QoS-RRC: an overprovisioning-centric and load balance-aided solution for future internet QoS-oriented routing

The concepts and designs of 4WARD project for the Future Internet involve a clean-slate architecture with various networking innovations, including a new connectivity paradigm called Generic Path (GP). In GP architecture, several facilities are designed to efficiently support complex value-added applications and services with assured Quality of Service (QoS). The GP mainly makes transparent the underlying network structure and heterogeneity, and any entities, regardless of their purpose (technology, location or architectural layer) communicate with each other in a single way via a common interface. In addition, cooperation with network-layer provisioning mechanisms is required to map data paths that are compliant with session-demanded resources (QoS requirements - minimum bandwidth and maximum delay/loss experience) in appropriate GPs. In contrast, robust and scalable QoS-provisioning facilities are urgently required as a support for efficient GP allocations. To address this need, this paper introduces the QoS-Routing and Resource Control (QoS-RRC), a set of GP-compliant facilities to meet the requirements mentioned above. QoS-RRC complements GP architecture with QoS-oriented routing, with the aid of load balancing to select paths that comply with session-demands while keeping residual bandwidth to increase user experience. To address scalability issues, QoS-RRC operates on the basis of an overprovisioning-centric approach to achieve cost-effectiveness in terms of state storage, signaling load and network operations. An initial QoS-RRC performance evaluation was carried out in Network Simulator v.2 (NS-2), which showed that there had been drastic improvements in the flow delay experience and bandwidth use among a range of relevant state-of-the-art solutions. Moreover, the impact of QoS-RRC on the user experience (compared to current IP QoS and routing standards) has been evaluated, by analyzing the main objective and subjective Quality of Experience (QoE) metrics, namely Peak Signal to Noise Ratio (PSNR), The Structural Similarity Index (SSIM), Video Quality Metric (VQM) and Mean Opinion Score (MOS).     

Chitosan/clay films' properties as affected by biopolymer and clay micro/nanoparticles' concentrations

Blends of chitosan (from Cuban lobster) and clay micro/nanoparticles were prepared by dispersion of the clay particles in the film matrix and the films obtained were characterized in terms of water solubility, water vapor, oxygen and carbon dioxide permeability, optical, mechanical and thermal properties using an Instron universal testing machine, differential scanning calorimetry, thermogravimetric analyses and scanning electron microscopy (SEM). The water vapor barrier properties of the films were significantly improved by incorporation of clay in their composition, while the water solubility decreased as the clay concentration increased (for a constant chitosan concentration). The tensile strength of chitosan/clay films increased significantly with increasing chitosan and clay concentrations, while the values of elongation decreased slightly for high values of chitosan concentration. T_m increased with the increase of chitosan concentration, but the changes in T_m with the addition of clay were not significant.Polynomial models were fitted to the experimental data in order to facilitate future design of chitosan/clay film systems.     

A new use for glassy carbon: Development of LDPE/glassy carbon composites for antistatic packaging applications

Antistatic packaging is used for the protection and storage of electronic boards and sensitive electronic components. Different polyolefins can be used for the production of antistatic packaging; however, the accumulation of static electricity in these polyolefins may cause serious damage to the electronic components. In this study, since glassy carbon (GC) has good mechanical properties and electrical characteristics, it was used as an antistatic filler and blended with low-density polyethylene (LDPE). Composites of LDPE with GC in different proportions were prepared in the molten state using a homogenizer rotating at 3000 rpm. The composites were characterized in terms of thermal, mechanical, structural, and electrical properties. The GC is well dispersed and distributed in the LDPE, which contributed to the formation of a percolated network that enhanced antistatic characteristic. An increase of two orders of magnitudes in the electrical conductivity was obtained for the composite with 0.5 wt % of GC and thus it can be used as antistatic packaging. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47204.     

Prehospital-initiated vs hospital-initiated thrombolytic therapy. The Myocardial Infarction Triage and Intervention Trial

OBJECTIVE: To determine the effect of prehospital-initiated vs hospital-initiated treatment of myocardial infarction on clinical outcome. DESIGN: Randomized, controlled clinical trial. SETTING: Multicenter study involving 19 hospitals and all paramedic systems in the Seattle, Wash, metropolitan area. PATIENTS: A total of 360 patients with symptoms for 6 hours or less, no risk factors for serious bleeding, and ST-segment elevation were selected by paramedics and a remote physician for inclusion into the trial. They represented 4% of patients with chest pain who were screened and 21% of those with acute infarction. INTERVENTIONS: Patients were allocated to have aspirin and alteplase treatment initiated before or after hospital arrival. Intravenous sodium heparin was administered to both groups in the hospital. MAIN OUTCOME MEASURE: The primary endpoint was a ranked composite score (combining death, stroke, serious bleeding, and infarct size). The relation between time to treatment and outcome (composite score, infarct size, ejection fraction, and mortality) was also assessed. RESULTS: Initiating treatment before hospital arrival decreased the interval from symptom onset to treatment from 110 to 77 minutes (P < .001). Although more patients whose therapy was initiated before hospital arrival had resolution of pain by admission (23% vs 7%; P < .001), there were no significant differences in the composite score (P = .64), mortality (5.7% vs 8.1%), ejection fraction (53% vs 54%), or infarct size (6.1% vs 6.5%). A secondary analysis of time to treatment and outcome showed that treatment initiated within 70 minutes of symptom onset was associated with better outcome (composite score, P = .009; mortality, 1.2% vs 8.7%, P = .04; infarct size, 4.9% vs 11.2%, P < .001; and ejection fraction, 53% vs 49%, P = .03) than later treatment. Identification of patients eligible for thrombolysis by paramedics reduced the hospital treatment time from 60 minutes (for patients not in the study) to 20 minutes (for study patients allocated to begin treatment in the hospital). CONCLUSION: There was no improvement in outcome associated with initiating treatment before hospital arrival; however, treatment within 70 minutes of symptom onset--whether in the hospital or in the field--minimized the infarct process and its complications.     

High sinterability of Ca-PZT, synthesized by polymeric and partial oxalate process

This study includes Ca-PZT in the morphotropic phase boundary, MPB process combining the Pechini method, (ZT) and the Partial oxalate method (Ca-PZT) by obtaining single phase particles of ZT phase with a high specific surface area (110 m²/g at 550° C) and narrow particle size distribution. Lead and calcium oxalates were precipitated onto the ZT particle surface and reacted to a solid state interface ZT/Ca-PZT/PbO-CaO. A deviation of a coexistence region from F_T- and F_R-phases to F_R-phase (Zr rich region) was observed. Strong surface area reduction occurs by Ca-PZT crystallization at about 700°C, and demonstrated high sinterability (2.40 m²/g – 350 nm) with apparent densities near to 99.9%. Different processing methods did not demonstrate superior results. Studies of calcined powder shows a high sinterability of powder calcined 3 h at 700° C and sintered 3 h at 1000°C coming up to 99.8% of relative density.     

Effect of the Soldering Atmosphere on the Wettability Between Sn4.0Ag0.5Cu (in wt.%) Lead-Free Solder Paste and Various Substrates

The “degree of wetting,” which is related to the contact angle (θ) between the molten solder and the substrate, is a useful parameter on the solderability process control. The contact angle, however, is strongly dependent on the type of substrate surface finish and used atmosphere (inert or non-inert). Furthermore, the surface tension, being an important parameter on the solderability process and performance, can also be achieved if the contact angle is known. In this study, the SAC405 [Sn4.0Ag0.5Cu (in wt.%)] solder paste contact angle was measured, by the “sessile drop” method, as a function of the temperature, surface pad finish and used atmosphere. The results are discussed, and the contact angles obtained for the different conditions are compared and discussed. Then, the surface tension (experimental) was obtained from the measured contact angle and compared with the obtained by using computation models (theoretical). The experiments performed in high vacuum conditions, i.e., low oxygen content, over a temperature range, allowed the evaluation and understanding of the surface oxides layers role on the solder wettability. The present study shows that in the soldering process, even in an inert atmosphere, usually used in industry, occurs the formation of superficial oxides, over the liquid solder and/or at the pad surfaces, that strongly affects the solder paste wettability, specially with Sn and OSP (organic solderability preservative) finishing. Differences in contact angle of ≥?10° were determined between the two types of used atmospheres. The experimental surface tension and theoretical surface tension obtained, for the NiAu substrate type, present good correlation. The lower contact angle values were obtained for the NiAu and OSP finish types, independently of the atmosphere type.     

Glass fiber/carbon nanotubes/epoxy three‐component composites as radar absorbing materials

The use of micro or nano‐fillers to optimize the properties of epoxy resins has become a common practice. The Carbon nanotubes (CNT) are considered excellent fillers because of their strength, stiffness, thermal conductivity, electrical capacity, and thermal stability, along with large electromagnetic wave absorption capability in the microwave range. In this work, electromagnetic absorption properties and dynamic‐mechanical response obtained with the incorporation of CNT into glass fiber/epoxy composites have been studied. A novel procedure to disperse and deposit CNT onto glass fiber fabrics has been developed to reach high overall content of CNT in the composite (4.15 wt%). Storage modulus increased with the incorporation of CNT, especially when they had also been incorporated into the epoxy, and for higher frequency (3 Hz). The response of the composites to electromagnetic radiation has shown an increasing trend for higher CNT content (up to 2 wt%), reaching an excellent attenuation value of up to −18.3 dB (98.5% of absorption). POLYM. COMPOS., 37:2277–2284, 2016. © 2015 Society of Plastics Engineers     

Effect of an Edible Nanomultilayer Coating by Electrostatic Self-Assembly on the Shelf Life of Fresh-Cut Mangoes

This work aims at evaluating the effect of an alginate-chitosan nanomultilayer coating, obtained by electrostatic layer-by-layer self-assembling, in the quality and shelf life of fresh-cut mangoes. Coated and uncoated fresh-cut mangoes were stored under refrigeration (8 °C) for 14 days. The changes in mass loss, titratable acidity, pH, ascorbic acid content, total soluble solids, malondialdehyde content, browning rate, and microbial count were evaluated during storage. At the end of the storage period, lower values of mass loss, pH, malondialdehyde content, browning rate, soluble solids, microorganisms’ proliferation, and higher titratable acidity were observed in the coated mangoes. The nanomultilayer coating did not improve the retention of vitamin C during storage of fresh-cut mangoes. Results suggest that chitosan-alginate nanomultilayer edible coating extends the shelf life of fresh-cut mangoes up to 8 days.     

Impacts of a delayed and slow-paced vaccination on cases and deaths during the COVID-19 pandemic: a modelling study

In Brazil, vaccination has always cut across party political and ideological lines, which has delayed its start and brought the whole process into disrepute. Such divergences put the immunization of the population in the background and create additional hurdles beyond the pandemic, mistrust and scepticism over vaccines. We conduct a mathematical modelling study to analyse the impacts of late vaccination along with slowly increasing coverage, as well as how harmful it would be if part of the population refused to get vaccinated or missed the second dose. We analyse data from confirmed cases, deaths and vaccination in the state of Rio de Janeiro in the period between 10 March 2020 and 27 October 2021. We estimate that if the start of vaccination had been 30 days earlier, combined with efforts to drive vaccination rates up, about 31 657 deaths could have been avoided. In addition, the slow pace of vaccination and the low demand for the second dose could cause a resurgence of cases as early as 2022. Even when reaching the expected vaccination coverage for the first dose, it is still challenging to increase adherence to the second dose and maintain a high vaccination rate to avoid new outbreaks.     

Assessment of the Antibiofilm Performance of Chitosan-Based Surfaces in Marine Environments

Marine biofouling is a natural process often associated with biofilm formation on submerged surfaces, creating a massive economic and ecological burden. Although several antifouling paints have been used to prevent biofouling, growing ecological concerns emphasize the need to develop new and environmentally friendly antifouling approaches such as bio-based coatings. Chitosan (CS) is a natural polymer that has been widely used due to its outstanding biological properties, including non-toxicity and antimicrobial activity. This work aims to produce and characterize poly (lactic acid) (PLA)-CS surfaces with CS of different molecular weight (Mw) at different concentrations for application in marine paints. Loligo opalescens pens, a waste from the fishery industry, were used as a CS source. The antimicrobial activity of the CS and CS-functionalized surfaces was assessed against Cobetia marina, a model proteobacterium for marine biofouling. Results demonstrate that CS targets the bacterial cell membrane, and PLA-CS surfaces were able to reduce the number of culturable cells up to 68% compared to control, with this activity dependent on CS Mw. The antifouling performance was corroborated by Optical Coherence Tomography since PLA-CS surfaces reduced the biofilm thickness by up to 36%, as well as the percentage and size of biofilm empty spaces. Overall, CS coatings showed to be a promising approach to reducing biofouling in marine environments mimicked in this work, contributing to the valorization of fishing waste and encouraging further research on this topic.