1,056 research outputs found
Characterizations of hemirings by their -ideals
In this paper we characterize hemirings in which all -ideals or all fuzzy
-ideals are idempotent. It is proved, among other results, that every
-ideal of a hemiring is idempotent if and only if the lattice of fuzzy
-ideals of is distributive under the sum and -intrinsic product of
fuzzy -ideals or, equivalently, if and only if each fuzzy -ideal of
is intersection of those prime fuzzy -ideals of which contain it. We
also define two types of prime fuzzy -ideals of and prove that, a
non-constant -ideal of is prime in the second sense if and only if each
of its proper level set is a prime -ideal of
Alterations in osteoclast function and phenotype induced by different inhibitors of bone resorption - implications for osteoclast quality
<p>Abstract</p> <p>Background</p> <p>Normal osteoclasts resorb bone by secretion of acid and proteases. Recent studies of patients with loss of function mutations affecting either of these processes have indicated a divergence in osteoclastic phenotypes. These difference in osteoclast phenotypes may directly or indirectly have secondary effects on bone remodeling, a process which is of importance for the pathogenesis of both osteoporosis and osteoarthritis. We treated human osteoclasts with different inhibitors and characterized their resulting function.</p> <p>Methods</p> <p>Human CD14 + monocytes were differentiated into mature osteoclasts using RANKL and M-CSF. The osteoclasts were cultured on bone in the presence or absence of various inhibitors: Inhibitors of acidification (bafilomycin A1, diphyllin, ethoxyzolamide), inhibitors of proteolysis (E64, GM6001), or a bisphosphonate (ibandronate). Osteoclast numbers and bone resorption were monitored by measurements of TRACP activity, the release of calcium, CTX-I and ICTP, as well as by counting resorption pits.</p> <p>Results</p> <p>All inhibitors of acidification were equally potent with respect to inhibition of both organic and inorganic resorption. In contrast, inhibition of proteolysis by E64 potently reduced organic resorption, but only modestly suppressed inorganic resorption. GM6001 alone did not greatly affect bone resorption. However, when GM6001 and E64 were combined, a complete abrogation of organic bone resorption was observed, without a great effect on inorganic resorption. Ibandronate abrogated both organic and inorganic resorption at all concentrations tested [0.3-100 ÎĽM], however, this treatment dramatically reduced TRACP activity.</p> <p>Conclusions</p> <p>We present evidence highlighting important differences with respect to osteoclast function, when comparing the different types of osteoclast inhibitors. Each class of osteoclast inhibitors will lead to different alterations in osteoclast quality, which secondarily may lead to different bone qualities.</p
The Calcitonin and Glucocorticoids Combination: Mechanistic Insights into Their Class-Effect Synergy in Experimental Arthritis
PMCID: PMC3564948This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Automatic Detection of Malignant Masses in Digital Mammograms Based on a MCET-HHO Approach
Digital image processing techniques have become an important process within medical images. These techniques allow the improvement of the images in order to facilitate their interpretation for specialists. Within these are the segmentation methods, which help to divide the images by regions based on different approaches, in order to identify details that may be complex to distinguish initially. In this work, it is proposed the implementation of a multilevel threshold segmentation technique applied to mammography images, based on the Harris Hawks Optimization (HHO) algorithm, in order to identify regions of interest (ROIs) that contain malignant masses. The method of minimum cross entropy thresholding (MCET) is used to select the optimal threshold values for the segmentation. For the development of this work, four mammography images were used (all with presence of a malignant tumor), in their two views, craniocaudal (CC) and mediolateral oblique (MLO), obtained from the Digital Database for Screening Mammography (DDSM). Finally, the ROIs calculated were compared with the original ROIs of the database through a series of metrics, to evaluate the behavior of the algorithm. According to the results obtained, where it is shown that the agreement between the original ROIs and the calculated ROIs is significantly high, it is possible to conclude that the proposal of the MCET-HHO algorithm allows the automatic identification of ROIs containing malignant tumors in mammography images with significant accuracy.Digital image processing techniques have become an important process within medical images. These techniques allow the improvement of the images in order to facilitate their interpretation for specialists. Within these are the segmentation methods, which help to divide the images by regions based on different approaches, in order to identify details that may be complex to distinguish initially. In this work, it is proposed the implementation of a multilevel threshold segmentation technique applied to mammography images, based on the Harris Hawks Optimization (HHO) algorithm, in order to identify regions of interest (ROIs) that contain malignant masses. The method of minimum cross entropy thresholding (MCET) is used to select the optimal threshold values for the segmentation. For the development of this work, four mammography images were used (all with presence of a malignant tumor), in their two views, craniocaudal (CC) and mediolateral oblique (MLO), obtained from the Digital Database for Screening Mammography (DDSM). Finally, the ROIs calculated were compared with the original ROIs of the database through a series of metrics, to evaluate the behavior of the algorithm. According to the results obtained, where it is shown that the agreement between the original ROIs and the calculated ROIs is significantly high, it is possible to conclude that the proposal of the MCET-HHO algorithm allows the automatic identification of ROIs containing malignant tumors in mammography images with significant accuracy
Serum Tau Fragments Predict Return to Play in Concussed Professional Ice Hockey Players
The diagnosis of sports-related concussion is mainly based on subjective clinical symptoms and neuropsychological tests. Therefore, reliable brain injury biomarkers to assess when it is safe to return to play are highly desirable. The overall objective of this study was to evaluate the utility of two newly described tau fragments for diagnosis and prognosis of sports-related concussions. This multi-center prospective cohort study involved all 12 teams of the top professional ice hockey league in Sweden. A total of 288 players consented to participate in the study. Thirty-five players sustained concussions, of whom 28 underwent repeated blood samplings at 1, 12, 36, and 144 h after the trauma, or when the player returned to play (7 to >90 days). There was no significant increase in the levels of Tau-A in post-concussion samples compared with preseason values. However, serum levels of Tau-C were significantly higher in post-concussion samples compared with preseason. Further, levels of Tau-A correlated with the duration of post-concussive symptoms. Tau-A in serum, which is newly discovered biomarker, could be used to predict when it is safe to return to play after a sports-related concussion
Screening of protein kinase inhibitors identifies PKC inhibitors as inhibitors of osteoclastic acid secretion and bone resorption
<p>Abstract</p> <p>Background</p> <p>Bone resorption is initiated by osteoclastic acidification of the resorption lacunae. This process is mediated by secretion of protons through the V-ATPase and chloride through the chloride antiporter ClC-7. To shed light on the intracellular signalling controlling extracellular acidification, we screened a protein kinase inhibitor library in human osteoclasts.</p> <p>Methods</p> <p>Human osteoclasts were generated from CD14+ monocytes. The effect of different kinase inhibitors on lysosomal acidification in human osteoclasts was investigated using acridine orange for different incubation times (45 minutes, 4 and 24 hours). The inhibitors were tested in an acid influx assay using microsomes isolated from human osteoclasts. Bone resorption by human osteoclasts on bone slices was measured by calcium release. Cell viability was measured using AlamarBlue.</p> <p>Results</p> <p>Of the 51 compounds investigated only few inhibitors were positive in both acidification and resorption assays. Rottlerin, GF109203X, Hypericin and Ro31-8220 inhibited acid influx in microsomes and bone resorption, while Sphingosine and Palmitoyl-DL-carnitine-Cl showed low levels of inhibition. Rottlerin inhibited lysosomal acidification in human osteoclasts potently.</p> <p>Conclusions</p> <p>In conclusion, a group of inhibitors all indicated to inhibit PKC reduced acidification in human osteoclasts, and thereby bone resorption, indicating that acid secretion by osteoclasts may be specifically regulated by PKC in osteoclasts.</p
Self-Similarity in General Relativity \endtitle
The different kinds of self-similarity in general relativity are discussed,
with special emphasis on similarity of the ``first'' kind, corresponding to
spacetimes admitting a homothetic vector. We then survey the various classes of
self-similar solutions to Einstein's field equations and the different
mathematical approaches used in studying them. We focus mainly on spatially
homogenous and spherically symmetric self-similar solutions, emphasizing their
possible roles as asymptotic states for more general models. Perfect fluid
spherically symmetric similarity solutions have recently been completely
classified, and we discuss various astrophysical and cosmological applications
of such solutions. Finally we consider more general types of self-similar
models.Comment: TeX document, 53 page
The role of stellar mass and environment for cluster blue fraction, AGN fraction and star-formation indicators from a targeted analysis of Abell 1691
We present an analysis of the galaxy population of the intermediate X-ray
luminosity galaxy cluster, Abell 1691, from SDSS and Galaxy Zoo data to
elucidate the relationships between environment and galaxy stellar mass for a
variety of observationally important cluster populations that include the
Butcher-Oemler blue fraction, the active galactic nucleus (AGN) fraction and
other spectroscopic classifications of galaxies. From 342 cluster members, we
determine a cluster recession velocity of 21257+/-54 km/s and velocity
dispersion of 1009^+40_-36 km/s and show that although the cluster is fed by
multiple filaments of galaxies it does not possess significant sub-structure in
its core. We identify the AGN population of the cluster from a BPT diagram and
show that there is a mild increase in the AGN fraction with radius from the
cluster centre that appears mainly driven by high mass galaxies (log(stellar
mass)>10.8). Although the cluster blue fraction follows the same radial trend,
it is caused primarily by lower mass galaxies (log(stellar mass)<10.8).
Significantly, the galaxies that have undergone recent star-bursts or are
presently star-bursting but dust-shrouded (spectroscopic e(a) class galaxies)
are also nearly exclusively driven by low mass galaxies. We therefore suggest
that the Butcher-Oemler effect may be a mass-dependant effect. We also examine
red and passive spiral galaxies and show that the majority are massive
galaxies, much like the rest of the red and spectroscopically passive cluster
population. We further demonstrate that the velocity dispersion profiles of low
and high mass cluster galaxies are different. Taken together, we infer that the
duty cycle of high and low mass cluster galaxies are markedly different, with a
significant departure in star formation and specific star formation rates
observed beyond r_200 and we discuss these findings.Comment: 17 pages, 14 figures (one degraded due to size constraints), accepted
for publication in MNRA
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