727 resultados para HVAC engineering
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PURPOSE: Small intestinal submucosa is a xenogenic, acellular, collagen rich membrane with inherent growth factors that has previously been shown to promote in vivo bladder regeneration. We evaluate in vitro use of small intestinal submucosa to support the individual and combined growth of bladder urothelial cells and smooth muscle cells for potential use in tissue engineering techniques, and in vitro study of the cellular mechanisms involved in bladder regeneration. MATERIALS AND METHODS: Primary cultures of human bladder urothelial cells and smooth muscle cells were established using standard enzymatic digestion or explant techniques. Cultured cells were then seeded on small intestinal submucosa at a density of 1 x 105 cells per cm.2, incubated and harvested at 3, 7, 14 and 28 days. The 5 separate culture methods evaluated were urothelial cells seeded alone on the mucosal surface of small intestinal submucosa, smooth muscle cells seeded alone on the mucosal surface, layered coculture of smooth muscle cells seeded on the mucosal surface followed by urothelial cells 1 hour later, sandwich coculture of smooth muscle cells seeded on the serosal surface followed by seeding of urothelial cells on the mucosal surface 24 hours later, and mixed coculture of urothelial cells and smooth muscle cells mixed and seeded together on the mucosal surface. Following harvesting at the designated time points small intestinal submucosa cell constructs were formalin fixed and processed for routine histology including Masson trichrome staining. Specific cell growth characteristics were studied with particular attention to cell morphology, cell proliferation and layering, cell sorting, presence of a pseudostratified urothelium and matrix penetrance. To aid in the identification of smooth muscle cells and urothelial cells in the coculture groups, immunohistochemical analysis was performed with antibodies to alpha-smooth muscle actin and cytokeratins AE1/AE3. RESULTS: Progressive 3-dimensional growth of urothelial cells and smooth muscle cells occurred in vitro on small intestinal submucosa. When seeded alone urothelial cells and smooth muscle cells grew in several layers with minimal to no matrix penetration. In contrast, layered, mixed and sandwich coculture methods demonstrated significant enhancement of smooth muscle cell penetration of the membrane. The layered and sandwich coculture techniques resulted in organized cell sorting, formation of a well-defined pseudostratified urothelium and multilayered smooth muscle cells with enhanced matrix penetration. With the mixed coculture technique there was no evidence of cell sorting although matrix penetrance by the smooth muscle cells was evident. Immunohistochemical studies demonstrated that urothelial cells and smooth muscle cells maintain the expression of the phenotypic markers of differentiation alpha-smooth muscle actin and cytokeratins AE1/AE3. CONCLUSIONS: Small intestinal submucosa supports the 3-dimensional growth of human bladder cells in vitro. Successful combined growth of bladder cells on small intestinal submucosa with different seeding techniques has important future clinical implications with respect to tissue engineering technology. The results of our study demonstrate that there are important smooth muscle cell-epithelial cell interactions involved in determining the type of in vitro cell growth that occurs on small intestinal submucosa. Small intestinal submucosa is a valuable tool for in vitro study of the cell-cell and cell-matrix interactions that are involved in regeneration and various disease processes of the bladder.
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Synthesis of polyhydroxyalkanoates (PHAs) in crop is viewed as an attractive approach for the production of this family of biodegradable plastics in large quantities and at low costs. Synthesisof PHAs containing various monomers has so far been demonstrated in the cytosol, plastids, and peroxisomes of plants. Several biochemical pathways have been modifies to achieve this, including the isoprenois pathway, the fatty acid biosynthetic pathway, and the fatty acid
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To control the selective adhesion of human endothelial cells and human serum proteins to bioceramics of different compositions, a multifunctional ligand containing a cyclic arginine-glycine-aspartate (RGD) peptide, a tetraethylene glycol spacer, and a gallate moiety was designed, synthesized, and characterized. The binding of this ligand to alumina-based, hydroxyapatite-based, and calcium phosphate-based bioceramics was demonstrated. The conjugation of this ligand to the bioceramics induced a decrease in the nonselective and integrin-selective binding of human serum proteins, whereas the binding and adhesion of human endothelial cells was enhanced, dependent on the particular bioceramics.
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Approximately 65% of Iowa's roads are surfaced with aggregates composed of crushed limestone and/or gravel. Rural Iowan's regard these roads as a very important part of their lives. Therefore, the slide-tape presentation, "Maintaining Granular Surfaced Roads" was developed to aid the motor grader operator to better understand the procedures required t o maintain aggregate surfaced roads. A typical cross-section is presented with the proper nomenclature assigned to the roadway features to facilitate the operator's understanding of the basic terms used the program. The following areas are expanded: safety , dragging, cutting, intersections , superelevations, and reporting any discrepancies. The operator's attention to detail can enhance the economy of the state and contribute to the savings of lives on rural highways.
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Research project HR-234A was sponsored by the Iowa Highway Research Board and the Iowa Department of Transportation. In the preparation of this compilation of highway and street laws of Iowa, an attempt has been made to include those sections of the Iowa Code Annotated and Iowa Digest to which reference is frequently required by the Department of Transportation, counties, cities and towns in their conduct of highway and street administration, construction and maintenance. This publication is offered with the hope and belief that it will prove to be of value and assistance to those concerned with the problems of establishing, maintaining and administering a highway and street program. Because of the broad scope of highway and street work and the many interrelated provisions of Iowa law, and usable size, some Code provision which are insignificant to the principal subject were omitted out of necessity; others were omitted to avoid repetition. A general index is provided at the end of the text of this volume. Each major topic is divided into subtopics and is accompanied by appropriate Code sections. Specific section numbers as they appear in the Code are in.
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Sign vandalism has traditionally been a vexing problem for Iowa counties. The extent of the cost and incidence of these acts have never been fully ascertained, but a 1990 survey indicated that they cost Iowa counties more than 1.5 million dollars annually. In 1990, the Iowa Legislature recognized the seriousness of the problem and strengthened the existing sign vandalism law by increasing the penalty for illegal possession of a traffic control device from a simple to a serious misdemeanor. However, the courts must be willing to prosecute vandals to the magnitude provided in the Iowa Code. An educational campaign begun in 1987 involving over 200 Iowa school districts to educate students on the seriousness of the problem evidently did not have the effect of dramatically reducing the overall cost of sign vandalism in Iowa. This study sought to define the scope of the problem and possibly offer some effective countermeasures to combat sign vandalism and theft in Iowa.
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In this paper we explore the possibility of improving, by genetic engineering, the resistance of insulin-secreting cells to the metabolic and inflammatory stresses that are anticipated to limit their function and survival when encapsulated and transplanted in a type 1 diabetic environment. We show that transfer of the Bcl-2 antiapoptotic gene, and of genes specifically interfering with cytokine intracellular signaling pathways, greatly improves resistance of the cells to metabolic limitations and inflammatory stresses.
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The generation of a high productivity cell line is a critical step in the production of a therapeutic protein. Many innovative engineering strategies have been devised in order to maximize the expression rate of production cells for increased process efficiency. Less effort has focused on improvements to the cell line generation process, which is typically long and laborious when using mammalian cells. Based on unexpected findings when generating stable CHO cell lines expressing human IL-17F, we studied the benefit of expressing this protein during the establishment of production cell lines. We demonstrate that IL-17F expression enhances the rate of selection and overall number of selected cell lines as well as their transgene expression levels. We also show that this benefit is observed with different parental CHO cell lines and selection systems. Furthermore, IL-17F expression improves the efficiency of cell line subcloning processes. IL-17F can therefore be exploited in a standard manufacturing process to obtain higher productivity clones in a reduced time frame.
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Recognition by the T-cell receptor (TCR) of immunogenic peptides (p) presented by class I major histocompatibility complexes (MHC) is the key event in the immune response against virus infected cells or tumor cells. The major determinant of T cell activation is the affinity of the TCR for the peptide-MHC complex, though kinetic parameters are also important. A study of the 2C TCR/SIYR/H-2Kb system using a binding free energy decomposition (BFED) based on the MM-GBSA approach had been performed to assess the performance of the approach on this system. The results showed that the TCR-p-MHC BFED including entropic terms provides a detailed and reliable description of the energetics of the interaction (Zoete and Michielin, 2007). Based on these results, we have developed a new approach to design sequence modifications for a TCR recognizing the human leukocyte antigen (HLA)-A2 restricted tumor epitope NY-ESO-1. NY-ESO-1 is a cancer testis antigen expressed not only in melanoma, but also on several other types of cancers. It has been observed at high frequencies in melanoma patients with unusually positive clinical outcome and, therefore, represents an interesting target for adoptive transfer with modified TCR. Sequence modifications of TCR potentially increasing the affinity for this epitope have been proposed and tested in vitro. T cells expressing some of the proposed TCR mutants showed better T cell functionality, with improved killing of peptide-loaded T2 cells and better proliferative capacity compared to the wild type TCR expressing cells. These results open the door of rational TCR design for adoptive transfer cancer therapy.
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The Institute for Transportation (InTrans) at Iowa State University (ISU) developed an internship mentoring program in collaboration with the Iowa Department of Transportation (DOT) to provide additional mentorship to both student interns and Iowa DOT intern managers. For the summer 2013 Iowa DOT Engineering Intern Development and Management Program, this report summarizes the following: * Mentoring activities conducted by ISU; * Results of the different intern program success assessments that were conducted; * Experiences, lessons learned, and recommendations; * Program benefits that were realized.
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Scopolamine is an alkaloid widely used in medicine for its anticholinergic activity. The aim of this review is to show that metabolic engineering techniques constitute a suitable tool to improve the production of tropane alkaloids, focusing in particular on scopolamine. We present an overview of results obtained by various research groups, including our own, who have studied the overexpression of genes involved in the biosynthesis of scopolamine in different plant species that produce tropane alkaloids. Experiments carried out to improve production in hairy root cultures will also be described, as well as those attempting to biotransform hyoscyamine into scopolamine in roots and transgenic tobacco cells.
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Multiplan spreadsheet solutions were developed for a set of hydraulic and highway engineering computations of common interest to county engineers. These include earthwork, vertical and horizontal curves, staking superelevated curves and sign inventories for highways. The hydraulic applications were ditch flow, runoff, culvert size and stage discharge.
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The objective of phase one of this research was to assess the degree to which currently employed Iowa Department of Transportation (DOT) employees would be affected by a more aggressive policy to recruit and retain women and minority engineers. The DOT's "Future Agenda" was used as a baseline to focus on efforts to update and implement a recruitment plan that would target underrepresented classes. The primary question that emerged out of phase one was how could the Iowa DOT strengthen its ties with Iowa State University (ISU) to produce increased numbers of in-state applicants for engineering positions. This introduced the objective of phase two, which was to identify problem areas resulting in unacceptably high attrition rates for women, minorities, and to a lesser degree, Caucasian men in the College of Engineering at ISU, particularly Civil and Construction Engineering (CCE). Past research has focused on (1) projected shortages of qualified civil engineers, (2) the obstacles confronting women in a traditionally male-oriented profession, and (3) minorities who are often unprepared to succeed in the rigors of an engineering curriculum because of a lack of academic preparedness. The researchers in this study, in contrast, chose to emphasize institutional reasons why women, minorities, and some Caucasian men often feel a sense of isolation in the engineering program. It was found that one of the key obstacles to student retention is the lack of visibility of the civil engineering profession. The visibility problem led to the hypothesis that many engineering students do not have a clear conception of what the practice of civil engineering entails. It was found that this may be a better predictor of attrition than the stereotypical assumption that a majority of students leave their engineering programs because they are not academically able to compete. Recommendations are offered to strengthen the ties between ISU's Department of CCE and the Iowa DOT in order to counter the visibility issue. It was concluded that this is a vital step because over the next 5-15 years 40% of DOT engineers currently employed will be phasing into retirement. If the DOT expects to draw sufficient numbers of engineers from within the state of Iowa and if increasing numbers of them are to be women and minorities, a university connection will help to produce the qualified applicants to fulfill this need.
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Excessive speed on State and County highways is recognized as a serious problem by many Iowans. Speed increases both the risk and severity of accidents. Studies conducted by the FHWA and NHTSA have concluded that if average speeds were increased by five MPH, fatalities would increase by at least 2,200 annually. Along with the safety problems associated with excessive speed are important energy considerations. When the national speed limit was lowered to 55 MPH in 1974, a tremendous savings in fuel was realized. The estimated actual savings for automobiles amounted to 2.2 billion gallons, an average of 20.75 gallons for each of the 106 million automobiles registered in 1975. These benefits prompted the Federal-Aid Amendment of 1974 requiring annual State enforcement certification as a prerequisite for approval of Federal-aid highway projects. In 1978, the United States D.O.T. recommended to Congress significant changes in speed limit legislation designed to increase compliance with the national speed limit. The Highway Safety Act of 1978 provides for both withholding Federal-aid highway funds and awarding incentive grants based on speed compliance data submitted annually. The objective of this study was to develop and make operational, an automatic speed monitoring system which would have flexible capabilities of collecting accurate speed data on all road systems in Iowa. It was concluded that the Automatic Speed Monitoring Program in Iowa has been successful and needed data is being collected in the most economical manner possible.