Introduction Due to indeterminate cytology, Bethesda III is the most controversial category within the Bethesda System for Reporting Thyroid Cytopathology. This study examines the characteristics and malignancy rates of thyroid nodules (TNs) classified as Bethesda III. Methods Data were collected by reviewing electronic medical records, encompassing demographic details, medical history, chief complaint, laboratory tests (including thyroid function tests), preoperative imaging, cytology results, management, and histopathology diagnosis. Results The majority of the cases were female (84.7%). Patients’ ages ranged from 15 to 71 years, with a mean of 42.9 ± 10.5 years. Regarding goiter grading, 37 cases (21.8%) were classified as G0, 62 (36.5%) as G1, 55 (32.3%) as G2, and seven (4.1%) as G3. Thyroid Imaging Reporting and Data Systems scoring categorized the nodules as TI-RADS 2 (5.3%), TI-RADS 3 (40%), TI-RADS 4 (38.2%) and TI-RADS 5 (9.4%). The size of TNs on ultrasound ranged from 0.3 cm to 7.8 cm, with a mean size of 2.06 ± 1.3 cm. Adenoma was the most common diagnosis (40%), followed by thyroiditis (16.5%), papillary thyroid carcinoma (15.9%), and papillary thyroid microcarcinoma (15.9%). The nodules were predominantly benign (64.7%), while 35.3% were malignant. Patients with malignant nodules were younger than those with benign nodules (p=0.044). Benign nodules were significantly larger than malignant ones (p-value = 0.003). Conclusion One of three TNs with indeterminate cytology may be malignant. Patients with malignant nodules tend to be younger than those with benign nodules, and benign nodules are likely larger than malignant ones.
This article presents an overview of the “Nanolith” parallel electron-beam (e-beam) lithography approach. The e-beam writing head consists of an array of microguns independently driven by an active matrix complementary metal–oxide–semiconductor circuit. At the heart of each microgun is a field-emission microcathode comprised of an extraction gate and vertical carbon nanotube emitter, whose mutual alignment is critical in order to achieve highly focused electron beams. Thus, in this work, a single-mask, self-aligned technique is developed to pattern the extraction gate, insulator, and nanotubes in the microcathode. The microcathode examined here (150×150 gates, 2 μm gate diameter, with multiple nanotubes per gate) exhibited a peak current of 10.5 μA at 48 V when operated with a duty cycle of 0.5%. The self-aligned process was extended to demonstrate the fabrication of single nanotube-based microcathodes with submicron gates.
Transverse electron focusing is reported for hot electrons. Differential transresistance measurements show anomalous behavior at high electron energies. Corresponding dc electron focusing data reveal that the differential characteristics arise from the electron energy dependences of the mean free path and specularity coefficient. The variation of mean free path with energy is derived from the experimental data.
A high-voltage (100 kV) variable-shaped electron beam lithography system has been developed. With this system it is possible to improve the edge resolution in variable-shape lithography to better than 0.1 μm even at high beam currents. In addition the other advantages of high-voltage lithography such as reduced proximity effect, improved line width control in lithography over steps in the substrate, and better profiles on thick resist overlayers are also obtained. Experimental results are compared with simulation from a Monte Carlo based model of the electron column which predicts the benefits of working at higher beam voltage than the conventional 20 kV. Results are presented which show current profiles and exposures in resist of patterns with sizes from 5 μm×5 μm to ∼1 μm×1 μm with sub 0.1 μm resolution at beam voltages of 70 kV and greater while maintaining a beam current of >3 μA.
We report on the transport characteristics of individual multiwalled carbon nanotube/nanofibers (MWCNTs) grown by plasma-enhanced chemical vapor deposition (PECVD). The measurements were performed on individual MWCNT nanobridges suspended by sputtered Nb contacts. Temperature dependent measurements of conductance revealed that the conductance is dominated by a contribution from thermally activated carriers. High-field measurements show that the PECVD grown MWCNTs are able to carry high current densities (∼108 A/cm2) and after reaching a critical limit, break down in segments of nanotube shells while still being electrically stable. The high-density current transport and reliability make PECVD grown MWCNTs good candidates for applications as field emission cathodes and nanoelectronic interconnects.