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Al x In y Ga (1 − x − y) N / GaN heterostructures were grown on 4-in. p -type Si wafers to investigate the effect of In composition in the quaternary nitride layer on the electrical performance of Al 2 O 3 / AlInGaN / GaN -based normally-ON metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs). From the comparative study of the electrical measurements, it was observed that the transport properties of the devices were relatively poor in the presence of higher In composition in the quaternary-N layer. The deterioration of the electrical characteristics of MIS-HEMTs originated from the formation of deep pits on the AlInGaN epilayer surface caused by the segregation of In atoms during epitaxial growth. However, the formation of such pits was reduced for the quaternary epilayer with lower In content and exhibited better transport performance. A maximum current density (I d , m a x ) of 780 mA/mm with a specific ON-resistance of 0.71 m Ω cm 2 was observed for the device fabricated on the wafer with an In composition of 9% in the AlInGaN epilayer. We have achieved a high breakdown voltage of 793 V with a device with the gate-to-drain distance (L g d ) of 20 μ m under the off-state condition. [ABSTRACT FROM AUTHOR]

Teaching pendants with multiple buttons are commonly employed to control working robots; however, such devices are not easy to operate. As an alternative, gesture-based manipulation methods using the operator's upper limb movements have been studied as a way to operate the robots intuitively. Previous studies involving these methods have generally failed to consider the changing viewpoint of the operator relative to the robot, which may adversely affect operability. This study proposes a novel evaluation method and applies it in a series of experiments to compare the influence of viewpoint change on the operability of the gesture- and button-based operation methods. Experimental results indicate that the operability of the gesture-based method is superior to that of the button-based method for all viewpoint angles, due mainly to shorter non-operating times. An investigation of trial-and-error operation indicates that viewpoint change makes positional operation with the button-based method more difficult but has a relatively minor influence on postural operation. [ABSTRACT FROM AUTHOR]

Objective: To assess the utility of a newly developed squash cytology (SC)‐based scoring system for accurate intraoperative diagnosis of schwannoma. Methods: We first compared SC‐based and frozen section (FS) diagnoses with final pathological diagnoses of schwannoma (16 cases), meningioma (39 cases) and low‐grade astrocytoma (16 cases). Then, by logistic regression modeling, we identified features of SC preparations that were independently predictive of schwannoma. To develop a diagnostic scoring system, we assigned one point to each feature, and performed receiver operating characteristic analysis to determine the score cut‐off value that was most discriminatory for differentiating schwannoma from the other tumour types. We then compared accuracy, sensitivity, and specificity of diagnosis before and after the application of the scoring system. Results: Overall diagnostic concordance rates for SC and FS were almost the same, at 73.2% (52/71) and 77.5% (55/71 cases), respectively. Of the 16 SC features entered into the analysis, the following nine were found to independently predict schwannoma, and were thus incorporated into the scoring system: smooth cluster margins, few or no isolated tumour cells, fibrillary stroma, spindle‐shaped nuclei, parallel arrangement of stroma, parallel arrangement of nuclei, presence of anisonucleosis, absence of nucleoli, and hemosiderin deposition. A cut‐off score of four items yielded the best sensitivity, specificity and predictive values for prediction of schwannoma. Use of the scoring system improved accuracy of intraoperative diagnosis from 80.3% to 94.4%, sensitivity from 56.2% to 93.8%, and specificity from 87.3% to 94.5%. Conclusion: Our proposed SC‐based scoring system will increase accuracy of intraoperative diagnosis of schwannoma vs non‐schwannoma tumours. [ABSTRACT FROM AUTHOR]

Objective: We assessed whether intraoperative squash cytology could provide surgeons with a qualitative diagnosis of brain lesions when frozen section diagnosis is equivocal. Methods: The study included 51 lesions that were diagnosed intraoperatively as equivocal brain tumour on the basis of frozen section. We retrospectively classified the lesions into five groups according to the final histopathological diagnoses (I: malignant lymphomas; II: diffuse astrocytic and oligodendroglia tumours; III: pituitary adenomas, IV: metastatic carcinomas; V: others). We assessed the squash cytology features of Groups I–IV and of the specific lesion types, and compared features among the groups. Results: The four groups differed in a range of salient cytomorphological features: lymphoglandular bodies in Group I (eight of nine cases), cytoplasmic fibrillary processes in Group II (six of eight cases), low‐grade nuclear atypia in Group III (seven of seven cases), and large nuclei (approximately 80 μm2) and nuclear crush artefacts in Group IV (seven of nine cases). Conclusion: Findings of lymphoglandular bodies on intraoperative squash cytology can be considered characteristic of malignant lymphomas, while cytoplasmic fibrillary processes indicate diffuse astrocytic and oligodendroglial tumours. We conclude that squash cytology could yield a qualitative intraoperative diagnosis in over 25% of cases for which frozen section yields a diagnosis of equivocal brain tumour. This study retrospectively assessed the value of intraoperative cytology of squash preparations in cases for which frozen section yielded an intraoperative diagnosis of "equivocal brain tumor". Based on the squash preparations, the authors were able to provide a qualitative intraoperative diagnosis in 27% of equivocal cases and in the majority of these finally diagnosed as malignant lymphoma or glioma. [ABSTRACT FROM AUTHOR]

To address the diagnostic performance of scratch‐imprint cytology (SIC), in this study we compared intraoperative diagnoses of pulmonary lesions between SIC and frozen section histology (FSH) for accuracy with respect to the final pathological diagnosis. We histologically divided 206 pulmonary lesions (resected surgically) into two groups (benign and malignant) and compared each intraoperative diagnosis by SIC and FSH with the final pathological diagnoses. We also examined the radiological existence of pure ground‐glass opacity (GGO) nodules in each group. The diagnostic sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 91.5%, 100%, 100%, 63.6%, and 92.6%, respectively for SIC, and 98.2%, 100%, 100%, 92.1% and 98.5%, respectively, for FSH. Thus, we concluded that diagnosis by SIC is reliable for malignancy, but not for benign lesions. All pure GGO nodules (19; 9.2%) were noninfectious and malignant with a high accuracy of FSH diagnosis (100%), in comparison with those of low accuracy with a SIC diagnosis (57.9%). SIC can be an appropriate intraoperative diagnostic tool where multiple cytotechnologists observe intraoperative SIC preparations scratched evenly across the whole lesion including the peripheral area of the mass. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to determine the reliability of imprint cytology (IC) for intraoperative diagnosis of pulmonary lesions. Methods: We reviewed 113 cases of pulmonary lesion resection for which a scratch imprint was made intraoperatively. We divided the specimens into two groups (benign and malignant) and compared the scratch IC‐based diagnoses against the final histopathological diagnoses in each group for concordance. We also analysed those cases in which the scratch IC preparation was classified as inadequate. Results: The sensitivity, specificity, positive and negative predictive values, and accuracy of IC diagnoses among the patient cohort were 87.7% (72/82), 100% (7/7), 100% (72/72), 41.2% (7/17) and 88.8% (79/89), respectively. IC yielded some false‐negative results in terms of malignancy, although most of these imprints were of early cancer or cancer with mild cytological atypia. Five (41.6%) of 12 lesions for which the imprint was deemed inadequate were diagnosed histologically as granulomas with caseous necrosis. Conclusion: IC‐based diagnoses of pulmonary lesions as malignant corresponded well with the final histopathological diagnoses, but IC‐based diagnoses of negative (ie, without malignant cells) were not as reliable. Thus, pathologists should recognise the limitations of IC, especially for identifying malignant lesions. Also, the possibility of latent bacterial infection in a granuloma with caseous necrosis indicates that an IC preparation deemed inadequate for diagnosis should not be ignored. Imprint cytology correlated well with the final histopathological assessment for malignant diagnoses, however, it missed infections such as TB when caseous necrosis was not recognised and the specimen was reported as negative or non‐diagnostic. This has implications for observing health and safety regulations for frozen sections even on non‐diagnostic imprints. [ABSTRACT FROM AUTHOR]