35 Hz shape memory alloy actuator with bending-twisting mode.

Shape Memory Alloy (SMA) materials are widely used as an actuating source for bending actuators due to their high power density. However, due to the slow actuation speed of SMAs, there are limitations in their range of possible applications. This paper proposes a smart soft composite (SSC) actuator capable of fast bending actuation with large deformations. To increase the actuation speed of SMA actuator, multiple thin SMA wires are used to increase the heat dissipation for faster cooling. The actuation characteristics of the actuator at different frequencies are measured with different actuator lengths and results show that resonance can be used to realize large deformations up to 35 Hz. The actuation characteristics of the actuator can be modified by changing the design of the layered reinforcement structure embedded in the actuator, thus the natural frequency and length of an actuator can be optimized for a specific actuation speed. A model is used to compare with the experimental results of actuators with different layered reinforcement structure designs. Also, a bend-twist coupled motion using an anisotropic layered reinforcement structure at a speed of 10 Hz is also realized. By increasing their range of actuation characteristics, the proposed actuator extends the range of application of SMA bending actuators.

Prolonged entecavir therapy is not effective for HBeAg seroconversion in treatment-naive chronic hepatitis B patients with a partial virological response.

The aims of this study were to investigate the efficacy of prolonged entecavir (ETV) therapy in treatment-naive chronic hepatitis B (CHB) patients and to determine whether continuous ETV therapy is feasible to achieve HBeAg seroconversion, particularly in patients with partial virological response (PVR). A total of 142 treatment-naive patients with CHB were enrolled. The mean duration of treatment was 65 (range, 26 to 90) months, and 86 patients (60.6%) were HBeAg positive. PVR was defined as detectable hepatitis B virus (HBV) DNA (>116 copies/ml) at year 1. The cumulative incidence of virological response (VR) increased from 54.9% at year 1 to 98.2% at year 7. HBeAg positivity (odds ratio [OR], 4.146; P = 0.001) and initial alanine aminotransferase (ALT) (OR, 0.997; P = 0.004) were independent risk factors for PVR. Among the 64 patients with PVR, 47 patients (73.4%) achieved VR within 4 years after prolonged ETV therapy without treatment adaptation. Three patients (2.1%) experienced virological breakthrough and HBV variants with genotypic resistance. The cumulative rate of HBeAg seroconversion was significantly higher in the patients with VR than in the patients with PVR (P = 0.018). None of the PVR patients with HBV DNA at ≥5,000 copies/ml at year 1 ever experienced HBeAg seroconversion. Multivariate analysis identified VR at year 1 as the only determinant of HBeAg seroconversion (hazard ratio [HR], 3.009; P = 0.010). In conclusion, although there were patients with PVR, prolonged ETV therapy showed excellent VR, with only 2.1% emergence of viral resistance during a 7-year follow-up. However, to achieve HBeAg seroconversion, drug modification is needed for HBeAg-positive patients with PVR (especially those with HBV DNA at ≥5,000 copies/ml at year 1).

Individual prediction model for lamivudine treatment response in hepatitis B virus e antigen-positive chronic hepatitis B patients.

BACKGROUND AND AIMS: Although prolonged lamivudine (LAM) therapy is associated with the emergence of LAM-resistant mutations, it is still a commonly used therapy in many Asian countries because of its established long-term safety and low cost. The aim of our study was to assess the predictors of long-term LAM treatment response and to establish an individual prediction model (IPM) for hepatitis B virus e antigen (HBeAg) seroconversion in HBeAg-positive chronic hepatitis B (CHB) patients. METHODS: This was a multicenter analysis of 838 patients treated with LAM between January 1999 and August 2004. Of these, 748 patients were followed up for at least 24 months. RESULTS: The median age was 43.0 years (range, 19-79 years) and the mean duration of LAM monotherapy was 34.2 ± 0.7 months. In the multivariate analysis, age (odds ratio [OR] = 0.974, P < 0.001), baseline alanine aminotransferase level (OR = 1.001, P = 0.014), and baseline hepatitis B virus DNA level (OR = 0.749, P < 0.001) were independent factors for HBeAg seroconversion. Based on the predictors, an IPM was established. Patients were classified into high (> 50%), intermediate (30-50%), or low (≤ 30%) response groups based on their probability of HBeAg seroconversion according to the IPM. The cumulative HBeAg seroconversion rate at 6 years for the high, intermediate, and low response groups was 66.0%, 48.5%, and 21.8%, respectively (P < 0.001). CONCLUSIONS: An IPM was developed based on predictors of HBeAg seroconversion in HBeAg-positive CHB patients on LAM monotherapy. This model will allow screening of LAM responders prior to the commencement of antiviral treatment.

Usefulness of magnifying endoscopy for iodine-unstained lesions in a high-risk esophageal cancer population.

AIM: To investigate the usefulness of magnified observations of iodine-unstained esophageal lesions in the histological diagnosis of esophageal mucosa abnormalities, in high-risk esophageal cancer groups. METHODS: The subjects included 38 patients who had at least one of the four criteria known to be high-risk factors for esophageal cancer. Following endoscopic observation, magnified observations were performed on iodine-unstained lesions of the esophagus. The total number of lesions was 43. These lesions were classified as type A (clear papilla), type B (fused papilla), and type C (non-visible papilla) according to the findings. Tissue biopsy was then carried out. Finally the histological findings were graded in terms of histological factors, and their relationships were compared. RESULTS: Of the 43 lesions, 11 were type A, 17 were type B, and 15 were type C under magnifying endoscopy. Histological findings such as inflammatory cell infiltration and basal cell hyperplasia were significantly increased in type B and type C lesions compared with type A lesions (P < 0.05). Low-grade esophageal dysplasia was apparent in 1 (9%) of 11 type A lesions, in 3 (18%) of 17 type B lesions, and in 6 (40%) of 15 type C lesions, with the highest rate in type C. CONCLUSION: Magnified observations of the esophagus, classified by papillary aspects using magnifying endoscopy of iodine-unstained lesions in high-risk esophageal cancer groups, are considered useful in estimating dysplasia and inflammation of esophageal mucosa.

[Significance of microsatellite instability in early gastric cancer treated by endoscopic submucosal dissection].

BACKGROUND/AIMS: Microsatellite instability (MSI) is defined as a change of any length due to either insertion or deletion of repeating units, in a microsatellite within a tumor when compared to normal tissue. MSI is closely related with genetic instability, particularly in hereditary nonpolyposis colorectal cancer. MSI is found in 10-50% of all gastric cancers, suggesting that MSI may play an important role in carcinogenesis. The aim of this study was to investigate the relationship between microsatellite instability and clinicopathologic features in early gastric cancers (EGCs) treated by endoscopic submucosal dissection (ESD). METHODS: We analyzed clinicopathological features of 95 specimens of EGCs including MSI, histologic type, mucin phenotype, p53, VEGF, location of cancer, depth of invasion, incidence of synchronous and metachronous cancer, age, and gender derived from 94 patients, treated by ESD during recent 19 months were analyzed in this study. RESULTS: According to microsatellite stability, MSI was observed in 13 (13.7%) cases of 95 specimens. The incidence of MSI was increased in patients with cancer at lower part of stomach and female gender. There was no significant relation between MSI and clinicopathologic features including histologic type, mucin phenotype, p53, VEGF, and depth of invasion. CONCLUSIONS: Our results demonstrate that there is no relationship between MSI and clinicopathologic features except tumor location and gender in ECGs treated by ESD. However, further studies are needed to evaluate the significance of MSI in EGCs.