Browsing by Author "Zhao, Y"

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Open Access
A Glimpse Into Duke Research: Where Are You Now?
(2017-02-28) Yuan, A; Feng, L; Qin, X; Zhao, Y
Duke is one of the leading sites for research across the nation, throughout the world where professionals are defining the way to a better and healthier future. A thorough understanding of how Duke networks behave is crucial to their efficient operation. By visualizing data on networks, it is possible to greatly improve our knowledge of how Duke researchers collaborate and detect patterns that would not be evident in a database alone. Our focus is on mapping collaboration networks. Clusters of nodes in the maps show both the research communities that coalesce from different departments or affiliations and the relationship among those communities. The maps also show the collaborations that have not been made, which indicate opportunities for future research. The goal of this visualization was to examine the geographic spread of collaborations represented in the scholars@duke dataset. The goal of the Scholars@Duke Visualization Challenge was to create visualizations that capture the richness and dynamism of Duke research. The datasets were provided by Scholars@Duke (https://schoalrs.duke.edu/) and they describe publications, authorships, and scholarly collaborations from university researchers over the past 5 years.
Open Access
Distinct routes to metastasis: plasticity-dependent and plasticity-independent pathways.
(Oncogene, 2016-08-18) Somarelli, JA; Schaeffer, D; Marengo, MS; Bepler, T; Rouse, D; Ware, KE; Hish, AJ; Zhao, Y; Buckley, AF; Epstein, JI; Armstrong, AJ; Virshup, DM; Garcia-Blanco, MA
The cascade that culminates in macrometastases is thought to be mediated by phenotypic plasticity, including epithelial-mesenchymal and mesenchymal-epithelial transitions (EMT and MET). Although there is substantial support for the role of EMT in driving cancer cell invasion and dissemination, much less is known about the importance of MET in the later steps of metastatic colonization. We created novel reporters, which integrate transcriptional and post-transcriptional regulation, to test whether MET is required for metastasis in multiple in vivo cancer models. In a model of carcinosarcoma, metastasis occurred via an MET-dependent pathway; however, in two prostate carcinoma models, metastatic colonization was MET independent. Our results provide evidence for both MET-dependent and MET-independent metastatic pathways.
Open Access
No-Holdback allocation rules for continuous-time assemble-to-order systems
(Operations Research, 2010-05-01) Lu, Y; Song, JS; Zhao, Y
This paper analyzes a class of common-component allocation rules, termed no-holdback (NHB) rules, in continuous-review assemble-to-order (ATO) systems with positive lead times. The inventory of each component is replenished following an independent base-stock policy. In contrast to the usually assumed first-come-first-served (FCFS) component allocation rule in the literature, an NHB rule allocates a component to a product demand only if it will yield immediate fulfillment of that demand. We identify metrics as well as cost and product structures under which NHB rules outperform all other component allocation rules. For systems with certain product structures, we obtain key performance expressions and compare them to those under FCFS. For general product structures, we present performance bounds and approximations. Finally, we discuss the applicability of these results to more general ATO systems. © 2010 INFORMS.
Open Access
Packings of 3D stars: stability and structure
(Granular Matter, 2016-05-01) Zhao, Y; Liu, K; Zheng, M; Barés, J; Dierichs, K; Menges, A; Behringer, RP
© 2016, Springer-Verlag Berlin Heidelberg.We describe a series of experiments involving the creation of cylindrical packings of star-shaped particles, and an exploration of the stability of these packings. The stars cover a broad range of arm sizes and frictional properties. We carried out three different kinds of experiments, all of which involve columns that are prepared by raining star particles one-by-one into hollow cylinders. As an additional part of the protocol, we sometimes vibrated the column before removing the confining cylinder. We rate stability in terms of r, the ratio of the mass of particles that fall off a pile when it collapsed, to the total particle mass. The first experiment involved the intrinsic stability of the column when the confining cylinder was removed. The second kind of experiment involved adding a uniform load to the top of the column, and then determining the collapse properties. A third experiment involved testing stability to tipping of the piles. We find a stability diagram relating the pile height, h, versus pile diameter, (Formula presented.) , where the stable and unstable regimes are separated by a boundary that is roughly a power-law in h versus (Formula presented.) with an exponent that is less than unity. Increasing vibration and friction, particularly the latter, both tend to stabilize piles, while increasing particle size can destabilize the system under certain conditions.
Open Access
Results of the chronic heart failure intervention to improve medication adherence study: A randomized intervention in high-risk patients
(American Heart Journal, 2015-04-01) Granger, BB; Ekman, I; Hernandez, AF; Sawyer, T; Bowers, MT; Dewald, TA; Zhao, Y; Levy, J; Bosworth, HB
Background Poor adherence to evidence-based medications in heart failure (HF) is a major cause of avoidable hospitalizations, disability, and death. To test the feasibility of improving medication adherence, we performed a randomized proof-of-concept study of a self-management intervention in high-risk patients with HF. Methods Patients with HF who screened positively for poor adherence (<6 Morisky Medication Adherence Scale 8-item) were randomized to either the intervention or attention control group. In the intervention group (n = 44), a nurse conducted self-management training before discharge that focused on identification of medication goals, facilitation of medication-symptom associations, and use of a symptom response plan. The attention control group (n = 42) received usual care; both groups received follow-up calls at 1 week. However, the content of follow-up calls for the attention control group was unrelated to HF medications or symptoms. General linear mixed models were used to evaluate the magnitude of change in adherence and symptom-related events at 3-, 6-, and 12-month follow-up clinic visits. Efficacy was measured as improved medication adherence using nurse-assessed pill counts at each time point. Results Pooled over all time points, patients in the intervention group were more likely to be adherent to medications compared with patients in the attention control group (odds ratio 3.92, t = 3.51, P =.0007). Conclusions A nurse-delivered, self-care intervention improved medication adherence in patients with advanced HF. Further work is needed to examine whether this intervention can be sustained to improve clinical outcomes.