Determining the Patient-Specific Optimum Osteotomy Line for Severe Mandibular Retrognathia Patients

Purpose: The purpose of this study is to suggest a patient-specific osteotomy line to optimize the distractor position and thus to minimize the disadvantages of conventional mandibular distraction osteogenesis (MDO) protocols. In addition, this study also aims to compare the conventional MDO protocols with the new MDO protocol proposed in this study in terms of both orthodontic outcomes and mechanical effects of osteotomy level on callus stabilization by means of the finite element method. Methods: A preoperative patient-specific 3-dimensional bone model was created and segmented by using computed tomography images of an individual patient. Virtual orthodontic set-up was applied to the segmented model prior to the virtual surgery. In order to compare the proposed osteotomy line with the conventional lines used in clinical applications, virtual surgery simulations were performed and callus tissues were modelled for each scenario. The comparison of the success of each osteotomy line was carried out based on the occlusion of the teeth. Results: The osteotomy line determined using the method proposed in this study has resulted in far less malocclusion than the conventional method. Namely, any angular deviation from the optimum osteotomy line determined in this study might result in deep-bite or open-bite. On the other hand, the finite element analysis results have indicated that this deviation also negatively affects the callus stability. Conclusion: In order to achieve a better MDO treatment in terms of occlusion of the teeth and the callus stability, the location of the osteotomy line and the distractor position can be computationally determined. The results suggest that MDO protocol developed in this study might be used in clinic to achieve a better outcome from the MDO treatment. Copyright © 2018 by Mutaz B. Habal, MD

Clinical and epidemiological features of Turkish children with 2009 pandemic influenza A (H1N1) infection: Experience from multiple tertiary paediatric centres in Turkey

PubMedID: 21859378Background: In April 2009 a novel strain of human influenza A, identified as H1N1 virus, rapidly spread worldwide, and in early June 2009 the World Health Organization raised the pandemic alert level to phase 6. Herein we present the largest series of children who were hospitalized due to pandemic H1N1 infection in Turkey. Methods: We conducted a retrospective multicentre analysis of case records involving children hospitalized with influenza-like illness, in whom 2009 H1N1 influenza was diagnosed by reverse-transcriptase polymerase chain reaction assay, at 17 different tertiary hospitals. Results: A total of 821 children with 2009 pandemic H1N1 were hospitalized. The majority of admitted children (56.9%) were younger than 5 y of age. Three hundred and seventy-six children (45.8%) had 1 or more pre-existing conditions. Respiratory complications including wheezing, pneumonia, pneumothorax, pneumomediastinum, and hypoxemia were seen in 272 (33.2%) children. Ninety of the patients (11.0%) were admitted or transferred to the paediatric intensive care units (PICU) and 52 (6.3%) received mechanical ventilation. Thirty-five children (4.3%) died. The mortality rate did not differ between age groups. Of the patients who died, 25.7% were healthy before the H1N1 virus infection. However, the death rate was significantly higher in patients with malignancy, chronic neurological disease, immunosuppressive therapy, at least 1 pre-existing condition, and respiratory complications. The most common causes of mortality were pneumonia and sepsis. Conclusions: In Turkey, 2009 H1N1 infection caused high mortality and PICU admission due to severe respiratory illness and complications, especially in children with an underlying condition. © 2011 Informa Healthcare.Ankara Universitesi Medical School, University of Michigan 7Pediatric 5Pediatric Faculty of Medicine, Assiut UniversityFrom the 1Department of Pediatrics,Ankara University Medical School,Ankara,Turkey,2Department of Pediatric Infection Diseases,Dr.Sami Ulus Maternity and Children Training and Research Hospital,Ankara,Turkey, 3Department of Pediatrics, Republic of Turkey Ministry of Health Ankara Dıs¸kapı Children’s and Research Hospital, Ankara,Turkey, 4Department of Pediatrics, Ondokuz Mayıs University Medical School, Samsun,Turkey, 5Pediatric Infectious Diseases Unit,Dr.Behçet Uz Children’s Hospital,Izmir,Turkey,6Division of Pediatric Infectious Diseases,S¸is¸li Etfal Training and Research Hospital, Istanbul,Turkey, 7Pediatric Infectious Diseases Unit, Department of Pediatrics, Hacettepe University Faculty of Medicine,Ankara,Turkey,8Division of Pediatrics,Adana Numune Research and Training Hospital,Adana, Turkey,9Department of Pediatrics,Gazi University Medical School,Ankara,Turkey,10Department of Pediatrics,Selçuk University Meram Medical Faculty, Konya,Turkey, 11Department of Pediatrics and Pediatric Infectious Diseases, Uludag^ University Medical School, Bursa,Turkey, 12Clinics of Pediatrics,Tepecik Training and Research Hospital, Izmir,Turkey, 13Division of Pediatric Infectious Diseases, Department of Children’s Health and Diseases, Çukurova University Faculty of Medicine,Adana,Turkey,14Department of Pediatrics,Eskis¸ehir Osmangazi University Faculty of Medicine,Eskis¸ehir, Turkey, 15Pediatric Infectious Diseases Unit, Department of Pediatrics, Süleyman Demirel University Faculty of Medicine, Isparta,Turkey, 16Department of Pediatrics, Marmara University Medical School, Istanbul,Turkey, 17Department of Pediatrics,Mersin University Medical School,Mersin,Turkey,and 18Department of Biostatistics,Ankara University Medical School, Ankara, Turke

Formaldehyde Selectivity in Methanol Partial Oxidation on Silver: Effect of Reactive Oxygen Species, Surface Reconstruction, and Stability of Intermediates

© 2021 American Chemical Society.Selective oxidation reactions on heterogeneous silver catalysts are essential for the mass production of numerous industrial commodity chemicals. However, the nature of active oxygen species in such reactions is still debated. To shed light on the role of different oxygen species, we studied the methanol oxidation reaction on Ag(111) single-crystal model catalyst surfaces containing two dissimilar types of oxygen (electrophilic, Oe and nucleophilic, On). X-ray photoelectron spectroscopy and low energy electron diffraction experiments suggested that the atomic structure of the Ag(111) surface remained mostly unchanged after accumulating low Oe coverage at 140 K. Temperature-programmed reaction spectroscopic investigation of low coverages of Oe on Ag(111) revealed that Oe was active for methanol oxidation on Ag(111) with a high selectivity toward formaldehyde (CH2O) production. High surface oxygen coverages, on the other hand, triggered a reconstruction of the Ag(111) surface, yielding Ag oxide domains, which catalyzes methanol total oxidation to CO2 and decreases the formaldehyde selectivity. This important finding indicates a trade-off between CH2O selectivity and methanol conversion, where 93% CH2O selectivity can be achieved for an oxygen surface coverage of θO = 0.08 ML (ML = monolayer) with moderate methanol conversion, while methanol conversion could be boosted by a factor of μ4 for θO = 0.26 ML with a suppression of CH2O selectivity to 50%. Infrared reflection absorption spectroscopy results and density functional theory calculations indicated that Ag oxide contains dissimilar adsorption sites for methoxy intermediates, which are also energetically less stable than that of the unreconstructed Ag(111). The current findings provide important molecular-level insights regarding the surface structure of the oxidized Ag(111) model catalyst directly governing the competition between different reaction pathways in methanol oxidation reaction, ultimately dictating the reactant conversion and product selectivity