Structural and electronic properties of BiOF with two-dimensional layered structure under high pressure: Ab initio study

WOS: 000454538900007In this work, the crystal structure of the BiOF is studied under high hydrostatic pressure using ab initio calculations. Pressure-volume relationships and structural transitions are investigated using Siesta method. A first-order phase transition from the tetragonal matlockite PbFCl-type structure with space group P4/nmm to the orthorhombic structure with space group Cmcm is successfully observed for BiOF. This phase transition which occur around 19.6 GPa is also analyzed from the total energy and enthalpy calculations. In addition, electronic properties of BiOF are researched during the pressure. By analyzing the energy band structures, it is found that the band gaps P4/nmm and Cmcm phases for the BiOF are 2.74 and 2.47 eV, respectively

Mandibular Condyle Fractures and Treatment Modalities

Maxillofacial injuries are most commonly associated with falls, motor and vehicle accidents, sports-related trauma, and interpersonel violence. The complexity of mandibular condyle region and its anatomic proximity to other craniofacial structures complicate diagnosis and treatment. Thus, treatment approaches of mandibular condyle fracture are still controversial. In the literature, different success rates are reported about observation versus treatment, closed reduction versus open reduction and fixation methods. In the present article, controversial issues related to mandibular condyle fractures were reviewed under the light of current literature. In conclusion, the simplest way that can be done with the least risk of complication should be chosen during treatment planning. In addition, current adjunctive treatment methods accelerating healing of fracture should be considered. [Archives Medical Review Journal 2014; 23(4.000): 658-671

Disturbance/Uncertainty Estimator Based Integral Sliding-Mode Control

A disturbance/uncertainty estimator based integral sliding-mode control approach is introduced. Explicit mathematical expressions for robust stability, performance, and bandwidth requirement are derived. The integral sliding-mode controller is built to satisfy certain industrial criteria. It is integrated into the robustness analysis via its quasi-linear representation. The proposed methodology is experimentally verified on a high-precision gimbal control application. It is seen that the estimator works well and significantly improves performance and robustness in the presence of disturbances and uncertainties

Effects Of Bovine Lactoferrin In Surgically Created Bone Defects On Bone Regeneration Around Implants

The aim of this experimental study was to evaluate the effect of bovine lactoferrin (bLF)-loaded gelatin microspheres (GM) used in combination with anorganic bovine bone on bone regeneration in surgically created bone defects around tooth implants. Twenty-four uniform bone defects were created in the frontal bone via an extraoral approach in 12 domestic pigs. Twenty-four implants were placed at the center of the defects. In eight animals one of these defects was filled with 0.3 mL anorganic bovine bone while the other was left empty. In four animals, all defects were filled with 3 mg/defect bLF-loaded GM and anorganic bovine bone. All the defects were covered with collagen membranes. All animals were sacrificed after 10 weeks of healing, and the implants with the surrounding bone defects were removed en bloc. Undecalcified sections were prepared for histomorphometric analysis. The mean total area of hard tissue was 26.9 +/- 6.0% in the empty defect group, 31.8 +/- 8.4% in the graft group, and 47.6 +/- 5.0% in the lactoferrin group (P < 0.001). The mean area of newly formed bone was 26.9 +/- 6.0% in the empty defect group, 22.4 +/- 8.2% in the graft group, and 46.1 +/- 5.1% in the lactoferrin group (P < 0.001). The mean residual graft area was 9.4 +/- 3.2% in the graft group and 1.5 +/- 0.6% in the lactoferrin group (P < 0.001). The mean proportion of bone-implant contact in the defect region was 21.9 +/- 8.4% in the empty defect group, 26.9 +/- 10.1% in the graft group and 29.9 +/- 10.3% in the lactoferrin group (P = 0.143). These data indicate that a combination of 3 mg bLF-loaded GM and bovine-derived HA promotes bone regeneration in defects around implants.WoSScopu

Comparison of Bovine-Derived Hydroxyapatite and Autogenous Bone for Secondary Alveolar Bone Grafting in Patients With Alveolar Clefts

WOS: 000299214500016PubMed ID: 22182665Purpose: The aim of this retrospective study was to compare the long-term outcomes of secondary alveolar bone grafting (SABG) using bovine-derived hydroxyapatite versus autogenous bone. Patients and Methods: The subjects in this study were 23 patients with unilateral cleft lip and palate (13 male, 10 female) who underwent SABG from 2004 through 2009. The patients were recalled and examined to evaluate the success of the long-term outcomes of SABG. In group 1, there were 12 patients (7 male, 5 female) who underwent grafting with anterior iliac crest bone; in group 2, 11 patients (6 male, 5 female) underwent grafting with bovine-derived hydroxyapatite. Results: The mean ages at grafting were 13 +/- 3.76 years in group 1 and 10.82 +/- 2.6 years in group 2 (P = .134). The mean lengths of follow-up were 47.33 +/- 13.79 months in group 1 and 67.82 +/- 10.36 months in group 2 (P = .002). Pocket depth, periodontal index, and gingival index scores were similar and indicated acceptable periodontal status in the 2 groups. The results for patient satisfaction were not statistically different (P = .05). There was no statistically significant difference between the 2 groups when results of the Chelsea scale were analyzed (P = .05). The radiologic results showed an 83.4% success rate in group 1 and a 100% success rate in group 2 (P = .478). When the densitometric values for cleft sites were analyzed, the difference between the 2 groups was not statistically significant (P = .190). Conclusions: Bovine-derived hydroxyapatite is as successful as the iliac graft for the SABG procedure. (C) 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70: e95-e102, 201

Histomorphometric Evaluation of the Effects of Various Diode Lasers and Force Levels on Orthodontic Mini Screw Stability

Objective: The purpose of this study was to evaluate the effects of different laser dose and force levels on the stability of orthodontic mini screws used for anchorage, by histomorphometric analyses. Background data: Low-level laser therapy speeds up blood flow, improves the mechanism of the revitalization processes, reduces the risk of infection, boosts metabolic activities, and accelerates the healing of the damaged tissue. Although there are many research studies about low-level laser therapy applications in a variety of areas, no investigations were found concerning mini screw stability using various laser dose levels with different force level applications. Methods: Seventeen New Zealand white rabbits were used. A total of 68 cylindrical, self-drilling orthodontic mini screws were threaded at the fibula. Experimental subjects were divided into six groups; force application was not performed in the first three groups, whereas 150g of force was applied via nickel-titanium closed-coil springs placed between two mini screws in the other three groups. Measurements of the initial torque values (10 Ncm) were manipulated by a digital portable torque gauge. Various low-level laser doses were applied to the groups during the postoperative 10 days. After 4 weeks, bone-to-implant contact and cortical bone thickness were histomorphometrically analyzed. Results: In the 150g force plus 20 J/cm(2) dosage group, the highest bone-to-implant contact values were observed. (p<0.05) There were no statistically significant correlations between cortical bone thickness and bone-to-implant contact values; on the other hand, no significant difference was found among the same groups in terms of cortical bone thickness values (p>0.05). Conclusions: Low-level laser therapy was noticed to induce the mini screw-bone contact area. Low-level laser therapy may be a supplementary treatment method to increase the stability of the orthodontic mini screw