5,278 research outputs found
Molecular definition of a narrow interval at 7q22.1 associated with myelodysplasia
Chromosome 7 translocations, deletions, or monosomy are associated with myelodysplasia (MDS) and acute myeloid leukemia both in children and adults. These chromosomal anomalies represent one of the most common cytogenetic abnormalities associated with these diseases and usually herald a poor prognosis. In this study two cosmid DNA probes that mapped to 7q22.1 and were known to be separated by approximately 500 kb were identified to flank the proximal inversion breakpoint in a patient carrying a constitutional inversion (7q22.1-34) associated with MDS. A yeast artificial chromosome (YAC) clone that encompassed the two cosmids was identified and shown to span the breakpoint. Fluorescence in situ hybridization was then used to analyze six additional patients with myelodysplasia and chromosomal rearrangements of the 7q22 region (three patients had translocations and three carried deletions). The breakpoint in one of the patients was found to be contained within the same YAC clone that spanned the inversion breakpoint. Moreover, this same interval was determined to be absent in all three patients with chromosomal deletions. These results suggest that this segment of DNA on chromosome 7q22.1 may contain specific gene(s) that have a significant role in myeloid malignancies.link_to_OA_fulltex
OneGAN: Simultaneous Unsupervised Learning of Conditional Image Generation, Foreground Segmentation, and Fine-Grained Clustering
We present a method for simultaneously learning, in an unsupervised manner,
(i) a conditional image generator, (ii) foreground extraction and segmentation,
(iii) clustering into a two-level class hierarchy, and (iv) object removal and
background completion, all done without any use of annotation. The method
combines a Generative Adversarial Network and a Variational Auto-Encoder, with
multiple encoders, generators and discriminators, and benefits from solving all
tasks at once. The input to the training scheme is a varied collection of
unlabeled images from the same domain, as well as a set of background images
without a foreground object. In addition, the image generator can mix the
background from one image, with a foreground that is conditioned either on that
of a second image or on the index of a desired cluster. The method obtains
state of the art results in comparison to the literature methods, when compared
to the current state of the art in each of the tasks.Comment: To be published in the European Conference on Computer Vision (ECCV)
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Design and function of superfast muscles : new insights into the physiology of skeletal muscle
First published online as a Review in Advance on October 24, 2005. (Some corrections may occur before final publication online and in print)Author Posting. © Annual Reviews, 2005. This article is posted here by permission of Annual Reviews for personal use, not for redistribution. The definitive version was published in Annual Review of Physiology 68 (2006): 22.1-22.29, doi:10.1146/annurev.physiol.68.040104.105418.Superfast muscles of vertebrates power sound production. The fastest, the swimbladder muscle of toadfish, generates mechanical power at frequencies in excess of 200 Hz. To operate at these frequencies, the speed of relaxation has had to increase approximately 50-fold. This increase is accomplished by modifications of three kinetic traits: (a) a fast calcium transient due to extremely high concentration of sarcoplasmic reticulum (SR)-Ca2+ pumps and parvalbumin, (b) fast off-rate of Ca2+ from troponin C due to an alteration in troponin, and (c) fast cross-bridge detachment rate constant (g, 50 times faster than that in rabbit fast-twitch muscle) due to an alteration in myosin. Although these three modifications permit swimbladder muscle to generate mechanical work at high frequencies (where locomotor muscles cannot), it comes with a cost: The high g causes a large reduction in attached force-generating cross-bridges, making the swimbladder incapable of powering low-frequency locomotory movements. Hence the locomotory and sound-producing muscles have mutually exclusive designs.This work was made possible by support from NIH grants AR38404 and AR46125
as well as the University of Pennsylvania Research Foundation
X-Net: Brain Stroke Lesion Segmentation Based on Depthwise Separable Convolution and Long-range Dependencies
The morbidity of brain stroke increased rapidly in the past few years. To
help specialists in lesion measurements and treatment planning, automatic
segmentation methods are critically required for clinical practices. Recently,
approaches based on deep learning and methods for contextual information
extraction have served in many image segmentation tasks. However, their
performances are limited due to the insufficient training of a large number of
parameters, which sometimes fail in capturing long-range dependencies. To
address these issues, we propose a depthwise separable convolution based X-Net
that designs a nonlocal operation namely Feature Similarity Module (FSM) to
capture long-range dependencies. The adopted depthwise convolution allows to
reduce the network size, while the developed FSM provides a more effective,
dense contextual information extraction and thus facilitates better
segmentation. The effectiveness of X-Net was evaluated on an open dataset
Anatomical Tracings of Lesions After Stroke (ATLAS) with superior performance
achieved compared to other six state-of-the-art approaches. We make our code
and models available at https://github.com/Andrewsher/X-Net.Comment: MICCAI 201
SESAME: Semantic Editing of Scenes by Adding, Manipulating or Erasing Objects
Recent advances in image generation gave rise to powerful tools for semantic
image editing. However, existing approaches can either operate on a single
image or require an abundance of additional information. They are not capable
of handling the complete set of editing operations, that is addition,
manipulation or removal of semantic concepts. To address these limitations, we
propose SESAME, a novel generator-discriminator pair for Semantic Editing of
Scenes by Adding, Manipulating or Erasing objects. In our setup, the user
provides the semantic labels of the areas to be edited and the generator
synthesizes the corresponding pixels. In contrast to previous methods that
employ a discriminator that trivially concatenates semantics and image as an
input, the SESAME discriminator is composed of two input streams that
independently process the image and its semantics, using the latter to
manipulate the results of the former. We evaluate our model on a diverse set of
datasets and report state-of-the-art performance on two tasks: (a) image
manipulation and (b) image generation conditioned on semantic labels
MnSb2O6: a polar magnet with a chiral crystal structure
Structural and magnetic chiralities are found to coexist in a small group of materials in which they produce intriguing phenomenologies such as the recently discovered Skyrmion phases. Here, we describe a previously unknown manifestation of this interplay in MnSb2O6, a trigonal oxide with a chiral crystal structure. Unlike all other known cases, the MnSb2O6 magnetic structure is based on corotating cycloids rather than helices. The coupling to the structural chirality is provided by a magnetic axial vector, related to the so-called vector chirality. We show that this unique arrangement is the magnetic ground state of the symmetric-exchange Hamiltonian, based on ab initio theoretical calculations of the Heisenberg exchange interactions, and is stabilized by out-of-plane anisotropy. MnSb2O6 is predicted to be multiferroic with a unique ferroelectric switching mechanism.open4
Assessing architectural evolution: A case study
This is the post-print version of the Article. The official published can be accessed from the link below - Copyright @ 2011 SpringerThis paper proposes to use a historical perspective on generic laws, principles,
and guidelines, like Lehman’s software evolution laws and Martin’s design principles, in order to achieve a multi-faceted process and structural assessment of a system’s architectural evolution. We present a simple structural model with associated historical metrics and
visualizations that could form part of an architect’s dashboard. We perform such an assessment for the Eclipse SDK, as a case study of a large, complex, and long-lived system for which sustained effective architectural evolution is paramount. The twofold aim of checking generic principles on a well-know system is, on the one hand,
to see whether there are certain lessons that could be learned for best practice of architectural evolution, and on the other hand to get more insights about the applicability of such principles. We find that while the Eclipse SDK does follow several of the laws and principles, there are some deviations, and we discuss areas of architectural improvement and limitations of the assessment approach
Molecular basis for the folding of β-helical autotransporter passenger domains
Bacterial autotransporters comprise a C-terminal β-barrel domain, which must be correctly folded and inserted into the outer membrane to facilitate translocation of the N-terminal passenger domain to the cell exterior. Once at the surface, the passenger domains of most autotransporters are folded into an elongated β-helix. In a cellular context, key molecules catalyze the assembly of the autotransporter β-barrel domain. However, how the passenger domain folds into its functional form is poorly understood. Here we use mutational analysis on the autotransporter Pet to show that the β-hairpin structure of the fifth extracellular loop of the β-barrel domain has a crucial role for passenger domain folding into a β-helix. Bioinformatics and structural analyses, and mutagenesis of a homologous autotransporter, suggest that this function is conserved among autotransporter proteins with β-helical passenger domains. We propose that the autotransporter β-barrel domain is a folding vector that nucleates folding of the passenger domain
A survey of UK medical schools' arrangements for early patient contact
Background: Many U.K. medical schools have patient contact in the first two years of the undergraduate course. Aim: To compare the purposes and organization of early patient contact in UK medical schools and to relate these arrangements to the schools' curricular objectives. Methods: A telephone survey of lead educators in UK medicals schools. Categories of contact were plotted against phases of the course to discern patterns of organisation. Results: The quantity of contact varies considerably (four to 65 days). There is a pattern, with learning objectives around the social context of health and illness preceding skills based work and integrated clinical knowledge for practice coming later. Schools fall into three categories: close adherence to the preclinical/clinical split, with limited early contact acting as an introduction to social aspects of health; provision of substantial patient contact to maximize the integration of knowledge and skills; and transitional, with limited clinical goals. General practice provides between one third and one half of early patient contact. Conclusions: Arrangements meet the objectives set by each school and reflect differing educational philosophies. Change is toward more early contact. There appears to be no national guidance which supports a minimum quantity of patient contact or specific educational purpose in the early years of U.K. basic medical training
Scallop swimming kinematics and muscle performance: modelling the effects of "within-animal" variation in temperature sensitivity
Escape behaviour was investigated in Queen scallops (Aequipecten opercularis) acclimated to 5, 10 or 15 degrees C and tested at their acclimation temperature. Scallops are active molluscs, able to escape from predators by jet-propelled swimming using a striated muscle working in opposition to an elastic hinge ligament. The first cycle of the escape response was recorded using high-speed video ( 250 Hz) and whole-animal velocity and acceleration determined. Muscle shortening velocity, force and power output were calculated using measurements of valve movement and jet area, and a simple biomechanical model. The average shortening speed of the adductor muscle had a Q(10) of 2.04, significantly reducing the duration of the jetting phase of the cycle with increased temperature. Muscle lengthening velocity and the overall duration of the clap cycle were changed little over the range 5 - 15 degrees C, as these parameters were controlled by the relatively temperature-insensitive, hinge ligament. Improvements in the average power output of the adductor muscle over the first clap cycle ( 222 vs. 139 W kg(-1) wet mass at 15 and 5 degrees C respectively) were not translated into proportional increases in overall swimming velocity, which was only 32% higher at 15 degrees C ( 0.37m s(-1)) than 5 degrees C (0.28 m s(-1))
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