Image Smoothing Via Gradient Sparsity and Surface Area Minimization

2019 ◽  
Author(s):  
Jun Liu ◽  
Ming Yan ◽  
Jinshan Zeng ◽  
Tieyong Zeng
Keyword(s):  
Surface Area ◽  
Image Smoothing ◽  
Area Minimization

scholarly journals Microfluidic trapping of vesicles reveals membrane-tension dependent FtsZ cytoskeletal re-organisation

2019 ◽  
Author(s):  
Kristina A. Ganzinger ◽  
Adrián Merino-Salomón ◽  
Daniela A. García-Soriano ◽  
A. Nelson Butterfield ◽  
Thomas Litschel ◽  
...  
Keyword(s):  
Cell Division ◽  
Synthetic Biology ◽  
Surface Area ◽  
Chemical Reactions ◽  
Microfluidic Chip ◽  
Self Organization ◽  
Membrane Tension ◽  
Area Minimization ◽  
Z Ring ◽  
Membrane Bound

AbstractThe geometry of reaction compartments can affect the outcome of chemical reactions. Synthetic biology commonly uses giant unilamellar vesicles (GUVs) to generate cell-sized, membrane-bound reaction compartments. However, these liposomes are always spherical due to surface area minimization. Here, we have developed a microfluidic chip to trap and reversibly deform GUVs into rod- or cigar-like shapes, including a constriction site in the trap mimicking the membrane furrow in cell division. When we introduce into these GUVs the bacterial tubulin homologue FtsZ, the primary protein of the bacterial Z ring, we find that FtsZ organization changes from dynamic rings to elongated filaments upon GUV deformation, and that these FtsZ filaments align preferentially with the short GUV axis, in particular at the membrane neck. In contrast, pulsing Min oscillations in GUVs remained largely unaffected. We conclude that microfluidic traps are a useful tool for deforming GUVs into non-spherical membrane shapes, akin to those seen in cell division, and for investigating the effect of confinement geometry on biochemical reactions, such as protein filament self-organization.

Triangulation of Branching Contours Using Area Minimization

1998 ◽  
Vol 08 (04) ◽  
pp. 389-406 ◽  
Author(s):  
Mu Hong ◽  
Thomas W. Sederberg ◽  
Krzysztof S. Klimaszewski ◽  
Kazufumi Kaneda
Keyword(s):  
Surface Area ◽  
Piecewise Linear ◽  
New Method ◽  
Minimum Surface ◽  
Area Minimization ◽  
Current Algorithm ◽  
Minimum Surface Area ◽  
Minimal Area

This paper presents a new method for reconstructing piecewise linear surfaces from planar polygonal contours that branch. For non-branching contours, experience has shown that the piecewise linear surface of minimum surface area which connects a pair of contours often provides a good solution. The current algorithm extends this idea by searching for the surface of minimal area which connects two contours comprised of more than one polygon. Several examples that justify this heuristic are provided.

Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

1988 ◽  
Vol 46 ◽  
pp. 946-947
Author(s):  
A. Legrouri
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Vanadium Pentoxide ◽  
High Purity ◽  
Gas Adsorption ◽  
Rhodium Catalyst ◽  
Optical Methods ◽  
Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

Cell morphology, volume, and surface area determinations from multilevel contouring within HVEM micrographs of serial sections and whole-cell mounts

1987 ◽  
Vol 45 ◽  
pp. 588-589
Author(s):  
M. Marko ◽  
A. Leith ◽  
D. Parsons
Keyword(s):  
Surface Area ◽  
Electron Micrographs ◽  
Cell Morphology ◽  
Individual Variation ◽  
Serial Section ◽  
Stereo Pair ◽  
Complex Structures ◽  
Serial Sections ◽  
Surface Areas ◽  
Computer Based

The use of serial sections and computer-based 3-D reconstruction techniques affords an opportunity not only to visualize the shape and distribution of the structures being studied, but also to determine their volumes and surface areas. Up until now, this has been done using serial ultrathin sections.The serial-section approach differs from the stereo logical methods of Weibel in that it is based on the Information from a set of single, complete cells (or organelles) rather than on a random 2-dimensional sampling of a population of cells. Because of this, it can more easily provide absolute values of volume and surface area, especially for highly-complex structures. It also allows study of individual variation among the cells, and study of structures which occur only infrequently.We have developed a system for 3-D reconstruction of objects from stereo-pair electron micrographs of thick specimens.

Risk Factors for Bleeding during Treatment of Acute Venous Thromboembolism

1996 ◽  
Vol 76 (05) ◽  
pp. 682-688 ◽  
Author(s):  
Jos P J Wester ◽  
Harold W de Valk ◽  
Karel H Nieuwenhuis ◽  
Catherine B Brouwer ◽  
Yolanda van der Graaf ◽  
...  
Keyword(s):  
Risk Factors ◽  
Venous Thromboembolism ◽  
Surface Area ◽  
Body Surface Area ◽  
Body Surface ◽  
Small Body ◽  
Bleeding Risk ◽  
Risk Scores ◽  
Risk Of Bleeding ◽  
Acute Venous Thromboembolism

Summary Objective: Identification of risk factors for bleeding and prospective evaluation of two bleeding risk scores in the treatment of acute venous thromboembolism. Design: Secondary analysis of a prospective, randomized, assessor-blind, multicenter clinical trial. Setting: One university and 2 regional teaching hospitals. Patients: 188 patients treated with heparin or danaparoid for acute venous thromboembolism. Measurements: The presenting clinical features, the doses of the drugs, and the anticoagulant responses were analyzed using univariate and multivariate logistic regression analysis in order to evaluate prognostic factors for bleeding. In addition, the recently developed Utrecht bleeding risk score and Landefeld bleeding risk index were evaluated prospectively. Results: Major bleeding occurred in 4 patients (2.1%) and minor bleeding in 101 patients (53.7%). For all (major and minor combined) bleeding, body surface area ≤2 m2 (odds ratio 2.3, 95% Cl 1.2-4.4; p = 0.01), and malignancy (odds ratio 2.4, 95% Cl 1.1-4.9; p = 0.02) were confirmed to be independent risk factors. An increased treatment-related risk of bleeding was observed in patients treated with high doses of heparin, independent of the concomitant activated partial thromboplastin time ratios. Both bleeding risk scores had low diagnostic value for bleeding in this sample of mainly minor bleeders. Conclusions: A small body surface area and malignancy were associated with a higher frequency of bleeding. The bleeding risk scores merely offer the clinician a general estimation of the risk of bleeding. In patients with a small body surface area or in patients with malignancy, it may be of interest to study whether limited dose reduction of the anticoagulant drug may cause less bleeding without affecting efficacy.

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