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Background/purpose: In orthodontic applications, NiTi wires are under continuous bending stress and exposed to fluctuations in temperature over long durations. The sensitivity of NiTi to temperature can have a considerable influence on its mechanical properties. This study investigated the effects of deflected NiTi wire, presented in stress-induced (detwinned) martensite microstructure, combined with thermal cycle on the microstructure and mechanical properties. Materials and methods: We tested four types of as-received orthodontic NiTi: (1) Nitinol Classic (3 M Unitek), (2) Sentalloy (Tomy), (3) 27 °C CuNiTi (Ormco) and (4) 40 °C CuNiTi (Ormco). Each group of specimens was subjected to three different testing conditions: (1) temperature fluctuations (5000 cycles) between 5 and 55 °C, (2) continuous three-point bending force and (3) combination of thermal cycling and bending stress. Results: The specimens that underwent thermocycling as well as loading exhibited a substantial narrowing in stress hysteresis, which may be attributed to crystallinity lower than that of as-received NiTi wires. Reduced crystallinity can manifest in a number of imperfections, such as dislocations and internal stress, as well as a less-organized structure. Micro X-ray diffraction (XRD) analysis revealed the existence of martensite phase in Sentalloy wires subject to thermal and stress conditions. Under loading conditions, stress-induced martensite of NiTi wires exposed to temperature fluctuations of 5–55 °C also induced cyclic changes in bending stress. In a simulated intra-oral environment, the stability of austenite↔martensite transformation decreased. Conclusion: This study determined that bending stress in conjunction with repeated temperature fluctuations can greatly affect the microstructure and mechanical properties of NiTi wires.

Objective: Pregnancy and menopause are significant life events associated with major changes in female hormone levels and changes in cardiovascular health. The role of estrogen in influencing cardiovascular risk is an ongoing research topic. Many studies have provided evidence that radial pressure wave characteristics are an important indicator to consistently and independently predict cardiovascular events. The aim of this study was to investigate if radial pressure wave analysis provided statistical insights into the physiological variations due to pregnancy and menopause. Furthermore, the study investigated how these variations could serve as an indicator for cardiovascular risks. As the radial pulse measurement is non-invasive and speedy, it may be helpful in evaluating cardiovascular changes and risk during these transitions. Materials and method: A total of 702 randomly selected female subjects (90 pregnant and 97 post-menopausal), aged 20–59, enrolled in the study. The visit measured the subject's hemodynamic parameters including heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP) and radial pressure waves. SBP and DBP were evaluated by an automatic blood pressure monitor. Radial pressure wave data were continuously recorded for 12-s using a TD01C pulse measuring instrument. Spectrum analysis of the radial pressure wave was performed to evaluate the first five harmonic components (C1–C5). Results: A comparison of pregnant women to non-pregnant women showed C3 and C5 were lower. Heart rate C2 and C4 were higher in pregnant women. A comparison of women pre-menopausal and post-menopausal showed no significant difference in SBP or DBP. Menopause significantly changed the C1 and C4 radial pressure wave harmonics. An increase in C1 and a decrease in C4 were observed. Conclusion and discussion: This study provided further clinical evidence to support the hemodynamic model that describes the cardiovascular changes and risks related to the harmonic components of the pulse spectrum. Beyond blood pressure, the effects of menopause on the radial pressure wave, especially on hemodynamic index C4, independent of age and BMI, may explain increased post-menopausal cardiovascular risk. This and past studies collectively suggest that radial pressure wave components may be an indicator of a female body's ability to supply oxygen and nutrients. Harmonic analysis of the radial pressure wave may provide additional insights into the underlying mechanism of the cardiovascular changes over the lifespan of a woman.

Background/purpose: The palate has become a popular site for the placement of temporary anchorage devices (TADs) owing to its bone quantity and quality. This study aimed to investigate total and cortical bone thicknesses in the whole palate as well as palatal width using a standard grid system and cone-bean computed tomography (CBCT) images. Materials and methods: The CBCT images of 43 samples were selected. The total bone and cortical bone thicknesses of the palate were surveyed on 64 points per patient. The palatal width was measured. The difference between the age and sex groups was analyzed. Results: The total palatal bone thickness in the adult group ranged from 9.85 ± 2.04 to 1.87 ± 0.79 mm. In the adolescent group, we found one-third of the incisor roots in the area 3 mm distal to the incisive foramen and 8 mm lateral to the mid-palatal suture. The cortical bone thickness in adults was significantly thicker in the posterior paramedian area than that in adolescents. Conclusion: The thickest vertical bone is located in the zone 3 mm distal to the incisive foramen and 4–8 mm lateral to the midpalate. The zone 6 mm posterior to the incisive foramen and 2–8 mm lateral to the midpalate exhibited optimal thickness and was away from the incisor roots. This region could be a safe zone for adolescent patients to place TADs. When TADs are to be inserted at the posterior palate, the 2-mm paramedian area should be the first region of choice.

Background Women not only have worse diabetes complications, but also have menstrual cycle, pregnancy, and menopause which can make managing diabetes more difficult. The aim of this study was to investigate if radial pressure wave analysis may non-invasively screen for women’s risk of type 2 diabetes. Methods Spectrum analysis of the radial pressure wave was performed to evaluate the first five harmonic components, C1 to C5. The study consisted of a total of 808 non-pregnant female subjects aged 20–95 over the period of 4 years, and 404 of them were diagnosed with Type 2 diabetes as the case group. Result The first five harmonic components are significantly different in a comparison of the case group and the control group. In the logistic regression analysis, T2DM was found to be associated with C1 (OR = 1.055, CI = 1.037–1.074, p < 0.001), C2 (OR = 1.051, CI = 1.019–1.085, p = 0.002), and C3 (OR = 0.972, CI = 0.950–0.994, p = 0.013). In the Receiver Operating Characteristic curve analysis, the Area Under Curve of using C3 only (70%, p Conclusion We thus concluded that pulse spectrum was a non-invasive predictor for women’s risk of T2DM.

BackgroundWomen not only have worse diabetes complications, but also have menstrual cycle, pregnancy, and menopause which can make managing diabetes more difficult. The aim of this study was to investigate if radial pressure wave analysis may non-invasively screen for women's risk of type 2 diabetes.MethodsSpectrum analysis of the radial pressure wave was performed to evaluate the first five harmonic components, C1 to C5. The study consisted of a total of 808 non-pregnant female subjects aged 20-95 over the period of 4 years, and 404 of them were diagnosed with Type 2 diabetes as the case group.ResultThe first five harmonic components are significantly different in a comparison of the case group and the control group. In the logistic regression analysis, T2DM was found to be associated with C1 (OR = 1.055, CI = 1.037-1.074, p < 0.001), C2 (OR = 1.051, CI = 1.019-1.085, p = 0.002), and C3 (OR = 0.972, CI = 0.950-0.994, p = 0.013). In the Receiver Operating Characteristic curve analysis, the Area Under Curve of using C3 only (70%, p ConclusionWe thus concluded that pulse spectrum was a non-invasive predictor for women's risk of T2DM.

Radiation-induced skin injury (RSI) is a frequent complication of radiotherapy. Severe cases affect the patient’s disease treatment and quality of life. The main purpose of this study is to examine the causative role of egg-yolk oil (EYO) in delayed radiation-induced skin injury, including impaired wound healing. Using polyvinyl pyrrolidone (PVP)-gelatin-chitosan (PGC) composite film as controlled release of egg-yolk oil (EYO) was studied in rats, which were used as a radiation-induced skin injury model. Different composition ratios were tested for their mechanical properties, moisture content, and degradation characteristics. The results showed that the PGC112 (w/w) substrate, which will hence be referred to as PGC, had the better properties. Further, the PGC was mixed with EYO (0.25% and 0.5%) to prepare the films (PGC/0.25EYO and PGC/0.5EYO, respectively). Furthermore, the mechanical and degradation properties and biocompatibility showed better results with PGC/0.5EYO. In animal studies, rats were irradiated with single-dose electron beams of 40 Gy. The animals were divided into five groups to perform wound treatment with various types of wound dressing for 30 days. Histological examination and CD68 immunochemical staining were then conducted, and observations were made. The results showed that PGC/0.5EYO has a significantly healing effects on radiodermatitis and good re-epithelialization.

A novel approach of making a biomimetic nerve conduit was established by seeding adipose-derived adult stem cells (ADSCs) on the external wall of porous poly(D, L-lactic acid) (PLA) nerve conduits. The PLA conduits were fabricated using gas foaming salt and solvent–nonsolvent phase conversion. We examined the effect of two different porous structures (GS and GL) on ADSC growth and proliferation. The GS conduits had better structural stability, permeability, and porosity, as well as better cell viability at 4, 7, and 10 days. The epineuriallike tissue was grown from ADSC-seeded conduits cultured for 7 days in vitro and then implanted into 10-mm rat sciatic nerve defects for evaluation. The regeneration capacity and functional recovery were evaluated by histological staining, electrophysiology, walking track, and functional gait analysis after 6 weeks of implantation. Experimental data indicated that the autograft and ADSC-seeded GS conduits had better functional recovery than the blank conduits and ADSC-seeded GL conduits. The area of regenerated nerve and number of myelinated axons quantified based on the histology also indicated that the autograft and AGS groups performed better than the other two groups. We suggested that ADSCs may interact with endogenous Schwann cells and release neurotrophic factors to promote peripheral nerve regeneration. The design of the conduit may be critical for producing a biohybrid nerve conduit and to provide an epineurial-like support.

Magnetic nanoparticles are used to enhance the image contrast of magnetic resonance imaging (MRI). However, the development of magnetic nanoparticles with a low dose/high image contrast and non-toxicity is currently a major challenge. In this study, cobalt-substituted hydroxyapatite nanoparticles deposited on titanium (Ti-CoHA) and cobalt-substituted hydroxyapatite nanoparticles deposited on titanium dioxide nanotubes (TNT-CoHA) were synthesized by the electrochemical deposition method. The particle sizes of Ti-CoHA and TNT-CoHA were 418.6 nm and 127.5 nm, respectively, as observed using FE-SEM. It was shown that CoHA can be obtained with a smaller particle size using a titanium dioxide nanotube (TNT) electrode plate. However, the particle size of TNT-CoHA is smaller than that of Ti-CoHA. The crystal size of the internal cobalt oxide of CoHA was calculated by using an XRD pattern. The results indicate that the crystal size of cobalt oxide in TNT-CoHA is larger than that of the cobalt oxide in Ti-CoHA. The larger crystal size of the cobalt oxide in TNT-CoHA makes the saturation magnetization (Ms) of TNT-CoHA 12.6 times higher than that of Ti-CoHA. The contrast in MRIs is related to the magnetic properties of the particles. Therefore, TNT-CoHA has good image contrast at low concentrations in T2 images. The relaxivity coefficient of the CoHA was higher for TNT-CoHA (340.3 mM−1s−1) than Ti-CoHA (211.7 mM−1s−1), and both were higher than the commercial iron nanoparticles (103.0 mM−1s−1). We showed that the TNT substrate caused an increase in the size of the cobalt oxide crystal of TNT-CoHA, thus effectively improving the magnetic field strength and MRI image recognition. It was also shown that the relaxivity coefficient rose with the Ms. Evaluation of biocompatibility of CoHA using human osteosarcoma cells (MG63) indicated no toxic effects. On the other hand, CoHA had an excellent antibacterial effect, as shown by E. coli evaluation, and the effect of TNT-CoHA powder was higher than that of Ti-CoHA powder. In summary, TNT-CoHA deposited electrochemically on the TNT substrates can be considered as a potential candidate for the application as an MRI contrast agent. This paper is a comparative study of how different electrode plates affect the magnetic and MRI image contrast of cobalt-substituted hydroxyapatite (CoHA) nanomaterials.

Novel nanocomposites based on type I collagen (Col) containing a small amount (17.4, 43.5, and 174 ppm) of gold nanoparticles (AuNPs, approximately 5 nm) were prepared in this study. The pure Col and Col-AuNP composites (Col-Au) were characterized by the UV-Vis spectroscopy (UV-Vis), surface-enhanced raman spectroscopy (SERS) and atomic force microscopy (AFM). The interaction between Col and AuNPs was confirmed by infrared (IR) spectra. The effect of AuNPs on the biocompatibility of Col, evaluated by the proliferation and reactive oxygen species (ROS) production of mesenchymal stem cells (MSCs) as well as the activation of monocytes and platelets, was investigated. Results showed that Col-Au had better biocompatibility than Col. Upon stimulation by vascular endothelial growth factor (VEGF) and stromal derived factor-1α (SDF-1α), MSCs expressed the highest levels of αvβ3 integrin/CXCR4, focal adhesion kinase (FAK), matrix metalloproteinase-2 (MMP-2), and Akt/endothelial nitric oxide synthase (eNOS) proteins when grown on the Col-Au (43.5 ppm) nanocomposite. Taken together, Col-Au nanocomposites may promote the proliferation and migration of MSCs and stimulate the endothelial cell differentiation. These results suggest that Col-Au may be used to construct tissue engineering scaffolds for vascular regeneration.