Structure of the twin-arginine signal-binding protein DmsD from Escherichia coli

The translocation of folded proteins via the twin-arginine translocation (Tat) pathway is regulated to prevent the futile export of inactive substrate. DmsD is part of a class of cytoplasmic chaperones that play a role in preventing certain redox proteins from premature transport. DmsD from Escherichia coli has been crystallized in space group P4_12_12, with unit-cell parameters a = b = 97.45, c = 210.04 Å, in the presence of a small peptide. The structure has been solved by molecular replacement to a resolution of 2.4 Å and refined to an R factor of 19.4%. There are four molecules in the asymmetric unit that may mimic a higher order structure in vivo. There appears to be density for the peptide in a predicted binding pocket, which lends support to its role as the signal-recognition surface for this class of proteins

Thin film thermoelectric devices as thermal control coatings: A study

Peltier effect, Thomson effect, and Seeback effect are utilized in design of thermal control coating that serves as versatile means for controlling heat absorbed and radiated by surface. Coatings may be useful in extreme temperature environment enclosures or as heat shields

The Internet and the Future of Financial Services: Transparency, Differential Pricing and Disintermediation

The Internet has had a profound effect on the financial service sector, dramatically changing the cost and capabilities for marketing, distributing and servicing financial products and enabling new types of products and services to be developed. This is especially true for retail financial services where widespread adoption of the Internet, the standardization provided by the world-wide web, and the low cost of Internet communications and transactions have made it possible to reach customers electronically in ways that were prohibitively costly even 5 years ago; indeed, pre-Internet attempts at the online distribution of retail financial services were outright failures in the mid-1980s. The concurrent growth and de-facto standardization of Internet-enabled personal financial management software (e.g., Quicken and Microsoft Money) have also contributed to an increasing array of low cost and potentially richer ways to provide information and transaction services to customers. The growth in Internet-enabled products and service has been rapid in some sectors and slower in others. Retail brokerage has seen a dramatic change with more than 15% (Salomon Smith Barney, 2000) of brokerage assets now managed in on-line trading counts, and substantially more if "traditional" brokerage accounts and mutual funds with on-line access are included. Similarly, approximately 10 million US customers currently use on-line banking (O'Brien, 2000) and 39 of the top 100 banks offer fully functional internet banking (ePayNews, 2000). Many banks and brokerages are on their second or third release of their on-line delivery platform. Credit cards, while not radically transformed in operational aspects of the business, have begun to have some volume of new origination on-line. In addition, leading credit card companies such as Capital One Financial have been some of the largest "traditional" companies in the use of Internet advertising (see www.adrelevance.com, 1999). More regulated and complex financial products such as mortgages and insurance have had some origination volume on the Internet (an estimated $17Bn of mortgages will be originated and ~$400mm in insurance premiums will be sold online in 2000). For these sectors, the adoption of on-line origination has been much slower and concentrated in entrants, rather than incumbent firms. However, despite the small level of originations, the Internet has become a significant and growing source of product information - it is estimated that about 10% of insurance customers and 15% of mortgage customers have used the internet to shop for these products (Forrester, 1998; McVey, 2000). This may ultimately affect product purchase and pricing structure, irrespective of the delivery channel. Internet companies have also played a role in many other segments of the industry such as financial information and news, rating and comparison services, and even some areas where one might think the Internet would have a less significant role, such as financial planning and investment banking. While the continued growth rates are uncertain and the penetration for the more complex products has not yet been shown to be widespread, it is safe to conclude that the Internet will play a significant role in consumer financial services for a large subset of customers, and that this role will be significantly different across different sub-sectors of the financial industry. In discussions of the Internet impact on the financial services sector, the emphasis has often been placed on the direct cost-saving effects of using the Internet to provide transaction services. These potential cost savings are indeed significant and in the long term may lead to significant creation of value. However, there also substantial barriers to realizing much of this value. In some industries, such as the credit card industry, many of the potential gains from automation have already been realized, and in others, the gains may be concentrated in only a few areas of the value chain. For products which are sold through branches or agents (banking, mortgage and insurance), realization of cost savings will require a difficult and time consuming redesign of the retail delivery system. Finally, many of these efficiencies are accompanied by improved customer convenience. To the extent that consumers respond by consuming more services, particularly those that generate costs but not revenue, overall costs may not be substantially reduced. This has been the experience of previous innovations in retail financial service delivery such as automated teller machines (ATMs). Computers, and more recently the Internet, are best described as "general purpose technologies" (Brynjolfsson and Hitt, 2000), like the electric motor or the telegraph (Bresnehan and Trajtenberg, 1995). For general purpose technologies, most of the economic value they create is associated with their ability to enable complementary innovations in organization, market structure, and products and services. However, at the same time, these complementary changes are often disruptive to the existing structure of an industry (Tushman and Anderson, 1986; Bower and Christensen, 1995), leading to significant redistribution of value among industry participants and between producers and consumers. To understand the true impact of the Internet on the financial service industry, it is therefore necessary to identify how the Internet affects the critical drivers of industry structure, and how it enables or necessitates changes in products and services. This will necessarily be difficult, as it is hard to isolate the contribution of the Internet separately from the effects of other complementary innovations, and to distinguish Internet effects from other of long-term industry trends and exogenous factors. While obtaining precise numerical estimates of the productivity effects will be hard, in many cases the direction and general magnitude of the impact on productivity, profitability and consumer surplus (consumer value) will be clear. We see three principal issues that will determine the transformation of retail financial services: Transparency, or the ability of all market participants to determine the available range of prices for financial instruments and financial services; Differential pricing, in which finer and finer distinctions must be made among groups of customers, setting their prices based upon the revenue streams they generate, the costs to serve them, and their resulting profitability; Disintermediation or bypass, in which net-based direct interaction eliminates the role previously enjoyed by financial advisors, retail stock brokers, and insurance agents. Each of these will affect the roles to be played by financial service providers, the sources of profits available to them, and the strategies they may choose to pursue in order to earn those profits. However, different financial products will be affected differently by each of these issues in both the nature and the magnitude of the effect. In addition, these factors are often interdependent - for example, differential pricing is often a necessary response to increasing price transparency to prevent erosion of margins, and the ability to deliver sophisticated (although typically not complex) pricing strategies to customers may be affected by the incentives and structure of the distribution system. For these reasons, we will organize the remainder of the paper around the discussion of these effects as they apply within different sectors in financial services. The emphasis of our analysis will be on the primary sectors in retail financial services: credit cards, deposit banking, mortgages, brokerage, and insurance. Our focus is the retail segment because it has been the most radically transformed by the Internet to date, primarily because the retail business has the most to benefit from the reduction in customer interaction costs, the ability to reach mass markets, and the reduction in the role of geography in determining the strategies of financial services providers. Much of the computing- and communications-enabled transformation in the relationships among financial institutions or between financial institutions and consumers of wholesale financial services (for example, brokerage houses and exchanges, or large firms and their commercial lenders) have already occurred or were well underway before the Internet was commercialized. For these markets, the economics of computing and networking were still favorable under previous generations of technology. Many of the commercial financial services that are likely to be transformed by the Internet, at least in the medium term (3-5 years), are those that closely resemble retail services (such as commercial mortgage, short term lending, leasing, cash management, and the like). That is not to say that business to business (B2B) e-commerce opportunities do not exist in the financial sector - only that many of the medium term opportunities that are directly a result of the Internet are closely analogous to changes in the retail sector, and the others are probably more closely related to organizational and market innovation rather than a result of ubiquitous and low-cost communications technology.

Effects of external environments on the short beam shear strength of filament wound graphite/epoxy

Filament wound graphite/epoxy samples were immersed in seawater, deionized water, and toluene at room temperature and 80 deg C for 5, 15, and 43 days, and in methanol at room temperature for 15 and 43 days. The percent weight gains and short beam shear strengths were determined after environmental exposure. Samples immersed in deionized water and seawater had higher percent weight gains than those immersed in toluene at room temperature and 80 deg C. The percent weight gains for samples immersed in methanol at room temperature were comparable to those of deionized water and seawater immersed samples. A comparison of percent decreases in short beam shear strengths could not be made due to a large scatter in data. This may indicate defects in samples due to machining or variations in material properties due to processing

PETROFABRIC AND GEOCHEMICAL ANALYSIS OF THE GREAT SMOKY -- SNOWBIRD GROUP CONTACT, WESTERN BLUE RIDGE, NORTH CAROLINA AND TENNESSEE

Detailed structural and petrographic analysis of the Greenbrier Fault (GBF) reveal different fold and fabric styles and generations preserved in the Great Smoky Group (GSG) hanging wall and Snowbird Group (SG) footwall. Four planar fabrics (S0, S1, S2, and S3) are completely overprinted within meters of the contact by shear zone-related fabrics. Bedding (S0) is defined by planar laminations in the SG siltstones. S1 is weak, not associated with folding of S0, and defined locally by sub-parallel alignment of biotite. S2 (slaty cleavage) is deflected into a disjunctive planar (in GSG) or continuous planar (in SG) S3 foliation characterized by mica formation and dynamic recrystallization of quartz. Metamorphic microstructures indicate lower greenschist to upper amphibolite facies Taconian metamorphism is syn- to post-S2, and pre-S3. Local lower greenschist facies retrograde metamorphism precedes S3 formation. A meter scale, ductile mesoscopic shear zone in SG at the GSG-SG contact is characterized by S/C fabric; this is the youngest deformational event and postdates retrograde mineral assemblages indicating postmetamorphic motion along the contact. Premetamorphic fault fabrics indicative of GSG thrusting onto the SG were absent or completely reconstituted during metamorphism and deformation. The Metcalf phyllite and Pigeon siltstone were also compared to test the hypothesis that the Metcalf phyllite is tectonized Pigeon siltstone. Major and trace element abundances are similar between the lithologies, with the exception of depletion of Ca, Na and Zr in the Metcalf. The system appears to have been open with respect to these elements. It is concluded that the Metcalf phyllite is the tectonized equivalent of the Pigeon siltstone based on lateral continuity, the strong macroscopic and microscopic resemblance of weakly deformed Metcalf to the Pigeon, similar mean values and ranges in major, minor, and trace elements, and identical rock densities

Process for producing tris s(n-methylamino) methylsilane

A method of producing tris (N-methylamine) methylsilane is described including the steps of forming and cooling a liquid solution of methylamine in an inert solvent and under an inert atmosphere at a temperature of about -30 C and slowly adding a quantity of methyltricholorosilane while maintaining said temperature. The reaction mixture is then heated for about 60 minutes at a temperature of about 40 C, followed by filtering the solid portion from the liquid portion. The liquid is distilled to remove the solvent, resulting in a high yield of tris (N-methylamine) methylsilane

Strain Typing Mycobacterium marinum from Outbreaks at Zebrafish Research Facilities

Zebrafish (Danio rerio) are used as model organisms for biological research due to their rapid and transparent development and high fecundity amongst other reasons. Research has expanded beyond embryonic studies, with adult fish used for longer-term studies such as human disease and senescence. Zebrafish are often housed at high density in large colonies. As with any similar husbandry situation, diseases can occur, with impacts that range from morbidity to premature mortality costing researchers time and money. Understanding the impact of underlying diseases in zebrafish is crucial, particularly for long-term studies where chronic infections may confound results. One such disease problem is mycobacteriosis, caused by numerous Mycobacterium species. Mycobacteria likely spread when fish are exchanged between facilities with no precautions for biosecurity. Bacteria can also persist in the water and live on surface biofilms, making control more difficult. Mycobacterium marinum is one species that is of interest because it is highly virulent, contributing to serious outbreaks. It is also a concern for occupational health because it can cause skin infections in humans. To better understand the spread of mycobacteriosis caused specifically by M. marinum, strain typing was conducted to categorize isolates from seven different zebrafish facilities throughout the United States. For strain typing a variable number of tandem repeat assay was used. This technique was adapted using fluorescently labeled primers followed by fragment analysis in order to increase throughput and repeatability. These results were then used to determine if any epidemiological linkages exist between facilities experiencing outbreaks

Get5 Carboxyl-terminal Domain Is a Novel Dimerization Motif That Tethers an Extended Get4/Get5 Complex

Tail-anchored trans-membrane proteins are targeted to membranes post-translationally. The proteins Get4 and Get5 form an obligate complex that catalyzes the transfer of tail-anchored proteins destined to the endoplasmic reticulum from Sgt2 to the cytosolic targeting factor Get3. Get5 forms a homodimer mediated by its carboxyl domain. We show here that a conserved motif exists within the carboxyl domain. A high resolution crystal structure and solution NMR structures of this motif reveal a novel and stable helical dimerization domain. We additionally determined a solution NMR structure of a divergent fungal homolog, and comparison of these structures allows annotation of specific stabilizing interactions. Using solution x-ray scattering and the structures of all folded domains, we present a model of the full-length Get4/Get5 complex

Feasibility of Using Saltcedar as a Filler in Injection-Molded Polyethylene Composites

Saltcedar (Tamarix ramosissima) was investigated for use as a filler in wood-plastic composites (WPCs). The mineral content, water-soluble extractive content, and thermal stability of saltcedar flour were compared with those of a commercial pine wood flour. The wood flours were compounded with plastic, and the viscosities of the composite melts containing the two species were compared. Injection-molded composites produced from the compounded material were evaluated for mechanical performance and weatherability. Saltcedar flour had more minerals and water-soluble extractives than pine flour, which resulted in lower thermal stability, but also lower melt viscosity when compounded with high-density polyethylene. Injection-molded WPCs made from unextracted saltcedar performed similarly to those made from pine in accelerated weathering tests, but their mechanical properties were generally lower. The flexural modulus of elasticity increased when extracted wood flour was used, especially for the saltcedar composites. However, color stability and flexural strength changed little. Producing WPCs from these composites is possible, although economically feasible applications that use the advantageous properties of these species and that can tolerate or address the less desirable ones need to be identified and demonstrated