5,540 research outputs found
Absolute Decay Counting of Sm-146 and Sm-147 for Early Solar System Chronology
No full textSm-Nd chronometers use Sm-146 and Sm-147 to determine the ages of major events in the early Solar System. Their half-lives are the most important nuclear parameters determining the accuracy of chronometry. However, the Sm-146 half-life is not wellestablished: the published values differ by similar to 30%, which results in significant uncertainties in the Solar System timeline. We are re-measuring the half-lives of Sm-146 and Sm-147 using decay energy spectroscopy and metallic magnetic calorimeters to improve the accuracy of the Sm-Nd chronometers. We report recent experimental results from our first measurement of a Sm-147 source, as well as status and plans for experiments on Sm-146.11Nsciescopu
Digital subtraction CT angiography based on efficient 3D registration and refinement
No full textA novel method for fast, automatic 3D digital subtraction CT angiography (DS-CTA) is presented to generate artifact-free angiograms. The proposed method consists of two steps: 3D registration to align a CT image to the CT angiography (CTA) image and subtraction-and-refinement to extract blood vessels only. For efficient and accurate 3D registration in the first step, an normalized mutual information (NMI) based algorithm is adopted, and its fast version is developed by introducing a new measure. To further improve the subtracted image quality in the second step, a novel 3D refinement algorithm is suggested to effectively remove unwanted residuals. Experimental results of seven clinical CT/CTA head datasets demonstrate that cerebral vessels are well extracted from CTA images with almost no loss. The typical processing time is 3-9 min depending on the image size in a PC with a 2.4 GHz CPU. (C) 2004 Elsevier Ltd. All rights reserved
A Microcalcification Detection Using Multi-Layer Support Vector Machine in Korean Digital Mammogram
No full textA computer-aided diagnosis (CAD) system has
been examined to reduce the effort of radiologist. In the
mammogram, it is helpful to improve the diagnostic accuracy
of malignancy microcalcifications in early stage of detecting
breast cancer. In this paper, we propose a microcalcification
detection method using multi-layer support vector machine
(SVM) classifiers to determine whether microcalcifications are
malignant or benign tumors. The proposed microcalcification
detection is divided into two steps, each of which uses a SVM
classifier. First, potential ROIs (Region of interest) those are
suspicious as malignant tumors are detected as a coarse detection
level. And then, each ROI is classified whether it is malignant
or not. The proposed algorithm is applied to the Korean
digital mammogram. Experimental result showed that the
proposed method would outperform conventional method
using ANN (artificial neural networks).This paper is supported by the development of digital
CAD system project (02-PJ3-PG6-EV06-0002) of Ministry
of Health and Welfare in The Republic of Korea.전기및전자공학
Yeast metabolism in fresh and frozen dough : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand
No full textAuthor also known as SM LovedayFresh bakery products have a very short shelf life, which limits the extent to which manufacturing can be centralised. Frozen doughs are relatively stable and can be manufactured in large volumes, distributed and baked on-demand at the point of sale or consumption. With appropriate formulation and processing a shelf life of several months can be achieved.Shelf life is limited by a decline in proofing rate after thawing, which is attributed to a) the dough losing its ability to retain gas and b) insufficient gas production, i.e. yeast activity. The loss of shelf life is accelerated by delays between mixing and freezing, which allow yeast cells the chance to ferment carbohydrates.This work examined the reasons for insufficient gas production after thawing frozen dough and the effect of pre-freezing fermentation on shelf life. Literature data on yeast metabolite dynamics in fermenting dough were incomplete. In particular there were few data on the accumulation of ethanol, a major fermentation end product which can be injurious to yeast.Doughs were prepared in a domestic breadmaker using compressed yeast from a local manufacturer and analysed for glucose, fructose, sucrose, maltose and ethanol. Gas production after thawing declined within 48 hours of frozen storage. This was accelerated by 30 or 90 minutes of fermentation at 30;C prior to freezing.Sucrose was rapidly hydrolysed and yeast consumed glucose in preference to fructose. Maltose was not consumed while other sugars remained. Ethanol, accumulated from consumption of glucose and fructose, was produced in approximately equal amounts to CO2, indicating that yeast cells metabolised reductively.Glucose uptake in fermenting dough followed simple hyperbolic kinetics and fructose uptake was competitively inhibited by glucose. Mathematical modelling indicated that diffusion of sugars and ethanol in dough occurred quickly enough to eliminate solute gradients brought about by yeast metabolism
Global spliceosome activity regulates entry into cellular senescence
No full textCellular senescence is a state of permanent growth arrest that can ultimately contribute to aging. Senescence can be induced by various stressors and is associated with a myriad of cellular functions and phenotypic markers. Alternative splicing is emerging as a critical contributor to senescence and aging. However, it is unclear how the composition and function of the spliceosome are involved in senescence. Here, using replicative and oxidative stress-induced senescence models in primary human fibroblasts, we report a common shift in the expression of 58 spliceosomal genes at the pre-senescence stage, prior to the detection of senescence-associated β-galactosidase (SA-β-gal) activity. Spliceosomal perturbation, induced by pharmacologic and genetic inhibition of splicesomal genes, triggered cells to enter senescence, suggesting a key role as a gatekeeper. Association analysis of transcription factors based on the 58 splicesomal genes revealed Sp1 as a key regulator of senescence entry. Indeed, Sp1 depletion suppressed the expression of downstream spliceosomal genes (HNRNPA3, SRSF7, and SRSF4) and effectively induced senescence. These results indicate that spliceosomal gene sets, rather than a single spliceosomal gene, regulate the early transition into senescence prior to SA-β-gal expression. Furthermore, our study provides a spliceosome signature that may be used as an early senescence marker
Research of the Microrheology and Phase Transition Phenomenon of the Fundamental Organic Thin Films using Quartz Crystal
No full textPlastic work approach for surface defect prediction in the hot bar rolling process
No full textIn this study, a numerical technique was developed to study the effect of processing parameters on instability of the steel during five passes hot bar rolling process. For this a processing map developed based on the plastic work approach was used with finite element analyses to judge occurrence of instability during the process. The effect of roll geometry and processing temperature on hot rolled bars was examined with the help of a parametric study by employing the numerical technique developed. Based on this parametric study, the improved roll pass design and initial processing temperature were determined, respectively, for reducing flow instability during the process. The laboratory rolling mill was used to validate the numerical results. It was found that with the increase of the initial temperature in the process the less flow instability was observed compared to the change of the roll geometry introduced at each pass under the present investigation condition. It was found that the current numerical technique implemented will be useful in identifying the important parameters governing the formation of surface cracks in the multi-stage hot bar rolling process. (C) 2007 Elsevier B.V. All rights reserved.The authors wish to acknowledge the grant of National
Research Laboratory program of the Ministry of Science and
Technology through KOSEF (no. R0A-2006-000-10240-0)The
financial and technical supports from the POSCO technical
research laboratory were very much appreciated as well
Mass-producible replication of highly hydrophobic surfaces from plant leaves
No full textMany plant leaves found in nature are known to exhibit a characteristic of superhydrophobicity ('lotus leaf effect'). The present study proposes a mass-production method of highly hydrophobic surfaces by simply replicating the highly hydrophobic plant leaf surfaces in two steps: the first step of making a nickel mould via electroforming and the second step of replication via a UV-nanoimprint lithography. Making a nickel mould, either a plant leaf or its negative polymer replica is used as a mandrel in electroforming, and final products become positive or negative polymer replicas of a plant leaf, respectively. It is found that the nickel-mould making using the plant leaf as a mandrel is quite successful and the final products in the form of a positive replica are better than those in the form of a negative replica in terms of replication quality and hydrophobicity. Contact angle values of the positive replicas are less than those of the natural leaves' surfaces by only 2 degrees-5 degrees.X1180sciescopu
Effects of intrinsic hydrophobicity on wettability of polymer replicas of a superhydrophobic lotus leaf
No full textThe present work suggests a mass-producible and large-scale fabrication method of superhydrophobic polymeric surfaces by means of material processing equipments which can maximize productivity and cost effectiveness. We fabricated two types of polymeric lotus leaf replicas using a nickel mold, i.e. R1 from intrinsically hydrophobic polydimethylsiloxane by means of polymer casting (PC) and R2 from an intrinsically hydrophilic UV-curable photopolymer by means of UV-nanoimprint lithography ( UV-NIL). In the case of R1 from PC, although the nano-scaled structures were not well reproduced, the contact angle (CA) was remarkably high and the sliding angle ( SA) was also close to that of the original lotus leaf, resulting in a superhydrophobic surface. In contrast to R1, in the case of R2 from UV-NIL, the nano-scaled structures as well as micro-scaled structures were also relatively well reproduced and the CA was increased noticeably by around 99. in comparison to a flat photopolymer. However, unexpectedly, the SA of R2 was much higher than that of R1. This work provides useful tips of polymeric material selection for the industrial mass production of the superhydrophobic polymer surface.X1187sciescopu
sj-docx-1-ine-10.1177_15910199221107440 - Supplemental material for A simplified cranial cavity model to understand the relationship between intracranial pressure and dural sinus pressure
No full textSupplemental material, sj-docx-1-ine-10.1177_15910199221107440 for A simplified cranial cavity model to understand the relationship between intracranial pressure and dural sinus pressure by KB Lee, MH Kim, J-T Yoon, Y Song, B Kwon, SM Hwang, JH Choi and DH Lee in Interventional Neuroradiology</p
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