Functional cyclodextrins. 1. Chloroacetylated cyclodextrins

The paper discusses the synthesis of the chloroacetylated derivatives of α-, β- and γ-cyclodextrins. These novel functionalized products can be used both in the synthesis of some conjugates with bioactive substances by covalent bonding and/or for inclusion of hydrophobic compounds.     

DNA interaction of the CcrM DNA methyltransferase: a mutational and modeling study

Caulobacter crescentus CcrM is a DNA-(adenine N6)-methyltransferase that methylates adenine in the sequence GANTC with high specificity. To investigate its mechanism of DNA recognition, we used the crystal structure of a related methyltransferase (M1.MboII, which modifies GAAGA) as a starting point, and docked into it a DNA substrate to identify the protein regions that approach the DNA. After alignment of CcrM and M1.MboII, we identified four candidate regions in CcrM to contain residues involved in DNA recognition. We mutated 20 amino acid residues within these regions, purified the CcrM variants, and determined their DNA-binding and catalytic activity on a cognate GANTC substrate and on nine near-cognate substrates, each of which contained a single base-pair substitution in the recognition sequence. Altogether, we identified four residues in two of the regions, mutations of which resulted in a strong (>100-fold) reduction of methylation activity. Our data show that DNA recognition by CcrM is a cooperative process, because disruption of critical contacts led to loss of catalytic activity but not to a relaxation in specificity. In addition, we identified a change in the readout of the fifth base pair in the GANTC sequence with two other CcrM variants that showed smaller reductions in overall activity. Based on this and the sequence alignment of CcrM with other DNA methyltransferases of same or related recognition sequence, we propose roles for these two regions in DNA recognition by CcrM.     

Scattering in a Spin-Charge Separated Non-Fermi Liquid

The electron self-energy due to the scattering on nonmagnetic impurities in a spin-charge separated non-Fermi liquid is calculated. The frequency dependence of the inverse scattering time is proportional to , for the case when the anomalous parameter = 0, and to ¹⁺ for 0. The scattering time is cutoff dependent when the anomalous parameter is nonzero.     

Information Foraging—A Model for Exploration Breadth and Depth

The optimal path choice theory from biology implies that foragers should evaluate all sites before selecting something feasible when site relocation costs are low and there are few sites to explore. In internet information foraging, although the cost of moving to another site is negligible, the number of relevant sites can be large and exploration costs vary. We examine human internet information foraging behaviors and propose a model relating them to established cognitive measures.     

Identification of traditional Thai colours used for mural paintings and Khon masks

Thai colour names used for mural paintings and Khon masks are not well known, uncommonly used, and some are forgotten. They are normally known today only among few artists who inherited the knowledge to paint them from their elders. However, the artists cannot quantitatively describe the characteristics of these colours, and this is a major impediment in colour identification and preservation studies that are necessary for future restoration works of temples and artifacts. The purpose of this article is to describe our research for identifying and quantitatively describing traditional Thai colours, as part of our effort to create a “Thai Colour Name Dictionary.” In this article, we show information about colour names which have never been mentioned in any international journal until now, and we describe the method we used to identify them with physical colours. The method is exemplified on 10 colour names. © 2011 Wiley Periodicals, Inc. Col Res Appl, 38, 229–234, 2013.     

Enzyme-mediated Synthesis of Silsesquioxanes

In an initial report we demonstrated that some serine proteases were suitable candidates for the hydrolysis and condensation of tetraethoxysilane and phenyltrimethoxysilane under solvent-free conditions. Using trypsin as a model enzyme, we have demonstrated the generality of this method by expanding the number of available silicon-based substrates that can be processed by the enzyme, as well as including pepsin to demonstrate that this phenomenon is not exclusive to a single family of enzymes. A series of time course ²⁹Si NMR experiments using D₂O revealed that the rate of hydrolysis of phenyltrimethoxysilane could be enhanced by a factor of 11–155 times over enzyme-free controls when either trypsin or pepsin were used as catalysts. The following trend was observed when comparing the hydrolysis/condensation rates of a number of different organotrimethoxysilanes: methyltrimethoxysilane>allytrimethoxysilane>ethyltrimethoxysilane>phenyltrimethoxysilane.     

New multifunctional textile biomaterials for the treatment of leg venous insufficiency

Acryloyl monomers have been synthesized by reaction of β-cyclodextrin and troxerutin with acryloyl chloride and grafted on a knitted material obtained from polyamide 6.6 and polyurethane fibers. Polyamide grafted with β-cyclodextrin derivative binds troxerutin as a physical complex. The obtained biomaterials have been tested in vivo on rats for their ability to deliver troxerutin (a flebotonic drug) to different skin areas (epidermis, dermis and vascular wall). The results showed that the new synthesized materials can act as multifunctional bioactive textiles that can display both compression (given by the textile material) and sustained venotonic and haemostatic properties (given by the troxerutin delivered from biomaterial to the skin).     

Non-audio–Video Gesture Recognition Systems

Wireless Personal Communications - Gesture recognition as a topic in computer science and language technology has the goal of interpreting human gestures via mathematical algorithms. Gestures can...