Search

The natural world is full of odours—blends of volatile chemicals emitted by potential sources of food, social partners, predators, and pathogens. Animals rely heavily on these signals for survival and reproduction. Yet we remain remarkably ignorant of the composition of the chemical world. How many compounds do natural odours typically contain? How often are those compounds shared across stimuli? What are the best statistical strategies for discrimination? Answering these questions will deliver crucial insight into how brains can most efficiently encode olfactory information. Here, we undertake the first large-scale survey of vertebrate body odours, a set of stimuli relevant to blood-feeding arthropods. We quantitatively characterize the odour of 64 vertebrate species (mostly mammals), representing 29 families and 13 orders. We confirm that these stimuli are complex blends of relatively common, shared compounds and show that they are much less likely to contain unique components than are floral odours—a finding with implications for olfactory coding in blood feeders and floral visitors. We also find that vertebrate body odours carry little phylogenetic information, yet show consistency within a species. Human odour is especially unique, even compared to the odour of other great apes. Finally, we use our newfound understanding of odour-space statistics to make specific predictions about olfactory coding, which align with known features of mosquito olfactory systems. Our work provides one of the first quantitative descriptions of a natural odour space and demonstrates how understanding the statistics of sensory environments can provide novel insight into sensory coding and evolution.

Background Dental radiographs are essential tools for diagnosis. However, there are significant concerns about the dangerous effect of radiation especially on children. The aim of this study was to evaluate genotoxicity and cytotoxicity in the exfoliated cells of buccal mucosa of children subjected to Cone Beam Computed Tomography (CBCT). Methods The study included 18 healthy children aged (9–12 years) who were exposed to CBCT. All CBCT scans were performed with the i-CAT CBCT. Exfoliated buccal cells were scraped from the left and right cheek immediately before the exposure, after 10 ± 2 days, and after 1 month. Cells were stained using Feulgen/fast green stain and examined under light microscopy. Genotoxicity (Micronuclei) and cytotoxicity (condensed chromatin, karyorrhexis, pyknosis, and karyolysis) were scored. Statistical analysis was performed using the McNemar test, Wilcoxon Signed-Rank test, and Mann-Whitney U test at a significance level of p Results There were statistically significant differences in the mean percentages of micronuclei, condensed chromatin, karyorrhexis, pyknosis, and karyolysis before and 10 ± 2 days after the CBCT scan (p p > 0.05) except for karyolysis (p Conclusions CBCT may induce genotoxicity and cytotoxicity in buccal mucosa cells of children. Therefore, CBCT should not be prescribed unless necessary as it cannot be considered a risk-free procedure.

Study Objectives: The study aimed to evaluate the knowledge levels and opinions of athletes under 16 years of age about doping and ergogenic aids in different branches. The fact that there are no studies in the literature on the knowledge and opinions of athletes under the age of 16 on doping and ergogenic aids has encouraged us to the study. Methods: The sample of the study consists of 392 athletes under 16 years of age in different sports branches. In the study, a questionnaire consisting of 5 likert and 26 questions about doping substances and ergogenic aids was applied to the athletes by Eröz (2007). Results: As a result of the analysis of the obtained findings with the Chi-square test, it was determined that as the age of the athletes increased, the belief that the athlete used doping increased with the fear of losing. It has been determined that as the family income increases, the tendency to try every way to be successful does not decrease significantly, and athletes with low family income are more willing to try every way to be successful. As the education of the athlete's parents increased, the belief that the use of doping harmed the Fair-Play spirit in sports and that doping leads to unfair competition has been increased. Conclusion: The study revealed that there is a need to reinforce the doping knowledge of athletes. It has been concluded that certain socio-economic conditions are determinants in the use of doping by athletes and that they shape their tendency towards doping. Therefore, it is thought that the trainers, managers, athlete families and athletes about the negative effects of doping use on athlete health is of great importance.

Background: Providing restorations to anterior teeth in children is a challenging task due to the need for high esthetics, strength, and durability.Aim: this study was done to compare prefabricated primary zirconia with resin composite strip crowns on primary maxillary central and lateral incisors with regards to gingival health, plaque accumulation, recurrent caries, restoration failure, and opposing teeth wear over a period of 3, 6 and 12 months.Methods: Children attending the King Abdulaziz University, Faculty of Dentistry (KAUFD) clinics who needed restorations were screened for inclusion criteria. A total of 120 teeth were treated; 60 with zirconia and 60 with strip crowns. Randomization was done by simple random allocation using SPSS software version 20.0 (Armonk, NY; IBM Corp.). A simple descriptive statistic was used for analysis by Wilcoxon Signed-Rank test and Chi-square test. Level of significance was set at (α = 0.05) and level of confidence at (95%).Results: Zirconia crowns showed significantly less gingival bleeding at the 3- and 6-months follow up periods (ppppppConclusion: Based on our data we conclude that overtime teeth covered with zirconia crowns show better gingival health and less bleeding, plaque accumulation as well as less loss of material. On the other hand, zirconia can cause more loss of opposing tooth structure.Trial Registration: The presented research was registered retrospectively at ClinicalTrials.gov under registration number NCT03184012.

Background: Providing restorations to anterior teeth in children is a challenging task due to the need for high esthetics, strength, and durability. Aim: this study was done to compare prefabricated primary zirconia with resin composite strip crowns on primary maxillary central and lateral incisors with regards to gingival health, plaque accumulation, recurrent caries, restoration failure, and opposing teeth wear over a period of 3, 6 and 12 months. Methods: Children attending the King Abdulaziz University, Faculty of Dentistry (KAUFD) clinics who needed restorations were screened for inclusion criteria. A total of 120 teeth were treated; 60 with zirconia and 60 with strip crowns. Randomization was done by simple random allocation using SPSS software version 20.0 (Armonk, NY; IBM Corp.). A simple descriptive statistic was used for analysis by Wilcoxon Signed-Rank test and Chi-square test. Level of significance was set at (α = 0.05) and level of confidence at (95%). Results: Zirconia crowns showed significantly less gingival bleeding at the 3- and 6-months follow up periods (ppppppConclusion: Based on our data we conclude that overtime teeth covered with zirconia crowns show better gingival health and less bleeding, plaque accumulation as well as less loss of material. On the other hand, zirconia can cause more loss of opposing tooth structure. Trial Registration: The presented research was registered retrospectively at ClinicalTrials.gov under registration number NCT03184012.

Background Providing restorations to anterior teeth in children is a challenging task due to the need for high esthetics, strength, and durability. Aim this study was done to compare prefabricated primary zirconia with resin composite strip crowns on primary maxillary central and lateral incisors with regards to gingival health, plaque accumulation, recurrent caries, restoration failure, and opposing teeth wear over a period of 3, 6 and 12 months. Methods Children attending the King Abdulaziz University, Faculty of Dentistry (KAUFD) clinics who needed restorations were screened for inclusion criteria. A total of 120 teeth were treated; 60 with zirconia and 60 with strip crowns. Randomization was done by simple random allocation using SPSS software version 20.0 (Armonk, NY; IBM Corp.). A simple descriptive statistic was used for analysis by Wilcoxon Signed-Rank test and Chi-square test. Level of significance was set at (α = 0.05) and level of confidence at (95%). Results Zirconia crowns showed significantly less gingival bleeding at the 3- and 6-months follow up periods (p p p p p p

Background: Multiple mini interviews (MMI) is a structured student selection method where applicants rotate around a series of stations that do not require previously learned knowledge. The Big Five Inventory (BFI) is a tool often used to measure personality traits commonly used in applicant selection. Objective: The aim of the current study was to assess the effect of personality traits using the BFI on undergraduate dental students' performance in MMI. Methods: This research was conducted at The Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia. All undergraduates applying to the dental program at King Abdulaziz University, Faculty of Dentistry (KAUFD) in two academic years [(2014-2015) and (2015-2016)] undertook the MMI held at KAUFD and completed the BFI inventory with a total number of 350 students. The MMI consisted of five stations while the BFI contained forty-four items. Data were analysed by SPSS version 20, using independent-samples t-test, Mann- Whitney U test, Spearman’s rho correlation coefficient and Chi-square test. Results: female students scored higher than their male counterparts but scores were only significant in the empathy station (p

There is increasing interest in investigating the association between dental caries and childhood obesity, particularly among preschoolers where the evidence is limited. We aimed to measure the prevalence of obesity/overweight among preschool children aged 3 to 6 years, and to determine the relationship between obesity and dental caries in the primary dentition. A cross-sectional study was carried out in eight public and private preschools using a multi-stage stratified sample of 820 children. Waist circumference (WC) and body mass index (BMI) measurements were obtained. Caries was assessed using the National Institute of Dental Research’s decayed, missed or filled score (dmft). Based on BMI, 15% of children were obese and 10% were overweight. Based on WC, 13% of children were obese. The prevalence of obesity/overweight based on BMI was significantly higher among girls (p-value=0.014) and private preschools (p-value

Objectives: this study was aimed at comparing dental stress in children having their first dental visit to those returning for dental treatment using salivary biomarkers of stress including salivary cortisol (s-cortisol), Immunoglobulin-A (s-IgA) and alpha-amylase (s-α-amylase). Additionally, the study was aimed at monitoring the change in stress in new patients as they progressed from the waiting to the clinical areas. Study design: salivary samples were collected from 40 children who had not been to a dentist before and similar samples were collected from 40 children who were returning for completion of dental treatment. Salivary cortisol, s-IgA and s-α-amylase concentrations were obtained by Enzyme-linked Immunosorbent Assay (ELISA). Results: salivary cortisol levels were higher for new patients at the waiting area compared to that at the dental chair (p=0.05). Salivary alpha-amylase significantly increased in new patients while being seated in the dental chair. Returning patients had higher s-α-amylase (p=0.001) and s-IgA (p=0.016) compared to new patients. Returning patients had the lowest level of s-cortisol when providers were faculty pediatric dentists than with students and interns (p=0.035). Conclusions: children coming in for their first dental visit may experience dental stress at the waiting area before being seated for dental examination. Returning children may experience higher levels of stress compared to new child patients possibly due to previous dental exposure.

Prior research has shown that students' previous grade point average (GPA) is the best predictor for future academic success. However, it can only partly predict the variability in dental school performance. The aim of this study was to assess the predictive value of multiple mini-interviews (MMI) as an admission criterion by comparing them with the academic performance of dental students over a two-year period. All incoming undergraduate dental students at the King Abdulaziz University Faculty of Dentistry (KAUFD) during academic year 2013-14 were invited to participate in MMI. Students rotated through six objective structured clinical exam (OSCE)-like stations for 30 minutes total and were interviewed by two trained faculty interviewers at each station. The stations were focused on noncognitive skills thought to be essential to academic performance at KAUFD. The academic performance of these students was then followed for two years and linked to their MMI scores. A total of 146 students (71 males and 75 females) participated in an interview (response rate=92.9%). Most students scored in the acceptable range at each MMI station. Students' total MMI score, ambitions, and motives were significant predictors of GPA during the two years of follow-up (p

Erdogan, Ozgur/0000-0003-1547-2513 WOS: 000460891100010 PubMed: 30837422 Objective: Irrigation with saline is one of the essential methods for reducing the heat generated during dental implant osteotomy. High irrigation volume impairs visibility of the surgical field, thus complicates the surgery. In this study, we aimed to determine the optimal irrigation volume for heat reduction during dental implant drilling. Materials and Methods: Thirty-two implant osteotomies were prepared on four fresh cow ribs. Heat generated during the final implant drilling was measured both with infrared thermography and thermocouple method. Initial and maximum temperatures were measured at four different irrigation volumes; 32, 44, 56, and 68 ml/min. Results: Both measurement methods showed that the amount of temperature rise is associated with the irrigation volume during implant drilling. There is no further decrease in temperature rise above irrigation volume of 56 ml/min. Conclusion: Saline irrigation with 56 ml/min provides sufficient heat reduction during dental implant drilling and higher irrigation volumes are not necessary.

This study examined the validity evidence of noncognitive skills of incoming students in the Faculty of Dentistry at King Abdulaziz University using multiple mini-interviews (MMI). Validity evidence in response process, internal structure and relationship to other variables was investigated.A total of 146 students were interviewed by faculty members over a two-day period. The interviews took the form of an MMI, which consisted of six objective structure clinical examination (OSCE) stations with two faculty interviewers per station. Each student rotated through the six stations and were asked 4-5 structured questions per station. Each student was rated on a three-point rating scale.The majority of dental students were rated to be acceptable. The inter-rater reliability was 0.91 which was significantly high (range: 0.87-0.94). The total MMI score for all stations was 73.47 (SD = 8.49) with female students scoring significantly higher than males did (p 0.001). Generalizability study results indicated good reliability (Φ-coefficient = 0.73; G-coefficient = 0.75). Moderate association was found between total MMI score and foundation year GPA (r = 0.30, p ≤ 0.001).Preliminary validity evidence supports the use of MMI scores as an admission tool for dental students, with respect to its response process, internal structure and relationship to other variables.

Objective: To assess the parents' perception of the oral health-related quality of life (OHRQOL) in children with Cerebral Palsy (CP) and compare it with normally developing children. Study Design: 63 children with CP were recruited from 8 disability centers, and 99 healthy controls were recruited from 5 elementary schools. The ages of the children in both groups were from 6-12 years. The Franciscan Hospital for Children Oral Health-Related Quality of Life (FHC-OHRQOL) was used to measure the OHRQOL and an oral examination was conducted in the schools/centers of the children to assess the teeth, gingival health, and oral hygiene. Results: The FHC-OHRQOL showed a significant difference in 3 out of 4 sections indicating lower OHRQOL in the CP group. The examination showed no significant difference in the dental and gingival health and in the level of oral hygiene. Conclusion: The OHRQOL of children with CP is significantly lower than that of normally developing children although the oral health status of children with CP is not significantly different from that of normally developing children.

Prior research has shown that students' previous grade point average (GPA) is the best predictor for future academic success. However, it can only partly predict the variability in dental school performance. The aim of this study was to assess the predictive value of multiple mini-interviews (MMI) as an admission criterion by comparing them with the academic performance of dental students over a two-year period. All incoming undergraduate dental students at the King Abdulaziz University Faculty of Dentistry (KAUFD) during academic year 2013-14 were invited to participate in MMI. Students rotated through six objective structured clinical exam (OSCE)-like stations for 30 minutes total and were interviewed by two trained faculty interviewers at each station. The stations were focused on noncognitive skills thought to be essential to academic performance at KAUFD. The academic performance of these students was then followed for two years and linked to their MMI scores. A total of 146 students (71 males and 75 females) participated in an interview (response rate=92.9%). Most students scored in the acceptable range at each MMI station. Students' total MMI score, ambitions, and motives were significant predictors of GPA during the two years of follow-up (p0.038 and p0.001, respectively). In this study, MMI was found to be able to predict future academic performance of undergraduate dental students.

Immobilized photocatalysts are preferred over suspended catalyst particles in slurry reactors due to elimination of filtration process. The requisite condition for their use is themechanical and chemical stability under flow conditions. The stability of TiO2 coated ZnO nanorods (TiO2/ZnO) immobilized at the bottom of a prototype continuous-flow reactor designed in the form of a rectangular channel is investigated under continuous flow conditions in this work. Morphology and structure of the nanorod arrays are characterized by field emission scanning electron microscopy and X-ray diffraction. Optical properties of the rods are determined by UV-Vis spectroscopy measurements. Dissolution trends of zinc ions from the TiO2/ZnO rods are determined under dark, UV radiation and photodegradation conditions, and compared with the results of uncoated ZnO. The effect of the number of TiO2 film coatings and the calcination time of the spin-coated films are investigated as parameters. Coating of the ZnO nanorods with TiO2 has greatly reduced its dissolution under UV radiation to a level less than the dissolution of uncoated ZnO rods in complete darkness. Photocatalysis under UV radiation was found to increase the dissolution rate of zinc ions. This increase was attributed to cavity or pit formation on the upper surfaces of nanorods. TiO2 coating was found to decrease the dissolution rate significantly by reducing the extent of pit formation. TiO2 was also found to increase the catalytic effectiveness of ZnO nanorod film in the photodegradation of methyl orange dye selected as a model organic pollutant. (C) 2015 Elsevier B.V. All rights reserved.

Objectives: To investigate the prevalence of obesity among elementary school children and to examine the association between obesity and caries activity in the mixed dentition stage. Methods: This cross-sectional study was conducted in King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia between September 2014 and June 2015 using a multi-stage stratified sample of 915 elementary school children (482 boys, 433 girls) in Jeddah, Saudi Arabia. Anthropometric measurements, consisting of height, weight, body mass index (BMI), and waist circumference (WC), were obtained. Children were classified as underweight/healthy, overweight, or obese and as non-obese or obese according to their BMI and WC, respectively. Each child’s caries experience was assessed using the decay score in the primary and permanent teeth. Results: Based on BMI, 18% of children were obese, 18% were overweight, and 64% were underweight/normal. Based on WC, 16% of children were obese, and 84% were non-obese. Girls had a significantly higher prevalence of obesity based on WC measurements ( p less than 0.001), but not BMI. Children enrolled in private schools had a significantly higher prevalence of obesity ( p less than 0.05) than those in public schools. For primary and permanent teeth combined, children with higher BMI and WC had a lower prevalence of caries ( p less than 0.05). Conclusion: The prevalence of obesity was high among male and female elementary school children. Overall caries activity was inversely proportional to BMI and WC. Saudi Med J 2016; Vol. 37 (12): 1387-1394 doi: 10.15537/smj.2016.12.15904

Aim: This review explores the discriminating factors involved for increased caries experience in asthmatic children. Background: Dental caries is the single most common chronic disease of childhood. Children with chronic medical conditions are considered high caries risk. Asthma is one of the most common chronic medical conditions in childhood. Material: 27 studies examined the asthma-caries causative relationship. Most of them were cross sectional studies; only 5 longitudinal studies were reported. In the literature, there is a lack of consensus regarding the relationship between dental caries and asthma in a child population.Conclusion: Despite the fact that some relatively recent studies have provided little evidence for an asthmacaries causative relationship, the majority and the most recent reports have concluded that the individualistic nature of asthmatic condition, through either its disease status or its pharmacotherapy (different combinations of medicaments), or attempts to alleviate the condition's physiologic sequelea, carries several factors for an increased caries risk.