1,241 research outputs found

    Study of Ceramic Membrane from Naturally Occurring-Kaolin Clays for Microfiltration Applications

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    The focus of this work is to assess the quality of porous membranes prepared from naturally occurring kaolin clays and to evaluate the performance of tubular ceramic membranes treating integrated raw effluents from seafood industry. This material has been chosen due to its natural abundance, its non-toxicity, low cost and its valuable properties. The preparation and characterization of porous tubular ceramic membranes, using kaolin powder with and without corn starch as poreforming agent, were reported. SEM photographs indicated that the membrane surface was homogeneous. The effects of material compositions, additives and the relatively lower sintering temperature, ranging from 1100° to 1250°C, on porosity, average pore size, pore-size distribution and mechanical strength of membranes have been investigated. A correlation between microstructure and mechanical properties of membranes has been discussed. The performance of the novel ceramic membranes thus obtained was determined by evaluating both the water permeability and rejection. The obtained membrane was used to treat cuttlefish effluents generated from the conditioning seawater product industry which consumes a great amount of water. Cross-flow microfiltration was performed then, in order to reduce the turbidity and chemical oxygen demand (COD).

    Fabrication, Characterization and Permeation Studies of Ionically Cross-linked Chitosan/Kaolin Composite Membranes

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    This paper presents the successful preparation of porous membranes based on chitosan with enhanced mechanical, thermal and chemical properties applicable in water treatment field. Herein, chitosan/kaolin composite membranes with a cross-linking agent and a porogen were prepared using the solvent casting method. The characterization of the as-fabricated membranes indicated that the combined effect of kaolin as reinforcing agent, polyethylene glycol as pore former and citric acid as cross-linker in a chitosan matrix showed a significant influence on the membrane properties. The results indicated that the incorporation of a hydrophilic porogenic reagent into the collodion in addition to providing a porous morphology makes it possible to obtain a more hydrophilic membrane, and thus induces an increase in the pure water permeability. The cross-linked membranes exhibited an improved water resistance, better thermal and mechanical properties as compared to neat chitosan films. The cross-linked membranes had a mean pore size of 50 nm falling in the range of ultrafiltration. Their functional properties were determined in terms of pure water filtration and molecular weight cut-off tests

    High index contrast photonic platforms for on-chip Raman spectroscopy

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    Nanophotonic waveguide enhanced Raman spectroscopy (NWERS) is a sensing technique that uses a highly confined waveguide mode to excite and collect the Raman scattered signal from molecules in close vicinity of the waveguide. The most important parameters defining the figure of merit of an NWERS sensor include its ability to collect the Raman signal from an analyte, i.e. "the Raman conversion efficiency" and the amount of "Raman background" generated from the guiding material. Here, we compare different photonic integrated circuit (PIC) platforms capable of on-chip Raman sensing in terms of the aforementioned parameters. Among the four photonic platforms under study, tantalum oxide and silicon nitride waveguides exhibit high signal collection efficiency and low Raman background. In contrast, the performance of titania and alumina waveguides suffers from a strong Raman background and a weak signal collection efficiency, respectively

    Formulation and Implementation of Frequency-Dependent Linear Response Properties with Relativistic Coupled Cluster Theory for GPU-accelerated Computer Architectures

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    We present the development and implementation of the relativistic coupled cluster linear response theory (CC-LR) which allows the determination of molecular properties arising from time-dependent or time-independent electric, magnetic, or mixed electric-magnetic perturbations (within a common gauge origin), and take into account the finite lifetime of excited states via damped response theory. We showcase our implementation, which is capable to offload intensive tensor contractions onto graphical processing units (GPUs), in the calculation of: \textit{(a)} frequency-(in)dependent dipole-dipole polarizabilities of IIB atoms and selected diatomic molecules, with a emphasis on the calculation of valence absorption cross-sections for the I2_2 molecule;\textit{(b)} indirect spin-spin coupling constants for benchmark systems such as the hydrogen halides (HX, X = F-I) as well the H2_2Se-H2_2O dimer as a prototypical system containing hydrogen bonds; and \textit{(c)} optical rotations at the sodium D line for hydrogen peroxide analogues (H2_{2}Y2_{2}, Y=O, S, Se, Te). Thanks to this implementation, we are able show the similarities in performance--but often the significant discrepancies--between CC-LR and approximate methods such as density functional theory (DFT). Comparing standard CC response theory with the equation of motion formalism, we find that, for valence properties such as polarizabilities, the two frameworks yield very similar results across the periodic table as found elsewhere in the literature; for properties that probe the core region such as spin-spin couplings, we show a progressive differentiation between the two as relativistic effects become more important. Our results also suggest that as one goes down the periodic table it may become increasingly difficult to measure pure optical rotation at the sodium D line, due to the appearance of absorbing states

    Family bereavement care interventions during the COVID-19 pandemic: a scoping review protocol

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    The COVID-19 pandemic has caused significant disruptions to daily social routines and to the lived experience of bereaved families. This article outlines the protocol for a scoping review of published studies to evaluate psychosocial and psychotherapeutic interventions intended to help family carers adjust to grief, loss and bereavement due to COVID-19. This review addresses one broad research question: ‘What do we know about bereavement support interventions for family carers of COVID-19 victims?info:eu-repo/semantics/publishedVersio

    Systematic Review and Critical Analysis of Cost Studies Associated with Parkinson's Disease

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    Parkinson's disease (PD) is the second most prevalent neurodegenerative disease worldwide, affecting more than four million people. Typically, it affects individuals above 45, when they are still productive, compromising both aging and quality of life. Therefore, the cost of the disease must be identified, so that the use of resources can be rational and efficient. Additionally, in Brazil, there is a lack of research on the costs of neurodegenerative diseases, such as PD, a gap addressed in this study. This systematic review critically addresses the various methodologies used in original research around the world in the last decade on the subject, showing that costs are hardly comparable. Nonetheless, the economic and social impacts are implicit, and important information for public health agents is provided.Hosp Israelita Albert Einstein, Programa Posgrad, Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP, Movement Disorders Dept Neurol, Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP, Sao Paulo, SP, BrazilHosp Israelita Albert Einstein, Neurol Program, Sao Paulo, SP, BrazilMovement Disorders Department in Neurology, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, BrazilUniversidade Federal de São Paulo (UNIFESP), São Paulo, SP, BrazilWeb of Scienc

    Candidate markers for stratification and classification in rheumatoid arthritis

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    Rheumatoid arthritis (RA) is a chronic autoimmune, inflammatory disease, characterized by synovitis in small- and medium-sized joints and, if not treated early and efficiently, joint damage, and destruction. RA is a heterogeneous disease with a plethora of treatment options. The pro-inflammatory cytokine tumor necrosis factor (TNF) plays a central role in the pathogenesis of RA, and TNF inhibitors effectively repress inflammatory activity in RA. Currently, treatment decisions are primarily based on empirics and economic considerations. However, the considerable interpatient variability in response to treatment is a challenge. Markers for a more exact patient classification and stratification are lacking. The objective of this study was to identify markers in immune cell populations that distinguish RA patients from healthy donors with an emphasis on TNF signaling. We employed mass cytometry (CyTOF) with a panel of 13 phenotyping and 10 functional markers to explore signaling in unstimulated and TNF-stimulated peripheral blood mononuclear cells from 20 newly diagnosed, untreated RA patients and 20 healthy donors. The resulting high-dimensional data were analyzed in three independent analysis pipelines, characterized by differences in both data clean-up, identification of cell subsets/clustering and statistical approaches. All three analysis pipelines identified p-p38, IkBa, p-cJun, p-NFkB, and CD86 in cells of both the innate arm (myeloid dendritic cells and classical monocytes) and the adaptive arm (memory CD4+ T cells) of the immune system as markers for differentiation between RA patients and healthy donors. Inclusion of the markers p-Akt and CD120b resulted in the correct classification of 18 of 20 RA patients and 17 of 20 healthy donors in regression modeling based on a combined model of basal and TNF-induced signal. Expression patterns in a set of functional markers and specific immune cell subsets were distinct in RA patients compared to healthy individuals. These signatures may support studies of disease pathogenesis, provide candidate markers for response, and non-response to TNF inhibitor treatment, and aid the identification of future therapeutic targets.publishedVersio

    Titrating complex mass cytometry panels

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    We describe here a simple and efficient antibody titration approach for cell‐surface markers and intracellular cell signaling targets for mass cytometry. The iterative approach builds upon a well‐characterized backbone panel of antibodies and analysis using bioinformatic tools such as SPADE. Healthy peripheral blood and bone marrow cells are stained with a pre‐optimized “backbone” antibody panel in addition to the progressively diluted (titrated) antibodies. Clustering based on the backbone panel enables the titration of each antibody against a rich hematopoietic background and assures that nonspecific binding and signal spillover can be quantified accurately. Using a slightly expanded backbone panel, antibodies quantifying changes in transcription factors and phosphorylated antigens are titrated on ex vivo stimulated cells to optimize sensitivity and evaluate baseline expression. Based on this information, complex panels of antibodies can be thoroughly optimized for use on healthy whole blood and bone marrow and are easily adaptable to the investigation of samples from for example clinical studies.publishedVersio

    Human immunodeficiency virus and hepatitis C virus/hepatitis B virus co-infection in Southern Brazil: clinical and epidemiological evaluation

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    AbstractHepatitis B virus, hepatitis C virus and human immunodeficiency virus share a similar transmission pathway and are often diagnosed in the same patient. These patients tend to have a faster progression of hepatic fibrosis. This cross-sectional study describes the demographic features and clinical profile of human immunodeficiency virus/hepatitis co-infected patients in Paraná, Southern Brazil. A total of 93 human immunodeficiency virus-infected patients attending a tertiary care academic hospital in Southern Brazil were included. Clinical, demographic and epidemiological data were evaluated. Hepatitis B virus and/or hepatitis C virus positive serology was found in 6.6% of patients. The anti-hepatitis C virus serum test was positive in 85% (79/93) of patients, and the infection was confirmed in 72% of the cases. Eighteen patients (19%) were human immunodeficiency virus/hepatitis B virus positive (detectable HBsAg). Among co-infected patients, there was a high frequency of drug use, and investigations for the detection of co-infection were conducted late. A low number of patients were eligible for treatment and, although the response to antiretroviral therapy was good, there was a very poor response to hepatitis therapy. Our preliminary findings indicate the need for protocols aimed at systematic investigation of hepatitis B virus and hepatitis C virus in human immunodeficiency virus-infected patients, thus allowing for early detection and treatment of co-infected patients
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