The microenvironment of solid tumors is very challenging for anti-tumor T cells. Low oxygen, low pH, inhibitory signals (e.g. cell surface receptors, metabolites, lipids), and high intratumoral ...pressure drive infiltrating T cells toward inhibition, exhaustion and death. Improved T cell fitness in this environment is critical to efficacious and durable T-cell therapies. The goal of this work is to improve the fitness of therapeutic T cells in the tumor microenvironment by changing the conditions under which a T-cell therapy is manufactured. To do this, we utilized a low-oxygen, high-pressure environment created by the Avatar incubator system during a small-scale non-viral editing process to generate TCR-T cells with a metabolic program that improves their fitness and potency in the harsh TME.
We assessed changes to T cell phenotype, function, and metabolic state during this manufacturing process. Not only did the T cells expand more rapidly in the low oxygen, high pressure conditions in the Avatar, flow cytometric analysis revealed a phenotypic shift in the cells toward an increasing Teff to Tscm ratio across multiple donors. Notably, while cells conditioned for 14 days in the Avatar exhibit a reduced Spare Respiratory Capacity (SRC) and a greater reliance on glycolytic metabolism, the final cell product demonstrated improved potency as indicated by tumor cell killing at lower effector-to-target ratios compared to cells cultured under ambient oxygen and normal atmospheric pressure. Generating a T-cell therapy with higher fitness in the TME by modulating the process environment during GMP manufacturing with a system like the Avatar, or the GMP-ready Foundry, has the potential to improve the efficacy of T-cell therapies in patients.
Proton exchange membrane water electrolyzers (PEMWEs) driven by renewable electricity provide a facile path toward green hydrogen production, which is critical for establishing a sustainable hydrogen ...society. The high working potential and the corrosive environment pose severe challenges for developing highly active and durable electrocatalysts for the oxygen evolution reaction (OER). To date, iridium (Ir)‐based materials, largely metallic Ir and Ir‐based oxides, are the most suitable OER electrocatalysts for PEMWEs due to their balanced activity and durability. Tremendous efforts have been devoted to improving the specific activity of Ir species to reduce the cost; however, advances in enhancing the durability of Ir‐based electrocatalysts are rather limited. In this review, the recent research progress on tackling the stability issues of Ir‐based OER electrocatalysts in acid media is summarized, aiming to provide inspiration for designing highly active and stable Ir‐based electrocatalysts. The OER mechanism and the associated failure modes of active Ir species are summarized. Then, mechanistic studies on the dissolution behavior of Ir species and experimental attempts on enhancing the durability of Ir‐based electrocatalysts are discussed. The personal perspectives for future studies on Ir‐based OER electrocatalysts are also provided.
The durability of iridium (Ir)‐based electrocatalysts is critical to proton exchange membrane water electrolyzers, but current studies are not adequate. Herein, the durability issues of Ir‐based oxygen evolution reaction electrocatalysts in acid media are reviewed with a focus on the dissolution behavior of active Ir species, aiming to provide inspiration for the future development of Ir‐based electrocatalysts.
Transition metal oxides (TMOs) have attracted considerable attention owing to their strong anchoring ability and natural abundance. However, their single‐site adsorption toward sulfur (S) species ...significantly lowers the possibility of S species reacting with Li+ in the electrolyte and increases the reaction barrier. This study investigates molecular modification by coupling the TMO structure with Li+ conductive polymer ligands, and vanadyl ethylene glycolate (VEG) is successfully synthesized by introducing organic ligands into the VOx crystal structure. In addition to the strong interaction between the VOx and lithium polysulfides via the V–S bond, the groups in the VEG polymer ligands can reversibly couple/decouple with Li+ in the electrolyte. Such dual‐site adsorption enables a smooth dynamic adsorption‐diffusion process. Accordingly, the VEG‐based Li–S cells exhibit excellent rate reversibility, cyclic stability, and a long cycle life without the addition of conducting agents. Encouragingly, the VEG‐based cells also exhibit close and excellent capacity decays of 0.081%, 0.078%, and 0.095% at 0, 25, and 50 °C (1 C for 200 cycles), respectively. This work provides a novel approach for developing advanced catalysts that can realize Li–S batteries with long‐term durability, fast charge‐discharge properties, and applications in a wide temperature range.
Dual‐site adsorption‐catalytic conversion! Dual‐site adsorption enabled by V and adjacent O sites via V–S and Li–O reduces the distance between S species and Li+ to nearly the interatomic distance, which significantly improves the anchoring efficiency and catalytic activity during the conversion of LiPSs. Therefore, excellent electrochemical performance can be achieved over a wide range of temperatures.
•Structural concrete with fine and coarse recycled concrete aggregates (RCA) was studied.•RCA of different origins were used: from real waste and produced in laboratory.•The mechanical, durability ...and long-term performance of concrete with RCA was analysed.•Similar performances using different RCA can be achieved.•Total incorporation of RCA in the production of structural concrete is deemed possible.
This investigation intends to analyse the effects of the variation of different types of recycled concrete aggregates (RCA) on structural concrete. For this purpose, two source concrete (SC) mixes, one produced in the laboratory and another in a precasting plant, were considered. The experimental campaign included mechanical, durability and long-term tests: compressive strength in cubes; splitting tensile strength; modulus of elasticity; abrasion resistance; water absorption by immersion and by capillarity; resistance to carbonation; resistance to chloride ion penetration; shrinkage and creep. The recycled aggregate concrete (RAC) mixes were compared with a reference concrete (RC) produced solely with natural aggregates (NA). Concerning the replacement percentages for fine and coarse recycled concrete aggregates (FRCA/CRCA%), the following were considered: 25/25; 50/50; 100/0; 0/100 and 100/100%. The results show that it is possible to achieve similar performances using RCA from different SC but with similar compressive strengths. In fact, RAC mixes achieved results comparable to RC in several properties.
•A comprehensive review of the fundamental factors influencing the tensile properties of ECC was conducted.•The durability of ECC including the long-term tensile properties, the impact of high ...temperature, cyclic and fatigue loading was reviewed.•The future directions of ECC have been pointed out.
The high tensile strain capacity of engineered cementitious composites (ECC) is exceptional for cementitious material. In the present paper, a comprehensive review is conducted to summarize the fundamental information of factors that influence the tensile properties of ECC, specifically the fiber properties, specimen size and geometry, and strain rate. The extended durability of ECC, including the long-term tensile properties, the mechanical behaviors under the high temperature impact and the cyclic and fatigue loading, is also paid special attention. It is concluded that (1) fiber properties have a decisive effect on the tensile performance of ECC; (2) size and geometry effect exists in tensile test and needs further study; (3) high rate loading leads to a noticeable changes in the tensile properties of ECC; and (4) durability of tensile properties should be further investigated for the better application of ECC material.
•Recycled Concrete Aggregate (RCA) is a future material towards sustainable development.•Properties of Recycled Aggregate Concrete (RAC) and its performances are comprehensively documented.•Advanced ...mixing approaches and incorporation of mineral additives for improving the properties of RAC.
The ever increasing population and urbanization has led to construction of high rise structures and demolishing existing old low rise ones. This has become not only the cause of natural resources depletion at an alarming rate but also gradually becoming a challenge for sustainability. Concrete industry consumes a majority of natural resources especially in developing countries. In recent years the concrete industry has started using Construction and Demolition (C&D) waste in structural concrete application owing to the availability of waste from demolition of old structures and the reduction in cost of acquiring aggregates. This can allow the concrete industry to reduce its carbon footprint and thus help it to continue to grow without harming the environment. In this backdrop, this paper provides an account of properties of concrete prepared with recycled aggregate, analyses the important findings on Recycled Aggregate Concrete (RAC) in the recent time and discusses the suitability of its usage in construction. The open literature suggests that the durability and mechanical properties of RAC is slightly inferior than that of conventional concrete. However, with the use of admixtures and modified mixing approaches, the desired properties of RAC can be obtained. Collation and analysis of more than 200 research papers in this area on various facts of Recycled Aggregate Concrete, on one hand, may be considered as a step ahead for formation of design methodology and, on the other hand, a valuable stating document for further research.
AbstractMicrobially induced calcite precipitation (MICP) is a sustainable biological ground improvement technology that is capable of improving the engineering properties of soil. A laboratory study ...was conducted to investigate the influence of some key environmental parameters on the long-term engineering performance of MICP-treated sandy soil, including wet-dry cycles, freeze-thaw cycles, and acid rain conditions, and to study the effect of enhancement through fiber reinforcement and multiple MICP treatments. Experimental results indicated that durability of MICP-treated soil was weak in wet-dry cycles, freeze-thaw cycles, and acid rain conditions. The unconfined compression strength (UCS) of MICP-treated soil had nearly 80% reduction after one wet-dry cycle, 58% reduction after 15 freeze-thaw cycles, and 83% reduction after 15 days immersed in acid rain solution with the pH of 3.5. Fiber reinforcement mainly enhanced the ductility of MICP-treated samples. The failure strain of fiber-reinforced samples reached 1.6% compared with unreinforced samples of 0.4% after 5 wet-dry cycles. Multiple treatments enhanced the durability of MICP-treated samples. The UCS of multiple MICP-treated samples had no significant reduction after wet-dry and freeze-thaw cycles. For quadruple MICP-treated samples, a 51.9% UCS still remained after 15 days immersed in acid rain solution with the pH of 3.5.
Concrete infrastructure repair remains a formidable challenge. We need to understand the repair performance and develop innovative materials and placement processes that lead to durable, ...cost-effective and esthetically pleasing repairs. In this context, fiber reinforced concrete is considered promising.
The influence of fibers on the properties of the interface between old concrete and fiber reinforced repair remains poorly understood. This paper describes an experimental study on the influence of fibers on the mechanical properties of the interface. Bond strength was assessed by means of slant shear tests with different slants. Shear-normal stress interaction diagrams, adhesion strength and internal friction were obtained. Repair mortars with different contents of Polyvinyl Alcohol (PVA) fibers and the influence of wet–dry cycles were investigated.
Results show that PVA fibers added to the repair can significantly enhance interfacial adhesion. Once the repair interface is fully developed, fibers, however, do not mitigate damage from wetting and drying.
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