1,233 research outputs found
Seasonal and diurnal variations of particulate nitrate and organic matter at the IfT research station Melpitz
Ammonium nitrate and several organic compounds such as dicarboxylic acids (e.g. succinic acid, glutaric acid), some Polycyclic Aromatic Hydrocarbon (PAHs) or some n-alkanes are semi-volatile. The transition of these compounds between the gas and particulate phase may significantly change the aerosol particles radiative properties, the heterogeneous chemical properties, and, naturally, the total particulate mass concentration. To better assess these time-dependent effects, three intensive field experiments were conducted in 2008â2009 at the Central European EMEP research station Melpitz (Germany) using an Aerodyne Aerosol Mass Spectrometer (AMS). Data from all seasons highlight organic matter as being the most important particulate fraction of PM1 in summer (59%) while in winter, the nitrate fraction was more prevalent (34.4%). The diurnal variation of nitrate always showed the lowest concentration during the day while its concentration increased during the night. This night increase of nitrate concentration was higher in winter (ÎNO3â = 3.6 ÎŒg mâ3) than in summer (ÎNO3â = 0.7 ÎŒg mâ3). The variation in particulate nitrate was inherently linked to the gas-to-particle-phase equilibrium of ammonium nitrate and the dynamics of the atmosphere during day. The results of this study suggest that during summer nights, the condensation of HNO3 and NH3 on pre-existing particles represents the most prevalent source of nitrate, whereas during winter, nighttime chemistry is the predominant source of nitrate. During the summer 2008's campaign, a clear diurnal evolution in the oxidation state of the organic matter became evident (Organic Mass to Organic Carbon ratio (OM/OC) ranging from 1.65 during night to 1.80 during day and carbon oxidation state (OSc) from â0.66 to â0.4), which could be correlated to hydroxyl radical (OH) and ozone concentrations, indicating a photochemical transformation process. In summer, the organic particulate matter seemed to be heavily influenced by regional secondary formation and transformation processes, facilitated by photochemical production processes as well as a diurnal cycling of the substances between the gas and particulate phase. In winter, these processes were obviously less pronounced (OM/OC ranging from 1.60 to 1.67 and OSc from â0.8 to â0.7), so that organic matter apparently originated mainly from aged particles and long range transport
What can we learn from Xâray fluorescence core scanning data? A paleoâmonsoon case study
Xâray fluorescence (XRF) core scanning of marine and lake sediments has been extensively used to study changes in past environmental and climatic processes over a range of timescales. The interpretation of XRFâderived element ratios in paleoclimatic and paleoceanographic studies primarily considers differences in the relative abundances of particular elements. Here we present new XRF core scanning data from two long sediment cores in the Andaman Sea in the northern Indian Ocean and show that sea level related processes influence terrigenous inputs based proxies such as Ti/Ca, Fe/Ca, and elemental concentrations of the transition metals (e.g. Mn). Zr/Rb ratios are mainly a function of changes in median grain size of lithogenic particles and often covary with changes in Ca concentrations that reflect changes in biogenic calcium carbonate production. This suggests that a common process (i.e. sea level) influences both records. The interpretation of lighter element data (e.g. Si and Al) based on low XRF counts is complicated as variations in mean grain size and water content result in systematic artifacts and signal intensities not related to the Al or Si content of the sediments. This highlights the need for calibration of XRF core scanning data based on discrete sample analyses and careful examination of sediment properties such as porosity/water content for reliably disentangling environmental signals from other physical properties. In the case of the Andaman Sea, reliable extraction of a monsoon signal will require accounting for the sea level influence on the XRF data
Improving Guideline Adherence in Urology
CONTEXT: Clinical practice guidelines (CPGs) distil an evidence base into recommendations. CPG adherence is associated with better patient outcomes. However, preparation and dissemination of CPGs are a costly task involving multiple skilled personnel. Furthermore, dissemination alone does not ensure CPG adherence. Reasons for nonadherence are often complex, but understanding practice variations and reasons for nonadherence is key to improving CPG adherence and harmonising clinically appropriate and cost-effective care. OBJECTIVE: To overview approaches to improving guideline adherence, to provide urology-specific examples of knowledge-practice gaps, and to highlight potential solutions informed by implementation science. EVIDENCE ACQUISITION: Three common approaches to implementation science (the Knowledge-To-Action framework, the Consolidated Framework for Implementation Research, and the Behaviour Change Wheel), are summarised. EVIDENCE SYNTHESIS: Three implementation problems in urology are illustrated: underuse of single instillation of intravesical chemotherapy in non-muscle-invasive bladder cancer, overuse of androgen deprivation therapy in localised prostate cancer, and guideline-discordant imaging in prostate cancer. Research using implementation science approaches to address these implementation problems is discussed. CONCLUSIONS: Urologists, patients, health care providers, funders, and other key stakeholders must commit to reliably capturing and reporting data on patient outcomes, practice variations, guideline adherence, and the impact of adherence on outcomes. Leverage of implementation science frameworks is a sound next step towards improving guideline adherence and the associated benefits of evidence-based care. PATIENT SUMMARY: Clinical practice guideline documents are created by expert panels. These documents provide overviews of the evidence for the tests and treatments used in patient care. They also provide recommendations and it is expected that in most circumstances clinicians will follow these recommendations. Sometimes, health care professionals cannot or do not follow these recommendations and it is not always clear why. In this review article we look at some examples of research approaches to addressing this problem of nonadherence and we provide some examples specific to urology
PAGA: graph abstraction reconciles clustering with trajectory inference through a topology preserving map of single cells.
Single-cell RNA-seq quantifies biological heterogeneity across both discrete cell types and continuous cell transitions. Partition-based graph abstraction (PAGA) provides an interpretable graph-like map of the arising data manifold, based on estimating connectivity of manifold partitions ( https://github.com/theislab/paga ). PAGA maps preserve the global topology of data, allow analyzing data at different resolutions, and result in much higher computational efficiency of the typical exploratory data analysis workflow. We demonstrate the method by inferring structure-rich cell maps with consistent topology across four hematopoietic datasets, adult planaria and the zebrafish embryo and benchmark computational performance on one million neurons.Wellcome Trust, MRC, CRUK, Bloodwise, Swedish Research Council, Helmholtz Association, German Center for Cardiovascular Research, German Research Foundatio
Dissipative Field Theory with Caldeira-Leggett Method and its Application to Disoriented Chiral Condensation
The effective field theory including the dissipative effect is developed
based on the Caldeira-Leggett theory at the classical level. After the
integration of the small field fluctuations considered as the field radiation,
the integro-differential field equation is given and shown to include the
dissipative effects. In that derivation, special cares should be taken for the
boundary condition of the integration. Application to the linear sigma model is
given, and the decay process of the chiral condensate is calculated with it,
both analytically in the linear approximation and numerically. With these
results, we discuss the stability of chiral condensates within the quenched
approximation.Comment: 16pages, ReV-Te
8-hydroxyquinoline-2-carboxylic acid as possible molybdophore: A multi-technique approach to define its chemical speciation, coordination and sequestering ability in aqueous solution
8-hydroxyquinoline-2-carboxylic acid (8-HQA) has been found in high concentrations (0.5â5.0 mmol·dmâ3) in the gut of Noctuid larvae (and in a few other lepidopterans), in which it is proposed to act as a siderophore. Since it is known that many natural siderophores are also involved in the uptake and metabolism of other essential elements than iron, this study reports some results on the investigation of 8-HQA interactions with molybdate (MoO42â, i.e., the main molybdenum form in aqueous environments), in order to understand the possible role of this ligand as molybdophore. A multi-technique approach has been adopted, in order to derive a comprehensive set of information necessary to assess the chemical speciation of the 8-HQA/MoO42â system, as well as the coordination behavior and the sequestering ability of 8-HQA towards molybdate. Chemical speciation studies have been performed in KCl(aq) at I = 0.2 mol·dmâ3 and T = 298.15 K by ISE-H+ (glass electrode) potentiometric and UV/Vis spectrophotometric titrations. CV (Cyclic Voltammetry), DP-ASV (Differential Pulse-Anodic Stripping Voltammetry), ESI-MS experiments and quantum mechanical calculations have been also performed to derive information about the nature and possible structure of species formed. These results are also compared with those reported for the 8-HQA/Fe3+ system in terms of chemical speciation and sequestering ability of 8HQA
Changing current practice in urology: Improving guideline development and implementation through stakeholder engagement
Effective stakeholder integration for guideline development should improve outcomes and adherence to clinical practice guidelines
Variability in organ-specific EGFR mutational spectra in tumour epithelium and stroma may be the biological basis for differential responses to tyrosine kinase inhibitors
Organ-specific differences in epidermal growth factor receptor (EGFR) mutational spectra and frequencies were found in lung cancer and sporadic and BRCA1/2-related breast cancers. Additionally, we found a high frequency of EGFR mutations in the tumour stroma of these invasive breast carcinomas. Those organ-specific mutational spectra and potential targets in the cancer-associated stroma might influence the efficacy of TKI therapy
Schottky mass measurements of heavy neutron-rich nuclides in the element range 70\leZ \le79 at the ESR
Storage-ring mass spectrometry was applied to neutron-rich Au
projectile fragments. Masses of Lu, Hf, Ta,
W, and Re nuclei were measured for the first time. The
uncertainty of previously known masses of W and Os nuclei
was improved. Observed irregularities on the smooth two-neutron separation
energies for Hf and W isotopes are linked to the collectivity phenomena in the
corresponding nuclei.Comment: 10 pages, 9 figures, 2 table
A novel mutation in the tyrosine kinase domain of ERBB2 in hepatocellular carcinoma
BACKGROUND: Several studies showed that gain-of-function somatic mutations affecting the catalytic domain of EGFR in non-small cell lung carcinomas were associated with response to gefitinib and erlotinib, both EGFR-tyrosine kinase inhibitors. In addition, 4% of non-small cell lung carcinomas were shown to have ERBB2 mutations in the kinase domain. In our study, we sought to determine if similar respective gain-of-function EGFR and ERBB2 mutations were present in hepatoma and/or biliary cancers. METHODS: We extracted genomic DNA from 40 hepatoma (18) and biliary cancers (22) samples, and 44 adenocarcinomas of the lung, this latter as a positive control for mutation detection. We subjected those samples to PCR-based semi-automated double stranded nucleotide sequencing targeting exons 18â21 of EGFR and ERBB2. All samples were tested against matched normal DNA. RESULTS: We found 11% of hepatoma, but no biliary cancers, harbored a novel ERBB2 H878Y mutation in the activating domain. CONCLUSION: These newly described mutations may play a role in predicting response to EGFR-targeted therapy in hepatoma and their role should be explored in prospective studies
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