Immunological heterogeneity informs estimation of the durability of vaccine protection

Deciphering the properties of vaccines against an emerging pathogen is essential for optimizing immunization strategies. Early after vaccine roll-out, however, uncertainties about vaccine immunity raise the question of how much time is needed to estimate these properties, particularly the durability of vaccine protection. Here we designed a simulation study, based on a generic transmission model of vaccination, to simulate the impact of a breadth of vaccines with different mean (range: 10 months–2 years) and variability (coefficient of variation range: 50–100%) of the duration of protection. Focusing on the dynamics of SARS-CoV-2 in the year after start of mass immunization in Germany as a case study, we then assessed how confidently the duration of protection could be estimated under a range of epidemiological scenarios. We found that lower mean and higher heterogeneity facilitated estimation of the duration of vaccine protection. Across the vaccines tested, rapid waning and high heterogeneity permitted complete identification of the duration of protection; by contrast, slow waning and low heterogeneity allowed only estimation of the fraction of vaccinees with rapid loss of immunity. These findings suggest that limited epidemiological data can inform the duration of vaccine immunity. More generally, they highlight the need to carefully consider immunological heterogeneity when designing transmission models to evaluate vaccines.     

Soil organic matter in restored rangelands following cessation of rainfed cropping in a mountainous semi-arid landscape

Agricultural abandonment is known to influence plant cover composition and C inputs into the soil with a consequence for changes in soil organic matter (SOM) storage and dynamics in rangeland ecosystems. This study was conducted on a chronosequence of high altitude rangelands (1) cultivated with rainfed wheat (CR0), (2) abandoned for 4 (AR4), 12 (AR12) and 45 (AR45) years and (3) uncultivated (reference) rangelands (UR) with three replicates in Zagros Mountains, Central Iran. We studied the changes in the concentrations and stocks of bulk soil organic carbon (OC), total N, particulate organic C (POC) and N (PON), dissolved organic C (DOC), microbial biomass C (MBC), and potentially mineralizable C (Min-C) at 0–0.15 and 0.15–0.3 m soil depths. Results showed that the concentrations and stocks of OC, N, and labile fractions increased with the abandonment of agriculture at both soil sampling depths. After 4–45 years of agricultural abandonment, soil OC and N stocks increased logarithmically by 3.8–46 % and 2.8–32 % in the whole 0–0.3 m, respectively. Although, the stocks of labile fractions decreased slightly 4 years after agricultural abandonment, there were considerable increases (logarithmic) in these fractions after 12–45 years of abandonment (POC, 65–148 %; PON, 68–147 %; DOC, 76–139 %; MBC, 24–62 %). The study shows that rangelands abandoned for 45 years contained lower soil OC and N concentrations and stocks compared to uncultivated rangelands, reflecting 45 years of abandonment would not be sufficient for SOM to attain the level of uncultivated rangelands. The present study provided evidence that the rate of increases in POC and DOC stocks was greater than that of OC and MBC stocks, demonstrating POC and DOC fractions of total SOM pool may be suitable and sensitive indicators for detecting the effects of agricultural abandonment on soil OC changes and storage in these restored semi-arid rangelands. Soil bulk density decreased, while the mean weight diameter (MWD) and aggregate ratio as measures of aggregate stability increased considerably within the abandoned rangelands with increasing time of abandonment. Results from a multivariate analysis suggested that soil variables such as bulk density, OC, TN, DOC, POC, PON, MBC, MWD and metabolic quotient (qCO₂) were successful in separating land uses. In brief, the abandonment of agricultural activities in previously cultivated high altitude rangelands can potentially lead to an increase of total and labile SOM and also sequestration of C in these semi-arid rangelands.     

Response of a planar solid oxide fuel cell to step load and inlet flow temperature changes

To explore the dynamic characteristics of the SOFC systems and to develop relevant control strategies, a previously developed steady state SOFC model is converted to a dynamic model. The model includes mass, momentum, thermal and electrochemical analysis, as well as the kinetic model of hydrocarbon reactions. Applying two control strategies i.e., cell constant fuel flow rate and constant fuel utilization during the transient time, the model is implemented to analyse the dynamic behaviour of a planar direct internal reforming (DIR) SOFC cell under several step-load changes. Transient response, resulting from an inlet temperature variation, is also investigated. The results show that the relaxation time is strongly related to the thermal behaviour of the cell and the applied control strategy. However, it is almost independent of the load variation magnitude.     

Older Adults’ Physical Activity and Exergames: A Systematic Review

Exertion games, also referred to as exergames, have become popular because they combine physical activity (PA) with game mechanics, such as actions, challenges, and achievements. Exergames have been also used to encourage PA among older adults, as technological interventions to help achieve the latters’ health and wellness goals and as aids to rehabilitation. To the best of our knowledge, no systematic review of empirical studies on exergaming and older adults’ PA has been reported in the literature. Our review indicates that exergames make a measurable contribution to the improvement of health and wellness goals of older adults. Our systematic review identifies 9 categories and 19 themes of exergame applications in the domain of older adults’ PA. We aggregate these categories and themes into three broader exergaming clusters, of “training,” “rehabilitation,” and “wellness.” Additionally, we outline pathways for future empirical research into applying exergames as health and wellness interventions for older adults through physical activities.     

Inlay-inspired meta-piezoelectric plates for the low-frequency vibration energy harvesting

Journal of Materials Science: Materials in Electronics - Different novel auxetic geometries are proposed applicable for the low-frequency vibration energy harvesting. The geometrical idea...     

Vacuum vapour phase polymerization of high conductivity PEDOT: Role of PEG-PPG-PEG,the origin of water,and choice of oxidant

Vacuum vapour phase polymerization (VVPP) is a facile means of producing flexible PEDOT thin films having conductivities in excess of 1500 S cm^?1. The process is understood to utilize water as the effective proton scavenger during synthesis. The originating source of water, under vacuum condition however, was unknown. The location of the water within the oxidant solution was examined, with individual components desiccated and thermo-gravametric analysis (TGA) performed to ascertain the root source. The co-polymer PEG-PPG-PEG provides some water, while the majority originates from coordinated water associated with the iron tosylate oxidant, and from free water residing within the solvent carrier. Importantly, with the incorporation of the co-polymer water remains locked within the oxidant layer under vacuum and this allows the VVPP reaction to proceed without the need for an external water supply. Furthermore PEG-PPG-PEG serves the multi-functional role of inhibiting crystal formation within the oxidant layer, and reducing the effective reactivity of the oxidant. Finally, an examination of literature suggests that the choice of oxidant may depend on the type of VPP process used.     

On the differentiated QoE enforcement between competing scalable video flows over wireless networks

In differentiated quality‐of‐experience enforcement (QoE) for video transmission over wireless networks, accurate video quality metrics play a crucial role in the designing process of optimal resource assignment algorithms. Many cross‐layer optimization‐based rate‐allocation strategies, which consider different objective functions (congestion level, total packet loss, etc.), have been developed for this purpose. The main contributions of the proposed work are twofold. Firstly, an optimal resource assignment framework is being developed in which, based on some network‐specific constraints and by incorporating appropriate video quality metrics, the total weighted QoE of some competing scalable video sources is being optimized based on cross‐layer optimization techniques. Secondly, these optimal rates can be used for differentiated QoE enforcement between multiple competing scalable video sources. The resulting optimal rates can be considered as rate feedbacks for online rate adaptation of a moderate scalable video encoder such as H.264/MPEG‐4 advanced video coding. The aforementioned weight parameters are selected based on the importance of each video sequence's quality and can be associated with some previous service level agreement‐based prices. Some numerical analysis have been presented to validate the theoretical results and to verify the claims. Copyright © 2011 John Wiley & Sons, Ltd.     

Ultrathin Single Bilayer Separation Membranes Based on Hyperbranched Sulfonated Poly(aryleneoxindole)

The layer‐by‐layer method is an attractive technique for the fabrication of ultrathin nanostructured polyelectrolyte multilayer membranes (PEMM). A simple two‐step procedure is described here for the preparation of an ultrathin, nanostructured membrane comprising a 5–7 nm thick selective layer, consisting only of one single bilayer of poly(diallyldimethylammoniumchloride) and hyperbranched sulfonated poly(aryleneoxindole). These single bilayered membranes exhibit an outstanding solvent‐resistant nanofiltration performance, which is superior to that of commercial membranes as well as to previously reported multilayer membranes having 10–20 bilayers. A comparative study between hyperbranched polyelectrolyte (HPE) and linear polyelectrolyte supports the role of the specific 3D structure of the hyperbranched polyelectrolyte in these excellent separation properties. The work thus encompasses the use of HPEs as an ideal choice for PEMMs, which opens up a new route to significantly decrease the overall membrane preparation time while realizing excellent filtration properties.     

Near optimal conformal antenna array structure for direction‐of‐arrival estimation

This article determines the near optimal conformal antenna array structure for direction‐of‐arrival (DOA) estimation through a comprehensive study on the planar and usual conformal antenna arrays including the cylindrical and hemispherical by using the directive antenna elements in all designs. To model the hemispherical structure, an improved multi‐face antenna array with three different tilts is proposed and compared with previous works in order to investigate the tilt effect and obtain the conclusive results. The Cramer‐Rao lower bound, multiple signal classification, and root‐mean‐square error algorithms are utilized to evaluate the estimation accuracy of all conformal structures. Finally, by comparing the estimation precision of all conformal structures it is shown that the purposed multi‐face structure as the hemispherical model has a better performance than other conformal structures in terms of the maximum angular coverage of the spatial resource. Moreover, the proposed study method in this article fully examines the impacts of the different conformal antennas geometric structure on the DOA estimation performance by involving the directive antennas radiation patterns.