Microstructural Characterization of GaN Grown on SiC.

GaN films have been grown on SiC substrates with an AlN nucleation layer by using a metal organic chemical vapor deposition technique. Micro-cracking of the GaN films has been observed in some of the grown samples. In order to investigate the micro-cracking and microstructure, the samples have been studied using various characterization techniques such as optical microscopy, atomic force microscopy, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy (TEM). The surface morphology of the AlN nucleation layer is related to the stress evolution in subsequent overgrown GaN epilayers. It is determined via TEM evidence that, if the AlN nucleation layer has a rough surface morphology, this leads to tensile stresses in the GaN films, which finally results in cracking. Raman spectroscopy results also suggest this, by showing the existence of considerable tensile residual stress in the AlN nucleation layer. Based on these various observations and results, conclusions or propositions relating to the microstructure are presented.

Can post-operative antibiotic prophylaxis following elective laparoscopic cholecystectomy be completely done away with in the Indian setting? A prospective randomised study.

PREMISE AND OBJECTIVE:: Elective laparoscopic cholecystectomy (LC) has low risk for post-operative infectious complications; still most clinicians use persistent post-operative prophylactic antibiotics out of habit, tradition, or simply as defensive practice due to evolving medicolegal implications of a large number of surgeries being showcased as daycare or next day discharge procedures. This randomised prospective trial was done to test the need for such prophylaxis in cases of elective LC in a rural/semi-urban setting. MATERIALS AND METHODS:: Two hundred and ten successive patients undergoing elective LC were randomised into groups receiving single dose of injection ceftriaxone at the time of induction of anaesthesia, (Group A = 112 cases) and those who in addition to above received injection ceftriaxone twice daily for 2 days postoperatively (Group B = 98 cases). Post-operative infectious complications between two groups were compared for variables such as age, sex, body mass index and bile/stone spillage. RESULTS:: There was no significant difference in surgical site infection rates between the groups for variables such as age, sex, body mass index, duration of symptoms, American Society of Anesthesiologists grade, duration of surgery and hospital stay. Intraoperative spillage of stones (9.8% [A]: 5.1% [B]) did not increase infectious complications even in the presence of positive bile culture (Group A, N = 7 vs. Group B, N = 3). An operative time of greater than 60 min was found to be associated with increased surgical site infection (P = 0. 0006). CONCLUSION:: Single dose of ceftriaxone at the time of induction is adequate prophylaxis following elective LC even in the rural/semi-urban Indian setting and routine continued administration of antibiotic should be abandoned as it contributes to adverse reactions, drug resistance and unnecessary financial burden.

Association between components of metabolic syndrome and prostatic enlargement: An Indian perspective.

BACKGROUND: To find association between prostate gland volume to components of the metabolic syndrome. METHODS: Cross-sectional, observational study in a tertiary care hospital of the Armed Forces of India. A total of 115 male patients aged 50-65 years attending the Urology OPD between Jan 2014 and July 2015 with lower urinary tract symptoms (LUTS) were included. Men with known malignant disease including carcinoma prostate, those on medical management for BPH and individuals with previous history of surgery related to urinary bladder/prostate were excluded. Blood Pressure (BP), weight in kgs, height, waist and hip circumference to nearest cm were recorded. Body Mass Index (BMI) and Waist/Hip ratio (WHR) were calculated. Fresh serum was analysed for lipid profile and glycaemic levels. The International Diabetes Federation (IDF) - 2005 guideline for metabolic syndrome was used for the diagnosis. The total prostate volume and the severity of LUTS as per AUA Symptom index were considered as the primary and secondary outcome measure respectively. Statistical software SPSS version 20 was used for analysis. Mean prostate volume was compared with the components of MetS. An alpha level of 5% was considered significant. RESULTS: The study showed positive association between prostate volume with metabolic syndrome and its four components - raised blood pressure, fasting blood glucose and triglycerides and HDL ≤ 40 mg/dl. No correlation was found with waist circumference. CONCLUSION: Our study indicates that metabolic syndrome and its individual components may predispose patients to a higher risk of prostatic enlargement/LUTS.

Tailoring Structural, Chemical, and Photocatalytic Properties of ZnO@ß-SiC Composites: The Effect of Annealing Temperature and Environment.

For achieving unified functionalities of rare-earth free materials, the development of innovative zinc oxide and ß-silicon carbide (ZnO@ß-SiC) composites by a solid-state reaction method is presented. The evolution of zinc silicate (Zn2SiO4) is evidenced by X-ray diffraction when annealed in air beyond 700 °C. Detailed X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses reveal the involvement of silicon dioxide in forming Zn2SiO4. Transmission electron microscopy and the associated energy-dispersive X-ray spectroscopy elucidate the evolution of the zinc silicate phase at the ZnO/ß-SiC interface, though it can be averted by vacuum annealing. These results manifest the importance of air in oxidizing SiC before a chemical reaction with ZnO from 700 °C. Finally, ZnO@ß-SiC composites are found to be promising for methylene blue dye degradation under ultraviolet radiation, but the annealing above 700 °C is detrimental due to the evolution of a potential barrier in the presence of Zn2SiO4 at the ZnO/ß-SiC interface.

Optoelectronics of Atomic Metal-Semiconductor Interfaces in Tin-Intercalated MoS2.

Metal-semiconductor interfaces are ubiquitous in modern electronics. These quantum-confined interfaces allow for the formation of atomically thin polarizable metals and feature rich optical and optoelectronic phenomena, including plasmon-induced hot-electron transfer from metal to semiconductors. Here, we report on the metal-semiconductor interface formed during the intercalation of zero-valent atomic layers of tin (Sn) between layers of MoS2, a van der Waals layered material. We demonstrate that Sn interaction leads to the emergence of gap states within the MoS2 band gap and to corresponding plasmonic features between 1 and 2 eV (0.6-1.2 µm). The observed stimulation of the photoconductivity, as well as the extension of the spectral response from the visible regime toward the mid-infrared suggests that hot-carrier generation and internal photoemission take place.

Enhancing Light-Matter Interactions in MoS2 by Copper Intercalation.

The intercalation of layered compounds opens up a vast space of new host-guest hybrids, providing new routes for tuning the properties of materials. Here, it is shown that uniform and continuous layers of copper can be intercalated within the van der Waals gap of bulk MoS2 resulting in a unique Cu-MoS2 hybrid. The new Cu-MoS2 hybrid, which remains semiconducting, possesses a unique plasmon resonance at an energy of ≈1eV, giving rise to enhanced optoelectronic activity. Compared with high-performance MoS2 photodetectors, copper-enhanced devices are superior in their spectral response, which extends into the infrared, and also in their total responsivity, which exceeds 104 A W-1 . The Cu-MoS2 hybrids hold promise for supplanting current night-vision technology with compact, advanced multicolor night vision.

Nomophobia: A Cross-sectional Study to Assess Mobile Phone Usage Among Dental Students.

INTRODUCTION: Mobile phones were originally seen as a gadget for communication but currently, the internet enabled mobile phones have become an integral part of our daily life. Their benefits are incomparable but at the same time, they have some negative effects too. AIM: To assess the pattern of usage of mobile phones and its effects on the academic performance of students. MATERIALS AND METHODS: A descriptive cross-sectional study was conducted amongst 554 students of D. J. College of Dental Sciences and Research through a self-administered questionnaire to collect the data regarding the usage and associated anxiety with mobile phone. RESULTS: About 39.5% students agreed that they score low marks in professional exams if they spend more time on phone. The number of students who frequently checked their cell phone during their classes or while doing clinical work were 24.7% . A total of 24.12% of the students were found to be nomophobic and at risk of being nomophobes were 40.97%. A statistically significant difference was found among preclinical, clinical, interns and postgraduates regarding the usage and effect of mobile phone on them. CONCLUSION: The pattern of usage of mobile phone among dental students showed alarming indication that students have been addicted to mobile phone which in turn affect their academic performance in a negative way. It would be useful to advise the students about the controlled as well as proper usage of mobile phone.

Effect of Chlorhexidine with Fluoride Mouthrinse on Plaque Accumulation, Plaque pH - A Double Blind Parallel Randomized Clinical Trial.

INTRODUCTION: Mouthwashes are important means used in chemical control of dental plaque. There is strong evidence suggestive of better effectiveness, when fluoride is added to chlorhexidine mouthwash. AIM: To assess the anti-plaque efficacy of Chlorhexidine combined with Fluoride mouthwash and to measure its impact on plaque accumulation and on plaque pH. MATERIALS AND METHODS: Initially 100 subjects were screened. A double blind, parallel randomized clinical trial was conducted on 30 subjects after applying inclusion and exclusion criteria. Other independent variables were matched before randomly allocating them in three groups: Group A-Chlorhexidine as positive control, Group B-Chlorhexidine + Fluoride as test group and Group C- Distilled water as negative control. Oral prophylaxis of participants was done before onset of the study. Plaque pH was assessed before and immediately after rinsing at 0, 5 and 10 minutes interval and after 7 days with digital pH electrode (pHepR pH meter, Hanna Instruments R10285) and accumulation of plaque was recorded by Turesky et al., modification of Quigley Hein Plaque Index (1970). ANOVA test was used for statistical analysis. RESULTS: Although there was a statistically significant reduction in mean plaque scores from baseline to seven days in both Groups A and B, Group B showed better anti-plaque efficacy . Almost equal drop in plaque pH was seen for both the groups at 5 and 10 minutes. CONCLUSION: Better anti-plaque efficacy was observed in Group B (Chlorhexidine and Fluoride combination) with minimum variation of plaque pH.

Effect of Probiotic Curd on Salivary pH and Streptococcus mutans: A Double Blind Parallel Randomized Controlled Trial.

BACKGROUND: Dairy products like curd seem to be the most natural way to ingest probiotics which can reduce Streptococcus mutans level and also increase salivary pH thereby reducing the dental caries risk. OBJECTIVES: To estimate the role of probiotic curd on salivary pH and Streptococcus mutans count, over a period of 7 days. MATERIALS AND METHODS: This double blind parallel randomized clinical trial was conducted at the institution with 60 caries free volunteers belonging to the age group of 20-25 years who were randomly allocated into two groups. Test Group consisted of 30 subjects who consumed 100ml of probiotic curd daily for seven days while an equal numbered Control Group were given 100ml of regular curd for seven days. Saliva samples were assessed at baseline, after ½ hour 1 hour and 7 days of intervention period using pH meter and Mitis Salivarius Bacitracin agar to estimate salivary pH and S. mutans count. Data was statistically analysed using Paired and Unpaired t-test. RESULTS: The study revealed a reduction in salivary pH after ½ hour and 1 hour in both the groups. However after 7 days, normal curd showed a statistically significant (p< 0.05) reduction in salivary pH while probiotic curd showed a statistically significant (p< 0.05) increase in salivary pH. Similarly with regard to S. mutans colony counts probiotic curd showed statistically significant reduction (p< 0.05) as compared to normal curd. CONCLUSION: Short-term consumption of probiotic curds showed marked salivary pH elevation and reduction of salivary S. mutans counts and thus can be exploited for the prevention of enamel demineralization as a long-term remedy keeping in mind its cost effectiveness.

Association of Dermatoglyphic Peculiarities with Dental Caries in Preschool Children of Lucknow, India.

BACKGROUND: Dermatoglyphics refers to study of the intricate dermal ridge configurations on the skin covering the palmar and plantar surfaces of hand and feet. The basis of considering dermatoglyphic patterns as genetic marker for dental caries is that the epithelium of finger buds as well as enamel has ectodermal origin, and both develop at the same time of intrauterine life. AIM: To assess the relationship between fingerprint patterns and dental caries among preschool children of Lucknow city. STUDY DESIGN: This study was of cross-sectional design. MATERIALS AND METHODS: The study group comprised 512 preschool children 2-6 years of age. The prevalence of caries was recorded using "Dentition status and treatment needs" (WHO basic oral health assessment form, 1997). They were divided into three groups as follows: Group I (dmft score = 0-2), group II (dmft score = 3-4) and group III (dmft score ≥5). The handprints of each child were taken using a stamp pad. The fingertip patterns were analyzed according to the classical method and were classified according to the topological method. The frequency of occurrence of type of dermatoglyphic pattern on fingertip of each digit was noted. STATISTICS: Chi-square test was used to test the significant difference in proportions. Means were compared using Student's t-test and analysis of variance (ANOVA) or F-test. RESULTS: Subjects belonging to groups II and III showed maximum occurrence of whorl pattern on all digits. Group I subjects had maximum occurrence of arch pattern. All the variables had statistically significant value, with a degree of divergence of specific dermatoglyphic patterns among all three groups. CONCLUSION: The dental caries susceptibility of an individual increased with incidence of whorl pattern and it decreased with incidence of arch pattern. How to cite this article: Singh E, Saha S, Jagannath GV, Singh S, Saha S, Garg N. Association of Dermatoglyphic Peculiarities with Dental Caries in Preschool Children of Lucknow, India. Int J Clin Pediatr Dent 2016;9(1):39-44.

Effectiveness of oral health education versus nicotine replacement therapy for tobacco cessation- a parallel randomized clinical trial.

BACKGROUND: India has millions of tobacco users. It is the leading cause of deaths due to oral cancer and hence needs effective strategies to curb it. Hence the aim of present study was to evaluate and compare the effectiveness of Oral Health Education (OHE) and Nicotine Replacement Therapy (NRT) in tobacco cessation. MATERIAL AND METHODS: The clinical trial consisted of Manohar Lal Kapoor (MLK) factory workers (n= 40) giving history of tobacco consumption (smoking/smokeless) within past 30 days. They were randomized into OHE (n=20) and NRT (n=20) groups. Baseline evaluation (demographic, smoking/ smokeless behaviour) was done. Fagerstrom test was used for Nicotine Dependence (FTND) and to assess nicotine addiction level. Follow up was done at an interval of 1week, 2 weeks, 1 month, 2 months and 3 months to assess the reduction in the mean FTND score. "Nano-CheckTM Rapid Nicotine test" was used for the qualitative detection of cotinine in human urine. Appropriate statistical analysis was performed (Paired and Unpaired t test). RESULTS: In both OHE and NRT group there was a significant reduction (p< 0.00001) in mean Fagerstrom score at every follow up but when both the groups were compared mean Fagerstrom score reduction was more in NRT than OHE at all time interval though it was not statistically significant (p>0.05). CONCLUSIONS: NRT is better than OHE when both the groups were compared. However, it was found that any intervention given to tobacco users either NRT or OHE is helpful for the patients in the process of quitting tobacco. KEY WORDS: Tobacco cessation, nicotine replacement therapy, oral health education, fagerstrom test, urine cotinine.

Prevalence and Association of Developmental Defects of Enamel with, Dental- Caries and Nutritional Status in Pre-School Children, Lucknow.

BACKGROUND: Developmental Defects of Enamel in the primary dentition may be associated and predictors of dental caries and nutritional status. The aim of the present study was to assess the Prevalence of Developmental Defects of Enamel and its Association with, Dental-Caries and Nutritional Status in Pre-School Children of Lucknow, India. MATERIALS AND METHODS: Multistage Sampling was done. A total of 302 pre-school (Rural and Urban) children were examined. Type III examination was conducted with WHO Probe. Developmental Enamel Defects (DED) and Dental Caries were assessed using WHO (1997) Proforma. RESULTS: The prevalence of DED of any type was 39.9% with that of demarcated opacities being the highest, followed by hypoplasia. The most frequently affected teeth were maxillary anterior teeth, while the least affected teeth were mandibular incisors. The mean dmft was 3.5. A positive association between DED and caries was observed. Association between Dental Caries & BMI was non-significant whereas Pearson correlation showed a negative correlation between the two. CONCLUSION: The prevalence of enamel defects and caries was high, as the enamel defects were strongly associated with caries.

Effectiveness of outreach program: a three year follow-up study among 12 years school students in lucknow.

AIM: To assess the effectiveness of outreach program in the 12 years school going children during a three year follow up period of Lucknow city. MATERIALS AND METHODS: A random sample of 298 school going children of age 12 years was drawn from adopted schools of Lucknow. Three years later the same population was re-examined with a population of 242 children of 15 y age group. The oral health status of these children was accessed by using WHO 1997 profoma. RESULTS: Significantly (p<0.001) higher proportion of children had healthy gingival, healthy periodontal status after three years. The difference in regard to crowding in the incisal segment in 2010 and 2013 was statistically highly significant (p<0.001). CONCLUSION: The findings of the study showed that after providing regular dental check up and treatment camps in the three adopted schools after three year follow up study from 2010-2013 showed positive impact on the children oral hygiene status and has been estimated to be on the more positive aspect in future also.

Prevalence of Malocclusion and its Psycho-Social Impact among 12 To 15-Year-old School Children in Lucknow City.

BACKGROUND: Facial aesthetics affects how people are perceived by society and how they perceive themselves. Anterior malocclusion can have an impact on the overall facial appearance. AIM: The aim of the study was to assess the prevalence of malocclusion and its psycho-social impact among 12 to 15 yrs old school children in Lucknow city. MATERIALS AND METHODS: The study consisted of collection of information for psychosocial assessment using a questionnaire and clinical examination of malocclusion. Data regarding psychosocial impact of dental aesthetics was collected using a Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) given by Klages et al., (2006). RESULTS: 15.57% children belonged to the definite malocclusion category and 5.41% to the handicapped malocclusion category. The mean Dental self confidence score differed significantly among both male (p≤0.001) and female children (p≤0.001) across the age groups. The mean Social impact score did not differ significantly among both male (p≤0.31) and female children (p≤0.12) across the age groups. CONCLUSION: The results of the present study imply that dental aesthetics had a significant impact on the psychosocial aspects of human life irrespective of the gender.

Cognitive Behavioural Therapy versus Basic Health Education for Tobacco Cessation among Tobacco Users: A Randomized Clinical Trail.

INTRODUCTION: Tobacco is the greatest disease-producing product which is known to man and it is a primary cause of many oral diseases and adverse oral conditions. This study was conducted to bring the behavioural changes and to educate individuals about the harmful effects of tobacco. METHOD: Subjects reporting to the tobacco cessation centre of the Department of Public Health Dentistry and giving a history of tobacco consumption (smoking/smokeless) within past 30 day period were randomized into 2 groups: cognitive behavioural therapy (CBT) group (study group) and Basic health education (BHE) group (control group). Baseline evaluation (of demographic parameters, smoking/ smokeless behaviour) was done and Fagerstrom's test for Nicotine Dependence (FTND) was used to assess subjects' nicotine addiction levels. Follow up was done at intervals of 2 weeks and 4 weeks to assess the reduction in the mean FTND score. Appropriate statistical analysis was performed (Paired and Unpaired t-test). RESULTS: Of all the subjects who reported to the department, 40 subjects were recruited in the study. A majority of the subjects were males who belonged to rural areas, who had completed high school and most of them had consumed more than 10 sachets of pan masala daily, for an average of 10 years. In both CBT and BHE groups, significant reductions in mean Fagerstrom scores at 1st and 2nd follow ups from baseline and between 1st and 2nd follow ups were seen. But when both groups were compared, reductions in mean Fagerstrom scores were found to be more in CBT group than in BHE group at all time intervals, though it was not statistically significant. CONCLUSION: Any intervention given to tobacco users from either CBT or BHE groups, helped the patients in quitting habit of tobacco.

The maternal socioeconomic status and the caries experience among 2-6 years old preschool children of lucknow city, India.

AIM: The aim of the present study was to assess the maternal socioeconomic status and the caries experience among 2-6 years old preschool children of Lucknow city, India. MATERIAL AND METHODS: A sample of 512 preschool going children were selected through a multistage cluster random sampling. Their mothers provided information regarding their demographic data. Their socioeconomic statuses were elicited by using the modified B.G.L. Prasad's classification for the year 2010. Their mothers' education, occupations and incomes were also recorded. The dental caries experience was recorded by using the dentition status and the treatment needs (WHO Basic Oral Health Survey 1997). The association between the socioeconomic status and the caries experience was obtained by using the Chi - square test. One way ANOVA was used for the multiple group comparisons. RESULTS: The prevalence of nursing caries was 33.01%. The association between the presence of nursing caries and a lower status of the mother's education and occupation and socioeconomic position proved to be statistically significant (p<0.001). CONCLUSION: Instilling positive attitudes in the parents, especially in the mothers, towards the prevention of nursing caries, would reduce its prevalence at this tender age of life.

Efficiency of traditional chewing stick (miswak) as an oral hygiene aid among Muslim school children in Lucknow: A cross-sectional study.

BACKGROUND: Oral hygiene practices vary from country to country and from culture to culture. 'Miswak' as an oral hygiene aid is a pre-Islamic custom contributed to ritual purity. The beneficial effects of miswak in respect to oral hygiene and dental health are attributed to its mechanical and pharmacological actions. AIM: The aim of the present study was to assess and compare the oral hygiene status and gingival conditions in Muslim school children of Lucknow city. MATERIALS & METHOD: Study population comprised of 297 individuals in age group of 12-15 years from residential and non-residential Islamic institutions in Lucknow city. Oral hygiene status was assessed using the Gingival Index (1963), Oral Hygiene Index-Simplified (1964) and Plaque Index (1964). RESULTS: Statistically significant difference of mean gingival index score was observed among miswak and toothbrush & toothpaste users. Miswak users had lower mean gingival index score. Mean plaque score was lowest among combined users of toothbrush and miswak. CONCLUSION: Miswak users exhibited a better mean gingival score as compared to toothbrush & toothpaste users, while the mean plaque score was lowest among the combined users of toothbrush and miswak.