Search

Aging is a risk factor for human health and quality of life. Screening and development of novel supplements and medications to combat aging and delay the incidence of age-related diseases are of great significance. In this study, salidroside (SA), a primary natural small molecule from Rhodiola rosea, was investigated regarding its effects on life and healthspan and the underlying molecular mechanism(s) of anti-aging and antioxidation. Our results showed that SA effectively prolonged lifespan and exhibited anti-aging and antioxidative properties. Computer-assisted methods, label-free interaction analysis, and in vitro assays showed that SA directly bound heat shock protein 90 (HSP90). Furthermore, SA significantly inhibited the ATPase activity of HSP90, affecting the interaction between HSP90 and its interacting proteins and the expression of downstream genes to regulate lifespan and the oxidative stress response. Our findings provided new insights into the pharmacological properties of SA across multiple species and its potential as an anti-aging drug.

This paper is concerned with the stabilization and event-triggered control for positive nonlinear systems in terms of Takagi–Sugeno (T–S) fuzzy models. By employing the unique positivity of positive systems, a new event-triggered mechanism is introduced to select necessary signals so that the communication resources can be saved effectively while guaranteeing the system performance. It is different from the traditional event-triggered mechanism that is designed in the quadratic form for general systems, the one adopted in this paper is in linear form which is beneficial to facilitate the stability analysis in terms of a linear copositive Lyapunov function. However, the tricky non-convex problem makes controller design extremely challenging. For handling this issue, the matrix decomposition technique plays a very important part in designing the feedback control law. Furthermore, improving the relaxation of the analysis results is another considerably vital but challenging issue. To break through this difficulty, an asynchronous premise re-construct method is presented to extract the information of membership functions (MFs), which is conducive to obtaining more relaxed stability and positivity analysis. Finally, the validity of this control strategy is illustrated by simulation examples.

This article studies the membership-function-dependent (MFD) stability and positivity analysis of positive interval type-2 (IT2) Takagi–Sugeno (T–S) fuzzy fault-tolerant control systems under the event-triggered control framework. Considering the fact that parameter uncertainties may exist in nonlinear plants, the IT2 T–S fuzzy model as an effective mathematical tool is employed to approximately express a complex positive system with nonlinearities and uncertainties. In order to save communication resources and improve the security of system operation, an event-triggered fault-tolerant (ETFT) control strategy is then designed based on the imperfectly premise matching concept. In addition, for capturing positivity characteristic and matching with the linear copositive Lyapunov function, a novel event-triggered condition in the 1-norm rather than in the 2-norm is developed to control the positive IT2 T–S fuzzy systems. Thereinto, the nonconvex problem as the first obstacle is required to be cleared since feasible solutions usually cannot be obtained based on the nonconvex conditions. For dealing with this problem, a valid approach is presented to conduct convexification with the help of a user-chosen constant vector. Besides, because of event-triggered action, the inherent mismatched issue of the premise variables of the fuzzy model and the ones of the fuzzy controller is encountered. Fortunately, the advanced MFD analysis, which is capable of bringing the information contained in the membership functions into the stability and positivity conditions, provides an effective strategy to remove this barrier. Consequently, relaxed results that can accomplish the stability and positivity for wider positive systems are developed and displayed in sum-of-squares form. Detailed simulation results are given to clarify the effectiveness of the designed ETFT control method.

As an endocrine disruptor, bisphenol A (BPA) is a severe threat to human health. In this study, nitrate (NO3−) photolysis with a low-pressure UV lamp (LP-UV) was employed to degrade BPA in different aqueous solutions. Results showed that BPA could be decomposed efficiently in the UV/NO3−process. Moreover, the contributions of UV irradiation (4.1%), OH (52.7%), and reactive nitrogen species (43.2%) were obtained. The observed rate constant of BPA degradation (kobs) increased with NO3−concentration since more active species were generated in high NO3−concentration. The BPA degradation rate was significantly accelerated as the pH value rose. This was ascribed to the increase of the molar absorption coefficient and the amount of ionic BPA under alkaline conditions. kobsdeclining with increasing BPA concentration resulted from the inner filter effect and the competition of more generated intermediate products. The increasing kobswith the addition of HCO3−/CO32−(0–10 mM) was explained as the accumulation of NO2in the presence of HCO3−/CO32−in UV/NO3−process. The effect of Cl−(0–20 mM) could be ignored in this study, which suggested that reactive chlorine radicals degraded BPA effectively. The kobsreduced acutely when NOM (0–5 mgC L−1) existed in the solution, and this could be ascribed to the dual roles of the NOM inner filter effect and reactive radical scavenging effect. Further, several degradation products were detected, and possible transformation pathways were put forward. Remarkably, the acute toxicity of BPA was slightly enhanced then decayed in the UV/NO3−process.

Background:Limbal stem cell deficiency (LSCD) is a refractory ocular surface disorder characterized by progressive corneal epithelial degeneration, conjunctivalization, and neovascularization, potentially leading to blindness. There are currently no effective therapeutic options for patients experiencing routine symptomatic treatment failure. Transplantation of amniotic membrane (AM) with adherent stem cells (but not bare AM transplantation alone) has shown promise in preclinical studies for ocular surface restoration. A major limitation, however, is finding a reliable stem cell source. Stem cells can be isolated from the peripheral blood mononuclear cell (PBMC) population, and these PBMC-derived stem cells have numerous advantages over allogeneic and other autologous stem cell types for therapeutic application, including relative ease of acquisition, nonimmunogenicity, and the absence of ethical issues associated with embryonic stem cells.Experiment:We examined the efficacy of autologous PBMC−AM sheet cultures combined with postoperative antiangiogenesis treatment for corneal restoration in LSCD model rabbits. Rabbit PBMCs (rPBMCs) were isolated, labeled with EdU for in vivotracing, and then cultured on AMs in conditioned medium before transplantation. Rabbits were transplanted with bare AMs (group 1), rPBMC−AM sheets (group 2), or rPBMC−AM sheets plus postoperative treatment with the vascular endothelial growth factor antagonist bevacizumab (group 3). Corneal opacity and neovascularization were monitored by slit-lamp imaging for 8 weeks and corneas were examined histologically at 1 and 2 months.Results:Corneal opacity decreased in all three groups over 8 weeks, but was significantly lower in group 2 and even lower in group 3. Corneal neovascularization was significantly higher in group 1 throughout the observation period, and significantly lower in group 3 than group 1 and 2 by 8 weeks post-transplant. At 4 weeks, the corneal surface completed epithelialization (although thinner than normal) in group 3 but still patchy in groups 1 and 2. By 8 weeks, the epithelium in group 3 was complete and smooth, resembling a normal epithelium. Integrin β1 as a progenitor marker was also generally higher in groups 2 and 3.Conclusions:Autologous rPBMC−AM sheets with post-transplant topical bevacizumab can effectively facilitate corneal epithelium recovery in a LSCD model, suggesting clinical utility for LSCD-related ocular surface diseases.Impact statementLimbal stem cell deficiency (LSCD) increases corneal opacity and vascularization, resulting in severe visual impairment or even blindness. Traditional surgical limbal transplant is currently the main treatment option for LSCD, but carries the risks of rejection and immunosuppressant side effects. Autologous stem cell-based therapy is a promising alternative approach, but a reliable stem cell source is a major limitation. We report that transplantation of autologous rabbit peripheral blood mononuclear cell−amniotic membrane sheets plus antivascular endothelial growth factor restored avascular transparent cornea in a rabbit LSCD model. These results demonstrate a potentially effective approach for ocular surface reconstruction in bilateral LSCD.

A new photoinitiating system for the metal-free preparation of conjugated microporous polymers (CMPs) is reported. In this approach, irradiation of solutions containing an electroactive monomer, possessing both carbazole and fluorene units, 9,9′-(9,9-dihexyl-9H-fluorene-2,7-diyl)bis-9H-carbazole (CFD), and the iodonium salt (Ph2I+PF6–) as the oxidizing agent resulted in the formation of CMPs. Photoinduced step-growth polymerization proceeded through the successive electron transfer between the excited CFD and iodonium salt, proton release, and coupling reactions. The polymers formed were characterized by FT-IR and 1H NMR analyses. The electrochemical and optical properties of CMPs before and after the dedoping process were evaluated by cyclic voltammetry, differential pulse voltammetry, and UV–vis absorption and photoluminescence techniques. The porous structure of the obtained polymers was confirmed by atomic force microscopy and scanning electron microscopy studies.

A method of sucrose concentration detection based on surface plasmon resonance is proposed. Thus, what we believe to be a novel prism coupling structure is designed for a sucrose concentration sensor utilizing the unique feature of graphene oxide to sucrose in water, and a ${{\text{MoS}}_2}$MoS_2-graphene oxide hybrid nanofilm is chosen to enhance surface plasmon resonance based on Au nanoparticles. The thickness of each layer for the designed structure is analyzed to get the optimal value by the finite element method, so that the sensitivity of the sucrose concentration sensor is able to be improved greatly. The optimal thickness of each layer is given, for which the sensitivity of the surface plasmon resonance sucrose concentration sensor can reach as high as 0.16°/% concentration within the detection range of sucrose concentration, 0%–70% concentration. The relationship between the sucrose concentration and the surface plasmon resonance angle are obtained within the detection range of the sucrose concentration.

Banded iron formations are critical to track changes in Archaean to Palaeoproterozoic ocean chemistry, with deposition triggered by water column iron oxidation. Recently, however, it was suggested that reduced iron minerals were the primary precipitates, and these were subsequently oxidized by oxygen-bearing groundwater. If true, this would cast doubt on our understanding of how banded iron formations were deposited and their ability to record early ocean chemistry. Here we present a hydrogeological box model, based on the approximately 2.5 billion year old Hamersley Basin of Western Australia, developed to evaluate the plausibility of secondary iron oxidation. The box model calculates the time required for groundwater to flux enough oxygen through the basin to oxidize a given amount of ferrous iron. Less than 9% of nearly four million model iterations returned oxidation times less than the age of the basin. Successful simulations required simultaneously steep hydraulic gradients, high permeability and elevated oxygen concentrations. Our simulations show that the postdepositional oxidation of large banded iron formations is unlikely, except on a limited scale (that is, during secondary ore formation), and that oxidized iron phases were probably the precursor to large Palaeoproterozoic banded iron formations. Banded iron formations could not have formed by postdepositional oxidation, according to four million hydrogeological box model iterations that failed to reproduce secondary oxidation on reasonable timescales.

Developing efficient unimolecular visible light-emitting diode (LED) light photoinitiators (PIs) with photobleaching capability, which are essential for various biomedical applications and photopolymerization of thick materials, remains a great challenge. Herein, we demonstrate the synthesis of a series of novel PIs, containing coumarin moieties as chromophores and oxime ester groups as initiation functionalities and explore their structure–activity relationship. The investigated oxime esters can effectively induce acrylates and thiol-based click photopolymerization under 450 nm visible LED light irradiation. The initiator O-3exhibited excellent photobleaching capability and enabled photopolymerization of thick materials (∼4.8 mm). The efficient unimolecular photobleachable initiators show great potential in dental materials and 3D printings.

The existing full-span models of the tiltrotor aircraft adopted the rigid blade model without considering the coupling relationship among the elastic blade, wing and fuselage. To overcome the limitations of the existing full-span models and improve the precision of aeroelastic analysis of tiltrotor aircraft in forward flight, the aeroelastic stability analysis model of full-span tiltrotor aircraft in forward flight has been presented in this paper by considering the coupling among elastic blade, wing, fuselage and various components. The analytical model is validated by comparing with the calculation results and experimental data in the existing references. The influence of some structural parameters, such as the fuselage degrees of freedom, relative displacement between the hub center and the gravity center, and nacelle length, on the system stability is also investigated. The results show that the fuselage degrees of freedom decrease the critical stability velocity of tiltrotor aircraft, and the variation of the structural parameters has great influence on the system stability, and the instability form of system can change between the anti-symmetric and symmetric wing motions of vertical and chordwise bending.

Limbal stem cell defect model is an important animal model that provides a basis for the study of ocular surface diseases. The rabbit cornea is of moderate size and is widely used in such studies as an experimental animal model. At present, the main modeling methods are alkali burns, and corneal limbus girdling and corneal epithelium doctoring. Each method has its own characteristics. In this study, we observed rabbit models with severe ocular surface defect established by the two methods and changes after amniotic membrane transplantation. In the first, second, third, and fourth week after operation, the clinical manifestations, corneal transparency, and new vessels were observed according to the standard rating scale of ocular surface, compared between the two methods, and then statistically analyzed. In the fourth week after operation, the rabbits were sacrificed and their corneas and corneal limbus were extracted from sclera, embedded by optimum cutting temperature compound, frozen, and sliced for hematoxylin and eosin staining and pathological examination. There were two groups in this study. Group 1 (alkali burns) had more severe complications, such as, conjunctiva, nubecula, new vessel hyperplasia, and so on, compared to group 2 (corneal limbus girdling and corneal epithelium doctoring). In addition, there were striking differences in corneal transparency and new vessels between the two groups (p< 0.05). Corneal transparency in group 1 was lower than in group 2. New vessels in group 1 were less in the first 2 weeks, but obviously increased compared to group 2 in the subsequent weeks. Alkaline burn could be used to study new vessel hyperplasia, while corneal limbus girdling and corneal epithelium doctoring are more suitable for studying stem cell transdifferentiation, interactive roles of stem cells and microenvironment, and so on.

Fluorinated polycarbonate-based UV-curable polyurethane acrylate (F-PCUA) was synthesized by incorporating 1H, 1H, 2H, 2H-Perfluoro-1-octanol to the end of polycarbonate-based PUA chains. The structure of F-PCUA was determined by 1H-NMR, 19F-NMR, and FTIR analyses. The physical, surface, and thermal properties of F-PCUA were also examined. The F-PCUA was used as a hydrophobic additive in PUA coatings, and the water and oil wettability of the UV-cured film was investigated by contact angle measurements. The results showed that the coating system had great hydrophobicity. Furthermore, X-ray photoelectron spectroscopy research confirmed that a hydrophobic fluorine-enriched surface was obtained in the coating system. Moreover, the mechanical and chemical properties of the hydrophobic coatings did not show deterioration with the introduction of elemental F.

Abstract: In this work, the terahertz (THz) electromotive force (EMF) of the surface plasmon (SP) electric field and field strength was investigated in its propagation direction. Based on the nanowires structure, we introduced physical models which were light wave energy of surface plasmon polariton (SPP) pulse and the variation of EMF changes in the active condition. Results of theory and verification showed SPP generated EMF with 10−2–10 V among wire radii of 5–30 nm; the electric field was up to 105–106 V/cm in the radius of 5 nm; the electric field intensity induced localization at λ=850 nm, and at the same time light intensity amplified 40 times. The characteristics which are femtosecond SPP pulse response and force-field amplifier in this work are significant for nonlinear spectroscopy research.

Grafting is a popular approach for adjusting the properties and functionalization of various surfaces. Conventional photoinduced grafting has been utilized on flat surfaces, porous monoliths, and hydrogels. By masking or illuminating only a portion of the sample, a certain degree of spatial and temporal control is possible, but the ability to use grafting to pattern in 3D is limited. Here, the laser‐induced photolysis of an aromatic azide compound is employed for true 3D photografting within a poly(ethylene glycol) (PEG)‐based matrix. Since the multiphoton interaction occurs only in a confined area within the laser focal spot, the localized immobilization of a selected molecule with high spatial resolution in 3D is possible. In contrast to the widely utilized chain‐growth polymerization‐based grafting, the approach is characterized by a single‐molecule insertion mechanism. Successful binding of the fluorophore is confirmed by laser scanning microscopy. To test for the presence of latent azides and to determine the suitability for additional postmodification with arbitrary functional groups, the sample is further subjected to copper‐catalyzed alkyne click‐reaction conditions. The described 3D photografting method is simple, highly efficient, and universal. The presented results demonstrate the great potential of multiphoton‐induced grafting for 3D site‐specific functionalization.

The generation of high-power green laser is important for the numerous applications in industry, medicine, research and even entertainment. In addition, mode-locked lasers operating at ~100 MHz repetition rate, are particularly attractive for nonlinear optics and spectroscopy. Characteristics of high-power, mode-locking green radiation obtained by Nd:YVO4at 1064nm in the nonlinear crystals of PPKTP are studied. Two identical highly efficient diode-pumped laser heads placed in a plane-plane resonator are used for the input laser based on theoretically investigation of the thermally stable region of Nd:YVO4rod. The PPKTP crystal of Brewster-cut is used in the external cavity configuration, the cavity losses is significantly smaller than for an antireflection(AR) coated crystal cut for normal incident, however, the effective nonlinearity is reduction. Frequency doubling nonlinear mirror(FDNLM) based on intensity dependent reflection in the laser cavity is used for the laser mode-locking. A stable green output power of 510W with pulse repetition rate of 100MHz and net conversion efficiency of =50% at an input mode-matched power of 2KW are obtained. Meanwhile, thermal effects in the nonlinear crystal severely limit the efficiency of the laser configuration when using high pump power.

Thiol-ene photopolymerization has been a versatile tool for polymer synthesis. However, deep photopolymerization of the thiol-ene system still remains a great challenge due to the light-intensity gradient. Using near-infrared light as an excitation source and upconversion nanoparticles as internal lamps, we report a generic and efficient strategy to realize deep thiol-ene photopolymerization. More than 8 cm of photopolymerization depth combined with high functionality conversion was obtained in 40 s. The maximum temperature of about 110 °C during upconversion nanoparticle (UCNP)-assisted photopolymerization is comparable to or lower than that of some reported frontal photopolymerizations applied in the preparation of functional polymer composites and biomaterials.More than 8 cm of thiol-ene photopolymerization depth combined with high functionality conversion was obtained in 40 s using near-infrared light as an excitation source and upconversion nanoparticles as internal lamps.

We design custom-shaped modes for a sixfold symmetric photonic quasi-crystal fiber (PQF), an optical fiber with a sixfold symmetric quasi-periodic array of air holes in the cladding region. The supermodes of the PQF are calculated by the finite element method, and the coupling of an in-phase supermode for the quasi-periodic optical fiber is numerically optimized to obtain identical values. The optimization is guaranteed by the selection of appropriate PQF design parameters. The eigenvalue equation associated with a seven-core PQF is derived from a coupled mode equation. We realize mode shaping and provide the far-field distribution mode of PQFs. The results are beneficial for the structural design and uniform distribution of the in-phase supermodes of PQFs.

This 180 μm wide, 3D pattern is produced by laser‐induced immobilization of fluorescent molecules onto a polymeric matrix. On page 3429Aleksandr Ovsianikov, Robert Liska, and co‐workers report a versatile and straightforward photografting method based on photolysis of an aromatic azide via multiphoton absorption. Because multiphoton‐induced reactions occur in a confined area within the laser focal spot, accurate functionalization with high spatial resolution in 3D is possible. The presented results indicate the great potential of the 3D, site‐specific, function‐alization method for applications in microarray‐based proteome analysis, studies of cell–surface interactions, sensing applications, and drug screening.