Nonlinearity in Large Amplitude Oscillatory Shear (Laos) of Different Viscoelastic Materials

The present work investigates nonlinear behavior in large amplitude oscillatory shear (LAOS) of four different polymeric materials using simultaneous conventional rheometric measurements and particle-tracking velocimetric observations. In contrast to most studies in the literature that treat nonlinearity in LAOS in steady state, we emphasize by the present four examples that nonlinearity in LAOS often arise in complex fluids due to time-dependent rearrangement of their microstructures in response to LAOS. Consequently, no correlation is obvious between strain dependence of the steady-state stress response and the time-dependent characteristics of the steady-state response. For instance, a highly viscoelastic material made of nano-sized polybutadiene particles exhibits homogeneous deformation and an approximate sinusoidal wave despite strong strain softening. In a second example, a well-entangled polybutadiene solution becomes inhomogeneous over time, and the corresponding nonlinearity (i.e., strain softening) took a finite time to develop to its fullest. In the example of wall slip of a monodisperse entangled polyisoprene melt, contrary to the literature claim that even harmonics would emerge, we show that the stress response only involves odd harmonics in the absence of any edge fracture. Last, a polydisperse poly(dimethyl siloxane) melt experiences homogeneous LAOS without displaying significant higher harmonics in the absence of any edge failure. In contrast, the Fourier transform analysis shows that meniscus failure is responsible for the emergence of higher harmonics including some even ones. (C) 2009 The Society of Rheology. [DOI: 10.1122/1.3193713

Incentives, Positive Emotions and SWOM Intention: Moderating Roles of Allocation Type and Emotion Regulation

With the increasing popularity of social networking sites (SNS), companies are adopting monetary incentives to generate eWOM on SNS (SWOM). Drawing on emotion and equity theories, this study explores effects of perceived magnitude of monetary incentives and emotions on consumer SWOM intention. In addition, this study investigates the moderating effects of allocation types of rewards (positive inequity and negative inequity) and emotion regulation (reappraisal and suppression emotion regulation) on these relationships. An online situational experiment was conducted and yielded valid responses from 193 WeChat users in China. With the preliminary data, we tested the direct, mediation, and moderation effects using SmartPLS 3.0. The empirical results show that (1) perceived monetary incentives have a positive effect on SWOM intention; (2) positive emotions of senders mediates the relationship between incentives and SWOM intention; (3) negative-inequity incentives negatively moderates the relationship between incentives and positive emotion, while the moderating effect of positive-inequity incentives is insignificant on the relationship between incentives and positive emotion; (4) reappraisal emotion regulation strengthens the effect of positive emotion on SWOM intention, whereas the moderating effect of suppression emotion regulation between positive emotion and SWOM intention is not statistically significant

Primary cell culture of meningothelial cells—a new model to study the arachnoid in glaucomatous optic neuropathy

Background: In a previous report, we found that the occurrence and amount of meningothelial cell nests in the subarachnoid space are significantly increased in glaucomatous optic nerves compared to normals. In order to allow research into the role of meningothelial cells during diseases of the optic nerve, an in vitro model is necessary. For this purpose, we developed a culture method for porcine meningothelial cells from the arachnoid layer covering the optic nerve. Methods: Meningothelial cells were scraped from the arachnoid layer of porcine optic nerves and cultured for 2-3weeks until the cells formed a monolayer. To eliminate contaminating fibroblasts from the culture, cells were negatively selected using magnetic anti-fibroblast beads after the first passage. Cells were detached using 0.05% Trypsin-EDTA, incubated with anti-fibroblast beads, separated using a magnetic column and the flow-through was collected. The purified primary meningothelial cells were characterized by electron microscopy and immunocytochemistry using anti-glial fibrillary acidic protein (GFAP) and anti-keratan sulfate antibodies. Results: Primary cells grew out after dissection and formed a monolayer within 2-3weeks, which was composed of two morphologically different cell types, flattened cells with round nuclei and fibroblast-like cells with long processes. The fibroblast-like cells in the culture could be labelled and selected using anti-fibroblast microbeads. The second cell type did not bind to the anti-fibroblast beads, and upon immunocytochemistry showed a marked expression of both GFAP and keratan sulphate. In addition, examination of these cells by electron microscopy revealed morphological characteristics of meningothelial cells, including hemidesmosomes and cytoplasmatic filaments. Conclusions: The technique described in this paper for the primary culture of meningothelial cells from the subarachnoid space of the optic nerve and using magnetic beads for the removal of fibroblasts is effective in obtaining a highly enriched meningothelial cell cultur

L-PGDS (Betatrace Protein) Inhibits Astrocyte Proliferation and Mitochondrial ATP Production in Vitro

L-PGDS is the most abundant protein present in the cerebrospinal fluid (CSF). Although CSF was believed to be homogenous in content, a previous study has showed that a marked concentration gradient of L-PGDS exists between the spinal CSF and the CSF in the subarachnoid space of patients with optic nerve disease (papilledema and normal-tension glaucoma). Astrocytes play a critical role in maintaining the integrity of axon function in the central nervous system and specifically in the optic nerve, and we therefore investigated the biochemical effects of L-PGDS on the proliferation of astrocytes and on the production of adenosine triphosphate (ATP) by astrocyte mitochondria. We found an inhibitory effect of L-PGDS on both proliferation of astrocytes and production of astrocyte ATP. The concentrations that inhibited astrocyte proliferation and ATP production were in the range measured in patients with idiopathic intracranial hypertension and in patients with normal-tension glaucoma. As the CSF is in contact with axons and mitochondria of the optic nerve (Bristow et al. Archives of Ophthalmology, 120, 791-796, 2002), we postulate that a change in the concentration of CSF protein such as L-PGDS could exercise a harmful effect on these structure

Degradation of Toxic Organic Contaminants by Graphene Cathode in an Electro‐Fenton System

A novel composite electrode was constructed by pressing graphene and CuO, using a cathode in an electro‐Fenton (EF) system. Cyclic voltammetry, charge/discharge curve and electrochemical impedance spectroscopy (EIS) were used to characterize the composite electrode. The degradation of a toxic organic contaminant, Terramycin, by EF system was studied in an undivided electrolysis cell. The possible degradation products of Terramycin were studied by a Fourier transform‐infrared spectrum, and the findings showed that the structure of Terramycin was damaged. The variations of hydrogen peroxide and the relative content of hydroxyl radical (.OH) during the degradation process were traced by enzyme catalysis method and fluorescence spectrometry. The results showed that the electro‐catalytic degradation of Terramycin occurred by an ·OH radical mechanism. More importantly, this as‐prepared cathode was very stable and could be reused without any catalytic activity decrease, suggesting its potential application in the wastewater treatment

Receptors that bind to PEDF and their therapeutic roles in retinal diseases

Retinal neovascular, neurodegenerative, and inflammatory diseases represented by diabetic retinopathy are the main types of blinding eye disorders that continually cause the increased burden worldwide. Pigment epithelium-derived factor (PEDF) is an endogenous factor with multiple effects including neurotrophic activity, anti-angiogenesis, anti-tumorigenesis, and anti-inflammatory activity. PEDF activity depends on the interaction with the proteins on the cell surface. At present, seven independent receptors, including adipose triglyceride lipase, laminin receptor, lipoprotein receptor-related protein, plexin domain-containing 1, plexin domain-containing 2, F1-ATP synthase, and vascular endothelial growth factor receptor 2, have been demonstrated and confirmed to be high affinity receptors for PEDF. Understanding the interactions between PEDF and PEDF receptors, their roles in normal cellular metabolism and the response the initiate in disease will be accommodating for elucidating the ways in which inflammation, angiogenesis, and neurodegeneration exacerbate disease pathology. In this review, we firstly introduce PEDF receptors comprehensively, focusing particularly on their expression pattern, ligands, related diseases, and signal transduction pathways, respectively. We also discuss the interactive ways of PEDF and receptors to expand the prospective understanding of PEDF receptors in the diagnosis and treatment of retinal diseases

Polymorphism in a Plasmodium falciparum Erythrocyte-binding Ligand Changes Its Receptor Specificity

Recognition of human erythrocytes by Plasmodium species depends in part on Region II of the Duffy binding-like family of parasite ligands, which includes BA erythrocyte binding ligand (BAEBL) of P. falciparum. In previous studies of BAEBL from two clones, Dd2/Nm from Vietnam and E12 from Papua New Guinea (PNG), it was found that BAEBL bound different erythrocyte receptors. Because of variation in binding specificity, we studied the sequence and erythrocyte binding specificity of Region II of BAEBL in P. falciparum clones from different parts of the world. We observed five nucleotide substitutions leading to five amino acid changes and five polymorphisms in Region II of BAEBL in parasites from both PNG and other parts of the world. We expressed four of the polymorphisms on COS cells and determined their binding to enzyme-treated erythrocytes and to Gerbich-negative erythrocytes. We also performed erythrocyte-binding assay using the native protein from radiolabeled culture supernatant. Both assays demonstrated that each of the four polymorphisms in the parasite ligand, BAEBL, bound to a different receptor on erythrocytes. These results suggest that P. falciparum has evolved multiple invasion pathways dependent on polymorphisms in the BAEBL ligand

Life-Cycle Building Carbon Emission Management Platform based on Building Information Modeling Technology

Buildings produce 40% of annual carbon emissions among various sectors in modern society. One of the most challenging problems of carbon management is how to monitor and calculate a building’s life-cycle energy consumption and carbon emission data during both construction and operation stages. The Building Information Modeling (BIM) technology provides a promising method to obtain and simulate buildings as-is status at different stages in the life cycle. This paper develops a framework for building a carbon emission management platform using the carbon emission factor method and BIM technology, which can derive corresponding carbon emission and measure carbon footprint with building geographic information to achieve precise positioning of carbon emission objects. The platform can achieve multi-role collaboration, equipment visualization, real-time carbon emission monitoring, and data analysis. The platform is applied to an existing building in Hohai University to assess the total carbon footprint of the building in its life cycle. This platform can greatly improve the calculation accuracy of the carbon footprint of buildings, improve data transparency, provide valuable information for building facility management personnel, and help achieve the goal of carbon neutrality

High-performance chiral all-optical logic gate based on topological edge states of valley photonic crystal

For all-optical communication and information processing, it is necessary to develop all-optical logic gates based on photonic structures that can directly perform logic operations. All-optical logic gates have been demonstrated based on conventional waveguides and interferometry, as well as photonic crystal structures. Nonetheless, any defects in those structures will introduce high scattering loss, which compromises the fidelity and contrast ratio of the information process. Based on the spin-valley locking effect that can achieve defect-immune unidirectional transmission of topological edge states in valley photonic crystals (VPCs), we propose a high-performance all-optical logic OR gate based on a VPC structure. By tuning the working bandwidth of the two input channels, we prevent interference between the two channels to achieve a stable and high-fidelity output. The transmittance of both channels is higher than 0.8, and a high contrast ratio of 28.8 dB is achieved. Moreover, the chirality of the logic gate originated from the spin-valley locking effect allows using different circularly polarized light as inputs, representing "1" or "0", which is highly desired in quantum computing. The device's footprint is small, allowing high-density on-chip integration. In addition, this design can be experimentally fabricated using current nanofabrication techniques and will have potential applications in optical communication, information processing, and quantum computing.Comment: 10 pages, 6 figure