Development of a magnetically suspended, tetrahedron-shaped antenna pointing system

A magnetically suspended, tetrahedron-shaped antenna pointing system is proposed for use in a multibeam broadcasting satellite system in the future. The structure of this system is presented, along with its design concept and the functional test results which were obtained in a laser tracking system in the laboratory. According to these results, it has been confirmed that the system has many advantages over conventional systems and excellent performance

Toward Understanding the Origin of Asteroid Geometries: Variety in Shapes Produced by Equal-Mass Impacts

More than a half of asteroids in the main belt have irregular shapes with the ratios of the minor to major axis lengths less than 0.6. One of the mechanisms to create such shapes is collisions between asteroids. The relationship between shapes of collisional outcomes and impact conditions such as impact velocities may provide information on the collisional environments and its evolutionary stages when those asteroids are created. In this study, we perform numerical simulations of collisional destruction of asteroids with radii 50 km and subsequent gravitational reaccumulation using Smoothed Particle Hydrodynamics for elastic dynamics with self-gravity, a model of fracture of rock, and a model of friction of completely damaged rock. We systematically vary the impact velocity from 50 m/s to 400 m/s and the impact angle from 5 degrees to 45 degrees. We investigate shapes of the largest remnants resulting from collisional simulations. As a result, various shapes (bilobed, spherical, flat, elongated, and hemispherical shapes) are formed through equal-mass and low-velocity (50 - 400 m/s) impacts. We clarify a range of the impact angle and velocity to form each shape. Our results indicate that irregular shapes, especially flat shapes, of asteroids with diameters larger than 80 km are likely to be formed through similar-mass and low-velocity impacts, which are likely to occur in the primordial environment prior to the formation of Jupiter.Comment: 11 pages, 15 figures, accepted to Astronomy and Astrophysic

Coexistence of HER2 over-expression and p53 protein accumulation is a strong prognostic molecular marker in breast cancer

INTRODUCTION: Many laboratories are currently evaluating the usefulness of determination of HER2, p53, and Ki67 proliferation indices using immunohistochemical techniques in cancer. Although the available studies suggest that these factors might indeed be helpful in making treatment decisions in cancer patients, their clinical usefulness is still controversial. METHODS: Expression of HER2, p53, and Ki67 was examined by immunohistochemistry in samples of breast tissue from 506 patients with invasive ductal carcinoma, obtained between 1981 and 1999 (median follow up period 82 months), and their significance for prognosis was analyzed. RESULTS: Of the 506 carcinoma tissue samples, 20.1%, 29.0%, and 53.6% were positive for HER2 over-expression, p53 protein accumulation, and Ki67 expression, respectively. Over-expression of HER2 significantly reduced disease free (P = 0.02) and overall survival (P = 0.005). Accumulation of p53 protein significantly decreased disease free (P = 0.01) and overall survival (P = 0.01). Patients with tumors that were positive for both HER2 and p53 relapsed and died within a significantly shorter period of time after surgery (P = 0.0001 and P < 0.0001, respectively). In multivariate analysis, patients with both HER2 and p53 positive tumors had considerably decreased overall survival (P = 0.04), as did patients with larger tumor size and positive lymph node status. CONCLUSION: The findings of the present study indicate that the coexistence of HER2 over-expression and p53 protein accumulation is a strong prognostic molecular marker in breast cancer

Prevention of contrast-induced nephropathy by chronic pravastatin treatment in patients with cardiovascular disease and renal insufficiency

SummaryBackgroundContrast-induced nephropathy (CIN) is known to increase morbidity and mortality of cardiovascular disease. Recent studies have shown statins prevented CIN after contrast media exposure, but optimal statin type and dosage are still unknown.PurposeThe aims of the present study were to evaluate whether chronic pravastatin treatment before scheduled coronary angiography or percutaneous coronary intervention could reduce the incidence of CIN and to elucidate the factors related to CIN in patients with renal insufficiency.MethodsWe studied 431 consecutive patients with renal insufficiency. One hundred ninety-four patients were receiving pravastatin treatment as standard chronic treatment of hypercholesterolemia. Serum creatinine levels were measured at baseline (pre-procedure) and within 48h after contrast media exposure (peak post-procedure). CIN was defined as an increase in the serum creatinine values of ≥25% or ≥0.5mg/dl after contrast media exposure. Logistic regression analysis was performed to evaluate the important factors related to CIN using four variables: age, pravastatin, pre-procedure serum creatinine, and contrast volume.ResultsCIN was observed in 36 patients (8.4%). Patients without pravastatin (p<0.01), high level pre-procedure serum creatinine (p<0.01), and high contrast volume (p=0.034) had a significantly higher incidence of CIN. Logistic regression analysis revealed that pravastatin treatment (χ2=6.549, p=0.011, odds ratio=0.34), pre-procedure serum creatinine (χ2=6.294, p=0.009, odds ratio=2.78), and contrast volume (χ2=4.484, p=0.034, odds ratio=1.01) were independently related to the decreased risk of CIN.ConclusionsChronic pravastatin treatment before contrast media exposure was important for preventing CIN in patients with renal insufficiency. Also, reducing the dose of contrast media was important for preventing CIN in patients with high-baseline serum creatinine levels