720 Hits in 1.6 sec

Fair Matching in Dynamic Kidney Exchange [article]

Irena Gao
2019 arXiv   pre-print
Kidney transplants are sharply overdemanded in the United States. A recent innovation to address organ shortages is a kidney exchange, in which willing but medically incompatible patient-donor pairs swap donors so that two successful transplants occur. Proposed rules for matching such pairs include static fair matching rules, which improve matching for a particular group, such as highly-sensitized patients. However, in dynamic environments, it seems intuitively fair to prioritize time-critical
more » ... airs. We consider the tradeoff between established sensitization fairness and time fairness in dynamic environments. We design two algorithms, SENS and TIME, and study their patient loss. We show that the there is a theoretical advantage to prioritizing time-critical patients (around 9.18% tradeoff on U.S. data) rather than sensitized patients. Our results suggest that time fairness needs to be considered in kidney exchange. We then propose a batching algorithm for current branch-and-price solvers that balances both fairness needs.
arXiv:1912.10563v1 fatcat:dt6bp6bxrbdajmsxp5dk6a52b4

Healthy Access for Healthy Places: A Multidimensional Food Access Measure [article]

Irena Gao, Marynia Kolak
2019 arXiv   pre-print
When it comes to preventive healthcare, place matters. It is increasingly clear that social factors, particularly reliable access to healthy food, are as determinant to health and health equity as medical care. However, food access studies often only present one-dimensional measurements of access. We hypothesize that food access is a multidimensional concept and evaluated Penchansky and Thomas's 1981 definition of access. In our approach, we identify ten variables contributing to food access in
more » ... the City of Chicago and use principal component analysis to identify vulnerable populations with low access. Our results indicate that within the urban environment of the case study site, affordability is the most important factor in low food accessibility, followed by urban youth, reduced mobility, and higher immigrant population.
arXiv:1912.11351v1 fatcat:rr5jzyihnjatxlklvdx7aetomi

Topological Interface-State Lasing in a Polymer-Cholesteric Liquid Crystal Superlattice [article]

Yu Wang, Donghao Yang, Shaohua Gao, Xinzheng Zhang, Irena Drevensek-Olenik, Qiang Wu, Marouen Chemingui, Zhigang Chen, Jingjun Xu
2022 arXiv   pre-print
The advance of topological photonics has heralded a revolution for manipulating light as well as for the development of novel photonic devices such as topological insulator lasers. Here, we demonstrate topological lasing of circular polarization in a polymer-cholesteric liquid crystal (P-CLC) superlattice, tunable in the visible wavelength regime. By use of the femtosecond-laser direct-writing and self-assembling techniques, we establish the P-CLC superlattice with a controlled mini-band
more » ... re and a topological interface defect, thereby achieving a low threshold for robust topological lasing at about 0.4 uJ. Thanks to the chiral liquid crystal, not only the emission wavelength is thermally tuned, but the circularly polarized lasing is readily achieved. Our results bring about the possibility to realize compact and integrated topological photonic devices at low cost, as well as to engineer an ideal platform for exploring topological physics that involves light-matter interaction in soft-matter environments.
arXiv:2205.06536v1 fatcat:fsuw5yqa4zh7diig6k27tvvtby

Monte Carlo modeling of X-valley leakage in quantum cascade lasers

Xujiao Gao, Dan Botez, Irena Knezevic
2007 Journal of Computational Electronics  
This paper presents the first comprehensive Monte Carlo simulation of GaAs/AlGaAs quantum cascade lasers (QCLs) that takes both -and X-valley transport into account and investigates the effect of X-valley leakage on the QCL performance. Excellent agreement with experimental data is obtained for the GaAs/Al 0.45 Ga 0.55 As QCL at cryogenic and room temperatures. The model reveals two carrier-loss mechanisms into the X valley: coupling of the continuumlike states with the X states in the same
more » ... e, and coupling between the localized states in the simulated stage with the X states in the next stage. Simulation results demonstrate that the 45% Al QCL has small X-valley leakage at both 77 K and 300 K, due to the very good confinement of the states, stemming from the high Al content.
doi:10.1007/s10825-006-0117-3 fatcat:7xdbuqlbknbp5i5ghldhwejh6u

Network of Interdependent Networks: Overview of Theory and Applications [chapter]

Dror Y. Kenett, Jianxi Gao, Xuqing Huang, Shuai Shao, Irena Vodenska, Sergey V. Buldyrev, Gerald Paul, H. Eugene Stanley, Shlomo Havlin
2014 Understanding Complex Systems  
Complex networks appear in almost every aspect of science and tech-1 nology. Previous work in network theory has focused primarily on analyzing single 2 networks that do not interact with other networks, despite the fact that many real-3 world networks interact with and depend on each other. Very recently an analytical 4 introduced. Here we review the analytical framework and the results for percola-6 tion laws for a network of networks (NON) formed by n interdependent random 7 networks. The
more » ... colation properties of a network of networks differ greatly from 8 those of single isolated networks. In particular, although networks with broad degree 9 distributions, e.g., scale-free networks, are robust when analyzed as single networks, 10 they become vulnerable in a NON. Moreover, because the constituent networks of 11 a NON are connected by node dependencies, a NON is subject to cascading failure. 12 When there is strong interdependent coupling between networks, the percolation 13 transition is discontinuous (is a first-order transition), unlike the well-known con-14 tinuous second-order transition in single isolated networks. We also review some 15 possible real-world applications of NON theory. AQ1 16 1.1 Introduction 17 The interdisciplinary field of network science has attracted great attention in recent 18 years [1-25]. This has taken place because an enormous amount of data regarding 19 social, economic, engineering, and biological systems has become available over 20 the past two decades as a result of the information and communication revolution 21 brought about by the rapid increase in computing power. The investigation and grow-22 ing understanding of this extraordinary amount of data will enable us to make the 23 infrastructures we use in everyday life more efficient and more robust. The original 24 model of networks, random graph theory, developed in the 1960s by Erdős and Rényi 25 (ER), is based on the assumption that every pair of nodes is randomly connected with 26 the same probability (leading to a Poisson degree distribution). In parallel, lattice net-27 works in which each node has the same number of links have been used in physics 28 to model physical systems. While graph theory was a well-established tool in the 29 mathematics and computer science literature, it could not adequately describe mod-30 ern, real-world networks. Indeed, the pioneering observation by Barabási in 1999 31 [2], that many real networks do not follow the ER model but that organizational 32 principles naturally arise in most systems, led to an overwhelming accumulation of 33 supporting data, new models, and novel computational and analytical results, and 34 led to the emergence of a new science: complex networks. 35 Significant advances in understanding the structure and function of networks, 36 and mathematical models of networks have been achieved in the past few years. 37 These are now widely used to describe a broad range of complex systems, from 38 techno-social systems to interactions amongst proteins. A large number of new mea-39 sures and methods have been developed to characterize network properties, includ-40 ing measures of node clustering, network modularity, correlation between degrees 41 of neighboring nodes, measures of node importance, and methods for the identifi-42 cation and extraction of community structures. These measures demonstrated that 43 many real networks, and in particular biological networks, contain network motifs-44 small specific subnetworks-that occur repeatedly and provide information about 45 312219_1_En_1_Chapter TYPESET DISK LE CP Disp.:23/11/2013 Pages: 36 Layout: T1-Standard U N C O R R E C T E D P R O O F 1 Network of Interdependent Networks 5 functionality [8]. Dynamical processes, such as flow and electrical transport in het-46 erogeneous networks, were shown to be significantly more efficient compared to ER 47 networks [26, 27]. 48 Complex networks are usually non-homogeneous structures that exhibit a power-49 law form in their degree (number of links per node) distribution. These systems 50 are called scale-free networks. Some examples of real-world scale-free networks 51 include the Internet [3], the WWW [4], social networks representing the relations 52 between individuals, infrastructure networks such as airlines [28, 29], networks in 53 biology, in particular networks of protein-protein interactions [30], gene regulation, 54 and biochemical pathways, and networks in physics, such as polymer networks or 55 the potential energy landscape network. The discovery of scale-free networks has led 56 to a re-evaluation of the basic properties of networks, such as their robustness, which 57 exhibit a character that differs drastically from that of ER networks. For example, 58 while homogeneous ER networks are vulnerable to random failures, heterogeneous 59 scale-free networks are extremely robust [4, 5]. Much of our current knowledge of 60 networks is based on ideas borrowed from statistical physics, e.g., percolation theory, 61 fractal analysis, and scaling analysis. An important property of these infrastructures is 62 their stability, and it is thus important that we understand and quantify their robustness 63 in terms of node and link functionality. Percolation theory was introduced to study 64 network stability and to predict the critical percolation threshold [5]. The robustness 65 of a network is usually (i) characterized by the value of the critical threshold analyzed 66 using percolation theory [31] or (ii) defined as the integrated size of the largest 67 connected cluster during the entire attack process [32]. The percolation approach 68 was also extremely useful in addressing other scenarios, such as efficient attacks 69 or immunization [6, 7, 14, 33, 34], for obtaining optimal path [35] as well as for 70 designing robust networks [32]. Network concepts were also useful in the analysis 71 and understanding of the spread of epidemics [36, 37], and the organizational laws 72 of social interactions, such as friendships [38, 39] or scientific collaborations [40]. 73 Moreira et al. investigated topologically-biased failure in scale-free networks and 74 controlled the robustness or fragility by fine-tuning the topological bias during the 75 failure process [41]. 76 Because current methods deal almost exclusively with individual networks treated 77 as isolated systems, many challenges remain [42]. In most real-world systems an indi-78 vidual network is one component within a much larger complex multi-level network 79 (is part of a network of networks). As technology has advanced, coupling between 80 networks has become increasingly strong. Node failures in one network will cause 81 the failure of dependent nodes in other networks, and vice-versa [43]. This recursive 82 process can lead to a cascade of failures throughout the network of networks system. 83 The study of individual particles has enabled physicists to understand the properties 84 of a gas, but in order to understand and describe a liquid or a solid the interactions 85 between the particles also need to be understood. So also in network theory, the study 86 of isolated single networks brings extremely limited results-real-world noninter-87 acting systems are extremely rare in both classical physics and network study. Most 88 real-world network systems continuously interact with other networks, especially 89 since modern technology has accelerated network interdependency. 90 312219_1_En_1_Chapter TYPESET DISK LE CP Disp.:23/11/2013 Pages: 36 Layout: T1-Standard U N C O R R E C T E D P R O O F 6 D . Y . K e n e t t e t a l . 112 To study the robustness of interdependent networks systems, we begin by remov-113 ing a fraction 1 − p of network A nodes and all the A-edges connected to these 114 nodes. As an outcome, all the nodes in network B that are connected to the removed 115 A-nodes by A → B links are also removed since they depend on the removed nodes 116 in network A. Their B edges are also removed. Further, the removed B nodes will 117 cause the removal of additional nodes in network A which are connected to the re-118 moved B-nodes by B → A links. As a result, a cascade of failures that eliminates 119 virtually all nodes in both networks can occur. As nodes and edges are removed, each 120 312219_1_En_1_Chapter TYPESET DISK LE CP Disp.:23/11/2013 Pages: 36 Layout: T1-Standard U N C O R R E C T E D P R O O F 1 Network of Interdependent Networks 7 network breaks up into connected components (clusters). The clusters in network A 121 (connected by A-edges) and the clusters in network B (connected by B-edges) are 122 different since the networks are each connected differently. If one assumes that small 123 clusters (whose size is below certain threshold) become non-functional, this may 124 invoke a recursive process of failures that we now formally describe. 125 Our insight based on percolation theory is that when the network is fragmented the 126 nodes belonging to the giant component connecting a finite fraction of the network 127 are still functional, but the nodes that are part of the remaining small clusters become 128 non-functional. Thus in interdependent networks only the giant mutually-connected 129 cluster is of interest. Unlike clusters in regular percolation whose size distribution 130 is a power law with a p-dependent cutoff, at the final stage of the cascading failure 131 process just described only a large number of small mutual clusters and one giant 132 mutual cluster are evident. This is the case because the probability that two nodes that 133 are connected by an A-link and their corresponding two nodes are also connected 134 by a B-link scales as 1/N B , where N B is the number of nodes in network B. So 135 the centrality of the giant mutually-connected cluster emerges naturally and the 136 mutual giant component plays a prominent role in the functioning of interdependent 137 networks. When it exists, the networks preserve their functionality, and when it does 138 not exist, the networks split into fragments so small they cannot function on their 139 own. 140 We ask three questions: What is the critical p = p c below which the size of any 141 mutual cluster constitutes an infinitesimal fraction of the network, i.e., no mutual 142 giant component can exist? What is the fraction of nodes P ∞ ( p) in the mutual giant 143 component at a given p? How do the cascade failures at each step damage the giant 144 functional component? 145 Note that the problem of interacting networks is complex and may be strongly 146 affected by variants in the model, in particular by how networks and dependency 147 links are characterized. In the following section we describe several of these model 148 variants. 149 1.3 Theory of Interdependent Networks 150 In order to better understand how present-day crucially-important infrastructures 151 interact, Buldyrev et al. [43] recently developed a mathematical framework to study 152 percolation in a system of two coupled interdependent networks subject to cascading 153 failure. Their analytical framework is based on a generating function formalism 154 widely used in studies of single-network percolation and single-network structure 155 [40, 43, 45]. Using the framework to study interdependent networks, we can follow 156 the dynamics of the cascading failures as well as derive analytic solutions for the 157 final steady state. Buldyrev et al. [43] found that interdependent networks were 158 significantly more vulnerable than their noninteracting counterparts. The failure of 159 even a small number of elements within a single network in a system may trigger a 160 catastrophic cascade of events that propagates across the global connectivity. For a 161 312219_1_En_1_Chapter TYPESET DISK LE CP Disp.:23/11/2013 Pages: 36 Layout: T1-Standard 209 210
doi:10.1007/978-3-319-03518-5_1 fatcat:3fy4letddnbzdki25p3dmj65ya

Coupling of Defect Modes in Cholesteric Liquid Crystals Separated by Isotropic Polymeric Layers

Shaohua Gao, Yanzi Zhai, Xinzheng Zhang, Xiao Song, Jiayi Wang, Irena Drevensek-Olenik, Romano Rupp, Jingjun Xu
2018 Polymers  
Cholesteric liquid crystal structures with multiple isotropic defect layers exhibit localized optical modes (defect modes). Coupling effects between these modes were simulated using the finite difference time domain method. Analogous to the well-known result of the tight-binding approximation in solid state physics, splitting of the defect modes takes place, as soon as the structure contains more than one defect layer. The dispersion relation of the mini-bands forming within the photonic band
more » ... p of the structure is calculated numerically. The structures might have promising applications for multiwavelength filters and low-threshold lasers.
doi:10.3390/polym10070805 pmid:30960730 pmcid:PMC6403987 fatcat:yz575t6mlrgkna7zmwwh6boovy

Transcriptional repression of K-Rta by Kaposi's sarcoma-associated herpesvirus K-bZIP is not required for oriLyt-dependent DNA replication

Cyprian Rossetto, Yang Gao, Irena Yamboliev, Iva Papousková, Gregory Pari
2007 Virology  
Kaposi's sarcoma-associated herpesvirus origin-dependent DNA replication requires the core replication proteins plus K-Rta and K-bZIP. To determine which K-bZIP protein domains contribute to oriLyt-dependent DNA replication and facilitate suppression of K-Rta-mediated transcriptional activation, we generated a series of deletion constructs and site-directed mutations within the K-bZIP ORF. Mutation of key leucine residues within the putative leucine zipper (LZ) motif eliminated the ability of
more » ... e protein to homodimerize and complement oriLyt-dependent DNA replication. Deletion of the basic amino acid region (BR) or LZ domain did not affect the ability of K-bZIP to bind to K-Rta indicating that either region contributes to heterodimerization with K-Rta. However, deletions or mutations introduced into both the LZ and BR resulted in elimination of the suppressive activity of K-bZIP even in the presence of a K-bZIP-K-Rta interaction. Interestingly, mutants that lacked the ability to suppress K-Rta transactivation were still capable of complementing oriLyt-dependent DNA replication, indicating that this activity does not contribute to the DNA synthesis-related activity of K-bZIP.
doi:10.1016/j.virol.2007.08.019 pmid:17889220 pmcid:PMC2134788 fatcat:jo7f5mzhtbdorbfgzzbqpvq2ui

Role of bradykinin B1 and B2 receptors in normal blood pressure regulation

Arvi Duka, Irena Duka, Guohong Gao, Sherene Shenouda, Irene Gavras, Haralambos Gavras
2006 American Journal of Physiology. Endocrinology and Metabolism  
With inhibition or absence of the bradykinin B 2 receptor (B2R), B1R is upregulated and assumes some of the hemodynamic properties of B 2R, indicating that both participate in the maintenance of normal vasoregulation or to development of hypertension. Herein we further evaluate the role of bradykinin in normal blood pressure (BP) regulation and its relationship with other vasoactive factors by selectively blocking its receptors. Six groups of Wistar rats were treated for 3 wk: one control group
more » ... with vehicle alone, one with concurrent administration of B 1R antagonist R-954 (70 g ⅐ kg Ϫ1 ⅐ day Ϫ1 ) and B2R antagonist HOE-140 (500 g ⅐ kg Ϫ1 ⅐ day Ϫ1 ), one with R-954 alone, one with HOE 140 alone, one with concurrent administration of both R-954 and HOE-140 plus the angiotensin antagonist losartan (5 mg ⅐ kg Ϫ1 ⅐ day Ϫ1 ), and one with only losartan. BP was measured continuously by radiotelemetry. Only combined administration of B 1R and B2R antagonists produced a significant BP increase from a baseline of 107-119 mmHg at end point, which could be partly prevented by losartan and was not associated with change in catecholamines, suggesting no involvement of the sympathoadrenal system. The impact of blockade of bradykinin on other vasoregulating systems was assessed by evaluating gene expression of different vasoactive factors. There was upregulation of the eNOS, AT1 receptor, PGE2 receptor, and tissue kallikrein genes in cardiac and renal tissues, more pronounced when both bradykinin receptors were blocked; significant downregulation of AT 2 receptor gene in renal tissues only; and no consistent changes in B 1R and B2R genes in either tissue. The results indicate that both B 1R and B2R contribute to the maintenance of normal BP, but one can compensate for inhibition of the other, and the chronic inhibition of both leads to significant upregulation in the genes of related vasoactive systems. bradykinin inhibition; angiotensin II; vasoactive factors; gene expression
doi:10.1152/ajpendo.00382.2005 pmid:16507603 fatcat:5nlnrbivwjab3fpatxqarfjhfm

Design and optimization of a GaAs-based sub-7-μm quantum cascade laser based on multivalley Monte Carlo simulation

Xujiao Gao, Mithun D'Souza, Dan Botez, Irena Knezevic
2008 Optical and quantum electronics  
It was shown(Gao et al. 2006 (Gao et al. , 2007a that the X-valley leakage 56 occurs due to the strong coupling between the Ŵ-continuum (Ŵ c ) states (levels 4 and 5 in 57Fig. 1) and the X-states in the  ...  Fig. 1 1 Monte Carlo simulator (Gao et al. 2006, 2007a) that we have recently devel-44 oped is a suitable approach for transport simulation of mid-IR QCLs.  ... 
doi:10.1007/s11082-008-9221-x fatcat:6bj3pytkhrco3hs7dqhs5w5nr4

Erythrocyte fatty acids and breast cancer risk: a case-control study in Shanghai, China

Jackilen Shannon, Irena B King, Rachel Moshofsky, Johanna W Lampe, Dao Li Gao, Roberta M Ray, David B Thomas
2007 American Journal of Clinical Nutrition  
The role of individual fatty acids in the development and progression of breast cancer is unclear. Although in vitro and animal experiments have supported an inverse association between intake of long chain nҀ3 fatty acids [primarily eicosapentaenoic acid (EPA) and docosahexaenoic acid] and breast cancer risk, findings from population studies are inconsistent. Recent studies have also shown associations between the ratio of saturated to monounsaturated fatty acids (SI) and breast cancer risk.
more » ... e SI reflects the activity of several genes involved in lipid metabolism, including fatty acid synthase and steroyl coenzyme-A desaturase, that have been shown to be overexpressed in breast cancer. Objective: The purpose of this analysis was to determine the association between erythrocyte fatty acid concentrations and breast cancer risk among women participating in a randomized trial of breast self-examination in Shanghai, China. Design: We conducted a case-control study. Erythrocyte fatty acid concentrations were determined in specimens from 322 women with histologically confirmed breast cancer and 1030 frequency agematched control women. Results: We report a significant direct association among palmitic, ␥-linolenic, palmitoleic, and vaccenic acids and risk of breast cancer. Total nҀ3 fatty acids, EPA, and the SI for palmitic to palmitoleic acid were associated with significantly lower risk of breast cancer. Conclusion: Our results support a protective effect of nҀ3 fatty acids on breast cancer risk and provide additional evidence for the importance of evaluating the ratio of fatty acids when evaluating diet and breast cancer risk. Am J Clin Nutr 2007;85:1090 -7.
doi:10.1093/ajcn/85.4.1090 pmid:17413110 fatcat:n6nymgyf7zcsff2ntakospiebq

Fruit and vegetable intakes in relation to plasma nutrient concentrations in women in Shanghai, China

Cara L Frankenfeld, Johanna W Lampe, Jackilen Shannon, Dao L Gao, Wenjin Li, Roberta M Ray, Chu Chen, Irena B King, David B Thomas
2011 Public Health Nutrition  
Objective: To evaluate the validity of fruit and vegetable intakes as it relates to plasma carotenoid and vitamin C concentrations in Chinese women, using three classification schemes. Design: Intakes were calculated using an interviewer-administered FFQ. Fruits and vegetables, botanical groups and high-nutrient groups were evaluated. These three classification schemes were compared with plasma carotenoid and vitamin C concentrations from blood samples collected within 1 week of questionnaire
more » ... mpletion. Setting: Shanghai, China. Subjects: Participants (n 2031) comprised women who had participated in a casecontrol study of diet and breast-related diseases nested within a randomized trial of breast self-examination among textile workers (n 266 064) Results: Fruit intake was significantly (P , 0?05) and positively associated with plasma concentrations of a-tocopherol, b-cryptoxanthin, lycopene, a-carotene, b-carotene, retinyl palmitate and vitamin C. Fruit intake was inversely associated with g-tocopherol and lutein 1 zeaxanthin concentrations. Vegetable consumption was significantly and positively associated with g-tocopherol and b-cryptoxanthin concentrations. Each botanical and high-nutrient group was also significantly associated with particular plasma nutrient concentrations. Fruit and vegetable intakes and most plasma nutrient concentrations were significantly associated with season of interview. Conclusions: These results suggest that the manner in which fruits and vegetables are grouped leads to different plasma nutrient exposure information, which may be an important consideration when testing and generating hypotheses regarding disease risk in relation to diet. Interview season should be considered when evaluating the associations of reported intake and plasma nutrients with disease outcomes.
doi:10.1017/s1368980011001029 pmid:21729475 pmcid:PMC3449037 fatcat:c7fdmvjnunh7lj6vay3gyae5ky

Extending the WILDS Benchmark for Unsupervised Adaptation [article]

Shiori Sagawa, Pang Wei Koh, Tony Lee, Irena Gao, Sang Michael Xie, Kendrick Shen, Ananya Kumar, Weihua Hu, Michihiro Yasunaga, Henrik Marklund, Sara Beery, Etienne David (+8 others)
2022 arXiv   pre-print
Tony Lee, Irena Gao, Sang Michael Xie, Kendrick Shen, Ananya Kumar, and Michihiro Yasunaga designed the evaluation framework and implemented the algorithms.  ...  In Advances in Neural Information Processing Systems (NeurIPS), pages 7059-7069, 2019. • Camelyon17-wilds: Tony Lee • CivilComments-wilds: Irena Gao • FMoW-wilds: Sang Michael Xie • iWildCam2020-wilds:  ... 
arXiv:2112.05090v2 fatcat:77b2lkj7yvemteazktwxp4lnda

Material characterisation of a painted beehive panel by advanced spectroscopic and chromatographic techniques in combination with hyperspectral imaging

Klara Retko, Maša Kavčič, Lea Legan, Polonca Ropret, Bojana Rogelj Škafar, Yingwang Gao, John Gilchrist, Matija Strlič, Irena Kralj Cigić
2020 Heritage Science  
AbstractIn this study, a painted beehive panel from the collection of the Slovene Ethnographic Museum was examined with respect to its material composition with the aim to reveal the painting technique. Due to the state of degradation due to outdoor weathering (UV irradiation, rainfall, extreme temperature and humidity fluctuations), as well as past conservation interventions, the object represented a complex analytical challenge. We aimed for non-invasive techniques (FTIR in reflection mode,
more » ... man spectroscopy and hyperspectral imaging in the range of 400–2500 nm); however, in order to explore paint layers, cross-sections were also analysed using Raman spectroscopy. FTIR spectroscopy in transmission mode and gas chromatography coupled to mass spectrometry were also used on sample fragments. Various original materials were identified such as pigments and binders. The surface coating applied during conservation interventions was also characterised. Additionally, organic compounds were found (oxalate, carboxylate), representing transformation products. The potential use of Prussian blue as a background paint layer is discussed.
doi:10.1186/s40494-020-00468-y fatcat:zv27rbt7ejcb3exoh5a5g3ggci

Erythrocyte fatty acids and risk of proliferative and nonproliferative fibrocystic disease in women in Shanghai, China

Jackilen Shannon, Irena B King, Johanna W Lampe, Dao Li Gao, Roberta M Ray, Ming-Gang Lin, Helge Stalsberg, David B Thomas
2008 American Journal of Clinical Nutrition  
Although benign breast changes are more common than breast cancer, little evidence regarding risk factors for benign breast conditions is available. Omega-3 (n-3) fatty acids have antiinflammatory and antiproliferative actions and may be important in reducing the risk of benign conditions. There is a lack of research on the association of n-3 fatty acids with risk of benign fibrocystic breast changes. Objectives: The objectives of the study were to evaluate the role of n-3 and other fatty acids
more » ... in the development of benign proliferative fibrocystic conditions (PFCs) and nonproliferative fibrocystic conditions (NPFCs) in the breast and to evaluate the progression of fibrocystic changes in breast cancer. Design: We conducted a case-control study to determine erythrocyte fatty acid concentrations in 155 women with NPFCs, 185 women with PFCs, 241 women with breast cancer (127 with nonproliferative and 114 with proliferative changes in the noncancerous extratumoral mammary epithelium), and 1030 control subjects. We estimated the relative risk of NPFCs, PFCs, and breast cancer with proliferative and nonproliferative changes in extratumoral tissue compared with the risk of these changes alone. Results: Women in the highest quartile of eicosapentaenoic acid concentrations were 67% less likely to have an NPFC alone or with breast cancer and 49% less likely to have breast cancer than were women with PFCs. c-Linolenic acid (18:3n-6) was positively associated with all fibrocystic and cancerous conditions. Palmitic: palmitoleic acid (n-7 saturation index) was inversely associated with risk in all comparisons. Conclusion: Our results support a protective effects of n-3 fatty acid intake and the n-7 saturation index against benign fibrocystic breast changes and the progression of proliferative changes to breast cancer. Am J Clin Nutr 2009;89:265-76.
doi:10.3945/ajcn.2008.26077 pmid:19056601 pmcid:PMC2647713 fatcat:pk4txo6suzbd7etysyqqyl52fe

Biomarkers of Dietary Exposure Are Associated with Lower Risk of Breast Fibroadenomas in Chinese Women

S. Coosje Dijkstra, Johanna W. Lampe, Roberta M. Ray, Rose Brown, Chunyuan Wu, Wenjin Li, Chu Chen, Irena B. King, Daoli Gao, Yongwei Hu, Jackilen Shannon, Kristiina Wähälä (+1 others)
2010 Journal of Nutrition  
Gao, W. Li, R. Ray, C. Chen, I. King, D. Thomas, unpublished data).  ... 
doi:10.3945/jn.109.119727 pmid:20484550 pmcid:PMC2884331 fatcat:dz7ms7qpyratvif7icrvwud3a4
« Previous Showing results 1 — 15 out of 720 results