Ultrafast Electron Holes in Plasma Phase Space Dynamics

Electron holes (EH) are localized modes in plasma kinetic theory which appear as vortices in phase space. Earlier research on EH is based on the Schamel distribution function (df). A novel distribution function is proposed here, generalizing the original Schamel df in a recursive manner. Nonlinear solutions obtained by kinetic simulations are presented, with velocities twice the electron thermal speed. Using 1D-1V kinetic simulations, their propagation characteristics are traced and their stability is established by studying their long-time evolution and their behavior through mutual collisions.Comment: 5 pages, 6 figures, accepted in Scientific Report

Translucency and the perception of shape

Previous studies have shown that the perceived threedimensional (3D) shape of objects depends on their material composition. The majority of this work has focused on glossy, flat-matte, or velvety materials. Here, we studied perceived 3D shape of translucent materials. We manipulated the spatial frequency of surface relief perturbations of translucent and opaque objects. Observers indicated which of two surfaces appeared to have more bumps. They also judged local surface orientation using gauge probe figures. We found that translucent surfaces appeared to have fewer bumps than opaque surfaces with the same 3D shape (Experiment 1), particularly when self-occluding contours were hidden from view (Experiment 2). We also found that perceived local curvature was underestimated for translucent objects relative to opaque objects, and that estimates of perceived local surface orientation were similarly correlated with luminance for images of both opaque and translucent objects (Experiment 3). These findings suggest that the perceived mesoscopic shape of completely matte translucent objects can be underestimated due to a decline in the steepness of luminance gradients relative to those of opaque objects

DRUG UTILIZATION STUDY OF FLUOROQUINOLONE ANTIBIOTICS IN A UNIVERSITY TEACHING HOSPITAL

It is well known that antibiotics are prescribed abundantly in hospitalized patients especially in critical care settings. The antibiotic usage will also vary depends on the type of therapy, physicians perceptions and availability of the drug. Our aim was to study the drug utilization pattern of Fluoroquinolone (FQs) antibiotics in medicine and surgery wards of a tertiary care hospital. A total of 100 patients who received FQs were enrolled in the study and the FQ utilization was measured in terms of DDD/100 bed days. Mean ± SD number of drugs prescribed and length of hospital stay were 8.23 ± 3.33 and 11.54 ± 7.57 respectively. Ciprofloxacin was the most commonly prescribed drug. Overall Fluoroquinolone utilization was found to be 33.55 DDD/100 bed-days. Key words: Defined daily dose, drug utilization, fluoroquinolones

A RETROSPECTIVE CLINICAL BASED STUDY OF MALARIA IN A UNIVERSITY TEACHING HOSPITAL

N/

Catalyst stabilization by stoichiometrically limited layer-by-layer overcoating in liquid media

The use of metal oxide overcoats over supported nanoparticle catalysts has recently led to impressive improvements in catalyst stability and selectivity. The deposition of alumina is especially important for renewable catalysis due to its robustness in liquid-phase conditions. However, there are limited reports of work on alumina deposition and stabilization that goes beyond atomic layer deposition (ALD). Here, we present a layer-by-layer deposition technique for the controlled formation of conformal alumina overcoats in the liquid phase. This technique is easy to perform in common wet chemistry conditions. Alternated exposure of the substrate to stoichiometric amounts of aluminum alkoxide and water in liquid-phase conditions leads to the formation of a porous overcoat that was easily tunable by varying synthesis parameters. The deposition of 60 Al2O3 layers onto Al2O3-supported copper nanoparticles suppressed irreversible deactivation during the liquid-phase hydrogenation of furfural – a key biomass-derived platform molecule. The porous overcoat leads to highly accessible metal sites, which significantly reduces the partial site blocking observed in equivalent overcoats formed by ALD. We suggest that the ease of scalability and the high degree of control over the overcoat’s properties during liquid-phase synthesis could facilitate the development of new catalyst overcoating applications

Outcome of ACHD patients with non-inducible versus inducible IART undergoing cavo-tricuspid isthmus ablation: the role of empiric ablation

Purpose: Catheter ablation for supraventricular tachycardia (SVT) in adults with congenital heart disease (ACHD) is an important therapeutic option. Cavo-tricuspid isthmus (CTI)-dependent intraatrial re-entrant tachycardia (IART) is common. However, induction of sustained tachycardia at the time of ablation is not always possible. We hypothesised that performing an empiric CTI line in case of non-inducibility leads to good outcomes. Long-term outcomes of empiric versus entrained CTI ablation in ACHD patients were examined. / Methods: Retrospective, single-centre, case-control study over 7 years. Arrhythmia-free survival after empiric versus entrained CTI ablation was compared. / Results: Eighty-seven CTI ablations were performed in 85 ACHD patients between 2010 and 2017. The mean age of the cohort was 43 years and 48% were male. Underlying aetiology included ASD (31%), VSD (11.4%), AVSD (9.1%), AVR (4.8%), Fallot’s (18.4%), Ebstein’s (2.3%), Fontan’s palliation (9.2%) and atrial switch (13.8%). CTI-dependent IART was entrained in 59 patients whereas it was non-inducible in 28. The latter had an empiric CTI ablation. Forty-three percent of procedures were performed under general anaesthesia. There were no reported procedural complications. There was no significant difference in the mean procedure or fluoroscopy times between the groups (empiric vs entrained CTI; 169.1 vs 183.3 and 28.1 vs 19.9 min). Arrhythmia-free survival was 64.3% versus 72.8% (p value 0.44) in the empiric and entrained groups at 21 months follow-up. / Conclusions: Long-term outcomes after empiric and entrained CTI ablation for IART in ACHD patients are comparable. This is a safe and effective therapeutic option. In the case of non-inducibility of IART, an empiric CTI line should be considered in this cohort

Phenotypic and functional characteristics of highly differentiated CD57 +NKG2C + NK cells in HIV-1- infected individuals

Natural killer (NK) cells are important anti-viral effector cells. The function and phenotype of the NK cells that constitute an individual’s NK cell repertoire can be influenced by ongoing and/or previous viral infections. Indeed, infection with human cytomegalovirus (HCMV) drives the expansion of a highly differentiated NK cell population characterized by expression of CD57 and the activating NKG2C receptor. This NK cell population has also been noted to occur in HIV-1-infected individuals. We evaluated the NK cells of HIV-1-infected and –uninfected individuals to determine the relative frequency of highly differentiated CD57 +NKG2C + NK cells and characterize these cells for their receptor expression and responsiveness to diverse stimuli. Highly differentiated CD57 +NKG2C + NK cells occurred at higher frequencies in HCMV-infected donors relative to HCMV-uninfected donors and were dramatically expanded in HIV-1/HCMV co-infected donors. The expanded CD57 +NKG2C + NK cell population in HIV-1-infected donors remained stable following antiretroviral therapy. CD57 +NKG2C + NK cells derived from HIV-1-infected individuals were robustly activated by antibody-dependent stimuli that contained anti-HIV-1 antibodies or therapeutic anti-CD20 antibody, and these NK cells mediated cytolysis through NKG2C. Lastly, CD57 +NKG2C + NK cells from HIV-1-infected donors were characterized by reduced expression of the inhibitory NKG2A receptor. The abundance of highly functional CD57 +NKG2C + NK cells in HIV-1-infected individuals raises the possibility that these NK cells could play a role in HIV-1 pathogenesis or serve as effector cells for therapeutic/cure strategies

Between the Natural and the Artificial: The Sublime Sexual Sensation of Car Crashes in J.G. Ballard’s Crash

At a time when technology progressively pushes back nature, the sexual act runs the risk of being denaturalised. The notion of the sublime, which I argue is how humans react to the machine as a surrogate for nature and as a sexual stimulus in Crash (1973), is therefore of central interest in this article. Ballard himself has described Crash as ‘the first pornographic novel based on technology’ (1973, 6). This engagement with a technologised sexuality is explored as a subjective narrative stance, which grants authenticity to the fictive alter ego, who can probe alternatives to an extra-textual reality. This narrative mode is notably potent in relation to the narrator’s estimation of the merge between sexuality and technology in the form of car crashes uniting Eros and Thanatos. I therefore suggest that Crash can be read as an attempt to localise the natural and human in a world dictated by artificiality and technology

A point-of-care lateral flow assay for neutralising antibodies against SARS-CoV-2

Background: As vaccines against SARS-CoV-2 are now being rolled out, a better understanding of immunity to the virus, whether from infection, or passive or active immunisation, and the durability of this protection is required. This will benefit from the ability to measure antibody-based protection to SARS-CoV-2, ideally with rapid turnaround and without the need for laboratory-based testing. Methods: We have developed a lateral flow POC test that can measure levels of RBD-ACE2 neutralising antibody (NAb) from whole blood, with a result that can be determined by eye or quantitatively on a small instrument. We compared our lateral flow test with the gold-standard microneutralisation assay, using samples from convalescent and vaccinated donors, as well as immunised macaques. Findings: We show a high correlation between our lateral flow test with conventional neutralisation and that this test is applicable with animal samples. We also show that this assay is readily adaptable to test for protection to newly emerging SARS-CoV-2 variants, including the beta variant which revealed a marked reduction in NAb activity. Lastly, using a cohort of vaccinated humans, we demonstrate that our whole-blood test correlates closely with microneutralisation assay data (specificity 100% and sensitivity 96% at a microneutralisation cutoff of 1:40) and that fingerprick whole blood samples are sufficient for this test. Interpretation: Taken together, the COVID-19 NAb-testTM device described here provides a rapid readout of NAb based protection to SARS-CoV-2 at the point of care