Unconventional acoustic wave propagation transitions induced by resonant scatterers in the high-density limit.

Experiments on ultrasound propagation through a gel doped with resonant encapsulated microbubbles provided evidence for a discontinuous transition between wave propagation regimes at a critical excitation frequency. Such behavior is unlike that observed for soft materials doped with non-resonant air or through liquid foams, and disagrees with a simple mixture model for the effective sound speed. Here, we study the discontinuous transition by measuring the transition as a function of encapsulated microbubble volume fraction.

Evaluation of the Water Sorption and Solubility Behavior of Different Polymeric Luting Materials.

: The study evaluated the water sorption (WSP) and water solubility (WSL) characteristics of different luting agents over a 180-day water storage period. : Nine luting materials, i.e.

Restaurant Date-Marking Practices Concerning Ready-to-Eat Food Requiring Time and Temperature Control for Safety.

Certain foods are more vulnerable to foodborne pathogen growth and formation of toxins than others. Lack of time and temperature control for these foods can result in the growth of pathogens, such as and lead to foodborne outbreaks. The Food and Drug Administration's (FDA) Food Code classifies these foods as time/temperature control for safety (TCS) foods and details safe cooking, holding, and storing temperatures for these foods.

Critical Role of a Nanometer-Scale Microballoon Shell on Bulk Acoustic Properties of Doped Soft Matter.

A material's acoustic properties depend critically upon porosity. Doping a soft material with gas-filled microballoons permits a controlled variation of the porosity through a scalable fabrication process while generating well-tailored spherical cavities that are impermeable to liquids. However, evidence is lacking of how the nanometer-scale polymeric shell contributes to the overall effective material properties in the regime where the wavelength is comparable to the sample thickness.

Magnetoelastic Effects in Doubly Clamped Electroplated CoFe Microbeam Resonators.

Magnetostrictive CoFe films are fully suspended to produce free-standing, clamped-clamped, microbeam resonators. A negative or positive shift in the resonant frequency is observed for magnetic fields applied parallel or perpendicular to the length of the beam, respectively, confirming the magnetoelastic nature of the shift. Notably, the resonance shifts linearly with higher-bias fields oriented perpendicular to the beam's length.

Retail Deli Slicer Inspection Practices: An EHS-Net Study.

The Centers for Disease Control and Prevention (CDC) estimates that 3,000 people die in the United States each year from foodborne illness, and Listeria monocytogenes causes the third highest number of deaths. Risk assessment data indicate that L. monocytogenes contamination of particularly delicatessen meats sliced at retail is a significant contributor to human listeriosis.

Cuspal Deflection in Premolar Teeth Restored with Bulk-Fill Resin-Based Composite Materials.

The present study investigated the effect of three high-viscosity bulk-fill resin-based composite materials on cuspal deflection in natural teeth. Thirty-two sound maxillary premolar teeth with large slot mesio-occlusal-distal cavities were distributed into four groups (n=8). Three groups were restored with bulk-fill resin composite materials (Tetric EvoCeram Bulk Fill, Ivoclar Vivadent, Schaan, Liechtenstein; x-tra fil, VOCO, Cuxhaven, Germany; and SonicFill, Kerr, Orange, CA, USA) in a single 4-mm increment.

Electronic Transport in Bilayer MoS Encapsulated in HfO.

The exact nature of the interface between a two-dimensional crystal and its environment can have a significant impact on the electronic transport within the crystal, and can place fundamental limitations on transistor performance and long-term functionality. Two-dimensional transition-metal dichalcogenides are a new class of transistor channel material with electronic properties that can be tailored through dielectric engineering of the material/environmental interface. Here, we report electrical transport measurements carried out in the insulating regime of bilayer molybdenum disulfide, which has been encapsulated within a high-κ hafnium oxide dielectric.

Energy Dissipation Pathways in Few-Layer MoS Nanoelectromechanical Systems.

Free standing, atomically thin transition metal dichalcogenides are a new class of ultralightweight nanoelectromechanical systems with potentially game-changing electro- and opto-mechanical properties, however, the energy dissipation pathways that fundamentally limit the performance of these systems is still poorly understood. Here, we identify the dominant energy dissipation pathways in few-layer MoS nanoelectromechanical systems. The low temperature quality factors and resonant frequencies are shown to significantly decrease upon heating to 293 K, and we find the temperature dependence of the energy dissipation can be explained when accounting for both intrinsic and extrinsic damping sources.

Restaurant Food Allergy Practices - Six Selected Sites, United States, 2014.

Food allergies affect an estimated 15 million persons in the United States (1), and are responsible for approximately 30,000 emergency department visits and 150-200 deaths each year (2). Nearly half of reported fatal food allergy reactions over a 13-year period were caused by food from a restaurant or other food service establishment (3). To ascertain the prevalence of food allergy training, training topics, and practices related to food allergies, CDC's Environmental Health Specialists Network (EHS-Net), a collaborative forum of federal agencies and state and local health departments with six sites, interviewed personnel at 278 restaurants.

Chemically exfoliating large sheets of phosphorene via choline chloride urea viscosity-tuning.

Exfoliation of two-dimensional phosphorene from bulk black phosphorous through chemical means is demonstrated where the solvent system of choice (choline chloride urea diluted with ethanol) has the ability to successfully exfoliate large-area multi-layer phosphorene sheets and further protect the flakes from ambient degradation. The intercalant solvent molecules, aided by low-powered sonication, diffuse between the layers of the bulk black phosphorus, allowing for the exfoliation of the multi-layer phosphorene through breaking of the interlayer van der Waals bonds. Through viscosity tuning, the optimal parameters (1:1 ratio between the intercalant and the diluting solvent) at which the exfoliation takes place is determined.

Evidence for Spin Glass Ordering Near the Weak to Strong Localization Transition in Hydrogenated Graphene.

We provide evidence that magnetic moments formed when hydrogen atoms are covalently bound to graphene exhibit spin glass ordering. We observe logarithmic time-dependent relaxations in the remnant magnetoresistance following magnetic field sweeps, as well as strong variances in the remnant magnetoresistance following field-cooled and zero-field-cooled scenarios, which are hallmarks of canonical spin glasses and provide experimental evidence for the hydrogenated graphene spin glass state. Following magnetic field sweeps, and over a relaxation period of several minutes, we measure changes in the resistivity that are more than 3 orders of magnitude larger than what has previously been reported for a two-dimensional spin glass.

Retail Deli Slicer Cleaning Frequency--Six Selected Sites, United States, 2012.

Listeria monocytogenes (Listeria) causes the third highest number of foodborne illness deaths (an estimated 255) in the United States annually, after nontyphoidal Salmonella species and Toxoplasma gondii (1). Deli meats are a major source of listeriosis illnesses, and meats sliced and packaged at retail delis are the major source of listeriosis illnesses attributed to deli meat (4). Mechanical slicers pose cross-contamination risks in delis and are an important source of Listeria cross-contamination.

Evaluation of the efficacy of potassium nitrate and sodium fluoride as desensitizing agents during tooth bleaching treatment—A systematic review and meta-analysis.

Objectives: This meta-analysis was performed to evaluate the efficacy of potassium nitrate and sodium fluoride as desensitizing agents during tooth bleaching treatment.

Data, Sources And Study Selection: An electronic systematic literature search was conducted in Cochrane Center Register of Controlled Trials, MEDLINE (PubMed) and EmBase in April, 2014 in English and without time restrictions. Study information extraction and methodological quality assessments were accomplished by two reviewers independently.

White diet: is it necessary during tooth whitening?

Patients are sometimes blamed for a reduced effect of bleaching when they do not adhere to a dentist's prescribed white diet. This study aimed to determine whether a white diet is necessary by evaluating the effects of coffee, tea, wine, and dark fruits on the potential tooth whitening during the bleaching process. Each of the effects of discoloration was categorized as "yes" or "no" based on a patient questionnaire.

Short-term Efficacy of Agents Containing KNO3 or CPP-ACP in Treatment of Dentin Hypersensitivity.

Objective: To evaluate the short-term efficacy of agents containing KNO3 or casein phosphopeptide- amorphous calcium phosphate (CPP-ACP) in the treatment of dentin hypersensitivity.

Methods: UltraEZ, containing KNO3 and MI Paste, containing CPP-ACP were applied in this study. The dentin hypersensitivity of 102 subjects was established by a tactile stimulus with a Yeaple preasure probe, and the degree of hypersensitivity was measured using a visual analogue scale (VAS).

Effect of Er,Cr:YSGG laser, air abrasion, and silane application on repaired shear bond strength of composites.

Unlabelled: Aged resin composites have a limited number of carbon-carbon double bonds to adhere to a new layer of resin. Study objectives were to 1) evaluate various surface treatments on repaired shear bond strength between aged and new resin composites and 2) to assess the influence of a silane coupling agent after surface treatments.

Methods: Eighty disk-shape resin composite specimens were fabricated and thermocycled 5000 times prior to surface treatment.

Labeled vs actual concentration of bleaching agents.

The purpose of this study was to determine if the actual concentration of bleaching agents available in four different countries were the same as the label indicated and within the recommendations of the International Standard on Tooth Whitening. The method recommended for assaying peroxide by the United States Pharmacopeia was used to determine concentrations. All products in the United States and China were within the standard when products were tested immediately upon delivery at testing sites.

Hydrogenation and fluorination of graphene models: analysis via the average local ionization energy.

We have investigated the use of the average local ionization energy, I[combining overline](S)(r), as a means for rapidly predicting the relative reactivities of different sites on two model graphene surfaces toward the successive addition of one, two, and three hydrogen or fluorine atoms. The I[combining overline](S)(r) results were compared with directly computed interaction energies, at the B3LYP/6-311G(d,p) level. I[combining overline](S)(r) correctly predicts that the edges of graphene sheets are more reactive than the interior portions.

Bilayer graphene grown on 4H-SiC (0001) step-free mesas.

We demonstrate the first successful growth of large-area (200 × 200 μm(2)) bilayer, Bernal stacked, epitaxial graphene (EG) on atomically flat, 4H-SiC (0001) step-free mesas (SFMs) . The use of SFMs for the growth of graphene resulted in the complete elimination of surface step-bunching typically found after EG growth on conventional nominally on-axis SiC (0001) substrates. As a result heights of EG surface features are reduced by at least a factor of 50 from the heights found on conventional substrates.

Surface doping and band gap tunability in hydrogenated graphene.

We report the first observation of the n-type nature of hydrogenated graphene on SiO(2) and demonstrate the conversion of the majority carrier type from electrons to holes using surface doping. Density functional calculations indicate that the carrier type reversal is directly related to the magnitude of the hydrogenated graphene's work function relative to the substrate, which decreases when adsorbates such as water are present. Additionally, we show by temperature-dependent electronic transport measurements that hydrogenating graphene induces a band gap and that in the moderate temperature regime [220-375 K], the band gap has a maximum value at the charge neutrality point, is tunable with an electric field effect, and is higher for higher hydrogen coverage.