Short-wavelength-infrared upconversion edge enhancement imaging based on a Laguerre-Gaussian composite vortex filter.

Edge-enhanced imaging by spiral phase contrast has proven instrumental in revealing phase or amplitude gradients of an object, with notable applications spanning feature extraction, target recognition, and biomedical fields. However, systems deploying spiral phase plates encounter limitations in phase mask modulation, hindering the characterization of the modulation function during image reconstruction. To address this need, we propose and demonstrate an innovative nonlinear reconstruction method using a Laguerre-Gaussian composite vortex filter, which modulates the spectrum of the target. The involved nonlinear process spectrally transforms the incident short-wavelength-infrared (SWIR) signal from 1550 to 864 nm, subsequently captured by a silicon charge-coupled device. Compared with conventional schemes, our novel filtering method effectively suppresses the diffraction noise, significantly enhancing image contrast and resolution. By loading specific phase holograms on the spatial light modulator, bright-field imaging, isotropic, amplitude-controlled anisotropic, and directional second-order edge-enhanced imaging are realized. Anticipated applications for the proposed SWIR edge-enhanced imaging system encompass domains such as artificial intelligence recognition, deep tissue medical diagnostics, and non-destructive defect inspection. These applications underscore the valuable potential of our cutting-edge methodology in furthering both scientific exploration and practical implementations.

Ketamine induces insomnia-like symptom of zebrafish at environmentally relevant concentrations by mediating GABAergic synapse.

Although the stimulative effects on the normal behaviors of fish posed by ketamine (KET) were well-studied, the adverse effects on the behavioral functions induced by KET at nighttime were unknown. Here, we used zebrafish larvae as a model exposed to KET (10, 50, 100, and 250 ng/L) at environmental levels for 21 days. The behavioral functions at nighttime, morphological changes during exposure stage, and alterations on the associated genes transcriptional levels of fish were determined. The difficultly initiating sleep was found in the fish exposed to KET, while the sleep duration of the animals was at the normal levels in exposure groups. The significant suppressions of the developmentally relevant genes, including bmp2, bmp4, and pth2ra were consistent with the developmental abnormalities of fish found in exposure groups. Moreover, the expression of γ-aminobutyric acid (GABA) receptor increased and melatonin (MTN) receptor decreased while the levels of GABA and MTN remained unchanged after exposure, by gene expression analysis and molecular docking. In addition, the transcriptional expression of apoptotic genes, including tp53, aifm1, and casp6, was significantly upregulated by KET. After a 7-day recovery, the insomnia-like behaviors (shorter sleep duration) were observed in zebrafish from the 250 ng/L-KET group. Accordingly, the adverse outcome pathway framework of KET was constructed by prognostic assessment of zebrafish larvae. This study suggested that the adverse outcomes of KET on the sleep health of organisms at environmentally relevant concentrations should be concerned.

Unraveling potential mechanism of different metal ions effect on anammox through big data analysis, molecular docking and molecular dynamics simulation.

Heavy metals (HMs) have been widely reported to pose an adverse effect on anaerobic ammonia oxidation (anammox) bacteria, yet the underlying mechanisms remain unclear. This study provides new insights into the potential mechanisms of interaction between HMs and functional enzymes through big date analysis, molecular docking and molecular dynamics simulation. The statistical analysis indicated that 10 mg/L Cu(II) and Cd(II) reduced nitrogen removal rate (NRR) by 85% and 43%, while 5 mg/L Fe(II) enhanced NRR by 29%. Additionally, the results of molecular simulations provided a microscopic interpretation for these macroscopic data. Molecular docking revealed that Hg(II) formed a distinctive binding site on ferritin, while other HMs resided at iron oxidation sites. Furthermore, HMs exhibited distinct binding sites on hydrazine dehydrogenase. Concurrently, the molecular dynamics simulation results further substantiated their capacity to form complexes. Cu(II) displayed the strongest binding affinity with ferritin for -1576 ± 79 kJ/mol in binding free energy calculation. Moreover, Cd(II) bound to ferritin and HDH for -1052.67 ± 58.49 kJ/mol, -290.02 ± 49.68 kJ/mol, respectively. This research addressed a crucial knowledge gap, shedding light on potential applications for remediating heavy metal-laden industrial wastewater.

Generation of arbitrary complex fields with high efficiency and high fidelity by cascaded phase-only modulation method.

Independent or joint control over the amplitude and phase of the complex field by phase-only modulation element is crucial in numerous applications. Existing modulation methods can realize high levels of accuracy but are accompanied by noticeable losses in light-usage efficiency. Here a cascaded modulation method is proposed for the generation of arbitrary complex fields with high efficiency and high fidelity. This approach is based on a gradient descent optimization algorithm that minimizes a customized cost function. The major advantage of our approach over existing modulation methods is that the efficiency is significantly enhanced while ensuring high modulation accuracy. For the generation of Laguerre-Gaussian mode (LG01), with similar high accuracy, the efficiency by our approach can reach 79.5%, which is enhanced by 192% compared with the theoretical maximum efficiency of 41.5% [Opt. Express25, 11692 (2017)10.1364/OE.25.011692]. Furthermore, the efficiency of existing modulation methods deteriorates rapidly as the target field turns more intricate, whereas in our approach it maintains at a relatively high level. The field generation fidelity and energy efficiency of the proposed cascaded modulation method are compared with that of several different single-pass modulation methods in generating a series of typical Hermite-Gaussian and Laguerre-Gaussian modes and an amplitude-only "OSA" pattern. Our proposed method features both high efficiency and high accuracy in the simulation and experiment, which may be of growing interest to applications such as optical manipulation or quantum communication.

[68Ga]Ga-FAPI PET for the evaluation of digestive system tumors: systematic review and meta-analysis.

PURPOSE: Digestive system tumors are a group of tumors with high incidence in the world nowadays. The assessment of digestive system tumor metastasis by conventional imaging seems to be unsatisfactory. [68Ga]Ga-FAPI, which has emerged in recent years, seems to be able to evaluate digestive system tumor metastasis. We aimed to summarize the current evidence of [68Ga]Ga-FAPI PET/CT or PET/MR for the assessment of primary tumors, lymph node metastases, and distant metastases in digestive system tumors. Besides, we also aimed to perform a meta-analysis of the sensitivity of [68Ga]Ga-FAPI PET diagnosis to discriminate between digestive system tumors, primary lesions, and non-primary lesions (lymph node metastases and distant metastases). MATERIALS AND METHODS: PubMed, MEDLINE and Cochrane Library databases were searched from the beginning of the database build to August 12, 2022. All studies undergoing [68Ga]Ga-FAPI PET for the evaluation of digestive tumors were included in the screening and review. Screening and full text review was performed by 3 investigators and data extraction was performed by 2 investigators. Risk of bias was examined with the QUADAS-2 criteria. Diagnostic test meta-analysis was performed with a random-effects model. RESULTS: A total of 541 studies were retrieved. Finally, 22 studies were selected for the systematic review and 18 studies were included in the meta-analysis. In the 18 publications, a total of 524 patients with digestive system tumors, 459 primary tumor lesions of digestive system tumors, and 1921 metastatic lesions of digestive system tumors were included in the meta-analysis. Based on patients, the sensitivity of [68Ga]Ga-FAPI PET for the diagnosis of digestive system tumors was 0.98 (95% CI: 0.94-0.99). Based on lesions, the sensitivity of [68Ga]Ga-FAPI PET for the diagnostic evaluation of primary tumor lesions of the digestive system was 0.97 (95% CI: 0.93-0.99); the sensitivity of [68Ga]Ga-FAPI PET for the diagnostic evaluation of non-primary lesions (lymph node metastases and distant metastases) of the digestive system tumors was 0.94 (95% CI: 0.79-0.99). CONCLUSION: [68Ga]Ga-FAPI PET has high accuracy and its sensitivity is at a high level for the diagnostic evaluation of digestive system tumors. Clinicians, nuclear medicine physicians, and radiologists may consider using [68Ga]Ga-FAPI PET/CT or PET/MR in the evaluation of primary tumors, lymph node metastases, and distant metastases in digestive system tumors.

Photo-Induced C-H Methylation Reactions.

Direct C-H methylation is a highly valuable approach for introducing methyl groups into organic molecules, particularly in pharmaceutical chemistry. Among the various methodologies available, photo-induced methylation stands out as an exceptional choice due to its mild reaction conditions, energy efficiency, and compatibility with functional groups. This article offers a comprehensive review of photochemical strategies employed for the direct and selective methylation of C(sp3 )-H, C(sp2 )-H, and C(sp)-H bonds in various organic molecules. The discussed methodologies encompass transition-metal-based photocatalysis, organophotocatalysis, as well as other metal-free approaches, including electron donor-acceptor (EDA)-enabled transformations. Importantly, a wide range of easily accessible agents such as tert-butyl peroxide, methanol, DMSO, methyl tert-butyl ether, TsOMe, N-(acetoxy)phthalimide, acetic acid, methyl halides, and even methane can serve as effective methylating reagents for modifying diverse targets. These advancements in photochemical C-H methylation are anticipated to drive further progress in the fields of organic synthesis, photocatalysis, and pharmaceutical development, opening up exciting avenues for creating novel organic molecules and discovering new drug compounds.

Backward THz Emission from Two-Color Laser Field-Induced Air Plasma Filament.

Two-color laser field-induced plasma filaments are efficient broadband terahertz (THz) sources with intense THz waves emitted mainly in the forward direction, and they have been investigated intensively. However, investigations on the backward emission from such THz sources are rather rare. In this paper, we theoretically and experimentally investigate the backward THz wave radiation from a two-color laser field-induced plasma filament. In theory, a linear dipole array model predicts that the proportion of the backward emitted THz wave decreases with the length of the plasma filament. In our experiment, we obtain the typical waveform and spectrum of the backward THz radiation from a plasma with a length of about 5 mm. The dependence of the peak THz electric field on the pump laser pulse energy indicates that the THz generation processes of the forward and backward THz waves are essentially the same. As the laser pulse energy changes, there is a peak timing shift in the THz waveform, implying a plasma position change caused by the nonlinear-focusing effect. Our demonstration may find applications in THz imaging and remote sensing. This work also contributes to a better understanding of the THz emission process from two-color laser-induced plasma filaments.

Scaling of the terahertz emission from liquid water lines by plasma reshaping.

Liquids are proposed to be promising terahertz (THz) sources. However, the detected THz electric field is limited by the collection efficiency and saturation effect. A simplified simulation based on the interference of ponderomotive-force-induced dipoles indicates that, by reshaping the plasma, the THz radiation is concentrated in the collection direction. Experimentally, by using a cylindrical lens pair to form a line-shaped plasma in transverse section, the THz radiation is redirected, and the pump energy dependence follows a quadratic trend, indicating that the saturation effect is significantly weakened. As a result, the detected THz energy is enhanced by a factor of ∼5. This demonstration provides a simple but effective way of further scaling detectable THz signals from liquids.

Coherent injection photocurrent in bismuth sulfide film induced by one-plus-two photon absorption quantum interference.

Quantum interference (QuI) effect is a powerful method to generate and control the ultrafast photocurrent in semiconductors. We utilize two-color pulsed light excitation in bismuth sulfide (Bi2S3) film to induce the photocurrent through the QuI effect. Experimentally, the photocurrent is indirectly monitored using a standard terahertz (THz) time-domain spectroscopic system. Due to the QuI, an asymmetric photon injection occurs in Bi2S3 film, resulting in coherent injection current and subsequently THz wave generation. Our results on the pump pulse energy dependence of the THz electric field suggests that the THz wave generation process follows the third-order nonlinear optical process.

The effects of incorporation of the counterparts and mimics of L-lysine on the antimicrobial activity, hemolytic activity, cytotoxicity and tryptic stability of antimicrobial peptide polybia-MPII.

Due to the limited effects of conventional antibiotics on the increasing emergence of drug-resistant bacteria and fungi, novel antimicrobial agents were urgently needed to alleviate this phenomenon. Nowadays, antimicrobial peptides are believed to be a promising candidate for a new generation of antimicrobial drugs. Antimicrobial peptide polybia-MPII (MPII) was first isolated from the venom of the social wasp Polybia paulista with a broad spectrum of antimicrobial activity. In the present study, the counterparts and mimics of cationic amino acids of Lys, such as Arg, His, Orn, Dab and Dap were employed to substitute Lys in the sequence of MPII. The effects of the incorporation of these amino acids on its antimicrobial activity, hemolytic activity, cytotoxicity, enzyme stability and therapeutic potential were explored. Our results showed that although the incorporation of Arg could improve its antimicrobial activity, there is no improvement in enzyme stability. The incorporation of His makes MPII exert its antimicrobial activity in a pH-dependent manner. Notably, incorporating Dap could effectively decrease its hemolytic activity and cytotoxicity and enhance its enzyme stability against trypsin. In conclusion, this study would provide an effective strategy to improve the bioavailability and metabolic stability of AMPs while decrease their hemolytic activity and cytotoxicity.

Liriogerphines A-D, a Class of Sesquiterpene-Alkaloid Hybrids from the Rare Chinese Tulip Tree Plant.

Liriogerphines A-D (1-4, respectively), an unprecedented class of hybrids of germacranolide-type sesquiterpenoids and aporphine-type alkaloids, were isolated from the rare medicinal plant Liriodendron chinense. Their structures were elucidated by comprehensive spectroscopic analyses combined with electronic circular dichroism calculations and X-ray crystallographic data. Biosynthetically, an aza-Michael addition reaction is proposed to be involved in the assemblies of this class of hybrids. Compound 4 exhibited cytotoxicity against leukemia cells via inducing apoptosis and inhibiting Bcl-2 expression.

Optimization of brightness in a Nd:YAG laser by maximizing the single-mode power factor with an intra-cavity spatial light modulator.

We report a simple and effective approach for designing resonators with high brightness and high mode discrimination based on optimizing the single-mode power factor of the fundamental mode, which represents the total power extracted by the fundamental mode from the gain medium. By optimizing the single-mode power factor of the fundamental mode, the cavity can be designed to operate in mono-mode, increasing mode purity and improving brightness significantly. Our method is verified on a digital laser with a spatial light modulator as the rear mirror, and the loaded phase profile is acquired by a simulated annealing algorithm. As a result, the optimized resonator with a Fresnel number of 7.2 operates in a single fundamental mode, and the brightness of the output beam yields 240% and 276% improvement, compared with conventional plane-plane and plane-concave resonators, respectively. This approach is ready to be applied to more sophisticated mode selection and may serve as a general method for designing cavities with high efficiency and high brightness.

The evolutionary trends of health inequality among elderly Chinese people and influencing factors of these trends from 2005 to 2017.

Reducing health inequality and ensuring national health equity have become issues of great concern to all countries in the world. This paper based on the ordered Probit model and concentrated index decomposition method, analysed the influencing factors and evolution trend of health inequality among the elderly with high age in China from 2005 to 2017. The study found that in 2005-2017, the self-rated health distribution of the elderly with high age in China showed an obvious inverted "U" shape, with the proportion of general and relatively healthy being the largest, while the proportion of unhealthy and very healthy was lower. Lifestyle, family income, and age were the main important factors to expand health inequality. Therefore, encouraging the elderly with high age to develop good living habits and narrowing the income gap of the elderly are conducive to solving the health inequality of the elderly with high age and achieving the goals of active ageing and healthy ageing.

Systematic investigation of terahertz wave generation from liquid water lines.

Understanding the process of terahertz (THz) wave generation from liquid water is crucial for further developing liquid THz sources. We present a systematic investigation of THz wave generated from laser-irradiated water lines. We show that water line in the diameter range of 0.1-0.2 mm generates the strongest THz wave, and THz frequency red shift is observed when diameter of the water line increases. The pump pulse energy dependence is decoupled from self-focusing effect by compensating the focal point displacement. As the pump pulse energy increases, saturation effect in THz peak electric field is observed, which can be mainly attributed to the intensity clamping effect inside the plasma and have never been reported previously, using water line or water film as the THz source. The proposed mechanism for saturation is supported by an independent measurement of laser pulse spectrum broadening. This work may help to further understand the laser-liquid interaction in THz generation process.

The introduction of L-phenylalanine into antimicrobial peptide protonectin enhances the selective antibacterial activity of its derivative phe-Prt against Gram-positive bacteria.

Protonectin was a typical amphiphilic antimicrobial peptide with potent antimicrobial activity against Gram-positive and Gram-negative bacteria. In the present study, when its eleventh amino acid in the sequence was substituted by phenylalanine, the analog named phe-Prt showed potent antimicrobial activity against Gram-positive bacteria, but no antimicrobial activity against Gram-negative bacteria, indicating a significant selectivity between Gram-positive bacteria and Gram-negative bacteria. However, when Gram-negative bacteria were incubated with EDTA, the bacteria were susceptible to phe-Prt. Next, the binding effect of phe-Prt with LPS was determined. Our result showed that LPS could hamper the bactericidal activity of phe-Prt against Gram-positive bacteria. The result of zeta potential assay further confirmed the binding effect of phe-Prt with LPS for it could neutralize the surface charge of E. coli and LPS. Then, the effect of phe-Prt on the integrity of outer membrane of Gram-negative bacteria was determined. Our results showed that phe-Prt had a much weaker disturbance to the outer membrane of Gram-negative bacteria than the parent peptide protonectin. In summary, the introduction of L-phenylalanine into the sequence of antimicrobial peptide protonectin made phe-Prt show significant selectivity against Gram-positive bacteria, which could partly be attributed to the delay effect of LPS for phe-Prt to access to cell membrane. Although further study is still needed to clarify the exact mechanism of selectivity, the present study provided a strategy to develop antimicrobial peptides with selectivity toward Gram-positive and Gram-negative bacteria.

Enhanced terahertz emission from mushroom-shaped InAs nanowire network induced by linear and nonlinear optical effects.

The development of powerful terahertz (THz) emitters is the cornerstone for future THz applications, such as communication, medical biology, non-destructive inspection, and scientific research. Here, we report the THz emission properties and mechanisms of mushroom-shaped InAs nanowire (NW) network using linearly polarized laser excitation. By investigating the dependence of THz signal to the incidence pump light properties (e.g. incident angle, direction, fluence, and polarization angle), we conclude that the THz wave emission from the InAs NW network is induced by the combination of linear and nonlinear optical effects. The former is a transient photocurrent accelerated by the photo-Dember field, while the latter is related to the resonant optical rectification effect. Moreover, thep-polarized THz wave emission component is governed by the linear optical effect with a proportion of ∼85% and the nonlinear optical effect of ∼15%. In comparison, thes-polarized THz wave emission component is mainly decided by the nonlinear optical effect. The THz emission is speculated to be enhanced by the localized surface plasmon resonance absorption of the In droplets on top of the NWs. This work verifies the nonlinear optical mechanism in the THz generation of semiconductor NWs and provides an enlightening reference for the structural design of powerful and flexible THz surface and interface emitters in transmission geometry.

Multiple action mechanism and in vivo antimicrobial efficacy of antimicrobial peptide Jelleine-I.

With the extensive use of antibiotics in medicine, agriculture and food chemistry, the emergence of multi-drug resistant bacteria become more and more frequent and posed great threats to human health and life. So novel antimicrobial agents were urgently needed to defend the resistant bacteria. Jelleine-I was a small antimicrobial peptide (AMP) with eight amino acids in its sequence. It was believed to be an ideal template for developing antimicrobial agents. In the present study, the possible action mode against both gram-negative bacteria and gram-positive bacteria and in vivo antimicrobial activity was explored. Our results showed that Jelleine-I exhibits its antimicrobial activity mainly by disrupting the integrity of the cell membrane, which would not be affected by the conventional resistant mechanism. It also aims at some intracellular targets such as genomic DNA to inhibit the growth of microbes. In addition, the result of in vivo antimicrobial activity experiment showed that Jelleine-I performed a good therapeutic effect toward the mice with Escherichia coli infected peritonitis. Notably, Jelleine-I has negligible cytotoxicity toward the tested mammalian cells, indicating excellent cell selectivity between prokaryotic cells and eurkayotic cells. In summary, our results showed that Jelleine-I would be a potential candidate to be developed as a novel antimicrobial agent.

Forrestiacids†A and†B, Pentaterpene Inhibitors of ACL and Lipogenesis: Extending the Limits of Computational NMR Methods in the Structure Assignment of Complex Natural Products.

Forrestiacids A (1) and B (2) are a novel class of [4+2] type pentaterpenoids derived from a rearranged lanostane moiety (dienophile) and an abietane unit (diene). These unprecedented molecules were isolated using guidance by molecular ion networking (MoIN) from Pseudotsuga forrestii, an endangered member of the Asian Douglas Fir Family. The intermolecular hetero-Diels-Alder adducts feature an unusual bicyclo[2.2.2]octene ring system. Their structures were elucidated by spectroscopic analysis, GIAO NMR calculations and DP4+ probability analyses, electronic circular dichroism calculations, and X-ray diffraction analysis. This unique addition to the pentaterpene family represents the largest and the most complex molecule successfully assigned using computational approaches to predict accurately chemical shift values. Compounds 1 and 2 exhibited potent inhibitory activities (IC50 s <5 µM) of ATP-citrate lyase (ACL), a new drug target for the treatment of glycolipid metabolic disorders including hyperlipidemia. Validating this activity 1 effectively attenuated the de novo lipogenesis in HepG2 cells. These findings provide a new chemical class for developing potential therapeutic agents for ACL-related diseases with strong links to traditional medicines.

Simultaneous reconstruction of phase and amplitude for wavefront measurements based on nonlinear optimization algorithms.

The non-perfect determined amplitude distribution in the pupil would affect the convergence speed and accuracy of phase retrieval method, which depends on the amplitude of fields to reconstruct the phase. In this paper, we propose two kinds of phase retrieval methods based on hybrid point-polynomial and point-by-point nonlinear optimization algorithms to reconstruct simultaneously the amplitude and phase of the wavefront. Intensity quantized errors are avoided by using modified first derivatives. For simple and general wavefront testing, the accuracy and robustness of proposed algorithms are verified both numerically and experimentally.

Optical steering of electron beam in laser plasma accelerators.

Using a Dazzler system and tilting a compressor grating, we provide an effective way of using the laser group delay dispersion to continuously steer the electron beam accelerated by an asymmetric laser wakefield. The deviation angle of the electron beam was the same as that of the angularly chirped laser pulse from its initial optical axis, which is determined by the laser pulse-front-tilt (PFT). This method can be utilized to continuously control over the pointing direction of electron bunches to the requisite trajectories, especially for practical applications in highly sensitive alignment devices such as electron-positron colliders or undulators. Additionally, we investigate the effect of PFT on the properties of the electron beam.