A Vernier ring-oscillator-based time-to-digital converter (TDC) with a new prelogic is presented. Experimental results show that the proposed architecture achieve a 5.5 ps RMS timing jitter with a ...5.1 ps LSB within an area of $0.00151\,{\rm mm}^2$0.00151mm2. Thanks to the new prelogic circuit, the power consumption of the circuit was optimised to $22\,{\rm \mu }{\rm W}$22μW at a rate of 1 Mevents/s for a dynamic range of 4 ns. The area, timing jitter and power consumption make the TDC suitable for an array of electronic readout in a position emission tomography single photon avalanche diode based detectors.
The properties of a phase with large correlation length can be strongly influenced by the underlying normal phase. We illustrate this by studying the half-filled two-dimensional Hubbard model using ...cellular dynamical mean-field theory with continuous-time quantum Monte Carlo. Sharp crossovers in the mechanism that favors antiferromagnetic correlations and in the corresponding local density of states are observed. These crossovers occur at values of the interaction strength U and temperature T that are controlled by the underlying normal-state Mott transition.
Since its experimental discovery, many phenomenological theories successfully reproduced the rapid rise of the Hall number nH, going from p at low doping to 1+p at the critical doping p* of the ...pseudogap in superconducting cuprates. Further comparison with experiments is now needed in order to narrow down candidates. In this paper, we consider three previously successful phenomenological theories in a unified formalism-an antiferromagnetic mean field (AF), a spiral incommensurate antiferromagnetic mean field (sAF), and the Yang-Rice-Zhang (YRZ) theory. We find a rapid rise in the specific heat and a rapid drop in the Seebeck coefficient for increasing doping across the transition in each of those models. The predicted rises and drops are locked, not to p*, but to the doping where antinodal electron pockets, characteristic of each model, appear at the Fermi surface shortly before p*. While such electron pockets are still to be found in experiments, we discuss how they could provide distinctive signatures for each model. We also show that the range of doping where those electron pockets would be found is strongly affected by the position of the van Hove singularity.
Defect-induced magnetic moments are at the center of the research effort on spintronic applications of graphene. Here, we study the problem of a nonmagnetic impurity in graphene with a new ...theoretical method, inhomogeneous cluster dynamical mean-field theory (I-CDMFT), which takes into account interaction-induced short-range correlations while allowing long-range inhomogeneities. The system is described by a Hubbard model on the honeycomb lattice. The impurity is modeled by a local potential. For a large enough potential, interactions induce local antiferromagnetic correlations around the impurity and a net total spin 1/2 appears, in agreement with Lieb's theorem. Bound states caused by the impurity are visible in the local density of states (LDOS) and have their energies shifted by interactions in a spin-dependent way, leading to the antiferromagnetic correlations. Our results take into account dynamical correlations; nevertheless they qualitatively agree with previous mean-field and density functional theory (DFT) studies. Moreover, they provide a relation between impurity potential and on-site repulsion U that could in principle be used to determine experimentally the value of U.
Background
Symptoms of bowel dysfunction after sphincter-preserving rectal cancer surgery have an important impact on health-related quality of life (HRQOL), but that relationship is complex. A ...better understanding of this relationship allows for better informed shared decision-making about surgery. Our objective was to perform a systematic review to determine which HRQOL domains are most affected by postoperative bowel dysfunction.
Methods
A systematic review of the CINAHL, Cochrane Library, Embase, Medline, PsycInfo, PubMed, Web of Science, and Scopus databases was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We included studies that evaluated bowel function after sphincter-preserving rectal cancer surgery and assessed HRQOL using a validated instrument. The quality of HRQOL analysis was assessed using an 11-item checklist. The main outcome was the impact bowel dysfunction had on global and domain specific quality-of-life indices. The impact was evaluated for clinical relevance using the Minimum Clinical Important Difference (MCID) for each specific HRQOL instrument.
Results
Out of 952 unique citations, 103 studies were full-text reviews. Eighteen studies met the inclusion criteria (4 prospective cohorts and 9 cross-sectional studies). Of the 15 studies with long-term follow-up, the time to assessment after surgery ranged from 1.2 to 14.6 years. The low anterior resection syndrome score and European Organization for Research and Treatment core quality-of-life questionnaire (EORTC QLQ-C30) were the most commonly used instruments. Medium and large magnitudes in MCID were seen for global health, social functioning, emotional functioning, fatigue, diarrhea, and financial difficulties. Among included studies, the most consistently reported functional domains affected by bowel function were social functioning and emotional functioning.
Conclusions
Following sphincter-preserving rectal cancer surgery, poor bowel function mainly affects the social and emotional functional domains of HRQOL, which in turn impact global scores. This finding can help inform patients about expected changes in HRQOL after rectal cancer surgery and facilitate individualized treatment decisions.
Summary
We measured the distance 112 patients walked in 6 min, as well as their peak oxygen consumption pedalling a bicycle, week before scheduled resection of benign or malignant colorectal disease. ...The distance walked correlated with peak oxygen consumption, the former ‘accounting’ for about half the variation in the latter, r2 0.52 (95% CI 0.38–0.64), p < 0.0001. In the first postoperative month, 42/112 patients experienced a complication. In multivariate analysis, complications were less likely with longer walking distances and increasing age: the odds ratio (95% CI) reduced to 0.995 (0.990–0.999) for each metre distance, and to 0.96 (0.93–0.99) with each year of age, p = 0.025 and p = 0.018, respectively. The distance walked in 6 min before surgery can provide prognostic information when cardiopulmonary exercise testing is unavailable.
This article is accompanied by an Editorial by Carlisle, pp 799–803 of this issue.
Background
Extended thromboprophylaxis after abdominal and pelvic cancer surgery to prevent venous thromboembolic events (VTE) is recommended but adherence is sub-optimal. Identifying patients at ...highest risk for post-discharge events may allow for selective extended thromboprophylaxis. The aim of our study was to identify the different risk factors of venous thromboembolism for in-hospital and post-discharge events.
Methods
The American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) 2012–2016 database was queried for all patients having colorectal resection. Primary outcome was postoperative VTE occurrence within 30 days. A multinomial logistic regression was performed to identify in-hospital and post-discharge predictors of VTE, adjusting for potential confounders.
Results
Out of 260,258 patients, 5381 (2.1%) developed VTE. A total of 3442 (1.3%) were diagnosed during the initial hospital stay and 1929 (0.8%) post-discharge. Risk factors for in-hospital and post-discharge VTE were different as patients with an in-hospital event were more likely to be older, male, known for preoperative steroid use, have poor functional status, significant weight loss, preoperative sepsis, prolonged operative time, undergoing an emergency operation. In the post-discharge setting, steroid use, poor functional status, preoperative sepsis, and postoperative complications remained significant. Postoperative complications were the strongest predictor of in-hospital and post-discharge VTE. Patients with inflammatory bowel disease had a higher risk of VTE than patients with malignancy for both in-patient and post-discharge events.
Conclusions
Patients at high-risk for post-discharge events have different characteristics than those who develop VTE in-hospital. Identifying this specific subset of patients at highest risk for post-discharge VTE may allow for the selective use of prolonged thromboprophylaxis.
Hole electrical transport in a p-doped nanochannel defined between two L-shape etched trenches made on a silicon-on-insulator substrate is investigated using a TCAD-Medici simulator. We study the ...impact of the etched trenches' geometry and dielectric filling materials on the current-voltage characteristics of the device. Carrier accumulation on frontiers defined by the trenches causes a modulation of the hole density inside the conduction channel as the bias voltage varies and this gives rise to a diode-like characteristic. For a 1.2 µm-long channel, plots of the electric field distribution show that a nonlinear transport regime is reached at a moderate reverse and forward bias of ± 2 V. Plots of the carrier velocity along the conduction channel show that holes remain hot for a few hundreds of nm outside the nanometre-wide channel, at a bias of ± 10 V. Filling the etched trenches with a high-κ dielectric material gives rise to a lower threshold voltage, V(th). A similar decrease of V(th) is also achieved by reducing the longitudinal and/or the transverse trench width. Our simulation results provide useful design guidelines for future integrated self-switching-diode-based circuits.
Recent quantum-gas microscopy of ultracold atoms and scanning tunneling microscopy of the cuprates reveal new detailed information about doped Mott antiferromagnets, which can be compared with ...calculations. Using cellular dynamical mean-field theory, we map out the antiferromagnetic (AF) phase of the two-dimensional Hubbard model as a function of interaction strength U, hole doping δ, and temperature T. The Néel phase boundary is nonmonotonic as a function of U and δ. Frustration induced by second-neighbor hopping reduces Néel order more effectively at small U. The doped AF is stabilized at large U by kinetic energy and at small U by potential energy. The transition between the AF insulator and the doped metallic AF is continuous. At large U, we find in-gap states similar to those observed in scanning tunneling microscopy. We predict that, contrary to the Hubbard bands, these states are only slightly spin polarized.
Background
Restorative proctectomy for rectal cancer is associated with a high incidence of low anterior resection syndrome (LARS), but few studies report longitudinal results for bowel function. The ...aim of our study was to examine the trajectory of change of LARS over the first 18 months after restorative proctectomy for rectal cancer.
Methods
A prospective database measuring functional outcomes in rectal cancer patients from a single university-affiliated specialist colorectal referral center from 10/2018 to 03/2020 was queried. Patients were included in this study if they underwent restorative proctectomy for rectal cancer and had at least three assessments in the first 18 months after primary surgery or after closure of proximal diversion. Bowel function was assessed using the LARS score, administered at every surveillance follow-up after restoration of bowel continuity. Latent-class growth curve (trajectory) analysis was used to identify different trajectories of LARS changes over the first 18 months and group patients into these trajectory groups. These groups were then compared to identify predictors for each trajectory.
Results
A total of 95 patients were included (63 males, mean age. 61.3 ± 12.5 years). Trajectory analysis identified three distinct trajectory groups. Group 1 had stable minimal LARS over time (26%). Group 2 had early LARS scores consistent with the minor LARS category and improved with time (28%). Group 3 had persistently high LARS scores (45%). Neoadjuvant therapy, intersphincteric resection, and proximal diversion were more common in group 3.
Conclusions
We identified three main trajectories of change of LARS in the 18 months after restorative proctectomy. These data may be used to better inform patients of their expected postoperative bowel function.
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