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1.
ACS Nano ; 2020 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-33180469

RESUMO

The direct growth of vertically oriented graphene (VG) on low-priced, easily accessible soda-lime glass can propel its applications in transparent electrodes and energy-relevant areas. However, graphene deposited at low temperature (∼600 °C) on the catalysis-free insulating substrates usually presents high defect density, poor crystalline quality, and unsatisfactory electrical conductivity. To tackle this issue, we select high borosilicate glass as the growth substrate (softening point ∼850 °C), which can resist higher growth temperature and thus afford higher graphene crystalline quality, by using a radio-frequency plasma-enhanced chemical vapor deposition (rf-PECVD) route. A nitrogen doping strategy is also combined to tailor the carrier concentration through a methane/acetonitrile-precursor-based synthetic strategy. The sheet resistance of as-grown nitrogen-doped (N-doped) VG films on high borosilicate glass can thus be lowered down to ∼2.3 kΩ·sq-1 at a transmittance of 88%, less than half of the methane-precursor-based PECVD product. Significantly, this synthetic route allows the achievement of 30-inch-scale uniform N-doped graphene glass, thus promoting its applications as excellent electrodes in high-performance switchable windows. Additionally, such N-doped VG films were also employed as efficient electrocatalysts for electrocatalytic hydrogen evolution reaction.

2.
ACS Nano ; 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-33169976

RESUMO

Single-crystal perovskites with excellent photophysical properties are considered to be ideal materials for optoelectronic devices, such as lasers, light-emitting diodes and photodetectors. However, the growth of large-scale perovskite single-crystal films (SCFs) with high optical gain by vapor-phase epitaxy remains challenging. Herein, we demonstrated a facile method to fabricate large-scale thin CsPbBr3 SCFs (∼300 nm) on the c-plane sapphire substrate. High temperature is found to be the key parameter to control low reactant concentration and sufficient surface diffusion length for the growth of continuous CsPbBr3 SCFs. Through the comprehensive study of the carrier dynamics, we clarify that the trapped-related exciton recombination has the main effect under low carrier density, while the recombination of excitons and free carriers coexist until free carriers plays the dominate role with increasing carrier density. Furthermore, an extremely low-threshold (∼8 µJ cm-2) amplified spontaneous emission was achieved at room temperature due to the high optical gain up to 1255 cm-1 at a pump power of 20 times threshold (∼20 Pth). A microdisk array was prepared using a focused ion beam etching method, and a single-mode laser was achieved on a 3 µm diameter disk with the threshold of 1.6 µJ cm-2. Our experimental results not only present a versatile method to fabricate large-scale SCFs of CsPbBr3 but also supply an arena to boost the optoelectronic applications of CsPbBr3 with high performance.

3.
Enzyme Microb Technol ; 142: 109680, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33220868

RESUMO

The microbial transglutaminase (mTGase) from Streptomyces mobaraense is widely used in the food industry. However, recombinant production of mTGase is challenging because the mTGase is synthesized as an inactive zymogen, and needs to be activated by proteolytic processing. In this study, self-cleaving intein Ssp DnaB was applied to activate the mTGase in Corynebacterium glutamicum. Premature cleavage of intein Ssp DnaB also occurred, but instead of suppressing premature cleavage, this phenomenon was used to produce active mTGase in C. glutamicum. Both SDS-PAGE analysis and mTGase activity assays indicated that the premature cleavage of intein Ssp DnaB activated the mTGase intracellularly in C. glutamicum. The subsequent N-terminal amino acid sequencing and site-directed mutagenesis studies further showed that the premature cleavage activated the mTGase intracellularly, in a highly specific manner. Moreover, the growth performance of C. glutamicum was not noticeably affected by the intracellular expression of active mTGase. Finally, the mTGase was produced in a 2 L bioreactor, with activity up to 49 U/mL, the highest intracellular mTGase activity ever reported. Using premature cleavage of intein Ssp DnaB to activate mTGase in C. glutamicum, we produced high levels of intracellular active mTGase. Moreover, this approach did not require any further processing steps, such as protease treatment or lengthy incubation, greatly simplifying the production of active mTGase. This efficient and simple approach has great potential for the large-scale industrial production of active mTGase.

4.
Medicine (Baltimore) ; 99(44): e23026, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-33126389

RESUMO

RATIONALE: The ubiquinol-cytochrome c reductase synthesis-like (BCS1L) gene is located on chromosome 2 (2q35) and encodes an ATPase that is associated with various cellular activities and is embedded in the mitochondrial inner membrane; this ATPase is presumed to facilitate the insertion of the Rieske Fe/S protein into precursors of Complex III (CIII) during the assembly of the respiratory chain. We report the first case of a compound heterozygous mutation in the BCS1L gene in China. PATIENT CONCERNS: A 7-month-old girl presented with a 3-month history of psychomotor developmental retardation and a 1-month history of epilepsy combined with parallel psychomotor developmental deterioration. The clinical manifestations in the patient included psychomotor developmental retardation, infantile spasms, pili torti, tubulopathy, hepatic pathologies and lactic acidosis. DIAGNOSIS: Combined with her clinical presentation, the patient was diagnosed with CIII deficiency and Björnstad syndrome caused by a novel mutation in the BCS1L gene after molecular biological examination. Whole exome sequencing revealed a compound heterozygous mutation with a missense mutation (c.548G > A/p. R183H) inherited from her mother and an insertion mutation (c.1061_1062insCTA/p. G354delinsGY) inherited from her father. INTERVENTIONS: Before admission, the patient had received oral topiramate for 1 month. After admission, additional intravenous arginine hydrochloride was administered for five days in the acute metabolic disorder phase, and persistent cocktail therapy was introduced, including coenzyme Q10 (20 mg/d), carnitine (1 g/d) and vitamins (vitamin B1, vitamin B2, vitamin B6, and vitamin C). OUTCOMES: The spasm seizures were decreased by 50% after 2 weeks of treatment. The blood ammonia, myocardial enzyme and urine glucose levels declined to normal levels. At a 1-month follow-up, the patient improved clinically with a decrease in spasm seizures of 75%, stronger sucking and more voluntary activities. However, she still had mild lactic acidosis and mild hepatic damage. LESSONS: We reported the first patient with CIII deficiency and Björnstad syndrome in China and identified 1 novel mutation (C.1061_1062insCTA and P. G354delinsGY) in the BCS1L gene. This finding expands the BCS1L gene mutation profile and will be beneficial for genetic diagnosis.


Assuntos
Complexo III da Cadeia de Transporte de Elétrons/genética , Predisposição Genética para Doença , Doenças do Cabelo/genética , Perda Auditiva Neurossensorial/genética , Doenças Mitocondriais/congênito , Feminino , Humanos , Lactente , Doenças Mitocondriais/genética , Mutação , Linhagem
5.
Biomater Sci ; 8(22): 6301-6308, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-33020778

RESUMO

Endo/lysosome entrapment is the key barrier for gene delivery using synthetic polycations. Although the introduction of a membrane-lytic peptide into polycations could facilitate efficient endo/lysosome release and improve gene delivery efficiency, it is always accompanied by serious safety concerns. In this work, the widely used polycations, poly(2-dimethylaminoethyl methacrylate (PDMAEMA), poly(l-lysine) (PLL) and polyethylenimine (PEI), are modified with a pH-sensitive peptide (C6M3) with selective lytic activity to produce three functional polycations to address the issue of endo/lysosome entrapment and facilitate efficient gene transfer. Hemolysis study shows that the functionalized polycations show good biocompatibility toward red blood cells at neutral pH, and exhibit potent membrane lysis activity under acidic conditions, which are both on-demand for the ideal gene carriers. In vitro transfection studies demonstrate that the peptide modified polycations mediate promising gene delivery efficiency with the luciferase plasmid and the green fluorescence protein plasmid in HeLa cells compared to the parent polycations. Owing to the facile preparation and selective lysis activity of the C6M3 modified polycations, these smart gene vectors may be good candidates for the transfer of various nucleic acids and further clinical gene therapy.

6.
Nanotechnology ; 2020 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-33113522

RESUMO

Two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) are promising platforms for developing next-generation electronic and optoelectronic devices due to their unique properties. To achieve this, the growth of large single-crystal TMDs is a critical issue. Unravelling the factors affecting the nucleation and domain orientation should hold fundamental significance. Herein, we design the chemical vapor deposition (CVD) growth of monolayer MoS2triangles on Au(111) and Au(100) facets, for exploring the substrate facet effects on the domain orientations. According to multi-scale characterizations, we find that, the obtained triangular MoS2domains present two preferential orientations on the six-fold symmetric Au(111) facet, whereas four predominant orientations on the four-fold symmetric Au(100) facet. Using on-site scanning tunneling microscopy (STM), we further reveal the preferred alignments of monolayer MoS2triangles along the close-packed directions of both Au(111) and Au(100) facets. Moreover, bunched substrate steps are also found to form along the close-packed directions of the crystal facets, which guides the preferential nucleation of monolayer MoS2along the step edges. This work should hereby deepen the understanding of the substrate facet/step effect on the nucleation and orientation of monolayer MoS2domains, thus providing fundamental insights into the controllable syntheses of large single-crystal TMD monolayers.

7.
Artigo em Inglês | MEDLINE | ID: mdl-32986410

RESUMO

The development of adhesives with superior optical and mechanical performance, solvent resistance, and reworkability is gaining increasing attention in recent years. However, traditional materials do not possess reprocessability and healing characteristics for sustainable development. Here, a superior dynamic polythiourethane (PTU) adhesive with high reprocessability was developed by introducing covalent adaptable networks (CANs). Specifically, dynamic thiocarbamate bonds (TCB) were used to prepare PTU CANs, which showed dramatically enhanced malleability and recyclability. The Young's modulus of the material was 2.0 GPa and the tensile strength was 62.7 MPa. The reprocessing temperature of CANs was reduced to 80 °C while more than 90% of their mechanical properties were retained, even after being reprocessed several times. Moreover, the highly transparent and water-resistant PTU CANs featured an excellent bonding property and reworkability for various materials including glass, with a lap shear strength of 2.9 MPa, metal (5.1 MPa), and wood (6.3 MPa), compared with commercially available adhesives. Additionally, carbon fiber-reinforced composites constructed with PTU CANs were capable of being fully recycled and reused. Importantly, laminated glass with a toughened PTU-PU elastomer interface exhibited an outstanding impact fatigue-resistance behavior, sustaining thousands of impacts. These features demonstrate that PTU CANs show great potential as sustainable materials.

8.
ACS Nano ; 2020 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-32790282

RESUMO

We propose a technique of Raman spectroscopy to characterize the excitonic nature and to evaluate the relative contribution of the two kinds of electron/exciton-phonon interactions that are observed in two-dimensional transition-metal dichalcogenides (TMDCs). In the TMDCs, the electron/exciton-phonon interactions mainly originate from the deformation potential (DP) or the Fröhlich interaction (FI) which give the mutually different Raman tensors. Using a circularly polarized light, the relative proportion of the DP and the FI can be defined by the ratio of helicity-polarized intensity that is observed by MoS2. By this analysis, we show that the excitonic FI interaction gradually increases with decreasing temperature, contributes equally to DP at ∼230 K, and dominates at lower temperatures. The excitonic effect in the Raman spectra is confirmed by modulating the dielectric environment for the exciton and by changing the laser power.

9.
Adv Sci (Weinh) ; 7(16): 2001080, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32832362

RESUMO

Substitutional doping of layered transition metal dichalcogenides (TMDs) has been proved to be an effective route to alter their intrinsic properties and achieve tunable bandgap, electrical conductivity and magnetism, thus greatly broadening their applications. However, achieving valid substitutional doping of TMDs remains a great challenge to date. Herein, a distinctive molten-salt-assisted chemical vapor deposition (MACVD) method is developed to match the volatilization of the dopants perfectly with the growth process of monolayer MoS2, realizing the substitutional doping of transition metal Fe, Co, and Mn. This doping strategy effectively alters the electronic structure and phononic properties of the pristine MoS2. In addition, a temperature-dependent Raman spectrum is employed to explore the effect of dopants on the lattice dynamics and first-order temperature coefficient of monolayer MoS2, and this doping effect is illustrated in depth combined with the theoretical calculation. This work provides an intriguing and powerful doping strategy for TMDs through employing molten salt in the CVD system, paving the way for exploring new properties of 2D TMDs and extending their applications into spintronics, catalytic chemistry and photoelectric devices.

10.
Int J Med Sci ; 17(12): 1683-1691, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32714071

RESUMO

The filamentous actin (F-actin) cytoskeleton is progressively damaged after status epilepticus (SE), which is related to delayed neuronal death, aberrant recurrent circuits and epileptogenesis. Glucocorticoids regulate dendritic spine remodeling by acting on glucocorticoid receptors and the dynamics of the F-actin cytoskeleton. Our previous study showed that administration of dexamethasone (DEX) in the latent period of the pilocarpine epileptic model reduces damage to the hippocampal filamentous actin cytoskeleton and the loss of hippocampal neurons and aids in maintaining the synaptic structures, but it is not sufficient to stop epileptogenesis. In this work, we focused on the role of glucocorticoids in regulating the hippocampal F-actin cytoskeleton during SE. We examined the abundance of synaptic F-actin, analyzed the hippocampal F-actin/G-actin (F/G) ratio and pCofilin, and evaluated the number of hippocampal neurons and pre/postsynaptic markers in pilocarpine-induced status epilepticus mice with or without administration of dexamethasone (DEX). We found that the latency of Stage 3 seizures increased, the mortality decreased, the damage to the synaptic F-actin cytoskeleton in the hippocampal subfields was significantly attenuated, and a greater number of postsynaptic structures were retained in the hippocampal subfields after treatment with DEX. These results indicate that treatment with dexamethasone stabilizes the synaptic F-actin cytoskeleton and reduces the damage to the brain due to SE. This approach is expected to be beneficial in alleviating delayed neuron damage and the process of epileptogenesis.

11.
ACS Appl Mater Interfaces ; 12(30): 34161-34169, 2020 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-32631044

RESUMO

Development of a physical barrier with mechanical properties similar to human smooth muscle and an on-demand degradation profile is crucial for the clinical prevention of postoperative adhesion. Herein, a series of supramolecular hydrogels (PMI hydrogels) composed of poly(ethylene glycol) (PEG), methylenediphenyl 4, 4-diisocyanate (MDI), and imidazolidinyl urea (IU, hydrogen bonding reinforced factor) with biodegradability and high toughness are reported to serve as physical barriers for abdominal adhesion prevention. The tensile fracture strength and strain of the PMI hydrogels could be adjusted in the ranges of 0.6-2.3 MPa and 100-440%, respectively, and their Young's moduli (0.2-1.6 MPa) are close to that of human soft tissues like smooth muscle and skin tissue as well as they have outstanding shape memory properties. The PMI hydrogels show good cell and tissue biocompatibility, and the in vivo retention time is in accord with the needs for the postoperative antiadhesion physical barriers. Through an abdominal defect model on mice, this study shows that the PMI hydrogel can completely prevent tissue adhesion compared to the commercialized Seprafilm with high safety. Owing to the promising mechanical properties and good biocompatibility, the PMI hydrogels may be extended for various biomedical applications and the development of advanced flexible electronic devices.

12.
Dalton Trans ; 2020 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-32648888

RESUMO

Chemical vapor deposition (CVD) route has emerged as an effective method for the successful synthesis of two-dimensional (2D) materials with satisfactory crystal quality, especially for the synthesis of wafer-scale, uniform thickness or large domain size single-crystal transition metal chalcogenides (TMCs). To achieve this, the salt-assisted CVD strategy has been proved to be powerful to reduce the high melting point of the metal related precursor, decrease the nucleation density and increase the reaction rate on the solid template. However, the specific roles of alkali metals and halide components still remain unclear. Herein, the functions of salts in the growth of TMCs have been discussed by summarizing some recent achievements in salt-assisted synthesis results, wherein salts are mainly introduced as additives in metal precursors to achieve the wafer-scale uniform growth of monolayer and thickness-tunable multi-layered TMCs, and for serving as 3D templates (especially NaCl) to realize the scalable production of TMCs. Moreover, the existing challenges and viable future directions are also proposed for in-depth understanding of salt-assisted C4VD methods and for exploring more efficient CVD strategies.

13.
Artigo em Inglês | MEDLINE | ID: mdl-32677819

RESUMO

Developing recyclable, self-healable and highly malleable thermosets is one of the keys to relieve environmental pollution and meet our increasing demand for "greener" materials. Hindered urea bonds (HUBs) have been successfully incorporated in preparing dynamic covalent networks with those desirable properties. However, one key drawback is the low thermal stability and poor mechanical performance of previously reported systems. In this work, we demonstrated that the incorporation of aromatic-moiety-containing diamine based HUBs can greatly improve the thermal and mechanical performance of the PUUs while still maintaining the desirable recycling, self-healing and reprocessing properties. Studies on model compounds revealed the origin of the thermal stability and demonstrated the dynamic property. The aromatic-containing diamine based HUBs were then used to prepare a series of catalyst-free poly(urethane-urea)s (PUUs) with improved thermal and mechanical properties. The dynamic HUBs significantly reduced the relaxation time scale and allowed the PUU networks to be recycled multiple times. The healed and recycled PUUs regained most of the mechanical strength and integrity of the original material. Therefore, this unique and simple approach is expected to open up new avenues to design PUUs with optimal performance for various applications.

14.
Opt Lett ; 45(14): 4072-4075, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32667357

RESUMO

In this work, we reported the design and fabrication of a compact and scalable metamaterial longpass filter with an ultrasmall footprint of 5.1µm×5.1µm. In the stopband, light transmission can be blocked and reflected with ∼25dB attenuation. In the passband, light can pass through with a low insertion loss around -0.28dB. The transition band can be redshifted or blueshifted by scaling up or down the filter block; i.e., scaling down 1% can produce a transition band blueshift of 11.4 nm. The power roll-off can be enhanced by cascading multiple filter blocks, i.e., 1.34 dB/nm by cascading three filters. These results demonstrate the great potential of the metamaterial-based waveguide devices for scalable photonic filtering applications.

15.
Hum Mol Genet ; 29(15): 2523-2534, 2020 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-32628254

RESUMO

A common feature of autoimmune diseases, including systemic lupus erythematosus (SLE), is an increased prevalence in women. However, the molecular basis for sex disparity in SLE remains poorly understood. To examine the role of X-linked transcription in SLE adaptive immune cells, we performed RNA-seq in T cell and B cell subsets from either healthy donors or patients with SLE. Analyses of allelic expression (AE) profiles identified a pattern of increased allelic imbalance across the entire X chromosome in SLE lymphocytes. X-linked genes exhibiting AE in SLE had an extensive overlap with genes known to escape X chromosome inactivation (XCI). XIST RNA was overexpressed in SLE patients. Differential XIST expression correlated with AE profiles more positively at X-linked genes than the genome-wide background. Analysis of three independent RNA-seq data verified the XIST-associated skewed AE on X chromosome in SLE. Integrative analyses of DNA methylation profiles showed an increased variability of DNA methylation levels at these AE-related X-linked genes. In cultured lymphoblastic cells, knockdown of XIST specifically altered allelic imbalance patterns between X chromosomes. Our study provides genetic evidence that upregulation of XIST accompanied with more skewed allelic expression on X chromosome is associated with the pathogenesis of SLE and may provide mechanistic insights into the increased incidence of SLE in females.

16.
Hear Res ; 395: 108023, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32702613

RESUMO

The hippocampus is a brain structure well known for its importance to spatial learning and memory. As such it is assumed to use multisensory integration in order to generate mathematical maps of the spatial environment. Auditory inputs to the hippocampus have been described to a limited extent. Although it has been demonstrated that natural auditory stimulation can evoke local field potentials (LFPs) and single neuron responses in the hippocampus, and that noise trauma and tinnitus can cause maladaptive hippocampal plasticity, to the best of our knowledge no one has selectively, electrically stimulated the cochlea and recorded electrophysiological responses in the hippocampus. Here, we used unilateral electrical cochlear stimulation in rats while recording LFPs in the hippocampus bilaterally, with a multi-electrode array. We observed triphasic LFP responses bilaterally from unilateral stimulation, but with larger amplitudes on the contralateral side, especially for Phase 1 and 3 of the LFP, for which the latencies were also longer. The latencies under urethane anaesthesia were consistent with auditory information from the cochlea travelling across approximately 6-7 synapses. These data demonstrate that the cochlea contributes a powerful auditory input to the hippocampus, which is also lateralized, and may have implications for spatial cognition in cochlear implant patients.

17.
Environ Pollut ; 266(Pt 1): 115187, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32668359

RESUMO

The choice of sediment quality assessment methodologies can strongly influence assessment outcomes and management decisions for contaminated sites. While in situ (field) methods may potentially provide greater realism, high costs and/or complex logistics often prevent their use and assessment must rely on laboratory-based methods. In this study, we utilised static-renewal and flow-through ecotoxicology tests in parallel on sediments with a wide range of properties and varying types and concentrations of contaminants. The prediction of chronic effects to amphipod reproduction was explored using multiple linear regression (MLR). The study confirmed the considerable over-estimation of the risk of toxicity of contaminated sediments in field locations when assessments rely on the results of laboratory-based static and static-renewal tests. Improved prediction of toxicity risks was achieved using a combination of contaminant exposure measures from sediment and overlying water. Existing sediment and water quality guideline values (GVs) were effective for predicting risks posed by sediments containing mixtures of common metal and organic contaminants. For 17 sediments with paired data sets from static-renewal and flow-through tests, the best prediction of toxicity to reproduction was achieved using a 2-parameter MLR that included hazard quotients for sediment contaminants and toxic units for dissolved metals (r2 = 0.892). The inclusion of particle size, organic carbon and acid-volatile sulfide did not improve toxicity predictions, despite these parameters being recognised as modifying contaminant bioavailability. The use of dilute-acid-extractable metal concentrations in place total recoverable metal concentrations did not improve the predictions. The study also confirmed that sediments existing within the estuarine and marine bays of Sydney Harbour pose significant risks of adverse effects to benthic organisms.


Assuntos
Anfípodes , Poluentes Químicos da Água/análise , Animais , Sedimentos Geológicos , Metais/análise , Água
18.
Nano Lett ; 2020 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-32492341

RESUMO

Ultrasonic transducers with large output power have attracted extensive attentions due to their widespread applications in sonar, acoustic levitation, ultrasonic focusing, and so forth. However, the traditional transducer has almost no heat-dissipation capability itself, strictly relying on the assistant coolant system. Introducing high-performance heat-dissipation component is thus highly necessary. Herein, an embedded porcelain radiator component was designed by combining the excellent thermal conductivity of vertically oriented graphene (VG) with the outstanding heat-dissipation characteristics of thermosensitive ceramics, and a new-type transducer with an embedded VG/ceramic-hybrid radiator was constructed to show high heat-dissipation efficiency (up to ∼5 °C/min). Remarkably, prominent heat-dissipation effectiveness (temperature decline of ∼12 °C), enhanced amplitude and vibration uniformity were also achieved for the new-type transducer along with stabilized operating states. This research should pave ways for extending the applications of VG/ceramic hybrids to heat-dissipation scenarios and provide newfangled thoughts for the performance upgrade of multitudinous high-power devices.

19.
Phys Rev Lett ; 124(21): 213901, 2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32530673

RESUMO

Multiplication and division of the orbital angular momentum (OAM) of light are important functions in the exploitation of the OAM mode space for such purposes as high-dimensional quantum information encoding and mode division multiplexed optical communications. These operations are possible with optical transformations that reshape optical wave fronts according to azimuthal scaling. However, schemes proposed thus far have been limited to OAM multiplication by integer factors and require complex beam-copying or multitransformation diffraction stages; a result of the limited phase excursion 2πℓ around the annulus of an OAM state exp(iℓθ). Based on the key idea that the phase excursion along spirals in the transverse plane of a vortex is theoretically unlimited, we propose and experimentally demonstrate a simple yet effective scheme using an azimuth-scaling spiral transformation that can accomplish both OAM multiplication and division by arbitrary rational factors in a single stage.

20.
Artigo em Inglês | MEDLINE | ID: mdl-32597173

RESUMO

Ensuring material performance reliability and lifetime is crucial for practical operations. Small cracks on the material surface are often detrimental to its safe operation. This study describes the development of a hydrogen bond-rich puncture-resistant polyurethane elastomer with supertoughness. The as-prepared polyurethane transparent films feature high tensile break strength (57.4 MPa) and great toughness (228 MJ m-3). Additionally, a facile, low-cost, crack self-diagnostic approach through photoluminescence using a small luminous pen is reported. The materials efficiently achieved self-healing at 90 °C after the crack formation. The change of fluorescence intensity on the crack can be used to track the self-healing process. Therefore, this work provides a guideline for the material design of supertough, puncture-resistant, transparent, and healable elastomers and a crack self-diagnosis and healing approach.

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