Direct steam generation in parabolic trough collectors

Existing commercial parabolic trough power plants use thermal oil as a heat transfer fluid, with working temperatures in the region of 400ºC. In order to achieve more efficient generating systems, a second generation of parabolic troughs that operate at temperatures higher than 400ºC is being developed. One possibility, Abengoa Solar is assessing, it is the use of direct steam generation (DSG) inside parabolic troughs in order to achieve higher temperatures; the first stage heating up to 450 ºC and the second stage heating up to 550 ºC. There is, however, a certain degree of complexity in the use of DSG technology that has resulted in it not yet being utilized in commercial plant designs. Due to the presence of saturated steam inside the parallel loops the required control system is more complex, particularly during transitory periods of radiation. Also the higher operating pressures and temperatures in the solar field mean that the receiver tubes and interconnections between collectors are very critical components. For this reason, typical systems utilize an intermediate fluid for energy transfer. In order to overcome these challenges, Abengoa Solar has built a demonstration plant of 8 MWht. The plant is composed of an evaporator field with three parallel loops and a superheater field with two loops in order to work at 85 bar and 450ºC. The demonstration plant has been operated and evaluated for one year. During this test period, the following have been evaluated and validated: An innovative control strategy system that guarantees the stability of the plant even under transient conditions. Receiver tube design able to achieve 450ºC, analyzing the mechanical behavior, optical performance, and heat losses. Different configurations of interconnections between collectors with ball joints and flexible rotation joints. A theoretical model has been developed for commercial scale DSG plants and validated with experimental data obtained from the demonstration plant

Client satisfaction and experience of telemedicine and home use of mifepristone and misoprostol for abortion up to 10 weeks' gestation at British Pregnancy Advisory Service: A cross-sectional evaluation.

OBJECTIVE: Evaluate satisfaction and experience with telemedicine consultation and home use of mifepristone and misoprostol for abortion to 10 weeks' gestation. STUDY DESIGN: Cross-sectional evaluation of British Pregnancy Advisory Service (BPAS) clients who used mifepristone and misoprostol at home from 11 May to 10 July 2020. We sent a text message with a link to a web-survey 2 to 3 weeks postabortion. Questions assessed satisfaction and experiences with a service model including telephone consultation and provision of medicines by mail or collection from the clinic. We used bivariate and multivariate regression to explore associations between client characteristics and outcomes. Our primary outcomes were overall satisfaction (5-point Likert scale) and reported contact with a health care provider. RESULTS: A total of 1,333 clients participated. Respondents described home use of medications as "straightforward" (75.8%) and most were "very satisfied" (78.3%) or "satisfied" (18.6%) overall. Being "very satisfied" was associated with parity (aOR 1.53, 95% CI 1.09-2.14) and pain control satisfaction (aOR 2.22, 95% CI 1.44-3.44). Health care provider contact was reported by 14.7%; mainly to BPAS' telephone aftercare service (76.8%). Dissatisfaction with pain control (aOR 3.62, 95% CI 1.79-7.29) and waiting >1 week to use mifepristone (aOR3.71, 95% CI 1.48-9.28) were associated with health care provider contact. If needed in the future, most would prefer consultation by phone (74.3%) and home use of mifepristone and misoprostol (77.8%). CONCLUSIONS: Satisfaction with telemedicine and home use of mifepristone and misoprostol is high. Most clients do not need health care provider support when administering medicines at home or post abortion

Beyond national narratives? : centenary histories, the First World War and the Armenian Genocide

In April 2015 the centenary of the Armenian Genocide was commemorated. Just like the First World War centenary, this anniversary has provoked a flurry of academic and public interest in what remains a highly contested history. This article assesses the state of the current historiography on the fate of the Ottoman Armenians. It focuses on the possibilities for moving beyond the national narratives which continue to dominate the field, in particular through connecting the case of the Armenian Genocide to what has been termed a ‘transnational turn’ in the writing of the history of the First World War

Discrimination of pancreatic cancer and pancreatitis by LC-MS metabolomics

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is the fifth most common cause of cancer-related death in Europe with a 5-year survival rate of <5%. Chronic pancreatitis (CP) is a risk factor for PDAC development, but in the majority of cases malignancy is discovered too late for curative treatment. There is at present no reliable diagnostic marker for PDAC available. Objectives: The aim of the study was to identify single blood-based metabolites or a panel of metabolites discriminating PDAC and CP using liquid chromatography-mass spectrometry (LC-MS). Methods: A discovery cohort comprising PDAC (n = 44) and CP (n = 23) samples was analyzed by LC-MS followed by univariate (Student’s t test) and multivariate (orthogonal partial least squares-discriminant analysis (OPLS-DA)) statistics. Discriminative metabolite features were subject to raw data examination and identification to ensure high feature quality. Their discriminatory power was then confirmed in an independent validation cohort including PDAC (n = 20) and CP (n = 31) samples. Results: Glycocholic acid, N-palmitoyl glutamic acid and hexanoylcarnitine were identified as single markers discriminating PDAC and CP by univariate analysis. OPLS-DA resulted in a panel of five metabolites including the aforementioned three metabolites as well as phenylacetylglutamine (PAGN) and chenodeoxyglycocholate. Conclusion: Using LC-MS-based metabolomics we identified three single metabolites and a five-metabolite panel discriminating PDAC and CP in two independent cohorts. Although further study is needed in larger cohorts, the metabolites identified are potentially of use in PDAC diagnostics

Spatial and developmental heterogeneity of calcium signaling in olfactory ensheathing cells

Olfactory ensheathing cells (OECs) are specialized glial cells in the mammalian olfactory system supporting growth of axons from the olfactory epithelium into the olfactory bulb. OECs in the olfactory bulb can be subdivided into OECs of the outer nerve layer and the inner nerve layer according to the expression of marker proteins and their location in the nerve layer. In the present study, we have used confocal calcium imaging of OECs in acute mouse brain slices and olfactory bulbs in toto to investigate physiological differences between OEC subpopulations. OECs in the outer nerve layer, but not the inner nerve layer, responded to glutamate, ATP, serotonin, dopamine, carbachol, and phenylephrine with increases in the cytosolic calcium concentration. The calcium responses consisted of a transient and a tonic component, the latter being mediated by store-operated calcium entry. Calcium measurements in OECs during the first three postnatal weeks revealed a downregulation of mGluR(1) and P2Y(1) receptor-mediated calcium signaling within the first 2 weeks, suggesting that the expression of these receptors is developmentally controlled. In addition, electrical stimulation of sensory axons evoked calcium signaling via mGluR(1) and P2Y(1) only in outer nerve layer OECs. Downregulation of the receptor-mediated calcium responses in postnatal animals is reflected by a decrease in amplitude of stimulation-evoked calcium transients in OECs from postnatal days 3 to 21. In summary, the results presented reveal striking differences in receptor responses during development and in axon-OEC communication between the two subpopulations of OECs in the olfactory bulb