2,170 research outputs found

    The influence of chemical transport via vapour phase on the properties of chloride and caesium doped V-Fe mixed oxide catalysts in the oxidation of butadiene to furan

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    Chloride and caesium doped V-Fe mixed oxides prepared by different methods and calcined under vapour-phase transport-restricted conditions showed a high initial furan yield of up to 40 mol-% in the oxidation of butadiene. However,after only a few hours on stream a significant loss of activity and selectivity was observed. The reason for this undesirable property was investigated using different bulk and surface-sensitive characterisation methods such as x-ray diffraction, x-ray photoelectron spectroscopy, ransmission electron microscopy and chemical methods. The data obtained for the structure, morphology, and composition of the fresh and used catalysts were correlated with their activity and selectivity properties. The presence of chloride ions was found to be surprisingly necessary for the origin of furan selectivity even up to 50 %, which was however stable only for a short period of time. Chemical transport via chlorides or bromides was observed to be essential for the formation as well as the maintenance of the activity and selectivity properties of the system. The results obtained are interpreted with an assumption that the formation of volatile halides is necessary to form disperse VOx species, which act as active and selective centres for the present reaction. Models for the formation and deactivation of these centres are discussed in this work. In addition, the possible roles of caesium and iron oxides in the catalytic system are also described and disputed

    TGF-beta 1 induces human alveolar epithelial to mesenchymal cell transition (EMT)

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    Background: Fibroblastic foci are characteristic features in lung parenchyma of patients with idiopathic pulmonary fibrosis (IPF). They comprise aggregates of mesenchymal cells which underlie sites of unresolved epithelial injury and are associated with progression of fibrosis. However, the cellular origins of these mesenchymal phenotypes remain unclear. We examined whether the potent fibrogenic cytokine TGF-β1 could induce epithelial mesenchymal transition (EMT) in the human alveolar epithelial cell line, A549, and investigated the signaling pathway of TGF-β1-mediated EMT. Methods: A549 cells were examined for evidence of EMT after treatment with TGF-β1. EMT was assessed by: morphology under phase-contrast microscopy; Western analysis of cell lysates for expression of mesenchymal phenotypic markers including fibronectin EDA (Fn-EDA), and expression of epithelial phenotypic markers including E-cadherin (E-cad). Markers of fibrogenesis, including collagens and connective tissue growth factor (CTGF) were also evaluated by measuring mRNA level using RT-PCR, and protein by immunofluorescence or Western blotting. Signaling pathways for EMT were characterized by Western analysis of cell lysates using monoclonal antibodies to detect phosphorylated Erk1/2 and Smad2 after TGF-β1 treatment in the presence or absence of MEK inhibitors. The role of Smad2 in TGF-β1-mediated EMT was investigated using siRNA. Results: The data showed that TGF-β1, but not TNF-α or IL-1β, induced A549 cells with an alveolar epithelial type II cell phenotype to undergo EMT in a time-and concentration-dependent manner. The process of EMT was accompanied by morphological alteration and expression of the fibroblast phenotypic markers Fn-EDA and vimentin, concomitant with a downregulation of the epithelial phenotype marker E-cad. Furthermore, cells that had undergone EMT showed enhanced expression of markers of fibrogenesis including collagens type I and III and CTGF. MMP-2 expression was also evidenced. TGF-β1-induced EMT occurred through phosphorylation of Smad2 and was inhibited by Smad2 gene silencing; MEK inhibitors failed to attenuate either EMT-associated Smad2 phosphorylation or the observed phenotypic changes. Conclusion: Our study shows that TGF-β1 induces A549 alveolar epithelial cells to undergo EMT via Smad2 activation. Our data support the concept of EMT in lung epithelial cells, and suggest the need for further studies to investigate the phenomenon

    Functional Enhancement of Electrofusion-derived BRIN-BD11 Insulin-secreting Cells After Implantation into Diabetic Mice

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    Electrofusion-derived BRIN-BD11 cells are glucosesensitive insulin-secreting cells which provide an archetypal bioengineered surrogate β-cell for insulin replacement therapy in diabetes mellitus, 5x106 BRIN-BD11 cells were implanted intraperitoneally into severely hyperglycaemic (>24mmol/l) streptozotocin-induced insulin-treated diabetic athymic nude (nu/nu) mice. The implants reduced hyperglycaemia such that insulin injections were discontinued by 5–16 days (<17mmol/l) and normoglycaemia (<9mmol/l) was achieved by 7–20 days. Implanted cells were removed after 28 days and re-established in culture. After re-culture for 20 days, glucose-stimulated (16.7mmol/l) insulin release was enhanced by 121% (p<0.001) compared to non-implanted cells. Insulin responses to glucagon-like peptide-1 (10−9mol/l), cholecystokinin-8 (10−8 mol/l) and L-alanine (10 mmol/l) were increased by 32%, 31% and 68% respectively (p<0.05–0.01). Insulin content of the cells was 148% greater at 20 days after re-culture than before implantation (p<0.001), but basal insulin release (at 5.6 mmol/l glucose) was not changed. After re-culture for 40 days, insulin content declined to 68% of the content before implantation (p<0.01), although basal insulin release was unchanged. However, the insulin secretory responses to glucose, glucagonlike peptide-1, cholecystokinin-8 and L-alanine were decreased after 40 days of re-culture to 65%, 72%, 73% and 42% respectively of the values before implantation (p<0.05–0.01). The functional enhancement of electrofusion-derived surrogate β-cells that were re-cultured for 20 days after implantation and restoration of normoglycaemia indicates that the in vivo environment could greatly assist β-cell engineering approaches to therapy for diabetes

    Current preconception care practice in the Netherlands — An evaluation study among birth care professionals

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    Objective: To evaluate the current practice of preconception care in the Netherlands and the perceptions of birth care professionals concerning preconception care. Methods: We have developed a digital questionnaire and conducted a cross-sectional study by distributing the questionnaire among 102 organisations: 90 primary care midwifery practices and obstetric departments of 12 hospitals in the Southwest region of the Netherlands between December 2020 and March 2021. One birth care professional per organization was asked to complete the questionnaire. Descriptive statistics were used to present the results. Findings: Respondents of eighty-three organisations (81.4 %) filled in the questionnaire, of whom 74 respondents were independent primary care midwives and 9 respondents were obstetricians. Preconception care mostly consisted of an individual consultation in which personalized health and lifestyle advice was given. Among the respondents, 44.4 % reported that the organization had a preconception care protocol. The way in which the consultation was carried out, as well as the health and lifestyle related questions asked, differed between respondents. More than 85 % of the respondents inquire about the following possible risk factors for complications: maternal illnesses, obstetric history, folic acid supplement intake, alcohol intake, smoking, substance abuse, hereditary disease, prescription medication, dietary habits, overweight, and birth defects in the family. The respondents acknowledged that preconception care should be offered to all couples who wish to become pregnant, as opposed to offering preconception care only to those with an increased risk of complications. Still, respondents do not receive many questions regarding the preconception period or requests for preconception care consultations. Key conclusion: Birth care professionals acknowledge the need for preconception care for all couples. In the Netherlands, preconception care consists mostly of an individual consultation with recommendations for health and lifestyle advice. However, the identification of risk factors varies between birth care professionals and less than half of the respondents indicate that they have a protocol available in their practice. Furthermore, the demand of parents-to-be for preconception care is low. More research, that includes more obstetricians, is necessary to investigate if there is a difference between the care provided by primary care midwives and obstetricians. Implications for practice:To increase the awareness and uptake of preconception care, it would be prudent to emphasize its importance to parents-to-be and professionals, and actively promote the use of widespread, standardized protocols for birth care professionals.</p

    Constraining the Two-Higgs-Doublet-Model parameter space

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    We confront the Two-Higgs-Doublet Model with a variety of experimental constraints as well as theoretical consistency conditions. The most constraining data are the \bar B\to X_s\gamma decay rate (at low values of M_{H^\pm}), and \Delta\rho (at both low and high M_{H^\pm}). We also take into account the B\bar B oscillation rate and R_b, or the width \Gamma(Z\to b\bar b) (both of which restrict the model at low values of \tan\beta), and the B^-\to\tau\nu_\tau decay rate, which restricts the model at high \tan\beta and low M_{H^\pm}. Furthermore, the LEP2 non-discovery of a light, neutral Higgs boson is considered, as well as the muon anomalous magnetic moment. Since perturbative unitarity excludes high values of \tan\beta, the model turns out to be very constrained. We outline the remaining allowed regions in the \tan\beta-M_{H^\pm} plane for different values of the masses of the two lightest neutral Higgs bosons, and describe some of their properties.Comment: 17 pages, 17 figure

    Theoretical investigations of a highly mismatched interface: the case of SiC/Si(001)

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    Using first principles, classical potentials, and elasticity theory, we investigated the structure of a semiconductor/semiconductor interface with a high lattice mismatch, SiC/Si(001). Among several tested possible configurations, a heterostructure with (i) a misfit dislocation network pinned at the interface and (ii) reconstructed dislocation cores with a carbon substoichiometry is found to be the most stable one. The importance of the slab approximation in first-principles calculations is discussed and estimated by combining classical potential techniques and elasticity theory. For the most stable configuration, an estimate of the interface energy is given. Finally, the electronic structure is investigated and discussed in relation with the dislocation array structure. Interface states, localized in the heterostructure gap and located on dislocation cores, are identified

    The future of enterprise groupware applications

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    This paper provides a review of groupware technology and products. The purpose of this review is to investigate the appropriateness of current groupware technology as the basis for future enterprise systems and evaluate its role in realising, the currently emerging, Virtual Enterprise model for business organisation. It also identifies in which way current technological phenomena will transform groupware technology and will drive the development of the enterprise systems of the future

    Human Activities and Conservation Awareness between Community Use Zone (CUZ) Areas of Kinabalu Park and Crocker Range Park, Sabah

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    The Parks Enactment 1984 prohibits any human activities in the Park in order to conserve the natural ecosystem but in reality there are some people living inside the Park and doing cultivation. Community Use Zone (CUZ) is a management option in an attempt to strike a balance between the conservation priorities of the Park and the livelihoods of the local communities who depend on the Park for survival. This study looks into the relationship between types of crops planted within the CUZ areas, evaluate the contribution for the local communities’ livelihood, and determine the perception and conservation awareness of local community activities. The data for this study was collected by using face-to-face interview technique. Closed and open-ended structured questions were used in the interview. Apart from that observation was useful to obtained information which cannot achieve from structured interviews. Percentage, mean and range were used to summarize the results. With the use of socioeconomic survey and economic valuation on sales products approach, it was possible to determine the objectives of this study. Major crops grown are permanent crops such as rubber trees, fruit trees, and cash crops such as vegetables, cocoa and coffee trees were identified as the type of crops that were cultivated for economic sources by farmers in Kg. Sayap, Kota Belud and Kg. Mongool Baru Ulu Senagang, Keningau/Tenom. Rubber trees contributed the highest source of income followed by fruit trees such as durian, langsat and rambutan, cocoa trees and vegetables. The study showed that the perception and conservation awareness of the local communities in both villages had high awareness level. They are aware of the issues that concerning forest conservation. The study had determined that the CUZ is a tool management for the local communities to survive their living which is recommended to be applied but further research on the local communities’ livelihood dependency on protected areas should be conducted for the sake of forest conservation
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