Nanoparticles in explosives detection – the state-of-the-art and future directions

No abstract available

Mortality caused by sepsis in patients with end-stage renal disease compared with the general population

Mortality caused by sepsis in patients with end-stage renal disease compared with the general population.BackgroundIn the United States, infection is second to cardiovascular disease as the leading cause of death in patients with end-stage renal disease (ESRD), and septicemia accounts for more than 75% of this category. This increased susceptibility to infections is partly due to uremia, old age, and comorbid conditions. Although it is intuitive to believe that mortality caused by sepsis may be higher in patients with ESRD compared with the general population (GP), no such data are currently available.MethodsWe compared annual mortality rates caused by sepsis in patients with ESRD (U.S. Health Care Financing Administration 2746 death notification form) with those in the GP (death certificate). Data were abstracted from the U.S. Renal Data System (1994 through 1996 Special Data request) and the National Center for Health Statistics. Data were stratified by age, gender, race, and diabetes mellitus (DM). Sensitivity analyses were performed to account for potential limitations of the data sources.ResultsOverall, the annual percentage mortality secondary to sepsis was approximately 100- to 300-fold higher in dialysis patients and 20-fold higher in renal transplant recipients (RTRs) compared with the GP. Mortality caused by sepsis was higher among diabetic patients across all populations. After stratification for age, differences between groups decreased but retained their magnitude. These findings remained robust despite a wide range of sensitivity analyses. Indeed, mortality secondary to sepsis remained approximately 50-fold higher in dialysis patients compared with the GP, using multiple cause-of-death analyses; was approximately 50-fold higher in diabetic patients with ESRD compared with diabetic patients in the GP, when accounting for underreporting of DM on death certificates in the GP; and was approximately 30-fold higher in RTRs compared with the GP, when accounting for the incomplete ascertainment of cause of death among RTRs. Furthermore, despite assignment of primary cause-of-death to major organ infections in the GP, annual mortality secondary to sepsis remained 30- to 45-fold higher in the dialysis population.ConclusionsPatients with ESRD treated by dialysis have higher annual mortality rates caused by sepsis compared with the GP, even after stratification for age, race, and DM. Consequently, this patient population should be considered at high-risk for the development of lethal sepsis

Trace semantics for polymorphic references

Research supported by the Engineering and Physical Sciences Research Council (EP/L022478/1) and the Royal Academy of Engineering

Pathways of the Modified Atlantic Water across the Strait of Sicily

The purpose of this study is to study the medium-scale dynamics, as well as the dynamics of the sub-basin scale in the Central Mediterranean, and to elucidate the routes of the Atlantic waters in this region using a high-resolution numerical model of the eddy-resolving simplest equation. The seasonal variability of the two streams of modified Atlantic waters crossing the Sicilian Strait varies considerably. The main stream along the coast of Tunisia, giving rise to the Atlantic Tunisian current, is stronger than the Atlantic Ionian stream (AIP) from autumn to spring. The Atlantic Tunisian current, which, apparently, is present throughout the year, is characterized by high spatial and temporal variability from the simulation results. The high-resolution model is capable of well reproducing the flow and variability of AIP, including such associating characteristic structures as the Advent Benk Vortex, Moltis Channel Cross, Ionian Benc Vortex and the outflow to the northern Ionian Sea

Sensitive and specific detection of explosives in solution and vapour by surface-enhanced Raman spectroscopy on silver nanocubes

Surface-enhanced Raman spectroscopy (SERS) has been widely utilised as a sensitive analytical technique for the detection of trace levels of organic molecules. The detection of organic compounds in the gas phase is particularly challenging due to the low concentration of adsorbed molecules on the surface of the SERS substrate. This is particularly the case for explosive materials, which typically have very low vapour pressures, limiting the use of SERS for their identification. In this work, silver nanocubes (AgNCs) were developed as a highly sensitive SERS substrate with very low limit-of-detection (LOD) for explosive materials down to the femtomolar (10−15 M) range. Unlike typical gold-based nanostructures, the AgNCs were found suitable for the detection of both aromatic and aliphatic explosives, enabling detection with high specificity at low concentration. SERS studies were first carried out using a model analyte, Rhodamine-6G (Rh-6G), as a probe molecule. The SERS enhancement factor was estimated as 8.71 × 1010 in this case. Further studies involved femtomolar concentrations of 2,4-dinitrotoluene (DNT) and nanomolar concentrations of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), as well as vapour phase detection of DNT

Robustness of Several Estimators of the ACF of AR(1) Process With Non-Gaussian Errors

The autocorrelation function (ACF) plays an important role in the context of ARMA modeling, especially for their identification and estimation. This study considers the robust estimation of the ACF of the AR(1) model if the white noise (WN) process is non- Gaussian. Three estimators including the ordinary moment estimator and two other (robust) estimators are considered. The impacts of the deviation from normality of the WN process on those estimators in terms of bias, MSE and distribution via Monte-Carlo simulation are examined. The empirical distribution of those estimators when the errors are normal, t, Cauchy and exponential are studied. Results show that the moment estimator is more affected by the change of the white noise distribution than other considered estimators