216 research outputs found

    The Experimental Investigation of The performance of Phosphor Coating

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    Different screen printing parameters have a distinct effect on the quality of coating that is created. This experimental work looked to measure these parameters. It is divided into two parts where the first part measured the surface wettability of various substrates Wettability measurement was performed through measuring the contact angle between the droplet and the substrate surface. Varying the UV exposure time by putting substrate in the UV ozone cleaner has a considerable effect on the wettability of the surface. Water was supplied to a PEDOT: PSS substrate via Fibro DAT 1100 which is attached to a camera and a computer for capturing and analyzing coatings for the spread of a water droplet on the substrate surface. From these analyses, the main aim is to measure the contact angle between the droplet and the substrate surface which indicates the surface wettability. Some factors may affect the wettability of the surface such as varying the UV time and varying the hold time. As a result, increasing these times will decrease the contact angle where a small contact angle indicates a favorable wettability. The second part measured the electrical resistance and transparency of the printed ink after various printing experiments such as implementing UV treatment, changing the ink and changing the mesh ruling. The Rheometer device was used to test the properties of the specimen. Where this device can be used to measure the properties of the specimen such as the shear modules, in this paper the plate was used to effect on the specimens, where different readings are recorded for these specimens. Also, 24 samples were prepared and the electrical resistance for these samples was measured in this paper. As a result, the electrical resistance for treated samples was greater than that for untreated samples; the electrical resistance of Elentan ink was greater than that for PEDOT at the same conditions. Changing the screen size from (61-64) to (40-100) increase the value of resistance at the same conditions. For the transparency measurements the Elentan ink had a higher transparency than PEDOT ink. The paper also carried out an analysis for the relation between the thickness of the phosphor layer and the lamp output, where the relation was inversely proportion

    A preliminary study on whether HbA1c levels can predict visual dependence for spatial orientation in asymptomatic Type 2 diabetic patients

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    Introduction: Diabetes-induced vestibular dysfunction has been commonly reported, and asymptomatic patients with type 2 diabetes display higher degrees of perceptual visual dependence for spatial orientation than healthy controls. This study aims to assess whether HbA1c can predict such visual dependence in the diabetic patients. Methods and Materials: Diabetic patients were divided into 2 groups: 22 subjects with “good” (HbA1c < 7%) and 25 with “poor” (HbA1c ≥ 7%) glycemic control. Otolithic vestibular function was tested using the computerized rod-and-frame test (CRFT) and results for the two diabetic groups were compared to 29 healthy controls. Results: When the frame was tilted, the diabetic group with “good” glycemic control had largest positioning errors, with a significant difference only in comparison to the control group. The “good” glycemic group exhibited larger degree of asymmetry under titled frame condition. Although HbA1c was not associated with vestibular asymmetry in any diabetic group, it was significantly associated with visual dependence in the “good” glycemic group. During frame tilts, 10 diabetic patients had positioning errors above the reference range of 3.3°, 8 of which belonged to the “good” glycemic diabetic group. Conclusions: Diabetes disease processes may affect vestibular symmetry during visuo-vestibular conflicts, even in asymptomatic diabetics within the recommended glycemic range. The weak correlations between HbA1c and CRFT parameters may indicate that HbA1c cannot fully predict visual dependence or asymmetry on the CRFT in patients with diabetes, and different glycemic disorders may affect vestibular dependent spatial orientation in diabetic patients

    European propolis is highly active against trypanosomatids including Crithidia fasciculata

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    Extracts of 35 samples of European propolis were tested against wild type and resistant strains of the protozoal pathogens Trypanosoma brucei, Trypanosoma congolense and Leishmania mexicana. The extracts were also tested against Crithidia fasciculata a close relative of Crithidia mellificae, a parasite of bees. Crithidia, Trypanosoma and Leishmania are all members of the order Kinetoplastida. High levels of activity were obtained for all the samples with the levels of activity varying across the sample set. The highest levels of activity were found against L. mexicana. The propolis samples were profiled by using liquid chromatography with high resolution mass spectrometry (LC-MS) and principal components analysis (PCA) of the data obtained indicated there was a wide variation in the composition of the propolis samples. Orthogonal partial least squares (OPLS) associated a butyrate ester of pinobanksin with high activity against T. brucei whereas in the case of T. congolense high activity was associated with methyl ethers of chrysin and pinobanksin. In the case of C. fasciculata highest activity was associated with methyl ethers of galangin and pinobanksin. OPLS modelling of the activities against L. mexicana using the mass spectrometry produced a less successful model suggesting a wider range of active components

    Photobactericidal activity activated by thiolated gold nanoclusters at low flux levels of white light

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    The emergence of antibiotic resistant bacteria is a major threat to the practice of modern medicine. Photobactericidal agents have obtained significant attention as promising candidates to kill bacteria, and they have been extensively studied. However, to obtain photobactericidal activity, an intense white light source or UV-activation is usually required. Here we report a photobactericidal polymer containing crystal violet (CV) and thiolated gold nanocluster ([Au25(Cys)18]) activated at a low flux levels of white light. It was shown that the polymer encapsulated with CV do not have photobactericidal activity under white light illumination of an average 312 lux. However, encapsulation of [Au25(Cys)18] and CV into the polymer activates potent photobactericidal activity. The study of the photobactericidal mechanism shows that additional encapsulation of [Au25(Cys)18] into the CV treated polymer promotes redox reactions through generation of alternative electron transfer pathways, while it reduces photochemical reaction type-ІІ pathways resulting in promotion of hydrogen peroxide (H2O2) production

    Activity of Compounds from Temperate Propolis against Trypanosoma brucei and Leishmania mexicana

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    Ethanolic extracts of samples of temperate zone propolis, four from the UK and one from Poland, were tested against three strains and displayed EC values < 20 µg/mL. The extracts were fractionated, from which 12 compounds and one two-component mixture were isolated, and characterized by NMR and high-resolution mass spectrometry, as 3-acetoxypinobanksin, tectochrysin, kaempferol, pinocembrin, 4'-methoxykaempferol, galangin, chrysin, apigenin, pinostrobin, cinnamic acid, coumaric acid, cinnamyl ester/coumaric acid benzyl ester (mixture), 4',7-dimethoxykaempferol, and naringenin 4',7-dimethyl ether. The isolated compounds were tested against drug-sensitive and drug-resistant strains of and , with the highest activities ≤ 15 µM. The most active compounds against were naringenin 4',7 dimethyl ether and 4'methoxy kaempferol with activity of 15-20 µM against the three strains. The most active compounds against were 4',7-dimethoxykaempferol and the coumaric acid ester mixture, with EC values of 12.9 ± 3.7 µM and 13.1 ± 1.0 µM. No loss of activity was found with the diamidine- and arsenical-resistant or phenanthridine-resistant strains, or the miltefosine-resistant strain; no clear structure activity relationship was observed for the isolated compounds. Temperate propolis yields multiple compounds with anti-kinetoplastid activity

    The Ability to Generate Senescent Progeny as a Mechanism Underlying Breast Cancer Cell Heterogeneity

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    Background Breast cancer is a remarkably heterogeneous disease. Luminal, basal-like, "normal-like", and ERBB2+ subgroups were identified and were shown to have different prognoses. The mechanisms underlying this heterogeneity are poorly understood. In our study, we explored the role of cellular differentiation and senescence as a potential cause of heterogeneity. Methodology/Principal Findings A panel of breast cancer cell lines, isogenic clones, and breast tumors were used. Based on their ability to generate senescent progeny under low-density clonogenic conditions, we classified breast cancer cell lines as senescent cell progenitor (SCP) and immortal cell progenitor (ICP) subtypes. All SCP cell lines expressed estrogen receptor (ER). Loss of ER expression combined with the accumulation of p21Cip1 correlated with senescence in these cell lines. p21Cip1 knockdown, estrogen-mediated ER activation or ectopic ER overexpression protected cells against senescence. In contrast, tamoxifen triggered a robust senescence response. As ER expression has been linked to luminal differentiation, we compared the differentiation status of SCP and ICP cell lines using stem/progenitor, luminal, and myoepithelial markers. The SCP cells produced CD24+ or ER+ luminal-like and ASMA+ myoepithelial-like progeny, in addition to CD44+ stem/progenitor-like cells. In contrast, ICP cell lines acted as differentiation-defective stem/progenitor cells. Some ICP cell lines generated only CD44+/CD24-/ER-/ASMA- progenitor/stem-like cells, and others also produced CD24+/ER- luminal-like, but not ASMA+ myoepithelial-like cells. Furthermore, gene expression profiles clustered SCP cell lines with luminal A and "normal-like" tumors, and ICP cell lines with luminal B and basal-like tumors. The ICP cells displayed higher tumorigenicity in immunodeficient mice. Conclusions/Significance Luminal A and "normal-like" breast cancer cell lines were able to generate luminal-like and myoepithelial-like progeny undergoing senescence arrest. In contrast, luminal B/basal-like cell lines acted as stem/progenitor cells with defective differentiation capacities. Our findings suggest that the malignancy of breast tumors is directly correlated with stem/progenitor phenotypes and poor differentiation potential. © 2010 Mumcuoglu et al

    Multidimensional Signals and Analytic Flexibility: Estimating Degrees of Freedom in Human-Speech Analyses

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    Recent empirical studies have highlighted the large degree of analytic flexibility in data analysis that can lead to substantially different conclusions based on the same data set. Thus, researchers have expressed their concerns that these researcher degrees of freedom might facilitate bias and can lead to claims that do not stand the test of time. Even greater flexibility is to be expected in fields in which the primary data lend themselves to a variety of possible operationalizations. The multidimensional, temporally extended nature of speech constitutes an ideal testing ground for assessing the variability in analytic approaches, which derives not only from aspects of statistical modeling but also from decisions regarding the quantification of the measured behavior. In this study, we gave the same speech-production data set to 46 teams of researchers and asked them to answer the same research question, resulting in substantial variability in reported effect sizes and their interpretation. Using Bayesian meta-analytic tools, we further found little to no evidence that the observed variability can be explained by analysts’ prior beliefs, expertise, or the perceived quality of their analyses. In light of this idiosyncratic variability, we recommend that researchers more transparently share details of their analysis, strengthen the link between theoretical construct and quantitative system, and calibrate their (un)certainty in their conclusions

    SARS-CoV-2 susceptibility and COVID-19 disease severity are associated with genetic variants affecting gene expression in a variety of tissues

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    Variability in SARS-CoV-2 susceptibility and COVID-19 disease severity between individuals is partly due to genetic factors. Here, we identify 4 genomic loci with suggestive associations for SARS-CoV-2 susceptibility and 19 for COVID-19 disease severity. Four of these 23 loci likely have an ethnicity-specific component. Genome-wide association study (GWAS) signals in 11 loci colocalize with expression quantitative trait loci (eQTLs) associated with the expression of 20 genes in 62 tissues/cell types (range: 1:43 tissues/gene), including lung, brain, heart, muscle, and skin as well as the digestive system and immune system. We perform genetic fine mapping to compute 99% credible SNP sets, which identify 10 GWAS loci that have eight or fewer SNPs in the credible set, including three loci with one single likely causal SNP. Our study suggests that the diverse symptoms and disease severity of COVID-19 observed between individuals is associated with variants across the genome, affecting gene expression levels in a wide variety of tissue types
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