Morphotropic Phase Boundary in Polarized Organic Piezoelectric Materials.

Designing the morphotropic phase boundary (MPB) has been the most sought-after approach to achieve high piezoelectric performance of piezoelectric materials. However, MPB has not yet been found in the polarized organic piezoelectric materials. Here, we discover MPB with biphasic competition of ß and 3/1-helical phases in the polarized piezoelectric polymer alloys (PVTC-PVT) and demonstrate a mechanism to induce MPB using the compositionally tailored intermolecular interaction. Consequently, PVTC-PVT exhibits a giant quasistatic piezoelectric coefficient of >32 pC/N while maintaining a low Young's modulus of 182 MPa, with a record-high figure of merit of piezoelectricity modulus of about 176 pC/(N·GPa) among all piezoelectric materials.

Number of natural teeth, denture use and mortality in Chinese elderly: a population-based prospective cohort study.

BACKGROUND: The associations between the number of natural teeth/denture use and all-cause mortality remain unclear due to lake of investigation for the potential interaction between tooth loss and denture use and for the potential changes in these exposures over time in older adults. We undertake this study to evaluate the associations of the number of natural teeth and/or denture use with mortality in Chinese elderly. METHODS: This is a prospective cohort study of 36,283 older adults (median age: 90). The number of natural teeth and denture use were collected with structured questionnaire. We evaluated hazard ratios (HRs) and confidence intervals (CIs) using a Cox proportional hazards model adjusting for demographic factors, education, income, lifestyle factors, and comorbidities. RESULTS: We documented 25,857 deaths during 145,947 person-years of observation. Compared to those with 20+ teeth, tooth loss was associated with a gradual increase in mortality, with an adjusted HR of 1.14 (95% CI, 1.06 to 1.23) for those with 10-19 teeth, 1.23 (95% CI, 1.15 to 1.31) for those with 1-9 teeth, and 1.35 (95% CI, 1.26 to 1.44) for those without natural teeth. Denture use was associated with lower risk of mortality (adjusted HR 0.81; 95% CI, 0.77 to 0.84). Subgroup analyses indicated that the benefit of denture use was greater in men than in women (P = 0.02) and tended to decrease with age (P < 0.001). The effects of denture use did not differ among various degrees of tooth loss (P = 0.17). CONCLUSIONS: Tooth loss was associated with an increased risk of mortality in older adults. Denture use provided a protective effect against death for all degrees of tooth loss however, this effect appeared to be modified by sex and age.

Bioinspired Wear-Resistant and Ultradurable Functional Gradient Coatings.

For mechanically protective coatings, the coating material usually requires sufficient stiffness and strength to resist external forces and meanwhile matched mechanical properties with the underneath substrate to maintain the structural integrity. These requirements generate a conflict that limits the coatings from achieving simultaneous surface properties (e.g., high wear-resistance) and coating/substrate interfacial durability. Herein this conflict is circumvented by developing a new manufacturing technique for functional gradient coatings (FGCs) with the material composition and mechanical properties gradually varying crossing the coating thickness. The FGC is realized by controlling the spatial distribution of magnetic-responsive nanoreinforcements inside a polymer matrix through a magnetic actuation process. By concentrating the reinforcements with hybrid sizes at the surface region and continuously diminishing toward the coating/substrate interface, the FGC is demonstrated to exhibit simultaneously high surface hardness, stiffness, and wear-resistance, as well as superb interfacial durability that outperforms the homogeneous counterparts over an order of magnitude. The concept of FGC represents a mechanically optimized strategy in achieving maximal performances with minimal use and site-specific distribution of the reinforcements, in accordance with the design principles of many load-bearing biological materials. The presented manufacturing technique for gradient nanocomposites can be extended to develop various bioinspired heterogeneous materials with desired mechanical performances.

lncRNA H19 facilitates the proliferation and differentiation of human dental pulp stem cells via EZH2-dependent LATS1 methylation.

Human dental pulp stem cells (hDPSCs) have been recognized as a candidate cell source for tissue engineering. Long non-coding RNAs (lncRNAs) are differentially expressed in inflamed human dental pulp tissues. The present study is aimed at investigating the role of lncRNA H19 in the differentiation potential of hDPSCs. hDPSCs were successfully isolated and cultured, followed by conducting gain and loss-of-function experiments on lncRNA H19 and large tumor suppressor 1 (LATS1) to elucidate their respective biological functions in hDPSCs. lncRNA H19 was able to promote, whereas LATS1 was found to inhibit the differentiation, proliferation, and migration capabilities of hDPSCs. LATS1 was found to activate the Hippo-Yes-associated protein (YAP) signaling pathway by decreasing levels of YAP and Tafazzin (TAZ). The effects of lncRNA H19 on hDPSCs were achieved by repressing LATS1 through enhancer of zeste homolog 2-induced trimethylation of histone 3 at lysine 27. Finally, hDPSCs overexpressing lncRNA H19 and/or LATS1 were transplanted into nude mice. It was shown that lncRNA H19 inhibited LATS1 to promote the production of odontoblasts in vivo. Taken together, lncRNA H19 serves as a contributor to the differentiation potential of hDPSCs via the inhibition of LATS1, therefore highlighting novel therapeutic targets for dental pulp repair.

[Construction of tissue engineered gingiva with gingival epithelia and acellular dermal matrix].

OBJECTIVE: To culture human gingival epithelia in vitro, and to construct the tissue engineered gingiva with the acellular dermal matrix (ADM). METHODS: Human gingival epithelia were isolated from the gingival tissue, and the cells were cultured and seeded onto the surface of ADM. After 7 days of submerged incubation, an air-liquid interface culture was performed for 7, 14, and 21 days. The complex constructed above was taken for histological examination. RESULTS: Human gingival epithelia could proliferate well on the surface of ADM, and form multilayer structure. But the superficial epithelium was partially keratinized. CONCLUSION: Tissue engineered gingiva may be constructed with human gingival epithelia and ADM in vitro.

In-situ preparation of scholzite conversion coatings on titanium and Ti-6Al-4V for biomedical applications.

A scholzite (CaZn2(PO4)2·2H2O) coating was prepared in situ on commercially pure titanium (cpTi) and Ti-6Al-4V (Ti64) substrates using the chemical conversion technology, and its phase composition and microstructure, as well as mechanical, chemical and biological properties were investigated to explore potential applications as a bioactive coating on bone implants. It is indicated that the coating consists mainly of monoclinic scholzite crystals with nano-thick laminar morphology. The crystals on cpTi aggregate to flower-like particles with the diameter of 5-10µm, while form a network structure homogeneously on Ti64. The scratch test shows that the interfacial bonding strength between the coatings and substrates is higher than 40N. Electrochemical measurements indicate that the corrosion behavior of the coatings is not inferior compared with that of oxide film on substrates. MG63 osteoblast-like cells show good adherence and significantly proliferation and differentiation characteristics on the scholzite coated cpTi and Ti64 (p<0.05) in in-vitro cell tests, demonstrating the cytocompatibility of Ti is significantly improved by the scholzite coating. It is suggested that the scholzite coating might be a promising option in hard tissue replacements for early osteogenesis.

[A cross-sectional survey on human immunodeficiency virus infection in a former commercial blood donating community, Shanxi Province].

OBJECTIVE: To determine the sero-prevalence of and the risk factors for human immunodeficiency virus infection among residents in a former commercial blood donating community, Shanxi Province. METHODS: A community-based cross-sectional survey was conducted among all residents aged 18 - 64 years in 4 villages in a rural county of Shanxi Province. A standardized structured questionnaire was administered to collect socio-demographic, medical and risk behavioral information. Venous blood was collected for HIV antibody testing. Generalized estimating equation with logistic regression was used to analyze the risk factors for HIV infection. Population attributable fraction was used to evaluate the role of public health in the risk factors for the incidence of HIV. RESULTS: A total of 3062 villagers participated in the study and provided their blood samples for HIV antibody testing. 29.5% of the participants had a history of selling blood and/or plasma. Among the subgroup of former blood donors (FBDs), 71.9% sold whole blood only, 4.1% sold plasma only and 24.0% sold both. Forty HIV infected persons were identified in the four villages. HIV prevalence was 1.3%, overall, 4.1% in FBDs and 0.1% in non-FBDs in the community. Amongst the subgroup of FBDs, HIV prevalence was 1.5% for whole blood only, 21.6% for plasma only and 8.8% for both. Univariate analysis showed that village of residence, education, marital status, gender, plasma/blood donation were statistically associated with HIV seropositivity in the villagers. Other variables, such as gender, age, occupation, number of sexual partners, drug use, histories of tooth extraction, acupuncture, surgical operation and medical injection were not found to be statistically associated with HIV seropositivity. Multivariate analysis found that selling whole blood only (adjusted OR = 13.25, 95% CI: 3.02 - 58.25) and selling plasma or both (adjusted OR = 87.85, 95% CI: 22.22 - 347.27) were significantly associated with HIV seropositivity, and the additive population attributable fraction (PAF) was 89.8%. Villagers in village 03 were more likely to be HIV positive than those in village 04 (adjusted OR = 12.26, 95% CI: 1.46 - 103.00). CONCLUSION: At present, HIV epidemic in the former commercial blood donating community has a low prevalence in Shanxi Province and the majority of HIV infections should be related to the blood and plasma donation. This study reveals the existence of HIV second-generation transmission from the infected blood donors to the general population. However, HIV had not been evidently extended from the blood/plasma donors to general population.

A cross-sectional study of health-related behaviors in rural eastern China.

OBJECTIVE: This study examined the status of health-related behaviors among rural residents and the factors influencing the practice of such behaviors. METHODS: One thousand and ninety subjects aged 15 years or over in a rural community, Anhui Province, China were surveyed. A questionnaire was used to collect information on the health knowledge, attitude and behavior of the subjects. Information on health behavior included smoking, drinking, dietary habits, regular exercises, sleeping pattern and oral health behavior. RESULTS: The prevalence of smoking and drinking in the male subjects was 46.5% and 46.9%, respectively. There was a positive significant association between smoking and drinking. Only 8.3% of all subjects ate three regular meals a day regularly. Among subjects who ate two meals a day, 89.7% did not have breakfast. Only 1.7% of subjects took part in regular exercise. About 85% of subjects slept 6 to 8 h per day. Only 38.4% of the respondents had the habit of hand washing before eating and after using the lavatory. 79.3% of the subjects brushed their teeth every day, and among them, only 10.6 percent brushed their teeth twice a day. Further analyses showed that 64.8% of subjects had 3-5 items of positive health behaviors out of 8 items and only 16.9% had six or more items. Logistical regression analyses suggested that better health behavior was affected by sex, age, years of education, income and health knowledge. CONCLUSION: The status of health behaviors among rural residents was generally poor. It is thus urgent to reinforce health education in rural communities in China.