1,363 research outputs found
Effect of organic and inorganic fertilizers on yield and mineral content of onion (Allium cepa L.)
This experiment was conducted to find the influence of both organic and mineral fertilizer on the quality and yield of onion (Allium cepa L.) and also on the macro and micro element contents of onion bulb. Cattle manure was applied at 0, 20, 40 and 60 t/ha. Nitrogen:phosphorus:potassium was applied at the recommended dose of 120:100:150 with half of the recommended rate of NPK. Yield, yield components and macro-micro element contents were measured. In the first year, bulb width and number of storage leaf were influenced significantly by the treatments. In the second year, applications affected onion yield significantly but bulb number, fleshy thickness, bulb weight, bulb height, number of storage leaf, number of shoot tip and number of dried leaves were not influenced statistically. In the first year, treatments influenced K content, but did not influence N, P, Ca, Na, Mg, Fe, Zn, Cu and Mn contents of the onion bulb. In the second year, the treatments influenced Na content, but did not influence the others.Key words: Onion, organic fertilizer, mineral fertilizer, yield, macro elements, micro elements
Glycosaminoglycan mimetric peptide nanofibers promote mineralization by osteogenic cells
Cataloged from PDF version of article.Bone tissue regeneration is accomplished by concerted regulation of protein-based extracellular matrix components, glycosaminoglycans (GAGs) and inductive growth factors. GAGs constitute a significant portion of the extracellular matrix and have a significant impact on regulating cellular behavior, either directly or through encapsulation and presentation of growth factors to the cells. In this study we utilized a supramolecular peptide nanofiber system that can emulate both the nanofibrous architecture of collagenous extracellular matrix and the major chemical composition found on GAGs. GAGs and collagen mimetic peptide nanofibers were designed and synthesized with sulfonate and carboxylate groups on the peptide scaffold. The GAG mimetic peptide nanofibers interact with bone morphogenetic protein-2 (BMP-2), which is a critical growth factor for osteogenic activity. The GAG mimicking ability of the peptide nanofibers and their interaction with BMP-2 promoted osteogenic activity and mineralization by osteoblastic cells. Alkaline phosphatase activity, Alizarin red staining and energy dispersive X-ray analysis spectroscopy indicated the efficacy of the peptide nanofibers in inducing mineralization. The multifunctional and bioactive microenvironment presented here provides osteoblastic cells with osteogenic stimuli similar to those observed in native bone tissue
Energy and thermal performance evaluation of an automated snow and ice removal system at airports using numerical modeling and field measurements
Airports are moving toward utilizing clean energy technologies along with the implementation of practices that reduce local emissions. This includes replacing fossil fuel-based with electricity-based operations. These changes would significantly impact the energy demand profile of airports. Electrically-conductive concrete (ECON) is currently a focus of heated pavement design for replacing conventional snow removal practices. ECON heated pavement systems (HPSs) use electricity to heat the pavement surface. Since experimental studies are resource intensive and ECON HPS performance depends on weather conditions, developing a field data-validated numerical model enables its long term energy performance evaluation. In this research, a finite element (FE) model is developed and experimentally-validated using two proposed model-updating methods for full-scale ECON HPS test slabs constructed at Des Moines International Airport (DSM) in Iowa. The model predicts energy demands and average surface temperatures within 2% and 13% respectively. The estimated power demand ranges from 325 to 460 W/m2 for different weather conditions. The results of this study provide a validated tool that can be used to evaluate the energy demand of ECON HPS. Studying the energy demand of ECON HPS opens the way for developing control strategies to optimize its energy use which will contribute to developing sustainable communities
Bone-Like Mineral Nucleating Peptide Nanofibers Induce Differentiation of Human Mesenchymal Stem Cells into Mature Osteoblasts
Cataloged from PDF version of article.A bone implant should integrate to the tissue through a bone-like mineralized interface, which requires increased osteoblast activity at the implant-tissue boundary. Modification of the implant surface with synthetic bioinstructive cues facilitates on-site differentiation of progenitor stem cells to functional mature osteoblasts and results in subsequent mineralization. Inspired by the bioactive domains of the bone extracellular matrix proteins and the mussel adhesive proteins, we synthesized peptide nanofibers to promote bone-like mineralization on the implant surface. Nanofibers functionalized with osteoinductive collagen I derived Asp-Gly-Glu-Ala (DGEA) peptide sequence provide an advantage in initial adhesion, spreading, and early commitment to osteogenic differentiation for mesenchymal stem cells (hMSCs). In this study, we demonstrated that this early osteogenic commitment, however, does not necessarily guarantee a priority for maturation into functional osteoblasts. Similar to natural biological cascades, early commitment should be further supported with additional signals to provide a long-term effect on differentiation. Here, we showed that peptide nanofibers functionalized with Glu-Glu-Glu (EEE) sequence enhanced mineralization abilities due to osteoinductive properties for late-stage differentiation of hMSCs. Mussel-inspired functionalization not only enables robust immobilization on metal surfaces, but also improves bone-like mineralization under physiologically simulated conditions. The multifunctional osteoinductive peptide nanofiber biointerfaces presented here facilitate osseointegration for long-term clinical stability. © 2014 American Chemical Society
Animal Models for Limbal Stem Cell Deficiency: A Critical Narrative Literature Review
\ua9 2024, The Author(s). This literature review will provide a critical narrative overview of the highlights and potential pitfalls of the reported animal models for limbal stem cell deficiency (LSCD) and will identify the neglected aspects of this research area. There exists significant heterogeneity in the literature regarding the methodology used to create the model and the predefined duration after the insult when the model is supposedly fully fit for evaluations and/or for testing various therapeutic interventions. The literature is also replete with examples wherein the implementation of a specific model varies significantly across different studies. For example, the concentration of the chemical, as well as its duration and technique of exposure in a chemically induced LSCD model, has a great impact not only on the validity of the model but also on the severity of the complications. Furthermore, while some models induce a full-blown clinical picture of total LSCD, some are hindered by their ability to yield only partial LSCD. Another aspect to consider is the nature of the damage induced by a specific method. As thermal methods cause more stromal scarring, they may be better suited for assessing the anti-fibrotic properties of a particular treatment. On the other hand, since chemical burns cause more neovascularisation, they provide the opportunity to tap into the potential treatments for anti-neovascularisation. The animal species (i.e., rats, mice, rabbits, etc.) is also a crucial factor in the validity of the model and its potential for clinical translation, with each animal having its unique set of advantages and disadvantages. This review will also elaborate on other overlooked aspects, such as the anaesthetic(s) used during experiments, the gender of the animals, care after LSCD induction, and model validation. The review will conclude by providing future perspectives and suggestions for further developments in this rather important area of research
Eltrombopag for the treatment of immune thrombocytopenia: The aegean region of Turkey experience
Objective: Immune thrombocytopenia (ITP) is an immune-mediated disease characterized by transient or persistent decrease of the platelet count to less than 100x109/L. Although it is included in a benign disease group, bleeding complications may be mortal. With a better understanding of the pathophysiology of the disease, thrombopoietin receptor agonists, which came into use in recent years, seem to be an effective option in the treatment of resistant cases. This study aimed to retrospectively assess the efficacy, long-term safety, and tolerability of eltrombopag in Turkish patients with chronic ITP in the Aegean region of Turkey. Materials and Methods: Retrospective data of 40 patients with refractory ITP who were treated with eltrombopag in the Aegean region were examined and evaluated. Results: The total rate of response was 87%, and the median duration of response defined as the number of the platelets being over 50x109/L was 19.5 (interquartile range: 5-60) days. In one patient, venous sinus thrombosis was observed with no other additional risk factors due to or related to thrombosis. Another patient with complete response and irregular follow-up for 12 months was lost due to sudden death as the result of probable acute myocardial infarction. Conclusion: Although the responses to eltrombopag were satisfactory, patients need to be monitored closely for overshooting platelet counts as well as thromboembolic events. © 2015 Turkish Society of Hematology. All rights reserved
Surface-adhesive and osteogenic self-assembled peptide nanofibers for bioinspired functionalization of titanium surfaces
Mechanical properties and biological inertness of titanium provide potential in orthopedic and dental implants. However, integration of titanium-based implants into the existing tissue is a major problem. Herein, we demonstrate biofunctionalization of titanium surfaces through a mussel-inspired adhesion mechanism conjugated to self-assembled peptide nanofibers in order to overcome biocompatibility issues. A Dopa conjugated peptide nanofiber coating was used along with bioactive peptide sequences for osteogenic activity to enhance osseointegration of medical grade titanium surface, TiAl6V4 alloy. Dopa-mediated immobilization of osteogenic peptide nanofibers on titanium surfaces created an osteoconductive interface between osteoblast-like cells and inhibited adhesion and viability of soft tissue forming fibroblasts compared to the uncoated titanium substrate. This biofunctionalization strategy can be extended into other surface immobilization systems owing to the versatile adhesive properties of Dopa and the ease of ligand conjugation to peptide amphiphile molecules. © 2012 The Royal Society of Chemistry
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