275 research outputs found

    Negligible influence of livestock contaminants and sampling system on ammonia measurements with cavity ring-down spectroscopy

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    Emission of ammonia (NH3) is a ubiquitous problem due to the adverse effects of NH3 on the environment and human health. The agricultural sector accounts for nearly all NH3 emissions in Europe. Hence, technologies for the abatement of NH3 emissions from this sector have been in strong demand in recent years. In order to document emissions and evaluate abatement technologies, there is a strong need for reliable NH3 measurement methods. Photoacoustic spectroscopy (PAS) is often used to measure NH3 concentrations, but recent research shows interference from compounds typically present in livestock production and during agricultural activities. In this work, the performance of cavity ring-down spectroscopy (CRDS) from Picarro, as an alternative to PAS, has been tested with respect to method validation under laboratory and field conditions. Potential interferences of 10 volatile organic compounds (VOCs) on CRDS NH3 measurement were tested with simultaneous VOC analysis performed by proton-transfer-reaction mass spectrometry (PTR-MS). Both laboratory and field calibrations show excellent linearity over a large dynamic range of NH3 concentrations. The analyzer shows a small humidity effect of up to a few&thinsp;ppb in the extreme case of a nearly water-saturated air stream. Apart from the negligible humidity dependency, no interferences of the tested VOCs were observed. Overall, the CRDS system performs satisfactory and is well suited for measurements of NH3 emissions from livestock production.</p

    Soil methane sink capacity response to a long-term wildfire chronosequence in Northern Sweden

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    Boreal forests occupy nearly one fifth of the terrestrial land surface and are recognised as globally important regulators of carbon (C) cycling and greenhouse gas emissions. Carbon sequestration processes in these forests include assimilation of CO2 into biomass and subsequently into soil organic matter, and soil microbial oxidation of methane (CH4). In this study we explored how ecosystem retrogression, which drives vegetation change, regulates the important process of soil CH4 oxidation in boreal forests. We measured soil CH4 oxidation processes on a group of 30 forested islands in northern Sweden differing greatly in fire history, and collectively representing a retrogressive chronosequence, spanning 5000 years. Across these islands the build-up of soil organic matter was observed to increase with time since fire disturbance, with a significant correlation between greater humus depth and increased net soil CH4 oxidation rates. We suggest that this increase in net CH4 oxidation rates, in the absence of disturbance, results as deeper humus stores accumulate and provide niches for methanotrophs to thrive. By using this gradient we have discovered important regulatory controls on the stability of soil CH4 oxidation processes that could not have not been explored through shorter-term experiments. Our findings indicate that in the absence of human interventions such as fire suppression, and with increased wildfire frequency, the globally important boreal CH4 sink could be diminished

    Quercetin enhances 5-fluorouracil-induced apoptosis in MSI colorectal cancer cells through p53 modulation

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    Purpose: Colorectal tumors (CRC) with microsatellite instability (MSI) show resistance to chemotherapy with 5-fluorouracil (5-FU), the most widely used pharmacological drug for CRC treatment. The aims of this study were to test the ability of quercetin (Q) and luteolin (L) to increase sensitivity of MSI CRC cells to 5-FU and characterize the dependence of the effects on cells´ p53 status. Methods: Two MSI human CRC derived cell lines were used, CO115 wild-type (wt) for p53 and HCT15 that harbors a p53 mutation. Apoptosis induction in these cells by 5-FU, Q and L alone and in combinations were evaluated by TUNEL and western. The dependence on p53 of the effects was confirmed by small interference RNA (siRNA) in CO115 cells and in MSI HCT116 wt and p53 knockout cells. Results: CO115 p53-wt cells are more sensitive to 5-FU than the p53 mutated HCT15. The combination treatment of 5-FU with L and Q increased apoptosis with a significant effect for Q in CO115. Both flavonoids increased p53 expression in both cell lines, an effect particularly remarkable for Q. The significant apoptotic enhancement in CO115 incubated with Q plus 5-FU involved the activation of the apoptotic mitochondrial pathway. Importantly, knockdown of p53 by siRNA in CO115 cells and p53 knockout in HCT116 cells totally abrogated apoptosis induction, demonstrating the dependence of the effect on p53 modulation by Q. Conclusion: This study suggests the potential applicability of these phytochemicals for enhancement 5-FU efficiency in MSI CRC therapy, especially Q in p53 wt tumors.CPRX was supported by the Foundation for Science and Technology (FCT), Portugal, through the grant SFRH/BD/27524/2006 and the work was supported by the FCT research grant PTDC/AGR-AAM/70418/2006

    Do Basic Psychomotor Skills Transfer Between Different Image-based Procedures?

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    Background - Surgical techniques that draw from multiple types of image-based procedures (IBP) are increasing, such as Natural Orifice Transluminal Endoscopic Surgery, fusing laparoscopy and flexible endoscopy. However, little is known about the relation between psychomotor skills for performing different types of IBP. For example, do basic psychomotor colonoscopy and laparoscopy skills interact? Methods - Following a cross-over study design, 29 naïve endoscopists were trained on the Simbionix GI Mentor and the SimSurgery SEP simulators. Group C (n = 15) commenced with a laparoscopy session, followed by four colonoscopy sessions and a second laparoscopy session. Group L (n = 14) started with a colonoscopy session, followed by four laparoscopy sessions and a second colonoscopy session. Results - No significant differences were found between the performances of group L and group C in their first training sessions on either technique. With additional colonoscopy training, group C outperformed group L in the second laparoscopy training session on the camera navigation task. Conclusions - Overall, training in the basic colonoscopy tasks does not affect performance of basic laparoscopy tasks (and vice versa). However, to limited extent, training of basic psychomotor skills for colonoscopy do appear to contribute to the performance of angled laparoscope navigation tasks. Thus, training and assessment of IBP typespecific skills should focus on each type of tasks independently. Future research should further investigate the influence of psychometric abilities on the performance of IBP and the transfer of skills for physicians who are experienced in one IBP type and would like to become proficient in another type of IBP.Industrial DesignIndustrial Design Engineerin

    Effect of an exercise training intervention with resistance bands on blood cell counts during chemotherapy for lung cancer: a pilot randomized controlled trial

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    PURPOSE: Chemotherapy for lung cancer can have a detrimental effect on white blood cell (WBC) and red blood cell (RBC) counts. Physical exercise may have a role in improving WBCs and RBCs, although few studies have examined cancer patients receiving adjuvant therapies. The purpose of this pilot trial was to examine the effects of an exercise intervention utilizing resistance bands on WBCs and RBCs in lung cancer patients receiving curative intent chemotherapy. METHODS: A sample of lung cancer patients scheduled for curative intent chemotherapy was randomly assigned to the exercise intervention (EX) condition or usual care (UC) condition. The EX condition participated in a three times weekly exercise program using resistance bands for the duration of chemotherapy. RESULTS: A total of 14 lung cancer patients completed the trial. EX condition participants completed 79% of planned exercise sessions. The EX condition was able to maintain WBCs over the course of the intervention compared to declines in the UC condition (p = .008; d = 1.68). There were no significant differences in change scores in RBCs. CONCLUSIONS: Exercise with resistance bands may help attenuate declines in WBCs in lung cancer patients receiving curative intent chemotherapy. Larger trials are warranted to validate these findings. Ultimately these findings could be informative for the development of supportive care strategies for lung cancer patients receiving chemotherapy. TRIAL REGISTRATION: Clinical Trials Registration #: NCT01130714

    Relationships Between Cardiorespiratory Fitness, Physical Activity, and Psychosocial Variables in Overweight and Obese Breast Cancer Survivors

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    # The Author(s) 2010. This article is published with open access at Springerlink.com Background Breast cancer survivors not only experience distressing physical symptoms associated with treatments, but also are faced with psychosocial challenges. Despite growing scientific evidence that physical activity (PA) may mitigate psychosocial distress experienced by women treated for breast cancer, the literature is equivocal. Purpose This study investigated the relationships between cardiorespiratory fitness (CRF), PA, and psychosocial factors in breast cancer survivors. Method Data involving overweight or obese breast cancer survivors (N=260) were examined. CRF was determined by a submaximal graded exercise test. PA, depressive symptoms, total fatigue, and global self-esteem were assessed with selfreport measures. Pearson&apos;s correlations were conducted to determine associations among CRF, PA, depressive symptoms, total fatigue, and global self-esteem. Multiple regression models, with age and body mass index as covariates, were performed using continuous levels for CRF and PA. Results Bivariate correlations suggested that CRF and PA were unrelated to the psychosocial variables. One of the regression models identified a marginally significant (P=0.06) inverse association between depressive symptoms and PA. Conclusion CRF and PA were not associated with psychosocial factors in this sample of breast cancer survivors. However

    Delayed referral to specialist centre increases morbidity in patients with bile duct injury (BDI) after laparoscopic cholecystectomy (LC)

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    Background: There is still a debate regarding the optimal management of bile duct injury following cholecystectomy. Our aim was to ascertain if delayed referral influenced clinical outcomes for patients with BDI treated in our institution. Materials and methods: We interrogated a prospectively maintained database, including all patients with BDI (Bismuth and Strasberg classifications) post LC managed in our unit from 2000-2014. Referrals were arbitrarily defined as early (&lt;96 hours from the injury) and delayed (&gt;96 hours). Results: 68 patients with BDI were managed. Patient demographics, referral time, level of injury and morbidity data was collected. 50 patients (77%) required a surgical bile duct reconstruction. The Early referral Group included 33 patients (52.4%) and Delayed referral group 30 (47.6%). The patients referred late had a significantly high incidence of right hepatic artery injury (23% vs. 3%) and the overall number of complications (0.0001). The average number of surgical interventions (2.5 vs 1.8, p&lt;0.05) and invasive procedures (4 vs. 2.5, p&lt; 0.05) per patient was high in the late referral group. There was significant difference in the interval between BDI-to-reconstruction (median 3 vs. median 88 days, p&lt; 0.05) and referral-to-hospital discharge (median 9 vs. median days 59, p&lt; 0.05). On multivariate analysis only delayed referral (OR 7.58, 95% CI 2.1-26.6) and Strasberg-E injuries (OR 4.86, 95% CI 1.1-20.9) were significant. Conclusion: A late referral was associated with a higher incidence of post-treatment complications, greater need for invasive procedures and a longer recovery period. These observations support the need for early patient transfer to a tertiary institution following BDI
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