Neural correlates of performance monitoring in daily and intermittent smokers

OBJECTIVES: Despite efforts that have increased smoking regulation, cigarette taxation, and social stigma, cigarette smoking remains the leading cause of preventable death worldwide, and a significant personal and public economic burden. In the U.S., intermittent smokers comprise approximately 22% of all smokers and represent a stable, non-dependent group that may possess protective factors that prevent the transition to dependence. One possibility is that intermittent smokers have intact CNS frontal regulatory and control mechanisms that enable resistance to nicotine-induced changes. METHODS: The present study measured inhibitory control using a flanker task and a go-nogo continuous performance tasks in daily dependent smokers, intermittent non-dependent smokers, and nonsmokers. Event-related potential (ERP) measures of were concurrently recorded to measure performance monitoring via Event-Related Negativity (ERN) and error positivity (Pe) components during error trials for each task. RESULTS: In both tasks, behavioral and ERN measures did not differ between groups; however, amplitude of the Pe component was largest among intermittent smokers. CONCLUSIONS: Thus, intermittent smokers differed from both daily smokers and nonsmokers on error processing, potentially revealing neuroprotective cognitive processes in nicotine dependence. SIGNIFICANCE: A better understanding of factors that mediate behavioral regulation may provide novel treatment approaches that help individuals achieve controlled smoking or cessation

Dna2 in chromosome stability and cell survival—is it all about replication forks?

The conserved nuclease-helicase DNA2 has been linked to mitochondrial myopathy, Seckel syndrome, and cancer. Across species, the protein is indispensable for cell proliferation. On the molecular level, DNA2 has been implicated in DNA double-strand break (DSB) repair, checkpoint activation, Okazaki fragment processing (OFP), and telomere homeostasis. More recently, a critical contribution of DNA2 to the replication stress response and recovery of stalled DNA replication forks (RFs) has emerged. Here, we review the available functional and phenotypic data and propose that the major cellular defects associated with DNA2 dysfunction, and the links that exist with human disease, can be rationalized through the fundamental importance of DNA2-dependent RF recovery to genome duplication. Being a crucial player at stalled RFs, DNA2 is a promising target for anti-cancer therapy aimed at eliminating cancer cells by replication-stress overload

Strain induced power enhancement of far-UVC LEDs on high temperature annealed AlN templates

High temperature annealed AlN/sapphire templates exhibit a reduced in-plane lattice constant compared to conventional non-annealed AlN/sapphire grown by metalorganic vapor phase epitaxy (MOVPE). This leads to additional lattice mismatch between the template and the AlGaN-based ultraviolet-C light emitting diode (UVC LED) heterostructure grown on these templates. This mismatch introduces additional compressive strain in AlGaN quantum wells resulting in enhanced transverse electric polarization of the quantum well emission at wavelengths below 235 nm compared to layer structures deposited on conventional MOVPE-grown AlN templates, which exhibit mainly transverse magnetic polarized emission. In addition, high temperature annealed AlN/sapphire templates also feature reduced defect densities leading to reduced non-radiative recombination. Based on these two factors, i.e., better outcoupling efficiency of the transverse electric polarized light and an enhanced internal quantum efficiency, the performance characteristic of far-UVC LEDs emitting at 231 nm was further improved with a cw optical output power of 3.5 mW at 150 mA

Low resistance n-contact for UVC LEDs by a two-step plasma etching process

The impact of plasma etching on the formation of low-resistance n-contacts on the AlGaN:Si current spreading layer during the chip fabrication of ultraviolet light-emitting diodes (UV LEDs) emitting at 265 nm is investigated. A two-step plasma etching process with a first rapid etching using BCl3/Cl2 gas mixture and a second slow etching step using pure Cl2 gas has been developed. The etching sequence provides smooth mesa side-walls and an n-AlGaN surface with reduced surface damage. Ohmic n-contacts with a contact resistivity of 3.5 10-4 Ωcm2 are obtained on Si-doped Al0.65Ga0.35N layers and the operating voltages of the UVC LEDs were reduced by 2 V for a current of 20 mA. © 2020 The Author(s). Published by IOP Publishing Ltd

A Novel approach to quality-of-service provisioning in trusted relay quantum key distribution networks

In recent years, noticeable progress has been made in the development of quantum equipment, reflected through the number of successful demonstrations of Quantum Key Distribution (QKD) technology. Although they showcase the great achievements of QKD, many practical difficulties still need to be resolved. Inspired by the significant similarity between mobile ad-hoc networks and QKD technology, we propose a novel quality of service (QoS) model including new metrics for determining the states of public and quantum channels as well as a comprehensive metric of the QKD link. We also propose a novel routing protocol to achieve high-level scalability and minimize consumption of cryptographic keys. Given the limited mobility of nodes in QKD networks, our routing protocol uses the geographical distance and calculated link states to determine the optimal route. It also benefits from a caching mechanism and detection of returning loops to provide effective forwarding while minimizing key consumption and achieving the desired utilization of network links. Simulation results are presented to demonstrate the validity and accuracy of the proposed solutions

Multi-Layer Cyber-Physical Security and Resilience for Smart Grid

The smart grid is a large-scale complex system that integrates communication technologies with the physical layer operation of the energy systems. Security and resilience mechanisms by design are important to provide guarantee operations for the system. This chapter provides a layered perspective of the smart grid security and discusses game and decision theory as a tool to model the interactions among system components and the interaction between attackers and the system. We discuss game-theoretic applications and challenges in the design of cross-layer robust and resilient controller, secure network routing protocol at the data communication and networking layers, and the challenges of the information security at the management layer of the grid. The chapter will discuss the future directions of using game-theoretic tools in addressing multi-layer security issues in the smart grid.Comment: 16 page

Examining the role of menthol cigarettes in progression to established T smoking among youth

Background: Menthol, a flavoring compound added to cigarettes, makes cigarettes more appealing to youth and inexperienced smokers and increases cigarettes\u27 abuse liability. However, limited studies are available on menthol\u27s role in smoking progression. Methods: To assess the association between menthol in cigarettes and progression to established smoking, we used five waves of data from the Evaluation of Public Education Campaign on Teen Tobacco Cohort Study, a nationally representative longitudinal survey of U.S. youth conducted as part of “The Real Cost” evaluation. We used discrete time survival analysis to model the occurrence of two event outcomes—progression to established, current smoking and progression to established, frequent smoking—using a logit model with a menthol use indicator as the key explanatory variable. Based on this framework, we estimated the effect of prior menthol use on the odds of smoking progression. Results: In the progression to established, current smoking model, prior menthol use was significantly associated with progression [adjusted odds ratio (aOR) = 1.80, p \u3c .05, confidence interval (CI) = (1.03–3.16)]. While results were in a similar direction for the model of progression to established, frequent smoking, the association between prior menthol use and this progression model did not reach significance [aOR=1.56, CI = (0.80–3.03)]. Conclusion: The results suggest a relationship between using menthol cigarettes and progression from experi- mental to established, current smoking among youth. This study adds to a growing literature base that supports that menthol cigarettes, compared to nonmenthol cigarettes, put youth at increased risk for regular cigarette use

Label-free electrochemical monitoring of DNA ligase activity

This study presents a simple, label-free electrochemical technique for the monitoring of DNA ligase activity. DNA ligases are enzymes that catalyze joining of breaks in the backbone of DNA and are of significant scientific interest due to their essential nature in DNA metabolism and their importance to a range of molecular biological methodologies. The electrochemical behavior of DNA at mercury and some amalgam electrodes is strongly influenced by its backbone structure, allowing a perfect discrimination between DNA molecules containing or lacking free ends. This variation in electrochemical behavior has been utilized previously for a sensitive detection of DNA damage involving the sugar-phosphate backbone breakage. Here we show that the same principle can be utilized for monitoring of a reverse process, i.e., the repair of strand breaks by action of the DNA ligases. We demonstrate applications of the electrochemical technique for a distinction between ligatable and unligatable breaks in plasmid DNA using T4 DNA ligase, as well as for studies of the DNA backbone-joining activity in recombinant fragments of E. coli DNA ligase

Brain temperature regulation in poor-grade subarachnoid hemorrhage patients – A multimodal neuromonitoring study

Elevated body temperature (Tcore) is associated with poor outcome after subarachnoid hemorrhage (SAH). Brain temperature (Tbrain) is usually higher than Tcore. However, the implication of this difference (Tdelta) remains unclear. We aimed to study factors associated with higher Tdelta and its association with outcome. We included 46 SAH patients undergoing multimodal neuromonitoring, for a total of 7879 h of averaged data of Tcore, Tbrain, cerebral blood flow, cerebral perfusion pressure, intracranial pressure and cerebral metabolism (CMD). Three-months good functional outcome was defined as modified Rankin Scale ≤2. Tbrain was tightly correlated with Tcore (r = 0.948, p < 0.01), and was higher in 73.7% of neuromonitoring time (Tdelta +0.18°C, IQR −0.01 – 0.37°C). A higher Tdelta was associated with better metabolic state, indicated by lower CMD-glutamate ( p = 0.003) and CMD-lactate ( p < 0.001), and lower risk of mitochondrial dysfunction (MD) (OR = 0.2, p < 0.001). During MD, Tdelta was significantly lower (0°C, IQR −0.2 – 0.1; p < 0.001). A higher Tdelta was associated with improved outcome (OR = 7.7, p = 0.002). Our study suggests that Tbrain is associated with brain metabolic activity and exceeds Tcore when mitochondrial function is preserved. Further studies are needed to understand how Tdelta may serve as a surrogate marker for brain function and predict clinical course and outcome after SAH