Spoofing with photograph or video is one of the most common manner to circumvent a face recognition system. In this paper, we present a real-time and non-intrusive method to address this based on individual images from a generic webcamera. The task is formulated as a binary classification problem, in which, however, the distribution of positive and negative are largely overlapping in the input space, and a suitable representation space is hence of importance. Using the Lambertian model, we propose two strategies to extract the essential information about different surface properties of a live human face or a photograph, in terms of latent samples. Based on these, we develop two new extensions to the sparse logistic regression model which allow quick and accurate spoof detection. Primary experiments on a large photo imposter database show that the proposed method gives preferable detection performance compared to others.

P2X receptor subunits have intracellular N and C termini, two membrane-spanning domains, and an extracellular loop of about 280 amino acids. We expressed the rat P2X 2 receptor in human embryonic kidney cells, and used alanine-scanning mutagenesis on 30 residues with polar side chains conserved among the seven rat P2X receptor subunits. This identified a region proximal to the first transmembrane domain which contained 2 lysine residues that were critical for the action of ATP (Lys 69 and Lys 71 ). We substituted cysteines in this region (Asp 57 to Asp 71 ) and found that for S65C and I67C ATPevoked currents were inhibited by methanethiosulfonates. At I67C, the inhibition by negatively charged ethylsulfonate and pentylsulfonate derivatives could be overcome by increasing the ATP concentration, consistent with a reduced affinity of ATP binding. The inhibitory action of the methanethiosulfonates was prevented by pre-exposure to ATP, suggesting occlusion of the binding site. Finally, introduction of negative charges into the receptor by mutagenesis at this position (I67E and I67D) also gave receptors in which the ATP concentration-response curve was right-shifted. The results suggest that residues close to Ile 67 contribute to the ATP-binding site.P2X receptors are ligand-gated ion channels in the plasma membrane (1). They are homomeric or heteromeric proteins, formed by assembly of subunits named P2X 1 -P2X 7 . Current evidence suggests that three subunits form a channel (or a multiple of three) (2, 3). The ligand for the P2X receptors is ATP, acting from the extracellular milieu. In this way ATP released from cells functions as a synaptic transmitter, an autocrine or paracrine signal, in a wide range of mammalian tissues (4). Other membrane proteins which bind ATP from the extracellular aspect include G-protein-coupled P2Y receptors, and degradative enzymes such as ectoATPase (4).The individual subunits of the P2X receptor seem unrelated in amino acid sequence to other ion channels, and indeed to other proteins. The proteins range in length from 379 to 595 amino acids. The P2X 2 receptor is normally glycosylated (Asn 183 , Asn 239 , and Asn 298 ), and experiments with the introduction of additional glycosylation sites by mutagenesis indicate that most of the protein is extracellular (the ectodomain: residues 50 -330) (5, 6). The N terminus and C terminus lie within the cell, and the residues 30 -50 and 330 -352 form membrane-spanning domains. Three kinds of approaches have been made to determine which parts of the molecule contribute to which of the functional properties of the channel, but none of these have addressed the ATP-binding site. First, the substituted cysteine accessibility method has been used to show that residues in and around the second membrane-spanning domain contribute to the formation of permeation pathway for cations (7,8); in particular, Thr 336 appears to lie in the outer vestibule of the pore and Asn 349 is internal to the gate of the pore (7). Second, desensitization is profound in the ca...

Breastfeeding is a complex process where the infant utilizes two forms of pressure during suckling, vacuum and compression. Infant applied compression, or positive oral pressure, to the breast has not been previously studied in vivo. The goal of this study is to use a methodology to capture the positive oral pressure values exerted by infants' maxilla (upper jaw) and mandible (lower jaw) on the breast areola during breastfeeding. In this study, the positive and negative (vacuum) pressure values are obtained simultaneously on six lactating mothers. Parallel to the pressure data measurements, ultrasound images are captured and processed to reveal the nipple deformations and the displacements of infants' tongues and jaw movements during breastfeeding. Motivated by the significant differences in composition between the tissue of the breast and the nipple–areola complex, the strain ratio values of the lactating nipples are obtained using these deformation measurements along with pre- and postfeed three-dimensional (3D) scans of the breast. The findings show an oscillatory positive pressure profile on the breast under both maxilla and mandible, which differs from clinical indications that only the mandible of an infant moves during breastfeeding. The strain ratio varies between mothers, which indicates volume changes in the nipple during feeding and suggests that previous assumptions regarding strain ratio for nonlactating breasts will not accurately apply to breast tissue during lactation.

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