Coherent Signal Amplification in Bistable Nanomechanical Oscillators by Stochastic Resonance

Stochastic resonance is a counter-intuitive concept[1,2], ; the addition of noise to a noisy system induces coherent amplification of its response. First suggested as a mechanism for the cyclic recurrence of ice ages, stochastic resonance has been seen in a wide variety of macroscopic physical systems: bistable ring lasers[3], SQUIDs[4,5], magnetoelastic ribbons[6], and neurophysiological systems such as the receptors in crickets[7] and crayfish[8]. Although it is fundamentally important as a mechanism of coherent signal amplification, stochastic resonance is yet to be observed in nanoscale systems. Here we report the observation of stochastic resonance in bistable nanomechanical silicon oscillators, which can play an important role in the realization of controllable high-speed nanomechanical memory cells. Our nanomechanical systems were excited into a dynamic bistable state and modulated in order to induce controllable switching; the addition of white noise showed a marked amplification of the signal strength. Stochastic resonance in nanomechanical systems paves the way for exploring macroscopic quantum coherence and tunneling, and controlling nanoscale quantum systems for their eventual use as robust quantum logic devices.Comment: 18 pages, 4 figure

Food allergy, airborne allergies, and allergic sensitisation among adolescents living in two disparate socioeconomic regions in Ecuador: A cross-sectional study

Background Allergic diseases are under-investigated and overlooked health conditions in developing countries. We measured the prevalence of food allergy (FA), airborne allergic disease, and allergic sensitisation among adolescents living in 2 socio-demographically disparate regions in Ecuador. We investigated which risk factors are associated with these conditions. Methods A cross-sectional study involved 1338 students (mean age: 13 ± 0.9 years old) living in Cuenca (n = 876) and Santa Isabel (n = 462). History of allergic symptoms (noted by parents or doctor) to food, house dust mites (HDM), pollen, and pets were recorded. Sociodemographic characteristics, environmental exposures, and parental history of allergic disorders data were collected. Sensitisation to 19 food and 20 aeroallergens was measured by skin-prick testing (SPT). FA and airborne allergic diseases (to HDM, pollen, cat, or dog) were defined as a report of allergic symptoms noted by doctor, together with a positive SPT (wheal size ≥3 mm). Logistic regression models were used to identify environmental and parental factors associated with allergic conditions. Results FA was prevalent among 0.4% (95% CI 0.2%–0.9%), and food sensitisation among 19.1% of the adolescents. Shrimp was the most frequent food linked with FA and food sensitisation. Risk factors associated with FA could not be evaluated due to the low prevalence. Food sensitisation was higher among adolescents exposed to family smoking (OR 1.63, 95% CI 1.14–2.34, p = 0.008) and those with parental history of allergic disorders (OR 1.68, 95% CI 1.13–2.49, p = 0.01), but less common among adolescents owning dogs (OR 0.59, 95% CI 0.41–0.84, p = 0.003). Airborne allergic diseases were prevalent amongst 12.0% of the adolescents (95% CI: 10.4–13.9, n = 1321), with HDM as the primary allergen (11.2%). Airborne allergic diseases were less common among adolescents with more siblings (OR 0.79, 95% CI 0.65–0.96, p = 0.02) and those who lived with farm animals in the first year of life (OR 0.47, 95% CI 0.23–0.95, p = 0.04), but, most common among adolescents with a smoking family (OR 1.67, 95% CI 1.04–2.70, p = 0.03) and with a parental history of allergic disorders (OR self-perceived: 2.62, 95% CI 1.46–4.71, p = 0.001; OR diagnosed by a doctor: 4.07, 95% CI 2.44–6.80, p < 0.001). Conclusions FA and airborne allergies are less prevalent in Ecuador than in developed regions; there is a great dissociation between the prevalence of allergic disease and allergic sensitisation. Shrimp and HDM were the most prevalent allergens. Risk factors identified in this study to be related to allergic diseases should be considered by physicians, health practitioners, and epidemiologists in Ecuador

Drug Resistance in Eukaryotic Microorganisms

Eukaryotic microbial pathogens are major contributors to illness and death globally. Although much of their impact can be controlled by drug therapy as with prokaryotic microorganisms, the emergence of drug resistance has threatened these treatment efforts. Here, we discuss the challenges posed by eukaryotic microbial pathogens and how these are similar to, or differ from, the challenges of prokaryotic antibiotic resistance. The therapies used for several major eukaryotic microorganisms are then detailed, and the mechanisms that they have evolved to overcome these therapies are described. The rapid emergence of resistance and the restricted pipeline of new drug therapies pose considerable risks to global health and are particularly acute in the developing world. Nonetheless, we detail how the integration of new technology, biological understanding, epidemiology and evolutionary analysis can help sustain existing therapies, anticipate the emergence of resistance or optimize the deployment of new therapies

Life-threatening infections in children in Europe (the EUCLIDS Project): a prospective cohort study

Background: Sepsis and severe focal infections represent a substantial disease burden in children admitted to hospital. We aimed to understand the burden of disease and outcomes in children with life-threatening bacterial infections in Europe. Methods: The European Union Childhood Life-threatening Infectious Disease Study (EUCLIDS) was a prospective, multicentre, cohort study done in six countries in Europe. Patients aged 1 month to 18 years with sepsis (or suspected sepsis) or severe focal infections, admitted to 98 participating hospitals in the UK, Austria, Germany, Lithuania, Spain, and the Netherlands were prospectively recruited between July 1, 2012, and Dec 31, 2015. To assess disease burden and outcomes, we collected demographic and clinical data using a secured web-based platform and obtained microbiological data using locally available clinical diagnostic procedures. Findings: 2844 patients were recruited and included in the analysis. 1512 (53·2%) of 2841 patients were male and median age was 39·1 months (IQR 12·4–93·9). 1229 (43·2%) patients had sepsis and 1615 (56·8%) had severe focal infections. Patients diagnosed with sepsis had a median age of 27·6 months (IQR 9·0–80·2), whereas those diagnosed with severe focal infections had a median age of 46·5 months (15·8–100·4; p<0·0001). Of 2844 patients in the entire cohort, the main clinical syndromes were pneumonia (511 [18·0%] patients), CNS infection (469 [16·5%]), and skin and soft tissue infection (247 [8·7%]). The causal microorganism was identified in 1359 (47·8%) children, with the most prevalent ones being Neisseria meningitidis (in 259 [9·1%] patients), followed by Staphylococcus aureus (in 222 [7·8%]), Streptococcus pneumoniae (in 219 [7·7%]), and group A streptococcus (in 162 [5·7%]). 1070 (37·6%) patients required admission to a paediatric intensive care unit. Of 2469 patients with outcome data, 57 (2·2%) deaths occurred: seven were in patients with severe focal infections and 50 in those with sepsis. Interpretation: Mortality in children admitted to hospital for sepsis or severe focal infections is low in Europe. The disease burden is mainly in children younger than 5 years and is largely due to vaccine-preventable meningococcal and pneumococcal infections. Despite the availability and application of clinical procedures for microbiological diagnosis, the causative organism remained unidentified in approximately 50% of patients

Food allergy, airborne allergies, and allergic sensitisation among adolescents living in two disparate socioeconomic regions in Ecuador: A cross-sectional study

Background Allergic diseases are under-investigated and overlooked health conditions in developing countries. We measured the prevalence of food allergy (FA), airborne allergic disease, and allergic sensitisation among adolescents living in 2 socio-demographically disparate regions in Ecuador. We investigated which risk factors are associated with these conditions. Methods A cross-sectional study involved 1338 students (mean age: 13 ± 0.9 years old) living in Cuenca (n = 876) and Santa Isabel (n = 462). History of allergic symptoms (noted by parents or doctor) to food, house dust mites (HDM), pollen, and pets were recorded. Sociodemographic characteristics, environmental exposures, and parental history of allergic disorders data were collected. Sensitisation to 19 food and 20 aeroallergens was measured by skin-prick testing (SPT). FA and airborne allergic diseases (to HDM, pollen, cat, or dog) were defined as a report of allergic symptoms noted by doctor, together with a positive SPT (wheal size ≥3 mm). Logistic regression models were used to identify environmental and parental factors associated with allergic conditions. Results FA was prevalent among 0.4% (95% CI 0.2%–0.9%), and food sensitisation among 19.1% of the adolescents. Shrimp was the most frequent food linked with FA and food sensitisation. Risk factors associated with FA could not be evaluated due to the low prevalence. Food sensitisation was higher among adolescents exposed to family smoking (OR 1.63, 95% CI 1.14–2.34, p = 0.008) and those with parental history of allergic disorders (OR 1.68, 95% CI 1.13–2.49, p = 0.01), but less common among adolescents owning dogs (OR 0.59, 95% CI 0.41–0.84, p = 0.003). Airborne allergic diseases were prevalent amongst 12.0% of the adolescents (95% CI: 10.4–13.9, n = 1321), with HDM as the primary allergen (11.2%). Airborne allergic diseases were less common among adolescents with more siblings (OR 0.79, 95% CI 0.65–0.96, p = 0.02) and those who lived with farm animals in the first year of life (OR 0.47, 95% CI 0.23–0.95, p = 0.04), but, most common among adolescents with a smoking family (OR 1.67, 95% CI 1.04–2.70, p = 0.03) and with a parental history of allergic disorders (OR self-perceived: 2.62, 95% CI 1.46–4.71, p = 0.001; OR diagnosed by a doctor: 4.07, 95% CI 2.44–6.80, p < 0.001). Conclusions FA and airborne allergies are less prevalent in Ecuador than in developed regions; there is a great dissociation between the prevalence of allergic disease and allergic sensitisation. Shrimp and HDM were the most prevalent allergens. Risk factors identified in this study to be related to allergic diseases should be considered by physicians, health practitioners, and epidemiologists in Ecuador