Infrared method for in situ studies of polymer/surfactant adsorption on silica powders from aqueous solution

This article presents a general infrared spectroscopic method that enables the monitoring of the adsorption of surfactants and polyelectrolytes on high surface area silica particles from aqueous solution. The method is based on the use of a ZnSe internal reflection element (IRE) coated with a layer of titania particles. The titania surface is the converted to silica using atomic layer deposition with sequential addition of an amine catalyst, gaseous SiCl4, and water vapor. A minimum of three cycles is needed to produce a surface that mimics silica, as evidenced by the reaction of hexamethyldisilazane and zeta potential measurements. It is shown that the silicacoated titania particles on the ZnSe crystals are stable to flowing aqueous solutions below pH = 8 and can be used to study the dynamics of polymer/surfactant adsorption on silica.     

Magnetic Study of the His?Purkinje Conduction System in Man

It has recently been suggested that depolarization of the entire His-Purkinje conduction system of the heart produces a characteristic waveform in the surface electrocardiogram. The magnetic probe offers a different and, in some respects, advantageous means of observing such waveforms, and extensive records of the surface magnetic field generated by the human heart have been obtained for four normal subjects. A first-order SQUID gradiometer was employed havinAthe lowest noise level yet reported in any biomagnetic study (6 X 10-15 T/?Hz). Using an on-line computer, 100 beat averages were taken at 49 positions over the chest on a 1 in square grid. The fields observed have a characteristic symmetry and provide support for the suggestion that events associated with depolarization of the conduction system may be observed at the surface of the torso.     

Enteral feeding a structured lipid emulsion containing fish oil prevents the fatty liver of sepsis

Fish oils (FO) have been shown to reduce plasma triglycerides (TG). In this study we evaluated whether enteral feeding with a structured lipid emulsion (SLE) containing FO and medium-chain triglycerides (MCT) would prevent the hypertriglyceridemia and fatty infiltration of the liver that develops during sepsis. For five days, male Lewis rats (275–300 g) were fed intragastrically a nutritionally complete diet containing a SLE or a similar diet with a soybean oil emulsion (SOE) in place of the SLE. On the fifth day, sepsis was induced by intravenously injecting 8×10⁷ liveEscherichia coli colonies/100 g b.w.; 24 h later the control SLE, septic SLE, control SOE, and septic SOE rats were sacrificed. Diet, but not treatment, had a significant effect on serum TG and free fatty acids (FFA). Feeding the SLE reduced the plasma FFA of the control and septic rats by more than 50% in comparison to both control and septic rats fed the SOE. Soleus muscle activity of lipoprotein lipase from the septic SLE rats was 44% higher than the control SLE rats. Soleus muscle from the septic SLE rats also had a twofold greater activity of lipoprotein lipase than the septic SOE rats. TG did not accumulate in the livers of the septic rats fed SLE when compared to the control SLE rats and the rats fed the SOE. Livers from the septic rats fed the SLE had a third of the TG that were present in the livers from the septic rats fed the SOE. The rate of incorporation of [¹⁴C]oleate into liver lipids was significantly lower in septic rats fed SLE than in those fed the SOE. TG esterification was 70% lower in the septic rats fed SLE rather than the SOE. Our findings suggest that the SLE with FO and MCT has a role in the prevention of the sepsis-associated fatty liver by reducing the biosynthesis of liver TG.     

Auditory localization under sustained +Gz acceleration

The ability to localize a virtual sound source in the horizontal plane was evaluated under varying levels of sustained (+Gz) acceleration. Participants were required to judge the locations of spatialized noise bursts in the horizontal plane (elevation 0 degrees) during exposure to 1.0, 1.5, 2.5, 4.0, 5.5, and 7.0 +Gz. The experiment was conducted at the U.S. Air Force Research Laboratory's Dynamic Environment Simulator, a three-axis centrifuge. No significant increases in localization error were found between 1.0 and 5.5 +Gz; however, a significant increase did occur at the 7.0 +Gz level. In addition, the percentage of front/back confusions did not vary as a function of +Gz level. Collectively, these results indicate that the ability to localize virtual sound sources is well maintained at various levels of sustained acceleration. Actual or potential applications include the incorporation of spatial audio displays into the human-computer interface for vehicles that are operated in acceleration environments.     

An Au/Si hetero-nanorod-based biosensor for Salmonella detection

We present a novel and effective food-borne bacteria detection method. A hetero-structured silicon/gold nanorod array fabricated by the glancing angle deposition method is functionalized with anti-Salmonella antibodies and organic dye molecules. Due to the high aspect ratio nature of the Si nanorods, dye molecules attached to the Si nanorods produce an enhanced fluorescence upon capture and detection of Salmonella. This bio-functional hetero-nanorod detection method has great potential in the food safety industry as well as in biomedical diagnostics.     

Rapid and sensitive detection of respiratory virus molecular signatures using a silver nanorod array SERS substrate

A spectroscopic assay based on surface enhanced Raman scattering (SERS) using silver nanorod array substrates has been developed that allows for rapid detection of trace levels of viruses with a high degree of sensitivity and specificity. This novel SERS assay can detect spectral differences between viruses, viral strains, and viruses with gene deletions in biological media. The method provides rapid diagnostics for detection and characterization of viruses generating reproducible spectra without viral manipulation.     

A continuous-flow electrophile scavenger prepared by a simple grafting procedure

A versatile method for grafting reactive polymer onto macroporous polymer monoliths has been developed, and this method used to prepare a monolith containing primary amines. Reactive polymer was grafted onto residual olefins within the crosslinked monoliths using free-radical polymerization, and without requiring any pre-grafting activation. Capacities of the grafted monoliths were easily controlled by altering the composition of the grafting solution. Grafting N-vinylacetamide, followed by amide cleavage using hydrazine, afforded a monolith containing primary amine groups that was used for efficient continuous-flow scavenging of isocyanates, with 92% of phenyl isocyanate removed from solution in a reaction with a residence time of 49 min. High levels of scavenging required only a small excess of polymeric amine.     

A Parallel “String Matching Engine” for use in High Speed Network Intrusion Detection Systems

This paper describes a finite state machine approach to string matching for an intrusion detection system. To obtain high performance, we typically need to be able to operate on input data that is several bytes wide. However, finite state machine designs become more complex when operating on large input data words, partly because of needing to match the starts and ends of a string that may occur part way through an input data word. Here we use finite state machines that each operate on only a single byte wide data input. We then provide a separate finite state machine for each byte wide data path from a multi-byte wide input data word. By splitting the search strings into multiple interleaved substrings and by combining the outputs from the individual finite state machines in an appropriate way we can perform string matching in parallel across multiple finite state machines. A hardware design for a parallel string matching engine has been generated, built for implementation in a Xilinx Field Programmable Gate Array and tested by simulation. The design is capable of operating at a search rate of 4.7 Gbps with a 32-bit input word size.     

Simulating the structure and dynamics of human hair: Modelling,rendering and animation

We develop and present a new approach to modelling the characteristics of human hair, considering not only its structure, but also the control of its motion and a technique for rendering it in a realistic form. The approach includes a system for interactively defining the global positioning of the strands of hair on the head. Special attention is paid to the self shadowing of the hair. A mass/spring/hinge system is used to control a single strand's position and orientation. We demonstrate that this approach results in a believable rendition of the hair and its dynamics.