Endovenous laser ablation therapy in children: applications and outcomes

BACKGROUND: Endovenous laser ablation is well recognized as the first-line treatment for superficial venous reflux with varicose veins in adults. It is not widely reported and is not an established practice in pediatric patients. OBJECTIVE: To illustrate a variety of pediatric venous conditions in which endovenous laser ablation can be utilized and to demonstrate its feasibility and safety in children. MATERIALS AND METHODS: We conducted a retrospective review of endovenous laser ablation procedures performed between January 2007 and July 2014 at two large pediatric institutions. RESULTS: We included 35 patients (17 males) who underwent endovenous laser ablation to 43 veins. Median age at first treatment was 14 years (range: 3-18 years). Median weight was 56 kg (range: 19-97 kg). Underlying diagnoses were common venous malformation (15), Klippel-Trenaunay syndrome (8), superficial venous reflux with varicose veins (5), verrucous hemangioma-related phlebectasia (4), venous varix (2) and arteriovenous fistula (1). The most common aim of treatment was to facilitate sclerotherapy. Thirty-four patients had treatment in the lower limbs and one patient in an upper limb. Ten of the veins treated with endovenous laser ablation had an additional procedure performed to close the vein. Complications attributable to endovenous laser ablation occurred in two patients (6%). One patient experienced post-procedural pain and one patient developed a temporary sensory nerve injury. Median clinical follow-up was 13 months (range: 28 days-5.7 years). The aim of the treatment was achieved in 29 of the 35 (83%) patients. CONCLUSION: Endovenous laser ablation is technically feasible and safe in children. It can be used in the management of a range of pediatric venous diseases with good outcomes

Propensity score analysis in the Genetic Analysis Workshop 17 simulated data set on independent individuals

Genetic Analysis Workshop 17 provided simulated phenotypes and exome sequence data for 697 independent individuals (209 case subjects and 488 control subjects). The disease liability in these data was influenced by multiple quantitative traits. We addressed the lack of statistical power in this small data set by limiting the genomic variants included in the study to those with potential disease-causing effect, thereby reducing the problem of multiple testing. After this adjustment, we could readily detect two common variants that were strongly associated with the quantitative trait Q1 (C13S523 and C13S522). However, we found no significant associations with the affected status or with any of the other quantitative traits, and the relationship between disease status and genomic variants remained obscure. To address the challenge of the multivariate phenotype, we used propensity scores to combine covariates with genetic risk factors into a single risk factor and created a new phenotype variable, the probability of being affected given the covariates. Using the propensity score as a quantitative trait in the case-control analysis, we again could identify the two common single-nucleotide polymorphisms (C13S523 and C13S522). In addition, this analysis captured the correlation between Q1 and the affected status and reduced the problem of multiple testing. Although the propensity score was useful for capturing and clarifying the genetic contributions of common variants to the disease phenotype and the mediating role of the quantitative trait Q1, the analysis did not increase power to detect rare variants

An ISO and IUE study of planetary nebula NGC 2440

The infrared and ultraviolet spectra of planetary nebula NGC2440 are presented. The observations were made by the Infrared Space Observatory (ISO) and the International Ultraviolet Explorer (IUE). These data, in conjunction with published optical observations have been used to derive electron temperature and density. The electron temperature increases with increasing ionization potential, from 11 000 to 18 000 K. The electron density has a constant value of 4500 cm(-3) in agreement with previous determinations. The chemical abundance has been derived for the following elements; helium, carbon, nitrogen, oxygen, neon, sulfur and argon. The ionization correction factor turns out to be very small for all species except sulfur

Design Principles for Plasmonic Nanoparticle Devices

For all applications of plasmonics to technology it is required to tailor the resonance to the optical system in question. This chapter gives an understanding of the design considerations for nanoparticles needed to tune the resonance. First the basic concepts of plasmonics are reviewed with a focus on the physics of nanoparticles. An introduction to the finite element method is given with emphasis on the suitability of the method to nanoplasmonic device simulation. The effects of nanoparticle shape on the spectral position and lineshape of the plasmonic resonance are discussed including retardation and surface curvature effects. The most technologically important plasmonic materials are assessed for device applicability and the importance of substrates in light scattering is explained. Finally the application of plasmonic nanoparticles to photovoltaic devices is discussed.Comment: 29 pages, 15 figures, part of an edited book: "Linear and Non-Linear Nanoplasmonics

Cosmic Hydrogen Was Significantly Neutral a Billion Years After the Big Bang

The ionization fraction of cosmic hydrogen, left over from the big bang, provides crucial fossil evidence for when the first stars and quasar black holes formed in the infant universe. Spectra of the two most distant quasars known show nearly complete absorption of photons with wavelengths shorter than the Ly-alpha transition of neutral hydrogen, indicating that hydrogen in the intergalactic medium (IGM) had not been completely ionized at a redshift z~6.3, about a billion years after the big bang. Here we show that the radii of influence of ionizing radiation from these quasars imply that the surrounding IGM had a neutral hydrogen fraction of tens of percent prior to the quasar activity, much higher than previous lower limits of ~0.1%. When combined with the recent inference of a large cumulative optical depth to electron scattering after cosmological recombination from the WMAP data, our result suggests the existence of a second peak in the mean ionization history, potentially due to an early formation episode of the first stars.Comment: 14 Pages, 2 Figures. Accepted for publication in Nature. Press embargo until publishe

Chromatic Illumination Discrimination Ability Reveals that Human Colour Constancy Is Optimised for Blue Daylight Illuminations

The phenomenon of colour constancy in human visual perception keeps surface colours constant, despite changes in their reflected light due to changing illumination. Although colour constancy has evolved under a constrained subset of illuminations, it is unknown whether its underlying mechanisms, thought to involve multiple components from retina to cortex, are optimised for particular environmental variations. Here we demonstrate a new method for investigating colour constancy using illumination matching in real scenes which, unlike previous methods using surface matching and simulated scenes, allows testing of multiple, real illuminations. We use real scenes consisting of solid familiar or unfamiliar objects against uniform or variegated backgrounds and compare discrimination performance for typical illuminations from the daylight chromaticity locus (approximately blue-yellow) and atypical spectra from an orthogonal locus (approximately red-green, at correlated colour temperature 6700 K), all produced in real time by a 10-channel LED illuminator. We find that discrimination of illumination changes is poorer along the daylight locus than the atypical locus, and is poorest particularly for bluer illumination changes, demonstrating conversely that surface colour constancy is best for blue daylight illuminations. Illumination discrimination is also enhanced, and therefore colour constancy diminished, for uniform backgrounds, irrespective of the object type. These results are not explained by statistical properties of the scene signal changes at the retinal level. We conclude that high-level mechanisms of colour constancy are biased for the blue daylight illuminations and variegated backgrounds to which the human visual system has typically been exposed

Using sequence data to identify alternative routes and risk of infection: a case-study of campylobacter in Scotland

<b>Background:</b> Genetic typing data are a potentially powerful resource for determining how infection is acquired. In this paper MLST typing was used to distinguish the routes and risks of infection of humans with Campylobacter jejuni from poultry and ruminant sources.<p></p> <b>Methods:</b> C. jejuni samples from animal and environmental sources and from reported human cases confirmed between June 2005 and September 2006 were typed using MLST. The STRUCTURE software was used to assign the specific sequence types of the sporadic human cases to a particular source. We then used mixed case-case logistic regression analysis to compare the risk factors for being infected with C. jejuni from different sources.<p></p> <b>Results:</b> A total of 1,599 (46.3%) cases were assigned to poultry, 1,070 (31.0%) to ruminant and 67 (1.9%) to wild bird sources; the remaining 715 (20.7%) did not have a source that could be assigned with a probability of greater than 0.95. Compared to ruminant sources, cases attributed to poultry sources were typically among adults (odds ratio (OR) = 1.497, 95% confidence intervals (CIs) = 1.211, 1.852), not among males (OR = 0.834, 95% CIs = 0.712, 0.977), in areas with population density of greater than 500 people/km(2) (OR = 1.213, 95% CIs = 1.030, 1.431), reported in the winter (OR = 1.272, 95% CIs = 1.067, 1.517) and had undertaken recent overseas travel (OR = 1.618, 95% CIs = 1.056, 2.481). The poultry assigned strains had a similar epidemiology to the unassigned strains, with the exception of a significantly higher likelihood of reporting overseas travel in unassigned strains.<p></p> <b>Conclusions:</b> Rather than estimate relative risks for acquiring infection, our analyses show that individuals acquire C. jejuni infection from different sources have different associated risk factors. By enhancing our ability to identify at-risk groups and the times at which these groups are likely to be at risk, this work allows public health messages to be targeted more effectively. The rapidly increasing capacity to conduct genetic typing of pathogens makes such traced epidemiological analysis more accessible and has the potential to substantially enhance epidemiological risk factor studies

Chronic ringworm infestation and Marjolin’s ulcer, an association unknown in the literature

We report here a case of Marjolin’s ulcer developing in a long-standing, inadequately treated, chronic ringworm infestation of the lower limb. A 35-year-old female patient with a ten-year history of a chronic ringworm infestation had developed a nonhealing ulcer in an area of infestation on the right leg. A biopsy revealed well-differentiated squamous cell carcinoma associated with the ringworm infection. A below-knee amputation by an inguinal block dissection was performed. We conclude that proper and timely treatment of fungal infections of the skin is needed to allow for healing of dermal infections and thus the prevention of the disastrous consequences that recurrent mechanical trauma from scratching of the affected area, leading to occult malignancy, which may occur in a small number of patients

Taking the pulse of Mars via dating of a plume-fed volcano

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. The attached file is the published version of the article

The crystal structure of the Hazara virus nucleocapsid protein

Background: Hazara virus (HAZV) is a member of the Bunyaviridae family of segmented negative stranded RNA viruses, and shares the same serogroup as Crimean-Congo haemorrhagic fever virus (CCHFV). CCHFV is responsible for fatal human disease with a mortality rate approaching 30 %, which has an increased recent incidence within southern Europe. There are no preventative or therapeutic treatments for CCHFV-mediated disease, and thus CCHFV is classified as a hazard group 4 pathogen. In contrast HAZV is not associated with serious human disease, although infection of interferon receptor knockout mice with either CCHFV or HAZV results in similar disease progression. To characterise further similarities between HAZV and CCHFV, and support the use of HAZV as a model for CCHFV infection, we investigated the structure of the HAZV nucleocapsid protein (N) and compared it to CCHFV N. N performs an essential role in the viral life cycle by encapsidating the viral RNA genome, and thus, N represents a potential therapeutic target. Results: We present the purification, crystallisation and crystal structure of HAZV N at 2.7 Å resolution. HAZV N was expressed as an N-terminal glutathione S-transferase (GST) fusion protein then purified using glutathione affinity chromatography followed by ion-exchange chromatography. HAZV N crystallised in the P212121 space group with unit cell parameters a = 64.99, b = 76.10, and c = 449.28 Å. HAZV N consists of a globular domain formed mostly of alpha helices derived from both the N- and C-termini, and an arm domain comprising two long alpha helices. HAZV N has a similar overall structure to CCHFV N, with their globular domains superposing with an RMSD = 0.70 Å, over 368 alpha carbons that share 59 % sequence identity. Four HAZV N monomers crystallised in the asymmetric unit, and their head-to-tail assembly reveals a potential interaction site between monomers. Conclusions: The crystal structure of HAZV N reveals a close similarity to CCHFV N, supporting the use of HAZV as a model for CCHFV. Structural similarity between the N proteins should facilitate study of the CCHFV and HAZV replication cycles without the necessity of working under containment level 4 (CL-4) conditions