Development of the British Antarctic Survey Rapid Access Isotope Drill

The British Antarctic Survey Rapid Access Isotope Drill is an innovative new class of electromechanical ice drill, which has recently been used to drill the deepest dry hole drilled by an electromechanical auger drill. The record-breaking depth of 461.58 m was drilled in just over 104 hours at Little Dome C. The drill collects ice chippings, for water stable isotope analysis, rather than an ice core. By not collecting a core the winch can be geared for speed rather than core breaking and is lightweight. Furthermore, emptying of the chippings is performed by simply reversing the drill motor on the surface reducing the overall drilling time significantly. The borehole is then available for instrumentation. We describe the drill in its current state including modifications carried out since it was last deployed. Test seasons and the lessons learned from each are outlined. Finally, future developments for this class of drill are discussed

Integrin Clustering Is Driven by Mechanical Resistance from the Glycocalyx and the Substrate

Integrins have emerged as key sensory molecules that translate chemical and physical cues from the extracellular matrix (ECM) into biochemical signals that regulate cell behavior. Integrins function by clustering into adhesion plaques, but the molecular mechanisms that drive integrin clustering in response to interaction with the ECM remain unclear. To explore how deformations in the cell-ECM interface influence integrin clustering, we developed a spatial-temporal simulation that integrates the micro-mechanics of the cell, glycocalyx, and ECM with a simple chemical model of integrin activation and ligand interaction. Due to mechanical coupling, we find that integrin-ligand interactions are highly cooperative, and this cooperativity is sufficient to drive integrin clustering even in the absence of cytoskeletal crosslinking or homotypic integrin-integrin interactions. The glycocalyx largely mediates this cooperativity and hence may be a key regulator of integrin function. Remarkably, integrin clustering in the model is naturally responsive to the chemical and physical properties of the ECM, including ligand density, matrix rigidity, and the chemical affinity of ligand for receptor. Consistent with experimental observations, we find that integrin clustering is robust on rigid substrates with high ligand density, but is impaired on substrates that are highly compliant or have low ligand density. We thus demonstrate how integrins themselves could function as sensory molecules that begin sensing matrix properties even before large multi-molecular adhesion complexes are assembled

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Stabilizing Mountains, Numinous Rivers: Reclusive Shanshui at the Song Court

This paper examines symbols of the theme of reclusion found in Song dynasty (960-1279) landscape painting produced at the imperial court in order to better understand the breadth, functions, and origins of these symbols. It undertakes a broad survey of extant works from the prolific period of landscape painting production in order to propose the notion of a visual lexicon of reclusive symbolism in Song art history as a means of better understanding these works’ emphasis on the experience of reclusion. In doing so, this paper also provides an alternative framework to that which is often employed by modern scholarship on the Song period, which often focuses on the political and social meanings imbued in landscape paintings

Morel-Lavallée Lesion Following a Low-speed Injury: A Case Report

Introduction: Soft tissue injuries are a common presenting complaint seen in the emergency department following trauma. However, internal degloving injuries are not commonly seen by the emergency provider.Case Report: A 57-year-old male presented with right lower extremity pain, bruising, and swelling after a low-speed bicycle accident five days prior. Physical examination revealed an edematous and ecchymotic right lower extremity extending from the mid-thigh distally. Computed tomography of the thigh demonstrated a hyperdense foci within the fluid collection suggesting internal hemorrhage and internal de-gloving suggestive of a Morel-Lavallée lesion.Discussion: The Morel-Lavallée lesion is a post-traumatic soft tissue injury that occurs as a result of shearing forces that create a potential space for the collection of blood, lymph, and fat. First described in 1853 by French physician Maurice Morel-Lavallée, this internal degloving injury can serve as a nidus of infection if not treated appropriately. Magnetic resonance imaging has become the diagnostic modality of choice due to its high resolution of soft tissue injuries. Treatment has been focused on either conservative management or surgical debridement after consultation with a surgeon.Conclusion: The emergency physician should consider Morel-Lavallée lesions in patients with a traumatic hematoma formation to avoid complications that come from delayed diagnosis

A low resource subglacial bedrock sampler: The percussive rapid access isotope drill (P-RAID)

The paleoclimate community has an interest in distributed subglacial bedrock sampling but, while capable drill systems do exist, they are often incompatible with Twin Otter logistics. To address this issue, a design built on the existing low footprint ice-sampler, the Rapid Access Isotope Drill (RAID) is investigated. The new device will retain key features of the parent system, but the ice drilling elements of the RAID will be replaced by a self-contained rotary-percussive core-drill capable of penetrating ice-consolidated and rocky terrain at and below the ice/rock interface. This new front-end will only be deployed once the interface itself has been attained, providing a pristine core sample from the underlying terrain. The proposed Percussive Rapid Access Isotope Drill (P-RAID) has been inspired by planetary drilling technologies to allow autonomous operations at the bottom of the hole. This paper details the development and testing of the proof-of-concept hardware. The mechanical and electrical design challenges encountered, and the results obtained from a series of prolonged cold chamber tests will be discussed, alongside lessons learned from initial testing in Antarctica

A new percussion hammer mechanism for a borehole deployable subglacial sediment corer

Subglacial sediments have the potential to reveal information about the controls on glacier flow, changes in ice-sheet history and characterise life in those environments. Retrieving sediments from beneath the ice, through hot water drilled access holes at remote field locations, present many challenges. Motivated by the need to minimise weight, corer diameter and simplify assembly and operation, British Antarctic Survey, in collaboration with UWITEC, developed a simple mechanical percussion corer. At depths over 1000 m however, manual operation of the percussion hammer is compromised by the lack of clear operator feedback at the surface. To address this, we present a new auto-release-recovery percussion hammer mechanism that makes coring operations depth independent and improves hammer efficiency. Using a single rope tether for both the corer and hammer operation, this modified percussion corer is relatively simple to operate, easy to maintain, and has successfully operated at a depth of >2130 m