Self-assembling peptide semiconductors Tao, Kai; Makam, Pandeeswar; Aizen, Ruth ...
Science (American Association for the Advancement of Science),
11/2017, Letnik:
358, Številka:
6365
Journal Article
Recenzirano
Odprti dostop
Semiconductors are central to the modern electronics and optics industries. Conventional semiconductive materials bear inherent limitations, especially in emerging fields such as interfacing with ...biological systems and bottom-up fabrication. A promising candidate for bioinspired and durable nanoscale semiconductors is the family of self-assembled nanostructures comprising short peptides. The highly ordered and directional intermolecular π-π interactions and hydrogen-bonding network allow the formation of quantum confined structures within the peptide self-assemblies, thus decreasing the band gaps of the superstructures into semiconductor regions. As a result of the diverse architectures and ease of modification of peptide self-assemblies, their semiconductivity can be readily tuned, doped, and functionalized. Therefore, this family of electroactive supramolecular materials may bridge the gap between the inorganic semiconductor world and biological systems.
To better understand the subsurface behavior of subducting slabs and their relation to the tectonic evolution of the overriding plate, we conduct a full waveform inversion on a large data set to ...determine a high‐resolution seismic model, FWEA18 (Full Waveform inversion of East Asia in 2018), of the upper mantle beneath eastern Asia. FWEA18 reveals sharper, more intense high‐velocity slabs in the upper mantle under the southern Kuril, Japan, and Ryukyu arcs, than previous studies have found. The subducting Pacific plate is imaged as a roughly 100 km thick high‐velocity slab to near 550 km depth indicating relatively little deformation. Stagnation near 600 km depth is observed over horizontal distances of 600 km or less. The Pacific plate we image accounts for roughly 25 Myr of subduction with older slab likely located in the lower mantle. The Philippine plate, subducting beneath the Ryukyu Islands, has a clear termination at about 450 km depth. This may indicate a tearing event in the past or that less Philippine Sea plate has subducted than previously thought. We found a double‐layer high‐velocity anomaly above and below 660 km under the Yellow Sea and eastern coast of North China. This may correspond to parts of the Philippine Sea plate that detached in the past and Pacific plate that have intersected at depth or a complicated behavior of the Pacific plate at that depth. Slow cylindrical anomalies cross the entire upper mantle are imaged beneath major Holocene volcanoes, which are likely upwellings associated with the edges of deep slabs that are entering the lower mantle.
Key Points
High‐resolution 3‐D full waveform inversion for P‐velocities and S‐velocities reveals sharper and more intense mantle structures beneath East Asia
Subducting Pacific and Philippine Sea plates show little deformation until 550 km depth where the slabs stagnate and thicken
Narrow cylindrical slow anomalies beneath major Holocene volcanoes are rooted adjacent to where deep slabs enter the lower mantle
Amino acids and short peptides modified with the 9-fluorenylmethyloxycarbonyl (Fmoc) group possess eminent self-assembly features and show distinct potential for applications due to the inherent ...hydrophobicity and aromaticity of the Fmoc moiety which can promote the association of building blocks. Given the extensive study and numerous publications in this field, it is necessary to summarize the recent progress concerning these important bio-inspired building blocks. Therefore, in this review, we explore the self-organization of this class of functional molecules from three aspects, i.e., Fmoc-modified individual amino acids, Fmoc-modified di- and tripeptides, and Fmoc-modified tetra- and pentapeptides. The relevant properties and applications related to cell cultivation, bio-templating, optical, drug delivery, catalytic, therapeutic and antibiotic properties are subsequently summarized. Finally, some existing questions impeding the development of Fmoc-modified simple biomolecules are discussed, and corresponding strategies and outlooks are suggested.
When analytic quasi-periodic cocycles are defined on a high dimension torus, their Lyapunov exponents have perturbative positivity and continuity. In this article, we study a class of analytic ...quasi-periodic Jacobi cocycles defined on a two dimension torus. We show that in the non-perturbative large coupling regimes, the Lyapunov exponent is positive for any frequency and weak Holder continuous for the full-measured frequency.
For more information see https://ejde.math.txstate.edu/Volumes/2020/51/abstr.html
Bioinspired nanostructures can be the ideal functional smart materials to bridge the fundamental biology, biomedicine and nanobiotechnology fields. Among them, short peptides are among the most ...preferred building blocks as they can self-assemble to form versatile supramolecular architectures displaying unique physical and chemical properties, including intriguing optical features. Herein, we discuss the progress made over the past few decades in the design and characterization of optical short peptide nanomaterials, focusing on their intrinsic photoluminescent and waveguiding performances, along with the diverse modulation strategies. We review the complicated optical properties and the advanced applications of photoactive short peptide self-assemblies, including photocatalysis, as well as photothermal and photodynamic therapy. The diverse advantages of photoactive short peptide self-assemblies, such as eco-friendliness, morphological and functional flexibility, and ease of preparation and modification, endow them with the capability to potentially serve as next-generation, bio-organic optical materials, allowing the bridging of the optics world and the nanobiotechnology field.
Ionic hydrogels, a class of intrinsically stretchable and conductive materials, are widely used in soft electronics. However, the easy freezing and drying of water-based hydrogels significantly limit ...their long-term stability. Here, a facile solvent-replacement strategy is developed to fabricate ethylene glycol (Eg)/glycerol (Gl)-water binary antifreezing and antidrying organohydrogels for ultrastretchable and sensitive strain sensing within a wide temperature range. Because of the ready formation of strong hydrogen bonds between Eg/Gl and water molecules, the organohydrogels gain exceptional freezing and drying tolerance with retained deformability, conductivity, and self-healing ability even stay at extreme temperature for a long time. Thus, the fabricated strain sensor displays a gauge factor of 6, which is much higher than previously reported values for hydrogel-based strain sensors. Furthermore, the strain sensor exhibits a relatively wide strain range (0.5–950%) even at −18 °C. Various human motions with different strain levels are monitored by the strain sensor with good stability and repeatability from −18 to 25 °C. The organohydrogels maintained the strain sensing capability when exposed to ambient air for nine months. This work provides new insight into the fabrication of stable, ultrastretchable, and ultrasensitive strain sensors using chemically modified organohydrogel for emerging wearable electronics.
Elderly cancer patients are at particularly high risk for malnutrition because both the disease and the old age threaten their nutritional status. The Global Leadership Initiative on Malnutrition ...(GLIM) released new universal criteria for diagnosing and grading malnutrition, but the validation of these criteria in elderly cancer population is not well documented. Our objective was to investigate the application of the GLIM criteria in nutrition assessment and survival prediction in elderly cancer patients.
This retrospective cohort analysis was conducted on a primary cohort of 1192 cancer patients aged 65 years or older enrolled from a multi-institutional registry, and a validation cohort of 300 elderly cancer patients treated at the First Affiliated Hospital of Sun Yat-sen University. Patients considered at-risk for malnutrition based on the NRS-2002 were assessed using the GLIM criteria. The association between the nutritional status and patients' overall survival (OS) was then analyzed by the Kaplan–Meier method and a Cox model. A nomogram was also established that included additional independent clinical prognostic variables. To determine the predictive accuracy and discriminatory capacity of the nomogram, the C-index, receiver operating characteristic (ROC) curve and calibration curve were evaluated.
The percentage of patients considered “at-risk” for malnutrition was 64.8% and 67.3% for the primary and validation cohorts, respectively. GLIM-defined malnutrition was diagnosed in 48.4% of patients in the primary cohort and 46.0% in the validation cohort. In the primary cohort, patients at risk of malnutrition (NRS-2002 ≥ 3) showed a worse OS than those with a NRS-2002 < 3 (HR 1.34, 1.10–1.64; p = 0.003). Additionally, patients with GLIM-defined severe malnutrition (HR1.71, 1.37–2.14; p < 0.001) or moderate malnutrition (HR1.35, 1.09–1.66; p = 0.006) showed a significantly shorter OS compared to those without malnutrition. The nomogram incorporating the domains of the GLIM with other variables was accurate, especially for predicting the 1- and 2-year overall survival rates.
The GLIM criteria can be used in elderly cancer patients not only to assess malnutrition, but also to predict survival outcome. The nomogram developed based on the GLIM domains can provide a more accurate prediction of the prognosis than existing systems.
In this article, we study the continuity of the Lyapunov exponent of discrete analytic Jacobi operators with the skew-shift mapping. We prove that the Lyapunov exponent is weak Holder continuous in E ...for any Diophantine frequency in the large coupling regimes.
Carbon nanocoils (CNCs) are employed to fabricate fast, high-resolution, and reversible humidity sensor based on a flexible liquid crystal polymer (LCP) substrate. The humidity sensor displays ...fast-response (1.9 s) and recovery time (1.5 s), a broad relative humidity (RH) detection range (4–95%), linearity, repeatability, and stability. The rapid response and recovery are considered to benefit from the hydrophobic effect of the LCP substrate and high purity of the CNCs, which give rise to weak physical adsorption. Meanwhile, the high sensitivity results from both the unique helical structure of CNCs and the microporous structure of the LCP substrate. The distinctive structure-related properties enable the sensor to reliably perceive an extremely small RH variation of 0.8%, which is too small to be detected by most humidity sensors reported previously. These features allow the sensor to monitor a variety of important human activities, such as respiration, speaking, blowing, and noncontact fingertip sensation, accurately. Furthermore, different human physical conditions can be distinguished by recognizing the respiration response patterns. In addition, the long-term operation and mechanical bending do not adversely affect the sensing performance.
Sepsis is a life‐threatening organ dysfunction syndrome, and liver is a susceptible target organ in sepsis, because the activation of inflammatory pathways contributes to septic liver injury. ...Oxidative stress has been documented to participate in septic liver injury, because it not only directly induces oxidative genotoxicity, but also exacerbates inflammatory pathways to potentiate damage of liver. Therefore, to ameliorate oxidative stress is promising for protecting liver in sepsis. Wogonin is the compound extracted from the medicinal plant Scutellaria baicalensis Geogi and was found to exert therapeutic effects in multiple inflammatory diseases via alleviation of oxidative stress. However, whether wogonin is able to mitigate septic liver injury remains unknown. Herein, we firstly proved that wogonin treatment could improve survival of mice with lipopolysaccharide (LPS)‐ or caecal ligation and puncture (CLP)‐induced sepsis, together with restoration of reduced body temperature and respiratory rate, and suppression of several pro‐inflammatory cytokines in circulation. Then, we found that wogonin effectively alleviated liver injury via potentiation of the anti‐oxidative capacity. To be specific, wogonin activated Nrf2 thereby promoting expressions of anti‐oxidative enzymes including NQO‐1, GST, HO‐1, SOD1 and SOD2 in hepatocytes. Moreover, wogonin‐induced Nrf2 activation could suppress NF‐κB‐regulated up‐regulation of pro‐inflammatory cytokines. Ultimately, we provided in vivo evidence that wogonin activated Nrf2 signalling, potentiated anti‐oxidative enzymes and inhibited NF‐κB‐regulated pro‐inflammatory signalling. Taken together, this study demonstrates that wogonin can be the potential therapeutic agent for alleviating liver injury in sepsis by simultaneously ameliorating oxidative stress and inflammatory response through the activation of Nrf2.
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