Antibacterial Activity of Plants in Cirsium: A Comprehensive Review.

As ethnic medicine, the whole grass of plants in Cirsium was used as antimicrobial. This review focuses on the antimicrobial activity of plants in Cirsium, including antimicrobial components, against different types of microbes and bacteriostatic mechanism. The results showed that the main antimicrobial activity components in Cirsium plants were flavonoids, triterpenoids and phenolic acids, and the antimicrobial ability varied according to the species and the content of chemicals. Among them, phenolic acids showed a strong antibacterial ability against Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterococcus faecium. The antibacterial mechanisms include: (1) damaging the cell membrane, cell walls, mitochondria and nucleus of bacteria; (2) inhibiting the synthesis of proteins and nucleic acids; (3) suppressing the synthesis of enzymes for tricarboxylic acid cycle pathways and glycolysis, and then killing the bacteria via inhibition of energy production. Totally, most research results on antimicrobial activity of Cirsium plants are reported based on in vitro assays. The evidence from clinical data and comprehensive evaluation are needed.

Supramolecular Room Temperature Phosphorescent Materials Based on Cucurbit[8]uril for Dual Detection of Dodine.

In recent years, host-guest interactions of macrocycles have attracted much attention as an emerging method for enhancing the intersystem crossing of pure organic room-temperature phosphorescence. In this work, we utilize cucurbit[8]uril (Q[8]) to specifically recognize synthetic bromophenyl pyridine derivatives (BPCOOH) to construct a highly stable charge-transfer dimer, where the bromophenyl pyridine moiety of BPCOOH is encapsulated by Q[8] in a 1:2 host/guest ratio. The assemblies exhibit specific recognition and detection properties for dodine on both fluorescence and phosphorescence spectra. Subsequently, the solid films were prepared by introducing carboxymethylcellulose sodium into the assemblies, which greatly enhanced its RTP performance by increasing the noncovalent bonding interactions, enabling the visualization of high-strength RTP and quantitative testing of the solid state. Finally, this material was used for the application of portable indicator papers to achieve rapid and visualized detection of dodine in daily life, which provides more possibilities for the potential applications of cucurbit[n]uril-based room-temperature phosphorescence material.

Subspecies Taxonomy and Inter-Population Divergences of the Critically Endangered Yellow-Breasted Bunting: Evidence from Song Variations.

The critically endangered Yellow-breasted Bunting has undergone population collapse globally because of illegal hunting and habitat deterioration. It was listed as critically endangered (CR) by the International Union for Conservation of Nature (IUCN) in 2017 and designated a Class I (highest level) national conservation bird species in China in 2021. Birdsong in the breeding season is the main communicative signal under sexual selection, and song variations have long been considered critical evidence of divergence among subspecies or populations. We compared the songs of 89 males from 18 populations to test subspecies taxonomy. We found that songs of the Yellow-breasted Bunting Emberiza aureola are subspecies specific and that three subspecies can be clearly discriminated by song divergences. Moreover, an analysis of multiple vocal traits supports the claim that insulana is distinct from aureola and ornata. Finally, at the geographic population level, populations can be clearly classified in accordance with the three subspecies, although the aureola population in Xinjiang, China is differentiated from other populations of the same subspecies. The results of this study demonstrate that all populations and subspecies are unique and should be protected to maintain intraspecies song diversity. In addition, several specific populations, such as insulana populations in Japan and the Xinjiang, China population of aureola, need to be paid special attention to prevent the extinction of unique or local taxa.

Epitaxial Topological Insulator Bi2Te3 for Fast Visible to Mid-Infrared Heterojunction Photodetector by Graphene As Charge Collection Medium.

Three dimensional topological insulators have a thriving application prospect in broadband photodetectors due to the possessed topological quantum states. Herein, a large area and uniform topological insulator bismuth telluride (Bi2Te3) layer with high crystalline quality is directly epitaxial grown on GaAs(111)B wafer using a molecular beam epitaxy process, ensuring efficient out-of-plane carriers transportation due to reduced interface defects influence. By tiling monolayer graphene (Gr) on the as-prepared Bi2Te3 layer, a Gr/Bi2Te3/GaAs heterojunction array prototype was further fabricated, and our photodetector array exhibited the capability of sensing ultrabroad photodetection wavebands from visible (405 nm) to mid-infrared (4.5 µm) with a high specific detectivity (D*) up to 1012 Jones and a fast response speed at about microseconds at room temperature. The enhanced device performance can be attributed to enhanced light-matter interaction at the high-quality heterointerface of Bi2Te3/GaAs and improved carrier collection efficiency through graphene as a charge collection medium, indicating an application prospect of topological insulator Bi2Te3 for fast-speed broadband photodetection up to a mid-infrared waveband. This work demonstrated the potential of integrated topological quantum materials with a conventional functional substrate to fabricate the next generation of broadband photodetection devices for uncooled focal plane array or infrared communication systems in future.

Study on the interactions between melamine-cored Schiff bases with cucurbit[n]urils of different sizes and its application in detecting silver ions.

Three different complexes, TMeQ[6]-TBT, Q[7]-TBT, and Q[8]-TBT are constructed by three different cucurbiturils and synthesized by guest melamine-cored Schiff bases (TBT) through outer-surface interaction and host-guest interactions. TBT forms a TMeQ[6]-TBT complex with TMeQ[6] through outer-surface interaction, while Q[7]-TBT and Q[8]-TBT form complexes with Q[7,8] through host-guest interactions. Among them, Q[7]-TBT is selected as a UV detector for the detection of silver ions (Ag+). This work makes full use of the characteristics of each cucurbituril and melamine-cored Schiff base to construct a series of complexes and these are applied to metal detection.

[Effects of elevated CO2 concentration on photosynthetic acclimation of winter wheat under drought condition]. / 大气CO2æµ“åº¦å‡é«˜å¯¹å¹²æ—±æ¡ä»¶ä¸‹å†¬å°éº¦å¶ç‰‡å ‰åˆé€‚åº”çš„å½±å“.

Mechanisms underlying leaf photosynthetic acclimation in winter wheat under elevation of CO2 concentration ([CO2]) remain unclear. The aim of the study was to investigate the effects of source-sink variation on photosynthetic acclimation induced by drought under elevated [CO2]. A winter wheat (Triticum aestivum L. 'Zhengmai 9023') pot experiment was conducted in open top climate chambers with [CO2] of 400µmol·mol-1 or 600 µmol·mol-1 and soil water content at 80%±5% or 55%±5% of field capacity. The parameters of chlorophyll fluorescence, electron transport rate, photosynthetic curve, leaf nitrogen content, and grain yield were measured at the elongation and heading stages. Under drought condition, leaf PSⅡ photochemical efficiency was not affected by elevated [CO2], but the maximum electron transport rate and the ratio of electron partitioned to carboxylation reaction in Calvin cycle was increased at the elongation stage, and thus the Rubisco carboxylation rate and maximum photosynthetic rate were increased. Although the maximum electron transportation rate and partitioning ratio of electron to carboxylation reaction in Calvin cycle remained high at the heading stage, the PSⅡ photochemical efficiency, Rubisco carboxylation rate, and triose phosphate utilization rate were decreased by elevated [CO2], which consequently reduced the maximum photosynthetic rate for plant under drought stress. Under drought condition, elevated [CO2] increased wheat tiller biomass, kernel number, and kernel weight per ear, but decreased infertile kernel number, resulting in an overall increase in grain weight. In conclusion, the elevated [CO2]-induced increase in wheat grain yield per tiller under drought condition was mainly caused by enhanced photosynthetic performance at the elongation stage. The photosynthetic acclimation in source leaves during the heading stage under elevated [CO2] was mainly attributed to the reduction in PSⅡ photochemical efficiency and triose phosphate utilization rate, but not to the maximum electron transportation rate, ratio of electron partitioned to carboxylation in Calvin cycle or sink leaf strength.

Discovery of 2-(Ortho-Substituted Benzyl)-Indole Derivatives as Potent and Orally Bioavailable RORγ Agonists with Antitumor Activity.

RORγ is a dual-functional drug target, which involves not only induction of inflammation but also promotion of cancer immunity. The development of agonists of RORγ promoting Th17 cell differentiation could provide a novel mechanism of action (MOA) as an immune-activating anticancer agent. Herein, we describe new 2-(ortho-substituted benzyl)-indole derivatives as RORγ agonists by scaffold hopping based on clinical RORγ antagonist VTP-43742. Interestingly, subtle structural differences of the compounds led to the opposite biological MOA. After rational optimization for structure-activity relationship and pharmacokinetic profile, we identified a potent RORγ agonist compound 17 that was able to induce the production of IL-17 and IFNγ in tumor tissues and elicit antitumor efficacy in MC38 syngeneic mouse colorectal tumor model. This is the first comprehensive work to demonstrate the in vivo antitumor efficacy of an RORγ agonist.

A silicon-based PbSe quantum dot near-infrared photodetector with spectral selectivity.

Traditional photodetectors usually respond to photons larger than the bandgap of a photosensitive material. In contrast to traditional photodetectors for broad-spectrum detection, the currently reported PbS/PMMA/PbSe CQD silicon-based photodetectors can detect spectrally selective light sources. This is attributed to two layers with specific functions, a filter layer on top and a photosensitive layer in contact with the silicon channel. Each of the target sources of the device has a selectivity factor of more than 10 against non-target sources. The s-PD (selective photodetector) has three significant advantages: the ability to tunably adjust the detectable spectral range by easily adjusting the size of QDs. The second is using a new architecture to achieve a high-performance selective photodetector, and finally, the ease-of-integration with silicon. The above features enable the device to meet the needs of particular fields such as secure communication, surveillance, and infrared imaging.

Broadband THz Absorption of Microbolometer Array Integrated with Split-Ring Resonators.

In this paper, a periodic structure based on metallic split-ring resonators is integrated into micro-bridge structures of THz microbolometer array to achieve high THz wave absorption in a wide frequency range. With a small unit size of 35 µm × 35 µm, the effect of split-ring structure on THz wave absorption characteristics of the multilayer structure array is studied to manipulate the resonance absorption frequencies. The absorption bandwidth is effectively increased by integrating a combined structure of split-ring and metallic disk. Broadband THz absorption is formed by coupling the absorption peaks of different structures. The periodic structure of dual-ring combined with a metallic disk provides a broadband THz wave absorption in the range of 4-7 THz. The highest absorption in the band reaches 90% and the lowest absorption is higher than 40%. The designed structure is process-compatible and easy to implement for small-pixel THz microbolometers with high absorption in a wide spectrum range. The research provides a scheme for broadband THz sensing and real-time imaging at room temperature.

Photonic nanojets with ultralong working distance and narrowed beam waist by immersed engineered dielectric hemisphere.

Engineered spherical micro-lens can manipulate light at sub-wavelength scale and emerges as a promising candidate to extend the focal length and narrow the focal spot size. Here, we report the generation of photonic nanojets (PNJs) with an ultralong working distance and narrowed beam waist by an immersed engineered hemisphere. Simulations show that a two-layer hemisphere of 4.5 µm radius exhibits a PNJ with the working distance of 9.6 µm, full width at half maximum of 287 nm, and length of 23.37 λ, under illumination of a plane wave with a 365 nm wavelength. A geometrical optics analysis indicated that the formed PNJ behind the immersed two-layer hemisphere results from the convergence of light of the outer-hemisphere fringe area, which refracts into and passes through the outer hemisphere and then directly leaves the outer-hemisphere flat surface. Thus the embedded hemisphere is comparable to an immersed focusing lens with high numerical aperture, which can promise both long working distance and narrowed beam waist. This is further demonstrated with the corresponding embedded-engineered single-layer hemisphere, whose spherical face is partly cut parallel to the hemispherical flat surface. In addition, the hemisphere is compatible with adjacent laser wavelengths. Finally, a spot size smaller than 0.5 λ is demonstrated in the lithography simulation. Due to these hemispheres low cost, they have potential in far-field lithography for pattern arrays with line width less than 0.5 λ.

Light-modulated vertical heterojunction phototransistors with distinct logical photocurrents.

The intriguing carrier dynamics in graphene heterojunctions have stimulated great interest in modulating the optoelectronic features to realize high-performance photodetectors. However, for most phototransistors, the photoresponse characteristics are modulated with an electrical gate or a static field. In this paper, we demonstrate a graphene/C60/pentacene vertical phototransistor to tune both the photoresponse time and photocurrent based on light modulation. By exploiting the power-dependent multiple states of the photocurrent, remarkable logical photocurrent switching under infrared light modulation occurs in a thick C60 layer (11 nm) device, which implies competition of the photogenerated carriers between graphene/C60 and C60/pentacene. Meanwhile, we observe a complete positive-negative alternating process under continuous 405 nm irradiation. Furthermore, infrared light modulation of a thin C60 (5 nm) device results in a photoresponsivity improvement from 3425 A/W up to 7673 A/W, and we clearly probe the primary reason for the distinct modulation results between the 5 and 11 nm C60 devices. In addition, the tuneable bandwidth of the infrared response from 10 to 3 × 103 Hz under visible light modulation is explored. Such distinct types of optical modulation phenomena and logical photocurrent inversion characteristics pave the way for future tuneable logical photocurrent switching devices and high-performance phototransistors with vertical graphene heterojunction structures.

Silicon-based PbS-CQDs infrared photodetector with high sensitivity and fast response.

Silicon-based photodetectors as the main force in visible and near-infrared detection devices have been deeply embedded in modern technology and human society, but due to the characteristics of silicon itself, its response wavelength is generally less than 1100 nm. It is an interesting study to combine the state-of-art silicon processing with emerging infrared-sensitive Lead sulfide colloidal quantum dots (PbS-CQDs) to produce a photodetector that can detect infrared light. Here, we demonstrated a silicon-compatible photodetector that could be integrated on-chip, and also sensitive to infrared light which is owing to a PbS-CQDs absorption layer with tunable bandgap. The device exhibit extremely high gain which reaches maximum detectivity [Formula: see text], fast response 211/558 µs, and extremely high external quantum efficiency [Formula: see text], which is owing to new architecture and reasonable ligand exchange options. The performance of the device originates from the new architecture, that is, using the photovoltaic voltage generated by the surface of PbS-CQDs to change the width of the depletion layer to achieve detection. Besides, the performance improvement of devices comes from the addition of PbS-CQDs (Ethanedithiol treated) layer, which effectively reduces the fall time and makes the device expected to work at higher frequencies. Our work paves the way for the realization of cost-efficient high-performance silicon compatible infrared optoelectronic devices.

High responsivity and fast UV-vis-short-wavelength IR photodetector based on Cd3As2/MoS2 heterojunction.

High responsivity, fast response time, ultra-wide detection spectrum are pursuing goals for state-of-art photodetectors. Cd3As2, as a three-dimensional (3D) Dirac semimetal, has a zero bandgap, high light absorption rate in broad spectral region, and higher mobility than graphene at room temperature. However, photoconductive detectors based Cd3As2 suffer low quantum efficiency due to the absence of high built-in field. Here, a Cd3As2 nanoplate/multilayer MoS2 heterojunction photodetector was fabricated which achieved a quite high responsivity of 2.7 × 103 A W-1 at room temperature. The photodetector exhibits a short response time of in broad spectra region from ultraviolet (365 nm) to short-wavelength-infrared (1550 nm) and reached 65 µs at 650 nm. This work provides a great potential solution for high-performance photodetector and broadband imaging by combining 3D Dirac semi-metal materials with semiconductor materials.

Two-Sided Topological Architecture on a Monolithic Flexible Substrate for Ultrasensitive Strain Sensors.

Flexible ultrasensitive strain sensors are highly desirable in view of their widespread applications in wearable electronics, health monitoring systems, and smart robots, where subtle strain detection is required. However, traditional fabrication of such sensors was done to prepare sensitive layers on bare or single-sided structural substrates, leading to limited sensitivity. Herein, a stretchable resistive-type strain sensor was demonstrated by self-assembling conductive networks onto a monolithic polydimethylsiloxane substrate with a two-sided topological design, for example, a sinusoid/auxetic binary architecture. The sensitivity of the obtained sensor was greatly improved by 22-fold as compared to the traditional counterpart with a bare substrate. The remarkably good agreement between the experimental results and finite element analysis predictions confirmed that the superior sensitivity is a synergistic effect of local strain enhancement derived from the topological structure on the foreside and an additional strain concentration and a reduced Poisson's ratio from the auxetic arrays on the backside. Furthermore, this sensor can withstand an extreme mechanical force (>750 N) because of the shear stiffening characteristic of the auxetic structure. Benefiting from the characteristics of ultrahigh sensitivity (gauge factor ∼1744 at 5%), low detection limit (<0.05%), and long-term durability (>500 loading cycles), this as-prepared sensor shows promise in practical applications of high-performance wearable electronics.

Polarimetric Three-Dimensional Topological Insulators/Organics Thin Film Heterojunction Photodetectors.

As a state of quantum matter with insulating bulk and gapless surface states, topological insulators (TIs) have huge potential in optoelectronic devices. On the other hand, polarization resolution photoelectric devices based on anisotropic materials have overwhelming advantages in practical applications. In this work, the 3D TIs Bi2Te3/organics thin film heterojunction polarimetric photodetectors with high anisotropic mobility ratio, fast response time, high responsivity, and EQE in broadband spectra are presented. At first, the maximum anisotropic mobility ratio of the Bi2Te3/organics thin film can reach 2.56, which proves that Bi2Te3 can serve as a sensitive material for manufacturing polarization photoelectric devices. Moreover, it is found that the device can exhibit a broad bandwidth and ultrahigh response photocurrent from visible to middle wave infrared spectra (405-3500 nm). The highest responsivity (Ri) of optimized devices can reach up to 23.54 AW-1; surprisingly, the Ri of the device can still reach 1.93 AW-1 at 3500 nm. In addition, the ultrahigh external quantum efficiency is 4534% with a fast response time (1.42 ms). Excellent properties mentioned above indicate that TIs/organics heterojunction devices are suitable for manufacturing high-performance photoelectric devices in infrared region.

Ultraviolet to Long-Wave Infrared Photodetectors Based on a Three-Dimensional Dirac Semimetal/Organic Thin Film Heterojunction.

In this work, high-performance ultraviolet to long-wave infrared (UV-LIR) devices based on an N-type three-dimensional (3D) Dirac semimetal Cd3As2 and P-type organic (small molecules and polymers) heterojunction are prepared. Primarily, the photodetector shows a broadband photoresponse from 365 to 10600 nm. The optimized device responsivity is 729 mA/W, along with a fast response time of 282 µs and a high on-off ratio of 6268, which are 2 orders of magnitude higher than those previously reported for a 3D Dirac semimetal-based device. In the LIR region (10600 nm), the responsivity and on-off ratio can reach 81.3 mA/W and 100, respectively. In addition, the time-resolved femtosecond pump detection technology is used to reveal the relaxation time of Cd3As2/organic thin films (4.30 ps), indicating that Cd3As2/organic thin films have great potential for the manufacture of fast IR devices. These results demonstrate that the 3D Dirac semimetal/organic thin film heterojunction photodetectors will be a feasible solution for high-speed and broadband photodetectors in large-array imaging.

Graphene/Organic Semiconductor Heterojunction Phototransistors with Broadband and Bi-directional Photoresponse.

A graphene-semiconductor heterojunction is very attractive for realizing highly sensitive phototransistors due to the strong absorption of the semiconductor layer and the fast charge transport in the graphene. However, the photoresponse is usually limited to a narrow spectral range determined by the bandgap of the semiconductor. Here, an organic heterojunction (C60 /pentacene) is incorporated on graphene to realize a broadband (405-1550 nm) phototransistor with a high gain of 5.2 × 105 and a response time down to 275 µs. The visible and near-infrared parts of the photoresponsivity (9127 A W-1 @650 nm and 1800 A W-1 @808 nm) come from the absorption of the organic layer and the graphene, respectively. For the first time, a bi-directional (positive and negative) photoresponse is demonstrated at different wavelengths, due to the opposite charge transfer direction of the photoexcited carriers enforced by the unique band alignment. Such tunability will enable new functionalities such as large-scale real-time optical image and infrared focal plane array detection in the future.

Optical Properties and Sensing Performance of Au/SiO2 Triangles Arrays on Reflection Au Layer.

In order to enhance the refractive index sensing performance of simple particle arrays, a structure, consisting of Au/SiO2 triangle arrays layers and reflection Au substrate, with increasing size and lengthening tips of triangles, is studied. The triangle arrays are modeled after an experimentally realizable "imprint" of microsphere lithography. Numerical calculation was carried out to study its optical properties and spectral sensitivity. The calculation results show that a large local enhancement of electric field (61 times) and simultaneously high absorption is due to combination of the resonance absorption of Au triangle disks, plasmonic couplings between the Au triangle disks and the Au film, and the high-density packing of triangle disks. The absorption peaks were not detuned when the gap between neighboring tips of the triangles varied from 10 to 50 nm. When the thickness of SiO2 layer increased from 10 to 50 nm, the absorption peak shifted to longer wavelengths and the amplitude rises quickly signaling the dominance of the gap mode resonance between the two Au layers. As the thickness of the top Au layer varies from 10 to 50 nm, the absorption peak is also red shifted and the peak amplitude increases. The full width at half maximum of the peaks for high absorption (> 90%) is about 5 nm. When fixing the gap, the thicknesses of Au/SiO2 triangle layer, and increasing the surrounding refractive index from 1.33 to 1.36, the absorption peaks shifted quickly, with a refractive index sensitivity and figure of merit as high as 660 nm per refractive index unit and 132, respectively. Such arrays can be easily fabricated by using microsphere array as projection masks and find application in refractive index monitoring of liquid and identification of gas and liquid phases.

Frequency Modulation and Absorption Improvement of THz Micro-bolometer with Micro-bridge Structure by Spiral-Type Antennas.

Antenna-coupled micro-bridge structure is proven to be a good solution to extend infrared micro-bolometer technology for THz application. Spiral-type antennas are proposed in 25 µm × 25 µm micro-bridge structure with a single separate linear antenna, two separate linear antennas, or two connected linear antennas on the bridge legs, in addition to traditional spiral-type antenna on the support layer. The effects of structural parameters of each antenna on THz absorption of micro-bridge structure are discussed for optimized absorption of 2.52 THz wave radiated by far infrared CO2 lasers. The design of spiral-type antenna with two separate linear antennas for wide absorption peak and spiral-type antenna with two connected linear antennas for relatively stable absorption are good candidates for high absorption at low absorption frequency with a rotation angle of 360*n (n = 1.6). Spiral-type antenna with extended legs also provides a highly integrated micro-bridge structure with fast response and a highly compatible, process-simplified way to realize the structure. This research demonstrates the design of several spiral-type antenna-coupled micro-bridge structures and provides preferred schemes for potential device applications in room temperature sensing and real-time imaging.

Spiral Antenna-Coupled Microbridge Structures for THz Application.

Bolometer sensor is a good candidate for THz imaging due to its compact system, low cost, and wideband operation. Based on infrared microbolometer structures, two kinds of antenna-coupled microbridge structures are proposed with different spiral antennas: spiral antenna on support layer and spiral antenna with extended legs. Aiming at applications in detection and imaging, simulations are carried out mainly for optimized absorption at 2.52 THz, which is the radiation frequency of far-infrared CO2 lasers. The effects of rotation angle, line width, and spacing of the spiral antenna on THz wave absorption of microbridge structures are discussed. Spiral antenna, with extended legs, is a good solution for high absorption rate at low absorption frequency and can be used as electrode lead simultaneously for simplified manufacturing process. A spiral antenna-coupled microbridge structure with an absorption rate of more than 75% at 2.52 THz is achieved by optimizing the structure parameters. This research demonstrates the use of different spiral antennas for enhanced and tunable THz absorption of microbridge structures and provides an effective way to fabricate THz microbolometer detectors with great potential in the application of real-time THz imaging.