Greater severity and extent of periodontal breakdown in 136 south Indian human immunodeficiency virus seropositive patients than in normal controls: a comparative study using community periodontal index of treatment needs

Apart from the more or less distinctive forms of periodontal disease associated with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome there remains considerable uncertainty as to whether or not conventional destructive periodontitis is exacerbated in HIV positive individuals. This is especially so in developing countries, from which few studies have been reported. The present study compared the severity and extent of periodontal break down in 136 HIV positive individuals from Chennai, South India, with 136 age-matched controls from the same low socio-economic and ethnic group. All surfaces of all teeth were scored for the community periodontal index of treatment needs (CPITN). Statistical analysis was performed using SPSS package. The results of the present study show that CPITN is a simple, useful technique to assess periodontal status in immunosuppressed patients and that periodontitis is associated with immunosuppression and oral candidiasis. The assessment of periodontal statuscould thus be a useful tool in minimally invasive screening of populations for HIV disease, especially in those parts of the world, like India and Africa, with high prevalence and rising incidence.

Vaporization thermodynamic studies by high-temperature mass spectrometry on some three-phase regions over the MnO-TeO2 binary line in the Mn-Te-O ternary system

Knudsen effusion mass spectrometric measurements have been performed in the temperature range of 850-950 K over four three-phase mixtures, each phase mixture having at least one phase lying on the MnO-TeO2 binary line of the Mn-Te-O phase diagram, and the rest of the phases lying above this binary line. The three-phase mixtures investigated are Mn3O4 + MnO + Mn6Te5O16; Mn3O4 + Mn6Te5O16 + MnTeO3; Mn3O4 + Mn3TeO6 + MnTeO3; and Mn3TeO6 + MnTeO3 + Mn2Te3O8. The vapor pressures of the gaseous species TeO2, TeO, and Te2 over these three-phase mixtures were measured, and various heterogeneous solid-gas reactions were evaluated along with the homogeneous gas-phase reaction TeO2(g) + 0.5Te2(g) = 2 TeO(g). The enthalpy and Gibbs free energy of formation of the four ternary Mn-Te-O phases were deduced at T = 900 K. These values (in kJ.mol-1), along with the estimated uncertainties in them are Delta(f)H(o)m = 4150 +/- 19, 752 +/- 11, 1710 +/- 11, 1924 +/- 40, and Delta(f)G(o)m= 2835 +/- 28, 511 +/- 11, 1254 +/- 19, 1238 +/- 38, for Mn6Te5O16, MnTeO3, Mn3TeO6, and Mn2Te3O8, respectively. A thermochemical assessment was made to examine the conditions under which the ternary Mn-Te-O phases could be formed on a stainless steel clad of mixed-oxide-fueled (MO2; M = U + Pu) fast breeder nuclear reactors. The phase Mn3TeO6 could be formed when the fuel is even slightly hyperstoichiometric (O/M = 2.0002) and the phase Mn6Te5O16 could also be formed when O/M = 2.0004. The threshold tellurium potential for the formation of Mn3TeO6 is higher than that for MnTe0.80 and CrTe1.10, but is comparable to that for MoTe1.10, and even lower than that for FeTe0.81 or NiTe0.63.