Study of the mechanical properties of a ceramics of orthopedic and dental use

The study of the preparation of ceramics is consisted in sintering a hardened cement, wich is composed of mixture of three calcium phosphates : tetracalcium phosphate (Ca4(PO4)2O), -tricalcium phosphate (-Ca3(PO4)2) and monocalcium phosphate (Ca(H2PO4)2.H2O).After wetting, the cement evolved towards an apatitic phase while hardening. To check the effect of certain factors on the resulting ceramics, a complete central composite design of four variables (liquid/solid ratio, stoichiometric coefficient of monocalcium phosphate, rate of increase in temperature and duration of landing of termpertaure) was set up. The equation of the model and optimal conditions were defined

Synthesis and Antibacterial Study of New Microporous Zinc Phosphate Bioceramics

In a ternary system composed of aluminum phosphate, zinc oxide, and orthophosphoric acid, we have prepared microporous ceramics for orthopedic and dental uses. Firstly, we have prepared the ceramics with uncontrollable porosity by sintering blocs of the zinc phosphate cement drawn from the ternary system. Then, based on a binary system consisted of aluminum phosphate, zinc oxide, and some porogenic additives, we have prepared ceramics with good and homogeneous porosity structure. In the second issue, the preparation is made by a simple mixture of powders. Thus, after homogenization, compaction and sintering at high temperatures, the resulted ceramics developed high mechanical resistances. Besides, antibacterial tests on the ceramics have been conducted and shown good biological performances. The mechanical behavior as well as the biological properties candidate the ceramics to be a good alternative to the hard tissue. Eventually, all preparations are controlled and investigated using several technics such as FTIR, XRD, SEM, TAG-TAD, mechanical test, and an antibacterial activity test

Decolorization of Basic Red 5 in aqueous solution by Advanced Oxidation Process using Fenton’s reagent

Fenton reagent was employed to decolorize the aqueous solution containing a dye (Basic Red 5). The effects of initial FeSO4 concentration, initial dye concentration and initial H2O2 concentration on the decolorization of Basic red 5 were investigated. The decolorization  efficiency increase with the rise of FeSO4 concentration  and  H2O2 concentration. However the decolonization efficiency was decreased with increase of dye concentration. The optimal operation parameters for the Fenton oxidation of Basic Red 5 were  [H2O2]0 = 25.50 mg/L and [Fe2+]0 = 20.00 mg/L for [dye]0 = 45.00 mg/L under acidic conditions at room temperature. Under these conditions, 88.71% decolorization efficiency of dye in aqueous solution was achieved after 30 min of reaction.

Predictive model of biliocystic communication in liver hydatid cysts using classification and regression tree analysis

<p>Abstract</p> <p>Background</p> <p>Incidence of liver hydatid cyst (LHC) rupture ranged 15%-40% of all cases and most of them concern the bile duct tree. Patients with biliocystic communication (BCC) had specific clinic and therapeutic aspect. The purpose of this study was to determine witch patients with LHC may develop BCC using classification and regression tree (CART) analysis</p> <p>Methods</p> <p>A retrospective study of 672 patients with liver hydatid cyst treated at the surgery department "A" at Ibn Sina University Hospital, Rabat Morocco. Four-teen risk factors for BCC occurrence were entered into CART analysis to build an algorithm that can predict at the best way the occurrence of BCC.</p> <p>Results</p> <p><b>I</b>ncidence of BCC was 24.5%. Subgroups with high risk were patients with jaundice and thick pericyst risk at 73.2% and patients with thick pericyst, with no jaundice 36.5 years and younger with no past history of LHC risk at 40.5%. Our developed CART model has sensitivity at 39.6%, specificity at 93.3%, positive predictive value at 65.6%, a negative predictive value at 82.6% and accuracy of good classification at 80.1%. Discriminating ability of the model was good 82%.</p> <p>Conclusion</p> <p>we developed a simple classification tool to identify LHC patients with high risk BCC during a routine clinic visit (only on clinical history and examination followed by an ultrasonography). Predictive factors were based on pericyst aspect, jaundice, age, past history of liver hydatidosis and morphological Gharbi cyst aspect. We think that this classification can be useful with efficacy to direct patients at appropriated medical struct's.</p

Retaining Participants in Community-Based Health Research: A Case Example on Standardized Planning and Reporting

Background Effective strategies for participant retention are critical in health research to ensure validity, generalizability and efficient use of resources. Yet standardized guidelines for planning and reporting on retention efforts have been lacking. As with randomized controlled trial (RCT) and systematic review (SR) protocols, retention protocols are an opportunity to improve transparency and rigor. An RCT being conducted in British Columbia (BC), Canada provides a case example for developing a priori retention frameworks for use in protocol planning and reporting. Methods The BC Healthy Connections Project RCT is examining the effectiveness of a nurse home-visiting program in improving child and maternal outcomes compared with existing services. Participants (N&thinsp;=&thinsp;739) were girls and young women preparing to parent for the first time and experiencing socioeconomic disadvantage. Quantitative data were collected upon trial entry during pregnancy and during five follow-up interviews until participants’ children reached age 2 years. A framework was developed to guide retention of this study population throughout the RCT. We reviewed relevant literature and mapped essential retention activities across the study planning, recruitment and maintenance phases. Interview completion rates were tracked. Results Results from 3302 follow-up interviews (in-person/telephone) conducted over 4 years indicate high completion rates: 90% (n&thinsp;=&thinsp;667) at 34&thinsp;weeks gestation; and 91% (n&thinsp;=&thinsp;676), 85% (n&thinsp;=&thinsp;626), 80% (n&thinsp;=&thinsp;594) and 83% (n&thinsp;=&thinsp;613) at 2, 10, 18 and 24 months postpartum, respectively. Almost all participants (99%, n&thinsp;=&thinsp;732) provided ongoing consent to access administrative health data. These results provide preliminary data on the success of the framework. Conclusions Our retention results are encouraging given that participants were experiencing considerable socioeconomic disadvantage. Standardized retention planning and reporting may therefore be feasible for health research in general, using the framework we have developed. Use of standardized retention protocols should be encouraged in research to promote consistency across diverse studies, as now happens with RCT and SR protocols. Beyond this, successful retention approaches may help inform health policy-makers and practitioners who also need to better reach, engage and retain underserved populations

Study of the mechanical properties of a ceramics of orthopedic and dental use

International audienceThe study of the preparation of ceramics is consisted in sintering a hardened cement, wich is composed of mixture of three calcium phosphates : tetracalcium phosphate (Ca4(PO4)2O), -tricalcium phosphate (-Ca3(PO4)2) and monocalcium phosphate (Ca(H2PO4)2.H2O).After wetting, the cement evolved towards an apatitic phase while hardening. To check the effect of certain factors on the resulting ceramics, a complete central composite design of four variables (liquid/solid ratio, stoichiometric coefficient of monocalcium phosphate, rate of increase in temperature and duration of landing of termpertaure) was set up. The equation of the model and optimal conditions were defined