59 research outputs found
Polymorphisms of the glucose transporter (GLUT1) gene are associated with diabetic nephropathy
Polymorphisms of the glucose transporter (GLUT1) gene are associated with diabetic nephropathy.BackgroundDiabetic nephropathy (DN) is a major cause of morbidity and mortality in patients with type 1 diabetes mellitus. Recent studies suggest that genetic factors, including polymorphisms in the flanking region of the aldose reductase gene (5′ALR2), play an important role in the pathogenesis of nephropathy. Glucose transporter (GLUT1) activity has been implicated in renal hypertrophy and extracellular matrix formation in mesangial cells. The aim was to investigate the frequency of a polymorphism within the GLUT1 gene in 186 Caucasoid patients with type 1 diabetes and 104 normal controls.MethodsAmplimers flanking the Xba-I polymorphic site in the second intron were employed to amplify DNA from subjects. The amplified DNA was restricted with endonuclease Xba-I, separated by gel electrophoresis, and visualized. In the absence of an Xba-I site, a fragment of 1.1 kilobase was seen, whereas fragments of 0.9 and 0.2 were generated if the Xba-I site was present.ResultsThere was a highly significant increase in the frequency of the 1.1 allele in those patients with nephropathy (N = 70) compared with those with no proteinuria or retinopathy after 20 years of diabetes (uncomplicated N = 44, 61.4 vs. 40.9%, respectively, P < 0.001). The 1.1/1.1 genotype was also significantly increased in the nephropathy group compared with the uncomplicated group of patients (37.1 vs. 13.6%, respectively, P < 0.01). The frequency of the 1.1/1.1 genotype was similar in 30 patients with retinopathy but not nephropathy when compared with the uncomplicated group of patients (13.6 vs. 16.7%). Furthermore, only 8 out of 49 patients with DN had the Z+2 5′ALR2 DN “protective” allele and the 0.9 GLUT1 allele in contrast to 21 out of 39 uncomplicated patients (P < 0.0002).ConclusionThese results suggest that the GLUT1 gene together with the aldose reductase gene are associated with susceptibility to DN in patients with type 1 diabetes
Structural Rounding: Approximation Algorithms for Graphs Near an Algorithmically Tractable Class
We develop a framework for generalizing approximation algorithms from the structural graph algorithm literature so that they apply to graphs somewhat close to that class (a scenario we expect is common when working with real-world networks) while still guaranteeing approximation ratios. The idea is to edit a given graph via vertex- or edge-deletions to put the graph into an algorithmically tractable class, apply known approximation algorithms for that class, and then lift the solution to apply to the original graph. We give a general characterization of when an optimization problem is amenable to this approach, and show that it includes many well-studied graph problems, such as Independent Set, Vertex Cover, Feedback Vertex Set, Minimum Maximal Matching, Chromatic Number, (l-)Dominating Set, Edge (l-)Dominating Set, and Connected Dominating Set.
To enable this framework, we develop new editing algorithms that find the approximately-fewest edits required to bring a given graph into one of a few important graph classes (in some cases these are bicriteria algorithms which simultaneously approximate both the number of editing operations and the target parameter of the family). For bounded degeneracy, we obtain an O(r log{n})-approximation and a bicriteria (4,4)-approximation which also extends to a smoother bicriteria trade-off. For bounded treewidth, we obtain a bicriteria (O(log^{1.5} n), O(sqrt{log w}))-approximation, and for bounded pathwidth, we obtain a bicriteria (O(log^{1.5} n), O(sqrt{log w} * log n))-approximation. For treedepth 2 (related to bounded expansion), we obtain a 4-approximation. We also prove complementary hardness-of-approximation results assuming P != NP: in particular, these problems are all log-factor inapproximable, except the last which is not approximable below some constant factor 2 (assuming UGC)
Legal Ethics in the Digital Age
Ms. deMaine\u27s contribution to the seminar is: Legal Ethics in the Digital Agehttps://www.repository.law.indiana.edu/facbooks/1218/thumbnail.jp
Two Hands Are Better Than One (up to constant factors): Self-Assembly In The 2HAM vs. aTAM
We study the difference between the standard seeded model (aTAM) of tile self-assembly, and the "seedless" two-handed model of tile self-assembly (2HAM). Most of our results suggest that the two-handed model is more powerful. In particular, we show how to simulate any seeded system with a two-handed system that is essentially just a constant factor larger. We exhibit finite shapes with a busy-beaver separation in the number of distinct tiles required by seeded versus two-handed, and exhibit an infinite shape that can be constructed two-handed but not seeded. Finally, we show that verifying whether a given system uniquely assembles a desired supertile is co-NP-complete in the two-handed model, while it was known to be polynomially solvable in the seeded model.National Science Foundation (U.S.) (NSF grant CDI-0941538
Bounded-Degree Polyhedronization of Point Sets
URL to paper listed on conference siteIn 1994 Grunbaum [2] showed, given a point set S
in R3, that it is always possible to construct a polyhedron
whose vertices are exactly S. Such a polyhedron
is called a polyhedronization of S. Agarwal et al. [1]
extended this work in 2008 by showing that a polyhedronization
always exists that is decomposable into
a union of tetrahedra (tetrahedralizable). In the same
work they introduced the notion of a serpentine polyhedronization
for which the dual of its tetrahedralization
is a chain. In this work we present an algorithm
for constructing a serpentine polyhedronization that has
vertices with bounded degree of 7, answering an open
question by Agarwal et al. [1]
Perspectives on involvement in the peer-review process : surveys of patient and public reviewers at two journals
Objective
In 2014/2015, The BMJ and Research Involvement and Engagement (RIE) became the first journals to routinely include patients and the public in the peer review process of journal articles. This survey explores the perspectives and early experiences of these reviewers.
Design
A cross-sectional survey.
Setting and participants
Patient and public reviewers for The BMJ and RIE who have been invited to review.
Results
The response rate was 69% (157/227) for those who had previously reviewed and 31% (67/217) for those who had not yet reviewed. Reviewers described being motivated to review by the opportunity to include the patient voice in the research process, influence the quality of the biomedical literature and ensure it meets the needs of patients. Of the 157 who had reviewed, 127 (81%) would recommend being a reviewer to other patients and carers. 144 (92%) thought more journals should adopt patient and public review. Few reviewers (16/224, 7%) reported concerns about doing open review. Annual acknowledgement on the journals’ websites was welcomed as was free access to journal information. Participants were keen to have access to more online resources and training to improve their reviewing skills. Suggestions on how to improve the reviewing experience included: allowing more time to review; better and more frequent communication; a more user-friendly process; improving guidance on how to review including videos; improving the matching of papers to reviewers’ experience; providing more varied sample reviews and brief feedback on the usefulness of reviews; developing a sense of community among reviewers; and publicising of the contribution that patient and public review brings.
Conclusions
Patient and public reviewers shared practical ideas to improve the reviewing experience and these will be reviewed to enhance the guidance and support given to them
The Rate of Decline of Glomerular Filtration Rate May Not Be Associated with Polymorphism of the PPAR Îł
The aim of the study was to investigate whether a Pro12Ala polymorphism in the peroxisome proliferator-activated receptor gamma 2 (PPARÎł2) gene is associated with the progress of diabetic nephropathy in patients with type 1 diabetes. 197 Caucasian patients with type 1 diabetes and ethnically matched 151 normal healthy controls were genotyped for this polymorphism. Results showed that there were no significant differences in the frequencies of the genotypes and alleles of the polymorphism between groups. Multiple regression analysis in 77 patients demonstrated that the rate of decline in renal function in terms of glomerular filtration rate was significantly correlated to the baseline level of cholesterol (P=0.0014), mean diastolic blood pressure during follow-up period (P=0.019), and baseline level of HbA1c (P=0.022) adjusting for the effect of diabetes duration and gender, but no significant association was found between the polymorphism and the progression of diabetic nephropathy in our studied population. In summary, our results show that the PPARÎł2 polymorphism is unlikely to be associated with the development and progression of the diabetic nephropathy in patients with type 1 diabetes. Further studies in different populations may be warranted to confirm our findings as the sample size in our study was relatively small
Complexity of Reconfiguration in Surface Chemical Reaction Networks
We analyze the computational complexity of basic reconfiguration problems for
the recently introduced surface Chemical Reaction Networks (sCRNs), where
ordered pairs of adjacent species nondeterministically transform into a
different ordered pair of species according to a predefined set of allowed
transition rules (chemical reactions). In particular, two questions that are
fundamental to the simulation of sCRNs are whether a given configuration of
molecules can ever transform into another given configuration, and whether a
given cell can ever contain a given species, given a set of transition rules.
We show that these problems can be solved in polynomial time, are NP-complete,
or are PSPACE-complete in a variety of different settings, including when
adjacent species just swap instead of arbitrary transformation (swap sCRNs),
and when cells can change species a limited number of times (k-burnout). Most
problems turn out to be at least NP-hard except with very few distinct species
(2 or 3)
Bounded-Degree Polyhedronization of Point Sets
Abstract In 1994 GrĂĽnbaum showed that, given a point set S in R 3 , it is always possible to construct a polyhedron whose vertices are exactly S. Such a polyhedron is called a polyhedronization of S. Agarwal et al. extended this work in 2008 by showing that there always exists a polyhedronization that can be decomposed into a union of tetrahedra (tetrahedralizable). In the same work they introduced the notion of a serpentine polyhedronization for which the dual of its tetrahedralization is a chain. In this work we present a randomized algorithm running in O(n log 6 n) expected time that constructs a serpentine polyhedronization that has vertices with degree at most 7, answering an open question by Agarwal et al
Observed methods of cuneiform tablet reconstruction in virtual and real world environments
The reconstruction of fragmented artefacts is a tedious process that consumes many valuable work hours of scholars' time. We believe that such work can be made more efficient via new techniques in interactive virtual environments. The purpose of this research is to explore approaches to the reconstruction of cuneiform tablets in the real and virtual environment, and to address the potential barriers to virtual reconstruction of fragments. In this paper we present the results of an experiment exploring the reconstruction strategies employed by individual users working with tablet fragments in real and virtual environments. Our findings have identified physical factors that users find important to the reconstruction process and further explored the subjective usefulness of stereoscopic 3D in the reconstruction process. Our results, presented as dynamic graphs of interaction, compare the precise order of movement and rotation interactions, and the frequency of interaction achieved by successful and unsuccessful participants with some surprising insights. We present evidence that certain interaction styles and behaviours characterise success in the reconstruction process
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