Superlubricity and Stress-Shielding of Graphene Enables Ultra Scratch-Resistant Glasses

Glasses, when subjected to scratch loading, incur damages affecting their optical and mechanical integrity. Here, it is demonstrated that silica glasses protected with mechanically exfoliated few-layer graphene sheets can exhibit remarkable improvement in scratch resistance. To this extent, the friction and wear characteristics of silica glasses with exfoliated graphene using atomic force microscopy (AFM) are explored. The friction forces recorded during AFM scratch tests of the graphene-glass surfaces at multiple loads exhibit ∼98% reduction compared to that of the bare silica glass, with the friction coefficient falling in the superlubricity regime. This dramatic reduction in friction achieved by the graphene sheets results in significantly lower wear of the graphene-glass surfaces postscratching. Further investigations employing atomistic simulations reveal that the stress-shielding mechanism is due to the reduced deformation of graphene-glass surfaces, thereby curtailing the overall damage. Altogether, the present work provides a new fillip toward the development of glasses with enhanced scratch resistance exploiting two-dimensional coatings.

Incorporating ion-specific van der Waals and soft repulsive interactions in the Poisson-Boltzmann theory of electrical double layers

Electrical double layers (EDLs) arise when an electrolyte is in contact with a charged surface, and are encountered in several application areas including batteries, supercapacitors, electrocatalytic reactors, and colloids. Over the last century, the development of Poisson-Boltzmann (PB) models and their modified versions have provided significant physical insight into the structure and dynamics of the EDL. Incorporation of physics such as finite-ion-size effects, dielectric decrement, and ion-ion correlations has made such models increasingly accurate when compared to more computationally expensive approaches such as molecular simulations and classical density functional theory. However, a prominent knowledge gap has been the exclusion of van der Waals (vdW) and soft repulsive interactions in modified PB models. Although short-ranged as compared to electrostatic interactions, we show here that vdW and soft repulsive interactions can play an important role in determining the structure of the EDL via the formation of a Stern layer and in modulating the differential capacitance of an electrode in an electrolyte. To this end, we incorporate ion-ion and wall-ion vdW attraction and soft repulsion via a 12-6 Lennard-Jones (LJ) potential, resulting in a modified PB-LJ approach. The wall-ion LJ interactions were found to have a significant effect on the electrical potential and concentration profiles, especially close to the wall. However, ion-ion LJ interactions do not affect the EDL structure at low bulk ion concentrations (<1 M). We also derive dimensionless numbers to quantify the impact of ion-ion and wall-ion LJ interactions on the EDL. Furthermore, in the pursuit of capturing ion-specific effects, we apply our model by considering various ions such as Na, K+, Mg2+, Cl-, and SO42-. We observe how varying parameters such as the electrolyte concentration and electrode potential affect the structure of the EDL due to the competition between ion-specific LJ and electrostatic interactions. Lastly, we show that the inclusion of vdW and soft repulsion interactions, as well as hydration effects, leads to a better qualitative agreement of the PB models with experimental double-layer differential capacitance data. Overall, the modified PB-LJ approach presented herein will lead to more accurate theoretical descriptions of EDLs in various application areas.

Using a machine learning algorithm to detect depressed ejection fraction from a single-lead ECG

Background

Multiple studies demonstrate the benefit of intervention for left ventricular ejection fraction (LVEF) below 40%, so the development of a low ejection fraction algorithm to detect LVEF below 40% can aid in early screening of initial asymptomatic Heart Failure with reduced Ejection Fraction (HFrEF).

Objective

To demonstrate the performance of a low ejection fraction algorithm using single-lead ECG data to detect LVEF below 40%.

Methods

We collected 1325 single-lead ECG recordings (15s duration) at various chest positions using an electronic stethoscope from 197 patients. We analyzed these ECG recordings using a deep neural network model trained on individual leads extracted from a 12-lead ECG to discriminate left ventricular ejection fractions (EFs) above or below different thresholds. We compared the model output to ejection fraction measured using echocardiograms.

Results

Across all recordings from all patients, we obtained an AUROC of 0.89, with a sensitivity of 88% and specificity of 74% using a model output threshold of 0.35 (Figure 1). The AUROC of recordings taken at different orientations and stances ranged from 0.85 to 0.92 (Table 1), with a sensitivity of at least 78% and specificity of at least 66% at any orientation.

Conclusion

Using a single lead ECG measured by an electronic stethoscope and a deep neural network model, we were able to detect depressed ejection fraction (≤40%) with a sensitivity of 88% and specificity of 74%. This work demonstrates the utility of a low-cost electronic stethoscope and machine learning for early screening and detection of depressed left ventricular ejection fraction.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Eko Health

Comparison and Evaluation of Attitude and Knowledge Towards the Management of Dental Injury in School Teachers Before and After Oral Health Education

Background

Dental traumatic injuries are prevalent in school-going children. Therefore, It is critical to ascertain the knowledge and practices of school teachers who are in close contact with these children.

Aim

To evaluate the knowledge and attitude of school teachers toward dental trauma and the effect of the educational intervention.

Materials and methods

The interventional study was designed by two-stage cluster sampling. A total of 158 teachers were part of the research. Data was collected through a pretested questionnaire. Re-evaluation was done after an informative lecture. Results were statistically analyzed.

Result

The knowledge was consistently lacking prior to intervention with the level of correct answer ranging from 0.6 to 56.3%. It improved significantly post education ranging up to 96.6%. A positive attitude was noticed even before the intervention was employed.

Conclusion

Study observes a significant knowledge gap regarding the primary management of dental injuries amongst school teachers and emphasizes the need for urgent educational intervention to fill in this gap.

Clinical significance

Suggestions derived from this study are especially important in today’s scenario where, the concept of conservation, retention, prevention and early intervention of tooth structures is topmost of all the priorities.

How to cite this article: Nashine N, Bansal A, Tyagi P, Jain M, Jain A, Tiwari U. Comparison and Evaluation of Attitude and Knowledge towards the Management of Dental Injury in School Teachers Before and After Oral Health Education. Int J Clin Pediatr Dent. 2018;11(5):425-429.

Hospital Based Study of Poisoning Among Children, 1 to 18 Years of Age in Eastern Nepal

IntroductionThe poisoning among children had been a major cause of hospital admission and also a significant global health problem throughout the world including Nepal. There are various studies suggestive of incidence rate of poisoning in children ranging from 0.74% to 3%. In older children, poisoning is usually intentional where as in infants and younger children it is accidental in nature There are few studies done in Nepal and they are mainly from Kathmandu valley, this study will add more information from eastern region of Nepal.ObjectiveThis study aimed to find out the type of poisoning among children and adolescents, manner of poisoning and its outcomes.MethodologyThis was a retrospective study carried out at Nobel Medical College Teaching Hospital over a period of one year starting from  1st  August 2014 to 31 July 2015. This study included all the children and adolescents of 1 to 18 years of age admitted to pediatric ward and ICU for the management of poisoning. The information including name of poisons, manner of poisoning, socio-economic and demographic factors related to poisoning, geographical distribution of sample population, durations of hospital stay and outcome of treatment were retrieved from the records. The data was analyzed using SPSS. Susceptibility, urinary tract infection, uropathogens.ResultsA total of 64 cases were studied. It included almost the same number of males (n=31) and females (n=33). The age group of 13-18 years had the largest prevalence of poisoning (n=22). Organo-phosphorus (n=25) was the commonest poison. As the study was conducted in a tertiary care center of eastern Nepal located at Biratnagar, Morang district, a majority of the cases (39) were from Morang. A total of 41% children required hospital stay for more than 7 days where as 37% of them required 5-7 days of hospital stay and only 22% children stayed for 1-4 days in the hospital. No mortality was noted.ConclusionThe pediatric poisoning in eastern Nepal is a significant public health issue and nature of poisoning was accidental followed by suicidal. The commonest age group involved is adolescence, which highlights the need for education and implementation of suicidal prevention programming this region. The higher prevalence of accidental poisoning in first two year of life necessitates the need of child safety and injury prevention program in the community.  Birat Journal of Health Sciences Vol.2/No.1/Issue 2/ Jan - April 2017, Page: 138-141

Eruption Chronology in Children: A Cross-sectional Study

Aims and objectives

The purpose of this study is to determine the appropriate reference standard for eruption timing of primary teeth in infants and preschool children of Bhopal city and to determine the role of various factors affecting the eruption of primary dentition.

Materials and methods

A cross-sectional study was conducted among the infants and preschool children (4-36 months) attending the local government or private hospitals, and vaccination centers. Prior to the study, Institutional Ethical Committee clearance and informed written consent from the parents were obtained. The data were collected from full-term infants and preschool children of 4 to 36 months from Bhopal city. Oral examination was done under adequate natural light by a single examiner using mouth mirror and probe. Teeth present in the oral cavity were noted by using Federation Dentaire Internationale system of nomenclature in the preformed pro-forma. The teeth were considered as erupted, when any part of its crown had penetrated the gingiva and was visible in the oral cavity. Height, weight, birth weight, and other close-ended questions in questionnaire were asked from parents.

Results and conclusion

The data collected were statistically analyzed and it was observed that significant relation exists between tooth eruption and birth weight, feeding habits, socioeconomic status, and body mass index (BMI). Based on the findings, it may be concluded that Indian children experienced delayed eruption of primary teeth when compared with children of different countries and standard norms.

How to cite this article

Verma N, Bansal A, Tyagi P, Jain A, Tiwari U, Gupta R. Eruption Chronology in Children: A Cross-sectional Study. Int J Clin Pediatr Dent 2017;10(3):278-282.

Erosive effects of pediatric liquid medicinal syrups on primary enamel: An in vitro comparative study

Context:

The use of liquid medicinal syrups in childhood is high owing to the reasons that children suffer from illness quite often. The acidic component in the formulations may cause erosion to the dental tissues.

Aims:

The aim of this study is to evaluate the erosive potential of pediatric liquid medicinal syrups on the deciduous teeth.

Subjects and Methods:

A total of sixty extracted/exfoliated noncarious deciduous molars were used. Four medical syrups were used (viz., 1 – artificial saliva [control], 2 – Ferium XT, 3 – Crocin syrup, 4 – Ambrolite-D) and the teeth were equally divided into the four groups (n = 15) for the immersion cycle, following which the teeth were examined for surface microhardness at 7, 14, 21, and 28 days.

Statistical Analysis Used:

ANOVA and post hoc analysis were applied.

Results:

The time and immersion media interaction demonstrated that antitussives produced a significant and gradual loss of surface microhardness on all days (viz., 7, 14, 21, and 28 days), but a statistically significant difference was seen only between 7^th and 28^th day (P < 0.05).

Conclusions:

The knowledge of the erosive potential of commonly used syrups is mandatory as erosion in children teeth may be associated with dental hypersensitivity, loss of the occlusal vertical dimension, eating difficulties, poor esthetics, pulp exposure, and abscesses. Mouth rinsing with water after taking the medication; addition of calcium, fluoride, or phosphate to formulations; and consumption of the medication at meal times have been recommended to avoid tooth damage that is caused by the regular use of medication.

Assessment of nickel release from various dental appliances used routinely in pediatric dentistry

Context:

The use of nickel-containing alloys in dentistry has been questioned because of the biological liabilities of nickel and the release of nickel ions from dental appliances into the oral cavity. The potential health hazards of nickel and chromium and their compounds have been the focus of attention for more than 100 years. It has established that these metals could cause hypersensitivity.

Aims:

To assess the nickel release from various dental appliances used in pediatric dentistry.

Settings and Design:

It is a in vitro study.

Materials and Methods:

The study was undertaken to analyze in vitro biodegradation of space maintainers and stainless steel crowns made out of stainless steel materials from different manufacturers. The leaching effect simulating the use of clinical practice was studied by keeping the respective number of Stainless Steel Crowns and space maintainers in the artificial saliva incubating at 37°C and analyzing for nickel release after 1,7,14,21 and 28 days using atomic absorption spectrophotometer.

Statistical Analysis:

The results were statistically analyzed by using One way ANOVA and repeated measures of ANOVA was applied at different time intervals i.e. 1,7,14,21,28 days. The critical value for statistical significance was set at P = 0.05.

Results:

Results showed that there was measurable release of nickel which reached maximum level at the end of 7 days which was statistically significant (P < 0.05).

Conclusions:

The release of nickel and chromium very much below when compared with the average dietary intake of nickel (200-300 ppm/day) which were not capable of causing any toxic effects.

Frequency of Addictive Habits and its Association with Oral Diseases Among a Cross Section of Indian Police Personnel Connotation

OBJECTIVE

To assess the frequency of adverse addictive habits, specially alcohol and tobacco usage, among police personnel of Bhopal City, Central India and its association with the frequency of oral mucosal lesions and periodontal diseases.

STUDY DESIGN

Across-sectional analytical study.

PLACE AND DURATION OF STUDY

Bhopal City, Capital of Madhya Pradesh State, Central India, from February to April 2013.

METHODOLOGY

All the police personnel posted at various police stations were interviewed and clinically examined. Police personnel who did not cooperate or were not willing, were excluded from the study. Chi-square test was used to analyze categorical variables.

RESULTS

Atotal of 781 subjects were interviewed for the various forms of adverse habits, followed by clinical assessment of oral mucosal lesions and periodontal status using WHO 1997 criteria. The mean age of study subjects was 40.58 ±9.84 years. Usage of tobacco was found among 55% and only 1.3% of subjects consumed alcohol. The prevalence of oral mucosal lesions and periodontal diseases was significantly higher among tobacco users.

CONCLUSION

There was high usage of tobacco among police personnel in Bhopal City, India with a detrimental effect on oral health.

Knowledge of evidence-based dentistry among academic dental practitioners of Bhopal, India: a preliminary survey

This study aimed to characterize the knowledge of evidence-based dentistry (EBD) among dental faculty members in the city of Bhopal in central India. A cross-sectional questionnaire was administered at two dental colleges in Bhopal City. All dental faculty members who were present on the day of the study and who agreed to participate were included in the study. A total of 50 dental faculty members returned the questionnaire. Six Likert-type questions were asked, and the percentages of various responses were used for analysis. Sixteen faculty members (32.0%) strongly agreed that EBD is a process of making decisions based on scientifically proven evidence. Fifteen faculty members (30.0%) strongly disagreed or disagreed with the item stating that the best and quickest way to find evidence is by reading textbooks or asking experienced colleagues. Thirteen faculty members (26.0%) strongly agreed that EBD allows dentists to improve their scientific knowledge and clinical skills. It is recommended that EBD be included in undergraduate and postgraduate curricula and in intensive continuing dental education programs that are conducted for dental faculty members.

Routine upper GI series after gastric bypass does not reliably identify anastomotic leaks or predict stricture formation

BACKGROUND

Many surgeons who perform Roux-en-Y gastric bypass (RYGB) for morbid obesity routinely obtain an upper gastrointestinal (GI) series in the early postoperative period to search for anastomotic leaks and signs of stricture formation at the gastrojejunostomy. We hypothesized that this practice is unreliable.

METHODS

We analyzed 654 consecutive RYGBs, of which 63% were completed laparoscopically. An upper GI series was obtained in 634 (97%) patients. The radiographic findings (leak or delayed emptying) were compared with clinical outcomes (leak or stricture formation) to calculate the sensitivity and specificity. Univariate analysis identified risk factors for leaks or stricture formation; events were too few for multivariate analysis.

RESULTS

Of 634 routine upper GI series, anastomotic leaks at the gastrojejunostomy were diagnosed in 5 (0.8%); 2 of these 5 were later reinterpreted as artifacts. Four leaks were not seen on the initial upper GI series, yielding an overall sensitivity of 43% and a positive predictive value (PPV) of 60%. Univariate analysis showed that cases done early (odds ratio [OR] 5.4 for the first 100 cases, p = 0.02) and prolonged operating time (OR 7.8 for cases >or= 300 min, p = 0.01) were associated with leaks. Emptying into the Roux-en-Y limb was delayed in 127 (20%) of the upper GI series. Strictures requiring dilatation developed in 16 (2.4%) patients. The PPV of delayed emptying for stricture formation was 6%. Risk factors for stricture formation included stapled anastomosis (OR 7.8, p = 0.002), surgeon inexperience (OR 2.9 for first 50 cases, p = 0.04), and delayed emptying (OR 3.3; p = 0.02).

CONCLUSIONS

Because the incidence of anastomotic complications and the sensitivity of upper GI series were both low, routine upper GI series did not reliably identify leaks or predict stricture formation. A selective approach, whereby imaging is reserved for patients with clinical evidence of a leak or stricture, may be more appropriate.