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The rational integration of chemotherapy and hydroxyl radical (·OH)-mediated chemodynamic therapy (CDT) via functional metal-organic frameworks (MOF) carriers has great potential in cancer therapy. In this work, aminotriazole (3-AT) doped polyhedral metal organic frameworks (denoted as MAF) were prepared by template ligand replacement, where CDT was initiated by Cu2+/Cu+ modulated Fenton reaction and enhanced by effectively regulating the catalase activity with 3-AT. However, a rod-like Cu-MOF with 3-AT served as a ligand was obtained by the hydrothermal method without using template. In contrast to Cu-MOF, pH-responsive MAF was chosen as the carrier for targeted drug delivery due to its higher drug load of 17.6% and relatively uniform size, where doxorubicin (DOX) as a model drug was loaded in its cavity and hyaluronic acid (HA) was coated on its surface via electrostatic interactions (denoted as HA-MAF@DOX). In vitro experiments demonstrated that HA-MAF@DOX had high transport efficiency of DOX, effective regulation of catalase (CAT) activity and enhanced cytotoxicity to HepG2 cells. This work is the first use of enzyme inhibitors as ligands to construct functional MOFs via template ligand replacement for effective regulating enzyme activity, mediating intracellular redox homeostasis and enhancing CDT efficacy, which provides a feasible strategy for the construction the functional MOFs in cancer therapy.

Multidimensional imaging of transient events has proven pivotal in unveiling many fundamental mechanisms in physics, chemistry, and biology. In particular, real-time imaging modalities with ultrahigh temporal resolutions are required for capturing ultrashort events on picosecond timescales. Despite recent approaches witnessing a dramatic boost in high-speed photography, current single-shot ultrafast imaging schemes operate only at conventional optical wavelengths, being suitable solely within an optically-transparent framework. Here, leveraging on the unique penetration capability of terahertz radiation, we demonstrate a single-shot ultrafast terahertz photography system that can capture multiple frames of a complex ultrafast scene in non-transparent media with sub-picosecond temporal resolution. By multiplexing an optical probe beam in both the time and spatial-frequency domains, we encode the terahertz-captured three-dimensional dynamics into distinct spatial-frequency regions of a superimposed optical image, which is then computationally decoded and reconstructed. Our approach opens up the investigation of non-repeatable or destructive events that occur in optically-opaque scenarios.

A novel core-shell metal organic framework (MOF), Cu-MOF@SMON/DOX-HA, was fabricated using 3-amino-1,2,4-triazole (3-AT) and organosilicon for combined chemo-chemodynamic therapy with high drug-loading capacity, pH/GSH dual-responsiveness, and good biocompatibility. The Cu-MOF@SMON/DOX-HA could not only generate reactive oxygen species, but also effectively consume glutathione (GSH) to induce cell ferroptosis. This work involves the modification of organosilicon on the surface of MOFs, which possess good performance in high drug-loading ability and pH/GSH dual-responsive degradation for combined chemo-chemodynamic therapy.

Aiming at the deformation and failure of roadway surrounding rock and its control problems under goaf in upper and lower coal seam mining of Buertai Coal Mine, the distribution characteristics of surrounding rock stress in different mining stages of goaf were analyzed, the evolution law of plastic zone of roadway surrounding rock under goaf was analyzed, and the failure mechanism of roadway surrounding rock was revealed by theoretical calculation and numerical simulation.The results show that: the principal stress of the mining roadway under the goaf is smaller than that of the original rock stress. The plastic zone of surrounding rock is small during excavation. Affected by the first mining, the maximum principal stress is 1.24 times of the original rock stress, and the minimum principal stress is 1.49 times of the original rock stress. Affected by the secondary mining, the maximum principal stress is 1.52 times of the original rock stress, and the minimum principal stress is 1.74 times of the original rock stress. In order to control the malignant development of surrounding rock plastic zone, the staged support technology in different mining stages is proposed, and the stress environment of surrounding rock is improved by hydraulic fracturing, so as to reduce the plastic zone of surrounding rock and maintain the safety and stability of surrounding rock.

The presence of a corrosion layer on lead art and archæological objects can severely impede the interpretation of inscriptions, thus hampering our overall understanding of the object and its context. While the oxidation of lead that dominates corrosion may be chemically reversible via reduction, potentially providing some access to inscriptions otherwise obscured by time, corrosion damage is overall neither entirely reversible nor is the reduction process in all cases easy or feasible to carry out. In this study, by taking advantage of the unique penetration ability of terahertz radiation and the abundant frequency bands covered by a single-cycle terahertz pulse, we perform nondestructive terahertz multispectral imaging to look under the corrosion on a sixteenth century lead funerary cross (croix d’absolution) from Remiremont in Lorraine, France. The multispectral images obtained from various terahertz frequency bands are fed into a judiciously designed post-processing chain for image restoration and enhancement, thus allowing us for the first time to read obscured inscriptions that might have otherwise been lost. Our approach, which brings together in a new way the THz properties of the constituent materials and advanced signal- and image-processing techniques, opens up new perspectives for multi-resolution analysis at terahertz frequencies as a technique in archæometry and will ultimately provide unprecedented information for digital acquisition and documentation, character extraction, classification, and recognition in archæological studies.

We demonstrate a new waveguide geometry, namely a four-wire waveguide, which acts as a terahertz polarization-division multiplexer and a novel platform to realize versatile signal-processing functionalities into independent channels over a broadband terahertz frequency range.

Communication links operating at terahertz frequencies are envisioned to provide a revolutionary enhancement of data transmission. As fundamental building blocks, waveguides play an indispensable role in future terahertz networks, not only transporting data streams with unprecedented data rates, but also serving as a versatile platform for signal processing. Among various terahertz waveguides, metal-wire waveguides have attracted particular attention due to their distinct characteristics, such as structural simplicity, broad operating bandwidths, low transmission losses, and low dispersion, in turn making them promising candidates for signal processing. However, because of the tight confinement of modal energy within the wavelength-scale space, manipulating the propagating terahertz signals in-between the metal-wires is challenging. Here, we report the most recent advances in the realization of signal-processing functionalities within metal-wire waveguides. Based on these state-of-the-art methodologies, broadband signal processors that can function as filters, couplers, temporal integrators, as well as multiplexers, have been obtained. We expect this review to inspire new terahertz metal-wire signal processors with high potential for real-time tunability and reconfigurability.

This paper is devoted to reviewing the results achieved so far in the application of the single-pixel imaging technique to terahertz (THz) systems. The use of THz radiation for imaging purposes has been largely explored in the last twenty years, due to the unique capabilities of this kind of radiation in interrogating material properties. However, THz imaging systems are still limited by the long acquisition time required to reconstruct the object image and significant efforts have been recently directed to overcome this drawback. One of the most promising approaches in this sense is the so-called "single-pixel" imaging, which in general enables image reconstruction by patterning the beam probing the object and measuring the total transmission (or reflection) with a single-pixel detector (i.e., with no spatial resolution). The main advantages of such technique are that i) no bulky moving parts are required to raster-scan the object and ii) compressed sensing (CS) algorithms, which allow an appropriate reconstruction of the image with an incomplete set of measurements, can be successfully implemented. Overall, this can result in a reduction of the acquisition time. In this review, we cover the experimental solutions proposed to implement such imaging technique at THz frequencies, as well as some practical uses for typical THz applications.

The combination of chemodynamic therapy (CDT) and chemotherapy is a promising strategy to achieve enhanced anticancer effects. Metal-organic frameworks (MOFs), as multifunctional drug delivery vehicles, have received extensive attention in the biomedical field. Carbohydrate has excellent biocompatibility and targeting ability, which can be used as a targeting ligand due to a specific recognition with glycoprotein receptors that overexpress on cancer cell membranes. Herein, the pH-responsive mannose-modified ferrocene MOFs with rare earth metal were synthesized via coordination-driven self-assembly of 1,1'-Ferrocenedicarboxylic acid and ytterbium chloride. Subsequently, DOX@Fc-MOFs-Mann nanoparticles (NPs) were obtained by loading doxorubicin (DOX) and modifying mannose (Mann), where DOX@Fc-MOFs-Mann NPs were able to precisely target HepG2 cells via mannose receptor and slowly decompose in the acidic environment of tumor to release ferrocene, DOX, and Yb

Waveguides play a pivotal role in the full deployment of terahertz communication systems. Besides signal transporting, innovative terahertz waveguides are required to provide versatile signal-processing functionalities. Despite fundamental components, such as Bragg gratings, have been recently realized, they typically rely on complex hybridization, in turn making it extremely challenging to go beyond the most elementary functions. Here, we propose a universal approach, in which multiscale-structured Bragg gratings can be directly etched on metal-wires. Such an approach, in combination with diverse waveguide designs, allows for the realization of a unique platform with remarkable structural simplicity, yet featuring unprecedented signal-processing capabilities. As an example, we introduce a four-wire waveguide geometry, amenable to support the low-loss and low-dispersion propagation of polarization-division multiplexed terahertz signals. Furthermore, by engraving on the wires judiciously designed Bragg gratings based on multiscale structures, it is possible to independently manipulate two polarization-division multiplexed terahertz signals. This platform opens up new exciting perspectives for exploiting the polarization degree of freedom and ultimately boosting the capacity and spectral efficiency of future terahertz networks.

We apply the single-pixel imaging technique to retrieve multi-dimensional (space, time/frequency) images at terahertz frequencies by indirectly reconstructing the temporal waveform in each pixel. Moreover, we exploit compressed sensing algorithms to reduce the acquisition time.

We show the time-domain integration of terahertz pulses achieved in a sub-wavelength, tapered two-wire waveguide. Both simulation and experimental results prove the time integration functionality of this waveguide topology.

In this work, we capitalize on the unique properties of terahertz radiation to investigate nanoparticle-assisted laser-tissue interaction. We demonstrate the promising capability of the proposed technique to perform the simultaneous monitoring of laser-tissue interaction and the three-dimensional visualization of the induced photothermal damage in a non-invasive and noncontact manner.

We exploit a single-pixel imaging approach to obtain multi-dimensional (space, time/frequency) images at terahertz frequencies by reconstructing the temporal waveform in each pixel. Moreover, we apply compressive sensing to reduce the acquisition time.

In this work, the time-domain integration of broadband terahertz (THz) pulses via a tapered two-wire waveguide (TTWWG) is reported. Such a guiding structure consists of two metallic wires separated by a variable air gap that shrinks down to a subwavelength size as the movement takes from the waveguide input to its output. It is shown that while an input THz pulse propagates toward the subwavelength output gap, it is reshaped into its first-order time integral waveform. In order to prove the TTWWG time integration functionality, the THz pulse is detected directly within the output gap of the waveguide, so as to prevent the outcoupling diffraction from altering the shape of the time-integrated THz transient. Since the time-domain integration is due to the tight geometrical confinement of the THz radiation in a subwavelength gap volume, the TTWWG operational spectral range can easily be tuned by judiciously changing both the output gap size and the tapering angle. The results lead to the physical realization of a broadband, analog THz time integrator device, which is envisioned to serve as a key building block for the implementation of complex and ultrahigh-speed analog signal processing operations in THz communication systems.

In order to solve the problems of poor real-time output performance, poor resource recall performance and high execution time cost of the new media art information platform, this paper proposes to ...

This paper presents a method of deriving moment invariants under similarity transformation. The invariants sets are algebraically independent and complete. The method can be adopted for arbitrary dimension and order. This paper also presents some explicit formulas for computing invariant sets' dimension, which reveals how the number of invariants increases with moments' order and dimension elevating. We present a method for constructing moment invariant under similarity transformation.Our method can be used for deriving moment invariants of arbitrary dimension and order.Our invariants are algebraically independent and complete.We present some explicit formulas for computing invariant sets' dimensions.

The process by which art paintings are produced typically involves the successive applications of preparatory and paint layers to a canvas or other support; however, there is an absence of nondestructive modalities to provide a global mapping of the stratigraphy, information that is crucial for evaluation of its authenticity and attribution, for insights into historical or artist-specific techniques, as well as for conservation. We demonstrate sparsity-based terahertz reflectometry can be applied to extract a detailed 3D mapping of the layer structure of the 17th century easel painting Madonna in Preghiera by the workshop of Giovanni Battista Salvi da Sassoferrato, in which the structure of the canvas support, the ground, imprimatura, underpainting, pictorial, and varnish layers are identified quantitatively. In addition, a hitherto unidentified restoration of the varnish has been found. Our approach unlocks the full promise of terahertz reflectometry to provide a global and detailed account of an easel painting’s stratigraphy by exploiting the sparse deconvolution, without which terahertz reflectometry in the past has only provided a meager tool for the characterization of paintings with paint-layer thicknesses smaller than 50 μm. The proposed modality can also be employed across a broad range of applications in nondestructive testing and biomedical imaging.

A novel terahertz (THz) deconvolution technique based on the autoregressive (AR) spectral extrapolation is presented in this study. An autoregressive process is modeled based on the THz frequency components with high signal-to-noise ratio, and the missing frequency components in regions with low signal-to-noise ratio are extrapolated based on the autoregressive model. In this way, the entire THz frequency spectrum of the impulse response function is estimated. This method is able to provide a ‘quasi-ideal’ impulse response function, and therefore, significantly enhances the depth-resolution for resolving optically thin layers in the THz regime.

We present an implementation of the single-pixel imaging approach into a terahertz (THz) time-domain spectroscopy (TDS) system. We demonstrate the indirect coherent reconstruction of THz temporal waveforms at each spatial position of an object, without the need of mechanical raster-scanning. First, we exploit such temporal information to realize (far-field) time-of-flight images. In addition, as a proof of concept, we apply a typical compressive sensing algorithm to demonstrate image reconstruction with less than 50% of the total required measurements. Finally, the access to frequency domain is also demonstrated by reconstructing spectral images of an object featuring an absorption line in the THz range. The combination of single-pixel imaging with compressive sensing algorithms allows to reduce both complexity and acquisition time of current THz-TDS imaging systems.

Terahertz reflective imaging is applied to characterize the damage mechanisms in the coating on metal substrate after aging. THz frequency-wavelet deconvolution is designed to resolve the overlapping echoes due to the optically thin coating. With the decovolved THz data, different types of damages including corrosion, blisters and delamination are characterized quantitatively in three dimensions.

In this paper, we study the splitting method and two-stage splitting method for the linear complementarity problems. Convergence results for these two methods are presented when the system matrix is an H-matrix and the splittings used are H-splitting. Numerical experiments show that the two-stage splitting method has the same or even better numerical performance than the splitting method in some aspects under certain conditions.

Laser tissue soldering is an attractive approach for surgical repair. The principle is to use laser light in combination with a solder solution, such as albumin, to ‘stitch’ wound openings together. The soldering process can be enhanced by combining albumin with plasmonic nanoparticles, which act as localized absorbers that effectively transfer the impinging light into heat localized within the wound area. Advantages of laser tissue soldering over conventional sutures are a less inflammatory response of the tissue, a reduced chance of infection post-surgery, and no allergic reactions to foreign materials being introduced by traditional stitches [1]. Yet, laser tissue soldering has not been widely used for clinical applications. The underlying reason is that elevated temperatures reached due to laser light absorption and concomitant heat generation can cause significant photothermal tissue damage. Therefore, a rigorous monitoring of the heated solder solution and underlying tissue is necessary to minimize tissue damage and optimize the soldering process.