A Sunlight-Degradable Autonomous Self-Healing Supramolecular Elastomer for Flexible Electronic Devices

Preparing an autonomous self-healing supramolecular elastomer with sunlight degradability is still a challenging task in related fields. In this work, we report a supramolecular elastomer by using the classic host–guest complexation of visible-light-photolabile picolinium-containing adamantanes (Ad) and β-cyclodextrin nanogels (β-CD). The as-synthesized elastomer possesses merits of high mechanical strength, excellent stretchability (>1500% strain), efficient self-healing (>85% at 60 min), ultrastability against electrolytes, and photodegradation properties, implying versatile applications in flexible and stretchable electronics. As proofs-of-concept, self-healable strain and pressure sensors using conductive elastomers are first fabricated, which feature exceptionally high sensitivity (e.g., 0.1% in capacitance at 0.2 kPa) and fast response to detect human body motions. A degradable and flexible supercapacitor is also fabricated using the conductive elastomer as the flexible matrix. Remarkably, both the elastomer and this supercapacitor can be degraded upon the exposure to sunlight irradiation in 48 h at very mild conditions. Therefore, it is anticipated that such a novel strategy and the as-prepared supramolecular elastomer can inspire further applications in the multidisciplinary fields of materials science, electronics, etc

A Sunlight-Degradable Autonomous Self-Healing Supramolecular Elastomer for Flexible Electronic Devices

Preparing an autonomous self-healing supramolecular elastomer with sunlight degradability is still a challenging task in related fields. In this work, we report a supramolecular elastomer by using the classic host–guest complexation of visible-light-photolabile picolinium-containing adamantanes (Ad) and β-cyclodextrin nanogels (β-CD). The as-synthesized elastomer possesses merits of high mechanical strength, excellent stretchability (>1500% strain), efficient self-healing (>85% at 60 min), ultrastability against electrolytes, and photodegradation properties, implying versatile applications in flexible and stretchable electronics. As proofs-of-concept, self-healable strain and pressure sensors using conductive elastomers are first fabricated, which feature exceptionally high sensitivity (e.g., 0.1% in capacitance at 0.2 kPa) and fast response to detect human body motions. A degradable and flexible supercapacitor is also fabricated using the conductive elastomer as the flexible matrix. Remarkably, both the elastomer and this supercapacitor can be degraded upon the exposure to sunlight irradiation in 48 h at very mild conditions. Therefore, it is anticipated that such a novel strategy and the as-prepared supramolecular elastomer can inspire further applications in the multidisciplinary fields of materials science, electronics, etc

Image_1.TIF

<p>Background: Hemorrhagic transformation, neurotoxicity, short treatment time windows, and other defects are considered as the major limitations for the thrombolytic therapy. This study is devoted to figure out whether Danhong injection (DHI) combined with tissue-plasminogen activator (t-PA) could extend the treatment time windows and ameliorate brain injury, hemorrhagic complication and BBB disruption after focal embolic stroke.</p><p>Methods:In vitro, the combined concentrations of DHI and t-PA were added to wells reacted with plasminogen and D-Val-Leu-Lys-AMC. The optimum ratio of the combination of DHI plus t-PA was explored by detecting relative fluorescent. In vivo experiments, we firstly investigated the optimal dose of t-PA and Danhong injection for focal embolic stroke. The neurological deficit score, infarct volume and brain edema were assessed. Secondly, we proved that the combination group extended the thrombolytic window for treatment of focal embolic stroke. The neurological deficit score, infarct volume, brain edema and hemorrhagic complication were assessed, while levels of BAX, Bcl-2 and caspase-3 in brain tissue were analyzed by real-time polymerase chain reaction. Finally, to ask whether combination therapy with DHI plus t-PA protected the blood–brain barrier in a rat model of focal embolic stroke, neurological deficit score, ELISA, RT-PCR, western blot and fluorescence were used to detect the indicators of blood–brain barrier, such as tight junction protein, blood–brain barrier permeability and related gene expression.</p><p>Results:In vitro, plasmin activity assays showed that the combination of t-PA with DHI at about 1:1.6 w/v ratio increased by almost 1.4-fold the plasmin-generating capability of t-PA. In vivo experiments, the results showed that the combination of Danhong injection (4 mL/kg) and t-PA (2.5 mg/kg) could extend the t-PA treatment time windows to 4.5 h. And the combination t-PA (2.5 mg/kg) with DHI (4 mL/kg) ameliorated neurological score, cerebral infarction, brain edema, brain hemorrhage, and BBB disruption.</p><p>Conclusion: Combination therapy with Danhong injection (4 mL/kg) plus t-PA (2.5 mg/kg) could extend the t-PA treatment time windows to 4.5 h, ameliorate BBB disruption, reduce infarction, brain swelling and hemorrhage after ischemic stroke.</p

Aptamer-Based K⁺ Sensor: Process of Aptamer Transforming into G‑Quadruplex

G-rich aptamers have been widely applied to develop various sensors for detecting proteins, small molecules, and cations, which is based on the target-induced conformational transfer from single strand to G-quadruplex. However, the transforming process is unclear. Here, with PW17 as an aptamer example, the forming process of G-quadruplex induced by K⁺ is investigated by circular dichroism spectroscopy, electrospray ionization mass spectroscopy, and native gel electrophoresis. The results demonstrate that PW17 undergoes a conformational transforming process from loose and unstable to compact and stable G-quadruplex, which is strictly K⁺ concentration-dependent. The process contains three stages: (1) K⁺ (<0.5 mM) could induce PW17 forming a loose and unstable G-quadruplex; (2) the compact and stable K⁺-stabilized G-quadruplex is almost formed when K⁺ is equal to or larger than 7 mM; and (3) when K⁺ ranges from 0.5 mM to 7 mM, the transformation of K⁺-stabilized PW17 from loose and unstable to compact and stable occurs. Interestingly, dimeric G-quadruplex through 5′-5′ stacking is involved in the forming process until completely formed at 40 mM K⁺. Moreover, the total process is thermodynamically controlled. With PW17 as a sensing probe and PPIX as a fluorescent probe for detection of K⁺, three linear fluorescent ranges are observed, which corresponds to the three forming stages of G-quadruplex. Clarifying the forming process provides a representative example to deeply understand and further design aptamer-based biosensers and logic devices

Ag₇Au₆ Cluster as a Potential Gas Sensor for CO, HCN, and NO Detection

Ag–Au bimetallic clusters have demonstrated extreme sensitivity, which can be theoretically explained by the conductivity change of the clusters induced by the absorption process, to molecules such as CO, H₂S, and so forth. Recently, a 13-atom alloy quantum cluster (Ag₇Au₆) has been experimentally synthesized and characterized. Here, the adsorption of CO, HCN, and NO on the Ag₇Au₆ cluster was investigated using density functional theory calculations in terms of geometric, energetic, and electronic properties to exploit its potential applications as gas sensors. It is found that the CO, HCN, and NO molecules can be chemisorbed on the Ag₇Au₆ cluster with exothermic adsorption energy (−0.474 ∼ −1.039 eV) and can lead to finite charge transfer. The electronic properties of the Ag₇Au₆ cluster present dramatic changes after the adsorption of the CO, HCN, and NO molecules, especially its electric conductivity. Thus, the Ag₇Au₆ cluster is expected to be a promising gas sensor for CO, HCN, and NO detection

Three-Dimensional Self-Assembly of Core/Shell-Like Nanostructures for High-Performance Nanocomposite Permanent Magnets

Core/shell nanostructures are fascinating for many advanced applications including strong permanent magnets, magnetic recording, and biotechnology. They are generally achieved via chemical approaches, but these techniques limit them to nanoparticles. Here, we describe a three-dimensional (3D) self-assembly of core/shell-like nanocomposite magnets, with hard-magnetic Nd₂Fe₁₄B core of ∼45 nm and soft-magnetic α-Fe shell of ∼13 nm, through a physical route. The resulting Nd₂Fe₁₄B/α-Fe core/shell-like nanostructure allows both large remanent magnetization and high coercivity, leading to a record-high energy product of 25 MGOe which reaches the theoretical limit for isotropic Nd₂Fe₁₄B/α-Fe nanocomposite magnets. Our approach is based on a sequential growth of the core and shell nanocrystals in an alloy melt. These results make an important step toward fabricating core/shell-like nanostructure in 3D materials

CuO/ZnO/Al₂O₃ Catalyst Prepared by Mechanical-Force-Driven Solid-State Ion Exchange and Its Excellent Catalytic Activity under Internal Cooling Condition

CuO/ZnO/Al₂O₃ catalysts were prepared by a mechanical-force-driven solid-state ion-exchange method, and their catalytic performance for methanol synthesis was investigated in a manufactured reactor with an internal cooling system. With the increasing of milling speed during ball-milling, the ion exchange between Cu²⁺ and Zn²⁺ in catalyst precursors is enhanced. After calcination, CuO nanoparticles are neighboring to ZnO nanoparticles and ZnO nanoparticles serve as spacers to prevent the agglomeration of CuO nanoparticles, leading to a cross-distribution of CuO and ZnO in catalysts. The as-prepared catalysts exhibit excellent catalytic activities, and the highest CO₂ conversion and CH₃OH yield at 240 °C and 4 MPa can reach 59.5% and 43.7%, respectively. The extraordinary catalytic performance can be attributed to both the cross-distribution of CuO and ZnO nanoparticles caused by solid-state ion exchange and the promotion of reversible CO₂ hydrogenation reaction toward methanol synthesis by the internal cooling system

Gonadotropin-Releasing Hormone for Preservation of Ovarian Function during Chemotherapy in Lymphoma Patients of Reproductive Age: A Summary Based on 434 Patients

<div><p>Background</p><p>Gonadotropin-releasing hormone agonists (GnRHa) might play a role in preserving ovarian function in lymphoma patients by inhibiting chemotherapy-induced ovarian follicular damage. However, studies of its clinical efficacy have reported conflicting results.</p> <p>Method</p><p>We conducted a meta-analysis to determine the effect of the preservation of ovarian function by administering GnRHa in young patients with lymphoma undergoing chemotherapy. Seven studies were identified that met inclusion criteria and comprised 434 patients assigned to GnRHa combined chemotherapy or chemotherapy alone.</p> <p>Results</p><p>The incidence of women with premature ovarian failure (POF) demonstrated a statistically significant difference in favor of the use of GnRHa (OR=0.32, 95% CI 0.13-0.77). In addition, the final level of FSH in the GnRH group was significantly lower than control group. (MD= -11.73, 95% CI,-22.25- -1.20), and the final level of AMH in the GnRH group was significantly higher than control group (MD=0.80; 95% CI, 0.61–0.98). However, there was no statistically significant difference between treatment and the control groups in the incidence of a spontaneous pregnancy (OR=1.11; 95% CI, 0.55–2.26).</p> <p>Conclusion</p><p>This meta-analysis suggests that GnRHa may be effective in protecting ovarian function during chemotherapy in lymphoma patients. More well-designed prospective studies are needed to carry out for further understanding of this topic.</p> </div

Sulfur-Doped Graphene Quantum Dots as a Novel Fluorescent Probe for Highly Selective and Sensitive Detection of Fe³⁺

Sulfur-doped graphene quantum dots (S-GQDs) with stable blue-green fluorescence were synthesized by one-step electrolysis of graphite in sodium <i>p</i>-toluenesulfonate aqueous solution. Compared with GQDs, the S-GQDs drastically improved the electronic properties and surface chemical reactivities, which exhibited a sensitive response to Fe³⁺. Therefore, the S-GQDs were used as an efficient fluorescent probe for highly selective detection of Fe³⁺. Upon increasing of Fe³⁺ concentration ranging from 0.01 to 0.70 μM, the fluorescence intensity of S-GQDs gradually decreased and reached a plateau at 0.90 μM. The difference in the fluorescence intensity of S-GQDs before and after adding Fe³⁺ was proportional to the concentration of Fe³⁺, and the calibration curve displayed linear regions over the range of 0–0.70 μM. The detection limit was 4.2 nM. Finally, this novel fluorescent probe was successfully applied to the direct analysis of Fe³⁺ in human serum, which presents potential applications in clinical diagnosis and may open a new way to the design of effective fluorescence probes for other biologically related targets

Na⁺‑Induced Conformational Change of Pb²⁺-Stabilized G‑Quadruplex and Its Influence on Pb²⁺ Detection

Here, we first find that Na⁺ can induce Pb²⁺-stabilized T30695 undergoing conformational transition from partly parallel to completely parallel, and further forming a dimeric G-quadruplex, which was characterized by circular dichroism (CD) spectroscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and native polyacrylamide gel electrophoresis (PAGE). Thermal denaturation experiments show that the transforming process is a thermodynamics-driven process. Furthermore, the presence of Na⁺ further improves the binding efficiency of Pb²⁺-stabilized T30695 with the fluorescent probe (such as ZnPPIX). Based on the fact, with a partially hybridized double-stranded DNA (ds-DNA) containing T30695 as a sensing probe and ZnPPIX as a fluorescence probe, the effect of Na⁺ on Pb²⁺ detection is subsequently investigated. The presence of Na⁺ (varied from 0.3 mM to 500 mM) simultaneously increases the read-out and background fluorescence, which results in a decreased signal-to-noise ratio and further leads to a decreased sensing performance (detection limits is increased to 120 nM). In order to avoid Na⁺ interference, a fully matched ds-DNA containing T30695 is utilized as a sensing probe to fix the background fluorescence, regardless of whether Na⁺ is present or not. Thus, a relatively lower detection limit (10 nM) in all Na⁺-containing real samples is achieved, respectively. Therefore, the paper provides a novel insight into the conformational changes in G-quadruplex and presents an efficient step to resolve the challenging problem about Pb²⁺ detection in Na⁺-containing real samples