Xiaogang Liu

Bio: Xiaogang Liu is an academic researcher from National University of Singapore. The author has contributed to research in topics: Medicine & Photon upconversion. The author has an hindex of 94, co-authored 425 publications receiving 41825 citations. Previous affiliations of Xiaogang Liu include Heilongjiang University & Massachusetts Institute of Technology.

Laser-Splashed Plasmonic Nanocrater for Ratiometric Upconversion Regulation and Encryption

Abstract: DOI: 10.1002/adom.201900610 encoding strategies, spectral encryption based on spatial patterning of luminescent materials possessing distinct emission features is widely implemented.[15–17] With innate virtues such as superior photostability, narrow emission bandwidths, and long luminescence lifetime, lanthanidedoped upconversion nanoparticles (UCNPs) have been extensively applied in many emerging areas such as 3D displays,[18,19] biomedical imaging,[20–22] solar cells,[23–25] lasing,[26,27] and especially data encryption.[28–30] Notably, the high designability in emission bands, strong resistance to photobleaching, and low autofluorescence interference make UCNPs a promising alternative to conventional fluorophores (such as organic dyes and quantum dots) in highcapacity and long-term optical encoding applications.[31–33] Over the past few years, UCNP-mediated data encryption through multicolor barcoding,[6] lifetime tuning,[34–36] and phase angle hybridization[37] has been successfully demonstrated. Nevertheless, these encoding strategies rely on a different set of UCNPs to achieve distinct emission features in confined temporal or spatial regions, which would inevitably introduce the difficulty to the design of data multiplexing and sample synthesis. Plasmonic nanomaterials, working as optical antennas, can enormously intensify their adjacent local fields to tailor light–matter interactions on demand through tuning the geometry, equilibrium configuration, or choice of nanoantenna materials.[38] Especially those noble metal nanostructures (such as Au and Ag) featuring surface plasmon resonances, have proven effective in tuning the emission properties of UCNPs. By varying the size or aspect ratio of these plasmonic nanostructures, their resonance bands can be precisely tuned to match either the absorption or emission bands of adjacent UCNPs. Therefore, the excitation rate or radiative emission rate of UCNPs could be programmably enlarged to achieve luminescence enhancement for the whole spectrum or any specific emission band.[39–48] The integration of plasmonic nanostructures with UCNPs opens new encoding strategies in addition to enhanced upconversion luminescence (UCL) intensities.[49,50] However, the inherent high electrical conductivity of metallic materials can suppress the quantum yields of emission when the UCNPs are in contact with the metallic surface.[51,52] Upconversion nanoparticles (UCNPs) with exceptional optical properties have emerged as a new paradigm for data encryption through multicolor coding, lifetime tuning, and excitation light phasing. However, in addition to low internal quantum efficiency, the utility of UCNPs for data encryption is largely hampered by the requirement of multiple sets of UCNPs of complex compositions with specifically tailored optical properties. Herein, it is found that metal–insulator–metal (MIM) configurations are capable of regulating upconversion emission of UCNPs through programmable geometry-dependent plasmonic features of laser-splashed submicron cavities. Furthermore, a ratiometric encryption strategy by regulating the ratio of dualband emission of a single set of UCNPs of fixed composition placed within the plasmonic MIM configuration is demonstrated. High-throughput encryption and decryption through the luminescence ratiometric strategy can be achieved in a facile laser writing fashion with upscalability and sub-micrometer-scale precision. This demonstration opens a new route to luminescence modulation with large encoding capacity and underpins potential applications of UCNPs in multiplexed data storage and information encryption.

Absorbant superhydrophobic materials, and methods of preparation and use thereof

Abstract: The present invention relates to coated, absorbent, freestanding assemblies comprising inorganic nanowires, articles of manufacture comprising the same, processes of producing the same and methods of use thereof. The assemblies of this invention are useful in various applications, including removal of organics or hydrophobic materials, and waterproofing applications.

An Edaravone-Guided Design of a Rhodamine-Based Turn-on Fluorescent Probe for Detecting Hydroxyl Radicals in Living Systems

Abstract: The hydroxyl radical (·OH), one of the reactive oxygen species (ROS) in biosystems, is found to be involved in many physiological and pathological processes. However, specifically detecting endogenous ·OH remains an outstanding challenge owing to the high reactivity and short lifetime of this radical. Herein, inspired by the scavenging mechanism of a neuroprotective drug edaravone toward ·OH, we developed a new ·OH-specific fluorescent probe RH-EDA. RH-EDA is a hybrid of rhodamine and edaravone and exploits a ·OH-specific 3-methyl-pyrazolone moiety to control its fluorescence behavior. RH-EDA itself is almost nonfluorescent in physiological conditions, which was attributed to the formation of a twisted intramolecular charge transfer (TICT) state upon photoexcitation and the acylation of its rhodamine nitrogen at the 3' position. However, upon a treatment with ·OH, its edaravone subunit was converted to the corresponding 2-oxo-3-(phenylhydrazono)-butanoic acid (OPB) derivative (to afford RH-OPB), thus leading to a significant fluorescence increase (ca. 195-fold). RH-EDA shows a high sensitivity and selectivity to ·OH without interference from other ROS. RH-EDA has been utilized for imaging endogenous ·OH production in living cells and zebrafishes under different stimuli. Moreover, RH-EDA allows a high-contrast discrimination of cancer cells from normal ones by monitoring their different ·OH levels upon stimulation with β-Lapachone (β-Lap), an effective ROS-generating anticancer therapeutic agent. The present study provides a promising methodology for the construction of probes through a drug-guided approach.

High Piezoelectric Performance and Phase Transition in Stressed Lead‐Free (1 – x)(K, Na)(Sb, Nb)O3‐x(Bi, Na, K)ZrO3 Thin Films

Abstract: Although high performance piezoelectric properties have been reported in (K, Na)NbO3-based bulk ceramics by constructing morphotropic phase boundary (MPB) with complex compositions, it is still challenging to achieve excellent piezoelectric properties in thin films with the same MPB compositions due to the serious volatile loss of the alkali constituents. Moreover, the stress due to substrate constraint also changes the film's crystal structure and shifts the film's MPB. Here this study demonstrates the highest ever reported effective piezoelectric strain coefficient d33 of 184.0 pm V−1 and voltage coefficient g33 of 39.4 mm V N−1 from macroscale characterization in a solution-derived lead-free piezoelectric thin film with a composition of (1 – x)(K, Na)(Sb, Nb)O3-x(Bi, Na, K)ZrO3 (KNSN-BNKZx, 0.01 ≤ x ≤ 0.07). With the effective suppression of volatile compositional loss by selecting appropriate combinational chemical agents in the precursor solution, phase transitions from orthorhombic, rhombohedral to tetragonal are observed experimentally and further analyzed theoretically with first principle simulation of the KNSN-BNKZx films, and the obtained coexistence of rhombohedral–tetragonal phase at x = 0.05 contributes to the outstanding piezoelectric performance in the tensile stressed films. The results demonstrate a valuable strategy for realizing high-performance piezoelectric properties in thin films with volatile and complex MPB compositions under stress condition.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Room-temperature ultraviolet nanowire nanolasers

Abstract: Room-temperature ultraviolet lasing in semiconductor nanowire arrays has been demonstrated The self-organized, oriented zinc oxide nanowires grown on sapphire substrates were synthesized with a simple vapor transport and condensation process These wide band-gap semiconductor nanowires form natural laser cavities with diameters varying from 20 to 150 nanometers and lengths up to 10 micrometers Under optical excitation, surface-emitting lasing action was observed at 385 nanometers, with an emission linewidth less than 03 nanometer The chemical flexibility and the one-dimensionality of the nanowires make them ideal miniaturized laser light sources These short-wavelength nanolasers could have myriad applications, including optical computing, information storage, and microanalysis

Structural absorption by barbule microstructures of super black bird of paradise feathers

Abstract: Many studies have shown how pigments and internal nanostructures generate color in nature. External surface structures can also influence appearance, such as by causing multiple scattering of light (structural absorption) to produce a velvety, super black appearance. Here we show that feathers from five species of birds of paradise (Aves: Paradisaeidae) structurally absorb incident light to produce extremely low-reflectance, super black plumages. Directional reflectance of these feathers (0.05-0.31%) approaches that of man-made ultra-absorbent materials. SEM, nano-CT, and ray-tracing simulations show that super black feathers have titled arrays of highly modified barbules, which cause more multiple scattering, resulting in more structural absorption, than normal black feathers. Super black feathers have an extreme directional reflectance bias and appear darkest when viewed from the distal direction. We hypothesize that structurally absorbing, super black plumage evolved through sensory bias to enhance the perceived brilliance of adjacent color patches during courtship display.