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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. 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). 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. A virtual externship is a satisfactory option for increasing applicant knowledge of the tangible and intangible aspects of a residency program.

To survey potential applicants applying to advanced education in pediatric dental programs and evaluate their preparedness upon graduating from an accredited dental school. 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. 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. 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.

The fluorescence of “long dead” terrestrially sourced organic carbon (Aldrich humic acid salt) was compared to “recently dead or excreted” aquatically sourced organic carbon (ornamental pond). This research eliminated the “living” (biologically active) category of organic carbon (by azide treatment and filtration) which prevented organic matter continuing to metabolize due to microbial activity during storage and analysis. The focus in this context is on the diagenetic (fulvic and humic) substances, which are considered the most recalcitrant organic carbon forms in water treatment. The purposes of this research were to investigate (a) what excitation-emission matrix (EEM) spectroscopy and PARAllel FACtor (PARAFAC) analysis (EEM-PARAFAC) modeling reveals about the limitations to the use of terrestrially derived Aldrich Humic Acid as an aquatic organic matter surrogate, (b) potential flaws observed in EEM spectra and incorrect PARAFAC component assignments gathered in contemporaneous studies, and (c) how EEM-PARAFAC modeling can be used to illustrate the continuum in organic matter aging or maturity. Additionally, to expand the analysis, data were compared to previously published PARAFAC models derived from other freshwater sources. An important result of this research was discovery of a PARAFAC component peak observed at the emission (EM) wavelength at 540 nm in Aldrich Humic Acid which has been rarely noted in the literature, and not previously recognized for its potential importance. This research implies that Aldrich humic acid should only be used as an aquatic surrogate with caution, and that it can be a surrogate for terrestrial soil or ore samples.

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. 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.”

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.

Dentists recommend over-the-counter medications for postoperative pain in children, and parents often make dosing errors when administering these medications. The authors compared the dosing accuracy when parents used various measuring devices and aimed to identify risk factors associated with dosing errors.

Environmental context When surface water is disinfected to produce potable drinking water, toxic by-products are generated by reaction with naturally occurring organic matter. The production of trihalomethane disinfection by-products was investigated for different types of well-characterised organic matter from various geographic locations. Increased understanding of the character of organic matter dissolved in water is needed for improving the ability to provide safe water and protect public health. Abstract Trihalomethanes (THMs) – a class of disinfection by-products (DBPs) including chloroform – are produced when natural water is chlorinated. Many THMs are believed to result from the reaction of chlorine with the aromatic structures in humic substances, which can be represented by ultraviolet absorbance at 254nm (UVA). However, in the literature, plots of the specific, or carbon-normalised, UVA (SUVA) compared with the specific, or carbon-normalised, trihalomethane formation potential, THMFP (STHMFP) are poorly correlated. Therefore, well characterised samples of organic matter were obtained from the International Humic Substances Society (IHSS) to study the effect of type (fulvic acid, FA; humic acid, HA), origin (aquatic, terrestrial), geographical source (Nordic, Suwannee River, peat, soil) and pH (6, 9) on the formation of trihalomethanes. In this research, parameters expressed on a weight-average moles-of-humic substance basis were compared with those on a mass-of-carbon basis. Using factorial analysis, SUVA was statistically described by the main effect type (P=0.0044), whereas STHMFP was statistically described by the main effects type (P=0.0078) and origin (P=0.0210). Separate relationships between SUVA and STHMFP normalised to moles of humic substance were defined for aquatic substances (R2=0.9948) and for terrestrial substances (R2=0.9512). The occurrence of aquatically derived fulvic-like humic acid (Suwannee River humic acid) and aquatically derived terrestrial-like humic acid (Nordic humic acid) were observed. Some aquatic substances were capable of generating levels of THMs per mole of humic substance that were greater than or equal to the most reactive terrestrial humic acid.

Tissue-engineered and regenerative medicine products are promising innovative therapies that can address unmet clinical needs. These products are often combinations of cells, scaffolds, and other factors and are complex in both structure and function. Their complexity introduces challenges for product developers to establish novel manufacturing and characterization techniques to ensure that these products are safe and effective prior to clinical trials in humans. Although there are only a few commercial products that are currently in the market, many more tissue-engineered and regenerative medicine products are under development. Therefore, it is the purpose of this article to help product developers in the early stages of product development by providing insight into the Food and Drug Administration (FDA) process and by highlighting some of the key scientific considerations that may be applicable to their products. We provide resources that are publically available from the FDA and others that are of potential interest. As the provided information is general in content, product developers should contact the FDA for feedback regarding their specific products. Also described are ways through which product developers can informally and formally interact with the FDA early in the development process to help in the efficient progression of products toward clinical trials.

Environmental context.Potentially toxic disinfection by-products form when water containing humic and fulvic acids is chlorinated to destroy pathogenic microorganisms. A pulsed electrical discharge was examined for its ability to destroy an aquatic fulvic acid by oxidation. Spectroscopically, changes in the organic structures were observed, but carbon content and disinfection by-products were not reduced. Abstract.A pilot-scale pulsed electrical discharge (PED) system was used to treat Suwannee River fulvic acid (SRFA) as a representative precursor material for the formation of disinfection by-products (DBPs), specifically trihalomethane compounds. Ultraviolet-visible and fluorescence spectroscopy, dissolved organic carbon (DOC), and the trihalomethane formation potential (THMFP) were used as analytical parameters to monitor the effects of treatment on the substrate. The potential for SRFA degradation (5 mg L-1DOC) was examined over 60 min at each of four operational configurations, varying pulse energy and frequency (0.15 J and 60 Hz, 0.15 J and 120 Hz, 0.4 J and 60 Hz, and 0.4 J and 120 Hz) in a factorial design. Statistically significant changes occurred for UV254, EX254EM460, and EX328EM460under selected conditions; however, concomitant changes in DOC and THMFP were not observed. The composition of SRFA changed, but organic carbon was not mineralised to carbon dioxide. In addition to showing degradation by PED, the significance of the preliminary findings of this research was to demonstrate that spectroscopic monitoring of precursor degradation alone can be misleading, and that whereas ultraviolet-visible and fluorescence spectroscopy indicated degradation of precursor compounds, DOC and THMFP measurements were unchanged and did not support the occurrence of mineralisation in this system.

Environmental context. Excretion of pharmaceuticals and their metabolites by humans and animals, flushing unused pharmaceuticals and inadequate water treatment result in the occurrence of these chemicals as pollutants in wastewater, surface water and drinking water. In this research, the pharmaceutical agent acetaminophen (paracetamol, Tylenol) and its glucuronide and sulfate metabolites were examined as a model system for monitoring wastewater influent and effluent. The true risk to ecosystems and humans from the occurrence of pharmaceuticals in our water supply can only be estimated if accurate concentrations of parent pharmaceutical chemicals as well as their metabolites are measured. Abstract. An analytical method was developed to separately determine acetaminophen and its Phase II metabolites, acetaminophen glucuronide and acetaminophen sulfate, from wastewater in a single extract. The method developed will serve as a model for screening for the presence of other non-steroidal pharmaceutical compounds and their Phase II metabolites in wastewater. Acetaminophen glucuronide was not present in the wastewater influent tested to verify the analytical protocol, whereas concentrations of acetaminophen and acetaminophen sulfate in the influent were reproducible over time. A Phase I metabolite, p-aminophenol, was also determined to occur in the wastewater influent. Concentrations of the analytes-of-interest, detected in effluent samples collected after secondary treatment, but before UV treatment, were highly variable and were undetectable after UV treatment before release to surface water.

Environmental Context. Worldwide, surface water is a source of drinking water and is a recipient of wastewater effluents and pollutants. Many surface water bodies undergo a natural, cyclical, diurnal variation in pH between 7 and 9. Most drinking water and wastewater treatment in the United States is conducted between pH 7 and 8. The pH of water undergoing treatment processes directly impacts the ratio of nonionized to ionized chemical form(s) present, which in turn impacts the success rate of contaminant removal. Many organic wastewater-derived contaminants are very water soluble at pH 7?8 and are inadequately treated.  Abstract. Wastewater-derived contaminants (WWDCs) occur in surface water due to inadequate wastewater treatment and subsequently challenge the capabilities of drinking water treatment. Fundamental chemical properties must be understood to reduce the occurrence of known WWDCs and to better anticipate future chemical contaminants of concern to water supplies. To date, examination of the fundamental properties of WWDCs in surface water appears to be completely lacking or inappropriately applied. In this research, the hydrophobicity?ionogenicity profiles of WWDCs reported to occur in surface water were investigated, concentrating primarily on pharmaceuticals and personal care products (PPCPs), steroids, and hormones. Because most water treatment is conducted between pH 7 and 8 and because DOW, the pH-dependent n-octanol?water distribution ratio embodies simultaneously the concepts of hydrophobicity and ionogenicity, DOW at pH 7?8 is presented as an appropriate physicochemical parameter for understanding and regulating water treatment. Although the pH-dependent chemical character of hydrophobicity is not new science, this concept is insufficiently appreciated by scientists, engineers, and practitioners currently engaged in chemical assessment. The extremely hydrophilic character of many WWDCs at pH 7?8, indicated by DOW (the combination of KOW and pKa) not by KOW of the neutral chemical, is proposed as an indicator of occurrence in surface water.

Activated carbon treatment of drinking water is used to remove natural organic matter (NOM) precursors that lead to the formation of disinfection byproducts. The innate hydrophobic nature and macromolecular size of NOM render it amenable to sorption by activated carbon. Batch equilibrium and minicolumn breakthrough adsorption studies were performed using granular activated carbon to treat NOM-contaminated water. Ultraviolet (UV) absorption spectroscopy and flow field-flow fractionation analysis using tandem diode-array and fluorescence detectors were used to monitor the activated carbon sorption of NOM. Using these techniques, it was possible to study activated carbon adsorption properties of UV absorbing, fluorescing and nonfluorescing, polyelectrolytic macromolecules fractionated from the total macromolecular and nonmacromolecular composition of NOM. Adsorption isotherms were constructed at pH 6 and pH 9. Data were described by the traditional and modified Freundlich models. Activated carbon capacity and adsorbability were compared among fractionated molecular subsets of fulvic and humic acids. Preferential adsorption (or adsorptive fractionation) of polyelectrolytic, fluorescing fulvic and humic macromolecules on activated carbon was observed. The significance of observing preferential adsorption on activated carbon of fluorescing macromolecular components relative to nonfluorescing components is that this phenomenon changes the composition of dissolved organic matter remaining in equilibrium in the aqueous phase relative to the composition that existed in the aqueous phase prior to adsorption. Likewise, it changes the composition of dissolved organic matter remaining in equilibrium in the aqueous phase relative to the adsorbed phase. This research increases our understanding of NOM interactions with activated carbon which may lead to improved methods of potable water production.

Patterns of nutrition and exercise throughout the life span may account for differences in health problems of aging. The purpose of this study was to develop and validate a simple life span history questionnaire of dairy food intake and to assess recalled levels of leisure time physical activity over the life span. Volunteers, 98 women and 49 men, completed two nutritional surveys (Criterion Questionnaire, {CRIQ} and Diary Food Index, {INDX}) and a physical activity questionnaire (P-ACTQ) in a test re-test design. The INDX and P-ACTQ consisted of a one to four scale (low to high intake). Dairy food intake averaged 1.4 to 2.3 servings per day with no significant differences in current dairy food intake between decade age categories. When compared to their own recalled 20's decade, dairy food intake declined slightly with age, except for the 80–89 age group which showed an increased intake. Test retest reliability for the INDX was r = 0.64. Validity of the INDX compared to the CRIQ was r = 0.64. All groups showed a decrease in physical activity levels across the life span. The Dairy Food Index holds promise as a simple “global” assessment of dairy food intake for the study of lifetime trends in advancing our understanding of the role of lifetime habits in chronic “lifestyle” diseases.

The ability to characterize molecules whose physical and chemical properties are intimately linked to their diffusion coefficients and molecular weight is important to further understanding of chemical transport in the environment. Flow field-flow fractionation (flow FFF) was used to obtain separations of water-soluble macromolecules of varying molecular weight, including polystyrene sulfonates and humic substances. The separation occurs due to differing diffusion rates for chemical species of differing molecular weight in aqueous solution. Flow FFF uses fluid flow as the mechanism of separation. A model that yields liquid phase diffusion coefficients as a function of molecular weight was utilized to determine molecular weights from degree of separation. Separations of polystyrene sulfonates, a humic acid, and two fulvic acids of known molecular weight were accomplished using flow FFF. The separations obtained were used to develop a relationship between flow FFF separation and species molecular weight. Separations were obtained for humic and fulvic acids of unknown molecular weight.

The recoveries of picloram, picloram-methylester, hexazinone, benzene, and acetophenone from aqueous samples were studied using a commercially available hydrocarbonaceous pre-analysis extraction cartridge, both with and without tetrabutylammonium hydrogen sulfate (TBAHS) in the eluent. Extraction efficiency was found to be dependent on sample loading volume. The results suggest a mixed mechanism of retention involving both "silanophilic" and "hydrophobic" interactions in the absence of tetrabutylammonium ion. The ability of TBAHS to mask surface silanol groups and/or ion-pair with counterionic solutes is invoked to explain the observations. Chromatograms of the solutes obtained on a C18 bonded analytical column in both the presence and absence of TBAHS are also presented.

The article offers gardening tips from readers of "Garden Gate." It outlines the steps for using pipe insulation to avoid long tomato vines from breaking once the tomatoes start growing. It describes the way of making one's own watering can using an empty laundry detergent container. It presents the steps in creating flower-shaped garden paths.

The level of endotoxin in influenza virus vaccine lots was reduced 10- to 20-fold after barium sulfate adsorption-elution. The amount of viral antigen lost was negligible.

A series of benzenesulfonamides and benzamides were investigated as spectrophotometric detectants for amines in liquid chromatography (LC). The amides were prepared by standard synthetic procedures and their LC detectability was determined by measuring the molar absorptivity at the wavelength of maximum absorption and at 254 nm. The 4-methoxybenzamides had the highest absorptivity at 254 nm, thus they should allow for the lowest detection limits. A 6 ng injection of the 4-methoxybenzamide of amphetamine produced a peak 5% of scale with a 5:1 signal to noise ratio. The derivatization of low levels of amphetamine in aqueous solution with 4-methoxybenzoylchloride was accomplished with a 95% yield when the acid chloride to amine ratio was 500 or greater. The chromatographic properties of the amides were investigated on a hydrocarbonaceous stationary phase. The order of elution of an homologous series appears to correlate well with hydrophobic effects; however, hydrophobic effects alone are not sufficient to explain the retention behavior of amides containing different functional groups.

The chromatographic properties of 23 5,5-disubstituted barbiturates and one 5,5-disubstituted-2-thiobarbiturate are described. The log k′ values for these compounds were determined on two octadecylsilane bonded stationary phases using an eluent of methanol/water. Regression analysis was used to describe the relationship of log k′ to log P and pC. The molecular connectivity indices (χ) through the sixth order were calculated for the 24 barbiturates and compared with the log k′, log P, and pC data. The χ terms are numerical values which are fundamental in definition and describe quantitatively the adjacency relationships in the molecular structure. High correlations were observed between measured log k′ values and the molecular connectivity indices. The same structural features were important to the reversed-phase retention of barbiturates regardless of mobile phase composition or column. The χ terms were also highly correlated with pC and log P.

Solid-phase extraction is an emerging chromatographic sample preparation technology. It is an improved alternative to traditional methods of extracting and concentrating organic compounds from aqueous solutions. Successful application of solid-phase extraction to aqueous environmental samples is illustrated for the trace enrichment of herbicide residues. Because retention and elution are confounded during solid-phase extraction method development, it is difficult to optimize one before the other. A plan for developing single-residue analytical protocols is discussed, and the influence of pH, sample concentration and volume, sorbent mass, and solvent strength and volume on the removal of trace organics from water is illustrated.

The reversed-phase liquid chromatographic elution properties of some isomeric benzamides are reported. The ortho isomer for each series of compounds displays retention properties dissimilar to its meta and para counterparts. Enhanced chromatographic retention occurs in those ortho-substituted benzamides capable of forming an intramolecular hydrogen bond. For those substituents incapable of internal hydrogen-bond formation the ortho isomer displays reduced retention relative to the meta and para isomers.

Sensitized murine spleen cells decrease the spread of influenza infection in cell cultures derived from human and syngeneic murine tissues. This control of infection is immune-specific and can be induced by immunization with identical hemagglutinin or neuraminidase antigens. The antiviral effect is evident in the absence of added immune serum and can be blocked by adsorption of sensitized spleen cells with antiserum to murine IgG. The antiviral effect persists despite separation by agar of the sensitized spleen cells from the virus-infected monolayer. Spleen cells that do not adhere to glass are quantitatively more capable of limiting the spread of influenza virus in cell culture than are glass-adhering cells. These results suggest that mice immunized with influenza virus have sensitized spleen cells that elaborate antibody to influenza virus, which can act locally to control the spread of infection.