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We perform first-principles electronic structure and spin-dependent transport calculations for a Fe/PbTiO3/Fe multiferroic tunnel junction with asymmetric TiO2- and PbO-terminated interfaces. We demonstrate that the interfacial electronic reconstruction driven by the in situ screening of ferroelectric polarization, in conjunction with the intricate complex band structure of barrier, play a decisive role in controlling the spin-dependent tunneling. Reversal of ferroelectric polarization results in a transition from insulating to half-metal-like conducting state for the interfacial Pb 6pz orbitals, which acts as an atomic-scale spin-valve by releasing the tunneling current in antiparallel magnetization configuration as the ferroelectric polarization pointing to the PbO-terminated interface. This effect produces large change in tunneling conductance. Our results open an attractive avenue in designing multiferroic tunnel junctions with excellent performance by exploiting the interfacial electronic reconstruction originated from the in situ screening of ferroelectric polarization. [ABSTRACT FROM AUTHOR]

The recently discovered hexagonal ABC-type hyperferroelectrics, in which the polarization persists in the presence of the depolarization filed, exhibit a variety of intriguing and potentially useful properties [Garrity et al., Phys. Rev. Lett. 112, 127601 (2014)]. For the existing prototype of LiBeSb, we present detailed first-principles calculations concerning the lattice dynamics, electronic structure, and optical properties. An unstable longitudinal optic mode in the high-symmetry structure and a large polarization of 0.5 C/m² in the polar phase are reported, including the remarkable dependence of Born effective charges on structural distortion. Using the HSE06 hybrid functional, we predict that LiBeSb has a small band-gap of 1.5 eV and shows dominant asymmetric covalent bonding character. Importantly, we find that there are remarkable absorptions in the whole visible spectrum. These features, combined with the enhanced carrier mobility, make LiBeSb as well as the whole family of hexagonal ABC-type hyperferroelectrics as promising candidates for ferroelectric photovoltaic materials with large bulk photovoltaic effect in the visible spectrum. [ABSTRACT FROM AUTHOR]

We report on first-principles calculations of a Ni monolayer inserted at one interface in the epitaxial Fe/PbTiO3/Fe multiferroic heterostructure, focusing on the magnetoelectric coupling and the spin-dependent transport properties. The results of magnetoelectric coupling calculations reveal an attractive approach to realize cumulative magnetoelectric effects in the ferromagnetic/ferroelectric/ferromagnetic superlattices. The underlying physics is attributed to the combinations of several different magnetoelectric coupling mechanisms such as interface bonding, spin-dependent screening, and different types of magnetic interactions. We also demonstrate that inserting a Ni monolayer at one interface in the Fe/PbTiO3/Fe multiferroic tunnel junction is an efficient method to produce considerable tunneling electroresistance effect by modifying the tunnel potential barrier and the interfacial electronic structure. Furthermore, coexistence of tunneling magnetoresistance and tunneling electroresistance leads to the emergence of four distinct resistance states, which can be served as a multistate-storage device. The complicated influencing factors including bulk properties of the ferromagnetic electrodes, decay rates of the evanescent states in the tunnel barrier, and the specific interfacial electronic structure provide us promising opportunities to design novel multiferroic tunnel junctions with excellent performances. [ABSTRACT FROM AUTHOR]

A model is presented that accounts for the observation of periodic lubricant ripples formed when a slider is flying on-track over a lubricated disk surface. It is shown that lubricant flow modulation from the air shear stress due to the low flying slider acting as a spring is responsible for the observed corrugation, as repeated flying over the same track enhances the effect. This is somewhat moderated by the relaxation of the lubricant perturbation, by surface diffusion. Depending on the relative magnitude of the shear and diffusion processes, the system can find itself into regions of stability where small perturbations decay away, or regions of instability where they increase exponentially. Instability is enhanced for lower fly height and higher disk rotational frequency, making it a challenge for future growth in disk drive performance and areal density. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

RNA labeling is crucial for the study of RNA structure and metabolism. Herein we report N6- allyladenosine (a6A) as a new small molecule for RNA labeling through both metabolic and enzyme-assisted manners. a6A behaves like A and can be metabolically incorporated into newly synthesized RNAs inside mammalian cells. We also show that human RNA N6- methyladenosine (m6A) methyltransferases METTL3/ METTL14 can work with a synthetic cofactor, namely allyl-SAM (S-adenosyl methionine with methyl replaced by allyl) in order to site-specifically install an allyl group to the N6-position of A within specific sequence to generate a6A-labeled RNAs. The iodination of N6-allyl group of a6A under mild buffer conditions spontaneously induces the formation of N¹,N6-cyclized adenosine and creates mutations at its opposite site during complementary DNA synthesis of reverse transcription. The existing m6A in RNA is inert to methyltransferase-assisted allyl labeling, which offers a chance to differentiate m6A from A at individual RNA sites. Our work demonstrates a new method for RNA labeling, which could find applications in developing sequencing methods for nascent RNAs and RNA modifications. [ABSTRACT FROM AUTHOR]

Transgenic plants that produce Bacillus thuringiensis (Bt) Cry toxins are cultivated worldwide to control insect pests. Resistance to Bt toxins threatens this technology and although, different resistance mechanisms have been identified, some have not been completely elucidated. To gain new insights into these mechanisms, we performed multiple back crossing from a 3000-fold Cry1Ac-resistant BtR strain from cotton bollworm (Helicoverpa armigera) isolating a 516-fold Cry1Ac-resistant strain (96CAD). Cry1Ac resistance in 96CAD was tightly linked to a mutant cadherin allele (mHaCad) that contained 35 amino acid substitutions compared with HaCad from a susceptible strain (96S). We observed significantly reduced levels of the mHaCad protein on the surface of the midgut epithelium in 96CAD as compared to 96S. Expression of both cadherin alleles from 96CAD and 96S in insect cells and immunofluorescence localization in insect midgut tissue sections showed that the HaCAD protein from 96S localizes on the cell membrane, whereas the mutant 96CAD-mHaCad was retained in the endoplasmic reticulum (ER). Mapping of the mutations identified a D172G substitution mainly responsible for cadherin mislocalization. Our finding of a mutation affecting membrane receptor trafficking represents an unusual and previously unrecognized Bt resistance mechanism. [ABSTRACT FROM AUTHOR]

Herein, we reported a multi-train focusing in viscoelastic flows where the fluid inertia effect is comparable with the elastic effect. Different from their behaviors in inertia- or elasticity-dominating flows, particles in the current elasto-inertial flow were found to equilibrate at two symmetrical positions in the vertical center plane under the balance of the shear-induced inertial lift force and the elastic force. With further increasing flow rate, a third focusing position was observed at the channel center due to the fast-increasing elastic force. Based on these findings, we experimentally explored the particle focusing behaviors over various influential factors to better understand the underlying mechanics. The sheathless and high-throughput focusing of particles into multiplex deterministic trains at the same plane provides a potential method for image-based particle/cell detection. [ABSTRACT FROM AUTHOR]

Acylated xylan-based magnetic Fe3O4 nanocomposite hydrogels (ACX-MNP-gels) were prepared by fabricating Fe3O4 nanoctahedra in situ within a hydrogel matrix which was synthesized by the copolymerization of acylated xylan (ACX) with acrylamide and N-isopropylacrylamide under ultraviolet irradiation. The size of the Fe3O4 fabricated within the hydrogel matrix could be adjusted through controlling the crosslinking concentrations (C). The magnetic hydrogels showed desirable magnetic and mechanical properties, which were confirmed by XRD, Raman spectroscopy, physical property measurement system, SEM, TGA, and compression test. Moreover, the catalytic performance of the magnetic hydrogels was explored. The magnetic hydrogels (C = 7.5 wt %) presented excellent catalytic activity and provided a sensitive response to H2O2 detection even at a concentration level of 5 x 10-6 mol⋅L-1. This approach to preparing magnetic hydrogels loaded with Fe3O4 nanoparticles endows xylan-based hydrogels with new promising applications in biotechnology and environmental chemistry. [ABSTRACT FROM AUTHOR]

Toobtain high-performance membranes for the separation of aromatic/aliphatichydrocarbons, AgCl nanoparticles were synthesized in a water-in-oilmicroemulsion using the ionic liquid 1-dodecyl-3-methyl imidazoiumchloride (C12mimCl) as surfactant and methyl methacrylate-styrene(MMA-St) mixture as oil phase. Then, AgCl/poly(MMA-co-St) hybrid membranes were prepared by microemulsion by in situ polymerization.UV–visible spectrophotometry and transmission electron microscopy(TEM) were used to explore the influence of the St-to-MMA ratio inthe oil phase on the morphology of AgCl nanoparticles in the microemulsion.The change in morphology of AgCl in membranes after polymerizationwas characterized by scanning electron microscopy and TEM. The separationperformance of different hybrid membranes was evaluated by swelling–sorptionexperiments and pervaporation experiments. Results showed that addinga low amount of St slightly influenced the size and distribution ofAgCl particles. Given the improvement in benzene separation, the performanceof hybrid membranes after adding St was higher than that of AgCl/PMMAmembranes. The maximum separation factor of hybrid membranes usingMMA and St as the oil phase reached about 27 and exceeded twice thatof AgCl/PMMA membranes. When the ratio of MMA and St was less than2, the strong π combination between St and AgCl caused a largeaggregation of AgCl particles both in the microemulsion and in themembranes, which evidently reduced the separation performance of themembranes. Increased AgNO3concentration led to the formationof more AgCl particles in the microemulsion, which enhanced the separationperformance of hybrid membranes. At high AgNO3concentration,more particles with short distances more easily aggregated, therebyobviously reducing the separation performance of the membranes. [ABSTRACT FROM AUTHOR]

Background: Proteins dynamically interact with each other to perform their biological functions. The dynamic operations of protein interaction networks (PPI) are also reflected in the dynamic formations of protein complexes. Existing protein complex detection algorithms usually overlook the inherent temporal nature of protein interactions within PPI networks. Systematically analyzing the temporal protein complexes can not only improve the accuracy of protein complex detection, but also strengthen our biological knowledge on the dynamic protein assembly processes for cellular organization. Results: In this study, we propose a novel computational method to predict temporal protein complexes. Particularly, we first construct a series of dynamic PPI networks by joint analysis of time-course gene expression data and protein interaction data. Then a Time Smooth Overlapping Complex Detection model (TS-OCD) has been proposed to detect temporal protein complexes from these dynamic PPI networks. TS-OCD can naturally capture the smoothness of networks between consecutive time points and detect overlapping protein complexes at each time point. Finally, a nonnegative matrix factorization based algorithm is introduced to merge those very similar temporal complexes across different time points. Conclusions: Extensive experimental results demonstrate the proposed method is very effective in detecting temporal protein complexes than the state-of-the-art complex detection techniques. [ABSTRACT FROM AUTHOR]

Background Identification of protein complexes can help us get a better understanding of cellular mechanism. With the increasing availability of large-scale protein-protein interaction (PPI) data, numerous computational approaches have been proposed to detect complexes from the PPI networks. However, most of the current approaches do not consider overlaps among complexes or functional annotation information of individual proteins. Therefore, they might not be able to reflect the biological reality faithfully or make full use of the available domain-specific knowledge. Results In this paper, we develop a Generative Model with Functional and Topological Properties (GMFTP) to describe the generative processes of the PPI network and the functional profile. The model provides a working mechanism for capturing the interaction structures and the functional patterns of proteins. By combining the functional and topological properties, we formulate the problem of identifying protein complexes as that of detecting a group of proteins which frequently interact with each other in the PPI network and have similar annotation patterns in the functional profile. Using the idea of link communities, our method naturally deals with overlaps among complexes. The benefits brought by the functional properties are demonstrated by real data analysis. The results evaluated using four criteria with respect to two gold standards show that GMFTP has a competitive performance over the state-of- the-art approaches. The effectiveness of detecting overlapping complexes is also demonstrated by analyzing the topological and functional features of multi- and mono-group proteins. Conclusions Based on the results obtained in this study, GMFTP presents to be a powerful approach for the identification of overlapping protein complexes using both the PPI network and the functional profile. The software can be downloaded from http://mail.sysu.edu.cn/home/stsddq@mail.sysu.edu.cn/dai/ others/GMFTP.zip. [ABSTRACT FROM AUTHOR]

Epithelial sodium channel (ENaC) in the kidneys is critical for Na+ balance, extracellular volume, and blood pressure. Altered ENaC function is associated with respiratory disorders, pseudohypoaldosteronism type 1, and Liddle syndrome. ENaC is known to interact with components of the cytoskeleton, but the functional roles remain largely unclear. Here, we examined the interaction between ENaC and filamins, important actin filament components. We first discovered by yeast two-hybrid screening that theC termini of ENaCα andβ subunits bind filamin A, B, and C, and we then confirmed the binding by in vitro biochemical assays. We demonstrated by co-immunoprecipitation that ENaC, either over-expressed in HEK, HeLa, and melanoma A7 cells or natively expressed in LLC-PK1 and IMCD cells, is in the same complex with native filamin. Furthermore, the biotinylation and co-immunoprecipitation combined assays showed the ENaC-filamin interaction on the cell surface. Using Xenopus oocyte expression and two-electrode voltage clamp electrophysiology, we found that co-expression of an ENaC-binding domain of filamin substantially reduces ENaC channel function. Western blot and immunohistochemistry experiments revealed that the filamin A Cterminus(FLNAC) modestly reduces the expression of the ENaCα subunit in oocytes and A7 cells. After normalizing the current by plasma membrane expression, we found that FLNAC results in ∼50%reduction in the ENaC channel activity. The inhibitory effect of FLNAC was confirmed by lipid bilayer electrophysiology experiments using purified ENaC and FLNAC proteins, which showed that FLNAC substantially reduces ENaC single channel open probability. Taken together, our study demonstrated that filamin reduces ENaC channel function through direct interaction on the cell surface. [ABSTRACT FROM AUTHOR]

Revealing functional units in protein-protein interaction (PPI) networks are important for understanding cellular functional organization. Current algorithms for identifying functional units mainly focus on cohesive protein complexes which have more internal interactions than external interactions. Most of these approaches do not handle overlaps among complexes since they usually allow a protein to belong to only one complex. Moreover, recent studies have shown that other noncohesive structural functional units beyond complexes also exist in PPI networks. Thus previous algorithms that just focus on non- overlapping cohesive complexes are not able to present the biological reality fully. Here, we develop a new regularized sparse random graph model (RSRGM) to explore overlapping and various structural functional units in PPI networks. RSRGM is principally dominated by two model parameters. One is used to define the functional units as groups of proteins that have similar patterns of connections to others, which allows RSRGM to detect non-cohesive structural functional units. The other one is used to represent the degree of proteins belonging to the units, which supports a protein belonging to more than one revealed unit. We also propose a regularizer to control the smoothness between the estimators of these two parameters. Experimental results on four S. cerevisiae PPI networks show that the performance of RSRGM on detecting cohesive complexes and overlapping complexes is superior to that of previous competing algorithms. Moreover, RSRGM has the ability to discover biological significant functional units besides complexes. [ABSTRACT FROM AUTHOR]

Filamins are important actin cross-linking proteins implicated in scaffolding, membrane stabilization and signal transduction, through interaction with ion channels, receptors and signaling proteins. Here we report the physical and functional interaction between filamins and polycystin-2, a TRP-type cation channel mutated in 10-15% patients with autosomal dominant polycystic kidney disease. Yeast two-hybrid and GST pull-down experiments demonstrated that the Ctermini of filamin isoforms A, B and C directly bind to both the intracellular N- and C-termini of polycystin-2. Reciprocal coimmunoprecipitation experiments showed that endogenous polycystin-2 and filamins are in the same complexes in renal epithelial cells and human melanoma A7 cells. We then examined the effect of filamin on polycystin-2 channel function by electrophysiology studies with a lipid bilayer reconstitution system and found that filamin-A substantially inhibits polycystin-2 channel activity. Our study indicates that filamins are important regulators of polycystin-2 channel function, and further links actin cytoskeletal dynamics to the regulation of this channel protein. [ABSTRACT FROM AUTHOR]

A similarity transformation connecting the variable coefficient nonlinear Schrödinger equation with the standard nonlinear Schrödinger equation is constructed. The self-similar rogue wave triplet solutions (rational solutions) are analytically obtained for the nonautonomous nonlinear and dispersive system. The controllable behaviours of rogue wave triplets in two typical soliton management systems are discussed. In the exponential dispersion decreasing fibre, three kinds of rogue wave triplets with controllable behaviours are analysed. In the periodic distributed system, the rogue wave triplets recur periodically in the form of a cluster. [ABSTRACT FROM AUTHOR]

A series of analytical nonautonomous soliton solutions for the (3+1)- dimensional nonlinear Schrödinger equation with variable coefficients in the presence of gain (loss) and a harmonic potential are obtained. The explicit functions which describe the evolution of the amplitude, phase and velocity are also given. Soliton's phase and velocity are independent of the gain parameter, and only the amplitude is affected by the gain parameter. The dynamical behaviors for nonautonomous chirp-free and chirped solitons in a periodic distributed and dispersion decreasing systems are discussed. By modulating appropriate diffraction/dispersion parameters, we can trap the velocity of each soliton to control the interaction between soliton pairs. The real and imaginary parts of the spectral parameters control the separating or interacting behavior of chirp-free soliton pairs. However, the appearance of the chirp restrains the interaction between the chirped soliton pairs. [ABSTRACT FROM AUTHOR]

We derive analytical rogue wave solutions of variable-coefficient higher-order nonlinear Schrôdinger equations describing the femtosecond pulse propagation via a transformation connected with the constant-coefficient Hirota equation. Then we discuss the propagation behaviors of controllable rogue waves, including recurrence, annihilation, and sustainment in a periodic distributed fiber system and an exponential dispersion decreasing fiber. Finally, we investigate nonlinear tunneling effects for rogue waves. [ABSTRACT FROM AUTHOR]

A ratiometric fluorescence sensor based on pyrene was designed for selective detection of heparin in HEPES (N-(2-hydroxyethyl)piperazine-N'-ethanesulfonic acid) buffer and serum sample. Pyrene and long-chain alkanes were linked through bisquaternary functionality in the sensor which could interact with heparin via supramolecular assembly. A ratiometric fluorescent signal change of the sensor can be observed because of the specific monomer-excimer conversion of pyrene which is modulated by the supramolecular self-assembly of sensor and heparin. Upon addition of heparin, the excimer emission of the sensor at 489 nm is observed and the monomer emission intensity at 395 nm decreases concomitantly. Addition of heparin derivatives with very similar structure such as chondroitin 4-sulfate or hyaluronic acid to the same sensor solution only leads to very smaller changes in intensity ratios probably because of lower charge density and more distant spatial distribution of anions (or disadvantageous spatial orientation of anions) as compared to those of heparin. The novel sensor can effectively differentiate heparin from its derivatives with relatively low background interference and wide linear response in HEPES and serum. A linear calibration curve is obtained from 0 to 3.4 μM for heparin quantification in serum. [ABSTRACT FROM AUTHOR]

To investigate the potential oxidation products of 5-hydroxymethylcytosine (5-hmC)-containing DNA, we present here efficient syntheses of 5-formyl- and 5-methoxycarbonyl-2′-deoxycytidine phosphoramidites. The 5-formyl group in IIIwas easy to introduce and was compatible with phosphoramidite and DNA syntheses. An additional treatment of ODN1 with NaBH4produced the corresponding ODN2 quantitatively. Phosphoramidite Vwas also incorporated into DNA, and the methyl ester could be hydrolyzed under mild basic conditions to afford ODN3. [ABSTRACT FROM AUTHOR]

5-Hydroxymethylcytosine (5-hmC) is a newly discovered DNA base modification in mammalian genomic DNA that is proposed to be a major epigenetic mark. We report here the syntheses of two new versions of phosphoramidites III and IV from 5-iodo-2′-deoxyuridine in 18% and 32% overall yields, respectively, with TBDMS as the 5-hydroxyl protecting group. Phosphoramidites III and IV allow efficient incorporation of 5-hmC into DNA and a "one-step" deprotection procedure to cleanly remove all the protecting groups. A "two-step" deprotection strategy is compatible with ultramild DNA synthesis, which enables the synthesis of 5hmC-containing DNA with additional modifications. [ABSTRACT FROM AUTHOR]

OBJECTIVE--The reversible attachment of small ubiquitin-like modifier (SUMO) proteins controls target localization and function. We examined an acute role for the SUMOylation pathway in downstream events mediating insulin secretion. RESEARCH DESIGN AND METHODS--We studied islets and f3-cells from mice and human donors, as well as INS-1 832/13 cells. Insulin secretion, intracellular Ca2+, and β-cell exocytosis were monitored after manipulation of the SUMOylation machinery. Granule localization was imaged by total internal reflection fluorescence and electron microscopy; immunoprecipitation and Western blotting were used to examine the soluble NSF attachment receptor (SNARE) complex formation and SUMO1 interaction with synaptotagmin VII. RESULTS--SUMO1 impairs glucose-stimulated insulin secretion by blunting the β-cell exocytotic response to Ca2+. The effect of SUMO1 to impair insulin secretion and β-cell exocytosis is rapid and does not require altered gene expression or insulin content, is downstream of granule docking at the plasma membrane, and is dependent on SUMO-conjugation because the deSUMOylating enzyme, sentrin/SUMO-specific protease (SENP)-1, rescues exocytosis. SUMO1 coimmunoprecipitates with the Ca2+ sensor synaptotagmin VII, and this is transiently lost upon glucose stimulation. SENP1 overexpression also disrupts the association of SUMO1 with synaptotagmin VII and mimics the effect of glucose to enhance exocytosis. Conversely, SENP1 knockdown impairs exocytosis at stimulatory glucose levels and blunts glucose-dependent insulin secretion from mouse and human islets. CONCLUSIONS--SUMOylation acutely regulates insulin secretion by the direct and reversible inhibition of β-cell exocytosis in response to intracellular Ca2+ elevation. The SUMO protease, SENP1, is required for glucose-dependent insulin secretion. [ABSTRACT FROM AUTHOR]

Three phenylenediamine isomers (including ortho-, meta- and para-derivatives) were electrochemically polymerized to give polyphenylenediamine (PPD) films on platinized glassy carbon electrodes. Amperometric glucose sensors were developed by immobilizing glucose oxidase (GOx) into these polymer matrices during polymerization. Effects of the polymerization potential, polymerization charge, monomer concentration, GOx concentration and Pt deposition charge on the performance of the enzyme electrode to glucose were investigated. These resulting GC/Pt/PPD-GOx electrodes showed rapid electrochemical responses to hydrogen peroxide and glucose, and very good anti-interference ability to ascorbic acid. Correlation between the electroanalytical behaviors of the enzyme electrodes and the polymer structures was examined. [ABSTRACT FROM AUTHOR]

Support vector regression and regularization networks are kernel-based techniques for solving the regression problem of recovering the unknown function from sample data. The choice of the kernel function, which determines the mapping between the input space and the feature space, is of crucial importance to such learning machines. Estimating the irregular function with a multiscale structure that comprises both the steep variations and the smooth variations is a hard problem. The result achieved by the traditional Gaussian kernel is often unsatisfactory, because it cannot simultaneously avoid underfitting and overfitting. In this paper, we present a new class of kernel functions derived from the framelet system. A framelet is a tight wavelet frame constructed via multiresolution analysis and has the merit of both wavelets and frames. The construction and approximation properties of framelets have been well studied. Our goal is to combine the power of framelet representation with the merit of kernel methods on learning from sparse data. The proposed framelet kernel has the ability to approximate functions with a multiscale structure and can reduce the influence of noise in data. Experiments on both simulated and real data illustrate the usefulness of the new kernels. [ABSTRACT FROM AUTHOR]

We present a variational approach to obtain high-resolution images from multiframe low-resolution video stills. The objective functional for the variational approach consists of a data fidelity term and a regularizer. The fidelity term is formed by adaptively mimicking l1 and l2 norms. The regularization uses the l1 norm of the framelet coefficients of a high-resolution image with a geometric tight framelet system constructed in this paper. The tight framelet system has abilities to detect multi-orientation and multi-order variations of an image. A two-phase iterative method for super-resolution reconstruction is proposed to construct a high-resolution image. The first phase is to get an approximation of the solution (i.e., the ideal image) using the steepest descent method. The second phase is to enhance the sparsity of the approximate solution by using the soft thresholding operator with variable thresholding parameters. Numerical results based on both synthetic data and real videos show that our algorithm is efficient in terms of removing visual artifacts and preserving edges in restored images. [ABSTRACT FROM AUTHOR]

We propose a novel facial representation based on the dual-tree complex wavelet transform for face recognition. It is effective and efficient to represent the geometrical structures in facial image with low redundancy. Moreover, we experimentally verify that the proposed method is more powerful to extract facial features robust against the variations of shift and illumination than the discrete wavelet transform and Gabor wavelet transform. [ABSTRACT FROM AUTHOR]

On face recognition, most previous works on dimensionality reduction and classification would first transform the input image into 1-D vector, which ignores the underlying data structure and often leads to the small sample size problem. More recently, 2-D discriminant analysis has become an interesting technique which can overcome the aforementioned drawbacks. However, 2-D methods extract features based on the rows or the columns of all images, so it is possible that the features using 2-D methods still contain some redundant information. In addition, most existing 2-D methods cannot provide an automatic strategy to choose discriminant vectors. In this paper, we study the combination of 2-D discriminant analysis and 1-D discriminant analysis and propose a two-stage framework: "(2D)2MMC + LDA." Because the extracted features based on maximal margin criterion (MMC) is robust, stable, and efficient, in the first stage, a 2-D two-directional feature extraction technique, (2D)2MMC, is presented. In the second stage, the linear discriminant analysis (LDA) step is performed in the (2D)2MMC subspace. Experiments with Feret, Olivetti and Oracle Research Laboratory, and Carnegie Mellon University Pose, Illumination, and Expression databases are conducted to evaluate our method in terms of classification accuracy and robustness. [ABSTRACT FROM AUTHOR]

With the help of Hermit transformation, it is firstly that the exp-fimction method is applied to solve nonlinear stochastic partial differential equations, and some new exact solutions of the stochastic mKdV equation in the white noise environment are obtained. It is shown that the exp-function method provides a straightforward and important mathematical tool for nonlinear stochastic partial differential equations in mathematical physics. [ABSTRACT FROM AUTHOR]

AppDNA is an intermediate in enzyme-catalyzed DNA ligation reactions, and its efficient enzymatic synthesis requires a donor-template duplex of at least 11 base pairs in length. An efficient chemical synthesis of AppDNA with the coupling of an adenosine 5′-phosphorimidazolidate to an immobilized DNA-5′-monophosphate as the key step is described. The adenylation efficiencies of DNA-5′-monophosphate were excellent for oligonucleotides containing less than 11 nucleotides and at least 50% for oligonucleotides containing 15−25 nucleotides. [ABSTRACT FROM AUTHOR]

We use branched circle packings to construct an approximating sequence to a proper quasiregular mapping, that is a general proper solution of a Beltrami equation. We show that the approximating sequence converges on compact subsets, and show that for given branch-set the solution is unique subject to a certain normalization. [ABSTRACT FROM AUTHOR]

High-dimensional data and the small sample size problem occur in many modern pattern classification applications such as face recognition and gene expression data analysis. To deal with such data, one important step is dimensionality reduction. Principal component analysis (PCA) and between-group analysis (BGA) are two commonly used methods, and various extensions of these two methods exist. The principle of these two approaches comes from their best approximation property. From a pattern recognition perspective, we show that PCA, which is based on the total scatter matrix, preserves linear separability, and BGA, which is based on between-class scatter matrix, retains the distance between class centroids. Moreover, we propose an automatic nonparameter uncorrelated discriminant analysis (UDA) algorithm based on the maximum margin criterion (MMC). The extracted features via UDA are statistically ,uncorrelated. UDA combines rank-preserving dimensionality reduction and constraint discriminant analysis and also serves as an effective solution for the small-sample-size problem. Experiments with face images and gene expression data sets are conducted to evaluate UDA in terms of classification accuracy and robustness. [ABSTRACT FROM AUTHOR]

Using symbolic and algebra computation, the extended tanh-function method (ETM) based on mapping method is further extended. The new variable separation solutions of the (2+1)-dimensional asymmetric Nizhnik-Novikov-Veselov (ANNV) system are derived. [ABSTRACT FROM AUTHOR]

Abstract   Background Transabdominal ultrasound cannot be used to quantitate fibrosis in patients with cirrhosis because of variability in the abdominal wall thickness and variability in the components of the abdominal wall (fat versus muscle). Endoscopic ultrasound through the gastric wall is always at a constant distance, approximately 3 mm, away from the liver when the transducer is just below the gastroesophageal junction, thereby eliminating this variability. Purpose To differentiate between cirrhotic and noncirrhotic liver using endoluminal ultrasound. Methods Eleven patients without known liver disease and eight patients with cirrhosis underwent endoscopic ultrasound using an Olympus linear ultrasound scope. The gain, contrast, frequency, and acoustic power were kept constant on the Aloka ultrasound processor. Videotaped images of the liver were recorded and then digitized on Image-Pro Plus software. The brightness of the image was adjusted to a standard brightness for each image and an area of interest was chosen using Photoshop 7.0. Vessels and artifacts were eliminated digitally and a histogram was produced using Photoshop to quantitate the pixel density for the area of interest from 0 (black) to 255 (white). Approximately 250,000 pixels were evaluated for each subject. The mean ± standard deviation (SD) pixel density of the noncirrhotic subjects was evaluated against the cirrhotic patients using a Student unpaired t-test. Results The mean echogenecity in patients with cirrhosis was 116.85 and the mean echogenecity in patients without cirrhosis was 92.75 (P P Conclusion A new method of evaluating the liver parenchyma (acoustic liver biopsy) that takes advantage of the proximity of the endoscopic ultrasound transducer to the liver and uses commercial image analysis technology that is inexpensive and widely available was developed. This is a preliminary study of this new technology, which demonstrates that endoscopic ultrasound, can be standardized in order to image, analyze, and compare the mean echogenecity and mean standard deviation of the pixel density in the liver in order to distinguish cirrhotic patients from patients without cirrhosis. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are major environmental carcinogens produced in the combustion of fossil fuels, tobacco, and other organic matter. Current evidence indicates that PAHs are transformed enzymatically to active metabolites that react with DNA to form adducts that result in mutations. Three activation pathways have been proposed: the diol epoxide path, the radical-cation path, and the quinone path. The latter involves aldo-keto reductase mediated oxidation of PAH dihydrodiol metabolites to catechols that enter into redox cycles with quinones. This results in generation of reactive oxygen species (ROS) that attack DNA, and the PAH quinones also react with DNA to form adducts. Several strategies for synthesis of the stable adducts formed by the o-quinone metabolites of carcinogenic PAHs with 2′- deoxyribonucleosides were investigated and compared. The PAH quinones studied were benz[alanthracene- 3,4-dione and its 7-methyl- and 7,12-dimethyl- derivatives. The parent PAHs represent a range of carcinogenicity from inactive to highly potent. Two synthetic methods were devised that differ in the catalyst employed, Pd(OAc)2 or Cul. The Pd-mediated method involved coupling a protected amino- catechol PAH derivative with a halo-2′-deoxyribonucleoside. The copper-mediated method entailed reaction of a halo-PAH catechol derivative with a 2′-deoxyribonucleoside. Adducts of benz[a]anthracene-3,4- dione (and its 7-methyl- and 7,12-dimethyl- derivatives) with 2′-deoxyadenosine and 2′-deoxyguanosine were prepared by these methods. Availability of adducts of these types through synthesis makes possible for the first time biological studies to determine the role of these adducts in tumorigenesis. The copper- mediated method offers advantages of economy, adaptability to large-scale preparation, utility for synthesis of 13C- or 15N-labeled analogues, and nonformation. of bis-adducts as secondary products. [ABSTRACT FROM AUTHOR]

Transient receptor potential (TRP) polycystin 2 and 3 (TRPP2 and 3) are homologous members of the TRP superfamily of cation channels but have different physiological functions. TRPP2 is part of a flow sensor, and is defective in autosomal dominant polycystic kidney disease and implicated in left–right asymmetry development. TRPP3 is reported to implicate in sour tasting in bipolar cells of taste buds of the tongue and in the regulation of pH-sensitive action potential in neurons surrounding the central canal of spinal cord. TRPP3 is present in both excitable and non-excitable cells in various tissues, such as retina, brain, heart, testis, and kidney, but its common and cell type-specific functional characteristics remain largely unknown. In this study, we investigated physical and functional interactions between TRPP3 and α-actinin, an actin-bundling protein known to regulate several types of ion channels. We employed planer lipid bilayer electrophysiology system to study the function of TRPP3 channel that was affinity-purified from Madin–Darby canine kidney cells. Upon reconstitution in bilayer, TRPP3 exhibited cation channel activities that were substantially augmented by α-actinin. The TRPP3-α-actinin association was documented by co-immunoprecipitation using native cells and tissues, yeast two-hybrid, and in vitro binding assays. Further, TRPP3 was abundantly present in mouse brain where it associates with α-actinin-2. Taken together, α-actinin not only attaches TRPP3 to the cytoskeleton but also up-regulates TRPP3 channel function. It remains to be determined whether the TRPP3-α-actinin interaction is relevant to acid sensing and other functions in neuronal and non-neuronal cells. [ABSTRACT FROM AUTHOR]

This paper reviews the present state of understanding of lubricant-slider interactions in a rigid disk drive. As slider flying heights are rapidly approaching the intrinsic limit of a disk topography (1-3 nm), it has become apparent that disk-slider clearance of less than a nanometer can be achieved, at least on a laboratory setup. We will discuss the implication of such low spacing on the lubricant film behavior, and provide general physical arguments that attempt to highlight lubricant attributes that are relevant under those clearance conditions. [ABSTRACT FROM AUTHOR]

This paper reviews the present state of understanding of lubricant-slider interactions in a rigid disk drive. As slider flying heights are rapidly approaching the intrinsic limit of a disk topography (1-3 nm), it has become apparent that disk-slider clearance of less than a nanometer can be achieved, at least on a laboratory setup. We will discuss the implication of such low spacing on the lubricant film behavior, and provide general physical arguments that attempt to highlight lubricant attributes that are relevant under those clearance conditions. [ABSTRACT FROM AUTHOR]

When the feature dimension is larger than the number of samples the small sample-size problem occurs. There is great. concern about it within the face recognition community. We point out that optimizing the Fisher index in linear discriminant analysis does not necessarily give the best performance for a face recognition system. We propose a new regularization scheme. The proposed method is evaluated using the Olivetti Research Laboratory database, the Yale database, and the Feret database. [ABSTRACT FROM AUTHOR]

2‘-Amino-2‘-deoxyguanosine and 3‘-amino-3‘-deoxyguanosine are valuable probes for investigating the metal ion interactions at the active site of the group I ribozyme. However, these experiments require a thorough understanding of the protonation state of the amino group at a specific pH. Here, we describe the first syntheses of 2‘-15N-amino-2‘-deoxyadenosine, 2‘-15N-amino-2‘-deoxyguanosine, and 3‘-15N-amino-3‘-deoxyguanosine. The 15N-enriched nucleus allows convenient and accurate determination of the amine pKaby 15N NMR. [ABSTRACT FROM AUTHOR]

The synthesis of the C8-aryl adducts of adenine and guanine formed by reaction of the radical cation metabolites of carcinogenic polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (BP) and dibenzo[def,p]chrysene (DBC), with DNA is reported. The synthetic approach involves in the key step direct reaction of a PAH aldehyde with a di- or triamine precursor of a purine. The method is operationally simple, affords good yields of adducts, and is broad in its scope. The C8-aryl adducts of adenine and guanine derived from BP (6-BP-8-Ade and 6-BP-8-Gua) and DBC (10-DBC-8-Ade and 10-DBC-8-Gua) were synthesized in good yields by this method. Analogous C8-aryl adenine and guanine derivatives of other PAHs (anthracene, benz[a]anthracene, and chrysene) were also readily prepared via this approach. This method of synthesis is superior to the only method that is currently available. It entails direct reaction of short-lived PAH radical cations (generated electrochemically or chemically) with 2′-deoxyribonucleosides or the corresponding purine bases. It provides the adducts in low yields accompanied by complex mixtures of secondary products. An alternative synthesis that involves Pd-catalyzed Suzuki-Miyaura coupling of arylboronic acids with 8-bromopurine nucleosides was also investigated. Although the C8-purine adducts of PAHs, such as naphthalene, phenanthrene, pyrene, and chrysene, could be prepared by this method, analogous adducts of carcinogenic PAHs and other structurally related PAHs, e.g., anthracene, benz[a]anthracene, benzo[ajpyrene, and dibenzo[def,p]chrysene, could not be obtained. This difference was shown to be a consequence of the facility of competing hydrolytic deboronation of the corresponding arylboronic acids. [ABSTRACT FROM AUTHOR]

Face recognition is a challenging problem due to variations in pose, illumination, and expression. Techniques that can provide effective feature representation with enhanced discriminability are crucial. Wavelets have played an important role in image processing for its ability to capture localized spatial-frequency information of images. In this paper, we propose a novel local discriminant coordinates method based on wavelet packet for face recognition to compensate for these variations. Traditional wavelet-based methods for face recognition select or operate on the most discriminant subband, and neglect the scattered characteristic of discriminant features. The proposed method selects the most discriminant coordinates uniformly from all spatial frequency subbands to overcome the deficiency of traditional wavelet-based methods. To measure the discriminability of coordinates, a new dilation invariant entropy and a maximum a posterior logistic model are put forward. Moreover, a new triangle square ratio criterion is used to improve classification using the Euclidean distance and the cosine criterion. Experimental results show that the proposed method is robust for face recognition under variations in illumination, pose and expression. [ABSTRACT FROM AUTHOR]

We consider an initial-boundary value problem for a one-dimensional parabolic equation with nonlocal boundary conditions. These nonlocal conditions are given in terms of integrals. Based on solution of the Dirichlet problem for the parabolic equation, we constructively establish the well-posedness for the nonlocal problem. [ABSTRACT FROM AUTHOR]

The Chinese herb Sparganum stoloniferum Buch.-Ham. (SBH) is frequently used to improve blood circulation and to rehabilitate vascular obstruction in traditional Chinese medicine. It was recently reported that SBH reduces the proliferation of renal epithelial cells stimulated by epidermal growth factor (EGF), and inhibits the phosphorylation of the EGF receptor. SBH has also been used as a trial drug to treat polycystic kidney disease (PKD) patients in China. The potential molecular actions of SBH on PKD remain unknown. Autosomal dominant PKD (ADPKD) is associated with mutations in polycystin-1 or polycystin-2 (PC2). PC2 and its homologue, polycystin-L (PCL), are nonselective cation channels permeable to potassium, sodium, and calcium. Here, we examine the effects of SBH on the human PCL channel expressed in Xenopus oocytes, using 2-microelectrode voltage-clamp electrophysiology and radiotracer uptake measurements. In PCL-expressing oocytes, with or without preincubation with SBH, the PCL channel was inhibited by SBH in a dose-dependent and reversible manner; a concentration of 2% SBH completely abolished the channel activation. The IC50 value for SBH was 0.48% 0.03%, with a 10-min preincubation period. SBH was also found to inhibit the PCL-mediated 45Ca tracer uptake in oocytes. Our study suggests that SBH contains 1 or more yet-to-be determined components that are inhibitors of PCL channel. The therapeutic potential of SBH for ADPKD and its chemical composition remain to be investigated. [ABSTRACT FROM AUTHOR]

In this paper, first, the ETM is applied to obtain variable separation solutions of (2+1)-dimensional systems. A common formula with some arbitrary functions is derived to describe suitable physical quantities for some (2+1)-dimensional models such as the generalized Nizhnik-Novikov-Veselov, Davey-Stewartson, Broer-Kaup-Kupershmidt, Boiti-Leon-Pempinelli, integrable Kortweg-de Vries (KdV), breaking soliton and Burgers models. The universal formula in Tang, Lou, and Zhang [Phys. Rev. E 66, 046601 (2002)] can be simplified to the common formula in the present paper, which indicates that redundant process is included there since the easier variable separation form can be employed without loss of generality. Second, this method is successfully generalized to (1+1)-dimensional systems, such as coupled integrable dispersionless, long-wave–short-wave resonance interaction and negative KdV models, and obtain another common formula to describe suitable physical fields or potentials of these (1+1)-dimensional models, which is similar to the one in (2+1)-dimensional systems. Moreover, it also is extended to (3+1)-dimensional Burgers system, and find that the common formula in (2+1)-dimensional systems is also appropriate to describe the (3+1)-dimensional Burgers system. The only differences are that the function q is a solution of a constraint equation and p is an arbitrary function of three independent variables. Finally, based on the common formula for (2+1)-dimensional systems and by selecting appropriate multivalued functions, interactions among special dromion, special peakon and foldon are investigated. The interactions between two special dromions, and between two special peakons, both possess novel properties, that is, there exist a multivalued foldon in the process of their collision, which is different from the reported cases in previous literature. Furthermore, the explicit phase shifts for all the local excitations offered by the common formula have been given, and are applied to these novel interactions in detail. [ABSTRACT FROM AUTHOR]

An extended mapping approach is used to obtain a new type of variable separation excitation, with three arbitrary functions, of the 2+1-dimensional generalized dispersive long wave equation (DLWE). By selecting appropriate functions, the richness of nonpropagating solitons, such as nonpropagating dromion, nonpropagating ring, nonpropagating lump, and nonpropagating foldon, etc., is displayed for the ($2+1$)-dimensional generalized dispersive long wave equation (DLWE) in this paper. Meanwhile, we conclude that the solution v1 and v2 are essentially equivalent to the “universal” formula. [ABSTRACT FROM AUTHOR]

Two boundary value problems are investigated for an over–determined elliptic system with several complex variables in polydisc. Necessary and sufficient conditions for the existence of finitely many linearly independent solutions and finitely many solvability conditions are derived. Moreover, the boundary value problem for any number of complex variables is treated in a unified way and the essential difference between the case of one complex variable and that of several complex variables is revealed. [ABSTRACT FROM AUTHOR]

We study the Riemann Hilbert Poincaré boundary value problem for analytic function. This problem will lead to inhomogeneous Fuchsian differential equations. We find that its spectrum is not characterized by the smoothness of its coefficient on the boundary but by its interior analytic continuation property. Moreover, the multiplicities of eigenfunctions for different eigenvalues are not necessarily the same even when the eigenvalues are small. [ABSTRACT FROM AUTHOR]

Below the critical micelle concentration (cmc) of Triton X-100, a PD-18C6 /Triton X-100 complex was found to exhibit an amplified fluorescence response for Pb 2 + in water. No such signal amplification was noted above the cmc. Dynamic light scattering and dark-field microscope analyses revealed that the PD-18C6 /Triton X-100 complex formed micron-size aggregates (1.24±0.39 μm) triggered by selective Pb 2 + binding, resulting in the enhancement of fluorescence intensity with a distinct blue shift of the fluorescence emission at pH 5.70. This is a novel supramolecular function of a PD-18C6 /Triton X-100 complex sensor for selective Pb 2 + recognition in water. [ABSTRACT FROM AUTHOR]

Efficient new syntheses of the o-quinone derivatives of benzo[a]pyrene (BPQ), 7,12-dimethylbenz[a] anthracene (DMBAQ), and benz[a]anthracene (BAQ), implicated as active carcinogenic metabolites of the parent polycyclic aromatic hydrocarbons (PAHs), are reported. These PAH quinones also serve as starting compounds for the synthesis of the other active metabolites of these PAHs thought to be involved in their mechanism(s) of carcinogenesis. The latter include the corresponding o-catechols, trans-dihydrodiols, and the corresponding anti- and syn-diol epoxides. [ABSTRACT FROM AUTHOR]

We consider the perturbed Schrödinger equation, which is an elliptic operator with unbounded coefficients. We use wavelets adapted to the Schrödinger operator to deal with problems on the unbounded domain. The wavelets are constructed from Hermite functions, which characterizes the space generated by the Schrödinger operator. We show that the Galerkin matrix can be pre-conditioned by a diagonal matrix so that its condition number is uniformly bounded. Moreover, we introduce a periodic pseudo-differential operator and show that its discrete Galerkin matrix under periodic wavelet system is equal to the Galerkin matrix for the equation with unbounded coefficients under the Hermite system. The convergence is proved in the L[sup 2] topology. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]