A low-latency graph computer to identify metastable particles at the Large Hadron Collider for real-time analysis of potential dark matter signatures.

Image recognition is a pervasive task in many information-processing environments. We present a solution to a difficult pattern recognition problem that lies at the heart of experimental particle physics. Future experiments with very high-intensity beams will produce a spray of thousands of particles in each beam-target or beam-beam collision. Recognizing the trajectories of these particles as they traverse layers of electronic sensors is a massive image recognition task that has never been accomplished in real time. We present a real-time processing solution that is implemented in a commercial field-programmable gate array using high-level synthesis. It is an unsupervised learning algorithm that uses techniques of graph computing. A prime application is the low-latency analysis of dark-matter signatures involving metastable charged particles that manifest as disappearing tracks.

A UK consensus statement on thromboprophylaxis for autologous breast reconstruction.

Microsurgical breast reconstruction accounts for 22% of breast reconstructions in the UK. Despite thromboprophylaxis, venous thromboembolism (VTE) occurs in up to 4% of cases. Using a Delphi process, this study established a UK consensus on VTE prophylaxis strategy, for patients undergoing autologous breast reconstruction using free-tissue transfer. It captured geographically divergent views, producing a guide that reflected the peer opinion and current evidence base. METHODS: Consensus was ascertained using a structured Delphi process. A specialist from each of the UK's 12 regions was invited to the expert panel. Commitment to three to four rounds of questions was sought at enrollment. Surveys were distributed electronically. An initial qualitative free-text survey was distributed to identify likely lines of consensus and dissensus. Each panelist was provided with full-text versions of key papers on the topic. Initial free-text responses were analyzed to develop a set of structured quantitative statements, which were refined via a second survey as a consensus was approached. RESULTS: The panel comprised 18 specialists: plastic surgeons and thrombosis experts from across the UK. Each specialist completed three rounds of surveys. Together, these plastic surgeons reported having performed more than 570 microsurgical breast reconstructions in the UK in 2019. A consensus was reached on 27 statements, detailing the assessment and delivery of VTE prophylaxis. CONCLUSION: To our knowledge, this is the first study to collate current practice, expert opinion from across the UK, and a literature review. The output was a practical guide for VTE prophylaxis for microsurgical breast reconstruction in any UK microsurgical breast reconstruction unit.

Searching for metastable particles using graph computing.

The reconstruction of charged particle trajectories at the Large Hadron Collider and future colliders relies on energy depositions in sensors placed at distances ranging from a centimeter to a meter from the colliding beams. We propose a method of detecting charged particles that decay invisibly after traversing a short distance of about 25 cm inside the experimental apparatus. One of the decay products may constitute the dark matter known to be 84% of all matter at galactic and cosmological distance scales. Our method uses graph computing to cluster spacepoints recorded by two-dimensional silicon pixel sensors into mathematically-defined patterns. The algorithm may be implemented on silicon-based integrated circuits using field-programmable gate array technology to augment or replace traditional computing platforms.

DIEP breast reconstruction following multiple abdominal liposuction procedures.

OBJECTIVE: Previous abdominal wall surgery is viewed as a contraindication to abdominal free tissue transfer. We present two patients who underwent multiple abdominal liposuction procedures, followed by successful free deep inferior epigastric artery perforator flap. We review the literature pertaining to reliability of abdominal free flaps in those with previous abdominal surgery. METHODS: Review of case notes and radiological investigations of two patients, and a PubMed search using the terms "DIEP", "deep inferior epigastric", "TRAM", "transverse rectus abdominis", "perforator" and "laparotomy", "abdominal wall", "liposuction", "liposculpture", "fat graft", "pfannenstiel", with subsequent appraisal of relevant papers by the first and second authors. RESULTS: Patient 1 had 3 episodes of liposuction from the abdomen for fat grafting to a reconstructed breast. Subsequent revision reconstruction of the same breast with DIEP flap was preceded by CT angiography, which demonstrated normal perforator anatomy. The reconstruction healed well with no ischaemic complications. Patient 2 had 5 liposuction procedures from the abdomen to graft fat to a wide local excision defect. Recurrence of cancer led to mastectomy and immediate reconstruction with free DIEP flap. Preoperative MR angiography demonstrated a large perforator right of the umbilicus, with which the intraoperative findings were consistent. The patient had an uneventful recovery and good healing with no fat necrosis or wound dehiscence. CONCLUSIONS: We demonstrate that DIEP flaps can safely be raised without perfusion-related complications following multiple liposuction procedures to the abdomen. The safe interval between procedures is difficult to quantify, but we demonstrate successful free flap after 16 months.