Design, development, and instrumentation of isopiestic experimental setup.

An isopiestic experimental facility for the measurement of vapor pressures has been designed, fabricated, and commissioned. Using the vapor pressure data as a function of temperature, useful thermodynamic properties of alloys and compounds of interest can be derived. The isopiestic facility comprises a pair of furnaces, temperature controllers, thermocouple movement mechanism, user interface, and data collection. Four such experimental setups have been commissioned. This experimental facility is useful to determine the vapor pressures of a volatile component over the condensed phases as a function of temperature and composition. Using the vapor pressure data, the thermodynamic properties of various systems can be determined. The experimental setup was validated by a Pr-Cd isopiestic run, and the results are compared with the data reported in the literature.

A Comparative Evaluation of Bifidobacteria Levels in Early Childhood Caries and Severe Early Childhood Caries.

BACKGROUND: Bifidobacteria levels in saliva were found to be significantly correlated in adults with dental caries but less information available in the literature regarding its role in children. AIM: The aim is to compare the salivary levels of Bifidobacteria in children who are caries free with that of early childhood caries (ECC) and severe ECC (S-ECC). MATERIALS AND METHODS: Saliva was collected using the tongue-loop method from a total of 60 children between the age group of 3-5 years and they were further divided into 3 groups. In addition, the age and gender of the children, sugar amount in diet, sugar frequency in diet, were recorded. RESULTS: Bifidobacteria was isolated from all the three groups, but more were from S-ECC, followed by ECC and very few cases of caries-free children and was found to statistically significant (P < 0.001). Salivary levels of Bifidobacteria were significantly correlated with amount of sugar in the diet and frequency of sugar consumption. CONCLUSIONS: Salivary levels of Bifidobacteria were significantly associated with S-ECC and ECC, followed by caries free group. In future, it can be used as a salivary marker for caries risk assesment.

Enhanced Structural and Magnetic Coupling in a Mesocrystal-Assisted Nanocomposite.

Benefiting from the advances made in well-controlled materials synthesis techniques, nanocomposites have drawn considerable attention due to their enthralling physics and functionalities. In this work, we report a new heteroepitaxial mesocrystal-perovskite nanocomposite, (NiFe2O4)0.33:(La0.67Ca0.33MnO3)0.67. Elaborate structural studies revealed that tiny NiFe2O4 nanocrystals aggregate into ordered octahedral mesocrystal arrays with {111} facets together with a concomitant structural phase transition of the La0.67Ca0.33MnO3 matrix upon postannealing process. Combined magnetic and X-ray absorption spectroscopic measurements show significant enhancement in the magnetic properties at room temperature due to the structural evolution of magnetic NiFe2O4 and the consequent magnetic coupling at the heterointerfaces mediating via well connected octahedrons of Mn-O6 in La0.67Ca0.33MnO3 and (Ni,Fe)-O6 in NiFe2O4. This work demonstrates an approach to manipulate the exciting physical properties of material systems by integrating desired functionalities of the constituents via synthesis of a self-assembled mesocrystal embedded nanocomposite system.

Knowledge, attitude, and perception of mothers towards emergency management of dental trauma in Salem district, Tamil Nadu: a questionnaire study.

BACKGROUND: Dental trauma is one of the main oral health problems in childhood, and can cause pain and distress. It is important to provide emergency care to combat the aftermaths of trauma. AIM: The aim of the study is to assess the knowledge and attitude of mothers regarding dental trauma and its management. MATERIALS AND METHODS: A questionnaire consisting of 33 closed-ended questions were used to interview 150 mothers who participated in the study. The questions assessed the knowledge and attitude of mothers towards their child's dental visit, dental trauma, and its management. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS) version 17.0. RESULTS: Mother's previous experience of dental trauma when associated with the preservation of avulsed tooth of the child, those mothers who had the experience of dental trauma reported that they would discard the tooth which was found to be statistically significant (P < 0.05) when compared to the mothers with no experience of trauma. The education status of the study population when associated with the knowledge variables of avulsion, it was found that most of the variables had statistically significant association with P < 0.05. CONCLUSION: This study reveals that there is a lack of awareness among the mothers regarding the emergency management of dental trauma. This warrants the need of an effective communication between dental professionals and mothers for better handling of dental emergencies.

Identifying sexual dimorphism in a paediatric South Indian population using stepwise discriminant function analysis.

Anthropological research relies on skeletal and dental remains for the identification of species. Sexual dimorphism is the systematic difference in form between males and females of the same species. This study is designed to compute a new formula for sex determination using discriminant function analysis in the deciduous crown dimensions of a paediatric population of South Indian origin and to check its accuracy. The sample consisted of 93 females and 90 males of South Indian origin aged between 5 and 13 years. Alginate impressions of the upper dental arch were made and casts were poured immediately. A digital vernier calliper was used to obtain measurements. Teeth considered for measurement were deciduous maxillary canines and molars. Our study is a maiden attempt in considering diagonal measurements along with mesiodistal (MD) and buccolingual (BL) dimensions as predictor variables for sex determination. Statistical analysis was performed using the Statistical Package for the Social Science version 17.0 software. By using the Student t-test, the different predictor variables of teeth selected between male and females were found to be significant (p < 0.05). Highly significant sexual dimorphism was found in the mean MD dimension of maxillary right canine and right and left first molar, BL dimension of right first molar, distobuccal-mesiolingual of right and left first molar and right second molar and mesiobuccal-distolingual of right second molar. The percentage of sexual dimorphism in MD dimensions revealed that the right upper first molar was the most dimorphic tooth and the upper first molar of the left side was the least dimorphic of the six teeth studied. The present study found the level of sexual dimorphism in the deciduous crown dimensions of a selected group of South Indian population, which is sufficiently large to determine sex with an accuracy of 87.2-88% by discriminant function analysis. Hence the formula derived from the present study could be of some value in sex determination of paediatric populations of South Indian origin.

Design and adaptation of a novel supercritical extraction facility for operation in a glove box for recovery of radioactive elements.

The design and development of a novel supercritical extraction experimental facility adapted for safe operation in a glove box for the recovery of radioactive elements from waste is described. The apparatus incorporates a high pressure extraction vessel, reciprocating pumps for delivering supercritical fluid and reagent, a back pressure regulator, and a collection chamber. All these components of the system have been specially designed for glove box adaptation and made modular to facilitate their replacement. Confinement of these materials must be ensured in a glove box to protect the operator and prevent contamination to the work area. Since handling of radioactive materials under high pressure (30 MPa) and temperature (up to 333 K) is involved in this process, the apparatus needs elaborate safety features in the design of the equipment, as well as modification of a standard glove box to accommodate the system. As a special safety feature to contain accidental leakage of carbon dioxide from the extraction vessel, a safety vessel has been specially designed and placed inside the glove box. The extraction vessel was enclosed in the safety vessel. The safety vessel was also incorporated with pressure sensing and controlling device.

Growth and characterization of manganese doped gallium nitride nanowires.

Manganese doped GaN nanowires have been grown by chemical vapour transport method on sapphire (0001) substrates in the temperature range of 800-1050 degrees C. The surface features of nanowires have been investigated using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDAX), Raman scattering studies and Electron Paramagnetic Resonance (EPR). SEM images showed that the morphology of the one dimensional materials included straight nanorods and nanowires around 70-80 nm. Raman spectrum showed the GaMnN vibrational modes at 380, 432 and 445 cm(-1). EPR measurements were performed on Mn doped GaN nanowires in order to evaluate the magnetic behaviour.

Effect of fly ash inhalation on biochemical and histomorphological changes in rat lungs.

Effect of respirable fly ash particles inhalation on lungs of rats was investigated by exposing them to respirable aerosols of size classified power plant fly ash at average concentrations of up to 14.4 +/- 1.77 mg/m3 for 4 hr/day for 28 consecutive days. A remarkable increase was found in blood eosinophil counts of fly ash exposed animals. Biochemical indicators of pulmonary damage viz. lactate dehydrogenase (cytoplasmic enzyme used as a measure of cell injury), gamma-glutamyl transferase (Clara cell damage) and alkaline phosphatase (potential measure of Type 11 cell secretions) in broncho alveolar lavage fluid (BALF) of fly ash exposed group showed significant elevation. Clumping of fly ash particles in the lungs was observed as evidenced by fly ash ladened macrophage accumulation in the alveolar region. The results suggest a damage, local inflammation and remodelling of lung as indicated by hypertrophy and hyperplasia. These changes reflect the toxic effects of the fly ash inhalation.