Оценка амплитуд и вероятностей многоэлектронных переходов в атомах на основе многочастичной теории возмущений

Излагается подход к получению приближенных формул для оценки амплитуд и вероятностей многоэлектронных переходов в атомах. Приближенные формулы получены на основе точных, в рамках определенного порядка теории возмущений, выражений и физически обосновываются. Подход позволяет не только сравнительно просто оценивать вероятности переходов и сечения процессов, но и открывает возможность выявлять доминирующие физические механизмы переходов. Рассматриваются приближения встряски, резонанса в непрерывном спектре, резонанса в дискретном спектре, неортогональных орбиталей

Loss reduсing in pulse tranformer of betatron injection system

Present betatrons have limited operating frequency, which is no more than 400 Hz. It's caused by thermal operating mode of betatron elements. High voltage injection system is the one of betatron elements. The highest thermal losses is observed in core of impulse transformer. Too high thermal losses in pulse transformer core causes distortion of high voltage injection pulse shape and break the electron capture condition. That's why the betatron dose rate is decreased

Cerebral vein thrombosis: clinical manifestation and diagnosis

BACKGROUND: Cerebral venous thrombosis (CVT) is a disease with a wide spectrum of symptoms and severity. In this study we analysed the predictive value of clinical signs and symptoms and the contribution of D-dimer measurements for diagnosis. METHODS: We evaluated consecutive patients admitted with suspected CVT receiving non-invasive imaging. Symptoms and symptom combination as well as D-dimer levels were evaluated regarding their diagnostic value. RESULTS: 239 patients were included in this study, 170 (71%) were females. In 39 patients (16%) a CVT was found. For identifying a CVT patients underwent either a venous CT-angiography or MR-angiography or both. No combination of symptoms either alone or together with the D-dimer measurements had a sensitivity and positive predictive value as well as negative predictive value and specificity high enough to serve as red flag. D-dimer testing produced rates of 9% false positive and of 24% false negative results. For D-dimer values a Receiver Operating Characteristic curve (ROC) and the area under the curve (AUC = 0.921; CI: 0.864 - 0.977) were calculated. An increase of sensitivity above 0.9 results in a relevant decrease in specificity; a sensitivity of 0.9 matches a specificity value of 0.9. This corresponds to a D-dimer cut-off level of 0.16 μg/ml. CONCLUSION: Imaging as performed by venous CT-angiography or MR-angiography has a 1 to 2 in 10 chance to detect CVT when typical symptoms are present. D-dimer measurements are of limited clinical value because of false positive and negative results

Evaluation of Medication-Related Osteonecrosis of the Jaw (MRONJ) in Terms of Staging and Treatment Strategies by Dental Students at Different Educational Levels

Background: The role of medication-related osteonecrosis of the jaw (MRONJ) as a dentomaxillo- facial pathology is becoming increasingly important due to its growing prevalence. The success of preventive and therapeutic measures relies mainly on the dentist’s ability to correctly diagnose the disease. Methods: The aim of this study was to evaluate the skills of dental students of different educational levels in choosing the correct stage, diagnostics, and treatment option for MRONJ based on clinical and radiographic imaging (panoramic radiograph, CBCT). The study was designed as a cross-sectional cohort study. Twenty dental students were asked to complete a questionnaire in their third and fifth year of studies in which they had to correctly stage the disease, choose the radiological diagnostics and recommend the treatment. The control group contained experienced oral and maxillofacial surgeons. Results: With an overall performance of 59% (third year: 145.2/248 points; fifth year: 145.3/248 points), no statistically significant difference between the educational levels could be observed. The classification based on CBCT imaging was significantly more often correct compared to panoramic radiographs (p < 0.001). Conclusions: This study highlights students’ lack of knowledge in staging, diagnostics, and treatment of MRONJ, even though the CBCT positively affected decision-making. No significant increase in knowledge could be confirmed through clinical education. This study highlights the need for students to catch up on MRONJ diagnostics and treatment planning. Further expansion of teaching in this disease’s context and X-ray diagnostics is needed

Дослідження багатошарових нейронних мереж для автоматичного виділення ознак при вирішенні задачі розпізнавання образів

В роботі розглянуто підходи до виділення ознак при розпізнаванні образів і застосування багатошарових нейронних мереж для розв'язання таких задач. Проведено процес моделювання багатошарового перцептрону для автоматичного виділення ознак зображення і подальшої класифікації. Досліджено вплив базових параметрів на якість розпізнавання.The paper deals with approaches to feature extraction in pattern recognition and application of multilayer neural nets for solving such problems. The modeling process of multilayer perceptron for automatic feature extraction and further classification is described. The basic parameters influence on quality of recognition is researched

The influence of bisphosphonates on human osteoblast migration and integrin aVb3/tenascin C gene expression in vitro

<p>Abstract</p> <p>Background</p> <p>Bisphosphonates are therapeutics of bone diseases, such as Paget's disease, multiple myeloma or osteoclastic metastases. As a severe side effect the bisphosphonate induced osteonecrosis of the jaw (BONJ) often requires surgical treatment and is accompanied with a disturbed wound healing.</p> <p>Therefore, the influence on adhesion and migration of human osteoblasts (hOB) after bisphosphonate therapy has been investigated by morphologic as well as gene expression methods.</p> <p>Methods</p> <p>By a scratch wound experiment, which measures the reduction of defined cell layer gap, the morphology and migration ability of hOB was evaluated. A test group of hOB, which was stimulated by zoledronate 5 × 10^-5M, and a control group of unstimulated hOB were applied. Furthermore the gene expression of integrin aVb3 and tenascin C was quantified by Real-Time rtPCR at 5data points over an experimental period of 14 days. The bisphosphonates zoledronate, ibandronate and clodronate have been compared with an unstimulated hOB control.</p> <p>Results</p> <p>After initially identical migration and adhesion characteristics, zoledronate inhibited hOB migration after 50 h of stimulation. The integrinavb3 and tenascin C gene expression was effected by bisphosphonates in a cell line dependent manner with decreased, respectively inconsistent gene expression levels over time. The non-nitrogen containing bisphosphonates clodronate led to decreased gene expression levels.</p> <p>Conclusion</p> <p>Bisphosphonates seem to inhibit hOB adhesion and migration. The integrin aVb3 and tenascin C gene expression seem to be dependent on the cell line. BONJ could be enhanced by an inhibition of osteoblast adhesion and migration. The gene expression results, however, suggest a cell line dependent effect of bisphosphonates, which could explain the interindividual differences of BONJ incidences.</p

Rheological and flow birefringence studies of rod-shaped pigment nanoparticle dispersions

We study rheological and rheo-optical properties of suspensions of anisometric pigment particles in a non-polar fluid. Different rheological regimes from the dilute regime to an orientationally arrested gel state were characterized and compared with existing theoretical models. We demonstrate the intricate flow behaviour in a wide range of volume fractions. A unique combination of the optical properties of the particles results in a giant rheo-optical effect: an unprecedentedly large shear stress-induced birefringence was found in the isotropic range, exhibiting a sharp pre-transitional behaviour