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Xianglian Song, Zizhuo Liu, Yuanjiang Xiang, Koray Aydin
Most of hyperbolic metamaterials (HMMs) investigated to date are based on isotropic materials resulting in uniaxial HMMs in which dielectric permittivities perpendicular to the propagation direction are the same. Using an anisotropic material constituent to form a HMM is a promising research direction providing opportunities to control the dielectric permittivity in all three directions independently. Herein, we propose and theoretically demonstrate novel biaxial HMMs composed of multilayer stacks of few-layer black phosphorus (BP) and Au thin films...
March 5, 2018: Optics Express
Neethu Mariam Joy, S Umesh
Assistive speech-based technologies can improve the quality of life for people affected with dysarthria, a motor speech disorder. In this paper, we explore multiple ways to improve Gaussian mixture model and deep neural network (DNN) based hidden Markov model (HMM) automatic speech recognition systems for TORGO dysarthric speech database. This work shows significant improvements over the previous attempts in building such systems in TORGO. We trained speaker-specific acoustic models by tuning various acoustic model parameters, using speaker normalized cepstral features and building complex DNN-HMM models with dropout and sequence-discrimination strategies...
March 2018: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Dylan Lu, Haoliang Qian, Kangwei Wang, Hao Shen, Feifei Wei, Yunfeng Jiang, Eric E Fullerton, Paul K L Yu, Zhaowei Liu
Semiconductor quantum well (QW) light-emitting diodes (LEDs) have limited temporal modulation bandwidth of a few hundred MHz due to the long carrier recombination lifetime. Material doping and structure engineering typically leads to incremental change in the carrier recombination rate, whereas the plasmonic-based Purcell effect enables dramatic improvement for modulation frequency beyond the GHz limit. By stacking Ag-Si multilayers, the resulting hyperbolic metamaterials (HMMs) have shown tunability in the plasmonic density of states for enhancing light emission at various wavelengths...
March 7, 2018: Advanced Materials
Surendra Neupane, Qin Ma, Febina M Mathew, Adam J Varenhorst, Ethan J Andersen, Madhav P Nepal
Disease-resistant genes (R genes) encode proteins that are involved in protecting plants from their pathogens and pests. Availability of complete genome sequences from soybean and common bean allowed us to perform a genome-wide identification and analysis of the Toll interleukin-1 receptor-like nucleotide-binding site leucine-rich repeat (TNL) proteins. Hidden Markov model (HMM) profiling of all protein sequences resulted in the identification of 117 and 77 regular TNL genes in soybean and common bean, respectively...
March 2, 2018: Biochemical Genetics
Youngjoo Suh, Hoirin Kim
The histogram equalization approach is an efficient feature normalization technique for noise robust automatic speech recognition. However, it suffers from performance degradation when some fundamental conditions are not satisfied in the test environment. To remedy these limitations of the original histogram equalization methods, class-based histogram equalization approach has been proposed. Although this approach showed substantial performance improvement under noise environments, it still suffers from performance degradation due to the overfitting problem when test data are insufficient...
February 2018: Journal of the Acoustical Society of America
James S Steele, Keith Bush, Zachary N Stowe, George A James, Sonet Smitherman, Clint D Kilts, Josh Cisler
Numerous data demonstrate that distracting emotional stimuli cause behavioral slowing (i.e. emotional conflict) and that behavior dynamically adapts to such distractors. However, the cognitive and neural mechanisms that mediate these behavioral findings are poorly understood. Several theoretical models have been developed that attempt to explain these phenomena, but these models have not been directly tested on human behavior nor compared. A potential tool to overcome this limitation is Hidden Markov Modeling (HMM), which is a computational approach to modeling indirectly observed systems...
2018: PloS One
Yufei Shen, Yixin Yan, Alyssa N Brigeman, Hoyeon Kim, Noel C Giebink
Upper-excited state emission is not usually observed from molecules owing to competition with much faster non-radiative relaxation pathways; however, it can be made more efficient by modifying the photonic density of states to enhance the radiative decay rate. Here, we show that embedding the small molecule zinc tetraphenylporphyrin (ZnTPP) in a hyperbolic metamaterial enables an ~18-fold increase in fluorescence intensity from the second singlet excited state (S2 ) relative to that from the lowest singlet excited state (S1 )...
February 22, 2018: Nano Letters
Song-Can Chen, Gui-Lan Duan, Kai Ding, Fu-Yi Huang, Yong-Guan Zhu
Identifying functional microorganisms involved in the degradation of high-molecular-mass polycyclic aromatic hydrocarbons (HMM-PAHs) in agricultural soil environments could assist in developing bioremediation strategies for soil PAH-contamination. Active populations of HMM-PAHs degraders in agricultural soils are currently poorly understood. In this study, we identified aerobic pyrene-degrading bacteria in agricultural and industrial soils by 13C-pyrene incubations followed by DNA stable isotope probing (DNA-SIP) and high-throughput sequencing...
February 15, 2018: FEMS Microbiology Ecology
Markus Götz, Philipp Wortmann, Sonja Schmid, Thorsten Hugel
Single-molecule Förster resonance energy transfer (smFRET) has become a widely used biophysical technique to study the dynamics of biomolecules. For many molecular machines in a cell proteins have to act together with interaction partners in a functional cycle to fulfill their task. The extension of two-color to multi-color smFRET makes it possible to simultaneously probe more than one interaction or conformational change. This not only adds a new dimension to smFRET experiments but it also offers the unique possibility to directly study the sequence of events and to detect correlated interactions when using an immobilized sample and a total internal reflection fluorescence microscope (TIRFM)...
January 30, 2018: Journal of Visualized Experiments: JoVE
Lu Wang, Shilong Li, Biran Zhang, Yuzhou Qin, Ziao Tian, Yangfu Fang, Yonglei Li, Zhaowei Liu, Yongfeng Mei
We demonstrate hyperbolic metamaterials (HMMs) on curved surface for an efficient outcoupling of non-radiative modes, which lead to an enhanced spontaneous emission. Those high-wavevector plasmonic modes can propagate along the curved structure and emit into the far-field, realizing a directional light emission with maximal fluorescent intensity. Detailed simulations disclose a high Purcell factor and a spatial power distribution in the curved HMM, which agrees with the experimental result. Our work presents remarkable enhancing capability in both Purcell factor and emission intensity, which could suggest unique structure design in metamaterials for potential application in e...
February 13, 2018: ACS Applied Materials & Interfaces
Lílian L Lopes, Daniela Mayumi U P Rocha, Alessandra da Silva, Maria do Carmo G Peluzio, Josefina Bressan, Helen Hermana M Hermsdorff
PURPOSE: We evaluated postprandial response of the lipid metabolism markers after the intake of a high-saturated fat (HSM) or high-monounsaturated fat meal (HMM). METHODS: A randomized, controlled and acute intervention study included 63 women (age 26.9 ± 6.1 years): 35 normal weight (NW) and 28 overweight (OW) (total body fat [TBF] 24.7 ± 3.9% and 36.6 ± 3.9%, respectively). After 12 hours of fasting, each subject was given one of the two test meals standardized, including 2 muffins and water (HSM, 42...
February 9, 2018: Journal of the American College of Nutrition
Fuming Fang, Takahiro Shinozaki
Human-computer interface systems whose input is based on eye movements can serve as a means of communication for patients with locked-in syndrome. Eye-writing is one such system; users can input characters by moving their eyes to follow the lines of the strokes corresponding to characters. Although this input method makes it easy for patients to get started because of their familiarity with handwriting, existing eye-writing systems suffer from slow input rates because they require a pause between input characters to simplify the automatic recognition process...
2018: PloS One
Mariam Lami, Harsimrat Singh, James H Dilley, Hajra Ashraf, Matthew Edmondon, Felipe Orihuela-Espina, Jonathan Hoare, Ara Darzi, Mikael H Sodergren
BACKGROUND:  The adenoma detection rate (ADR) is an important quality indicator in colonoscopy. The aim of this study was to evaluate the changes in visual gaze patterns (VGPs) with increasing polyp detection rate (PDR), a surrogate marker of ADR. METHODS:  18 endoscopists participated in the study. VGPs were measured using eye-tracking technology during the withdrawal phase of colonoscopy. VGPs were characterized using two analyses - screen and anatomy. Eye-tracking parameters were used to characterize performance, which was further substantiated using hidden Markov model (HMM) analysis...
February 7, 2018: Endoscopy
Xiaole Yin, Xiao-Tao Jiang, Benli Chai, Liguan Li, Ying Yang, James R Cole, James M Tiedje, Tong Zhang
Motivation: Much global attention has been paid to antibiotic resistance in monitoring its emergence, accumulation and dissemination. For rapid characterization and quantification of antibiotic resistance genes (ARGs) in metagenomic datasets, an online analysis pipeline, ARGs-OAP has been developed consisting of a database termed Structured Antibiotic Resistance Genes (the SARG) with a hierarchical structure (ARGs type-subtype-reference sequence). Results: The new release of the database, termed SARG version 2...
February 2, 2018: Bioinformatics
Zhiwei Guo, Haitao Jiang, Yunhui Li, Hong Chen, G S Agarwal
Near-field coupling is a fundamental physical effect, which plays an important role in the establishment of classical analog of electromagnetically induced transparency (EIT). However, in a normal environment the coupling length between the bright and dark artificial atoms is very short and far less than one wavelength, owing to the exponentially decaying property of near fields. In this work, we report the realization of a long range EIT, by using a hyperbolic metamaterial (HMM) which can convert the near fields into high-k propagating waves to overcome the problem of weak coupling at long distance...
January 22, 2018: Optics Express
Mai Higuchi, Junichi Takahara
Hyperbolic metamaterials (HMMs) show great promise in photonics applications because their unconventional open isofrequency surface permits enlargement of wavenumbers without limitation. Although optical behaviors in HMMs can be macroscopically described by theoretical calculations with the effective medium approximation (EMA), neglect of microscopic phenomena in each layer leads to discrepancies from exact numerical results. We clarify the origin of bulk propagating waves in HMMs and we show that they can be classified into two modes: long- and short-range surface-plasmon-based coupled modes (LRSP and SRSP, respectively)...
January 22, 2018: Optics Express
Mai Desouky, Ahmed M Mahmoud, Mohamed A Swillam
Perfect absorbers are indispensable components for energy harvesting applications. While many absorbers have been proposed, they encounter inevitable drawbacks including bulkiness or instability over time. The urge for CMOS compatible absorber that can be integrated for on chip applications requires further investigation. We theoretically demonstrate Silicon (Si) based mid IR super absorber with absorption (A) reaching 0.948. Our structure is composed of multilayered N-doped Si/ Si hyperbolic metamaterial (HMM) integrated with sub-hole Si grating...
February 1, 2018: Scientific Reports
Kirubin Pillay, Anneleen Dereymaeker, Katrien Jansen, Gunnar Naulaers, Sabine Van Huffel, Maarten De Vos
<i>Objective</i>. We develop a method for automated four-state sleep classification of preterm and term-born babies at term-age of 38-40 weeks postmenstrual age (the age since the last menstrual cycle of the mother) using multichannel Electroencephalogram (EEG) recordings. At this critical age, EEG differentiates from broader Quiet Sleep (QS) and Active Sleep (AS) stages to four, more complex states, and the quality and timing of this differentiation is indicative of the level of brain development...
January 30, 2018: Journal of Neural Engineering
David Aaron Moses, Matthew Leonard, Edward F Chang
OBJECTIVE: Recent research has characterized the anatomical and functional basis of speech perception in the human auditory cortex. These advances have made it possible to decode speech information from activity in brain regions like the superior temporal gyrus, but no published work has demonstrated this ability in real-time, which is necessary for neuroprosthetic brain-computer interfaces. APPROACH: Here, we introduce a real-time Neural Speech Recognition (rtNSR) software package, which was used to classify spoken input from high-resolution electrocorticography signals in real-time...
January 30, 2018: Journal of Neural Engineering
Kwang Jin Lee, Yeon Ui Lee, Frédéric Fages, Jean-Charles Ribierre, Jeong Weon Wu, Anthony D'Aléo
Metallic nanostructures permit controlling various photophysical processes by coupling photons with plasmonic oscillation of electrons confined in the tailored nanostructures. One example is hyperbolic metamaterial (HMM) leading to an enhanced spontaneous emission rate of emitters located nearby. Noting that emission in organic molecules is from either π-π* or intramolecular charge-transfer (ICT) states, we address here how HMM modifies ICT emission spectral features by comparing them with a spectral shift dependent on the local polarity of the medium...
January 30, 2018: Nano Letters
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