Optimum Design of Step Cascades for Uranium Enrichment by Gaseous Diffusion Process

When the optimization of a step cascade is carried out directly on the basis of an exact formula, the calculus of minimization of a multi-variable function is essential. The numerical calculation is very complex and a brief estimation becomes impossible as the number of steps increases, because the number of variables in the calculus amounts to (2ₘ₋1) in all for an m-steps cascade. In this paper an approximate formula of good feasibility and sufficient accuracy is proposed for the determination of the number of stages and interstage flow rate required for the plant of uranium enrichment by gaseous diffusion process. By using an approximate formula, the minimization of multi-variable function in the optimization of step cascades is able to be avoided. The applicability of the proposed method is verified by the calculation of a typical plant for uranium enrichment

On Acoustic Dispersion In MF₆-type Molecules

Available data on relaxation times in MF₆-type molecule have been incompatible with analytical approaches. Then, we performed experiments on the acoustic dispersion of SF₆, WF₆ and UF₆ gases by using a double crystal ultrasonic interferometer. It was revealed that the available data on WF₆ are not acceptable, and the relaxation time of UF₆ is less than 0.027 μsec・atm at a temperature below 68°C

Morphological and Biochemical Changes During Aging and Photoaging of the Skin of C57BL/6J Mice

The differences between the dorsal skin of 11- and 16-week-old C57BL/6J mice were examined morphologically and biochemically. The dermis of the 16-week-old mice was thinner than that of the 11-week-old mice due to decreases in the amounts of soluble collagen and elastin. Next, the changes in dorsal skin exposed to UVA irradiation for 8 weeks (576 J/cm2) were examined in 3 (younger)- and 8 (older)-week-old C57BL/6J mice. The thickness of the dermis was not significantly different between the UVA-irradiated and control mice in either the younger or older group. The increase in the amount of collagen was related to the increase in the level of soluble collagen in the younger mice. In contrast, it was related to the increase in the level of insoluble collagen in the older mice. In the UVA-irradiated older mice, the activity of the latent form of MMP-13 was significantly higher than that in the control mice. These results suggest that aging and UVA-induced photoaging in the skin are histologically and biochemically different phenomena

Time-course expression profiles of hair cycle-associated genes in male mini rats after depilation of telogen-phase hairs.

Jcl:WistarTGN(ARGHGEN)1Nts rat (Mini rat) is a growth hormone (GH)-deficient transgenic rat. The hair cycle in the dorsal skin of male Mini rats enters a long-lasting telogen phase after eights weeks of age, but depilation can induce a transient hair cycle again. In this study, a time-course profiling of genes expression was done on the dorsal skin of male Mini rats along the progression of depilation-induced hair cycle using DNA microarray analysis. As a result, 1,215 probe sets including 1,171 hair cycle-related ones showed more than 3-fold changes in expression compared with that in before-depilation telogen phase. The present data will contribute to elucidating the mechanisms of hair cycle regulation and should lead to the identification of novel molecular targets for hair growth and/or depilation agents

Digital mammography, cancer screening: Factors important for image compression

The use of digital mammography for breast cancer screening poses several novel problems such as development of digital sensors, computer assisted diagnosis (CAD) methods for image noise suppression, enhancement, and pattern recognition, compression algorithms for image storage, transmission, and remote diagnosis. X-ray digital mammography using novel direct digital detection schemes or film digitizers results in large data sets and, therefore, image compression methods will play a significant role in the image processing and analysis by CAD techniques. In view of the extensive compression required, the relative merit of 'virtually lossless' versus lossy methods should be determined. A brief overview is presented here of the developments of digital sensors, CAD, and compression methods currently proposed and tested for mammography. The objective of the NCI/NASA Working Group on Digital Mammography is to stimulate the interest of the image processing and compression scientific community for this medical application and identify possible dual use technologies within the NASA centers

Quantitative Evaluation of Liver Function with Use of Gadoxetate Disodium-enhanced MR Imaging

Purpose: To determine whether liver function correlating with indocyanine green (ICG) clearance could be estimated quantitatively from gadoxetate disodium-enhanced magnetic resonance (MR) images. Materials and Methods: This retrospective study was approved by the institutional review board, and the requirement for informed consent was waived. Twenty-three consecutive patients who underwent an ICG clearance test and gadoxetate disodium-enhanced MR imaging with the same parameters as were used for a preoperative examination were chosen. The hepatocellular uptake index (HUI) from liver volume (V(L)) and mean signal intensity of the liver on contrastenhanced T1-weighted images with fat suppression (L(20)) and mean signal intensity of the spleen on contrastenhanced T1-weighted images with fat suppression (S(20)) on 3D gradient-echo T1-weighted images with fat suppression obtained at 20 minutes after gadoxetate disodium (0.025 mmol per kilogram of body weight) administration was determined with the following equation: V(L)[(L(20)/S(20)) 2 1]. The correlation of the plasma disappearance rate of ICG (ICG-PDR) and various factors derived from MR imaging, including HUI, iron and fat deposition in the liver and spleen, and spleen volume (V(S)), were evaluated with stepwise multiple regression analysis. The difference between the ratio of the remnant HUI to the HUI of the total liver (rHUI/HUI) and ratio of the liver remnant V(L) to the total V(L)(rV(L)/V(L)) was evaluated in four patients who had segmental heterogeneity of liver function. Results: HUI and V(S) were the factors significantly correlated with ICG-PDR (R = 0.87). The mean value and its 95% confidence interval were 0.18 and 0.01 to 0.34, respectively, for the following calculation: (rHUI/HUI) 2 (rV(L)/V(L)). Conclusion: The liver function correlating with ICG-PDR can be estimated quantitatively from the signal intensities and the volumes of the liver and spleen on gadoxetate disodium-enhanced MR images, which may improve the estimation of segmental liver function. (C) RSNA, 2011ArticleRADIOLOGY. 260(3):727-733 (2011)journal articl

Suppression of the contrast of ribs in chest radiographs by means of massive training artificial neural network

ABSTRACT We developed a method for suppression of the contrast of ribs in chest radiographs by means of a massive training artificial neural network (MTANN). The MTANN is a trainable highly nonlinear filter that can be trained by using input chest radiographs and the corresponding teacher images. We used either the soft-tissue image or the bone image obtained by use of a dual-energy subtraction technique as the teacher image for suppression of ribs in chest radiographs. When the soft-tissue images were used as the teacher images, the MTANN directly produced a "soft-tissue-image-like" image where the contrast of ribs was suppressed. When the bone images were used as the teacher images, the MTANN was able to produce a "bone-image-like" image, and then was subtracted from the corresponding chest radiograph to produce a bone-subtracted image where ribs are suppressed. Thus, the two kinds of rib-suppressed images, i.e., the soft-tissue-image-like image and the bone-subtracted image, could be produced by use of the MTANNs trained with two different teacher images. We applied each of the two trained MTANNs to non-training chest radiographs to investigate the difference between the processed images. The results showed that the contrast of ribs in chest radiographs almost disappeared, and was reduced to less than 10% in both processed images. The contrast of ribs was reduced slightly better in the soft-tissue-image-like images than in the bone-subtracted images, whereas soft-tissue opacities such as lung vessels and nodules were maintained better in the bone-subtracted images. Therefore, the use of the bone images as the teacher images for training the MTANN has produced better rib-suppressed images where soft-tissue opacities were substantially maintained. A method for rib suppression using the MTANN would be useful for radiologists as well as CAD schemes in detection of lung diseases such as nodules in chest radiographs

Accelerating effects of silk fibroin on wound healing in hairless descendants of Mexican hairless dogs

Abstract: We examined the safety of silk fibroin in the subcutaneous tissues. In addition, we macroscopically and histopathologically evaluated its healing effect on the full-thickness wounds in hairless dogs. We prepared 3 types of matrices including amorphous silk fibroin films, and á-and â-type silk fibroin powder. No toxicity was found in the sites injected with silk fibroin solutions. Macroscopically, silk fibroin films had accelerating effects on wound repair, as compared with occlusive dressings (dried porcine skin and hydrocolloid dressings). Histopathological examinations revealed that silk fibroin films facilitate reepithelialization and the formation of granulation tissues, collagens and elastic fibers. The sites treated with the á-type silk fibroin powder were faster in wound repair than those treated with the â-type silk fibroin powder. The á-type silk fibroin powder absorbed excessive exudate. Microscopically, there are epidermal and dermal regeneration in the sites treated with the á-type silk fibroin powder. These results show that silk fibroin is inert in biological tissues, indicating excellent biocompatibility. Silk fibroin films facilitate reepithelialization, remodeling of connective tissues and collagenization. The á-type fibroin powder is a wound dressing that regulates excessive exudate from the wound and provides a proper moist environment. These results suggest that silk fibroin is a useful dressing material in veterinary clinical medicine