221 research outputs found
Capacitive Deionization for Selective Extraction of Lithium from Aqueous Solutions
The paper deals with extraction of lithium by means of two capacitive deionization systems: one composed of lithium selective electrode and second with electrode wrapped with Li-selective membrane. In the case of the first system, hybrid electrodes where obtained by mixing λ-MnO2sorbent with activated carbon .The best Li-capacity was determined for electrode with 20 wt.-% of manganese oxide. For larger amounts of λ-MnO2 the electrode capacity decreased significantly. The second system was composed of carbon electrodes wrapped with ion-exchange membranes. The lithium selective membranes were synthesized by plasma induced interpolymerization of (meth)acrylic monomersinpores of Celgard 2400 support. Two functional monomers, poly(di(ethylene glycol)methyl ether methacrylate) and poly(glycidylmethacylate modified with hydroxymethyl-12-crown-4) were copolymerized with acrylic acid. It was found that the extraction of lithium chloride was the best for membrane caring copolymers of acrylic acid and glycidyl methacrylate modified with crown ether, andit was better than for membranes with sole poly(acrylic acid)
Electro-driven materials and processes for lithium recovery—A review
The mass production of lithium-ion batteries and lithium-rich e-products that are required for electric vehicles, energy storage devices, and cloud-connected electronics is driving an unprecedented demand for lithium resources. Current lithium production technologies, in which extraction and purification are typically achieved by hydrometallurgical routes, possess strong environmental impact but are also energy-intensive and require extensive operational capabilities. The emergence of selective membrane materials and associated electro-processes offers an avenue to reduce these energy and cost penalties and create more sustainable lithium production approaches. In this review, lithium recovery technologies are discussed considering the origin of the lithium, which can be primary sources such as minerals and brines or e-waste sources generated from recycling of batteries and other e-products. The relevance of electro-membrane processes for selective lithium recovery is discussed as well as the potential and shortfalls of current electro-membrane methods
Revisiting wetting, freezing, and evaporation mechanisms of water on copper
Wetting of metal surfaces plays an important role in fuel cells, corrosion science, and heat-transfer devices. It has been recently stipulated that Cu surface is hydrophobic. In order to address this issue we use high purity (1 1 1) Cu prepared without oxygen, and resistant to oxidation. Using the modern Fringe Projection Phase-Shifting method of surface roughness determination, together with a new cell allowing the vacuum and thermal desorption of samples, we define the relation between the copper surface roughness and water contact angle (WCA). Next by a simple extrapolation, we determine the WCA for the perfectly smooth copper surface (WCA = 34°). Additionally, the kinetics of airborne hydrocarbons adsorption on copper was measured. It is shown for the first time that the presence of surface hydrocarbons strongly affects not only WCA, but also water droplet evaporation and the temperature of water droplet freezing. The different behavior and features of the surfaces were observed once the atmosphere of the experiment was changed from argon to air. The evaporation results are well described by the theoretical framework proposed by Semenov, and the freezing process by the dynamic growth angle model
Bloggers Behavior and Emergent Communities in Blog Space
Interactions between users in cyberspace may lead to phenomena different from
those observed in common social networks. Here we analyse large data sets about
users and Blogs which they write and comment, mapped onto a bipartite graph. In
such enlarged Blog space we trace user activity over time, which results in
robust temporal patterns of user--Blog behavior and the emergence of
communities. With the spectral methods applied to the projection on weighted
user network we detect clusters of users related to their common interests and
habits. Our results suggest that different mechanisms may play the role in the
case of very popular Blogs. Our analysis makes a suitable basis for theoretical
modeling of the evolution of cyber communities and for practical study of the
data, in particular for an efficient search of interesting Blog clusters and
further retrieval of their contents by text analysis
Prospective association of occupational and leisure-time physical activity with orthostatic blood pressure changes in older adults
\ua9 2023, The Author(s).Orthostatic hypotension (OH) is common in older people. We examined the influence of self-reported occupational-related physical activity (PA) and leisure-time physical exercise (PE) on orthostatic response in a sample of older people over a 2 year period. Supine and orthostatic systolic blood pressure (sBP), diastolic blood pressure (dBP), and mean blood pressure (mBP) were assessed in response to Active Stand (AS) test in 205 older subjects (> 60 years old) at baseline and 2-year follow-up. OH was found in 24 subjects (11.71%) at baseline and 20 subjects (9.76%) after 2 years, with a significant degree of variability in the occurrence of OH after 2 years. Twenty-two subjects who had OH at baseline were free of it after 2 years, two subjects had persistent OH at baseline and after 2 years. After 2 years, adults with occupational PA showed no significant decrease of blood pressure in response to AS test, while lack of undertaking an occupation-related PA was significantly related with a greater decrease in sBP and mBP in response to AS testing in the 1st min. Occupation-related PA and leisure-time-related PE were related to an increase in the response of BP on AS in change between baseline and after 2 years. High between-subjects variance in OH over 2 years was noted. Occupations that involved continuous physical activity and leisure-time physical exercise in middle age were both protective for BP decline on orthostatic stress test within 2 years
Persistent viral shedding of SARS‐CoV‐2 in faeces – a rapid review
Aim
In addition to respiratory symptoms, COVID‐19 can present with gastrointestinal complaints suggesting possible faeco‐oral transmission. The primary aim of this review was to establish the incidence and timing of positive faecal samples for SARS‐CoV‐2 in patients with COVID‐19.
Methods
A systematic literature review identified studies describing COVID‐19 patients tested for faecal virus. Search terms for MEDLINE included ‘clinical’, ‘faeces’, ‘gastrointestinal secretions’, ‘stool’, ‘COVID‐19’, ‘SARS‐CoV‐2’ and ‘2019‐nCoV’. Additional searches were done in the American Journal of Gastroenterology , Gastroenterology , Gut , Lancet Gastroenterology and Hepatology , the World Health Organization Database, the Centre for Evidence‐Based Medicine, New England Journal of Medicine , social media and the National Institute for Health and Care Excellence, bioRxiv and medRxiv preprints. Data were extracted concerning the type of test, number and timing of positive samples, incidence of positive faecal tests after negative nasopharyngeal swabs and evidence of viable faecal virus or faeco‐oral transmission of the virus.
Results
Twenty‐six relevant articles were identified. Combining study results demonstrated that 53.9% of those tested for faecal RNA were positive. The duration of faecal viral shedding ranged from 1 to 33 days after a negative nasopharyngeal swab with one result remaining positive 47 days after onset of symptoms. There is insufficient evidence to suggest that COVID‐19 is transmitted via faecally shed virus.
Conclusion
There is a high rate of positive polymerase chain reaction tests with persistence of SARS‐CoV‐2 in faecal samples of patients with COVID‐19. Further research is needed to confirm if this virus is viable and the degree of transmission through the faeco‐oral route. This may have important implications on isolation, recommended precautions and protective equipment for interventional procedures involving the gastrointestinal tract
Collective emotions online and their influence on community life
E-communities, social groups interacting online, have recently become an
object of interdisciplinary research. As with face-to-face meetings, Internet
exchanges may not only include factual information but also emotional
information - how participants feel about the subject discussed or other group
members. Emotions are known to be important in affecting interaction partners
in offline communication in many ways. Could emotions in Internet exchanges
affect others and systematically influence quantitative and qualitative aspects
of the trajectory of e-communities? The development of automatic sentiment
analysis has made large scale emotion detection and analysis possible using
text messages collected from the web. It is not clear if emotions in
e-communities primarily derive from individual group members' personalities or
if they result from intra-group interactions, and whether they influence group
activities. We show the collective character of affective phenomena on a large
scale as observed in 4 million posts downloaded from Blogs, Digg and BBC
forums. To test whether the emotions of a community member may influence the
emotions of others, posts were grouped into clusters of messages with similar
emotional valences. The frequency of long clusters was much higher than it
would be if emotions occurred at random. Distributions for cluster lengths can
be explained by preferential processes because conditional probabilities for
consecutive messages grow as a power law with cluster length. For BBC forum
threads, average discussion lengths were higher for larger values of absolute
average emotional valence in the first ten comments and the average amount of
emotion in messages fell during discussions. Our results prove that collective
emotional states can be created and modulated via Internet communication and
that emotional expressiveness is the fuel that sustains some e-communities.Comment: 23 pages including Supporting Information, accepted to PLoS ON
Invited Article: First Flight in Space of a Wide-Field-of-View Soft X-Ray Imager Using Lobster-Eye Optics: Instrument Description and Initial Flight Results
We describe the development, launch into space, and initial results from a prototype wide eld-of-view (FOV) soft X-ray imager that employs Lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The Sheath Transport Observer for the Redistribution of Mass (STORM) is the rst instrument using this type of optics launched into space and provides proof-of-concept for future ight instruments capable of imaging structures such as the terrestrial cusp, the entire dayside magnetosheath from outside the magnetosphere, comets, the moon, and the solar wind interaction with planetary bodies like Venus and Mars
Relationship between Cardiopulmonary, Mitochondrial and Autonomic Nervous System Function Improvement after an Individualised Activity Programme upon Chronic Fatigue Syndrome Patients
Background: The therapeutic effects of exercise from structured activity programmes have recently been questioned; as a result, this study examines the impact of an Individualised Activity Program (IAP) on the relationship with cardiovascular, mitochondrial and fatigue parameters. Methods: Chronic fatigue syndrome (CFS) patients were assessed using Chalder Fatigue Questionnaire (CFQ), Fatigue Severity Score (FSS) and the Fatigue Impact Scale (FIS). VO(2)peak, VO(2)submax and heart rate (HR) were assessed using cardiopulmonary exercise testing. Mfn1 and Mfn2 levels in plasma were assessed. A Task Force Monitor was used to assess ANS functioning in supine rest and in response to the Head-Up Tilt Test (HUTT). Results: Thirty-four patients completed 16 weeks of the IAP. The CFQ, FSS and FIS scores decreased significantly along with a significant increase in Mfn1 and Mfn2 levels (p = 0.002 and p = 0.00005, respectively). The relationships between VO2 peak and Mfn1 increase in response to IAP (p = 0.03) and between VO2 at anaerobic threshold and ANS response to the HUTT (p = 0.03) were noted. Conclusions: It is concluded that IAP reduces fatigue and improves functional performance along with changes in autonomic and mitochondrial function. However, caution must be applied as exercise was not well tolerated by 51% of patients
Prediction of discontinuation of structured exercise programme in chronic fatigue syndrome patients.
Purpose: The purpose of this study was to assess differences in the physiological profiles of completers vs. non-completers following a structured exercise programme (SEP) and the ability to predict non-completers, which is currently unknown in this group. Methods: Sixty-nine patients met the Fukuda criteria. Patients completed baseline measures assessing fatigue, autonomic nervous system (ANS), cognitive, and cardiovascular function. Thirty-four patients completed a home-based SEP consisting of 10–40 min per day at between 30 and 80% actual HR max. Exercise intensity and time was increased gradually across the 16 weeks and baseline measures were repeated following the SEP. Results: Thirty-five patients discontinued, while 34 completed SEP. For every increase in sympathetic drive for blood pressure control as measured by the taskforce, completion of SEP decreased by a multiple of 0.1. For a 1 millisecond increase in reaction time for the simple reaction time (SRT), the probability for completion of SEP also decreases by a multiple of 0.01. For a one beat HRmax increase, there is a 4% increase in the odds of completing SEP. Conclusion: The more sympathetic drive in the control of blood vessels, the longer the reaction time on simple visual stimuli and the lower the HRmax during physical exercise, then the lower the chance of SEP completion in ME/CFS
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