NDM-526: INVESTIGATION OF STABLE AND UNSTABLE FIBER-REINFORCED ELASTOMERIC ISOLATORS

Fiber-reinforced elastomeric isolators (FREIs) are a potentially low-cost alternative to conventional steel-reinforced elastomeric isolators. FREIs can exhibit a non-linear horizontal force-displacement relationship characterized by a softening and stiffening phase, similar to other adaptive isolation devices such as the triple friction pendulum. This non-linear relationship is a consequence of unique deformations that occur during horizontal displacement denoted as rollover, which causes softening, and full rollover, which causes stiffening. The magnitude of the softening due to rollover is primarily governed by the width-to-total height aspect ratio of the FREI. If the aspect ratio is low, below about 2.5, the isolator may be susceptible to horizontal instability where the tangential stiffness becomes negative before increasing due to full rollover. Design codes prevent the use of an isolation system susceptible to horizontal instability within the design displacement. In this paper, experimental testing is used to calibrate a numerical model of a base isolated structure using horizontally unstable and stable FREIs. The performance of the structure is evaluated based on peak displacement of the isolation layer and peak acceleration of the base isolated structure. For the isolators considered, it is shown that the horizontal instability does not have a negative impact on the performance of the structure. It is postulated that some level of horizontal instability may be allowed in the design of unbonded FREIs

Modelling the impact of local reactive school closures on critical care provision during an influenza pandemic

Despite the fact that the 2009 H1N1 pandemic influenza strain was less severe than had been feared, both seasonal epidemics of influenza-like-illness and future influenza pandemics have the potential to place a serious burden on health services. The closure of schools has been postulated as a means of reducing transmission between children and hence reducing the number of cases at the peak of an epidemic; this is supported by the marked reduction in cases during school holidays observed across the world during the 2009 pandemic. However, a national policy of long-duration school closures could have severe economic costs. Reactive short-duration closure of schools in regions where health services are close to capacity offers a potential compromise, but it is unclear over what spatial scale and time frame closures would need to be made to be effective. Here, using detailed geographical information for England, we assess how localized school closures could alleviate the burden on hospital intensive care units (ICUs) that are reaching capacity. We show that, for a range of epidemiologically plausible assumptions, considerable local coordination of school closures is needed to achieve a substantial reduction in the number of hospitals where capacity is exceeded at the peak of the epidemic. The heterogeneity in demand per hospital ICU bed means that even widespread school closures are unlikely to have an impact on whether demand will exceed capacity for many hospitals. These results support the UK decision not to use localized school closures as a control mechanism, but have far wider international public-health implications. The spatial heterogeneities in both population density and hospital capacity that give rise to our results exist in many developed countries, while our model assumptions are sufficiently general to cover a wide range of pathogens. This leads us to believe that when a pandemic has severe implications for ICU capacity, only widespread school closures (with their associated costs and organizational challenges) are sufficient to mitigate the burden on the worst-affected hospitals

Evaluation of the implementation of a state government community design policy aimed at increasing local walking: Design issues and baseline results from RESIDE, Perth Western Australia

Objectives. To describe the design and baseline results of an evaluation of the Western Australian government's pedestrian-friendly subdivision design code (Liveable Neighborhood (LN) Guidelines). Methods. Baseline results (2003–2005) from a longitudinal study of people (n=1813) moving into new housing developments: 18 Liveable, 11 Hybrid and 45 Conventional (i.e., LDs, HDs and CDs respectively) are presented including usual recreational and transport related walking undertaken within and outside the neighborhood, and 7-day pedometer steps. Results. At baseline, more participants walked for recreation and transport within the neighborhood (52.6%; 36.1% respectively), than outside the neighborhood (17.7%; 13.2% respectively). Notably, only 20% of average total duration of walking (128.4 min/week (SD159.8)) was transport related and within the neighborhood. There were few differences between the groups' demographic, psychosocial and perceived neighborhood environmental characteristics, pedometer steps, or the type, amount and location of self-reported walking ( pN0.05). However, asked what factors influenced their choice of housing development, more participants moving into LDs reported aspects of their new neighborhood's walkability as important ( pb0.05). Conclusions. The baseline results underscore the desirability of incorporating behavior and context-specific measures and value of longitudinal designs to enable changes in behavior, attitudes, and urban form to be monitored, while adjusting for baseline residential location preferences

Non-inhibitory levels of oxygen during cultivation increase freeze-drying stress tolerance in Limosilactobacillus reuteri DSM 17938

The physiological effects of oxygen on Limosilactobacillus reuteri DSM 17938 during cultivation and the ensuing properties of the freeze-dried probiotic product was investigated. On-line flow cytometry and k-means clustering gating was used to follow growth and viability in real time during cultivation. The bacterium tolerated aeration at 500mL/min, with a growth rate of 0.74 +/- 0.13h(-1) which demonstrated that low levels of oxygen did not influence the growth kinetics of the bacterium. Modulation of the redox metabolism was, however, seen already at non-inhibitory oxygen levels by 1.5-fold higher production of acetate and 1.5-fold lower ethanol production. A significantly higher survival rate in the freeze-dried product was observed for cells cultivated in presence of oxygen compared to absence of oxygen (61.8%+/- 2.4% vs. 11.5%+/- 4.3%), coinciding with a higher degree of unsaturated fatty acids (UFA:SFA ratio of 10 for air sparged vs. 3.59 for N-2 sparged conditions.). Oxygen also resulted in improved bile tolerance and boosted 5 ' nucleotidase activity (370U/L vs. 240U/L in N-2 sparged conditions) but lower tolerance to acidic conditions compared bacteria grown under complete anaerobic conditions which survived up to 90min of exposure at pH 2. Overall, our results indicate the controlled supply of oxygen during production may be used as means for probiotic activity optimization of L. reuteri DSM 17938

Distinct RNA profiles in subpopulations of extracellular vesicles: apoptotic bodies, microvesicles and exosomes

Introduction: In recent years, there has been an exponential increase in the number of studies aiming to understand the biology of exosomes, as well as other extracellular vesicles. However, classification of membrane vesicles and the appropriate protocols for their isolation are still under intense discussion and investigation. When isolating vesicles, it is crucial to use systems that are able to separate them, to avoid cross-contamination. Method: EVs released from three different kinds of cell lines: HMC-1, TF-1 and BV-2 were isolated using two centrifugation-based protocols. In protocol 1, apoptotic bodies were collected at 2,000×g, followed by filtering the supernatant through 0.8 µm pores and pelleting of microvesicles at 12,200×g. In protocol 2, apoptotic bodies and microvesicles were collected together at 16,500×g, followed by filtering of the supernatant through 0.2 µm pores and pelleting of exosomes at 120,000×g. Extracellular vesicles were analyzed by transmission electron microscopy, flow cytometry and the RNA profiles were investigated using a Bioanalyzer®. Results: RNA profiles showed that ribosomal RNA was primary detectable in apoptotic bodies and smaller RNAs without prominent ribosomal RNA peaks in exosomes. In contrast, microvesicles contained little or no RNA except for microvesicles collected from TF-1 cell cultures. The different vesicle pellets showed highly different distribution of size, shape and electron density with typical apoptotic body, microvesicle and exosome characteristics when analyzed by transmission electron microscopy. Flow cytometry revealed the presence of CD63 and CD81 in all vesicles investigated, as well as CD9 except in the TF-1-derived vesicles, as these cells do not express CD9. Conclusions: Our results demonstrate that centrifugation-based protocols are simple and fast systems to distinguish subpopulations of extracellular vesicles. Different vesicles show different RNA profiles and morphological characteristics, but they are indistinguishable using CD63-coated beads for flow cytometry analysis

Type 2 diabetes in South Asians compared to Europeans: higher risk and earlier development of major cardiovascular events irrespective of the presence and degree of retinopathy. Results from The HinDu The Hague Diabetes Study

Introduction South Asians with diabetes have more severe diabetic retinopathy (DR) and cardiovascular complications than white Caucasians. However, how big this gap is and the relation with the severity of DR has not been studied. Here, we quantify the difference in time from diabetes diagnosis until a first non-fatal Major Adverse Cardiovascular Event (TUF MACE) in different DR groups in South Asians and Europeans. Methods 3831 adults with type 2 diabetes, 1358 South Asians and 2473 Europeans, treated in our diabetes clinic between 2006 and 2017 were included. Data on risk factors, diabetes duration, age of diagnosis and diabetes complications were collected from the diabetes-specific database and analysed using descriptive statistics and Cox regression. DR was graded in 3 categories, and non-fatal MACE was pre-specified. Results Prevalence of non-fatal MACE was the same when DR was absent, increased with increasing severity of DR in both ethnic groups, but was more frequent in South Asians with DR (mild: 50 vs. 42% and severe 62 vs. 46%. Classic risk factors only differed in relation to smoking habits, which were significantly lower in South Asians. After correction for classic risk factors and age at diabetes diagnosis TUF MACE was significantly shorter in South Asians, an effect also seen in the no-DR group (4.1 yrs. HR 1.5, 95% CI 1.3-1.8 and 7.4 yrs. earlier, HR 2.0, 95% CI 1.6-2.6 for no-DR and severe DR, respectively). Conclusions When adjusted for age at diabetes diagnosis, we show that time until first non-fatal MACE in South Asians is significantly shorter compared to Europeans and increases from no- to severe DR.Prevention, Population and Disease management (PrePoD)Public Health and primary car

Non-inhibitory levels of oxygen during cultivation increase freeze-drying stress tolerance in Limosilactobacillus reuteri DSM 17938

The physiological effects of oxygen on Limosilactobacillus reuteri DSM 17938 during cultivation and the ensuing properties of the freeze-dried probiotic product was investigated. On-line flow cytometry and k-means clustering gating was used to follow growth and viability in real time during cultivation. The bacterium tolerated aeration at 500 ml/min, with a growth rate of 0.74 ± 0.13 h-1 which demonstrated that low levels of oxygen did not influence the growth kinetics of the bacterium. Modulation of the redox metabolism was, however, seen already at non-inhibitory oxygen levels by 1.5-fold higher production of acetate and 1.5-fold lower ethanol production. A significantly higher survival rate in the freeze-dried product was observed for cells cultivated in presence of oxygen compared to absence of oxygen (61.8 ± 2.4 % vs 11.5 ± 4.3 %), coinciding with a higher degree of unsaturated fatty acids (UFA:SFA ratio of 10 for air sparged vs 3.59 for N2 sparged conditions.). Oxygen also resulted in improved bile tolerance and boosted 5’nucleotidase activity (370 U/L vs 240 U/L in N2 sparged conditions) but lower tolerance to acidic conditions compared bacteria grown under complete anaerobic conditions which survived up to 90 min of exposure at pH 2. Overall, our results indicate the controlled supply of oxygen during production may be used as means for probiotic activity optimisation of L. reuteri DSM 17938