Search

Abstract Self-amplifying RNAs (saRNAs) are versatile vaccine platforms that take advantage of a viral RNA-dependent RNA polymerase (RdRp) to amplify the messenger RNA (mRNA) of an antigen of interest encoded within the backbone of the viral genome once inside the target cell. In recent years, more saRNA vaccines have been clinically tested with the hope of reducing the vaccination dose compared to the conventional mRNA approach. The use of N1-methyl-pseudouridine (1mΨ), which enhances RNA stability and reduces the innate immune response triggered by RNAs, is among the improvements included in the current mRNA vaccines. In the present study, we evaluated the effects of this modified nucleoside on various saRNA platforms based on different viruses. The results showed that different stages of the replication process were affected depending on the backbone virus. For TNCL, an insect virus of the Alphanodavirus genus, replication was impaired by poor recognition of viral RNA by RdRp. In contrast, the translation step was severely abrogated in coxsackievirus B3 (CVB3), a member of the Picornaviridae family. Finally, the effects of 1mΨ on Semliki forest virus (SFV), were not detrimental in in vitro studies, but no advantages were observed when immunogenicity was tested in vivo.

Abstract Research on concrete recycling has led to the discovery of many processes for recycled concrete aggregate (RCA) treatment, each with its pros and cons on quality improvement, resource requirements, or scalability. This study aimed to propose a technique that combines two methods (mechanical grinding and acidic soaking) for mortar removal and improves the quality of RCA so as to realize a zero-waste, highly efficient, few-hours-long single-step process which we call acid milling. A quantitative comparison of aggregate and final concrete quality has been performed between each separate method. The proposed method shows about 57% relative improvement of aggregate quality for water absorption and density, while the concrete experiment shows up to 10% relative improvement for the compressive and flexural strengths compared with the untreated RCA concrete. This study paves the way for an efficient and sustainable concrete recycling process to be applied on a large scale.

Abstract The regulation of cell behavior is crucial for understanding many fundamental biological processes and designing novel medical devices. Nano/micropatterning has been developed as a means of controlling cellular properties and behaviors. Using cinnamoyl groups that have undergone photodimerization, we have prepared facile photopatterning films with adjustable surface properties for cell patterning via simple steps. Our strategy for controlling surface properties uses the decrease in free volume induced by photocrosslinking. This paper describes the surface‐patterning properties of photocrosslinkable polymer films and the cell adhesion to their micropatterned surfaces. Upon culturing cells on micropatterned surfaces, preferential cell adhesion, alignment and proliferation are observed in the unexposed regions. Additionally, diverse surface patterns of photocrosslinkable polymer films have been fabricated using various photomasks, enabling effective control of cell adhesion and alignment. The ability to regulate cellular behavior via microfabricated surfaces of photocrosslinkable polymer films enables a new and facile approach for designing scaffolds for the development of novel advanced materials, tissue engineering, and regenerative medicine.

Abstract Background Helicopter Emergency Medical Services (HEMS) has been in operation in Japan since 2001, allowing patients almost anywhere in the nation to receive on-scene emergency treatment from physicians. However, there is insufficient literature on the characteristics of the patients who use Japanese HEMS. Thus, this study aimed to investigate the overall characteristics of patients receiving HEMS care within a single prefecture in Japan. Methods We retrospectively analyzed the data of 5163 patients—in Tochigi Prefecture—who received HEMS care from 2012 to 2019. Descriptive statistics were used to analyze the following aspects of care: diagnosis, severity, background characteristics, geographical and environmental variables, immediate pre-hospital intervention, transportation type, and short-term clinical outcomes. Results Among 7370 HEMS requests received during the study period, treatment was provided to 5163 patients (1.8 cases per day; 3489 men [67.6%]). Nearly 55% (n = 2856) of patients were aged above 60 years. Age peaks were observed at 0–9 years and 60–69 years. The median distance from the base hospital to the site was 26.7 km. The age-standardized rate of HEMS treatment was 30.3 patients per 100,000 people. Cases of trauma and cardiovascular diseases were the most common (65.3%). Most individuals aged 0–9 years and 60–69 years had neurological disease (seizures accounted for 80.5% of this group) and cardiovascular disease, respectively. The number of patients was similar across all four seasons. After immediate pre-hospital intervention, 81.6% of patients receiving HEMS care were transferred by the helicopter ambulance (53.4% and 28.2% to the base hospital and to other hospitals, respectively). Overall, 56.6% of patients receiving HEMS care were transferred to the base hospital, and the short-term recovery rate was above 75%. Intravenous drip and oxygen administration were the most common pre-hospital interventions (93.1% and 72.7%, respectively). Conclusions This study is the first to describe the overall characteristics of HEMS patients using comprehensive data of all HEMS patients in one prefecture in Japan. Further research using both local- and national-level data is needed to accelerate the understanding of the benefits of HEMS.

This paper aims to determine the effects of local corrosion at three different corrosion areas, the (1) entire area, (2) the constant moment area, and (3) the constant shear area, on the flexural performance of RC beams. To analyze this, an experimental study was carried out to prepare two series of RC beams (200 × 300 × 2800 mm) created with three different degrees of corrosion, inducing local rebar corrosion. Furthermore, two series of experimental tests were conducted under different loading types: monotonic and cyclic loading. It was observed that the strength capacity reduction grew in the RC specimens with induced corrosion in the order of the (1) entire area > (2) the constant moment area > (3) the constant shear area, as the average corrosion rate increased. Our test results further showed that the yield and ultimate strength were kept nearly equivalent to the uncorroded RC specimen, with average corrosion rates of 10% and 15%, respectively. Over these corrosion rates, the yield strength and ultimate strength dropped significantly. Compared to the test results under a monotonic loading condition, the structural capacity under a cyclic loading condition decreased, with a more pronounced tendency for each corrosion case as the corrosion rate increased. Longitudinal cracks developed throughout and adjacent to the corrosion areas as the corrosion rate increased. Thus, we can infer that strength reductions may be strongly influenced by these longitudinal cracks.

Abstract In this paper, we analyze the corrosion of reinforcements as indices of processes of the super‐long‐term combined deterioration of reinforced concrete building groups with finishing materials, pre‐induced cracks, and maintenance. Specifically, we systemize specifications for finishing materials by permeability, deterioration mechanisms, and demeanor after repairs, and adopt agent‐based modeling for decision‐making of specifications for structures, finishing materials, and repair methods whose characteristics are based on generic products. We calculate the corrosion of reinforcements in general parts by Yonezawa's method and in cracks by the corrosion speed of bare steel, and assume minimum corrosion amounts required to initiate new cracks by Morinaga's method in consideration of corrosion amounts to fill up voids around reinforcements. We analyze the deterioration processes of building groups by using three scenarios with several histories of preferences of building owners based on ISO 19208. It is confirmed that the averages of acceleration‐period arrival rates in the group vary in line with the characteristics of each scenario and are lower than the repair limits for each preference and half of the 3% upper‐confidence limits. Although this method is embryonic, we quantitatively and theoretically demonstrate the super‐long‐term combined deterioration processes of the building group.

Background: Clostridium perfringens and Shiga toxin (Stx)-producing Escherichia coli (STEC) are common causes of food poisoning. We previously demonstrated the efficacy of Stx2B-C-CPE, a fusion protein of the C-terminal region of C. perfringens enterotoxin (C-CPE) and Shiga toxin 2 B subunit (Stx2B), as a bivalent vaccine against C. perfringens and STEC infections. Methods: Here, we applied an E. coli expression system and Triton X-114 phase separation to prepare tag- and endotoxin-free Stx2B-C-CPE for use in vaccine formulations. Results: As we anticipated, endotoxin removal from the purified antigen reduced both Stx2B- and C-CPE-specific IgG antibody responses in subcutaneously immunized mice, suggesting that endotoxin contamination influences the immunological assessment of Stx2B-C-CPE. However, the combined use of aluminum and Alcaligenes lipid A adjuvants improved IgG antibody responses to the injected antigen, thus indicating the suitability of purified Stx2B-C-CPE for vaccine formulation. Conclusions: Our current findings provide important knowledge regarding the design of an effective commercial Stx2B-C-CPE vaccine.

The significant contribution of Portland cement in the global climate change, and the common durability issues of Portland cement concrete have led to develop geopolymer cement as an alternative to traditional Portland cement for creating a concrete that’s more sustainable and durable. The factors that significantly affect the strength and flowability of Geopolymer binder material are presented in this investigation. The factors considered are fly ash content of (400-600) kg/m3, alkali to fly ash ratio from 0.4 to 0.6 in increment of 0.5, sodium hydroxide concentration of 8 M to 16 M in increment of 2 M, and sodium silicate to sodium hydroxide solution ratio of 1 to 3 in increment of 0.5. The results obtained show that increasing NaOH concentration would increase the flowability and strength of geopolymer binder while increasing alkali to fly ash ratio decreased the compressive strength of the geopolymer binder. Increasing fly ash content and sodium silicate to sodium hydroxide solutions ratio increased the flowability but decreased the compressive strength.

The reaction of natural pozzolans is caused by volcanic glass composed of amorphous silicate; however, volcanic ejecta also contains crystal mineral, pumice, and sometimes weathered clay fraction in their natural conditions. By focusing on the differences of physical properties between these components, high-purity volcanic glass powder (VGP) was manufactured by dry gravity classification and pulverization. This paper reports the results of investigations to utilize pyroclastic flow deposits as a supplementary cementitious material (SCM). Through this method, the glass content of VGP increased to 88% with a mean particle size of 1 μm, when that of the raw material is about 60%. Chemical analysis indicated that VGP is principally composed of silica (about 72%) and alumina (about 13%). The performance of VGP as a SCM was evaluated by conducting tests on concrete mixtures, replacing 0% to 30% by weight of portland cement by VGP with a 20% to 60% water to cement ratio. VGP concrete showed better results of 7-and 28-day compressive strength compared to control concrete in all experiments. In particular, VGP demonstrated better flowability and strength development in concrete with a low water-binder ratio in comparison to silica fume.

Efficient maintenance and upgrading of a building during its lifecycle are difficult because a cementitious finish uses materials and parts with low disassembly properties. Additionally, the reuse and recycling processes during building demolition also present numerous problems from the perspective of environmental technology. In this study, an induction heating (IH) method was used to disassemble cementitious finish joints, which are widely used to join building members and materials. The IH rapidly and selectively heated and weakened these joints. The temperature elevation characteristics of the cementitious joint materials were measured as a function of several resistor types, including wire meshes and punching metals, which are usually used for cementitious finishing. The disassembly properties were evaluated through various tests using conductive resistors in cementitious joints such as mortar. When steel fiber, punching metal, and wire mesh were used as conductive resistors, the cementitious modifiers could be weakened within 30 s. Cementitious joints with conductive resistors also showed complete disassembly with little residual bond strength.

The aim of this work is to know clearly the effects of temperature in response to curing condition, hydration heat, and outside weather conditions on the strength development of high-performance concrete. The concrete walls were designed using three different sizes and three different types of concrete. The experiments were conducted under typical summer and winter weather conditions. Temperature histories at different locations in the walls were recorded and the strength developments of concrete at those locations were measured. The main factors investigated that influence the strength developments of the obtained samples were the bound water contents, the hydration products, and the pore structure. Testing results indicated that the elevated summer temperatures did not affect the early-age strength gain of concrete made using ordinary Portland cement. Strength development was significantly increased at early ages in concrete made using belite-rich Portland cement or with the addition of fly ash. The elevated temperatures resulted in a long-term strength loss in both belite-rich and fly ash containing concrete. The long-term strength loss was caused by a reduction in the degree of hydration and an increase in the total porosity and amount of smaller pores in the material.

Ocean thermal energy conversion (OTEC) harvests the power from the thermal energy in the ocean, which is reserved in the ocean as the temperature difference between warm surface and cold deep seawaters. In the energy conversion, the heat exchangers transfer the thermal energy to the heat engine, which converts it into power. The pressure drops yielded by piping, valve and heat exchangers cause pump loads, which show significant negative power with respect to net power in OTEC. The heat transfer performance and the pressure drop in heat exchanger depend on the types and shapes of each heat transfer area. Generally, heat exchangers with higher friction factors yield higher heat transfer performance and vice versa. However, heat transfer performance and pressure drop are separately evaluated and there is no comprehensive performance evaluation index for OTEC power take-off. Therefore, this research proposes a new simplified overall performance evaluation method for heat exchangers, which can be comprehensively and easily applied and takes into consideration the heat transfer performance and the pressure drop. The evaluation results on plate-type heat exchangers show that the overall performance in each heat exchanger are elucidated and are quantitatively compared.

Using ground granulated blast-furnace slag (GGBS) under different alkaline conditions, we studied the mechanisms and extents of Cr(VI) reduction and sorption and compared them to reactions with Portland cement (PC). We also investigated the effects of mixing PC/GGBS ratios on Cr(VI) dissolution after carbonating the substrates. We observed a complete sorption and reduction of Cr(VI) to Cr(III) in a GGBS-in-Ca(OH)2 solution (pH > ~12.5) after 10 h, whereas in distilled water (pH = ~11.5) GGBS exhibited only marginal sorption and reduction (20%). Cr reactions with dissolved ions in supernatants derived from GGBS indicated that the anions dissolved from GGBS act as a reducing agent for Cr(VI) in a Ca(OH)2 solution. Soft X-ray absorption microscopy identified a partial reduction of Cr(VI) to Cr(III) on the GGBS surface. The carbonation of pure PC paste substantially increased the amount of dissolved Cr(VI) in a solution phase whereas a 5 wt % replacement of PC with GGBS significantly reduced the amount of dissolved Cr(VI). We concluded that in the mixed paste during the early curing stage GGBS reduced a significant fraction of Cr(VI) to Cr(III) and that the Cr(III) adsorbed in the GGBS-PC mixture’s hydration products does not readily dissolve, even under carbonation conditions.