96 research outputs found
Means of Introducing an Analyte into Liquid Sampling Atmospheric Pressure Glow Discharge
A liquid sampling, atmospheric pressure, glow discharge (LS-APGD) device as well as systems that incorporate the device and methods for using the device and systems are described. The LS-APGD includes a hollow capillary for delivering an electrolyte solution to a glow discharge space. The device also includes a counter electrode in the form of a second hollow capillary that can deliver the analyte into the glow discharge space. A voltage across the electrolyte solution and the counter electrode creates the microplasma within the glow discharge space that interacts with the analyte to move it to a higher energy state (vaporization, excitation, and/or ionization of the analyte)
Green beach vegetation dynamics explained by embryo dune development
Sandy coastlines are dynamic environments with potential for biodiverse habitats, such as green beaches. Green beach vegetation can develop on nutrient-poor beaches landward from embryo dunes. It is characterised by low-dynamic coastal wetland habitat such as salt marshes and dune slacks. It has been hypothesised that the establishment of green beach vegetation is facilitated by the shelter provided by embryo dunes, however evidence is lacking. We explored the importance of geomorphology and soil conditions on the species richness and turnover of green beach vegetation over a time period of 10 years. We recorded 107 plots along 11 transects over a gradient from beach to dune on the island of Schiermonnikoog, the Netherlands. We characterised transect geomorphology at transect level and soil conditions and vegetation at plot level in 2006 and 2016. We found that the green beach vegetation was highly dynamic, total plant cover increased by 62% within 10 years. In 2006 beach width was an important factor in explaining species richness, with the highest number of species occurring on narrow beaches with a large volume of embryo dunes. In 2016, species richness was positively associated with the build-up of organic matter. Overall species richness declined relative to 2006 and was accompanied by an increase in elevation due to sand burial and the expansion of embryo dune volume. Our data suggests that geomorphology influenced the vegetation indirectly by affecting sand burial rate. Plant species richness declined less at sheltered conditions where sand burial was limited, allowing the build-up of organic matter. This indicates a time-dependent relationship between the development of embryo dunes and plant species richness: embryo dunes can be a source of shelter, thus increasing species richness, but can compete for space over time, lowering species richness again. Our results are relevant for engineering and management of biodiverse sandy shores
Characteristics and health outcomes associated with activation for self-management in patients with non-specific low back pain: A cross-sectional study
Background: Research has shown that the course of non-specific low back pain (LBP) is influenced by, among other factors, patients' self-management abilities. Therefore, clinical guidelines recommend stimulation of self-management. Enhancing patients' self-management potentially can improve patients’ health outcomes and reduce future healthcare costs for non-specific LBP. Objectives: Which characteristics and health outcomes are associated with activation for self-management in patients with non-specific LBP? Design: Cross-sectional study. Method: Patients with non-specific LBP applying for primary care physiotherapy were asked to participate. Multivariable linear regression analysis was performed to analyze the multivariable relationship between activation for self-management (Patient Activation Measure, range 0–100) and a range of characteristics, e.g., age, gender, and health outcomes, e.g., self-efficacy, pain catastrophizing. Results: The median activation for self-management score of the patients with non-specific LBP (N = 208) was 63.10 (IQR = 19.30) points. The multivariable linear regression analysis revealed that higher self-efficacy scores (B = 0.54), female gender (B = 3.64), and a middle educational level compared with a high educational level (B = −5.47) were associated with better activation for self-management in patients with non-specific LBP. The goodness-of-fit of the model was 17.24% (R2 = 0.17). Conclusions: Patients with better activation for self-management had better self-efficacy, had a higher educational level, and were more often female. However, given the explained variance better understanding of the factors that influence the complex construct of self-management behaviour in patients who are not doing well might be needed to identify possible barriers to engage in self-management
The Physical Conditions for Massive Star Formation: Dust Continuum Maps and Modeling
Fifty-one dense cores associated with water masers were mapped at 350 micron.
These cores are very luminous, 10^3 < Lbol/Lsun < 10^6, indicative of the
formation of massive stars. Dust continuum contour maps and photometry are
presented for these sources. The spectral energy distributions and normalized
radial profiles of dust continuum emission were modeled for 31 sources using a
one-dimensional dust radiative transfer code, assuming a power law density
distribution in the envelope, n = n_f (r/r_f)^{-p}. The best fit density power
law exponent, p, ranged from 0.75 to 2.5 with = 1.8 +/- 0.4. The mean value
of p is comparable to that found in regions forming only low mass stars. The
mean p is incompatible with a logatropic sphere (p = 1), but other star
formation models cannot be ruled out. Different mass estimates are compared and
mean masses of gas and dust are reported within a half-power radius determined
from the dust emission and within a radius where the total density exceeds 10^4
cm^3. Evolutionary indicators commonly used for low mass star formation may
have some utility for regions forming massive stars. For comparison with
extragalactic star formation studies, the luminosity to dust mass ratio is
calculated for these sources with a method most parallel to that used in
studies of distant galaxies and is found to be similar to that seen in high
redshift starburst galaxies.Comment: 45 pages, 20 figures, accepted to ApJ Supplemen
Quantitative colorimetric-imaging analysis of nickel in iron meteorites
A quantitative analytical imaging approach for determining the nickel content of metallic meteorites is proposed. The approach uses a digital image of a series of standard solutions of the nickel-dimethylglyoxime coloured chelate and a meteorite sample solution subjected to the same treatment as the nickel standards for quantitation. The image is processed with suitable software to assign a colour-dependent numerical value (analytical signal) to each standard. Such a value is directly proportional to the analyte concentration, which facilitates construction of a calibration graph where the value for the unknown sample can be interpolated to calculate the nickel content of the meteorite. The results thus obtained were validated by comparison with the official, ISO-endorsed spectrophotometric method for nickel. The proposed method is fairly simple and inexpensive; in fact, it uses a commercially available digital camera as measuring instrument and the images it provides are processed with highly user-friendly public domain software (specifically, ImageJ, developed by the National Institutes of Health and freely available for download on the Internet). In a scenario dominated by increasingly sophisticated and expensive equipment, the proposed method provides a cost-effective alternative based on simple, robust hardware that is affordable and can be readily accessed worldwide. This can be especially advantageous for countries were available resources for analytical equipment investments are scant. The proposed method is essentially an adaptation of classical chemical analysis to current, straightforward, robust, cost-effective instrumentation. © 2010 Elsevier B.V. All rights reserved.Lahuerta Zamora, L.; Alemán López, P.; Antón Fos, G.; MartÃn Algarra, R.; Mellado Romero, AM.; MartÃnez Calatayud, J. (2011). Quantitative colorimetric-imaging analysis of nickel in iron meteorites. Talanta. 83:1575-1579. doi:10.1016/j.talanta.2010.11.058S157515798
How Well Do Randomized Trials Inform Decision Making: Systematic Review Using Comparative Effectiveness Research Measures on Acupuncture for Back Pain
Background: For Comparative Effectiveness Research (CER) there is a need to develop scales for appraisal of available clinical research. Aims were to 1) test the feasibility of applying the pragmatic-explanatory continuum indicator summary tool and the six CER defining characteristics of the Institute of Medicine to RCTs of acupuncture for treatment of low back pain, and 2) evaluate the extent to which the evidence from these RCTs is relevant to clinical and health policy decision making. Methods: We searched Medline, the AcuTrials™ Database to February 2011 and reference lists and included full-report randomized trials in English that compared needle acupuncture with a conventional treatment in adults with non-specific acute and/or chronic low back pain and restricted to those with ≥30 patients in the acupuncture group. Papers were evaluated by 5 raters. Principal Findings: From 119 abstracts, 44 full-text publications were screened and 10 trials (4,901 patients) were evaluated. Due to missing information and initial difficulties in operationalizing the scoring items, the first scoring revealed inter-rater and inter-item variance (intraclass correlations 0.02-0.60), which improved after consensus discussions to 0.20-1.00. The 10 trials were found to cover the efficacy-effectiveness continuum; those with more flexible acupuncture and no placebo control scored closer to effectiveness. Conclusion: Both instruments proved useful, but need further development. In addition, CONSORT guidelines for reporting pragmatic trials should be expanded. Most studies in this review already reflect the movement towards CER and similar approaches can be taken to evaluate comparative effectiveness relevance of RCTs for other treatments. © 2012 Witt et al.published_or_final_versio
Diurnal Rhythms Result in Significant Changes in the Cellular Protein Complement in the Cyanobacterium Cyanothece 51142
Cyanothece sp. ATCC 51142 is a diazotrophic cyanobacterium notable for its ability to perform oxygenic photosynthesis and dinitrogen fixation in the same single cell. Previous transcriptional analysis revealed that the existence of these incompatible cellular processes largely depends on tightly synchronized expression programs involving ∼30% of genes in the genome. To expand upon current knowledge, we have utilized sensitive proteomic approaches to examine the impact of diurnal rhythms on the protein complement in Cyanothece 51142. We found that 250 proteins accounting for ∼5% of the predicted ORFs from the Cyanothece 51142 genome and 20% of proteins detected under alternating light/dark conditions exhibited periodic oscillations in their abundances. Our results suggest that altered enzyme activities at different phases during the diurnal cycle can be attributed to changes in the abundance of related proteins and key compounds. The integration of global proteomics and transcriptomic data further revealed that post-transcriptional events are important for temporal regulation of processes such as photosynthesis in Cyanothece 51142. This analysis is the first comprehensive report on global quantitative proteomics in a unicellular diazotrophic cyanobacterium and uncovers novel findings about diurnal rhythms
Biological Interactions and Dynamics Science Theme Advisory Panel (BID-STAP)
This report contains the charge to the panel, the panel's discussions and panel recommendations
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Radionuclide detection by inductively coupled plasma mass spectrometry: A comparison of atomic and radiation detection method
Radionuclide detection by mass spectrometric techniques offers inherent advantages over conventional radiation detection methods. Since radionuclides decay at variable rates (half-lives) and via various nuclear transformations (i.e. emission of alpha, beta, and/or gamma radiation) their determination via radiation detection depends not only on decay systematics but also on detector technology. Radionuclide detection by direct atom measurement, however, is dependent only on technique sensitivity and is indifferent to decay mode. Evaluation of inductively coupled plasma mass spectrometry (ICP/MS) indicates this method to be superior conventional radiation detection techniques for many radionuclides. This work discusses factors which influence detection by both methods. Illustrative applications of ICP/MS to the ultra-trace determination of several radionuclides, including {sup 129}I, are presented. 20 refs., 6 figs., 1 tab
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