Cold Ring Research Articles

AGN feedback in action in the molecular gas ring of the Seyfert galaxy NGC 7172

We present new ALMA observations of the CO(3−2) transition and associated 854 μm continuum at 0.06 − 0.3″ resolution, together with new VLT/SINFONI observations of NGC 7172. This is a luminous (bolometric luminosity of ≃1044 erg s−1) Seyfert galaxy that belongs to the Galaxy Activity, Torus, and Outflow Survey (GATOS). The ALMA CO(3−2) observations reveal the presence of a highly inclined cold molecular gas ring with an approximate radius of 3 − 4″ ≃ 540 − 720 pc, which is likely associated with an inner Lindblad resonance of a putative stellar bar. There are noncircular motions in the VLT/SINFONI [Si VI]λ1.96 μm and H2 at 2.12 μm, and ALMA CO(3−2) velocity fields. After subtracting the stellar velocity field, we detected [Si VI] blueshifted velocities of a few hundred km s−1 to the south of the active galactic nucleus (AGN) position. They trace outflowing ionized gas outside the plane of the galaxy and out to projected distances of ≃200 pc. The CO(3−2) position-velocity diagram along the kinematic minor axis displays noncircular motions with observed velocities of up to ∼150 km s−1. Assuming that these are taking place in the disk of the galaxy, the observed velocity signs imply that the molecular gas ring is not only rotating but also outflowing. We derived an integrated cold molecular gas mass outflow rate of ∼40 M⊙ yr−1 for the ring. Using the ALMA 854 μm extended emission map, we resolved a 32 pc radius torus with a gas mass of 8 × 105 M⊙. These torus properties are similar to other Seyfert galaxies in the GATOS sample. We measured a decreased cold molecular gas concentration in the nuclear-torus region relative to the circumnuclear region when compared to other less luminous Seyfert galaxies. We conclude that the effects of AGN feedback in NGC 7172, which are likely caused by the AGN wind and/or the moderate luminosity radio jet, are seen as a large-scale outflowing molecular gas ring and accompanying redistribution of molecular gas in the nuclear regions.

On the Evolution of Tropopause Layer Cooling Over Tropical Cyclone

AbstractThis study investigates the evolution of tropopause layer cooling (TLC) in an idealized tropical cyclone (TC) as well as the physical mechanism for its formation throughout its lifetime. TLC development is closely related to the intensity change of the TC. The TLC within the inner core of a TC coincides with the occurrence of the TC warm core, whereas the enhancement of the TLC precedes the strengthening of the warm core and the intensification of the TC. This phenomenon suggests that the TLC could be a valuable signal for predicting TC intensity and intensity change. After the onset of rapid intensification, the TLC continues to enhance until it is replaced by the warm core in the inner core region, and it expands to the outer core area and forms a cold ring above the TC outflow layer. The budget analyses of the azimuthal mean potential temperature indicate that advection plays a leading role during all stages of the TLC evolution. Prior to and during the rapid intensification stages of a TC, advection (due to eddy motion) contributes to a cooling of the upper layer above the TC center. This upper‐level cooling is assumed to be related to the uplift caused by overshooting and convection within the inner core. However, the advection process caused by the azimuthal vertical motion dominated the broad cooling across the whole TLC area.

The Apparent Absence of Forward Scattering in the HD 53143 Debris Disk

HD 53143 is a mature Sun-like star and host to a broad disk of dusty debris, including a cold outer ring of planetesimals near 90 au. Unlike most other inclined debris disks imaged at visible wavelengths, the cold disk around HD 53143 appears as disconnected “arcs” of material, with no forward-scattering side detected to date. We present new, deeper Hubble Space Telescope Imaging Spectrograph coronagraphic observations of the HD 53143 debris disk and show that the forward-scattering side of the disk remains undetected. By fitting our KLIP-reduced observations via forward modeling with an optically thin disk model, we show that fitting the visible wavelength images with an azimuthally symmetric disk with unconstrained orientation results in an unphysical edge-on orientation that is at odds with recent ALMA observations, while constraining the orientation to that observed by ALMA results in nearly isotropically scattering dust. We show that the HD 53143 host star exhibits significant stellar variations due to spot rotation and revisit age estimates for this system.

An ∼600 pc View of the Strongly Lensed, Massive Main-sequence Galaxy J0901: A Baryon-dominated, Thick Turbulent Rotating Disk with a Clumpy Cold Gas Ring at z = 2.259

We present a high-resolution kinematic study of the massive main-sequence star-forming galaxy (SFG) SDSS J090122.37+181432.3 (J0901) at z = 2.259, using ∼0.″36 Atacama Large Millimeter/submillimeter Array CO(3–2) and ∼0.″1–0.″5 SINFONI/VLT Hα observations. J0901 is a rare, strongly lensed but otherwise normal massive () main-sequence SFG, offering a unique opportunity to study a typical massive SFG under the microscope of lensing. Through forward dynamical modeling incorporating lensing deflection, we fit the CO and Hα kinematics in the image plane out to about one disk effective radius (R e ∼ 4 kpc) at an ∼600 pc delensed physical resolution along the kinematic major axis. Our results show high intrinsic dispersions of the cold molecular and warm ionized gas (σ 0,mol. ∼ 40 km s−1 and σ 0,ion. ∼ 66 km s−1) that remain constant out to R e; a moderately low dark matter fraction (f DM ∼ 0.3–0.4) within R e; and a centrally peaked Toomre Q parameter—agreeing well with the previously established σ 0 versus z, f DM versus Σbaryon, and Q's radial trends using large-sample non-lensed main-sequence SFGs. Our data further reveal a high stellar mass concentration within ∼1–2 kpc with little molecular gas, and a clumpy molecular gas ring-like structure at R ∼ 2–4 kpc, in line with the inside-out quenching scenario. Our further analysis indicates that J0901 had assembled half of its stellar mass only ∼400 Myr before its observed cosmic time, and the cold gas ring and dense central stellar component are consistent with signposts of a recent wet compaction event of a highly turbulent disk found in recent simulations.

Mechanism of void healing in cold rolled aeroengine M50 bearing steel under electroshocking treatment: A combined experimental and simulation study

M50 bearing steel, as the important material used in aeroengine bearing, exhibits low cold working capacity with high susceptibility to produce voids. This would lead to the deterioration of mechanical property, which critically limits the industrial application of cold ring rolling (CRR) in M50 bearing rings. In this work, the mechanism of void healing in cold rolled aeroengine M50 bearing steel subjected to electroshocking treatment (EST) was investigated by combining experimental and simulation studies. The experimental results obtained using the three-dimensional X-ray microscopy (3D-XRM) technique show that the porosity of the CRR samples decreases from 0.26% to 0.09% after EST. The healing effect of larger voids is not obvious, while small voids are likely to be healed under EST. The simulation results indicate that due to the inhomogeneous distribution of the physical field, the local thermal compressive stress of as high as 2565.9 MPa is generated around the ellipsoidal void and thus drives void healing process. The healing process of ellipsoidal voids under EST can be divided into elastic and plastic deformation stages considering von Mises yield criterion. In the initial stage, only a small elastic deformation of 53.53 nm occurs in the minor axis direction of the void. In the plastic deformation stage, the material flows along the normal direction of the void with a reduction in the aspect ratio, thereby compressing the void surfaces and promoting their healing. Additionally, the degree of void healing depends on the shape characteristics (curvature and aspect ratio) of the void rather than the current direction. This research elucidates a new elastoplastic mechanism of void healing under EST, which also provides a promising prospect for the application of CRR in M50 bearing steel. • In situ characterization of voids before and after EST was realized using 3D-XRM. • A new elastoplastic mechanism of void healing under EST was elucidated. • The driving force of void healing was revealed by analysing the physical field distribution. • The ellipsoidal void is healed with the reduction in the aspect ratio. • The degree of void healing depends on the shape of the void rather than the current direction.

Dust release from cold ring particles as a mechanism of spoke formation in Saturn's rings

Spokes in Saturn's rings are radially-extended structures consisting of dust grains. Although spacecraft and space telescope observations have revealed various detailed features of the spokes and their time variation, their formation mechanism is still under debate. Previous models examined charging mechanisms to attempt at explaining dust release from cm-sized ring particles; however, the attempt has been unsuccessful, because the electrostatic force caused by such charging mechanisms is much weaker than the cohesive force acting on dust grains at ordinary conditions in the ring environment. Here we propose a novel model for the formation of the spokes, where the temperature dependence of cohesion plays an essential role. Ring particles with a temperature below 60 K adsorb an O2 ring atmosphere, which facilitates release of dust grains from them by reduction in the cohesive force between the grains and the particles on the morning ansa. Then, intense electrostatic forces sufficient to overcome the cohesive force are generated on the surface of ring particles and the released dust grains form the structure of spokes. Our model explains observational features of the spokes including their longitudinal location, lifetime, radial expansion velocity, and seasonality.

Distinguishing Characteristics of the Tropical Cyclone Gigantic Jet Environment

AbstractThe meteorological characteristics associated with thunderstorm-top turbulence and tropical cyclone (TC) gigantic jets (GJs) are investigated. Using reanalysis data and observations, the large-scale environment and storm-top structure of three GJ-producing TCs are compared to three non-GJ oceanic thunderstorms observed via low-light camera. Evidence of gravity wave (GW) breaking is manifest in the IR satellite images with cold ring and enhanced-V signatures prevalent in TCs Hilda and Harvey and embedded warm spots in the Dorian and null storms. Statistics from an additional six less prodigious GJ environments are also included as a baseline. Distinguishing features of the TC GJ environment include higher tropopause, colder brightness temperatures, more stable lower stratosphere/distinct tropopause, and reduced tropopause penetration. These factors support enhanced GW breaking near the cloud top (overshoot). The advantage of a higher tropopause is that both electrical conductivity and GW breaking increase with altitude and thus act in tandem to promote charge dilution by increasing the rate at which the screening layer forms as well as enhancing the storm-top mixing. The roles of the upper-level ambient flow and shear are less certain. Environments with significant upper-tropospheric shear may compensate for a lower tropopause by reducing the height of the critical layer which would also promote more intense GW breaking and turbulence near the cloud top.

Polymerization of 2-hydroxyethyl methacrylate by hydro/solvothermal technique in presence of nanographene: electrical and thermal degradation characterization

Nanocomposites of poly(2-hydroxyethyl methacrylate) (PHEMA) loaded with 1.7 mass%, 6.5 mass% and 9.0 mass% nanographene were prepared by hydro/solvothermal technique. The main peaks of the nanographene and amorphous polymer structure were revealed by X-ray diffraction (XRD) analysis. Nanocomposites were characterized by SEM, DSC and TGA techniques. The dielectric constant (eʹ), the dielectric loss factor (eʺ), the loss tangent (tanδ) and the conductivity (σac) were measured using a dielectric analyzer in a frequency range from 100 Hz to 2 kHz. Also, current (I)–voltage (V) measurements were carried out. It is well known that nanocomposite formation causes an improvement of many properties for a polymer, providing enhanced properties such as conductivity and thermal stability. This investigation was done to understand whether the presence of nanographene causes changes in the degradation pathway of poly(HEMA) prepared by hydro/solvothermal technique. For this aim, pure poly(HEMA) and nanocomposites were heated from room temperature to 500 °C. The characterization of degradation products for the cold ring fractions (CRFs) and trapped at − 196 °C (in liquid nitrogen) was investigated by means of FT-IR, 1H, 13C-NMR spectroscopic and GC–MS techniques. The FT-IR, NMR and GC–MS data showed that depolymerization corresponding to monomer (2-hydroxyethyl methacrylate) was the most important product trapped at CRF and − 196 °C in the thermal degradation of nanocomposites. As the nanographene loading increased in composite systems, the rate of depolymerization of poly(HEMA) increased compared to pure poly(HEMA). The nanographene particles in the composite systems acted as a mass barrier that retards the escape of the volatile products

Low Voltage Delay Element with Dynamic Biasing Technique for Fully Integrated Cold-Start in Battery-Assistance DC Energy Harvesting Systems

This paper proposes an ultra-low voltage delay element for battery-assistance DC energy harvesting systems. By inserting a low voltage level shifter (VLS), a wider voltage range is obtained to bias the body of the delay element. Thus, both the voltage transfer curve (VTC) and the DC gain of the delay element are enhanced. Due to the introduction of the VLS, the cold start-up ring oscillator constituted by the proposed delay element can achieve oscillation under an extremely low input voltage. The fully integrated cold start-up ring oscillator with 21 stages of the proposed element is implemented in a standard 180 nm complementary metal oxide semiconductor (CMOS) process. The post-layout experimental results indicate that the cold start-up ring oscillator can retain oscillation when the power supply voltage (VDD) is 24 mV under a typical corner at room temperature. The output voltage swing of the cold start-up ring oscillator based on the proposed delay element is improved by more than 55% under VDD = 40 mV compared with a stacked inverter-based cold start-up ring oscillator. Monte Carlo (MC) simulation from 100 samples shows the enhanced output swing with the proposed delay element under process variation.

Microstructure Evolution and Tempering Transformation Kinetics in a Secondary Hardened M50 Steel Subjected to Cold Ring Rolling

The microstructure evolution and tempering transformation kinetics of the M50 steel subjected to cold ring rolling (CRR) have been investigated. The results indicate that the brass R{110}<110> texture is weakened with the enhancement of the <111>//ND texture during CRR. Due to the increased low angle boundaries by CRR, the Ac1 temperature decreases while the carbon content and volume fraction of RA increase. During tempering, the activation energy of carbon atoms segregation and transition carbide precipitation decrease, while the activation energy of retained austenite (RA) decomposition increases after CRR. The kinetic analysis shows that the CRR is beneficial to the carbon atoms segregation during the beginning of tempering. Then, the CRR leads to the delay of the onset of transition carbide precipitation, but decreases the whole reaction time, which has been verified by the transmission electron microscopy (TEM) and hardness results. The lagging of transition carbide precipitation in the early stage is caused by the increased segregation trapping of carbon atoms, while the higher nucleation rate is responsible for the enhanced precipitation of transition carbide during the later stage. For the cementite formation, there are no significant changes in the predictive kinetics after the applied CRR. However, the kinetic transformation of RA decomposition is inhibited by the CRR, which is attributed to the higher carbon content and smaller grain size of RA. Additionally, the alloy carbides precipitation is also enhanced by the CRR process during secondary hardening.

Water pumping performance of a Cryo–TMP combination pump

There is an increasing need to systematically investigate the performance of commercial Cryo–TMP [in-line Cryogenic Water Pump (CWP) + Turbo Molecular Pump (TMP)] combination pumps. In this study, the factors affecting the pumping speed of water in a Cryo–TMP, such as the number of cold rings, dimensions, shape, etc., are systematically analyzed by Monte Carlo simulation. We constructed a test dome and a Cryo–TMP500 based on the simulation results to measure the strict effective pumping performance of the Cryo–TMP. In addition, we established a systematic measurement method for pumping performance using the Cryo–TMP500 in three experimental modes: TMP-only mode, CWP-off mode, and CWP-on mode. The results show that the water pumping speed of the Cryo–TMP500 with only one cold ring is ∼76% of that of a standalone cryopump (∼30 000 L/s) with the same opening inlet diameter; this speed is 22 550 L/s, which is in good agreement with the simulation result of 23 276 L/s. The pumping speeds for non-condensable gases (H2, N2) are 8%–19% higher than expected.

Observed Deep Anticyclonic Cap Over Caiwei Guyot

AbstractThe mean circulation pattern and its mechanism over Caiwei Guyot (1,308–5,600 m) in the Northwest Pacific were studied utilizing 3 years of in situ data. A deep anticyclonic cap was found to enclose the entire guyot from its bottom up to a depth of 728 m, which is composed of a stable but highly asymmetric anticyclonic circulation at the foot and a bottom‐trapped anticyclonic circulation over the summit. On the slope, the circulation is complex with a dominant anticyclonic circulation near the bottom and a weak cyclonic circulation at ∼2,200 m. The anticyclonic cap intensity over the summit is significantly modulated by the time‐varying impinging flow. An intensified cold ring above the summit edge was observed at Caiwei Guyot, which differs from the cold domes observed over traditional conic seamounts. Further analysis suggests that the impinging flow is primarily responsible for the cap formation, and the M2 tide‐seamount interaction plays a secondary role. The anticyclonic cap may play a role in the local geological distribution.

Frictional behavior during cold ring compression process of aluminum alloy 5052

The friction is the considerable boundary condition in bulk metal forming. In this paper, the ring compression test was used to evaluate the friction coefficient and factor in Coulomb friction model and Tresca friction model for the plastic deformation of aluminum alloy AA5052. The micro-macro analysis method combining surface morphology and micro-texture was used to explore the friction behaviors in AA5052 cold forming process. In general, the magnitude (μ or m) of friction changes before and after a deformation threshold during ring compression. The maximum change rate of the magnitude (μ or m) before and after the deformation threshold is close to 18.5% under the present experimental conditions, and the change rate decreases with increasing loading speed. The lubrication using MoS2 is better than that using oil at lower speeds (0.15 mm/s, 1.5 mm/s), but the lubrications for MoS2 and oil are similar at higher speeds (15 mm/s). The surface roughness, three-dimensional topography, and surface texture of compressed ring have a sudden change around the deformation threshold, which deviate from the previous evolution trend. The increased friction after deformation threshold also promotes the formation of sufficient shear strain layer in the subsurface plane of the compressed ring, and then it hinders the formation of the typical deformation textures with β-oriented line and promotes the appearance of shear textures such as 001110, 111uvw and hkl110 textures.

Effect of prior cold ring rolling on carbide dissolution during the austenitizing process of an M50 bearing steel

The influence of prior cold ring rolling (PCRR) on carbide dissolution during the austenitizing process of an M50 bearing steel was investigated by combining microstructural observations with kinetics analysis. The microstructural results show that the PCRR leads to a reduction in the volume fraction and the mean diameter of the undissolved carbides. The matrix of the as-quenched specimens after PCRR is enriched with more carbon and alloying elements than those without PCRR, which further confirms that the dissolution behavior of the alloy carbides is enhanced by PCRR during the austenitizing process. The kinetics of the transformation from ferrite to austenite (α → γ) without and with PCRR are determined by differential scanning calorimetry (DSC) upon heating. The austenite onset (Ac1) and end (Ac3) temperatures both decrease with as the thickness reduction from the PCRR increases. The activation energy for the α → γ transformation is calculated and shows a significant decline when the PCRR process is applied. In addition, the PCRR process results in a slight increase in the hardness regardless of the austenitizing temperature.

Three-dimensional thermohaline anomaly structures of rings in the Kuroshio Extension region

Using AVISO satellite altimeter observations during 1993–2015 and a manual eddy detection method, a total of 276 anticyclonic rings and 242 cyclonic rings shed from the Kuroshio Extension (KE) were identified, and their three-dimensional (3D) anomaly structures were further reconstructd based on the Argo float data and the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) cruise and buoy data through an interpolation method. It is found that the cyclonic (anticyclonic) rings presented consistent negative (positive) anomalies of potential temperature; meanwhile the relevant maximum anomaly center became increasingly shallow for the cyclonic rings whereas it went deeper for the anticyclonic rings as the potential temperature anomaly decreased from the west to the east. The above deepening or shoaling trend is associated with the zonal change of the depth of the main thermocline. Moreover, the composite cold ring between 140° and 150°E was found to exhibit a double-core vertical structure due to the existence of mode water with low potential vorticity. Specifically, a relatively large negative (positive) salinity anomaly and a small positive (negative) one appeared for the composite cyclonic (anticyclonic) ring at the depth above and below 600 m, respectively. The underlying driving force for the temperature and salinity anomaly of the composite rings was also attempted, which varies depending on the intensity of the background current and the temperature and salinity fields in different areas of the KE region, and the rings’ influences on the temperature and salinity could reach deeper than 1 000 m on average.

Effect of Cold Ring Rolling on the Wear Resistance of GCr15 Bearing Steel after Quenching and Tempering

In this work, the effects on dry wear behavior of cold ring rolling (CRR) of GCr15 bearing steel, after quenching and tempering (QT) heat treatment are investigated. The effects on steel microstructures and wear mechanisms of CRR with different austenitizing times are also discussed. The results show that, with a short austenitizing time of 10 min, CRR can increase the retained austenite content, decrease the undissolved carbide content and improve the hardness of the specimen, thus reducing ploughing and fatigue flaking, and decreasing the wear loss of the CRR specimen. With the longer austenitizing time of 20 min, the retained austenite content increases, the undissolved carbide content decreases, and the hardness increases significantly, both in specimens with and without CRR, so that ploughing, fatigue flaking, and wear loss can all be decreased. However, with an austenitizing time of less than 20 min, the effects of CRR on retained austenite content, undissolved carbide content, and hardness are not significant. Thus, CRR of less than 20 min cannot further improve wear morphology or decrease wear loss.

Variation of the friction conditions in cold ring compression tests of medium carbon steel

Lubrication and friction conditions vary with deformation during metal forming processes. Significant macro-variations can be observed when a threshold of deformation is reached. This study shows that during the cold compression processing of #45 (AISI 1045) steel rings, the magnitude of friction and surface roughness (Ra) changes significantly upon reaching a 45% reduction in ring height. For example, the Ra of compressed ring specimens increased by approximately 55% immediately before and after reaching this threshold, compared to an 18% or 25%variation over a 35%-45% or a 45%-55% reduction in height, respectively. The ring compression test conducted by this study indicates that the Coulomb friction coefficient μ and Tresca friction factor m are 0.105 and 0.22, respectively, when the reduction in height is less than 45%; and 0.11 and 0.24, respectively, when the reduction in height is greater than 45%.

Numerical and experimental investigations on the effect of mandrel feeding speed for high-speed rail bearing inner ring

In this paper, the effect of mandrel feeding speed was investigated numerically and experimentally for the inner ring of high-speed rail bearing made of GCr15. Firstly, the cold ring rolling process is simulated systematically using nonlinear finite element software package of ABAQUS. Nonlinear constitutive equation was employed to study rolling torque for material GCr15. Secondly, the effect of mandrel feeding speed modes on rolling torque was presented to find an optimized feeding speed mode. To verify the numerical results, cold ring rolling experiment was carried out. The agreement of the roundness of the inner ring and rolling torque between predicted and experimental is good. In addition, the metallographic experiment of the bearing ring before and after cold ring rolling was conducted to obtain microstructure of the part. The scanning electron microscope (SEM) technique was used to capture the sample before and after the process. It was observed that there were a small amount of spherical cementites and lamellar pearlites, and black carbide particles distributed uniformly in the inner ring, where the grains were significantly refined after cold ring rolling. Good agreement between experimental observation and numerical predictions indicated that the procedures were useful in capture the effect of the mandrel feeding speed for the high-speed rail bearing inner ring of cold ring rolling.

Analysis on Stress Field of Asymmetrical Cold Ring Rolling for High-speed Rail Bearing Inner Ring

In this paper, the finite element model of asymmetric cold ring rolling for high-speed rail bearing inner ring is built by using ABAQUS software and the inner stress field of the ring metal during the whole cold ring rolling process is researched and analyzed, which reveals. The distribution of radial, axial, circumferential and equivalent stress at the bite rolling stage, the stable rolling stage and the fine rolling stage in the asymmetric cold rolling forming process for high-speed rail bearing inner ring were analyzed respectively. The stress in each direction of the ring was found to increase first and then decrease with each stage of cold rolling going. Finally, it tends to be stable. The stress on the contact area between the ring blank and the drive roll and the mandrel is obviously greater than that on the core of ring, and the stress in the core is more uniform.

Don’t use oral benzocaine products for teething, FDA warns

In May, FDA issued a safety communication1www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm608612.htmGoogle Scholar warning health professionals and consumers that OTC benzocaine products should not be used in infants and children younger than 2 years and should only be used in adults and children older than 2 years if there are certain warnings on the drug label. FDA also urged manufacturers to add warnings to their products’ labels about benzocaine’s potential to cause methemoglobinemia, a serious condition that changes the transport of oxygen to body tissues. “These products carry serious risks and provide little to no benefits for treating oral pain,” the statement says. “Due to the significant safety risk of methemoglobinemia, we have urged manufacturers [to] stop marketing OTC oral drug products for treating teething in infants and children younger than 2 years. If companies do not comply, we will take action to remove these products from the market.” Serena Huntington, PharmD, CSPI, managing director at the California Poison Control System–Madera division at Valley Children’s Hospital, said that the way oral benzocaine products are marketed can give parents a false sense of security. “Oral gels and teething gels have pictures of babies on the packaging, so people think it’s safe. They think, ‘They wouldn’t give me something that is toxic for my child,’ ” Huntington said. Huntington added that it’s easy to use too much of the products. “Parents put it on their child’s gums, and the child is fine for 15 minutes. Then the child fusses again, so the parent puts more on. It’s therapeutic error. They think more is better, so they overdose their child.” The consistency of oral gels contributes to potential overdosing, said Edward Bell, PharmD, BCPS, professor of pharmacy practice in the Department of Clinical Sciences at Drake University College of Pharmacy and Health Sciences in Des Moines. “Babies swallow it, or it can wash out of their mouths, so then the parents think they didn’t give enough, so they’ll give some more, and the next thing you know, it’s too much,” Bell said. Communicating with parents about oral benzocaine products presents a challenge because they can simply grab a product off the shelf and head up to the register without going near the pharmacy. Huntington suggests being proactive in alerting parents. “You could put a sign up that says, ‘Child teething? Come to the pharmacist to discuss your options.’ Or you could post the FDA warning, which may prompt questions about why they should or shouldn’t use [these products],” Huntington said. “[Another option is] when you talk to parents about child-resistant caps, you can ask if they have any children who are teething.” Bell said that large chain pharmacies have a corporate responsibility to make policies about oral benzocaine. “They should be telling all of their pharmacists that these products can cause problems and not to sell them without talking to parents first.” Bell encourages pharmacists to be prepared with options for parents of teething children. “The best treatments, the ones that the American Academy of Pediatrics recommends, are basically non-drug treatments, like a teething ring for the child to chew on. There are numerous types that look inviting to children, and parents can buy them online or at the pharmacy,” Bell said, noting that many of the products do not contain bisphenol A, or BPA, an endocrine-disrupting chemical that worries many parents. “Anything cold and hard could work—a cold washcloth the child can chew on, or a cold teething ring. Parents can also wash their hands and use their fingers to rub the child’s gums. But no ice cubes, and nothing they can swallow,” Huntington said. Bell cautioned that the items should not be freezing, however. “Freezing can cause damage. Teething rings can be room temperature, or you can put them in the fridge for a few minutes so they are on the cool side.” Huntington said that if you have questions about oral benzocaine products or suspect that a child presented in your pharmacy has been given too much oral benzocaine—signs of methemoglobinemia include blue lips and nail beds—call your local poison control center at 800-222-1222, or refer the parents to the nearest emergency department.