Enhanced Properties of 3-MHz Sliver-Mode Vibrators for Cardiac Probes With Alternating Current Poling for Pb(Mg1/3Nb2/3)O3-PbTiO3 Single Crystals.

We investigated the effects of alternating current poling (ACP) on the piezoelectric and dielectric properties of 3-MHz sliver mode (L13 mm × W0.10-0.25 mm × T0.48 mm) vibrators fashioned from Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 (PMN-0.30PT) single crystal (SC) plate manufactured using the continuous-feeding Bridgman (CF-BM) method for cardiac probes. The ACP SC plate (L13 mm × W24 mm × T0.48 mm) exhibited ultrahigh dielectric permittivity ( εT33/ε0 ) and piezoelectric coefficient ( d33 ) of 9690 and 2920 pC/N, respectively. After array dicing, the SC slivers with widths of 0.10, 0.15, 0.20, and 0.25 mm were obtained, and their average εT33/ε0 values decreased from the SC plate εT33/ε0 by 45% (5330), 29% (6880), 19% (7840), and 15% (8240), respectively, possibly because of heat and mechanical damage during the dicing. A combination of the ACP and a postdicing direct current poling (ACP-DCP) recovered their εT33/ε0 values to 6050, 7080, 8140, and 8540, respectively. The sliver mode electromechanical coupling factors ( k'33 ) were confirmed to exceed 93% after the ACP-DCP process, which were more than 4% higher than those of DCP-DCP SC slivers. The measured impedance spectra indicated that the SC slivers with 0.10-0.20 mm in width showed no spurious mode vibration near the fundamental k'33 mode. We conclude that the ACP-DCP SC slivers maintained more enhanced piezoelectric and dielectric properties than the DCP-DCP samples. These results will have important implications for the commercial application of ACP technology to medical imaging ultrasound probes.

A Review on Alternating Current Poling for Perovskite Relaxor-PbTiO3 Single Crystals.

With the great success on verifying its effectiveness on relaxor-PbTiO3 (PT) single crystals (SCs), alternating current poling (ACP) has been taking a center as a new domain engineering method in the last few years. Compared with the conventional direct current poling (DCP), ACP enables enhanced piezoelectric and dielectric properties. In this article, research progress in ACP and perspectives are introduced. Initially, optimized conditions of ACP for relaxor-PT SCs and unsolved issues on polycrystalline ceramics and spurious modes are reviewed. Second, the ferroelectric domain size dependence of piezoelectricity associated with ACP is discussed. We hypothesize that a tradeoff between domain and domain wall contributions exists for high piezoelectricity, suggesting an optimum 109° domain wall size, which is presumably dependent on compositions, crystallographic symmetries, and domain configurations. Finally, crystals synthesized by a solid-state crystal growth (SSCG) method are briefly introduced due to their unprecedented piezoelectricity obtained by ACP ( d33  âˆ¼ 5500 pC/N). We hope that this work helps to grasp the current status of ACP and to guide future tasks to be studied.

Quality of life and self-care in elderly patients with cardiovascular diseases: The effect of a Traditional Chinese Medicine health educational intervention.

AIMS: To explore the effects of a Traditional Chinese Medicine health educational intervention on the quality of life and self-care agency of elderly patients living with chronic cardiovascular disease. BACKGROUND: Cardiovascular disease is a leading cause of morbidity and mortality worldwide. The secondary prevention and treatment for chronic cardiovascular disease emphasize the importance of lifestyle modification. However, behavior-changing is difficult and individual choices are influenced by broader environmental factors. The lifestyle intervention for the purpose of self-care enhancing should be considered the driving force from the cultural element. METHODS: The study was conducted from April 2014 to October 2014. Ninety-eight community dwelling individuals with chronic cardiovascular disease were recruited from Shaoxing and randomized. 48 participants were in the intervention group with a 6-month Traditional Chinese Medicine health education and 50 participants were in the control group with routine care. The main measurements included health-related quality of life and self-care agency, which was assessed by the Short Form-36 Chinese version and the Exercise of Self-Care Agency Scale respectively, and were measured at the baseline and post intervention (6months after baseline). RESULTS: After 6months of intervention, the quality of life and self-care agency in the intervention group were significantly improved. CONCLUSIONS: The traditional Chinese medicine health education is an effective method for promoting quality of life and self-care agency in cardiovascular disease patients. It could be applied as adjunctive care for cardiovascular disease patients self-care supporting.

A study of sociocultural factors on depression in Chinese infertile women from Hunan Province.

OBJECTIVE: To explore the sociocultural factors influencing depression in Chinese infertile women in Hunan Province. METHODS: A cross-sectional study was carried out. A total of 211 Chinese infertile women completed demographic details, a disease-related information questionnaire, a self-rating depression scale (SDS) and a social support rating scale (SSRS). RESULTS: One hundred and seven (50.71%) of the participants were classified as depressed according to the self-rating depression scale. The average SDS index score was 50.06 ± 10.59. Using analysis of variance (ANOVA), Pearson correlation and a multivariable regression analysis, the results showed family type, feelings of discrimination, social support, feelings of shame and reproductive pressures were influential factors in depression among Chinese infertile women. CONCLUSION: Sociocultural factors influence depression levels in Chinese female infertile patients. The unique aspects of Chinese culture may have a negative mental impact on the patients, and cultural factors should be taken into consideration in the development of coping strategies for Chinese infertile women.