“
“The aim is to improve the understanding

of high-field phenomena (such as preinception currents/conduction, streamer initiation and propagation) in insulating materials in terms of the molecular properties of the substances involved. In high electric fields, ionization is Blasticidin S supplier a likely process, and in all such processes, the ionization potential is an important parameter. A fundamental question is how these processes depend on the electric field, and therefore, based on the interaction between a negative point charge and a molecular cation as modeled by density functional theory, a field-dependent model for the ionization potential is developed. In addition, the first excitation energies as a function of the electric field are calculated using time-dependent density functional theory. It is demonstrated that empirical high-field conduction models for cyclohexane and n-tridecane can be explained in terms of the difference

between the ionization potential and the first excitation energy. It is also suggested that the reduction of the ionization potential with electric fields, can help explain how fast-mode streamers propagate. (c) 2011 American Institute of Physics. [doi:10.1063/1.3562139]“
“Aim: To determine the factors for predicting malignant diagnosis and limitations in ultrasonography guided fine-needle aspiration cytology of central and lateral cervical lymph nodes in patients with primary differentiated thyroid papillary carcinoma.

Methods: Biopsies of cervical lymph nodes were performed in 120 patients, AZD9291 31 of whom had subsequent surgical

diagnoses. Factors examined were patient’s age and gender of the patients, location (central and lateral compartments), hypoechogenicity with loss of hilum, microcalcification, cystic feature, minimum and maximum diameters and index value (minimum/maximum diameter).

Results: The mean minimum diameter and index value of the lymph nodes were 9.9 +/- 4.9 mm and 0.60 +/- 0.19, respectively. Microcalcifications and cystic parts were specific findings with rates of 93.9% and 95.1%, respectively. Microcalcification, cystic feature, minimum diameter and index value were poor predictors of malignancy. DMXAA chemical structure The predictors were central location (P = 0.031) and hypoechogenicity with loss of hilum in lateral neck (P = 0.019). Central nodes led to a major problem for biopsy success due to postoperative changes and anatomic position. Nondiagnostic (30%) nodes were therefore mostly central.

Conclusion: The involvement of the central neck should be a major indication of lymph node biopsy and pathological diagnosis regardless of the imaging findings. In the lateral compartment, hypoechogenicity with loss of hilum, microcalcifications, cystic parts and an index value >= 0.