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Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are an emerging issue in wastewater treatment. High‐temperature thermal processes, incineration being time‐tested, offer the opportunity to destroy and change the composition of PFAS. The fate of PFAS has been documented through wastewater sludge incinerators, including a multiple hearth furnace (MHF) and a fluidized bed furnace (FBF). The dewatered wastewater sludge feedstock averaged 247‐ and 1280‐μmol targeted PFAS per sample run in MHF and FBF feed, respectively. Stack emissions (reportable for all targeted PFAS from MHF only) averaged 5% of that value with shorter alkyl chain compounds comprising the majority of the targeted PFAS. Wet scrubber water streams accumulated nonpolar fluorinated organics from the furnace exhaust with an average of 0.740‐ and 0.114‐mol Fˉ per sample run, for the MHF and FBF, respectively. Simple alkane PFAS measured at the stack represented 0.5%–4.5% of the total estimated facility greenhouse gas emissions. Practitioner Points: The MHF emitted six short chain PFAS from the stack, which were shorter alkyl chain compounds compared with sludge PFAS.The FBF did not consistently emit reportable PFAS from the stack, but contamination complicated the assessment.Five percent of the MHF sludge molar PFAS load was reported in the stack.MHF and FBF wet scrubber water streams accumulated nonpolar fluorinated organics from the furnace exhaust.Ultra‐short volatile alkane PFAS measured at the stack represented 0.5%–4.5% of the estimated facility greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

Abnormalities of dental development and anatomy may suggest the presence of congenital or acquired anomalies. The detection of abnormalities, therefore, is an important skill for radiologists to achieve. Knowledge of dental embryology and an understanding of the radiologic appearances of teeth at various stages of maturation are required for the appreciation of abnormal dental development. While many tooth abnormalities are well-depicted on dedicated dental radiographs, the first encounter with a dental anomaly may be by a radiologist on a computed tomographic (CT) or magnetic resonance (MR) exam performed for other reasons. This article depicts normal dental anatomy and development, describing the appearance of the neonatal dentition on CT and MRI, the modalities most often encountered by clinical radiologists. The radiology and dental literature are reviewed, and key concepts are illustrated with supplemental cases from our institution. The value of knowledge of dental development is investigated using the analysis of consecutive MR brain examinations. Finally, the anatomical principles are applied to the diagnosis of odontogenic infection on CT. Through analysis of the literature and case data, the contrast of dental pathology with normal anatomy and development facilitates the detection and characterization of both congenital and acquired dental disease. [ABSTRACT FROM AUTHOR]

Purpose: To determine if a virtual externship (VE) is beneficial to potential applicants regarding their perceived knowledge of a pediatric dentistry residency program. Secondarily, this study identified general program characteristics that influence resident ranking decisions. Methods: All applicants who applied to a pediatric dentistry residency program in the Southeast were invited to participate in a VE. Those who participated in the externship (n = 65) were asked to voluntarily complete Pre‐ and Post‐VE surveys. Participants were asked 22 questions about their level of knowledge of both tangible and intangible aspects of the program such as stipend, patient volume, faculty‐resident interaction, and resident comradery. Participants were also asked to rank 9 general characteristics that influence ranking decisions such as geography, cost to attend, and reputation of the program and were asked to rate their satisfaction with the VE. Post‐VE data were compared to pre‐VE data to determine level of knowledge gained via Wilcoxin matched pairs signed rank test (significance set at p < 0.05). Results: When comparing Pre‐ and Post‐VE ratings of level of knowledge about each category, all 22 categories assessed showed statistically significant mean differences indicating perceived knowledge gain with the most knowledge gained for "resident satisfaction in the program." Of the nine program characteristics, clinical experience was the most important factor to participants. Participants (100%) were satisfied with the VE experience and indicated the VE gave them the opportunity to get to know the program. Conclusions: A virtual externship is a satisfactory option for increasing applicant knowledge of the tangible and intangible aspects of a residency program. [ABSTRACT FROM AUTHOR]

Purpose/objectives: To survey potential applicants applying to advanced education in pediatric dental programs and evaluate their preparedness upon graduating from an accredited dental school. Methods: Attendees of a virtual externship of a University program were recruited to participate in a web‐based survey. The survey collected demographic data, current levels of confidence with various pediatric clinical procedures, predicted confidence with those procedures, and number of procedures completed. Chi‐Square and analysis of variance statistics were performed on resulting data to determine statistical significance. Results: Fifty‐three participants completed the survey in its entirety (n = 53). Most respondents reported adequate didactic training, mean score of 3.6 (range 0–5) and a moderate to high impact of coronavirus disease 2019 on their overall training with a mean score of 4.9 (range 0–10). Current dental students reported that they are "not confident at all" (<2.0) for 15/24 (63%) of the procedures. Graduates reported "somewhat confident" (<3.0) for 13/24 (54%) of the categories. Both students and graduates report the lowest levels of confidence for managing dental trauma, invasive treatment of young patients (<4 years of age), and patients with special healthcare needs. Dental students self‐reported the expectation to feel more confident throughout their matriculation; however, their clinical experience was still reported to be limited. Students did not report reaching the level of "confident" for 75% of the procedures. Conclusion: Dental students and recent dental graduates alike perceive themselves to be under prepared for practice and do not feel confident in performing pediatric dental procedures. This study can provide dental schools, program directors, recent graduates, and dental students with an understanding of areas where they are under prepared and could offer areas where curricula and clinical experiences could be updated or modified. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are compounds of emerging concern based on ubiquitous distribution and potential human health impacts. Whereas manufacturing plants and fire-training/suppression areas are recognized as primary sources of PFAS contamination of the environment, understanding the role of water treatment plants (WTPs) and water resource recovery facilities (WRRFs) in PFAS cycling is important. Literature on the presence and pathways of PFAS within and between WTPs and WRRFs was reviewed and synthesized to address this knowledge gap. The production, use, and disposal of PFAS was connected to the water cycle via aquifers/surface water/sediment, drinking water treatment, domestic/industrial water use, domestic/industrial wastewater treatment, the atmosphere, land application, landfills, thermal treatment of wastes, and food production. WTP and WRRF flows release PFAS in liquid-phase, solid-phase, and gas-phase matrices. The purpose of this review is to educate and inform readers of the fate and transport of PFASs throughout the urban water cycle emphasizing the WTP–WRRF connection. Source reduction programs, treatments that interrupt the PFAS cycle, and comprehensive analytical methods are future research needs. [ABSTRACT FROM AUTHOR]

The transport and fate of pesticides applied to nursery crops are not well documented. The major objective of this study was to examine simazine (2-chloro-4,6-bis(ethylamino)-s-triazine), 2,4-D ([2,4-dichlorophenoxy] acetic acid), and [...]

Purpose: Since pediatric zirconia crowns (ZRCs) are prefabricated, they may be sterilized following try-in for re-use. Possible changes in color stability, gloss, and translucency were evaluated for four brands of prefabricated zirconia crowns following autoclave and cold sterilization. Methods: Sixteen maxillary right central incisor prefabricated ZRCs were obtained from NuSmile®, Sprig, Cheng Crowns, and Kinder Krowns® manufacturers and either autoclaved or cold sterilized. Gloss unit measurements were obtained with a small object Novo-Curve glossmeter. CIE-L*a*b* system values were measured with a CM-700d spectrophotometer under three different illuminants to calculate DE (quantitative representation of the perceived color). ΔE equals one was used for perceptibility threshold (PT) and ΔE equals 2.7 for acceptability threshold (AT). Results: All groups' baseline was ΔE less than one for all illuminants except Cheng Crowns to be autoclaved, indicating crowns are not identical in color from the manufacturer. For autoclaving, Cheng Crowns reached ΔE PT greater than one following the 10th sterilization cycle for all illuminants (D65 1.08±0.32 (standard deviation; P<0.001), A equals 1.07±0.32 (P<0.001), and F2 equals 1.25±0.38 (P<0.001). For cold sterilization, Sprig EZCrowns reached PT greater than one for all sterilization cycles, and Cheng Crowns reached ΔE PT greater than one for the sixth and 10th sterilization cycles. Gloss was not affected by either sterilization method. Spring EZcrowns had the highest mean translucency. Conclusions: Although each group may have a slight perceived difference, there was no clinically significant difference in color; all groups remained below the acceptability threshold of ΔE equals 2.7. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to examine the effects of a companion canine on physiologic responses, discomfort level, and behavior in children undergoing sealant placement using a dental isolation system (Isodry®). Methods: Forty-seven healthy six- to 10-year-olds who needed sealants were randomly assigned to a control group (n=23) or experimental group (n=24) that utilized an emotional support canine in the child's lap. Preoperative baseline anxiety was obtained. Pulse, pulse oximetry, and behavior (measured by Frankl and Houpt scales) were recorded at various time points (beginning, at first sealant placement, switching the isolation system to the other side, second side sealant placement, and end) throughout the procedure. Participants reported a comfort level utilizing the FACES scale. Participants in the intervention group were asked, "Did you like having the dog in your lap?" The dentist rated the difficulty of and time required for the procedure. Results: Baseline anxiety was similar; no significant differences in physiologic measurements or FACES ratings were found between groups. The intervention group had significantly lower Houpt ratings for all three variables when the isolation system was repositioned (P=0.002, P=0.03, and P=0.05) and had higher Frankl scores at isolation repositioning and when completing sealants on the second side (P=0.02 and P=0.03, respectively). Both groups had similar ratings from the dentist. Conclusions: Animal-assisted therapy (AAT) should be studied more rigorously to substantiate its effectiveness in enhancing cooperative behavior in children for dental procedures. High levels of satisfaction were observed among pediatric users of AAT. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate depth of cure of an opaque sealant when light cured from increasing tip distances with high irradiance light‐emitting diode (LED) curing units. Methods: Ultraseal XT Plus opaque sealant was cured in a 2 × 2 × 5 mm covered slot mold using LEDs in high irradiance (VALO, SmartLite) or regular mode (Demi Ultra). Curing durations were 9, 15, and 20 seconds for the VALO, SmartLite, and Demi Ultra, respectively. The light tip was placed at three distances from the sealant surface (0, 3, and 5 mm; N = 10/group). Depth of cure was determined at the sealant surface and at 0.5 mm increments using Vicker's hardness (VHN). Results were statistically analyzed using two‐way ANOVA and multiple comparisons (α = 0.05). Results: Depth of cure was significantly affected by the LEDs and light tip distance. At 0.5 mm below the surface, most combinations resulted in hardness higher than 80% of the surface value, except for SmartLite at 3 and 5 mm tip distances and VALO at 5 mm tip distance. Regardless of the tip distance, VALO and Demi Ultra achieved similar VHN values through 1.5 mm depth. Conclusions: It is not likely that sealant is adequately cured with LEDs, even for those in high power mode, when the light tip is moved away from the surface due to lower radiant exposure. [ABSTRACT FROM AUTHOR]

Purpose: To compare fracture strength, failure mode, and chairside time of Class IV fractures restored with CEREC (Chairside Economic Restorations of Esthetic Ceramics) technology or direct composite. Methods: Forty-eight fractured anterior bovine teeth were randomly assigned to three experimental groups (indirect restoration) with margin designs including: A) butt joint, B) short chamfer (one mm), and C) long chamfer (two mm) and a control group (direct composite). Preparations were scanned; restorations were milled from zirconia-reinforced lithium-silicate blocks and cemented. Fracture load (N) and failure mode were analyzed. Techniques were timed from start of margin preparation through finishing. Results were analyzed using one-way analysis of variance or the Kruskal-Wallis test (significance level: P=0.05). Results: Fracture loads (mean±standard deviation) for groups A, B, and C and control group were 2,177±644 N, 2,183±507 N, 2,666±609 N, and 2,358±886 N, respectively (not significantly different; P=0.26). The direct composite was significantly different from all indirect groups (P<0.01) for failure mode. Chairside time was longer for direct restoration. Conclusions: Fracture strength is similar for directly and indirectly fabricated Class IV restorations, with margin design not affecting strength or failure mode. Practitioner's chairside time, but not total time, is reduced when using indirect methods. [ABSTRACT FROM AUTHOR]

The foundation of separation science is the division or deconvolution of a mixture into constituent parts. To do so greatly informs our understanding of complex systems. Equally important is consideration of the behavior of a mixture as a whole—to consider if the whole is the sum of the parts or if individual components interact synergistically or antagonistically when combined. Application of separation science has seldom assumed greater importance than in consideration of the controversy surrounding the traditional and emergent views of the complex chemical system of natural organic matter (NOM). Analyses of simulated and actual environmental water samples using noninvasive separation techniques including flow field‐flow fractionation (flow FFF), excitation–emission matrix (EEM) fluorescence spectroscopy with parallel factor (PARAFAC) analyses, and dynamic light scattering (DLS) are discussed. The data are used to explore whether a distinct chemical category of humic (diagenetic) substances exists in NOM; whether separation of organic matter into fulvic and humic extracts has relevant meaning translatable to actual environmental water samples; whether extraction procedures alter the chemistry of NOM extracts; and, if humic and fulvic acids exist, what physicochemical property or properties make humic substances unique among other forms of NOM. A fluorescence‐based nonoperational definition of humic substances is introduced. The underexplored role of supramolecular, self‐assembled aggregation is presented as a NOM conceptual model. Responses are provided to questions raised in the great NOM debate within a supramolecular context. Core Ideas: A new supramolecular conceptual model invokes strong near‐covalent hydrogen bonding.A nonoperational definition of diagenetic (humic) substances is proposed.Alkali extracts are valid, though imperfect, organic matter proxies.A mechanism for intrinsic chemical recalcitrance of natural organic matter exists.Protection is a "function" of the supramolecular "form." [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate the microleakage of atraumatic glass ionomer restorations with and without silver diammine fluoride (SDF) application. Restorations with SDF are termed silver-modified atraumatic restorations (SMART). Methods: Sixty carious extracted permanent teeth were randomly allocated to two SMART groups and two control groups (n equals 15 per group) for a total of four groups. After selective caries removal, test specimens were treated with 38 percent SDF and polyacrylic acid conditioner was applied and rinsed; teeth were restored with Fuji IX GP® glass ionomer (n equals 15) or with SMART Advantage™ glass ionomer (SAGI; n equals 15). For control groups, specimens were restored with their respective GI material after selective caries removal, both without SDF. Restored teeth were placed in Dulbecco's Phosphate-Buffered Saline solution at 37 degrees Celsius for 24 hours. Teeth were thermocycled between five and 55 degrees Celsius for 1,000 cycles, stained with two percent basic fuchsin, sectioned, and visually inspected for microleakage utilizing stereomicroscopy on a four-point scale. Data were statistically analyzed using Kruskal-Wallis one-way analysis of variance on ranks using Dunn's method (P<0.05). Results: Microleakage between the two SMART restoration groups was insignificant. SAGI alone demonstrated significantly more microleakage than all other groups. There was no statistical significance between the Fuji IX GP® control group and the two SMART restoration groups. Conclusions: This in vitro study indicated that silver diammine fluoride placed before glass ionomer restoration does not increase microleakage. Polyacrylic acid may be used after SDF placement without increasing microleakage. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the effect of different types of instructional styles—traditional lecture with and without video examples and contemporary format that simulated a flipped classroom—on dental students' learning of behavior guidance techniques (BGTs) in pediatric dentistry. The study also sought to determine if students had an improved comfort level with BGTs with these instructional methods, if videos improved learning and comfort with BGTs, and if there were differences in outcomes by gender. All 96 second‐year dental students at one U.S. dental school were recruited to participate in the study in 2017. Students were randomly divided into three groups: contemporary instruction (CI), traditional instruction with video (TIV), and traditional instruction with no video (TI). CI students watched a 20‐minute mini‐lecture and were divided into discussion groups led by calibrated faculty members. TIV students received 50 minutes of traditional lecture with video examples. TI students received a traditional lecture with no video examples. All groups completed a questionnaire prior to and on completion of the course. The questionnaire assessed students' learning and perceptions of the learning experience. All students participated in the course and the assessments, for a 100% response rate. The students' post‐course scores improved for all teaching methods (TI>CI>TIV) with no significant differences among them. CI students rated comfort with BGTs and usefulness of videos higher than the other groups, but the difference was not statistically significant. Students rated their satisfaction with and usefulness of the course high for all groups (>3 on a four‐point scale). Learning style and comfort treating children were not statistically significant by gender. Overall, the students reported high satisfaction with all the teaching methods. Although the differences were not statistically significant, discussion groups were ranked highest in satisfaction and usefulness. [ABSTRACT FROM AUTHOR]

A new conceptual model for supramolecular aggregation of natural organic matter (OM) is proposed. Scientific awareness of OM as natural hydrogels is slowly increasing although in the literature they are primarily categorized as physical hydrogels stabilized only by weak interactions. The supramolecular view of OM is here expanded, based on insight from comprehensive hydrogen bond theory, to include three-center–four-electron near-covalent linkages and introduce a new category of metachemical hydrogels that are neither chemical nor physical hydrogels. Hydrogels are typically classified into chemical (permanent, covalently bonded) or physical (reversible, ionic, hydrophobic, or hydrogen bonded) classes based on crosslinking. However, augmented by contemporary advances in hydrogen bonding theory purporting that not all hydrogen bonds are weak and that some hydrogen bonding motifs result in moderate and strong interactions, the popular supramolecular view of OM is extended to include all types of hydrogen bonds. We propose a new category of hydrogels exists—metachemical hydrogels—as a fundamental component of OM. Strong, near covalent, equally shared hydrogel cross-linkages in the metachemical hydrogel can outcompete water. Here, metachemical (≤1 μm diameter) and physical (>1 μm diameter) hydrogels are described as two primary forms of aggregates observed for OM in a hierarchical 'supramolecular within supramolecular' self-assembling architecture with new information about shear. The metachemical hydrogels are postulated to be encapsulated within a dispersible physical hydrogel scaffold which can form, dissipate, and spontaneously re-form over turbulent/quiescent cycles indicating reversible abiotic self-assembly. The significance of this investigation is to understand the form OM evolved in nature to provide essential functions. The potential for strong intermolecular forces to form a metachemical hydrogel in OM and the concept of a dynamic dual metachemical/physical hydrogel structure was not previously introduced. The metachemical hydrogel construct should inform hydrogen bonded systems in other chemical and biochemical disciplines. Unlabelled Image • The prevailing supramolecular view of OM aggregates is expanded. • A new definition—metachemical hydrogel—is introduced. • Weak, moderate, and strong hydrogen bonds participate in OM self-assembly. • Metachemical and physical hydrogels create hierarchical OM aggregates. • A 'supramolecular within supramolecular' OM architecture is proposed. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate opinions and preferences of parents from various sociodemographics regarding sugar and both natural and artificial non-nutritive sugar substitutes (NNS). Methods: Oral interview surveys were conducted in dental practice settings. Parents were asked about demographics, their consumption of and feelings about sugar and NNS for themselves and their children, and their concerns regarding NNS. Parents were asked about natural and artificial labels and were asked to select snacks/beverages they would purchase for their children. Results: Parents (N equals 100) preferred sugar-sweetened drinks for their children (76 percent), and 78 percent expressed concern about the potential health effects of NNS, especially cancer. Parents felt sugar was safer than NNS and were more positive about natural NNS than artificial ones. More highly educated parents (P = 0.02) were more likely to avoid NNS for their children, and parents of the lowest income level were likely to express ambivalence regarding naturally labeled NNS. Conclusions: Parents are concerned about giving their children NNS and cite cancer as the primary reason. Parents from higher sociodemographic backgrounds are more likely to limit their children's consumption of NNS and have negative feelings about them. Most parents, especially those of higher sociodemographics, are more accepting of natural NNS. [ABSTRACT FROM AUTHOR]

Many technological options now exist for tourism authorities and researchers to understand the movement of different cohorts of tourists within destinations. However, while the merits and challenges of these methods have received attention within tourism literature, the data that results from different methods have rarely been compared. This preliminary study fills this gap by examining data that emanated from two techniques for capturing tracking data: an app that could be downloaded and placed on participants' phones, and a study phone distributed to tourists that it was pre-loaded with a tracking app. The results reveal that these subtly different techniques produce widely varying results. The implications of these differences are discussed, along with recommendations for future research. [ABSTRACT FROM AUTHOR]