A new method for the determination of low-level actinium-227 in geological samples

Author Posting. © The Author(s), 2012. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Journal of Radioanalytical and Nuclear Chemistry 296 (2013): 279-283, doi:10.1007/s10967-012-2140-0.We developed a new method for the determination of 227Ac in geological samples. The method uses extraction chromatographic techniques and alpha-spectrometry and is applicable for a range of natural matrices. Here we report on the procedure and results of the analysis of water (fresh and seawater) and rock samples. Water samples were acidified and rock samples underwent total dissolution via acid leaching. A DGA (N,N,N’,N’-tetra-n-octyldiglycolamide) extraction chromatographic column was used for the separation of actinium. The actinium fraction was prepared for alpha spectrometric measurement via cerium fluoride micro-precipitation. Recoveries of actinium in water samples were 80±8 % (number of analyses n=14) and in rock samples 70±12 % (n=30). The minimum detectable activities (MDA) were 0.017-0.5 Bq kg-1 for both matrices. Rock sample 227Ac activities ranged from 0.17 to 8.3 Bq kg-1 and water sample activities ranged from below MDA values to 14 Bq kg-1of 227Ac. From the analysis of several standard rock and water samples with the method we found very good agreement between our results and certified values

Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 years

The Arctic Ocean has an important role in Earth’s climate, both through surface processes such as sea-ice formation and transport, and through the production and export of waters at depth that contribute to the global thermohaline circulation. Deciphering the deep Arctic Ocean’s palaeo-oceanographic history is a crucial part of understanding its role in climatic change. Here we show that sedimentary ratios of the radionuclides thorium-230 (230Th) and protactinium-231 (231Pa), which are produced in sea water and removed by particle scavenging on timescales of decades to centuries, respectively, record consistent evidence for the export of 231Pa from the deep Arctic and may indicate continuous deep-water exchange between the Arctic and Atlantic oceans throughout the past 35,000 years. Seven well-dated box-core records provide a comprehensive overview of 231Pa and 230Th burial in Arctic sediments during glacial, deglacial and interglacial conditions. Sedimentary 231Pa/230Th ratios decrease nearly linearly with increasing water depth above the core sites, indicating efficient particle scavenging in the upper water column and greater influence of removal by lateral transport at depth. Although the measured 230Th burial is in balance with its production in Arctic sea water, integrated depth profiles for all time intervals reveal a deficit in 231Pa burial that can be balanced only by lateral export in the water column. Because no enhanced sink for 231Pa has yet been found in the Arctic, our records suggest that deep-water exchange through the Fram strait may export 231Pa. Such export may have continued for the past 35,000 years, suggesting a century-scale replacement time for deep waters in the Arctic Ocean since the most recent glaciation and a persistent contribution of Arctic waters to the global ocean circulation

The Spin Structure of the Nucleon

We present an overview of recent experimental and theoretical advances in our understanding of the spin structure of protons and neutrons.Comment: 84 pages, 29 figure

Comparison of the efficacy of a neutral wrist splint and wrist splint with lumbrical unit for the treatment of patients with carpal tunnel syndrome

Purpose: The purpose of this study was to compare the effect of a neutral wrist splint or a wrist splint with an additional metacarpophalangeal (MCP) unit on pain, function, grip and pinch strength in patients with mild-to-moderate carpal tunnel syndrome (CTS). Methods: Twenty four patients received conservative treatment using either the neutral wrist splint or wrist splint with the MCP unit for a period of 6 weeks. Primary outcome measures were pain, function, grip and pinch strength. Data was collected immediately before and after using the two types of splints at baseline (0 weeks) and 6 weeks. Statistical analysis was performed using the paired t-test and independent T-test. Results: Compared to baseline, both the neutral wrist splint and the wrist splint with an MCP unit significantly decreased pain, increased function and pinch and grip strength. Comparisons of the two types of splints for grip (P =0.675) and pinch strength (P =0.650) revealed that there were no significant differences between the two after 6 weeks of wear. However, there were significant differences in pain levels (P =0.022) and the DASH score (P =0.027) between the two types of splints from baseline to 6 weeks. Conclusion: The wrist splint with an MCP unit was more effective than the neutral wrist splint in pain reduction and improvement of function

Inter-observer reproducibility of measurements of range of motion in patients with shoulder pain using a digital inclinometer

BACKGROUND: Reproducible measurements of the range of motion are an important prerequisite for the interpretation of study results. The digital inclinometer is considered to be a useful instrument because it is inexpensive and easy to use. No previous study assessed inter-observer reproducibility of range of motion measurements with a digital inclinometer by physical therapists in a large sample of patients. METHODS: Two physical therapists independently measured the passive range of motion of the glenohumeral abduction and the external rotation in 155 patients with shoulder pain. Agreement was quantified by calculation of the mean differences between the observers and the standard deviation (SD) of this difference and the limits of agreement, defined as the mean difference ± 1.96*SD of this difference. Reliability was quantified by means of the intraclass correlation coefficient (ICC). RESULTS: The limits of agreement were 0.8 ± 19.6 for glenohumeral abduction and -4.6 ± 18.8 for external rotation (affected side) and quite similar for the contralateral side and the differences between sides. The percentage agreement within 10° for these measurements were 72% and 70% respectively. The ICC ranged from 0.28 to 0.90 (0.83 and 0.90 for the affected side). CONCLUSIONS: The inter-observer agreement was found to be poor. If individual patients are assessed by two different observers, differences in range of motion of less than 20–25 degrees can not be distuinguished from measurement error. In contrast, acceptable reliability was found for the inclinometric measurements of the affected side and the differences between the sides, indicating that the inclimeter can be used in studies in which groups are compared

(Per)chlorate reduction by an acetogenic bacterium, Sporomusa sp., isolated from an underground gas storage

A mesophilic bacterium, strain An4, was isolated from an underground gas storage reservoir with methanol as substrate and perchlorate as electron acceptor. Cells were Gram-negative, spore-forming, straight to curved rods, 0.5–0.8 μm in diameter, and 2–8 μm in length, growing as single cells or in pairs. The cells grew optimally at 37°C, and the pH optimum was around 7. Strain An4 converted various alcohols, organic acids, fructose, acetoin, and H2/CO2 to acetate, usually as the only product. Succinate was decarboxylated to propionate. The isolate was able to respire with (per)chlorate, nitrate, and CO2. The G+C content of the DNA was 42.6 mol%. Based on the 16S rRNA gene sequence analysis, strain An4 was most closely related to Sporomusa ovata (98% similarity). The bacterium reduced perchlorate and chlorate completely to chloride. Key enzymes, perchlorate reductase and chlorite dismutase, were detected in cell-free extracts

Dealing with Feelings: Characterization of Trait Alexithymia on Emotion Regulation Strategies and Cognitive-Emotional Processing

Background: Alexithymia, or "no words for feelings'', is a personality trait which is associated with difficulties in emotion recognition and regulation. It is unknown whether this deficit is due primarily to regulation, perception, or mentalizing of emotions. In order to shed light on the core deficit, we tested our subjects on a wide range of emotional tasks. We expected the high alexithymics to underperform on all tasks. Method: Two groups of healthy individuals, high and low scoring on the cognitive component of the Bermond-Vorst Alexithymia Questionnaire, completed questionnaires of emotion regulation and performed several emotion processing tasks including a micro expression recognition task, recognition of emotional prosody and semantics in spoken sentences, an emotional and identity learning task and a conflicting beliefs and emotions task (emotional mentalizing). Results: The two groups differed on the Emotion Regulation Questionnaire, Berkeley Expressivity Questionnaire and Empathy Quotient. Specifically, the Emotion Regulation Quotient showed that alexithymic individuals used more suppressive and less reappraisal strategies. On the behavioral tasks, as expected, alexithymics performed worse on recognition of micro expressions and emotional mentalizing. Surprisingly, groups did not differ on tasks of emotional semantics and prosody and associative emotional-learning. Conclusion: Individuals scoring high on the cognitive component of alexithymia are more prone to suppressive emotion regulation strategies rather than reappraisal strategies. Regarding emotional information processing, alexithymia is associated with reduced performance on measures of early processing as well as higher order mentalizing. However, difficulties in the processing of emotional language were not a core deficit in our alexithymic group

Genetic analysis of the interaction between Allium species and arbuscular mycorrhizal fungi

The response of Alliumcepa, A. roylei, A. fistulosum, and the hybrid A. fistulosum × A. roylei to the arbuscular mycorrhizal fungus (AMF) Glomus intraradices was studied. The genetic basis for response to AMF was analyzed in a tri-hybrid A. cepa × (A. roylei × A. fistulosum) population. Plant response to mycorrhizal symbiosis was expressed as relative mycorrhizal responsiveness (R′) and absolute responsiveness (R). In addition, the average performance (AP) of genotypes under mycorrhizal and non-mycorrhizal conditions was determined. Experiments were executed in 2 years, and comprised clonally propagated plants of each genotype grown in sterile soil, inoculated with G. intraradices or non-inoculated. Results were significantly correlated between both years. Biomass of non-mycorrhizal and mycorrhizal plants was significantly positively correlated. R′ was negatively correlated with biomass of non-mycorrhizal plants and hence unsuitable as a breeding criterion. R and AP were positively correlated with biomass of mycorrhizal and non-mycorrhizal plants. QTLs contributing to mycorrhizal response were located on a linkage map of the A. roylei × A. fistulosum parental genotype. Two QTLs from A. roylei were detected on chromosomes 2 and 3 for R, AP, and biomass of mycorrhizal plants. A QTL from A. fistulosum was detected on linkage group 9 for AP (but not R), biomass of mycorrhizal and non-mycorrhizal plants, and the number of stem-borne roots. Co-segregating QTLs for plant biomass, R and AP indicate that selection for plant biomass also selects for enhanced R and AP. Moreover, our findings suggest that modern onion breeding did not select against the response to AMF, as was suggested before for other cultivated species. Positive correlation between high number of roots, biomass and large response to AMF in close relatives of onion opens prospects to combine these traits for the development of more robust onion cultivars