Low-rank representation (LRR) has recently attracted a great deal of attention due to its pleasing efficacy in exploring low-dimensional subspace structures embedded in data. For a given set of ...observed data corrupted with sparse errors, LRR aims at learning a lowest-rank representation of all data jointly. LRR has broad applications in pattern recognition, computer vision and signal processing. In the real world, data often reside on low-dimensional manifolds embedded in a high-dimensional ambient space. However, the LRR method does not take into account the non-linear geometric structures within data, thus the locality and similarity information among data may be missing in the learning process. To improve LRR in this regard, we propose a general Laplacian regularized low-rank representation framework for data representation where a hypergraph Laplacian regularizer can be readily introduced into, i.e., a Non-negative Sparse Hyper-Laplacian regularized LRR model (NSHLRR). By taking advantage of the graph regularizer, our proposed method not only can represent the global low-dimensional structures, but also capture the intrinsic non-linear geometric information in data. The extensive experimental results on image clustering, semi-supervised image classification and dimensionality reduction tasks demonstrate the effectiveness of the proposed method.
Abstract
Metal–organic frameworks (MOFs) are highly versatile materials that have been identified as promising candidates for membrane‐based gas separation applications due to their uniformly narrow ...pore windows and virtually unlimited structural and chemical features. Defect engineering of MOFs has opened new opportunities for manipulating MOF structures, providing a simple yet efficient approach for enhancing membrane separation. However, the utilization of this strategy to tailor membrane microstructures and enhance separation performance is still in its infancy. Thus, this summary aims to provide a guideline for tailoring defective MOF‐based membranes. Recent developments in defect engineering of MOF‐based membranes will be discussed, including the synthesis strategies for defective MOFs, the effects of defects on the gas adsorption properties, gas transport mechanisms, and recently reported defective MOF‐based membranes. Furthermore, the emerging challenges and future prospects will be outlined. Overall, defect engineering offers an exciting opportunity to improve the performance of MOF‐based gas membranes. However, there is still a long way to go to fully understand the influence of defects on MOF properties and optimize the design of MOF‐based membranes for specific gas separation applications. Nonetheless, continued research in this field holds great promise for the development of next‐generation membrane‐based gas separation technologies.
Mitochondria are essential organelles that regulate cellular energy homeostasis and cell death. The removal of damaged mitochondria through autophagy, a process called mitophagy, is thus critical for ...maintaining proper cellular functions. Indeed, mitophagy has been recently proposed to play critical roles in terminal differentiation of red blood cells, paternal mitochondrial degradation, neurodegenerative diseases, and ischemia or drug-induced tissue injury. Removal of damaged mitochondria through autophagy requires two steps: induction of general autophagy and priming of damaged mitochondria for selective autophagic recognition. Recent progress in mitophagy studies reveals that mitochondrial priming is mediated either by the Pink1-Parkin signaling pathway or the mitophagic receptors Nix and Bnip3. In this review, we summarize our current knowledge on the mechanisms of mitophagy. We also discuss the pathophysiological roles of mitophagy and current assays used to monitor mitophagy.
With the spread of the novel coronavirus disease 2019 (COVID-19) around the world, the estimation of the incubation period of COVID-19 has become a hot issue. Based on the doubly interval-censored ...data model, we assume that the incubation period follows lognormal and Gamma distribution, and estimate the parameters of the incubation period of COVID-19 by adopting the maximum likelihood estimation, expectation maximization algorithm and a newly proposed algorithm (expectation mostly conditional maximization algorithm, referred as ECIMM). The main innovation of this paper lies in two aspects: Firstly, we regard the sample data of the incubation period as the doubly interval-censored data without unnecessary data simplification to improve the accuracy and credibility of the results; secondly, our new ECIMM algorithm enjoys better convergence and universality compared with others. With the framework of this paper, we conclude that 14-day quarantine period can largely interrupt the transmission of COVID-19, however, people who need specially monitoring should be isolated for about 20 days for the sake of safety. The results provide some suggestions for the prevention and control of COVID-19. The newly proposed ECIMM algorithm can also be used to deal with the doubly interval-censored data model appearing in various fields.
Acute kidney injury (AKI) is a syndrome of abrupt loss of renal functions. The underlying pathological mechanisms of AKI remain largely unknown. BCL2-interacting protein 3 (BNIP3) has dual functions ...of regulating cell death and mitophagy, but its pathophysiological role in AKI remains unclear. Here, we demonstrated an increase of BNIP3 expression in cultured renal proximal tubular epithelial cells following oxygen-glucose deprivation-reperfusion (OGD-R) and in renal tubules after renal ischemia-reperfusion (IR)-induced injury in mice. Functionally, silencing Bnip3 by specific short hairpin RNAs in cultured renal tubular cells reduced OGD-R-induced mitophagy, and potentiated OGD-R-induced cell death. In vivo, Bnip3 knockout worsened renal IR injury, as manifested by more severe renal dysfunction and tissue injury. We further showed that Bnip3 knockout reduced mitophagy, which resulted in the accumulation of damaged mitochondria, increased production of reactive oxygen species, and enhanced cell death and inflammatory response in kidneys following renal IR. Taken together, these findings suggest that BNIP3-mediated mitophagy has a critical role in mitochondrial quality control and tubular cell survival during AKI.
The robustness of carbon nanomaterials and their potential for ultrahigh permeability has drawn substantial interest for separation processes. However, graphene oxide membranes (GOms) have ...demonstrated limited viability due to instabilities in their microstructure that lead to failure under cross-flow conditions and applied hydraulic pressure. Here we present a highly stable and ultrapermeable zeolitic imidazolate framework-8 (ZIF-8)-nanocrystal-hybridized GOm that is prepared by ice templating and subsequent in situ crystallization of ZIF-8 at the nanosheet edges. The selective growth of ZIF-8 in the microporous defects enlarges the interlayer spacings while also imparting mechanical integrity to the laminate framework, thus producing a stable microstructure capable of maintaining a water permeability of 60 l m
h
bar
(30-fold higher than GOm) for 180 h. Furthermore, the mitigation of microporous defects via ZIF-8 growth increased the permselectivity of methyl blue molecules sixfold. Low-field nuclear magnetic resonance was employed to characterize the porous structure of our membranes and confirm the tailored growth of ZIF-8. Our technique for tuning the membrane microstructure opens opportunities for developing next-generation nanofiltration membranes.
Electronic skins (E-skins) have attracted great research interest because of their promising applications in stretchable optoelectronics, soft robotics, and personalized healthcare devices. However, ...it remains a great challenge to fabricate E-skin devices that meet strict practical requirements such as high sensitivity, low-power operation and noise-proof ability. Here, we developed a novel elastic ionic polyacrylamide hydrogel (EIPH) with a high capacitance for the development of low-voltage organic thin-film transistor (OTFT) pressure sensors. The EIPH was prepared by photopolymerization of an acrylamide monomer in an aqueous solution of poly (acrylic acid) and CaCl2 and was then in situ micropatterned on an indium-tin oxide electrode. The fabricated capacitive sensor with 10-µm-wide EIPH micropillar structures achieved a high sensitivity of 2.33 kPa−1 with a capacitance sensitivity of 103.8 nF/kPa. This capacitance sensitivity is more than 100 times higher than that of conventional capacitive pressure sensors due to the formation of an electrical double layer. The micropatterned EIPH was adopted as a dielectric layer in the fabrication of the OTFT-based pressure sensors. Such an EIPH-based OTFT pressure sensor not only greatly enhanced the sensitivity, i.e., 7.7 times higher than its capacitive counterparts, but also largely reduced the operation voltage to 2 V.
An elastic ionic hydrogel is prepared and micropatterned to fabricate capacitive and organic thin-film transistor (OTFT) pressure sensors. By virtue of high elasticity and ionic conducting ability, the microstructures of the hydrogel can enhance the capacitive pressure sensor's performances in terms of operation voltage and sensitivity. Moreover, the microstructured hydrogel provides OTFT-based pressure sensors with an ideal dielectric layer, which can not only greatly enhance sensitivity but also dramatically reduce operation voltage. Display omitted
•An elastic ionic polyacrylamide hydrogels (EIPH) with high elasticity and ionic conducting ability is prepared.•The EIPH is in situ optically micropatterned on electrodes to fabricate flexible capacitive pressure sensors.•By virtue of the formaiton of electrical double layer, high-performance capacitive pressure sensors are fabricated.•Flexible OTFT pressure sensors with enhanced sensitivity and reduced operation voltage are demonstrated.
The papacy’s authority and standing in the sixteenth century were harmed by the Martin Luther Reformation and the sacking of Rome. In order to uphold the legitimacy of the papal theocracy and to ...restore the papacy’s cultural and intellectual authority, Pope Paul III brought back carnival celebrations in Rome. Paul III, a reformer, maintained an image of the pope as a spiritual leader who was “merciful” and “peaceful” using clever imagery; for instance, staging a “mask” procession which unites people while minimising ethnic and national disparities, thereby fostering a sense of community within the Catholic community. Reinforcing himself as a religious leader, Paul III was careful with the image of the papal monarchy in order to preserve the unity and independence of the Papal States. In the carnival floats, the pope introduced elements of pagan mythology, comparing himself to the consuls of ancient Rome to strengthen the pope’s ties with society. He adopted Janus (the double-faced god) and Apollo (the sun god) to create a secular image of the pope as the patron saint of Rome. On the one hand, the spiritual image of Pope Paul III as a religious leader was prominent in the carnival celebrations, and on the other hand, the secular image of the pope helped to consolidate the authority of the pope and external defendant of the Papal States. The dual spiritual and secular image of the pope underwent constant changes during the celebrations, a process of tension that helped him to overcome, in part, the political and religious challenges of the early modern period and reflected the transitional and dual nature of the Catholic Church at the time.
Mitochondria are essential for the activity, function and viability of eukaryotic cells and mitochondrial dysfunction is involved in the pathogenesis of acute kidney injury (AKI) and chronic kidney ...disease, as well as in abnormal kidney repair after AKI. Multiple quality control mechanisms, including antioxidant defence, protein quality control, mitochondrial DNA repair, mitochondrial dynamics, mitophagy and mitochondrial biogenesis, have evolved to preserve mitochondrial homeostasis under physiological and pathological conditions. Loss of these mechanisms may induce mitochondrial damage and dysfunction, leading to cell death, tissue injury and, potentially, organ failure. Accumulating evidence suggests a role of disturbances in mitochondrial quality control in the pathogenesis of AKI, incomplete or maladaptive kidney repair and chronic kidney disease. Moreover, specific interventions that target mitochondrial quality control mechanisms to preserve and restore mitochondrial function have emerged as promising therapeutic strategies to prevent and treat kidney injury and accelerate kidney repair. However, clinical translation of these findings is challenging owing to potential adverse effects, unclear mechanisms of action and a lack of knowledge of the specific roles and regulation of mitochondrial quality control mechanisms in kidney resident and circulating cell types during injury and repair of the kidney.
•Up-to-date development of fiber-optic chemical sensors and biosensors are reviewed.•The role of sensing film in fiber-optic sensors are highlighted.•The fabrication of high-performance fiber-optic ...sensors are emphasized.•Combination of optical fibers with micro/nano-technologies are commented.
The Internet-of-Things (IoT) has witnessed exponential growth over the past decade and will significantly reshape human life from every aspect, e.g., defense, environmental monitoring, energy, food safety, knowledge dissemination, healthcare and so on. Fiber-optic sensors, with both communication and sensing functions, have become a bridge to connect people and the whole world, so they are essential parts for accelerating the development of the IoT. Fiber-optic sensors possess the capability of translating a change of target analyte into optical signals and subsequently transmit an optical signal with target analyte information to people, machines or systems in real-time, even from a long distance. Therefore, exploration of high-performance fiber-optic chemical sensors and biosensors could significantly promote the development of the IoT. This review paper presents the foundations of fiber-optic chemical sensing or biosensing, including the sensing mechanisms of various fiber-optic sensors, sensing materials and the novel techniques for sensing materials deposition. Furthermore, recent developments on fiber-optic chemical sensors and biosensors are summarized, analyzed and discussed. Finally, the strategies and guidelines to further promote the development of fiber-optic sensors are also discussed.
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