An Optimal Design Method for CMOS Even-Stage Ring Oscillators Containing Latches

This paper describes a design method for complementary metal oxide semiconductor (CMOS) ring oscillators composed of even-stage inverters. First, we propose a quantitative method to evaluate oscillation stability for an even-stage ring oscillator with a CMOS latch. The method uses static noise margin analysis to evaluate the static random access memory (SRAM) cell\u27s data storage stability, by observing the similarity between the oscillator and SRAM cell circuitry. Next, the method is extended to oscillators with multiple latches. Finally, by analyzing oscillation stability using this method, we find that the range of stable oscillation conditions can be drastically widened by adding multiple single-channel latch circuits, and also by an appropriate design of their polarities and insertion positions. We also clarify through Monte Carlo simulations, that the optimized oscillator circuit is robust under process, voltage and temperature fluctuations and device characteristic variations

An Optimal Design Method for Even-Stage Ring Oscillators with a CMOS Latch

This paper describes an analysis of oscillation conditions in CMOS ring oscillators composed of even-stage inverters. A design method optimizing the oscillator\u27s operational margin based on this analysis is also described. We have found that stable oscillation margin analysis for this type of circuit is basically equivalent to the Static Noise Margin (SNM) analysis for SRAM write/read operations. Using this concept, we have established a design method that determines the optimal circuit design parameters to ensure stable oscillation.2008 International Conference on Solid State Devices and Materials (SSDM 2008), September 23-26, 2008, Tsukuba, Ibaraki, Japa

Effect of connective tissue growth factor (CCN2/CTGF) on proliferation and differentiation of mouse periodontal ligament-derived cells

Background: CCN2/CTGF is known to be involved in tooth germ development and periodontal tissue remodeling, as well as in mesenchymal tissue development and regeneration. In this present study, we investigated the roles of CCN2/CTGF in the proliferation and differentiation of periodontal ligament cells (murine periodontal ligament-derived cell line: MPL) in vitro. Results: In cell cultures of MPL, the mRNA expression of the CCN2/CTGF gene was stronger in sparse cultures than in confluent ones and was significantly enhanced by TGF-β. The addition of Recombinant CCN2/CTGF (rCCN2) to MPL cultures stimulated DNA synthesis and cell growth in a dose-dependent manner. Moreover, rCCN2 addition also enhanced the mRNA expression of alkaline phosphatase (ALPase), type I collagen, and periostin, the latter of which is considered to be a specific marker of the periosteum and periodontium; whereas it showed little effect on the mRNA expression of typical osteoblastic markers, e.g., osteopontin and osteocalcin. Finally, rCCN2/CTGF also stimulated ALPase activity and collagen synthesis. Conclusion: These results taken together suggest important roles of CCN2/CTGF in the development and regeneration of periodontal tissue including the periodontal ligament.</p

Mechanical stretch increases CCN2/CTGF expression in anterior cruciate ligament-derived cells

Anterior cruciate ligament (ACL)-to-bone interface serves to minimize the stress concentrations that would arise between two different tissues. Mechanical stretch plays an important role in maintaining cell-specific features by inducing CCN family 2/connective tissue growth factor (CCN2/CTGF). We previously reported that cyclic tensile strain (CTS) stimulates alpha 1(I) collagen (COL1A1) expression in human ACL-derived cells. However, the biological function and stress-related response of CCN2/CTGF were still unclear in ACL fibroblasts. In the present study, CCN2/CTGF was observed in ACL-to-bone interface, but was not in the midsubstance region by immunohistochemical analyses. CTS treatments induced higher increase of CCN2/CTGF expression and secretion in interface cells compared with midsubstance cells. COL1A1 expression was not influenced by CCN2/CTGF treatment in interface cells despite CCN2/CTGF stimulated COL1A1 expression in midsubstance cells. However, CCN2/CTGF stimulated the proliferation of interface cells. Our results suggest that distinct biological function of stretch-induced CCN2/CTGF might regulate region-specific phenotypes of ACL-derived cells

Ultrasonographic characteristics of small hepatocellular carcinoma.

The ultrasonographic characteristics of hepatocellular carcinomas (HCC) were investigated. Four typical features of HCCs, "mosaic internal echo pattern", "halo", "lateral shadow" and "posterior echo enhancement", were not recognized in minute HCCs smaller than 2 cm in diameter. These characteristics developed as the tumors grew. Only hypoechoic space-occupying lesions can be considered as small HCCs. In differentiating small HCCs from hypoechoic non-malignant space-occupying lesions in the cirrhotic liver, the ratios of short to long dimensions of the lesions seemed to be important since the ratios of HCCs were significantly larger than those of non-malignant lesions. The fact that 3 hyperechoic small HCCs could not be diagnosed even by celiac arteriography has suggested to us that ultrasonically guided biopsies should be performed in order to differentiate from small hemangiomas. Serum alpha-fetoprotein (AFP) levels of 1/3 of the patients with HCCs were below 100 ng/ml, indicating that it is impossible to detect small HCCs only by measuring serum AFP.</p

Demonstration of a spherical plasma mirror for the counter-propagating kilojoule-class petawatt LFEX laser system

A counter-propagating laser-beam platform using a spherical plasma mirror was developed for the kilojoule-class petawatt LFEX laser. The temporal and spatial overlaps of the incoming and redirected beams were measured with an optical interferometer and an x-ray pinhole camera. The plasma mirror performance was evaluated by measuring fast electrons, ions, and neutrons generated in the counter-propagating laser interaction with a Cu-doped deuterated film on both sides. The reflectivity and peak intensity were estimated as ∼50% and ∼5 × 1018 W/cm2, respectively. The platform could enable studies of counter-streaming charged particles in high-energy-density plasmas for fundamental and inertial confinement fusion research.Kojima S., Abe Y., Miura E., et al. Demonstration of a spherical plasma mirror for the counter-propagating kilojoule-class petawatt LFEX laser system. Optics Express 30, 43491 (2022); https://doi.org/10.1364/oe.475945