Exceptional power conversion efficiency (PCE) of 25.7% in perovskite solar cells (PSCs) has been achieved, which is comparable with their traditional rivals (Si‐based solar cells). However, ...commercialization‐worthy efficiency and long‐term stability remain a challenge. In this regard, there are increasing studies focusing on the interface engineering in PSC devices to overcome their poor technical readiness. Herein, the roles of electrode materials and interfaces in PSCs are discussed in terms of their PCEs and perovskite stability. All the current knowledge on the factors responsible for the rapid intrinsic and external degradation of PSCs is presented. Then, the roles of carbonaceous materials as substitutes for noble metals are focused on, along with the recent research progress in carbon‐based PSCs. Furthermore, a sub‐category of PSCs, that is, flexible PSCs, is considered as a type of exceptional power source due to their high power‐to‐weight ratios and figures of merit for next‐generation wearable electronics. Last, the future perspectives and directions for research in PSCs are discussed, with an emphasis on their commercialization.
The roles of electrode materials and interfaces in perovskite solar cell (PSC) devices are discussed in terms of perovskite stability. The various factors responsible for rapid degradation in PSCs are provided. Then, the roles of carbonaceous materials for carbon‐based PSC as a substitute for noble metals are addressed, along with the recent progress.
Induced pluripotent stem cell (iPSC)-derived mesenchymal stem cells (iMSCs) serve as a unique source for cell therapy. We investigated whether exosomes from iMSCs promote the proliferation of human ...keratinocytes (HaCaT) and human dermal fibroblasts (HDFs). iPSCs were established from human Wharton's jelly MSCs and were allowed to differentiate into iMSCs. Exosomes were collected from the culture supernatant of MSCs (MSC-exo) and iMSCs (iMSC-exo), and their characteristics were investigated. Both exosome types possessed basic characteristics of exosomes and were taken up by skin cells in vitro and in vivo. A significant increase in HaCaT proliferation was observed with iMSC-exo, although both exosomes increased the viability and cell cycle progression in HaCaT and HDFs. No significant difference was observed in the closure of wound scratch and the expression of reparative genes between cells treated with the two exosome types. Both exosomes enhanced the secretion of collagen in HaCaT and HDFs; however, an increase in fibronectin level was observed only in HaCaT, and this effect was better with iMSC-exo treatment. Only iMSC-exo increased the phosphorylation of extracellular signal-regulated kinase (ERK)-1/2. Our results indicate that iMSC-exo promote the proliferation of skin cells by stimulating ERK1/2 and highlight the application of iMSCs for producing exosomes.
With COVID-19 widespread worldwide, people are still struggling to develop faster and more accurate diagnostic methods. Here we demonstrated the label-free detection of SARS-CoV-2 spike protein by ...employing a SARS-CoV-2 spike antibody-conjugated phase-shifted long-period fiber grating (PS-LPFG) inscribed with a CO2 laser. At a specific cladding mode, the wavelength separation (λD) between the two split dips of a PS-LPFG varies with the external refractive index, although it is virtually insensitive to ambient temperature variations. To detect SARS-CoV-2 spike protein, SARS-CoV-2 spike antibodies were immobilized on the fiber surface of the fabricated PS-LPFG functionalized through chemical modification. When exposed to SARS-CoV-2 spike protein with different concentrations, the antibody-immobilized PS-LPFG exhibited the variation of λD according to the protein concentration, which was caused by bioaffinity binding-induced local changes in the refractive index at its surface. In particular, we also confirmed the potential of our sensor for clinical application by detecting SARS-CoV-2 spike protein in virus transport medium. Moreover, our sensor could distinguish SARS-CoV-2 spike protein from those of MERS-CoV and offer efficient properties such as reusability and storage stability. Hence, we have successfully fabricated a promising optical transducer for the detection of SARS-CoV-2 spike protein, which can be unperturbed by external temperature disturbances.
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•This is the first report on detecting SARS-CoV-2 with a long-period fiber grating.•A grating surface was functionalized and conjugated with SARS-CoV-2 spike antibody.•Antigen protein could be detected in standard buffer and clinical transport medium.•Our biosensor also provided efficient reusability and reasonable storage stability.
Very recently, MXene‐based wearable hydrogels have emerged as promising candidates for epidermal sensors due to their tissue‐like softness and unique electrical and mechanical properties. However, it ...remains a challenge to achieve MXene‐based hydrogels with reliable sensing performance and prolonged service life, because MXene inevitably oxidizes in water‐containing system of the hydrogels. Herein, catechol‐functionalized poly(vinyl alcohol) (PVA‐CA)‐based hydrogels is proposed to inhibit the oxidation of MXene, leading to rapid self‐healing and superior strain sensing behaviors. Sufficient interaction of hydrophobic catechol groups with the MXene surface reduces the oxidation‐accessible sites in the MXene for reaction with water and eventually suppresses the oxidation of MXene in the hydrogel. Furthermore, the PVA‐CA‐MXene hydrogel is demonstrated for use as a strain sensor for real‐time motion monitoring, such as detecting subtle human motions and handwriting. The signals of PVA‐CA‐MXene hydrogel sensor can be accurately classified using deep learning models.
This study provides an avenue for the synthesis of oxidation‐resistant MXene‐based catechol‐grafted poly (vinyl alcohol) hydrogels (PVA‐CA‐MXene hydrogel) with prolonged service life intended for strain sensors in real‐time motion monitoring, such as detecting subtle human motions and handwriting. The signals of PVA‐CA‐MXene hydrogel sensor are further accurately classified using deep learning models.
Stealth technology is used to enhance the survival of military equipment in the field of military surveillance, as it utilizes a combination of techniques to render itself undetectable by enemy radar ...systems. Radar absorbing materials (RAMs) are specialized materials used to reduce the reflection (or absorption) of radar signals to provide stealth capability, which is a core component of passive countermeasures in military applications. The properties of RAMs can be optimized by adjusting their composition, microstructure, and surface geometry. Carbon-based materials present a promising approach for the fabrication of ultrathin, versatile, and high-performance RAMs due to their large specific surface area, lightweight, excellent dielectric properties, high electrical conductivity, and stability under harsh conditions. This review begins with a brief history of stealth technology and an introduction to electromagnetic waves, radar systems, and radar absorbing materials. This is followed by a discussion of recent research progress in carbon-based RAMs, including carbon blacks, carbon fibers, carbon nanotubes, graphite, graphene, and MXene, along with an in-depth examination of the principles and strategies on electromagnetic attenuation characteristics. Hope this review will offer fresh perspectives on the design and fabrication of carbon-based RAMs, thereby fostering a deeper fundamental understanding and promoting practical applications.
Various applications of TiO2 photocatalysis in environment and energy fields.
Recently, many water treatment technologies, such as biological treatment, coagulation/precipitation techniques, Fenton ...oxidation treatments, and advanced oxidation techniques, have been assessed to address the worsening clean water shortage. This review summarizes these technologies and provides the background and principle of photocatalysis for advanced oxidation technology. In particular, this paper focuses on semiconductor TiO2 photocatalysts as well as the latest modifications of TiO2 photocatalyst, such as the introduction of metals or heteroatoms onto TiO2, physical modification of TiO2 for a variety of morphologies, and hybrid TiO2/nanocarbon composites, to improve the photocataytic activities for an advanced oxidation process. This review provides useful information to scientists and engineers in this field.
Melanopsin is expressed in distinct types of intrinsically photosensitive retinal ganglion cells (ipRGCs), which drive behaviors from circadian photoentrainment to contrast detection. A major ...unanswered question is how the same photopigment, melanopsin, influences such vastly different functions. Here we show that melanopsin’s role in contrast detection begins in the retina, via direct effects on M4 ipRGC (ON alpha RGC) signaling. This influence persists across an unexpectedly wide range of environmental light levels ranging from starlight to sunlight, which considerably expands the functional reach of melanopsin on visual processing. Moreover, melanopsin increases the excitability of M4 ipRGCs via closure of potassium leak channels, a previously unidentified target of the melanopsin phototransduction cascade. Strikingly, this mechanism is selective for image-forming circuits, as M1 ipRGCs (involved in non-image forming behaviors), exhibit a melanopsin-mediated decrease in excitability. Thus, melanopsin signaling is repurposed by ipRGC subtypes to shape distinct visual behaviors.
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•Melanopsin enhances contrast sensitivity of M4 ipRGCs (ON alpha cells)•Melanopsin phototransduction increases M4 ipRGC intrinsic excitability•Melanopsin phototransduction closes leak potassium channels in M4 ipRGCs•Melanopsin modulates M4 ipRGC physiology across a wide range of light intensities
Sonoda et al. identify leak potassium channels as the major target of melanopsin phototransduction in M4 ipRGCs/ON alpha retinal ganglion cells. Melanopsin-dependent closure of these channels enhances cell excitability and contrast sensitivity across a wide range of light intensities.
Care can itself be a form of violence that masks hierarchical control and violates ethical singularity. Drawing on feminist philosophies of care, I argue that structural modes of violence are ...embedded in pervasive care ethics. Han Kang's novel The Vegetarian (2007) demonstrates two contradictory responses to care ethics. The protagonist Yeong-hye leans into her moral values through radical vegetarianism, believing that her eating practices free her from acts of violence not only toward humans but also toward animals. Her ethical decision, however, creates family conflicts, as her moral stand is considered an ethical evasion of wifely and daughterly care obligations. Han Kang's novel indicates that maternal figures can also inadvertently support hierarchical culture and patriarchal norms embedded in daily caring practices. Her family's care imperative attempts to normalize Yeong-hye's diet and thus violates her ethics. My reading of The Vegetarian not only informs my theory of gendered care - considering the normative reflection of social expectation in care relations - but also proffers an intervention in the subtle forms of naturalized care violence in the postcolonial South Korean imaginary of a convivial future.
Mesenchymal stromal/stem cells (MSCs) have been developed as a promising source for cell‐based therapies of ischemic disease. However, there are some hurdles in their clinical application such as ...poor cell engraftment and inconsistent stem cell potency. In this study, we sought to find biomarkers for predicting potency of MSCs for proangiogenic therapy to improve their beneficial effects. Large variations were observed in proangiogenic factor secretion profiles of conditioned media derived from nine different donor‐derived Wharton's jelly (WJ)‐derived MSCs and 8 factors among 55 angiogenesis‐related factors were secreted at considerable levels. Two distinct WJ‐MSCs that had the lowest or the highest secretion of these eight factors showed corresponding proangiogenic activities in in vitro angiogenesis assays. When four additional different donor‐derived WJ‐MSCs were further examined, proangiogenic activities in migration and tube formation of endothelial cells and in in vivo Matrigel plug assay were highly consistent with secretion levels of four major factors (angiogenin, interleukin‐8, monocyte chemoattractant protein‐1, and vascular endothelial growth factor). Such correlation was also observed in vascular regenerative effect in a mouse hind limb ischemia model. Blocking of these four factors by neutralizing antibodies or knockdown of them by siRNA treatment resulted in significant inhibition of proangiogenic activities of not only WJ‐MSCs, but also bone marrow‐derived MSCs. These results suggest that these four factors may represent efficient biomarkers for predicting vascular regenerative efficacy of MSCs. Stem Cells 2019;37:77–88
Heterogeneity in the secretome profiles of mesenchymal stromal/stem cells (MSCs) derived from different donors or tissues results in inconsistent stem cell potency. A minimal set of proangiogenic factors consisting of angiogenin, IL‐8, MCP‐1, and vascular endothelial growth factor that are selected from this study is proposed as efficient biomarkers for predicting vascular regenerative efficacy in the treatment of ischemic disease. These biomarkers will be helpful for manufacturing stem cells that are reproducibly effective in the clinic.
The label-free detection of SARS-CoV-2 spike protein is demonstrated by using slightly tapered no-core fiber (ST-NCF) functionalized with ACE2. In the fabricated sensor head, abrupt changes in the ...mode-field diameter at the interfaces between single-mode fiber and no-core fiber excite multi-guided modes and facilitate multi-mode interference (MMI). Its slightly tapered region causes the MMI to be more sensitive to the refractive index (RI) modulation of the surrounding medium. The transmission minimum of the MMI spectrum was selected as a sensor indicator. The sensor surface was functionalized with ACE2 bioreceptors through the pretreatment process. The ACE2-immobilized ST-NCF sensor head was exposed to the samples of SARS-CoV-2 spike protein with concentrations ranging from 1 to 10
4
ng/mL. With increasing sample concentration, we observed that the indicator dip moved towards a longer wavelength region. The observed spectral shifts are attributed to localized RI modulations at the sensor surface, which are induced by selective bioaffinity binding between ACE2 and SARS-CoV-2 spike protein. Also, we confirmed the capability of the sensor head as an effective and simple optical probe for detecting antigen protein samples by applying saliva solution used as a measurement buffer. Moreover, we compared its detection sensitivity to SARS-CoV-2 and MERS-CoV spike protein to examine its cross-reactivity. In particular, we proved the reproducibility of the bioassay protocol adopted here by employing the ST-NCF sensor head reconstructed with ACE2. Our ST-NCF transducer is expected to be beneficially utilized as a low-cost and portable biosensing platform for the rapid detection of SARS-CoV-2 spike protein.
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