Association between treatment with apixaban, dabigatran, rivaroxaban, or warfarin and the risk of osteoporotic fractures among patients with atrial fibrillation: A population-based cohort study

Background: It is unclear whether anticoagulant type is associated with the risk for osteoporotic fracture, a deleterious complication of anticoagulants among patients with atrial fibrillation (AF). Objective: To compare the risk for osteoporotic fracture between anticoagulants. Design: Population-based cohort study. Setting: Territory-wide electronic health record database of the Hong Kong Hospital Authority. Participants: Patients newly diagnosed with AF between 2010 and 2017 who received a new prescription for warfarin or a direct oral anticoagulant (DOAC) (apixaban, dabigatran, or rivaroxaban). Follow-up ended on 31 December 2018. Measurements: Osteoporotic hip and vertebral fractures in anticoagulant users were compared using propensity score–weighted cumulative incidence differences (CIDs). Results: There were 23 515 patients identified (3241 apixaban users, 6867 dabigatran users, 3866 rivaroxaban users, and 9541 warfarin users). Overall mean age was 74.4 years (SD, 10.8), ranging from 73.1 years (warfarin) to 77.9 years (apixaban). Over a median follow-up of 423 days, 401 fractures were identified (crude event number [weighted rate per 100 patient-years]: apixaban, 53 [0.82]; dabigatran, 95 [0.76]; rivaroxaban, 57 [0.67]; and warfarin, 196 [1.11]). After 24-month follow-up, DOAC use was associated with a lower risk for fracture than warfarin use (apixaban CID, −0.88% [95% CI, −1.66% to −0.21%]; dabigatran CID, −0.81% [CI, −1.34% to −0.23%]; and rivaroxaban CID, −1.13% [CI, −1.67% to −0.53%]). No differences were seen in all head-to-head comparisons between DOACs at 24 months (apixaban vs. dabigatran CID, −0.06% [CI, −0.69% to 0.49%]; rivaroxaban vs. dabigatran CID, −0.32% [CI, −0.84% to 0.18%]; and rivaroxaban vs. apixaban CID, −0.25% [CI, −0.86% to 0.40%]). Limitation: Residual confounding is possible. Conclusion: Among patients with AF, DOAC use may result in a lower risk for osteoporotic fracture compared with warfarin use. Fracture risk does not seem to be altered by the choice of DOAC. These findings may help inform the benefit–risk assessment when choosing between anticoagulants. Primary Funding Source: The University of Hong Kong and University College London Strategic Partnership Fund

A survey of performance enhancement of transmission control protocol (TCP) in wireless ad hoc networks

This Article is provided by the Brunel Open Access Publishing Fund - Copyright @ 2011 Springer OpenTransmission control protocol (TCP), which provides reliable end-to-end data delivery, performs well in traditional wired network environments, while in wireless ad hoc networks, it does not perform well. Compared to wired networks, wireless ad hoc networks have some specific characteristics such as node mobility and a shared medium. Owing to these specific characteristics of wireless ad hoc networks, TCP faces particular problems with, for example, route failure, channel contention and high bit error rates. These factors are responsible for the performance degradation of TCP in wireless ad hoc networks. The research community has produced a wide range of proposals to improve the performance of TCP in wireless ad hoc networks. This article presents a survey of these proposals (approaches). A classification of TCP improvement proposals for wireless ad hoc networks is presented, which makes it easy to compare the proposals falling under the same category. Tables which summarize the approaches for quick overview are provided. Possible directions for further improvements in this area are suggested in the conclusions. The aim of the article is to enable the reader to quickly acquire an overview of the state of TCP in wireless ad hoc networks.This study is partly funded by Kohat University of Science & Technology (KUST), Pakistan, and the Higher Education Commission, Pakistan

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Parameters Estimation for Interference Cancellation in Power-Controlled MC-CDMA Downlink Transmissions

We consider the downlink of a power-controlled MC-CDMA network in which the base station assigns the power to each user according to its location within the cell. In particular, more power is assigned to the users near the cell boundaries in order to improve the geographical fairness in data reception. This results in a near-far effect for the users located close to the base station, which enhances the multiple-access interference (MAI) and limits the performance of conventional single-user receivers. Interference cancellation (IC) schemes may be employed to mitigate the detrimental effects of MAI. However, they require knowledge of the channel responses as well as of the noise power and strengths of the interfering signals. In this paper, we address the problem of estimating all of the above parameters using a maximum likelihood (ML) approach and exploiting pilot blocks multiplexed with the transmitted data. The estimates are then used by a non-linear detector in which an interfering signal is cancelled provided that its estimated power exceeds a given threshold. Simulation results show that the proposed scheme outperforms other existing IC-based techniques

Parameter Estimation for Interference Cancellation in Power-Controlled MC-CDMA Downlink Transmissions

We consider the downlink of a power-controlled MC-CDMA network in which the base station assigns the power to each user according to its location within the cell. In particular, more power is assigned to the users near the cell boundaries in order to improve the geographical fairness in data reception. This results in a near-far effect for the users located close to the base station, which enhances the multiple-access interference (MAI) and limits the performance of conventional single-user receivers. Interference cancellation (IC) schemes may be employed to mitigate the detrimental effects of MAI. However, they require knowledge of the channel responses as well as of the noise power and strengths of the interfering signals. In this paper, we address the problem of estimating all of the above parameters using a maximum likelihood (ML) approach and exploiting pilot blocks multiplexed with the transmitted data. The estimates are then used by a non-linear detector in which an interfering signal is cancelled provided that its estimated power exceeds a given threshold. Simulation results show that the proposed scheme outperforms other existing IC-based techniques