Doubly robust estimation under covariate-induced dependent left truncation.

In prevalent cohort studies with follow-up, the time-to-event outcome is subject to left truncation leading to selection bias. For estimation of the distribution of the time to event, conventional methods adjusting for left truncation tend to rely on the quasi-independence assumption that the truncation time and the event time are independent on the observed region. This assumption is violated when there is dependence between the truncation time and the event time, possibly induced by measured covariates.

Structural cumulative survival models for estimation of treatment effects accounting for treatment switching in randomized experiments.

Treatment switching in a randomized controlled trial occurs when a patient in one treatment arm switches to another arm during follow-up. This can occur at the point of disease progression, whereby patients in the control arm may be offered the experimental treatment. It is widely known that failure to account for treatment switching can seriously bias the estimated treatment causal effect.

Physiological effects and subjective tolerability of prone positioning in COVID-19 and healthy hypoxic challenge.

Background: Prone positioning has a beneficial role in coronavirus disease 2019 (COVID-19) patients receiving ventilation but lacks evidence in awake non-ventilated patients, with most studies being retrospective, lacking control populations and information on subjective tolerability.

Methods: We conducted a prospective, single-centre study of prone positioning in awake non-ventilated patients with COVID-19 and non-COVID-19 pneumonia. The primary outcome was change in peripheral oxygenation in prone supine position.

Endovascular treatment of a large iatrogenic popliteal arteriovenous fistula.

A 40-year-old man presented with years of progressive leg swelling and venous varicosities. Lower limb computed tomography angiography and subsequent digital subtraction angiography demonstrated a large popliteal arteriovenous fistula (AVF). This was treated successfully by endovascular technique with a Viabahn stent (W.

Continuous local anaesthetic wound infusion for postoperative pain after midline laparotomy for colorectal resection in adults.

Background: Colorectal resection through a midline laparotomy is a commonly performed surgical procedure to treat various bowel conditions. The typical postoperative hospital stay after this operation is 6 to 10 days. The main factors hindering early recovery and discharge are thought to include postoperative pain and delayed return of bowel function.

Two-stage residual inclusion for survival data and competing risks-An instrumental variable approach with application to SEER-Medicare linked data.

Instrumental variable is an essential tool for addressing unmeasured confounding in observational studies. Two-stage predictor substitution (2SPS) estimator and two-stage residual inclusion (2SRI) are two commonly used approaches in applying instrumental variables. Recently, 2SPS was studied under the additive hazards model in the presence of competing risks of time-to-events data, where linearity was assumed for the relationship between the treatment and the instrument variable.

Abdominal Aortic Aneurysm Screening: A Systematic Review and Meta-analysis of Efficacy and Cost.

Background: Abdominal aortic aneurysms (AAA) can cause significant mortality when ruptured but are often undiagnosed before this time. Population screening of high-risk individuals and early intervention may mitigate AAA-related mortality. Large trials have demonstrated a mortality benefit for AAA screening, but adoption is not ubiquitous.

Circadian and Brain State Modulation of Network Hyperexcitability in Alzheimer's Disease.

Network hyperexcitability is a feature of Alzheimer' disease (AD) as well as numerous transgenic mouse models of AD. While hyperexcitability in AD patients and AD animal models share certain features, the mechanistic overlap remains to be established. We aimed to identify features of network hyperexcitability in AD models that can be related to epileptiform activity signatures in AD patients.

Single cell heterogeneity: why unstable genomes are incompatible with average profiles.

Multi-level heterogeneity is a fundamental but underappreciated feature of cancer. Most technical and analytical methods either completely ignore heterogeneity or do not fully account for it, as heterogeneity has been considered noise that needs to be eliminated. We have used single-cell and population-based assays to describe an instability-mediated mechanism where genome heterogeneity drastically affects cell growth and cannot be accurately measured using conventional averages.

Ultrathin gold nanowire-functionalized carbon nanotubes for hybrid molecular sensing.

Carbon nanotubes (CNTs) have shown great potential as sensing component in the electrochemical field effect transistor and optical sensors, because of their extraordinary one-dimensional electronic structure, thermal conductivity, and tunable and stable near-infrared emission. However, the insolubility of CNTs due to strong van der Waals interactions limits their use in the field of nanotechnology. In this study, we demonstrate that noncovalent ultrathin gold nanowires functionalized multiwalled carbon nanotube (GNW-CNT) hybrid sensing agents show highly efficient and selective immune molecular sensing in electrochemical and near-infrared photoacoustic imaging methods.

Highly sensitive and selective colorimetric genotyping of single-nucleotide polymorphisms based on enzyme-amplified ligation on magnetic beads.

Herein we report a new strategy for highly sensitive and selective colorimatric assay for genotyping of single-nucleotide polymorphisms (SNPs). It is based on the use of a specific gap ligation reaction, horseradish peroxidase (HRP) for signal amplification, and magnetic beads for the easy separation of the ligated product. Briefly, oligonucleotide capture probe functionalized magnetic beads are first hybridized to a target DNA.