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Applications of flexible polyimide: barrier material, sensor material, and functional material
No full textPolyimide (PI), as an advanced polymer material, possesses the intrinsic merits of excellent resistance to extreme temperatures, good dielectric properties, flame resistance, strong processibility, biocompatibility, and flexibility. The outstanding performances of flexible PI have led to a wide range of applications in aerospace, medical, intelligent electronic devices, energy storage devices, and more. Notably, due to the swift progress of various flexible and soft devices, flexible PI has become ubiquitous in the form of thin films, fibers, and foam and gradually plays an indispensable role in all sorts of those devices. This review mainly focuses on the current advances in the usage of flexible PI for barrier, sensor, and functional purposes. Firstly, the key features of various methods for synthesizing and processing PI, as well as the relationship with their respective applications, are summarized. Secondly, to give readers a comprehensive view of the various applications of flexible PI materials, the applications are broken down into three categories: flexible barrier applications, flexible sensing applications, and flexible function applications, and the current research of each application is introduced in detail. Finally, a summary of the challenges and possible solutions in some flexible applications is present
Robotic-assisted microsurgery for lymphedema treatment
No full textThe recent development of robotic-assisted microsurgery and supermicrosurgery has raised great expectations to support some of the most demanding microsurgical procedures, which are applied in lymphatic reconstructive surgery to restore lymphatic vascular integrity and treat lymphedema. Procedures such as the establishment of lymphovenous anastomosis (LVA), the harvest of lymph nodes from anatomic locations that reduce donor-side morbidity and the transplantation of the vascularized lymph node flaps (VLNT) present procedures necessitating extreme precision and dexterity in often difficult-to-reach areas, thus pushing the physical limitations of the performing microsurgeon. Despite being limited in number, recent preclinical and clinical studies of independent groups using different robotic systems demonstrate the feasibility of robotic technology to perform supermicrosurgical procedures successfully. The robotic assistance offers unparalleled precision, refining the surgical techniques and minimizing potential side effects, with clinical outcomes comparable to the conventional techniques. Although the relative disadvantages of robotic assistance mostly appear to be related to adequate training and the prolonged learning curve, the technology promises to revolutionize the field of supermicrosurgery and improve the clinical outcomes of lymphatic reconstructive surgery
Recent progress on alloy-based anode materials for potassium-ion batteries
No full textPotassium-ion batteries (PIBs) are considered as promising alternatives to lithium-ion batteries due to the abundant potassium resources in the Earth’s crust. Establishing high-performance anode materials for PIBs is essential to the development of PIBs. Recently, significant research effort has been devoted to developing novel anode materials for PIBs. Alloy-based anode materials that undergo alloying reactions and feature combined conversion and alloying reactions are attractive candidates due to their high theoretical capacities. In this review, the current understanding of the mechanisms of alloy-based anode materials for PIBs is presented. The modification strategies and recent research progress of alloy-based anodes and their composites for potassium storage are summarized and discussed. The corresponding challenges and future perspectives of these materials are also proposed
Perspective: microbial interventions in the urinary tract
No full textDespite multiple advances in medicine, the management of urinary tract infections (UTIs) in women has remained stalled for decades. To prevent the development of symptomatic recurrences, low-dose antibiotics are the mainstay, while alternative approaches have been attempted with limited success. The use of probiotics was first considered forty years ago, and while some promising studies have been published, additional evidence in larger patient groups is needed to recommend specific strains as a primary preventive regimen. Overall, the role of beneficial microbes in reducing the risk of UTI and other urological diseases, such as urolithiasis, remains a target for researchers. The aim of this perspective is to offer a viewpoint on the status of this approach and recommendations for how to develop novel probiotic therapies
Occurrence and distribution of several endocrine-disrupting chemicals in a chemical park: exploring the health risks of multiple pollutants
No full textTriclosan (TCS), triclocarban (TCC), parabens, bisphenols (BPAs), tetrabromobisphenol A and its alternatives (TBBPAs), and phthalate esters (PAEs) are typical endocrine-disrupting chemicals (EDCs), which have received increasing attention due to their potential adverse effects on ecological and human health. Human exposure to these EDCs is widespread. However, data regarding the distribution and related health risks of multiple EDCs in chemical parks are relatively scarce. In this study, 28 EDCs were determined in surface soil, sediment, and sludge samples collected from the Yangkou Chemical Industrial Park (Jiangsu, China). With the exception of TBBPAs, the distributions of Σ(TCS + TCC), Σ6parabens, Σ8BPAs, and Σ9PAEs in environmental media were as follows: sludge > sediment ≥ soil. No obvious differences were found regarding the concentrations of Σ9PAEs within the soil samples. Higher levels of Σ(TCS + TCC) (186 μg kg-1 dw) and Σ3TBBPAs (154 μg kg-1 dw) were found in the soil near a chemical manufacturer and the main sewage outlet of a wastewater treatment plant, respectively. The non-carcinogenic risks of EDCs from soil were estimated, and the risk levels were found to be a few orders of magnitude lower than the reported reference dose (RfD) values. The hazard indexes for all the samples were smaller than one, suggesting that the chemical industrial park posed a low risk to the workers. Additionally, the mass inventories of Σ(TCS + TCC), Σ6parabens, Σ8BPAs, Σ3TBBPAs, and Σ9PAEs were estimated to be 507, 90.6, 133, 20.7, and 1090 kg, respectively. These findings help to establish baseline concentrations for EDCs in soil, sediment, and sludge in a chemical industrial park
Agroforestry systems for mitigating climate change and reducing Carbon Footprints of land-use systems in Southern Africa
No full textFarming systems in Southern Africa are mostly maize mixed cropping, with some tree and/or root crop-based systems. Agroforestry systems (AFS), in particular, represent a model for ecological sustainability, with the potential of sequestering carbon (C) within soils and biomass. This review reveals that rotational woodlots sequester more C than other AFS types in the region. Additionally, C levels above and below ground range from 0.29 to 15.21 Mg ha-1 yr-1 and 30 to 300 Mg C ha-1 in the first 100 cm soil depth, respectively. To measure C below- and aboveground biomass in different AFS, variable - and not easily adoptable - methodologies are being used in Southern Africa, which limits the standardization of C stock accounting. Since the magnitude of C sequestered in AFS is dependent on the species used, AF and farm management, and environmental conditions, we recommend the adoption of rigorous and replicable methodologies to account for C stocks in different AFS over time in Southern Africa
Recent progress in strategies for preparation of metal-organic frameworks and their hybrids with different dimensions
No full textAs a new kind of organic-inorganic hybrid porous material, metal-organic frameworks (MOFs) exhibit a wide application prospect in gas storage and separation, catalysis and sensing due to their characteristics of large specific surface area, high porosity and coordination unsaturation. As more and more types of MOFs were reported, the synthetic strategies of MOFs-based materials have become a hot research topic. According to the morphological dimension, MOFs can be roughly divided into one-dimensional, two-dimensional and three-dimensional structures. Herein, we summarize the synthetic methods and principles of MOFs from multi-dimensional perspectives, and explore the growth mechanism of MOFs with different morphologies based on dynamic and thermodynamic tuning. Finally, based on the above summaries, the challenges and opportunities of MOFs in the future are discussed
An ultraviolet-visible distinguishable broadband photodetector based on the positive and negative photoconductance effects of a graphene/ZnO quantum dot heterostructure
No full textBroadband photodetectors covering the ultraviolet (UV) to visible range are significant for applications in communication and imaging. Broadband photodetectors with the capacity to distinguish wavelength bands are highly desirable because they can provide additional spectral information. Herein, we report a UV-visible distinguishable broadband photodetector based on a graphene/ZnO quantum dot heterostructure. The photodetector exhibits negative photoconductance under visible illumination because the adsorbents on graphene act as scattering centers to reduce the carrier mobility. In contrast, under UV illumination, the photodetector shows positive photoconductance as the photogenerated electrons in the ZnO quantum dots transfer to the graphene, thereby increasing the conductivity. Thus, the detection and distinction of UV and visible illumination can be realized by utilizing the opposing photoconductivity changes. These results offer inspiration for the design of multifunctional broadband photodetectors
BaTiO3-NaNbO3 energy storage ceramics with an ultrafast charge-discharge rate and temperature-stable power density
No full textDielectric capacitors with ultrafast charge-discharge rates are extensively used in electrical and electronic systems. To meet the growing demand for energy storage applications, researchers have devoted significant attention to dielectric ceramics with excellent energy storage properties. As a result, the awareness of the importance of the pulsed discharge behavior of dielectric ceramics and conducting characterization studies has been raised. However, the temperature stability of pulsed discharge behavior, which is significant for pulsed power applications, is still not given the necessary consideration. Here, we systematically investigate the microstructures, energy storage properties and discharge behaviors of nanograined (1-x)BaTiO3-xNaNbO3 ceramics prepared by a two-step sintering method. The 0.60BaTiO3-0.40NaNbO3 ceramics with relaxor ferroelectric characteristics possess an optimal discharge energy density of 3.07 J cm-3, a high energy efficiency of 92.6%, an ultrafast discharge rate of 39 ns and a high power density of 100 MW cm-3. In addition to stable energy storage properties in terms of frequency, fatigue and temperature, the 0.60BaTiO3-0.40NaNbO3 ceramics exhibit temperature-stable power density, thereby illustrating their significant potential for power electronics and pulsed power applications
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