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Ceres is a large water-rich dwarf planet located within the asteroid belt. Its surface displays evidence of material sourced from a deep subsurface liquid brine layer within recent geologic time, making it a candidate ocean world with possible present-day activity. However, Ceres lacks a substantial atmosphere and likely does not possess a global magnetic field. Therefore, any material emplaced or exposed on the surface will be subject to weathering by charged particles of solar and galactic origin. We have evaluated the effect of charged particle radiation on material within the near-surface of Ceres and find that the timescale for radiation-induced modification and destruction of organics and endogenic material is ∼100 Myr to 1 Gyr within the top 10-20 cm of the surface. Furthermore, we find that the timescale for sterilization of any putative living organisms contained within material at these depths is500 kyr. Future missions to the surface may therefore consider targeting regions with geologic ages that fall between these two timescales to avoid the risk of backward contamination while ensuring that sampled material is not heavily radiation processed.

Linear features are very common on asteroid surfaces. They are generally formed after impact and provide information about asteroid evolution. This work focuses on a mineralogical and spectral analysis of the main linear features on the 1/Ceres surface, having both tectonic (Samhain Catena’s pit chains) and geomorphic origins, i.e., generated by ejecta material (Occator ejecta, Dantu’s secondary radial chains, secondary radial chains generated from the Urvara impact). The analysis is based on spectral parameters defined by the Dawn’s VIR imaging spectrometer data, as albedo and depths of the bands centered at approximately 2.7, 3.1, 3.4 and 3.9 mm. The geomorphic linear features show spectral variations with respect to the surroundings, i.e., ammoniated phyllosilicates band depth shallowing is caused by the presence of material originating in a different region or dehydration caused by impact. The Samhain Catena does not show any mineralogical variation, due to its tectonic origin. The spectral behavior of Ceres’ linear features is similar to that observed on other asteroids (Vesta, Eros) and can be diagnostic in discerning the origin of linear features. Then, we searched spectral signatures of organics in the Samhain Catena region, since they are expected to form at depth due to internal processes: the absence of such signatures indicates that either they form at a larger depth or that their subsurface distribution is uneven.

The purpose of this study was to identify differences in usage trends for 2 specific pulpal therapy treatments in pediatric patients during an 11-year period from January 1, 2010, through December 31, 2020.Insurance data claims for children aged 2 through 12 years undergoing a pulpotomy or a pulpectomy performed by a general dentist (GD) or pediatric dentist (PD) from 2010 through 2020 were extracted from a dental data warehouse. The state where the provider was located was included in the extracted claim.Rates of undergoing a pulpotomy or pulpectomy declined from 2010 through 2020 (odds ratio [OR], 0.978 or 0.946, respectively; P.001). PDs were more likely to perform pulpotomies than GDs (OR, 1.393; P.001), but PDs were less likely to perform pulpectomies than GDs (OR, 0.225; P.001). Younger patient age was a significant predictor for undergoing pulpotomy treatment for both GDs and PDs (ORs, 0.850 and 0.892, respectively; P .001). With increasing patient age, PDs had increased odds of performing a pulpectomy (OR, 1.030; P.001) and GDs had decreased odds of performing a pulpectomy (OR, 0.995; P = .04). When examining effects according to American Academy of Pediatric Dentistry national membership districts, the trends remained consistent with those above.The percentage of children undergoing pulpotomy and pulpectomy therapy declined from 2010 through 2020 among both GDs and PDs.These changes in pulpal therapy practice might indicate a teaching change in pulpal therapy guidelines, suggesting that less invasive pulpal therapy can be used rather than pulpotomies or pulpectomies.

While we now know much about the volatile-rich world of Ceres from the Dawn mission, the deep interior remains something of an enigma, shrouded by a crust composed of water ice, carbonates, phyllosilicates, salts and clathrate hydrates. While smaller than most active moons or planets, Ceres has many features commonly associated with active, icy bodies including: hydrothermal, cryovolcanic, and tectonic features. Yet on active icy moons tidal heating is a significant component of the thermal budget; it is unclear whether radiogenic heating alone would be sufficient to supply the heat necessary for Ceres' interior to undergo solid-state convection. Here we show that transient asymmetric convection develops as the temperature within the body rises from heat generated by the decay of long-lived radionuclides (e.g., U, Th, K). The onset of transient asymmetric convection may reconcile a number of puzzling features on Ceres including: the missing large craters, Hanami Planum-the region of thickened crust, the gravity and crustal thickness, and the lithospheric stress state represented by the Samhain Catenae. Hemispheric-scale instabilities may also be important in the evolution of small bodies with small cores throughout the solar system, including the small icy moons of Saturn and Uranus as well as Kuiper belt objects. NASA [NNX15AI30G]; National Aeronautics and Space Administration Published version We thank Shijie Zhong, Mike Sori, and an anonymous reviewer for thoughtful and constructive reviews. We thank the Dawn Flight Team at JPL for the development, cruise, orbital insertion, and operations of the Dawn spacecraft at Ceres. We thank the instrument teams at the Max Planck Institute, German Aerospace Center (DLR), Italian National Institute for Astrophysics (INAF), and Planetary Science Institute (PSI) for the acquisition and processing of Dawn data. We thank both of the reviewers for their helpful comments. S.D.K. is supported by NASA award NNX15AI30G from the Dawn at Ceres Guest Investigator Program. Part of the research was carried out at the Jet Propulsion Laboratory (JPL), California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Purpose/objectives To investigate dental students’ perceptions and concerns regarding the COVID‐19 pandemic, their coping strategies and support resources, and their perceived stress levels. Methods A customized 19‐item survey and the perceived stress scale (PSS) were applied to undergraduate dental students from the US, Spain, Ireland, Chile, India, and Brazil between April 10 and July 5, 2020. Linear modeling and mediation analysis were used to explore the relationships among demographics, stressors, coping mechanisms, social support, and stress Results A total of 4475 students responded to the survey. The majority (72.4%) were women, and 52.3% had no COVID‐19 training at the time of the survey. The students reported that they had to accommodate to changes in patient care (96.6%) and didactic learning (95.2%) activities, while 88.5% of the respondents indicated at least one of their courses moved online. Transition to online courses went “smoothly with some troubles” for 51.8% of the respondents, and 48.3% perceived the faculty as prepared for the online transition; however, 45.9% reported feeling extremely concerned about the impact of COVID‐19 on their education. The average PSS score was 21.9 of 40 (moderate stress). Multivariate models were built for participants with full data (n = 3899). Being male, having completed more dental coursework, and perceiving a smoother transition were associated with lower PSS scores; more concern about academic progress was associated with higher PSS. Faculty support mediated the relationship between a smoothness of transition and concern about academic progress and PSS scores Conclusion Stress caused by the pandemic may be alleviated by smoother transition and good faculty support.

Purpose To determine the contemporary educational experiences of predoctoral dental students in the United States and Canada regarding behaviour guidance (BG) of the child patient and assess trends from a previous study in 2004. Methods Data were collected from 32 predoctoral paediatric dentistry programme directors in the United States and Canada via a web-based survey. Results The didactic curriculum hours devoted to the teaching of BG techniques in 2019 are similar to 2004. A majority (60.7%) of programmes do not have a formal assessment of competency with BG techniques. Lectures (n = 28), clinical experience (n = 28) and observation (n = 26) were the most common techniques implemented to teach BG techniques, and tell-show-do (100%), non-verbal communication (82.1%), positive reinforcement (89.3%) and distraction (82.1%) were the techniques that more than 75% of dental students most commonly have hands-on experience with during their dental education. In 2019, students tended to have more hands-on experience with nitrous oxide/oxygen inhalation and less hands-on experience with aversive techniques and sedation. Conclusions The majority of dental schools do not have a formal competency in BG of the child patient. Compared with 2004, nitrous oxide/oxygen is used more by dental students and there is less predoctoral education in aversive BG techniques.

Purpose/objectives Silver diamine fluoride (SDF) is a promising therapy for arresting and preventing caries in difficult to treat, high-risk populations, including institutionalized older adults. This study investigates the knowledge and perceptions about SDF of graduating dental students in multiple U.S. dental schools, as well as their willingness to use SDF in their practices. Methods A survey was designed consisting of 21 total questions: 6 questions regarding students' demographic information and their SDF content exposure contextualization, 8 questions tailored to investigate 2 domains regarding students' knowledge about SDF (properties and indication), and 7 questions aiming to investigate 3 domains regarding students' perceptions about SDF (SDF usefulness, appropriateness of using SDF, and willingness to use SDF when in private practice). The survey was then distributed to graduating dental students at 7 U.S. dental schools. Results A total of 386 surveys (response rate of 55%) was collected from 7 schools in the Spring of 2019. The median score resulting from the SDF content exposure questions was 3 (SD = 1.43) from a range of 0-5. The median score from knowledge about SDF properties was 4 (SD = 1.18) from a range of 0 to 6. In the multivariate analysis, a linear model found that the covariates "SDF Usefulness", "SDF Appropriateness" and "SDF Patient Willingness to Use" were significantly associated with higher student willingness to use SDF (R2 = 0.395). Conclusion The results indicated that the graduating students have a positive perception of SDF regarding its usefulness and appropriateness. Graduating students appear inclined to utilize SDF upon entering private practice.

Background: Streptococcus mutans ( S. mutans) participates in the dental caries process. Titanium dioxide (TiO2) nanoparticles produce reactive oxygen species capable of disrupting bacterial DNA synthesis by creating pores in cell walls and membranes. Objective: The objective of this study was to determine the effect of TiO2 on the disruption of S. mutans biofilm. Methods: This study was conducted in four phases involving a TiO2-containing toothbrush and TiO2 nanoparticles. Each phase was completed using 24 h established S. mutans biofilm growth. Phase one data was collected through a bacterial plating study, assessing biofilm viability. Biofilm mass was evaluated in phase two of the study by measuring S. mutans biofilm grown on microtiter plates following crystal violet staining. The third phase of the study involved a generalized oxygen radical assay to determine the relative amount of oxygen radicals released intracellularly. Phase four of the study included the measurement of insoluble glucan/extracellular polysaccharide (EPS) synthesis using a phenol-sulfuric acid assay. Results: Both exposure time and time intervals had a significant effect on bacterial viability counts ( p = 0.0323 and p = 0.0014, respectively). Bacterial counts after 6 min of exposure were significantly lower than after 2 min ( p = 0.034), compared to the no treatment control ( p = 0.0056). As exposure time increased, the amount of remaining biofilm mass was statistically lower than the no treatment control. Exposure time had a significant effect on oxygen radical production. Both the 30 and 100 nm TiO2 nanoparticles had a significant effect on bacterial mass. The silver nanoparticles and the 30 and 100 nm TiO2 nanoparticles significantly inhibited EPS production. Conclusion: The TiO2-containing toothbrush kills, disrupts, and produces oxygen radicals that disrupt established S. mutans biofilm. TiO2 and silver nanoparticles inhibit EPS production and reduce biofilm mass. The addition of TiO2 to dental products may be effective in reducing cariogenic dental biofilm.

The SARS-CoV-2 pandemic disrupted health care services. Previous reports estimated reductions in demand and supply of dental care services, but actual changes have not been reported. The present report depicts a perspective of trends in claims from private dental practice in the United States during 2019 and 2020.Private dental insurance paid claims data from a data warehouse (encompassing 66+ carriers in the United States) were obtained for children and adults (treatments identified by their American Dental Association Code of Dental Procedures and Nomenclature [CDT]), encompassing a 5% random sample of all records between January 2019 and December 2020. A market-based treatment classification placed CDT codes into one of four categories based on the likelihood of being associated with urgent/emergency care.Claims for 3.8 million patients constituted the 5% random sample for analyses. Substantial drops in the provision of treatment items were quantified for a large segment of private dental insurance plans at a national level, showing differential impacts in dental care categories.Week-by-week, detailed descriptions of demand/availability changes in dental care throughout the first year of the 2020 SARS-CoV-2 pandemic were obtained through contrasting perspectives in 2019. Provision of dental care and associated impacts fluctuated over time subject to treatment urgency, but also modified as the weeks/months of dental office lockdowns ebbed in and out of the dental market.

To the Editor: Stability studies have shown that fatty acids in serum cholesteryl ester (CE),1 triglyceride (TG), and phospholipid (PL) fractions stored at −80 °C are stable for up to 10 years (1); but data on the stability of unfractionated serum fatty acids stored at −80 °C or −20 °C are lacking. Polyunsaturated fatty acids (PUFAs), which are highly sensitive to oxidative degradation, were decreased by 14%–46% in plasma CE, TG, and PL fractions stored for 3 years at −20 °C (2). Butylated hydroxytoluene (BHT) has been tested as an antioxidant to prevent fatty acid degradation. Fatty acids in …

The COVID-19 pandemic continues to disrupt dental practice in the United States. Oral health care workers play an integral role in societal health, yet little is known about their willingness and ability to work during a pandemic.Oral health care workers completed a survey distributed on dental-specific Facebook groups during an 8-week period (May 1-June 30, 2020) about their willingness and ability to work during the COVID-19 pandemic, barriers to working, and willingness to receive a COVID-19 vaccine.Four hundred and fifty-nine surveys were returned. Only 53% of dentists, 33% of dental hygienists, 29% of dental assistants, and 48% of nonclinical staff members would be able to work a normal shift during the pandemic, and even fewer (50%, 18%, 17%, and 38%, respectively) would be willing to work a normal shift. Barriers included caring for family, a second job, and personal obligations, and these were faced by dental assistants and hygienists. Dentists were more likely than hygienists (P.001), assistants (P.001), and nonclinical staff members (P = .014) to receive a COVID-19 vaccine.Oral health care workers have a decreased ability and willingness to report to work during a pandemic, and dentists are significantly more able and willing to work than hygienists and assistants. Dentists are more likely than staff to receive a COVID-19 vaccine.The results of this study may help inform future initiatives of dental workforce readiness during a pandemic. Dentists should be prepared to discuss alterations to standard operating procedures to allay staff members' fears and improve retention rates during pandemics, allowing for improved access to oral health care.

This document presents an assessment of the potential for occurrence of triboelectrification effects resulting from gas and fluid flow through umbilical tubing attached to a typical spacecraft survival suit. The assessment demonstrates that gas and fluid flow through the umbilicals poses no threat to crew safety over expected operational time periods up to 150 hours..

A primary concern of dental care for the child patient is patient safety. Antibiotics and local anesthetics are very commonly used in dental care, making it critical that providers take into account the special considerations when these drugs are used with the child patient. Considerations in medication selection, indications for use, appropriate and safe dosing, suitable prescribing and administration, and potential deleterious effects are discussed. An overview is provided to ensure proper use of antibiotics and local anesthetics for the pediatric patient.

Fraser syndrome is a rare autosomal recessive disorder characterized by renal agenesis, cryptophthalmos, syndactyly, and laryngeal stenosis. Oral manifestations are sparsely described in the literature, and patients with this syndrome might require special dental management considerations because of the associated cardiac, renal, and cognitive defects. In this report, we describe the oral/dental findings in a 22-year-old girl with Fraser syndrome, and discuss the dental management.

OBJECTIVES: The purpose of this study was to use a newly validated method for measuring 21 cis-fatty acids in red blood cell (RBC) membranes to investigate race-ethnic and gender differences in saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA). In addition, two long-chain PUFA, namely, eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), were summed to provide an Omega-3 Index for each participant. This index is considered a cardiovascular risk factor. METHODS: Units (n = 120) of whole blood in EDTA were purchased from BioIVT (Westbury, NY). The demographic make-up of the set was 60:60 men: women. Of the 120 blood donors, 37% were black, 29% were white, and 34% were Hispanic. Average ages were 44 y (black), 48 y (white), and 43 y (Hispanic). Upon arrival, units were washed, treated with 1% BHT, and packed RBC were frozen until time of analysis. Hydrolysis of esters, derivitization with pentafluorobenzyl bromide, gas chromatography, and mass spectrometric detection were carried out to measure the 21 most abundant cis-fatty acid concentrations in RBC, which were converted to weight percentages of total. For the Omega-3 Index, the percentage of totals calculated for EPA and DHA were summed. RESULTS: There were few small (≤1%) race-ethnic differences and no gender differences in the proportions of fatty acids as SFA, MUFA, or PUFA; overall these averaged (SD) 44% (1%), 16% (1%), and 40% (1%), respectively. The Omega-3 Index averaged (SD) 3.5% (1%). One blood donor reached the suggested goal of ≥ 8%, which is associated with low risk for cardiac events. CONCLUSIONS: This small study was undertaken in advance of the U.S. nationally representative survey, NHANES 2019–2020, in which RBC membrane fatty acids will be measured in the same laboratory. It will be interesting to learn whether NHANES will confirm the mostly null demographic findings in RBC fatty acid percentages and the low average Omega-3 Index. FUNDING SOURCES: None.

The author identifies the major problem areas of Black college students as: (1) academic; (2) personal-social; (3) identity; and (4) financial. The interactive aspects of these problem areas are discussed in relation to their implications for teaching. (Author)

After reviewing the literature concerning black students, author states that latter face serious financial, racial, academic and emotional problems in universities. Factors like self-concept, stress, race, culture, learning, values and socioeconomic background have been used to explain these difficulties. Author integrating above factors, presents map of black student development problems. (SE)

The author contends that the important things for culturally specific counseling are intimate association with and experiencing of the culture of the client. (Author)

Systemic non-biologic agents have long been in clinical use in medicine – often with considerable efficacy, albeit with some adverse effects – as with all medications. With the advent of biologic agents, all of which currently are restricted to systemic use, there is a growing need to ensure which agents have the better therapeutic ratio. The non-biologic agents (NBAs) include a range of agents, most especially the corticosteroids (corticosteroids). This study reviews the corticosteroids in systemic use in management of orofacial mucocutaneous diseases; subsequent studies discuss corticosteroid-sparing agents used in the management of orofacial diseases, such as calcineurin inhibitors used to produce immunosuppression; purine synthetase inhibitors; and cytotoxic and other immunomodulatory agents.

Objective Oral lichen planus (OLP) may be linked to psychological disorders. This study investigated psychological factors associated with OLP. Methods A case-control study with incident OLP case patients and age-gender-socio-economic status-matched controls, recruited from among relatives, accompanying persons, and departmental staff, investigated psychological traits using the Psychological General Well-Being Index-Short form. Common factor analysis was used to generate a set of psychological dimensions. The association between these dimensions and OLP adjusted for confounders (education, number of lifetime sexual partners, drinking-smoking) and interactions was assessed through conditional logistic regression and odds ratios (OR) were estimated. Results A total of 67 case-control pairs were recruited. Psychological dimensions generated were: dimension-1 (anxiety, low vitality), dimension-2 (negative well-being, low vitality), dimension-3 (depressed mood, low self-control). The ORs for OLP were, dimension-1, 1.0 (95% confidence interval -95CI, 0.3-2.6); dimension-2, 0.5 (95CI, 0.2-1.2); dimension-3, 4.8 (95CI, 1.8-12.9). Dimension-3 was highly associated with mild, but not associated with severe, OLP. Literature searching provided 21 studies, with anxiety and depression principally associated with OLP. Conclusions Depressed mood and low self-control were highly associated with OLP, particularly the reticular-papular forms. These traits could have a causative role in OLP development-progression, but further investigations are necessary.