Photoluminescent characteristics of Ni-catalyzed GaN nanowires

The authors report on time-integrated and time-resolved photoluminescence (PL) of GaN nanowires grown by the Ni-catalyst-assisted vapor-liquid-solid method. From PL spectra of Ni-catalyzed GaN nanowires at 10 K, several PL peaks were observed at 3.472, 3.437, and 3.266 eV, respectively. PL peaks at 3.472 and 3.266 eV are attributed to neutral-donor-bound excitons and donor-acceptor pair, respectively. Furthermore, according to the results from temperature-dependent and time-resolved PL measurements, the origin of the PL peak at 3.437 eV is also discussed. (c) 2006 American Institute of Physics.X1147sciescopu

Production of Transgenic Cloned Miniature Pigs with Membrane-bound Human Fas Ligand (FasL) by Somatic Cell Nuclear Transfer

Cell-mediated xenograft rejection, including NK cells and CD8+ CTL, is a major obstacle in successful pig-to-human xenotransplantation. Human CD8+ CTL and NK cells display high cytotoxicity for pig cells, mediated at least in part by the Fas/FasL pathway. To prevent cell-mediated xenocytotoxicity, a membrane-bound form of human FasL (mFasL) was generated as an inhibitor for CTL and NK cell cytotoxicity that could not be cleaved by metalloproteinase to produce putative soluble FasL. We produced two healthy transgenic pigs harboring the mFasL gene via somatic cell nuclear transfer (SCNT). In a cytotoxicity assay using transgenic clonal cell lines and transgenic pig ear cells, the rate of CD8+ CTL-mediated cytotoxicity was significantly reduced in transgenic pig's ear cells compared with that in normal minipig fetal fibroblasts. Our data indicate that grafts of transgenic pigs expressing membrane-bound human FasL control the cellular immune response to xenografts, creating a window of opportunity to facilitate xenograft survival

Fibre composites for high pressure pipeline repairs, in-air and subsea: an overview

In 2001 it was reported that in North America alone, corrosion to the Oil & Gas pipeline distribution network cost approximately $2-3.3 billion per annum with 10% of that cost being associated with actual failure of the pipeline. In addition pipelines are also susceptible to erosion and mechanical damage producing further losses in pipe structural integrity. This results in high maintenance costs, possibility of adverse environmental consequences and the costly interruption to product transportation and distribution. The cost and technical challenges of adequately addressing repair are significant and greatly increase for underwater applications particularly with increasing water depth. It therefore induces the need of searching for alternative repair techniques involving new advanced materials for ease of installation and application against adverse environmental effects in the long run. Fibre composite materials provide excellent advantages over conventional metals in engineering practices for many decades. These advantages make fibre composite suitable candidate for effective repair technology. This paper provides a comprehensive review on the recent development and future prospect of using these materials for in-air and underwater pipeline external repairs. Various aspects of technical knowhow; benefits and shortcomings of the repair considerations are also presented

A study on the change in the characteristics of the gait of elderly people when somatosensory stimulation was applied to their ankle joint

The gait is the most complicated, habitual, and involuntary activity of humans and is a result of the cooperation of the central and peripheral nervous systems that harmoniously mobilize the sensory receptors, nervous system, and muscles. A sensory signal binds to a somatosensory system proprioceptor to obtain information on posture. This study was designed to analyze the change in the characteristics of a gait when stimulation is applied in the somatosensory system that controls the balance of the body. A result of the GRF obtained from the force plate and gyroscope signals from the sensor attached on ankle joint were obtained to compare the change before and after the somatosensory stimulation. The result of this study proved a potential of somatosensory stimulation in improving balance, which could be used in studies on the balance of positions and gait improvement

Effects of muscular response for the intensity of vibratory stimulus applied on the ankle tendon

The present study was conducted to measure the individual threshold value for the somatosensory system of the human body, the thresholds value of vibratory stimulus were assessed through the ascent and descent methods. In the interests of the attainment of this study`s goal, comparing the thresholds value measured and change of state of the muscles when applied on the ankle tendon connected to muscles, changes in threshold measurement accuracy due to the differences in measuring methods were discussed. The experiment was conducted by constructing systems to stimulate somethetic sensibility by vibratory stimulus, ultrasound imaging system and EMG system. Five adult males were involved in this experiment. According to the results of experiments, the threshold value of somatosensory stimulation measured by the ascent method was greater than the threshold values measured by the descent method. And the muscular response to the somatosensory stimulation applied to the tibialis anterior tendon showed a larger rate of change with the ascending stimulus than with the descending stimulus. The results of this study could serve as a basis to discuss the reliability of the measurement method of the human body’s individual threshold value for the somatosensory system through the ascent and descent methods and can be used as reference data for the integration and performance threshold measurement methods

A study on the changes in gait characteristics by applying sub-threshold vibration stimulus in the ankle

This study was conducted to suggest the potential use of a mechanical vibration stimulus in the ankle to correct gait abnormalities. As for the mechanical vibration stimulus, different locations and durations are suggested based on the detection results of real-time gait patterns. 5 young males participated in this study. They were asked to perform assigned gait tasks when either a threshold or sub-threshold stimulus was applied in the tibialis anterior and Achilles tendon. The analysis results of gait cycle and muscle activity showed the changes on gait cycle, the activity pattern of used muscle for gait and the movement pattern of the ankle were observed based on the applied locations of vibration stimulus. Also, the result of sub-threshold stimulus showed similar effects as that of threshold stimulus. As such, the mechanical vibration stimulus was considered to affect gait by being adjusted its characteristics and local stimulus also would affect human body systemically. The result of this study can be used as basic data for the correction of individual’s specific gait abnormality and rehabilitation using vibration stimulus

Evaluation of the Clinical and Radiographic Effectiveness of Treating Peri-Implant Bone Defects With a New Biphasic Calcium Phosphate Bone Graft: A Prospective, Multicenter Randomized Controlled Trial

PURPOSE: Biphasic calcium phosphate (BCP), a widely used biomaterial for bone regeneration, contains synthetic hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), the ratio of which can be adjusted to modulate the rate of degradation. The aim of this study was to evaluate the clinical and radiographic benefits of reconstructing peri-implant bone defects with a newly developed BCP consisting of 40% β-TCP and 60% HA compared to demineralized bovine bone mineral (DBBM). METHODS: This prospective, multicenter, parallel, single-blind randomized controlled trial was conducted at the periodontology departments of 3 different dental hospitals. Changes in clinical (defect width and height) and radiographic (augmented horizontal bone thickness) parameters were measured between implant surgery with guided bone regeneration (GBR) and re-entry surgery. Postoperative discomfort (severity and duration of pain and swelling) and early soft-tissue wound healing (dehiscence and inflammation) were also assessed. Data were compared between the BCP (test) and DBBM (control) groups using the independent RESULTS: Of the 53 cases included, 27 were in the test group and 26 were in the control group. After a healing period of 18 weeks, the full and mean resolution of buccal dehiscence defects were 59.3% (n=16) and 71.3% in the test group and 42.3% (n=11) and 57.9% in the control group, respectively. There were no significant differences between the groups in terms of the change in mean horizontal bone augmentation (test group: -0.50±0.66 mm vs. control groups: -0.66±0.83 mm, CONCLUSION: The GBR procedure with the newly developed BCP showed favorable clinical, radiographic, postoperative discomfort-related, and early wound healing outcomes for peri-implant dehiscence defects that were similar to those for DBBM