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The light absorption properties of brown carbon aerosols generated in a lab scale experiment from wood (Magnifera indica) and dung cake were studied. Mie theory along with experimentally derived values for imaginary refractive index was used to estimate mass absorption coefficient for the samples. It was observed that for both wood and dung cake major portion of brown carbon were generated above 150°C. The light absorbing properties of brown carbon from wood depended on temperature of pyrolysis which was not the case for dung cake. The spectral dependence of absorption for brown carbon samples was estimated in terms of Absorption Angstrom Exponent and found to be greater than 2. The brown carbon aerosols from dung cake pyrolysis were having twice the light absorbing potential (in the wavelength range 280 nm to 750 nm) than brown carbon emitted from mango tree wood pyrolytic combustion.

Objective: To assess knowledge, regarding use of rubber dam during root canal treatment among dentists in Rawalpindi and Islamabad.Study Design: Descriptive cross-sectionPlace and Duration of Study:  Operative Department Armed Forces Institute of Dentistry (AFID) Rawalpindi from 1st March 2020 to 31st May 2020. Materials and Methods:  A web-based questionnaire, comprising of close-ended questions in the categories of demographics, clinical experience, usage of isolation techniques and knowledge regarding rubber dam (RD) use, procedures, and contraindications was sent through internet to 387 dentists of Rawalpindi and Islamabad. The response rate was 77.5%. Data was analyzed using SPSS version 20, and was displayed as numbers and percentages.Results: 79 out of 300 i.e. 26.33% respondents used rubber dam in restorative and endodontic procedures. 73.3% were using other methods of isolation such as cotton rolls, saliva ejectors and high volume suction. All the respondents were aware about the importance of rubber dam. The most challenging factor for dentists (57.3%) was high influx of patients per day.Conclusion: Rubber dam is not being used commonly by participating dentists of tertiary dental hospitals of Rawalpindi and Islamabad mainly because of high patient turnover per day, combination of cotton rolls and saliva high-volume ejector or gauze is the most common alternative to rubber dam isolation. Rubber dam isolation is highly recommended.

Objective: To assess the knowledge and attitude of dentists of Rawalpindi and Islamabad towards the use andsafety of amalgam, observance of mercury hygiene and amalgam waste management.Study Design: Cross Sectional survey.Place and Duration of Study: The study was carried out at Operative Dentistry Department of AFIDst th Rawalpindi, from 1 March to 31 April 2021.Materials and Methods: An online questionnaire was circulated among 384 private and public hospital dentistsof Rawalpindi and Islamabad. Final questionnaire consisted of close ended questions related to demographicdetails, questions regarding the handling and disposal of amalgam and perception of dentists regardingmercury hygiene. Data was analyzed using SPSS version 21 and evaluated as frequencies, percentages, meanand standard deviation. Chi-square test was used to correlate demographic to the responses of the participantsto the items of the questionnaire.Results: Majority of the dentists were doing 5-10 amalgam restorations per week (34.6%) but they didn't placerubber dam while restoring tooth with amalgam (95.7%). Most of the dentists take no specific measures forstoring leftover amalgam (65.4%) and do not periodically monitor mercury vapor (91.5%).Conclusion: The majority of dentists of Rawalpindi and Islamabad are not following dental mercury hygienerecommendations as there is a significant lack of knowledge regarding mercury hygiene and amalgam wastedisposal.

The objective of this multi-centre study was to analyse the knowledge of parents as compared to medical-doctors regarding avulsion-injuries. A validated and piloted questionnaire was circulated among two equal groups (130 participants each) of medical-doctors and the general public. Data was analysed using SPSS version 19. A total of 131 (89%) participants had a university degree and 185 (71%) had a full time employment. One hundred and eighty-seven (72%) participants reported having no previous information regarding avulsion injuries, 195 (75%) considered their level of knowledge inadequate, and 63 (24%) had a previous history of dental trauma. A statistically significant number had information regarding avulsed permanent-teeth replantation (p = 0.02) but not deciduous-teeth (p = 0.26), whereas only 39 (15%) were aware of the right medium for tooth storage. Having seen or sustained an avulsion-injury and a higher qualification were statistically related to correct responses for some questions. A total of 106 (41%) of the participants wanted to be educated through written-material. In conclusion, the first-aid knowledge regarding tooth avulsion injuries in our population, irrespective of their level of academic education, is poor and needs supervised training. Keywords: Dental trauma, dental knowledge, dental management, tooth avulsion.