862 research outputs found
The impact of seawater saturation state and bicarbonate ion concentration on calcification by new recruits of two Atlantic corals
Author Posting. © The Author(s), 2010. 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 Coral Reefs 30 (2011): 321-328, doi:10.1007/s00338-010-0697-z.Rising concentrations of atmospheric CO2 are changing the carbonate chemistry of the
oceans, a process known as ocean acidification (OA). Absorption of this CO2 by the surface oceans
is increasing the amount of total dissolved inorganic carbon (DIC) and bicarbonate ion (HCO3
-)
available for marine calcification, yet is simultaneously lowering the seawater pH and carbonate
ion concentration ([CO3
2-]), and thus the saturation state of seawater with respect to aragonite
(Ωar). We investigated the relative importance of [HCO3
-] versus [CO3
2-] for early calcification by
new recruits (primary polyps settled from zooxanthellate larvae) of two tropical coral species,
Favia fragum and Porites astreoides. The polyps were reared over a range of Ωar values, which
were manipulated by both acid-addition at constant pCO2 (decreased total [HCO3
-] and [CO3
2-])
and by pCO2 elevation at constant alkalinity (increased [HCO3
-], decreased [CO3
2-]). Calcification
after two weeks was quantified by weighing the complete skeleton (corallite) accreted by each
polyp over the course of the experiment. Both species exhibited the same negative response to
decreasing [CO3
2-] whether Ωar was lowered by acid-addition or by pCO2 elevation - calcification
did not follow total DIC or [HCO3
-]. Nevertheless, the calcification response to decreasing [CO3
2-]
was non-linear. A statistically significant decrease in calcification was only detected between Ωar =
< 2.5 and Ωar = 1.1 – 1.5, where calcification of new recruits was reduced by 22 – 37 % per 1.0
decrease in Ωar. Our results differ from many previous studies that report a linear coral
calcification response to OA, and from those showing that calcification increases with increasing
[HCO3
-]. Clearly, the coral calcification response to OA is variable and complex. A deeper
understanding of the biomineralization mechanisms and environmental conditions underlying these
3
variable responses is needed to support informed predictions about future OA impacts on corals
and coral reefs.This study was supported by NSF award 0648157 (Cohen and McCorkle), NSF 1041106 (Cohen,
McCorkle), NSF 1041052 (de Putron), the VITA foundation (de Putron), WHOI Ocean Life
Institute (Cohen), PEI and EEB Departments at Princeton University, Bill and Anne Charrier, and
the Anthony B. Evnin, Dean’s Roundtable, and Edmund Hayes Sr. senior thesis funds (Dillon)
Boron isotope sensitivity to seawater pH change in a species of Neogoniolithon coralline red alga
The increase in atmospheric carbon dioxide (CO2) observed since the industrial revolution has reduced surface ocean pH by ∼0.1 pH units, with further change in the oceanic system predicted in the coming decades. Calcareous organisms can be negatively affected by extreme changes in seawater pH (pHsw) such as this due to the associated changes in the oceanic carbonate system. The boron isotopic composition (δ11B) of biogenic carbonates has been previously used to monitor pH at the calcification site (pHcf) in scleractinian corals, providing mechanistic insights into coral biomineralisation and the impact of variable pHsw on this process. Motivated by these investigations, this study examines the δ11B of the high-Mg calcite skeleton of the coralline red alga Neogoniolithon sp. to constrain pHcf, and investigates how this taxon’s pHcf is impacted by ocean acidification. δ11B was measured in multiple algal replicates (n = 4–5) cultured at four different pCO2 scenarios – averaging (±1σ) 409 (±6), 606 (±7), 903 (±12) and 2856 (±54) μatm, corresponding to average pHsw (±1σ) of 8.19 (±0.03), 8.05 (±0.06), 7.91 (±0.03) and 7.49 (±0.02) respectively. Results show that skeletal δ11B is elevated relative to the δ11B of seawater borate at all pHsw treatments by up to 18‰. Although substantial variability in δ11B exists between replicate samples cultured at a given pHsw (smallest range = 2.32‰ at pHsw 8.19, largest range = 6.08‰ at pHsw 7.91), strong correlations are identified between δ11B and pHsw (R2 = 0.72, p < 0.0001, n = 16) and between δ11B and B/Ca (R2 = 0.72, p < 0.0001, n = 16). Assuming that skeletal δ11B reflects pHcf as previously observed for scleractinian corals, the average pHcf across all experiments was 1.20 pH units (0.79 to 1.56) higher than pHsw, with the magnitude of this offset varying parabolically with decreasing pHsw, with a maximum difference between pHsw and pHcf at a pHsw of 7.91. Observed relationships between pHsw and calcification rate, and between pHsw and pHcf, suggest that coralline algae exhibit some resilience to moderate ocean acidification via increase of pHcf relative to pHsw in a similar manner to scleractinian corals. However, these results also indicate that pHcf cannot be sufficiently increased by algae exposed to a larger reduction in pHsw, adversely impacting calcification rates of coralline red algae
High frequency chest wall oscillation for asthma and chronic obstructive pulmonary disease exacerbations: a randomized sham-controlled clinical trial
<p>Abstract</p> <p>Background</p> <p>High frequency chest wall oscillation (HFCWO) is used for airway mucus clearance. The objective of this study was to evaluate the use of HFCWO early in the treatment of adults hospitalized for acute asthma or chronic obstructive pulmonary disease (COPD).</p> <p>Methods</p> <p>Randomized, multi-center, double-masked phase II clinical trial of active or sham treatment initiated within 24 hours of hospital admission for acute asthma or COPD at four academic medical centers. Patients received active or sham treatment for 15 minutes three times a day for four treatments. Medical management was standardized across groups. The primary outcomes were patient adherence to therapy after four treatments (minutes used/60 minutes prescribed) and satisfaction. Secondary outcomes included change in Borg dyspnea score (≥ 1 unit indicates a clinically significant change), spontaneously expectorated sputum volume, and forced expired volume in 1 second.</p> <p>Results</p> <p>Fifty-two participants were randomized to active (n = 25) or sham (n = 27) treatment. Patient adherence was similarly high in both groups (91% vs. 93%; p = 0.70). Patient satisfaction was also similarly high in both groups. After four treatments, a higher proportion of patients in the active treatment group had a clinically significant improvement in dyspnea (70.8% vs. 42.3%, p = 0.04). There were no significant differences in other secondary outcomes.</p> <p>Conclusions</p> <p>HFCWO is well tolerated in adults hospitalized for acute asthma or COPD and significantly improves dyspnea. The high levels of patient satisfaction in both treatment groups justify the need for sham controls when evaluating the use of HFCWO on patient-reported outcomes. Additional studies are needed to more fully evaluate the role of HFCWO in improving in-hospital and post-discharge outcomes in this population.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00181285">NCT00181285</a></p
Four patients with a history of acute exacerbations of COPD: implementing the CHEST/Canadian Thoracic Society guidelines for preventing exacerbations
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Improving outcomes for people with COPD by developing networks of general practices: evaluation of a quality improvement project in east London
BACKGROUND: Structured care for people with chronic obstructive pulmonary disease (COPD) can improve outcomes. Delivering care in a deprived ethnically diverse area can prove challenging. AIMS: Evaluation of a system change to enhance COPD care delivery in a primary care setting between 2010 and 2013 using observational data. METHODS: All 36 practices in one inner London primary care trust were grouped geographically into eight networks of 4-5 practices, each supported by a network manager, clerical staff and an educational budget. A multidisciplinary group, including a respiratory specialist and the community respiratory team, developed a 'care package' for COPD management, with financial incentives based on network achievements of clinical targets and supported case management and education. Monthly electronic dashboards enabled networks to track and improve performance. RESULTS: The size of network COPD registers increased by 10% in the first year. Between 2010 and 2013 completed care plans increased from 53 to 86.5%, pulmonary rehabilitation referrals rose from 45 to 70% and rates of flu immunisation from 81 to 83%, exceeding London and England figures. Hospital admissions decreased in Tower Hamlets from a historic high base. CONCLUSIONS: Investment of financial, organisational and educational resource into general practice networks was associated with clinically important improvements in COPD care in socially deprived, ethnically diverse communities. Key behaviour change included the following: collaborative working between practices driven by high-quality information to support performance review; shared financial incentives; and engagement between primary and secondary care clinicians
Qualitative thematic analysis of consent forms used in cancer genome sequencing
<p>Abstract</p> <p>Background</p> <p>Large-scale whole genome sequencing (WGS) studies promise to revolutionize cancer research by identifying targets for therapy and by discovering molecular biomarkers to aid early diagnosis, to better determine prognosis and to improve treatment response prediction. Such projects raise a number of ethical, legal, and social (ELS) issues that should be considered. In this study, we set out to discover how these issues are being handled across different jurisdictions.</p> <p>Methods</p> <p>We examined informed consent (IC) forms from 30 cancer genome sequencing studies to assess (1) stated purpose of sample collection, (2) scope of consent requested, (3) data sharing protocols (4) privacy protection measures, (5) described risks of participation, (6) subject re-contacting, and (7) protocol for withdrawal.</p> <p>Results</p> <p>There is a high degree of similarity in how cancer researchers engaged in WGS are protecting participant privacy. We observed a strong trend towards both using samples for additional, unspecified research and sharing data with other investigators. IC forms were varied in terms of how they discussed re-contacting participants, returning results and facilitating participant withdrawal. Contrary to expectation, there were no consistent trends that emerged over the eight year period from which forms were collected.</p> <p>Conclusion</p> <p>Examining IC forms from WGS studies elucidates how investigators are handling ELS challenges posed by this research. This information is important for ensuring that while the public benefits of research are maximized, the rights of participants are also being appropriately respected.</p
Do supervised weekly exercise programs maintain functional exercise capacity and quality of life, twelve months after pulmonary rehabilitation in COPD?
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Survival analysis modeling with hidden censoring
There are well-established survival analysis methodologies for data sets that are complete, with accurate information on censoring. But what if they are not complete? In this article we consider how to analyze cases where “hidden censoring” occurs, where individuals have effectively left the study but the hospital is unaware of this. We develop a new Markov chain-based methodology for generating survival curves and hazard functions, and demonstrate this using a breast cancer data set from the Kurdistan region of Iraq
Repercussões tardias de um programa de reabilitação pulmonar sobre os índices de ansiedade, depressão, qualidade de vida e desempenho físico em portadores de DPOC
Perivascular epitheloid cell tumour (PEComa) of the retroperitoneum – a rare tumor with uncertain malignant behaviour: a case report
<p>Abstract</p> <p>Introduction</p> <p>Perivascular epitheloid cell tumours are rare mesenchymal neoplasms characterized by a proliferation of perivascular cells with an epitheloid phenotype and expression of myomelanocytic markers.</p> <p>Case presentation</p> <p>Here we present the case of a cystic perivascular epitheloid cell tumour of the retroperitoneum associated with multifocal lung lesions. A 27-year-old woman underwent laparotomy to remove a 10 × 6 × 4 cm sized retroperitoneal mass. The resected specimen was subjected to frozen and permanent histological sections with conventional and immunohistochemical stains, including antibodies against HMB45. The tumour displayed the typical morphological and immunohistochemical features of a perivascular epitheloid cell tumour. Focal necrosis and a proliferative index of 10% suggested a malignant potential. Moreover, postoperative computed tomography scans demonstrated multiple lung lesions, which were radiologically interpreted as being most likely compatible with lymphangioleiomyomatosis.</p> <p>Conclusion</p> <p>Since lymphangioleiomyomatosis, an otherwise benign condition, belongs to the family of perivascular epitheloid cell tumours, it cannot be excluded that the lung lesions in this case in fact represent metastases from the retroperitoneal perivascular epitheloid cell tumour rather than independent neoplasms. More experience with this new and unusual tumour entity is clearly needed in order to define reliable criteria for benign or malignant behaviour.</p
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