Occupational Risk Factors in Chronic Obstructive Pulmonary Disease

Introduction: Chronic obstructive pulmonary disease (COPD) causes increased disability and mortality in the U.S. population. Approximately 15% of cases of COPD can be attributed to occupational exposure. There are gaps in the knowledge of the relationships between occupational exposure and COPD and further investigation can provide information helpful in improving COPD preventive strategies in the workplace. The objective of this project was to assess COPD prevalence in population based studies and characterize the relationship between COPD and occupational exposure.;Methods/Results: Three separate U.S. population-based cross-sectional studies of COPD were conducted. In the first study, a COPD job exposure matrix (JEM) was created to characterize exposure of working adults to vapors-gas, dust, and fumes (VGDF). Next the JEM was applied to investigate the association between occupational exposure and COPD using data from a large population-based study where good quality spirometry and questionnaire data on chronic bronchitis, wheeze, and severity and duration of exposure to VGDF were collected. In the second study, COPD prevalence was estimated for the older U.S. population (40--79 years of age) over two periods, years 1988--1994 and years 2007--2010. The results show that COPD prevalence is declining. However, COPD still remains a significant problem. In the third study, prevalence estimates of COPD for the U.S. working population by major occupational groups were estimated. Higher odds of COPD were found among certain occupation groups.;Conclusions: The findings from this study provide perspective on contemporary trends in COPD prevalence and confirm that COPD remains a substantial problem in the U.S. population and more specifically in the working population. Exposure to VGDF continues to be associated with COPD as does smoking. This research expands the evidence on the association of COPD with VGDF exposure and certain occupation groups highlighting current trends in the U.S. occupations at risk for COPD. Understanding these evolving trends in COPD prevalence helps to develop strategies and interventions to further reduce exposure to VGDF and tobacco smoking to reduce the burden of COPD

Clinical and FDG-PET/CT Suspicion of Malignant Disease:Is Biopsy Confirmation Still Necessary?

Background: Biopsy of F-18-fluoro-2-deoxy-D-glucose (FDG)-avid lesions suspected for malignancy remains an invasive procedure associated with a variety of risks. It is still unclear if the positive predictive value (PPV) of positron emission tomography (PET)/computed tomography (CT) is sufficiently high to avoid tissue sampling. Therefore, the purpose of this study was to determine the PPV of F-18-FDG-PET/CT for malignancy in patients with a clinical suspicion of active malignant disease. Methods: This single-center retrospective study included 83 patients who had undergone FDG-PET/CT within 60 days before CT- or ultrasonography-guided tissue sampling and whose request form for CT- or US-guided tissue sampling requested mutation analyses. The latter implies a high clinical suspicion of active malignant disease. The nature of each biopsied lesion was determined based on the results of the pathological analysis and/or clinical and imaging follow-up of at least 12 months. Results: In total, eighty-eight FDG-avid lesions were biopsied. The PPV of FDG-PET/CT for malignancy was 98.9% (95% CI: 93.8-99.8%). For patients with an oncological history, the PPV was 98.7% (95% CI: 92.9-99.8%), and for patients with no oncological history, the PPV was 100% (95% CI: 74.1-100.0%). There was no significant difference between the PPV of the group with and without an oncological history (p = 0.71). In two cases, an unsuspected malignancy was diagnosed. Conclusion: Although the PPV of FDG-PET/CT for malignancy in patients with a clinical suspicion of active malignant disease is high, biopsy remains recommended to avoid inappropriate patient management due the non-negligible chance of dealing with FDG-avid benign disease or unexpected malignancies

Aggregates explain the high clay retention of small constructed wetlands : a micromorphological study

Earlier studies have shown that small constructed wetlands are more efficient as sedimentation basins for eroded soil material than expected from calculations based on detention time. It has been suggested that this is caused by sedimentation of aggregates. The present microscopic study of thin sections made from undisturbed samples of wetland sediments confirmed that the fine silt and clay fractions are present in aggregated form. Aggregates from the wetland sediments had the same mineralogical composition as those from the corresponding arable land, but were more rounded, indicating erosion during transport. To prevent breakdown of aggregates, wetlands should therefore be constructed as close to the source of erosion as possible. A correct prediction of particle retention in constructed wetlands has to take into account the presence of aggregates. Textural analysis methods, which require clay dispersion pre-treatment, are not suitable for the calculation of the retention of fine silt and clay

Hybrid quantum computing with ancillas

In the quest to build a practical quantum computer, it is important to use efficient schemes for enacting the elementary quantum operations from which quantum computer programs are constructed. The opposing requirements of well-protected quantum data and fast quantum operations must be balanced to maintain the integrity of the quantum information throughout the computation. One important approach to quantum operations is to use an extra quantum system - an ancilla - to interact with the quantum data register. Ancillas can mediate interactions between separated quantum registers, and by using fresh ancillas for each quantum operation, data integrity can be preserved for longer. This review provides an overview of the basic concepts of the gate model quantum computer architecture, including the different possible forms of information encodings - from base two up to continuous variables - and a more detailed description of how the main types of ancilla-mediated quantum operations provide efficient quantum gates.Comment: Review paper. An introduction to quantum computation with qudits and continuous variables, and a review of ancilla-based gate method

A 4-D dataset for validation of crystal growth in a complex three-phase material, ice cream

Four dimensional (4D, or 3D plus time) X-ray tomographic imaging of phase changes in materials is quickly becoming an accepted tool for quantifying the development of microstructures to both inform and validate models. However, most of the systems studied have been relatively simple binary compositions with only two phases. In this study we present a quantitative dataset of the phase evolution in a complex three-phase material, ice cream. The microstructure of ice cream is an important parameter in terms of sensorial perception, and therefore quantification and modelling of the evolution of the microstructure with time and temperature is key to understanding its fabrication and storage. The microstructure consists of three phases, air cells, ice crystals, and unfrozen matrix. We perform in situ synchrotron X-ray imaging of ice cream samples using in-line phase contrast tomography, housed within a purpose built cold-stage (-40 to +20oC) with finely controlled variation in specimen temperature. The size and distribution of ice crystals and air cells during programmed temperature cycling are determined using 3D quantification. The microstructural evolution of three-phase materials has many other important applications ranging from biological to structural and functional material, hence this dataset can act as a validation case for numerical investigations on faceted and non-faceted crystal growth in a range of materials

Higher biomass accumulation by increasing phosphoribosylpyrophosphate synthetase activity in Arabidopsis thaliana and Nicotiana tabacum

Plants are able to produce all the organic compounds required for development and growth. As developmental processes and metabolic pathways use a common resource pool, the tight regulation of the distribution of metabolites between growth, production of defence compounds and storage products can be assumed. A transgenic approach was used to investigate the importance of supplying the key intermediate phosphoribosylpyrophosphate (PRPP) for plant growth and biomass accumulation in the model plant Arabidopsis thaliana and in Nicotiana tabacum. For this purpose, the Ashbya gossypii genes coding for either PRPP synthetase (PRS) or a mutated variant of the same gene were over-expressed under the control of a constitutive promoter. It was shown that increased PRS activity in A. thaliana or N. tabacum leads to a substantial increase in biomass accumulation under different standardized growth conditions. Growth enhancement was accompanied by significant changes in the amount of sugars and other metabolites. This study provides evidence that the supply of PRPP co-limits growth rates, and has obvious implications for biotechnological strategies aiming to increase plant biomass as an alternative renewable energy source

Ca(2+ )binding to complement-type repeat domains 5 and 6 from the low-density lipoprotein receptor-related protein

BACKGROUND: The binding of ligands to clusters of complement-type repeat (CR)-domains in proteins of the low-density lipoprotein receptor (LDLR) family is dependent on Ca(2+ )ions. One reason for this cation requirement was identified from the crystal structure data for a CR-domain from the prototypic LDLR, which showed the burial of a Ca(2+ )ion as a necessity for correct folding and stabilization of this protein module. Additional Ca(2+ )binding data to other CR-domains from both LDLR and the LDLR-related protein (LRP) have suggested the presence of a conserved Ca(2+ )cage within CR-domains from this family of receptors that function in endocytosis and signalling. RESULTS: We have previously described the binding of several ligands to a fragment comprising the fifth and the sixth CR-domain (CR56) from LRP, as well as qualitatively described the binding of Ca(2+ )ions to this CR-domain pair. In the present study we have applied the rate dialysis method to measure the affinity for Ca(2+), and show that CR56 binds 2 Ca(2+ )ions with an average affinity of K(D )= 10.6 microM, and there is no indication of additional Ca(2+ )binding sites within this receptor fragment. CONCLUSIONS: Both CR-domains of CR56 bind a single Ca(2+ )ion with an affinity of 10.6 microM within the range of affinities demonstrated for several other CR-domains