Biomimetic engineering of non-adhesive glycocalyx-like surfaces using oligosaccharide surfactant polymers

The external region of a cell membrane, known as the glycocalyx, is dominated by glycosylated molecules, which direct specific interactions such as cell-cell recognition and contribute to the steric repulsion that prevents undesirable non-specific adhesion of other molecules and cells. Mimicking the non-adhesive properties of a glycocalyx provides a potential solution to the clinical problems, such as thrombosis, that are associated with implantable devices owing to non-specific adsorption of plasma proteins. Here we describe a biomimetic surface modification of graphite using oligosaccharide surfactant polymers, which, like a glycocalyx, provides a dense and confluent layer of oligosaccharides. The surfactant polymers consist of a flexible poly(vinyl amine) with dextran and alkanoyl side chains. We show that alkanoyl side chains assemble on graphite through hydrophobic interaction and epitaxial adsorption. This constrains the polymer backbone to lie parallel to the substrate, with solvated dextran side chains protruding into the aqueous phase, creating a glycocalyx-like coating. The resulting biomimetic surface is effective in suppressing protein adsorption from human plasma protein solution.     

3-D repositioning and differential images of volumetric CT measurements

In quantitative computed tomography (QCT), time serial measurements are performed to detect a global bone density loss or to identify localized bone density changes. A prerequisite for an unambiguous analysis is the comparison of identical bone volumes. Usually, manual repositioning is too coarse. A mathematical procedure that allows matching two three-dimensional image volumes is presented. The algorithm is based on correlation techniques. The procedure has been optimized and applied to computer-tomographic 3-D images of the human knee. It has been tested with both artificially created and in vivo measured image data. Typical differential images calculated from real bone measurements are presented.     

Response of High Producing Dairy Cows in Early Lactation to the Feeding of Heat-Treated Whole Soybeans

Fifty-eight multiparous cows were assigned randomly to one of two rations. Control cows received a concentrate mixture that contained 20% soybean meal as the protein supplement, and the experimental cows were fed a concentrate that contained 25% heat-treated whole soybeans. The experimental period started 10 d after calving and continued for 15 wk.Experimental cows peaked later in milk production (5 vs. 3 wk) but at a higher level (39.8 vs. 39.4 kg/d) than control cows. Although milk production was less during the first 4 wk, experimental cows surpassed the controls in wk 5 and increased the advantage to 2.0 kg/cow/d by wk 15. For the total 15-wk period, average milk production was 37.0 kg/d for the experimental cows compared with 36.2 kg/d for the controls.Total dry matter intake, lactation efficiency, body weight, and reproductive performance were similar for both treatments. Cows fed heated soybeans consumed more metabolizable energy, 61.6 vs. 60.4 Mcal/d for controls. Cows on experimental diet also had higher free fatty acids in plasma (5.6 vs. 4.8 mg/100 ml) and triglycerides (25.0 vs. 20.9 mg/100 ml). The acetate-to-propionate ratio of rumen acids was significantly lower in the experimental group (3.36 vs. 3.61).     

Feedforward control for reduced run-to-run variation inmicroelectronics manufacturing

Increased manufacturing yields can be obtained by reducing process variation. One potential method to achieve lower process variance is through interprocess feedforward control. During feedforward control, a process recipe is adjusted to compensate for measured input deviations. The potential benefits of feedforward control include reduced run-to-run variance, rework, and scrap. Feedforward control has been used often in manufacturing. However, there are two problematic issues associated with feedforward recipe adjustment: 1) there is noise in the measurement tool and adjusting for inaccurate measurements could increase the variance and 2) it is difficult to alter one parameter in a manufacturing process without worsening other key parameters. In this paper, we will address both issues using a systems approach. Measurement noise poses a significant threat to the success of feedforward control. If the measurement noise is sufficiently large, the variance under feedforward control could exceed the variance with no control. To address this concern, we have integrated statistics theory into the feedforward controller design. This detunes the recipe adjustment based on the confidence in the accuracy of the sensor. These algorithms have the effect of filtering the noise from the measurement tool. In order to address the problem of altering one parameter without adversely affecting others, one can use a feedforward controller that selects a recipe from within a predefined set of allowable qualified recipes. We call this feedforward recipe selection control (FRSC). We have developed a design methodology for this type of controller. Preliminary versions of our design algorithms have been implemented into a graphical user interface (GUI)-based computer-aided design (CAD) environment. This interactive software package guides the engineer through the design of feedforward controllers using process data as inputs     

Making reuse pay: the SIDPERS-3 RAPID Center

The US Army Information Systems Engineering Command (ISEC), which develops and maintains Standard Army Multicommand Information Systems (STAMIS), asked the author's company to examine the feasibility of the RAPID software library concept, to assess the potential for software reuse in traditional MIS applications. (RAPID is an acronym for Reusable Ada Packages for Information system Development.) The author summarizes the findings of this work, and discusses the RAPID Center, which is currently being developed to support ISEC's software reuse program and to apply the results from the RAPID investigation. The SIDPERS-3, the third and latest version of the US Army's Standard Installation/Division Personnel System, serves as a testbed for the RAPID Center and related issues of software reusability     

Use of a combination of propylene glycol and niacin for subclinical ketosis

Twenty-six cows that developed positive milk tests for ketosis in early lactation were randomly assigned to one of three groups: control, propylene glycol (125 ml/d), or 125 ml of propylene glycol plus 12 g of niacin daily. Treatments were administered for 7 d. Changes in milk production, milk composition, and feed intake were similar for all three groups. None of the cows in any of the groups developed clinical ketosis. During the 14-d monitoring period from the start of treatment there were similar increases in blood glucose in all groups. Declines in plasma beta-hydroxybutyrate and free fatty acids over the period were also similar for all treatments. Results reinforce the concept that optimum feeding and management reduces the need for additives for ketosis control.     

Fast Contour Detection Algorithm for High Precision Quantitative CT

An algorithm for the automatic contour detection of objects in CT images is presented. It requires little memory space, allows easy incorporation of different types of local digital filters, and is fast. Typical computation time with a minicomputer is less than one second. An implementation of the algorithm for the detection of bone contours from low dose CT images is given as an example.