716 research outputs found
Aliphatic + ethanol separation via liquid-liquid extraction using low transition temperature mixtures as extracting agents
In this work, two different low transition temperature mixtures (LTTMs), e.g., (i) glycolic acid–choline chloride molar ratio = (1:1) (GC(1:1)) and (ii) lactic acid–choline chloride molar ratio = (2:1) (LC(2:1)), were evaluated as potential extracting agents for the separation of the azeotropic mixtures {hexane + ethanol} and {heptane + ethanol}. Firstly, the liquid–liquid equilibrium (LLE) data of the ternary systems {hexane + ethanol + LTTM} and {heptane + ethanol + LTTM} were experimentally determined at T/K = 298.15 and T/K = 308.15. Secondly, the solute distribution coefficient and selectivity were calculated and analyzed. The influence of the temperature on the phase behavior and the performance of the LTTMs related to the chain length of the hydrocarbon were considered. A literature comparison with other extracting agents used for the separation of these mixtures was performed in order to evaluate the suitability of the studied LTTMs. Moreover, the recyclability of the extraction agent, which is of great importance in liquid–liquid extraction, was demonstrated. Finally, the experimental data were successfully fitted using the NRTL model. It was found that both LTTMs show a competitive performance compared to existing extracting agents. It was also established that both in the {hexane + ethanol} and {heptane + ethanol} separation, the LC(2:1) showed higher distribution coefficient than the GC(1:1), while the opposite trend was found for the selectivity values
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
TRY plant trait database - enhanced coverage and open access
Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
Clinical and Biomarker Changes in Dominantly Inherited Alzheimer's Disease
BACKGROUND: The order and magnitude of pathologic processes in Alzheimer's disease are not well understood, partly because the disease develops over many years. Autosomal dominant Alzheimer's disease has a predictable age at onset and provides an opportunity to determine the sequence and magnitude of pathologic changes that culminate in symptomatic disease. METHODS: In this prospective, longitudinal study, we analyzed data from 128 participants who underwent baseline clinical and cognitive assessments, brain imaging, and cerebrospinal fluid (CSF) and blood tests. We used the participant's age at baseline assessment and the parent's age at the onset of symptoms of Alzheimer's disease to calculate the estimated years from expected symptom onset (age of the participant minus parent's age at symptom onset). We conducted cross-sectional analyses of baseline data in relation to estimated years from expected symptom onset in order to determine the relative order and magnitude of pathophysiological changes. RESULTS: Concentrations of amyloid-beta (Aβ)(42) in the CSF appeared to decline 25 years before expected symptom onset. Aβ deposition, as measured by positron-emission tomography with the use of Pittsburgh compound B, was detected 15 years before expected symptom onset. Increased concentrations of tau protein in the CSF and an increase in brain atrophy were detected 15 years before expected symptom onset. Cerebral hypometabolism and impaired episodic memory were observed 10 years before expected symptom onset. Global cognitive impairment, as measured by the Mini-Mental State Examination and the Clinical Dementia Rating scale, was detected 5 years before expected symptom onset, and patients met diagnostic criteria for dementia at an average of 3 years after expected symptom onset. CONCLUSIONS: We found that autosomal dominant Alzheimer's disease was associated with a series of pathophysiological changes over decades in CSF biochemical markers of Alzheimer's disease, brain amyloid deposition, and brain metabolism as well as progressive cognitive impairment. Our results require confirmation with the use of longitudinal data and may not apply to patients with sporadic Alzheimer's disease. (Funded by the National Institute on Aging and others; DIAN ClinicalTrials.gov number, NCT00869817.)
Performance and Operation of the CMS Electromagnetic Calorimeter
The operation and general performance of the CMS electromagnetic calorimeter
using cosmic-ray muons are described. These muons were recorded after the
closure of the CMS detector in late 2008. The calorimeter is made of lead
tungstate crystals and the overall status of the 75848 channels corresponding
to the barrel and endcap detectors is reported. The stability of crucial
operational parameters, such as high voltage, temperature and electronic noise,
is summarised and the performance of the light monitoring system is presented
Effects of impurities on the ice microstructure of Monte Perdido Glacier, Central Pyrenees, NE Spain
Monte Perdido Glacier, located in the central Pyrenees, is one of the southernmost glaciers in Europe. Due to climate change, this glacier is suffering an accelerated mass loss, especially in the last decades. If the current trends persist, this glacier is expected to disappear in the next 50 years. As part of the efforts of the scientific community to increase the knowledge about this glacier, this research presents the first microstructural characterization of the Monte Perdido Glacier, focused on a high-impurity concentration segment that belongs to an ice core drilled in 2017. The results reveal the ice has a layering defined by air bubbles and non-soluble impurities. The bubble-defined layering exhibits features of both a primary (sedimentary) and a secondary (strain-induced) origin. We found a clear inverse correspondence between the particle concentration and the grains' size and roundness index. A preliminary micro-Raman characterization of the particles shows the occurrence of atacamite, anatase (likely related to ancient mining activities in the vicinity of the glacier) and quartz. The latter could be an indicator of mineral dust, probably suggesting the arrival of dust-laden air masses from the north of the African continent.This research was supported by the Spanish Government through the María de Maeztu excellence accreditation 2018–2022 (MDM-2017-0714) and by the Spanish Agencia Estatal de Investigación (AEI Spain) through the projects PaleoICE EXPLORA (CGL2015-72167-EXP) and iMechPro (RTI2018-100696-B-I00). NGS acknowledges a PhD grant from the Basque Government (PRE-2018-1-0116). We thank the directorate of the Parque Nacional de Ordesa y Monte Perdido (Spain) for permission to investigate the Monte Perdido glacier. We also thank Ibai Rico ( https://basquemountainguides.com/ , UPV/EHU), Maria Leunda (UPV/EHU), and Juan Ignacio López-Moreno (IPE-CSIC) for their help during the sampling of the MP1 ice core, and Pedro Sanchez Navarrete (IPE-CSIC) for transporting the ice samples. Finally, we would like to extend our appreciation to the anonymous reviewers, the Scientific Editor, Christine Hvidberg, and the Chief Editor, Hester Jiskoot, for their valuable comments on this manuscript
Towards energy transition in Tunisia: Sustainability assessment of a hybrid concentrated solar power and biomass plant
Electricity demand in the Middle East and North Africa (MENA) region increases at a rate of 6???8% per year. It is expected to double by 2020 and triple by 2030. Renewable electricity ensures climate protection and energy security. This work presents a sustainability assessment of CSP hybridization with biomass technology to be installed in Tunisia. Environmental impacts have been assessed by Life Cycle Analysis (LCA). For socioeconomic impacts, a Multiregional Input-Output (MRIO) analysis was used to estimate the production of goods and services, value added and employment creation. Regarding the results, the system reports 22 gCO2eq per kWh. The most important component in terms of emissions is the gasifier system, due to biomass transport. Socioeconomic results show important impacts for employment creation in Tunisia, coming essentially from the O&M phase. The multiplier effect of the direct investment for production of goods and services amounts to 2.4 (3.5 accounting induced effects). Domestic value added in investment is low, only 28.9% of the overall value added created. Thus, increasing the national content of the investment stage would bring additional local benefits. Using extended MRIO, CO2 emissions have also been calculated and differences in the CO2 emission with both methodologies are discussed
Complementary intestinal mucosa and microbiota responses to caloric restriction
The intestine is key for nutrient absorption and for interactions between the microbiota and its host. Therefore, the intestinal response to caloric restriction (CR) is thought to be more complex than that of any other organ. Submitting mice to 25% CR during 14 days induced a polarization of duodenum mucosa cell gene expression characterised by upregulation, and downregulation of the metabolic and immune/inflammatory pathways, respectively. The HNF, PPAR, STAT, and IRF families of transcription factors, particularly the Pparα and Isgf3 genes, were identified as potentially critical players in these processes. The impact of CR on metabolic genes in intestinal mucosa was mimicked by inhibition of the mTOR pathway. Furthermore, multiple duodenum and faecal metabolites were altered in CR mice. These changes were dependent on microbiota and their magnitude corresponded to microbial density. Further experiments using mice with depleted gut bacteria and CR-specific microbiota transfer showed that the gene expression polarization observed in the mucosa of CR mice is independent of the microbiota and its metabolites. The holistic interdisciplinary approach that we applied allowed us to characterize various regulatory aspects of the host and microbiota response to CR
Application of a new protocol for providing obstetric care in an outpatient service during the COVID-19 pandemic in a public hospital in Madrid, Spain.
Objective: To evaluate the clinical implementation of a preventive COVID-19 protocol regarding re-organization of appointments and documented infections among health workers in an obstetric outpatient service.
Methods: Descriptive analysis of the antenatal care at our obstetric outpatient service and infection rates among health care providers from March 19th to May 22nd, 2020. Appointments were divided into telephone calls or face-to-face examinations. A pre-consultation triage was implemented to identify suspected SARS-CoV2 infected women to reschedule them 14 days later or, if the consultation was non-delayable, to use complete Personal Protective Equipment (PPE). Firstly, the number of face-to-face appointments, telephone appointments, and COVID-19 diagnoses in pregnant women were analyzed. Secondly, the number of obstetricians and nurses diagnosed with SARS-CoV2 infection and their serologic status during universal screening in May 2020 were recorded.
Results: One thousand eight hundred forty-two obstetric appointments were scheduled during this period, including 432 (23.5%) telephone appointments (96.53% according to clinical protocol, 1.62% symptomatic patients advised to stay at home, and 1.85% COVID-19 confirmed cases), and 1,410 (76.5%) face-to-face appointments (9.7% did not attend due to fear of getting the infection, 3.1% were lost-to-follow-up, 0.5% were rescheduled due to COVID-19 symptoms and 86.7% who did attend). Of the 1,223 women attending their hospital appointment, 3.6% screened positive at the triage (72.7% rescheduled and 27.3% seen with PPE). 43 rRT-PCR-SARS-CoV2 tests were performed, and two tested positive. No COVID-19 symptoms were reported among health workers at the outpatient obstetric service, and only one nurse presented immunoglobulin (Ig)G anti-SARS-CoV2.
Conclusion: A prompt implementation of a preventive protocol in a hospital obstetric outpatient service, including triage, hygienic and preventive measurements, and rescheduling pregnancy appointments, reduces the percentage of health workers affected by SARS-CoV2.post-print369 K
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