Three algebraically stabilized finite element schemes for discretizing convection-diffusion-react... more Three algebraically stabilized finite element schemes for discretizing convection-diffusion-reaction equations are studied on adaptively refined grids. These schemes are the algebraic flux correction (AFC) scheme with Kuzmin limiter, the AFC scheme with BJK limiter, and the recently proposed Monotone Upwind-type Algebraically Stabilized (MUAS) method. Both, conforming closure of the refined grids and grids with hanging vertices are considered. A non-standard algorithmic step becomes necessary before these schemes can be applied on grids with hanging vertices. The assessment of the schemes is performed with respect to the satisfaction of the global discrete maximum principle (DMP), the accuracy, e.g., smearing of layers, and the efficiency in solving the corresponding nonlinear problems.
Background: Implantology is an emerging field of science, although there are not many subjects wh... more Background: Implantology is an emerging field of science, although there are not many subjects who opt for this treatment modality. Replacement of missing or lost teeth with dental prostheses supported by oral implants has been accepted and received positive evaluations from patients who have undergone implant treatment. Today, implant-supported restorations can be considered the treatment of choice from the perspective of occlusal support, preservation of adjacent teeth, and avoidance of a removable partial denture. Currently, dental implants are widely accepted as a prosthetic treatment of completely or partially edentulous patients. This led to widespread acceptance and popularity of dental implants within the dental professional community. Aim: The aim of this study was to evaluate knowledge, attitude, and awareness of dental implants in residents of Uttarakhand. Materials and Methods: A total population of 500 subjects were randomly selected and evaluated based on filled questionnaire responses. Results: A low level of knowledge was observed on analyzing the filled responses among the studied population. Conclusion: General public should be made aware on dental implants as treatment modality along with the focus on increasing the cost feasibility.
AIM The present study was done to evaluate the in vivo cariostatic efficacy of aqueous and ethano... more AIM The present study was done to evaluate the in vivo cariostatic efficacy of aqueous and ethanolic extracts of liquorice to ascertain whether it could be developed into a caries-preventive regimen basically targeted for use in the pediatric population. MATERIALS AND METHODS Thirty schoolchildren of 6-12-year-old were selected for the study. Powder of Glycyrrhiza glabra is used to prepare the gel with various concentration of aqueous and ethanolic liquorice gel. The preweighed dose was delivered through the vials. The drug concentrations were based on their respective minimum bactericidal concentration (MBC) values against Streptococcus mutans, which were calculated earlier. And it is divided into three groups, i.e., group I: aqueous liquorice extract 1.75 g/10 mL saline, group II: ethanolic liquorice extract 350 mg/10 mL, and group III: hexidine (0.2% chlorhexidine, CHX). For statistical analysis, Tukey's post hoc with one-way analysis of variance (ANOVA) and t test were appli...
Computers & Mathematics with Applications, 2021
In this work, we propose a residual-based a posteriori error estimator for algebraic flux-correct... more In this work, we propose a residual-based a posteriori error estimator for algebraic flux-corrected (AFC) schemes for stationary convection-diffusion equations. A global upper bound is derived for the error in the energy norm for a general choice of the limiter, which defines the nonlinear stabilization term. In the diffusion-dominated regime, the estimator has the same convergence properties as the true error. A second approach is discussed, where the upper bound is derived in a posteriori way using the Streamline Upwind Petrov Galerkin (SUPG) estimator proposed in [JN13]. Numerical examples study the effectivity index and the adaptive grid refinement for two limiters in two dimensions.
A presente dissertação é resultado de muito trabalho, dedicação e superação das minhas limitações... more A presente dissertação é resultado de muito trabalho, dedicação e superação das minhas limitações. Em minha jornada contei com o precioso apoio de várias pessoas na Ufes e no Senai. Em primeiro lugar, agradeço imensamente ao meu orientador, Professor Doutor Marcelo Lima, que com empenho e paciência me conduziu por caminhos que jamais havia trilhado, me corrigindo e orientando semanalmente, não permitindo que eu me perdesse diante de tantos temas que me fascinaram neste percurso. Aos professores Antonio Henrique Pinto, Regina Simões e Antonia Colbari por fazerem parte da minha banca e pelas importantes contribuições. Aos professores Vania Araújo, Rogério Drago e Carlos Ferraço com quem pude desfrutar de momentos de aprendizagens tão importantes no início desse mestrado. Aos meus colegas da turma 30M e do grupo de pesquisa pelo apoio, amizade e respeito que sempre me dedicaram, especialmente à
Background: Saliva plays a major role in preserving the integrity of oral tissues. Chronic renal ... more Background: Saliva plays a major role in preserving the integrity of oral tissues. Chronic renal failure patient undergoes many oral and salivary changes for which they require special oral health care. The patient undergoing hemodialysis session has altered salivary composition. Many changes occur during hemodialysis that severely affect the flow rate and the biochemical composition of saliva. Methods: A total of 50 patients of end-stage renal disease undergoing hemodialysis for renal insufficiency were selected based on inclusion and exclusion criteria set prior to the study. These patients were compared with the control group who had already undergone hemodialysis. A total of 30 patients were selected as a control group. In this study, unstimulated whole saliva was collected by the spitting method before and after the dialysis session. Salivary flow rate, pH, and buffering capacities were measured. Results: Hemodialysis had a significant effect on the salivary flow rate. The mean pH of unstimulated whole saliva showed no significant changes before and after dialysis. The concentrations of urea, creatinine, chloride, and potassium in the whole saliva changed markedly before and after a hemodialysis session, whereas no significant difference was seen in the concentration of sodium and calcium. Conclusion: Through this study, we came into a conclusion that hemodialysis had a significant effect on salivary secretion and the biochemical composition of saliva. We conclude that the observed changes in salivary concentrations and the flow rate are mainly due to an increased watery secretion from the salivary glands and also saliva can be used as a tool for monitoring hemodialysis.
Minor salivary gland carcinomas are rarely reported. Mucoepidermoid carcinoma (MEC) is one of the... more Minor salivary gland carcinomas are rarely reported. Mucoepidermoid carcinoma (MEC) is one of the most common salivary gland malignancies. MEC accounts for 1% to 2% of major salivary gland neoplasms and 9% of minor gland tumors. It is most commonly seen in the parotid gland and usually appears as asymptomatic swelling. However, the palate is a frequent site when it occurs in the minor salivary glands. Follow-up of the patient is very important as local recurrence rate with conservative treatment is high. Here we are reporting a low-grade mucoepidermoid carcinoma involving palatal region in a 25-years-old female patient. The patient presented with a fast-growing swelling, invading the underlying anatomical structures and was treated successfully through the antrostomy procedure.
Journal of Indian Academy of Oral Medicine and Radiology, 2017
Introduction: The mental foramen is located in the apical region of the mandibular premolars. Var... more Introduction: The mental foramen is located in the apical region of the mandibular premolars. Variations in its position can be a cause of complications during local anesthesia or surgical procedures as well as in the diagnosis of lesions periapically. Aims and Objectives: The aim of this study was to determine the position and symmetry of mental foramen on a digital orthopantomogram (OPG), and the objective was to determine the frequency of location of mental foramen in relation to apices of teeth and interdental spaces on the panoramic radiographs. Materials and Methods: The study was done in the Department of Oral Medicine and Radiology, and 750 participants were selected in this study whose radiographic evaluation of mental foramen was done using OPG. The position of the image of the mental foramen was recorded according to criteria given by Wei Cheong Ngeow and Yusof Yuzawati. Statistical Analysis: The collected data were subsequently processed and analyzed using SPSS statistical package version 17. Results: We found that mental foramen is located below the second premolar in 74.4% of the patients followed by between two premolars in 19.3% of the population. In both males and females, most common position was in line with the second premolar followed by between two premolars. The mental foramen was symmetrical in 613 patients (81.7%) and asymmetrical in 137 patients (18.3%). Conclusion: In the present study, it was found that the most common position of the mental foramen was below second premolar followed by between two premolars. It was symmetrical in 81.7% of the population. In males and females, the most common position was below second premolar followed by between two premolars.
Point-Spread Function (PSF) modelling offers the capability to account for resolution degrading p... more Point-Spread Function (PSF) modelling offers the capability to account for resolution degrading phenomena within the PET reconstruction framework. PSF modelling improves resolution and enhances contrast, but at the same time significantly alters image noise properties and induces edge overshoot effect. Thus, studying the effect of PSF modelling on quantitation task performance can be very important. Frameworks explored in the past involve a dichotomy of PSF vs. no-PSF modelling. By contrast, the present work focuses on quantitative performance evaluation of standard uptake value (SUV) PET images, while incorporating a wide spectrum of PSF models, including those that under- and over-estimate the true PSF, for the potential of enhanced quantitation of standardized uptake values (SUVs). The developed framework first analytically models the true PSF, considering a range of resolution degradation phenomena (including photon non-collinearity, inter-crystal penetration and scattering) as present in data acquisitions with modern commercial PET systems. In the context of oncologic liver FDG PET imaging, we generated 200 noisy datasets per image-set (with clinically realistic noise levels) using an XCAT anthropomorphic phantom with liver tumours of varying sizes. These were subsequently reconstructed using the OS-EM algorithm with varying PSF-modelled kernels. We focused on quantitation of both SUVmean and SUVmax, including assessment of contrast recovery coefficients (CRC), as well as noise-bias characteristics (including both image roughness and coefficient-of-variability (CoV)), for different tumours/iterations/PSF kernels. It was observed that overestimated PSF yielded more accurate contrast recovery for a range of tumours, and typically improved quantitative performance. For a clinically reasonable number of iterations, edge enhancement due to PSF modelling (especially due to over-estimated PSF) was in fact seen to lower SUVmean bias in small tumours. Overall, the results indicate that exactly matched PSF modelling does not offer optimized PET quantitation, and that PSF overestimation may provide enhanced SUV quantitation. Furthermore, generalized PSF modelling may provide a valuable approach for in quantitative tasks such as diagnosis, prognostication and treatment-response assessment.
5-Ethyl-1,3,4-thiadiazole-2-amine have been synthesized by single step reaction. A series of hete... more 5-Ethyl-1,3,4-thiadiazole-2-amine have been synthesized by single step reaction. A series of heterocyclic azodyes were synthesized by coupling 8-hydroxyquinoline, 2,6-diaminopyridine, N,N-dimethyl aniline, 2-napthol and resorcinol with diazotized 5-ethyl-1,3,4-thiadiazol-2-amine in nitrosyl sulphuric acid. These dyes were characterized by UV, IR, 1 H NMR, 13 C NMR, elemental analysis and mass spectrometry for selected dyes. The synthesized compounds were also screened for biological activity.
Three algebraically stabilized finite element schemes for discretizing convection-diffusion-react... more Three algebraically stabilized finite element schemes for discretizing convection-diffusion-reaction equations are studied on adaptively refined grids. These schemes are the algebraic flux correction (AFC) scheme with Kuzmin limiter, the AFC scheme with BJK limiter, and the recently proposed Monotone Upwind-type Algebraically Stabilized (MUAS) method. Both, conforming closure of the refined grids and grids with hanging vertices are considered. A non-standard algorithmic step becomes necessary before these schemes can be applied on grids with hanging vertices. The assessment of the schemes is performed with respect to the satisfaction of the global discrete maximum principle (DMP), the accuracy, e.g., smearing of layers, and the efficiency in solving the corresponding nonlinear problems.
Background: Implantology is an emerging field of science, although there are not many subjects wh... more Background: Implantology is an emerging field of science, although there are not many subjects who opt for this treatment modality. Replacement of missing or lost teeth with dental prostheses supported by oral implants has been accepted and received positive evaluations from patients who have undergone implant treatment. Today, implant-supported restorations can be considered the treatment of choice from the perspective of occlusal support, preservation of adjacent teeth, and avoidance of a removable partial denture. Currently, dental implants are widely accepted as a prosthetic treatment of completely or partially edentulous patients. This led to widespread acceptance and popularity of dental implants within the dental professional community. Aim: The aim of this study was to evaluate knowledge, attitude, and awareness of dental implants in residents of Uttarakhand. Materials and Methods: A total population of 500 subjects were randomly selected and evaluated based on filled questionnaire responses. Results: A low level of knowledge was observed on analyzing the filled responses among the studied population. Conclusion: General public should be made aware on dental implants as treatment modality along with the focus on increasing the cost feasibility.
AIM The present study was done to evaluate the in vivo cariostatic efficacy of aqueous and ethano... more AIM The present study was done to evaluate the in vivo cariostatic efficacy of aqueous and ethanolic extracts of liquorice to ascertain whether it could be developed into a caries-preventive regimen basically targeted for use in the pediatric population. MATERIALS AND METHODS Thirty schoolchildren of 6-12-year-old were selected for the study. Powder of Glycyrrhiza glabra is used to prepare the gel with various concentration of aqueous and ethanolic liquorice gel. The preweighed dose was delivered through the vials. The drug concentrations were based on their respective minimum bactericidal concentration (MBC) values against Streptococcus mutans, which were calculated earlier. And it is divided into three groups, i.e., group I: aqueous liquorice extract 1.75 g/10 mL saline, group II: ethanolic liquorice extract 350 mg/10 mL, and group III: hexidine (0.2% chlorhexidine, CHX). For statistical analysis, Tukey's post hoc with one-way analysis of variance (ANOVA) and t test were appli...
Computers & Mathematics with Applications, 2021
In this work, we propose a residual-based a posteriori error estimator for algebraic flux-correct... more In this work, we propose a residual-based a posteriori error estimator for algebraic flux-corrected (AFC) schemes for stationary convection-diffusion equations. A global upper bound is derived for the error in the energy norm for a general choice of the limiter, which defines the nonlinear stabilization term. In the diffusion-dominated regime, the estimator has the same convergence properties as the true error. A second approach is discussed, where the upper bound is derived in a posteriori way using the Streamline Upwind Petrov Galerkin (SUPG) estimator proposed in [JN13]. Numerical examples study the effectivity index and the adaptive grid refinement for two limiters in two dimensions.
A presente dissertação é resultado de muito trabalho, dedicação e superação das minhas limitações... more A presente dissertação é resultado de muito trabalho, dedicação e superação das minhas limitações. Em minha jornada contei com o precioso apoio de várias pessoas na Ufes e no Senai. Em primeiro lugar, agradeço imensamente ao meu orientador, Professor Doutor Marcelo Lima, que com empenho e paciência me conduziu por caminhos que jamais havia trilhado, me corrigindo e orientando semanalmente, não permitindo que eu me perdesse diante de tantos temas que me fascinaram neste percurso. Aos professores Antonio Henrique Pinto, Regina Simões e Antonia Colbari por fazerem parte da minha banca e pelas importantes contribuições. Aos professores Vania Araújo, Rogério Drago e Carlos Ferraço com quem pude desfrutar de momentos de aprendizagens tão importantes no início desse mestrado. Aos meus colegas da turma 30M e do grupo de pesquisa pelo apoio, amizade e respeito que sempre me dedicaram, especialmente à
Background: Saliva plays a major role in preserving the integrity of oral tissues. Chronic renal ... more Background: Saliva plays a major role in preserving the integrity of oral tissues. Chronic renal failure patient undergoes many oral and salivary changes for which they require special oral health care. The patient undergoing hemodialysis session has altered salivary composition. Many changes occur during hemodialysis that severely affect the flow rate and the biochemical composition of saliva. Methods: A total of 50 patients of end-stage renal disease undergoing hemodialysis for renal insufficiency were selected based on inclusion and exclusion criteria set prior to the study. These patients were compared with the control group who had already undergone hemodialysis. A total of 30 patients were selected as a control group. In this study, unstimulated whole saliva was collected by the spitting method before and after the dialysis session. Salivary flow rate, pH, and buffering capacities were measured. Results: Hemodialysis had a significant effect on the salivary flow rate. The mean pH of unstimulated whole saliva showed no significant changes before and after dialysis. The concentrations of urea, creatinine, chloride, and potassium in the whole saliva changed markedly before and after a hemodialysis session, whereas no significant difference was seen in the concentration of sodium and calcium. Conclusion: Through this study, we came into a conclusion that hemodialysis had a significant effect on salivary secretion and the biochemical composition of saliva. We conclude that the observed changes in salivary concentrations and the flow rate are mainly due to an increased watery secretion from the salivary glands and also saliva can be used as a tool for monitoring hemodialysis.
Minor salivary gland carcinomas are rarely reported. Mucoepidermoid carcinoma (MEC) is one of the... more Minor salivary gland carcinomas are rarely reported. Mucoepidermoid carcinoma (MEC) is one of the most common salivary gland malignancies. MEC accounts for 1% to 2% of major salivary gland neoplasms and 9% of minor gland tumors. It is most commonly seen in the parotid gland and usually appears as asymptomatic swelling. However, the palate is a frequent site when it occurs in the minor salivary glands. Follow-up of the patient is very important as local recurrence rate with conservative treatment is high. Here we are reporting a low-grade mucoepidermoid carcinoma involving palatal region in a 25-years-old female patient. The patient presented with a fast-growing swelling, invading the underlying anatomical structures and was treated successfully through the antrostomy procedure.
Journal of Indian Academy of Oral Medicine and Radiology, 2017
Introduction: The mental foramen is located in the apical region of the mandibular premolars. Var... more Introduction: The mental foramen is located in the apical region of the mandibular premolars. Variations in its position can be a cause of complications during local anesthesia or surgical procedures as well as in the diagnosis of lesions periapically. Aims and Objectives: The aim of this study was to determine the position and symmetry of mental foramen on a digital orthopantomogram (OPG), and the objective was to determine the frequency of location of mental foramen in relation to apices of teeth and interdental spaces on the panoramic radiographs. Materials and Methods: The study was done in the Department of Oral Medicine and Radiology, and 750 participants were selected in this study whose radiographic evaluation of mental foramen was done using OPG. The position of the image of the mental foramen was recorded according to criteria given by Wei Cheong Ngeow and Yusof Yuzawati. Statistical Analysis: The collected data were subsequently processed and analyzed using SPSS statistical package version 17. Results: We found that mental foramen is located below the second premolar in 74.4% of the patients followed by between two premolars in 19.3% of the population. In both males and females, most common position was in line with the second premolar followed by between two premolars. The mental foramen was symmetrical in 613 patients (81.7%) and asymmetrical in 137 patients (18.3%). Conclusion: In the present study, it was found that the most common position of the mental foramen was below second premolar followed by between two premolars. It was symmetrical in 81.7% of the population. In males and females, the most common position was below second premolar followed by between two premolars.
Point-Spread Function (PSF) modelling offers the capability to account for resolution degrading p... more Point-Spread Function (PSF) modelling offers the capability to account for resolution degrading phenomena within the PET reconstruction framework. PSF modelling improves resolution and enhances contrast, but at the same time significantly alters image noise properties and induces edge overshoot effect. Thus, studying the effect of PSF modelling on quantitation task performance can be very important. Frameworks explored in the past involve a dichotomy of PSF vs. no-PSF modelling. By contrast, the present work focuses on quantitative performance evaluation of standard uptake value (SUV) PET images, while incorporating a wide spectrum of PSF models, including those that under- and over-estimate the true PSF, for the potential of enhanced quantitation of standardized uptake values (SUVs). The developed framework first analytically models the true PSF, considering a range of resolution degradation phenomena (including photon non-collinearity, inter-crystal penetration and scattering) as present in data acquisitions with modern commercial PET systems. In the context of oncologic liver FDG PET imaging, we generated 200 noisy datasets per image-set (with clinically realistic noise levels) using an XCAT anthropomorphic phantom with liver tumours of varying sizes. These were subsequently reconstructed using the OS-EM algorithm with varying PSF-modelled kernels. We focused on quantitation of both SUVmean and SUVmax, including assessment of contrast recovery coefficients (CRC), as well as noise-bias characteristics (including both image roughness and coefficient-of-variability (CoV)), for different tumours/iterations/PSF kernels. It was observed that overestimated PSF yielded more accurate contrast recovery for a range of tumours, and typically improved quantitative performance. For a clinically reasonable number of iterations, edge enhancement due to PSF modelling (especially due to over-estimated PSF) was in fact seen to lower SUVmean bias in small tumours. Overall, the results indicate that exactly matched PSF modelling does not offer optimized PET quantitation, and that PSF overestimation may provide enhanced SUV quantitation. Furthermore, generalized PSF modelling may provide a valuable approach for in quantitative tasks such as diagnosis, prognostication and treatment-response assessment.
5-Ethyl-1,3,4-thiadiazole-2-amine have been synthesized by single step reaction. A series of hete... more 5-Ethyl-1,3,4-thiadiazole-2-amine have been synthesized by single step reaction. A series of heterocyclic azodyes were synthesized by coupling 8-hydroxyquinoline, 2,6-diaminopyridine, N,N-dimethyl aniline, 2-napthol and resorcinol with diazotized 5-ethyl-1,3,4-thiadiazol-2-amine in nitrosyl sulphuric acid. These dyes were characterized by UV, IR, 1 H NMR, 13 C NMR, elemental analysis and mass spectrometry for selected dyes. The synthesized compounds were also screened for biological activity.
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