Optical technique for classification, recognition and identification of obscured objects

The capability to classify, recognize and to identify objects from spatially low resolution images has high significance in security related applications especially in a case that recognition of camouflaged object is required.In this paper we present a novel approach in which the scenery containing obscured objects which we wish to classify, recognize or identify is illuminated by spatially coherent beam (e.g. laser) and therefore secondary speckles pattern is reflected from the objects. By special image processing algorithm developed for this research and which is basically based upon temporal tracking of the random speckle pattern one may extract the temporal signature of the object. And right after, to use it for its classification (e.g. its separation from the other objects in the scenery), its recognition and identification even in a case that the imager provides poor spatial resolution that by itself does not allow doing the specified detection related operations.     

Converting homotopies to isotopies and dividing homotopies in half in an effective way

We prove two theorems about homotopies of curves on two-dimensional Riemannian manifolds. We show that, for any \({\epsilon > 0}\) , if two simple closed curves are homotopic through curves of bounded length L, then they are also isotopic through curves of length bounded by \({L + \epsilon}\) . If the manifold is orientable, then for any \({\epsilon > 0}\) we show that, if we can contract a curve \({\gamma}\) traversed twice through curves of length bounded by L, then we can also contract \({\gamma}\) through curves bounded in length by \({L + \epsilon}\) . Our method involves cutting curves at their self-intersection points and reconnecting them in a prescribed way. We consider the space of all curves obtained in this way from the original homotopy, and use a novel approach to show that this space contains a path which yields the desired homotopy.     

DNA-templated polymerization of side-chain-functionalized peptide nucleic acid aldehydes

The DNA-templated polymerization of synthetic building blocks provides a potential route to the laboratory evolution of sequence-defined polymers with structures and properties not necessarily limited to those of natural biopolymers. We previously reported the efficient and sequence-specific DNA-templated polymerization of peptide nucleic acid (PNA) aldehydes. Here, we report the enzyme-free, DNA-templated polymerization of side-chain-functionalized PNA tetramer and pentamer aldehydes. We observed that polymerization of tetramer and pentamer PNA building blocks with a single lysine-based side chain at various positions in the building block could proceed efficiently and sequence specifically. In addition, DNA-templated polymerization also proceeded efficiently and in a sequence-specific manner with pentamer PNA aldehydes containing two or three lysine side chains in a single building block to generate more densely functionalized polymers. To further our understanding of side-chain compatibility and expand the capabilities of this system, we also examined the polymerization efficiencies of 20 pentamer building blocks each containing one of five different side-chain groups and four different side-chain regio- and stereochemistries. Polymerization reactions were efficient for all five different side-chain groups and for three of the four combinations of side-chain regio- and stereochemistries. Differences in the efficiency and initial rate of polymerization correlate with the apparent melting temperature of each building block, which is dependent on side-chain regio- and stereochemistry but relatively insensitive to side-chain structure among the substrates tested. Our findings represent a significant step toward the evolution of sequence-defined synthetic polymers and also demonstrate that enzyme-free nucleic acid-templated polymerization can occur efficiently using substrates with a wide range of side-chain structures, functionalization positions within each building block, and functionalization densities.     

3′-Keto-1-nitro-2-phenylspiro[cyclopropane-3,2′-quinuclidine]: Synthesis and reactions with nucleophiles

3′-Keto-1-nitro-2-phenylspiro[cyclopropane-3,2′-quinuclidine] was synthesized by a two-step procedure from 2-benzylidenequinuclidin-3-one. Ring-opening reactions of the cyclopropane ring using a variety of N-, O-, and C-nucleophiles (amines, methoxide, nitromethanate, cyanide anions, and lithium diphenylcopper) were studied, and a general mechanism for the transformations is proposed.     

Thermal stability limits of proteins in solution and adsorbed on a hydrophobic surface

A coarse-grained Monte Carlo simulation is used to study thermal denaturation of small proteins in an infinitely dilute solution and adsorbed on a flat hydrophobic surface. Intermolecular interactions are modeled using the Miyazawa-Jernigan (MJ) knowledge-based potential for implicit solvent with the BULDG hydrophobicity scale. We analyze the thermal behavior of lysozyme for its prevalence of α-helices, fibronectin for its prevalence of β-sheets, and a short single helical peptide. Protein dimensions and contact maps are studied in detail before and during isothermal adsorption and heating. The MJ potential is shown to correctly predict the native conformation in solution under standard conditions, and the anticipated thermal stabilization of adsorbed proteins is observed when compared with heating in solution. The helix of the peptide is found to be much less stable thermally than the helices of lysozyme, reinforcing the importance of long-range forces in defining the protein structure. Contact map analysis of the adsorbed proteins shows correlation between the hydrophobicity of the secondary structure and their thermal stability on the surface.     

Novel heterocycles derived from 3-acyloxy- and 3-acetamidoquinuclidines

New quinuclidine derivatives with 3-spiro annelated oxathioline, furanone, and pyrrolinone heterocycles have been synthesized from 3-mesyloxy-, 3-acetoxy-, and 3-acetamidoquinuclidine-3-carbonitrile, respectively, by treatment with base. Treatment of 3-acetamidoquinuclidine-3-carbonitrile ( 3 ) with potassium hydride resulted in decyanation whereas alkyllithium reagents attacked the cyano group in 3 to produce the corresponding imines. Oxidative cyclization of the N-benzylated derivative of 3 with palladium acetate gave the tetracyclic compound 5-acetyl-1,4-ethano-1,2,3,4,5,6-hexahydrobenzo[c]-1,5-naphthyridine.     

A New Apparatus for Particle Impact Tests

Breakage and chipping of particles due to collision with a hard surface is a common occurrence in many conveying and handling systems, such as pneumatic conveying and jet‐mills. Studies of the breakage mechanism of particles due to impact and the effect of impact velocity and the number of impacts have been investigated in depth both experimentally and theoretically. In this paper, a new concept and apparatus are introduced for conducting particle impact tests. In most of the published test rigs, particles were accelerated towards a target. In our apparatus, the target moves and hits the particles. Using this concept, the machine can operate in a vacuum, which will reduce errors caused by air streams and turbulence. The performance of the new apparatus is analyzed and the breakage phenomenon is discussed, to some extent, for two materials. The results are presented in terms of the increase in the weight percentage of the feed broken and the decrease in the weight median size as the impact velocity or number of impacts increases.