54 research outputs found

    Composite Membranes Derived from Cellulose and Lignin Sulfonate for Selective Separations and Antifouling Aspects

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    Cellulose-based membrane materials allow for separations in both aqueous solutions and organic solvents. The addition of nanocomposites into cellulose structure is facilitated through steric interaction and strong hydrogen bonding with the hydroxy groups present within cellulose. An ionic liquid, 1-ethyl-3-methylimidazolium acetate, was used as a solvent for microcrystalline cellulose to incorporate graphene oxide quantum dots into cellulose membranes. In this work, other composite materials such as, iron oxide nanoparticles, polyacrylic acid, and lignin sulfonate have all been uniformly incorporated into cellulose membranes utilizing ionic liquid cosolvents. Integration of iron into cellulose membranes resulted in high selectivity (\u3e 99%) of neutral red and methylene blue model dyes separation over salts with a high permeability of 17 LMH/bar. With non-aqueous (alcohol) solvent, iron–cellulose composite membranes become less selective and more permeable, suggesting the interaction of iron ions cellulose OH groups plays a major role in pore structure. Polyacrylic acid was integrated into cellulose membranes to add pH responsive behavior and capacity for metal ion capture. Calcium capture of 55 mg Ca2+/g membrane was observed for PAA-cellulose membranes. Lignin sulfonate was also incorporated into cellulose membranes to add strong negative charge and a steric barrier to enhance antifouling behavior. Lignin sulfonate was also functionalized on the commercial DOW NF270 nanofiltration membranes via esterification of hydroxy groups with carboxyl group present on the membrane surface. Antifouling behavior was observed for both lignin-cellulose composite and commercial membranes functionalized with lignin. Up to 90% recovery of water flux after repeated cycles of fouling was observed for both types of lignin functionalized membranes while flux recovery of up to 60% was observed for unmodified membranes

    Risk of intracranial haemorrhage and ischaemic stroke after convexity subarachnoid haemorrhage in cerebral amyloid angiopathy: international individual patient data pooled analysis

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    OBJECTIVE: To investigate the frequency, time-course and predictors of intracerebral haemorrhage (ICH), recurrent convexity subarachnoid haemorrhage (cSAH), and ischemic stroke after cSAH associated with cerebral amyloid angiopathy (CAA). METHODS: We performed a systematic review and international individual patient-data pooled analysis in patients with cSAH associated with probable or possible CAA diagnosed on baseline MRI using the modified Boston criteria. We used Cox proportional hazards models with a frailty term to account for between-cohort differences. RESULTS: We included 190 patients (mean age 74.5 years; 45.3% female) from 13 centers with 385 patient-years of follow-up (median 1.4 years). The risks of each outcome (per patient-year) were: ICH 13.2% (95% CI 9.9-17.4); recurrent cSAH 11.1% (95% CI 7.9-15.2); combined ICH, cSAH, or both 21.4% (95% CI 16.7-26.9), ischemic stroke 5.1% (95% CI 3.1-8) and death 8.3% (95% CI 5.6-11.8). In multivariable models, there is evidence that patients with probable CAA (compared to possible CAA) had a higher risk of ICH (HR 8.45, 95% CI 1.13-75.5, p = 0.02) and cSAH (HR 3.66, 95% CI 0.84-15.9, p = 0.08) but not ischemic stroke (HR 0.56, 95% CI 0.17-1.82, p = 0.33) or mortality (HR 0.54, 95% CI 0.16-1.78, p = 0.31). CONCLUSIONS: Patients with cSAH associated with probable or possible CAA have high risk of future ICH and recurrent cSAH. Convexity SAH associated with probable (vs possible) CAA is associated with increased risk of ICH, and cSAH but not ischemic stroke. Our data provide precise risk estimates for key vascular events after cSAH associated with CAA which can inform management decisions

    Microfluidic Paper-Based Analytical Devices (ÎŒPADs) and Micro Total Analysis Systems (ÎŒTAS): Development, Applications and Future Trends

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    Contemplating stem cell therapy for epilepsy-induced neuropsychiatric symptoms

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    Gautam Rao, Sherwin Mashkouri, David Aum, Paul Marcet, Cesar V Borlongan Department of Neurosurgery and Brain Repair, Center of Excellence for Aging and Brain Repair, University of South Florida Morsani College of Medicine, Tampa, FL, USA Abstract: Epilepsy is a debilitating disease that impacts millions of people worldwide. While unprovoked seizures characterize its cardinal symptom, an important aspect of epilepsy that remains to be addressed is the neuropsychiatric component. It has been documented for millennia in paintings and literature that those with epilepsy can suffer from bouts of aggression, depression, and other psychiatric ailments. Current treatments for epilepsy include the use of antiepileptic drugs and surgical resection. Antiepileptic drugs reduce the overall firing of the brain to mitigate the rate of seizure occurrence. Surgery aims to remove a portion of the brain that is suspected to be the source of aberrant firing that leads to seizures. Both options treat the seizure-generating neurological aspect of epilepsy, but fail to directly address the neuropsychiatric components. A promising new treatment for epilepsy is the use of stem cells to treat both the biological and psychiatric components. Stem cell therapy has been shown efficacious in treating experimental models of neurological disorders, including Parkinson’s disease, and neuropsychiatric diseases, such as depression. Additional research is necessary to see if stem cells can treat both neurological and neuropsychiatric aspects of epilepsy. Currently, there is no animal model that recapitulates all the clinical hallmarks of epilepsy. This could be due to difficulty in characterizing the neuropsychiatric component of the disease. In advancing stem cell therapy for treating epilepsy, experimental testing of the safety and efficacy of allogeneic and autologous transplantation will require the optimization of cell dosage, delivery, and timing of transplantation in a clinically relevant model of epilepsy with both neurological and neuropsychiatric symptoms of the disease as the primary outcome measures. Keywords: epilepsy, neuropsychiatric, stem cells, autologous&nbsp

    Hot-carrier degradation of CMOS inverters and ring oscillators at 77K

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    The impact of hot-carrier (HC) stress on CMOS inverters at 77K was examined as a function of temperature. It was found that the degradation in inverter propagation delay was about one order less than that of the device transconductance degradation. Activation energy (EA) of propagation delay exhibited two distinct values from 295K to 77K, with a transition at around 175K for virgin and stressed inverters. The improvement of propagation delay and voltage transfer characteristic (VTC) at 77K compared to 295K was larger for virgin than HC stressed inverters

    SemEval-2023 Task 11: Learning With Disagreements (LeWiDi)

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    The paper contains examples which are offensive in nature. nlp datasets annotated with human judgments are rife with disagreements between the judges. This is especially true for tasks depending on subjective judgments such as sentiment analysis or offensive language detection. Particularly in these latter cases, the nlp community has come to realize that the approach of ‘reconciling’ these different subjective interpretations is inappropriate. Many nlp researchers have therefore concluded that rather than eliminating disagreements from annotated corpora, we should preserve them–indeed, some argue that corpora should aim to preserve all annotator judgments. But this approach to corpus creation for nlp has not yet been widely accepted. The objective of the LeWiDi series of shared tasks is to promote this approach to developing nlp models by providing a unified framework for training and evaluating with such datasets. We report on the second LeWiDi shared task, which differs from the first edition in three crucial respects: (i) it focuses entirely on nlp, instead of both nlp and computer vision tasks in its first edition; (ii) it focuses on subjective tasks, instead of covering different types of disagreements–as training with aggregated labels for subjective nlp tasks is a particularly obvious misrepresentation of the data; and (iii) for the evaluation, we concentrate on soft approaches to evaluation. This second edition of LeWiDi attracted a wide array of participants resulting in 13 shared task submission papers

    A Study on continuous and intermittent THAI processes in Brazil's Northeastern Region

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    Toe-to-Heel Air Injection - THAI is an enhanced oil recovery technique that employs in situ combustion combined with technologies for horizontal well drilling, which is unprecedented in Brazilian oilfields. Motivated by this context, this research is intended to studying the application of the THAI process in a semisynthetic reservoir, with characteristics similar to those found in Brazil's Northeastern region. At the end, it was demonstrated that the intermittent air injection increased the oil recovery, when compared to the continuous injection, what reinforce the need for further research turned to ongoing and future projects in mature oilfields.Fed Univ Para, Engn Coll, BR-68721000 Salinopolis, Para, BrazilUniv Fed Alagoas, Dept Petr Engn, Maceio, Alagoas, BrazilUniv Fed Rio Grande do Norte, Postgrad Program Petr Engn, Natal, RN, BrazilUniv Fed Paraiba, Dept Comp Sci, Joao Pessoa, Paraiba, BrazilUniv Fed Sao Paulo, Dept Marine Sci, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Marine Sci, Sao Paulo, BrazilWeb of Scienc
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