183 research outputs found

    ADDITIVE MANUFACTURING WITH LIQUID LATEX AND RECYCLED END-OF-LIFE RUBBER

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    Elastomers and rubber are common industrial materials used for test objects, supporting parts, and many other commercial products. The industrial processing of these materials is currently dominated by injection molding, which reduces manufacturing costs and speeds up production. However, this manufacturing method does not permit personalization or customization and lacks the versatility of other techniques such as three-dimensional printing. Understandably, there has been a move toward additive manufacturing (AM) with elastomers. This work proposes a new approach to AM with liquid latex, using a drop-on-demand (DoD) based inkjet to fabricate latex patterns. The printhead actuator benefits from a higher material compatibility compared to conventional inkjet/extrusion-based printers, allowing the jetting of viscous fluids, as well as liquids with high solid loading. The setup allows printing with viscous liquid latex of a high solid content (60 wt. %). The process is controllable and reliable, making the printing of patterns possible. In addition, we explore printing with micronized rubber powder (MRP) made from end-of-life tires, to test solid-particle loading compatibility and as a novel method for rubber recycling. In this study, we demonstrate that large-scale DoD inkjet printing is capable of handling solid particle loadings of up to 10 wt. % in addition to the high solid content liquid latex. Moreover, multilayer objects were created from pure liquid latex, as well as from MRP/latex suspensions. Material characterization indicates that the stiffness of cured latex is not altered by the addition of MRP, but reduces the maximum elongation length from 750% to 430%. The results highlight the ability to print with both high particle loading and large particles. This explorative study demonstrates the potential of AM processes with liquid latex, as well as a new approach to tire rubber reuse

    Raman spectroscopy for accurately characterizing biomolecular changes in androgen-independent prostate cancer cells

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    © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Metastatic prostate cancer resistant to hormonal manipulation is considered the advanced stage of the disease and leads to most cancer-related mortality. With new research focusing on modulating cancer growth, it is essential to understand the biochemical changes in cells that can then be exploited for drug discovery and for improving responsiveness to treatment. Raman spectroscopy has a high chemical specificity and can be used to detect and quantify molecular changes at the cellular level. Collection of large data sets generated from biological samples can be employed to form discriminatory algorithms for detection of subtle and early changes in cancer cells. The present study describes Raman finger printing of normal and metastatic hormone-resistant prostate cancer cells including analyses with principal component analysis and linear discrimination. Amino acid-specific signals were identified, especially loss of arginine band. Androgen-resistant prostate cancer cells presented a higher content of phenylalanine, tyrosine, DNA and Amide III in comparison to PNT2 cells, which possessed greater amounts of L-arginine and had a B conformation of DNA. The analysis utilized in this study could reliably differentiate the 2 cell lines (sensitivity 95%; specificity 88%)

    Pregnant women become insensitive to cold stress

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    BACKGROUND: The function of the hypothalamic-pituitary-adrenal (HPA) axis is known to be altered during pregnancy, but it has not been tested with a natural stressor. METHODS: A group of pregnant women (n = 10) were tested towards the end of pregnancy (mean 36.8 ± 2.5 weeks gestation) and about 8 weeks postpartum (mean 7.8 ± 1.5 weeks), together with a matched control group, with a one minute cold hand stressor test. Saliva samples were collected before and 10 and 20 minutes after the test, and stored for later radioimmunoassay of cortisol. RESULTS: The control group showed a highly significant response to the test. The pregnant group showed no response, and the postpartum group a variable but non significant one CONCLUSIONS: This shows that the HPA axis becomes hypofunctional to a natural stressor at the end of pregnancy. It is suggested that one possible evolutionary function for this is to protect the fetus from the stress responses of the mother

    The potential for immunoglobulins and host defense peptides (HDPs) to reduce the use of antibiotics in animal production

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    Abstract Innate defense mechanisms are aimed at quickly containing and removing infectious microorganisms and involve local stromal and immune cell activation, neutrophil recruitment and activation and the induction of host defense peptides (defensins and cathelicidins), acute phase proteins and complement activation. As an alternative to antibiotics, innate immune mechanisms are highly relevant as they offer rapid general ways to, at least partially, protect against infections and enable the build-up of a sufficient adaptive immune response. This review describes two classes of promising alternatives to antibiotics based on components of the innate host defense. First we describe immunoglobulins applied to mimic the way in which they work in the newborn as locally acting broadly active defense molecules enforcing innate immunity barriers. Secondly, the potential of host defense peptides with different modes of action, used directly, induced in situ or used as vaccine adjuvants is described

    Characterization of cytochrome P450 monooxygenase CYP154H1 from the thermophilic soil bacterium Thermobifida fusca

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    Cytochrome P450 monooxygenases are valuable biocatalysts due to their ability to hydroxylate unactivated carbon atoms using molecular oxygen. We have cloned the gene for a new cytochrome P450 monooxygenase, named CYP154H1, from the moderately thermophilic soil bacterium Thermobifida fusca. The enzyme was overexpressed in Escherichia coli at up to 14% of total soluble protein and purified to homogeneity in three steps. CYP154H1 activity was reconstituted using putidaredoxin reductase and putidaredoxin from Pseudomonas putida DSM 50198 as surrogate electron transfer partners. In biocatalytic reactions with different aliphatic and aromatic substrates of varying size, the enzyme converted small aromatic and arylaliphatic compounds like ethylbenzene, styrene, and indole. Furthermore, CYP154H1 also accepted different arylaliphatic sulfides as substrates chemoselectively forming the corresponding sulfoxides and sulfones. The enzyme is moderately thermostable with an apparent melting temperature of 67°C and exhibited still 90% of initial activity after incubation at 50°C

    A study of Docetaxel-induced effects in MCF-7 cells by means of Raman microspectroscopy

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    Chemotherapies feature a low success rate of about 25%, and therefore, the choice of the most effective cytostatic drug for the individual patient and monitoring the efficiency of an ongoing chemotherapy are important steps towards personalized therapy. Thereby, an objective method able to differentiate between treated and untreated cancer cells would be essential. In this study, we provide molecular insights into Docetaxel-induced effects in MCF-7 cells, as a model system for adenocarcinoma, by means of Raman microspectroscopy combined with powerful chemometric methods. The analysis of the Raman data is divided into two steps. In the first part, the morphology of cell organelles, e.g. the cell nucleus has been visualized by analysing the Raman spectra with k-means cluster analysis and artificial neural networks and compared to the histopathologic gold standard method hematoxylin and eosin staining. This comparison showed that Raman microscopy is capable of displaying the cell morphology; however, this is in contrast to hematoxylin and eosin staining label free and can therefore be applied potentially in vivo. Because Docetaxel is a drug acting within the cell nucleus, Raman spectra originating from the cell nucleus region were further investigated in a next step. Thereby we were able to differentiate treated from untreated MCF-7 cells and to quantify the cell–drug response by utilizing linear discriminant analysis models

    Rationale, design and methodology of a double-blind, randomized, placebo-controlled study of escitalopram in prevention of Depression in Acute Coronary Syndrome (DECARD)

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    <p>Abstract</p> <p>Background</p> <p>The prevalence of depression in patients with acute coronary syndrome, i.e. myocardial infarction and unstable angina, is higher than in the general population. The prevalence of anxiety is higher as well. Both depression and anxiety are associated with poor cardiac outcomes and higher mortality. Comorbid depression in patients with acute coronary syndrome often goes undiagnosed, and it is therefore a challenging task to prevent this risk factor. The study of DEpression in Coronary ARtery Disease (DECARD) is designed to examine if it is possible to prevent depression in patients with acute coronary syndrome.</p> <p>Methods</p> <p>Two hundred forty non-depressed patients with acute coronary syndrome are randomized to treatment with either escitalopram or placebo for 1 year. Psychiatric and cardiac assessment of patients is performed to evaluate the possibility of preventing depression. Diagnosis of depression and Hamilton Depression Scale are the primary outcome measures.</p> <p>Discussion</p> <p>This is the first study of prevention of depression in patients after acute coronary syndrome with a selective serotonin reuptake inhibitor.</p> <p>Trial Registration</p> <p><url>http://www.ClinicalTrials.gov.</url> Identifier: NCT00140257</p

    Protocol for take-home naloxone In multicentre emergency (TIME) settings: Feasibility study

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    Background: Opioids, such as heroin, kill more people worldwide by overdose than any other type of drug, and death rates associated with opioid poisoning in the UK are at record levels (World Drug Report 2018 [Internet]. [cited 2019 Nov 19]. Available from: http://www.unodc.org/wdr2018/; Deaths related to drug poisoning in England and Wales - Office for National Statistics [Internet]. [cited 2019 Nov 19]. Available from: https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/deaths/bulletins/deathsrelatedtodrugpoisoninginenglandandwales/2018registrations). Naloxone is an opioid antagonist which can be distributed in 'kits' for administration by witnesses in an overdose emergency. This intervention is known as take-home naloxone (THN). We know that THN can save lives on an individual level, but there is currently limited evidence about the effectiveness of THN distribution on an aggregate level, in specialist drug service settings or in emergency service settings. Notably, we do not know whether THN kits reduce deaths from opioid overdose in at-risk populations, if there are unforeseen harms associated with THN distribution or if THN is cost-effective. In order to address this research gap, we aim to determine the feasibility of a fully powered cluster randomised controlled trial (RCT) of THN distribution in emergency settings. Methods: We will carry out a feasibility study for a RCT of THN distributed in emergency settings at four sites, clustered by Emergency Department (ED) and catchment area within its associated ambulance service. THN is a peer-administered intervention. At two intervention sites, emergency ambulance paramedics and ED clinical staff will distribute THN to adult patients who are at risk of opioid overdose. At two control sites, practice will carry on as usual. We will develop a method of identifying a population to include in an evaluation, comprising people at risk of fatal opioid overdose, who may potentially receive naloxone included in a THN kit. We will gather anonymised outcomes up to 1 year following a 12-month 'live' trial period for patients at risk of death from opioid poisoning. We expect approximately 100 patients at risk of opioid overdose to be in contact with each service during the 1-year recruitment period. Our outcomes will include deaths, emergency admissions, intensive care admissions, and ED attendances. We will collect numbers of eligible patients attended by participating in emergency ambulance paramedics and attending ED, THN kits issued, and NHS resource usage. We will determine whether to progress to a fully powered trial based on pre-specified progression criteria: sign-up of sites (n = 4), staff trained (≥ 50%), eligible participants identified (≥ 50%), THN provided to eligible participants (≥ 50%), people at risk of death from opioid overdose identified for inclusion in follow-up (≥ 75% of overdose deaths), outcomes retrieved for high-risk individuals (≥ 75%), and adverse event rate (< 10% difference between study arms). Discussion: This feasibility study is the first randomised, methodologically robust investigation of THN distribution in emergency settings. The study addresses an evidence gap related to the effectiveness of THN distribution in emergency settings. As this study is being carried out in emergency settings, obtaining informed consent on behalf of participants is not feasible. We therefore employ novel methods for identifying participants and capturing follow-up data, with effectiveness dependent on the quality of the available routine data
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