Reflectance anisotropy spectroscopy of magnetite (110) surfaces

Reflectance anisotropy spectroscopy (RAS) has been used to measure the optical anisotropies of bulk and thin-film Fe3O4(110) surfaces. The spectra indicate that small shifts in energy of the optical transitions, associated with anisotropic strain or electric field gradients caused by the (110) surface termination or a native oxide layer, are responsible for the strong signal observed. The RAS response was then measured as a function of temperature. A distinct change in the RAS line-shape amplitude was observed in the spectral range from 0.8 to 1.6 eV for temperatures below the Verwey transition of the crystal. Finally, thin-film magnetite was grown by molecular beam epitaxy on MgO(110) substrates. Changes in the RAS spectra were found for different film thickness, suggesting that RAS can be used to monitor the growth of magnetite (110) films in situ. The thickness dependence of the RAS is discussed in terms of various models for the origin of the RAS signal

Scalable, ultra-resistant structural colors based on network metamaterials

Structural colors have drawn wide attention for their potential as a future printing technology for various applications, ranging from biomimetic tissues to adaptive camouflage materials. However, an efficient approach to realize robust colors with a scalable fabrication technique is still lacking, hampering the realization of practical applications with this platform. Here, we develop a new approach based on large-scale network metamaterials that combine dealloyed subwavelength structures at the nanoscale with lossless, ultra-thin dielectric coatings. By using theory and experiments, we show how subwavelength dielectric coatings control a mechanism of resonant light coupling with epsilon-near-zero regions generated in the metallic network, generating the formation of saturated structural colors that cover a wide portion of the spectrum. Ellipsometry measurements support the efficient observation of these colors, even at angles of 70°. The network-like architecture of these nanomaterials allows for high mechanical resistance, which is quantified in a series of nano-scratch tests. With such remarkable properties, these metastructures represent a robust design technology for real-world, large-scale commercial applications

Overview of the Lost Meteorites of Antarctica field campaigns

The Lost Meteorites of Antarctica project was the first UK-led Antarctic meteorite recovery expedition. The project has successfully confirmed two new high-density meteorite stranding zones in the Hutchison Icefield and Outer Recovery Icefields areas and investigated the geology of three previously unvisited Antarctic nunataks (Turner Nunatak, Pillinger Nunatak, Halliday Nunatak). The project undertook meteorite searching on the ice surface via skidoo reconnaissance and systematic searching and developed a novel pulse induction metal detection system to search for englacial iron-rich meteorites trapped within the upper one meter of ice. In total, 121 meteorites have been recovered from the ice surface searching activities, which are now curated in the United Kingdom at the Natural History Museum London and are available for scientific analysis

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

General approach to the analysis of plasmonic structures using spectroscopic ellipsometry

In this article a route to analyze the full optical response of plasmonic structures is developed. First, the simple case of an anisotropic thin plasmonic layer supported on a transparent substrate is analyzed by introducing a quantity named anisotropic surface excess function (ASEF). The spectral features are analyzed in terms of effective dielectric function, demonstrating a more direct relation with the plasmonic response of the layer. The formalism is then generalized using a transfer matrix method. The formalism developed is supported by experimental evidence obtained by measuring the response of anisotropic nanoparticle arrays grown at a glancing angle. The agreement between theory and experiment is clear, suggesting that SE can be conveniently employed to measure the spectroscopic response of plasmonic structures. It is also demonstrated that the figure of merit of the plasmonic resonance for refractive index sensing can be greatly improved, with optimized measurement configurations, using polarized spectroscopy

PPH versus THD: a comparison of two techniques for III and IV degree haemorrhoids. Personal experience

The aim of our study was to evaluate, through prospective randomized study, the outcome and the immediate and late complications of the two types of surgery most widely used for degree III-IV haemorrhoids

Ileocecal-colonic intussusception caused by cecal adenocarcinoma A case report.

INTRODUCTION: Intussusception in adults is an infrequent cause of intestinal occlusion that is usually due to neoplasm lesions. The unspecific nature of the clinical presentation often delays diagnosis. It is most commonly emergency explorative laparotomy which clarifies the etiology of the occlusion. The authors report a case of intestinal occlusion caused by ileocecal-colonic invagination with a small cecal adenocarcinoma as lead point, in a 74-year-old woman. CASE REPORT: A 74-year-old woman came to the Emergency Department, complaining of crampy pain in the mid- and lower abdomen. An abdominal ultrasound revealed a "pseudokidney sign" apparently involving the cecum. Because there were no clear signs of occlusion, the patient was dicharged on the same day. Three days later, upon admission, the patient complained of episodes of abdominal pain with intervals of moderate well-being, associated with nausea, vomiting and an inability to pass stool (but not gas) for 36 hours. On clinical examination her abdomen was distended and tender on palpation in all quadrants, especially in the right iliac fossa where a large mass could be felt. Standard abdominal x-Ray documented gaseous distension of some loops of the jejunum-ileum with some air-fluid level. The patient underwent an abdominal CT scan which showed advanced intussusception that appeared to be ileocolic and multiple enlarged lymphnodes were found in the invaginated mesentery at the base of which there appears to be a thickening of the intestinal wall that is probably neoplastic in nature. The patient underwent explorative laparotomy. Ileocecal-colonic intussusception caused by a cecal growth 5 cm in diameter was found on examination of the surgical specimen. Histology showed that the cause of the large swelling of the ascending colon was a vegetating ulcerated adenocarcinoma (medium grade differentiation: G2), measuring 6.5x 4.0 cm, arising from a tubulovillous adenoma infiltrating the submucosa. CONCLUSIONS: Most cases of intussusception are caused by structural lesions, a large percentage of which are malignant, especially in the colon. In our patient the lead point was a small cecal polyp which, together with the last loop of the ileum and the ileocecal valve, was pulled into the ascending colon. Although most cases of intussusception in adults are diagnosed at the operating table, noninvasive diagnostic tools like ultrasonography and CT scanning are very useful. Treatment in adults is usually surgical and involves en bloc resection of the lesion. Manual reduction of the intussusception is not advisable because of the risk of dissemination if the lead point is malignant