971 resultados para Crystal engineering


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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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Except for the first 2 years since July 29, 1968, Arenal volcano has continuously erupted compositionally monotonous and phenocryst-rich (similar to35%) basaltic andesites composed of plagioclase (plag), orthopyroxene (opx), clinopyroxene (cpx), spinel olivine. Detailed textural and compositional analyses of phenocrysts, mineral inclusions, and microlites reveal comparable complexities in any given sample and identify mineral components that require a minimum of four crystallization environments. We suggest three distinct crystallization environments crystallized low Mg# (<78) silicate phases from andesitic magma but at different physical conditions, such as variable pressure of crystallization and water conditions. The dominant environment, i.e., the one which accounts for the majority of minerals and overprinted all other assemblages near rims of phenocrysts, cocrystallized clinopyroxene (Mg# similar to71-78), orthopyroxene (Mg# similar to71-78), titanomagnetite and plagioclase (An(60) to An(85)). The second environment cocrystallized clinopyroxene (Mg# 71-78), olivine (<Fo(78)), titanomagnetite, and very high An (similar to90) plagioclase, while the third cocrystallized clinopyroxene (Mg# 71-78) with high (>7) Al/Ti and high (>4 wt.%) Al2O3, titanomagnetite with considerable Al2O3 (10-18 wt.%) and possibly olivine but appears to lack plagioclase. A fourth crystallization environment is characterized by clinopyroxene (e.g., Mg#=similar to78-85; Cr2O3=0.15-0.7 wt.%), Al-, Cr-rich spinel olivine (similar toFo(80)), and in some circumstances high-An (>80) plagioclase. This assemblage seems to record mafic inputs into the Arenal system and crystallization at high to low pressures. Single crystals cannot be completely classified as xenocrysts, antecrysts (cognate crystals), or phenocrysts, because they often contain different parts each representing a different crystallization environment and thus belong to different categories. Bulk compositions are mostly too mafic to have crystallized the bulk of ferromagnesian minerals and thus likely do not represent liquid compositions. On the other hand, they are the cumulative products of multiple mixing events assembling melts and minerals from a variety of sources. The driving force for this multistage mixing evolution to generate erupting basaltic andesites is thought to be the ascent of mafic magma from lower crustal levels to subvolcanic depths which at the same time may also go through compositional modification by fractionation and assimilation of country rocks. Thus, mafic magmas become basaltic andesite through mixing, fractionation and assimilation by the time they arrive at subvolcanic depths. We infer new increments of basaltic andesite are supplied nearly continuously to the subvolcanic reservoir concurrently to the current eruption and that these new increments are blended into the residing, subvolcanic magma. Thus, the compositional monotony is mostly the product of repetitious production of very similar basaltic andesite. Furthermore, we propose that this quasi-constant supply of small increments of magma is the fundamental cause for small-scale, decade-long continuous volcanic activity; that is, the current eruption of Arenal is flux-controlled by inputs of mantle magmas. (C) 2004 Elsevier B.V. All rights reserved.

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OBJECTIVE: Monosodium urate monohydrate (MSU) crystal-induced interleukin-1β (IL-1β) secretion is a critical factor in the pathogenesis of gout. However, without costimulation by a proIL-1β-inducing factor, MSU crystals alone are insufficient to induce IL-1β secretion. The responsible costimulatory factors that act as a priming endogenous signal in vivo are not yet known. We undertook this study to analyze the costimulatory properties of myeloid-related protein 8 (MRP-8) and MRP-14 (endogenous Toll-like receptor 4 [TLR-4] agonists) in MSU crystal-induced IL-1β secretion and their relevance in gout. METHODS: MRP-8/MRP-14 was measured in paired serum and synovial fluid samples by enzyme-linked immunosorbent assay (ELISA) and localized in synovial tissue from gout patients by immunohistochemistry. Serum levels were correlated with disease activity, and MSU crystal-induced release of MRPs from human phagocytes was measured. Costimulatory effects of MRP-8 and MRP-14 on MSU crystal-induced IL-1β secretion from phagocytes were analyzed in vitro by ELISA, Western blotting, and polymerase chain reaction. The impact of MRP was tested in vivo in a murine MSU crystal-induced peritonitis model. RESULTS: MRP-8/MRP-14 levels were elevated in the synovium, tophi, and serum of patients with gout and correlated with disease activity. MRP-8/MRP-14 was released by MSU crystal-activated phagocytes and increased MSU crystal-induced IL-1β secretion in a TLR-4-dependent manner. Targeted deletion of MRP-14 in mice led to a moderately reduced response of MSU crystal-induced inflammation in vivo. CONCLUSION: MRP-8 and MRP-14, which are highly expressed in gout, are enhancers of MSU crystal-induced IL-1β secretion in vitro and in vivo. These endogenous TLR-4 ligands released by activated phagocytes contribute to the maintenance of inflammation in gout.

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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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Many researchers have concluded that secondary or delayed ettringite is responsible for serious premature deterioration of concrete highways. In some poorly performing Iowa concretes, ettringite is the most common secondary mineral but its role in premature deterioration is uncertain since some researchers still maintain that secondary ettringite does not itself cause deterioration. The current research project was designed to determine experimentally if it is possible to reduce secondary ettringite formation in concrete by treating the concrete with commercial crystallization inhibitor chemicals. The hypothesis is such that if the amount of ettringite is reduced, there will also be a concomitant reduction of concrete expansion and cracking. If both ettringite formation and deterioration are simultaneously reduced, then the case for ettringite induced expansion/cracking is strengthened. The experiment used four commercial inhibitors - two phosphonates, a polyacrylic acid, and a phosphate ester. Concrete blocks were subjected to continuous immersion, wet/dry and freeze/thaw cycling in sodium sulfate solutions and in sulfate solutions containing an inhibitor. The two phosphonate inhibitors, Dequest 2060 and Dequest 2010, manufactured by Monsanto Co., were effective in reducing ettringite nucleation and growth in concrete. Two other inhibitors, Good-rite K752 and Wayhib S were somewhat effective, but less so than the two phosphonates. Rapid experiments with solution growth inhibition of ettringite without the presence of concrete phases were used to explore the mechanisms of inhibition of this mineral. Reduction of new ettringite formation in concrete blocks also reduced expansion and cracking of the blocks. This relationship clearly links concrete expansion with this mineral - a conclusion that some research workers have disputed despite theoretical arguments for such a relationship and despite numerous observations of ettringite mineralization in prematurely deteriorated concrete highways. Secondary ettringite nucleation and growth must cause concrete expansion because the only known effect of the inhibitor chemicals is to reduce crystal nucleation and growth, and the inhibitors cannot in any other way be responsible for the reduction in expansion. The mechanism of operation of the inhibitors on ettringite reduction is not entirely clear but the solution growth experiments show that they prevent crystallization of a soluble ettringite precursor gel. The present study shows that ettringite growth alone is not responsible for expansion cracking because the experiments showed that most expansion occurs under wet/dry cycling, less under freeze/thaw cycling, and least under continuous soaking conditions. It was concluded from the different amounts of damage that water absorption by newly-formed, minute ettringite crystals is responsible for part of the observed expansion under wet/dry conditions, and that reduction of freeze resistance by ettringite filling of air-entrainment voids is also important in freeze/thaw environments.

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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.