A probabilistic framework based on hidden markov model for fiducial identification in image-guided radiation treatments

Fiducial tracking is a common target tracking method widely used in image-guided procedures such as radiotherapy and radiosurgery. In this paper, we present a multifiducial identification method that incorporates context information in the process. We first convert the problem into a state sequence problem by establishing a probabilistic framework based on a hidden Markov model (HMM), where prior probability represents an individual candidate's resemblance to a fiducial; transition probability quantifies the similarity of a candidate set to the fiducials' geometrical configuration; and the Viterbi algorithm provides an efficient solution. We then discuss the problem of identifying fiducials using stereo projections, and propose a special, higher order HMM, which consists of two parallel HMMs, connected by an association measure that captures the inherent correlation between the two projections. A novel algorithm, the concurrent viterbi with association (CVA) algorithm, is introduced to efficiently identify fiducials in the two projections simultaneously. This probabilistic framework is highly flexible and provides a buffer to accommodate deformations. A simple implementation of the CVA algorithm is presented to evaluate the efficacy of the framework. Experiments were carried out using clinical images acquired during patient treatments, and several examples are presented to illustrate a variety of clinical situations. In the experiments, the algorithm demonstrated a large tracking range, computational efficiency, ease of use, and robustness that meet the requirements for clinical use.      

Q开关532nm激光与强脉冲光治疗咖啡斑疗效对比

目的:对比Q开关532nm激光与强脉冲光治疗咖啡斑疗效.方法:分别用两种方法治疗咖啡斑各30例,观察临床疗效、不良反应及病人满意度.结果:Q开关532nm激光咖啡斑30例,其中9例显效,13例有效,8例无效.强脉冲光治疗治疗30例,其中6例显效,15例有效,9例无效.两种方法无一例出现疤痕.结论:两者临床疗效及不良反应无显著差异.但因强脉冲光治疗时疼痛感稍轻、治疗周期短、不耽误工作而更受欢迎.     

利用极化方位角特征的高分辨极化SAR目标增强研究

针对高分辨极化SAR目标增强问题,提出一种利用极化方位角特征的增强方法.首先,利用圆极化法提取极化SAR图像像素点的极化方位角特征;其次,通过"方位角归零化"获得像素点在零度极化方位角下的散射矩阵值.对比归零化前、后目标及杂波区域内部像素点极化特性聚集程度的差异,阐述了利用极化方位角特征进行目标增强的原理;再次,统计获得目标及杂波区域的平均极化特性,采用非线性最优化方法实现了目标增强;最后,基于ADTS全极化SAR实测数据验证了本文方法具有优良的目标增强性能.     

基于FPGA的基带编码器设计

本文介绍了基带码的相关内容,包括基带码的分类、常用的基带码以及CCITT对码型的建议,详细讲叙了单极性非归零码、双极性非归零码、单极性归零码、双极性归零码、差分码、交替极性码几种码型的特点.根据码型变换规则在FPGA平台上设计编码器,采用Verilog HDL语言进行了设计,并在QuartusⅡ软件上实现了设计仿真验证了编码器的功能.     

Low‐Power 512‐Bit EEPROM Designed for UHF RFID Tag Chip

In this paper, the design of a low‐power 512‐bit synchronous EEPROM for a passive UHF RFID tag chip is presented. We apply low‐power schemes, such as dual power supply voltage (VDD=1.5 V and VDDP=2.5 V), clocked inverter sensing, voltage‐up converter, I/O interface, and Dickson charge pump using Schottky diode. An EEPROM is fabricated with the 0.25 μm EEPROM process. Power dissipation is 32.78 μW in the read cycle and 78.05 μW in the write cycle. The layout size is 449.3 μm × 480.67 μm.     

中心局搬迁中SDH传输网的割接组网方案

本文介绍了某中心局搬迁中SDH传输网的割接组网方案.     

Older versus younger treatment-seeking smokers: differences in smoking behavior, drug and alcohol use, and psychosocial and physical functioning

Quitting smoking benefits older individuals, yet few recent studies have described older smokers. The goal of this paper was to test a series of hypotheses about differences between smokers aged 50 years or older (50+) and those younger than age 50 (<50) presenting to the same treatment facility during 2002-2004 for participation in two randomized clinical trials: one exclusively for smokers aged 50+, and a second open to smokers aged 18 or older. As predicted, smokers aged 50+ were more tobacco dependent, had better psychological functioning, and had poorer physical functioning than those aged <50. Contrary to predictions, we found no differences in motivation to quit cigarette smoking or in alcohol use. Women aged 50+ were less likely to report marijuana use than women aged <50, and less likely than men to receive a positive diagnosis for alcohol abuse. Despite higher scores on measures of tobacco dependence, older smokers were less likely to be diagnosed as tobacco dependent or as having tobacco withdrawal using DSM-IV criteria. Rates of DSM-IV alcohol abuse and dependence were high in both age groups but were higher for smokers aged <50. We found no striking differences between studies in reasons for exclusion, but in both the proportion of individuals excluded due to current antidepressant use was high. Implications for the assessment and treatment of older adults are discussed.     

Evaluation of exopolysaccharide production by Leuconostoc mesenteroides strains isolated from wine

ABSTRACT:  Exopolysaccharide (EPS)-producing lactic acid bacteria are responsible for the alteration of wine and other fermented beverages. The potential to produce EPS was investigated for Leuconostoc mesenteroides strains isolated from Spanish grape must and wine. Most strains were able to produce EPS from sucrose containing media. Based on their EPS-producing phenotype and on their EPS monosaccharide composition, the L. mesenteroides strains analyzed could be arranged in 2 groups. One group comprises mucoid strains producing a glucan polymer, and the other group includes strains producing a fructan polymer. The presence of a glucosyltransferase encoding gene in the glucan producing L. mesenteroides strains was assayed by PCR. Two primer sets, PF1-PF8 and GTFF-GTFR, were used to amplify internal fragment of known glucosyltransferase genes. None of the glucan-producing strains gave a positive amplicon by the primer sets used. Therefore, new tools need to be developed to broaden the range of potentially spoiling agents detected by PCR in fermented beverages.     

Protection of deoxyribose and DNA from degradation by using aqueous extracts of several wild plants

BACKGROUND: Aqueous extracts of 48 herbal plants were obtained via alternative extraction protocols, and were assayed for their capacity to protect deoxyribose and DNA itself from degradation (or, conversely, for their capacity to promote DNA degradation), using electrophoresis as analytical tool. RESULTS: For a given (constant) volume of extract, deoxyribose protection ranged from 14.13 ± 1.35% (mean ± SD) inhibition by dwarf mallow powder infusion, up to 106.51 ± 15.93% inhibition by avocado powder infusion. DNA protection was tested at two extract concentrations, and was slightly greater at the higher concentration. Pro‐oxidant effects were essentially absent. CONCLUSION: The anti‐oxidative roles of plants upon deoxyribose and DNA displayed by our experimental results were rather promising with regards to practical applications of those plants, viz. as ingredients in the formulation of nutraceutical beverages and/or foods. Copyright © 2007 Society of Chemical Industry     

用于个体防刺服的UHMWPE纤维针刺毡的性能研究

对UHMWPE(超高分子量聚乙烯)纤维针刺毡单层样品的撕破强力、顶破强力和多层样品的抗刺穿能力进行了测试,结果表明:随着单层UHMWPE纤维针刺毡面密度的增加,试样的顶破强力增大;在20~55℃范围内,随着试样预处理温度升高,顶破强力和抗刺穿能力皆增强,但是试样的撕破强力则无这种变化趋势。