The most important parameter characterizing a piezoelectric material is the electromechanical coupling coefficient, which specifies the conversion efficiency between electrical and mechanical energies for a given vibration mode. For the resonance along the poling direction, there are two coupling coefficients defined, i.e., kt and k33, which are for resonators of the same mode but two extreme aspect ratios and they differ substantially. We have derived a unified formula for this coupling coefficient as a function of the vibrator aspect ratio. The unified formula can provide more accurate description to the effective coupling coefficient of resonators not satisfying the extreme aspect ratio requirements.

Background: It is difficult to distinguish parathyroid lesions (PLs) from thyroid lesions using fine needle aspiration cytology (FNAC) because of their proximity and their similar cytomorphological features. Methods: FNAC smears of 46 patients with pathologically proven PLs that were histologically diagnosed as parathyroid adenoma (PA, n = 35), parathyroid hyperplasia (PH, n = 3), atypical parathyroid adenoma (APA, n = 1), and parathyroid carcinoma (PC, n = 7) were retrospectively reviewed and analyzed. Results: Our initial cytological diagnoses indicated correct diagnoses in 31 of 46 PL patients (67%). The 15 erroneous diagnoses were 5 patients with non-specific benign disease (11%), 4 with nodular hyperplasia of the thyroid (9%), 5 with atypical cells (11%), and 1 with a metastatic papillary thyroid carcinoma (2%). Follicular pattern, papillary structures, colloid-like material, and macrophages, which often suggest thyroid lesions, were also present in some PLs. We found that branching capillaries along the papillary structures, stippled nuclear chromatin, and frequent occurrence of naked nuclei were useful for determining a parathyroid origin. Conclusions: It is important to be aware that PLs are frequently mistaken for thyroid lesions based on FNAC. The specific and unique characteristics of PLs identified here may be helpful in diagnosis.

연구의 필요성노화에Purpose: This study was done to investigate the motivational, physical and affective benefits of exergaming in community dwelling older adult women. Methods: The research design was a nonequivalent control group pre-test and post-test design. Sixty-one older adult women over the age of 65 were recruited from 6 community senior centers to participate in the 8 week exercise intervention or control group. Six centers were divided into one of three groups: exergame, qigong exercise, or control. The exergame and the qigong exercise group received 16 sessions, scheduled twice a week, with each session lasting 50 minutes. Test measures were completed before and after the 8 week intervention period for all participants. Measures included: Grip strength, chair stand, 6 m walking, balance, geriatric depression scale, vitality and intrinsic motivation. Results: There were significant improvements in the exergame and qigong exercise group for grip strength, chair stand, 6m walking, balance, vitality and intrinsic motivation at the end the 8-week program compared with the control group. Conclusion: The exergame could be an effective alternative for older adult women to group exercise classes. If the original work is properly cited and retained without any modification or reproduction, it can be used and re-distributed in any format and medium.

These results were lower than those of other domestic studies. This is the first well-designed total-population based epidemiologic study on the prevalence rate of dementia of the aged residing in Busan city. Further studies for evaluating the relationships with type and severity of dementia are needed.

One of the most important parameters for characterizing piezoelectric materials is the so-called electromechanical coupling coefficient, k, which describes the electromechanical coupling strength. Although this parameter should be an intrinsic material parameter, it appears to depend on the aspect ratio of the resonator. There are three different values defined for three extreme geometries, k 33 , k 33 Ј , and k t , and they differ by more than 50%. Unfortunately, these three values cannot describe resonators of general geometries and also create conceptual confusion. Here, we provide a unified formula that will accurately describe the coupling coefficient of rectangular slender bar transducer array element with any aspect ratio.

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BackgroundIt is difficult to correctly diagnose follicular neoplasms (FNs) on fine-needle aspiration cytology (FNAC) because it shares many cytological features with other mimicking lesions. The aim of this study was to identify the cytological features that differentiate FNs from mimicking lesions. MethodsWe included the cytological slides from 116 cases of thyroid FN diagnosed on FNAC, and included their subsequent histological diagnoses. We evaluated the cytological architectural pattern and nuclear features of the lesions according to their histological groups. ResultsThe final histological diagnoses of the 116 cases varied, and included 51 FNs (44%), 47 papillary thyroid carcinomas (40%) including follicular variant, and seventeen cellular nodular hyperplasias (15%). Regardless of the final histological diagnosis, microfollicular pattern was observed in most cases. On the other hand, trabecular pattern was identified in 34% of FNs, but not in any other lesions. Additionally, elongated nuclei and ground glass chromatin were found in only some papillary thyroid carcinomas. ConclusionsThis study shows that the trabecular pattern is a representative cytological feature of FNs that can be used to distinguish FNs from mimicking lesions. In addition, nuclear shape and chromatin pattern can be used to further confirm the diagnosis of FNs from mimicking lesions through FNAC.