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Cheng-Lin Yang, Sheng-Dong Zhao, Yue-Sheng Wang
In this paper, experimental evidence of large complete bandgaps in a kind of light-weighted zig-zag lattice structure (ZLS) is presented. Ultrasonic experiments are conducted on the stainless steel slab designed with ZLS to detect the complete bandgaps. Also, the numerical simulations of the experiments by the finite element method are carried out. For comparison, we conduct the same experiments and numerical simulations on the stainless steel slab with straight lattice structure (SLS). Good agreement is obtained between the experimental and numerical results...
October 8, 2016: Ultrasonics
Luiza Cassiano, Juliano Pessan, Livia Comar, Flavia Levy, Cristiane Cardoso, Aline Dionisio, Michele Manarelli, Larissa Grizzo, Ana Carolina Magalhães, Marília Buzalaf
OBJECTIVES: This study analysed the effect of frequency of intake and amount of fluoride in milk on the remineralisation of artificial enamel and dentine caries lesions ex vivo/in situ. MATERIALS AND METHODS: Pre-demineralised bovine enamel and dentine slabs were randomly allocated into 5 groups and fixed in removable appliances used by subjects for 7days in each phase. Each treatment comprised milk containing 2.5ppm fluoride daily (T1), or every other day (T2), 5...
October 13, 2016: Archives of Oral Biology
Marta Dec, Andrzej Puchalski, Anna Nowaczek, Andrzej Wernicki
This study was conducted to identify and evaluate the antimicrobial activity of some Lactobacillus isolates of chicken origin. Among 90 isolates 14 Lactobacillus species were distinguished using MALDI-TOF mass spectrometry and 16S-ARDRA. The dominant species was L. salivarius (34.4%), followed by L. johnsonii (23.3%), L. crispatus (13.3%) and L. reuteri (11.1%). All lactobacilli were screened for antimicrobial activity against wild-type strains of Salmonella enterica, Escherichia coli, and Clostridium perfringens...
March 2016: International Microbiology: the Official Journal of the Spanish Society for Microbiology
Noriyoshi Tsujino, Yu Nishihara, Daisuke Yamazaki, Yusuke Seto, Yuji Higo, Eiichi Takahashi
Seismic shear wave anisotropy is observed in Earth's uppermost lower mantle around several subducted slabs. The anisotropy caused by the deformation-induced crystallographic preferred orientation (CPO) of bridgmanite (perovskite-structured (Mg,Fe)SiO3) is the most plausible explanation for these seismic observations. However, the rheological properties of bridgmanite are largely unknown. Uniaxial deformation experiments have been carried out to determine the deformation texture of bridgmanite, but the dominant slip system (the slip direction and plane) has not been determined...
October 17, 2016: Nature
Bofeng Zhu, Guobin Ren, Beilei Wu, Yixiao Gao, Haisu Li, Shuisheng Jian
In this Letter, we investigate the nanofocusing of hybrid plasmons-phonons-polaritons (SPP-HPhPs) in a graphene-hexagonal boron nitride (h-BN) heterostructure with a graphene coating on a tapered h-BN slab. Compared with the hyperbolic phonon polariton (HPhP) in h-BN, the hybrid SPP-HPhP in a heterostructure exhibits much smaller losses, which is validated through both analytical and numerical methods. Furthermore, the thickness dependent dispersions of a hybrid SPP-HPhP enable the tapered heterostructure to achieve a function of focusing electromagnetic waves...
October 1, 2016: Optics Letters
Yuta Tsuji, Prasad L V K Dasari, S F Elatresh, Roald Hoffmann, N W Ashcroft
In pursuit of new lithium-rich phases and potential electrides within the Li-N phase diagram, we explore theoretically the ground-state structures and electronic properties of Li4N at P = 1 atm. Crystal structure exploration methods based on particle swarm optimization and evolutionary algorithms led to 25 distinct structures, including 23 dynamically stable structures, all quite close to each other in energy, but not in detailed structure. Several additional phases were obtained by following the imaginary phonon modes found in low-energy structures, as well as structures constructed to simulate segregation into Li and Li3N...
October 12, 2016: Journal of the American Chemical Society
Sergey N Britvin, Sergei A Kashtanov, Sergey V Krivovichev, Nikita V Chukanov
The tendency of high-valence xenon to form consolidated oxide structures is herein supported by the study of K4Xe3O12, the first example of a layered xenon perovskite. Xenon seems to be the only non-transition element which can adopt single-cation oxide perovskite frameworks. At the same time, peculiarities of electronic structure of xenon impose specific features on the bonding within a perovskite structure. Weak supramolecular interactions known as aerogen bonds are the linkers maintaining structural integrity of perovskite slabs in K4Xe3O12...
October 12, 2016: Journal of the American Chemical Society
Karthik Selvaraj, Vidhya Sampath, V Sujatha, S Mahalaxmi
AIMS: The aim of this in vitro study was to comparatively evaluate the microshear bond strength (MSBS) of etch-and-rinse and self-etch (ER and SE) bonding systems to dentin pretreated with silver diamine fluoride/potassium iodide (SDF/KI) and nanoleakage at the resin-dentin interface using transmission electron microscope (TEM). SUBJECTS AND METHODS: Seventy-two dentin slabs of 3 mm thickness were prepared from extracted human permanent third molars and divided into four groups (n = 18) based on the dentin surface treatment as follows: (1) ER adhesive bonding without dentin pretreatment; (2) SDF/KI pretreatment of dentin followed by ER adhesive bonding; (3) SE adhesive bonding without dentin pretreatment; and (4) SDF/KI pretreatment of dentin followed by SE adhesive bonding...
July 2016: Indian Journal of Dental Research: Official Publication of Indian Society for Dental Research
Zuzana Benková, Pavol Námer, Peter Cifra
The combined effects of the channel asymmetry and the closed chain topology on the chain extension, structure factor, and the orientation correlations were studied using coarse-grained molecular dynamics simulations for moderate chain lengths. These effects are related to applications in linearization experiments with a DNA molecule in nanofluidic devices. According to the aspect ratio, the channels are classified as a stripe or slabs. The chain segments do not have any freedom to move in the direction of the narrowest stripe size, being approximately the same size as the segment size...
October 12, 2016: Soft Matter
Zhuo Bin Siu, Mansoor B A Jalil, Seng Ghee Tan
In this work we study the effects of in-plane magnetic fields on thin films of the Dirac Semimetal (DSM) Na3Bi where one of the in-plane directions is perpendicular to the k-separation between the two Weyl nodes that exist for each spin orientation. We show numerically that the states localized near the surfaces of these thin films are related to the Fermi arc states in semi-infinite slabs. Due to the anisotropy between the two in-plane directions, the application of a magnetic field along these directions have differing effects...
October 10, 2016: Scientific Reports
Solen Cubukcu, Haluk Yücel
In this study, paraffin was selected as a base material and mixed with different amounts of CaSO4·2H2O and H3BO3 compounds in order to mimic breast tissue. Slab phantoms were produced with suitable mixture ratios of the additives in the melted paraffin. Subsequently, these were characterized in terms of first half-value layer (HVL) in the mammographic X-ray range using a pulse-height spectroscopic analysis with a CdTe detector. Irradiations were performed in the energy range of 23-35 kVp under broad beam conditions from Mo/Mo and Mo/Rh target/filter combinations...
October 7, 2016: Australasian Physical & Engineering Sciences in Medicine
Juho S Lintuvuori, Aidan T Brown, Kevin Stratford, Davide Marenduzzo
We present a lattice Boltzmann study of the hydrodynamics of a fully resolved squirmer, confined in a slab of fluid between two no-slip walls. We show that the coupling between hydrodynamics and short-range repulsive interactions between the swimmer and the surface can lead to hydrodynamic trapping of both pushers and pullers at the wall, and to hydrodynamic oscillations in the case of a pusher. We further show that a pusher moves significantly faster when close to a surface than in the bulk, whereas a puller undergoes a transition between fast motion and a dynamical standstill according to the range of the repulsive interaction...
September 28, 2016: Soft Matter
Taraknath Mandal, Ryan L Marson, Ronald G Larson
We describe a systematic coarse-graining method to study crystallization and predict possible polymorphs of small organic molecules. In this method, a coarse-grained (CG) force field is obtained by inverse-Boltzmann iteration from the radial distribution function of atomistic simulations of the known crystal. With the force field obtained by this method, we show that CG simulations of the drug phenytoin predict growth of a crystalline slab from a melt of phenytoin, allowing determination of the fastest-growing surface, as well as giving the correct lattice parameters and crystal morphology...
October 4, 2016: Soft Matter
Bastiaan Florijn, Corentin Coulais, Martin van Hecke
We experimentally and numerically study the role of geometry for the mechanics of biholar metamaterials, which are quasi-2D slabs of rubber patterned by circular holes of two alternating sizes. We recently showed how the response to uniaxial compression of these metamaterials can be programmed by lateral confinement. In particular, there is a range of confining strains εx for which the resistance to compression becomes non-trivial-non-monotonic or hysteretic-in a range of compressive strains εy. Here we show how the dimensionless geometrical parameters t and χ, which characterize the wall thickness and size ratio of the holes that pattern these metamaterials, can significantly tune these ranges over a wide range...
September 29, 2016: Soft Matter
Barbara Klug, Elisabeth Santigli, Christian Westendorf, Stefan Tangl, Gernot Wimmer, Martin Grube
Background: Oral biofilm studies based on simplified experimental setups are difficult to interpret. Models are limited mostly by the number of bacterial species observed and the insufficiency of artificial media. Few studies have attempted to overcome these limitations and to cultivate native oral biofilm. Aims: This study aimed to grow oral biofilm in vivo before transfer to a biofilm reactor for ex situ incubation. The in vitro survival of this oral biofilm and the changes in bacterial composition over time were observed...
2016: Frontiers in Microbiology
William B Hawley, Richard M Allen, Mark A Richards
The boundary between Earth's strong lithospheric plates and the underlying mantle asthenosphere corresponds to an abrupt seismic velocity decrease and electrical conductivity increase with depth, perhaps indicating a thin, weak layer that may strongly influence plate motion dynamics. The behavior of such a layer at subduction zones remains unexplored. We present a tomographic model, derived from on- and offshore seismic experiments, that reveals a strong low-velocity feature beneath the subducting Juan de Fuca slab along the entire Cascadia subduction zone...
September 23, 2016: Science
James A Guggenheim, Ilaria Bargigia, Andrea Farina, Antonio Pifferi, Hamid Dehghani
A novel straightforward, accessible and efficient approach is presented for performing hyperspectral time-domain diffuse optical spectroscopy to determine the optical properties of samples accurately using geometry specific models. To allow bulk parameter recovery from measured spectra, a set of libraries based on a numerical model of the domain being investigated is developed as opposed to the conventional approach of using an analytical semi-infinite slab approximation, which is known and shown to introduce boundary effects...
September 1, 2016: Biomedical Optics Express
Toshiko Yamazawa, Naotoshi Nakamura, Mari Sato, Chikara Sato
Exocrine glands, e.g., salivary and pancreatic glands, play an important role in digestive enzyme secretion, while endocrine glands, e.g., pancreatic islets, secrete hormones that regulate blood glucose levels. The dysfunction of these secretory organs immediately leads to various diseases, such as diabetes or Sjögren's syndrome, by poorly understood mechanisms. Gland-related diseases have been studied by optical microscopy (OM), and at higher resolution by transmission electron microscopy (TEM) of Epon embedded samples, which necessitates hydrophobic sample pretreatment...
October 2, 2016: Microscopy Research and Technique
Sarah Cheng, Theodore Leng
BACKGROUND AND OBJECTIVES: A method of identifying retinal vascular microaneurysms (MAs) in nonproliferative diabetic retinopathy (NPDR) using swept-source optical coherence tomography (SS-OCT). PATIENTS AND METHODS: SS-OCT images were acquired in 17 eyes with NPDR using prototype SS-OCT device and fluorescein angiography (FA) images were obtained simultaneously. MAs identified on SS-OCT slabs were correlated to MAs identified on FA. RESULTS: MAs were identified in SS-OCT slabs in 15/17 eyes, resulting in NPDR diagnosis rate of 88%...
2016: Clinical Ophthalmology
Weiguang Yao, Thomas E Merchant, Jonathan B Farr
We propose an analytical random walk model for proton dose calculation in a laterally homogeneous medium. A formula for the spatial fluence distribution of primary protons is derived. The variance of the spatial distribution is in the form of a distance-squared law of the angular distribution. To improve the accuracy of dose calculation in the Bragg peak region, the energy spectrum of the protons is used. The accuracy is validated against Monte Carlo simulation in water phantoms with either air gaps or a slab of bone inserted...
October 3, 2016: Physics in Medicine and Biology
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