144 research outputs found
Higher rank lamplighter groups are graph automatic
We show that the higher rank lamplighter groups, or Diestel-Leader groups
for , are graph automatic. This introduces a new family
of graph automatic groups which are not automatic
A Sparse Graph Formulation for Efficient Spectral Image Segmentation
Spectral Clustering is one of the most traditional methods to solve
segmentation problems. Based on Normalized Cuts, it aims at partitioning an
image using an objective function defined by a graph. Despite their
mathematical attractiveness, spectral approaches are traditionally neglected by
the scientific community due to their practical issues and underperformance. In
this paper, we adopt a sparse graph formulation based on the inclusion of extra
nodes to a simple grid graph. While the grid encodes the pixel spatial
disposition, the extra nodes account for the pixel color data. Applying the
original Normalized Cuts algorithm to this graph leads to a simple and scalable
method for spectral image segmentation, with an interpretable solution. Our
experiments also demonstrate that our proposed methodology over performs
traditional spectral algorithms for segmentation
CLINICAL STUDY TO EVALUATE THE EFFICACY OF YOGIC SHUDDHIKRIYA (CLEANSING PROCEDURE) AND MADHUDAK (HONEY AND WATER) IN THE MANAGEMENT OF STHAULYA (OBESITY)
Life in today’s materialistic era, has become miserable. As a matter of fact, human life is becoming luxury oriented day by day despite all the odds. According to ecological approach, disease is nothing but a mal-adjustment of human being to his environment. The disruption in environment brings about lifestyle disorders. The sedentary lifestyle of today’s era leads to the non-communicable epidemic of Obesity. Hence for the management of Obesity the therapy which offers modification in the lifestyle will be selected from Yogic Shat-shuddhikriyas i.e. Kapalbhati in comparison with dietary therapy of Madhudak (Honey and Water) as mentioned by Ayurvedic sages. In the present study, 60 patients with features of obesity as per Ayurvedic classics and body mass index more than 25 kg/m2 were selected. This patients will be randomly divided into experimental and control group, containing thirty subjects in each. In experimental group patients were made to perform Kapalbhati yogic shuddhikriya daily at morning whereas in comparison for control group dietary therapy of Madhudak. The study reveals that there was a remarkable decrease in subjective and objective parameters in both the groups, but Kapalbhati therapy is found more effective in every aspects of obesity. Average percentage of relief in experimental group is 27.85% and in control group is 9.93%. Hence to prevent this smoldering problem of present era the ‘Sciences of life’ i.e. Yoga offers the lifestyle modifying, time effective, free of cost, objective therapy (Adravyabhoot chikitsa) through its basic principles
Bone Nanomechanical Properties and Relationship to Bone Turnover and Architecture in Patients With Atypical Femur Fractures: A Prospective Nested Case-Control Study
Atypical femur fractures (AFFs) are well-established serious complication of long-term bisphosphonate and denosumab therapy in patients with osteopenia or osteoporosis. To elucidate underlying mechanism(s) for the development of AFF, we performed a nested case-control study to investigate bone tissue nanomechanical properties and prevailing bone microstructure and tissue-level remodeling status as assessed by bone histomorphometry. We hypothesized that there would be differences in nanomechanical properties between patients with and without AFF and that bone microstructure and remodeling would be related to nanomechanical properties. Thirty-two full-thickness transiliac bone biopsies were obtained from age- and sex-matched patients on long-term bisphosphonate therapy with (n = 16) and without an AFF (n = 16). Standard histomorphometric measurements were made in each sample on three different bone envelopes (cancellous, intracortical, and endosteal). Iliac bone wall thickness was significantly lower on all three bone surfaces in patients with AFF than in those without AFF. Surface-based bone formation rate was suppressed similarly in both groups in comparison to healthy premenopausal and postmenopausal women, with no significant difference between the two groups. Nanoindentation was used to assess material properties of cortical and cancellous bone separately. Elastic modulus was higher in cortical than in cancellous bone in patients with AFF as well as compared to the elastic modulus of cortical bone from non-AFF patients. However, the elastic modulus of the cancellous bone was not different between AFF and non-AFF groups or between cortical and cancellous bone of non-AFF patients. Resistance to plastic deformation was decreased in cortical bone in both AFF and non-AFF groups compared to cancellous bone, but to a greater extent in AFF patients. We conclude that long-term bisphosphonate therapy is associated with prolonged suppression of bone turnover resulting in altered cortical remodeling and tissue nanomechanical properties leading to AFF
Pharmacological distinction between dantrolene and ryanodine binding sites: evidence from normal and malignant hyperthermia-susceptible porcine skeletal muscle
Effects of Dantrolene on Steps of Excitation-Contraction Coupling in Mammalian Skeletal Muscle Fibers
The Structure of the NPC1L1 N-Terminal Domain in a Closed Conformation
NPC1L1 is the molecular target of the cholesterol lowering drug Ezetimibe and mediates the intestinal absorption of cholesterol. Inhibition or deletion of NPC1L1 reduces intestinal cholesterol absorption, resulting in reduction of plasma cholesterol levels.Here we present the 2.8 Ã… crystal structure of the N-terminal domain (NTD) of NPC1L1 in the absence of cholesterol. The structure, combined with biochemical data, reveals the mechanism of cholesterol selectivity of NPC1L1. Comparison to the cholesterol free and bound structures of NPC1(NTD) reveals that NPC1L1(NTD) is in a closed conformation and the sterol binding pocket is occluded from solvent.The structure of NPC1L1(NTD) reveals a degree of flexibility surrounding the entrance to the sterol binding pocket, suggesting a gating mechanism that relies on multiple movements around the entrance to the sterol binding pocket
Dependence of Bone Yield (Volume of Bone Formed per Unit of Cement Surface Area) on Resorption Cavity Size During Osteonal Remodeling in Human Rib: Implications for Osteoblast Function and the Pathogenesis of Age-Related Bone Loss
It is both a necessary and a sufficient condition for bone to be lost with age at any surface location that during remodeling the replacement of resorbed bone is incomplete. In both the ilium and the rib, the degree of such focal imbalance is smaller on the intracortical than on the endocortical or cancellous surfaces that are adjacent to bone marrow. The reason for this difference is unknown. To further examine this question, we measured various geometric variables in 1263 osteons in rib cross sections from 65 persons, including both sexes and age ranges 20 to 30 years and 60 to 70 years (four groups). Haversian canal (HC) area did not differ significantly between sexes or age groups. Percent osteonal refilling was close to 95% in all groups and did not differ between sexes but fell slightly with age. There was a very highly significant linear relationship between osteon bone area and (osteon area + HC area) in all groups, with coefficients of determination (r2) greater than 0.98. The regression slopes declined slightly with age in women but not in men. There was a very highly significant quadratic relationship between osteon bone area and osteon perimeter in all groups, with r2 values greater than 0.97. The ratio osteon bone area:osteon perimeter, an index of bone yield—the volume of bone deposited on each unit area of cement surface—was strongly related to osteon area and did not differ between sexes but was slightly less in the older groups. We conclude the following: (1) The high efficiency of intracortical remodeling in the rib is confirmed, with only trivial effects of age. (2) For HC area to be maintained within narrow limits and bone balance preserved, either initial osteoblast density or osteoblast capacity (the two determinants of bone yield) or, most likely, both must increase progressively with the size of the resorption cavity, suggesting that osteoblast recruitment (relative to available surface) and osteoblast lifespan increase with the volume of bone resorbed. (3) Intracortical remodeling in the rib is more efficient than marrow-adjacent remodeling at any site, possibly because of the different relationships to the circulation. In osteonal remodeling, all molecules released from resorbed bone must travel past the sites of osteoblast recruitment and operation, but in hemiosteonal remodeling, some molecules may not be subject to this constraint. (4) If marrow-adjacent remodeling became as efficient as rib intracortical remodeling, age-related bone loss would cease to be an important medical problem. © 2010 American Society for Bone and Mineral Researc
DiMANI: diffusion MRI for anatomical nuclei imaging—Application for the direct visualization of thalamic subnuclei
The thalamus is a centrally located and heterogeneous brain structure that plays a critical role in various sensory, motor, and cognitive processes. However, visualizing the individual subnuclei of the thalamus using conventional MRI techniques is challenging. This difficulty has posed obstacles in targeting specific subnuclei for clinical interventions such as deep brain stimulation (DBS). In this paper, we present DiMANI, a novel method for directly visualizing the thalamic subnuclei using diffusion MRI (dMRI). The DiMANI contrast is computed by averaging, voxelwise, diffusion-weighted volumes enabling the direct distinction of thalamic subnuclei in individuals. We evaluated the reproducibility of DiMANI through multiple approaches. First, we utilized a unique dataset comprising 8 scans of a single participant collected over a 3-year period. Secondly, we quantitatively assessed manual segmentations of thalamic subnuclei for both intra-rater and inter-rater reliability. Thirdly, we qualitatively correlated DiMANI imaging data from several patients with Essential Tremor with the localization of implanted DBS electrodes and clinical observations. Lastly, we demonstrated that DiMANI can provide similar features at 3T and 7T MRI, using varying numbers of diffusion directions. Our results establish that DiMANI is a reproducible and clinically relevant method to directly visualize thalamic subnuclei. This has significant implications for the development of new DBS targets and the optimization of DBS therapy
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