A Biologically Active Surface Enzyme Assembly that Attenuates Thrombus Formation

Activation of hemostatic pathways by blood‐contacting materials remains a major hurdle in the development of clinically durable artificial organs and implantable devices. Here, it is postulated that surface‐induced thrombosis may be attenuated by the reconstitution onto blood contacting surfaces of bioactive enzymes that regulate the production of thrombin, a central mediator of both coagulation and platelet activation cascades. Thrombomodulin (TM), a transmembrane protein expressed by endothelial cells, is an established negative regulator of thrombin generation in the circulatory system. Traditional techniques to covalently immobilize enzymes on solid supports may modify residues contained within or near the catalytic site, thus reducing the bioactivity of surface enzyme assemblies. In this report, a molecular engineering and bioorthogonal chemistry approach to site‐specifically immobilize a biologically active recombinant human TM fragment onto the luminal surface of small diameter prosthetic vascular grafts is presented. Bioactivity and biostability of TM modified grafts is confirmed in vitro and the capacity of modified grafts to reduce platelet activation is demonstrated using a non‐human primate model. These studies indicate that molecularly engineered interfaces that display TM actively limit surface‐induced thrombus formation.     

High performance polyaniline containing coating system for wet surfaces

Application of paint coatings on wet surfaces is rather difficult due to poor adhesion of coatings. For painting of wet surfaces, moisture curable coating systems based on epoxy resin and ketimine are found to be useful. Hence a study has been made on the corrosion protection ability of coating on wet surfaces using epoxy resin, ketimine and polyaniline. Paints with 20–30% PVC were prepared and applied over the wet steel surface and the corrosion protection performance of the coating was found out by salt spray and electrochemical impedance spectroscopic techniques. Coating with 20% PVC is found to offer very high protection since the impedance values are remained at greater than 10⁹ Ω cm² after immersion and salt spray tests.     

Corrosion protection of iron by benzoate doped polyaniline containing coatings

Polyaniline containing organic coatings based on vinyl and acrylic resins are found to protect iron in acid and neutral media. Since dopants play an important role in forming salts with iron, a study has been made on the effect of benzoate doped polyaniline on the corrosion protection of iron by polyaniline–vinyl coatings in acid and neutral media. EIS studies have been made on the corrosion protection performance of vinyl coating on steel with 1% polyaniline in 0.1N HCl and 3% NaCl up to 100 days of exposure. It has been found that benzoate doped polyaniline containing coating has found to offer more protection in neutral media than that in acidic media due to passivating ability of benzoate ions in neutral solution, along with iron–polyaniline complex.     

Characterization and bacterial toxicity of lanthanum oxide bulk and nanoparticles

This study evaluated the bacterial toxicity of lanthanum oxide micron and nano sized particles using shake flask method against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. Particle size, morphology and chemical composition were determined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Re-sults indicated that lanthanum oxide nanoparticles showed antimicrobial activity against Staphylococcus aureus, but not against Escherichia coli and Pseudomonas aeruginosa. It was speculated that lanthanum oxide produced this effect by interacting with the gram-positive bacte-rial cell wall. Furthermore, lanthanum oxide bulk particles were found to enhance the pyocyanin pigment production in Pseudomonas aeruginosa.)     

Comparing data streams using Hamming norms (how to zero in)

Massive data streams are now fundamental to many data processing applications. For example, Internet routers produce large scale diagnostic data streams. Such streams are rarely stored in traditional databases and instead must be processed "on the fly" as they are produced. Similarly, sensor networks produce multiple data streams of observations from their sensors. There is growing focus on manipulating data streams and, hence, there is a need to identify basic operations of interest in managing data streams, and to support them efficiently. We propose computation of the Hamming norm as a basic operation of interest. The Hamming norm formalizes ideas that are used throughout data processing. When applied to a single stream, the Hamming norm gives the number of distinct items that are present in that data stream, which is a statistic of great interest in databases. When applied to a pair of streams, the Hamming norm gives an important measure of (dis)similarity: the number of unequal item counts in the two streams. Hamming norms have many uses in comparing data streams. We present a novel approximation technique for estimating the Hamming norm for massive data streams; this relies on what we call the "l/sub 0/ sketch" and we prove its accuracy. We test our approximation method on a large quantity of synthetic and real stream data, and show that the estimation is accurate to within a few percentage points.     

First- and Second-Order Diffusive Methods for Rapid, Coarse, Distributed Load Balancing

We consider the following general problem modeling load balancing in a variety of distributed settings. Given an arbitrary undirected connected graph G=(V,E) and a weight distribution w ⁰ on the nodes, determine a schedule to move weights across edges in each step so as to (approximately) balance the weights on the nodes. We focus on diffusive schedules for this problem. All previously studied diffusive schedules can be modeled as w ^t+1 = M w ^t where w ^t is the weight distribution after t steps and M is a doubly stochastic matrix. We call these the first-order schedules. First-order schedules, although widely used in practice, are often slow. In this paper we introduce a new direction in diffusive schedules by considering schedules that are modeled as: w ¹ =M w ⁰ ;w ^t+1 =β M w ^t + (1-β) w ^t-1 for some appropriate β; we call these the second-order schedules. In the idealized setting of weights being real numbers, we adopt known results to show that β can be chosen so that the second-order schedule involves significantly fewer steps than the first-order method for approximate load balancing. In the realistic setting when the weights are positive integers, we simulate the idealized schedules by maintaining I Owe You units on the edges. Extensive experiments with simulated data and real-life data from JOSTLE, a mesh-partitioning software, show that the resultant realistic schedule is close to the idealized schedule, and it again involves fewer steps than the first-order schedules for approximate load balancing. Our main result is therefore a fast algorithm for coarse load balancing that can be used in a variety of applications. Received October 1996, and in final form January 1998.     

An application of compiler technology to the year 2000 problem

This paper describes our experience in developing techniques for repairing date affected programs using standard compiler technology. Starting with date‐ness information of certain variables based on their declarations, we propagate this information through all possible control paths, using date inference rules to traverse across individual statements. Our approach is fine grained enough to infer the date‐ness of each occurrence of a variable. After detecting date‐ness of variables, we renovate programs by applying a transformation using base year strategy. These techniques have been implemented as a tool set for renovating date affected COBOL programs. Copyright © 1999 John Wiley & Sons, Ltd.     

Detoxication and Theranostic Aspects of Biosynthesised Zinc Oxide Nanoparticles for Drug Delivery

Bioactive materials obtained from plant bio-resources offer immense attention for development and production of nanotech-nology enabled products for biomedical applications.In the present study,Ficus hispida leaf extract(FHLE)was used as a stabilising agent for the environmentally benign synthesis of zinc oxide nanoparticles(ZnO-NPs)which were investigated for prospective versatile applications(anticancer and photocatalytic activities).The formation of ZnO-NPs was confirmed by UV-visible spectra.Wurtzite(hexagonal)form of the herb-assisted synthesised ZnO-NPs with particle size ranging from 20 to 200 nm was confirmed by transmission electron microscopy(TEM)analysis.In vitro analysis was carried out against Dalton's lymphoma ascites(DLA)cell lines by trypan blue assay,the results revealed 96％inhibition at concentration of 200 μg ml-1,and the photodegradation experiments carried out for degradation of Congo red revealed complete degradation of the dye after 70 min of exposure to UV light.     

Corrosion protective performance studies of coating systems in soda ash chemical industry

Organic coatings are widely used to protect steel structures. The performance of the coating system depends upon the atmospheric conditions prevailing in the chemical industry. Before selecting a protective system, the corrosivity of the atmosphere has to be determined. A study has been made for selecting a good protective system for a soda ash chemical industry where chemicals such as soda ash, sodium chloride and hydrochloric acid are produced by using sea water as a raw material. Under these conditions, after collecting the corrosivity rate at various places of industrial areas, coated steel panels with various paint combinations were exposed in different sites for a period of 2 years. The performance of the coatings was monitored by EIS studies besides visual inspection. The corrosion protection performance of the various coating systems of zinc rich primer with different types of under coats and top coats has been studied and the results are reported.     

Benign Approach of Plant-Derived Inhibitor: Assessing Their Anticorrosive Activity on Mild Steel in Acidic Media

Journal of Failure Analysis and Prevention - The dissolution behavior of mild steel in 2 M H2SO4 with various concentrations of Borassus Flabellifer Seed Food (BFSF), Musa Paradisiaca Dry...