The three-color and two-color Tantrix™ rotation puzzle problems are NP-complete via parsimonious reductions

Holzer and Holzer [M. Holzer, W. Holzer, Tantrix? rotation puzzles are intractable, Discrete Applied Mathematics 144(3) (2004) 345–358] proved that the Tantrix? rotation puzzle problem with four colors is NP-complete, and they showed that the infinite variant of this problem is undecidable. In this paper, we study the three-color and two-color Tantrix? rotation puzzle problems (3-TRP and 2-TRP) and their variants. Restricting the number of allowed colors to three (respectively, to two) reduces the set of available Tantrix? tiles from 56 to 14 (respectively, to 8). We prove that 3-TRP and 2-TRP are NP-complete, which answers a question raised by Holzer and Holzer [M. Holzer, W. Holzer, Tantrix? rotation puzzles are intractable, Discrete Applied Mathematics 144(3) (2004) 345–358] in the affirmative. Since our reductions are parsimonious, it follows that the problems Unique-3-TRP and Unique-2-TRP are DP-complete under randomized reductions. We also show that the another-solution problems associated with 4-TRP, 3-TRP, and 2-TRP are NP-complete. Finally, we prove that the infinite variants of 3-TRP and 2-TRP are undecidable.     

A comparison of the CPI, Franck, MMPI, and WAIS Masculinity-Femininity indexes.

Compared the WAIS Masculinity-Femininity (M-F) index with 3 other measures of masculinity-femininity: the Femininity scale of the CPI, the Masculinity-femininity score of the Franck Drawing Completion Test, and the Mf scale of the MMPI. All 4 measures differentiated significantly between the sexes of 60 undergraduate Ss. The WAIS M-F index did not correlate significantly with any of the other measures for either sex and should not be interpreted as a personality indicator of sexual inversion or homosexuality. It represents solely sex differences in certain aspects of intellectual performance. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Amperometric Bi-enzyme based biosensor for the detection of lactose—characterization and application

Based on the glucose oxidase-β-galactosidase sequence an enzyme probe for the specific determination of lactose has been developed. β-Galactosidases from different sources have been compared, the sensor containing β-galactosidase from Curvularia inaequalis has been characterized in respect of optimal pH, enzyme loading, apparent activity and functional stability. The response of the bi-enzyme probe depends linearly on lactose concentration between 0.02 and 3.00 mmol dm^?3. The application to different milk and foodstuff samples resulted in good correlations toward enzymatic photometric (y = (0.956x-1.67) mmol dm^?3) and infrared detection (y = (1.0772x-0.3909)%). Using a measuring frequency of 100 h^?1 the serial imprecision is about 2% for diluted milk, urine, or foodstuff samples.     

Some psychodynamic aspects of felt parental alliance in young children.

"No attempt is made to generalize this projective alliance beyond the possibility that it reflects some form of felt alliance on the part of the child. It is the relationship of this felt alliance to other factors that is presented here, as a research finding needing further, more direct, study for any real generalization." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Supported membrane nanodevices

Supported membrane nanodevices are based on natural or artificial ion channels embedded in a lipid membrane deposited on a chip wafer. Membrane conductance is modulated by biorecognitive events, with the use of intrinsic binding sites of the ion channel or via artificial sites fused to the channel protein. Artificial ion gates are constructed by coupling a specific ligand for the analyte near the channel entrance or a site important to triggering channel conformation. The binding event leads to the closure of the ion channel or induces a conformational change of the channel, reducing the ion flux. The signal transduced from the device is the decrease in the ion flux-induced electron current at a silver-silver chloride electrode at ultimate single-molecule sensitivity. Among the natural ion channels, gramicidin A, a transport antibiotic, was found to be most suitable, and thus was used by AMBRI, Australia, to set up prototypes of membrane biochips, using self-association of the dimer. Covalent dimerization-based devices, developed by the Vienna group, make use of the down-regulation of the permanently open membrane-spanning bisgramicidine ion channel. The reactive group at the C-terminus, a hydroxy group, allows precise coupling of the analyte-binding moiety in gramicidin as well as bisgramicidin. The device is set up with bilayer membranes deposited on apertures of a hydrophobic frame structure produced via microlithography, facing an aqueous or hydro-gel micro-environment on both sides, constructing black lipid membranes or patch-clamp devices "on chip." The setup of the device needs gel membrane supports that allow membrane formation and contribute to the stability of the bilayer by exposure of functional groups that promote electrostatic interaction and formation of hydrogen bridges and enable the introduction of covalent spacers and anchors. Photo-cross-linked polyvinylpyrrolidone and polyacrylamide, electropolymerized polydiaminobenzene and coated agarose, as well as various chemical modifications of these polymers, were employed as membrane supports. With optimized assemblies, the membrane support did allow the formation of stable bilayer membranes, proved by "gigaseal" (electrical sealing with giga-ohm resistance) to be free of any point defects in the lipid assembly. Supports with and without hydrophilic and hydrophobic anchors were studied with reference to promoting the formation of a self-assembled membrane, to their electric resistance, and to the capability to insert functional ionophores. All components, including novel chemically engineered ion channels, novel amphiphilic lipids, a microlithographically designed chip, isolating polymer frames, and a hydrogel membrane support, are combined in the new bionanodevice. Sensitivity and specificity were proved, for example, with the use of an antibody-antigen couple down-regulating the ion flux through the membrane channel. Single ion channels incorporated in the supported lipid bilayer gave stable signals at an operational stability of several hours, which is already sufficient to test and screen for membrane receptors but still insufficient to use this device as a sensor for off-site application. Further optimization to increase operational and storage stability is done by a number of groups to allow a broad application of these devices.     

A survey of document image classification: problem statement,classifier architecture and performance evaluation

Document image classification is an important step in Office Automation, Digital Libraries, and other document image analysis applications. There is great diversity in document image classifiers: they differ in the problems they solve, in the use of training data to construct class models, and in the choice of document features and classification algorithms. We survey this diverse literature using three components: the problem statement, the classifier architecture, and performance evaluation. This brings to light important issues in designing a document classifier, including the definition of document classes, the choice of document features and feature representation, and the choice of classification algorithm and learning mechanism. We emphasize techniques that classify single-page typeset document images without using OCR results. Developing a general, adaptable, high-performance classifier is challenging due to the great variety of documents, the diverse criteria used to define document classes, and the ambiguity that arises due to ill-defined or fuzzy document classes.     

An individual addressable and latchable actuator array for microfluidic systems

Microfluidic systems and applications are becoming more and more complex and therefore require a lot of individually addressable actuators and valves to guide the fluids inside the systems. In this paper, we present an actuator array based on a latchable phase change actuator, i.e. the solid/liquid phase change of the actuator medium is used to stabilize the two states of the actuator. The design of the actuator allows the individual control of a high number of actuators with only two external pressure lines. This is in contrast to conventional pressure-actuated membrane valves manufactured in soft elastomers such as PDMS (polydimethylsiloxane) which require increasing numbers of external pressure lines for a higher number of valves. First, we describe the general working principle of the actuator. The scalability of the actuator concept as well as the individual addressing is then demonstrated by means of two exemplary set-ups with four and twelve actuators. With the latter, we also show the suitability as a microvalve. We further characterized and optimized the response times of the actuator with respect to the heating power, the choice of the phase change medium as well as the volume of the actuator material used. We achieved switching times between the two stable states of the actuators in the range of 10 s.