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JF Seymour CG Begley U Dirksen JJ Presneill NA Nicola PE Moore OD Schoch P van Asperen B Roth S Burdach AR Dunn 《Canadian Metallurgical Quarterly》1998,92(8):2657-2667
The pathogenesis of acquired pulmonary alveolar proteinosis (PAP), a rare lung disease characterized by excessive surfactant accumulation within the alveolar space, remains obscure. Gene-targeted mice lacking the hematopoietic growth factor granulocyte-macrophage colony-stimulating factor (GM-CSF) or the signal-transducing beta-common chain of the GM-CSF receptor have impaired surfactant clearance and pulmonary pathology resembling human PAP. We therefore investigated the hematopoietic effects of GM-CSF in patients with PAP. The hematologic response of 5 infants with congenital PAP to 5 microgram/kg/d was of normal magnitude. By contrast, despite normal expression of GM-CSF receptor alpha- and beta-common chains on peripheral blood myelomonocytic cells (n = 6) and normal binding affinity of bone marrow mononuclear cells for GM-CSF (n = 3), each of the 12 patients with acquired PAP treated displayed impaired responses to GM-CSF; 5 microgram/kg/d produced only minor eosinophilia, and doses of 7.5 to 20 microgram/kg were required to induce >/=1.5-fold neutrophil increments in the 3 patients who underwent dose-escalation. However, neutrophilic responses to 5 microgram/kg granulocyte colony-stimulating factor (G-CSF) were normal (n = 4). In vitro, the proportion of hematopoietic progenitors responsive to GM-CSF (16.1% +/- 8.9%; P = .042) or interleukin-3 (IL-3; 19.3% +/- 7.7%; P = .063), both of which utilize the beta-common chain of the GM-CSF receptor complex, were reduced among patients with acquired PAP (n = 4) compared with normal bone marrow donor controls (47.2% +/- 25.9% and 40.9% +/- 18.6%, respectively). In the one individual who had complete resolution of lung disease during the period of study, this was temporally associated with correction of this defective in vitro response to GM-CSF and IL-3 on serial assessment. These data establish that patients with acquired PAP have an associated impaired responsiveness to GM-CSF that is potentially pathogenic in the development of their lung disease. Based on these observations, we propose a model of the pathogenesis of acquired PAP that suggests the disease arises as a consequence of an acquired clonal disorder within the hematopoietic progenitor cell compartment. 相似文献
203.
Nitrogen (N) is the most limiting nutrient in crop production. Legumes such as red clover can provide N through biofixation, but securing nitrogen in soil for subsequent crop production must also be considered. Variety selection and management in red clover cropping can influence soil mineral nitrogen (SMN) availability. A field trial to investigate this was conducted with six varieties, under one and two cut management, over 2 years. Dry matter (DM) and N yield, Sclerotinia resistance and SMN availability were assessed. Low DM and N yields (1.6–2.4 t DM ha?1 and 54–83 kg N ha?1) in the first year of cultivation allowed ~?40 kg N ha?1 to become available, but high DM and N yields (10.2–14.6 t DM ha?1 and 405–544 kg N ha?1) allowed ~?20 kg N ha?1 to become available. Wetter weather in 2015 caused significantly more SMN losses than 2016 (20 kg N ha?1 in 2015 and 5 kg N ha?1 in 2016). The varieties Amos, Maro and Milvus lost significantly more SMN in the winter period, which may have been caused by more severe infection of Sclerotinia (these varieties were 50–80% more severely infected other varieties). Varietal effect was non-significant for winter losses in 2016, where no significant varietal differences in Sclerotinia infection were observed. 1 cut made ~?41 kg N ha?1 available in the growing season of 2015, whilst 2 cut made significantly less (37 kg N ha?1). Cutting was non-significant in 2016 but 1 cut was less susceptible to losses in the winter period. Cutting in 2015 did not significantly affect herbage DM and N yields in the first or second cut of 2016. 相似文献
204.
Efficient Decomposition Techniques for Symbolic Analysis of Large-Scale Analog Circuits by State Variable Method 总被引:1,自引:0,他引:1
New tearing techniques for the systematic formulation of the state equations in symbolic normal-form for linear and nonlinear time-invariant large-scale analog circuits are developed. Some examples are given to illustrate the decomposition procedure and the assignment of the connection sources. The partial symbolic state equations of the opamp A 741 are obtained using the tearing approach, while these equations cannot be written working on the whole circuit. 相似文献
205.
Modular and Versatile Spatial Functionalization of Tissue Engineering Scaffolds through Fiber‐Initiated Controlled Radical Polymerization 下载免费PDF全文
Rachael H. Harrison Joseph A. M. Steele Robert Chapman Adam J. Gormley Lesley W. Chow Muzamir M. Mahat Lucia Podhorska Robert G. Palgrave David J. Payne Shehan P. Hettiaratchy Iain E. Dunlop Molly M. Stevens 《Advanced functional materials》2015,25(36):5748-5757
Native tissues are typically heterogeneous and hierarchically organized, and generating scaffolds that can mimic these properties is critical for tissue engineering applications. By uniquely combining controlled radical polymerization (CRP), end‐functionalization of polymers, and advanced electrospinning techniques, a modular and versatile approach is introduced to generate scaffolds with spatially organized functionality. Poly‐ε‐caprolactone is end functionalized with either a polymerization‐initiating group or a cell‐binding peptide motif cyclic Arg‐Gly‐Asp‐Ser (cRGDS), and are each sequentially electrospun to produce zonally discrete bilayers within a continuous fiber scaffold. The polymerization‐initiating group is then used to graft an antifouling polymer bottlebrush based on poly(ethylene glycol) from the fiber surface using CRP exclusively within one bilayer of the scaffold. The ability to include additional multifunctionality during CRP is showcased by integrating a biotinylated monomer unit into the polymerization step allowing postmodification of the scaffold with streptavidin‐coupled moieties. These combined processing techniques result in an effective bilayered and dual‐functionality scaffold with a cell‐adhesive surface and an opposing antifouling non‐cell‐adhesive surface in zonally specific regions across the thickness of the scaffold, demonstrated through fluorescent labelling and cell adhesion studies. This modular and versatile approach combines strategies to produce scaffolds with tailorable properties for many applications in tissue engineering and regenerative medicine. 相似文献
206.
Thomas Reitmaier Nicola J. Bidwell Gary Marsden 《International journal of human-computer studies》2011,69(10):658-668
We reflect on the methods, activities and perspectives we used to situate digital storytelling in two rural African communities in South Africa and Kenya. We demonstrate how in-depth ethnography in a village in the Eastern Cape of South Africa and a design workshop involving participants from that village allowed us to design a prototype mobile digital storytelling system suited to the needs of rural, oral users. By leveraging our prototype as a probe and observing villagers using it in two villages in South Africa and Kenya, we uncovered implications for situating digital storytelling within those communities. Finally, we distil observations relevant to localizing storytelling and their implications for transferring design into a different community. 相似文献
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Vincenzo De Leo Anna Maria Maurelli Chiara Ingrosso Fabio Lupone Lucia Catucci 《International journal of molecular sciences》2021,22(21)
Mussel-inspired chemistry was usefully exploited here with the aim of developing a high-efficiency, environmentally friendly material for water remediation. A micro-structured material based on polydopamine (PDA) was obtained by using liposomes as templating agents and was used for the first time as an adsorbent material for the removal of methylene blue (MB) dye from aqueous solutions. Phospholipid liposomes were made by extrusion and coated with PDA by self-polymerization of dopamine under simple and mild conditions. The obtained Liposome@PDA microspheres were characterized by DLS and Zeta potential analysis, TEM microscopy, and FTIR spectroscopy. The effects of pH, temperature, MB concentration, amount of Liposome@PDA, and contact time on the adsorption process were investigated. Results showed that the highest adsorption capacity was obtained in weakly alkaline conditions (pH = 8.0) and that it could reach up to 395.4 mg g−1 at 298 K. In addition, adsorption kinetics showed that the adsorption behavior fits a pseudo-second-order kinetic model well. The equilibrium adsorption data, instead, were well described by Langmuir isotherm. Thermodynamic analysis demonstrated that the adsorption process was endothermic and spontaneous (ΔG0 = −12.55 kJ mol−1, ΔH0 = 13.37 kJ mol−1) in the investigated experimental conditions. Finally, the applicability of Liposome@PDA microspheres to model wastewater and the excellent reusability after regeneration by removing MB were demonstrated. 相似文献