41 research outputs found
Моделирование магнетронной распылительной системы методом конечных элементов
В работе проведено моделирование магнетронной распылительной системы методом конечных элементов и методом Галеркина. Получены распределения концентрации и скоростей носителей заряда, распределение электрического потенциала и магнитного поля, рассмотрены временные зависимости физических величин. Разработано программное обеспечение для моделирования сложных физических задач. Проведена верификация расчетного алгоритма на примере решения модельных задач. Отличительной особенностью исследуемой модели от существующих является учет нестационарного и конвективного слагаемых в уравнении для переноса скорости электрона и максимально точная реализация всех слагаемых в дифференциальном уравнении (в рамках метода Галеркина).The dissertation examines the modeling of a magnetron sputtering system by finite element analysis and Galerkin method. The model makes it possible to calculate the concentration, velocity, temperature, electrical potential and magnetic field. The methods and the code developed according to the model are usable for modeling complex physical tasks. The work also includes analysis and verification of results
The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2
Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age 6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score 652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701
Indications to the use of condylar repositioning devices in the surgical treatment of dental-skeletal class III
Purpose: The aim of this report was to compare the clinical and radiographic findings observed at the 12-month follow-up in 2 groups of 15 patients who underwent Le Fort I and bilateral sagittal split osteotomy for the correction of dental-skeletal Class III. In the first group, the condylar positioning devices were used, whereas in the second group, an alternative method was used for the intraoperative assessment of mandibular repositioning. Materials and Methods: All of the patients of our study in the immediate presurgical period were without temporomandibular joint disorders and with a normal anatomic relationship between condyle and fossae. The condyle position and morphology were examined at the 12-month follow-up through cephalometric measurements and the postsurgical findings in both groups were compared with those observed in the presurgical period. Results: In all of the 30 patients in our study, no relapse or postsurgical temporomandibular joint disturbance was observed at the 12-month follow-up. Variations in condyle position of more than 2 mm or 2degrees were not observed in the 15 patients treated with condylar positioning devices. Changes in condyle position between 2 and 4 mm and 2degrees and 4degrees were observed in 6 of the 15 patients treated without the devices. Conclusions: The use of condylar positioning devices can be avoided in patients with dental-skeletal Class III without presurgical temporomandibular dysfunction. The manual positioning of the mandibular condyle is easier, but it requires the utmost care and an experienced operator. (C) 2003 American Association of Oral and Maxillofacial Surgeons
Warthin's tumor of the hard palate
Warthin's Tumor (WT) or papillary cystadenoma lymphomatosum is typically located in parotid gland. Extraparotid localization of WTs (EPWT) was rarely described in ectopic salivary tissue in the latero-cervical and para-parotid lymph nodes. Localization in the hard palate is exceptional. This paper describes pre-surgical diagnostic work up and surgical management of a solitary WT localized in the hard palate as found in a 27-year-old Caucasian woman. With consideration of uncertain pre-surgical diagnosis obtained with FNAC, intraoperative histologic examination of frozen sections was planned. Conservative surgical approach was performed. After WT was diagnosed with histology, a local bone curettage was made. Clinical and radiographic follow-up at 12th month was negative for relapse
Craniofacial traumas: Immediate and delayed treatment
In 1998, 28 patients with craniofacial fractures have been under observation at the Emergency Room of the Policlinico Umberto I of Rome. Twenty-six patients have undergone reduction and contention surgery of the fractures. The diagnosis of the fractures has been achieved through CT axial scanning and coronal reconstruction as well as with three-dimensional CT. The CT spiral was used in those cases that required more rapid intervention, whereas the MRI was used to evaluate the condition of the eyeball. Twenty of such patients underwent surgical treatment a few hours after the trauma and, in such cases, excellent aesthetic and functional results were achieved. The general and neurological conditions of six patients did not permit prematurely proceeding with surgery. Two patients died a few hours after the trauma of the injuries sustained. Of the six patients who underwent delayed treatment, acceptable functional and aesthetic results were achieved in four, whereas the remaining two patients had inadequate results. The results we have obtained show that it is possible to achieve the best results, both aesthetic and functional, through immediate treatment. Delayed treatment is carried out at least 2 weeks after the trauma because of the patient's condition and presents reconstruction difficulties that do not guarantee a satisfactory aesthetic reconstruction as well as, in some cases, an effective functional restoration
Differential diagnosis between adenoid cystic carcinoma and pleomorphic adenoma of the minor salivary glands of palate.
Tumors arising from minor salivary glands of the palate may exhibit an overlap of clinical and biologic features that may produce diagnostic and therapeutic dilemmas. Surgical treatment can be very different, depending on the dimensions and malignant or benign nature of the tumors, and therefore should be planned on the basis of an accurate differential diagnosis. A retrospective analysis in 24 patients with pleomorphic adenoma and adenoid cystic carcinoma of minor salivary glands of the palate was performed to investigate the accuracy of fine needle aspiration cytology (FNAC) and biopsy with histology in the preoperative diagnosis. Preoperative diagnoses obtained with FNAC and biopsy were compared with findings of the definitive histopathologic examination performed on the resected mass. Correspondence between the preoperative diagnoses determined by FNACs and the definitive histopathologic results was observed in 22 of 24 cases, whereas a complete equivalence was found with regards to histology. In the analysis, FNAC was associated with 91.6% accuracy and an error rate of 8.4% in the diagnosis of pleomorphic adenoma and adenoid cystic carcinoma of the palate. From the results of the analysis, histologic examination is still the most accurate diagnostic tool in such tumors. FNAC can be considered in tumors of the head and neck regions that are difficult to reach by means of a common biopsy
Intracellular and extracellular tumor pH measurement in a series of patients with oral cancer
Reversed pH gradient is an intrinsic feature of tumor phenotype resulting from an upregulation of glycolysis. This is crucial for tumor cell proliferation, invasion, metastasis, drug resistance, and apoptosis. Comprehension of mechanisms of pH regulation in tumors is of paramount importance for therapeutic implications. This is a preliminary report of a larger prospective study dedicated to the measurements of neutral or slightly alkaline pH/extracellular pH (pHi/pHe) in human patients affected by tumors of the head and neck. During surgery, four specimens were obtained from six patients with cancer: two from the tumor site and two from contralateral areas or sane areas near the tumor. pHe and pHi were measured and compared within normal and neoplastic tissues. Our data indicate that human spontaneous tumors show similar reversed gradients as observed in previous analysis on animal tumor models and cell lines