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Intertidal flats and salt marshes in channel–shoal environments are at severe risk of drowning under sea level rise (SLR) ultimately ceasing their function of coastal defense. Earlier studies indicated that these environments can be resilient against moderate SLR as their mean height is believed to correlate with tidal amplitude and mean sea level. Recent morphological analyses in the German Wadden Sea on the northwestern European continental shelf contradicted this assumption as mean tidal flat accretion surpassed relative SLR, indicating that nonlinear feedback between SLR, coastal morphodynamics, and tidal dynamics played a role. We explored this relationship in the German Wadden Sea's channel–shoal environment by revisiting the sensitivity of tidal dynamics to observed SLR and coastal bathymetry evolution over one nodal cycle (1997 to 2015) with a numerical model. We found a proportional response of tidal high and low water to SLR when the bathymetry was kept constant. In contrast, coastal bathymetry evolution caused a spatially varying hydrodynamic reaction with both increases and decreases in patterns of tidal characteristics within a few kilometers. An explorative assessment of potential mechanisms suggested that energy dissipation declined near the coast, which we related to a decreasing tidal prism and declining tidal energy import. Our study stresses the fact that an accurate representation of coastal morphology in hindcasts, nowcasts, and ensembles for bathymetry evolution to assess the impact of SLR is needed when using numerical models.

Hydro-numerical models are increasingly important to determine the adequacy and evaluate the effectiveness of potential flood protection measures. However, a significant obstacle in setting up hydro-numerical and associated flood damage models is the tedious and oftentimes prohibitively costly process of acquiring reliable input data, which particularly applies to coastal megacities in developing countries and emerging economies. To help alleviate this problem, this paper explores the usability and reliability of flood models built on open-access data in regions where highly resolved (geo)data are either unavailable or difficult to access yet where knowledge about elements at risk is crucial for mitigation planning. The example of Ho Chi Minh City, Vietnam, is taken to describe a comprehensive but generic methodology for obtaining, processing and applying the required open-access data. The overarching goal of this study is to produce preliminary flood hazard maps that provide first insights into potential flooding hotspots demanding closer attention in subsequent, more detailed risk analyses. As a key novelty, a normalized flood severity index (INFS), which combines flood depth and duration, is proposed to deliver key information in a preliminary flood hazard assessment. This index serves as an indicator that further narrows down the focus to areas where flood hazard is significant. Our approach is validated by a comparison with more than 300 flood samples locally observed during three heavy-rain events in 2010 and 2012 which correspond to INFS-based inundation hotspots in over 73 % of all cases. These findings corroborate the high potential of open-access data in hydro-numerical modeling and the robustness of the newly introduced flood severity index, which may significantly enhance the interpretation and trustworthiness of risk assessments in the future. The proposed approach and developed indicators are generic and may be replicated and adopted in other coastal megacities around the globe.

Stream temperatures have been increasing worldwide, in some cases reaching unsustainable levels for aquatic life. Riparian revegetation has been identified as a strategy for managing stream temperatures by blocking direct solar radiation. In this study, the effects of riparian vegetation on stream temperatures were included within the Soil & Water Assessment Tool (SWAT) model through a shade factor parameter. An equilibrium temperature approach was used to integrate the shade factor in an energy balance context. The stream temperature sub-model was improved using the new energy balance equation and integrated into SWAT. Unlike existing models, the modified SWAT model enables improved representation of two processes – mass and heat transfer – that influence stream temperature change and enables simulation of shading and its effects on stream temperatures at sub-basin scales. The updated SWAT model was tested in Dairy McKay Watershed, OR, USA, for four scenarios: current conditions of riparian vegetation, full restoration, efficient restoration, and no vegetation. The model calibration under current riparian vegetation showed good performance (Nash–Sutcliffe efficiency NSE > 0.74). Stream temperature reduction and number of days with stream temperatures above survival limits (NDSTASL) for aquatic species were also evaluated as measures of riparian shade performance. Findings showed average temperature reductions of 0.91 ∘C (SD = 0.69 ∘C) and reductions in NDSTASL of 17.1 d over a year for full riparian restoration and average reductions of 0.86 ∘C (SD = 0.67 ∘C) and 16.2 d for efficient restoration. Notwithstanding the similar benefits, efficient restoration was 14.4 % cheaper than full riparian vegetation restoration.

The NASA North Atlantic Aerosols and Marine Ecosystems Study (NAAMES) ship and aircraft field campaign deployed to the western subarctic Atlantic between the years 2015 and 2018. One of the primary goals of NAAMES is to improve the understanding of aerosol–cloud interaction (ACI) over the Atlantic Ocean under different seasonal regimes. ACIs currently represent the largest source of uncertainty in global climate models. During three NAAMES field campaigns (NAAMES-1 in November 2015, NAAMES-2 in May 2016, and NAAMES-3 in September 2017), multiple 10 h science flights were conducted using the NASA C-130 aircraft to measure marine boundary layer aerosol and cloud properties. The standard flight pattern includes vertical spirals where the C-130 transitioned from high altitude to low altitude (and vice versa), collecting in situ measurements of aerosols, trace gases, clouds, and meteorological parameters as a function of altitude. We examine the data collected from 37 spirals during the three NAAMES field campaigns, and we present a comprehensive characterization of the vertical profiles of aerosol properties under different synoptic conditions and aerosol regimes. The vertical distribution of submicron aerosol particles exhibited strong seasonal variation, as well as elevated intra-seasonal variability depending on emission sources and aerosol processes in the atmospheric column. Pristine marine conditions and new particle formation were prevalent in the wintertime (NAAMES-1) due to low biogenic emissions from the surface ocean and reduced continental influence. Higher concentrations of submicron aerosol particles were observed in the spring (NAAMES-2) due to strong phytoplankton activity and the arrival of long-range-transported continental plumes in the free troposphere with subsequent entrainment into the marine boundary layer. Biomass burning from boreal wildfires was the main source of aerosol particles in the region during the late summer (NAAMES-3) in both the marine boundary layer and free troposphere.

Marine biogenic particle contributions to atmospheric aerosol concentrations are not well understood though they are important for determining cloud optical and cloud-nucleating properties. Here we examine the relationship between marine aerosol measurements (with satellites and model fields of ocean biology) and meteorological variables during the North Atlantic Aerosols and Marine Ecosystems Study (NAAMES). NAAMES consisted of four field campaigns between November 2015 and April 2018 that aligned with the four major phases of the annual phytoplankton bloom cycle. The FLEXible PARTicle (FLEXPART) Lagrangian particle dispersion model is used to spatiotemporally connect these variables to ship-based aerosol and dimethyl sulfide (DMS) observations. We find that correlations between some aerosol measurements with satellite-measured and modeled variables increase with increasing trajectory length, indicating that biological and meteorological processes over the air mass history are influential for measured particle properties and that using only spatially coincident data would miss correlative connections that are lagged in time. In particular, the marine non-refractory organic aerosol mass correlates with modeled marine net primary production when weighted by 5 d air mass trajectory residence time (r=0.62). This result indicates that non-refractory organic aerosol mass is influenced by biogenic volatile organic compound (VOC) emissions that are typically produced through bacterial degradation of dissolved organic matter, zooplankton grazing on marine phytoplankton, and as a by-product of photosynthesis by phytoplankton stocks during advection into the region. This is further supported by the correlation of non-refractory organic mass with 2 d residence-time-weighted chlorophyll a (r=0.39), a proxy for phytoplankton abundance, and 5 d residence-time-weighted downward shortwave forcing (r=0.58), a requirement for photosynthesis. In contrast, DMS (formed through biological processes in the seawater) and primary marine aerosol (PMA) concentrations showed better correlations with explanatory biological and meteorological variables weighted with shorter air mass residence times, which reflects their localized origin as primary emissions. Aerosol submicron number and mass negatively correlate with sea surface wind speed. The negative correlation is attributed to enhanced PMA concentrations under higher wind speed conditions. We hypothesized that the elevated total particle surface area associated with high PMA concentrations leads to enhanced rates of condensation of VOC oxidation products onto PMA. Given the high deposition velocity of PMA relative to submicron aerosol, PMA can limit the accumulation of secondary aerosol mass. This study provides observational evidence for connections between marine aerosols and underlying ocean biology through complex secondary formation processes, emphasizing the need to consider air mass history in future analyses.

Category: Other; Sports Introduction/Purpose: Patient reported outcome measures (PROMs), especially computerized adaptive testing (CAT), are the gold standard for outcome reporting in the field of orthopaedic surgery. Wearable technology (fitbit, apple watch, etc) and other health monitoring capabilities available on smart phones applications (i.e. apple health) are rapidly evolving and being considered as alternative methods of measuring outcomes in orthopaedics. This patient wearable outcome (PWO) method has yet to be directly compared to PROMs, nor evaluated as a viable option for outcome measurement in orthopaedics. The purpose of this study is to directly compare PWOs to PROMs and determine the advantages and disadvantages of using the health monitoring capabilities of smart phones as outcome measuring tools in orthopaedics. Methods: This study is designed as a nonrandomized prospective cohort focused on a small subset of subjects within the field of orthopaedics. Subjects were recruited from an orthopaedic foot and ankle clinic with diagnoses of ankle sprain, plantar fasciitis, and achilles tendonitis. These conditions were chosen as these would generally represent nonoperative conditions at presentation. Subjects under 16 years of age and surgical candidates were ineligible. Standard PROM surveys, all of which have been previously validated by the AOFAS for outcome measurement were administered at enrollment and then electronically delivered at 3 and 7 weeks. Surveys utilized were the Foot and Ankle Ability Measure (FAAM), Visual Analog Scale (VAS), and PROMIS physical function, mobility and pain interference scores. An application (ActiveTrack) is installed on the subjects' smartphones to pull all past and future health data including step counts, distance traveled, etc. Statistical analysis was then performed to correlate PWO's with PROMs. Results: 28 subjects consented and enrolled in the study. This has provided strong encouragement for the goals of the study. 21 patients were observed at 3 weeks with a Pearson correlation of step count of 0.6975 (95% CI: 0.3804-0.8679). 7 subjects were observed at 7 weeks with a Pearson correlation of step count of 0.8387 (95% CI: 0.2325-0.9756). We found that step counts and FAAM scores generally increased after treatment, and that the correlation between the changes was positive. The strongest signal was obtained from the FAAM ADL subscale. Conclusion: This study shows that there is a correlation between a patient's self-reported function (PROMs) and their activity (PWOs). PWO data may represent a more accurate measurement of a patient's activity and therefore may be a great tool in assessing functionality before and after an intervention (be it surgical or nonoperative treatments). Further analysis of the data obtained from this prospective study over time may help establish a new standard of care for measuring patients' response to orthopaedic treatment.

Abstract Endosymbiont bacteria can affect biological parameters and reduce the effectiveness of natural enemies in controlling the target insect. The objective of this work was to identify endosymbiont bacteria in Anaphes nitens (Girault, 1928) (Hymenoptera: Mymaridae), the main natural enemy used to manage Gonipterus platensis (Marelli, 1926) (Coleoptera: Curculionidae). Genomic DNA from six A. nitens populations was extracted and polymerase chain reactions (PCR) were performed with the primers to detect endosymbiont bacteria in this insect. The PCR products were amplified, sequenced, and compared with sequences deposited in the GenBank for the bacteria identification. All A. nitens populations had the bacterium Yersinia massiliensis (Enterobacteriales: Enterobacteriaceae). This bacterium was originally described as free-living, and it is associated with and composes part of the A. nitens microbiota. This is the first report of Y. massiliensis in an insect host.

In this work, we describe a microfluidic three-dimensional (3D) chondrocyte culture mimicking in vivo articular chondrocyte morphology, cell distribution, metabolism, and gene expression. This has been accomplished by establishing a physiologic nutrient diffusion gradient across the simulated matrix, while geometric design constraints of the microchambers drive native-like cellular behavior. Primary equine chondrocytes remained viable for the extended culture time of 3 weeks and maintained the low metabolic activity and high Sox9, aggrecan, and Col2 expression typical of articular chondrocytes. Our microfluidic 3D chondrocyte microtissues were further exposed to inflammatory cytokines to establish an animal-free, in vitro osteoarthritis model. Results of our study indicate that our microtissue model emulates the basic characteristics of native cartilage and responds to biochemical injury, thus providing a new foundation for exploration of osteoarthritis pathophysiology in both human and veterinary patients. Keywords: Organ-on-a-Chip, Cartilage, Primary cells, Tissue-on-a-Chip

Fraction arithmetic facility is fundamental to learning more advanced math topics. However, attaining the ability to add and subtract fractions is hard for many students. The present longitudinal study examined students' growth on simple addition and subtraction word problems between fourth and sixth grades (N = 536). Latent class growth analyses revealed three empirically distinct growth trajectories: (a) "consistently accurate" students who displayed high accuracy across time; (b) "high-growth" students who demonstrated low initial accuracy but made subsequent growth; and (c) "low-growth" students who demonstrated consistently poor accuracy across time. Age and whole number calculation fluency predicted membership in the consistently accurate and high-growth classes relative to membership in the low-growth class. Language and nonverbal reasoning skills were identified as predictors of student membership in the consistently accurate versus low-growth class. Low-growth students displayed more whole number bias and calculation errors compared with students who demonstrated growth. Findings reveal that a concerning subset of students make little to no progress in simple fraction arithmetic computation, despite several years of fractions instruction in school.

In the food industry, the efficient production of high quality products leads to increased investigation efforts in the production process. High shear rates, improper heat transfer during the production process can lead to low quality products. In many cases the produced food preparation contains additives e.g. pectin and starch, which are affecting the products flow behaviour especially at lower temperatures. High shear rates during the production can be observed rather during the cooling and mixing processes of these products. The goal of this paper is to develop a CFD solver in the open source software OpenFOAM® which will be able to recognise the weak spots of the production. For this purpose, a detailed analysis of the material properties was completed with the help of measurements. In the food industry, the average volume of a produced batch is up to 1,000 L. To speed up the development of the CFD code a model production process was set up in small scale using a 10 L stainless steel vessel with a simple mixer blade and heating/cooling jacket. The temperature of the medium inside the vessel was measured at various points. The torque of the shaft of the rotor blade was also measured during the production time. Using these measurement results the CFD computation could be validated. For the computed medium a shear rate and temperature dependent viscosity and a temperature dependent heat capacity, thermal conductivity and density model was created. To calculate the mixing during the process, dynamic mesh using the AMI concept was applied. The industrial cooling processes takes up to 30 min, but considering the inefficient mixer blade and the weak cooling power the cooling time at small scale usually takes more time. Because of the high computational need and relatively small time steps the simulation was calculated only for 25 min real time. The data of the installed PT 100 temperature sensors and the measured torque showed a close agreement with the simulation results.

Adsorption is one of the most often used unit operations in chemical engineering. However, due to computational limitations and time constraints simulations of adsorption processes are commonly done only with black box models or simplified porous media structures. In a new project an OpenFOAM® based CFD solver adsorpFoam, the required grid generation work flow using DEM methods for random packings and also post processing tools were created to carry out extended analyses of adsorption columns. Fully resolved packed beds were simulated to get more detailed information on gas side inhomogeneous distribution, bypass streams and near-wall effects (all these factors contribute to the total pressure drop of the packing), as well as fluid residence time distributions of random packings in columns. The current work will summarize the first results of adsorpFoam with respect to the validation using gas flow in laboratory scale random packings: The code and the procedure have been tested for spheres, mono- dispersed cylinders and cylindrical particles with size distribution. In all cases, a good agreement of the experimental results and the CFD simulations has been achieved. In a next stage of the project multi-component adsorption kinetics will be investigated, which are influenced by the local flow and temperature profile. Compared to common porous media CFD approaches a more realistic and reasonable residence time distribution can be achieved with this method.

Membrane processes play an important role in gas separation because they are robust and energy efficient. In the last decades a large number of studies have been carried out on this topic. Most of these studies were experimental, black box modelling or one-dimensional process modelling, but just a few applied Computational Fluid Dynamics (CFD) to have a more detailed look at these processes. In addition to experimental investigation CFD can provide more detailed insights on the local flow, the concentration profiles which influence the equilibrium and the driving force for mass transfer without high costs, and lots of effort. Compared to black box modelling and process simulation CFD can also resolve all three spatial dimensions and this is valuable for the investigation of phenomena which are space dependent,e.g. local mixing in the membranes or concentration polarization. In the current study a new CFD solver was developed. The new solver is based on the open source code OpenFOAM® for CFD modelling of membranes using solution-diffusion mechanism. It was validated and calibrated against processes simulation codes and also experiments. The solver was used for the investigation of a geometrical parameter on the design of hollow fibre membrane modules. The effect of permeate outlet positioning (membrane module flow regime) on the quality of separation of a biogas mixture was carried out.

Monoterpenes are an important class of biogenic hydrocarbons that influence ambient air quality and are a principle source of secondary organic aerosol (SOA). Emitted from vegetation, monoterpenes are a product of photosynthesis and act as a response to a variety of environmental factors. Most parameterizations of monoterpene emissions are based on clear weather models that do not take into account episodic conditions that can drastically change production and release rates into the atmosphere. Here, the monoterpene dataset from the rural Thompson Farm measurement site in Durham, New Hampshire is examined in the context of a set of known severe storm events. While some storm systems had a negligible influence on ambient monoterpene mixing ratios, the average storm event increased mixing ratios by 0.59 ± 0.21 ppbv, a factor of 93% above pre-storm levels. In some events, mixing ratios reached the 10's of ppbv range and persisted overnight. These mixing ratios correspond to increases in the monoterpene emission rate, ranging from 120 to 1240 g km−2 h−1 compared to an estimated clear weather rate of 116 to 193 g km−2 h−1. Considering the regularity of storm events over most forested areas, this could be an important factor to consider when modeling global monoterpene emissions and their resulting influence on the formation of organic aerosols.

Toluene was measured using both a gas chromatographic system (GC), with a flame ionization detector (FID), and a proton transfer reaction-mass spectrometer (PTR-MS) at the AIRMAP atmospheric monitoring station Thompson Farm (THF) in rural Durham, NH during the summer of 2004. Simultaneous measurements of monoterpenes, including α- and β-pinene, camphene, Δ 3-carene, and d-limonene, by GC-FID demonstrated large enhancements in monoterpene mixing ratios relative to toluene, with median and maximum enhancement ratios of ~2 and ~30, respectively. A detailed comparison between the GC-FID and PTR-MS toluene measurements was conducted to test the specificity of PTR-MS for atmospheric toluene measurements under conditions often dominated by biogenic emissions. We derived quantitative estimates of potential interferences in the PTR-MS toluene measurements related to sampling and analysis of monoterpenes, including fragmentation of the monoterpenes and some of their primary carbonyl oxidation products via reactions with H3O+, O2+ and NO+ in the PTR-MS drift tube. The PTR-MS and GC-FID toluene measurements were in good quantitative agreement and the two systems tracked one another well from the instrumental limits of detection to maximum mixing ratios of ~0.5 ppbv. A correlation plot of the PTR-MS versus GC-FID toluene measurements was described by the least squares regression equation y=(1.13± 0.02)x−(0.008±0.003) ppbv, suggesting a small ~13% positive bias in the PTR-MS measurements. The bias corresponded with a ~0.055 ppbv difference at the highest measured toluene level. The two systems agreed quantitatively within the combined 1σ measurement precisions for 60% of the measurements. Discrepancies in the measured mixing ratios were not well correlated with enhancements in the monoterpenes. Better quantitative agreement between the two systems was obtained by correcting the PTR-MS measurements for contributions from monoterpene fragmentation in the PTR-MS drift tube; however, the improvement was minor (

A long-term, high time-resolution volatile organic compound (VOC) data set from a ground site that experiences urban, rural, and marine influences in the Northeastern United States is presented. A proton-transfer-reaction mass spectrometer (PTR-MS) was used to quantify 15 VOCs: a marine tracer dimethyl sulfide (DMS), a biomass burning tracer acetonitrile, biogenic compounds (monoterpenes, isoprene), oxygenated VOCs (OVOCs: methyl vinyl ketone (MVK) plus methacrolein (MACR), methanol, acetone, methyl ethyl ketone (MEK), acetaldehyde, and acetic acid), and aromatic compounds (benzene, toluene, C8 and C9 aromatics). Time series, overall and seasonal medians, with 10th and 90th percentiles, seasonal mean diurnal profiles, and inter-annual comparisons of mean summer and winter diurnal profiles are shown. Methanol and acetone exhibit the highest overall median mixing ratios 1.44 and 1.02 ppbv, respectively. Comparing the mean diurnal profiles of less well understood compounds (e.g., MEK) with better known compounds (e.g., isoprene, monoterpenes, and MVK + MACR) that undergo various controls on their atmospheric mixing ratios provides insight into possible sources of the lesser known compounds. The constant diurnal value of ~0.7 for the toluene:benzene ratio in winter, may possibly indicate the influence of wood-based heating systems in this region. Methanol exhibits an initial early morning release in summer unlike any other OVOC (or isoprene) and a dramatic late afternoon mixing ratio increase in spring. Although several of the OVOCs appear to have biogenic sources, differences in features observed between isoprene, methanol, acetone, acetaldehyde, and MEK suggest they are produced or emitted in unique ways.

The conversion and combustion of liquid alternative reduction agents to injected into an ironmaking blast furnace depends strongly on the achieved droplet size distribution of the spray. Since direct on site investigation of the spray in the blast furnace raceway is not feasible, a lab scale cold model has been constructed. The spray formation has been analyzed using Particle Image Velocimetry (PIV) and High Speed Imaging. Furthermore Computational Fluid Dynamics (CFD) simulations have been carried out and compared to the experimental findings to help understanding the atomization process and to predict the droplet size distributions.

The purpose of the current work is to investigate the flow behaviour of both a straight and a slightly rotating turbulent free jet by means of CFD and RANS-turbulence modelling. The comparison of simulation results with data from literature as well as own experimental findings is used to assess the applicability of the numerous available turbulence models for the description of the analysed flow. For the experimental analysis a three dimensional Laser-Doppler-Anemometry system is used to measure gas velocity and turbulence intensity. The results of this work clearly indicate that the quality of the CFD simulation strongly depends on the proper choice of the applied approach for turbulence description.

CFD-models have been developed, implemented and validated to study the injection of plastics and heavy oil into the blast furnace raceway. Separate sets of conservation equations are solved for solid and gas phases, accounting also for heterogeneous transport phenomena. The model predictions deliver detailed insight to local conditions in the blast furnace and will be used for the optimisation of operating conditions, also aiming at further improvement of plant efficiency and economics.

In this work models capable to describe processes in the blast furnace are developed. The implementation of a CFD-model accounting for the flow of coke as well as fluids is presented. By applying separate sets of conservation equations the governing balance equations are solved for both phases. Heterogeneous reactions and heat transfer effects are modelled by implementing source terms based on correlations describing the underlying physics. This model setup has been successfully validated using a number of heat transfer problems as well as setups including heterogeneous and homogeneous chemical reactions.

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Filgratism (granulocyte colony stimulating factor, G-CSF)-mobilized peripheral blood progenitor cells (PBPCs) have replaced bone marrow (BM) as a preferred source of autologous stem cells, in light of the faster hematologic recovery and lesser supportive care requirement exhibited by PBPC transplants. Other hematopoietic stem cells, like the human umbilical cord blood-derived stem cells (hUCBs), and nonhematopoietic stem cells have been shown to improve motor function in rodent models of injury and degenerative disease. In the present study we transplanted either G-CSF-mobilized PBPCs or hUCBs in rats 24 h after permanent middle cerebral artery occlusion (MCAO), and assessed their behavioral abnormalities in spontaneous activity and spontaneous motor asymmetry. In both transplanted groups of rats we observed a significant reduction of the stroke-induced hyperactivity compared with nontransplanted, stroked animals. In addition, transplantation of G-CSF PBPC and hUCB cells prevented the development of extensive motor asymmetry. Our findings raise the possibility that PBPCs could provide a novel transplantation therapy to treat stroke.

The canonical Wnt/β-catenin pathway is involved in the formation of craniofacial skeleton and oral tissues. Aberrant nuclear localization of β-catenin protein has been described in several human diseases including a subset of odontogenic tumors thereby suggesting an important role in tumor development. Fibro-osseous lesions of the craniofacial skeleton comprise several neoplastic, and reactive mesenchymal proliferations in which β-catenin status is unknown. To study this, we immunostained 171 fibro-osseous lesions for β-catenin protein and, for lesions with nuclear positivity, sequenced exon 3 of the CTNNB1 gene and exon 15 of the APC gene. Nuclear β-catenin immunostaining was detected in 34 (20 %) tumors with no correlation between nuclear positivity and either age, gender, or tissue decalcification status (p = 0.2, 0.17, 0.12, respectively). Absent nuclear β-catenin in fibrous dysplasia was the only diagnostically significant finding (p = 0.0034). A single point mutation at Asp56 of CTNNB1 was identified in one case of ossifying fibroma. A second ossifying fibroma and one desmoplastic fibroma demonstrated point mutations (Glu1317 and Glu1536, respectively [corrected] ) in the APC gene. These findings show that apart from fibrous dysplasia where nuclear β-catenin is rare, nuclear β-catenin staining has limited utility in discriminating among the craniofacial fibro-osseous lesions. The molecular mechanisms underlying nuclear β-catenin accumulation in the positive tumors is unlikely to be mediated by CTNNB1 exon 3 or APC exon 15 mutations in most cases.