1,460 research outputs found
Identifications of polyphenols and quantification of anthocyanidins in grapes and grape-derived products
No full textPolyphenols in grapes and grape-derived products have attracted public and scientific attention due to their numerous protective roles to human health. A rapid and comprehensive qualitative method was developed to characterize the different classes of polyphenols, such as anthocyanins, flavonols, phenolic acids and flavanols/proanthocyanidins, in grapes and grape-derived products. The detection was achieved by two runs with same HPLC gradient in different MS ionization modes and mobile phase modifiers (positive mode and 0.4% trifluoroacetic acid for anthocyanins and flavonols, negative mode and 0.1% formic acid for phenolic acids and flavanols). Under the optimized LC/MS conditions and based on the analysis of the MS and UV data and in comparison with the authenticated standards, a total of 53 polyphenolic compounds were successfully separated and individually identified including 33 anthocyanins, 12 flavonols, 4 phenolic acids and 4 flavanols/proanthocyanidins. With the method developed, a survey was conducted to qualitatively assess and compare the composition of polyphenols among 29 grapes and grape-derived products. To facilitate the quantitation of the major class of polyphenolic anthocyanidins, a simple and precise acid assisted hydrolysis method was established for the quantitation of anthocyanidins in grape juice samples, grape berries and grape skins using LC/MS. Five most common anthocyanidins of delphenidin, petunidin, cyanidin, malvidin, and peonidin in the hydrolyzed grape extracts were included in the quantification study. The validation of this method showed that the recovery percentages of five anthocyanidins ranged from 98.59 % to 103.20% with the relative standard deviation (RSD) less than 5.03%. The qualitative method provided complete insight into the composition of polyphenols in grapes, and other grape-derived products. This quantitative method provides a rapid and accurate tool to quantitatively study individual anthocyanidin in grapes or grape juice samples for quality control and to facilitate the evaluation and comparison of new commercial grapes or grape juice products in market.M.S.Includes bibliographical referencesby Yanping X
Interaction between culture, fairness and patriotism and its impact on individual preferences and attitudes in economics
No full textBased on data collected from two surveys conducted in Germany and Taiwan, my first paper (Chapter 2) examines the impact of culture through language priming (Chinese vs. German or English) on individuals’ price fairness perception and attitudes towards government intervention and economic policy involving inequality. We document large cross-language differences: in both surveys, subjects who were asked and answered in Chinese demonstrated significantly higher perceived price fairness in a free market mechanism than their counterparts who completed the survey in German or English language. They were also more inclined to accept a Pareto improvement policy which increases social and economic inequality. In the second survey, Chinese language induced also a lower readiness to accept government intervention in markets with price limits compared to English language. Since language functions as a cultural mindset prime, our findings imply that culture plays an important role in fairness perception and preferences regarding social and economic inequality.
Chapter 3 of this work deals with patriotism priming. By conducting two online experimental studies conducted in Germany and China, we tested three different kinds of priming methods for constructive and blind patriotism respectively. Subjects were randomly distributed to one of three treatments motivated by previous studies in different countries: a constructive patriotism priming treatment, a blind patriotism priming treatment and a non-priming baseline. While the first experiment had a between-subject design, the second one enabled both a between-subject and within-subject comparison, since the level of patriotism of individuals was measured before and after priming respectively. The design of the second survey also enabled a comparison among the three priming methods for constructive and blind patriotism. The results showed that the tested methods, especially the national achievements as a priming mechanism, functioned well overall for constructive patriotism.
Surprisingly, the priming for blind patriotism did not work in either Germany or China and the opposite results were observed. Discussion and implications for future studies are provided at the end of the chapter.
Using data from the same studies as in Chapter 3, Chapter 4 examines the impact of patriotism on individuals’ fairness perception and preferences regarding inequality and on their attitudes toward economic policy involving inequality. Across surveys and countries, a positive and significant effect of blind patriotism on economic individualism was found. For China, we also found a significant relationship between blind patriotism and the agreement to unequal economic policy. In contrast to blind patriotism, we did not find an association of constructive patriotism to economic individualism and to attitudes toward economic policy involving inequality. Political and economic implications based on the results are discussed.
The last chapter (Chapter 5) studies the self-serving bias (when an individual’s perception about fairness is biased by self-interest) in the context of price setting and profit distribution. By analyzing data from four surveys conducted in six countries, we found that the stated appropriate product price and the fair allocation of profit was significantly higher, when the outcome was favorable to oneself. This self-serving bias in price fairness perception, however, differed across countries significantly and was significantly higher in Germany, Taiwan and China than in Vietnam, Estonia and Japan.
Although economic individualism and masculinity were found to have a significant negative effect on self-interest bias in price fairness judgment, they did not sufficiently explain the differences in self-interest bias between countries. Furthermore, we also observed an increase of self-interest bias in profit allocation over time in time-series data for one country (Germany) with data from 2011 to 2023.
The four papers are all co-authored with Prof. Marc Oliver Rieger, and the first paper has been accepted for publications in Review of Behavioral Economics
Table_S1 – Supplemental material for Prognostic nomogram for patients with non-metastatic HER2 positive breast cancer in a prospective cohort
No full textSupplemental material, Table_S1 for Prognostic nomogram for patients with non-metastatic HER2 positive breast cancer in a prospective cohort by Chuanxu Luo, Xiaorong Zhong, Zhu Wang, Yu Wang, Yanping Wang, Ping He, Qian Peng and Hong Zheng in The International Journal of Biological Markers</p
Multiscale asymptotic method for Steklov eigenvalue equations in composite media
No full textAuthor name used in this publication: Yanping Lin2012-2013 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishedVoR allowe
Developing finite element methods for maxwell's equations in a cole-cole dispersive medium
No full textAuthor name used in this publication: Yanping Lin2011-2012 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishedVoR allowe
Multiscale asymptotic method for Maxwell's equations in composite materials
No full textAuthor name used in this publication: Yanping Lin2009-2010 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishedVoR allowe
Identification of Novel Regulatory and Target Proteins in the p53 Pathway: APC2 and PFK2
No full textThe Mdm2 proto-oncoprotein is the primary negative regulator for the tumor suppressor p53. While it is believed that Mdm2 degradation is regulated via its own E3 ubiquitin ligase activity, recent development of knock-in mouse models demonstrate that in vivo Mdm2 E3 ligase function is dispensable for the degradation of Mdm2 itself. Here, we show that the anaphase promoting complex/cyclosome (APC/C) is an E3 ubiquitin ligase for Mdm2 degradation. We demonstrate that APC2, a scaffold subunit of APC/C, binds to Mdm2 and is required for Mdm2 polyubiquitination and proteasomal degradation. Downregulation of APC2 by RNAi results in transcription-independent accumulation of Mdm2 and attenuation of stress-induced p53 stabilization, leading to decreased senescence and increased cell survival. Furthermore, APC2 expression is frequently downregulated in human cancers and in tumor cell lines, and often correlates with Mdm2 overexpression. Our study shows the regulation of Mdm2 by APC/C E3 ubiquitin ligase, modifying our understanding of Mdm2 degradation in vivo, and providing important therapeutic implications for tumors with Mdm2 overexpression. Although nucleotide shortage can result in genomic instability and cancer development, relatively little is known regarding the mechanisms responsible for coordinating nucleotide shortage and cell metabolism to maintain a nucleotide pool amenable to DNA replication and DNA damage repair. Here, we provide evidence supporting a model whereby p53-dependent regulation of phosphofructokinase-2 (PFK2) is essential for the redirection of glucose from glycolysis to the pentose phosphate pathway (PPP) under nucleotide shortage stress. Our data show that the suppression of PFK2 is specific to nucleotide shortage. Decreased expression of PFK2 resulted in a decrease in the rate of glycolysis and an increase in PPP activity, leading to an increased nucleotide pool and improved DNA damage repair efficiency. Importantly, exogenously supplied nucleosides effectively rescued the DNA damage repair defect caused by p53 inactivation, further suggesting that the maintenance of the nucleotide pool is an important function of p53. These findings underscore an essential role for p53 in modulating glucose metabolism in response to nucleotide shortage stress, and suggest that the tumor suppressive function of p53 is linked to its role in responding to nucleotide shortage and coordinating metabolic adaptation.Doctor of Philosoph
Edge-unfolding almost-flat convex polyhedral terrains
No full textThesis (M. Eng.)--Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 97-98).In this thesis we consider the centuries-old question of edge-unfolding convex polyhedra, focusing specifically on edge-unfoldability of convex polyhedral terrain which are "almost at" in that they have very small height. We demonstrate how to determine whether cut-trees of such almost-at terrains unfold and prove that, in this context, any partial cut-tree which unfolds without overlap and "opens" at a root edge can be locally extended by a neighboring edge of this root edge. We show that, for certain (but not all) planar graphs G, there are cut-trees which unfold for all almost-at terrains whose planar projection is G. We also demonstrate a non-cut-tree-based method of unfolding which relies on "slice" operations to build an unfolding of a complicated terrain from a known unfolding of a simpler terrain. Finally, we describe several heuristics for generating cut-forests and provide some computational results of such heuristics on unfolding almost-at convex polyhedral terrains.by Yanping Chen.M.Eng
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