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Routine rectal retroflexion during colonoscopy has a low yield for neoplasia

World Journal of Gastroenterology 2008年第42期14卷 6503-6505页

作者： Abdo Saad douglas Kevin Rex Department of Medicine Division of Gastroenterology/Hepatology Indiana University School of Medicine Indianapolis IN 46202 United States

AIM： To investigate the value of retroflexion in detecting neoplasia in the distal rectum. METHODS： This was a prospective observational study performed in an academic endoscopy unit. Consecutive patients undergoing colonoscopy had careful forward viewing of the distal rectum by retroflexion. Of 1502 procedures, 1076 （72%） procedures were performed with a 140^o angle of view colonoscope and 426 （28%） were performed with a 170^o angle of view colonoscope. The outcome measurement was the yield of neoplasia in the distal rectum detected by forward viewing vs retroflexion. RESULTS： A total of 1502 patients, including 767 （51%） females and 735 （49%） males, with mean age of 58.8 ± 12.5 years were enrolled. Retroflexion was successful in 1411 （93.9%） patients, unsuccessful or not performed because the rectum appeared narrow in 91 （6.1%）. Forty patients had a polyp detected in the distal rectal mucosa. Thirty-three were visible in both the forward and retroflexed view （25 hyperplastic, 8 adenomatous）. Seven polyps were visualized only by retroflexion （6 hyperplastic sessile polyps, one 4 mm sessile tubular adenoma）. There was no significant difference in information added by retroflexion with 140^o vs 170^o angle of view instrument. CONCLUSION： To our knowledge, this is the largest reported evaluation of retroflexion in the rectum. Routine rectal retroflexion did not detect clinically important neoplasia after a careful forward examination of the rectum to the dentate line. Since retroflexion has risks and may cause discomfort, theuse of routine retroflexion should be at the discretion of the endoscopist.

关键词： Colonoscopy Colorectal polyps Retroflexion Rectum

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ANALYSIS OF THE IMPACT OF SAMPLE SIZE, ATTRIBUTE VARIANCE AND WITHIN-SAMPLE CHOICE DISTRIBUTION ON THE ESTIMATION ACCURACY OF MULTINOMIAL LOGIT MODELS USING SIMULATED DATA

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Journal of Systems Science and Systems Engineering 2018年第6期27卷 771-789页

作者： Minhui Zeng Ming Zhong John douglas Hunt Engineering Research Center for Transportation safety ofMOE Wuhan University of Technology Wuhan China School of Traffic and Transportation Engineering Changsha University of Science & Technology China National Engineering Research Center for Water Transportation Safety China Department of Civil and Environmental Engineering University of Waterloo Ontario Canada Department of Civil Engineering University of Calgary Alberta Canada

Literature review indicates that sample size, attribute variance and within-sample choice distribution of alternatives are important considerations in the estimation of multinomial logit （MNL） models, but their impacts on the estimation accuracy have not been systematically studied. Therefore, the objective of this paper is to provide an empirical examination to the above issues through a set of simulated discrete choice preference and rank ordered preference datasets. In this paper, the utility coefficients, alternative specific constants （ASCs）, and the mean and standard deviation of the four attributes for a set of seven hypothetical alternatives are specified as a priori. Then, synthetic datasets, with varying sample size, attribute variance and within-sample choice distribution are simulated. Based on these datasets, the utility coefficients and ASCs of the specified MNLs are re-estimated and compared with the original values specified as the priori. It is found that （1） the estimation accuracy of utility parameters increases as the sample size increases; （2） the utility coefficients can be re-estimated with reasonable accuracy, but the estimates of the ASCs are confronted with much larger errors; （3） as the variances of the alternative attributes increase, the estimation accuracy improves significantly; and （4） as the distribution of chosen choices becomes more balanced across alternatives within sample datasets, the hit-ratio decreases. The results indicate that （a） under a similar setting presented in this paper, a large sample consisting of a few thousand observations （3000 - 4000） may be needed in order to provide reasonable estimates for utility coefficients, particularly for ASCs; （b） a larger, but realistic attribute space is preferred in the stated preference survey design; and （c） choice datasets with unbalanced ＂chosen＂ choice frequency distribution is preferred, in order to better capture the elasticity between the ＂perceived utility＂ associated wit

关键词： Sample size attribute variance within-sample choice distribution simulated data

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Analysis of the methylation pattern of six gene promoters in sperm of men with abnormal protamination

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Asian Journal of Andrology 2011年第2期13卷 342-346页

作者： Laszlo Nanassy douglas T Carrell Andrology and IVF Laboratories Department of Surgery University of Utah School of Medicine Salt Lake City UT 84108 USA Department of Obstetrics and Gynecology University of Utah School of Medicine Salt Lake City UT 84208 USA Department of Physiology University of Utah School of Medicine Salt Lake City UT 84108 USA

It has recently been shown that alteration of the methylation pattern of imprinted genes is associated with different types of male infertility. The objective of our study was to investigate the methylation pattern of selected gene promoters in sperm of patients with abnormal protamine replacement. The promoters of OCT4, SOX2, NANOG, HOXC11, miR-17and CREMwere analyzed using bisulfite sequencing and the percentage of DNA methylation was compared between patients with an abnormal protamine l/protamine 2 （P1/ P2） ratio and normozoospermic controls. No significant quantitative differences were found between groups of patients with either an abnormally high or low P1/P2 ratio compared to normal controls. However, two individual samples from infertile subjects （2/20, 10%） showed an altered methylation pattern for the CREMgene promoter that was not found in control samples. These two samples had a significantly higher （P〈0.05） promoter methylation （5.58 and 4.23%, respectively） compared to the control group （0.46%）. In conclusion, in our pilot study, extreme methylations defects were not seen broadly in severely infertile men. However, two patients exhibited altered methylation of the CREMgene, which may be either causative or a result of abnormal protmaine replacement.

关键词： Epigenetic gene promoter male infertility methylation protamine

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Patient interest in video recording of colonoscopy:A survey

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World Journal of Gastroenterology 2010年第4期16卷 458-461页

作者： Meghana Raghavendra douglas K Rex Division of Gastroenterology/Hepatology Indiana University Medical CenterIndianapolisIN 46202United States

AIM:To find if patients are interested in obtaining a video recording of their colonoscopy ***:We conducted a survey of outpatients presenting for colonoscopy regarding their interest in obtaining a video recording of their ***:Two hundred and forty-eight patients(mean age 57.9 years;57% male) were *** hundred and one patients(81%) were interested in obtaining a video *** significant predictors of patients' interest in the video recording were *** reading a brief educational paragraph explaining missed lesions during colonoscopy,135 patients(54%) were more interested in having a video recording,and none were less *** hundred and fifty-six patients(63%) were willing to pay for a video *** multivariable analyses,younger age was predictive of willingness to pay for a video *** history of colorectal cancer and a family history of colorectal cancer were predictive of willingness to pay a greater ***:Patients undergoing colonoscopy expressed substantial interest in obtaining a videorecording of their *** of missing lesions during colonoscopy increased interest in having a videorecording.

关键词： Colonoscopy Video recording Survey

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Redefining the possibility of digital Earth and geosciences with spatial cloud computing

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International Journal of Digital Earth 2013年第4期6卷 297-312页

作者： Chaowei Yang Yan Xu douglas Nebert Center of Intelligent Spatial Computing for Water/Energy Sciences George Mason UniversityFairfaxVAUSA Microsoft Research RedmondWAUSA Federal Geographic Data Committee RestonVAUSA

Global challenges(such as economy and natural hazards)and technology advancements have triggered international leaders and organizations to rethink geosciences and Digital Earth in the new *** next generation visions pose grand challenges for infrastructure,especially computing *** gradual establishment of cloud computing as a primary infrastructure provides new capabilities to meet the *** paper reviews research conducted using cloud computing to address geoscience and Digital Earth needs within the context of an integrated Earth *** also introduce the five papers selected through a rigorous review process as exemplar research in using cloud capabilities to address the *** literature and research demonstrate that spatial cloud computing provides unprecedented new capabilities to enable Digital Earth and geosciences in the twenty-first century in several aspects:(1)virtually unlimited computing power for addressing big data storage,sharing,processing,and knowledge discovering challenges,(2)elastic,flexible,and easy-to-use computing infrastructure to facilitate the building of the next generation geospatial cyberin-frastructure,CyberGIS,CloudGIS,and Digital Earth,(3)seamless integration environment that enables mashing up observation,data,models,problems,and citizens,(4)research opportunities triggered by global challenges that may lead to breakthroughs in relevant fields including infrastructure building,GIScience,computer science,and geosciences,and(5)collaboration supported by cloud computing and across science domains,agencies,countries to collectively address global challenges from policy,management,system engineering,acquisition,and operation aspects.

关键词： EarthCube CloudGIS eScience Earthscience interoperability

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Comment on “A numerical investigation of the acoustic mode waves in a deviated borehole penetrating a transversely isotropic formation”

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Science China(Physics,Mechanics & Astronomy) 2016年第8期59卷 89-90页

作者： Steve A.Horne douglas Miller CanYun Wang Chevron Energy Technology Corporation London El4 4HA UK Massachusetts Institute of Technology Boston 02139 USA CNPC Logging Company Ltd Beijing 102206 China

In the paper"A numerical investigation of the acoustic mode waves in a deviated borehole penetrating a transversely isotropic formation"by Liu et al.[1]numerical experiments are reported for a dipole sonic logging scenario with a deviated borehole penetrating a VTI anisotropic *** such a situation it is important to clearly define the meaning of group and phase velocities as this has led to much confusion in the literature as discussed by Miller,Horne and Walsh[2].

关键词： penetrating Comment on isotropic borehole logging sonic confusion dipole deviation clearly

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Texture-based latent space disentanglement for enhancement of a training dataset for ANN-based classification of fruit and vegetables

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Information Processing in Agriculture 2023年第1期10卷 85-105页

作者： Khurram Hameed douglas Chai Alexander Rassau School of Engineering Edith Cowan University270 Joondalup DriveJoondalup WA 6027PerthAustralia

The capability of Convolutional Neural Networks(CNNs)for sparse representation has significant application to complex tasks like Representation Learning(RL).However,labelled datasets of sufficient size for learning this representation are not easily *** unsupervised learning capability of Variational Autoencoders(VAEs)and Generative Adversarial Networks(GANs)provide a promising solution to this issue through their capacity to learn representations for novel data samples and classification *** this research,a texture-based latent space disentanglement technique is proposed to enhance learning of representations for novel data samples.A comparison is performed among different VAEs and GANs with the proposed approach for synthesis of new data *** different VAE architectures are considered,a single layer dense VAE and a convolution based VAE,to compare the effectiveness of different architectures for learning of the *** GANs are selected based on the distance metric for disjoint distribution divergence estimation of complex representation learning *** proposed texture-based disentanglement has been shown to provide a significant improvement for disentangling the process of representation learning by conditioning the random noise and synthesising texture rich images of fruit and vegetables。

关键词： Information Maximisation(IM) Fruit and vegetables classification Representation Learning(RL) Variational Autoencoder(VAE) Generative Adversarial Network (GAN) Latent space disentanglement

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Breast cancer resistance protein(BCRP/ABCG2):its role in multidrug resistance and regulation of its gene expression

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Chinese Journal of Cancer 2012年第2期31卷 73-99页

作者： Takeo Nakanishi douglas D.Ross Department of Membrane Transport and Biopharmaceutics Kanazawa University School of Pharmaceutical SciencesKanazawa 920-1192Japan University of Maryland Greenebaum Cancer Center the Departments of Medicine Pathology and Pharmacology and Experimental TherapeuticsUniversity of Maryland School of Medicineand the Baltimore VA Medical CenterBaltimoreMaryland 21201USA

Breast cancer resistance protein(BCRP)/ATP-binding cassette subfamily G member 2(ABCG2) is an ATP-binding cassette(ABC) transporter identified as a molecular cause of multidrug resistance(MDR) in diverse cancer *** physiologically functions as a part of a self-defense mechanism for the organism;it enhances elimination of toxic xenobiotic substances and harmful agents in the gut and biliary tract,as well as through the blood-brain,placental,and possibly blood-testis *** recognizes and transports numerous anticancer drugs including conventional chemotherapeutic and targeted small therapeutic molecules relatively new in clinical ***,BCRP expression in cancer cells directly causes MDR by active efflux of anticancer *** BCRP is also known to be a stem cell marker,its expression in cancer cells could be a manifestation of metabolic and signaling pathways that confer multiple mechanisms of drug resistance,self-renewal(stemness),and invasiveness(aggressiveness),and thereby impart a poor ***,blocking BCRP-mediated active efflux may provide a therapeutic benefit for *** the precise molecular mechanisms for BCRP gene expression may lead to identification of a novel molecular target to modulate BCRP-mediated *** evidence suggests that BCRP gene transcription is regulated by a number of trans-acting elements including hypoxia inducible factor 1α,estrogen receptor,and peroxisome proliferator-activated ***,alternative promoter usage,demethylation of the BCRP promoter,and histone modification are likely associated with drug-induced BCRP overexpression in cancer ***,PI3K/AKT signaling may play a critical role in modulating BCRP function under a variety of *** biological events seem involved in a complicated *** the events would be an essential first step to developing a method to modulate BCRP function to aid patients with *** review will present a sy

关键词：多重耐药性基因表达调控组蛋白修饰乳腺癌过氧化物酶体增殖物激活受体分子机制多药耐药肿瘤细胞

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Unconformity structures controlling stratigraphic reservoirs in the north-west margin of Junggar basin, North-west China

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Frontiers of Earth Science 2013年第1期7卷 55-64页

作者： Kongyou WU douglas PATON Ming ZHA School of Geoscience China University of Petroleum Qingdao 266555 China School of Earth and Environment University of Leeds Leeds LS2 9JT UK

Tectonic movements formed several unconfor- mities in the north-west margin of the Junggar basin. Based on data of outcrop, core, and samples, the unconformity is a structural body whose formation associates with weath- ering, leaching, and onlap. At the same time, the structural body may be divided into three layers, including upper layer, mid layer, and lower layer. The upper layer with good primary porosity serves as the hydrocarbon migration system, and also accumulates the hydrocarbon. The mid layer with compactness and ductility can play a role as cap rock, the strength of which increases with depth. The lower layer with good secondary porosity due to weathering and leaching can form the stratigraphic truncation traps. A typical stratigraphie reservoir lying in the unconformity between the Jurassic and Triassic in the north-west margin of the Junggar basin was meticulously analyzed in order to reveal the key controlling factors. The results showed that the hydrocarbon distribution in the stratigraphic onlap reservoirs was controlled by the onlap line, the hydro- carbon distribution in the stratigraphic truncation reser- voirs was confined by the truncation line, and the mid layer acted as the key sealing rock. So a conclusion was drawn that ＂two lines （onlap line and truncation line） and a body （unconformity structural body）＂ control the formation and distribution of stratigraphic reservoirs.

关键词： unconformity structural body stratigraphicreservoir key controlling factors Jurassic bottom north-west margin of the Junggar basin

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Interference-enhanced optical magnetism in surface high-index resonators: a pathway toward high-performance ultracompact linear and nonlinear meta-optics

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Photonics Research 2019年第11期7卷 1296-1305页

作者： LEI KANG HUAGUANG BAO douglas H.WERNER Department of Electrical Engineering and Center for Nanoscale Science The Pennsylvania State University

Artificial magnetism in optical frequencies is one of the most intriguing phenomena associated with metamaterials. The Mie resonance of high-index resonators provides an alternative approach to achieving optical magnetism with simple structures. Given the generally moderate refractive index exhibited by available materials at optical frequencies, Mie resonances usually suffer from coupling between the multipole modes, and the corresponding response of the Mie metasurfaces can be analyzed based on the concept of "meta-optics."Here, we show that the optical magnetism in high-index resonators can be significantly enhanced by adding a highly reflective back mirror to the system. To highlight the transformative ability of this approach for improving meta-optics in the linear and nonlinear regimes, two proof-of-concept demonstrations are *** modeling reveals that low-pump power ultrafast nonlinear optics can be realized in periodic Si nanodisk arrays backed with a gold film, a system supporting guided resonance modes. Moreover, based on the enhanced magnetism of individual high-index resonators, a pair of silicon cuboids is demonstrated as a magnetic antenna for directional excitation of surface plasmon waves. The interference-enhanced magnetism of high-index resonators provides a disruptive technology for enabling meta-optics comprising ultracompact, high-speed, and power-efficient photonic devices.

关键词： optical antenna pump

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