HYDRATION CHARACTERISTICS OF PROMPT CEMENT IN THE PRESENCE CITRIC ACID AS RETARDER

The aim of the present work is to study the influence of citric acid (CA) as retarder on the properties of prompt cement pastes. The dosages of CA were 0.50, and 0.75, 1.00 and 1.25 mass % of prompt cement. The initial and final setting times, bulk density, compressive strength, total porosity, and hydration kinetics such as free lime, combined water contents and XRD for selected sample were investigated. The results obtained in this study showed that the addition of CA elongates the initial and final setting times and decreases the compressive strength and combined water contents, whereas, it increases the total porosity at all ages of hydration. CA retards the liberation of Ca(OH)2 of prompt pastes. The free lime contents of prompt cement pastes are slightly increased up to 28 days then sharply increased up to 90 days. Thus, it is suggested that citrate sorbed onto the clinker surface and formed a protective layer around the clinker grains retarding their dissolution. The sharp increase of compressive strength at later ages after 28 days up to 90 days. The presence of 0.75 mass % citric acid achieves the initial and final setting time of the prompt cement according to the ASTM specification

Signature of real-time PCR in detection of Trichomonas vaginalis infection and its association with human papillomavirus genotype 16

OBJECTIVE: Infection with Trichomonas vaginalis (TV) is the most prevalent non-viral sexually transmitted infection in the world. The objective of the study was to investigate the incidence of TV infection and its association with Human Papillomavirus (HPV) in a sample of Egyptian females. PATIENTS AND METHODS: 96 Egyptian females suspected for trichomoniasis were involved in our study. Vaginal washouts and cervical (cytobrush) samples were obtained from all patients and examined for T. vaginalis by direct wet mount, modified Diamond’s culture medium, and real-time PCR. Cervical (cytobrush) samples were examined for HPV using real-time PCR. RESULTS: Out of 96 patients, 28 (29%) was positive for T. vaginalis by real-time PCR. HPV was detected in 33 patients (34.4%); 31 cases (32.3%) were infected with HPV of genotype 16, whereas only two cases (2.1%) had genotype 18 infection. A significant association was found between TV and HPV infection [Odds ratio (OR)=10.58; 95% confidence interval (CI): 3.819 - 29.29; p<0.001]. CONCLUSIONS: When it comes to diagnosing trichomoniasis in a susceptible population, real-time PCR is more reliable than traditional standard approaches. A significant association between TV and HPV infection was found. Further research into the processes by which these two organisms interact at the cellular level could be revealed