Activity of glucose oxidase functionalized onto magnetic nanoparticles

BACKGROUND: Magnetic nanoparticles have been significantly used for coupling with biomolecules, due to their unique properties. METHODS: Magnetic nanoparticles were synthesized by thermal co-precipitation of ferric and ferrous chloride using two different base solutions. Glucose oxidase was bound to the particles by direct attachment via carbodiimide activation or by thiophene acetylation of magnetic nanoparticles. Transmission electron microscopy was used to characterize the size and structure of the particles while the binding of glucose oxidase to the particles was confirmed using Fourier transform infrared spectroscopy. RESULTS: The direct binding of glucose oxidase via carbodiimide activity was found to be more effective, resulting in bound enzyme efficiencies between 94–100% while thiophene acetylation was 66–72% efficient. Kinetic and stability studies showed that the enzyme activity was more preserved upon binding onto the nanoparticles when subjected to thermal and various pH conditions. The overall activity of glucose oxidase was improved when bound to magnetic nanoparticles CONCLUSION: Binding of enzyme onto magnetic nanoparticles via carbodiimide activation is a very efficient method for developing bioconjugates for biological application

Uncertainty, Irreversibility, And Investment In Secondgeneration Biofuels

The present study formalizes and quantifies the importance of uncertainty for investment in a corn-stover based cellulosic biofuel plant. Using a real options model we recover prices of gasoline that would trigger entry into the market and calculate the portion of that entry trigger price required to cover cost and the portion that corresponds to risk premium. We then discuss the effect of managerial flexibility on the entry risk premium and the prices of gasoline that would trigger mothballing, reactivation, and exit. Results show that the risk premium required by plants to enter the second-generation biofuel market is likely to be substantial. The analysis also reveals that a break-even approach (which ignores the portion of entry price composed of risk premium), and the traditional Marshallian approach (which ignores the portion of entry price composed of both the risk premium and the drift rate), would significantly underestimate the gasoline entry trigger price and the magnitude of that underestimation increases as both volatility and mean of gasoline prices increase. Results also uncover a great deal of hysteresis (i.e. a range of gasoline prices for which there is neither entry nor exit in the market) in entry/exit behavior by plants. Hysteresis increases as gasoline prices become more volatile. Hysteresis suggests that, at the industry level, positive (negative) demand shocks will have a significant impact on prices (production) and a limited impact on production (prices). In combination all of these results suggest that policies supporting second generation biofuels may have fallen short of their targets because of their failure to alleviate uncertainty

TGF-β Activation and Signaling in Angiogenesis

The transforming growth factor-β (TGF-β) signaling pathway regulates various cellular processes during tissue and organ development and homeostasis. Deregulation of the expression and/or functions of TGF-β ligands, receptors or their intracellular signaling components leads to multiple diseases including vascular pathologies, autoimmune disorders, fibrosis and cancer. In vascular development, physiology and disease TGF-β signaling can have angiogenic and angiostatic properties, depending on expression levels and the tissue context. The objective of this chapter is to analyze the mechanisms that contribute to the activation and signaling of TGF-β in developmental, physiological and pathological angiogenesis, with a particular emphasis on the importance of TGF-β signaling in the mammalian central nervous system (CNS)

Origin of the Mosaicity in Graphene Grown on Cu(111)

We use low-energy electron microscopy to investigate how graphene grows on Cu(111). Graphene islands first nucleate at substrate defects such as step bunches and impurities. A considerable fraction of these islands can be rotationally misaligned with the substrate, generating grain boundaries upon interisland impingement. New rotational boundaries are also generated as graphene grows across substrate step bunches. Thus, rougher substrates lead to higher degrees of mosaicity than do flatter substrates. Increasing the growth temperature improves crystallographic alignment. We demonstrate that graphene growth on Cu(111) is surface diffusion limited by comparing simulations of the time evolution of island shapes with experiments. Islands are dendritic with distinct lobes, but unlike the polycrystalline, four-lobed islands observed on (100)-textured Cu foils, each island can be a single crystal. Thus, epitaxial graphene on smooth, clean Cu(111) has fewer structural defects than it does on Cu(100).Comment: Article revised following reviewer comment

Explorations of computer-based design tools for urban design projects

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1992.Includes bibliographical references (leaves 117-118).This thesis is an investigation into issues involving computers, information, and automation in the designing of large-scale environments. It is an attempt to understand the issues at root in developing an "intelligent" design environment which provides tools for handling tasks often too mundane and distracting for sustained design activity. In the process of devising these tools, fundamental issues regarding the elements or objects of design, their characteristics, and the transformations they undergo are revealed in light of the particular capabilities of the computer. This study was undertaken as an attempt to discover these issues for myself by working to create a system of tools on top of an existing computer-aided design program - a personalized design environment. The path of discovery taken is reconstructed in this paper, in part to illustrate some of the pitfalls of dealing with real-world programming tasks, and also to demonstrate the revelation of the inherent issues that are involved when attempting such a project. Although the programmed end-product is incomplete and greatly simplifies the true nature of such a design problem, the lessons learned are distilled and clarified to provide a basis for further work and investigation in this field. The first part is a synopsis of issues related to computer-aided design: an historic overview, current applications, on-going research and forecasts. This section is provided to illustrate the foundation of understanding that I had when undertaking to develop tools of my own. The second part includes the initial tool concepts and their intended purposes, a discussion of hardware and software platforms, and numerous considerations I was compelled to address while developing modeling and information-handling components of the design environment. Part three deals in depth with a sophisticated tool proposal for instantiating urban type elements for illustrating a possible "realization" of a schematic design; this tool was not able to be developed on the chosen platform. I have also included some possible scenarios for using the modeling and information handling tools.by Joseph M. Knight.M.S

Performance of lactating dairy cattle housed in a four-row freestall barn equipped with three different cooling systems

Ninety-three multiparous Holstein cows averaging 130 days in milk (DIM) were utilized to evaluate three cooling treatments installed in separate pens of a four-row freestall barn in northeast Kansas during the summer of 1999. Treatments were: 1) a double row of 36-inch fans spaced at 24-ft intervals over the freestalls; 2) a single row of 36-inch fans spaced at 24-ft intervals over the freestalls and over the cow feed line; and 3) a double row of 36-inch fans spaced at 24-ft intervals over the freestalls and a single row over the feed line. Each pen was equipped with identical sprinkler systems over the cow feed line. The 85-day study evaluated milk production, body condition score, respiration rate, and feed intake of cows cooled with the systems. Cows cooled with fans over the freestalls and feed line produced more (P\u3c .05) milk (98.8 vs 93.9 lb/cow/day) than those cooled with fans only over the freestalls. Milk production was similar for cows cooled with fans over the freestalls and feed line, and doubling the number of fans over the freestalls had no apparent advantage. Cows in all treatments consumed similar amounts of feed, and those cooled only by fans over the freestalls tended to gain more body condition than cows in the other two treatments. Estimated increase in net income realized from using these cooling systems ranged from $3,500-6,100/year/pen.; Dairy Day, 1999, Kansas State University, Manhattan, KS, 1999

Performance of lactating dairy cattle housed in two-row freestall barns equipped with three different cooling systems

One hundred fifty-nine Holstein cows (66 primiparous and 93 multiparous) were assigned to each of three different cooling systems installed in two-row freestall barns on a northeast Kansas dairy. One barn was equipped with a row of five 48-inch fans mounted every 40 ft over the freestalls and a row of 10 36-inch fans mounted every 20 ft over the cow feed line. Another barn was equipped with five 48-inch fans mounted over the freestalls. Both of these barns were also equipped with identical sprinkler systems mounted over the feed line. The third barn was equipped with a row of five 48-inch fans mounted over the freestalls. In addition to the sprinklers over the feed line, additional sprinklers were mounted on the back alley of the third barn. Data were collected for an 85- day period to evaluate the three systems under heat stress during the summer of 1999. Cows cooled with these three systems produced similar amounts of milk and consumed nearly equal amounts of feed. Summer heat stress generally reduces milk production 20%, if cooling systems are not installed. Based on this estimated loss, these systems returned over $10,000/pen/year above ownership and operational cost. These results indicated that effective cooling in a two-row freestall barn includes a sprinkler system on the feed line and properly sized and spaced fans over the freestalls.; Dairy Day, 1999, Kansas State University, Manhattan, KS, 1999

Performance of lactating dairy cattle housed in two-row freestall barns equipped with three different cooling systems

One hundred fifty-nine Holstein cows (66 primiparous and 93 multiparous) were assigned to each of three different cooling systems installed in two-row freestall barns on a northeast Kansas dairy. One barn was equipped with a row of five 48-inch fans mounted every 40 ft over the freestalls and a row of 10 36-inch fans mounted every 20 ft over the cow feed line. Another barn was equipped with five 48-inch fans mounted over the freestalls. Both of these barns were also equipped with identical sprinkler systems mounted over the feed line. The third barn was equipped with a row of five 48-inch fans mounted over the freestalls. In addition to the sprinklers over the feed line, additional sprinklers were mounted on the back alley of the third barn. Data were collected for an 85- day period to evaluate the three systems under heat stress during the summer of 1999. Cows cooled with these three systems produced similar amounts of milk and consumed nearly equal amounts of feed. Summer heat stress generally reduces milk production 20%, if cooling systems are not installed. Based on this estimated loss, these systems returned over $10,000/pen/year above ownership and operational cost. These results indicated that effective cooling in a two-row freestall barn includes a sprinkler system on the feed line and properly sized and spaced fans over the freestalls