Genetic Diversity of Insulin Resistance and Metabolic Syndrome

A key in the etiology of a cluster of metabolic syndrome such as hyperglycemia, dyslipidemia, and obesity is known for insulin resistance, which is becoming a major global public health problem. Extensive studies have revealed many genetic factors for both insulin resistance and the components of metabolic syndrome. Advanced modern genotyping methods including genome-wide association studies and next-generation sequencing have allowed for the identification of both common and rare genetic variants related to these chronic disease-associated traits. Multiple genotype–phenotype studies are also needed to identify new and accurate genetic biomarkers in these conditions. The purpose of this chapter is to present genetic variants related to the pathogenesis of metabolic syndrome and insulin resistance and is to review the relevance between insulin resistance and metabolic syndrome clusters in terms of genetic diversity

Assessment of portal image resolution improvement using an external aluminum target and polystyrene electron filter

Abstract Background In this study, an external 8 mm thick aluminum target was installed on the upper accessory tray mount of a medical linear accelerator head. The purpose of this study was to determine the effects of the external aluminum target beam (Al-target beam) on the portal image quality by analyzing the spatial and contrast resolutions. In addition, the image resolutions with the Al-target beams were compared with those of conventional 6 megavoltage (MV) images. Methods The optimized Al-target beam was calculated using Monte Carlo simulations. To validate the simulations, the percentage depth dose and lateral profiles were measured and compared with the modeled dose distributions. A PTW resolution phantom was used for imaging to assess the image resolution. The spatial resolution was quantified by determining the modulation transfer function. The contrast resolution was determined by a fine contrast difference between the 27 measurement areas. The spatial and contrast resolutions were compared with the those of conventional portal images. Results The measured and calculated percentage depth dose of the Al-target beam were consistent within 1.6%. The correspondence of measured and modelled profiles was evaluated by gamma analysis (3%, 3 mm) and all gamma values inside the field were less than one. The critical spatial frequencies (f 50) of the images obtained with the Al-target beam and conventional imaging beam were 0.745 lp/mm and 0.451 lp/mm, respectively. The limiting spatial frequencies (f 10) for the Al-target beam image and the conventional portal image were 2.39 lp/mm and 1.82 lp/mm, respectively. The Al-target beam resolved the smaller and lower contrast objects better than that of the MV photon beam. Conclusion The Al-target beams generated by the simple target installation method provided better spatial and contrast resolutions than those of the conventional 6 MV imaging beam

Investigation of Interfacial Adhesion between the Top Ends of Carbon Nanotubes

Understanding the interfacial forces of carbon nanotubes (CNTs) is fundamental to the development of electromechanical systems based on the contact of CNTs. However, experimental studies on the adhesion properties between CNTs are scarce despite the remarkable contact quality of CNTs. Here, we present an experimental investigation of the adhesion between the top ends of aligned, self-adjusted CNTs using a CNT-integrated microelectromechanical actuator. The pull-out and pull-in behaviors of the contact as a function of the applied force by the actuator are precisely identified by measuring the contact resistance between the CNTs. The adhesion between the top ends of individual CNTs is extracted from the measured adhesive strength between the CNT arrays, and it agrees with the theoretical values of the van der Waals interactions. By exploiting the adhesion of the CNT-to-CNT contact, a programmable and reliable microelectromechanical switching device is demonstrated. Our results offer design strategies for diverse CNT-based nano- and microelectromechanical devices that need repeatable contacting interfaces

Micromachined Resonant Frequency Tuning Unit for Torsional Resonator

Achieving the desired resonant frequency of resonators has been an important issue, since it determines their performance. This paper presents the design and analysis of two concepts for the resonant frequency tuning of resonators. The proposed methods are based on the stiffness alteration of the springs by geometrical modification (shaft-widening) or by mechanical restriction (shaft-holding) using micromachined frequency tuning units. Our designs have advantages in (1) reversible and repetitive tuning; (2) decoupled control over the amplitude of the resonator and the tuning ratio; and (3) a wide range of applications including torsional resonators. The ability to tune the frequency by both methods is predicted by finite element analysis (FEA) and experimentally verified on a torsional resonator driven by an electrostatic actuator. The tuning units and resonators are fabricated on a double silicon-on-insulator (DSOI) wafer to electrically insulate the resonator from the tuning units. The shaft-widening type and shaft-holding type exhibit a maximum tuning ratio of 5.29% and 10.7%, respectively

Development of MEMS Multi-Mode Electrostatic Energy Harvester Based on the SOI Process

Multi-vibrational-mode electrostatic energy harvesters are designed and micro-machined utilizing a simple silicon-on-insulator (SOI) wafer-based process. Enhanced adaptability to various vibrational environments is achieved in the proposed design by using serpentine springs attached to the fishbone-shaped inertial mass. The experimental results show that the developed device could convert an input vibration of 6 g at 1272 Hz to 2.96, 3.28, and 2.30 μW for different vibrational directions of 0°, 30°, and 45° with respect to a reference direction, respectively, when all serpentine springs are identical. An alternative device design using serpentine springs with different stiffnesses between x- and y-axes exhibited resonance frequencies at 1059 and 1635 Hz for an input vibrational direction of 45° and acceleration amplitude of 4 g, successfully generating 0.723 and 0.927 μW of electrical power at each resonance, respectively

Identification of antigenic peptide recognized by the anti-JL1 leukemia-specific monoclonal antibody from combinatorial peptide phage display libraries

PURPOSE: In the present study an antigen-mimetic peptide of the anti-JL1 leukemia-specific monoclonal antibody (mAb) was identified and characterized. METHODS: From combinatorial peptide phage display libraries displaying the random linear heptapeptides and dodecapeptides, we selected clones with affinity to anti-JL1 mAb through repeated rounds of panning on a mAb-coated ELISA plate. The antigenicity and immunogenicity of the peptide epitopes were then studied using chemically synthesized peptides. RESULTS: The selected clones had the LXPSIP consensus sequence. Two synthetic peptides LPPSIPFGLTVGGGGS and LLPSIPNQAYLGGGGS specifically reacted with anti-JL1 mAb in ELISA. These two peptides were found to inhibit the interaction between anti-JL1 mAb and JL1 antigen-positive Molt-4 cells. Although the immune sera raised against the keyhole limpet hemocyanin-conjugated peptides failed to react with Molt-4 cells, it showed strong reactivity to the peptide epitope. However, one mAb raised by peptide immunization successfully bound to Molt-4 cells. CONCLUSION: An epitope-mimetic peptide of anti-JL1 mAb was found using combinatorial peptide phage display libraries. It induced strong humoral response against itself, but only a limited fraction of this humoral response was cross-reactive with the original JL1 antigen

Reversible and Continuous Latching Using a Carbon Internanotube Interface

Mechanical multistability is greatly beneficial in microelectromechanical systems because it offers multiple stable positioning of movable microstructures without a continuous energy supply. Although mechanical latching components based on multistability have been widely used in microsystems, their latching positions are inherently discrete and the number of stable positions is quite limited because of the lithographical minimum feature size limit of microstructures. We report a novel use of aligned carbon nanotube (CNT) arrays as latching elements in a movable micromechanical device. This CNT-array-based latching mechanism allows stable latching at multiple latching positions, together with reversible and bidirectional latching capabilities. The latching element with integrated CNTs on the sidewalls of microstructures can be adopted for diverse microelectromechanical systems that need precise positioning of movable structures without the necessity of continuous power consumption