Prevalence and attributes of traumatic dental injuries to anterior teeth among school going children of Kolkata, India.

Background: Traumatic Dental Injuries (TDI) have emerged as a very significant public health and social problem, especially among children and adolescents. The aim of this study was to investigate the prevalence and associated risk factors of traumatic dental injuries to permanent anterior teeth in school going children of Kolkata aged 7-14 years. Method: A cross-sectional study was conducted among 3762 school going children attending various private and public schools of Kolkata aged 7-14 years. A multistage random clustering sampling technique was adopted to select the children.Type of trauma using Ellis and Davey classification of fractures along with Andresen's Epidemiological Classification of Traumatic Injuries to Anterior Teeth, including WHO codes, was used. All values were considered statistically significant at P < 0.05. Results: Prevalence of TDI to anterior teeth was found to be 9.89%. The mean age of children who presented with TDI was 11.06 ± 1.99.years. The most common place of occurrence of TDI was home. Falls were the most common causes of trauma. Children belonging to higher socioeconomic status were observed to have an increased prevalence of TDIs.The highest potential risk factor for the occurrence of trauma was a past history of trauma. Conclusion: Present study found a prevalence of 9.89%, and a very low percentage of children had received treatment.

A crossbar architecture based system (CAS) as hydrogen gas sensing platform.

The development of sensing technologies and miniaturization allows for the development of smart systems with elevated sensing performance. Silicon-based hydrogen sensors have received a lot of attention due to its electrical conductivity and the mechanical endurance. With this motivation, we have proposed a two-terminal silicon-based device in a crossbar architecture as a hydrogen gas sensing platform. In this work, we have adopted a multi-layer modeling approach to analyze the performance of the proposed system. Technology computer-aided design models have been used to capture device performance. A gas sensor model based on hydrogen adsorption on the Palladium surface and a crossbar model has been adopted to understand the Palladium work function variation with gas pressure and the performance of the proposed crossbar system respectively. We have shown the impact of parameters like interconnect resistance and array size on the whole system's performance. Finally, a comprehensive analysis has been provided for the design rule of this architecture. A fabrication process to spur future experimental works has also been added. This work will provide computational insight into the performance of a crossbar hydrogen sensor system, optimized against some critical parameters.

Strong suppression of heat conduction in a laboratory replica of galaxy-cluster turbulent plasmas.

In conventional gases and plasmas, it is known that heat fluxes are proportional to temperature gradients, with collisions between particles mediating energy flow from hotter to colder regions and the coefficient of thermal conduction given by Spitzer's theory. However, this theory breaks down in magnetized, turbulent, weakly collisional plasmas, although modifications are difficult to predict from first principles due to the complex, multiscale nature of the problem. Understanding heat transport is important in astrophysical plasmas such as those in galaxy clusters, where observed temperature profiles are explicable only in the presence of a strong suppression of heat conduction compared to Spitzer's theory. To address this problem, we have created a replica of such a system in a laser laboratory experiment. Our data show a reduction of heat transport by two orders of magnitude or more, leading to large temperature variations on small spatial scales (as is seen in cluster plasmas).

Noise immune dielectric modulated dual trench transparent gate engineered MOSFET as a label free biosensor: proposal and investigation.

We propose and investigate a biosensor based on a transparent dielectric-modulated dual-trench gate-engineered metal-oxide-semiconductor field-effect transistor (DM DT GE-MOSFET) for label-free detection of biomolecules with enhanced sensitivity and efficiency. Various sensing parameters such as the I ON/I OFF ratio and the threshold voltage shift are evaluated as metrics to validate the proposed sensing device. Additionally, S Vth (the V th sensitivity) is also analyzed, considering both positively and negatively charged biomolecules. In addition, radiofrequency (RF) sensing parameters such as the transconductance gain and the cutoff frequency are taken into account to provide further insight into the sensitivity of the proposed device. Furthermore, the linearity, distortion, and noise immunity of the device are evaluated to confirm the overall performance of the biosensor at high (GHz) frequency. The results indicate that the proposed biosensor exhibits a S Vth value of 0.68 for positively charged biomolecules at a very low drain bias of 0.2 V. The proposed device can thus be used as an alternative to conventional FET-based biosensors.

Oral and maxillofacial injuries in children: a retrospective study.

OBJECTIVES: The purpose of this retrospective epidemiological study was to determine the etiology and pattern of maxillofacial injuries in a pediatric population. MATERIALS AND METHODS: Data for pediatric maxillofacial trauma patients aged 12 years and younger who were registered at the Department of Pediatric and Preventive Dentistry, Dr. R. Ahmed Dental College and Hospital, Kolkata, India, were reviewed and examined. Patients who were treated between October 2016 and September 2018 were analyzed according to age, sex, cause of injury, frequency and site of facial fractures, and soft tissue injuries. The chi-square tests were carried out for statistical analyses with a significance level of 5%. RESULTS: Of 232 patients with a mean age of 6.77±3.25 years, there were 134 males (57.8%) and 98 females (42.2%). The overall male to female ratio was 1.39:1. The most common causes of injuries were falls (56.5%) and motor vehicle accidents (16.8%). Incidence of falls decreased significantly with age (P<0.001). Dentoalveolar injuries (61.6%) and soft tissue injuries (57.3%) were more common than facial fractures (42.7%). Mandibular fractures (82.8%) were the most common facial fractures, and perioral or lip injuries were the most prevalent injuries in our patient population. There was a positive association between facial fractures and soft tissue injury (P<0.01) (odds ratio 0.26; confidence interval 0.15-0.46). CONCLUSION: Falls were the leading cause of maxillofacial trauma in our sample of children, and the most common site of fractures was the mandible.

Evaluation of knowledge, awareness, and attitude toward emergency dental trauma management among the school teachers of Kolkata.

INTRODUCTION: Traumatic dental injuries (TDIs) are very common in childhood. Majority of TDI occur at home followed by schools. The prognosis of TDIs to a great extent is dependent on prompt emergency measures taken at the site of accident. Hence, it is of paramount importance to assess the knowledge of people present at the site of accident that generally includes parents, teachers, and sports coaches. AIM OF STUDY: The aim of the study was to assess the knowledge, attitude, and awareness of school teachers of Kolkata regarding management of TDIs. MATERIALS AND METHODS: A cross-sectional survey was conducted on 400 school teachers of Kolkata over a period of 2 months using a pretested close-ended questionnaire. The questionnaire had three parts: Part 1 contained questions on personal information, Part 2 contained questions based on two imaginary cases of trauma, and Part 3 related to their attitude toward dental trauma education. Chi-square test was done to describe the strength of the associations. RESULTS: The overall knowledge of school teachers regarding management of TDIs was not found to be satisfactory. It was observed that most of the teachers were in favor of taking immediate professional consultation for the emergency management, but most of them were unaware of the steps to be taken on their part to minimize complications and improve prognosis. CONCLUSION: Despite the lack of knowledge and awareness regarding management of dental trauma, school teachers of Kolkata had a good attitude toward management of dental trauma and its education.

Distance M-Me: A novel parameter having significant potential as a predictor of mandibular growth.

OBJECTIVES: The purpose of the present study was to investigate the relationship of the measured distance between two mandibular points (distance M-Me) to chronological age and to find out whether the absolute values of distance M-Me could be classified age-wise into a unique range, which could be directly read for predicting the stage of mandibular growth. METHODS AND MATERIALS: The study sample consists of lateral cephalometric records of 65 patients (34 females and 31 males; age range: 6-21 years). Chronological age was calculated in decimal years. Lateral cephalograms were assessed by two independent examiners. Points M and Me were located on the lateral cephalograms, and linear distance between them was measured. RESULTS: Pearson product-moment correlation coefficients showed a high correlation between chronological age and distance M-Me (0.746 for females and 0.869 for males, p < 0.01). When the values of distance M-Me were compared with chronological age, it was possible to make four age groups (for females and males separately), where each group showed a unique range of value for distance M-Me. The values increased with increasing age. CONCLUSIONS: Increase in value of distance M-Me with age, showing reduced individual variation, depicts a well-conserved linear dimension. Values of distance M-Me can be directly read for predicting the stage of mandibular growth and can be used as a valuable adjunct or substitute to chronological age.

Tricho-dento-osseous syndrome and precocious eruption.

Tricho-dento-osseous syndrome (TDO), an uncommon form of ectodermal dysplasia is an autosomal dominant genetic disorder which is characterized by inherited defects in tissues arising from epithelial-mesenchymal interaction. Genetic studies have revealed that it is caused by mutation in the DLX3 gene. TDO presents with a great phenotypic heterogeneity and studies have suggested that this heterogeneity is the result of environmental factors or other genetic modifiers. In this article, we report a case of TDO in which the child had typical clinical features of hair, teeth and bone defects, as seen in TDO. Parents of the child were unaffected. Genetic analysis of the child revealed mutation in DLX3 gene. The child also showed precocious eruption of the permanent molars, a clinical feature which has been rarely reported. We suggest that the precocious eruption seen in TDO is probably due to a markedly increased osteoblastic activity. Key words:Tricho-dento-osseous syndrome, DLX3 gene, precocious eruption.

Clinical Measurement of Maximum Mouth Opening in Children of Kolkata and Its Relation with Different Facial Types.

INTRODUCTION: Maximal opening of mouth is described as the greatest distance between incisal edge of maxillary central incisor to the incisal edge of mandibular central incisor, when the mouth is opened as wide as possible painlessly or as the inter incisal distance plus the overbite. Clinical measurement of normal range of Maximum Mouth Opening (MMO) in children is an important diagnostic criterion for evaluation of stomatognathic system, especially for those with temporomandibular and neurogenic dysfunctions. AIM: To determine the correlation of maximal mouth opening with age, sex, height, body weight and different facial types. MATERIALS AND METHODS: The study was a cross-sectional study which was conducted on 434 children, who were randomly divided into three groups based on their age: Group I- children of age 6 to 8 years, Group II- children of age 8.1 to 10 years, Group III- children of age 10.1 to 12 years. For each child, the examiner took three readings of MMO in millimeters (mm) and the mean of the three readings was considered. Age, sex, standing height, body weight and facial type of each child were also recorded simultaneously. Pearson correlation was used to determine the relationship between the different parameters. p-value <0.05 was the bench mark for statistical significance in the analysis. Descriptive and inferential analysis was done for the data using SPSS version 20.0. (SPSS 20, inc.; Chicago). RESULTS: The estimated average MMO measured for girls and boys in the age range of 6-8 years, with a total sample size of 139, was 41.14 ± 4.29 mm and 42.16 ± 3.98mm respectively in euryprosopic face type. In leptoproscopic face type, it was 42.12 ± 4.54mm and 43.76 ± 3.80 mm in girls and boys respectively. In mesoproscopic face type, MMO measured was 41.77 ± 4.09mm and 42.51 ± 3.95 mm in girls and boys respectively. The estimated average MMO measured for girls and boys in the age range of 8.1-10 years, with a total sample size of 143, was 44.42+4.69mm and 43.30 ± 4.11 mm in euryprosopic face type. In leptoproscopic face type, it was 43.02 ± 3.92mm and 46.29 ±3.09mm in girls and boys respectively. In mesoproscopic face type, MMO measured was 42.50 ±4.32 and 42.80 ± 5.16 mm in girls and boys respectively. The estimated average MMO measured for girls and boys in the age range of 10.1-12 years, with a total sample size of 152, was 44.63 ± 5.28 mm and 45.80 ± 5.18 mm respectively in euryprosopic face type. In leptoproscopic face type, it was 45.76 ± 4.98 mm and 46.28 ± 4.68 mm in girls and boys respectively. In mesoproscopic face type, MMO measured was 45.32 ± 5.80 mm and 46.03 ± 5.86 mm in girls and boys respectively. CONCLUSION: There was a significant difference in MMO between males and females; with males having higher values in all age groups. MMO is seen to increase with age in a statistically significant manner. Significantly increased value of MMO was observed in leptoproscopic face type in comparison to euryproscopic and mesoproscopic face type for each age group.

Evidence of scaling in the high pressure phonon dispersion relations of some elemental solids.

First principles searches are carried out for the existence of an asymptotic scaling law for the zero temperature phonon dispersion relation of several elemental crystalline solids in the high pressure regime. The solids studied are Cu, Ni, Pd, Au, Al, and Ir in the face-centered-cubic (fcc) geometry and Fe, Re, and Os in the hexagonal-close-packed (hcp) geometry. At higher pressures, the dependence of the scale of frequency on pressure can be fitted well by a power law. Elements with a given crystalline geometry have values of the scaling exponent very close to each other (0.32 for fcc and 0.27 for hcp - with a scatter below five percent of the average).

Wang-Landau density of states based study of the folding-unfolding transition in the mini-protein Trp-cage (TC5b).

We present the results of a high-statistics equilibrium study of the folding/unfolding transition for the 20-residue mini-protein Trp-cage (TC5b) in water. The ECEPP/3 force field is used and the interaction with water is treated by a solvent-accessible surface area method. A Wang-Landau type simulation is used to calculate the density of states and the conditional probabilities for the various values of the radius of gyration and the number of native contacts at fixed values of energy--along with a systematic check on their convergence. All thermodynamic quantities of interest are calculated from this information. The folding-unfolding transition corresponds to a peak in the temperature dependence of the computed specific heat. This is corroborated further by the structural signatures of folding in the distributions for radius of gyration and the number of native contacts as a function of temperature. The potentials of mean force are also calculated for these variables, both separately and jointly. A local free energy minimum, in addition to the global minimum, is found in a temperature range substantially below the folding temperature. The free energy at this second minimum is approximately 5 k(B)T higher than the value at the global minimum.

Fermi gamma-ray "bubbles" from stochastic acceleration of electrons.

Gamma-ray data from Fermi Large Area Telescope reveal a bilobular structure extending up to ∼50° above and below the Galactic Center. It has been argued that the gamma rays arise from hadronic interactions of high-energy cosmic rays which are advected out by a strong wind, or from inverse-Compton scattering of relativistic electrons accelerated at plasma shocks present in the bubbles. We explore the alternative possibility that the relativistic electrons are undergoing stochastic 2nd-order Fermi acceleration by plasma wave turbulence through the entire volume of the bubbles. The observed gamma-ray spectral shape is then explained naturally by the resulting hard electron spectrum modulated by inverse-Compton energy losses. Rather than a constant volume emissivity as in other models, we predict a nearly constant surface brightness, and reproduce the observed sharp edges of the bubbles.

Asymmetric dark matter and the sun.

Cold dark matter particles with an intrinsic matter-antimatter asymmetry do not annihilate after gravitational capture by the Sun and can affect its interior structure. The rate of capture is exponentially enhanced when such particles have self-interactions of the right order to explain structure formation on galactic scales. A "dark baryon" of mass 5 GeV is a natural candidate and has the required relic abundance if its asymmetry is similar to that of ordinary baryons. We show that such particles can solve the "solar composition problem." The predicted small decrease in the low energy neutrino fluxes may be measurable by the Borexino and SNO+ experiments.

Testing astrophysical models for the PAMELA positron excess with cosmic ray nuclei.

The excess in the positron fraction measured by PAMELA has been interpreted as due to annihilation or decay of dark matter in the Galaxy. More prosaically it has been ascribed to direct production of positrons by nearby pulsars or due to pion production during diffusive shock acceleration of hadronic cosmic rays in nearby sources. We point out that measurements of secondary cosmic ray nuclei can discriminate between these possibilities. New data on the titanium-to-iron ratio support the hadronic source model above and enable a prediction for the boron-to-carbon ratio at energies above 100 GeV.

Coexistent partial anodontia and supernumerary tooth in the mandibular arch: a rare case.

Coexistent partial anodontia and supernumerary tooth in the lower jaw is a very uncommon condition. Very few cases have been reported in the literature of this condition, etiology of which is still obscure. Presented here is a rare case of simultaneous presence of single supernumerary tooth together with missing permanent central incisor teeth in the lower jaw without any associated systemic condition or syndrome.

Universality in the vibrational spectra of single-component amorphous clusters.

We have numerically investigated the vibrational spectra of amorphous single-component clusters for several types of interactions among the particles. For all the potentials we have studied, we find that the density of states can be described, except at the two ends of the spectrum, by the same functional form to a very good approximation, and that the fluctuation properties of the spectra in this central region converge to those of the Gaussian orthogonal ensemble of random matrices with increasing system size. We conjecture that this scenario is true for a broad class of potentials.