Influence of fetal calf serum on differentiation of mesenchymal stem cells to chondrocytes during expansion

Mesenchymal stem cells (MSCs) should be expanded in vitro while maintaining their multilineage potential before differentiation to one mesenchymal lineage for application to regeneration therapy. The effect of fetal calf serum (FCS) on undesirable differentiation during subcultivations for the expansion was investigated. The expression level of the aggrecan gene, which is a marker of chondrogenic differentiation, gradually and markedly increased during the subcultivations of MSCs with the addition of 10% FCS and without additional cytokines. The percentage of cells positive for CD90 and CD166, which are markers of MSCs, decreased, and the percentage of large polygonal cells and the average cell adhesion area increased during the expansion. There was a marked difference in the increase in the aggrecan expression level between the two expansion cultures employing different FCS lots, although their proliferation rates were almost the same. The decrease in FCS concentration resulted in a higher percentage of CD90(+)CD166(+) cells, a lower percentage of large polygonal cells, and a lower level of aggrecan expression. Consequently, FCS components could stimulate MSC differentiation to chondrocytes and a lower concentration could decrease this differentiation.     

Simplified flocculation model for inorganic and polymer flocculants

Simulation of the flocculation process using both inorganic and polymer flocculants is very difficult because there are many factors that influence the process. In this study, a model that enables the visual understanding of the qualitative trends of the flocculation system using both inorganic and polymer flocculants is proposed. It is a simplified one-dimensional model that expresses flocculation under various additive manners of the flocculant. Various kinds of thought experiments as well as experimental runs with model flocculants were carried out based on the model; the results demonstrate that the model can express many empirical qualitative trends of flocculation.     

Phosphorescent cyclometalated complexes for efficient blue organic light-emitting diodes

Phosphorescent emitters are extremely important for efficient organic light-emitting diodes (OLEDs), which attract significant attention. Phosphorescent emitters, which have a high phosphorescence quantum yield at room temperature, typically contain a heavy metal such as iridium and have been reported to emit blue, green and red light. In particular, the blue cyclometalated complexes with high efficiency and high stability are being developed. In this review, we focus on blue cyclometalated complexes. Recent progress of computational analysis necessary to design a cyclometalated complex is introduced. The prediction of the radiative transition is indispensable to get an emissive cyclometalated complex. We summarize four methods to control phosphorescence peak of the cyclometalated complex: (i) substituent effect on ligands, (ii) effects of ancillary ligands on heteroleptic complexes, (iii) design of the ligand skeleton, and (iv) selection of the central metal. It is considered that novel ligand skeletons would be important to achieve both a high efficiency and long lifetime in the blue OLEDs. Moreover, the combination of an emitter and a host is important as well as the emitter itself. According to the dependences on the combination of an emitter and a host, the control of exciton density of the triplet is necessary to achieve both a high efficiency and a long lifetime, because the annihilations of the triplet state cause exciton quenching and material deterioration.     

Thermal MIMO controller for setpoint regulation and load disturbance rejection

The thermal interaction problem of a multi-input multi-output (MIMO) temperature process is caused by the temperature gradient through the plant. Generally, industrial controllers are used for the decentralized control and do not use a process mathematical model. In many cases, trial-and-error tuning is required for solving the problem. The present paper introduces a MIMO thermal model and the decoupling PID control strategy. The decoupling control and its shortcomings are described from the perspective of the user. An improved strategy based on a robust observer is developed. For industrial implementation, this observer is quite simple because only the first-order model given by the decoupling model is implemented. The program code is simple for the microprocessor of a low-cost commercialized controller. In addition, a hunting rejection method based on the observer is presented. The present paper applies the method to the twin screw extruder in order to verify the effectiveness of the proposed strategy. The proposed method has been successfully to solve the interaction problem for MIMO temperature process.     

Land cover change detection with a cross‐correlogram spectral matching algorithm

Timely extraction of reliable land cover change information is increasingly needed at a wide continuum of scales. Few methods developed from previous studies have proved to be robust when noise, changes in atmospheric and illumination conditions, and other scene‐ and sensor‐dependent variables are present in the multitemporal images. In this study, we developed a new method based on cross‐correlogram spectral matching (CCSM) with the aim of identifying interannual land cover changes from time‐series Normalized Difference Vegetation Index (NDVI) data. In addition, a new change index is proposed with integration of two parameters that are measured from the cross‐correlogram: the root mean square (RMS) and (1?R _max), where R _max is the maximum correlation coefficient in a correlogram. Subsequently, a method was proposed to derive the optimal threshold for judging ‘change’ or ‘non‐change’ with the acquired change index. A pilot study was carried out using SPOT VGT‐S images acquired in 1998 and 2000 at Xianghai Park in Jilin Province. The results indicate that CCSM is superior to a traditional Change Vector Analysis (CVA) when noise is present with the data. Because of an error associated with the ground truthing data, a more comprehensive assessment of the developed method is still in process using better ground truthing data and images at a larger time interval. It is worth noting that this method can be applied not only to NDVI datasets but also to other index datasets reflecting surface conditions sampled at different time intervals. In addition, it can be applied to datasets from different satellites without the need to normalize sensor differences.     

Tradeoffs between quantization and packet loss in networked control of linear systems

In this paper, we consider to derive the coarsest memoryless quantizer which can stabilize a single-input discrete-time linear time-invariant system with stochastic packet loss in the sense of stochastic quadratic stability. We show that the upper bound of the coarseness is strictly given by the packet loss probability and the unstable poles of the plants. We furthermore deal with permissible dead-zone width around the origin of the quantizers and time-varying finite quantizers in order to realize control using finite quantization steps.     

A High-Performance, Pipelined, FPGA-Based Genetic Algorithm Machine

Accelerating a genetic algorithm (GA) by implementing it in a reconfigurable field programmable gate array (FPGA) is described. The implemented GA features: random parent selection, which conserves selection circuitry; a steady-state memory model, which conserves chip area; survival of fitter child chromosomes over their less-fit parent chromosomes, which promotes evolution. A net child chromosome generation rate of one per clock cycle is obtained by pipelining the parent selection, crossover, mutation, and fitness evaluation functions. Complex fitness functions can be further pipelined to maintain a high-speed clock cycle. Fitness functions with a pipeline initiation interval of greater than one can be plurally implemented to maintain a net evaluated-chromosome throughput of one per clock cycle. Two prototypes are described: The first prototype (c. 1996 technology) is a multiple-FPGA chip implementation, running at a 1 MHz clock rate, that solves a 94-row × 520-column set covering problem 2,200× faster than a 100 MHz workstation running the same algorithm in C. The second prototype (Xilinx XVC300) is a single-FPGA chip implementation, running at a 66 MHZ clock rate, that solves a 36-residue protein folding problem in a 2-d lattice 320× faster than a 366 MHz Pentium II. The current largest FPGA (Xilinx XCV3200E) has circuitry available for the implementation of 30 fitness function units which would yield an acceleration of 9,600× for the 36-residue protein folding problem.     

Design parameter evaluation based on human operation for tip mechanism of forceps manipulator using surgical robot simulation

We proposed a design method for pediatric surgical robots that evaluates the workspace and view information in computer simulator before the actual robot is developed. In this study, we investigated a suturing task in a virtual environment using forceps manipulators with different mechanical parameters. We reproduced the surgical workspace for congenital esophageal atresia and measured the working volume and invisible area to obtain suitable parameters for the suturing task. We also calculated the suitable mechanical parameters using Pareto optimal solution method and verified the mechanical parameters in Pareto optimal solution. We verified from the experimental results that there is a trade-off between the working volume and invisible area during the suturing task. Moreover, we determined from the calculation results that the mechanical design of the forceps manipulator is influenced by the invisible area during the suturing task. Finally, we confirmed that it is possible to obtain suitable parameters for surgical robots using the proposed method.     

Morphological abstraction of thyroid tumor cell nuclei using morphometry with factor analysis

Various morphonuclear studies by digital image analysis have successfully been applied to quantify the nuclear morphology, including chromatin distribution pattern, in cytology of various organs; however, the majority of past reports have not shown correlation between the quantitative data by digital image analysis and cytological findings in practical diagnosis. In this report, we present the usefulness of morphological abstraction to combine the objective data and subjective observation in cytological diagnosis. Randomly selected, 100 cells in each Papanicolaou-stained ABC smear samples of 39 benign and malignant thyroid tumor cases were studied. Gray-level image data provided seven parameters for nuclear size, four parameters for nuclear shape, and 16 parameters showing the nuclear chromatin patterns from high-dimensional texture analysis of using co-occurrence and run-length matrices. To statistically abstract nuclear morphology, factor analysis was used. Factor analysis classified morphological nuclear characters as abstraction parameter into five abstract parameters composed of nuclear size, shape, heterogeneity, and contrast and homogeneity of chromatin pattern. The nuclei of papillary carcinoma showed larger size, more irregular shape, and higher contrast of chromatin pattern than those of the benign group. The follicular carcinomas have larger nucleus in each cell and more monotonous chromatin pattern among cells in each case than those of the benign group. Morphological abstraction by morphometry with factor analysis may provide a practical approach to the detection of the underlying characteristics of nuclear morphology in aspiration biopsy cytology.     

Terahertz Frequency-Domain Spectroscopy of Low-Pressure Acetonitrile Gas by a Photomixing Terahertz Synthesizer Referenced to Dual Optical Frequency Combs

A terahertz (THz) frequency synthesizer based on photomixing of two near-infrared lasers with a sub-THz to THz frequency offset is a powerful tool for spectroscopy of polar gas molecules due to its broad spectral coverage; however, its frequency accuracy and resolution are relatively low. To tune the output frequency continuously and widely while maintaining its traceability to a frequency standard, we developed a photomixing THz synthesizer phase-locked to dual optical frequency combs (OFCs). While the phase-locking to dual OFCs ensured continuous tuning within a spectral range of 120 GHz, in addition to the traceability to the frequency standard, use of a broadband uni-traveling carrier photodiode for photomixing enabled the generation of CW-THz radiation within a frequency range from 0.2 to 1.5 THz. We demonstrated THz frequency-domain spectroscopy of gas-phase acetonitrile CH₃CN and its isotope CH₃ ¹³CN in the frequency range of 0.600–0.720 THz using this THz synthesizer. Their rotational transitions were assigned with a frequency accuracy of 8.42?×?10^?8 and a frequency resolution of 520 kHz. Furthermore, the concentration of the CH₃CN gas at 20 Pa was determined to be (5.41?±?0.05)?×?10¹⁴ molecules/cm³ by curve fitting analysis of the measured absorbance spectrum, and the mixture ratio of the mixed CH₃CN/CH₃ ¹³CN gas was determined to be 1:2.26 with a gas concentration of 10¹⁴–10¹⁵ molecules/cm³. The developed THz synthesizer is highly promising for high-precision THz-FDS of low-pressure molecular gases and will enable the qualitative and quantitative analyses of multiple gases.