1,251 research outputs found

    Gel point in CNC dispersion from FT Rheology

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    A non-linear analysis via Fourier-Transform Rheology (FT-Rheology) and Large Ampli- tude Oscillatory Shear (LAOS) of cellulose nanocrystals (CNC) dispersions is presented. Dynamic frequency and strain sweep measure- ments were performed for different CNC con- centrations with various parameters (w , g ). The relevance of nonlinear material rheological pa- rameters on flow-field-CNC interactions are initially investigated. This preliminary analy- sis is mainly formed on the magnitude of the stress response nonlinearities. Dependence of concentration on phase transition in CNC while applying strain was investigated. A comparison between the linear viscoelastic dynamic moduli and nonlinearities a steep increase in nonlinear response around the gel point

    Spatiotemporal perspectives on urban energy transitions: a comparative study of three cities in China

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    This paper develops an integrated framework to study the socio-spatial and temporal dimensions of urban energy transitions to investigate the development and spread of solar energy technologies in urban China. A comparative analysis of three case studies of solar energy transitions in the cities of Foshan (in Guangdong), Rizhao (in Shandong), and Wuxi (in Jiangsu) demonstrates the framework’s applicability. The results map each city’s trajectory towards low carbon energy. Transitions result from dynamic interactions among central and local governments, solar manufacturers, solar installers, and residents. Alongside industrial strategies, locally-specific factors have a determining influence on the eventual outcomes

    Phase transitions of cellulose nanocrystal suspensions from nonlinear oscillatory shear

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    Cellulose nanocrystals (CNCs) self- assemble in water suspensions into liquid crystalline assemblies. Here, we elucidate the microstructural changes associated with nonlinear deformations in (2–9 wt%) CNC suspensions through nonlinear rheological analysis, that was performed in paral- lel with coupled rheology—polarized light imaging. We show that nonlinear material parameters from Fourier-transform rheology and stress decomposition are sensitive to all CNC phases investigated, i.e. iso- tropic, biphasic and liquid crystalline. This is in con- trast to steady shear and linear viscoelastic dynamic moduli where the three-region behavior and weak strain overshoot cannot distinguish between biphasic and liquid crystalline phases. Thus, the inter-cycle and intra-cycle nonlinear parameters investigated are a more sensitive approach to relate rheological meas- urements to CNC phase behavior

    Isotropic Gels of Cellulose Nanocrystals Grafted with Dialkyl Groups: Influence of Surface Group Topology from Nonlinear Oscillatory Shear

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    Attractive (non-self-assembling) aqueous cellulose nanocrystal (CNC) suspensions were topologically tailored into isotropic gels through the surface grafting of dialkyl groups. We thus focus on the influence of CNC concentration, including for pristine CNC, surface linker branching, branching degree, and the influence of side group size and branch-on-branch surface-grafted groups. The resulting mobility and strength of interaction in particle-particle interaction mediated by the surface groups was investigated from a rheological point of view. The emphasis is on nonlinear material parameters from Fourier-transform rheology and stress decomposition analysis. The results show that nonlinear material parameters are more sensitive than linear viscoelastic parameters to the onset of weakly interconnected networks in pristine CNC isotropic suspensions. All surface-modified CNC suspensions resulted in isotropic gels. The nonlinear material parameters were found to be broadly sensitive to CNC concentration, branching, degree of branching and surface-grafted linkers’ length. However, the length of the grafted chains and the degree of branching were the primary factors influencing the nonlinear material response. Furthermore, the results showed evidence of two strain amplitude ranges with distinct nonlinear signatures that could be attributed to the disruption of weak network connection points and to distortions of more dense (aggregate) network regions, respectively

    Assessing an online patient decision aid about upper extremity reconstructive surgery for cervical spinal cord injury: Pilot testing knowledge, decisional conflict, and acceptability

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    UNLABELLED: HIGHLIGHTS: People with cervical spinal cord injury prioritize gaining upper extremity function after injury, but few individuals receive information about treatment options.A newly created patient decision aid (PtDA) provides information about recovery after spinal cord injury and the role of traditional tendon and newer nerve transfer surgery to improve upper extremity upper extremity function.The PtDA improved knowledge and decreased decisional conflict in this pilot study.Future work should focus on studying dissemination and implementation of the ptDA into clinical practice

    Comparison of a reduced carbohydrate and reduced fat diet for LDL, HDL, and VLDL subclasses during 9-months of weight maintenance subsequent to weight loss

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    Objectives: This study compared LDL, HDL, and VLDL subclasses in overweight or obese adults consuming either a reduced carbohydrate (RC) or reduced fat (RF) weight maintenance diet for 9 months following significant weight loss. Methods: Thirty-five (21 RC; 14 RF) overweight or obese middle-aged adults completed a 1-year weight management clinic. Participants met weekly for the first six months and bi-weekly thereafter. Meetings included instruction for diet, physical activity, and behavior change related to weight management. Additionally, participants followed a liquid very low-energy diet of ~2092 kJ per day for the first three months of the study. Subsequently, participants followed a dietary plan for nine months that targeted a reduced percentage of carbohydrate (~20%) or fat (~30%) intake and an energy intake level calculated to maintain weight loss. Lipid subclasses using NMR spectroscopy were analyzed prior to weight loss and at multiple intervals during weight maintenance. Results: Body weight change was not significantly different within or between groups during weight maintenance (p > 0.05). The RC group showed significant increases in mean LDL size, large LDL, total HDL, large and small HDL, mean VLDL size, and large VLDL during weight maintenance while the RF group showed increases in total HDL, large and small HDL, total VLDL, and large, medium, and small VLDL (p 0.05). Conclusion: Some individual lipid subclasses improved in both dietary groups. Large and medium VLDL subclasses increased to a greater extent across weight maintenance in the RF group

    Cerebrospinal fluid biomarkers of brain injury, inflammation and synaptic autoimmunity predict long-term neurocognitive outcome in herpes simplex encephalitis

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    OBJECTIVES: To investigate the correlation between biomarkers of brain injury and long-term neurocognitive outcome, and the interplay with intrathecal inflammation and neuronal autoimmunity, in patients with herpes simplex encephalitis (HSE). METHODS: A total of 53 adult/adolescent HSE patients were included from a prospective cohort in a randomized placebo-controlled trial investigating the effect of a 3-month follow-up treatment with valaciclovir. Study subjects underwent repeated serum/CSF sampling and brain MRI the first 3 months along with cognitive assessment by Mattis Dementia Rating Scale (MDRS) during 24 months. CSF samples were analyzed for biomarkers of brain injury, inflammation and synaptic autoimmunity. The pre-defined primary analysis was the correlation between peak CSF neurofilament protein (NFL), a biomarker of neuronal damage, and MDRS at 24 months. RESULTS: Impaired cognitive performance significantly correlated with NFL levels (rho = -0.36, p = 0.020). Development of IgG anti-N-methyl-D-aspartate receptor (NDMAR) antibodies was associated with a broad and prolonged proinflammatory CSF response. In a linear regression model, lower MDRS at 24 months was associated with previous development of IgG anti-NMDAR (beta = -0.6249, p = 0.024) and age (z-score beta = -0.2784, p = 0.024), but not CSF NFL, which however significantly correlated with subsequent NMDAR autoimmunization (p = 0.006). CONCLUSIONS: Our findings show that NFL levels are predictive of long-term neurocognitive outcome in HSE, and suggest a causative chain of events where brain tissue damage increases the risk of NMDAR autoimmunisation and subsequent prolongation of CSF inflammation. The data provides guidance for a future intervention study of immunosuppressive therapy administered in the recovery phase of HSE
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