Sensorless control for a sophisticated artificial myocardial contraction by using shape memory alloy fibre

The authors have been developing an artificial myocardium, which is capable of supporting natural contractile function from the outside of the ventricle. The system was originally designed by using sophisticated covalent shape memory alloy fibres, and the surface did not implicate blood compatibility. The purpose of our study on the development of artificial myocardium was to achieve the assistance of myocardial functional reproduction by the integrative small mechanical elements without sensors, so that the effective circulatory support could be accomplished. In this study, the authors fabricated the prototype artificial myocardial assist unit composed of the sophisticated shape memory alloy fibre (Biometal), the diameter of which was 100 microns, and examined the mechanical response by using pulse width modulation (PWM) control method in each unit. Prior to the evaluation of dynamic characteristics, the relationship between strain and electric resistance and also the initial response of each unit were obtained. The component for the PWM control was designed in order to regulate the myocardial contractile function, which consisted of an originally-designed RISC microcomputer with the input of displacement, and its output signal was controlled by pulse wave modulation method. As a result, the optimal PWM parameters were confirmed and the fibrous displacement was successfully regulated under the different heat transfer conditions simulating internal body temperature as well as bias tensile loading. Then it was indicated that this control theory might be applied for more sophisticated ventricular passive or active restraint by the artificial myocardium on physiological demand.

Long-term follow-up results of endoscopy-assisted breast surgery (EBS) for early breast cancer

Abstract #4145

Introduction: Although endoscopy-assisted breast surgery(EBS) for early breast cancer had shown the excellent cosmetic outcomes, the application of ESSB is still controversial because of the scanty evidence of long-term safety and feasibility. This study is to evaluate the long-term outcome of endoscopy-assdisted breast surgery compared to conventional breast surgery for early breast cancer.
 Patients and Methods: Between January 2002 through December 2006, 76 patients(Group E) who had diagnosed breast cancer underwent EBS at Sungkyunkwan University Kangbuk Samsung Hospital. 52 patients(Group O) not greater than stage 2A who had undergone conventional breast surgery during same period were enrolled in this study. The clinicopathologic characteristics, postoperative outcomes, hospital courses, and long-term outcomes including cancer recurrence and 5 year survival were retrospectively compared between two groups. The survivals of all the patients were confirmed with 58.4 month median follow up duration. Results: Tumor sizes were larger in Group O than in Group E(p=0.000). Harvested lymph nodes were more in Group O than in Group E(p=0.000). Postoperative recovery was significantly faster in the Group E; drain was removed earlier(p=0.001) and the postoperative hospital stay was shorter(p=0.001). The mean operation time was significantly longer in the Group E(p=0.000). There were no differences in the operation related morbidity and mortality between the two groups. In comparison of adjuvant therapy, Group O were received more chemotherapy than Group E(p=0.018), but there were no statistical differences of radiotherapy and hormonal therapy between two groups. Subjective cosmetic results were excellent in 63.6% and good in 18.2% more than 1 year after surgery. There was follow-up loss in 3 cases. Cancer-related death occurred in only 1 patient(0.7%) in Group O. The overall 5-year survival rate(5YSR) of the Group O and Group E were 98.2% and 100% , repectively. The disease-free 5YSR of Group O and Group E was 91.3% and 86.9%, repectively. There were no statistical differences on the overall and disease-free 5YSR between the two groups(p=0.446, p=0.205). Cancer recurrence occurred in 5 cases including 2 local recurrences, 2 distant metastases, and 1 second non-breast primary cancer in Group O and 6 cases including 2 local recurrences, 2 regional recurrences, 1 distant metastasis and 1 second non-breast primary cancer in Group E and there was no statistical significance between two groups(p=0.787).
 Conclusions: Although the number and the qualification of the patients were so limited, our data suggest that endoscopy-assisted skin sparing breast surgery for early breast cancer is feasible and safe comparing to conventional breast surgery. We expect the results of the present study to be confirmed by prospective randomized analysis.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4145.

Metabotropic Glutamate Receptor-mediated LTD Involves two Interacting Ca2+ Sensors, NCS-1 and PICK1

There are two major forms of long-term depression (LTD) of synaptic transmission in the central nervous system, which require activation of either N-methyl-D-aspartate receptors (NMDARs) or metabotropic glutamate receptors (mGluRs). In synapses in the perirhinal cortex we have directly compared the Ca2+ signalling mechanisms involved in NMDAR-LTD and mGluR-LTD. Whilst both forms of LTD involve Ca2+ release from intracellular stores the Ca2+ sensors involved are different; NMDAR-LTD involves calmodulin, whilst mGluR-LTD involves the neuronal Ca2+ sensor (NCS) protein NCS-1. In addition, there is a specific requirement for IP3 and PKC as well as protein interacting with C-kinase (PICK-1) in mGluR-LTD. NCS-1 binds directly to PICK1, via its BAR domain, in a Ca2+-dependent manner. Furthermore, the NCS-1-PICK1 association is stimulated by activation of mGluRs, but not NMDARs, and introduction of a PICK1 BAR domain fusion protein specifically blocks mGluR-LTD. Thus, NCS-1 is a component of a novel mechanism involved in mGluR-LTD.

Visual attention deficits contribute to impaired facial emotion recognition in boys with attention-deficit/hyperactivity disorder

The purpose of the present study was to examine whether attention deficits contribute to dysfunctional facial emotion recognition in boys with ADHD. The first hypothesis was that ADHD patients would commit more errors in facial emotion recognition than the control group. The second hypothesis was that attention deficits, which were measured by a computerized continuous performance test (CPT), would be responsible for the errors in facial emotion recognition in boys with ADHD. A revised emotional recognition test (ERT) was used to assess the subjects' ability to recognize emotions. The ADHD diagnostic system (ADS), a computerized continuous performance test (CPT), was used to evaluate attention performance. Subjects with ADHD showed significantly lower scores of contextual understanding than the controls (t=-2.569, df=67, P=0.012). Among age, IQ, and ADS scores, only the score of omission errors on the ADS accounted significantly for the score of contextual understanding in ADHD (effect size 3.4%, P<0.05). Attention deficits in boys with ADHD seemed to account for their difficulty in recognizing facial expressions of emotion. Effective treatment for attention deficits is expected to have a beneficial effect on facial emotion recognition in boys with ADHD.

UV-induced modification of stress distribution in optical fibers and its contribution to Bragg grating birefringence

This paper discusses the importance of stress-induced contributions to the photo-induced birefringence observed in fiber Bragg gratings. Optical tomography measurements are performed in exposed and unexposed fibers to extract the stress profiles induced by UV-writing of fiber Bragg gratings for various exposure levels. A photoelastic analysis and a high-order isoparametric finite elements method are then used to calculate the birefringence caused by stress profile modifications. The results are compared to the birefringence directly measured by spectral analysis of a chirped fiber grating with multiple phase-shifts. We can therefore estimate the fraction of the photo-induced birefringence due to stress-induced anisotropy following UV exposure.

Light-extraction enhancement of vertical-injection GaN-based light-emitting diodes fabricated with highly integrated surface textures

We report on the fabrication of high-efficiency vertical-injection GaN-based light-emitting diodes (LEDs) fabricated with integrated surface textures. An optical ray-tracing simulation shows that the high integration of surface textures can effectively enhance the light-extraction efficiency. The integrated surface textures are fabricated on the top surface of LEDs by generating hexagonal cones on the periodically corrugated surfaces of n-GaN. Compared to reference LEDs without textures, LEDs fabricated with integrated surface textures show an enhancement of the output power by a factor of 2.59, which is in agreement with the calculated results.