Elastic shape matching of parameterized surfaces using square root normal fields.

In this paper we define a new methodology for shape analysis of parameterized surfaces, where the main issues are: (1) choice of metric for shape comparisons and (2) invariance to reparameterization. We begin by defining a general elastic metric on the space of parameterized surfaces. The main advantages of this metric are twofold. First, it provides a natural interpretation of elastic shape deformations that are being quantified. Second, this metric is invariant under the action of the reparameterization group. We also introduce a novel representation of surfaces termed square root normal fields or SRNFs. This representation is convenient for shape analysis because, under this representation, a reduced version of the general elastic metric becomes the simple \ensuremathL2\ensuremathL2 metric. Thus, this transformation greatly simplifies the implementation of our framework. We validate our approach using multiple shape analysis examples for quadrilateral and spherical surfaces. We also compare the current results with those of Kurtek et al. [1]. We show that the proposed method results in more natural shape matchings, and furthermore, has some theoretical advantages over previous methods

On the segmentation of astronomical images via level-set methods

Astronomical images are of crucial importance for astronomers since they contain a lot of information about celestial bodies that can not be directly accessible. Most of the information available for the analysis of these objects starts with sky explorations via telescopes and satellites. Unfortunately, the quality of astronomical images is usually very low with respect to other real images and this is due to technical and physical features related to their acquisition process. This increases the percentage of noise and makes more difficult to use directly standard segmentation methods on the original image. In this work we will describe how to process astronomical images in two steps: in the first step we improve the image quality by a rescaling of light intensity whereas in the second step we apply level-set methods to identify the objects. Several experiments will show the effectiveness of this procedure and the results obtained via various discretization techniques for level-set equations.Comment: 24 pages, 59 figures, paper submitte

Delivery of urethral sphincter botulinum toxin injections for treating urinary retention during the COVID19 pandemic

Aims: Urethral sphincter botulinum toxin injections is an alternative treatment for urinary retention in women with Fowler’s syndrome and when access to health services were curtailed during the Covid19 pandemic, we continued to offer treatment to prevent increased demand on catheter services due to a recurrence of urinary retention. We describe our experience delivering safe and timely treatment during this period of lockdowns and restricted access to healthcare. // Methods: We retrospectively reviewed the records of all women with Fowler’s syndrome treated with transperineal urethral sphincter botulinum toxin injection between 23rd March 2020 and 31st December 2021 in a tertiary university hospital and clinical outcomes were recorded. // Results: 15 women (mean age 35.6 ± 10.1 years) received 100U OnabotulinumtoxinA injected into the external urethral sphincter as an out-patient procedure adopting hospital infection control guidelines. 41 injections were administered in total, and 8 (53%) patients received more than 1 injection (median 2 injections/patient, median inter-injection interval 108.5 days). 10 (66.7%) patients reported improvements in urinary symptoms across 31/41 (75.6%) of injections. Side effects were reported after 21.4% of injections which were mild and transient. No patients developed Covid19 within 4 weeks of the hospital visit. // Conclusion: Real-world data shows that transperineal urethral sphincter botulinum toxin injections could be continued safely and effectively during the Covid19 pandemic. This essential outpatient service played an important role in treatment and quality of life for women with Fowler’s syndrome, and avoided an additional burden on the NHS at the time of a health crisis

Synthesis of a Highly Water-Soluble Derivative of Amphotericin B with Attenuated Proinflammatory Activity

Amphotericin B (AmB), a well-known polyene antifungal agent displays a marked tendency to self-associate and, as a consequence, exhibits very poor solubility in water. The therapeutic index of AmB is low, and is associated with significant dose-related nephrotoxicity, as well as acute, infusion-related febrile reactions. Reports in the literature indicate that that toxicity of AmB may be related to the physical state of the drug. Reaction of AmB in dimethylformamide with bis(dimethylaminopropyl)carbodiimide yielded an unexpected N-alkylguanidine/N-acylurea bis-adduct of AmB which was highly water soluble. The absorption spectrum of the AmB derivative in water indicated excellent monomerization, and the anti-fungal activities of reference AmB and its water-soluble derivative against C. albicans were found to be virtually identical. Furthermore, the water-soluble adduct is significantly less active in engaging TLR4 which would suggest that the adduct may be less proinflammatory

Structure-Activity Relationships in Toll-like Receptor-2 agonistic Diacylthioglycerol Lipopeptides

The N-termini of bacterial lipoproteins are acylated with a (S)-(2,3-bisacyloxypropyl)cysteinyl residue. Lipopeptides derived from lipoproteins activate innate immune responses by engaging Toll-like receptor 2 (TLR2), and are highly immunostimulatory and yet without apparent toxicity in animal models. The lipopeptides may therefore be useful as potential immunotherapeutic agents. Previous structure-activity relationships in such lipopeptides have largely been obtained using murine cells and it is now clear that significant species-specific differences exist between human and murine TLR responses. We have examined in detail the role of the highly conserved Cys residue as well as the geometry and stereochemistry of the Cys-Ser dipeptide unit. (R)-diacylthioglycerol analogues are maximally active in reporter gene assays using human TLR2. The Cys-Ser dipeptide unit represents the minimal part-structure, but its stereochemistry was found not to be a critical determinant of activity. The thioether bridge between the diacyl and dipeptide units is crucial, and replacement by an oxoether bridge results in a dramatic decrease in activity

Exquisite Selectivity For Human Toll-like Receptor 8 in Substituted Furo[2,3-c]quinolines

Toll-like receptor (TLR)-8 agonists activate adaptive immune responses by inducing robust production of T helper 1-polarizing cytokines, suggesting that TLR8-active compounds may be promising candidate adjuvants. We synthesized and evaluated hitherto unexplored furo[2,3-c]quinolines and its regioisomeric furo[3,2-c]quinolines, derived via a tandem, one-pot Sonogashira coupling and intramolecular 5 endo-dig cyclization strategy, in a panel of primary screens. We observed a pure TLR8 agonistic activity profile in select furo[2,3-c]quinolines, with maximal potency conferred by a C2-butyl group (EC50: 1.6 µM); shorter, longer, or substituted homologues, as well as compounds bearing C1 substitutions were inactive, which was rationalized by docking studies using the recently-described crystal structure of human TLR8. The best-in-class compound displayed prominent proinflammatory cytokine induction (including interleukin-12 and interleukin-18), but was bereft of interferon-α inducing properties, confirming its high selectivity for human TLR8

Levelset and B-spline deformable model techniques for image segmentation: a pragmatic comparative study

International audienceDeformable contours are now widely used in image segmentation, using different models, criteria and numerical schemes. Some theoretical comparisons between some deformable model methods have already been published. Yet, very few experimental comparative studies on real data have been reported. In this paper,we compare a levelset with a B-spline based deformable model approach in order to understand the mechanisms involved in these widely used methods and to compare both evolution and results on various kinds of image segmentation problems. In general, both methods yield similar results. However, specific differences appear when considering particular problems