Synthesis and thermal degradation studies of melamine formaldehyde resins.

Melamine formaldehyde (MF) resins have been synthesized at different reaction temperature and pH values. Different molar ratios of melamine and formaldehyde were used to synthesize the corresponding resins. The prepared resin samples were characterized by using molecular weight determination viscometry and thermogravimetric analysis (TGA). The maximum percentage of solid content (69.7%) was obtained at pH 8.5 and 75°C temperature. The molecular weight of MF resin was increased with an increase of melamine monomer concentration. The highest residual weight 14.125 wt.% was obtained with sample 10.

Analytical study to effects on reflection coefficient of Ti-Mn alloys at increasing concentration Mn element in the dental implants application.

Manganese (Mn) is one of the trace elements in the human body, The titanium-manganese (TiMn) alloys have been used in some applications as well. The TiMn alloys with various manganese contents ranging from 2 to 12 wt % were prepared by using mechanical alloying and spark plasma sintering (SPS) techniques (Sibum, 2003). This paper investigated the effects of increasing manganese content in the Ti. Concentrations of Mn (2 wt % to 12 wt %) in titanium influence the reflection coefficients and acoustic signatures of Ti-Mn alloys by Scanning Acoustic Microscopy (SAM) technique, was determined by The oscillatory behavior, The spectral treatment of these signatures, via fast Fourier transform. Correspond to longitudinal and Rayleigh relations depend on Mn Concentrations, was Concluded that Mn Concentrations (from 2 wt % To 12 wt %) increase with increasing Bulk physical properties and Acoustic wave velocities (AWV) as Young's Modulus, Shear Modulus, Bulk modulus, Longitudinal Velocity, Transverse Velocity, and Rayleigh Velocity were (from 105 To 122)Gpa, (from 39.6 To 45.9)Gpa, (from 103 To 119.6)Gpa, (from 4862 To 6183) ms1, (from 2450 To 3115)ms-1and (from 1658 To 2064)ms-1 respectively.

Association between periodontitis and systemic inflammation in patients with end-stage renal disease.

UNLABELLED: Patients with end-stage renal disease (ESRD) experience a significantly increased rate of atherosclerotic complications. Inflammation plays a central role in the pathogenesis of these complications and C-reactive protein (CRP) has been found to be predictive of all-cause and cardiovascular mortality. Many patients have elevated CRP levels without an apparent infection. Periodontal diseases in the general population have been associated with both an increased prevalence of atherosclerotic complications and an elevation in serum CRP values. This study examined the association between periodontal disease and elevated CRP in patients with ESRD on chronic dialysis. METHODS: Eighty patients on chronic dialysis were included in the study. Demographic information, medical history and CRP levels were recorded. Periodontal examination was carried out by a single calibrated examiner and included gingival index (GI), bleeding on probing (BoP), probing depths (PD) and clinical attachment loss (CAL). These measurements were recorded in relation to the Ramfjord teeth. The presence in any one sextant of PD > or =4 mm or clinical loss of attachment > or =3 mm was diagnosed as periodontitis. RESULTS: Mean age of subjects was 50.3 +/- 9.06 years with a median time on dialysis of 24 months. 57.5% (n=46) of subjects were diagnosed as having periodontitis; of these 52.2% had CRP levels >10 mg/l. Of the 34 subjects with healthy periodontium, only 10 (29.4%) had elevated CRP levels. The serum CRP levels between these two groups were significantly different (p = 0.004). CONCLUSION: The results of the study showed significantly elevated levels of CRP in ESRD patients with periodontitis. Periodontal diseases may be an overlooked source of inflammation in ESRD patients.