Discovery of orbital ordering in Bi2Sr2CaCu2O8+x.

The primordial ingredient of cuprate superconductivity is the CuO2 unit cell. Theories usually concentrate on the intra-atom Coulombic interactions dominating the 3d9 and 3d10 configurations of each copper ion. However, if Coulombic interactions also occur between electrons of the 2p6 orbitals of each planar oxygen atom, spontaneous orbital ordering may split their energy levels. This long-predicted intra-unit-cell symmetry breaking should generate an orbitally ordered phase, for which the charge transfer energy ε separating the 2p6 and 3d10 orbitals is distinct for the two oxygen atoms. Here we introduce sublattice-resolved ε(r) imaging to CuO2 studies and discover intra-unit-cell rotational symmetry breaking of ε(r). Spatially, this state is arranged in disordered Ising domains of orthogonally oriented orbital order bounded by dopant ions, and within whose domain walls low-energy electronic quadrupolar two-level systems occur. Overall, these data reveal a Q = 0 orbitally ordered state that splits the oxygen energy levels by ~50 meV, in underdoped CuO2.

Identification of a nematic pair density wave state in Bi2Sr2CaCu2O8+x.

Electron-pair density wave (PDW) states are now an intense focus of research in the field of cuprate correlated superconductivity. PDWs exhibit periodically modulating superconductive electron pairing that can be visualized directly using scanned Josephson tunneling microscopy (SJTM). Although from theory, intertwining the d-wave superconducting (DSC) and PDW order parameters allows a plethora of global electron-pair orders to appear, which one actually occurs in the various cuprates is unknown. Here, we use SJTM to visualize the interplay of PDW and DSC states in Bi2Sr2CaCu2O8+x at a carrier density where the charge density wave modulations are virtually nonexistent. Simultaneous visualization of their amplitudes reveals that the intertwined PDW and DSC are mutually attractive states. Then, by separately imaging the electron-pair density modulations of the two orthogonal PDWs, we discover a robust nematic PDW state. Its spatial arrangement entails Ising domains of opposite nematicity, each consisting primarily of unidirectional and lattice commensurate electron-pair density modulations. Further, we demonstrate by direct imaging that the scattering resonances identifying Zn impurity atom sites occur predominantly within boundaries between these domains. This implies that the nematic PDW state is pinned by Zn atoms, as was recently proposed [Lozano et al., Phys. Rev. B 103, L020502 (2021)]. Taken in combination, these data indicate that the PDW in Bi2Sr2CaCu2O8+x is a vestigial nematic pair density wave state [Agterberg et al. Phys. Rev. B 91, 054502 (2015); Wardh and Granath arXiv:2203.08250].

Abdomino-endoscopic perineal excision of the rectum for benign and malignant pathology: Technique considerations for true transperineal verus transanal total mesorectal excision endoscopic proctectomy.

PURPOSE: Transanal minimally invasive surgery using single port instrumentation is now well described for the performance of total mesorectal excision with restorative colorectal/anal anastomosis most-often in conjunction with transabdominal multiport assistance. While non-restorative abdomino-endoscopic perineal excision of the anorectum is conceptually similar, it has been less detailed in the literature. METHODS: Consecutive patients undergoing non-restorative ano-proctectomy including a transperineal endoscopic component were analysed. All cases commenced laparoscopically with initial medial to lateral mobilisation of any left colon and upper rectum. The lower anorectal dissection started via an intersphincteric or extrasphincteric incision for benign and malignant pathology, respectively, and following suture closure and circumferential mobilisation of the anorectum, a single port (GelPOINT Path, Applied Medical) was positioned allowing the procedure progress endoscopically in all quadrants up to the cephalad dissection level. Standard laparoscopic instrumentation was used. Specimens were removed perineally. RESULTS: Of the 13 patients (median age 55 years, median BMI 28.75 kg/m2, median follow-up 17 months, 6 males), ten needed completion proctectomy for ulcerative colitis following prior total colectomy (three with concomitant parastomal hernia repair) while three required abdominoperineal resection for locally advanced rectal cancer following neoadjuvant chemoradiotherapy. Median operative time was 190 min, median post-operative discharge day was 7. Eleven specimens were of high quality. Four patients developed perineal wound complications (one chronic sinus, two abscesses needing drainage) within median 17-month follow-up. CONCLUSION: Convergence of transabdominal and transanal technology and technique allows accuracy in combination operative performance. Nuanced appreciation of transperineal operative access should allow specified standardisation and innovation.

Prediction of low pulse oxygen saturation in COVID-19 using remote monitoring post hospital discharge.

BACKGROUND: Monitoring systems have been developed during the COVID-19 pandemic enabling clinicians to remotely monitor physiological measures including pulse oxygen saturation (SpO2), heart rate (HR), and breathlessness in patients after discharge from hospital. These data may be leveraged to understand how symptoms vary over time in COVID-19 patients. There is also potential to use remote monitoring systems to predict clinical deterioration allowing early identification of patients in need of intervention. METHODS: A remote monitoring system was used to monitor 209 patients diagnosed with COVID-19 in the period following hospital discharge. This system consisted of a patient-facing app paired with a Bluetooth-enabled pulse oximeter (measuring SpO2 and HR) linked to a secure portal where data were available for clinical review. Breathlessness score was entered manually to the app. Clinical teams were alerted automatically when SpO2 < 94 %. In this study, data recorded during the initial ten days of monitoring were retrospectively examined, and a random forest model was developed to predict SpO2 < 94 % on a given day using SpO2 and HR data from the two previous days and day of discharge. RESULTS: Over the 10-day monitoring period, mean SpO2 and HR increased significantly, while breathlessness decreased. The coefficient of variation in SpO2, HR and breathlessness also decreased over the monitoring period. The model predicted SpO2 alerts (SpO2 < 94 %) with a mean cross-validated. sensitivity of 66 ± 18.57 %, specificity of 88.31 ± 10.97 % and area under the receiver operating characteristic of 0.80 ± 0.11. Patient age and sex were not significantly associated with the occurrence of asymptomatic SpO2 alerts. CONCLUSION: Results indicate that SpO2 alerts (SpO2 < 94 %) on a given day can be predicted using SpO2 and heart rate data captured on the two preceding days via remote monitoring. The methods presented may help early identification of patients with COVID-19 at risk of clinical deterioration using remote monitoring.

Impact of alcohol & smoking on the surgical management of gastrointestinal patients.

Alcohol and smoking are repeatedly described as modifiable risk factors in clinical studies across all surgical specialities. These lifestyle choices impart a sub-optimal physiology via multiple processes and play an important role in the surgical management of the gastrointestinal patient. Cessation is imperative to optimise the patient's fitness for surgery with surgery itself being a prime opportunity for sustained cessation. A consistent, planned and integrated management involving surgical, anaesthetic, medical, and primary care facets will aid in successful cessation and perioperative care. This review highlights the pathological processes which contribute to perioperative complications and details the current practices to detect, predict and appropriately manage the perioperative gastrointestinal patient who smokes and consumes alcohol.