Convolutional Neural Network Approach for Multispectral Facial Presentation Attack Detection in Automated Border Control Systems

Automated border control systems are the first critical infrastructure point when crossing a border country. Crossing border lines for unauthorized passengers is a high security risk to any country. This paper presents a multispectral analysis of presentation attack detection for facial biometrics using the learned features from a convolutional neural network. Three sensors are considered to design and develop a new database that is composed of visible (VIS), near-infrared (NIR), and thermal images. Most studies are based on laboratory or ideal conditions-controlled environments. However, in a real scenario, a subject’s situation is completely modified due to diverse physiological conditions, such as stress, temperature changes, sweating, and increased blood pressure. For this reason, the added value of this study is that this database was acquired in situ. The attacks considered were printed, masked, and displayed images. In addition, five classifiers were used to detect the presentation attack. Note that thermal sensors provide better performance than other solutions. The results present better outputs when all sensors are used together, regardless of whether classifier or feature-level fusion is considered. Finally, classifiers such as KNN or SVM show high performance and low computational level.     

Length of magnetic field lines in turbulent plasmas

An estimation of the length of any magnetic field line in a two-dimensional periodic magnetohydrodynamic problem is provided. This is done by using some classical function theory results on the analytic extension of the vector potential. The essential parameter, the maximum of this extension, may be analyzed in the case of turbulent plasmas by admitting the Iroshnikov-Kraichnan statistics, establishing in this way a relation between the length of any magnetic field line and the energy dissipation scale. (c) 2002 American Institute of Physics.     

Inhibition studies on salicylate synthase

Analogues of chorismate and isochorismate were designed and tested as potential inhibitors in the first inhibition study against a salicylate synthase.     

FeCl3-catalyzed addition of nitrogen and 1,3-dicarbonyl nucleophiles to olefins

A direct intermolecular addition of nitrogen and 1,3-dicarbonyl nucleophiles to stabilized double bonds (styrenes, 1,3-dienes, enol-ethers, sugars.) in the presence of green and inexpensive FeCl₃ catalyst is described.     

Effectiveness of Photodynamic Therapy in Elimination of HPV‐16 and HPV‐18 Associated with CIN I in Mexican Women

This study aimed to determine the effectiveness of photodynamic therapy (PDT), using δ‐aminolevulinic acid (5‐ALA), in the elimination of premalignant cervical lesions in Mexican patients with human papillomavirus (HPV) infection and/or cervical intraepithelial neoplasia (CIN). Thirty women diagnosed with CIN I and/or positive for HPV participated in the study. Topical 6% 5‐ALA in gel form was applied to the uterine cervix; after 4 h, the lesion area was irradiated with a light dose of 200 J cm^?2 at 635 nm. This procedure was performed three times at 48‐h intervals. Clinical follow‐up was performed at 3, 6, and 12 months after the initial PDT administration, by colposcopy, cervical cytology, histopathological analysis, polymerase chain reaction, and hybrid capture. Of HPV‐infected patients without evidence of CIN I, 80% cleared the infection, while HPV associated with CIN I was eliminated in 83% of patients (P < 0.05). At 12 months, CIN I had regressed in 57% of patients, although this response was not statistically significant. PDT using 6% 5‐ALA is concluded to be effective in eliminating HPV infection associated or not with CIN I.     

The influence of crystal formation on segmental mobility in polymers: hints from a statistical mechanical relaxation model

A statistical mechanical model is used to analyze literature data regarding the restricted segmental dynamics of a number of crystallized polymers, as observed by means of broadband dielectric spectroscopy. A relationship between well defined physical quantities and the width parameter in the Havriliak–Negami representation of symmetric processes is established. It is found that, for materials crystallized from an isotropic amorphous state, the segmental relaxation process is associated to conformational changes within cooperatively rearranging regions of ~1 nm diameter. In case of chain orientation, the dimension of the rearranging regions along the chain direction increases up to 3–5 nm. It is argued that the average size of the rearranging regions may influence the thickness of the amorphous interlamellar layers in the stacks. It is also found in all cases that, at the end of the crystallization process, the average fluctuation component of the chemical potential within the confined amorphous regions, $\overline{\Delta\mu}A statistical mechanical model is used to analyze literature data regarding the restricted segmental dynamics of a number of crystallized polymers, as observed by means of broadband dielectric spectroscopy. A relationship between well defined physical quantities and the width parameter in the Havriliak–Negami representation of symmetric processes is established. It is found that, for materials crystallized from an isotropic amorphous state, the segmental relaxation process is associated to conformational changes within cooperatively rearranging regions of ~1 nm diameter. In case of chain orientation, the dimension of the rearranging regions along the chain direction increases up to 3–5 nm. It is argued that the average size of the rearranging regions may influence the thickness of the amorphous interlamellar layers in the stacks. It is also found in all cases that, at the end of the crystallization process, the average fluctuation component of the chemical potential within the confined amorphous regions, [`(Dm)]\overline{\Delta\mu}, is of the same order of the chemical potential drop Δμ <sub>cryst</sub> associated to crystallization from the undercooled, relaxed melt. Except in one among the cases considered, it is found that [`(Dm)] ? - Dm_cryst\overline{\Delta\mu}\approx - \Delta\mu_{\rm cryst}, which is a hint towards the formalization of a thermodynamic criterion for crystallization arrest.     

Bioinspired terpene synthesis: a radical approach

This tutorial review highlights the development of radical-based bioinspired synthesis of terpenes from the initial proposal to the development of modern catalytic methods for performing such processes. The power of the radical approach is demonstrated by the straightforward syntheses of many natural products from readily available starting materials. The efficiency of these processes nicely complements the described cationic polyolefin cyclisations and even suggests that modern radical methods provide means to improve upon nature's synthetic pathways.     

Adsorption of arsenic (V) from a water solution onto a surfactant-modified zeolite

In this study a surfactant-modified zeolite (SMZ) was prepared by adsorbing the cationic surfactant hexadecyltrimethylammonium (HDTMA) bromide on a clinoptilolite. The adsorption of the surfactant modified the surface properties of the clinoptilolite and enhanced the anionic capacity of the SMZ. The adsorption equilibrium data of As(V) from the water solution on the SMZ were obtained in a batch adsorber, and the Langmuir isotherm matched the data reasonably well. The As(V) adsorption capacity of the SMZ was 12.5 times greater than that of the clinoptilolite. The adsorption of As(V) on SMZ was mainly due to the interactions between the anionic sites of the SMZ and the As(V) anions in water solution. The adsorption capacity of the SMZ was dependent on the solution pH. The adsorption capacity was increased and decreased by augmenting the pH from 5 to 7 and from 7 to 12, respectively. This unusual behavior was due to the fact that the affinity of the As(V) for the SMZ was dependent on the As(V) species that were present in solution. The adsorption capacity of the SMZ was slightly favored by decreasing the temperature from 25 to 15 °C. The heat of adsorption was estimated to be ΔH _ads=−46.82 KJ/mol, indicating that the adsorption was exothermic and the As(V) was chemisorbed on the SMZ.     

A disposable electrochemical immunosensor for prolactin involving affinity reaction on streptavidin-functionalized magnetic particles

A novel electrochemical immunosensor was developed for the determination of the hormone prolactin. The design involved the use of screen-printed carbon electrodes and streptavidin-functionalized magnetic particles. Biotinylated anti-prolactin antibodies were immobilized onto the functionalized magnetic particles and a sandwich-type immunoassay involving prolactin and anti-prolactin antibody labelled with alkaline phosphatase was employed. The resulting bio-conjugate was trapped on the surface of the screen-printed electrode with a small magnet and prolactin quantification was accomplished by differential pulse voltammetry of 1-naphtol formed in the enzyme reaction using 1-naphtyl phosphate as alkaline phosphatase substrate. All variables involved in the preparation of the immunosensor and in the electrochemical detection step were optimized. The calibration plot for prolactin exhibited a linear range between 10 and 2000 ng mL(-1) with a slope value of 7.0 nA mL ng(-1). The limit of detection was 3.74 ng mL(-1). Furthermore, the modified magnetic beads-antiprolactin conjugates showed an excellent stability. The immunosensor exhibited also a high selectivity with respect to other hormones. The analytical usefulness of the immnunosensor was demonstrated by analyzing human sera spiked with prolactin at three different concentration levels.