Chemical aspects related to using recycled geopolymers as aggregates

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Despite extensive research into sustainability of geopolymers, end-of-life aspects have been largely overlooked. A recycling scenario is examined in this study. This requires an investigation of alkali leaching potential from a geopolymeric matrix. To study the feasibility of geopolymer cement (GPC) recycling, the migration of alkalis was evaluated for the first time on a microstructural level through energy dispersive X-ray (EDX) scanning electron microscopy (SEM) elemental mapping and leaching tests. Macroscale impacts were assessed through an investigation of Portland cement (PC) mortar properties affected by alkali concentration. Leaching tests indicated that alkalis immediately become available in aqueous environments, but the majority remain chemically or physically bound in the matrix. This type of leaching accelerates the initial setting of PC paste. Elemental mapping and EDX/SEM analysis showed a complex paste-aggregate interfacial transition zone. Exchange of calcium and sodium, revealed by the maps, resulted in the migration of sodium into the PC paste and the formation of additional calcium-silicon-based phases in the geopolymeric matrix. Strength values of mortars with 25% and 50% recycled aggregates (RA) showed negligible differences compared with the reference sample. Screening tests indicated a low potential for GPC RA inducing alkali-silica reaction. Transport of GPC RA alkalis and the underlying mechanisms were observed. This transport phenomenon was found to have minor effects on the properties of the PC mortar, indicating that recycling of geopolymers is a viable reuse practice.Peer reviewedFinal Published versio

Limiting Behaviour of the Mean Residual Life

In survival or reliability studies, the mean residual life or life expectancy is an important characteristic of the model. Here, we study the limiting behaviour of the mean residual life, and derive an asymptotic expansion which can be used to obtain a good approximation for large values of the time variable. The asymptotic expansion is valid for a quite general class of failure rate distributions--perhaps the largest class that can be expected given that the terms depend only on the failure rate and its derivatives.Comment: 19 page

CMS endcap RPC gas gap production for upgrade

The CMS experiment will install a RE4 layer of 144 new Resistive Plate Chambers (RPCs) on the existing york YE3 at both endcap regions to trigger high momentum muons from the proton-proton interaction. In this paper, we present the detailed procedures used in the production of new RPC gas gaps adopted in the CMS upgrade. Quality assurance is enforced as ways to maintain the same quality of RPC gas gaps as the existing 432 endcap RPC chambers that have been operational since the beginning of the LHC operation

V’O2 kinetics in response to High-Intensity-Interval Training (HIT) and isoinertial resistance training (IRT) in older, healthy men

High intensity exercise training (HIT) accelerates V’O2 kinetics (VO2k) in older subjects. It is controversial whether IRT may elicit the same adaptation. We explored the effect of HIT and IRT on VO2k and muscle deoxygenation during moderate intensity exercise in older, healthy men. 12 men (68 yy ± 4) were exposed to 8 weeks (3 times a week) of: i) HIT, and, after 4 months, ii) IRT performed with an isoinertial YoYo. Before and after training we measured: i) V’O2 peak (V’O2p); ii) breath-by-breath V’O2 and fractional muscle O2 extraction (∆HHb) of vastus lateralis by quantitative NIRS during step-exercise transitions of moderate intensity. VO2k was modeled by means of a double - exponential function to obtain the time constant (Tau) of its primary component. The normalized ∆HHb to ∆V’O2 ratio (∆HHb/∆V’O2) was calculated as and index of the matching between muscular O2 delivery (VO2m) and uptake (QaO2). V’O2p increased after HIT (29.9 mL min-1 kg-1 ± 4.3 - 32.6 mL min-1 kg-1± 6.0, p<0.05); it was not affected by IRT. Tau decreased after HIT (26.97 s ± 5.54 - 19.63 s ± 4.31, p<0.05); it did not change after IRT. Peak ∆HHb/∆V’O2 was smaller after HIT (1.83 ± 0.63 - 1.23 ± 0.37, p<0.05); it was not affected by IRT. 8 weeks of HIT accelerated V’O2k and improved the matching between QaO2 and VO2m. IRT did not lead to any improvement of ∆HHb/∆V’O2 and left V’O2k unchanged. Results suggest that the acceleration of V’O2k was mainly due to the improved matching of VO2m to QaO2

EFFECT OF HIGH INTENSITY TRAINING AND ISOINERTIAL TRAINING ON MUSCLE FUNCTIONS IN OLDER ADULTS

Introduction Maximal muscle strength is a strong predictor of functional skills and ability to maintain independent living in elderly. Muscle contraction properties has been shown to decline to a greater extent than muscle strength with aging and it has been considered the main responsible of the observed decline in functional status (Izquierdo et al., 1999). Endurance high intensity interval training (HIT), by involving large muscle groups, and eccentric strength exercise (IRT), by producing high mechanical loads, could be used in elderly to improve muscle function and quality of life (Milanovi et al., 2015). Therefore, the aim of this study was to examine the changes in muscle properties in elderly after 8 wk of HIT and IRT. Methods 12 moderately active older adults (age: 69.4±4.3 yy; BMI: 22.9±2.7 kg/m2; V’O2max: 29.5±4.1 mL/kg/min) have completed 8 wk of: i) HIT, 7 two-minute cycling repetitions at 90% of V’O2max, 3 times/wk, and, after 4 months, ii) IRT performed with an isoinertial leg press (YoYo TechnologyAB) comprised 4×7 maximal concentric-eccentric knee extensions, 3 times/wk. Maximum voluntary contraction (MVC) was measured using a cell load in a custom-made setup (90° knee flexion). Electrically evoked muscle single twitch was superimposed onto MVC: neuromuscular activation (NA) was calculated as the ratio between the amplitudes of the superimposed and resting twitches. Muscle volume of the quadriceps (Qvol) was obtained by MRI scans. Results MVC at 90° knee flexion, increase significantly only after IRT (P < 0.01). Both training modalities affected significantly NA (P < 0.05): +12.4% after HIT and +14.2 after IRT. Similarly, Qvol increase by 5.1% (P < 0.05) after HIT intervention and by 4.9% (P < 0.05) after IRT. Discussion Our results confirm the feasibility and effectiveness of HIT and IRT to improve muscle qualities: 8 wk of specific training are able to modify muscle mass, MVC and neuromuscular activation in elderly subjects. This stresses the importance of using effective approaches such as exercise treatment with high loads and high intensities in the prevention of disuse in elderly individuals who are concurrently exposed to the deleterious effects of aging on muscle contractile function and mass (Behrens et al., 2016). We can therefore speculate that the two proposed training modalities may be helpful in improving functional status and prevent frailty in elderly subjects. References Izquierdo M, Aguado X, Gonzalez R, Lopez JL, Hakkinen K. (1999). Eur J Appl Physiol Occup Physiol, 79, 260-7. Milanovi Z, Sporiš G, Weston M. (2015). Sports Med, 45(10), 1469-81. Behrens M, Brown N, Bollinger R, Bubeck D, Mau-Moeller A, Weippert M, Zschorlich V, Bruhn S, Alt W. (2016). Appl Physiol Nutr Metab, 41(1), 110-3

SPEEDING OF V’O2 KINETICS IN RESPONSE TO HIGH-INTENSITY-INTERVAL TRAINING IN OLDER, HEALTHY MEN

Introduction Experimental evidence suggests that High Intensity Interval Training (HIT, high intensity - low volume exercise) may be effective in accelerating the dynamic response pulmonary O2 uptake (V’O2) in older subjects through an improvement of the matching between local O2 delivery and uptake (Williams et al., 2013). This study explores the effect of HIT on V’O2 kinetics and muscle deoxygenating during step transitions of moderate intensity, cycling exercise in older, healthy men. Methods 12 moderately active older adults (68-yy ± 4) were exposed to 8 weeks of HIT training with 7 two-minute repetitions at 40 and 90% of V ̇O2max, 3 times a week. Before and after training we measured: i) V’O2 peak (V’O2p), gas exchange threshold (GET) and respiratory compensation point (RCP) during an incremental test up to exhaustion; ii) breath-by-breath V’O2 and change of fractional muscle O2 extraction (ΔHHb) of vastus lateralis by quantitative NIRS during three step-exercise transitions performed at a workload corresponding to 90% of GET. V’O2 kinetics was modeled, after synchronization and overlapping of the three series, by means of a double - exponential function so that we estimated the time constant (Tau) of the primary component of VO2 kinetics. Finally, the normalized ΔHHb to ΔV’O2 ratio was obtained as index of the matching between muscular O2 delivery and uptake (De Roia et al., 2012; Murias et al., 2011). Results V’O2max increased by 9% (29.9 mL min-1 kg-1 ±4.3 - 32.6 mL min-1 kg-1± 6.0, p<0.01, ES 0.51) after 8 weeks of HIT. RCP (respiratory compensation point, per cent of V’O2max) significantly improved by 10% (76.4 % ± 8.3 - 82.9 % ± 4.9, p<0.05, ES 0.97); Tau decreased by about 26% (26.97 s ± 5.54 - 19.63 s ± 4.31, p<0.001, ES 1.48), suggesting a substantial acceleration of V’O2 kinetics; peak value of ΔHHb to ΔV’O2 ratio was smaller after HIT (∼ 29%) (1.83 ± 0.63 - 1.23 ± 0.37, p<0.01, ES 1.17). Discussion This study shows that 8 weeks of HIT were sufficient to induce a significant acceleration of V’O2 kinetics during moderate intensity exercise and to improve the matching between muscular O2 delivery and uptake in older, healthy men. These results suggest that the acceleration of the dynamic response of aerobic metabolism was due to an improved matching of O2 utilization to microvascular delivery. References Williams AM, Paterson DH, Kowalchuk JM. (2013) J Appl Physiol 114, 1550–1562. De Roia G, Pogliaghi S, Adami A, Papadopoulou C, Capelli C. (2012) Am J Physiol Regul Integr Comp Physiol. 302, R1158- R1166. Murias JM, Spencer MD, DeLorey DS, Gurd BJ, Kowalchuk JM, Paterson DH. (2011) J Appl Physiol 111, 1410–1415

A smartphone-based chemosensor to evaluate antioxidants in agri-food matrices by in situ AuNP formation

In recent years, there has been a continuously growing interest in antioxidants by both customers and food industry. The beneficial health effects of antioxidants led to their widespread use in fortified functional foods, as dietary supplements and as preservatives. A variety of analytical methods are available to evaluate the total antioxidant capacity (TAC) of food extracts and beverages. However, most of them are expensive, time-consuming, and require laboratory instrumentation. Therefore, simple, cheap, and fast portable sensors for point-of-need measurement of antioxidants in food samples are needed. Here, we describe a smartphone-based chemosensor for on-site assessment of TAC of aqueous matrices, relying on the antioxidant-induced formation of gold nanoparticles. The reaction takes place in ready-to-use analytical cartridges containing an hydrogel reaction medium preloaded with Au(III) and is monitored by using the smartphone’s CMOS camera. An analytical device including an LED-based lighting system was developed to ensure uniform and reproducible illumination of the analytical cartridge. The chemosensor permitted rapid TAC measurements of aqueous samples, including teas, herbal infusions, beverages, and extra virgin olive oil extracts, providing results that correlated with those of the reference methods for TAC assessment, e.g., oxygen radical absorbance capacity (ORAC)

Unraveling the effect of proliferative stress in vivo in hematopoietic stem cell gene therapy mouse study

The hematopoietic system of patients enrolled in hematopoietic stem cells (HSC) gene therapy (GT) treatments is fully reconstituted upon autologous transplantation of engineered stem cells. HSCs highly proliferate up to full restoration of homeostasis and compete for niche homing and engraftment. The impact of the proliferation stress in HSC on genetic instability remains an open question that cured patients advocate for characterizing long-term safety and efficacy. The accumulation of somatic mutations has been widely used as a sensor of proliferative stress. Vector integration site (IS) can be used as a molecular tool for clonal identity, inherited by all HSC progeny, to uncover lineage dynamics in vivo at single-cell level. Here we characterized at single-clone granularity the proliferative stress of HSCs and their progeny over time by measuring the accumulation of mutations from the DNA of each IS. To test the feasibility of the approach, we set-up an experimental framework that combines tumor-prone Cdkn2a-/- and wild type (WT) mouse models of HSC-GT and molecular analyses on different hematopoietic cell lineages after transplantation of HSCs transduced with genotoxic LV (LV.SF.LTR) or GT-like non-genotoxic LV (SIN.LV.PGK). The Cdkn2a-/- mouse model provided the experimental conditions to detect the accumulation of somatic mutations, since the absence of p16INK4A and p19ARF enhances the proliferative potential of cells that have acquired oncogenic mutations. As expected, mice transplanted with Cdkn2a-/- Lin- cells marked with LV.SF.LTR (N=24) developed tumors significantly earlier compared to mock (N=20, p<0.0001), while mice treated with SIN. LV.PGK (N=23) did not. On the other side, mice that received WT Lin- cells treated with LV.SF.LTR (N=25) or SIN.LV.PGK (N=24) vector have not developed tumors. Given this scenario, we expect that Cdkn2a-/- Lin- cells transduced with LV.SF.LTR are associated with higher mutation rates compared to the SIN.LV.PGK group and wild type control mice. The composition of peripheral blood, lymphoid (B and T) and myeloid compartments was assessed by FACS on samples collected every 4 weeks and IS identification. More than 200,000 IS have been recovered. To identify the presence of somatic mutations, the genomic portions of sequencing reads flanking each different IS were analyzed with VarScan2. The accumulation rates of mutations have been evaluated by our new Mutation Index (MI) which normalizes the number of mutations by clones and coverage. Considering that a large portion of IS has been discarded since not covered by a minimum number of 5 unique reads (genomes), the remaining number of IS contained >90% of reads in each group. The MI increased over time in both LV.SF.LTR groups, with higher values for the Cdkn2a-/-. On the other hand, treatment with SIN.LV.PGK resulted in lower MI in both groups compared to LV.SF.LTR groups, reflecting the higher clonal composition of the cells treated with the SIN.LV.PGK and the phenomenon of insertional mutagenesis in the LV.SF.LTR. Moreover, the higher MI values of the SIN.LV.PGK Cdkn2a-/- group compared with the WT group proved the induction of DNA fragility. Our results showed that the analysis of the accumulation of somatic mutations at single clone unraveled HSC proliferation stress in vivo, combining for the first time the analysis of acquired mutations with IS. We are now applying our model to different clinical trials, and studying HSCs sub- clonal trees by symmetric divisions, previously indistinguishable by IS only. Our study will open the doors to in vivo long-term non-invasive studies of HSC stability in patients

Holistic primary health care for Aboriginal and Torres Strait Islander prisoners: exploring the role of Aboriginal Community Controlled Health Organisations

© 2019 The Authors Objective: Aboriginal and Torres Strait Islander Community Controlled Health Organisations (ACCHOs) have been identified as having an important role in improving the health and wellbeing of individuals in prison; however, a lack of information exists on how to strengthen this role. This paper explores the experiences of ACCHO staff in primary health care to individuals inside or leaving prison. Methods: Nineteen staff from four ACCHOs were interviewed. ACCHO selection was informed by proximity to prisons, town size and/or Local Government Area offending rates. Thematic analysis of the interviews was undertaken. Results: While most ACCHOs had delivered post-release programs, primary health care delivery to prisoners was limited. Three themes emerged: i) a lack of access to prisoners; ii) limited funding to provide services to prisoners; and iii) the need for a team approach to primary health care delivery. Conclusion: A holistic model of care underpinned by a reliable funding model (including access to certain Medicare items) and consistent access to prisoners could strengthen ACCHOs’ role in primary health care delivery to people inside or leaving prison. Implications for public health: ACCHOs have an important role to play in the delivery of primary health care to prisoners. Existing models of care for prisoners should be examined to explore how this can occur

A study of gas contaminants and interaction with materials in RPC closed loop systems

Resistive Plate Counters (RPC) detectors at the Large Hadron Collider (LHC) experiments use gas recirculation systems to cope with large gas mixture volumes and costs. In this paper a long-term systematic study about gas purifiers, gas contaminants and detector performance is discussed. The study aims at measuring the lifetime of purifiers with unused and used cartridge material along with contaminants release in the gas system. During the data-taking the response of several RPC double-gap detectors was monitored in order to characterize the correlation between dark currents, filter status and gas contaminants