Dual Band Electrodes in Generator-Collector Mode: Simultaneous Measurement of Two Species

A computational model for the simulation of a double band collector-generator experiment is applied to the situation where two electrochemical reactions occur concurrently. It is shown that chronoamperometric measurements can be used to take advantage of differences in diffusion coefficients to measure the concentrations of both electroactive species simultaneously, by measuring the time at which the collection efficiency reaches a specific value. The separation of the electrodes is shown to not affect the sensitivity of the method (in terms of percentage changes in the measured time to reach the specified collection efficiency), but wider gaps can provide a greater range of (larger) absolute values of this characteristic time. It is also shown that measuring the time taken to reach smaller collection efficiencies can allow for the detection of smaller amounts of whichever species diffuses faster. The case of a system containing both ascorbic acid and opamine in water is used to exemplify the method, and it is shown that mole fractions of ascorbic acid between 0.055 and 0.96 can, in principle, be accurately measured.Comment: 34 pages, 8 figure

Photo Inactivation of Streptococcus mutans Biofilm by Violet-Blue light

Among various preventive approaches, non-invasive phototherapy/photodynamic therapy is one of the methods used to control oral biofilm. Studies indicate that light at specific wavelengths has a potent antibacterial effect. The objective of this study was to determine the effectiveness of violet-blue light at 380-440 nm to inhibit biofilm formation of Streptococcus mutans or kill S. mutans. S. mutans UA159 biofilm cells were grown for 12-16 h in 96-well flat-bottom microtiter plates using tryptic soy broth (TSB) or TSB with 1 % sucrose (TSBS). Biofilm was irradiated with violet-blue light for 5 min. After exposure, plates were re-incubated at 37 °C for either 2 or 6 h to allow the bacteria to recover. A crystal violet biofilm assay was used to determine relative densities of the biofilm cells grown in TSB, but not in TSBS, exposed to violet-blue light. The results indicated a statistically significant (P < 0.05) decrease compared to the non-treated groups after the 2 or 6 h recovery period. Growth rates of planktonic and biofilm cells indicated a significant reduction in the growth rate of the violet-blue light-treated groups grown in TSB and TSBS. Biofilm viability assays confirmed a statistically significant difference between violet-blue light-treated and non-treated groups in TSB and TSBS. Visible violet-blue light of the electromagnetic spectrum has the ability to inhibit S. mutans growth and reduce the formation of S. mutans biofilm. This in vitro study demonstrated that violet-blue light has the capacity to inhibit S. mutans biofilm formation. Potential clinical applications of light therapy in the future remain bright in preventing the development and progression of dental caries

Development of a behaviour change intervention to encourage timely cancer symptom presentation among people living in deprived communities using the Behaviour Change Wheel

We are grateful to the National Awareness and Early Diagnosis Initiative (NAEDI) for funding this work. The NAEDI funding consortium, under the auspices of the National Cancer Research Institute (NCRI), consists of Cancer Research UK; Department of Health (England); Economic and Social Research Council; Health and Social Care R&D Division, Public Health Agency (Northern Ireland); National Institute for Social Care and Health Research (Wales); and the Scottish Government. We would like to thank ABACus project management team members Tim Banks and Maura Matthews from Tenovus Cancer Care for their ongoing support and involvement in the project. The authors would also like to acknowledge the support of the ABACus steering group (Danny Antebi, Tracey Deacon, Karen Gully, Jane Hanson, Sharon Hillier, Alex Murray, Richard Neal, Gill Richardson, Mark Rogers, and Sara Thomas). Compliance with Ethical StandardsPeer reviewedPublisher PD

Porcine reproductive and respiratory syndrome virus (PRRSV) infection spreads by cell-to-cell transfer in cultured MARC-145 cells, is dependent on an intact cytoskeleton, and is suppressed by drug-targeting of cell permissiveness to virus infection

BACKGROUND: Porcine reproductive and respiratory syndrome virus (PRRSV) is the etiologic agent of PRRS, causing widespread chronic infections which are largely uncontrolled by currently available vaccines or other antiviral measures. Cultured monkey kidney (MARC-145) cells provide an important tool for the study of PRRSV replication. For the present study, flow cytometric and fluorescence antibody (FA) analyses of PRRSV infection of cultured MARC-145 cells were carried out in experiments designed to clarify viral dynamics and the mechanism of viral spread. The roles of viral permissiveness and the cytoskeleton in PRRSV infection and transmission were examined in conjunction with antiviral and cytotoxic drugs. RESULTS: Flow cytometric and FA analyses of PRRSV antigen expression revealed distinct primary and secondary phases of MARC-145 cell infection. PRRSV antigen was randomly expressed in a few percent of cells during the primary phase of infection (up to about 20–22 h p.i.), but the logarithmic infection phase (days 2–3 p.i.), was characterized by secondary spread to clusters of infected cells. The formation of secondary clusters of PRRSV-infected cells preceded the development of CPE in MARC-145 cells, and both primary and secondary PRRSV infection were inhibited by colchicine and cytochalasin D, demonstrating a critical role of the cytoskeleton in viral permissiveness as well as cell-to-cell transmission from a subpopulation of cells permissive for free virus to secondary targets. Cellular expression of actin also appeared to correlate with PRRSV resistance, suggesting a second role of the actin cytoskeleton as a potential barrier to cell-to-cell transmission. PRRSV infection and cell-to-cell transmission were efficiently suppressed by interferon-γ (IFN-γ), as well as the more-potent experimental antiviral agent AK-2. CONCLUSION: The results demonstrate two distinct mechanisms of PRRSV infection: primary infection of a relatively small subpopulation of innately PRRSV-permissive cells, and secondary cell-to-cell transmission to contiguous cells which appear non-permissive to free virus. The results also indicate that an intact cytoskeleton is critical for PRRSV infection, and that viral permissiveness is a highly efficient drug target to control PRRSV infection. The data from this experimental system have important implications for the mechanisms of PRRSV persistence and pathology, as well as for a better understanding of arterivirus regulation

Interdigitated ring electrodes: Theory and experiment

The oxidation of potassium ferrocyanide, K_4Fe(CN)_6, in aqueous solution under fully supported conditions is carried out at interdigitated band and ring electrode arrays, and compared to theoretical models developed to simulate the processes. Simulated data is found to fit well with experimental results using literature values of diffusion coefficients for Fe(CN)_6^(4-) and Fe(CN)_6^(3-). The theoretical models are used to compare responses from interdigitated band and ring arrays, and the size of ring array required to approximate the response to a linear band array is investigated. An equation is developed for the radius of ring required for a pair of electrodes in a ring array to give a result with 5% of a pair of electrodes in a band array. This equation is found to be independent of the scan rate used over six orders of magnitude

Engineered 3D tissue models for cell-laden microfluidic channels

Abstract Delivery of nutrients and oxygen within threedimensional (3D) tissue constructs is important to maintain cell viability. We built 3D cell-laden hydrogels to validate a new tissue perfusion model that takes into account nutrition consumption. The model system was analyzed by simulating theoretical nutrient diffusion into cell-laden hydrogels. We carried out a parametric study considering different microchannel sizes and inter-channel separation in the hydrogel. We hypothesized that nutrient consumption needs to be taken into account when optimizing the perfusion channel size and separation. We validated the hypothesis by experiments. We fabricated circular microchannels (r= 400 μm) in 3D cell-laden hydrogel constructs (R = 7.5 mm, volume=5 ml). These channels were positioned either individually or in parallel within hydrogels to increase nutrient and oxygen transport as a way to improve cell viability. We quantified the spatial distribution of viable cells within 3D hydrogel scaffolds without channels and with single-and dual-perfusion microfluidic channels. We investigated quantitatively the cell viability as a function of radial distance from the channels using experimental data and mathematical modeling of diffusion profiles. Our simulations show that a large-channel radius as well as a large channel to channel distance diffuse nutrients farther through a 3D hydrogel. This is important since our results reveal that there is a close correlation between nutrient profiles and cell viability across the hydrogel

Endothelial Cell Processing and Alternatively Spliced Transcripts of Factor VIII: Potential Implications for Coagulation Cascades and Pulmonary Hypertension

Background: Coagulation factor VIII (FVIII) deficiency leads to haemophilia A. Conversely, elevated plasma levels are a strong predictor of recurrent venous thromboemboli and pulmonary hypertension phenotypes in which in situ thromboses are implicated. Extrahepatic sources of plasma FVIII are implicated, but have remained elusive. Methodology/Principal Findings: Immunohistochemistry of normal human lung tissue, and confocal microscopy, flow cytometry, and ELISA quantification of conditioned media from normal primary endothelial cells were used to examine endothelial expression of FVIII and coexpression with von Willebrand Factor (vWF), which protects secreted FVIII heavy chain from rapid proteloysis. FVIII transcripts predicted from database mining were identified by rt-PCR and sequencing. FVIII mAb-reactive material was demonstrated in CD31+ endothelial cells in normal human lung tissue, and in primary pulmonary artery, pulmonary microvascular, and dermal microvascular endothelial cells. In pulmonary endothelial cells, this protein occasionally colocalized with vWF, centered on Weibel Palade bodies. Pulmonary artery and pulmonary microvascular endothelial cells secreted low levels of FVIII and vWF to conditioned media, and demonstrated cell surface expression of FVIII and vWF Ab–reacting proteins compared to an isotype control. Four endothelial splice isoforms were identified. Two utilize transcription start sites in alternate 59 exons within the int22h-1 repeat responsible for intron 2

Brexit and the work-family conflict:a Scottish perspective

This paper examines the Scottish Government’s desire to maintain ties with EU law post-Brexit in the context of employment and equality law, particularly those laws which impact on work-family conflict. The paper critically examines whether there is, or could be, a distinctly Scottish perspective in the context of work-family rights post-Brexit. The paper frames the analysis by considering the potentially gendered implications of Brexit in this context. In doing so, it examines this issue from the perspective of traditional heterosexual dual-partnered working family models. It is argued that rights for working fathers will be most vulnerable post-Brexit, with related consequences for working mothers. Consequently, the implications of Brexit in this context are primarily viewed through the lens of working fathers. The paper then critically examines the Scottish Government’s position on EU employment and equality law in the post-Brexit context

Occupational Safety and Health Practices among Physical Therapists in Metro Manila during the COVID-19 Pandemic: A Qualitative Study Protocol

Introduction: The purpose of Occupational Safety and Health (OSH) is to protect and prevent workers from being exposed to risks and hazards that are detrimental to their health and safety. For the past two years, the coronavirus disease 2019 (COVID-19) is one of the most significant occupational health outcomes to physical therapists (PTs) due to the nature of their work. However, minimal studies have been conducted about the experiences and OSH practices of PTs during the pandemic. This study aims to understand the experiences of clinical PTs in Metro Manila, Philippines during the pandemic. The study also seeks to explore the OSH practices and responses of PTs to presenting occupational risks and hazards through a qualitative descriptive study design. Methods: In this qualitative descriptive study, a maximum variation purposeful sampling method will be used in recruiting an estimated total of twelve (12) participants. A preliminary questionnaire would be disseminated via Google Forms to determine the eligibility of potential participants. Data will be gathered through a one-to-one semi-structured online interview, which will be transcribed verbatim and recorded with audio and video. Both manual coding and software-aided coding (NVivo) will be utilized in the data analysis. Emerging themes will be identified using thematic inductive analysis. Discussion: The results of the study may contribute to the formulation of better guidelines in handling infectious diseases even after quarantine restrictions are lifted. Furthermore, the findings will also provide the groundwork for the local body of knowledge in the Philippines and may serve as a future reference for research concerning OSH practices in physical therapy locally