as new emerging diagnostic and therapeutic applications. However, the development of hybrid contrast agents is challenging, because their design needs to satisfy a variety of requirements such as a sufficient stability of the probe for the circulation within the cardiovascular system, the production of an adequate US echo signal and a reasonable reduced relaxation time of nearby located protons. The studied magnetic MBs consist of an air-filled core, which is encapsulated by a soft hydrogel-like shell composed of poly(vinyl alcohol) and superparamagnetic iron oxide nanoparticles (SPIONs)[1]. Two strategies were used to combine magnetic nanoparticles with the polymeric shell: SPIONs were either covalently attached to the shell surface via a post-chemical treatment or embedded physically inside the shell during the MBs’ synthesis. In particular, we were interested on the impact of the used SPIONs integration strategy on low and high frequency mechanics of the magnetic MBs. Therefore, we used a straightforward characterization of the MBs on the single particle level to correlate the synthesis with the MBs’ morphological properties and low frequency mechanics that were studied in quasi-static force measurements with atomic force microscopy. High frequency mechanics were investigated by exposure of an ensemble of MBs to an acoustic field. By further correlation of low and high frequency mechanics, we were able to bridge the gap between synthesis and the MBs macroscopic properties relevant for their application. The shown approach offers the possibility to sustainable design and optimize complex probes based on an improved understanding of structure/property relations.
|
|
| 5. |
- Schindler, Birgit Karin, et al.
(författare)
-
The European COPHES/DEMOCOPHES project: Towards transnational comparability and reliability of human biomonitoring results.
- 2014
-
Ingår i: International Journal of Hygiene and Environmental Health. - : Elsevier BV. - 1618-131X .- 1438-4639. ; 217:6, s. 653-661
-
Tidskriftsartikel (refereegranskat)abstract
- COPHES/DEMOCOPHES has its origins in the European Environment and Health Action Plan of 2004 to "develop a coherent approach on human biomonitoring (HBM) in Europe". Within this twin-project it was targeted to collect specimens from 120 mother-child-pairs in each of the 17 participating European countries. These specimens were investigated for six biomarkers (mercury in hair; creatinine, cotinine, cadmium, phthalate metabolites and bisphenol A in urine). The results for mercury in hair are described in a separate paper. Each participating member state was requested to contract laboratories, for capacity building reasons ideally within its borders, carrying out the chemical analyses. To ensure comparability of analytical data a Quality Assurance Unit (QAU) was established which provided the participating laboratories with standard operating procedures (SOP) and with control material. This material was specially prepared from native, non-spiked, pooled urine samples and was tested for homogeneity and stability. Four external quality assessment exercises were carried out. Highly esteemed laboratories from all over the world served as reference laboratories. Web conferences after each external quality assessment exercise functioned as a new and effective tool to improve analytical performance, to build capacity and to educate less experienced laboratories. Of the 38 laboratories participating in the quality assurance exercises 14 laboratories qualified for cadmium, 14 for creatinine, 9 for cotinine, 7 for phthalate metabolites and 5 for bisphenol A in urine. In the last of the four external quality assessment exercises the laboratories that qualified for DEMOCOPHES performed the determinations in urine with relative standard deviations (low/high concentration) of 18.0/2.1% for cotinine, 14.8/5.1% for cadmium, 4.7/3.4% for creatinine. Relative standard deviations for the newly emerging biomarkers were higher, with values between 13.5 and 20.5% for bisphenol A and between 18.9 and 45.3% for the phthalate metabolites. Plausibility control of the HBM results of all participating countries disclosed analytical shortcomings in the determination of Cd when using certain ICP/MS methods. Results were corrected by reanalyzes. The COPHES/DEMOCOPHES project for the first time succeeded in performing a harmonized pan-European HBM project. All data raised have to be regarded as utmost reliable according to the highest international state of the art, since highly renowned laboratories functioned as reference laboratories. The procedure described here, that has shown its success, can be used as a blueprint for future transnational, multicentre HBM projects.
|
|
