Investigation of the liquid crystal alignment layer: effect on electrical properties

We investigate the electrical behavior of a symmetric liquid crystal (LC) cell: elecrode-silane-LC-silane-electrode. The silane (chlorodimethyloctadecyl-silane) layer induces a homeotropic orientation of the nematic liquid crystal (NLC) molecules. The wettability technique is used to detect the change of the surface energy of the electrode upon cleaning and silane layer deposition. We report on the dynamic impedance measurements of the nematic liquid crystal cell. It is found that the silane alignment layer has a blocking effect on the liquid crystal (LC) cell. We also study the relaxation behavior of the cell which is later assimilated as an electrical equivalent circuit.     

Performances comparison between multilevel hierarchical and mesh FPGA interconnects

This paper evaluates a new multilevel hierarchical FPGA (MFPGA). The specific architecture includes two unidirectional programmable networks: a downward network based on the Butterfly-Fat-Tree topology; and a special upward network. New tools are developed to place and route several benchmark circuits on this architecture. Comparison with the traditional symmetric Manhattan mesh architecture shows that MFPGA can implement circuits with a smaller area and better speed.     

Exploration and optimization of a homogeneous tree-based application specific inflexible FPGA

An Application Specific Inflexible FPGA (ASIF) is a modified form of an FPGA which is designed for a predefined set of applications that operate at mutually exclusive times. An ASIF is a compromise between FPGAs and Application Specific Integrated Circuits (ASICs). Compared to an FPGA, an ASIF has reduced flexibility and improved density while compared to an ASIC, it has larger area but improved flexibility. This work presents a new homogeneous tree-based ASIF and uses a set of 16 MCNC benchmarks for experimentation. Experimental results show that, on average, a homogeneous tree-based ASIF gives 64% area gain when compared to an equivalent tree-based FPGA. Further, the experiments are performed to explore the effect of look-up table (LUT) and arity size on a tree-based ASIF. Later, comparison between tree and mesh-based ASIF is performed and results show that tree-based ASIF is 12% smaller in terms of routing area and consumes 77% less wires than mesh-based ASIF. Finally the quality comparison between two ASIFs reveals that, on average, tree-based ASIF gives 33% area gain as compared to mesh-based ASIF.     

Relation between Chemical Composition or Antioxidant Activity and Antihypertensive Activity for Six Essential Oils

Six essential oils (EOs), Juniperus phoenicea (leaves and berries), Thymus capitatus, Lauris nobilis, Melaleuca armillaris, and Eucalyptus gracilis, were screened for their antioxidant and antihypertensive activity as well as their chemical compositions. We identified and quantified 24 compounds (representing 99.8% of total oil) for J. phoenicea leaves, 14 compounds (representing 98.8% of total oil) for J. phoenicea berries, 11 compounds (representing 99.6% of total oil) for T. capitatus, 32 compounds (representing 98.9% of total oil) for L. nobilis, 32 compounds (representing 98.7% of total oil) for M. armillaris, and 26 compounds (representing 99.3% of total oil) for E. gracilis. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, the antioxidant activity was in the range of 0.59 to 2183.6 mg/L, whereas T. capitatus (1.24 ± 0.05 mg/L) gave the best activity in the 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonate assay. Antihypertensive activity was evaluated by testing the vasorelaxing capacity of EOs on rat aorta precontracted by phenylephrine (10(-6) M). T. capitatus and L. nobilis were most active for an antihypertensive activity (29 ± 3 and 59 ± 2 mg/L, respectively). Correlations between chemical composition or antioxidant activity and/or antihypertensive activity were studied. Significant correlation has been found for antihypertensive activity and p-cymene (R(2) = 0.86), β-elemene (R(2) = 0.90), and β-myrcene (R(2) = 0.76). A good correlation has been found between antihypertensive activity and antioxidant activity by DPPH assay (R(2) = 0.98). Antioxidant activity can contribute to the prevention of the increase of the blood pressure. According to the literature, no study has been reported until now of correlation between antihypertensive activity and antioxidant activity. Natural EOs can find its interest and application in a medicinal area.     

Chemical Composition and Antimicrobial and Antioxidant Activities of Essential Oils and Various Extracts of Juniperus phoenicea L. (Cupressacees)

ABSTRACT:  GC-FID and GC-MS analysis of essential oils of  Juniperus phoenicea  resulted in the identification of 30 compounds, representing more than 98% of the total composition. α-pinene (55.7% and 80.7%), δ-3-carene (10.7% and 4.5%), and γ-cadinene (2.9% and 5.1%) were the main components, respectively, in leaves and berries essential oil. Extracts of  J. phoenicea  were obtained by different extraction solvents: methanol, ethanol, ethyl acetate, and dichloromethane and evaluated composition for polyphenols (gallic acid equivalent 52 to 217 g/kg), tannins (catechin equivalent 6.5 to 60.2 g/kg), antocyanins (cyanidin equivalent 84 to 373 mg/kg), and flavonoids (quercetin equivalent 6.4 to 29.3 g/kg). The samples (essential oils and extracts) were subjected to a screening for their antioxidant activity by using DPPH and ABTS assays; antimicrobial activity was tested with 6 bacteria (3 Gram-positive and 3 Gram-negative), 1 yeast, and 2 fungi. The strongest antioxidant activity was obtained by the methanolic extract ( IC ₅₀= 6.5 ± 0.3 mg/L). Flavonoids are likely to contribute to the antifungal activity against  Saccharomyces cerevisiae.  Correlations were studied between chemical composition and antioxidant and antimicrobial activities.     

Comparison of photorefractive keratectomy with excimer laser in situ keratomileusis in correcting low myopia (from -2.00 to -5.50 diopters). A randomized study

OBJECTIVE: To compare laser in situ keratomileusis (LASIK) with photorefractive keratectomy (PRK) in the correction of myopia from -2.00 to -5.50 diopters. DESIGN: Prospective, randomized, paired clinical trial. PARTICIPANTS: Fifty-two eyes of 26 myopic patients were enrolled in the study. INTERVENTION: Each patient received PRK on one eye (PRK eye) and LASIK on the other (LASIK eye); the procedure assigned to each eye, and the sequence of surgeries for each patient was randomized. MAIN OUTCOME MEASURES: Slit-lamp microscopy, manifest refraction, uncorrected and spectacle-corrected visual acuity, and videokeratography were done before operation, and 2 weeks, 6 weeks, 3 months, 6 months, and 12 months after operation. Patient satisfaction and preference were assessed by a subjective questionnaire. RESULTS: All LASIK eyes had fast, painless recovery. At 1 year, 24 patients (92.3%) were examined, the mean spherical equivalent refraction was -0.08 +/- 0.38 diopter in the PRK eyes and -0.14 +/- 0.31 diopter in the LASIK eyes, and the uncorrected visual acuity was 20/20 or better in 15 PRK eyes (62.5%) and 19 LASIK eyes (79.2%); no eye lost 2 or more Snellen lines of spectacle-corrected visual acuity. Both procedures were stable throughout the first year. One PRK eye developed dense subepithelial corneal haze. The strongest correlate to spectacle-corrected visual acuity after the two procedures was the coefficient of variation of corneal power over the pupil. Nineteen patients (79.2%) preferred the LASIK procedure because of the fast, painless recovery. CONCLUSIONS: In the current study, PRK and LASIK were found to be similarly effective, predictable, stable, and reasonably safe for the correction of myopia between -2.00 and -5.50 diopters. Laser in situ keratomileusis has the advantage of fast, painless recovery. Patients prefer LASIK.     

Development of a rapid method based on front face fluorescence spectroscopy for the monitoring of egg freshness: 1—evolution of thick and thin egg albumens

In this preliminary study, the intrinsic fluorescence of thick and thin egg albumens was evaluated as a possible rapid method for the monitoring of egg freshness. The fluorescence emission spectra of tryptophan residues (excitation: 290 nm; emission: 305–430 nm) of proteins and fluorescent Maillard reaction products (excitation: 360; emission: 380–580 nm) were recorded directly on thick and thin albumen samples within 2–3, 4, 5, 9, 10, 12, 16, 18, 23, 25 and 29 days of storage. Principal component analysis (PCA) and factorial discriminant analysis (FDA) were applied to the spectra data sets. Considering tryptophan fluorescence spectra recorded on thick egg albumen, correct classification was observed for 62.8 and 54.3% for the calibration and the validation sets, respectively. Better classification was obtained from thin egg albumen since 67.3 and 69.1% of samples were correctly classified. Considering fluorescent Maillard reaction products, the similarity map determined by the principal components (PCs) 1 and 2 showed a discrimination of eggs as a function of their storage time on both thick and thin albumens. The percentage of samples correctly classified into four groups by the FDA was 97.4 and 91.4% for the calibration and validation thick albumen samples, respectively. It was concluded that fluorescent Maillard reaction products could be considered as fingerprints that may allow the discrimination between fresh and aged eggs.     

Hybrid Deep Neural Network-Based Text Representation Model to Improve Microblog Retrieval

Abstract

Retrieving relevant information from Twitter is always a challenging task given its vocabulary mismatch, sheer volume and noise. Representing the content of text tweets is a critical part of any microblog retrieval model. For this reason, deep neural networks can be used for learning good representations of text data and then conduct to a better matching. In this paper, we are interested in improving both representation and retrieval effectiveness in microblogs. For that, a Hybrid-Deep Neural-Network-based text representation model is proposed to extract effective features’ representations for clustering oriented microblog retrieval. HDNN combines recurrent neural network and feedforward neural network architectures. Specifically, using a bi-directional LSTM, we first generate a deep contextualized word representation which incorporates character n-grams form FasText. However, these contextual embedded existing in a high-dimensional space are not all important. Some of them are redundant, correlated and sometimes noisy making the learning models over-fitting, complex and less interpretable. To deal with these problems, we proposed a Hybrid-Regularized-Autoencoder-based method which combines autoencoder with Elastic Net regularization for an effective unsupervised feature selection and extraction. Our experimental results show that the performance of clustering and especially information retrieval in microblogs depend heavily on features’ representation.     

Adaptive terminal sliding mode control for rigid robotic manipulators

In order to apply the terminal sliding mode control to robot manipulators, prior knowledge of the exact upper bound of parameter uncertainties, and external disturbances is necessary. However, this bound will not be easily determined because of the complexity and unpredictability of the structure of uncertainties in the dynamics of the robot. To resolve this problem in robot control, we propose a new robust adaptive terminal sliding mode control for tracking problems in robotic manipulators. By applying this adaptive controller, prior knowledge is not required because the controller is able to estimate the upper bound of uncertainties and disturbances. Also, the proposed controller can eliminate the chattering effect without losing the robustness property. The stability of the control algorithm can be easily verified by using Lyapunov theory. The proposed controller is tested in simulation on a two-degree-of-freedom robot to prove its effectiveness.