The 5.2 ka climate event: Evidence from stable isotope and multi-proxy palaeoecological peatland records in Ireland

AbstractEvidence for a major climate event at 5.2 ka has been reported globally and is associated with considerable societal disruption, but is poorly characterised in northwest Europe. This event forms part of a broader period of re-organisation in the Earth's ocean-atmosphere circulation system between 6 and 5 ka. This study tests the nature and timing of the event in northwest Europe, a region highly sensitive to change in meridional overturning circulation and mid-latitude westerly airflow. Here we report three high-resolution Irish multi-proxy records obtained from ombrotrophic peatlands that have robust chronological frameworks. We identify the 5.2 ka event by a sustained decrease in δ18Ocellulose at all three sites, with additional and parallel changes in δ13Ccellulose and palaeoecological (testate amoebae, plant macrofossil and humification) data from two sites in northern Ireland. Data from Sluggan Moss demonstrate a particularly coherent shift towards wetter conditions. These data support the hypothesis that the event was caused by a prolonged period of positive North Atlantic Oscillation conditions, resulting in pervasive cyclonic weather patterns across northwest Europe, increasing precipitation over Ireland

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

Elastic tissues in adenoid cystic carcinomas

Ten adenoid cystic carcinomas were examined for elastic tissues. The principal stain used was a Verhoeff's hematoxylin, alcian blue, chlorantine fast red sequence. Eight of the lesions contained detectable amounts of elastic tissue and, of these, six contained relatively dense and extensive deposits. The elastic tissue occurs principally in linear and radial arrangements immediately adjacent to the islands of neoplastic cells. Small quantities were seen in spheres within the neoplastic islands. The background in which the elastic tissue formed was alcian blue positive and chlorantine fast red negative. Both epithelial and myoepithelial cells are present in these neoplasms, and the evidence supports the view that one or both of these is directly involved in the production of elastic tissues in adenoid cystic carcinomas. It would be reasonable to suspect that the myoepithelial cells may have this property, but the present study neither confirms nor denies this hypothesis

Lipid and protein histochemistry of enamel - Effects of fluoride

Staining reactions for a number of histochemical procedures for lipophilic staining and protein were studied in the enamel matrix along the length of rat incisors. Sudan Black gave a positive stain across the whole thickness of very early enamel (up to 30 μm) but this staining only continued as a narrow band close to the ameloblasts as the enamel matured. A variety of tests for protein produced almost identical staining patterns in enamel matrix up to 100 μm thick. Since the pattern of "lipid" staining persisted, after using a number of procedures which could normally be expected to remove lipid, it is suggested that Sudan Black positive staining may be due to lipophilic protein rather than lipid itself. Fluoride did not significantly alter the staining reactions for "lipid" and protein but did proceduce matrix which was much more effectively stained by cross-linking agents FFDNB and FF sulphene

Focal palmoplantar and gingival hyperkeratosis syndrome: Report of a family, with cytologic, ultrastructural, and histochemical findings

An Australian family in which two members were affected by focal palmoplantar and gingival mucosal hyperkeratosis syndrome is reported. The propositus and his daughter had symptoms which suggested that esophageal lesions might be present. In view of the association of tylosis with esophageal carcinoma in other families, both patients were investigated by barium swallow or endoscopy. No esophageal lesions were found. Previously unreported paranuclear bodies were described in the keratinocytes of the spinous and granular cell layers of the finely papillated gingival epithelium of the propositus. Similar paranuclear bodies, although rare, were identified in cytologic smears from the four members of the family examined, two of whom had slight whitening of the mucosa of the retromolar pads only. By electron microscopy and histochemistry, these bodies were characterized as condensations of tonofilaments and not heteromorphic keratohyalin

Tooth enamel structure in the koala, Phascolarctos cinereus: some functional interpretations.

The purpose of this study is to determine whether the structural organization of Pattern 2 marsupial enamel in the Koala is disposed to resist wear on the sectorial crests of the molar teeth. The orientation of wear on the crests is uniformly delineated by parallel scratches on their polished surfaces. Twin blades, a leading and a trailing edge of enamel are formed on each crest by wear into dentine on which the differential wear at enamel to dentine interfaces indicates that the direction of wear is labial to lingual. 96 leading and trailing edges from 12 koala molars were examined by light and scanning electron microscopy as ground sections, polished and etched surfaces or polished and etched whole mount preparations sputter coated with gold. The results showed that the leading and trailing enamel edges are different in their thicknesses, and in the course of their rods. The rods in the thinner leading edge are angled at 25 degrees to the long axis of the tooth and cross the worn surface at 60-70 degrees. Trailing rods run at 5 degrees to the long axis to cross the worn surface at 90 degrees. The inter-rod sheets run parallel to the wear striations and thus hold the rods in palisades angled in the leading edge particularly to resist the vector of the occlusal forces in the direction of wear. Crystals in the rods emerge roughly perpendicular onto the worn surface which makes them more resistant to abrasion than those in the inter-rod substance which lie parallel to the worn surface and are more readily removed. Koala enamel on the sectorial crests is thus a simple Pattern 2 rod packing pattern but the angles of the rods and the alignment of the inter-rod substance appear to be adapted to resist occlusal forces and abrasion

Differences in fluoride levels in the blood between sheep, rabbit and rat

The various techniques for measuring F levels in serum with the fluoride electrode were compared to select a suitable procedure for monitoring F in the sera of animals after the administration of an insult dose of fluoride. F was present in the sera in two forms-ionic and bound. In the the sera of sheep and rabbit, the bound F was released by diffusion with, e.g. HClO4 but in rat sera was only released by ashing before diffusion