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CO 2 -based biodegradable plastics are potential solutions for reducing fossil-fuel consumption, mitigating climate change, and addressing plastic pollution by reducing plastic waste accumulation. Poly(propylene carbonate) (PPC) is a commercial CO 2 -based biodegradable plastic derived from CO 2 and propylene oxide (PO), and it has been used in flexible packaging and mulching film applications. However, the environmental performance of PPC is still unknown. Since China has become the largest producer of PPC in the world, this study takes the industrial production technologies of PPC and its feedstocks in China as an example. The cradle-to-gate life-cycle inventory of PPC resin was compiled, and life-cycle impact assessment was performed to assess the environmental impacts of PPC and mitigation potentials based on the ReCiPe 2016 method. Results indicated that PPC synthesis has the greatest impact on the environment (contributions of 38–95% of 16 environmental impact categories), followed by PO production. Technological innovation and renewable energy substitution scenarios were developed to explore the mitigation potential of PPC. We found that supercritical polymerization technology has greater mitigation potential than photovoltaic power substitution, which could reduce 17 impact categories of PPC by 17–96% by reducing energy and dichloromethane consumption during PPC synthesis. Photovoltaic power substitution reduced 2–22% of 11 impact categories of PPC. Compared with conventional plastics, PPC had advantages over conventional plastics in terms of 17 impact categories. The environmental impacts of PPC were 2–98% lower than those of conventional plastics. This study emphasizes the importance of technological innovation in reducing the lifecycle environmental impacts of PPC and provides a basis for environmental performance of CO 2 -based biodegradable plastics and the potential to replace conventional plastics. Policy implications for innovations in synthesis technology, sustainable feedstocks and environmental impact assessment were proposed, which could provide valuable insights for practitioners and policymakers in enhancing the sustainability of the plastics industry through biodegradable plastic alternatives. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] As the fourth state of matter, plasma's unique properties and interactions with other states of matter offer many promising opportunities for investigation and discovery. In particular, cold atmospheric plasma (CAP), operating at atmospheric pressure and room temperature, has remarkable potential for biomedical applications through various delivery methods. These biomedical applications include sterilization, wound healing, blood coagulation, oral/dental diseases treatment, cancer therapy, and immunotherapy. Effective delivery of plasma constituents is critical to its efficacy for these applications. Therefore, this review presents the key research activities related to CAP delivery (including direct CAP delivery, delivery of plasma-activated media, biomedical device-assisted plasma delivery, and CAP delivery with other therapeutics) and needs for future research. This review will be of great interest for understanding the current state-of-the-art of biomedical applications of plasma medicine while also giving researchers from a broad range of communities insight into research efforts that would benefit from their contributions. Such communities include biomedicine, physics, biochemistry, material science, nanotechnology, and medical device manufacturing. [ABSTRACT FROM AUTHOR]

The Tibetan Empire, the only united regime in Tibetan history, existed between 618 and 877 CE, when Tibet was a unified world power, contesting control of Central Asia with the Tang Empire and the Abbasid Caliphate. Before its collapse in the 9th century, this was the world's highest elevation empire, ruling a vast territory that extended well beyond the Tibetan Plateau. However, factors leading to the rapid decline of this powerful highland empire remain elusive. Here we use a highly resolved lake sediment record from the western Tibetan Plateau to demonstrate that pronounced fluctuations in the climate regime between the 7th and 9th centuries played a key role in the fragmentation of the Tibetan Empire. Specifically, we demonstrate that a nearly complete shift from planktonic to benthic diatom life strategy signified markedly drier conditions and lower lake-levels. The height of the empire's power (ca. 600–800 CE) coincided with two centuries of uncharacteristically warm and humid conditions, whereas the empire's collapse (ca. 800–877 CE) co-occurred with an abrupt onset of severe drought conditions that were clearly registered in the paleolimnological records. Severe drought conditions combined with decreased social resilience might have led to rapid declines in crop production, which fostered a surge in domestic conflicts and expediated the final collapse of the Tibetan Empire. Although religious and political factors are commonly cited to explain the fall of this formidable great power, our paleoenvironmental analyses underscore that harsh environmental factors might have hastened the cultural decline of this highland region. • Paleolimnological data from a rare freshwater lake in the western Tibetan Plateau. • Abrupt collapse of the Tibetan Empire around 9th century linked to severe drought. • Rise and fall of empire linked to marked climate shifts between 7th and 9th centuries. • These changes were detrimental to the political unity of the Tibetan Plateau. • Diatoms closely tracked changes in lake level. [ABSTRACT FROM AUTHOR]

• Presents an indirect evaluation of the equivalent notch root radius of the surface profile——the arch-height & chord-length formula. • No single direct index of surface profile can determine the fatigue strength, but the indirect indexes, the notch bottom radius and the stress concentration factor can be used. • The surface notch roots radius ρ is the key to the stress concentration coefficient. Using the arch-height & chord-length formula, the linear fitting goodness of the stress concentration coefficient and the fatigue strength reaches 0.9. Considering the current controversy about the key indicators of surface roughness, this paper presents an indirect evaluation of the equivalent notch root radius of the surface profile. Using this method, the influence of surface roughness on fatigue strength on GH4169 is studied. Various sets of specimens with different fabrication conditions are machined to get a wide range of surface roughness. Vacuum annealing treatment is conducted on some of the specimens to eliminate the effect of residual stresses. Different classical formulae for stress concentration factor based on the notch root radius of the surface profile are used and the fatigue life reduction factor for various surface roughness values is presented. The results show that no single direct index of surface profile can determine the fatigue strength, but the indirect indexes, the notch bottom radius and the stress concentration factor can be used. The surface notch roots radius ρ is the key to the stress concentration coefficient. Using the arch-height & chord - length formula proposed in this paper to evaluate ρ , the linear fitting goodness of the stress concentration coefficient and the fatigue strength reaches 0.9. [ABSTRACT FROM AUTHOR]

• A statistical sampling method was proposed for mass-produced blades measurement. • The statistics confidence region estimation is used to get the minimum sample size. • The correlation analysis is used to determinate the sampling distribution. • The proposed method can reduce the CMM measurement workload significantly. The complex geometry and inevitable manufacturing errors of aero-engine blade profile bring difficulties to high-efficiency and high-accuracy measurement. Usually, blade profile is measured by coordinate measuring machine (CMM) in mass production. Since the measurement time and cost increase proportionally as the increase of sampling points, it is essential to study a sampling method that can answer two basically different sampling problems: how many blades need to be sampled from mass production, and how many points need to be measured for a blade. This paper calculates the sample size for statistical analysis with sufficient confidence and accuracy. The correlation analysis for profile deviations of cross sections (e.g. rotation parameters) and cross-sectional points (e.g. point to point normal distances) is conducted, and the proposed method is carried out through traversing the neighboring Spearman rank correlation coefficient and noting low correlations between each other. The studied cases of two real blades indicated that the proposed statistical sampling method can improve measurement efficiency and ensure the measurement accuracy of mass-produced blades. [ABSTRACT FROM AUTHOR]

A six-axis machining configuration is proposed to improve the surface quality and finishing efficiency of an aeroengine blisk. It flexibly enlarges the accessible interference-free space of the tool for finishing the full-shape surface, including the blade body, root, and hub surfaces. An error model for tool contact posture with respect to the kinematic axis errors is established, revealing the relationship between the kinematic deviation of the axes and resultant profile error. An improved Sobol method is applied for error sensitivity analysis to identify crucial error terms based on the quasi-Monte Carlo algorithm. In particular, an efficient error sensitivity index is proposed by combining a unified objective function to identify crucial error terms, followed by the simulations and cutting experiments for validation. As a result, the blade profile error was successfully suppressed by approximately 40 % in most. This work provides a fundamental framework for elevating the multi-axis machining accuracy of aeroengine blisk. • A six-axis machine tool has been proposed to achieve the full-shape-surface grinding on the blisk. • A constrained error sensitivity index model was proposed to compensate for key error terms. • Sensitivity analysis was conducted using an improved Sobol method incorporated quasi-Monte-Carlo algorithm. • The effectiveness of error sensitivity analysis and corresponding tool-path-based compensation were verified. [ABSTRACT FROM AUTHOR]

Cold atmospheric plasma (CAP) is a unique form of physical plasma that has shown great potential for cancer therapy. CAP uses ionized gas to induce lethal oxidative stress on cancer cells; however, the efficacy of CAP therapy continues to be improved. Here, we report an injectable hydrogel-mediated approach to enhance the anti-tumor efficacy of CAP by regulating the phosphorylation of eIF2α. We discovered that reactive oxygen and nitrogen species (ROS/RNS), two main anti-tumor components in CAP, can lead to lethal oxidative stress on tumor cells. Elevated oxidative stress subsequently induces eIF2α phosphorylation, a pathognomonic marker of immunogenic cell death (ICD). Trehalose, a natural disaccharide sugar, can further enhance CAP-induced ICD by elevating the phosphorylation of eIF2α. Moreover, injectable hydrogel-mediated delivery of CAP/trehalose treatment promoted dendritic cell (DC) maturation, initiating tumor-specific T-cell mediated anti-tumor immune responses. The combination therapy also supported the polarization of tumor-associated macrophages to an M1-like phenotype, reversing the immunosuppressive tumor microenvironment and promoting tumor antigen presentation to T cells. In combination with immune checkpoint inhibitors (i.e., anti-programmed cell death protein 1 antibody, aPD1), CAP/trehalose therapy further inhibited tumor growth. Importantly, our findings also indicated that this hydrogel-mediated local combination therapy engaged the host systemic innate and adaptive immune systems to impair the growth of distant tumors. [ABSTRACT FROM AUTHOR]

• The model of an actuator bonded to a homogeneous half plane with an arbitrarily varying graded coating is analyzed. • The model functions effectively to explore the interfacial behavior of a graded coating with various graded laws. • The interfacial response can be tuned by the inhomogeneity parameter, the variation law and the adhesive interlayer. In the present paper, the model of a piezoelectric actuator bonded to an inhomogeneous substrate, which is composed of a homogeneous half plane and an arbitrarily varying graded coating, is established. Based on the fundamental solution of the inhomogeneous substrate, the governing integro-differential equation of the model is investigated and numerically solved. The interfacial shear stress and the transverse stress in the actuator are comprehensively analyzed. It is found that the interfacial response of the actuator/substrate system can be modified by tuning inhomogeneity parameter and variation law of the graded coating, material and geometric parameters of the adhesive interlayer, etc. A graded coating abiding by an exponential law corresponds to a more reliable interface and a more durable actuator, compared with a linear one. The results should be very helpful to design various film/substrate structures and choose proper graded coating in real applications. [ABSTRACT FROM AUTHOR]

Highlights • A new frictional contact model of an arbitrarily oriented substrate loaded by a rigid flat indenter is investigated in the paper, in which a spatially varying friction coefficient is included. • The proposed model functions effectively to explore the contact stress field as well as stress singularity near contact ends. • The contact behavior is significantly influenced by the friction coefficient, inhomogeneity parameter as well as gradient orientation angle of the graded substrate. Abstract A new frictional contact model of an arbitrarily oriented substrate loaded by a rigid flat indenter is proposed in the present paper, in which a spatially varying friction coefficient is considered. With the aid of Fourier integral transformation, the governing equation is obtained and solved semi-analytically. The surface contact stress field, the moment applied to make the indenter move vertically to the substrate's top surface, as well as the nominal friction coefficient are investigated comprehensively. It is found that the contact behavior can be well improved by choosing proper friction coefficient, inhomogeneity parameter as well as gradient orientation angle. The new finding of the present paper should be helpful to access the surface wear resistance and design various inhomogeneous composites. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]

Abstract Cold atmospheric plasma (CAP) is an emerging biomedical technique that shows great potential for cancer treatment. On the other hand, magnetic nanoparticles open up a wide field of possible applications in medicine. Here we seek to develop a novel dual cancer therapeutic method by integrating promising CAP and iron oxide-based magnetic nanoparticles (MNPs), and evaluate its underlying mechanism for targeted lung cancer treatment. For this purpose, the synergistic effects of CAP and iron oxide-based MNPs on cellular bioactivity, epidermal growth factor receptor (EGFR) expression, and EGFR downstream signaling pathways were investigated. Results showed that the effectiveness of CAP and iron oxide-based MNPs for synergistic strongly killed activity against lung cancer cells, and significantly inhibited cell proliferation via reduction of viability and induction of apoptosis. Importantly, CAP combining with iron oxide-based MNPs induced EGFR downregulation while CAP inhibited lung cancer cells via depressing pERK and pAKT. Translation of these findings to an in vivo setting demonstrates that CAP combining iron oxide-based MNPs is effective at preventing xenograft tumors. Thus, the integration of CAP and iron oxide-based MNPs provides a promising tool for the development of a new cancer treatment strategy. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

Despite the promise of immune checkpoint blockade (ICB) for cancer treatment, challenges associated with this therapy still exist, including low response rates and severe side effects in patients. Here, we report a hydrogel-mediated combination therapy for enhanced ICB therapy. Specifically, cold atmospheric plasma (CAP), an ionized gas consisting of therapeutically effective reactive oxygen species (ROS) and reactive nitrogen species (RNS), can effectively induce cancer immunogenic cell death, releasing tumor-associated antigens in situ and initiating anti-tumor immune responses, which, therefore, can synergistically augment the efficacy of immune checkpoint inhibitors. To minimize the systemic toxicity of immune checkpoint inhibitors and improve the tissue penetration of CAP, an injectable Pluronic hydrogel was employed as a delivery method. Our results show that major long-lived ROS and RNS in CAP can be effectively persevered in Pluronic hydrogel and remain efficacious in inducing cancer immunogenic cell death after intratumoral injection. Our findings suggest that local hydrogel-mediated combination of CAP and ICB treatment can evoke both strong innate and adaptive, local and systemic anti-tumor immune responses, thereby inhibiting both tumor growth and potential metastatic spread. [ABSTRACT FROM AUTHOR]

The improvement of the ignition and combustion performance of aerospace engines under extreme conditions such as high altitude, low temperature, low pressure, and high speed is a research topic of broad and current interest. Plasma technology has attracted increasing attention due to its significant potential in improving ignition and combustion performance. Scientists and engineers have conducted numerous investigations and experiments on the use of plasma technology in aerospace engines, especially in aviation gas turbine engines, driving the research and applications of plasma-assisted ignition (PAI) and plasma-assisted combustion (PAC). The aim of this comprehensive review paper is to summarize and discuss the developments and applications of PAI and PAC in the fields of aerospace engines during the last ten years, including ignition, lean blow-out, combustion efficiency, emission, outlet temperature distribution quality, combustion stability, and fuel distribution. This review paper mainly focuses on experimental research progress. We also introduce new applications of PAI and PAC in novel aerospace engines and discuss the prospects for its practical implementation. [ABSTRACT FROM AUTHOR]