FTIR Microscopic Studies on Normal, Polyp, and Malignant Human Colonic Tissues

Fourier-Transform Infrared Spectroscopy (FTIR) employs a unique approach tooptical diagnosis of tissue pathology based on the characteristic molecularvibrational spectra of the tissue. The biomolecular changes in the cellularand sub-cellular levels developing in abnormal tissue, including a majorityof cancer forms, manifest themselves in different optical signatures, whichcan be detected in infrared microspectroscopy. This report has two parts. Inthe first part, we report studies on normal, premalignant (polyp) andmalignant human colonic tissues from three patients with different stages ofmalignancy. Our method is based on microscopic infrared study (FTIR-microscopy)of thin tissue specimens and a direct comparison with traditional histopathologicalanalysis, which serves as a gold reference. The limited dataavailable showed normal colonic tissue has a stronger absorption thanpolypoid tumor and cancerous types over a wide region in a total of 100measurements. Detailed analysis showed that there is a significant decreasein total carbohydrate, phosphate and possibly creatine contents for polyp andcancerous tissue types in comparison to the controls. The same trend is maintainedin seven other patients studied. The second part consists of an analysis showingthe influence of various independent factors such as age, sex and grade of malignancy. Ourpreliminary results suggest that among the above three factors, age and gradeof malignancy have significant effect on the metabolites level, but sex has onlyminor effect on the measured spectra. Initial results on Linear DiscriminantAnalysis (LDA) showed good classification between normal and malignant cellsof human colonic tissues.     

SDS-PAGE under focusing conditions: an electrokinetic transport phenomenon based on charge compensation

A novel method is reported for mass separation of proteins, based on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Unlike conventional SDS-PAGE, in which separation by mass of SDS-laden polypeptide chains is obtained in constant concentration or porosity gradient gels, the present method, called "SDS-PAGE focusing", exploits a "steady-state" process by which the SDS-protein micelles are driven to stationary zones along the migration path against a gradient of positive charges affixed to the neutral polyacrylamide matrix. As the total negative surface charge of such complexes matches the surrounding charge density of the matrix, the SDS-protein complex stops migrating and remains stationary, as typical of steady-state separation techniques. As a result of this mechanism, the proteins are separated in an unorthodox way, with the smaller proteins/peptides staying closer to the application point and larger proteins migrating further down toward the anodic gel end. This results in a positive slope of the Mr vs migration plot, vs a negative slope in conventional SDS-PAGE. Moreover, such a plot is linear (by design), whereas in standard SDS-PAGE it is semi- or even double logarithmic. Particularly advantageous appears the ability of the present method to fine-tune the separation of small-size fragments and tryptic digests, where conventional SDS-PAGE usually fails. Additionally, by exploiting constant plateaus of charges, rather than gradients, it is possible to amplify the separation between species having closely spaced Mr values, down to a limit of approximately 150 Da. This increases the resolution by at least 1 order of magnitude as compared with standard SDS-PAGE, where for a proper separation of two adjacent species, an Mr increment of approximately 3000 Da is needed.     

Saving Space by Fully Exploiting Invisible Transitions

Checking that a given finite state program satisfies a linear temporal logic property suffers from the state explosion problem. Often the resulting lack of available memory is more significant than any time limitations. One way to cope with this is to reduce the state graph used for model checking. We present an algorithm for constructing a state graph that is a projection of the program's state graph. The algorithm maintains the transitions and states that affect the truth of the property to be checked. Especially in conjunction with known partial order reduction algorithms, we show a substantial reduction in memory over using partial order methods alone, both in the precomputation stage, and in the result presented to a model checker. The price of the space reduction is a single additional traversal of the graph obtained with partial order reduction. As part of our space-saving methods, we present a new way to exploit Holzmann's Bit Hash Table, which assists us in solving the revisiting problem.     

Concentration of Bacillus spores by using silica magnetic particles

Silica particles are mainly used for the concentration of nucleic acid for diagnostic purposes. This is usually done under acidic or chaotropic conditions that will demolish most of the living organisms and prevent the application of other diagnostic tests. Here we describe the development of a method for the capturing and concentration of Bacillus spores using silica magnetic particles to enable fast and sensitive detection. We have shown that capturing various Bacilli spores via silica magnetic particles is limited, with large differences between spore batches (42 +/- 25%). The hydrophobic exosporium layer of spore limits the capture by the hydrophilic silica beads. Partial removal of Bacillus exosporium increases capture efficiency. To increase capturing efficiency without harming the spores' viability, a cationic lipid, didecyldimethylammonium bromide (DDAB), was used as a coat for the negatively charged silica particles. DDAB treatment increased capture efficiency from 42% to more than 90%. Using this method, we were able to capture as few as 100 Bacillus anthracis spores/mL with 90% efficacy. Release of captured spores was achieved by the addition of albumin. The capture and release processes were verified by plating and by flow cytometry using light scatter analysis. The method is simple, efficient, easy to operate, and fast.     

Outbreak of subclinical mastitis in a flock of dairy goats associated with atypical Staphylococcus haemolyticus

Staphylococcus haemolyticus is a pathogen frequently isolated from dairy cows and small ruminants. However, it always appears in only a few animals and not as a major pathogen. Recently, in a dairy goat herd of approximately 250 milking animals, 25.6% (46/180 goats) had milk cultures with atypical highly mucoid colonies accompanied by elevated somatic cell counts. The isolates were identified as Staph. haemolyticus. The present study describes the steps used in an attempt to identify the bacterium and to compare it with other coagulase-negative staphylococci (CNS) including Staph. haemolyticus. Species identification performed with the API STAPH-IDENT 32 kit showed >99.4% identity confirmed by 16S rDNA sequencing tests. Microscopically the atypical Staph. haemolyticus strains showed unique cuboidal tetrad clusters reminiscent of those of the genus Sarcina. The outbreak caused by an atypical CNS underlines the need for accurate biochemical and genetic methods for ultimate identification of CNS to the species level.     

Nanoinduced morphology and enhanced properties of epoxy containing tungsten disulfide nanoparticles

Closed‐cage (fullerene‐like) nanoparticles (NPs) of WS₂ are currently produced in large amounts and were investigated as additives to thermoplastics and thermosetting polymers. The nanoinduced morphology and the resulting enhanced fracture toughness of epoxy/WS₂ nanocomposites were studied. The morphology of the epoxy nanocomposites was induced by controlled WS₂ surface chemistry. The WS₂ NPs used were either untreated or chemically treated with acryloxy, which is compatible, and alkyl silane, which is incompatible, respectively, with the epoxy matrix. In the case where the acryloxy silane was used to treat the WS₂ particles, good dispersion and compatibility were obtained in the epoxy resin_. Moreover, a distinct nodular morphology was induced on fracture as a result of nucleation by the compatible NPs. In the case where the alkyl silane treatment was used cavitation morphology was induced, following mechanical loading, which is the result of incompatibility with the epoxy resin. The fracture toughness results showed an increase of 70% for nanocomposites contains alkyl‐treated WS₂ compared with the neat epoxy. Modeling of the nodular morphology enabled the determination of optimal concentration of the WS₂ in epoxy (0.3% by weight). Two main fracture mechanisms were observed, crack bowing around the nodular boundaries in the case of compatibility between the nanoparticle and the epoxy and particle‐induced cavitation in the case of incompatibility, respectively. These results are of significant importance both for epoxy‐based adhesives and fiber composites. POLYM. ENG. SCI., 53:2624–2632, 2013. © 2013 Society of Plastics Engineers     

ETK-an operational explosive testing kit

A chemical kit for field determination of traces of explosives on hands of suspects is described. The system involves three components: dry sampling devices (‘‘detection buttons''), and two tubes of chemical reagents. It detects virtually all the common military explosives, and there is also an option to detect home-made explosives based on inorganic fertilizers. Detection is based on two well known chemical reactions for which optimal conditions have been developed. In stage I polynitro aromatics are detected by the formation of colored Meisenheimer complexes. In stage II organic nitrates and nitramines are consequently detected by modified Griess test.     

Surface properties of Ca,Ti-doped CeO2 and their influence on the reverse water-gas shift reaction

CeO₂-based materials can be found in a variety of catalytic processes, including the reverse water-gas shift (RWGS) reaction. Nevertheless, the interaction of molecular gases with the surfaces of such materials is still not clear. Recently, some progress was reported on the incorporation of neodymium (Nd) and calcium (Ca) into ceria and their effect on H₂O and CO₂ adsorption. Titanium (Ti), which has a much smaller ionic radius, has the ability to change the interaction landscape, both as a co-dopant to Ca and as a sole dopant in the CeO₂ system. In this study, the interactions of environmental gases (i.e., water vapor and CO₂) on the surface of Ti-doped CeO₂ and Ca,Ti co-doped CeO₂ were investigated. Ti addition to CeO₂ was shown to decrease water vapor uptake by up to 25% all while maintaining similar heats of adsorption. In the case of CO₂ adsorption, Ti addition to CeO₂ had lowered the uptake by more than 50% as well as lowering the heat of adsorption. Co-doping with Ti and Ca showed small decrease in H₂O uptake accompanied with increased heat of adsorption. For CO₂, the changes to the uptake and energetics were small and did not indicate a specific trend. The RWGS catalytic performance showed improvement by the addition of Ti in certain levels. The relationship between the doping, surface properties, gas-surface interactions, and catalytic performance is discussed.     

Noisy image restoration by cost function minimization

Implementation of a new approach to the nonlinear noisy image restoration problem, which is feasible for large images, is described. The approach is based on a vector space representation of images and on using the conjugate gradient algorithm to solve a least squares minimization problem. Computer simulations yield good results with relatively little computational cost.     

Asymptotic and finite element approximations for heat transfer in rotating compressible flow over an infinite porous disk

The laminar boundary layer equations for the compressible flow due to the finite difference in rotation and temperature rates are solved for the case of uniform suction through the disk. The effects of viscous dissipation on the incompressible flow are taken into account for any rotation rate, whereas for a compressible fluid they are considered only for a disk rotating in a stationary fluid. For the general case, the governing equations are solved numerically using a standard finite element scheme. Series solutions are developed for those cases where the suction effect is dominant. Based on the above analytical and numerical solutions, a new asymptotic finite element scheme is presented. By using this scheme one can significantly improve the pointwise accuracy of the standard finite element scheme.