563 research outputs found
The Δρομοδείχτης της Ελλάδος of 1824 and Athanasios Stageirites (Τίτλος περίληψης)
No full textσ. [281]-290Κείμενο στα ελληνικά με περίληψη στα αγγλικά με τον τίτλο: The Δρομοδείχτης της Ελλάδος of 1824 and Athanasios StageiritesThe article first examines the close relationship between the publication “Δρομοδείχτης της Ελλάδος” [1824] and the publication “Ηπειρωτικά” (1819) by Athanasios Stageirites and then suggests that Athanasios Stageirites is the likeliest author of the “Δρομοδείχτης της Ελλάδος”.Δωδώνη: Τεύχος Πρώτο: επιστημονική επετηρίδα του Τμήματος Ιστορίας και Αρχαιολογίας της Φιλοσοφικής Σχολής του Πανεπιστημίου Ιωαννίνων; Τόμ. 43-44 (2014-2015
Influence of parental socioeconomic characteristics on children’s dietary and oral health habits
No full textThe aim of this study was to investigate the relationship between parent’s socioeconomic status including age, income, marital status, parent’s education level, and whether they stay at home and the influence of these factors on their children’s dietary habits and oral health. A total of 60 parents of children aged 1-5-years were included in this questionnaire-based study. Parents were asked to complete a self-administered paper–pencil questionnaire that included 53 items assessing different factors such as their demographic information and their children’s dietary and oral health factors. Demographic information included the parent’s age, income level, marital status, parents’ education level, and if the parents are stay at home parents. Although parents’ age, marital status, income and employment status showed no significant relationship with children’s eating schedule (p>0.05), parents’ education level and whether they stay at home significantly impacted children’s eating schedule (p<0.001 and p=0.02 respectively). Most of the parental characteristics did not significantly impact the consumption of juice and sugar except for parents’ education level. Sugar consumption was inversely related to parents’ education level (p=0.02). When comparing the prevalence of dental caries in the three categories of parents’ education level, children of parents with a bachelor’s degree or higher reported significantly lower prevalence of dental caries among their children than parents from other educational levels(p=0.005). The parental demographical factors showed no influence on whether the child drank from a bottle or sippy cup for children older than 1-year-old. Also, parents’ income did not have a significantly impact on children’s eating habits and the level of caries. In conclusion, our results suggest a possible association between dental caries and selected parental sociodemographic characteristics. Parent’s education level had a significantly positive impact on the eating schedule of their children as well as children’s sugar consumption. Having stay at home parents can positively and significantly impact on adopting a healthy eating schedule among children
Correlation between dental classification and upper airway measurements using acoustic rhinometry and pharyngometry
No full textPURPOSE: To determine the prevalence of Sleep Disturbances (SD) in children and to evaluate the correlation between dental classification and airway dimensions.
METHODS: Children between 3 – 18 years at the Boston University Pediatric Oral Healthcare Center in Boston, Massachusetts were recruited for this study. Based on parents’ responses in a brief sleep-screening questionnaire, cases were identified as children with SD and controls were those without. Another detailed questionnaire was used to collect information on demographics and sleep patterns. Clinical and upper airway examinations were conducted using Eccovision Acoustic Rhinometer (AR) and Acoustic Pharyngometer (AP). Statistical differences in upper airway measurements by type of dental occlusion were evaluated.
RESULTS: Among 281 children, the prevalence of SD was 38%. Upper airway measurements among 176 participants using AP showed significantly higher pharyngeal Minimum Cross-Sectional Area (MCA) for class III dental occlusion compared to class I (P=.036) in children with SD. Statistically significant differences in MCA, Airway Volume (AV), and minimum distance to MCA by type of dental occlusion were mainly observed among children with SD (P<.05).
CONCLUSIONS: The results highlight a possible correlation between nasal and pharyngeal airway dimensions and dental classification among children with SD. Further analysis that include radiological examinations may help in confirming these findings
Exploring the role of teledentistry in providing dental care
No full textSTUDY AIMS:
The overall aim of this project was to evaluate the dental care services provided through teledentistry and to evaluate the methods used to diagnose and manage patients’ concerns during the televisits.
STUDY DESIGN:
This study was a retrospective chart review and included patients who completed televisits between March 1st, 2020, to January 31st, 2021, at the Boston Medical Center (BMC). Information on a total of 323 patients was obtained from EPIC, the electronic patient record system. These patients completed televisits in both the Departments of Pediatric Dentistry and Oral and Maxillofacial Surgery at BMC. For each televisit, we gathered information from the televisit workflow form which includes detailed information on the patient’s visit. The level of accuracy of diagnosis and details on the management of the diagnosed condition during the televisit was compared to the diagnosis and management completed during the in-clinic visit. Differences in the level of accuracy by patients’ characteristics were analyzed. Other factors correlated with the level of accuracy were also evaluated using univariate and multivariate analysis. All statistical tests were conducted using SPSS statistical software.
RESULTS:
Overall, almost half of the study population (49.2%) presented to the televisit with the chief complaint of pain. The majority of the televisits, 99.1%, were completed by phone and only 13% of the patients’ charts included photos. In terms of management, 49.8% of the cases were managed conservatively during the televisits and 57.9% were advised to follow-up to the clinic for dental treatment and among these patients about 78% returned to the clinics at BMC. Accuracy of diagnosis was found to be 72.4% when comparing the diagnosis made during the televisits to the clinical diagnosis. The level of accuracy was significantly associated with the type of management that was provided to the patients during the televisits (p-value=0.008).
CONCLUSION:
Teledentistry can be used as a successful module in providing the optimum patient care especially where the in-clinic visit cannot be achieved due to geographical or financial barriers, or due to lack of access. It is also a valuable mode of communication with patients in severe emergency situations such as the recent COVID pandemic.2023-08-03T00:00:00
Synthesis, structure and reactivity of ligand stabilized coinage metal nanoclusters
No full text© 2013 Athanasios ZavrasPublications included in thesis:Zavras, A., Khairallah, G. N. & O’Hair, R. A. J. (2013). Bis(diphenylphosphino)methane ligated gold cluster cations: synthesis and gas-phase unimolecular reactivity. International Journal of Mass Spectrometry, 354-355, 242-248. DOI: 10.1016/j.ijms.2013.05.034Zavras, A., Khairallah, G. N., Connell, T. U., White, J. M., Edwards, A. J., Donnelly, P. S. & O'Hair, R. A. J. (2013). Synthesis, structure and gas-phase reactivity of a silver hydride complex [Ag3{(PPh2)2CH2}v3(μ3-H)(μ3-Cl)]BF4. Angewandte Chemie International Edition, 52(32), 8391-8394. DOI: 10.1002/anie.201302436Zavras, A., Khairallah, G. N., Connell, T. U., White, J. M., Edwards, A. J., Donnelly, P. S. & O'Hair, R. A. J. (2014). Synthesis, structural characterization and reactivity of a silver hydride nanocluster [Ag3{(PPh2)2CH2}3(μ3-H/D)](BF4)2: a “Venus fly trap” for chloride. Chemical Science, (submitted).The coinage metal nanoclusters (CMNCs), defined as copper, silver or gold, constitute an intermediate state of matter that exist between molecules and bulk material. The properties of CMNCs differs to that of molecules and bulk material due to quantum confinement effects. These nanostructured materials have attracted significant attention owing to their fundamentally interesting architectures, and unique properties with applications in areas such as catalysis, optical materials, medical imaging, models for hydrogen storage. Tailoring the properties of such promising materials has proven challenging and requires a fundamental understanding of their assembly, structure and reactivity.
The aim of this thesis is: (i) the primary application of mass spectrometric techniques to monitor the formation of CMNCs which result from the addition of sodium borohydride to a solution consisting of a coinage metal salt and the bidentate ligand, bis(diphenylphsphino)methane (dppm) under various synthetic conditions; (ii) to apply this information in developing synthetic approaches to optimize clusters of interest and apply a mass spectrometry (MS) directed synthesis leading to the isolation of crystalline material suitable for structural characterization by X-ray crystallography (iii) apply MS based analysis methods to provide information on the reactivity of CMNCs in solution and the reactivity and structure of mass selected CMNCs in the gas phase.
Electrospray ionization mass spectrometry (ESI-MS) and UV-Vis spectroscopy were used to monitor the formation of gold nanocluster cations in the condensed phase via the sodium borohydride (NaBH4) reduction of methanolic solutions containing AuClPPh3 and dppm. ESI-MS highlights the formation of complexes prior to the addition of NaBH4 as [Au2(dppm)2]2+, [Au(PPh3)2]+, [Au2(dppm)3]2+, [Au(dppm)2]+,[Au2Cl(dppm)2]+. The cationic complex product distribution can be monitored over a range of metal to ligand ratios to minimize the colloid precursor [Au(PPh3)2]+. The addition of NaBH4 where the optimized metal to ligand ratio was determined as AuClPPh3:dppm is 1:2 results in the formation of the following types of gold nanoclusters [Au9(dppm)4]3+, [Au9(dppm)5]3+, [Au5(dppm)3(dppm-H+)]2+, [Au10(dppm)4]2+, [Au11(dppm)5]3+, [Au11(dppm)6]3+, [Au13(dppm)6]3+ and [Au14(dppm)6(Ph2PCHPPh2)]3+. The gas phase unimolecular chemistry of these cations was examined by (i) collision induced dissociation (CID) and electron capture dissociation resulting in the gas phase synthesis of the novel clusters [Aux(dppm)y]z+ (x = 2,3 , 6–13; y = 1–6 and z = 1–3) and [Aux(dppm)y(dppm-H+)]z+ (x = 5,14; y= 2,5; z = 2,3) via ligand loss and core fission fragmentation channels. (ii) electron capture dissociation (ECD) of mass selected multiply charged gold cluster cations where an additional fragmentation channel arises due to C-P bond activation.
ESI-MS was also applied to study the reactivity that results from silver salts in the presence of dppm, that are treated with sodium borohydride. It was observed by ESI-MS that no all metallic silver clusters had formed. Instead there existed abundant and relatively monodisperse trinuclear silver(I) hydride clusters. The synthesis could be refined by careful MS based analysis to result in the isolation of crystalline material of (i) [Ag3(μ3-H)(μ3-Cl)(dppm)3]BF4, and (ii) [Ag3(μ3-H)(dppm)3](BF4)2. These clusters could be mass selected to generate novel gas phase clusters in the gas phase. The multiply charged cation [Ag3(μ3-H)(dppm)3]2+ was also investigated by ECD and EID.
The silver hydride cluster cation [Ag10H8(dppm)6]2+ was observed during the synthesis of trinuclear silver clusters. This cluster has yet to be isolated
Coinage metal hydrides: reactive intermediates in catalysis and significance to nanoparticle synthesis
No full text© 2019 Dr. Athanasios ZavrasThe coinage metal hydrides of copper, silver and gold have applications in catalysis and nanoparticle synthesis. Coinage metal hydrides are key intermediates in the chemical transformations of a range of substrates including fine chemical syntheses and chemical storage of hydrogen. Ranging from mononuclear coinage metal hydrides to clusters and
nanoparticles, a fundamental understanding of their atomic and molecular interactions is invaluable in developing innovative solutions to practical problems. The reactive sites can be identified using a range of spectroscopic methods allowing the “tuning” and/or “reshaping” of the reactive site by ligands to control the reactivity. Mass spectrometry provides a means to identify coinage metal hydrides in solution and further allows isolation of discrete coinage metal hydrides that can be: (i) characterised, for example by spectroscopic methods, (ii) reacted with neutral substrates, or (iii) fragmented to generate reactive intermediates in the gas phase.
The use of borohydride in nanoparticle synthesis is well-known. Chapter 2 describes a mass spectrometry directed synthesis to afford the first isolable silver hydride borohydride cluster, [Ag3(μ3-H)(μ3-BH4)L3]BF4 (L =bis(diphenylphosphino)methane), structurally characterised by X-ray crystallography. Gas-phase experiments and DFT calculations reveal ligand (L) loss from [Ag3(H)(BH4)L3]+ results in the loss of BH3 and a geometry change of the cluster to yield [Ag3(H)(BH4)Ln]+ (n = 1 or 2). This work reveals links between silver hydride/borohydride and silver hydride nanoclusters adding to our understanding of silver nanoparticle synthesis using borohydride salts.
Chapter 3 examines that the reactivity of CO2 with the binuclear silver hydride cation core, [Ag2H]+, can be controlled by design. Reshaping the geometry and reaction environment of [Ag2H]+ using a range of phosphine ligands (bis(diphenylphosphino)methane, 1,2- bis(diphenylphosphino)benzene and bis(diphenylphosphino)ethane) allows “tuning” of the active site’s reactivity toward formic acid to produce H2. Gas-phase ion-molecule reactions, collision-induced dissociation, infrared and ultraviolet action spectroscopy and computational chemistry link structure to reactivity and mechanism. The gas-phase studies were then translated to solution-phase studies using NMR to show that H2 could be produced from solutions comprising well-defined ratios of ligand, AgBF4, NaO2CH and HO2CH at near ambient temperature.
Chapter 4 further developed the concept of altering the reactive site by changing the binuclear metal centres of the [LAg2H]+ core to compare all six possible combinations of copper silver and gold i.e. [LAg2H]+, [LCu2H]+, [LAu2H]+, [LCuAgH]+, [LCuAuH]+ and [LAgAuH]+ in the gas phase. DFT calculations, gas-phase ion-molecule reactions and gas-phase energy-resolved collision-induced dissociation showed both metal centres play a role in the reaction with formic acid. One metal site functions as an “anchor” for an oxygen of formic acid or formate while the other facilitates the dehydrogenation step resulting in the formation of H2. It was found that the copper homobinuclear species performed best overall.
Attempts to isolate the reactive intermediate [LAg2(O2CH)]+ by using a range of bisphosphine ligands resulted in the isolation of an unusual co-crystal in the case of L = dcpm as described in Chapter 5. Single crystal X-ray diffraction of crystals suitable for crystallographic analysis revealed two discrete tetranuclear silver clusters [(μ2-dcpm)Ag2(μ2-O2CH)(η2-NO3)]2·[(μ2- dcpm)2Ag4(μ2-NO3)4]. The solution-phase studies, tracked by NMR, show that H2 could be produced from solutions comprising well-defined ratios of ligand, AgBF4, NaO2CH and HO2CH at 65⁰C. Gas-phase studies indicate that while the tetranuclear cluster [L2Ag4(O2CH)3]+ undergoes sequential decarboxylation reactions, none of the resultant hydrides react with formic acid. These results highlight important role of the binuclear hydride [LAg2(H)]+ in the catalytic decarboxylation of formic acid.
Hydrido cuprate [CuH2]- has been explored for its applications in hydrogen storage. Chapter 6 indicates two chemically induced routes for the liberation of hydrogen when [CuH2]- is reacted with various chemical substrates. One path occurs via homocoupling of both hydride ligands giving the substrate-coordinated copper, the other by protonation with acids
Transforming inter-professional dental care: evaluation of a team-based pediatric dental clinic
No full textINTRODUCTION: Despite improvements in prevention, treatment modalities, and access of dental care, dental caries is considered one of the most common diseases among children worldwide. Significant disparities in the prevalence of dental caries and other oral health problems continues to exist by race ethnic groups and by socio-economic status. Another factor that influences the prevalence is the physical and mental status of children; this is attributed to the limitation of awareness, dexterity, and access to care among children with special health care needs. Overall improving the access to care, incorporating team-based practice and interprofessional collaboration are vital to improve and maintain oral and systemic health among children.
OBJECTIVE: The objective of this study is to assess the team-based practice in the Pediatric Oral Healthcare Center (POHC) at Boston University School of Dental Medicine.
MATERIALS AND METHODS: Different parameters were evaluated including dental procedures and patients’ outcomes; screening by non-dental specialists; feasibility and sustainability of team-clinics; retreatment of dental procedures within two years of follow-up; health care providers’ and administrative perception towards interprofessional collaboration.
RESULTS: Children with special healthcare needs represented 13% of the total patients, with the majority under 6 and over 12 years old between 2017-2019. Sixty-five patients were evaluated by a Speech and Language Pathologist (SLP) and 42 were referred for further evaluation. The RDN evaluated 172 children with 50 children having abnormal BMI, and the majority were overweight or obese. Multidisciplinary treatment approach involving SLP and RDN in a pediatric dental clinic can provide an overall net revenue as high as $25,681.20 monthly. During follow-up, only 9% of the cases required retreatment; age was a significant factor with older children being less likely to require retreatment. High levels of satisfaction towards interprofessional collaboration was reported among pediatric dentists, pediatricians, SLPs, RDN and administrative staff.
CONCLUSION: Team-based pediatric dental clinic can be feasible and financially beneficial. Thus, a pediatric wellness care center that integrates general and dental care services through an interprofessional collaboration can play a vital role in significantly improving children’s oral and systemic health.2022-07-29T00:00:00
Dataset in support of the Southampton doctoral thesis 'The boatbuilding tradition of the Aegean during the Late Neolithic – Early Bronze Age periods. Typological classification, digital reconstruction and seakeeping assessment'
No full textDataset in support of the Southampton doctoral thesis 'The boatbuilding tradition of the Aegean during the Late Neolithic – Early Bronze Age periods. Typological classification, digital reconstruction and seakeeping assessment' Appendix D - Resistance data and Appendix C - Stability data.
This dataset is focused on two appendices:
Appendix D - Resistance data. D.1 Resistance data produced by the author via MAXSURF Resistance for this thesis.
Appendix C - Stability data
C1. Stability data – STIX and ISO criteria, produced by the author via MAXSURF Stability software for his thesis
This research was funded by Southampton Marine and Maritime Institute (SMMI), Vice-Chancellor's Scholarship, Greek Archaeological Committee UK (GACUK)
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Gas-phase reactions of the rhenium oxide anions, [ReOx]- (x = 2 - 4) with the neutral organic substrates methane, ethene, methanol and acetic acid
No full textThe ion–molecule reactions of the rhenium oxide anions, [ReOx]– (x = 2–4) with the organic substrates methane, ethene, methanol, and acetic acid have been examined in a linear ion trap mass spectrometer. The only reactivity observed was between [ReO2]– and acetic acid. Isotope-labelled experiments and high-resolution mass spectrometry measurements were used to assign the formulas of the ionic products. Collision-induced dissociation and ion–molecule reactions with acetic acid were used to probe the structures of the mass-selected primary product ions. Density functional theory calculations [PBE0/LanL2DZ6-311+G(d)] were used to suggest possible structures. The three primary product channels observed are likely to arise from the formation of the metallalactone [ReO2(CH2CO2)]– (m/z 277) and H2, [CH3ReO2(OH)]– (m/z 251) and CO, and [ReO3]– (m/z 235), H2 and CH2CO
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