Reports that promote persulfate-based advanced oxidation process (AOP) as a viable alternative to hydrogen peroxide-based processes have been rapidly accumulating in recent water treatment ...literature. Various strategies to activate peroxide bonds in persulfate precursors have been proposed and the capacity to degrade a wide range of organic pollutants has been demonstrated. Compared to traditional AOPs in which hydroxyl radical serves as the main oxidant, persulfate-based AOPs have been claimed to involve different in situ generated oxidants such as sulfate radical and singlet oxygen as well as nonradical oxidation pathways. However, there exist controversial observations and interpretations around some of these claims, challenging robust scientific progress of this technology toward practical use. This Critical Review comparatively examines the activation mechanisms of peroxymonosulfate and peroxydisulfate and the formation pathways of oxidizing species. Properties of the main oxidizing species are scrutinized and the role of singlet oxygen is debated. In addition, the impacts of water parameters and constituents such as pH, background organic matter, halide, phosphate, and carbonate on persulfate-driven chemistry are discussed. The opportunity for niche applications is also presented, emphasizing the need for parallel efforts to remove currently prevalent knowledge roadblocks.
Centralized water treatment has dominated in developed urban areas over the past century, although increasing challenges with this model demand a shift to a more decentralized approach wherein ...advanced oxidation processes (AOPs) can be appealing treatment options. Efforts to overcome the fundamental obstacles that have thus far limited the practical use of traditional AOPs, such as reducing their chemical and energy input demands, target the utilization of heterogeneous catalysts. Specifically, recent advances in nanotechnology have stimulated extensive research investigating engineered nanomaterial (ENM) applications to AOPs. In this Perspective, we critically evaluate previously studied ENM catalysts and the next-generation treatment technologies they seek to enable. Opportunities for improvement exist at the intersection of materials science and treatment process engineering, as future research should aim to enhance catalyst properties while considering the unique roadblocks to practical ENM implementation in water treatment.
We herein report the first instance of aqueous-phase photosensitization of semiconductor photocatalysts (WO3 loaded with Pt) through triplet–triplet annihilation (TTA)-based upconversion of ...sub-band-gap photons. The TTA-based upconversion (UC) was achieved in the aqueous phase by encapsulating the solvent phase containing a benchmark platinum(II) octaethylporphyrin/9,10-diphenylanthracene sensitizer/acceptor pair in a rigid polymer shell in the form of aqueous dispersible microcapsules. A mixture of hexadecane and polyisobutylene was used as the inner solvent phase. This eliminated the need for the deoxygenation step that is essential for existing TTA-based UC processes and enabled stable UC to occur even after a month of exposure to the ambient environment. The photoluminescence properties were examined, and UC-assisted photochemical production of hydroxyl radical from green (532 nm) light irradiation was demonstrated for the first time.
Microglia-astrocyte crosstalk has recently been at the forefront of glial research. Emerging evidence illustrates that microglia- and astrocyte-derived signals are the functional determinants for the ...fates of astrocytes and microglia, respectively. By releasing diverse signaling molecules, both microglia and astrocytes establish autocrine feedback and their bidirectional conversation for a tight reciprocal modulation during central nervous system (CNS) insult or injury. Microglia, the constant sensors of changes in the CNS microenvironment and restorers of tissue homeostasis, not only serve as the primary immune cells of the CNS but also regulate the innate immune functions of astrocytes. Similarly, microglia determine the functions of reactive astrocytes, ranging from neuroprotective to neurotoxic. Conversely, astrocytes through their secreted molecules regulate microglial phenotypes and functions ranging from motility to phagocytosis. Altogether, the microglia-astrocyte crosstalk is fundamental to neuronal functions and dysfunctions. This review discusses the current understanding of the intimate molecular conversation between microglia and astrocytes and outlines its potential implications in CNS health and disease.
Printing technology can be used for manufacturing stretchable electrodes, which represent essential parts of wearable devices requiring relatively high degrees of stretchability and conductivity. In ...this work, a strategy for fabricating printable and highly stretchable conductors are proposed by transferring printed Ag ink onto stretchable substrates comprising Ecoflex elastomer and tough hydrogel layers using a water‐soluble tape. The elastic modulus of the produced hybrid film is close to that of the hydrogel layer, since the thickness of Ecoflex elastomer film coated on hydrogel is very thin (30 µm). Moreover, the fabricated conductor on hybrid film is stretched up to 1780% strain. The described transfer method is simpler than other techniques utilizing elastomer stamps or sacrificial layers and enables application of printable electronics to the substrates with low elastic moduli (such as hydrogels). The integration of printed electronics with skin‐like low‐modulus substrates can be applied to make wearable devices more comfortable for human skin.
Printable and highly stretchable conductors are realized by transferring printed Ag ink onto stretchable substrates comprising Ecoflex and tough hydrogel layers. The elastic modulus of the produced hybrid film is close to that of the hydrogel layer, since the thickness of Ecoflex coated on hydrogel is very small. The fabricated conductor on hybrid film is stretched up to 1780% strain.
Abstract
Single atom catalysts have been found to exhibit superior selectivity over nanoparticulate catalysts for catalytic reactions such as hydrogenation due to their single-site nature. However, ...improved selectively is often accompanied by loss of activity and slow kinetics. Here we demonstrate that neighboring Pd single atom catalysts retain the high selectivity merit of sparsely isolated single atom catalysts, while the cooperative interactions between neighboring atoms greatly enhance the activity for hydrogenation of carbon-halogen bonds. Experimental results and computational calculations suggest that neighboring Pd atoms work in synergy to lower the energy of key meta-stable reactions steps, i.e., initial water desorption and final hydrogenated product desorption. The placement of neighboring Pd atoms also contribute to nearly exclusive hydrogenation of carbon-chlorine bond without altering any other bonds in organohalogens. The promising hydrogenation performance achieved by neighboring single atoms sheds light on a new approach for manipulating the activity and selectivity of single atom catalysts that are increasingly studied in multiple applications.
Nanoscale catalysts that can enable Fenton-like chemistry and produce reactive radicals from hydrogen peroxide activation have been extensively studied in order to overcome the limitations of ...homogeneous Fenton processes. Despite several advantageous features, limitation in mass transfer of short-lived radical species is an inherent drawback of the heterogeneous system. Here, we present a mechanistic foundation for the way spatial confinement of Fenton chemistry at the nanoscale can significantly enhance the kinetics of radical-mediated oxidation reactionspollutant degradation in particular. We synthesized a series of Fe3O4-functionalized nanoreactors with precise pore dimensions, based on an anodized aluminum oxide template, to enable quantitative analysis of nanoconfinement effects. Combined with computational simulation of spatial distribution of radicals, we found that hydroxyl radical concentration was strongly dependent on the distance from the surface of Fenton catalysts. This distance dependency significantly influences the gross reaction kinetics and accounts for the observed nanoconfinement effects. We further found that a length scale below 25 nm is critical to avoid the limitation of short-lived species diffusion and achieve kinetics that are orders of magnitude faster than those obtained in a batch suspension of heterogeneous catalysts. These findings suggest a new strategy to develop an innovative heterogeneous catalytic system with the most effective use of hydroxyl radicals in oxidation treatment scenarios.
Objectives
The aim of the current study was to evaluate the detection and diagnosis of three types of odontogenic cystic lesions (OCLs)—odontogenic keratocysts, dentigerous cysts, and periapical ...cysts—using dental panoramic radiography and cone beam computed tomographic (CBCT) images based on a deep convolutional neural network (CNN).
Methods
The GoogLeNet Inception‐v3 architecture was used to enhance the overall performance of the detection and diagnosis of OCLs based on transfer learning. Diagnostic indices (area under the ROC curve AUC, sensitivity, specificity, and confusion matrix with and without normalization) were calculated and compared between pretrained models using panoramic and CBCT images.
Results
The pretrained model using CBCT images showed good diagnostic performance (AUC = 0.914, sensitivity = 96.1%, specificity = 77.1%), which was significantly greater than that achieved by other models using panoramic images (AUC = 0.847, sensitivity = 88.2%, specificity = 77.0%) (p = .014).
Conclusions
This study demonstrated that panoramic and CBCT image datasets, comprising three types of odontogenic OCLs, are effectively detected and diagnosed based on the deep CNN architecture. In particular, we found that the deep CNN architecture trained with CBCT images achieved higher diagnostic performance than that trained with panoramic images.
A simple heat treatment, perhaps the most globally recognized point-of-use water sterilization method, is seemingly effective against all major pathogens of concern, but bulk water boiling is not ...energy efficient or sustainable. Herein, we present the first application of solar-to-thermal converting nanomaterials for the direct inactivation of bacteria and viruses in drinking water through the application of Au nanorods, carbon black, and Au nanorod-carbon black composite materials as light absorbers. With broad absorption bands spanning the visible and near-infrared wavelengths, at sufficient concentrations, these nanoparticles induce multiple scattering events, increasing photon absorption probability and concentrating the light within a small spatial domain, leading to localized, intense heating that inactivates microorganisms in close proximity. Moving toward practical device design, we have developed a facile silane immobilization approach to fabricate films with densely packed layers of photothermal nanomaterials. Our results suggest that upon irraditaion with simulated solar light, these films can thermally inactivate bacteria and viruses, as demonstrated through the inactivation of surrogate organisms Escherichia coli K-12, and bacteriophages MS2 and PR772.
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