Interrogating Indian nationalism in the postcolonial context

Nationalism in India, as we see from the wheel in the centre of the flag, and as we know from the story of Gandhi, has been constructed partly on the economics and symbolism of textiles. Emma Tarlo has catalogued the development of ‘national dress’, and state governments in India enshrine certain kinds of textile production as national culture by propping up handloom co-operatives. This text of identity and cloth has become so accepted that Dipesh Chakrabarty now reports we can tell a politician on the make by his hypocritically rigorous adherence to khaddar wear. Such a national text/ile overlooks a different story of cloth in one non-British colony, India. Its politics reveal how, nationally, the symbolism of Gandhian homespun has masked the perpetuation of caste discrimination

Microstructure, mechanical performance and corrosion properties of base metal solder joints

Context: Alloys have been considered to be of paramount importance in the field of prosthodontics. Long span prosthesis may often require joining of one or more individual castings to obtain better fit, occlusal harmony and esthetics in comparison to one-piece casting. Aim: This study was undertaken to evaluate the mechanical properties of base metal alloys joined by two different techniques, namely, gas oxygen torch soldering and laser fusion, compared to a one-piece casting. Mechanical properties evaluated were tensile strength, percentage of elongation and hardness of the solder joint. In addition, corrosion properties and scanning electron microscopic appearance of the joints were also evaluated. Materials and Methods: The samples were prepared according to American Society for Testing Materials specifications (ASTM, E8). Specimens were made with self-cure acrylic and then invested in phosphate-bonded investment material. Casting was done in induction casting machine. Thirty specimens were thus prepared for each group and compared with 30 specimens of the one-piece casting group. Statistical Analysis Used: SPSS software (version 10.0, Chicago, IL, USA) was used for statistical analysis. ANOVA and Benferroni post hoc tests were done for multiple comparisons between the groups and within the groups for mean difference and standard error. Results: Results showed that tensile strength of the one-piece casting was higher than laser fused and gas oxygen torch soldered joints. Laser fused joints exhibited higher hardness values compared to that of gas oxygen torch soldered joints. Scanning electron microscopic examination revealed greater porosity in the gas oxygen torch soldered joints. This contributed to the reduction in the strength of the joint. Gas oxygen torch soldered joints showed less corrosion resistance when compared to laser fused joints and one-piece casting. Conclusion: Laser fusion, which is a recent introduction to the field of prosthodontics, produces joints which have properties between those of one-piece casting and the gas oxygen torch soldering

Evaluation of marginal gap of Ni-Cr copings made with conventional and accelerated casting techniques

Context: Conventional casting techniques following the manufacturers′ recommendations are time consuming. Accelerated casting techniques have been reported, but their accuracy with base metal alloys has not been adequately studied. Aim: We measured the vertical marginal gap of nickel-chromium copings made by conventional and accelerated casting techniques and determined the clinical acceptability of the cast copings in this study. Settings and Design: Experimental design, in vitro study, lab settings. Materials and Methods: Ten copings each were cast by conventional and accelerated casting techniques. All copings were identical, only their mold preparation schedules differed. Microscopic measurements were recorded at ×80 magnification on the perpendicular to the axial wall at four predetermined sites. The marginal gap values were evaluated by paired t test. Results: The mean marginal gap by conventional technique (34.02 μm) is approximately 10 μm lesser than that of accelerated casting technique (44.62 μm). As the P value is less than 0.0001, there is highly significant difference between the two techniques with regard to vertical marginal gap. Conclusion: The accelerated casting technique is time saving and the marginal gap measured was within the clinically acceptable limits and could be an alternative to time-consuming conventional techniques

Evaluation of the effect of titanium dioxide and gold nanoparticles surface treatment on the flexural strength of polymethyl methacrylate heat cure denture base resin

Aim: The purpose of this study was to evaluate the effect of Titanium dioxide and Gold nanoparticles surface treatment on the flexural strength of Polymethyl methacrylate (PMMA) Heat cure denture base resins.Materials and methods: A total of thirty PMMA Heat cure denture base resin test samples were fabricated of size 65 x 10 x 2.5 mm (rectangular shaped) according to ADA specification no.2. The samples were divided into three groups as Conventional PMMA heat cure denture base resin samples (GROUP I, n = 10 CONTROL), PMMA Heat cure denture base resin samples coated with Titanium dioxide nanoparticles (GROUP II, n = 10) and PMMA Heat cure denture base resin samples coated with Gold nanoparticles (GROUP III, n = 10). GROUP II and GROUP III PMMA Heat cure denture base resin test samples were coated by Magnetron sputtering. Flexural strength of GROUP I, GROUP II and Group III was evaluated by a three-point bend test using a Universal testing machine and the mean values were obtained.Results: The Mean flexural strength of GROUP I, GROUP II and GROUP III samples were 114.79 MPa, 142.48 MPa and 154.70 MPa respectively. On comparative evaluation of the flexural strength among the three groups GROUP III PMMA Heat cure denture base resin samples exhibited the highest flexural strength followed by GROUP II and least by GROUP I. The statistical analysis by ANOVA had shown that there is significance in flexural strength among the groups tested (p - value = 0.000*).Conclusion: Within the limitations of the study, PMMA heat cure denture base resin coated with Gold nanoparticles showed the highest flexural strength followed by PMMA Heat cure denture base resin coated with Titanium dioxide nanoparticles. Conventional PMMA Heat cure denture base resin without any surface treatment showed the least flexural strength

Comparative evaluation of the effect of electrolyzed oxidizing water on surface detail reproduction, dimensional stability and Surface texture of poly vinyl siloxane impressions

Aim: The aim of this in vitro study was to comparatively evaluate the effect of chemical disinfectants on the surface detail reproduction, dimensional stability and surface texture of polyvinyl siloxane (PVS) impressions. Materials and Methods: The impressions were then divided into five groups (fifteen samples per group) and subjected to a ten minutes immersion with 2% glutaraldehyde (Group I), 1% sodium hypochlorite (Group II), freshly prepared electrolyzed oxidizing water (EOW) with different pH values - acidic (Group III), alkali (Group IV) and neutral (Group V). The samples were examined pre and post-immersion under visual observation for surface detail reproduction, travelling microscope for measurement of dimensional stability and surface profilometer (3D) for evaluation of surface texture. A standardized master die was fabricated and seventy-five PVS test samples were made. The samples were subjected to immersion disinfection and studied for surface detail reproduction, dimensional stability and surface texture. Post-hoc test, paired t test and ANOVA were used to analyze dimensional stability statistically both within and between the test groups. Results: The surface detail reproduction was satisfactory with both pre and post-immersion test samples. A statistically significant dimensional change was observed post-immersion in Groups II, III and V test samples and a statistically insignificant dimensional change was observed in Groups I and IV test samples. There was a negligible change in surface texture post-immersion in Groups I, III, IV and V test samples with a slight increase in surface roughness post-immersion in Group II samples. Conclusion: In this study, all the test disinfectants produced satisfactory surface detail reproduction on Polyvinyl siloxane impressions. 2% glutaraldehyde and electrolyzed oxidizing water (alkali) have resulted in statistically insignificant dimensional change, while 1% sodium hypochlorite, electrolyzed oxidizing water (acidic) and electrolyzed oxidizing water (neutral) have resulted in statistically significant dimensional changes. All the test disinfectants except 1% sodium hypochlorite showed a reduction in surface roughness (Ra) values