Secrecy performance of TAS/SC-based multi-hop harvest-to-transmit cognitive WSNs under joint constraint of interference and hardware imperfection

In this paper, we evaluate the secrecy performance of multi-hop cognitive wireless sensor networks (WSNs). In the secondary network, a source transmits its data to a destination via the multi-hop relaying model using the transmit antenna selection (TAS)/selection combining (SC) technique at each hop, in the presence of an eavesdropper who wants to receive the data illegally. The secondary transmitters, including the source and intermediate relays, have to harvest energy from radio-frequency signals of a power beacon for transmitting the source data. Moreover, their transmit power must be adjusted to satisfy the quality of service (QoS) of the primary network. Under the joint impact of hardware imperfection and interference constraint, expressions for the transmit power for the secondary transmitters are derived. We also derive exact and asymptotic expressions of secrecy outage probability (SOP) and probability of non-zero secrecy capacity (PNSC) for the proposed protocol over Rayleigh fading channel. The derivations are then verified by Monte Carlo simulations.Web of Science195art. no. 116

A tight coupling between β\u3csub\u3e2\u3c/sub\u3eY97 and β\u3csub\u3e2\u3c/sub\u3eF200 of the GABA\u3csub\u3eA\u3c/sub\u3e receptor mediates GABA binding

The GABAA receptor is an oligopentameric chloride channel that is activated via conformation changes induced upon the binding of the endogenous ligand, GABA, to the extracellular inter-subunit interfaces. Although dozens of amino acid residues at the α/β interface have been implicated in ligand binding, the structural elements that mediate ligand binding and receptor activation are not yet fully described. In this study, double-mutant cycle analysis was employed to test for possible interactions between several arginines (α1R67, α1R120, α1R132, and β2R207) and two aromatic residues (β2Y97 and β2F200) that are present in the ligand-binding pocket and are known to influence GABA affinity. Our results show that neither α1R67 nor α1R120 is functionally coupled to either of the aromatics, whereas a moderate coupling exists between α1R132 and both aromatic residues. Significant functional coupling between β2R207 and both β2Y97 and β2F200 was found. Furthermore, we identified an even stronger coupling between the two aromatics, β2Y97 and β2F200, and for the first time provided direct evidence for the involvement of β2Y97 and β2F200 in GABA binding. As these residues are tightly linked, and mutation of either has similar, severe effects on GABA binding and receptor kinetics, we believe they form a single functional unit that may directly coordinate GABA

Rateless codes-based secure communication employing transmit antenna selection and harvest-to-jam under joint effect of interference and hardware impairments

In this paper, we propose a rateless codes-based communication protocol to provide security for wireless systems. In the proposed protocol, a source uses the transmit antenna selection (TAS) technique to transmit Fountain-encoded packets to a destination in presence of an eavesdropper. Moreover, a cooperative jammer node harvests energy from radio frequency (RF) signals of the source and the interference sources to generate jamming noises on the eavesdropper. The data transmission terminates as soon as the destination can receive a sufficient number of the encoded packets for decoding the original data of the source. To obtain secure communication, the destination must receive sufficient encoded packets before the eavesdropper. The combination of the TAS and harvest-to-jam techniques obtains the security and efficient energy via reducing the number of the data transmission, increasing the quality of the data channel, decreasing the quality of the eavesdropping channel, and supporting the energy for the jammer. The main contribution of this paper is to derive exact closed-form expressions of outage probability (OP), probability of successful and secure communication (SS), intercept probability (IP) and average number of time slots used by the source over Rayleigh fading channel under the joint impact of co-channel interference and hardware impairments. Then, Monte Carlo simulations are presented to verify the theoretical results.Web of Science217art. no. 70

Analysis of Probability of Non-zero Secrecy Capacity for Multi-hop Networks in Presence of Hardware Impairments over Nakagami-m Fading Channels

In this paper, we evaluate probability of non-zero secrecy capacity of multi-hop relay networks over Nakagami-m fading channels in presence of hardware impairments. In the considered protocol, a source attempts to transmit its data to a destination by using multi-hop randomize-and-forward (RF) strategy. The data transmitted by the source and relays are overheard by an eavesdropper. For performance evaluation, we derive exact expressions of probability of non-zero secrecy capacity (PoNSC), which are expressed by sums of infinite series of exponential functions and exponential integral functions. We then perform Monte Carlo simulations to verify the theoretical analysis

Pharmacist-Led Intervention to Enhance Medication Adherence in Patients With Acute Coronary Syndrome in Vietnam:A Randomized Controlled Trial

Background: Patient adherence to cardioprotective medications improves outcomes of acute coronary syndrome (ACS), but few adherence-enhancing interventions have been tested in low-income and middle-income countries. Objectives: We aimed to assess whether a pharmacist-led intervention enhances medication adherence in patients with ACS and reduces mortality and hospital readmission. Methods: We conducted a randomized controlled trial in Vietnam. Patients with ACS were recruited, randomized to the intervention or usual care prior to discharge, and followed 3 months after discharge. Intervention patients received educational and behavioral interventions by a pharmacist. Primary outcome was the proportion of adherent patients 1 month after discharge. Adherence was a combined measure of self-reported adherence (the 8-item Morisky Medication Adherence Scale) and obtaining repeat prescriptions on time. Secondary outcomes were (1) the proportion of patients adherent to medication; (2) rates of mortality and hospital readmission; and (3) change in quality of life from baseline assessed with the European Quality of Life Questionnaire - 5 Dimensions - 3 Levels at 3 months after discharge. Logistic regression was used to analyze data. Registration: ClinicalTrials.gov (NCT02787941). Results: Overall, 166 patients (87 control, 79 intervention) were included (mean age 61.2 years, 73% male). In the analysis excluding patients from the intervention group who did not receive the intervention and excluding all patients who withdrew, were lost to follow-up, died or were readmitted to hospital, a greater proportion of patients were adherent in the intervention compared with the control at 1 month (90.0% vs. 76.5%; adjusted OR = 2.77; 95% CI, 1.01-7.62) and at 3 months after discharge (90.2% vs. 77.0%; adjusted OR = 3.68; 95% CI, 1.14-11.88). There was no significant difference in median change of EQ-5D-3L index values between intervention and control [0.000 (0.000; 0.275) vs. 0.234 (0.000; 0.379); p = 0.081]. Rates of mortality, readmission, or both were 0.8, 10.3, or 11.1%, respectively; with no significant differences between the 2 groups. Conclusion: Pharmacist-led interventions increased patient adherence to medication regimens by over 13% in the first 3 months after ACS hospital discharge, but not quality of life, mortality and readmission. These results are promising but should be tested in other settings prior to broader dissemination

Randomized controlled trial of artesunate or artemether in Vietnamese adults with severe falciparum malaria

<p>Abstract</p> <p>Background</p> <p>Both artemether and artesunate have been shown to be superior to quinine for the treatment of severe falciparum malaria in Southeast Asian adults, although the magnitude of the superiority has been greater for artesunate than artemether. These two artemisinin derivatives had not been compared in a randomized trial.</p> <p>Methods</p> <p>A randomized double blind trial in 370 adults with severe falciparum malaria; 186 received intramuscular artesunate (2.4 mg/kg immediately followed by 1.2 mg/kg at 12 hours then 24 hours then daily) and 184 received intramuscular artemether (3.6 mg per kilogram immediately followed by 1.8 mg per kilogram daily) was conducted in Viet Nam. Both drugs were given for a minimum of 72 hours.</p> <p>Results</p> <p>There were 13 deaths in the artesunate group (7 percent) and 24 in the artemether group (13 percent); P = 0.052; relative risk of death in the patients given artesunate, 0.54; (95 percent confidence interval 0.28-1.02). Parasitaemia declined more rapidly in the artesunate group. Both drugs were very well tolerated.</p> <p>Conclusions</p> <p>Intramuscular artesunate may be superior to intramuscular artemether for the treatment of severe malaria in adults.</p

Intensified Antituberculosis Therapy in Adults with Tuberculous Meningitis

BACKGROUND Tuberculous meningitis is often lethal. Early antituberculosis treatment and adjunctive treatment with glucocorticoids improve survival, but nearly one third of patients with the condition still die. We hypothesized that intensified antituberculosis treatment would enhance the killing of intracerebral Mycobacterium tuberculosis organisms and decrease the rate of death among patients. METHODS We performed a randomized, double-blind, placebo-controlled trial involving human immunodeficiency virus (HIV)-infected adults and HIV-uninfected adults with a clinical diagnosis of tuberculous meningitis who were admitted to one of two Vietnamese hospitals. We compared a standard, 9-month antituberculosis regimen (which included 10 mg of rifampin per kilogram of body weight per day) with an intensified regimen that included higher-dose rifampin (15 mg per kilogram per day) and levofloxacin (20 mg per kilogram per day) for the first 8 weeks of treatment. The primary outcome was death by 9 months after randomization. RESULTS A total of 817 patients (349 of whom were HIV-infected) were enrolled; 409 were randomly assigned to receive the standard regimen, and 408 were assigned to receive intensified treatment. During the 9 months of follow-up, 113 patients in the intensified-treatment group and 114 patients in the standard-treatment group died (hazard ratio, 0.94; 95% confidence interval, 0.73 to 1.22; P=0.66). There was no evidence of a significant differential effect of intensified treatment in the overall population or in any of the subgroups, with the possible exception of patients infected with isoniazid-resistant M. tuberculosis. There were also no significant differences in secondary outcomes between the treatment groups. The overall number of adverse events leading to treatment interruption did not differ significantly between the treatment groups (64 events in the standard-treatment group and 95 events in the intensified-treatment group, P=0.08). CONCLUSIONS Intensified antituberculosis treatment was not associated with a higher rate of survival among patients with tuberculous meningitis than standard treatment. (Funded by the Wellcome Trust and the Li Ka Shing Foundation; Current Controlled Trials number, ISRCTN61649292.)

Combination Antifungal Therapy for Cryptococcal Meningitis

Background Combination antifungal therapy (amphotericin B deoxycholate and flucytosine) is the recommended treatment for cryptococcal meningitis but has not been shown to reduce mortality, as compared with amphotericin B alone. We performed a randomized, controlled trial to determine whether combining flucytosine or high-dose fluconazole with high-dose amphotericin B improved survival at 14 and 70 days. Methods We conducted a randomized, three-group, open-label trial of induction therapy for cryptococcal meningitis in patients with human immunodeficiency virus infection. All patients received amphotericin B at a dose of 1 mg per kilogram of body weight per day; patients in group 1 were treated for 4 weeks, and those in groups 2 and 3 for 2 weeks. Patients in group 2 concurrently received flucytosine at a dose of 100 mg per kilogram per day for 2 weeks, and those in group 3 concurrently received fluconazole at a dose of 400 mg twice daily for 2 weeks. Results A total of 299 patients were enrolled. Fewer deaths occurred by days 14 and 70 among patients receiving amphotericin B and flucytosine than among those receiving amphotericin B alone (15 vs. 25 deaths by day 14; hazard ratio, 0.57; 95% confidence interval [CI], 0.30 to 1.08; unadjusted P=0.08; and 30 vs. 44 deaths by day 70; hazard ratio, 0.61; 95% CI, 0.39 to 0.97; unadjusted P=0.04). Combination therapy with fluconazole had no significant effect on survival, as compared with monotherapy (hazard ratio for death by 14 days, 0.78; 95% CI, 0.44 to 1.41; P=0.42; hazard ratio for death by 70 days, 0.71; 95% CI, 0.45 to 1.11; P=0.13). Amphotericin B plus flucytosine was associated with significantly increased rates of yeast clearance from cerebrospinal fluid (−0.42 log10 colony-forming units [CFU] per milliliter per day vs. −0.31 and −0.32 log10 CFU per milliliter per day in groups 1 and 3, respectively; P<0.001 for both comparisons). Rates of adverse events were similar in all groups, although neutropenia was more frequent in patients receiving a combination therapy. Conclusions Amphotericin B plus flucytosine, as compared with amphotericin B alone, is associated with improved survival among patients with cryptococcal meningitis. A survival benefit of amphotericin B plus fluconazole was not found

Building the hospital event-based surveillance system in Viet Nam: a qualitative study to identify potential facilitators and barriers for event reporting

Introduction: Hospitals are a key source of information for the early identification of emerging disease outbreaks and acute public health events for risk assessment, decision-making, and public health response. The objectives of this study were to identify potential facilitators and barriers for reporting of unusual events from the curative sector to the preventive medicine system in Viet Nam. Methods: In 2016, we conducted 18 semi-structured in-depth interviews and 9 focus group discussions with representatives from the curative and preventive medicine sectors in four provinces. We transcribed the interviews and focus group discussions and conducted a thematic analysis of the factors that appeared to affect public health event reporting. Results: We identified five major themes. Firstly, the lack of a legal framework to guide reporting meant there was an over-reliance on internal procedures. Secondly, participants reported the importance of an enabling environment to facilitate reporting such as leadership support and having focal points for reporting. Thirdly, potential benefits for reporting were seen such as support during outbreaks and receiving feedback. Fourthly, some challenges prohibited timely reporting such as not perceiving reporting to be the task of the curative sector and hesitancy to report without laboratory confirmation. Finally, the limited resources and specialist capacities in remote areas hindered timely detection and reporting of unusual events. Discussion: This study identified potential opportunities to promote the detection and reporting of unusual events from health care workers to the public health sector, and thus improving the overall health security system in Viet Nam and beyond

Photonic fractal metamaterials: a metal–semiconductor platform with enhanced volatile‐compound sensing performance

Advance of photonics media is restrained by the lack of structuring techniques for the 3D fabrication of active materials with long‐range periodicity. A methodology is reported for the engineering of tunable resonant photonic media with thickness exceeding the plasmonic near‐field enhancement region by more than two orders of magnitude. The media architecture consists of a stochastically ordered distribution of plasmonic nanocrystals in a fractal scaffold of high‐index semiconductors. This plasmonic‐semiconductor fractal media supports the propagation of surface plasmons with drastically enhanced intensity over multiple length scales, overcoming the 2D limitations of established metasurface technologies. The fractal media are used for the fabrication of plasmonic optical gas sensors, achieving a limit of detection of 0.01 vol% at room temperature and sensitivity up to 1.9 nm vol%−1, demonstrating almost a fivefold increase with respect to an optimized planar geometry. Beneficially to their implementation, the self‐assembly mechanism of this fractal architecture allows fabrication of micrometer‐thick media over surfaces of several square centimeters in a few seconds. The designable optical features and intrinsic scalability of these photonic fractal metamaterials provide ample opportunities for applications, bridging across transformation optics, sensing, and light harvesting