Transparent glass-ceramics for thermal management application: achievement of optical transparency and high thermal conductivity

Oxide glass is an industrial material with advantages such as optical transparency and shaping ability of the melt, but at the same time, it is a bad conductor of heat due to its disordered structures. Therefore, heat dissipation in glass components often becomes a problem and its applications to the thermal management has been limited to use as a heat insulator. To break this mold and to apply it to fields, e.g., transparent sealing materials, for which low thermal conductive glasses and organic polymers have been conventionally used, we fabricated an MgO-dispersed glass-ceramics in our previous work. It comprises MgO crystal and glass matrix and their reflective indices are matched, leading to optical transparency and improvement in thermal conductivity. Here we investigate the atomic-scale structures in the MgO-dispersed glass-ceramics by nuclear magnetic resonance, etc. and attempt to further improve the thermal conductivity and the transparency. As a result, we show an MgO-dispersed glass-ceramic with a thermal conductivity of 3.3 W (m⁻¹ K⁻¹), corresponding to 300% of that of the glass matrix, high optical transparency, and glass transition. This report highlights that our strategies pave the way for development of novel transparent, functional glass-ceramics.

Oxide glass is an industrial material with advantages such as optical transparency and shaping ability of the melt, but at the same time, it is a bad conductor of heat due to its disordered structures.     

Effects of stress‐shielding on the dynamic viscoelasticity and ordering of the collagen fibers in rabbit Achilles tendon

We investigated the effects of stress‐shielding on both viscoelastic properties and microstructure of collagen fibers in the Achilles tendon by proton double‐quantum filtered (¹H‐DQF) NMR spectroscopy. The right hind‐limbs of 20 Japanese white rabbits were immobilized for 4 weeks in a cast with the ankle in plantarflexion. Dynamic viscoelasticity of the Achilles tendons was measured using a viscoelastic spectrometer. Proton DQF NMR signals were analyzed to determine the residual dipolar coupling of bound water molecules in the Achilles tendons. Both the dynamic storage modulus (E′) and dynamic loss modulus (E″) decreased significantly in the Achilles tendons of the stress‐shielding group. The results of the ¹H‐DQF NMR examination demonstrated significantly reduced residual dipolar coupling in the Achilles tendons of this same group. The disorientation of collagen fibers by stress‐shielding should contribute to degradation of the dynamic storage and loss moduli. The alterations of the collagen fiber orientation that contributed to the function of tendinous tissue can be evaluated by performing an analysis of ¹H DQF NMR spectroscopy. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1708–1712, 2013     

Acute coronary syndrome: evaluation of detection capability using non-electrocardiogram-gated parenchymal phase CT imaging

Purpose

To evaluate the capability to detect acute coronary syndrome (ACS) by using non-electrocardiogram-gated parenchymal phase CT imaging.

Materials and methods

Of 962 consecutive patients who underwent emergent coronary angiography for suspected ACS, 32 with ACS who underwent CT ≤24 h before angiography and 15 without ACS who underwent CT ≤24 h before or after angiography were included. Parenchymal phase was acquired at 100-s scan delay. The presence of a myocardial perfusion defect (MPD) on the left ventricle (a decrease of >20 HU) and its capability to detect ACS were evaluated. Results were compared with laboratory findings.

Results

MPD was detected in 29 of 32 ACSs. The sensitivity, specificity, and positive and negative predictive values were 91 % (29/32), 93 % (14/15), 97 % (29/30), and 82 % (14/17), respectively. The sensitivities of ST- and non-ST-elevation ACSs were 89 % (16/18) and 93 % (13/14), respectively, without significant difference (P > 0.99). Of the CT-detectable ACS, non-ST-elevation on the electrocardiogram and a normal creatine kinase-myocardial band were observed in 41 % (12/29) and 24 % (7/29), respectively.

Conclusion

ACS is highly detectable even using conventional parenchymal phase CT imaging. Therefore, even when CT is non-gating, radiologists should carefully evaluate the heart to avoid overlooking ACS.

     

Hepatocyte growth factor: from diagnosis to clinical applications

Hepatocyte growth factor (HGF), initially identified and molecularly cloned as a potent mitogen of primary cultured hepatocytes, has multiple activities in a variety of tissues during the course of development and also in various disease states. HGF plays key roles in the attenuation of disease progression as an intrinsic repair factor. It is also evident that HGF levels are regulated under different conditions, for example, during the course of pregnancy, aging, and disease. This review focuses on the levels of HGF in normal and pathophysiological situations and examines the relationships between HGF levels and disease, disease stage, and disease prognosis. The clinical potential of HGF as a treatment for subjects with various diseases is also given attention.     

Castration-resistant prostate cancer without metastasis at presentation may achieve cancer-specific survival in patients who underwent prior radical prostatectomy

International Urology and Nephrology - Radical prostatectomy (RP) is relatively better oncological outcomes in patients with prostate cancer (PCa). However, the incidence of castration-resistant...     

Evaluation of interleukin-12-induced interferon-y production in vitro by peripheral blood mononuclear cells in patients with chronic liver disease

BACKGROUND/AIMS: Interleukin-12 plays an important role in anti-tumor immune response by induction of interferon-gamma production by T cells and NK cells, and by activation of cytotoxic T cells and NK cells. We evaluated interleukin-12-induced interferon-gamma production as one of the immunological markers of patients with chronic liver diseases. METHODOLOGY: Interleukin-12-induced interferon-gamma production was measured in vitro in peripheral blood mononuclear cells from 28 hepatocellular carcinoma patients, 10 liver cirrhosis patients, 14 chronic hepatitis patients and 16 healthy individuals. RESULTS: The hepatocellular carcinoma patients exhibited a reduced interleukin-12 responsiveness for interferon-gamma production compared to the liver cirrhosis patients, the chronic hepatitis patients and the healthy individuals. The reduced interferon-gamma production seemed to roughly reflect clinical stage in the hepatocellular carcinoma patients. The interferon-gamma production correlated with neither alpha-fetoprotein nor protein induced by vitamin K absence II. CONCLUSIONS: The level of interleukin-12-induced interferon-gamma production by peripheral blood mononuclear cells in the patients with hepatocellular carcinoma was significantly lower than that in the patients with liver cirrhosis which is thought to be a premalignant state. The measurement of interferon-gamma production may be useful in evaluating severity of chronic liver disease from an immunological point of view.