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51.
52.
Evaluating computer-aided detection algorithms 总被引:1,自引:0,他引:1
Computer-aided detection (CAD) has been attracting extensive research interest during the last two decades. It is recognized that the full potential of CAD can only be realized by improving the performance and robustness of CAD algorithms and this requires good evaluation methodology that would permit CAD designers to optimize their algorithms. Free-response receiver operating characteristic (FROC) curves are widely used to assess CAD performance, however, evaluation rarely proceeds beyond determination of lesion localization fraction (sensitivity) at an arbitrarily selected value of nonlesion localizations (false marks) per image. This work describes a FROC curve fitting procedure that uses a recent model of visual search that serves as a framework for the free-response task. A maximum likelihood procedure for estimating the parameters of the model from free-response data and fitting CAD generated FROC curves was implemented. Procedures were implemented to estimate two figures of merit and associated statistics such as 95% confidence intervals and goodness of fit. One of the figures of merit does not require the arbitrary specification of an operating point at which to evaluate CAD performance. For comparison a related method termed initial detection and candidate analysis was also implemented that is applicable when all suspicious regions are reported. The two methods were tested on seven mammography CAD data sets and both yielded good to excellent fits. The search model approach has the advantage that it can potentially be applied to radiologist generated free-response data where not all suspicious regions are reported, only the ones that are deemed sufficiently suspicious to warrant clinical follow-up. This work represents the first practical application of the search model to an important evaluation problem in diagnostic radiology. Software based on this work is expected to benefit CAD developers working in diverse areas of medical imaging. 相似文献
53.
Preparation and comparative evaluation of 99mTc‐HYNIC‐cNGR and 99mTc‐HYNIC‐PEG2‐cNGR as tumor‐targeting molecular imaging probes
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Kusum Vats Drishty Satpati Rohit Sharma Chandan Kumar Haladhar Dev Sarma Sharmila Banerjee 《Journal of labelled compounds & radiopharmaceuticals》2018,61(2):68-76
The tripeptide sequence asparagine‐glycine‐arginine (NGR) specifically recognizes aminopeptidase N (APN or CD13) receptors highly expressed on tumor cells and vasculature. Thus, NGR peptides can precisely deliver therapeutic and diagnostic compounds to CD13 expressing cancer sites. In this regard, 2 NGR peptide ligands, HYNIC‐c(NGR) and HYNIC‐PEG2‐c(NGR), were synthesized, radiolabeled with 99mTc, and evaluated in CD13‐positive human fibrosarcoma HT‐1080 tumor xenografts. The radiotracers, 99mTc‐HYNIC‐c(NGR) and 99mTc‐HYNIC‐PEG2‐c(NGR), could be prepared in approximately 95% radiochemical purity and exhibited excellent in vitro and in vivo stability. The radiotracers were hydrophilic in nature with log P values being ?2.33 ± 0.05 and ?2.61 ± 0.08. The uptake of 2 radiotracers 99mTc‐HYNIC‐c(NGR) and 99mTc‐HYNIC‐PEG2‐c(NGR) was similar in nude mice bearing human fibrosarcoma HT‐1080 tumor xenografts, which was significantly reduced (P < .05) during blocking studies. The 2 radiotracers being hydrophilic cleared rapidly from blood, liver, and intestine and were excreted through renal pathway. The pharmacokinetics of 99mTc‐labeled HYNIC peptide could not be modulated through introduction of PEG2 unit, thus posing a challenge for studies with other linkers towards enhanced tumor uptake and retention. 相似文献
54.
Aileen S. Garcia Dipti A. Dev Virginia C. Stage 《Journal of nutrition education and behavior》2018,50(9):905-912
Objective
Determine the predictors of child care providers’ parent engagement regarding child nutrition in child care centers (CCCs) and family child care homes (FCCHs).Design
Cross-sectional.Setting
Child care centers and FCCHs.Participants
Child care center directors (n?=?337) and FCCH providers (n?=?1,153) completed a self-administered survey.Main Outcome Measures
Fifteen variables were examined as predictors for parent engagement: providers’ perceived barriers to communication, participation in Go Nutrition and Physical Self- Assessment in Child Care, National Association for the Education of Young Children accreditation, participation in Quality Ratings and Improvement Systems, feeding practices, and professional development.Analysis
Structural equation modeling examined the relation between variables for CCCs and for FCCHs.Results
For CCCs, NAEYC accreditation, providers’ perceived barriers regarding parents’ cultural beliefs about food, parents not liking the taste of healthy foods, and parents prioritizing other food-related topics over healthy eating significantly predicted parent engagement. For FCCHs, participation in Go Nutrition and Physical Self- Assessment in Child Care, perceiving parents to be busy, not wanting to offend parents, and practicing family-style dining were significantly related to parent engagement. For both CCCs and FCCHs, professional development regarding child nutrition was related to parent engagement.Conclusions and Implications
Focusing professional development on child care contexts and addressing providers’ perceived barriers may improve parent engagement. 相似文献55.
Engaging new refugee in Australian communities at risk for chronic hepatitis B infection into care: A peer‐educator intervention
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Katherine Sievert Paul O'Neill Youlin Koh Jia‐Hui Lee Anouk Dev Suong Le 《Health & social care in the community》2018,26(5):744-750
Chronic Hepatitis B (CHB) infection and subsequent liver complications are rising in prevalence in Australia due to increased migration from endemic regions. Nearly 50% of all those living with CHB in Australia are undiagnosed, leading to missed opportunities for liver cancer and cirrhosis prevention. Health literacy around CHB among refugee communities such as Afghan, Rohingyan, and Sudanese populations (all with a high prevalence of CHB) is low, partly due to a paucity of targeted health promotion programmes; despite the release of the Victorian Hepatitis B Strategy (2016–2020). We developed a peer‐education intervention in these three communities to deliver CHB focused radio programmes and community forums in their own language, following a needs assessment consisting of semistructured interviews and surveys. Effectiveness of this intervention was measured through paired comparison of disease‐knowledge assessment pre and post forum. Community forums were held between 2015 and 2016, with 25 attendees at the Rohingyan forum (68% male), 10 attendees at the Afghan forum (90% male) and 0 attendees at the Sudanese forum. Participants demonstrated a significant improvement in CHB knowledge between pre‐ and post‐forum surveys (p‐value < 0.05). A peer‐educator approach was a cost‐effective health promotion strategy in building CHB knowledge and dispelling misconceptions within the Afghan and Rohingya communities. There were significant barriers in the engagement of the South Sudanese community, which will inform future strategies for health promotion. 相似文献
56.
57.
Himanshu Bhusan Sahoo Dev Das Santani Rakesh Sagar 《Indian journal of pharmacology》2014,46(5):531-537
Aim:
The study was designed to investigate the chemopreventive potential of flavonoidal fractions of Apium leptophyllum fruits (FFALF) on Swiss mice.Materials and Methods:
Skin tumor or papilloma was developed by topical application of DMBA (25 μg in 0.1 ml acetone) on intrascapular region of mice, twice weekly for 8 weeks. The animals were divided into six groups: Group I (vehicle control); group II (FFALF control, 5 mg/kg); group III (carcinogenic control, DMBA treated initially for 8 weeks); and group IV, V and VI as pre-treated group (FFALF 5, 10 and 20 mg/kg respectively for 16 weeks along with DMBA treatment). After the 16th week of treatment; the tumor morphology, skin histopathology, and biochemical and antioxidant biomarkers were measured and compared with carcinogenic control as well as vehicle control.Results:
The co-administration of FFALF with DMBA-treated groups showed significant (P ≤ 0.001) prevention against skin papilloma and normalized the status of lipid peroxidation with antioxidant biomarkers in a dose-dependent manner as compared to carcinogenic control.Conclusions:
Thus, the present study suggests that the FFALF is non-carcinogenic and has chemopreventive potential on DMBA-induced carcinogenesis in mouse, which may be due to the modulation of cutaneous lipid peroxidation or enhancement of total antioxidant capacity.KEY WORDS: Apium leptophyllum, antioxidant biomarker, chemoprevention, DMBA, skin papilloma 相似文献58.
Leukotrienes, generated from arachidonic acid via the lipoxygenase pathway, play an important role in the pathophysiology of asthma. Therefore, leukotriene inhibitors, such as Zileuton, are used in the treatment of asthma. However, thromboxanes, generated from arachidonic acid via the cyclooxygenase pathway, play an important role in platelet aggregation and thrombosis. Therefore, we studied whether Zileuton, by shifting arachidonic acid to the cyclooxygenase pathway, enhances thromboxane production and, hence, platelet aggregation. Blood samples were collected from 10 asthmatic patients before and 2 weeks after standard Zileuton treatment. Spontaneous platelet aggregation was measured in platelet-rich plasma. Platelet-rich plasma was also used to determine thromboxane B(2), a stable metabolite of thromboxane A(2), as the indirect measure of thromboxane A(2) because thromboxane A(2) is too unstable for assay. Baseline thromboxane B(2) and platelet aggregation values in the 10 asthmatic patients were normal. Treatment with Zileuton for 2 weeks significantly increased thromboxane B(2) levels from baseline levels of 267 +/- 54 microg/l to 389 +/- 62 microg/l after 2 weeks of treatment (P < 0.0002). Spontaneous platelet aggregation also increased significantly from baseline values of 4.2 +/- 2.4% to 6.8 +/- 2.8% after 2 weeks of treatment (P < 0.0001). These results establish that Zileuton, an effective drug for asthma, adversely affects in vitro platelet function. The findings suggest that this drug, and perhaps related agents also, may pose a thrombotic risk; clinical attention will be needed to address this possibility. 相似文献
59.
I K Dev B B Yates J Leong W S Dallas 《Proceedings of the National Academy of Sciences of the United States of America》1988,85(5):1472-1476
Analysis of mutant Escherichia coli thymidylate synthases (EC 2.1.1.45) with various amino acids substituted for cysteine at position 146 revealed the cysteine to be involved in the binding of 2'-deoxyuridylate as well as initiating the catalytic process. The substitution of a serine or alanine residue at position 146 did not appreciably alter the binding affinity for 2'-deoxyuridylate but the serine mutant enzyme was less active by a factor of 5000, whereas the alanine mutant enzyme was catalytically inactive. In contrast, the substitution of a glycine or threonine at position 146 created inactive enzymes with higher 2'-deoxyuridylate dissociation constants. The dissociation constant values for 2'-deoxyuridylate were used to estimate the overall contribution of the side chain of the amino acid at position 146 to substrate binding. The results suggested that the side chains of cysteine, alanine, and serine make nonspecific but effective van der Waals contacts with 2'-deoxyuridylate, thereby contributing about 0.82 kcal.mol-1 (1 cal = 4.184 J) to the apparent binding energy of the substrate. 相似文献
60.
Sharmistha Dev MD MPH Andrew A. Gonzalez MD JD MPH Jessica Coffing MPH James E. Slaven MS Shantanu Dev BS Stan Taylor MA Carrie Ballard S. Nicole Hastings MD MHSc Dawn M. Bravata MD 《Academic emergency medicine》2023,30(4):349-358